Otimização de estruturas de destilação azeotrópica com recurso a planeamento experimental

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Química e Biológica

Controlo preditivo distribuído para conforto térmico em edifícios

Dissertação para obtenção do grau de Mestre em Engenharia Electrotécnica Ramo de Automação e Electrónica Industrial

RadiaLE: A framework for designing and assessing link quality estimators in wireless sensor networks

Stringent cost and energy constraints impose the use of low-cost and low-power radio transceivers in large-scale wireless sensor networks (WSNs). This fact, together with the harsh characteristics of the physical environment, requires a rigorous WSN design. Mechanisms for WSN deployment and topology control, MAC and routing, resource and mobility management, greatly depend on reliable link quality estimators (LQEs). This paper describes the RadiaLE framework, which enables the experimental assessment, design and optimization of LQEs. RadiaLE comprises (i) the hardware components of the WSN testbed and (ii) a software tool for setting-up and controlling the experiments, automating link measurements gathering through packets-statistics collection, and analyzing the collected data, allowing for LQEs evaluation. We also propose a methodology that allows (i) to properly set different types of links and different types of traffic, (ii) to collect rich link measurements, and (iii) to validate LQEs using a holistic and unified approach. To demonstrate the validity and usefulness of RadiaLE, we present two case studies: the characterization of low-power links and a comparison between six representative LQEs. We also extend the second study for evaluating the accuracy of the TOSSIM 2 channel model.

Optimizing the renewable generation mix in the Portuguese power system based on temporal and spatial diversity

Renewable energy sources (RES) have unique characteristics that grant them preference in energy and environmental policies. However, considering that the renewable resources are barely controllable and sometimes unpredictable, some challenges are faced when integrating high shares of renewable sources in power systems. In order to mitigate this problem, this paper presents a decision-making methodology regarding renewable investments. The model computes the optimal renewable generation mix from different available technologies (hydro, wind and photovoltaic) that integrates a given share of renewable sources, minimizing residual demand variability, therefore stabilizing the thermal power generation. The model also includes a spatial optimization of wind farms in order to identify the best distribution of wind capacity. This methodology is applied to the Portuguese power system.

Optimizing the renewable generation mix in the portuguese power system based on temporal and spatial diversity

Renewable energy sources (RES) have unique characteristics that grant them preference in energy and environmental policies. However, considering that the renewable resources are barely controllable and sometimes unpredictable, some challenges are faced when integrating high shares of renewable sources in power systems. In order to mitigate this problem, this paper presents a decision-making methodology regarding renewable investments. The model computes the optimal renewable generation mix from different available technologies (hydro, wind and photovoltaic) that integrates a given share of renewable sources, minimizing residual demand variability, therefore stabilizing the thermal power generation. The model also includes a spatial optimization of wind farms in order to identify the best distribution of wind capacity. This methodology is applied to the Portuguese power system.

Scale-free networks and scalable interdomain routing

Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia Informática

Simple and stable dynamic traffic engineering for provider scale ethernet

Trabalho apresentado no âmbito do Mestrado em Engenharia Informática, como requisito parcial para obtenção do grau de Mestre em Engenharia Informática

Development of new methodologies in sample treatment for proteomics workflow based on enzymatic probe sonication technology and mass spectrometry

Thesis submitted to the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia, for the degree of Doctor of Philosophy in Biochemistry

Otimização Energética na Produção de Biodiesel

Enquadrado num contexto cada vez mais marcado pela necessidade imperiosa de adoção e desenvolvimento de práticas ambientais e energeticamente sustentáveis, este trabalho visa contribuir para a caracterização e otimização do consumo de energia na produção de biodiesel. O biodiesel pode ser encarado como uma boa resposta aos graves problemas que os combustíveis fósseis estão a provocar nas sociedades modernas, pois é uma fonte de energia biodegradável, não-tóxica e sintetizada a partir de várias matérias-primas. Porém, o elevado custo de produção, como consequência do elevado preço das matérias-primas, constitui o maior problema para a sua implementação e comercialização a grande escala. A produção de biodiesel é, em sua quase totalidade, conduzida por via de reação de transesterificação, usando óleo vegetal e álcool como matérias-primas. O objetivo geral deste trabalho é otimizar energeticamente um processo de produção de biodiesel, via catálise homogênea alcalina (BCHA). Para alcançar esse objetivo, um fluxograma típico de produção foi construído e analisado, tanto do ponto de vista energético como econômico. Posteriormente oportunidades de otimização do processo foram identificadas, no sentido de reduzir o consumo de utilidades, impacto ambiental e aumentar a rentabilidade econômica. A construção do processo, a caracterização da alimentação, os critérios de operacionalidade, a obtenção de resultados e demais fatores foram efetuados com auxílio de um software de simulação Aspen Plus versão 20.0 criado pela Aspen Technology products. Os resultados do trabalho revelaram que o processo BCHA produz uma corrente com 99,9 % em biodiesel, obedecendo às normas internacionais em vigor. Na parte energética, o processo BCHA base necessitou de 21.405,1 kW em utilidades quentes e 14.886,3 kW em utilidades frias. A integração energética do processo BCHA, segundo a metodologia pinch, permitiu uma redução das necessidades quentes para 10.752,3 kW (redução de 50 %) e frias para 4.233,5 kW (redução de 72 %). A temperatura no ponto de estrangulamento (PE) foi de 157,7 ºC nas correntes quentes e 147,7 ºC nas correntes frias. Em termos econômicos, o custo total é reduzido em 35% com a integração energética proposta. Essa diminuição, deve-se sobretudo à redução do custo operacional, onde as necessidades de vapor de muita alta pressão (VMAP), vapor de alta pressão (VAP) e água de resfriamento (AR) apresentaram quebras de 2 %, 92 % e 71 %, respectivamente. Como conclusão final, salienta-se que a integração do processo BCHA estudado é energética e economicamente viável.

Distributed processing of large remote sensing images using MapReduce - A case of Edge Detection

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

Epidemic store for massive scale systems

The MAP-i doctoral program of the Universities of Minho, Aveiro and Porto

Cross-scale determinants of palm species distribution

We investigate palm species distribution, richness and abundance along the Mokoti, a seasonally-dry river of southeastern Amazon and compare it to the patterns observed at a large scale, comprising the entire Brazilian territory. A total of 694 palms belonging to 10 species were sampled at the Mokoti River basin. Although the species showed diverse distribution patterns, we found that local palm abundance, richness and tree basal area were significantly higher from the hills to the bottomlands of the study region, revealing a positive association of these measures with moisture. The analyses at the larger spatial scale also showed a strong influence of vapor pressure (a measure of moisture content of the air, in turn modulated by temperature) and seasonality in temperature: the richest regions were those where temperature and humidity were simultaneously high, and which also presented a lower degree of seasonality in temperature. These results indicate that the distribution of palms seems to be strongly associated with climatic variables, supporting the idea that, by 'putting all the eggs in one basket' (a consequence of survival depending on the preservation of a single irreplaceable bud), palms have become vulnerable to extreme environmental conditions. Hence, their distribution is concentrated in those tropical and sub-tropical regions with constant conditions of (mild to high) temperature and moisture all year round.

Benefits from energy related building renovation beyond costs, energy and emissions

The relevance of the building sector in the global energy use as well as in the global carbon emissions, both in the developed and developing countries, makes the improvement of the overall energy performance of existing buildings an important part of the actions to mitigate climate changes. Regardless of this potential for energy and emissions saving, large scale building renovation has been found hard to trigger, mainly because present standards are mainly focused on new buildings, not responding effectively to the numerous technical, functional and economic constraints of the existing ones. One of the common problems in the assessment of building renovation scenarios is that only energy savings and costs are normally considered, despite the fact that it has been long recognized that investment on energy efficiency and low carbon technologies yield several benefits beyond the value of saved energy which can be as important as the energy cost savings process. Based on the analysis of significant literature and several case studies, the relevance of co-benefits achieved in the renovation process is highlighted. These benefits can be felt at the building level by the owner or user (like increased user comfort, fewer problems with building physics, improved aesthetics) and should therefore be considered in the definition of the renovation measures, but also at the level of the society as a whole (like health effects, job creation, energy security, impact on climate change), and from this perspective, policy makers must be aware of the possible crossed impacts among different areas of the society for the development of public policies.

Development of a methodology to incorporate risk and uncertainty in electricity power planning

Dissertação de mestrado em Engenharia Industrial

Otimização de custos, consumos energéticos e emissões de gases com efeito de estufa na reabilitação de edifícios residenciais de baixa densidade

Dissertação de mestrado integrado em Engenharia Civil