Hygrometry

Electrolytic hygrometry in which the quantity of electricity required to electrolyse water absorbed from the atmosphere on to a thin film of desiccant is measured. 

Piezo-electric hygrometry employing a quartz crystal with a hygroscopic coating in which moisture is alternately absorbed from a wet-gas and desorbed in a dry-gas stream the dynamics is a function of the gas humidity. 

Figure 4.29. (a) EVOH Examples of oxygen permeability versus hygrometry (%) for low and high VOH content (b) EVOH ... 

Examples of oxygen permeability versus crystallinity for 0 and 100% hygrometry (c). EVOH Example of oxygen permeabilities versus temperatures (°C)... 

Figure 4.58. (a) Neat PA examples of resistivity (ohm.cm) versus relative hygrometry (%) (b) Neat PA examples of... 

Figure 4.62(a) displays examples of resistivity versus hygrometry for two grades of PA 12. Figure 4.62(b) displays examples of resistivity versus temperature for one grade of PA 12. 

Zeno W. Wicks, Jr., Consultant, Las Cruces, NM, Drying Oils Pieter R, Wiederhold. General Eastern Instruments Corporation. Water-town. MA, Hygrometry and Psychrometry Paul Wight, Seneca Specialties. Manchester, U.K. Xanthene Dyes E. Williams, Cobalt Information Centre, Londtm. UK, Cobait Richard A Wilsak, Amoco Chemical Company. Naperville. IL Butylenes Richard A. Wilson, International Flavors Fragrances. Union Beach, NJ. http //www.ifT.coni/. Benzyl Alcohol and /j-Phenethyl Alcohol Oils, Essential... 

Michele Instruments Ltd. Technical Bulletin (1988). Advanced industrial hygrometry. 

Thus, in the domain of validity of Henry s law, the equilibrium concentration is proportional to the relative hygrometry (at a given temperature). 

Here, the best way to accelerate aging is to decrease the sample thickness (when possible). Except in very highly hydrophilic materials, D is independent of the relative hygrometry or water activity, but is an increasing function of temperature ... 

Baker, H. and Kligman, A.M., Measurement of transepidermal water loss by electrical hygrometry. Instrumentation and responses of physical and chemical insults. Arch. Dermatol. 1967 96 441. 

The water uptake of HA is represented in Figure 10.2 as a function of the hygrometry p/po of the surrounding atmosphere. In this figure, the number of H2O molecules per disaccharide that become embedded in HA following the four hydration mechanisms H (i = 1 ), defined below, are shown. The number of H2O molecules already present in the dried state (4-5 per disaccharide unit) is included into the total number of embedded water molecules... 

Figure 10.2 Number Bjj q of water molecules per disaccharide in HA, as a function of the hygrometry p/po. Details at low hygrometry, where only mechanism //, is active, are represented in the enlarged upper left part. Numbers of molecules embedded following mechanism //, are represented by circles, those following mechanism //j by X, those following mechanism by stars and those following mechanism by diamonds, (empty squares) is the total number of embedded HjO molecules, obtained from IR spectra and equal to the addition of the numbers of molecules entered following all mechanisms to plus the number of residual HjO molecules in the dried membrane (eq. (11.8)). Full squares joined by straight lines represent this total number of HjO molecules, as measured by thermogravimetry.

Figure 10.5 Development of the H-bond network in a sulfonated polyimide (homo)polymer made of chains of aromatic and polyaromatic substituted cycles. Three repeat units of a chain are represented. Structure of the dried membrane in the upper drawing, of the membrane in equilibrium with an atmosphere with hygrometry 15% (middle page drawing) and 65% (lower drawing).

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