Gegenstand dieser Arbeit ist die Entwicklung und Untersuchung eines Aufbereitungsprozesses zur Gewinnung von Bitumen aus kanadischem Athabasca Ölsand, der im Tagebau gewonnen wurde. Es wird ein mechanisch-thermisches Verfahren zur Fest-Flüssig-Trennung eingesetzt. Dabei handelt es sich um vier Schritte: (1) Suspendierung des Ölsandes mit den organischen Lösungsmitteln, Toluol und n-Heptan, (2) Filterkuchenbildung, (3) Waschung des Filterkuchens mit Wechsel der Waschflüssigkeiten (gradierte Waschung) und (4) Dampfbeaufschlagung. Der Prozess stellt eine Alternative zur herkömmlichen Heißwasser-extraktion des Ölsandes dar. Die Nachteile der Heißwasserextraktion sind ökologische Probleme, ein hoher Energie- und Frischwasserbedarf. Die Ziele des Alternativprozesses sind die Minimierung des Wasser- und Energiebedarfs, Vermeidung schädlicher Abfallstoffe sowie die Maximierung der Bitumenausbeute. Als Produkte sollen feststofffreies Bitumen und rückstandsfreier, deponierbarer Feststoff gewonnen werden.

This thesis explores and describes the relationship between emotional intelligence, job satisfaction and job self-efficacy. The sample was collected between 2007 and 2010 and consists of 1336 South Africans within the workplace. Trait emotional intelligence was assessed using the Trait Emotional Intelligence Questionnaire (TEIQue), while job satisfaction and job self-efficacy were assessed from the biographical questions asked during the TEIQue assessment process. The first hypothesis investigated whether there is a statistically significant relationship between job satisfaction and trait emotional intelligence. A relationship was found that is statistically, but not practically, significant. The second hypothesis centred on the relationship between job self-efficacy and emotional intelligence, with statistically significant results (p<0.001), and a weaker relationship than the one found between job satisfaction and scores on the TEIQue. The third hypothesis, investigating a possible interaction effect between job satisfaction and job self-efficacy, was rejected. In addition to the study’s three hypotheses, exploratory IRT analysis was conducted on a section of the TEIQue items in order to further explore the functioning of the test within the South African context. Findings suggest that there is a relationship between the constructs within the study, but that this relationship is more complex than first assumed, being affected by issues such as social desirability and central tendency bias. / Psychology / M.A. (Psychology)

Aim of this thesis is the usage of the open-graded asphalt concrete filled with a special cement grout in the road structures. Thesis defines the main concrete properties and explains related legislation and norms that apply. In addition, laboratory design of asfalt mixtures and a tree kind mortal filler and possibilities of mortal filler pigmentation are dealth with. Finally, thesis evaluates the results from various laboratory tests that were performed on the specimens made from final mixtures.

The discovery of metamaterials has led to major advances in different fields of physics including optics, microwave engineering and acoustics. Specific to theoretical electromagnetism, the introduction of metamaterials have led to the development of negative-index materials (NIMs) with simultaneous negative permittivity and negative permeability with backward-wave propagation. In recent studies, exact analytical solutions for wave propagation from a step/graded-index interface between a right-handed material (RHM) and a left-handed material (LHM) have been obtained. This study attempts to provide numerical validation of the analytical solutions obtained by Dalarsson et al. by using the simulation tool CST. An square-SRR/strip-wire unit element was designed, with real part of relative permittivity equal to -1.96 and real part of relative permeability equal to -1.01. Such unit elements were orderly structured to produce a NIM structure. Furthermore, a positive-index material (PIM) structure was produced by reversing the sign of the material properties of the NIM. Both the results for the step- and graded-index interfaces have shown to possess backward-wave propagation for a normal incidence angle. The graded-index interface profiles have a more smooth and continuous wave propagation between the materials, which counteracts the effects of discontinuous material transitions present in step-index interface profiles. However, because the results of the present study were considerably affected by unwanted field effects, the analytical solutions are only qualitatively validated, and not validated in terms of their numerical accuracy. / Upptäckten av metamaterial har lett till stora framsteg inom olika fysikområden inklusive optik, mikrovågsteknik och akustik. Specifikt för teoretisk elektromagnetism, har introduktionen av metamaterial lett till utvecklingen av negativa indexmaterial (NIM) med samtidig negativ permittivitet och negativ permeabilitet med bakåtvågsutbredning. I nyligen genomförda studier, har exakta analytiska lösningar för vågutbredning över ett steg-/graderat- indexgränssnitt mellan ett högerhänt material (RHM) och ett vänsterhänt material (LHM) erhållits. Denna studie försöker tillhanda-hålla numerisk validering, med hjälp av simuleringsverktyget CST, av de analytiska lösningar som erhållits av Dalarsson et al. En square-SRR/strip-wire enhetselement designades, med realdelen av relativ permittivitet lika med -1,96 och realdelen av relativ permeabilitet lika med -1,01. Sådana enhetselement strukturerades för att producera en materialstruktur med negativt index. Dessutom producerades en materialstruktur med positivt index (PIM) genom att vända tecknet av materialegenskaperna hos det negativa indexmaterialet (NIM). Både resultaten för steggränssnittet och det graderade indexgränssnittet har visat sig ha bakåtvågutbredning för vinkelrätt infall. De graderade indexgränssnittsprofilerna har en mer jämn och kontinuerlig vågutbredning mellan materialen, vilket motverkar effekterna av diskontinuerliga materialövergångar som finns i stegindexgränssnittsprofiler. Men eftersom resultaten av den aktuella studien påverkades avsevärt av oönskade fälteffekter, har de analytiska lösningarna validerats endast kvalitativt och valideras inte i termer av deras numeriska noggrannhet.

Das 1K- und das 2K-Spritzgießverfahren dienen zur Herstellung thermoplastischer Sandwichstrukturen, deren Deck- und Kernschicht aus einer kurzglasfaserverstärkten Polypropylen-Folie sowie entweder kompaktem oder geschäumtem Polypropylen besteht. Zudem erfolgt die Herstellung der Schäume durch das CELLMOULD®-Verfahren mit einem physikalischen Treibmittel. Eine geeignete kurzfaserverstärkte PP-Folie wird aufgrund ihrer mikroskopischen, rheologischen und mechanischen Eigenschaften ausgewählt. Beim Schaumspritzgießen ermittelt die Drei-Wege-ANOVA den Einfluss der Werkzeugtemperatur, der Eingasungsmenge und der Einspritzgeschwindigkeit auf die Dichte sowie die Zelldichte und die Zellgröße der eingespritzten Schäume. Funktional gradierte Sandwichstrukturen lassen sich durch die Mikrostruktur-untersuchung evaluieren. Die mechanischen und spezifischen mechanischen Eigenschaften der eingespritzten Proben werden in der Arbeit durch die Biegeprüfung bestimmt. Die Ergebnisse zeigen, dass sich faserverstärkte konventionelle PP-Folien mit 30 Gew.-% am besten für die Deckschichten eignen. Beim Schaumspritzgießen beeinflusst lediglich die Werkzeugtemperatur die Zelldichte und die Zellgröße. Funktional gradiertes Material ergibt sich bei der Sandwichstruktur, die durch 1K-Spritzgießen hergestellt wird. Aufgrund des Vorhandenseins einer geschäumten Lage, kompakter Lagen und kurzglasfaserverstärkter Lagen findet die Gradierung sich von der Mitte bis zu den Rändern der Proben statt. Das Vorhandensein von Schaumstrukturen verringert den Biegemodul und die Biegefestigkeit. Die Biegedehnung bei maximaler Biegespannung nimmt signifikant mit den vorhandenen Glasfasern ab. Die Sandwichstrukturen führen lediglich zur Erhöhung des Biegemoduls und der Biegefestigkeit gegenüber kompaktem und geschäumtem PP. Die Biegedehnung bei maximaler Biegespannung verhält sich bei den Sandwichstrukturen umgekehrt zum Biegemodul und der Biegefestigkeit. Beim Vergleich mittels unterschiedlicher Spritzgießverfahren produzierter Sandwichstrukturen haben die durch das 1K-Spritzgießverfahren hergestellten Proben einen niedrigeren Biegemodul und eine geringere Biegefestigkeit als die durch das 2K-Spritzgießverfahren produzierten. Jedoch zeigen die Sandwichstrukturen aus dem 1K-Spritzgießverfahren mit geschäumtem Kern den höheren spezifischen Biegemodul und die höhere spezifische Biegefestigkeit in Y-Richtung im Vergleich zu jenen aus dem 2K-Spritzgießverfahren. Außerdem weisen die verschiedenen Versagensarten der Sandwichstrukturen bei der Biegeprüfung und der Bestimmung der interlaminaren Scherfestigkeit keine Delamination zwischen Deck- und Kernschicht auf. Bei der Berechnung durch den modifizierten Gonzales-Ansatz und die Paralleltheorie zeigt sich, dass der E-Modul der Schäume und der Sandwichstrukturen fast identisch mit jenem aus den Experimenten ist. Allerdings ist die Berechnung der faserverstärkten Proben nicht möglich, daher wird der E-Modul aus den Experimenten verwendet, um die Durchbiegung im Rahmen einer Balkentheorie zu bestimmen. Die nahezu identische Durchbiegung aus dem Experiment und der Berechnung lässt sich auch durch die Euler-Bernoulli-Balkentheorie nachweisen. Die Arbeit zeigt auf, dass die Sprünge in der Steifigkeit und Festigkeit in jeder Lage von 1K-und 2K-spritzgegossenen Sandwichstrukturen abnehmen. Auf diese Weise lässt sich die Vermeidung der Delamination zwischen Deck- und Kernschicht erreichen. Die Dichte und die Materialmenge der Sandwichstrukturen reduzieren sich ohne signifikante Abnahme des spezifischen Biegemoduls und der spezifischen Biegefestigkeit. Mit der Verwendung von mechanischen Eigenschaften von Teilkomponenten der Sandwich-struktur können die Biegeeigenschaften der gradierten Sandwich-strukturen durch eine Berechnung vorausgesagt werden.:1 Einführung 2 Stand der Technik 3 Motivation und Ziel 4 Versuchsdurchführung 5 Ergebnisse und Diskussion 6 Zusammenfassung und Ausblick / The 1-component and 2-component injection moulding processes are employed to produce thermoplastic sandwich structures of which the skin and core layers comprise a short glass fibre-reinforced polypropylene film and either compact or foamed polypropylene, respectively. In addition, the foams are produced using the CELLMOULD® process with a physical blowing agent. A suitable short fibre reinforced PP film is selected on the basis of its microscopic, rheological and mechanical properties. In foam injection moulding, the three-way ANOVA determines the influence of the mould temperature, gas content and injection speed on the density as well as the cell density and cell size of the injected foams. Functionally graded sandwich structures can be proven by using the microstructure investigation. The mechanical properties and specific mechanical properties of the injected samples are determined by the three-point bending test. The results show that fibre-reinforced conventional PP films with 30 wt% are the most suitable for the skin layers. In the case of foam injection moulding, only the mould temperature influences the cell density and cell size of the injected foams. Functionally graded material results from the sandwich structure, which is produced by 1-component injection moulding process, because a foamed layer, compact layers and short glass fibres reinforced layers occur from the middle to the edges of these samples. The presence of foam structures reduces the flexural modulus and the flexural strength. The bending elongation at maximum bending stress decreases significantly with the existing glass fibres. The sandwich structures only increase the flexural modulus and the flexural strength compared to compact and foamed PP. The bending elongation at maximum bending stress behaves in the opposite way in the sandwich structures compared to the flexural module and the flexural strength. When comparing sandwich structures produced using different injection moulding processes, the sandwich structures produced by the 1-component injection moulding process have a lower flexural modulus and a lower flexural strength than those produced by the 2-component injection moulding process. However, the sandwich structures with foamed core from the 1-component injection moulding process show the higher specific flexural modulus and the higher specific flexural strength in Y-direction compared to those in the same direction from the 2-component injection moulding process. In addition, the various types of failure of the sandwich structures during the bending test and the determination of the interlaminar shear strength provide no delamination between the skin and core layers. The calculation suggests that the modulus of elasticity of the foams and the sandwich structures, calculated by the modified Gonzales approach and the parallel theory, respectively, is almost identical to that from the experiments. Nevertheless, the calculation of the fibres-reinforced samples cannot be achieved, hence, the modulus of elasticity of the fibres-reinforced samples from the experiments is used to determine the deflection based on a beam theory. The almost identical deflection from the experiment and the calculation can also be demonstrated by the Euler-Bernoulli beam theory.The work shows that the significant change in rigidity and strength decrease in each layer of 1-component and 2-component injection moulded sandwich structures. Thus, the avoidance of delamination between the skin and core layers can be achieved. The density and the amount of material in the sandwich structures are reduced without a significant decrease in the specific flexural modulus and the specific flexural strength. With the use of mechanical properties of subcomponents of the sandwich structure, the bending properties of the graded sandwich structures can be predicted by a calculation.:1 Einführung 2 Stand der Technik 3 Motivation und Ziel 4 Versuchsdurchführung 5 Ergebnisse und Diskussion 6 Zusammenfassung und Ausblick

Since the advent of the Internet, the number of individuals and organisations using tools such as the World Wide Web and cell phones has increased, and is continuing to grow at a rapid pace. Social media has provoked fundamentally different ways of doing business, and organisations rapidly had to get on this social media bandwagon to stay up to date with the latest market trends and ahead of the competition. Although social media is already broadly used among South African businesses, the perception regarding the use of social media as a promotional mix element has not been investigated sufficiently in South Africa. The primary purpose of this study was therefore to determine the perception of star-graded accommodation establishments, operating in the Western Cape province of South Africa, regarding the use of social media as a promotional mix element. A broad and in-depth literature review was conducted on the use of social media and social media as a probable promotional mix element. An empirical study was conducted, in which data was collected from star-graded accommodation establishments operating in the Western Cape by means of a web-based (computer-assisted) self-administered questionnaire. A quantitative approach was followed in order to satisfy the research objectives of this study. The results of this research study indicate that social media is perceived to be an instrumental marketing element in star-graded accommodation establishments and can indeed be considered an element of the promotional mix. / Business Management / MCOM (Business Management)

Since the advent of the Internet, the number of individuals and organisations using tools such as the World Wide Web and cell phones has increased, and is continuing to grow at a rapid pace. Social media has provoked fundamentally different ways of doing business, and organisations rapidly had to get on this social media bandwagon to stay up to date with the latest market trends and ahead of the competition. Although social media is already broadly used among South African businesses, the perception regarding the use of social media as a promotional mix element has not been investigated sufficiently in South Africa. The primary purpose of this study was therefore to determine the perception of star-graded accommodation establishments, operating in the Western Cape province of South Africa, regarding the use of social media as a promotional mix element. A broad and in-depth literature review was conducted on the use of social media and social media as a probable promotional mix element. An empirical study was conducted, in which data was collected from star-graded accommodation establishments operating in the Western Cape by means of a web-based (computer-assisted) self-administered questionnaire. A quantitative approach was followed in order to satisfy the research objectives of this study. The results of this research study indicate that social media is perceived to be an instrumental marketing element in star-graded accommodation establishments and can indeed be considered an element of the promotional mix. / Business Management / M. Com. (Business Management)