Production of biodiesel from the resources endogeneous of Timor Leste

Os biocombustíveis têm estado na linha da frente das políticas energéticas mundiais visto que as suas vantagens conseguem colmatar as incertezas e resolver alguns dos problemas associados aos combustíveis fósseis. O biodiesel tem provado ser um combustível muito fiável, alternativo ao petrodiesel. É uma mistura de ésteres alquílicos produzidos a partir de óleos vegetais e gorduras animais através de uma reacção de transesterificação. Como combustível, o biodiesel é economicamente viável, socialmente responsável, tecnicamente compatível e ambientalmente amigável. O principal desafio associado ao seu desenvolvimento tem a ver com a escolha de matéria-prima para a sua produção. Nos países do terceiro mundo, óleos alimentares são mais importantes para alimentar pessoas do que fazer funcionar carros. Esta tese tem como objectivos produzir/processar biodiesel a partir de recursos endógenos de Timor-Leste e medir/prever as propriedades termodinâmicas do biodiesel, a partir das dos esteres alquílicos. A síntese do biodiesel a partir dos óleos de Aleurites moluccana, Jatropha curcas e borras de café foram aqui estudados. As propriedades termodinâmicas como densidade, viscosidade, tensão superficial, volatilidade e velocidade do som também foram medidas e estimadas usando modelos preditivos disponíveis na literatura, incluindo as equações de estado CPA e soft-SAFT. Timor-Leste é um país muito rico em recursos naturais, mas a maioria da população ainda vive na pobreza e na privação de acesso a serviços básicos e condições de vida decentes. A exploração de petróleo e gás no mar de Timor tem sido controlado pelo Fundo Petrolífero. O país ainda carece de electricidade e combustíveis que são cruciais para materializar as políticas de redução da pobreza. Como solução, o governo timorense criou recentemente o Plano Estratégico de Desenvolvimento a 20 anos cujas prioridades incluem trazer o desenvolvimento do petróleo do mar para a costa sul de Timor-Leste e desenvolver as energias renováveis. É neste último contexto que o biodiesel se insere. O seu desenvolvimento no país poderá ser uma solução para o fornecimento de electricidade, a criação de empregos e sobretudo o combate contra a pobreza e a privação. Para ser usado como combustível, no entanto, o biodiesel deve possuir propriedades termodinâmicas coerentes com as especificadas nas normas da ASTM D6751 (nos Estados Unidos) ou EN 14214 (na Europa) para garantir uma adequada ignição, atomização e combustão do biodiesel no motor.

Vaness: DNS for nomadic users in vehicular networks

Vehicular networks, also known as VANETs, are an ad-hoc network formed by vehicles and road-side units. Nowadays they have been attracting big interest both from researchers as from the automotive industry. With the upcoming of automotive specific operating systems and self-driving cars, the use of applications on vehicles and the integration with common mobile devices is becoming a big part of VANETs. Although many advances have been made on this field, there is still a big discrepancy between the communication layer services provided by VANETs and the user level services, namely those accessible through mobile applications on other networks and technologies. Users and developers are accustomed to user-to-user or user-tobusiness communication without explicit concerns related with the available communication transport layer. Such is not possible in VANETs since people may use more than one vehicle. However, to send a message to a specific user in these networks, there is a need to know the ID of the vehicle where the user is, meaning that there is a lack of services that map each individual user to VANETs endpoint (vehicle identification). This dissertation work proposes VANESS, a naming service as a resource to support user-to-user communication within a heterogeneous scenario comprising typical ISP scenario and VANETs focused on mobile devices. The proposed system is able to map the user to an end point either locally (i.e. there is not internet connection at all), online (i.e. system is not in a vehicular network but has direct internet connection) and using a gateway (i.e. the system is in a vehicular network where some of the nodes have internet access and will act as a gateway). VANESS was fully implemented on android OS with results proving his viability, and partially on iOS showing its multiplatform capabilities.

Development of variable displacement oil pump for internal combustion engines

In the last years the need to develop more environmentally friendly and efficient cars as led to the development of several technologies to improve the performance of internal combustion engines, a large part of the innovations are focused in the auxiliary systems of the engine, including, the oil pump, this is an element of great importance in the dynamics of the engine as well a considerable energy consumer. Most solutions for oil pumps to this day are fixed displacement, for medium and high speeds, the pump flow rate is higher than the needs of the engine, this excess flow leads to the need for recirculation of the fluid which represents a waste of energy. Recently, technological advances in this area have led to the creation of variable displacement oil pumps, these have become a 'must have' due to the numerous advantages they bring, although the working principle of vane or piston pumps is relatively well known, the application of this technology for the automotive industry is new and brings new challenges. The focus of this dissertation is to develop a new concept of variable displacement system for automotive oil pumps. The main objective is to obtain a concept that is totally adaptable to existing solutions on the market (engines), both dimensionally as in performance specifications, having at the same time an innovative mechanical system for obtaining variable displacement. The developed design is a vane pump with variable displacement going in line with existing commercial solutions, however, the variation of the eccentricity commonly used to provide an variable displacement delivery is not used, the variable displacement is achieved without varying the eccentricity of the system but with a variation of the length of the pumping chamber. The principle of operation of the pump is different to existing solutions while maintaining the ability to integrate standard parts such as control valves and mechanical safety valves, the pump is compatible with commercial solutions in terms of interfaces for connection between engine systems and pump. A concept prototype of the product was obtained in order to better evaluate the validity of the concept. The developed concept represents an innovation in oil pumps design, being unique in its mechanical system for variable displacement delivery.

Distribuição de conteúdos em redes veiculares usando mecanismos de comunicação tolerantes ao atraso

The last couple of decades have been the stage for the introduction of new telecommunication networks. It is expected that in the future all types of vehicles, such as cars, buses and trucks have the ability to intercommunicate and form a vehicular network. Vehicular networks display particularities when compared to other networks due to their continuous node mobility and their wide geographical dispersion, leading to a permanent network fragmentation. Therefore, the main challenges that this type of network entails relate to the intermittent connectivity and the long and variable delay in information delivery. To address the problems related to the intermittent connectivity, a new concept was introduced – Delay Tolerant Network (DTN). This architecture is built on a Store-Carry-and-Forward (SCF) mechanism in order to assure the delivery of information when there is no end-to-end path defined. Vehicular networks support a multiplicity of services, including the transportation of non-urgent information. Therefore, it is possible to conclude that the use of a DTN for the dissemination of non-urgent information is able to surpass the aforementioned challenges. The work developed focused on the use of DTNs for the dissemination of non-urgent information. This information is originated in the network service provider and should be available on mobile network terminals during a limited period of time. In order to do so, four different strategies were deployed: Random, Least Number of Hops First (LNHF), Local Rarest Bundle First (LRBF) e Local Rarest Generation First (LRGF). All of these strategies have a common goal: to disseminate content into the network in the shortest period of time and minimizing network congestion. This work also contemplates the analysis and implementation of techniques that reduce network congestion. The design, implementation and validation of the proposed strategies was divided into three stages. The first stage focused on creating a Matlab emulator for the fast implementation and strategy validation. This stage resulted in the four strategies that were afterwards implemented in the DTNs software Helix – developed in a partnership between Instituto de Telecomunicac¸˜oes (IT) and Veniam R , which are responsible for the largest operating vehicular network worldwide that is located in Oporto city. The strategies were later evaluated on an emulator that was built for the largescale testing of DTN. Both emulators account for vehicular mobility based on information previously collected from the real platform. Finally, the strategy that presented the best overall performance was tested on a real platform – in a lab environment – for concept and operability demonstration. It is possible to conclude that two of the implemented strategies (LRBF and LRGF) can be deployed in the real network and guarantee a significant delivery rate. The LRBF strategy has the best performance in terms of delivery. However, it needs to add a significant overhead to the network in order to work. In the future, tests of scalability should be conducted in a real environment in order to confirm the emulator results. The real implementation of the strategies should be accompanied by the introduction of new types of services for content distribution.