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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Numerický model pro vznik magmatických textur a jeho využití ve smrčinském granitovém batolitu / Numerical model for the origin of magmatic textures and its application to the Fichtelgebirge/Smrčiny granite batholith

Špillar, Václav January 2011 (has links)
Magmatic processes are major agents responsible for the formation and differentiation of the Earth's crust. In contrast to extensive efforts to improve understanding and utility of igneous geochemistry, physical processes of magma differentiation and solidification remain largely unclear. Large variability of igneous textures provides record of these processes and intensive parameters governing the crystallization. In this thesis, we develop quantitative methods, which allow us to better interpret igneous textures in the framework of physics of solidification. We have developed a new three-dimensional model of crystallization from one- component melt driven by homogeneous and heterogeneous nucleation and crystal growth. The predicted textures are quantitatively characterized by crystal size distributions, spatial distribution functions and parameters representing grain contact relationships. The model employs high resolution in a large volume simulation domain in order to produce statistically stable results. Our simulations, performed for various functional forms of nucleation and growth rates with respect to time, imply that (i) crystals are ordered (anti-clustered) on short length scales. This reflects that other crystals already have a finite size at the time of nucleation of younger crystal,...
42

Impact of mixed solvent on co-crystal solubility, ternary diagrams and crystallisation scale-up. Crystallisations of Isonicotinamide ¿Benzoic Acid Co-crystals from Ethanol ¿Water Co-solvent System.

Redha, Batul H. January 2012 (has links)
The production of stable solid crystalline material is an important issue in the pharmaceutical industry and the challenge to control the desired active pharmaceutical ingredient (API) with the specific chemical and physical properties has led to more development in the drug industry. Increasing the solubility and the dissolution of the drug will increase its bioavailability; therefore the solubility can be improved with the change in the preparation method. The formation of co-crystals has emerged as a new alternate to the salts, hydrates and solvate methods since the molecules that cannot be formed by the usual methods might crystallise in the form of co-crystals. Co-crystals are multicomponent crystals which can be known as supramolecules and are constructed by the non covalent bonds between the desired former and co-former. Therefore the synthon approach was utilised to design co-crystals with the specific properties, this involves the understanding of the intermolecular interactions between these synthons. These interaction forces can be directed to control the crystal packing in the design of the new crystalline solid with the desired chemical and physical properties. The most familiar synthon was the amide group with its complementary carboxylic group, in this work isonicotinamide and benzoic acid were chosen to design co-crystal and much literature exist that introduce the determination of co-crystal growth from these two compounds. The growth of co-crystals was carried out in water, ethanol and ethanol / water mixed solvent (30 - 90 % ethanol) by utilising the Cryo-Compact circulator. Co-crystals (1:1) and (2:1) were grown in ethanol and water respectively and a mixture of both phases were grown in the mixed solvent. All the phases were examined by powder X-ray diffraction (PXRD), Raman, Infrared and 1H-NMR spectroscopy. The solubility of isonicotinamide, benzoic acid, co-crystals (1:1) and (2:1) in water, ethanol and ethanol/water mixed solvent (30 - 90 % ethanol) were determined at 25 °C, 35 °C and 40 °C by utilising the React-Array Microvate. It was important to understand some of the thermodynamic factors which control the formation of these polymorphs such as the change in the enthalpy and the change in the entropy. Also it was important to study the pH behaviour during dissolution of the former, co-former and co-crystals in water, ethanol and ethanol/water mixed solvent (30 - 90 % ethanol) in-order to examine the affect of the solvent composition on the solubility and to identify if some ions were formed during the dissociation and how this could affects the formation of co-crystals. A discussion has been introduced in this research of how similar solubility of the compounds maps the formation of the typical ternary phase diagram of the mixture of 1:1 while compounds with different solubility maps the formation of skewed phase diagram as shown in section 1.6.2.3. In this project an isotherm ternary phase diagram at 20 °C and 40 °C was constructed to map the behaviour of benzoic acid and isonicotinamide and to show all possible phases formed and the regions where all phases are represented in the ternary phase diagram were determined by the slurry method. The ternary phase diagram was used to design a drawn out and cooling crystallisation at 100 cm3 solution of 50 % ethanol / water mixed solvent and a study of the impact of seeds of co-crystals 1:1 on the cooling crystallisation method.
43

Improved Helicopter Rotor Performance Prediction through Loose and Tight CFD/CSD Coupling

Ickes, Jacob January 2014 (has links)
No description available.
44

Expression und Funktion von Caveolin bei glialen Zellen, insbesondere Oligodendrozyten / Aufgabe und Funktion von oligodendroglialem Caveolin und Caveolin-haltigen Mikrodomänen (CMD) bei der NGF-Signaltransduktion / Expression and function of caveolin in glial cells, especially oligodendrozytes / Role and functions of oligodendroglial caveolin and caveolin-containing microdomains (CMD) in NGF-signalling

Schmitz, Matthias 04 May 2006 (has links)
No description available.
45

Corporate social responsibility and gambling industry : an exploratory study

Leung, Cheng Han January 2014 (has links)
Corporate Social Responsibility (CSR) is one important response to the increasing amounts of criticism levelled at corporations. A number of studies have focused on CSR in a range of industries; however, some contentious industries, e.g. the gambling industry, remain unexplored. Mobilizing CSR in a novel setting not only enhances the knowledge of CSR and gambling, but also provides an overview of this industry itself. This thesis attempts to investigate three questions: to what extent does the gambling industry disclose CSR-related data, how is CSR understood in this industry and why does the gambling industry engage in CSR? This thesis provides a general overview of the international gambling industry and an in-depth investigation of Macao's gambling industry. The research design of the thesis employs mixed methods: content analysis and semi-structured interviews. The principal research is based on 49 interviews. This thesis advances three main arguments. First, it will be argued that there are relatively low volumes of Corporate Social Disclosure (CSD) and Responsible Gambling (RG) disclosure in the international gambling industry, which can be viewed as a legitimising strategy. Second, in Macao's gambling industry, it is argued that organisations in this industry tend to place a greater emphasis on positive social impacts, while obscuring such negative impacts as gambling addiction and health-related issues. Third, this thesis holds that organisations in Macao's gambling industry engage symbolically, rather than substantively, with CSR and RG in order to manage stakeholders' perceptions in an attempt to gain different sources of legitimacy and in turn to enhance its economic interests. In conclusion, the gambling industry does not entirely conform to the institutional environment, which poses a challenge to the organisational legitimacy literature. This thesis introduces a necessary caution into the discussions about the extent of CSD, CSR, and RG in this industry more generally.
46

Relationen mellan styrelsens diversitet, innovativa företag och hållbarhetsredovisningens sociala aspekter

Andersson, Sandra, Östergren, Ingela January 2015 (has links)
Studiens syfte är att beskriva och statistiskt analysera relationen mellan styrelsens diversitet och hållbarhetsredovisningen med innovativa företag som medierande variabel. Då en hållbarhetsredovisning utgörs av flera kategorier fokuserar studien på de sociala aspekterna: produktansvar, arbetsförhållanden och arbetsvillkor, organisationens roll i samhället och mänskliga rättigheter. För att uppnå studiens syfte har en kvantitativ studie med deduktiv ansats utförts. Data har samlats in från GRIs (Global reporting initiative) databas där totalt202 multinationella företag som redovisat enligt GRIs senaste rekommendationer har hämtats och utgjort studiens urval. Data har analyserats med hjälp av en strukturell ekvationsmodell och en stiganalys. Resultatet indikerar att det finns positiva samband mellan diversitet i styrelsen, vad gäller utbildning och kön, och innovativa företag. Vidare pekar studien på samband mellan innovativa företag och redovisning av samtliga sociala aspekter utom produktansvar. De starkaste sambanden finns mellan redovisning av de olika sociala aspekterna i hållbarhetsredovisningen. Den medierande effekten av innovativa företag är lägre i studien än förväntat. / The purpose of this study is to describe and statistically analyse the relationship between the board diversity and CSD (corporate social disclosure) with innovative firms as mediating variable. As a CSD contains several categories this study focuses on the social aspects: product responsibility, labour practices and decent work, society and human rights. In order to achieve the study's purpose, a quantitative study with deductive approach has been carried out. Data have been collected from the GRI (Global reporting initiative) database in which atotal of 202 multinational firms, which have outlined their CSD according to the most recent recommendations made by GRI, have been derived and thereby formed the study's sample. Data have been analysed by means of a structural equation model and a path analysis. The result indicates that there is a positive relation between board diversity, in terms of education and gender, and innovative firms. Furthermore, the study indicates a relation between innovative firms and CSD regarding all social aspects except product responsibility. Thestrongest relation exists between the various social aspects in the CSD. The mediating effect of innovative firms is lower than expected in the study.
47

De la grève de l'amiante au lobby pro-chrysotile : la question de l'amiante chez les syndicats québécois de l'amiante, 1973-1983

Marier, Micheline 04 1900 (has links)
Au début des années 1970, les travailleurs de l'amiante de Thetford Mines et d'Asbestos ont entrepris un combat pour assainir leurs milieux de travail et leurs villes, dans lesquelles les mines étaient imbriquées. À Thetford Mines, ils ont mené une longue grève de sept mois et demi qui a conduit à la mise sur pied du Comité d'étude sur la salubrité dans l'industrie de l'amiante, puis, avec l'élection du jeune Parti québécois, à la Loi sur la santé et la sécurité du travail qui introduisait les principes de l'élimination des dangers à la source et de la participation des travailleurs à son application. La crédibilité de leurs syndicats s'en trouvait renforcée. Mais bientôt la montée d'un mouvement international visant à bannir l'amiante et la crise économique du début des années 1980 allaient porter un dur coup à l'industrie et entrainer un déclin que rien ne pourrait arrêter. Les travailleurs miniers, qui s'étaient unis contre leurs employeurs et parfois contre l'État dans leur combat pour la santé, s'allièrent dès lors à leurs entreprises et aux pouvoirs publics pour promouvoir le minéral et tenter de préserver leurs emplois et la vitalité de leurs régions. Ils n'ont jamais envisagé l'arrêt de la production d'amiante car ils ont toujours considéré qu'il est possible d'en maitriser les risques et ils défendirent bec et ongles leur produit en arguant du caractère sécuritaire de ses utilisations modernes, malgré un consensus international grandissant à l'encontre de cette thèse. / The asbestos workers in the cities of Thetford Mines and Asbestos launched a campaign for better working conditions and healthier living conditions despite the entanglement of the mines in the heart of their cities, in the early 1970s. The unions in Thetford Mines together led a long, seven-and-a-half month strike, which culminated with the establishment of a committee on hygiene in the asbestos industry (Comité d’étude sur la salubrité dans l’industrie de l’amiante), and then, with the election of the young Parti Québécois, with a new occupational safety and health law which implemented the principles of eliminating dangers at their source, as well as that of worker participation in the endeavour. The asbestos unions had become credible political players. But the rise of an international movement to ban asbestos, along with the economic crisis of the early 1980s, dealt a crushing blow to the industry from which it would never recover. The miners, who had come together to take on their employers - and the government in some cases – to better their health, soon sided with industry and the public authorities to promote asbestos as a way to preserve their jobs and the life of their surrounding areas. They had never considered ceasing asbestos production because they believed the hazards could be controlled, and they persisted in their steadfast defense of the safety of the product even as an international consensus formed against this thesis.
48

Hydrate crystal structures, radial distribution functions, and computing solubility

Skyner, Rachael Elaine January 2017 (has links)
Solubility prediction usually refers to prediction of the intrinsic aqueous solubility, which is the concentration of an unionised molecule in a saturated aqueous solution at thermodynamic equilibrium at a given temperature. Solubility is determined by structural and energetic components emanating from solid-phase structure and packing interactions, solute–solvent interactions, and structural reorganisation in solution. An overview of the most commonly used methods for solubility prediction is given in Chapter 1. In this thesis, we investigate various approaches to solubility prediction and solvation model development, based on informatics and incorporation of empirical and experimental data. These are of a knowledge-based nature, and specifically incorporate information from the Cambridge Structural Database (CSD). A common problem for solubility prediction is the computational cost associated with accurate models. This issue is usually addressed by use of machine learning and regression models, such as the General Solubility Equation (GSE). These types of models are investigated and discussed in Chapter 3, where we evaluate the reliability of the GSE for a set of structures covering a large area of chemical space. We find that molecular descriptors relating to specific atom or functional group counts in the solute molecule almost always appear in improved regression models. In accordance with the findings of Chapter 3, in Chapter 4 we investigate whether radial distribution functions (RDFs) calculated for atoms (defined according to their immediate chemical environment) with water from organic hydrate crystal structures may give a good indication of interactions applicable to the solution phase, and justify this by comparison of our own RDFs to neutron diffraction data for water and ice. We then apply our RDFs to the theory of the Reference Interaction Site Model (RISM) in Chapter 5, and produce novel models for the calculation of Hydration Free Energies (HFEs).
49

On magnetic amplifiers in aircraft applications

Austrin, Lars January 2007 (has links)
<p>In the process of designing an electric power supply system for an aircraft, parameters like low weight and low losses are important. Reliability, robustness and low cost are other important factors. In the Saab Gripen aircraft, the design of the primary power supply of the electric flight control system was updated by exchanging a switching transistor regulator to a magnetic amplifier (magamp). By introducing a magamp design, weight was saved and a more reliable power supply system at a lower cost was achieved.</p><p> In this particular case, with the power supply of the electric flight control system in the Saab Gripen fighter, advantage could be taken of a specific permanent magnet generator (PM-generator). The frequency of the generator offered the perfect conditions for a magamp controller. A key parameter in designing magnetic amplifiers (magamps) is low losses. New amorphous alloys offer new possibilities of the technique in designing magnetic amplifiers, because of their extremely low losses.</p><p> The core losses are evaluated by studying the equations and diagrams specifying the power losses. The core losses are evaluated and compared with the copper losses in the process of optimizing low weight and low losses. For this an engineering tool is developed and demonstrated.</p><p> Evaluations of the hysteresis characteristics for the magnetic alloys, as well as modeling and simulation of the core losses, are presented in this work. The modeling of the core losses includes hysteresis losses, eddy current losses and excess losses as well as copper losses. The losses are studied dynamically during realistic operational conditions. The model can be used for any generic analysis of hysteresis in magnetic circuits. Applications of magnetic amplifiers in aircrafts have been demonstrated to be a feasible alternative</p>
50

On magnetic amplifiers in aircraft applications

Austrin, Lars January 2007 (has links)
In the process of designing an electric power supply system for an aircraft, parameters like low weight and low losses are important. Reliability, robustness and low cost are other important factors. In the Saab Gripen aircraft, the design of the primary power supply of the electric flight control system was updated by exchanging a switching transistor regulator to a magnetic amplifier (magamp). By introducing a magamp design, weight was saved and a more reliable power supply system at a lower cost was achieved. In this particular case, with the power supply of the electric flight control system in the Saab Gripen fighter, advantage could be taken of a specific permanent magnet generator (PM-generator). The frequency of the generator offered the perfect conditions for a magamp controller. A key parameter in designing magnetic amplifiers (magamps) is low losses. New amorphous alloys offer new possibilities of the technique in designing magnetic amplifiers, because of their extremely low losses. The core losses are evaluated by studying the equations and diagrams specifying the power losses. The core losses are evaluated and compared with the copper losses in the process of optimizing low weight and low losses. For this an engineering tool is developed and demonstrated. Evaluations of the hysteresis characteristics for the magnetic alloys, as well as modeling and simulation of the core losses, are presented in this work. The modeling of the core losses includes hysteresis losses, eddy current losses and excess losses as well as copper losses. The losses are studied dynamically during realistic operational conditions. The model can be used for any generic analysis of hysteresis in magnetic circuits. Applications of magnetic amplifiers in aircrafts have been demonstrated to be a feasible alternative / QC 20101103

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