检索结果-南通市图书馆

Energy and Power Engineering 2019年第12期11卷 392-397页

作者： Márcio Belloni thadeu das neves conti IPEN/USP S&atilde o Paulo Brazil

Solar generators are known worldwide as a means of generating clean electricity. However, the existence of battery banks causes alarm in the community by the existence of materials that degrade the environment by discarding them outside the norm. With the publication of Regulatory Standards 482/12 and 687/15, solar generators can be connected to the distribution grid, which serves as a means of accumulating the generated energy. The new changes were seen as an economic possibility, but there are more benefits. This has proved very important to make solar generation greener because it no longer needs large battery banks. This has also been shown to significantly lower the final value of the solar generator, bringing economic benefits. This paper aims to analyze the economic and environmental benefits of battery bank distribution in solar generation.

关键词： Solar Energy Decentralized Generation Battery Banks Renewable Energy

Analysis of Materials for Heat Transport in Tokamaks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Nuclear Science and Technology 2020年第1期10卷 39-46页

作者： Márcio Belloni thadeu das neves conti Institute of Energy and Nuclear Research S&atilde o Paulo Brazil

Every nuclear power reactor, whether of fusion or fission, is essentially a thermal system that generates electricity. In this sense, there are several problems in relation to this heat transport. The model of plasma confinement by magnetic force, in the nuclear fusion (sterellator and tokamak), has only been 20 years and recently some success in the quality of the generated plasma has been achieved. However, due to the large amount of energy coming from the plasma, the choice of the material that will carry the generated energy is quite troublesome, due to the need to handle a very high temperature for the nuclear fission standards. Solutions are explored by the scientific community to transport the energy generated in the case of the primary circuit, after exceeding breakeven temperature and models that are based on the fission reactors of the fourth generation and those currently in operation, to search for solutions regarding the transport of heat generated for the generation of electric energy. Several materials such as pressurized water, sodium, helium and boron have been considered and studied to form the primary heat transfer circuit for the exchanger. A thorough analysis of these materials is necessary. This research looked at some of these materials for heat transport and power generation. Lithium and helium were found to be the probable materials for conveying heat and cooling in the blanket. The results show that research on blanket materials needs more attention. The quality of these materials needs to be improved by material research, with the ODS EUROFER alloy and other research to reduce material erosion by helium nano bubbles. Plasma quality needs to be improved to keep constant and free of impurities when using lithium in liquid form.

关键词： Thermonuclear Fusion Tokamak Renewable Energy ITER Project Material Analysis

Application of the Hierarchical Functions Expansion Method for the Solution of the Two Dimensional Navier-Stokes Equations for Compressible Fluids in High Velocity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and Power Engineering 2017年第2期9卷 86-99页

作者： thadeu das neves conti Eduardo Lobo Lustosa Cabral Gaianê Sabundjian Instituto de Pesquisas Energé ticas e Nucleares (IPEN) S&atilde o Paulo Brazil Escola Polité cnica da Universidade de Sã o Paulo (USP) S&atilde o Paulo Brazil

This work presents a new application for the Hierarchical Function Expansion Method for the solution of the Navier-Stokes equations for compressible fluids in two dimensions and in high velocity. This method is based on the finite elements method using the Petrov-Galerkin formulation, know as SUPG (Streamline Upwind Petrov-Galerkin), applied with the expansion of the variables into hierarchical functions. To test and validate the numerical method proposed as well as the computational program developed simulations are performed for some cases whose theoretical solutions are known. These cases are the following: continuity test, stability and convergence test, temperature step problem, and several oblique shocks. The objective of the last cases is basically to verify the capture of the shock wave by the method developed. The results obtained in the simulations with the proposed method were good both qualitatively and quantitatively when compared with the theoretical solutions. This allows concluding that the objectives of this work are reached.

关键词： Computational Fluid Mechanics Compressible Flow Finite Elements Method Navier-Stokes Equations Shock Waves

Hierarchical Expansion Method in the Solution of the Navier-Stokes Equations for Incompressible Fluids in Laminar Two-Dimensional Flow

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy and Power Engineering 2018年第1期10卷 1-9页

作者： Gaianê Sabundjian thadeu das neves conti Eduardo Lobo Lustosa Cabral Reactor Department Nuclear Energy Research Institutes S&atilde o Paulo Brazil

Among the several methods used to solve the Navier-Stokes equations Hierarchical Expansion Method has demonstrated satisfactory results. This work aimed to apply the expansion of the variables in hierarchical functions for the solution of the Navier-Stokes equations for incompressible fluids in two dimensions in laminar flow. This method is based on the finite element method. The expansion functions in this study were based on Legendre polynomials, adjusted in the rectangular elements in such a way that corner, side and area functions were defined. The order of the expansion functions associated with the sides and with the area of the elements is adjusted to the necessary or desired degree. This method is denominated by Hierarchical Expansion Method. In order to validate the proposed numeric method three well-known problems of the literature in two dimensions were analyzed;however, for this paper only one problem was presented. The results demonstrated that method was able to provide precise results. From the results obtained in this paper it is possible to conclude that the hierarchical expansion method can be effective for the solution of fluid dynamic problems that involve incompressible fluids.

关键词： Finite Element Petrov-Galerkin Formulation Navier-Stokes Equations Hierarchical Expansion Functions Incompressible Fluid

Application of the Hierarchical Functions Expansion Method for the Solution of the Two Dimensional Navier-Stokes Equations for Compressible Fluids in High Velocity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Bitcoin pricing: impact of attractiveness variables

Energy and Power Engineering（能源与动力工程） 2017年第2期

作者： thadeu das neves conti Eduardo Lobo Lustosa Cabral Gaianê Sabundjian

来源：评论

学校读者我要写书评

暂无评论

Financial Innovation 2020年第1期6卷 373-391页

作者： Rodrigo Hakim das neves Sao Paulo School Of Economics(FGV) Sao PauloBrazil

The research seeks to contribute to Bitcoin pricing analysis based on the dynamics between variables of attractiveness and the value of the digital *** the error correction model,the relationship between the price of the virtual currency,Bitcoin,and the number of Google searches that used the terms bitcoin,bitcoin crash and crisis between December 2012 and February 2018 is *** study also applied the same analysis to prices of Bitcoin denominated in different sovereign currencies traded during the same *** Johansen(J Econ Dyn Control 12:231-254,1988)test demonstrates that the price and number of searches on Google for the first two terms are *** research indicates that there are strong short-term and long-term dynamics among attractiveness factors,suggesting that an increase in worldwide interest in Bitcoin is usually preceded by a price *** contrast,an increase in market mistrust over a collapse of the currency,as measured by the term bitcoin crash,is followed by a fall in *** world economic crisis events appear to have a strong impact on interest in the virtual *** study demonstrates that during a worldwide crisis Bitcoin becomes an alternative investment,increasing its *** on it,bitcoin may be used as a safe haven by the financial market and its intrinsic characteristics might help the investors and governments to find new mechanisms to deal with monetary transactions.

关键词： Bitcoin pricing Price variables Crisis

Numerical Solution for a Non-Fickian Diffusion in a Periodic Potential

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2013年第2期13卷 502-525页

作者： Adérito Araújo Amal K.das Cidália neves Ercília Sousa CMUC Department of MathematicsUniversity of Coimbra3001-454 CoimbraPortugal Department of Physics DalhousieUniversityHalifaxNova Scotia B3H3J5Canada ISCAC Polytechnic Institute of Coimbra3040-316 CoimbraPortugal

Numerical solutions of a non-Fickian diffusion equation belonging to a hyperbolic type are presented in one space *** Brownian particle modelled by this diffusion equation is subjected to a symmetric periodic potential whose spatial shape can be varied by a single *** consider a numerical method which consists of applying Laplace transform in time;we then obtain an elliptic diffusion equation which is discretized using a finite difference *** analyze some aspects of the convergence of the *** results for particle density,flux and mean-square-displacement(covering both inertial and diffusive regimes)are presented.

关键词： Numerical methods Laplace transform telegraph equation periodic potential non-Fickian diffusion

Analysis of foundation sliding of an arch dam considering the hydromechanical behavior

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2012年第1期6卷 35-43页

作者： Maria Luísa Braga FARINHA JoséVieira de LEMOS Emanuel MARANHA das neves LNEC-National Laboratory for Civil Engineering Av.Brasil 101Lisboa 1700-066Portugal IST-Instituto Superior Técnico Av.Rovisco Pais 1Lisboa 1049-001Portugal

This paper presents the application of a methodology which can be used to assess arch dam foundation stability,using the discrete element method(DEM)and the code 3DEC.A global three-dimensional model of a dam foundation was developed,in which some discontinuities were simulated and both the grout and drainage curtains were *** model,calibrated taking into account recorded data,was used to carry out nonlinear mechanical *** same model was employed to perform a hydraulic analysis,based on equivalent continuum concepts,which allowed the water pressure pattern within the foundation to be *** water pressures were applied on discontinuities involved in the possible sliding mechanism along the dam/foundation interface,and the safety of the dam/foundation system was evaluated using a process of reduction of strength characteristics,with the aim of calculating the minimum safety factors that ensure *** were compared with those obtained with the usual bi-linear uplift pressure distribution at the base of the dam,commonly used in concrete dam *** relevance of carrying out hydraulic analysis in arch dam foundation failure studies is highlighted.

关键词： concrete dams rock foundations hydromechanical behavior failure analysis

Atlas of precipitation extremes for South America and Africa based on depth-duration-frequency relationships in a stochastic weather generator dataset

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Soil and Water Conservation Research 2023年第4期11卷 726-742页

作者： Andrew Fullhart David C.Goodrich Menberu B.Meles Paulo Tarso S.Oliveira Cristiano das neves Almeida JoséC.de Araújo Shea Burns Southwest Watershed Research Center USDA-ARS 2000 E.Allen Rd.TucsonAZ85719United States Sustainable Agricultural Water Systems Unit USDA-ARS 239 Hopkins RoadDavisCA95616United States Faculty of Engineering Architecture and Urbanism and GeographyUniversidade Federal de Mato Grosso do SulCampo GrandeMS79070-900Brazil Water Resources and Environmental Engineering Laboratory Universidade Federal da ParaíbaJoao PessoaPB58051-900Brazil Department of Agricultural Engineering Campus do Pici Fortaleza Universidade Federal do CearáFortaleza60020-181Brazil

Information about extreme rainfall is lacking in regions of South America and *** study attempts to fill this scientific gap by use of a gridded parameterization for the stochastic weather generator,CLIGEN,to map depth-duration-frequency(DDF)*** of 500-year point-scale precipitation time series generated at each grid point allowed maps of return period precipitation to be produced for a se-lection of sixteen durations ranging from 10-min to 1-year and for nine return periods from 2 to 500 *** generalized extreme value(GEV)probability distribution was fitted for all durations,and given GEV quantiles,an interpolation method was applied to produce maps at 0.1° resolution that better resolve small-scale spatial climate *** addition to uncertainties related to GEV fitting,this study quantifies prediction intervals based on ground *** validation was important for identifying biases in CLIGEN,although uncertainties were not always satisfactorily defined due to sampling design and other *** daily/multi-day durations,100 stations with daily observations and ≥50-year records were selected for validation against the 0.1° CLIGEN map series,resulting in a median and average absolute error of 13%and 16%,*** sub-daily durations,prediction errors were larger *** analogy using available *** established the degree of bias in CUGEN for sub-daily durations,and three records in Brazil with high temporal resolutions were used to confirm that applied bias adjustments resulted in error ranges similar to the daily/multi-day *** atlas is freely available for study of extreme precipitation.

关键词： Africa Depth-duration-frequency Extreme precipitation South America

Surface runoff and soil erosion in a natural regeneration area of the Brazilian Cerrado

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Soil and Water Conservation Research 2020年第2期8卷 124-130页

作者： Karina dos Santos Falcao Elói Panachuki Felipe das neves Monteiro Roniedison da Silva Menezes Dulce B.B.Rodrigues Jullian Souza Sone Paulo Tarso S.Oliveira Department of Agronomy State University of Mato Grosso do SulAgronomy DepartmentAquidauanaMS79200-000Brazil Federal University of Mato Grosso do Sul CxP 549Campo GrandeMS79070-900Brazil Department of Hydraulics and Sanitation Sao Carlos School of EngineeringUniversity of Sao PauloCxP.359Sao CarlosSP13566-590Brazil

The Brazilian Cerrado has been converted to farmland,and there is little evidence that this expansion will decrease,mainly because agriculture is the country's main economic ***,the impacts of intense modification of land use and land cover on surface runoff and soil erosion are still poorly un-derstood in this ***,we assessed surface runoff and soil loss in a woodland Cerrado area under a former pasture area,which was abandoned and has undergone a natural regeneration process for 7 years(RC).Its results were compared with that found in an undisturbed area of woodland Cerrado(CE),40-month-old eucalyptus(3.0×1.8 m)(EU),and pasture under rotational grazing(PA).The study was conducted on Red Acrisol located in the Brazilian *** performed rainfall simulations on a plot of 0.7 m2 and using three constant rainfall intensities of 60,90,and 120 mm h-1 for 1 *** each rainfall intensity,we carried out four repetitions using different plots in each treatment,i.e.12 plots per treat-ment studied and 48 plots in *** noted that the soil physical properties were improved in RC and,consequently,water infiltration and soil erosion control;RC presented surface runoff and soil loss different from EU and PA(a=0.05).The macroporosity and soil bulk density affected surface runoff in RC and PA because the RC was used as pasture and is currently regenerating back to the cerrado *** the rainfall intensity increased,EU became more similar to PA,which showed the highest surface runoff and soil *** findings indicate that natural regeneration processes(pasture to the cerrado vegetation)tend to improve the soil ecosystem services,improving infiltration and reducing surface runoff and soil erosion.

关键词： Cerrado deforestation Forest regeneration Soil erosion