Automated Generation of Indoor Accessibility Information for Mobility-Impaired Individuals

Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies.

Barriers to micro-enterprise development

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Cellulose micro/nano fibers conformational effects probed by nematic liquid crystal droplets

Probing micro-/nano-sized surface conformations, which are ubiquitous in biological systems, by using liquid crystal droplets, which change their ordering and optical appearance in response to the presence of more than ten times smaller cellulose based micro/nano fibers, might find new uses in a range of biological environments and sensors. Previous studies indicate that electrospun micro/nano cellulosic fibers produced from liquid crystalline solutions could present a twisted form [1]. In this work, we study the structures of nematic liquid crystal droplets threaded by cellulose fibers prepared from liquid crystalline and isotropic solutions as well as droplets pierced by spider-made fibers [2]. Planar anchoring at the fibers and planar and homeotropic at the drop surfaces allowed probing cellulose fibers different helical structures as well as aligned filaments.

Writing/erasing 3D micro and nano wrinkles in flexible elastomers for volatile organic compounds sensor

Micro/nano wrinkled patterns on cross-linked urethane/urea polymeric flexible free standing films with two soft segments, polypropylene oxide and polybutadiene, can be induced by UV-irradiation. The ability to write/erase these 3D structures, in a controlled manner, is the main focus of this work. The imprinting of the wrinkled structures was accomplished by swelling in an appropriate solvent followed by drying the membranes after the cross-linking process and UV irradiation. The surface tailoring of the elastomeric membranes was imaged by optical microscopy, scanning electronic microscopy and by atomic force microscopy. To erase the wrinkled structures the elastomers were swollen. The swelling as well as the sol/gel fraction and the UV radiation were tuned in order to control the wrinkles characteristics. It was found that the wrinkles wavelength, in the order of microns (1±0,25μm), was stamped by the UV radiation intensity and exposure time while the wrinkles' amplitude, in the order of nanometers (150-450 nm), was highly dependent on the swelling and sol/gel fraction. A prototype for volatile organic compounds detection was developed taking advantage of the unique 3D micro/nano wrinkles features.

Construção de Sistemas Integrados de Gestão para Micro e Pequenas Empresas

As Micro e Pequenas Empresas (MPE) possuem na sua essência recursos limitados. Raramente possuem um Sistema Integrado de Gestão (SIG) que lhes permita gerir o seu negócio de forma transversal e que mapeie todos os processos da empresa. Devido ao número reduzido de colaboradores, não dispõem internamente alguns serviços. O seu espaço de mercado é em geral limitado. As suas competências específicas raramente permitem apresentar uma oferta global. Por serem pequenas, não têm força negocial perante os seus fornecedores e eventuais parceiros estratégicos. A Arquitetura de Sistemas de Informação (ASI) permite representar e mapear os diversos aspetos da gestão das empresas e alinhar as Tecnologias de Informação e Comunicação (TIC) com as necessidades destas empresas. Este trabalho pretende apresentar e descrever uma Macro Arquitetura para a construção de SIG, orientados para as MPE, e que inclua um conjunto de serviços integrados numa única plataforma.

A model to screen and improve business potential of micro and small enterprises in developing countries: Evidence from the Island of Mozambique

Programmes supporting micro and small enterprises in developing countries have been showing that capital is not enough to allow business success: survival and growth. Literature does not provide comprehensive and practical tool to support business development in this context, but allowed the collection of forty-nine success variables that were studied in a sample of successful and unsuccessful businesses in the Island of Mozambique to discover what were the key factors affecting those businesses’ performance. Empirical data gave the insights for the development of a model to screen and improve business potential of micro and small enterprises in this context.

Experimental and modeling studies on reverse electrodialysis for sustainable power generation

A potentially renewable and sustainable source of energy is the chemical energy associated with solvation of salts. Mixing of two aqueous streams with different saline concentrations is spontaneous and releases energy. The global theoretically obtainable power from salinity gradient energy due to World’s rivers discharge into the oceans has been estimated to be within the range of 1.4-2.6 TW. Reverse electrodialysis (RED) is one of the emerging, membrane-based, technologies for harvesting the salinity gradient energy. A common RED stack is composed by alternately-arranged cation- and anion-exchange membranes, stacked between two electrodes. The compartments between the membranes are alternately fed with concentrated (e.g., sea water) and dilute (e.g., river water) saline solutions. Migration of the respective counter-ions through the membranes leads to ionic current between the electrodes, where an appropriate redox pair converts the chemical salinity gradient energy into electrical energy. Given the importance of the need for new sources of energy for power generation, the present study aims at better understanding and solving current challenges, associated with the RED stack design, fluid dynamics, ionic mass transfer and long-term RED stack performance with natural saline solutions as feedwaters. Chronopotentiometry was used to determinate diffusion boundary layer (DBL) thickness from diffusion relaxation data and the flow entrance effects on mass transfer were found to avail a power generation increase in RED stacks. Increasing the linear flow velocity also leads to a decrease of DBL thickness but on the cost of a higher pressure drop. Pressure drop inside RED stacks was successfully simulated by the developed mathematical model, in which contribution of several pressure drops, that until now have not been considered, was included. The effect of each pressure drop on the RED stack performance was identified and rationalized and guidelines for planning and/or optimization of RED stacks were derived. The design of new profiled membranes, with a chevron corrugation structure, was proposed using computational fluid dynamics (CFD) modeling. The performance of the suggested corrugation geometry was compared with the already existing ones, as well as with the use of conductive and non-conductive spacers. According to the estimations, use of chevron structures grants the highest net power density values, at the best compromise between the mass transfer coefficient and the pressure drop values. Finally, long-term experiments with natural waters were performed, during which fouling was experienced. For the first time, 2D fluorescence spectroscopy was used to monitor RED stack performance, with a dedicated focus on following fouling on ion-exchange membrane surfaces. To extract relevant information from fluorescence spectra, parallel factor analysis (PARAFAC) was performed. Moreover, the information obtained was then used to predict net power density, stack electric resistance and pressure drop by multivariate statistical models based on projection to latent structures (PLS) modeling. The use in such models of 2D fluorescence data, containing hidden, but extractable by PARAFAC, information about fouling on membrane surfaces, considerably improved the models fitting to the experimental data.

Otimização da técnica de micro Fluorescência de Raios- X para o estudo de ossos

Nos países desenvolvidos, as doenças reumáticas são o grupo de doenças mais fre-quentes da espécie humana, sendo por isso o primeiro motivo de consulta nos cuidados de saúde primários e a principal causa de incapacidade temporária para o trabalho e de reformas antecipadas por doença/invalidez (Canhão & Branco, 2013). O estudo destas doenças torna-se cada vez mais urgente visto que estas têm tendência crescente, tendo em conta os atuais esti-los de vida e o aumento da longevidade da população. Nesta dissertação foi estudada e otimi-zada a técnica de Micro Fluorescência de Raios-X (μ-XRF) de forma a permitir um estudo de elementos maioritários e elementos traço em ossos com doenças reumáticas, tendo em espe-cial atenção a razão Ca/P, já que, por estudos até agora efetuados, esta razão é considerada um biomarcador adequado para a avaliação da saúde dos ossos. Foram então verificados os erros aleatórios e sistemáticos existentes nesta técnica e concluiu-se quais os tipos de parâme-tros que devem ser tidos em conta para este estudo, tais como corrente, tensão do tubo, filtros, entre outros. As amostras foram ainda analisadas com a técnica de PIGE (Particle Induced Gamma-ray Emission) e comparados os resultados com os de μ-XRF de forma a avaliar a in-fluência da topologia da amostra. Pretende-se que este estudo seja o início do desenvolvimen-to de um método alternativo de diagnóstico precoce de doenças reumáticas, conduzindo a um tratamento mais eficaz e melhorando assim a qualidade de vida da população.

Phage display as a tool for generation of bio-therapeutic agents for breast cancer

Notch is a conserved signalling pathway, which plays a crucial role in a multiple cellular processes such as stem cell self-renewal, cell division, proliferation and apoptosis. In mammalian, four Notch receptors and five ligands are described, where interaction is achieved through their extracellular domains, leading to a transcription activation of different target genes. Increased expression of Notch ligands has been detected in several types of cancer, including breast cancer suggesting that these proteins represent possible therapeutic targets. The goal of this work was to generate quality protein targets and, by phage display technology, select function-blocking antibodies specific for Notch ligands. Phage display is a powerful technique that allows the generation of highly specific antibodies to be used for therapeutics, and it has also proved to be a reliable approach in identifying and validating new cancer-related targets. Also, we aimed at solving the tri-dimensional structure of the Notch ligands alone and in complex with selected antibodies. In this work, the initial phase focused on the optimization of the expression and purification of a human Delta-like 1 ligand mutant construct (hDLL1-DE3), by refolding from E. coli inclusion bodies. To confirm the biological activity of the produced recombinant protein cellular functional studies were performed, revealing that treatment with hDLL1-DE3 protein led to a modulation of Notch target genes. In a second stage of this study, Antibody fragments (Fabs) specific for hDLL1-DE3 were generated by phage display, using the produced protein as target, in which one good Fab candidate was selected to determine the best expression conditions. In parallel, multiple crystallization conditions were tested with hDLL1-DE3, but so far none led to positive results.

Alpha generation with Twitter’s daily momentum

This thesis does not set out to focus on the dynamics relationship between Twitter and stock prices, but instead tries to understand if using relevant information extracted from tweets has the power to increase investors’ stock picking ability, and generate alpha in portfolio’s choice relative to a benchmark. Despite the short period analyzed, it gives promising results that the sentiment analysis performed by Social Market Analytics Inc. applied to an equity portfolio, is able to generate positive abnormal returns, statistically significant in and out of sample.

Caraterização metrológica de contadores de micro caudal

Nas últimas décadas, as empresas têm sido sujeitas a uma maior concorrência, ao desenvolvimento tecnológico mais acelerado e a novos desafios no que respeita à qualidade. A Metrologia deverá assim acompanhar estas tendências do mercado. O Departamento de Metrologia (DMET) do Instituto Português da Qualidade, I.P. (IPQ) tem vindo a desenvolver esforços significativos que visam a melhoria contínua das técnicas e dos processos de medição e de calibração realizados nos laboratórios. A presente dissertação de mestrado foi realizada no Laboratório de Volume e Caudal (LVC) do DMET. Os objetivos iniciais do trabalho centraram-se na caraterização metrológica de contadores de fluidos, tendo como base a medição do caudal, utilizando como método de referência o método gravimétrico. De forma a validar o sistema de medição foram realizados ensaios entre 1 mL/h a 100 mL/h, em condições de reprodutibilidade, com dois sistemas padrão distintos de acordo com o caudal a ensaiar. Em todos os ensaios efetuados foi necessário monitorizar as condições ambientais, i.e. temperatura, pressão atmosférica, humidade relativa e a temperatura do líquido padrão, para a aplicação das correções necessárias. Outro feito importante foi a caraterização das fontes de incerteza, que permitiram caraterizar o resultado das medições. A metodologia utilizada para a avaliação e para a estimativa da incerteza de medição encontra-se descrita no Guide to the Expression of Uncertainty in Measurement (GUM). Neste projeto foram contempladas fontes de incerteza como as associadas à evaporação, à impulsão do tubo, à resolução da balança, entre outras. Com os resultados obtidos foi possível elaborar um procedimento técnico para a Calibração de Caudalímetros de Líquidos. Os resultados obtidos permitiram garantir a rastreabilidade das medições de caudal de líquidos ao SI, essencial para a calibração de equipamentos no Laboratório Nacional de Metrologia (LNM) do IPQ, nomeadamente para micro caudalímetros no intervalo de medição entre 0,12 mL/h e 600 mL/h.