Point of measurements

Indicator—A device that measures a process variable and displays that variable at the point of measurement. 

It is important for predictive maintenance programs using vibration analysis to have accurate, repeatable data. In addition to the type and quality of the transducer, three key parameters affect data quality the point of measurement, orientation, and transducer-mounting techniques. 

The best method of ensuring that the point of measurement, its orientation, and the compressive load are exactly the same each time is to permanently or hard mount the transducers, which is illustrated in Figure 43.26. This guarantees accuracy and repeatability of acquired data. However, it also increases the initial cost of the program. The average cost of installing a general-purpose accelerometer is about 300 per measurement point or 3000 for a typical machine-train. 

Complete bleaching with non-zeolite case was achieved after 20 minutes of treatment, trend of the curve which connects points of measured TOC removals is almost linear, zeolite addition caused delay in decolorization of RB137, while NH4ZSM5 zeolite addition showed positive effect to TOC removal after 30. minute of process. But it should be pointed out that final achieved mineralization, 69.3 % TOC removal, by UV/O3/H2O2 process is somewhat higher than that obtained by UV/O3 process, 64.4 % TOC removal. 

What then is the point of measuring surface excess It will be shown that the surface excess affects many quantities, for example, the interfacial tension at the interlace and the way in which it depends upon concentration. In fact it will be shown (see. Section 6.5.1) that surface excess can be experimentally determined from thermodynamic measurements without recourse to modeling arguments. 

What Is the Point of Measuring System Pressure Effects A... 

Figure 5. A time-temperature firing schedule of the thermal gradient furnace at the 12 thermocouple points of measurement...

The use of the weakly bound electron in a Rydberg atom to measure low energy electron attachment rate constants has proven to be one of the more useful applications of Rydberg atoms. Measurements have been refined to the point of measuring the lifetimes of negative ions formed by attachment,96 and it is likely that further developments will follow. 

Example 13.4. The result of a typical X-ray measurement is shown in Fig. 13.10 for a galactocerebroside [605], The plot on the left side shows the normalized reflected X-ray beam intensity versus the incident angle a for two different film pressures. The pressure-area isotherm is shown in the inset, together with the points of measurement a and b. On the right side are the extracted electron density profiles normal to the film surface taken at the same film pressures. At 0 A we find the monolayer surface (top of the alkyl chains), a depth of -40 A corresponds to pure water. In between is the film. The measurement is so sensitive that we even find two different electron densities within the monolayer. This is illustrated by the dashed boxes denoted by film 1 and film 2 (shown for curve b only) which represents the simplified electron density distribution in the so-called two-box model. A box is defined as a part in the film of a certain thickness where the electron density is constant. In the two-box model the film is divided into two layers. Film 1 represents the hydrocarbon tails, film 2 corresponds to the mean electron density of the head groups. 

It takes a lot more than just connecting an IR instrument to a pipe to make the instrument into a process analyzer. The system not only has to be constructed correctly and be capable of flawless operation 24 hours a day, but it also has to be packaged correctly, and be able to access the stream correctly and without any interference from process-related disturbances such as bubbles, water, particulates, etc. Finally, the data acquired from the instrument has to be collected and converted into a meaningful form and then transmitted to the process computer, where the information is used to assess the quality of the product and to report any deviations in the production. Beyond that point, the process computer, typically not the process analyzer, handles any decisions and control issues. There are a few exceptions where robotics are integrated with the analyzer, and good vs. bad product quality are assessed at the point of measurement. The use of... 

Filled-System Thermometers The filled-system thermometer is designed to provide an indication of temperature some distance removed from the point of measurement. The measuring element (bulb) contains a gas or liquid that changes in volume, pressure, or vapor pressure with temperature. This change is communicated through a capillary tube to a Bourdon tube or other pressure- or volume-sensitive device. The Bourdon tube responds so as to provide a motion related to the bulb temperature. Those systems that respond to volume changes are completely filled with a liquid. Systems that respond to... 

Gibson method. The mean velocity in a penstock leading from a reservoir can be determined by rapidly closing a valve at the lower end and recording a pressure-time diagram at a point just upstream from the valve. The principle that impulse equals change of momentum can be applied to the mass of liquid between the reservoir and the point of measurement. The impulse is given by the area under the recorded pressuretime curve, and from this the initial velocity can be determined [10]. 

The static pressure under a liquid, column is isotropic and is determined by the height of the column above the point of measurement, h, and the density of the liquid p... 

Always connect the gauge as close as possible to the area where measurements need to be made. The farther away the gauge is from the point of measurement, the longer the lag time before the system and the gauge come to equilibrium. The greater the vacuum (> 10 5 torr), the more pronounced this effect. 

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