Orientador: Ricardo Alan Verdú Ramos / Resumo: A biomassa derivada de microalgas apresenta um grande potencial devido a sua sustentabilidade e alta produtividade, sendo possível extrair lipídios para produção de biodiesel. Entretanto, desafios na cadeia de produção como um todo devem ser resolvidos para que o biodiesel de microalgas seja viável. Uma das etapas críticas é o cultivo, sendo o meio de cultura um elemento de alto custo. O objetivo principal deste trabalho é avaliar o crescimento de microalgas visando produção de lipídios para biodiesel, utilizando como fontes de nutrientes a vinhaça originada do processo produtivo de etanol no setor sucroalcooleiro. Foram isolados e indentificados três gêneros nativos de microalgas: uma cianobactéria Aphanocapsa sp., uma clorofícea Oocystis sp. e outra clorofícea Scenedesmus sp. O cultivo da microalga Scenedesmus sp. em fotobiorreator de placas planas com meio de cultivo MBM (Modified Bristol Medium) se mostrou modesta em termos de produtividade de biomassa (8 mg/l.dia) e em teor de lipídios na biomassa seca (1,5%). O cultivo dessa mesma microalga em tubos de ensaios com meio alternativo utilizando vinhaça (três diluições de 2%, 5% e 10% em volume) no meio de cultura mostrou desempenho comparável em relação ao meio sintético MBM, sendo que a partir do dia 6, os quatros cultivos se estabilizam em torno de uma concentração celular de 6×106 de células/ml, indicando que a vinhaça pode ser uma fonte de nutrientes de baixo custo para o cultivo de microalgas. Deste modo, é possível r... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

This paper examines the innovative behavior of agri-food firms located in Central and Eastern Europe. In the literature, empirical analyses on innovation activities of firms focus on various case studies from around the world. However, very few studies explored the innovation of small and medium sized enterprises (SMEs) from Central and Eastern Europe’s agri-food sector. The analysis uses the logit estimation method and firm-level data, which are obtained from ERBD-World Bank Business Environment and Enterprise Performance Survey (BEEPS). Results suggest that firms that spent some proportion of their financial budget on research and development (R&D), had workforce training programs and bought fixed assets are more likely to launch product, process, organizational and marketing innovations.

Fashion entrepreneurs with no formal fashion-related education or training are hereafter referred to by the acronym FEWFFET (fashion entrepreneurs without formal fashion-related education or training). Entrepreneurship provides a feasible means of employment in a country where national unemployment rates are alarmingly high. To succeed, entrepreneurs require business knowledge and skill to operate profitable and sustainable businesses. However, entrepreneurs who were previously disadvantaged often possess only low levels of education, limited qualifications and training. This applies to survivalist fashion entrepreneurs in the Sedibeng District Municipality (SDM) who produce various items of apparel and clothing. Over a third of these entrepreneurs are not formally educated in business management and may not possess the adequate knowledge to operate their fashion business successfully. The research aim was to investigate the uses and challenges pertaining to business skills amongst FEWFFET to determine their business skills training needs. The sample population included 105 black fashion entrepreneurs, operating micro, survivalist enterprises within peri-urban, resource-poor communities in the Emfuleni Local Municipality (ELM) of Sedibeng, Gauteng. A quantitative study using non-probability purposive sampling and snowball sampling was performed. Interviewer-administered questionnaires were conducted with respondents at fabric and haberdashery stores or within their home-business environments. The results indicated that respondents lacked business plan development skills and showed only moderate skills in finance and marketing. Respondents indicated business skills training needs for developing a business plan, conducting basic bookkeeping, determining correct product pricing, drafting quotations and invoices, developing a budget, conducting basic market research and advertising their products and services / National Research Foundation (NRF)

The future survival of small and medium enterprises (SMEs) is inextricably linked to their implementation of e-commerce systems. The lack of e-commerce strategies among SME business owners has contributed to a low level of e-commerce adoption by SMEs. The purpose of this multiple case study was to explore the strategies that Nigerian SME business owners used to implement e-commerce systems. The population consisted of retail SMEs in Lagos, Nigeria, that have functional e-commerce systems. The conceptual framework supporting the study was dynamic capabilities framework. Data for the study were derived from semistructured interviews of 4 SME business owners/managers and documentation from the case companies. Data analysis entailed coding of the interview transcripts and analysis of documentary data to identify themes. Member checking and triangulation ensured the credibility of the study. The main themes that emerged from data analysis include service delivery strategies, dynamic marketing strategies, and learning and adaptation. The implications for social change include the potential to contribute to increased wealth creation opportunities for the business owners, their employees, and the local communities in Nigeria.

Critical success factors that contribute to project success in small and medium-sized enterprises (SMEs) have received insufficient attention in research. Guided by the goal-setting conceptual framework, the purpose of this multiple case study was to explore the human resource management (HRM) strategies used by owners of SMEs to achieve project success. Five owners of SMEs in St. Lucia participated in the research by contributing their experiences in using HRM strategies to achieve project success. Data were collected from SME owners using semistructured interviews, and from observations and analysis of company records. Data were manually analyzed using Yin's 5 phases. Five themes emerged from the thematic analysis of the data obtained from the interviews, observations, and company records: (a) financial rewards, (b) team meetings and briefings, (c) training and staff enhancement, (d) retention and loyalty, and (e) work-life balance. The HRM strategies used by the participants to achieve project success have implications for social change because project success can lead to the sustainability of SMEs, thereby creating employment and improving the quality of life for citizens who benefit from the successful infrastructural and social projects that owners of SMEs undertake.

Most owners of small and medium-sized enterprises (SMEs) in Nigeria are inadequately prepared to perform the financial management tasks required for business sustainability. This case study, guided by institutional theory, was conducted to explore how SME owners can be prepared to implement financial management effectively for business sustainability in Edo state, Nigeria. The research question addressed the understanding of experienced SME owners regarding how they can develop necessary financial management skills for sustaining a business in Edo state. Data were collected using semistructured interview, and field notes from 15 SME owners in Edo state who had prior knowledge of, experience with, and education on financial management and had been managing an SME for at least 3 years. Through Yin's 5-step data analysis process, member checking, and triangulation, the themes that emerged were strategic accounting practice, knowledge of financial planning, hiring an accountant, record keeping, obtaining accounting education, and embracing technology and financial management software. The study findings have the potential to contribute to positive social change by indicating how SMEs can be more effective in generating employment, ensuring sustainability, and improving the standard of living.

Thesis (M.Dev) --University of Limpopo, 2009. / The purpose of this study was to investigate factors contributing towards the poor performance of Grade 12 learners at two selected high schools, which fall within low quintiles in Limpopo Province. Specifically, the study focused on low Grade 12 outputs in relation to access to university. Due to the exploratory nature of the study and the holistic approach that was undertaken both the home and school environments were targeted as points of investigation. Multiple methods of data collection were used. First, data were collected through individual interviews with learners, educators, principals, and parents. Second, an observation method was used to collect data, such as, time management by learners, their behavioral patterns inside and outside the classroom and in the schoolyard. Finally, document analysis was used to analyse the attendance and performance of learners on attendance registers, quarterly and half yearly schedules, and mark sheets. Key findings of this research suggest that the home environment of learners is not educationally supportive due to poverty, which includes factors such as parents’ low-level of education, high unemployment rate, child-headed families, unpredictable home environment, emotional problems and issues relating to gender roles. In the school environment, the study showed the following causative factors: lack of facilities, unavailable learner support materials, lack of discipline, English as a medium of instruction, heavy workload due to rationalisation and redeployment of educators, and confusion with regard to the application of the new curriculum (National Curriculum Statement). As a result, the study concluded that both home and school environment factors collaborate in producing poor Grade 12 results in the schools. Recommendations are made for attention to be given to these factors by all educational stakeholders. Directions are suggested for future research on poor performance and university access. / Not listed

New generations of video surveillance systems are expected to possess a large-scale network of intelligent video cameras with built-in image processing capabilities. These systems need to be tethered for reasons of bandwidth and power requirements. To support economical installation of video cameras and to manage the huge volume of information flow in these networks, there is a need for new shared-medium daisy-chained physical and medium access control (bus arbitration) layer communication protocols. This thesis describes the design principles of Spatial reuse FireWire Protocol (SFP), a novel request/grant bus arbitration protocol, architected for an acyclic daisy-chained network topology. SFP is a new extension of the IEEE 1394b FireWire architecture. SFP preserves the simple repeat path functionality of FireWire while offering two significant advantages: 1) SFP supports concurrent data transmissions over disjoint segments of the network (spatial reuse of bandwidth), which increases the effective throughput and 2) SFP provides support for priority traffic, which is necessary to handle real-time applications (like packet video), and mission critical applications (like event notifications between cameras) that have strict delay and jitter constraints. The delay and throughput performance of FireWire and SFP were evaluated using discrete-event queuing simulation models built with the CSIM-18 simulation library. Simulation results show that for a homogeneous traffic pattern SFP improves upon the throughput of IEEE 1394b by a factor of 2. For a traffic pattern typical of video surveillance applications, throughput increases by a factor of 7. Simulation results demonstrate that IEEE 1394b asynchronous stream based packet transactions offer better delay performance than isochronous transactions for variable bit rate video like MPEG-2 and MPEG-4. SFP extends this observation by supporting priority traffic. QoS for packet video is provided in SFP by mapping individual asynchronous stream packets to the three priority classes.

A produção de energia limpa e renovável é uma preocupação crescente da sociedade. Dentre as alternativas para produção de energia estão as células a combustível. Dentre os vários tipos de células, existem as PEMFC (Proton Exchange Membran Fuel Cell) que possuem vantagem de operar em baixa temperatura e podem utilizar como combustível hidrogênio ou álcoois. Porém as células PEM que utilizam álcool como combustível, ainda apresentam um rendimento inferior aquelas que operam com hidrogênio, além disso essas células requerem platina ou outros metais nobres porque somente estes materiais são relativamente estáveis nestas condições de pH. Nos últimos anos as células combustíveis alcalinas tem ganhado destaque devido à maior estabilidade dos eletrocalisadores, aumentando a possibilidade de utilização de metais não nobres ou óxidos metálicos. Neste trabalho, catalisadores do tipo Pt/C-CeO2 foram sintetizados sobre carbono de alta área superficial, variando-se a quantidade de CeO2 entre 0 a 10%. Os eletro-catalisadores contendo menor quantidade de óxidos apresentaram maior atividade frente a oxidação do etanol em meio básico. / The production of clean and renewable energy is a growing concern of society. Among the alternatives for energy production are fuel cells. Among the various types of cells, there are PEMFCs (Proton Exchange Membranes) which have the advantage of operating at low temperature and can use hydrogen or alcohols as fuel. However, PEM cells that use alcohol as fuel still have lower yields than those operating on hydrogen. In addition, these cells require platinum or other noble metals because only these materials are relatively stable under these pH conditions. In recent years alkaline fuel cells have gained prominence due to the greater stability of the electrocatalyst, increasing the possibility of using non-noble metals or metal oxides. In this work, catalysts like Pt-CeO2/C type were synthesized on carbon of high surface area, varying the amount of CeO2 between 0 and 10% (m/m). The electrocatalysts containing less oxides showed higher activity against the oxidation of ethanol in a basic medium.

La réparation de l’humain est un secteur d’activité qui nécessite les compétences en sciences médicales et sciences dites «dures». Dans de nombreux cas, tout ou partie d’un organe doit être remplacé par un substitut en matériau inerte. C’est par exemple le cas en implantologie où l’on s’intéresse au remplacement de dents. La pose d’un implant dentaire est un acte chirurgical qui consiste à introduire dans l’os de la mandibule un dispositif en matériau inerte destiné à recevoir la couronne dentaire. Ces prothèses sont plus ou moins tolérées par l’organisme vivant (environ 5% de rejet) et peuvent dans certains cas conduire à une ruine de l’os ou engendrer des infections connues sous le nom de péri-implantite. Pour améliorer la biocompatibilité de ces dispositifs médicaux, plusieurs pistes sont explorées. On peut s’intéresser à la géométrie de l’implant et son état de surface, au matériau de l’implant ou bien au système mécanique implant-os. C’est dans ce dernier cadre que nous avons situé notre travail de thèse. Le système os/dent est un système mécanique soumis à des sollicitations répétées de forte intensité. Les niveaux de contrainte et de déformation atteints lors de la mastication participent à la stabilité de l’ensemble et la viabilité de ces milieux vivants. Ces niveaux de contrainte et de déformation doivent être reproduits dans l’os dans le cas du système implant-os. On espère ainsi assurer la viabilité de l’os et éviter les divers processus de dégradation. Il convient donc de simuler et analyser la réponse d’un tel système à des sollicitations mécaniques. Ce travail nécessite la modélisation du comportement de l’os et de l’implant. Ce dernier est considéré comme un matériau métallique classique sollicité dans son domaine de déformation élastique. Pour ce qui est l’os, son observation fine révèle sa nature multi-échelle et nous avons choisi de modéliser son comportement par une particularisation du milieu micromorphique de Eringen. Plus précisément nous l’avons considéré comme un milieu élastique micropolaire. Pour résoudre les équations de champs du problème, il a été nécessaire de développer un outil numérique spécifiquement dédié. Cet outil est basé sur une combinaison astucieuse de la méthode des éléments de frontières et d’une méthode sans maillage (meshless), plus précisément une méthode de collocation par points. Dans un premier temps, afin de comprendre le principe de la méthode, nous avons développé l’outil numérique pour résoudre une équation de champ scalaire, ici équation de la conduction thermique transitoire. Nous avons pu constater l’efficacité de la méthode pour des systèmes en trois dimensions. Dans un second temps nous avons adapté notre méthode numérique pour résoudre des équations de champ vectoriel qui sont dans notre cas les équations pour les milieux élastiques micropolaires. L’outil numérique a été validé sur un nombre d’exemples possédant une solution analytique ou en comparaison aux résultats de la littérature sur d’autres types de problèmes. L’outil a ensuite été appliqué à l’analyse du système implant-os. Pour comprendre l’apport de la microstructure d’un milieu élastique micropolaire, en comparaison à un milieu élastique classique, nous avons fait différentes études du système implant-os sous sollicitations mécaniques diverses en considérant les deux types de modélisation pour l’os. Les paramètres macroscopiques pour un milieu élastique micropolaire sont les mêmes que pour un milieu élastique classique. Les différences obtenues ne proviendront que de l’apport de la microstructure. Les résultats obtenus montrent que la modélisation fine du comportement mécanique adoptée pour l’os est réaliste au regard des contraintes induites par la sollicitation et à la diminution notable des sauts de contraintes à l’interface os/métal comparé au cas de la modélisation de l’os comme un milieu élastique classique. Ces résultats ont d’ores et déjà permis de comprendre certaines observations cliniques. / The repair of the human is a sector of activity which requires skills in medical sciences and sciences known as "hard". In many cases, all or part of an organ must be replaced by a substitute made of inert material. This is for example the case in implantology where one is interested in the replacement of teeth. The installation of a dental implant is a surgical act which consists in introducing into the bone of the mandible a device made of inert material intended to receive the dental crown. These prostheses are more or less tolerated by the living organism (about 5% of rejection) and can in some cases lead to a bone ruin or cause infections known as peri-implantitis. To improve the biocompatibility of these medical devices, several tracks are explored. We can focus on the geometry of the implant and its surface condition, the material of the implant or the mechanical bone / implant system. It is in this last frame that we located our work of thesis. The bone / tooth system is a mechanical system subject to repeated intense stress. The levels of stress and deformation achieved during chewing contribute to the overall stability and viability of these living media. These stress and strain levels must be reproduced in the bone in the case of the bone / implant system. It is hoped to ensure the viability of the bone and to avoid the various processes of degradation. It is therefore necessary to simulate and analyze the response of such a system to mechanical stresses. This work requires modeling the behavior of the bone and the implant. The latter is considered as a conventional metallic material stressed in its field of elastic deformation. As for the bone, its fine observation reveals its multi-scale nature and we have chosen to model its behavior by a particularization of Eringen's micromorphic environment. More precisely we have considered it as a micropolar elastic medium. To solve the field equations of the problem, it was necessary to develop a dedicated digital tool. This tool is based on a clever combination of the boundary element method and a meshless method, more precisely a collocation method. At first, in order to understand the principle of the method, we developed the numerical tool to solve a scalar field equation, here equation of transient thermal conduction. We have seen the effectiveness of the method for three-dimensional systems. In a second time we adapted our numerical method to solve vector field equations which are in our case the equations for the micropolar elastic media. The digital tool has been validated on a number of examples having an analytical solution or in comparison with the results of the literature. The digital tool was then applied to the analysis of the bone / implant system. To understand the contribution of the microstructure of a micropolar elastic medium, compared to a conventional elastic medium, we made different studies of the implant / bone system under various mechanical stress considering both types of modeling for the bone. The macroscopic parameters for a micropolar elastic medium are the same as for a conventional elastic medium. The differences obtained will come only from the contribution of the microstructure. The results obtained show that the fine modeling of the mechanical behavior adopted for the bone is realistic with regard to the stresses induced by the stress and to the noticeable decrease of the stress jumps at the bone / metal interface compared to the case of the modeling of the equivalent classic elastic medium. These results have already made it possible to understand certain clinical observations.