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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.
191

Soldagem FHPP - processo e metalurgia nas transformações das fases de um aço C-Mn

Lessa, Cleber Rodrigo de Lima January 2011 (has links)
Este trabalho teve como objetivo observar o resultado da variação dos parâmetros do processo FHPP (Friction Hydro Pillar Processing), dando-se atenção aos efeitos destes na microestrutura e na qualidade do reparo. O estudo foi realizado através de investigações metalográficas nos reparos obtidos, bem como análises via perfis de microdureza Vickers. Foram utilizadas diferentes forças axiais, que levaram a obtenção de reparos isentos de defeitos no seu preenchimento. Observou-se que o utilizando forças axiais maiores contribuíram para obter microestrutura mais refinada e homogênea, com formação predominante de martensita, menor tempo de processamento, menor quantidade de constituinte Martensita-Austenita e uma Zona Termicamente Afetada (ZTA) de menor tamanho. / This study aimed to observe the result of the variation of the Friction Hydro Pillar Processing parameters, giving attention to the microestructural effects and quality of repair. The study was carried out by metallographic investigations in repairs obtained and Vickers microhardness profiles. Were used different axial forces, which led to obtain no defects in repairs. It was observed that using higher axial forces helped to get more refined and homogeneous microstructure with predominant formation of martensite, lower processing time, less amount of Martensite-Austenite constituent and lower Heat Afecfted Zone (HAZ) size.
192

Simetria axial : uma seqüência didática para alunos da 6ª série com o uso de software de geometria dinâmica

Socorro Alves, Dayse January 2005 (has links)
Made available in DSpace on 2014-06-12T17:22:21Z (GMT). No. of bitstreams: 2 arquivo5751_1.pdf: 3149146 bytes, checksum: 57a28c5fc903c6caa60e16df268f8cd2 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2005 / Inserindo-se no âmbito do ensino e aprendizagem da Geometria, esta pesquisa propõe a investigação dos efeitos de uma seqüência didática sobre o conceito de um tipo de Isometria, a Reflexão Axial, com treze alunos da 6ª série de uma escola pública, em um ambiente de geometria dinâmica, o Cabri-Géomètre. Para isto, fundamentamo-nos nos preceitos teóricos de Hershkowith e Laborde no que diz respeito à visualização em Geometria e ao uso do Cabri-Géomètre de Hölzl sobre o arrastamento de figuras no Cabri e Artigue acerca da importância da seqüência didática como prática de pesquisa. Com este objetivo, procuramos, primeiramente, identificar os enfoques dos livros didáticos de 5ª a 8ª série, dos currículos americanos e franceses, do PCN de Matemática e posteriormente as concepções prévias dos alunos acerca do conceito, levando em conta as variáveis didáticas como eixo de reflexão, posição da figura, papel de base e propriedades da Reflexão Axial. Os resultados da seqüência apontaram a influência do Cabri-Géomètre no desempenho dos alunos quanto à construção de figuras simétricas assim como à associação entre os desenhos geométricos da tela e no que concerne às propriedades da Reflexão Axial. A seqüência didática foi eficiente quanto à identificação das características de pontos e figuras simétricas obtidos através da reflexão em torno de uma reta, do eixo de simetria, todavia, precisa ser retomada quanto às questões que visam à generalização das propriedades da Simetria Axial pelos alunos
193

Analise do comportamento de estaca pre-moldada de pequeno diametro, instrumentada, em solo residual de diabasio da região de Campinas

Albuquerque, Paulo José Rocha de, 1964- 23 October 1996 (has links)
Orientador: David de Carvalho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-07-22T14:43:06Z (GMT). No. of bitstreams: 1 Albuquerque_PauloJoseRochade_M.pdf: 5114225 bytes, checksum: f323024db4d31655f06e40776434085a (MD5) Previous issue date: 1996 / Resumo: Apresenta-se neste trabalho a análise de comportamento de uma estaca pré-moldada de 14m de comprimento e 0,18m de diâmetro, instrumentada, submetida à prova de carga dinâmica, à medida de repique elástico através do Sistema Repicômetro e a duas provas de carga estáticas em um intervalo de 44 dias. Sua instrumentação constituiu-se de extensômetros elétricos colados à barras de aço, instaladas em quatro níveis ao longo do fuste da estaca . Através da realização das provas de carga estática obteve-se os valores de carga última, recalques, atrito lateral e resistência de ponta. Comparou-se estes resultados aos obtidos na prova de carga dinâmica e do Sistema Repicômetro, e também aos calculados através dos métodos teóricos, empíricos e semi-empíricosde previsão de carga última e aos de previsão de recalques. Além destes parâmetros analisados, verificou-se o valor da carga residual após as duas provas de carga estáticas e sua variação ao longo do tempo / Abstract: It is presented the analysis of a instrumented driven pile behavior measuring 14m length by 0,18m of diameter, submitted to dynamie load test, elastie rebound measurement through "Repieômetro" Sistem, and two statie eompression load tests with an interval of 44 days. The instrumentation eonsisted of eleetrieal strain gages stieked to steel bars, installed in four levels alongside the pile shaft. The results obtained ITomstatie load tests were: ultimate loads, settlements, shaft metion and tip resistanee. These results were eompared with the obtained in dynamie load test and "Repieômetro" Sistem, and also ITom ealeulated theories, empiries and semiempiriesmethods of ultimate load and settlements prevision. Beyond these parameters, was verified the value of residualload after two statie load tests and it's variation along the time / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Agrícola
194

Armadura reduzida de cisalhamento em vigas de concreto de alta resistencia submetidas a flexo-compressão

Marinho, Adriano 08 October 1999 (has links)
Orientador: Armando Lopes Moreno Jr / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil / Made available in DSpace on 2018-07-26T15:21:20Z (GMT). No. of bitstreams: 1 Marinho_Adriano_M.pdf: 6352546 bytes, checksum: 7d1e398c1d8e8f55730c6c0e3ead22a5 (MD5) Previous issue date: 1999 / Resumo: Neste trabalho apresentam-se os resultados de uma investigação experimental sobre o comportamento ao cisalhamentode vigas de concreto de alta resistência submetidas à flexo-compressão, um total de três vigas, com resistência à compressão do concreto em tomo de 85 N/mm2foram analisadas. Todas as vigas tinham geometria e armaduras, longitudinal e transversal, idênticas.A única variável foi a intensidade da força normal de compressão aplicada a 25 cm da face superior das vigas. Os resultados obtidos nos ensaios, permitiram analisar o comportamento ao cisalhamento de cada viga, pode-se constatar que os critérios atuais de dimensionamento ao esforço cortante de vigas de concreto flexo-comprimidas,de acordo com NBR 61188 e a proposta de revisão desta, ACI 318-863e o CEB-FIPI99013apresentaram grande margem de segurança para as vigas flexo-comprimidas desta pesquisa. Com base nos resultados desta pesquisa, uma nova proposta para o dimensionamento ao esforço cortante de vigas submetidas à flexo compressão é apresentada ao final deste trabalho, obtendo resultados satisfatórios...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: This work presents a theoretical summary about shear in beams with normal and high-strength concrete and also the results of experimental investigation, conducted with high-strength concrete beams with axial compression force. Tests results permitted to analyzethe behavior of every beam, compare it with those made of normal-strength concrete and to verify if the shear design provisions of most current concrete design codes, could be extended to high-strength concrete beams with axial compression force...Note: The complete abstract is available with the full electronic digital thesis or dissertations / Mestrado / Estruturas / Mestre em Engenharia Civil
195

International Delphi study to assess the need for multiaxial criteria in diagnosis and management of functional gastrointestinal disorders

Austin, Philip Daniel January 2015 (has links)
Purpose: While there are diagnostic criteria for functional gastrointestinal disorders (FGIDs), their evaluation is challenging. This is because criteria are based on symptoms, and the underlying pathophysiology is not clear; as such, there are no gold standard tests. Diagnosis is further challenged by considerable clinical overlap between different FGIDs as well as other organic diseases, while many people with FGIDs have more anxiety and depression than healthy individuals. I hypothesised that assessment of separate components of FGIDs that also indicate their effect on the patient could improve diagnosis. My aim was to investigate the evolution of opinions from experts involved in the development of FGID diagnostic criteria on the proposal for the development of multiaxial assessment criteria (MAC) for FGIDs. Methods: I conducted a web-based Delphi study using a group of purposively sampled experts identified from committees of the Rome Foundation and the International Foundation for Gastrointestinal Disorders. From a systematic search of relevant articles, I generated132 items that were sent to experts as a first round survey. The items assessed risk and contributing factors, the therapeutic relationship, areas of evaluation and the advantages and disadvantages of multiaxial assessment. Consensus on an item was reached when 75% of experts indicated that they agreed or strongly agreed with the statement. Key results: 36 of 68 eligible participants (52%) responded to the first round. Consensus was reached on 96 items. Using participant feedback, thematic analysis was used to generate 33 additional items for round two. Thirty-one of 36 participants (86%) replied to rounds two and three. In round two, 19 items gained consensus, and in round three, nine items gained consensus. Participants agreed that multiaxial assessment was needed, using a systematic approach to establish the physiological and psychosocial components of FGIDs. Participants were unable to agree on the importance of physical risk factors such as previous surgery and genetic association. Overall, 124 of the 167 items achieved consensus. Conclusion and inferences: The key finding from my study shows that experts agree that multiaxial assessment of FGIDs is needed. I also identified expert agreement on the consideration of psychological risk factors and the importance of the impact of FGID symptoms on daily life. Findings also show that experts disagreed on the impact of physical risk factors, socioeconomic status and spirituality on people with FGIDs. While experts could not agree on genetic and gender-based risk factors, they considered that these areas are important and require further research.
196

Response of Reinforced Concrete Columns Subjected to Impact Loading

Imbeau, Paul January 2012 (has links)
Reinforced Concrete (RC) bridge piers, RC columns along exterior of buildings or those located in parking garages are designed to support large compressive axial loads but are vulnerable to transverse out-of-plane loadings, such as those arising from impacts or explosions. To address a lack of understanding regarding blast and impact response of RC members and the need for retrofit techniques to address deficiencies in existing structures, a multi-disciplinary team including various institutes of the National Research Council and the University of Ottawa has initiated work towards developing a fibre reinforced polymer composite protection system for RC columns subjected to extreme shocks. This thesis will focus on the impact program of the aforementioned project. An extensive literature review was conducted to gain a better understanding of: impact loading and associated dynamic effects; experimental testing of RC members subjected to impact; experimental testing of axially loaded members; and retrofit methods for the protection of RC under impact loading. Five half-scale RC columns were constructed and tested using a drop-weight impact machine and two additional specimens were tested under static loading. Deflections, strain distributions within the columns, impact loads and reaction loads were measured during the testing of the built RC members. Comparisons of experimental datum were established between members with differing levels of axial load and between a retrofitted and a non-retrofitted member. Single-degree-of-freedom analysis was used to obtain the predicted response of certain columns under impact loading allowing for comparisons with experimental data.
197

Využití cirkulujících miRNA jako biomarkerů v diagnostice a terapii revmatických onemocnění / Circulating miRNAs as biomarkers in the diagnosis and treatment of rheumatic diseases

Prajzlerová, Klára January 2021 (has links)
Background: MicroRNAs (miRNAs) are small non-coding single-stranded RNAs involved in the posttranscriptional inhibition of gene expression and thereby regulating all cellular functions. Their dysregulation contributes to the pathophysiology of many diseases, including rheumatic diseases. MiRNAs can also be found extracellularly in body fluids and represent promising diagnostic and prognostic biomarkers. Our study aimed to investigate miRNAs as biomarkers of stage and activity and predictors of therapeutic response of two most common inflammatory rheumatic diseases: spondyloarthritis (SpA) and rheumatic arthritis (RA). Results: We found several circulating miRNAs differentially expressed in SpA patients reflecting the severity of axial involvement and/or disease activity. The decrease in circulating miR-145 in plasma of patients with ankylosing spondylitis 3 months of anti-TNF therapy predicted a good therapeutic response and low disease activity after a year of therapy. Circulating and intracellular expression of miR-125b in peripheral blood mononuclear cells (PBMC) was lower in treatment-naïve patients with early RA than in healthy controls. Baseline expression of miR-125 in PBMC predicted a (non)adequate therapeutic response. We also found the increased expression of miR-451 in PBMC in...
198

Návrh axiálního čerpadla pro zadané parametry / The design of axial pump for given parameters

Stareček, Jakub January 2015 (has links)
This master's thesis contains basic hydraulic calculations, design and optimalization of both the rotor and stator part of the axial pump. There is also included an analysis of the principle and function of hydrodynamic axial pumps. The last part of this work is focusing on the strength calculations and flow simulations using CFD.
199

Finite element analysis of the axial folding bridge

Laux, Christopher D. 16 February 2010 (has links)
<p>The U.S. Army needs a Heavy Dry Support Bridge (HDSB) that can support the Military Load Class (MLC) 96 Heavy Equipment Transporter (HET) tractor trailer carrying an M-I Tank. An existing Axial Folding Bridge (AFB), which was originally designed for MLC 70 loading, has been proposed for load upgrade to demonstrate the feasibility of achieving MLC 96 capacity. This report reviews the upgrade, a finite element model of the bridge, and the actual testing of the bridge to verify the model.</p> <p> The bridge was modeled using the Structural Analysis and Design/Integrated Structural Design System (STAAD-III/ISDS) finite element analysis software. The analysis demonstrated that the existing bridge could be upgraded by simply bolting flat, thin plate elen1ents to the bottom chord of the structure using existing pin plate connector bolt holes and longer bolts. These plates effectively stiffen the bridge structure and maintain a stress level for all elements of the bridge that is no higher for the MLC 96 loading than was experienced for the unrein forced MLC 70 base structure. The modification added 208.7 kg per center section, or an increase in weight of 4.6%, for an increase in load capacity of 37%.</p> <p> A working load static test was conducted on a modified bridge. Four hydraulic actuators applied incremental loading on the bridge. Strain gauge and deflection data were recorded and compared to the analytical model. The model proved to be more flexible than the bridge, but the data showed good correlation in terms of stress ratios between various members. Stress levels were acceptable for the given loading, demonstrating that MLC 96 had successfully been achieved on the bridge.</p> / Master of Science
200

Active flow control at a 1.5-stage low-speed research compressor with varying rotor tip clearance

Künzelmann, M., Urban, R., Mailach, R., Vogeler, K. 03 June 2019 (has links)
The stable operating range of axial compressors is limited by the onset of rotating stall and surge. Mass injection upstream of the tip of an axial compressor rotor is a stability enhancement approach which can be effective in suppressing stall in tip-critical rotors, and thus increasing the operating range of compressors. In this article, investigations on active flow control related to the rotor tip gap sensitivity are discussed. The experiments were performed in a 1.5-stage low-speed research compressor. Measurements at part speed (80 per cent) and full speed (100 per cent) with varying injection rates are discussed. These tests were performed for two rotor tip clearances of 1.3 per cent and 4.3 per cent of rotor blade tip chord. Results on the compressor map, the flow field as well as transient measurements to identify the stall inception are discussed. Supplementary, the numerical results are compared to the experiments based on the configuration with the greatest benefit in operating range enhancement.

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