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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.
511

Performance Modeling and Benchmark Analysis of an Advanced 4WD Series-Parallel PHEV Using Dynamic Programming

Kaban, Stefan 23 April 2015 (has links)
Advanced hybrid vehicle architectures can exploit multiple power sources and optimal control to achieve high efficiency operation. In this work, a method for generating the best-possible energy efficiency benchmark for a hybrid architecture is introduced. The benchmark program uses Dynamic Programming to analyse a reduced-fidelity MATLAB model over standard driving cycles, and bypasses vehicle controls to identify the optimal control actions and resulting fuel consumption of the Series-Parallel Multiple-Regime retrofitted PHEV of the UVic EcoCAR2 program. The simulation results indicate an optimal fuel consumption value of 4.74L/100km, in the parallel regime, compared to the stock Malibu's 8.83L/100km. The results are found to be sensitive to the allowed level of regenerative braking, with an optimal consumption value of 6.56L/100km obtained with restricted regen power limits. The parallel regime provided more efficient operation overall, especially during more aggressive driving conditions. However, the series regime provided more desirable operation during gentle driving conditions, where opportunities for regenerative braking are limited. The generated powertrain control profiles were then used to drive a higher-fidelity Simulink model. Due to the significant difference between the model structures of the MATLAB and Simulink models, comparison of results were not conclusive. A different simulation approach is required to make this proof-of-concept more useful for controls development. This research forms the foundation for further studies. / Graduate / 0540 / snkaban@gmail.com
512

Development of control strategies to optimize the fuel economy of hybrid electric vehicles

Ramaswamy, Nikhil 22 May 2014 (has links)
This thesis (1) reports a new Dynamic Programming (DP) approach, and (2) reports a Real Time Control strategy to optimize the energy management of a Hybrid Electric Vehicle(HEV). Increasing environmental concerns and rise in fuel prices in recent years has escalated interest in fuel efficient vehicles from government, consumers and car manufacturers. Due to this, Hybrid electric vehicles (HEV) have gained popularity in recent years. HEV’s have two degrees of freedom for energy flow controls, and hence the performance of a HEV is strongly dependent on the control of the power split between thermal and electrical power sources. In this thesis backward-looking and forward-looking control strategies for two HEV architectures namely series and parallel HEV are developed. The new DP approach, in which the state variable is not discretized, is first introduced and a theoretical base is established. We then prove that the proposed DP produces globally optimal solution for a class of discrete systems. Then it is applied to optimize the fuel economy of HEV's. Simulations for the parallel and series HEV are then performed for multiple drive cycles and the improved fuel economy obtained by the new DP is compared to existing DP approaches. The results are then studied in detail and further improvements are suggested. A new Real Time Control Strategy (RTCS) based on the concept of preview control for online implementation is also developed in this thesis. It is then compared to an existing Equivalent Cost Minimization Strategy (ECMS) which does not require data to be known apriori. The improved fuel economy results of the RTCS for the series and parallel HEV are obtained for standard drive cycles and compared with the ECMS results
513

Hybrid Energy System for Off – Grid Rural Electrification(Case study Kenya)

Oama, Clint Arthur January 2011 (has links)
The aim of this thesis study is to design a hybrid energy system comprised of wind turbines, diesel generators and batteries to provide electricity for an off - grid rural community in Kenya. Wind Measurements collected over six years from 12 locations in Kenya have been studied and one site selected for this project due to its wind potential, geographical location and socio-economic potential. The energy system is designed to cater for the electricity demand of 500 households, one school, one medical clinic and an irrigation system. The system will support up to 3000 people. The Hybrid Optimization Model for Electric Renewables (HOMER) is the software tool that has been used to simulate the hybrid system and analyze its results. The optimization has been carried out and presented according to cost of electricity and sensitivity graphs have been used demonstrate the optimization based on diesel price and wind turbine hub height.
514

Design, simulation, and construction of a series hybrid electric vehicle

Northcott, Daniel Ross 27 September 2007 (has links)
This thesis evaluates a series hybrid electric drivetrain design for use in parking patrol vehicles. Due to the particular attributes of this application, it is proposed that the design would improve the energy efficiency of such a vehicle. The scheme is evaluated in depth through the use of electromagnetic transient simulation tools, which are used to create a highly accurate model of the vehicle. A prototype vehicle of the same design is built, and used to verify and improve the accuracy of the simulation model. The simulation model is then used to predict the energy efficiency of the series hybrid design for parking patrol. This simulation based design strategy is proposed as a method for more rapid and cost effective design of hybrid electric vehicles.
515

Design of lightweight electric vehicles

De Fluiter, Travis. January 2008 (has links)
Thesis (M.E. Mechanical Engineering)--University of Waikato, 2008. / Title from PDF cover (viewed October 2, 2008) Includes bibliographical references (p. 131-136)
516

Simulation and optimization of a fuel cell hybrid vehicle

Brown, Darren. January 2008 (has links)
Thesis (M.S.)--University of Delaware, 2008. / Principal faculty advisors: Ajay K. Prasad and Suresh G. Advani, Dept. of Mechanical Engineering. Includes bibliographical references.
517

Propriétés optomécaniques, vibrationelles et thermiques de membranes de graphène suspendues / Optomechanical, vibrational and thermal properties of suspended graphene membranes

Schwarz, Cornelia 15 January 2016 (has links)
Le but de la Nano- Opto- Mécanique et Electronic à base de graphène est d'utiliser des membranes de graphène en suspension comme blocs de construction pour aborder le couplage entre l'optique, la mécanique et l'électronique dans ce nouveau matériau. Avec un module d'Young similaire à celui du diamant (1 TPA), le graphène est une membrane extrêmement rigide, légère et mince (epaaisseur de seulement un atome) qui peut supporter son propre poids sans effondrement ou la rupture lorsqu'il est suspendu. Ces membranes, intégrées dans des dispositifs mécaniques, peuvent être actionnés à partir de DC jusqu'à des fréquences de vibration mécaniques très élevées (GHz). En outre, le graphène est un gaz d'électrons 2D exposé pour lequel une porte électrostatique tunes considérablement la densité de porteurs de charge et ses propriétés optiques. Last but not least, il offre une architecture unique pour effectuer la fonctionnalisation physico-chimiques et obtenir des matériaux hybrides combinant les propriétés particulières des espèces chimisorbées avec ceux du graphène. / The aim of the Graphene Nano- Opto- Mechanics and Electronics is to use suspended graphene membranes as building blocks to address the coupling of optics, mechanics and electronics in this novel material. With a Young modulus similar to that of diamond (1 TPa), graphene is an extremely stiff, light and atomically thin membrane that can withstand its own weight without collapsing or breaking when suspended. Such membranes, integrated as mechanical devices, can be actuated from DC up to very high mechanical vibration frequencies (GHz). Moreover, graphene is an exposed 2D electron gas for which an electrostatic gate dramatically tunes the charge carrier density and its optical properties. Last but not least, it provides a unique architecture to perform physico-chemical functionalization and obtain hybrid materials combining the peculiar properties of adsorbed and chemisorbed species with the graphene ones.
518

An Evaluation of Chemical, Biological, and Combined Chemical-Biological Approaches for Controlling Snails in Aquaculture Ponds

Noatch, Matthew R. 01 May 2010 (has links)
Digenetic trematodes are a common pest problem in aquaculture where their unappetizing appearance often reduces the marketability of food fish. Aquatic snails are intermediate hosts in the trematode lifecycle and are commonly targeted with control measures to prevent the crop fish from becoming infected. I evaluated several chemical and biological snail control strategies as alternatives to the potentially invasive black carp. Copper sulfate, hydrated lime slurry, and several fish and decapod species were tested for effectiveness against physid (Physa spp.) and planorbid (Helisoma spp.) snails in laboratory aquaria trials. Hydrated lime demonstrated effectiveness with the least potential to be toxic to cultured fish in regional application. Hybrid sunfish (redear × green sunfish) consumed large quantities of both snails in ad libitum feedings. The most effective biological (redear × green sunfish) and chemical (hydrated lime) control methods identified in the laboratory were evaluated further in research ponds. Hydrated lime applications of 9.07 kg over 9.14 m2 were found to be effective against Helisoma spp. confined to enclosures along the pond shoreline; average survival was 2%. When stocked in aquaculture ponds, hybrid redear sunfish did not significantly influence snail capture rates; however ponds stocked with redear sunfish experienced a gradual decrease in snail populations throughout the 2008 growing season. Hydrated lime and a combination of redear sunfish and hybrid redear sunfish were evaluated separately and in tandem as a combined chemical/biological treatment in the 2009 growing season. Evaluation occurred under mock production conditions in which hybrid striped bass were raised in the research ponds to determine snail treatment effects on trematode abundance. Ponds stocked with sunfish at 494 fish/ha had snail densities significantly (P ≤ 0.05) lower than control ponds after two months. Ponds treated with hydrated lime at 31.7 kg/31.5 m of shoreline in a 1 m swath experienced 99% estimated reductions in snail densities following application, but snail populations rebounded to previous levels within two months. The mean snail density in ponds treated with both hydrated lime and sunfish was significantly lower than control one month post treatment; this mean rebounded slightly by the conclusion of the trial, but not as much as in the chemical treatment group. Hybrid striped bass examined thoroughly for trematodes revealed a positive relationship between trematode abundance in fish and increasing Helisoma densities. This relationship was most apparent when estimates of snail density from only the beginning of the trial were used. Based on these results, it appears that a nearly complete reduction of Helisoma, particularly at the time of stocking fingerlings, is necessary to avoid a high abundance of trematodes in cultured fish. To this end, an early-season application of molluscicides followed closely by stocking of predator sunfish has potential to achieve a uniformly low density of snails throughout the growing season.
519

Analýza podmínek chovu u brojlerů kuřat s přihlédnutím k mikroklimatickým podmínkám při řízeném režimu / Analysi breeding condition in broiler chickens taking into account the microclimatic condition in controlled mode.

SVOBODA, Zdeněk January 2015 (has links)
This thesis is focused on the assessment of production of broiler chickens te. hybrids ROSS and COBB 308 500, in connection with the microclimate conditions in the period from 2011 to 2014. The survey provides calculation of average lengths of broiler fattening, live weight of broiler chickens at the end of the batch, consumption of complete feed mixture for 1 kg of live weight gain, the effectiveness index of fattening, mortality to reproductive breeding age on. The juxtaposition of these zootechnical parameters will be obtained from the company Tagrea s.r.o. with operations in Čekanice near Tabor.
520

Intervenções artísticas nos espaços da ciência : elementos de aprendizagem para além do ordinário

Telles, Jardel January 2016 (has links)
Com este trabalho desejamos apresentar o campo pós-estruturalista e a visão pósmoderna de ciência não asséptica, entendendo que este posicionamento nos possibilita um olhar mais amplo para o processo de ensino e aprendizagem das cientificidades. Como localizar a ciência na rede complexa de construção do conhecimento e qual a relação e aproximação que se pode fazer destes conhecimentos com os estudos da arte? É possível olhar a ciência através dos óculos das Artes Híbridas? É possível construir o conhecimento posto curricularmente de outra maneira? É possível pensar este currículo como um campo de disputas onde os caminhos da ciência foram “purificados” em busca de uma assepsia idealizada? Destacamos os instrumentos utilizados para a composição de uma oficina híbrida que versa sobre a potência das Artes Híbridas no ensino de Química e a relevância de um professor que entende o seu papel como o de intelectual específico. Versamos ainda sobre a produção de todo material artístico utilizado (fotografia, vídeo, literatura, jornalismo, história, política, filosofia, etc.), e a importância das escolhas dos métodos, dos conteúdos, dos conceitos, das abordagens e da materialidade para este educador específico em suas práticas discursivas. Pensar, ainda, na possibilidade e potência de uma produção híbrida dos participantes da oficina, nos entendimentos de Bruno Latour. Analisar estes escritos narrativos que versem sobre a Química da guerra e suas aproximações possíveis com as artes híbridas, entendendo esta produção como monumentos construídos em um campo discursivo a partir de posições e de possibilidades para além das tradicionais, reconstruindo o nó gordio no emaranhado dos saberes. / This work intends to present the post-structuralism camp and the post-modern view of cience, taking this perspective as a broader understanding of science teaching and learning process. How to locate science in the complex web of knowledge construction and what is its relation to the sudy of Arts? Is it possible to look science through the glasses of Hybrid Arts? Is it possible to construct the school curriculum knowledge in a different way? Is it possible to see the school curriculum as a field of disputes where the paths for science are “purified” for an idealised asepsis? I highlight the used instruments for the composition of an hybrid workshop which discusses the power of Hybrid Arts in the teaching of Chemistry and the importance of a teacher that can see himself/herself as a specific intellectual. I discuss the importance of choosing specific methods, contents, concepts, approaches and materials for the specific educator durig his/her discursive practices. It is also important to think about an hybrid prodution, in Bruno Latour’s view, at the end of the workshop, by the participants. And, finally, to analyse these writings, which have journalistic features and discuss the Chemistry of war and its possible relations to Hybrid Arts. I see this productions as monuments which were built in a discursive field, from non-traditional positions and perspectives, reconstructing the Gordian knot in the knowledge interweaving.

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