Saturation Coefficient

The absorption value of the burnt brick is a function of the calcium carbonate content in the raw material (within the normal brick-firing temperature range). This can be determined by thermal analysis. The different forming techniques alter this relationship. The saturation coefficient (standard CAN3 -A82.2-7 8) seems to be proportional to the amount of fine particles. It is emphasized that both absorption and saturation coefficients should be used in evaluating brick durability. 

The relationship between saturation coefficient and absorption reflects both the quality of the brick and the history of the brick, e.g., the starting raw material composition (clay minerals, quartz, calcite) and the firing condition (Fig. 24). These factors are conveniently identified and estimated by thermal techniques as already discussed. For each raw material, a rational durability index should be defined in terms of absorption and saturation coefficient. The appropriate index can be determined for quality control as the raw material changes. 

Length changes for a Canadian brick fired at various temperatures between 900 and 1100°C are shown in Fig. 25. All curves show a marked hysteresis and a length anomaly around 515 C (due to a-quartz - j8-quartz inversion). These parameters have a magnitude that is inversely proportional to the temperatures at which the specimens had originally been fired. 

The integral of the peak in the length change curve (at approximately 575°C) was shown to decrease systematically with firing temperature. This peak suggests the a-quartz to j8-quartz inversion. This inversion, unlike the quartz-tridymite conversion, is rapid and instantaneously reversible. A decrease in the anomaly with increased firing temperature is likely a result of a more complete conversion of quartz to tridymite above STO C. 

The DSC thermograms for brick specimens fired at various temperatures are given in Fig. 27. The heat liberated per unit mass of the specimen (calculated by arbitrarily defining the limits of the peak area) as a function of the firing temperature is indicated in the figure. An inverse proportionality is indicated. The results are dependent on clay composition and other characteristics and will be different for clays of different origin. However, the information can be of value in brick manufacture at an individual plant for quality control of the finished product and for the firing process. 

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Where p = specific growth rate, p max = maximum specific growth rate, X = microorganism concentration, S= growth limiting substrate concentration, and Ks= half saturation coefficient for hydrolysis. 

Respiration inhibition kinetics analysis (RIKA) involves the measurement of the effect of toxicants on the kinetics of biogenic substrate (e.g., butyric acid) removal by activated sludge microorganisms. The kinetic parameters studied are max> the maximum specific substrate removal rate (determined indirectly by measuring the maximum respiration rate), and Ks, the half-saturation coefficient [19]. The procedure consists of measuring with a respirometer the Monod kinetic parameters, Vinax and Ks, in the absence and in the presence of various concentrations of the inhibitory compound. 

Monod kinetics c T> - K+c = maximum growth rate (s ) h = half-saturation coefficient (g/m )... 

The Kq saturation coefficient of oxygen in the Monod-type kinetic equation is an important parameter, too. Its value strongly influences the specific growth rate, especially when the value of oxygen concentration is of the same order of magnitude as or lower than the Kq value. Its effect is illustrated in Fig. 10 in the presence of a dispersed organic phase, e = 0.2. The increasing value of Kq (Kq was chosen to be equal to 0.64 x 10 0.16 x 10 and 0.016 x 10 kg m ) has a... 

KjU is the half-saturation coefficient for each of the competing substrates, j, including 2 Example ... 

The permeability P of a gas through a polymer can be measured directly by determining the transport of mass through a membrane per unit time. The sorption constant S can be measured by placing a saturated sample into an environment, which allows the sample to desorb and measure the loss of weight. As shown in Fig. 2.63, it is common to plot the ratio of concentration of absorbed substance c t) to saturation coefficient Coo with respect to the root of time. 

Quinlan (8-10) has analyzed how changes in substrate concentration affect the optimum temperature of processes that saturate In substrate concentration according to a generic Mlchaells-Menten reaction mechanism. For such processes> the optimum temperature was shown to vary linearly with the logarithm of substrate concentration. This logarithmic relation results when both the maximum-velocity and half-saturation coefficients show Arrhenius temperature dependencies, with the latter s falling faster. Such dependencies are commonly seen In batch reactors (11-14), but not always (13.14). 

It s restricted to batch reactors and can t account for the Influence of mass Inflow and outflow In continuous reactors. It also can t explain why some maximum-velocity and half-saturation coefficients determined In continuous reactors tend to show non-Arrhenius temperature dependencies (15-19) and why others seem to vary with dilution rate (20.21). 

Half-Saturation Coefficient K. For batch culture, equation (lib) reduces to ... 

If s rises more rapidly with temperature than both numerator terms, then the batch-culture half-saturation coefficient should always decrease as temperature Increases. If s rises more rapidly than the numerator term dominant at low temperatures but more slowly than the term dominant at high temperatures, it should show a temperature minimum. If s rises more slowly than both numerator terms (Figure 3), it should always rise with temperature (Figure 4, d = 0)... 

The thermal sensitivities of the batch-culture half-saturation coefficients for several microbial processes (11-14) have been observed to resemble the linear portion of the d 0 curve in Figure 4. However, a few deviations from this pattern have been seen where the half-saturation coefficients showed either a negative slope or a maximum (13). Only the thermal maximum is inconsistent with equations (18) - (20). 

According to equation (21), the continuous-culture half-saturation coefficient equals the batch-culture half-saturation coefficient augmented by a term that increases linearly with dilution rate. However, the magnitude of this term should decrease exponentially with increasing temperature because of the factor 1/s. Thus, at low temperatures where the dilution term may dominate the batch-culture half-saturation coefficient, the continuous-culture half-saturation coefficient may decline with increasing temperature. 

It should grow with temperature only when the batch-culture half-saturation coefficient has a positive slope and dominates the dilution term. In this case, it may have a thermal minimum (Figure 4, d > 0). Moreover, for the range of dilution rates where the locus of minima (dashed line. Figure 4) parallels the... 

Figure 4. Theoretical thermal sensitivity of the half-saturation coefficient in batch (d = 0) and continuous (d > 0) culture with the parameter values specified in Figure 3. Dashed line, locus of thermal minima (O).

In continuous culture, the half-saturation coefficient has been observed to respond to rising temperatures by declining monotonically (15-17) and by showing a minimum (18,19). Both cases are consistent with the d > 0 curves in Figure 4. 

It may not be greater than the outer pressure. Usually bubble-point pressure of subsurface water is noticeably lower than the formation pressure - P. The saturation deficit is meastued by ratio P JP, which is called gas saturation coefficient. Addition of any volatile component to water at = P decreases the solubihty the other volatiles. Thus, the outer pressure restricts effective solubihty of any volatile nonpolar component. And the closer the P P value to 1, the stronger this effect. Oversaturation (excess of P JP over 1) caimot be substantial as in such a case water passes in the metastable state, at which nonpolar components must segregate out of the solution and form an independent nonpolar medium (undergroimd gas, crude oil or bitumen). 

Example 2.20. Due to an accident, a large amount of trichlorethilene entered the aeration zone (TCE (Cl2C=CHCl), which has molecular mass = 131.4 g-mole saturated vapour pressure = 57 mm Hg. Ground porosity in the aeration zone n = 30%, ground residual saturation coefficients with water K, = 0.33 and with TCE = 0.17. Determine max weight of trichlorethilene in the subsurface gas in 1 m of ground. 

Example 2.21. Oil product penetrated the aeration zone. Ground porosity n = 0.2, residual saturation coefficients is equal for water 0.5, for oil product 0.05. After this in the aeration zone air was discovered benzene at average concentration of 503 mkg-1 h Determine max total benzene content in 1 m of the aeration zone. 

Saturation Coefficient. The ratio of the amount of water taken up by a porous building material after it has been immersed in cold water for an arbitrary period (e.g. 24 h) to its water absorption, normally determined by boiling in water for 5 h the ratio is usually expressed as a decimal fraction, e.g. 0.85. A low... 

Schurecht Ratio. A term that has been used for saturation coefficient (q.v.) named from H. G. Schurecht (USA) who introduced this coefficient in his research on frost-resistance of terra cotta carried out at the National Bureau of Standards in 1926 but never published the term Schurecht Ratio was first applied by J. W. McBurney. Scleroscope. An instrument for determining the relative hardness of materials by a rebound method. 

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