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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.
31

Avaliação da utilização do dióxido de carbono proveniente da fermentação alcoólica no cultivo de Spirulina (Arthrospira) platensis: uso simultâneo de nitrato de sódio e sulfato de amônio como fontes de nitrogênio em fotobiorreator aberto / Evaluation of the use of carbon dioxide from alcoholic fermentation on Spirulina (Arthrospira) platensis cultivation: simultaneous use of sodium nitrate and ammonium sulphate as nitrogen sources in open photobioreactor

Mayla Santos Rodrigues 10 February 2012 (has links)
O principal objetivo deste trabalho foi a avaliação do potencial da utilização do dióxido de carbono proveniente da fermentação alcoólica no cultivo Spirulina (Arthrospira) platensis, visando demonstrar a possibilidade do uso de um gás efluente na produção de biomassa microbiana de alto valor comercial. Para tanto, tal cianobactéria foi cultivada em tanques abertos, em escala laboratorial, em temperatura de 30 ± 1 °C e intensidade luminosa de 156 ± 20 µmol fótons m-2 s-1. O estudo de diversas variáveis de cultivo levou à fixação das seguintes condições: concentração do inóculo de 400 ± 20 mg L-1; pH de 9,0 ± 0,3, controlado por meio da adição de dióxido de carbono proveniente de cilindros; meio de cultura Schlösser, modificado de maneira a conter 0,497 e 16,4 g L-1 de carbonato e bicarbonato de sódio, respectivamente, e apenas 5,9 mM de nitrato de sódio; adição de 7,5 mM de sulfato de amônio no decorrer de 13 dias, em quantidades diárias exponencialmente crescentes, através do processo descontínuo alimentado de cultivo. Sob tais condições foram obtidos os seguintes resultados: concentração celular máxima (Xm) de 2990 mg L-1, produtividade celular (PX) de 185 mg L-1 d-1, velocidade específica máxima de crescimento (µm) de 0,42 d-1, fator de conversão de nitrogênio em células (YX/N) de 8,85 mg mg-1, teor final de clorofila (CLf) de 4,3 mg g-1, e teores de proteínas (PTN) e lipídeos (LIP) de 35 e 21 %, respectivamente. Com a finalidade de estimular o crescimento celular de A. platensis, optou-se por aumentar o valor da intensidade luminosa de 156 para 192 ou 252 ± 20 µmol fótons m-2 s-1 no 5º, 8º ou 11º dia de cultivo. Os melhores resultados cinéticos (Xm = 3954 mg L-1, PX = 253 mg L-1 d-1) e de conteúdo da biomassa (CLf = 4,2 mg g-1, PTN = 28 %, LIP = 19 %) foram obtidos com aumento da intensidade luminosa para 192 ± 20 µmol fótons m-2 s-1 no 8º dia de cultivo. Os ensaios realizados sob tais condições otimizadas, porém com dióxido de carbono proveniente da fermentação alcoólica, levaram à obtenção dos seguintes resultados: Xm = 3298 mg L-1, PX = 206 mg L-1 d-1, CLf = 4,0 mg g-1, PTN = 28 %, LIP = 17 %. Por fim, conclui-se viável a utilização do gás carbônico resultante da fermentação alcoólica no cultivo de A. platensis. Sugere-se um estudo mais aprofundado da influência desse gás efluente industrial no metabolismo e crescimento de tal microrganismo fotossintetizante, a fim de possibilitar a obtenção de resultados de concentração e produtividade celulares tão altos quanto aqueles obtidos quando do uso de gás carbônico puro. / The main objective of this work was the evaluation of the potential of using carbon dioxide from alcoholic fermentation on Spirulina (Arthrospira) platensis cultivation, aiming to prove the feasibility of applying an effluent gas in the production of high added-value microbial biomass. In order to do so, the cyanobacterium was cultivated in laboratorial-scale open raceway tanks at temperature 30 ± 1 °C and light intensity 156 ± 20 µmol photons m-2 s-1. After the study of several cultivation variables, the following conditions were set: inoculum concentration 400 ± 20 mg L-1; pH 9,0 ± 0,3, controlled by the addition of carbon dioxide from cylinders; Schlösser medium, modified as to contain 0,497 and 16,4 g L-1 sodium carbonate and bicarbonate, respectively, and only 5,9 mM sodium nitrate; addition of 7,5 mM ammonium sulphate throughout 13 days, at exponentially increasing amounts, by the fed-batch cultivation process. Under such conditions, the following results were obtained: maximum cell concentration Xm = 2990 mg L-1, cell productivity PX = 185 mg L-1 d-1, maximum specific growth rate µm = 0,42 d-1, cell to nitrogen conversion factor YX/N = 8,85 mg mg-1, final chlorophyll content CLf = 4,3 mg g-1, and content of proteins (PTN) and lipids (LIP) of 35 and 21 %, respectively. Objectiving further optimized A. platensis growth, it was chosen to increase the light intensity from 156 to 192 or 252 ± 20 µmol photons m-2 s-1 on the 5th, 8th or 11th day of cultivation. The best results in terms of growth (Xm = 3954 mg L-1, PX = 253 mg L-1 d-1) and biomass content (CLf = 4,2 mg g-1, PTN = 28 %, LIP = 19 %) were reached with increasing the light intensity to 192 ± 20 µmol photons m-2 s-1 on the 8th day of cultivation. The runs carried out under such optimum conditions, but using carbon dioxide from alcoholic fermentation, led to the following results: Xm = 3298 mg L-1, PX = 206 mg L-1 d-1, CLf = 4,0 mg g-1, PTN = 28 %, LIP = 17 %. Conclusively, the use of carbonic acid gas from alcoholic fermentation on A. platensis cultivation was found viable. It would be valuable to further study the influence of this industrial effluent gas on the metabolism and growth of such photosynthetic microorganism, in order to make it possible reaching cell concentration and productivity results as high as those obtained using pure carbon dioxide.
32

Heat Transfer and Flow in Solar Energy and Bioenergy Systems

Xu, Ben January 2015 (has links)
The demand for clean and environmentally benign energy resources has been a great concern in the last two decades. To alleviate the associated environmental problems, reduction of the use of fossil fuels by developing more cost-effective renewable energy technologies becomes more and more significant. Among various types of renewable energy sources, solar energy and bioenergy take a great proportion. This dissertation focuses on the heat transfer and flow in solar energy and bioenergy systems, specifically for Thermal Energy Storage (TES) systems in Concentrated Solar Power (CSP) plants and open-channel algal culture raceways for biofuel production. The first part of this dissertation is the discussion about mathematical modeling, numerical simulation and experimental investigation of solar TES system. First of all, in order to accurately and efficiently simulate the conjugate heat transfer between Heat Transfer Fluid (HTF) and filler material in four different solid-fluid TES configurations, formulas of an effective heat transfer coefficient were theoretically developed and presented by extending the validity of Lumped Capacitance Method (LCM) to large Biot number, as well as verifications/validations to this simplified model. Secondly, to provide design guidelines for TES system in CSP plant using Phase Change Materials (PCM), a general storage tank volume sizing strategy and an energy storage startup strategy were proposed using the enthalpy-based 1D transient model. Then experimental investigations were conducted to explore a novel thermal storage material. The thermal storage performances were also compared between this novel storage material and concrete at a temperature range from 400 °C to 500 °C. It is recommended to apply this novel thermal storage material to replace concrete at high operating temperatures in sensible heat TES systems. The second part of this dissertation mainly focuses on the numerical and experimental study of an open-channel algae culture raceway for biofuel production. According to the proposed flow field design of ARID-HV algal raceway, experiments and numerical simulation have been conducted to understand the enhancement of flow mixing in the flow field of ARID-HV raceway by cutting slots on top of the dam near the dead zones. A new method was proposed to quantitatively evaluate the flow mixing by using the statistics of temporal and spatial distribution of the massless fluid particles (centered in each cell at the inlet surface) in the raceway collecting the data of path-lines of fluid particles from CFD results. It is hoped that this method can be applied to assist the algal raceway flow field design as well as other engineering applications. The third part introduces the details about the construction work of a high temperature molten salt test loop. Because of the limited operating temperature of conventional synthetic oils, in order to obtain higher energy conversion efficiency, higher operating temperature is always desirable in a CSP plant which leads to the requirement of new generation of HTF. Currently, a halide salt eutectic mixture (NaCl-KCl-ZnCl₂) as a potential HTF for future CSP applications has been proposed by a multi-institute research team, led by University of Arizona. The thermophysical properties of the halide eutectic salt have been measured. However, this new developed halide eutectic salt has not been tested in a circulating loop at a high operating temperature for the measurement of heat transfer coefficient. It is a significant effort to build such a test system due to extremely high operating temperature. As a consequence, in the third part of this dissertation, details about the design of the lab-scale test system and all the equipment items will be introduced. The investigations included in this dissertation for the heat transfer and flow in solar energy and bioenergy systems are of particular interest to the renewable energy engineering community. It is expected that the proposed methods can provide useful information for engineers and researchers.
33

Voda v urbanizovaném prostředí Svratecký náhon ve městě Brně / Water in an Urbanized Environment Svratka Raceway

Pavlovský, Tomáš Unknown Date (has links)
The dissertation describes the historic development of watercourses in Brno territory focusing on the artificial canal Svratka raceway and the present state is described based on the available map data, preserved picture materials and photographic documentation of the present state. The work offers memories of several people from Brno who remember the artificial watercourse, these complete the picture of the Svratka raceway at the time of its extinction. The dissertation documents the present state of areas where the raceway used to run and on which it bordered. What attitude the twin towns of Brno - Leipzig and Graz - take, is outlined in the chapter Examples of Raceway and Natural Stream Reconstruction in Here and Abroad. The presented work should serve as a comprehensive source material for further study of Svratka raceway and further possible studies of arrangement of the areas where the raceway used to run and its - at least - partial reconstruction.
34

Nová nábřeží - skrytý potenciál Svitavského náhonu v Brně / New quay - hidden potential Svitava drive in Brno

Matějová, Pavla January 2009 (has links)
Bc. Pavla Matějová, Architecture and Urbanism, Department of Design V., Faculty of Architecture, Brno University of Technology 2009, 19 pages Diploma Thesis, Tutor doc. Ing. arch. Karel Havliš, Faculty of Architecture, Brno University of Technology The diploma thesis deals with an urban and architectural design of a stretch of post-industrial area along the Svitava raceway in Brno, specifically the locality in the area next to the municipal heating plant on Radlas and the former plant Mosilana in Křenová Street. The thesis main objective is to find the potential and capacity of the Svitava raceway concerning redevelopment and creation of new public areas, especially in the form of embankments designated for pedestrians. The design also focuses on redevelopment and finding new suitable functional utilization, in particular of the industrial buildings and premises of the former plant Mosilana. The theoretical part of the diploma thesis describes the urban development of the city, its history and the development of Brno region as well as rivers in its district. It examines and analyses the prerequisites of the area affecting the design. Complete description and specifications of the projected design are to be found here. The drawing part deals with the graphic analysis of the area as well as the concretization of prerequisites influencing the design and solves the complete urban design together with the designated local views of the area.
35

Voda ve veřejném prostoru Starého Brna / Water in Public Space of Staré Brno

Šerek, Jiří January 2011 (has links)
The aim of the project is to restore water features in public spaces of the oldest city quarter Old Brno, and also to strengthen the genius loci of this characteristic district by mention of defunct Svratka raceway. The main theme of the work will be combination of water management, urbanism and architecture with a special attention on cultivation of public spaces by application of linear water features.
36

Enhanced Biomass and Lipid Productivities of Outdoor Alkaliphilic Microalgae Cultures through Increased Media Alkalinity

Vadlamani, Agasteswar January 2016 (has links)
No description available.
37

200 MBPS TO 1 GBPS DATA ACQUISITION & CAPTURE USING RACEWAY

O’Connell, Richard 10 1900 (has links)
International Telemetering Conference Proceedings / October 27-30, 1997 / Riviera Hotel and Convention Center, Las Vegas, Nevada / For many years VME has been the platform of choice for high-performance, real-time data acquisition systems. VME’s longevity has been made possible in part by timely enhancements which have expanded system bandwidth and allowed systems to support ever increasing throughput. One of the most recent ANSI-standard extensions of the VME specification defines RACEway, a system of dynamically switched, 160 Mbyte/second board-to-board interconnects. In typical systems RACEway increases the internal bandwidth of a VME system by an order of magnitude. Since this bandwidth is both scaleable and deterministic, it is particularly well suited to high-performance, real-time systems. The potential of RACEway for very high-performance (200 Mbps to 1 Gbps) real-time systems has been recognized by both the VME industry and a growing number of system integrators. This recognition has yielded many new RACEway-ready VME products from more than a dozen vendors. In fact many significant real-time data acquisition systems that consist entirely of commercial-off-the-shelf (COTS) RACEway products are being developed and fielded today. This paper provides an overview of RACEway technology, identifies the types of RACEway equipment currently available, discusses how RACEway can be applied in high-performance data acquisition systems, and briefly describes two systems that acquiring and capturing real-time data streams at rates from 200 Mbps to 1 Gbps using RACEway.
38

Frequencias e formas de fornecimento de ração para tilápia do Nilo criada em sistema raceway / Feed frequency and ratio for Nile tilapia in raceway system

SANTOS, Janaína Gomes Araújo 20 August 2008 (has links)
Made available in DSpace on 2014-07-29T15:07:50Z (GMT). No. of bitstreams: 1 Dissertacao JanainaGomes.pdf: 323977 bytes, checksum: 872ea1e01b711a691d7746d206ac395e (MD5) Previous issue date: 2008-08-20 / The present research was carried out at Sector of Fish of the Goiás Federal University, between December the 2006 and May the 2007, which lasted for 127 days. Nile tilapia juveniles (Oreochromis niloticus), Supreme strain, with starter weight of 31.86 ± 1.75 g were randomly allotted in 32 tanks of 100 L of capacity each one in raceway system. The full water exchange of the tanks occurred in 30 min at the beginning. The fish were fed with extruded diet containing 36% of CP in pellets of 2-4 mm in diameter. By the average weight of 100 g, the fish were fed with extruded diet with 32% of CP in pellets of 4-6 mm in diameter until the end of the experiment. This assessment was performed to evaluate feed frequencies (2, 3, 4 and 5 times/day) and ratio (ad libitum and based on the percentage of the biomass weight - %PVBIO) on the productive performance, chemical composition, biometric indices, carcass and fillet yield and costs and profitability partial of Nile tilapia during the weight gain in the raceway system. The experimental design was composed by a completely randomized design in a factorial (4 x 2), with four repetitions, totalizing 32 experimental units. The performances body weight (BW), weight gain (WG), final biomass (FB), feed intake (FI), index of food intake (IF), apparent feed conversion ratio (AFCR), feed efficiency (FE), survival (S%), protein efficiency ratio (PER), specific growth ratio (SGR) and uniformity of the lot (U%) -; fillet weight (FW), carcass yield (CY), fillet yield(FY), biometric indices, and chemical composition fillet (total dry matter (TDM), moisture (MO), crude protein (CP), crude lipid (CL), ash) were the main evaluated parameters. The performance data were submitted to the analysis of variance and Duncan tests (5%), and the others to Tukey test (5%). Despite the quantity of food provided in the treatments, the main variables of water quality remained within the limit recommended for fish breeding. Better AFCR, FE and PER were reached for fish fed three times a day and greater PVBIO% for those ones fed twice daily ad libitum (P <0.05). The values of FBW, FL, FWG, FB, and FI were higher for fish fed four times a day (P <0.05), with the AFCR and PER values similar to those in fish fed three times a day. S%, SGR, CF and U% suffered no influence by the feeding frequency (P> 0.05). Only in IF differences on how to supply the ration (P <0.05) were observed. Fish fed four, five and three times a day had better average of FY, differing from those fed twice a day (P<0.05). The feeding frequency of less than five times had greater CY and VFI, but it did not differ from the other regimens. Difference in form of supply was observed only for RF, and the best average was reached in fish fed ad libitum. Regarding the chemical composition fillet, no differences in ashes were observed (P>0.05). The highest level of CL was found in three times of feeding frequency, which was statistical relevant (P<0.05) in comparison to the others. Interaction was observed for the variables TDM, MO and CP. The cost incidence (CI) was lower in three times a day of feeding frequency with feed supply based on %BW. The feeding frequency of 3 times per day ad libitum presented the best result concerning performance, and suggested lower cost with labor for juveniles of Nile tilapia cultivated in raceway tanks. / A pesquisa foi realizada no Setor de Piscicultura da Escola de Veterinária da Universidade Federal de Goiás, no período de dezembro de 2006 a maio de 2007, com duração de 127 dias. Foram utilizados juvenis de tilápia do Nilo (Oreochromis niloticus), linhagem Supreme, com peso médio inicial de 31,86 ± 1,75 g, distribuídos aleatoriamente em 32 caixas reguladas para 100 L adaptadas ao sistema raceway. A troca total de água das caixas, no início, ocorreu em 30min. Os peixes foram alimentados com ração extrusada contendo 36% de PB e grânulos com 2 a 4 mm de diâmetro até o peso médio aproximado de 100 g; em seguida, foram alimentados com ração extrusada 32% de PB com grânulos de 4 a 6 mm de diâmetro até o final do experimento. Objetivou-se determinar o efeito das frequências (2, 3, 4 e 5 vezes/dia) e formas de fornecimento da ração (à vontade e com base na porcentagem do peso da biomassa) sobre o desempenho produtivo, a composição bromatológica do filé, os índices biométricos, os rendimentos de carcaça e filé, e custos e rentabilidade parciais da tilápia durante a fase de engorda no sistema raceway, constituindo, assim, um delineamento inteiramente casualizado em esquema fatorial (4 x 2), com quatro repetições, totalizando 32 unidades experimentais. Foram assim avaliados: desempenho produtivo - peso (P), ganho de peso (GP), biomassa final (BF), consumo de ração (CR), índice de consumo alimentar (IA), conversão alimentar aparente (CAA), taxa de eficiência alimentar (TEA), taxa de eficiência protéica (TEP), taxa de crescimento específico (TCE), sobrevivência (S%), uniformidade do lote (U%) -; peso do filé (PF), rendimentos de carcaça (RC) e filé (RF), índice hepatosomático (IHS), índice gordura víscero-somático (IGVS) e composição bromatológica do filé (matéria seca total (MST), umidade (UM), proteína bruta (PB), extrato etéreo (EE), cinzas). Os dados de desempenho produtivo foram submetidos à análise de variância e teste Duncan (5%), e os demais ao teste Tukey (5%). Apesar da quantidade de alimento fornecido por tratamento, as principais variáveis de qualidade da água permaneceram dentro do limite recomendável para os peixes. Os valores de P, GP, BF, e CR foram maiores para os peixes arraçoados quatro, três e cinco vezes ao dia, respectivamente, diferindo de duas vezes ao dia (P<0,05). Foi observada interação significativa para IA, CAA, TEA e TEP. Observou-se melhor CAA, TEA e TEP para os peixes arraçoados três vezes ao dia pela %PVBIO e duas vezes ao dia à vontade (P<0,05). S%, TCE e U% não sofreram influência quanto à frequência alimentar (P>0,05). Os peixes arraçoados três, quatro e cinco vezes ao dia apresentaram melhor média de RF diferindo dos peixes arraçoados duas vezes (P<0,05). A frequência de cinco vezes apresentou menor RC e maior IGVS, porém não diferiu das demais. Foi observada diferença para forma de fornecimento apenas para RF, sendo a melhor média para os peixes arraçoados à vontade. Quanto à composição bromatológica, só não foram observadas diferenças (P>0,05) para Cinzas. O maior teor de EE foi encontrado na frequência de três vezes (P<0,05) diferindo das demais. Foi observada interação (P<0,05) para as variáveis MST, UM e PB. Quanto à avaliação econômica, a incidência de custo (IC) foi menor na frequência de três vezes ao dia com fornecimento de ração baseado na %PVBIO. Recomenda-se a frequência alimentar de 3 vezes/dia para juvenis de tilápia do Nilo até o abate por possibilitar menor gasto com mão de obra, melhores resultados para desempenho, com fornecimento de ração à vontade, até atingirem a saciedade aparente, quando cultivados em tanques raceways
39

Desempenho zootécnico de duas linhagens de Tilápia-do-Nilo sob diferentes densidades de estocagem em raceway / Performance of two nile tilapia strains in different stocking densities in raceway system

OLIVEIRA, Raquel Priscila de Castro 30 April 2010 (has links)
Made available in DSpace on 2014-07-29T15:13:43Z (GMT). No. of bitstreams: 1 Tese Raquel Priscila de Castro Oliveira.pdf: 2385507 bytes, checksum: 70f3aa3088e08bd364a210435717e331 (MD5) Previous issue date: 2010-04-30 / This study was developed in order to analyze productive performance, economic evaluation, bromotological composition of fish fillet, body components percentage and glucose level of two of Nile tilapia strains (chitralada and supreme) in three stocking densities (90, 120 and 150 fish/m3) in the raceway system. This work was carried out at the Fish Culture Sector from Universidade Federal de Goias. A total of 1,440 Nile tilapia fingerlings were produced in 24 polyethylene water tanks, adapted to raceway system. Each experimental unit had individual pipe for water supply and flow was regulated to allow total exchange every 30 minutes, regardless of stocking density. The animals were fed three times a day with commercial extruded ration, ad libitum, seven days a week. The design was completely randomized in a 2 x 3 factorial arrangement and four replications. The results were submitted to variance analysis and, in cases of statistical variance, to the Tukey test (5%). After the all variables analysis, it was concluded that both strains presented positive characteristics for production in Goias State in raceway system. Supreme strain, in higher water density, is the one recommended by this study due to greater profitability, and to positive performance aspects. / Esse trabalho foi desenvolvido com o intuito de avaliar o desempenho produtivo, a avaliação econômica, a composição bromatológica do filé, o percentual de componentes do corpo, e a glicemia de duas linhagens comerciais de tilápia-do-Nilo, a chitralada e a supreme submetidas a três densidades de estocagem 90, 120 e 150 peixes/m3 em sistema de alto fluxo de água. O estudo foi realizado no Setor de Piscicultura da Universidade Federal de Goiás. No total, 1440 alevinos de tilápia-do-Nilo foram estocados em 24 caixas d água de polietileno adaptadas ao sistema raceway. Cada unidade experimental era provida de tubulação individual para abastecimento e a vazão foi regulada para troca total a cada 30 minutos, independente da densidade de estocagem. Biometrias mensais foram realizadas e coletados dados para a avaliação. Os animais foram alimentados com ração comercial extrusada, até a saciedade momentânea, sete dias por semana. O delineamento utilizado foi inteiramente ao acaso em esquema fatorial 2x3 e quatro repetições. As médias dos resultados encontrados foram submetidos a análise de variância e, em caso de diferença estatística, ao teste de comparação de médias Tukey (5%). Após a análise de todas as variáveis concluiu-se que ambas as linhagens apresentaram características favoráveis de produção no Estado de Goiás em sistema raceway. A linhagem supreme, na maior densidade de estocagem, foi a recomendada após esse estudo devido a maior rentabilidade e aspectos positivos no desempenho.
40

Výzkum a vývoj ložisek pro trakční motory / Research and development of bearings for traction motors

Prášilová, Alena January 2011 (has links)
This master’s thesis deals with construction design of cylindrical roller bearing for traction motor and design of life test tool for designed bearing. At the thesis beginning there is an overview of new trends in design of cylindrical roller bearing, according to new trends is designed a new construction design of cylindrical roller bearing. Other part of thesis is strain stress analysis, which assesses an optimal inclination of collar faces and optimal raceway modification of hybrid bearing rings. At the end life test will be analyzed.

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