959 resultados para GRAVITY
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Foram realizados três experimentos com o objetivo de avaliar o efeito da suplementação de minerais na forma orgânica na dieta de codornas japonesas na fase de postura sobre o desempenho e a qualidade de ovos das aves. Os níveis de minerais utilizados por kg de ração, para cada experimento, foram: controle, 0,35, 0,70 e 1,05mg de Se orgânico (experimento 1); controle, 50, 100 e 150mg de Zn orgânico (experimento 2) e controle, 60, 120 e 180mg de Mn orgânico (experimento 3). As aves foram distribuídas em delineamento inteiramente ao acaso, sendo oito aves por parcela e seis repetições por tratamento. Foram avaliadas as características de desempenho - consumo diário de ração, peso dos ovos, porcentagem de postura, conversão alimentar por massa de ovos e por dúzia de ovos e viabilidade - e qualidade dos ovos - unidade Haugh, índice gema, porcentagens de casca, albúmen e gema, espessura de casca e gravidade específica. O Zn orgânico suplementado à dieta melhorou o desempenho das aves e a qualidade dos ovos, o Mn orgânico melhorou a qualidade da casca e reduziu o peso dos ovos e o Se não apresentou efeitos sobre as características avaliadas.
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An experiment was conduced to evaluate the inclusion of sunflower meal (SBM) in commercial layer diets formulated on total or digestible amino acids basis. One hundred forty-four 41-week-old Lohmann LSL layers were distributed in a completely randomized experimental design in a 2 x 4 factorial arrangement with three replications of six birds each. Treatments consisted of a combination of four SBM inclusion levels SBM(0%, 4%, 8%, and 12%) and feed formulation according two amino acid recommendations (total or digestible). The experimental period was divided into five periods of fourteen days. Performance parameters (egg production, feed intake, feed conversion, egg mass) were evaluated for each period. In the last two days of each period, three eggs per replication were collected to evaluate egg quality (Haugh units, specific gravity, egg weight, eggshell thickness, and eggshell percentage). Hens fed on total amino acid recommendation presented the highest values for egg weight. Diets formulated on digestible amino acids basis showed an improvement in eggshell percentage and egg specific gravity. SBM addition in commercial layer diets did not influence performance; however, increasing SBM dietary levels SBM improved eggshell quality.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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An experiment was conducted to evaluate different commercial laying hen diets formulated based on recommendations for total and digestible amino acids. One hundred and twenty Lohmann LSL commercial laying hens aged 25 weeks were distributed in a completely randomized experimental design involving five replications of six birds in four treatments. Diet formulation on a total amino acid basis followed the recommendations of NRC (1994) and Rostagno et al. (2000), whereas formulation on digestible amino acids basis was according to Rostagno et al. (2000) and Degussa (1997) recommendations. The experimental period was divided into five periods of fourteen days. Performance parameters (egg production, feed intake, feed conversion, egg mass) were evaluated for each period, and on the last two days of each period, three eggs per replication were collected to evaluate egg quality parameters (Haugh unit, egg specific gravity, egg weight, eggshell thickness and percentage). Means were compared by orthogonal contrasts. Results on feed intake, egg production, egg mass, feed conversion and egg specific gravity showed that total amino acid recommendations promoted better bird responses than digestible amino acid recommendations.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The considered work presents the procedure for evaluation of the uncertainty related to the calibration of flow measurers and to BS&W. It is about a new method of measurement purposed by the conceptual project of the laboratory LAMP, at Universidade Federal do Rio Grande do Norte, that intends to determine the conventional true value of the BS&W from the total height of the liquid column in the auditor tank, hydrostatic pressure exerted by the liquid column, local gravity, specific mass of the water and the specific mass of the oil, and, to determine the flow, from total height of liquid column and transfer time. The calibration uses a automatized system of monitoration and data acquisition of some necessary largnesses to determine of flow and BS&W, allowing a better trustworthiness of through measurements
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A pesquisa foi realizada com o objetivo de verificar a possibilidade de uso da máquina de pré-limpeza, da máquina de limpeza e classificação (ventiladores e peneiras) e da mesa densimétrica para o beneficiamento de sementes de café e, paralelamente, avaliar seus efeitos na qualidade física do lote. Para essa finalidade, um lote de sementes de café arábica 'Catuaí Amarelo IAC 62' foi submetido ao beneficiamento nesses três equipamentos, em diversas combinações. As frações retidas pelas peneiras 22/64 e 20/64 avos de polegada, na máquina de ventiladores e peneiras, constituíram a maior parte do lote e foram processadas, separadamente, em mesa densimétrica. Foram realizadas avaliações de pureza física, massa de mil sementes, peso hectolítrico, teor de água, tipos de sementes predominantes e integridade do endocarpo. Observou-se que: a) A máquina de pré-limpeza, a máquina de ventiladores e peneiras e a mesa densimétrica foram eficientes para a homogeneização do lote de sementes de café, proporcionando obtenção de melhor qualidade física na seqüência operacional em que foram utilizadas de forma conjugada; b) O uso de peneiras com crivos oblongos e crivos circulares, intercaladas na máquina de ventiladores e peneiras, possibilitou a separação de sementes mocas, de sementes com resíduos de exocarpo aderidos ao endocarpo e de sementes desprovidas de endocarpo, melhorando a aparência do lote; c) A mesa densimétrica foi o equipamento que proporcionou melhor separação de sementes com endocarpo danificado, bem como alterações favoráveis à qualidade física do lote; d) As sementes pequenas, retidas nas menores peneiras da máquina de ventiladores e peneiras, e as sementes de menor massa específica, classificadas ou não por tamanho e coletadas na descarga inferior da mesa densimétrica, foram as de baixa qualidade física.
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Considerando-se a escassez de informações sobre o beneficiamento mecanizado de sementes de café, realizou-se este trabalho para estudar seus efeitos na qualidade fisiológica das sementes de café arábica. Um lote de sementes de 'Catuaí Amarelo IAC 62' foi submetido à ação de máquina de pré-limpeza, máquina de ventiladores e peneiras e mesa densimétrica, em diversas combinações, e as sementes foram avaliadas quanto à germinação e ao vigor (envelhecimento acelerado, emergência de plântulas, altura e massa de matéria seca de plântulas e mudas). O teor de água das sementes também foi determinado. Utilizou-se o delineamento estatístico de blocos ao acaso, com quatro repetições, e o teste de Tukey a 5% para comparação de médias. Concluiu-se que: a) a qualidade fisiológica das sementes foi aprimorada à medida que o lote passou por equipamentos específicos no beneficiamento, culminando com a melhor qualidade na seqüência operacional em que o lote foi submetido à ação da máquina de ventiladores e peneiras e mesa densimétrica; b) a mesa densimétrica, associada à máquina de ventiladores e peneiras, foi o equipamento que proporcionou a melhor separação de materiais que interferem negativamente na qualidade fisiológica das sementes; c) as sementes maiores e/ou mais pesadas tiveram qualidade fisiológica superior, e as sementes mocas graúdas, qualidade fisiológica similar à das sementes chatas graúdas; d) o descarte das frações do lote constituídas por sementes pequenas ou de menor densidade possibilitou a obtenção de lotes homogêneos e com alta qualidade fisiológica, favorecendo a obtenção de mudas mais vigorosas.
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The composition of petroleum may change from well to well and its resulting characteristics influence significantly the refine products. Therefore, it is important to characterize the oil in order to know its properties and send it adequately for processing. Since petroleum is a multicomponent mixture, the use of synthetic mixtures that are representative of oil fractions provides a better understand of the real mixture behavior. One way for characterization is usually obtained through correlation of physico-chemical properties of easy measurement, such as density, specific gravity, viscosity, and refractive index. In this work new measurements were obtained for density, specific gravity, viscosity, and refractive index of the following binary mixtures: n-heptane + hexadecane, cyclohexane + hexadecane, and benzene + hexadecane. These measurements were accomplished at low pressure and temperatures in the range 288.15 K to 310.95 K. These data were applied in the development of a new method of oil characterization. Furthermore, a series of measurements of density at high pressure and temperature of the binary mixture cyclohexane + n-hexadecane were performed. The ranges of pressure and temperature were 6.895 to 62.053 MPa and 318.15 to 413.15 K, respectively. Based on these experimental data of compressed liquid mixtures, a thermodynamic modeling was proposed using the Peng-Robinson equation of state (EOS). The EOS was modified with scaling of volume and a relatively reduced number of parameters were employed. The results were satisfactory demonstrating accuracy not only for density data, but also for isobaric thermal expansion and isothermal compressibility coefficients. This thesis aims to contribute in a scientific manner to the technological problem of refining heavy fractions of oil. This problem was treated in two steps, i.e., characterization and search of the processes that can produce streams with economical interest, such as solvent extraction at high pressure and temperature. In order to determine phase equilibrium data in these conditions, conceptual projects of two new experimental apparatus were developed. These devices consist of cells of variable volume together with a analytical static device. Therefore, this thesis contributed with the subject of characterization of hydrocarbons mixtures and with development of equilibrium cells operating at high pressure and temperature. These contributions are focused on the technological problem of refining heavy oil fractions
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Steam assisted gravity drainage process (SAGD) involves two parallel horizontal wells located in a same vertical plane, where the top well is used as steam injector and the bottom well as producer. The dominant force in this process is gravitational. This improved oil recovery method has been demonstrated to be economically viable in commercial projects of oil recovery for heavy and extra heavy oil, but it is not yet implemented in Brazil. The study of this technology in reservoirs with characteristics of regional basins is necessary in order to analyze if this process can be used, minimizing the steam rate demand and improving the process profitability. In this study, a homogeneous reservoir was modeled with characteristics of Brazilian Northeast reservoirs. Simulations were accomplished with STARS , a commercial software from Computer Modelling Group, which is used to simulate improved oil recovery process in oil reservoirs. In this work, a steam optimization was accomplished in reservoirs with different physical characteristics and in different cases, through a technical-economic analysis. It was also studied a semi-continuous steam injection or with injection stops. Results showed that it is possible to use a simplified equation of the net present value, which incorporates earnings and expenses on oil production and expenses in steam requirement, in order to optimize steam rate and obtaining a higher net present value in the process. It was observed that SAGD process can be or not profitable depending on reservoirs characteristics. It was also obtained that steam demand can still be reduced injecting in a non continuous form, alternating steam injection with stops at several time intervals. The optimization of these intervals allowed to minimize heat losses and to improve oil recovery
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In the Einstein s theory of General Relativity the field equations relate the geometry of space-time with the content of matter and energy, sources of the gravitational field. This content is described by a second order tensor, known as energy-momentum tensor. On the other hand, the energy-momentum tensors that have physical meaning are not specified by this theory. In the 700s, Hawking and Ellis set a couple of conditions, considered feasible from a physical point of view, in order to limit the arbitrariness of these tensors. These conditions, which became known as Hawking-Ellis energy conditions, play important roles in the gravitation scenario. They are widely used as powerful tools for analysis; from the demonstration of important theorems concerning to the behavior of gravitational fields and geometries associated, the gravity quantum behavior, to the analysis of cosmological models. In this dissertation we present a rigorous deduction of the several energy conditions currently in vogue in the scientific literature, such as: the Null Energy Condition (NEC), Weak Energy Condition (WEC), the Strong Energy Condition (SEC), the Dominant Energy Condition (DEC) and Null Dominant Energy Condition (NDEC). Bearing in mind the most trivial applications in Cosmology and Gravitation, the deductions were initially made for an energy-momentum tensor of a generalized perfect fluid and then extended to scalar fields with minimal and non-minimal coupling to the gravitational field. We also present a study about the possible violations of some of these energy conditions. Aiming the study of the single nature of some exact solutions of Einstein s General Relativity, in 1955 the Indian physicist Raychaudhuri derived an equation that is today considered fundamental to the study of the gravitational attraction of matter, which became known as the Raychaudhuri equation. This famous equation is fundamental for to understanding of gravitational attraction in Astrophysics and Cosmology and for the comprehension of the singularity theorems, such as, the Hawking and Penrose theorem about the singularity of the gravitational collapse. In this dissertation we derive the Raychaudhuri equation, the Frobenius theorem and the Focusing theorem for congruences time-like and null congruences of a pseudo-riemannian manifold. We discuss the geometric and physical meaning of this equation, its connections with the energy conditions, and some of its several aplications.
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We investigate the cosmology of the vacuum energy decaying into cold dark matter according to thermodynamics description of Alcaniz & Lima. We apply this model to analyze the evolution of primordial density perturbations in the matter that gave rise to the first generation of structures bounded by gravity in the Universe, called Population III Objects. The analysis of the dynamics of those systems will involve the calculation of a differential equation system governing the evolution of perturbations to the case of two coupled fluids (dark matter and baryonic matter), modeled with a Top-Hat profile based in the perturbation of the hydrodynamics equations, an efficient analytical tool to study the properties of dark energy models such as the behavior of the linear growth factor and the linear growth index, physical quantities closely related to the fields of peculiar velocities at any time, for different models of dark energy. The properties and the dynamics of current Universe are analyzed through the exact analytical form of the linear growth factor of density fluctuations, taking into account the influence of several physical cooling mechanisms acting on the density fluctuations of the baryonic component of matter during the evolution of the clouds of matter, studied from the primordial hydrogen recombination. This study is naturally extended to more general models of dark energy with constant equation of state parameter in a flat Universe
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Given the significant share of food costs of poultry production, it is necessary to use strategies and techniques to maximize the utilization and biological value of the components of the diets, keeping constant or improving animal performance. In this context, seeking partial substitution of corn and the best use of the constituents of the diet, the present study aimed to evaluate the effects of inclusion of cashew pomace dehydrated (BCD) and enzyme complex (EC) in the diet on performance and quality eggs of Japanese quails. A total of 200 Japanese quail at 87 days of age, in 25 cages in a completely randomized design in a factorial 2 x 2 + 1 (two levels of cashew bagasse x two levels of enzymes) + control diet without cashew bagasse totaling five treatments with five replicates of eight birds each repetition. The experiment lasted 84 days, divided into four periods of 21 days. The treatments consisted of T1-Ration Control, T2-ration with 7.5% without EC BCD, T3-ration with 7.5% BCD with CE, T4-Ration with 15% BCD without EC and T5-Feed with 15% of BCD with EC. The enzyme complex (EC) is used fermentation product of Aspergillus niger, and cashew bagasse was obtained from the juice industry, passed through drying and crushing process for producing the bran. The performance and egg quality of quails, and performance variables: feed intake (FI), feed conversion ratio per dozen eggs (CAKDZ) and egg mass (CAMO), egg production (OP% bird / day), average egg weight (PMO) and egg mass (MO), and variables were egg quality, specific gravity (SG), Haugh unit (HU), yolk index, and the relationships between components eggs (%albumen,% yolk and %shell). Data were analyzed with the Statistical SAEG (2007). The 7.5 and 15% of cashew bagasse, independent of the enzyme complex decreased feed intake and improved the average egg weight. The two levels with the addition of EC showed significant differences for feed conversion by egg mass. The 7.5 with the addition of enzyme complex obtained the lowest average feed conversion per dozen eggs. The inclusion of up to 15% of cashew bagasse dehydrated with or without addition of enzyme complex in the diet of Japanese quails not interfere in the internal and external quality of eggs. The 7.5 and 15% BCD without added enzyme complex gave better means for specific gravity. Under conditions in which the experiment was conducted, it can be stated that the inclusion of up to 15% of cashew bagasse dehydrated with added enzyme complex feeding quail is economically viable, with the level of 7.5% with the addition of complex enzyme presented the best economic indices
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)