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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

Projeto, construção e avaliação experimental de um lavador de gases industrial. / Design, fabrication and experimental evaluation of a industrial cyclone washer.

Majewski, Ryszard 11 October 2006 (has links)
Ciclones são equipamentos largamente empregados na separação de partículas do ar ou na limpeza de gases de processos por ação da força centrífuga. Neste trabalho, um ciclone lavador modificado foi projetado, construído, e sua eficiência de coleta de partículas foi avaliada. O equipamento consiste de um ciclone separador tipo Americano com triplo cone, em cujo corpo cilíndrico foram introduzidos bicos nebulizadores de água. Graças a essa configuração ele pode ser usado em galpões industriais, apresenta facilidade de construção e operação e baixo custo. O autor projetou esse ciclone objetivando não somente a eficiência de coleta, mas também a compacidade, o baixo consumo de água e de eletricidade, a possibilidade de purificação de gases ou vapores tóxicos, e ainda, o resfriamento de gases quentes pela umidificação até a saturação, de acordo com os fundamentos da separação de poeiras empregada nos scrubbers úmidos. O estudo consistiu de uma avaliação experimental das condições de operação à temperaturas ambiente e superiores à ambiente, variando também a altura da chaminé e a vazão de água de umidificação da poeira. Os ensaios foram realizados em duas etapas. Na primeira, objetivou-se identificar as melhores condições de operação usando todo o potencial de variação do equipamento, e empregando um projeto fatorial de três fatores (three-way). A segunda etapa objetivou-se estimar a eficiência de coleta do ciclone lavador usando como poluente, partículas de quartzo micronizado com diâmetro médio de 7,48 µm. A concentração de partículas no gás foi de 20 a 100 mg/m3 de ar. Foi obtida uma eficiência média de 97.07±1.03 %, para 4 bicos nebulizadores, 4 aquecedores em funcionamento e altura da chaminé 645 mm, para uma vazão de gás 0,358 m3/s de gás. Concluindo a modificação do projeto aumento a eficiência de coleta de aproximadamente 70 % ,em ciclones secos, para 97,07 %. / Cyclones are devices widely employed to separate and collect particles from the air or for cleaning up gases for processes by the action of centrifugal force. In this work a modified cyclone washer was designed, fabricated, and its collection efficiency evaluated. This equipment consists of an Americantype cyclone separator with a triple cone into whose cylindrical body a spray nozzle was introduced. Thanks to its configuration, it can be used in industrial warehouses and is fairly simple to build and operate, as well as inexpensive. The author designed this cyclone with a view not only to efficiency but also compactness, low water and electricity consumption, the possibility of toxic gas or vapor absorption, the cooling of hot gases and aerosol humidification up to saturation, according to fundamentals of dust separation with wet scrubbers. The study consisted of an experimental evaluation of the operating conditions at ambient and higher than ambient temperatures, changing the chimney height and water flow rate, with the purpose of humidifying dust. The tests were carried out in two steps. The first step aimed to identify the best operating condition using the entire potential variation and employing a three-way factorial design. The second step aimed to estimate the efficiency of the cyclone washer was evaluated in the collection of micronized quartz particles with an average diameter of 7.48 µm. The amount of particles varied from 20 to 100 mg/m3 of air. An average efficiency of 97.07±1.03 % was obtained with four spray nozzles, with its four heaters turned on, chimney height of 0.645 m and 0.358 m3/s of gas. In conclusion, the design modification had increased the collection efficiency from about 70 %, in dry cyclones, to 97.07 %.
12

Projeto, construção e avaliação experimental de um lavador de gases industrial. / Design, fabrication and experimental evaluation of a industrial cyclone washer.

Ryszard Majewski 11 October 2006 (has links)
Ciclones são equipamentos largamente empregados na separação de partículas do ar ou na limpeza de gases de processos por ação da força centrífuga. Neste trabalho, um ciclone lavador modificado foi projetado, construído, e sua eficiência de coleta de partículas foi avaliada. O equipamento consiste de um ciclone separador tipo Americano com triplo cone, em cujo corpo cilíndrico foram introduzidos bicos nebulizadores de água. Graças a essa configuração ele pode ser usado em galpões industriais, apresenta facilidade de construção e operação e baixo custo. O autor projetou esse ciclone objetivando não somente a eficiência de coleta, mas também a compacidade, o baixo consumo de água e de eletricidade, a possibilidade de purificação de gases ou vapores tóxicos, e ainda, o resfriamento de gases quentes pela umidificação até a saturação, de acordo com os fundamentos da separação de poeiras empregada nos scrubbers úmidos. O estudo consistiu de uma avaliação experimental das condições de operação à temperaturas ambiente e superiores à ambiente, variando também a altura da chaminé e a vazão de água de umidificação da poeira. Os ensaios foram realizados em duas etapas. Na primeira, objetivou-se identificar as melhores condições de operação usando todo o potencial de variação do equipamento, e empregando um projeto fatorial de três fatores (three-way). A segunda etapa objetivou-se estimar a eficiência de coleta do ciclone lavador usando como poluente, partículas de quartzo micronizado com diâmetro médio de 7,48 µm. A concentração de partículas no gás foi de 20 a 100 mg/m3 de ar. Foi obtida uma eficiência média de 97.07±1.03 %, para 4 bicos nebulizadores, 4 aquecedores em funcionamento e altura da chaminé 645 mm, para uma vazão de gás 0,358 m3/s de gás. Concluindo a modificação do projeto aumento a eficiência de coleta de aproximadamente 70 % ,em ciclones secos, para 97,07 %. / Cyclones are devices widely employed to separate and collect particles from the air or for cleaning up gases for processes by the action of centrifugal force. In this work a modified cyclone washer was designed, fabricated, and its collection efficiency evaluated. This equipment consists of an Americantype cyclone separator with a triple cone into whose cylindrical body a spray nozzle was introduced. Thanks to its configuration, it can be used in industrial warehouses and is fairly simple to build and operate, as well as inexpensive. The author designed this cyclone with a view not only to efficiency but also compactness, low water and electricity consumption, the possibility of toxic gas or vapor absorption, the cooling of hot gases and aerosol humidification up to saturation, according to fundamentals of dust separation with wet scrubbers. The study consisted of an experimental evaluation of the operating conditions at ambient and higher than ambient temperatures, changing the chimney height and water flow rate, with the purpose of humidifying dust. The tests were carried out in two steps. The first step aimed to identify the best operating condition using the entire potential variation and employing a three-way factorial design. The second step aimed to estimate the efficiency of the cyclone washer was evaluated in the collection of micronized quartz particles with an average diameter of 7.48 µm. The amount of particles varied from 20 to 100 mg/m3 of air. An average efficiency of 97.07±1.03 % was obtained with four spray nozzles, with its four heaters turned on, chimney height of 0.645 m and 0.358 m3/s of gas. In conclusion, the design modification had increased the collection efficiency from about 70 %, in dry cyclones, to 97.07 %.
13

Desenvolvimento de misturas tern?rias para remo??o de reboco de fluido de perfura??o sint?tico

Pinheiro, Francisca Sheldakelle Holanda Torres 01 April 2013 (has links)
Made available in DSpace on 2014-12-17T15:42:26Z (GMT). No. of bitstreams: 1 FranciscaSHTP_TESE.pdf: 2918129 bytes, checksum: e712b711537d456c1dd4eaa0f003f3af (MD5) Previous issue date: 2013-04-01 / The construction of wells is one of the most important activities of the oil industry. The drilling process is the set of activities and operations to design, program and perform the opening thereof. During this process, the cuttings are removed by the drilling fluid, or mud, and carted to the surface. This fluid is injected into the drill string and returns to the surface through the annular space between the well walls and the drill string. After the descent of the column casing, the annular space between the casing string and the walls of the borehole is filled with cement so as to secure the spine and prevent any migration of fluids between the various permeable zones traversed by the well behind of the coating. To ensure the good quality of the cementation scrubbers are used mattresses which are pumped ahead of the cement slurry so as to avoid contamination of the drilling fluid paste, or vice versa, and assist in the removal of plaster, formed by drilling fluid of the borehole walls, thus enabling a better cement bond to the well. Within this context, this work aims to evaluate the efficiency of mattresses scrubbers, the basis of ionic and nonionic surfactants, on the removal of nonaqueous drilling fluid, based on n-paraffin in oil wells, and the compatibility between the Mattress relations washer / drilling fluid bed scrubber / cement paste mattress washer / cement slurry / drilling fluid and the drilling fluid / cement slurry using laboratory tests rheology, thickening time and compressive strength. Also technique was performed X-ray diffraction (XRD) for a more detailed analysis of these mixtures with hydrated cement paste. In compatibility tests the conditions of temperature and pressure used in the same laboratory procedure simulating the conditions of oil wells, the well is considered the depth of 800 m. The results showed that the compositions of the mattress washer nonionic, KMS obtained a 100% efficient in removing the non-aqueous drilling fluid, and the best formulation showed good results with respect to compliance testing / A constru??o de po?os ? uma das atividades mais importantes da ind?stria do petr?leo. O processo de perfura??o de po?os ? o conjunto de atividades e opera??es destinadas a projetar, programar e realizar a abertura dos mesmos. Durante este processo, os cascalhos s?o removidos pelo fluido de perfura??o, ou lama, e carreados at? a superf?cie. Este fluido ? injetado no interior da coluna de perfura??o e retorna ? superf?cie atrav?s do espa?o anular entre as paredes do po?o e a coluna de perfura??o. Ap?s a descida da coluna de revestimento, o espa?o anular entre a coluna de revestimento e as paredes do po?o ? preenchido com cimento, de modo a fixar a coluna e evitar que haja migra??o de fluidos entre as diversas zonas perme?veis atravessadas pelo po?o, por tr?s do revestimento. Para garantir a boa qualidade da cimenta??o, s?o utilizados os colch?es lavadores, que s?o bombeados ? frente da pasta de cimento, de modo a evitar a contamina??o da pasta pelo fluido de perfura??o, ou vice-versa, al?m de auxiliar na remo??o do reboco, formado pelo fluido de perfura??o, das paredes do po?o, possibilitando assim uma melhor ader?ncia do cimento ao po?o. Dentro deste contexto, este trabalho tem como objetivo avaliar a efici?ncia de colch?es lavadores, a base de tensoativos i?nico e n?o i?nico, na remo??o do fluido de perfura??o n?o aquoso, ? base de n-parafina, em po?os de petr?leo, e a compatibilidade entre as rela??es colch?o lavador/fluido de perfura??o, colch?o lavador /pasta de cimento, colch?o lavador /pasta de cimento/fluido de perfura??o e fluido de perfura??o/pasta de cimento utilizando os ensaios laboratoriais de reologia, tempo de espessamento e resist?ncia ? compress?o. Tamb?m foi realizada a t?cnica difra??o de raios X (DRX) para uma an?lise mais detalhada dessas misturas com a pasta hidratada de cimento. Nos ensaios de compatibilidade as condi??es de temperatura e press?o utilizadas nos procedimentos laboratoriais simularam as mesmas condi??es dos po?os de petr?leo, sendo a profundidade do po?o considerada de 800 m. Os resultados mostraram que as composi??es do colch?o lavador n?o i?nico, o KMS, obtiveram uma efici?ncia de 100% na remo??o do fluido de perfura??o n?o aquoso e a sua melhor formula??o apresentou resultados satisfat?rios em rela??o aos testes de compatibilidade
14

Avaliação do ciclo de vida: principais métodos e estudo comparativo entre o cesto de plástico e de inox de uma lavadora de roupa / Life cycle assessment: main methods and comparative study between the plastic and stainless steel of the washer machine\'s basket

Anderson Ricardo Bortolin 28 May 2009 (has links)
Os produtos podem causar impactos negativos ao meio ambiente em uma das suas etapas do ciclo de vida, quais sejam: aquisição de matéria-prima, fabricação, distribuição, uso e disposição final. A integração dos aspectos ambientais no projeto e no desenvolvimento de produto busca prevenir e minimizar os possíveis impactos ao longo de seu ciclo de vida. Esses impactos variam quanto à categoria, magnitude, extensão e duração. A principal metodologia para avaliar os impactos ambientais do ciclo de vida do produto é a Avaliação do Ciclo de Vida (ACV). Contudo há diversos métodos e formas de aplicações desta metodologia. O primeiro objetivo é identificar os principais métodos da ACV, por meio de uma revisão sistemática, O segundo é realizar um estudo de caso comparativo da ACV entre dois tipos de cestos (de plástico e de aço inox) utilizados nas lavadoras de roupas automáticas, identificando os potenciais impactos ambientais, baseado no método EDIP. Os principais métodos identificados na revisão sistemática foram: Ecoindicator 99, EPS, CML Ecological Footprint e EDIP. A comparação do ciclo de vida dos dois cestos demonstra que, para as categorias de impactos de potencial de aquecimento global, acidificação, eutrofização, ecotoxidade e toxidade humana, o cesto inox tem uma maior contribuição para os potencias impactos ambientais em relação ao cesto de plástico, principalmente devido à maior distância transportada da matéria-prima do aço até a fabricação do cesto. / The products can cause negative impacts to the environment in one of their stages of the life cycle, which are: raw material acquisition, production, distribution, use and final disposition. The integration of the environmental aspects in the project and in the product development it looks for to prevent and to minimize the possible impacts along his life cycle. Those impacts vary as for the category, magnitude, extension and duration. The main methodology to evaluate the environmental impacts of the life cycle of the product is the Life Cycle Assessment (LCA). However there are several methods and forms of applications of this methodology. The first objective is to identify the main methods of LCA, through a systematic revision, THE second is to accomplish a study of comparative case of LCA among two types of baskets (of plastic and of stainless steel) used in the washers of automatic clothes, identifying the potentials environmental impacts, based on the method EDIP. The main identified methods in the systematic revision were: Echo-indicator 99, EPS, CML Ecological Footprint and EDIP. The comparison of the cycle of life of the two baskets demonstrates that, for the categories of impacts of potential of global warming, acidification, nutrient enrichment, ecotoxicity and human toxicity, the basket stainless steel has a larger contribution for the potencies environmental impacts in relation to the basket of plastic, mainly due to the largest transported distance of the raw material of the steel to the production of the basket.
15

Srovnání MKP modelů spojů / Comparision of FEM models of joints

Hlaváč, Martin January 2011 (has links)
This thesis deals with the comparison of alternative models of the simplified joints used in the FEM models of complex models with detailed joint details. This is essentially a screw connection with dowel bolt and standard bolt, weld connection "T" and overlap weld connection. Individual connections are compared in the simulation results of matching models.
16

De-icing and ice prevention of automotive headlamps and tail lamps : - An investigation of techniques and development of a test method / Avisning och isförebyggande åtgärder för huvudstrålkastare och baklyktor : - En undersökning av tekniker och utveckling av en testmetod

Jansson, Anders January 2014 (has links)
The work aims to study different methods suitable for de-icing and ice prevention of vehicle headlamps and tail lamps, especially LED-lights. Furthermore, the work aims to investigate the scale of the problem with insufficient or lack of de-icing on automotive lamps depending on the region and the environment the vehicle operates in. The problem with insufficient de-icing in automotive lamps was investigated by observations, tests of various lamps and a driver survey. Deicing methods were identified through a litera-ture review. The methods were studied in detail, and some were also evaluated by tests. The tests were narrowed down to temperature measurements and de-icing measurements. The latter were performed using a test method especially developed for the task. The collected data was used to evaluate whether actions are needed to be taken and to form recommen-dations for future developments. The number one priority should be to improve the tail lamps de-icing ability. Headlamps can also be improved but there is no imminent need. Insufficient de-icing of headlamps and tail lamps can potentially be a problem in all areas subjected to cold winter climate. Tail lamps should be fitted with electrical heating in order to improve the de-icing ability. They should be positioned so that snow and ice does not stack on top of them. The de-icing time of tail lamps should be less than 10 min. Truck drivers needs to be better in scraping their headlamps and tail lamps. The time needed for de-icing Scania’s H7 headlamps is 20 min for halogen version and 35 min for xenon version at -18 °C. This should be compared to the BMW LED-headlamp which needs 65 min to complete de-icing. LED-headlamps are probably limited to a de-icing time of approximately 60 min unless additional heat is added to the headlamp lens. The fastest and most efficient way to de-ice the headlamps is to use hot washer fluid. Electrically heated lenses are also effective but the de-icing process is slower. The proposed test method is a simple and effective way to compare and evaluate headlamps and tail lamps without knowing internal airflows and light sources. The way the ice layer is created on the device under test is unique to this method. The created ice layer is extremely uniform and the results are easy to evaluate. / Sammanfattning Arbetets syfte är att undersöka olika avisningsmetoder och isförebyggande åtgärder för hu-vudstrålkastare och baklyktor, speciellt LED-lampor. Ytterligare syfte är att undersöka hur stort problemet med otillräcklig avisning är beroende på vilken region och miljö som fordonen körs i. Problemet med otillräcklig avisning av fordonsbelysning har undersökts genom observatio-ner, en förarenkät samt genom tester av olika strålkastare och baklyktor. Avisningsmetoder har identifierats genom en litteraturstudie. Metoderna har studerats i detalj och några har även utvärderats genom tester. Testerna har utförts enligt en för uppgiften framtagen testme-tod. De insamlade uppgifterna har sedan används för att utvärdera om åtgärder behöver vid-tas och för att ge rekommendationer för framtida utvecklingsprojekt. Första prioritet bör vara att förbättra baklyktornas avisningsförmåga. Huvudstrålkastarna kan även de förbättras men det föreligger inte i dagsläget något akut behov av det. Otillräcklig avisning av huvudstrålkastare och bakljus kan potentiellt vara ett problem i alla miljöer med ett kallt vinterklimat. Baklyktorna bör utrustas med en eluppvärmd lins för att förbättra avis-ningen. Lamporna bör placeras på ett sådant sätt att snö och is inte kan ansamlas ovanpå dem. Avisningstiden för en baklykta bör inte överstiga 10 min. Lastbilschaufförerna behöver bli bättre på skrapa av is och snö från huvudstrålkastare och baklyktor. Avisningstiden för Scanias H7 huvudstrålkastare är 20 min för halogen versionen och 35 min för xenon versionen vid -18 °C. Detta kan jämföras med att BMW:s LED-huvudstrålkastare behöver 65 min för att avisas. LED-huvudstrålkastare är troligtvis begränsade till en avis-ningstid kring 60 min om inte någon extra värme tillförs. Den snabbaste metoden för att avisa en huvudstrålkastare är att använda varm spolarvätska men elektrotermisk avisning kan också vara mycket effektivt. Den föreslagna testmetoden är ett enkelt sätt att jämföra och utvärdera olika huvudstrålkastare och baklyktor. Det som är unikt med testmetoden är hur isskiktet på lamporna bildas. Isskiktet som skapas är extremt jämt och lätt att utvärdera.
17

Kan automation på sterilcentralen förbättra arbetsmiljön på Nya Karolinska sjukhuset? / Could Automation at the Central Sterile Department Improve the Work Environment at the New Karolinska Hospital?

Dahlström, Jesper, Lundström, Alexander January 2022 (has links)
Sterilcentralen som finns på nya Karolinska Universitetssjukhuset är inte modern. Den är dessutom inte tillfredsställande ur ett arbetsmiljömässigt perspektiv.  Det finns redan ett antal beprövade automationsmetoder som är implementerade på olika sjukhus, men inte på NKS. Det finns ett antal olika processer som ett material måste genomgå för att det ska bli sterilt. De flesta sköts manuellt. Kan automation förverkligas för att minska mängden manuellt arbete samt förbättra arbetsmiljön för avdelningens personal? Ett frågeformulär användes för att ta reda på hur personalen som arbetar på avdelningen uppfattar arbetet som utförs. Formuläret var också till för att ta reda på hur de tror att arbetet och arbetsmiljön kan förbättras genom automation. Fältstudier samt besök på andra sjukhus gjordes för att undersöka hur arbetet på sterilcentralen går till i praktiken. / The central sterile department that is located at the new Karolinska Hospital is not up to date. It is not satisfying from a work environmental perspective. There are however a number of proven methods of automation that are implemented at different hospitals but not at NKS. There are a number of different processes that have to be executed on an instrument to be able to classify it as sterile. Most of the work is done manually. Could automation be implemented to reduce the number of work done manually and to improve the work environment for the employees of the department? A questionnaire was used to figure out how the staff that works at the department perceives the work that is being done. The questionnaire was also used to figure out the staff's point of view on how the work processes and work environment can be improved due to automation. Field studies and visiting other hospitals were executed to study how the work at the central sterile department is done in reality.

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