164 resultados para Energy flow levels
Resumo:
The paper explains the conceptual design of instrumentation that measures electric quantities defined in the trial-use Std. 1459-2000. It is shown how the Instantaneous-Space-Phasor (ISP) approach, based on α, β, 0 components, can be used to monitor electric energy flow, evaluate the utilization of transmission line and quantify the level of harmonic pollution injected by nonlinear loads.
Resumo:
Once defined the relationship between the Starter Motor components and their functions, it is possible to develop a mathematical model capable to predict the Starter behavior during operation. One important aspect is the engagement system behavior. The development of a mathematical tool capable of predicting it is a valuable step in order to reduce the design time, cost and engineering efforts. A mathematical model, represented by differential equations, can be developed using physics laws, evaluating force balance and energy flow through the systems degrees of freedom. Another important physical aspect to be considered in this modeling is the impact conditions (particularly on the pinion and ring-gear contact). This work is a report of those equations application on available mathematical software and the resolution of those equations by Runge-Kutta's numerical integration method, in order to build an accessible engineering tool. Copyright © 2011 SAE International.
Resumo:
Pós-graduação em Agronomia (Energia na Agricultura) - FCA
Resumo:
Pós-graduação em Agronomia (Energia na Agricultura) - FCA
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Currently the world is under an energy revolution, every day more technologies are developed in order to better use the energy for having better energy efficiency of equipment and processes with minimal environmental degradation. Taking into account that thousands of people live in built environments in the context of cities and that the energy flow to this location is significant, it is important to study the built environment as a potential source of savings, energy recovery and regeneration, because cities are the major bottlenecks energetic. Therefore, this study aimed to examine and to list the most important and promising technologies to be used in the built environment to collect or save energy that would be wasted, such as clothes that generate energy through movement or solar incidence, facades of buildings that generate energy due to solar radiation, fitness centers that produce electricity due to the rotation used in fitness equipment for athletes, elevators that take advantage of the potential energy or use it more rationally, generators that take advantage of energy vibrational, and finally more sustainable vehicles with higher performance and less degrading the environment. The information and results obtained from this study show that the technologies used to harness energy before lost are increasingly evident and also is increased the progress relative to the energy use in a urban context. In the closure, a comparison of energy expenditure between a city that uses some of these sustainable technologies and another of the same size with conventional habits is presented
Resumo:
Herbivory is the basal link among the trophic chains and therefore has great importance in the energy flow in the ecosystems. However, the ecological interactions have been changed due to the process of fragmentation that has occurred in the cerrado. Thus, our objective was to evaluate the herbivory and the presence of possible constituents of defense in leaves of Bauhinia rufa in two cerrado fragments of different sizes . We evaluated in both of them species richness and abundance of herbivores as well absolute herbivory ( n = 25 plants / fragment ) . Through histochemical tests and scanning electron microscopy we verified the constituents of defense. The difference between the herbivory in the fragments was not statistically significant ( t = -1.387 , p = 0.166 ) . However , we found a higher abundance of morphotypes of herbivores in the smaller fragment. We detected chemical and physical constituents that may confer protection to the plant at all stages of leaf development. Although several publications have indicated that small fragments have a higher susceptibility to changes, our study revealed no effect of fragment size on the absolute herbivory, suggesting that there are other factors acting more strongly and maintaining this type of interaction in these ecosystems
Resumo:
Based on climatological data and energy flow, this paper analyzes the behavior observed in microclimatic an important remnant of cerrado in the São Paulo State. The seasonal climate is well marked, in the study area, with two climatic periods (one dry and one wet). The vegetation presents physiology as a function of water availability and the local thermal conditions and can be seen marked changes in the landscape due to the more or less presence of solar radiation. It’s important to understand the ecosystems behave in the context of global change. It has gained the attention of many researchers in the world.
Resumo:
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Resumo:
This paper analyzed the energy flow of a route currently designed to transport ethanol from the Midwest region of Brazil for exportation, more precisely from the city of Aparecida do Taboado (MS) to the port of São Sebastiao (SP). The route studied a single modal combined into two pieces, duct - duct. The direct and indirect energy, involved in the operations were used to account for the inputs and outputs of energy from and into the system. The energy input and output were the variables, diesel fuel, lubricants, greases, indirect energy consumption of machinery and equipment, power consumption of labor, the energy consumption and energy consumption in depreciation and maintenance of roads. We found that this route has specific energy consumption of 0,14 MJ km-1 m-3 . The Net Energy Gain (GEl), the Energy Efficiency global (EEg) and Renewable Energy Balance (BEr), which were the energy indicators adopted in this study were obtained respectively: 1.585.958.977,00 MJ; 200,72 and 1.593.900.000,00MJ.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
One hundred sixty-two commercial 70-wk-old ISA Brown laying hens, previously subjected to induced molting by feed restriction, were distributed in a completely randomized design with 3 x 3 factorial arrangement (i.e., 3 metabolizable energy levels: 2,850; 2,950, and 3,050 kcal of ME/kg) and 3 protein levels (16, 18, and 20% CP), which totaled 9 treatments with 3 replicates of 6 birds each. Experimental diets were offered to birds after the feed restriction period. Performance and egg quality parameters were evaluated in 14-d intervals from the 4th to 12th weeks after forced molting for a total of 4 evaluation periods. Increases in dietary energy and protein levels did not improve performance or egg quality. The levels of 2,850 kcal of ME and 16% protein were sufficient for laying hens starting the second production cycle without decreasing their performance or egg quality.
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
Density functional calculation at B3LYP level was employed to study the surface oxygen vacancies and the doping process of Co, Cu and Zn on SnO2 (110) surface models. Large clusters, based on (SnO2)(15) models, were selected to simulate the oxidized (Sn15O30), half-reduced (Sn15O29) and the reduced (Sn15O28) surfaces. The doping process was considered on the reduced surfaces: Sn13Co2O28, Sn13Cu2O28 and Sn13Zn2O28. The results are analyzed and discussed based on a calculation of the energy levels along the bulk band gap region, determined by a projection of the monoelectron level structure on to the atomic basis set and by the density of states. This procedure enables one to distinguish the states coming from the bulk, the oxygen vacancies and the doping process, on passing from an oxidized to a reduced surface, missing bridge oxygen atoms generate electronic levels along the band gap region, associated with 5s/5p of four-/five-fold Sn and 2p of in-plane O centers located on the exposed surface, which is in agreement with previous theoretical and experimental investigations. The formation energy of one and two oxygen vacancies is 3.0 and 3.9 eV, respectively. (C) 2001 Elsevier B.V. B.V. All rights reserved.