Relative humidity, relationships

There is virtually an identical quantitative binding of water to wool and hair as a function of relative humidity [28,29] therefore, we conclude a similar stress/strain relative humidity relationship (see Table 8-2). 

The electrical resistances of wool and human hair have been shown to be very similar at 85% RH (see Table 8-23), and their resistances are similar from 52 to 85% RH [131], Their moisture binding-relative humidity relationships from 0 to 100% RH are virtually identical (see Table 8-16), so their resistance-relative humidity relationships from 0 to 100% RH must also be very similar. The resistance of wool hber has been shown to vary by a factor of approximately 10 from 10 to 90% RH and by a much larger factor from 0 to 100% RH [136]. 

Equilibrium Moisture Content-Equilibrium Relative Humidity Relationships Used to Analyze Sorption and Desorption Isotherms of Grains and Oilseeds... 

Fig. 1. Relationship between the moisture content of wood (% of dry wood) and relative humidity at different temperatures.

Fig. 3. Relationship of moisture content and relative humidity to specific resistance of polymeric, fibrous materials.

Temperature Although ambient temperature would be expected to have an influence on the rate of rusting, its effect is not clearly defined despite the efforts of workers to establish a relationship . It has an effect on relative humidity and consequently an indirect effect on corrosion. However, fluctuations in temperature may be more important than average temperatures because they influence condensation and the rate of drying of moisture in contact with steel. 

The relationship between the percentage humidity of a gas and the percentage relative humidity may be derived as follows ... 

Coplen, T.B. (2011). Guidelines and recommended terms for expression of stableisotope-ratio and gas-ratio measurement results. Rapid Gommunications in Mass Spectrometry, 25, 2538-2560. DOl 10.1002/rcm.5129 Cormie, A.B., Luz, B., Schwarcz, H.P. (1994a). Relationship between the hydrogen and oxygen isotopes of deer bone and their use in the estimation of relative humidity. Geochimica et Cosmochimica Acta, 58, pp. 3439-49. 

Figure 2.4 shows the equilibrium relationships of biological materials between the water content and the water activity, at constant temperatures and pressures. These data were first published in 1971, but did not find much attention in the RM field until now. At equilibrium the water activity is related to the relative humidity cp of the surrounding atmosphere (Equation 2.3) where p is the equihbrium water vapor pressure exerted by the biological material and po the equilibriiun vapor pressure of pure water at the same temperature. 

The capacity for aerosols to take on moisture by hygroscopicity gives rise to a kinetic phenomenon of change in particle size as a function of residence time at a particular ambient relative humidity. This phenomenon can best be described in terms of the relationship between saturation ratio and particle size according to the following expression [9] ... 

Capillary forces increase in relationship to the relative humidity (RH) of the ambient air. At greater than 65% RH, fluid condenses in the space between adjacent particles. This leads to liquid bridges causing attractive forces due to the surface tension of the water. 

Another example of pressure-induced polymorphism is seen in the case of amiloride hydrochloride, where ball-milling Form-B causes a solid-state phase transformation into Form-A [43]. These workers deduced the phase relationship between two different pressure-induced polymorphs of the dihydrate, as well as the alternative route to one of those dihydrate forms that used the anhydrous form as the source material and effected the phase transformation through storage at high degrees of relative humidity storage. 

Figure 5.5 Relationship between accessibility and moisture uptake at different relative humidities.

If the definition of TOW established by ISO is used (TOW-ISO), a linear relationship between time and TOW is obtained, in spite of the different possible changes in corrosion rate caused by changes in the nature of TOW. It has to be remarked that it is not the same effect on corrosion rate caused by a heavy rain than dew, fog or water adsorption, so for the same interval of relative humidity (80-100%), notable changes in nature of TOW-ISO and consequently in corrosion rate could take place. 

Relative humidity RH) is related to Henry s law constant through the relationship implied in equation (E8.1.3), or... 

While many sets of data appear to follow Eq. (VV) relatively well, with slopes of mr 1 as predicted, deviations in the values of mT and br are often observed. There are a number of reasons for such deviations (e.g., see Pankow and Bidleman, 1992). For example, changes in temperature, concentrations of SOC, and relative humidity during sampling, nonattainment of equilibrium, and sampling artifacts can all lead to deviations from the predicted, equilibrium relationship. In addition, if (A7/d AHvap) in Eq. (UU) is not constant along the series, relationship (VV) will not hold because the value of ft. is changing. 

Perhaps the most direct experimental means of examining the relationship between emissions and air quality is to simulate atmospheric conditions using large chambers. Measured concentrations of the primary pollutants are injected into these environmental (or smog) chambers, as they are called. These are then irradiated with sunlight or lamps used to mimic the sun, and the time-concentration profiles of the primary pollutants as well as the resulting secondary pollutants are measured. The primary pollutant concentrations as well as temperature, relative humidity, and so on can be systematically varied to establish the relationship between emissions and air quality, free from the complexities of continuously injected pollutant emissions and meteorology, both of which complicate the interpretation of ambient air data. 

Clearly, such experiments can be used to examine the relationship between primary emissions and the formation of a host of secondary pollutants. For example, runs can be carried out at varying initial concentrations of hydrocarbon and NO, and the effects on the formation of secondary pollutants such as 03 studied. The reactivity of various hydrocarbons can be examined by studying them singly or in combination. In addition, such parameters as temperature, relative humidity and total pressure, presence of copollutants, and spectral distribution of the light source can be systematically varied. 

The acid number determinations were made immediately after refinement of the oil and were continued at every biological test period for 325 days. The oil was applied at 100% concentration to the point of runoff on immature bean and corn plants in the greenhouse. The temperature at which the plants were grown for the duration of each test was 80 F., and the relative humidity was approximately 85%. Phytotoxicity was determined on the second, seventh, and fourteenth day after the plants were sprayed. Figure 1 demonstrates the relationship obtained in these tests between acid number and per cent of plant injury. 

The design of large natural draft cooling towers and analysis of their performance are complicated by the effects of variations in ambient air humidity. Often the effluent air from the tower is assumed to be at 100% relative humidity, to simplify calculations for design parameters. This study avoids the simplification, and proposes a procedure for determining the major design parameters for a natural draft tower. The theoretical and empirical relationships applicable to heat balance, heat transfer and transport, and tower draft and air resistance are given. 13 refs, cited. 

To obtain water vapor concentration, output signal intensity by TDLAS is calibrated under a well-controlled environment in variation of relative humidity and surrounding temperature. Figure 10 shows a relationship between water vapor concentration and output signal intensity detected by TDLAS. It is shown that the... 

The Arrhenius relationship of the property degradation rates of uncoated silk over a range of temperatures was determined. A temperature of 150°C was found to be inappropriate for the accelerated thermal aging of silk because of the large effect on the extrapolated reaction rate at 20°C for tensile properties and also because of the amount and hue of color developed. In addition, changes in the relative humidity affected the degradation rate of tensile properties and yellowing only above a level of 50%. 

Table I shows the overall variation in the weights when the simulated-flood procedure was applied to similar pairs of identical books over an 8-mo period. The simulated flood was applied to these books as if they were loosely packed on the shelf—i.e., stored with minimum pressure applied to them. The relationship of each book s dry weight with the temperature and relative humidity of the room appears to have been comparable. The variability of the wetting action of both types of books is also similar however, the variances (the standard deviation squared) associated with the weights of the drained books are significantly different (statistical significance reported at the 95% confidence level unless otherwise noted) by use of an F-test (3). Since the handling of book pairs—i.e., one uncoated- and one coated-paper book—was the same in preparing samples for subsequent restoration studies, it might be concluded that drainage water from the books containing uncoated paper could be different from books with coated paper.

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