Hand fractures

Fig. 3.4 Groundwater accumulating in a syncline. Well I, located at the syncline, has a significantly higher production then well II, located in an adjacent anticline. The lowering of the water table, due to pumping, will cut well II dry in a short time. On the other hand, fracturing in the crest of an anticline occasionally makes these locations better places for water supply.

Relative to the phalanges the metacarpals are reasonably protected, although several series of hand fractures found the fifth metacarpal to be the most frequently injured bone (Rajesh et al. 2001 Vadivelu et al. 2006). Incidence peaks in older schoolchildren, when the mechanism of injury is usually punching, or involvement in contact sports. 

Graham TJ, Waters PM (2001) Fractures and dislocations of the hand and carpus in children, in Beaty JH, Kasser JR (eds) Rockwood and Wilkins Fractures in children, 5th edn. Lip-pincott Williams and Wilkins, Philadelphia, pp 271-379 blastings H, Simmons BP (1984) Hand fractures in children. 

Ljungberg E, Rosberg HE, Dahlin LB (2003) Hand injuries in young children. J Hand Surg [Br] 28 376-380 Mahabir RC, Kazemi AR, Cannon WG, Courtemanche DJ (2001) Pediatric hand fractures a review. Pediatr Emerg Care 17 153-156... 

Rajesh A, Basu AK, Vaidhyanath R, Finlay D (2001) Hand fractures a study of their site and type in childhood. Clin Radiol 56 667-669... 

On the other hand, fracture toughness, K c, is defined as the following equation. 

Fractures are important for fluid flow in oil, gas, and water production and geothermal processes. In such cases, the fluids are stored mainly in the matrix porosity but produced primarily using fracture permeability. Fractures penetrating impermeable shale layers create hydraulic conductivity and can develop a reservoir. Artificial fracturing (hydrofrac) can create new fractures or magnify existing fracture. On the other hand, fractures significantly reduce mechanical rock properties. 

It is very important to recognise that fracture is inseparable from deformation. Yet, deformation and fracture are distinctly different phenomena. In general, for characterising deformation, the test piece is deformed uniformly. Otherwise, the stress-strain relationship becomes too complex to describe. Even for the treatment of a complex non-imiform deformation, it is sub-divided into small elements, which are assumed to deform imiformly. On the other hand, fracture originates from microscopic flaw, which is an extreme case of non-uniformity. Under the driving force of the stored mechanical energy, the flaw grows to become the fracture surface. 

On the other hand, fracture mechanics theory suggests the rupture may be due to weak intercrystalline affinity [18-21], agglomeration of amorphous regions [22-24], or some combination thereof [9,18], However, these broad mechanisms are unlikely to be mutually exclusive, and they lead to similar mathematical representations differing only in the rate-controlling step of many kinetic phenomena [6,10], Because the Zhurkov theory is more widely-accepted and has a well-developed basis in physics, it will be highlighted here. 

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