Fatigue prevention

Rosenberg E, Caine Y. Survey of Israeli Air Force line commander support for fatigue prevention initiatives. Aviat Space Environ Med 2001 72 352-356. 

Lighting is an important part of the work enviromnent. It has a direct impact on safety prevention of fatigue prevention of eye problems and product quality. Eye strain can be caused by subjecting the eye to bright light and glare. Eye strain may cause inflammation, headaches and general tiredness. 

There was serious worker fatigue and no fatigue prevention policy. 

Several approaches to corrosion fatigue prevention exist. On one hand, we can take measures to reduce the rate of corrosion by some of the techniques discussed in Chapter 17—for example, apply protective surface coatings, select a more corrosion-resistant material, and reduce the corrosiveness of the environment. On the other hand, it might be advisable to take actions to minimize the probability of normal fatigue failure, as outlined previously—for example, reduce the applied tensile stress level and impose residual compressive stresses on the surface of the member. 

Bellows can vibrate, both from internal fluid flow and externally imposed mechanical vibrations. Internal flow liner sleeves prevent flow-induced resonance, which produces bellows fatigue failure in minutes at high flow velocities. Mechanically induced resonant vibration is avoided by a bellows with a natural frequency far away from the forcing frequency, if known. Multiple-ply bellows are less susceptible to vibration failure because of the damping effect of interply friction. 

Calcium—Silicon. Calcium—silicon and calcium—barium—siUcon are made in the submerged-arc electric furnace by carbon reduction of lime, sihca rock, and barites. Commercial calcium—silicon contains 28—32% calcium, 60—65% siUcon, and 3% iron (max). Barium-bearing alloys contains 16—20% calcium, 9—12% barium, and 53—59% sihcon. Calcium can also be added as an ahoy containing 10—13% calcium, 14—18% barium, 19—21% aluminum, and 38—40% shicon These ahoys are used to deoxidize and degasify steel. They produce complex calcium shicate inclusions that are minimally harm fill to physical properties and prevent the formation of alumina-type inclusions, a principal source of fatigue failure in highly stressed ahoy steels. As a sulfide former, they promote random distribution of sulfides, thereby minimizing chain-type inclusions. In cast iron, they are used as an inoculant. 

More important than either creep or fatigue in current car design is the effect of environmerit (Chapter 23). An appreciable part of the cost of a new car is contributed by the manufacturing processes designed to prevent rusting and these processes only partly work - it is body-rust that ultimately kills a car, since the mechanical parts (engine, etc.) can be replaced quite easily, as often as you like. 

Subjective evaluation of odor emission is made difficult by the phenomenon of odor fatigue, which means that after persons have been initially subjected to an odor, they lose the ability to perceive the continued presence of low concentrations of that odor. Therefore, all systems of subjective odor evaluation rely on preventing olfactory fatigue by letting the observer breathe odor-free air for a sufficient time prior to breathing the odorous air and evaluating its odor content. Usually an activated charcoal bed is... 

It is a disadvantage of all photomultipliers that the photocurrent is not completely proportional to the strength of illumination. Further, the photocurrent must not exceed 10 A or the photomultiplier becomes fatigued. Daylight switches are incorporated into some scanners for this reason in order to prevent over-illumination of the detector when the sample chamber is opened. 

Baffles can be omitted when propeller mixers are top mounted at an angular off-center position (see Figure 5-23D) and vortex swirling is prevented. This is not recommended for large povver systems on large tanks, due to shaft fatigue. 

Note When rupture disk devices are used, it is recommended that the design pressure of the vessel be sufficiently above the intended operating pressure to provide sufficient margin between operating pressure and rupture disk bursting pressure to prevent premature failure of the rupture disk due to fatigue or creep. 

In square-forged kellys, the decarburized zone has been removed from the corners of the fillet between the drive section and the upset to prevent fatigue cracks. Hexagonal kellys have machined surfaces and are generally free of decarburized zone in the drive section. 

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