Span measurement

The development of maturity and complexity of the wine is a relatively slow process. While we occasionally observe significant increases in these characteristics in as little as three months, it is more common to find increases in maturity and complexity over time spans measured in years. Some of the white wines of the Northwest are allowed to mature in the bottle for up to one year prior to release for sale. These wines are usually either sweet or are truly dry white wines. Typical examples would be botrytized or late harvest White Rieslings and Chardonnays. The red wines of the Northwest generally are aged in the bottle for one year or more prior to release. A notable exception in recent years has been wines of the V. vinifera cultivar Merlot, offered by several wineries in Washington with six months or less bottle age. 

Comment pressure transmitters deliver signals but require power. You can set the zero, span, measurement scale and range, and more. They are pricey but very... 

FIGURE 23.10 Sum-of-the-dlagonals for Intersection span measurement (G. Molinda et al. 1998)... 

GE changed its measurement system towards what it calls Span measurement. Span stands for the range of delivery around customer-requested due dates. Essentially, the company now measures, across all deliveries globally, how close it was to the delivery date the customer requested when ordering. In its plastics business the company brought Span down from 30 days to just a few days within... 

Field of view Widest angular span measured on the sky that can be imaged distinctly by the optics. 

Remick and Geankoplis made flux measurements for both species in the isobaric diffusion of nitrogen and helium through their tube bundle. Pressures spanned the interval from 0.444 nim, Hg to 300,2 ram Hg, which should cover the whole range between the limits of Knudsen streaming and bulk diffusion control. Then, since K and K, are known in this case, the form of the proposed flux relations could be tested immediately by plotting the left hand side of equation (10.15) against... 

In quantum meehanies, physieally measurable quantities are represented by hermitian operators. Sueh operators R have matrix representations, in any basis spanning the spaee of funetions on whieh the R aet, that are hermitian ... 

Spanning, accompHshed using a sample gas containing a known volume concentration of impurity, is performed at levels that are the same order of magnitude as the required detection. The actual span concentration is selected so that the majority of expected measurements fall at or within its value. 

Vacuum measurement spans the range from 10 Pa (atmospheric pressure) to pressures that are less than 10 orders of magnitude. Sub atmospheric pressures are divided into six regions for convenience (9) ... 

Another frequentiy used average is the geometric mean, which is particularly usehil for log-normal or wider (spanning over a decade) distributions. The geometric mean diameter, d is calculated usiag the logarithm values of the measured diameters ... 

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

Manufacturers of measurement devices always state the accuracy of the instrument. However, these statements always specify specific or reference conditions at which the measurement device will perform with the stated accuracy, with temperature and pressure most often appearing in the reference conditions. When the measurement device is apphedat other conditions, the accuracy is affected. Manufacturers usually also provide some statements on how accuracy is affected when the conditions of use deviate from the referenced conditions in the statement of accuracy. Although appropriate cahbration procedures can minimize some of these effects, rarely can they be totally eliminated. It is easily possible for such effects to cause a measurement device with a stated accuracy of 0.25 percent of span at reference conditions to ultimately provide measured values with accuracies of 1 percent or less. Microprocessor-based measurement devices usually provide better accuracy than the traditional electronic measurement devices. 

Measurement span. The measurement span required for the measured variable must lie entirely within the instrument s envelope 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. 

In each case, transmission of a single value in only one direction is required. Such requirements can be met by analog signal transmission. A span is defined for the value to be transmitted, and the value is basically transmitted as a percent of this span. For the measured variable, the logical span is the measurement span. For the controller output, the logical span is the range of the final actuator (e.g., valve fully closed to valve fully open). 

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. 

The analytical range is determined by the instrumental design. For this method, a portion of the analytical range is selected by choosing the span of the monitoring system. The span of the monitoring system is selected such that the pollutant gas concentration equivalent to the emission standard is not less than 30 percent of the span. If at any time during a rim the measured gas concentration exceeds the span, the rim is considered invahd. 

The minimum detectable limit depends on the analytical range, span, and signal-to-noise ratio of the measurement system. For a well-designed system, the minimum detectable limit should be less than 2 percent of the span. 

The upper hmit of a gas concentration measurement range is usually 1.5 to 2.5 times the applicable emission limit. If no span value is provided, a span value equivalent to 1.5 to 2.5 times the expected concentration is used. For convenience, the span value should correspond to 100 percent of the recorder scale. 

Large instrument spans required to address variety of operating condi-tions/requirements may result in inadequate measurement and control at the low or high end of their spans. 

Location of faults by the direct current method is based on the application of Ohm s Law. It is assumed that, because of the good pipe coating, virtually no current passes into the measured span and that the longitudinal resistance R is known. When the fault-locating current, I, is fed in and takes a direct path via the foreign line to the protected pipeline, the fault distance is determined from the voltage drop AU over the measured span ... 

This simplification is only permissible with very low-resistanee eontaet and if no other eurrent flows in the pipeline. Currents flowing in the pipeline outside the measured span must be measured separately and taken aeeount of in the ealeula-tion. This follows also indirectly when loeating a eontaet with an unknown line. Figure 3-21 shows the neeessary pipe eurrent measurements on either side of the supposed eontaet point whieh, with U = Ul =1R, gives the following ealeula-tion of the fault distanee [28] ... 

The determination of AU values as well as the potential is effected by simple measurements of the difference in potential between two reference electrodes over the pipeline. To reduce possible electrode errors, partial sums can also be measured for a larger span, e.g., (a - O ) = 300 m ... 

The U.S. Environmental Protection Agency has established National Ambient Air Quality Standards (NAAQS) for protection of human health and welfare. These standards are defined in terms of concentration and hme span for a specific pollutant for example, the NAAQS for carbon monoxide is 9 ppmV for 8 hr, not to be exceeded more than once per year. For a state or local government to establish compliance with a National Ambient Air Quality Standard, measurements of the actual air quality must be made. To obtain these measurements, state and local governments have established stationary monitoring networks with instrumentation complying with federal specifications, as discussed in Chapter 14. The results of these measurements determine whether a given location is violating the air quality standard. 

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