Stress operator characteristics

It is worth stressing that the AQL is simply the defect percentage level which defines the 95% probability of acceptance. From the example it is obvious that there are other probabilities which can be calculated and, if graphed, provide the operating characteristic (OC) of that sampling plan, i.e. 

There is virtually no creep and very litde permanent deformation. Similar tests have furthermore shown that there is not much more deformation even after 8000 hours exposure to 4000 psi. The added benefit of this low creep and strain recovery characteristic of tape is that it confers operating shock absorbency and smoothness to energy transfer mechanisms, not or less provided by other energy transmission devices since featuring steeper stress/strain characteristics or no stress elasticity at all. 

It is possible to speak about the influence of material substructure of a spring on operational characteristics by spring camber research data, relaxation resistance under cyclic loads, fatigue life test and the failure stress values. 

Other differences in the mechanical properties of superfibers are most clearly manifested in their operating characteristics. The stress-strain diagram of Kevlar-29 fibers at different temperatures and rates of deformation is shown in Fig. 10.14 [88]. The strength of the fibers decreases by 14% on average with an increase in the rate of deformation from 0.167 to 8000%/sec. The elongation at break virtually does not change. The shape of the curves is almost linear. 

Materials of Construction and Operational Stress. Before a centrifugal separation device is chosen, the corrosive characteristics of the Hquid and soHds as weU as the cleaning and saniti2ing solutions must be deterrnined. A wide variety of materials may be used. Most centrifuges are austenitic stainless steels however, many are made of ordinary steel, mbber or plastic coated steel. Monel, HasteUoy, titanium, duplex stainless steel, and others. The solvents present and of course the temperature environment must be considered in elastomers and plastics, including composites. 

A characteristic feature of thermoplastics shaped by melt processing operations is that on cooling after shaping many molecules become frozen in an oriented conformation. Such a conformation is unnatural to the polymer molecule, which continually strives to take up a randomly coiled state. If the molecules were unfrozen a stress would be required to maintain their oriented conformation. Another way of looking at this is to consider that there is a frozen-in stress corresponding to a frozen-in strain due to molecular orientation. 

The extent to which a particular combination of such "operating environment" factors will be perceived by the workers as being stressful will depend on the available resources such as the quality of the control panel, procedures, training, organizational and social factors, and, finally, the individual characteristics of the workers. The outcome of this transaction between stress factors and coping resources will influence the onset of worker stress. Situations are not stressful merely because of the presence of a number of external stressors, but because they are perceived as such by workers. 

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