Fatigue general

There is no evidence that nutritional deficiencies lead to decreased learning, performance, depression, disorientation, fatigue, general malaise, apathy, and headaches. 

Failure and decay of mechanical properties after repeated applications of stress or strain are known as fatigue. Generally the "fatigue life" is defined as the number of cycles of deformation required to bring about rupture (see also Chap. 13). 

Although not specific for liver dysfunction, patients with all types of liver disease often present with extreme fatigue and malaise. The fatigue generally worsens throughout the day. It is not a measure of extent of liver impairment, but can have a major effect on quality of life. 

Failiu-e of a component due to fatigue generally occurs through a two-step process. The first step involves the initiation of microcracks or other damage at inhomogeneities or defects in the material. This damage can initiate and evolve... 

Shiftwork not only increases fatigue generally but also puts the shiftworker on the road during potentially hazardous times. The general advice is to drive defensively or even to consider other modes of transport. 

More prone to fatigue General effects of aging... 

Illness or fatigue general poor health or injury... 

Fracture Mechanics. Linear elastic fracture mechanics (qv) (LEFM) can be appHed only to the propagation and fracture stages of fatigue failure. LEFM is based on a definition of the stress close to a crack tip in terms of a stress intensification factor K, for which the simplest general relationship is... 

When constant stress (5) amplitudes are encountered, the process is known as high cycle fatigue, because failure generally occurs only when N exceeds 10 cycles. Data from high cycle fatigue tests are reported in the form of an 5 vs Ai curve, as shown in Figure 4b (7). 

High temperature fatigue and fretting fatigue behavior has also been improved by implantation (113,114). This has been achieved by using species that inhibit oxidation or harden the surface. It is generally accepted that fretting behavior is closely coimected to oxidation resistance, perhaps due to third party effects of oxidation products. Oxidation resistance alone has also been improved by ion implantation (118—120). 

The geometry of the bowl parts is important, and for intermittently discharging centrifuges, fatigue strength must be considered. In general the tangential stress in a bowl wall is CJ. ... 

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