Recent attempts to utilise solid particles in combination with high pressure water sprays has caused environmental and safety concern, in cleaning mineral and organic scale inside the Oil and Gas Production Tubing. To increase cleaning performance only high pressure aerated water sprays at high impact force instead should be used. Multi-nationals petroleum companies are facing immense challenges in removing the scale due to the decrease in cavitation bubbles along the production tubing when high pressure water sprays are applied. This has also resulted in high maintenance costs and low productivity of the ‘wells’ with multi billions pounds financial losses per annum. Currently scales are removed using either aggressive chemicals (acids), complete replacement of the tubing, or solid-liquid sprays which are both expensive and causes environmental concern. This research demonstrated that the application of air-water combination (aerated sprays) are the solution in complete removal of various scales in the production tubing without the use of solid particles and the cavitation bubbles. This novel experimental technique of scale removal utilised air concentration (or aeration) in combination with high pressure flat fan sprays, of up to 10 MPa, at low flow rate (up to 12 l/min) with high impact pressure of approximately 0.15 MPa, in removing scale along production tubing using a simulated aeration chamber. It was found that varying air concentration from 3 to 12%, within the emulated chamber, improved scale erosion up to 28% higher than non-aerated technique. This enabled the mass of the scale to be removed at the ‘stand-off distance’ of 25 mm relative to scale samples, irrespective of cavitation bubble length suppression which is normally about 2 mm away from the atomiser orifice exit, compared to non-aerated techniques (solids and water). Scale erosion was found to be 12.80g, 7.31 g, and 65.80 g at aerated conditions compared to non-aerated provision which found to be 9.88g, 6.33g and 5.31 g, at the required liquid pressure 10 MPa, for the hard, medium and soft scale samples that are typically found in oil production tubing. Prior to scale removal trials sprays were characterised qualitatively and quantitatively under the ambient conditions as well as inside the aerated simulated chamber. Air velocities were found to be approximately 18m/s towards the water spray centre which then decays to 3 m/s towards the spray periphery under ambient conditions using hot wire anemometer. Moreover, the flat fan sprays were also characterised utilising Phase Doppler Anemometry (PDA). It was found that the high pressure water liquid droplet velocities were in the range of 75 to 117 m/s with droplet diameters of 55 to 81 µm (SMD) at flow rates of 7.6 to 11.3 l/min at various stand-off distances of 25, 50 and 75mm, providing an impact pressure of 0.05, 0.10 and 0.15 MPa respectively. Qualitatively cavitation bubble length was also estimated using high resolution imaging techniques which were found to be between 1 to 2 mm from the atomiser exit orifice under submerged conditions, at the stand-off distance ≤ 25 mm where the scale is normally removed. Beyond this range (1-2 mm) where the cavitation bubbles are not present, that are normally the benefactors to scale removal process, requires air concentration up to 12%. This ensures that a complete removal of the mass of corresponding scales to be achieved with varying chemical scale compositions. The air concentration is the ratio of total mass of air within the simulated chamber to mass of the liquid sprays impacting directly onto the scale samples. The results of the experimental trials were used to validate the available CFD fluent models with regards to spray dynamics, aerated air (velocities), cavitation bubble generations and scale erosion (removal). The sensitivity analysis using the CFD modelling gave close comparison with those obtained through experimental trials. Spray droplets size and their velocities were found to be within ±10% compared to those obtained via experimental findings. The aerated air velocities were also compared with the data generated from CFD which were found to be approximately ±9%. Furthermore, the cavitation bubble generation and the mass of the scale removed were found to vary within ±5% and ±7% respectively, when compared to the CFD data. Finding emerged that the spray droplets especially at the centre undergoes acceleration after primary breakup, which due to higher velocities resulting from the acceleration has left the entrained-air particles behind, which is characterise with substantially low-pressure region, giving rise to utilisation of the air-water interaction model. This could be another approach in further understanding the break regions within the high pressure liquid sprays.

Os anos 1990 foram marcados pela teoria econômica que preconiza a atuação das forças de mercado, com a capacidade de atender, com qualidade e quantidade, a oferta dos serviços do setor elétrico. Entretanto, ao término dessa década e início do novo século os acontecimentos demonstraram que a teoria tem se revelado inconsistente naquilo que prometia, isto é, a crescente expansão do sistema; a inovação da tecnologia, e não promovendo a redução de custos das tarifas de energia elétrica. Os resultados alcançados no recente processo de reestruturação do setor elétrico, inspirados no livre mercado, comprovaram a inconsistência da teoria liberal, conforme constatado no desenvolvimento do presente trabalho. / The 1990s were marked by the economical theory that commended the performance of market forces with the capacity to assist, with quality and quantity, the offer of electrical energy services. However, at the end of the 1990s and beginning of the new century the data of reality demonstrated that the theory has revealed itself inconsistent in what it had promised, i.e., the system expansion; the innovation of technology, and it didn´t promote the cost reduction of electric power tariffs. The results reached in the recent process of restructuring of the electrical energy industry, inspired in the free market, prove the inconsistency of the liberal theory, as verified in the development of this thesis.

O uso eficiente de energia é reconhecido em muitos países do mundo como uma ferramenta de política energética para o desenvolvimento sustentável do setor. Este trabalho analisa a situação do uso eficiente de energia no setor elétrico chileno, cujo processo de reforma, marco legal e institucional e privatização constitui um paradigma da região. É realizada uma caracterização do setor elétrico, estuda-se o processo de reforma do setor, analisa-se o marco institucional, marco regulatório e o processo de planejamento do setor. Estudam-se a experiência, os potenciais e as principais barreiras para a eficiência energética e se propõem ações corretivas. O setor elétrico chileno apresenta potenciais de melhoramento da eficiência energética de implicação econômica, ambiental e social que não são aproveitados pela existência de diversas barreiras. A maior responsabilidade de ultrapassar estas barreiras recai no estado quem deve realizar modificações no marco institucional e propiciar a cooperação público-privada. / Efficient use of energy is recognized worldwide as an energy policy tool for a sustainable development in the sector. This work analyses the situation of energy efficiency in the Chilean electric sector, whose reform process, legal and institutional frameworks and privatization constitute a paradigm in the region. The electric sector is characterized, the reform process is studied, institutional and regulation frameworks and the planning process are analyzed. The experience, the potentials and the main barriers for energy efficiency are studied, and corrective measures are suggested. It is concluded that the Chilean electric sector presents large potential for energy efficiency improvements with economic, environmental and social impacts that are not being utilized due to the existence of several barriers. The state bears the main responsibility for overcoming these barriers by modifying the institutional framework and stimulating cooperation between the public and private sectors.

não há resumo. / There is no abstract.

O meio ambiente urbano vem sofrendo drásticas transformações ao longo destas últimas décadas. E um dos principais problemas é o aumento significativo da poluição atmosférica devido ao metabolismo realizado pela frota de veículos motorizados e indústrias instaladas nos centros urbanos. Neste trabalho, a cidade é compreendida como um sistema aberto e vista como um organismo vivo, que se alimenta de recursos naturais, realiza seu próprio metabolismo, produz resíduos, como subprodutos resultantes deste metabolismo, sob a forma de emissão gasosa, liquida e sólida que agridem e desequilibram o meio biogeofísico e afetam a comunidade al residente, bem como de regiões circunvizinhas e até bem distantes. Uma cidade ou um de seus sistemas podem ser considerados como possuidor de um metabolismo eficiente, quando consomem menos energia ou recurso natural para realizar as mesmas funções de manutenção, de geração de serviços, de crescimento urbano e de desenvolvimento sócio-econômico, produzindo menores quantidades de emissões, diminuindo os impactos negativos sobre o meio biogeofísico. Por meio de uma abordagem sistêmica e multidisciplinar, utilizado o modelo do metabolismo de uma cidade, focaliza-se no metabolismo energético do sistema de transportes. Como estudo de caso a cidade de Curitiba, estudando o metabolismo energético de seu sistema de circulação, em especial da Rede integrada de Transportes RIT, criada a partir de 1971. / In the less developed countries, the urban environment has been suffering drastic transformations in the last decades. One of the main problems from the city growth is the signicant increase of the atmospheric pollution due to emissions resulted from the metabolism of the Circulatory System, caused by traffic stream. In this work, the city is understood as an open system and seen as an alive organism that accomplishes its own metabolism: it consumes energy and material and produces residues, as resulting by-products from its metabolism. The waste disposal is in the form of gaseous, liquid and solid emissions that change the environment and affect the inhabitants of the urban areas. The city or one of its systems can accomplish an efficient metabolism, when they consume less energy or any resource to maintain its functions (generation of services, urban growth and social-economical development), producing smaller amounts of emissions and nally decreasing the negative impacts on the environment. By a systemic and multidisciplinary approach, the indicators of the metabolism of a city are used to study the energy metabolism of the transport system. The case of this study is the city of Curitiba, looking at the energy metabolism of its system of circulation, specially of RlTS - Public Transport integrated Net.

O setor de iluminação Pública (IP) do Equador representa um consumo de energia de 7% do Setor Elétrico. Uma quantidade aproximada de 450.000 luminárias existem instaladas cuja potência corresponde a 90 MW e consomem 394 GWh/ano de energia das quais 72% usam tecnologia de mercúrio, 26% tecnologia de sódio e o restante tecnologias de luz mista, incandescente e fluorescente. O potencial passível de conservação considerando as tecnologias de mercúrio e luz mista é de 66.1 MW; o maior potencial encontra-se nas luminárias HG-l75 W com 35,1 MW (53%), depois as luminárias HG- I25 W com I8,7 MW (28%). O estudo de caso propõe a substituição de luminárias de vapor de mercúrio e luz mista por vapor de sódio de alta pressão nas seguintes potências: HG-l25 W por NA-70 W; HG- 175 W por NA-I00 W; HG-250 W por NA-150 W; HG-400 W por NA-250 W; e, MS- 160 W por NA-50 W. Trocando todas as luminárias convencionais pelas respectivas eficientes (no ano atual), a potência do sistema de IP diminui para 64 MW (potência conservada de 26 MW) e, a energia diminui para 281 GWh/ano (energia conservada de 113 GWh/ano), ou seja a diminuição é 29% tanto em potência quanto em energia (diminuição de 2% do sistema elétrico). O investimento para comprar 370.000 luminárias de vapor de mercúrio e luz mista o substituir por suas equivalentes eficientes é US$ 47,7 milhões (valor anualizado de US$ 8,4 milhões/ano). Por outro lado, o valor CDVA das luminárias com potencial de conservação de energia (luminárias de vapor de mercúrio o luz mista) é de US$ 32,6 milhões/ano, com a implantação dos programas de uso eficiente de energia baixará para US$ 24,7 milhões/ano, que resulta em vantagem do ponto de vista econômico para o Equador. Além disso, o investimento inicial produz resultados satisfatórios nas figuras de mérito tais como no CEC para o elenco de substituições que situa-se em 13,2 US$/MWh, valor inferior do que o custo marginal médio de energia 83 US$/MWh. De maneira similar, o CPC situa-se em 328 US$/kW, valor inferior que qualquer alternativa de oferta de energia. Além disso, se recomenda substituir o elenco de luminárias de vapor de mercúrio e luz mista por vapor de sódio no período de três anos e obter a maior vantagem da TIR que situa-se em 46,7%. Os programas de uso eciente de energia produzem deslocamentos doa investimentos nas áreas de geração, transmissão o distribuição num valor equivalente a US$ 6,1 milhões/ano (o valor presente desta quantidade atinge US$ 33,9 milhões e é igual ao deslocamento nas instalações para produzir e transmitir energia com um custo unitário igual ao marginal de potência). A poupança pela diminuição de potência e do consumo de energia atinge US$ 9,4 milhões/ano (US$ 6,1 milhões por potência e US$ 3,3 milhões por energia). No entanto, os custos operacionais aumentam em US$ 1,5 milhões/ano. Portanto, o balanço abrangente de perdas e ganhos proporciona um saldo positivo de US$ 7.9 milhões/ano (o valor presente é US$ 44,6 milhões). / Equador´s Public illumination (PI) is responsible for 7% of the total electric energy consumption of the Electric Sector: There are nearly 450,000 lamps installed, with an electric power demand of 90 MW and a consumption of 394 GWh/year of energy. Mercury lamps represent 72% of the consumption, sodium lamps represent 26% and the remaining is used by mix, incandescent and uorescent lamps. The expected saving of capacity with the retrotting of mercury and mix lamps is 66.1 MW. The greater saving is for the lamps HG-l 75W with 35.1 MW (53%) and the lamps HG-l25W with l8.7 MW (28%). This thesis propose to replace mercury vapor and mix lights by high pressure sodium lamps with the following power: HG-125W by NA-70W; HG-I75W by NA-100W; HG-250W by NA- 150W; HG-400W by NA-250W and MS-160W by NA-50W. If conventional technology is replaced by the efficient one (at this moment), dernand capacity of the PI system decrease to 64 MW (power conservation, 26 MW), energy consumption to 281 GWh/year (saved energy of 113 (GWh/year), that is a decrease of 29% for the power and electric systems requirements (electric system decrease in 2%). To change 370,000 mercury and mix lamps by the eicient lights needs US$ 47.7 millions (annualized US$ 8.4 millions/year). The Annualized Life-cycle Cost of the potential conservation of energy (mercury vapor lamps and mix lights) is US$ 32.6 millions/year. This replacement decrease by US$ 24.7 millions/year the electricity bill of the sector showing that Equador has economic gain. Besides that, the initial investment shows advantage on merit figures as the Cost Saved Energy for the alternatives of substitution of 13.2 US$/MWh, that is lower than the energy marginal cost of 83 US$/MWh. Identically the Cost Saved Power is 328 US$/kW that is lower than any other supply option. The recommendation is to distribute the replacement during three years carrying out the substitution of the conventional lamps as they extinguished obtaining a best advantage in the Internal Rate of Return of 46.7%. The substitution program (energy efficient use) produces a displacement of investments in the generation, transmission and distribution areas with a value of US$ 6.1 millions/year (this amount is similar to the displacement of installation of more system electric power at an initial cost US $ 33.9 millions). Saved power and energy represents an amount US$ 9.4 rnillions/year (US$ 6.1 millions by power and US$ 3.3 millions by energy). However the operation cost increases by US$ 1.5 millions/year, therefore the balance including costs and gains has a net positive balance of US$ 7.9 millions/year (present value represents US$ 44.6 millions).

This thesis focuses on the design and implementation of the Portable DC Light Bulb system for Cal Poly San Luis Obispo’s DC House Project. The DC Portable Light Bulb highlights the NiMH battery charging circuit, buck converter, and boost converter. The system is intended as a flashlight adaptor placed in between the dimmable DC light bulb and its screw base. The adaptor adds a portability feature to the DC light bulb to provide lighting wherever the user pleases. The Portable DC Light Bulb system is designed to operate with an input range of 24V-60V and regulate an output voltage of 34V for the DC light bulb. Computer simulations, calculations, and hardware results verifies the proposed Portable DC Light Bulb system’s design, function, and purpose.

As the energy demand grows so to do the need for devices that can be tailored to a design need. Often, this can lead to a device that falls between the two traditional groups of lithium-ion battery (LIB) and lithium-ion capacitors (LIC). An emerging way to bring these devices together is using composite cathodes. Composite cathodes combine a battery material with capacitor material and have shown to be able to enhance life cycle energy and power performance compared to their non-composite counterparts. The initial focus of the investigation is into the performance impact of LiNi0.5Co0.2Mn0.3O2 (NMC) as an additive to Activated Carbon (AC) electrodes within a high-performance Li-ion capacitor fabricated with activated carbon positive electrodes (PEs) and hard carbon negative electrodes (NEs) having lithium thin film as Li sources loaded on the surface of the negative electrodes. We report here on a hybrid LIC consisting of a Lithium nickel cobalt manganese oxide /activated carbon composite cathode in combination with an ultra-thin lithium film (u-Li) pre-loaded hard carbon anode. Additionally, we show that by utilizing three design approaches: dry composite electrode fabrication method, cathode to anode capacity ratio design, and pre-lithiation method using u-Li, we can demonstrate an energy storage device with excellent cycle life, and that can be tailored by composite ratios within the cathode to fit different applications. Shown here is an in-depth look at various composite material ratios, pre-lithiation calculations, and hybrid lithium-ion battery-capacitor energy storage device creation based on targeting essential energy-power performance characteristics. / A Dissertation submitted to the Department of Electrical and Computer Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Spring Semester 2019. / April 17, 2019. / cycle life, dry method composite hybrid cathode, Hybrid Li-ion battery-capacitor, lithium nickel cobalt manganese oxide, pre-lithiation, Ragone plots / Includes bibliographical references. / Jim P. Zheng, Professor Directing Dissertation; Chiang Shih, University Representative; Petru Andrei, Committee Member; Simon Y. Foo, Committee Member; Hui Li, Committee Member.

No description available.

Source: Dissertation Abstracts International, Volume: 35-07, Section: B, page: 3390. / Thesis (Ph.D.)--The Florida State University, 1974.