Various embodiments include a method for monitoring the tank content of a storage tank comprising: metering a fluid from the tank into the exhaust gas tract, wherein the fluid has a concentration with respect to a reducing agent; acquiring a current concentration value for the reducing agent; calculating a change in concentration of the reducing agent on the basis of the current concentration value in comparison with a stored concentration value; determining a current operating state of the vehicle to identify an operating state in which refueling cannot be carried out; and carrying out a plausibility check of the calculated change in concentration if the calculated change in concentration exceeds a predetermined threshold value and the operating state is identified. The plausibility check includes acquiring the current tank filling level of the fluid.

A sensor assembly is provided for detecting a concentration of a fluid. The sensor assembly includes a sensing unit and a cover assembly. The sensing unit includes a transmitter configured to transmit a signal into a sensing volume and a receiver configured to receive the signal after the signal passes through a portion of the sensing volume. The cover assembly at least partially encloses the sensing volume and is substantially impermeable to a gas portion of the fluid. The cover assembly includes apertures defined therein which are permeable to the gas portion of the fluid. A first plurality of apertures are defined along a top surface of the cover assembly.

The present invention relates to a method and system for measuring characteristics of a multiphase flow from structural vibration signals. In this sense, the objectives of the invention are achieved by means of a method for measuring characteristics of a multiphase flow from structural vibration signals which comprises: obtaining, by means of acceleration sensors (V01, V02, T00) externally fixed to a pipeline, signals based on pipeline internal flow vibration; processing, by means of a processing device, the obtained signals; and determining a dispersion curve fitting coefficient to determine the void fraction of the mixture.

An analyzer determining/classifying aircraft air contaminants using a contaminant collector comprises a microporous medium, a bypass; a sensor generating frequency response when contaminant mass is added to/removed from the sensor, receiving contaminants desorbed from the medium; a first sample flow path, passing through the collector; a second sample flow path, bypassing the collector; a frequency measurement device, measuring response generated by the sensor as contaminant is added to and removed; a computer readable medium bearing a contaminant recognition program and calibration data; and, a processor executing the program, the program including a module classifying the contaminant and measuring response signal magnitudes, and a module using the data for comparison with magnitude of the response generated by the sensor to calculate contaminant concentration and determine a target value for contaminant type, and using measured response magnitudes to adjust first sample flow rates and/or flow durations based upon measured response magnitudes.

A light emitter device contains a heater structure configured to emit light if a predefined current flows through the heater structure. The heater structure is arranged at a heater carrier structure. The light emitter device contains an upper portion of a cavity located vertically between the heater carrier structure and a cover structure. The light emitter device contains a lower portion of the cavity located vertically between the heater carrier structure and at least a portion of a carrier substrate. The heater carrier structure contains a plurality of holes connecting the upper portion of the cavity and the lower portion of the cavity. A pressure within the cavity is less than 100 mbar.

The objective of the present invention is to measure gas concentration with a high degree of accuracy. A gas sensor is provided with: a sensor enclosure: an ultrasonic transducer provided at one end of the sensor enclosure; an ultrasonic wave reflecting surface which is provided at the other end of the sensor enclosure and which intersects an axial direction of the sensor enclosure; and a plurality of ventilation holes provided in a side wall of the sensor enclosure. The plurality of ventilation holes are provided at positions such that one side of the sensor enclosure cannot be seen from the other side thereof when viewed from a side surface side of the sensor enclosure, and each ventilation hole has a shape extending in the axial direction of the sensor enclosure.

Various exemplary embodiments relate to a device to measure carbon dioxide (CO.sub.2) levels, including a first oscillator group comprising a first sensor to measure air pressure, where the first sensor comprises a first sealed membrane, and where the first sealed membrane overlays a sealed first cavity; a second oscillator group including a second sensor to measure the resonance frequency of a second unsealed oscillating membrane, and where the second unsealed membrane overlays a second cavity in contact with the air outside of the second sensor; and a mixer accepting as input a first frequency measurement output from the first oscillator group and a second frequency measurement output from the second oscillator group, outputting the difference of the first frequency measurement and the second frequency measurement, and computing a carbon dioxide measurement based on the difference.

Embodiments of the present disclosure provide an apparatus for determining a characteristic of a fluid. The apparatus may include a device configured to determine a hydrodynamic pressure of the fluid. The apparatus may further include a sensor configured to determine a hydrostatic pressure of the fluid or at least one component of the fluid. The apparatus may also include a common substrate on which the sensor and the device configured to determine a hydrodynamic pressure of the fluid may be commonly arranged, and an ASIC (Application Specific Integrated Circuit) which may be electrically coupled with at least one of the device or the sensor. The ASIC may be at least partially embedded in the common substrate.

Disclosed are methods for determining and classifying aircraft air contaminants comprising one or more of: turbine engine oil, hydraulic fluid and deicing fluid using contaminant analyzers comprising a contaminant collector comprising a membrane and a heater vaporizing the contaminants; a gravimetric sensor generating a response when contaminant mass is added to or removed from the sensor, the sensor receiving contaminants desorbed from the heated membrane; a frequency measurement device, measuring the response generated by the sensor as the contaminant is added to and removed from the sensor; a computer readable medium bearing a contaminant recognition program and calibration data; a processor executing the program, the program including a module classifying contaminants by type, and a module using the data for comparison with magnitude of response generated by the sensor to calculate contaminant concentration; and, a pump, generating flow of air through the collector before and after the membrane is heated.

In an embodiment, a system includes a plurality of sensor devices contained in a plurality of wells contained in a well-plate assembly. The sensor devices are used in a plurality of oscillators. Each oscillator generates a frequency and a resistance based on a quality of living biological cells contained in a corresponding well. The quality may include, for example, surface coupled mass, density, viscosity, and/or viscoelasticity of the living biological cells. The system also includes logic for measuring a resonant frequency and motional resistance associated with each sensor device and logic for processing the measured resonant frequency and motional resistance. Moreover, the system includes logic for displaying one or more graphs showing one or more characteristics of the living biological cells contained in the wells.