Initial relative humidity

Fig. 7 Schematic representation of moisture transfer between solid components A and B with (a) headspaces isolated from one another and (b) headspaces allowed to equilibrate. Ra and Rb = initial relative humidities above A and B VA and VB = headspace volumes above A and B Rf and VT = final relative humidity and headspace volume above A and B. (From Ref. 95.)...

For the T300/Narmco 5208 system, the water concentrations within the bulk resin and at the void surface were obtained from measured solubility, weight fraction, and density data. The water concentration in the bulk resin is dependent only on the initial relative humidity under which the resin was equilibrated and is given by ... 

Initial Relative Humidity (RH) . This is the relative humidity at which the prepreg was equilibrated. 

The final diameter of a pure water void for different initial relative humidities of the resin is shown in Figure 6.8. The marked increase in the final void size illustrates the pronounced effect that initial relative humidity exposure has on the final void size. This behavior is described by Equation 6.28 in which CTO (which is fixed during the cure cycle and determines the driving force) increases with the square of the initial relative humidity exposure. Thus, increasing the initial relative humidity by a factor of 2 would result in a four-fold increase in C oo. This would in turn increase the driving force 4-fold when the other conditions of growth are kept identical and when Csat [Pg.197]

Figure 6.8 Effect of initial relative humidity exposure of the prepreg on the final void size in the laminate for the process conditions shown...

Figure 6.10 Void stability map for pure water void formation in epoxy matrixes. Note the significant effect of initial relative humidity exposure of the resin...

Figure 6.12 Profiles of typical resin pressures monitored by the laminate, tool, and bleeder transducers. The profiles of time-temperature and the corresponding time—Pmjn for 35% and 85% initial relative humidity exposure of the prepreg—are also shown. (Source From [25])...

For the results shown in Table 13, the model has included sufficient ammonia to bring about complete neutralization of the acid droplets in the air. As the initial relative humidity was high (99.5%), no hygroscopic growth of the particles occurred. Complete neutralization of 5 qin droplets would be expected in 3 s. The capacity of the ammonia present to neutralize all of the acid present should be contrasted with the extent of neutralization possible had the ammonia concentration been 50 pg m 3. 

Noting that the ratio on the LHS is equal to the initial relative humidity, and assuming that the temperature change is small enough so that T0 Td T, we get... 

Drying airhasthefollowing conditions Initial pressure= 101.3 kPa. Initial temperature (dry bulb) = 22°C. Initial relative humidity = 40%. Mass flow rate of fresh air = 42000 kg/h. 

Air Temperature Initial Relative Humidity Optimal Absolute Humidity Time of Drying until... 

Figure 37.2 shows the effect of reactor temperature on the solute concentration profile at the onset of precipitation within a droplet with 5 pm initial diameter for a given initial droplet number density, Nq, carrier gas flow rate, Q, and initial relative humidity, RHq, and initial solution concentration, Co [10]. The tubular reactor s inside diameter is 10 mm. The concentration profile inside the droplet depends on the operating conditions and reactor geometry. For reactor conditions of their study... 

Fig. 37.2 Solute concentration profile within the droplet for various wall temperatures for given initial droplet size dg, droplet number density Ng, carrier gas flow rate Q, initial relative humidity, RHo = 10%, and initial solute concentration Co = 2 M. (Reprinted from [10] with permission. Copyright 2009 of Taylor Francis)...

An increase in temperature will increase the equilibrium concentration of CO, if the initial relative humidity is zero. However, with the initial presence of water vapor in the fuel stream, an increase in temperature will decrease the equilibrium concentration of CO. This is beeause the partial pressure of water increases at higher temperatures, which drives Equation 16.8 to the left and results in a... 

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