84 results
Search Results
52. INTRODUCING A CAUSAL PAR( p ) MODEL TO EVALUATE THE INFLUENCE OF CLIMATE VARIABLES IN RESERVOIR INFLOWS: A BRAZILIAN CASE
- Author
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Pedro Guilherme Costa Ferreira, Reinaldo Castro Souza, Fernando Luiz Cyrino Oliveira, Paula Medina Maçaira, and Fernanda Villa Nova de Almeida
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business.industry ,lcsh:Mathematics ,Climate predictors ,0208 environmental biotechnology ,Climatic variables ,02 engineering and technology ,Inflow ,Management Science and Operations Research ,Power sector ,lcsh:QA1-939 ,Periodic models ,01 natural sciences ,020801 environmental engineering ,Nameplate capacity ,010104 statistics & probability ,Reservoir inflow modelling ,Econometrics ,Environmental science ,Operations management ,Electricity ,0101 mathematics ,business ,Energy matrix - Abstract
The Brazilian electricity energy matrix is essentially formed by hydraulic sources which currently account for 70% of the installed capacity. One of the most important characteristics of a generation system with hydro predominance is the strong dependence on the inflow regimes. Nowadays, the Brazilian power sector uses the PAR(p) model to generate scenarios for hydrological inflows. This approach does not consider any exogenous information that may affect hydrological regimes. The main objective of this paper is to infer on the influence of climatic events in water inflows as a way to improve the model’s performance. The proposed model is called “causal PAR(p)” and considers exogenous variables, such as El Niño and Sunspots, to generate scenarios for some Brazilian reservoirs. The result shows that the error measures decrease approximately 3%. This improvement indicates that the inclusion of climate variables to model and simulate the inflows time series is a valid exercise and should be taken into consideration.
- Published
- 2017
53. Construction of a Chilean energy matrix portraying energy source substitution:A system dynamics approach
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Carla Rúa Gómez, Santiago Arango-Aramburo, and Erik R. Larsen
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Consumption (economics) ,Engineering ,021103 operations research ,Renewable Energy, Sustainability and the Environment ,business.industry ,Strategy and Management ,Fossil fuel ,0211 other engineering and technologies ,02 engineering and technology ,Energy planning ,Environmental economics ,Chilean energy sector ,System dynamics ,Industrial and Manufacturing Engineering ,Energy accounting ,Energy policy ,Renewable energy ,Energy matrix ,Economy ,Production (economics) ,021108 energy ,business ,Energy source ,General Environmental Science - Abstract
The energy matrix is a useful tool for understanding the trends of production and consumption in a country and for evaluating long-term energy policies. This paper presents a behavioral simulation model of the evolution of Chile’s energy matrix. The model is developed and calibrated by considering a dynamic substitution of energy sources. Chile’s stated policy is to become less dependent on imported fossil fuels, to increase security of supply and improve the environment. The simulation experiments show that the energy matrix is very robust with regards to external fuel prices and changes in investment cost. Thus, in order to be able to observe changes in the composition of the energy matrix, there is a need for strong intervention by the regulator, or the government, to provide incentives for renewables.
- Published
- 2017
54. Nicaragua's 2013 residential lighting program: Prospective assessment
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Ildo Luís Sauer, Sônia Seger Pereira Mercedes, and Carlos Germán Meza
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Incandescent light bulb ,Engineering ,business.industry ,Management, Monitoring, Policy and Law ,Environmental economics ,Residential sector ,law.invention ,General Energy ,Benefit analysis ,law ,Order (exchange) ,Pilot program ,Christian ministry ,Operations management ,business ,Energy matrix ,Efficient energy use - Abstract
The Ministry of Energy and Mines of Nicaragua (MEM) is planning to launch in 2013 a massive replacement program of 2 million incandescent lamps with compact fluorescent lamps (CFLs). This paper explores the expected impacts on a 10 year basis (2013–2023) using cost/benefit analysis for consumers, utility and society. Market conditions for introduction of a 7 W LED in the residential sector were also analyzed. Three prospective scenarios were considered in order to estimate the impact of CFLs penetration. Finally, the analysis is complemented with laboratory tests for eight lamps—three CFLs of the pilot program batch and one incandescent lamp 75 W; three CFLs and a 7 W LED available in the national market. Results supports that for countries like Nicaragua with an energy matrix still dependent on imported petroleum, energy efficiency programs are especially positive in economic and environmental terms. However, it is necessary to implement and to test CFLs programs requirements about high power factor (PF≥0.9) and low total harmonic distortion (THD≤20%).
- Published
- 2014
55. Grid Connected Photovoltaic Systems to the Urban Environment of Argentinian Northeast
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Arturo Busso, Manuel O. Cáceres, and Luis Horacio Vera
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Engineering ,distributed generation ,business.industry ,Photovoltaic system ,Environmental economics ,Grid ,Civil engineering ,Renewable energy ,grid connected photovoltaic systems ,Electricity generation ,Energy(all) ,Distributed generation ,energy quality ,business ,Low voltage ,Urban environment ,Energy matrix - Abstract
The last 20 years have presented a favorable scenario for the incorporation of renewable energy sources into the energy matrix of developing countries. This situation promoted grid connected photovoltaic generation systems (GCPVS) to become one of the main protagonists in this new concept of energy matrix. In some developing countries the use of such systems is in its beginning. Promotion policies and technical as well as regulatory conditions for their installation have just started to be defined. In this context, there exists in Argentina a legal and regulatory framework for the implementation of large photovoltaic plants but there is a lack of such legal framework for distributed generation (DG) by means of grid connected photovoltaic into the medium and low voltage distribution networks. This situation led research centers, together with private and provincial Energy Agencies to install pilot systems in order to identify and characterize their impact on the low voltage distribution network, taking into account the local grid capacity and characteristics of each province. In this paper the implications of different degrees of penetration of solar photovoltaic power generation evaluated using technical parameters of the network is presented. A set of examples of residential users connected to a distribution substation in the city of Corrientes is analyzed by means of a simulation using real grid data with the incorporation of GCPVS generation. The simulation results show that both the level of penetration of GCPVS systems as well as location where these distributed energy sources should couple to the distribution grid must be carefully assessed to maximize the benefits of the inclusion of distributed generation in urban environments.
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- 2014
- Full Text
- View/download PDF
56. Microgrids Views from a Geographic Information System
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María Rodríguez Gámez, W. Manuel Saltos Arauz, Antonio Vázquez Pérez, and Miguel Castro Fernández
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Engineering ,Geographic information system ,business.industry ,05 social sciences ,Environmental resource management ,Environmental economics ,Management tool ,Medium term ,Sustainable energy ,Renewable energy ,0502 economics and business ,Technical university ,050211 marketing ,business ,Spatial analysis ,050203 business & management ,Energy matrix - Abstract
Currently Ecuador advocates a change in the energy matrix, academic centers should develop a strategy that allows them to short and medium term training specialists give technical responses to this proposal it must create the conditions in college so that future generations be able to link the processes of investment in energy with the territorial space. The Technical University of Manabi (UTM) has proposed a research project funded by the National Secretary of Planning and Development of Ecuador (Senplades), aimed at boosting sustainable energy solutions that are based on the technical philosophy of microgrids with the use of renewable energy sources (RES). In this paper the spatial information related to solar energy potential of the province of Manabi, Ecuador's, managed by a geographic information system (GIS ) as an integration tool that provides information on objectives that interact with microgrids shown, also the importance of its use as a management tool projects related to the use of RES and instrumentation aimed at ensuring innovative solutions to support the change of energy matrix from a territorial perspective is exposed.
- Published
- 2016
57. Unified calculation of optical and EPR spectral data for Cr3+-doped KAl(MoO4)2 crystal
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Yang Mei, Ren-Ming Peng, Wen-Chen Zheng, and Cheng-Fu Wei
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Chemistry ,Organic Chemistry ,Doping ,Trigonal crystal system ,Molecular physics ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Ion ,law.invention ,Inorganic Chemistry ,Crystal ,Computational chemistry ,law ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,Spectral data ,Electron paramagnetic resonance ,Spectroscopy ,Visible spectrum ,Energy matrix - Abstract
This paper reports an unified calculation of optical and EPR spectral data for Cr3+ ion at the trigonal Al3+ site of KAl(MoO4)2 crystal from the complete diagonalization (of energy matrix) method based on the two-spin–orbit-parameter model. In this model, differing from that in the conventional crystal-field theory, not only the contributions from the spin–orbit parameter of central dn ion, but also those from the spin–orbit parameter of ligand ion via covalence effect are taken into account. The calculation shows that by using only three adjustable parameters, the observed twelve optical and EPR spectral data (nine optical band positions and three EPR parameters g||, g⊥ and D) are reasonably explained in a unified way with this method. The results are discussed.
- Published
- 2015
58. Defect models of two tetragonal Ce3+ centers T1 and T2 in Ce3+-doped cubic fluorperovskites KMgF3 and BaLiF3
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Yu-Guang Yang, Wen-Chen Zheng, Hong-Gang Liu, and Yang Mei
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Condensed matter physics ,Chemistry ,Mechanical Engineering ,Doping ,Metals and Alloys ,Crystallographic defect ,Molecular physics ,law.invention ,Tetragonal crystal system ,Mechanics of Materials ,law ,Vacancy defect ,Excited state ,Materials Chemistry ,Electron paramagnetic resonance ,Multiplet ,Energy matrix - Abstract
The EPR g factors g|| and g⊥ for two tetragonal Ce3+ centers T1 and T2 in Ce3+-doped cubic fluorperovskites KMgF3 and BaLiF3 are calculated from the complete diagonalization (of energy matrix) method (where all the Kramers doublets within the ground and excited multiplets 2F5/2 and 2F7/2 are contained). The calculations show that the simple method of calculating g factors (where only the doublets within the ground multiplet 2F5/2 are considered) used in the previous papers cannot give the correct signs of crystal-field parameter B 2 0 and hence the reasonable defect models for these tetragonal Ce3+ centers (in fact, physically, these defect models are inconsistent). The new and consistent defect models for these Ce3+ centers are suggested as follows: in KMgF3:Ce3+, centers T1 and T2 are the substitution of Ce3+ for K+ with a nearest interstitial F− and, respectively, with and without a nearest K+ vacancy (VK) along C4 axis, and in BaLiF3:Ce3+, centers T1 and T2 are the substitution of Ce3+ for Ba2+ with, respectively, a nearest interstitial F− and a nearest Ba2+ vacancy along C4 axis because of charge compensation. Based on these defect models and by considering the orbit reduction effect due to the covalence of Ce3+–F− bonds, the g factors of these tetragonal centers are explained reasonably. The results (in particular, the approximations of the defect structural data for these tetragonal centers) are discussed.
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- 2013
59. Frontier Configurations and a New Classification of Annulenes
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Epiotis, Nicolaos Demetrios, Berthier, Gaston, editor, Dewar, Michael J. S., editor, Fischer, Hanns, editor, Fukui, Kenichi, editor, Hall, George G., editor, Hartmann, Hermann, editor, Jaffé, Hans H., editor, Jortner, Joshua, editor, Kutzelnigg, Werner, editor, Ruedenberg, Klaus, editor, Scrocco, Eolo, editor, and Epiotis, Nicolaos Demetrios
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- 1983
- Full Text
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60. Hückel Valence Bond Theory of Stereoselection
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Epiotis, N. D., Larson, J. R., Eaton, H. L., Berthier, Gaston, editor, Dewar, Michael J. S., editor, Fischer, Hanns, editor, Fukui, Kenichi, editor, Hall, George G., editor, Hartmann, Hermann, editor, Jaffé, Hans H., editor, Jortner, Joshua, editor, Kutzelnigg, Werner, editor, Ruedenberg, Klaus, editor, Scrocco, Eolo, editor, Epiotis, N. D., Larson, J. R., and Eaton, H. L.
- Published
- 1982
- Full Text
- View/download PDF
61. Diversification of Brazilian energy matrix by connecting distributed generation sources fuelled by biogas from swine manure
- Author
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Alexandre Barin, D. Maguerroski, W. S. Brignol, L. N. Canha, and Rodrigo Motta de Azevedo
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Electricity generation ,Biogas ,business.industry ,Distributed generation ,Environmental science ,Agricultural engineering ,AC power ,Diversification (marketing strategy) ,business ,Manure ,Energy matrix ,Renewable energy - Abstract
One way to minimize the problem of energy deficit is to diversify the Brazilian energy matrix, mainly through connecting distributed generation (DG) that uses renewable energy sources — such as biogas from swine manure. This paper aims to estimate the energy potential of power generation from biogas derived from swine manure for a particular study case, also analyzing the impact of DG connection in a distribution network.
- Published
- 2016
62. Modeling of crystal field and spin-Hamiltonian parameters for Ti3+:MgO
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A.S. Gruia, C.N. Avram, and A.M. Barb
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Physics ,Ab initio ,Spin hamiltonian ,Condensed Matter Physics ,Molecular physics ,Electronic, Optical and Magnetic Materials ,law.invention ,symbols.namesake ,Superposition principle ,Nuclear magnetic resonance ,law ,Crystal field theory ,symbols ,Electrical and Electronic Engineering ,Hamiltonian (quantum mechanics) ,Electron paramagnetic resonance ,Hyperfine structure ,Energy matrix - Abstract
The aim of this paper is to model the crystal field parameters (CFPs) and spin-Hamiltonian parameters (g factors g | | , g ⊥ and hyperfine structure constants A | | , A ⊥ ) for the Ti3+:MgO system. The CFPs were modeled in the frame of superposition model of the crystal field theory, based on ab initio supercell calculations of Ti3+:MgO geometry and crystal field parameter 10Dq. The obtained values were used to simulate the energy levels scheme, by diagonalizing the full energy matrix of the Hamiltonian. The EPR parameters have been calculated from both the complete diagonalization method and the perturbation theory method. All the obtained results (optical and EPR) were compared with experimental data and a good agreement is observed.
- Published
- 2013
63. Investigations of the electron paramagnetic resonance parameters and the tetragonal local structure for (VCl 6 ) 4− coordination complex in MCl:V 2+ (M = Na, K, Rb) systems
- Author
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Lin Qi, Rui-Peng Chai, Cai-Xia Zhang, Mei-Ling Duan, and Xiao-Yu Kuang
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chemistry.chemical_classification ,Materials science ,Analytical chemistry ,General Physics and Astronomy ,Crystal structure ,Local structure ,Ion ,Coordination complex ,law.invention ,Tetragonal crystal system ,Nuclear magnetic resonance ,chemistry ,law ,Electron paramagnetic resonance ,Ground state ,Energy matrix - Abstract
By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120x120 complete energy matrix, this paper determines the local lattice structure parameters R(1) and R(2) for MCl:V(2+) (M=Na, K, Rb) systems at 77 K, 195 K and RT (room temperature 295 K or 302 K), respectively. The theoretical results indicate that there exists a compressed distortion in MCl:V(2+) systems. Meanwhile, it finds that the structure parameters R(1), R(2) and vertical bar Delta R vertical bar (= R(1) - R(2)) increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. Delta R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed.
- Published
- 2009
64. A node-to-node composite graph and pseudo-Boolean modelling: An unmanned aerial vehicle energy application
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Brian White, G.P. Kladis, Antonios Tsourdos, and John T. Economou
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Composite graph ,Engineering ,Operations research ,business.industry ,Mechanical Engineering ,Distributed computing ,Aerospace Engineering ,Graph theory ,Application areas ,SAFER ,A priori and a posteriori ,Node (circuits) ,business ,Energy (signal processing) ,Energy matrix - Abstract
Unmanned aerial vehicles (UAV) have been gaining momentum in recent years because of their vast application areas in the defence and civilian sectors. Their use can result in future missions to be more effective while also be conducted in a safer manner. UAVs, due to their large operational potential may be required to travel over long distances and prespecified way points thus requiring an effective and efficient decision making mechanism which allow the UAV to start and complete its mission. These missions may start and terminate at different or identical topological locations (or nodes). In the current paper a node-to-node graph theory energy costs modelling method is developed and presented. The modelling method requires as a priori the node-to-node energy costs. Furthermore, several propositions were presented to allow for the energy matrix to be perturbable, thus representing possible atmospheric variations which may occur during the UAVs mission. The UAV is modelled using energy graphs which allow a topological optimum to be obtained via suitable optimization algorithms. The energy costs implicitly contain time, propulsion force, and velocity information thus producing realistic results.
- Published
- 2007
65. Multiscale analysis of flow patterns in the dense‐phase pneumatic conveying of pulverized coal.
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Jin, Yong, Lu, Haifeng, Guo, Xiaolei, and Gong, Xin
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PULVERIZED coal ,PNEUMATIC-tube transportation ,ELECTRICAL capacitance tomography ,WAVELET transforms ,GAS flow - Abstract
Four typical flow patterns in the vertical pipe of the dense‐phase pneumatic conveying of pulverized coal were obtained, namely packed bed flow, plug flow, churn flow and less dense phase flow. The electrical capacitance tomography (ECT) was used for space–time multiscale analysis. Firstly, Daubechies second order wavelet transform and rescaled range analysis(R/S) were applied for the scientific multiscale decompositions. The multiscale frequency range is that the microscale signal is d1–d5 (2.1875, 70.0000) Hz, the mesoscale signal is d6 and d7 (0.5469, 2.1875) Hz and the macroscale signal is d8–d11 (0.0342, 0.5469) Hz. The multiscale ECT signal characteristics of pure gas flow, particle–wall friction, and particle–particle collision were determined by experiments. The multiscale ECT signal energy matrix is proposed, based on the multiscale energy structure characteristics. Control mechanisms and multiscale statistical rules of four typical flow patterns are obtained. This study provides theoretical support for the study of flow pattern transformation of dense‐phase pneumatic conveying. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
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66. Situação atual e perspectivas do biodiesel no Estado do Tocantins
- Author
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Abraham Damian Giraldo Zuniga, Aécio Alves Andrade, Giani Raquel dos Santos Resplandes Gouvêa, Laila Cristina Gonçalves Silva Amaral, Layanne Ferreira Sodré, Thiago Silva Novais, Aroldo Arévalo Pinedo, and Carla Francisa de Sousa Vieira
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Politikwissenschaft ,Produção ,Context (language use) ,Ecology, Environment ,Production ,Sustainability ,familiar Agriculture ,Biofuels ,Ökologie und Umwelt ,spezielle Ressortpolitik ,lcsh:Social Sciences ,Agricultural science ,Regional development ,Political science ,Sustentabilidade ,Ökologie ,ddc:577 ,Biocombustíveis ,lcsh:Science ,Agricultura familiar ,Agribusiness ,Energy matrix ,Ecology ,Special areas of Departmental Policy ,lcsh:H ,Economy ,Biodiesel production ,ddc:320 ,lcsh:Q - Abstract
A produção de biocombustíveis tem sido amplamente debatida no Brasil e no ano de 2014 foi criado o Programa Nacional de Uso e Produção de Biodiesel (PNPB). Este programa busca incentivar uma maior participação de energias renováveis na matriz energética brasileira, com o objetivo de implementar de forma sustentável, técnica, e econômica, a produção e uso do Biodiesel. Além do enfoque na inclusão social e no desenvolvimento regional, via geração de emprego e renda. No panorama nacional, o Estado do Tocantins destaca-se por dispor de uma vasta disponibilidade de terras e apresentar boas perspectivas logísticas devido a implantação de novos modais de transporte. A agricultura familiar é considerada o grande propulsor do agronegócio com, aproximadamente, 45 mil propriedades rurais. Neste contexto, o presente trabalho visa demonstrar os fatores que contribuem com o cenário da produção de biodiesel no Estado do Tocantins.Palavras-chave: Produção; Sustentabilidade; Agricultura familiar; Biocombustíveis.ABSTRACTBiofuel production has been widely debated in Brazil and in 2014 was created the National Program for Production and Use of Biodiesel (NPPB). This program encouraging a greater share of renewable energies in the Brazilian energy matrix, aiming to implement sustainably , technical , and economic , production and use of biodiesel, with a focus on social inclusion and regional development by generating employment and income . On the national scene, the State of Tocantins is distinguished by having a wide availability of land and has good prospects because of logistical deployment of new modes of transportation. Family farming is considered the major driver of agribusiness with approximately 45000 farms. In this context, this paper aims to demonstrate the factors that contribute to the scenario of biodiesel production in the state of Tocantins.Keywords: Production; Sustainability; familiar Agriculture; Biofuels.
- Published
- 2015
67. Defect model and spin-Hamiltonian parameters for the tetragonal Nd3+ center in the tetragonal phase of SrTiO3 crystal
- Author
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Weiqing Yang, Hong-Gang Liu, Ping Su, and Wen-Chen Zheng
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Physics ,Zeeman effect ,Condensed matter physics ,Spin hamiltonian ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,law.invention ,Condensed Matter::Materials Science ,symbols.namesake ,Tetragonal crystal system ,Nuclear magnetic resonance ,law ,Lattice (order) ,Physics::Atomic and Molecular Clusters ,symbols ,Electrical and Electronic Engineering ,Hamiltonian (quantum mechanics) ,Electron paramagnetic resonance ,Hyperfine structure ,Energy matrix - Abstract
The spin-Hamiltonian parameters (g factors g∥, g⊥ and hyperfine structure constants 143A∥, 143A⊥, 145A∥ and 145A⊥) of the tetragonal Nd3+ center in the low-temperature (T≈4.2 K) tetragonal phase of SrTiO3 are calculated from a diagonalization (of energy matrix) method. In the method, the Zeeman and hyperfine interaction terms are attached to the conventional Hamiltonian and a 52×52 energy matrix concerning the ground term 4HJ (J=9/2, 11/2, 13/2, 15/2) is constructed. The Nd3+ center is attributed to Nd3+ occupying the 12-fold coordinated Sr2+ site in SrTiO3. Differing from the defect model assumed in the previous paper that the tetragonal distortion of this Nd3+ center is due to the association of one interstitial oxygen ion at a nearest neighborhood of Nd3+ and the Nd3+ displacement Δz along C4 axis, we suggest that it is due to the distortion of SrTiO3 lattice in the tetragonal phase. The calculated g factors g∥ and g⊥ show good agreement with the experimental values, suggesting that our defect model of Nd3+ center in SrTiO3 is reasonable. The experimental hyperfine structure constants were not reported and so our calculated results remain to be checked by EPR experiment.
- Published
- 2011
68. Desagregação setorial do balanço energético nacional a partir dos dados da matriz insumo-produto: uma avaliação metodológica
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Marco Antonio Montoya, Ricardo Cortez Lopes, and Joaquim José Martins Guilhoto
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Insumo-Produto ,Input-Output ,Energy Matrix ,lcsh:HB71-74 ,Brasil ,lcsh:HC10-1085 ,lcsh:Economics as a science ,Matriz Energética ,General Economics, Econometrics and Finance ,Brazil ,lcsh:Economic history and conditions - Abstract
O artigo propõe e avalia três metodologias para estimar matrizes energéticas nacionais mais desagregadas a partir dos dados da matriz insumo-produto (MIP). Para avaliar os resultados, foram construídas três matrizes insumo-produto híbridas. As análises de correlação e de acuidade dos multiplicadores, índices de ligação setoriais, requerimentos de energia e emissões de CO2 mostraram convergência de resultados nos métodos Base BEN e Base MIP Ajustada. Conclui-se, portanto, que o uso de coeficientes insumo-produto, como ponderadores de expansão do consumo setorial de energia, permite estimar matrizes energéticas consistentes e que são válidas as análises estruturais da economia realizadas com base nelas. This paper proposes and evaluates three methods for estimating more disaggregated national energy matrices from input-output matrix (IPM) data. To evaluate the results three hybrid input-output matrices were built. Correlation and acuity of multipliers analyses, binding sectorial indices, energy requirements and CO2 emissions showed convergence results in BEN Base and Base Adjusted MIP methods.We conclude, therefore, that the use of input-output coefficients as weights for sectorial energy consumption expansion allows to estimate consistent energy matrices and that the structural analyzes of the economy based on them are valid.
- Published
- 2014
69. IMPACT OF A 20%BIODIESEL IN DIESEL BLEND ( B20 ) ON VEHICLES
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Márcia Figueiredo Moreira and Décio Magioli Maia
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Engineering ,Diesel fuel ,Biodiesel ,Time frame ,Chassis dynamometer ,business.industry ,business ,Track (rail transport) ,Engine wear ,Durability ,Automotive engineering ,Energy matrix - Abstract
The use of biodiesel in Brazil was consolidated after 2005, when the Federal Government established a time frame to insert biodiesel in Brazilian energy matrix and so that a 5% biodiesel in diesel blend (B5) has been mandatory since January, 2010. Now the attention turns to blends with higher level of biodiesel and vehicle and engine assemblers, fleet owners and other private and governmental entities are conducting extensive researches on the subject. This paper evaluates the use of a 20% biodiesel in diesel blend (B20) in light duty vehicles with EURO III and EURO IV technologies and its impact on the durability of engines and systems. Vehicles of both technologies endured a field test during which they accumulated 100.000 km in urban and road circuits. They were then evaluated according to the deterioration of performance and pollutants emissions and wear of parts and components. Results were compared to those obtained in similar vehicles using a B5 blend as fuel, subjected to the same test conditions. Engine wear and deposit formation on rings, pistons and cylinders were evaluated by the manufacturers through visual and dimensional inspections, and were found compatible to the use of the engines; there was no significant differences between the groups. Track performance and chassis dynamometer emissions tests showed that EURO IV vehicles were less influenced by the use of differentiated fuels, with vehicles that run on B20 during the field test showing results statistically equivalent to those that run on B5. On the other hand, EURO III vehicles that run on B20 had performance losses up to 7% when compared to those that run on B5. They could not be evaluated according to their emissions.
- Published
- 2014
70. A theoretical study of EPR g factors for the rhombic CuCl64− clusters in (3-chloroanilinium)8[CdCl6]Cl4:Cu2+ crystal
- Author
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Zheng Wen-Chen, Yang Wei-Qing, Zhang Dong-Ting, and He Lv
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Ligand field theory ,Materials science ,Condensed matter physics ,Diagonalizable matrix ,Condensed Matter Physics ,Spectral line ,Electronic, Optical and Magnetic Materials ,law.invention ,Ion ,Crystallography ,law ,Electrical and Electronic Engineering ,Electron paramagnetic resonance ,Ground state ,Energy matrix ,Visible spectrum - Abstract
In this paper, the third-order perturbation formulas of EPR g factors g(i) (i=x, y, z) for d(9) ions in rhombic symmetry where the ground state being an vertical bar d(x2-y2)> admixture of and vertical bar d(z2)> states are derived. These formulas are based on a two-spin-orbit-parameter model in which the contributions to g factors due to both the spin-orbit parameter of the central 3d(n) ion and that of ligand ion are included. From these formulas, the g factors g(i) for the rhombic CuCl(6)(4-) clusters in (3-chloroanilinium)(8)[CdCl(6)]CL(4):Cu(2+) crystal are calculated. The calculated values are in good agreement with those obtained by the complete diagonalization (of energy matrix) method and experimental values. Results are discussed. (C) 2010 Elsevier B.V. All rights reserved.
- Published
- 2010
71. GERAÇÃO DE ENERGIA ELÉTRICA ATRAVÉS DA ENERGIA HIDRÁULICA E SEUS IMPACTOS AMBIENTAIS
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Cristiane Bozzetto, Kariane Lazzare, Patrícia Grassi, Bruna Tartas, Rosemar de Queiroz, Ezequiel Koppe, and Pedro Daniel da Cunha Kemerich
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business.industry ,Energy (esotericism) ,Environmental engineering ,General Medicine ,Investment (macroeconomics) ,Environmental protection ,Action plan ,Environmental science ,Production (economics) ,Electric power ,business ,Hydropower ,Waterlogging (agriculture) ,Energy matrix - Abstract
This paper aimed makes a bibliographic review of how the electric energy is generated by hydropower plants and the environmental injuries by this kind of enterprise. The hydraulic energy is produced through the power of water movement, by hydropower plants. The main factors that influence the generation of this energy are: river’s flow, quantity of available water in a determined period of time and the difference in level, being them naturals, like waterfalls, or created artificially. Although of a significantly portion of contribution in world energy matrix, hydraulic energy causes several socioeconomic impacts, as great areas waterlogging injuring flora, fauna and the community that lives around the river. However this impacts are important whereas can be easily corrected, with a good environmental and social assistance, and a part of the investment coasts destined to it. Before the implantation of this enterprise, it’s important make and action plan aiming reduce
- Published
- 2013
72. Robustness of optimal sensor placement under parametric uncertainty
- Author
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Michael I. Friswell, Rafael Gallego, Rafael Castro-Triguero, and Senthil Murugan
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Mathematical optimization ,Engineering ,business.industry ,Mechanical Engineering ,Modal analysis ,Aerospace Engineering ,Computer Science Applications ,symbols.namesake ,Truss bridge ,Modal ,Control and Systems Engineering ,Robustness (computer science) ,Control theory ,Signal Processing ,symbols ,Fisher information ,business ,Condition number ,Civil and Structural Engineering ,Parametric statistics ,Energy matrix - Abstract
This paper examines the influence of parametric uncertainties on the optimal sensor placement methodologies for the modal analysis of a truss bridge. Four classical sensor location methodologies are employed: two based on the Fisher information matrix and the other two based on energy matrix rank optimization. Young's modulus, mass density and cross sectional dimensions are considered as uncertain parameters. The independent and cumulative effects of these uncertain variables on the sensor placement are studied. The optimal locations of sensors under parametric uncertainty are assessed with three different criteria: the Fisher matrix determinant, the modal assurance criterion error and the condition number. Furthermore, the robustness of this configuration is investigated for the case of random and bias errors. The numerical results show the parametric uncertainties have significant influence on the optimal sensor configuration of a truss bridge.
- Published
- 2013
73. Optimal Sensor Placement for Structures Under Parametric Uncertainty
- Author
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Senthil Murugan, Michael I. Friswell, Rafael Castro-Triguero, and Rafael Gallego
- Subjects
Mathematical optimization ,symbols.namesake ,Truss bridge ,Rank (linear algebra) ,Robustness (computer science) ,Computer science ,Modal analysis ,symbols ,Fisher information ,Energy matrix ,Parametric statistics - Abstract
This paper examines the influence of parametric uncertainties on the optimal sensor placement methodologies for modal analysis of a truss bridge. Four classical sensor location methodologies are employed: two based on the Fisher information matrix and two based on energy matrix rank optimization. Young’s modulus, mass density and cross sectional dimensions are considered as uncertain parameters. The independent effects and cumulative effects of these uncertain variables on the sensor configuration are studied. The optimal locations of sensors under parametric uncertainty are assessed by the use of three different criteria. Furthermore, the robustness of this configuration is investigated for different levels of signal-to-noise ratio. The numerical results show the parametric uncertainties have significant influence on the optimal sensor configuration of a truss bridge.
- Published
- 2013
74. Long term evaluation of operating reserve with high penetration of renewable energy sources
- Author
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Warlley S. Sales, Manuel A. Matos, Armando M. Leite da Silva, and Mauro Rosa
- Subjects
Electric power system ,Engineering ,Wind power ,Operating reserve ,business.industry ,Monte Carlo method ,Intermittent energy source ,Electrical engineering ,business ,Energy source ,Energy matrix ,Reliability engineering ,Renewable energy - Abstract
Due to the high penetration of renewable energy into the energy matrix of today's power networks, the design of generating systems based only on static reserve assessment does not seem to be enough to guarantee the security of power system operation. From the wind power integration perspective, this energy source imposes additional requirements, mainly due to the inherent unpredictable characteristic of the wind. Besides the uncertainties in load and generating unit availabilities, the operating reserve needs also to deal with the fluctuation characteristic of the wind power. Therefore, more flexibility of the conventional generators (hydro and thermal) is required to provide system support services. This paper discusses a new methodology based on chronological Monte Carlo simulation to evaluate the operating reserve requirements of generating systems with large amounts of renewable energy sources, in particular, wind power.
- Published
- 2011
75. A cadeia produtiva de gás natural no Rio Grande do Norte e perspectivas para o setor
- Author
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Santos, Nely Ferreira dos, Nunes, Emanoel Márcio, and Apolinário, Valdênia
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Processo de inovação ,Rio Grande do Norte ,Gás natural ,Matriz energética ,Natural gas ,Supply chain ,Innovation process ,Cadeia produtiva ,CIENCIAS SOCIAIS APLICADAS::ECONOMIA [CNPQ] ,Energy matrix - Abstract
The paper demonstrates how it is organized production chain of natural gas in Rio Grande do Norte and highlights some prospects for this sector. The study is backed by elements to understand the process of innovation as the driving force of capitalist dynamics as well as the features of the Brazilian economy in the years 1990 and 2000 that indicated the development of natural gas production in the energy matrix Brazil. It was found that the state has potiguar possibilities for structuring an energy based on elements from the region and with prospects of becoming self-sufficient in electricity, where natural gas has a share of participation in this segment. The automotive and industrial are the biggest consumers of this input. With emphasis on the textile industry. Signaling to a broad horizon of supply, this sector will depend on their investments in research and Deficient, and the policy adopted by government to develop the consumer market O trabalho demonstra como está organizada a cadeia produtiva de gás natural no Rio Grande do Norte e ressalta algumas perspectivas para este setor. O estudo está respaldado pelos elementos que permitem compreender o processo de inovação enquanto força motriz da dinâmica capitalista, bem como os aspectos que caracterizam a economia brasileira nos anos de 1990 e 2000 e, que sinalizaram para o desenvolvimento da produção de gás natural na matriz energética brasileira. Constatou-se que o estado potiguar tem possibilidades de estruturar uma matriz energética embasada em elementos da própria região e com perspectivas de se tornar auto-suficiente em energia elétrica, onde o gás natural tem uma parcela de participação neste segmento. O setor automotivo e industrial são os maiores consumidores desse insumo. Com destaque para a indústria têxtil. Sinalizando para um horizonte amplo de oferta, este setor dependerá de investimentos e pesquisas em sua infraestrura, e da política adotada pelo governo para desenvolver o mercado consumidor
- Published
- 2011
76. Identification of induced lightning and direct striking based on wavelet transform
- Author
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Xie Bo, Sima Wenxia, Yuan Tao, and Yang Qing
- Subjects
Engineering ,Electric power transmission ,Transmission line ,business.industry ,Overvoltage ,Electronic engineering ,Wavelet transform ,Fault (power engineering) ,Topology ,business ,Lightning ,Time–frequency analysis ,Energy matrix - Abstract
Based on the different discharge processes of lightning striking, lightning overvoltage can be divided into two types: induced lightning overvoltage and direct lightning striking overvoltage (including back-flash and shielding failure). The characteristics of these overvoltages are investigated in this paper and it is concluded that induced lightning overvoltage exists simultaneously in three phases of the transmission line and similarity of its inter-phase is more significant than that of direct striking lightning overvoltage. Therefore the energy matrix similarity dependent method with the implement of wavelet transform can be applied to identify them. Mass simulation with consideration for many different fault conditions has been computed to prove its effectiveness based on ATP.
- Published
- 2010
77. Final report on key comparison CCQM-K100: Analysis of copper in ethanol
- Author
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Elias Kakoulides, Rodrigo Caciano de Sena, Yu. A. Kustikov, Gabriel F. Sarmanho, David Saxby, Janaína Marques Rodrigues, Pranee Phukphatthanachai, Oktay Cankur, Guillaume Labarraque, Olaf Rienitz, Tao Zhou, Suleyman Z Can, Werickson Fortunato de Carvalho Rocha, Charun Yafa, Reinhard Jaehrling, Yanbei Zhu, Leonid Konopelko, and Lindomar Augusto dos Reis
- Subjects
Measurement method ,Certified reference materials ,Waste management ,General Engineering ,Key (cryptography) ,Environmental science ,Standard uncertainty ,Mutual recognition ,Crude oil ,Energy matrix - Abstract
The increase in renewable sources in the energy matrix of the countries is an effort to reduce dependency on crude oil and the environmental impacts associated with its use. In order to help overcome the lack of widely accepted quality standards for fuel ethanol and to guarantee its competitiveness in the international trade market, the NMIs have been working to develop certified reference materials for bio-fuels and measurement methods. Inorganic impurities such as Cu, Na and Fe may be present in the fuel ethanol and their presence is associated with corrosion and the formation of oxide deposits in some engine parts. The key comparison CCQM-K100 was carried out under the auspices of the Inorganic Analysis Working Group (IAWG) and the coordination of the National Institute of Metrology, Quality and Technology (INMETRO). The objective of this key comparison was to compare the measurement capabilities of the participants for the determination of Cu in fuel ethanol. Ten NMIs participated in this exercise and most of them used the isotopic dilution method for determining the amount of Cu. The median was chosen as key comparison reference value (KCRV). The assigned KCRV for the Cu content was 0.3589 ?g/g with a combined standard uncertainty of 0.0014 ?g/g. In general, there is a good agreement among the participants' results. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
- Published
- 2014
78. Exergy analysis of BIGGT and EFGT cycles
- Author
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Sandro Barros Ferreira, Sergio Leal Braga, and Paula de Mello Ribeiro Pinto
- Subjects
Gas turbines ,Exergy ,General Energy ,Natural gas ,business.industry ,Environmental engineering ,Environmental science ,Biomass ,Thermodynamics ,business ,Average cost ,Energy matrix - Abstract
Availability of biomass in Brazil makes this fuel a major candidate to increase its presence in the country's energy matrix. In North-eastern Brazil, biomass available from sugarcane industry represents an annual energy resource of 146 PJ at an average cost of US$ 1.5/GJ. This paper aims to analyse the match between biomass and gas turbines. Two types of power plants are studied: the BIGGT and the EFGT cycles. The method involves design point exergoeconomic analysis, in order to identify major sources of exergy destruction and devices that can be thermodynamically enhanced. Results are compared with the Natural Gas Fuelled cycle.
- Published
- 2008
79. Studies in perturbation theory
- Author
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Per-Olov Löwdin
- Subjects
Power series ,Fermi contact interaction ,Differential equation ,Existential quantification ,Diagonal ,Perturbation (astronomy) ,Of the form ,Basis function ,Expectation value ,Schrödinger equation ,Matrix (mathematics) ,symbols.namesake ,Variational principle ,Quantum mechanics ,Applied mathematics ,Molecule ,Orthonormal basis ,Physical and Theoretical Chemistry ,Dirac sea ,Wave function ,Contraction (operator theory) ,Iteration process ,Eigenvalues and eigenvectors ,Spectroscopy ,Spin-½ ,Mathematical physics ,Mathematics ,Energy matrix ,Physics ,Degenerate energy levels ,Eigenfunction ,Atomic and Molecular Physics, and Optics ,Poincaré–Lindstedt method ,Nonlinear system ,Variational method ,Classical mechanics ,Dirac fermion ,Dirac equation ,Quantum electrodynamics ,Secular equation ,Two-body Dirac equations ,symbols ,Condensed Matter::Strongly Correlated Electrons ,Perturbation theory (quantum mechanics) ,Hamiltonian (quantum mechanics) ,Subspace topology - Abstract
Part II . The solution of the Schrodinger equation by means of the variation principle and a discrete basis leads to a certain secular equation. In a previous paper (Part I), it was shown that, if this equation is handled by a partitioning technique, a generalization of the Schrodinger-Brillouin formula is obtained. The procedure contains an inverse matrix, and it is shown here that, if in the expression for the wave function this matrix is approximated to the n th order, the corresponding matrix in the expectation value for the energy is approximated to order (2 n + 1). This gives a simple derivation and generalization of the Brillouin-Wigner theorem. The connection between the variation principle and perturbation theory is further discussed. Part III . The solution of the Schrodinger equation by means of the variation principle and a discrete but not necessarily orthonormal basis is studied in the case when the Hamiltonian H = H ( α ) is a function of a parameter α. The coefficients in the power series expansions in α of the wave function and the energy are explicitly determined in the form of expectation values, and the connection with the conventional Schrodinger theory is discussed.
- Published
- 1964
80. Die Störung der 4p2P-Terme durch Komplexterme im Kupfer I-Spektrum. II
- Author
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M. Elbel
- Subjects
Physics ,Crystallography ,Amplitude ,General Physics and Astronomy ,Hyperfine structure ,Energy matrix - Abstract
Refined values of the hyperfine constants A (4p2P1/2) and A(4p2P3/2) as well as B (4p2P3/2) required a new analysis of the perturbation of the 3d10 4p2P-levels by the [3d9 (4s4p)1P]2P- and [3d9 (4s4p)2P]2P-levels in Cu I-spectrum. The improved amplitudes α, β, γ referring to these three states are . The values in brackets coming from part I of this publication are out of date now. The phases of the amplitudes β, Γ with respect to α cannot be ascertained from the magnetic hyperfine constants because of the absence of interfering matrix elements between 3d10 4p- and 3d9 4s 4p- states. But the upper choice of phases turns out to be the right one if one deduces from α, β, γ the Slater parameters of the perturbation. One finds J = R2 (3d4p, 4s4p)/5 = 1431 cm−1 and K = R1(3d4p, 4p4s)/3 = 2609 cm−1. Unfortunately the values J = 1882 cm−1, K = 1077 cm−1 quoted by BUDICK and LEVIN are wrong. They have been deduced from an energy matrix wich was not phase consistent with the basis of magnetic hyperfine constants given in a former paper of the author and used throughout part I of this publication.
- Published
- 1969
81. Theorie der Riesenresonanzen in sph�rischen Kernen
- Author
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Walter Greiner, Hans Weber, and Max G. Huber
- Subjects
Physics ,Nuclear and High Energy Physics ,Dipole ,Cross section (physics) ,Operator (physics) ,Quantum mechanics ,Nuclear Theory ,Structure (category theory) ,Nuclear fusion ,Energy matrix - Abstract
The dynamic collective theory has been developed for vibrational nuclei in a previous paper. Here the details are studied and compared with experiments. For this purpose the structure of the dipole operator has been established, the energy matrix of the dipole-quadrupole interaction has been diagonalized and the various approximations are discussed quantitatively in detail. It is interesting that this systematic theory gives the details of theγ-absorption cross section in many nuclei.
- Published
- 1966
82. Hückel Valence Bond Theory of Stereoselection
- Author
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H. L. Eaton, J. R. Larson, and N. D. Epiotis
- Subjects
Modern valence bond theory ,Theoretical physics ,Chemical coupling ,Real systems ,Hückel's rule ,Valence bond theory ,Generalized valence bond ,Energy matrix - Abstract
Why should we pursue an understanding of aromaticity and antiaromaticity on the basis of HVB theory? The first and most important reason is that HVB theory is equivalent to the theory which is the foundation of most present day concepts of chemistry: HMO theory with neglect of overlap. Secondly, an HVB treatment of steroselection has never been presented before. Accordingly, this section fills a void in the theoretical literature. Thirdly, the HVB theory of model systems constitutes preparation for the VB theory of real systems to be presented in following papers. Finally, HVB theory is the simplest illustrator of the conceptual advantages of the VB method, in a general sense. It is the first obligatory step along the pedagogical route leading to ultimate mastery of rigorous VB theory.
- Published
- 1982
83. Spatialized potential for biomass energy production in Brazil: an overview
- Author
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Ribeiro, Ana Pimenta and Rode, Michael
- Subjects
Renewable energy ,Sustainable development ,Energy security ,ddc:500 ,Biomass ,Dewey Decimal Classification::500 | Naturwissenschaften ,Energy matrix ,New technologies - Abstract
The opportunity for renewable energy production in developing countries is a theme of high relevance within the context of climate change. In this paper we explore the production of electricity in Brazil and investigate the potential for sustainable biomass energy production. This is explored in a GIS system (1) establishing the demand centers or regions (energy demand factor), (2) checking if they can be served by existing capacity and transmission (transmission lines factor), (3) deciding on new generation and whether it will an island or the main grid connection (power plants factor), (4) locating the power plant subject to the potential biomass supply accepting the environmental constraints (land use and environmental preservation factors). Results show that even though large areas have a potential for biomass energy production, the lack of investments in technological improvements and changes in the system status quo result in a system that does not progress towards of becoming a cleaner, safer and less dependent on climatic factors. We conclude that biomass has the potential to grow as a source of renewable and clean energy. This potential can be explored by conserving respecting the environment and encouraging the creation of decentralized systems, thereby making Brazil a key player in the climate change targets in the coming years. Brazilian research incentive program Science Without Borders
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- View/download PDF
84. SUSTENTABILIDAD EMPRESARIAL, SEGURIDAD ENERGÉTICA Y ÉTICA AMBIENTAL EN CHILE
- Author
-
Andrés Suárez
- Subjects
matriz energética ,ecología ,Health (social science) ,Chilena ,biology ,Health Policy ,Welfare economics ,Political science ,sustentabilidad ,biology.organism_classification ,Business development ,Energy matrix - Abstract
This paper explores the relation between business sustainability, both linked to financial profit as well as to relations with local organizations, and the environment, in a context of an internationalized economy such as the Chilean economy. Likewise, it analyzes recent conflicts originated in Chile for energy supply and the difficulties in defining an energy matrix. Finally, the article analyzes the influence of ecological ethics in the preservation of the high diversity ecosystems in the South of Chile, facing the business development and the specific energy projects. Sustentabilidade empresarial, seguranca energetica e etica ambiental no Chile Resumo: O artigo explora a relacao entre sustentabilidade empresarial —associada tanto a rentabilidade financeira como as relacoes com coletivos locais— e o meio ambiente, no contexto de uma economia internacionalizada como a chilena. Do mesmo modo, analisa conflitos recentes originados no Chile para o provimento de energia e as dificuldades na definicao de uma matriz energetica, e, finalmente, a influencia da etica ecologica para a preservacao dos ecossistemas de alta biodiversidade no sul do Chile, frente ao desenvolvimento empresarial e aos projetos energeticos, especificamente.
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