A device for determining properties of a medium, comprising a carrier which can be brought in contact with the medium; at least one transmitter arranged on the carrier for exciting acoustic waves in the carrier; at least one receiver arranged on the carrier for receiving acoustic waves which originate from waves excited in the carrier by means of the transmitter; and first and second material regions arranged on the carrier, wherein the second material region absorbs sound waves with the frequency of the acoustic waves excited in the carrier more strongly than the first material region. The carrier has a first surface with which it is to be brought in con-tact with the medium and a second surface which faces away from the first surface, wherein the transmitter as well as the first and the second material region are arranged on the second surface.

An oxygen concentrator may rely on a pressure swing adsorption process to produce an oxygen enriched gas stream from canisters filled with granules capable of separation of oxygen from an air stream. The adsorption process uses a cyclical pressurization and venting of the canisters to generate an oxygen enriched gas stream. Coupling an oxygen concentration sensor to the generated oxygen enriched gas stream may allow monitoring of the purity of the produced gas.

An oxygen concentrator may rely on a pressure swing adsorption process to produce an oxygen enriched gas stream from canisters filled with granules capable of separation of oxygen from an air stream. The adsorption process uses a cyclical pressurization and venting of the canisters to generate an oxygen enriched gas stream. The oxygen concentrator system may operate in multiple modes, automatically determined or selected by the user, to take into account the different activity levels of the user.

A surface acoustic wave sensor system for determining environmental conditions on a substrate. The system comprises an interrogator for producing an RF interrogating signal transmitted by an antenna to an interdigital transducer mounted on the substrate for producing an incident surface acoustic wave responsive to the interrogating signal. A plurality of reflector arrays mounted on the substrate produce a like plurality of reflected surface acoustic waves; a spacing between adjacent ones of the plurality of reflector arrays comprising a non-uniform distance. The plurality of reflected surface acoustic waves are responsive to the environmental condition and exhibit a characteristic from which the environmental condition can be determined by a processing component.

A computer system has processing circuitry configured to receive sensing data from at least one sensor arranged to detect sound waves emitted from electrical energy storage cells of an electrical energy storage system, the sensing data indicating at least one characteristic of the sound waves, apply an algorithm configured to predict a thermal runaway event by analyzing the sensing data, provide a message if the outcome of the analysis is that a thermal runaway is predicted.

The present invention relates to system for measuring pressure and temperature based on change in the characteristic properties of a medium for ultrasound under the effect of pressure and temperature. The invention is based on two waveguides where geometry is adapted to the medium's characteristic properties for ultrasound such that only planar pressure waves are generated in the waveguides. The first of the waveguides is arranged for measuring temperature due to thermal expansion of the medium, where the medium is pressure-compensated by means of an internal compensator to prevent thermal pressure accumulation, and where measuring temperature is based on the medium's specific known characteristic data for ultrasound under the effect of temperature under constant pressure. The second waveguide is arranged for measuring pressure, based on waveguide and the medium's known characteristic properties for thermal expansion and pressure, and where the thermal effect is corrected analytically based on measurement of temperature in the first channel. The physical principle of the invention is based on the properties of a medium (oil) where the stability for high temperature and pressure is crucial for long-term properties. Long-term properties of ultrasound sensors are not physically linked to the medium's properties, such that change in characteristic properties of ultrasound sensors does not impair the accuracy of the medium unless the function of the ultrasound sensors ceases. The physical principle of the invention allows an arrangement where ultrasound sensors can be separated from measuring channels by a pressure barrier, such that the integrity of the pressure barrier is not broken.

Systems and methods of determining settlement characteristics of a drilling mud are disclosed. Conditions under which heavier elements of the drilling mud settle under the influence of gravity can be determined. Samples of drilling mud can be placed in testing cells, and ultrasonic test pulses can be transmitted through the samples. Responses to the test pulses can be detected and compared to other responses detected at different vertical positions within the testing cell. Settlement can be detected when the responses from different vertical positions are generally dissimilar. An environmental temperature of the testing cell can be changed over a testing time interval, and a settlement temperature can be determined by detecting a divergence in the responses from different vertical positions.

An environmental condition may be measured with a sensor (10) including a wire (20) having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone (200, 210) may be used to couple ultrasonic energy between a waveguide wire (202, 212) and a transducer (204, 214).

An environmental parameter sensor for a mobile device is described comprising a first acoustic transducer; a second acoustic transducer arranged at a predetermined distance from the first acoustic transducer; a controller coupled to the first acoustic transducer and the second acoustic transducer; wherein the controller is configured to determine at least one of a time-of-flight value and an attenuation value of an acoustic signal between the first acoustic transducer and the second acoustic transducer and to determine at least one environmental parameter from the at least one of the time-of-flight value and the attenuation value The environmental parameter sensor may determine environmental parameters such as temperature, wind speed, and humidity from acoustic measurements.

A method for calibrating a temperature measuring unit based on ultrasound measurement includes: establishing an empirical functional relationship between the medium temperature of a medium to be measured and the velocity of sound of a measurement signal passing through the medium to be measured; capturing at least the velocity of sound of the measurement signal, the temperature measured by means of a temperature sensor, and the time variation of the sensor temperature at at least two measuring points, wherein the at least two measuring points have a different medium temperature; determining the medium temperature from the measured temperature, taking into account the time variation of the sensor temperature, so that at least two pairs of values and exist; running a compensating curve through the pairs of values which corresponds to the empirical functional relationship; and storing the functional relationship.