In a method and apparatus for testing and determining the tack properties of rubbery or polymeric compositions test specimens of polymer stock are each supported on a perforated plate or grid so that the specimen completely covers the perforated area. A differential air pressure is applied across the specimen plate contact area thereby forcing the specimen against the plate and maintaining the former in position. Two test specimens of polymer stock, each thus mounted, are then pressed together u...

Measuring and calculating apparatus with which engineering functions necessary to the designing layout and construction of structures such as roads, canals, etc., can be performed easily and accurately directly from a contour map of the area in which the structure is to be constructed, thereby eliminating the need for extensive on-site observations or time consuming template utilization.

Blood serum is tested for the presence of urea nitrogen by reacting urea present in the serum with an aqueous reagent having a pH of between 0.4 and 1.5 and containing diacetylmonoxime, phenazone, arsenic pentoxide and sulfuric acid. Reaction is effected by heating the serum-reagent mixture to 85.degree. to 100.degree. C., cooling and measuring the optical absorbance of the cooled mixture at a wavelength between 450 and 485 nm.

Device for determining the transparency of the atmosphere between two points comprising one light transmitter and one receiver respectively on the two points, optic fibers connecting the corresponding transmitters and receivers, means to separate the data coming through the atmosphere and through the fibers and a data processing device connected to said means.

A network which determines whether the slope of a pattern, representing an input signal, is positive going or negative going in selected portions of the pattern. The existence of positive or negative slopes is determined by sampling amplitude components from a sequence of channels representing the pattern and then comparing a plurality of adjacent components with a successive plurality of adjacent components to decide whether the amplitude of the pattern is increasing or decreasing in selected p...

A frequency determining resistance leg of an oscillator is constructed as a ladder network, each of the resistors having a value relationship to each other defined by a specific set of simultaneous equations related to frequency parameters of the oscillator. The resulting resistor values comprise a ladder network which, when connected to an oscillator through a push button pad, causes oscillation of the oscillator at predetermined frequencies having specific band widths; but when two adjacent pu...

Horizontal deflection in a sampling oscilloscope is accurately determined by measuring the time difference between the occurrence of a triggering signal and the occurrence of a strobe or sample-producing signal. For measuring this time difference, a net charge of a first is accumulated in response to a first sequence polarity these signals, the value of the charge accurately indicating such time difference. If the signal sequence is reversed, a charge of a second polarity is accumulated with the...

A calibrated precision tube with an inlet and an outlet, and having a pressure transmitter at the bottom, is used for determining the mass of liquids.

The inner wall of a cylindrical glass envelope is delineated by a combination of a diffused light source and peripheral shutters placed behind the envelope. The precise position of the shutters is adjusted to block some of the peripheral light from the source from reaching the envelope. When the article is viewed from the front, dark lines delineate the lateral extent of the inner wall of the envelope. With the help of such a delineation it is possible to check the accuracy of the assembly of co...

Improvements in the sensitivity and reproducibility of nephelometric endotoxin determinations using endotoxin-activated enzyme from Limulus amebocyte lysate are achieved by contacting endotoxin-coagulated lysate with an ionic surface active suspending agent, generally a mixture of detergent and suspending agent. Instrumentation improvements further enhance results.