Process measurements measurement span

For process measurements, accuracy as a percent of span is the most common. 

Section 8 outlines the following criteria for selection of measurement devices measurement span, performance, reliability, materials of construction, prior use, potential for releasing process materials to the environment, electrical classification, physical access, invasive or noninvasive, and life-cycle cost. 

CH3CF3 Reaction Mechanism. The CH3CF3 measurements span the range 0.3 (P/Z) 170 atm, and the detailed mechanism analysis has been presented elsewhere (3,14,15,34). In addition to the F-to-HF process shown in Reaction 17, five energetic primary reactions are important in the gas phase (Reactions 53-57). The respective primary yields have been included in Table XL. 

A representative instrument [Kondraske et al., 1984 Kondraske, 1990] is illustrated in Figure 78.4. This device incorporates 8 LEDs and 15 high-speed touch sensors ( home, A1-A8 and B1-B6) and a dedicated internal microprocessor to measure an array of different performance capacities associated with information-processing. Measures at the most basic hierarchical level (visual information-processing speed, visual-spatial memory capacity, visual attention span, etc.) and intermediate level (coordination tasks involving different sets of more basic functional units) are included. 

Measurement range (span). The required measurement range for the process variable must lie entirely within the instrument s range of performance. 

As normally used in the process industries, the sensitivity and percentage of span accuracy of these thermometers are generally the equal of those of other temperature-measuring instruments. Sensitivity and absolute accuracy are not the equal of those of short-span electrical instruments used in connection with resistance-thermometer bulbs. Also, the maximum temperature is somewhat limited. 

The flow capacity of the transducer can be increased bv adding a booster relav like the one shown in Fig, 8-7.3/ , The flow capacity of the booster relav is nominally fiftv to one hundred times that of the nozzle amplifier shown in Fig, 8-7.3 3 and makes the combined trans-diicer/booster suitably responsive to operate pneumatic actuators. This type of transducer is stable into all sizes of load volumes and produces measured accuracy (see Instrument Society of America [ISA]-S5l, 1-1979, Process Instrumentation Terminology for the definition of measured accuracy) of 0,5 percent to 1,0 percent of span. 

In order to supplement micro-mechanical investigations and advance knowledge of the fracture process, micro-mechanical measurements in the deformation zone are required to determine local stresses and strains. In TPs, craze zones can develop that are important microscopic features around a crack tip governing strength behavior. For certain plastics fracture is preceded by the formation of a craze zone that is a wedge shaped region spanned by oriented micro-fibrils. Methods of craze zone measurements include optical emission spectroscopy, diffraction... 

BCFs and BAFs measured before the steady state is reached have little value because they are dependent on the period of exposure of the organism to the chemical, and thus may greatly underestimate the degree of biomagnification that is possible. This statement should be qualified by the reservation that there may be situations in which the duration of exposure cannot be long enough for the steady state to be reached, for example, where the life span of an insect is very short. The principal processes of uptake and loss by different types of organisms are indicated in Table 4.1 (see also Box 4.2). 

The most significant results obtained for complexes of iron(II) are collected in Table 3. The data derive from laser Raman temperature-jump measurements, ultrasonic relaxation, and the application of the photoperturbation technique. Where the results of two or three methods are available, a gratifying agreement is found. The rate constants span the narrow range between 4 x 10 and 2 X 10 s which shows that the spin-state interconversion process for iron(II) complexes is less rapid than for complexes of iron(III) and cobalt(II). 

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