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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.
671

Predicting the time rate of supply from a petroleum play

Kaufman, Gordon Mayer, Runggaldier, W., Livne, Zvi A. January 1979 (has links)
No description available.
672

[en] ESTIMATION OF THE LOAD FACTOR (LF) AND THE DEMAND FACTOR (DF) OF ELECTRICITY CONSUMERS VIA MEASUREMENTS AND ELECTRICAL APPLIANCES OWNERSHIP AND USAGE SURVEYS / [pt] ESTIMATIVA DO FATOR DE CARGA (FC) E FATOR DE DEMANDA (FD) DE CONSUMIDORES DE ENERGIA ELÉTRICA VIA MEDIÇÃO E PESQUISA DE POSSES E HÁBITOS

WESLEY DE CASTRO FAGUNDES 01 November 2011 (has links)
[pt] O objetivo desta dissertação é apresentar os conceitos de Fator de Carga (FC) e Fator de Demanda (FD) e verificar o quanto estas informações estão atualizadas para uso pelas concessionárias de energia elétrica. A motivação pelo estudo resultou do fato de o conhecimento e o gerenciamento desses índices proporciorem maior eficiência e segurança às instalações e equipamentos, além de permitir redução do custo da energia elétrica. A metodologia utilizada para o cálculo se baseia nos testes de Chauvenet, que permite determinar se um valor amostral (resultante de uma medição) é anômalo (outlier) em relação aos restantes valores da amostra, supondo-se que esta amostra é retirada de uma distribuição normal. Dentre os principais resultados destacam-se estimativas do Fator de Carga e Fator de Demanda, típicos para os diversos segmentos de clientes de uma empresa de distribuição de energia elétrica. Para se obter essas estimativas foi realizada uma pesquisa de campo permitindo o levantamento da potência instalada em clientes atendidos na alta e na baixa tensão. Em paralelo à pesquisa de campo, a concessionária de energia elétrica realizou medições de consumo e demanda junto a esses clientes. Como conclusão o trabalho confirma que as distribuidoras de energia elétrica não possuem acesso a um cadastro atualizado da potência instalada de seus consumidores. Faz-se necessário uma atualização mais dinâmica nas bases de dados disponíveis o que permitiria uma estimativa mais precisa dos fatores de carga e de demanda. / [en] The aim of this work discusses basic concepts associated with the load factor (LF) and demand factor (DF) and the adequacy of their use by electricity utilities. The knowledge and management of these electrical parameters is rather important, as they contribute for the improvement of the efficiency and security of the system as a whole while promoting reduction on energy costs. The method used to estimate these quantities is based on the Chauvenet statistical tests capable to detect and remove possible discontinuity on the sample data observed to follow normal distribution. The LD and DF were estimated for various clusters of similar clients of a given distributing utility. Estimations were obtained through a survey involving clients of the selected utility to capture information on the end-users and their nominal power demanded at both, the low and high voltage levels. In parallel to the survey, the utility measured and monitored the energy consumption of the clients participating in the study. As a conclusion, the study revealed that the electricity utilities do not have access to update information (stratified by segments of clients) on the electrical parameters. A dynamic scheme to make available updated information related to load factor and demand factor proved to be extremely useful and is highly recommended.
673

PEDAGOGICAL AND CULTURAL PHENOMENA OF ON-DEMAND WRITING INSTRUCTION

Bell, Deborah L. 01 May 2012 (has links)
In 1985, 66 school districts filed a suit against the Kentucky Department of Education accusing the system of inequitable spending practices. In 1990, the Supreme Court declared the entire educational program unconstitutional, resulting in the Kentucky Education Reform Act or KERA. This new reform movement brought a plethora of changes to school districts across the state including its mode of assessment. KERA introduced new avenues of measuring student progress using writing as the main vehicle to assess content and communication skills. Unfortunately, the majority of Kentucky's high schools showed little improvement in this tested area with only 34% of high schools reaching proficiency in the past twenty years of KERA's existence. In 2009, Kentucky passed into law Senate Bill 1, voiding the previous assessment but increasing the focus on on-demand writing for five grades rather than the three required by KERA. Preempting this new reform was the adoption of the Common Core Standards, which also includes a focus on writing. This consistent attention to writing assessment, and data identifying writing as a major weakness across the Commonwealth, prompted the impetus to examine four schools that achieve high scores in on-demand writing assessment. This qualitative investigation employed a case study design to research these four sites, which represented four different geographic locations in the state. Data sources included observations, interviews, document analysis, and fieldnotes to explore these schools through an interpretivist lens. The collected data were entered into qualitative research software to enable collective coding resulting in distinct categories and resulting themes. Three themes evolved in this cross-case analysis: curriculum, learning culture, and motivation. Teachers from these schools use similar classroom strategies and the learning environments reflect corresponding characteristics. Each school addressed student motivation differently, but the analogous perception of inducing intrinsic and extrinsic student engagement in writing occurred in all four schools. The implications of these results could be overwhelmingly positive as schools seek suggestions to improve writing scores. The findings from this investigation are relevant to the time and may serve as an impetus to improve writing instruction.
674

Market-based coordination for domestic demand response in low-carbon electricity grids

Elizondo-González, Sergio Iván January 2017 (has links)
Efforts towards a low carbon economy are challenging the electricity industry. On the supply-side, centralised carbon-intensive power plants are set to gradually decrease their contribution to the generation mix, whilst distributed renewable generation is to successively increase its share. On the demand-side, electricity use is expected to increase in the future due to the electrification of heating and transport. Moreover, the demand-side is to become more active allowing end-users to invest in generation and storage technologies, such as solar photovoltaics (PV) and home batteries. As a result, some network reinforcements might be needed and instrumentation at the users’ end is to be required, such as controllers and home energy management systems (HEMS). The electricity grid must balance supply and demand at all times in order to maintain technical constraints of frequency, voltage, and current; and this will become more challenging as a result of this transition. Failure to meet these constraints compromises the service and could damage the power grid assets and end-users’ appliances. Balancing generation, although responsive, is carbon-intensive and associated with inefficient asset utilisation, as these generators are mostly used during peak hours and sit idle the rest of the time. Furthermore, energy storage is a potential solution to assist the balancing problem in the presence of non-dispatchable low-carbon generators; however, it is substantially expensive to store energy in large amounts. Therefore, demand response (DR) has been envisioned as a complementary solution to increase the system’s resilience to weather-dependent, stochastic, and intermittent generation along with variable and temperature-correlated electric load. In the domestic setting, operational flexibility of some appliances, such as heaters and electric cars, can be coordinated amongst several households so as to help balance supply and demand, and reduce the need of balancing generators. Against this background, the electricity supply system requires new organisational paradigms that integrate DR effectively. Although some dynamic pricing schemes have been proposed to guide DR, such as time of use (ToU) and real-time pricing (RTP), it is still unclear how to control oscillatory massive responses (e.g., large fleet of electric cars simultaneously responding to a favourable price). Hence, this thesis proposes an alternative approach in which households proactively submit DR offers that express their preferences to their respective retailer in exchange for a discount. This research develops a computational model of domestic electricity use, and simulates appliances with operational flexibility in order to evaluate the effects and benefits of DR for both retailers and households. It provides a representation for this flexibility so that it can be integrated into specific DR offers. Retailers and households are modelled as computational agents. Furthermore, two market-based mechanisms are proposed to determine the allocation of DR offers. More specifically, a one-sided Vickrey-Clarke-Groves (VCG)-based mechanism and penalty schemes were designed for electricity retailers to coordinate their customers’ DR efforts so as to ameliorate the imbalance of their trading schedules. Similarly, a two-sided McAfee-based mechanism was designed to integrate DR offers into a multi-retailer setting in order to reduce zonal imbalances. A suitable method was developed to construct DR block offers that could be traded amongst retailers. Both mechanisms are dominant-strategy incentive-compatible and trade off a small amount of economic efficiency in order to maintain individual rationality, truthful reporting, weak budget balance and tractable computation. Moreover, privacy preserving is achieved by including computational agents from the independent system operator (ISO) as intermediaries between each retailer and its domestic customers, and amongst retailers. The theoretical properties of these mechanisms were proved using worst-case analysis, and their economic effects were evaluated in simulations based on data from a survey of UK household electricity use. In addition, forecasting methods were assessed on the end-users’ side in order to make better DR offers and avoid penalties. The results show that, under reasonable assumptions, the proposed coordination mechanisms achieve significant savings for both end-users and retailers, as they reduce the required amount of expensive balancing generation.
675

Creación y destrucción de empleos en el sector manufacturero del Perú: 2002-2007

Tello, Mario D. 10 April 2018 (has links)
Creation and destruction of jobs in Peru’s manufacturing sector: 2002-2007By way of a set of productive factors from a sample of manufacturing firms that created and destroyed jobs in Peru’s formal manufacturing sector for the period 2002-2007, this paper estimates the conditional labor demand equation under three interpretations. The results of these assessments suggest that job creation and destruction were statistically related to positive and negative changes of real output respectively. However, the rates of change of these job flows were lower than those of the real output value. On the other hand, job flows were positively associated with firms’ degrees of processing. Other minor factors associated with job flows were the size of firms and the capital-labor ratio. / Mediante una serie de factores productivos de una muestra de empresas manufactureras formales peruanas que crearon y destruyeron empleo en el periodo 2002-2007, este trabajo estima la ecuación de demanda condicional de mano de obra en sus tres interpretaciones. Los resultados de estas estimaciones señalan que la creación y destrucción de empleos estuvieron asociadas a los cambios positivos y negativos,  respectivamente, de la producción. Sin embargo, los cambios porcentuales del empleo fueron en general de menor magnitud que los respectivos de la producción.De otro lado, el nivel y la creación de empleo se incrementan con un mayor grado de procesamiento de los productos elaborados por las firmas manufactureras. El tamaño de las empresas y la intensidad de uso del capital relativo a la mano de obra inciden también, aunque con menor grado de fortaleza estadística, sobre las variaciones del empleo.
676

Determining the socio-economic value of groundwater: Franschhoek case study

Pearce, Darian January 2011 (has links)
Magister Scientiae - MSc / The Western Cape, a province of South Africa is facing increased pressure to develop new supplies of fresh water to cater for the regions rapidly growing demand. Groundwater is being explored as a possible contributor to the freshwater supply. Development of the resource has been slow despite the existence of significant potential groundwater resources in the form of several shallow primary aquifer systems and an extensive secondary aquifer formation known as the Table Mountain Group (TMG) Aquifer. This slow development may be attributed primarily to a lack of awareness amongst key stakeholders and general ignorance in the water market with regards to the potential of this resource.
677

[en] PRELIMINARY INTERVIEWS IN FAMILY PSYCHOTHERAPY: CONSTRUCTING THE CONJOINT DEMAND / [pt] ENTREVISTAS PRELIMINARES EM PSICOTERAPIA DE FAMÍLIA: CONSTRUÇÃO DA DEMANDA COMPARTILHADA

REBECA NONATO MACHADO 06 May 2010 (has links)
[pt] Dando continuidade aos estudos sobre o início do tratamento familiar, a presente pesquisa teve como objetivo investigar o período de entrevistas preliminares com famílias. Procurou-se focar a avaliação diagnóstica, assim como, as implicações da construção da demanda compartilhada e sua influência na adesão familiar ao tratamento. A demanda familiar compartilhada foi uma noção desenvolvida neste estudo, significando a motivação latente que conduziu o grupo à psicoterapia. Ou seja, corresponde aos conteúdos interpsíquicos que são ainda incompreensíveis para a família. Entende-se que no período de entrevistas seja importante problematizar a queixa inicial, centrada nos conflitos existentes com o paciente identificado. Estas intervenções iniciais visam à realização de uma transformação da posição de vítima da família, para um posicionamento conjunto responsável pela manutenção de seu sofrimento. Buscou-se também enfatizar a riqueza do uso de dispositivos diagnósticos, entendendo-os como um recurso que contextualiza as hipóteses do psicoterapeuta e promove uma ampliação na cadeia associativa da família. Nesta investigação descreveu-se a técnica Arte-Diagnóstico Familiar, a fim de difundi-la ainda mais no Brasil como um instrumento complementar à avaliação diagnóstica familiar. Para atingir os objetivos propostos, foram descritos três casos clínicos. Eles ilustraram o período de entrevistas e o trabalho de construção da demanda familiar compartilhada, cujas análises pretenderam contribuir para o enriquecimento do trabalho inicial da psicoterapia de família. / [en] Pursuing our studies about the beginning of the family treatment, the present research aimed at investigating the period of preliminary interviews with families. An effort was made to focus on the diagnostic evaluation of the family motivations to seek for psychotherapeutic help as well as on the implications of constructing the conjoint demand and its influence on the family adherence to the treatment. The conjoint family demand was a notion developed in this study, meaning the latent motivation shared by all the family members which led them, conjointly, to look for psychotherapy. In other words, it corresponds to the interpsychic contents that are still incomprehensible to the family. It is assumed that during the period of interviews it is important to raise the problematical issue of the initial complaint, focused on the existing conflicts with the identified patient. These initial interventions seek the transformation of the family’s position as victims to a conjoint positioning, responsible for the maintenance of their suffering. Special emphasis was also given to the value of using evaluation instruments, considering them as a resource that contextualizes the psychotherapist’s hypothesis and promotes an increase of the family’s associative chain. This investigation described exclusively the Family Art Evaluation in order to disseminate it even more in Brazil as a complementary instrument to the family diagnostic evaluation. To achieve the proposed objectives, three clinical cases, with different complaints and problematical issues, were described. They illustrated both the period of interviews and the work in constructing the family conjoint demand, whose analyses were intended to contribute to the enrichment of the initial work of the family psychotherapy.
678

Restrições ao crescimento econômico no Brasil : evidências para o período 1990-2013

Araújo, Elisangela Luzia January 2015 (has links)
O objetivo do presente trabalho foi analisar a trajetória de desaceleração, vivenciada pela economia brasileira, a partir dos anos 1990 até 2013, com o foco nas restrições impostas ao crescimento econômico – do lado da oferta, de demanda e institucionais – e suas implicações fundamentais. Apoiado nas principais interpretações teóricas e também na literatura empírica sobre a insuficiência do crescimento econômico no Brasil, elaborou-se uma investigação teórico-histórico-empírica, a fim de identificar os principais obstáculos existentes, investigando-se o seu papel na determinação da trajetória verificada nas últimas décadas. O procedimento metodológico envolveu três etapas. Na primeira, buscou-se explicitar um aparato teórico-conceitual, a partir de uma resenha literária sobre a temática do crescimento econômico, com ênfase nos fatores que podem restringir o referido processo, de acordo com três abordagens principais: a economia tradicional (ortodoxa), a vertente keynesiana-neoestruturalista e a visão da economia institucional. A segunda etapa realizou uma discussão reflexiva que identificou o contexto do surgimento e a evolução dos obstáculos relevantes ao crescimento sustentado no Brasil. Na terceira etapa, desenvolveu-se uma análise econométrica que se dividiu em duas partes: a primeira utilizou a metodologia para dados em painéis, para inferir as correlações entre algumas variáveis selecionadas e o crescimento econômico em um conjunto de 67 países entre 1990 e 2013, e a segunda realizou uma análise de séries temporais, visando avaliar a relação entre as restrições ao crescimento e a trajetória de baixo dinamismo, verificada a partir dos anos 1990. Os principais resultados da pesquisa sugeriram a existência de uma relação forte e direta entre a presença das restrições – de oferta, de demanda e institucionais – e o desempenho pífio da economia brasileira, que ocorreu em razão da deterioração dos canais fundamentais para o crescimento sustentado: o investimento, a produtividade e o setor externo, justificando o quadro de semiestagnação que caracterizou as últimas décadas. / The objective of this study was to analyze the trend of deceleration experienced by the Brazilian economy, from the years 1990 to 2013 with a focus on restrictions on economic growth - on the supply side, demand and institutional ones - and its fundamental implications. Supported by the main theoretical interpretations and also by the empirical literature on the failure of economic growth in Brazil, we elaborated a theoretical and historical-empirical research to identify the main obstacles, investigating its role in determining the trend observed in recent decades. The methodological procedure involved three steps. At first, we tried to clarify a theoretical and conceptual apparatus, through a literature review on the economic growth, with emphasis on factors that may restrict this process, according to three main approaches: the traditional (Orthodox) economy, the Keynesian-neoestruturalist vision and the institutional economics. The second stage held a reflective discussion which identified the emergence of the context and the evolution of relevant obstacles to the resumption of economic growth in Brazil. In the third stage, we dedicated to an econometric analysis was divided into two parts developed: the first used the methodology for data panels aiming to infer some correlations between selected variables and economic growth in a set of 67 countries between 1990 and 2013 and, the second, we conducted a time series analysis to evaluate the relationship between the constraints to growth and the trajectory of low dynamism observed from the early 1990. The main results of this study suggested the existence of a strong and direct relationship between the presence of restrictions – of the supply and demand side and institutional ones - and the weak performance of the Brazilian economy, which took place due to the deterioration of basic channels for sustained growth: investment, productivity and the external sector, justifying the semi-stagnation framework that characterized the last decades.
679

ASSESSING THE RELIABILITY OF ROOFTOP RAINWATER HARVESTING FOR DOMESTIC USE IN WESTERN KENYA

Mundia, Clara 01 May 2010 (has links)
In many developing countries, the stress of rapidly growing populations, mismanagement of resources and changing climate has created a burden on already compromised water resources. In Africa, where a significant proportion of the population is without access to improved water source, the urgency for clean available water sources to sustain healthy and productive human and natural populations has become a priority. As a water scarce country, Kenya has seen an increased investment in rainwater harvesting (RWH) projects to harness the vastly untapped rainwater resource, particularly in rural areas. Most of RWH literature is centered on the potential and implementation of rainwater harvesting systems, however not much focus has been placed on examining the demand satisfaction of these systems. This study investigates the reliability of rooftop rainwater harvesting (RRWH) as a key priority source of water supply for domestic use in three towns in Western Kenya: Kisumu, Nakuru and Lodwar. This was done using two approaches (1) the fraction of time water was available and (2) the fraction of time that a minimum demand was met, with acceptable reliability of 0.95 or higher. Actual rainfall data and RRWH parameters were used to produce supply/demand simulations of the system under Constant-Demand and Responsive-Demand scenarios over ten years. It was observed that all towns achieved acceptable reliability values for RRWH in terms of water availability however Lodwar only achieved demand satisfaction below 0.95. This study concluded that though RRWH cannot satisfy the minimum demand requirement through all days of the year, it is more than able to provide an alternative water supply for the domestic household in periods of long dry spells or when primary water source are inadequate.
680

Sustainable Water Usage and Surface Runoff Management in Lagos, Nigeria.

Kandissounon, Gilles-Arnaud 01 May 2018 (has links)
The exponential growth of the world population led by the geographic expansion of urban areas in developing countries has put massive pressure on natural resources especially land and water. Water supply and water scarcity remain one of the major challenges facing the industrializing world. The United Nations forecast further increase in population which, in the absence of management and policies, will inevitably put more resources at risk. Changing climatic conditions causing more frequent and intense rainfall will also affect water management systems in the vulnerable urban areas of developing countries. The goal of this study was twofold; first analyze the patterns of water consumption in the rapidly growing city of Lagos, Nigeria and use them in a System Dynamics (SD) model to make projections about future demand. The second part used remote sensing to quantify the contribution of extensive land use/cover change to urban flooding. Land use/cover dynamics over the past decade was analyzed using satellite imagery provided by Landsat Thematic Mapping (TM). Unsupervised classification was performed with false color composite using the Iterative Self-Organizing Data Analysis (ISODATA) technique in a Geographic Information Systems (GIS). The study area was divided into four different land use types during image classification: bare land, built-up area, water bodies, and vegetation. For water demand, two different scenarios of population growth including 5.5% and 2.75 % annual increase were considered. The results showed that water demand dropped by 67% of its current value when losses in distribution were reduced by 20% and population annual growth rate kept at 2.75% over the study period. Bare land and water bodies lost 1.31% and 1.61% of their current area respectively while built-up area grew by 1.11%. These changes in land use/cover changes led to a 64% increase in average surface runoff, mostly attributable to increasing surface imperviousness and the absence of an adequate urban drainage system. This paper intends to assist the authorities of the city of Lagos who adopted a master plan in 2010 as a road map to reduce to city’s vulnerability to flooding and close the gap between water demand and water supply by 2050.

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