[ES] Las nuevas regulaciones en materia de emisiones de efecto invernadero y calidad del aire han conducido la evolución tecnológica de los motores de combustión interna durante los últimos años. Las mejoras en el proceso de la combustión, la sobrealimentación, la gestión térmica, los sistemas de post tratamiento y técnicas como la recirculación de gases de escape, han permitido que los motores de combustión interna de hoy en día sean cada vez más limpios. La adopción en Europa del nuevo ciclo de homologación WLTP, que considera un ciclo de conducción más realista que su predecesor el NEDC, así como la necesidad de evaluar las emisiones contaminantes en diferentes escenarios de temperatura ambiente y de altitud, suponen un desafío para los fabricantes a la hora de diseñar y optimizar sus motores. En este contexto, el modelado unidimensional del motor ofrece la posibilidad de desarrollar y probar diferentes soluciones con la suficiente precisión,a la vez que permite agilizar el proceso de diseño del motor y reducir los costes de éste. El objetivo de esta tesis es el de desarrollar un modelo completo de motor virtual que permita simular condiciones transitorias de régimen de giro y grado de carga, así como diferentes condiciones ambientales de presión y temperatura. Con este modelo de motor se pretende predecir las principales variables termo-fluidodinámicas en diferentes puntos del motor y las emisiones contaminantes liberadas en el escape. Por otra parte, el arranque en frío y el funcionamiento a bajas temperaturas están asociados a un mayor consumo, mayores emisiones de hidrocarburos (HC) y monóxido de carbono (CO), así como mayores emisiones de óxidos de nitrógeno (NOx) debido a la desactivación de los sistemas de recirculación de gases de escape. Para paliar estos efectos adversos, una opción es lograr que el sistema de postratamiento alcance su temperatura de activación lo más pronto posible. En este trabajo se aborda este objetivo mediante dos soluciones. Por un lado, se ha explorado la posibilidad de elevar la temperatura de los gases en el escape mediante un sistema de distribución variable. Con este método se pueden reducir las emisiones de CO y HC en torno a un 40-50 % y las emisiones de NOx hasta un 15 % durante la primera fase del ciclo WLTC, a costa de una penalización en el consumo de combustible. Por otro lado, también se ha estudiado la posibilidad de aislar térmicamente el sistema de escape. En este caso, es posible reducir las emisiones de CO y HC en torno a un 30 % sin mejorar las de NOx. / [CA] Les noves regulacions en matèria d'emissions d'efecte d'hivernacle i qualitat de l'aire han conduït la evolució tecnològica dels motors de combustió interna durant els darrers anys. Les millores en el procés de la combustió, la sobrealimentació, la gestió tèrmica, els sistemes de postractament i tècniques com la recirculació de gasos d'escapament, han permès que els motors de combustió interna d'avui dia siguen cada vegada més nets. L'adopció a Europa del nou cicle d'homologació WLTP, que considera un cicle de conducció més realista que el seu predecessor el NEDC, així com la necessitat d'avaluar les emissions de gasos contaminants en diferents escenaris de temperatura ambient i humitat, suposen un repte per als fabricants a l'hora de dissenyar i optimitzar els seus motors. En aquest context, el modelatge unidimensional del motor ofereix la possibilitat de desenvolupar i provar diferents solucions amb la suficient precisió, al mateix temps que agilitza el procés de disseny del motor i reduïx els costos derivats d'aquest. L'objectiu d'aquesta tesi és el de desenvolupar un model complete de motor virtual que permeta simular condicions transitòries de règim de gir i grau de càrrega, així com diferents condicions ambientals de pressió i temperatura. Amb aquest model de motor es pretén predir les principals variables termo-fluidodinàmiques en diferents punts del motor i les emissions contaminants alliberades en l'escapament. Per altra banda, l'arrancada en fred i el funcionament a baixes temperatures están associats a un major consum, majors emissions d'hidrocarburs (HC) i monòxid de carboni (CO), així com majors emissions d'òxids de nitrògen (NOx) degudes a la desactivació dels sistemes de recirculació de gasos d'escapament. Per a pal·liar aquestos efectes indesitjats, una opció és aconseguir que el sistema de postractament arribe a la seua temperatura d'activació el més prompte possible. En aquest treball, aquest objectiu s'aborda mitjançant dues solucions. Per una banda, s'ha investigat la possibilitat d'augmentar la temperatura dels gasos en l'escapament per mitjà d'un sistema de distribució variable. Amb aquest mètode s'ha aconseguit reduïr les emissions de CO i HC al voltant d'un 40-50 % i les emissions de NOx fins a un 15 % durant la primera fase del cicle WLTC, acosta d'una penalització en el consum de combustible. Per altra banda, també s'ha estudiat la possibilitat d'aïllar tèrmicament el sistema d'escapament. En aquest cas, és possible reduir les emissions de CO i HC vora un 30 % sense millorar les de NOx . / [EN] The new regulations regarding greenhouse emissions and air quality have led the technological progress of the internal combustion engines during the recent years. Improvements in the combustion process, turbocharging, thermal management, after-treatment systems and techniques such as the exhaust gases recirculation, have resulted in cleaner internal combustion engines. The adoption of the new type approval test in Europe, so-called WLTP, which represents a more realistic driving cycle than its forerunner the NEDC, as well as the need to evaluate pollutant emissions at different conditions of ambient temperature and altitude, represent a challenge for manufacturers when it comes to design and optimise their engines. In this context, one-dimensional engine models offer the possibility to develop and test different solutions with enough accuracy, while hastening the engine design process and reducing its costs. The main objective of this thesis is to develop a complete virtual engine model able to simulate transient conditions of engine speed and load, as well as different ambient conditions of pressure and temperature. The engine model is used to predict the main thermo-and fluid dynamic variables at different engine locations and the tailpipe pollutant emissions. Furthermore, engine cold start and its operation at low temperature is associated to a greater fuel consumption, hydrocarbon (HC) and carbon monoxide (CO) emissions; as well as more nitrogen oxide (NOx) emissions due to the deactivation of the exhaust gases recirculation systems. A solution to mitigate these negative effects is to heat up the after-treatment system so as to achieve its activation temperature as soon as possible. In the work presented, this goal is addressed through two different standpoints. On the one hand, variable valve timing systems have been studied as a way to increase the exhaust gases temperature. With this option it is possible to reduce CO and HC emissions by 40-50 % and NOx emissions by 15 % during the first stage of the WLTC cycle, at the expense of a penalty in the fuel consumption. On the other hand, the thermal insulation of the exhaust system has also been studied with the same objective. In this case, it is possible to reduce CO and HC emissions by 30 %, while not improving NOx ones. / The author wishes to acknowledge the financial support received through the FPI S2 2018 1048 grant of Programa de Apoyo para la Investigación y Desarrollo (PAID) of Universitat Politècnica de València. / Auñón García, Á. (2021). Development and validation of a virtual engine model for simulating standard testing cycles [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/168906

In support of a short dissertation entitled - "A critical review of the source and residence principles of taxation of income : A place for both principles in the South African tax system?" Qbjeetives To review and critically examine the application of the source and reside.nce principles regarding the taxption of income in South Africa, and to reveal the extent of the existence and application of a hybrid tax system in respect of the source and residence principles. To examine the legal principles and policy considerations arising from the existence of a hybrid tax system, inter alia, in the context of the Fifth Interim Report of the Katz Commission and consequent legislative developments. with a view to recommending. where appropriate, tax reform. Methodology iDd AQProach A review of relevant authority,liter@ture, principles and legislation. Conclusion To draw conclusions and recommendations regarding the merits of adopting a hybrid system in South Africa and, where appropriate, recommend legislative reforms particularly with regard to business income. / Mercantile Law / LL.M. (Mercantile Law)

In support of a short dissertation entitled - "A critical review of the source and residence principles of taxation of income : A place for both principles in the South African tax system?" Qbjeetives To review and critically examine the application of the source and reside.nce principles regarding the taxption of income in South Africa, and to reveal the extent of the existence and application of a hybrid tax system in respect of the source and residence principles. To examine the legal principles and policy considerations arising from the existence of a hybrid tax system, inter alia, in the context of the Fifth Interim Report of the Katz Commission and consequent legislative developments. with a view to recommending. where appropriate, tax reform. Methodology iDd AQProach A review of relevant authority,liter@ture, principles and legislation. Conclusion To draw conclusions and recommendations regarding the merits of adopting a hybrid system in South Africa and, where appropriate, recommend legislative reforms particularly with regard to business income. / Mercantile Law / LL.M. (Mercantile Law)

Within the worldwide business community, many analysis tools and techniques have evolved to assist in the evaluation and encouragement of financial health and fiscal viability. However, in the educational community, such analysis is uncommon. It has long been argued that educational institutions bear little resemblance to, and should not be treated like, businesses. This research identifies an educational environment where educational institutions are, indeed, businesses, and may greatly benefit from the use of business analyses. The worldwide effort of Education for All (EFA) has focused on primary education, particularly in less developed countries (LDCs). In Sub-Saharan Africa, Uganda increased its primary school enrollments from 2.7 million in 1996 to 7.6 million in 2003. This rapid primary school expansion substantially increased the demand for secondary education. Limited government funding for secondary schools created an educational bottleneck. In response to this demand, laws were passed to allow the establishment of private secondary schools, operated and taxed as businesses. Revenue reports, filed by individual private schools with the Uganda Revenue Authority, formed the database for the financial analysis portion of this research. These reports, required of all profitable businesses in Uganda, are similar to audited corporate financial statements. Survey data and national examination (UNEB) scores were also utilized. This research explored standard business financial analysis tools, including financial statement ratio analysis, and evaluated the applicability of each to this LDC educational environment. A model for financial assessment was developed and industry averages were calculated for private secondary schools in the Mukono District of Uganda. Industry averages can be used by individual schools as benchmarks in assessing their own financial health. Substantial deviations from the norms signal areas of potential concern. Schools may take appropriate corrective action, leading to sustainable fiscal viability. An example of such analysis is provided. Finally, school financial health, defined by eight financial measures, was compared with quality of education, defined by UNEB scores. Worldwide, much attention is given to education and its role in development. This research, with its model for financial assessment of private LDC schools, offers a new and pragmatic perspective.

This Master Thesis is the research done in the country of Rwanda. The project leads to study the climate of this country in order to establish whether this climate could be used to produce energy from air and to implement the first wind turbine for serving the nation.   After an introduction about the historical background of wind power, the thesis work deals with assessment of wind energy potential of Rwanda in focusing of the most suitable place for wind power plants. The best location with annual mean wind speed, the rate of use of turbine with hub height for an annual production per year, the mean wind speeds for 6 sites of Rwanda based on ECMWF for climatic data for one year at relief of altitude of 100m and coordinates are reported too.   The result of energy produced and calculations were done based on power hitting wind turbine generator in order to calculate Kinetic energy and power available at the best location to the measurement over the period of 12 months, that could be hoped for long term.   With help of logarithmic law, where wind speed usually increases with increasing in elevation and the desired wind speeds at all 6 sites were used. The annual energy production was taken into account at the best site with desired wind speed at the initial cost of turbine as well as the cost of energy (COE).However, with comparison of the tariff of EWSA, the price of Wind designed in this Research per kWh is cheaper and suitable for people of Rwanda. / <p><em>Rwanda has considerable opportunities development energy from hydro sources, methane gas, solar and peat deposits. Most of these energy sources have not been fully exploited, such as solar, wind and geothermal. As such wood is still being the major source of energy for 94 per cent of the population and imported petroleum products consume more than 40 per cent of foreign exchange. Energy is a key component of the Rwandan economy. It is thus recognized that the current inadequate and expensive energy supply constitutes a limiting factor to sustainable development. Rwanda’s Vision 2020 emphasizes the need for economic growth, private investment and economic transformation supported by a reliable and affordable energy supply as a key factor for the development process. To achieve this transformation, the country will need to increase energy production and diversify into alternative energy sources. Rwandan nations don’t have small-scale solar, wind, and geothermal devices in operation providing energy to urban and rural areas. These types of energy production are especially useful in remote locations because of the excessive cost of transporting electricity from large-scale power plants. The application of renewable energy technology has the potential to alleviate many of the problems that face the people of Rwanda every day, especially if done so in a sustainable manner that prioritizes human rights.</em></p>