Abstract: Long-term changes in the distribution of a mineral in a subsurface deposit, due to commercial production of the mineral, are monitored by suitable instrumentation. The monitoring instrumentation is installed in combination with commercial mineral production equipment but the monitoring instrumentation is transparent to production. The monitoring instrumentation measures long-term changes in selected petrophysical attributes that are due to re-distribution of the mineral within the deposit in response to production.

Abstract: A process and device for detecting objects, in particular mines, dispersed in an area of land. The process implements a plurality of acoustic transducers. After determination of an optimal operational frequency, a brief acoustic pulse is emitted into the ground and then successive temporal reversals of signals received by the transducers focus detection on a first object. At least two transducers for which the propagation times are roughly equal are located and at least one location direction, defined as the mean perpendicular of the segment joining the at least two transducers, is determined.

Abstract: A method and apparatus for monitoring the condition of a ground anchorage including a tendon arranged in a bore in a group formation at a site is characterized by detecting the vibrational response signature of the anchorage to an impulse load. The vibrational response signature to the impulse is recorded and compared with a reference signature from which any changes in the integrity of the anchorage can be determined.

Abstract: Method and apparatus for detecting failure of tensioned reinforcements in a structure by means of a plurality of acoustic or seismic detectors disposed about the structure in a known arrangement, processing signals from the detectors to determine frequency contents and origins, and identifying simultaneous signals as due to the failure of tensioned reinforcements in the structure when they meet spectral and origin criteria.

Abstract: A vibratory compactor includes front and rear frame portions driven by a first hydraulic motor and a vibration mechanism on at least one of the frame portions also driven by a second hydraulic motor. A first sensor on the vehicle senses movement of a member on said vehicle driven by said first hydraulic motor, and sends corresponding signals to a microcontroller on the vehicle. A timing device sends timing signals to the microcontroller, which is programmed to convert the movement signals and timing signals to indicate longitudinal speed of travel of the vehicle. The microcontroller automatically turns a vibration means on the vehicle on or off depending on the speed of the vehicle. A second sensor on the vehicle sends a signal to the microcontroller indicating a reverse direction of travel of the vehicle. The microcontroller automatically coincides the direction of motion of the vibration means with the direction of travel of the vehicle.

Abstract: A method and apparatus for measuring bottom scour adjacent a foundation structure extending into the bottom of a stream of flowing water is disclosed. An elastic wave source is used for transmitting elastic waves through the water, the scour zone, and the bottom adjacent the foundation structure. The elastic waves are transmitted directly to an array of receivers and indirectly through the foundation structure to produce refracted signals that also travel to the receivers. The array of receivers are adapted for substantially vertical positioning such that a portion of the receivers will sense elastic waves that travel through the water above the scour, a portion will sense elastic waves that travel through the scour, and a portion will sense elastic waves that travel through the bottom adjacent the structure. Means are utilized for recording the time required for the elastic waves to reach each receiver to measure the depth of scour next to the foundation structure.

Abstract: A compacting machine having a vibrating drum for compaction of ground material includes a controller. The drum is moved over a segment of the ground while a shear modulus and a plastic parameter of the segment of the ground are measured. From the measurements, in particular the value of the shear modulus, values for the frequency and/or the amplitude of the vibration and/or the rolling velocity of the drum are determined. These values are used for adjusting the compacting machine. In the measurement of the shear modulus, two accelerometers are used for determining, during the passing of the segment of the ground, the acceleration of the drum in at least an essentially vertical direction. The amplitude and the phase position of the eccentric system in relation to the acceleration are determined by using, among other things, a pulse sensor. Therefrom, and from fixed data concerning the compacting machine, the shear modulus of the ground is determined by integration of state equations.

Abstract: In order to determine the seismic vulnerability of a structure, a vibration sensor is placed on each of the top surface of a layer of the structure and the ground surface near the structure so as to record vibrations. A seismic vulnerability data processor assumes a transfer function of vibration of the top surface of the layer of the structure based on a spectral ratio between the vibration recorded on the top surface of the layer of the structure and the vibration recorded on the ground surface, thereby obtaining a predominant frequency and amplification factor of vibration of the top surface of the layer of the structure. A seismic vulnerability index of the layer of the structure resulting from a deformation of the layer is obtained based on the obtained predominant frequency and amplification factor of vibration of the top surface of the layer of the structure and on the height of the layer of the structure.

Abstract: A method and apparatus for sensing one or more physical parameters, including acoustic waves having frequencies from approximately 0 Hz to 15 Hz, electromagnetic waves having frequencies from approximately 0 Hz through 35 Hz and seismic waves having frequencies from approximately 0 Hz through 15 Hz, and detecting precursor seismic activity indicated therein. Acoustic waves are sensed using an infrasonic transducer that produces an electrical signal representative of such waves. Electromagnetic waves are sensed using a suitable antenna, the antenna preferably comprising AC power lines. The antenna produces an electrical signal representative of such waves. Seismic waves are sensed using an accelerometer that produces an electrical signal representative of such waves.

Abstract: A buried pipe detection device based upon the principle of sensing of difences in the dielectric/conductive properties of the ground in the vicinity of the pipe is disclosed. Because the electrical properties of the ground directly over the buried pipe will differ from those of an area immediately adjacent to the pipe, the detection principle is embodied in a capacitor plate array that injects a low frequency sinusoidal signal into the ground and samples the injected signal from two spatially separated locations on the array. The capacitor plate array has two injector/sensor plates that form a capacitively coupled impedance bridge with the ground and a third plate to establish circuit ground. The injector/sensor plates sense changes in the ground path impedance directly beneath the plates as the array is moved along the ground. The outputs of the two sensor/injector plates are then combined differentially and are processed to provide a continuous analog or digital readout.

Abstract: A new method for pre-construction determinations of the natural frequency of damped vibrations of foundations under machinery with known vertical impact loads which will be installed on a soil base, comprising steps for impacting the soil base with a weight to create natural vibrations of said soil base, measuring the vibration responses on soil base, recording the vibration responses, conducting spectrum analyses over the range of the soil base vibration records, and, determining the dominant natural frequency of said soil base from the preceding step, which frequency is an estimate of the natural frequency of vertical damped vibrations of the machine foundation.

Abstract: A method and equipment are described for performing measurements while drilling for oil or gas, in particular VSP-measurements employing a seismic source together with sensors such as hydrophones and/or geophones connected to a memory- and calculation device for storing and processing the seismic signals. The seismic source (2) is placed at or in the vicinity of the surface of the earth whereby signals generated by the source are detected by the hydrophones (3,5) or the geophones located in the vicinity of the source (2) at the surface and in the drill string (4). The geophones or the hydrophones (5) in the drill string transmit the detected signals to a memory- and calculation unit (6) in the drill string that processes and transmits the signals completely or partly to a central data processing unit (10) on the rig (7).

Abstract: The soundness of a block-shaped structure is evaluated by disposing one set of at least two three-way sensors on a structure, measuring microtremors, determining the contribution factor of rocking vibration, which occupies part of overall vibration, based upon the results of microtremor measurement, and determining extent of rocking vibration at an arbitrary position of the block-shaped structure based upon the contribution factor. Rocking vibration becomes more prevalent as the state of support afforded by the block-shaped structure becomes more unstable. Accordingly, if rocking vibration becomes dominant and exceeds unity, this fact can be used to evaluate the soundness of the block-shaped structure to collapse.

Abstract: An object detector for detecting metallic or non-metallic objects is disclosed which comprises a sound source such as a speaker (12) for generating impulse short sound bursts. A tube (16) conducts the acoustic signal from the speaker to the ground and at least one microphone M1-M3 is utilised for detecting reflections from the ground. A reflection from a buried object is compared with a reference signal which may be obtained from another microphone M1, M2 or earlier in time from the same microphone M3. The reflected and reference signals are subtracted to provide a difference signal and a difference signal is correlated with the original acoustic signal to provide an indication of an object. Time windows may be set to enable analysis of different depths to be obtained.

Abstract: An electronic measuring instrument measures and records the acceleration frequency spectra of a multi-story building while it is excited by wind. Such frequency spectra are indicative, in part, of building structural stiffness. When a tramatic structural event occurs, such as an earthquake, an explosion, or a hurricane, changes in wind-excited frequency spectra are used to detect hidden structural damage to the building.

Abstract: A method and apparatus for the nondestructive evaluation of ferromagnetic and non-ferromagnetic materials, particularly wire ropes, cables, and strands, and pipes utilizing the magnetostrictive effect for measuring minute variations in magnetic fields and characterizing these minute variations as indicative of the acoustic/ultrasonic behavior of fractures, cracks, and other anomalies within a substance under evaluation. The apparatus and method contemplate both an active testing application, wherein a transmitting sensor generates an acoustic/ultrasonic pulse within a material through the magnetostrictive effect and a second receiving sensor detects reflected acoustic/ultrasonic waves within the material, again by the inverse magnetostrictive effect. The advantages of utilizing magnetostrictive sensors as opposed to well known piezoelectric sensors lies in the ability to generate and detect acoustic/ultrasonic waves without a direct physical or acoustical contact to the material.

Abstract: A signal processing system for determining sea floor composition based on the frequency waveform and Doppler shift transmitted from an acoustic penetrometer includes a hydrophone for receiving the penetrometer waveform. The hydrophone output is digitized and passed to a general purpose computer where it is analyzed by a signal processing program. The signal processing program performs various signal transformations to increase the quality of the input waveform and isolates a penetration event. Additionally, the input signal is converted to an equivalent velocity waveform. A curve fitting algorithm is then used to determine the points within the velocity waveform that mark the initiation and termination of the penetration event that corresponds to the impact of the penetrometer with the sea floor. Once the initiation and termination of the penetration event are known, the velocity waveform is numerically integrated between those two points.

Abstract: A acoustic-penetrometer probe and method for determining the presence of materials in a region proximate the penetrometer probe through measurement of reflected acoustic waves, with the probe having a driving head on one end to permit forcing the driving head into the soil, with the probe including an acoustic generator mounted in the probe for generating a below-ground acoustic wave that normally travels away from the acoustic generator, and an acoustic detector located in the probe to measure acoustic waves reflected from objects or materials located proximate the probe to thereby provide a user with information on the presence of materials proximate a radial region located around the probe.

Abstract: Methods and apparatus for determining whether soil is satisfactorily compacted. An operator delivers impact energy to the soil, and the amount of impact energy transmitted through the soil is repeatedly sensed and stored. A modelling formula, which approximates the variation of the stored amounts of impact energy, is used to generate current and target values for the level of compaction; if the current value equals or exceeds the target value, the soil is considered to be satisfactorily compacted.

Abstract: A method and apparatus for determining the setting time of a cement slurry. An acoustic shear wave signal is generated and introduced at a first location in the slurry. The signal is monitored at a second location for direct transmission of the shear wave signal. The time of first detection is determined at the second location which is taken as the setting time of the slurry.

Abstract: Methods and apparatus for monitoring the compaction of soil material in a defined region include hammer structure for impacting soil material in the defined region, a sensor for disposition at the bottom of the defined region the includes a transducer for developing an electric signal in response to energy transmitted through soil material from the hammer structure, and a control module responsive to electric signals from the sensor for providing an indication of the quality of compaction of soil material in the defined region.

Abstract: Methods and apparatuses for measuring ultrasonic velocities in materials are disclosed which, in one embodiment, include such methods and apparatuses for triaxial tests of low permeability rock samples, the apparatus including top and bottom end caps for mounting to a sample to be tested, each end cap having an ultrasonic transducer mounted therein for disposition in contact with the material to be tested for measuring the velocities of ultrasonic waves through the material. In another embodiment, at least one end cap having channels and a sensor for sensing changes in sample pore pressure is disclosed. In another aspect, a pressure generator or microaccumulator for changing the amount of a pore pressure fluid in the channels, thereby changing sample water content and making possible an efficient multistage test is disclosed. In another embodiment an end cap for such measurements is disclosed.

Abstract: An apparatus for monitoring a vibrating structure, such as a bridge, uses multiple motion sensors spaced along the structure, each of which produces an analog raw data signal which is then filtered in anti-aliasing filters to remove substantially all frequency components of the signal above a selected cutoff frequency, f.sub.co. The filter outputs are connected to addressed inputs of an analog multiplexer which then multiplexes the signals in response to a channel address clock which repeatedly generates a sequence of channel addresses to scan the data input channels at the multiplexer corresponding to the addresses in the sequence. The complete sequence of addresses is repeated at a frequency of at least twice the cutoff frequency to obtain substantially simultaneous samples from the sensors so that data from different sensors may be correlated. The multiplexed signal is then converted to digital form and stored.

Abstract: The present invention features an apparatus and method for impact-echo testing of structures in situ, in the field. The impact-echo testing method provides a non-invasive, non-destructive way of determining the defects in the structure. The method is both uniform and reliable, the test procedure being substantially identical every time. The apparatus of the invention comprises a portable, hand-held unit having a plurality of impactors disposed therein. The plurality of impactors comprise a number of differently weighted spheres that are each designed to impart a different impact energy into the structure to be tested. Each sphere is disposed on a distal end of a spring-steel rod. A particular weighted sphere is chosen by a selector disposed on the testing unit. The sphere is withdrawn from the rest position by a pair of jaws to a given height above the structure.

Abstract: Methods and apparatus for monitoring the compaction of backfill material in an excavation include hammer structure for impacting backfill material in the excavation, a sensor module for disposition at the bottom of the excavation to be backfilled that includes a transducer for developing an electric signal in response to energy transmitted through backfill material from the hammer structure, and a control module responsive to electric signals from the sensor module for providing an indication of the quality of compaction of backfill material in the excavation.

Abstract: A loose rock detector comprises an impact tool for hitting the rock face, sensors for detecting acoustic, rock motion and/or impact force signals generated by movement of the impact tool against the face of the rock, a data processor responsive to the sensors for correlating the above signals in the time and/or frequency domain against predetermined relationships to detect loose rocks and to assess mass and degree of looseness of the rock, and a display unit for displaying the results of the correlation.

Abstract: A method is disclosed for detecting the presence or absence of anisotropy in a subterranean geological formation and for determining its orientation. In a first preferred embodiment, the method utilizes a seismic source which generates circularly polarized shear waves and directs them to a target formation. These waves undergo wave splitting on encountering anisotropic conditions and the resulting components are linearly polarized and are reflected to the surface or to a bore hole where they are detected by receivers. The reflected arrivals are then analyzed to detect the presence and orientation of the linearly polarized arrivals as is known in the prior art. In an alternative preferred embodiment, the use of a circularly polarized source is simulated by generating two orthogonal waves linearly polarized 90.degree. out of phase with respect to each other.

Abstract: A method and apparatus for monitoring the structural acoustic signature of a structural member in response to a transient load, corresponding to detected vibration frequencies transmitted by the structural member including the fundamental and harmonic frequencies of the structural member, to determine changes in structural integrity and to determine the nature and type of transient loads. The structural acoustic signature of the structural member in a first condition in response to a first transient load is compared to a structural acoustic signature from a second transient load whereby differences in the signatures correspond to the occurrence of changes in the elastic qualities or condition of the structural member. The signatures are preferably evaluated in the frequency domain. The nature and type of transient load can be determined by evaluating the waveform shape of a structural member in response to the unknown load against a history of waveform shapes corresponding to known loads.

Abstract: The present invention relates generally to a method for determining seismic velocities and more particularly to a method and system for objectively determining seismic velocities from samples of the earth's subterranean formation. Additionally, the present invention provides a method for obtaining a measure of the variation of seismic velocities of propagation with pressure.

Abstract: The surface of a cement intimate mixture filled portion in a building is tapped by a hammer, and a tapping sound thus generated is received by a micropone and converted to an electrical signal. The electrical signal representing the attenuation characteristic, which is different depending on the presence or absence of a defective unfilled portion in the cement filled portion, is sampled to obtain a maximum peak value and/or an integrated value. The maximum peak value and/or the integrated value is compared with a reference value to decide the presence or absence of a defect in the cement filled portion.

Abstract: A novel method for detecting and measuring elastic anisotropy in a sample of the earth's formations is provided. A dyad of time series signal representative of the sample's response to imparted shear waves is recorded. The dyad of time series signals can then be processed to detect and measure elastic anisotropy in the sample. More particularly, the dyad of time series signals are collected by imparting shear waves having first and second polarizations into the samples with a shear wave transducer and recording the sample's response to each of the imparted shear waves by shear wave transducers having first and second polarizations. In one embodiment of the invention, the dyad of time series signals can be diagonalized to detect and measure elastic anisotropy in the sample. In another embodiment, the dyad of time series signals can be processed for a plurality of rotation angles and the resulting rotated dyad of time series signals can be displayed to detect and measure elastic anisotropy in the sample.

Abstract: A method and apparatus for monitoring the structural acoustic signature of a structural member in response to a transient load, corresponding to detected vibration frequencies transmitted by the structural member including the fundamental and harmonic frequencies of the structural member, to determine changes in structural integrity and to determine the nature and type of transient loads. The structural acoustic signature of the structural member in a first condition in response to a first transient load is compared to a structural acoustic signature from a second transient load whereby differences in the signatures correspond to the occurrence of changes in the elastic qualities or condition of the structural member. The signatures are preferably evaluated in the frequency domain. The nature and type of transient load can be determined by evaluating the waveform shape of a structural member in response to the unknown load against a history of waveform shapes corresponding to known laods.

Abstract: A method and apparatus for nondestructive evaluation of a structure is disclosed. Resonant audio frequency vibrations are excited in the structure to be evaluated and the vibrations are measured and characterized to obtain information about the structure. The vibrations are measured and characterized by reflecting a laser beam from the vibrating structure and directing a substantial portion of the reflected beam back into the laser device used to produce the beam which device is capable of producing an electric signal containing information about the vibration.

Abstract: A method and apparatus for measuring the motion of tall structures, particularly offshore platforms. The method comprises disposing a number of accelerometer packages in a tubular member attached to a vertical or near vertical member of the structure. Each package contains three accelerometers having their axes dipsosed in an orthogonal arrangement. The apparatus includes means for installing and removing a plurality of packages from tubular members or chutes that are permanently attached to the structure.

Abstract: A vibration sensor for measuring the flow of vibrational energy through a structure comprises four accelerometers (24-27) placed in cruciform arrangement on the surface of the structure. The signals from the accelerometers are processed in pairs using sum/difference amplifiers (36-40) to give two rotational (41, 42) and one translational (43) acceleration signal. The acceleration signals are frequency modulated (46-48) by as local oscillator (53) of preselected frequency, low-pass filtered (62-64) and the rotational acceleration signals (68, 70) then multiplied (72, 73) in phase quadrature (54) with the translational acceleration signal (69). The DC components of the resulting signals (76) are proportional to the time-average vibrational power flow. Knowledge of the flow paths facilitates the design of the structure to minimize effects of unwanted vibrations.

Abstract: The azimuthal direction of the mechanical anisotropy of a material is measured by using a first transducer to transmit shear acoustic energy through the material and a second transducer, cross-polarized with respect to the first transducer, to receive the shear acoustic energy after it has traveled through the material. Amplitude and phase of the cross-polarized shear acoustic energy are measured as a function of the azimuthal rotation of the shear acoustic energy transducers with respect to the material.

Abstract: A mechanical seismic instrument for recording relative horizontal displacements between the base and foundation of base-isolated buildings or other large structures during earthquakes. A rigid tripod-like arm is connected to the base of the structure; on the other end of the arm is a marking stylus. A record plate is connected to the foundation. When base and foundation move relative to one another, the stylus scribes a record trace on the record plate. Arm and record plate are mounted respectively on mounting plates which are connected and covered by a flexible enclosure. Timing marks on the record trace may be made by striking devices which tap against the shank of the stylus.

Abstract: The present invention provides a method which avoids the expense and danger of previous methods used to discover gas contained in geological formations to be mined. Specifically, it has been found that increasing gas contents of evaporite samples emit increasing levels of sound when dissolved in water. By recording the sounds given off by small grab samples taken from within the mine and from the specific formation to be mined, the volume of gas in the sample can be ascertained and gas liberation during mining operations may be predicted. The method comprises the steps of: obtaining a sample; placing it into water and placing the water and sample into a sound-proof chamber; recording the acoustic emissions given off as the sample dissolves; using the recorded acoustic emissions to determine the presence and volume of gas in the sample; and predicting the volume of gas in the evaporite formation to be mined.

Abstract: A mining machine having means for sensing property variations of the materials associated with a seam of a mine. The machine comprises a member (4) which rotates about an axis A. The rotatable member mounts at least one cutter 6 spaced from the axis for cutting material from the seam. A rod (10) carried by the rotatable member is held in releasable engagement with the cutter. The rod extends to the axis of the rotatable member to conduct to the axis, strain waves which are induced by variations in cutter vibration as the cutter encounters property variations of the materials associated with the seam. A transducer (24,54) is located at the axis of the rotatable member in communication with the rod to convert the strain waves in the rod to electric signals which may be recorded or visually displayed.

Abstract: Acoustic energy anisotropy is measured in a core sample from a subterranean formation. The core sample is shaped by having its outer surface cut to provide a plurality of pairs of parallel, planar outer surfaces about the length of the core sample. A pair of planar transducers are successively placed in contact with each of the pairs of parallel, planar outer surfaces, one of the transducers being a transmitting transducer and the other being a receiving transducer. Compressional or shear acoustic energy is transmitted through the core sample in the aximuthal directions that are perpendicular to each of the pairs of parallel, planar outer surfaces of the core sample. Any differences in travel time, attenuation, waveform or other acoustic properties for the acoustic energy transmissions in the plurality of differing azimuthal directions are a measure of the compressional or shear acoustic energy anisotropy of the subsurface formation.

Abstract: Vertical shear acoustic energy anisotropy of a subterranean formation is measured from a core sample of such formation. The core sample is shaped by having its outer surface cut to provide a pair of flat or planar surfaces along parallel spaced-apart planes. A pair of planar shear transducers are placed in contact with the pair of planar outer surfaces, one of the transducers being a transmitting transducer and the other being a receiving transducer. Shear acoustic energy is transmitted through the core sample in a basically elliptical pattern having an azimuthal direction within a plane parallel to the planar outer surfaces of the core sample. Any differences in travel time, attenuation, waveform or other acoustic properties for the acoustic energy transmissions in a plurality of differing azimuthal directions are a measure of the shear acoustic energy anisotropy of the subsurface formation.

Abstract: A rock detachment evaluation device (10) having an energy transducer unit 1) for sensing vibrations imparted to a subject rock (172) for converting the sensed vibrations into electrical signals, a low band pass filter unit (12) for receiving the electrical signal and transmitting only a low frequency segment thereof, a high band pass filter unit (13) for receiving the electrical signals and for transmitting only a high frequency segment thereof, a comparison unit (14) for receiving the low frequency and high frequency signals and for determining the difference in power between the signals, and a display unit (16) for displaying indicia of the difference, which provides a quantitative measure of rock detachment.

Abstract: A fluid chamber assembly having an improved shape to enhance the reception of the first arrival of the signal from the transmitter transducer which has passed through the cement or fluid sample within the fluid chamber assembly and an improved sealing arrangement for the fluid chamber assembly.

Abstract: The present invention relates to a method for acoustic testing of multiple segment complex structures for detecting changes in the integrity of such structures to anticipate failure. The method of the present invention in its simplest form requires providing each segment of a complex multiple segment structure with at least one acoustic sensor, recording the intensity and frequency distribution of the acoustic waves sensed by such acoustic sensor; and finally comparing the acoustic waves that are sensed either against a standard, over time, and/or from one segment of the complex multiple segment structure to another segment of the complex multiple segment structure.

Abstract: The invention refers to a procedure and a device for measuring the degree of compaction attained when compacting a foundation by means of a vibrating compaction tool. The movement of that part of the compaction tool which rests on the foundation is sensed and analyzed. The time interval elapsing between successive passages of the movement signal through the zero point or other reference level is measured. Alternatively, the ratio between the absolute values of the extreme positive and extreme negative values of the motion in relation to the said level is also measured. By means of the relative magnitudes of these time intervals and amplitude relationships respectively a quantity is formed which comprises a measure of the degree of compaction of the foundation.

Abstract: Method and apparatus for measuring the acoustic impedance of a surface in which the surface is used to enclose one end of the chamber of a Helmholz resonator. Acoustic waves are generated in the neck of the resonator by a piston driven by a variable speed motor through a cam assembly. The acoustic waves are measured in the chamber and the frequency of the generated acoustic waves is measured by an optical device. These measurements are used to compute the compliance and conductance of the chamber and surface combined. The same procedure is followed with a calibration plate having infinite acoustic impedance enclosing the chamber of the resonator to compute the compliance and conductance of the chamber alone. Then by subtracting, the compliance and conductance for the surface is obtained.

Abstract: A quasi-static cone penetrometer for subsoil investigation by simultaneously generating three sets of data, namely cone tip penetration resistance, sleeve friction resistance, and acoustical information, all as a function of depth. The penetrometer has a substantially smooth cylindrical outer surface terminating in a cone tip. The lower portion of the smooth cylindrical outer surface is provided by a friction sleeve immediately above the cone tip insulated from it by acoustic attenuation means. A microphone in the tip (or elsewhere in the penetrometer) is responsive to acoustical input generated, for example, by the tip moving through the soil, and sound barrier means holds said microphone firmly in place. The sound barrier means, the acoustic attenuation means, and the acoustical dampening means substantially isolate the microphone from the core ring and from the friction sleeve. A tip load cell is joined to the cone tip and insulated from it acoustically by acoustical-dampening means.

Abstract: A system for measuring ultrasonic (50 Khz-10 Mhz) velocity and attenuation in core samples employs transmitting and receiving transducers for generating and receiving ultrasonic energy in a core sample. The transducer and core sample are contained in a high pressure cell. The transducers are isolated from the high pressure of the cell by suitable housings, allowing the transducers to operate at ambient pressure.

Abstract: A harmonic oscillator and motion detection system for use in measuring dynamic elastic constants of rock material samples includes a pair of masses vertically suspended from a support position by a pair of wires. At least one mass is driven by a permanent magnet with the driving coil positioned in the air gap to the magnet. The rock sample is horizontally positioned between the pair of masses such that the rock sample acts as a spring element connecting the masses, thereby forming the simple harmonic oscillator. The motion detection system includes a pair of coil-magnets mounted to each mass for use in determining the amplitude and phase of the motion of the pair of masses.

Abstract: The invention relates to a device for acoustically controlling the setting and hardening characteristics of a material such as cement. This device comprises a cell body defining a cylindrical body, or measuring chamber, which contains a receptacle adapted to receive the material to be tested. The measuring chamber is extended by its two ends by two cylindrical passages coaxial to said chamber, which comprise each a threaded portion and are associated to sealing means; said cell body further includes two electro-acoustic transducers which are arranged at mutually opposed locations and are facing each other. The novel device is adapted to be used for determining and controlling the setting, hardening and mechanical strength characteristics of cement or similar material under conditions of high pressure and elevated temperatures.