The Swedish mining company LKAB is using limestone as additives for the production of its iron ore pellets. The company is considering five new proposals of limestones since the Nordkalk Company is soon no longer able to provide limestone from the Storugns quarry which is the one that is used today. The first purpose in this study was to characterize and compare these five new limestones in respect to their texture and their disintegration during the transport from the quarry to the final destination in Malmberget, considering the Storugns limestone as a reference material. The second aim was to focus on finding any link between texture and disintegration properties of the limestones. Another intention is that the methodology which is used in this study will help the company to consider new proposals of limestones in the future. Six limestones from the Orsa, Storugns, Stucks, Vasalemma, Verdal and Võhmuta quarries were analyzed by an optical microscopy analysis of the textures. Two types of physical tests were also included in the study: a tumbler test and a breakage test. Six different textures were identified by a qualitative thin section analysis which shows similarities between the limestones from different origins but also a high variability of texture within a same quarry. A more quantitative optical microscopy analysis led to the assumption of both the degree of lithification and the amount of initial micro-cracks for each sample. According to the physical test results, the limestones disintegrate as follows, from the less to the more disintegrated: Stucks (7,6%), Storugns (9,4%), Verdal (10,3%), Võhmuta (11,1%), Vasalemma (11,8%) and Orsa (17,6%). There is no evident textural parameter which is controlling directly the disintegration of limestone. However the samples with a rather high lithification and a rather low fracturing disintegrate less than samples with a rather low lithification and a rather high fracturing. It is assumed that the combination of degree of lithification together with the amount of initial micro-cracks is somehow controlling the disintegration of limestone. / Validerat; 20101217 (root)

Philosophiae Doctor - PhD / The researcher attempted to assess the effectiveness of Bank of Agriculture (BOA) microloan scheme on job creation among micro and small enterprises. This is in view of the unprecedented rise in the unemployment rate in Nigeria and the widely perceived belief that among other policies, harnessing the financial capacity of micro, small and medium enterprises (MSMEs) may possibly dictate the pace of the country’s achievement of job creation. Despite a wide array of studies on MSME growth, only a handful of rigorous studies are available to provide evidence of the effect of finance on labour market outcomes in the sector, as well as on the use of more relevant assessment techniques on the performance of public policies and interventions related to MSME financing. Through the use of mixed methods including questionnaire administration, key informant interviews, focused group discussions and desk research, this research undertook a theory of change-based assessment of Bank of Agriculture microfinance scheme, to assess the extent to which the scheme is effective in contributing to the achievement of the MSME Policy’s fundamental objective of job creation. Descriptive statistics using frequency tables and graphs as well as OECD COTE (Coherence, Objectives, Targets and Evaluation) Framework for policy formulation were applied as methods of analysis. The findings show a fundamental flaw in relation to the lack of strategic alignment of the Bank of Agriculture (BOA) operations with the MSME Policy. The Bank is seen to be operating in a silo as the strategic direction the MSME tilt does not seem to derive from the overall MSME Policy. BOA is also not seen to be positioned to engage the practice of performance measurement and reporting generally and in particular of the fundamental objective of job creation, as stipulated in the MSME Financing Policy of government. It was also revealed that a majority of enterprises that took BOA microloans loans were not able to create jobs as many of them were operating as “survivalists”. Although the BOA microloan scheme is potentially capable of supporting targeted growth-oriented microenterprises in specific trades to create jobs, given the attractive concessional terms, the Bank is not achieving this objective in its present state and form neither is it seen to be positioned to do so due to several supply and demand side factors. An ongoing reform process in the Bank during this research period may be able to address part of this concern if more strategic steps are taken to surmount the constraints. Furthermore, BOA does not have a functional performance measurement framework and monitoring and evaluation system that can be used as the basis for measuring goal attainment such as the goal of job creation, especially in relation to the outcomes of the provision of financial services to the MSME sector. For BOA to be successful and truly developmental in focus especially in relation to its contribution to the strategic objective of job creation, the study therefore recommended the key thrust of a new framework for addressing the current unemployment situation to include an effective alignment of macro, meso (sectoral) and micro policies. At the (micro) institutional level, it is recommended that BOA should: • improve its governance and management system as well as the integration of development impact considerations and measurement; • create innovative financing products for growth-oriented microenterprises especially through cluster financing and cluster-based development; • increase wholesale lending through the provision of on-lending products to performing microfinance institutions (MFIs); • engage the services of BDS organisations to source for credible clients and build clients’ entrepreneurial capacity including assisting them to access markets. In line with the need to integrate development impact considerations and measurement into its entire operations, the researcher designed a monitoring and evaluation framework that can enhance the tracking of the attainment of job creation policy goal in BOA microloan scheme. In this vein, the institution is to adopt formal “lessons learnt” mechanisms to integrate evaluation findings into future activities and “put development back into development banking” (Smallridge, 2017). At the meso level in the study context, horizontal cooperation is recommended where all relevant institutions are aligned and the impact of various policy measures on entrepreneurship and job creation are taken into account. Lastly, an employment – sensitive macro-economic framework must pursue: the relaxation of monetary and credit conditions that are supportive of employment creation in the economy; fiscal prudence in the context of exploiting fiscal space to accommodate investments with high employment potentials; use of legislative mechanisms for ensuring full and effective implementation of annual budgets, program and projects at all levels and development and effective use of computerised Labour Market Information System (LMIS) for Nigeria.

Ingeniero Civil Eléctrico / Los sistemas de generación distribuida basados en fuentes renovables han experimentado un fuerte desarrollo a nivel mundial, con Alemania, Dinamarca, Japón y Estados Unidos como líderes en este campo. La sincronización de este tipo de fuentes a la red de suministro eléctrico es uno de los aspectos más importantes. La detección de la componente de secuencia positiva de la tensión a frecuencia fundamental es esencial para el control de la generación distribuida y de sistemas de almacenamiento. Considerando el contexto descrito, el objetivo general del presente trabajo es la elección de un algoritmo para la estimación de ángulo de fase en función del desempeño demostrado frente a distintas perturbaciones típicas de la red de distribución para su implementación en la Central Micro Hidráulica Plug & Play, correspondiente a un proyecto de desarrollo del Centro de Energía de la Universidad de Chile. Los métodos estudiados se basan en la técnica Phase Locked-Loop (PLL). La técnica PLL se puede definir como un método que permite la obtención de una señal de salida de igual frecuencia y fase a partir de una señal de entrada. El criterio de selección supone la simulación de distintos tipos de perturbaciones tales como distorsión armónica e interarmónica, alzas y caídas de tensión y saltos de frecuencia, entre otros. El funcionamiento de los algoritmos se prueba a nivel de simulación y a nivel experimental en la Central Micro Hidráulica Plug & Play con el fin de verificar su desempeño en condiciones reales de operación. Con el propósito de mejorar la respuesta dinámica de los algoritmos, se implementa, a nivel de simulación, una mejora del centro de frecuencia del esquema básico de PLL. De este modo se obtienen métodos que combinan un buen seguimiento de ángulo de fase y una buena velocidad de respuesta ante variaciones de la frecuencia de la red. Del trabajo realizado se desprende que las perturbaciones que combinan saltos de fase y desbalances de la magnitud de la tensión son más severas que aquellas que implican distorsión de la forma de onda o únicamente desbalances, los cuales se consideran menos graves; la diferencia entre el error de estimación en uno u otro caso puede ascender sobre los 5°. Los métodos de detección de ángulo de fase presentan un compromiso entre la dinámica y la precisión de seguimiento del ángulo de fase; dándose el caso de un error de estimación de 180° frente a saltos de frecuencia. Se concluye que los algoritmos basados en filtros presentan un mejor desempeño que aquellos basados en la componente de secuencia positiva de la tensión de la red de suministro, con diferencias entre sus errores de seguimiento acumulado de hasta 200 veces en el caso de sags de tensión y de hasta 6 veces frente a contenido armónico. El mejor método estudiado se basa en el uso de un observador y obtiene resultados ligeramente mejores que los presentados por los métodos basados en filtros. El conocimiento previo de las características del sistema es vital para la correcta sintonización de los métodos, pues determina el desempeño de los algoritmos. Se concluye que los métodos basados en PLL son una herramienta eficaz para la detección del ángulo de fase ante perturbaciones típicas de la red eléctrica de distribución. Adicionalmente, con el fin destacar más aún su utilidad, se simula el uso del PLL para la detección de operación en isla. Como trabajo futuro, entre otras cosas, se propone: la implementación experimental de centro de frecuencia variable y del mecanismo de detección de aislamiento, y la evaluación de los métodos frente a perturbaciones combinadas.

Doctor en Ingeniería Eléctrica / Las micro-redes están convirtiéndose en un componente clave de la red eléctrica futura, las cuales representan la combinación de tecnologías de información y comunicación, junto con fuentes de energía y cargas, en un sistema unificado y activo. Los beneficios de las micro-redes han promovido esfuerzos globales para expandir su penetración en los sistemas eléctricos. Sin embargo, todavía hay algunos desafíos relacionados con su diseño, control y operación. Uno de los problemas más importantes por resolver es el desarrollo de nuevos sistemas de protección, considerando que los esquemas convencionales, diseñados para flujos de potencia radiales, y con altas magnitudes de corrientes de falla, no funcionarán correctamente en este nuevo entorno. El uso de un adecuado sistema de protección es esencial para el funcionamiento seguro y confiable de la micro-red. La adopción de un sistema de protección adquiere mayor relevancia dada la presencia de fuentes de energía altamente variables, con cambios continuos en las condiciones de operación y topológicos. En este sentido, los enfoques de protección adaptativos están siendo considerados como una solución viable, ya que su función protectora cambia en función del comportamiento de la micro-red, satisfaciendo los requisitos de confiabilidad, selectividad, rapidez y sensibilidad. En esta tesis, se presenta un novedoso sistema de protección adaptativo para micro-redes. El esquema de protección se basa en funciones protectoras que incluyen diferentes elementos, operando de manera coordinada. Entre las principales contribuciones de la tesis se encuentra la conceptualización del problema de las fallas y anomalías en las micro-redes. Además, se destaca la forma en que se adaptan los parámetros de los dispositivos de protección, utilizando un enfoque de optimización robusta, resolviendo un conjunto finito de escenarios de falla. Los escenarios se generan en función de las predicciones sobre la energía disponible y demanda. Para cada paso de decisión, un problema de optimización robusta se resuelve en línea, basado en el pronóstico con una banda de confianza para representar la incertidumbre. Asimismo, el sistema de protección realiza un diagnóstico de las plantas fotovoltaicas, para detectar fallas y definir sus condiciones de operación. El sistema de protección fue probado y comparado utilizando datos reales de una micro-red existente en Chile. Los resultados obtenidos muestran que el dispositivo de protección propuesto fue capaz de despejar las fallas. Por ejemplo, en la configuración radial, la metodología propuesta eliminó el 100% de las fallas; mientras que una metodología alternativa lo hizo en el 92%. En la configuración de malla, la metodología propuesta despejó el 96% de las fallas; mientras que la alternativa lo hizo en un 75%. Asimismo, la metodología de detección de fallas de las plantas fotovoltaicas fue sensible a los cambios en las condiciones de operación. El modelo de celda fotovoltaica obtuvo un coeficiente de determinación de 0,992 para el voltaje, y 0,999 para la potencia, lo que significa que se logró un buen ajuste del modelo. Como trabajo futuro, se deberán abordar sistemáticamente los problemas de confiabilidad relacionados con fallas en el sistema de comunicación. Finalmente, se deberán considerar dentro de la metodología las acciones correctivas realizadas por los sistemas de gestión de carga, con el fin de mejorar el rendimiento del sistema de protección. / Este trabajo de tesis ha sido financiado por: Comisión Nacional de Investigación Científica y Tecnológica de Chile Universidad de Costa Rica

The practice of using X-Ray fluorescence analysis as a method in ar-chaeological, forensic and osteological studies have resulted in a vast amount of data. It is time and cost efficient, and the method of µXRF element analysis has been of great use to archaeologists, forensic an-thropologists and osteologists to understand dietary customs, techno-logical trade patterns, understanding of diagenesis, elemental accumu-lation in bone and more. Moreover, the method has been crucial due to its non-destructive nature since bones and ancient artifacts are fragile and thus a nonde-structive method is preferable. This essay will give the reader an intro-duction to the basics of micro X-Ray fluorescence analysis and will explore the possibilities of trace elements in right (dexter) and left (sinister) thighbones (femur) on a medieval population in Visby Got-land, namely Sankt Hans. The reader will also come to know the fun-damental principles, applications, strengths and weaknesses of mi-croX-Ray fluorescence, as well as its limitations. Keywords: µXRF, non-destructive, data, method, left, right, thigh-bone, elements, analysis.

Thesis (M.M. (Finance & Investment))--University of the Witwatersrand, Faculty of Commerce, Law and Management, Graduate School of Business Administration, 2013. / This research work explores the risks that microfinance institutions (MFIs) face in their operations and the risk management strategies they adopt to mitigate their risks. Microfinance institutions serve some of the world’s most financially challenged population who otherwise would not have access to banking services. Risk management within the context of microfinance banking has gained importance within the last decade due partly to the fact that most MFIs are adopting business/profitability principles in their operations. Also, due to the recent financial crisis, MFI cannot afford to be indifferent to risk management practices in the battle for survival, financial sustainability and self-sufficiency. The data for this study is from both secondary and primary sources; 48 MFIs in Ghana responded to a questionnaire made up of 25 questions. Analysis of the responses obtained was done using Chi-Square test of equal proportions, P-values and other descriptive statistics. The Analysis found that the microfinance institutions surveyed are aware of the types of risk inherent in their line of business and do in varying ways employ some form of risk management strategies to mitigate losses and enhance profitability. Since credit granting stands at the core of the operations of MFIs, the management of risk as a result of the credits extended is crucial for their survival and profitability.

La peau assure la protection de l’organisme contre les agressions extérieures. Pourtant, la peau n’est pas à l’abri des effets inéluctables du vieillissement chronologique. En effet, ce processus a pour conséquence d’altérer la structure des différentes couches cutanées au point d’en affecter leurs caractéristiques fonctionnelles. Ce travail de thèse a pour but de caractériser les modifications moléculaires et structurales de la peau au cours du vieillissement chronologique à l’aide de méthodes non-invasives que sont les spectroscopies optiques vibrationnelles. Ainsi avons-nous pu mettre en évidence des altérations structurales du réseau de collagène dans des échantillons de peaux d’âges différents à l’aide d’une approche basée sur l’imagerie IR-TF (Infrarouge à Transformée de Fourier) en mode polarisé. Par la suite, nous avons démontré l’influence des molécules d’eau sur les changements d’orientation des fibres de collagène avec l’âge en adoptant une méthodologie basée sur la substitution, thermodynamiquement favorable, des molécules d’eau liée au collagène (H2O) par des molécules d’eau deutérée (D2O). Lors d’études réalisées in vivo, nous avons établi des corrélations entre les propriétés physiques (mécanique et statut d’hydratation) et les informations moléculaires du stratum corneum (SC) en traitant les données Raman et biométriques par la méthode des moindres carrés partiels (PLS). En s’appuyant sur la complémentarité des techniques biophysiques employées, ces différentes études ont permis d’illustrer le potentiel des spectroscopies vibrationnelles pour évaluer le vieillissement cutané et en déterminer certaines bases moléculaires. / The skin protects the body against external aggressions. However, the skin is not immune to the inevitable effects of the chronological aging. Indeed, this process leads to several structural alterations of the different cutaneous layers to the point of affecting their functional characteristics. This thesis work aims to assess the molecular and structural changes of the skin during chronological aging by using non-invasive methods such as optical vibrational spectroscopies. To do this, we highlighted the structural modifications of the collagen network in different-aged skin samples by using an approach based on FT-IR imaging (Fourier Transform Infrared) in polarized mode. Subsequently, we demonstrated the influence of water molecules on the changes of collagen fibers with age by adopting a methodology based on the substitution, thermodynamically favorable, of the collagen-bound water molecules (H2O) by deuterated water molecules (D2O). In in vivo studies, we have established correlations between physical and molecular properties of the stratum corneum (SC) by analyzing the Raman and biometric measurements with the Partial Least Squares (PLS) processing. Based on the complementarity of the biophysical techniques employed, these studies permitted to evaluate the impact of the chronological aging on the skin and could open some interesting prospects in both cosmetology and dermatology.

Orientadora: Angela Regina Araujo / Banca: Novaldo Borale / Banca: Geraldo Humberto Silva / Resumo: O fungo endofítico P. stromaticum isolado dos frutos maduros da espécie vegetal E. jambolana foi cultivado em escala ampliada no meio líquido de Malte por 28 dias a 25 oC no modo estático e, no meio sólido de milho tipo canjica por 21 dias a 25 oC no modo estático. Após 28 dias de crescimento no meio líquido, este foi submetido a sucessivas extrações com acetato de etila (AcOEt), que após evaporado forneceu o extrato bruto de Malte AcOEt. O meio sólido, após 21 dias de cultivo, foi extraído com metanol, seguido de filtração e evaporação fornecendo o extrato bruto metanólico. Este foi submetido à partição líquido/líquido com acetato de etila e água, sendo que a fração AcOEt foi evaporada fornecendo o extrato bruto AcOEt. Este foi particionado com acetonitrila e hexano, e após evaporação dos solventes forneceu os extratos acetonitrila (ACN) e hexânico do meio sólido. O extrato ACN do meio sólido passou por novas partições com acetonitrila e hexano, por apresentar ácidos graxos ainda, fornecendo o extrato bruto de milho NP (novas partições). O extrato bruto de Malte AcOEt, foi fracionado em coluna de bancada, sendo coletadas 11 frações (Fr-1 Ps Ma a Fr-11 Ps Ma). Já o extrato bruto de milho NP sofreu partição utilizando-se cartucho de C18, com base em seu cromatograma, resultando em 6 frações (Fr-1 Ps Milho a Fr-6 Ps Milho). Das 6 frações obtidas do extrato de milho NP, escolheu-se trabalhar com a primeira, a qual sofreu partição no CLAE-DAD preparativo, resultando em 8 frações... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The endophytic fungus P. stromaticum isolated from the ripe fruits of the E. jambolana was cultivated in large scale in the malt liquid medium for 28 days at 25 oC in the static mode and in the solid medium of hominy corn for 21 days at 25 oC in static mode. After 28 days of growth in the liquid medium, it was made successive extractions with ethyl acetate (EtOAc). The organic layer was evaporated affording the crude extract of Malt EtOAc. The solid medium, after 21 days of cultivation, was extracted with methanol, followed by filtration and evaporation to give the crude methanolic extract. This was subjected to the liquid/liquid partition with EtOAc and H2O, being this EtOAc fraction evaporated giving the crude EtOAc extract. After that, the extract was partitioned with acetonitrile and hexane, and after the evaporation of the solvents provided the acetonitrile (ACN) and hexane extracts from the solid medium. The ACN extract of the solid medium was partitioned again with ACN and hexane, due the remaining fatty acid, providing the corn crude extract NP (new partitions). The crude extract of Malt EtOAct was fractionated in a chromatographic column, resulting in11 fractions (Fr-1 Ps Ma to Fr-11 Ps Ma). The crude extract of corn NP was fractionated by solid phase extraction in reverse phase (C18), based on its chromatogram, resulting in 6 fractions (Fr-1 Ps Corn to Fr-6 Ps Corn). Among the corn fractions collected, it was chosen the fraction Fr-1 Ps Corn to the chemical studies. This fraction was fractionated by preparative HPLC-DAD resulting in 8 fractions. The crude extract of Malt EtOAc and its fraction and the crude extract of corn NP, were submitted to the chemical evaluation by 1H NMR and biological against the phytopathogenic fungus Cladosporium sphaerospermum (and in the case of corn to C. cladosporioides as well). Besides, anticolinesterasic activity was made, the crude... / Mestre

Micro enterprises have become popularised globally as the favoured option for development and have played a key role in poverty alleviation. The main premise of using micro enterprises has been to build the capacity of the individual to be self- sustaining and to move away from the continued dependency on state welfare. Micro enterprises are also seen as a key tool to allow participation of the disempowered population. In South Africa micro enterprises have been hailed by government as playing a pivotal role in creating employment opportunities for the poor people. The study was conducted to gain a deeper understanding of how beneficiaries view the role played by micro enterprises in reducing poverty. This qualitative research was based on case studies of 12 female participants who were selected using convenience sampling based on their availability and participation in micro enterprise initiatives. An interview schedule was used and the interviews were tape recorded. The major findings that emerged were that beneficiaries perceive micro enterprises as meeting their basic needs like food and rates, to others they were a way of supplementing income. Most participants perceived micro enterprise rather as a hobby than an effective income generating activity. None of the beneficiaries had business skills, equipment or information and capital to grow their business beyond their residential areas. None of the micro enterprises were able to create employment for others. Various factors such as lack of capital, low literacy levels, poor business management skills and non-entrepreneurial mind-set amongst others have resulted in this failure. Beneficiaries of this study perceived the income from their micro enterprises not enough to qualify their micro enterprises as a poverty reduction tool. The main conclusion drawn from the study is that whilst profit generated through participating in micro enterprises meet the beneficiaries’ basic necessities, it is insufficient income to meaningfully reduce poverty.

Esta tese propõe a síntese e o estudo de uma nova técnica de cavidades de borda aplicada a antenas Vivaldi, com o intuito de melhorar suas características de diretividade. Embora as antenas do tipo Vivaldi possuam características diretivas, elas produzem radiações laterais indesejáveis, o que se reflete nos elevados índices de lóbulos laterais devido a correntes superficiais que fluem ao longo das bordas metalizadas nas laterais da antena. Estas correntes são a origem das radiações laterais que vêm sendo mitigadas pela aplicação de cavidades ressonantes, triangulares ou retangulares, que aprisionam tais correntes e, consequentemente, atenuam os lóbulos laterais, sem o incremento do lóbulo principal, uma vez que toda a energia dos lóbulos laterais é apenas confinada nos ressonadores e por isso literalmente perdida. Ao contrário desses esforços, este trabalho propõe cavidades radiantes tanto na forma de abertura exponencial, como na forma do fractais de Koch, que funcionam como radiadores auxiliares (antenas auxiliares), canalizando as correntes de borda e aproveitando-as para aumentar os níveis do lóbulo principal, mitigando os níveis de lóbulo lateral. A síntese desta nova técnica foi implementada em uma antena Vivaldi antipodal com características de baixa diretividade, como qualquer antena Vivaldi, o que foi corrigido e a aplicação da técnica de cavidades radiantes deu origem a duas novas antenas Vivaldis efetivamente diretivas. Os resultados foram obtidos através de simulações do modelo numérico no CST Microwave Studio e confirmados com medidas de laboratório, o que evidenciou a melhora das características de diretividade da antena pela aplicação da nova técnica de cavidades radiantes. / This work presents a new Slot Edge technique applied to Vivaldi antennas to improve their characteristics of directivity, resulting in two new Vivaldi antennas: the Palm Tree Vivaldi antenna and the Koch Vivaldi antenna. This new technique proposes to add lateral radiators which reduce the side lobe level, increasing the gain of the main lobe in an unprecedented way. This technique is called radiating slot edges, and acts as parasitic antennas, surface currents draining edges of the antenna, and using them to increase the gain in the main lobe. The development was done systematically, starting with an extensive literature review, design and simulation in CST, as well as prototyping and measurements of several antenna designs. All this effort proved the functionality of this technique.