Power, dissipated total

In addition, it was concluded that the liquid-phase diffusion coefficient is the major factor influencing the value of the mass-transfer coefficient per unit area. Inasmuch as agitators operate poorly in gas-liquid dispersions, it is impractical to induce turbulence by mechanical means that exceeds gravitational forces. They conclude, therefore, that heat- and mass-transfer coefficients per unit area in gas dispersions are almost completely unaffected by the mechanical power dissipated in the system. Consequently, the total mass-transfer rate in agitated gas-liquid contacting is changed almost entirely in accordance with the interfacial area—a function of the power input. 

Pressure variation. In Figure 17 are shown the effects of total pressure on the relative pressures (i.e., the ratio of the partial pressure to the total pressure) of silane, hydrogen, and disilane (Fig. 17a) and on the deposition rate (Fig. 17b). The RF frequency is 50 MHz, and the plasma power is 5 W. The relative pressure of hydrogen slowly increases, and the relative pressure of silane slowly decreases, both in model as well as in experiment. This is caused by an increase in silane depletion at higher total pressures, which results from a higher power dissipation... 

Probe diameter Description Total power dissipated into the reactor (W/m3) Crystallite size (nm) Particle size distribution (nm) Induction time (min)... 

Fig. 27. Thermally balanced PP and NP sequences. (PP) In the balanced PP sequence, the sample is first kept at the relaxation field By for a time — t and, then pre-polarized at the polarization field Bp for a time Tp, and finally allowed to relax for time T before the start of the detection period. The time Tp should be set to about 4Ti(Bp). As T varies during a multi-block sequence, the polarization interval position moves horizontally but the total block duration and the mean power dissipation remain constant. (NP) The balanced non-polarized sequence is conceptually similar, except for the fact that the polarization interval is replaced by a magnetization annihilation interval in which the field is zero and whose duration should be about 47 (0). In both cases, the time should be about or more than 4Ti(Br). The concept can be combined with any detection mode, not just the simple FID detection shown here.

The specific power dissipated by agitators in the liquid, eagit, was measured by a strain gauge mounted on the impeller shaft. The total specific power e dissipated in the liquid by the agitator and the rising bubbles was calculated as e = eagjt + pgvs. The volumetric mass transfer coefficient and interfacial area were measured by the Danckwerts plot method described in detail in Part I. 

The overall volumetric mass transfer coefficients measured by pure oxygen absorption were expressed as a function of the total specific power dissipated in the liquid as follows ... 

Fig. 2. kLa/(vs)0A measured by pure oxygen absorption as a function of total power dissipated in the liquid, e. Symbols and lines (see Table 1). 

The total power (energy/time) dissipated per unit volume of fluid in this system is the sum of the power dissipated due to fluid viscosity and the power dissipated by friction between the pore fluid the counterions pinned in the fluid7. For two-dimensional flow the power dissipated due to fluid viscosity is given by ([5]),... 

Fig. 9.30 Graphical representation of the various components of the total power consumption in the solids conveying zone of screw extruders for H/Di, = 0.15 and a constant fs/fb ratio as a function of the angle (f> Pwb, which is the major component of the power, is the power dissipated into heat at the barrel plug interface Pws and Pwf are the power dissipated on the root of the screw and flights, respectively and Pwp is the power consumed for the pressurization of the plug. [Reprinted by permission from E. Broyer and Z. Tadmor, Solids Conveying in Screw Extruders, Part I. A Modified Isothermal Model, Polym. Eng. Sci., 12, 12-24 (1972).]...

In the context of resonant acoustic devices, Q =fiJBW, where fn is the resonant frequency and BW is the bandwidth it can equivalently be defuied as loU Pj, where o> is the angular frequency. Up is the peak total energy present in the device, and is the power dissipated by the device. For resonant systems, BW is the range of frequencies over which the reflected power is within 3 dB (a factor of two) of its minimum value, attained at fit, for non-resonant systems (e.g., delay lines), BW is the range of iiequencies over which the transmitted power is within a factor of two of its maximum value. 

An interesting study of the gas liquid mass transfer in a three-phase agitated slurry reactor was recently reported by Joosten et al.51 They showed that in the absence of solids, the volumetric mass-transfer coefficient can be well correlated to total power (power dissipated by stirrer + gas) per unit volume, but poorly correlated to the power dissipated by the stirrer only, as done in Fig. 9-14. Their data were well correlated by the correlation of Van Dierendock.23... 

Using EES (or other) software, investigate the effects of air velocity at (lie inlet of the channel and (he maximum surface temperature on the maximum total power dissipation of electronic components. Let the air velocity vary from I m/s to lO m/s and the surface temperature from 30°C to 90 C. Plot the power dissipation as functions of air velocity and surface temperature, and discuss the results. 

The heat flux was varied for every fixed mass flow rate in order to obtain a series of outlet vapour qualities between 0.2 and 1 with a step of 0.05. Steady state values were monitored using a Hewlett Packard 3421A with a 30 minutes time lapse between each mass flow rate or heat flux change. Averaging was carried out after every 20 values and uncertainties were calculated according to the Kline and McClintock (1953) method. The total electrical power dissipated in the test section was calculated as the product of voltage and current. The variations of R134a thermophysical properties with temperature were calculated with the REFPROP 6.01 software. 

The area of the parallelogram represents the total power dissipated in the cell when the parallelogram bridge circuit and the oscilloscope are calibrated in the following manner ... 

A,- = 2jrr L being the interface area, and the second term denoting the friction power dissipated into heat. With Fourier s conduction and Newton s cooling laws (Step 3), expressing the outward q in terms of total (conductive plus convective) resistances over the temperature drop T, — Too,... 

To consider the temperature dependent leakage power consumption, it is desired to determine the transistor layer temperature distribution due to the power dissipated. For this purpose, the two transistor layers are laterally partitioned into M = 2 x N x N bins based on a user-specified granularity. Then, full-chip thermal simulation is applied to compute the average temperature increase in all bins if a unit power is dissipated in any of these bins. The power and temperature interactions for a particular power dissipating bin are illustrated in Fig. 5.6. A total of M x M interactions will be extracted at this stage such that for any given on-chip power dissipation distribution, the temperature increase at any of the two transistor layers can be determined by superposition at the specified granularity 23. Stated mathematically, we have... 

The increased viscosity in a shear flow due to the introduction of particles can be associated with the increased energy dissipation due to the introduced solid boundaries. For a dilute solution the total dissipation with the particles present can be taken to be the energy dissipation per unit time without the particles plus the power dissipation associated with rotating the particles relative to the flow. From this and the fact that for a small volume fraction of spherical particles the perturbation velocity induced by a particle is u a y r where a is the particle radius, r is the radial distance, and y is the applied shear rate, show that the functional form for the relative viscosity is given by 17 = 1 -I- Be/), where B is a constant and is the particle volume fraction. 

The problem is totally different for dielectric loss. The wave is attenuated as it traverses the medium and, therefore, the power dissipated is reduced to an even larger extent. Consequently, the propagation constant becomes complex as described by Eq. (63) ... 

The resistance R2/S represents the total power dissipated in one phase winding of the rotor. This consists of a resistive loss in the winding itself and the shaft power transmitted to the mechanical load. The resistance can be divided into two parts -... 

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