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For almost two decades, engineers have been able to create models directly from computer drawings, layer by layer, with Solid Freeform Fabrication technologies. One method, Three Dimensional Printing (3DP^TM) shows promise for the direct manufacture of goods ranging from bone grafts to automobile parts.

Emanuel Sachs and colleagues at the Massachusetts Institute of Technology developed 3DP^TM with support from NSF and other federal agencies. Currently, five independent companies are pursuing 3DP^TM applications.

The process is based on the understanding that any shape can be built from stacked layers, "Think Pyramids at Giza," said Sachs. In 3DP^TM, the 30 to 200-micron layers are comprised of powdered ceramic, metal or plastic composites. Ink jets apply a binder between each subsequent layer after it is deposited. The resulting structures can be highly complex, with complicated internal geometries that would be difficult to machine using standard engineering methods.

Direct manufacture applications already in development include scaffolding for human tissue grafts, chambered pills that contain multiple drugs, ceramic molds, metal parts, filters for power plants and electronic components. NSF originally funded the research to address manufacturing issues, specifically the potential for prototyping as an all-in-one process, said George Hazelrigg, a program director within the NSF engineering directorate. "Now, it has spinoffs with a big impact in medicine," particularly because rapid prototyping is one of the best methods for manufacturing tissue scaffolding, he said. [Josh Chamot]

New Approaches to Training Engineers --
In addition to advancing 3DP^TM technology, Sachs has been developing a new method for instructing the next generation of engineers. See the sidebar for more information and graphics.

This 3DP^TM model of the dome at MIT's Great Hall demonstrates the intricacy and detail possible with the process.
Photo Credit: MIT 3DP Lab
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By using different printer jets to produce different parts, the 3DP^TM technology is capable of creating color-coded objects, such as this model of a compressor.
Photo Credit: MIT 3DP Lab
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For additional information on 3DP^TM, see: http://www.mit.edu/~tdp/ and
http://www.eng.nsf.gov/engnews/

This photo shows a ceramic mold made by 3D Printing and an orthopedic knee casting poured into a similar mold. The knee casting has been polished on the back side as can be seen in the reflection in the mirror. The casting is made of a medical cobalt chrome alloy.
Photo Credit: MIT 3DP Lab
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This photo shows a family of injection molding tools made by 3D Printing. The tool in the lower left corner is approximately 150 mm long. Many of these tools have conformal cooling channels printed within them. Such channels lead to far better temperature control during the injection molding resulting in faster production and high quality parts.
Photo Credit: MIT 3DP Lab
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This object was printed directly from a mathematical model and would be extremely difficult to manufacture by conventional techniques. It is intended as an illustration of the geometric capability of 3D Printing. This model was made by Z Corp., maker of what are said to be the world's fastest 3D printers.
Photo Credit: Z Corporation
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This photo shows a ceramic filter made by 3D Printing. The cut away shows the internal passages created as part of the printing process. 3D Printed filters are being applied to the clean-up of power plant emissions.
Photo Credit: MIT 3DP Lab
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Sound pioneer Tomlinson Holman, developer of the Lucasfilm THX Sound System^© used in thousands of movie theaters, recently received a 2001 Academy Award Certificate for Technical Achievement recognizing his more than two decades of research as an audio engineer at the forefront of movie theater acoustics and speaker technology.

In addition to developing THX - the name derived from Tomlinson Holman's eXperiment - Holman was lead developer of George Lucas's state-of-the-art cinema production facilities Skywalker Ranch and Skywalker Sound.

Now a professor and researcher at NSF's Integrated Media Systems Center (IMSC) at the University of Southern California, Holman is focusing on the next generation of cinema sound, especially the 10.2-channel surround sound system. The 10.2 system, designed for public and home theater use, uses 12 speakers in 10 locations, plus two subwoofers, to create a better sense of aural immersion.

The range of pitches and loudness for cinema sound have already exceeded the limits of human hearing and Holman believes sound space is the next frontier for audio research. Under the direction of Chris Kyriakakis and Holman, NSF's IMSC Immersive Audio Lab is researching methods to expand these spatial limits - what Holman calls "the Manifest Destiny of recorded sound."

"Here is where we can push the scientific envelope," said Holman of the Immersive Audio Lab, where he conducts his research. "Many people who hear of 10.2-channel sound say its crazy . . . that's exactly where we should be. Then when they actually hear it, they're astounded." [Josh Chamot]

For additional information, see: http://imsc.usc.edu

The graphic depicts a soldier in an immersive training environment. The environment uses 10.2 sound and high-resolution imagery to accurately simulate the acoustic and visual space of a combat setting.
Photo Credit: Image is property of the Integrated Media Systems Center (IMSC). Image courtesy of IMSC and DARPA.
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Setup of the 10.2-channel surround sound system, an immersive audio system being developed at NSF's Integrated Media Systems Center at the University of Southern California.
Photo Credit: Image is property of the Integrated Media Systems Center
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Fluorescent lights used in the Talking Lights^TM system.
Photo Credit: Image courtesy of Talking Lights^TM
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Handheld receiver used in certain applications of the Talking Lights^TM system.
Photo Credit: Image courtesy of Talking Lights^TM
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Inspired by the methods of his rural Kentucky high-school chemistry teacher, an NSF-supported researcher has developed an artificial intelligence tutoring software that helps students confront complex science questions.

In 1998, chemist Benny Johnson founded Quantum Simulations, Inc. with high school mentor Dale Holder and colleague Rebecca Renshaw to create highly interactive tutoring software for the sciences.

Many pre-existing tutoring programs store information in a database and do not allow for student input beyond multiple choice answers or simple responses. In contrast, the Quantum Tutors "converse" with students, said Johnson, "providing real-time feedback . . . Tutors respond to student questions, give hints, show correct next steps and even explain why a step is correct or incorrect using scientific principles."

Students can enter any problem and related work, and the Quantum Tutoring Engines will understand and analyze all of the material. Any mistakes are confronted individually, and the student and the "tutor" provide information to each other throughout the learning exercise.

"At each step of a solution, the computer is able to generate a set of questions that students can ask," said Sara Nerlove, a program manager in NSF's SBIR program. "This capability of Quantum Solutions' technology provides a degree of apprenticeship that goes beyond that available in a conventional tutor."

Quantum recently partnered with Holt, Rinehart and Winston (HRW) to include AI tutors as an Internet component in high school chemistry, physical science, and integrated science course materials, and middle school physical science materials. According to Renshaw, HRW is the first textbook publishing company to utilize AI technology for chemistry and physical science.

Quantum has been receiving NSF funding since 2000 through the SBIR program. Along with additional support from the Department of Education and various private awards, Johnson and Holder have developed six chemistry tutors based on their artificial intelligence technology. [Josh Chamot]

For additional information, see: http://www.quantumsimulations.com/home.html

This screen capture demonstrates the HRW/Quantum product for Balancing Equations. The product has an "Ask Questions" feature - a pull down menu that displays questions that change with each step the student takes.
Photo Credit: Holt, Reinhart, and Winston/Quantum Simulations, Inc.
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This screen capture demonstrates a key software feature that allows students to enter their own work throughout the tutoring process. The Quantum Tutor interprets the individual work and guides the individual to a completed solution.
Photo Credit: Holt, Reinhart, and Winston/Quantum Simulations, Inc.
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