NATO Science Series E: – serie

Much has been said and written about the abilities of modern instrumentation to help solve problems of combustion in engines. In the main, however, the design and fabr ication of combustion chambers continues to be based on extrapolation of exper ience gained from use and rig tests, with little input from advanced techniques such as those based on optical diagnotics. At the same time, it has become increasingly difficult to design better combustion chambers without knowledge of the relevant flow processes. Thus, the future must involve improved understanding which, in turn, will require detailed measurements of velocity, temperature and concentration. The need to narrow the gap between current industrial practice and the acquisition and implementation of improved techniques motivated the organization of the Advanced Study Institute upon which this volume is based. This Institute on Instrumentation for Combustion and Flow in Engines was arranged to display the needs of industry and the possibilities made available by modern instrumentation and, at the same time, to make clear the relative advantages of optical and probe techniques. Held at Vimeiro during the period from 13 to 26 September, 1987, the Institute was attended by 120 participants and 16 invited lecturers.

Proceedings of the NATO Advanced Study Institute, Cargese, Corsica, France, 18-31 July, 1988

Proceedings of the NATO Advanced Study Institute, Cargese, Corsica, France, 18-31 July, 1988

Adsorption processes have experienced a significant growth in the last decades. This growth was a result of scientific and technological advances which generated new adsorbents as well as new concepts for processing systems (UOP's "Sorbex" process and PSA cycles). The expectations for a continued development of adsorption are high since process engineering is deeply concerned with intensive processes using less energy. Adsorption processes are also relevant to the increasingly important area of biotechonology. The development of affinity processes is a creative synthesis of biochemistry,molecular biology and chemical engineering. This NATO Advanced Study Institute on "ADSORPTION:SCIENCE and TECHNOLOGY" had as a primary objective to provide an updated treatment of the fundamentals of adsorption and adsorption processes. The lectures presented at the Institute are collected in this volume together with a few papers presented by participants. The material is arranged in four sections.Part I deals with the characterization of adsorption and thermodynamics of adsorption,namely the correlation of equilibrium data.Part II covers the kinetics of adsorption and fixed-bed processes (equilibrium theory,design aspects, adsorptive reactors).Part III is an extensive coverage of cyclic processes (pressure swing adsorption and thermal swing adsorption) and simulated moving beds (modeling for process optimization and industrial applications).Finally Part IV deals with applications mainly in biotechnolo gy (con tin uous adsorption, affini ty chrom atography, gel permeation,chromatographic reactors,scale-up methods).

This volume contains the edited version of lectures and selected research contributions presented at the NATO ADVANCED STUDY INSTITUTE on ADVANCES IN FATIGUE SCIENCE AND TECHNOLOGY. held in Alvor. Portugal, 4th to 15th of April 1988. and organized by CEMUL - Center of Mechanics and Materials of The Technical University of Lisbon. The Institute was attended by 101 participants, including 15 lecturers. from 14 countries. The participants were leading scientists and engineers from universities, research institutions and industry. and also Ph.D~ students. Some participants presented papers during the Institute reporting the state-of-art of their research projects. All the sessions wel'e very active and quite extensive discussions on scientific aspects took place during the Institute. The Advanced Study Institute provided a forum for interaction among eminent scientists and engineers. from different schools of thought and young researchers. The Institute addressed the foundations and current state of the art of essential aspects related to fatigue science and technology, namely: Short Cracks, Metallurgical Aspects, Environmental Fatigue, Threshold Behaviour, Notch Behaviour. Creep and Fatigue Interactions at High Temperature, Multiaxial Fatigue, Low Cycle Fatigue, Methodology of Fatigue Testing, Variable Amplitude Fatigue, Fatigue of Advanced Materials. Elastic-Plastic Fatigue, and several engineering applications such as welded joints, energy systems, offshore structures, automotive industry, machine and engine components. This book is organized in three parts: Part I: Fundamentals of Fatigue Part II: Engineering Applications Part III: Research Contributions The research contributions covered most of the areas referred above.

This book contains the papers that were accepted for presentation at the 1988 NATO Advanced Study Institute on Underwater Acoustic Data Processing, held at the Royal Military College of Canada from 18 to 29 July, 1988. Approximately 110 participants from various NATO countries were in attendance during this two week period. Their research interests range from underwater acoustics to signal processing and computer science; some are renowned scientists and some are recent Ph.D. graduates. The purpose of the ASI was to provide an authoritative summing up of the various research activities related to sonar technology. The exposition on each subject began with one or two tutorials prepared by invited lecturers, followed by research papers which provided indications of the state of development in that specific area. I have broadly classified the papers into three sections under the titles of I. Propagation and Noise, II. Signal Processing and III. Post Processing. The reader will find in Section I papers on low frequency acoustic sources and effects of the medium on underwater acoustic propagation. Problems such as coherence loss due to boundary interaction, wavefront distortion and multipath transmission were addressed. Besides the medium, corrupting noise sources also have a strong influence on the performance of a sonar system and several researchers described methods of modeling these sources.

Photonics, the counterpart of electronics, involves the usage of Photons instead of electrons to process information and perform various switching operations. Photonics is projected to be the technology of the future because of the gain in speed, processing and interconnectivity of network. Nonlinear optical processes will play the key role in photonics Where they can be used for frequency conversion, optical switching and modulation. Organic molecules and polymers have emerged as a new class of highly promising nonlinear optical materials Which has captured the attention of scientists world wide. The organic systems offer the advantage of large nonresonant nonlinearities derived from the 1T electrons contribution, femtosecond response time and the flexibility to modify their molecular structures. In addition, organic polymers can easily be fabricated in various device structures compatible with the fiber-optics communication system. The area of nonlinear optics of organic molecules and polymers offers exciting opportunities for both fundamental research and technologic development. It is truly an interdisciplinary area. This proceeding is the outcome of the first NATO Advanced Research WOrkshop in this highly important area. The objective of the workshop was to provide a forum for scientists of varying background from both universities and industries to come together and interface their expertize. The scope of the workshop was multidisciplinary with active participations from Chemists, physicists, engineers and materials scientists from many countries.

The primary thrust of very large scale integration (VLS!) is the miniaturization of devices to increase packing density, achieve higher speed, and consume lower power. The fabrication of integrated circuits containing in excess of four million components per chip with design rules in the submicron range has now been made possible by the introduction of innovative circuit designs and the development of new microelectronic materials and processes. This book addresses the latter challenge by assessing the current status of the science and technology associated with the production of VLSI silicon circuits. It represents the cumulative effort of experts from academia and industry who have come together to blend their expertise into a tutorial overview and cohesive update of this rapidly expanding field. A balance of fundamental and applied contributions cover the basics of microelectronics materials and process engineering. Subjects in materials science include silicon, silicides, resists, dielectrics, and interconnect metallization. Subjects in process engineering include crystal growth, epitaxy, oxidation, thin film deposition, fine-line lithography, dry etching, ion implantation, and diffusion. Other related topics such as process simulation, defects phenomena, and diagnostic techniques are also included. This book is the result of a NATO-sponsored Advanced Study Institute (AS!) held in Castelvecchio Pascoli, Italy. Invited speakers at this institute provided manuscripts which were edited, updated, and integrated with other contributions solicited from non-participants to this AS!.

The primary thrust of very large scale integration (VLS!) is the miniaturization of devices to increase packing density, achieve higher speed, and consume lower power. The fabrication of integrated circuits containing in excess of four million components per chip with design rules in the submicron range has now been made possible by the introduction of innovative circuit designs and the development of new microelectronic materials and processes. This book addresses the latter challenge by assessing the current status of the science and technology associated with the production of VLSI silicon circuits. It represents the cumulative effort of experts from academia and industry who have come together to blend their expertise into a tutorial overview and cohesive update of this rapidly expanding field. A balance of fundamental and applied contributions cover the basics of microelectronics materials and process engineering. Subjects in materials science include silicon, silicides, resists, dielectrics, and interconnect metallization. Subjects in process engineering include crystal growth, epitaxy, oxidation, thin film deposition, fine-line lithography, dry etching, ion implantation, and diffusion. Other related topics such as process simulation, defects phenomena, and diagnostic techniques are also included. This book is the result of a NATO-sponsored Advanced Study Institute (AS!) held in Castelvecchio Pascoli, Italy. Invited speakers at this institute provided manuscripts which were edited, updated, and integrated with other contributions solicited from non-participants to this AS!.

The growing use of mathematical models in hydraulics has not made physical models obsolete. They keep pace with mathematical models and in some cases make progress in conjunction with them Physical models continue to be developed: more precise use of similitude criteria, better knowledge of scale effects, new and more complex types of model,use of various artifices, more ade- quate instrumentation, automation of the operation of model- all these pOint to that development. What was needed was to make a survey of the situation, and this was the principal aim of the NATO Advanced Study Institute on Recent Advances in Hydraulic Physical Modelling, which took place on the premises of the Laborat6rio Nacional de Engenharia Civil (LNEC) in Lisbon, Portugal, from 4th to 15th July 1988, and of which this book is one of the main outputs. It is divided into 11 chapters, corresponding to 28 lectures that cover five areas: fundamentals of physical modelling, river models, hydraulics of structures, maritime hvdraulics and densi ty models. -- Hodelling is obviously dependent on the knowledge of the phe- nomena that are being modelled.This book is therefore also a book on hydraulic engineering in general and not only on phv- sical, modelling. The text also refers to mathematical modelling, experimental methods in hydraulics and observation of nature and prototypes.

Even though most of the biomass of the planet is in forests, we live in a world where wood as a raw material and its products are increasingly scarce. This is particularly so in important areas such as the European Community, which is far from self-sufficient in terms of wood. In recent years the need to intensify forest production and, in some cases, to uti­ lize abandoned agricultural land for forestry has focussed world-wide attention on the economic importance of fast-growing tree plantations. These are usually managed as short "rotations" (growing cycles) of less than 15 years, often for the production of industrial raw materials or biomass for energy. Under the designation of fast-growing tree plantations, or short­ rotation silviculture, one may find ecosystems managed for different economic objectives, with different intensities of technical intervention and different levels of productivity. They may include any of a wide range of species grown under various environmental conditions. A common factor, however, is the greater possibility that exists, relative to conventional forestry, for manipulation of both the environment and the genetics of the trees.

r. portance of Energy Storage 1 B. 11lk1 and S. Iaka~ Thermal Energy Storage Systems and Their Dynamic Behavior 11 W. J. Yang Second Law Optimization of Thermal Energy Storage Systems: 37 Fundaaentals and Sensible Heat Systems R. J. Irane Second Law Optimization of Thermal Energy Storage Systems: 69 Latent Heat Systems R. J. Irane Design,Optimization and Control of a Thermal Energy Storage System 89 Y. Jaluria A MOdel for Energy Retrieval from a Thermal Storage 117 G. Cossali, G. de Giorgio and L. Mazzarella Storage of Solar Thermal Energy 129 S. Iaka~. E. Payko~ and Y. Yener Thermal Energy Storage and Extraction in Solar Ponds 163 Y. Jaluria Phase Change Heat Transfer in Cylindrical Domain: MOdelling and 191 Its Importance in the Thermal Energy Storage M. Toksoy and B. Z. ilken Solar Energy Storage in Packed Beds 231 W. J. Yang Expert. ental and Numerical MOdelling of Solar Energy Storage in 249 Rockbeds and Encapsulated Phase Change Material Packings J. M. Buchlin New Approaches to Heat Storage in Buildings 303 C. J. Swet Thermal Energy Storage for Cooling in Commercial Buildings 315 H. Akbari and A. Mertol Cool Storage for Solar and Conventional Air Conditioning 349 C. J.Swet The Importance of Heat Storage When Using Cogeneration Plants in Cold 369 Climates A. Haag Gravity-Assisted Melting in Enclosures 383 S. Sengupta and S. K. Roy Energy Storage and Nuclear Reactors 415 N. Aybers Comparison of Solar-Hydrogen with Synthetic Fossil Fuels 431 T. N.

Food properties, whether they concern the physical, thermodynamic, chemical, nutritional or sensory characteristics of foods, play an important role in food processing. In our quest to gain a mechanistic understanding of changes occurring during food processing, the knowledge of food properties is essential. Quantitative information on the food properties is necessary in the design and operation of food processing equipment. Foods, because of their biological nature and variability, vary in the magnitude of their properties. The variation in properties offer a challenge both in their measurement and use in the food processing applications. Often a high level of precision in measurement of properties is not possible as the measurement method may itself cause changes to the product, resulting in a variation in the obtained values. Recognizing the difficulties in measurement of food properties, and the lack of completeness of such information, several research programs have been in existence during the last two decades. In Europe, a multinational effort has been underway since 1978. The first project supported by COST (European Cooperation in the Field of Scientific and Technical Research), was titled COST 90 "The Effect of Processing on the Physical Properties of Foodstuffs". This and another project COST 90bis have considerably added to our knowledge of measurement methods and data on a number of physical properties. Two publications that summarize the work conducted under 1 2 these projects are Physical Properties of Foods and Physical Properties of Foods .

The genesis of this conference was on a quay of the port of Bergen in March 1985. Ragnar Amason suggested to Phil Neher a small, mid-Atlantic conference on recent developments in fishery management. In the event, more than twenty papers were scheduled and over one hundred and fifty conferees were registered. Logistical complications were sorted through for a summer 1988 conference in Iceland. The really innovative management programs were in the South Pacific; Aus­ tralia and New Zealand had introduced Individual Transferable Quotas (ITQs); and Iceland, Norway and Canada were also experimenting with quotas. It seemed to the program committee (Rognvaldur Hannesson and Geoffrey Waugh were soon on­ board) that these quotas had more or less characteristics of property rights. Property rights were also taking other forms in other places (time and area licenses, restrictive licensing of vessels and gear, traditional use rights). The idea of rights based fishing became the theme of the conference.

Agricultural soils are subjected to many applied mechanical stresses that influence their behavior. Stresses arise from tillage machines, seeders and chemicals applicators, tractors, and equipment for harvest and transport. Applied stresses may compact or loosen the bulk soil. Micro sections of soil (aggregates or clods) may be compacted during tillage while the bulk soil is loosened. Because most granular soils are combined into structural units of varying sizes with different strengths and properties, prediction of the effect of stresses on the behavior of bulk soils is difficult. The basic strength properties of soil are determined by many fac­ tors: the size distribution of particles, chemical and mineralogical properties of inorganic clay fraction, the organic matter content and composition, the water content and the stress history. These factors combine and interact to produce many possible behavior patterns. Changes in structure of the soil from applied stresses and biologi­ cal reactions may profoundly influence storage and transmission of water, heat, and air, and the mechanical resistance to penetration by plant roots. They may also affect the traction of vehicles. Manipulation of structural properties of soils by tillage implements is a major cost under most crop production systems. Reduced energy use is also a significant conservation objective. Improved management systems are very dependent upon a better understanding of soils' response to applied stresses. The content of this book resulted from a NATO Advanced Research Workshop held in St. Paul, Minnesota, U.S.A. September 13-16, 1988.

T~~botogy and Vynam~c~ a~e u6uatty con6~de~ed a~ 6epa~ate 6ubject6. Acco~d~ngty, ~e6ea~che~6 ~n th06e two 6~etd6 6etdom meet, de6p~te, the 6act that the~e ~6 a con~~de~a- bie ove~tap 06 ~nte~e~t~ namety when deat~ng w~th ~otat~ng mach~ne~y cond~t~on mon~to~~ng. Rotat~ng mach~ne~ a~e u~ed ~n atmo~t eve~y ~ndu~t~~at appt~cat~on namety m~t~ta~y, powe~ gene~at~on, chem~cat , 600d p~oce6~~ng, etc. Any powe~ u~e~ o~ gene~at~ng ~y~tem ~6 ba6ed on ~otat~ng mach~ne~ 6uch a~ tu~b~ne~, 6an~, pump6, comp~e~~o~~, etc. mak~ng the ~c~ent~6ic e660~t~ in the 6~etd 06 ~otat~ng mach~ne~y in ~ecent yea~~ wett ju~t~6~ed. Fa~tu~e 06 ~otat~ng component~, due to wea~ andlo~ v~b~a- t~on p~obtem~, ~~ 6t~tt d~66~cutt to p~ed~ct and ~e~utt~ 6~eQuentty 6~om ~nadeQuaxe de~~gn. Thi~ i~ o~iginaxed by ~mpe~6ecx knowtedge 06 the acxuat behav~ou~ 06 xhe ~y~tem~ Ve~pixe xhe p~og~e~~ achieved in xhe 6ietd~ 06 x~ibotogy and dynamic~, a tack 06 communicaxion ctea~ty ~xitl exi~x~ between xh06e ~nvolved in de~ign and developmenx ~n ind- x~y and ~e~ea~ch team~ in un~ve~~ixie6 and othe~ li~hmenx~.B~inging togethe~ x~ibotog~6t~ and dynam~c~6t~ ~n o~de~ xo cont~ibute xo inc~ea6e p~og~e~6 ~n both 6ietd~ wa~ the main object~6 06 the NATO AVVANCEV STUVY INSTITUTE (ASI) on "VIBRATION ANV WEAR VAMAGE IN HIGH SPEW ROTATING MACHINERY" hetd ~n T~oia, Po~xugat, 10xh to 22nd Ap~il 1989, and o~ga- n~zed by CEMUL-Cente~ 06 Mechan~c~ and Maxe~ial~ 06 the Technicat Un~ve~~~ty 06 Li~bon.

This publication is a compilation of papers presented at the Semiconductor Device Reliabi­ lity Workshop sponsored by the NATO International Scientific Exchange Program. The Workshop was held in Crete, Greece from June 4 to June 9, 1989. The objective of the Workshop was to review and to further explore advances in the field of semiconductor reliability through invited paper presentations and discussions. The technical emphasis was on quality assurance and reliability of optoelectronic and high speed semiconductor devices. The primary support for the meeting was provided by the Scientific Affairs Division of NATO. We are indebted to NATO for their support and to Dr. Craig Sinclair, who admin­ isters this program. The chapters of this book follow the format and order of the sessions of the meeting. Thirty-six papers were presented and discussed during the five-day Workshop. In addi­ tion, two panel sessions were held, with audience participation, where the particularly controversial topics of bum-in and reliability modeling and prediction methods were dis­ cussed. A brief review of these sessions is presented in this book.

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.

Conventional synthetic materials, like metals, ceramics or glass, are usually isotropic substances, and their suitability for structural applications is achieved by morphological design and combination in the macroscopic scale. However, in modem engineering this is often not acceptable. As an alternative, the use of non-homogeneous, anisotropic materials, with significant stiffness and strength only in the directions these mechanical properties are really needed, can lead to enormous material (and weight) savings. This is the case of multiphase systems called composite materials. In these composites, different material parts are added and arranged geometrically, under clearly designed and controlled conditions. Usually, a structure of fibers provides strength and stiffness and a matrix helds them together, whilst providing the geometric form. Carbon fibers are among the high-performance fibers employed in these advanced structural composites, which are profoundly changing many of today's high technology industries. New research and development challenges in this area include upgrading the manufacturing process of fibers and composites, in order to improve characteristics and reduce costs, and modifying the interfacial properties between fibers and matrix, to guarantee better mechanical properties. The interdisciplinary nature of this "new frontier" is obvious, involving chemistry, materials science, chemical and mechanical engineering. Other topics, which more often are treated separately, are also important for the understanding of the processes of fiber production. Carbon filaments is one such topic, as the study of their mechanisms of nucleation and growth is clearly quite relevant to the production of vapour-grown carbon fibers.

This volume is the proceedings of the NATO Advanced Study Institute, "Diffusion in Materials", held at "Centre Paul Langevin", Aussois, during March 12-25, 1989. There were 105 participants of whom 24 were lecturers and members of the international advisory committee. In addition to the participants from NATO countries, a small number of participants came from Australia, Hungary, Poland and Tunisia. The principal aim of the organizing committee was to bring together scientists of wide interest and expertise in the field of diffusion and to familiarize the young workers in material science with the wide range of theoretical models and methods and of experimental techniques . The Institute was concerned with the study of diffusion and related phenomena in solids which are at the cutting edge of novel technologies. The discussion of basic theories of defects in solids and their transport, with their applications in the understanding of diffusion processes in "simple solids" was followed by the wide range of current theoretical models and methods, experimental techniques and their potential. The lectures on the diffusion in specific materials included : metals, dilute and concentrated alloys, simple and compound semiconductors, stoichiometric and non-stoichiometric oxides, high-Tc compounds, carbides, nitrides, silicates, conducting polymers and thin films, ionic, superionic, amorphous and irradiated materials.

This book constitutes the Proceedings of the NATO Advanced Research Workshop on Conjugated Polymers held at the University of Mons, Belgium, during the first week of September 1989. The Workshop was attended by about fifty scientists representing most of the leading research groups within NATO countries, that have contributed to the development of conjugated polymeric materials. The program was focused on applications related to electrical conductivity and nonlinear optics. The attendance was well balanced with a blend of researchers from academic, industrial, and government labs, and including synthetic chemists, physical chemists, physicists, materials scientists, and theoreticians. The Workshop provided an especially timely opportunity to discuss the important progress that has taken place in the field of Conjugated Polymers in the late eighties as well as the enormous potential that lies in front of us. Among the recent significant developments in the field, we can cite for instance: (i) The discovery of novel synthetic routes affording conjugated polymers -that are much better characterized, especially through control of the molecular weight; - that can be processed from solution or the melt; the early promise that conducting polymcrs would constitute materials combining the electrical conductivities of metals with the mechanical properties of plastics is now being realized; -that can reach remarkably high conductivities.

Proceedings of the NATO Advanced Study Institute on Basic Concepts and Applications of Scanning Tunneling Microscopy, Erice, Italy, April 17-29, 1989

Proceedings of the NATO Advanced Research Workshop, Manchester, UK, September 18-22, 1989

Proceedings of the NATO Advanced Research Workshop on New Biosynthetic Biodegradable Polymers of Industrial Interest from Microorganisms, Sitges, Spain, May 26-31, 1990

Evaluation, repair and rehabilitation of bridges are increasingly important topics in the effort to deal with the deteriorating infrastructure. For example, in the United States about 40 percent of the nation's 570,000 bridges are classified, according to the Federal Highway Administra­ tion's (FHW A) criteria, as deficient and in need of rehabilitation and replacement. In other countries the situation is similar. FHW A estimates the cost of a bridge replacement and reha­ bilitation program at 50 billion dollars. The major factors that have contributed to the present situation are: the age, inadequate maintenance, increasing load spectra and environmental contamination. The deficient bridges are posted, repaired or replaced. The disposition of bridges involves clear economical and safety implications. To avoid high costs of replacement or repair, the evaluation must accurately reveal the present load carrying capacity of the struc­ ture and predict loads and any further changes in the capacity (deterioration) in the applicable time span. Accuracy of bridge evaluation can be improved by using the recent developments in bridge diagnostics, structural tests, material tests, structural analysis and probabilistic methods. There is a need for an international exchange of advanced experience to increase the research effi­ ciency. The Workshop is organized on the premise that the exchange of existing American and European experience in the area of bridge evaluation, repair and rehabilitation is beneficial for both parties involved.

Proceedings of the NATO Advanced Study Institute on Propagation of Correlations in Constrained Systems, Cargese, Corsica, France, July 2-14, 1990

Proceedings of the NATO Advanced Study Institute on Propagation of Correlations in Constrained Systems, Cargese, Corsica, France, July 2-14, 1990

Over eleven years have passed since the last NATO sponsored meeting on Fishing which took the form of a Conference held in Trondheim in 1979. The proceedings contained in this book consist of papers presented in support of an Advanced Study Institute on Operations Research and Management in Fishing held at P6voa de Varzim, Portugal from March 25 to April 7 1990. It was originally intended to use the five themes, Production Functions and Management; Marine Fish Stocks; Fisheries Models; Fish Farming and Miscellaneous. There were no contributions on Fish Processing and the Fish Farming papers were not original. It was also decided to group the papers on Fisheries Models and Marine Fish Stocks together which means the proceedings has four headings: - Opening Session - Production Functions and Management - Marine Fish Stocks and Fisheries Models - Miscellaneous The contributions give a broad and complete overview of historical approaches and of recent trends on research in different sectors of fisheries. Criteria for quota distribution and schemes based on conclusions drawn from models and methods are presented. Surveillance methods are described in relation to species conservation and catch improvement. Different levels of regulatory enforcement are discussed and the implications of new technologies are introduced. Applications of Expert Systems to stock assessment and efficiency improvement in field sampling are presented. Models for fleet dispatch planning and fleet structure appraisal are introduced and procedures for operational capacity evaluation of fishery harbours are considered.

About 20 years ago the emphasis in soil chemistry research switched from studies of problems related to scarcities of plant nutrients to those arising from soil pollutants. The new problems have come about because of the excessive uses of fertilizers, the inputs from farm and industrial wastes, the widespread applications of anthropogenie xenobiotic chemicals, and the deterioration of soil structure resulting from certain modern agriculture practises. The International Society of Soil Science (ISSS) recognized these problems and challenges. A provisional Working Group was set up in 1978 to focus attention on soil colloids with a view to understanding better the interactions wh ich take place at their surfaces. It was recognized that these interactions are fundamental to problems of soil fertility, as weIl as to those of soil pollution. After the group had received the official support of ISSS at its 12th International Congress in New Delhi in 1982 it set as its priority the assembling and evaluation of information, relevant to the soil and environmental sciences, concerning the composition and structure of soil colloids. Prior to that aseries of Position Papers were published in the Bulletin of the International Society of Soil Science (Vol. 61, 1981) outlining the state of knowledge about the composition and properties of soil colloids.