Applied Superconductivity, Metallurgy, and Physics of Titanium Alloys


Book Description

Scope and Purpose Although conductors based on the Al5 intermetallic compound Nb Sn 3 possess desirable high-field superconducting properties, manufacturing and handling difficulties, coupled with the tendency of their critical current densities to degrade rapidly under stress, have generally restricted their use to fairly straightforward, usually small-scale solenoidal-magnet applica tions. Likewise the Al5 compound VGa, which has a wider critical strain 3 window than NbSn but a uniformly lower upper critical field, has not 3 entered widespread service. Strain has been found to have no measurable influence on either the critical fields or the critical current densities of compound superconductors with BI and Cl5 crystal structures, but as yet they are still in the research and development stages. On the other hand, conductors using the binary alloy Ti-Nb or multi component alloys based on it, because of their relative ease of manufacture, excellent mechanical properties, and relatively low strain sensitivities, are now being pressed into service in numerous large-scale devices. Such conductors are being wound into magnets for use in energy storage, energy conversion (i. e. , generators and motors), and high-energy particle detectors and beam-handling magnets. of cold-rolled or drawn Ti-Nb-alloy wire for superconducting The use magnet applications was first proposed in 1961. During the ensuing ten years, while progress was being made in the development of Cu-clad filamentary-Ti-Nb-alloy conductors, Ti-Nb and other Ti-base binary transi tion-metal (TM) alloys were being employed as model systems in the fundamental study of type-II superconductivity.










Polymer Properties at Room and Cryogenic Temperatures


Book Description

Most descriptions of polymers start at room temperature and end at the melting point. This textbook starts at very low temperatures and ends at room temperature. At low temperatures, may processes and relaxations are frozen which allows singular processes or separate relaxations to be studied. At room temperatures, or at the main glass transitions, many processes overlap and the properties are determined by relaxations. At low temperatures, there are temperature ranges with negligible influences by glass transitions. They can be used for investigating so-called basic properties which arise from principles of solid state physics. The chain structure of polymers, however, requires stringent modifications for establishing solid state physics of polymers. Several processes which are specific of polymers, occur only at low temperatures. There are also technological aspects for considering polymers at low temperatures. More and more applications of polymeric materials in low temperature technology appear. Some examples are thermal and electrical insulations, support elements for cryogenic devices, low-loss materials for high frequency equipments. It is hoped that, in addition to the scientific part, a data collection in the appendix may help to apply polymers more intensively in low temperature technology. The author greatly appreciates the contributions by his coworkers of the Kernforschungszentrum Karlsruhe in measurement and discussion of many data presented in the textbook and its appendix. Fruitful disccussions with the colleagues Prof. H. Baur, Prof. S. Hunklinger, Prof. D. Munz and Prof. R.




Cryogenic Process Engineering


Book Description

Cryogenics, a term commonly used to refer to very low temperatures, had its beginning in the latter half of the last century when man learned, for the first time, how to cool objects to a temperature lower than had ever existed na tu rally on the face of the earth. The air we breathe was first liquefied in 1883 by a Polish scientist named Olszewski. Ten years later he and a British scientist, Sir James Dewar, liquefied hydrogen. Helium, the last of the so-caBed permanent gases, was finally liquefied by the Dutch physicist Kamerlingh Onnes in 1908. Thus, by the beginning of the twentieth century the door had been opened to astrange new world of experimentation in which aB substances, except liquid helium, are solids and where the absolute temperature is only a few microdegrees away. However, the point on the temperature scale at which refrigeration in the ordinary sense of the term ends and cryogenics begins has ne ver been weB defined. Most workers in the field have chosen to restrict cryogenics to a tem perature range below -150°C (123 K). This is a reasonable dividing line since the normal boiling points of the more permanent gases, such as helium, hydrogen, neon, nitrogen, oxygen, and air, lie below this temperature, while the more common refrigerants have boiling points that are above this temperature. Cryogenic engineering is concerned with the design and development of low-temperature systems and components.




Modern Gas-Based Temperature and Pressure Measurements


Book Description

Since the beginning of the preparation of this volume, we have been convinced that temperature and pressure measurements should not be separated, particularly in different applications at low temperatures. This belief has made us deeply conscious of the fact that the advanced applications and modern experimental methods of investigation in science and technology need the combination of various professional experiences and approaches. Although the book is divided into two parts (Part I by F. Pavese and Part II by G. F. Molinar), we have tried to correlate low-temperature and low-pressure measurements as much as possible. We hope that our readers will find this book, which contains a large number of experimental and reference data, useful in their effort to solve measurement problems. We are pleased to acknowledge our debt to several persons and wish to express our gratitude to them for their valuable cooperation and help: to our research group colleagues at the Istituto di Metrologia "G. Colonnetti" -IMGC (CNR), without whom the knowledge and the experience we built up during many years could not have been acquired; to G. T. McConville, M. Durieux, and K. Grohmann for revisions of and various suggestions for Part I; to V. E. Bean and C. R. Tilford of NIST and G. T. McConville for revisions of and various suggestions for Part II; and to I. Prinetti of IMGC for many valuable suggestions and careful textual revisions.




Helium Cryogenics


Book Description

At least 10 years have elapsed since a comprehensive monograph concer ned with the broad subject of cryogenics has been published. During this time a considerable quantity of research and development has been carried out in the field of cryogenics. Furthermore, there has been a certain degree of redirection of effort within the field, mostly driven by the variety of new applications, ranging from superconductive magnet systems to micro electronics. Greater emphasis is now being placed on low-temperature cryogenics, particularly that of liquid helium. Until now cryogenic books have provided a broad survey of materials and fluid properties over the entire cryogenic regime, T ::5 150 K. This approach does not allow sufficient detail in any particular area to bring the reader to the current level of understanding in the subject. In addition, the behavior of helium has been lumped with that of other cryogenic fluids, although the properties of helium are quite unique. As a result, a clear relationship has not been established between the fundamental understanding of helium fluids and their potential applications. The present book has been written to fill this void. The approach is to survey the field of cryogenics, specifically as it pertains to helium fluids. This approach is more specialized than that contained in previous cryogenics books. Furthermore, the level of treatment is more advanced and a certain knowledge of fundamental engineering and physics principles has been assumed.




Handbook of Superconductivity


Book Description

This is the last of three volumes of the extensively revised and updated second edition of the Handbook of Superconductivity. The past twenty years have seen rapid progress in superconducting materials, which exhibit one of the most remarkable physical states of matter ever to be discovered. Superconductivity brings quantum mechanics to the scale of the everyday world. Viable applications of superconductors rely fundamentally on an understanding of these intriguing phenomena and the availability of a range of materials with bespoke properties to meet practical needs. While the first volume covers fundamentals and various classes of materials, the second addresses processing of these into various shapes and configurations needed for applications, and ends with chapters on refrigeration methods necessary to attain the superconducting state and the desired performance. This third volume starts with a wide range of methods permitting one to characterize both the materials and various end products of processing. Subsequently, diverse classes of both large scale and electronic applications are described. Volume 3 ends with a glossary relevant to all three volumes. Key Features: Covers the depth and breadth of the field Includes contributions from leading academics and industry professionals across the world Provides hands-on familiarity with the characterization methods and offers descriptions of representative examples of practical applications A comprehensive reference, the handbook is suitable for both graduate students and practitioners in experimental physics, materials science, and multiple engineering disciplines, including electronic and electrical, chemical, mechanical, metallurgy and others.




Safety in the Handling of Cryogenic Fluids


Book Description

The importance of safety in any scientific endeavor is never in question. However, when cryogenic temperatures are involved, safety is especially important. In addition to observing the normal precautions, one must also take into account the variations of physical properties that occur at low temperatures. At these tempera tures, some properties not only exhibit large differences from their normal values but also can vary widely over a small temperature range. Before any cryogenic project is started, a thorough knowledge of the possible hazards is necessary. Only in this way can the safest operation be attained. Over the hundred-year history of cryogenic research, this has been shown to be the case. Keeping this requirement in mind is an essential ingredient in the quest for accident-free work. The past four or five decades have seen a great expansion of cryogenic technology. Cryogenic liquids, such as oxygen, nitrogen, hydrogen, and helium, have become commonly used in a number of different applications and are easily available in any part of the United States and, indeed, almost anywhere in the world. Not only are these liquids available, they have become less expensive and also available in ever larger quantities. As quantities increase, so also do the conse quences of mishaps. The future seems to hold promise of ever larger and more widespread use of the common cryogens. Thus, the importance of safety also increases as time progresses.




Thermodynamic Properties of Cryogenic Fluids


Book Description

Practicing engineers and scientist will benefit from this book's presentation of the most accurate information on the subject. The equations for fifteen important cryogenic fluids are presented in a basic format, accompanied by pressure-enthalpy and temperature-entropy charts and tables of thermodynamic properties. The book is supported by ICMPROPRS - an interactive computer program for the calculation of thermodynamic properties of the cryogenic fluids - that can be downloaded from the World Wide Web.