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."

The Army Materials and Mechanics Research Center has conducted the Saga more Army Materials Research Conferences, in cooperation with the Metallurgi cal Research Laboratories of the Department of Chemical Engineering and Metallurgy of Syracuse University, since 1954. The purpose of the conferences has been to gather together scientists and engineers from academic institutions, industry, and government who are uniquely qualified to explore in depth a sub ject of importance to the Army, the Department of Defense and the scientific community. Grain size and its control is a major factor governing the behavior of materi als. Knowledge that one can obtain grain sizes in the 10 micron down to sub micron range has established the basis for a new technology. This volume, Ultrafine-Grain Ceramics, addresses itself to the broad areas of: realization of fine-grain ceramics; preparation of ultrafine particle size materials; characterization of ultrafine particles and ultrafine-grain ceramics; processing and behavior of ultra fine-grain ceramics. The technical advice provided by Dr. S. K. Dutta of the Army Materials and Mechanics Research Center during the editing of this book is acknowledged. The continued active interest and support of these conferences by Dr. E. Scala, Director, Lt. Col. Joseph B. Mason, Commanding Officer, and J. F. Sullivan, Deputy Technical Director, of the Army Materials and Mechanics Re search Center is appreciated.

Carbon fibre reinforced carbon composites form a very specialized group of materials. They may be considered as a development of the family of carbon fibre reinforced polymer composites which are becoming ever more prevalent in modern engineering. Since the early 1960s a large number of so-called 'advanced materials' have appeared on the scene. Carbon arbon is arguably the most successful of all these products finding many and varied applications. In the field of Formula 1 motor racing for example, the present levels of performance simply could not be achieved without the use of carbon-carbon brakes and clutches. Despite the materials' obvious assets, they have not, and will not, reach their full potential until their inherent problems of excessive production costs and oxidation resistance have been addressed properly. In this respect the 'carbon-carbon story', of much potential but only limited success, serves as a lesson to all those involved in materials research, development and application. In writing this book I have tried to set up a logical progression of what the materials are, how they are made, what their assets and deficiencies are, what they are used for and to what extent they are commercially exploited. Each specialized chapter may be considered in isolation or as part of a sequence, whereas the final chapter provides a summary of the principal concepts as well as a basic review of the economic situation past, present and, hopefully, future.

Most industrial and natural materials exhibit a macroscopic behaviour which results from the existence of microscale inhomogeneities. The influence of such inhomogeneities is commonly modelled using probabilistic methods. Most of the approaches to the evaluation of the safety of structures according to probabilistic criteria are somewhat scattered, however, and it is time to present such material in a coherent and up-to-date form. Probabilities and Materials undertakes this task, and also defines the great tasks that must be tackled in coming years. For engineers and researchers dealing with materials, geotechnics, solid mechanics, soil mechanics, statistics and stochastic processes. The expository nature of the book means that no prior knowledge of statistics or probability is required of the reader. The book can thus serve as an excellent introduction to the nature of applied statistics and stochastic modelling.

Limp materials are used in many economically impo~tant industries such as garment manufacture, shoe manufacture, aerospace (composites) and automobiles (seats and trim). The use of sensors is essential for reliable robotic handling of these materials, which are often based on naturally occurring substances such as cotton and leather. The materials are limp and have non-homogeneous mechanical properties which are often impossible to predict accurately. The applications are very demanding for vision and tactile sensing and signal processing, adaptive control systems, planning and systems integration. This book comprises the collection of papers presented at the NATO Advanced Research Workshop on 'Sensory Robotics for the Handling of Limp Materials', held in October 1988 at II Ciocco, Tuscany, Italy. The aim of the workshop was to examine the state of the art and determine what research is needed to provide the theoretical and technological tools for the successful application of sensory robotics to the handling of limp materials. The meeting also acted as the first-ever forum for the interchange of knowledge between applications-driven researchers and those researching into the provision of fundamental tools. The participants were drawn from academia (20), industry (5), and other non-university research organisations (5).

The field of narrow-gap II-VI materials is dominated by lhe compound mercury cadmium telluride, MCT or Hg1_ .. Cd .. Te. By varying the x value, material can be made to cover all the important infrared (lR) ranges of interest. It is probably true to say that MCT is the third most studied semiconductor after silicon and gallium arsenide. As current epitaxial layers of MCT are mainly grown on bulk CdTe family substrates these materials are included in this book, although strictly, of course, they are not 'narrow-gap'. This book is intended for readers who are either new to the field or are experienced workers in the field who need a comprehensive and up to date view of this rapidly expanding area. To satisfy the needs of the frrst group each chapter discusses the principles underlying each topic and some of the historical background before bringing the reader the most recent information available. For those currently in the field the book can be used as a collection of useful data, as a guide to the literature and as an overview of topics covering the wide range of work areas."

Proceedings of a Summer School at Michigan State University held in East Lansing, Michigan, July 17-19, 1994

All significant studies agree that aqueous corrosion continues to cost nations dearly in almost every area of technological endeavour. Over the past ten years, microcomputers have facilitated an explosion in the power of modelling as a technique in science and engineering. In corrosion they have enabled better understanding of polarization curves, they have transformed the scope of electrochemical impedance measurements and they have placed a large range of electrochemistry at the fingertips of the corrosion scientist. This book focuses on the models, rather than the computing, which have been made possible during the past decade. Aimed at all those with an interest in corrosion and its control, the book draws together the range of new modelling strands, suggests new avenues of approach and generates further momentum for improvements to corrosion management, whether by increased understanding of atomistic processes or by control of large plant.

The first edition of this book (1958) described an analytical situation which had existed for a number of years for maintaining quality control on vulcanizates of natural rubber although the situation had recently been disturbed by the introduction of a range of synthetic rubbers which required identification and quantitative estimation. For the former purpose 'wet' chemistry, based on various imperfectly understood organic reactions, was pressed into service. Alongside this was the first introduction of instrumental analysis, using the infrared spectra of either the polymers or, more usually, their pyrolytic products to 'fingerprint' the material. The identification of a range of organic accelerators, antioxidants and their derivatives which had been intro duced during the 1920s and 30s was, in the first edition, dealt with by a combination of column chromatography and infrared spectroscopy or by paper chromatography. Quantitative procedures were, however, still classical in the tradition of gravimetric or volumetric assays with an initially weighed sample yielding, after chemical manipulation, a carefully precipitated, dried and weighed end product, or a solution of known composition whose weight or titre, as a percentage of the initial sample, quantified the function being determined. The second edition of this work (1968) consolidated the newer techni ques which had been introduced in the first without adding to them although, in other applications of analytical chemistry, instrumental analysis had already brought about a transformation in laboratory practice."

Engineering tasks are supposed to achieve defined goals under certain project constraints. Example goals of software engineering tasks include achieving a certain functionality together with some level of reliability or performance. Example constraints of software engineering tasks include budget and time limitations or experience limitations of the developers at hand. Planning of an engineering project requires the selection of techniques, methods and tools suited to achieve stated goals under given project constraints. This assumes sufficient knowledge regarding the process-product relationships (or effects) of candidate techniques, methods and tools. Planning of software projects suffers greatly from lack of knowledge regarding the process-product relationships of candidate techniques, methods and tools. Especially in the area of testing a project planner is confronted with an abundance of testing techniques, but very little knowledge regarding their effects under varying project conditions. This book offers a novel approach to addressing this problem: First, based on a comprehensive initial characterization scheme (see chapter 7) an overview of existing testing techniques and their effects under varying conditions is provided to guide the selection of testing approaches. Second, the optimisation of this knowledge base is suggested based on experience from experts, real projects and scientific experiments (chapters 8, 9, and 10). This book is of equal interest to practitioners, researchers and students. Practitioners interested in identifying ways to organize their company-specific knowledge about testing could start with the schema provided in this book, and optimise it further by applying similar strategies as offered in chapters 8 and 9.

The IUTAM-Symposium on "Finite Inelastic Deformations - Theory and Applications" took place from August 19 to 23, 1991, at the University of Hannover, Germany, with 75 participants from 14 countries. Scope of the symposium was a fundamental treatment of new developments in plasticity and visco-plasticity at finite strains. This covered the phenomenological material theory based on continuum mechanics as well as the treatment of microstructural phenomena detected by precise experimental datas. In a restricted number, lectures on new experi mental facilities for measuring finite strains were also implemented into the symposium. Another important topic of the symposium was the treatment of reliable and effective computational methods for solving engineering problems with finite inelastic strains. Wi thin this context it was an essential feature that theory, numerical and computational analysis were be seen in an integrated way. In total 9 sessions with 37 lectures, many of them given by well known keynote-lecturers, and a poster session with 10 contributions met fully our expectations of a high ranking up-to-date forum for the interaction of four topics, namely the physical and mathematical modelling of finite strain inelastic deformations including localizations and damage as well as the achievements in the numerical analysis and implementation and the solution of complicated engineering systems. Special and important features were reliable material datas from macroscopic and microscopic tests as well as test results of complex engineering problems, like deep drawing and extrusion."

There are numerous technological materials - such as metals, polymers, ceramics, concrete, and many others - that vary in properties and serviceability. However, the almost universal common theme to most real materials is that their properties depend on the scale at which the analysis or observation takes place and at each scale "probabilities" play an important role. Here the word "probabilities" is used in a wider than the classical sense. In order to increase the efficiency and serviceability of these materials, researchers from NATO, CP and other countries were brought together to exchange knowledge and develop avenues for progress and applications in the st 21 century. The workshop began by reviewing progress in the subject area over the past few years and by identifying key questions that remain open. One point was how to observe/measure material properties at different scales and whether a probabilistic approach, at each scale, was always applicable and advantageous. The wide range of materials, from wood to advanced metals and from concrete to complex advanced composites, and the diversity of applications, e.g. fatigue, fracture, deformation, etc., were recognized as "obstacles" in identifying a "universal" approach.

In view of its extreme complexity the mathematical description of the mechanical behaviour of granular materials is an extremely difficult task. Today many different models compete with each other. However, the complexity of the models hinders their comparison, and the potential users are confused and, often, disencouraged. This book is expected to serve as a milestone in the present situation, to evaluate the present methodes, to clear up the situation, to focus and encourage for further research activities.

This book represents the proceedings of the second inter disciplinary conference on materials characterization held from July 30 through August 3, 1984 at the New York State College of Ceramics at Alfred University. The conference was the 20th in the University Series on Ceramic Science, instituted in 1964 by Alfred University, the University of California at Berkeley, North Carolina State University and Notre Dame University. Volume I of the proceedings of the first conference using this interdisciplinary approach to materials characterization was published as "Advances in Materials Characterization," edited by D. R. Rossington, R. A. Condrate and R. L. Snyder, and was listed as volume 15 of the Materials Science Research series of Plenum Press (New York, 1983). The purpose of bringing together scientists from a wide range of disciplines to present and discuss the latest developments in their fields is to promote cross fertilization. The first conference of this type and its resulting volume of proceedings stimulated a significant dialogue between disciplines concerning the characterization of materials, therefore indicating a need for a continuing series of such conferences. Characterization lies at the core of materials science."

The beneficial impact of the European communities involvement in scientific research and technology is wide-ranging and pervasive. There are high hopes of major advances in scientific knowledge and technological processes, while the emergence of a genuine tradition of collaborative research holds out great and continuing promise for the future. Close, frequent and long-term cooperation between universities, research centres and industry is already generating new synergies, forging a truly European scientific community. Many of tomorrows industrial developments, destined to be determinant for our economic success and prosperity, will spring from this research. The Concerted European Action on Magnets - CEAM - project is a prime example of collaborative research and development. Financed from the Communities STIMULATION action and implemented with the help of EURAM, the advanced materials programme, CEAM will bestow great benefits on European industrial competitiveness, providing a channel for high quality basic research to find its way into commercial products. This remarkable cooperative enterprise brought t gether 58 laboratories and more than 120 scientists and englneers in a sustained thirty month effort. It spanned every aspect of new iron-based high performance magnets from theoretical modelling of their intrinsic magnetic properties to the design and construction of novel electrical devices and machines. Besides adding a new European dimension to advanced magnetic technology, CEAM also ensured that a whole new generation of young researchers and technicians have been trained in applied magnetism.

Materials Chemistry is rapidly emerging as a key component of contemporary science. The strongly interdisciplinary nature of the field requires input from all branches of chemistry, from crystallography, from solid state physics and from computational and theoretical techniques. This book aims to give a coherent survey of the field by considering all the major aspects of the current study of the chemistry of materials. Early chapters emphasise basic principles and techniques. Strong emphasis is given to new techniques and technologies, for example, the opportunities opened up by new synchrotron sources in crystallography, and new computational techniques in simulation studies of complex materials. Characterisation techniques including crystallographic, microscopic and spectroscopic techniques are then described. Key contemporary themes such as atomic transport, reactivity and catalysis are reviewed. Later chapters focus on specific dasses of material, induding solid state ionics, ceramics (induding giant magneto-resistance and high temperature superconducting solids), microporous and molecular materials. We hope that the book provides a snapshot of the scientific and technological challenges in this fast developing field. The editors would like to thank the NATO Scientific Affairs Division for funding the School on which this volume is basedj financial contribution from Johnson Matthey Technology Centre is also gratefully acknowledged. We are most grateful to Mrs Jean Conisbee for all her efforts in preparing the manuscript.

The first International Conference on Ageing Studies and Lifetime Extension of Materials was held on th July 12-14 , 1999 at St. Catherine's College, Oxford, United Kingdom. Over 230 delegates attended during the three days and heard nearly ninety papers, together with over thirty poster presentations. Sixteen of these papers were keynotes from invited speakers eminent in their field of research. The proceedings were organised into six separate sessions: observation and understanding of real-time and accelerated ageing; experimental techniques; modelling and theoretical studies; lifetime prediction and validation; lifetime extension; and material design for ageing. In doing this, it was hoped to cover most issues of scientific concern inthefield ofmaterials ageing. One important aspect was that the conference did not concentrateon any particular group or type ofmaterial; rather the aim was to attract contributions from workers engaged in ageing studies with as wide a range of materials as possible. In this way, it was hoped that delegates could interactwith and learnfrom those whom they perhapswould not normally come across and that metallurgists could learn from polymer scientists, ceramicists could talk to modellers, and so on, in this important field. A read through the diverse papers contained within these proceedings will confirm that this aim was happily satisfied. Why hold such a meeting? In the modem world, engineered systems are expected to last longer.