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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

A NUMERICAL EVALUATION OF THE DESIGN OF AN AUTOTHERMAL REFORMER FOR THE ONBOARD PRODUCTION OF HYDROGEN FROM ISO-OCTANE

HUSSAIN, SHAFQAT 09 March 2009 (has links)
A numerical study was carried out to improve the design of an autothermal reformer for the onboard production of hydrogen to be used in fuel-cell- powered auxiliary power units (APU) to provide heating and electricity in long haul trucks when they are at rest. The development of these auxiliary power units is based upon the use of power generated by solid oxide fuel cell (SOFC) system, instead of from a conventional gasoline engine. The present work was undertaken to improve the design of a prototype autothermal fuel reformer that had been developed by the Fuel Cell Research Centre (FCRC) at Queen’s University to convert liquid hydrocarbon truck fuel to a hydrogen rich product gas. In this development work and in the previous work iso-octane (C8H18) has been used as a surrogate fuel. Using this surrogate of gasoline, the reformer was simulated using various inlet steam/carbon (H2O/C), oxygen/carbon (O/C) molar ratios and gas-hourly-space-velocity (GHSV). In the reformer considered the reforming process is carried out in a compact tubular reactor with a centerline thermocouple tube using a 2% Pt-ZrCe based catalyst with a local porosity of 0.6. During the initial simulations, it was observed that near the start of the catalyst region there were large temperature gradients due to an exothermic partial oxidation reaction. In order to reduce the temperature gradients and facilitate heat transfer by conduction along the reformer, the central thermocouple tube was replaced with a central solid rod. The effects of variations in the thermal conductivity of central solid rod, of the reactor wall, of the catalyst bed, of the inert porous material near the inlet and the outlet of the catalyst bed, of the gas hourly space velocity, of the effectiveness factor of the chemical reaction mechanism on the performance of the reactor were studied. The results so obtained were analyzed to determine potential design improvements that would increase the hydrogen output. The results were compared with the previous numerical and experimental results obtained in the previous studies of the reformer and found to be in good agreement with the general trends of the temperature profiles as well as the outlet molar concentrations of product species. After the analysis and evaluation of all the results, it was found that by replacement of central thermocouple tube with central solid rod made of high conductivity material and by using material for inert porous region at the outlet that had a thermal conductivity equal to that of the catalyst bed led to more even temperature profiles within the catalyst region. It was also found that the hydrogen molar percentage output could be increased by approximately more than 25% and that the length of the reactor could be reduced by 20mm by incorporating these changes in the reformer design. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2009-03-09 12:14:27.627
2

Development of an Ab/Adduction Power Unit for a Lower Extremity Exoskeleton

Jelley, Samuel Flaherty 23 May 2022 (has links)
No description available.
3

DEVELOPMENT OF A PLANETARY STYLE POWER UNIT FOR A LOWER EXTREMITY EXOSKELETON

Connerton, Michael J. 26 August 2019 (has links)
No description available.
4

Análise econômica financeira comparativa da autoprodução direta ou conectada no SIN - um estudo de caso. / The comparative economic financial analysis of the direct self production or connected to SIN (National Interconnected System) case analysis.

Midea, Leonardo Granada 26 May 2009 (has links)
Este trabalho tem como objetivo principal verificar a viabilidade econômica financeira da autoprodução direta e interligada, isto é, elaborar uma comparação entre uma usina hidrelétrica ligada diretamente à unidade de consumo, e uma usina ligada ao Sistema Interligado Nacional, com potência e energia asseguradas. Para isso, foram utilizados, como premissas, uma indústria de alumínio que, como parte integrante dos grandes consumidores de energia brasileira, é um tipo de indústria eletro-intensiva, e emprega milhares de pessoas direta e indiretamente; também uma usina hidrelétrica, que neste trabalho foi a UHE Piraju, usina de concessão da CIA BRASILEIRA DE ALUMÍNIO, que gentilmente cedeu os dados de geração física real. Foram adotadas as seguintes metodologias para comparação da viabilidade, utilizando um cenário de geração e preços SPOT dos anos de 2006 e 2007: (i) Autoprodução Direta: Geração física real, comercializando excedentes e comprando energia do mercado ao preço SPOT quando necessário, e considerando todos os encargos e benefícios deste tipo de ligação; (ii) Autoprodução Conectada no SIN: Energia Assegurada Sazonalizada em 3 cenários distintos, Flat, com sazonalização moderada e sazonalização otimizada, considerando também os custos de conexão e encargos pertinentes para cada cenário. Os resultados apresentados mostram que, por pouca margem de diferença, foi mais vantajoso o cenário com a energia assegurada otimizada, porém, é possível verificar que, ponderando os resultados apresentados nos diversos cenários, verificamos que é mais viável a usina ligada diretamente à carga, pois a previsibilidade do mercado de preços de curto prazo é pequena, e dificilmente se acertaria com precisão os PLD´s registrados no ano seguinte ao da sazonalização. Contudo, o Decreto no 5.163, de 30 de Julho de 2004, através do Artigo 71, somente permite que usinas sejam ligadas diretamente à carga se estiverem dentro do mesmo sítio. O proposto é a inclusão de um novo parágrafo no Artigo 71 com condições de economicidade para a permissão da ligação da usina diretamente ao consumo. / The main goal of this study is to verify the economic financial feasibility of the direct self production, it means, of a hydropower unit directly connected to a consumption unit and to a hydropower unit connected to the SIN, with guaranteed power and energy. For this purpose, the study used as pattern an aluminum industry, which, as part of the Brazilian hall of the major energy users, a type of electric-intensive industry, and that involves thousands of employees directly and indirectly, as well as an hydroelectric power unit, which in this study was the UHE Piraju, the energy authorized supplier unit of the CIA BRASILEIRA DE ALUMÍNIO, who gently provided the real generation data. The following methodology were adopted to compare the feasibility, using a generation scenario and SPOT values of 2006 and 2007: (i) Direct Self Production: Real generation, trading leftovers and acquiring market energy at SPOT values, when required, and considering all costs and benefits of this type of connection; (ii) SIN Connected Self production: guaranteed seasoned energy in different scenarios, Flat, with seasonalization moderated and seasonalization optimized, also considering the connection and applicable costs for each scenario. The presented results indicated that, for a small difference, the most advantageous scenario was the one with optimized guaranteed energy, however, it is possible to verify that evaluating the presented results in the different cases, it was verified that is more feasible the unit directed connected to a demand, since the forecast of short term values market is small, and it would hardly precise ascertain with the registered PLD (Settlement Price for the Differences) in the following year of the seasonalization. However, the Act n. 5.163, July 30, 2004, through the Article 71 only allows power units to be connected to the demand if they are in the same site. The proposal is the inclusion of a new paragraph in the Article 71 with economic conditions in order to allow the connection between the power unit to the consumption.
5

Análise econômica financeira comparativa da autoprodução direta ou conectada no SIN - um estudo de caso. / The comparative economic financial analysis of the direct self production or connected to SIN (National Interconnected System) case analysis.

Leonardo Granada Midea 26 May 2009 (has links)
Este trabalho tem como objetivo principal verificar a viabilidade econômica financeira da autoprodução direta e interligada, isto é, elaborar uma comparação entre uma usina hidrelétrica ligada diretamente à unidade de consumo, e uma usina ligada ao Sistema Interligado Nacional, com potência e energia asseguradas. Para isso, foram utilizados, como premissas, uma indústria de alumínio que, como parte integrante dos grandes consumidores de energia brasileira, é um tipo de indústria eletro-intensiva, e emprega milhares de pessoas direta e indiretamente; também uma usina hidrelétrica, que neste trabalho foi a UHE Piraju, usina de concessão da CIA BRASILEIRA DE ALUMÍNIO, que gentilmente cedeu os dados de geração física real. Foram adotadas as seguintes metodologias para comparação da viabilidade, utilizando um cenário de geração e preços SPOT dos anos de 2006 e 2007: (i) Autoprodução Direta: Geração física real, comercializando excedentes e comprando energia do mercado ao preço SPOT quando necessário, e considerando todos os encargos e benefícios deste tipo de ligação; (ii) Autoprodução Conectada no SIN: Energia Assegurada Sazonalizada em 3 cenários distintos, Flat, com sazonalização moderada e sazonalização otimizada, considerando também os custos de conexão e encargos pertinentes para cada cenário. Os resultados apresentados mostram que, por pouca margem de diferença, foi mais vantajoso o cenário com a energia assegurada otimizada, porém, é possível verificar que, ponderando os resultados apresentados nos diversos cenários, verificamos que é mais viável a usina ligada diretamente à carga, pois a previsibilidade do mercado de preços de curto prazo é pequena, e dificilmente se acertaria com precisão os PLD´s registrados no ano seguinte ao da sazonalização. Contudo, o Decreto no 5.163, de 30 de Julho de 2004, através do Artigo 71, somente permite que usinas sejam ligadas diretamente à carga se estiverem dentro do mesmo sítio. O proposto é a inclusão de um novo parágrafo no Artigo 71 com condições de economicidade para a permissão da ligação da usina diretamente ao consumo. / The main goal of this study is to verify the economic financial feasibility of the direct self production, it means, of a hydropower unit directly connected to a consumption unit and to a hydropower unit connected to the SIN, with guaranteed power and energy. For this purpose, the study used as pattern an aluminum industry, which, as part of the Brazilian hall of the major energy users, a type of electric-intensive industry, and that involves thousands of employees directly and indirectly, as well as an hydroelectric power unit, which in this study was the UHE Piraju, the energy authorized supplier unit of the CIA BRASILEIRA DE ALUMÍNIO, who gently provided the real generation data. The following methodology were adopted to compare the feasibility, using a generation scenario and SPOT values of 2006 and 2007: (i) Direct Self Production: Real generation, trading leftovers and acquiring market energy at SPOT values, when required, and considering all costs and benefits of this type of connection; (ii) SIN Connected Self production: guaranteed seasoned energy in different scenarios, Flat, with seasonalization moderated and seasonalization optimized, also considering the connection and applicable costs for each scenario. The presented results indicated that, for a small difference, the most advantageous scenario was the one with optimized guaranteed energy, however, it is possible to verify that evaluating the presented results in the different cases, it was verified that is more feasible the unit directed connected to a demand, since the forecast of short term values market is small, and it would hardly precise ascertain with the registered PLD (Settlement Price for the Differences) in the following year of the seasonalization. However, the Act n. 5.163, July 30, 2004, through the Article 71 only allows power units to be connected to the demand if they are in the same site. The proposal is the inclusion of a new paragraph in the Article 71 with economic conditions in order to allow the connection between the power unit to the consumption.
6

Condition Monitoring for hydraulic Power Units – user-oriented entry in Industry 4.0

Laube, Martin, Haack, Steffen 02 May 2016 (has links) (PDF)
One of Bosch Rexroth’s newest developments is the ABPAC power unit, which is both modular and configurable. The modular design of the ABPAC is enhanced by a selfcontained Condition Monitoring System (CMS), which can also be used to retrofit existing designs. This dissertation shows how Industry 4.0-Technology provides special advantages for the diverse user profiles. Today, Hydraulic Power Units have either scheduled intervals for preventive maintenance or are repaired in case of component failures. Preventive maintenance concepts, until now, did not fully utilize the entire life expectancy of the components, causing higher maintenance costs and prolonged downtimes. Risk of unscheduled downtime forces the customer to stock an array of spare parts leading to higher inventory costs or in the event a spare is not readily available, the customer may encounter long delivery times and extended downtime. Bearing this in mind, we’ve conceived the idea of a self-contained intelligent Condition Monitoring System including a predictive maintenance concept, which is explained in the following.
7

Řízení projektů v obchodní firmě zabývající se vývozem investičních celků / Project management in Trade Company focused on capital equipment export

Schrimpel, Michal January 2011 (has links)
The master’s thesis is focused on project management in Trade Company engaged in export of capital equipment. The Company expanded its offered product portfolio and now is focused to small cogeneration unit market. This work proposed a solution of project management in this new market area. The proposed solution is applied to a specific project of installation of small cogeneration unit.
8

Konstrukce univerzálního hydraulického agregátu / Design of universal hydraulic power unit

Holub, Vojtěch January 2015 (has links)
The first part of this masters thesis deals with research of modulat type hydraulics power units from other significant world producers. Design part of thesis contains complete design of three product ranges of hydraulics power units. It also includes simulation by FEM method. Last part descibe safety of machine and brief economic evaluation of product.
9

Condition Monitoring for hydraulic Power Units – user-oriented entry in Industry 4.0

Laube, Martin, Haack, Steffen January 2016 (has links)
One of Bosch Rexroth’s newest developments is the ABPAC power unit, which is both modular and configurable. The modular design of the ABPAC is enhanced by a selfcontained Condition Monitoring System (CMS), which can also be used to retrofit existing designs. This dissertation shows how Industry 4.0-Technology provides special advantages for the diverse user profiles. Today, Hydraulic Power Units have either scheduled intervals for preventive maintenance or are repaired in case of component failures. Preventive maintenance concepts, until now, did not fully utilize the entire life expectancy of the components, causing higher maintenance costs and prolonged downtimes. Risk of unscheduled downtime forces the customer to stock an array of spare parts leading to higher inventory costs or in the event a spare is not readily available, the customer may encounter long delivery times and extended downtime. Bearing this in mind, we’ve conceived the idea of a self-contained intelligent Condition Monitoring System including a predictive maintenance concept, which is explained in the following.
10

Geographic Information System (GIS) Simulation of Emergency Power Production from Disaster Debris in a Combined Heat and Power (CHP) System

Ryals, Christopher Shannon 30 April 2011 (has links)
The objective of this study is to determine a predicted energy capacity of disaster debris for the production of emergency power using a combined heat and power (CHP) unit. A prediction simulation using geographic information systems (GIS) will use data from past storms to calculate an estimated amount of debris along with an estimated energy potential of said debris. Rather than the expense and burden of transporting woody debris such as downed trees and wood framing materials offsite, they can be processed (sorting and chipping) to provide an onsite energy source to provide power to emergency management facilities such as shelters in schools and hospitals. A CHP unit can simultaneously produce heat, cooling effects and electrical power using various biomass sources.This study surveys the quantity and composition of debris produced for a given classification of disaster and location. A comparison of power efficiency estimates for various disasters is conducted.

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