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Contribuição para o estudo da influência da espessura, cor, opacidade e marca comercial das porcelanas feldspáticas na propagação da luz visível, através da Teoria de Kubelka Munk e suas implicações na odontologia, para os intervalos de comprimento de onda de 410500nm e de 410700nm; A contribution to the study of the influence of thickness, shade, opacity and commercial brands of feldspatic porcelains on the propagation of visible light, through the Kubelka Munk Theory and its implications in dentistry, for the wavelength intervals of 410500nm and 410 700nm

Steagall Junior, Washington
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 02/09/2009 PT
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O estudo da propagação da luz nas porcelanas é importante para entender seu comportamento óptico frente a situações clínicas como fotoativação de cimentos resinosos e sua resposta estética, quando observada sobre diferentes fundos. Este trabalho estudou a influência da espessura, cor, opacidade e marca comercial das porcelanas feldspáticas na propagação da luz visível, através da teoria de KubelkaMunk (KM), nos intervalos de comprimento de onda de 410500nm e de 410700nm. Foram confeccionados discos de 12,5mm por 1 mm de espessura de porcelana feldspática de duas opacidades, corpo (B) e corpo opaco (BO), das marcas Vintage Halo (HALO), Noritake Super Porcelain EX3 (NORI) e IPS dSIGN (IPS), nas cores A1, A35 e B3 (n=7). Os discos foram polidos através de uma série de lixas abrasivas até a granulação 600 e acondicionados individualmente em ambiente seco. Os discos tiveram suas curvas espectrais de refletância obtidos em contato óptico, sobre fundo branco e preto, através do uso de um espectrofotômetro com esfera de integração acoplada, no intervalo de comprimento de onda de 410700nm. As curvas de refletância foram inseridas na teoria KM, para obtenção e análise quantitativa e qualitativa das propriedades ópticas de cada material. As análises qualitativas envolveram a observação do comportamento espectral das curvas de espalhamento...

Nanoemulsões produzidas pelo método do ponto de inversão da emulsão (EIP) para encapsulação de curcumina: parâmetros de produção, estabilidade físico-química e incorporação em sorvete; Curcumin- loaded nanoemulsions produced by emulsion inversion point (EIP) method: process parameters, physico-chemical stability and incorporation in ice cream

Borrin, Thaís Ribeiro
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 13/07/2015 PT
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A curcumina possui uma grande variedade de propriedades benéficas para a saúde humana. Devido a este fato, a indústria alimentícia tem aumentado a aplicação deste bioativo como aromatizante, conservante e aditivo para substituição dos corantes amarelos artificiais. No entanto, incorporar a curcumina em formulações alimentícias pode ser problemático porque sua molécula hidrofóbica tem baixa solubilidade em água e é muito sensível à luz. Os métodos de encapsulação em nanoemulsões podem tornar viável a proteção do curcuminoide, bem como permitir sua dispersibilidade em água. O objetivo do presente trabalho de Mestrado foi produzir nanoemulsões encapsulando curcumina pelo método do ponto de inversão da emulsão (EIP, emulsion inversion point), determinando parâmetros de operação que viabilizem um futuro escalonamento do processo e incorporação das dispersões em sorvete de massa sabor abacaxi. Os parâmetros de produção foram ajustados como: tipo e concentração de tensoativo (razão SOR), concentração de óleo de soja, tipo e concentração de cosolvente, tipo de impelidor/ velocidade de agitação e vazão de entrada da fase aquosa. As porcentagens de curcumina encapsulada foram 0,03, 0,07 e 0,10%. Dentre estas...

Imobilização de invertase comercial e de Saccharomyces cerevisiae em sabugo de milho e bagaço de cana-de-açúcar

Santos, Andréa Francisco dos
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: 93 f.
POR
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Pós-graduação em Alimentos e Nutrição - FCFAR; Invertase ou β –D frutofuranosidase (EC 3.2.1.26) é uma enzima que catalisa a hidrólise do terminal não redutor do resíduo β- frutofuranosidase em frutofuranosídeos. A imobilização em suportes lignocelulósicos como resíduos bagaço de cana (BC) e resíduos de sabugo de milho (SM) são favoráveis, pois são suportes de baixo custo. A invertase comercial e extraída de Saccharomyces cerevisiae e os derivados foram caracterizadas enzimaticamente. O pH ótimo encontrado para os derivados foram bem próximas da encontrada para as invertases livres, em torno de pH 4,5 a 5,5. Os derivados apresentaram estabilidade térmica superior a das invertases livres e alguns derivados tiveram acréscimos na temperatura, como os derivados da invertase extraída obtido com pó BC e SM glutaraldeído e derivados da invertase comercial obtido com pó SM e BC amino e BC glioxil. A energia de ativação encontrada para a maioria dos derivados apresentou- se na faixa de 12 a 29 kJ/ mol, valores inferiores ao encontrados para as formas livres de invertase...

Parametros mecanicos no enfardamento do palhiço da cana-de-açucar; Mechanical parameters in bailing sugar cane straw

Evaldo Luiz Palermo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/08/1998 PT
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O palhiço da cana-de-açúcar, em função da sua produção em grande escala, e a atual situação energética do Brasil, tem sido considerada como uma importante fonte alternativa para minimizar a crise energética. Todavia se conhece pouco das suas propriedades mecânicas e dos parâmetros de enfardamento os quais podem melhorar a eficiência das operações de manuseio da palha. O trabalho foi elaborado com a finalidade de estudar o comportamento mecânico do palhiço da cana-de-açúcar em ensaios de compressão e relaxação, realizados em laboratório com a máquina de ensaio MTS empregando taxas de deformação de 10 mm/s, 20 mm/s, 30 mm/s, 40 mm/s e 43 mm/s. E, em campo, através da utilização da enfardadora prismática Nogueira AP 41N, devidamente instrumentada para registrar o sinal da força atuante na biela e a rotação da manivela de acionamento. A partir dos ensaios de compressão foram analisadas as curvas pressão versus densidade aparente, bem como uma avaliação do consumo energético e analise das curvas de relaxação em função das condições de ensaio adotadas. No ensaio com a enfardadora foi determinada a força axial média atuante na biela de 800 kgf, obtendo fardos com densidade média de 250 kg/m3. O grau de umidade apresentou influência na relação pressão x densidade...

Quantificação de resíduos do processamento de cinco espécies comerciais amazônicas e análise do potencial energético; Quantification of processing waste of five amazon commercial species and analysis of potential energy

Machado, Mayara Paula Oliveira
Fonte: Universidade de Brasília Publicador: Universidade de Brasília
Tipo: Dissertação
POR
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Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Florestal, 2015.; Este trabalho apresenta a analise da produção de resíduos em uma serraria de pequeno porte no município de Sena Madureira e teve por objetivos principais quantificar a biomassa seca e determinar o potencial energético dos resíduos gerados no processamento de cinco espécies comerciais amazônicas e como objetivo secundário caracterizar o resíduo quanto à sua qualidade energética. Como base metodológica, acompanhou-se o processamento de 73 toras: 16 toras da espécie Cedrela odorata L (cedro) em 12 horas; 20 toras da espécie Couratari spp (tauari) em 14 horas; 15 toras da espécie Eschweilera grandiflora (castanharana) em 8 horas; 12 toras da espécie Apuleia molaris Spruce ex Benth (garapa) coletadas em 12 horas e 10 toras da espécie Clarisia racemosa (guariúba) 4 horas, sendo quantificado o volume de tábuas produzidas e o volume de resíduos (serragem e pedaços). Para a determinação do volume de resíduos na forma de serragem, a espessura do fio de corte da serra de fita foi mensurada, determinando assim o volume antes mesmo que este fosse produzido. Foi retirada de casca-a-casca uma amostra de madeira para obtenção do teor de umidade e da densidade da tora na condição de pátio. Após a determinação da densidade e teor de umidade pátio as amostras foram divididas em duas partes: uma para determinação da densidade básica e outra após moagem e classificação para determinação do poder calorífico superior e analise imediata. Os resultados mostram que os resíduos gerados pelas espécies apresentaram boas qualidades para a geração de energia...

Residual biomass potential of commercial and pre-commercial sugarcane cultivars

Landell,Marcos Guimarães de Andrade; Scarpari,Maximiliano Salles; Xavier,Mauro Alexandre; Anjos,Ivan Antônio dos; Baptista,Antônio Sampaio; Aguiar,Cláudio Lima de; Silva,Daniel Nunes da; Bidóia,Márcio Aurélio Pitta; Brancalião,Sandro Roberto; Bres
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2013 EN
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Sugarcane (Saccharum spp.) is an efficient and sustainable alternative for energy generation compared to non-renewable sources. Currently, during the mechanized harvest process, the straw left in the field can be used in part for the second generation ethanol and increasing the electric energy production. Thus, this study aimed to provide information on the potential for residual biomass cultivars of sugarcane cropping system. This study provides the following information: yield of straw, depending on the calculated leaf area index and the number of tillers per linear meter; primary energy production of several sugarcane genotypes; contribution of dry tops and leaves; biomass yield; and evaluation of fiber, cellulose, hemicellulose and lignin. Preliminary results obtained by researchers of the State of São Paulo, Brazil, and reCviews related studies are presented. The results suggest that the production of sugarcane straw content varies according to the cultivars; the greater mass of sugarcane straw is in the top leaves and that the potential for the crude energy production of sugarcane per area unit can be increased using fiber-rich species or species that produce more straw. The straw indexes was shown to be a good indicator and allow the estimation of straw volumes generated in a sugarcane crop. The cellulose...

Crude protein and metabolizable energy levels for layers reared in hot climates

Almeida,VR; Dias,AN; Bueno,CFD; Couto,FAP; Rodrigues,PA; Nogueira,WCL; Faria Filho,DE
Fonte: Fundação APINCO de Ciência e Tecnologia Avícolas Publicador: Fundação APINCO de Ciência e Tecnologia Avícolas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2012 EN
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The objective of the present study was to evaluate the effects of different dietary crude protein (CP) and metabolizable energy (ME) levels on the performance, internal and external egg quality, and cloacal temperature of commercial layers reared in hot climate. In this trial, 100 commercial Hy-Line W-36 layers between 20 and 32 weeks of age were distributed according to a completely randomized experimental design with a 2 x 2 factorial arrangement, consisting of two CP levels (15 e 18%) and two ME contents (2700 and 3100 kcal/kg) with five replicates per treatment and 10 birds per replicate. Performance (feed intake, egg production, egg mass, and feed conversion ratio), internal (Haugh units and albumen and yolk percentage) and external (eggshell % and thickness) egg quality parameters were evaluated. Cloacal temperature was measured in two birds per replicate at 8:00 h and 13:00 h. The diet containing 2700 kcal ME/kg promoted the best performance, whereas the worse performance observed in birds fed the diet with 3100 ME/kg was partially recovered when the diet contained 18% CP. Haugh units worsened as dietary CP level increased. The other external and internal egg quality parameters were not affected by dietary CP or ME levels. The cloacal temperature of birds fed 15% CP was lower in the morning and higher in the afternoon relative to those fed 18% CP...

Protótipo de uma unidade com tri-geração de energia para utilizações remotas: aplicação de módulo secondutivo gerador termoelétrico

Santos, Ildefonso Martins dos
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Mecânica; Tecnologia de Materiais; Projetos Mecânicos; Termociências Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Mecânica; Tecnologia de Materiais; Projetos Mecânicos; Termociências
Tipo: Dissertação Formato: application/pdf
POR
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The generation for termoeletricity is characterized as a solid process of conversion of thermal energy (heat) in electric without the necessity of mobile parts. Although the conversion process is of low efficiency the system presents high degree of trustworthiness and low requisite of maintenance and durability. Its principle is based on the studies of termogeneration carried through by Thomas Seebeck in 1800. The frank development of the technologies of solid state for termoeletricity generation, the necessity of the best exploitation of the energy, also with incentive the cogeneration processes, the reduction of the ambient impact allies to the development of modules semiconductors of high efficiency, converge to the use of the thermoeletric generation through components of solid state in remote applications. The work presents the development, construction and performance evaluation of an prototype, in pilot scale, for energy tri-generation aiming at application in remote areas. The unit is composed of a gas lamp as primary source of energy, a module commercial semiconductor for thermoelectric generation and a shirt for production of the luminosity. The project of the device made compatible a headstock for adaptation in the gas lamp...

Placing the 2006/08 Commodity Price Boom into Perspective

Baffes, John; Haniotis, Tassos
Fonte: Banco Mundial Publicador: Banco Mundial
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The 2006-08 commodity price boom was one of the longest and broadest of the post-World War II period. Apart from strong and sustained economic growth, the recent boom was fueled by numerous factors, including low past investment in extractive commodities, weak dollar, fiscal expansion, and lax monetary policy in many countries, and investment fund activity. At the same time, the combination of adverse weather conditions, the diversion of some food commodities to the production of biofuels, and government policies (including export bans and prohibitive taxes) brought global stocks of many food commodities down to levels not seen since the early 1970s. This in turn accelerated the price increases that eventually led to the 2008 rally. The weakening and/or reversal of these factors coupled with the financial crisis that erupted in September 2008 and the subsequent global economic downturn, induced sharp price declines across most commodity sectors. Yet, the main price indices are still twice as high compared to their 2000 real levels...

State and Trends of the Carbon Market 2003

Lecocq, Franck; Capoor, Karan
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
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The emerging carbon market encompasses both project-based emission reduction transactions, whereby a buyer participates in the financing of a project which reduces greenhouse gases (GHGs) emissions, compared with what would have happened otherwise, and gets some of the emission reductions (ERs) thus generated in return; and, trades of GHG emission allowances allocated under existing, or incoming, cap-and-trade GHG emissions control regimes. This Review of the state and trends of the carbon market as of November 2003, based on material provided by Evolution Markets LLC, Natsource LLC and PointCarbon, and on direct interviews with market participants, suggest that: volume exchanged on the carbon market has more than doubled since 2002; buyers are governments, and public-private partnerships like the Prototype Carbon Fund; in 2003, nine out of ten tones of emission reductions originate from projects located in transition economies or developing countries; prices differ depending on the segment of the market, and on the structure of the transaction; allowance markets dominate in number of transactions, but volume exchanged remains small compared with project-based transactions; and, because of long lead time between project preparation and first "yield" of emission reductions...

Governance of Indian State Power Utilities : An Ongoing Journey

Pargal, Sheoli; Mayer, Kristy
Fonte: Washington, DC: World Bank Group Publicador: Washington, DC: World Bank Group
EN_US
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By the late 1990s, the technical and financial performance of the power sector in India had deteriorated to the point where the Government of India had to step in to bail out the state utilities, almost all of which were vertically integrated state electricity boards (SEBs). Considering that the dismal performance of state utilities reflected internal and external shortfalls in governance, the new Electricity Act of 2003 (EA 2003) mandated the unbundling and corporatization of the SEBs, along with the establishment of independent regulators. This was expected to bring about a more accountable and commercial performance culture, with concomitant results in improved utility performance. The rest of this review is organized as follows. Chapter two summarizes the institutional context and relevant developments over the past two decades. Chapter three focuses on the corporate governance agenda adopted by the government and its implementation, specifically relating to the structure and functioning of utility boards of directors. Chapter four reviews SERC regulatory governance. Chapter five analyzes the correlation between key indicators of the quality of regulatory and corporate governance and utility financial performance. And chapter six concludes.

Liberating the Power of Energy Services and ESCOs in a Liberalised Energy Market

BERTOLDI PAOLO; REZESSY Silvia; HINNELS Mark
Fonte: European Commission DG JRC Publicador: European Commission DG JRC
Tipo: Contributions to Conferences Formato: Printed
ENG
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Energy Services Companies (ESCos) could help to address barriers to energy efficiency and microgeneration, by providing information, finance, installation, operation and maintenance under a long-term contract. Three distinct types of market are identified. First, the commercial and industrial sector, using a ‘facilities management’ or ‘performance contract’ model, where the ESCo offering is most developed, and where there remains great potential. Second a community model, where decisions are taken by or on behalf of a group of customers in the same location (for example, but not exclusively, a Community Heating scheme). There is particular opportunity in new build, and in social housing. Third, a household model, where energy suppliers, contractors or equipment suppliers to existing residential customers may evolve to include energy efficiency and microgeneration. This is the hardest market for ESCos since the transaction costs of servicing millions of small (and skeptical) consumer is currently large compared to the savings. There is a well-established incumbent industry with significant barriers to new market entry for an alternative business model. The paper explores opportunities and barriers as well as policy options to promote each of the three models...

Comparison of Kinetic Study of CTMA+ Removal of Molecular Sieve Ti-MCM-41 Synthesized with Natural and Commercial Silica

Fontes,Maria do Socorro Braga; Melo,Dulce Maria de Araújo; Costa,Cintia de Castro; Braga,Renata Martins; Melo,Marcus Antonio de Freitas; Alves,José Antônio Barros Leal Reis
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
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This work aimed to determine and compare the apparent activation energy, involved in thermal decomposition of CTMA+ from the pores of Ti-MCM-41 synthesized by two different source of silica in order to evaluate their influence in the template removal. The molecular sieves Ti-MCM-41 were synthesized using rice husk ash (RHA), as alternative low cost source of silica, and commercial silica gel, obtaining two mesoporous material by hydrothermal synthesis of gel molar composition of: 1.0 CTMABr: 4.0 SiO2: X TiO2: 1.0 Na2O: 200.0 H2O. The samples were characterized to compare its properties by X-ray diffraction, IR spectroscopy, BET method and thermogravimetric analysis (TGA). The kinetic study using the model proposed by Flynn and Wall to determine the apparent activation energy for CTMA+ removal was performed using TGA data. The thermogravimetric analysis results of the material obtained from RHA confirmed intrinsic properties of mesoporous MCM-41 as the synthesized with commercial silica gel, such as high specific area, mesoporous range of pore diameter and hexagonal structure. According to the kinetics results the RHA showed similar chemical interaction to commercial silica gel, which makes it an interesting material, since it is a low cost source of natural silica from agricultural waste.

Sealing the Strait An analysis of Iran and the GCC in the Strait of Hormuz

Alexander, Shannon
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Relatório
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The Strait of Hormuz is a relatively unremarkable geographic feature, and to those unfamiliar with its commercial and strategic significance, is little more than a channel of water linking the Persian Gulf to the Indian Ocean. Yet this narrow strait is in fact much more than simply a connecting body of water. Indeed, it is a potential site for hostile military confrontation between Iran and its adversaries, namely the United States and its allies. Nearly 40 percent of all global energy supplies traverse the strait to various destinations, rendering the safety of both exports and imports vital to the stability of the global economy. Iran, lying to the north, is acutely aware of the power it yields in the strait. It has certainly made no secret of its readiness to seal the channel, particularly if a US or Israeli military attack on its nuclear facilities (suspected nuclear weapons enrichment sites) was to occur. It is uncertain what policy objective would be fulfilled by this action, given the harm Iran would incur on its own economy, and the high risk of political isolation associated with any disruption of energy exports. Nevertheless, Iran has invoked the threat of blocking the strait as its only real tool of deterrence against the feared political and ideological ambitions of the West. The Strait of Hormuz is a relatively unremarkable geographic feature...

Beyond Crisis : The Financial Performance of India's Power Sector

Khurana, Mani; Banerjee, Sudeshna Ghosh
Fonte: Washington, DC: World Bank Publicador: Washington, DC: World Bank
Tipo: Publications & Research :: Publication
ENGLISH; EN_US
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At the end of 2011, the Indian power sector found itself in financial crisis, just a decade after the 2001 bailout of state electricity boards (SEBs) by the central government. Bankrupt state power distribution utilities in several states were unable to pay their bills or repay their debts. Despite the passage of the landmark 2003 Electricity Act and implementation of a broad set of reforms over the past decade, the sector today is looking at another rescue from the center, four times larger than before. This financial rescue scheme amounts to about Rs 1.9 trillion ($42 billion) and was instigated by the nonperforming assets of the banks and other financial institutions. The Electricity Act was envisaged to create independent companies functioning on commercial principles, but they are still far away from that goal. This report presents a diagnostic of the financial and operational performance of segments in the power sector value chain between adoption of the Electricity Act, 2003, and 2011, including analysis of the factors that contributed to the recent crisis. The report focuses on efficiency and productivity...

Solid Waste Management Holistic Decision Modeling

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Economic & Sector Work :: Other Environmental Study; Economic & Sector Work
ENGLISH; EN_US
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This study provides support to the Bank's ability to conduct client dialogue on solid waste management technology selection, and will contribute to client decision-making. The goal of the study was to fully explore the use of the United States Environmental Protection Agency and the Research Triangle Institute (EPA/RTI) holistic decision model to study alternative solid waste systems in a wide array of waste management conditions, using data collected from cities selected in each region of the world. Seven cities were selected from the different regions of development countries served by the World Bank. Their data was considered to be competent, and they cooperated with the study teams. They were: Buenos Aires, Argentina; Conakry, Guinea; Shanghai, China; Kathmandu, Nepal; Lahore, Pakistan; Amman, Jordan; and Sarajevo, Bosnia and Herzegovina. These cities represented a range of economic development factors, income, commercial, and industrial activity, in addition to their different physical settings and climate conditions. The cities were selected to see how such divergent variables would affect the outcome of the modeling analysis. Each of the selected cities is one of the largest within its country. In addition to the 7 target cities from developing countries...

Estudo comparativo entre o sistema convencional de arrefecimento e o arrefecedor evaporativo para os edifícios industriais portugueses

Cruz, Diogo Araújo
Fonte: Instituto Politécnico do Porto Publicador: Instituto Politécnico do Porto
Tipo: Dissertação de Mestrado
Publicado em //2014 POR
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Em Portugal existem muitos espaços comerciais e industriais em que as necessidades térmicas de arrefecimento são muito superiores às necessidades de aquecimento devido aos ganhos internos que advêm da existência de equipamentos e da iluminação dos edifícios, assim como, da presença das pessoas. A instalação de sistemas convencionais de ar condicionado para espaços comerciais e industriais de grande dimensão está geralmente associada ao transporte de grandes caudais de ar, e consequentemente, a elevados consumos de energia primária, e também, elevados custos de investimento, de manutenção e de operação. O arrefecedor evaporativo é uma solução de climatização com elevada eficiência energética, cujo princípio de funcionamento promove a redução do consumo de energia primária nos edifícios. A metodologia utilizada baseou-se na criação de uma ferramenta informática de simulação do funcionamento de um protótipo de um arrefecedor evaporativo. Foi efetuada a modelação matemática das variáveis dinâmicas envolvidas, dos processos de transferência de calor e de massa, assim como dos balanços de energia que ocorrem no arrefecedor evaporativo. A ferramenta informática desenvolvida permite o dimensionamento do protótipo do arrefecedor evaporativo...

Directly Grown Nanostructured Electrodes for High Volumetric Energy Density Binder-Free Hybrid Supercapacitors: A Case Study of CNTs//Li4Ti5O12

Zuo, Wenhua; Wang, Chong; Li, Yuanyuan; Liu, Jinping
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 14/01/2015 EN
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Hybrid supercapacitor (HSC), which typically consists of a Li-ion battery electrode and an electric double-layer supercapacitor electrode, has been extensively investigated for large-scale applications such as hybrid electric vehicles, etc. Its application potential for thin-film downsized energy storage systems that always prefer high volumetric energy/power densities, however, has not yet been explored. Herein, as a case study, we develop an entirely binder-free HSC by using multiwalled carbon nanotube (MWCNT) network film as the cathode and Li4Ti5O12 (LTO) nanowire array as the anode and study the volumetric energy storage capability. Both the electrode materials are grown directly on carbon cloth current collector, ensuring robust mechanical/electrical contacts and flexibility. Our 3 V HSC device exhibits maximum volumetric energy density of ~4.38 mWh cm−3, much superior to those of previous supercapacitors based on thin-film electrodes fabricated directly on carbon cloth and even comparable to the commercial thin-film lithium battery. It also has volumetric power densities comparable to that of the commercial 5.5 V/100 mF supercapacitor (can be operated within 3 s) and has excellent cycling stability (~92% retention after 3000 cycles). The concept of utilizing binder-free electrodes to construct HSC for thin-film energy storage may be readily extended to other HSC electrode systems.

Flexibility of Commercial Building HVAC Fan as Ancillary Service for Smart Grid

Maasoumy, Mehdi; Ortiz, Jorge; Culler, David; Sangiovanni-Vincentelli, Alberto
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 24/11/2013
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In this paper, we model energy use in commercial buildings using empirical data captured through sMAP, a campus building data portal at UC Berkeley. We conduct at-scale experiments in a newly constructed building on campus. By modulating the supply duct static pressure (SDSP) for the main supply air duct, we induce a response on the main supply fan and determine how much ancillary power flexibility can be provided by a typical commercial building. We show that the consequent intermittent fluctuations in the air mass flow into the building does not influence the building climate in a human-noticeable way. We estimate that at least 4 GW of regulation reserve is readily available only through commercial buildings in the US. Based on predictions this value will reach to 5.6 GW in 2035. We also show how thermal slack can be leveraged to provide an ancillary service to deal with transient frequency fluctuations in the grid. We consider a simplified model of the grid power system with time varying demand and generation and present a simple control scheme to direct the ancillary service power flow from buildings to improve on the classical automatic generation control (AGC)-based approach. Simulation results are provided to show the effectiveness of the proposed methodology for enhancing grid frequency regulation.; Comment: Proceedings of Green Energy and Systems Conference 2013...

Analyzing costs and benefits of rerouting vessel traffic to open areas for offshore wind development in the mid-Atlantic United States

Samoteskul, Kateryna
Fonte: University of Delaware Publicador: University of Delaware
Tipo: Tese de Doutorado
Relevância na Pesquisa
25.9%
Firestone, Jeremy; The recent emphasis on development of offshore wind energy projects has powered the movement to evaluate distribution of current ocean activities. As wind energy development becomes more prevalent, existing users of the oceans, such as commercial shippers, will be compelled to share their historically open-access waters with these projects. Here, we demonstrate the utility of using cost-benefit analysis (CBA) framework to reduce potential spatial conflicts and assess tradeoffs between offshore wind development and commercial shipping. Specifically, we evaluate whether rerouting commercial vessel traffic farther from shore to open areas for wind development would produce net societal benefits. We focus on less than 1,500 transits by deep-draft vessels between the ports in the US Mid-Atlantic. We propose to reroute these ships by an average of 18.5 km (10 nautical miles) per trip. We estimate that over 29 years of the study, the added private and external vessel costs amount to approximately $0.2 billion (in 2012$). The net benefits of the proposed policy are approximately $14 billion (in 2012$). Considering the large societal benefits, modifying areas where vessels transit needs to be included in the portfolio of policies used to support the launch and growth of the offshore wind industry in the US.; University of Delaware...