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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.
331

Elasticita poptávky po pohonných hmotách v České Republice / The Elasticity of Demand for Gasoline: Evidence from the Czech Republic

Lacko, Radoslav January 2019 (has links)
Charles University Faculty of Social Sciences Institute of Economic Studies MASTER'S THESIS The Elasticity of Demand for Gasoline: Evidence from the Czech Republic Author: Bc. Radoslav Lacko Supervisor: Mgr. Petr Polák MSc. Academic Year: 2018/2019 Abstract Studying the price responsiveness of the fuel demand is popular topic among researchers. The price elasticity is used for predicting future tax revenues, or fuel consumption under various situations. This thesis focuses on elasticity estimation for the Czech Republic using high frequency evidence. We use the process of data mining to get the Czech evidence. Observed elasticity differs by the data aggregation level. Estimated long-run elasticity range between −0.38 and −0.68 for gasoline users and between −0.43 and −0.54 for diesel users. Much lower elasticity was estimated in the short-run that confirms economic theory. JEL Classification C51, C55, L71, Q43 Keywords elasticity, fuel, Czech Republic, microdata Author's e-mail rl.lacko@gmail.com Supervisor's e-mail polakpet@gmail.com
332

[en] TWO ESSAYS ON BRAZILIAN TRADE BALANCE: 1999/2005 / [pt] DOIS ENSAIOS SOBRE A BALANÇA COMERCIAL BRASILEIRA: 1999/2005

LIVIO SANTOS DE LEITE RIBEIRO 02 October 2006 (has links)
[pt] De uma posição deficitária antes da desvalorização de 1999, a balança comercial brasileira passou a relativo equilíbrio e, a partir de 2002, a superávits expressivos, relacionados principalmente ao grande crescimento das exportações em um contexto de apreciação cambial. Avaliando o quantum de exportações e importações entre janeiro de 1999 e dezembro de 2005, este trabalho procurou avaliar o desempenho do comércio brasileiro a partir de três proposições gerais: (i) outros fatores podem ter sido tão ou mais importante que o câmbio; (ii) há defasagens na reação do quantum comercializado frente a mudanças nas variáveis explicativas; (iii) há diferenças de comportamento entre o total e as desagregações, tanto no longo como no curto prazo. Em relação às exportações, as elasticidades de demanda estimadas para o longo prazo sugeriram que os preços de exportação e a renda externa tiveram efeito sobre as quantidades, sendo a última relevante também no curto prazo. As elasticidades de oferta, estimadas para o longo prazo, sugeriram que o câmbio, a abertura comercial e os preços de exportação foram determinantes na escolha da firma representativa. Para o período analisado, houve evidência de que a demanda foi mais importante do que a oferta, com os efeitos da renda externa e dos preços de exportação sobrepondose aos da apreciação cambial. Em relação às importações, as elasticidades de demanda estimadas para o longo prazo indicaram maior importância da absorção doméstica e da taxa de câmbio frente a outras variáveis; no curto prazo, a última parece ter sido a variável mais relevante. / [en] From a negative position before the devaluation of 1999, the Brazilian trade balance went to relative equilibrium and, after 2002, to consistent surpluses, mostly related to the huge growth in exports, in a context of exchange rate appreciation. Evaluating exports and imports´ volumes between January 1999 and December 2005, this work seeks to understand Brazilian foreign trade considering three general hypothesis: (i) other variables could have been as or more important than exchange rates; (ii) traded quantum reacts with some delay to changes at the explanatory variables; (iii) aggregated and disaggregated quantum have different behaviors both in long and short run. Regarding exports, long run demand elasticities suggest that export prices and foreign income affect volumes, the latter being also relevant in the short run. Supply elasticities, only for the long run, suggest that exchange rates, trade openness and export prices are relevant for the representative firm s decision. For the period considered, there was evidence that demand is more important than supply, with foreign income and export prices effects overriding exchange rate appreciation. Regarding imports, long run elasticities of demand indicate a greater importance of domestic income and exchange rates compared to other variables. Nonetheless, in the short run, the latter seem to be the most important variable.
333

Análise fotoelástica da distribuição de tensões nos segundos molares inferiores geradas por diferentes mecânicas de verticalização / Photoelastic analysis of stress distribution in lower second molars caused by several uprighting mechanics

Abrão, Andre Felipe 06 June 2014 (has links)
A verticalização de molares inferiores é indicada quando ocorre inclinação mesial dos segundos molares, atribuídas à ausência do primeiro molar. Existem inúmeras metodologias para realização de tal movimento. O objetivo do estudo foi analisar e comparar in vitro, por meio de fotoelasticidade, a distribuição de tensões nos segundos molares inferiores geradas por diferentes métodos de verticalização. Foram avaliados quatro modelos com as seguintes mecânicas: mini-implante, cantiléver, mola em T e mola aberta. As regiões do segundo molar selecionadas para avaliação foram: cervical da raiz mesial, apical da raiz mesial, cervical da raiz distal e apical da raiz distal. A resultante das forças aplicadas foi aferida por meio da quantificação das franjas isocromáticas. Os valores de franjas foram descritos com uso de média e desvio padrão e verificada a concordância/reprodutibilidade entre as avaliações com uso do coeficiente de correlação intraclasse com os respectivos intervalos com 95% de confiança e calculadas as medidas de repetibilidade. Os diferentes tipos de mecânicas foram comparados com uso de teste não paramétrico e quando o teste apresentou significância estatística foram realizadas comparações múltiplas não paramétricas para medidas pareadas com o intuito de verificar entre quais tipos de mecânicas ocorreram diferenças nas ordens das franjas. Os valores diferiram estatisticamente entre os tipos de mecânica utilizados (p < 0,05), exceto na região cervical distal, onde apresentaram-se estatisticamente iguais nos quatro tipos de mecânica (p = 0,112). Na técnica utilizando mini-implante, as maiores tensões foram encontradas na região cervical distal, seguidas de apical da raiz mesial e apical da raiz distal. Na região cervical mesial não foram detectadas tensões. Utilizando o cantiléver, as maiores tensões localizaram-se na região cervical mesial, seguidas de apical da raiz mesial e região cervical distal. Não foram detectadas tensões na apical da raiz distal. Na mola em T, as maiores tensões foram observadas na apical da raiz mesial, seguidas de região cervical da raiz mesial, apical da raiz distal e região cervical distal. Na mola aberta, as maiores tensões foram constatadas na apical da raiz mesial, seguidas de região cervical mesial, região cervical distal e apical da raiz distal. Ao compararem-se as técnicas, foi possível concluir que o mini-implante é a técnica que apresentou as menores tensões e o cantiléver as maiores tensões nas regiões estudadas. / Lower molars uprighting is indicated when mesial inclination of second molars occurs due to the lack of first molars. There are many methodologies to perform such movement. The goal of this research study was to in vitro analyze and compare, by means of photoelasticity, the strain distribution in lower second molars caused by several uprighting methods. Four models with the following mechanics have been evaluated: miniscrews, cantilever, T- loop spring and open coil spring. The second molar areas selected for the evaluation were the following ones: mesial-cervical area, apical area of the mesial root, distal-cervical and apical areas of the distal root. The resultant of forces applied was measured by quantifying isochromatic fringes. The fringe values were described using the mean and the standard deviation values and the agreement/reproducibility among the assessments were verified applying the intraclass correlation coefficient in the respective intervals with 95% confidence. Repeatability measures were calculated. The different types of mechanics were compared applying the nonparametric test and, when the test showed statistical significance, nonparametric multiple comparisons were carried out for paired measurements, aiming at checking in which mechanics fringe differences occur. Values statistically differed among the types of mechanics applied (p < 0.05), except in the distal-cervical area, in which the values were statistically the same for the four types of mechanics (p = 0.112). In the technique using miniscrews, the highest strain values were found in the distal-cervical area, followed by the apical area of the mesial root and the apical area of the distal root. No strain was found in the mesialcervical area. With the cantilever, the highest strains were found in the mesialcervical area, followed by the apical area of the mesial root and the distal-cervical area. No strain was found in the apical area of the distal root. In the T-loop spring, the highest strains were found in the apical area of the mesial root, followed by the cervical area of the mesial root, the apical area of the distal root and the distalcervical area. With the open coil spring, the highest strains were found in the apical area of the mesial root, followed by the mesial-cervical, the distal-cervical and the apical areas of the distal root. When comparing the techniques, it was concluded that the miniscrew showed the lowest stresses and the cantilever the highest stresses in the study regions.
334

Performance Analysis of the Impact of Vertical Scaling on Application Containerized with Docker : Kubernetes on Amazon Web Services - EC2

Midigudla, Dhananjay January 2019 (has links)
Containers are being used widely as a base technology to pack applications and microservice architecture is gaining popularity to deploy large scale applications, with containers running different aspects of the application. Due to the presence of dynamic load on the service, a need to scale up or scale down compute resources to the containerized applications arises in order to maintain the performance of the application. Objectives To evaluate the impact of vertical scaling on the performance of a containerized application deployed with Docker container and Kubernetes that includes identification of the performance metrics that are mostly affected and hence characterize the eventual negative effect of vertical scaling. Method Literature study on kubernetes and docker containers followed by proposing a vertical scaling solution that can add or remove compute resources like cpu and memory to the containerized application. Results and Conclusions Latency and connect times were the analyzed performance metrics of the containerized application. From the obtained results, it was concluded that vertical scaling has no significant impact on the performance of a containerized application in terms of latency and connect times.
335

A study of Douglas-fir anatomical and mechanical properties and their interactions

Bawcombe, Jonathan January 2012 (has links)
Low embodied energy, ability to act as a carbon store and ease of recycling gives forest products an important role within a low carbon built environment. Almost 25 % of the coniferous resource within the South West of England is Douglas-fir, a species reputed for producing high quality timber. Despite this, the region is facing challenges in delivering the resources full potential, a contributing factor to which is a loss of knowledge regarding its quality. The aim of the work presented is to gain an improved understanding of the quality of Douglas-fir grown within the region, from the perspective of uses in structural applications, the factors which influence material quality and their interrelationships. Flexural modulus of elasticity, flexural and compressive strength were determined utilising small clear specimens derived from 1.3 and 8 m heights within 27 trees from six sites across the South West. Results showed a rise in the magnitude of properties with increasing cambial age, particularly so at younger ages. Differences in values were also recorded between stem heights and with rate of growth. These were however less than age related variations. Results compared favourably to those reported in other studies conducted on the species. Utilising SilviScan-3, anatomical properties including density, microfibril angle and cellular dimensions were measured. Significant variations were recorded with cambial age, and in some instances sampling height. The influence of growth rate on anatomical properties was small. Through statistical and composite modelling, microfibril angle was found to be strongly associated with changes in modulus of elasticity within juvenile wood. Within mature wood and for strength properties, density was the controlling factor. It was shown that a moderate proportion of variations in mechanical properties can be accounted for utilising visually identifiable wood characteristics. The new understanding that has been gained through this work presents opportunities for improved utilisation, the implementation of effective management practices and the development of more efficient visual grading techniques.
336

Two-scale homogenisation of partially degenerating PDEs with applications to photonic crystals and elasticity

Cooper, Shane January 2012 (has links)
In this thesis we study elliptic PDEs and PDE systems with e-pcriodic coeffi- cients, for small E, using the theory of two-scale homogenisation. We study a class of PDEs of partially degenerating type: PDEs with coefficients that are not uniformly elliptic with respect to E, and become degenerate in the limit E -t O. We review a recently developed theory of homogenisation for a general class of partially degenerating PDEs via the theory of two-scale convergence, and study two such problems from physics. The first problem arises from the study of a linear elastic composite with periodically dispersed inclusions that are isotropic and (soft' in shear: the shear modulus is of order E2. By passing to the two- scale limit as E -t 0 we find the homogenised limit equations to be a genuinely two-scale system in terms of both the macroscopic variable x and the micro- scopic variable y. We discover that the corresponding two-scale limit solutions must satisfy the incompressibility condition in y and therefore the composite only undergoes microscopic deformations when a (microscopically rotational' force is applied. We analyse the corresponding limit spectral problem and find that, due to the y-incompressibility, the spectral problem is an uncoupled two-scale prob- lem in terms of x and y. This gives a simple representation of the two-scale limit spectrum. We prove the spectral compactness result that states: the spectrum of the original operator converges to the spectrum of the limit operator in the sense of Hausdorff. The second problem we study is the propagation of electro- magnetic waves down a photonic fibre with a periodic cross section. We seek solutions to Maxwell's equations, propagating down the waveguide with wave number k E2-close to some (critical' value. In this setting, Maxwell's equations are reformulated as a partially degenerating PDE system with z-periodic coeffi- cients. Using the theory of homogenisation we pass to the limit as E -t 0 to find a non-standard two-scale homogenised limit and prove that the spectral compact- ness result holds. We finally prove that there exist gaps in the limit spectrum for two particular examples: a one-dimensionally periodic 'multilayer ' photonic crystal and a two-dimensionally periodic two-phase photonic crystal with the in- clusion phase consisting of arbitrarily small circles. Therefore, we prove that these photonic fibres have photonic band gaps for certain k.
337

Theoretical and numerical investigation of the equilibrium shape of curved strips and tapered rods

Naicu, Dragos January 2016 (has links)
The bending of elastic strips and rods is a field of research that continues to offer new possibilities for exploration. This dissertation focuses on two distinct problems within this context. These are the search for the equilibrium shape of thin inextensible elastic strips, such as a M�öbius strip made out of paper, and the optimal shape of tapered columns that are stable against buckling. A theoretical approach based on the principle of virtual work is used to investigate both problems. This produces novel governing non-linear differential equations that describe both equilibrium and form. In order to discover the equilibrium shapes, numerical algorithms are developed that are based on Dynamic Relaxation. There are two ways in which they are used, one as an explicit form-finding tool, and the other as a way of solving differential equations. Results are provided that extend current theoretical models. The numerical schemes produce three-dimensional shapes for strips, going beyond the canonical Möbius strip, and solution shapes for tapered columns made from non-linear elastic materials. With the aid of analytical and numerical tools, finding the form of the M�öbius strip and the tallest possible column are interesting challenges in the search for new shapes that are driven by physical and material rules. These have applicability in structural engineering, architecture, nano-technology and even artistic endeavour.
338

Homogenization of an elastic-plastic problem.

Onofrei, Daniel T 30 April 2003 (has links)
This project presents the homogenization analysis for a static contact problem with slip dependent friction between an elastic body and a rigid foundation. The homogenization for the static eigenvalue problem associated to this model is studied. We prove that the eigenvalues are of order epsilon. We obtain the limit problem for the contact model. The analysis is carried out by using the Gamma-convergence theory.
339

[en] TENSIONS GENERATED BY SELF-INDUCED GRAVITATIONAL ACTION ON A SOLID SPHERE: APPLICATIONS TO STUDY THE DISTRIBUTION OF DENSITY AND ELASTICITY OF THE PLANETS / [pt] TENSÕES GERADAS POR AÇÃO GRAVITACIONAL AUTO-INDUZIDA EM UMA ESFERA MACIÇA: APLICAÇÕES PARA O ESTUDO DA DISTRIBUIÇÃO DE DENSIDADES E ELASTICIDADE DOS PLANETAS

CARLOS FERNANDO MARTINS PAMPLONA 27 March 2019 (has links)
[pt] No presente trabalho, uma análise da distribuição de densidades em corpos esféricos de grandes dimensões é feita com base nas tensões geradas pela ação gravitacional. Verificou-se que uma expressão elítica para a distribuição radial de massas específicas na forma p=po[1-a(r/R)(2)](1/2) fornece resultados razoáveis para as propriedades mecânicas no interior da Terra. Partindo dessa informação, diversos modelos para a distribuição de densidades dos planetas terrestres e Lua são analisados e propostos, baseados na hipótese de que os materiais dos núcleos desses astros são semelhantes. O valor do momento de inércia bem como do diâmetro do núcleo pesado dos planetas interiores do Sistema Solar são estimados, a partir da análise feita. Os modelos foram elaborados admitindo a variação das propriedades mecânicas com a pressão, bem como levando em consideração a existência de uma descontinuidade na distribuição de densidades, sendo os resultados comparados com as informações sismológicas fornecidas pela Geodesia e Selenodesia. Esses resultados são extendidos aos demais planetas terrestres com o intuito de obter novas informações sobre esses astros dos quais pouco se conhece sobre a natureza de seu interior. / [en] In the present work an analysis of the density distribution in large spherical bodies is made based on the stresses generated by gravitational action. Is is found that an eliptical expression for the radial density distribution in the form of the equation p=po[1-a(r/R)(2)](1/2) give reasonable results for the mechanical properties of earth interior. Starting with this assumption, several models for density distribution for terrestrial planets and earth s moon are analysed and proposed, based on the assumption of similiarity of core materials of these bodies. The value of moment of inertia as well as the diameter of the core of the inner planets of the solar system are estimated from those analyses. The models were developed admiting variable mechanical properties with pressure, as well as discontinuity on the density distribution, and the results compared with seismic data from geodesy and selenodesy. Extension of those results for other terrestrial planets were made in an attempt to obtain new informations about these planets, for wich little is know about its interior.
340

A Tension Please

VALLEJOS CASTRO, GABRIELA January 2014 (has links)
This degree work is about the exploration of the stretch in textile materials by using cartridge pleats as a method to create weight and thereby create tension. Through research in materials and stretch fabrics versus heavier woven textiles the work strives for expressions in movement as well as new ways of combining lightness and weight. / Program: Modedesignutbildningen

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