Abstract: A universal calibration method and apparatus for nondestructive real time determination of moisture content in particulate or granular materials by radio-frequency sensors is described which is bulk-density and material-independent and remains valid across instruments of different designs.

Abstract: A method for simultaneously and independently measuring moisture content and bulk density of particulate materials using radio-frequency measurements allowing for on-line, real-time monitoring and control. Moisture and density are determined by measurements of complex permittivities. This method is based on the use of the dielectric properties of the materials for density and water content determination.

Abstract: A method for nondestructively determining the mass of arbitrarily shaped dielectric objects is disclosed. The object is inserted into a microwave resonant cavity coupled to a microwave radiation source and a measuring circuit. Measurements of shift of resonant frequency and change in the transmission coefficient due to the presence of the object in the cavity are made. The mass is determined from using this information. The process is particularly useful for determining the mass of articles that are too hot or too cold or too fragile to handle and for articles that are irregular or variable in shape.

Abstract: A process for nondestructively determining the moisture content of single articles such as single grain kernels, seeds, nuts, fruits, or other biological or agricultural products. The article is inserted into a microwave resonant cavity coupled to a microwave radiation source and a measuring circuit. Measurements of the energy dissipated in the sample and the shift in frequency (or wavelength) due to the presence of the article in the cavity are made at each of two orientations differing by about 90 degrees with respect to the maximum electric field vector. The moisture content is subsequently determined from the ratio of the averaged values of the energy dissipated to the shift in frequency. The process is particularly useful for determining the moisture content of articles of irregular or variable shape.