Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages :

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Author: David R. Schryer
Publisher:
ISBN:
Category : Molybdenum
Languages : en
Pages : 52

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Book Description
A theoretical and experimental investigation of the oxidation of molybdenum to molybdenum trioxide at temperatures at which the trioxide is volatile has been carried out. A rate equation has been derived which includes the effects of mass-transfer parameters as well chemical parameters and is applicable to any situation for which a mass-transfer coefficient can be obtained. The derived equation has been applied to previously reported rate data taken under laboratory conditions using air and oxygen-helium mix-reported rate data taken under laboratory conditions using air and oxygen-helium mixtures flowing at low subsonic velocities, and a set of values for the activation energy of the oxidation of molybdenum has been obtained. The average of these values is 8.51 x 107 J-(kg-mole)−1 (20.3 kcal-(g-mole)−1) with a standard deviation of 2.1 percent. In addition, 32 molybdenum hemisphere-cylinder specimens have been oxidized in a Mach 2.1 heated airstream at a free-stream stagnation pressure of 1.07 x 106 N-m-−2 (10.5 atm) and free-stream stagnation temperatures from 1765°K to 2120°K. The stagnation-point surface temperature and recession rate were determined for each of the specimens. The observed recession rates were compared with the corresponding values predicted theoretically by the derived rate equation and agreement within a factor of about 2 was obtained for most specimens. However, a few specimens ignited, exhibiting recession rates much greater than those predicted theoretically. The high recession rates associated with ignition were found to be the result of a sharp rise in surface temperature which caused some melting of the specimens in addition to their normal oxidation.

Author: Vincent David Barth
Publisher:
ISBN:
Category : Tungsten
Languages : en
Pages : 192

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Book Description
The report presents a detailed review of available information on the oxidation of W and its alloys. W is relatively inert below 700 C. As the temperature is increased above this level, however, oxidation becomes progressively more rapid, reaching catastrophic rates at temperatures around 1200 C and above. Various theories for the mechanism and rates of W oxidation at different temperatures are reviewed, and the effect of pressure and water vapor on the stability of W oxides is discussed in detail. The elevatedtemperature reactions of W with other materials, such as refractory oxides, and with gases other than oxygen also are covered. Information on the protection of W by alloying and coating is included. (Author).

Author: United States. Public Health Service. Office of the Surgeon General
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 728

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Book Description
This report considers the biological and behavioral mechanisms that may underlie the pathogenicity of tobacco smoke. Many Surgeon General's reports have considered research findings on mechanisms in assessing the biological plausibility of associations observed in epidemiologic studies. Mechanisms of disease are important because they may provide plausibility, which is one of the guideline criteria for assessing evidence on causation. This report specifically reviews the evidence on the potential mechanisms by which smoking causes diseases and considers whether a mechanism is likely to be operative in the production of human disease by tobacco smoke. This evidence is relevant to understanding how smoking causes disease, to identifying those who may be particularly susceptible, and to assessing the potential risks of tobacco products.

Author: D. Maugis
Publisher: Springer Science & Business Media
ISBN: 3662041251
Category : Science
Languages : en
Pages : 426

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Book Description
This book, based on the analogy between contact mechanics and fracture mechanics proposed by the author twenty years ago, starts with a treatment of the surface energy and tension of solids and surface thermodynamics. The essential concepts of fracture mechanics are presented with emphasis on the thermodynamic aspects. Readers will find complete analytical results and detailed calculations for cracks submitted to pressure distributions and the Dugdale model. Contact mechanics and the contact and adherence of rough solids are also covered.

Author: Perrin Walker
Publisher: CRC Press
ISBN: 9781439822531
Category : Science
Languages : en
Pages : 1434

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Book Description
This publication presents cleaning and etching solutions, their applications, and results on inorganic materials. It is a comprehensive collection of etching and cleaning solutions in a single source. Chemical formulas are presented in one of three standard formats - general, electrolytic or ionized gas formats - to insure inclusion of all necessary operational data as shown in references that accompany each numbered formula. The book describes other applications of specific solutions, including their use on other metals or metallic compounds. Physical properties, association of natural and man-made minerals, and materials are shown in relationship to crystal structure, special processing techniques and solid state devices and assemblies fabricated. This publication also presents a number of organic materials which are widely used in handling and general processing...waxes, plastics, and lacquers for example. It is useful to individuals involved in study, development, and processing of metals and metallic compounds. It is invaluable for readers from the college level to industrial R & D and full-scale device fabrication, testing and sales. Scientific disciplines, work areas and individuals with great interest include: chemistry, physics, metallurgy, geology, solid state, ceramic and glass, research libraries, individuals dealing with chemical processing of inorganic materials, societies and schools.

Author: A.K. Suri
Publisher: Routledge
ISBN: 1351448978
Category : Science
Languages : en
Pages : 272

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Book Description
The growth and development witnessed today in modern science, engineering, and technology owes a heavy debt to the rare, refractory, and reactive metals group, of which niobium is a member. Extractive Metallurgy of Niobium presents a vivid account of the metal through its comprehensive discussions of properties and applications, resources and resource processing, chemical processing and compound preparation, metal extraction, and refining and consolidation. Typical flow sheets adopted in some leading niobium-producing countries for the beneficiation of various niobium sources are presented, and various chemical processes for producing pure forms of niobium intermediates such as chloride, fluoride, and oxide are discussed. The book also explains how to liberate the metal from its intermediates and describes the physico-chemical principles involved. It is an excellent reference for chemical metallurgists, hydrometallurgists, extraction and process metallurgists, and minerals processors. It is also valuable to a wide variety of scientists, engineers, technologists, and students interested in the topic.

Author: Leo Aloysius Wall
Publisher:
ISBN:
Category : Chemistry, Organic
Languages : en
Pages : 204

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Author: Bjorn Mysen
Publisher: Elsevier
ISBN: 0444637095
Category : Science
Languages : en
Pages : 722

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Book Description
Silicate Glasses and Melts, Second Edition describes the structure-property-composition relationships for silicate glasses and melts from a geological and industrial perspective. Updated sections include (i) characterization of silicate melt and COHN fluid structure (with and without dissolved silicate components) with pressure, temperature, and redox conditions and responses of structural variables to chemical composition, (ii) determination of solubility and solution mechanisms of COHN volatiles in silicate melts and minerals and of solubility and solution mechanisms of silicate components in COHN fluids, and (iii) effects of very high pressure on structure and properties of melts and glasses. This new book is an essential resource for researchers in a number of fields, including geology, geophysics, geoscience, volcanology, material science, glass science, petrology and mineralogy. - Brings together multidisciplinary research scattered across the scientific literature into one reference, with a focus on silicate melts and their application to natural systems - Emphasizes linking melt properties to melt structure - Includes a discussion of the pros and cons of the use of glass as a proxy for melt structure and properties - Written by highly regarded experts in the field who, among other honors, were the 2006 recipients of the prestigious G.W. Morey award of the American Ceramic Society

Author: John B. Wachtman
Publisher: John Wiley & Sons
ISBN: 9780470451502
Category : Technology & Engineering
Languages : en
Pages : 496

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Book Description
A Comprehensive and Self-Contained Treatment of the Theory and Practical Applications of Ceramic Materials When failure occurs in ceramic materials, it is often catastrophic, instantaneous, and total. Now in its Second Edition, this important book arms readers with a thorough and accurate understanding of the causes of these failures and how to design ceramics for failure avoidance. It systematically covers: Stress and strain Types of mechanical behavior Strength of defect-free solids Linear elastic fracture mechanics Measurements of elasticity, strength, and fracture toughness Subcritical crack propagation Toughening mechanisms in ceramics Effects of microstructure on toughness and strength Cyclic fatigue of ceramics Thermal stress and thermal shock in ceramics Fractography Dislocation and plastic deformation in ceramics Creep and superplasticity of ceramics Creep rupture at high temperatures and safe life design Hardness and wear And more While maintaining the first edition's reputation for being an indispensable professional resource, this new edition has been updated with sketches, explanations, figures, tables, summaries, and problem sets to make it more student-friendly as a textbook in undergraduate and graduate courses on the mechanical properties of ceramics.