Abstract: First and second tractor assemblies apply a preset tension to incremental lengths of fiber which moves continuously through the apparatus. The apparatus performs the functions of fiber pulling and non-destructive testing of all of the fiber. Each tractor assembly includes a tractor wheel and belt wheels. A belt extends around the belt wheels and engages the tractor wheel in an arc. The fiber passes between the belt and the tractor wheel in this arc. The second tractor assembly has a constant torque drive with an unloaded speed which is faster than that of the first tractor assembly. The second tractor assembly pulls the fiber thereby reducing the speed by causing the constant torque device to overload and slip.

Abstract: A furnace for melting thermoplastic material, such as glass, includes a vertical furnace with electrodes at different levels immersed to different depths in the molten material. The convection currents and size, shape and stability of the fusion zone are controlled by changing the amount of power and the depth of immersion of the electrodes at different levels. For example, the electrodes in one of the lower tiers extend closer to the center of the furnace to produce a central upward convection current, to prevent an unstable fusion zone due to temperature gradients from wall to center, and to decrease the temperature near the furnace wall. For glasses with steep temperature-resistivity relationships and/or high infra-red absorption characteristics, the advantages of using differently immersed electrodes are even more significant.

Abstract: A system for delivering separator material to a drum upon which optical waveguides are wound. The sheet material is delivered to the vicinity of the drum through a partially-enclosed guide and cut to length. Air jets are provided for urging the severed sheet material against the drum so that a succeeding layer of waveguides can be wound upon it.

Abstract: A recorder pen is mounted on the sample scanning stage of an electrophoretic sample analyzer. Movement of the stage scans the sample optically while, at the same time, the recorder pen produces an analog record of the optical analysis. A sample holder is mounted in the stage for detented movement in the direction orthogonal to the scanning motion of the sample stage. The sample holder can be moved to one of several detented positions so that different tracks of the samples are scanned.

Abstract: An analyzer for electrophoretic samples includes a sensor of extremities, more particularly valleys, in the output from the detector. The analysis of electrophoretic samples includes integration of the area under each of the fractions of the multicomponent output. In order to integrate each of the components, it is necessary to detect valleys in the output. The detector output is first applied to a non-linear processor such as a logarithmic amplifier and a differentiator. The logarithmic amplifier changes the shape of the output to make the detection less dependent upon relative component amplitude. A threshold comparator produces a pulse when the slope of the analyzer output, as represented by the output of the differentiator, exceeds a threshold. The threshold is changed after the detection of the first valley. Noise suppression circuitry prevents the detector from responding to closely occurring extremities in the analyzer output.

Abstract: An automatic recording fluorometer/densitometer has an integral viewer for viewing and photographing fluorescent samples which have been applied to a clear, thin-film substrate. Light from an ultraviolet source is on the opposite side of the sample from the viewer when the sample is placed in a viewer holder. When the sample is placed in a recording holder, light from the same source is on the opposite side of the sample from the recorder optics. By having the source on the opposite side from the optics, it is possible to have the source much closer to the sample and to thereby reduce the stray ultraviolet light in the instrument. Another source emits visible light for densitometric analysis of the sample. A movable filter holder can be indexed to different positions for placing an ultraviolet filter or one of the densitometric filters in the optical path between the sources and the recording device.

Abstract: An analyzer for electrophoretic samples has a sample stage movable linearly with respect to a source and a detector of analysis energy. During a first scan of the sample, a voltage is produced representing either the minimum detected fluorescence or the minimum detected optical density. During a second scan, the voltage is combined with the output of the detector to automatically correct the output to a reference.

Abstract: A test sample for testing a recording fluorometer/densitometer has multiple tracks with features that generate detector outputs indicating performance parameters. In the normal mode of operation the instrument scans the optical absorbance or fluorescence characteristics of electrophoretic samples in a plurality of tracks on a thin agarose film plate. In order to correctly record the optical characteristics of these electrophoretic samples, the instrument must respond linearly and with the correct range, resolution and alignment. A test sample is scanned in the same manner as a normal sample. The resulting instrument output provides easily analyzed information on fluorometric and densitometric performance parameters including linearity, range, spatial resolution, slit and scan path alignments, scan speed and excitation uniformities, response time, noise, electrical and optical offsets, integration accuracies, automatic gain and zeroing accuracies.

Abstract: An automatic calibration system for pH meters includes a digital counter and a digital-to-analog converter which produces an output voltage connected to compensate the zero offset DC voltage of the pH measurement system. During a calibration operation a switch is closed to reset the binary counters and to thereafter supply clock pulses to the counters. As these clock pulses are counted, the digital-to-analog converter produces a staircase output voltage. This is applied to one input of a difference amplifier and the measuring voltage of the pH probe is applied to the other input. A detector stops the application of clock pulses to the counter when the staircase voltage equals the DC offset voltage of the pH measuring probe.