Empirical coefficient

C = empirical coefficient, equal to 15 for small shallow pools and 11 for large deep reservoirs... 

Relatively easy to measure. The main disadvantage is that the empirical coefficients may change with changing environmental conditions, requiring measurement. 

An assumption implicit in most adsorption studies is that adsorption is fully reversible. In other words, once the empirical coefficients are measured for a particular substance, Equations 20.6 to 20.10 describe both adsorption and desorption isotherms. This assumption is not always true. Collins and Crocker140 observed apparently irreversible adsorption of phenol in flowthrough adsorption experiments involving phenol interacting on a Frio sandstone core under simulated deep-well... 

Mills and colleagues58 describe the use of these formulations to predict aerobic biodegradation in surface waters and present methods of adjusting for temperature and nutrient limitations. This approach to predicting biodegradation is problematic because it is difficult to obtain empirical coefficients in the deep-well setting. 

This model significantly simplifies the computations of the IAS model, although it does not improve its accuracy [15,27,76,88]. One popularized approach to modify the IAS model is to incorporate an empirical coefficient (Rt) into Eq. (29) to describe more accurately experimental equilibria [76,95,101,102] as the following ... 

The signals were recorded as electrical potential in millivolts. The well known Maxwell s formula and an adjustable empirical coefficients were used to obtain the equivalent volume fraction of liquid [43]. Since it is known that kinematic waves exist only in the frequency of some few Hertz, hardware low pass filter with 20 Hz cutting frequency was included for each channel in the electronic unit. The filter was tuned at 82.66 Db. Data were acquired by a computer at 100 Hz. The following comments regarding the above apparatus description are in order ... 

The first term again represents drag in steady motion at the instantaneous velocity, with Cd an empirical function of Re as in Chapter 5. The other terms represent contributions from added mass and history, with empirical coefficients, Aa and Ah, to account for differences from creeping flow. From measurements of the drag on a sphere executing simple harmonic motion in a liquid, Aa and Ah appeared to depend only on the acceleration modulus according to ... 

The relationship between the number concentration (AO of CCN and the supersaturation (S) is often expressed in the form N = CSk, where C and k are empirical coefficients characteristic of the particular air mass (Pruppacher and Klett, 1997). However, alternate forms such as... 

Yet, in view of the often strong currents in rivers, it would be difficult to interpret ks as a vertical settling velocity divided by the mean depth of the river bed as done in Eq. 23-16. In fact, ks should be understood as an empirical coefficient describing the specific first-order removal rate of suspended particles from the river. 

To bridge the gap between molecular processes and empirical coefficients and between laboratory determinations of input data and an engineering approach to predictions, we want to develop the above fundamental equations in terms of the kinetic theory of gases and reaction rate theory. There are three principal candidates for the rate-controlling... 

The disadvantage is that there is no reliable correlation of the single-phase pressure drop in almost all cases it is possible to use an equation of Ergun s type, but the empirical coefficients of this correlation have to be determined experimentally a priori calculation can be very inaccurate. 

We consider that the cascade occurs at equal intervals on the logarithmic scale of the quantity A. We replace the difference equation by a differential one. In doing so, we introduce an empirical coefficient, a which accounts for the fact that, in heat transfer in a given direction, only the component of the turbulent velocity in this direction takes part. Finally we propose the equation (omitting the overbar in A)... 

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