Abstract: Apparatus for switching a fluid stream, either gaseous or liquid, between a first path and a second path is disclosed. A pair of enclosures are formed by two depressions in a first plate (each depression having an inlet and an outlet) and an elastomeric diaphragm covering the depressions. The diaphragm is held in place by a second plate having a first control inlet opposite one depression and a second control inlet opposite the other depression. A fluid to be switched is connected into the inlets of the first plate in common. By alternately applying a control fluid to one control inlet and then the other of the second plate, the fluid to be switched is switched from one outlet to the other by the diaphragm alternately being deformed into one depression and then the other by the control fluid so as to seal the inlet and outlet and, thereby, block the flow of fluid therethrough from the inlet to the outlet.

Abstract: An improved catalytic reactor system and method for removing interferents such as reactive hydrocarbons from the gas being sampled by gas component determination apparatus is disclosed. The sample from which the interferents are to be removed is blended with ozonized air and saturated to at least 15% with water vapor. The mixture is then passed through the catalytic reactor which, preferably, contains a mixture of platinum oxide mixed with sand and maintained at an operating temperature of 200.degree. to 280.degree. C. Additional catalytic mixtures which may be employed in the reactor are also disclosed. Methods of preventing the poisoning of catalytic reactors and rejuvenating poisoned catalytic reactors are also disclosed.

Abstract: A flat screen, electrically controlled, reflective display device is provided that utilizes a very thin layer of a positive dielectric anisotropy liquid crystalline material of the nematic type. The selected liquid crystal material is one whose optical phase shift transmission is a sensitive function of the electric field within it, allowing controlled optical transmission in conjunction with an optical circular polarizer. The nematic material is placed in a very thin layer in a flat-sided cell between transparent planar cell wall elements that accurately define the thickness of the nematic layer. Birefringence of the nematic liquid crystal is controlled by voltages applied to interleave arrays of alternate parallel electrodes coated on the inner surface of only one of the transparent cell elements. The invention includes novel means for holding constant and uniform the thickness of the thin nematic layer and for reducing undesired parallax and multiple image effects.

Abstract: The present invention discloses a method for determining the overall efficiency of an automotive exhaust system including a catalytic converter for removing unburned hydrocarbons and carbon monoxide from the exhaust gases. The carbon monoxide, hydrocarbon, and oxygen levels are monitored in the exhaust gases at the tailpipe. In a properly tuned engine, the base oxygen level is ascertained in order to establish the dilution effect of the air injection system on the exhaust gases which dictates the proper working curve on a disclosed Conversion Efficiency v. Carbon Monoxide at Tailpipe graph to be used in the procedure. A source of extra hydrocarbon is injected into the carburetor air intake to enrich the fuel mixture to the engine without affecting the basic carburetor settings. The engine and converter are thus overfueled thereby oxygen starving the converter to minimize any catalytic action. The carbon monoxide level is then read.

Abstract: A novel enzymatic reagent and method is provided for increasing the sensitivity of enzymatic substrate analyses using oxygen rate analyzers. The reagent is a buffered solution containing an enzyme which reacts specifically with oxygen and with the substrate being measured. The reagent also contains a salt or a combination of salts in quantities sufficient to reduce the solubility of oxygen in the reagent by at least thirty percent when compared to the solubility of oxygen in water. Upon being mixed with a specimen containing the specific enzyme substrate being measured, the enzyme catalyzes the reaction of the substrate and the oxygen. The rate of reaction of oxygen is measured, and the amount of total substrate is determined by means which translate the rate of oxygen consumption into the concentration of total substrate present in the specimen.

Abstract: A signal conditioning circuit for extracting unipolar noise from an analog input signal by isolating the unipolar noise component and subtracting it from the input signal. The circuit includes a coupling capacitor receiving the analog signal and an ideal clamp connected to the capacitor output terminal to clamp the capacitor to an edge of the unipolar noise signal. The capacitor is thus prevented from charging toward a level representing an average value of the unipolar noise and hence functions to pass the noise undistorted for subtraction from the analog input signal. The clamp comprises an operational amplifier having a first input terminal connected to the capacitor output terminal and a second input terminal connected to a source of reference voltage. A diode is connected in a feedback path between an output terminal of the amplifier and the first input terminal thereof.

Abstract: A multi-compartment centrifuge rotor having a sealing element which automatically controls in response to the centrifugation operation the fluid communication between the separate chambers within the rotor. The sealing element is situated within the rotor above an annular and an inner chamber used for containing a fluid mixture. When the rotor is assembled and stationary, the sealing element establishes a seal between the respective chambers. During the rotation of the rotor, centrifugal forces exerted directly on the sealing member cause it to move and release the seal between the respective chambers to allow fluid communication between the chambers. As the rotor returns to a stationary position and the centrifugal forces induced on the sealing member subside, the sealing element automatically re-establishes the seal between the respective chambers.

Abstract: A voltage regulator circuit including an operational amplifier having supply voltage terminals connected to a source of unregulated supply voltage and a two-terminal, essentially zero temperature coefficient, semiconductor bandgap voltage reference circuit connected in a negative feedback path between the output terminal and one input terminal of the amplifier. The amplifier provides a constant current source for the bandgap voltage reference circuit, and the amplifier and reference circuit cooperate to establish a regulated output voltage at the amplifier output terminal. A resistive divider network is connected in a positive feedback path between the output and a second input terminal of the amplifier to establish the value of the regulated voltage within a range of values between the bandgap voltage and the unregulated supply voltage.

Abstract: An automatically controlled liquid dispensing system including a reagent dispenser adapted to function as an intermediate container for dispensing relatively small controlled volumes of liquid to an associated receiving system in a continuous "demand" mode, this dispenser being indirectly monitored to be automatically and continually replenished after liquid is withdrawn therefrom, using a simple photoelectric liquid level monitor system including a fail-safe overflow control arrangement.

Abstract: An identification means placed adjacent the test tube cavities in a centrifuge rotor. The identification means utilizes recessed or indented indicia which are positioned on a circular ring raised above the generally flat top surface of the rotor. The identification indicia are used for identifying or labeling each of the test tube cavities in the rotor. The raised nature of the ring eliminates the possible establishment of weak points or areas in the top surface of the rotor during centrifugation.

Abstract: A system for chemically analyzing antigens or antibodies by initiating an antigen-antibody reaction in a reaction zone and measuring the light scattered by a precipitate produced by the reaction to determine the antigen or antibody concentration. In order to signal the start of the reaction, a fluorescent tagging substance is included with at least the last antigen or antibody reaction component introduced into the reaction zone. The fluorescent tagging substance does not enter into the antigen-antibody reaction and is selected to emit light in a bandwidth spectrally separated from the light scattered by the precipitate. The reaction zone is monitored for the presence of the tagging substance, and when the substance is detected a trigger signal is generated to signal the start of the reaction.

Abstract: An improved automotive ignition analyzer is provided for use with electronic ignition systems. A quadrature field magnetic pickup is utilized to detect signals in the secondary circuit of the ignition system. An adaptor including a voltage clamp is connected to the tachometer lead of the electronic ignition system so that a power balance test may be performed in the conventional manner without harming the electronic ignition system.

Abstract: A double beam optical null spectrophotometer having sample and reference optical beam paths, a detector common to both paths, and an attenuator feedback loop from the detector for adjusting the position of an optical attenuator in the reference beam path to balance the energy in the two paths. The slider of an attenuator transmitting potentiometer follows the position of the optical attenuator and a signal level sensitive impedance network connected to the slider calibrates the potentiometer such that an output signal therefrom indicates the true transmittance of a sample in the sample beam path over a range of transmittance values from zero to one hundred percent transmittance.

Abstract: An air driven centrifuge which utilizes a stator with a floating stator pad for alleviating excessive vibration of the rotor associated with critical rotating speeds. The floating stator pad incorporates means for increasing the friction between the pad and the stator in order to increase the ability of the stator pad to provide greater dampening of the rotor for improving the smoothness and stability of its operation.

Abstract: A reagent system for beta-amylase assay comprising:A polysaccharide having glucose molecules primarily connected through alpha 1,4 linkagesPhosphate ionsMaltose phosphorylaseA co-enzyme selected from a group consisting of beta-nicotinamide-adenine dinucleotide, beta-nicotinamide-adenine dinucleotide phosphate, and mixture thereofGlucose-6-phosphate dehydrogenaseBeta-D-phosphoglucomutaseMutarotase.

Abstract: Erythrocytes derived from certain animal or fowl blood are specially treated to produce a substance which is readily agglutinable by viruses and by certain types of antibodies. The substance possesses properties of stability, sensitivity and agglutinability which are utilized in a serological diagnostic test for viral diseases.

Abstract: A dual seal arrangement for use in a rotor to ensure the retention of the fluid sample within the test tube cavity during high speed centrifugation in an ultracentrifuge. The dual seal arrangement provides not only a seal on the test tube within the rotor tube cavity, but also a seal on the rotor tube cavity itself. One seal provides a capping arrangement on the test tube to securely seal the fluid sample within the test tube which rests within the rotor tube cavity. A secondary seal is positioned within the rotor tube cavity above the capping seal to provide a complete seal of the rotor tube cavity above the test tube.

Abstract: A valve construction in the form of a "flex-finger" or flexible stem valve is provided for handling substances which are highly corrosive or very active chemically. The valve body, valve seats, a valve ball and flexible finger or flexible valve stem are all composed of chemically resistant material. The flexible stem has an outer end secured in the valve body against rotation with a fluid tight joint and an inner end for actuating the "ball". The flexible stem is composed of material which is sufficiently resilient so that it may be caused to travel in a circular or orbital path carrying or actuating a "ball" or other attachment into and out of engagement with the valve seat or seats.

Abstract: Apparatus for the analysis of samples such as blood or urine includes a reaction cell for reacting the sample with a chemical reagent at a predetermined temperature. A heat exchanger is provided on the reaction cell for establishing the temperature of the cell. Reagent is pumped into the cell through a conduit, and a portion of the conduit is wound around the reaction cell in contact with the heat exchanger to preheat reagent in the conduit before the reagent is pumped into the cell.

Abstract: Nematic liquid crystal compositions for use in displays and in other liquid crystal applications comprising a mixture of a nematic biphenyl liquid crystal material, nematic liquid crystal material other than nematic biphenyl which is incompatible with the nematic biphenyl (e.g. when mixed together, it will form a smectic phase instead of a nematic phase) which is present in a concentration that will render the total mixture with improved electro-optic properties and nematic liquid crystal material other than a nematic biphenyl which is compatible with the nematic biphenyl and present in a concentration sufficient so that the mixture forms a satisfactory nematic phase for use in a field-effect display device. The preferred biphenyl-incompatible constituents are certain ester-type nematic liquid crystals and the biphenyl-compatible constituent are other certain ester-type nematic liquid crystal.