Determinantes do sucesso das iniciativas empresariais apoiadas pelo microcrédito

Dissertação de Mestrado apresentada ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Contabilidade e Finanças sob orientação de: Amélia Ferreira da Silva “Esta versão contém as críticas e sugestões dos elementos do júri”

A estruturação dos determinantes relevantes no processo de decisão do investimento direto estrangeiro em Portugal e em Espanha

Dissertação de Mestrado apresentada ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Contabilidade e Finanças, sob orientação do Dr. Luís Pereira Gomes

Fatores determinantes do (in)sucesso de clínicas/gabinetes particulares com a valência de terapia da fala nos distritos de Porto e Aveiro

A presente dissertação apresenta o resultado de uma pesquisa realizada, através da recolha de dados, nos distritos do Porto e Aveiro, onde foram analisados os fatores determinantes do (in)sucesso estratégico de clínicas/gabinetes (CG) particulares com a valência de terapia da fala (TF). Inicia com a apresentação de algumas considerações conceptuais relativas à empresa, organização e inovação. De seguida, são descritos os principais passos a dar em Portugal para a constituição de uma empresa e é feita uma abordagem aos temas da viabilidade estratégica de um projeto e do conceito de plano de negócios. A parte teórica do presente projeto de investigação encerra com os fatores de sucesso e insucesso empresarial descritos na literatura. Neste trabalho, procura-se analisar as principais determinantes de sobrevivência das novas empresas ligadas à área da TF. Para tal, procedeu-se à recolha de dados junto de proprietários e/ou gestores de CG particulares com TF, nos distritos de Porto e Aveiro, selecionados a partir da base de dados da Entidade Reguladora da Saúde (ERS), das Páginas Amarelas Online e da Internet com as palavraschave: “clínicas, gabinetes, terapia da fala”. Os resultados estatisticamente tratados e analisados evidenciam a importância dos seguintes fatores como estatisticamente significativos para o sucesso de uma CG privada com TF nos distritos de Porto e Aveiro: maior antiguidade da CG, maior número de utentes, de concorrentes e de TF a trabalhar, assim como a realização de rastreios na área da TF. Fatores como: proprietário com formação na área da gestão, maior número de valências, publicidade e acessibilidades na CG, parecem contribuir para o aumento das hipóteses de sobrevivência de CG particulares com TF nos distritos de Porto e Aveiro, ainda que não sejam estatisticamente significativos. Em contrapartida, a falta de um plano de negócios parece ser um fator que influencia o insucesso destas CG.

Multi-agent simulation of continental, regional, and micro electricity markets

Renewable based power generation has significantly increased over the last years. However, this process has evolved separately from electricity markets, leading to an inadequacy of the present market models to cope with huge quantities of renewable energy resources, and to take full advantage of the presently existing and the increasing envisaged renewable based and distributed energy resources. This paper proposes the modelling of electricity markets at several levels (continental, regional and micro), taking into account the specific characteristics of the players and resources involved in each level and ensuring that the proposed models accommodate adequate business models able to support the contribution of all the resources in the system, from the largest to the smaller ones. The proposed market models are integrated in MASCEM (Multi- Agent Simulator of Competitive Electricity Markets), using the multi agent approach advantages for overcoming the current inadequacy and significant limitations of the presently existing electricity market simulators to deal with the complex electricity market models that must be adopted.

Optimal scheduling of a renewable micro-grid in an isolated load area using mixed-integer linear programming

In the energy management of the isolated operation of small power system, the economic scheduling of the generation units is a crucial problem. Applying right timing can maximize the performance of the supply. The optimal operation of a wind turbine, a solar unit, a fuel cell and a storage battery is searched by a mixed-integer linear programming implemented in General Algebraic Modeling Systems (GAMS). A Virtual Power Producer (VPP) can optimal operate the generation units, assured the good functioning of equipment, including the maintenance, operation cost and the generation measurement and control. A central control at system allows a VPP to manage the optimal generation and their load control. The application of methodology to a real case study in Budapest Tech, demonstrates the effectiveness of this method to solve the optimal isolated dispatch of the DC micro-grid renewable energy park. The problem has been converged in 0.09 s and 30 iterations.

Determinantes da dor e do desconforto durante a mamografia

Objectivo: Medir a intensidade de dor e desconforto aquando da mamografia, e identificar os determinantes associados a estes sintomas. Métodos: 150 utentes responderam a um questionário pré e pós exame, que permitiu quantificar a dor e desconforto durante a mamografia, e encontrar os determinantes relacionados com estes sintomas. Resultados: 88% referiu dor na realização do exame, a ansiedade foi um factor preponderante e o conforto pré exame permitiu que menos mulheres sentissem dor. Conclusão: A generalidade dos dados analisados concorda com a revisão da literatura. Excepções: utilização de contraceptivos orais e realização de Terapia Hormonal de Substituição.

Banco de ensaios para micro geração eólica

Mestrado em Engenharia Electrotécnica e de Computadores

Diversity and characterisation of coagulasenegative staphylococci isolated from healthy individuals in Portugal

In the past few years the interest in coagulase-negative staphylococci (CoNS) has significantly increased in human medicine. CoNS are common commensal colonisers of the human skin, although now also recognised as major nosocomial pathogens. Over the last decades, several studies have been carried out in order to understand the pathogenicity mechanisms of CoNS. The well known determinants in the pathogenesis of CoNS infections are their ability to form biofilms and an exceptional resistance to several antibiotics. Nevertheless, there is a lack of studies regarding the commensal lifestyle of these microorganisms. Additionally, it is now hypothesised that commensal bacteria might be a reservoir of pathogenic determinants. Therefore, the work described throughout this thesis was aimed to perform a phenotypic and genotypic characterisation of different CoNS species isolated from healthy Portuguese individuals. A total of 61 CoNS isolates, comprising 7 different species, were obtained and characterised at the level of biofilm formation and antibiotic susceptibility profiles. According to the results, biofilm formation ability and presence of biofilm-associated genes were commonly found features, highlighting their pivotal role in the colonising lifestyle of CoNS. This study also addressed the correlation between phenotypic and genotypic characteristics of biofilm formation, corroborating and raising questions about the importance of some genes in this process. Moreover, it was observed a great proportion of isolates with decreased susceptibility and multiple resistances to some important antibiotics. A significant association between antibiotic resistance and biofilm formation was also demonstrated, and some hypotheses about the nature of such association were provided. Lastly, the expression patterns of two biofilm-associated genes at two distinct biofilm developmental stages were determined, confirming their importance in the accumulative stage of biofilm formation. Overall, the results presented in this thesis indicate that staphylococcal skin flora might be an important reservoir of potentially pathogenic bacteria and, simultaneously, bring to light new perceptions about the molecular basis of staphylococcal biofilm formation, and the nature of the association between antibiotic resistance and biofilm formation.

Estudo técnico relativo à instalação de micro eólicas em edifícios urbanos para microprodução de energia eléctrica

O Planeta Terra tem vindo a ser fustigado pelas alterações climáticas resultado da poluição ambiental provocada pelo Homem. Com o objectivo de minimizar estes efeitos deletérios, os países mais desenvolvidos estabeleceram compromissos relativamente às emissões de gases com efeito de estufa, tendo por base o Protocolo de Kyoto. A iniciativa «Renováveis na Hora» é uma das medidas previstas no plano para a política de energia e alterações climáticas, apresentado em Fevereiro de 2008, pelo Ministério da Economia e da Inovação Português. Actualmente, em Portugal, existe um mercado emergente para a microgeração, que se rege segundo a legislação aplicada recentemente, que estabelece o novo regime jurídico aplicável à produção de energia por intermédio de unidades de microprodução. Esta iniciativa levará à criação de um novo paradigma de exploração e utilização de energia. Deste modo, é fundamental avançar com alguns alertas das condições de exploração. A energia eólica é umas das fontes renováveis em que o rendimento de conversão pode atingir valores interessantes (poderá ser superior a 50%) e em determinadas regiões o seu potencial é bastante bom, nomeadamente em zonas litorais e em zonas montanhosas. Em ambiente urbano é impraticável a instalação de grandes torres eólicas, mas a micro produção baseada em pequenas turbinas eólicas é perfeitamente possível e desejável. O propósito deste trabalho é realizar um estudo de cariz técnico acerca da instalação de um mini parque eólico num edifício urbano, tendo em conta todas as condicionantes (velocidade do vento, obstáculos na zona, altura de montagem, inter-distância entre aerogeradores). Foi realizado um software que irá auxiliar a escolha dos aerogeradores e inversores para o tipo de local onde vai ser instalado o parque eólico.

Os determinantes do crédito comercial: um estudo sobre as empresas industriais portuguesas

O presente trabalho procura testar empiricamente algumas teorias sobre os motivos pelos quais as empresas concedem e recebem crédito comercial. Para este efeito usa- se um painel de 11040 empresas portuguesas, das quais 360 são grandes empresas e 10680 são PME, para o período compreendido entre 2003 e 2009. Apesar da relevância do crédito comercial como fonte de financiamento empresarial, o tema está longe de se considerar esgotado, sobretudo porque não existe uma teoria geral sobre este assunto. Assim, o nosso trabalho procura contribuir para a literatura que estuda os determinantes para a concessão e recebimento de crédito comercial. Adicionalmente, e porque esta temática não têm sido muito estudada em Portugal, pretendemos analisar o papel do crédito comercial como fonte de financiamento das empresas portuguesas. No presente trabalho conclui-se que as grandes empresas (com maior acesso ao mercado de crédito) servem como intermediários financeiros para os seus clientes com menor acesso ao financiamento. Para além disso, observou-se que as empresas fornecedoras utilizam o crédito comercial como um meio legal de discriminação de preços. Por fim, as empresas financeiramente constrangidas, principalmente em momentos de crise financeira, recorrem ao crédito comercial como fonte alternativa de financiamento, corroborando a hipótese de substituição entre o crédito comercial e o crédito bancário.

Self-mated tribological systems based on multilayer micro/nanocrystalline CVD diamond coatings

The tribological response of multilayer micro/nanocrystalline diamond coatings grown by the hot filament CVD technique is investigated. These multigrade systems were tailored to comprise a starting microcrystalline diamond (MCD) layer with high adhesion to a silicon nitride (Si3N4) ceramic substrate, and a top nanocrystalline diamond (NCD) layer with reduced surface roughness. Tribological tests were carried out with a reciprocating sliding configuration without lubrication. Such composite coatings exhibit a superior critical load before delamination (130–200 N), when compared to the mono- (60–100 N) and bilayer coatings (110 N), considering ∼10 µm thick films. Regarding the friction behaviour, a short-lived initial high friction coefficient was followed by low friction regimes (friction coefficients between 0.02 and 0.09) as a result of the polished surfaces tailored by the tribological solicitation. Very mild to mild wear regimes (wear coefficient values between 4.1×10−8 and 7.7×10−7 mm3 N−1 m−1) governed the wear performance of the self-mated multilayer coatings when subjected to high-load short-term tests (60–200 N; 2 h; 86 m) and medium-load endurance tests (60 N; 16 h; 691 m).

Role of abrasive material on micro-abrasion wear tests

Micro-abrasion wear tests with ball-cratering configuration are widely used. Sources of variability are already studied by different authors and conditions for testing are parameterized by BS EN 1071-6: 2007 standard which refers silicon carbide as abrasive. However, the use of other abrasives is possible and allowed. In this work, ball-cratering wear tests were performed using four different abrasive particles of three dissimilar materials: diamond, alumina and silicon carbide. Tests were carried out under the same conditions on a steel plate provided with TiB2 hard coating. For each abrasive, five different test durations were used allowing understanding the initial wear phenomena. Composition and shape of abrasive particles were investigated by SEM and EDS. Scar areas were observed by optical and electronic microscopy in order to understand the wear effects caused by each of them. Scar geometry and grooves were analyzed and compared. Wear coefficient was calculated for each situation. It was observed that diamond particles produce well-defined and circular wear scars. Different silicon carbide particles presented dissimilar results as consequence of distinct particle shape and size distribution.

Adhesion and wear behaviour of NCD coatings on Si3N4 by micro-abrasion tests

Nanocrystalline diamond (NCD) coatings offer an excellent alternative for tribological applications, preserving most of the intrinsic mechanical properties of polycrystalline CVD diamond and adding to it an extreme surface smoothness. Silicon nitride (Si3N4) ceramics are reported to guarantee high adhesion levels to CVD microcrystalline diamond coatings, but the NCD adhesion to Si3N4 is not yet well established. Micro-abrasion tests are appropriate for evaluating the abrasive wear resistance of a given surface, but they also provide information on thin film/substrate interfacial resistance, i.e., film adhesion. In this study, a comparison is made between the behaviour of NCD films deposited by hot-filament chemical vapour deposition (HFCVD) and microwave plasma assisted chemical vapour deposition (MPCVD) techniques. Silicon nitride (Si3N4) ceramic discs were selected as substrates. The NCD depositions by HFCVD and MPCVD were carried out using H2–CH4 and H2–CH4–N2 gas mixtures, respectively. An adequate set of growth parameters was chosen for each CVD technique, resulting in NCD films having a final thickness of 5 m. A micro-abrasion tribometer was used, with 3 m diamond grit as the abrasive slurry element. Experiments were carried out at a constant rotational speed (80 r.p.m.) and by varying the applied load in the range of 0.25–0.75 N. The wear rate for MPCVD NCD (3.7±0.8 × 10−5 m3N−1m−1) is compatible with those reported for microcrystalline CVD diamond. The HFCVD films displayed poorer adhesion to the Si3N4 ceramic substrates than the MPCVD ones. However, the HFCVD films show better wear resistance as a result of their higher crystallinity according to the UV Raman data, despite evidencing premature adhesion failure.

Influence of the abrasive particles size in the micro-abrasion wear tests of TiAlSiN thin coatings

Ball rotating micro-abrasion tribometers are commonly used to carry out wear tests on thin hard coatings. In these tests, different kinds of abrasives were used, as alumina (Al2O3), silicon carbide (SiC) or diamond. In each kind of abrasive, several particle sizes can be used. Some studies were developed in order to evaluate the influence of the abrasive particle shape in the micro-abrasion process. Nevertheless, the particle size was not well correlated with the material removed amount and wear mechanisms. In this work, slurry of SiC abrasive in distilled water was used, with three different particles size. Initial surface topography was accessed by atomic force microscopy (AFM). Coating hardness measurements were performed with a micro-hardness tester. In order to evaluate the wear behaviour, a TiAlSiN thin hard film was used. The micro-abrasion tests were carried out with some different durations. The abrasive effect of the SiC particles was observed by scanning electron microscopy (SEM) both in the films (hard material) as in the substrate (soft material), after coating perforation. Wear grooves and removed material rate were compared and discussed.