Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report. Volume 6

Acoustic Transduction - Materials and Devices, Period 31 July 1996 to 31 December 1997, Annual Report. Volume 6
Author:
Publisher:
Total Pages: 0
Release: 1998
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ISBN:

In Material Studies, undoubtedly major breakthroughs have occurred in the ultra- high strain relaxor ferroelectric systems. Earlier reports of unusual piezoelectric activity in single crystal perovskite relaxors have been amply confirmed in the lead zinc niobate: lead titanate, and lead magnesium niobate : lead titanate systems for compositions of rhombohedral symmetry close to the Morphotropic Phase Boundary (MPB) in these solid solutions. Analysis of the unique properties of 001 field poled rhombohedral ferroelectric crystals suggests new intrinsic mechanisms for high strain and carries the first hints of how to move from lead based compositions. A major discovery of comparable importance is a new mode of processing to convert PVDF:TrFE copolymer piezoelectric into a relaxor ferroelectric in which electrostrictive strains of 4% have been demonstrated at high fields. Both single crystal and polymer relaxors appear to offer energy densities almost order of magnitude larger than in earlier polycrystal ceramic actuators. Transducer Studies have continued to exploit the excellent sensitivity and remarkable versatility of the cymbal type flextensional element. Initial studies of a small cymbal arrays show excellent promise in both send and receive modes, and larger arrays are now under construction for tests at ARL. New studies in constrained layer vibration damping and in flow noise reduction are yielding exciting new results. In Actuator Studies, an important advance in piezoelectric generated noise control now permits wider use of acoustic emission as a reliability diagnostic technique. Joint studies with NRL, Washington have developed a completely new d15 driven torsional actuator and the CAV program element has designed an exciting high strain high force inchworm. Finite element analysis continues to be an important tool for understanding the more complex composite structures and their beam forming capability in water.

Piezoelectric Energy Harvesting

Piezoelectric Energy Harvesting
Author: Alper Erturk
Publisher: John Wiley & Sons
Total Pages: 377
Release: 2011-04-04
Genre: Technology & Engineering
ISBN: 1119991358

The transformation of vibrations into electric energy through the use of piezoelectric devices is an exciting and rapidly developing area of research with a widening range of applications constantly materialising. With Piezoelectric Energy Harvesting, world-leading researchers provide a timely and comprehensive coverage of the electromechanical modelling and applications of piezoelectric energy harvesters. They present principal modelling approaches, synthesizing fundamental material related to mechanical, aerospace, civil, electrical and materials engineering disciplines for vibration-based energy harvesting using piezoelectric transduction. Piezoelectric Energy Harvesting provides the first comprehensive treatment of distributed-parameter electromechanical modelling for piezoelectric energy harvesting with extensive case studies including experimental validations, and is the first book to address modelling of various forms of excitation in piezoelectric energy harvesting, ranging from airflow excitation to moving loads, thus ensuring its relevance to engineers in fields as disparate as aerospace engineering and civil engineering. Coverage includes: Analytical and approximate analytical distributed-parameter electromechanical models with illustrative theoretical case studies as well as extensive experimental validations Several problems of piezoelectric energy harvesting ranging from simple harmonic excitation to random vibrations Details of introducing and modelling piezoelectric coupling for various problems Modelling and exploiting nonlinear dynamics for performance enhancement, supported with experimental verifications Applications ranging from moving load excitation of slender bridges to airflow excitation of aeroelastic sections A review of standard nonlinear energy harvesting circuits with modelling aspects.

Converging Technologies for Improving Human Performance

Converging Technologies for Improving Human Performance
Author: William Sims Bainbridge
Publisher: Springer
Total Pages: 468
Release: 2014-03-14
Genre: Technology & Engineering
ISBN: 9789401703604

M. C. Roco and W.S. Bainbridge In the early decades of the 21st century, concentrated efforts can unify science based on the unity of nature, thereby advancing the combination of nanotechnology, biotechnology, information technology, and new technologies based in cognitive science. With proper attention to ethical issues and societal needs, converging in human abilities, societal technologies could achieve a tremendous improvement outcomes, the nation's productivity, and the quality of life. This is a broad, cross cutting, emerging and timely opportunity of interest to individuals, society and humanity in the long term. The phrase "convergent technologies" refers to the synergistic combination of four major "NBIC" (nano-bio-info-cogno) provinces of science and technology, each of which is currently progressing at a rapid rate: (a) nanoscience and nanotechnology; (b) biotechnology and biomedicine, including genetic engineering; (c) information technology, including advanced computing and communications; (d) cognitive science, including cognitive neuroscience. Timely and Broad Opportunity. Convergence of diverse technologies is based on material unity at the nanoscale and on technology integration from that scale.

Alternatives for Landmine Detection

Alternatives for Landmine Detection
Author: Jacqueline MacDonald Gibson
Publisher: Rand Corporation
Total Pages: 336
Release: 2003
Genre: Political Science
ISBN: 9780833033017

At the rate that government and nongovernmental organizations are clearing existing landmines, it will take 450-500 years to rid the world of them. Concerned about the slow pace of demining, the Office of Science and Technology asked RAND to assess potential innovative technologies being explored and to project what funding would be required to foster the development of the more promising ones. The authors of this report suggest that the federal government undertake a research and development effort to develop a multisensor mine detection system over the next five to eight years.

Feedback Systems

Feedback Systems
Author: Karl Johan Åström
Publisher: Princeton University Press
Total Pages:
Release: 2021-02-02
Genre: Technology & Engineering
ISBN: 069121347X

The essential introduction to the principles and applications of feedback systems—now fully revised and expanded This textbook covers the mathematics needed to model, analyze, and design feedback systems. Now more user-friendly than ever, this revised and expanded edition of Feedback Systems is a one-volume resource for students and researchers in mathematics and engineering. It has applications across a range of disciplines that utilize feedback in physical, biological, information, and economic systems. Karl Åström and Richard Murray use techniques from physics, computer science, and operations research to introduce control-oriented modeling. They begin with state space tools for analysis and design, including stability of solutions, Lyapunov functions, reachability, state feedback observability, and estimators. The matrix exponential plays a central role in the analysis of linear control systems, allowing a concise development of many of the key concepts for this class of models. Åström and Murray then develop and explain tools in the frequency domain, including transfer functions, Nyquist analysis, PID control, frequency domain design, and robustness. Features a new chapter on design principles and tools, illustrating the types of problems that can be solved using feedback Includes a new chapter on fundamental limits and new material on the Routh-Hurwitz criterion and root locus plots Provides exercises at the end of every chapter Comes with an electronic solutions manual An ideal textbook for undergraduate and graduate students Indispensable for researchers seeking a self-contained resource on control theory

Diagnostic Radiology Physics

Diagnostic Radiology Physics
Author: International Atomic Energy Agency
Publisher:
Total Pages: 0
Release: 2014
Genre: Medical
ISBN: 9789201310101

This publication is aimed at students and teachers involved in programmes that train medical physicists for work in diagnostic radiology. It provides a comprehensive overview of the basic medical physics knowledge required in the form of a syllabus for the practice of modern diagnostic radiology. This makes it particularly useful for graduate students and residents in medical physics programmes. The material presented in the publication has been endorsed by the major international organizations and is the foundation for academic and clinical courses in both diagnostic radiology physics and in emerging areas such as imaging in radiotherapy.

Autonomous Horizons

Autonomous Horizons
Author: Greg Zacharias
Publisher: Independently Published
Total Pages: 420
Release: 2019-04-05
Genre:
ISBN: 9781092834346

Dr. Greg Zacharias, former Chief Scientist of the United States Air Force (2015-18), explores next steps in autonomous systems (AS) development, fielding, and training. Rapid advances in AS development and artificial intelligence (AI) research will change how we think about machines, whether they are individual vehicle platforms or networked enterprises. The payoff will be considerable, affording the US military significant protection for aviators, greater effectiveness in employment, and unlimited opportunities for novel and disruptive concepts of operations. Autonomous Horizons: The Way Forward identifies issues and makes recommendations for the Air Force to take full advantage of this transformational technology.

Chemical and Biochemical Applications

Chemical and Biochemical Applications
Author: Pierre Laszlo
Publisher: Elsevier
Total Pages: 317
Release: 2012-12-02
Genre: Science
ISBN: 0323156347

NMR of Newly Accessible Nuclei, Volume 1: Chemical and Biochemical Applications is a 10-chapter text that explores the properties, advantages, developments, and chemical and biochemical applications of NMR technique. This book describes first the operation of an NMR spectrometer under its two aspects, namely, the instrumental and the computational aspects. The next chapters are devoted to some of the most important pulse sequences. The discussion then shifts to the various factors determining the position of the observed absorption and those responsible for the various relaxation processes. The last chapters deal with the specific applications of NMR, including in cation salvation, calcium-binding proteins, polyelectrolyte systems, halogens, and antibiotic ionophores. This book is of value to inorganic and analytical chemists, and biophysicists.