Thesis (M.C.R.P.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 70-72).

Thesis (M.C.E.)--University of Delaware, 2007. / Principal faculty advisor: James T. Kirby, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Thesis (Ph. D.) University of Missouri-Columbia, 2006. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 7, 2007) Includes bibliographical references.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed May 23, 2007). PDF text: v, 326 p. : ill. (some col.) ; 3.85Mb UMI publication number: AAT 3237557. Includes bibliographical references. Also available in microfilm and microfiche formats.

[pt] Este trabalho apresenta uma técnica numérica. baseada no Método de Decomposição do Operador (Operator Splitting Method) e algorítimos sequenciais associados (product formula algorithm) para simular o fenômeno de propagação de ondas em barras elasto-viscoplásticas. Este método tem boas propriedades de estabilidade e preciaão mesmo quando um esquema explícito de baixa ordem é utilizado na integração temporal. Esta técnica numérica é usada para simular carregamentos cíclicos de alta frequência em barras de aço austenítico a altas temperaturas. / [en] The present work presents a numerical technique ( based on the Operator Split Method associated with product formula algorithm ) for simulating the wave propagation phenomenon in bars with any kind of elastic-viecoplastic oonstitutive equations. This method has very good properties of stability and precision even if explicit time evolution schemes are used. This numerical technique is used to simulate high frequency cyclic loadings in austenitic steel bars at high temperatures.

[pt] É considerado neste trabalho um modelo mecânico para simulação do comportamento anisotérmico de materiais inelásticos submetidos a carregamentos dinâmicos. O trabalho tem como motivação o estudo, através de simulações numéricas, dos efeitos da propagação da onda de tensão no meio, e de fenômenos como o aquecimento e a degradação local induzida pelas deformações inelásticas. A equação da energia com seus termos de acoplamentos entre os efeitos térmico e mecânico é incluída na modelagem. A teoria constitutiva utilizada baseia-se na mecânica do dano contínuo no contexto de variáveis internas sendo particularizada para materiais elastoviscoplásticos e aplicado ao caso de uma barra solicitada axialmente. O sistema não linear de equações diferenciais parciais resultante do modelo é resolvido através do uso uma técnica de decomposição do operador que permite a aplicação de procedimentos numéricos clássicos de solução. Dentre estes procedimentos, foi usado no trabalho, o método de Glimm. Exemplos numéricos retratando a evolução do dano e da temperatura induzida pela deformação plástica devido a carregamentos de impacto e de alta frequência, são apresentados e analisados. Comparações entre simulações com os modelos isotérmico e anisotérmico permitem caracterizar as influências da equação da energia e do dano. / [en] This work presents a mechanical model for simulating the anisothermal behavior of damageable inelastic solids under dynamical loadings. The main motivation of this study is to investigate, by means of numerical simulations, the thermomechanical coupling in a simple one-dimensional problem involving the wave propagation phenomenon in a damageable non-isothermal solid. To achieve this goal, the equation of energy is taken into account in the modeling with the coupling terms between the thermal and mechanical effects. The damageable inelastic mechanical behavior is describe by means of an internal variable constitutive theory and the analysis is restricted to elastoviscoplastic solids. The resulting system of non linear partial differential equations is solved by using an operator splitting technique, along with classical numerical procedures such as the Glimm s method. Numerical examples which illustrate the damage and temperature evolution induced by the plastic deformation process due to impact and cyclic loadings are presented and analyzed. A suitable comparative analysis between simulations with and without the thermomechanical couplings shows the situations under which these terms are relevant.

This thesis analyses consumer behaviour connected with chocolate bars. It describes metodology of marketing research. The form of the research is questionnaire. Respondents are students of VŠE. The research discovers popularity of some brands and selling places in the campus. Results are used for the formulation of recommendation for the strategy of sale.

Cellular materials are often used as impact/blast attenuators due to their capacity to absorb kinetic energy when compressed to large strains. For such applications, three key material properties are the crushing stress, plateau stress and densification strain. The difficulties associated with obtaining these mechanical properties from dynamic/impact tests are outlined. The results of an experimental investigation of the quasi-static and dynamic mechanical properties of two types of cellular materials are reported.The dynamic tests were carried out using Hopkinson pressure bars. Experimentally determined propagation coefficients are employed to represent both dispersion and attenuation effects as stress waves travel along the bars. Propagation coefficients were determined for 20 mm and 40 mm diameter viscoelastic PMMA pressure bars and for elastic Magnesium pressure bars. The use of the elementary wave theory is shown to give satisfactory results for frequencies of up to approximately 15 kHz, 8 kHz and 30 kHz for the 20 mm and 40 mm diameter PMMA bars and the 23 mm diameter Magnesium bars respectively. The use of low impedance, viscoelastic pressure bars is shown to be preferable for testing low density, low strength materials.The quasi-static and dynamic compressive properties of balsa wood, Rohacell-51WF and Rohacell-110WF foams are investigated along all three principal directions. The dynamic properties were investigated by performing Split Hopkinson Pressure Bar (SHPB) and Direct Impact (DI) tests. In general, the crushing stress, the plateau stress and the densification strain remain constant with increasing strain rate of the SHPB tests. However, a dynamic enhancement of the crushing stress and plateau stress was revealed for balsa wood and Rohacell-51WF. In contrast, the plateau stresses of the Rohacell-110WF specimens are lower for SHPB than quasi-static tests. From the DI tests, it is shown that compaction waves have negligible effect on the stresses during dynamic compaction of along and across the grain balsa wood at impact speeds between approximately 20-100 m/s. Alternatively, the proximal end stresses of both Rohacell-51WF and 110WF foams increase with increasing impact velocity, following the quadratic trend predicted by 'shock theory'. This indicates that compaction waves are important for the case of Rohacell foam, even at low impact velocities.

In the 20th century, we were witnesses an unprecedented growth of public expenditure across all the developed countries of the world. With this phenomenon was created a hypothesis about the negative impact of public expenditure on economic growth and in response to it, economists did many studies which tried to verify this negative effect. In the 80ties the first studies which confirmed the negative linear dependence of these two macroeconomic aggregates. It means greater public sector has negative impact to economic growth of countries. In the 90ties the studies which verify the nonlinear dependence of the inverted U-shaped curve with a peak where is the optimal size of public sector. This concept is collectively called "Armey curve" or "BARS curve" and my final thesis deals by this concept and my goal is to introduce BARS concept to Czech readers. It reflects the evolution of public expenditure in the 20th century and describes the theoretical and empirical development of the whole concept until now. It means a hypothesis about the positive benefits of government activities in the economy to a certain point - "optimal point" and the negative after this point. The final thesis also offers custom research on a sample of the Visegrad Four countries in years from 1995 to 2012. The aim of the research is to verify the linear dependence of growth of GDP and the share of public expenditure in GDP and the existence BARS curve and the optimal size of public spending across countries.

No description available.