Abstract: The battery of the invention includes at least one electrochemical cell for use and recharging underwater, particularly seawater, at a pressure at or greater than atmospheric pressure. The battery has an anode, a cathode, an associated electrolyte in a housing, and a pressure compensation fluid which has a density greater than water, but preferably between the density of water and the density of the electrolyte. Preferably the pressure compensation fluid has a density of about 1.2 g/cm.sup.3, and is non-conductive. Apparatus to compensate for changes in volume are provided, as are components for the escape of internally generated gases.

Abstract: A method of screening communication functions in a human subject comprises (a) presenting a verbal auditory stimulus to the subject, and then (b) scoring a response to the verbal auditory stimulus, with the response being an expressive response, a receptive response, or both. These steps are then cyclically repeated to provide an evaluation of the subject's response to a plurality of verbal auditory stimuli. Once the evaluation is complete, the evaluation is used to determine whether the subject should receive further diagnostic testing. In a preferred embodiment of the invention, subjects are deliberately confounded during the receptive portion of the test.

Abstract: An electromagnetic shearflowmeter for remote oceanic applications is disclosed, wherein a pair of housings, each having disposed therein an electric coil, are spaced to define an open cylinder through which a fluid in which the shearflowmeter is immersed may flow relatively free of obstructions. Electrodes are embedded symmetrically in the surfaces of the housings for sensing electromagnetic signals deriving from activation of the coils and which signals are modified as a function of the rate and direction of flow through the open cylinder of the fluid in which the apparatus is immersed. A plurality of such apparatus may be operated at different depths along a common mooring to measure differentials of flow, also called shear, within the fluid system. An electronic amplification circuit having an excellent common mode-rejection ratio and common mode range, used in conjunction with the other apparatus, is also disclosed.

Abstract: A portable precision automatic audiometer for testing hearing of an individual utilizes a voltage programmable oscillator in combination with a preprogrammed logic circuit to generate and transmit sweep frequency tones automatically or fixed frequency tones under manual control into a suitable earphone worn by the individual examinee being tested. A voltage proportional attenuator is controlled by an examinee manually operated switch and enables the examinee being tested to regulate the level of sound pressure to which he is being exposed, while a chart recording instrument simultaneously graphs the audiogram of his test responses. Improvements are provided with respect to noise reduction and ease of calibration.