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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.
1

An experimental investigation of the dynamic behaviour of an externally pressurized thrust bearing

Alabraba, M. January 1985 (has links)
No description available.
2

Experimental and theoretical determination of connecting rod big-end bearing journal motion

Groves, Christopher John January 2000 (has links)
No description available.
3

Jämförelsestudie avseende stomsystem : Ramverk eller fackverk/balk/pelar-system / Comparative study on load bearing system : Framework or column and truss/beam system

Lindberg, Johan January 2013 (has links)
Projektet omfattade en jämförelsestudie avseende stomsystem. Studien undersökte ramverk och fackverk/balk/pelar-system och genomfördes självständigt med stöttning av Ramböll AB´s kontor i Falun. Syftet var främst att undersöka vilka skillnader det finns mellan tvåledsramar och fackverk/balk/pelar-system för lätta hallbyggnader och försöka få klarhet i varför fackverk/balk/pelar-system är det dominerande systemet i Sverige eftersom övriga Europa har tagit en annan utveckling och domineras av tvåledsramar. Studien undersöker skillnaderna mellan systemen i en hallbyggnad med förutbestämda mått i stål.Inledningsvis gjordes en litteraturstudie för att få en bredare bakgrund av systemen och en bättre förståelse om förutsättningarna för varje system. Efter litteraturstudien kunde sedan ett typhus och beräkningsunderlag för jämförelsestudien tas fram. Även en enkätstudie gjordes med syftet att skapa en tydlig bild av vilket stomsystem konstruktörer i Sverige oftast väljer och varför. Resultatet av studien visade att tvåledsramar ger en ökad kostnad jämfört med fackverk/balk/pelar-system i materialåtgång och framställning samt att beräkningarna blir mer komplicerade. Skulle fortsatta studier göras med dessa system i byggnader med andra mått skulle det kanske gå att få fram speciella mått på byggnader där kostnaden för tvåledsramar blir densamma som för fackverk/balk/pelar-system och därför är ett likvärdigt alternativ som stomsystem.En viktig slutsats från projektet är att tvåledsramar används mycket mer sällan än fackverk/balk/pelar-system som stomsystem i lätta hallbyggnader i Sverige på grund av att kostnaderna blir mycket högre med tvåledsramar och att det är ett mer komplicerat system i beräkningsarbetet. De viktigaste slutsatserna från jämförelsestudien går att sammafatta som följande: Tvåledsramar är dyrare att använda. Tvåledsramar är ett mer komplicerat system beräkningsmässigt. Traditionen av att använda tvåledsramar finns inte och därför används inte systemet. / The project included a comparison study on frame systems. The study investigated framework and truss/beam/column-system and was conducted independently with support of Ramboll AB 's office in Falun. The aim was primarily to examine what differences there are between frameworks with two joints and truss/beam/column-systems for light industrial buildings and try to determine why the truss/beam/column-system is the dominant system in Sweden because the rest of Europe has taken a different development and dominated by framework with two joints. The study examines the differences between the systems in a industrial building with predetermined dimensions in steel.Initially, a literature study was conducted to gain a broader view of the systems and to create a better understanding for the conditions for each system. After the literature study was conducted could a exampelhouse and underlay for the comparison study be developed. A survey study were also conducted and the purpose was to create a clear picture of which system the frame system designers in Sweden usually choose and why. The results of the study showed that frameworks with two joints give an increased cost compared with truss/beam/column-system in material consumption and production, and the calculations become more complicated for the framwork. Should further studies be done with these systems in buildings with other measurements, it might possible to obtain specific measures of buildings where the cost of frameworks with two joints will be the same as for a building with truss/beam/column-system and therefore become an equivalent alternative.An important conclusion of this project is that a framework with two joints is used much more rarely than truss/beam/column-system as frame systems in light industrial buildings in Sweden because the cost will be much higher with a framework with two joints and that it is a more complicated system in the computational work . The main conclusions from comparative study can be summarized as follows: Framwork with two joints is more expensive to use. Framework with two joints is a more complicated system computationally. The tradition of using framework with two joints does not exist and it's therefore the system does not being used.
4

Dynamic Analysis Of A Rotor Bearing System

ElHibir, Sandi 29 June 2009 (has links)
No description available.
5

Projeto, construção e testes de desempenho "In Vitro" de uma bomba de sangue centrifuga implantavel / Design, manufacture and performance tests "In Vitro" of an implantable centrifugal blood pum

Bock, Eduardo Guy Perpétuo 02 May 2007 (has links)
Orientadores: Antonio Celso Fonseca de Arruda, Aron Jose Pazin de Andrade / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-09T06:51:30Z (GMT). No. of bitstreams: 1 Bock_EduardoGuyPerpetuo_M.pdf: 3873649 bytes, checksum: 91eb2ac5543b164e576ca7a5e61d6a45 (MD5) Previous issue date: 2007 / Resumo: Uma bomba centrífuga implantável foi projetada e construída para assistência ventricular de longa duração no tratamento de pacientes portadores de doenças cardiovasculares. A metodologia utilizada foi a de testes de desempenho ¿in vitro¿ compostos de testes de atrito para seleção de materiais para os mancais de apoio, testes de desempenho hidrodinâmico da bomba e testes com sangue humano para a verificação da hemólise causada no bombeamento. Os primeiros testes foram realizados com uma bomba centrífuga não implantável, normalmente utilizada em cirurgias cardíacas, para a determinação do posicionamento do orifício de entrada da bomba. Foram realizadas simulações numéricas por computador para dimensionamento da bomba. Testes de atrito foram feitos para a seleção de materiais do sistema de mancais de apoio proposto para alcançar a durabilidade necessária. Testes de desempenho hidrodinâmico foram utilizados para determinar o melhor desenho para o rotor da bomba. Seu desempenho foi comparado com uma bomba não implantável e com uma bomba implantável similar americana e apresentou melhores resultados que ambas. Testes com sangue foram feitos para quantificar os danos causados aos componentes do sangue pela bomba. O seu índice normalizado de hemólise foi de 0,0054 mg/100L, considerado excelente por se encontrar próximo do limite mínimo encontrado na literatura: entre 0,004 g/ 100L e 0,02 g/ 100L. Como trabalhos futuros, serão feito testes com animais para que a bomba centrífuga implantável possa ser utilizada em pacientes / Abstract: An implantable centrifugal blood pump was developed for long-term ventricular assistance in cardiac patients. In vitro tests were performed, as wear evaluation, performance tests and hemolysis tests in human blood. Preliminary tests were performed with a non-implantable pump in order to properly locate the inlet port. Numerical computational simulations were performed in order to predict its best geometry. Wear evaluations helped to select the best materials for double pivot bearing system proposed to achieve longer durability. Performance tests pointed the best impeller geometry. The implantable centrifugal blood pump was compared with other two blood pumps. One is a centrifugal blood pump for cardiopulmonary bypass and the other is a similar implantable device. The proposed implantable centrifugal blood pump showed the best performance. But, its results showed a strong descendant curve in high flow. Other prototype was manufactured with a different inlet port angle to overcome this problem. The normalized index of hemolysis (NIH) tests was performed with human blood pumped in an In Vitro closed circuit (mock loop) in normalized conditions, as flow of 5 L/min and total pressure ahead of 100 mm Hg. After six hours, NIH measured 0.0054 mg/100L that can be considered excellent since it is close to the minimum found in literature (between 0.004 g/ 100L e 0.02 g/ 100L). As future work, in vivo test will be performed with the implantable centrifugal blood pump looking forward to implant it in patients / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica
6

Controle de um sistema dinâmico rotativo utilizando mancais com atuadores LMF

Borges, Jader Morais 29 January 2016 (has links)
Submitted by Maike Costa (maiksebas@gmail.com) on 2017-06-05T13:40:29Z No. of bitstreams: 1 arquivototal.pdf: 5062577 bytes, checksum: 50662b1886cf46d934e60415729f24cd (MD5) / Made available in DSpace on 2017-06-05T13:40:29Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 5062577 bytes, checksum: 50662b1886cf46d934e60415729f24cd (MD5) Previous issue date: 2016-01-29 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Most rotating machines, especially those mounted on flexible shafts and bearings when it’s accelerating, tend to pass through critical speeds, which are speeds that can cause structural resonance in the system. Thus, there is a constant concern for seeking effective methods to reduce the effect of vibration when passing through such speeds. Currently there are many applications of "smart materials" as actuators in dynamical systems, in order to reduce vibrations in a frequency range next to the resonance zone. In this direction the use of actuators composed by shape memory alloys (SMA) assists in active control structures, due the capacity of stiffness variation with change of the temperature. This thesis presents a shaft-rotor system design with active bearing, using SMA springs and temperature control system based on fuzzy logic, to reduce the vibration amplitudes when passing through critical speeds. This reduction occurred from the system stiffness change (active support bearing), obtained by changing the temperature of the SMA springs. The theoretical and experimental results showed the system functionality, being achieved reductions of up to 61.5% in the peak amplitudes and 57.3% in terms of RMS signal during the passage through resonance zone. / A maioria das máquinas rotativas, sobretudo aquelas montadas sobre eixos e mancais flexíveis, quando de seu início de funcionamento, tendem a passar por velocidades ditas críticas, ou seja, velocidades que podem levar o sistema a entrar em ressonância estrutural. Assim, existe uma preocupação constante pela busca de métodos eficazes de atenuar o efeito da vibração quando da passagem por tais velocidades. Atualmente vêm-se estudando aplicações de “materiais inteligentes” como atuadores em sistemas dinâmicos, com o propósito de reduzir as vibrações numa faixa de frequência relacionada à região de ressonância. Nesta direção está o uso de atuadores compostos por ligas com memória de forma (LMF), que auxiliam no controle ativo de estruturas, devido à sua capacidade de variação de rigidez em função da mudança de temperatura. Apresenta-se, nesta tese, uma concepção de sistema eixo-rotor com mancal ativo, fazendo uso de molas LMF e sistema de controle de temperatura baseado na lógica fuzzy, visando reduzir as amplitudes de vibração quando da passagem por velocidades críticas. Tal redução ocorreu a partir da mudança de rigidez do sistema (mancal de suporte ativo), obtido pela mudança da temperatura das molas. Os resultados teóricos e experimentais do funcionamento do sistema mostraram a sua funcionalidade, sendo obtidas reduções de até 61,5% nas amplitudes de pico e de 57,3% em termos de RMS do sinal, durante a passagem pelas regiões de ressonância.
7

Výstavní pavilon / Exhibition Pavilion

Očadlík, Martin January 2017 (has links)
The aim of the final thesis was to design and check the steel loadbearing structure of the exhibition pavilon. The basis for the structural design was a specified building layout. The assessment of the structure was made according to valid czech and european standards, including the system of "Eurocodes". Construction is situated in Zlin. The rectangular plan of the building is 45,0 m wide and 48,0 m long. The peripheral field of the roof is flat, while the central field is designed as a barrel roof. Main truss was designed with 6,0 m centre to centre distance. Structural design of the main loadbearing elements was made by the Dlubal RFEM v.5.07 software. Selected structure elements, including joints and column anchors were verified manualy.
8

Administrativní budova / Office building

Výborný, Vojtěch January 2022 (has links)
This master´s project deals with design of an office building nearly zero energy standard. My master´s project consists of three parts. In the first one I work on technical design of the office building. It is a three-storey building with partial basement. Vertical load-bearing system is partially made from monolithic concrete walls and partially from clay blocks walls. The horizontal load-bearing structures are made of monolithic concrete slab. All roofs are designed as flat roofs. In second part I design all technical equipment in this building. In the last part I compare three types of roof, photovoltaic power plants and evaluate their environmental impact. First type of PV power plant is made by monocrystalline solar cell, second one by polycrystalline solar cell and last one by monocrystalline solar cell with battery system. Environmental impact of these systems is evaluated in Open LCA software. All structures comply with the valid standards and regulations.
9

Polyfunkční dům / Multifunctional building

Mikudík, Patrik January 2022 (has links)
The subject of the diploma thesis is to elaborate the project documentation of a newbuilt multifunctional building in Považská Bystrica. The multifunkcional building is designed as a three-storey without basemen. In the first ground floor there are dental and gynecological surgeries with facilites, a cafe and director's office. In the second there are office spaces with facilities for rent. On the level of the third floor there are two-rooms flats and one four-room flat, while there are also storage spaces for each of the flats. The building of the multifunctional house is based on reinforced concrete foundations. The vertical construction system consist of reinforced concrete perimeter walls and perimeter reinforced concrete columns in combination with an internal load-bearing walls of the reinforcing core of the building. The partition walls are designed as a plasterboard walls. The horizontal load-bearing structures are made of reinforced concrete prestressed panels. The roofing of the building is designed as a flat one-layer roof. The roof of the terrace consist of an extensive vegetation flat one-layer roof. The roofing of the awning at the main entrance to the building is design as a reinforced concrete monolithic console with one-layer flat roof a skylight. The building is insulated with the external thermal insulation composite system (ETICS). The façade of the communication core of the building is made of brick cladding. The rest of the façade is made of a thin layer white plaster.
10

Stavebně technologický projekt hotelu Nábřeží u Kunovské přehrady / Construction-technological project of the Hotel Nábřeží near Kunov dam

Vavřínek, Dominik Unknown Date (has links)
This diploma thesis deals with construction and technological solution of hotel Nábřeží near Kunovská dam. The aim of this work is to choose the appropriate construction process of rough construction. Thesis contains technical report of main object, technological prescription and test plan for reinforced concrete ceiling, work plan and schedule of work also project of site equipment, main construction machinery and noise measurement survey. Further there is financial and time demand comparison of existing and alternative design of vertical load-bearing system in the connection with thermal insulation.

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