72 resultados para brocas


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[ES]Este proyecto se basa en la idea de llevar a cabo un código CAM de un diseño anterior (CAD). El modelo CAD consiste en una broca, que está diseñado específicamente para perforar materiales apilados, como el titanio y fibra de carbono que son ampliamente utilizados por la industria de la aviación en la actualidad. Para lograr este objetivo se sería necesario contar con los recursos adecuados, licencias de software, soporte de fábrica y por supuesto el conocimiento de la materia. Este texto tiene como objetivo la ceración del código CAM, así como demostrar la rentabilidad de este método de mecanizado alternativo.

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Tesis ( Maestro en Ciencias de la Administración con Especialidad en Finanzas) - U.A.N.L, 2002

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Apraxia of speech (AOS) is typically described as a motor-speech disorder with clinically well-defined symptoms, but without a clear understanding of the underlying problems in motor control. A number of studies have compared the speech of subjects with AOS to the fluent speech of controls, but only a few have included speech movement data and if so, this was primarily restricted to the study of single articulators. If AOS reflects a basic neuromotor dysfunction, this should somehow be evident in the production of both dysfluent and perceptually fluent speech. The current study compared motor control strategies for the production of perceptually fluent speech between a young woman with apraxia of speech (AOS) and Broca’s aphasia and a group of age-matched control speakers using concepts and tools from articulation-based theories. In addition, to examine the potential role of specific movement variables on gestural coordination, a second part of this study involved a comparison of fluent and dysfluent speech samples from the speaker with AOS. Movement data from the lips, jaw and tongue were acquired using the AG-100 EMMA system during the reiterated production of multisyllabic nonwords. The findings indicated that although in general kinematic parameters of fluent speech were similar in the subject with AOS and Broca’s aphasia to those of the age-matched controls, speech task-related differences were observed in upper lip movements and lip coordination. The comparison between fluent and dysfluent speech characteristics suggested that fluent speech was achieved through the use of specific motor control strategies, highlighting the potential association between the stability of coordinative patterns and movement range, as described in Coordination Dynamics theory.

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Metal-ceramic interfaces are present in tricone drill bits with hard ceramic inserts for oil well drilling operations. The combination of actions of cutting, crushing and breaking up of rocks results in the degradation of tricone drill bits by wear, total or partial rupture of the drill bit body or the ceramic inserts, thermal shock and corrosion. Also the improper pressfitting of the ceramic inserts on the bit body may cause its total detachment, and promote serious damages to the drill bit. The improvement on the production process of metal-ceramic interfaces can eliminate or minimize some of above-mentioned failures presented in tricone drill bits, optimizing their lifetime and so reducing drilling metric cost. Brazing is a widely established technique to join metal-ceramic materials, and may be an excellent alternative to the common mechanical press fitting process of hard ceramic inserts on the steel bit body for tricone drill bit. Wetting phenomena plays an essential role in the production of metal/ceramic interfaces when a liquid phase is present in the process. In this work, 72Silver-28Copper eutectic based brazing alloys were melted onto zirconia, silicon nitride and tungsten carbide/Co substrates under high vacuum. Contact angle evolution was measured and graphically plotted, and the interfaces produced were analysed by SEM-EDX. The AgCu eutectic alloy did not wet any ceramic substrates, showing high contact angles, and so without chemical interaction between the materials. Better results were found for the systemns containing 3%wt of titanium in the AgCu alloy. The presence os titanium as a solute in the alloy produces wettable cand termodinamically stable compounds, increasing the ceramics wetting beahviour

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The present work begins with a review of the literature on bit selection methods for oil well drilling. A proposal for the structure and organization of a drilling database and a knowledge base, is described. Previous studies formed the principal elements in the process of selection of drills for proposed drilling. The procedure was implemented as a computer system for the selection of tricone bits. A drilling bit database for three different Brazilian sedimentary basins was obtained for several wells drilled, and knowledge was collected from drilling engineers from different fields both electronically and also by means of interviews. It can be concluded that the selection process showed good results based on tests, which were carried out.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Nine swines of the White Large race were used for study of the process of bony repair after osteotomy with rotating instruments of low and high-speed, with and without liquid refrigeration. The authors observed, through double blind histopathological analysis, that in every analyzed operative time, the bony repair was processed more appropriately when the osteotomies were accomplished with liquid refrigeration. In the final postoperative times, of fourteen and twenty-eight days, the best results of bony repair were observed in the osteotomy accomplished with drills of low rotation and with liquid refrigeration, while in the postoperative time of seven days, the results of the bony repair of osteotomy accomplished with drills of high rotation and with liquid refrigeration they were better. The authors consider, still, that the process of bony repair in swine display larger proximity in the histological pictures among the studied variables, when compared with other biological models. As most of the works told in the literature it refers the use of dogs, the authors consider that the present work guarantees your importance in the sense of looking for a closer model of the man.

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Metal-ceramic interfaces are present in tricone drill bits with hard ceramic inserts for oil well drilling operations. The combination of actions of cutting, crushing and breaking up of rocks results in the degradation of tricone drill bits by wear, total or partial rupture of the drill bit body or the ceramic inserts, thermal shock and corrosion. Also the improper pressfitting of the ceramic inserts on the bit body may cause its total detachment, and promote serious damages to the drill bit. The improvement on the production process of metal-ceramic interfaces can eliminate or minimize some of above-mentioned failures presented in tricone drill bits, optimizing their lifetime and so reducing drilling metric cost. Brazing is a widely established technique to join metal-ceramic materials, and may be an excellent alternative to the common mechanical press fitting process of hard ceramic inserts on the steel bit body for tricone drill bit. Wetting phenomena plays an essential role in the production of metal/ceramic interfaces when a liquid phase is present in the process. In this work, 72Silver-28Copper eutectic based brazing alloys were melted onto zirconia, silicon nitride and tungsten carbide/Co substrates under high vacuum. Contact angle evolution was measured and graphically plotted, and the interfaces produced were analysed by SEM-EDX. The AgCu eutectic alloy did not wet any ceramic substrates, showing high contact angles, and so without chemical interaction between the materials. Better results were found for the systemns containing 3%wt of titanium in the AgCu alloy. The presence os titanium as a solute in the alloy produces wettable cand termodinamically stable compounds, increasing the ceramics wetting beahviour