نتایج جستجو برای: grain drill
تعداد نتایج: 67405 فیلتر نتایج به سال:
Background/Aim During drilling implant sites, mechanical energy is converted into thermal one resulting in transient rise in temperature of surrounding bone. The temperature of 47°C exeeding one minute impairs osseointegration, compromises mechanical properties of the local bone and could cause early implant failure. This in vitro study aimed to assess the effect of surgical drill guide and tem...
INTRODUCTION Our objective was to compare the effectiveness, speed, and complication rate of the traditional manually placed intraosseous (IO) catheter to a mechanical drill-assisted IO catheter by emergency medicine (EM) resident physicians in a training environment. METHODS Twenty-one EM residents participated in a randomized prospective crossover experiment placing 2 intraosseous needles (...
OBJECTIVE Retreatment of a root canal in the case of infection requires complete removal of previous filling material. This study evaluated the efficacy of 3 techniques in removing laterally compacted Resilon/Epiphany and gutta-percha/AH Plus from straight and curved canals during retreatment. MATERIALS AND METHODS Extracted human teeth (90 maxillary anterior teeth with single,straight root c...
Drilling-induced delamination is among the major concerns of applying the fiber-reinforced composite materials in various industries. Core drill ossesses the advantage for reducing the delamination by distributing the drilling thrust force toward the drill periphery. The thrust force of core rill varying with the conditions in drilling carbon fiber reinforced plastic (CFRP) is experimentally in...
The aim of this study was to evaluate histomorphometrically the influence of two techniques of dental implant site preparation on bone healing around titanium implants. Fifteen male Wistar rats (±300 g) were used in the study. Each tibia was randomly assigned to receive the implant site preparation either with a conventional drilling technique (control - DRILL group) or with a piezoelectric dev...
On the UK Continental Shelf, up to 80,000 tonnes wet weight of oily drill cuttings are produced annually. These are heterogeneous wastes generated from the petroleum drilling industry, composed of significant percentages of hydrocarbons, heavy metals and chlorides. Since 1992, the discharge of drill cuttings containing more than 1% oil-on-cuttings has been prohibited. Moreover, the extensive in...
To investigate the origin of fractures at the distal locking site of the Gamma nail, we loaded ten paired human cadaver femora fixed with a Gamma nail in torsion until they fractured. When an awl was hammered in to start the hole for distal locking a fissure appeared in the lateral cortex of all the femora, and the mean torsional load to create a fracture was reduced by 57.8% compared with that...
We studied the various drill bits available for engineering purposes, and compared them with standard orthopaedic drill bits, using continuous temperature recording at 0.5 mm, 1.0 mm and 1.5 mm from the edge of a 2.5 mm hole as it was drilled in fresh cadaver human tibia. We found that some commercially available drill bits performed better than their orthopaedic equivalents, producing signific...
A reliable method of transmitting downhole information to the surface while drilling is essential to improve drilling applications. We have designed a numerical algorithm for simulation of electric-signal transmission through the drill string, based on the telegrapher equation (a circuit model). The drill string is then represented by a transmission line with varying geometrical and electromagn...
Fibre reinforced plastics are increasing their importance as one of the most interesting groups of material on account of their low weight, high strength and stiffness. To obtain good quality holes, it is important to identify the type of material, ply stacking sequence and fibre orientation. In this paper, the drilling of quasi-isotropic hybrid carbon+glass/epoxy plates is analyzed. Two commer...
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