In recent times, high power density trends and temperature constraints in integrated circuits have led to conventional cooling techniques not being sufficient to meet the thermal requirements. The ever-increasing desire to overcome this problem has led to worldwide interest in micro heat sink design of electronic components. It has been found that geometric configurations of micro heat sinks play a vital role in heat transfer performance. Therefore, an effective means of optimally designing these heat sinks is required. Experimentation has extensively been used in the past to understand the behaviour of these heat extraction devices. Computational fluid dynamics (CFD) has more recently provided a more cost-effective and less time-consuming means of achieving the same objective. However, in order to achieve optimal designs of micro heat sinks using CFD, the designer has to be well experienced and carry out a number of trial-and-error simulations. Unfortunately, this will still not always guarantee an accurate optimal design. In this dissertation, a design methodology which combines CFD with a mathematical optimisation algorithm (a leapfrog optimisation program and DYNAMIC-Q algorithm) is proposed. This automated process is applied to three design cases. In the first design case, the peak wall temperature of a microchannel embedded in a highly conductive solid is minimised. The second case involves the optimisation of a double row micropin-fin heat sink. In this case, the objective is to maximise the total rate of heat transfer with the effect of the thermal conductivity also being investigated. The third case extends the micropin-fin optimisation to a heat sink with three rows. In all three cases, fixed volume constraint and manufacturing restraints are enforced to ensure industrial applicability. Lastly, the trends of the three cases are compared. It is concluded that optimal design can be achieved with a combination of CFD and mathematical optimisation. / Dissertation (MEng)--University of Pretoria, 2011. / Mechanical and Aeronautical Engineering / Unrestricted

The demand for smaller but more powerful electronic components is ever increasing. This demand puts a strain on engineers to produce optimal cooling designs for these electronic components. One method for cooling these electronic components is with heat sinks which effectively increase the surface area available for extracting the heat from the electronic components. Computational Fluid Dynamics (CFD) software is sometimes used to aid in the design process, but CFD simulations are computationally expensive and take long to complete. This causes the design engineer to test only a few proposed designs based on his/her experience and select the design that performs the best out of the tested designs, which might not be the optimum. The temperature distribution inside the heat sink can be solved relatively quickly with the diffusion equation, but the flow around the heat sink complicates the CFD simulation and increases the solving time significantly. Therefore, applications have been developed where the interaction between the heat sink and the flow around the heat sink is replaced by heat transfer coefficients. These coefficients are calculated from correlated equations which contain the flow properties. The flow properties are extracted from a flow network solver, which solves the flow around the heat sink. This procedure results in less expensive simulations, which can be used together with an optimisation procedure to develop an optimum cooling design. In this dissertation, a correlation for the contraction heat transfer coefficients of rectangular pin fin heat sinks was developed. A methodology was developed where consecutive regression lines were fitted to a large set of data extracted from numerous CFD simulations. The combination of these regression lines formed the basis of the correlation, which was divided into two correlations; one for laminar flow and another for turbulent flow. The correlations were tested against CFD simulations as well as experimental data. The results indicate that these correlations can be effectively used to calculate the contraction heat transfer coefficients on pin fin heat sinks. / Dissertation (MEng)--University of Pretoria, 2011. / Mechanical and Aeronautical Engineering / unrestricted

abstract: This study examines determinants of the length of conflict between firms and the Internal Revenue Service (IRS). I hand collect firm disclosures of the number of years open for federal tax purposes to create a proxy for IRS conflict length. Using this proxy, I find evidence that larger firms, firms with more book-tax differences, and firms facing higher IRS attention and audit probabilities are associated with lengthier IRS conflicts. In contrast, firms with higher deferred tax assets, intangibles, return on assets, and firms disclosing participation in the Compliance Assurance Process program are associated with shorter IRS conflicts. Additional analyses show IRS conflict length is positively associated with manager risk preferences and poor tax accounting quality. I also find lengthier IRS conflicts are associated with higher future tax risk and higher audit fees. Tax controversy is becoming increasingly important for firms but remains relatively understudied. I provide empirical evidence on cross-sectional variation in IRS conflict length. / Dissertation/Thesis / Doctoral Dissertation Accountancy 2020

This diploma thesis deals with project of shaft manufacturing using drop forging technology. This technology is manufacturing using cubic forming on vertical forging press. Work includes detail data for working out technical drawings of suggested component. Thanks to modification of parameters and forging a whole we reduce material waste which is compared to turning technology. Production process is adapted to established production process in company Kovarna ZETOR Brno. Further the work includes cost price of one forging from the set of 30 000 products a year. The work also contains background research of drop forging technology, technical drawings, production process list and simulation outcome for drop forging of the suggested komponent by software FormFEM.

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Syftet med den här uppsatsen är att undersöka clownens betydelser i konstnären och regissören Alejandro Jodorowskys psykomagiska autobiografi Poesía sin fin (2016). Uppsatsen önskar även vidga förståelsen av hur filmmediet kan användas som verktyg för att bearbeta emotionella skador och trauman. Filmmediet inrymmer möjligheter att skapa bilder som kan beröra oss på många olika plan. Jodorowsky använder mediet specifikt för att skapa psykomagiska akter, akter som skapar möjlighet för läkning. De två karaktärer som Jodorowskys egen person pendlar mellan i sin autobiografi Poesía sin fin är poeten och clownen. Clownen kommer här att undersökas då han står i tydlig kontrast mot den poet som är Jodorowskys vardagliga alter ego i resten av filmen. Genom ett analysera två scener i Poesía sin fin kommer jag besvara frågorna:Vad representerar clownen i scenerna ”Mötet med Zanahoria” och ”Cirkus”?På vilka sätt bidrar clownfiguren till Jodorowskys läkningsprocess?

<p>Heat sinks have the capability of increasing operating heat flux limits for improved thermal management in the immersion cooling of electronics using dielectric fluids. However, even for arrays of simple, straight fins, the generation of vapor between and along fins during pool boiling lead to performance effects that are not well understood. Further investigation of the heat-flux-dependent variation of boiling modes that can manifest along the fin height is required. Although methods for the prediction of fin boiling heat transfer exist that incorporate a variable heat transfer coefficient determined from a flat surface, they have been developed and assessed for single, isolated fins under the assumption that the sides of the fin at any location behave like that of a flat surface. As a result, when applied to fin arrays, these methods may not always be accurate for the full range of heat flux operation along boiling curve up to the critical heat flux, due to the fins interfering with each other when arranged in arrays of differing spacing and height. To establish when the fins in an array can be described as isolated and having the flat surface boiling behavior, pool boiling experiments are performed using copper heat sinks in two fluids with vastly different properties: HFE-7100 and water. The spacing and height of the longitudinal fins are varied across a range from much larger to less than half of the scale of the capillary length scale of both fluids, <em>L</em>_<em>b</em>. High-speed visualizations enable the identification of different boiling regimes to identify correspondence between flow observations and the boiling performance, such as when there is bubble confinement from fin interference. Trends in the pool boiling data are also compared, noting changes in superheat at various heat fluxes to establish when fin height or spacing affects boiling behavior. The experimental boiling performance is compared to predictions developed assuming isolated fins so as to identify the spacings and heights for which the fin arrays follow this behavior. Overall, the data from both fluids strongly support a hypothesis that <em>L</em>_<em>b</em> is the key length scale. Heat transfer from fin array heat sinks with heights and spacings above <em>L</em>_<em>b</em> are shown to be accurately predicted in both fluids. However, spacings smaller than <em>L</em>_<em>b</em> lead to bubble confinement which affects the superheat, particularly at low heat fluxes, while heights shorter than <em>L</em>_<em>b</em> are unable to support multiple boiling regimes along the fin sidewall. This work identifies the capillary length as the key length scale at which confinement and height effects need to be considered for accurate predictions of immersion cooling applications.</p>

Introducción: El cumplimiento de los principios éticos en investigación es necesario para un adecuado desarrollo de la investigación. No se han encontrado estudios que evalúen el cumplimiento de dichos principios en tesis de pregrado de medicina. Objetivo: Determinar el cumplimiento de los principios éticos en investigación en las tesis de pregrado de los médicos colegiados en el año 2018 en la región Lambayeque y evaluar su relación con las características del estudio, la universidad y del asesor. Materiales y Métodos: Estudio descriptivo transversal con análisis exploratorio. Muestreo tipo censal. Se evaluaron 78 tesis de pregrado y se determinó el cumplimiento de los principios éticos en investigación a través de una adaptación del instrumento desarrollado en la Universidad “La Salle” según juicio de expertos. Se evaluaron el tipo de estudio, características del asesor y de la universidad. Resultados: La frecuencia de cumplimiento fue: la metodología adecuada en 62,8%, el principio de autonomía en 30,8%, beneficencia en 63,8%, no maleficencia en ninguno de las tesis y el de justicia en 71,8%. La metodología rigurosa estuvo asociada a las tesis de universidades privadas (p=0,003) y los estudios descriptivos (p<0,001); el principio de autonomía a las universidades privadas (p=0,006) y a la aprobación por un comité de ética en investigación (p=0,027) y el principio de beneficencia a las universidades privadas (p=0,006). Conclusión: El cumplimiento de los principios éticos en investigación fue variable. Las tesis realizadas en universidades privadas, los estudios descriptivos y la aprobación por un comité de ética estuvieron asociados al cumplimiento de estos principios.

Harold Frederic's The Damnation of Theron Ware (1896) is an important work of American fiction that deserves greater critical attention. My intention in creating a website devoted to Frederic's masterpiece is not only to promote awareness of the novel but also to provide high school and undergraduate students, as well as their teachers, with a resource that will situate The Damnation of Theron Ware within an historical as well as a literary and cultural context. Significant events and discoveries in the fields of science, technology, religion, philosophy, art, and literature shaped Frederic's thinking and writing, particularly the events and characters of The Damnation of Theron Ware. An understanding of this milieu is critical to understanding the issues of the richly complicated novel. The Damnation of Theron Ware, or Illumination as it is known in England, is the story of a Methodist minister who loses his faith when he makes the acquaintance of a Catholic priest, a post-Darwinian scientist, a New Woman, and a pragmatic con artist. In the end, critics are in disagreement as to the extent of Theron's damnation or illumination. A best seller in the 1890s, The Damnation of Theron Ware was heralded as both "the great American novel" and as "anti-American" in its sentiments. Conceived as an ongoing project and research tool, my thesis is an online study guide with annotated bibliography of criticism devoted specifically to The Damnation of Theron Ware. The website is divided into six main sections: (1) the home page, which briefly introduces users to the site, identifies the scope of the project and provides links to other pages; (2) "Harold Frederic," which includes a biography of the author, a timeline of significant events during his lifetime, a select bibliography of his writing, and a sampling of interviews with and articles on Frederic as author and critic; (3) "Bibliographical Studies," which lists bibliographies, checklists, catalogues, critical overviews, and online resources; (4) "The Damnation of Theron Ware," which includes a discussion of the contemporaneous critical reception of the novel, an annotated bibliography of criticism in list form and broken down by subject, a bibliography of dissertations and theses, and recommended discussion questions or topics for essays; (5) a "Glossary," which includes terms that may be unfamiliar to students; and (6) "Links of Interest," which directs users to other websites relevant to a study of The Damnation of Theron Ware.