128 resultados para Transporte de massa


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This paper introduces an indirect estimate for the coefficients of distribution, hydrodynamic dispersion and retardation for contaminants commonly encountered in sanitary landfills and their liners, such as Cu2+ and K+; this estimate is based on the relationship between concentration and certain physical characteristics of typical Brazilian soils. The results of previous studies investigating the migration of contaminants were used to develop mathematical expressions from multiple non-linear regressions. Using minimal squares regression, this transport was linked to various combinations of contaminant concentration and both structural and textural characteristics of the porous medium. Various combinations of characteristics and concentrations were investigated, with a mathematical expression obtained for each. The relationship between percentage of clay and the contaminant content proved to be the most closely correlated with actual transport parameters, with coefficients close to one.

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The objective of this research was to evaluate the chemical composition and in vitro dry mass (DM) digestibility of sugar cane with urea, maintained in the shade and sun, at different storage times. The utilized design was the completely randomized in a factorial scheme 6x2, that is, six storage times after the mixing (0; 2; 4; 6; 12 and 24 hours) and two storage location (shade and sun), with three replicates. The sugarcane utilized presented 12 months of development and was disintegrated for application of mixture (nine parts of urea for one of ammonium sulfate) to 1.0kg/100.0kg of fresh sugarcane. The samples taken with 12 hours of storage indicated that was an increase in the content of DM and crude protein (CP) of sugar cane compared to the moment of the mixture (307.6 vs. 294.2g/kg of DM and 115.2 vs. 99.3 g/kg of DM, respectively), and the smaller content of neutral detergent fiber (NDF) was observed around of 12 hours of storage (465.0g/kg of DM). The coefficients of in vitro dry mass digestibility (IVDMD) ranged of 0.558 to 0.612 in the times 0 and 12 hours, respectively. The length of storage changes the chemical composition of sugar cane plus urea. The storage location changes the dry mass content and pH values.

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The experimental unit of measurement is a suitable technique to estimate the average character in evaluation, and experimentation should be well understood and executed, because the precision characterizes the quality of the inferences of the results. This research aimed to analyze the possibility to obtaining the quantity of fruit required for sampling of lychee plants, to determining the average mass of the fruits, with less sampling error. One hundred fruits were collected, in a hectare, in two cropping systems, conventional and organic, being one fruit per plant. From the data of fruit mass was used the Excel® to calculate the average fruit mass and number of fruits samples needed to represent the area of the producer. The results show that to achieve a sampling error of 10% for determining the average mass of fruit, 400 fruits should be collected for organic system and 370 for the conventional, while for 20% sampling error, it is necessary to collect 250 fruits per hectare in organic system and 220 in the conventional.

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The possibilities of using the sperm collected from the epididymis have been widely used because the fertilizing capacity sperm preservation and the possibility of using it for wild cats. But in the process of cryopreservation, some studies show a decrease in the quality of the sperm when left under cooling before frozen for some time. This study aimed to assess the quality of the epididymal sperm obtained from domestic cats after cryopreservation using a diluent based on egg yolk and glycerol (Botu-crio®), comparing the morphofunctional characteristics after cooling for 24 hours in a container of semen transport (Botu-tainer®). We use eight cats submitted to elective orchiectomy, aging from eight months, without racial determination, and good nutritional status. These sperm characteristics were: motility, vigor, concentration, membrane integrity and morphology. It has been found, after statistical analysis, that the container of semen was able to maintain sperm viability, even for 24h. We also observed a significant decrease on all parameters after frozen, consequential, probably to thermal stress that occurs in processing. However, the percentage of membrane integrity after thawing shows good employability of the Botu-crio®, which viability is possible to perform in vitro fertilization, requiring higher ratings.

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In soybean culture water deficit is one of the most limiting factors to the maximum yield obtained. Genotypes identification with drought tolerance capacity is fundamental to solve this problem. The objective in this paper was analyze the physiological quality and physiological and biochemical responses of soybeans cultivars (MG/BR 46 Conquista, UFUS Carajás, UFUS Impacta, UFUS Riqueza and UFUS Xavante) submitted to water stress with PEG 6000 solutions in different levels of osmotic potentials (0; -0,1; -0,2; -0,3 and -0,4 MPa). Physiological quality of cultivars were evaluated by seedling length test and fresh and dry biomass. The biochemical responses were evaluated by detection of indol-acetic acid (IAA), by saccharose content and seedling water transportation. UFUS Riqueza presented the best performance in physiological quality tests, saccharose content, absorption and water absorption velocity in seedling. UFUS Xavante showed the highest IAA's concentration and the greater weight of seedling in water transportation test.

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In this paper, capacitated lot sizing problems in which the classical lot sizing decisions are made considering the transportation costs of the manufactured products were studied. These costs are related to the necessary number of pallets or trucks to pack and/or transport the products from the factory to the warehouse. Three extensions of a mixed integer linear programming model from the literature are considered, representing general cases that are commonly found in companies. These models are tested and evaluated using an optimization package, and a Lagrangian heuristic was developed for one of the extensions proposed.

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Pós-graduação em Aquicultura - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Biometria - IBB

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)