Abstract: A set point adjust mechanism is disclosed for use with process controllers to manually adjust the set point value and simultaneously change the set point value indicated. The set point adjust mechanism includes a manually actuable thumbwheel and an idler wheel mounted in contact with each other on a slider. Thumb pressure on the thumbwheel causes the slider to move so that the idler wheel contacts an indicator drive wheel. The set point value source, usually a potentiometer, is connected to the indicator drive wheel which also drives a belt that positions a pointer with respect to a scale. The pointer and scale provide the set point indication. When the pointer hits a pointer stop, or for any other reason resists motion, further rotation of the thumbwheel causes the idler wheel to move to engage a mechanical stop to prevent further thumb pressure from causing dislocation between the indicated set point value and the set point value source.

Abstract: The derivatives of digoxin useful in the radioimmunoassay of digoxin having the following formulae: ##STR1## where R is a carboxylic acid ester. These derivatives are formed by the following process: (1) reacting the carboxylic acid in the presence of trifluoroacetic anhydride with a solution of digoxin in an inert, nonaqueous solvent medium, (2) adding water so as to form the above derivatives, (3) purifying the above derivatives from other constituents of the reaction mixture and (4) radio-labeling these derivatives for use as a labeled hapten in the radioimmunoassay of digoxin.The preferred carboxylic acids are imidazoleacetic acid and p-hydroxyphenylpropionic acid. The preferred radioactive isotope is .sup.125 I.

Abstract: Nematic liquid crystal materials suitable for use in displays and in other liquid crystal applications comprising particular combinations of positive and negative dielectric anisotropy nematic materials are disclosed.

Abstract: Improved apparatus for bringing a fluid in a process stream in contact with a sensor is disclosed. The present invention uses the kinetic energy of the process fluid to convey some of the fluid to and from the sensor, as opposed to the prior art practice of inserting the sensor itself into the process fluid stream. A nozzle is placed into the process fluid stream facing into the direction of flow. A small portion of the flowing process fluid is trapped by the nozzle and some of its kinetic energy is converted to pressure. This pressure causes a flow from the nozzle into a conduit through an open valve to the sensor. The fluid continues past the sensor and returns to the process fluid stream through the same valve. In one embodiment, the path for incoming fluid and exiting fluid are separate paths. In a second embodiment, the incoming fluid and exiting fluid exist coaxially.

Abstract: A method for determining the source strength of a radioactive sample such as iodine-125 or cobalt-60, which emit pairs of quanta of radiation in coincidence, or near coincidence, and for determining the counting efficiency of a detection instrument analyzing such samples. A first counting channel is used to count events attributable to single quanta, a second counting channel is used to count events attributable to coincident pairs of quanta, and the sample source strength is computed from the results of measurement in these two counting channels. Then, the counting efficiency in a third channel designed for subsequent use in analyzing test samples may be determined from the counting of events in the third channel.

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: 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: 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: 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: 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: 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: 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: 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: An electrochemical reference electrode for use in ion potential measurements of solutions. The liquid junction structure of the electrode comprises a hydrophobic polymer having a suitable salt distributed therethrough and held in place to prevent leaching by a filamentary structure of the polymer. The liquid junction structure is a diffusion membrane material and permits ionic communication between the salt bridge solution of the electrode and the sample solution essentially by means of diffusion, rather than by liquid flow. The entire electrode body may be made of the polymeric material. The electrode is particularly suited for process applications.

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 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: 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.