Materialeprøvning

This volume of Modern Aspects of Electrochemistry contains six chapters. The first four chapters are about phenomena of interest at the microscopic level and the last two are on phenomena at the macroscopic level. In the first chapter, Uosaki and Kita review various theoretical models that have been presented to describe the phenomena that occur at an electrolyte/ semiconductor interface under illumination. In the second chapter, Orazem and Newman discuss the same phenomena from a different point of view. In Chapter 3, Bogus­ lavsky presents state-of-the-art considerations of transmembrane potentials and other aspects of active transport in biological systems. Next, Burke and Lyons present a survey of both the theoretical and the experimental work that has been done on hydrous oxide films on several metals. The last two chapters cover the topics of the production of chlorine and caustic and the phenomena of electrolytic gas evol­ ution. In Chapter 5, Hine et al. describe the engineering aspects of the three processes used in the chi or-alkali industry, and in Chapter 6, Sides reviews the macroscopic phenomena of nucleation, growth, and detachment of bubbles, and the effect of bubbles on the conduc­ tivity of and mass transfer in electrolytes.

Through his voluminous and in?uential writings, editorial activities, organi- tional leadership, intellectual acumen, and strong sense of history, Clifford - brose Truesdell III (1919¿2000) was the main architect for the renaissance of - tional continuum mechanics since the middle of the twentieth century. The present collection of 42 essays and research papers pays tribute to this man of mathematics, science, and natural philosophy as well as to his legacy. The ?rst ?ve essays by B. D. Coleman, E. Giusti, W. Noll, J. Serrin, and D. Speiser were texts of addresses given by their authors at the Meeting in memory of Clifford Truesdell, which was held in Pisa in November 2000. In these essays the reader will ?nd personal reminiscences of Clifford Truesdell the man and of some of his activities as scientist, author, editor, historian of exact sciences, and principal founding member of the Society for Natural Philosophy. The bulk of the collection comprises 37 research papers which bear witness to the Truesdellian legacy. These papers cover a wide range of topics; what ties them together is the rational spirit. Clifford Truesdell, in his address upon receipt of a Birkhoff Prize in 1978, put the essence of modern continuum mechanics succinctly as ¿conceptual analysis, analysis not in the sense of the technical term but in the root meaning: logical criticism, dissection, and creative scrutiny.

The past five years have witnessed some dramatic developments in the general area of ferroelectric thin films materials and devices. Ferroelectrics are not new materials by any stretch ofimagination. Indeed, they have been known since the early partofthis century and popular ferroelectric materials such as Barium Titanate have been in use since the second world war. In the late sixties and seventies, a considerable amountofresearch and development effort was made to create a solid state nonvolatile memory using ferroelectrics in a vary simple matrix-addressed scheme. These attempts failed primarily due to problems associated with either the materials ordue to device architectures. The early eighties saw the advent of new materials processing approaches, such as sol-gel processing, that enabled researchers to fabricate sub-micron thin films of ferroelectric materials on a silicon substrate. These pioneering developments signaled the onsetofa revival in the areaofferroelectric thin films, especially ferroelectric nonvolatile memories. Research and development effort in ferroelectric materials and devices has now hit a feverish pitch, Many university laboratories, national laboratories and advanced R&D laboratories oflarge IC manufacturers are deeply involved in the pursuit of ferroelectric device technologies. Many companies worldwide are investing considerable manpower and resources into ferroelectric technologies. Some have already announced products ranging from embedded memories in micro- controllers, low density stand-alone memories, microwave circuit elements, andrf identification tags. There is now considerable optimism that ferroelectric devices andproducts will occupy a significant market-share in the new millennium.

Recently a new sphere in materials science* has formed which subject is structure and properties of electret materials used in engineering, medicine, biotechnology and other branches. It is characterized by specific methods of experimental investigations based on recording charge transfer, polarization and depolarization of dielectrics and involves original techniques and physico-mathematical aids where notions that exist at the interface of several natural and technical sciences are concentrated. It embraces a vast area of applications mainly in engineering, instrument- making, electronics, medical technique, biotechnology, and etc., has a specialized technological base for electric polarization of dielectrics composed of uncommon technological methods, equipment and instrumentation. Apparently, future fundamental investigations in the domain of electret materials science are to be developed at the interface of computer of dielectrics. Elaboration of a simulation, physics and physical chemistry model for electric polarization of solid media with uneven charge density distribution, complicated by surface phenomena, outer electromagnetic, heat, chemical and other effects, presents a grave methodological problem. The simulation of structures in which polarization follows diffusion mechanism of chemically active molecules or their fragments, and the development of calculation methods for polarized charge relaxation and regularities of dielectric nonlinear properties, are the most urgent objectives of current research. Success in bioelectret effect studies is anticipated to result in profound widening of natural science knowledge.

Wisdom is the principal thing; therefore get wisdom; and with all thy getting, get understanding. Proverbs 4:7 In the early chapters of the book of Proverbs there is a strong emphasis on three words: knowledge, understanding, and wisdom. Perhaps we can apply these words to our philosophy behind the technology of Predictive Process Control. Knowledge is the accumulation of information provided by education as we begin to store the data in our brains that should prepare us for the challenges of the manufacturing environment. It applies to every level and every opportunity of education, formal and informal. This is simply to Know, without any requirement except a good memory, and is the basis for the following two thoughts. Understanding is the assimilation of knowledge, or the thinking process, as we begin to arrange and rearrange the data we Know for quick recall as it may be needed. This also applies to every level and opportunity of education. It is Know-Why based upon what we Know, and it requires some scepticism of oversimplified answers and a hunger for mental consistency. Wisdom is the application of both knowledge and understanding in real life enterprises. As we apply both our knowledge and understanding in those situations, all three are further enhanced by each progressive experience. This is that wonderful Know-How - to apply our education based upon Know-why, which was based upon Knowledge - which provides the confidence we need to advance in all phases of performance.

As we approach the end of the present century, the elementary particles of light (photons) are seen to be competing increasingly with the elementary particles of charge (electrons/holes) in the task of transmitting and processing the insatiable amounts of infonnation needed by society. The massive enhancements in electronic signal processing that have taken place since the discovery of the transistor, elegantly demonstrate how we have learned to make use of the strong interactions that exist between assemblages of electrons and holes, disposed in suitably designed geometries, and replicated on an increasingly fine scale. On the other hand, photons interact extremely weakly amongst themselves and all-photonic active circuit elements, where photons control photons, are presently very difficult to realise, particularly in small volumes. Fortunately rapid developments in the design and understanding of semiconductor injection lasers coupled with newly recognized quantum phenomena, that arise when device dimensions become comparable with electronic wavelengths, have clearly demonstrated how efficient and fast the interaction between electrons and photons can be. This latter situation has therefore provided a strong incentive to devise and study monolithic integrated circuits which involve both electrons and photons in their operation. As chapter I notes, it is barely fifteen years ago since the first demonstration of simple optoelectronic integrated circuits were realised using m-V compound semiconductors; these combined either a laser/driver or photodetector/preamplifier combination.

Infrared (IR) detectors fall into two main categories, thermal and photon. The earliest detectors of IR were thermal in nature, e.g. thermometers. The subsequent developments of these detectors, such as thermopiles, resistance bolometers, Golay cells and pyroelectric detectors, can operate at ambient temperature but have disadvantages of insensitivity and slowness. A wide variety of semiconductor photon detectors have been developed and these possess very high sensitivity, high frequency response but have the disadvantage of needing cryogenic cooling, particularly at longer wavelengths. In the main, the applications have been in the military sphere, but widespread industrial and scientific applications also exist. The majority of development funding for these semiconducting IR detectors has, however, come from military sources. This book is an attempt to provide an up-to-date view of the various IR detector/emitter materials systems currently in use or being actively researched. The book is aimed at newcomers to the field and at those already working in the IR industry. It is hoped that the former will find the book readable both as an introductory text and as a useful guide to the literature. Workers in one of the various IR areas will, hopefully, find the book useful in bringing them up-to-date with other, sometimes competing, technologies. To both groups of readers we trust that the book will prove interesting, thought-provoking and a spur to further progress in this fascinating and challenging field of endeavour.

The objectives of this book are twofold: 1. To provide a thorough examination of the materials science of cellulosic fibers with emphasis on the characterization of structure-property relations, and 2. To advance knowledge of how to best analyze cellulosic fibrous networks and composites, and, ultimately, engineer "e;novel"e; cellulose-based systems of superior performance and functionality. The design of new materials through the study of living systems, or bio-imitation, is burgeoning to become an established field, generally referred to as biomimetics. The latter, as with materials science, in general, prominently features multi-disciplinarity where new developments in mathematics, physics, chemistry and engineering continue to inspire novel areas of research and development. The book is structured in five chapters which provide a sequential treatment of the running theme: deformation mechanics and the physical, morphological and mechanical characterization of native cellulose fibers networks and composites. The heart of the book is Chapter 3, Damage Accumulation in Fibers, which treats the experimental methodology for fatigue testing of single fibers and the engendered results. In-depth examinations of the morphology, structure and chemical composition of native cellulose fibers, and the mechanics of deformation in these natural composite fibers are proffered in Chapters 1 and 2, respectively. The fourth chapter, Fractal Simulation of Crack Propagation, presents a fractal-based approach to modeling damage accumulation in materials. Fractals lend themselves well to modeling such randomly-oriented phenomena as crack propagation and fracture. The last chapter, Fibrous Structures: Networks and Composites, comprises analytical approaches for handling networks and composites.

Mechanical alloying (or mechanical milling) was invented in the 1970's as a method to develop dispersion-strengthened high temperature alloys with unique properties. With the discovery of formation of amorphous alloys using this technique, it has received new research interest in developing different material systems. Potential applications of this technique have been demonstrated in different areas of materials research. This book is intended as an introduction to mechanical alloying technique used in difference areas. This book contains basic information on the preparation of materials using the mechanical alloying technique. It is useful not only to undergraduate and post-graduate students, but also to scientists and engineers who wish to gain some understanding on the basic process and mechanisms of the process. The book begins with a brief introduction to provide a historical background understanding to the development of the mechanical alloying process. The experimental set-up in the alloying process is important. Currently there are different types of ball mills available. Some of them are specially designed for mechanical alloying process. Since the resultant materials are milling intensity and milling temperature dependent, ball mills should be carefully selected in order to obtain the desired materials and structures. This is discussed in chapter 2. The actual mechanical alloying process is being considered in Chapter 3. As it is essential to understand the use of processing control agents, the physical properties of some commonly used processing control agents are listed.

During September 24-26, 2001, the Faculty of Aerospace Engineering of the Delft University of Technology in the Netherlands organised the Glare - the New Material for Aircraft Conference, an international conference on the relationship between design, material choice and application of aircraft materials with respect to new developments in industry. Eminent representatives from the aircraft manufacturing world, including manufacturers, airlines, airports, universities, governments and aviation authorities, were present at this conference to meet and exchange ideas - see the group photo on the next two pages. The fact that the conference was held just two weeks after 'September 11, 2001' put things in a rather unique perspective. The aim of the conference was to illustrate the many unique applications of the Glare family of fibre metal laminates and to provide for the exchange and distribution of information regarding this material in order to stimulate their acceptance and promote further application. The introduction of fibre metal laminates into the commercial aviation market took about 20 years' time. Introducing new technologies should not be taken lightly, however; the aircraft industry is by nature rather conservative and innovations must therefore be proven - a paradox actually - in all possible ways before they can be introduced in real aircraft structures. Not only do technical aspects play a role in this respect; historical, cultural, economical and political issues are equally important.