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Diagnóstico técnico institucional da recuperação e uso energético do biogás gerado pela digestão anaeróbia de resíduos; Technical diagnostics of institutional recovery and energy use of biogas generated by anaerobic digestion of waste

Alves, João Wagner Silva
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/11/2000 PT
Relevância na Pesquisa
35.9%
O objetivo deste trabalho é discutir as principais ações para que iniciativas de recuperação e uso de biogás gerado por resíduos sejam bem sucedidas. A discussão se inicia com informações a respeito do aumento do efeito estufa e da escassez de recursos naturais. O Brasil, um país em desenvolvimento, deve promover melhorias sanitárias em todos os níveis: coleta e disposição de resíduos sólidos, esgotamento e tratamento dos esgotos domésticos e comerciais e contenção e tratamento de fluentes industriais. O país deve também otimizar o uso de seus recursos energéticos preservando a qualidade ambiental. Ao final da Rio 92, o Governo Brasileiro assumiu o compromisso de realizar inventários de emissões dos GEE. Nestes se inclui o inventário de emissões de metano gerado pela degradação anaeróbia de resíduos. Sabe-se que, pela degradação anaeróbia dos resíduos, em 1.990, o Brasil emitia cerca de 800Gg de metano ao ano e estima-se 900Gg para o ano de 2.000. Nesse total não se identifica nenhuma iniciativa de recuperação energética bem sucedida em andamento. A maior parte do biogás é gerada pela degradação dos resíduos sólidos. Para que se promova a recuperação do biogás nos locais de disposição de resíduos sólidos (LDRS) deve-se...

Fluxos de energia aplicada à produção de biomassa; Energy flows applied to biomass production

Arruda Junior, Antonio Morelli
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/01/2013 PT
Relevância na Pesquisa
45.94%
A crescente demanda por alimento e o aumento do uso de energias renováveis exigem cada vez mais o aumento da produtividade agrícola. Neste cenário, ferramentas e metodologias que possam monitorar as dinâmicas de sistemas agrícolas, são cada vez mais necessárias. Esse trabalho propõe a investigação da interferência de fluxos de energia de origem antrópica na produtividade por meio da biomassa obtida. Tendo como referência os estudos de Schneider e Kay (1992) sobre eficiência e transferência energética entre níveis tróficos e seus efeitos nos ecossistemas, os estudos foram concentrados em três áreas de diferentes características quanto às ações antrópicas: cana-de-açúcar, eucalipto e floresta natural. Utilizando cálculos de balanço energético por fluxo de massa e o balanço radiométrico, buscou-se verificar se a entrada de energia via atividades agrícolas, afetou a capacidade de degradação energética do cultivo e sua conversão em biomassa. Os estudos radiométricos foram realizados a partir dos valores de onda longa emitida e onda curta incidente, extraídos das imagens de satélite Lansat 5 por meio do algoritmo de SEBAL (Surface Energy Balance Algorithm for Land), que ainda forneceu os dados de saldo de radiação para complemento dos estudos. Os resultados obtidos indicaram que a entrada de energia antrópica nos sistemas não alterou os valores referentes à degradação energética...

Comparação entre diferentes processos de degradação do antibiótico sulfametoxazol; Comparison between different processes for degradation of antibiotic sulfamethoxazole

Hussain, Sajjad
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/02/2014 PT
Relevância na Pesquisa
35.91%
A ocorrência de produtos farmacêuticos e de cuidados pessoais no meio ambiente tem levado a preocupações sobre seu impacto ambiental e à saúde pública. O sulfametoxazol (SMX) é um fármaco que tem sido encontrado amplamente no ambiente. Neste estudo foi verificada a eficácia de vários processos, a saber eletroquímico, eletroquímico foto assistido, fotoquímico, Fenton e foto-Fenton, para a degradação de SMX em solução aquosa. A degradação eletroquímica e eletroquímica foto assistida foram realizadas em uma célula de fluxo do tipo filtro-prensa, usando um ânodo dimensionalmente estável comercial com composição nominal Ti/Ru0,3Ti0,7O2. Durante ambos os processos, efeitos de diferentes parâmetros foram analisados, como a natureza do eletrólito, a concentração de eletrólito suporte (NaCl) e a densidade de corrente aplicada. Os experimentos fotoquímicos, Fenton e foto-Fenton foram realizados em um reator de vidro cilíndrico de compartimento único. O efeito das concentrações inicias de Fe2+ e de H2O2 foram estudados para os processos Fenton e foto-Fenton. Similarmente, o efeito do pH inicial, a concentração inicial do SMX e a temperatura foram investigados para todos os processos. A variação da concentração de SMX foi determinada por cromatografia líquida de alta eficiência (CLAE) e a quantidade de matéria orgânica foi monitorada por análise de carbono orgânico total (COT). Os resultados obtidos indicaram que o SMX foi completamente degradado...

Using shifts in the electronic emission curve to evaluate polymer surface degradation

Chinaglia, D. L.; Hessel, R.; Oliveira, O. N.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 97-101
ENG
Relevância na Pesquisa
35.93%
The polymer surface degradation and/or modification evolution of Teflon FEP and Mylar C films caused by a low energy electron beam were analyzed using a new method that consists in measuring the second crossover energy shift in the electronic emission curve. Upon prolonged irradiation, the second crossover energy shifts irreversibly to lower values in Teflon FEP but to higher values in Mylar C, indicating distinct mechanisms of surface degradation for the two polymers. The method represents a relatively inexpensive way to monitor early stages of surface degradation since the secondary electron emission comes from a maximum depth below the geometric surface of 100 mn in insulators. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Studies on thermal-oxidative degradation behaviours of raw natural rubber: PRI and thermogravimetry analysis

Danielle Galiani, P.; Antonio Malmonge, J.; Guenther Soares, B.; Henrique Capparelli Mattoso, L.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 334-339
ENG
Relevância na Pesquisa
35.95%
Thermal-oxidative degradation behaviours of raw natural rubber (NR) have been investigated by using thermogravimetry analysis in inert and oxidative atmospheres and the plasticity retention index (PRI). The activation energy E a, was calculated using Horowitz-Metzger and Coats-Redfern methods and compared with PRI. The E a values obtained by each method were in good agreement with each other. The June samples are the least stable rubbers among the studied ones, whereas February samples exhibited the highest values of activation energy, therefore in agreement with the PRI behaviour, which indicates that the thermo-oxidative stability of the June samples are the poorest during the thermo-oxidative degradation reaction. Natural rubber is a product of biological origin, and thus these variations in the values of thermal behaviour and PRI might be related to the genetic differences and alterations of climatic conditions that act directly on the synthesis of non-rubber constituents, which are generally reflected in latex and rubber properties. © 2013 Institute of Materials, Minerals and Mining.

Estudo de nova configuração de colunas de destilação aumentando eficiência energética; Study of a new set of distillation columns for increasing energy efficiency

Gustavo Henrique Santos Florês Ponce
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 14/04/2011 PT
Relevância na Pesquisa
45.73%
O objetivo dessa dissertação foi o de comparar, através de simulações utilizando o software Aspen Plus® os gastos energéticos de uma coluna de destilação usual com relação a uma Coluna de Destilação com Integração Interna de Calor (CDIIC), para o mesmo fim. A destilação é um processo que consome muita energia sendo que possui uma baixa eficiência energética (em torno de 10%). A CDIIC atua aumentando a temperatura da seção de retificação colocando esta em contato direto com a seção de esgotamento, fazendo-as trocar calor, provendo parte, ou toda energia, necessária a ser adicionada e retirada da coluna. Trata-se de uma recente tecnologia com a vantagem de uma menor degradação energética ao longo da coluna e, conseqüente, maior eficiência. Nas simulações foram realizadas concentrações (em percentual mássico de etanol) de uma mistura de etanol - água a 92,6% a partir da concentração que a mistura de vinho fermentado de-levedurado do processo batelada alimentada contendo 8% em massa. A mistura etanol-água foi estudada porque hoje existe um grande interesse no Brasil em tecnologias que diminuam o seu custo de produção. Sendo a destilação a etapa fundamental do processo de concentração dessa mistura...

Identificação e caracterização de medidas de eficiência energética e de produção - utilização de energia renovável no parque habitacional português; Identification and caracterization of energy efficiency measures and renewable energy production - utilization measures in Portuguese residential building stock

Tavares, Diogo Filipe Lima
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Trabalho de Conclusão de Curso
Publicado em //2013 POR
Relevância na Pesquisa
35.96%
Dissertação de mestrado integrado em Engenharia Civil (área de especialização em Perfil de Construções); Ao longo do século passado, em virtude de um crescimento populacional exponencial, a indústria da construção sofreu grandes alterações que contribuíram em larga escala para o consumo desmedido de recursos naturais, a degradação de ecossistemas, a produção excessiva de resíduos, a poluição atmosférica e consequente degradação do planeta. A par disto existe atualmente uma grande dependência dos combustíveis fósseis, o que, conciliado com as elevadas necessidades energéticas da indústria da construção, originou uma dependência energética externa na UE. Neste contexto têm vindo a ser feitos esforços para a redução do impacto da indústria da construção na degradação do planeta e na dependência energética externa, sendo a diminuição do consumo e a alteração das fontes de energia, utilizada nos edifícios, parte fundamental da solução. Como tal, a reabilitação energética assume-se como fulcral em nome da redução do consumo energético e na mudança das fontes de energia. É portanto relevante o estudo da reabilitação energética não só numa vertente de obtenção da maior rentabilidade...

Stochastic modeling of the thermal and catalytic degradation of polyethylene using simultaneous DSC/TG analysis

Trindade, Nuno Miguel Passarinho
Fonte: Faculdade de Ciências e Tecnologia Publicador: Faculdade de Ciências e Tecnologia
Tipo: Dissertação de Mestrado
Publicado em //2012 ENG
Relevância na Pesquisa
35.91%
Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica; In the present work a stochastic model to be used for analyzing and predicting experimental data from simultaneous thermogravimetric (TG) and differential scanning calorimetry (DSC) experiments on the thermal and catalytic degradation of high-density polyethylene (HDPE) was developed. Unlike the deterministic models, already developed, with this one it’s possible to compute the mass and energy curves measured by simultaneous TG/DSC assays, as well as to predict the product distribution resulting from primary cracking of the polymer, without using any experimental information. For the stochastic model to predict the mass change as well as the energy involved in the whole process of HDPE pyrolysis, a reliable model for the cracking reaction and a set of vaporization laws suitable to compute the vaporization rates are needed. In order to understand the vaporization process, this was investigated separately from cracking. For that, a set of results from TG/DSC experiments using species that vaporize well before they crack was used to obtain a global correlation between the kinetic parameters for vaporization and the number of C-C bonds in the hydrocarbon chain. The best fitting curves were chosen based on the model ability to superimpose the experimental rates and produce consistent results for heavier hydrocarbons. The model correlations were implemented in the program’s code and allowed the prediction of the vaporization rates. For the determination of the global kinetic parameters of the degradation reaction to use in the stochastic model...

MDM2 Promotes Proteasomal Degradation of p21Waf1 via a Conformation Change*

Xu, Hongxia; Zhang, Zhuo; Li, Mao; Zhang, Ruiwen
Fonte: American Society for Biochemistry and Molecular Biology Publicador: American Society for Biochemistry and Molecular Biology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
35.9%
MDM2 plays a major role in cancer development and progression via both p53-dependent and -independent functions. One of its p53-independent functions is the induction of the ubiquitin-independent proteasomal degradation of p21Waf1. The present study was designed to characterize the mechanism(s) by which MDM2 induces p21Waf1 degradation. We first determined the regions of MDM2 required for p21Waf1 degradation using pulldown assays and Western blotting and then examined the mechanisms using limited proteolysis and fluorescence resonance energy transfer assays. We found that the MDM2-p21Waf1 interaction depended on the central domain of MDM2 and that nuclear localization of both proteins was necessary for p21Waf1 degradation. Specifically, amino acids 226–250 of MDM2 were required for p21Waf1 binding and degradation, and amino acids 251–260 were necessary for p21Waf1 degradation. The latter region induced a conformation change in p21Waf1, increasing its interaction with the C8 subunit of the proteasome, leading to its degradation. When MDM2 lacked either segment (aa 226–250 or aa 251–260), its capacity to promote p21Waf1 degradation and cell cycle progression was significantly reduced. In summary, the present study elucidated a previously unknown mechanism by which MDM2 promotes the degradation of an intact protein (p21Waf1) through an ubiquitin-independent proteasomal degradation pathway. Because MDM2 also increases the degradation of other proteins in a ubiquitin-independent manner...

Iran - Energy : Environment Review Policy Note

World Bank
Fonte: Washington, DC Publicador: Washington, DC
EN_US
Relevância na Pesquisa
36%
This Policy Note is based on the Final Report of the Environmental Energy Review (EER), prepared over two years, with the full collaboration of the Government of Iran, and the assistance of international, and national consultants. The EER report comprises: an analysis of the current situation with regards to energy generation, and use; an evaluation of the growth prospects with regard to energy generation, and use; the identification of the environmental issues induced by the generation, and use of energy, and the cost estimates of damages; the evaluation of the extent of contribution to the climate-change phenomenon, through emission of greenhouse gases; the evaluation of the proposed mitigating measures for previously identified environmental problems; conclusions and recommendations; and, a proposal for an action plan. The emphasis of the EER is on air pollution, being the most extreme, visible sign of environmental damage, certainly in the large cities. The major source of air pollution is the energy sector, key to the Iranian economy...

Morocco : Cost Assessment of Environmental Degradation

World Bank
Fonte: Washington, DC Publicador: Washington, DC
EN_US
Relevância na Pesquisa
36.02%
This report is the first step in a process toward using environmental damage cost assessments for priority setting and as an instrument for integrating environmental issues into economic and social development. The report provides estimates of damage cost for several areas of the environment: air, water, land and forests, and waste disposal. The estimates should be considered as orders of magnitude and a range is provided to indicate the level of uncertainty. As areas of priority are identified, further analysis will be required for more accurate estimates. Due to data limitations, the damage cost of environmental degradation has not been estimated in several areas: industrial, hazardous, and hospital waste disposal; unsanitary landfills; degradation of natural ecosystems and biodiversity; and groundwater resource degradation and over-extraction. In addition and due to the complexity of the problem, the report only partially captures damage resulting from soil degradation. The report points t the need to further assess and quantify current and potential future damage costs related to those impacts.

Drell-Yan and J/psi Production in High Energy Proton-Nucleus and Nucleus-Nucleus Collisions

Gale, Charles; Jeon, Sangyong; Kapusta, Joseph
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 04/08/1999
Relevância na Pesquisa
45.7%
The distributions of outgoing protons and charged hadrons in high energy proton-nucleus collisions are described rather well by a linear extrapolation from proton-proton collisions. This linear extrapolation is applied to precisely measured Drell-Yan cross sections for 800 GeV protons incident on a variety of nuclear targets. The deviation from linear scaling in the atomic number A can be accounted for by energy degradation of the proton as it passes through the nucleus if account is taken of the time delay of particle production due to quantum coherence. We infer an average proper coherence time of 0.4 +/- 0.1 fm/c. Then we apply the linear extrapolation to measured J/psi production cross sections for 200 and 450 GeV/c protons incident on a variety of nuclear targets. Our analysis takes into account energy loss of the beam proton, the time delay of particle production due to quantum coherence, and absorption of the J/psi on nucleons. The best representation is obtained for a coherence time of 0.5 fm/c, which is consistent with Drell-Yan production, and an absorption cross section of 3.6 mb, which is consistent with the value deduced from photoproduction of the J/psi on nuclear targets. Finally, we compare to recent J/psi data from S+U and Pb+Pb collisions at the SPS. The former are reproduced reasonably well with no new parameters...

Monte Carlo model of electron energy degradation in a CO2 atmosphere

Bhardwaj, Anil; Jain, Sonal Kumar
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 19/11/2010
Relevância na Pesquisa
35.9%
A Monte Carlo model has been developed to study the degradation of <1000 eV electrons in an atmosphere of CO2, which is one of the most abundant species in Mars' and Venus' atmospheres. The e-CO2 cross sections are presented in an assembled set along with their analytical representations. Monte Carlo simulations are carried out at several energies to calculate the "yield spectra", which embodied all the information related to electron degradation process and can be used to calculate "yield" (or population) for any inelastic process. The numerical yield spectra have been fitted analytically resulting in an analytical yield spectra (AYS). We have calculated the mean energy per ion pair and efficiencies for various inelastic processes, including the double and dissociative double ionization of \car\ and negative ion formation. The energy distribution of the secondary electrons produced per incident electron is also presented at few incident energies. The mean energy per ion pair for CO2 is 37.5 (35.8) eV at 200 (1000) eV, compared to experimental value 32.7 eV at high energies. Ionization is the dominant loss process at energies above 50 eV with contribution of ~50%. Among the excitation processes, 13.6 eV and 12.4 eV states are the dominant loss processes consuming ~28% energy above 200 eV. Around and below ionization threshold...

Goals for teacher learning about energy degradation and usefulness

Daane, Abigail R.; Vokos, Stamatis; Scherr, Rachel E.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.99%
The Next Generation Science Standards (NGSS) require teachers to understand aspects of energy degradation and the second law of thermodynamics, including energy's availability and usefulness, changes in energy concentration, and the tendency of energy to spread uniformly. In an effort to develop learning goals that support teachers in building robust understandings of energy from their existing knowledge, we studied teachers' impromptu conversations about these topics during professional development courses about energy. Many of these teachers' ideas appear to align with statements from the NGSS, including the intuition that energy can be present but inaccessible, that energy can change in its usefulness as it transforms within a system, and that energy can lose its usefulness as it disperses, often ending up as thermal energy. Some teachers' ideas about energy degradation go beyond what is articulated in the NGSS, including the idea that thermal energy can be useful in some situations and the idea that energy's usefulness depends on the objects included in a scenario. Based on these observations, we introduce learning goals for energy degradation and the second law of thermodynamics that (1) represent a sophisticated physics understanding of these concepts...

Comparative Energy Dependence of Proton and Pion Degradation in Diamond

Lazanu, I.; Lazanu, S.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 15/04/1999
Relevância na Pesquisa
35.93%
A comparative theoretical study of the damages produced by protons and pions, in the energy range 50 MeV - 50 GeV, in diamond, is presented. The concentration of primary defects (CPD) induced by hadron irradiation is used to describe material degradation. The CPD has very different behaviours for protons and pions: the proton degradation is important at low energies and is higher than the pion one in the whole energy range investigated, with the exception of the Delta33 resonance region, where a large maximum of the degradation exists for pions. In comparison with silicon, the most investigated and the most studied material for detectors, diamond theoretically proves to be one order of magnitude more resistant, both to proton and pion irradiation.; Comment: 7 pages, 5 figures

Coherence Time in High Energy Proton-Nucleus Collisions

Gale, C.; Jeon, S.; Kapusta, J.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 18/08/1998
Relevância na Pesquisa
45.66%
Precisely measured Drell-Yan cross sections for 800 GeV protons incident on a variety of nuclear targets exhibit a deviation from linear scaling in the atomic number A. We show that this deviation can be accounted for by energy degradation of the proton as it passes through the nucleus if account is taken of the time delay of particle production due to quantum coherence. We infer an average proper coherence time of 0.4 +- 0.1 fm/c, corresponding to a coherence path length of 8 +- 2 fm in the rest frame of the nucleus.; Comment: 11 pages in LaTeX. Includes 6 eps figures. Uses epsf.sty

Baryon, Charged Hadron, Drell-Yan and J/Psi Production in High Energy Proton-Nucleus Collisions

Gale, Charles; Jeon, Sangyong; Kapusta, Joseph
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/03/1999
Relevância na Pesquisa
45.7%
We show that the distributions of outgoing protons and charged hadrons in high energy proton-nucleus collisions are described rather well by a linear extrapolation from proton-proton collisions. The only adjustable parameter required is the shift in rapidity of a produced charged meson when it encounters a target nucleon. Its fitted value is 0.16. Next, we apply this linear extrapolation to precisely measured Drell-Yan cross sections for 800 GeV protons incident on a variety of nuclear targets which exhibit a deviation from linear scaling in the atomic number A. We show that this deviation can be accounted for by energy degradation of the proton as it passes through the nucleus if account is taken of the time delay of particle production due to quantum coherence. We infer an average proper coherence time of 0.4 +/- 0.1 fm/c, corresponding to a coherence path length of 8 +/- 2 fm in the rest frame of the nucleus. Finally, we apply the linear extrapolation to measured J/Psi production cross sections for 200 and 450 GeV/c protons incident on a variety of nuclear targets. Our analysis takes into account energy loss of the beam proton, the time delay of particle production due to quantum coherence, and absorption of the J/Psi on nucleons. The best representation is obtained for a coherence time of 0.5 fm/c...

Monitoring land degradation risk using ASTER data: The non-evaporative fraction as an indicator of ecosystem function

García García, Mónica; Oyonarte, Cecilio; Villagarcía, Luis; Contreras, Sergio; Domingo, Francisco; Puigdefábregas, Juan
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 3039306 bytes; application/pdf
ENG
Relevância na Pesquisa
35.94%
17 pages, 10 figures.-- Printed version published on Sep 15, 2008.; Author's version available at: http://www.eeza.csic.es/eeza/documentos/Elsevier_Garcia_2008.pdf; There is a need to develop operational land degradation indicators for large regions to prevent losses of biological and economic productivity. Disturbance events press ecosystems beyond resilience and modify the associated hydrological and surface energy balance. Therefore, new indicators for water-limited ecosystems can be based on the partition of the surface energy into latent (λE) and sensible heat flux (H).; In this study, a new methodology for monitoring land degradation risk for regional scale application is evaluated in a semiarid area of SE Spain. Input data include ASTER surface temperature and reflectance products, and other ancillary data. The methodology employs two land degradation indicators, one related to ecosystem water use derived from the non-evaporative fraction (NEF = H / (λE + H)), and another related to vegetation greenness derived from the NDVI. The surface energy modeling approach used to estimate the NEF showed errors within the range of similar studies (R^2 = 0.88; RMSE = 0.18 (22%)).; To create quantitative indicators suitable for regional analysis...

Good for people can be good for business: The convergence of opportunities for delivering basic energy to low-income households in developing countries

Balmer,Marlett; Hancock,David
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
45.76%
Energy poverty affects more than 40% of the world's population. Fuels and appliances used by low-income groups have been of low-quality, expensive, non-durable and have posed serious health and safety risks to users. Energy transition theories, most noteably the energy ladder model, have postulated a gradual but complete move away from traditional, mostly biomass energy sources towards modern energy sources. Evidence however, increasingly indicates that the process did not happen as anticipated. This paper argues that energy transition from biomass fuels to full electricity use will not take place in SADC countries due to economic circumstances, increases in commercial fuel prices and the deficit in power generation capacity in the region. It further argues that wood fuel, traditionally regarded as a lower order fuel, is actually a renewable energy source that can meet the energy needs of rural people sustainably, if managed correctly. The paper suggests a re-evaluation of the value of wood fuel - from a low value fuel associated with poverty and degradation to a high value, renewable energy fuel, supplying much needed energy in a potentially sustainable manner. The paper outlines a convergence of a number of external conditions and opportunities which may alter household energy supply...

A review of electrical energy management techniques: Supply and consumer side (industries)

Mohamed,Afua; Khan,Mohamed Tariq
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
45.71%
A review of electrical energy management techniques on the supply side and demand side is presented. The paper suggests that direct load control, interruptible load control, and time of use (TOU) are the main load management techniques used on the supply side (SS). The supply side authorities normally design these techniques and implement them on demand side consumers. Load management (LM) initiated on the demand side leads to valley filling and peak clipping. Power factor correction (PFC) techniques have also been analysed and presented. It has been observed that many power utilities, especially in developing countries, have neither developed nor implemented DSM for their electrical energy management. This paper proposes that the existing PFC techniques should be re-evaluated especially when loads are nonlinear. It also recommends automatic demand control methods to be used on the demand side in order to acquire optimal energy consumption. This would lead to improved reliability of the supply side and thereby reducing environmental degradation.