LIOn Delamination of Laminated Composites (a) Fiber-Reinforced Composites Considerable technological advances in the production of high-strength fibers (graphite, boron, etc.) have led to a wide use of light high-strength composite materials (graphite epoxy, boron-epoxy, etc.). It is expedient, to make thin walled composite rods, plates, and shells from such materials. Plates can be made by bonding a set of unidirectional thin fiber layers, Fig.l.l. Such plates are orthotropic, as a rule. A random short-fiber composite is shown in Fig. 1.2. Fiber-reinforced composites are widely used in thin-walled aircraft structures because of their specific high strength. For example, the graphite-epoxy composite is characterized by a unidirectional tensile strength of 1.4 GPa while the density is 1.6 Mg/rrt? . For comparison, we may take a steel (steel 4340) whose corresponding properties are identified by values like 1.2 GPa and 7.8 Mg/rrt? . 1. INTRODUCTION Figure 1.1 2 1.1. On Delamination of Laminated Composites Figure 1.2 3 1. INTRODUCTION It is characteristic for laminated plastic material to possess a fairly low bonding. Therefore, low-velocity impacts and defects in manufacturing lead to local delamination. (b) Linear Problems of Delamination Buckling Delamination can significantly reduce the compressive strength and stiffness of the laminate. Local delamination can be considered as a crack in the bond. Under buckling there appears a high interlaminate stress at the crack edge that leads to a spreading of the crack. Delamination growth can lead to structural instability."

The continuous and ever expanding development of high-temperature tech nology involves the use of high -temperature refractory materials and one of the most important classes of these is the oxides, i.e., compounds of elements with oxygen. Oxides are the oldest refractory compounds known in technology and this is connected with their high chemical stability and abundance in nature. In addition to the use of oxides as raw materials for metallurgical processes, the refractoriness, chemical stability, and magnetic and other technically important properties of oxides have been put to use since antiquity. At the present time the importance of oxides as bases of many materials for new technology is substantial and is growing rapidly with the development of processes for the direct conversion of various forms of energy into electrical energy, the development of nuclear technOlogy, electronics, semiconductor and dielectric technOlogy, and cosmic technology, where the refractoriness and chemical stability of oxides are used in combination with their specific physical properties. Oxides are the foundation of the so-called oxygen -containing or oxygen refractory materials, which are fundamental to high-temperature tech nology. Oxides are no less important as the bases of practically all structural ma terials and rocks. A number of oxides are involved in biological processes."

Most of the papers contained in this volume are based on pres entations made at the symposium on Catalytic Conversions of Synthesis Gas and Alcohols to Chemicals, which was held at the 17th Middle At lantic Regional Meeting of the American Chemical Society, April 6-8, 1983, in the setting of the Pocono Hershey Resort, White Haven, PA. I thank Dr. Ned D. Heindel, General Chairman, and Dr. Natalie Foster, Program Chairman, both of Lehigh University, for the invitation to organize the symposium. Financial support was received from Air Products and Chemicals, Inc. for the organization of the symposium, and acknowledgement is made to Air Products and Chemicals, Inc. and to the Donors of the Petroleum Research Fund, administered by the American Chemical Society, for partial support of the conduct of the symposium. The theme of this volume is the recent progress made in devel oping and understanding viable catalytic syntheses of chemicals di rectly from synthesis gas (CO + H2) or indirectly via alcohols. An aim of the symposium and of this volume is to provide a meaningful blend of applied and basic science and of the chemistry and engineer ing of processes that are, or hold promise to be, economically and industrially feasible. The topics demonstrate the increasing impor tance of synthesis gas as a versatile feedstock and emphasize the central role that alcohols, such as methanol, can playas chemical intermediates."

During the past few decades, much research has been reported on the formation of insoluble monomolecular films of lipids and biopolymers (synthetic polymers and proteins) on the surface of water or at the oil-water interface. This interest arises from the fact that monomolecular film studies have been found to provide much useful information on a molecular scale, information that is useful for understanding many industrial and biological phenomena in chemical, agricultural, pharmaceutical, medical, and food science applications. For instance, information obtained from lipid monolayer studies has been useful in determining the forces that are known to stabilize emulsions and biological cell membranes. The current texts on surface chemistry generally devote a single chapter to the characteristics of spread monolayers of lipids and biopolymers on liquids, and a researcher may have to review several hundred references to determine the procedures needed to investigate or analyze a particular phenomenon. Furthermore, there is an urgent need at this stage for a text that discusses the state of the art regarding the surface pheqomena exhibited by lipids and biopolymers, as they are relevant to a wide variety of surface and interfacial processes.

Micro Electro Mechanical Systems (MEMS) is already about a billion dollars a year industry and is growing rapidly. So far major emphasis has been placed on the fabrication processes for various devices. There are serious issues related to tribology, mechanics, surfacechemistry and materials science in the operationand manufacturingof many MEMS devices and these issues are preventing an even faster commercialization. Very little is understood about tribology and mechanical properties on micro- to nanoscales of the materials used in the construction of MEMS devices. The MEMS community needs to be exposed to the state-of-the-artoftribology and vice versa. Fundamental understanding of friction/stiction, wear and the role of surface contamination and environmental debris in micro devices is required. There are significantadhesion, friction and wear issues in manufacturing and actual use, facing the MEMS industry. Very little is understood about the tribology of bulk silicon and polysilicon films used in the construction ofthese microdevices. These issues are based on surface phenomenaand cannotbe scaled down linearly and these become increasingly important with the small size of the devices. Continuum theory breaks down in the analyses, e. g. in fluid flow of micro-scale devices. Mechanical properties ofpolysilicon and other films are not well characterized. Roughness optimization can help in tribological improvements. Monolayers of lubricants and other materials need to be developed for ultra-low friction and near zero wear. Hard coatings and ion implantation techniques hold promise.

This publication presents the proceedings of the NATO Advanced Research Workshop (ARW) on Computer Modelling of Electronic and Atomic Processes in Solids. This ARW was held at Szklarska Poreba, Wroclaw, Poland from May 20 -23, 1996, and brought together scientists from Canada, England, Germany, Israel, Latvia, Poland, Russia, Switzerland, United States, Ukraine and Uzbekistan. The NATO Advanced Research Workshops program is designed to increase collaboration and exchange of knowledge between the Eastern and Western scientific communities. This particular NATO ARW has already succeeded in that effort, and has spawned collaboration agreements and programs. One joint project in space materials has led to the launch of an experiment to the Russian MIR space station. This NATO ARW was also fortunate to be held concurrently with a workshop of the Wroclaw Technical University, in the same location, which focused on glass materials, thus providing for a larger scientific audience for a number of presentations of both groups. The primary emphasis of this ARW was on computer models, ranging from fundamental atomic, molecular and electronic structures and processes, through to macroscopic descriptions of materials in terms of their structure and properties. Various elements discussed in these proceedings include environmental effects, predictions of properties, correlations with experiments and material performance parameters. Applications to space and electronics were emphasized.

This volume contains the proceedings of the first International Conference on the Science of Hard Materials held in Moran, Wyoming, Aug. 23-28, 1981. The objective of the conference was to review and advance the state of knowledge of the basic physical and chemical properties of hard materials and show how these properties influence performance in a variety of applications. To this end, the 49 con tributed papers and the four keynote papers by Prof. Fischmeister and Drs. Hintermann, Exner and Almond, present an excellent overview of the state of the art in the "science" of hard materials. The contents of these proceedings also reflect the fact that hard metal technology is now well matured and several aspects of the behavior of these materials are well understood and firmly established. Structure-property relationships in this class of materials are currently well known. Pitfalls in some of the traditional test methods have been recognized and new test methods are being developed which discriminate between intrinsic material properties and flaw content and distribution. Application of fracture mechanics, al though a late corner to the hard materials area (as compared to other structural materials), is rapidly gaining acceptance and new fracture toughness test methods are being developed. Application of modern analysis and analytical techniques to these materials has begun and entirely new and unexpected information has been obtained. For a variety of reasons, "hard metals" have dominated the research and development scene of "hard materials.""

The characterization of materials and phenomena has historically been the principal limitation to the development in each area of science. Once what we are observing is well defined, a theoretical analysis rapidly follows. Modern theories of chemical bonding did not evolve until the methods of analytical chemistry had progressed to a point where the bulk stoichiometry of chemical compounds was firmly established. The great progress made during this century in understanding chemistry has followed directly from the development of an analytical chemistry based on the Dalton assumption of multiple proportions. It has only become apparent in recent years that the extension of our understanding of materials hinges on their non-stoichiometric nature. The world of non-Daltonian chemistry is very poorly understood at present because of our lack of ability to precisely characterize it. The emergence of materials science has only just occurred with our recognition of effects, which have been thought previously to be minor variations from ideality, as the principal phenomena controlling properties. The next step in the historical evolution of materials science must be the development of tools to characterize the often subtle phenomena which determine properties of materials. The various discussions of instrumental techniques presented in this book are excellent summaries for the state-of-the-art of materials characterization at this rather critical stage of materials science. The application of the tools described here, and those yet to be developed, holds the key to the development of this infant into a mature science.

Methods and Materials for Remote Sensing: Infrared Photo-Detectors, Radiometers and Arrays presents the basic principles and the guidelines for the design of IR and microwave radiometers intended for the detection of weak electromagnetic signals in a noisy background. Significant attention is paid in this book to the discussion of the origin of the noises and consideration of the physical factors limiting the sensitivity of photo sensors. The physico-chemical properties of narrow-band semiconductors, which are the basic photosensitive materials for the microwave and IR radiometry, are discussed. Also described are the methods for growing the single crystals, epitaxial films and arrays from solid solutions of these compounds for the application in photosensitive detectors. The main goal of Methods and Materials for Remote Sensing: Infrared Photo-Detectors, Radiometers and Arrays is to present the entire material from the unifying physical viewpoint, which will be helpful for the designers of photo-detecting devices, and professionals contributing in various areas of remote sensing.

The principal aim of this text is to encourage the development and application of numerical modelling techniques as an aid to achieving greater efficiency and optimization of metal-forming processes. The contents of this book have therefore been carefully planned to provide both an introduction to the fundamental theory of material deformation simulation, and also a comprehensive survey of the "state-of-the-art" of deformation modelling techniques and their application to specific and industrially relevant processes. To this end, leading international figures in the field of material deformation research have been invited to contribute chapters on subjects on which they are acknowledged experts. The information in this book has been arranged in four parts: Part I deals with plasticity theory, Part II with various numerical modelling techniques, Part III with specific process applications and material phenomena and Part IV with integrated computer systems. The objective of Part I is to establish the underlying theory of material deformation on which the following chapters can build. It begins with a chapter which reviews the basic theories of classical plasticity and describes their analytical representations. The second chapter moves on to look at the theory of deforming materials and shows how these expressions may be used in numerical techniques. The last two chapters of Part I provide a review of isotropic plasticity and anisotropic plasticity.

Physics of New Materials After the discoveries and applications of superconductors, new ceramics, amorphous and nano-materials, shape memory and other intelligent materials, physics became more and more important, comparable with chemistry, in the research and development of advanced materials. In this book, several important fields of physics-oriented new-materials research and physical means of analyses are selected and their fundamental principles and methods are described in a simple and understandable way. It is suitable as a textbook for university materials science courses.

This book originated out of the papers presented at the special symposium, "Electrochemistry in Transition-From the 20th to the 21st Century," scheduled by the Division of Colloid and Surface Science during the American Chemical Society meeting in Toronto. The symposium was in honor of Professor J. O'M. Bockris, who received the ACS award on "The Chemistry of Contemporary Technological Problems" (sponsored by Mobay Corporation) during this meeting and who also reached his 65th birthday in the same year. The symposium was of a multidisciplinary nature and encompassed the fields of theoretical and experimental elec trochemistry, surface science, spectroscopy, and electrochemical technology. The symposium also had an international flavor in that the participants represented several countries Australia, Belgium, Canada, Chile, England, Japan, Korea, the Netherlands, Poland, Switzer land, Venezuela, Yugoslavia, and the United States. The symposium was graciously sponsored by the ACS (Petroleum Research Fund and Division of Colloid and Surface Science), Alcan International, Dow Chemical Company, EG&G, Electrolyzer Corporation, Exxon, General Electric Company, IBM, Institute of Gas Technology, International Association of Hydrogen Energy, Johnson Matthey, Inc., Kerr-McGee Corporation, Medtronics, and Texas A&M University (Center for Electrochemical Systems and Hydrogen Research and the Hampton Robinson Fund). The "theme" of the papers presented at the symposium covered not only significant contributions made to electrochemistry in the twentieth century, but also "New Horizons in Electrochemistry" for the twenty-first century. Thus, the scientists who presented papers were invited to contribute chapters to this book, having the same titles as the symposium."

This treatise is a compendium of refereed papers based on invited talks presented at the American Chemical Society Symposium on Electrorheological (ER) Materials and Fluids. ER fluids were first investigated 50+ years ago. These fluids, which change rheology when placed in an electric field, were recognized, from the beginning, for allowing an extremely efficient interface between electrical control and mechanical devices. Critical problems, however, existed with the initial fluids, which prevented them from serious consideration for large-scale applications. While over time some of the critical problems have been solved and activity in ER technology has increased, commercial success has remained elusive. A recent Department of Energy report concluded that a primary reason for the failure to commercialize this promising technology is due to a lack in understanding the physics and chemistry of how the materials work. The goal of the symposium was to address the issue of understanding how ER materials work and how they can be used. One of the outcomes of the symposium, which we hope is conveyed in this book, is a feeling that if the mechanism of ER is to be fully understood and improved, expertise from diverse fields must be applied to the problem.

Nanophase Materials is the first and, as yet, the only comprehensive book published in this new and exciting area of materials science. It gives a broad overview of the revolutionary new field of nanophase materials; a view which spans the materials, physics, and chemistry research communities at a tutorial level that is suitable for advanced undergraduates, graduate students, postdoctoral researchers, and experts or would-be experts in the science of nanostructured materials. The articles are authored by many of the world's most prominent scientists in this field. The book covers the diverse methods for synthesizing nanophase materials, a variety of subsequent processing methodologies, what is known about the structures of these materials on various length scales from atomic to macroscopic, and the properties of these unique and novel materials. The materials properties covered are mechanical, electronic, optical, and magnetic and hence span a wide range of important new opportunities for technological applications.

A survey of the machinery and science of the nanometer scale. Its twenty-two contributing authors, drawn from many different disciplines including atomic physics, microelectronics, polymer chemistry, and biophysics, delineate the course of current research and articulate a vision for the development of the nanometer frontiers in electronics, mechanics, chemistry, magnetics, materials, and biology. They reveal a world thirty years hence where motors are smaller than the diameter of a human hair; where single-celled organisms are programmed to fabricate materials with nanometer precision; where single atoms are used for computation, and where quantum chaos is the norm. Aimed at the level of at least a junior- or senior- level undergraduate in biology, chemistry, physics, or engineering.

This book contains th Proceedings of the World Conference of the International Nuclear Target Development Society held in Boston, October 1-3, 1979. Approximately seventy participants and registrants from the following countries attended this Conference: Belgium, Canada, Denmark, United Kingdom, German Federal Republic, Israel, Japan, The Netherlands, Saudi Arabia, Switzerland, and the United States. The Conference was sponsored by the New England Nuclear Corporation. Conference Chairman in residence was Jozef Jaklovsky who was assisted by the invited Co-Chairman D. Riel of the State University of New York at Stony Brook. This publication incorporates the proceedings of an inter national conference concentrating on the general field of target preparation for use with particle accelerators. The publication includes additional contributions on target preparations by honorary members of this Society. For the first time in this field, an extensive bibliography collection (1936-June 1980) is included. Bibliography, subject index, author index, country index, and patent index have been organized by the editor. The biblioqraphy includes thin and thick particle accelerator targets and also preparation and use of targets in particle accelerators."

If an ion in a crystal is replaced by an impurity ion with a different charge, compensation for the charge difference must be accomplished. This is usually done by an intrinsic defect, i. e. a lattice vacancy or interstitial host ion, in such a way to balance the excess or deficit of charge. The introduction of cation vacan cies along with divalent cation impurities in alkali halides is a familiar example. If these crystals are carefully annealed, nearly all of the compensating defects migrate to the impurity ions to form impurity-defect complexes. It is the behavior of these complexes that are the principal concern in this paper. Almost invariably such complexes are dipolar in character, and when subjected to an electric or mechanical stress field, they will tend to realign to an orienta tion of lower energy provided the thermal activation is sufficiently great. If the complex consists of an impurity-vacancy couple, re orientation may occur either by the vacancy moving around the impu rity or by an exchange of positions of the partners. In general the activation energy for these two distinct reorientation paths is different. If the complex consists of an impurity-interstitial couple, interchange of positions is unlikely and reorientation is considered to occur exclusively by the motion of the interstitial around the vacancy."

This volume contains a series of papers originally presented at the Symposium on Polymer Gels organized and sponsored by the Research Group on Polymer Gels, The Society of Polymer Science of Japan and co-sponsored by the Science and Technology Agency (ST A) and MIT , Japan. The Symposium took place at Tsukuba Science City on 18th and 19th September, 1989. Recognized experts in their fields were invited to speak and there was a strong attendance from government, academic and industrial research centers. The purpose of the Symposium was to review the state of the art and to present and discuss recent progress in the understanding of the behavioral properties of polymer gels and their application to biomedical, environmental and robotic fields. Most of the papers and related discussions concentrated on the swelling behavior of hydrogels and chemomechanical systems, both artificial and naturally occurring, in which external stimuli of a physical or chemical nature control energy transformation or signal transduction. The recent great interest in chemomechanical systems based on polymer gels has stimulated considerable effort towards the development of new sensors and actuators, controllable membrane separation processes, and delivery systems in which the functions of sensing, processing and actuation are all built into the polymeric network device. Artificial chemomechanical systems, through the use of environmentally sensitive polymer gels, are emerging as interesting materials for mimicking basic processes previously only confined to the biological world, and commercially viable applications are also foreseen in the not-too-distant future

This collection on "Mechanics of Generalized Continua - from Micromechanical Basics to Engineering Applications" brings together leading scientists in this field from France, Russian Federation, and Germany. The attention in this publication is be focussed on the most recent research items, i.e., - new models, - application of well-known models to new problems, - micro-macro aspects, - computational effort, - possibilities to identify the constitutive equations, and - old problems with incorrect or non-satisfying solutions based on the classical continua assumptions.

This text provides students as well as practitioners with a comprehensive introduction to the field of scanning electron microscopy (SEM) and X-ray microanalysis. The authors emphasize the practical aspects of the techniques described. Topics discussed include user-controlled functions of scanning electron microscopes and x-ray spectrometers and the use of x-rays for qualitative and quantitative analysis. Separate chapters cover SEM sample preparation methods for hard materials, polymers, and biological specimens. In addition techniques for the elimination of charging in non-conducting specimens are detailed.

Boron has all the best tunes. That may well be the first impression of the Group 13 elements. The chemical literature fosters the impression not only in the primary journals, but also in asteady outflowofbooks focussing more or less closely on boron and its compounds. The same preoccupation with boron is apparent in the coverage received by the Group 13 elements in the comprehensive and regularly updated volume of the Gmelin Handbook. Yet such an imbalance cannot be explained by any inherent lack ofvariety, interest or consequence in the 'heavier elements. Aluminium is the most abundant metal in the earth's crust; in the industrialised world the metal is second only to iron in its usage, and its compounds can justifiably be said to touch our lives daily - to the potential detriment of those and other lives, some would argue. From being chemical curios, gallium and indium have now gained considerably prominence as sources of compound semiconductors like gallium arsenide and indium antimonide. Nor is there any want ofincident in the chemistriesofthe heavier Group 13 elements. In their redox, coordination and structural properties, there is to be found music indeed, notable not always for its harmony but invariably for its richness and variety. Thisbook seeks to redress the balance with a definitive, wide-rangingand up-to-date review of the chemistry of the Group 13 metals aluminium, gallium, indium and thallium.

There are two motives for studying materials processing in centrifuges. First, such research improves our understanding of the influence of acceleration and convection on materials processing. Second, there are commercial opportunities for production of unique and improved materials that cannot be prepared under normal earth conditions or in space. Through a combination of experiments and theory, we are gaining an understanding of centrifugation on phenomena of importance to materials processing. We find that it is necessary to consider not only acceleration, but also the Corio lis effect and the variation of acceleration with position. As one consequence, the vigor of buoyancy-driven convection is sometimes increased by centrifugation and sometimes decreased. Similarly, the tendency of the convection to become unstable or oscillatory may either be increased or decreased by centrifugation. On the other hand, the observed effects of centrifugation on product quality have largely gone unexplained. This volume constitutes the proceedings of The Second International Workshop on Materials Processing at High Gravity, hosted by Clarkson University in June of 1993. The concept for a workshop on materials processing in centrifuges was born at a series of informal meetings held in Paris in 1990. The First International Workshop on Materials Processing at High Gravity was held in May of 1991 in Dubna, USSR, on the banks of the Volga River. The proceedings of this workshop was published in 1992 as a special issue of the Journal of Crystal Growth.

This book willbcof value to anyone who wishes to consider the use of SQUID-based magnetic sensing for anyone of a number of practical applications. The focus here is to examine in detail how SQUID technology is used and how. the results of the measurements obtained can be interpreted to provide useful information in a variety of real-world applications. The concentration is on those areas that have received the most attention, namely bioma etism and nondestructive evaluation, but. the topics chosen include as well, geophysics, underwater ordnance detection, accelerometry and a few somewhat more exotic applications. To provide a reasonable perspective. an attempt has been made to consider competing technologies for most applications, and in some cases to consider how SQUID-based technology may be integrated with other technologies to provide an optimum total-system configuration. It is also the intention of the editor, that this book will be of major value to those scientists and engineers who will be required to build both the essential components and complete cryogenic SQUID systems which will be utilized in the various applications presented. Thus, there is a comprehensive review of the principles of SQUID operation, and a detailed exposition on the fabrication of high-temperature-superconducting (HTS) SQUIDs. Although the market is currently dominated by low-temperature superconducting (L TS) SQUIDs, it is reasonably certain that in the near future HTS SQUIDs will take over in most situations."

These volumes, 3 and 4, of Fracture Mechanics of Ceramics con stitute the proceedings of an international symposium on the frac ture mechanics of ceramics held at the Pennsylvania State Univer sity, University Park, PA on July 27, 28, and 29, 1977. Volumes 1 and 2 were published previously as the proceedings of a sympo sium of the same name held July 11, 12, and 13, 1973, also at Penn State. All four volumes published to date concentrate on the fracture aspects of the mechanical behavior of brittle'ceramics in terms of the characteristics of cracks. The program chairmen gratefully acknowledge the financial as sistance for the symposium provided by the Office of Naval Re search, the Energy Research and Development Administration, and the Army Research Office. Without their support the quality and mag nitude of this conference simply would not have been possible. Numerous individuals contributedto the success of the con ference, but unfortunately they cannot all be listed here. However the program chairmen would especially like to recognize the contri butions of Penn State Conference Coordinator, Mr. Ronald Avillion, whose expertise in planning and organization was indispensable; Dr. Fred R. Matson for his interesting after dinner speech; and Drs. A. M. Diness, J. C. Hurt, and D. W. Readey for their en couragement and valuable suggestions regarding the program. Finally, we wish to also thank our joint secretaries for the patience and help in bringing these proceedings to press."

From 5 to 15 August 1984, a group of 79 physicists from 61 laboratories in 26 countries met in Erice for the 22nd Course of the International School of Subnuclear Physics. The countries represented were Austria, Belgium, Brazil, Bulgaria, Canada, People's Republic of China, Denmark, the Federal Republic of Germany, France, Greece, Hungary, Iran, Israel, Italy, Japan, Korea, Malaysia, Mexico, the Netherlands, Pakistan, Poland, Sweden, Switzerland, Turkey, the United Kingdom, the United States of America. The School was sponsored by the Italian Ministry of Public Education (MPI), the Italian Ministry of Scientific and Technologi cal Research (MRST), the Regional Sicilian Government (ERS), and the Weizmann Institute of Science. The programme of the School was devoted to a review of the most significant results in theoretical and experimental research work on the interactions between what we believe today are the point like constituents of the world: quarks and leptons. It should however not be forgotten that many problems are still to be understood: especially in the forefront of the correla tion between quarks and leptons. This game started in 1966 with the proposal for "leptonic quarks" and went on with "preons" and "rishons" just to quote the most famous attempts to unify these two worlds."