963 resultados para heat load index
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The aim of this study was to assess the prevalence of factors associated with oral colonization by Candida spp. in pediatric patients with AIDS. The sample comprised of 117 children. Clinical status, medicines in use, and laboratory findings were obtained from hospital records; sociodemographic data were given by relatives. A dental examination assessed the prevalence of dental caries. The prevalence of oral colonization by Candida was 62%. Only seven children presented clinical manifestation of oral candidosis despite their high viral load index and low-for-age CD4 count. Candida colonization was directly associated with frequent use of antibiotics (prevalence ratio [PR] = 1.44), sulfa drugs (PR = 1.23), alteration in the oral mucosa (PR = 1.55), and untreated dental caries (PR = 1.93). It was inversely associated with the use of antiretroviral therapies (PR = 0.65). Candida albicans was the most frequently detected species (80%); phenotypic tests did not detect C. dubliniensis strains. This study observed a low prevalence of Candida-related oral lesions in these patients, which is compatible with the hypothesis that antiretroviral medicines may have contributed to reducing oral manifestations from Candida infection. The high prevalence of Candida colonization in HIV+/AIDS children with untreated dental caries reinforces the importance of oral health care in interdisciplinary health units that assist these patients.
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Dynamic system test methods for heating systems were developed and applied by the institutes SERC and SP from Sweden, INES from France and SPF from Switzerland already before the MacSheep project started. These test methods followed the same principle: a complete heating system – including heat generators, storage, control etc., is installed on the test rig; the test rig software and hardware simulates and emulates the heat load for space heating and domestic hot water of a single family house, while the unit under test has to act autonomously to cover the heat demand during a representative test cycle. Within the work package 2 of the MacSheep project these similar – but different – test methods were harmonized and improved. The work undertaken includes: • Harmonization of the physical boundaries of the unit under test. • Harmonization of the boundary conditions of climate and load. • Definition of an approach to reach identical space heat load in combination with an autonomous control of the space heat distribution by the unit under test. • Derivation and validation of new six day and a twelve day test profiles for direct extrapolation of test results. The new harmonized test method combines the advantages of the different methods that existed before the MacSheep project. The new method is a benchmark test, which means that the load for space heating and domestic hot water preparation will be identical for all tested systems, and that the result is representative for the performance of the system over a whole year. Thus, no modelling and simulation of the tested system is needed in order to obtain the benchmark results for a yearly cycle. The method is thus also applicable to products for which simulation models are not available yet. Some of the advantages of the new whole system test method and performance rating compared to the testing and energy rating of single components are: • Interaction between the different components of a heating system, e.g. storage, solar collector circuit, heat pump, control, etc. are included and evaluated in this test. • Dynamic effects are included and influence the result just as they influence the annual performance in the field. • Heat losses are influencing the results in a more realistic way, since they are evaluated under "real installed" and representative part-load conditions rather than under single component steady state conditions. The described method is also suited for the development process of new systems, where it replaces time-consuming and costly field testing with the advantage of a higher accuracy of the measured data (compared to the typically used measurement equipment in field tests) and identical, thus comparable boundary conditions. Thus, the method can be used for system optimization in the test bench under realistic operative conditions, i.e. under relevant operating environment in the lab. This report describes the physical boundaries of the tested systems, as well as the test procedures and the requirements for both the unit under test and the test facility. The new six day and twelve day test profiles are also described as are the validation results.
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This work presents an optimization technique based on structural topology optimization methods, TOM, designed to solve problems of thermoelasticity 3D. The presented approach is based on the adjoint method of sensitivity analysis unified design and is intended to loosely coupled thermomechanical problems. The technique makes use of analytical expressions of sensitivities, enabling a reduction in the computational cost through the use of a coupled field adjoint equation, defined in terms the of temperature and displacement fields. The TOM used is based on the material aproach. Thus, to make the domain is composed of a continuous distribution of material, enabling the use of classical models in nonlinear programming optimization problem, the microstructure is considered as a porous medium and its constitutive equation is a function only of the homogenized relative density of the material. In this approach, the actual properties of materials with intermediate densities are penalized based on an artificial microstructure model based on the SIMP (Solid Isotropic Material with Penalty). To circumvent problems chessboard and reduce dependence on layout in relation to the final optimal initial mesh, caused by problems of numerical instability, restrictions on components of the gradient of relative densities were applied. The optimization problem is solved by applying the augmented Lagrangian method, the solution being obtained by applying the finite element method of Galerkin, the process of approximation using the finite element Tetra4. This element has the ability to interpolate both the relative density and the displacement components and temperature. As for the definition of the problem, the heat load is assumed in steady state, i.e., the effects of conduction and convection of heat does not vary with time. The mechanical load is assumed static and distributed
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This paper deals with the effects of hair coat characteristics on the sweating rate of Brazilian Braford cows and estimation of heritabilities and genetic correlations of these traits. Data (n=1607) on hair length, coat thickness, hair diameter, number of hairs per unit area, coat reflectance and sweating rate were recorded from heifers and cows of a commercial herd managed on range under extensive system. The data were analyzed considering the following effects on the model for hair coat traits: classes of sires and contemporary groups; linear effects of month and genotype; linear and quadratic effects of age. The effect of sire was important (P<0.05) for all hair coat traits, except for number of hairs; contemporary groups affected (P<0.05) all hair coat traits; the effect of sampling month was important (P<0.05) for hair length and reflectance; genotype affected (P<0.05) hair length, diameter and coat reflectance; the quadratic effect of age was important (P<0.05) only for coat reflectance. Two models were used to analyze the sweating rate. The first model considered the following fixed effects: classes of contemporary groups and sires; linear effect of genotype, coat thickness, hair length, hair diameter, number of hairs, coat reflectance; linear and quadratic effects of time of day, age, air temperature, partial vapour pressure and radiant heat load. The second model used for the sweating rate considered the same fixed effects for the first model, except that the hair coat characteristics were adjusted for important effects used in the models to analyze hair coat traits. All meteorological factors and contemporary groups were important (P<0.05) on variation of sweating rate in both models. The Restricted Maximum. Likelihood (REML) method was used to estimate variance and covariance components under the sire model. Results included heritability estimates in narrow (h(2)) and broad (H) sense for single-trait analyzes: hair thickness (h(2)=0.16; H-2=0.26); hair length (h(2)=0.18; H-2=0.39); number of hairs (h(2)=0.08 +/- 0.07; H-2=0.08 +/- 0.07); hair diameter (h(2)=0.12 +/- 0.07; H-2=0.12 +/- 0.07); coat reflectance (h(2)=0.30; H-2=0.42); and sweating rate (h(2)=0.10 +/- 0.07; H-2=0.10 +/- 0.07). In general, the genetic correlations between the adaptive traits were favorable as for the direction to select for adaptation in tropical environment; however, they presented high standard errors. The results of this study imply that hair coat characteristics and sweating ability are important for the adaptability to heat stress and they must be better studied and further considered for selection for genetic progress of adaptation in tropical environment. (C) 2007 Elsevier B.V All rights reserved.
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Evaporation is the most effective way of thermolysis with high environmentmal heat load. This mechanism does not depend on the thermal gradient between the environment and animals. The aim of the present work was thermoregulatory responses, sweating rate (TS), rate frequency (FR) e rectal temperature (TR) of Saanen and Oberhasli goats under tropical environment conditions. The observed averages of responses were: TS= 142.91 ± 4.02 g.m-2h-1; FR= 73.23 ± 1.60 mov.min-1; TR= 39.28 ± 0.02oC.
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The aim of the present work was to study the morphological characteristics of the hair coat, coat thickness (E), hair length (C), number of hair by unit area (N), hair angle to skin (A) and hair diameter (D) of Saanen and Oberhasli goats, measured under the conditions of tropical environment. The observed averages of these traits were: E= 6.04±0.08 mm; C= 33.17±0.24 mm; N= 191.50±4.67 hairs.cm-2; A= the 10.67±0.15 degrees; D= 0.203±0.0013 mm.
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Following the thermodynamic formulation of a multifractal measure that was shown to enable the detection of large fluctuations at an early stage, here we propose a new index which permits us to distinguish events like financial crises in real time. We calculate the partition function from which we can obtain thermodynamic quantities analogous to the free energy and specific heat. The index is defined as the normalized energy variation and it can be used to study the behavior of stochastic time series, such as financial market daily data. Famous financial market crashes-Black Thursday (1929), Black Monday (1987) and the subprime crisis (2008)-are identified with clear and robust results. The method is also applied to the market fluctuations of 2011. From these results it appears as if the apparent crisis of 2011 is of a different nature to the other three. We also show that the analysis has forecasting capabilities. © 2012 Elsevier B.V. All rights reserved.
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Purpose. To verify the effects of resistance training at the electromyographic fatigue threshold (EMGFT) based on one-repetition maximum strength (1RM), heart rate (HR), rate of perceived exertion (PE) and endurance time (EndT). Methods. Nineteen subjects (training group [TG]: n = 10; control group [CG]: n = 9), performed 1-min bicep curl exercises sets at 25%, 30%, 35% and 40% 1RM. Electromyography (biceps brachii and brachiorradialis), HR and PE were registered. Biceps brachii EMGFT was used to create a load index for an eight-week resistance training programme (three sets until exhaustion/session, two sessions/week) for the TG. The CG only attended one session in the first week and another session in the last week of the eight-week training period for EndT measurement. EndT was determined from the number of repetitions of each of the three sets performed in the first and last training sessions. After training, 1RM, EMGFT, EndT, HR and PE at the different bicep curl load intensities were again measured for both groups. Results. Increases in 1RM (5.9%, p < 0.05) and EndT (> 60%, p < 0.001) after training were found. In addition, PE was reduced at all load intensities (p < 0.05), while no changes were found for HR and EMGFT after training. Conclusions. Strength-endurance training based on the EMGFT improved muscular endurance and also, to a lesser extent, muscular strength. Moreover, the reduced levels of physical exertion after training at the same intensity suggest that endurance training exercises may improve comfort while performing strength exercises.
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Pós-graduação em Agronomia (Energia na Agricultura) - FCA
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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This work deals with the thermal load study of a fictitious aircraft as well as scaling, in terms of the airflow and temperature of the air conditioning system, for heating and cooling of the its internal environment, aiming the thermal comfort of occupants. The first part is presented the techniques and methods utilized for modeling different heat exchanges that occur in the aircraft and then allowed to calculate the total heat load and the airflow and temperature necessary to comply with the requirements of the thermal comfort. Techniques to determine the basic parameters, as convection coefficient and global coefficient of heat exchange, are also presented. The work aims to develop a program, using a computational tool, to automate the calculations so that facilitate this study. It also allows to be used for other airplanes just changing parameters and the control variables related to the specific project. Finally the program performs calculations for a fictitious airplane, to analyze its functionality and the influence of parameters involved in the temperature controls. The program allowed analyzing the sensitivity of portions of the thermal load and the corresponding parameters of influence, as well as the scaling of the air conditioning in terms of airflow and temperature. It was considered, despite the simplifications, a good approximation to the actual values and then can be used in development of the other airplanes
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The study and selection of an equipment of air conditioner for any type of environment, should be made without overestimate or undersizing the project. The undersizing does not provide an adequate comfort temperature if the environment is too hot because the air conditioner does not remove all the heat necessary in the environment. But if the project is oversized, energy consumption is higher and there is an unnecessary cost. To prevent these failures is necessary to make a calculation of the thermal load on the environment and choose the equipment that has a higher cooling capacity than the calculated heat load and closer to the calculated heat load. In this graduate work will be chosen an air-conditioned equipment for bus, showing the calculations made for the thermal load for various types of heat gain in this type of vehicle. The thermal load on vehicles is more complicated to calculate than in areas because there are several factors that vary with the movement of the vehicle. It will also explain the compression refrigeration cycle, which is the cooling system used in vehicles because it is weightless, compact and lower cost. From the calculated heat load, it will be chosen an air conditioner that best suits the project and, finally, a brief presentation of the selected equipment will be made
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Eighteen Angus steers exposed to high heat load conditions were used to assess the effectiveness of four spray cooling systems, on reducing the effects of heat load, the impact on microclimate and water usage. The steers were housed in groups of nine in a fully enclosed shed and were exposed to high heat load conditions for four days. The cooling systems used were water applied via a hose, via overhead sprinklers, via sprinklers at leg height and via misters. The water used was approximately 31 oC and contained 3% NaCl. Fans were used to ensure adequate air movement over the cattle. The animal parameters measured were feed intake, respiration rate, panting score and behaviour. Climatic factors were ambient temperature and wet bulb temperature. Ammonia levels were also measured. The hose, overhead sprinklers and misting were successful in reducing heat load on the cattle. The leg wetting system did not work because the dominant cattle blocked access to the sprinklers. The misting system used the most water (5483 L) and the hose the least (845 L). The application of water had minor impacts on wet bulb temperature, but resulted in significant reductions in dry bulb temperatures.
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O objectivo principal deste estudo é tentar identificar as possibilidades de melhoria das interfaces físicas das consolas centrais dos automóveis, e a sua ergonomia e usabilidade enquanto meio de realização de tarefas dentro do veículo, de modo a contribuir para melhorar a experiência e a segurança na condução. Neste estudo é feita uma investigação acerca de algumas das interfaces físicas das consolas centrais, medindo o seu desempenho no que diz respeito à distracção do condutor e facilidade de uso em situações de dupla tarefa. Para isso foi adaptado um simulador de condução, e uma bateria de testes de situações de dupla tarefa foi efectuada, de modo a obter dados de telemetria de condução e de desempenho de cada interface da consola central. Os dados obtidos acerca da trajectória do veículo e da sua comparação com trajectórias de referência e a velocidade média nos sectores de condução, foram comparados com dados de desvio de olhar, e que por sua vez sã o comparados e relacionados com os dados de percepção própria do condutor, obtidos através dos testes subjectivos de auto-percepção NASA - Administração Nacional da Aeronáutica e do Espaço - Raw Task Load Index (NASA RTLX). É esperado que desta análise possam ser encontradas algumas conclusões que deverão indicar oportunidades de melhoria às interfaces das consolas centrais, que possam resultar de uma combinação ou divisão dos sistemas, ou que abram caminho ao desenvolvimento de novas soluções alternativas, ou até à criação de um guia de boas práticas para o futuro design e desenvolvimento de interfaces de consolas centrais para automóveis.