1160results about "Resonant frequency" patented technology

A method for the detection of analytes using resonant mass sensors or sensor arrays comprises frequency encoding each sensor element, acquiring a time-domain resonance signal from the sensor or sensor array as it is exposed to analyte, detecting change in the frequency or resonant properties of each sensor element using a Fourier transform or other spectral analysis method, and classifying, identifying, and/or quantifying analyte using an appropriate data analysis procedure. Frequency encoded sensors or sensor arrays comprise sensor elements with frequency domain resonance signals that can be uniquely identified under a defined range of operating conditions. Frequency encoding can be realized either by fabricating individual sensor elements with unique resonant frequencies or by tuning or modifying identical resonant devices to unique frequencies by adding or removing mass from individual sensor elements. The array of sensor elements comprises multiple resonant structures that may have identical or unique sensing layers. The sensing layers influence the sensor elements' response to analyte. Time-domain signal is acquired, typically in a single data acquisition channel, and typically using either (1) a pulsed excitation followed by acquisition of the free oscillatory decay of the entire array or (2) a rapid scan acquisition of signal from the entire array in a direct or heterodyne configuration. Spectrum analysis of the time domain data is typically accomplished with Fourier transform analysis. The methods and sensor arrays of the invention enable rapid and sensitive analyte detection, classification and/or identification of complex mixtures and unknown compounds, and quantification of known analytes, using sensor element design and signal detection hardware that are robust, simple and low cost.

Methods and apparatus for screening diverse arrays of materials are provided. In one aspect, systems and methods are provided for imaging a library of materials using ultrasonic imaging techniques. The system includes one or more devices for exciting an element of the library such that acoustic waves are propagated through, and from, the element. The acoustic waves propagated from the element are detected and processed to yield a visual image of the library element. The acoustic wave data can also be processed to obtain information about the elastic properties of the library element. In another aspect, systems and methods are provided for generating acoustic waves in a tank filled with a coupling liquid. The library of materials is then placed in the tank and the surface of the coupling liquid is scanned with a laser beam. The structure of the liquid surface disturbed by the acoustic wave is recorded, the recorded disturbance being representative of the physical structure of the library. In another aspect of the invention, a mechanical resonator is used to evaluate various properties (e.g., molecular weight, viscosity, specific weight, elasticity, dielectric constant, conductivity, etc.) of the individual liquid elements of a library of materials. The resonator is designed to ineffectively excite acoustic waves. The frequency response of the resonator is measured for the liquid element under test, preferably as a function of time. By calibrating the resonator to a set of standard liquids with known properties, the properties of the unknown liquid can be determined. An array of library elements can be characterized by a single scanning transducer or by using an array of transducers corresponding to the array of library elements. Alternatively, multiple resonators of differing design may be used to evaluate each element of a library of elements, thus providing improved dynamic range and sensitivity.

A method for determining the quality of an examined weld joint comprising the steps of providing acoustical data from the examined weld joint, and performing a neural network operation on the acoustical data determine the quality of the examined weld joint produced by a friction weld process. The neural network may be trained by the steps of providing acoustical data and observable data from at least one test weld joint, and training the neural network based on the acoustical data and observable data to form a trained neural network so that the trained neural network is capable of determining the quality of a examined weld joint based on acoustical data from the examined weld joint. In addition, an apparatus having a housing, acoustical sensors mounted therein, and means for mounting the housing on a friction weld device so that the acoustical sensors do not contact the weld joint. The apparatus may sample the acoustical data necessary for the neural network to determine the quality of a weld joint.

Disclosed is a piezoelectric resonator, a process for the fabrication thereof and its use as a sensor element, which implemented in a through-flow cell, is integratable in a measurement system for the determination of the concentration of a substance contained in a liquid and/or for the determination of the physical properties of the liquid. The piezoelectric resonator is designed plane and is provided on its surface with electric contact areas for an electrode and a counter electrode, which is connectable to a signal source as well as to a measurement device. For measuring, the piezoelectric resonator is brought into contact with the to-be-examined liquid on one side, with the resonator responding to the accumulation of the mass of the to-be-detected substance or to a change in the physical properties of the liquid by changing its resonance frequency and/or oscillation amplitude.The present invention is distinguished by the fact that the piezoelectric resonator is provided with contact electrode areas which is contactable from one single side of the resonator. The resonator is the heart piece of a sensor element, which is integrated in a through-flow cell. The through-flow cell us insertable module-like in a measurement arrangement for determining the concentration of a substance contained in a liquid and/or determining the physical properties of the liquid.

A mass sensor including: a connecting plate having one or more slit(s) and/or opening portion(s) formed therein and/or having a thin-walled portion and a thick-walled portion formed therein; a diaphragm joined with the connecting plate at respective side surfaces; a piezoelectric element; a sensing plate with the piezoelectric element being provided at least at one part on at least one surface of the sensing plate, which has its side surface joined with a side surface of the connecting plate in the direction perpendicular to the joining direction of the diaphragm and the connecting plate; and a sensor substrate with which at least a part of side surfaces of the connecting plate as well as the sensing plate are joined, and the diaphragm, the connecting plate, the sensing plate, and the piezoelectric element form a resonating portion. The mass sensor can conveniently be used for determining the mass of a substance to be sensed by measuring changes in resonant frequencies caused by changes in the mass of the diaphragm on which a catching substance for catching a substance to be sensed by reacting only with the object of sensing is applied.

An array of piezoelectric resonators used in a sensor device in order to identify chemical and biological agents. The resonators can operate as bulk acoustic wave (BAW), surface acoustic wave (SAW), or Love mode devices. The sensor device integrates gravimetric, calorimetric, thermal gravimetric, voltage gravimetric and optical detection methods into one sensor system, improving the accuracy of identifying hazardous agents. For gravimetric detection, dual-mode resonators provide simultaneous calorimetric and gravimetric data, one type from each mode. Resonators with heaters on the surfaces will provide thermal gravimetric data. An optical detector can be used to analyze the optical signal from the surface of a coated resonator. Additionally, voltage gravimetric measurements can be made with an electric field set up between the resonator and an external electrode. Thermal voltage gravimetric measurements can be made by adding an integrated heater on the resonator with an external electrode. An alarm can be activated upon the identification of a hazardous agent. The sensor device can utilize other valuable information, including traceable time, GPS location, and variables related to temperature, humidity, air speed, and air direction.

A method of analyzing vibrations of a rolling element bearing installed in a rotating machine includes accessing vibration data corresponding to the bearing to be analyzed, determining a degraded condition factor BD for the bearing, selecting an expected designer-determined mean-time-to-failure MTTF of the bearing operating under a design load in the operating environment of the rotating machine, selecting a forecast time period, calculating a reduced mean-time-to-failure RMTTF of the bearing using the expected designer-determined mean-time-to-failure MTTF and the degraded condition factor BD, calculating a probability of failure of the bearing in the forecast time period using the reduced mean time to failure RMTTF, accessing cost data corresponding to a cost of failure of the bearing in the rotating machine, calculating a financial risk from the calculated probability of failure in the forecast time period and the cost data, and displaying the financial risk for the selected time period.

In industrial sensing applications at least one parameter of at least one fluid in a pipe 12 is measured using a spatial array of acoustic pressure sensors 14,16,18 placed at predetermined axial locations x1, x2, x3 along the pipe 12. The pressure sensors 14,16,18 provide acoustic pressure signals P₁(t), P₂(t), P₃(t) on lines 20,22,24 which are provided to signal processing logic 60 which determines the speed of sound a_mix of the fluid (or mixture) in the pipe 12 using acoustic spatial array signal processing techniques with the direction of propagation of the acoustic signals along the longitudinal axis of the pipe 12. Numerous spatial array-processing techniques may be employed to determine the speed of sound a_mix. The speed of sound a_mix is provided to logic 48, which calculates the percent composition of the mixture, e.g., water fraction, or any other parameter of the mixture, or fluid, which is related to the sound speed a_mix. The logic 60 may also determine the Mach number Mx of the fluid. The acoustic pressure signals P₁(t), P₂(t), P₃(t) measured are lower frequency (and longer wavelength) signals than those used for ultrasonic flow meters, and thus is more tolerant to inhomogeneities in the flow. No external source is required and thus may operate using passive listening. The invention will work with arbitrary sensor spacing and with as few as two sensors if certain information is known about the acoustic properties of the system. The sensor may also be combined with an instrument, an opto-electronic converter and a controller in an industrial process control system.

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.

An apparatus and method for determining the kinematic characteristics of a golf club head are disclosed. The apparatus includes at least one piezoelectric component selectively positioned within or upon a club head. The piezoelectric component is preferably positioned to the rear of the center of gravity, and near the midpoint of the face of the club head. During a golf club swing, the piezoelectric component determines the acceleration and deceleration of the golf club head. When the club head impacts an object such as a golf ball, the piezoelectric component is also operable to determine the velocity of the club head. It may also be desirable for the piezoelectric component to determine the magnitude of vibration during impact. In this manner, the piezoelectric component may function determine the efficiency of a golf club swing.

Acoustic sensing utilizing a cantilever structure coupled about at least one side of said cantilever to a base substrate, wherein said cantilever includes a piezoelectric section and has at least one acoustic wave device on a portion of the cantilever, wherein a flexure of the cantilever produces force-frequency effects measurable by the acoustic wave device. According to one embodiment, the cantilever sensor uses the flexure-frequency effect as measured by an acoustic wave device to sense a target matter. According to one embodiment, a sensing material is disposed on at least a portion of at least one surface of the cantilever.