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Catalyst deactivation, the loss over time of catalytic activity and/or selectivity, is a problem of great and continuing concern in the practice of industrial catalytic processes. Costs to industry for catalyst replacement and process shutdown total tens of billions of dollars per year. While catalyst deactivation is inevitable for most processes, some of its immediate, drastic consequences may be avoided, postponed, or even reversed. Accordingly, there is considerable motivation to better understand catalyst decay and regeneration. Indeed, the science of catalyst deactivation and regeneration has been developing rapidly as evidenced by the considerable literature addressing this topic, including 21,000 journal articles, presentations, reports, reviews, and books; and more than 29,000 patents for the period of 1980 to 2012. This developing science provides the foundation for continuing, substantial improvements in the efficiency and economics of catalytic processes through development of catalyst deactivation models, more stable catalysts, and regeneration processes. This special issue focuses on recent advances in catalyst deactivation and regeneration, including advances in (1) scientific understanding of mechanisms; (2) development of improved methods and tools for investigation; and (3) more robust models of deactivation and regeneration.
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Natural gas is a vital component of the world's supply of energy and an important source of many bulk chemicals and speciality chemicals. It is one of the cleanest, safest, and most useful of all energy sources, and helps to meet the world's rising demand for cleaner energy into the future. However, exploring, producing and bringing gas to the user or converting gas into desired chemicals is a systematical engineering project, and every step requires thorough understanding of gas and the surrounding environment. Any advances in the process link could make a step change in gas industry. There have been increasing efforts in gas industry in recent years. With state-of-the-art contributions by leading experts in the field, this book addressed the technology advances in natural gas industry.
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The forming of metals through plastic deformation comprises a family of methods that produce components through the re-shaping of input stock, oftentimes with little waste. Therefore, forming is one of the most efficient and economical manufacturing process families available. A myriad of forming processes exist in this family. In conjunction with their countless existing successful applications and their relatively low energy requirements, these processes are an indispensable part of our future. However, despite the vast accumulated know-how, research challenges remain, be they related to the forming of new materials (e.g., for light-weight transportation applications), pushing the boundaries of what is doable, reducing the intermediate steps and/or scrap, or further enhancing the environmental friendliness. The purpose of this book is to collect expert views and contributions on the current state-of-the-art of plastic forming, thus highlighting contemporary challenges and offering ideas and solutions.
Plastic forming --- shaping --- springback --- formability --- numerical simualtions
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Die Verwendung des Konzeptes der Vormischverbrennung in technischen Verbrennungsanlagen fördert die Ausbildung von selbsterregten Instabilitäten.Der Schwerpunkt der Arbeit liegt in der Berechnung des dynamischen Verhaltens bzw. des Frequenzgangs von pulsierten turbulenten vorgemischten Axialstrahlflammen. Dieses steht unter dem Einfluss der Bildung von kohärenten Ringwirbelstrukturen an der Brennermündung. Es werden sowohl instationäre Flammen als auch Ringwirbelströmungen numerisch untersucht.
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Ziel der Arbeit ist es, Vorgänge bei der Adsorption von gelösten Stoffen an hochstrukturierten Phospholipid-Membranen besser zu verstehen. Es wurden aromatische Stoffe als gelöste Stoffe ausgewählt, da diese in vielen Bereichen der Biologie, Pharmazie, Umweltwissenschaften und der Verfahrenstechnik eine bedeutende Rolle spielen.
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The interest in biocompatible and biodegradable metals, such as magnesium, is mainly related to their potential use as structural material for orthopedic and cardiovascular applications where a temporary medical device is required. However, in the case of magnesium, in vivo experiments have clearly shown that the corrosion degradation rate of magnesium and its alloys is too high and, hence, results in producing gas cavities that can promote the danger of gas embolism, tissue separation, and premature loss of mechanical integrity. The aim of this Special Issue on Biodegradable Metals is to explore and introduce innovative strategies to overcome the current limitations of magnesium.
Magnesium --- Iron --- Zinc --- Biomaterials --- Implants --- Biocompatibility --- Biodegradable --- Bioabsorble --- Biocorrosion
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Ziele der vorliegenden Arbeit waren die Entwicklung neuer und die Optimierung bereits angewendeter Methoden für eine dauerhafte ex-situ Kultivierung von Schwämmen als Lieferanten von pharmakologisch interessanten Naturstoffen. Verschiedene Kultivierungsparameter wurden hinsichtlich ihrer Auswirkungen auf die Vitalität und das Wachstum der Schwämme analysiert und vier Kultivierungsansätze getestet: Schwammfragmente, multizelluläre Reaggregate, Gemmulae & die Immobilisierung von Schwammzellen.
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Modern knowledge discovery methods enable users to discover complex patterns of various types in large information repositories. However, the underlying assumption has always been that the data to which the methods are applied to originates from one domain. The focus of this book, and the BISON project from which the contributions are originating, is a network based integration of various types of data repositories and the development of new ways to analyse and explore the resulting gigantic information networks. Instead of finding well defined global or local patterns they wanted to find domain bridging associations which are, by definition, not well defined since they will be especially interesting if they are sparse and have not been encountered before. The 32 contributions presented in this state-of-the-art volume together with a detailed introduction to the book are organized in topical sections on bisociation; representation and network creation; network analysis; exploration; and applications and evaluation.
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Catalyst lifetime represents one of the most crucial economic aspects in industrial catalytic processes, due to costly shutdowns, catalyst replacements, and proper disposal of spent materials. Not surprisingly, there is considerable motivation to understand and treat catalyst deactivation, poisoning, and regeneration, which causes this research topic to continue to grow. The complexity of catalyst poisoning obviously increases along with the increasing use of biomass/waste-derived/residual feedstocks and with requirements for cleaner and novel sustainable processes. This book collects 15 research papers providing insights into several scientific and technical aspects of catalyst poisoning and deactivation, proposing more tolerant catalyst formulations, and exploring possible regeneration strategies.
hydrogenation --- copper --- catalyst --- water --- deactivation --- octanal --- octanol --- V2O5–WO3/TiO2 catalysts --- poisoning --- sulfur-containing sodium salts --- SO3 --- NO removal --- Cu/SSZ-13 --- NH3-SCR --- sodium ions --- deactivation mechanism --- sulfur poisoning --- coke deposition --- in situ regeneration --- Co-Zn/H-Beta --- NOx reduction by C3H8 --- catalyst deactivation --- diesel --- natural gas --- SEM --- TEM --- poisoning --- oxygen storage capacity --- thermal stability --- cyclic operation --- deactivation --- oxysulfate --- oxysulfide --- Selective Catalytic Reduction (SCR) --- SO2 poisoning --- Low-temperature catalyst --- nitrogen oxides --- nitrous oxide --- dry reforming of methane --- nickel catalysts --- barium carbonate --- deactivation by coking --- catalytic methane combustion --- exhaust gas --- catalyst durability --- Liquefied natural gas --- biogas --- vehicle emission control --- sulfur deactivation --- catalyst deactivation --- aluminum sulfate --- palladium sulfate --- regeneration --- phthalic anhydride --- vanadia-titania catalyst --- unusual deactivation --- physico-chemical characterization --- over-reduction --- vanadia species --- coke deposition --- DeNOx --- MW incinerator --- deactivation --- ammonium sulfates --- regeneration --- washing --- CO2 reforming --- Ni-catalyst --- syngas --- tetragonal zirconia --- phase stabilization --- CPO reactor --- effect of flow rate --- deactivation --- iso-octane --- Rh catalysts --- Rh --- homogeneous catalysis --- catalyst deactivation --- n/a
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The great challenge for next years concerning the emission of diesel engines is to develop diesel particle filters (DPF) with catalytic regeneration systems. This work is focused on the global understanding of the diesel soot oxidation on sintered metal filters (SMF). Platinum is studied as reference catalyst. The first objective is to determine which of platinum quantity, platinum particle size, or platinum location exhibits the preponderant influence on the catalytic.
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