L'oxydation thermique est souvent étudiée par les méthodes classiques : mesure thermogravimétrie et observations MEB. L'utilisation de l'EA n'a pas encore été largement développée dans le domaine de l'oxydation thermique. Le présent travail vise à utiliser l'EA pour suivre in-situ l'oxydation et détecter les phénomènes physiques se produisant à haute température. Il porte sur deux groupes de matériaux : sensibles à l'oxydation catastrophique (Ti, Zy-4) et passifs (Cr, Ni). Ce travail présente tout d'abord l'oxydation du Ti pur à 900°C sous 150 mbar d'O2, en tant que matériau modèle. Il aborde également l'influence de la température, de l'atmosphère et de l'état de surface sur le comportement d'EA. L'oxydation du Zy-4, du Cr pur et du Ni pur sous oxygène et/ou sous vapeur d'eau est ensuite étudiée. Les ondes élastiques issues de l'oxydation sont converties en signaux d'EA via un capteur, lequel est collé au côté froid d'un guide d'onde en alumine. Une corrélation entre les mesures d'EA et les résultats classiques a été mise en évidence. La technique d'EA est capable de détecter l'oxydation catastrophique et d'identifier le mode de rupture de l'oxyde. Au-delà des paramètres discriminants d'EA, nous observons deux populations distinctes : la population dite normale est attribuée au bruit de fond et aux relaxations des contraintes dans l'oxyde associées à des phénomènes de fluage micro-mécanique, probablement situé aux joints de grains. La vitesse d'EA peut alors dépendre du niveau de ces contraintes et/ou de leurs relaxations. La population post-transitoire est associée à l'endommagement de l'oxyde conduisant à l'oxydation catastrophique. Selon le niveau d'énergie de transition, le mode de rupture de l'oxyde pourra être identifié. En revanche, l'EA n'a pas donné de résultats probants sur les matériaux passifs. Des signaux enregistrés ont pour principale origine le bruit de fond.

This updated version of Practical Sonochemistry for advanced students and teachers in chemistry and chemical engineering conveys the increasing growth in applications and equipment to power ultrasound. Equipment now on the market offers a wider range of frequencies with more reproducible experimentation and a variety of scale-up systems. The book provides detailed descriptions of newer ultrasonic equipment and its applications, and practical laboratory uses of ultrasound technology for industrial scale performance.Modern exercises familiarise readers with recent sonochemical operations. The book also includes methods for estimating ultrasonic energy entering the system (dosimetry), which will standardise sonochemical methodology and enable practitioners to reproduce results from other laboratories. - Conveys the increasing growth in applications and equipment to power ultrasound - Provides detailed descriptions of new ultrasonic equipment and its applications and practical laboratory uses of ultrasound technology for industrial scale performance - Includes methods for estimating ultrasonic energy entering the system (dosimetry), which will standardise sonochemical methodology and enable practitioners to reproduce results from other laboratories

During the last decades the knowledge of the magnetic properties of the d transition elements and of their metallic alloys and compounds has increased widely. The improvement of preparation techniques for well-defined substances, the development of sophisticated measuring methods and above all the drive to obtain more insight in the origin of magnetic interactions in solids have resulted in the publication of many specific magnetic properties for an abundance of all kinds of metallic materials. The data assembled in this booklet are selected from the comprehensive compilation of magnetic and related properties of metals in the Landolt-Bornstein New Series Group III sub volumes 19a, band c. It has been attempted to include preferentially those properties which are of a basic character and which therefore are most often needed by scientists active in the field of solid state magnetism. In the field of magnetism, there is a gradual transition from the use of cgs/emu units to SI units. It was, however, not intended to represent all data in the units of one system, regardless of how nice this would have been from a systematic point of view. Instead, mostly preference was given to the system of units that was originally used by the authors whose work is quoted. Thus cgs/ emu units occur most frequently. Of colirse the user of the tables and figures is helped in several ways to convert the data to the units which he is most familiar with, see, e. g.

This dual-language dictionary lists over 20,000 specialist terms in both French and English, covering architecture, building, engineering and property terms. It meets the needs of all building professionals working on projects overseas. It has been comprehensively researched and compiled to provide an invaluable reference source in an increasingly European marketplace.

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.

Power ultrasound has been used for many years in two specific industrial areas: cleaning and plastic welding. Over the last ten years an increasing interest has been shown in its potential for use over a much wider range of chemistry and processing which has been grouped together under the general title of sonochemistry. Most of these uses depend on the generation of acoustic cavitation in liquid media but this text, while underlining the importance of the physics and mathematics of cavitation, mainly concentrates on applications of the technology. After an introduction to the topic and some historical background to the uses of power ultrasound the general principles of acoustic cavitation are explored including some background physics, bubble dynamics and factors which influence cavitation. The remainder of the book incorporates a series of applications of sonochemistry which illustrate the types of physical and chemical effects of ultrasonically induced cavitation which will interest chemists and engineers alike. Amongst the major topics included are chemical synthesis, environmental protection and remediation of water, sewage and soils, polymer synthesis and processing, electrochemistry including both analytical and synthetic aspects and plating. The final chapter reviews the range of ultrasonic equipment available in the laboratory and the progress made towards the scale-up of sonochemistry. The level is introductory to semi-advanced and no topic has been taken to a particularly specialist level since it is intended that this should be of general interest to readers with a scientific background.