Abstract: An electrochemical combination electrode assembly particularly adapted for measuring the pH of body portions of a living subject, such as skin, hair, and the like, and which can be operated in any vertical, inclined or horizontal orientation. The assembly comprises a pH-indicating glass electrode supported within a tubular plastic container and includes a generally flat, pH-sensitive structure at a sensing end of the assembly. Conventional indicating and reference half-cell electrodes are supported in separate reservoirs of the assembly containing internal and reference electrolytes, respectively. The upper ends of the reservoirs are sealed by elastomeric plugs which compensate for differing coefficients of expansion within the assembly and coact with the electrolytes to prevent formation and migration of air bubbles to the sensing end of the assembly.

Abstract: A vacuum seal for use in a continuous flow centrifuge apparatus for minimizing heat transfer from the vacuum bushing to the rotary transfer tube which is conducting the sample solution to the centrifuge rotor. An elongate, cylindrical sleeve surrounds the transfer tube, coaxial therewith and spaced therefrom, adjacent the upper end thereof, between the transfer tube and the vacuum bushing, the bushing creating an oil film around the transfer tube to provide the vacuum seal, the annulus formed between the inner surface of the sleeve and the outer surface of the transfer tube isolating the transfer tube from the heat created in the oil film.

Abstract: In a centrifuge rotor of the type including a yoke and an enclosure for the yoke, the enclosure being operatively connected to the yoke for rotation therewith, the enclosure comprising a wind shield physically connected to the bottom of the yoke and extending beneath the yoke and around the sides thereof and a lid being positionable over the yoke to engage the wind shield for completely enclosing the yoke, there is disclosed a method and means for retaining the lid in contact with the wind shield wherein the wind shield terminates in an upwardly facing circular lip and the cover terminates in a downwardly facing circular lip so that the lip of the lid engages the lip of the wind shield, there being no physical connection between the lid and the wind shield, the lid being retained in contact with the shield during rotation of the centrifuge rotor by the force created by the naturally-occurring low pressure within the enclosure, beneath the lid.

Abstract: Method and apparatus for generating a sweep signal for the oscilloscope of an engine ignition analyzer, employing a lock loop with phase detector, integrator and voltage controlled oscillator. The oscillator provides a ramp voltage for use as a sweep signal. A feedback circuit provides a feedback signal to the input of the phase detector when the ramp voltage reaches a predetermined value for phase comparison with a reference signal related in time to an engine ignition event. The intetrator output controls the slope of the ramp voltage. When the two input signals to the phase detector are out of phase, the slope of the ramp voltage is changed via the integrator to reduce the phase difference. The ramp voltage provides a sweep signal of substantially constant length while the engine speed varies over the range of idling to full speed.

Abstract: In a swinging bucket centrifuge rotor of the type including a core with outwardly extending support arms having removable trunnion pins for supporting a plurality of bucket assemblies, each bucket assembly including a rotor bucket support having a pocket on opposite sides thereof for receiving the extremities of adjacent pins, there is disclosed an improvement wherein each of the arms has only a single hole formed in the outer end thereof, perpendicular to the longitudinal axis thereof, for receipt of a single trunnion pin including a central portion and acutely oriented opposite extremities, the opposite extremities of each trunnion pin extending outwardly from the arms towards and coaxial with the outwardly extending extremities of the pins of adjacent arms, and wherein the pockets in each support are cut into the sides thereof at an acute angle relative to the axis thereof.

Abstract: An automobile engine ignition analyzer with engine performance displayed on an oscilloscope. Circuitry for providing timing indicia on the oscilloscope trace in the form of high intensity spots or gaps, with the time intervals between indicia maintained constant as engine speed varies. A pickup for coupling the engine ignition pulse to a pulse shaping circuit which provides an output pulse related in time to the ignition pulse, and an oscillator started by the output pulse and providing a train of pulses at predetermined intervals, typically one millisecond, with the pulse train connected to the oscilloscope beam intensity control for blanking or intensifying the beam as desired.

Abstract: A timing control circuit for a strobe lamp for use in adjusting the timing of an internal combustion engine. A circuit which provides for retarding lamp triggering for setting ignition advance and for advancing lamp triggering for setting ignition retard. A circuit providing for advance and retard selection, the amount of advance or retard, and zero degree triggering for engines with various numbers of cylinders. A circuit with a ramp voltage synchronized with engine timing, a reference voltage for setting the amount of advance or retard, and a comparator which provides a triggering signal for the lamp when the ramp and reference voltages match.

Abstract: Titration apparatus for measuring chloride electrolyte in blood samples including a pair of coulometric generator electrodes for titrating the chloride with silver ions to precipitate silver chloride and a pair of amperometric detector electrodes for detecting completion of the silver chloride precipitation. The amperometric electrodes and one of the coulometric electrodes (cathode) are contained in a unitary electrode module which is mounted separately from the remaining coulometric electrode (anode) and which is readily removable for cleaning.

Abstract: Apparatus for measuring carbon dioxide and chloride in blood. A blood sample is reacted with acid in a sample container to release carbon dioxide, a portion of which diffuses through a gas-permeable membrane and reacts with an electrolyte to change the pH thereof. A pair of pH measuring electrodes monitor the electrolyte pH at respective locations adjacent to and remote from the region of reaction within the electrolyte. The pH electrodes are coupled to respective input terminals of a differential amplifier to derive a differential pH signal. The differential pH signal is differentiated to derive a rate of change of pH output signal which is measured to indicate the concentration of carbon dioxide. The pH measuring electrodes are in electrolytic communication and means is provided to renew the electrolyte between measurements. Coulometric measurement of chloride in the sample is performed simultaneously with the carbon dioxide measurement.

Abstract: A tracking accuracy control system for a spectrophotometer utilizing stepper motors for controlling the wavelength drive and chart drive system. An exact ratio between the wavelength drive motor and chart drive motor is maintained under variable speed conditions by utilizing an error signal which normally operates the reference beam attenuator, this error signal being transmitted through an absolute value circuit to produce a voltage whose magnitude is the absolute value of the error signal. This absolute value is then transmitted through a fast attack, slow release hold-over circuit to control a voltage controlled oscillator in such a way as to reduce wavelength scan speed in an amount proportional to the error while simultaneously controlling chart speed in an exact ratio to the scan speed. The output of the voltage controlled oscillator is a pulse train having a frequency proportional to the magnitude of the absolute value of error signal.

Abstract: Method and apparatus for picking up liquid sample material, such as blood serum, in a sample pick-up probe and for ejecting the sample from the probe into a reagent chemically reactive with the sample for analysis. Before ejecting the sample from the probe, the probe is inserted into the reagent for a period of time sufficient for the reagent to consume any residue of sample adherent to the exterior of the probe. Thereafter, the sample to be analyzed is ejected from the probe into the reagent and the resulting sample-reagent reaction is measured. Isolation between the sample within the probe and the reagent may be maintained while the probe is in the reagent by a bubble of air drawn into a tip end of the probe before inserting the probe into the reagent.

Abstract: A liquid scintillation solution which includes (1) a scintillation solvent, (2) a primary scintillation solute, (3) a secondary scintillation solute, (4) a plurality of substantially different surfactants and (5) a filter dissolving and/or transparentizing agent.

Abstract: Method and apparatus for picking up liquid sample material, such as blood serum, in a sample pick-up probe and for ejecting the sample from the probe into a reagent chemically reactive with the sample for analysis. Before ejecting the sample from the probe, the probe is inserted into the reagent for a period of time sufficient for the reagent to consume any residue of sample adherent to the exterior of the probe. Thereafter, the sample to be analyzed is ejected from the probe into the reagent and the resulting sample-reagent reaction is measured. Isolation between the sample within the probe and the reagent may be maintained while the probe is in the reagent by a bubble of air drawn into a tip end of the probe before inserting the probe into the reagent.

Abstract: A rotor for a centrifuge including a symmetrically shaped rotor body adapted for rotation about its axis and including a suitable cavity for receipt of samples to be centrifuged. The rotor body is provided with means adapted to cooperate with a centrifuge driving means for rotating the rotor body abouts its axis for centrifuging liquid samples in the cavity. The rotor body is provided with an annular shoulder formed around the top of the rotor and surrounding the opening to the sample cavity, the shoulder having an inward facing surface adapted to receive a thin flexible disc having a bowed shape in the direction of the opening to the cavity so that the edge of the disc seats against the annular shoulder. In its preferred form the disc has a diameter greater than that of the annular space bounded by said shoulder and is bowed by a force against the center portion of the disc causing it to flex in the downward direction thereby assuming a "dish-shape" covering the opening to the cavity of the rotor body.

Abstract: An apparatus for automatically performing blood chemistry analyses and in particular the determination of the pH, PCO.sub.2 and PO.sub.2 of blood. The apparatus employs a flow cell having pH, PCO.sub.2 and PO.sub.2 measuring electrodes mounted therein adjacent to a sample passage extending through the cell. Sample is collected in a conventional syringe. The needle of the syringe is removed and the syringe cylinder is attached to the flow cell adjacent to the inlet end of the sample passage. Means are provided for automatically driving the plunger of the syringe into the cylinder to convey the sample through the sample passage. A wash solution is then conveyed through the passage to discharge the sample therefrom and thereafter a calibration solution is conveyed through the passage which permits simultaneous calibration of the pH, PCO.sub.2 and PO.sub.2 electrodes.

Abstract: A spectrophotometer including a wavelength stepper motor driving a wavelength scanning mechanism and a chart stepper motor driving a chart recorder, both motors being operative in response to driving pulses received from a system clock. The upper limit of a wavelength scan interval is established by manually adjusting the wavelength scanning mechanism to the desired limit. The length of a desired scan interval is selected by the operator and loaded into a counter which decrements in response to the driving pulse input to the wavelength motor. The counter generates an output signal after a predetermined count which clocks a switching circuit for reversing, inhibiting, or otherwise controlling the wavelength and chart motors. Other inputs to the switching circuit provide for either serial or overlay chart recording and for either continuous or manually controlled scanning.

Abstract: A liquid crystal display cell comprising a pair of oppositely disposed glass plates having transparent conductive electrodes formed on the facing surfaces thereof, said glass plates being joined by a seal material along the outer periphery thereof, with the seal material having a small opening formed therein for filling the interior volume of the cell with a liquid crystal material. A barrier is provided internally of the cell having one end joined to the seal material adjacent one side of the fill opening and having its other end extending beyond the fill opening parallel to at least one side of the display cell. The barrier extends between the glass plates, being sealed thereto, and opens into the internal volume of the cell to provide a channel communicating between the fill opening and said internal volume.

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 composition and method of forming a seal in a liquid crystal display cell wherein planar glass plates are bonded together with a dispersion of fluorocarbon and an organosilane coupling agent to form a hermetically sealed cell wherein the seal does not react with the liquid crystal material.

Abstract: An automotive ignition analyzer is disclosed with cylinder of interest of display capabilities which allows one or more cylinders to be individually selected and displayed in a stacked mode while the remaining unselected cylinders are simultaneously displayed on the same oscilloscope in a parade mode. The cylinder select mechanism may also be used for power balance purposes to prevent the ignition of the cylinder selected.