WPC0 2BPZ Courier 10cpi#|xCx6X@8;X@HP LaserJet IIIDHPLAIIAD.PRSx  @,\,-ӂX@y0(26 ZFv#|xHP LaserJet IIIDHPLAIIAD.PRSx6X@8;,\,-ӂX@a8DocumentgDocument Style StyleXX` `  ` 23pHkk#a4DocumentgDocument Style Style . a6DocumentgDocument Style Style GX  a5DocumentgDocument Style Style }X(# a2DocumentgDocument Style Style<o   ?  A.  2vetO a7DocumentgDocument Style StyleyXX` ` (#` BibliogrphyBibliography:X (# a1Right ParRight-Aligned Paragraph Numbers:`S@ I.  X(# a2Right ParRight-Aligned Paragraph Numbers C @` A. ` ` (#` 2  e  a3DocumentgDocument Style Style B b  ?  1.  a3Right ParRight-Aligned Paragraph Numbers L! ` ` @P 1. ` `  (# a4Right ParRight-Aligned Paragraph Numbers Uj` `  @ a. ` (# a5Right ParRight-Aligned Paragraph Numbers _o` `  @h(1)  hh#(#h 2   O ( a6Right ParRight-Aligned Paragraph Numbersh` `  hh#@$(a) hh#((# a7Right ParRight-Aligned Paragraph NumberspfJ` `  hh#(@*i) (h-(# a8Right ParRight-Aligned Paragraph NumbersyW"3!` `  hh#(-@p/a) -pp2(#p a1DocumentgDocument Style StyleXqq   l ^) I. ׃  2_+& QQDoc InitInitialize Document Style  0*0*  I. A. 1. a.(1)(a) i) a) I. 1. A. a.(1)(a) i) a)DocumentgTech InitInitialize Technical Style. k I. A. 1. a.(1)(a) i) a) 1 .1 .1 .1 .1 .1 .1 .1 Technicala5TechnicalTechnical Document Style)WD (1) . a6TechnicalTechnical Document Style)D (a) . 2N?a2TechnicalTechnical Document Style<6  ?  A.   a3TechnicalTechnical Document Style9Wg  2  1.   a4TechnicalTechnical Document Style8bv{ 2  a.   a1TechnicalTechnical Document StyleF!<  ?  I.   2ea7TechnicalTechnical Document Style(@D i) . a8TechnicalTechnical Document Style(D a) . PleadingHeader for numbered pleading paperP@n   $] X X` hp x (#%'0*,.8135@8:><q*"xxxxWWxxxWWkkxxx 5.0. The NMR results indicate that chromium serves as a support and inhibits any strong intermetallic interaction between copper and cobalt.   ?8  I. INTRODUCTION Several catalyst systems containing copper and cobalt in combination with a number of other elements and supports have been  CX patented13 by the IFP (Institute Francois Du Paris) investigators. The synopsis of their catalytic results is presented in Fig I for the trimetallic catalyst system CuCoCr. It is reported that: a.) in the copperrich field methanol is obtained as the main product, the activity going through a maximum for Cu/Co~ 45 and Cu/Cr~ 23; b.) FischerTropsch catalysts are obtained in the cobaltrich field; and c.) for intermediate compositions 1 < Cu/Co < 3, Co/Cr  C > 0.5, a mixture of light alcohols (C1ĩC6) is obtained with hydrocarbons as byproducts. Other investigators report  Ch" difficulties in reproducing IFP results4. It is generally believed that, besides the interatomic ratios, preparation conditions of precursors, such as pH and temperature of precipitation, drying and calcination temperatures, periods, etc., significantly influence the behavior of the catalyst. It is not clear whether the catalyst system is a compound, alloy, solid solution or a composite. The role and function of Chromium in controlling selectivity and activity are also not clear. Varying degrees of effectiveness were  C( observed when chromia (Cr2O3) was replaced by other supports such as  Cx) ZnO5. It is not clear whether these supports merely carry the metal particles in a dispersed state for thermal stability or exert an influence on the behavior of the catalyst system. +,,,ԌThe unfilled dshells responsible for the characteristic magnetic properties of the transition elements are believed to influence their catalytic properties also. Any significant interaction between the metals could cause morphological changes in the metal crystallites or perturbations in the metallic charge distribution. Either of these changes would influence the magnetic as well as the catalytic character of the sample. The Nuclear Magnetic Resonance (NMR) spectrum of Cobalt in the CuCoCr sample, and the hysteresis character of the CuCoCr composite are very sensitive to changes in the morphology or metallic charge distribution of the sample. In this investigation, we examined the correspondence between catalytic and magnetic properties through an analysis of the changes in the magnetic character of cobalt as the  ?( Cu/Co/Cr interatomic ratios vary.  ? II. EXPERIMENT  CH  Since its discovery by Gossard and Portis6 in 1959, zerofield nuclear magnetic resonance (ZFNMR) in ferromagnetic materials has provided information concerning hyperfine field, and the behavior of multidomain, singledomain, and superparamagnetic particles.  C4  Our studies710 on a series of cobalt catalysts on different supports have shown that ZFNMR is sensitive to morphological changes in the crystallite species of cobalt particles and metallic charge distribution in the vicinity of cobalt. Distinct shifts of the NMR spectrum were observed due to strong metal support  C  interaction (SMSI) between Cobalt and Titania (TiO2) support9 and  C due to intermetallic interactions between copper and cobalt10. The zerofield NMR spectra were obtained using a modified WILK'S  C nuclear Quadrupole resonance spectrometer described elsewhere8. The magnetization measurements were made using the Digital Measurements Systems(Boston, MA) Vibrating Sample Magnetometer. The CuCoCr samples were prepared following the IFP Co  C precipitation prescription2. One Molar metal nitrate solutions were mixed in the desired ratio and precipitated as carbonates by slow drop wise addition to a 7.5 + 0.5 pH sodium carbonate solution at  C 700C. The precipitate is thoroughly washed, dried at 800C for 18  C hours, calcined and reduced at 3000C in a flowing stream of hydrogen, for the same duration. Nine distinct samples representing different selectivity characters were chosen in this study. Keeping one element constant, the ratio of the other two metals is changed so that the selectivity spans from methanol to mixed alcohols to hydrocarbons in accordance with the IFP selectivity phase diagram (Fig.1).   $ The chosen samples are identified by a filled circle (.) in the  ?% phase diagram (Fig.1).  ?Q' III. RESULTS AND DISCUSSION This study clearly shows the complementary nature of the two experimental techniques employed in this investigation. NMR results (Figs. IIA and IIB) reveal perturbations in the metallic charge distribution in the vicinity of cobalt only, while the9+,,, magnetization data (Table I) show changes in the magnetic character of the composite CuCoCr system. In the cobaltrich field, Cu/Co < 1, for hydrocarbon selective catalysts, the presence or absence of Cr has no significant effect on the NMR spectra of cobalt (Fig.IIA). The pure cobalt metal powder spectrum lines are also shown in the Figure as broken vertical lines, to serve as a  C reference. The reference spectrum consists of five lines11: a fcc phase line at 213 MHz, a hcp phase line at 221 MHz, and three fault lines occurring in pairs due to stacking and twinning at 215.5 and 218.4 MHz, and 215.5 and 217.0 MHz. NMR lines (Fig.IIA) of the hydrocarbon selective catalysts (Cu/Co < 1) are confined to the normally expected region with minimal scattering, indicating that Cobalt essentially maintains its identity. However, as copper content increases beyond 50%, (Cu/Co > 1), cobalt looses its identity completely in the absence of chromia. NMR lines (Fig.IIB) appear only beyond the expected frequency region (212 222 MHz.) for cobalt, indicating that significant modifications occur in the hyperfine field at the Co nuclear site, due to charge transfer between copper and cobalt. The presence of Cr in the sample makes a dramatic difference, bringing the spectrum back into the normal region. This implies that in the presence of chromia, cobalt and copper perform their normal catalytic functions, producing hydrocarbons and methanols. The insertion of hydrocarbons into methanol chain results in the production of mixed alcohols. The magnetization results presented in Table I clearly indicate three distinct regions of ferromagnetic behavior, corresponding to the three regions of selectivity. In the cobaltrich region (Cu/Co < 1 Hydrocarbon selective catalyst), cobalt seems not easily amenable for reduction. It is possible that most of the cobalt may  C lie in spinel structure with copper and chromium as CuCo2O4 and  Cx CrCo2O4/CoCr2O4. As copper content increases Cu/Co > 1.5, we begin to detect more ferromagnetic metal, or a significant increase in percent reduction of cobalt. In the range 1.5 < Cu/Co < 5, which  C encompasses the IFPsuggested mixed alcohol region3, copper seems to promote the reduction of cobalt. Further increase in copper content leads to methanol selective region, where cobalt seems to go into solid solution with copper resulting in a considerable drop in percent reduction. In conclusion, our study showed that changes in magnetic character are associated with changes in selectivity character of the catalyst. At low copper concentrations (hydrocarbon selective), most of the cobalt seems to be locked in spinel structures. In the intermediate range (alcohol selective), copper seems to enhance the reduction of cobalt. At high copper concentrations (methanol selective) cobalt seems to go into solid solution with copper. XRD/ESCA/XPS studies are planned to verify 8#,,, these conclusions. Our zerofield NMR results indicate that chromia serves as a support dispersing copper and cobalt uniformly. We are thankful to the U. S. Department of Energy, the National Science Foundation, and the Office of Naval Research for providing financial support to perform the research. Our thanks are also due to Dr. V. U. S. Rao of the Pittsburgh Energy Technology Center, U.S. DOE, for many helpful discussions and suggestions. ,,, (table 1, figures I, IIa, IIb [NOT INCLUDED IN ELECTRONIC VERSION])  ,,, %References 1.XInstitute Francois Du Petrole (IFP) UK patents: GB 2118061A(# X(1983), GB 2158730A (1985) and US patent 4,291,126 (1981).(# 2.XP. Courty, J.P. Arlie, A. Convers, P. Mikitenkop, and A.(#(#K  ? Sugier, Hydrocarbon process. 63, 105, (1984).(# 3.XP. Courty, D. Durand, E. Freund and A. Sugier, J. Mol. Catal.  ?x  17, 241 (1982).(# 4.XXu Xiaoding, I.B.M. Doesburg, and J.J.F. Scholten, Catal.  ? Today. 2 , 125 (1987).(#  ?  5.XM. Ichikawa, Bull. Chem. Soc. Japan. 51 , 2268, 2273 (1978).(#  ?  6.XA.C. Gossard and A.M. Portis, J. Appl. Phys. 31 , Suppl., 205 (1960); and A.C. Gossard, A.M. Portis, M. Rubinstein, and R.H.  ?( Lindquist, Phys. Rev. 138 , A1415 (1965).(# 7.XA.N. Murty, A.A. Williams, R.T. Obermyer and V.U.S. Rao, J.  ? Appl. Phys. 61 , 4361 (1987).(# 8.XA.N. Murty, A.A. Williams, R.T. Obermyer, V.U.S. Rao and R.J. Gormley, pp 6874 catalysis (1987), edited by J.W. Ward (Elsevier, Amsterdam,1988).(# 9.XA.N. Murty, M. Seamster, A.N. Thorpe, R.T. Obermyer and V.U.S.  ? Rao, J. Appl. Phys. 67 , 5847 (1990).(# 10.XA.N. Murty, J. Washington and M.A. Akundi (to be published).(#  ?0 11.XL.E. Toth and S.F. Ravitz, J. Phys. Chem. Solids. 24 , 1203 (1963). (# ,,, #GRADUATE AWARD h#IVONNE SANTIAGO NEW MEXICO STATE UNIVERSITY ,,, #GRADUATE AWARD Ivonne Santiago Graduate Student, Department of Civil Engineering, New Mexico State University, Las Cruces, New Mexico 88003   X` hp x (#%'0*,.8135@8:100P   p  HDTMA@# C19H42N+@# Brsalt@# 284@# 100  !*Formula Weight of Organic Cation +Solubility of Salt ('0*((Ԍ Table 2. awysical Characterization of Zeolites c !ddxL< Addxx ddd c 8 8 x  TILDEN ST. CLOUD CH8  x EXTERNAL CEC, meq/100g   30  15   20   INTERNAL CEC, meq/100g  60  35   60    TOTAL CEC, meq/100g 90 50  80 P   CLAY, % 40 10 25P   CLINOPTILOLITE, %( 20( 60( 35   EXTERNAL SURFACE AREA, m2/g 56.8 14.9 55.4  ( EQUIV. DENSITY, meq/"2  5.3E23  10.1E23  3.6E23   CHARGE DENSITY, CHARGE/"28 .03188 .06068 .0217     "2/CHARGE 31.45 16.50 46   8  Table 3 ^ Addxx ddd addx@awl ^    P ZEOLITEx! TAILORING AGENT# SLOPE# CORRELATION COEFFICIENT  @ TILDEN %MwCETYL % .57 % .995  # 8' EHDDMA8' .418' .995%0*((   %  HDTMAH .533H .995  0 ST. CLOUD` CETYL` .52` .975  H x EHDDMAx .37x .995  `  HDTMA .42 .979  x  CH CETYL! .51 .993     EHDDMA NA NA    HDTMA .63 .972   CHABAZITE CETYL .42 .993    EHDDMA NA NA H   P HDTMAP .73P .989H    &Chromium * Chromium is used in a variety of industrial applications, including electroplating and as a corrosion inhibitor in cooling towers (Udy, 1956). Up to a few years ago, this metal was the favored<(0*0*0* corrosion control agent in cooling towers (Norvelle, 1992). Cooling water blowdown (waste) was dumped into rivers, pits, lakes and oceans. During the 1950's chromates were also used as a highway deicing agent in the United States. F ` ` Chromium (Cr) occurs in the +2, +3 and +6 oxidation states in water. The divalent state is rarely found in field conditions because it becomes rapidly oxidized to +3 in the presence of atmospheric oxygen (Baes and Mesmer, 1986). ` ` Insoluble Cr(III) occupies much of the Chromium EhpH diagram (Brookings, 1988). Chromium (III) is less toxic than Cr(VI) (Baes and Mermer, 1986), however, it can be oxidized to form the carcinogenic Cr(VI) in the presence of oxygen. ` ` The predominance diagrams for Cr(VI) extend over large ranges of Eh and pH (Brookings, 1988). Cr(VI) is soluble and hydrolyses extensively in'0*(( water, producing only neutral and anionic species as shown in Figure 1 (Baes and Mermer, 1986). These properties insure rapid migration through soils, which are unable to undergo anion exchange with these hazardous materials. ` ` Hexavalent chromium can be treated by first reducing it to trivalent chromium in the presence of a reducing agent such as gaseous sulfur dioxide (SO2) or a bisulfide solution (NaHSO3). In addition, there are three commercially available methods that use the reducing potential of iron and/or iron salts to reduce hexavalent chromium (EPA, 1985). Because trivalent chromium is only soluble under acidic conditions, the pH is adjusted to a range of 9.0 to 9.5, at which Cr(III) will precipitate as a hydroxides (EPA, 1985). These procedures have several disadvantages, including low reduction efficiency, slow reduction kinetics (Patterson, 1985), increase in product TDS, and large volumes of waste generation. Anion exchange is the only treatment method reported to be economical (Patterson, 1985), simple and effective (Norvelle, 1992). -  )Zeolites%0*((Ԍ-` ` Zeolites are a group of minerals in the tectosilicate class of silicate minerals. They comprise a large family of naturally occurring crystalline, hydwted aluminosilicate minerals containing alkali and alkaline earth cations, such as sodium, calcium, and potassium, as well as water, in their structural framework (Zamzow et al, 1990). Zeolites have a three dimensional sawucture based on the linking of [SiO4]é4 and [AlO4]é5 coordination polyhedra (Dyer, 1988). All the oxygens at each tetrahedral corner are shared with other similar tetrahedrons. Since there are no unshared oxygens, the [(Si+Al):O] ratio is always 1:2 in zeolites (Boles et al, 1986). This sharing of each oxygen in the SiO4 tetrahedra results in an elctricallyneutral structure. Isomorphic substitution of Aluminum in the AlO4 tetrahedra creates a negatively charged structure that is balanced electrically by exchangeable cations. ` ` There are several ways in which the tetrahedrons can be linked (Dyer, 1988). The various bonding patterns of the tetrahedra result in interconnected and repeating channels throughout the zeolite minerals crystal structure. Cations attach to the minerals atomic lattice to electrostatically balance the negative charge'0*(( induced by the aluminum tetrahedra in these internal channels and on the external surface of the zeolite, . These cations, typically Na+, K+, Ca+2, and Mg+2, give zeolites their cation exchange capacity (Dyer, 1988). ` ` Zeolites can be formed in a variety of geological environments. They typically occur as dispersed crystals in the gas bubble cavities of extrusive igneous rocks (Barrer, 1978). Also, massive deposits of nearsurface, flatlying zeolites are formed from precursor materials such as volcanic ash, clays, feldspar, biogenic silica, and forms of quartz. It is believed that many of these massive zeolite deposits have formed over time following the deposition of volcanic ash in saline, alkaline lakes (Dyer, 1988). ` ` Since the discovery of zeolites in 1756 by F. A. F. Cronstedt (Boles et al., 1986), thirtynine naturally occurring zeolite species have been characterized. However, only seven, mordenite, clinoptilolite, ferrierite, chabazite, erionite, phillipsite, and analcime, occur in sufficient quantity to be considered as viable mineral resources (Zamzow et al, 1990). Also, one hundred synthetic species have been reported in the literature (Dyer, 1988).'0*((Ԍ` ` The clinoptilolite framework has one eightring oxygen window and one tenring oxygen window, which define two perpendicular channels. The free apertures of the two interconnected channels are 4 x 5.5 " and 4.4 x 7.2 " (Barrer, 1978). ` ` A representative value of Si/Al ratio for clinoptilolite is around 4, and four cation sites per unit cell have been found in its channels. The idealized formula for this zeolite is (Dyer, 1988): T!# ddddd= dd/x#Na_6[(Al_2O_6)(Si_2O_30)] * 24H_2O x6X@X@x6X@X@x6X@X@_NaB_Al_O:_Siz_O _H _O+6R_[_(2+2+6J_)_(*+2+30_) _]_24b +2_T$(#(#(#(#X!!'#$ 1dddddddd (1) !1dddddddd (1)  ` ` Clinoptilolite exhibits great structural stability up to 700oC in air and retains its structural integrity after six months exposure to 8M Nitric acid (Dyer, 1988). ` ` Zeolites are used in detergents to enhance their cleaning efficiency; for enrichment of gases of the air (Dyer, 1988); for ammonia removal from secondary effluent (Mercer et al., 1970); for heavy metals adsorption (Zamzow et al., 1990), in the treatment of radioactive wastes (Boles et al., 1988); as dietary supplements for animal and fish (Mumpton and Fishman, 1977); and for removal of leacheate contaminants (Chan et al., 1980). #ZMATERIALS AND METHODS 'Zeolites Used0'0*(('#!0Ԍ-` ` The zeolites used in this research are the clinoptilolite type. The main cations present are alkali metals like Na+ and K+. ` ` Two types of clinoptilolite zeolites were used. The first zeolite was provided by the Zeotech Division of Leonard Minerals (Albuquerque, New Mexico) from their mines in Tilden, Texas. This zeolite is referred herein to as the Tilden Zeolite. The second zeolite was provided by the St.. Cloud Mining Company (Truth or Consequences, New Mexico) from their mine located in Winston, New Mexico. This zeolite is referred to herein as St. Cloud zeolite. p Characterization of Zeolites -` ` Physical characterization of the zeolites was made by xray diffraction (XRD), cation exchange capacity (CEC) and external surface area. XRD analyses for the Tilden and St. Cloud zeolites were made by our collaborators at Texaco, Inc. (Houston, Texas). The XRD's for the zeolites were later confirmed by the Department of Geology at New Mexico State University (Las Cruces, New Mexico) and the New Mexico Bureau of Mines (Socorro, New Mexico). %0*((Ԍ` ` CEC's of the Tilden and St. Cloud zeolites were determined in our laboratories. The total cation exchange capacity was determined using a modified procedure of the method utilized by Rhodes (1982). The saturation solution was a 1.0N solution of sodium acetate trihydrate. The extracting solution was a 1.0N solution of ammonium acetate. The zeolite sample mass used was 2 grams, rather than 4 to 5 grams recommended by Rhodes (1982). ` ` The external CEC (ECEC) of the zeolites were determined using a modified procedure of the Ming and Dixon (1987) method. The determination of the external exchange sites was performed by using tetramethylammonium ions rather then tertbutylammonium ions. Our ECEC results are comparable to those reported by other laboratories for the same type of zeolitic deposits. ` ` External surfaces of the zeolites were determined using the multipoint BET method by Sandia National Laboratories (Albuquerque, New Mexico). This parameter allowed us to compute the charge density per area of the zeolites by dividing the ECEC by the surface area. #ZTailoring Agents Used%0*((Ԍ-` ` Two organic cations were used as tailoring agents, namely, Ethylhexadecyldimetyhylammonium (EHDDMA), and Cetylpyridinium (CETYL). Table 1 shows some relevant properties about these compounds. ` ` Chemical representation of these tailoring agents are also shown in Figure 2. It is important to note that these compounds have a long and flexible alkyl chain. Various properties arising from the different characteristics of the tailoring agents may be used to observe how these affect Cr(VI) sorption onto zeolites. In addition to these tailoring agents, other tailoring agents of relatively compact, rigid and symmetric characteristics, such as Tetramethylammonium (TMA) and Tetraethylammonium (TEA) were unsuccessful for removal of Cr(VI) in preliminary studies run in our laboratories.  Surface Modification/Tailoring of Zeolite -` ` The two natural zeolites were washed with tap water to remove fine particles that could interfere with with atomic absorption analysis. Tailoring of zeolites was done by adding appropriate quantities of organic cations into eight 100 g/L suspension. The zeolites were tailored at doses equal to 0, 50,' 0*(( 75, 100, 150, 200, 300 and 400% of the external * 0 Surface Modification of Zeolites  CH qand Cr+6 Removal Studies *  C ( Surface Modification (Tailoring) and Cr+6 Removal Studies were made following the procedure described by Santiago et al (1992). RESULTS AND DISCUSSION ( * \ Characterization of Zeolites * ( Table 2 shows the results of CEC's run in our laboratories. This table also shows zeolite deposit compositions based on Xray diffraction studies, external surface areas, and charge densities. Charge densities were obtained by dividing the ECEC values by the corresponding surface areas. As it can be observed from this table, St. Cloud zeolite has both the lower external and internal CEC. However, the CEC of interest to us is the external CEC (ECEC), since sorption of contaminants in zeolites can only occur at the surface of the zeolite, because internal CEC is not approachable by the tailoring agent. This is due to the interconnected channels, which do not have an area larger than the projected area of the tailoring agents used. The larger ECEC are those of Tilden and CH zeolites. As can be seen from Table 2, St. Cloud zeolite is the zeolite with the highest clinoptilolite content, whereas, Tilden zeolite contains more clay. Table 2 also shows that CH has the lowest charge density of  C0# three zeolites, thereby has the largest #2/charge. In contrast,  C# St. Cloud has the largest charge density and the lowest #2/charge of all. *  Tailoring Agent Adsorption Studies * ( The actual amount of tailoring agent that is adsorbed by the zeolite should be known in order to understand the sorption process of Chromium onto a tailored zeolite. Figures 3 to 5 show how much of the tailoring agent added was actually exchanged or adsorbed by the zeolite. The horizontal lines show the point+,,, where the external CEC of the zeolite is satisfied. The 1:1 line represents an ideal adsorption condition, where all the tailoring agent added is adsorbed or exchanged. It can be observed from these figures that in order to satisfy the external CEC of the zeolite, additional tailoring agent in excess of the ECEC must be added. Beyond the ECEC of the zeolite, interactions between the long alkyl chains of these tailoring agents make possible further adsorption onto the zeolite possible. This suggests that after neutralization of the zeolite due to exchange of the positively charged organic tailoring agent with cations in the zeolite, charge reversal of the zeolite may occur. The result is a tailored zeolite with a net external positive charge on its surface. This phenomenon has been observed and reported by Greenland and Quirk (16, 17). The slopes of these lines give us an indication of the efficiency with which a tailoring agent is adsorbed by the zeolite. Table 3 presents the slopes of the lines in these figures and the coefficient of correlation. The high correlation coefficients suggest that there is a strong linear trend for all cases presented. The slopes indicate what percentage of the tailoring agent added is actually adsorbed. For instance, it can be said that 57% of the CETYL added to the Tilden zeolite is effectively adsorbed. It is important to note that the tailoring agent most effectively exchanged on both Tilden and St. Cloud zeolites was CETYL, and that the least efficiently adsorbed was EHDDMA. Lower adsorption efficiency by EHDDMA may be due to the fact that the ethyl group causes a fixed orientation of the EHDDMA molecules. Such an arrangement may reduce interactions between the long chain of the tailoring agent and the surface of the zeolite. This molecular configuration probably hinders further adsorption of a multilayer coat and prevents further adsorption on the surface of the zeolite (15). On CH zeolite, the tailoring agent most effectively adsorbed was HDTMA.  Hexavalent Chromium Removal *  Figures 6 through 8 show the linear partition coefficients  C (mL/g) for Cr+6 removal using Tilden, St. Cloud zeolites tailored with CETYL, EHDDMA and HDTMA, and CH zeolite tailored with CETYL and HDTMA. These figures show that little or no removal is obtained with the natural zeolite. However, exchange of the natural organic cations for the organic tailoring agent greatly  C! enhances the adsorption capacity of Cr+6 onto the tested zeolites.  C0# Figure 6 shows that Cr+6 removal using Tilden zeolite tailored with CETYL and EHDDMA only occurs at an added dose of tailoring agent equivalent to 200% of the ECEC or more. This ECEC corresponds to the dosage of tailoring agent that fulfills the ECEC of the zeolite, as was shown in Figure 3, after which charge reversal on the surface of the zeolite occurs. However, in the case of HDTMA, chromium removal occurs at dosages below the ECEC.  Ct) Figure 7 shows that Cr+6 removal using St. Cloud zeolite occurs even prior to saturation of the external CEC. This phenomenon may be due to the higher charge density of St. Cloud+,,, zeolite (Table 2). By having a larger charge density, charge reversal of the zeolite might occur at tailoring agent dose lower than the ECEC due to a crowding effect on the surface of the zeolite.  C  Figure 8 shows that for the case of CH zeolite, Cr+6 removal also occurs at even prior to saturation of the external CEC. Normalization of the equilibrium constants was made by dividing the equilibrium constant by the number of charges of tailoring agent adsorbed on the surface of the zeolite to compare  C  the effectiveness of Cr+6 removal for both zeolites and both tailoring agents. This equilibrium constant is herein referred  C to as K*. Figures 9 through 11 show the logarithm of K* for Tilden and St. Cloud and CH zeolites, respectively. These figures suggest that the mechanisms of removal are similar for each zeolite, since the curves for each zeolite follow similar patterns.  CT  =Mass of Cr+6 Removed/Mass of Zeolite: Insights on pH effect * ( In this phase of the study, the solutions were not buffered. However, by plotting the mass of chromium removed per gram of zeolite versus the mass of tailoring agent added per gram of zeolite at the different pH values obtained, a preliminary  C inference on the pH effect on Cr+6 removal can be made. It was observed that lower the pH the higher the mass of chromium removed. Figure 12 shows an example the mass of chromium removed per gram of zeolite versus the mass of tailoring agent added per gram of Tilden zeolite tailored with CETYL. As it can be ob C served from this figure, removal of Cr+6 is definitely enhanced at lower pH values. Figure 8 shows that in this particular case, pH values were higher than 7.0, due to the higher carbonate content in the zeolite that served as a buffer. Under such  C experimental conditions, the predominant Cr+6 species was CrO42, as can be seen from Figure 1. This suggests that the most likely  C mechanism for Cr+6 removal is anion exchange. This mechanism occurs with both tailoring agents tested. In the cases of St. Cloud and CH zeolites, the pH was lower than 6.0. At these low pH conditions and corresponding concen C trations of Cr+6, the predominant species is HCrO4é. H2CrO4 is a very strong acid (4), therefore, possible oxidation of the tailoring agent could be taking place. However, under these acidic conditions, Cr precipitation is highly unlikely. %XCONCLUSIONS *  CL# ( Zeolites provide a unique, viable alternative to remove Cr+6 from solution. This mineral can be used in a number of ways to  C$ remove positively charged compounds such as NH4+; neutral contaminants such as Benzene, Toluene and Xylene; and negatively charged compounds such as the ionized species of Hexavalent  C<' Chromium (HCrO4é and Cr2O7é2) by varying the dosage of tailoring agent added. The former may result from charge reversal at the surface of the zeolite. Results also suggest that the clinotilolite content, the ECEC of the zeolite and the molecular struc C`* ture of the tailoring agent affect the capacity to remove Cr+6. ,+,,,Ԍ%XFUTURE WORK * ( Further studies are in progress in order to study the  CX effects of controlling the pH on adsorption capacity of Cr+6 onto different zeolitic deposits. Also, equilibrium studies will be performed with optimum combinations of tailoring agents, tailoring agents dosages and zeolites. Column studies will be performed as a practical way to implement this technology on a full scale. Economic viability of this alternative procedure will be studied and compared to other  C methods currently used to remove Cr+6. ",ACKNOWLEDGEMENTS * ( The author wishes to acknowledge the support from the National Science Foundation, Texaco, Inc., the Waste Education and Research Consortium, and the University of Puerto Rico, Mayaguez Campus. ,,, %REFERENCES *   ?  4.XBaes, C.F., and Mesmer, R.E., The Hydrolysis of Cations, R.E. Krieger Publisher Co., Malabar, Florida (1986).(# 10.XBoles, J.R.,and E.M. Flanigen, and A.J. Gude, and R.A.  ? Sheppard, and R.L. Hay, and F.A. Mumpton Mineralogy and  ? Geology of Natural Zeolites: Reviews in Mineralogy, Volume 4, Frederick A. Mumpton, Editor (1986).(#  ?@  5.XBrookings, D.G. EhpH diagrams for Geochemistry, SpringerVerlag, New York (1988).(# 15.XCazaresRivera, E., "Removal of SingleRing Aromatics by Tailored Zeolites", Doctoral Dissertation, New Mexico state University, 1992. Printing in Progress.(# 13.XChan, P.C., and J.W. Perna, and R. Traltner, "Evaluation of Sorbents for Industrial Sludge Leachate Treatment", Report EPA600/280052, 56 (June, 1980).(#  ?  9.XDyer, A., AN Introduction to Zeolite Molecular Sieves, John Wiley and Sons, Inc (1988).(# 16.XGreenland, D.J., and J.P. Quirk. "Determination of the Total Specific Surface Areas of Soils by Adsorption of Cetyl  ? Pyridinium Bromide," Soil Science, 15, 178191 (1964).(# 17.XGreenland, D.J., and J.P. Quirk. "Surface Areas of Soil  ?0 Colloids." Transactions of Commissions IV and V., Int. Soc.  ? Soil Sci. New Zealand, 7987 (1962). (# 11.XMercer, B.W., and L.L. Ames, and C.J. Toohill, and W.J. Van Slyke, and R.B. Dean, "Ammonia Removal from Secondary Efflu ?P ent by Selective Ion Exchange", J. Water Pollution Control  ? Fed, 42, 95107.(# 12.XMumpton, S.A., and P.H. Fishman, "The Applications of Natu ? ral Zeolites in Animal Science and Aquaculture", J. Animal  ?p Science, 4, 11881203, (1977).(#  ?8  3.XNorvelle, N.R., "Removal of Chromium from Water", Presented  ? at the 5th Annual Hazardous Water Management Conference, Sandia National Laboratory, March 12, 1992.(#  ?  7.XPatterson, J.W. Industrial Wastewater Treatment Technology, Second Edition, Butterwoths, Boston (1985).(# 2.XRichard, F.C., and A.C.M. Bourg, "Aqueous Geochemistry of  ? Chromium: A Review," Water Res., 25, Number 7, pp. 807816 (1991).(# 14.XSantiago, I., and V.P. Worland, and E. Cazares, and F. Cadena, "Adsorption of Hexavalent Chromium onto Tailored  ? Zeolites," Proceedings of the 47th Industrial Waste Confer ? ence, Purdue University, 1992, Printing in Progress. (#  ?!  1.XUdy, Marvin J., Chromium: Chemistry of Chromium and Its  ?`" Compounds, Volume 1, Reinhold Publishing Corporation, New York (1956).(#  ?#  6.XU.S. Environmental Protection Agency, Environmental Pollution Control Alternatives: Reducing Water Pollution Control  ?% Costs in Electroplating Industry, USEPA/625/585/016, (September, 1985).(# 8.XZamzow, H.J., and B.R. Eichbaum, and K.R. Sandgren and D.E. Shanks, "Removal of Heavy Metals and Other Cations from  ?( Wastewater using Zeolites," Separation Science and Technolo ?h) gy, 25, 15551569 (1990).(# *,,, Table 1. Properties of Tailoring Agents Used ^ ddx !ddxL<x@X ^  <  8 Chemical Formula Form Used  Cp F.W.*  ?< (g/mol)  Cp Solubility+  ?< (g/L)< T  EHDDMAT  C C20H44N+X BrsaltX 298X 100T T  CETYL  C C21H38N+ Clsalt 304 >100T   X HDTMA,  C4 C19H42N+0 Brsalt0 2840 100   Table 2. Physical Characterization of Zeolites c !ddxL<x@X Addx  dd c  p   TILDEN ST. CLOUD CHp    EXTERNAL CEC, meq/100g    ?  30   15   20    INTERNAL CEC, meq/100g  ?`  60  35   ?`  60     TOTAL CEC, meq/100g  ?x  90  50  80 P  CLAY, %X  ?  40 X 10X 25P P  CLINOPTILOLITE, % 20  ?  60  35P  X EXTERNAL SURFACE AREA, m2/g  ?0  56.8  14.9 55.4 T   CH EQUIV. DENSITY, meq/"2 5.3E23  ?H  10.1E23  3.6E23T T   C CHARGE DENSITY, CHARGE/"2h .0318h  ?  .0606 h .0217T     C "2/CHARGE 31.45 16.5  ?  46    h ,,, Table 3. Slopes of Adsorption Isotherms of Tailoring Agents. ^ Addx  dd addx l ^   8 h ZEOLITE8 TAILORING AGENT SLOPE CORRELATION COEFFICIENT8 P  TILDENP CETYLP .57P .995P P   EHDDMA .41 .995P P P  HDTMA .53 .995P P  ST. CLOUD@ CETYL@ .52@ .975P P   EHDDMA .37 .995P P @  HDTMA .42 .979P P   CH0 CETYL0 .510 .993P      HDTMA .63 .972  0  ,,, #x6X@K^X@# LIST OF FIGURES [not included in electronic version] *  Figure 1.` ` X Chemistry of Hexavalent Chromium(# Figure 2.  Organic Tailoring Agents(# Figure 3.  Tailoring Agent Adsorption on Tilden Zeolite(# Figure 4.  Tailoring Agent Adsorption on St. Cloud Zeolite Figure 5.  Tailoring Agent Adsorption on CH Zeolite Figure 6.` `  X Linear Partition Coefficients for Chromium Removal Using Tilden Zeolite(# Figure 7.  Linear Partition Coefficients for Chromium Removal Using St. Cloud Zeolite(# Figure 8.` ` X Linear Partition Coefficients for Chromium Removal Using CH Zeolite(# Figure 9.  Normalized Linear Partition Coefficients for Chromium Removal Using Tilden Zeolite(# Figure 10.  Normalized Linear Partition Coefficients for Chromium Removal Using St. Cloud Zeolite(# Figure 11.  Normalized Linear Partition Coefficients for Chromium Removal Using CH Zeolite(# Figure 12.  Mass of Chromium Removed vs Mass of Tailoring Agent Added on Tilden Zeolite Using CETYL(# !,,, figures 112 [not included in electronic version]",,, STUDENT RESEARCH ABSTRACTSX#,,, PRECOLLEGE STUDENT PROGRAM COMPREHENSIVE REGIONAL CENTERS FOR MINORITIES [CRCM]$,,,  ?  3'3'Standard'3''Standardor numbered pleading papery0X% '3''Standardor numbered pleading paper3'3'StandardrJet IIISi (Addi(ѰX%% 1  ?  Name of Presenter: Samori Augusto Institution: University of Pennsylvania Classification: Junior Major Area of Study: Computer Science and Engineering NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Bonnie Webber  ?  The Route Finder The Route Finder is a system to be used for transportation within a city. It will allow the user to input the addresses of the starting and destination points and to output an optimal path for the driver. To produce this optimal path the system will take into account factors that would affect the driver's ability to reach the destination within a reasonable time. These factors include the speed limit of the streets to be traversed, the pattern of traffic congestion of the streets, whether there is ongoing construction or repair of roads, effects of current weather on road conditions, etc. After evaluation of these factors the system outputs a sequence of street segments that will take the driver to the destination. The system is implemented with programs written in the C programming language. 2  ?  Name of Presenter: Adrian Banegas Institution: Montwood High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Steve Riter  ?  Rolling on the River The question posed in this experiment was "Where is the highest most probable number of coliforms in the Rio Grande river?" I believe that due to the increasing amounts of pollution (agricultural and human wastes) the southern part of the river will have a higher M.P.N. level of coliform bacteria. Coliforms are spiral bacteria usually found in the small intestines and can cause a number of diseases, such as hepatitis and cholera. The two main causes for the presence of coliform bacteria in water are human defecation into the water and the use of animal dung for fertilizer on farms. Samples were obtained at every two miles for twenty miles then the M.P.N. test which approximates the amount of coliform bacteria there is in a body of water was applied. The highest concentrations of coliforms are found in the southern part of the Rio Grande confirming the hypothesize.  ?'  3 Name of Presenter: Raul Bautista and Mike Ivicek Institution: Agua Fna High School and Dobson High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: James Fousek and Deborah Lowther+%,,,Ԍ ?  ÙThe Effect of Low pH Solutions on Germination Rates of Seeds The purpose of this study was to determine if the germination rate of radish seeds is effected by exposing the seeds to varying levels of acetic compounds (similar to acid rain). The investigation used four samples, each with a different pH level. The control sample had a neutral pH. The three remaining samples varied by one level each, ranging from a pH of 3 to a pH of 5. The following conditions were kept consistent across all variables: soil (type and amount), light source (type and length of exposure), water (type, amount, time applied), temperature and location. Testing for each sample consisted of the following steps: "Soak (12 hours) equal amounts of seeds in each of the four pH solutions. "Place seeds in prepared corresponding petridish. "15 day observation period. Results are being compiled and analyzed. Conclusions will be presented. 4 Name of Presenter: Tina Billedeaux and Shannon Clairmont Institution: Ronan High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Mark Decker Water Quality Student "Heros" Water is an agent that binds one society to another society. Water awareness is important for all people, today and into the future. It involves a process of education. The scientific method provided the process for an environmental analysis of a local stream to be completed by students from Ronan High School's Montana Natural History class. Standard water quality sampling techniques were used to complete the environmental analysis of Ronan's Spring Creek. Several tests were completed, velocity, volume, habitat type, and aquatic insect surveys. Other parameters that were documented at each stream site included geographical information, aquatic vegetation, personal observations, and rough sketches of the organisms at the stream sites. In summary, the environmental analysis of Ronan's Spring Creek will serve as a baseline study for comparison by future students and water quality agencies involved with Spring Creek. 5 Name of Presenter: Kamafi Byrd+&,,,ԌInstitution: Beaumont High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Robert Cole An Investigation of the Possibilities of Three Types of Time Travel Investigations of time travel as a method to understand the origin or demise of the universe have generally centered around the  C@ Einstein Time Barrier Equation (E=mc2). The purpose of this study was to investigate the possibility of superimposing quantum states, looping around cosmic strings, and sending signals faster than light by comparing these types of time travel to Einstein established laws of space time travel. Based on Einstein's Time barrier Equation, it was hypothesized that superimposing quantum stated (traveling through time), carries an extremely low possibility, that looping around cosmic strings in a verifiable method of time travel, and that sending signals faster than light is impossible. ',,,  ?  6 Name of Presenter: Kendall Campbell Institution: Florida A&M University Classification: Freshman Major Area of Study: Computer Science NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Ralph W. Turner  ? The Camera and the Human Eye It would seem that the human eye and camera are very similar devices, consisting of light sensitive materials and lens; however, the differences between the two are much greater than the similarities. The major difference between the two systems is the existence of a scanning system for visual perception of a scene by the eye/brain combination. A high level of resolving power and color discrimination exists only at the small fovea where the visual axis intersects the retina. A complete perception of the scene is built up by a series of small irregular movements of the eye, called saccade, to cover the region of interest by integration of the small, sharp images. The conventional camera does not use such a scanning system at all, although other systems such as television cameras and infrared imaging devices employ a regular line scanning method for obtaining images. 7 Name of Presenter: Nivia Col;n D1az Institution: Rexville High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Ivn Cardona Torres Patterns in Prime and Compound Powers Phase III In the first phase the researcher found defined patterns in the last digits of the results of the 2 to 9 bases raised from the 2nd to the 10th power. In the second phase the symmetric bases of phase one were analyzed.  The purpose of this phase is to analyze if there are defined patterns in the result of the 1 to 100 bases raised from the 1st to the 45th power, looking at the next to last digits. The hypothesis is: If there are defined patterns in prime and compound powers in the next to last digits of the results, then the extension of these patterns can be predicted. Results demonstrate that: there is a defined pattern in prime and compound powers, looking at the next to last digits of the results, and the researcher can predict the extension of these patterns. In the fourth phase of this investigation, RSA, a cryptographic system, will be used to codify messages. +(,,,Ԍ8 Name of Presenter: Chastity Dunn and Dale Francisco Institution: Mayfield High and Navajo Pine High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Vincente Llamas "Behold, A New World:" A Supercomputer Ray Tracing Project Chastity Dunn, a junior at Mayfield High School in Las Cruces, New Mexico, spent six weeks at a resident summer Math/Science Camp at the Southwestern Indian Polytechnic Institute. Her project concentrated on creating a three-dimensional animated world of natural scenes. The project included background training in telecommunications allowing the personal computer and supercomputer to interface. Chastity studied a Wireman modeling system on the personal computer and a MESA rendering package in the Supercom puter. She interactively constructed three-dimensional worlds using standard geometric shapes with advanced image mapping and textures. Dale Francisco, a senior at Navajo Pine in Navajo, New Mexico, worked on a related aspect of the project by creating a fly-by of the earth using the same method. The model included an approach to a cloud-covered earth up to a near-orbit of the earth so that its topography could be seen. Both students worked with three groups creating scenes of Modern Day Earth, the solar system moving through a black-hole and a natural Tracing Project.  ?p  9 Name of Presenter: Jesus Gonzales Institution: San Antonio High School NSF Sponsored Program: CRCM  ?X  Faculty Advisor or Mentor: Dr. Richard Howe Clean Heavy Duty Diesel Engine Project The goal of the CHDDE research project is to investigate, define, and solve the problem that cause particulate, nitrous oxide (NOx) and hydrocarbon (HC) emissions in the typical diesel engine (35400kw range). The purpose is to improve the current engine emissions levels to meet those required by the Clean Air Act passed by the U.S. Congress for 1995: HC g/bhphr (gram per brake horse power hour), PM 0.1 g/bhphr, Nox 2.0 g/bhphr, and emission durability of 100,000 miles; and any anticipated requirements for the year 2000 and beyond. A standard test to determine engine speed utilizes a frequency counter. This sensor counts the number of gear teeth on the power shaft using a magnetic pickoff sensor which reads the magnetic field created by the hall effect as each tooth passes by. Using a simple calculation these pulses are translated into a readable frequency wave and set of data points. *),,,ԌEngine data acquires by the computer/engine hookups or manometers, (pressure, temperature, valvelift, bore size, engine speed (rpm), air flow rate (Lb/Min), torque (FpLb), and more) help to develop a specific profile of the engine and determine the best way to reduce overall emissions and improve efficiency. The CHDDE project is a multiclient consortium which reflects the widespread concern with protecting the environment now sweeping through the engine industry. Research is being conducted by Southwest Research Institute.  ?`  10 Name of Presenter: Aaron Gutierrez and Alma A. Barraza Institution: Camelback High School and Carson High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: James Fousek and Deborah Lowther The Effect of Insulation of the Interior Temperature of a Structure The purpose of this study was to determine which type of insulation is most effective in maintaining the largest difference between interior and exterior temperatures of a structure. This investigation used five identical structures. Of the five structures, one was a control with no insulation. The remaining structures were used to test four different types of insulation. Testing conditions (thickness of insulation and placement) were kept consistent for each of the structures. Testing for each structure consisted of the following steps. "alcohol thermometers placed inside (viewed through the window) "all seams caulked to eliminate air currents "initial airconditioned temperature was recorded "moved outdoors; placed in full sun on lawn "temperature changes monitored and recorded. Results are being compiled and analyzed. The conclusions will be presented at the Conference. 11 Name of Presenter: Guillermo Hurtado and Joe McFee Institution: Marie Currie High School and Hyde Park Career Academy NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Eric Hamilton Mathematical Explorations Presentation describes mathematical explorations using software written by copresenters, who built the computers used to perform the explorations. Explorations focus on number theory, analysis, and fractals. Device drivers facilitating use of LEGO engines with Pascal programs are also discussed, along with a review of related circuitry experiments. +*,,,Ԍ ?  Ù12 Name of Presenter: Howard Manning Institution: Beaumont High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Jerry L. Bryant Detection of Local and Systemic Spread of Turnip Mosaic Virus In Turnip Plants The purpose of this investigation was to determine whether tissue print immunoblotting, a recently developed technique, could be used to follow the spread of turnip mosaic virus (TuMV) infections in host plants. The hypothesis was that this technique has enough sensitivity and resolution to allow histological localization of the virus to specific cell types and tissues in infected plants. Seven Top turnip plants, (Brassica sp., Burpee Seed Company) were infected with a preparation of TuMV by applying a solution containing the virus to a leaf by rubbing with a glass rod after dusting the leaf with carborundum. Control plants were mock infected with the virus preparation buffer only. At different times postinfection, 12 mm crosssections of different parts of the infected plants were printed by pressing to nitrocellulose filters. These filters were probed for the presence of TuMV using antibodies specific to the viral coat protein. At 17 days postinfection, virus was found throughout the mesophyll cells and vascular bundles of the originally infected leaf but not in other leaves of the plant. After 27 days however, TuMV had spread to other leaves of the plant and was concentrated in the vascular bundles of the stems, petioles, leaf veins, and leaf mesophyll cells as a result of the systemic spread of the virus. Therefore tissue print immunoblotting can be used to assay for TuMV spread in infected plants as well as for immunolocalization of TuMV at the subcellular level.  ?   13 Name of Presenter: Miguel E. MarreroMedina Institution: Carvin High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Gary Toranzos Use of Coliphages as an Alternate Indicator of Fecal Contamination  ?`" in Water and its Possible Applications in Sediments Biological water quality in Puerto Rico has been affected by sewage discharges, which may cause health problems. Traditionally, total coliforms, fecal coliforms and enterocci have been used to determine the biological water quality. However, these indicators have also been found in areas where no fecal contamination was observed. Coliphages (virus that infect Escherichia coli) have been proposed as an alternate indicator of fecal contamination. Little is known about the behavior of this virus in tropical aquatic sediments even in waters that meet biological quality standards. In this study, we developed an alternate method to determine the microbiological quality in tropical waters and++,,, sediments. Samples of water and sediments were taken from pristine and sewage water bodies. The membrane filtration technique was used for the bacteriological assays, and a direct phage assay mixing a 100ml aliquot with 100ml of the culture medium and the host bacteria E. coli C3000 (ATCC 15597). To isolate coliphages from sediments, a modified method to isolate human viruses from sediments was used. Preliminary results suggest that coliphages can only be isolated from sewagecontaminated water and sediments. Indicator bacteria were isolated from all samples. Thus, the use of the coliphage test is recommended as an effective and viable means of determining the microbiological quality of water.  ?(  14 Name of Presenter: Timothy Minus Institution: Florida A&M University Classification: Freshman Major Area of Study: Chemical Engineering NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Ralph W. Turner  ?0  Superconductivity and the MeissnerOschenfeld Effect In 1908 Kammerlingh Onnes made a discovery which would greatly alter the scientific world. He investigated the effect such low temperatures, below 4.2K, would have on the electrical resistance of conductors. His data and observations prompted him to describe what he witnessed as an incredible state of superconductivity. As a result of Onnes' ingenuity, others performed their own experiments, further expanding the field of superconductivity. Meissner and Oschenfeld conducted their own research and, in 1933, revolutionized the physicist's attitude toward superconductivity. Their discovery, the Meissner Effect, has resulted in the development and engineering of several future projects. Experiments were conducted at FAMU to test the properties of a superconductor and the Meissner Effect. Data were recorded under variable conditions to ensure the validity and accuracy of the experimental procedure. These results validate that superconductivity has the potential of exerting a profound effect on society. 15 Name of Presenter: Jerri Moore Institution: Florida A&M University Classification: Freshman Major Area of Study: Mathematics NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Ralph Turner The Definition and Some Fundamental Applications of the Number "e" The number e (2.71828...) is perhaps the second most prominent number in mathematics, but the contention is hereby made that the typical student does not have a clear conception of what the number+,,,, "e" really is. If a high school or college student of mathematics were to ask "what is e", it will not be unusual to hear such answers as the following: (a) it is the base of the natural logorithm (b) it is approximately 2.718 (c) it is a rational number (d) it is a transcendental number (e) it is used in calculus (f) it is a number like pi or the square root of two. While all of these responses are not absolutely incorrect they are not correct either, and definitely are not to be used as a definition. The purpose of my presentation is to define the number "e" and provide important applications of "e". 16 Name of Presenter: Rene Reyna Institution: San Antonio High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Richard Howe Operational Test Program This research project addresses the concern of the United States Air Force in simplifying maintenance of the integrated avionics systems, subsystems, and sensors on the A-10 aircraft. In this project the Operational Test Program (OTP) software is being tested to provide troubleshooting and diagnostic capabilities to simplify maintenance. OTP will utilize existing Built-in-Text (BIT) software and communication interfaces aboard the A-10 aircraft. The OTP software program uses fault codes generated by the A-10's LASTE computer to help maintenance crews correct problems with step-by-step series of tests that determine where a failure has occurred and what corrective action needs to be taken. Diagrams derived from fault codes generated by the A-10's LASTE computer are analyzed to determine hardware failures. The research team consists of the Avionics and Support Systems of Southwest Research Institute, who will write and develop the Operation Test Program software, and McClellan Air Force Base, who will provide aircraft where testing of the software can be performed. The Operation Test Program software will help simplify maintenance and reduce repair time of the A-10 aircraft. The technology from this project is directly applicable to other aircrafts. 17 Name of Presenter: Melanie Sandoval Institution: Two Eagle River School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: David Rockwell Snag Survey on the Jette Special Management Area *-,,,ԌOld growth forest is a critical part of the habitat for many sensitive animal species. This type of forest is becoming increasingly scarce due to conflicts with human activities. Our purpose is conducting this study was to show the effects of logging on snag dependent avifauna. The study has been divided into two sections. In the first, data was collected on the number and quality of snags in our study area that were being used by avifauna. The second part of the study, which will be conducted in the fall, will consist of collecting information on how many snags were retained during logging, and how logging has affected populations of snag dependent species in the area.  ?(  18 Name of Presenter: Melody Sims Institution: Beaumont High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dannette ConnorWard A Study of Chromosome Breakage in Soybean Using the Root Tip Squash Technique Food production is a major area of concern for environmentalists, agriculturalists and other scientists who study manmade and natural effects on land arability. One reason often cited for the weakening of crops and lowered crop production is chromosome breakage. The purpose of this study is to determine the course of chromosome breakage in the past, mutations in soybean were discovered, but the causes not the conditions which produced the causes were documented. It is hypothesized that through the Root Tip Squash Technique, the maximum allowable dosages of ultraviolet and gamma irradiation to the soybean plant can be determined. Soybean root tips were exposed to ultraviolet and gamma radiations in varying wavelengths and times. These root tips were examined, using the Phase Contrast Microscope, to determine the frequency and the degree of chromosome breakage. 19 Name of Presenter: Hilda M. Sol Soto Institution: University of Puerto RicoRio Piedras Classification: Freshman Major Area of Study: Biochemistry NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Osvaldo Rosario Evaluation of the Residue Level of Pesticides in Imported and Local Xanthosoma Sagittifolium Pesticides are chemicals used to eradicate pest. In this investigation, an analytical evaluation of the residue levels of pesticides in imported and local Xanthosoma sagittifolium (tanier) was performed. There exists the possibility that some vegetables may contain dangerous residue levels of pesticides. Furthermore, the*.,,, pesticide may react within the vegetable, soil or water and form secondary compounds. The FDA method was modified to shorten time and to analyze a broader range of compounds. The method was evaluated using different solvents; the better being a mixture of Hexane and Dichloromethane (1:1). The sensitivity of the analysis by gas chromatography mass spectrometry was determined and found to be  C@ 10é9 grams of residue. A series of compounds were found in common in the taniers analyzed. Among the compounds were phthalates isomers (common in plastic) and terpenes (aromatic compounds). Two sterol isomers and vitamin E were also found. Preliminary analyses performed did not demonstrate the presence of chlorinated pesticides. Other families of pesticides will also be sought. There are plans to determine the possible presence of pesticides on the tanier surface. Nutritional value studies will also be performed. 20 Name of Presenter: Jennifer Tabullo Institution: Socorro High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Sandra Reinhardt Potable Water Potable water, or drinking water, is the basis of all life on earth. It is a mixture of contaminants that can be both helpful and harmful to humans. Fortunately, there are devices available to help improve the quality of water. A number of diseases have been associated with potable water, such as cancer, respiratory disease, and Alzheimer's disease. Potable water has been known to cause defects in reproduction and child birth. The contaminants found in potable water vary greatly in amount and type. Lead, arsenic, copper, and mercury are heavy metal pollutants present in water. Chemical contaminants such as chlorine, fluoride, iron, and nitrates are added to help improve the water for human consumption. Devices known as filters improve water quality by removing impurities. There are several types of filters, classified according to the filter media and direction of flow. There are other devices that also help to improve water quality. Distillers and GAC filters are two examples. These units are specifically made for home use and come in several shapes and sizes.  ?L&  21 Name of Presenter: Bridgette Taylor Institution: Beaumont High School NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. James Hunsley */,,,Ԍ ?  A Comparison of the Growth Rate of Seedlings Treated and Untreated with Allelochemicals Some plants become predominant in both cultivated and natural settings. One reason for this predominance is the presence of allelochemicals, chemical inhibitors that give plants more strength and also adversely affect other plants in the immediate surroundings. The purpose of this study was to compare the effectiveness of the allelochemicals in three plants (oak, pine, and walnut trees) in enhancing the growth of allelochemically treated plants: corn, soybean, and rice. The hypothesis was that those treated with allelochemicals demonstrate a higher growth rate than those untreated. For two weeks, the corn, soybean, and rice plant growths were measured every two days. The growth of the corn plants treated with oak, pine, and walnut extracts measured 3.7 mm, 6.28 mm, and 8.43 mm, respectively. The soybean was the control. The rice plants measured 4.74 mm growth using oak extract, zero growth using pine extract, and 11.2 mm using walnut extract. Results show that the plants treated with allelochemicals extracts from the walnut tree demonstrate the highest growth rate, followed by the oak and pine trees, respectively.  ?  22 Name of Presenter: Rafael Marcos Villegas Institution: University of Pennsylvania Classification: Sophomore Major Area of Study: Electrical Engineering NSF Sponsoring Program: CRCM Faculty Advisor or Mentor: Dr. Jan van der Spiegel Data Transfer Interface Design The project consists of designing and building a fast data transfer interface for an IBM compatible and a Neural Computer. The interface uses DMA from the computer to its own interior 4K byte buffer. It will be able to transfer data out serially at rates as high as 6 million bits per second. The interface will have different modes of operation: 1) DMA parallel transfer from the computer to internal buffer, 2) Serial data out from internal buffer to neural computer, 3) Data in and data out serially and simultaneously, 4) Parallel data out for computer to read internal buffer. `"0,,, UNDERGRADUATE PROGRAMS ALLIANCES FOR MINORITY PARTICIPATION (AMP) RESEARCH CAREERS FOR MINORITY SCHOLARS (RCMS) 1,,, ALLIANCES FOR MINORITY PARTICIPATION (AMP)  ?X  23 Name of Presenter: Juan M. Acosta Institution: University of California, Irvine Classification: Senior Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. L. Dennis Smith  ?` Regulation of the Cell Cycle in Xenopus Laevis Oocytes Xenopus laevis oocytes are arrested in prophase of meiosis one, however various agents are able to trigger the progression to a second arrest at metaphase of meiosis two. The project consists of bathing or injecting into Xenopus oocytes various agents known to affect the cell cycle. During the school year I worked with GTP s, a Gprotein activator; cmos mRNA; and RAS mRNA. Both mRNAs result in the production of a large quantity of the respective protein in the oocyte and trigger cell cycle progression. During the summer I will begin a new study using agents known to affect the cell cycle in other organisms, but whose affect on Xenopus oocytes is unknown. My results and conclusions will be presented at lab meetings for general discussion and suggestions.  ?  24 Name of Presenter: Carl Allen Institution: University of California, Los Angeles Classification: Junior Major Area of Study: Biochemistry NSF Sponsored Program: AMP Faculty Advisor: M. Frederick Hawthorne Novel Functionalized Macrocyclic Chelates for Radioimmunolmaging  ? and Radioimmunotherapy of Cancer  Scientists have been searching for cures for the disease of cancer for well over twenty years. Many of the advances in the diagnosis and treatment of cancer have relied on the use of radioactive metals. Our research is concerned with the synthesis of novel functionalized macrocyclic compounds with the ability to efficiently bind radiometals of interest. The functional groups attached to these chelators allow them to be conjugated to tumor selective antibodies for use in radioimmunolmaging and/or radioimmunotherapy. Specifically, we are concentrating on the synthesis of monofunctional derivatives of DOTA, a macrocycle chelator that is useful with several radiometals (especially yttrium). As such, we have synthesized a triprotected DOTA derivative and are currently exploring its monoalkylation, and routes to hydrazide derivatives of DOTA, which should be useful for antibody conjugation through the carbohydrate region. +2,,,Ԍ ? ԙ 25  ?  Name of Presenter: Ayde Aparicio Institution: University of California, Irvine Classification: Senior Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Eloy Rodriguez  ? Naturally Occurring Allergens that Cleave DNA Previous investigations on environmental toxins and dietary constituents have shown that some of the chemicals that we ingest or come in contact with possess the capacity to cleave DNA. We have examined sesquiterpene lactones, known to cause contact dermatitis, for their ability to damage DNA. In vitro DNA cleavage assays have demonstrated that sesquiterpene lactones possess the capacity to cleave DNA to various degrees. Furthermore, from these preliminary findings we suggest that sesquiterpene lactones form free radicals as possible intermediates in the cleavage of DNA. 26 Name of Presenter: Shirleceia Archie Institution: Stillman College Classification: Junior Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. James McClintock The Effects of CopperNitrate on the Growth, Food Consumption, Egg Mass Deposition and Embryogenesis of the Pulmonate Gastropod Physella Cubensis Copper levels in freshwater systems of Alabama can reach levels which are potentially toxic to aquatic organisms. We investigated both acute and chronic effects of coppernitrate on a common pulmonate gastropod which occurs in both ephemeral ponds and low velocity stream habitats of northcentral Alabama. Embryos, juveniles and adults were exposed to water containing four concentrations of coppernitrate (0.5, 0.1. 0.05 and 0.01 mg/l). Complete mortality occurred within 3 days for adult gastropods exposed to the two highest concentrations. Adults exposed to 0.05 mg/l suffered 79% mortality over a 36 day period. Control individuals and gastropods held at the lowest copper levels suffered reduced mortality (4051%) over a similar period. Adult gastropods exposed to 0.05 and 0.01 mg/l grew less than did control gastropods. Juveniles exposed to the lowest concentration (0.01 mg/l) grew at a rate similar to controls. Adults held at 0.05 mg/l ingested significantly less artificial food than did individuals held at 0.01 mg/l or controls. Adult gastropods exposed to the two highest copper levels did not produce any egg masses. Adults exposed to 0.05 mg/l produced only half as many egg masses as did individuals held at 0.01 mg/l of controls. Moreover, the number of eggs per egg mass were significantly reduced in both groups of gastropods exposed to copper. Embryonic egg masses introduced to+3,,, water containing different concentrations of coppernitrate showed dramatic embryological effects. Embryos exposed to 0.5 did not develop to the gastrula stage, while individuals exposed to 0.1 mg/l did not develop beyond gastrulas. Results from individuals held at 0.01 mg/l and controls hatched from egg masses indicate that coppernitrate can have both acute and chronic effects on the lifehistory of the gastropod Physella cubensis. This organism is therefore an excellent model as a bioindicator of aquatic pollution.  ?  27 Name of Presenter: Leonel Arellano Institution: University of California, Irvine Classification: Junior Major Area of Study: Mechanical Engineering NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Professor G. Scott Samuelsen/Ted Fastes  ?  Combustion Instability in Liquid Propellant Rockets Drop Breaking  ?h as a Possible Mechanism  ?  A number of researchers have identified propellant drop breakout as a possible mechanism for combustion instabilities in liquid propellant rockets. During this past summer, I assisted in research being conducted to investigate drop breakup ("secondary atomization") under simulated rocket engine conditions via a shock tube. It is desirable to understand what role the interaction of a shock wave and fuel/oxidizer droplets has during combustion instabilities. Combustion instabilities in liquid rocket engines can be catastrophic since high frequency acoustic combustion instabilities can result in severe hardware damage. High amplitude pressure waves can cause structural failure, and high heat transfer rates can cause excessive erosion of the combustion chamber walls. In the experiments performed, the interaction between a shock wave and drops of fluids is photographically observed and analyzed. It has been observed that a shock wave can cause propellant drops to shatter into smaller drops, thus increasing their evaporation and mixing rates. By increasing these rates, the reaction rate and subsequent heat release may also increase. Furthermore, it is suspected that proper phasing behavior of heat release and the pressure wave can cause resonant behavior and thus combustion instability. Attempts to minimize the effects of combustion instabilities by altering the design of the injectors, chamber walls, and nozzle have been made. However, they simply tend to reduce performance of the rocket and increase costs. Thorough understanding of drop breakup may offer innovative ways of inhibiting combustion instabilities.  ?+  28 +4,,,ԌName of Presenter: Ramiro Bouroncle Institution: University of Utah Classification: Senior Major Area of Study: Mechanical Engineering NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Joseph C. Klewicki Sonic Anemometer Flow Blockage Effects The focus of this study is on the technique used to develop an accurate test procedure for measuring and predicting fluctuations in wind velocities in a fully turbulent atmosphere. For this purpose, it is common practice to use a sonic anemometer. A sonic anemometer measures wind velocity via a local measurement of the speed of sound. From past research it has become apparent that flow blockage effects caused by the anemometer can result in significant measurement errors. The goal of this study is to quantify these errors. For the purpose of devising correction schemes, the experiments are performed in a wind tunnel fitted with a steel grid located upstream the sonic anemometer. The purpose of the grid is to generate turbulence similar to that found in the atmosphere. A flow visualization system is used to qualitatively study the transducer wakes. Previous data indicates that the wake velocity deficits can be physically meaningful to the understanding and comparing of the wind tunnel results to absolute measurement capabilities in the atmosphere. Both qualitative flow visualization and quantitative flow visualization hot-wire data will be presented. 29  ?  Name of Presenter: Roderick F. Burgess Institution: Alcorn State University Classification: Senior Major Area of Study: Medical Technology NSF Sponsored Program: AMP Faculty Advisor or Mentor: Dr. Troy Stewart The Effect of Filtered Cigarette Smoke on Elastase Activity in Hamsters Frequent exposure to cigarette smoke leads to excessive inflammation which can create pathological conditions such as those seen in many chronic diseases that affect the lungs. The main purpose of this experiment is to investigate the mechanism responsible for the enhancement of protease activity by cigarette smoke. Elastase activity was detected in hamsters exposed to cigarette smoke. Experimental groups were placed in a noseonly exposure chamber and exposed to cigarette smoke for two seconds alternated by thirty seconds of oxygen for a total of eight minutes per exposure period. Exposure period was twice a day for two weeks. The control animals were mock exposed. After exposure, macrophages and neurophils were recovered from the hamsters. Elastase activities were determined by using a modifica+5,,,Ԯtion of the microassay method. This method permitted immediate measurement of the enzyme substrate mixture and helped clarify the effects of cigarette smoke on the proteinaseantiproteinase balance in the lungs. Results showed that elastase activity appeared to be greatly enhanced when the hampsters were exposed to the cigarette smoke. 30  ?  Name of Presenter: Khalid Channell Institution: University of California, Irvine Classification: Senior Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Joseph L. Graves Laboratory Selection and Life History Traits in Drosophila arizonesis This study examines the patterns of life history evolution in Drosophila arizonensis established in the laboratory on an early reproduction schedule. Evolutionary theory suggests that the response of longevity and fecundity to selection for early reproduction should result in a decrease in the former and an increase in the later. D. arizonensis is a desert species in which selection in the natural environment is expected to involve resistance to desiccation, organic volatiles in cactus, starvation, and extended flight duration. These physiological variables have been shown to increase life span and decrease early fecundity in D. melanogaster. Assays of longevity and fecundity will be carried out every other generation to see if selection for early reproduction causes the predicted decline in longevity predicted by the antagonistic pleitropy hypothesis for the evolution of life history characters.  ?  31 Name of Presenter: Jessica Gaspar Concepci;n Institution: University of Puerto RicoSan Juan Classification: Sophomore Major Area of Study: Zoology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Jos) Garc1a Arrars Study of the EntericNervous System of the Sea Cucumber Holothuria  ?% glaberrima During the Different Stages of Regeneration. The study of the regeneration of the nervous cells in invertebrates is very important because its possible application of the results to vertebrates, specially to humans. In the previous stage of this investigation, it was demonstrated that the regenerated enteric nervous system of the sea cucumber Holothuriaglaberrima contains cells and nerve fibers that express the neuropeptides cholecystokinin and FMRF in the same way as in the original tissue. The+6,,, purpose of this second phase of the study is to identify the expression of the cholecystokinin and FMRF in the enteric nervous system of the sea cucumber Holothuriaglaberrima in the different stages of regeneration. In order to achieve this objective, the immunohistochemistry technique, which makes use of antibodies to detect the presence of cells and fibers that express substances in the tissue, was used. The results demonstrate that in tissue of six days of regeneration there is nerve fibers in the mesentery and the blastule that expresses cholecystokinin and FMRF. In tissue of twelve days of regeneration, it was observed that there was expression of cholecystokinin and FMRF in nerve fibers of the external connective tissue and the internal connective tissue. But there was more labelling of both neuropeptides in nervous fibers at the internal connective tissue. There was also expression of both neuropeptides in cells of the external connective tissue. We can conclude that there is an increase in complexity of the enteric.  ?  32 Name of Presenter: Rub)n Le;n Cruz Institution: University of Puerto Rico Classification: Sophomore Major Area of Study: Mathematics NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Prof. Italo J. Dejter, Pedro Rivera Vega  ? Decomposition of Complete Graphs into Isomorphic Cycles Decompositions of Complete Graphs (DCG's) into Isomorphic Cycles is a topic of great importance in the area of Combinatorial Designs, as it is a source of Balanced Incomplete Block Designs with special conditions. Their production and enumeration have some computational intricacies that we are studying. Computational techniques are being used, mainly, invariants determination, backtracking and orderly algorithms. In particular, we aim to the determination and enumeration of all DCG's of order <= 9 into uniform cycles. PASCAL programming and implementation of the diverse tasks related with  Cx the determination of O(n2) invariants, backtracking techniques and orderly algorithms, as well is the interpretation of adequate algorithms in the references are the methods used in this research.  C We obtained until this point, the determination of the O(n2) invariants under our focus for all 122 Hamiltonian Decompositions of K(9) and 6cycle decompositions of K(9). It seems possible to complete to a reasonable point a catalogue of DCG's into isomorphic cycles.  ?P&  33 Name of Presenter: Jerome E. Davis Institution: University of California, Irvine  < Classification: Senior Major Area of Study: Aerospace Engineering NSF Sponsoring Program: AMP+7,,,ԌFaculty Advisor or Mentor: Dr. Gregory L. Long  ? Telerobotic Hand Controller for Hazardous Waste Removal The broad purpose of this project is to design a robot which can detect and remove hazardous waste while allowing the operator to remain at a safe distance. Sophisticated force sensing capabilities will be incorporated into the robotic system so that objects which are being moved will not be dropped or crushed. Motors fixed to the base plate of the joystick will coordinate the movement of the robotic hand. Feedback via force sensors on the robotic hand will be sent back to a computer where an algorithm will be used to simulate the force and send signals to the motors for repositioning. This signal produces a response which is felt by the controller through the joystick. The operator then knows how much pressure is being exerted by the robotic hand and can adjust input accordingly. Expected time of completion is early September, 1992.  ?  34  ?h  Name of Presenter: Vanessa D1az Institution: University of Puerto RicoSan Juan Classification: Senior Major Area of Study: Biology NSF Sponsoring Program: PR/AMP Faculty Advisor or Mentor: Dr. Sharon File  ? Mast Cells in Schistosome Infected Rodents Mast cells produce and hoard cytoplasmic granules, containing histamine and heparin. It had been reported that adult schistosomes release a material that inhibited or reduced mast cell degranulation. The purpose of this study was to explore this hypothesis by quantifying mast cells in the ileum of animals harboring adult schistosomes in the adjacent veins. If worms inhibit degranulation, then granulated mast cells should accumulate in the presence of worms. The ileum of normal, unisexual and bisexually infected hamsters (Mesocricetus auratus) with 68 week old S. mansoni infections were fixed in Carnoy's and stained in Giemsa. The mast cells were counted and expressed as cells/mm. The mean number of mast cells in normal hamsters was 13.2 cells/mm; in unisexual infections the mean was 45% less and in bisexual infections there were 260% more most cells (X=34.3 cells/mm) than in uninfected animals. The marked accumulation of mast cells suggests that further studies on the role of the mast cell in this parasitic infection would be valuable.  ?H&  35 Name of Presenter: Cynthia Doyle Institution: Prairie View A&M University Classification: Junior Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Verlie Tisdale+8,,,Ԍ ?  ÙProtein and Antigen Profiles of Corynebacterium Pseudotuberculosis Caseous lymphadenitis (CLA), in sheep and goats is caused by Corynebacterium pseudotuberculosis. To understand the immune response to infection and to develop improved vaccines and diagnostic agents, the nature of the antigens that are involved in the pathogenesis was investigated. Whole cells and culture supernatant of various isolates of Corynebacterium pseudotuberculosis were studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDSPAGE) and Western blotting (immunoblotting). SDSPAGE analysis of detergentsoluble whole cells revealed more than 30 bands in silverstained gels. SDSPAGE analysis of ammonium sulphate concentrated culture supernatant demonstrated more than seven bands in silverstained gels ranging in molecular mass from 6414KDa. Western blot analysis identified antibodies in the goat sera to ten or more SDSsoluble proteins from whole cells, ranging in molecular mass from 14119KDa. These sera also recognized up to five molecules ranging form 3065KDa, on immunoblots of ammonium sulfate concentrated culture supernatant. The results from this study identifies the detergent soluble antigens in whole cells and culture supernatants that are recognized by sera from naturally infected and diseased goats. (USDA/ARS 91341365902)  ?P  36 Name of Presenter: Robert Falcon Institution: Houston Community College Classification: Freshman Major Area of Study: Liberal Arts/PreEngineering NSF Sponsored Program: AMP Faculty Advisor: Ms. Diana Castillo  ?X Analyzing Protein and Sequenced DNA My research experience began at Baylor College of Medicine in the Cell Biology Department and the Radiotherapy Department. I was a lab assistant in Cell Biology studying oogenesis, particularly the reactions that take place when the sperm enters the ovum. My role in these studies consisted of analyzing protein and sequenced DNA, removed from ovaries, on a computer. I currently work in a Radiotherapy clinic fabricating shield block and face and neck immobilizers. The shield blocks are used between a radiation source and the patient to shadow areas not requiring irradiation. A physician and I conducted an experiment to find the amount of radiation that penetrates through different thicknesses of the shield block. We discovered that the original thickness used, two inches, was not suitable for treatment. I hope that these experiences at Baylor College of Medicine will help me obtain a career in chemical engineering.  ?+  37+9,,,Ԍ ?  ęName of Presenter: Gary P. Fontan Institution: University of California at Irvine Classification: Senior Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Eloy Rodriguez Induction of Reactive Oxygen Species by Falcarinol in the Presence of a Mixed Function Oxidase Inhibitor in Rat Subcellular Fractions Polyacetylenes are common natural products in spices, plant medicines, and ingested vegetables, such as ginseng, parsnip, skirret, parsley, carrot, and celery. A major polyacetylenic constituent of celery (Apium graveolens) and ginseng (Panax ginseng) is the potent human contact allergen, falcarinol. The polyacetylene falcarinol has also been implicated as a neurotoxic agent. Studies using 2', 7'dichlorofluorescin diacetate (DCFHDA) were undertaken to explore the neurotoxicological properties of falcarinol and its possible mechanism of action. DCFHDA is rapidly oxidized to the highly fluorescent 2'7'dichlorofluorescein by Reactive Oxygen Species (ROS) such as superoxide anion and hydroxyl radicals. Falcarinol induced the formation of active oxygen species in both liver and brain fractions in a dosedependent manner. The generation of ROS by falcarinol was increased by the presence of SKF525A, a mixed function oxidase inhibitor, in the liver while a decrease was observed in the brain.  ?  38 Name of Presenter: Rachel Garcia Institution: New Mexico State University Classification: Senior Major Area of Study: Biochemistry NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Bernard McNamara  ? The Search for the Origin of Cosmic Gamma-Ray Bursts Since 1972 over 900 cosmic gamma-ray bursts have been detected by various spacecraft. The study of these bursts is a major mission of the recently launched Compton Gamma-Ray Observatory. Since the positions of the bursts are only approximately known, none have been optically identified. Their origin remains a mystery. This project examined two hypotheses concerning the locations for the gamma-ray bursts, (1) that they are located within a few hundred parsecs of the Sun, or (2) that they are located at cosmological distances. The first hypothesis was investigated by searching small gamma-ray error boxes for large proper motion objects. The second hypothesis was tested by examining Palomar Sky Survey prints for external galaxies. Our preliminary result showed that some large proper motion objects are presented in the gamma-ray error boxes. These objects will form a list of candidates for further study.  ?+  39+:,,,Ԍ ?  ęName of Presenter: Eric Gonzales Institution: Bee County College Classification: Sophomore Major Area of Study: Science NSF Sponsored Program: AMP Faculty Advisor: Dr. Ken Stevenson Roles of Student and Faculty Interaction in Promoting Science,  ?@ Engineering and Mathematics The student/faculty interaction when making joint presentations related to science, engineering and mathematics is effective in promoting positive attitudes in an audience of prospective students by creating an excitement rather than a phobia based on formulas and equations. Experiments integrating both mathematics and science in a joint teaching effort by student and faculty show cooperation which is seen by prospective students as fostering a comfortable learning relationship. The cooperation between student and faculty encourages promising yet tentative students to rise to their potential and to meet the academic challenges in the fields of science and math. Student and faculty joint presentations in the classroom and laboratory can result in a significant increase in the number of student majoring in science, engineering and mathematics.  ?  40 Name of Presenter: Cynthia Granado Institution: University of Arizona Classification: Junior Major Area of Study: Mathematics Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Diane Hermann  ?   Puzzles of the Past Solving Questions of the Future The Frenchman Pierre De Fermat contributed to mathematics in the areas of geometry, calculus, probability, and number theory. In approximately 1635, Fermat wrote in the margin of Diohantus' ARITHMETICA a theorem which he never proved. That is, for n>2, no triple set of positive integers x, y, z exists which satisfy the  C! equation Xn+Yn =Zn. For centuries, Fermat's Last "Theorem" (FLT) has perplexed the mathematical world. Progress has been made in proving FLT, but one set of unproven cases remains. Although many attempts have been made both to prove and disprove this theorem for the general cases, all have fallen short. However, the search for a solution continues to produce many discoveries about the relationships between numbers. As a result of this research, various new fields of mathematics have arisen which play a central role in modern mathematics.  ?4*  41 *;,,,ԌName of Presenter: Audray K. Harris Institution: Tougaloo College Classification: Sophomore Major Area of Study: Chemistry NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Wayne J. Brouilette and Milton L. Brown Synthesis and Resolution of Diphenylhydantoin Analogs with Enhanced  ?@ Lipophilicity Recent data from our laboratory has demonstrated for the first time that the diphenylhydantoin (DPH) binding site on the neuronal voltage sensitive sodium channel may be stereoselective. To further investigate stereoselectivity at the DPH binding site, separation of the enantiomers for previously reported racemic hydantoin analogs is required. In this study chiral HPLC was investigated as a preparative method for separating the enantiomers of 1, 2 and 3. Thus different solvent systems and chiral stationary phases were evaluated in order to optimize the separations. Racemic hydantoins 4 and 5 were synthesized from the appropriate ketone using BuchererBergs procedure. The log P values for these compounds were determined using a computational method. The in  C vitro IC50 values for the inhibition of the binding of tritiated  CT batrachotoxinin A 29benzoate ([3H] BTXb) to rat cerebral cortex synaptoneurosomes was also determined. The results suggest a correlation between log P and sodium channel binding.  ?@  42 Name of Presenter: Denise Hooks Institution: Jackson State University Classification: Senior Major Area of Study: Chemistry NSF Sponsored Program: AMP Faculty Advisor or Mentor: Dr. Eric A. Noe Conformational Equilibria for Thiolformate Esters and NSubstituted  ? Formamides Populations of E and Z conformations were obtained at room temperature by carbon NMR for dilute solutions of Nsubstituted formamides, and thiolformate esters were studied at low temperatures by proton or carbon NMR. The results provide evidence for the importance of "aromaticity" in stabilizing the Z conformations of most esters, secondary amides, and related compounds. For example, the low population of the E conformation of methyl thiolformate in deuterated dichloromethane (1.6%) contrasts with the population of 52.5% for this conformation of thiolformic acid reported by other workers. The enhanced population of the Z isomer of the methyl thioester is attributed to stabilization by a cyclic system of six electrons, with two each contributed by the carbonyl group, the sulfur, and a pitype orbital of the methyl group. +<,,, Evidence will be presented that cyclopropy, vinyl, and phenyl groups, unlike methyl, do not complete an aromatic sextet. Barriers will also be reported for the thioesters. 43  ?  Name of Presenter: Kimberly L. Jackson Institution: Tougaloo College Classification: Sophomore Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Joseph J. Gauthier Water Recycle System for a Space Station Space Station Freedom (SSF) is essential for future exploration of space. NASA is currently developing a water recycle system for the Space Station to provide water for the crew during missions of 90 180 days duration. The potential health hazards associated with closedloop water treatment systems are a major area of concern. In our laboratory, we are participating in microbiological studies of the water recycling system to assure its safety. Endotoxins, which are lipopolysaccharides residing on the surface of Gram negative bacterial cells, are responsible for toxic shock, fevers, chills, and immune system problems in humans and animals. Experiments performed by other investigators using water from various recycling treatment systems, demonstrated the presence of endotoxin in treated water. A significant buildup in the concentration of endotoxin could develop as the result of longterm recycling of water in the treatment system. In this study, we demonstrated that the level of endotoxin in combined wastewater from Stage 8 of the Water Recovery Test being conducted by NASA and Boeing, Inc. was significantly reduced by current methods of treatment. 44 Name of Presenter: Curtis Johnson Institution: Mississippi State University Classification: Senior Major Area of Study: Mechanical Engineering NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Charles Wilcox The Mechanism of Hydroboration. An Ab Initio Study of the Reaction of Ethylene with Boranes Ab initio calculations at the 6-31G* level yield excellent equilibrium energies for non-polar reactions (like synthetically important hydroboration reaction). Less favorable results are obtained for the energies and transition states connecting the equilibrium states, but inclusion of the Moller-Plesset corrections during the geometry optimizations seems to improve the results greatly. The student will expand upon the 6-31G* optimizations +=,,,Ԍfor the hydroboration reaction to include MP2/6-31G*, MP3/6-31G*, and MP4/6-31G* optimizations and to determine the minimum level of Moller-Plesset theory required to achieve convergent energies. 45 Name of Presenter: Sharon Lay Institution: University of Mississippi Classification: Sophomore Major Area of Study: Electrical Engineering NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Richard Sullivan Fiber Optics and Splicing Techniques Fiber optics has been a new industry developed to replace copper and its limitations in telecommunications. The optical fiber is a purely glass element surrounded by a polymeric coating and glass cladding. The optical fiber is approximately the size of a human hair. The optical fiber can transmit signals over 35 miles without a regenerator. Also, it can transmit 2.5 gigabits per second or over 32,000 voice conversations simultaneously. The advantages of fiber optics vary from bandwidth and loss to crosstalk and security. The challenge for the future with fiber optics is to increase both capacity and distance without regenerators. This can be accomplished by new and better types of fiber and fiber splicing techniques. These current developments in splicing techniques will be discussed. 46 Name of Presenter: Renee Lee Institution: Jackson State University Classification: Junior Major Area of Study: Chemistry NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. David Smith Determination of Sites at Which Acid Proteases Cleave Bovine Lens A-crystallin  Conformational changes in the protein structure that accompany cataracts are being studied by the rate at which amide hydrogens in lens proteins exchange with deuterium. The investigation depends upon the ability of lens proteins to fragment into peptides which can be tested by fast atom bombardment mass spectrometry (FABMS). Pepsin is now being used for this purpose. The current project tests optional acid proteases for use in fragmentation of lens proteins. The lens protein was digested with 1.5 concentrations of acid proteases from 3'3'StandardrJet IIISi (Addi3'3'StandardrJet IIISi (Addi(ѰX%> Aspergillus saitoi and Rhizopus chinesis bacterias for four hours at 37 degrees Celsius. The protease solution was prepared with a pH 2.7 solution of HPO4/H2PO4 buffer. Separation and purification of the fragments upon digestion were carried out by reversed-phase high performance liquid chromatography (HPLC). The peptides were then analyzed by a KRATOS MS 50+>,,, FABMS. Results were evaluated by computer-assisted analysis which matched a molecular weight with all possible fragments for that particular weight and the hydrophobicity of each possibility. From the literature we proposed specific cleavage points for each protease. Inferences were made upon the cleavage point of the fragment possibilities, their hydrophobicities, and the retention time of the samples in the HPLC column. Several fragments met these criteria and are believed to be true peptides of alpha A crystallin. Further testing may be done by mass spectrometry to confirm these assignments. Studies of varying fragmentation patterns of other acid proteases may aid in future cataract research.  ?  47 Name of Presenter: Ericka N. Lock Institution: University of California, Irvine Classification: Senior Major Area of Study: Computer Science NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Prof. Richard Selby A Perspective of Distributed Systems Networking A distributed computing system consists of multiple autonomous processors, possibly of different architecture which are interconnected by a communication subnet to interact in a cooperative way to achieve an overall goal. To achieve this goal the systems are logically integrated by a distributed operating system and/or a distributed application like a distributed database system. The most commonly used paradigm in constructing distributed applications is the client/server model. In this scheme, a server is a process that is waiting to be contacted by a client process so that the server can provide services to the client. For example, in a database system, there is a process that is waiting for a request to read or write a file for the client. This paper gives an overview of networking, and concentrates on the client server paradigm. Moreover, it looks closely at the interactions between client and server applications considering different interprocess communication mechanisms (IPC). The intent of this study is to understand the concepts of networking and the standard model for network applications. I am currently developing a prototype that supports the Amadeus measurementdriven analysis and feedback system in a distributed environment. The prototype will enable Amadeus to support largescale software development teams and processes in distributed locations.  ?(  48 Name of Presenter: Tamara M. Long Institution: University of Arizona Classification: Sophomore+?,,,ԌMajor Area of Study: Civil Engineering NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Steven J. Wright  ? Parshall Flume Recalibration at Low Discharges Accuracy is an important and desirable characteristic of measuring devices currently in use. The Parshall flume is a device which uses a unique depth-discharge relation at a measurement section to predict the flow of water. Generated from data collected in 1936, Ralph L. Parshall developed rating equations to predict the performance of different sized flumes. Recent studies (Wright & Taheri) have shown these flumes are currently being recommended for use at low discharges for which data was not originally collected and using Parshall rating equations at low discharges can overpredict the flow by as much as twenty-five percent. The purpose of this project is to recalibrate these flumes for accurate measurement at low discharges. Data were obtained at low discharges for flumes of various sizes which were used to generate alternate equations. A computer model which predicted the flow depth at the measurement section was developed by a Ph.D. student also involved with this project. The results obtained by the computer model sufficiently agreed with the experimental data obtained. 49 Name of Presenter: Daniel Maga9a Institution: University of California, Davis Classification: Senior Major Area of Study: Biological Sciences NSF Sponsored Program: AMP Faculty Advisor: Dr. Satya Danoekar Immunohistochemical Identification to Cell Markers in SIV Infected Gastrointestinal Tissue of Rhesus Macaques The gastrointestinal tract is a major target for HIV/SIV infection. We have used SIVinfected rhesus macaques as an animal model to investigate cell markers in HIV infection. The major objective is to identify T lymphocytes, macrophages, and proliferating epithelial cells in SIV infected rhesus macaques. To identify proliferating and infiltrating cells, immunohistochemistry was performed on formalinfixed, paraffinembedded and cryostat jejunal tissue sections. Stained tissue sections clearly displayed proliferating epithelial cells and immune responsive cells. Having successfully identified these markers it is possible to follow longitudinal changes in these cells as SIV infections progress. 50 Name of Presenter: Araceli Martinez Institution: Texas A&I University Classification: Senior Major Area of Study: Chemical Engineering +@,,,ԌNSF Sponsored Program: AMP Faculty Advisor: Jorja Kimball The Junior CollegeUniversity Transition When first enrolled in college, I had not decided where I planned to complete my studies. I did, however, intend to study at least one year in college, enrolling in the basic coursesMath, English, Science, and P.E. Afterwards, I planned to transfer to a fouryear university. My major was undecided. For this reason and for economics, I first attended a Junior College instead of a University. Three common transition problems are as follows. First, there is a communication gap between the College and University. Information on scholarship and admission is sometimes old, limited, or unavailable at the college. Second, there is a conflict of "priorities". College counselors, "suggest" that students enroll in courses leading toward an associate degree. Not all have this goal in mind. Another problem in transferring is lost of credit hours. If I had not concentrated on obtaining an Associate Degree, I would have lost fewer hours. 51 Name of Presenter: Manyalibo Matthews Institution: University of California, Davis Classification: Senior Major Area of Study: Applied Physics NSF Sponsored Program: AMP Faculty Advisor: Drs. Philip Yeger and Morris Pripskin Hadronic and Electronic Energy Loss in Warm Liquid Calorimetry Energy spectra of a 5225 GeV meson beam was examined through online analysis of particle shower developments in a Tetramethyl Pentane (TMP) type Warm Liquid Calorimeter. The beam profile was primarily made up of +pi mesons, +electrons, and mu mesons. Energy measurement is done by way of charge collection of ionized TMP which is created interaction of high energy particles in the warm liquid. The liquid is encased in eight individual stainless steel jackets per plane in a series of 72 planes. Beam showering was enhanced through the placement of Pb plates placed between the TMP planes. The shower development of the hadron/positron beam was also analyzed replacing the Pb plates with stainless steel. 52 Name of Presenter: Sharoon McHellon Institution: Stillman College Classification: Senior Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Ken Marion and Robert Angus +A,,,ԌBenthic Invertebrate Diversity in a Surface MineImpacted Reservoir The biota of Upper Bear Creek Reservoir (UBCR) in northwest Alabama has been adversely affected by runoff from numerous surface mines in the watershed since its impoundment in 1979. As a result, the quality of the recreational fishery is poor and the impact of the 3'3'StandardrJet IIISi (Addi3'3'StandardrJet IIISi (Addi(ѰX>B reservoir on the local economy has been negligible. In recent years TVA has initiated some watershed improvements and has installed compressed air diffusers to reduce stratification. As part of the ongoing effort to assess the effects of these mitigation attempts, benthic invertebrates were sampled from UBCR and three nearby lakes by Ekman dredge. Low overall densities  C` (57.5 organisms/0.25ft2) and a predominance of dipterans (63.8% of all organisms) were found in UBCR, /indicative of an infertile and stressed aquatic environment. However, comparisons to earlier data indicate some improvement in limnological conditions. 53 Name of Presenter: Gustavo Miranda Institution: University of California, Los Angeles Classification: Senior Major Area of Study: Molecular Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Renato J. Aguilera Biochemical Characterization of the Nuclear Proteins Involved in Lymphocyte Antigen Receptor Gene Recombination We have been isolating lymphocytespecific nuclear factors which are involved in the sitespecific recombination process of antigen receptor gene rearrangement. We have expressed a gene which is involved in this recombination process (RAG1) in bacteria in order to further characterize its biochemical function. We have found that the recombinant RAG1 (rRAG1) protein binds strongly to DNA and that it forms unusual DNAprotein complexes. We are in the process of determining the sequence specificity of this proteinDNA interaction and are also attempting to localize the DNAbinding domain within the rRAG1 protein. We have generated a highly specific antirRAG1 antisera and have used it to detect and isolate the native RAG1 protein from preB lymphocyte and thymocyte nuclear extracts. We hope that through the characterization of this and other factors, we will be able to better understand the mechanism of antigen receptor gene rearrangement.  ?$  54 Name of Presenter: Lisa M. Olivier Institution: University of California, Irvine Classification: Senior Major Area of Study: Medicine NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Moyra Smith*B,,,Ԍ ?  ÙThe Development and Analysis of a DNA Library for Human Chromosome  ? 9Q34qtr Utilizing the AluPolymerase Chain Reaction We have utilized the interAlu Polymerase Chain Reaction (PCR) to derive products from two human chromosomal regions. These regions, 9q34 and 16p13, have previously been determined to contain genes for the autosomal dominant genetic disease Tuberous Sclerosis. An AluPCR DNA library for 9q34qter has been established from such PCR products. Experiments have been carried out to distinguish AluPCR products belonging to the 9q34 and 16p13 regions. These products are being used to search for homologous stretches of DNA between the two chromosomal regions, as well as for dinucleotide or trinucleotide repeat elements which may determine genetic variability within regions. 55 Name of Presenter: Carl Palmer, III Institution: Alcorn State University Classification: Senior Major Area of Study: Chemistry NSF Sponsored Program: AMP Faculty Advisor or Mentor: Dr. Kim Searcy The Effects and Changes of Cyclosporine, FK506, and (AZT) Zidovudine in Isolation and Combination with the Blood and Urine  ? Specimens of HIVPositive and AIDS Patients AIDS and HIV, Human Immunodeficiency Virus, are two deadly viruses. HIV is a possible cause for the Acquired Immune Deficiency Syndrome and there is no cure for either virus. While there is no cure for these viruses or the disease they cause, there are many efforts and suggestions for possible cures or suppressants. One suggestion involves the careful analysis of the two most important bodily fluids which filter waste materials and aid in the development of a stronger immune system. Since the blood is the major carrier of the cells that fight off foreign substances, it is a means to measure contamination. Urine, in contrast, serves as a detector of foreign substances in the body. The bodily fluids and individual medications (Cyclosporine, FK506, and AZT) are first isolated then combined with individual variables of each medication thereby supplying suggestion for a cure. The first two drugs seem to be a big hinderance to these viruses affecting the immune system. Their major drawback is causing other infections. The experimental drug call (AZT) Zidovudine in use today, it is not a cure. It only slows down the HIV and does nothing for AIDS. There are known side effects of this drug as well. Research continues; approximately 400 experimental medications are used daily in the fight against the AIDS virus, HIV, and the infections they cause. No single medication can provide a cure. Therefore, the "cocktail" medication of Cyclosporine, FK506, and+C,,, AZT may be a possible ray of hope in combating a virus that is simultaneously as impervious as a wall of steel and as fragile as a thin sheet of ice.  ?  56 Name of Presenter: Ramona Pilliner Institution: Oakwood College Classification: Sophomore Major Area of Study: Biochemistry NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Jimmy W. Mays A Viscometric Study of the Temperature Dependence of the Conforma ? tion of Poly(phenyl methacrylate) The variation of intrinsic viscosity with temperature has been measured for the poly(phenyl methacrylate)/methyl isobutyl ketone system. A conformational transition is detected in the range of about 2532$C depending on molecular weight of the polymer. This transition is tentatively interpreted as involving specific interactions between phenyl substituents.  ?  57 Name of Presenter: Luc1a M. JesCs Santana Institution: University of Puerto RicoSan Juan Classification: Sophomore Major Area of Study: Chemistry NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Xiaotian Gu and Brand R. Weiner Pulsed Laser Photolysislaser Induced Fluorescence Study on  ?X Vibrational Relaxation of SO Radicals The study of vibrational relaxation in gas phase gives direct information about how energy flows during a bimolecular collision. Experimental techniques such as laserinduced fluorescence provide for the excitation of a specific vibrational state and for observation of the population in each specific state as a function of time. Timeresolved laserinduced fluorescence (LIF) spectroscopy was  C(# used to probe SO radicals following the photodissociation of the SO2 molecule in the gas phase at 193 nm. An excimer pumped tunable dye laser was used to interrogate vibrational states of the SO radicals  C% following collision with different gases (Ar, CO2, SO2, CH4, CH3Cl,  CP& O2, N2, He). History of the SO radical was obtained from variation in the intensity of fluorescence produced versus time. From this  C' transient profile we obtained the bimolecular rate constant, KR, which describes a particular relaxation process for the SO radical  ?x) in a given vibrational state for a given relaxer. The colliders  C@* that had the fastest relaxation rate constants were SO2, CH4 and@*D,,,  C CH3Cl, suggesting the more efficient gases for collisional relaxati C onal process in SO radicals are SO2, CH4 and CH3Cl.  ?(  58 Name of Presenter: David Simchen Institution: Arizona State University Classification: Junior Major Area of Study: Chemistry NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. A. J. Ashe, III  ?0 Aromacity of the Phospholyl Anion The phospholyl ANION C4H4P is the phosphorous analog of the Aromatic C5H5-. We hope to measure its gas phase proton affinity since this quantity should be a measure of the aromaticity of C4H4P-. The anion will be generated by the gas phase reaction of F- with i-t-butylphosphole. We have prepared i-t-butyl phosphate by the following route: 59 Name of Presenter: Ivn O. Rivera Torres Institution: University of Puerto Rico Classification: Sophomore Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Jos) Ram;n Ortiz LectinBinding Glycoproteins on Transdifferentiation During Lens Regeneration in Notophthalmus Viridescens Following lentectomy in Notophthalmus viridescens, a regulated celltype conversion process is initiated and the cells from the dorsal iris ephitelium (IEC's) transdifferentiate into lens fibers. Being fully differentiated melanocytes, IEC's experience several morphological and biochemical events such as membrane alterations and depigmentation. A characterization of lectinbinding glycoproteins on IEC's undergoing dedifferentiation was conducted. Immunocytochemistry was carried in our normal eyes using Fluores C! cein isothiocyanate (FITC) conjugated Peanut lectin (PNAFITC, 10é7M in 80% PBS). Goat Serum was used to avoid nonspecific binding. Results showed intense fluorescence in the dorsal and ventral iris pigmented epithelium and stroma, Brunch's membrane of the neural retina, and Bowman's membrane in the cornea. A weak signal was observed in Inner Limiting membrane and lens capsule. No signal was observed in Descement's membrane and the stroma of the cornea. Five days regenerates showed a general decrease in signal, mostly during redifferentiation. The signal reappeared in ten and fifteen days regenerates in the dorsal and ventral epithelium. Results indicated changes in cell surface glycoproteins of IEC's involved in lens regeneration in vivo. Presence of DGalactose expressed suprabasally is suggested, since it binds PNA.+E,,,Ԍ  ?  60 Name of Presenter: Ila Waldon Institution: Mississippi State University Classification: Senior Major Area of Study: Mechanical Engineering NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Evelyn Goldfield Time-Dependent Quantum Mechanical Study of the Photodissociation of  ? HCO Via a Renner-Teller Mechanism Wavepackets will be used to study the predissociation of HCO which has been excited from the ground state to an excited state (the A state). This predissociation occurs due to Renner-Telling coupling between the two states near the collinear configuration. In this project, the student will use existing wavepacket code to study the predissociation, develop tools (including visualization tools) to analyze numerical results, and make an animated video of the dissociating wavepackets.  ?  61 Name of Presenter: Marilyn D. Wyatt Institution: Tougaloo College Classification: Sophomore Major Area of Study: Biology NSF Sponsoring Program: AMP Faculty Advisor or Mentor: Dr. Asim Bej Adaptive Acid Tolerance Response (ATR) in Helicobacter Pylori and  ? Vibrio Cholerae H. pylori is considered as the causative agent for peptic ulcer and chronic gastritis, and possibly gastric cancers in humans. Another pathogen, V. cholerae, is an etiologic agent for cholera causing millions of deaths every year especially in developing countries. To determine their survival in the stomach acid environment, an adaptive ATR has been studied. Both bacterial pathogens showed adaptation to low pH conditions in liquid media. Microscopic examinations showed changes in the cellular morphology during low pH conditions, which are caused by changes in the cellular physiology and possibly genetic regulation. A bacterial ATPase gene which is known to participate in ATR showed positive hybridization signals in both H. pylori and V. cholerae, which suggests the presence of this gene in these pathogens. Also, a positive hybridization signal using a protooncogene with the genomic DNA of H. pylori indicated the presence of this gene which may cause gastric cancer in humans. 'F,,, RESEARCH CAREERS FOR MINORITY SCHOLARS (RCMS)  ?  62 Name of Presenter: Felipe J. Acosta Institution: University of Puerto RicoMayagGez Classification: Senior Major Area of Study: Civil Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Carlos Pesquera  ?  Effects of CrossSection Variation in the Response of Continuous  ?` Beams Subjected Highway Traffic Loads The response of continuous beams typical of highway bridge construction to applied loads is influenced by the beam crosssection variation along it's length. This influence is typically neglected in routine design. To design this type of structural element, it is necessary to stimulate moving trucks along the beam, perform a structural analysis of the model, and register the critical responses at discrete points along the beam length. This study is a comparison of critical responses for different beam geometric forms, to determine the effects of neglecting the crosssection variation in design. Numerical integration using Gauss Quadrature was used to compute the stiffness coefficients of each beam segment. Any combination of linear and parabolic crosssection variation can be used to define geometric forms. An interactive computer graphics program has been developed to integrate the definition of models, the loading simulations and the response evaluation processes. 63 Name of Presenter: Elias Amaro Institution: City College of New York Classification: Junior Major Area of Study: Electrical Engineering NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Derek Lindsay  B  A New Method of C60 Synthesis  Cc" A new method of synthesizing C60 using a variant of the "Bredig's arc" technique for forming colloidal metal suspensions is being investigated. In the experiments outlined here, a discharge was maintained between two electrodes immersed in an organic solvent. The solvent, but not the material composition (C or Ti) of the electrodes, was found to be most significant in determining the  C' products formed. With CCl4 as the solvent, U.V. absorption spectra showed a strong peak at 217 nm together with relatively weaker features at 230, 247, and 257 nm, thus indicating the possible  Cs) presence of C60 in combination with other materials. A mass spectrum of this sample gave a moderately strong peak at 720 amu,  C+ indicative of the formation of C60.+G,,,Ԍ  ?  64 Name of Presenter: Stanley Angus Institution: University of Maryland Baltimore County Classification: Junior Major Area of Study: Biological Sciences NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Cuthbert O. Simpkins  ?  Reduction of Cytochrome C by Heat Shock Protein 70 (HSP) Previously we showed that reduction of cytochrome c (CC) by di and tripeptides was optimized by increasing hydrophobicity, negative charge, and the presence of cysteine in the peptide. Since HSP has these characteristics we sought to determine whether HSP would reduce CC. Presently, we report that CC is reduced by  CH HSP of E. coli. HST caused changes in the absorbance spectrum that are characteristic of reduction, with peaks at 550 and 520nM and a shift to the right of the Soret peak. At CC = 20uM, pH = 7.4, Tris  C 50mM and 50% glycerol/water we obtained a Km of 0.7uM and Vmax = 7.4uM/min. Reduction was detected at concentrations as low as 40nM. HSP at 0.5uM was completely inhibited by 1mM EDTA. This was consistent with similar inhibition by EDTA of reduction of CC by glutathione, a tripeptide with cysteine as the active moiety. Also Nterminal, highly conserved fragments of HSP, SerCysVal and TyrSerCysValGLyValPhe were shown to be inhibited by EDTA. This finding suggests the possibility of an interaction between heat shock proteins and cytochrome proteins, that could alter cellular function.  ?  65 Name of Presenter: Maria Cristina Asensio Institution: Texas A&M University Classification: Senior Major Area of Study: Mechanical Engineering NSF Sponsored Program: RCMS Faculty Advisor: Dr. Jamal SeyedYagoobi  ?  Simulation of Paper Drying Systems with Incorporation of an  ? Experimental Drum/Paper Thermal Contact Conductance Relationship A theoretical model for simulation of conventional steamheated cylinder dryers is developed by considering the heat and mass transfer in a porous sheet during drying. Am empirical correlation for the thermal contact conductance between the cast iron dryer surface and paper web is incorporated into the drying simulation model to reflect reductions in heat input to the sheet during drying. Expressions for sheet shrinkage as a function of mass water removed and for reductions in sheet porosity are also developed for inclusion in the model. Average sheet moisture content and temperature along the length of the dryer section as well as average evaporation rates per cylinder+H,,, are predicted by the model. Profiles of sheet moisture content, temperature, liquid flux, and vapor flux through the sheet thickness are predicted throughout the dryer section. Drying results are consistent with actual production cases. The model can be used to design dryer sections, study changes in operating conditions or layout of a multicylinder dryer, or simulate the application of enhanced energy devices to a conventional drying section.  ?  66 Name of Presenter: R. Christian Bartley Institution: Marquette University Classification: Sophomore Major Area of Study: Mechanical Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Vikram Cariapa  ?  Stereolithography A Tool for Engineering Education  ?h  The objective of this research is to establish the process of stereolithography as a viable teaching/learning and design tool for engineering. The initial phase involves the generation of a CAD design manual for a computer software package so that product concepts can easily be developed on a computer screen. The second phase involves testing of stereolithography resins to establish wear, hardness and tensile properties. Finally a series of complex assemblies will be constructed so that the potential of stereolithography may be further developed.  ?  67  ?  Name of Presenter: Matthew E. Beatie Institution: San Diego State University Classification: Senior Major Area of Study: Chemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Morey A. Ring  ?  The Thermal Decomposition of n-Propylsilane The kinetics of the thermal decomposition of n-propylsilane is being carried out. The decomposition had been previously studied in this laboratory at very high temperature in a single pulse shock-tube. The operating parameters for the shock-tube system were 4700 torr and between 1095-1240 K. The major products from the previous study were propylene and ethylene. The kinetic results from the study led to a mechanism and Arrhenius parameters for each step in the mechanism. The current study will be carried out to further verify the conclusions based on the limited parameters used in the shock-tube study. Presently, the temperature range is 703-723 K and a much lower pressure range. This new data will allow for an Arrhenius plot over a larger magnitude of temperature data points, which will improve the accuracy of the conclusions of the past study. The products+I,,, obtained in the present study are silane, ethylene, propylene and propenylsilane in minor amounts, which were expected from the shock-tube results. For the previous study, the calculated value of the rate constant for the initial step of the mechanism, that is propylsilane decomposing to propylsilylene and molecular hydrogen,  C is approximately 9.07 X 10-6 extrapolated to 703 K while the rate  C constant for propylsilane is 3.52 X 10-5 for the present study. The greater value of the rate constant in the present study is presumably due to chain reactions proposed in the mechanism.  ?  68 Name of Presenter: Chris Bedoy Institution: Harvey Mudd College Classification: Sophomore Major Area of Study: Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Richard Haskell  ?  "Rooftop Project": Evaluation of Photovoltaic Modules at Standard  ? Residential Roofing Pitches A study is in progress to determine the efficiency and performance of photovoltaic modules at standard residential roofing pitches. Using fifteen semi-crystalline Solarex MSX-60 and twelve Arco M55 photovoltaic modules we modeled the most common roof pitches or tilt angles of 18.5, 26.5, and 45 degrees. The results of our study will give us a better understanding of how surrounding conditions such as module orientation, thermal loading, and insolation affect the overall system behavior. Using the Solarex and Arco modules, we set up eight arrays at different orientations and tilt angles. Furthermore, all the arrays were wired into a Campbell Scientific (CR-10) data acquisition unit. All incoming data was then sampled once every two seconds, averaged at hourly intervals, and then transferred to a Macintosh computer for further analysis. Based upon the data obtained we will discuss the performance of the Solarex and Arco modules at specific orientations and tilt angles, and we will describe the system losses for the actual residential roofing pitches. Our results enable us to select a cost-effective photovoltaic system for particular design specifications.  ?0#  69 Name of Presenter: Francene R. Benally Institution: Northern Arizona University Classification: Junior Major Area of Study: Forest Genetics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Michael Wagner  ?8*  The Effects of Geographic Origin on Ponderosa Pine Survivability  ?+ Near Flagstagg, Arizona +J,,,ԌBecause Ponderosa Pine (Pinus ponderosa) grows in many areas of the United States, the possibility exists that certain regions have provided superior strains. Seeds from different geographic origins were grown in a greenhouse, hardened, and then planted in 1988. Total survivability and growth were measured in 1991 and 1992. Using analysis of variance, tests were performed to see if there were significant differences in growth rates of pine of local origin in comparison to pine from other areas of the country.  ?  70 Name of Presenter: Jormell F. Bland Institution: Grambling State University Classification: Senior Major Area of Study: Chemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Frank Ohene  ?  The Study of the Effect of Coal Properties on the Rheology of Coal ? **/Water Slurries The relationship between characteristic coal properties (moisture, carbon, oxygen, volatile matter, fixed carbon, natural pH, Hardgove Grindability Index, and Ash Content) and the coal content in a coal water slurry, (CWS), was studied by using a multivariate analysis technique, to determine the parameters that affect the coal slurry content. An empirical predictive model that relates the coal  C content to the coal properties at a shear rate of 100 sé1 has been developed and this has been verified through experiments. The experiments performed include studying the effects of surface properties and the influence of chemical additives on the rheology and stability of the CWS. The empirical model was found to predict the coal slurry content from the coal properties with reasonable accuracy.  ?  71 Name of Presenter: Yara I. Alma Bonilla Institution: Massachusetts Institute of Technology Classification: Freshman Major Area of Study: Astrophysics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Paul Schechter  ?#  Local Group Distance Matrix Recent approaches to determining the distances to nearby galaxies have used either several distance indicators applied to one galaxy or one distance indicator applied to several different galaxies. Since measurements to the same galaxy do not always agree, we are using several approaches simultaneously to get estimates. We start by grouping measurements obtained through RR Lyraes into one set (including a distance to the Large Magellanic Cloud and a distance the center of the Milky Way), and those obtained through kinematic*K,,, parallaxes into another. We then produce error ellipses, taking into account correlations, given common methods of calculation. With these we'll then obtain a weighted ellipse, which will provide a best estimate for each distance with a smaller uncertainty. Our goal is to expand each set of values by including measurements to other galaxies and adding new distance indicators, that will further improve the estimates.  ?  72  ?  Name of Presenter: Alejandro Borgia Institution: Princeton University Classification: Sophomore Major Area of Study: Computer Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Eric Ristad  ?  Handwriting Recognition The recognition of human handwriting by machines is a problem which currently has, at best, mediocre solutions. The goal of my research is to create a recognition system that learns about the biomechanical properties of human handwriting to improve recognition performance. In order to do this, we need to collect a database of writing samples annotated with a symbolic script. A user interface must be designed so that such data can be collected. We must compute features such as grasp and distribution of kinematic and dynamic variables, and model abstract manipulator degrees of freedom. Unsupervised classification of writing based on the features will determine which features are useful in predicting writing style. We will use the database to train a Hidden Markov Model for handwriting recognition. 73  ?x  Name of Presenter: Vivian Rosa Casanas Institution: Scripps Institution of Oceanography Classification: Graduate Student Major Area of Study: Marine Biology NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Jerry Kooyman Plasma Growth Hormone Concentrations in Northern Fur Seal (Callorhinus Ursinus) Pups and Adults Basal plasma Growth Hormone (GH) concentrations and secretory patterns for Northern Fur Seals (Callorhinus ursinus) were analyzed, and compared to GH concentrations measured during varying physiological states including feeding, fasting and starvation. A radioimmunoassay with the specific sensitivity to make these measurements was developed and is described. *L,,,ԌBasal GH concentrations were 4.6 +/ .67 ng/ml for adults and 6.2 +/ 1.7 ng/ml for pups. Mean GH concentrations in feeding pup were found to be 7.21 +/ 2.5 ng/ml. This is slightly lower than the concentrations found in fasting pups which were 7.94 +/ 2.9 ng/ml. Starving pup GH concentrations were significantly higher than all other groups, with levels measuring 22.55 +/ 7.4 ng/ml. GH secretory patterns were monitored over a 24 hour period and showed a significant peak between 1730 and 2100 hours. The mean value of this peak was 7.4 +/ .89 ng/ml. During the remainder of the 24 hours, GH concentrations were approximately 6 ng/ml. These are the first reported GH measurements in pinnipeds.  ?(  74  ?  Name of Presenter: Paul Cerda Institution: Texas A&M University Classification: Senior Major Area of Study: Mechanical Engineering NSF Sponsored Program: RCMS Faculty Advisor: Dr. Sherif Noah  ?0  Dynamical Systems Response to Chaotic Excitation Summer The research to be presented in this abstract is in conjunction with work that is currently being pursued by Dr. Sherif Noah of Texas A&M and his graduate students. The research aims to demonstrate the potential of using modern dynamical system theory, in particular deterministic chaos, to develop reliable procedures for crack detection in structural and rotor systems. The research considers using a chaotic signal as an input into mechanical systems, i.e., linear and nonlinear systems. A chaotic signal carries a wealth of information, and unlike analytical methods using periodic or random signal, is very sensitive to the parameters of the system. Detection of changes in the parameters of the system appears to be assessable through constructing Poincare' maps, probability density functions and frequency spectra of response amplitudes, but more significantly by the position of the unstable periodic orbits of the chaotic attractor associated with the chaotic response of the system.  ?!  75  ?(#  Name of Presenter: Carlos Chacon Institution: Marquette University Classification: Sophomore Major Area of Study: Mechanical Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. William Brower  ?(  Rapid Prototyping at Zero Gravity for InFlight Repair and Fabrication in Space Station Freedom The project involves the use of a 3D Systems Model 250 Stereolithography machine (SLA), which uses a laser to polymerize+M,,, a special liquid resin. The SLA solidifies the resin layer by layer to create an actual model of any threedimensional computer aided design model. The ultimate goal of the project is to make it possible to use the SLA in the microgravity of an orbiting space station. Specifically, the purpose of the project is to create a container with a lid that will keep the liquid resin from changing position and will allow the laser light to penetrate through. To this point, a possible container and lid have been created using the SLA, and several drop experiments have been conducted in an attempt to simulate a near zero gravity environment to determine if the lid can contain the resin. Work up to this point has attempted to determine the best way to drop the container and to photograph the top of the lid during freefall.  ?  76 Name of Presenter: Tobi Clinton Institution: Harvey Mudd College Classification: Freshman Major Area of Study: Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Richard Haskell  ?  Calibration of an Ultrasonic System for Improved Hyperthermia Treatment Clinical data suggests that hyperthermia improves the effectiveness of radiation therapy when adequate hyperthermia is delivered. Technical difficulty arises when delivering hyperthermia to deep or very small tumors. One hyperthermia technique is localized treatment using external, unfocused ultrasound transducers. The SONOTHERM 1000 (Labthermics Technologies Inc.) was designed to overcome many of the significant limitations of other hyperthermia systems. The apparatus is capable of treating tumors to depths of 8 cm. Its multisector applicator heats to the very edge of the aperture, allowing large tumors (lateral measurements up to 15 cm by 15 cm) to be heated. Each of its sixteen sectors can be varied between 0 - 100% power to uniformly heat across the volume of the tumor being treated. The depth of energy penentration can be adjusted by changing the frequency (1 MHz and 3.4 MHz). Using a hydrophone mounted on an x-y scanner, we recorded the ultrasound intensity produced by the SONOTHERM 1000 applicator. With the data collected, we created a calibration map which can be used in clinical applications.  ?'  77  ?h)  Name of Presenter: Ricko Cordova Institution: Marquette University Classification: Sophomore Major Area of Study: Mechanical Engineering+N,,,ԌNSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Richard Schoenmarklin  ?X  Calibration of the Whole Body Strength Tester A whole body strength tester is a device used in the ergonomics field to evaluate whether a potential worker has sufficient strength to perform a manual materials handling (MMH) job in industry. A whole body isometric strength tester was designed and built by students and staff for Marquette University's Industrial Ergonomics Laboratory, which is directed by Dr. Richard Schoenmarklin. This strength tester measures isometric forces exerted in pushing, pulling, and lifting postures. Ricko Cordova's responsibility was to calibrate this strength tester so it can be used in research experiments at Marquette University and in local industries. The sensor in the strength tester is 1,000 lb. compression and tension load cell. Using an analog to digital converter and a PC, Mr. Cordova conducted an experiment in which he measured the output voltages and the sensor loaded with a series of weights attached to the tester in the lifting and pulling orientations. The data were transferred to a spreadsheet program and plotted. The data were checked visually for linearity, and statistical correlations were computed. The gain on the load cell was adjusted so the slope of calibration line was 200 lbs./volt. In addition, the output voltages were adjusted to minimize offset. This experiment was conducted three times to ensure that calibration was stable over time.  ?8  78  ?  Name of Presenter: Byron Davis Institution: University of Oklahoma Classification: Senior Major Area of Study: Electrical Engineering NSF Sponsored Program: RCMS Faculty Advisor: Dr. J. Sluss  ?@ Electronic Speckle Pattern Interferometry for Materials Analysis Electronic Speckle Pattern Interferometry (ESPI) is a technique used to measure small changes in the shape and position of an object. This technique uses interference fringes, a light and dark pattern, to determine the amount of change of a specific object. Using the principle of superposition, a reference and object beam are added algebraically to produce the interference fringes. At the point of detection both beams must be of equal intensity in order to have complete periodic destruction of the wavefronts to provide a more distinct fringe pattern. The light arriving at the detection point from the object beam is reflected off the specified object. The intensity of this reflected light is much less than that of the unobstructed reference beam. Therefore, the reference beam must be attenuated in order to achieve the best results. +O,,,ԌThe thrust of this experiment was to interpret and quantify the data generated from interference fringes produced by the deformation of a half inch diameter steel rod.  ?  79  ?x  Name of Presenter: Michael A. Davis Institution: Jackson State University Classification: Junior Major Area of Study: Biology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Charles Rhyne  B  The Effects of 16, 16dimethylprostaglandin E2 on Human Intestinal Colon Cells  CK 16, 16dimethylprostaglandin E2 (dmPGE) is known to protect the stomach epithelium from noxious irritants such as alcohol or aspirin, and to accelerate ulcer healing. In this study, we used  C the N2 goblet cell line to investigate the effect of dmPGE on the secretion of mucus, the growth response, and its protection against irritants. To assay secretion, a monolayer of cells was exposed to various concentrations of dmPGE. The highest secretory stimulation was achieved at 100M/ml, while there was no increased mucus secretion at 1M/ml or 10M/ml. To determine if dmPGE had any effect on the growth, cells were grown in 0, 0.1,1, and 10M for 10 days. After counting during alternating days, it was determined that dmPGE did not increase the cell proliferation rate. To evaluate cell injury and the presence of protection, a model irritant (ethanol) was used. It was determined that dmPGE did not  CC protect proliferating (nonmucus producing) N2 cells.  ?g  80  ?  Name of Presenter: Julie Dike Institution: City College of New York Classification: Senior Major Area of Study: Electrical Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Prof. Joseph Johnson  ?o"  Application of Mathematica to Solutions of Flow Simulations and  B7# Solutions of ElectronMolecule Scattering of H2+ Mathematica, a general software system for mathematical applications, has great potential usefulness for problems in fluid dynamics and atomic and molecular processes. Numerical models for modemode coupling have been created in Mathematica and multidimensional Fourier transforms have been studied. Results from a  C( technique for electron scattering of H2+ provide functions which are sensitive to changes in radial and polar variables on a numerical grid. The observed results provide an insight on the appropriateness of modemode coupling as a model for turbulent+P,,, flows and for the propagation and resolution of the scattering function solutions. Mathematica is expected to be very useful in more elaborate electron scattering of polyatomic molecules and for more complicated flow simulations. 81  ?@  Name of Presenter: LaShondria B. Dixon Institution: Oklahoma State University Classification: Junior Major Area of Study: Physics  ?` NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. H. L. Scott  ?  A Metropolis Monte Carlo Method for Simulating ThreeDimentional OffLattice Ballistic Deposition with Limited Surface Diffusion The deposition of materials on to surfaces is of considerable interest to many scientific developers. The main objective was to simulate models for ballistic deposition with and without restructuring mechanisms that allowed for little or no surface diffusion under the influence of an external gravitational field, which could be applicable to any general deposition system. The simple restructuring mechanism, which allowed for limited surface diffusion, was used to display the varying degrees of deposition in contrast to those without restructuring. Changing parameters, such as the temperature of the system, produced quite noticeable and interesting effects. Applications of thinfilm deposition models such as this have a broad range of practical applications including a variety of optical, solid state, magnetic, and electronic devices.  ?  82  ?   Name of Presenter: Ursula Donatto Institution: Grambling State University Classification: Senior Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. A. N. Murty  ?!  Magnetic Character Investigation of Higher Alcohol Synthesis CuCoCr Catalysts The selectivity and conversion efficiency are reported to be governed by intermetallic ratios of elements in the catalyst. High yields of methanol in copper rich field, hydrocarbons in cobalt rich field and mixed alcohols in the intermediate range were observed. Neither the basic mechanism and the extent and effect of intermetallic interactions nor the role and function of chromium are clearly understood. We have investigated the Zerofield Nuclear Magnetic Resonance spectra and Hysteresis character of a series of Cu/Co/Cr trimetallics with Cu/Co ratio ranging from 0.2 to 8.0. The+Q,,, magnetic behavior of the catalyst reveals interesting correlations between catalytic and magnetic properties. The magnetic moment of the catalyst system is very low for Cu/Co < 1.5, dramatically increases when 1.5 < Cu/Co < 5.0 and drops for Cu/Co > 5.0. The NMR results indicate that chromium serves as a support and inhibits any strong intermetallic interaction between copper and cobalt.  ?@  83  ?  Name of Presenter: Tracy T. Edwards Institution: City College of New York Classification: Junior Major Area of Study: Biology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Louis Levine  ?H  Desiccation Resistance in Natural Populations of Two Sibling Species in the Genus Drosophila from Laguna Verde, Veracruz, MEXICO I study desiccation resistance of Drosophila (fruit flies). The sibling species Drosophila melanogaster and D. simulans were collected form a site near Mexico's first nuclear power plant. Sibling species are both morphologically and phylogenetically similar, but genetically and chromosomally distinct. Flies were tested for desiccation resistance at 0% relative  C humidity, 20C and constant light. Readings of the number of flies alive were taken at 4h, 8h, 12h and 24h. the collections took place in January (a cool and dry season) and July (a warm and more humid season). Results showed that D. melanogaster is more resistant to desiccation than D. simulans. Also, in both species, females are more resistant to desiccation than males. There was no indication of seasonal variation among the males or females of either species. The sibling species will be used as "monitors" of the biological effects of the operation of the nuclear power plant.  ?D  84  ?  Name of Presenter: Ako Emanuel Institution: Jackson State University Classification: Junior Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Keith W. Johnson  ?L&  Wave in Galaxy Disks Following Slightly Off-Center Collisions A typical galaxy probably experiences several collisions and reorientations over the age of the universe. Such collisions cause wave-like formations within the galactic disk. These interactions have a profound effect on the galaxy structure and later evolution. For example, waves generated in a galactic disk may trigger nearly*R,,, circular, ring-like patterns of star formation, and increase random motions of old stars. Simulations of waveforms in interstellar gas in a galaxy disk following a nearly head-on, direct collision show that the further the impact is from the center, the more asymmetric the patterns of waves. In these simulations regions of greatest gas compression are noted and compared to observations of sites of star formation in colliding galaxies. Hopefully, correlations found between wave formations in simulated galaxies and young star concentration in actual galaxies will provide some insight into galactic evolution and the process of large-scale star formation.  ?`  85  ?  Name of Presenter: Joy E. Ferris Institution: Oklahoma State University Classification: Graduate Student Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. David W. Hart A Study of the Etch-Channel Concentration in Quartz as a Function of Electrodiffusion Time Electrodiffusion (sweeping) affects point defects such as the substitutional aluminum with its associated interstitial alkali and the extended dislocation networks with their precipitated impurities that form the etch channels. Quartz is commercially swept to reduce the formation of etch-channels which are produced during photo lithographic resonator processing and to improve radiation hardness for aerospace applications. AT-cut wafers taken from a single bar of Premium-Q grade quartz were swept for times  C ranging from 15 minutes to 200 hours at 490oC. Both the Al-OH infrared absorption band and the sweeping current were used to indicate the effectiveness of the process on the point defects.  C\ The wafers were then etched in a saturated NH4HF2 solution at 75oC. The etch-channel concentration was found to decrease more slowly than expected from the formation of the Al-OH center. Supported by NSF Grant No. RII9014688.  ?  86  ?!  Name of Presenter: Harold K. Figueroa Institution: University of Puerto RicoMayagGez Classification: Senior Major Area of Study: Mathematics/ Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Jaime Seguel  ?'  Communication Complexity of Parallel Liner Algebra Algorithms in Multiprocessor Computing Architectures In this project, we deal with the problem of finding highly parallel algorithms to compute matrixvector products, for a specified matrix A of size N x N and arbitrary vector of+S,,, appropriate size, such that these archive minimal communication complexity when implemented on a specified multiprocessor architecture with N processing elements. We find these algorithms through a constructive process which is based on an appropriate description of the multiprocessor architecture using graph and group theory, and a special decomposition of the matrix A based on the developed representation of the architecture and elements of group representation theory. The construction process can be expressed as an algorithm, leading to the possibility of automation of the algorithm selection and implementation process. The theoretical framework and construction process for minimal communication complexity algorithm will be presented.  ?  87  ?H  Name of Presenter: Iddys D. Figueroa Institution: University of Puerto RicoR1o Piedras Classification: Senior Major Area of Study: Chemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Osvaldo Rosario  ?  Supercritical Fluid Extraction in the Analysis of Environmental Organic Pollutants Several conventional methods of extraction are used in environmental analysis chemistry. The extraction should remove as effectively as possible the compounds of interest from the matrix being studied. The majority of methods being used require the use of organic solvents that presents problems of sample dilution, disposal and toxicity. Recently, interest has emerged in a relatively new technique of extraction called Supercritical Fluid Extraction (SFE). Recovery percentages observed using SFE are very high and also this technique eliminates the use of organic solvents because the fluid  C most commonly used is CO2. Very little has been reported in environmental studies. This work undertook the design, construction and testing of a system for SFE. Standards of organic compounds representative of pollutants of concern were loaded onto different absorbents used in sampling. Optimum extraction conditions were determined for sample recovery. The results show SFE as a highly efficient approach for environmental analysis.  ?L&  88  ?'  Name of Presenter: Michael N. Fisher Institution: Jackson State University/Lawrence Livermore National XX` `  Laboratory(#` Classification: Sophomore Major Area of Study: Math/Physics/Preengineering*T,,,ԌNSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Ronnie Shepherd and Dr. Lonzy Lewis  ?X  The Design and Construction of an Xray Pinhole Camera for Ultra Short Pulsed Laser Produced Plasmas A 100 femtosecond, 8000 angstrom ultra short pulsed laser is used to create 100 electron Volts 300 electron Volts plasmas from aluminum targets. Xrays emitted by the plasma are imaged by a light tight xray pinhole camera that has a 2.5 micrometer pinhole and a magnification of 20. The camera is made of a 100 cm long steel tube with an inside diameter of 0.95 cm, and outside diameter of 1.275 cm and utilizes a 0.375 inch threaded screw for a film holder. The detector medium is currently direct exposure xray film but plans have been made to interface the pinhole camera to a micro channel plate detector which will increase the sensitivity by a factor 10,000.  ?  89  ?h  Name of Presenter: Dionne M. Franklin Institution: Southern University Classification: Senior Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Diola Bagayoko and Dr. David Knapp  ?  Bound State Beta Decay A series of experiments has been proposed to observe bound state beta decay using the Super Electron Beam Ion Trap (SuperEBIT) at Lawrence Livermore National Laboratory (LLNL). The process occurs when the nucleus decays by creating a bound electron in a vacant atomic orbital. During the experiment, parent ions are injected into the trap where they are stripped of their atomic electrons. The buildup of daughter ions is monitored by radiative recombination over a period of several hours. The first  C observation is that of the bound state beta decay of 163Dy to 165Ho. Trap experiments to measure conditions needed to achieve bound state beta decay will be discussed. These conditions include the current density, the beam energy, and the ionization balance.  ?d"  90  ?#  Name of Presenter: Brian Gaffney Institution: Morehouse College Classification: Freshman Major Area of Study: Biology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Clarence Clark  ?l)  Characterization of RPlasmid DNA in Pseudomonas Multifilia 4*U,,,ԌUnderstanding the functions of the membrane as it relates to bacterial plasmid DNA maintenance (replication and/or segregation into daughter cellspartitioning) has been the focus of our investigations. Members of the Genus, Pseudomonas, are important clinical opportunistic pathogens. In our laboratory, a clinical isolate of Pseudomonas multifilia has demonstrated resistance to (8) antibiotics. To establish whether extrachromosomal elements, i.e., plasmid DNA, were present and harboring antibiotic loci, cultures were subjected to cesiumchloride ethidiumbromide (CsClEtBr) buoyant density gradient centrifugation. Covalently closed circular (CCC) plasmid DNA was isolated and transformed into a DH5 competent strain of Escherichia coli. The transformants were resistant to streptomycin and novobiocin. Purified CCC DNA from the E. coli transformants and P. multifilia were analyzed on agarose gel electrophoresis and found to have identical banding patterns. Partial restriction enzyme mapping of plasmid DNA along with in vitro investigations of plasmid DNAmembrane interactions will be reported.  ?  91  ?0  Name of Presenter: Darelene Graham Institution: Hampton University Classification: Senior Major Area of Study: Biology NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Barbara Shipes  ?  Inhibiting Fungicides Growth curve studies and gas chromatograph analysis have shown that fungi specific sterol inhibiting fungicides greatly inhibit the reproduction of Pheeodactylum tricornutum and Oocystis minute. These fungicides, even at concentrations as small as five to ten parts per million, inhibit sterol synthesis in these algae species by blocking biosynthetic pathways causing a build up of sterol precursors. By inhibiting sterol production their functions, especially in growth and cell division, are also inhibited.  ?  92  ?!  Name of Presenter: Malaika T. Griffin Institution: Jackson State University Classification: Junior Major Area of Study: Chemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Hiroyasu Tachikawa  ?'  Imaging Surfaces with the Scanning Tunneling Microscope Graphite surface structures were investigated using the Scanning Tunneling Microscope. Experimental results indicated that the best resolution of graphite occurred under conditions in which the Scanning Tunneling Microscope was under low noise level and had a sharp scanning probe. Also, when the graphite's surface was as+V,,, flat as possible, the surface topography had a better resolution. Studies of DNA and gold on graphite were also carried out. An essential understanding of the Scanning Tunneling Microscope was obtained.  ?x  93  ?  Name of Presenter: Jacquelin Guiteau Institution: City College of New York Classification: Senior Major Area of Study: Electrical Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Professor William Edmonson  ?  Interactive Visualization for Teaching of Signal and Systems Concepts In the teaching of beginning level electrical engineering courses, it is sometimes difficult for the student to grasp the basic concepts. These concepts though abstract in nature are the basis for understanding the senior level electrical engineering coursework. By visualizing these abstract concepts the students will be able to ascertain their meaning. The visualization will also be interactive in that the student will be able to adjust pertinent parameters to invoke the appropriate visual response. A study of hypermedia on PC's to act as a font end to the numerical processing will be discussed. MATLAB will handle the numerical processing. An interface mechanism between the two will be outlined. The paradigm for testing the interactive visualization will be in the area of digital signal and systems.  ?  94  ?   Name of Presenter: Chenita D. Hampton Institution: Southern University Classification: Senior Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Diola Bagayoko  ?!  AC Susceptibility of Fullerides  C(# We present studies of the ac susceptibility of C60 doped with Rb2K. This work was partly aimed at replicating the high volume fraction reported to be associated with ac susceptibility, developing a method for estimating the transition temperature, and studied frequency effects, if any, on the transition temperature. In this study, all doping reactions and measurements were carried out using  C' sealed tubes. C60 was purified by chromatography of fulleride on octadecylsilanised silica with toluene/isopropanol eluent, and dried at 100 C under vacuum. We used coils consisting of 600 turns on the primary and 1400 turns on the secondary. We utilized frequencies of 17 Hz, 100 Hz, and 1kHz. Our results showed, as+W,,, compared to the dc susceptibility measurements, that there was no frequency dependence and Tc was the same (26$K). We also showed that the ac susceptibility method gives an overestimate of volume fraction, 100% as compared to 15% with dc susceptibility.  ?  95  ?x  Name of Presenter: Antonio Hart Institution: Talladega College Classification: Senior Major Area of Study: Computer Science NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. William Campbell  ?  Binary Decision Program Diagrams (BDD'S) Binary decision program diagrams (BDD's) are data structures for representing and manipulating boolean functions. They have been shown to be a very efficient and flexible representation for modeling and analysis of combinational circuits. Recently, BDD's have also been proposed as an efficient symbolic representation of a transition relation in a finite-state model of parallel computation. Manipulation of BDD representations of transition relations has exhibited spectacular performance on a few example problems in verifying the behavior of sequential circuits, but the conditions under which good performance can be expected (and encoding methods required to achieve good performance) are not yet well understood. This research proposes, implementation of a software package for manipulation of binary decision diagrams, followed by experimental and analytical investigation of the conditions under which binary decision diagrams are a suitable representation of a set of transition relations. 96  ?   Name of Presenter: Mikita L. Heath Institution: Talladega College Classification: Senior Major Area of Study: Mathematics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. William Campbell  ?!  Development of Computer Systems for the Development of Traffic Crash Countermeasures This research involved the design, development and application of large databases to traffic safety applications. This project was in conjunction with a contract sponsored by the National Highway Traffic Safety Administration, for the development of database systems used to perform problem identifications for traffic safety purposes. A very large number of database queries were performed and used to compare the characteristics of subsets of the accident records database. The particular example presented involved a comparison of the subset of casual drivers who wore restraints against those who did not. Data showed that countermeasures should*X,,, be directed toward young males from rural areas who are in the lower economic classification. Drivers of pickup trucks were also found to be less apt to be restrained than those of other types of vehicles.  ?x  97  ?  Name of Presenter: Amalia C. Himaya Institution: University of Guam Classification: Graduate Student Major Area of Study: Biology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. R. Glenn Northcutt  ?  The Ampullary Organs of the Postotic Line The postotic ampullary organs or electroreceptors of salamander Ambystoma mexicanum were examined. This is to determine if the initial development of postotoc electroceptors are possibly induced by an anteroventral lateral line nerve. This nerve arises from a nonpostotic placode. This is of interest since most placodes give rise to both lateral line organs and the nerves that innervate these organs. To test the hypothesis that postotic electroreceptors are induced by the anteroventral lateral line nerve, it is necessary to verify that electroreceptors (1) arise from postotic placodes; and (2) will not form in the absence of an anteroventral lateral line nerve or placode. The procedure involved the extirpation of embryonic tissue from the postotic placode of a wild type embryo which is to be transplanted to the postotic placodal area of an albino embryo. Electroreceptors are expected to be absent in the wildtype embryo and present as pigmented electroreceptors in the albino embryo. The result is inconclusive and further tests are needed.  ?  98  ?x  Name of Presenter: Vermettya Hodge Institution: Harvey Mudd College Classification: Freshman Major Area of Study: Biology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Richard Haskell  ?#  Understanding Interferons: Attempts to Clone the Enzyme RNase L Our research goal is to determine the mechanisms by which interferons (IFNs) exert anti-proliferative effects on cells. The anti-viral response seen in IFN-treated cells is associated with the activation of the (2'-5')An Synthetase-RNase L Pathway which decreases levels of viral RNA. It is hypothesized that this (2'-5')An Synthetase-RNase L Pathway may regulate "oncogene" or "proto-oncogene" expression, which is a growth regulatory gene associated with tumorigenesis. The immediate project is to purify the endonuclease RNase L by isolating the gene that encodes for its+Y,,, amino acid sequence. Isolation of the gene will enable researchers to mass produce the enzyme to study its basic biochemistry and structure. It is known that RNase L mediates the anti-viral effects of IFNs, and evidence suggests that it may be involved in mediating their anti-tumoral effects as well. An understanding of the biochemistry of RNase L may lead to improvements in treatments of maligancies with IFNs and to insight into the role the enzyme plays in the regulation of "oncogenes" or "proto-oncogenes". We will describe the overall research program and report progress in the construction of a cDNA (complementary DNA) to isolate the RNase Lgene.  ?  99  ?  Name of Presenter: Jarita C. Holbrook Institution: San Diego State University Classification: Graduate Student Major Area of Study: Astronomy NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Professor C. T. Daub  ?  Temperature Mapping of NGC 6572, NGC 6543, and NGC 7662 The wavelengths 5007 and 4363 OIII emission lines of NGC 6572, NGC 6543, and NGC 7662 were observed using the 1 meter telescope at Mt. Laguna and the CCD camera. Our images provide two dimensional resolution of the nebulae at these wavelengths. The images were normalized using the spectroscopic results from other astronomers which automatically corrected for reddening effects. These images were then divided and used to construct the two-dimensional resolution temperature map of each nebula. The Image Reduction and Analysis Facility (IRAF) program developed at Kitt Peak National Observatory was used to reduce the images and perform the arithmetic needed in the construction of the temperature map.  ?  100  ?@  Name of Presenter: Charles Holzer Institution: San Diego State University Classification: Junior Major Area of Study: Mathematical Sciences NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Peter Salamon  ?$  Polygonal Approximation of Human Immune Cell Shape This is a computer program that gives a polygonal approximation of a human immune cell shape. The approximation will be used in classifying the cell shapes into different categories. Past methods of classifying cell shapes are what is called the elliptical shape factor and circularity. These methods compare the cells with an ellipse or circle of approximately the same area as the cells. Finding a polygonal representation of a cell makes it possible to use more parameters in classifying the cells that past+Z,,, methods leave out, such as the number changes of curvature of the cell boundary. Currently the program is being modified so it can give more parameters, and also testing how the polygonal approximation differs when the same cells are oriented differently. It is hoped that this program will give a good estimate of how accurate the polygonal representation is compared to the original cell.  ?  101  ?  Name of Presenter: Maria T. Hurtado Institution: University of California, Riverside Classification: Graduate Student Major Area of Study: Psychology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Lisa Bridges  ?  Relations Among Observed and Parent Report Measures of Infant  ? Temperament A controversy exists as to whether mother report of infant temperament is valid. The present study examined associations between mother report and observational measures of infant temperament, and the influences of birth order and gender differences on these measures. Rothbart's (1978) Infant Behavior Questionnaire and Goldsmith and Rothbart's (1990) Laboratory Temperament Assessment Battery were utilized. Subjects were 71 six monthold (34 male), primarily from Caucasian, middleclass families. Observed anger was related positively to motherreported distress to limitations and negatively to duration of orienting, while pleasure expressions were positively related to duration of orienting and smiling. No sex differences were found, while some birthorder differences were found. Most strikingly, firstborns that were reported by their mothers to be highly soothable were less angry and more positive in the lab, while the reverse was true for laterborns. Overall, our results suggest that motherreport is a valid means for assessing infant temperament.  ?@  102  ?  Name of Presenter: Kimberly Jackson Institution: Wayne State University Classification: Sophomore Major Area of Study: Chemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. C. Poole  ?H&  Investigation of Cera Gas Chromatograph Model 100 Gas chromatography is one of the most prominent and effective separations techniques in the area of analytical chemistry. Young inspiring chemists, at the high school level, should obtain knowledge and become familiar with chromatography. Until now, the instrumentation available was too expensive and too complex for a high school setting. CERA has produced a gas chromatograph, GC,+[,,, which is designed to help future chemists get an early beginning. This instrument will help students develop the concepts of chromatography. The Cera Gas Chromatograph Model 100 is an inexpensive, compact, rugged, analytical instrument specifically designed as a teaching tool for the separation science, gas chromatography. The goal of my project was to evaluate the instrument. The parameters included determining the optimum operating parameters, evaluating how well the CERA MODEL G.C. predicts established chromatographic theory, testing column efficiency, detector response, and to prove this instrumentation is suitable for practical applications.  ?  103  ?H  Name of Presenter: Marcia Jones Institution: Jackson State University Classification: Junior Major Area of Study: Biology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Fred Nelson  ?  The Presence of Esterase Enzymes in Four Newly Established Fish  ? Cell Lines Enzyme assays were run on four new fish cells lines that were established at the Virginia Institute of Marine Science to determine the presence of esterase enzymes. The assays were part of the characterization process required by the American Tissue Culture Collection in order to officially establish the fish cell lines. The AlphaNaphthol AsD Chloroacetate Esterase detection kit and the AlphaNaphthyl Acetate Esterase detection kit (Sigma Chemical Co.) were used. The procedure for both kits involves making cytospins (slides) on which there were two sections containing cells. Slides were examined using a high power light microscope. The number of granules present in a single cell was counted using three categories: 0 granules, 110 granules, and greater than 10 granules. Analysis of the results showed that all the cell lines contained both Chloroacetate and Acetate Esterase enzyme.  ?`"  104  ?#  Name of Presenter: Patrick F. Joyce Institution: University of California, Riverside Classification: Graduate Student Major Area of Study: Biology NSF Sponsored Program: RCMS Faculty Advisor: Dr. Elizabeth Bray  ?0*  Investigation of DroughtStressInduced Genes of Tomato *\,,,ԌAlterations in gene expression occur during drought stress. Four genes that are induced by drought stress have been isolated from tomato. The DNA sequence of the cDNA copies of these genes has been determined. To better understand the function of these genes, plasmids were constructed to be used in the transformation of plants to overproduce and underproduce the droughtinduced gene products. Each cDNA was inserted into the cointegrate vector pMON316 or the binary vector pKYLX71 such that the expression is driven by the constitutive promoter CaMV 35S. Each gene was inserted in both the sense and antisense orientations. This allows for over and underproduction of the gene products, respectively. Agrobacterium lumefaciens strains GV311SE and LBA4404 transformed with these plasmids, will be used to infect cotyledons so that transformed plants can be recovered and used to study the function of the gene products.  ?H  105  ?  Name of Presenter: Lesa Kennedy Institution: City College of New York Classification: Senior Major Area of Study: Electrical Engineering NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Vladimir Petricevic  ?P  Spectroscopic Properties of Cr:CaLaSOAP We have performed basic spectroscopic measurements of  C Cr:CaLa4(SiO4)3O) crystal in order to evaluate its potential for tunable laser operation in the near infrared spectral region. The polarized absorption spectra were measured to identify the best pump wavelengths. Fluorescence spectra were measured for 633,700,830 and 1064nm excitation at room temperture and at liquid nitrogen temperature (77K). The temperature dependence of the fluorescence intensity indicates the presence of strong nonradiative processes at room temperature. The measured values of the emission bandwidth and radiative lifetime will be used to estimate the stimulated emission cross section. The possiblity of using Cr:CaLaSOAP as a tunable solid state laser source for the 12001500nm spectral range will be discussed.  ?!  106  ?,#  Name of Presenter: Jabari Lee Institution: Jackson State University Classification: Sophomore Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Keith W. Johnson  ?(  Computational Simulations of the Electrodynamics in Quantum  ?l) Semiconducting Structures 4*],,,ԌA team in Condensed Matter Physics at the Ames National Laboratory is currently investigating the dynamics of electrons in quantum semiconducting structures in the presence of a static, uniform electric field, by means of computer simulations. In a super lattice structure, consisting of layers of gallium arsenide (a substance of small band gap), and aluminum gallium arsenide (a substance of large band gap), the conduction band, if graphed, would be a periodic square wave. Normally the wave packet in the center well undergoes a cyclic breakdown and reconstruction within the center well. Perhaps what makes this research unique is the implementation of a "jog", a single center well that is slightly shallower than all the others. This jog offsets the cycle. However, the desired effect is to obtain increased periodic dipole movement to greatly enhance power output.  ?  107  ?  Names of Presenters: Juan Martinez and Ruben Enriquez Institution: University of Texas at El Paso Classification: Juniors Major Area of Study: Electrical Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. G. Randy Keller  ?  The Lithospheric Structure of Africa Determined by Surface Wave Dispersion Analysis The analysis of surface wave dispersion is a cost effective method to determine gross lithospheric structure, and the African continent remains as a region where lithospheric structure is poorly known. However, this continent is of considerable interest because of its classic rift and shield structures. The analysis of surface wave dispersion requires intensive data processing, and programs created by Dean and Keller (1991) were utilized in this study. Several propagation paths were chosen for this study based on their azimuths, which must lie within five degrees of the great circle path connecting the stations. The seismograms from these stations were digitized, filtered, and processed using the programs SURWAV and SEISMO. SURWAV was used primarily to prepare the signal for analysis by SEISMO. After being digitized, with data such as time of arrival, time correction, and period, the output is used in the next phase, SEISMO. The data are then filtered by SEISMO and used to create a power matrix, plotted as a function of group velocity and period. This power matrix results in an estimate of the group velocity curve in order to begin the processing. Phase velocity is then derived by phase-matched filtering. This process is then repeated for each signal. The next step involves the cross-correlation of the chosen paired signals. Filtering of this newly created signal produces another power matrix. Group and phase velocity are calculated for each pair of stations. After further processing, several events for each pair of stations are combined to produce overall group and phase velocity dispersion curves through at least squares analysis. These curves are then inverted to produce earth models which approximate lithospheric structures for portions of Africa. In our analysis, we found low group and phase velocities along the East African rift which+^,,, indicate a thin lithosphere. We also found high velocities over most of the remainder of the continent. These velocities are indicative of shield areas.  ?  108  ?x  Name of Presenter: Obed Matus II Institution: University of Texas at San Antonio Classification: Junior Major Area of Study: Mathematics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Shair Ahmad  ?  Sturmian Theory for Second Order Linear Differential Equations Consider the second order Differential Equations y''+a(t)y=0 (1) y''+b(t)y=0, (2) where a(t) and b(t) are continuous on the interval [a,b], and such that b(t)  a(t), with  C b(t0)>a(t0) for some t0  [a,b]. A number b,b>a, is called a conjugate point of a relative to an equation of the form (1) if there exists a nontrivial solution of (1) which vanishes at a and b. We present three statements, in terms of conjugate points, that are equivalent to the well-known Sturm Comparison theorem, which establishes a relation between the zeros of solutions of (1) and the zeros of solutions of (2).  ?  109  ?  Name of Presenter: Lucy McCorkle Institution: Howard University Classification: Graduate Student Major Area of Study: Chemistry NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. F. Ayorinde  ?  Molecules in our Lives: A Resource Manual for Precollege Science  ? Teachers A laboratory manual in chemistry and molecular biology is being designed to aid precollege science teachers in introducing fundamental concepts and techniques to students in five District of Columbia high schools. Volume One, entitled: Molecules in Our Lives, includes activities that reflect the dependence of society on chemical molecules, while at the same time emphasizing basic principles. For example, students are taught how to make aspirin from wintergreen oil. Underlying concepts in these experiments include: chemical reactions, stoichiometric equations, base catalyzed hydrolysis, acid catalysis, limiting reactants, crystallization, etc. Another series of experiments involves the extraction and purification of triglyceride oils from vegetable*_,,, oilseeds, and the synthesis of soaps, nylons and polyesters. Molecular biology exercises include isolation and purification of DNA, RNA and proteins from natural products.  ?  110  ?x  Name of Presenter: Russell McDonald Institution: University of Oklahoma Classification: Junior Major Area of Study: Electrical Engineering/Computer Science NSF Sponsored Program: RCMS Faculty Advisor: Dr. Adedeji Badiru Cantor Search Technique for Artificial Intelligence Systems The work reported in this paper involves a computer simulation experiment to investigate the operational aspects of the preliminary form of the Cantor Set Search technique. The Cantor Set search technique is a new approach for searching for elements in an expert system's knowledge base. Expert system and data base interface, necessary to synthesize the technique into a formal search algorithm, will be discussed. Artificial intelligence is defined as the ability of a machine to use simulated knowledge in solving problems. Expert Systems represent the most successful branch of artificial intelligence to date. The modularity of an expert system is an important distinguishing characteristic. While conventional programs manipulate information, an expert system must adaptively solve problems based on previous data. The efficiency of an expert system depends on the effectiveness of the search technique used to match date to knowledge. The Cantor Search technique is an enhancement that has potential for improving the effectiveness of artificial intelligence systems.  `,,,  ?  111  ?  Name of Presenter: Vaughn McMullin Institution: Virginia State University Classification: Junior Major Area of Study: Mathematics and Physics NSF Sponsoring Program: RCMS Faculty Advisors or Mentors: Eric Frerking and George Henderson  ?  Image Deblurring Using the Fourier Transforms An image is blurred by spatially convolving a matrix with a kernel, which mathematically represents system responses which causes the blurring. It can be blurred the same way by using a Fourier transform algorithm. The algorithm consists of transforming the image and then multiplying the transformed image with the transform of a kernel. To deblur the image the procedure is to divide the transform of the image by the transform of the kernel. Since the Fourier transform algorithm and the convolution return the same blurred image, then this deblurring technique can be used to deblur any image if the kernel is known. If the kernel is too complex then the quotient can be become illconditioned when trying to deblur it and then other techniques must be used.  ?  112  ?  Name of Presenter: Angelette Mealing Institution: Talladega College Classification: Senior Major Area of Study: Mathematics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: William Smith  ?  Structure of the Midgap Electron (EL2) Trap as Determined from the Electrical Activation of Silicon Implanted in Gallium Arsenide  ?  (GaAs) Several models describing the electrical activation of silicon implanted in Semi Insulating Gallium Arsenide (SI GaAs) were studied with particular emphasis on the reaction of silicon with EL2 present in the substrate. Experimental data obtained by Brierley et al have demonstrated a relation between silicon donor activation efficiency and substrate concentration of EL2. An attempt was made to fit the models of this data to an activation curve covering a range of silicon concentration with the aim of determining the atomic structure of EL2.  ?H&  113  ?'  Name of Presenter: Vanda W. Merriman Institution: Massachusetts Institute of Technology Classification: Freshman Major Area of Study: Accelerator Physics NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. W. Wade Sapp+a,,,Ԍ ? ԙ Precision Magnet Alignment for Charged Particle Beams The MITBates Linear Accelerator is presently installing a new stretcher/storage ring, which will facilitate nuclear research with high duty factor extracted electron beams. The ring also provides stored beam for internal targets for further nuclear study with a beam of energy of up to 1 GeV. The installation of this ring requires the placement of dipole and quadrupole magnets, numbering over 200 in all, to a precision on the order of 100um of their ideal position. Very high precision optical surveying equipment, generally with electronic readout, is employed. Highly automated data acquistion, analysis and error computations are performed mostly on PCs. Other analysis and documentation which assisted the physics staff was performed on VAXVMS systems. The results to date will be presented as well as a discussion of the applicability of this data acquisition and analysis techniques to other scientific and technical areas.  ?  114  ?h  Name of Presenter: Crystal Moffett Institution: Clark Atlanta University Classification: Junior Major Area of Study: Biology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Isabella Finkelstein  ?  Isolation of Extracellular Polysaccharide Flocculents from  ? Cyanobacteria Mats Mixed microbial mats dominated by filamentous cyanobacteria (Oscillatoria sp) have been shown to detoxify heavy metals and other toxic chemicals from polluted sites. It has been proposed that one of the mechanisms of metal sequester involves secretion of extracellular flocculents which bind and precipitate heavy metals from solution. The objective of this research is to investigate the nature of bioflocculents produced by cyanobacteria mats. The results show that a heterogenous mixture of polysaccharides activity was detected by alcian blue binding assay. The subpopulation of exopolysaccharides which show highest flocculating activity had molecular weights greater than 200,000 daltons and uronic acid content of more than 30% of the total glycosyl residues. It is suggested that uronic acids may play a role in metal binding by cyanobacterial polysaccharide flocculents.  ?$  115  ?H&  Name of Presenter: Franklin Monzon Institution: Princeton University Classification: Senior Major Area of Study: Electrical Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Mansour Shayegan  ?+  Mobility Anisotropy in Two-Dimensional Hole Gases +b,,,ԌSeveral Hall-effect bridges were fabricated on GaAs/AlGaAs (311)A heterojunctions containing two-dimensional hole systems. Magnetotransport experiments were carried out to measure the density and mobility of these systems. The purpose of the experiments was to study the anisotropic mobility, and it was found that the anisotropy increases with increasing hole density. These experiments are part of a research effort involving materials used for optoelectronic devices.  ?  116  ?`  Name of Presenter: Vern Nozie Institution: Northern Arizona University Classification: Sophomore Major Area of Study: Forest Entymology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Michael Wagner The Effects of Slash Size on Moisture Content and Ips Infestation in Ponderosa Pine Infestation by Ips lecontei is a problem in Ponderosa Pine slash that can lead to infestation of live trees. Although various studies have been done in Arizona, none have focused on the role of moisture content. This research has been to take moisture content readings on bolts and poles which have different lengths and diameters to determine the relationship between slash size and moisture content. A simultaneous study examines the relationship between slash size and Ips infestation. The results show that the length and width of slash does affect moisture content readings as the slash dries. This study establishes the rate of drying. The data has shown that as the moisture content level drops the Ips infestation accelerates.  ?   117  ?  Name of Presenter: Miria F. Otero Institution: Pennsylvania State University Classification: Junior Major Area of Study: Biology NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. T. Hollis  ?(#  Basement Membrane Thickening in Diabetic Rats Diabetic individuals who have had the disease for a prolonged period of time develop an abnormal condition in the retina called diabetic retinopathy. This condition is the leading cause of blindness in persons 2574 years of age and is caused by increased vascular permeability of the retinal capillaries. Previous investigations have shown that basement membrane thickening (BMT) is associated with increased vascular permeability, and that antihistamines reduce BMT. We treated streptozotocindiabetic male SpragueDawley rats with the antihistamine hismanal. Animals were divided into three groups: control, insulin diabetic and hismanal. +c,,, The retinal inner plexiform layer was sectioned and examined under the transmission electron microscope to measure capillary basement membrane width. Differences between capillary basement membranes (CBM) is being observed to determine if the antihistamine hismanal can reverse BMT in experimental diabetes.  ?x  118  ?  Name of Presenter: Martin L. Panchula Institution: Iowa State University Classification: Junior Major Area of Study: Material Science & Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Steve Martin  ?  Damage to Optimal Glass Fibers used in Nd:YAG Lawser Surgery The use of optical fiber lasers is revolutionizing surgical practices, however physical and chemical degradation at the tip of the optical fiber is still problematical. Moreover, any damage so incurred only compounds the rate at which further damage accrues. Four different ratios of laser power (power transmitted through the tip after surgery on chicken meat divided by that transmitted before) were monitored as the response variables indicative of four aspects of tip damage. Their dependences on selected control variables were studies with a statistically designed experiment, the selected control variables being the power setting of the laser, the time of contact with tissue and the number of contact cycles used during the surgical simulations. The results are presented as response surfaces plotted versus power setting, contact time and the number of cycles taken in appropriate pairs. These surfaces reveal the extent of damage to expect in any subrange studied as well as which combinations of settings should minimize tip damage.  ?x  119  ?  Name of Presenter: Roderick Pearson Institution: Jackson State University Classification: Senior Major Area of Study: Physics NSF Sponsored Program:RCMS Faculty Advisor or Mentor: Dr. Keith W. Johnson  ?%  Barycentering Time Corrections for Gammaray Sources A key to identifying a possible gammaray pulsar is to determine the periodicity of the source. The data gathered during observations are the arrival times of gammarays as they reach the telescope from the source. For the most precise measurement of possible signals the arrival times for the source must have a variation in time on the order of microseconds for a minimum period of one celestial year. This precision is achieved by correcting+d,,, the times for variations caused by the motion of the earth in its orbit of the Sun. The Doppler, shift caused by the motion of the earth as it orbits must be eliminated. Relativistic effects caused by gravitational differences between the earth and sun have to be considered. The time delay variable caused by the rotation of the earth must be identified. Correcting for these factors should yield arrival times that do not vary by as much as the order of microseconds.  ?  120  ?(  Name of Presenter: Roy Pemberton, Jr. Institution: Hampton University Classification: Junior Major Area of Study: Marine Science NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Robert Jordan  ?  Preliminary Observations of the Occurrence of Bottlenose Dolphins  ?h in the Lower Chesapeake Bay Twentysix small boat cruises were conducted in the lower Chesapeake Bay from May 21 through August 7, 1992, to document occurrences of bottlenose dolphins. A total of 257 dolphins were observed during 21 sightings (x=12.2 dolphins per sightining, range = 130). The Cape Charles and Cape Henry subareas produced the most sightings per unit effort and had the largest pod size (17 and 14.4 respectively). The Hampton Roads subarea included pods that were typically smaller (x=5.2) and more scattered. This study is continuing to determine longterm patterns of habitat usage, movement, and social characteristics.  ?X  121  ?  Name of Presenter: Michael L. Penn, Jr. Institution: Morehouse College Classification: Junior Major Area of Study: Biology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Professor Harvey F. Lodish  ?`"  The Role of Transforming Growth FactorType II Receptor in the  ?(# Growth Inhibitory Activity of the Transforming Growth FactorB1 Transforming Growth Factor B1 is a 25kD polypeptide which affects growth inhibition in a variety of cell types. Numerous carcinomas have lost sensitivity to TGFB, which is linked to the loss of the Type II receptor. My experiments involve transfecting several type II receptordeficient cell lines with the gene for its expression, and using two different assays to determine whether a response to TFGB can be generated. Preliminary results suggest that the presence of the Type II receptor in EJ (human bladder carcinoma), SW480 (human breast carcinoma), and N2A (mouse neuroblastoma) cell lines was not sufficient for TGFB sensitivity. The receptor might+e,,, not be compatible with the signaling mechanisms within cell lines tested.  ?   122  ?  Name of Presenter: Mauricio Portillo Institution: Univ. of Texas at El Paso Classification: Senior Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Dwight Russell  ?(  Monte Carlo Simulation of Alkali Metal Surface Enrichment Caused by  ? Electron Bombardment of Alkali Halides The simulation of alkali metal enrichment at the (100) surface is done by using a theoretical model of defect diffusion in a LiF crystal lattice. A three dimensional grid space represents the halogen and alkali sublattices of an electrically neutral LiF crystal. Electron irradiation occurs before the simulation begins and time is taken as zero from this point. Enrichment of Li at the surface is theoretically caused by diffusion of F-centers, which are electrons trapped in halogen vacancy sites. The creation of F-centers occurs right after electron bombardment. F-center diffusion is then simulated using an initial distribution model and conditioned diffusion in grid space. The Monte Carlo method allows for F-center random motion in the grid space. When F-centers reach the surface of the crystal, they recombine with Li cations to produce metal at the surface. Further details of the model such as time factors and boundary conditions will be discussed. Results of the simulation will be compared to experimental findings.  ?  123  ?   Name of Presenter: Andrew Quam Institution: Northern Arizona University Classification: Freshman Major Area of Study: Forest Health/Biology NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Aregai Tecle  ?!  The Effects of Mistletoe Infestation on the Growth of Juniper This research project studies the effect of mistletoe infestation on the growth of juniper by answering the following questions: Would there be a change in the growth rate and health of juniper trees (Juniperus monosperma) when mistletoe shoots have been pruned? Upon removal of mistletoe shoots, would the juniper tree maintain adequate recovery in respect to health and vigor? Do heavilyinfected versus slightly infected trees have reduced growth rates? Does removal of heavilyinfected trees provide a means of mistletoe suppression? Temporary reduction in spread of mistletoe may be accomplished by breaking or pruning off mistletoe shoots; this procedure would require repetition at what periodic intervals? These questions will be answered with a study of paired infected+f,,, trees on the lands of the Zuni Pueblo. The effects of removal of all mistletoe infected branches from one of each pair will be studied for a three year period.  ?  124  ?x  Name of Presenter: Kenya Rambeau Institution: Howard University Classification: Freshman Major Area of Study: Chemical Engineering NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Joan M. Frye  ?  High Resolution Infrared Laser Spectroscopy of "Cold" Molecules Infrared laser absorption spectroscopy of transient molecules has been confined to relatively small (34 atom) species. This is due to the fact that higher molecular weigh molecules yield very congested spectra that are often difficult if not impossible to assign. Supersonic expansion of a gas can lead to a rotational temperature on the order of a few degrees Kelvin, resulting in significant simplification of the spectra. A supersonic molecular beam apparatus incorporating a pulsed slit nozzle, 5 mm long, 100 microns wide, has been assembled in this laboratory, and a tunable infrared diode laser has been used to  C probe the extent of rotational cooling in C02 seeded in He. Preliminary results on the backing pressure, seeding ratio, and spatial dependencies will be presented.  ?  125  ?\  Name of Presenter: Rebecca O. Ramirez Institution: University of Texas at El Paso Classification: Senior Major Area of Study: Geological Sciences NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Philip C. Goodell  ?  A Reconnaissance Study of the Electron Energy Band Gap in the  ?! PbS-Sb2S3 Sulfosalt Mineral Join This study focused on the electron energy band gap for semiconductor. Electronic semiconductors are materials which occupy an intermediate position between the highly conducting metals and the nonconducting materials, such as insulators. To understand the electrical properties of solids, the behavior of the electrons in electron energy levels arranged in bands are studied. Between these bands, a forbidden energy region, referred to as the energy gap (Eg) exists. The electron occupancy in the bands and the width of the energy gaps determine whether a solid material is a conductor, semiconductor, or insulator. *g,,,ԌThis investigation was pursued knowing that the mineral galena, PbS, was one of the first minerals to be used as a semiconductor. Some semimetal chalcogenide containing PbS are also minerals are also potential semiconductors. In 1989, the energy gaps in the minerals boulangerite, dadsonite and jamesonite were experimentally measured and determined to be semiconductors. In contrast to direct measurement, three methods to calculate the width of the energy gap have been proposed in the literature: 1) the band gap variation with chemical composition method, 2) the density variation method, and 3) the atomic weight-valence number variation method. The three methods of calculation of the energy band gaps were compared with values measured for the PbS-Sb2S3 join.  ?  126  ?  Name of Presenter: Phillip Lamont Redrick Institution: Morehouse College Classification: Junior Major Area of Study: Chemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Morris Waugh  ?  Approaches to Enzyme Mediated Synthesis of Porphyrins The synthesis of 2aminomethyl pyrrole 1 and 2aminophenyl pyrrole 2 are reported. Pyrrole 1 was prepared by hydrogenation of the oxime of pyrrole2carboxaldehyde. In an analogous manner 2 was obtained by hydrogenation of the oxime of 2benzaylpyrrole. These amines are expected to serve as substrates for a porphobillinogen deaminase catalyzed synthesis of mesoporphyrins.  ?  127  ?X  Name of Presenter: Hue Rhodes Institution: Princeton University Classification: Sophomore Major Area of Study: Civil Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Ahmet Cakmak  ?  Structural Analysis of the Hagia Sophia In the sixth century, the emperor Justinian constructed the Hagia Sophia in Constantinople. For eight hundred years it stood as the largest vaulted structure in the world. I am helping to build a computer model of the Hagia Sophia. We have attempted to accurately replicate the phases of construction in our model. Using primary sources such as drawings by Van Nice, I have measured the deformations of various parts of the structure validate our model. We have experimented with different values for the moduli of elasticity and Poisson's Ratio, for brick, mortar, and stone. Using recorded earthquake data from the area, I have helped study the dynamics of the structure to match the building's natural frequencies and earthquake response. Once the model is complete, we will be able to predict behavior under seismic loads. We will+h,,, then recommend modifications and reinforcements to improve durability and prevent collapse.  ?   128  ?  Name of Presenter: Kimberly N. Rice Institution: Spelman College Classification: Senior Major Area of Study: Mathematics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Robert Parker  ?(  Analysis of Map Projections with Function of a Complex Variable The ordinary system of parallels and meridians used as a basis for drawing a map on a flat surface is a map projection. My study concerns the use of complex functions one can easily take a point off the map and find its latitudelongitude coordinate on the earth's surface. Because complex functions provide a simple way to give exact expressions for these mappings, we are studying them to construct an inverse allowing us to create transformation in the reverse order.  ?  129  ?  Name of Presenter: Matt Rivas Institution: Iowa State University Classification: Senior Major Area of Study: Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Bion Pierson  ?  Numerical Method Comparisons for LowThrust Optimal Trajectories  ?X with Gravity Aaaist The advantages of lowthrust trajectories are well known, but it may be possible to improve these savings by using an orbital maneuver called a gravity assist or hyperbolic encounter. Two method types, direct and indirect, are compared in three test problems to assess each method's ability in solving optimal trajectories; both require the numerical solution of a constrained parameter optimization problem. The test problems treated are the class van der Pol problem, a lowthrust Mars mission, and a lowthrust Earth escape. The two lowthrust test problems were chosen to facilitate the solution of the main problem of finding an optimal lowthrust trajectory for an Earth escape with a lunar gravity assist. A detailed computational comparison based on the test problems and preliminary results for the lunar gravity assist will be presented.  ?h)  130  ?*  Name of Presenter: Marchant D. Rolle Institution: Pennsylvania State University+i,,,ԌClassification: Sophomore Major Area of Study: Ecotoxicology NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. W.A. Dunson  ?  Effects of Low pH, Temperature, and Individual Concentrations of Cu, Pb, Al and Zn on the Embryonic Development of the Jefferson Salamander, Ambystoma Jeffersonianum This experiment examined the toxic effect of low pH, temperature and individual concentrations of Cu, Pb, Al and Zn on the embryonic development of the Jefferson salamander, Ambystoma jeffersonianum. Acute exposure to water pH's 4.00 to 6.00 did not significantly increase mortality, while chronic exposure caused significant mortality at pH 4.5 and below. Survival at chronic low pH was significantly less at 10$C than at 15$C. Low pH increased the time until hatching and decreased hatching success. Hatching was initiated much faster in the 15$C treatments than that in the 10$C treatments. The most toxic metal to the embryos, Cu, had a mortality in the lowest concentration, 125 ug/l within 14 days. Al, Pb, and Zn did not significantly affect embryonic mortality at low pH. In the future studies will be conducted to better understand why Pb and Al affect the Jefferson salamander the way it does.  ?P  131  ?  Name of Presenter: Ericka Russell Institution: Pennsylvania State University Classification: Junior Major Area of Study: Chemistry NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Ayusman Sen  ?X  Synthesis, Characterization and Catalytic Activity of Palladium Containing Polymer Films The objective of the present research is the study of stable polymertrapped metal nanoclusters of welldefined sizes.  C@ Nanoclusters with sizes ranging from 1 to 10 nm (1 nm = 1 x 10é9m) represent a new class of materials with unique properties that are different from those of discrete molecules, as well as bulk solidstate materials. Our approach involves the synthesis of the clusters in isolated pockets in the polymeric matrix, and one way we achieve this is by prebinding the metal precursor to specific sites on the polymer. Typically, a palladium compound, together with the appropriate polymer, was dissolved in a suitable solvent and the resultant solution was used to cast films. Following thermal curing to remove the solvent and reduce the palladium to the metallic state, black or brown freestanding films were obtained. These were characterized by a variety of physical techniques. The polymertrapped palladium nanoclusters were found to catalyze the hydrogenation of a variety of olefins under mild conditions.*j,,,Ԍ  ?  132  ?X  Name of Presenter: Louis Sanchez Institution: University of Texas at San Antonio Classification: Senior Major Area of Study: Computer Science NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Kay Robbins  ?  An Empirical Study of a Cooperative Strategy for the Solution of  ? the Traveling Salesman Problem The theory of cooperating processes relies on the development of a diverse and independent set of agents. Agents report on partial success so that other agents can use this information to improve their own solutions. By exchanging hints, the solution space that each agent must search is reduced. For a wide class of problems, there is a highly nonlinear increase in performance due to these interactions. We have applied the theory of cooperating processes to the Traveling Salesman Problem in a distributed environment. All hints are written to a central blackboard that can be accessed by all agents for obtaining hints and posting results (new hints). This arrangement can be implemented on one or several computers. We compare the performances of three different strategies for solving the Traveling Salesman Problem: noncooperating agents each using a random generate and test strategy with no blackboard, noncooperating agents each with its own private blackboard, and cooperating agents interacting through a central blackboard. For each approach the average solution time (over twenty runs) of first finishers for 1, 2, 3, 4 and 5 agents are computed and plotted.  ?  133  ?X  Name of Presenter: Alexis M. Scott Institution: Spelman College Classification: Senior Major Area of Study: Mathematics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. J. D. Crawford  ?  Nonlinear Dynamics and Chaos Nonlinear dynamics is an important subject in both mathematics and the physical sciences. The inclusion of nonlinear effects introduces phenomena not found in linear differential equations. The damped driven oscillator (in this case the pendulum) is an interesting example. In this work, the timeasymptotic behavior of the pendulum is analyzed as the external forcing strength, A is varied. As A is increased, different bifurcations in the bifurcation diagram can be observed. These bifurcations include: pitchfork bifurcation (involving symmetrybreaking); period doubling bifurcations; period doubling cascades which lead to chaotic behavior;and crisis bifurcations of chaotic attractors. Numerical results include bifurcation diagrams, images of phase space attractors, and time series. This research was made possible+k,,, through joint efforts of both Spelman College in Atlanta, Georgia and the University of Pittsburgh in Pittsburgh, Pennsylvania.  ?X  134  ?  Name of Presenter: Aliyah Shakoor Institution: Wayne State University Classification: Freshman Major Area of Study: Chemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Joeseph S. Francisco  ?`  An Investigation of Atmospheric Chemical Kinetics The overall goal of my research group is to understand atmospheric chemical kinetics relating to the ozone layer. We investigate atmospheric chemical kinetics through experiments and computations. We also try to propose alternate CFC's or chlorofluorocarbons. We do this because we have found that certain halocarbons deplete the ozone layer. My specific duty in the laboratory is to perform the calculations on CF3CO. This is a by-product of CF3COH that is produced in the troposphere. I do ab-intio quantum mechanical calculations using a GAUSSIAN-90 computer program. I also do calculations on CH3OCH2Cl, which is a halengenated dimethyl ether, to see if it is an appropriate halocarbon for the atmosphere.  ?  135 Name of Presenter: Wilson J. Sheppard Institution: Southern University Classification: Junior Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Diola Bagayoko  B   Cohesive and Magnetic Properties of Free AL18Fe Clusters  ? Diana Guenzburger and D. E. Ellis_ Diana Guenzburger and D.E. Ellis, Phys. Rev. Lett. 67, No. 27,3832, December 1991._ recently posed the question whether or not iron impurities in aluminum are magnetic. We  CC present some answers to this question. We considered free Al18Fe clusters, in the fcc geometry, at lattice constants varying from 7.0 a.u. to over 8.0 a.u. Our calculations employed a local density potential in the linear combination of Gaussian orbital formalism. Other salient features of our method include the provision for polarization orbitals on the aluminum atoms and the inclusion of diffuse orbitals to properly describe charge redistribution. We performed abinitio and self consistent computations. We found the iron impurity to bear a small local magnetic moment (0.14 Bohr Magneton) that vanishes as the lattice  C' parameter is reduced. Free Al18Fe clusters are stable at a lattice constant around 7.635 a.u.  ?;*  136 +l,,,Ԍ ?  Name of Presenter: August L. Smith III Institution: University of California, Riverside Classification: Senior Major Area of Study: Physics NSF Sponsored Program: RCMS Faculty Advisor: Dr. Richard Seto  ?x  Optimization of Event Detection in PhiParticle Decay Collisions between heavy ions, such as gold on gold, traveling at relativistic speeds, can be used to test the validity of the standard model, which includes the quark model. The prediction of this model is the creation of the phiparticle, a strange quark with an antistrange quark, during collisions of the large nuclei. The phiparticle decays into a plus kaon and a minus kaon particles of similar properties but of opposite electric charge. Detection of the kaons in collisions experiments can support theory. The detectors used to detect an event, or phiparticle production, should be positioned to maximize the probability that the kaons enter the detectors. This requires that differential cross sections for the center of mass of the kaons be transformed to cross sections for the laboratory frame. The cross section is integrated by a computer to give the probability that the kaons have entered the detectors. Histograms of the results will give visual aid to determine optimal detector positioning.  ?  137  ?p  Name of Presenter: Michael Spears Institution: University of Oklahoma Classification: Graduate Student Major Area of Study: Electrical Engineering NSF Sponsored Program: RCMS Faculty Advisor: Dr. J. Sluss  ?  PolymerDispersed Liquid Crystals Polymerdispersed liquid crystal (PDLC) films are composed of liquid crystal microdroplets dispersed throughout a polymer matrix. PDLC's are a unique system in which light scattering from submicron size nematio liquid crystal droplets in a polymer host can be electrically controlled. They are promising materials for light control and electrooptic applications because they can be switched electrically from a light scattering "offstate" to a highly transparent "onstate." Of special concern in most applications of PDLC films, such as electronic information displays, is their ability to offer good electrooptic performance over extended ranges of temperatures as well as their environmental stability. This investigation was carried out in order to characterize newly synthesized PDLC materials that held the promise of improved switching times and lower threshold voltages. 0*m,,,ԌThe research consisted on analyzing the light transmission and scattering of PDLC samples while under the influence of an electric field.  ?  138  ?x  Name of Presenter: Shawna St. Julein Institution: University of Texas at San Antonio Classification: Junior Major Area of Study: Mathematics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Ming-Ying Leung  ?  Computational Analysis of DNA Sequences Using the Intellgenetics  ? Suite Genalign, a sequence alignment program in the Intellgenetics suite was applied to a query of viral sequences. The sequences were retrieved from the databank, GenBank. The results showed that the run time increased cubically with the sequence length. Further analysis indicated that even if the memory capacity is increased, it is inefficient to run multiple genomic sequences with Genalign. However, the "match" program developed by Leung et al. utilizes an algorithm in which the average memory and the run time requirement both increase almost linearly with the total sequence length and is very efficient in aligning multiple genomic sequences.  ?  139 Name of Presenter: Courtney St. Prix Institution: City College of New York Classification: Senior Major Area of Study: Chemistry NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Daniel L. Akins  ?  Spectroscopic Methods of Adsorbed Spectral Sensitizer Detection and  ?x Characterization  C The absorption spectrum of 2,21ĩcyanine acquired by using a Perkin Elmer uv/visible spectrophotometer is measured to obtain absorption  C! maxima. The Raman spectrum of 2,21ĩcyanine, adsorbed onto a silver electrode, was obtained by using a uv/visible laser and a three electrode electrochemical cell. By varying the conditions of pH, concentration, and electrode potential, the presence of the aggregate, polycrystallite, and monomeric forms of the adsorbate was confirmed. Also, a discussion is provided of the theory of spectral sensitization and how it extends the spectral responses of photoconductors to wavelengths longer than the conductor's intrinsic response.  ?8*  140 +n,,,Ԍ ?  Name of Presenter: Tiffany Staples Institution: Wayne State University Classification: Sophomore Major Area of Study: Biochemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Robert Arking  ?x  Multiple Physiological Mechanisms Underlying Extended Longevity in  ?@ Drosophila A number of independent labs have successfully selected for postponed senescence in Drosophila melanogaster. Now that several long-lived fly strains have been created, the major concern of aging studies is to identify the genes and physiological mechanisms responsible for extended longevity. Data in literature suggests that long-lived flies have greater energy reserve and thus are more resistant to stress. The objective of our experiments was to test these assumptions in our strains with regard to lipid content and starvation resistance. Our results indicated that our two independently derived strains had a lower lipid content than control strains. Furthermore, there was no statistical correlation between lipid content and starvation resistance. These results suggest that our strains are utilizing physiological mechanisms different from other labs. This finding indicates that multiple avenues exist for creating long-lived flies.  ?  141  ?  Name of Presenter: Leslie Stoneham Institution: Texas A&M University Classification: Freshman Major Area of Study: Computer Science NSF Sponsored Program: RCMS Faculty Advisor: Dr. S. Bart Childs  ?   Literate Programming for Scientific Codes Donald Knuth's goal in literate programming is that we explain to a reader what a computer should do as well as communicating that to the computer. Knuth's WEB is the merging of structured programming and structured documentation and is the seminal literate programming system. It produces a program for compilation and typeset description of the program.  C(# WEB uses TEX and is therefore easy to include mathematics in its description of the models. For example, a springmassashpot system is: ?" + x' + x = sin (t) Imagine saying that in program comments? A scientific literate programming system could assist in overcoming the semantic gap between the formulation of mathematical models of physical systems and the codes that represent their solution by showing equations in an elegant presentation.*o,,,ԌFurthermore, a WEB system could be developed to accommodate the several languages and array of computer systems common to scientific computing. Overall, we believe that literate programming offers an opportunity to decrease the cost of developing and maintaining scientific codes because of their readability.  ?@  142  ?  Name of Presenter: Mitchell Suarez Institution: Iowa State University Classification: Sophomore Major Area of Study: Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Bion Pierson  ?H  A Comparison of Numerical Methods for a Class of Rocket Launch  ? Trajectory Optimization Problems Both maximum horizontal speed and maximum range trajectories are obtained numerically for a singlestage rocket launch vehicle flying in a vacuum with uniform gravity. Constant thrust and constant thrust acceleration propulsion modes are examined. A computational comparison among three optimization methods and several method modifications is in progress. An analytical solution has been obtained for one of the optimal trajectory problems; this solution can be compared directly with the numerical solutions. All three methods have the advantage that gradient information is not required. The overall objective of this study is to develop a reliable and efficient numerical method which can later be applied to more difficult trajectory optimization problems which do not admit analytical solutions.  ?X  143  ?  Name of Presenter: Tracy Swint Institution: Alabama A&M University Classification: Senior Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Paul Ebert (LLNL), Rather Brown (AAMU)  ?`"  Light Diffraction Off an Opaque Sphere The diffraction of light by an opaque sphere from an extended xray source focused to a central bright spot behind the sphere has been a curiosity ever since Arago demonstrated the phenomenon in 1818. Although imaging with opaque sphere is not a new idea, it has never been fully developed either analytically or experimentally. The goal of this project is to verify experimentally that an opaque sphere can be used as an imaging element for xrays. An xray system was developed and the bright spot behind the sphere located.  ?+  144+p,,,Ԍ ? ԙ Name of Presenter: Maceo Thomas Institution: University of Maryland, Baltimore County Classification: Senior Major Area of Study: Biochemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Martha Vestling Fenselau  ?x  Localizing the Carbohydrate Attachment Sites in Chicken EggYolk  ?@ IgG (IgY) The goal of this project is to characterize the constant region of the heavy chain (Fc) of chicken eggyolk immunoglobin G, which is called IgY. This large glycoprotein (170,000 daltons) provides immediate early immune protection for the newborn chicks. IgY is known to differ from mammalian IgG in molecular weight (150,000) and in affinity for the glucose/mannose lectin Concanavalin A1. Mammalian IgG bind to the lectin with varying affinity. IgY has no affinity for the immobilized lectin. The protein sequence of the Fc region of IgY has been deduced from cDNA2, however, the sites of carbohydrate attachment are not known. The Fc region is prepared from the complex molecule using papain digestion followed by affinity and size exclusion chromatography. It is cut into peptides by digestion with trypsin, and Nlinked carbohydrate chains are released by endoglycosidase F. Products are characterized by retention times in high pressure liquid chromatography and by molecular weights obtained using laser desorption and electrospray mass spectrometry. Molecular weights and retention times of glycosylated peptides change dramatically when the carbohydrate chains are removed and allow asparagine attachment sites to be recognized.  ?  145  ?  Name of Presenter: Paul Thomas Institution: Clark Atlanta University Classification: Junior Major Area of Study: Chemistry NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Isabella Finkelstein  ?  Infrared Spectroscopy of Drug/DNA Complexes One of the most selective techniques for the study of the binding of drugs to DNA is vibrational spectroscopy. For studies carried out in aqueous solution, infrared spectroscopy has typically not been used because of the strong absorbance of water. Resonance Raman spectroscopy has been used with great success for such investigations, but the spectral changes which are observed are those associated with the drug, not the DNA. Recent studies using infrared spectroscopy for two drug/DNA complexes, ethidium bromide/DNA (EtBr/DNA) and copper tetramethylpyridyl porphyrin/DNA Cu(TMpyP4), have demonstrated changes in vibrational frequency associated with the DNA. The EtBr/DNA complex results in a much smaller shift of the vibrational absorptions associated with the phosphate group of the DNA than does the Cu(TMpyP4)/DNA complex. This indicates that the coulombic interaction between the porphyrin+q,,, and the DNA phosphate group is much stronger than that between ethidium and the DNA phosphate group.  ?   146 Name of Presenter: Sandra Thorpe Institution: Southern Illinois University Classification: Senior Major Area of Study: Chemistry NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. James Hunsley  ?(  Erwinia Amylovora ExtraCellular Polysaccharide (EPS)Derivatized  ? Microbeads as Probes for Apple Lectin Activity Bacterial EPS is believed to play a major role in the pathology of fireblight disease of apples and similar species. Apple cultivars behave very differently in their susceptibility to this disease. To determine the role lectinlike proteins may play both in fireblight infection and resistance, the surfaces of microscopic plastic beads were chemically modified with EPS and other carbohydrates. Extracts of apple tissues were surveyed for their ability to agglutinate these beads.  ?  147 Name of Presenter: Shawn Turner Institution: Southern Illinois University Classification: Sophomore Major Area of Study: Biology NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Marian Smith  ?  Effects of Soil Moisture and Nutrient Status on Germination and  ?X Growth of Boltonia Decurrens Boltonia decurrens, a member of the Asteraceae, is on the Federal list of threatened species, mainly due to major changes in flood patterns in the Illinois River floodplain. This study had two objectives: 1. to determine the effect of spring flooding on seed germination; and 2. to determine the possible effect on seedling growth of an annual replenishment of soil nutrients by floodwaters. Seeds germinated better on standing water when compared to moist or dry soil surfaces; and seedling growth rate and biomass were higher on soil with a nutrient flush. Radiation Damage Studies for the SDC Electromagnetic Calorimeter  ?H& 148 Name of Presenter: Billy J. Vegara Institution: Southern University Classification: Senior Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Diola Bagayoko and Ali Fazely+r,,,Ԍ ? ԙ Radiation Damage Studies for the SDC Electromagnetic Calorimeter Scintillator tiles manufactured by Bicron Corporation were tested for resistance to radiation damage and optical uniformity. The  C  tiles were exposed to 1 Mrad of gamma rays from a 60Co source. The best scintillator samples recovered to about 95 percent of their original light yield. For optical uniformity studies, tiles were grooved and fitted with a 1 mm diameter green wavelength shifter  CD fiber. A 106Ru beta source was used to measure the pulse height for each tile. The best uniformity was achieved when the groove was very close to the edge of the tile.  ?0  149 Name of Presenter: Felicia Walker Institution: Oklahoma State University Classification: Graduate Student Major Area of Study: Solid State Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: S. W. S. McKeever  ?8  Dependence of the Thermoluminescence Properties of LiF: Mg, Cu, P  ? on Impurity Concentration. We have examined the dependence of several of the thermoluminescence (TL) properties of LiF: Mg, Cu, P on the concentrations of the various impurities present in the specimens. The samples were powders grown at the Ben Gurion University (Israel). The properties that we have examined include the sensitivity of the main dosimetry peak, the size of the high  C@ temperature TL peaks (>250oC), the spectrum of the emitted light and the computed trapping parameters (E and S). The data obtained indicate that optimum values for various impurity species can be clearly demonstrated. The greatest sensitivity is  C, achieved using concentrations of Mg, 0.2: Cu2+, 0.002: and P, 3.0 C 5.0 (all M%). If Cu+ is used instead of Cu2+ a concentration of 0.004M% is required. The largest ratio of the dosimetry peak to  C the peak at 270oC is obtained at Mg, 0.2: Cu2+, 0.002; and P 2.0M%. In all samples a deep trap was present, giving rise to a TL peak at  C 390oC. The emission spectrum was observed to be largely invariant with impurity concentration, as long as P is present. Phosphorous appears to be the major luminescence activator. The trapping parameters were evaluated by using computerized least squares fitting. A notable difference to previous evaluations of this type was the inclusion of a temperature dependence for the frequency factor. For the main dosimetry peak a large E value (>2.0 eV) was obtained for those samples for which this peak was intense. Possible interpretations are discussed. Supported by NSF Grant No. RII9014688.  ?)  150 Name of Presenter: Wilbur Walters +s,,,ԌInstitution: Jackson State University Classification: Sophomore Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Keith W. Johnson  ? Synthesis and Modifications of a High Temperature Superconductor A sample of YBa2Cu307(Y123), a superconductor at 90 K, was synthesized from Y203, BaCO3 and CuO powders. The sample was prepared by a frequent grinding and heating process. During the preparation stage an impurity phase known as the green phase (Y2BaCuO5) was encountered, but repeat grinding and heating destroyed the impurities. An x-ray diffraction scan indicated a single phase orthorhombic material which compared favorably to previously documented superconducting samples. The Y123 was mixed with hydrogen peroxide (H2O2) at various aqueous concentrations and various time periods to study the influence of the reaction on the crystallographic and superconducting properties of the Y123. The x-ray diffraction scans showed an increase in BaCO3 and CuO impurities as reaction time increased. Magnetic properties were obtained from a SQUID (Superconducting Quantum Interference Device) magnetometer and resistivity results were also obtained for the samples to determine their superconducting properties.  ?P  151 Name of Presenter: Aundrea Warren Institution: Southern Illinois University Classification: Senior Major Area of Study: Biology NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Paul Wanda  ?X  Recombinant Plasmid Detection by lac Gene Activity A fragment of DNA, 2295 bp, derived from endonuclease restriction of the plasmid pBR322 was inserted into the multiple cloning site of the plasmid pUC19. Insertion of DNA into the multiple cloning site inactivates the alphapeptide of betagalactosidase providing a means of selection for cloning DNA restriction fragments. Without insertion, betagalactosidase activity is detected by inducing the lac promoter with the inducer, sopropylthiogalactoside (IPTG), and plating in the presence of the chromogenic substrate, 5bromo4chloro3indolylbetaDgalactoside (Xgal). An active, tetrameric betagalactosidase hydrolyzes Xgal yielding a blue precipitate, detected as blue colonies when plated. Since insertion of pBR322 DNA will not produce a functional alphapeptide of betagalactosidase due to the disruption of the lac Z alpha gene on the multiple cloning site, we detected colorless (white) colonies in the presence of Xgal, indicating successful cloning.  ?0*  152 Name of Presenter: Jarvis Washington+t,,,ԌInstitution: Grambling State University, Classification: Senior Major Area of Study: Physics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. A. N. Murty  ?  NMR and Magnetic Character Study of CuCo Bimetallilcs Cobalt and Copper are active elements in a family of catalysts that can convert syngas to mixed alcohols. Though the activity and selectivity are known to be governed by the Co/Cu atomic ratio, the scientific basis remains unclear. Since any perturbations that occur in the dshell charge distribution due to intermetallic interactions, would influence both the catalytic as well as the magnetic properties of the transition metal, we investigated the changes in the magnetic character of a series of CuCo composites as Cu/Co ratio varies from 0.2 4.0. Our NMR and magnetization results reveal that the morphology and metallic charge distribution are sensitive to the metal ratio and that strong intermetallic interactions do occur producing significant shifts in the NMR lines of cobalt. The electronic charge density of cobalt seems to be approaching that of iron as copper content increases beyond 50%.  ?P  153 Name of Presenter: Patricia Watson Institution: Oklahoma State University Classification: Senior Major Area of Study: Physics/Mechanical Engineering NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. James P. Wicksted  BX  Normal and Resonant Raman Scattering from EU3+ Doped Alkali Silicate  ?# Glasses We report the changes observed in both the low and high frequency  C{ bands of network modified cations M2OSiO2 where M = Li, Na, K, Rb,  CG Cs. Three network modifiers (15.0 Li2O, 5.0 BaO, 5.0 ZnO and 5.0  C Eu2O3 (dopant ion) in mol %) have been added to the melt of  C amorphous SiO2. The Raman spectra of several alkalimodified silicate based glasses were measured and the results interpreted. All samples were thermally irradiated at room temperature, (T=293K) by laser excitation source of 514.5 and 457.9 nm. We will show that there is a relationship between the effective mass of low frequency Raman bands, high frequency shifting, and line widths at half maximum.  ?'  154 Name of Presenter: Karl Weckwerth Institution: University of California, Riverside Classification: Graduate Student  +u,,,ԌMajor Area of Study: Mathematics NSF Sponsored Program: RCMS Faculty Advisor: Dr. John Norbeck  ?   Global Sensitivity Analysis of Atmospheric Models An understanding and ability to predictively model the gasphase chemical transformations which occur when pollutants are emitted into the atmosphere is critical in relating emission to air quality. In particular, the chemical mechanisms are highly complex and have uncertainties which translate into uncertain assessments of air quality impacts of emissions control strategies. This project evaluated the sensitivity of a complex urban atmospheric model to uncertainties in the emissions of volatile organic compounds (VOC's) and oxides of nitrogen (NOx). The procedure used was based on the Fourier Amplitude Sensitivity Test (FAST). This technique associates each uncertain parameter of the chemical mechanism with a specific frequency in the Fourier transform space of the system. The sensitivity of each parameter to important VOC compounds is determined by solving the model for specific values of the input parameters.  ?  155 Name of Presenter: Kimberly S. Weems Institution: Spelman College Classification: Senior Major Area of Study: Mathematics NSF Sponsoring Program: RCMS Faculty Advisor or Mentor: Dr. Sylvia Bozeman  ?  Round for Eigenvalues of a Real Symmetric Positive Definite Matrix Let A be a real symmetric positive definitive matrix with  C  eigenvalues 1...n and a set of orthonormal eigenvectors  C u1,...,un. This project focuses on a method for approximating matrix eigenvalues. We find a lower bound for the largest  C eigenvalue, 1, and an upper bound for the smallest eigenvalue, n. These results can be used to determine a value for  that will  C ensure convergence of the iterative scheme, xK1=xk + (bAxk), for solving linear equations. Numerical results from experimentation with theoretical values for  will be presented.  ?$  156 Name of Presenter: Reginald B. Wilcox Institution: Pennsylvania State University Classification: Junior Major Area of Study: Chemical Engineering NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Wayne R. Curtis  ?+  The Effects of Sparging on Plant Cell Suspension Cultures +v,,,ԌThe purpose of growing plant cell suspension cultures in a bioreactor is to optimize oxygen mass transfer while operating within the shear tolerance limits of the plant cells. The oxygen is usually supplied by the sparging of air or pure oxygen through the cell suspension. To maximize the oxygen mass transfer and the uptake of the cells, the bulk liquid must be constantly mixed or stirred. This is accomplished in a bioreactor that has an impelier or an airlift system. The use of such reactors in previous experiments produced a high shearing effect on the cells and slowed down their growth rate. My research project this summer was to determine if the air bubbles produced by the spargers cause the high shearing effect on plant cell suspension cultures. The cells were grown in a small reactor on a shaker table that was constantly being sparged for a fourteen day period. The cells were then harvested to take fresh and dry weights of the cells. This experiment was run twice. Both runs of the experiment were conclusive in proving that bubbles are not harmful to plant cell suspension cultures.  ?  157 Name of Presenter: Jenae D. Williams Institution: Pennsylvania State University Classification: Senior Major Area of Study: Plant Physiology NSF Sponsored Program: RCMS Faculty Advisor or Mentor: Dr. Daniel J. Cosgrove  ?  Extension of Isolated Plant Cell Walls: Effects of Gibberellic Acid The plant growth hormone, gibberellic acid (GA), was found in previous studies to stimulate growth in plants treated with red light (a photoinhibitor) and uniconozol a (GA biosynthesis inhibitor). This study examined the effects of GA on the extension properties of isolated plant cell walls. Longterm extension of isolated hypocotyl walls were measured under tension and under acidic conditions with an extensiometer (or creep'meter). In uniconozol treated plants GA had little effect on the creep rate. This suggests that GA is not acting in this tissue by affecting wall creep properties. In contrast, GA in red light treated plants enhanced the extension (creep) rate of isolated walls thus supporting the hypothesis. One mechanism by which GA might stimulate extension within the cell wall is by increasing the production of wall enzymes that stimulate creep activity. Alternatively, wall susceptibility to these enzymes might be altered. further research must be conducted to confirm either of these hypotheses. H&w,,, INSTITUTIONAL RESEARCH AND DEVELOPMENT PROGRAMS RESEARCH IMPROVEMENT IN MINORITY INSTITUTIONS (RIMI) MINORITY RESEARCH CENTERS OF EXCELLENCE (MRCE)  x,,, RESEARCH IMPROVEMENT IN MINORITY INSTITUTIONS (RIMI)  ?  158 Name of Presenter: Olushola M. Akinniyi Institution: Southern University Classification: Graduate Student Major Area of Study: Molecular Virology NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Chaoyun T. Shih Characterization of a Viral Protease Inhibitor Isolated from Cowpea Embryo The genome of cowpea mosaic virus (CPMV) consists of two separately encapsidated RNA molecules of plusstrand polarity, middle RNA (MRNA) and bottom (BRNA). Each of these RNAs contains one long open reading frame. In the rabbit reticulocyte system, the BRNA directs the synthesis of a 200,000 dalton precursor polyprotein which is immediately cleaved into 32K and 170K polypeptides. Upon prolonged incubation of the translation mixture, the 170K polypeptide is further cleaved into 110K, 87K, 84K, 60K, 58K, 24K and 4K polypeptides. These in vitro processing reactions are catalyzed by an enzyme coded by the BRNA itself. It has been reported (Shih et al, J. Virol. 61:912915, 1987) that an inhibitor activity is present in cowpea embryo that can inhibit the primary cleavage of 200K to 32K and 170K polypeptides. Thus, in the presence of the inhibitor, the 200K polyprotein remains totally uncleaved. Basic characterization experiments were carried out in this research. The results of these studies are summarized as follows: (1) The inhibitor is undialyzable. (2) It is stable in pH range of 5 to 9. (3) It is stable at low temperature (30 C) but rapidly denatures at higher temperature. (4) The inhibitor is resistant to ribonuclease A treatment, but sensitive to trypsin treatment. 159 Name of Presenter: Kwadwo Appiah Institution: Morehouse College Classification: Junior Major Area of Study: Physics NSF Sponsored Program: RIMI Faculty Advisor: Dr. Carlos R. Handy The Eigenvalue Moment Method: Oscillations of the Volcano Function The Eigenvalue Moment Method (EMM) is a novel theory for finding converging lower and upper bounds to the discrete, low lying, spectrum of singular, multidimensional, Schrodinger Hamiltonians. The recent work of Handy, Giraud, and Bessis (Phys. Rev. A 44,+y,,, 1505, (1991)), has resulted in a dynamical system reformulation of the basic EMM approach, with special emphasis on the importance of  C an underlying convex function, FE(u) = Min%%=0,1  C$ , referred to as the volcano function. It  C is known that the maximum of this function, V(E) = Maxu FE(u), oscillates with respect to its Edependence. Based on an earlier work by Handy and Lee (J. Phys. A; Math. & Gen. 24, 1565 (1991)), it is argued that the various local maximas of V(E) are determined by the location of the excited states of the system.  ?l  160 Name of Presenter: Andrea Ashley Institution: Prairie View A&M University Classification: Senior Major Area of Study: Chemistry NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Hylton G. McWhinney  ?t  Surface Phenomena In Portland Cement Enhanced surface carbonate formation in Portland cement doped with the priority metal ions, lead and mercury, has been reported by McWhinney and coworkers. The presence of the carbonate was determined by XRay Photoelectron Spectroscopy (XPS). Deleterious effects will occur in the physical integrity of Portland cement if the increased surface carbonate exists as a bulk phenomena. High solubility of carbonate in cementitious stabilization media will render the matrix incapable of acting as good solidification/ stabilization media. The proposed investigations will determine the bulk carbonate content of cement doped with lead and mercury, compared to that of undoped cement.  ?,  161 Name of Presenter: Lyndon F. Barnwell Institution: Meharry Medical College Classification: Graduate Student Major Area of Study: Physiology NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. James G. Townsel Second Messenger Mediated Regulation of the Choline Cotransporter of Limulus Corpora Pedunculata Previous work in this laboratory has demonstrated the presence of a high affinity choline uptake system (HAChUS) in the central nervous system (CNS) of Limulus. We and other have shown that the HAChUS subserves the synthesis of releasable acetylcholine (ACh) and may be ratelimiting in the synthesis of ACh (Mulder et al., Brain Res. 70:372376, 1974). A physiologically interesting characteristic of the HAChUS is that its capacity appears coupled to nerve impulse activity (i.e. depolarization) (Simon and Kuhar,+z,,, Nature, Lond 255:162163, 1975; Barker, Life Sci. 18:725732, 1976; Ivy and Townsel, Comp. Biochem Physiol. 86C:103110, 1987). There is recent evidence that the regulation of the HAChUS may be controlled by second messengermediated phosphorylation reactions (Breer and Knippers, J. Neurobiol 21(2):269275, 1990). In this report we provide preliminary evidence which suggests that the increase in transport capacity of the Limulus HAChUS may be mediated by the CAMP second messenger system. Incubations of corpora pedunculata slices with octopamine, an alpha adrenergic agonist and adenylate cyclase activator, increased in a concentration dependent manner the level of activity of the HAChUS. Similar incubations of corpora pedunculata slices with the CAMP analog 8BrCAMP also increased the level of activity of the HAChUS in a concentration dependent manner. Additional experiments using phorbol esters, forskolin and other compounds will be conducted to further characterize the second messenger system regulation of the HAChUS.  ?  162 Name of Presenter: Michele Boone Institution: North Carolina A&T State University Classification: Graduate Major Area of Study: Biology NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Thomas Jordan The Use of Negative Stains to Study Membrane Differentiation in Caulobacter Crescentus Caulobacter crescentus undergoes a dimorphic cell cycle in which a flagellum, pili, a holdfast, and a stalk are temporally produced at the cell poles. Intracellular membranes have been observed by transmission electron microscopy (TEM). Medially located mesosomes associated with the site of cell division have been observed in negative stains or thin sections of cells. Polar membranes associated with stalk formation have been observed in thin sections but not in negative stains. We observed the presence of polar and medial membranes at various stages of the cell cycle of c. crescentus using phosphotungstic acid (PTA), uranyl acetate, or ammonium molybdate as negative stains. The mesosomes developed by tubular invagination while the polar membranes developed by tubular evagination of the cytoplasmic membrane. Both types of membranes were differentially expressed during the cell cycle. A crosswall in the stalked pole of the cell appeared to originate from the peptidoglycan of the cell wall and may be a precursor of the crossbands found in the stalks. We propose that septation may be associated with polar membrane formation during the cell cycle.  ?'  163 Name of Presenter: Frank S. Borris II Institution: University of the District of Columbia Classification: Sophomore Major Area of Study: Biomedical Engineering+{,,,ԌNSF Sponsored Program: RIMI Faculty Advisor: Dr. J. Vossoughi Residual Strain in Arteries For over a century scientists studying the function of blood vessels considered the blood vessel removed from the body as stress free configuration. Vaishnav and Vossoughi [1983] showed that an isolated arterial ring (in the absence of the axial force and the blood pressure) contains some internal stress known as Residual Stress. The strain corresponding to residual stress is called Residual Strain. The value of the intimal compressive residual strain was obtained as approximately 10%. The role of the residual stress is to reduce the stress level in the artery during its physiological function. In extending this work, we further cut an arterial ring into two rings (inner and outer rings) and performed the residual strain measurement on both rings. The results indicates that the inner ring is under even more residual strain (twice more). This is a highly intelligent safety feature incorporated in the design of the blood vessels. 164 Name of Presenter: Angel Castellanos Institution: City College of New York Classification: Graduate Student Major Area of Study: Physics NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Joseph A. Johnson III  ?  Chaotic Signatures in a Collisional Turbulent Plasma: Limit Cycles and Strange Attractors Using a glow discharge tube, fluid-like turbulent features are observed in a room temperature plasma at N(ion)=3.11(E9)cm(E-3). Ion density fluctuations (IDF) and neutral light emission fluctuations (NLEF) are monitored with Langmuir probes and neutral emissions respectively. From FFT and correlation profiles, it is found that both IDF and NLEF are turbulent. Both IDF and NLEF signals have a power-law dependence on frequency with values for the spectral index well within the regime of characteristic plasma turbulent values. The degree of turbulence is found to be sensitive to a pressure-current-temperature based control parameter or pseudo-Reynolds number R(p,I,T). Two different pressure regimes are identified for which limit cycles and strange attractors are reconstructed. It is observed that as the temperature increases, the limit cycles evolve into a topological complex attractor. 165 Name of Presenter: Leticia Y. Estrada Institution: University of Texas at El Paso Classification: Senior+|,,,ԌMajor Area of Study: Geological Sciences NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Nicholas E. Pingitore Jr.  B  Calorimetric Analysis of the System Ag2SAg2Se The results of differential scanning calorimetry (DSC) of synthetic compounds of silver, sulfur, and selenium permit the construction  CC of a partial phase diagram for the system Ag2SAg2Se. Samples were observed to undergo a rapid, reversible solidstate inversion  C at temperatures between 75 and 175 oC; the transition temperature varied systematically with composition. This behavior is consistent with the presence of two solid solutions in the system  C3 Ag2SAg2Se at room temperature, as previously documented on the basis of xray diffraction. Double or broadened DSC peaks were  C observed in the compositional range from approximately Ag2S0.4Se0.6 to  C Ag2S0.3Se0.7, indicating the presence of two solid phases in these samples. This finding signifies the occurrence of a miscibility gap in that compositional range, a deduction also made from the Xray data. Additional xray diffraction data are needed to characterize the hightemperature allotrope, probably a single solid solution.  ?  166 Name of Presenter: Andria Freemont Institution: Jackson State University Classification: Senior Major Area of Study: Chemistry NSF Sponsored Program: RIMI Faculty Advisor or Mentor: Dr. Eric A. Noe Dynamic NMR Studies of the ElectronDonating Ability of the Cyclopropane Ring Many experimental and theoretical studies have shown that conjugation occurs between a cyclopropane ring and an adjacent ! acceptor. For example, the high reactivity of cyclopropylcarbinyl halides toward solvolysis is a consequence of this effect. Thus, conjugation with the threemembered ring has qualitatively the same effect as conjugation with a double bond or phenyl group. In compounds such as cyclopropanecarbaldehdye, a twofold barrier to rotation of the aldehyde group exists, due to electron donation by a Walsh orbital of the ring to the vacant !* orbital of the carbonyl group. The minor conformation (1%) has the methine and aldehyde hydrogens eclipsed, and the major conformation (99%) has these hydrogens trans to one another. The barriers to interconversion of these conformations are smaller than for benzaldehyde, and indicate that the phenyl group is a better electron donor than the threemembered ring. Other related studies will also be described.  ?)  167 Name of Presenter: G.V. Garcia+},,,ԌInstitution: New Mexico State University Classification: Graduate Student Major Area of Study: Mechanical Engineering NSF Sponsored Program: RIMI Faculty Advisor: Dr. Larry K. Matthews Integration of ESPI and Structural Analysis to Determine the Impact of Structural Defects The identification of a defect and the ability to determine its impact on the structure provides the information needed to determine the resulting integrity of the structure. Electronic Pattern Speckle Interferometry (ESPI) is used to help find defects. One shortcoming with ESPI is its inability to determine the impact of the defect on the structural integrity. Displacement data from ESPI measurements can be used to determine the parameters of a structure, thus providing a quantifiable means of determining the structural integrity. Parameter estimation techniques provide the means to bring ESPI data and structural model together. A preliminary study of the integration of parameter estimation and ESPI displacement output on a fixedfree supported beam will be presented in this paper. The results of this experiment will then be used as a basis for analyzing more complicated systems. 168 Name of Presenter: Hector R. Gonzalez Institution: St. Mary's University Classification: Senior Major Area of Study: Electrical Engineering NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Mehran Abdolsalami Near-Threshold Electron Molecule Collision Rotational and vibrational excitations induced by electron molecule collision are studied widely. The Lab-Frame Close Coupling (LFCC) theory includes all dynamical system interactions and solves simple systems (e.g., e-H2). However, its use becomes impractical for intricate systems even on today's super computers. The Adiabatic Nuclei (AN) theory based on Born-Oppenheimer approximation - separating electrons and nuclei motions - treats initial and final target states as degenerate, violating energy conservation. Research shows that the AN method produces accurate cross sections at high energies, however, at near-threshold energies the results are not reliable. We address essential concepts of First Order Non-Degenerate Adiabatic (FONDA) theory. This technique eliminates target state degeneracy, thereby improving cross sections at near-threshold energies. Furthermore, it maximizes computational efficiency and extensibility to complex systems. We present FONDA results using separable and model exchange potential and describe the implementation of exact exchange effect in this theory. +~,,,Ԍ Ù 169 Name of Presenter: Timothy A. Hawkins Institution: Wayne State University Classification: Graduate Student Major Area of Study: Physiology NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Joseph C. Dunbar  ?  Role of Neuropeptide Y in Mechanisms of Visceroendocrine Control and Nutrient Homeostasis Mediated by the Nucleus Tractus Solitarius Neuropeptide Y (NPY) is a potent bioactive peptide distributed in specific CNS regions. In particular, NPY receptors are found in high concentrations in the nucleus tractus solitarius (NTS), a principal region of the brainstem for integrating visceral sensation from hepatic, gut and pancreatic receptors with nutrientrelated signals conveyed in the CSF and blood via its subadjacent location with the area postrema, a circumventricular organ. The subpostremal NTS also exhibits very high densities of insulin receptors. NPYmediated pathways have been implicated in the regulation of a number of viscerobehavioral responses such as eating behavior, gastrointestinal responses and regulation of metabolic activity. Microinjections of NPY were made into the subpostremal NTS and blood samples were subsequently collected from the femoral vein. NPY microinjection resulted in a significant increase in insulin secretion within 5 minutes that returned to baseline at 30 minutes. However, microinjections of NPY did not significantly alter the plasma glucose in this model system. These results suggest that NPY can act directly on the NTS to increase circulating insulin levels and that the NTS may be a major brainstem site that directly mediates the central action of NPY on nutrient homeostasis.  ?   170  ?  Name of Presenter: Calandra Hopkins Institution: Clark Atlanta University Classification: Junior Major Area of Study: Chemistry NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Eric A. Mintz Synthesis of AmimoSubstituted Cyclopentadienyl Ligands; Application to Organometallic Chemistry  C% Addition of LiNHR and LiNR2 to fulvenes gave the corresponding amine  CL& substituted cyclopentadienly ligands [C5H4CH(R)NHR]é ( I ) and [C5H4CH(R C' )NHR]é( II ). Treatment of I with BuLi followed by a second equivalent  C' of fulvene gave the corresponding bridged ligand, [C5H4CH(R)NRCH(R) C( C5H4]2III. Treatment of these ligands with metal halides leads to new organometallic complexes. The preparation of these ligands and complexes will be described.  +,,,Ԍ ? ԙ 171 Name of Presenter: Jeffery F. King Institution: FAMU/FSU Classification: Graduate Student Major Area of Study: Mechanical Engineering NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. N. Chandra  ?  Mechanical Characterization of Composites Materials Future aerospace and military systems require the use of materials with high specific strength and modulus capable of operating at elevated temperatures for extended periods of time. Advanced polymeric, metallic, and ceramic matrix composites are the solution to such needs. These engineered materials allow designers to efficiently build a structure to meet the specific needs, based on the principles of micro and macromechanics. With micromechanics we can analytically predict the properties of a composite lamina from the basic properties of its constituent materials using a simple ruleofmixtures approach. The ruleofmixtures approach effectively assess the efficiency of load transfer in the constituent materials. This method serves as an adequate material design tool with certain assumptions and limitations. To verify the micromechanics it is important that we empirically determine the properties of the composite through simple mechanical tests on a composite lamina. These test view the lamina properties from a macromechanical standpoint wherein the material is presumed homogeneous and the effects of the constituent materials are detected only as average apparent properties of the composite. This macromechanical characterization predicts the overall lamina behavior and serves primarily as a structural design tool. In this paper a link between micromechanics (material design) and macromechanics (structural design) is made through novel experimental methods. Explicit procedures to predict the material properties quantitatively and qualitatively are described. In addition a comprehensive methodology to completely characterize a transversely isotropic material is presented.  ?!  172 Name of Presenter: Dixie J. Matlock Institution: University of Texas at El Paso Classification: Graduate Student Major Area of Study: Metallurgical and Materials Engineering NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. L.E. Murr Effects of Strain State and Low Temperature on Deformation Strain ?h) Induced Corrosion (Sensitization) in 304 Stainless Steel We have observed that sensitization and carbide precipitation in 304 SS is deformation (strain) dependent. Like straininduced+,,, martensite nucleation, carbide nucleation in 304 SS occurs preferentially at shearband intersections which increase with strain and strain states. Consequently, we have demonstrated that sensitization, measured by EPRDOS, also differs for uniaxial straining to 33% (40% true) strain as compared to multiaxial (rolling) straining. Uniaxial straining at liquid nitrogen temperature was shown to produce a dramatic reversal in the ordinary sensitization behavior where grain boundary etching occurs first with aging, followed by matrix etching. In the lowtemperature deformation experiment, no grain boundary sensitization was observed initially while the matrix exhibited characteristic test attack. An exploration for these deformationrelated sensitization behaviors requires detailed and selected examination of microstructure evolution utilizing transmission electron microscopy. This paper illustrates these new observations and the powerful role that electron microscopy plays in the understanding fundamental materials issues. H ,,, 173 Name of Presenter: Carlee McClellan Institution: Northern Arizona University Classification: Sophomore Major Area of Study: Chemistry NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Michael P. Eastman The Photochemical and Redox Properties of a New Class of Water  ? Soluble Organic Free Radicalsthe Carbvoxyverdazyls The advent of magnetic resonance imaging (MRI) has created a need for water soluble paramagnetic materials as contrast agents. While complexes of metal ions such as Gd(III) are most commonly used for this purpose, water soluble, S=1/2 radicals such as the nitroxides have potential for special MRI applications. Recently, we have synthesized a new class of water soluble organic radicals, the carboxyverdazylys. Here the results of cyclic voltammetry experiments on carboxyverdazyls in aqueous and nonaqueous solvents are reported along with the results of photochemical decomposition and electron spin resonance (ESR) experiments. Complexation of carboxyverdazyls by both gamma and beta cyclodextrin is established by optical spectroscopy and ESR. Surprisingly these complexes are less photochemically stable than the uncomplexed carboxyverdazyls. Evidence is presented to indicate that water soluble verdazyls interact with DNA.  ?  174 Name of Presenter: Reinaldo G. Nieves Institution: New Mexico State University Classification: Graduate Student Major Area of Study: Analytical Chemistry NSF Sponsored Program: RIMI Faculty Advisor: Dr. Gary A. Eiceman and Dr. Fernando Cadena  ?  Adsorption Properties of Alkylammonium Montmorillonites for Aqueous Solutions of Organic Compound in Liquid Chromatography Montmorillonite can be immobilized in a silica polymer to yield a material that exhibits adsorptive properties of clays and flow properties of silica for liquid chromatography. Flow of 0.5 to 2.5 ml/min were attained at pressures of 1001000 psi for 150200 mesh packings using aqueous solutions at 2060$C. Montmorillonites were modified by exchange of the inorganic interlayer cations with alkyl  C$ ammonium ions tetramethyl ammonium (TMA+), tetraethyl ammonium  C% (TEA+), tetrapropyl ammonium (TPA+), tetrabutyl ammonium (TBA+),  CP& hexadecyltrimethyl ammonium (HDTMA+), and ethylhexadecyldimethl  C' ammonium (EHDMA+). Adsorption studies for alkyl and halogenated benzenes suggest a retention mechanism dominated by steric  C( considerations in the smallest cation (TMA+) gradually changing to a mechanism controlled by partition interactions as the size and hydrophobicity of the interlayer alkyl ammonium cation increases.  +,,,Ԍ ?  Ù175 Name of Presenter: Charles Nelson Institution: Morehouse College Classification: Senior Major Area of Study: Biology NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Betty R. Jones Schistosomiasis: Cholinesterase Activity in Biomphalaria Glabrata The snail intermediate host of Schistosoma mansoni is considered the weakest link in the life cycle of the parasite. The role(s) of cholinesterase in susceptible and nonsusceptible snail hosts is/are poorly understood. The objective of this study is to identify and localize specific acetylcholinesterase (AChE) and nonspecific butyrylcholinesterase activity (BuChE) in Biomphalaria glabrata utilizing cryomicrotomy and spectrophotometry methods and techniques. Frozen cryostat sections showed the presence of AChE activity primarily in the cytoplasm of ganglion cells and the neurofibrils of the central ganglion ring. Kinetic studies showed a twofold increase in AChE activity in infected snails in comparison to noninfected snails. In unshelled infected snails,  C the mean value for AChE was 0.068  0.20moles miné1 mg proteiné1,  C compared to 0.044  0.017moles miné1mg proteiné1 for uninfected snails (p<0.5). Measurements of BuChE activity in noninfected snail group revealed a twofold increase of enzyme activity compared to infected snail group. Further studies are underway to determine the precise subcellular localization of Cholinesterase B. glabrata. (Supported by NSFRIMI and by NIHMBRS Grant S06GM4591301, Morris Brown College) 176 Name of Presenter: SaJean H. Page Institution: Tuskegee University Classification: Junior Major Area of Study: Mechanical Engineering NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. T. Habtemariam Multimedia-Based Scientific Visualization  ?!  Multimedia-based visualization is rapidly becoming a crucial element in this age of information technology. The advent of this visualization technique brought several opportunities for insight and understanding in scientific fields. Multimedia visualization combines audio digitization with static and dynamic imagery in a non-linear form that is conducive to comprehension. In this presentation the use of interactive analog imagery and digital videography in the development of resources that enhance the learning and understanding process will be emphasized. Numerous analog to digital conversions are performed to allow the importation of sounds and images. These sounds and images are+,,, collected into a multimedia database where they are re-organized into the logical order of presentation for the desired subject matter. Using the appropriate computer hardware and software, one manipulates geometry, color and motion as well as sound to create a more vivid and deeper appreciation of the scientific reality that is being modeled.  ?  177 Name of Presenter: Michael Parizon Institution: Wayne State University Classification: Graduate Student Major Area of Study: Physiology NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Robin A. Barraco Role of Neuropeptide Y in Mechanisms of Cardiorespiratory Control Mediated by the Nucleus Tractus Solitarius Neuropeptide Y (NPY) has been shown to be localized in a number of CNS regions with very high densities of NPY receptors exhibited in the nucleus tractus solitarius (NTS), a major integrating site in the dorsal medulla for coordinating visceroendocrine response patterns. In this study, microinjections of NPY were made into the subpostremal NTS of three separate group of rats: intact, decerebrate and glossopharyngeovagotomized. NPY (10100 pmol/rat) microinjections elicited doserelated depressor responses and reductions in respiratory minute volume in intact rats. Decerebration did not affect the NPYinduced cardiorespiratory patterns significantly whereas glossopharyngeovagotomy (GV) enhanced the hypotension and reductions in respiratory rate. On the other hand, GV abolished the NPYevoked bradycardia and reductions in tidal volume. Cardiorespiratory responses elicited by NPY were mimicked  C  by NPY1336, a fragment of NPY exhibiting selective agonist actions  C at presynaptic Y2 receptors, whereas [Leu31, Pro34]NPY, a selective  C agonist at postsynaptic Y1 receptors, was ineffective. These results suggest that NPY modulates primary visceral afferent  CL information via actions at presynaptic Y2 receptors distributed on IX and X cranial nerve terminals projecting to the subpostremal NTS. The influence of hypothalamic connections with the NTS on these specific response patterns appeared not to be substantial. Thus, NPY likely plays a crucial role in the modulation of NTSmediated cardiorespiratory response patterns.  ?$  178 Name of Presenter: John G. Ramirez Institution: University of Puerto Rico Classification: Graduate Student Major Area of Study: Mathematics NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Oscar Moreno +,,,ԌGenerating Costas Sequences in a Parallel Computer Costas sequences are special permutations which are useful in sonar and radar applications. In this work our main result is a parallel algorithm that computes c(n), the number of Costas sequences of size n, in a very efficient manner. We computed c(19) in one week (this case would had taken Dr. J. Silverman, a previous researcher from the ARMY Research Office more than one year) and C(20) in one month (both in Dr. Silverman's program and in our's, the computation time of c(n) is five times longer than that for c(n1)). The time quoted here is for our original implementation of the algorithm in the OCCAM language, which was run in a transputer based system (with eight Inmos T800 processors). We have also implemented it in then MPL language for the MasPar Data Parallel Machine. Presently we are porting it to the SISAL language in order to run it in Cray machine, and we are achieving very good run times. 179 Name of Presenter: Nathan L. Richardson Institution: State University of New York/Morgan State University Classification: Graduate Student Major Area of Study: Electrical Engineering NSF Sponsoring Program: ENG/RIMI Faculty Advisor or Mentor: Dr. Carl White and Dr. Linda Head A Large-signal Equivalent Circuit Model for a Novel AlGaAs/InGaAs/GaAs Pseudomorphic High Electron Mobility Transistor Due to the increasing sophistication in device processing technology, many new devices are being developed for extremely high frequency applications. With the development of these new devices comes a need for developing models that will accurately predict the performance of the device over its full operating region. Accurate models can then be implemented in computer-aided design packages, thus reducing the cost of circuit production. This is especially true for integrated circuit technology. It is thus of interest to develop models for devices as soon as they come off of the design board and enter into the engineering mainstream. In this investigation, a novel device will be modeled for both small- and large-signal applications. Existing models will be used to determine whether these models can be improved upon or if new models must be developed altogether.  ?#  180 Name of Presenter: Timothy Robinson Institution: Morgan State University Classification: Graduate Student Major Area of Study: Neural Networks NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. GeeIn Goo Phoneme Detection and Classification As Inputs For Neural Network Speech Recognition +,,,Ԍ ?  ęThrough the use of signal processing techniques for, such as discrete FFTs with an overlapping, sliding window, an audio signal can be transformed into its time and spectral components. When the above transforms are applied on a sampled audio signal, a three dimensional picture of time, frequency, and amplitude can be generated. Detection of consonants and vowel transitions are possible when viewing this data as a three dimensional plot; by using phonemes, which are words or phrases that have similar sounds, characteristics of the spoken word were evident. By classifying these patterns and transitions, the data can be input to a simple neural network for speech pattern recognition.  ?(  181 Name of Presenter: Ivonne Santiago Institution: New Mexico State University Classification: Graduate Student Major Area of Study: Environmental Engineering NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Fernando Cadena Removal of Hexavalent Chromium from Water Using Tailored Zeolites  C Removal of Cr+6 is of major concern due to its carcinogenic properties and other deleterious effects to human health. Uses of  CT Cr+6 include, among others, corrosion control and preparation of catalysts in the oil and gas industries, and stainless metal and chromium plate in the iron and steel industries. Adsorption studies were conducted to determine the selectivity of  C@ natural and tailored zeolites for Cr+6. Three types of zeolite deposits were tested that contained approximately 60%, 40% and 20%  C of clinoptilolite, respectively. No significant removal of Cr+6 occurred when the zeolites were used in their natural form.  Ch However, adsorption of Cr+6 onto zeolites was significantly enhanced by replacing naturally occurring inorganic cations by quaternary ammonium ions. By selecting the appropriate tailoring agent and quantity, removal  CT of Cr+6 can be accomplished in its anionic forms, as CrO4é2 or HCrO4é1.  C Removal of Cr+6 in its anionic forms may result from charge reversal at the surface of the zeolite, suggesting that anion exchange is the responsible mechanism for removal. This study showed that the clinoptilolite content, the External Cation Exchange Capacity (ECEC) of the zeolite deposit, and the molecular structure of the organic cation affect the capacity to  C% remove Cr+6.  ?'  182 Name of Presenter: Keithia Simpson Institution: Clark Atlanta University Classification: Senior+,,,ԌMajor Area of Study: Mechanical Engineering NSF Sponsored Program: RIMI Faculty Advisor: Dr. Olugbemiga A. Olatidoye A VisualOriented Intelligent Graphic User Interface for Physicists The focus of this paper is on the development of a GraphicUserInterface (GUI) for physicists. Presently, most of the available GUIs support geometric entity drawing, but they are not flexible enough to support experimental processes. The research involves how physicists execute their problem solving skills, in the laboratory environment. The anticipated result of this investigation will be a new GUI that will assist physicists in their problem solving and experimental scenarios, as well as simplify their instructional and tutorial tasks. The initial part of the development will entail a link between a 3D modeling design package and an object oriented programming language, C++. A simple physical system will be visually represented in the 3D package, and it's parameters will be controlled by C++ in the Windows environment.  ?0  183 Name of Presenter: Angela S. Tate Institution: Hampton University Classification: Graduate Student Major Area of Study: Marine Science NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Robert A. Jordan Larval Fish Prey Organisms on Georges Bank, June 1992 Fine mesh (0.053 mm) zooplankton samples collected on three transects across Georges Bank during the June 1992 cruise conducted by the National Marine Fisheries Service on the NOAA research vessel Albatross IV were dominated by a calanoid copepod, Pseudocalanus and by cyclopoid copepod, Oithona. On one transect, for which sample processing has been completed at Hampton University, the population density of total copepod nauplii and copepodids ranged from 3.3 to 4.1 million per 100 cubic meters. Pseudocalanus individuals accounted for 29 to 34 % of the total copepods, and 76 to 83 % of Pseudocalanus were within the size range of 0.1 to 0.2 mm cephalothorax width preferred as prey by cod and haddock larvae. Data from accompanying coarse mesh (0.333 mm) samples being processed a NMFS laboratories will be used in conjunction with the fine mesh data to test for correlations between abundances of larval fish and their prey and between coarse and fine mesh estimates of copepod densities.  ?'  184 Name of Presenter: Zachary Wheeler Institution: Howard University Classification: Graduate Student Major Area of Study: Applied Mathematics+,,,ԌNSF Sponsored Program: RIMI Faculty Advisor or Mentor: Dr. James A. Donaldson A BoundaryValue Problem with a Small Parameter Of concern here is an elliptic boundaryvalue problem with a small parameter e > 0 that describes the flow of water in a region with a horizontal bottom and that is related to the linear "shallow water theory." In this paper we give a rigorous derivation of the "shallow water theory'." In our analysis it is shown that the restriction of the solution of a boundaryvalue problem for an elliptic partial differential equation to a portion of its boundary is approximated by the solution of an initialvalue problem for a hyperbolic partial differential equation. These results provide a  C partial extension to 3 of general result in 2 obtained by James A. Donaldson and Daniel A. Williams in The Linear Shallow Water Theory: A Mathematical Justification. 185 Name of Presenter: Anthony B. Will Institution: Wayne State University Classification: Graduate Student Major Area of Study: Electrical Engineering NSF Sponsoring Program: RIMI Faculty Advisor or Mentor: Dr. Andrezej W. Olbrot Can All Unstable Natural Processes be Stabilized Mathematical control theory answers in a positive way the above question by stating that any process, whose model has so called controllability and observability properties, can be shifted by a suitable choice of feedback controller. However, this is related to an idealistic situation which assumes that the real process behaves exactly according to known mathematical equations. While this happens in some isolated situations (e.g., the motion of a space vehicle under gravitational forces can be very precisely predicted on the basis of Newton laws) this is not so in most engineering processes where there are always differences between the mathematical models we use and reality. Those differences can be described by introducing uncertain parameters in mathematical models. We will demonstrate that the well established claims of control theory about stabilization should be revised if uncertain parameters are present. Specifically, there are processes which can not be stabilized in a robust way that is independent of the values of the uncertain parameters.  ?'  186 Name of Presenter: Gayla Wilson Institution: Clark Atlanta University Classification: Graduate Student Major Area of Study: Organic Chemistry*,,,ԌNSF Sponsoring Program:Program: RIMI Faculty Advisor or Mentor: Dr. Eric A. Mintz  ?X  Synthesis of Tri and Tetrasubstituted Fulvenes  ? 2,3Dimethylcyclopent2enone ( I ) and 3,4Dimethylcyclopentenone  ? ( II ) serve as useful starting materials for the preparation of tri  ?x and tetrasubstituted fulvenes. Thus, reduction of I or II with  C@ LiAlH4 followed by acid catalyzed dehydration gives 1,2dimethylcyclopenatdiene, which upon treatment with acetone and pyrrolidine in  ? MeOH gave 2,3,6,6tetramethylfulvene. Treatment of I or II with vinyl Girard reagents gives the corresponding substituted fulvenes. This synthetic work and it's application to organometallic synthesis will be described.  ,,, MINORITY RESEARCH CENTERS OF EXCELLENCE (MRCE) 187 Name of Presenter: Carlos Adorno Institution: University of Puerto Rico, Rio Piedras Classification: Senior Major Area of Study: Terrestrial Ecology NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Ned Fetcher Effects on Productivity of Climate Variation and Genome in Tropical Forest Plants A transplant experiment, where reciprocal transplants of clones and seedlings of key forest species were used to detect genetic and environmentally determined differences in productivity along an elevational gradient in a tropical moist forest. Two sites were used, one in a cloud forest and one in a lower mountain rain forest, in the Luquillo Experimental Forest of Puerto Rico. Partial results on Clibadium erosum suggest that the high elevation population was less plastic than the low elevation population, in that they experienced a small decrease in response to the environmental gradient. Sets of morphological and photosynthetic data are presented. At present, little evidence of wind (barrier treatment) effect exists on the traits measured in the three species examined. Prior experiments in non tropical regions have demonstrated existence of ecotypes in Clibadium and Psychotria, differences are not conclusive so far.  ?  188 Name of Presenter: Kenneth A. Brown Institution: Clark Atlanta University Classification: Senior Major Area of Study: Graduate Applied Physics NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Gary Swift Radiation Effects on a Floating Gate Isolation Transistors in  ? Gate Arrays The purpose of this project is to determine the effect of a floating isolation transistor on the performance of gate arrays before and after radiation. Proton tests were performed which induced a positive charge on the gate of a floatinggate nMOSFET. The results were compared to SPICE simulations and to the Cassini radiation environment. It was concluded that the effect would be small if the overlayer oxides retain the charge; however, since the charge anneals the hazard is not significant for the Cassini environment and the nMOSFET tested.  ?*  189 +,,,ԌName of Presenter: Mari Carmen Brun Institution: University of Texas at El Paso Classification: Sophomore Major Area of Study: Chemistry NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Keith Pannell  Bx Oligosilyl Derivatives of the Transition Metals (nC5ĩC5)Fe(CO)2(SiM BC e2Ĭ)nSiMe3, n = 2, 3. Their  ? Use as Catalysts for Oligosilane Reformation. Polysilanes have developed into materials with considerable potential in the areas of photoresists, photoconductors and preceramics. The bulk of the studies that have been performed in  C this arena have involved the use of linear systems R(SiR2)nR, R = alkyl, aryl. However, a few studies have shown that when the silane chain contains silyl substituents significant changes in properties are observed. The synthesis of branched oligosilanes is not well developed, and indeed somewhat complicated. In our laboratories we have shown that photochemical treatment of  Cr FeSiMe2SiMe2SiMe2SiMe3, a linear system, results in quantitative  C> reformation to FeSi(SiMe3)3, a highly branched system. We will report on the ability of this system to be used catalytically for the transformation of linear silanes to branched systems. We will also report on the effect of placing a germanium atom into the Si chain to make oligosilylgermyl materials.  ?  190 Name of Presenter: William Bryant Institution: Alabama A&M University Classification: Graduate Student Major Area of Study: Physics NSF Sponsored Program: MRCE Faculty Advisor: Dr. Putcha Venkateswarlu  ?  Study of Nonlinear Optical Properties of Guest Host Organic  ? Materials by Different Methods We present the theoretical and experimental considerations necessary to determine the second and third order nonlinear optical properties of polyvinyl prrolidine (PVP) in spin coated thin film media. The nonlinear optical properties of PVP has been directly studied by measurement of surface enhanced second and third harmonic generation. The enhancement of second and third harmonic generation was studied by doping PVP with laser dyes.  ?'  191 Name of Presenter: Agnes Carpenter Institution: City College of New York Classification: Graduate Student +,,,ԌMajor Area of Study: Electrical Engineering NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Robert R. Alfano Fluorescence Decay in Pepper Plants under Different Environments Timeresolved spectroscopy was introduced to study the fluorescence decay of pepper plants under the following conditions: (a) darkness, (b) water deprivation, and (c) leaf damage. The green leaves and the stems of the plant were excited by 100 fs laser pulses at 620 nm. The fluorescence spectrum from approximately 734 nm to 738 nm was observed. The time dynamics of the fluorescence were measured with a synchroscan streak camera. A sharp rise time and two exponential decays were observed. A noticeably increase in fluorescence intensity occurred shortly after watering.  ?H  192 Name of Presenter: Monica M. de Lugo Institution: University of Texas at El Paso Classification: Graduate Student Major Area of Study: Material Science NSF Sponsoring Program: MRCE Faculty Advisors or Mentors: Drs. S. K. Varma & Arturo Bronson The Effect of Grain Diameter and Chemical Composition on the Transient Current Response in FeCrNi Alloys The corrosive wear behavior of four alloys from the FeCrNi system has been studied. The transient current response has been measured as a function of grain diameter and alloy composition in two austenitic alloys, Fe25%Cr25%Ni and Fe13.4%Cr22%Ni, and two martensitic alloys Fe15.5%Cr10.7%Ni and Fe7.5% Cr18%Ni (all compositions are in weight percents), by a scribing technique. The effect of grain size on the current values is such that at a given load, the medium grain size shows the highest value for current, followed by the smallest grain size and the largest grain sizes. For alloys of 280 %m grain diameter, the twophase martensitic alloys yield lower transient current response than the single phase austenic alloys. It appears that the controlling mechanism for the activation or depassivation in twophase alloys is the breaking down of the crystallites of austenite and martensite during scribing, while the higher amounts of twins in the microstructure of the austenitic alloys, result in higher current values.  ?H&  193 Name of Presenter: Shelley Deosaran Institution: City College of New York Classification: Graduate Student Major Area of Study: Physical Chemistry NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Derek Lindsay +,,,Ԍ ?  ÙDesign of a Time Flight Instrument for Metal Cluster Research Metal clusters are the links joining the properties of individual atoms to those of the bulk metal. Information about the geometry, electronic and vibrational structure and dissociation energies will enable us to understand how the properties of metals change during the transition from individual atoms to bulk metal. This is fundamental to the development of better catalysts, magnetic and optical films and disks, microchips and superconductors. The instrument we are currently building consists of two stages. Stage I incorporates a pulsed laser evaporation source with supersonic expansion to produce medium sized clusters. A Wiley McClaren linear timeofflight (TOF) mass spectrometer and a mass gate are used to mass select the generated clusters. Stage II involves a dye laser, a reflectron TOF mass spectrometer and a microchannel plate detector. Our primary aim is to study these clusters using the techniques of Coherent AntiStokes Raman Spectroscopy (CARS) and Photofragmentation Spectroscopy.  ?  194 Name of Presenter: Andrew G. Edwards Institution: City College of New York Classification: Graduate Student Major Area of Study: Electrical Engineering NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Robert R. Alfano Optical Pulse Compression in a LinearCavity DyeLaser Nonlinear optical research methods such as fourwave mixing and the Zscan technique are used to study optical materials. These ultrafast optical spectroscopic techniques are often limited by the resolution of the pump and probe optical pulses used to excite the material under study. To obtain higher resolution with these spectroscopic techniques, ultrashort optical pulses need to be generated. To date, the shortest optical pulses have been obtained with the collidingpulse modelocked ringcavity dyelasers. This paper describes the design of an intracavity optical pulse compressor for a linearcavity dyelaser operating at the 620 nm wavelength. Originally, the synchronously pumped dye laser produced 0.5 psec pulses with a 350 to 400 mw average output power. It is anticipated that pulses shorter than 100 fsec will be obtained with this modified linearcavity design. This modified design is based on the approach attempted by Nakazawa et.al. Unlike Nakazawa, the author proposes using two pairs of ARcoated SF18 prisms which will require a 6.6 cm prism spacing. In addition, the author will use Kiton Red 620 and Malachite Green as the gain medium and the saturable absorber, respectively.  ?*  195 +,,,ԌName of Presenter: J.R. Galarza Institution: University of Puerto Rico, Mayaguez Campus Classification: Doctoral candidate Major Area of Study: Marine Sciences NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Thomas R. Tosteson Effect of Barracuda Ciguatoxins on Pigment Granule Aggregation on Teleost Melanophores Melanophores in the isolated scales of Stegastes planifrons (Damsel fish) were exposed to HPLC purified barracuda (Sphyraena barracuda) ciguatoxins. Scales were removed from S. planifrons with tweezers and subsequently incubated for 25 to 80 minutes in the presence of barracuda ciguatoxins. The barracuda ciguatoxins caused melano C phore pigment granules to aggregate at concentrations of 10é6 to 10ê C 9gm/ml. Brevetoxin (PbTx3) caused aggregation of melanophore  CP pigment granules in isolated scales at concentrations of 10é5gm/ml (12um). Treatment of isolated scales with adrenalin (%m), the neurotransmitter that normally activates the enervated teleost melanophores also aggregated the melanophore pigment granules. The aggregatory action of adrenalin, PbTx3 and the barracuda ciguatoxins were inhibited in the presence of dibenamine (%m), an alpha  C adrenalin sit blocker, and the Ca++ channel blocker verapamil. (10ê C 4m). These results indicate that: (1) the barracuda ciguatoxins had a component that affected teleost coloration and, (2) that the site of action of this component of the barracuda ciguatoxins and PbTx3 was on the presynaptic nerve terminals enervating the teleost scale melanophores and not directly on the melanophores themselves.  ?L  196 Name of Presenter: Manuel Garbalena Institution: University of Texas at El Paso Classification: Graduate Student Major Area of Study: Chemistry NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. William Herndon Optimum GraphTheoretical Models for Enthalpic Properties of Alkanes Simple additive schemes based on graphtheoretical properties of molecular graphs are evaluated for correlating thermodynamic properties of alkanes. The properties considered in this work are heats of formation (gas and liquid phase), heats of vaporization, and heat capacities. The original sources for thermochemical data were checked since some of the past attempts to correlate alkane  C$' properties, e.g., H?(g) have made use of calculated or interpolated values rather than restricting the analysis to experimental data. The evaluation is conducted using stepwise multilinear regression methodology. The statistical qualities of the final correlative equations are excellent (in all cases but one, squared multiple correlation coefficients > 0.995). In each case, the most+,,, successful model equation uses a labeled path of length zero, one and two as the independent variables. Therefore, each parameter has a simple molecular structure interpretation and can be obtained from the molecular graph by inspection.  ?  197 Name of Presenter: Ismael E. Gonzalez Institution: University of Puerto Rico Mayaguez Classification: Senior Major Area of Study: Remote Sensing NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Ramon Vasquez Remote Data Acquisition Unit Design The Remote Data Acquisition Unit (ReDAU) is a stand alone microcontrolledbased unit used to continuously monitor weather conditions. Parameters such as rainfall, stream flood stage, temperature, wind speed, and other factors can be monitored. The unit can determine critical conditions in the monitored parameters and it sends the information to a Network Control Center (NCC) via a radio channel. Units are located at different points, and besides collecting data, they also serve as relay stations to communicate with the farthest units and the NCC. The systems powered by an array of solar cells and batteries. Because of this, the power consumption and the amount of hardware used become critical design parameters. When the NCC determines a threatening or abnormal situation, it can instruct the unit to take local action depending on the conditions. The unit can also operate if it loses contact with NCC (isolation condition).  ?  198 Name of Presenter: Alicia Johnson Institution: Hampton University Classification: Senior Major Area of Study: Applied Physics NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Khin M. Maung Relativistic Schrodinger Equation in Momentum Space and Pseudoscalar Meson Form Factors In the constituent quark model, mesons are taken to be bound states of a quark and an antiquark. For heavy quark systems such as cc system, the use of a Coulomb like potential in a nonrelativistic Schrodinger equation is sufficient. For light mesons relativistic effects must be taken into account. In this preliminary study we solve a relativistic Schrodinger equation in momentum space. The singularities arising from the momentum space Coulomb and Linear potential are treated by employing the subtraction method developed in reference 1. The solution method together with the wavefunctions and form factors calculated will be presented. +,,,Ԍ ? ԙ 199 Name of Presenter: Isaac Jones Institution: Alabama A&M University Classification: Graduate Student Major Area of Study: Materials Science/Nonlinear Optics NSF Sponsored Program: MRCE Faculty Advisor: Dr. M. D. Aggarwal Czochralski Growth of Pure and Fedoped Bismuth Silicon Oxide Crystal Bismuth silicon oxide has been receiving growing attention as a photorefractive material and has great potential in optical data processing. In the present work, we have established a Czochralski crystal growth system including rotation and pulling mechanism with automatic diameter control and 50 kW induction heating power  CH supply. Single crystals of bismuth silicon oxide (Bi12Sio20) have been successfully growth from melts of stoichiometric composition in a platinum crucible heated by induction furnace using a pulling  C rate of 23 mm/h and a rotation speed of 10 rpm. Bi203 and Si02 of high purity were used as the starting materials. We have also grown Fe doped Bismuth silicon oxide (BSO) crystals using 0.1%Fe, 0.05%Fe and 0.1%Fe. The grown crystals are then cut,l ground and optical polished. Growth and decay of the photorefractive grating on these crystals have been studied in the laser laboratories and the result will be presented.  ?  200 Name of Presenter: Jaime Joshua Institution: Morehouse College Classification: Junior Major Area of Study: Physics NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Carlos R. Handy The Eigenvalue Moment Method: Application to Important One Dimensional Systems We investigate the application of the Eigenvalue Moment Method (EMM) to various important one dimensional Schrodinger problems. Of particular interest are radial potentials including the effects of the centrifugal angular momentum barrier term. Until now, these kinds of problems have not been analyzed through the EMM theory. Also, we investigate the effective, one dimensional Coulomb potential, V(x) = Z/|x|, so as to better understand the two dimensional quadratic Zeeman effect, for super strong magnetic fields, previously studied by Handy et al (Phys. Rev. Lett. 60, 253 (1988)).  ?p)  201 Name of Presenter: Jonathan H. Lewis+,,,ԌInstitution: Howard University Classification: Graduate Student Major Area of Study: Electrical Engineering NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Michael G. Spencer  B Growth and Characterization of (InAs)2/(GaAs)m Short Period Strain Layer Superlattice We present the results of the growth and characterization of  C (InAs)2/(GAs)m short period strain layer superlattice (SPSLSL) grown by MBE on GaAs substrates grown at 420$C and 480$C. The transport  Cg properties and photoluminescense (PL) spectrum of (InAs)2/(GaAs)m grown under varying conditions are reported. Growth conditions were optimized by monitoring the Reflection High Energy Electron Diffraction (RHEED) pattern. To measure mobility the superlattice was placed in a HEMT structure. The mobility and carrier concentration were measured at both room temperature and liquid nitrogen temperature using the Van der Pauw technique. PL and TEM studies performed on several of these samples will be discussed. It was found that deviations in the growth conditions drastically affects the quality of the material as determined from Hall and PL data.  C; Measured room temperature mobilities varied from 500 to 7000 cm2/Vsec under varying growth conditions.  ?_  202 Name of Presenter: Kojo Linder Institution: Clark Atlanta University Classification: Junior Major Area of Study: Physics NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Louis Osbourne Studies of Neutron Detection Systems for the Superconducting Supercollider The detection of muons is an important endeavor at the Superconducting Supercollider (SSC). The limited streamer drift tube (LSDT) system may be used in the SSC to detect muons because of its large pulses and limited noise interference. A calorimeter will also be used to detect and measure hadronic particle energies. We measured the sensitivity of the LSDT to neutrons with a Cf neutron source. A simulated spectrum of neutrons was obtained from 40 cm radius sphere of BPoly with a Cf source. We compared this to a spectrum expected by the colorimeter used in the SSC. Both spectra appeared to be similar even though the sources were different. We concluded that our Cf test was a good measure of backgrounds expected at the SSC. Cathode tubes were also compared. We observed that carbon coated aluminum provided excellent coating; the reason is unknown. Results will be presented and discussed.  ??*  203 +,,,ԌName of Presenter: Kimberly Looney Institution: Meharry Medical College Classification: Freshman Major Area of Study: Neurophysiology NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Hubert K. Rucker Auditory Brainstem Response and Cortical Evoked Potential Screening for Central Cholinergic Effects Central neural degeneration has been observed in Alzheimer's disease patients. Since these neurons employ acetylcholine (ACh) as their neurotransmitter, it is suggested that the symptom of this dementia are partially caused by a dysfunction in the cholinergic activity of the central nervous system (CNS). This project tested a model to assay pilot compounds for potential therapeutic benefits. The auditory system served as the basis of this model. Pyridino [1,2]imidazo[5,4 ]indolE (IMID), an experimental drug, induced cholinergic effects in the CNS similar to those produced by ACh. It was hypothesized the IMID would cross the bloodbrain barrier and influence activity in the auditory cortex and the auditory brainstem. In male albino rats, a multiunit recordercomputer interface monitored surface activity in the auditory cortex and displayed this data as histograms. Oscilloscope tracings of neural activity in the brainstem were also made. IMID decreased the latency period before neural response and increased the effectiveness of the response once it was activated. The ABR tracings indicated an increase in the variability of the response. This study suggests that the auditory system serves as a sensitive model for cholinergic activity and that IMID is capable of inducing cholinergic effects in the CNS, lending itself as a possible therapeutic agent for information processing in the CNS.  ?   204 Name of Presenter: Angela McCauley Institution: Hampton University Classification: Senior Major Area of Study: Engineering NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Oliver K. Baker Performance Evaluation of the High Momentum Spectrometer Drift  ?# Chamber A prototype of the High Momentum Spectrometer (HMS) drift chambers to be used at the Continuous Electron Beam Accelerator Facility (CEBAF) has been constructed and its performance tested. The prototype chamber has six planes (XYUVXY) with the UV stereo wires inclined at 30$ with respect to the X and X plane wires, and with the X(Y) planes offset onehalf cell from the X (Y) cells. Each cell is 10 mm x 8 mm with grounded anodes (sense wires) and with cathodes (field wires) held at high negative voltage. The chamber used argonethane gas mixed 50:50 by weight. The readout+,,, electronics were LeCroy 2735 DC preamplifier/discriminator cards. A report will be given on chamber construction and performance.  ?   205 Name of Presenter: Michael Moore Institution: Hampton University Classification: Graduate Student Major Area of Study: Nuclear Physics NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Oliver K. Baker Construction of the High Momentum Spectrometer Drift Chamber The Experimental Nuclear Physics Group at Hampton University is responsible for building and maintaining three multiwire drift chambers for the High Momentum Spectrometer (HMS) at the Continuous Electron Beam Accelerator Facility (CEBAF). These drift chambers have an active area of 110 cm x 50 cm. There are six planes (XYUVY X) per chamber with the UV stereo planes inclined at 15$ with respect to the X and X planes. The X(Y) plane is offset onehalf cell from the X(Y) plane. Each cell is 10mm x 8 mm and has a 5 mm drift distance. The field wires (cathodes) are 150 m goldplated copperberyllium wire while the sense wires (anodes) are 25 m goldplated tungsten. The chamber uses argonethane gas mixed 50:50 by weight. A report will be given on the chamber construction details and on preliminary chamber performance results.  ?p  206 Name of Presenter: Shelia NashStevenson Institution: Alabama A&M University Classification: Graduate Student Major Area of Study: Physics NSF Sponsored Program: MRCE Faculty Advisor: Dr. Putcha Venkateswarlu  Bx Energy Upconversion in MF2:Nd3+ (where M=Ca, Sr or Ba)  C Laser induced fluorescence is recorded in MF2:Nd3+ (where M = Ca, Sr or Ba) single crystals by exciting them with Ar+ and dye laser  C! wavelengths. When the D levels of Nd3+ are resonantly excited upconverted fluorescence is detected from the higher K, L and other levels. These results will be discussed in detail.  ?%  207 Name of Presenter: Garfield Pearcy Institution: Alabama A&M University Classification: Graduate Student Major Area of Study: Materials Science NSF Sponsored Program: MRCE Faculty Advisor: Dr. M.D. Aggarwal+,,,Ԍ ?  ÙTop Seeded Solution Growth and Characterization of Barium Titanate  B BaTiO3 Crystals  C[ Barium titanate, BaTiO3, is an important photorefractive material for a variety of applications that include optical phase conjugation and signal processing. For crystal growth of these crystals, top seeded solution growth system has been designed and fabricated in the laboratory. This system consists of a resistance heated, cylindrical furnace capable of temperatures up to 1540$C and a crystal rotation and pulling arrangement. According to the phase diagram, 65% titanium oxide mixed with 35% barium oxide melts at 1400$C. After initial homogenization, a seed is brought in contact with the melt and slowly pulled at a rate of 0.1 mm/h and rotated at a speed of 50 rpm. We have been able to grow crystal boules weighing 17 g of barium titanate crystals. Photorefractive studies will be carried out on these crystals in the laser laboratories and the results will be presented. 208 Name of Presenter: Peter E. Radcliff Institution: Virginia State University Classification: Graduate Student Major Area of Study: Physics NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Carey Stronach Muonium and Muonated Radical Formation in Carbon 70 Molecules Muons from the TRIUMF cyclotron were implanted into powder and disk C70 samples. Measurements made at several applied magnetic fields showed that muonium is formed, along with three muonated radicals, which displayed distinct bonding to the C70. The locations of these bonds and problems related to solvent contamination of the samples will be discussed.  ?  209 Name of Presenter: Rhonda Reid Institution: City College of New York Classification: Graduate Student Major Area of Study: Physics NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Daniel L. Akins Classical Theory of Normal Mode Calculations Classical treatment of the molecular vibrational problem is derived from Lagrange's equation of motion. Matrix manipulation via a symbolic program such as MatLab is utilized. The potential energy matrix is expressed in terms of internal coordinates and subsequently transformed into Cartesian displacement coordinates. The vibrational secular equation is expressed in terms of the potential energy, and vibrational frequencies are calculated by diagonalizi*,,,Ԯng the secular equation. The vibrational frequencies are used to determine energy eigenvalues and eigenvectors. Model systems, including carbon dioxide, porphyrins, and prototypical cyanine dye, have been treated.  ?  210 Name of Presenter: Virgil B. Shields Institution: Howard University Classification: Graduate Student Major Area of Study: Electrical Engineering NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Michael G. Spencer Near Equilibrium Growth of Thick, High Quality BetaSiC by Sublimation A close spaced nearequilibrium growth technique was used to produce thick, high quality epitaxial layers of beta silicon carbide. The process utilized a sublimation method to grow morphologically smooth layers. The beta silicon carbide growth layers varied from about 200 to 750 microns in thickness. Chemical vapor deposition grown, 210, micron, beta silicon carbide films were used as seeds at 1860$C and 1910$C growth temperatures. The respective average growth rates were 20 and 30 microns per hour.  CP The layers are ptype with 3.1 x 1017cmé3 carrier concentration. Electrical measurements indicate considerable improvement in the breakdown voltage of Schottky barriers on growth samples. Breakdown value ranged from 25 to 60 volts. These measurements represent the highest values reported for 3CSiC.  ?  211 Name of Presenter: Dawn Stephens Institution: Clark Atlanta University Classification: Junior Major Area of Study: Physics NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Professor Herbert Winful Spectroscopic Measurement of Emission in a Neodymium Doped Fiber Pumped at 1.064 Microns We present the results of spectroscopic measurements on Neodymium doped silicate fiber. The phenomenon of emission in the visible (470 nm, 650 nm, and 780 nm) when pumped by 1.064 %m occurred. Results are compared to those of an undoped silicate fiber. Possible explanation for these emissions are discussed. In our experiment, we pumped the fiber with a modelocked Nd:Yag laser. The pulses were 100 ps in duration at a repetition rate of 76 MHz. Average power was varied between 50 mW and 3 W. Measurements were made with a monochromator using a photomultiplier tube and a photon counter. Threshold average pumping power of between*,,, 50 mW and 100 mW was required to obtain emission at 470 nm and 650 nm. However, the 780 nm emission had a threshold below 50 nW.  ?   212 Name of Presenter: Mechelle Taylor Institution: Meharry Medical College Classification: Graduate Student Major Area of Study: Neurophysiology NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Hubert K. Rucker The Effect of Glutamate and GABA Microdialysis into the Basal Forebrain on Feature Abstraction in the Rat Auditory Cortex The specific aim of this study was to determine the effects of basal forebrain activity, as modulated by the microdialysis of glutamate and GABA, on information processing in the auditory cortex of the rat. One hundredtwenty one single neurons isolated in the auditory cortex of urethane anesthetized rats were characterized with regard to their frequency receptive fields and rateintensity functions during artificial cerebral spinal fluid (aCSF), glutamate + aCSF, and GABA + aCSF microdialysis into the basal forebrain. Approximately 61% (n=16) of the neurons in the rate intensity study exhibited lowered thresholds and increased gains in the presence of glutamate. The administration of GIBBET mainly caused a decrease in rate intensity functions by increased response thresholds. In the receptive field study, both glutamate and GABA exhibited heterogenous modifications. Glutamate predominantly increased 46% (n=18) of neurons' best frequency (BF) responses along with an enhancement of nonBF responses. GABA mainly decreased 50% (n=15) of neurons' BF responses; however, nonBF responses were facilitated. These data confirm that the basal forebrain projection system is capable of "gating" and switching the sensory information transfer in the auditory cortex.  ?@  213 Name of Presenter: Anthony Walker Institution: Howard University Classification: Senior Major Area of Study: Biology NSF Sponsored Program: MRCE Faculty Advisor or Mentor: Dr. Michael G. Spencer Beta Silicon Carbide Grown on Silicon SiC has recently attracted attention for device application because of its special properties such as chemical inertness, high thermal conductivity, radiation hardness, wide bandgap, high breakdown field, and large saturation velocity. In this report, we will outline and discuss the details of the growth of beta silicon carbide grown by both horizontal and vertical chemical vapor+,,, deposition (CVD) techniques on (100) silicon (Si) substrates. Both undoped and doped samples were grown and measured. The sample thickness range from 6 % to 28 %. The as grown material was highly  CX compensated (Nd = 5.9 x 1018 cmé3 and NA = 5.8 x 1018 cmé3) with a donor level at in the 6 22 meV range. We will also report on the successful fabrication of a several electronic devices made from this material.  ?   214 Name of Presenter: Juan White Institution: Howard University Classification: Graduate Student Major Area of Study: Solid State Materials NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. G. L. Harris Ion Implantation into Cubic SIC with Device Applications Ions of beryllium, aluminum, boron, arsenic, and nitrogen were implanted into (100) oriented SIC at room and elevated temperatures. The SIC thin films were grown by reduced pressure CVD on silicon substrates. In this paper, we will report on the electrical properties of these implanted films. Measurements indicating the activation percentage and type will be discussed in detail. Capacitancevoltage, sheet resistances, and mobility measurements were performed on the rapid thermal annealed samples. The authors will also discuss the applicability of these results to SIC device fabrication.  ?  215 Name of Presenter: Erica M. Whitney Institution: Spelman College Classification: Junior Major Area of Study: Chemistry NSF Sponsoring Program: MRCE Faculty Advisor or Mentor: Dr. Beatriz H. Cardelino Prediction of the Dispersion Effects on the SecondOrder Polarizability of Organic Molecules Certain molecules, when placed in an electric field and illuminated by a light with energy less than their excitation or absorption energy, can double the energy of the incident beam. Dispersion effects on secondorder polarizabilities can be determined experimentally but may also be predicted using known theories. The basis for predicting the dispersion effects of secondorder polarizabilities is time dependent perturbation theory. These calculations require extensive computations. To predict dispersion effects for large organic molecules, considerable approximations must be done. The effect of laser frequency on the secondorder polarizability was estimated for pnitroaniline, aniline, and nitrobenzene with nitro group coplanar or perpendicular to the aromatic ring. The*,,, dispersion effects were estimated for these molecules in order to estimate the quality of the approximations.,,,  ? ` `   OTHER NSF RESEARCH PROGRAMS  ?X  216 Name of Presenter: Viola L. Acoff Institution: University of Alabama at Birmingham Classification: Graduate Student Major Area of Study: Materials Engineering NSF Sponsoring Program: MPS Faculty Advisor or Mentor: Dr. Raymond G. Thompson  ?`  Effect of Heat Treatment on Microstructure and Microhardness of  ?( Spot Welds in Ti14Al21Nb The gas tungsten arc welded fusion zone of Ti14 wt.%Al21 wt%Nb was investigated to determine the effect that postweld heat treatment (PWHT) had on its microhardness and microstructure. The aswelded fusion zone consisted of an omegatype, "tweedlike", microstructure with a microhardness that was higher than the base metal. Short PWHT times at 650$C resulted in secondary hardening above that of the aswelded condition while longer times resulted in hardness values near that of the base metal. Only heavily  C faulted 2 was detected in the 650$C PWHTs. The 980$C PWHT had microhardness and microstructure similar to the 650$C, 1 minute 50 hours PWHT. All other PWHTs at 980$ had microhardness values near that of the base metal. The microstructure for these PWHTs  C consisted of 2 grains with B2 precipitates. 217 Name of Presenter: Molly M. R. Bryson Institution: University of Maryland, College Park Classification: Graduate Student Major Area of Study: Systems Engineering NSF Sponsoring Program: ENG Faculty Advisor or Mentor: Dr. John S. Baras Hybrid Cellular-Satellite Network Simulation Cellular-Satellite Handovers As technological advances are made in the world, communication needs tend to extend with the technology available. The area of mobile communications is an avenue which has potential for very rapid growth. Many companies are participating in ventures, experiments and developments that will expand the area of mobile communications globally. At the University of Maryland, Systems Research Center, we would like to be involved in these efforts, particularly in the area of Hybrid Cellular-Satellite Communication Networks. This paper discusses progress made researching cellular systems, satellite systems and the networking between them. The functionality of the cellular systems and the satellite systems is explained, followed by the description of a simulation study involving the handover aspect between the cellular and satellite systems. Within the description of the simulation study, the+,,, entity roles and relationships are described. Finally, the current status of the project is reported. 218 Name of Presenter: Isaac Chappell Institution: Florida A&M University Classification: Junior Major Area of Study: Physics NSF Sponsoring Program: Mathematical and Physical Sciences (MPS) Faculty Advisor or Mentor: Dr. Joseph O'Gallagher Cesium Iodide Scintillator Crystal Testing for E832 at Fermilab During the summer of 1992, I worked with the CP-Violation group at the University of Chicago as part of a new research program. While there, I helped in the testing of CsI crystals for the new detector being built for experiment E832 which will be running at Fermilab around 1994-1995. 219 Name of Presenter: Ana DePina Institution: Wellesley College Classification: Graduate Student Major Area of Study: Biology NSF Sponsoring Program: Biological Sciences (BIO) Faculty Advisor or Mentor: Mary M. Allen Phosphorus Starvation and Nuclear Magnetic Resonance Studies of the Cyanobacterium, Synechocystis 6308 The effect of phosphorus starvation on growth, phycobilisome content and composition, and cyanophycin granule content of Synechocystis sp. strain 6308 was observed. Growth stopped after 24-30 hours in phosphorus-free medium; phycobilisome content decreased and cyanophycin granule polypeptide content increased upon starvation. The phycobilisome polypeptide composition was similar to phosphorus-replete cells and antibody raised to the 27- kDa phycobilisome linker polypeptide bound to a 27-kDa polypeptide from phosphorus-replete and -starved cells, suggesting similar properties were preserved. In vivo phosphorus-31 nuclear magnetic resonance spectroscopy and carbon dioxide fixation have been demonstrated to be effective means to assess cell viability. Phosphorus-31 spectra have revealed numerous phosphorus-containing metabolites, including inorganic phosphate, sugar phosphates, polyphosphate, and adenosine nucleotides; carbon dioxide fixation has disclosed relative amounts of bicarbonate uptake in cells that are and are not actively photosynthesizing. (Emmanuel College) 220 +,,,ԌName of Presenter: Winford L. Hill II Institution: North Carolina State University Classification: Graduate Student Major Area of Study: Electrical Engineering NSF Sponsored Program: Engineering (ENG) Faculty Advisor or Mentor: Dr. Peter McLarty Study of Alternative Gate Dielectrics One of the most important limitations in modern VLSI circuits is the formation of high quality thin gate dielectrics. As an undergraduate, the thrust of my research was in understanding the breakdown characteristics of oxides as gate dielectrics. Since breakdown events are probabilistic in nature, measurements must be performed over a large number of devices to get reliable data. A completely automated system to test the devices and analyze the data was developed. The three tests performed by this system are charge to breakdown, time to breakdown, and ramped voltage breakdown. Automation of these tests have resulted in a more reliable test environment which allows more accurate characteristics to be derived. As a graduate student, my research will be focused on analyzing the suitability of deposited oxynitride films as gate dielectrics. Breakdown characteristics will be measured along with CV and IV measurements. 221 Name of Presenter: Brianna L. Hinojosa Institution: Trinity University Classification: Junior Major Area of Study: Engineering Science NSF Sponsoring Program: Engineering (ENG) Faculty Advisor or Mentor: Dr. L. S. Fletcher Offshore Technology Research Center REU Ethics Forum: Development of Hypothetical Ethics Case Studies in Offshore Technology The Offshore Technology Research Center's Summer Undergraduate Research Program included an REU Ethics Forum to develop hypothetical ethics case studies related to offshore technology. During the tenweek period, the students met on a weekly basis to hear lectures and watch videos which consisted of problems one might encounter in the engineering profession. The group broke up into four small groups to discuss and develop hypothetical case studies. The four case study topics developed by the groups included: (1) Professionalism and Women Engineers (2) The Manager/Engineer Conflict (3) Offshore Oil Production and the Environment (4) Confidentiality and Proprietary Information The four cases involved situations with various options for the engineer to take. At the end of the summer program, the cases were presented and videotaped to introduce these ethical issues to future engineers, stressing the decisionmaking process. +,,,ԌThis presentation will describe the ethics cases that were developed in the Offshore Technology Research Center REU Ethics Forum.  ?  222 Name of Presenter: Oscar Kawagley Institution: University of Alaska Fairbanks Classification: Graduate Student Major Area of Study: Social and Education Policy NSF Sponsoring Program: GEO Faculty Advisor or Mentor: Ray Barnhardt Science in a Yupik Fish Camp and School This presentation analyzes the articulation between Yupiaq and Western ways of knowing. It will focus on the setting of a Yupiaq fish camp and community which reflects traditional Yupiaq ways of knowing about their world, and examine how the Yupiaq use their own principles of science and/or adapt Western science and technology to fit their everyday needs. It will address the school's science education program to determine to what extent it incorporates local resources, knowledge and practices, and if local cultural and environmental needs are incorporated. As a result of the juxtaposed settings of science learning and practice in the community and school, common themes and contrastive approaches will be identified which will lead to a conceptual integration of the multiple ways of teaching and learning of scientific knowledge, attitudes and skills for the Yupaiq and other Native peoples. 223 Name of Presenter: Karen D. King Institution: University of Maryland, College Park Classification: Graduate Student Major Area of Study: Mathematics NSF Sponsored Program: GERD Faculty Advisor: Dr. Raymond Johnson Error Correcting Codes In everyday life we see the effects of codes. When the longdistance phone call is made, the satellite television show is turned on or various other communication forms happen, the user of codes is evident. A code is a transmission of a message from one place to another, usually secretly, so no one else can receive it and understand it. However, if the code is received through long distances, has mistakes, even the intended receiver cannot read it through decoding. Hence there are codes which can detect and correct errors in transmission. One example of a code of this type is the BoseChaudhuriHocquenghem or BCH code which will be studied here. It is a form of polynomial code which uses polynomials to transmit and receive messages. +,,,Ԍ224 Name of Presenter: Carl Matthews Institution: University of Texas at Austin Classification: Senior Major Area of Study: Chemistry NSF Sponsoring Program: STC Faculty Advisor or Mentor: Dr. John M. White Study of Variations in Porous Silicon Photoluminescence with Temperature and Hydride Coverage The photoluminescence of anodically etched porous silicon was observed as a function of temperature and surface hydride coverage. The surface hydride coverage was quantified using Fourier Transform Infrared Spectroscopy by measuring the area of the peaks corre C sponding to the stretching frequencies of SiH and SiH2. A monochromator and photomultiplier tube were used to take photoluminescence (PL) spectra of the UVirradiated silicon samples. At constant hydride coverage, there was a marked decrease in light emission as well as the frequency of the PL maximum as the sample was heated from 146K to room temperature. This data indicates that the probability of radiative transfer is enhanced by cooling. Upon heating the samples above 560K, the samples began losing surface dihydride by decomposition to SiH and desorption of dihydrogen, with the most substantial drop in coverage occurring around 590K. Although the luminescence intensity began to decrease before the loss of surface hydrogen, the peak frequency of light emission decreased as the hydrogen desorbed. The Pl spectra have peaks at 710nm and 760nm. The presence of these peaks suggests that two distinct chemical species are causing the luminescence.  ?  225 Name of Presenter: Stanley D. Merritt Institution: Texas A&M University Classification: Graduate Student Major Area of Study: Civil Engineering NSF Sponsoring Program: Engineering (ENG) Faculty Advisor or Mentor: Dr. Bill Batchelor Applications of Soil and Cement Chemistry to Stabilization/Solidification The main objective of stabilization/solidification (S/S) is to add binders to a waste or contaminated soil to reduce the mobility of toxic contaminants. Immobilization can occur by either physical or chemical means. Physical immobilization occurs when the contaminant is encapsulated in a solid matrix. Chemical immobilization occurs when the contaminant is converted by chemical reaction to a less mobile form. Precipitation and adsorption are examples of chemical processes that can lead to immobilization. Physical processes in S/S have received the greatest attention and more data is available on the physical characteristics of treated material. Measurements such as plasticity index, unconfined compressive*,,, strength, freeze/thaw durability, wet/dry durability and shrinkage/swell potential are often conducted. The chemical processes associated with S/S have received less attention, particularly those processes that affect contaminants. This paper will discuss applications of cement and soil chemistry to S/S technology. The relative importance of kinetics and equilibrium of chemical processes in S/S will be examined. Equilibrium chemistry will be presented as a practical method for describing how reactions between binders and soil produce the chemical environment that determines whether contaminants will exist in mobile or immobile forms. Chemical processes such as hydrogen exchange, precipitation, and sorption will be reviewed in terms of their importance to chemical immobilization of contaminants. The use of chemical equilibrium programs such as SOLTEQ will be discussed. SOLTEQ is a modification of an EPAsupported program (MINTEQ) that is applicable to cementitious/pozzolanic systems such as soils or wastes treated by S/S. It can calculate concentrations of contaminants in both mobile and immobile phases and provides a mechanism to integrate chemical information from a variety of systems. The importance of pozzolanic reactions to developing the chemical environment in wastes and soils treated by S/S will be described. The role of solid cation exchange capacity effects on water binding capacity will also be discussed and the implications of these processes on mix design will be reviewed.  ?  226 Name of Presenter: Sonya T. Smith Institution: University of Virginia Classification: Ph.D. Student Major Area of Study: Theoretical and Computational Fluid Dynamics NSF Sponsored Program: Engineering (ENG) Faculty Advisor or Mentor: Dr. Hossein HajHariri  ?  A Weakly Nonlinear Analysis of G?rlter Vortices and Heat Transfer A weakly nonlinear analysis of the G?rlter vortex problem is performed. It is demonstrated that the system of streamwise vortices enhances the heat transfer rate at the wall. The inherentlynonlinear physical mechanism responsible for this enhancement is discussed mathematically as well as heuristically, using kinematic arguments. Remarks are made on the compatibility of the weakly nonlinear results with their fullynonlinear counterparts, as well as the inadequacy of linear analyses. 227 Name of Presenter: Hazel Spears Institution: Princeton University Classification: Graduate Student Major Area of Study: Social Psychology NSF Sponsoring Program: Graduate Education and Research Development (GERD) Faculty Advisor or Mentor: Dr. John Jemmott +,,,Ԍ ?  ÙReactions to Preferential Treatment: An Investigation of Affirmative Action Undergraduate subjects (N=250) were asked to indicate on a 1-5 ratings scale how much they agreed with one of 10 different preferential treatment situations. The ten situations were: farm subsidies, welfare, disaster relief, affirmative action for women, affirmative action for Blacks, preferential treatment for veterans, union members, athletes in college placement, children of alumni, and in-house hiring. Respondents were also asked to rate their perceptions of fairness, and the likelihood that they themselves or family members would benefit from such preferential treatment policies. An equity versus equality scale was also administered to determine whether subjects subscribed to a distributive norm of equity or equality. It was predicted that ratings of agreement would be lower for the two preferential treatment situations in which women and Blacks were recipients, compared to the eight other situations. It was also predicted that ratings of agreement for some preferential treatment situations (farm subsidies, welfare, affirmative action) would be higher for individuals who subscribed to a norm of equality, while ratings of other preferential treatment situations (athletes, children of alumni) would be higher for individuals who subscribed to a norm of equity. Both predictions were confirmed. 228 Name of Presenter: Alice R. Villalobos Institution: University of Arizona Classification: Graduate Student Major Area of Study: Physiology and Behavior NSF Sponsoring Program: Biological Sciences (BIO) Faculty Advisor or Mentor: Dr. Eldon J. Braun Organic Cation Transport by Avian Renal Brush Border Membranes Knowledge of the subcellular mechanisms of organic cation secretion by the avian kidney is limited. The ratelimiting step for organic cation secretion is at the luminal or brush border membrane of the vertebrate proximal renal tubule. We examined transport of the  C organic cation [14C]tetraethylammonium (TEA+) in brush border membrane vesicles (BBMV) isolated from proximal renal tubules of  C! domestic chickens. By rapid filtration we measured TEA+ transport  Ch" under various ionic conditions. TEA+ was transported via H+ or  C4# organic cation (OC+)exchange. TEA+ uptake via H+ exchange was inhibited by organic cations but not organic anions. Membrane  C$ potential had no direct effect on TEA+ transport. TEA+ transport  C% was indirectly coupled to Na+ transport. The kinetic parameters of  C`& TEA+/H+ exchange in avian BBMV are comparable to those for OC+/H+  C,' exchange in mammals. Our data indicate OC+ transport in avian renal BBMV is qualitatively and quantitatively similar to that in mammalian systems. 229+,,,Ԍ ?  ęName of Presenter: Wendy Ann Woodward Institution: Virginia Polytechnic Institute Classification: Senior Major Area of Study: Chemistry NSF Sponsoring Program: Science and Technology Centers (STC) Faculty Advisor or Mentor: Dr. Ron Kriz Chemical Applications of Computer Simulation Software Hydrous and anhydrous 30-c-10 crown ether macrocycles have been identified as well-suited to the synthesis of rotaxanes and polyrotaxanes due to their ease in synthesis, inexpensive starting materials, and relatively high yields. Cyclo bis(oxyterephthaloyloxy-1, 4-phenyleneisopropylidene-1,4-phenylene) (CTP) and cyclo bis(oxyisophthaloyloxy-1,4-phenyleneisopropylidene-1,4-phenylene) (CIP) are two semi-rigid macrocycles well-suited to polyrotaxane synthesis. It was ascertained that the macrocycles studied all retained their cavities in their minimum energy state. Anhydrous 30-c-10 yielded a total energy = 54.768 Kcal/mol, and a cavity = 4.86A x 13.6A. This compares favorably to the cavity size observed by Xray crystallography, 3.9A x 13.6A. 30-c-10 : 4H2O shows a much lower total energy = 10.32 Kcal/mol and a cavity = 11.83A x 6.49A. The great difference in energy is due to hydrogen bonding. Dissimilarities were observed between the Xray structure and the Polygraf visual, suggesting a lower global minimum has yet to be found. CTP's total energy = 177.84 Kcal/mol and the cavity = 13.09A x 7.16A while CIP's total energy = 170.638 Kcal/mol and the cavity = 11.24A x 9.13A. The energies of the semi-rigidmacrocycles are fairly comparable as expected given the strong similarity in their structures. The shortest distance across the cavity was used in cavity measurements.  ?  230 Name of Presenter: Leon Wooten Institution: Texas A&M University Classification: Graduate Student Major Area of Study: Biology NSF Sponsoring Program: Biological Sciences (BIO) Faculty Advisor or Mentor: Dr. Robert Elder Regulatory Sequences for Meiosis-Specific Expression in Yeast Meiosis produces the haploid gametes necessary for sexual reproduction in eukaryotes. The central events of meiosis are recombination between homologous chromosomes and the reductional chromosome division which generates genetic diversity and the correct number of chromosomes. Studies in the simple eukaryote yeast have identified a class of genes which are specifically induced during meiosis and whose products are necessary for recombination and the reductional division. Experiments with one on these genes (SPO16) are defining the sequences necessary for meiosis-specific expression. These sequences include a repressor element which surprisingly is present in many other yeast genes not involved in meiosis. A series of deletions indicates that an activation sequence is located immediately adjacent to this repressor element. Our ultimate goals are to understand how the repressor and activator+,,, interact to give meiosis-specific expression in yeast and to determine if similar regulatory mechanisms operate during meiosis in higher eukaryotes. ,,, x!INDEX OF PRESENTERS,,, I N D E X STUDENT PRESENTERS  ?  COMPREHENSIVE REGIONAL CENTERS FOR MINORITIES (CRCM) Augusto, Samori 1 Banegas, Adrian 2 Barraza, Alma A. 10 Bautista, Raul 3 Billedeaux, Tina 4 Byrd, Kamafi 5 Campbell, Kendall 6 Clairmont, Shannon 4 Diaz, Nivia Col;n 7 Dunn, Chastity 8 Francisco, Dale 8 Gonzales, Jesus 9 Gutierrez, Aaron 10 Hurtado, Guillermo 11 Ivicek, Mike 3 Manning, Howard 12 MarreoMedina, Miguel E. 13 McFee, Joe 11 Minus, Timothy 14 Moore, Jerri 15 Reyna, Rene 16 Sandoval, Melanie 17 Sims, Melody 18 Sola Soto, Hilda M. 19 Tabullo, Jennifer 20 Taylor, Bridgette 21 Villegas, Rafael Marcos 22 X,,,  ?  ALLIANCES FOR MINORITY PARTICIPATION (AMP) Acosta, Juan M. 23 Allen, Carl 24 Aparicio, Ayde 25 Archie, Shirleceia 26 Arellano, Leonel 27 Bouroncle, Ramiro 28 Burgess, Roderick F. 29 Channell, Khalid 30 Concepci;n, Jessica Gaspar 31 Cruz, Rub)n Le;n 32 Davis, Jerome E. 33 D1az, Vanessa 34 Doyle, Cynthia 35 Falcon, Robert 36 Fontan, Gary P. 37 Garcia, Rachel 38 Gonzales, Eric 39 Granado, Cynthia 40 Harris, Audray K. 41 Hooks, Denise 42 Jackson, Kimberly L. 43 Johnson, Curtis 44 Lay, Sharon 45 Lee, Renee 46 Lock, Ericka N. 47 Long, Tamara M. 48 Maga9a, Daniel 49 Martinez, Araceli 50 Matthews, Manyalibo 51 McHellon, Sharoon 52 Miranda, Gustavo 53 Olivier, Lisa M. 54 Palmer, Carl III 55 Pilliner, Ramona 56 Santana, Luc1a M. JesCs 57 Simchen, David 58 Torres, Ivn O. Rivera 59 Waldon, Ila 60 Wyatt, Marilyn D. 61  ,,,  ?  RESEARCH CAREERS FOR MINORITY SCHOLARS (RCMS) Acosta, Felipe J. 62 Amarao, Elias 63 Angus, Stanley 64 Asensio, Maria Cristina 65 Bartley, R. Christian 66 Beatie, Matthew E. 67 Bedoy, Chris 68 Benally, Francene R. 69 Bland, Jormell F. 70 Bonilla, Yara I. Alma 71 Borgia, Alejandro 72 Casanas, Vivian Rosa 73 Cerda, Paul 74 Chacon, Carlos 75 Clinton, Tobi 76 Cordova, Ricko 77 Davis, Byron 78 Davis, Michael A. 79 Dike, Julie 80 Dixon, LaShondria B. 81 Donatto, Ursula 82 Edwards, Tracy T. 83 Emanuel, Ako 84 Enriquez, Ruben 107 Ferris, Joy E. 85 Figueroa, Harold K. 86 Figueroa, Iddys D. 87 Fisher, Michael 88 Franklin, Dionne M. 89 Gaffney, Brian 90 Graham, Darelene 91 Griffin, Malaika T. 92 Guiteau, Jacquelin 93 Hampton, Chenita D. 94 Hart, Antonio 95 Heath, Mikita L. 96 Himaya, Amalia C. 97 Hodge, Vermettya 98 Holbrook, Jarita C. 99 Holzer, Charles 100 Hurtado, Maria T. 101 Jackson, Kimberly 102 Jones, Marcia 103 Joyce, Patrick F. 104 Kennedy, Lesa 105 Lee, Jabari 106 Martinez, Juan 107 Matus, Obed II 108 McCorkle, Lucy 109 McDonald, Russell 110 McMullin, Vaughn 111 Mealing, Angelette 112 Merriman, Vanda W. 113 Moffett, Crystal 114 Monzon, Franklin 115+,,,ԌNozie, Vern 116 Otero, Miria F. 117 Panchula, Martin L. 118 Pearson, Roderick 119 Pemberton, Roy, Jr. 120 Penn, Michael L., Jr. 121 Portillo, Mauricio 122 Quam, Andrew 123 Rambeau, Kenya 124 Ramirez, Rebecca O. 125 Redrick, Phillip Lamont 126 Rhodes, Hue 127 Rice, Kimberly N. 128 Rivas, Matt 129 Rolle, Marchant D. 130 Russell, Ericka 131 Sanchez, Louis 132 Scott, Alexis M. 133 Shakoor, Aliyah 134 Sheppard, Wilson J. 135 Smith, August L. III 136 Spears, Michael 137 St. Julien, Shawna 138 St. Prix, Courtney 139 Staples, Tiffany 140 Stoneham, Leslie 141 Suarez, Mitchell 142 Swint, Tracy 143 Thomas, Maceo 144 Thomas, Paul 145 Thorpe, Sandra 146 Turner, Shawn 147 Vegara, Billy J. 148 Walker, Felicia 149 Walters, Wilbur 150 Warren, Aundrea 151 Washington, Jarvis 152 Watson, Patricia 153 Weckwerth, Karl 154 Weems, Kimberly S. 155 Wilcox, Reginald B. 156 Williams, Jenae D. 157  ,,,  ?  RESEARCH IMPROVEMENT IN MINORITY INSTITUTIONS (RIMI) Akinniyi, Olushola M. 158 Appiah, Kwadwo 159 Ashley, Andrea 160 Barnwell, Lyndon F. 161 Boone, Michele 162 Borris, Frank S. II 163 Castellanos, Angel 164 Estrada, Leticia Y. 165 Freemont, Andria 166 Garcia, G.V. 167 Gonzalez, Hector R. 168 Hawkins, Timothy A. 169 Hopkins, Calandra 170 King, Jeffery F. 171 Matlock, Dixie J. 172 McClellan, Carlee 173 Nieves, Reinaldo G. 174 Nelson, Charles 175 Page, SaJean H. 176 Parizon, Michael 177 Ramirez, John G. 178 Richardson, Nathan L. 179 Robinson, Timothy 180 Santiago, Ivonne 181 Simpson, Keithia 182 Tate, Angela S. 183 Wheeler, Zachary 184 Will, Anthony B. 185 Wilson, Gayla 186 8,,,  ?  MINORITY RESEARCH CENTERS OF EXCELLENCE (MRCE) Adorno, Carlos 187 Brown, Kenneth A. 188 Brun, Mari Carmen 189 Bryant, William 190 Carpenter, Agnes 191 De Lugo, Monica M. 192 Deosaran, Shelley 193 Edwards, Andrew G. 194 Galarza, J.R. 195 Garbalena, Manuel 196 Gonzalez, Ismael E. 197 Johnson, Alicia 198 Jones, Isaac 199 Joshua, Jaime 200 Lewis, Jonathan H. 201 Linder, Kojo 202 Looney, Kimberly 203 McCauley, Angela 204 Moore, Michael 205 NashStevenson, Shelia 206 Pearcy, Garfield 207 Radcliff, Peter E. 208 Reid, Rhonda 209 Shields, Virgil B. 210 Stephens, Dawn 211 Taylor, Mechelle 212 Walker, Anthony 213 White, Juan 214 Whitney, Erica M. 215 8,,,  ?  OTHER NSF RESEARCH PROGRAMS Acoff, Viola L. 216 Bryson, Molly M. R. 217 Chappell, Isaac 218 DePina, Ana 219 Hill, Winford L. II 220 Hinojosa, Brianna L. 221 Kawagley, Oscar 222 King, Karen D. 223 Matthews, Carl 224 Merritt, Stanley D. 225 Smith, Sonya T. 226 Spears, Hazel 227 Villalobos, Alice R. 228 Woodward, Wendy Ann 229 Wooten, Leon 230 H ,,, *,,, ` `  hh#XX%(-pp2NSF 9347 (new)