Microwave techniques for the measurement of moisture content are very well known. Their use with particulate solids is, however, difficult unless the bulk density of the material is either stabilised or monitored. This limitation of the method can be overcome by using instruments which measure two microwave parameters and, in addition, some further computation can yield not only density compensation but also density determination. To demonstrate the wide applicability of this method, dielectric data are taken from the literature for a variety of different particulate solids, and the parameters relevant to industrial microwave measurements extracted.
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