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This report covers a study concerning the methods that are available for determining the cleanness level for steels. No outstanding method is available for rating clean steels, when clean steel is defined as free of fatigue initiating inclusions. Fatigue strength is to a large extent dependant of the biggest inclusion size in the stressed volume. Examples of methods that can be used for finding and testing material for the presence of big inclusions is reported.

Mapping of the north-eastern portion of the Bird1s River Complex revealed that two large xenoliths composed of pyroclastic rocks and sandstone of the Cave Sandstone Stage have reacted with the dolerite. All the reaction phenomena normally associated with Karroo Dolerite are encountered. These are: (a) Metasomatism during the stage of iron enrichment of the dolerite with the production of a pyroxene-plagioclase metasomatic granophyre (b) Metasomatism during the stage of alkali enrichment of the dolerite with the production of a potassium feldspar adinole C c) Assimilation 'vi th the production of contaminated doleri tes Cd) Fusion 'vi th the production of glassy rocks including buchi tes (e) The production of rheomorphic veins

Le présent travail comporte une analyse du comportement sismique des sols renforcés par des inclusions rigides. L’étude est effectuée à l’aide d’une modélisation numérique tridimensionnelle par différences finies de l’interaction sol-matelas-inclusions-structure. Le comportement du sol est supposé de type élastoplastique avec un amortissement de type Rayleigh. Le travail est présenté en trois chapitres.Le premier chapitre comporte une synthèse des travaux réalisés sur les inclusions rigides et sur l’analyse de leur comportement en zone sismique. Il présente d’abord la technologie de renforcement par inclusions rigides ainsi que son utilisation et les méthodes de calcul sous chargement statique. Ensuite, il donne une synthèse des approches utilisées pour l’analyse de l’interaction sol-structure sous chargement sismique, et plus particulièrement pour les groupes de pieux et les inclusions rigides.Le second chapitre est consacré à l’analyse de l’interaction cinématique du système sol-matelas-inclusions-structure. L’analyse est effectuée à l’aide d’une approche globale qui consiste à calculer la réponse de l’ensemble des éléments du système à un chargement sismique. Elle est réalisée à l’aide d’une modélisation tridimensionnelle et non linéaire du système de renforcement. Le chapitre est composé de trois parties. La première expose le modèle numérique utilisé, la seconde présente une analyse d’un sol renforcé par un groupe de 2x2 inclusions rigides, la dernière est consacrée à une étude de l’influence de principaux paramètres sur la réponse sismique du groupe d’inclusions rigides.Le dernier chapitre est consacré à l’étude de l’influence de la présence de la structure sur l’interaction sol-matelas-inclusions-structure. L'accent est mis sur l’influence des paramètres majeurs tels que les caractéristiques géométriques et mécaniques du matelas, la rigidité des inclusions, les conditions de liaison inclusions-matelas et l’amplitude du chargement. Ce chapitre donne aussi une comparaison entre le comportement sismique des inclusions rigides avec celui d’un groupe de colonnes de module mixte (CMM) et d’un groupe de pieux. / This work includes an analysis of seismic behaviour of soft soil improved by vertical rigid inclusions. The study is conducted by using a three-dimensional finite-difference numerical modelling of soil-gravel layer-inclusions-structure interaction. Soil media is assumed to be elastoplastic with Rayleigh damping. The work is presented in three chapters. The first chapter deals with a review of the literature on research previously conducted on rigid inclusions and their behaviour in seismic areas. Firstly, the technology of soft soil improvement by vertical rigid inclusions, its domains of applications and methods of calculation under static loading are presented. Then, a synthesis of approaches used to evaluate soil-structure interaction under seismic loading is reviewed; we focus more precisely on methods concerned the grouped piles and rigid inclusions.The second chapter is devoted to the analysis of kinematic interaction of soil_gravel layer-inclusions-structure system. The analysis is performed using a global approach which consists of calculating the response of all elements composing the latter system under seismic loading. The analysis is carried out by a nonlinear three-dimensional numerical modelling of the soil reinforcement system. The chapter is divided into three parts. The first one outlines the used numerical model; the second presents an analysis of a soil reinforces by a group of four rigid inclusions. In the third part, we present a parametric study which covers the influence of main parameters on the seismic response of the rigid inclusions group.The last chapter is devoted to the study of the influence of the presence of structure on the soil-gravel layer-inclusion-structure interaction. The influence of major parameters is highlightened by a parametric study concerns the effect of geometric and mechanical characteristics of the gravel layer, inclusion rigidity, the inclusions-gravel layer connection conditions and the amplitude of the seismic loading. The chapter gives a comparison between the seismic behaviour of rigid inclusion (IR) to both column with mixed module (CMM) and a group of classical piles.

Please read the abstract in the 00front part of this document / Dissertation (MSc (Metallurgy))--University of Pretoria, 2007. / Materials Science and Metallurgical Engineering / unrestricted

Kimberlite, an ultrabasic diamond-bearing hypabyssal rock-type which has its origin in the Earth's upper mantle, characteristically contains rare, well-rounded xenoliths of peridotite and eclogite. These xenoliths, which undoubtedly originate from some considerable depth below the Earth's surface, possibly represent samples of upper mantle material. They have received much attention from earth scientists and numerous theories as to their origin have been proposed. Forty-two selected peridotite xenoliths from the Bultfontein, Wesselton, Dutoitspan and Roberts Victor kimberlite pipes of the Kimberley area, South Africa, and 24 eclogite xenoliths from the Roberts Victor pipe have been examined in detail using a variety of petrological and mineralogical techniques. The petrologic research comprises conventional petrographic studies, the determination of accurate modal compositions and the presentation of 22 new whole-rock chemical analyses, nine of which are of garnet peridotite, four of spinel peridotite and nine of eclogite, one being a diamondiferous specimen. Detailed mineralogical studies of the constituent minerals of the xenoliths comprises descriptive mineralogy, in most cases an estimation of the compositions of these minerals from the measurement of physical properties, X-ray powder diffraction data and the presentation of 21 new chemical analyses of pure mineral separates. This includes five analyses of clivine, five of orthopyroxene, eight of garnet, one of chrome diopside and two of omphacite. The results of the investigation have shown that the peridotites consist essentially of forsterite and enstatite with minor or trace amounts of one or more of pyrope-rich garnet, chrome diopside, chrome spinel, phlogopite and rarely graphite, and often exhibit features consistent with plastic movement and tectonic deformation. The peridotites are believed to be derived from an ultrabasic upper mantle, which is both chemioally and physically zoned. The eclogite xenoliths, which are composed mainly of pyrope-almandine garnet and omphacitic clinopyroxene and occasionally contain kyanite, corundum and diamond, are not samples of a primary eclogitic upper mantle nor the products of an eclogite fractionation related to kimberlite genesis. Chemically they are not typical of extrusive basalts and probably either represent pockets of partially fractionated basic magma trapped at mantle-level in an eclogite-stable environment or samples of high-grade crustal metamorphic eclogite accidentally incorporated into the Roberts Victor kimberlite.

L’étude des inclusions fluides individuelles, témoin des paléofluides, pose des défis analytiques majeurs aux géochimistes. La mise au point de la technique LA-ICPMS ouvre des perspectives prometteuses. Un triple objectif autour de l’utilisation de LA-ICPMS pour l’analyse d’inclusions fluides définit cette thèse. Tout d’abord, un travail basé sur la chimiométrie permettant de définir un protocole expérimental adaptable a été couplé à la réalisation de courbes de calibrage sur 3 à 4 ordres de grandeur pour tous les éléments analysés. Le développement d’une démarche rigoureuse basée sur un traitement du signal et un modèle thermodynamique a permis la quantification du contenu ionique (éléments majeurs et traces) des inclusions fluides. Le développement d’un logiciel de traitement des données est venu finaliser cet objectif. Enfin, l’étude de différentes cibles naturelles a été divisée en trois parties. Les halogénures Cl, Br et I sont des informations utiles dans l’étude de l’origine des fluides. Une approche originale basée sur la courbe de calibration de Br a permis d’analyser dans trois types de fluides différents les rapports Cl/Br. La seconde étude a porté sur l’analyse de l’argent et d’autres éléments des paragénèses contenus dans les fluides de différents gisements argentifères. La dernière partie est basée sur la faisabilité d’obtenir les concentrations des terres rares dans des inclusions fluides favorables / The study of paleofluids by using fluid inclusions analysis is an important challenge in geochemistry. The LA-ICPMS technique allows enlarging the field of possibilities by determining the cationic content in fluid inclusions. Three aims, with LA-ICPMS as the thesis centre, are developed here: (i) the calibration of LA-ICPMS associated with a work on chimiometry give the possibility of this analytical technique and experimental protocol adapted; (ii) The development of a calculation method based on Pitzer’s themodynamic model. The quantification of cationic content (trace and major elements) is improved. In parallel, a software is developed to facilitate the processing of raw signal, (iii) the study of different targets is made. The Cl/Br concentration ratios are used to get information of the fluids origin. Then, a analysis on four different natural targets linked with silver deposits is realized. The last point is the feasabilty of the determination of rare earth element in fluid inclusion of Mac Arthur River (Uranium deposit, Canada)

Title: Dynamics of structural defects in CdTe-based semiconductors Author: RNDr. Marek Bugár Institute: Institute of Physics, Charles University in Prague Supervisor of the doctoral thesis: Doc. Ing. Eduard Belas CSc.; Institute of Physics, Charles University in Prague Abstract: The work was aimed at investigation of the effect of annealing on structural, electrical and optical properties of CdZnTe epitaxial substrates and CdTe-based and CdZnTe-based X-ray and gamma-ray detectors. The first part of the work is focused on investigation of structural properties of one type of second phase defects - inclusions - present in the material, which degrade the material quality. Consequent annealing experiments were aimed at reduction of these defects. In case of CdZnTe substrates, an annealing treatment leading to increase of the infrared transmittance was investigated. On the other hand, annealing experiments on the detectors of high-energetic radiation were focused on preservation of the high-resistive state. Moreover, the work contains detailed measurements of transport properties of CdTe taken directly at high temperatures. Key words: CdTe, annealing, inclusions, detectors, defects

<p>A comprehensive study of inclusion aggregation and removal in different bottom gas-stirred ladles has been conducted. The unsteady, three dimensional, isothermal, multiphase computational fluid dynamics (CFD) model was developed. A ladle with two bottom plugs was used in the study. Effects of plug separation angles (180° and 90°) and argon flow rate combinations (5/5 SCFM, 5/20 SCFM and 20/20 SCFM) were investigated. The whole study can be divided into two parts: first, the flow field, slag eye size and wall shear stress have been studied; second, inclusion aggregation and removal in different ladles have been investigated. In the first part, argon bubble breakup and coalescence has been considered. The slag eye size was validated with plant measurement. When the flow rate increases, the size of slag eye will increase while the wall shear stress increases as well. In the second part, a parametric study of ladle design and argon flow rate on inclusion aggregation and removal has been conducted. Turbulence shear collision shows the most dominant effect on inclusion aggregation. The argon flow rate is positively related to inclusion aggregation and removal. When the argon flow rate is fixed, a larger plug separation angle shows higher inclusion aggregation and removal efficiency. </p><br>

The present work was to study the role of ladle glaze as apotential supplier of inclusions to the steel melt during theladle refining process. In this study, the total number ofinclusions at the beginning and at the end of the ladletreatment process was found to be increasing with ladle age,which is the number of heats, the ladle being used. Asubstantial increase in inclusion population was noticed aftera certain ladle age. Totally four types of inclusions named as; type-1 (MgO),type-2 (spinel), type-3 (an oxide solution) and type-4 (spinelin the center surrounded by the oxide solution of type-3) wereobserved in the beginning of the ladle refining process.Thermodynamic calculation revealed that the type-3 and type-4inclusions were generated by the reactions between EAF slag andladle glaze. Even a part of inclusions of type-2 (spinel phase)could be formed by these reactions. Three types of inclusionswere found before casting, viz. type-5 (oxide solution with lowcontents of MgO and SiO2), type-6 (small MgO islands embeddedin an oxide solution) and type-7 (spinel in the centersurrounded by the oxide solution of type-5). Inclusions of bothtype-5 and type-7 were the products of the reaction betweeninclusions of type-2 and the liquid metal. On the other hand,the occurrence of pieces of MgO having sharp edges in the oxidesolution suggested that the type-6 inclusions were generated bythe ladle glaze. A preliminary examination on the possibility of inclusionseparation by bubble floatation, experiments using cold modelswere also carried out. De-ionised water and silicon oil wereused as the bulk phase. Charcoal particles of different sizeranges were employed as the dispersed phase. The examination ofcharcoal-water-gas system indicated that the positivefloatation coefficient is not a sufficient condition for theinclusion separation. The experimental results were found to bein contradiction with the prediction of a typical model thatconsiders interfacial energies. The omitting of the drag forcewas believed to be the reason causing the failure of the modelprediction in the charcoal-water-gas system. The failure of themodel prediction suggested a need of a new model taking intoaccount interfacial energies, drag force, buoyancy force andgravity force. <b>Key words:</b>oxide inclusions, ladle metallurgy, ladleglaze, inclusion population, ladle age, interfacial tension,inclusion separation / NR 20140805