Radiowave Propagation in Satellite Communications


Book Description

Radiowave Propagation in Communications was written with two basic objec tives: (l) to present an up-to-date review of the major radiowave propagation phenomena which hinder reliable space communications, and (2) to describe how these propagation phenomena affect the design and performance of satellite communications systems. Earth-orbiting satellites are employed extensively for the relay of information in a vast array of telecommunications, meteorological, government, and sci entific applications. Satellite systems rely on the transmission of radiowaves to and from the satellite and are dependent on the propagation characteristics of the transmission path, primarily the earth's atmosphere. Radiowave propagation thus plays a very important part in the design and ultimate performance of space communications systems. This book presents, for the first time, the meshing in a single publication of the fundamentals of radiowave propagation factors with a discussion of the practical consequences of these factors on satellite communications systems. Two major subfie1ds are involved in this book. Radiowave propagation, which is basically applied electromagnetic theory, provides the theory and an alytical tools for the first several chapters. Later chapters then apply propagation effects to the field of electrical engineering involved with satellite communi cations. The material progresses from the essential aspects of radiowave prop agation to the application of practical methods and techniques in the design and performance of satellite communications systems.







Strategy and Methodology for Radioactive Waste Characterization


Book Description

Over the past decade significant progress has been achieved in the development of waste characterization and control procedures and equipment as a direct response to ever-increasing requirements for quality and reliability of information on waste characteristics. Failure in control procedures at any step can have important, adverse consequences and may result in producing waste packages which are not compliant with the waste acceptance criteria for disposal, thereby adversely impacting the repository. The information and guidance included in this publication corresponds to recent achievements and reflects the optimum approaches, thereby reducing the potential for error and enhancing the quality of the end product. -- Publisher's description.




Uranium Enrichment and Nuclear Weapon Proliferation


Book Description

Originally published in 1983, this book presents both the technical and political information necessary to evaluate the emerging threat to world security posed by recent advances in uranium enrichment technology. Uranium enrichment has played a relatively quiet but important role in the history of efforts by a number of nations to acquire nuclear weapons and by a number of others to prevent the proliferation of nuclear weapons. For many years the uranium enrichment industry was dominated by a single method, gaseous diffusion, which was technically complex, extremely capital-intensive, and highly inefficient in its use of energy. As long as this remained true, only the richest and most technically advanced nations could afford to pursue the enrichment route to weapon acquisition. But during the 1970s this situation changed dramatically. Several new and far more accessible enrichment techniques were developed, stimulated largely by the anticipation of a rapidly growing demand for enrichment services by the world-wide nuclear power industry. This proliferation of new techniques, coupled with the subsequent contraction of the commercial market for enriched uranium, has created a situation in which uranium enrichment technology might well become the most important contributor to further nuclear weapon proliferation. Some of the issues addressed in this book are: A technical analysis of the most important enrichment techniques in a form that is relevant to analysis of proliferation risks; A detailed projection of the world demand for uranium enrichment services; A summary and critique of present institutional non-proliferation arrangements in the world enrichment industry, and An identification of the states most likely to pursue the enrichment route to acquisition of nuclear weapons.




To See the Unseen


Book Description

A comprehensive & illuminating history of this little-understood, but surprisingly significant scientific activity. Quite rigorous & systematic in its methodology, the book explores the development of the radar astronomy specialty in the larger community of scientists. More than just discussing the development of this field, however, the author uses planetary radar astronomy as a vehicle for understanding larger issues relative to the planning & execution of "big science" by the Fed. government. Sources, interviews, technical essay, abbreviations, & index.







Time and Frequency: Theory and Fundamentals


Book Description

The document is a tutorial Monograph describing various aspects of time and frequency (T/F). Included are chapters relating to elemental concepts of precise time and frequency; basic principles of quartz oscillators and atomic frequency standards; historical review, recent progress, and current status of atomic frequency standards; promising areas for developing future primary frequency standards; relevance of frequency standards to other areas of metrology including a unified standard concept; statistics of T/F data analysis coupled with the theory and construction of the NBS atomic time scale; an overview of T/F dissemination techniques; and the standards of T/F in the USA. The Monograph addresses both the specialist in the field as well as those desiring basic information about time and frequency. The authors trace the development and scope of T/F technology, its improvement over periods of decades, its status today, and its possible use, applications, and development in days to come.




Vitamin and Mineral Requirements in Human Nutrition


Book Description

In the past 20 years micronutrients have assumed great public health importance and a considerable amount of research has lead to increasing knowledge of their physiological role. Because it is a rapidly developing field, the WHO and FAO convened an Expert Consultation to evaluate the current state of knowledge. It had three main tasks: to review the full scope of vitamin and minerals requirements; to draft and adopt a report which would provide recommended nutrient intakes for vitamins A, C, D, E, and K; the B vitamins; calcium; iron; magnesium; zinc; selenium; and iodine; to identify key issues for future research and make preliminary recommendations for the handbook. This report contains the outcome of the Consultation, combined with up-to-date evidence that has since become available.




Accuracy Requirements and Uncertainties in Radiotherapy


Book Description

Accuracy requirements in radiation oncology have been defined in multiple publications; however, these have been based on differing radiation technologies. In the meantime, the uncertainties in radiation dosimetry reference standards have been reduced and more detailed patient outcome data are available. No comprehensive literature on accuracy and uncertainties in radiotherapy has been published so far. The IAEA has therefore developed a new international consensus document on accuracy requirements and uncertainties in radiation therapy, to promote safer and more effective patient treatments. This publication addresses accuracy and uncertainty issues related to the vast majority of radiotherapy departments including both external beam radiotherapy and brachytherapy. It covers clinical, radiobiological, dosimetric, technical and physical aspects.