Fracture

The projection of geographic coordinates of artesianism points of
Upper Cretaceous aquifer on the fractures map of southwestern part of the Bénin coastal sedimentary basin revealed a significant relationship between artesian wells and fracturations. The artesian wells are aligned along fractures oriented NNE-SSW derived from the reactivation of Kandi fault. The artesianism of Upper Cretaceous aquifer, resulting in drilling wells and water oozing, would be related to effects of topography and the arrangement of geological layers and faults.

Bisphosphonates currently represent the main therapy in the fight against osteoporosis. This is a serious condition, with an increasing incidence, presently affecting about 12 million people in the U.S. mostly women aged over 50 years. Thus, approximately 40% -50% of them suffer an osteoporotic fracture. Bisphosphonates mechanism of action consists in reducing osteoclast-mediated bone resorption, modifying bone turn over, leading to an increase in bone density. This dramatically reduces the risk of fracture. Although bisphosphonates shows a good safety profile, lately emerged some alarm signals that link their long management to some unusual side effects. Bisphosphonates is an effective therapy to combat osteoporosis, their causal relationship with FAF production not being shown. In the absence of other evidence, it is unclear whether BF therapy is directly involved in producing FAF or only a component of a combination of factors, in reality being just an indicator of a severe degre...

Fractal measurements using the Cantor's dust method in a linear one-dimensional analysis mode were made on the fracture patterns revealed on two-dimensional, planar surfaces in four granites. This method allows one to conclude that: (1) The fracture systems seen on two-dimensional surfaces in granites are consistent with the part of fractal theory that predicts a repetition of patterns on different scales of observation, self similarity. Fractal analysis gives essentially the same values of D on the scale of kilometres, metres and centimetres (five orders of magnitude) using mapped, surface fracture patterns in a Sierra Nevada granite batholith (Mt. Abbot quadrangle, Calif.). (2) Fractures show the same fractal values at different depths in a given batholith. Mapped fractures (main stage ore veins) at three mining levels (over a 700 m depth interval) of the Boulder batholith, Butte, Mont. show the same fractal values although the fracture disposition appears to be different at different levels. (3) Different sets of fracture planes in a granite batholith, Central France, and in experimental deformation can have different fractal values. In these examples shear and tension modes have the same fractal values while compressional fractures follow a different fractal mode of failure. The composite fracture patterns are also fractal but with a different, median, fractal value compared to the individual values for the fracture plane sets. These observations indicate that the fractal method can possibly be used to distinguish fractures of different origins in a complex system. It is concluded that granites fracture in a fractal manner which can be followed at many scales. It appears that fracture planes of different origins can be characterized using linear fractal analysis.

The plane elasticity problem studied is of a circular inclusion having a circular arc-crack along the interface and a crack of arbitrary shape in an infinite matrix of different material subjected to uniform stresses at infinity. The solution of the problem is given using Muskhelishvili's complex variable method with sectionally holomorphic functions. First, the solution to the (auxiliary) problem of a dislocation (or force) applied at a point in the matrix with the circular inclusion partially bonded is derived fully in its general form by solving the appropriate Rieman-Hilbert problem. It is subsequently used as the Green's function for the initial problem by introducing an unknown density function associated with a distribution of dislocations along the crack in the matrix. The initial problem is then reduced to a singular integral equation (SIE) over the crack in the matrix only. The SIE is solved numerically by appropriate quadratures and the stress intensity factors ...

atteinte pulpaire apres traumatisme dentaire est frequente. L'evolution de la pulpe apres ce traumatisme est variable. La pulpe peut soit cicatriser soit se necroser et entrainer des complications peri-apicales. La necrose pulpaire doit etre diagnostiquee le plus precocement possible afin de prevenir les complications pouvant survenir au niveau de la region apicale. Cet article propose de revoir les criteres cliniques permettant le diagnostic de la necrose apres traumatisme dentaire.

SummaryA Brazilian orthopaedic company designed a stainless steel plate called Synthesis Pengo System (S.P.S.), which has one fixed and one changeable extremity. According to the assembly of the changeable extremity, it is possible to obtain dynamization or neutralization of the fracture site. Since the S.P.S. plate was developed for use in human patients, the aim of this study was to evaluate this system in long-bone diaphyseal fractures in dogs. Eight dogs with closed diaphyseal fractures of the femur (n= 1), radius and ulna (n=5), and tibia (n=2) were used. Patients were aged seven months to three years and weighed 18 to 31.2 kg. The S.P.S. plate was assembled with one fixed extremity and one changeable extremity in dynamization mode. The trail bar was positioned for synthesis modules with holes for cortical screws. The modules were positioned close to one another in two fractures and far away from the fracture site in the others. The bone healing occurred by external callus. Sin...

This paper presents a methodology for predicting the thresholds of multiple site damage and widespread fatigue damage in fuselage lap slices. Widespread fatigue damage is a type of multiple cracking that reduces the airframe residual strength to a level below the damage tolerant requirement. The MSD threshold refers to the point in the lifetime of an airplane when two adjacent

High ranking burial mounds in Bronze Age Sudan featured burials in a corridor leading to the central burial – supposedly of a king. Were the ‘corridor people’ prisoners captured during periodic raids on Egypt, or local retainers who followed their king in death? The authors use the skeletal material to argue the second hypothesis – coincidentally that advanced by George Reisner, the original excavator.

We explore the compliance approach for K I evaluation of a cracked three point beam (TPB) of functionally graded material (FGM). We suggest an equivalent beam of variable height for cracked FGM beams which includes the homogeneous beam for the linear, quadratic and cubic variations in elastic modulus along the beam span. The efficacy of equivalent beams is demonstrated numerically on a 250 × 41 × 6 mm FGM beam with modulus varying from 210 – 315 GPa under 5000 N load.

Distal radius fracture often presents a metaphyseal void which is more extended in elderly, osteoporotic patients. Bone graft and bone substitutes are reported to be beneficial in maintaining metaphyseal reduction. We performed a prospective study on 52 menopausal, osteoporotic women with unstable intra-articular distal radius fractures to compare the outcome of percutaneous pinning and immobilisation in a cast for 6 weeks with that using injectable calcium phosphate bone cement (Norian Skeletal Repair System, SRS) to supplement pin and screw fixation and immobilisation in a cast for 3 weeks. All patients were reviewed 2 years (range 21-29 months) after surgery. Patients treated with SRS had better functional outcome, restoration of movement and grip strength ( p<0.001). In this group there was 1 mm loss of radial length, 3 degrees loss of radial inclination and 7 degrees loss of palmar tilt. In the control group radial length decreased 3 mm, radial inclination decreased 11 degre...