A device for determining the degree of skin sensitivity on the basis of the persistance of a streak. At least one element is provided which is to be compressed against the action of an elastic system or a spring. The outer end of this pressure element is provided with a surface which is contacted with the skin to enable a standardized pressure to be applied thereto.

A system for precisely determining the position of a beam of incident radiation. In one embodiment in the disclosure the system is utilized in an orbiting, Ritchey-Chretien telescope to determine the precise position of the image of a guide star in the focal plane of the telescope. In that embodiment a first reticle plate, having concentric ring reticle lines, is located at the edge of the tangential focal surface of the telescope and outside of the focal area being used for observation. A secon...

Apparatus for determining the density of a liquid comprises a resilient tube coupled at each end through resilient couplings to support flanges for connection in a pipeline or the like. Two cantilevers of the same material and cross section as the tube are secured to the tube so that they have a common axis parallel to that of the tube and their free ends are directed towards each other. The tube and cantilever are so excited that they vibrate in antiphase at the same transverse frequency of vib...

Apparatus, for determining the glottal waveform of a subject, is disclosed which comprises a hard-walled, uniform, cylindrical, acoustic waveguide having a cross-sectional area commensurate with that of the vocal tract of the subject. The waveguide is terminated at one end to substantially reduce acoustic wave reflections. A microphone is positioned within the wall of the waveguide to detect and convey to suitable instrumentation the glottal waveform of the subject.

An apparatus for determining the focus of a lens. The apparatus includes a light beam generating means and means for providing an output signal which indicates the focus of the lens and/or its relation to the position of optimum focus for a lens for an optical system. The means for providing the output signal can be a cylindrical chopper or an oscillating grid. Preferably the light beam generating means and the chopper are positioned in the same physical structure.

In an in vitro test for the determination of thyroxine using the competitive protein-binding technique, the improvement that comprises extracting the thyroxine into a lower alkanol or dioxane, but not separating the lower alkanol or dioxane solution of thyroxine from the serum prior to measurement of the thyroxine.

Method of rapidly determining the redox potential of a system wherein redox potential measurements are made two or more times within the first few minutes of immersion of the measuring electrodes into the system, the values plotted versus a time factor and an extrapolation made to infinite time.

In determination of the characteristics of fluid flow in a conduit, such as blood flow in a blood vessel, the signal information received from a Doppler flow-meter, in the form of a multiplicity of different frequencies simultaneously present, is filtered to give the different frequency signals on separate parallel channels and then the channels are cyclically sampled in sequence. The signal samples so obtained appear in ordered series on a common signal line and may be used to generate a C.R.T....

An arrangement for measuring frequency includes a counter unit and two multipliers connected in series with each other to the counter unit. A sensing unit senses each pulse in an unknown pulse train, the frequency of which is to be determined. The multipliers form a second pulse train, the frequency of which is proportional to the square of the content of the counter unit. The counter unit reduces its content by a predetermined amount for each pulse in the second pulse train. The sensing unit de...

Inductive position determining device which comprises a signal winding having meander curves which extend at right angles to the direction in which displacement is determined and two pick-up windings which have corresponding meander curves. The meander curves have a given width and the meander curves of the two pick-up windings show intervals of increased width in which at least one of the meander curves of the other pick-up winding is accommodated. By special proportioning of the limbs of the m...