Abstract: A seismic wave source and sensing system coupled to the surface of an elastic wave propagation medium has a seismic wave source transducer having a preferred axis of vibration oriented horizontally on the surface of the elastic wave propagation medium. A seismic wave sensing transducer has a preferred axis of vibration response oriented horizontally on the surface of said elastic wave propagation medium such that said sensing transducer is capable of detecting dynamic particle motions and displacements of SH waves. An arrangement of the source and sensing transducers is provided on the surface of the elastic wave propagation medium. A recording system capable of acquiring and storing reflected SH wave signals detected by the sensing transducer, wherein the recorded signals represent reflections from contrasting physical properties within the elastic wave propagation medium to provide preferential detection of elongate subsurface targets such as utility pipes, conduits, and other similar object.

Abstract: A vibration sensor system for contacting the surface of a solid medium for detecting horizontally polarized shear waves and compressional waves. At least two contact points interface between a vibration sensor array and the solid medium to provide uninterrupted contact with the medium during detection of dynamic motions in the medium. A single vibration sensor is mounted on at least two adjacent contact points to convert detected dynamic motions to corresponding electrical signals. The single vibration sensor mounted on the two adjacent contact points forms a sub-array. The vibration sensor system has at least two sub-arrays. A conditioning and combining member treats sensor electrical signals from at least two sub-arrays to form a composite output signal for the system.

Abstract: A vibration sensor system for contacting the surface of a solid medium for detecting horizontally polarized shear waves and compressional waves. At least two contact points interface between a vibration sensor array and the solid medium to provide uninterrupted contact with the medium during detection of dynamic motions in the medium. A single vibration sensor is mounted on at least two adjacent contact points to convert detected dynamic motions to corresponding electrical signals. The single vibration sensor mounted on the two adjacent contact points forms a sub-array. The vibration sensor system has at least two sub-arrays. A conditioning and combining member treats sensor electrical signals from at least two sub-arrays to form a composite output signal for the system.

Abstract: A vibration source (10) includes an armature bar (12) having a major length dimension, and a driver (20A) positioned about the armature bar. The driver (20A) is movably coupled to the armature bar (12), and includes an electromagnet (40). During operation the electromagnet (40) is activated such that the driver (20A) moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar. A described method for generating a vibratory signal in an object includes positioning the vibration source (10) in an opening of the object, coupling the armature bar (12) to a surface of the object within the opening, and activating the electromagnet (40) of the driver (20A) such that the driver moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar and the object.

Abstract: A method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.

Abstract: A vibration source (10) includes an armature bar (12) having a major length dimension, and a driver (20A) positioned about the armature bar. The driver (20A) is movably coupled to the armature bar (12), and includes an electromagnet (40). During operation the electromagnet (40) is activated such that the driver (20A) moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar. A described method for generating a vibratory signal in an object includes positioning the vibration source (10) in an opening of the object, coupling the armature bar (12) to a surface of the object within the opening, and activating the electromagnet (40) of the driver (20A) such that the driver moves with respect to the armature bar (12) and a vibratory signal is generated in the armature bar and the object.

Abstract: A gas energy meter that acquires the data and performs the processing for an inferential determination of one or more gas properties, such as heating value, molecular weight, or density. The meter has a sensor module that acquires temperature, pressure, CO2, and speed of sound data. Data is acquired at two different states of the gas, which eliminates the need to determine the concentration of nitrogen in the gas. A processing module receives this data and uses it to perform a “two-state” inferential algorithm.

Abstract: A method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.

Abstract: A method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.

Abstract: A method, used in connection with a pulse-echo type sensor for determining the speed of sound in a gas, for improving the accuracy of speed of sound measurements. The sensor operates on the principle that speed of sound can be derived from the difference between the two-way travel time of signals reflected from two different target faces of the sensor. This time difference is derived by computing the cross correlation between the two reflections. The cross correlation function may be fitted to a parabola whose vertex represents the optimum time coordinate of the coherence peak, thereby providing an accurate measure of the two-way time diffference.

Abstract: A method of indirectly measuring the diluent (nitrogen and carbon dioxide) concentrations in a natural gas mixture. The molecular weight of the gas is modeled as a function of the speed of sound in the gas, the diluent concentrations in the gas, and constant values, resulting in a model equation. A set of reference gas mixtures with known molecular weights and diluent concentrations is used to calculate the constant values. For the gas in question, if the speed of sound in the gas is measured at three states, the three resulting expressions of molecular weight can be solved for the nitrogen and carbon dioxide concentrations in the gas mixture.

Abstract: A gas sensor, whose chamber uses filters and choppers in either a semicircular geometry or annular geometry, and incorporates separate infrared radiation filters and optical choppers. This configuration facilitates the use of a single infrared radiation source and a single detector for infrared measurements at two wavelengths, such that measurement errors may be compensated.

Abstract: A composite piezoelectric transducer, whose piezoeletric element is a “ribbon wound” film of piezolectric material. As the film is excited, it expands and contracts, which results in expansion and contraction of the diameter of the entire ribbon winding. This is accompanied by expansion and contraction of the thickness of the ribbon winding, such that the sound radiating plate may be placed on the side of the winding.

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 method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.

Abstract: A column assembly for use in conjunction with a test machine, for inducing high-cycle fatigue (at kilohertz vibration rates) in a specimen of a material under test. The column assembly has isolation masses, a specimen grip, and two actuators, the latter for imparting dynamic forces to the test specimen. The actuators are arranged on the column assembly asymmetrically relative to the test specimen.

Abstract: A method of indirectly measuring the diluent (nitrogen and carbon dioxide) concentrations in a natural gas mixture. The molecular weight of the gas is modeled as a function of the speed of sound in the gas, the diluent concentrations in the gas, and constant values, resulting in a model equation. A set of reference gas mixtures with known molecular weights and diluent concentrations is used to calculate the constant values. For the gas in question, if the speed of sound in the gas is measured at three states, the three resulting expressions of molecular weight can be solved for the nitrogen and carbon dioxide concentrations in the gas mixture.

Abstract: A gas sensor, whose chamber uses filters and choppers in either a semicircular geometry or annular geometry, and incorporates separate infrared radiation filters and optical choppers. This configuration facilitates the use of a single infrared radiation source and a single detector for infrared measurements at two wavelengths, such that measurement errors may be compensated.

Abstract: A composite piezoelectric transducer, whose piezoeletric element is a “ribbon wound” film of piezolectric material. As the film is excited, it expands and contracts, which results in expansion and contraction of the diameter of the entire ribbon winding. This is accompanied by expansion and contraction of the thickness of the ribbon winding, such that the sound radiating plate may be placed on the side of the winding.