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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.
1

Investigation of Optimum Operating Conditions for Recirculating Sand Filters

Weng, Yonghui 01 1900 (has links)
<p> Recirculating Sand Filters (RSFs) provide a compact method of secondary treatment to septic systems and lagoons, are relatively easy to operate and require little maintenance. Together, these characteristics render RSFs particularly appropriate for small communities and municipalities, as they offer a number of economic and operational advantages over conventional technologies. A preliminary study investigating RSF effluent quality, conducted jointly by McMaster University, the Great Lakes Sustainability Fund (GLSF) and the Ontario Ministry of the Environment (MOE) in 1999-2001, conducted pilot-scale experiments and demonstrated that municipal sewage can be successfully treated year-round by RSFs. The results of the preliminary study recommended that further work be conducted to investigate the selection of media size, dosing frequency, recycle ratio, and hydraulic loading rate. </p> <p> The primary objective of this study was to develop design and operating conditions under Ontario climatic conditions with respect to media size, dosing frequency, recycle ratio and hydraulic loading rate by conducting further pilot-scale studies. Three pilot-scale RSFs, operating in parallel, were loaded intermittently with septic tank effluent to evaluate the above mentioned operating parameters on the removal of total suspended solids (TSS), 5-day carbonaceous biochemical oxygen demand (cBOD5), total ammonia-nitrogen (TAN) and total nitrogen (TN). The addition of alum was also implemented to evaluate the removal of total phosphorus (TP). The effluent objectives for this study were based on the MOE general secondary treatment level requirements of monthly averages based on a minimum of four weekly samples. The four-phase experimental program began in April, 2004 and ended in June, 2005. Three media sizes were investigated, with d10 of 2.6, 5 and 7.7 ·mm. The applied hydraulic loading rates were 0.2 and 0.4 rnlday. Dosing frequencies of 24 and 48 times/day were observed. Recycle ratios of 300% and 500% were also evaluated. </p> <p> It was found that the RSF operating with 2.6 mm media, 500% recycle ratio and 24 times/day dosing frequency under a hydraulic loading rate of 0.2 rnlday produced the best quality effluent, and achieved the effluent objectives required by the MOE. These operating criteria, however, must still be investigated under cold weather conditions to ensure acceptable year-round performance in Ontario. With proper addition of alum, the TP effluent objective was achieved under the optimum operating conditions. </p> / Thesis / Master of Applied Science (MASc)
2

The study of treatment of oil/water emulsions using salt-assisted microwave irradiation

Kuo, Chin-Hsing 03 August 2010 (has links)
Waste oil emulsions are generated in several manufacturing processes. Such emulsions not only affect the efficacy of wastewater treatment but also influence the water quality of the effluent. Therefore, these waste oil emulsions that have to be treated before being released into the environment. Many processes have been developed for demulsifying such materials and microwave irradiation has been shown to be most effective in this respect. It does not require the addition of chemicals and the oil recovered from the emulsion can be reused. With microwave irradiation, there are two main mechanisms occurring simultaneously. One is the rapid increase of temperature which reduces the viscosity of the emulsion. The other is molecular rotation, which neutralizes the Zeta potential because of the rearrangement of electrical charges surrounding the water droplets. Hence, water droplets coalesce and result in the separation of the emulsion. Addition of inorganic salts has also been shown to improve the efficiency of microwave irradiation in demulsification owing to an increase in solvent conductivity, which accelerates the heating rate. This process is termed salt-assisted microwave irradiation. In the present study, we propose that NaCl and artificial seawater can be an economical source of cations required in salt-assisted microwave demulsification. Our experiments included batch tests of emulsion characteristics and the effects of microwave operating conditions on demulsification rate and separation efficiency of three oil-in-water (O/W) emulsions (mineral oil, vegetable oil, and mineral-oil/vegetable-oil mix). First study was aimed to examine the demulsification of an O/W cutting oil emulsion with the addition of NaCl under microwave irradiation. This work investigates the effect of a set of operating variables, including irradiation time, irradiation power, dosage of NaCl, settling time, pH and the initial oil concentration, on the separation efficiency in the treatment of an oil in water (O/W) type cutting oil emulsion by microwave assisted demulsification. As a result of a series of batch demulsification tests a set of optimum operating conditions was found, consisting of 2 min of microwave irradiation at 280 W, the addition of 14 g/L of NaCl, 60 min settling time, and at a pH of 9.5. A separation efficiency of 93.8% was obtained with these conditions for 50 mL of cutting oil emulsion with an initial oil content of 10 g/L. The objective of the second study was to examine the demulsification of an O/W cutting oil emulsion, an olive oil emulsion, and a 1:1 cutting-oil/olive-oil emulsion mix, using a proposed process termed as seawater-assisted microwave irradiation demulsification. We conducted batch demulsification tests on 50-mL aliquots with an initial oil content of 10 g/L, and found that the separation efficiencies of a cutting oil emulsion, an olive oil emulsion, and a cutting-oil/olive-oil mix reached 93.1%, 92.6%, and 93.2%, respectively, using our optimum operating conditions, which were 40 sec of microwave irradiation at 700 W, a 60 min settling time, and addition of 12%, 32%, and 20% (all v/v) of artificial seawater, respectively. Using this set of operating conditions, a decrease in solution pH was found to significantly increase the demulsification efficiency after addition of inorganic acid, whereas an increase in the concentration of surfactant, sodium dodecyl sulfate (SDS), resulted in a decrease in efficiency. In addition, our test data were explored using a stepwise regression method, yielding a multi-variable equation. This empirical equation was able to describe separation efficiency rather well, after exclusion of tests showing separation efficiency below 40% and temperature higher than the boiling point. This study could provide essential information related to O/W emulsions using salt-assisted microwave demulsification.
3

Sorption-Based Thermal Energy Storage: Material Development and Effects of Operating Conditions

Strong, Curtis 30 April 2021 (has links)
The adverse effects of climate change, the steady depletion of fossil fuels, and the industrialization of developing countries have resulted in an increased supply and demand of renewable thermal energy. Renewable thermal energy sources like solar thermal energy produce fewer local emissions but have a temporally inconsistent power output. The consumer space heating and domestic hot water demands also vary as a function of time. This creates a mismatch between thermal energy supply and demand. Energy storage is one method of solving this problem. However, conventional methods, like hot water storage, are voluminous and can only store heat for short periods of time. Therefore, compact long-term energy storage technologies, like sorption-based energy storage systems, require research and development. The current work aims to identify and develop suitable materials for sorption-based energy storage systems and to determine the effects of operating conditions on the performance of thermal energy storage systems. A material screening study was performed, which identified MCM-41, SAPO-34, and silica gel, which are all silica-based materials, as suitable materials for sorption-based energy storage. The effects of key operating variables for a silica gel/water-vapour adsorption-based energy storage system were quantified and optimized. The optimized system energy storage density value was nearly double that of unoptimized systems. The effects of salt impregnation were investigated by impregnating different hosts with MgSO4 salt and varying the concentration of the salt in the host material. All composites were stable after three hydration/dehydration cycle. A silica gel/MgSO4 hybrid containing 33 wt% MgSO4 was found to have the highest energy storage density of all of the MgSO4-based composites. Finally, CaCl2, a promising hygroscopic for thermal energy storage was stabilized via impregnation into silica gel and encapsulation in methylcellulose. A novel synthesis technique involving the simultaneous impregnation of silica gel with CaCl2 and encapsulation in methylcellulose produced a stable encapsulated salt-in matrix composite with a high energy storage performance.
4

Supporting complete vehicle reliability forecasts

Lindén, Julia January 2017 (has links)
Reliability is one of the properties that customers of heavy trucks value highest.Dependent on all parts and functions of the vehicle, reliability is a complexproperty, which can normally be measured only towards the end of a developmentproject. At earlier development stages, forecasts can give valuable decision supportfor project planning.The main function of a heavy truck is to transport goods, but the truck also hasinteractive functions as the working environment of the driver. Interactivefunctions are functions experienced by the driver. They are subjective, in the senseof being person dependent, so that a system can be experienced as inadequate byone user but satisfactory by another. Examples of interactive functions of heavytrucks are climate comfort and ergonomics, which are experienced differently bydifferent drivers. Failures of these functions lead to costs and limited availabilityfor the customer. Therefore it is important to include them in reliability forecasts.The work described in this thesis concerns some elements of the system reliabilityforecast. Two studies are presented, one proposing a qualitative systemarchitecture model and the other reviewing and testing methods for evaluating theimpact of varying operating conditions. Two case studies of a truck cab in a systemreliability test were made. The first case study shows that the system architecturemodel supports reliability forecasts by including interactive functions as well asexternal factors, human and environmental, which affect function performance.The second case study shows that modelling uncertainty is crucial for interactivefunctions and recommends a method to forecast function performance while takingvarying operating conditions into account. / <p>QC 20170602</p>
5

Otimização de condições operacionais de processo visando a minimização da emissão de material particulado na incineração industrial de resíduos perigosos / Otimization of operating conditions of process to minimize emission of particulate material in industrial hazardous waste incineration

Dip, Tatiana Maciulis 06 October 2004 (has links)
Busca-se a minimização da emissão de material particulado em incinerador industrial de resíduos perigosos através do controle operacional de algumas variáveis de processo. Essas variáveis, que afetam diretamente a qualidade da queima, são: intervalo de tempo de alimentação, modo de introdução de pequena quantidade de resíduo líquido no forno rotativo e excesso de oxigênio na saída dos gases de combustão. Todos os testes têm a mesma taxa de resíduos incinerados (kg/h). Na faixa estudada, o controle operacional mostrou resultados expressivos: em todos os casos, para cada variável estudada, a emissão de material particulado na melhor condição foi aproximadamente 2,5 vezes menor o valor da emissão de material particulado, se comparado com a pior condição de operação. / The minimization of particulate matter emissions in hazardous industrial waste incinerator was sought through operational control of some specific variables of the process. These variables, which have direct interference in the combustion quality, are: mean time between semi-batch feedings, mode of fedding of small amounts of liquid waste, and oxygen excess in the off-gas. All tests have been performed with the same feeding rate (kg/h). In the range studied, operational control showed expressive results: for each variable tested, the particulate matter emission in the worst operational point was around 2,5 times that obtained within the best condition.
6

Desenvolvimento de um modelo de dimensionamento de equipamento de escavacao e de transporte em mineração

Racia, Ismael Momade January 2016 (has links)
O motivo da dissertação “Desenvolvimento de um Modelo de Dimensionamento de Equipamentos de Escavação e de Transporte” surgiu da necessidade de apoiar no processo de decisão de dimensionamento dos principais equipamentos de mineração. Este trabalho apresenta um modelo simples e direto para dimensionar os equipamentos principais de mineração (escavadeiras e caminhões) através de uma rotina criada denominada EXCEsimulator, concebido para o cálculo da capacidade das caçambas das escavadeiras, do número dos equipamentos de escavação e de transporte, bem como os tempos de espera das unidades de transporte em carregar. Para tal, definem-se os parâmetros de produtividade e caraterísticas dos equipamentos; calcula-se aplicando um modelo determinístico de produção; e faz-se o levantamento de equipamentos existentes no mercado, reunindo as suas características e serviços prestados pelos representantes ou fabricantes das marcas. Para demostrar a funcionalidade do modelo desenvolvido, o presente trabalho demonstrou, através de um estudo de caso, o dimensionamento de uma frota de carregamento e transporte para uma mineração a céu aberto utilizando indicadores de produção, e uma comparação entre o uso de equipamentos de pequeno e grande porte no aspeto da demanda de equipamento. O estudo foi desenvolvido a partir de uma empresa de mineração hipotética baseada em dados realista. O modelo desenvolvido é aplicável a qualquer tipo de equipamento de escavação e de transporte, independente do seu porte e capacidade de produção. Como conclusão, pretende-se com esta dissertação fornecer uma ferramenta útil para o apoio à decisão de dimensionamento de equipamentos e frotas de escavação e de transporte capaz de suprir a necessidade de uma consulta de mercado. / The reason for the dissertation "Development of an Estimating Model for Excavation and Transport Equipment" arose from the need to support the decision-making process for the size of the main mining equipment. This work presents a simple and direct model for sizing the main mining equipment (excavators and trucks) through a routine created called EXCEsimulator, designed to calculate the capacity of excavator buckets, number of excavation and transport equipment, and As the waiting times of the transport units on loading. For this, the parameters of productivity and characteristics of the equipment are defined; Is calculated by applying a deterministic model of production; And it is made the survey of existing equipment in the market, gathering its characteristics and services provided by the representatives or manufacturers of the brands. To demonstrate the functionality of the developed model, the present study demonstrated, through a case study, the design of a loading and transport fleet for open pit mining using production indicators, and a comparison between the use of small equipment And large in the aspect of equipment demand. The study was developed from a hypothetical mining company based on realistic data. The developed model is applicable to any type of excavation and transportation equipment, regardless of its size and production capacity. In conclusion, it is intended with this dissertation to provide a useful tool to support the decision on sizing equipment and excavation and transport fleets capable of supplying the need for a market consultation.
7

Conceptual Internal Design And Computational Fluid Dynamics Analysis Of A Supersonic Inlet

Alemdaroglu, Mine 01 May 2005 (has links) (PDF)
ABSTRACT CONCEPTUAL INTERNAL DESIGN AND COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF A SUPERSONIC INLET ALEMDAROgLU, Mine M. S., Department of Aerospace Engineering Supervisor: Prof. Dr. Yusuf &Ouml / ZY&Ouml / R&Uuml / K May 2005, 144 pages In this thesis, the conceptual internal design of the air inlet of a supersonic, high altitude, solid propellant ramjet cruise missile is performed. Inviscid, compressible CFD analysis of the designed inlet is made in order to obtain qualitative and quantitative performance characteristics of the inlet at different operating conditions. The conceptual design of the inlet is realized by using analytical relations and equations, correlations derived from numerous available past experimental data and state-of-the-art design examples. The performance estimation of the designed inlet at different operating conditions is done by using one and two dimensional gas dynamics equations. The results of the performance estimation study are compared with the results of the CFD analysis and these results are discussed in detail. A commercial tool, CFD-FASTRAN&Ograve / , is used for the CFD analysis. Inlet flow phenomena such as, different shock patterns and shock positions, performance degradation at off-design operating conditions and inlet unstart are observed. Keywords: Supersonic Inlet, Ramjet, CFD, Inlet Performance Characteristics, Operating Conditions, Unstart
8

Desenvolvimento de um modelo de dimensionamento de equipamento de escavacao e de transporte em mineração

Racia, Ismael Momade January 2016 (has links)
O motivo da dissertação “Desenvolvimento de um Modelo de Dimensionamento de Equipamentos de Escavação e de Transporte” surgiu da necessidade de apoiar no processo de decisão de dimensionamento dos principais equipamentos de mineração. Este trabalho apresenta um modelo simples e direto para dimensionar os equipamentos principais de mineração (escavadeiras e caminhões) através de uma rotina criada denominada EXCEsimulator, concebido para o cálculo da capacidade das caçambas das escavadeiras, do número dos equipamentos de escavação e de transporte, bem como os tempos de espera das unidades de transporte em carregar. Para tal, definem-se os parâmetros de produtividade e caraterísticas dos equipamentos; calcula-se aplicando um modelo determinístico de produção; e faz-se o levantamento de equipamentos existentes no mercado, reunindo as suas características e serviços prestados pelos representantes ou fabricantes das marcas. Para demostrar a funcionalidade do modelo desenvolvido, o presente trabalho demonstrou, através de um estudo de caso, o dimensionamento de uma frota de carregamento e transporte para uma mineração a céu aberto utilizando indicadores de produção, e uma comparação entre o uso de equipamentos de pequeno e grande porte no aspeto da demanda de equipamento. O estudo foi desenvolvido a partir de uma empresa de mineração hipotética baseada em dados realista. O modelo desenvolvido é aplicável a qualquer tipo de equipamento de escavação e de transporte, independente do seu porte e capacidade de produção. Como conclusão, pretende-se com esta dissertação fornecer uma ferramenta útil para o apoio à decisão de dimensionamento de equipamentos e frotas de escavação e de transporte capaz de suprir a necessidade de uma consulta de mercado. / The reason for the dissertation "Development of an Estimating Model for Excavation and Transport Equipment" arose from the need to support the decision-making process for the size of the main mining equipment. This work presents a simple and direct model for sizing the main mining equipment (excavators and trucks) through a routine created called EXCEsimulator, designed to calculate the capacity of excavator buckets, number of excavation and transport equipment, and As the waiting times of the transport units on loading. For this, the parameters of productivity and characteristics of the equipment are defined; Is calculated by applying a deterministic model of production; And it is made the survey of existing equipment in the market, gathering its characteristics and services provided by the representatives or manufacturers of the brands. To demonstrate the functionality of the developed model, the present study demonstrated, through a case study, the design of a loading and transport fleet for open pit mining using production indicators, and a comparison between the use of small equipment And large in the aspect of equipment demand. The study was developed from a hypothetical mining company based on realistic data. The developed model is applicable to any type of excavation and transportation equipment, regardless of its size and production capacity. In conclusion, it is intended with this dissertation to provide a useful tool to support the decision on sizing equipment and excavation and transport fleets capable of supplying the need for a market consultation.
9

Desenvolvimento de um modelo de dimensionamento de equipamento de escavacao e de transporte em mineração

Racia, Ismael Momade January 2016 (has links)
O motivo da dissertação “Desenvolvimento de um Modelo de Dimensionamento de Equipamentos de Escavação e de Transporte” surgiu da necessidade de apoiar no processo de decisão de dimensionamento dos principais equipamentos de mineração. Este trabalho apresenta um modelo simples e direto para dimensionar os equipamentos principais de mineração (escavadeiras e caminhões) através de uma rotina criada denominada EXCEsimulator, concebido para o cálculo da capacidade das caçambas das escavadeiras, do número dos equipamentos de escavação e de transporte, bem como os tempos de espera das unidades de transporte em carregar. Para tal, definem-se os parâmetros de produtividade e caraterísticas dos equipamentos; calcula-se aplicando um modelo determinístico de produção; e faz-se o levantamento de equipamentos existentes no mercado, reunindo as suas características e serviços prestados pelos representantes ou fabricantes das marcas. Para demostrar a funcionalidade do modelo desenvolvido, o presente trabalho demonstrou, através de um estudo de caso, o dimensionamento de uma frota de carregamento e transporte para uma mineração a céu aberto utilizando indicadores de produção, e uma comparação entre o uso de equipamentos de pequeno e grande porte no aspeto da demanda de equipamento. O estudo foi desenvolvido a partir de uma empresa de mineração hipotética baseada em dados realista. O modelo desenvolvido é aplicável a qualquer tipo de equipamento de escavação e de transporte, independente do seu porte e capacidade de produção. Como conclusão, pretende-se com esta dissertação fornecer uma ferramenta útil para o apoio à decisão de dimensionamento de equipamentos e frotas de escavação e de transporte capaz de suprir a necessidade de uma consulta de mercado. / The reason for the dissertation "Development of an Estimating Model for Excavation and Transport Equipment" arose from the need to support the decision-making process for the size of the main mining equipment. This work presents a simple and direct model for sizing the main mining equipment (excavators and trucks) through a routine created called EXCEsimulator, designed to calculate the capacity of excavator buckets, number of excavation and transport equipment, and As the waiting times of the transport units on loading. For this, the parameters of productivity and characteristics of the equipment are defined; Is calculated by applying a deterministic model of production; And it is made the survey of existing equipment in the market, gathering its characteristics and services provided by the representatives or manufacturers of the brands. To demonstrate the functionality of the developed model, the present study demonstrated, through a case study, the design of a loading and transport fleet for open pit mining using production indicators, and a comparison between the use of small equipment And large in the aspect of equipment demand. The study was developed from a hypothetical mining company based on realistic data. The developed model is applicable to any type of excavation and transportation equipment, regardless of its size and production capacity. In conclusion, it is intended with this dissertation to provide a useful tool to support the decision on sizing equipment and excavation and transport fleets capable of supplying the need for a market consultation.
10

Otimização de condições operacionais de processo visando a minimização da emissão de material particulado na incineração industrial de resíduos perigosos / Otimization of operating conditions of process to minimize emission of particulate material in industrial hazardous waste incineration

Tatiana Maciulis Dip 06 October 2004 (has links)
Busca-se a minimização da emissão de material particulado em incinerador industrial de resíduos perigosos através do controle operacional de algumas variáveis de processo. Essas variáveis, que afetam diretamente a qualidade da queima, são: intervalo de tempo de alimentação, modo de introdução de pequena quantidade de resíduo líquido no forno rotativo e excesso de oxigênio na saída dos gases de combustão. Todos os testes têm a mesma taxa de resíduos incinerados (kg/h). Na faixa estudada, o controle operacional mostrou resultados expressivos: em todos os casos, para cada variável estudada, a emissão de material particulado na melhor condição foi aproximadamente 2,5 vezes menor o valor da emissão de material particulado, se comparado com a pior condição de operação. / The minimization of particulate matter emissions in hazardous industrial waste incinerator was sought through operational control of some specific variables of the process. These variables, which have direct interference in the combustion quality, are: mean time between semi-batch feedings, mode of fedding of small amounts of liquid waste, and oxygen excess in the off-gas. All tests have been performed with the same feeding rate (kg/h). In the range studied, operational control showed expressive results: for each variable tested, the particulate matter emission in the worst operational point was around 2,5 times that obtained within the best condition.

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