Relative humidity . See

We indicated in Chapter 8 (Section 8.2E) that the turbulent air immediately outside the air boundary layer adjacent to a leaf contains 0.48 mol water m-3 when it is at 20° C and 50% relative humidity (see Fig. 8-7). Our calculation indicates that could drop by 0.21 mol m-3, which means from 0.48 mol m-3 to 0.27 mol m-3 (28% relative humidity at 20°C), as we move... 

An aqueous gel (1 liter per min) is spray dried at 25°C in a counter-current spray dryer. The droplets produced by atomization are 50 pm in diameter and remain that size throughout drying. If the drying rate is limited by mass transfer in the boimdary layer, what height of the spray dryer of cross-sectional area 1 m is required if the drying air (100 liter per min) enters at 150°C and = 0% relative humidity. See problem 3 for the data. 

Moisture content hydroxypropyl cellulose absorbs moisture from the atmosphere the amount of water absorbed depends upon the initial moisture content and the temperature and relative humidity of the surrounding air. Typical equilibrium moisture content values at 25°C are 4% w/w at 50% relative humidity and 12% w/w at 84% relative humidity. See Table III. See also Figure I. 

Moisture content povidone is very hygroscopic, significant amounts of moisture being absorbed at low relative humidities. See Figures 1 and 2. 

It was mentioned in Chapter 4 that aerosol particles scatter and absorb solar radiation. These processes depend upon the concentration, size distribution, form, refractive index and absorption coefficient of the particles, as well as upon the wavelength of the radiation. In the case of water-soluble particles the extinction is also controlled by relative humidity (see Section 4.5). The energy absorbed by particles leads to an increase of temperature, while backscattering produces an energy loss for the system. Sines this energy loss may be characterized by the albedo, it is proposed to examine first the relation between albedo and temperature in surface air. 

The ambient air will be considered at 10°C with 70% relative humidity (see Table 31.30). 

As one might anticipate, hair fiber stiffness also varies with relative humidity it decreases with increasing relative humidity (see Figure 8-23). We might conclude that hair fiber stiffness generally parallels fiber-stretching properties with respect to treatments. This conclusion is probably correct however, further empirical tests should be made before this conclusion becomes accepted. 

Fatigue crack growth rates at room temperature, tested in latx>ra-tory air at 50 to 70% relative humidity. See table for treatments and yield strengths. 

A few typical equilibrium-moisture relationships are shown in Fig. 12.1, where the moisture in each case is water. Here the equilibrium partial pressure p of the water vapor in the gas stream has been divided by the vapor pressure of pure water p to give the relative saturation, or relative humidity (see Chap. 7), of the gas, since the curves are then applicable over a modest range of temperatures instead of being useful for one temperature only. Consider the curve for wood. If the wood contained initially a very high moisture content, say 0.35 kg water/kg dry solid, and were exposed to a continuous supply of air of 0.6 relative humidity, the wood would lose moisture by evaporation until its equilibrium concentration corresponding to point A on the curve was eventually reached. Further exposure to this air, for even indefinitely long periods, would not bring about additional loss of moisture from the solid. The moisture content could be reduced further, however, by exposure of the solid to air of lower... 

Moisture. The effect of atmospheric moisture becomes pronounced above 50 percent relative humidity (see Fig. 2.29). Below 50 percent, the surface water does not form a coherent monolayer therefore, it does not provide an electrical path for conduction. Treating the glass with water-repellent materials such as silicones will lessen the effect of humidity on surface resistivity. 

These polymers are less cohesive and thus have a glass transition temperature and a melting temperature lower than those of PA-6 and PA-6,6. Their mechanical characteristics are also slightly weaker but depend much less on the relative humidity (see Table 15.5). These polymers are not utilized for textile applications. They are used for manufacture of monofilaments (fishing nets, cords for musical instruments, ropes) and also as technical polymers for the surface coating and the molding of various objects that are required to resist moisture. 

Once the print is complete, remove the slides and incubate them for 1 h at 70 % relative humidity (see Note 10). 

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