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...

Compositional distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in Nigerian oil-based drill-cuttings have been studied for evidence of petrogenic and/or pyrogenic effects with recommendations for the strict enforcement of the ban on the use of oil-based mud in drilling by government regulatory agencies and prior bio-treatment of the drill cuttings before final fate. Laboratory...

The drill & blast method is still the most typical method for medium to hard rock conditions. It can be applied to a wide range of rock conditions. Some of its features include versatile equipment, fast start-up and relatively low capital cost tied to the equipment. On the other hand, the cyclic nature of the drill & blast method requires good work site organization. Blast vibrations and noise ...

Hole drilling operations are common in fibre reinforced plastics FRP’s to facilitate fastener assembly to other parts in more complex structures. As these materials are non-homogeneous, drilling causes some damages, like delamination, for example. Delamination can be reduced by a careful selection of drilling parameters, drill material and drill bit geometry. In this work two types of laminates...

The treatment of fractures in osteopetrosis can be complicated and difficult. We describe the use of an industrial grade tungsten carbide drill bit in the treatment of one of these complex fractures. An industrial grade tungsten carbide drill bit was used to fashion a medullary canal in the surgical treatment of a left peri-implant fracture of the neck of femur in a patient with osteopetrosis. ...

The effect of periodic vibration noise in wellsite is an important factor which impact analysis on three-dimensional drill string vibration signal. In order to obtain more accurate characters of three-dimensional drill string vibration signal that reflects the drilling tools condition, we conduct researches on the periodic vibration noise in the wellsite, independent component analysis algorith...

Pelvic ring fractures that occur as a result of substantial orthopedic trauma are frequently repaired using iliosacral screws to stabilize the fracture. Stimulus evoked electromyography, using pulsed current stimuli provided through the drill bit cathode, has been advocated to prevent nerve root injury during iliosacral screw insertion. Our objective was to examine the effects of anode location...