Download or read book Spectroscopie infrarouge haute r solution en temps pour l tude de la catalyse h t rog ne written by Etienne Séguin and published by . This book was released on 2008 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: La spectrométrie infrarouge à transformée de Fourier permet maintenant d'atteindre des résolutions temporelles de l'ordre de la dizaine de nanoseconde. Nous avons utilisé cette résolution temporelle pour bâtir de nouvelles méthodes d'étude de la catalyse hétérogène. Selon les échelles de temps considérées, de la micro- à la nanoseconde, nous avons étudiés trois domaines principaux, et mis au point trois méthodes expérimentales. Le système de « saut de pression des espèces adsorbées » (2D-IR PJAS) qui permet d’étudier la diffusion de gaz dans des solides poreux a été optimisé pour atteindre la μs, et testé sur une réaction de dimérisation en phase gaz d’un acide carboxylique en estimant des constantes de vitesse de la réaction. Il a ensuite permis de valider un modèle proposé dans la littérature avec l’étude de l’adsorption de benzène sur les hydroxyles d’une zéolithe HY. Le second volet de cette étude a porté sur la conception et la réalisation d’une cellule réacteur IR/micro-ondes 5,8 GHz qui permet l’étude d’une élévation rapide de la température associée à une observation infrarouge du catalyseur sous flux de réactifs. Ce dispositif novateur a permis la détection d’espèces intermédiaires dans une réaction de réduction catalytique sélective du dioxyde d’azote par du méthane. Enfin, nous avons couplé un laser femtoseconde avec un spectromètre IRTF en step scan à 33ns pour étudier les phénomènes de surface ayant des cinétiques très rapides. Nous avons ainsi réalisé la première détection d’un intermédiaire de réaction d’une durée de vie de 2 μs en catalyse hétérogène de déNOx sur argent supporté sur alumine.
Download or read book Spectroscopie infrarouge ultra haute r solution appliqu e l tude de sym tries fondamentales dans les mol cules written by and published by . This book was released on 2001 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: [Résumé français] La première partie de ce mémoire est consacrée à la mise en oeuvre d'une nouvelle expérience de recherche d'un effet de violation de parité par l'interaction faible dans le spectre de molécules énantiomorphes. Cette étude constitue l'aboutissement de travaux réalisés en cellules sur ce sujet. Elle repose sur la comparaison des fréquences de transitions rovibrationnelles des deux énantiomères de la molécule chirale CHFCIBr enregistrées simultanément, avec le même laser à CO2 asservi en fréquence. Pour l'occasion, l'ensemble du spectromètre a été optimisé et adapté aux besoins de l'expérience. Nous avons aussi réalisé l'étude de la structure hyperfine de CHFCIBr afin de sélectionner les transitions les plus favorables pour le test. Ceci nous a permis d'obtenir une sensibilité ínégalée de 2.10-14 en valeur relative soit un gain de plus d'un ordre de grandeur sur la précédente mesure. Un diagnostic précis des limitations ultimes de cette expérience a également pu être établie. La seconde partie présente le premier test du postulat de symétrisation réalisé dans les molécules polyatomiques. Il s'agit cette fois de vérifier que les états quantiques qui ne sont pas totalement symétriques dans l'échange des oxygènes de la molécule OsO4 et antisymétriques dans l'échange des fluors de la molécule SF6 ne sont pas peuplés. Le principe du test consiste alors à comparer l'amplitude des transitions infrarouges entre niveaux permis à des transitions entre niveaux interdits par le postulat. Contrairement aux expériences recensées jusqu'à présent, les molécules que nous avons choisies permettent d'étudier des symétries interdites de dimension supérieure à 1. Pour OsO4, la borne supèrieure de l'effet a été fixé à 5.10-4 en valeur relative, limitée par la présence de bandes chaudes en quasi-coïncidence avec les transitions recherchées. Pour SF6 la borne a été fixée à 7,8.10-6 limitée cette fois par le rapport signal-sur-bruit.
Download or read book Adhesion between polymers and concrete Adh sion entre polym res et b ton written by H. R. Sasse and published by Springer. This book was released on 2013-11-27 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Preface Adhesion is a phenomenon architects and civil engineers are not very familiar with. In other disciplines knowledge about surface properties and the background of bonding energies is also far from satisfactory; nevertheless there are many important· applications in concrete engineering, where adhesion is necessary for success and durability. These include: - coating and painting - repair of concrete surfaces - bonding of fresh to old concrete - crack injection - glueing of precast elements - glueing of steel to concrete, etc. In 1981 RILEM established the technical committee 52-RAC 'Resin Adherence to Concrete'. The main aims of the committee's work were - to collect research results and practical experiences - to initiate and coordinate research programs - to develop, on a scientific base, test methods for field and for laboratory purposes. One of the results of the committee's work is a state-of-the-art report, which will be presented orally as a General Report at the International Symposium ISAP '86, and will be printed either in the RILEM journal Materials and Structures or separately. Several test recommendations have been elaborated and will be prepared as drafts for the participants ofISAP '86. These are: - direct tensile test - pull-off test - direct shear test - slant shear test - four-point bending test - dynamic loading test - thermal compatibility test (two versions) - injectibility test.
Download or read book Stored grain Insects written by United States. Agricultural Research Service and published by . This book was released on 1978 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Graphene written by Wonbong Choi and published by CRC Press. This book was released on 2016-04-19 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the late 20th century, graphene-a one-atom-thick planar sheet of sp2-bonded carbon atoms densely packed in a honeycomb crystal lattice-has garnered appreciable attention as a potential next-generation electronic material due to its exceptional properties. These properties include high current density, ballistic transport, chemical inertness,
Download or read book Agrochimica written by International Atomic Energy Agency and published by . This book was released on 1977 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: Organic matter and soil productivity; Turnover of plant residues; Mineralization of organic compounds; Dynamics of organic forms of nitrogen; Nitrogen economy; Biodegradation of organic matter; Biochemical transformation of organic matter; Bitumens in soil organic matter; Characterization of humic acids; Carbon dating; Modern techniques and their implact on soil organic matter research; Sludge; Soil organic matter components and plant metabolism; Interaction between agrochemicals and organic matter; Peat.
Download or read book A German English Dictionary for Chemists written by Austin McDowell Patterson and published by . This book was released on 1935 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Narratives of fear and safety written by Kaisa Kaukiainen and published by BoD - Books on Demand. This book was released on 2020-09-01 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: The essays in this edited volume, written in English and French, tackle the intriguing problems of fear and safety by analysing their various meanings and manifestations in literature and other narrative media. The articles bring forth new, cross-cultural interpretations on fear and safety through examining what kinds of genre-specific means of world-making narratives use to express these two affectivities. The articles also show how important it is to study these themes in order to understand challenges in times of global threats, such as the climate crisis. The main themes of the book are approached from various theoretical perspectives as related to their literary and cultural representations. Recent trends in research, such as affect and risk theory, serve as the basis for the discussion. The articles in the volume also draw from disciplines such as gender studies and trauma studies to examine the threats posed by collective fears and aggression on individuals' lives and propose ways of coping with fear. These themes are addressed also in articles analysing new adaptations of old myths that retell stories of the past. Many of the articles in the volume discuss apocalyptic and dystopian narratives that currently permeate the entire cultural landscape. Dystopian narratives do not only deal with future threats, such as totalitarianism, technocracy, or environmental disasters, but also suggest alternative ways of being and new hopes in the form of political resistance.
Download or read book Alpha particle Calibrations written by J. M. R. Hutchinson and published by . This book was released on 1987 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Before We Visit the Goddess written by Chitra Banerjee Divakaruni and published by Simon and Schuster. This book was released on 2017-04-25 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A new novel from the author of Oleander Girl, a novel in stories, built around crucial moments in the lives of 3 generations of women in an Indian/Indian-American Family"--
Download or read book Conservation of Building and Decorative Stone written by F G Dimes and published by Routledge. This book was released on 2007-11-02 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the problems which beset the practical conservation of stone buildings is the fragmentation of the disciplines involved. This book, with both volumes now available as one invaluable paperback, brings these disciplines together by the involvement of contributors with different experiences and approaches to the same material. Part one is an introduction to the complexities and background history of stone conservation followed by the most comprehensive description yet produced of the building and decorative stones used in the British Isles. In part two, practitioners involved in stone conservation describe ways in which major structural masonry problems, secondary building problems and different stone surface conditions may be treated. A variety of building types and environments has been used to ensure that the broad scope of common problems is covered. This second part of the book will be of practical value to art historians, archaeologists, architects, surveyors and engineers, masonry contractors and sculpture conservators in solving problems and in learning to use each other's skills and experience.
Download or read book Flexoelectricity in Liquid Crystals written by Agnes Buka and published by World Scientific. This book was released on 2013 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.
Download or read book Platform Chemical Biorefinery written by Satinder Kaur Brar and published by Elsevier. This book was released on 2016-06-02 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: Platform Chemical Biorefinery: Future Green Chemistry provides information on three different aspects of platform chemical biorefinery. The book first presents a basic introduction to the industry beneficial for university students, then provides engineering details of existing or potential platform chemical biorefinery processes helpful to technical staff of biorefineries. Finally, the book presents a critical review of the entire platform chemical biorefinery process, including extensive global biorefinery practices and their potential environmental and market-related consequences. Platform chemicals are building blocks of different valuable chemicals. The book evaluates the possibility of renewable feedstock-based platform chemical production and the fundamental challenges associated with this objective. Thus, the book is a useful reference for both academic readers and industry technical workers. The book guides the research community working in the field of platform chemical biorefinery to develop new pathways and technologies in combination with their market value and desirability. Offers comprehensive coverage of platform chemicals biorefineries, recent advances and technology developments, potential issues for preventing commercialization, and solutions Discusses existing technologies for platform chemicals production, highlighting benefits as well their possible adverse effects on the environment and food security Includes a global market analysis of platform chemicals and outlines industry opportunities Serves as a useful reference for both academic readers and industry technical workers
Download or read book Modern Surface Organometallic Chemistry written by Jean-Marie Basset and published by John Wiley & Sons. This book was released on 2009-07-10 with total page 725 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covering everything from the basics to recent applications, this monograph represents an advanced overview of the field. Edited by internationally acclaimed experts respected throughout the community, the book is clearly divided into sections on fundamental and applied surface organometallic chemistry. Backed by numerous examples from the recent literature, this is a key reference for all chemists.
Download or read book In Vessel Melt Retention and Ex Vessel Corium Cooling IAEA Tecdoc No 1906 written by International Atomic Energy Agency and published by International Atomic Energy Agency. This book was released on 2020-08-06 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication results from a technical meeting on phenomenology and technologies relevant to in-vessel melt retention (IVMR) and ex-vessel corium cooling (EVCC). The purpose of the publication is to capture the state of knowledge, at the time of that meeting, related to phenomenology and technologies as well as the challenges and pending issues relevant to IVMR and EVCC for water cooled reactors by summarizing the information provided by the meeting participants in a form useful to practitioners in Member States.
Download or read book Nitroxides written by Olivier Ouari and published by Royal Society of Chemistry. This book was released on 2021-05-13 with total page 611 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitroxides are versatile small organic molecules possessing a stabilised free radical. With their unpaired electron spin they display a unique reactivity towards various environmental factors, enabling a diverse range of applications. They have uses as synthetic tools, such as catalysts or building blocks; imaging agents and probes in biomedicine and materials science; for medicinal antioxidant applications; and in energy storage. Polynitroxides (polymers bearing pendant nitroxide sidechains) have been used in organic radical batteries, oxidation catalysts and in exchange reactions for constructing complex architectures. Chapters in this book cover the synthesis of nitroxides, EPR studies and magnetic resonance applications, physiochemical studies, and applications including in batteries, imaging and organic synthesis. With contributions from leaders in the field, Nitroxides will be of interest to graduate students and researchers across chemistry, physics, biology and materials science.
Download or read book Phytochemicals in Nutrition and Health written by Mark S. Meskin and published by CRC Press. This book was released on 2002-03-19 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: Are soy isoflavones neuroprotective? Just how different is one species of Echinacea from another? Which phytochemicals will be effective as therapeutic agents in vivo? Supported by solid scientific research, Phytochemicals in Nutrition and Health helps provide answers to these and other probing questions concerning the mechanisms of action associat
