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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Essays on inheritance, small businesses and energy consumption

Escobar, Sebastian January 2017 (has links)
Essay 1: People’s planning to evade the inheritance tax curtails its merits. However, the extent of planning remains a matter of argument. According to popular belief, it is widespread, but few estimates have been presented. This study estimates the extent of estate size under-reporting, a form of inheritance tax planning, using the repeal of the Swedish tax on spousal bequests, in 2004, and a regression discontinuity design. The results show that, on average, estate sizes were 17 percent lower, and the share of estates that completely escaped tax payments was 26 percent larger due to under-reporting. As a consequence, government revenues from the tax were only half of what they would have been without under-reporting. Moreover, preferences and means for under-reporting were not only prevalent among the wealthy, but also among those receiving relatively small inheritances. The study contributes to a growing literature on tax avoidance and evasion by estimating the extent of estate size under-reporting, its effect on government revenues and by showing that it was widespread in the population. / Essay 2: There is an ongoing debate about whether or not inheritance and estate taxes are effective in raising revenues and in contributing to a more equal society. The different views on transfer taxes are largely dependent on beliefs about whether people plan their wealth to avoid these taxes. In this paper, we follow Kopczuk (2007) and study people's planning response to the onset of terminal illness. An extension of Kopczuk’s work is that we can effectively control for responses in wealth caused by terminal illness but unrelated to tax planning. We do this by exploiting a tax reform in Sweden that removed the incentives for people to plan their estates to avoid inheritance taxation. We find some evidence of long-term terminal illness inducing responses consistent with tax planning, but that these are not widespread or efficient enough to reduce the overall tax burden in the study population. Our results, similarly to those of Kopczuk, show that people appear to postpone some decisions about their estates until shortly before death. / Essay 3: Small businesses form an essential part of all economies, making it necessary to understand the conditions under which they operate. This paper contributes to that understanding by studying how survival, income and profits of small businesses change when their owners receive inheritances. Using a difference-in-differences strategy and Swedish registry data on small businesses and estate reports, it is shown that survival rates increase with almost three percentage points when the owners receive inheritances of, on average, SEK 275,000. However, the profits of the surviving small businesses and the income of their owners do not increase, indicating that the inheritance did not increase survival by making investments possible, investments to increase profits and income, but by enabling small business owners of lower ability to subsist. The study contributes to the literature on the conditions for small businesses by providing causal evidence on the effect of increased access to capital among existing businesses. It thereby complements the rich literature on the role of capital for small business start-ups. / Essay 4: This article shows that a simple monetary incentive can dramatically reduce electric energy consumption (EEC) in the residential sector and simultaneously achieve a more desirable allocation of EEC costs. The analyses are based on data from a policy experiment conducted in 2011 and 2012 by a private housing company in about 1,800 apartments. Roughly 800 of the tenants (treatment group) were subject to a change from having unlimited EEC included in their rent to having to pay the market price for their own EEC. This change was achieved by installing EEC meters in each apartment. Tenants in the other 1,000 apartments (control group) experienced no policy change and were subject to apartment-level billing and metering during the entire study period. Using a quasiexperimental research design and daily data on EEC from 2007 to 2015, we estimate that apartment-level billing and metering permanently reduce EEC by about 25%. Moreover, we show that households reduce EEC immediately after being informed that they will be billed for EEC, the reduction is larger when the production cost is higher, and the reduction in EEC comes almost exclusively from households with very high EEC before the policy change. Finally, we show that apartment-level billing and metering are cost-effective, with a cost per reduced kilowatt hour of US$0.01, and for each invested dollar, the social value of reductions in air pollution, including CO2 emissions, is $2.
132

Micro-redes elétricas: estado da arte e contribuição para o dimensionamento, aplicação e comercialização da energia produzida. / Microgrid systems: a study on the state-of-the-art and contribution for the dimensioning, application and trading of the power produced.

Del Carpio Huayllas, Tesoro Elena 16 June 2015 (has links)
As conseqüências e repercussões do recente blecaute de grande escala ocorrido no Brasil em 2009, que afetou as regiões Sudeste, Sul, Centro-Oeste e Nordeste além do Paraguai todo; assim como aqueles que afetaram a região do Norte e Nordeste dos Estados Unidos (2003) e toda Itália, também em 2003, mostraram mais uma vez que na atualidade a sociedade tem uma dependência quase total da energia elétrica. Em todos os casos, a falta de energia elétrica atingiu de forma significativa vários setores da economia, ao passo que sistemas de transporte elétrico, indústrias e hospitais sem sistemas de geração emergencial, instituições acadêmicas, iluminação pública e residencial e, inclusive, sistemas de comunicação, ficaram praticamente inoperantes. Após esses eventos, houve uma busca por algumas alternativas que ofereçam maior confiabilidade no fornecimento de energia elétrica ou, pelo menos, alternativas que ajudem a minimizar o seu impacto. O estabelecimento de sistemas baseados em micro-redes elétricas mostrou-se como uma alternativa que poderia ser utilizada para tal finalidade, de tal forma que não apenas cargas críticas, mas também boa parte das atividades mencionadas poderia continuar operando durante períodos de contingência. Por outro lado, o conceito das micro-redes elétricas tem ganho recentemente maior atenção em virtude da crescente penetração de fontes de geração distribuída e dos incentivos providos pelos governos para promover a geração de energia através de fontes renováveis como por exemplo a energia eólica, solar, biomassa, hidrelétrica, e outras. Nos mais diversos países do mundo, atualmente, populações assentadas em regiões remotas utilizam esquemas baseados em micro-redes elétricas para o suprimento de energia elétrica. Assim, neste trabalho serão apresentados os resultados referentes ao estudo da tecnologia das micro-redes elétricas, especificamente o seu desempenho diante de condições operativas como o modo de operação ilhado e o modo conectado com a rede elétrica. Particularmente, a transição para o modo de operação ilhado demandou um estudo, através das simulações, mais dedicado. No que se refere à negociação da energia entre a micro-rede e a rede principal, quando da disponibilidade de energia excedente nos períodos de carga reduzida na micro-rede, será apresentada uma análise crítica dos possíveis métodos de tarifação, os quais até agora são apenas utilizados na forma de incentivos governamentais. Será também apresentada uma análise referente à viabilidade econômica de micro-redes, já que para que estas tenham atratividade econômica, os custos de aquisição de equipamentos e operação devem também ser competitivos. / After the occurrence of some major blackouts like the one that affected the Northern and Northeastern part of the United States in 2003, the one that affected the Southeast, Midwest and Northeastern part of Brazil including Paraguay, in 2009; and the blackout that affected the whole Italy in 2003, to mention a few a few of them, there was a rush for seeking some alternatives to deal with such events or at least find out feasible solutions that can contribute to diminish their impact. The lack of electric power, for whatever reason it was, unveiled one common fact, our modern society is so dependent on electricity that during the blackouts areas like the electrical transport system, financing activity, academic institutions, industries, health centers with no emergency or standby generation, public and residential lighting and even some communication systems failed to operate. The establishment of microgrid systems proved to be an alternative that could be used for this purpose; thus, not only critical loads, but also some of the activities mentioned earlier on could continue their operation during such emergency periods. In addition, the concept of micro-grid systems has recently gained particular attention due to the increasing penetration of distributed generation and also due to the incentives provided by the governments to promote the generation of electricity from renewable sources such as wind power, solar, biomass, small hydroelectric schemes, etc. At present, countless settlements located in remote areas worldwide use microgrid systems to generate and distribute electricity. In this work, the results related to the microgrid technology, specifically its performance towards system conditions such as the islanding mode and grid connected mode of operation will be presented. Particularly, the transition to the islanded mode of operation demanded a more dedicated study during the simulations performed. As for the energy trading between the microgrid and the utility, which can occur when the microgrid generators are lightly loaded, it will be presented a critical analysis about the possible tariff methods to be applied. Such tariffs are so far only applied in the form of government subsidies to promote the use of renewable energy sources. Additionally, an analysis of a microgrid economic feasibility to show how competitive or complimentary this technology is with the utility will be presented herein.
133

Medidor inteligente de energia elétrica embarcado em FPGA /

De Oro Arenas, Luis January 2019 (has links)
Orientador: Carlos Alberto Canesin / Resumo: Nesta tese é apresentado o desenvolvimento inédito de um equipamento de medição de parâmetros de qualidade de energia elétrica embarcado em um dispositivo FPGA, incorporando funcionalidades que o caraterizam como medidor inteligente. Dessa forma, obteve-se uma plataforma capaz de realizar monitoramento e verificação, em tempo real, do comportamento de sistemas de energia elétrica quando estes operam em condições de desequilíbrio, desbalanços, assimetria nos ângulos de defasagem e presença de componentes harmônicas, impostas pelo comportamento das cargas e/ou pelas tensões de alimentação do sistema. Para isso, foram empregadas as metodologias de cálculos de potência definidas pelo padrão IEEE 1459-2010 e a Teoria da Potência Conservativa. Técnicas de processamento digital de sinais são aplicadas para a descrição dos módulos de sincronismo e janelamento, baseados na norma NBR-IEC-61000-4-30:2010, assim como filtros digitais e deslocadores de fase adaptativos para a extração das componentes fundamentais e componentes fundamentais de sequência positiva. Adicionalmente, são detalhados todos os estágios relacionados com o condicionamento e amostragem dos sinais elétricos, cálculos de potência, cálculo de harmônicos, interface de usuário, acesso aos dados e comando para desconexão/religamento de cargas remotas. Os resultados experimentais obtidos em um sistema trifásico a 4 fios, para diferentes cenários de operação, incluindo a presença de elementos de geração distribuída, evidenci... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this thesis, the development of a novel power quality equipment embedded in an FPGA device, incorporating smart-metering features, is presented. Thus, a platform capable of real-time monitoring and verification of power systems operating under sinusoidal, non-sinusoidal, balanced and / or unbalanced conditions, was obtained. For this purpose, power calculation methods defined by both the IEEE 1459-2010 standard and the Conservative Power Theory (CPT) are reviewed and implemented. Based on NBR-IEC-61000-4-30: 2010 standards, digital signal processing techniques for the synchronization and windowing tasks, as well as, adaptive digital filters and adaptive phase shifters for obtaining the extraction of fundamental components as well as the positive-sequence fundamental components, are applied. Likewise, the complete developed stages regarding conditioning and sampling of electrical signals, power calculations, harmonic component calculations, graphical user interface, remote data access, and disconnection/reconnection commands for remote loads, are detailed. The experimental results obtained from a three-phase 4-wire system, under several operations scenarios, including the presence of distributed generation (DG) elements, highlight the advantages of the implemented methodologies, when compared with commercial power quality analyzers, which use traditional definitions of power quantities. / Doutor
134

Disaggregation of Electrical Appliances using Non-Intrusive Load Monitoring / Classification des équipements électriques par le monitoring non-intrusif des charges

Bier, Thomas 17 December 2014 (has links)
Cette thèse présente une méthode pour désagréger les appareils électriques dans le profil des bâtiments résidentiels de charge. Au cours des dernières années, la surveillance de l’énergie a obtenu beaucoup de popularité dans un environnement privé et industriel. Avec des algorithmes de la désagrégation, les données mesurées à partir de soi-disant compteurs intelligents peuvent être utilisés pour fournir de plus amples informations de la consommation d’énergie. Une méthode pour recevoir ces données est appelé non-intrusifs charge identification. La majeure partie de la thèse peut être divisée en trois parties. Dans un premier temps, un système de mesure propre a été développé et vérifié. Avec ce système, les ensembles de données réelles peuvent être générés pour le développement et la vérification des algorithmes de désagrégation. La deuxième partie décrit le développement d’un détecteur de flanc. Différentes méthodes sont présentées et évaluées, avec lequel les temps de commutation des appareils peuvent être détectés dans le profil de la charge. La dernière partie décrit un procédé de classification. Différents critères sont utilisés pour la classification. Le classificateur reconnaît et étiquette les appareils individuels de la courbe de charge. Pour les classifications différentes structures de réseaux de neurones artificiels sont comparés. / This thesis presents a method to disaggregate electrical appliances in the load profile of residential buildings. In recent years, energy monitoring has obtained significantly popularity in private and industrial environment. With algorithms of the disaggregation, the measured data from so-called smart meters can be used to provide more information of the energy usage. One method to receive these data is called non-intrusive appliance load monitoring.The main part of the thesis can be divided into three parts. At first, an own measurement system was developed and verified. With that system, real data sets can be generated for the development and verification of the disaggregation algorithms. The second part describes the development of an event detector. Different methods are presented and evaluated, with which the switching times of the appliances can be detected in the load profile. The last part describes a classification method. Different features are used for the classification. The classifier recognizes and labels the individual appliances in the load profile. For the classification different structures of artificial neural network (ANN) are compared.
135

Development of System-Based Methodology to Support Ramp Metering Deployment Decisions

Fartash, Homa 07 November 2017 (has links)
Ramp metering is an effective management strategy, which helps to keep traffic density below the critical value, preventing breakdowns and thus maintaining the full capacity of the freeway. Warrants for ramp metering installation have been developed by a number of states around the nation. These warrants are generally simple and are based on the traffic, geometry, and safety conditions in the immediate vicinity of each ramp (local conditions). However, advanced applications of ramp metering utilize system-based metering algorithms that involve metering a number of on-ramps to address system bottleneck locations. These algorithms have been proven to perform better compared to local ramp metering algorithms. This has created a disconnection between existing agency metering warrants to install the meters and the subsequent management and operations of the ramp metering. Moreover, the existing local warrants only consider recurrent conditions to justify ramp metering installation with no consideration of the benefits of metering during non-recurrent events such as incidents and adverse weather. This dissertation proposed a methodology to identify the ramps to meter based on system-wide recurrent and non-recurrent traffic conditions. The methodology incorporates the stochastic nature of the demand and capacity and the impacts of incidents and weather using Monte Carlo simulation and a ramp selection procedure based on a linear programming formulation. The results of the Monte Carlo simulation are demand and capacity values that are used as inputs to the linear programming formulation to identify the ramps to be metered for each of the Monte Carlo experiments. This method allows the identification of the minimum number of ramps that need to be metered to keep the flows below capacities on the freeway mainline segment, while keeping the on-ramp queues from spilling back to the upstream arterial street segments. The methodology can be used in conjunction with the existing local warrants to identify the ramps that need to be metered. In addition, it can be used in benefit-cost analyses of ramp metering deployments and associated decisions, such as which ramps to meter and when to activate in real-time. The methodology is extended to address incidents and rainfall events, which result in non-recurrent congestion. For this purpose, the impacts of non-recurrent events on capacity and demand distributions are incorporated in the methodology.
136

System Integration of PV/T Collectors in Solar Cooling Systems

Ghaghazanian, Arash January 2015 (has links)
The demand for cooling and air-conditioning of building is increasingly ever growing. This increase is mostly due to population and economic growth in developing countries, and also desire for a higher quality of thermal comfort. Increase in the use of conventional cooling systems results in larger carbon footprint and more greenhouse gases considering their higher electricity consumption, and it occasionally creates peaks in electricity demand from power supply grid. Solar energy as a renewable energy source is an alternative to drive the cooling machines since the cooling load is generally high when solar radiation is high. This thesis examines the performance of PV/T solar collector manufactured by Solarus company in a solar cooling system for an office building in Dubai, New Delhi, Los Angeles and Cape Town. The study is carried out by analyzing climate data and the requirements for thermal comfort in office buildings. Cooling systems strongly depend on weather conditions and local climate. Cooling load of buildings depend on many parameters such as ambient temperature, indoor comfort temperature, solar gain to the building and internal gains including; number of occupant and electrical devices. The simulations were carried out by selecting a suitable thermally driven chiller and modeling it with PV/T solar collector in Polysun software. Fractional primary energy saving and solar fraction were introduced as key figures of the project to evaluate the performance of cooling system. Several parametric studies and simulations were determined according to PV/T aperture area and hot water storage tank volume. The fractional primary energy saving analysis revealed that thermally driven chillers, particularly adsorption chillers are not suitable to be utilizing in small size of solar cooling systems in hot and tropic climates such as Dubai and New Delhi. Adsorption chillers require more thermal energy to meet the cooling load in hot and dry climates. The adsorption chillers operate in their full capacity and in higher coefficient of performance when they run in a moderate climate since they can properly reject the exhaust heat. The simulation results also indicated that PV/T solar collector have higher efficiency in warmer climates, however it requires a larger size of PV/T collectors to supply the thermally driven chillers for providing cooling in hot climates. Therefore using an electrical chiller as backup gives much better results in terms of primary energy savings, since PV/T electrical production also can be used for backup electrical chiller in a net metering mechanism.
137

AMI創新政策關鍵因素之權重評估 / Weighting Assessment on Key Factors of Advanced Metering Infrastructure Innovation Policy

梁玉琦, Liang, Yu Chi Unknown Date (has links)
如何永續發展已成為人類面臨的重大議題,依據先進國外之經驗,透過智慧電網之相關技術,可以有效的提升能源效率與達成節能減碳之目的。在國外建置智慧電網的過程中,往往從先進讀表基礎建設(Advanced Metering Infrastructure, AMI)切入,AMI對往後智慧電網的延伸發展有很大的影響。 因此,本研究旨在探討我國未來發展AMI創新政策之關鍵因素和其優先排序。首先藉由蒐集次級資料瞭解主要先進國家的AMI相關發展經驗,以及目前我國AMI的發展現況,再透過文獻探討國家創新政策,並以Rothwell &Zegveld之國家創新政策理論作為基礎架構,建立層級結構,運用模糊層級分析法(Fuzzy Analytic Hierarchy Process, FAHP ),針對國內AMI之相關產官學人員進行專家問卷調查,並整理出各項政策因素的權重排序,求出影響台灣發展AMI之創新政策關鍵因素。 從本研究實證結果顯示主層級之三項政策構面中相對權重最重的是「環境面」,在次層級十二項政策工具中,「公共服務」、「資訊服務」、「法規管制」的相對總權重最重,其為目前台灣發展AMI創新政策中最急需政府優先考量的關鍵因素。 / The sustainable development has become major issue for human. According to the experience of foreign advanced countries, it can achieve the purpose effectively of improving energy efficiency and reducing carbon emissions through the related technologies of smart grid. In the process of building smart grid abroad, it often cuts into the Advanced Metering Infrastructure (AMI). AMI has a great influence on the future extending development of the smart grid. Therefore, the study explores the key factors and precedence of AMI innovation policy in future development of our country. First, understanding the relative development experience of AMI in major advanced countries through collecting the secondary data and the current development situation of AMI in our country. Second, exploring country innovation policy through literature review, and taking theory of Rothwell & Zegveld as infrastructure to build up hierarchical structure, and using FAHP (Fuzzy Analytic Hierarchy Process) method to conduct experts survey for relative persons of industry - government - academy of domestic AMI. Then, collating the sort weights for various policy factors. Finally, finding out key factors that affect development of Taiwan’s AMI innovation policy. From the empirical results of the research shows that the most important relative weights in three main policy dimensions of the hierarchy is the “environmental surface”. The relative total weights of “public service”, “information service” ,“regulation control” and “political strategic policies” are the highest among twelve policies. They are key factor of most urgent priority for government to consider among developing AMI innovation policies in current Taiwan.
138

Bridging the divide between resource management and everyday life: smart metering, comfort and cleanliness

Strengers, Yolande Amy-Adeline, Yolande.strengers@rmit.edu.au January 2010 (has links)
Smart metering residential demand management programs, such as consumption feedback, variable pricing regimes and the remote control of appliances, are being used to respond to the resource management problems of peak electricity demand, climate change and water shortages. Like other demand management programs, these strategies fail to account for (and respond to) the reasons why people consume resources in their homes, namely to carry out everyday practices such as bathing, laundering, heating and cooling. In particular, comfort and cleanliness practices together constitute most of Australia's potable water consumption in urban centres, and represent most of household energy consumption. In addition, new household cooling practices involving air-conditioning appliances are the major contributor to the nation's rising peak electricity demand, which overloads the electricity system on hot days, costing consumers millions of dollars each year. The oversight of comf ort and cleanliness practices in smart metering demand management programs is concerning because these practices are continuing to shift and change, often in more resource-consuming directions, potentially negating the resource savings achieved through demand management programs. This thesis aims to bridge the problematic divide between the policies and strategies of demand managers, and the day-to-day practices which constitute everyday life. Using the empirical 'hook' of smart metering demand management programs and the everyday practices of comfort and cleanliness, this thesis develops a practice-based conceptual framework to study, understand and analyse these practices and the ways in which smart metering demand management programs reconfigure or further entrench them. A series of qualitative methods were employed in studying 65 households across four research groups, focusing specifically on the household practices of heating, cooling, bathing, laundering, toilet flushing and house cleaning. In addition, 27 interviews were conducted with smart metering industry stakeholders involved or implicated in delivering demand management strategies. Together, these lines of inquiry are used to analyse householders' existing and changing comfort and cleanliness practices, the role of several smart metering demand management strategies in reconfiguring these practices, and potential avenues and opportunities for further practice change in less resource-intensive directions. In particular, this thesis highlights the inherent contradictions and problems in accounting for everyday practices within the dominant demand management paradigm, and offers an alternative paradigm termed the co-management of everyday practices. The thesis concludes by briefly identifying the ways in which smart metering could potentially constrain or catalyse a transition towards this new paradigm.
139

Avaliação do sistema de medição individualizada de água em prédios populares situados na cidade do Salvador-Bahia

Silva, Sérgio Ricardo dos Santos January 2010 (has links)
168f. / Submitted by Suelen Reis (suziy.ellen@gmail.com) on 2013-04-09T17:35:05Z No. of bitstreams: 1 Dissert Sergio Ricardo.pdf: 2836987 bytes, checksum: 43815c6755b861d585a7bab20e42a98d (MD5) / Approved for entry into archive by Rodrigo Meirelles(rodrigomei@ufba.br) on 2013-04-09T17:35:55Z (GMT) No. of bitstreams: 1 Dissert Sergio Ricardo.pdf: 2836987 bytes, checksum: 43815c6755b861d585a7bab20e42a98d (MD5) / Made available in DSpace on 2013-04-09T17:35:55Z (GMT). No. of bitstreams: 1 Dissert Sergio Ricardo.pdf: 2836987 bytes, checksum: 43815c6755b861d585a7bab20e42a98d (MD5) Previous issue date: 2010 / O presente trabalho tem como seu principal objetivo avaliar os resultados alcançados com a implantação do sistema de medição individualizada de água em prédios populares abastecidos pela Empresa Baiana de Águas e Saneamento e que anteriormente possuíam medição coletiva.Quinze prédios situados na cidade do Salvador, Estado da Bahia, fizeram parte deste estudo.O método usado para a análise envolveu três aspectos: primeiro, a avaliação do padrão de consumo de água após implantação do sistema de hidrometração individualizada. A partir dos registros de consumos obtidos no Sistema Comercial da Embasa com o histórico de consumos referentes aos 24 meses que imediatamente antecederam à individualização da medição de água e aos 24 meses que a sucederam, o estudo constatou que o Indicador de Consumo Mensal no período com medição coletiva era equivalente a 18m3 por apartamento e passou para a média de 14m3 por apartamento após a hidrometração individualizada. O segundo aspecto foi a avaliação econômica da concepção de projeto adotada pelos prédios populares de Salvador, baseada em dois fatores: o custo necessário para execução da obra de adaptação hidráulica e a expectativa de ganho financeiro nas contas de água e esgoto decorrente da redução do consumo médio de água após utilização dessa nova forma de medição. O resultado mostrou que existe viabilidade financeira para essa tipologia de edificação considerando que o tempo de retorno do investimento foi inferior a três anos e a rentabilidade a partir desse período foi superior a da caderneta de poupança. O terceiro aspecto foi a avaliação da percepção do usuário sobre esse sistema de medição a partir de informações colhidas através de uma pesquisa de opinião realizada com 32 moradores dos quinze prédios, nos meses de novembro e dezembro de 2009, por meio de visitas no local. O estudo também fez uma comparação dos resultados obtidos nesta pesquisa de opinião como os resultados de outra feita anteriormente em prédios populares com medição individualizada situados em bairros do subúrbio da cidade.Este estudo verificou que com a mudança do critério de medição, considerando-se os dois anos com medição coletiva e o mesmo período com medição individualizada, houve um impacto de redução de 22% no consumo dos apartamentos dos prédios estudados, para um intervalo de confiança (IC) de 95%. A pesquisa de opinião realizada constatou um alto nível de aceitação dos condôminos ao novo sistema de medição, que alcançou 95,2%. / Salvador
140

Avaliação da qualidade de concretos produzidos em centrais dosadoras, misturados em caminhão betoneira e de concretos produzidos em centrais misturadoras / Evalution of quality of concrete produced in metering plant mixes in truck mixer and concret produced in mixed plant

BORGES, Michelly Lorena 14 December 2009 (has links)
Made available in DSpace on 2014-07-29T15:03:31Z (GMT). No. of bitstreams: 1 Dissertacao Michelly L Borges 2009.pdf: 835129 bytes, checksum: 13f31a796619274490f950cf6ef9d999 (MD5) Previous issue date: 2009-12-14 / Due to the small number of studies about the process of production of the concrete dosed in central, as regards the type of employed mixture, this inquiry looked to contribute to the assessment of quality of concrete produced in mixing plant and metering plant. The principal objective of the work was checking if the form of mixing of the concrete can affect your characteristics in hardened state (compressive strength), for that, there was compared the quality of the concrete produced in metering plant and mixed in truck mixer in relation to the mixing plant. As the sample was taken a work, where they had installed a metering plant and a mixing plant, which together produced 300.000 m³ of concrete with the same materials. Inside the proposed objective, also were quantified statistically the existent types of concrete in the same truck mixer, using as the parameter the compressive strength of concrete produced in the metering plant. In the end, it was possible to conclude that the mixing plant produce a concrete of better quality with a less standard deviation than the metering plant. Was also observed a significant variability inside the truck mixer, which made the division of the concrete possible in five group, with different resistances' / Em razão do pouco número de estudos relacionados ao processo de produção do concreto dosado em central, no que tange ao tipo de mistura empregada, esta pesquisa busca contribuir com a avaliação da qualidade de concretos produzidos em centrais misturadoras e centrais dosadoras. O objetivo principal do trabalho foi o de verificar se a forma de mistura do concreto pode afetar suas características no estado endurecido (resistência à compressão), para isso, foi comparada a qualidade do concreto produzido em central dosadora e misturado em caminhão betoneira em relação aos produzidos em central misturadora. Como amostra tomou-se uma obra, onde havia instalada uma central dosadora e uma central misturadora, que juntas produziram 300.000 m³ de concreto a partir dos mesmos materiais. Ainda dentro do objetivo proposto, foram também quantificados estatisticamente os tipos de concreto existentes em um mesmo caminhão betoneira, produzidos na central dosadora e tendo como parâmetro a resistência à compressão. Ao final, foi possível concluir que as centrais misturadoras produzem um concreto de melhor qualidade com um menor desvio padrão do que as dosadoras. Foi observada também uma variabilidade significativa dentro do caminhão betoneira, o que tornou possível a divisão do concreto em cinco grupos, com resistências distintas.

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