The growing need of energy worldwide has lead to an increasing demand for alternative sources of power generation. Thermoelectric materials are one of the ‘green energy sources’ which convert directly heat into electricity, and vice–versa. The efficiency of this conversion is dependent on ‘figure of merit’ (z T), which depends on the material’s Seebeck coefficient (S), electrical resistivity (ρ) and thermal conductivity (κ) through the relation z T=S2T/ρκ, where T is the temperature. High values of z T lead to high efficiency, and therefore, z T must be maximized. Lead telluride is well–established thermoelectric material in the temperature range 350 K and 850 K. The aim of this thesis is to improve the z T of the material by adopting two different approaches – (i) doping/alloying and (ii) introducing additional interfaces in bulk i.e. having two phase PbTe. In this thesis, first an introduction about the thermoelectric phenomenon is given, along with the material parameters on which z T depends. A survey of literature associated with PbTe is done and the current status of thermoelectric devices is summarized briefly. This is followed by a description of the synthesis procedure and the measurement techniques adopted in this work. The first approach is the conventional alloying and doping of the material by which carrier concentration of the material is controlled so that maximum power factor Sρ2 is achieved and a simultaneous reduction of thermal conductivity takes place by mass fluctuation scattering. Under this, two systems have been studied. The first system is PbTe1−ySey alloys doped with In (nominal composition: Pb0.999In0.001Te1−ySey, y=0.01, 0.05, 0.10, 0.20, 0.25, 0.30). The compounds were single phase and polycrystalline. Lattice constants obtained from Rietveld refinement of X–ray diffraction (XRD) data showed that Vegard’s law was followed, indicating solid solution formation between PbTe and PbSe. Compositional analysis showed lower indium content than the nominal composition. Temperature dependent Seebeck coefficient showed all the samples to be n–type while Pisarenko plots showed that indium did not act as a resonant dopant. Electrical resistivity increased with temperature, while mobility vs T fitting showed a mixed scattering mechanism of acoustic phonon and ionized impurity scattering. Thermal conductivity followed a T1 dependence, which indicated acoustic phonon scattering. At high temperature, slight bipolar effect was observed, which showed the importance of control-ling carrier concentration for good thermoelectric properties. A z T of 0.66 was achieved at 800 K. The second alloy studied under this approach was Mn doped Pb1−ySnyTe alloy (nominal composition Pb0.96−yMn0.04SnyTe (y=0.56, 0.64, 0.72, 0.80)). All the samples followed Vegard’s law, showing formation of complete solid solution between PbTe and SnTe. Microstructure analysis showed grain size distribution of <1 µm to more than 10 µm. Seebeck coefficient showed all samples were p-type and the role of two valence band conduction in p–type PbTe based materials. Electrical resistivity showed a de-crease possibly due to (i) large carrier concentration or (ii) increased mobility due to Mn2+ ions. Thermal conductivity decreased systematically with decreasing Sn content. Bipolar effect was observed at high temperatures. Accordingly, the highest z T of 0.82 at 720 K was obtained for the sample with Sn (y=0.56) content due to optimum carrier concentration and maximum disorder. The second approach of having additional interfaces in bulk focuses on reducing thermal conductivity by scattering phonons. Under this approach, three systems were studied. The first system is PbTe with bismuth (Bi) secondary phase. The XRD and Ra-man studies showed that bismuth was not a dopant in PbTe, while micrographs showed micrometer–sized Bi secondary phase dispersed in bulk of PbTe. Reduction in Seebeck coefficient showed possible hole donation across PbTe–Bi interfaces, while electrical re-sistivity and thermal conductivity showed that the role of electrons at the interfaces was more important than phonons for the present bismuth concentrations. For the parent PbTe, z T of 0.8 at 725 K was reached, which, however decreased for bismuth added samples. The second system studied under the two phase approach was indium (In) added PbTe. Indium was not found to act as dopant in PbTe, while micrometer sized indium phase was found in PbTe bulk. A decrease in the electronic thermal conductivity ac-companied by a simultaneous increase of the electrical resistivity and Seebeck coefficient throughout the measurement range indicated increased scattering of electrons at PbTe-In interfaces. Higher values of the lattice thermal conductivity showed that the PbTe–In interfaces were ineffective at scattering phonons, which was initially expected due to the lattice mismatch between PbTe and In. For PbTe with 3 at. % In phase, z T value of 0.78 at 723 K was achieved. Under the two phase approach, as a comparative study, PbTe with both micrometer sized Bi and In phases together was prepared, in which no improvement in z T was found. A comparison of both the approaches showed that the alloying approach is better than the two–phase approach. This is because micrometer sized secondary phase scatter the electrons more than the phonons, leading to adverse effect on the transport coef-ficients, and hence, on z T. Alloying, on the other hand, is more beneficial in reducing thermal conductivity by mass fluctuation scattering, along with a simultaneous reduction of electrical resistivity.

Avec l’avènement de la prochaine génération de télescope de plus de 30m de diamètre, il devient primordial de réduire le coût des observations et d’améliorer leur rendement scientifique. De plus il est essentiel de construire ces instruments sur des sites disposant d’une qualité optique maximale. J’ai donc essayé, au cours de ma thèse, de développer un outil fiable, facile d’utilisation et économique permettant de satisfaire ces exigences. J’ai donc utilisé le modèle de prévision météorologique Weather Research and Forecasting et le modèle de calcul de la turbulence optique Trinquet-Vernin pour prédire, plusieurs heures à l’avance, les conditions optiques du ciel tout au long de la nuit. Cette information permettrait d’améliorer la gestion du programme d’observation, appelée "flexible scheduling", et ainsi de réduire les pertes dues à la variation des conditions atmosphériques. Les résultats obtenus et les améliorations apportées au modèle WRF-TV lui permettent de présenter un bon accord entre les mesures et les prévisions ce qui est prometteur pour une utilisation réelle. Au delà de cette gestion, nous avons voulu créer un moyen d’améliorer la recherche et le test de sites astronomiquement intéressants. Nous avons donc définit un paramètre de qualité qui prend en compte les conditions météorologiques et optiques. Ce paramètre a été testé au-dessus de l’île de La Palma aux Canaries et a montré que l’Observatorio del Roque de los Muchachos est situé au meilleur emplacement de l’île. Enfin nous avons créé une routine d’automatisation du modèle WRF-TV afin d’avoir un outil opérationnel fonctionnant de manière autonome. / With the next generation of extremely large telescope having mirror with a diameter larger than 30m, it becomes essential to reduce the cost of observations and to improve their scientific efficiency. Moreover it is fundamental to build these huge infrastructures in location having the best possible optical quality. The purpose of my thesis is to bring a solution easier and more economical than before. I used the Weather Research and Forecasting (WRF) model and the Trinquet-Vernin parametrization, which computes the values of the optical turbulence, to forecast a couple of hours in advance the evolution of the sky optical quality along the coming night. This information would improve the management of observation program, called "flexible scheduling", and thereby reduce losses due to the atmospheric variations. Our results and improvements allow the model us WRF-TV to have a good agreement between previsions and in-situ measurements in different sites, which is promising for a real use in an observatory. Beyond the flexible scheduling, we wanted to create a tool to improve the search for new sites or site testing for already existing sites. Therefore we defined a quality parameter which takes into account meteorological conditions (wind, humidity, precipitable water vapor) and optical conditions (seeing, coherence time, isoplanatic angle). This parameter has been tested above La Palma in Canary island showing that the Observatorio del Roque de los Muchachos is located close to the best possible location of the island. Finally we created an automated program to use WRF-TV model in order to have an operational tool working routinely.

The author is reviewing the research that E. Kuruczová demonstrated in her diploma thesis called The effect of social organization of games on the orientation in their moral dimension. The main goal of the diploma thesis Kuruczová developed another contribution to Piaget's theory of the development of moral reasoning of school-age children. Piaget's empirical data suggested that social organizations could influence orientation in their moral dimensions. Kuruczová found that in her 180 children from one school (aged 1st - 9th grade) the development of orientation in the moral dimension of the game King of Deer Hunters (organized as a competition) performs ahead of the development of orientation in the moral dimension of the game Hot Potato (organized as a collaboration). Furthermore, in the research, children of Kuruczová think about the stories of unjust play situations organized by "Mrs. Teacher". Even the youngest and unoriented did not argue the evaluation of the situation as a fair authority of the teacher - which, according to Piaget's theory, could assume the key role of the criterion of obedience of authority in the heteronomous understanding of the criteria of moral evaluation. This thesis therefore answers the question of whether it can replicate these findings. Unlike Kuruczová,...

South African affirmative action law in the workplace is in its infancy. Yet some concepts in this context have already proven to be unclear or in need of interpretation, or are lacking. This thesis focuses on the beneficiaries of affirmative action in employment law. The Employment Equity Act (EEA) creates `designated groups' &#9472; black people, women and people with disabilities &#9472; as the beneficiaries of affirmative action. It lays down two requirements for beneficiaries of affirmative action which are investigated: (a) beneficiaries must be from the designated groups - in this regard, the question that arises is whether, having been categorised as disadvantaged, persons are presumed to be de facto disadvantaged and entitled to benefit from affirmative action, or whether further evidence of actual past disadvantage is required; and (b) beneficiaries must be `suitably qualified'. In addition, citizenship as a third requirement for beneficiaries of affirmative action has been mooted in case law. This is evaluated against modern interpretation theory, the Constitution and discrimination law. Against the background of a comparative investigation of the position in the US and Canada, and under international law, specific findings and recommendations are made in respect of South African affirmative action law. These relate to the interpretation of the concept `disadvantage', to a pragmatic and contextualised approach to the notion `degrees of disadvantage', to the recognition of the concept `multiple disadvantage', to the clarification of the meaning and application of the concept `suitably qualified' in a code of good practice, and to a policy decision by government to ensure that affirmative action measures apply mainly to South African citizens who otherwise qualify to benefit. To this end, certain amendments to the EEA, its regulations and codes of good practice are proposed with the aim of ensuring that affirmative action measures in fact benefit those intended by the EEA. Some projections are made to indicate the way forward for affirmative action in South Africa. / Jurisprudence / LL.D.

South African affirmative action law in the workplace is in its infancy. Yet some concepts in this context have already proven to be unclear or in need of interpretation, or are lacking. This thesis focuses on the beneficiaries of affirmative action in employment law. The Employment Equity Act (EEA) creates `designated groups' &#9472; black people, women and people with disabilities &#9472; as the beneficiaries of affirmative action. It lays down two requirements for beneficiaries of affirmative action which are investigated: (a) beneficiaries must be from the designated groups - in this regard, the question that arises is whether, having been categorised as disadvantaged, persons are presumed to be de facto disadvantaged and entitled to benefit from affirmative action, or whether further evidence of actual past disadvantage is required; and (b) beneficiaries must be `suitably qualified'. In addition, citizenship as a third requirement for beneficiaries of affirmative action has been mooted in case law. This is evaluated against modern interpretation theory, the Constitution and discrimination law. Against the background of a comparative investigation of the position in the US and Canada, and under international law, specific findings and recommendations are made in respect of South African affirmative action law. These relate to the interpretation of the concept `disadvantage', to a pragmatic and contextualised approach to the notion `degrees of disadvantage', to the recognition of the concept `multiple disadvantage', to the clarification of the meaning and application of the concept `suitably qualified' in a code of good practice, and to a policy decision by government to ensure that affirmative action measures apply mainly to South African citizens who otherwise qualify to benefit. To this end, certain amendments to the EEA, its regulations and codes of good practice are proposed with the aim of ensuring that affirmative action measures in fact benefit those intended by the EEA. Some projections are made to indicate the way forward for affirmative action in South Africa. / Jurisprudence / LL.D.

The operation of electric grids depends on the balance between the electric generation and the demand. In France, the Transmission System Operator, RTE, is responsible for the stability and the security of the grid. Today, the electric generation follows the variations of the demand. However, environmental concerns prompt to develop new strategies and policies for Energy Transition. The development of Smart Grids, the uncertain future of nuclear generation, the massive integration of renewable sources are the focus of those. Furthermore, renewable energies generation is intermittent and can not be controlled. The current strategy for the balance between generation and demand is challenged. The electric grid has to be readjusted by adding more electric flexibility to ensure its stability. The electric flexibility is usually associated to storage technologies as batteries or pumping stations. A state of art review is used to define this notion and to evaluate the technological and economic maturity of different electric flexibility vectors. The following report is based on a selection of prospective scenarios, development plans already launched in France, proposing a significant share of renewable energies in a future energy mix and current French energy data. Two studies were carried out : one at a regional level, for Bretagne and one at national level for France. An evaluation at 2050 is carried out to determine the load factors of intermittent energies, consumption and residual demand in Bretagne. On the basis of these prospective estimates, a need for electric flexibility can be determined for the Bretagne region. This first study highlights an issue related to future needs for electric flexibility. However, since the balance between production and consumption is achieved at a national level, a second study on France is necessary. The French need for electric flexibility is then estimated through a linear optimization that evaluates the energy production required to achieve a generation/consumption balance taking into account energy sources merit order. / Det franska elnätets funktion beror på balansen mellan elproduktionen och efterfrågan. Transmissionssystemoperatören, RTE, ansvarar för nätets stabilitet och säkerhet. Idag följer den elektriska generationen variationerna i efterfrågan. Miljömässiga frågor är emellertid snabba för att utveckla nya strategier och strategier för energiövergång. Utvecklingen av Smart Grids, den osäkra framtiden för kärnkraftsproduktion, den massiva integrationen av förnybara källor är deras fokus. Vidare är generering av förnybara energikällor intermittent och kan inte kontrolleras. Den nuvarande strategin för balans mellan produktion och efterfrågan utmanas. Elnätet måste justeras genom att lägga till mer elektrisk flexibilitet för att säkerställa stabiliteten. Den elektriska flexibiliteten är vanligtvis förknippad med lagringsteknik som batterier eller pumpstationer. En allmänt erkända tekniska används för att definiera denna uppfattning och att utvärdera den tekniska och ekonomiska mognaden hos olika elektriska flexibilitetsvektorer. Följande undersökningar grundar sig på ett urval av framtida scenarier, utvecklingsplaner som redan lanserats i Frankrike, och föreslår en betydande andel förnybara energikällor i en framtida energimix och nuvarande franska energidata. Två studier utfördes på olika perimetrar: på Bretagne-regionen och i Frankrike. En utvärdering vid 2050 utförs för att bestämma belastningsfaktorerna för intermittent energi, förbrukning och återstående efterfrågan i Bretagne. På grundval av dessa framtida uppskattningar kan ett behov av elektrisk flexibilitet bestämmas för Bretagne-regionen. Denna första studie lyfter fram ett problem som rör framtida behov av elektrisk flexibilitet. Men eftersom balansen mellan produktion och konsumtion uppnås på nationell nivå krävs en andra studie om Frankrike. Det franska behovet av elektrisk flexibilitet uppskattas sedan genom en linjär optimering som utvärderar den energiproduktion som krävs för att uppnå en generation / konsumtionsbalans med hänsyn tagen till energikällans meriteringsordning. / Le fonctionnement du réseau électrique français repose sur l’équilibre entre la production et la consommation d’électricité. Le gestionnaire du réseau de transport, RTE, est responsable de la stabilité et de la sécurité du réseau. Aujourd’hui, la production électrique s’adapte aux variations de la consommation. Cependant, des préoccupations environnementales incitent à la mise en place de nouvelles stratégies et politiques pour la transition énergétique. Le développement d’un réseau intelligent, l’avenir incertain du nucléaire et l’intégration massive d’énergies renouvelables sont au centre de celles-ci. De plus, la production électrique des énergies renouvelables s’avère intermittente et fatale. La stratégie actuelle du maintien de l’équilibre production/consommation est remise en question. Le système électrique doit être repensé en y intégrant plus de flexibilité électrique pour en garantir la stabilité. La flexibilité électrique est usuellement associée aux technologies de stockage comme les batteries électrochimiques et les STEP hydrauliques. Un état de l’art permet de définir précisément cette notion et d’évaluer la maturité technologique et économique en France de ces différents vecteurs de flexibilité électrique. L’objet des recherches suivantes est basé sur une sélection de scénarios prospectifs, de plans de développement d’ores et déjà lancés en France, proposant une part importante d’énergies renouvelables dans un futur mix énergétique et des données énergétiques actuelles françaises. Deux études ont été menées sur différents périmètres : sur la région Bretagne et sur la France entière. Une évaluation à 2050 est effectuée pour déterminer facteurs de charge des énergies intermittentes, consommation et demande résiduelle en Bretagne. A partir de ces estimations prospectives, un besoin en flexibilité peut être déterminé sur le périmètre de la Bretagne. Cette première étude permet de mettre en exergue une problématique liée aux futurs besoins de flexibilité électrique. Cependant, l’équilibre entre production et consommation étant réalisé à un niveau national, une seconde étude sur le périmètre français est nécessaire. Le besoin français en flexibilité est alors estimé par le biais d’une optimisation linéaire qui évalue la production énergétique nécessaire pour obtenir un équilibre production/consommation en tenant compte de la préséance économique.

Racial and gender inequality, as well as other forms of discrimination has been a part of the South African, American and Indian histories for a very long time. Even today racial disparity is still very evident in the South African and American societies whilst discrimination based on caste is still prevalent in the Indian society. This is illustrated by continued racial discrimination and the remaining signs of societal segregation. Due to continuing disparities amongst the people, it became necessary to implement affirmative action programmes. Focusing in particular on education and jobs, affirmative action policies require active measures to be taken to ensure that blacks and other minorities enjoy the same opportunities for career advancement and school admissions that had been the nearly exclusive province of whites in SA and the USA, or for the forward castes in India. Affirmative action has been both praised and denounced, as an answer to racial inequality. One of the key issues that arise when affirmative action is discussed is whether or not affirmative action in fact promotes equality and atones for past prejudices. Another concern is whether the current affirmative action policy is the right policy to use. The issues surrounding affirmative action seems to be universal as are the circumstances. Perhaps the most widespread similarity among the programmes in these very different countries has been that group preferences and quotas are almost always discussed. The debate on affirmative action exists because it is a very divisive issue and it affects different groups of people in different ways, and some groups or persons seemingly benefit more from affirmative action than other persons or groups. In addition, it causes people to be classified into groups, and at the same time, strives to break down group barriers. It is an issue that is difficult to resolve because people have varied ideas about how the problems of racial inequality and historical discrimination should be addressed / Jurisprudence / LLD

Plasmonic properties and the related novel applications are studied on various types of metallic nano-structures in one, two, or three dimensions. For 1D nanostructure, the motion of free electrons in a metal-film with nanoscale thickness is confined in its normal dimension and free in the other two. Describing the free-electron motion at metal-dielectric surfaces, surface plasmon polariton (SPP) is an elementary excitation of such motions and is well known. When further perforated with periodic array of holes, periodicity will introduce degeneracy, incur energy-level splitting, and facilitate the coupling between free-space photon and SPP. We applied this concept to achieve a plasmonic perfect absorber. The experimentally observed reflection dip splitting is qualitatively explained by a perturbation theory based on the above concept. If confined in 2D, the nanostructures become nanowires that intrigue a broad range of research interests. We performed various studies on the resonance and propagation of metal nanowires with different materials, cross-sectional shapes and form factors, in passive or active medium, in support of corresponding experimental works. Finite- Difference Time-Domain (FDTD) simulations show that simulated results agrees well with experiments and makes fundamental mode analysis possible. Confined in 3D, the electron motions in a single metal nanoparticle (NP) leads to localized surface plasmon resonance (LSPR) that enables another novel and important application: plasmon-heating. By exciting the LSPR of a gold particle embedded in liquid, the excited plasmon will decay into heat in the particle and will heat up the surrounding liquid eventually. With sufficient exciting optical intensity, the heat transfer from NP to liquid will undergo an explosive process and make a vapor envelop: nanobubble. We characterized the size, pressure and temperature of the nanobubble by a simple model relying on Mie calculations and continuous medium assumption. A novel effective medium method is also developed to replace the role of Mie calculations. The characterized temperature is in excellent agreement with that by Raman scattering. If fabricated in an ordered cluster, NPs exhibit double-resonance features and the double Fano-resonant structure is demonstrated to most enhance the four-wave mixing efficiency.

Racial and gender inequality, as well as other forms of discrimination has been a part of the South African, American and Indian histories for a very long time. Even today racial disparity is still very evident in the South African and American societies whilst discrimination based on caste is still prevalent in the Indian society. This is illustrated by continued racial discrimination and the remaining signs of societal segregation. Due to continuing disparities amongst the people, it became necessary to implement affirmative action programmes. Focusing in particular on education and jobs, affirmative action policies require active measures to be taken to ensure that blacks and other minorities enjoy the same opportunities for career advancement and school admissions that had been the nearly exclusive province of whites in SA and the USA, or for the forward castes in India. Affirmative action has been both praised and denounced, as an answer to racial inequality. One of the key issues that arise when affirmative action is discussed is whether or not affirmative action in fact promotes equality and atones for past prejudices. Another concern is whether the current affirmative action policy is the right policy to use. The issues surrounding affirmative action seems to be universal as are the circumstances. Perhaps the most widespread similarity among the programmes in these very different countries has been that group preferences and quotas are almost always discussed. The debate on affirmative action exists because it is a very divisive issue and it affects different groups of people in different ways, and some groups or persons seemingly benefit more from affirmative action than other persons or groups. In addition, it causes people to be classified into groups, and at the same time, strives to break down group barriers. It is an issue that is difficult to resolve because people have varied ideas about how the problems of racial inequality and historical discrimination should be addressed / Jurisprudence / LLD

This study explored the role of school-based teacher financial incentives on student academic achievement. Despite great efforts made by Zimbabwean government towards improving the education system in terms of infrastructure development and increasing number of schools, prior and after 1980, not much attention had been paid to the role of teachers’ extra-financial incentives on enhancing teacher motivation which leads to student achievement in and outside classroom situation. Extra-financial incentives differ from government to government depending on the revenue base and political will by such governments to support these teacher incentives programmes. In developed countries, respective governments pay different teacher incentives while in developing countries, parents/guardians or School Development Committees (SDCs) shoulder the burden. This study contented that one of the ways to improve student achievement has been payment of school-based teacher incentives to supplement teachers’ low salaries. While the need to adequately compensate teachers had been a worldwide phenomenon, this is in contrast to Zimbabwean experience after 2014, when Government of National Unity (GNU) came to an end. Zimbabwean government banned payment of teacher incentives under unclear reasons which were widely purported to be political. This research adopted a qualitative approach and as such, collection of primary and secondary data were done using multiple data collection techniques. Techniques included interviews with key informants, focus group discussions and open ended questionnaires in selected secondary schools. Results from this study revealed that improving teacher motivation through school-based incentives had been central to improved student achievement. In schools where teacher incentive system was practiced pass-rates increased, with a sudden decline when teacher incentives were banned. Banning or lack of properly designed incentive systems, where teachers were consulted, was seen as negatively affecting student achievement in selected secondary schools of Makoni District. / Educational Foundations / D. Ed. (Socio-Education)