Availability velocity

Example 27.5 Air moving in a duct at 8 m/s is gently expanded to a velocity of 5.5 m/s. If the friction losses are 20% of the available velocity pressure change, what is the amount of static regain ... 

By proper selection of scales (ji) for availability, velocity and mass, can be set equal to unity for convenience, this has been done in Eq. (39) and will be done throughout the remainder of this paper.) Equation (39) can be rearranged into... 

Using probability theory, the following expression was obtained as the basic rotational transfer function. In practice, this expression is summed over available velocities weighted by their individual probabilities. 

As m increases, At becomes progressively smaller (compare the difference between the square roots of 1 and 2 (= 0.4) with the difference between 100 and 101 (= 0.05). Thus, the difference in arrival times of ions arriving at the detector become increasingly smaller and more difficult to differentiate as mass increases. This inherent problem is a severe restriction even without the second difficulty, which is that not all ions of any one given m/z value reach the same velocity after acceleration nor are they all formed at exactly the same point in the ion source. Therefore, even for any one m/z value, ions at each m/z reach the detector over an interval of time instead of all at one time. Clearly, where separation of flight times is very short, as with TOF instruments, the spread for individual ion m/z values means there will be overlap in arrival times between ions of closely similar m/z values. This effect (Figure 26.2) decreases available (theoretical) resolution, but it can be ameliorated by modifying the instrument to include a reflectron. 

Computer codes are used for the calculational procedures which provide highly detailed data, eg, the Ruby code (70). Rapid, short-form methods yielding very good first approximations, such as the Kamlet equations, are also available (71—74). Both modeling approaches show good agreement with experimental data obtained ia measures of performance. A comparison of calculated and experimental explosive detonation velocities is shown ia Table 5. 

This effect of concentration is particularly pronounced with irregularly shaped particles. A possible explanation of the variation in the specific resistance is in terms of the time available for the particles to orient themselves in the growing cake. At higher concentrations, but with the same approach velocities, less time, referred to as particle relaxation time, is available for a stable cake to form and a low resistance results. 

Enough space must be available to properly service the flow meter and to install any straight lengths of upstream and downstream pipe recommended by the manufacturer for use with the meter. Close-coupled fittings such as elbows or reducers tend to distort the velocity profile and can cause errors in a manner similar to those introduced by laminar flow. The amount of straight pipe required depends on the flow meter type. For the typical case of an orifice plate, piping requirements are normally Hsted in terms of the P or orifice/pipe bore ratio as shown in Table 1 (1) (see Piping systems). 

Two modes of operation are available. In the simpler mode, a fixed current is appHed to the wire. In the other mode, the sensor temperature (hence is maintained at a fixed value above that of the gas by means of a feedback amplifier. In both cases, velocity is measured by the voltage drop. 

The porosity appears in the denominator of the right-hand side of the equaUty owing to the dependence of velocity on the available flow area, which is reduced from the total cross-sectional area by the factor n. 

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