Hydration degree

Change in Composition of Surface Film with Treatment. Since trivalent chromium hydroxide can be generally expressed as Cr203 nH20, the composition of the outermost surface layer is assumed to be expressed by "Equation 2" and the hydration degree n and covering rate a of chromium... 

The covering rate a and hydration degree n of chromium hydroxide and the polar group ratio [C ](>o / ]total shown in Fig. 8. It is found... 

Figure 9. Effect of the polar group ratio of oil and the hydration degree of chromium oxide on lacquer adhesion.

A high correlation coefficient ( r = 0.903, 99 percent confidence level) was found between Y c and polar group concentration ( COO) and relatively high correlation coefficients were obtained between Yc and the metallic elements (Cr and Ni), but carbon (main component of oil), oxygen, hydration degree (n) and covering rate W showed low correlation coefficient. In Fig. 11, Yc versus the polar group concentration is presented. 

It is of interest to note that hydration degree (n) does not directly contribute to the wettability, suggesting that it affects the bond strength formed during the cure of UVC lacquer. 

Kruk, A. 1979. Relationship between casein hydration degree and thermal stability of milk. Acta Alimentaria Polonica 5, 147-156. 

This reaction is often reported to proceed easily at room temperature6,8,l4,3° 46 for fully hydroxylated silica, although other temperatures have also been used for deuteration.47,48 However, some comments on the deuteration process used and the initial silica hydration degree have to be considered. 

Photophysical and photochemical behavior of the polyacene molecules such as pyrene, anthracene, perylene adsorbed in the cages of X and Y zeolites depend on the cation and hydration degree of zeolites [1-3]. 

Effect of residual water on the hydrate degree and the remaining enzymatic activity of freeze-dried LDH. 

Volumetric data can be essential in the thermodynamic treatment of the "polymer-solvent" interaction process. The lack of them for many important fibrous proteins is due to the difficulty of measuring the density, at controlled temperature and hydration degree, for these systems. As far as elastin is concerned, it has been reported that when completely hydrated this protein has a negative and very large coefficient of thermal expansion (15), a result which has been interpreted as evidence of a hydrophobic character of the protein (16). 

Density measurements are extremely Important in industry, because a large amount of information can be obtained about a material with a reasonably simple measurement. By measuring the density of liquids, we can determine how much electrical charge is in your car battery, at what temperature your radiator will freeze, the salt content of a pickling brine, the alcohol content of a brandy, and certain diseases from urine samples. The densities of solids can tell us the hydration degree and porosity of Portland cement, the cotton-polyester blend in a fabric, the velocity of detonation of... 

It is possible to make a micellar matrix more effective and more rigid by the replacement of water by water-organic solvent mixtures [42] (Fig. 7). As seen from Fig. 7, replacement of water with glycerol in the inner cavity of reverse micelles leads to a shift in dependency profiles, (n o) to the area of lower values of hydration degree. 

Fig. 3.16 CjS hydration in the static and stirred CjS paste (according to [28]) (a) Ca +ions concentration vs. time, (b) CjS hydration degree (w/c = 0.3, temperature 20°C)...

Belite hydration occurs analogously but this is significantly shifted in time after 28 days the degree of hydration is approximately 25 %, this corresponds to the hydration degree of alite after 1-1.5 day reaction with water. 

Sodium and potassium carbonates accelerate strongly the CjS hydration. The induction period is shortened and on the calorimetric curve the additional peaks of unknown origin appear (Fig. 4.47) [139]. The effect of K2CO3 is proportional to the concentration with which the hydration degree and non-evaporable water are increasing [139]. 

The hydration of cement paste in water vapour at atmospherie pressure and temperatures up to 100 °C causes a significant acceleration of the proeess. Odler and Skalny [191] found the hydration degree of CjS after 6 h at temperature 50,75 and 100 °C as 23, 36 and 48% respectively. At 100 °C the hydration of C3S was eom-pleted after 3 days. 

The calculation of porosity from the water vapour adsorption isotherm leads to the higher value. Obviously, the porosity becomes higher with increasing w/c ratio because the hydration products cannot fill the rising volume of pores (Fig. 5.30). However, the porosity is substantially lower when nitrogen is applied as an adsorbate. The hydraulic radius of pores, determined from the water vapour isotherm, decreases also with the rise of hydration degree. The ratio of micropores is also increasing [54] with the time of hydration. When the samples are dried only at 11 % RH (over the LiCl H O saturated solution), the porosities from water vapour determination are close to these obtained with helium or methanol [62]. 

In the paste with low hydration degree the capillary effect is of special importance. The capillary pressure leads to the collapse of pores with diameter in the range from 4 to 10 nm, associated with the specific surface decrease, as measured by nitrogen adsorption. 

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