Exergetic, energetic, economic and environmental evaluation of concentrated solar power plants in Libya

The PhD project addresses the potential of using concentrating solar power (CSP) plants as a viable alternative energy producing system in Libya. Exergetic, energetic, economic and environmental analyses are carried out for a particular type of CSP plants. The study, although it aims a particular type of CSP plant – 50 MW parabolic trough-CSP plant, it is sufficiently general to be applied to other configurations. The novelty of the study, in addition to modeling and analyzing the selected configuration, lies in the use of a state-of-the-art exergetic analysis combined with the Life Cycle Assessment (LCA). The modeling and simulation of the plant is carried out in chapter three and they are conducted into two parts, namely: power cycle and solar field. The computer model developed for the analysis of the plant is based on algebraic equations describing the power cycle and the solar field. The model was solved using the Engineering Equation Solver (EES) software; and is designed to define the properties at each state point of the plant and then, sequentially, to determine energy, efficiency and irreversibility for each component. The developed model has the potential of using in the preliminary design of CSPs and, in particular, for the configuration of the solar field based on existing commercial plants. Moreover, it has the ability of analyzing the energetic, economic and environmental feasibility of using CSPs in different regions of the world, which is illustrated for the Libyan region in this study. The overall feasibility scenario is completed through an hourly analysis on an annual basis in chapter Four. This analysis allows the comparison of different systems and, eventually, a particular selection, and it includes both the economic and energetic components using the “greenius” software. The analysis also examined the impact of project financing and incentives on the cost of energy. The main technological finding of this analysis is higher performance and lower levelized cost of electricity (LCE) for Libya as compared to Southern Europe (Spain). Therefore, Libya has the potential of becoming attractive for the establishment of CSPs in its territory and, in this way, to facilitate the target of several European initiatives that aim to import electricity generated by renewable sources from North African and Middle East countries. The analysis is presented a brief review of the current cost of energy and the potential of reducing the cost from parabolic trough- CSP plant. Exergetic and environmental life cycle assessment analyses are conducted for the selected plant in chapter Five; the objectives are 1) to assess the environmental impact and cost, in terms of exergy of the life cycle of the plant; 2) to find out the points of weakness in terms of irreversibility of the process; and 3) to verify whether solar power plants can reduce environmental impact and the cost of electricity generation by comparing them with fossil fuel plants, in particular, Natural Gas Combined Cycle (NGCC) plant and oil thermal power plant. The analysis also targets a thermoeconomic analysis using the specific exergy costing (SPECO) method to evaluate the level of the cost caused by exergy destruction. The main technological findings are that the most important contribution impact lies with the solar field, which reports a value of 79%; and the materials with the vi highest impact are: steel (47%), molten salt (25%) and synthetic oil (21%). The “Human Health” damage category presents the highest impact (69%) followed by the “Resource” damage category (24%). In addition, the highest exergy demand is linked to the steel (47%); and there is a considerable exergetic demand related to the molten salt and synthetic oil with values of 25% and 19%, respectively. Finally, in the comparison with fossil fuel power plants (NGCC and Oil), the CSP plant presents the lowest environmental impact, while the worst environmental performance is reported to the oil power plant followed by NGCC plant. The solar field presents the largest value of cost rate, where the boiler is a component with the highest cost rate among the power cycle components. The thermal storage allows the CSP plants to overcome solar irradiation transients, to respond to electricity demand independent of weather conditions, and to extend electricity production beyond the availability of daylight. Numerical analysis of the thermal transient response of a thermocline storage tank is carried out for the charging phase. The system of equations describing the numerical model is solved by using time-implicit and space-backward finite differences and which encoded within the Matlab environment. The analysis presented the following findings: the predictions agree well with the experiments for the time evolution of the thermocline region, particularly for the regions away from the top-inlet. The deviations observed in the near-region of the inlet are most likely due to the high-level of turbulence in this region due to the localized level of mixing resulting; a simple analytical model to take into consideration this increased turbulence level was developed and it leads to some improvement of the predictions; this approach requires practically no additional computational effort and it relates the effective thermal diffusivity to the mean effective velocity of the fluid at each particular height of the system. Altogether the study indicates that the selected parabolic trough-CSP plant has the edge over alternative competing technologies for locations where DNI is high and where land usage is not an issue, such as the shoreline of Libya.

The functional structure of the sentence: evidence from non-finite clauses

Non-finite clauses are sentential constituents with a verbal head that lacks a morphological specification for tense and agreement. In this paper I contend that these clauses are defective not only morphologically but also syntactically, in the sense that they all lack some of the functional categories that make up a full sentence. In particular I argue that to-infinitive clauses, gerund(ive) clauses and participial clauses differ among themselves, and with respect to other subordinate clauses, in the degree of structural defectiveness they display, which goes from the almost complete functional structure of the infinitive to the maximal degree of syntactic truncation of participial clauses (analyzed here as verbal small clauses). I also show the significant parallelism that exists in this respect between English and Spanish non-finite clauses, pointing to the implication this may have for a cross-linguistic approach to the cartography of syntactic structures.

Modelo de regressão beta para teste de estresse em risco de crédito de instituições financeiras

Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Estatistica, 2015.

Frecuencia de diagnóstico de ansiedad en pacientes hipertensos de 20 a 40 años que consultan en Unidad Médica de Soyapango mayo-junio 2013

La presencia de hipertensión arterial ha sido intensamente estudiada internacionalmente, así como de los trastornos de ansiedad y depresión y su relación con la hipertensión arterial, siendo así que la prevalencia global de los trastornos psíquicos se ha estimado en alrededor del 30%. En el presente estudio abarcamos la población entre 20 y 40 años con hipertensión arterial esencial y que consultan por controles o demanda espontánea en la Unidad Médica de Soyapango del Instituto Salvadoreño del Seguro Social, la muestra de 54 participantes se obtuvo por medio de la fórmula para poblaciones finitas y conocidas y se recolectó la información utilizando el método de encuesta con Escala de Goldberg para detección de casos probables de Ansiedad y Depresión, durante los meses de junio a julio de 2013 posterior a obtención de aprobación por parte de comité de ética; obteniendo como resultados casos positivos de ansiedad y depresión en un 52% y 24% respectivamente, predominante en el sexo femenino con 48%, así mismo un 53% ubicado entre las edades de 36-40 años; el 27% y 22% de casos probables a ansiedad se presentaron en sujetos con nivel escolar en primaria y bachillerato respectivamente. Con estos datos establecemos la clara comparecencia de ansiedad y depresión en pacientes jóvenes económicamente productivos con hipertensión arterial esencial y que se plantea la necesidad de realizar un estudio más amplio y homogéneo en cuanto a población para obtener datos estadísticos más representativos de las tendencias de esta dinámica en la población derechohabiente de la institución.

A ansiedade infantil : vulnerabilidades da criança e influência dos pais

Tese de Doutoramento em Psicologia na área de especialidade Psicologia Clínica

Plan de negocio para la modernización del proceso de producción de las bebidas típícas registradas con las marcas chaparro y eramón por la empresa alimentos y bebidas típicas salvadoreñas (ABTISA S.A. de C.V.)

El desarrollo del presente trabajo realizado en el Municipio de San Salvador en el periodo de Abril a Octubre del 2008, constituye la aplicación de un plan de negocio a una empresa en El Salvador que iniciará sus operaciones, en virtud de que sacará al mercado un nuevo producto, una bebida típica registrada con las marcas “Chaparro” y “Eramón”, las cuales se elaborarán modernizando su proceso de producción y se necesitará como respaldo para generar demanda. El modelo de plan de negocio presenta, en primer término, el marco teórico-conceptual para la elaboración de planes de negocios, remitiéndose a diversos libros y documentos sobre la guía de cómo llevarlo a cabo y luego su aplicación práctica a la empresa Alimentos y Bebidas Típicas Salvadoreñas S.A. de C.V. (ABTISA S.A. de C.V.). El plan de negocio se elaboró básicamente en dos etapas, en la primera, se evalúa a la empresa en su totalidad, a nivel interno y en relación con su medio ambiente para determinar el diagnóstico de la situación actual. En la otra parte se define cómo quedó establecida la empresa con sus elementos más importantes para su funcionamiento, como es la misión, visión, objetivos y metas, su estructura organizativa, su proceso de producción, las proyecciones de venta y la determinación de los indicadores financieros más relevantes. El método de investigación que se utilizó fue el método científico ya que buscó darle explicación y solución a la problemática, en su modalidad del Método Hipotético Deductivo. Tomando un universo de 59,755 habitantes del municipio de San Salvador, del cual se tomó una muestra en base a la fórmula para poblaciones finitas de muestreo por cuotas tomando un porcentaje de confianza del 95%, con probabilidad de éxito del 80%, dio como resultado 245 habitantes y el instrumento utilizado para la recolección de la información fue el cuestionario, para su posterior análisis e interpretación por medio de tablas y gráficos. Los resultados fueron la elaboración efectiva de la Propuesta del Plan de Negocios para la modernización del proceso de producción de la bebida típica registrada con las marcas “Chaparro” y “Eramón” por la empresa Alimentos y Bebidas Típicas Salvadoreñas S.A. de C.V.

A participação das forças armadas na segurança pública de Cabo Verde: que colaboração?

Tendo em conta o nível de desenvolvimento que Cabo Verde tem vindo a conhecer, o crescimento rápido da sua população, o aparecimento de novos factos criminais e ainda o facto de possuir um enorme Zona Económica Exclusiva, associado ao facto de ser um país de fracos recursos económicos, é motivo para que se optimizem os recursos, encontrando respostas legalmente adequadas, eficazes e eficientes ao fenómeno do crime e da insegurança, projectados pelas novas ameaças. Com a revisão Constitucional de 1999, as Forças Armadas (FA) ganharam competência no âmbito de segurança interna, para colaborem com as Forças e Serviços de Segurança (FSS) e sob a responsabilidade destas. Este estudo debruça sobre “A Participação das Forças Armadas na Segurança Pública em Cabo Verde”, no intuito de analisar e perceber que tipo de colaboração prevê a Constituição, perceber à que nível pode ocorrer a actuação das FA na segurança e ordem pública e quais os limites dessa actuação. Para fazer o estudo recorreu-se à análise documental e fez-se uso do método de qualitativo, tendo como instrumento de recolha de informação a entrevista (semiestruturada), seguido de uma análise de conteúdo permitindo confrontar os resultados com as ideias existentes no enquadramento teórico. Conclui-se que as FA têm competências para actuar na segurança interna somente em colaboração com as FSS. Mas mostra-se que perante o quadro socioeconómico de Cabo Verde não se pode dispensar esta colaboração.

Otimização de vazão de poços injetores em projeto de injeção de água utilizando simulação por linhas de fluxo

Until the early 90s, the simulation of fluid flow in oil reservoir basically used the numerical technique of finite differences. Since then, there was a big development in simulation technology based on streamlines, so that nowadays it is being used in several cases and it can represent the physical mechanisms that influence the fluid flow, such as compressibility, capillarity and gravitational segregation. Streamline-based flow simulation is a tool that can help enough in waterflood project management, because it provides important information not available through traditional simulation of finite differences and shows, in a direct way, the influence between injector well and producer well. This work presents the application of a methodology published in literature for optimizing water injection projects in modeling of a Brazilian Potiguar Basin reservoir that has a large number of wells. This methodology considers changes of injection well rates over time, based on information available through streamline simulation. This methodology reduces injection rates in wells of lower efficiency and increases injection rates in more efficient wells. In the proposed model, the methodology was effective. The optimized alternatives presented higher oil recovery associated with a lower water injection volume. This shows better efficiency and, consequently, reduction in costs. Considering the wide use of the water injection in oil fields, the positive outcome of the modeling is important, because it shows a case study of increasing of oil recovery achieved simply through better distribution of water injection rates

Fadiga em pacientes da Coorte Brasília de artrite reumatoide (AR) : estudo da prevalência e comparação entre diferentes instrumentos de avaliação

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Medicina, Programa de Pós-Graduação em Ciências Médicas, 2016.

Confirmação do modelo da estrutura 3D do vale inferior do Tejo a partir de dados de ruído sísmico ambiente

Ao longo de sua história a região do Vale Inferior do Tejo VIT foi abalada por vários sismos consideravelmente destrutivas, tendo alguns deles produzido significativas deformações nas estruturas marítimas localizadas no litoral a sudoeste do território Português; outros, moderados, foram produzidos por fontes locais, como os de 1344, 1531 e 1909. Nos últimos anos, devido à melhoria dos modelos de estrutura 3D e o desenvolvimento dos métodos numéricos, foram elaborados vários estudos de síntese de movimento forte do solo para a região do Baixo Tejo utilizando o método de diferenças finitas. Para confirmar o modelo de velocidades desta bacia usámos medidas de ruído sísmico, aplicámos um método baseado na razão espectral H/V, e, a partir destas curvas, por inversão, obtivemos um modelo de velocidades para a região estudada. Os resultados revelam uma boa concordância entre o modelo obtido e os dados geofísicos e geológicos recolhidos na mesma área._ ABSTRACT: Along his history the Lower Tagus Valley (LTV) area was shaken by several earthquakes. The largest reported had their origin in the southwestern part of Iberia. Other moderate earthquakes were produced by local sources such as the 1344, 1531 and the 1909. ln the last years, due to 3D structural model improvement and development in numerical methods, several studies have successful obtained strong-ground motion synthesis for the LVT region using finite difference method. To confirm the velocity model of the LTV sedimentary basin obtained by geophysical and geological data, we use broad-band microtremor measurements and application of the horizontal to vertical (H/V) spectral ratio method. We have obtained a velocity model for the studied region by inversion of the H/V curve. The results have good agreement geological and geophysical data.