Abstract: An apparatus 10 is provided that measures the speed of sound propagating in a multiphase mixture to determine parameters, such as mixture quality, particle size, vapor/mass ratio, liquid/vapor ratio, mass flow rate, enthalpy and volumetric flow rate of the flow in a pipe or unconfined space, for example, using acoustic and/or dynamic pressures. The apparatus includes a pair of ultrasonic transducers disposed axially along the pipe for measuring the transit time of an ultrasonic signal to propagate from one ultrasonic transducer to the other ultrasonic transducer. A signal process, responsive to said transit time signal, provides a signal representative of the speed of sound of the mixture. An SOS processing unit then provides an output signal indicative of at least one parameter of the mixture flowing through the pipe. The frequency of the ultrasonic signal is sufficiently low to minimize scatter from particle/liquid within the mixture.

Abstract: Fiber optic particle detector for measurements in a fluid flow, comprising an optical fiber (2,3,12) being acoustically coupled to a mechanical element (11,13,14) adapted to be acoustically coupled to the flow, a fiber optic interferometer (54,56) and a light source (12,51,55) providing light in said optical fiber.

Abstract: A plurality of quartz crystal resonators having different resonance frequencies are connected in parallel. A combined admittance of the resonators is measured. Equivalent circuit constants of all the resonators are obtained by a method of least squares from admittance characteristics. A change in the resonance frequency is measured and mass of a substance adsorbed to a piezoelectric transducer is calculated.

Abstract: An apparatus and method is described for measuring properties of bubbles from which certain physical characteristics of the liquid in which the bubbles are generated can be determined. The evolution of a bubble includes (1) formation and growth at a nozzle disposed within the liquid through which a gas is flowed, or formation and growth as a result of cavitation in the liquid from the application of focused acoustic energy to a location within the liquid; (2) detachment and resonance; and (3) rise towards terminal velocity. Measurements of the resonance frequency, the shape oscillation frequency and the terminal velocity of the bubble allow the determination of the density and surface tension of the liquid and the radius of the bubble.

Abstract: The invention provides systems, methods and apparatus for processing delicate parts within a process tank such as an ultrasonic tank. Typically, one or more transducers connect to the tank and respond to drive signals from a generator to produce ultrasound within process liquid within the tank.

Abstract: The present invention relates to remotely determining local physical parameters in a fluid-filled cavity (e.g. heart cavities, blood vessels, industrial container) by means of ultrasound waves and encapsulated or stabilised gas bubbles. A measuring method, a method of diagnostic ultrasound of the same and an apparatus for remotely determining ambient physical local parameters of a fluid-filled cavity are disclosed.

Abstract: An ultrasound inspection apparatus particularly adapted to examine containers (sealed or unsealed) containing a liquid or solid bulk material. The apparatus has an overall configuration of a hand held pistol with a front transducer contact surface that is positioned against a front wall of the container. An ultrasound pulse is transmitted from the apparatus to be reflected from a back wall of a container being investigated. The received echo pulse is converted to a digital waveform. The waveform is analyzed relative to temperature, travel distance of the pulse(s), and time of travel to ascertain characteristics of the liquid or other materials and to provide identification of the same.

Abstract: A monitoring apparatus useful in detecting viability of biological cells. A substrate defines a microscopic chamber. One or more microcantilevers extend from the substrate into the chamber. A detector is operatively connected to the microcantilevers for sensing a state of deformation thereof. On each microcantilevers is deposited a layer of an environmentally sensitive hydrogel polymer having a configuration changing in accordance with presence of an environmental parameter.

Abstract: A non-contact method for measuring viscosity and surface tension information of a liquid in a first liquid containment structure. The steps of the method include oscillating a free surface of the liquid in the liquid containment structure; detecting wave characteristics of the oscillating free surface; and analyzing the wave characteristics. The oscillating step may be performed by propagating an acoustic wave from an acoustic wave emitter, through said liquid containment structure, towards the free surface. The detecting step may be performed by delivering a series of acoustic pulses at the free surface and detecting acoustic reflections from the free surface as the oscillating free surface relaxes. The analyzing step can be performed by comparing the wave characteristics with a candidate liquid wave characteristics. Prior knowledge and behavior of the selected candidate liquid can thus be imputed to the source or sample liquid. The sample liquid can be one of photoresist, solder or a biological compound.

Abstract: A method of using ultrasonic reflectance to characterize physical properties of fluids, particularly food solutions. In general, the method comprises the steps of: (a) generating longitudinal ultrasonic waves, (b) coupling the transducer to the fluid being investigated, (c) detecting the reflected longitudinal waves, and (d) determining the physical property of interest by correlating certain characteristics of the reflected ultrasonic waves with the physical property being measured. A particular aspect of the invention is a self-calibrating ultrasonic device useful as a solids concentration sensor and/or a dissolution/precipitation sensor. Self calibration is accomplished via a twin delay line. The invention is particularly useful as an on-line sensor in the processing of food solutions such as milk, ketchup, syrup, chocolate and other confectionary.

Abstract: Described is a downhole apparatus for detecting and removing deposits from a surface exposed to wellbore fluids. The apparatus can monitor the rate of deposition and subsequently remove the deposited material. The combination of detection apparatus and removal apparatus provides a downhole instrument with self-cleaning operation mode.

Abstract: Described is an apparatus for detecting and removing deposits from a surface exposed to wellbore fluids. The apparatus can monitor the rate of deposition and subsequently remove the deposited material. The combination of detection apparatus and removal apparatus provides an instrument with self-cleaning operation mode.

Abstract: A method and device for monitoring and controlling a pharmaceutical, chemical or food process, in which the biological activity and/or the bio-mass of micro-organisms in the process is monitored, and in which the state of the process is detected by monitoring viscosity and/or aggregate size and/or content of a dispersion of proteins, crystalline particles or fat droplets that are processed, respectively. The micro-organisms and/or bio-molecules produced in the process, and the proteins, crystals particles or fat droplets being processed are monitored by means of acoustic spectroscopy.

Abstract: A method and device for monitoring and controlling a pharmaceutical, chemical or food process, in which the biological activity and/or the bio-mass of micro-organisms in the process is monitored, and in which the state of the process is detected by monitoring viscosity and/or aggregate size and/or content of a dispersion of proteins, crystalline particles or fat droplets that are processed, respectively. The micro-organisms and/or bio-molecules produced in the process, and the proteins, crystals particles or fat droplets being processed are monitored by means of acoustic spectroscopy.

Abstract: The present invention relates to physical chemistry and can be used for a quality test of liquids, in particular, multi-component liquid products, to ascertain the conformity of various process liquids, pharmaceutical preparations, foodstuffs, biological liquids to standard in pharmacology, food processing and chemical industries, and in medical diagnostics. The method of invention enables determining of the mechanical impedance within a drop (1) of test liquid having a specified volume, in the preferred embodiment, 5 mcl, placed on the surface of a piezoelectric resonator (3) of ultrasound frequencies, which provides for excitation of shear modes within drop (1) while it is drying up. The obtained time dependence of the mechanical impedance of drop (1) is used as the information parameter.

Abstract: An analytical apparatus, such as a quartz crystal microbalance, comprises a piezoelectric sensor and an oscillator circuit, coupled to the sensor, to oscillate at a frequency substantially determined by a resonant frequency of the sensor, and to provide an output signal at the oscillator frequency at an output. The oscillator circuit maintains a substantially constant drive signal to the piezoelectric sensor by an AGC (33) within a feedback loop of the oscillator. The gain control signal is used as an indication of the Q of the piezoelectric sensor. The drive signal to the sensor is made substantially sinusoidal by ensuring that all the elements in the feedback loop providing signal gain and attenuation are configured to operate in a substantially linear mode.

Abstract: An apparatus for use in characterising liquids by obtaining a fingerprint of the liquid. This allows one to measure a property of a liquid, and thereby distinguish between liquids. The apparatus comprises means for directing acoustic energy at a sample of the liquid, which is preferably in the form of a drop, and means for deriving a signal related to the interaction of the acoustic energy with the liquid sample. The drop may change in volume or shape during the measurements, to derive additional properties of the liquid. The apparatus and method of the invention are used in distinguishing and analysing a variety of liquid samples.

Abstract: A method and apparatus for in-situ characterization of downhole fluids in a wellbore using ultrasonic acoustic signals. Measurements of the speed of sound, attenuation of the signal, and acoustic back-scattering are used to provide qualitative and quantitative data as to the composition, nature of solid particulates, compressibility, bubble point, and the oil/water ratio of the fluid. The tool generally comprises three sets of acoustic transducers mounted perpendicular to the direction of the flow. These transducers are capable of operating at different frequencies so that the spectrum of the acoustic signal can be optimized. The apparatus is capable of operating downhole to provide real time information as to conditions in the well.

Abstract: A transducer-based sensor system including a first transducer system and a second transducer system spaced from the first transducer system so as to define a sample area between the first transducer system and the second transducer system where the first transducer system and second transducer system are collectively configured to transmit surface acoustic waves in multiple directions through the sample area and receive such surface acoustic waves.

Abstract: The present invention relates to physical chemistry and can be used for a quality test of liquids, in particular, multi-component liquid products, to ascertain the conformity of various process liquids, pharmaceutical preparations, foodstuffs, biological liquids to standard in pharmacology, food processing and chemical industries, and in medical diagnostics. The method of invention enables determining of the mechanical impedance within a drop (1) of test liquid having a specified volume, in the preferred embodiment, 5 mcl, placed on the surface of a piezoelectric resonator (3) of ultrasound frequencies, which provides for excitation of shear modes within drop (1) while it is drying up. The obtained time dependence of the mechanical impedance of drop (1) is used as the information parameter.

Abstract: An arrangement for measuring the carbon content of fly ash consisting of a modified coaxial resonator including an elongated arch-shaped member and an elongated conductor mounted coaxially therein and a generator for generating vibrations of variable frequency therebetween and a device for measuring attenuations in the vibrations for deriving a measure of the carbon content of ash moving between the arch-shaped member and the elongated member.

Abstract: A system and technique for determining fluid properties includes an ultrasonic transducer 30 on a first surface 42 of a solid member 40. An opposed second surface 44 of the member 40 is in contact with a fluid 25 to be monitored. A longitudinal ultrasonic pulse is delivered through the solid member, and a multiplicity of pulse echoes caused by reflections of the ultrasonic pulse between the solid-fluid interface and the transducer-solid interface are detected and processed by a processing apparatus 22. The apparatus 22 determines the decay rate of the detected echo amplitude as a function of echo number and compares this value to a calibrated decay rate to determine an acoustic property of the fluid. The speed of ultrasound in the fluid is also determined and the fluid density is determined as a function of the speed of ultrasound and the determined acoustic property.

Abstract: In an improved uncoated microcantilever detector, the sample sites are placed on a separate semi-conducting substrate and the microcantilever element detects and measures the changes before and after a chemical interaction or hybridization of the sites by sensing differences of phase angle between an alternating voltage applied to the microcantilever element and vibration of the microcantilever element. In another embodiment of the invention, multiple sample sites are on a sample array wherein an array of microcantilever elements detect and measure the change before and after chemical interactions or hybridizations of the sample sites.

Abstract: A bubble detector utilizes an ultrasonic transducer to sample bubbles as they pass the transducer. The envelope of the return signal is analyzed to determine the volume of each sampled bubble. If the total volume of bubbles sampled within a certain period of time exceeds a desired maximum volume, the bubble detector may initiate a system shut down. A bubble detector can be evaluated or calibrated by introducing bubbles into a conduit, detecting the bubbles introduced into the conduit using visual inspection or a bubble detector of known resolution and comparing the results with the examination of a bubble detector under evaluation.

Abstract: An improved photoacoustic vessel and method of photoacoustic analysis. The photoacoustic sample vessel comprises an acoustic detector, an acoustic couplant, and an acoustic coupler having a chamber for holding the acoustic couplant and a sample. The acoustic couplant is selected from the group consisting of liquid, solid, and combinations thereof. Passing electromagnetic energy through the sample generates an acoustic signal within the sample, whereby the acoustic signal propagates through the sample to and through the acoustic couplant to the acoustic detector.

Abstract: An apparatus and method for determining the density and fluid-type of a fluid flowing in a capillary tube, the velocity and viscosity of a blood sample flowing in a capillary tube, the erythrocyte sedimentation rate (ESR) of a blood sample after flow has been brought to an abrupt stop in a capillary tube, and/or the zeta sedimentation rate (ZSR) of a blood sample after flow has been brought to an abrupt stop in a capillary tube. These measurements are accomplished by directing a waveform pulse, such as an ultrasound pulse, at a pre-determined frequency transversely across the capillary tube and sample fluid, and by determining the flight of time of the pulse through the capillary tube and sample fluid and/or the Doppler shift of the echo signals reflecting off cells moving forwardly or transversely within a flowing, or stationary, blood sample.

Abstract: An apparatus to normalize a flow rate of a fluid in a main flow channel is provided. The apparatus uses a movable member, such as a flexible membrane disposed for reciprocating displacement, to produce a constant dither flow of the fluid that is independent of fluid composition. This dither flow generates a signal output from a normalizing flow sensor that both represents a characteristic property of the fluid and a flow rate calibration factor. A similar apparatus to determine the characteristic property or flow rate calibration factor is also provided. The devices disclosed may be used in numerous industrial, process, and medical flow system applications for normalization of flow sensors and to derive other properties of a fluid.

Abstract: The present invention relates to a method and apparatus of determining the rheological properties of a polymer flowing in a conduit. The invention provides a method of characterising a polymer under test, comprising: Detecting acoustic emissions from said polymer flowing in a conduit to provide acoustic emission data, comparing the acoustic emissions data obtained against acoustic emission data from a polymer, or a series of polymers, of known characteristics, and thereby characteristing the polymer.

Abstract: An apparatus for noninvasively monitoring the flow and/or the composition of a flowing liquid using ultrasound is described. The position of the resonance peaks for a fluid excited by a swept-frequency ultrasonic signal have been found to change frequency both in response to a change in composition and in response to a change in the flow velocity thereof. Additionally, the distance between successive resonance peaks does not change as a function of flow, but rather in response to a change in composition. Thus, a measurement of both parameters (resonance position and resonance spacing), once calibrated, permits the simultaneous determination of flow rate and composition using the apparatus and method of the present invention.

Abstract: An acoustical cell for analysis of materials by measuring parameters of acoustical velocity, attenuation and/or resonance. The cell comprises a main frame 5 and an electroacoustical transducer assembly. The main frame includes at least one interstice and has substantially parallel exterior surfaces mat engage, in use, with walls to define a sample cavity into which a specimen for analysis is placed in use. The electroacoustical transducer assembly is acoustically coupled to at least one of the walls and comprises at least one electroacoustical transducer. Analysing means for analysing me output of the electroacoustical transducer assembly is also provided. A corresponding method is also provided.

Abstract: An analytical apparatus, such as a quartz crystal microbalance, comprising a piezoelectric sensor and an oscillator circuit, coupled to the sensor, to oscillate at a frequency substantially determined by a resonant frequency of the sensor, and to provide an output signal at the oscillator frequency at an output, the oscillator circuit incorporates means to maintain a substantially constant drive signal to the piezoelectric sensor. Preferably the substantially constant drive signal is maintained by AGC means (33) within a feedback loop of the oscillator. Advantageously the gain control signal is used as an indication of the Q of the piezoelectric sensor. It is desirable that the drive signal to the sensor is substantially sinusoidal since this provides greater accuracy, sensitivity and stability for the apparatus. This can be achieved by ensuring that all the elements in the feedback loop providing signal gain and attenuation are configured to operate in a substantially linear mode.

Abstract: In the prevent invention a controllable acoustic source (14) in connection with the process fluid (10) emits a signal (18) into the fluid (10), consisting of a suspension of particles (12), being volumes of gas, liquid or solid phase. The controllable acoustic signal (18) is allowed to interact with the particles (12), and the acoustic (pressure) signals (22) resulting from such an interaction is measured preferably via a sensor (24). A spectrum is measured. The spectrum is used to predict properties, content and/or size of the particles (12) and/or used to control a process in which the process fluid (10) participates. The prediction is performed in the view of the control of the acoustic source (14). The used acoustic signal has preferably a frequency below 20 kHz.

Abstract: A process is provided for determining the degree of damage to keratinous fibers. The process includes providing a container containing a liquid preparation, introducing keratinous fibers into the container, and applying at least one impulse to the container to determine the degree of damage. The liquid preparation contains at least two immiscible continuous liquid phases, where the phases differ in densities at 20° C. by at least 0.04 g/ml.

Abstract: Systems and methods of monitoring thin film deposition are described. In one aspect, a thin film deposition sensor includes an acoustical resonator (e.g., a thin film bulk acoustical resonator) that has an exposed surface and is responsive to thin film material deposits on the exposed surface. A substrate clip may be configured to attach the thin film deposition sensor to a substrate. A transceiver circuit may be configured to enable the thin film deposition sensor to be interrogated wirelessly. A method of monitoring a thin film deposition on a substrate also is described.

Abstract: An analytical apparatus, such as a quartz crystal microbalance, comprising a piezoelectric sensor and an oscillator circuit, coupled to the sensor, to oscillate at a frequency substantially determined by a resonant frequency of the sensor, and to provide an output signal at the oscillator frequency at an output, the oscillator circuit incorporates means to maintain a substantially constant drive signal to the piezoelectric sensor. Preferably the substantially constant drive signal is maintained by AGC means (33) within a feedback loop of the oscillator. Advantageously the gain control signal is used as an indication of the Q of the piezoelectric sensor. It is desirable that the drive signal to the sensor is substantially sinusoidal since this provides greater accuracy, sensitivity and stability for the apparatus. This can be achieved by ensuring that all the elements in the feedback loop providing signal gain and attenuation are configured to operate in a substantially linear mode.

Abstract: An apparatus for noninvasively monitoring the flow and/or the composition of a flowing liquid using ultrasound is described. The position of the resonance peaks for a fluid excited by a swept-frequency ultrasonic signal have been found to change frequency both in response to a change in composition and in response to a change in the flow velocity thereof. Additionally, the distance between successive resonance peaks does not change as a function of flow, but rather in response to a change in composition. Thus, a measurement of both parameters (resonance position and resonance spacing), once calibrated, permits the simultaneous determination of flow rate and composition using the apparatus and method of the present invention.

Abstract: An acoustic wave sensor to detect an analyte, the sensor comprising a piezoelectric material including a wide bandgap semiconductor material grown using plasma source molecular beam epitaxy.

Abstract: The present invention discloses an apparatus for determining the density and the phase fraction of a fluid flowing in a conduit. The apparatus comprises a fiber optic density meter situated along the conduit that provides a signal indicative of the density of the fluid. The density meter includes two sound speed meters disposed at different sensing regions along the pipe. The sensing regions have a substantially different cross sectional area compliance. Each sound speed meter measures an acoustic pressure within the pipe at its corresponding axial location and provides a signal indicative of the effective fluid sound speed at its corresponding sensing region. Because each sensing region has a substantially different cross sectional area compliance, the density of the fluid is determined by the difference between the effective fluid sound speed signals. From the effective sound speed at either sensing region or from a separate acoustic sensor array, the infinite fluid sound speed may be determined.

Abstract: A sealant stream anomaly detecting assembly for detecting anomalies such as gas bubbles in a high-pressure sealant stream. The assembly includes an ultrasonic transducer supported on a manifold defining a sensing chamber of a fluid channel. The transducer converts electrical voltage pulses into ultrasonic acoustic pulses and propagates the acoustic pulses through the manifold and into the sensing chamber. The transducer also receives resulting echo pulses from a back wall of the sensing chamber and converts the echo pulses into electrical output impulses. A control module including drive electronics is connected to the transducer. The module detects diminished and lost echo pulses by comparing the output impulse strength values for a given fluid passing through the sensing chamber to a known output impulse strength value for that same type of fluid having no anomalies.

Abstract: The invention relates to a method and to apparatus for thermodynamic analysis of a mixture of fluids, in which the volume of a sample of a given quantity of said mixture is caused to vary step by step and in monotonic manner, and the pressure of the sample is read at each step, the sample being stirred at each step so as to hasten the mixture reaching thermodynamic equilibrium. According to the invention, the sample is stirred by applying ultrasound to said sample by means of transducer (20). The sample can be contained in a bag (19) of flexible material immersed together with the transducer in a control fluid inside a rigid container (10). The invention can be used to determine the bubble point of a mixture of hydrocarbons.

Abstract: A high resolution biosensing system for detecting and identifying a biochemical material to be tested by using proportional relationship between frequency variation of oscillation and mass of the biochemical material to be tested comprises a biosensor; an oscillatorfor generating oscillation based on the sensed result; a phase-lock loop circuit receiving the oscillation of the oscillator and generating pulse signals;an ultra-high frequency counter for counting the pulse signals; and a microprocessor for storing and displaying output from the ultra-high frequency counter and for controlling the oscillator. The phase-lock loop circuit generates the pulse signals of a frequency, which is n times the frequency of the oscillator and with a constant phase difference therebetween to trigger the ultra-high frequency counter. Accordingly, the resolution can be raised up to n times.

Abstract: A method of using ultrasonic reflectance to characterize physical properties of fluids, particularly food solutions. In general, the method comprises the steps of: (a) generating longitudinal ultrasonic waves, (b) coupling the transducer to the fluid being investigated, (c) detecting the reflected longitudinal waves, and (d) determining the physical property of interest by correlating certain characteristics of the reflected ultrasonic waves with the physical property being measured. A particular aspect of the invention is a self-calibrating ultrasonic device useful as a solids concentration sensor and/or a dissolution/precipitation sensor. Self calibration is accomplished via a twin delay line. The invention is particularly useful as an on-line sensor in the processing of food solutions such as milk, ketchup, syrup, chocolate and other confectionary.

Abstract: Systems and methods of monitoring thin film deposition are described. In one aspect, a thin film deposition sensor includes an acoustical resonator (e.g., a thin film bulk acoustical resonator) that has an exposed surface and is responsive to thin film material deposits on the exposed surface. A substrate clip may be configured to attach the thin film deposition sensor to a substrate. A transceiver circuit may be configured to enable the thin film deposition sensor to be interrogated wirelessly. A method of monitoring a thin film deposition on a substrate also is described.

Abstract: A method for measuring physical properties or characteristics of liquids uses an acoustic transfer system that utilizes Rayleigh waves. A wave guide with at least one test section formed from a solid surface made from non-piezo-electric material, contacts the liquid medium to be measured and/or a transfer system. A sender sends acoustic wave energy that includes at least one Rayleigh wave, and at least part of the acoustic wave energy leaving the sender passes at least once through a mode converter on its way to the receiver, whereby this part of its wave energy is converted at least partly from a Rayleigh wave (RW) into a volume sound wave (VW) or vice versa. The physical characteristics or physical properties of the liquid are then determined using changes of at least a parameter of the Rayleigh wave.

Abstract: A measurement device is provided that determines fluid properties from vibration frequencies of a sample cavity. In one embodiment, the measurement device includes a sample flow tube, vibration source and detector mounted on the tube, and a measurement module. The sample flow tube receives a flow of sample fluid for characterization. The measurement module employs the vibration sources to generate vibrations in the tube. The measurement module combines the signals from the vibration detector on the tube to determine properties of the sample fluid, such as density, viscosity, compressibility, water fraction, and bubble size. The measurement module may further detect certain flow patterns such as slug flow, for example. To measure the sample fluid density, the measurement module determines the resonant frequency of the sample flow tube. The density can then be calculated according to a formula that compensates for the temperature and pressure of the system.

Abstract: A method and apparatus for measuring properties of a liquid composition includes a mechanical resonator, such as a thickness shear mode resonator or a tuning fork resonator, connected to a measurement circuit. The measurement circuit provides a variable frequency input signal to the tuning fork, causing the mechanical resonator to oscillate. To test the properties of a liquid composition, the mechanical resonator is placed inside a sample well containing a small amount of the liquid. The input signal is then sent to the mechanical resonator and swept over a selected frequency range, preferably less than 1 MHz to prevent the liquid being tested from exhibiting gel-like characteristics and causing false readings. The mechanical resonator's response over the frequency range depends on various characteristics of the liquid being tested, such as the temperature, viscosity, and other physical properties.

Abstract: A process is provided for determining the degree of damage to keratinous fibers. The process includes providing a container containing a liquid preparation, introducing keratinous fibers into the container, and applying at least one impulse to the container to determine the degree of damage. The liquid preparation contains at least two immiscible continuous liquid phases, where the phases differ in densities at 20° C. by at least 0.04 g/ml.

Abstract: Systems and methods of monitoring thin film deposition are described. In one aspect, a thin film deposition sensor includes an acoustical resonator (e.g., a thin film bulk acoustical resonator) that has an exposed surface and is responsive to thin film material deposits on the exposed surface. A substrate clip may be configured to attach the thin film deposition sensor to a substrate. A transceiver circuit may be configured to enable the thin film deposition sensor to be interrogated wirelessly. A method of monitoring a thin film deposition on a substrate also is described.

Abstract: A transducer includes a resonant structure having a first spring-mass system extending to a connection mass or nexus to which is connected a second spring-mass system, which includes a sensing element. The two spring-mass systems vibrate in antiphase. The nexus is connected to a mechanical datum provided by a mounting by means of a semi-rigid connection member which is preferably stiffer than the first member and which can control the relative motions of the first and second spring-mass systems. The sensing element contains a re-entrant resonator constituted by a spring-mass system, which can be used to adjust the characteristics of the transducer.

Abstract: A method and corresponding system for measuring the speed of sound in a fluid contained within an elongated body, the sound traversing the elongated body substantially along a direction aligned with the longest axis of the elongated body, the sound causing a momentary change in pressure in a portion of the fluid as the sound traverses the portion of the fluid, the method including the steps of: providing at predetermined locations an array of at least two sensors distributed along the elongated body, each sensor for discerning and signaling spatio-temporally sampled data including information indicating the pressure of the fluid at the position of the sensor; acquiring the spatio-temporally sampled data from each sensor at each of a number of instants of time; constructing a plot derivable from a plot, using a technique selected from the group consisting of spectral-based algorithms, such as the Capon method or the MUSIC method, in which a spectrum-like function of the speed of sound is formed, and parametric