• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3134
  • 1727
  • 715
  • 611
  • 389
  • 363
  • 140
  • 139
  • 123
  • 121
  • 117
  • 108
  • 76
  • 56
  • 44
  • Tagged with
  • 8988
  • 2152
  • 1289
  • 973
  • 825
  • 799
  • 564
  • 483
  • 464
  • 456
  • 451
  • 421
  • 390
  • 384
  • 368
  • 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.
101

Análise da eficiência energética e da viabilidade dos ciclos de absorção na frigorificação de cargas / Analysis of energy efficiency and viability of the absorption refrigeration cycle load

Ari Ferreira de Abreu 06 July 1994 (has links)
Este trabalho aborda a problemática do transporte de carga frigorificada, sob a ótica da eficiência energética da unidade frigorífica. São propostas alternativas para conservação de alimentos, independentemente do frio. Embora incapazes de substituir totalmente o frio, podem ser uma alternativa em vários casos. É analisada a tecnologia de frigorificação atualmente empregada, enfocando custos do sistema, eficiência energética e efeitos da atual tecnologia sobre o meio ambiente. É desenvolvido o projeto preliminar de uma unidade de refrigeração por absorção, que é analisado comparativamente com as unidades por compressão a vapor. Este estudo mostra que o sistema de refrigeração por absorção pode ser viável em muitas aplicações onde não se dispõe de energia térmica ou mecânica. / This study analyses refrigerated freigth transportation, under the scope of refrigeration energy effeciency. There are several alternatives for food conservation, independently of refrigeration. These existing technologies are not capable of completely replacing refrigeration, but they could be utilized in many cases. The refrigeration techonology currently used is analysed, focusing on system costs, energy efficiency and environmental impacts. A preliminary design of an absoption system was done and an analysis was performed comparating it with the compression units. Conclusive analysis of the system will depend of the evaluation of the experimental unit. This study shows that refrigeration by absortion could be viable in various aplications where no electricity or mechanical energy are available.
102

Condições Operacionais para o Desenvolvimento do Mercado de Eficiência Energética no Setor Residencial: O Caso de Cochabamba, Bolívia / Operating Conditions for the Development of Market Efficiency in the Residential Sector: The Case of Cochabamba, Bolivia

Jorge Marcial Choque Ajhuacho 09 December 1998 (has links)
A próxima década oferece ao mundo um verdadeiro desafio em relação à conservação de várias formas de energia. Para isso, torna-se necessário a cooperação de vários agentes envolvidos no desenvolvimento de um mercado de eficiência energética, tais como, o governo, a agência reguladora, as empresas geradoras de eletricidade, os vendedores de equipamentos, as empresas distribuidoras de eletricidade e os consumidores. O setor residencial da cidade de Cochabamba é responsável por 44% do consumo de energia elétrica, abrange 86.88% dos consumidores do sistema elétrico de Cochabamba e tem uma taxa média de crescimento da demanda de energia elétrica de 8.S% ao ano. Este setor é muito importante e apresenta um grande potencial de conservação de energia elétrica nos três usos finais que apresentam o maior consumo (79%) em Cochabamba: refrigeração, iluminação e aquecimento da água. No presente trabalho, realiza-se a caracterização da demanda de eletricidade por usos finais em um estudo-piloto, com uma metodologia desenvolvida a partir da realização de uma pesquisa de hábitos de consumo e posse de eletrodomésticos. São analisadas as oportunidades que apresentam-se atualmente na Bolívia para viabilizar o desenvolvimento do mercado de tecnologia ecientes em razão da recente restruturação do setor elétrico boliviano que oferece sinais econômicos de mercado para atingir a eficiência econômica no fornecimento elétrico a custo mínimo. Também são analisadas as barreiras que existem na Bolívia para a introdução de tecnologias eficientes no mercado e propõem-se diversas condições que devem estabelecer-se para desenvolver um mercado de eciência energética. Analisam-se as condições operacionais associando ações do agente regulador, dos vendedores de equipamentos das empresas de energia elétrica e dos consumidores para a aceleração da penetração de tecnologias eficientes de uso final disponíveis em outros mercados. / The next decade introduces a real challenge for energy conservation. This will require the cooperation of many actors involved in an energy efficiency market as the government, the regulatory body, the electric power generating companies, the equipment vendors, the electricity distribution companies and the consumers. In the city of Cochabamba, the residential sector uses 44 percent of the total electrical energy consumption and corresponds to 86,88 percent of the electricity users. As the average demand growth rate is 8.5 percent per year, the residential sector has a large potential for electricity conservation because the three most important end-uses (lighting, refrigeration and water heating) consume 79 percent of total electricity in Cochabamba. The present work assesses the electricity end-uses through a pilot study, applying a methodology using a survey on electrical appliances and consumption. The opportunities for development of an energy efficient tecnologies market in Bolivia are also analized as the recent electricy reform is providing economic signals to achieve economic efficiency at the least-cost electricity supply. The barriers to the introduction of energy efficient tecnologies in Bolivia are also considered with the required conditions for development of a market for energy efficiency. For that purpose, the operational conditions includes the role of the regulatory agency, the equipment vendors, the electricity companies and the consumers in order to accelerate the introduction of efficient tecnologies for end uses available in other markets.
103

Implementing lean manufacturing to improve production efficiency in the manufacturing operations at the Aspen General facility

Jozaffe, Lyndon Brian January 2006 (has links)
South African producers are constantly facing competition from foreign organisations in their domestic markets. The adverse effects of this competition stem, in part, from the low levels of productivity which characterise South African industry and which is well documented by the National Productivity Institute of South Africa. The concept of continuous improvement offers a proven methodology for increasing the effectiveness and efficiency of production processes. Given the situation that faces South African producers, it would seem appropriate to investigate how the concept of continuous improvement can be applied to a specific South African manufacturing organisation, like the Aspen Pharmacare General Facility, in order to improve its effectiveness and efficiency.
104

Explaining Inefficiency in an Ontario Bail Court: Perspectives of Criminal Defence Lawyers

Grech, Diana C. January 2011 (has links)
Some academics and government officials have implicated defence counsel as the primary ‘villains’ in lengthy case processing times in Ontario bail courts. It has been suggested that defence counsel contribute to increasing case processing time through their use of ‘unproductive’ adjournments. This study examines this allegation through semi-structured interviews with defence counsel who practise in one Eastern Ontario bail court. The findings put the evidence that blames defence counsel into context and show that the explanations for their conduct are more complex than they may initially appear. They also reveal several explanations for bail inefficiency which are unrelated to the role of defence counsel but correspond grosso modo to the traditional factors associated with lengthy case processing time in the broader court process. The study concludes that although defence counsel are partly responsible for lengthy case processing times in bail court, they are only one contributor among many others.
105

Založení a provozování firmy zaměřené na outdoor a teambuilding / Establishment and Running of Firm focused on Outdoor and Teambuilding

Rucký, Tomáš January 2009 (has links)
Analysis of teambuilding and teambuilding activities paintball. Teambuilding functioning in practice, the operation of the company focused on teambuilding. Improve the efficiency of current teambuilding activities and the transition to a different organizational structure. Examples teambuilding.
106

Efficiency comparison of online and offline markets: evidence from the two largest U.S. retailers

Paskert, Niklas January 2020 (has links)
The online market has developed into an equally strong competitor to the offline market. This study examines the market efficiency of the U.S. online and offline market based on the price level, price dispersion, price elasticity and menu cost. A direct comparison of all four market efficiency criteria based on empirical results is not discussed in the literature. Here, the empirical study analyzes and compares the online and offline prices of electronic products between the two largest retailers, Amazon and Walmart. The results clearly indicate that the online market is more efficient than the offline market. Comparing the online prices between the multichannel retailer Walmart and the pure online retailer Amazon we find that for 64.5% of the electronic products, Amazon has the better offer. While 26% of the prices are identical and only 9.5% of the overall prices offered by Walmart are lower. The price advantage of Amazon is explained by the strong price linkage between the online shop and the less efficient offline shop within the retailer Walmart. In 73% of the examined prices, the online and offline prices at Walmart are identical. Furthermore, this price linkage causes a high price dispersion of 14.7% between the online shops of the two retailers. As soon as Walmart breaks the price linkage through sales offers in their online shop, the price dispersion between the two retailers drops to 10.2%.
107

Racionalizační projekt pracoviště svařování ohřívačů / Rationalization project of workplace for Hot-water Heater welding

Varjan, Matúš January 2010 (has links)
The aim of the thesis is to rationalize the water heaters welding area in Tatramat company - ohrievače s.r.o. The rationalization consists of three parts. The first part deals with the arrangement of the workplaces, the second part re-evaluates the monthly production planning. The third part describes in detail the production of one type, which based on simulations created in the simulation software Witness, compares the recorded time in company informartion system Orfert to the real production time in the operation. Each individual part offers optimization proposals and merging them into one unit, will create an efficient, transparent and economically value adding rationalization of the water heaters welding area.
108

Risk Management And Market Efficiency On The Midwest Independent System Operator Electricity Exchange.

Jones, Kevin 12 1900 (has links)
Midwest Independent Transmission System Operator, Inc. (MISO) is a non-profit regional transmission organization (RTO) that oversees electricity production and transmission across thirteen states and one Canadian province. MISO also operates an electronic exchange for buying and selling electricity for each of its five regional hubs. MISO oversees two types of markets. The forward market, which is referred to as the day-ahead (DA) market, allows market participants to place demand bids and supply offers on electricity to be delivered at a specified hour the following day. The equilibrium price, known as the locational marginal price (LMP), is determined by MISO after receiving sale offers and purchase bids from market participants. MISO also coordinates a spot market, which is known as the real-time (RT) market. Traders in the real-time market must submit bids and offers by thirty minutes prior to the hour for which the trade will be executed. After receiving purchase and sale offers for a given hour in the real time market, MISO then determines the LMP for that particular hour. The existence of the DA and RT markets allows producers and retailers to hedge against the large fluctuations that are common in electricity prices. Hedge ratios on the MISO exchange are estimated using various techniques. No hedge ratio technique examined consistently outperforms the unhedged portfolio in terms of variance reduction. Consequently, none of the hedge ratio methods in this study meet the general interpretation of FASB guidelines for a highly effective hedge. One of the major goals of deregulation is to bring about competition and increased efficiency in electricity markets. Previous research suggests that electricity exchanges may not be weak-form market efficient. A simple moving average trading rule is found to produce statistically and economically significant profits on the MISO exchange. This could call the long-term survivability of the MISO exchange into question.
109

Measurement of Power Losses of Rolling Element Bearings under Tightly ControlledTemperature and Loading Conditions

Garg, Ayush January 2020 (has links)
No description available.
110

Stiffness Factors in Material Efficiency for Automotive Application

Ng, Wei Loong 04 August 2001 (has links)
The automotive industry is moving towards a new generation of lightweight vehicles for improved fuel economy and reduced pollution. However, the industry wants to keep the vehicle size without sacrificing performance, affordability, and safety. Hence, every component which makes up an automobile, from body structure to engine and interior, are scrutinized in pursue of weight savings. Efficient geometrical design and careful material utilization are ways to bring about a significant weight reduction in the auto body. This research will show techniques to predict areas in auto body that potentially have weight savings possibility. A formula is developed to determine the relevancy of substituting steel, the material used primarily in auto body, with aluminum for the equivalent structural stiffness from weight savings standpoint. Also, the same formula can provide geometrical guideline for an efficient body structure. Finite Element Modeling software ALGOR is employed in this research to determine the maximum deflection of an auto floor pan, before and after geometrical and material alteration.

Page generated in 0.0569 seconds