Major benefits to system architecture would result if cooling systems for components could be eliminated without compromising performance. This book surveys the state-of-the-art for the three major wide bandgap materials (silicon carbide, nitrides, and diamond), assesses the national and international efforts to develop these materials, identifies the technical barriers to their development and manufacture, determines the criteria for successfully packaging and integrating these devices into existing systems, and recommends future research priorities. Table of Contents Front Matter Executive Summary Backgorund State of the Art of Wide Bandgap Materials Device Physics: Behavior at Elevated Temperatures Generic Technical Issues Associated with Materials for High-Temperatures... High-Temperature Electronic Packaging Device Testing for High-Temperature Electronic Materials Conclusions and Recommendations References Appendix A: Silicon as a High-Temperature Material Appendix B: Gallium Arsenide as a High Temperature Material Appendix C: High-Temperature Microwave Devices Appendix D: Biographical Sketches of Committee Members

Microwaves can be effectively used in the processing of industrial materials under a wide range of conditions. However, microwave processing is complex and multidisciplinary in nature, and a high degree of technical knowledge is needed to determine how, when, and where the technology can be most profitably utilized. This book assesses the potential of microwave technology for industrial applications, reviews the latest equipment and processing methods, and identifies both the gaps in understanding of microwave processing technology and the promising development opportunities that take advantage of this new technology's unique performance characteristics. Table of Contents FRONT MATTER EXECUTIVE SUMMARY INTRODUCTION MICROWAVE FUNDAMENTALS MICROWAVE SYSTEM INTEGRATION APPLICATION CRITERIA MICROWAVE APPLICATIONS CONCLUSIONS AND RECOMMENDATIONS REFERENCES APPENDIX

This is a reproduction of a book published before 1923. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book. ++++ The below data was compiled from various identification fields in the bibliographic record of this title. This data is provided as an additional tool in helping to ensure edition identification: ++++ Nondestructive Evaluation Of Metal Matrix Composites: Report Of The Committee On Nondestructive Evaluation Of Metal Matrix Composites, National Materials Advisory Board, Commission On Engineering And Technical Systems, National Research Council; Volume 413 Of Publication NMAB National Materials Advisory Board (U.S.). Committee on Nondestructive Evaluation of Metal Matrix Composites National Academies, 1983 Technology & Engineering; Material Science; Composite materials; Technology & Engineering / Material Science

High-temperature ceramic fibers are the key components of ceramic matrix composites (CMCs). Ceramic fiber properties (strength, temperature and creep resistance, for example)-along with the debonding characteristics of their coatings-determine the properties of CMCs. This report outlines the state of the art in high-temperature ceramic fibers and coatings, assesses fibers and coatings in terms of future needs, and recommends promising avenues of research. CMCs are also discussed in this report to provide a context for discussing high-temperature ceramic fibers and coatings.

Many of the aircraft that form the backbone of the U.S. Air Force operational fleet are 25 years old or older. A few of these will be replaced with new aircraft, but many are expected to remain in service an additional 25 years or more. This book provides a strategy to address the technical needs and priorities associated with the Air Force's aging airframe structures. It includes a detailed summary of the structural status of the aging force, identification of key technical issues, recommendations for near-term engineering and management actions, and prioritized near-term and long-term research recommendations. Table of Contents Front Matter Executive Summary Part I Problem Definition and Status of the Aging Force Part II Recommended Strategy and Opportunities for Near-Term and Long-Term Research References Appendix A: Synopses of Air Force Aging Aircraft Structural Histories Appendix B: Biographical Sketches of Committee Members

Ballistic Imaging assesses the state of computer-based imaging technology in forensic firearms identification. The book evaluates the current law enforcement database of images of crime-related cartridge cases and bullets and recommends ways to improve the usefulness of the technology for suggesting leads in criminal investigations. It also advises against the construction of a national reference database that would include images from test-fires of every newly manufactured or imported firearm in the United States. The book also suggests further research on an alternate method for generating an investigative lead to the location where a gun was first sold: "microstamping," the direct imprinting of unique identifiers on firearm parts or ammunition. Table of Contents Front Matter Executive Summary PART I: Context for Ballistic Imaging Analysis, 1 Introduction 2 Firearms and Ammunition: Physics, Manufacturing, and Sources of Variability 3 Firearms Identification and the Use of Ballistics Evidence PART II: Current Ballistic Imaging and Databases, 4 Current Ballistic Imaging Technology 5 Current Ballistic Image Databases: NIBIN and the State Reference Databases 6 Operational and Technical Enhancements to NIBIN 7 Three-Dimensional Measurement and Ballistic Imaging PART III: Implications for a National Reference Ballistic Image Database, 8 Experimental Evidence on Sources of Variability and Imaging Standards 9 Feasibility of a National Reference Ballistic Image Database PART IV: Future Directions, 10 Microstamping: Alternative Technology for Tracing to Point of Sale 11 Best Standards for Future Developments in Computer-Assisted Firearms Identification References Appendix A: Gun Enforcement and Ballistic Imaging Technology in Boston--Anthony A. Braga Appendix B: Biographical Sketches of Committee Members and Staff

U.S. Air Force (USAF) planners have envisioned that uninhabited air vehicles (UAVs), working in concert with inhabited vehicles, will become an integral part of the future force structure. Current plans are based on the premise that UAVs have the potential to augment, or even replace, inhabited aircraft in a variety of missions. However, UAV technologies must be better understood before they will be accepted as an alternative to inhabited aircraft on the battlefield. The U.S. Air Force Office of Scientific Research (AFOSR) requested that the National Research Council, through the National Materials Advisory Board and the Aeronautics and Space Engineering Board, identify long-term research opportunities for supporting the development of technologies for UAVs. The objectives of the study were to identify technological developments that would improve the performance and reliability of a /generation-after-nexta UAVs at lower cost and to recommend areas of fundamental research in materials, structures, and aeronautical technologies. The study focused on innovations in technology that would a /leapfroga current technology development and would be ready for scaling-up in the post-2010 time frame (i.e., ready for use on aircraft by 2025).

Materials Science and Engineering (MSE) R&D is spreading globally at an accelerating rate. As a result, the relative U.S. position in a number of MSE subfields is in a state of flux. To understand better this trend and its implications for the U.S. economy and national security, the Department of Defense (DOD) asked the NRC to assess the status and impacts of the global spread of MSE R&D. This report presents a discussion of drivers affecting U.S. companies' decisions about location of MSE R&D, an analysis of impacts on the U.S. economy and national security, and recommendations to ensure continued U.S. access to critical MSE R&D. Table of Contents Front Matter Executive Summary 1 Materials as Global Activity: Setting the Scene 2 Globalization of Materials Research & Development Activity 3 Benchmarking of Materials Science and Engineering R&D 4 The Regulatory Regime as a Driver 5 Assessing the Impacts of Materials Science and Engineering R&D Globalization 6 Conclusions and Recommendations Appendix A Committee Biographies Appendix B Presentations to the Committee at its Public Meetings Appendix C Global Trends in MSE Patents Appendix D Global Trends in Literature Authorship Appendix E Results of Community Poll Appendix F Superalloy Case Study Appendix G Environmental and Safety and Health Regulations Appendix H Defining 21st Century Defense Needs

Noteworthy progress has been made recently toward understanding and quantifying the smoke toxicity factors involved in fire hazard assessment. Such progress has led to increased attention to the significance of fire growth parameters for toxic hazard. Methodology has been proposed to use fire test data, including information on the toxic potency of smoke in engineering calculations for the assessment of overall fire hazard. Confidence in the methodology may evolve from comparison with full-scale fire tests as well as from human fire fatality experience. This report addresses fire modeling, fire testing, smoke toxicity testing, fire hazard assessment, and fire risk assessment. In the assessment of potential toxic hazards in the event of fires in mass transit vehicles, the report concludes that selection of candidate materials should be based on analyses using both toxicological and engineering considerations. Table of Contents Front Matter Executive Summary 1. Background 2. Fire Modeling 3. Fire Testing 4. Smoke Toxicity Testing 5. Toxic Hazard Assessment 6. Fire Risk Assessment Appendix A: Recommended Fire Safety Practices for Rail Transit Materials Selection Appendix B: Standard Terminology of Fire Standards Appendix C: Transit Vehicle Fire Experience Appendix D: Transit Vehicle Interior Materials Appendix E: Suggested Readings Appendix F: Curricula Vitae

The surface transportation system is vital to our nation's economy, defense, and quality of life. Because threats against the system have hitherto been perceived as minor, little attention has been paid to its security. But the world is changing, as highlighted by dramatic incidents such as the terrorist chemical attack on the Tokyo subway in 1995. As a consequence, security concerns are now attracting more attention?appropriately so, for the threat is real, and responding to it is hard. Although the surface transportation system is remarkably resilient, it is also open and decentralized, making a security response challenging. Research and development can contribute to that response in important ways. Some important themes emerge from analysis of this strategy. First, a dual-use approach, in which security objectives are furthered at the same time as other transportation goals, can encourage the implementation of security technologies and processes. Second, modeling could be used more to develop a better understanding of the scope of the security problem. Third, DOT can play an important role in developing and disseminating information about best practices that use existing technologies and processes, including low-technology alternatives. Finally, security should be considered as part of a broader picture, not a wholly new and different problem but one that is similar and closely connected to the transportation community's previous experience in responding to accidents, natural disasters, and hazardous materials. Table of Contents Front Matter Executive Summary 1 Introduction and Background 2 Assessing Vulnerability 3 Establishing a Research and Development Strategy 4 Applying the Methodology: Some Specific Research and Development Topics 5 A Vision for the Future References Appendix A: Background on Systems Theory Appendix B: The Likely Course of Development of Chemical and Biological Attacks Biographical Sketches of Committee Members