Abstract: A sensor for measuring the speed of sound in a gas. The sensor has a helical coil, through which the gas flows before entering an inner chamber. Flow through the coil brings the gas into thermal equilibrium with the test chamber body. After the gas enters the chamber, a transducer produces an ultrasonic pulse, which is reflected from each of two faces of a target. The time difference between the two reflected signals is used to determine the speed of sound in the gas.

Abstract: A fretting fixture accessory for a_test machine (10) that induces high-cycle fatigue (at kilohertz vibration rates) in a specimen of a material under test. The fretting fixture (20) is clamped to the test specimen (21), for the purpose of testing for fretting damage. The fixture (20) is designed to provide both the normal and shearing forces that result in fretting damage.

Abstract: A dynamic force transducer for generating vertically oriented compressional forces and motions at the surface of a solid medium. A frame is rigidly coupled in direct contact with the solid medium surface. At least one pair of identical driver units are mounted to the frame to impart vertically oriented forces to the medium. Compliant springs support the drivers and introduce mechanical resonances. The driver units are excited to produce the vertically oriented pushing and pulling forces along a common collinear vertical direction. The driver units also impart either continuous or pulsed oscillatory forces to produce prescribed seismic compressional waves in the medium.

Abstract: A dynamic force transducer for generating horizontally oriented shear forces and motion at a surface of a solid medium. A rigid frame is placed in direct contact with the surface of the solid medium. At least one pair of identical dynamic-force driver units is mounted on the frame to impart horizontally oriented forces to the frame. Symmetrical pairs of compliant springs support the force drivers, but the compliances of each pair of springs may be adjusted or interchanged with other similar springs to introduce different predetermined mechanical resonances. The driver units are excited to produce the horizontally oriented forces with one or more driver units imparting a pushing force and one or more driver units simultaneously imparting a pulling force.

Abstract: A test machine (10, 40, 60) for inducing high-cycle fatigue (at kilohertz vibration rates) in a specimen of a material under test. Each test machine (10, 40, 60) provides both dynamic and static loading. One embodiment is an SEM-compatible machine (10), having an inner frame (11) containing symmetrical components on either side of a stationary node. The specimen is placed at this stationary vibration node. Dynamic loading is the result of vibrations provided by two piezoelectric actuators (16) inside the frame (11), one on each side of the node. Static loading is provided by means of two stress rods (12), each extending from an end plate (11a) into the frame (11). A pair of cylindrical couplers (14) is also inside the frame, one coupler (14) on each side of the node. Each coupler (14) is attached to an associated piezoelectric actuator (16) and stress rod (12) such that the static and dynamic loads are transferred to the couplers (14).

Abstract: An oven module for use in industrial baking applications is disclosed having apparatus for accommodating the longitudinal thermal expansion in the interior walls of the oven module located intermediate the ends of the module. The oven module is easily assembled into an oven baking line because its ends are fixed and do not vary due to thermal expansion. Therefore, the present oven module alleviates numerous disadvantages in the shipping and assembly of an oven baking line which has been experienced with prior known oven modules. The floor, walls and roof of the oven module have both an interior and an exterior structure so that the interior surfaces of the oven module can be independently and rigidly supported. At opposite ends of the module, the interior and exterior structures for the floor, walls and roof are fixed to a common support member.

Abstract: A remotely actuated clamping apparatus for obtaining a secure coupling between a vibration unit generating longitudinally directed driving forces and a probe designed for penetrating the earth, such as into underwater sediments at water depths too great for direct human intervention.

Abstract: The present apparatus and method utilizes a downhole electrolysis process implemented by means of an elongated gas generating apparatus containing an array of cascaded electrolysis cells distributed along all or part of the borehole length to be fractured. In one use of the present invention in a deep or a shallow drilled borehole, an electrical current delivered downhole converts an appropriate electrolyte to a stoichiometric mixture of combustible gases, such as, oxygen and hydrogen, which is ignited when sufficient gases have been collected to achieve the desired explosive force in the area surrounding the drilled borehole. In another use of the present invention, the gases are not ignited but rather at least one of the generated gases are delivered by pressure into the area surrounding the drilled borehole to enhance environmental remediation processes.

Abstract: A seismic detector for boreholes is described that has an accelerometer sensor block for sensing vibrations in geologic formations of the earth. The density of the seismic detector is approximately matched to the density of the formations in which the detector is utilized. A simple compass is used to orient the seismic detector. A large surface area shoe having a radius approximately equal to the radius of the borehole in which the seismic detector is located may be pushed against the side of the borehole by actuating cylinders contained in the seismic detector. Hydraulic drive of the cylinders is provided external to the detector. By using the large surface area wall-locking shoe, force holding the seismic detector in place is distributed over a larger area of the borehole wall thereby eliminating concentrated stresses.

Abstract: A closed-cycle combustion low-frequency acoustic pulse source for use underwater. An elongated combustion chamber, having a first end and a second end and an elongated elastic sleeve, is filled with a stoichiometric mixture of oxygen and hydrogen from an electrolyzer. When the mixture is ignited at the first end of the chamber, a longitudinally traveling flame front is initiated at the first end of the chamber. The moving front results in a traveling thermal pressure pulse. The pressure pulse is communicated to the surrounding underwater medium producing a generally uni-directional acoustic pressure pulse along the longitudinal axis of the elongated chamber. An alternative embodiment utilizes an array of sources disposed along the generally horizontal longitudinal axis of the array.

Abstract: A method of and a system for remotely controlling an adjustable, electrodeless arc discharge acoustic pulse transducer for borehole and underwater operations using high-energy arc discharges to generate high power seismic and acoustic pulses capable of being easily and remotely adjusted in time duration and magnitude such that they can be customized to create waveforms of preferred shapes. The transducer has an insulating ceramic barrier which contains a biconical aperture separating two bodies of electrolyte through which the two zones of liquid make contact and electrically adjustable circuits for switching supplemental amounts of stored electrical energy into the arc discharge circuit at successively delayed time intervals to lengthen the arc discharge current pulse to create the desired waveform shape for detecting variations in the geological features of the formations being probed or for use in ocean acoustic or sonar applications.

Abstract: A piezoelectric transducer having a solid body with electrode strips either attached to the body or embedded within it. The electrodes are electrically isolated from each other on the body of the transducer and are arranged in a pattern so that they may be selectively connected to a voltage source to produce electromechanical forces within the body, thereby causing associated vibrations of the body. Initially, the electrode strips are used to polarize the transducer. During operation of the transducer as a vibration source, the electrode strips are used to connect an applied voltage having a polarity opposite to that of the polarizing voltage on one face of the body. The transducer is especially useful for producing flexural vibrations, but a number of other vibration modes of operation are possible. The transducer is operable either as a vibration source or as a sensor.

Abstract: Method and apparatus are presented for producing liquid aerosol particles of narrow size distribution by dispersing one or more droplet columns and impinging these droplets onto a vibrating cavitation surface to create a high density fountain of aerosol particles. Flash cavitation of these impinging droplets is achieved through controlled disruption on impact of the impinging liquid droplets with a vibrating surface wherein the measured size and frequency of droplets promote complete disruption of the droplets into aerosol particles with substantially no splash disruption or agglomeration thus efficiently producing small liquid aerosol particles having a narrow size dispersion range.

Abstract: A transducer is constructed of a cylindrical shell and at least one pair of piezoelectric sections. Each member of the pair of piezoelectric sections is rigidly bonded to the wall of the cylinder, in a position diametrically opposed from the other member of the pair. Operation as an acoustic source transducer is accomplished by electrically energizing each piezoelectric section in such a manner as to cause the piezelectric sections to elongate and contract, respectively out of phase with one another, along the cylinder length. This causes flexural bending of the cylinder, with the bending being asymmetrical with respect to the cylinder axis. When one pair of piezoelectric sections is used in this manner, the transducer approximates an acoustic dipole radiator, and if more than one pair is used, the transducer can be used to approximate higher order polarized acoustic radiators.

Abstract: An apparatus and method of high resolution reverse vertical seismic profile (VSP) measurements is shown. By encapsulating the seismic detector and heaters in a meltable substance (such as wax), the seismic detector can be removably secured in a borehole in a manner capable of measuring high resolution signals in the 100 to 1000 hertz range and higher. The meltable substance is selected to match the overall density of the detector package with the underground formation, yet still have relatively low melting point and rigid enough to transmit vibrations to accelerometers in the seismic detector. To minimize voids in the meltable substance upon solidification, the meltable substance is selected for minimum shrinkage, yet still having the other desirable characteristics. Heaters are arranged in the meltable substance in such a manner to allow the lowermost portion of the meltable substance to cool and solidify first.

Abstract: Various configurations of cylindrically shaped transducers are used as borehole seismic wave sources. The basic class of transducers of this invention has an outer shell that is generally cylindrical, and may be comprised sections. The shell or the sections may be pre-stressed or preformed to encourage certain bending motions. Depending on the configuration of the transducer, it approximates a monopole, dipole, or quadrupole radiator. Various actuating means, including magnetostrictive forces and piezoelectric forces, are used to drive the motions of the transducer. These transducers are especially useful for generating compressional, shear, or other elastic waves in solids. For example, in geophysical applications, the transducers are placed in boreholes for either hole-to-hole or single hole measurements.

Abstract: In a geomembrane defined impoundment, a leak is located by vessel supported means. The present invention is directed to locating the vessel so as to then locate the leak. A set of N hydrophones spaced around the impoundment detect a liquid transmitted acoustic pulse from the vessel. The vessel supports an RF transmitter which broadcasts a timing pulse. With the timing pulse, elapsed acoustic travel time is measured to define range in the liquid. The range defines an arc of a circle around a single hydrophone. Using N hydrophones, N arcs are defined on the impoundment, each centered on the respective hydrophones, to intersect at the vessel location.

Abstract: A method and apparatus for collecting measurements on the surface of the earth in a form which can be processed to obtain enhanced resolution of subsurface resistivity anomalies in the earth's geologic structure. The system of the preferred embodiment utilizes many separately acquired voltage and current measurements on the earth's surface in a superposition analysis to "synthesize" the condition whereby the many separate measurements are acquired simultaneously to give useful advantages in improved depth of investigation commonly known as focused resistivity measurements.

Abstract: A method and apparatus for producing uniform, monosize ceramic particles forming the microsize particles by vapor condensation or ultrasonic cavitation. Organometallic liquids are directed to an aerosol generator where a droplet stream is projected in free flight within a reaction chamber and a particle sorter. Through the process of sorting the droplets according to their velocity in flight, monosize droplets are collected. The particles may be reacted prior to or after sorting and collection to form the monosize ceramic particle of interest. Sintering aids are introduced into the process to produce ceramic particles capable of improved green body formation.

Abstract: For use in determing the rate of loss of liquid from an impoundment, the loss being through a leak in the impoundment and further making such measurements in the presence of surface losses due to evaporation, an apparatus is set forth which includes first and second open ended columns for receiving the impounded liquid therein. The first column is isolated while the second column is communicated near the bottom thereof with a passage into the impoundment so that its height will fall with the height of liquid in the impoundment. A measuring means is interposed betwen the two columns to measure differences in height. The two columns are equipped with baffles to suppress column height agitation. The measuring means comprises first and second communicated respectively with the first and second columns, said chambers being filled with first and second liquids which are not miscible, which differ in dielectric constant, and have different densities.