Apparent specific heat capacity

The view that the clay surface perturbs water molecules at distances well in excess of 10 A has been largely based on measurements of thermodynamic properties of the adsorbed water as a function of the water content of the clay-water mixture. There is an extensive literature on this subject which has been summarized by Low (6.). The properties examined are, among others, the apparent specific heat capacity, the partial specific volume, and the apparent specific expansibility (6.). These measurements were made on samples prepared by mixing predetermined amounts of water and smectite to achieve the desired number of adsorbed water layers. The number of water layers adsorbed on the clay is derived from the amount of water added to the clay and the surface area of the clay. 

An alternative approach was used that incorporated the apparent specific heat capacity (i.e. the latent heat is included in the specific heat term) as ... 

Figure 22.7. Comparison of model (thin line) and experimental (thick line) temperatures for the cooling of tempered chocolate at a nominal rate of 2 C/min. The model uses apparent specific heat capacity data taken from DSC measurements at a cooling rate of 2 C/min (Tewkesbury, Stapley and Fryer 2000).

Figure 4 gives the apparent specific heat capacity [< >(Cpj)] of lysozyme... 

Fig. 4. The apparent specific heat capacity of lysozyme from 0 to 0.45 g of water per gram of protein. The curve is calculated. The heat capacity measurements were made with lyophilized powders of lysozyme, appropriately hydrated, except for the four measurements indicated by the square symbols, for which the sample was a film formed by slowly drying a concentrated solution of lysozyme. From Yang and Rupley (1979).

Fig. 38. Comparison of heat capacity and spectroscopic properties. Effect of hydration on lysozyme time-average properties. (Curve a) Carboxylate absorbance (1580 cm" ) (curve b) amide I shift ( 1660 cm" ) (curve c) OD stretching frequency (—2570 cm ) (curve d) apparent specific heat capacity (curve e) diamagnetic susceptibility. From Rupley elal. (1983).

Figure 2. Apparent specific heat capacity of lysozyme from 0 to 0.45 g of water...

Apparent specific heat capacity = c Larger Decreases... 

Figure 4.24. Apparent specific heat capacity of a poly(oligoamide-12- //-oligooxytetramethylene) copolymer. Copolymer is analysed with a quantitative baseline based on heat capacity.

In the next step, the empty pan function is subtracted from the sample function. The result is the corrected heat flow rate into the sample. This function is divided by the sample mass and the heating rate (10 Kmin ) to calculate the (apparent) specific heat capacity function. The result is plotted in Figure 9.8 as a function of temperature. 

FIG. 7 Apparent specific heat capacity of AOT (Caot) in the micellar phase as a function... 

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