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Since the discovery of high temperature superconductivity, a tidal wave of res­ earch into the newly found phenomena took off in several directions. The theor­ ists began to examine BSC and its implications. Mostly everyone was syn­ thesizing materials.The experimentalists were studying relations among electri­ cal and magnetic properties while the pure materials scientists began to exam­ ine the microstructures, and the relations of processing to one or two measurab­ le parameters. The engineering and systems community were preparing real conductors and designing the needed components. Each of the communities was holding between two and three annual meetings to discuss most recent re­ sults. As work progressed, and promised applications did not materialize, it became apparent to us that the physics and materials science communities needed to establish solid communication lines. This NATO Advanced Study Institute was thus conceived and organized. This was a two week summer school, which 15 internationally acclaimed physicists and material scientists were invited to par­ ticipate in the capacity of Lecturers. Eighty students, from 12 different countries, also attended.

URBAN WATER INFRASTRUCTURE NATO ADVANCED RESEARCH WORKSHOP SUMMARY 22-27 JUNE 1989 KYLE E SCHILLING P E Workshop Director The Workshop was based on the recognition that all NATO countries are concerned with similar water infrastructure issues. Present problems are aggravated by aging and neglected facilities, by inadequate financing and by water management institutions reflecting the needs of an earlier era. Service needs to be provided for expanding populations, at the same time that corrective measures must be taken for decaying older urban centers, resulting both from neglect and expiring service life. These needs exist within the framewode of other competing and conflicting uses for existing and yet to be developed water sources. The problems have generated some highly visible national debates over financing due to the large sums involved. Despite differences in the age of the North American, European and other societies, the technological ages of water supply and storm water systems are much the same and provide a common denominator in the worldwide trend to urbanization. Examination of approaches to urban water management also indicates that they are generally based on past experience and institutions created in a non-urban era. The physical, financial and institutional alternatives are consequently often out-of-step with current urban environment. Historically, the supply of adequate water and efficient storm water management have also been top priority items with water quality and other aspects of environmental protection assuming a lower priority after basic supply needs have been met.

One of the ultimate goals of materials research is to develop a fun­ damental and predictive understanding of the physical and metallurgical properties of metals and alloys. Such an understanding can then be used in the design of materials having novel properties or combinations of proper­ ties designed to meet specific engineering applications. The development of new and useful alloy systems and the elucidation of their properties are the domain of metallurgy. Traditionally, the search for new alloy systems has been conducted largely on a trial and error basis, guided by the skill and intuition of the metallurgist, large volumes of experimental data, the principles of 19th century thermodynamics and ad hoc semi-phenomenological models. Recently, the situation has begun to change. For the first time, it is possible to understand the underlying mechanisms that control the formation of alloys and determine their properties. Today theory can begin to offer guidance in predicting the properties of alloys and in developing new alloy systems. Historically, attempts directed toward understanding phase stability and phase transitions have proceeded along distinct and seemingly diverse lines. Roughly, we can divide these approaches into the following broad categories. 1. Experimental determination of phase diagrams and related properties, 2. Thermodynamic/statistical mechanical approaches based on semi­ phenomenological models, and 3. Ab initio quantum mechanical methods. Metallurgists have traditionally concentrated their efforts in cate­ gories 1 and 2, while theoretical physicists have been preoccupied with 2 and 3.

The 6th course of the futernational School of Solid State Physics was held in Erice, Sicily, at the Ettore Majorana Centre for Scientific Culture, 19-29 June, 1995. The course was organized as a NATO Advanced Study Institute and received generous support from NATO's Nanoscale Science Program. This volume is based on the lectures presented during the course. fudispensable for the planning of the summer school was the support of the Director of the Ettore Majorana Centre, Professor A. Zichichi. We wish to express our sincere appreciation to the center staff, Dr. Maria Zaini, Dr. Alberto Gabriele, Dr. Pinola Savalli and Dr. Jerry Pilarski for their expert assistance in all organizational matters. A special word of thanks must go to the director of the International School of Solid State Physics, Professor Giorgio Benedek, not only for his valuable advice in the planning stage, but also for his active participation in the program itself. I would like to thank my coworkers, Stefan Frank, Nikola Malinowski, Renee Stotz, Frank Tast and Kristin Wirth for their valuable assistance in preparing these proceedings of the meeting. The success of a school is, in the last analysis, determined by the inter­ est and commitment of the lecturers and participants. I am very grateful to the lecturers for their carefully prepared formal presentations, to the par­ ticipants for their contributions to the spontaneous evening "workshops", and to all for their inexhaustible enthusiasm.

John Keats, writing to Fanny Brawne [1], said "I long to believe in immortality ¿¿¿¿¿ I wish to believe in immortality - I wish to live with you forever". So much of this talk will be concerned with the ductile behaviour of crystals, plasticity in its narrower sense. We shall consider a crystal which is deforming by slip, and shall expose a surface in this crystal. We first think of the sur­ face as a simple mathematical cut along a low-index plane. Then we allow for the relaxation of the newly-exposed atoms, and for surface irregularities, and we consider the effect of lattice va­ cancies which can enter at the surface. We consider the effect of dissolving off the surface layers, either intermittently or contin­ uously. Then the effects of adsorption or oxidation by normal con­ stituents of the atmosphere must be considered, the effects of sur­ face alloying, and finally those of special surface-active agents. But "All/Life death does end and each day dies with sleep" [2], and plasticity in its broader sense includes the fracture ~'1hich term­ inates flow. Here there is a bewildering array of effects. The medium in which the crystal flows may enhance its ductility enor­ mously, or it may cause it to break almost without plastic deform­ ation, or under a load which it has already supported.

Model based control has emerged as an important way to improve plant efficiency in the process industries, while meeting processing and operating policy constraints. The reader of Methods of Model Based Process Control will find state of the art reports on model based control technology presented by the world's leading scientists and experts from industry. All the important issues that a model based control system has to address are covered in depth, ranging from dynamic simulation and control-relevant identification to information integration. Specific emerging topics are also covered, such as robust control and nonlinear model predictive control. In addition to critical reviews of recent advances, the reader will find new ideas, industrial applications and views of future needs and challenges. Audience: A reference for graduate-level courses and a comprehensive guide for researchers and industrial control engineers in their exploration of the latest trends in the area.

The main motivation for the organization of the Advanced Research Workshop in Belgirate was the promotion of discussions on the most recent issues and the future perspectives in the field of Solid State lonics. The location was chosen on purpose since Belgirate was the place were twenty years ago, also then under the sponsorship of NATO, the very first international meeting on this important and interdisciplinary field took place. That meeting was named "e;Fast Ion Transport in Solids"e; and gathered virtually everybody at that time having been active in any aspect of motion of ions in solids. The original Belgirate Meeting made for the first time visible the technological potential related to the phenomenon of the fast ionic transport in solids and, accordingly, the field was given the name "e;Solid State lonics"e;. This field is now expanded to cover a wide range of technologies which includes chemical sensors for environmental and process control, electrochromic windows, mirrors and displays, fuel cells, high performance rechargeable batteries for stationary applications and electrotraction, chemotronics, semiconductor ionics, water electrolysis cells for hydrogen economy and other applications. The main idea for holding an anniversary meeting was that of discussing the most recent issues and the future perspectives of Solid State lonics just twenty years after it has started at the same location on the lake Maggiore in North Italy.

In the near future the world will need to convert to a suitable, clean energy supply: one that will meet the demands of an increasing population while giving few environmental problems. One such possible supply is hydrogen. Hydrogen Energy System describes the present status of hydrogen as an energy supply, as well as its prospect in the years to come. It covers the transition to hydrogen-based, sustainable energy systems, the technology of hydrogen production, its storage and transport, and current and future hydrogen utilisation. Economic analyses of the hydrogen energy system, together with case studies, are also presented.

A detailed study of the science, engineering and applications of terahertz technology, based on room-temperature solid-state devices, which are seen as the key technology for wider applications in this frequency range. The relative merits of electronic and optical devices are discussed and new device principles identified. Issues of terahertz circuit design, implementation and measurement are complemented by chapters on current and future applications in communications, sensing and remote surveillance. Audience: The unique coverage of all aspects of terahertz technology will appeal to both new and established workers in the field, as well as providing a survey for the interested reader.

Photonic band gap crystals offer unique ways to tailor light and the propagation of electromagnetic waves. In analogy to electrons in a crystal, EM waves propagating in a structure with a periodically-modulated dielectric constant are organized into photonic bands separated by gaps in which propagating states are forbidden. Proposed applications of such photonic band gap crystals, operating at frequencies from microwave to optical, include zero- threshold lasers, low-loss resonators and cavities, and efficient microwave antennas. Spontaneous emission is suppressed for photons in the photonic band gap, offering novel approaches to manipulating the EM field and creating high-efficiency light-emitting structures. Photonic Band Gap Materials identifies three most promising areas of research. The first is materials fabrication, involving the creation of high quality, low loss, periodic dielectric structures. The smallest photonic crystals yet fabricated have been made by machining Si wafers along (110), and some have lattice constants as small as 500 microns. The second area is in applications. Possible applications presented are microwave mirrors, directional antennas, resonators (especially in the 2 GHz region), filters, waveguides, Y splitters, and resonant microcavities. The third area covers fundamentally new physical phenomena in condensed matter physics and quantum optics. An excellent review of recent development, covering theoretical, experimental and applied aspects. Interesting and stimulating reading for active researchers, as well as a useful reference for non-specialists.

Techniques for the preparation of condensed matter systems have advanced considerably in the last decade, principally due to the developments in microfabrication technologies. The widespread availability of millikelvin temperature facilities also led to the discovery of a large number of new quantum phenomena. Simultaneously, the quantum theory of small condensed matter systems has matured, allowing quantitative predictions. The effects discussed in Quantum Dynamics of Submicron Structures include typical quantum interference phenomena, such as the Aharonov-Bohm-like oscillations of the magnetoresistance of thin metallic cylinders and rings, transport through chaotic billiards, and such quantization effects as the integer and fractional quantum Hall effect and the quantization of the conductance of point contacts in integer multiples of the `conductance quantum'. Transport properties and tunnelling processes in various types of normal metal and superconductor tunnelling systems are treated. The statistical properties of the quantum states of electrons in spatially inhomogeneous systems, such as a random, inhomogeneous magnetic field, are investigated. Interacting systems, like the Luttinger liquid or electrons in a quantum dot, are also considered. Reviews are given of quantum blockade mechanisms for electrons that tunnel through small junctions, like the Coulomb blockade and spin blockade, the influence of dissipative coupling of charge carriers to an environment, and Andreev scattering. Coulomb interactions and quantization effects in transport through quantum dots and in double-well potentials, as well as quantum effects in the motion of vortices, as in the Aharonov-Casher effect, are discussed. The status of the theory of the metal-insulator and superconductor-insulator phase transitions in ordered and disordered granular systems are reviewed as examples in which such quantum effects are of great importance.

Intersubband transitions in quantum wells have attracted tremendous attention in recent years, mainly due to the promise of applications in the mid and far-infrared regions (2--20 mum). Many of the papers presented in Quantum Well Intersubband Transition Physics and Devices are on the basic linear intersubband transition processes, detector physics and detector application, reflecting the current state of understanding and detector applications, where highly uniform, large focal plane arrays have been demonstrated. Other areas are still in their early stages, including infrared modulation, harmonic generation and emission.

Chemical reactor engineering, as a discipline, has a central role to play in helping with the development of adequate strategies and technologies that can deal effectively with the concerns of today's society, which are increasingly becoming attuned to the environment. The current challenge is how to adapt present processes and products to meet more rigorous environmental standards. Chemical Reactor Technology for Environmentally Safe Reactors and Products addresses these issues in three parts: I -- Fuels of the Future and Changing Fuel Needs; II -- Alternative Sources; III -- Emission Control, Chemical Reactor Safety and Engineering. Attention is also paid, throughout the text, to the fundamental technological aspects of reactor engineering and to possible strategies for bridging knowledge gaps.

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.

In the ten years since the scientific rationale for the design, synthesis and application of inorganic and organometallic polymers (IOPs) was first conceptualised, we have witnessed the first tentative exploration of IOPs as precursors to new materials, with efforts focusing on the design and synthesis of novel ceramic precursors. Developing expertise led to precursor studies combined with the characterisation of the transformation processes that occur when IOPs are converted to ceramic materials. Now at maturity, the science presented in this volume reveals the polymer precursor approach to materials synthesis together with examples of processing ceramic shapes for a range of mechanical properties, the development of sophisticated, noninvasive analytical techniques, and IOP design rationales relying on well-defined processing-property relationships. The production of multifunctional IOPs is described, providing ion conductivity, gas sensing, bioactivity, magnetic properties, etc., combined with processability. The existence of well-defined IOPs and the exquisite control that can be exerted on sol-gel systems now provide access to such a variety of mixed organic-organometallic and/or inorganic hybrid systems that their exploitation is likely to develop into an entirely new field of materials chemistry. Future exciting avenues of research are also being opened up with the advent of buckyballs, Met-Cars, dopable preceramics, rigid-rod organometallics, and molecular tinkertoys.

Materials and Processes for Surface and Interface Engineering, which has been written by experts in the fields of deposition technology and surface modification techniques, offers up to date tutorial papers on the latest advances in surface and interface engineering. The emphasis is on fundamental aspects, principles and applications of plasma and ion beam processing technology. A handbook for the engineer and scientist as well as an introduction for students in several branches of materials science and surface engineering.

The first NATO Advanced Workshop on Quantum Tunneling of Magnetization (QTM) was organized and co-directed by Bernard Barbara, Leon Gunther, Nicolas Garcia, and Anthony Leggett and was held from June, 27 through July 1, 1994 in Grenoble and Chichilianne, France. These Proceedings include twenty-nine articles that represent the contributions of the participants in the Workshop. Quantum Tunneling of Magnetization is not only interesting for purely academic reasons. It was pointed out in the review article by L. Gunther in the December, 1990 issue of Physics World, that QTM may be destined to play a significant role within the next two decades in limiting the density of information storage in magnetic systems. Recent advances have indicated that this limitation may well be reached even earlier than first predicted. Furthermore, the number of people who have entered the field of study of QTM during these past few years has increased many fi)ld. The time was therefore opportune to hold a Workshop to bring together for the first time the leading researchers of QTM, both theoretical and experimental, so as to discuss the current status of the field. The most controversial issue at the time of the Workshop was how to establish r.eliable criteria for determining whether experimental results do indeed reveal manifestations of QTM. We believe that much progress was made at the Workshop on this issue.

The second half of this century will remain as the era of proliferation of electronic computers. They did exist before, but they were mechanical. During next century they may perform other mutations to become optical or molecular or even biological. Actually, all these aspects are only fancy dresses put on mathematical machines. This was always recognized to be true in the domain of software, where "e;machine"e; or "e;high level"e; languages are more or less rigourous, but immaterial, variations of the universaly accepted mathematical language aimed at specifying elementary operations, functions, algorithms and processes. But even a mathematical machine needs a physical support, and this is what hardware is all about. The invention of hardware description languages (HDL's) in the early 60's, was an attempt to stay longer at an abstract level in the design process and to push the stage of physical implementation up to the moment when no more technology independant decisions can be taken. It was also an answer to the continuous, exponential growth of complexity of systems to be designed. This problem is common to hardware and software and may explain why the syntax of hardware description languages has followed, with a reasonable delay of ten years, the evolution of the programming languages: at the end of the 60's they were"e; Algol like"e; , a decade later "e;Pascal like"e; and now they are "e;C or ADA-like"e;. They have also integrated the new concepts of advanced software specification languages.

Proceedings of the NATO Advanced Research Workshop, Ringberg in Rottach Egern, Germany, February 20--24, 1995

Corrosion behaviour is one of the most poorly understood characteristics of ceramics. A balanced mixture of scientists from material science, metallurgy, physics, chemistry and mineralogy sum up the state of the art of measurement and modelling and reveal future research directions. The book reviews the theory of corrosion of ceramics, including the diffusion of gases and the predictions of thermodynamics; it discusses critically the kinetic models and representation tools for layer growths and material destruction. Corrosion of nitrides, carbides and oxides by simple and complex gases (O2, H2O, SO2, halides) and melts (ionic and metallic) reveal current measurement and modelling methods, advanced experimental techniques, such as laser diagnostics, TV holography, Raman spectroscopy and NDE surface methods. Frontier areas (e.g. the modelling of porous materials corrosion and protection) are revealed. For scientists and engineers in materials science, dealing with ceramics and their application. A valuable source for research students, solid state physicists and physical chemists.

An understanding of the processes involved in the basic and applied physics and chemistry of the interaction of plasmas with materials is vital to the evolution of technologies such as those relevant to microelectronics, fusion and space. The subjects dealt with in the book include: the physics and chemistry of plasmas, plasma diagnostics, physical sputtering and chemical etching, plasma assisted deposition of thin films, ion and electron bombardment, and plasma processing of inorganic and polymeric materials. The book represents a concentration of a substantial amount of knowledge acquired in this area - knowledge which was hitherto widely scattered throughout the literature - and thus establishes a baseline reference work for both established and tyro research workers.