Abstract: A bioelectrical impedance measuring system that measures and indicates the impedance of a biological subject, such as one or more human extremities. The system measures and indicates a basal impedance value of the measured subject, and also indicates short temporal variations in the basal value. In the system an excitation signal, derived from an electrical signal source, is coupled to the subject by excitation electrodes and a resulting subject output signal is sensed by receiver electrodes. The subject output signal is electronically subtracted from a reference signal derived from the signal source, and the resulting signal is used to drive a display unit. The system includes a null detector connected to the display unit input, and an automatic gain control unit responsive thereto, connected in the subject output signal path to automatically maintain the system in a nulled condition.

Abstract: A differential pressure transmitter of the sensing diaphragm type is disclosed having low side overrange protection in which the central hub of the sensing diaphragm is releasably biased against the free end of the resilient spring in the transmitter body. A valving mechanism is provided so that under conditions of low side overrange, after the sensing diaphragm has separated from the spring, the valving mechanism provides a chamber of nonresilient body walls behind the sensing diaphragm filled with trapped fill fluid so that the sensing diaphragm is not distorted beyond its elastic limit by the high negative differential pressure.

Abstract: Detection of exhaustion of sodium form water softeners is accomplished by subjecting sample of the outflow from a water softener to reverse osmosis in order to separate monovalent (sodium) and divalent (hardness or magnesium and calcium) ions differentially from the outflow and measuring conductivity before and after the reverse osmosis. The two conductivities are compared in a ratiometer or differential device. After the softener becomes exhausted the divalent ion concentration in the outflow increases. Consequently the conductivity ratio changes to indicate that the water softener has become exhausted.

Abstract: A semiconductor material is doped or alloyed under vacuum with an impurity by thermal decomposition and by sedimentation resulting from centrifugal force. The doping material is alternatively applied by evaporation before being subjected to centrifugal force and may be heated up to the melting point before completion of the centrifugal action. A centrifuge is provided having a thermal insulating layer between the outer wall of a rotor and a support for basic semiconductor material to be doped. The doping impurity material to be evaporated onto the basic solid state material is placed in the center of the centrifuge rotor.

Abstract: An electrode housing for a fluid conductivity cell contains a chamber in which electrodes are securely positioned, the walls of the housing being electrically nonconducting and having at least one chamber duct penetrating the walls of the housing for the ingress and egress of fluid to be measured. The chamber duct is located relative to the electrodes such that it is substantially coincident with at least a portion of a line of equipotential established at the inside surface of the chamber in response to a voltage applied to the electrodes. The chamber duct is a size and shape to provide a negligible voltage drop across any dimension thereby substantially confining a conduction of current between the electrodes to the chamber of the electrode housing.

Abstract: To compensate for the nonspecific absorption in an atomic absorption spectral photometer an auxiliary illuminating source is provided in addition to the principal illuminating source. The need for moving parts and mirrors is obviated by mounting the principal and auxiliary radiation sources in fixed positions along a common ray path. The auxiliary source is constructed so that it is optically transparent and mounted adjacent the optical input with the radiation concentrated in an emission center common to both sources coinciding with the emission center of the auxiliary source. The sources are pulsed so that they are energized alternately.

Abstract: A method of analyzing nitric oxide (NO) in a gas stream containing nitrogen dioxide (NO.sub.2) and a scrubber apparatus for selectively removing nitrogen dioxide from a gas stream containing nitric oxide. The scrubber apparatus comprises a container having an inlet port for the gas stream and an outlet port. The scrubber material in the container includes silver carbonate whereby the scrubber has an efficiency of at least about 99% and a capacity of about 11.5 parts per million hours of 99% nitrogen dioxide removal per gram of silver carbonate. The method involves passing the gas stream through a scrubber material containing silver carbonate so as to remove nitrogen dioxide from the gas stream while passing the nitric oxide unattenuated and thereafter conveying the gas stream from the scrubber material to an analyzer for nitric oxide. The gas stream is analyzed with the analyzer to determine the nitric oxide concentration therein.