Fractional moisture content, defined

The moisture content of wood is usually calculated in terms of its dry weight. The fractional moisture content m is defined as the ratio of the mass W of removable water to the dry mass W of the wood (Equation 1). 

Cake Dryness In dewatering, usually the cake needs to be as diy as possible. Cake diyness is commonly measured by the solids fraction by weight W or by volume ,. The moisture content is measured by the complement of W or ,. The volume fraction of the pores and void in the wet cake is measured by the cake porosity (= 1 — ,) whereas the volume fraction of the liquid in the pores of the cake is measured by the saturation S. For welf-defined solids in the cake with sohd density (bone diy) p, and hquid density Pl, and given that the cake volume... 

Thus for both an ideal system and for high moisfure confenfs, wafer acfivify is effecfively equal fo the mole fraction of wafer in fhe liquid phase wifhin fhe food. There are difficulfies in using equafion 4.5 because acfivify coefficients are complex functions of both temperature and moisture content and are not readily determined. Now, relative humidity is defined by... 

The fiber-saturation point is defined as the moisture content at which the cell cavities are empty of liquid water but the cell walls are still saturated with bound water (6). The fiber-saturation point is designated as mf (fraction of dry mass) or Mf (percent of dry mass). 

The water in coal is bound in different forms to its constituents. It can be divided into three types (1) Free moisture, also referred to as external moisture, superficial moisture, or the primary moisture fraction, which is present in large cracks and capillaries. Water bound in this way retains its normal physical properties. (2) Inherent moisture, also referred to as internal moisture or the secondary moisture fraction, whose vapor pressure is lower, since it is absorbed within the pore structure of the coal. (3) Water of constitution, which is mainly combined with mineral matter normally present in coal. This water is generally driven off only at temperatures higher than those normally used for the determination of moisture content. Standard methods do not make use of these terms and define (1) the total moisture content of a coal and (2) the moisture content of the coal analysis sample. Total moisture determination must be made over the sample as received in the laboratory, in an air-proof recipient. The determination consists in drying in an oven at 105 °C till constant weight. Its value is of huge interest both in international and domestic coal trade (ISO 589, ASTM D3173). 

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