Abstract: To provide a sensing device having a high processing power and capable of high-accuracy measurement. It is determined whether or not an oscillation frequency is stabilized while a buffer solution is supplied to a quartz-crystal resonator 4. from a syringe pump 10. When it is determined that the frequency is stabilized, a second valve 14. is switched to a sample solution supply mode to supply a sample solution in an injection loop 14a. to the quartz-crystal resonator 4. An instant at which the sample solution reaches the quartz-crystal resonator 4. and an instant at which the sample solution finishes passing through the quartz-crystal resonator 4. are automatically found based on a supply flow rate of the buffer solution, a volume of the injection loop 14a, a volume of a supply channel supplying the sample solution to the quartz-crystal resonator 4, and an instant at which the second valve 14. is switched to the sample solution supply mode.

Abstract: To provide a sensing device capable of easily sensing a substance to be sensed with high accuracy. When sensing, by supplying a sample solution to an absorption layer 46 while oscillating a quartz-crystal resonator 4 to make the absorption layer absorb a substance to be sensed in the sample solution, the substance to be sensed based on an amount of variation in an oscillation frequency of the quartz-crystal resonator 4 after an absorption time elapses, the quartz-crystal resonator 4 is oscillated, before supplying the sample solution to the absorption layer 46, to measure the oscillation frequency of the quartz-crystal resonator 4 at a predetermined measurement interval, for instance, at every one second, and the oscillation frequency of the quartz-crystal resonator 4 is stabilized for the same period of time as a measuring time 19 until the measurement result becomes equal to or less than a frequency tolerance value 19b previously set based on a measurement sensitivity of the substance to be sensed.

Abstract: To provide a sensing device and a sensing method that, by a simple method of liquid supply to first and second excitation electrodes, makes it possible to make a first oscillation area adsorb an adsorption substance that adsorbs a substance to be sensed in a sample solution and a blocking substance that prevents the adsorption of a substance and to make the electrode in a second oscillation area adsorb the blocking substance. By the supply of a solution containing the adsorption substance to a first liquid storage space 53A surrounding a first excitation electrode 42A, a front surface of the excitation electrode 42A is made to adsorb the adsorption substance, and next, by the supply of a solution containing the blocking substance to the first liquid storage space 53A, an area, of the excitation electrode 42A, on which the adsorption substance is not adsorbed, is made to adsorb the blocking substance.

Abstract: One or more of the embodiments of the present invention provide for a method of non-contact particle manipulation and control of particle spacing along an axis which includes axial and radial acoustic standing wave fields. Particles are suspended in an aqueous solution, and this solution then flows into the cylindrical flow channel. While the solution flows through the flow channel, the outer structure of the flow channel is vibrated at a resonant frequency, causing a radial acoustic standing wave field to form inside the flow channel in the solution. These radial acoustic standing waves focus the particles suspended in the solution to the center axis of the cylindrical flow channel. At the same time, a transducer is used to create an axial acoustic standing wave field in the flow channel parallel to the axis of the flow channel.

Abstract: A method for analyzing liquid samples may comprise applying a liquid to a cMUT device having a plurality of sensors, drying the plurality of sensors, electronically detecting an agent bound to each of the plurality of sensors, wherein the electrical circuit provides a sensor output responsive to a mechanical resonance frequency of the sensor, wherein the mechanical resonance frequency of the sensor is responsive to the binding of an agent to the functionalized membrane, and determining the mass of the agent bound to each of the plurality of sensors.

Abstract: A device and method for reducing and/or preventing fouling of a sensor is disclosed. The method comprises operating ultrasound technology that is submerged or partially submerged into a liquid medium that is responsible for the fouling. The device comprises the ultrasound technology itself. The ultrasound technology may be operated intermittently at high intensity to advantageously provide cavitation of the liquid medium, while avoiding the disadvantages typical of continuously operating ultrasound technology at high intensity. Additionally, the method may be carried out by taking advantage of the piezoelectric property of quartz.

Abstract: The present invention provides a standing wave fiber assembly for the collection and detection of a biological target in a complex biological fluid, including: an oscillator; and an elongated fiber coupled to the oscillator, wherein the elongated fiber is selectively exposed to a fluid potentially containing the biological target, and wherein the resonated elongated fiber attracts the biological target, and wherein a change in a response of the resonated elongated fiber indicates the presence of the biological target. The assembly also includes a top cover plate including one or more electrical connections and a port through which the fluid is introduced. The assembly further includes a bottom cover plate including a well in which the fluid is contained. Optionally, the elongated fiber includes one or more probes homogenously functionalized along its length that bind targeted biological materials.

Abstract: To provide a quartz sensor capable of detecting a sensing target with high sensitivity also in measurement in a liquid phase in which a difference in Q values at the time of measurement in the liquid phase and in a vapor phase is small. In a quartz sensor 1 including an AT-cut quartz plate 11 having a capture layer (absorbing layer) 12 formed on one surface (XZ? surface) thereof and detecting a sensing target based on an amount of change in a frequency of a quartz resonator 10 caused when the sensing target is absorbed by the capture layer 12, there are formed electrodes 13 for oscillating the quartz plate 11 on end faces (XY? surfaces) mutually opposite in a Z? direction of the surface of the quartz resonator 10 on which the capture layer 12 is formed (XZ? surface).

Abstract: Methods and systems for acoustically treating material using a continuous process in which material may be caused to flow in a continuous or intermittent fashion into/out of an acoustic treatment chamber where the material is exposed to focused acoustic energy. The methods and systems may be arranged to permit continuous processing for extended periods while an acoustic energy source operates at a relatively high power output. Treatment chambers may include features such as an acoustic window, a heat exchanger, inlet/outlet flow arrangements, an inspection window, insert elements that define a treatment volume size or shape, etc. Treatment system configurations relating to arrangements of a treatment chamber relative to an acoustic source and coupling medium, material flow paths, and others are provided.

Abstract: A method for measuring the properties of a fluid that uses a torsionally resonant structure having a base structure; at least two parallel tines affixed to the base structure and projecting in the same direction from the base structure; and wherein the base structure is sufficiently compliant as to mutually couple the tines so that they behave as a single resonator when the tines are driven in synchronized manner. The torsionally resonant structure is immersed in the fluid to be measured and a tine driving mechanism is used to drive the tines torsionally. A tine movement sensing mechanism form measurements of tine movement response to the driving mechanism and the measurements of tine movement to form measurements of fluid properties.

Abstract: Methods are provided for analyzing characteristics of fluids in the context of an acoustic ejection system. Such a system has a controller, an acoustic radiation generator, and a coupling medium coupling the radiation to a reservoir holding fluid. The methods can use acoustic radiation to both perturb a surface of the fluid in the reservoir and analyze the effect of the perturbation. The methods may use information about prior fluids. The methods of the invention can determine physical characteristics such as speed of sound and viscosity. The methods also include ways to determine a level of acoustic energy suitable to eject a droplet. Preferably the methods are executed automatically under control of programming of a controller of an acoustic ejection system.

Abstract: An ultrasonic transducer for use in a fluid medium. The ultrasonic transducer includes at least one housing and at least one transducer core at least partially accommodated in the housing. The transducer core includes at least one acoustic-electric transducer element. At least one damping material is also accommodated in the housing. The damping material includes at least one matrix material, at least one first filler introduced into the matrix material, and at least one second filler introduced into the matrix material. The first filler has a lower specific gravity than the matrix material. The second filler has a higher specific gravity than the matrix material.

Abstract: The present invention is directed to a cartridge device for a measuring system for measuring viscoelastic characteristics of a sample liquid, in particular a blood sample, comprising a cartridge body having at least one measurement cavity formed therein and having at least one probe element arranged in said at least one measurement cavity for performing a test on said sample liquid; and a cover being attachable on said cartridge body; wherein said cover covers at least partially said at least one measurement cavity and forms a retaining element for retaining said probe element in a predetermined position within said at least one measurement cavity. The invention is directed to a measurement system and a method for measuring viscoelastic characteristics of a sample liquid.

Abstract: The invention relates to a measuring device (10, 50) comprising a resonator (20, 52) having a sensitive region and a base support unit (26, 30) for measuring properties of a fluid, the resonator (20, 52) being inserted in the base support unit (26, 30) and contacted therein, the sensitive region remaining accessible to the fluid, and the resonator (20, 52) being activatable via connection points (24, 40) on the base support unit (26, 30). The invention is characterized in that the base support unit (26, 30) is formed solely by a film arrangement.

Abstract: A detection device (10) includes: covers (1-3); an oscillator (4); antennas (9, 11, 12), a testing space (13), and a minute space (14). The testing space (13) and minute space (14) are formed in the covers (1-3). The minute space (14) is open to the testing space (13). The oscillator (4) is disposed in the testing space (13) such that its edge portions are inserted into the minute space (14). The antenna (9) works together with the antenna (12) to apply an electromagnetic field to the oscillator (4). The antenna (11) works together with the antenna (12) to receive a reception signal composed of a vibration signal from the oscillator (4).

Abstract: Disclosed is a method of investigating the conformation of biomolecules or changes in the conformation of biomolecules as a result of an interaction, in which biomolecules from a sample of biomolecules are adhered discretely to the sensing surface of an acoustic wave sensor operating in a liquid, and a conformation parameter which is related to the conformation of the biomolecules from the said sample which are adhered discretely to the sensing surface, but substantially independent of the resulting change in mass loading of the sensing surface, is calculated from the resulting change in the output signals of the acoustic wave sensor. The conformation parameter may the acoustic ratio or a parameter which is directly related to the acoustic ratio.

Abstract: A method of determining a steam quality of a wet steam located in an interior of a steam turbine includes emitting from an optical probe a plurality of wavelengths through the wet steam, measuring with the optical probe a wet steam intensity corresponding to each of the plurality of wavelengths emitted through the wet steam, determining an intensity ratio vector by dividing the wet steam intensity by a corresponding dry steam intensity for each of the plurality of wavelengths, successively applying scaling factors to the intensity ratio vector to obtain a scaled intensity ratio vector, calculating a suitable value for each of the scaling factors to obtain a plurality of residuals, determining a minimum residual of the plurality of residuals, determining a droplet size distribution by calculating the droplet number density corresponding to the minimum residual, and determining the steam quality based on the droplet size distribution.

Abstract: A method for analyzing liquid samples may comprise applying a liquid to a cMUT device having a plurality of sensors, drying the plurality of sensors, electronically detecting an agent bound to each of the plurality of sensors, wherein the electrical circuit provides a sensor output responsive to a mechanical resonance frequency of the sensor, wherein the mechanical resonance frequency of the sensor is responsive to the binding of an agent to the functionalized membrane, and determining the mass of the agent bound to each of the plurality of sensors.

Abstract: Measurements of the mass and surface charge of microparticles are employed in the characterization of many types of colloidal dispersions. The suspended microchannel resonator (SMR) is capable of measuring individual particle masses with femtogram resolution. The high sensitivity of the SMR resonance frequency to changes in particle position in the SMR channel is employed to determine the electrophoretic mobility of discrete particles in an applied electric field. When an oscillating electric field is applied to the suspended microchannel, the transient resonance frequency shift corresponding to a particle transit can be analyzed to extract both the buoyant mass and electrophoretic mobility of each particle. These parameters, together with the mean particle density, can be used to compute the size, absolute mass, and surface charge of discrete particles.

Abstract: Nonlinear sensors, which actively exploit dynamic transitions across sub-critical or saddlenode bifurcations in the device's frequency response, can exhibit improved performance metrics and operate effectively at smaller scales. This sensing approach directly exploits chemomechanically induced amplitude shifts for detection. Accordingly, it has the potential to eliminate the need for numerous power-consuming signal processing components in final sensor implementations. Various embodiments pertain to low-cost, linear and nonlinear bifurcation-based mass sensors founded upon selectively functionalized, piezoelectrically actuated microcantilevers. Yet other embodiments pertain to an amplitude-based sensing approach based upon dynamic transitions across saddle-node bifurcations that exist in a sensor's nonlinear frequency response.

Abstract: A detection device (10) includes: covers (1-3); an oscillator (4); antennas (9, 11, 12), a testing space (13), and a minute space (14). The testing space (13) and minute space (14) are formed in the covers (1-3). The minute space (14) is open to the testing space (13). The oscillator (4) is disposed in the testing space (13) such that its edge portions are inserted into the minute space (14). The antenna (9) works together with the antenna (12) to apply an electromagnetic field to the oscillator (4). The antenna (11) works together with the antenna (12) to receive a reception signal composed of a vibration signal from the oscillator (4).

Abstract: A method comprising preparing a baseline cement slurry comprising a cement, water, and one or more additives, placing a sample of the baseline cement slurry into a sample container having a vertical height, and measuring time of flight of energy through the sample at one or more locations along the vertical height to determine a settling property of the baseline cement slurry. A method comprising providing a settling test apparatus comprising a column having a vertical height and at least one pair of transducers positioned opposite each other with the column there between, placing a cement slurry sample within the column, and measuring time of flight of ultrasonic energy through the sample at one or more locations along the vertical height to determine a settling property of the cement slurry.

Abstract: This disclosure relates to detecting fluid in medical tubing. In certain aspects, a method is performed by a data processing apparatus. The method includes controlling repetitive activation of the ultrasonic transmitter. The method also includes receiving a signal from the ultrasonic receiver during an activation of the ultrasonic transmitter. The method also includes determining that fluid is absent or present in a portion of the medical fluid tube based on a comparison between the signal and a threshold value.

Abstract: A method of using photoacoustic spectroscopy to determine chemical information about an analyte includes the steps of emitting a light ray for interaction with a sample of an analyte; transmitting the light ray through a fill fluid disposed in a detection cell, the fill fluid having molecules substantially similar to molecules of the analyte to absorb the light ray; producing a thermal wave and oscillation in the fill fluid proportional to an intensity of the light ray; including a pressure oscillation in the fill fluid by the thermal wave; and detecting the pressure oscillation by a microphone to determine information about the analyte sample.

Abstract: A resonator in the fluid for displacing the fluid has a sensing section and a non-sensing section. A compression contact member coupled to the mounting body compressively secures the resonator non-sensing section in a mounting body. The apparatus may further include a pressure feed through module received in the mounting body that is in signal communication with the resonator.

Abstract: An apparatus for determining and/or monitoring at least one process variable of a medium. The apparatus includes: at least one mechanically oscillatable unit; a driving/receiving unit, which, starting with an electric, excitation signal, excites the mechanically oscillatable unit to execute mechanical oscillations, and which receives the mechanical oscillations of the mechanically oscillatable unit and converts them into an electric, received signal; and an electronics unit, which, starting with the electric, received signal, generates the electric, excitation signal and sends it to the driving/receiving unit. The electronics unit is embodied in such a way that it generates the excitation signal, such that a predeterminable phase difference exists between the excitation signal and the received signal. Present in the electronics unit is at least one all-pass filter for tuning the phase difference.

Abstract: A surface acoustic wave sensor device includes a main body and a liquid controller disposed external to the main body. The main body includes a sample chamber, a surface acoustic wave sensor connected to the sample chamber, a first disposal chamber connected to the surface acoustic wave sensor and channels connecting the sample chamber, the surface acoustic wave sensor and the first disposal chamber. The liquid controller controls flow of a sample through the main body.

Abstract: Disclosed is a liquid analysis apparatus (100), whereby wireless communication is reliably performed without having electromagnetic wave signals attenuated in a liquid, and the characteristics of the liquid can be simply and rapidly analyzed.

Abstract: Described herein are a device and method for measuring the wetting characteristics of a liquid on a surface of a material by depositing a volume of liquid on the surface of the material, imparting kinetic energy to the liquid, and obtaining information about the geometry of the volume of the liquid on the surface. The device includes a liquid dispensing component, a kinetic energy imparting component, a position determining component, and a data generating component.

Abstract: Method and system for uniformly spacing particles in a flowing system comprising suspending particles in an elongated fluid filled cavity; exposing said cavity to an axial acoustic standing wave field, wherein said axial acoustic standing wave field drives said particles to nodal and anti-nodal positions along the center axis of said cavity to result in uniformly spaced particles; and focusing said particles to the center axis of said cavity.

Abstract: Methods and apparatus for non-invasive, simultaneous determination of density and a shear resistance relating variable of a non-gaseous, free flowing material are presented. In one example, the non-gaseous free flowing material is disposed within a vessel at a known or constant level. According to this example, the method and apparatus utilizes an adjustable mathematical model to determine the density and a shear resistance relating variable based on measurements of the system comprising the filling material, the vessel wall and the dynamic measuring instrument interacting with the wall.

Abstract: Time-series data of piezoelectric resonator frequencies for each concentration of a substance to be absorbed is collectively displayed. An absorption start point of a substance to be absorbed is set in pieces of the time-series data. An editor combines and displays at least frequency variation regions in the data. The absorption start point setting is realized when an operator positions a pointer and clicks on the time-series data, or when an absorption start signal is output at the time when a solution is supplied.

Abstract: An in-liquid-substance detection sensor that achieves size reduction and detection accuracy improvement includes a piezoelectric substrate, at least two SAW devices provided on one major surface of the piezoelectric substrate and each having at least one IDT electrode defining a sensing portion, outer electrodes provided on the other major surface of the piezoelectric substrate and electrically connected to the SAW devices through vias extending through the piezoelectric substrate, a channel-defining member provided on the one major surface of the piezoelectric substrate so as to surround the SAW devices and a region connecting the SAW devices to each other, thereby defining sidewalls of a channel, and a protective member bonded to the one major surface of the piezoelectric substrate with the channel-defining member interposed therebetween, thereby sealing the channel, the protective member having at least two through holes communicating with the channel.

Abstract: Disclosed is a wave sensor apparatus including a unit for removing a gas and a method of detecting a target material in a liquid sample, the method including removing a gas in the liquid sample.

Abstract: This disclosure concerns a cytometry system including a handling system that enables presentation of single cells to at least one laser source. The laser source is configured to deliver light to a cell within the cells in order to induce bond vibrations in the cellular DNA. The system further includes a detection facility that detects the signature of the bond vibrations, wherein the bond vibration signature is used to calculate a DNA content carried by the cell.

Abstract: A method for detecting cavitation in a hydrostatic system includes capturing an oscillation typical for the cavitation from a pressure captured over time. Furthermore, the method includes establishing an evaluation variable for cavitation on the basis of the captured oscillation. Additionally, the method includes comparing the evaluation variable to a comparison value.

Abstract: A method for determining a physical property of an object or fluid in a dynamic multi-path clutter environment comprises transmitting an RF interrogation signal to a wireless sensor physically coupled to the object or fluid (gas or liquid) in the dynamic multi-path clutter environment, wherein the wireless sensor is operable to receive the RF interrogation signal, produce a reference signal and a measurement signal, and retransmit the reference signal and the measurement signal in the dynamic multi-path clutter environment. The reference signal and measurement signal are delayed by the wireless sensor by an amount of time that may be a function of the unknown physical property. The method also comprises receiving the retransmitted reference signal and the retransmitted measurement signal and comparing them in the time domain in order to determine the unknown physical property of the object or fluid.

Abstract: The invention relates to an apparatus comprising a measurement chamber and a resonator, which can be integrated in the measurement chamber via a quick-action closure, for the liquid sensor system and for verification and measurement of the concentration of materials, substances, particles and/or microorganisms in liquids. The invention is characterized in that the resonator is held only on its outer circumference by a thin elastomer ring, and in that at the radial distance of the external diameter of the resonator, the elastomer ring on the one hand rests on an upper sealing ring of the measurement chamber, forming a seal, and on the other hand rests on a holding ring.

Abstract: Methods for improving measurements of bacterial growth, such as mass, in Suspended Microchannel Resonators (SMR's). Methods include techniques to provide for bacterial growth over time in response to changing fluid environment to aid in determining parameters such as drug resistance and drug susceptibility. In particular the methods include trapping multiple bacteria in the SMR for a time period and varying the fluid to include sequences of nutrients and antibiotics, and measuring the rate of mass change of the bacteria in response to the changes in fluid composition.

Abstract: A sensor array for viscosity measurement includes the following: a carrier substrate formed with an opening; a metal plate-shaped oscillating element disposed on a surface of the carrier substrate and parallel to the surface over the opening; at least two metal contact electrodes disposed on the carrier substrate; at least two metal spring elements, wherein each of the contact electrodes is connected to the oscillating element by way of a spring element such that the element is mounted on the carrier substrate by way of the spring elements; and a magnet, which is disposed in the vicinity of the carrier substrate such that the magnetic field lines penetrate the plate-shaped oscillating element.

Abstract: There is provided a technique that can increase sensitivity of a resonator. A ratio Rb/Ra between an inner diameter Rb and an outer diameter Ra of the resonator 20 is appropriately selected, and thus there may be a fixed point where an r component (U(Ra) or U(Rb)) of displacement in a radial direction and an r component (V(Ra) or V(Rb)) of displacement in a tangential direction are 0 on an outer diameter portion or an inner diameter portion of the resonator 20. In this case, the resonator 20 is supported by a holding member 22 constituted by a single-span beam set so that a boundary condition on a side of the resonator 20 is pinned and a boundary condition on a side of an anchor that supports the resonator 20 is clamped at the fixed point, and this prevents vibration energy of the resonator 20 from being lost through the holding member 22, avoids a state to disturb a vibration mode, and achieves a sensor having high sensitivity.

Abstract: Method and system for background suppression in magneto-motive photoacoustic imaging of labeled target objects.

Abstract: A piezoelectric sensor senses a substance to be measured in a sample solution, thereby conducting high-precision measurement. A pressing member has a solution storage space with a bottom surface being one surface of a piezoelectric resonator, and covering a recessed portion of a wiring board. The wiring board includes an annular projection surrounding the solution storage space and pressing a surface of the piezoelectric resonator. The wiring board is made of an elastic material. The annular projection has side surfaces that get smaller in diameter toward a lower side. The side surface of the solution storage space makes an obtuse angle to its bottom surface. At a corner portion made by these surfaces, an upper side of the bubbles are opened, and therefore, bubbles, even if entering the solution storage space, can float up.

Abstract: To provide a piezoelectric sensor in which a first electrode for measurement and a second electrode for reference are provided apart from each other on one surface side of a piezoelectric piece and a common electrode is provided on an opposite surface side so as to face the first and second electrodes. A piezoelectric sensor includes: a first electrode for measurement and a second electrode for reference provided apart from each other on one surface side of a piezoelectric piece; a common electrode provided on an opposite surface side of the piezoelectric piece commonly for the first electrode and the second electrode to face the first electrode and the second electrode; and an adsorption layer formed on an area, of the common electrode, to which the first electrode is faced across the piezoelectric piece, to adsorb a substance to be sensed.

Abstract: A system for detecting a presence of a liquid within a receptacle includes a sensor and a processor. The sensor includes a transmitting probe and a receiving probe positioned within the liquid receptacle. The transmitting probe includes a first transducer and the receiving probe includes a second transducer. The processor is in electrical communication with the first and second transducers and monitors the first and second transducers to determine the presence and level of the liquid within the liquid receptacle based on a time between generation of a first extensional wave by the first transducer and reception of a second extensional wave by the second transducer.

Abstract: A liquid dispensing apparatus for dispensing droplets of a liquid, and methods for measuring various fluid parameters of the liquid are described. The liquid dispensing apparatus comprises a container having a chamber for holding a liquid. An orifice is positioned at an end of the chamber for dispensing droplets of the liquid, the orifice being configured to retain the liquid in the container if the container is positioned with the orifice facing in a downward direction. An acoustic transducer means is at least partially positioned in the chamber for periodically propagating a focused acoustic beam toward the orifice and through at least some of the liquid while the liquid is contained in the chamber, with the focused acoustic beam being capable of causing a droplet of the liquid to be ejected from the orifice when a free surface of the liquid is within the depth of field of the acoustic transducer means.

Abstract: Vibrating wire viscometers are disclosed. An example apparatus to determine the viscosity of a downhole fluid is described, the apparatus including a wire to be immersed in a downhole fluid, to vibrate when an alternating current is applied to the wire within a magnetic field, and to generate an electromotive force when vibrating within the magnetic field, the wire comprising a first resistance. The apparatus further includes a nulling circuit coupled to the wire, wherein the nulling circuit comprises a second resistance that is selectable to be substantially equal to the first resistance, and an analyzer coupled to the wire and the nulling circuit to determine the first resistance, the second resistance, and a viscosity of the downhole fluid based on the first and second resistances, at least one characteristic of the wire, and the electromotive force.

Abstract: A piezoelectric resonator for use in a sensor arrangement for detecting or measuring an analyte in a medium, comprises a quartz crystal plate, having a first crystal surface and a second crystal surface. The first crystal surface is provided with a first electrode, which has a surface area of less than 15 mm2 and the second crystal surface is provided with a second electrode. The first electrode may have a rectangular surface shape. A flow cell for use in an apparatus for detecting or measuring an analyte in a medium, comprises walls that form a sensing chamber together with the resonator, and inlet and outlet openings for leading a fluid through the sensing chamber. A part of the resonator constitutes one of the walls of the sensing chamber and is arranged such that the first electrode is situated inside the sensing chamber.

Abstract: A method for ascertaining and/or monitoring a process variable, wherein a time-limited, exciting signal, which is described by at least one desired quantity, or by a desired signal form, is applied to a first piezoelectric element, or to a first polarized zone of a piezoelectric element. The response signal, which is described by at least one actual quantity, or actual signal form, corresponding, respectively, to the desired quantity, or desired signal form, is registered by a second piezoelectric element, or by a second polarized zone of the piezoelectric element, wherein the actual quantity, or the actual signal form, of the response signal and the desired quantity, or the designed signal form, of the response signal are compared with one another. On the basis of the ultrasonic measuring signal, which is describable by the defined desired quantity, or the defined, desired signal form, the process variable is ascertained via a sound-entrainment method or via an echo method.

Abstract: An apparatus determines the properties of a medium in the form of a fluid or soft material. An acoustic waveguide has two opposing guide elements delimiting an interior space to be filled with a medium. The guide elements, upon filling the interior space with a medium, form an interface with the medium with an inner surface. A transmitter generates acoustic surface waves in the waveguide, which are received by a receiver. The waveguide can be coupled with an evaluation unit for determining physical properties of the medium based on a signal generated by the receiver. A housing accommodates the guide elements, transmitter and receiver. On the respective inner surface, at least a part of the acoustic surface waves can be converted into volumetric sound waves of the medium and at least a part of the volumetric sound waves can be converted into acoustic surface waves of the waveguide.