Water vapor desorption generation

Tt is generally recognized that water plays an important role in main-taining skin in a healthy state with desirable mechanical properties (I). This work describes a technique for generating information on the state of water in the stratum corneum in vitro, with particular emphasis on the mobility of water in the corneum matrix and the eflEect of stratum corneum components on the characteristics of water diffusion. The characteristics of water diffusion in the stratum corneum are derived from sorption and desorption kinetics by using a gravimetric technique which allows determination of the amount of water vapor sorbed or desorbed continuously from an air stream of any given relative humidity. 

In contrast with the above situation, chamber pressure becomes an independent programmable variable when a calibrated leak, or successive leaks of different pressure levels, is performed during the lyophilization. A usual way to generate a calibrated leak is to repeatedly inject nitrogen into the chamber so as to maintain the total pressure within a narrow range of values, this independent of the course of ice sublimation or water desorption. Another method for generating a constant pressure inside the chamber is to open and close repeatedly the valve between the condenser and the vacuum pumps, so as to maintain the water vapor pressure within predefined limits. 

The moisture absorption/desorption capability of the solid fiber depends on the relative humidity of the enclosed air in the microclimate around the fiber and the type of fiber material. When fibers absorb moisture, heat is generated and released. Consequently, the temperature of fiber will rise and thus results in an increase of dry heat flow and a decrease in latent heat flow across the fabric [11]. The absorbed/desorbed moisture of fibers and the water vapor in the enclosed microclimate in textiles compose the water content of the textile material, which can originate from the... 

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