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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.
11

AVALIAÇÃO DO CONFORTO TÉRMICO DE UM APRISCO PARA A CIDADE DE SANTA MARIA/RS / COMFORT ASSESSMENT THERMAL ONE BUILDING FOR SANTA MARIA CITY / RS

Santos, Eudes Vinícius dos 21 October 2015 (has links)
Sheep production has always played a fundamental role in society throughout history, and it has been highlighted as an important economic activity in Rio Grande do Sul, Brazil. Rio Grande do Sul presents climatic peculiarities that in some situations impose a condition of thermal discomfort in animals, generating heat stress, which is one of the main limiting factors of animal production. Seeking alternatives that provide better thermal comfort for confined animals and a consequent greater production is essential. This study was carried out with sheep and lambs confined in a fold (fenced enclosure area) at Universidade Federal de Santa Maria and aimed to evaluate the thermal comfort that the fold gives animals in a typical winter and summer day. We assessed environmental variables such as air temperature, radiant temperature, relative humidity, and air velocity. Subsequently, the Black Globe and Humidity Index (BGHI) and Thermal Comfort Index (TCI) were utilized to evaluate animal thermal comfort. Additionally, rectal temperature, respiratory rate, and skin temperature of the animals as well as thermographic images of the wool surface of the (fur) animals and fold were evaluated. Based on data gathering and calculation of the indices, it was possible to observe that the animals were in thermal discomfort for most part of the experiment. For the typical winter period, no reference values of BGHI and TCI were found; however, some animals had a rectal temperature of 35.5 ° C, which is below normal levels. The fold had thermal cushioning below 28%, imposing internal temperatures of 7.8 ° C in the animals. This temperature is out of the thermal comfort zone (TCZ), which lies between 25 and 30 ° C for newborns and between 15 and 30 ° C for adult animals, being close to 6 ° C, which is considered lower critical temperature (TCL). For the typical summer period, the building had a heat buffer below 10% and it was possible to assess comfort using BGHI and TCI. During the morning, BGHI was below 74, which represents thermal comfort values. On the other hand, the fold in the afternoon presented BGHI ranging between 74 and 79, which represents state of alert. As a conclusion, the fold studied does not provide thermal comfort for animals in most of the typical winter and summer period. As a consequence, it requires constructive improvements to ensure that animals are provided with comfort and well-being so that they reach their maximum productive and reproductive performance. / A ovinocultura exerce papel fundamental na história e na pecuária do Rio Grande do Sul e vem se destacando como importante atividade econômica no Brasil. O Rio Grande do Sul, por sua vez, apresenta peculiaridades climáticas que impõem aos animais, em algumas situações, uma condição de desconforto térmico, gerando o estresse térmico, que é um dos principais fatores limitantes da produção animal. Portanto, torna-se imprescindível a busca por alternativas de conforto térmico que proporcionem bem estar aos animais e que gerem maior potencial na sua produção, principalmente em ambientes protegidos. Pretendeu-se, com este trabalho, avaliar o conforto térmico que a edificação, denominada aprisco (instalação para ovinos) proporciona aos animais (cordeiros e borregos) confinados no laboratório de ovinocultura da Universidade Federal de Santa Maria, para um dia típico de inverno e um dia típico de verão, por meio do levantamento das variáveis ambientais, tais como temperatura do ar, temperatura radiante, umidade relativa, velocidade do ar e posterior cálculo do Índice de Temperatura de Globo Negro e Umidade (ITGU) e do Índice de Conforto Térmico (ICT), ambos índices para avaliar o conforto térmico animal. Também foram realizadas a coleta da temperatura retal, da frequência respiratória e da temperatura da epiderme dos animais, bem como o levantamento de imagens termográficas da superfície da lã (vélo) dos animais e do aprisco. Foi possível avaliar, com base nos levantamentos de dados e no cálculo dos índices, que os animais estavam em desconforto térmico na maior parte do experimento. Para o período típico de inverno, não foram encontrados valores de referência dos índices ITGU e ICT; no entanto, alguns animais apresentaram temperatura retal de 35,5°C, abaixo do normal. A edificação (aprisco) teve um amortecimento térmico abaixo de 28%, impondo aos animais, temperaturas internas de 7,8°C, isto é, fora da zona de conforto térmico (ZCT), que se encontra entre 25 e 30°C para animais recém-nascidos e entre 15 e 30°C para animais adultos, estando mais próximas de 6°C, considerada temperatura crítica inferior (TCI). Para o período típico de verão, a edificação apresentou amortecimento térmico abaixo de 10% e foi possível avaliar o conforto através dos índices, ITGU e ICT. Durante o período da manhã, o ITGU ficou abaixo de 74, o que representa valores de conforto térmico. Já no período da tarde, as instalações apresentaram ITGU compreendidos entre 74 e 79, o que significa situação de alerta. Portanto, ao fim do experimento, foi constatado que a edificação (aprisco) não proporciona conforto térmico aos animais na maior parte do período típico de inverno e verão. Por fim, entendeu-se que a edificação existente precisa de melhorias construtivas para que os animais disponham de conforto e bem estar para que atinjam seu máximo rendimento produtivo e reprodutivo.
12

Equalização e segmentação de imagens termográficas aplicadas à metodologia de inspeção de isoladores poliméricos.

OLIVEIRA, Renata Garcia Dutra de. 17 April 2018 (has links)
Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2018-04-17T16:49:57Z No. of bitstreams: 1 RENATA GARCIA DUTRA DE OLIVEIRA – DISSERTAÇÃO (PPGEE) 2017.pdf: 2837305 bytes, checksum: 244c93af337ec0f89cf4eb7ae057d905 (MD5) / Made available in DSpace on 2018-04-17T16:49:57Z (GMT). No. of bitstreams: 1 RENATA GARCIA DUTRA DE OLIVEIRA – DISSERTAÇÃO (PPGEE) 2017.pdf: 2837305 bytes, checksum: 244c93af337ec0f89cf4eb7ae057d905 (MD5) Previous issue date: 2017-03-31 / Capes / A análise da variação de temperatura ao longo do isolador, por meio da termografia, pode consistir em um dos métodos mais eficazes de avaliação de isoladores em serviço, pois considera o efeito combinado da poluição, do estresse elétrico, defeitos internos e das condições ambientais. No entanto, analisar apenas de modo visual imagens termográficas é difícil e, muitas vezes, apenas os engenheiros especializados são capazes de fazer julgamentos corretos. Neste trabalho foi desenvolvida uma técnica para análise de imagens termográficas baseada em expansão não-linear de sinais, equalização de histogramas e análise de componentes principais com o objetivo de auxiliar no diagnóstico do nível de degradação de isoladores poliméricos. O processamento digital das imagens termográficas permitiu a obtenção dos valores de temperatura que indicam o comportamento térmico dos isoladores sob inspeção. Ensaios em laboratório foram realizados com isoladores poliméricos de 230 kV, com diferentes níveis de degradação, com a finalidade de captar imagens utilizando uma câmera de detecção de radiação infravermelha. Os resultados evidenciam a eficiência da metodologia desenvolvida, atuando de forma semiautomática no processamento digital de imagens termográficas, para obtenção do perfil térmico dos isoladores inspecionados. Com base nos produtos do processamento digital das imagens termográficas, tem-se uma melhor avaliação dos níveis de degradação em que se encontram os isoladores, além de auxiliar de forma eficiente a tomada de decisão para a classificação dos seus estados operacionais. / The analysis of the temperature variation along the insulator through thermography can be one of the most effective methods of evaluating insulators in service, for it considers the combined effect of pollution, electrical stress, internal defects and environmental conditions. However, analyses based only on visual inspection of images are not enough. In fact, only specialized engineers are able to make correct judgments. In this work a computational routine was developed, based on the digital image processing. The routine utilizes the signal nonlinear expansion technique, histogram equalization and principal component analysis. The digital processing of the thermographic images is used to obtain the temperature values that indicate the thermal behavior of the insulators under inspection. Laboratory tests were performed with 230 kV polymeric insulators with different levels of degradation in order to capture images using an infrared radiation detection camera. The results demonstrate the efficiency of the digital thermographic imaging technique to obtain the thermal profile of the insulators inspected. Based on the products of the digital processing of the thermographic images, we have a better evaluation of the degradation levels of the insulators, besides efficiently support to the classification of the operational states of the insulators.
13

Uplatnění energie obnovitelných zdrojů v budovách / The application of renewable energy in buildings

Panovec, Jan January 2015 (has links)
The aim of this diploma thesis is to understand the functioning of heating and cooling systems in an administrative building built in passive standard using a renewable energy source. The thesis includes theoretical findings of heat pumps and designing the heating systems. The experimental part contains an analysis of working of heating and cooling systems in selected rooms in assigned building, which includes an experimental measurement of selected quantities and a thermographic measurement. In the last part of the thesis a comparison of measured and simulated values using simulation software was done.
14

Snižování vibrací a akustických emisí pohonných jednotek aplikací virtuálního motoru / Vibration and Acoustic Emission Reduction of Powertrains using Virtual Engine

Svída, David January 2011 (has links)
Doctoral thesis deals with combustion engine cranktrain vibrations and vibration analysis methods. The work applies new computational models aimed at powertrain vibration decrease. The computational models can be used in the first stages of powertrain development. Temperature dependences of the rubber shear modulus and loss factor characteristic are found by response analysis of the free damped vibrations in the first part of the thesis. Viscoelastic model parameters of two dampers with different rubber hardness are calculated using optimization methods. Temperature distribution inside the rubber part during the harmonic oscillation is calculated with the knowledge of previous values. Computational models together with a user interface are assembled in Matlab/Simulink software tool. Computational model results of the viscoelastic rubber damper are verified by measurements on a prototype diesel engine in the whole operating engine speed range. Torsional vibrations of the crankshaft with torsional damper are measured by POLYTEC laser rotational tools. The temperature distribution on the damper surface is obtained by Infratec VarioCAM thermographic system. Combustion pressures in the cylinder are measured by SMETEC Combi indication tools. Both the temperature distributions and combustion pressures are used for computational purposes. All the measurement procedures are described also in the thesis.
15

Analyse de la topologie des flammes prémélangées swirlées confinées / Analysis of the topology of premixed swirl-stabilized confined flames

Guiberti, Thibault 04 February 2015 (has links)
Ce travail porte sur la stabilisation de flammes prémélangées et swirlées de mélanges combustibles méthane/hydrogène/air avec différents taux de dilution d’azote et de dioxyde de carbone. Une tige centrale permet de stabiliser des flammes pour de faibles nombres de swirl. Le sommet de la flamme interagît éventuellement avec les parois de la chambre de combustion. L’objectif ces travaux est d’améliorer la connaissance des mécanismes qui gouvernent la stabilisation et la topologie de ces flammes. Ces travaux démontrent que le nombre de swirl, la composition du mélange combustible, la géométrie de la chambre de combustion ainsi que les conditions aux limites thermiques ont une grande influence sur la forme prise par la flamme. Le dispositif expérimental permet de modifier la forme et la taille de la chambre de combustion, le diamètre du tube d’injection et le nombre de swirl. Des conditions opératoires propices aux transitions de forme de flamme sont ensuite étudiées pour différentes configurations de brûleur. Une caractérisation expérimentale fouillée d’un point de fonctionnement est réalisée grâce à la Fluorescence Induite par Laser sur le radical Hydroxyle (OH-PLIF), la Vélocimétrie par Images de Particules (PIV) et la Phosphorescence Induite par Laser de phosphores sensibles à la température (LIP). Une base de donnée de l’écoulement et des conditions aux limites associées est obtenue sans et avec combustion. Les mécanismes qui contrôlent les transitions de formes de flamme sont ensuite analysés lorsque la flamme interagit avec les parois de la chambre de combustion. L’influence de la composition du mélange combustible, de la vitesse débitante et du nombre de swirl est caractérisée et il est démontré que la transition d’une flamme en V vers une flamme en M est déclenchée par un retour de flamme dans la couche limite le long d’une des parois latérales de la chambre de combustion. Les nombres sans dimension contrôlant ces transitions sont identifiés et un modèle de prévision de la forme de ces flammes est développé. La physique déterminant les transitions de forme de flammes est différente lorsque celles-ci n’interagissent pas avec les parois de la chambre de combustion. En utilisant le signal de chimiluminescence OH* et la OH-PLIF, il est montré que la teneur en hydrogène dans le combustible a une grande influence sur la forme de flamme. L’utilisation de la LIP et de thermocouples a également permis de montrer que les conditions aux limites thermiques jouent un rôle prépondérant sur la forme de flamme. Les effets combinés de l’étirement et des pertes thermiques sont examinés par l’utilisation conjointe de la PIV et de la OH-PLIF. Il est montré que les limites d’extinction de flammes pauvres prémélangées sont réduites par les pertes thermiques et que la transition d’une flamme en M vers une flamme en V est consécutive à l’extinction du front de flamme situé dans la couche de cisaillement externe du jet soumis à un étirement trop important. Ces expériences sont complétées par une analyse de la dynamique de ces flammes. Des modulations de la vitesse débitante à basse fréquence et à haute amplitude modifient la forme de flamme. La stabilisation de flammes CH4/H2/air diluées par du N2 ou du CO2 est finalement examinée. La zone de recirculation produite par la tige centrale permet d’alimenter la base de la flamme avec des gaz brûlés chauds et de stabiliser des flammes fortement diluées. Augmenter la fraction molaire de diluant dans le combustible réduit l’intensité de lumière émise par le radical OH*. Il est également montré que la composition du diluant a un impact sur le champ de température des gaz brûlés et des surfaces de la chambre de combustion. La dilution par du CO2 augmente les pertes thermiques par rayonnement des gaz brûlés. Cela réduit l’efficacité de la chambre de combustion équipée de quatre parois transparentes. [...] / This work deals with the stabilization of premixed turbulent swirling flames of methane/hydrogen/air combustible mixtures with different dilution rates of nitrogen and carbon dioxide. A central bluff body helps stabilizing the flames at low swirl numbers. The flame tip eventually impinges the combustor peripheral wall. The general objective is to gain understanding of the mechanisms governing the stabilization and the topology of these flames. It is found that the swirl number, the combustible mixture composition, the geometry of the combustor, and the thermal boundary conditions have a strong impact on the shape taken by these flames. The experimental setup used to characterize flames topologies is first described. Flames prone to topology bifurcations are selected and are studied for different arrangement of the combustor when the combustion chamber shape and size, the injection tube diameter, and swirl number are varied. One operating condition is fully characterized under non-reactive and reactive conditions using Planar Hydroxyl Laser Induced Fluorescence (OH-PLIF), Particle Imaging Velocimetry (PIV), and Laser Induced Phosphorescence of thermographic phosphors (LIP) to generate a detailed database of the flow and the corresponding boundary conditions. An analysis is then conducted to understand the mechanisms controlling shape bifurcations when the flame interacts with the combustor peripheral wall. Effects of the combustible mixture composition, the bulk flow velocity, and the swirl number are analyzed. It is shown that the transition from a V to an M flame is triggered by a flashback of the V flame tip in the boundary layer of the combustor peripheral wall. Dimensionless numbers controlling these transitions are identified and a simplified model is developed to help the prediction of the flame shapes. The physics of these shape bifurcations differs when the flame does not interact with the combustor wall. The large influence of the hydrogen enrichment in the fuel on the flame shape is analyzed using flame chemiluminescence and OH-PLIF. LIP and thermocouple measurements demonstrate that the thermal boundary conditions still have a strong impact on the flame topology. The combined effects of strain and heat losses are investigated using joint OH-PLIF and PIV experiments. It is shown that flammability limits of premixed flames are reduced due to heat losses and the transitions from M to V shaped flames is consecutive to localized extinctions of flame front elements located in the outer shear layer of the jet flow that are submitted to large strain rates. These experiments are completed by an analysis of the dynamics of methane/hydrogen/air flames. It is shown that low frequency and high amplitude velocity modulations generated by a loudspeaker alter the shape taken by these flames. The stabilization of methane/hydrogen/air flames diluted by nitrogen and carbon dioxide is finally examined. It was possible to stabilize swirled flames featuring important dilution rates due to the presence of the bluff body, installed on the axis of the injection tube. The recirculation zone behind this element supplies hot burnt gases to the flame anchoring point. Using OH* chemiluminescence imaging, it is shown than increasing the molar fraction of diluent in the fuel reduces the light emission from excited OH* radicals. The influence of dilution on the flame chemistry is emphasized with experiments conducted at a fixed thermal power and fixed adiabatic flame temperature. It is also demonstrated that the composition of the diluent has a strong influence on the temperature field of the burnt gases and of the combustor wall surfaces. Dilution with carbon dioxide increases radiative heat losses from the burnt gases in comparison to dilution with nitrogen. This penalizes the combustor efficiency equipped with four transparent quartz walls. [...]
16

Energetický posudek a průkaz energetické náročnosti budovy / Energy assessment and certificate of energy performance of buildings

Bidmonová, Renata January 2020 (has links)
The aim of the diploma thesis is to evaluate the energy assessment and elaboration of energy performance certificates of the building. The building is an apartment building in Vítkov. The theoretical part deals with centralized heat supply. The calculation part contains a more detailed description of individual relationships and calculation procedures that are used to process energy performance certificates of the building. Furthermore, proposals for measures to improve the energy performance of buildings. In this part there is also a proposal of individual equipment of the new boiler room and thermographic measurement. In the project part there is an energy assessment assessing the building in two variants with individual heat sources. The evaluation is carried out from an energy, economic and environmental aspect.
17

Energetický posudek / Energy Assessment

Březina, Jan January 2016 (has links)
The first part of the final thesis is focused on the use of thermovision for diagnosing defects and failures in building industry. Documented history, physical principles and conditions for the measuring of thermographic camera are described in this part. Thermal images of the object described below were used for demonstrating the defects. The second part is dedicated to the elaborated energy assessment for a nine-storey slab block building. In total, there are five energy economic measures developed for the building. Three of those are of structural character and two of those are for building equipment. There are two variants designed based on the measures, one of which is recommended and evalu-ated. The final section is focused on the measurement of slab block building indoor environment (CO2, air temperature, relative humidity, dew point) and its assessment in concern with the current legislation.

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