No description available.

The present work addresses the fundamental question involving the modeling of subgrid-scale turbulence as a function of resolved field. A new-nonlinear model has been developed from the constitutive equation of subgrid stresses extending the Reynolds stress model proposed by Warsi. The time scale is expressed in terms of subgrid scale kinetic energy as opposed to strain rate tensor. Effort has been made to identify the terms appearing in the modeled subgrid stresses with "Reynolds term", "Leonard's term" and "cross term". The physical nature of these terms can be best understood from the triadic interactions in wave number space. Understanding these three terms leads to decouple the complex nature of the subgrid stresses. Modeling of these terms separately helps to capture the physics of the problem accurately. The turbulent field is assumed to be isotropic and Kolmogrov's hypothesis is used. The model coefficients are expressed as universal constants for Gaussian filter so as to satisfy the dissipation criteria in inertial subrange. Further dissipation term is assumed to be isotropic and equilibrium condition is used. Although the definition of the subgrid stress terms becomes less clear and separate for smooth filter, an attempt has been made to compare the stress terms with the exact definition obtained for sharp cut-off filter. An estimate of the backscatter of energy can be obtained from the Eddy-Damped Quasi Normal Markovian (EDQNM) theory. The model coefficients thus obtained are tested with results of plain homogeneous shear layer. The model results have been compared with the mixed-nonlinear model and Smagorinsky model. A priori test shows that new-nonlinear model has a good correlation with Smagorinsky model, which in turn has good correlation with experimental results, and has the behavior of the mixed-nonlinear model. The above model has been used for solving two-dimensional flow over backward facing step as a test case. The numerical model solves the vertically hydrostatic boundary layer equation. The top boundary is assumed to be a free surface. Terrain following coordinate system has been used. Because of the non-negativity of the subgrid scale dissipation term i.e. backscatter of energy, the nature of the solution is stochastic. The deterministic solution is obtained by clipping the dissipation term. The results are compared with the experimental data of Kim et al. Good agreement with the experimental data is obtained for the velocity profile and SGS kinetic energy. The reattachment point obtained is at 5.2h (h is the step height), which is less compared to 6h as suggested by other authors. This discrepancy may be due to the assumptions involved in the equations, which is being solved. The model is further extended for the diffusion of scalar variables and to include the buoyancy effect. It is implemented to explore the hydrostatic flow over three dimensional elliptical mountain ridges, where Boussinesq approximation is used for variable density. The flow characteristics have been studied for the various aspect ratios of the mountain and Froude?s number (Nh/U) based on Brunt-Vaisala frequency (N). The phenomenon of upstream blocking and Lee-vortices generation has been studied.

Made available in DSpace on 2016-07-27T14:20:17Z (GMT). No. of bitstreams: 1 Gelcimary Menegatti da Silva.pdf: 713014 bytes, checksum: aac0a1dc8ac09ff2b11ede59ff1df1d0 (MD5) Previous issue date: 2014-02-28 / Violence, understood as the detrimental act of violating social rules to the extent of harming others, is present in our everyday lives. The subjects are affected by the violence present indirectly in the news which is heard, seen or read in the different means of communication, as well as present as witnesses of situations of external violence, and directly as in an episode in which they become victims. Currently, a number of researches have been carried out with the aim of investigating the impact of varied forms of violence such as negligence, sexual abuse and physical violence. However, a specific study can overestimate the consequences of only one type of violence and underestimate the influence of other forms. In the studies performed since 2005 using the Juvenile Victimization Questionnaire (JVQ), whose objective is to map the quantity and co-occurrence of the victimizations, it was observed that polyvictim subjects, i.e., those who suffered four or more forms of violence in the previous year, presented worse levels of mental health, higher chances of being victims again or practicing violence, academic difficulties and higher vulnerability to adversities. Nevertheless, it is observed that some people, faced with difficult moments in their lives as the experience of violence, manage to continue their lives healthily, which can be due to the form of facing or coping used to manage the problem or the emotion coming from the source of stress. Research correlates positively the predominant use of coping focused on the problem to better levels of mental health. The teaching of these strategies can occur through varied ways, such as a cognitive-behavioral approach to psychotherapy. Therefore, this paper has as aim to analyze, based on theories of poly-victimization, coping and cognitive-behavioral approach, two clinic cases. The first one refers to a 31-year-old woman and the second, a child aged 3, both with experience of several episodes of violence. The sessions were divided in initial evaluation and intervention in the first case, and in initial evaluation, intervention and final evaluation in the second. According to the demand, in the psychotherapeutic intervention, Beck s cognitive therapy (1964) was used on the adult patient and analytical behavioral therapy on the juvenile patient. The results indicated better levels of mental health, higher frequency of usage of better adapted strategies, as those focused on the problem, and interruption of the victimization cycle. / A violência, entendida como o ato prejudicial de violar as regras sociais a ponto de prejudicar o próximo, está presente no nosso cotidiano. Os sujeitos são afetados pela violência presente indiretamente como nas notícias ouvidas, assistidas ou lidas por meio dos mais diferentes meios de comunicação, assim como presentes enquanto testemunhas de situações de violência externa, como também de maneira direta como num episódio em que se torna a vítima. Atualmente, muitas pesquisas têm surgido com o intuito de investigar o impacto das diversas formas de violência como a negligência, abuso sexual e violência física. No entanto, o estudo específico pode superestimar as consequências de apenas um tipo e subestimar a influência das outras formas de violência. Nos estudos realizados desde 2005 utilizando o Juvenile Victimization Questionnaire (JVQ) cujo objetivo é mapear a quantidade e co-ocorrências das vitimizações foram observados que os sujeito polivítimas, ou seja, aqueles que sofreram quatro ou mais formas de violência no ano anterior, apresentaram piores níveis de saúde mental, maiores chances de novamente serem vítimas ou praticar violência, dificuldades acadêmicas e maior vulnerabilidade as adversidades. No entanto, observa-se que algumas pessoas diante da vivência de momentos difíceis na vida como a experiência da violência, conseguem seguir suas vidas saudavelmente o que pode ser devido à forma de enfrentamento ou coping utilizadas para administrar o problema ou a emoção advindo da fonte estressora. Pesquisas correlacionam positivamente o uso predominante de coping focado no problema a melhores níveis de saúde mental. O ensino destas estratégias pode ocorrer por diversos meios como a psicoterapia de abordagem cognitivo-comportamental. Diante disso, este trabalho teve como objetivo analisar com base nas teorias de polivitimização, coping e abordagem cognitivo-comportamental dois casos clínicos. O primeiro se refere a uma mulher com 31 anos de idade e o segundo, uma criança com 3 anos de idade, ambos com experiência de vários episódios de violência. As sessões foram divididas em avaliação inicial e intervenção para o primeiro caso e avaliação inicial, intervenção e avaliação final para o segundo. De acordo com a demanda, utilizou-se na intervenção psicoterapêutica, a terapia cognitiva de Beck (1964) para a paciente adulta e terapia analítico-comportamental para o paciente infantil. Os resultados apontam melhores níveis de saúde mental, mais frequência do uso de estratégias mais adaptadas como as focadas no problema e quebra do ciclo de vitimizações.

O uso de sistemas de faceamento flexíveis com malhas metálicas é uma alternativa viável ao uso do concreto projetado como faceamento em sistemas de solo grampeado. Vários modelos de malhas são empregados hoje para este uso, sendo classificados pela resistência à tração no sentido longitudinal. Mesmo que relevante, segundo Cala et al., (2012), somente este dado é insuficiente para o correto dimensionamento destas soluções. A presente pesquisa busca identificar quais os parâmetros de resistência são necessários para o dimensionamento de um faceamento em malha metálica. Para tanto foram avaliadas duas metodologias desenvolvidas especificamente para as malhas aplicadas junto com a solução de solo grampeado, os métodos Ruvolum e Macro1. Foram então desenvolvidos equipamentos, similares aos utilizados por Roduner (2011) e Cala et al. (2012), para caracterizar 4 diferentes modelos de malhas, avaliando a resistência das mesmas frente aos esforços considerados nos modelos de cálculo investigados, tração e o cisalhamento no contato malha/grampo. Deste modo, foram utilizados resultados de ensaios em escala real com a simulação de um talude em solo tratado com as 4 malhas, para a validação dos métodos de dimensionamento, e para investigar quais os parâmetros de resistência da malha são mais importantes. Como resultado foram determinadas as resistências das malhas avaliadas, sendo a de tração no sentido longitudinal entre 50 e 140 kN, e a resistência no contato malha/grampo, que variou entre 10 e 30 kN. Por fim foi realizada uma análise paramétrica com o método Ruvolum a fim de verificar a influência na variação da coesão, espessura instável e ângulo de atrito, dados nem sempre bem definidos em projeto. Os resultados mostram, como era esperado, a grande sensibilidade da variação nos resultados frente aos efeitos da coesão, sendo então recomendado, como em qualquer análise de estabilidade cautela no uso deste parâmetro. A análise destes resultados permite concluir que o método mais adequado para modelar um talude em solo grampeado com face em tela foi o Ruvolum, com previsões que se aproximaram das medições reais dos ensaios de campo. / The use of flexible facing systems with steel meshes is a viable alternative to the use of shotcrete as facing in soil nailing systems. Currently several different models meshes are being used today for this purpose, being classified only by the tensile strength in the longitudinal direction of the mesh. Even though this parameter is quite relevant, alone it cannot be used to design the flexible facing systems. So this research aims to identify which steel mesh strength parameters are really needed for the correct dimensioning of such solutions. In order to do so two calculation methodologies, specially developed for steel meshes design, were investigated. The design models are called Ruvolum and Macro1 Equipments were developed, similar to those presented in Cala et al. (2012), to investigate four different models of mesh, in order to find the strength parameters presented on the studied calculation models, being than tensile and shear. Thus, to validate the investigated design methodologies, field tests results were compared to the models predictions. As product of the research it was possible to determine the tensile strength of the 4 meshes models, being then ranging from 50 and 140 kN. Also it was possible to define the shear resistance in the nail head/mesh contact, which ranges from 10 to 30 kN. The last step of the research was a parametric analysis, performed with the Ruvolum method to evaluate the influence on the variation of cohesion, unstable thickness and friction angle in the predictions, since this data aren’t always available in ordinary projects. These analysis have showed that the most influent parameter is cohesion, one that is very hard to determine. Also it was found by the results analysis that the appropriate calculation model to simulate a slope stabilized with soil nail and steel meshes facing is the Ruvolum, due the closeness of the predictions to the real field data.

O torneamento radial é um processo de usinagem usado na indústria metal mecânica para o corte de peças, abertura de canais ou faceamento. Esta pode ser considerada uma operação crítica devido à forma geométrica da ferramenta e aos movimentos de corte. Isto gera a necessidade de aplicação de fluidos de corte, normalmente em abundância, na região de corte. Considerando como funções destes fluidos o arrefecimento, a lubrificação e a expulsão do cavaco, sua aplicação durante essa operação é de suma importância. Várias pesquisas visam restringir o uso de tais fluidos, seja por critérios econômicos, ambientais ou sanitários. Neste contexto, o uso da técnica de mínima quantidade de lubrificante (MQL) vem ganhando espaço nos meios produtivos. Embora seja aplicada há anos em diferentes processos de usinagem, existem poucos relatos sobre a aplicação de MQL em operações de torneamento radial; no mesmo seguimento, a aplicação de ar comprimido (ACO) vai ao encontro do conceito de usinagem ambientalmente amigável. Assim, este trabalho apresenta uma análise comparativa na aplicação de lubrificantes em abundância (ABD), em MQL e o uso de ACO no torneamento radial do aço SAE 1045 para diferentes condições de corte. Na investigação, foram consideradas as forças geradas durante o processo, as rugosidades e o desvio dimensional das superfícies usinadas, e o desgaste da ferramenta. Observou-se que os esforços gerados com MQL foram similares ou inferiores aos gerados com ABD. A mesma tendência foi observada no perfil de rugosidade, predominando valores inferiores. O MQL possibilita um corte mais estável durante a vida da ferramenta, reduzindo a ocorrência de desgaste e prolongando sua vida útil, minimiza a oscilação axial e a flexão da ferramenta, reduz as rugosidades e minimiza os desvios dimensionais. Assim, pode-se afirmar que a aplicação da técnica por MQL é viável no torneamento radial do aço SAE 1045. / Radial turning is a machining process used in the metalworking industry for parting off, grooving or facing operations. This can be considered a critical operation due to the geometric shape of the tool and the cutting movements. This generates the need for application of cutting fluids, usually in abundance, in the cutting region. Considering as functions of these fluids the cooling, lubrication and expulsion of the chip, their application during this operation is of paramount importance. Several researches aim to restrict the use of such fluids, either by economic, environmental or sanitary criteria. In this context, the use of the minimum quantity of lubricant (MQL) technique has been gaining ground in the productive media. Although it has been applied for years in different machining processes, there are few reports on the application of MQL in radial turning operations; at the same time, the application of compressed air (ACO) meets the concept of environmentally friendly machining. Thus, this work presents a comparative analysis on the application of abundant lubricants (ABD) in MQL and the use of ACO in radial turning of SAE 1045 steel for different cutting conditions. In the investigation, the forces generated during the process, the roughness and the dimensional deviation of the machined surfaces and the tool wear were considered. It was observed that the machining forces generated with MQL were similar or inferior to those generated with ABD. The same tendency was observed in the profile of roughness, predominating lower values. MQL enables a more stable cut during tool life, reducing the occurrence of wear and extending tool life, minimizes axial oscillation and tool flexion, reduces roughness and minimizes dimensional deviations. Thus, it can be indicated that the application of the technique by MQL is feasible in the radial turning of SAE 1045 steel.

The service sector’s constant growth is followed by an increasing competition among service companies. Followed by this, the process of internal branding has become essential within the service brand building process, i.e. aligning the service company’s brand promise with employees’ behavior. Hence, customer- facing employees within the service organization have become a valuable and competitive asset as they manage to deliver the brand promise. A literature review showed that understanding the brand promise and brand commitment are two essential drivers of internal branding. An implicit and positive relationship between those two issues was presented. Absence of empirical studies regarding this relationship was revealed. The purpose of this thesis is to investigate the relationship between employees’ understanding of the brand and their brand commitment. The purpose motivated a hypothesis; employees understanding of the brand promise are positively associated with their brand commitment. The results are based on a quantitative survey conducted among customer- facing employees within the Swedish bank industry. The analysis is both founded in the discussion of the conceptual literature and the similar completed empirical study that was found within the research area. The findings of this research supported this thesis’ hypothesis. The relationship between bank customer- facing employees’ understanding of the brand promise and their brand commitment is shown to be positive and fairly strong. Almost two fifths of brand commitment can be explained by the understanding issue. However, it shows a need for further research in identifying more factors influencing employees’ commitment towards the brand.

The effect of direct, small-scale excitation on the evolution of a plane shear layer which forms at the edge of a backward facing step is investigated experimentally using high resolution particle image velocimetry and hot-wire anemometry. Actuation is effected at frequencies that are over an order of magnitude higher than the characteristic (or natural) formation frequency of the layer by a spanwise array of piezoelectrically-driven synthetic jet actuators that are placed near the edge of the step. The actuation has significant effects on the evolution of both large- and small-scale motions within the shear layer inducing an increase in small-scale dissipation and simultaneous suppression of turbulence production. While the fundamental instabilities that lead to the formation of large scale motions are typically suppressed, low-frequency amplitude-modulation of the actuation signal allows the formation of large scale motions and entrainment which, in concert with the small-scale actuation, lead to enhancement of the turbulent shear stresses throughout the shear layer. Amplitude modulation is also used to assess the effect of flow transients that are induced by step or low duty cycle actuation. The present findings suggest strategies for controlled suppression or enhancement of mixing in the near field of the shear layer.

No description available.

An experimental research was performed to study the effects of surface roughness on the characteristics of separated and reattached turbulent flows in an open channel. A backward facing step was used to induce flow separation. The rough surfaces comprised wire mesh grit-80 and sand grains of average diameter 1.5 mm. In each experiment, the Reynolds number based on the step height and freestream velocity of approach flow was fixed at 3240 and the Reynolds number based on the approach flow depth and freestream velocity was kept constant at 25130. Particle image velocimetry (PIV) technique was used to measure the flow velocity. The results showed that roughness effects on the mean and turbulent quantities are evident only in the recovery region. Moreover, roughness effects on the flow dynamics are dependent on the specific roughness element.

An experimental research was performed to study the effects of surface roughness on the characteristics of separated and reattached turbulent flows in an open channel. A backward facing step was used to induce flow separation. The rough surfaces comprised wire mesh grit-80 and sand grains of average diameter 1.5 mm. In each experiment, the Reynolds number based on the step height and freestream velocity of approach flow was fixed at 3240 and the Reynolds number based on the approach flow depth and freestream velocity was kept constant at 25130. Particle image velocimetry (PIV) technique was used to measure the flow velocity. The results showed that roughness effects on the mean and turbulent quantities are evident only in the recovery region. Moreover, roughness effects on the flow dynamics are dependent on the specific roughness element.