Abstract: A series of pulses are transmitted to a first laser and the same series of ulses through a time delay network to a second laser. Each laser provides pulses of light through separate diagonal mirrors and through respective transparent holograms. Each light beam is then brought into convergence by respective sides of a wedge shaped reflector and brought into spacially coincident focus by an imaging lens onto the surface of a sample under test. The two hologram transparencies are imaged spacially coincident but separated in time on the face of the sample. Thermal elastic waves produced by laser heating at the sample surface transform into a desired acoustic beam pattern determined by the nature of the wavefronts which the hologram transparency represents. The position of the coincident image on the sample may be moved by varying the time between the two pulses.

Abstract: A transducer is provided having interconnections between a conductive member and one side of a heat sensitive piezoelectric substrate such as PVF.sub.2 to or from which electric signals flow. The interconnections are positioned on one side of the substrate with the opposite side having a metalization under the interconnection attachment positions and in a continuous region therebetween. The interconnection includes adhesive material such as epoxy disposed between and attaching an electrically conductive member to one side of the substrate and a single contiguous electrically conductive coating applied to adjacent portions of these two members to electrically connect them. Since both interconnections are positioned on one side of the substrate the transducer is adhesively fastenable to operational structure with a strong bond line, permits lead attachment after mounting and prevents lead shortout.

Abstract: A mechanical and electrical connection for a piezoelectric member of polyic material such as polyvinylidene fluoride, and method for forming such a connection. To form the connection, the piezoelectric member is first masked to prevent a preselected portion of its surface from being coated during subsequent coating operations. An electrically conductive member such as a lead wire or a solderable terminal is then attached to the nonmasked area of the piezoelectric member with adhesive such as epoxy. The masked piezoelectric member, the electrically conductive member, and (incidentally) the mask are then coated with a conductive coating such as sputtered gold to electrically connect the conductive member to the piezoelectric member. The mask can now be removed from the piezoelectric member if desired, although it can be left in place as a convenient vise.

Abstract: The present invention provides for the accurate mapping of shallow crustal earth formations by means for refractive seismic waves to identify structure, elastic parameters and lithology of the strata undergoing survey to indicate deposits of ore, marker rock, economic minerals and the like. After a "roll-along" technique has been used in the field to collect the refraction data and preliminary processing steps undertaken in which there are provisions for (i) accurate separation and determination of seismic shear and compressional responses; (ii) stacking displays that allow for accurate identification of shape of the surveyed strata; and (iii) final depth displays of the refracting bed segments associated with seismic shear and compressional wave velocities as well as Poisson's ratios, in accordance with the present invention, additional processing then occurs.

Abstract: A mechanical and electrical connection for a piezoelectric member of polyic material such as polyvinylidene fluoride, and method for forming such a connection. To form the connection, the piezoelectric member is first masked to prevent a preselected portion of its surface from being coated during subsequent coating operations. An electrically conductive member such as a lead wire or a solderable terminal is then attached to the nonmasked area of the piezoelectric member with adhesive such as epoxy. The masked piezoelectric member, the electrically conductive member, and (incidentally) the mask are then coated with a conductive coating such as sputtered gold to electrically connect the conductive member to the piezoelectric member. The mask can now be removed from the piezoelectric member if desired, although it can be left in place as a convenient vise.

Abstract: A cone drive, high output speed reducer, having a low clearance for low profile applications. An input shaft drives a helical idler pinion which in turn drives two other helical idler pinions. The two other idler pinions are each mounted on a separate shaft carrying a cone drive worm. The two worm shafts turn in unison, and the worms are each meshed with a separate worm gear. The two worm gears are operatively mounted on an output shaft. One of the helical idler pinions is provided with an adjustment means for equalizing the load sharing. That is, to provide equal loads on each of the helical pinions for load sharing throughout the twin drive gearing units of the speed reducer. The speed reducer may be provided with either an air cooling system or a water cooling system.

Abstract: Apparatus and method for producing maps of thickness or elastic constant iations of nominally plane sheet or plate materials. Amplitude variation at a set frequency on a normal resonance peak is recorded to determine resonance peak variation and thus specimen thickness or elastic constant variation. A mechanical scanner moves a transducer across the material submerged in a water tank for performing an ultrasonic C-scan. A transmitter or pulse generator repeatedly pulses the transducer to produce a focused narrow pulse of ultrasound which reverberates within the material. Echoes from the material in response to the pulse are received by the same or another synchronously moving transducer, whose resulting signal then passes through a gate, which removes extraneous signals and selects the number of multiple echoes and thus amplitude range desired, and a variable filter controlled by a function generator which selects the desired frequency, to a pen recorder.

Abstract: Sheet feeding device and method for feeding sheets of two different regular lengths, comprising a sheet length detector for automatically sensing the length of the next sheet in the sheet-supply station of the device, prior to movement of said sheet and conveying this information to the logic system which controls the operation of the machine. The detector is attached to the machine for automatic movement into the sheet-supply station, which is normal operating position, and for automatic withdrawal out of the sheet-supply station to provide easy access to the sheet-supply station for the insertion of new sheet stacks and to prevent damage to the sensitive detector during the insertion of such sheet stacks.

Abstract: A device for acquiring and displaying acoustic emission fatigue data so as to facilitate the interpretation of dynamic micromechanical failure processes in materials. The load on a specimen under cyclic loading is monitored by a load cell whose output is sent to a cycle counter. The specimen is also monitored by a transducer which senses acoustic emissions. The signal produced by the transducer passes through a preamplifier, filter, amplifier and threshold detector to a pulse generator whose output is connected to the intensity modulation input of an oscilloscope or other cartesian coordinate arraying device. The load cell output is also connected to the vertical deflection input of the oscilloscope. The counter output is connected to the horizontal deflection input of the oscilloscope.

Abstract: A method and apparatus for determining fatigue in a structural part. The fatigue sensor comprises, for example, a thin silver zinc film affixed to a structural member that is to be monitored for fatigue damage. Upon sufficient flexing or other cold working, the silver zinc film undergoes a color change, pink to silver, to thereby indicate that the structural member has reached predetermined fatigue levels.