Abstract: The present invention provides systems, methods, and devices for using acoustic energy. In some embodiments, a fluid bath may be provided in the system where the fluid bath quality may be monitored using acoustic energy. An assessment of fluid bath quality can be determined through a comparison that is made of an initial power signal of the acoustic energy with a reflected power signal of the acoustic energy.

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: A flow analysis flow analysis system having a deaerator for removing gas bubbles in a liquid upstream an analysis section. The deaerator comprises a liquid-containing means variable in internal volume for containing the liquid together with gas bubbles included in the liquid; a liquid-introducing means for introducing the liquid into the liquid-containing means; a gas bubble-discharging means for discharging gas bubbles in the liquid-containing means by decreasing the internal volume of the liquid-containing means while maintaining in the liquid-containing means at least part of the liquid introduced by the liquid-introducing means; and a liquid delivery means for delivering to the analysis section the liquid in the liquid-containing means from which gas bubbles have been discharged by the gas bubble-discharging means.

Abstract: A microelectromechanical system comprises a deformable portion and at least one stress sensor fixedly attached to the deformable portion. The sensor itself comprises a base portion and a shunt portion juxtaposed on the deformable portion, and connections arranged to detect a change of a distribution of an electric current in the base and shunt portions. Such a system is suitable for many applications, in particular for forming a portion of an arm of an atomic force microscope or for entering into the constitution of a bio sensor.

Abstract: The present invention relates generally to a signal amplification method for a SAW resonator microsensor for analyzing test samples, containing target analyte including proteins and nucleic acids. The invention relates to at least one surface acoustic wave resonator unit comprising a plurality of three-dimensional interdigital transducer electrode (IDTE) and reflector micro channels located on a piezoelectric substrate surface. The invention further relates to a change of solid/liquid volume ratio in said three-dimensional micro channels; said changes of the liquid/solid volume ratio can be directed correlated to the target analyte concentration in a test sample.

Abstract: Fluid sensor methods and systems adapted for monitoring and/or controlling distillation operations in fluidic systems, such as batch distillation operations or continuous distillation operations, are disclosed. Preferred embodiments are directed to process monitoring and/or process control for unit operations involving endpoint determination of a distillation, for example, as applied to a liquid-component-switching operation (e.g., a solvent switching operation), a liquid-liquid separation operation, a solute concentration operation, a dispersed-phase concentration operation, among others.

Abstract: A sensor is provided which is configured to detect the presence of multiple analytes, for example chemical or biological compounds, through the measurement of induced resonance shifts in a coupled array of microelectromechanical or micromechanical resonators.

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.

Abstract: Highly sensitive sensor platforms for the detection of specific reagents, such as chromate, gasoline and biological species, using microcantilevers and other microelectromechanical systems (MEMS) whose surfaces have been modified with photochemically attached organic monolayers, such as self-assembled monolayers (SAM), or gold-thiol surface linkage are taught. The microcantilever sensors use photochemical hydrosilylation to modify silicon surfaces and gold-thiol chemistry to modify metallic surfaces thereby enabling individual microcantilevers in multicantilever array chips to be modified separately. Terminal vinyl substituted hydrocarbons with a variety of molecular recognition sites can be attached to the surface of silicon via the photochemical hydrosilylation process.

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 flexural resonator includes a piezoelectric material. At least a portion of an electrode having a first surface and a second surface is embedded in the piezoelectric material such that the piezoelectric material is disposed over and in electronic association with the first and second surfaces of the electrode.

Abstract: The present invention prevents instability of frequency measurement caused by spatial connection between quartz sensors adjacent to each other when a plurality of quartz sensors, including a quartz resonator which varies a national frequency due to adsorption of an object, are to be detected. A common measuring unit measures a variation in frequency of each oscillation circuit corresponding to each quartz sensor by switching and connection in turn, and the oscillation circuits, excepting an oscillation circuit connected to the measuring unit by switches, are connected to a load on the output side of the oscillation circuit channels connected to the measuring unit and the load value is such that the respective oscillating frequencies are forcibly separated from each other.

Abstract: Systems and methods for thermally actuating piezoresistive cantilevers are described. One embodiment includes a nanoelectromechanical resonator connected in at least one location to a substrate, an electrically conductive path formed on the resonator and a signal source connected to the electrically conductive path and configured to provide an oscillating actuation signal capable of exciting a resonant mode in the resonator.

Abstract: A reservoir for use in testing a liquid as part of a microfluidic testing system, includes a testing chamber configured to receive the liquid to be tested. A liquid inlet is fluidly coupled to the testing chamber to allow ingress of the liquid into the testing chamber. A gas outlet is fluidly coupled to the testing chamber to allow egress of gas out of the testing chamber. The gas outlet has an elevation that is higher than an elevation of the liquid inlet such that, as the testing chamber is rotated, the gas is expelled out of the testing chamber through the gas outlet, thereby reducing or preventing a presence of gas bubbles in the liquid.

Abstract: A method and apparatus for providing, e.g., identifying or determining, at least one parameter of a fluid moving through a fluid channel using a vibrating wire in contact with the fluid moving through the fluid channel that is clamped under tension. The vibrating wire is actuated by an actuating device capable of displacing the vibrating wire from an initial position. An interpretation element further is utilized to provide a parameter of the fluid moving through the fluid channel based upon data from the vibrating wire following actuation by the actuation element.

Abstract: A fuel cell system including a quartz crystal microbalance (QCM) concentration sensor, and in particular, comprising a bypass channel structure useful for installing a QCM concentration sensor to a fuel cell system. The fuel cell system includes a fuel cell stack generating electric energy by an electrochemical reaction of a hydrogen-containing fuel and an oxidant, a fuel cell including a fuel supplying unit supplying the hydrogen-containing fuel to the fuel cell stack, a QCM concentration sensing unit for measuring the concentration of a fluid in the fuel cell, and a drive controlling unit for controlling the operation of the fuel cell according to an output of the QCM concentration sensing unit.

Abstract: A cartridge for apparatus for analysing a sample comprising a fluid as a flow cell for receiving the sample. The cell is formed from a substantially rigid support surface (102), a sensor comprising an electrical mechanical transducer (92), for example a wafer of quartz crystal and adhesive means, such as double sided adhesive tape (100) attaching the sensor to the support surface. The support surface and sensor are spaced from each other by a membrane, which may form part of the double sides adhesive tape so as to define the flow cell between the support surface and the sensor. The flow cell also has an opening (for example, 111) through which, in use, the sample passes. The sensor, forming part of the flow cell, comes into contact with the sample to enable the sample to be analysed.

Abstract: Techniques for evaluating physical aspects of a formation fluid from within a wellbore include changing pressure on a sample of the formation fluid and transmitting at least one acoustic pulse through the fluid sample and analyzing acoustic information collected. Apparatus and methods for the evaluating involve using at least one acoustic transducer. Analyzing typically involves use of formulae that relate the fluid's equation of state and other properties to a change in the sound speed in the fluid as a function of pressure.

Abstract: A sensor system and method for analyzing a fluid contained within an environmental control system, comprising the steps of providing a system including a passage for containing a thermal change fluid; placing a sensor including a mechanical resonator in the passage; operating the resonator to have at least a portion thereof translate through the fluid; and monitoring the response of the resonator to the fluid in the passage. A preferred sensor includes a tuning fork resonator.

Abstract: An acoustic wave sensor array device is provided for the detection, identification, and quantification of chemicals and biological elements dispersed in fluids. The sensor array device is capable of the simultaneous characterization of a fluid for multiple analytes of interest. A substrate has a plurality of channels formed therein and a sensor material layer applied in a bottom of the channels. The sensor material layer has a shear acoustic wave speed lower than a shear acoustic wave speed in said substrate. The channels may have the same material in each channel or different materials in at least two of the channels. A surface acoustic wave transducer and at least one surface acoustic wave reflector, or at least two transducers is formed on a surface of the substrate opposite the channels at a portion of the substrate that is thinned by the channels, so that the acoustic tracks of the surface acoustic wave device extend along the channels.

Abstract: Method for measuring a target particle property. A suspended microchannel resonator is calibrated to determine the relationship between a detected mass and a resonance frequency shift of the resonator. The target particle is suspended in a fluid and introduced into the resonator, and the resonator frequency shift due to the particle is measured. Target particle mass is calculated from the resonator frequency shift, the target particle density, and the fluid density. A target particle property such as size or volume is determined from the calculated target particle mass.

Abstract: A method for determining the concentration of a large particle component in a multi-component system. The method requires first separating and concentrating the large particle component of the system by acoustic means and then measuring an acoustical parameter of the separated large particle component. The invention also provides for an apparatus for determining the concentration of large particles in a multi-component fluid system. The apparatus is comprised of an acoustic standing wave resonator, at least one acoustic standing wave generating source, electronic circuitry for actuating, controlling and processing the acoustic standing wave generating source and means for measuring at least one parameter of the multi-component system after the large particles have been concentrated and aggregated by the generated standing wave(s).

Abstract: The invention provides devices and methods for acoustically determining the properties of the contents of one or more reservoirs in a plurality of reservoirs. Each reservoir is adapted to contain a fluid. An acoustic radiation generator can be positioned in acoustic coupling relationship to each of the reservoirs. Acoustic radiation generated by the acoustic radiation generator is transmitted through each reservoir to an analyzer. The analyzer is capable of analyzing a characteristic of the transmitted acoustic radiation and optionally correlating the characteristic to a property of the reservoirs' contents. Properties that may be determined include volume, temperature, and composition. The invention is particularly suited to determining the properties of the contents of a plurality of reservoirs to allow for accuracy and control over the dispensing of fluids therefrom.

Abstract: In a sensor for detecting a substance in liquid, recesses are provided in the upper surface of a base substrate. The recesses respectively accommodate SAW elements. A resin layer having openings is arranged such that the sensing portions at the upper surfaces of the SAW elements are exposed in the openings. A reaction film made of a material capable of binding to a target substance is also arranged so as to cover the sensing portion of at least one of the SAW elements. A liquid containing a target substance is fed from the openings.

Abstract: A reservoir for use in testing a liquid as part of a microfluidic testing system, includes a testing chamber configured to receive the liquid to be tested. A liquid inlet is fluidly coupled to the testing chamber to allow ingress of the liquid into the testing chamber. A gas outlet is fluidly coupled to the testing chamber to allow egress of gas out of the testing chamber. The gas outlet has an elevation that is higher than an elevation of the liquid inlet such that, as the testing chamber is rotated, the gas is expelled out of the testing chamber through the gas outlet, thereby reducing or preventing a presence of gas bubbles in the liquid.

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: A concentration measuring apparatus includes a vibration member; a shielding unit that limits a flowable area of a solution to be measured close to the vibration member; a vibration control unit that vibrates the vibration member at a frequency; a variation measuring unit that measures a physical variation of the vibration member vibrated; an eigenfrequency computing unit that computes an eigenfrequency of the vibration member in the solution from the frequency and the variation; and a concentration obtaining unit that obtains a concentration of the solution from the eigenfrequency and a correspondence between the eigenfrequency and the concentration of the solution.

Abstract: A mechanical resonator capable of providing an intrinsically high mechanical quality factor in immersion is provided. The resonator includes a membrane attached at its perimeter to a frame, such that a front side of the membrane is in contact with the liquid, and the back side of the membrane is not in contact with the liquid or the frame. The membrane can act as a mechanical resonator. The quality factor of this resonator is enhanced by providing a pressure release boundary region on the frame in proximity to the membrane and in contact with the liquid. The pressure release boundary region provides a soft boundary condition, in the sense that a mechanical impedance on the solid side of the solid-liquid interface is less than the liquid mechanical impedance. Providing such a soft boundary condition reduces the mechanical energy loss due to excitation of waves in the liquid, thereby improving resonator quality factor. Such high-Q resonators are particularly useful for sensor applications.

Abstract: Prefabricated catalyzing adsorption sites are incorporated into small oscillators. In one embodiment, the sites are formed of precisely positioned gold anchors on surface micromachined oscillators. The micromachined oscillators may be formed of silicon, such as polysilicon, or silicon nitride in various embodiments. The sites allow special control of chemical surface functionality for the detection of analytes of interest. Thiolate molecules may be adsorbed from solution onto the gold anchors, creating a dense thiol monolayer with a tail end group pointing outwards from the surface of the gold anchor. This results in a thiolate self-assembled monolayer (SAM), creating a strong interaction between the functional group and the gold anchor.

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: A method and apparatus for testing a hydrocarbon sample. The apparatus includes a sheath disposed about the hydrocarbon sample container and at least one set of acoustic sensors, wherein the at least one set of acoustic sensors is secured to the sheath, and further wherein at least one set of acoustic sensors produces an acoustic signal having a velocity through the hydrocarbon sample. In addition, the velocity is measured to provide information about the hydrocarbon sample. In other embodiments, the at least one set of acoustic sensors is disposed radially about the hydrocarbon sample.

Abstract: A sensor for detecting an analyte in liquid includes a base substrate provided with openings and electrode lands on one surface thereof and SAW elements each provided with a sensing portion having at least one IDT electrode on one side. The SAW elements are mounted on the base substrate with bump electrodes by a flip-chip bonding method so that the sensing portions of the SAW elements face the openings of the base substrate. At least one of the sensing portions is coated with a reaction membrane which binds to an analyte.

Abstract: A cooking oil quality sensing apparatus and system includes an acoustic wave sensor composed of one or more acoustic wave transducers configured upon a piezoelectric substrate such that when the acoustic wave sensor is in contact with cooking oil, the sensor generates acoustic wave data indicative of the quality of the cooking oil. An antenna can be integrated with the acoustic wave sensor, such that the antenna receives data an external source and transmits the acoustic wave data indicative of the quality of the cooking oil to the external source. An oscillator can be integrated with the acoustic wave sensor, such that the output of the oscillator contains data indicative of the quality of the cooking oil. The acoustic wave sensor can be coated with a material that is selectively sensitive and/or reactive to one or more fatty acids associated with or contained in the cooking oil.

Abstract: A sensor is provided which is configured to detect the presence of multiple analytes, for example chemical or biological compounds, through the measurement of induced resonance shifts in a coupled array of microelectromechanical or micromechanical resonators.

Abstract: A method for analysis of a multi-component fluid is provided based on the features of the dynamics of the self-organization processes in drying drops. An electro-acoustic resonator is utilized, with a drop of multi-component fluid placed on one end of the resonator. A shear oscillation is imparting to the resonator along its longitudinal axis. And oscillating electric voltage is placed across the resonator generally perpendicular to the direction of mechanical oscillation. Changes in the electrical conductance corresponding to changes in the acoustical-mechanical impedance can thereby be measured as the drop of multi-component liquid dries. The particular geometry of an amplitude curve includes identifying the spatio-temporal development and phase transitions is used for integral estimation of food authenticity and quality.

Abstract: A method for measuring changes in the composition of fluids, for medical diagnostics or quality control of fluids, comprising: One) placing a drop of fluid upon a quartz crystal; Two) generating ultrasonic vibrations of a predetermined frequency in the crystal; with the vibrating wave directed into the drop of fluid in a vertical direction relative to the area of the crystal upon which the drop is placed; Three) measuring voltage changes over a bridge circuit connected to the crystal, over a time period during which total or partial evaporation of the liquid occurs; Four) comparing the measurement result to previously obtained results or to predetermined data; Five) detecting changes in the composition of the fluid, from the results. detecting changes in the composition of the fluid, from said results.

Abstract: A measurement method and a biosensor apparatus using a resonator with which it is not necessary to agitate a sample solution in a cell and even if the amount of the sample solution is very small the influence of pressure waves is greatly reduced and extremely easy and accurate measurement is possible. In a method of the kind wherein a sample solution is brought into contact with one side of a resonator having first and second electrodes on opposite sides of a crystal plate and an a.c. signal is applied across the first and second electrodes and a frequency change of the resonator is measured from a relationship between the frequency of the a.c. signal and an electrical characteristic of the resonator, the resonator is made to oscillate at an N-tuple harmonic (N=3, 5, 7 . . . ) as the frequency change is measured.

Abstract: An apparatus for determining a characteristic such as sound speed for a fluid in a tube comprises means for applying a force to cause a change in a transverse dimension of a segment of the tube, wherein the change in the transverse dimension is reversible, and means for launching and receiving ultrasonic signals. Ultrasonic signals propagate through the tube along paths of different lengths. At least one of the paths is located entirely within the segment having the changed transverse dimension. The applied force may cause the transverse dimension to change continuously or in discrete steps. Path length differences between the paths are determined, and transit times are determined for each of the ultrasonic signals. The characteristic is determined based on information comprising the path length differences and the transit times.

Abstract: The invention relates to a cell for measuring acoustical properties of a fluid sample comprising cell body having first and second opposite substantially flat end faces and forming at least one sample cavity for receiving a sample to be investigated and first and second electro-acoustical transducer wafers each having first and second main surfaces, said first main surface of said first and second transducers being positioned at said first and second end surfaces respectively, of said cell body. The invention proposes to provide at least one sealing means at one end face.

Abstract: A system and method for determining the atomization characteristics of fluids being emitted by a nozzle is disclosed. In one embodiment, a fluid is emitted through a nozzle while simultaneously sensing vibrations occurring within the nozzle. The vibrations provide information about the atomization characteristics of the fluid. By comparing the sensed vibrations to vibration patterns produced by known fluids through the same or a similar nozzle, the atomization characteristics of the fluid being tested can be predicted. In one embodiment, for instance, the atomization characteristics of a fluid may be determined as a function of velocity or flow rate through the nozzle.

Abstract: A miniaturized sensor device comprises at least one pair of active projecting elements or cantilevers, which are set parallel to one another and at a micrometric or sub-micrometric distance apart and are designed to be submerged at least partially in a fluid. Each pair comprises a first cantilever, equipped with actuator means, and a second cantilever, equipped with sensor means. The actuator means can cause a movement of the first cantilever, whilst the sensor means can detect a movement of the second cantilever, induced by the movement of the first cantilever, for generating accordingly a measurable signal, which represents the lubricating capacity of the fluid.

Abstract: A multiparameter acoustic signature inspection device and method are described for non-invasive inspection of containers. Dual acoustic signatures discriminate between various fluids and materials for identification of the same.

Abstract: The invention relates to a method and a device for the early detection of the presence of micro-organisms in food, particularly in milk and derivatives thereof. One of the main advantages of the invention lies in the fact that the aforementioned detection method can be performed inside the commercial packaging thereof without the need for said packaging to be opened. The presence of micro-organism is detected, before they can produce drastic changes in the physical properties of the product, according to changes in the propagation of elastic waves (velocity, attenuation and harmonic distortion) through the product and, moreover, different types of micro-organisms can be distinguished. The inventive detection method is performed under dry conditions and requires an environment with controlled humidity and temperature.

Abstract: A method and system for detecting oil quality. The quality of engine oil can be determined utilizing an acoustic wave sensor to obtain viscosity and corrosivity data associated with the engine oil. The acoustic wave sensor is coated with a material that selectively reacts to at least one type of an acid in order to provide data indicative of the presence of the acids in the engine oil. The etch rate or the corrosivity of the engine oil can be determined based on the frequency data obtained as a result of the frequency measurement utilizing the acoustic wave sensor. The viscosity of the engine oil can additionally be obtained based on a measurement of phase and amplitude obtained from the data utilizing the acoustic wave sensor. The etch rate and the viscosity measurement provide data indicative of the quality of the engine oil.

Abstract: An on-chip coil is provided in a micromachined device for magnetic actuation of a nanoelectromechanical microcantilever. The novel geometry involves a three dimensional solenoid or planar coil carrying high current that generates a large enough magnetic field in its close proximity to a permalloy thin film patch or columnar magnet disposed on the distal end of the piezoresistive microcantilever to effectively interacts with the magnetic thin film deposited on the microcantilever. The device comprises an effective actuators which can be integrated with biofunctionalized cantilever arrays in hybrid semiconductor-microfluidics devices for the analysis and detection of biological analytes.

Abstract: A device for determining and/or monitoring at least one physical parameter of a medium, having at least one mechanically oscillatable unit and at least one drive-/receive unit. The drive-/receive unit excites the oscillatable unit to oscillate, or, it receives the oscillations of the oscillatable unit, as the case may be. The invention includes that in the drive-/receive unit at least one piezo-drive is provided, which has at least one exterior surface. The exterior surface is composed of at least two segments of different polarization, wherein the directions of polarization are directed essentially opposite to one another. The mechanically oscillatable unit is directly or indirectly connected with the exterior surface, so that the mechanically oscillatable unit is excited to a movement, or so that the movement of the mechanically oscillatable unit is received. The movement always has at least two different force components.

Abstract: The disclosed sensor chip includes a substrate and a moving member coupled to the substrate and disposed for movement relative to the substrate. The moving member moves relative to the substrate in a first direction and in a second direction in response to movement of the substrate. The first direction is different than the second direction. The moving member includes a plurality of receptors. The receptors are configured for selectively binding to a first measurand.

Abstract: A fermention process is monitored by detecting ultrasound backscattered from the cells as a function of time. A transducer 46 is placed in a fermentor 30 and transmits ultrasound towards a reflecting surface 50. The transducer receives that portion of the ultrasound which reflects from the reflecting surface 50, as well as that portion of the ultrasound which backscatters from cells 34 between the transducer 46 and the reflecting surface 50. Signals from the transducer are conditioned and subsequently processed to provide output to a controller regarding the status of the fermentation process in real time. The backscattering measurements can be used to determine a growth phase transition, such as the transition between the logarithmic growth phase of the cells and their stationary phase.

Abstract: Circuitry adapted for carrying out associated techniques for: (a) calculating a damping factor, e.g., a damping ratio represented by ?, or a quality factor Q, where ??1/2Q, for a transient signal received, having been emitted from a resonator-type sensor element; (b) determining amplitude, A, of the transient signal; or (c) generating a frequency response dataset of interrelated points for the transient signal. A threshold comparison circuit is included for converting the transient signal received into a first and second digital waveform; the first digital waveform represents cycle crossings of the transient signal associated with a first threshold value, and the second digital waveform represents cycle crossings of the transient signal associated with a second threshold value. The transient signal may be converted, likewise, into third, and so on, digital waveforms, whereby the third digital waveform represents cycle crossings of the transient signal associated with a third threshold value.

Abstract: A device (1) for determining the qualify of a medium, particularly of a lubricant and/or cutting oil, includes a number of sensors (3, 4, 5, 6, 7) that emit electric output signals according to the respective sensor-specific input variables. One sensor is a temperature sensor (7) that emits an output signal, which is essentially only dependent on the temperature (T) of the medium and is essentially independent of, in particular, the quality of the medium. At least one other sensor (3, 4, 5, 6) emits an output signal that is dependent on both the quality of the medium as well as the temperature (T) of the medium. The sensors (3, 4, 5, 6, 7) are placed on a shared substrate (2) that can be immersed in the medium. An associated process also determines the quality of a medium.