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Search Results: 1 - 10 of 190332 matches for " Elton G. Rossini "
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Some Concerns Related to the Idea of Energetic Complementarity and Its Application  [PDF]
Flávio P. Livi, Elton G. Rossini, Alexandre Beluco
Energy and Power Engineering (EPE) , 2017, DOI: 10.4236/epe.2017.99032
Abstract: This letter to the editor presents some notes on energetic complementarity and a growing understanding of its role as a planning tool. This letter looks at the fact that an increasing number of works in recent years on this subject has promoted an increase in its level of importance in the design and operation of energy systems. The main change is the consideration of complementarity no longer as a consequence but as a design parameter. The continental dimension of Brazil, for example, should make it obvious that complementarities should be sought among the various energy resources available.
Main Results of an Energy Audit in a Milk Processing Industry in Taquara, Southern Brazil  [PDF]
Rejane G. Gon?alves, Elton G. Rossini, José de Souza, Alexandre Beluco
Journal of Power and Energy Engineering (JPEE) , 2018, DOI: 10.4236/jpee.2018.61003
Abstract: The industrial energy diagnosis presented in this work occurred in a milk product cooperative, from an analysis of energy consumption in the main milk industrialization and a diagnosis of energy end uses of lighting and cooling systems. Almost all stages of milk industrialization are used hot water and steam generated in the boilers. The largest electricity consumption in this sector is by electric motors followed by cooling needed to maintain the quality of milk products. Because energy costs represent a significant portion of the monthly cost of the company, an analysis of the energy costs of the past two years to check the consumption of active and reactive energy and power demand contracted is performed. This paper presents the main results of an energy audit in a milk processing industry in southern Brazil.
Influence of Time Complementarity on Energy Storage through Batteries in Hydro PV Hybrid Energy System  [PDF]
Frederico A. During Fo, Alexandre Beluco, Elton G. Rossini, José de Souza
Computational Water, Energy, and Environmental Engineering (CWEEE) , 2018, DOI: 10.4236/cweee.2018.73010
Abstract: The notion of energetic complementarity can be a tool for energy resource managers to prioritize energy generation projects based on renewable resources in both interconnected and independent systems. As a tool in decision-making, it is important to know better the influence of energetic complementarity on the performance of hybrid systems especially with regard to energy shortages but also in relation to other parameters. In recent years, hydro PV hybrid systems have become a growing target of researchers and designers for the idea of installing photovoltaic modules on the water surface of reservoirs. Energetic complementarity has three components: time-complementarity, energy-amplitude and amplitude-complementarity. This paper is dedicated to the study of the influence of time-complementarity on the storage of energy through batteries in hydro PV hybrid systems. The method applied is in the literature and suggests the simulation of the system under study with the idealization of energy availabilities, to remove the effects of climatic variations and the characteristic intermittency of renewable resources. Simulations were performed with the well-known software Homer. The results provided the variations of the states of charge of the batteries as a function of different time-complementarities, indicating as expected better performances associated to higher time-complementarities. The results indicated that the cost of energy for a hybrid system with 28 batteries was equal to US$ 0.502 per kWh and that this cost increased as the time complementarity between energy resources moved away from the situation corresponding to full complementarity. The simulations also showed that the maintenance of the zero failure condition supplying the demands of the consumer loads requires that the load be reduced to 52% if the complementarity is reduced from the full complementarity to zero complementarity, with the cost of energy going from US$ 0.502 per kWh to US$ 0.796 per kWh. The results also allow a better understanding of the influence of time complementarity on the performance of hybrid systems.
A Hydro PV Hybrid System for the Laranjeiras Dam (in Southern Brazil) Operating with Storage Capacity in the Water Reservoir  [PDF]
Gabriel Vasco, Jones S. Silva, Fausto A. Canales, Alexandre Beluco, José de Souza, Elton G. Rossini
Smart Grid and Renewable Energy (SGRE) , 2019, DOI: 10.4236/sgre.2019.104006
Abstract: Seasonal variability coupled with the intermittency of renewable energy sources makes reservoir hydroelectric plants an interesting option to consider in hybrid energy systems, especially in cases of dams that have not been completed or have been abandoned and which still have some potential for reuse. The Laranjeiras dam was completed in the 1960s and the original project for hydroelectric power generation was not completed, made impossible by economic changes during the construction years. A recent study proposed the implementation of a hydroelectric photovoltaic hybrid system with lower horsepower to allow the dam to be made useful again. This paper presents the results of the computational simulations with the software Homer, considering the operation of the hydroelectric component (of the proposed hybrid system) with reservoir, playing the role of energy storage device when the production exceeds the demand at a given moment, reducing the loss of energy due to unavailability of demand. The study suggested to implement a hydroelectric power plant with power house at the base of the dam that has a height of 20 m, operating at a minimum flow of 9171 L/s, with reservoir operating as a device for energy storage, operating with a photovoltaic system of 360 kW, and a power limit for the purchase of energy from the grid equal to 200 kW, providing consumer loads up to 40 MWh per day, with cost of energy equal to US$0.021 per kWh and a capital cost of US$3285.617.
A Hydro PV Hybrid System as a New Concept for an Abandoned Dam in Southern Brazil*  [PDF]
Gabriel Vasco, Jones S. Silva, Alexandre Beluco, Elton G. Rossini, José de Souza
Computational Water, Energy, and Environmental Engineering (CWEEE) , 2019, DOI: 10.4236/cweee.2019.82003
Abstract: The search for alternatives to traditional sources of electric energy opens the way for a new market in the world, and for Brazil in particular. Still in its first steps, but with immense potential, the generation of energy from solar irradiation and hydroelectric plants in hybrid systems is an important alternative. On the other hand, single source power systems, when designed to meet a particular demand without fail, lead to low market acceptance due to the availability of resources and low efficiency in performance that rewards high initial investment costs. One solution to balance and optimize energy supply is the use of more than one energy resource when sources can be complementary. Among several possible combinations reported in several studies, the hybrid photovoltaic hydroelectric system is considered to be an optimal and interesting combination. In this context, the present article makes a technical and economic pre-feasibility analysis of a hydroelectric photovoltaic hybrid system, operating photovoltaic panels on floating structures on the water surface to allow the use of the Laranjeiras dam. The study was conducted based on simulations with HOMER. The solution indicated as optimal was the installation of a hybrid energy system, implementing a hydroelectric power plant at the base of the dam, with 1497 kW of installed capacity, operating simultaneously with a set of photovoltaic modules, on the water surface of the dam, with 180 kW of installed capacity, and a power limit for the purchase and sale to the grid equal to 400 kW, to supply the demand of consumer loads up to 40 MWh per day. This combination would result in an initial cost of US$3984.885 per kW and an energy cost of US$0.026 per kWh.
Electric Field Effects on Graphene Materials
Elton J. G. Santos
Physics , 2014,
Abstract: Understanding the effect of electric fields on the physical and chemical properties of two-dimensional (2D) nanostructures is instrumental in the design of novel electronic and optoelectronic devices. Several of those properties are characterized in terms of the dielectric constant which play an important role on capacitance, conductivity, screening, dielectric losses and refractive index. Here we review our recent theoretical studies using density functional calculations including van der Waals interactions on two types of layered materials of similar two-dimensional molecular geometry but remarkably different electronic structures, that is, graphene and molybdenum disulphide (MoS$_2$). We focus on such two-dimensional crystals because of they complementary physical and chemical properties, and the appealing interest to incorporate them in the next generation of electronic and optoelectronic devices. We predict that the effective dielectric constant ($\varepsilon$) of few-layer graphene and MoS$_2$ is tunable by external electric fields ($E_{\rm ext}$). We show that at low fields ($E_{\rm ext}^{}<0.01$ V/\AA) $\varepsilon$ assumes a nearly constant value $\sim$4 for both materials, but increases at higher fields to values that depend on the layer thickness. The thicker the structure the stronger is the modulation of $\varepsilon$ with the electric field. Increasing of the external field perpendicular to the layer surface above a critical value can drive the systems to an unstable state where the layers are weakly coupled and can be easily separated. The observed dependence of $\varepsilon$ on the external field is due to charge polarization driven by the bias, which show several similar characteristics despite of the layer considered.
A Constitui o Imperial de 1824: Uma breve análise dos aspectos sociais, políticos, econ micos jurídicos
Rossana Teresa Curioni Mergulh?o,Bazilio de Alvarenga Coutinho Junior,Elton Fernando Rossini Machado
Araucaria , 2011,
Abstract: Inevitable say that the Brazilian Constitution of 1988 refl ects an existing reality in our nation. Also notorious that its origin brought a not too distantpast, inserted into your body experiences that have brought benefi ts to society are still there. The constitutional development was necessary for Brazil to move forward, and from this perspective, we will study important aspects of theImperial Constitution of 1824, the fi rst constitution in our country soon after the cessation of colonial Brazil, and who translated the strong features of the European elite, where slavery was still existing. The centralization of power at that time answers many questions about the Constitution currently in force, which reveals more freedom with regard to fundamental rights of citizens, existing in its minimum degree in another letter undemocratic. Analysis, therefore, these two moments.
Food Plants Eaten by Amazonian Manatees (Trichechus inunguis, Mammalia : Sirenia)
Colares, Ioni G.;Colares, Elton P.;
Brazilian Archives of Biology and Technology , 2002, DOI: 10.1590/S1516-89132002000100011
Abstract: to determine the feeding habits of the amazonian manatee trichechus inunguis in some central amazonian rivers and lakes, we compared plant epidermis found in the stomach contents and/or faeces of animals with a reference collection of plants present in the studied areas. twenty five samples from digestive tracts of animals found dead and 25 faeces samples found floating were analyzed. from these samples, 24 aquatic macrophytes were identified. the gramineae family was identified in 96% of the samples, paspalum repens and echinochloa polystachya being the most abundant in the samples. the second most frequent family was the pontederiaceae primarily eichhornia crassipes. during the high water period, the animals showed a more selective diet (eight identified species). in the low water period, when food was more scarce, the animals showed a larger diversity of species in their diet (21 species of plants). differences in the diet among the two studied areas reflected the physiographics characteristics of the region. amazonian manatees fed mostly on emergent plants.
Food Plants Eaten by Amazonian Manatees (Trichechus inunguis, Mammalia : Sirenia)
Colares Ioni G.,Colares Elton P.
Brazilian Archives of Biology and Technology , 2002,
Abstract: To determine the feeding habits of the Amazonian manatee Trichechus inunguis in some Central Amazonian rivers and lakes, we compared plant epidermis found in the stomach contents and/or faeces of animals with a reference collection of plants present in the studied areas. Twenty five samples from digestive tracts of animals found dead and 25 faeces samples found floating were analyzed. From these samples, 24 aquatic macrophytes were identified. The Gramineae family was identified in 96% of the samples, Paspalum repens and Echinochloa polystachya being the most abundant in the samples. The second most frequent family was the Pontederiaceae primarily Eichhornia crassipes. During the high water period, the animals showed a more selective diet (eight identified species). In the low water period, when food was more scarce, the animals showed a larger diversity of species in their diet (21 species of plants). Differences in the diet among the two studied areas reflected the physiographics characteristics of the region. Amazonian manatees fed mostly on emergent plants.
Explicit connection between conformal field theory and 2+1 Chern-Simons theory
D. C. Cabra,G. L. Rossini
Physics , 1995, DOI: 10.1142/S0217732397001722
Abstract: We give explicit field theoretical representations for the observables of 2+1 dimensional Chern-Simons theory in terms of gauge invariant composites of 2D WZW fields. To test our identification we compute some basic Wilson loop correlators reobtaining known results.
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