Abstract: A method for manufacturing a flexural plate wave sensor includes the steps of depositing an etch-stop layer over a substrate, depositing a membrane layer over the etch stop layer, depositing a piezoelectric layer over the membrane layer, forming a transducer on the piezoelectric layer, etching a cavity through the substrate, the cavity having substantially parallel interior walls, and removing the portion of the etch stop layer between the cavity and the membrane layer to expose a portion of the membrane layer.

Abstract: An apparatus for measuring the mass of a substance includes a sensor having a membrane layer, the membrane for receiving the substance thereon, an oscillator device for driving the membrane at a reference resonant frequency, a frequency detection device for determining a change in the reference resonant frequency caused by the presence of the substance on the membrane, and a mass determining device for determining the mass of the substance, the change in the reference resonant frequency being indicative of the mass of the substance.

Abstract: A measuring apparatus for detecting a change in frequency of a piezoelectric vibrating reed is realized with a simple circuit. The circuit of the measuring apparatus includes a phase lock loop circuit 20 which includes a phase comparator 22, a loop filter 24, and a voltage-controlled oscillator 26. An oscillator circuit 10 of a piezoelectric vibrating reed 12 is connected to the phase comparator 22. An output terminal 30 is provided downstream of the loop filter 24. In a method for measuring mass from a change in oscillation frequency of the piezoelectric vibrating reed 12, an input signal from the piezoelectric vibrating reed 12 is input to the phase comparator 22 of the phase lock loop circuit 20 and the oscillation frequency of the piezoelectric vibrating reed 12 is obtained based on the output from the loop filter 24 of the phase lock loop circuit 20.

Abstract: The mass measurement system includes a linear acceleration motion unit that is a linear motion driving source, a first load cell fastened to the linear acceleration motion unit to measure an inertial force of a sample caused by linearly accelerated motion of the 10 linear acceleration motion unit, a second load cell fastened to the linear acceleration motion unit while being spaced apart from the first load cell by a predetermined distance, the second load cell measuring an inertial force of a standard sample having a known standard mass caused by the linearly accelerated motion of the linear acceleration motion unit, and a main control unit for calculating and outputting mass of the sample through an arithmetic operation based on the inertial forces, measured by the first and second load cells, and the standard mass, and controlling an entire operation of the system.

Abstract: A sensor for detecting mechanical perturbations represented by a change in an electrical signal includes a structure such as a cantilever, membrane, etc. and a field effect transistor such as a MOSFET embedded in the structure. The drain current of the embedded transistor changes with mechanical perturbations in the structure caused, for example, by a bio-chemical interaction being sensed. A scanning probe microscope utilizes the embedded MOSFET with a BiMOS actuator.

Abstract: A scale is provided, the scale including a cavity having a resonant frequency which is alterable with variations in mass of a load applied to the cavity. The scale also typically includes a comparator operatively coupled with the cavity to detect actual resonant frequency under the load, to compare such actual resonant frequency with a reference resonant frequency, and to produce a difference signal indicative of mass of the load.

Abstract: A weighing apparatus includes a SAW oscillator and a “push oscillator” to force the SAW oscillator into a desired mode of operation. A SAW temperature oscillator and a thermistor are also provided. The frequency of the “push oscillator” is made immune to temperature changes by generating it via a mixer mixing the SAW temperature oscillator with an adjustable fixed frequency oscillator. Long term stability of the SAW temperature oscillator is achieved by periodic calibration with the thermistor.

Abstract: A flexural plate wave sensor array includes a substrate, and a plurality of flexural plate wave sensors, each sensor including a cavity formed in the substrate, a thin film membrane layer spanning the cavity, a piezoelectric layer disposed on the thin film membrane layer, a transducer disposed on the piezoelectric layer and an absorptive coating disposed on said thin film membrane layer within the cavity. The cavity of each of the sensors includes interior walls which are substantially parallel to each other and to the interior walls of adjacent sensors.

Abstract: A sensor readout circuit which provides a frequency signal output including a phase detector circuit responsive to an output signal from a sensor and an input signal to the sensor and configured to detect the phase difference between the input signal and the output signal, and a drive circuit responsive to the phase detector circuit and configured to maintain a fixed phase difference between the input signal and the output signal.

Abstract: A system and method for providing resonant movement about a first axis. A functional surface supported by a first pair of torsional hinges is driven into resonant oscillations about the first axis by inertially coupling energy through the first pair of torsional hinges. The resonant movement may be moved orthogonally on the target area by a gimbals portion of the functional surface pivoting about a second axis according to one embodiment. The resonant oscillation of the functional surface is monitored to detect changes in frequency due to mass changes of the functional surface.

Abstract: The invention provides an apparatus for measuring the mass and calculating the weight of individual objects to be held thereby, comprising forceps having a proximal portion and a distal portion, the proximal portion being adapted to grasp and hold a selected object, means associated with the forceps for initiating vibration of the same while the object is held thereby and means for measuring the oscillating frequency of the forceps while the object is held thereby, and for utilizing the measured higher oscillating frequency of the empty forceps to compute the mass and the weight of the selected object.

Abstract: A substance mass measuring system is applied to a microgravitational rotating apparatus vibration control system to easily measure the mass of an object placed in an experimental box. Recess portions (10a, 10b) are provided in a casing (10). Both ends of a rotary shaft (30) are supported by bearings (11, 12) in the recess portions (10a, 10b). A lower end of the rotary shaft (30) is connected to a motor (13). Four arms (24 to 27) arranged horizontally in the direction of X and Y axes, are at their one ends fixed to the rotary shaft (30) and at the other ends fitted with experimental boxes (20 to 23). Experimental objects are placed in the boxes (20 to 23) and rotated for experiments in space. Vibration of the rotary shaft (30) and the boxes (20 to 23) is absorbed by the bearings (11, 12). Side plates (1a to 1d), acceleration sensors (2a to 2d) and distance sensors (3a to 3d) are arranged in the boxes (20 to 23).

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: A device for measuring thickness and/or rate of thickness increase of a film comprises at least one piezoelectric element, and first and second electrodes in contact with the piezoelectric element. A method of measuring thickness and/or rate of thickness increase of a film comprises applying a voltage across a piezoelectric element from a first electrode to a second electrode, thereby causing the piezoelectric element to vibrate, and measuring the rate of vibration of the piezoelectric element. Heat may be applied to the piezoelectric element. The piezoelectric element may be formed of quartz crystal, e.g., IT-cut.

Abstract: A resonant sensor for determining structural property changes, in particular for detecting the presence of chemical or biological species, comprises a structure (2) mounted to be capable of resonating and having a cyclically symmetrical configuration with two independent degenerative modes of vibration of a common natural frequency (f), and means (24,26,28,30,32,34,36,38) for exciting the structure (2) to resonate according to the two degenerative modes, regions (8,12,16,20) of the structure (2) being modified such that, on changes in the structural properties of the modified regions (8,12,16,20), for example by the addition or subtraction of mass, the natural frequencies (f1, f2) of the two modes of vibration become different, the difference in frequencies (?f) being proportional to the change in structural properties.

Abstract: A piezoelectric crystal element and a sensor utilizing the same are presented for use in a sensor device for identifying at least one foreign material from environment. The crystal element comprises at least one crystal resonator in the form of an inverted mesa structure, which has a membrane-like region and has a certain resonance frequency value. A surface region of the crystal resonator is modified by reactive molecules of a kind capable of interacting with the foreign material to yield a reaction product that effects a change in the resonance frequency of the crystal resonator from said certain resonance frequency value. This change is indicative of the identity and quantity of the foreign material.

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: 22A temperature and/or pressure compensated microbalance is disclosed. Temperature compensation is achieved by applying heat to at least a part of the microbalance, measuring a temperature-dependent variable, and controlling the amount of heat applied to the microbalance to keep the temperature-dependent variable substantially constant. In one embodiment, the heat is applied to the microbalance by passing electrical current through a resistive element provided on or embedded in the oscillating element of the microbalance. Pressure compensation is achieved by taking into account the variation in the mass or density of fluid passing through the microbalance. Various materials and methods of construction are also disclosed, including micro-machining and electroforming.

Abstract: An apparatus and method of measuring the mass of a test specimen located in a microgravity environment. The test specimen is attached to the free end of a cantilevered spring for joint vibration. The natural frequency of vibration of the spring and specimen are measured. The spring constant is calculated and compared with known masses having the same frequency and spring constant. When a match is found, the mass of the test specimen is known.

Abstract: The invention relates to the application of the techniques of nanoelectromechanical systems (NEMS) to ultrasensitive mass detection. A pulsed flux of atoms is adsorbed onto the surface of a 32.8 MHz nanomechanical resonator within an ultrahigh vacuum environment. The mass-induced frequency shifts from these adsorbates are then used to demonstrate a mass sensitivity of ˜1.46×106 Daltons (Da). For resonators operating up to frequencies of 72 MHz, inverse mass responsivities as small as ˜8×10−20 grams/Hz (5×104 Da/Hz) are obtained. Our results offer a new approach to ultrahigh resolution mass spectrometry of individual, electrically-neutral macromolecules with clear prospects for single Dalton sensitivity.

Abstract: A controller for a quartz crystal microbalance (QCM) sensor system and method for detecting mass deposition on a QCM sensor. The controller controls a QCM using temperature-, voltage- and current-regulating circuits, a microcontroller, an oscillator, heating and cooling devices and circuits, high voltage grids, digital-to-analog and analog-to-digital converters, data telemetry and uplink circuits, and a remote user. The remote user may be a person, computer, network or data logger. The remote user allows the controller to be reconfigurable during operation. The controller samples and reports data faster and is more reliable over extended periods of operation. Further, the controller is assembled using innovative techniques making it smaller and thus more transportable, easier to incorporate into existing facilities and less expensive to construct and operate. The apparatus may also be assembled in a modular fashion that allows for customization.

Abstract: A seismic weigh-in-motion system (12) which utilizes a seismic sensor (32) mounted, off-pavement of the highway prior to the point at which the truck (10) enters the deceleration lane at the truck weighing station. The sensor (32) senses seismic vibrations which are transferred into the ground by the moving truck (10). Signals indicative of these vibrations are transmitted through a fiber optic cable (44) connected to a main processor (42) mounted in the weigh-in station. These vibration signals along with signals proportional to the speed of the truck (determined by speed detecting devices/processes (34, 36)) as the truck moves down the highway is processed in the processor (42) to provide an output which is indicative of the weight of the truck. Additional components such as soil temperature (28) and soil moisture content (30) measuring devices provide additional inputs to the processor (42) to increase accuracy of the system.

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: A quartz crystal sensor cell in which the sensor is secured to the base of a well defining a test sample space by a layer of adhesive between the respective peripheral surfaces. Also a quartz crystal sensor cell is provided in which the quartz sensor crystal is inclined relative to the opposite surface of the test sample space. These constructions respectively improve distinctness of the “Q” peak and problems from reflected waves in the space.

Abstract: A system and method for providing resonant movement about a first axis. A functional surface supported by a first pair of torsional hinges is driven into resonant oscillations about the first axis by inertially coupling energy through the first pair of torsional hinges. The resonant movement may be moved orthogonally on the target area by a gimbals portion of the functional surface pivoting about a second axis according to one embodiment. The resonant oscillation of the functional surface is monitored to detect changes in frequency due to mass changes of the functional surface.

Abstract: A method for measuring the mass of nano-substances including the steps of gripping a nano-substance with a nanotweezer gripping portion made of a plurality of nanotubes, resonating the nanotweezer gripping portion in this gripping state, measuring a resulting first characteristic frequency, and obtaining the mass of the gripped nano-substance by comparing the first and second characteristic frequencies, where the second characteristic frequency is the characteristic frequency of the nanotweezer gripping portion with no nano-substance gripped thereby. The gripping portion is caused to resonate electrically by applying an AC voltage between the nanotweezer gripping portion and an electrode disposed near the nanotweezer gripping portion. The gripping portion is caused also to resonate mechanically by way of expanding and contracting a piezo-electric element disposed on a main body that supports the nanotweezer gripping portion.

Abstract: The invention is directed to a method for determining the weight of a probe of a coordinate measuring machine wherein the probe is connected to a probe head (1) of the machine. The machine includes a control unit and the weight of the probe (3) is preferably statically determined without active control of the movement of the probe. Signals from the probe (3) and/or the probe head (1) are supplied to the control unit (51).

Abstract: The invention relates to methods, kits and systems for determining an analyte in a liquid sample as well as the use thereof for concentration analysis and screening purposes. In one method, a specific binding partner to the analyte is permitted to compete with a conjugate containing the analyte or an analyte analogue for the binding to free analyte. The conjugate also contains a component that specifically binds to a solid support so that reacted and unreacted conjugate are bound thereto when the reaction solution is contacted with the solid support. The amount of analyte is then determined by measuring by a label-free mass-detection technique, such as surface plasmon resonance, the amount of binding partner immobilized on the solid support via the reacted conjugate. This is made possible by the binding partner having a considerably greater mass than the conjugate. Variants of this method are also disclosed.

Abstract: An apparatus and method of measuring the mass of a test specimen located in a microgravity environment. The test specimen is attached to the free end of a cantilevered spring for joint vibration. The natural frequency of vibration of the spring and specimen are measured. The spring constant is calculated and compared with known masses having the same frequency and spring constant. When a match is found, the mass of the test specimen is known.

Abstract: An apparatus and method for sensing chemical and/or biological analytes includes a deflectable arm of a microcantilever formed over and contacting a sensing element. A gaseous or liquid medium which may include the analyte being detected, is introduced to the sensing element. The sensing element undergoes volumetric expansion or contraction in the presence of the analyte sought to be detected, typically by adsorbing the analyte. The volumetric change of the sensing element causes the deflectable arm to deflect. The deflectable arm includes at least one measurable physical property which changes when the arm deflects. Detecting means are provided to measure the change in the physical property to determine the presence and amount of analyte present. An array of microcantilevers in which each microcantilever is dedicated to detecting a particular analyte which may be included in the medium, is also provided.

Abstract: The invention relates to the application of the techniques of nanoelectromechanical systems (NEMS) to ultrasensitive mass detection. A pulsed flux of atoms is adsorbed onto the surface of a 32.8 MHz nanomechanical resonator within an ultrahigh vacuum environment. The mass-induced frequency shifts from these adsorbates are then used to demonstrate a mass sensitivity of ˜1.46×106 Daltons (Da). For resonators operating up to frequencies of 72 MHz, inverse mass responsivities as small as ˜8×10−20 grams/Hz (5×104 Da/Hz) are obtained. Our results offer a new approach to ultrahigh resolution mass spectrometry of individual, electrically-neutral macromolecules with clear prospects for single Dalton sensitivity.

Abstract: A controller for a quartz crystal microbalance (QCM) sensor system and method for detecting mass deposition on a QCM sensor. The controller controls a QCM using temperature-, voltage- and current-regulating circuits, a microcontroller, an oscillator, heating and cooling devices and circuits, high voltage grids, digital-to-analog and analog-to-digital converters, data telemetry and uplink circuits, and a remote user. The remote user may be a person, computer, network or data logger. The remote user allows the controller to be reconfigurable during operation. The controller samples and reports data faster and is more reliable over extended periods of operation. Further, the controller is assembled using innovative techniques making it smaller and thus more transportable, easier to incorporate into existing facilities and less expensive to construct and operate. The apparatus may also be assembled in a modular fashion that allows for customization.

Abstract: An apparatus and method for weighing particulates in a gas stream has a generally cylindrical tube manufactured from a magnetostrictive material. One end of the tube is anchored to a mounting block, while the other end includes a filter. The gas stream passes through a filter, where particulates are collected. Several alternative filters provide various alternative benefits for varying applications to different sensing applications. Between the two ends of the magnetostrictive tube are electromagnetic drive and pick-up coils which are magnetically coupled to the tube. The drive coils are driven by an electrical current from an electronic control circuit to generate alternating magnetic fields. These alternating fields in turn stimulate ultrasonic oscillations in the magnetostrictive tube, causing the tube to extend and retract along the length. Oscillation is in the longitudinal direction only, resulting in only one mode of operation.

Abstract: 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.

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 weighing apparatus includes a SAW oscillator and a “push oscillator” to force the SAW oscillator into a desired mode of operation. A SAW temperature oscillator and a thermistor are also provided. The frequency of the “push oscillator” is made immune to temperature changes by generating it via a mixer mixing the SAW temperature oscillator with an adjustable fixed frequency oscillator. Long term stability of the SAW temperature oscillator is achieved by periodic calibration with the thermistor.

Abstract: 22A temperature and/or pressure compensated microbalance is disclosed. Temperature compensation is achieved by applying heat to at least a part of the microbalance, measuring a temperature-dependent variable, and controlling the amount of heat applied to the microbalance to keep the temperature-dependent variable substantially constant. In one embodiment, the heat is applied to the microbalance by passing electrical current through a resistive element provided on or embedded in the oscillating element of the microbalance. Pressure compensation is achieved by taking into account the variation in the mass or density of fluid passing through the microbalance. Various materials and methods of construction are also disclosed, including micro-machining and electroforming.

Abstract: A method and apparatus for measuring the mass of individual objects, particularly small diamonds, within a predetermined range of sizes, by conveying the objects towards an oscillatable probe having a predetermined mass and a vacuum port of smaller dimensions than those of the objects; applying vacuum to the vacuum port to attract and hold thereto one of the individual objects to thereby add its mass to the mass of the oscillatable probe; measuring the oscillating frequency of the oscillatable probe while the individual object attracted thereto is held by the vacuum applied to the vacuum port, and utilizing the measured oscillating frequency of the probe and the object attracted thereto to compute the mass of the object, before releasing the vacuum to release the object.

Abstract: To provide a compact vibrating transport apparatus in which the amount of an article M to be transported can be controlled highly accurately, the vibrating transport apparatus is designed to transport the article M loaded on a trough 4 by vibrating the trough 4 in a predetermined vibrating direction. The apparatus includes strain gauges 14a to 14d mounted on a portion of the transport apparatus where elastic strains are developed upon placement of the article M on the trough 4, and a weight detecting circuit 15 for detecting the weight W of the article M placed on the trough 4 on the basis of the amount of the strains detected by the strain gauges 14a to 14d.

Abstract: A mass sensor includes a diaphragm, a sensing plate having a piezoelectric element arranged on at least a part of at least one surface joining respective sides, a connecting plate sandwiched by the diaphragm and the sensing plate, wherein the diaphragm, the sensing plate, the piezoelectric element, and the connecting plate form a resonating portion. The connecting plate is bridged across the side surfaces of a concave portion formed in a sensor substrate, and the sensing plate is joined to at least the bottom portion of the concave portion. Change in the mass of the diaphragm is measured by measuring change in the resonant frequencies of the resonating portion accompanying the change in the mass of the diaphragm. The mass sensor enables the easy and accurate measurement of a minute mass of a nanogram order including microorganisms such as bacteria and viruses, or chemical substances, or the thickness of vapor-deposited films.

Abstract: A system and method for preconcentrating, identifying, and quantifying chemical and biological substances is disclosed. An input valve directs a first volume of a sample gas to a surface acoustic wave (SAW) device. The SAW device preconcentrates and detects a mass of a substance within the sample gas. An output valve receives a second volume of the sample gas containing the preconcentrated substance from the SAW device and directs the second volume to a gas chromatograph (GC). The GC identifies the preconcentrated substance within the sample gas. A shunt valve exhausts a volume of the sample gas equal to the first volume minus the second volume away from the SAW device and the GC.

Abstract: A mass determination device includes a combination of an elastic element connected with a mass holder. The combination has a normalized temperature coefficient of frequency substantially equal to zero over a temperature range of intended use for the mass determination device, whereby mass determination accuracy of the device during temperature change in the range is enhanced. The elastic element has a first normalized temperature coefficient of frequency over the temperature range. A second normalized temperature coefficient of frequency over the temperature range attributable to the mass holder is determined. The first normalized temperature coefficient and the second normalized temperature coefficient are substantially counterbalanced over the temperature range, for example, through material selection and/or heat treatment of the elastic element and/or material or geometry variation of the mass holder.

Abstract: The present invention provides a method and device for measuring granule impact strength by vibrating a small container of granules at a well-controlled amplitude in order to inflict reproducible damage to the granules. Damage to the granules is measured as a function of time and amplitude. The measurements characterize granule attrition and fragmentation.

Abstract: A method for determining a total weight supported by the suspension system of a vehicle in motion starts by obtaining information sufficient to calculate a representative value of a spring constant for the suspension system of the vehicle. Measures are then obtained of the vertical acceleration of the center of mass of the vehicle over a period of time, and these are analyzed to identify a frequency of vertical oscillation of the vehicle. This frequency, together with the spring information, is used to determine an estimate of the total weight supported by the suspension system of the vehicle. Preferably, the measure of vertical acceleration is obtained by processing outputs of at least three motion sensors attached to the vehicle. In one embodiment, the motion sensors include one linear sensor deployed to measure vertical motion information for a part of the vehicle and two angular sensors deployed to measure pitch and roll information for the vehicle.

Abstract: A non-destructive process for estimating the ageing of an article made of a composite material is described comprising a preliminary phase in which at least one chart is prepared characterizing the change in the attenuation of ultrasonic waves in the composite material as a function of weight loss thereof, and a checking phase in which the attenuation of ultrasonic waves in the article made of the composite material is measured and the weight loss of the article is determined using the chart prepared in the preliminary phase, the weight loss being representative of the ageing of the article.

Abstract: A method for measuring the masses of objects in any gravity environment, including microgravity or zero gravity. An object is placed on or attached to a platform that is movable back and forth along a single axis of motion. An actuator is used to oscillate the platform and is controlled to provide a variable spring force. Instantaneous displacement values are obtained and used to calculate the period of oscillation. Values representing the period, the tare mass of the platform, and the spring constant are then used to calculate the mass of the object. The method may use active damping, and may be varied so that the oscillations are angular rather than linear.

Abstract: A method for measuring the masses of objects in any gravity environment, including microgravity or zero gravity. An object is placed on or attached to a platform or holder having a motor for rotating the platform. The object is rotated at an angular velocity and its centrifugal force is measured. Values representing the centrifugal force, the angular velocity, the tare mass of the platform, as well as a radial distance, are used to calculate the mass of the object. Three different variations of the method use different radial distance values.

Abstract: A quartz crystal resonator is excited in two different modes at the same time such that the mass change and the temperature change can be measured independently. In using such a quartz crystal the change in mass can be calculated accurately and in real time, independent of temperature effects.

Abstract: A chemical sensor for measuring a change in the sensor mass relating to the interaction of a surface of the sensor with a solution comprises a crystal detector oscillator capable of providing a measurement signal based upon the resonant frequency of the crystal detector oscillator. The crystal detector oscillator has a first crystal side for directly contacting the solution, and a second crystal side isolated from contacting the solution. A first electrode is integral to the first crystal side, with the first electrode having an inner and outer perimeter defining an outer portion of the first crystal side which is exterior to the outer perimeter of the first electrode and an inner portion of the first crystal side which is interior to the inner perimeter of the first electrode. A second electrode is integral to the second crystal side.

Abstract: The invention relates to a method and apparatus for dynamic determination of the thickness and/or basis weight of moving material under test. The material under test is exposed to a focused ultrasound filed with high sound intensity, whereby the sound fraction coming from the material under test is detected directly in the near filed, i.e. at a distance smaller than or equal to the acoustic wavelength used, and evaluated for determining the thickness and/or basis weight. The near-field measurement preferably takes place with continuous sound and in transmission.