Download or read book Aluminosilicates haute pression et haute temp rature written by Isabelle Daniel and published by . This book was released on 1995 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'étude des propriétés des minéraux du manteau terrestre in situ nécessite de reproduire expérimentalement des conditions de pression allant de 3 à 130 GPa ainsi que des températures comprises entre 1000 et 4000 K environ. Nous avons développé des dispositifs expérimentaux permettant d'étudier le comportement de quelques phases aluminosilicatées par spectroscopie Raman à haute pression et/ou haute température. L'étude de la cristallisation de l'anorthite in situ à haute tempàrature a révélé l'existence d'un nouveau polymorphe métastable qui cristallise à partir du liquide CaAl2Si2O8 à 1545 K ou bien à partir de la phase pseudo-hexagonale à 1050 k. Il fond à 1700 ± 10 K. A haute pression, l'anorthite présente une transition polymorphique de premier ordre, réversible, à 10 GPa. A 16 GPa, elle perd son caractère cristallin et devient amorphe. La pression d'amorphisation dépend étroitement du degré d'hydrostaticité des conditions expérimentales. Quand les conditions deviennent moins hydrostatiques, la pression d'amorphisation chute de 16 GPa à 10 GPa. Par ailleurs, nous avons étudié le comportement des verres de composition CaAl2Si2O8, NaAlSi3O8 et CaAl2O4 en fonction de la température jusqu'a 2000 K. L'extraction du spectre Raman de premier ordre corrigé de toute dépendance en température et en fréquence permet d'identifier les changements de configurations microscopiques qui se produisent à la transition vitreuse. Afin de déterminer leur nature, nous avons comparé les changements qui se produisent dans les liquides à haute température avec ceux de haute pression. Dans le cadre de CaAl2O4, la coordinence de Al et O augmentent au delà de Tg, les nouvelles figures spectrales sont liées à une augmentation de la coordinence de O
Download or read book Thermodynamic Data written by Surendra K. Saxena and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the rapid development of fast processors, the power of a mini-super computer now exists in a lap-top box. Quite sophisticated techniques are be coming accessible to geoscientists, thus making disciplinary boundaries fade. Chemists and physicists are no longer shying away from computational mineral ogical and material science problems "too complicated to handle." Geoscientists are willing to delve into quantitative physico-chemical methods and open those "black boxes" they had shunned for several decades but with which had learned to live. I am proud to present yet another volume in this series which is designed to break the disciplinary boundaries and bring the geoscientists closer to their chemist and physicist colleagues in achieving a common goal. This volume is the result of an international collaboration among many physical geochemists (chemists, physicists, and geologists) aiming to understand the nature of material. The book has one common theme: namely, how to determine quantitatively through theory the physico-chemical parameters of the state of a solid or fluid.
Download or read book High Temperature Levitated Materials written by David L. Price and published by Cambridge University Press. This book was released on 2010-05-06 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the major experimental difficulties in studying materials at extreme temperatures is unwanted contamination of the sample through contact with the container. This can be avoided by suspending the sample through levitation. This technique also makes metastable states of matter accessible, opening up new avenues of scientific enquiry, as well as possible new materials for technological applications. This book describes several methods of levitation, the most important being aerodynamic, electromagnetic and electrostatic. It summarizes the state-of-the-art of the measurement of structural, dynamic and physical properties with levitation techniques, the considerable progress made in this field in the past two decades, and prospects for the future. It also explores the concepts behind the experiments and associated theoretical ideas. Aimed at researchers in physics, physical chemistry and materials science, the book is also of interest to professionals working in high-temperature materials processing and the aerospace industry.
Download or read book Spectroscopic Methods in Mineralogy and Material Sciences written by Grant Henderson and published by Walter de Gruyter GmbH & Co KG. This book was released on 2014-11-21 with total page 820 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spectroscopic Methods in Mineralogy and Material Science covers significant advances in the technological aspects and applications of spectroscopic and microscopic techniques used in the Earth and Materials Sciences. The current volume compliments the now classic Volume 18, Spectroscopic Methods in Mineralogy and Geology, which became an essential resource to many scientists and educators for the past two decades. This volume updates techniques covered in Volume 18, and introduces new techniques available for probing the secrets of Earth materials, such as X-ray Raman and Brillouin spectroscopy. Other important topics including Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM) are also covered.
Download or read book Advances in Interpretation of Geological Processes written by Maria Iole Spalla and published by Geological Society of London. This book was released on 2010 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: Iterative comparison of analytical results and natural observations with predictions of numerical models improves interpretation of geological processes. Further refinements derive from wide-angle comparison of results from various scales of study. In this volume, advances from field, laboratory and modelling approaches to tectonic evolution - from the lithosphere to the rock scale - are compared. Constructive use is made of apparently discrepant or non-consistent results from analytical or methodological approaches in processing field or laboratory data, P-T estimates, absolute or relative age determinations of tectonic events, tectonic unit size in crustal-scale deformation, grain-scale deformation processes, various modelling approaches, and numerical techniques. Advances in geodynamic modelling critically depend on new insights into grain- and subgrain-scale deformation processes. Conversely, quantitative models help to identify which rheological laws and pa-rameters exert the strongest control on multi-scale deformation up to lithosphere and upper mantle scale
Download or read book Physics and Chemistry of Glasses written by and published by . This book was released on 2005 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Volatiles in Magmas written by Michael R. Carroll and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 30 of Reviews in Mineralogy introduces in understanding the behavior of magmatic volatiles and their influence on a wide variety of geological phenomena; in doing this it also becomes apparent that there remain many questions outstanding. The range of topics we have tried to cover is broad, going from atomisticscale aspects of volatile solubility mechanisms and attendant effects on melt physical properties, to the chemistry of volcanic gases and the concentrations of volatiles in magmas, to the global geochemical cycles of volatiles. The reader should quickly see that much progress has been made since Bowen voiced his concerns about Maxwell demons, but like much scientific progress, answers to old questions have prompted even greater numbers of new questions. The Voltiles in Magmas course was organized and transpired at the Napa Valley Sheraton Hotel in California, December 2-4, 1994, just prior to the Fall Meetings of the American Geophysical Union in San Francisco.
Download or read book Bulletin de Min ralogie written by and published by . This book was released on 1978 with total page 878 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cristallochimie des l ments traces dans les phases du manteau terrestre written by Gilles Quérel and published by . This book was released on 1998 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: La connaissance des coefficients de partage des éléments traces à haute pression et haute température est aujourd'hui requise afin de tester les différents modèles géochimiques d'évolution du manteau terrestre. Etant données les difficultés inhérentes à l'évaluation de ces coefficients de partage lors d'expériences d'équilibre dans différentes conditions (pression, température, composition chimique, ... ), la modélisation de la distribution de ces éléments traces est nécessaire. Cependant, celle-ci passe par la compréhension des phénomènes microscopiques qui contrôlent l'incorporation de l'élément. Ce travail a porté sur la détermination des différents sites d'accueil du chrome trivalent dans des minéraux du manteau à partir de l'étude de sa luminescence. Cette spectroscopie de luminescence, mise en oeuvre à haute pression en cellule à enclumes de diamant, permet de suivre l'évolution des niveaux d'énergie du cr3+ en fonction de la pression. Nous avons ainsi acquis des données de luminescence sur plusieurs phases cristallines de basse pression (spinelles, pyroxènes, forstérite), de haute pression (grenats, ilménite, pérovskites), et sur des verres silicatés de composition chimique simple. Les résultats obtenus sur les minéraux montrent que le Cr3+ s'incorporent majoritairement dans les sites octaédriques, nécessitant, dans certains cas, une compensation locale des charges. Les mécanismes de substitution, mais aussi l'énergie de stabilisation de l'élément trace dans la structure, dépendent alors fortement de la nature des cations disponibles pour assurer l'équilibre électrostatique. Dans les verres, nous mettons en évidence des variations importantes de la distribution de sites d'accueil en fonction de la composition chimique. La modélisation des paramètres thermodynamiques qui participent au partage du chrome à partir de nos données de haute pression est alors discutée
Download or read book Environmental Barrier Coatings written by Kang N. Lee and published by MDPI. This book was released on 2020-12-29 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: The global increase in air travel will require commercial vehicles to be more efficient than ever before. Advanced engine hot section materials are a key technology required to keep fuel consumption and emission to a minimum in next-generation gas turbines. Ceramic matrix composites (CMCs) are the most promising material to revolutionize gas turbine hot section materials technology because of their excellent high‐temperature properties. Rapid surface recession due to volatilization by water vapor is the Achilles heel of CMCs. Environmental barrier coatings (EBCs) is an enabling technology for CMCs, since it protects CMCs from water vapor. The first CMC component entered into service in 2016 in a commercial engine, and more CMC components are scheduled to follow within the next few years. One of the most difficult challenges to CMC components is EBC durability, because failure of EBC leads to a rapid reduction in CMC component life. Key contributors to EBC failure include recession, oxidation, degradation by calcium‐aluminum‐magnesium silicates (CMAS) deposits, thermal and thermo‐mechanical strains, particle erosion, and foreign object damage (FOD). Novel EBC chemistries, creative EBC designs, and robust processes are required to meet EBC durability challenges. Engine-relevant testing, characterization, and lifing methods need to be developed to improve EBC reliability. The aim of this Special Issue is to present recent advances in EBC technology to address these issues. In particular, topics of interest include but are not limited to the following: • Novel EBC chemistries and designs; • Processing including plasma spray, suspension plasma spray, solution precursor plasma spray, slurry process, PS-PVD, EB-PVD, and CVD; • Testing, characterization, and modeling; • Lifing.
Download or read book Silicate Melts written by Sharon Webb and published by Springer. This book was released on 1997-07-17 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the experimental determination of the physical properties of silicate melts and magmas close to glass transition. Abundant new data are presented. The same type of measurement is performed on a range of melts to test the effect of composition on physical properties; and a range of different techniques are used to determine the same physical properties to illustrate the relationships between the relaxation of the melt structure and the relaxation of its physical properties. This book is of interest to experimental researchers in the discussion of data obtained from both a materials science and a geoscientific point of view.
Download or read book Silicate Glasses and Melts written by Bjorn Mysen and published by Elsevier. This book was released on 2005-06-16 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the structure-property-composition relationships for silicate glasses and melts of industrial and geological interest. From Antiquity to the 20th century, an introductory chapter presents this subject in a historical perspective. Basic concepts are then discussed in three chapters where attention is paid to the glass transition and its various consequences on melt and glass properties, to the structural and physical differences between amorphous and crystalline silicates, and to the mutual relationships between local order, energetics and physical properties. With pure SiO2 as a starting point, compositions of increasing chemical complexity are successively dealt with in a dozen chapters. The effects of network-modifying cations on structure and properties are first exemplified by alkali and alkaline earth elements. The specific influence of aluminum, iron, titanium, and phosphorus are then reviewed. With water, volatiles in the system COHS, noble gases, and halogens, the effects of volatile components are also described. The last chapter explains how the results obtained on simpler melts can be applied to chemically complex systems. In each chapter, physical and chemical properties are described first and followed by a review of glass and melt structure. When possible, pressure effects are also considered.*From SiO2 to complex silicate compositions, the physical and chemical properties of melts and glasses of geological and industrial interest*Structural characterization of melts and glasses, from ambient to high pressure and temperature*From basic concepts to an advanced level, a consistent description of the structure-property-composition relationships in glasses and melts
Download or read book Silicate Glasses and Melts written by Bjorn Mysen and published by Elsevier. This book was released on 2018-11-27 with total page 722 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book Maritime Sediments and Atlantic Geology written by and published by . This book was released on 1988 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings written by and published by . This book was released on 1962 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Effects of Nuclear Transformations written by and published by . This book was released on 1961 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
