Cryocoolers


Book Description

This book serves as an introduction to cryocooler technology and describes the principle applications of cryocoolers across a broad range of fields. It covers the specific requirements of these applications, and describes how the advantages and disadvantages of different cryocooler systems are taken into consideration. For example, Stirling coolers tend to be used only in space applications because of their high coefficient of performance, low weight and proven reliability, whilst Gifford-McMahon coolers are used for ground applications, such as in cryopumps and MRI shield cooling applications. Joule-Thomson cryocoolers are used in missile technology because of the fast cool down requirements. The cryocooler field is fast developing and the number of applications are growing because of the increasing costs of the cryogens such as Helium and Neon. The first chapter of the book introduces the different types of cryocoolers, their classification, working principles, and their design aspects, and briefly mentions some of the applications of these systems. This introductory chapter is followed by a number of contributions from prominent international researchers, each describing a specific field of application, the cooling requirements and the cryocooler systems employed. These areas of application include gas liquefaction, space technology, medical science, dilution refrigerators, missile systems, and physics research including particle accelerators. Each chapter describes the cooling requirements based on the end use, the approximate cooling load calculations, the criteria for cryocooler selection, the arrangement for cryocooler placement, the connection of the cooler to the object to be cooled, and includes genuine case studies. Intended primarily for researchers working on cryocoolers, the book will also serve as an introduction to cryocooler technology for students, and a useful reference for those using cryocooler systems in any area of application.




Sixteenth Marcel Grossmann Meeting, The: On Recent Developments In Theoretical And Experimental General Relativity, Astrophysics, And Relativistic Field Theories - Proceedings Of The Mg16 Meeting On General Relativity (In 4 Volumes)


Book Description

The proceedings of MG16 give a broad view of all aspects of gravitational physics and astrophysics, from mathematical issues to recent observations and experiments. The scientific program of the meeting included 46 plenary presentations, 3 public lectures, 5 round tables and 81 parallel sessions arranged during the intense six-day online meeting. All talks were recorded and are available on the ICRANet YouTube channel at the following link: www.icranet.org/video_mg16.These proceedings are a representative sample of the very many contributions made at the meeting. They contain 383 papers, among which 14 come from the plenary sessions.The material represented in these proceedings cover the following topics: accretion, active galactic nuclei, alternative theories of gravity, black holes (theory, observations and experiments), binaries, boson stars, cosmic microwave background, cosmic strings, dark energy and large scale structure, dark matter, education, exact solutions, early universe, fundamental interactions and stellar evolution, fast transients, gravitational waves, high energy physics, history of relativity, neutron stars, precision tests, quantum gravity, strong fields, and white dwarf; all of them represented by a large number of contributions.The online e-proceedings are published in an open access format.




Submillimetre Studies of Prestellar and Starless Cores in the Ophiuchus, Taurus and Cepheus Molecular Clouds


Book Description

This thesis presents studies of the starless core populations of three nearby molecular clouds made as part of the James Clerk Maxwell Telescope Gould Belt Survey. These studies combine observations made using the SCUBA-2 submillimetre camera with data from several other instruments, including the Herschel Space Observatory, to identify and characterise starless cores in the Ophiuchus, Taurus and Cepheus molecular clouds. The temperatures, masses and stability against collapse of the starless cores are measured, the latter through detailed virial analysis, including a determination of the external pressure on the cores. The book illustrates core stability on the “virial plane”, in which core stability is plotted against core confinement mode, showing that starless cores are typically confined by external pressure rather than self-gravity. It also presents an analytical model of the evolution of starless cores in the “virial plane”, demonstrating that a pressure-confined starless core may evolve due to virial stability rather than gravitational collapse, which means that a core can only be definitively considered to be prestellar if it is gravitationally bound.




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.