This thesis was performed at Scania CV AB and aimed to optimize the effect of shot peening in order to increase the bending fatigue limit of planetary gears. In this project three parameters affecting the performance of the shot peening were examined in more detail, specifically the hardness of the shot peening media, the hardness of the material and the amount retained austenite. Shot peening and measurements were performed on carburized gears consisting of ss 92506 steel. In order to find out how the fatigue limit is affected by the material hardness, a number of gears were tempered whereas other remained untempered. Similarly the retained austenite content was altered in some of the gears with a cryotreatment. The shot peening of these gears was performed by dual shot peening using media of two different hardness. The fatigue limit was evaluated by a servo hydraulic material testing machine. The results show that the fatigue limit is enhanced when the shot peening was performed with hard media. This was expected since the harder media can cause larger plastic deformation in the material giving rise to larger compressive residual stresses which is known to increase the fatigue limit. The fatigue limit was also improved for samples with lower surface hardness. The amount of retained austenite does not seem to affect the fatigue limit for samples shot peened with media of sufficient hardness in order to cause adequate plastic deformation. The surface roughness remained unchanged for samples shot peened by different media, which indicates that this parameter should not hinder a change of media.

The objective of this thesis is to explore how human beings manipulate their dexterous operation skills to produce follow shot, stop shot, and draw shot while playing billiard. According to basic mechanics, the forces exerted on a billiard ball are analyzed in three different conditions. They include the cue stick hitting the cue ball, collision between the cue ball and the object ball, and the interaction between the ball and the surface. Mathematical models for those three fundamental techniques: the follow shot, the stop shot, and the draw shot, are developed by incorporating the rolling resistance. The friction between the surface and the ball, and the dent on the surface due to the mass of the ball are considered. Furthermore, reverse derivations are also implemented to solve initial hitting conditions between the cue stick and the cue ball for certain final states for the cue ball and the object ball. Computer simulations in virtual reality are conducted using the 3D Studio Max 8 software tool. Opinions from billiard experts are also collected for the purpose of verification. Based on simulation results, reversed derivation can accurately predict final states of the cue ball and the object ball for both stop shot and draw shot. However, for the case of follow shots, final position of the object ball cannot be fully determined. Besides, no unique solution exists for the hitting condition in all three types of shot.

No description available.

Dans ce travail de recherche, on présente des développements spécifiques de diagnostiques optiques et leur application à l’étude aéroacoustique des jets rapides à haut nombre de Reynolds. Les résultats expérimentaux présentés ici résultent de visualisation par strioscopie et, de manière prépondérante dans ce manuscrit, de mesure de masse volumique par diffusion Rayleigh. Ces méthodes de caractérisation d’écoulement, appliquées aux jets subsoniques ou supersoniques, ont été associées à des mesures de bruit en champ lointain. La mesure par diffusion Rayleigh, qui repose sur la lumière diffusée par les molécules constituantes du gaz, et n’est donc pas intrusive. Des difficultés apparaissent néanmoins pour exploiter les résultats lorsque le milieu diffusant contient des poussières. Bien que l’air des écoulements obtenu en soufflerie soit filtré, la quantité résiduelle de poussières a rendu nécessaire le développement d’une méthode de nettoyage du signal en post-traitement. Le niveau des signaux obtenus par diffusion Rayleigh est très faible, et dominé par du bruit appelé shot noise. Un gain significatif sur le niveau de ce bruit a été obtenu en optimisant la chaîne d’acquisition après analyse des systèmes existants. De plus une méthode de traitement du signal dérivée d’une méthode existante a permis de calculer des spectres de masse volumique malgré le shot noise avec un seul capteur, là où il en fallait deux auparavant. Les profils de p obtenus par cette technique ont montré qu’il existe une loi de similarité permettant de superposer les profils mesurés à différentes positions axiales. Cette loi est identique pour les jets issus de trois tuyères aux géométries différentes, et à des nombres de Mach de 0.7 et 0.9. Une loi de similarité est également observée pour p’rms si les profils sont mesurés suffisamment loin de la tuyère. L’étude des spectres dans la couche de mélange a mis en évidence un maximum faiblement marqué autour d’une fréquence centrale comprise entre St = 0:2 et St = 2 dans les régions mesurées, plus marqué que dans les spectres de vitesse, et dont le comportement diffère selon l’état initialement laminaire ou turbulent du jet. L’évolution de la forme des spectres en fonction de la différence de masse volumique entre le jet et le milieu ambiant, ainsi qu’en fonction du nombre de Mach, a également été étudiée. Une loi permettant de superposer les spectres a été définie empiriquement sur la plage de variation des différents paramètres. Des mesures simultanées entre l’acoustique en champ lointain et la masse volumique dans l’écoulement ont été réalisées pour un jet à Mj = 0:9 et un jet à Mj = 1:32. Ces résultats ont permis l’estimation de cohérences spectrales et de moyennes conditionnelles. Les résultats obtenus mettent en évidence la présence de structures liées au rayonnement acoustique dans une région située proche de l’axe du jet en aval du cône potentiel. Pour finir, une étude a été réalisée sur le screech dans les jets supersoniques sous-détendus. Elle a permis d’identifier la position de la source de la rétroaction acoustique pour les modes A1, A2, et B, ainsi que la structure du cycle de la boucle qui détermine les changements de fréquences observés aux sauts de modes. / In this research study, developments of optical diagnosis techniques are presented, and are put into practice in an aeroacoustics study of high speed and high Reynolds jets. The results described here are obtained from Schlieren visualization, and in the majority from density measurements through Rayleigh scattering. These measurement methods are applied for subsonic and supersonic jets, and associated with far field acoustics measurements. Rayleigh scattering measurements rely on laser light scattered by the molecules constituting the flow, thus they are non-intrusive. However, some difficulties in interpreting the results arise when the flow contains dust particles. This problem is partly solved by using air filters in the wind tunnel, but some residual dust particles remain, thus a software based signal cleaning method has been developed and is applied to the signals during post-processing. Besides, the signals obtained from Rayleigh scattering are very weak, and dominated by a shot noise. The noise level has been significantly reduced following the optimization of the chain of acquisition in comparison with actual apparatus. Moreover, a method to compute spectra despite the shot noise level has been adapted from a classic method to be usable with a single sensor instead of two. The analysis of radial profiles of density measured with the Rayleigh scattering apparatus shows that a similarity law allows to superimpose radial profiles measured in jets exhausted from three different nozzles at Mach 0.9 and Mach 0.7. Another similarity law is observed for radial profiles of 0 rms when they are measured far enough form the nozzle. The analysis of density spectra in the mixing layer points out the presence of a local maximum of central frequency found between St = 0:2 and St = 2 depending on the probed location, which is not as clearly observed in velocity spectra. The spatial evolution of this maximum is found different whether the flow is initially laminar or turbulent at the nozzle exit. The dependence of spectra to the Mach number, and to the difference of density between the jet and the surrounding is also studied. A scaling law is empirically determined for the scope of the study. Simultaneous measurements of density and farfield acoustic acquired in a Mach 0.9, and a supersonic ideally expanded Mach 1.32 jets are processed to obtain coherence, and conditional averaging. The results emphasis the role of large structures downstream the end of the potential core in acoustic radiations. Finally, the screech in underexpended jets is studied. This work results in the identification of the acoustic feedback source location for A1, A2 and B modes, and in the characterization of the changes in the loop structure associated with mode switching.

Visual storytelling has come a long way since primitive man began creating colorful, narrative cave paintings. In this new age of technology, motion pictures have become a prevalent medium for visual storytelling throughout the developed world. Filmmakers have the added advantage of being able to create more and more fantastic settings and stories with the introduction of computer generation images (CGI). They also gain a fine degree of control over the visual elements of the final product. The ultimate goal, though, has always been the same: to create a visual story with a distinct mood that will captivate the viewing audience. In film, the first shot of a scene, known as the establishing shot, is used not only to set the time and place of the story, but also introduce the mood. This thesis involves the study of establishing shots from five contemporary films to determine how to manipulate specific visual elements that promote mood, specifically a dark and ominous mood. Through this study, an original computer generated establishing shot will be created that successfully communicates a similar dark mood. The visual analysis used to achieve this goal can be adapted to various other genres of film and can serve as a guide for future artists to create comparable work.

Visual storytelling has come a long way since primitive man began creating colorful, narrative cave paintings. In this new age of technology, motion pictures have become a prevalent medium for visual storytelling throughout the developed world. Filmmakers have the added advantage of being able to create more and more fantastic settings and stories with the introduction of computer generation images (CGI). They also gain a fine degree of control over the visual elements of the final product. The ultimate goal, though, has always been the same: to create a visual story with a distinct mood that will captivate the viewing audience. In film, the first shot of a scene, known as the establishing shot, is used not only to set the time and place of the story, but also introduce the mood. This thesis involves the study of establishing shots from five contemporary films to determine how to manipulate specific visual elements that promote mood, specifically a dark and ominous mood. Through this study, an original computer generated establishing shot will be created that successfully communicates a similar dark mood. The visual analysis used to achieve this goal can be adapted to various other genres of film and can serve as a guide for future artists to create comparable work.

Thesis (M.S.)--Ohio State University, 1986. / Includes bibliographical references (leaves 120-123). Available online via OhioLINK's ETD Center

Made available in DSpace on 2014-06-11T19:27:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-27Bitstream added on 2014-06-13T20:08:17Z : No. of bitstreams: 1 tonoli_cs_me_guara.pdf: 6263213 bytes, checksum: b9be92a4785ed36cad560de2367c06a8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O tubo superior do garfo suspensão é um dos componentes de grande importância no conjunto de peças que compõe uma bicicleta, pois durante a operação é submetido a carregamentos cíclicos e caso falhe pode causar acidentes ao ciclista. Este componente é confeccionado por processo de usinagem a partir de um perfil tubular extrudado em liga de alumínio Al 6013-T6. Neste trabalho foi realizado um estudo sobre o comportamento em fadiga desta liga de alumínio submetida a diferentes condições de shot peening, objetivando aumentar a resistência à fadiga do material e conseqüentemente aumentar a vida útil/segurança do componente. Para ensaiar os corpos-de-prova em perfil tubular com geometria embasada nas dimensões do tubo superior, desenvolveu-se uma metodologia especifica de ensaio. Os ensaios mostraram que o processo de fabricação de rosca por conformação mecânica aumentou consideravelmente a resistência à fadiga dessa liga em relação ao processo de fabricação por usinagem convencional. Os efeitos de concentradores de tensão como filetes de rosca usinada e defeitos superficiais são extremamente prejudiciais para a vida em fadiga da liga Al 6013-T6. Os tratamentos de shot peening realizados pela empresa Zirtec induziram um perfil significativo de tensões residuais compressivas, porém, reduziram a vida em fadiga da liga Al 6013-T6 em perfil tubular. Esse efeito foi potencializado com intensidades Almen elevadas. O aumento na vida em fadiga ocorreu apenas nos corpos-de-prova que foram lixados na superfície interna. O shot peening com esfera de vidro e intensidade Almen intermediária apresentou a maior vida em fadiga. Os resultados deste trabalho estão sendo usados para providenciar melhorias na matéria prima e como base para novos ensaios com o tubo superior. / The fork supension's steerer tube is one of component of great importance in a set that makes a bicycle, since during operation is subjected to cyclic loading and if fails may cause accident to the rider. This component is manufactured by machining processes from the extrusion tubular profile in aluminum alloy 6013-T6. This work carried out a study on the fatigue behavior of aluminum alloy subjected to different shot peening conditions, proposing to increase the fatigue strength and consequently to increase a useful life/safety of the component. To test tubular profile specimen with geometry based in steerer tube dimensions, has developed a specific methodology for testing. The tests showed that thread forming by manufacturing process, increase the fatigue strength of this aluminum alloy comparing the manufacturing process through conventional machining. The effects of concentration stress like machined thread and surface defects are extremely detrimental to fatigue life alloy AL 6013-T6. Shot peenig treatment carried out in Zirtec company induced a significant compressive residual stress profile, but decrease the fatigue life alloy Al 6013-T6 in tubular profile. This effect was strengthened with high Almen intensities. The fatigue life incresase ocurred only specimen that were polished on the inner surface. Shot peening using glass shot and intermediate Almen intensity had the greatest fatigue life. The results os this work are being used to provide improvements in primary material and as a basis for new test on the stereer tube.

O objetivo deste trabalho foi estudar diferentes rotas de fabricação de um componente automotivo e avaliar quais destas rotas permitiriam o atendimento dos requisitos técnicos com possibilidade de redução dos custos de fabricação. Os fabricantes de autopeças estão inseridos em um mercado de alto risco e elevada competitividade, assim, estes fabricantes, arcam com diversos custos para atendimento de requisitos, em alguns casos exigentes em demasia e desnecessários, por parte do cliente. O foco de componentes automotivos deve se basear em requisitos de natureza mecânica, como resistência a tração, resistência ao impacto, resistência a fadiga, etc. O desempenho mecânico de um componente depende do seu processo de fabricação e da matéria-prima utilizada, sendo estes os dois fatores de maior importância e representatividade no custo de fabricação de um componente. O processo de fabricação de um componente mecânico específico foi simulado fisicamente com duas matérias primas alternativas disponíveis no fabricante e com dois tratamentos térmicos distintos, além da utilização de shot peening no final do processo, gerando 8 diferentes rotas de fabricação Foram avaliados os aços SAE 1045H e DIN 38MnVS6 como opções de matéria-prima alternativa, além dos tratamentos térmicos de têmpera e revenimento e resfriamento em esteira. Foram realizadas análises de composição química e microestrutural para cada aço e tratamento térmico, além de avaliação de dureza, resistência a tração, resistência ao impacto, análise de tensões residuais e desempenho em fadiga. Os requisitos de dureza e resistência mecânica foram satisfatórios para todas as condições, exceto para o SAE 1045H com resfriamento em esteira. O desempenho em fadiga dos materiais sem shot peening não foram satisfatórios, apenas para o DIN 38MnVS6 com resfriamento em esteira apresentou desempenho próximo ao esperado, sendo todas rotas de fabricação sem shot peening reprovadas. Para os materiais com shot peening, apenas o SAE 1045H apresentou resultado insatisfatório, os demais materiais atenderam a especificação de fadiga. Pôde ser observada a influência das tensões residuais superficiais compressivas no desempenho em fadiga do componente, além disto, foi verificado a possibilidade de produzir o componente em três diferentes rotas de produção, podendo gerar uma redução de custo de até 12%. / The aim of this work was to study different manufacturing routes of an automotive component and, meantime, evaluate which of these routes would allow the fulfillment of technical requirements with the possibility of reducing manufacturing costs. Auto parts manufacturers are placed in a high-risk and highly competitive market, in addition to shouldering costs to meet requirements in some demanding and, sometimes, unnecessary cases by the customer. The focus of automotive components should be based on requirements of a mechanical nature, such as tensile strength, impact resistance, fatigue resistance, etc . The mechanical performance of a component depends on the manufacturing process and raw material used, these being the two most important factors in the representation and manufacturing cost of a component. The manufacturing process of a particular mechanical component was physically simulated with two alternative materials, both available from the manufacturer with two different heat treatments, in addition to the use of shot peening by the end of the process, generating eight different manufacturing routes. Were evaluated the SAE 1045H steel and DIN 38MnVS6 as an alternative raw material, in addition to heat treatment of quenching and tempering, the current process, and forced air cooling Chemical and microstructural analysis of each steel composition and heat treatment were performed, in addition to evaluation of hardness, tensile strength, impact resistance, analysis of residual stresses and fatigue performance. The requirements of mechanical properties were satisfactory for all conditions except for the SAE 1045H air-cooled. The fatigue performance of materials without shot peening were not satisfactory, only for DIN 38MnVS6 air cooled the performance was close to the specification, so all manufacturing routes without shot peening were disapproved. For materials with shot peening, only the SAE 1045H presented non-satisfactory result, other materials attended fatigue specification. It was observed the influence of surface compressive residual stresses in the component fatigue performance, furthermore, it was verified the possibility of producing the component three different routes, allowing a cost reduction up to 12%.

Previous field studies of hunter-harvested mourning doves (Zenaida macroura) have reported lead (Pb) shot ingestion rates of 1 &ndash 6.5%. However, considerable uncertainty exists concerning mechanisms affecting pellet ingestion across different habitats. To reduce some of this uncertainty, an experiment was conducted to test the Pb shot ingestion rate of mourning doves on bare soil (typical of a managed dove field). Wild doves were trapped and held in captivity 5 &ndash 13 weeks prior to treatment. One week prior to treatment, a blood sample was taken from each bird before placement in open-bottomed treatment pens on a disked field. Each of 3 treatment groups of 80 birds was divided into 35 low density (1.5 million pellets/ha), 35 high density (29.5 million pellets/ha), and 10 control (0 pellets/ha) animals. Five positive control birds were gavage &ndash dosed with 2 Pb shot in trials 2 and 3. Pb shot and mixed seed were scattered uniformly on the loosely packed soil of their pens and birds were exposed for 4 days. Birds were x &ndash rayed post &ndash treatment on days 2 and 4 for the presence of Pb shot in the digestive system, and euthanized following the drawing of a blood sample on day 4. Overall, 2.9% of doves voluntarily ingested &ge 1 pellet. The shot ingestion rate for birds in the high density Pb treatment (4.9%) was not statistically different (P = 0.0977) from birds in the low density Pb treatment (1.0%). Pb concentrations in liver, kidneys, and blood reached maxima of 94.402, 346.033, and 13.883 ppm wet weight, respectively, and were statistically greater in birds that had ingested shot than in controls (P < 0.0083). Delta-aminolevulinic acid dehydratase (ALAD) activity decreased by an average of 92.2% post-treatment as compared to pre-treatment in birds that had ingested shot, while increasing by 1.1% in control birds. Heterophil:lymphocyte ratio increased by 28.2% in birds that ingested shot as compared to 1.5% in controls, while packed cell volume decreased by 7.6% in birds that ingested shot and 0.6% in controls. No significant difference in weight among groups was observed post-treatment (P = 0.3131). If managers deem the number of mourning doves at risk of Pb shot ingestion unacceptable, some options are to ban Pb shot either on entire management areas or only on high shot deposition areas like dove fields, or to disk fields after dove hunting to reduce Pb shot availability.