The development of a polyimide and metals multi-user surface micro-machining process for Micro-electro-mechanical Systems (MEMS) is presented. The process was designed to be as general as possible, and designed to be capable to fabricate different designs on a single silicon wafer. The process was not optimized with the purpose of fabricating any one specific device but can be tweaked to satisfy individual needs depending on the application. The fabrication process uses Polyimide as the structural material and three separated metallization layers that can be interconnected depending on the desired application. The technology allows the development of out-of-plane compliant mechanisms, which can be combined with six variations of different physical principles for actuation and sensing on a single processed silicon wafer. These variations are: electrostatic motion, thermal bimorph actuation, capacitive sensing, magnetic sensing, thermocouple-based sensing and radio frequency transmission and reception.

Master’s thesis deals with developing of multimedia application that allow play and receive multimedia files as audio and video. In thesis introduction, there is theory overview about programming language J2ME, its parts and divisions in couple of chapters. The applications developing begin by choosing focus groups and also group of devices that agree with present trends about mobile devices. The next part undertakes selecting development tool NetBeans IDE based on requirements for multimedia develop and also undertakes selecting software development kit Nokia SDK and its short definition. Afterwards, the application and its basic classes and methods are briefly characterized. The chapters of classes and methods are divided according algorithm level, following development description dividing aspect. Program functions are enriched with flow diagrams completing written text, which have marked important points of program. The main chapters describing algorithm parts begin with define audio and video play. The other pages include description of network connection a data transfers. In every part the programmer part, algorithm is analyzed first and than general options and functionality of this area. In file play part, it is selection of file and proceeding to launch playing with function control possibility. In case of network connection, it is access to network and data handling, eventually communication with each other in client - server hierarchy and consequential multimedia content playing. In the end of development part, reader is cognizant of application fault handling that is inherently part of every application working with I/O data. Next chapter is devoted to future development a design resulting to present process. In the thesis it can be found also application description from user’s point of view, user manual a solving incurred problem situations. In the instructions, there are contained screenshots of described parts of program. Reached results and reviews are summarized on the end of the thesis.

This diploma thesis deals with developing multimedia applications on Java Micro Edition platform. The aim of this work is to design and implement the application which could establish a call between two users. The first part of the work describes J2ME platform, its two configurations and profiles. Next part is focused on Session Initiation Protocol and Real-time Transport Protocol. The application design consists of choosing the suitable virtual machine JVM, SIP and RTP libraries. The main part of this work describes application structure, graphic user interface and installation packages creating. It also shows a way of customizing the media stack - Java Media Framework, version Cross Platform.

Magister Artium (Development Studies) - MA(DVS) / This thesis is both a qualitative and quantitative study, investigating the sustainability of Credit Management Services Limited (CMS) within the broader context of the Zambian micro finance industry. Micro finance is regarded as one of the tools for poverty reduction. As such, making microfinance available to many poor people is the purpose of microJinance. Over the years it has become clear that microfinance institutions have to operate efficiently and be self-sustai nable in order to continue assisting the poor. However. in spite of the support and encouragement given for sustainability, evidence shows that there are few sustainable microfinanee institutions in the world. The various factors impacting upon sustainability therefore, need to be examined and means of enhancing sustainabi Ii ty mapped out. The study brought to the fo re the main viewpoints regarding sustainability and how they have been inl1uenced by experiences of MFls around the world. The framework for discussion and analysis of operational sustainability, financial sustainability and operational e ffi ciency is also set out. The study discusses the Zambian microfinance industry and shows how and why the industry has emerged and grown in the past decade. Some constraints are identified that need to be dealt with in order to enhance sustainability of the industry. The study of CMS reveals that the institution is not yet fi nancially sustainable, but that its effi ciency levels are steadily increasing as it has put in place mechanisms to recover costs, charge economic rates of interest and increase and maintain its client outreach. Indicators are that it is moving in the right direction with its cost recovery. increasing client outreach and utilization of loans for on-lending as opposed to subsidies. This study therefore draws on the general experiences of the Credit management Services in order to draw lessons for the Zambian industry. The study will argue the case that though sustainability is difiicult to achieve, there arc positive indicators in the Zambian industry that this is possible and that CMS could be considered as an example. This claim is verified against the experi ence on the ground of Credit Management Services. The study concludes that building a sustainable microfinance industry anywhere is not the easiest task. Sustainabi lity is possible but requires a lot of investment in capacity bui lding and del iberate steps for cost effi ciency, appropriate pricing poli cies and an increased client outreach. The Zambian situation characterised by even a younger industry. will require not only a concerted effort in capacity building, but much more, the need to counter constra ints in the external environment of Mrls. Recommendations lo stake holders inc lude the need to utilise cheaper local human resources and invest in strengthening local institutions owned by local communities, to enhance the sustainability or micro finance initiatives.

Ingeniero Civil Eléctrico / Los últimos años el cambio climático, los avances en tecnología y la creciente explotación de las fuentes renovables de energía han motivado investigación y desarrollo en torno a la incorporación de estas fuentes a los sistemas eléctricos. Dicha incorporación se ha dado a gran escala en el sector de generación, pero también ha tomado fuerza el último tiempo el desarrollo de micro y nano redes. Estas redes más pequeñas que cuentan con generación mediante fuentes renovables pueden operar conectadas al sistema de distribución o también en modo isla, es decir, de forma autónoma. Por otro lado, el desarrollo de la urbanización ha ido creciendo. En este ámbito, para poder llevar energía eléctrica a nuevos lugares se necesitan expansiones en las redes de distribución (y transmisión en caso de ser necesario), las cuales requieren grandes inversiones. Una alternativa a esto es la generación distribuida o generación en los lugares de consumo en MR o NR. En este trabajo se propone una metodología para diseñar MR y NR, que consta de un modelo matemático para optimizar su tamaño. La metodología se prueba para distintos escenarios geográficos y de consumo. Los resultados, comparados con una herramienta especializada (HOMER), muestran que el modelo funciona correctamente y entrega un resultado cercano al óptimo. Así, se tiene un modelo simple, con pocas variables a considerar y que reduce el tiempo de cálculo considerablemente. Luego, se propone una estrategia de control para operar la NR y demostrar que el dimensionamiento entrega una solución que es estable. El esquema de control primario está basado en control Droop, con el que se controla tensión y frecuencia de la red. Los casos de estudio muestran que la NR se comporta de buena manera ante variaciones en el consumo y generación. Con esto se tiene una metodología de diseño simple, rápida y que entrega buenos resultados para dimensionar NR, especialmente de bajo consumo. Se pueden dimensionar los módulos de forma correcta gracias a que, al tener menos unidades de generación y almacenamiento, el error que hay en el cálculo de su desempeño es menor. Dado esto, simplificar ecuaciones sacrificando detalle, permite tener un resultado correcto (similar al de los cálculos más detallados hechos por herramientas especializadas) en menor tiempo.

La Macroglobulinémie de Waldenström (MW) est un type de lymphome à cellules B de faible grade dont la pathogénèse est caractérisée par différents stades de progression. La MW asymptomatique n’occasionne pas de symptômes sévères chez les patients qui en sont atteints et nécessite une observation régulière mais pas de traitement. Elle peut évoluer en une forme symptomatique aux effets nocifs qui requiert un traitement par chimiothérapie. Le développement de la MW est généralement précédé par l’apparition d’un syndrome précurseur appelé Gammapathie Monoclonale de Signification Indéterminée à Immunoglobuline M (GMSI à IgM). Bien que les conséquences cliniques des formes asymptomatique et symptomatique de la maladie soient dramatiquement différentes pour les patients, au niveau cellulaire peu de différences permettant d’expliquer ce contraste ont été identifiées. Les mécanismes moléculaires de progression de la maladie restent donc majoritairement à élucider.Les exosomes sont des vésicules d’une taille de 40 à 100 nanomètres sécrétées par les cellules. Ils assurent le transport de protéines, de lipides et de molécules d’ARN ou d’ADN entre les cellules de l'organisme et constituent ainsi un moyen de communication intercellulaire. Ces propriétés permettent aux exosomes de conditionner le microenvironnement tumoral afin de le rendre favorable à la survie et la dissémination des cellules tumorales.Le but de cette étude est d’analyser le contenu des exosomes circulants chez les patients atteints de MW afin d’identifier des microARNs exprimés différentiellement en fonction du stade de progression de la maladie.Pour cela, les exosomes présents dans le sang circulant de patients à différents stades de la maladie (GMSI à IgM, MW asymptomatique et MW symptomatique) et d’individus sains ont été isolés. Le contenu en microARNs de ces exosomes a été analysé dans un premier temps par qRT-PCR puis par une technique utilisant la cytométrie de flux. Ces analyses ont permis d’identifier un groupe de microARNs dont l’expression corrèle directement ou inversement avec la progression de la maladie.En parallèle, l’ADN contenu dans les exosomes de certains de ces échantillons a également été extrait afin de détecter la fraction de variants mutés pour MYD88, un gène muté chez environ 90% des patients atteints de MW. Cette analyse permettra d’identifier une potentielle corrélation entre la progression de la maladie, la fraction de variants mutés de MYD88 et l’expression de certains microARNs dans les exosomes circulants. / Waldenström Macroglobulinemia (WM) is a low- grade B-cell lymphoma with a heterogenous clinical presentation. In patients with the asymptomatic form of the disease, no severe symptoms are observed and only monitoring is recommended. However, it can evolve into symptomatic WM in which case the patients will require treatment with chemotherapy .In many patients, the diagnosis is preceded with an asymptomatic precursor state of IgM monoclonal gammopathy of undetermined significance (MGUS). To date, the molecular mechanisms involved in the progression from asymptomatic WM to symptomatic WM remain to be elucidated.Exosomes are small vesicles secreted by cells with a size ranging from 40 to 100 nanometers that mediate the transfer of nucleic acids, proteins and lipids between distant cells in the organism. Exosomes enable communication between cells and the conditioning of distant tissues throughout the body.The goal of this study is to analyze the microRNA content of circulating exosomes in patients at different stages of WM progression to identify microRNAs which expression correlates with disease progression.Exosomes were isolated from the peripheral blood of healthy individuals and patients with WM at different stages (IgM MGUS, asymptomatic WM and symptomatic WM). The microRNA content of these exosomes was analyzed first by qRT-PCR and then by a technique involving flow cytometry. These analyses revealed a group of microRNAs which expression correlated directly or inversely with disease progression.In parallel, the DNA content of some of the exosomes was extracted in order to detect the fraction of mutated MYD88, a gene mutated in approximately 90% of patients with WM. This could potentially identify a correlation between disease progression, the fraction of mutated MYD88 and the expression of specific microRNAs in circulating exosomes.

This study dealt with the issue of sustainability of ICT4D initiatives being a problem with few success stories (Heeks, 2002, Toyama, 2010). Many of these initiatives were planned and executed in a top-down fashion by large funders and governments, and these failures have stimulated the search for new strategies to achieve long-term sustainability. One possible approach is to consider the different levels of systems that are involved. The reasons for failure lie inside the scope of a project, within the community itself, and outside the community in the larger socio-economic system which includes the economy. A systems approach with respect to the analysis of the sustainability (or lack thereof) of development initiatives was therefore adopted. The Choice Framework of Dorothea Kleine (2010) was used since it is a systemic approach, developed in the study of ICT4D initiatives, that embraces the complexity of engaging with development paradigms, societal structures and personal agency. The research was done on a large South African government initiative, the Broadband-for-All (BB4All), community-based wireless mesh network project which aimed to provide a cost-effective way of enabling reliable broadband connectivity in rural areas. The project had two key aspects, the provision of a large-scale demonstrator of a wireless mesh network (WMN) as a broadband solution and the establishment of a Village Operator (VO) model to support access to and increase the use of the technology. The teachers and learners in more than 170 schools were the primary customers. Young people from local communities were trained as VOs to become local entrepreneurs (micro-enterprises) responsible for operating and supporting the BB4All service in their assigned cluster of schools and respective communities. The research focus was the sustainability of the VOs. The Choice Framework was used to provide a context for the research regarding the role played by social resources (social capital) in contributing to the sustainability of the VO micro-enterprises. In-depth interviews were held with all but one of the 15 VOs in order to develop an understanding of their social capital and the influence thereof on them as entrepreneurs. The importance and usefulness of social capital in supporting sustainability at VO and initiative level was analysed. Three major themes emerged that were analysed in detail, namely, the role of social capital, community service and social entrepreneurship, as well as the development of networks of innovation. At a theoretical level, the research reflected on implications of the findings for the role of social capital in the Choice Framework. At a practical level, considerations for using a social capital perspective in order to improve the conceptualisation, design, implementation and transfer of ICT4D initiatives for sustainability were developed. / Thesis (PhD)--University of Pretoria, 2016. / Informatics / PhD / Unrestricted

No description available.

Although the suspended droplet evaporation and combustion have been studied for decades, fundamental research pertaining to the stochastic phenomena of complex multicomponent mixtures is extremely rare. In this work, an experimental suspended droplet study of Arabian light oil was held to study the frequency of puffing and micro-explosion phenomena during the evaporation/pyrolysis process. The experiments were conducted at three different evaporation temperatures (350 C, 440 C, and 570 C), chosen in accordance with the TGA profle obtained. The suspended droplet experiments were conducted on a furnace with optical access and a gas controlled-preheating system. The droplet size was optically registered at 500 fps by a LaVision Imager Pro HS high-speed camera coupled with a magnification lens Nikon AF-S Micro Nikkor 105 mm. Furthermore, a computer-vision data postprocessing program was developed to identify contours and measure the size of the objects in the frame in order to register the temporal evolution of the droplet size. Additionally, a new approach for characterizing the droplet vaporization of complex multi-component fuels is proposed. This method allowed us to study the continuum (ideal evaporation) and stochastic processes separately, by following the profile of the average normalized square diameter ((D=D0)2) and quantifying the breakup intensity (β) of each stochastic event. Based on the behavior of (D=D0)2, two consecutive stages were identified at every temperature investigated, the swelling and the regression stage. At 350 ◦C and 440 ◦C, the evaporation was finally controlled purely by the diffusion evaporation, whereas at 570 ◦C a pure diffusion stage was not spotted. Instead, a second swelling was registered, where an amorphous carbonaceous structure was formed. Due to the pyrolysis of the heavy hydrocarbons dominated the process. The stochastic events involved during the evaporation were successfully identified and classified in breakup modes depending on their β. Additionally, the effect of the temperature on the breakup events was assessed. Showing that the number of breakup events increased exponentially with temperature.

MCom (Business Management) / Department of Business Management / The spaza-shop sector is an integral part of the Small, Medium and Micro Enterprises (SMMEs) in the South African economy. The industry is made up of more than 100 000 enterprises with a collective annual turnover of R7 billion. Spaza shops also contribute about 4% (about 100 000 jobs) of employment in the informal sector. Spaza shops usually have a short lifespan and rarely grow; the failure rate of spaza shops, including those owned by immigrants is very high in South Africa. It is estimated that the failure rate of small businesses (including spaza shops) in South Africa is between 70% and 80%. It is also noted that about 50% of small businesses fail within the first five years of commencement of business, irrespective of the country. Despite severe competitive pressures faced by SMMEs, immigrants (especially Somalis and Ethiopians) have established a strong foothold in the spaza-shop sector. The main objective of the study was to investigate the success factors of immigrant-owned spaza shops in Thulamela Local Municipality. To address the research question, which focuses on the lived experiences and perceptions of participants, the interpretivist paradigm was used. A qualitative approach was adopted with a sample of 25 participants; purposive sampling was used to select participants with the required characteristics. Structured interview questions administered through face-to-face interviews were used to collect data and content analysis was used to analyse data. The data collected revealed that there are a plethora of success factors that are enhancing the continuance and sustenance of immigrant spaza shops in Thulamela Local Municipality. Of these, the most frequently given ones include - human capital, networks, culture, superior customer service, long operating hours and business location. The researcher recommended that immigrant spaza-shop entrepreneurs should establish a mentorship program that will assist in training other local spaza-owners to successfully manage their enterprises, in a bid to create harmony within the sector and to promote job creation. / NRF