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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.
1

Aerodynamics simulations of ground vehicles in unsteady crosswind

Favre, Tristan January 2011 (has links)
Ground vehicles, both on roads or on rail, are sensitive to crosswinds and the handling, travelling speeds or in some cases, safety can be affected. Full modelling of the crosswind stability of a vehicle is a demanding task as the nature of the disturbance, the wind gust, is complex and the aerodynamics, vehicle dynamics and driver reactions interact with each other.  One of the objectives of this thesis, is to assess the aerodynamic response of simplified ground vehicles under sudden strong crosswind disturbances by using an advanced turbulence model. In the aerodynamic simulations, time-dependant boundary data have been used to introduce a deterministic wind gust model into the computational domain.  This thesis covers the implementation of such gust models into Detached-Eddy Simulations (DES) and assesses the overall accuracy. Different type of grids, numerical setups and refinements are considered. Although the overall use of DES is seen suitable, further investigations can be foreseen on more challenging geometries.  Two families of vehicle models have been studied. The first one, a box-like geometry, has been used to characterize the influence of the radius of curvature and benefited from unsteady experimental data for comparison. The second one, the Windsor model, has been used to understand the impact of the different rear designs. Noticeably, the different geometries tested have exhibited strong transients in the loads that can not be represented in pure steady crosswind conditions. The static coupling between aerodynamics and vehicle dynamics simulations enhances the comparisons of the aerodynamic designs. Also, it shows that the motion of the centre of pressure with respect the locations of the centre of gravity and the neutral steer point, is of prime interest to design vehicles that are less crosswind sensitive. Recommendations on the future work on crosswind sensitivity for ground vehicles are proposed at the end of this thesis. / <p>QC 20111206</p> / crosswind stability and unsteady aerodynamics
2

Numerical Simulations on Long-Term Shoreline Changes behind Detached Breakwaters

Wu, Cheng-chung 24 May 2005 (has links)
In this thesis, a numerical simulation model is applied to investigate the long-term shoreline changes behind detached breakwaters. The model includes three components, namely a wave model, a current model, and a shoreline change model. In the numerical simulations, various combinations of wave conditions and the placement of detached breakwater are chosen to explore the effect of detached breakwaters on the shoreline change. The results of calculation show that with incident wave angles within 0~45, wave height in the range of 0.5~1.5m, or the offshore distance to the detached breakwaters being 60~120m, the larger in any one of these three parameters is, the bigger the erosion distance onshore from the original shoreline and the extent of salient offshore are behind detached breakwaters. When incident angle of the wave increases, shoreline plan form becomes skewed, and the time required to arrive at equilibrium also increases, in addition to the position of the top of salient moves downcoast. Within the wave periods of 7~10 seconds tested, waves with large period are found to show slight decrease of the erosion distance onshore and the extent of salient offshore behind detached breakwaters. The plan form of the salient is not affected by wave period. However, the larger the wave period is, the sooner the long-tern shoreline will result. Moreover, for a detached breakwater constructed in the range of offshore distances within 1.0¡ÕS/B¡Õ2.0, variable offshore distances do not produce much difference in the erosion distance onshore and the extent of salient offshore behind detached breakwaters, and salient only will form. In the case of the S/B =< 0.8, a tombolo will result. Finally, the results of shoreline plan form from the numerical modeling are verified by the empirical parabolic bay shape equation of Hsu and Evans (1989), a small-scale hydraulic model, and two numerical models based on GENESIS and LITPACK. Overall, the result are in good agreement with these four different approaches, and therefore, the present model is suitable for practical engineering applications.
3

Hotel / Hotel

Smatana, Róbert January 2019 (has links)
This diploma thesis aims to design a project documentation for a realization of a newbuild hotel. The building is in Sigord recreation ground, near Kokosovce village in Slovakia. The object is a detached building with three storeys and a partial basement. An entrance hall, offices, bar and a restaurant are situated on the ground floor. The hotel is on the first and the second floors. Foundations of the building are made of jamb blocks and a reinforced concrete beam foundation. Construction system is skeletal, consisting of concrete poles and reinforced concrete beams, filling and vertical constructions are made of Ytong aerated concrete blocks. Horizontal constructions are made from Spiroll precast panels, with reinforced concrete ceilings. The building is finished off with a single ply roof with a standard order of layers.
4

Critical possibilities: decritique, deracination, and the D.I.S.

Flores, Becky January 2005 (has links)
This dissertation presents the theory and practice of Decritique, a critical pedagogy for the first-year college English classroom that offers an alternative to contemporary applications of critical theory. Underscored by a philosophy of language drawn from Husserl's pure phenomenology and Derrida's deconstruction, a key characteristic of the pedagogy is delineation between re-cognition and recognition: the former actively seeking ways to re-position one's own thinking in relation to perceptions of the world; the latter endorsing existing perception. Concepts of "respect" and "tolerance" are questioned in Decritique, positing that they can operate as agents of oppression; instead, students engage in critical interaction and animated introspection that, in turn, opens the possibility of change. Concerned with the theory and practice of a reconceptualized critical pedagogy, the question at the core of Decritique is ways for students to reach a point of cognitive struggle leading to genuine discovery without the pain that can accompany criticism and critical self-reflection acting as a barrier to learning. Chapters One through Three examine what constitutes "the critical"; namely, critical thinking, critical pedagogy, critical literacy, and critical care, Chapter Four discusses a reconceptualization of these criticalities, Chapter Five examines the theory of Decritique, Chapter Six presents a three-semester pilot study comparing Decritique with a pedagogy of "caring" in both face-to-face and online learning environments, and Chapter Seven provides the study’s conclusions. Results indicate that students taught with Decritique consistently produced more writing than those taught with a "caring" approach, demonstrated greater evidence of "critical" reflection on essay revisions, engaged more animatedly in verbal and written discourse, exhibited a strong sense of critical camaraderie, particularly in the face-to-face classroom, and that essays averaged nearly five percent, or half a letter grade, higher. Retention and pass rates were higher in the Decritique classes and students were more likely to be satisfied with their learning experience. Implementation of the pedagogy on a wider, cross-institutional level is recommended in order to investigate the potential of Decritique as an alternative critical pedagogy for the first-year college English classroom, one that promotes reflective critical analysis of discourse with a commitment to the possibilities of praxis.
5

Improved understanding and control of high-speed jet interaction flows

Srinivasan, Ravichandra 12 April 2006 (has links)
A numerical study of the flow field generated by injection through diamondshaped orifices into a high-speed flow is presented in this document. Jet interaction flows have a wide range of applications in the field of engineering. These applications include the use of jets for fuel injection in scramjets, for reaction control of high-speed aerodynamic bodies and as cooling jets for skins of high-speed vehicles. A necessary requirement in the use of transverse jets for these and other applications is a thorough understanding of the physics of the interaction between the jet and freestream. This interaction generates numerous flow structures that include multiple shocks, vortices, recirculation regions and shear layers. This study involves diamond-shaped orifices that have the advantage of generating weaker or attached interaction shocks as compared to circular injectors. These injectors also negate the effects due to the recirculation region that is formed upstream of the injector. This study was undertaken in order to gain further understanding of the flow features generated by diamond-shaped injectors in a high-speed flow. Numerical simulations were performed using two different levels of turbulence models. Reynolds™ Averaged Navier-Stokes (RANS) simulations were performed using the GASP flow solver while Detached-Eddy Simulation (DES) runs were performed using the Cobalt flow solver. A total of fifteen diamond injector simulations were performed using the RANS model for a 15 half-angle diamond injector. The fifteen simulations spanned over five different injection angles and three jet total pressures. In addition to these, two circular injector simulations were also performed. In addition, low pressure normal injection through diamond and circular orifices simulations were performed using DES. Results obtained from CFD were compared to available experimental data. The resulting flow structure and the turbulent properties of the flow were examined in detail. The normal injection case through the diamond-shaped orifice at the lowest jet total pressure was defined as the baseline case and is presented in detail. In order to study the effect of different components of the vorticity transport equation, an in-house code was used post-process the results from the RANS runs.
6

Street violence amongst young men in London : everyday experiences of masculinity and fear in public space

Whelan, Michael January 2013 (has links)
Arising out of widespread concerns that incidents of street violence amongst young people in the UK were spiralling out of control, this research draws on feminist deconstructions of the public-private space divide to emphasise the importance of a social constructionist perspective on street violence; street violence as it is experienced, understood and constructed by young people. Methodologically this research combines ethnography with Critical Discourse Analysis in what has been referred to as critical ethnography (Fairclough, 2001). Adopting a practitioner research approach within a primarily street based youth work setting, accounts were drawn from a range of sources, including interviews and participant observation with youth workers, young people and local public figures. This study draws out the implications for young men’s subjective experiences of the inner city streets near where they live, focusing on the construction of masculinities in the context of political pressures and institutionalised discourses of young people. The young men in this research experienced uncertain and often fearful public spaces in which the ability to construct a credible propensity for violence was an essential part of a successful masculine identity. It is suggested that a significantly greater focus is required on critical gender identity work with young men, specifically in relation to their identity constructions in public space.
7

Numerical investigation of the interaction of synthetic jets with a laminar boundary layer and the effect of jet orientation

Valenzuela Calva, Fernando January 2016 (has links)
In 2009, based on its commitment to take action on the climate change, the aviation industry accorded a group of objectives to reduce carbon dioxide emissions. Although only 2% of all human-induced carbon dioxide (CO2) emissions are produced by the global aviation industry, the aviation industry is set to grow in the next 30 years. In order to maintain this growth without increasing its negative environmental impact, the future aircraft have to be cleaner and greener. In order to reduce carbon emissions and increase the operative efficiency, novel technologies have been developed and applied on aircraft. One of the recently introduced technologies is the flow control over the wing by employing active flow control methods. Amongst the active flow control methods, synthetic jets have emerged as a developing and promising technology. The latter have been extensively investigated since 1990 in laboratory based investigations. In spite of the fact that many experimental studies have been performed to design synthetic jet actuators for optimal flow control, due to the the vast number of operating parameters involved, and the lack of current measurement technologies, they can be impractical and highly expensive. Hence, there is a need for a systematic analysis to establish the optimal operating conditions with the highest effectiveness at the cost of minimum energy input, and the most suitable orientation of synthetic jet orifices. This would require enhanced comprehension of the inherent features of synthetic jets and their corresponding near wall effects. By using numerical simulations with a commercial CFD software (Star-CCM+), this thesis investigates some features associated with synthetic jet performance that are not fully understood, such as: • The optimal working configuration of a synthetic jet array embedded into a laminar detached boundary layer for flow separation control. • The effect of orifice orientation (inclined and skewed synthetic jets) over normal synthetic jets and their optimal working configuration in an attached laminar boundary layer.
8

Antracnose em feijão-fava: caracterização do agente causal e reação de genótipos a Colletotrichum truncatum

Carvalho, Eulália Maria Sousa [UNESP] 24 September 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:33:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-09-24Bitstream added on 2014-06-13T21:06:46Z : No. of bitstreams: 1 carvalho_ems_dr_jabo.pdf: 998912 bytes, checksum: fca2c550ea3f00d2dbfbc2f1213a506f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A antracnose é freqüentemente encontrada em feijão-fava na região nordeste do Brasil, porém é pouco estudada. Nesse sentido, objetivou-se caracterizar o agente causal da antracnose, determinar a reação de genótipos a Colletotrichum truncatum e investigar a viabilidade da utilização da técnica de folhas destacadas em estudos relacionados a essa doença. Isolados foram caracterizados em relação a aspectos morfoculturais quando cultivados em meios de cultura batata-dextrose-ágar (BDA) e feijão-dextrose-ágar (FDA), em temperaturas de 26, 28 e 30ºC e fotoperíodo de 12 horas. A patogenicidade dos isolados e a reação dos genótipos foram avaliadas em folhas destacadas e na planta. O comportamento dos genótipos foi avaliado em duas épocas, no período chuvoso (17 de abril a 02 de junho/2008) e período seco (13 de junho a 29 de julho/2008). O delineamento utilizado foi o inteiramente casualizado com cinco e quatro repetições para avaliação da patogenicidade e dos genótipos, respectivamente. As características morfológicas e culturais variaram de acordo com o isolado e condições de cultivo, porém, foram compatíveis com as descritas para a espécie C. truncatum. A patogenicidade foi comprovada, porém não foram detectadas diferenças significativas entre os isolados. Os primeiros sintomas da doença apareceram aos três dias após a inoculação em folhas destacadas e plantas. Os genótipos UFPI - 578, UFPI - 468 e UFPI - 26 foram suscetíveis a C. truncatum. Quando avaliados em folha destacada não diferiram estatisticamente entre si no nível de infecção, independente da época. Em planta e na ausência de chuva, UFPI - 26 apresentou o maior nível de infecção, enquanto UFPI - 578, o menor. A correlação positiva e significativa (P<0,0001) entre folha destacada e planta comprova a viabilidade do emprego da técnica de folhas destacadas em estudos relacionados a essa doença / Anthracnose is often found in lima bean plantations in the northeast region of Brazil, however, has been little studied. In this sense, the goals were to characterize the causal agent of anthracnose, determine the reaction of genotypes to Colletotrichum truncatum and investigate the viability of using the technique of detached leaves in studies related to this disease. Isolates were characterized in relation to aspects morphocultural when grown in culture BDA and FDA, in temperatures of 26, 28 and 30ºC and photoperiod of 12 hours. The pathogenicity of the isolates and the reaction of the genotypes were evaluated in detached leaf and plant. The behavior of the genotypes were evaluated in two seasons, in the presence and absence of rain. The design was completely randomized to five and four replicates to evaluate the pathogenicity and genotypes, respectively. The cultural and morphological characteristics varied according with the isolates and conditions of the grown, but were compatible with those described for the species C. truncatum. The pathogenicity was proved no significant differences between the isolates. The first symptoms of the disease appeared to three days after inoculation in detached leaves and plants. The genotypes UFPI - 578, UFPI - 468 and UFPI - 26 were susceptible to C. truncatum. When evaluated in detached leaves did not differ significantly among themselves in the level of infection, independent of the season. In plants, UFPI - 26 was the most susceptible in season 2 with the highest level of infection, while the UFPI - 578 was the least susceptible. The positive and significant correlation (P <0.0001) between detached leaves and plant prove the viability of employment of detached leaves in studies related to this disease
9

Antracnose em feijão-fava : caracterização do agente causal e reação de genótipos a Colletotrichum truncatum /

Carvalho, Eulália Maria Sousa. January 2009 (has links)
Orientadora: Maria Aparecida Pessôa da Cruz Centurion / Banca: João Carlos de Oliveira / Banca: Luiz Evaldo de Moura Pádua / Banca: Ivana Marino Bárbaro / Banca: Rita de Cássia Panizzi / Resumo: A antracnose é freqüentemente encontrada em feijão-fava na região nordeste do Brasil, porém é pouco estudada. Nesse sentido, objetivou-se caracterizar o agente causal da antracnose, determinar a reação de genótipos a Colletotrichum truncatum e investigar a viabilidade da utilização da técnica de folhas destacadas em estudos relacionados a essa doença. Isolados foram caracterizados em relação a aspectos morfoculturais quando cultivados em meios de cultura batata-dextrose-ágar (BDA) e feijão-dextrose-ágar (FDA), em temperaturas de 26, 28 e 30ºC e fotoperíodo de 12 horas. A patogenicidade dos isolados e a reação dos genótipos foram avaliadas em folhas destacadas e na planta. O comportamento dos genótipos foi avaliado em duas épocas, no período chuvoso (17 de abril a 02 de junho/2008) e período seco (13 de junho a 29 de julho/2008). O delineamento utilizado foi o inteiramente casualizado com cinco e quatro repetições para avaliação da patogenicidade e dos genótipos, respectivamente. As características morfológicas e culturais variaram de acordo com o isolado e condições de cultivo, porém, foram compatíveis com as descritas para a espécie C. truncatum. A patogenicidade foi comprovada, porém não foram detectadas diferenças significativas entre os isolados. Os primeiros sintomas da doença apareceram aos três dias após a inoculação em folhas destacadas e plantas. Os genótipos UFPI - 578, UFPI - 468 e UFPI - 26 foram suscetíveis a C. truncatum. Quando avaliados em folha destacada não diferiram estatisticamente entre si no nível de infecção, independente da época. Em planta e na ausência de chuva, UFPI - 26 apresentou o maior nível de infecção, enquanto UFPI - 578, o menor. A correlação positiva e significativa (P<0,0001) entre folha destacada e planta comprova a viabilidade do emprego da técnica de folhas destacadas em estudos relacionados a essa doença / Abstract: Anthracnose is often found in lima bean plantations in the northeast region of Brazil, however, has been little studied. In this sense, the goals were to characterize the causal agent of anthracnose, determine the reaction of genotypes to Colletotrichum truncatum and investigate the viability of using the technique of detached leaves in studies related to this disease. Isolates were characterized in relation to aspects morphocultural when grown in culture BDA and FDA, in temperatures of 26, 28 and 30ºC and photoperiod of 12 hours. The pathogenicity of the isolates and the reaction of the genotypes were evaluated in detached leaf and plant. The behavior of the genotypes were evaluated in two seasons, in the presence and absence of rain. The design was completely randomized to five and four replicates to evaluate the pathogenicity and genotypes, respectively. The cultural and morphological characteristics varied according with the isolates and conditions of the grown, but were compatible with those described for the species C. truncatum. The pathogenicity was proved no significant differences between the isolates. The first symptoms of the disease appeared to three days after inoculation in detached leaves and plants. The genotypes UFPI - 578, UFPI - 468 and UFPI - 26 were susceptible to C. truncatum. When evaluated in detached leaves did not differ significantly among themselves in the level of infection, independent of the season. In plants, UFPI - 26 was the most susceptible in season 2 with the highest level of infection, while the UFPI - 578 was the least susceptible. The positive and significant correlation (P <0.0001) between detached leaves and plant prove the viability of employment of detached leaves in studies related to this disease / Doutor
10

The detached Work Program of the Boys Club of Vancouver : an analysis of the detached work program, its initiation and progress from May 1964 - September 1967

Mclean, Alan January 1967 (has links)
The purpose of the study was: 1) To describe the similarities and differences in aims of detached work approaches between Vancouver and other major North American centres. 2) To analyze the attempted fulfillment of the goals of the detached work program of the Boys Clubs of Vancouver. 3) To suggest the formulation of data gathering tools that would provide the Boys Clubs of Vancouver with more accurate and researchable information for future inquiries. Questionnaires were formulated for: 1) The organization administrators in the areas where detached work was initiated 2) The youths with whom the detached worker made contact. 3) Data was provided by the Boys Club describing the pre- and post-orientation program which they offered to their line detached workers. A third set of data regarding line worker perceptions of their training and role was obtained by us in February 1967 using the same tool as the. Boys Club for their documentation. We used the above data tools to attempt to determine the following: 1) The influence of the detached worker on delinquency rates, family situations educational factors, peer group and.authority relationships and leisure time activities. 2) The amount of neighbourhood organization involvement in the detached work program. 3) The workers perception of their role and any discrepancies from the prescribed role formulated by the sponsoring agency. Provisional findings are as follows: 1) More youths increased their delinquent activities than decreased their delin- quent activities while associating with the detached worker. 2) No work was done with the families of the involved teens. 3) Patterns of leisure-time activities were significantly influenced by the detached worker's presence. 4) The number of referrals that agencies stated they wanted from the detached work program was significantly higher (50% yes 25% no) than actually handled (6% yes 75% no). There was a similar trend in the number of referrals wanted and handled by the detached work program (36% wanted referrals 19% actual referrals). 5) 50% of the organizations contacted stated they could take a more active role in the detached work program largely in the area of use of facilities. 6) Observations and conclusions in the area of the workers' perception of his role (#3 page 2) were totally subjective and largely without statistical reliability. / Arts, Faculty of / Social Work, School of / Graduate

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