نتایج جستجو برای: geometrical drilling
تعداد نتایج: 41314 فیلتر نتایج به سال:
Ring removal is indicated in a number of clinical circumstances to manage or prevent tourniquet effect of the digit. A ring made from hardened metal may defy commonly known methods of removal. We reported a case of unusual difficulty in removing a ring of hardened metal composition using a dental drill. We believed the unusual circumstances of this case is likely to be repeated in some other cl...
The study of rotary steering drilling technology is currently one of the hot topics in the drilling engineering field. It requires accurate well trajectory control instructions when rotary steerable tools are applied to achieve the well trajectory control goal. A drilling trajectory prediction model will benefit this progress. According to the continuous beam theory, a mechanical model of push-...
In oil and gas and geothermal installations, open channels followed by sieves for removal of drill cuttings, are used to monitor the quality and quantity of the drilling fluids. Drilling fluid flow rate is difficult to measure due to the varying flow conditions (e.g., wavy, turbulent and irregular) and the presence of drilling cuttings and gas bubbles. Inclusion of a Venturi section in the open...
This paper is concerned with optimal strategies for drilling in an oil exploration model. An exploration area contains n1 large and n2 small oilfields, where n1 and n2 are unknown, and represented by a two-dimensional prior distribution π. A single exploration well discovers at most one oilfield, and the discovery process is governed by some probabilistic law. Drilling a single well costs c, an...
The purpose of this study was to develop a novel measurement method using a machine vision system. Besides using image processing techniques, the proposed system employs a detection line algorithm that detects the tool electrode length and drilling depth of a workpiece accurately and effectively. Different boundaries of areas on the tool electrode are defined: a baseline between base and normal...
BACKGROUND The possibility of physeal injury during anterior cruciate ligament reconstruction in the pediatric population is a concern. The purpose of this study was to determine whether drilling at or near the physis could cause a temperature increase that could trigger chondrolysis. METHODS Skeletally immature cadaveric lamb distal femurs were used for this study and randomly placed in 1 of...
Feasibility of drilling with supercritical carbon dioxide to serve the needs of deep underbalanced drilling operations has been analyzed. A case study involving underbalanced drilling to access a depleted gas reservoir is used to illustrate the need for such a research. For this well, nitrogen was initially considered as the drilling fluid. Dry nitrogen, due to its low density, was unable to ge...
PURPOSE The aim of the study was to examine the influence of a short drilling protocol on peri-implant crestal bone levels. MATERIALS AND METHODS Forty implants were placed in the posterior mandibles of 20 patients. The implants (diameter, 4.2 mm; length, 10 to 11.5 mm) were inserted in pairs: one implant was inserted using the standard drilling protocol (five drills in sequence), while the o...
The aim of this work is to analyze the micro mechanisms underlying the wear of macroscale tools during diamond machining of SiCp/Al6063 composites and to develop the mechanism-based diamond wear model in relation to the dominant wear behaviors. During drilling, high volume fraction SiCp/Al6063 composites containing Cu, the dominant wear mechanisms of diamond tool involve thermodynamically activ...
BACKGROUND The purpose of our study was to investigate the impact of distracting noise on the performance on a simulated orthopedic bone drilling skill when that noise blocks routine auditory feedback associated with the sounds of the drill. METHODS Medical students (n=11), intermediate residents (postgraduate years 3-5, n=10) and surgeons (n=8) each drilled 20 bicortical holes in a femur bon...
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