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Gravure offset printing for fabrication of electronic devices and integrated components in LTCC modulesLahti, M. (Markku) 30 September 2008 (has links)
Abstract
The thesis is concerned with the development of gravure-offset-printing and low temperature co-fired ceramic (LTCC) technologies for the miniaturisation of electronic devices and components. The development work has been verified by several applications.
Several aspects of gravure-offset-printing have to be optimised in order to make it suitable for fine-line printing and these have been addressed in the study with a focus on the printing inks and plates. Gravure-offset-printing inks were developed from commercial thick-film pastes. The effects of different ink characteristics on some properties of conductor lines, such as line width and resistivity, were studied. The dependence of the conductor lines on the quality of the engravings in the printing plates was also studied. The narrowest line widths obtained were about 30 μm with an accuracy of ±5 μm.
Various LTCC compositions and processing steps involved in the production of integrated electronic devices, and the properties of several fabricated devices are discussed. The devices include inductors, band-pass filters and resistors for the 1–2 GHz frequency range. Miniaturisation has been the main focus of attention. For example, the integration of high-permittivity tapes in addition to low-permittivity tapes has made the miniaturisation of filter structures possible. Compatibility between these tapes during firing was found to be good.
LTCC technology was further developed by adapting a modified LTCC-on-metal (LTCC-M) approach. A traditional way of guiding heat away from a component is to place a heat-sink under the component and utilise thermal vias and solder balls. In this study high- and low-permittivity tapes were attached directly on a heat-sink. Different heat-sink options were evaluated and the best performance was achieved with an AlN heat-sink which was deposited by screen-printing a Au layer on it. High-power chips were attached directly on the heat-sink through cavities in the LTCC tapes. This approach also restricted the shrinkage of the LTCC tapes. The fabricated test structures and components proved the viability of the approach although the compatibility between the pastes and tapes was not optimal.
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Expressão gênica de proteínas de choque térmico como marcador molecular de termotolerância em vacas Nelore / Gene expression of heat shock proteins as molecular marker of thermotolerance in Nellore cowsHooper, Henrique Barbosa 08 July 2015 (has links)
Objetivou-se com este estudo compreender as dinâmicas das temperaturas corporais em fêmeas da raça Nelore, e relacionar os aspectos fisiológicos da termorregulação com as respostas celulares pela expressão de proteínas de choque térmico. O projeto foi desenvolvido no Laboratório de Biometeorologia e Etologia, da Faculdade de Zootecnia e Engenharia de Alimentos da Universidade de São Paulo, Pirassununga-SP. Foram utilizadas 20 vacas Nelore pluríparas, cíclicas, mantidas em sistema de pastejo. O período experimental precedeu a estação de monta de 2013 e terminou na inseminação artificial. Para classificar os animais quanto ao gerenciamento de calor foi monitorada a temperatura vaginal durante seis dias por meio de 16 data loggers (n=16). Com o intuito de melhor compreender o gerenciamento de calor, outras respostas fisiológicas, nomeadamente temperatura retal, caudal, ocular, frequência respiratória e taxa de sudação foram colhidas durante os quatro dias finais do monitoramento da temperatura vaginal. Para expressão gênica relativa colheram-se amostras de sangue (n=20). Foram realizados choques térmicos in vitro a 38ºC, 40ºC e 42ºC por duas horas. Após tratamento térmico obteve-se o pellet de leucócitos para posterior extração do RNA pelo método TRIzol. Foram escolhidas 10 vacas com os melhores resultados de concentração de RNA, 5 pertencentes ao grupo de vacas eficientes quanto ao gerenciamento de calor, e 5 não eficientes (n=10). A RT-PCR foi realizada com o kit SuperScript III. A reação polimerase em cadeia em tempo real (qPCR) ocorreu no aparelho StepOnePlus® Applied Biosystem utilizando como marcador fluorescente o SYBR® Green para os genes alvo validados HSPA1A, HSPD1, HSP90AA1, HIF1A e endógenos ACTB, RPL15 e PPIA. Os dados foram analisados por ANOVA, regressão e correlação do SAS 9.2. As vacas foram classificadas em eficientes e não eficientes por meio de coeficientes angulares, advindos da regressão das temperaturas vaginais durante períodos de ganho e perda de calor. As vacas eficientes apresentaram menores temperaturas retais 37,65ºC (P<0,01) e maior taxa de sudação 528,73 g. m-². h-¹ (P<0,06). A nível celular, o aumento programado in vitro da temperatura não aumentou quantidade de transcritos, promovendo manutenção à 38ºC e 40ºC e declínio à 42ºC. A ordem decrescente da abundância de transcritos foi HSPA1A, HSPD1 e HSP90AA1. Pode-se concluir que vacas Nelore com diferentes gerenciamentos de calor apresentam respostas termorregulatórias diferentes. A HSPA1A apresentou a maior abundância de transcritos sendo considerada como marcador molecular para termotolerância, por ser a mais sensível à temperatura e bem conservada. Não foi observado diferença nas expressões gênicas relativas das proteínas de choque térmico entre os animais classificados quanto ao gerenciamento de calor. / The aim of this study was to understand the dynamics of body temperatures in Nellore females, and relate the physiological aspects of thermoregulation with cellular responses by the expression of heat shock proteins. The project was developed in Biometeorology and Ethology Laboratory, Faculty of Animal Science and Food Engineering, University of São Paulo, Pirassununga-SP. Were used 20 Nellore pluriparous cows, cyclical, kept in grazing system. The experimental period preceded the 2013\' breeding season and ended up in artificial insemination. To classify animals in relation to heat management the vaginal temperature was monitored for six days through 16 data loggers (n=16). In order to better understand the heat management, other physiological responses, including rectal, tail and eye temperatures, respiratory rate and sweating rate were taken during the final four days of vaginal temperature monitoring. For gene expression was harvested blood samples (n=20). in vitro heat shocks were performed at 38ºC, 40ºC and 42ºC during two hours. After the heat treatment was obtained the leukocyte pellet for later RNA extraction by TRIzol method. Ten cows were chosen with the best RNA concentration results, five belonging to the group of cows efficient on heat management and five inefficient (n = 10). RT-PCR was performed with SuperScript III kit. The real-time polymerase chain reaction (qPCR) occurred in StepOnePlus® Applied Biosystems instrument using the SYBR® Green as fluorescent marker to the target validated genes HSPA1A, HSPD1, HSP90AA1, HIF1A and the endogenous ACTB, RPL15 and PPIA. Data were analyzed using ANOVA, regression and correlation SAS 9.2. The cows were classified as efficient and inefficient through angular coefficients, derived from regression of vaginal temperatures for the gain and heat loss periods. Efficient cows had lower rectal temperature 37.65ºC (P<0.01), higher sweating rate 528.73 g. m ². h-¹ (P<0.06). At cellular level, the increase of in vitro programmed temperature has not increased the transcripts amount, promoting the maintenance at 38ºC and 40ºC and decline at 42ºC. The decreasing order of transcripts amount was HSPA1A, HSPD1 and HSP90AA1. It can be concluded that Nellore cows with different heat managements has different thermoregulatory responses. The HSPA1A showed the highest transcripts abundance being considered as a molecular marker for thermotolerance, for being more sensitive to temperature and better conserved. There was no difference in gene expression for heat shock proteins between animals classified by heat management.
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Expressão gênica de proteínas de choque térmico como marcador molecular de termotolerância em vacas Nelore / Gene expression of heat shock proteins as molecular marker of thermotolerance in Nellore cowsHenrique Barbosa Hooper 08 July 2015 (has links)
Objetivou-se com este estudo compreender as dinâmicas das temperaturas corporais em fêmeas da raça Nelore, e relacionar os aspectos fisiológicos da termorregulação com as respostas celulares pela expressão de proteínas de choque térmico. O projeto foi desenvolvido no Laboratório de Biometeorologia e Etologia, da Faculdade de Zootecnia e Engenharia de Alimentos da Universidade de São Paulo, Pirassununga-SP. Foram utilizadas 20 vacas Nelore pluríparas, cíclicas, mantidas em sistema de pastejo. O período experimental precedeu a estação de monta de 2013 e terminou na inseminação artificial. Para classificar os animais quanto ao gerenciamento de calor foi monitorada a temperatura vaginal durante seis dias por meio de 16 data loggers (n=16). Com o intuito de melhor compreender o gerenciamento de calor, outras respostas fisiológicas, nomeadamente temperatura retal, caudal, ocular, frequência respiratória e taxa de sudação foram colhidas durante os quatro dias finais do monitoramento da temperatura vaginal. Para expressão gênica relativa colheram-se amostras de sangue (n=20). Foram realizados choques térmicos in vitro a 38ºC, 40ºC e 42ºC por duas horas. Após tratamento térmico obteve-se o pellet de leucócitos para posterior extração do RNA pelo método TRIzol. Foram escolhidas 10 vacas com os melhores resultados de concentração de RNA, 5 pertencentes ao grupo de vacas eficientes quanto ao gerenciamento de calor, e 5 não eficientes (n=10). A RT-PCR foi realizada com o kit SuperScript III. A reação polimerase em cadeia em tempo real (qPCR) ocorreu no aparelho StepOnePlus® Applied Biosystem utilizando como marcador fluorescente o SYBR® Green para os genes alvo validados HSPA1A, HSPD1, HSP90AA1, HIF1A e endógenos ACTB, RPL15 e PPIA. Os dados foram analisados por ANOVA, regressão e correlação do SAS 9.2. As vacas foram classificadas em eficientes e não eficientes por meio de coeficientes angulares, advindos da regressão das temperaturas vaginais durante períodos de ganho e perda de calor. As vacas eficientes apresentaram menores temperaturas retais 37,65ºC (P<0,01) e maior taxa de sudação 528,73 g. m-². h-¹ (P<0,06). A nível celular, o aumento programado in vitro da temperatura não aumentou quantidade de transcritos, promovendo manutenção à 38ºC e 40ºC e declínio à 42ºC. A ordem decrescente da abundância de transcritos foi HSPA1A, HSPD1 e HSP90AA1. Pode-se concluir que vacas Nelore com diferentes gerenciamentos de calor apresentam respostas termorregulatórias diferentes. A HSPA1A apresentou a maior abundância de transcritos sendo considerada como marcador molecular para termotolerância, por ser a mais sensível à temperatura e bem conservada. Não foi observado diferença nas expressões gênicas relativas das proteínas de choque térmico entre os animais classificados quanto ao gerenciamento de calor. / The aim of this study was to understand the dynamics of body temperatures in Nellore females, and relate the physiological aspects of thermoregulation with cellular responses by the expression of heat shock proteins. The project was developed in Biometeorology and Ethology Laboratory, Faculty of Animal Science and Food Engineering, University of São Paulo, Pirassununga-SP. Were used 20 Nellore pluriparous cows, cyclical, kept in grazing system. The experimental period preceded the 2013\' breeding season and ended up in artificial insemination. To classify animals in relation to heat management the vaginal temperature was monitored for six days through 16 data loggers (n=16). In order to better understand the heat management, other physiological responses, including rectal, tail and eye temperatures, respiratory rate and sweating rate were taken during the final four days of vaginal temperature monitoring. For gene expression was harvested blood samples (n=20). in vitro heat shocks were performed at 38ºC, 40ºC and 42ºC during two hours. After the heat treatment was obtained the leukocyte pellet for later RNA extraction by TRIzol method. Ten cows were chosen with the best RNA concentration results, five belonging to the group of cows efficient on heat management and five inefficient (n = 10). RT-PCR was performed with SuperScript III kit. The real-time polymerase chain reaction (qPCR) occurred in StepOnePlus® Applied Biosystems instrument using the SYBR® Green as fluorescent marker to the target validated genes HSPA1A, HSPD1, HSP90AA1, HIF1A and the endogenous ACTB, RPL15 and PPIA. Data were analyzed using ANOVA, regression and correlation SAS 9.2. The cows were classified as efficient and inefficient through angular coefficients, derived from regression of vaginal temperatures for the gain and heat loss periods. Efficient cows had lower rectal temperature 37.65ºC (P<0.01), higher sweating rate 528.73 g. m ². h-¹ (P<0.06). At cellular level, the increase of in vitro programmed temperature has not increased the transcripts amount, promoting the maintenance at 38ºC and 40ºC and decline at 42ºC. The decreasing order of transcripts amount was HSPA1A, HSPD1 and HSP90AA1. It can be concluded that Nellore cows with different heat managements has different thermoregulatory responses. The HSPA1A showed the highest transcripts abundance being considered as a molecular marker for thermotolerance, for being more sensitive to temperature and better conserved. There was no difference in gene expression for heat shock proteins between animals classified by heat management.
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Heat-pipes in electric machines : Heat management in electric traction motorsOlofsson, Anton January 2022 (has links)
The world is continually changing towards more energy efficient alternatives and less pollution. For the traction market, electric powertrains have become the go-to method, superior to both steam and diesel-electric hybrid systems. For subways and trams the natural development now is towards smaller motors with high power output, the goal is to use as much space as possible for the passengers and keep the performance of a larger motor setup. One problem with increasing the power density of the motors is that the accumulated heat from losses also increases per volume. All motors have different efficiency and different limits on temperatures in different parts. For this project a closed, self-ventilated traction motor with axis height 250mm (CSV250) was evaluated. The motor has an input power just above 140kW and the identified limiting factor is the temperature of the bearings, specifically the front bearing located at the fan side of the motor. An already existing and partly validated ANSYS MotorCAD model was used for full system overview and as a guide to build a COMSOL Multiphysics model of the motor rotor. The COMSOL model could be effectively changed to represent different configurations of the solution. The COMSOL solver is based on the finite element method, FEM, whereas the MotorCAD model is built as a thermal network with lumped parameter method, LPM. The proposed solution to the high temperature is implementation of heat-pipes in strategic positions. This project only contains evaluation of heat-pipes positioned in the center of the shaft deployed in three different configurations: a short heat-pipe transferring heat from the bearing to the fan, a long heat-pipe transferring heat from the active rotor parts to the fan and a long heat-pipe similar to previous case but with the heat-pipe insulted at the bearing section. The simulations yield performance specifications for the solution design that will give the expected result, complemented with theory this can then give the full appliable solution to the specified problem. For the short heat-pipe case a decrease in temperature form 116.5 to 96.5°C was achieved in the front bearing by increasing the heat-transfer from the bearing towards the fan with 84.4W. This is well under the preferred temperature of maximum 110°C. In the long heat-pipe case a total of 360W was dispersed through the fan and this lowered the highest temperature point in the rotor from 172.2 to 160.8°C but with the negative effect of increasing the temperature of the front bearing. In the third case the insulation of the long heat-pipe in the bearing section managed to lower this increased temperature from 130.4 to 122.4°C while 360W were still transferred through to the fan. This is under the absolute maximum at 130°C but over 110°C. The results point towards the possibility to increase power density and keeping temperatures manageable using heat-pipes but further work and experiments is needed to prov the concept.
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Bio-Inspired Synthetic Melanin-Based Structural Colors and Thermally Responsive NanocompositesEcheverri, Mario 28 November 2021 (has links)
No description available.
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Temperature Influence and Heat Management Requirements of Microalgae Cultivation in PhotobioreactorsMehlitz, Thomas Hagen 01 February 2009 (has links) (PDF)
Microalgae are considered one of the most promising feedstocks for biofuel production for the future. The most efficient way to produce vast amounts of algal biomass is the use of closed tubular photobioreactors (PBR). The heat requirement for a given system is a major concern since the best algae growth rates are obtained between 25-30 °C, depending on the specific strain. A procedure to determine temperature influence on algal growth rates was developed for a lab-scale PBR system using the species Chlorella. A maximum growth rate of 1.44 doublings per day at 29 °C (optimal temperature) was determined. In addition, a dynamic mathematical model was developed to simulate heating and cooling energy requirements of tubular PBRs for any desired location. Operating the model with hourly weather data as input, heating and cooling loads can be calculated early in the planning stage of a project. Furthermore, the model makes it possible to compare the operation inside a greenhouse to the outdoor operations, and consequently provides fundamental information for an economic feasibility study. The best configuration for a specific location can be evaluated easily. The model was exemplary tested for a hypothetical 100,000 l photobioreactor located in San Luis Obispo, California, U.S.A. Average algae productivity rates of 23% and 67% for outdoor and indoor PBR operations, respectively, were obtained. Actual energy loads (heating and cooling) needed to maintain the PBR at optimal temperature were determined and compared. Sensitivity analyses had been performed for abrupt temperature and solar radiation steps, PBR row distances, ground reflectivities, and ventilation rates of the greenhouse. An optimal row distance of 0.75 m was determined for the specific PBR. The least amount of energy was needed for a ground reflectivity of 20%. The ventilation rate had no major influence on the productivity rate of the system. Results demonstrated the importance of a simulation model as well as the economic impact of a sophisticated heat management system. Energy savings due to an optimized heat management system will eventually increase proficiency of the systems, which will support a new sustainable industry and future developmental potential.
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Vytápění bytového domu / Heating of flat houseZajíček, Václav January 2019 (has links)
The thesis is composed of three parts - theoretical, computational and a project part. The theoretical part deals with heat sharing through conduction, flow and radiation. The computational part is focused on the overall calculation of the heating system to operate smoothly and reliably. Three gas condensing boilers are designed as a source of heat. The heating of the water is solved as a reservoir. It's source of heat is one gas condensation boiler. The project part contains a technical report and the project documentation on the stage of the implementation dossier.
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