Power specific

The rate of a process is expressed by the derivative of a concentration (square brackets) with respect to time, d[ ]/dt. If the concentration of a reaction product is used, this quantity is positive if a reactant is used, it is negative and a minus sign must be included. Also, each derivative d[ ]/dt should be divided by the coefficient of that component in the chemical equation which describes the reaction so that a single rate is described, whichever component in the reaction is used to monitor it. A rate law describes the rate of a reaction as the product of a constant k, called the rate constant, and various concentrations, each raised to specific powers. The power of an individual concentration term in a rate law is called the order with respect to that component, and the sum of the exponents of all concentration terms gives the overall order of the reaction. Thus in the rate law Rate = k[X] [Y], the reaction is first order in X, second order in Y, and third order overall. 

Eigure 6 enables a comparison to be made of kj a values in stirred bioreactors and bubble columns (51). It can be seen that bubble columns are at least as energy-efficient as stirred bioreactors in coalescing systems and considerably more so when coalescence is repressed at low specific power inputs (gas velocities). 

Fig. 25. Lithium—sulfur dioxide and lithium —tbionyl chloride high rate batteries profile with (a) power density vs energy density, and (b) specific power vs...

From equation 60 one can obtain a theoretical power requirement of about 900 kWh/SWU for uranium isotope separation assuming a reasonable operating temperature. A comparison of this number with the specific power requirements of the United States (2433 kWh/SWU) or Eurodif plants (2538 kWh/SWU) indicates that real gaseous diffusion plants have an efficiency of about 37%. This represents not only the barrier efficiency, the value of which has not been reported, but also electrical distribution losses, motor and compressor efficiencies, and frictional losses in the process gas flow. 

The rotor speed of the scaled up tower is based on maintaining the same specific power input number as used on the pilot column it can be determined by substituting the specific values into the relationship ... 

FIG. 20-37 Specific power of ftead and ftall mills [Kolb, Ceramic Forum International, 70(5), 212-6 (1993)]. 

These items are highly site specific. Power cost is low because the salinity removed by the selected plant is low. The quality of the feed water, its sahnity, turbidity, and concentration of problematic ionic and fouhng solutes, is a major variable in pretreatment and in conver-... 

It has been emphasised in the earlier chapters that the thermal efficiency of the gas turbine increases with its maximum nominal temperature, which was denoted as T. Within limits this statement is true for all gas turbine-based cycles and can be sustained, although not indefinitely, as long as the optimum pressure ratio is selected for any value of Ty, further the specific power increases with T. However, in practice higher maximum temperature requires improved combustion technology, particularly if an increase in harmful emissions such as NO is to be avoided. 

Figure 2.15 Local specific power input to agitated vessels for several stirrers (after Mersmann and Geisler, 1991)...

While thin polymer films may be very smooth and homogeneous, the chain conformation may be largely distorted due to the influence of the interfaces. Since the size of the polymer molecules is comparable to the film thickness those effects may play a significant role with ultra-thin polymer films. Several recent theoretical treatments are available [136-144,127,128] based on Monte Carlo [137-141,127, 128], molecular dynamics [142], variable density [143], cooperative motion [144], and bond fluctuation [136] model calculations. The distortion of the chain conformation near the interface, the segment orientation distribution, end distribution etc. are calculated as a function of film thickness and distance from the surface. In the limit of two-dimensional systems chains segregate and specific power laws are predicted [136, 137]. In 2D-blends of polymers a particular microdomain morphology may be expected [139]. Experiments on polymers in this area are presently, however, not available on a molecular level. Indications of order on an... 

New materials can improve the specific energy of the automobile battery, which is attracting most of the scientific effort. Nevertheless, an increase in specific power can only be obtained by a good understanding of the structural and molecular aspects that affect the electrochemistry of these materials. 

Fig. 18. Comparison of results from various particle systems for stirred vessel with baffles and bubble columns Activity a/ao of Acylase resin after t = 300 h, equilibrium drop diameter dg of silicon oil-water-surfactant emulsion and reference floe diameter dpv of floe system in dependency on specific power P/V H/D = 1 D = 0.15 m 0.4 m...

To clarify the laws of scale, investigations were conducted in geometrically strictly similar tanks having volumes V = 20,50, and 7301. For the same specific power, both the floe disintegration kinetics (Fig. 3) and the reference floe diameter (see Fig. 21) produce similar numerical values for all three scales. The same was also found for the other material systems. 

Biichs J, Zoels B (1999) Evaluation of the Maximiun Specific Power Consumption in Shaking Bioreactors, Proceedings of 3th International Symposium on Mixing in Industrial Processes (ISMlP-3) 19-22 Sept 1999 Japan... 

For plant cell suspensions cultivated in shake flasks, Huang et al. [45] used the energy dissipation rate as a correlating parameter for system response. Specific power input was calculated using the empirical correlation proposed by Sumino et al. [46] and subsequently employed in other applications [47,48] ... 

Energy conversion method/fliel Efficiency (%) Power (kW) Specific power(Wkg) Range Powerdensity automobiles (W/liter) (km) Cost ( /kW) Environmental safety... 

Widely used parameters are the specific energy or power per unit mass (w = W/M, in Wh/kg, orp = P/M, in W/kg). In each battery type the specific energy is a falling function of specific power. Plots of w vs. p (Ragone, 1968) yield a clear illustration of the electrical performance parameters of given types of batteries and are very convenient for their comparison (see Fig. 19.4). 

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