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Study of the surface hardness and modulus of elasticity of conventional and microwave-cured acrylic resins

BINDO, Márcio José Fraxino; NAKAMAE, Atlas Edson Moleros; SANTOS, Lydia de Brito; ISHIKAWA, Karin Hitomi; GUARNIERI, Tatiana de Carvalho; TAMAKI, Regina
Fonte: Sociedade Brasileira de Pesquisa Odontológica Publicador: Sociedade Brasileira de Pesquisa Odontológica
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
35.94%
The aim of this study was to evaluate the following acrylic resins: Clássico®, QC-20® and Lucitone®, recommended specifically for thermal polymerization, and Acron MC® and VIPI-WAVE®, made for polymerization by microwave energy. The resins were evaluated regarding their surface nanohardness and modulus of elasticity, while varying the polymerization time recommended by the manufacturer. They were also compared as to the presence of water absorbed by the samples. The technique used was nanoindentation, using the Nano Indenter XP®, MTS. According to an intra-group analysis, when using the polymerization time recommended by the manufacturer, a variation of 0.14 to 0.23 GPa for nanohardness and 2.61 to 3.73 GPa for modulus of elasticity was observed for the thermally polymerized resins. The variation for the resins made for polymerization by microwave energy was 0.15 to 0.22 GPa for nanohardness and 2.94 to 3.73 GPa for modulus of elasticity. The conclusion was that the Classico® resin presented higher nanohardness and higher modulus of elasticity values when compared to those of the same group, while Acron MC® presented the highest values for the same characteristics when compared to those of the same group. The water absorption evaluation showed that all the thermal polymerization resins...

Relationship between birthweight and arterial elasticity in childhood

RONDÓ, Patrícia Helen de Carvalho; LEMOS, Jesuana Oliveira; PEREIRA, Joilane Alves; OLIVEIRA, Julicristie Machado de; INNOCENTI, Jose Roberto
Fonte: London Publicador: London
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
35.9%
There is a considerable debate about the potential influence of fetal programming on cardiovascular diseases in adulthood. In the present prospective epidemiological cohort study, the relationship between birthweight and arterial elasticity in 472 children between 5 and 8 years of age was assessed. LAEI (large artery elasticity index), SAEI (small artery elasticity index) and BP (blood pressure) were assessed using the HDI/PulseWave CR-2000 CardioVascular Profiling System. Blood concentrations of glucose, total cholesterol and its fractions [LDL (low-density lipoprotein)-cholesterol and HDL (high-density lipoprotein)-cholesterol] and triacylglycerols (triglycerides) were determined by automated enzymatic methods. Insulin was assessed by a chemiluminescent method, insulin resistance by HOMA (homoeostasis model assessment) and CRP (C-reactive protein) by immunonephelometry. Two linear regression models were applied to investigate the relationship between the outcomes, LAEI and SAEI, and the following variables: birthweight, gestational age, glucose, LDL-cholesterol, HDL-cholesterol, triacylglycerols, insulin, CRP, HOMA, age, gender, waist circumference, per capita income, SBP (systolic BP) and DBP (diastolic BP). LAEI was positively associated with birthweight (P=0.036)...

The impact of maternal cortisol concentrations on child arterial elasticity

RONDO, P. H. C.; PEREIRA, J. A.; LEMOS, J. O.; FERREIRA, R. F.
Fonte: CAMBRIDGE UNIV PRESS Publicador: CAMBRIDGE UNIV PRESS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
35.94%
Epidemiological studies suggest that glucocorticoid excess in the fetus may contribute to the pathophysiology of cardiovascular diseases in adulthood. However, the impact of maternal glucocorticoid on the cardiovascular system of the offspring has not been much explored in studies involving humans, especially in childhood. The objective of this study was to assess the influence of maternal cortisol concentrations on child arterial elasticity. One hundred and thirty pregnant women followed from 1997 to 2000, and respective children 5-7 years of age followed from 2004 to 2006 were included in the study. Maternal cortisol was determined in saliva by an enzyme immunoassay utilizing the mean concentration of nine samples of saliva. Arterial elasticity was assessed by the large artery elasticity index (LAEI; the capacitive elasticity of large arteries) by recording radial artery pulse wave, utilizing the equipment HDI/PulseWave CR-2000 Cardiovascular Profiling System (R). The nutritional status of the children was determined by the body mass index (BMI). Insulin concentration was assessed by chemiluminescence, and insulin resistance by the homeostasis model assessment. Blood glucose, total cholesterol and fractions (LDL-c and HDL-c) and triglyceride concentrations were determined by automated enzymatic methods. The association between maternal cortisol and child arterial elasticity was assessed by multivariate linear regression analysis. There was a statistically significant association between maternal cortisol and LAEI (P=0.02)...

Estudo sobre a variabilidade do módulo de deformação do concreto associada a fatores intrínsecos à produção do material.; Study of the variability of the concrete modulus of elasticity associated to intrinsic factors related to the material production.

De Marchi, Renata D'Agostino
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/10/2011 PT
Relevância na Pesquisa
35.97%
Em função da especificação do módulo de elasticidade ou módulo de deformação do concreto ser cada vez mais frequente, se faz necessário o conhecimento da variabilidade desta propriedade, relacionada ao processo de produção, de modo a tornar mais confiável sua avaliação e que possibilite melhores condições no controle de produção para o atendimento aos requisitos associados a esta propriedade. Várias pesquisas têm comprovado que a variabilidade das propriedades mecânicas dos materiais de construção obedece a processos aleatórios. Portanto, os métodos de segurança no projeto estrutural devem estar fundamentados no conceito da teoria das probabilidades e não em métodos deterministas. Isso já acontece para a determinação da resistência à compressão, conforme estabelecido pela ABNT NBR 12655 (2006). A presente dissertação tem como objetivo principal estudar o controle experimental do módulo estático de deformação do concreto, mostrando a influência da variação dos materiais constituintes do concreto, dentro da realidade de uma Central de Concreto. Também objetiva apresentar uma discussão da aplicabilidade do conceito semiprobabilístico das normas nacionais de projeto...

Relação entre elasticidade arterial e outros marcadores de risco cardiovascular em indivíduos com HIV/aids em terapia antirretroviral; Relationship between arterial elasticity and other markers of cardiovascular risk in individuals with HIV/AIDS on antiretroviral therapy.

Pontilho, Patricia de Moraes
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 30/11/2012 PT
Relevância na Pesquisa
35.96%
Introdução: Existe crescente interesse em identificar marcadores de risco para eventos cardiovasculares em pacientes com HIV/aids. Atualmente observa-se alteração do perfil epidemiológico desses pacientes, com diminuição da mortalidade por infecção e comorbidades e aumento por eventos cardiovasculares. A elasticidade arterial, principalmente dos pequenos vasos, tem sido investigada como alteração precoce de evento cardiovascular. Objetivo: Avaliar a relação entre elasticidade arterial e outros indicadores de risco cardiovascular como fatores demográficos e socioeconômicos, hábitos de vida, estado nutricional e marcadores inflamatórios. Métodos: Foram selecionados aleatoriamente 132 indivíduos voluntários em tratamento regular com antirretrovirais em ambulatório especializado em HIV/aids, com idade entre 19 e 59 de ambos os sexos. A elasticidade arterial dos grandes vasos (LAEI) e pequenos vasos (SAEI) foi investigada pelo equipamento HDI/ PulseWaveTM CR-2000 Cardio Vascular Profiling System®. Foram determinados colesterol total e frações, triglicérides, proteína C-reativa, fibrinogênio, medidas antropométricas e de avaliação de composição corporal, fumo, consumo de bebidas alcoólicas, uso de drogas...

Efeito da ingestão de chocolate e erva mate na elasticidade arterial de indivíduos com HIV/aids em terapia antirretroviral; The effect of chocolate and yerba maté intake on arterial elasticity of HIV/aids patients on antiretroviral therapy

Teixeira, Andrea Mariana Nunes da Costa
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/09/2013 PT
Relevância na Pesquisa
35.9%
Introdução - Estudos mostram maior ocorrência de complicações cardiovasculares na população HIV/aids. Alguns estudos envolvendo animais e indivíduos saudáveis ou com outras doenças observaram benefícios no consumo de chocolate e erva mate na função endotelial e vasodilatação. Objetivo Avaliar o efeito da ingestão de chocolate e erva mate na elasticidade arterial de indivíduos com HIV/aids em terapia antirretroviral. Métodos Ensaio clínico cruzado, aleatorizado e duplo-cego, envolvendo 89 indivíduos com HIV/aids entre 19 e 59 anos, em tratamento regular com antirretrovirais por no mínimo 6 meses, e carga plasmática do HIV <500 cópias/ml. Os indivíduos receberam suplementação diária com aproximadamente 65g de chocolate amargo, 3g de erva mate ou respectivos placebos por 15 dias, com washout de igual tempo entre as intervenções. A aferição da elasticidade arterial foi realizada por análise do formato da onda de pulso com o equipamento HDI/PulseWaveTM CR-2000®. Também foram avaliados: composição corporal, glicemia, perfil lipídico, proteína C-reativa e concentração plasmática de espécies reativas ao ácido tiobarbitúrico (TBARS). As respostas entre tratamentos foram avaliadas por ANOVA e por teste t de Student pelo Stata® 11.0...

Estimativa econométrica das elasticidades renda e preço da demanda por gás natural para o setor industrial brasileiro; Econometric Forecasts: A Study on Long-Term Price and Income Elasticity for Natural Gas in the Brazilian Industrial Sector

Cabral, Renata Fonseca
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 11/06/2013 PT
Relevância na Pesquisa
35.92%
Este trabalho tem como objetivo estimar a elasticidade renda e preço da demanda por gás natural no Brasil para o setor industrial brasileiro. O segmento de consumo industrial representa cerca de dois terços do consumo de gás natural no país, destacando sua importância estratégica na elaboração de política energética relacionada ao gás. Este trabalho apresenta também o incremento nas trocas internacionais de gás natural e a perspectiva de aumento do uso desse energético no Brasil e no mundo. Alguns desafios ainda se colocam para a efetiva globalização dessa indústria, como: a necessidade de realização de investimentos em infraestrutura de produção, transporte e distribuição; o aprimoramento do acesso às principais reservas do hidrocarboneto; e as incertezas com relação à evolução da demanda. Utiliza-se o estudo estatístico econométrico para estimar as elasticidades preço e renda, ou seja, para investigar como a demanda industrial brasileira reage frente a um aumento ou diminuição de preço do gás e das variações na renda disponíveis no Brasil. Como proxy da renda industrial utilizam-se os dados do PIB industrial brasileiro. Após identificar que as séries estudadas eram não estacionárias, optou-se pela utilização do conceito de cointegração. Os resultados obtidos por meio do referido modelo mostraram que a demanda estudada é muito mais sensível a variações do preço do gás natural do que a variações na renda. Desse modo...

The position effect of structural Eucalyptus round timber on the flexural modulus of elasticity

Christoforo, André L.; Panzera, Túlio H.; Batista, Fabiano B.; Borges, Paulo H. R.; Lahr, Francisco A. R.; Franco, Claudenir F.
Fonte: Associação Brasileira de Engenharia Agrícola (SBEA) Publicador: Associação Brasileira de Engenharia Agrícola (SBEA)
Tipo: Artigo de Revista Científica Formato: 1219-1225
ENG
Relevância na Pesquisa
35.9%
A madeira roliça possui grande emprego nas construções civis, desempenhando a função de vigas, colunas, fundações, postes para distribuição de energia elétrica, entre outras, apresentando a vantagem de não ser processada, como é o caso da madeira serrada. O projeto envolvendo elementos roliços requer, além de outras variáveis estruturais, o conhecimento do módulo de elasticidade. No Brasil, os documentos normativos que tratam da determinação das propriedades de rigidez e resistência para peças roliças de madeira estão em vigência há mais de vinte anos sem revisão técnica. A madeira roliça, por geralmente possuir eixo com curvatura não nula, pode apresentar, segundo a posição da peça no ensaio de flexão, valores diferentes do módulo de elasticidade. Este trabalho tem como objetivo analisara influência da posição de peças roliças de madeira de Eucalyptus grandis na determinação do módulo de elasticidade na flexão. O ensaio de flexão utilizado é o de três pontos, sendo cada peça avaliada em duas posições distintas, definidas mediante o giro da seção transversal em torno do eixo. Os resultados encontrados indicam a necessidade do ensaio de flexão em, pelo menos, duas posições distintas da peça.; Round timber has great use in civil construction...

Analysis of bed joint influence on masonry modulus of elasticity

Zavalis, R.; Jonaitis, B.; Lourenço, Paulo B.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2014 ENG
Relevância na Pesquisa
35.95%
The means of determining the modulus of elasticity presented in technical literature often underestimate factors such as the influence of mechanical properties of the bed joint mortar and the influence of contact zone of the masonry unit and mortar on the elasticity modulus. Research carried out by the authors show that the modulus of elasticity of the bed joint considering influence of the contact zone (effective modulus of elasticity) is 3 to 25 times less than mortar modulus of elasticity, set by experimenting with samples in accordance with the requirements of the EN 1015-11 standard. The modulus of elasticity depends on the properties of mortar, masonry unit and bed joint thickness. This article discusses deformation properties of mortar in bed joints of calcium silicate block masonry. An analytical model determining mortar joint deformation properties is proposed, which considers a shift in mortar properties and the contact zone between mortar and the masonry unit. The masonry elasticity modulus values have been estimated applying the suggested method and comparing the results to the experimental values.

Automatic elasticity in OpenStack

Vilaça, Ricardo; Matos, Miguel; Beernaert, Leander; Oliveira, Rui Carlos Mendes de
Fonte: ACM; ACM Publicador: ACM; ACM
Tipo: Conferência ou Objeto de Conferência
Publicado em //2012 ENG
Relevância na Pesquisa
35.9%
Cloud computing infrastructures are the most recent ap- proach to the development and conception of computational systems. Cloud infrastructures are complex environments with various subsystems, each one with their own challenges. Cloud systems should be able to provide the following fun- damental property: elasticity. Elasticity is the ability to automatically add and remove instances according to the needs of the system. This is an requirement for pay-per-use billing models. Various open source software solutions allow companies and institutions to build their own Cloud infrastructure. How- ever, in most of these, the elasticity feature is quite imma- ture. Monitoring and timely adapting the active resources of a Cloud computing infrastructure is key to provide the elasticity required by diverse, multi tenant and pay-per-use business models. In this paper, we propose Elastack, an automated monitor- ing and adaptive system, generic enough to be applied to existing IaaS frameworks and intended to enable the elastic- ity they currently lack. Our approach offers any Cloud in- frastructure the mechanisms to implement automated mon- itoring and adaptation as well as the flexibility to go beyond these. We evaluate Elastack by integrating it with the Open- Stack and showing how easy it is to add these important features with a minimum...

The position effect of structural Eucalyptus round timber on the flexural modulus of elasticity

Christoforo,André L; Panzera,Túlio H; Batista,Fabiano B; Borges,Paulo H. R; Lahr,Francisco A. R; Franco,Claudenir F
Fonte: Associação Brasileira de Engenharia Agrícola Publicador: Associação Brasileira de Engenharia Agrícola
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
Relevância na Pesquisa
35.9%
Round timber has great use in civil construction, performing the function of beams, columns, foundations, poles for power distribution among others, with the advantage of not being processed, such as lumber. The structural design of round timber requires determining the elastic properties, mainly the modulus of elasticity. The Brazilian standards responsible for the stiffness and strength determination of round timber are in effect for over twenty years with no technical review. Round timber, for generally present an axis with non-zero curvature according to the position of the element in the bending test, may exhibit different values of modulus of elasticity. This study aims to analyze the position effect of Eucalyptus grandis round timber on the flexural modulus of elasticity. The three-point bending test was evaluated in two different positions based on the longitudinal rotation of the round timber element. The results revealed that at least two different positions of the round timber element are desired to obtain significant modulus of elasticity.

A cross-country non parametric estimation of the returns to factors of production and the elasticity of scale

Marquetti,Adalmir
Fonte: Nova Economia Publicador: Nova Economia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2007 EN
Relevância na Pesquisa
35.94%
This paper employs local regression to estimate the output elasticity with respect to labor, human capital, physical capital and the elasticity of scale for 90 countries in 1985 and 1995. The results support the hypotheses of constant returns to scale to factors and decreasing returns to accumulable factors. The low capital-labor ratio countries have important differences in factor elasticities in relation to other countries. The augmentation of the production function by human capital did not reduce the elasticity of physical capital as suggested by Mankiw, Romer and Weil (1992). Moreover, it is investigated if the factors shares are really equal to their output elasticity. The wage share raises with the capital labor ratio and the sum of the output elasticity of labor and human capital is below the wage share for high capital labor ratio countries, happening the inverse for low capital labor ratio countries. It indicates the presence of externalities, or imperfect competition or that the marginal theory of distribution is inaccurate.

Study of the surface hardness and modulus of elasticity of conventional and microwave-cured acrylic resins

Bindo,Márcio José Fraxino; Nakamae,Atlas Edson Moleros; Santos,Lydia de Brito; Ishikawa,Karin Hitomi; Guarnieri,Tatiana de Carvalho; Tamaki,Regina
Fonte: Sociedade Brasileira de Pesquisa Odontológica - SBPqO Publicador: Sociedade Brasileira de Pesquisa Odontológica - SBPqO
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2009 EN
Relevância na Pesquisa
35.94%
The aim of this study was to evaluate the following acrylic resins: Clássico®, QC-20® and Lucitone®, recommended specifically for thermal polymerization, and Acron MC® and VIPI-WAVE®, made for polymerization by microwave energy. The resins were evaluated regarding their surface nanohardness and modulus of elasticity, while varying the polymerization time recommended by the manufacturer. They were also compared as to the presence of water absorbed by the samples. The technique used was nanoindentation, using the Nano Indenter XP®, MTS. According to an intra-group analysis, when using the polymerization time recommended by the manufacturer, a variation of 0.14 to 0.23 GPa for nanohardness and 2.61 to 3.73 GPa for modulus of elasticity was observed for the thermally polymerized resins. The variation for the resins made for polymerization by microwave energy was 0.15 to 0.22 GPa for nanohardness and 2.94 to 3.73 GPa for modulus of elasticity. The conclusion was that the Classico® resin presented higher nanohardness and higher modulus of elasticity values when compared to those of the same group, while Acron MC® presented the highest values for the same characteristics when compared to those of the same group. The water absorption evaluation showed that all the thermal polymerization resins...

INFLUÊNCIA DO TAMANHO DO CORPO DE PROVA NOS RESULTADOS DE ENSAIOS DE MÓDULO DE DEFORMAÇÃO E RESISTÊNCIA À COMPRESSÃO E SUAS CORRELAÇÕES PARA CONCRETOS PRODUZIDOS EM GOIÂNIA - GO; INLUENCE OF THE SIZE OF THE SPECIMEN IN THE RESULTS OF THE TESTS OF MODULUS OF ELASTICITY AND COMPRESSIVE STRENGTH AND THEIR CORRELATIONS FOR CONCRETE MADE IN GOIÂNIA GO

MARTINS, Danilo Gomes
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Engenharia Civil; Engenharias Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Engenharia Civil; Engenharias
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
35.96%
Even though the different sizes of cylindrical specimens for tests in concrete are standardized to get the simple compressive strength and the modulus of elasticity, this factor is not usually studied in most researches. So, the goal of this thesis was to evaluate the influence of the size of the specimens in the initial tangent modulus of elasticity (Eci) and in the compressive strength (fc), correlate the values of fc and Eci, and compare the values of modulus of elasticity that were estimated by the equations proposed by the Brazilian code (NBR 6118/2003) and by the American norm (ACI 318/2002). Concretes with three levels of strength were used after 28 days: 25MPa, 30MPa and 40MPa. They were all proportionally mixed with materials of the region and supplied by only one concrete batching plant of Goiânia GO. The tests of compressive strength and initial tangent modulus of elasticity were done in cylindrical specimens of 100 x 200 mm and 150 x 300 mm after 28 days. The samples were collected during the delivery of the concrete in the construction sites. For each truck, ten specimens were molded, five of 100 x 200 mm and five of 150 x 300 mm. Of the 600 specimens that were molded, 240 tests of compressive strength and 360 tests of modulus of elasticity were done. The cure was in a tank with water saturated with limestone. After the tests were done...

Influência do tipo de medição na determinação do módulo estático de elasticidade do concreto; Influence of Type of Measurement in Determining the Static Module of Elasticity of Concrete

ARAÚJO, Suélio da Silva
Fonte: Universidade Federal de Goiás; BR; UFG; Mestrado em Engenharia Civil; Engenharias Publicador: Universidade Federal de Goiás; BR; UFG; Mestrado em Engenharia Civil; Engenharias
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
35.92%
The knowledge of the compressive strength and static modulus of elasticity is fundamental to the study of deformations of concrete, since deformations can cause cracks that compromise both the structural behavior of the element and serve as an entry to deleterious agents. For purposes of correlating values of compressive strength and static modulus of elasticity of concrete, cylinders were cast with different strengths, different types of strain measurements were taken, different specimen sizes and the loading speed of the testing machine. The specimens were tested at the age of 28 days to determine the compressive strength and static module of elasticity according to ABNT NBR 8522:2008, using different types of strain measurement devices: two mechanical dial indicators, surface bonded strain gages, clip gauges and LVDT (Linear Variable Differential Transducer). Two hundred and fifty eight specimens were cast with dimensions 150 mm x 300 mm and 100 mm x 200 mm using conventional normal strength concrete (NC - Class C30) and high strength concrete (HSC - Class C60). The experimental program was divided into two stages. First the static modulus of elasticity of concrete was measured to evaluate the accuracy of the method using different measuring devices and the accuracy of the method to a loading speed of 0.6 MPa/s. Then...

Price Elasticity of Nonresidential Demand for Energy in South Eastern Europe

Iimi, Atsushi
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
EN_US
Relevância na Pesquisa
35.92%
Recent volatility in international energy prices has revealed South Eastern Europe as one of the most vulnerable regions to such external shocks. Under the current global economic downturn, in addition, the region s energy-intensive industries are faced with the challenge of the weakening demand for their outputs. This paper casts light on the relationship between the price and the demand for energy. Based on firm level data, it is shown that the price elasticity of industrial energy demand is about -0.4 on average. There are a number of data issues to interpret the results correctly. But Albania and Macedonia are systematically found to have a relatively elastic demand for energy on the order of -0.7 to -0.8. In these countries, therefore, price adjustments would be one of the effective policy options to balance demand with supply during the period of energy crisis. In other countries, the demand response would be much weaker; pricing cannot be the only solution. Other policy measures, such as facilitation of firm energy efficiency and improvements in the quality of infrastructure services...

Four simplified gradient elasticity models for the simulation of dispersive wave propagation

Askes, H.; Metrikine, A.; Pichugin, A.; Bennett, T.
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
Publicado em //2008 EN
Relevância na Pesquisa
35.9%
Gradient elasticity theories can be used to simulate dispersive wave propagation as it occurs in heterogeneous materials. Compared to the second-order partial differential equations of classical elasticity, in its most general format gradient elasticity also contains fourth-order spatial, temporal as well as mixed spatial-temporal derivatives. The inclusion of the various higher-order terms has been motivated through arguments of causality and asymptotic accuracy, but for numerical implementations it is also important that standard discretization tools can be used for the interpolation in space and the integration in time. In this paper, we will formulate four different simplifications of the general gradient elasticity theory. We will study the dispersive properties of the models, their causality according to Einstein and their behavior in simple initial/boundary value problems.; H. Askes, A.V. Metrikine, A.V. Pichugin and T. Bennett

Determinação da densidade mineral e da elasticidade óssea após a aplicação de ondas de choque extracorpóreas no terceiro metacarpiano de equinos atletas; Mineral density and bone elasticity determination after extracorporeal shock waves application in third metacarpus of athlete equines

Pyles, Marcelo Damas; Fonseca, Brunna Patrícia Almeida da; Machado, Vânia Maria Vasconcelos; Yamada, Ana Lúcia Miluzzi; Alves, Ana Liz Garcia
Fonte: Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia Publicador: Universidade de São Paulo. Faculdade de Medicina Veterinária e Zootecnia
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; ; Formato: application/pdf
Publicado em 01/01/2011 POR
Relevância na Pesquisa
35.9%
Objetivou-se neste estudo avaliar os efeitos da aplicação de ondas de choque extracorpóreas (ESWT) no terceiro metacarpiano de equinos hígidos através da determinação da elasticidade óssea. Foram utilizados 20 equinos Puro Sangue Inglês, machos e fêmeas, com dois anos de idade, em início de treinamento e selecionados quanto ao estado de higidez. No início do experimento (D0), todos os animais foram submetidos à avaliação da elasticidade óssea do terceiro metacarpiano. Os animais foram divididos em dois grupos (Grupo Controle - GC e Grupo Experimental - GE). A aplicação das ESWT foi realizada no membro torácico direito dos animais do GE, na região coincidente à da avaliação da elasticidade óssea. Foi utilizado aparelho para terapia de ondas extracorpóreas com densidade de fluxo de energia de 0,15mJ/mm² e 2000 pulsos com probe E6R20, com característica do foco da onda de choque de 20 mm. A ESWT foi repetida a cada 21 dias totalizando três sessões (D0, D21 e D42). A análise da determinação da elasticidade óssea foi realizada no D0, D21, D42 e D72. A média da velocidade ultrassonográfica diferiu entre os grupos no D21, D42 e D72, sendo que os animais do GE apresentaram menor densidade mineral óssea após as aplicações das ESWT. Houve igualmente...

Mapping Myocardial Elasticity with Intracardiac Acoustic Radiation Force Impulse Methods

Hollender, Peter J.
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Dissertação
Publicado em //2014
Relevância na Pesquisa
35.94%

Implemented on an intracardiac echocardiography transducer, acoustic radiation force methods may provide a useful means of characterizing the heart's elastic properties. Elasticity imaging may be of benefit for diagnosis and characterization of infarction and heart failure, as well as for guidance of ablation therapy for the treatment of arrhythmias. This thesis tests the hypothesis that with appropriately designed imaging sequences, intracardiac acoustic radiation force impulse (ARFI) imaging and shear wave elasticity imaging (SWEI) are viable tools for quantification of myocardial elasticity, both temporally and spatially. Multiple track location SWEI (MTL-SWEI) is used to show that, in healthy in vivo porcine ventricles, shear wave speeds follow the elasticity changes with contraction and relaxation of the myocardium, varying between 0.9 and 2.2 m/s in diastole and 2.6 and 5.1 m/s in systole. Infarcted tissue is less contractile following infarction, though not unilaterally stiffer. Single-track-location SWEI (STL-SWEI) is proven to provide suppression of speckle noise and enable improved resolution of structures smaller than 2 mm in diameter compared to ARFI and MTL-SWEI. Contrast to noise ratio and lateral edge resolution are shown to vary with selection of time step for ARFI and arrival time regression filter size for STL-SWEI and MTL-SWEI.

In 1.5 mm targets...

A cross-country non parametric estimation of the returns to factors of production and the elasticity of scale; A cross-country non parametric estimation of the returns to factors of production and the elasticity of scale

Marquetti, Adalmir
Fonte: Nova Economia; Nova Economia Publicador: Nova Economia; Nova Economia
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 05/06/2009 POR
Relevância na Pesquisa
35.94%
This paper employs local regression to estimate the output elasticity with respect to labor, human capital, physical capital and the elasticity of scale for 90 countries in 1985and 1995. The results support the hypotheses of constant returns to scale to factors and decreasing returns to accumulable factors. The low capital-labor ratio countries have important differences in factor elasticities in relation to other countries. The augmentation of the production function by human capital did not reduce the elasticity of physical capital as suggested by Mankiw, Romer and Weil (1992). Moreover, it is investigated if thefactors shares are really equal to their output elasticity. The wage share raises with the capital labor ratio and the sum of the output elasticity of labor and human capital is below the wage share for high capital labor ratio countries, happening the inverse for low capital labor ratio countries. It indicates the presence of externalities, or imperfect competition or that the marginal theory of distribution is inaccurate.; Este artigo utiliza regressão local para estimar a elasticidade do produto em relação ao trabalho, capital  humano, capital físico e a elasticidade de escalapara 90 países em 1985 e 1995. Os resultados corroboram a hipótese de retorno constante de escala.  Contudo...