Abstract: A method and apparatus for determining water activity levels of samples by spectral analysis. The method and apparatus facilitate much faster water activity level measurement than prior methods and apparatus. The method may include calibrating a spectral analyzer by correlating samples of known water activity to certain spectral features. A calibrated apparatus according to principles of the present invention may very quickly correlate spectral features of a sample of interest with a water activity level to a high degree of accuracy.

Abstract: A grain measuring and weighing device including an entrance chamber, a constant volume chamber, and a weigh chamber. A plurality of gates controllably move between open and closed positions to allow a known volume of grain to flow between chambers. The weighing and measuring system includes a means for compensating and eliminating forces external to the grain harvester, such as the various forces due to sloping surfaces and rough terrain over which the grain harvester moves, that would otherwise adversely affect the grain yield data. In one embodiment, an accelerometer is use to measure such external forces. In another embodiment, a reference weight is used to measure the external forces.

Abstract: A multi-level probe for sonic range measurements utilizes a plurality of parallel reflectors that each include an opening arranged coaxially about a beam of ultrasonic energy transmitted along a reference axis from an associated transducer. The opening in each reflector permits most of the sonic energy to pass to a subsequent reflective surface, while the periphery about the opening provides echo signals for determining physical conditions in the environment through which the sonic energy has passed. A novel system is used for determining physical conditions that are a function of time differences between signals from different reflectors, calculated with a highly efficient digital signal processing algorithm.