Abstract: An apparatus and system for measuring and monitoring fouling parameters in a fluid are provided. The apparatus includes a conduit within a housing, wherein at least a portion of the conduit provides a carbon dioxide permeable membrane through which carbon dioxide in the fluid can permeate in use. A carbon dioxide sensor within the housing is configured to measure carbon dioxide levels at the sensor. The housing further includes a light source that irradiates a portion of the conduit and a light sensor that is configured to measure light transmitted through or reflected by the irradiated portion of the conduit to measure the amount of fouling material within the fluid and attached to the irradiated portion of the conduit in use.

Abstract: A method for characterizing a process fluid comprising applying electrical power to a first resistance temperature detector (RTD) in contact with a fluid to increase the temperature of the first RTD; allowing the first RTD to cool toward a fluid equilibrium temperature; analyzing the temperature decay profile of the first RTD over time to determine thermal characteristics; applying electrical power to a second RTD in contact with the fluid to increase the temperature of the second RTD; allowing the second RTD to cool toward the fluid equilibrium temperature; analyzing the temperature decay profile of the second RTD over time to determine thermal characteristics; comparing the thermal characteristics of the first and second RTD to determining one or more characteristics of the fluid based; and performing a corrective action. The first RTD has a first coating and the second RTD has a second coating different than the first coating.

Abstract: A method of operating a gas sensing device is described. The method includes receiving a signal indicative of a value of resistance of a gas sensing element, processing the signal received to compute a value of a gas concentration, performing a comparison of the value of gas concentration to a threshold, and, based on the outcome of a diagnosis procedure, setting the device to an alert signal issue state as a function of the outcome of the comparison. The diagnosis procedure includes computing a set of parameters indicative of the state of the gas sensor circuit, and classifying the gas sensor circuit in one of a first, a second and a third class based on the parameters.

Abstract: When starting of a fuel gas consuming device configured to consume a fuel gas is instructed, an electric power is supplied to a fuel gas sensor that has a predetermined unstable period until an accuracy of fuel gas detection reaches a predetermined level after having been supplied with electric power, supply of the fuel gas from a fuel gas supply device to the fuel gas consuming device is started by opening an electric valve that is electrically opened and shut off. When a signal from the fuel gas sensor exhibits behavior of approaching a predetermined determination threshold value before the unstable period has elapsed, the electric valve is shut off. When the signal from the fuel gas sensor is less than a predetermined determination value in a predetermined period after the electric valve has been shut off, the electric valve is opened.

Abstract: A combustible gas sensor for detecting an analyte gas includes a first element including a first electric heating element, a first support structure on the first electric heating element and a first catalyst supported on the first support structure and electronic circuitry in electrical connection with the first element. The electronic circuitry is configured to provide energy to the first element to heat the first element to at least a first temperature at which the first catalyst catalyzes combustion of the analyte gas and to determine if the analyte gas is present based on a response of the first element to being heated to at least the first temperature. The electronic circuitry is further configured to apply an interrogation pulse to the first element in which energy to the first element is increased or decreased to induce an associated response from the first element.

Abstract: An atomic oscillator includes a gas cell in which metal atoms are sealed, a heating unit that is driven by the supply of power and heats the gas cell, a power terminal, and a boosting circuit that boosts a voltage output from the power terminal and then is applied to the heating unit. The boosting circuit has a switching regulator function, and a switching frequency of the boosting circuit is equal to or higher than 10 kHz and equal to or lower than 10 MHz.

Abstract: The present invention provides methods for reducing the propagation of a flame to or from a refrigerant source and an ignition source in or adjacent to a cooling system, comprising positioning a metal mesh flame arrestor between said refrigerant source and said ignition source. The methods allow the use of flammable refrigerants with reduced risk of fire.

Abstract: Methods of, and apparatus for, storing and transporting a hazardous fluid, such as a combustible fuel, include methods and means, respectively, for: (a) treating the fluid to reduce its hazardous condition; (b) storing and/or transporting the treated fluid in such a manner that the risk of its hazardous condition remains reduced; (c) thereafter retreating the fluid to restore it to its original hazardous condition so that the fluid may be used in its restored condition. The hazardous fluid may be treated by adding a substance to, or removing a substance from, the fluid, or by changing the state of the fluid. For example, if the fluid is a fuel, it may be treated by cooling it to near or below its freezing temperature to reduce its combustibility, volatility, explosivity and/or ease of ignition.

Abstract: Provided is a gas sensor that needs no temperature sensor for detecting a temperature of a heater for preventing dew condensation. The gas sensor comprises a hydrogen sensor 1 including: an element housing 13 having a detection chamber 13a to which hydrogen is introduced; a detection element 31 arranged in the detection chamber 13a and detecting hydrogen; a heater 21 for heating the detection chamber 13a by heat generation via passing an electric current through the heater 21, a resistance value of the heater 21 being changed corresponding to a temperature of the detection chamber 13a; and a microcomputer 51 and a heater operation circuit 52 for controlling the heater 21. Herein, the microcomputer 51 controls a temperature of the detection chamber 13a by adjusting the electric current passing through the heater 21 based on the resistance value of the heater 21.

Abstract: A gas-sensing element configured to measure a concentration of a specific component of a gas is mounted to a first circuit board which includes a driving circuit configured to drive the gas-sensing element. A moisture-proof material is disposed over at least one side of the first circuit board disposed in a tubular gas-sensing element case fixed to a sensor case. A gas-sensing chamber is defined by the first circuit board and an inner tubular surface of the gas-sensing element case, and opens at an open end of the gas-sensing element case to receive the gas to be monitored. A second circuit board which includes a control circuit configured to control the gas-sensing element via the driving circuit is fixed to a sensor case, and disposed in a position separate from the gas-sensing chamber such that the second circuit board is kept out of contact with the gas to be monitored.

Abstract: A gas sensing device (nanosensor) includes a substrate with at least a pair of conductive electrodes spaced apart by a gap, and an electrochemically functionalized semiconductive nanomaterial bridging the gap between the electrodes to form a nanostructure network. The nanomaterial may be single-walled carbon nanotubes (SWNTs) functionalized by the deposition of nanoparticles selected from the group consisting of an elemental metal (e.g., gold or palladium), a doped polymer (e.g., camphor-sulfonic acid doped polyaniline), and a metal oxide (e.g. tin oxide). Depending on the nanoparticles employed in the functionalization, the nanosensor may be used to detect a selected gas, such as hydrogen, mercury vapor, hydrogen sulfide, nitrogen dioxide, methane, water vapor, and/or ammonia, in a gaseous environment.

Abstract: Methane gas in a ruminant exhalation may be oxidized to reduce the amount of methane gas output by the ruminant.

Abstract: A device dynamically detects particles of a fluid. The device can be miniaturized for detecting and selecting magnetized particles, particularly cells.

Abstract: A gas sensor is provided. The substrate of the gas sensor has a first surface, a second surface and a cavity. The cavity has an opening at the first surface. An insulating film is disposed on the first surface and covers the opening. A heating unit is embedded in the insulating film and located above the opening. An electrode pair is disposed on the insulating film and electrically separated from the heating unit. A buffer layer is disposed on the insulating film and located above the heating unit. The buffer layer is electrically connected to the electrode pair, and at least part of an orthogonal projection of the buffer layer on the first surface is located on the substrate next to the opening. The gas sensing layer is disposed on the buffer layer and has a nano-catalyst therein.

Abstract: An assembly and method for gas analysis. The assembly comprises a catalyst compartment for catalytically reacting a component of a gas sample, producing one or more gas species as products. A product compartment receives the gas species, and a sensing element within the compartment senses the amount of one or more of the gas species. This amount is compared to the amount of the same gas species present in a reference compartment containing a non-catalyzed gas sample, providing the amount of the gas species produced by catalysis. Using this value, the content of the gas component in the gas sample is calculated based upon the stoichiometry of the catalyzed reaction. In preferred embodiments, the gas for analysis is a process gas for fuel production, and the catalyst is a high temperature shift catalyst that catalyzes the reaction of carbon monoxide and water into hydrogen and carbon dioxide.

Abstract: A device for sensing a gas comprises a plastics housing (106, 107) moulded in situ around at least one portion of a conducting lead frame (100), the housing defining an enclosure (113) and being provided with means for enabling gas flow into the enclosure. A gas sensitive element (114) within the enclosure (113) is mounted to the conducting lead frame (100). The conducting lead frame (100) comprises connection leads which are accessible through, and at least partially encapsulated by, the wall of the housing.

Abstract: A microfabricated TID comprises a microhotplate and a thermionic source disposed on the microhotplate. The microfabricated TID can provide high sensitivity and selectivity to nitrogen- and phosphorous-containing compounds and other compounds containing electronegative function groups. The microfabricated TID can be microfabricated with semiconductor-based materials. The microfabricated TID can be combined with a microfabricated separation column and used in microanalytical system for the rapid on-site detection of pesticides, chemical warfare agents, explosives, pharmaceuticals, and other organic compounds that contain nitrogen or phosphorus.

Abstract: A gas detection apparatus A comprises a signal processing circuit 20, a Wheatstone bridge circuit 21, integrating circuits 22 and 23, a differential amplification circuit 24, a direct current power supply circuit 25, a heater voltage application circuit 26. The Wheatstone bridge circuit 21 is configured of parallel combination of series circuits: one composed of a catalytic combustion type gas sensor 1 and a load resistor R1, and the other composed of a resistor R2, a variable resistor VR1 and a resistor R3. The heater voltage application circuit 26 is configured to generate a pulsed heater voltage by switching a direct current voltage of the direct current power supply circuit 25 through a transistor TR1 for applying the pulsed heater voltage to the Wheatstone bridge circuit 21. The integrating circuit 22 integrates a voltage at a connection point between the gas sensor 1 and the load resistor R1.

Abstract: A circuit with at least one catalytic measuring element (1), in which the at least one catalytic measuring element (1) is connected to a supply voltage (5) without a protective resistor and without a thermal safety device arranged upstream. The circuit makes it possible to develop gas-measuring devices with catalytic measuring elements that are characterized by an especially low power consumption.

Abstract: A gas sensor which includes walls delimiting a gas detection chamber, and having an introduction port (or an inlet) through which an observed gas is introduced into the gas detection chamber, a measuring element disposed in the gas detection chamber and measuring concentration of a subject gas contained in the observed gas, and a heater constituting at least a portion of the walls, the portion facing the gas detection chamber.

Abstract: A gas sensor including: a gas detection element; a metal shell extending in an axial direction; and a metal cylinder extending in an axial direction, wherein a leading end portion of the metal cylinder surrounds a base end portion of the metal shell and is fixed to the metal shell via a circumferential welded portion. The metal shell includes: Fe in an amount equal to or more than 50.0 mass %; C in an amount of 0.02 mass % to 0.15 mass %; Cr in an amount of 11.5 mass % to 18.0 mass %; and Nb in an amount equal to or more than twice amount of C in mass %.

Abstract: In vitro electrochemical sensors that provide accurate and repeatable analysis of a sample of biological fluid are provided. Embodiments include sensors that include a sample chambers having overhangs extending therefrom.

Abstract: A low power consumption catalytic gas sensor includes three beads. A trigger bead, which is smaller than either a sensing on a compensating bead can be monitored for the presence of a combustible gas. Where gas has been sensed, the sensing and compensating beads can be energized to establish a gas concentration.

Abstract: The present invention relates to a molecular sensor for detecting the presence of a target analyte comprising a nitro-containing explosive molecule, the sensor comprising: a support substrate; a pair of electrodes comprising (i) a first electrode and (ii) a second electrode, wherein at least one of (i) and (ii) is at the substrate; an electron donor (ED) molecule capable of forming an electron donor-acceptor (EDA) complex with the nitro-containing explosive molecule; and wherein the ED molecule is disposed between the electrodes and is attached to each electrode by an alligator clip comprising a pendant group, thereby forming a nanojunction between the electrodes; a detection means operably connected to the pair of electrodes, the detection means capable of detecting a change in the electrical resistance or in the capacitance of the sensor when the ED molecule forms an EDA complex with the explosive molecule, the sensor thereby detecting the presence of the explosive molecule.

Abstract: An assembly and method for gas analysis. The assembly comprises a catalyst compartment for catalytically reacting a component of a gas sample, producing one or more gas species as products. A product compartment receives the gas species, and a sensing element within the compartment senses the amount of one or more of the gas species. This amount is compared to the amount of the same gas species present in a reference compartment containing a non-catalyzed gas sample, providing the amount of the gas species produced by catalysis. Using this value, the content of the gas component in the gas sample is calculated based upon the stoichiometry of the catalyzed reaction. In preferred embodiments, the gas for analysis is a process gas for fuel production, and the catalyst is a high temperature shift catalyst that catalyzes the reaction of carbon monoxide and water into hydrogen and carbon dioxide.

Abstract: Detecting air ingredients is obtained, a heater and gas sensitive acting layers are arranged on a substrate, which are connectable to an analyzing unit. Electrical resistances of n acting layers are connected in series; heater is a temperature sensor connected in parallel with this series connection, electrical resistance of heater is smaller than the sum of electrical resistances of acting layers and resistances are connected with a total of n+1 electrical terminals via electrodes so that heater is connected with two terminals and n?1 other terminals are connected with a respective junction that interconnects two acting layers. Heater is intermittently heated so that a predefined constant temperature of acting layers is achieved, temperature of acting layers is acquired by determining electrical resistance of heater; voltages in the series connection of acting layers are analyzed and a concentration of gases are determined from electrical resistances of acting layers.

Abstract: The present invention relates to methods of making compositions for sensor films used for detecting chemical analytes within sensors, such as polymer-absorption chemiresistors (i.e., conductometric sensors). The sensor films have reduced cross-sensitivity to temperature, while maintaining sensitivity to the chemical analytes. The sensor matrix includes components that are associated with a first temperature coefficient of resistance, such as a polymer resin and/or a first conductive particle. The sensor matrix further comprises a second species, preferably a conductive particle, which has a second temperature coefficient of resistance that is opposite to the first temperature coefficient of resistance. The second species has an opposite influence on a resistance response of the sensor from the first species. In this manner, the sensor matrix exhibits a minimized response in resistance to any changes in temperature.

Abstract: An electrochemical sensor for corrosive gases that contains at least two electrodes is described. The presence of a target corrosive gas results in the formation of metal ions that can be reduced at an electrode producing an electrical current that depends on the instantaneous corrosive gas concentration and deposition of the metal on the electrode. Extension of this deposit to a second electrode through further deposition will result in a short circuit, the longer the time to the short circuit, the lower the cumulative corrosive gas concentration.

Abstract: A gas detection apparatus A comprises a signal processing circuit 20, a Wheatstone bridge circuit 21, integrating circuits 22 and 23, a differential amplification circuit 24, a direct current power supply circuit 25, a heater voltage application circuit 26. The Wheatstone bridge circuit 21 is configured of parallel combination of series circuits: one composed of a catalytic combustion type gas sensor 1 and a load resistor R1, and the other composed of a resistor R2, a variable resistor VR1 and a resistor R3. The heater voltage application circuit 26 is configured to generate a pulsed heater voltage by switching a direct current voltage of the direct current power supply circuit 25 through a transistor TR1 for applying the pulsed heater voltage to the Wheatstone bridge circuit 21. The integrating circuit 22 integrates a voltage at a connection point between the gas sensor 1 and the load resistor R1.

Abstract: A vapor analysis system comprising a vapor analyzer capable of collecting and analyzing a vapor sample for detection of a compound that may be contained within the vapor sample. A controller is coupled to the vapor analyzer. The controller is programmed to produce an indicator signal indicative of a relative concentration of the compound detected by the vapor analyzer within the vapor sample. A sample probe includes a housing containing a vapor channel through which the vapor sample is collected, and a vapor cable couples the sample probe to the vapor analyzer to allow collection and channeling of the vapor sample to the vapor analyzer. A multi-dimensional user indicator is disposed on the housing of the sample probe receives and operates in response to the indicator signal to indicate the relative concentration of the compound detected within the vapor sample for presentation via a multi-directional stimulus to a user of the vapor analysis system.

Abstract: A microelectro-mechanical chemical sensor includes an active cantilever beam having a chemically selective material layer disposed thereon and at least one, preferably two, resistors with the resistance corresponding to the cantilever beam deflection. The sensor also has at least two, and preferably four, auxiliary cantilever beams adjacent to the active cantilever and attached to the same substrate, each having a piezoresistor disposed thereon. The piezoresistors are elements of a Wheatstone bridge, and the Wheatstone bridge output indicates the amount of a predetermined target chemical sorbed by the chemically selective material layer. The sensor is electrostatically actuated in order to monitor the resonant frequency.

Abstract: A hydrogen sensor 25 has a fitting base plate 29 in which a gas-sensing chamber 34 is formed, a specimen gas intake 35 formed on said fitting base plate 29, opening toward an exit passage 24 and introducing hydrogen gas into the gas-sensing chamber 34, a gas-sensing element 39 held in the gas-sensing chamber 34 and adapted to sense hydrogen gas, and a water-repelling filter 44 covering the specimen gas intake 35.

Abstract: In order to provide a step capable of reliably detecting a CO concentration in a reformed gas at low cost and a hydrogen purifier capable of fully exerting a function of a CO purifying catalyst, a gas concentration detector comprising a reaction chamber which has a catalyst layer and a gas temperature detector and capable of detecting the concentration of carbon monoxide in the gas by means of a signal of the temperature detector referring to a reformed gas passing along through the reaction chamber.

Abstract: New sensors and methods for qualitative and quantitative analysis of multiple gaseous substances simultaneously with both high selectivity and high sensitivity are provided. The new sensors rely on a characteristic difference in energy between the interaction of a particular substance with a catalyst coated heat transfer device (HTD) and a non-catalyst coated (or one coated with a different catalyst) reference HTD. Molecular detection is achieved by an exothermic or endothermic chemical or physical reaction between the catalytic surface of the sensor and the molecule, tending to induce a temperature change of the sensor. Both high temperature and non-destructive low temperature detection are possible. The magnitude and rate of endothermic or exothermic heat transfer from a specific molecule-catalyst interaction is related to molecular concentration.

Abstract: A method of determining bias in a measurement of a constituent concentration level in a sample gas is provided. The method comprises establishing a sample gas flow from an emission stream into a sample gas line of an emissions monitoring system. The method further comprises removing water from the sample gas flow and cooling the sample gas flow to a temperature below about 41° F. to produce a cooled, dried sample gas flow. The constituent concentration level is then determined for the cooled, dried sample gas flow. The method further comprises introducing a span gas having a known span gas constituent concentration level into the sample gas flow to form a combined sample and span gas flow, the span gas being introduced at a desired span gas flow rate. The method still further comprises removing water from the combined sample and span gas and cooling the combined sample and span gas to a temperature below about 41° F. to produce a cooled, dried, combined sample and span gas flow.

Abstract: A device and method for quantifying an impurity in an input gas stream. The device and method employ a catalyst to convert the impurity to a detectable species in an output gas stream, and the concentration of the detectable species is then measured by means of a detector.

Abstract: An air quality monitor having multiple sensors deployed in an electric circuit returns a single sign indication of atmospheric impurity regardless of whether the impurity gas is of the oxidizing or reducing type. Each sensor employs a gas sensitive material that exhibits a response in the form of a change in electrical resistance of the material in the presence of a gas and that exhibits a negligible response to changes in the moisture content of the atmosphere. A powder is dried and calcined and the result is ground into a fine powder and pressed into a desired shape to make the gas sensitive material. Adding a binder during the pressing and firing the shaped powder results in a gas sensitive material with porosity. Gas is flowed to the gas sensitive material and the resulting change in resistance is measured and returned as a single sign indication of atmospheric impurity.

Abstract: Provided is a gas molecule sensor, characterized in that the sensing element is a polycrystalline tin oxide film having a thickness less than 1 ?m. The sensing element is produced by electrolytic deposit of a tin film on an insulating support in an electromechanical cell, where the anode is comprised of tin and the cathode is a conductive film applied on the surface of the insulating support at one of its ends, the two electrodes being separated by an electrolyte comprised of a tin salt solution, and by passing a constant current through said cell. The deposit step is followed by an oxidizing step.

Abstract: A powder filler is stuffed in a filler space defined between a housing and a gas sensing element so as to airtightly seal a clearance between the housing and the gas sensing element. The powder filler contains grains whose diameter is in a range from 80 ?m to 5,000 ?m when measured before being stuffed into the filler space. A weight percentage of the grains having the diameter of 80 ?m to 5,000 ?m is equal to or larger than 80% with respect to an overall weight of the powder filler.

Abstract: Of a gas detector 100, a chamber 105 formed between a center cover 150 and a cover 160 is a part of an air flow channel AF. A first shielding plate 165 is provided in the chamber 105. Water droplets that have entered the chamber from a chamber entrance 103 with air hit and adhere to an entrance-opposed surface 165E of the first shielding plate 165. The water thus adhering to the surface is pushed by the air flowing along the entrance-opposed surface 165E and by gravity, to thereby advance downward. The water then drips downward and is accumulated on a bottom wall surface 105WD which serves as an upper surface of a bottom wall section 161WD. The water is pushed by the flow of air, to thereby advance toward a chamber exit 104. The water is then drained downward from the chamber exit 104.

Abstract: A lightweight and portable analyzer is provided. At least one component of the analyzer is made from a lightweight material, such as ABS. A manifold can have a plate and gas passages ultrasonically welded together. By having at least one component made from a lightweight material, the analyzer is lighter.

Abstract: A hydrocarbon sensor and collector. An element that is capable of absorbing and releasing hydrocarbons is positioned in the air intake system of a vehicle, upstream from the engine and wholly in the airflow. The element has a plurality of chambers defined in it that allow air to pass through the element. The hydrocarbon sensor and collector also includes a means for detecting the level of hydrocarbons absorbed by the element.

Abstract: A poison resistant combustible gas sensing element, a method for its production and a method for determining poisoning of the element. The element includes an electric heating element, an inner layer coated on the electric heating element and containing a precious metal catalyst supported on a porous oxide, the precious metal catalyst catalyzing combustion of a combustible gas to be detected by the element, and an outer layer overlaying the first layer, and containing a catalytic compound capable of trapping gases which poison the precious metal catalyst, the catalytic compound being supported on a porous oxide.

Abstract: A poison resistant combustible gas sensing element, a method for its production and a method for determining poisoning of the element. The element includes an electric heating element, an inner layer coated on the electric heating element and containing a precious metal catalyst supported on a porous oxide, the precious metal catalyst catalyzing combustion of a combustible gas to be detected by the element, and an outer layer overlaying the first layer, and containing a catalytic compound capable of trapping gases which poison the precious metal catalyst, the catalytic compound being supported on a porous oxide.

Abstract: Disclosed herein is a method and apparatus for analyzing, sensing and measuring the concentrations of various gases, including NOx, hydrocarbons, carbon monoxide and oxygen, in a multi-component gas system using chemical sensors and chemical sensor arrays. The sensors and sensor arrays use chemo/electro-active materials to analyze and detect the presence of gases.

Abstract: A method and apparatus for sensing a flammable vapor are described herein. Initially, a first thermal conductivity of a vapor at a first temperature and a second thermal conductivity of the vapor at a second temperature can be determined. Thereafter, a ratio of the first thermal conductivity signal to that of the second thermal conductivity can be calculated to obtain a primary “vapor” signal. The “vapor” ratio can then be compared to an “air” ratio of air without the vapor at the first temperature and the second temperature to obtain a secondary signal thereof. Such a secondary signal can then be compared to an alarm set-point value to thereby determine whether the vapor comprises a flammable vapor and a risk-reducing action thereof be taken.

Abstract: Intended for application on ducts through which flow a fluid at a high temperature, and particularly at a high pressure, comprising two bodies (4) and (8) which axially screw onto each other, one body (4) provided with a threaded neck (5) for attachment to the orifice of duct wall (3), which body (4) houses within it sensor element (2) of the probe which is thus placed inside the duct, with second body (8) screwed onto first body (4) and exerting on sensor element (2) the pressure required to secure it in its housing, with second body (8) further provided with an axial orifice through which passes a metallic tube (9) open to the exterior and which is provided with a metallic washer (10), soldered to said tube (9), which is separated from second body (8) by an electrically insulating washer (12).

Abstract: A combustible gas sensor includes an active element in electrical connection with a measurement circuit. The measurement circuit includes a thermistor network to compensate for the effect of changes in ambient temperature to the resistance of the active element. Another combustible gas sensor includes an active element having a geometric surface area no greater than approximately 0.5 mm2 in electrical connection with a measurement circuit. The measurement circuit includes a compensator that compensates for the effect of changes in ambient temperature to the resistance of the active element without compensating for heat lost by thermal conduction from the active element.

Abstract: A sensor for detecting a target matter includes a chemical sensitive layer that is operable to react when exposed to the target matter and a piezoresistive material coupled to the chemical sensitive layer. The chemical sensitive layer is configured such that the reaction of the target matter with the chemical sensitive layer creates an interfacial tension at the interface of the chemical sensitive layer and the piezoresistive material that changes the electrical resistance of the piezoresistive material. However, the chemical sensitive layer is configured such that the reaction of the target matter with the chemical sensitive layer does not affect the bulk properties of the chemical sensitive layer enough to change the electrical resistance of the piezoresistive material. The sensor also includes an electrical circuit coupled to the piezoresistive material that is operable to detect the change in the electrical resistance of the piezoresistive material due to the interfacial tension.

Abstract: The measuring sensor, particularly a lambda probe, has a ceramic sensor member retained at a high temperature during measuring operation. It is shielded from water droplets, carried along in the gas to be analyzed, by a heated protective housing, permeable for the gas to be analyzed, by which water droplets carried along in the direction of the sensor member are evaporated before reaching the sensor member. In this way, the water droplets are unable to cause any shock-like temperature drops at spots on the surface of the sensor member or material flaking.