Moisture load reduction

Reduction of moisture load Limit construction moisture Initially dry materials... 

Table 4.5 Reduction of moisture load by building design and operation after Lstiburek and Carmody [40] and Ten Wolde and Rose [46] ...

Humidity can be a problem. Whereas it was shown (284) that 33% RH was best for spore inactivation, and that at least 30% RH was needed for effective sterilisation (285), dried spores are difficult to kill, and the spore substrate material and wrappings compete with the spore for the available moisture (286). Therefore, the relative humidity is adjusted to 50—70% to provide sufficient moisture for the spores to equiUbrate. The exposure time depends upon the gas mixture, the concentration of ethylene oxide, the load to be sterilised, the level of contamination, and the spore reduction assurance requited. It may be anywhere from 4—24 hours. In a mn, cycles of pre-conditioning and humidification, gassing, exposure, evacuation, and air washing (Fig. 9) are automatically controlled. 

The stationary furnace used for reduction has three temperature zones through which the boats loaded with tungsten tri oxide move before the oxide is converted to the metal. The loaded boats pass into the furnace countercurrent to the movement of hydrogen gas. Thus the gas in the highest temperature zone has the minimum moisture content, and the moisture content becomes maximum when the gas passes through the lowest temperature zone. This arrangement ensures the highest possible reduction efficiency. 

Extensive work has been carried out in the US regarding the use of soil filters for odour reduction. (6) It was shown that the filter performance depended on filter loading, type of soil, soil moisture, temperature and concentration of odourous components. The US study also concluded that both chemical and biological processes were responsible for the odour reduction. 

Choosing carbon black as a filler for fibers has many implications. Figure 19.18 shows the effect of carbon black loading on viscosity in PET. Viscosity depends on the type of carbon black. A reduction of 50% viscosity can be attained at the same carbon black concentration simply by change to another grade of carbon black. Moisture absorption, which affects the drying time, can be substantially reduced (by about 50%) by the selection of the appropriate carbon black." Tiber color and tone are affected by the carbon black type and by the method of its dispersion. 

The compressive properties of a composite under aU loading conditions are strongly affected by moisture absorption because of the reduction in shear properties of the matrix polymer. The design of artefacts with polymer matrix composites needs to reflect the limitations of these materials in compression, especially in service where environmental conditioning is likely. 

Neither a model of creep, nor the mechanism of this process is known as well. Obviously, the creep relates to the properties of cement gel and the presence of adsorbed water. The creep growth with moisture content in a paste, while the dried samples do not show this effect [127]. However, this latter statement is not quite sure perhaps only a substantial reduction of creep occurs [128]. The hypotheses assume the squeezing of water from the paste under load. 

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