This thesis is to develop a new ocean-wave-energy acquisition system. This system is composed of a float plate, a buoy, a nearly resonant vibrator, a dynamotor, and an oil pressure system. The whole system can be divided into two sub-systems by its function: energy generation system or vibration reduction system. Each of them can generate energy from ocean wave and reduce the vibration of flow plate. After simplifying the dynamic model and optimization analysis, we will discuss with the influence of parameters on the amount of energy and the vibration reduction. Energy generation system want to the maximum power by optimizing system parameters (mass of the buoy, mass of the nearly resonant vibrator, the coefficient of spring, and the coefficient of generator). Here we will use four kinds of optimization methods. In the first three methods, we want to find the suitable parameters to make system to generate the maximum power at an operation of frequency wave. These three methods are different from the request of the relation phase of displacement between the buoy and the nearly resonant vibrator. The fourth method, we want to find the parameters of system, which can generate power evenly at each of frequency in a range of frequency wave motion. The work is done by searching for minimum variance of power. Vibration reduction system can reduce the vibration of float plate by optimizing parameter. After simplifying and making some assumptions, system can be simplified approximately to a vibration absorber at a specific frequency. There is no displacement at that frequency, but there are displacements on the other frequency of the operation range. In order to let system to apply properly in a range of frequency, we find the minimum one that is the maximum displacement in the range of frequency. After optimization design, we can get each result from these two sub-systems. From the first three methods of energy generation system, all energy distributes on the around of operation frequency. There are no frequencies on the others of the operation range. Moreover, the displacement of each body in this system is too large to apply. By the fourth method, energy-frequency curve is evenly on the operation range. Overall, the average of energy is larger than that of frequency of system whose design concept from first three methods. The displacements of each body in this system are small enough to apply. In vibration reduction system, we search the parameters in the optimization methods. The results show that vibration reduction just occurs around the operation frequency and the others in the range not

This study involves the investigation of the early actinide systems using ab initio techniques based on density functional theory (DFT). It was motivated by: (i) the incomplete description of these systems using conventional DFT because they are strongly correlated, (ii) the usefulness of these systems in nuclear energy generation, (iii) the complexity that arises in experimentally studying these systems due to their inherent radioactive nature and (iv) their limited availability. The results obtained from this study are divided into two broad sections. The first comprises chapters 3 and 4 while the second comprises chapters 5 and 6. Thorium based compounds are studied in chapters 3 and 4. In the first section, the Hubbard U parameter is not necessary to accurately describe the electronic, elastic and mechanical properties of these systems. In the second, the inclusion of the Hubbard U parameter is shown to be paramount for the accurate description of most compounds considered. Chapter 3 presents the electronic, structural and bonding character of thorium based nitrides. We obtained the result that Th2N2NH, which is crystallographically equivalent to metallic Th2N3, is insulating. Chapter 4 demonstrates that the formation of a meta-stable thorium-titanium based alloy is plausible and also further information on bonding, electronic and elastic properties of the determined meta-stable alloy is provided. This has provided important new knowledge about these bulk systems. In Chapter 5 the DFT + U based study on Pa and its oxides is presented. The electronic, structural and bonding character of these systems was studied. We found that PaO2 is a Mott-Hubbard insulator with an indirect band gap of 3.48 eV within the generalized gradient approximation GGA + U. Chapter 6 discusses various actinide nitrides. We explored the electronic properties, elastic properties, lattice dynamics and the energetics of the various compounds using GGA + U. Also, we investigated the e ect of the Hubbard U parameter and magnetic configuration on these systems. The use of the DFT + U based method provides a rapid way to study strongly correlated systems, while other methods such as Hybrid functional,GW, DMFT+DFT, etc. are highly intensive, computationally speaking. Finally, the results obtained with the inclusion of this ad hoc parameter give a very good description of these systems. / Thesis (PhD)--University of Pretoria, 2014. / gm2014 / Physics / unrestricted

Quick and early detection of abnormalities in the body's metabolism is of paramount importance to monitor, control, and prevent the associated diseases and pathologies. Biosensors technology is rapidly advancing, from the first electronic biosensor reported by Clark and Lyons in 1962 for blood glucose monitoring to today’s devices that can detect multiple metabolites in bodily fluids continuously and simultaneously within seconds. This rapid growth in point-of-care devices promises for the development of novel devices with different form factors and the ability to detect a wide range of biomarkers. These advancements mainly stem from the development of electronic materials that have properties better aligning with the biotic interface compared to the traditional metal electrodes. A promising class of electronic materials for biosensors is conjugated polymers. Conjugated polymers are carbon-based, organic semiconducting materials made of long chains comprising conjugated repeat units. The fundamental property that makes these materials so attractive is, however, not their electronic conductivity, but their ionic conductivity. As living organisms use ionic fluxes to relay signals, materials that can conduct ionic currents are believed to facilitate the communication between the electronics and living systems. This communication happens at various levels: organs, complex tissues, cells, cell membrane, proteins, and small biomolecules. Besides, the inherently soft nature of these materials facilitates mechanical conformity with soft biological systems. The field of organic bioelectronics has experienced tremendous growth over the past two decades, thanks to the design of new conjugated polymers customized for the biotic interface. While hole conducting (p-type) polymers have been widely investigated, electron conducting (n-type) counterparts are relatively new. This dissertation aims to explore the capabilities of n-type conjugated polymers for bioelectronics applications. Chapter 1 overviews the key properties of conjugated polymers and the resulting electronic devices that leverage these properties for specific applications in bioelectronics. Chapter 2 presents microfabricated metabolite (lactate and glucose) sensors based on an n-type polymer in combination with enzymes, and how this communication can enable energy production from bodily fluids. Finally, Chapter 3 reports the development of engineering and design strategies to enhance the performances of n-type polymers in bioelectronics.

Piezoelectric energy harvesters in the road pavement are developed and studied to collect energy from the passing vehicles. A numerical model based on the Westergaard's stress model is proposed to calculate the three dimensional stress distribution in the pavement and the power generation from the piezoelectric harvesters placed inside the pavement. Piezoelectric patch, plate and beam harvesters are designed. Based on proposed numerical models, simulations are conducted to reveal the effects of vehicle velocity as well as the location and size of the Piezo-electric harvesters on the generated power. Optimally designed plate energy harvester attached with four cantilever harvesters generates up to around 28 W electrical power with the assumption of continuum vehicle passing the pavement by 22.2 m/s. This power can be used to collect enough energy in 2 hours to raise the ice temperature with the thickness of 1 cm, covering a 5 m wide road by 20 degree Celsius. / February 2017

Astrophysical models that address stellar energy generation and nucleosynthesis require a considerable amount of input from nuclear physics and are very sensitive to the detailed structure of nuclei, both stable and unstable. Radioactive nuclei play a dominant role in several stellar environments such as supernovae, X-ray bursts, novae etc. and nuclear data are important in the interpretation of these phenomena. When carbon, nitrogen and oxygen isotopes are present in substantial quantities in a star of sufficient mass, the fusion of four hydrogen nuclei to form a helium nucleus proceeds via the CNO cycles. Energy release in the CNO cycles is limited by the long lifetimes of 14O and 15O. In explosive stellar scenarios such as X-ray bursts, the energy output is very large, suggesting a breakout from the CNO cycles. 15O(α,γ)19Ne is the first reaction that breaks out of the CNO cycle. Nuclear structure information on high lying states in 19Ne is required to calculate the rate of the 15O(α,γ)19Ne reaction. This work focuses on the study of states in 19Ne above 3.53 MeV. The lifetimes of five states in 19Ne above 3.53 MeV were measured in this work. The states in 19Ne were populated via the 3He(20Ne,α)19Ne reaction at a beam energy of 34 MeV. The lifetimes were measured using the Doppler Shift Attenuation Method. The lifetimes of five states were measured and an upper limit was set on the lifetime of a sixth state. Three of the measurements are the most precise thus far. The lifetimes of the other three states agree with the values of the only other measurement of the lifetimes of these states. An upper limit on the rate of the 15O(α,γ)19Ne reaction was calculated at the 90% confidence level using the measured lifetimes. The contributions to the 15O(α,γ)19Ne reaction rate from several states in 19Ne at different stellar temperatures are discussed.

Astrophysical models that address stellar energy generation and nucleosynthesis require a considerable amount of input from nuclear physics and are very sensitive to the detailed structure of nuclei, both stable and unstable. Radioactive nuclei play a dominant role in several stellar environments such as supernovae, X-ray bursts, novae etc. and nuclear data are important in the interpretation of these phenomena. When carbon, nitrogen and oxygen isotopes are present in substantial quantities in a star of sufficient mass, the fusion of four hydrogen nuclei to form a helium nucleus proceeds via the CNO cycles. Energy release in the CNO cycles is limited by the long lifetimes of 14O and 15O. In explosive stellar scenarios such as X-ray bursts, the energy output is very large, suggesting a breakout from the CNO cycles. 15O(α,γ)19Ne is the first reaction that breaks out of the CNO cycle. Nuclear structure information on high lying states in 19Ne is required to calculate the rate of the 15O(α,γ)19Ne reaction. This work focuses on the study of states in 19Ne above 3.53 MeV. The lifetimes of five states in 19Ne above 3.53 MeV were measured in this work. The states in 19Ne were populated via the 3He(20Ne,α)19Ne reaction at a beam energy of 34 MeV. The lifetimes were measured using the Doppler Shift Attenuation Method. The lifetimes of five states were measured and an upper limit was set on the lifetime of a sixth state. Three of the measurements are the most precise thus far. The lifetimes of the other three states agree with the values of the only other measurement of the lifetimes of these states. An upper limit on the rate of the 15O(α,γ)19Ne reaction was calculated at the 90% confidence level using the measured lifetimes. The contributions to the 15O(α,γ)19Ne reaction rate from several states in 19Ne at different stellar temperatures are discussed.

Orientador: Luiz Antonio Rossi / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-25T15:35:36Z (GMT). No. of bitstreams: 1 Rodrigues_RafaelValotta_M.pdf: 1796516 bytes, checksum: c10125b5f3d629834ab44f3d7dc88632 (MD5) Previous issue date: 2014 / Resumo: A participação da energia eólica na matriz elétrica brasileira vem aumentando continuamente desde 2005. A conexão de Aerogeradores de Grande Porte à rede elétrica foi permitida após a regulamentação do setor eólico no Brasil pela ANEEL, culminando com o crescimento contínuo do setor nos últimos cinco anos e a consolidação da participação da fonte eólica na matriz elétrica brasileira. O interesse pela utilização de Aerogeradores de Pequeno Porte no país aumentou, posto que sua conexão com a rede elétrica foi regulamentada pela ANEEL através da resolução 482. Acompanhando a evolução do uso de aerogeradores, metodologias para avaliação e simulação do desempenho de aerogeradores foram extensivamente desenvolvidas no século passado. Uma delas é o Método do Momento no Elemento de Pá, um modelo numérico unidimensional desenvolvido inicialmente por Glauert em 1920, utilizado para aferir o desempenho aerodinâmico do rotor do aerogerador. Neste trabalho, as curva de desempenho de potência e curvas adimensionais de desempenho de dois aerogeradores de pequeno porte foram simuladas teoricamente utilizando o Método do Momento no Elemento de Pá. Posteriormente, a aplicação desses aerogeradores na situação de conexão com a rede elétrica ou em um sistema isolado eólico-baterias foi simulada por meio do programa computacional Homer, considerando três cidades diferentes: Campinas e Cubatão (Brasil/SP) e Roscoe (Estados Unidos / TX). O aerogerador nacional possui melhor desempenho aerodinâmico em baixas rotações, enquanto que o importado possui coeficiente de potência mais alto em altas rotações. Além disso, o aerogerador nacional produz mais energia elétrica para todas as localidades analisadas com exceção da cidade de Campinas (SP/BR), onde o aerogerador importado obteve melhor desempenho simulado. Considerando o sistema isolado eólico - baterias, a garantia de suprimento integral à carga elétrica simulada só é alcançada com um banco de baterias com muitas unidades e alto número de aerogeradores devido à intermitência da fonte eólica. O desempenho aerodinâmico do rotor e o custo da energia ($/kWh) dependem fortemente das características técnicas do aerogerador e do recurso eólico local / Abstract: The use of the wind energy in the Brazilian energy matrix has been increasing since 2005. The connection of large wind generators to the grid was allowed after the regulation of the wind industry in Brazil by ANEEL, resulting in the continued growth of the sector over the past five years, and the consolidation of the use of wind energy in the Brazilian energy matrix. Interest in the use of Small Wind Turbines (SWT) in the country has grown, since the regulation of its connection to the energy grid by ANEEL by the 482 resolution. Following the evolution of wind turbine using, methodologies to evaluation and simulation of wind turbine performance were extensively developed last century. One of them is the numeric one-dimensional model based on the Blade Element Moment Method, first developed last century by Glauert to derive aerodynamic performance of wind turbine rotor. In this research, the power performance curve and non-dimensional performance curves of two small wind turbines of horizontal axis were evaluated simulated theoretically using the Blade Element Moment Method. Afterwards, the application of the wind turbines for on-grid and off-grid systems was simulated using the software Homer, considering three different cities: Campinas and Cubatão (Brazil/SP) and Roscoe (United States/TX). The national wind turbine has better aerodynamic performance in lower rotations, while the imported has higher power coefficient in higher rotations. Also, the national wind turbine produces more electric energy for all locations evaluated excepting for Campinas City (SP/BR), where the imported wind turbine had better simulated performance. Considering the off-grid wind batteries system, the full supply can be reached only using a bank battery with many units and several wind turbines due to the intermittency of the wind energy. The rotor aerodynamic performance and the cost of energy ($/kWh) depend strongly of the technical characteristics and the local wind resource / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Agrícola

Astrophysical models that address stellar energy generation and nucleosynthesis require a considerable amount of input from nuclear physics and are very sensitive to the detailed structure of nuclei, both stable and unstable. Radioactive nuclei play a dominant role in several stellar environments such as supernovae, X-ray bursts, novae etc. and nuclear data are important in the interpretation of these phenomena. When carbon, nitrogen and oxygen isotopes are present in substantial quantities in a star of sufficient mass, the fusion of four hydrogen nuclei to form a helium nucleus proceeds via the CNO cycles. Energy release in the CNO cycles is limited by the long lifetimes of 14O and 15O. In explosive stellar scenarios such as X-ray bursts, the energy output is very large, suggesting a breakout from the CNO cycles. 15O(α,γ)19Ne is the first reaction that breaks out of the CNO cycle. Nuclear structure information on high lying states in 19Ne is required to calculate the rate of the 15O(α,γ)19Ne reaction. This work focuses on the study of states in 19Ne above 3.53 MeV. The lifetimes of five states in 19Ne above 3.53 MeV were measured in this work. The states in 19Ne were populated via the 3He(20Ne,α)19Ne reaction at a beam energy of 34 MeV. The lifetimes were measured using the Doppler Shift Attenuation Method. The lifetimes of five states were measured and an upper limit was set on the lifetime of a sixth state. Three of the measurements are the most precise thus far. The lifetimes of the other three states agree with the values of the only other measurement of the lifetimes of these states. An upper limit on the rate of the 15O(α,γ)19Ne reaction was calculated at the 90% confidence level using the measured lifetimes. The contributions to the 15O(α,γ)19Ne reaction rate from several states in 19Ne at different stellar temperatures are discussed. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Energy occupies a pivotal position in the development and progress of today's society. From the daily lives of residents to international transportation, the limited non-renewable energy resources on the earth are being exhausted. With increasing world energy demand and the shortage of fossil fuels, solar energy has become a key technology to solve energy problems. Compared with the serious pollution caused by fossil fuels, solar energy is clean and free. Nowadays, countries around the world are rapidly developing solar energy technology to alleviate the crisis caused by energy shortages. As a major oil producer and exporter, the United Arab Emirates (UAE) attached great importance to develop and utilize solar energy. The directed project investigated the feasibility and sustainability of developing solar energy in the UAE. The unique geographical location of the UAE gives it an absolute advantage in solar energy harvesting. However, the environment in the desert also affects the utilization of solar panels to a certain extent. The research performed data analysis on solar radiation and environmental factors to discuss the development prospects of solar energy in the UAE. Although the research has existing limitations, the strategic goal of sustainable development of solar energy never changes. Based on data and cost-effectiveness analysis, the directed research made recommendations to accept or decline the project.

Conventional energy sources are not only finite and depleting rapidly, but are a major source of global warming because they are key contributors of greenhouse gases to the atmosphere. Renewable energy sources are one important approach to these challenges. Distributed micro-generation energy sources are expected to increase the diversity of energy sources for the grid, but also increase the flexibility and resilience of the grid. Furthermore, it could reduce the domestic energy demand from the grid by enabling local consumption of energy generated through renewable sources. The most widely installed renewable energy generation systems in domestic environments, in UK, are based on solar power. However, there is a common recurring issue related to output intermittency of most promising renewable energy generation methods (e.g. solar and wind), resulting in a temporal energy mismatch between local energy generation and energy consumption. Current state-of-the-art technologies/solutions for tackling temporal energy mismatch rely on various types of energy storage technologies, most of which are not suitable for the domestic environments because they are designed for industrial scale application and relatively costly. As such energy storage system technologies are generally not deemed as economically viable or attractive for domestic environments. This research project seeks to tackle the temporal energy mismatch problem between local PV generated energy and domestic energy consumption without the need for dedicated energy storage systems; without affecting the householders comfort and/or imposing operational burdens on the householders. Simulation has been chosen as the major vehicle to facilitate much of the research investigation although data collated from related research projects in the UK and Jordan have been used in the research study. Solar radiation models have been established for predicting the solar radiation for days with clear-sky for any location at any time of the year. This model has achieved a correlation factor of 0.99 in relating to the experimental data-set obtained from National Energy Research Centre Amman/Jordan. Such a model is an essential component for supporting this research study, which has been employed to predict the amount of solar power that could be obtained in different locations and different day(s) of the year. A Domestic Energy Ecosystem Model (DEEM) has been established, which is comprised of two sub-models, namely “PV panels” and “domestic energy consumption” models. This model can be configured with different parameters such as power generation capacity of the photovoltaic (PV) panels and the smart domestic appliances to model different domestic environments. The DEEM model is a vital tool for supporting the test, evaluation and validation of the proposed temporal energy mismatch control strategies. A novel temporal energy mismatch control strategy has been proposed to address these issues by bringing together the concepts of load shifting and energy buffering, with the support of smart domestic appliances. The ‘What-if’ analysis approach has been adopted to facilitate the study of ‘cause-effect’ under different scenarios with the proposed temporal energy mismatch control strategy. The simulation results show that the proposed temporal energy mismatch control strategy can successfully tackle the temporal energy mismatch problem for a 3 bedroom semi-detached house with 2.5kWp PV panels installed, which can utilise local generated energy by up to 99%, and reduce the energy demand from the grid by up to 50%. Further analysis using the simulation has indicated significant socio-economic impacts to the householders and the environment could be obtained from the proposed temporal energy mismatch control strategy. It shows the proposed temporal energy mismatch control strategy could significantly reduce the annual grid energy consumption for a 3 bedrooms semi-detached house and produce significant carbon reductions.