Hong Yong Sohn

Bio: Hong Yong Sohn is an academic researcher from University of Utah. The author has contributed to research in topics: Hydrogen & Reaction rate. The author has an hindex of 38, co-authored 404 publications receiving 8106 citations. Previous affiliations of Hong Yong Sohn include Center for Advanced Materials & University of New Brunswick.

Gas-solid reactions

Abstract: Preface In recent years considerable advances have been made in our understanding of gas-solid reaction systems. These advances are due in part to the development of more sophisticated mathematical models in which account is taken of such structural effects as pore size, grain size, and pore diffusion. Another important contributory factor has been the use of more sophisticated experimental techniques such as electron microscopy, X-ray diffraction, and porosimetry, which together with pore diffusion measurements provide information on the key structural parameters and make possible the critical assessment of this new generation of models. These new developments were motivated to a great extent by the societal and economic importance of gas-solid reaction systems due to their relevance for a broad range of processing operations, including iron oxide reduction, the combustion of solid fuels, the desulfurization of the fuel gases, and the incineration of solid wastes. The purpose of this monograph is to present in an integrated form a description of gas-solid reaction systems, where full account is taken of these new developments and where structural models of single particle systems, experimental techniques, the interpretation of measurements, the design of gas-solids contacting systems, and practical applications are treated in a unified manner. The actual approach to be developed here is based on methodology similar to that employed in chemical reaction engineering in the interpretation of rate data and the design of process systems in heterogeneous catalysis. More specifically, through the use of this methodology, the individual components of the overall reaction sequence are studied and examined in isolation and the description of the system is then synthesized from these components. This approach provides greatly improved insight and at the same time allows a much broader generalization of the results than is possible through the use of empirical models. While there is a close parallel between heterogeneous catalytic reaction systems and gas-solid reactions, the latter systems are rather more complicated because of the direct participation of the solid in the overall reaction. As the solid is consumed or undergoes chemical change, its structure changes continuously, making the system inherently transient. It follows that the analysis of gas-solid reactions involves an additional dimension, that of time, which is not necessarily needed in the study of heterogeneous gas-solid reactions. The inherently unsteady nature of gas-solid reaction systems introduces a number of complicating factors which render the tackling of these problems a definitely nonroutine task requiring originality. It is noted here that while the discussion in this text is devoted to gas-solid reactions, with little modification the treatment developed here should be applicable to liquid-solid reaction systems. The material presented here could form part of a one-semester graduate level course to be given to students either in metallurgy (materials engineering) or in chemical engineering. It is hoped, moreover, that the book will appeal to the growing number of practicing engineers engaged in process research, development, and design in the many fields where gas-solid reactions are of importance.

Synthesis, sintering, and mechanical properties of nanocrystalline cemented tungsten carbide - A review

Abstract: Nanocrystalline WC–Co materials have been the subject of interests and focus of research programs around the world for the past two decades owing to the expectations that the mechanical behavior of the material may improve significantly when grain sizes reduce to nanometer scale. However, although numerous technologies are available for making nanosized tungsten carbide powders, obtaining true nanocrystalline WC–Co (average WC grain size

Rate Processes of Extractive Metallurgy

Abstract: Computer technology in the past fifteen years has essentially rev olutionized engineering education. Complex systems involving coupled mass transport and flow have yielded to numerical analysis even for relatively complex geometries. The application of such technology together with advances in applied physical chemistry have justified a general updating of the field of heterogeneous kinetics in extractive metallurgy. This book is an attempt to cover significant areas of extrac tive metallurgy from the viewpoint of heterogeneous kinetics. Kinetic studies serve to elucidate fundamental mechanisms of reac tions and to provide data for engineering applications, including improved ability to scale processes up from bench to pilot plant. The general theme of this book is the latter-the scale-up. The practicing engineer is faced with problems of changes of order of magnitude in reactor size. We hope that the fundamentals of heterogeneous kinetics will provide increasing ability for such scale-up efforts. Although ther modynamics is important in defining potential reaction paths and the end products, kinetic limitations involving molecular reactions, mass trans port, or heat flow normally influence ultimate rates of production. For this reason, rate processes in the general field of extractive metallurgy have been emphasized in this book."

Hydrogen storage properties of nanosized MgH2-0.1TiH2 prepared by ultrahigh-energy-high-pressure milling

Abstract: Magnesium hydride (MgH2) is an attractive candidate for solid-state hydrogen storage applications. To improve the kinetics and thermodynamic properties of MgH2 during dehydrogenation−rehydrogenation cycles, a nanostructured MgH2−0.1TiH2 material system prepared by ultrahigh-energy−high-pressure mechanical milling was investigated. High-resolution transmission electron microscope (TEM) and scanning TEM analysis showed that the grain size of the milled MgH2−0.1TiH2 powder is approximately 5−10 nm with uniform distributions of TiH2 among MgH2 particles. Pressure−composition-temperature (PCT) analysis demonstrated that both the nanosize and the addition of TiH2 contributed to the significant improvement of the kinetics of dehydrogenation and hydrogenation compared to commercial MgH2. More importantly, PCT cycle analysis demonstrated that the MgH2−0.1TiH2 material system showed excellent cycle stability. The results also showed that the ΔH value for the dehydrogenation of nanostructured MgH2−0.1TiH2 is signifi...

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

Commentary: The Materials Project: A materials genome approach to accelerating materials innovation

Abstract: Accelerating the discovery of advanced materials is essential for human welfare and sustainable, clean energy. In this paper, we introduce the Materials Project (www.materialsproject.org), a core program of the Materials Genome Initiative that uses high-throughput computing to uncover the properties of all known inorganic materials. This open dataset can be accessed through multiple channels for both interactive exploration and data mining. The Materials Project also seeks to create open-source platforms for developing robust, sophisticated materials analyses. Future efforts will enable users to perform ‘‘rapid-prototyping’’ of new materials in silico, and provide researchers with new avenues for cost-effective, data-driven materials design. © 2013 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.