In any rotating machinery system, the bearing has traditionally been a crit ical member of the entire system, since it is the component that permits the relative motion between the stationary and moving parts. Depending on the application, a number of different bearing types have been used, such as oil-lubricated hydrodynamic bearings, gas bearings, magnetic suspensions, rolling element bearings, etc. Hydrodynamic bearings can provide any desired load support, but they are limited in stiffness and the associated power loss may be quite large. Gas bearings are used for high-precision applications where the supported loads are relatively light, bearing power losses are very low, and the rotating speeds generally high. For super precision components where no frictional dissipation or bearing power loss can be tolerated, magnetic suspensions are employed; again, the load support requirements are very low. Rolling element bearings have been widely used for those applications that require greater bearing versatility, due to the requirements for high-load and high-stiffness characteristics, while allowing moderate power loss and permitting variable speeds. A study of the dynamic interaction of rolling elements is, therefore, the subject of this text. Texts covering the analysis and design methodology of rolling elements are very limited. Notable works include Analysis of Stresses and Deflections (Jones, 1946, Vols. I and II), Ball and Roller Bearings, Their Theory, Design and Application (Eschmann, Hasbargen, and Weigand, 1958), Ball and Roller Bearing Engineering (Palmgren, 1959, 3rd ed. ), Advanced Bearing Technology (Bisson and Anderson, 1965), and Rolling Bearing Analysis (Harris, 1966)."

"During the last two decades, research on structural optimization became increasingly concerned with two aspects: the application of general numeri- cal methods of optimization to structural design of complex real structures, and the analytical derivation of necessary and sufficient conditions for the optimality of broad classes of comparatively simple and more or less ideal- ized structures. Both kinds of research are important: the first for obvious reasons; the second, because it furnishes information that is useful in testing the validity, accuracy and convergence of numerical methods and in assess- ing the efficiency of practical designs. " (Prager and Rozvany, 1977a) The unexpected death of William Prager in March 1980 marked, in a sense, the end of an era in structural mechanics, but his legacy of ideas will re- main a source of inspiration for generations of researchers to come. Since his nominal retirement in the early seventies, Professor and Mrs. Prager lived in Savognin, an isolated alpine village and ski resort surrounded by some of Switzerland's highest mountains. It was there that the author's close as- sociation with Prager developed through annual pilgrimages from Australia and lengthy discussions which pivoted on Prager's favourite topic of struc- tural optimization. These exchanges took place in the picturesque setting of Graubunden, on the terrace of an alpine restaurant overlooking snow-capped peaks, on ski-lifts or mountain walks, or during evening meals in the cosy hotels of Savognin, Parsonz and Riom.

The great bulk of the literature on aeroelasticity is devoted to linear models. The oretical work relies heavily on linear mathematical concepts, and experimental results are commonly interpreted by assuming that the physical model behaves in a linear manner. Nevertheless, significant work has been done in nonlinear aero elasticity, and one may expect this trend to accelerate for several reasons: our ability to compute has increased at an astonishing rate; as linear concepts have been assimilated widely, there is a natural increase in interest in the foundations of nonlinear modeling; and, finally, some phenomena long recognized to be of interest, but beyond the effective range of linear models, are now known to be essentially nonlinear in nature. In this volume, an exhaustive review of the literature is not attempted. Rather the emphasis is on fundamental ideas and a representative selection of problems. Despite obvious successes in research on problems of aeroelasticity and the existence of a broad literature, including a number of excellent monographs, up to now little attention has been devoted to a general nonlinear theory of interac tion. For the most part nonlinearity has been considered either solely in the description of the behavior of a shell or in the description of the motion of a gas."

''It is true that "Nothing is more practical than a theory" Provided - however - That the assumptions on which the theory is founded Are well understood. - But, indeed, engineering experience shows that "Nothing can be more disastrous than a theory When applied to a real problem Outside of the practicailimits of the assumptions made," Because of an homonymous identity With the problem under consideration. " (J. T. P. ) The primary objective of this work is to present the theories of analytical and optical isodynes and the related measurement procedures in a manner com patible with the modem scientific methodology and with the requirements of modem technology pertaining to the usefulness of the stress analysis proce dures. The selected examples illustrate some major theses of this work and demonstrate the particular efficiency of the isodyne methods in solving the technologically important problems in fracture mechanics and mechanics of composite structures including new materials. To satisfy this objective it was necessary to depart from the common practice of presenting theories and techniques of experimental methods as a compatible system of equations and procedures without mentioning the tacitly accepted assumptions and their influence on the theoretical admissibility of analytical expressions and the reliability of the experimental or analytical results. It was necessary to design a more general frame of reference which could allow to assess the scientific correctness of isodyne methods and the reliability of experimental results."

This book is about aerospace sensors, their principles of operation, and their typical advantages, shortcomings, and vulnerabilities. They are described in the framework of the subsystems where they function and in accordance with the flight mission they are designed to serve. The book is intended for students at the advanced undergraduate or graduate level and for research engineers who need to acquire this kind of knowledge. An effort has been made to explain, within a uniform framework of mathematical modeling, the physics upon which a certain sensor concept is based, its construction, its dynamics, and its error sources and their corresponding mathematical models. Equipped with such knowledge and understanding, the student or research engineer should be able to get involved in research and development activities of guidance, control, and navigation systems and to contribute to the initiation of novel ideas in the aerospace sensor field. As a designer and systems engineer, he should be able to correctly interpret the various items in a technical data list and thus to interact intelligently with manufacturers' representatives and other members of an R&D team. Much of the text has evolved from undergraduate and graduate courses given by the author during the past seventeen years at the Department of Aerospace Engineering at the Technion- Israel Institute of Technology and from his earlier research and development experience in flight control, guidance, navigation, and avionics at the Ministry of Defense Central Research Institute.

The Joint Institute for Aeronautics and Acoustics at Stanford University was established in October 1973 to provide an academic environment for long-term cooperative research between Stanford and NASA Ames Research Center. Since its establishment, the In stitute has wnducted theoretical and experimental work in the areas of aerodynamics, acoustics, fluid mechanics, flight dynamics, guid ance and control, and human factors. This research has involved Stanford faculty, research associates, graduate students, and many distinguished visitors in collaborative efforts with the research staff of NASA Ames Research Center. The occasion of the Institute's tenth anniversary was used to reflect back on where that research has brought us, and to consider where our endeavors should be directed next. Thus, an International Symposium was held to review recent advances in the fields relevant to the activities of the Institute and to discuss the areas of research to be undertaken in the future. This anniversary was also chosen a.."1 an opportunity to honor one of the Institute's founders and its di rector, Professor Krishnamurty Karamcheti. It has been his creative inspiration that has provided the ideal research environment at the Joint Institute. The International Symposium on Recent Advances in Aero dynamics and Aconstics was held at Stanford University, Stanford, California, U.S.A., August 22-26, 198: . Thirty-five distinguished scientists were invited to present a comprehensive review on the fol lowing subject areas: unsteady aerodynamics, jets and shear layers, V /STOL aircraft aerodynamics, rotor dynamics and aerodynamics, ."

The author provides new insights into the relationship between transport and the environment, the role of technology and the meaning of the concept of sustainable development for the transport sector. Special attention is given to the relationship between technological progress and policy. The different theoretical approaches are combined to create a strategy for R&D and the implementation of mega-technological innovations. The empirical part deals with two specific cases: Maglev technology and fuel-cell technology for transport purposes. Taking into account the new theoretical insights and the empirical findings, the author presents a synthesis and draws conclusions which are important for researchers and professionals in transportation, environmental sciences and related fields.

This book is an introduction to the elementary technology of automobile suspensions. Inevitably steering geometry must be included in the text, since the dynamic steering behaviour, road-holding and cornering behaviour are all influenced by the suspension design. Steering mechanisms and steering components are not covered in this book. This is not a mathematical treatise, but only a fool or a genius would attempt to design a motor vehicle without mathematics. The mathematics used in this book should present no problem to a first-year university student. SI units have been used in general, but for the benefit of those not familiar with them we have included in brackets, in many cases, the equivalent values in Imperial units. Many engineers regard the Pascal as an impractical unit of pressure. The author has therefore expressed pressures in bars (1 bar = 105Pa). A deviation from SI units is the use of degrees and minutes, instead of radians, to express camber, castor, roll angles, etc. This is still common practice in the motor industry. No attempt has been made to make any stress calculations on suspension components. The automobile engineering student will have access to other textbooks on such subjects as strength of materials and theory of structures.

Dealing with a wide range of topics and covering different aspects of current importance in ATM, the papers place particular emphasis on automation and application of mathematical models and computational algorithms for ATM systems. The volume thus offers readers a summary of recent progress in such important areas as new operational concepts for automated ATM, evolution of traffic characteristics, ground-holding algorithms, ATC simulation facilities and a number of other aspects of ATC flow management.

It is difficult to do justice to fracture mechanics in a textbook, for the subject encompasses so many disciplines. A general survey of the field would serve no purpose other than give a collection of references. The present book by Professor E. E. Gdoutos is refreshing because it does not fall into the esoteric tradition of outlining equations and results. Basic ideas and underlying principles are clearly explained as to how they are used in application. The presentations are concise and each topic can be understood by advanced undergraduates in material science and continuum mechanics. The book is highly recommended not only as a text in fracture mechanics but also as a reference to those interested in the general aspects of failure analysis. In addition to providing an in-depth review of the analytical methods for evaluating the fundamental quantities used in linear elastic fracture mechanics, various criteria are discussed re: O. ecting their limitations and applications. Par ticular emphases are given to predicting crack initiation, subcritical growth and the onset of rapid fracture from a single criterion. Those models in which it is assumed that the crack extends from tip to tip rely on the specific surface energy concept. The differences in the global and energy states before and after crack extension were associated with the energy required to create a unit area of crack surface. Applications were limited by the requirement of self-similar crack growth."

There is a growing social interest in developing vision-based vehicle guidance systems for improving traffic safety and efficiency and the environment. Ex amples of vision-based vehicle guidance systems include collision warning systems, steering control systems for tracking painted lane marks, and speed control systems for preventing rear-end collisions. Like other guidance systems for aircraft and trains, these systems are ex pected to increase traffic safety significantly. For example, safety improve ments of aircraft landing processes after the introduction of automatic guidance systems have been reported to be 100 times better than prior to installment. Although the safety of human lives is beyond price, the cost for automatic guidance could be compensated by decreased insurance costs. It is becoming more important to increase traffic safety by decreasing the human driver's load in our society, especially with an increasing population of senior people who continue to drive. The second potential social benefit is the improvement of traffic efficiency by decreasing the spacing between vehicles without sacrificing safety. It is reported, for example, that four times the efficiency is expected if the spacing between cars is controlled automatically at 90 cm with a speed of 100 kmjh compared to today's typical manual driving. Although there are a lot of tech nical, psychological, and social issues to be solved before realizing the high density jhigh-speed traffic systems described here, highly efficient highways are becoming more important because of increasing traffic congestion."

Gone are the days when mobility was nearly always a question of having a vehicle. Today the issue of road capacity is becoming ever more pressing. Even the safest, most comfortable and 100% emissions-free vehicle is only of limited use if it is stuck in a traffic jam. Mobility is a key human need and an important factor in the economy. It is a matter of logic that a com pany like DaimlerChrysler should make every endeavor to safeguard mo bility, thereby fulfilling humanity's economic, social and environmental needs. Nonetheless, traffic and mobility problems are the inevitable result of a concentration of people and markets. Bombay, Lagos, Shanghai, Jakarta, Sao Paulo, Cairo, Mexico City - virtually half of the world's population is urban-based, and the majority live in the metropolitan regions of the Third World. The mega-cities in the so-called developing nations are facing a dramatic increase in traffic levels. Gridlock looms on the horizon. Should traffic-choked streets become a permanent and daily occurrence, economic development will be held in check and pollution will spiral."

The series Advances in Industrial Control aims to report and encourage technology transfer in control engineering. The rapid development of control technology impacts all areas of the control discipline. New theory, new controllers, actuators, sensors, new industrial processes, computer methods, new applications, new philosophies, . . . . , new challenges. Much of this deVelopment work resides in industrial reports, feasibility study papers and the reports of advanced collaborative projects. The series offers an opportunity for researchers to present an extended exposition of such new work in all aspects of industrial control for wider and rapid dissemination. The high performance control systems applications in aerospace and astronautics almost have a tradition of exploiting the most advanced control theoretical developments first. The optimal control and ffitering paradigm associated with the names of Kalman, Bucy, Anderson and Moore found application in the astronautics of the 1960'S and 1970'S. At the beginning of the 1980'S, control theory moved on to robustness, singular values and mu-analysis. This new work was associated with the names of Zames, Doyle, Glover, Balas among others. The Advances in Industrial Control monograph series have published several volumes over the years which have archived the applications experience garnered from applying robust control to the aerospace sector problems. Rick Lind and Marty Brenner add to this set with their volume on robust aeroservoelastic stability. This volume reports the application of the structured singular value to aeroelastic and aeroservoelastic aerospace problems.

Most fluid flows of practical importance are fully three-dimensional, so the non-linear instability properties of three-dimensional flows are of particular interest. In some cases the three-dimensionality may have been caused by a finite amplitude disturbance whilst, more usually, the unperturbed state is three-dimensional. Practical applications where transition is thought to be associated with non-linearity in a three- dimensional flow arise, for example, in aerodynamics (swept wings, engine nacelles, etc.), turbines and aortic blood flow. Here inviscid `cross-flow' disturbances as well as Tollmien-Schlichting and Goertler vortices can all occur simultaneously and their mutual non-linear behaviour must be understood if transition is to be predicted. The non-linear interactions are so complex that usually fully numerical or combined asymptotic/numerical methods must be used. Moreover, in view of the complexity of the instability processes, there is also a growing need for detailed and accurate experimental information. Carefully conducted tests allow us to identify those elements of a particular problem which are dominant. This assists in both the formulation of a relevant theoretical problem and the subsequent physical validation of predictions. It should be noted that the demands made upon the skills of the experimentalist are high and that the tests can be extremely sophisticated - often making use of the latest developments in flow diagnostic techniques, automated high speed data gathering, data analysis, fast processing and presentation.

Includes MATLAB-based computational and design algorithms utilizing the "Linear Systems Toolkit." All results and case studies presented in both the continuous- and discrete-time settings.

The series Advances in Industrial Control aims to report and encourage technology transfer in control engineering. The rapid development of control technology impacts all areas of the control discipline. New theory, new controllers, actuators, sensors, new industrial processes, computer methods, new applications, new philosophies, .... , new challenges. Much of this development work resides in industrial reports, feasibility study papers and the reports of advanced collaborative projects. The series offers an opportunity for researchers to present an extended exposition of such new work in all aspects of industrial control for wider and rapid dissemination. Micro-technology and modern communications technology are revolutionising many aspects of our daily lives and so it is not surprising that it is impacting societal transportation systems whether our highways, airways, seaways or railways. The Advances in Industrial Control series reported on these developments for long haul railway systems in a monograph by Howlett and Pudney (ISBN 3-S40-19990-X, 1995). Now it is the turn of transportation in a contribution from Pushkin Kachroo and Kaan Ozbay. The authors viewpoint is that this new set of transportation problems are control problems and that control engineers should be highly active in this field. Their volume covers all the aspects of modelling, problem formulation, and applies various control methodologies to solve the control problems formulated.

Turbulence is a dangerous topic which is often at the origin of serious fights in the scientific meetings devoted to it since it represents extremely different points of view, all of which have in common their complexity, as well as an inability to solve the problem. It is even difficult to agree on what exactly is the problem to be solved. Extremely schematically, two opposing points of view have been advocated during these last ten years: the first one is "statistical", and tries to model the evolution of averaged quantities of the flow. This com has followed the glorious trail of Taylor and Kolmogorov, munity, which believes in the phenomenology of cascades, and strongly disputes the possibility of any coherence or order associated to turbulence. On the other bank of the river stands the "coherence among chaos" community, which considers turbulence from a purely deterministic po int of view, by studying either the behaviour of dynamical systems, or the stability of flows in various situations. To this community are also associated the experimentalists who seek to identify coherent structures in shear flows.

The Joint Institute for Aeronautics and Acoustics at Stanford University was established in October 1973 to provide an academic environment for long-term cooperative research between Stanford and NASA Ames Research Center. Since its establishment, the Institute has conducted theoretical and experimental work in the areas of aerodynamics, acoustics, fluid mechanics, flight dynamics, guidance and control, and human factors. This research has involved Stanford faculty, research associates, graduate students, and many distinguished visitors in collaborative efforts with the research staff of NASA Ames Research Center. The occasion of the Institute's tenth anniversary was used to reflect back on where that research has brought us, and to consider where our endeavors should be directed next. Thus, an International Symposium was held to review recent advances in the fields relevant to the activities of the Institute and to discuss the areas of research to be undertaken in the future. This anniversary was also chosen as an opportunity to honor one of the Institute's founders and its director, Professor Krishnamurty Karamcheti. It has been his crea tive inspiration that has provided the ideal research environment at the Joint Institute."

"Are there common phenomena and laws in the dynamic behavior of granular materials, traffic, and socio-economic systems?" The answers given at the international workshop "Traffic and Granular Flow '99" are presented in this volume. From a physical standpoint, all these systems can be treated as (self)-driven many-particle systems with strong fluctuations, showing multistability, phase transitions, non-linear waves, etc. The great interest in these systems is due to several unexpected new discoveries and their practical relevance for solving some fundamental problems of today's societies. This includes intelligent measures for traffic flow optimization and methods from "econophysics" for stabilizing (stock) markets.

The aerodynamics of aircraft at high angles of attack is a subject which is being pursued diligently, because the modern agile fighter aircraft and many of the current generation of missiles must perform well at very high incidence, near and beyond stall. However, a comprehensive presentation of the methods and results applicable to the studies of the complex aerodynamics at high angle of attack has not been covered in monographs or textbooks. This book is not the usual textbook in that it goes beyond just presenting the basic theoretical and experimental know-how, since it contains reference material to practical calculation methods and technical and experimental results which can be useful to the practicing aerospace engineers and scientists. It can certainly be used as a text and reference book for graduate courses on subjects related to high angles of attack aerodynamics and for topics related to three-dimensional separation in viscous flow courses. In addition, the book is addressed to the aerodynamicist interested in a comprehensive reference to methods of analysis and computations of high angle of attack flow phenomena and is written for the aerospace scientist and engineer who is familiar with the basic concepts of viscous and inviscid flows and with computational methods used in fluid dynamics.

Advances for In-Vehicle and Mobile Systems: Challenges for International Standards is organized to bring together the most active scholars working on the latest techniques, standards, and emerging deployment on "living in the age of wireless communications and smart vehicular systems." The objective is to incorporate speech, dialog, video, image, vehicular sensory data, and wireless communication modalities to model the total behavior of the driver and use that model towards personalization of the vehicle to provide a more comfortable and safer driving experience. The format of this work centers on four themes: driver and driving environment recognition, telecommunication applications, noise reduction, and dialog in vehicles.Advances for In-Vehicle and Mobile Systems: Challenges for International Standards, is appropriate for researchers, engineers, and professionals working in signal processing technologies, next generation vehicle design, and networks for mobile platforms.

The conventional approach to through-life-support for aircraft structures can be divided into the following phases: (i) detection of defects, (ii) diagnosis of their nature and significance, (iii) forecasting future behaviour-prognosis, and (iv) pre scription and implementation of remedial measures including repairs. Considerable scientific effort has been devoted to developing the science and technology base for the first three phases. Of particular note is the development of fracture mechanics as a major analytical tool for metals, for predicting residual strength in the presence of cracks ( damage tolerance) and rate of crack propagation under service loading. Intensive effort is currently being devoted to developing similar approaches for fibre composite structures, particularly to assess damage tolerance and durability in the presence of delamination damage. Until recently there has been no major attempt to develop a science and tech nology base for the last phase, particularly with respect to the development of repairs. Approaches are required which will allow assessment of the type and magnitude of defects amenable to repair and the influence of the repair on the stress intensity factor (or some related parameter). Approaches are also required for the development and design of optimum repairs and for assessment of their durability."

Experts discuss how to repair, rehabilitate and modernize the transportation infrastructure in emerging Central Europe. The focus is on applying modern engineering technologies and management decision-making technologies to solve common and regional environmental issues in ground transportation, with emphasis on roads and bridges. The book includes situation, position and technical papers and state-of-the-art presentations from scientific and engineering experts as well as from government agency officials responsible for national and regional transport. Concise, cogent recommendations are presented. The reader is provided with current information on related environmental and transportation issues. Experts and lay readers will benefit from the information on economic, social, and political aspects.

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