Abstract: Apparatus and methods for measuring the properties of a material by employing a driven electrode, a sensing electrode and a shunting electrode. The shunting electrode is disposed in proximity to the driven and sensing electrodes and functions to increase the sensitivity of electrical measurements made between the driven and sensing electrodes by influencing the coupling of the imposed electric field to the sensing electrode to a degree related to the properties of the material under test.

Abstract: A method of determining the moisture content of a material in which the material is caused to flow continually through a sensor region, the spatially averaged temperature of the material being continually determined independently of the dynamic thermal response of the material. The loss and capacitance of the sensor is also continually determined, the moisture content of the material than being determined in response to the spatially averaged temperature and the loss and capacitance determinations independently of changes in the packing density of the material as it continually flows through the sensor region.

Abstract: An ohmically or electrothermally controlled valve gate for injection molding apparatus comprises three concentrically located tubes in intimate contact with each other. The innermost tube is an electrode and also serves as the passage for flowing molding material. The outermost of the three tubes is also an electrode. The intermediate tube is a resistive heating element comprising a mixture of at least two highly compacted powders. One powder is an electrical conductor, while the other powder, which serves as a binder for the first powder, is an electrical insulator but a good thermal conductor. Current flow between the electrodes occurs at points of contact between adjacent particles of the conductive powder. Thus, the electrical resistance and therefore the generation of heat is controlled by the composition and quantity of binder in the heating element. The generated heat is conducted through the inner electrode tube to the flowing plastic to melt the plastic and "open" the gate.