Primary measures

There are do2ens of flow meters available for the measurement of fluid flow (30). The primary measurements used to determine flow include differential pressure, variable area, Hquid level, electromagnetic effects, thermal effects, and light scattering. Most of the devices discussed herein are those used commonly in the process industries a few for the measurement of turbulence are also described. 

Combustion. The primary reaction carried out in the gas turbine combustion chamber is oxidation of a fuel to release its heat content at constant pressure. Atomized fuel mixed with enough air to form a close-to-stoichiometric mixture is continuously fed into a primary zone. There its heat of formation is released at flame temperatures deterruined by the pressure. The heat content of the fuel is therefore a primary measure of the attainable efficiency of the overall system in terms of fuel consumed per unit of work output. Table 6 fists the net heat content of a number of typical gas turbine fuels. Net rather than gross heat content is a more significant measure because heat of vaporization of the water formed in combustion cannot be recovered in aircraft exhaust. The most desirable gas turbine fuels for use in aircraft, after hydrogen, are hydrocarbons. Fuels that are liquid at normal atmospheric pressure and temperature are the most practical and widely used aircraft fuels kerosene, with a distillation range from 150 to 300 °C, is the best compromise to combine maximum mass —heat content with other desirable properties. For ground turbines, a wide variety of gaseous and heavy fuels are acceptable. 

Pigglomerates are undispersed clusters of aggregates held together by van der Waals forces or by biaders. The term stmcture is used to describe both the extent and the complexity with which the particles are iatercoimected ia aggregates. Primary measures of stmcture focus on the internal space within the aggregate. 

Screw compressors use both Babbitt and rolling-element bearings. Because of the thrust created by process instability and the normal dynamics of the two rotors, all screw compressors use heavy-duty thmst bearings. In most cases, they are located on the outboard end of the two rotors, but some designs place them on the inboard end. The actual location of the thmst bearings must be known and used as a primary measurement-point location. 

In most cases, measurement-point locations for compressors are identical to those of pumps and fans. If a compressor is V-belt driven, the belts on the inboard and outboard bearings should in a plane opposing the sideload create the primary measurement point. The secondary point should be at 90° to the primary point. 

The primary measure of baghouse-system performance is its ability to consistently remove dust and other particulate matter from the dirty-air stream. Pressure drop and collection efficiency determine the effectiveness of these systems. 

Intelligent transmitters have two major components (1) a sensor module which comprises the process connections and sensor assembly, and (2) a two-compartment electronics housing with a terminal block and an electronics module that contains signal conditioning circuits and a microprocessor. Figure 6.9 illustrates how the primary output signal is compensated for errors caused in pressure-sensor temperature. An internal sensor measures the temperature of the pressure sensor. This measurement is fed into the microprocessor where the primary measurement signal is appropriately corrected. This temperature measurement is also transmitted to receivers over the communications network. 

Scott and Reese chose to monitor retention volume as opposed to retention time, as retention volume is always the primary dependent variable in LC. Retention time is not a primary measurement because it must also include the reproducibility of the flow-rate delivered by... 

Values in kJ/mol calculated from primary measurements using updated reference thermochemical data provided in references 127,128, and 10. 

The primary measure of the amount of free radical must depend on those properties unambiguously due to the unpaired electron. In the past the most common method has been the measurement of the paramagnetic susceptibility, now subject to difficulties of quantitative interpretation. The method of paramagnetic resonance absorption is... 

Operational performance, primary measurements of, 20 731 Operational qualification (OQ), in fine chemical production, 11 433 Operational systems, for sustainable development, 24 190 Operational testing, piping system,... 

Primary measurements, of operational performance, 20 731 Primary metabolites... 

In this chapter, the primary measurement techniques for droplet properties are outlined, and their capabilities and limitations are discussed. The approaches to intelligent process control as related to droplet processes are presented along with descriptions of recent developments. 

The terminator of drug action is, of course, elimination. Elimination is a composite of excretion (kidney, etc.) and biotransformation (metabolism). The primary measure of drug elimination from the whole body is clearance, CLt, defined as the volume of plasma fluid removed of drug per unit time. It is a direct measure of the loss of the drug from the system and can be calculated from Eq. (3.5) after IV administration of a dose of the drug. 

Gravimetric analysis is a wet chemical method of analysis in which the measurement of weight is the primary measurement, and most of the time the only measurement, that is made on the analyte and its matrices. 

As a primary measure in this direction the Authorities of the Emilia Romagna Region have passed a law whereby the volume of manure farmers store must correspond to production over a 90 day period. The law aims at avoiding spreading in winter months and reducing, in part, the pathogenic bacterial count. 

PCDD/F are emitted by the flue gas of the incineration plants. Primary measures have become very important in the production and technology of chemistry as the... 

Inhibition Technology as Primary Measure for PCDD/F Minimization... 

The control of NO from stationary sources includes techniques of modification of the combustion stage (primary measures) and treatment of the effluent gases (secondary measures). The use oflow-temperature NO,.burners, over fire air (OFA), fiue gas recirculation, fuel reburning, staged combustion and water or steam injection are examples of primary measures they are preliminarily attempted, extensively applied and guarantee NO reduction levels of the order of 50% and more. However, they typically do not fit the most stringent emission standards so that secondary measures or flue gas treatment methods must also be applied. 

For this purpose, in addition to the continuous evolution of CR and exhaust gas recirculation (EGR), novel primary measures are under study, including the long route EGR to cool the recirculated exhaust gas, the use of premixed combustion [which implies, however, higher GO and unburned hydrocarbon (U HG) emissions], the reduction of the compression ratio, the shaping of the injection rate and so on. Still, the after-treatment catalytic technologies for O, removal and for CO/hydro-carbon (HG) and particulate matter (PM) reduction in passenger cars must be improved significantly. 

All types of measuring devices in which the material passes without being divided into isolated quantities. Movement of the material is usually sensed by a primary measuring element which activates a secondary device. The flow rate is then inferred from the response of the secondary device by means of known physical laws or from empirical relationships. 

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