Abstract: An acoustic capacitor of minimum size and minimum susceptability to temperature-induced internal pressure change. The capacitor comprises an insulated container having an internal member of high heat capacity material surrounded by a porous thermally conductive material; the member acts as a heat sink, slowing the rate of change of pressure due to change in ambient temperature. The internal pressure that is built up due to temperature change is bled off by the same orifice that equilibrates the internal pressure to ambient atmospheric pressure.

Abstract: A method of inspecting the reinforcing members in prestressed concrete beams by generating a magnetic field close to the beam and measuring the field by means of a Hall effect sensor located between the pole pieces of the magnet. A partial or total break in a reinforcing member produces an anomaly in the magnetic field, which in turn registers as a voltage "spike" in the output of the Hall effect sensor. The method further includes a method for enhancing the data by substantially reducing or eliminating the effects of transverse reinforcing steel or support members located at the site of a break in the prestressed member.

Abstract: A method of inspecting the reinforcing members in prestressed concrete beams by generating a magnetic field close to the beam and measuring the field by means of a Hall effect sensor located between the pole pieces of the magnet. A partial or total break in a reinforcing member produces an anomaly in the magnetic field, which in turn registers as a voltage "spike" in the output of the Hall effect sensor. The method further includes a method for enhancing the data by substantially reducing or eliminating the effects of transverse reinforcing steel or support members located at the site of a break in the prestressed member.

Abstract: A digital Moving Target Indicator (MTI) radar system for rejection of low velocity "clutter" by utilizing techniques to identify those radar echo returns from targets having radial velocities lower than fixed predetermined values. For digital MTI radars that have a response which is a periodic function of the radar's Pulse Repetition Frequency (PRF) and doppler frequency shift of the received radar signal relationships exist whereby (a) optimum target velocities which correspond to the maximum canceler gain can be calculated from the radar's PRF; (b) the canceler response can be expressed in terms of a periodic canceler response function which incorporates the ratio of the actual target velocity to the optimum target velocity; and, (c) the output amplitude from the canceler can be determined from the input amplitude to the canceler produced by the MTI receiver's coherent phase detector and the periodic canceler response function.

Abstract: An electric blasting cap designed to be permanently disabled by the application of an external magnetic field. The cap contains a magnetic reed switch which creates an open circuit or a short circuit to prevent current from reaching the bridge wire. One embodiment of the switch is operated by a magnetizing field, the other is operated by a demagnetizing field.

Abstract: The invention encompasses a removable strain gauge fixture, and a method for measuring accumulated stress in a structural component, such as a railroad rail. The strain gauge fixture generally comprises first and second side pieces connected by a strain concentrating bar of reduced cross-section, an electronic strain sensor mounted on the bar, and first and second tapered pins extending from the front faces of each of the side pieces. The tapered pins transmit accumulated strain from the component being measured to the strain focusing bar when the pins are inserted into mating holes in the component.

Abstract: A simulated rail car identification system including a plurality of coded labels mounted at spaced apart locations on an endless conveyor. The conveyor produces horizontal movement of the labels sequentially through a zone viewed by an optical scanner. A control system monitors and controls operation of the endless conveyor and generates block signals responsive to the relative position thereof and wheel signals responsive to the entry of individual labels into the viewing zone. Processing and decoding of the information retained by the moving labels is accomplished by a data processor that receives the output of the scanner and the block and wheel signals from the control system. The effectiveness of the scanner and processor are determined by comparing their output to the data programmed into the control system and encoded on the moving labels.

Abstract: Portable apparatus for use in measuring vertical deviation of the surface of a rail from a reference plane. The measuring device includes a pair of guide beams and a hand-powered carriage which move along the beams. A sensor, which follows undulations resulting from rail wear, is mounted on the carriage and is coupled to the pen of a recorder.

Abstract: The measurement of small differential temperatures over a wide range of absolute temperatures is accomplished by cyclically switching the excitation polarity to a bridge circuit including the temperature sensors. Additionally, the measuring circuitry includes a differential-differential amplifier configuration and a pair of compensating conductors in the cable to each sensor to achieve equal resistance in each excitation path.

Abstract: A method of detoxifying organotin-containing paint residues that are sandblasted from the bottom of a ship's hull comprising cleaving the tincarbon bond by application of an oxidizing agent, preferably nitric acid.

Abstract: The separation between aircraft approaching a common runway is minimized by measuring the existing wind conditions at a preselected point relative to the runway threshold and basing a prediction of the movement of wake vortices on the measured conditions. The prediction of vortex movement is based upon a vortex advisory algorithm prepared from a plot of wind conditions which predictably remove vortices from the flight path.

Abstract: Disclosed is an omnidirectional antenna comprising vertically stacked pairs of folded slot antennas. Each slot antenna is electrically loaded to allow reduction of slot physical dimensions to the point that the diameter of two slots when mounted back-to-back is less than one wavelength. The resulting antenna produces a highly omnidirectional signal having vertical polarization. Vertical beam shaping is achieved by selection of the phase and magnitude of the signal transmitted by each pair of folded slot elements.

Abstract: Disclosed is improved distance measuring equipment comprising an airborne FM coded, chirp, interrogator transmitter in combination with a weighted matched receiver in a ground transponder. The airborne transmitter produces a long low power frequency modulated output pulse. Detection in the transponder receiver is accomplished by pulse compression matched filter techniques.