Abstract: The presently-disclosed subject matter provides sensors and methods for detecting hydrogen by determining the conductivity of a chemiresistant film upon exposure to hydrogen, including for example chemiresistant films comprised of alkylamine-, alkylthiolate-, and/or surfactant-coated metal alloy nanoparticles.

Abstract: Described are CO sensors, methods for making the CO sensors, and methods for using the CO sensors. An exemplary CO sensor includes a ruthenium oxide present in a form having one or more surfaces, a pair of conductive electrodes operatively connected to a surface of the ruthenium oxide, and an electrical device operatively connected to the pair of conductive electrodes. The gas mixture contacts at least one surface of the ruthenium oxide during operation of the sensor and the electrical device applies a constant potential (or current) and measures a current (or potential) between the pair of conductive electrodes, from which a resistance can be derived as the gas mixture contacts at least one surface of the ruthenium oxide. The ruthenium oxide may have varying levels of hydration. Furthermore, the sensor operates at a temperature range of from about 25° C. to about 300° C.

Abstract: Compositions for sensor films used for detecting chemical analytes within sensors, such as polymer-absorption chemiresistors (i.e., conductometric sensors) are provided. Robust sensor film compositions that have low resistance, high conductivity, and greater temperature stability and sensitivity to chemical analytes are provided, as well as methods of making these sensor films. Such sensor film compositions include a matrix having a polymer resin and a plurality of conductive particles comprising an axial-geometry conductive particle. Exemplary axial-geometry conductive particles comprise graphene, such as a carbon nanotube. Blends of conductive particles are also contemplated, including blends of axial-geometry conductive particles, such as carbon nanotubes, and carbon black.

Abstract: An oxygen sensor device and method for a motor vehicle having an electrode within an outer shell for measuring oxygen in exhaust gas exiting the vehicle. A communication device, powered by a capacitor, wirelessly transmits the measured amount of oxygen from the electrode to a powertrain control module. Vibration transmitting from the motor vehicle shakes a magnet, wound inside a coil, for generating the electrical current used by the capacitor.

Abstract: A chemical sensor and a system and method for sensing a chemical species. The chemical sensor includes a plurality of nanofibers whose electrical impedance varies upon exposure to the chemical species, a substrate supporting and electrically isolating the fibers, and a set of electrodes connected to the plurality of fibers at spatially separated points to permit the electrical impedance of the plurality of fibers to be measured. The system includes the chemical sensor, an impedance measuring device coupled to the electrodes and configured to determine an electrical impedance of the plurality of fibers, and an analyzer configured to identify the chemical species based on a change in the electrical impedance. The method measures at least one change in an electrical impedance between spatially separated electrodes connected to a plurality of fibers upon exposure of the fibers to the chemical species, and identifies the chemical species based on the measured change in the electrical impedance.

Abstract: Disclosed herein is a method and apparatus for analyzing, sensing and measuring information related to 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: Compositions for sensor films used for detecting chemical analytes within sensors, such as polymer-absorption chemiresistors (i.e., conductometric sensors) are provided. Robust sensor film compositions that have low resistance, high conductivity, and greater temperature stability and sensitivity to chemical analytes are provided, as well as methods of making these sensor films. Such sensor film compositions include a matrix having a polymer resin and a plurality of conductive particles comprising an axial-geometry conductive particle. Exemplary axial-geometry conductive particles comprise graphene, such as a carbon nanotube. Blends of conductive particles are also contemplated, including blends of axial-geometry conductive particles, such as carbon nanotubes, and carbon black.

Abstract: A gas analyzer apparatus includes a device or platform for supporting a predetermined quantity of a reagent capable of reacting with a predetermined gas to cause a detectable change in a characteristic of the reagent, a reservoir adapted to retain the reagent, a dispenser for dispensing a controlled quantity of the reagent from the reservoir to a predetermined position on the device for supporting the predetermined quantity of the reagent, and a detector that detects the presence of the predetermined gas upon the predetermined gas and the controlled quantity of reagent reacting to cause a detectable change in a characteristic of the reagent detectable by the detector, the detector adapted to detect a change in the controlled quantity of the reagent by detecting the change in the characteristic through the predetermined quantity of the reagent.

Abstract: A chemical vapor sensor includes an elastomeric material layer, a first stratum of electrically conducting particles bonded chemically to the surface of the elastomeric layer, and a second stratum of nonconducting or semiconducting particles adhering to the first stratum of particles primarily through nonchemical particle-to-particle attractive forces.

Abstract: A sensor for detecting and differentiating chemical analytes includes a microscale body having a first end and a second end and a surface between the ends for adsorbing a chemical analyte. The surface includes at least one conductive heating track for heating the chemical analyte and also a conductive response track, which is electrically isolated from the heating track, for producing a thermal response signal from the chemical analyte. The heating track is electrically connected with a voltage source and the response track is electrically connected with a signal recorder. The microscale body is restrained at the first end and the second end and is substantially isolated from its surroundings therebetween, thus having a bridge configuration.

Abstract: Among other things, from a wireless device, a command is transmitted to wearable monitors within range of the wireless device to update their states to a non disinfected state of the hands of users of the wearable monitors.

Abstract: An array of sensor elements is formed by the incorporation of sensing materials into porous structures, creating sensing systems with extremely large surface areas with sensing molecules attached to mimic the large number of cilia of an olfactory system. In each sensor element, the sensing material or molecules are attached to spacer molecules or groups, which are attached to linker molecules or groups, which are attached to the porous substrate material. More specifically, a porphyrin doped aerogel material is used. The porphyrin sensing material is attached to the aerogel throughout its high surface area pore space. The porphyrin is covalently bonded to the silica network of the aerogel with a triethoxysilyl group linker that covalently attaches to the aerogel, and an alkyl group spacer.

Abstract: Provided are mixed ligand metal nanoparticle chemical sensors in which metal nanoparticles are encapsulated by at least two kinds of different molecule ligands having a relatively low conductivity and various composition ratios, and a chemical sensor array in which a film of the metal nanoparticle sensor is formed on the substrate. The metal nanoparticle sensor using the mixed ligand improves sensitivity and reaction speed with respect to an analyte, and selectivity with respect to various analytes, and a kind and a composition of a ligand of the mixed ligand constituting the metal nanoparticle sensor are adjusted to allow the high sensitivity nanoparticle sensor to be applied to the sensor array technology, thereby enabling a design of sensor properties as well as systematic access to a configuration of the sensor array the most efficient for the analytes.

Abstract: Described are CO sensors, methods for making the CO sensors, and methods for using the CO sensors. An exemplary CO sensor includes a ruthenium oxide present in a form having one or more surfaces, a pair of conductive electrodes operatively connected to a surface of the ruthenium oxide, and an electrical device operatively connected to the pair of conductive electrodes. The gas mixture contacts at least one surface of the ruthenium oxide during operation of the sensor and the electrical device applies a constant potential (or current) and measures a current (or potential) between the pair of conductive electrodes, from which a resistance can be derived as the gas mixture contacts at least one surface of the ruthenium oxide. The ruthenium oxide may have varying levels of hydration. Furthermore, the sensor operates at a temperature range of from about 25° C. to about 300° C.

Abstract: An apparatus for monitoring ammonia in gaseous streams, particularly in flue gas streams. The apparatus is transportable but can be permanently installed. The flue gas can be monitored in real time.

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: An apparatus and methods for monitoring the status of a cell that consumes oxygen. In one embodiment of the present invention, the method includes the steps of confining the cell in a sensing volume, measuring dynamically intracellular or extracellular signaling of the cell, and determining the status of the cell from the measured intracellular or extracellular signaling of the cell.

Abstract: A sensor for detecting and differentiating chemical analytes includes a microscale body having a first end and a second end and a surface between the ends for adsorbing a chemical analyte. The surface includes at least one conductive heating track for heating the chemical analyte and also a conductive response track, which is electrically isolated from the heating track, for producing a thermal response signal from the chemical analyte. The heating track is electrically connected with a voltage source and the response track is electrically connected with a signal recorder. The microscale body is restrained at the first end and the second end and is substantially isolated from its surroundings therebetween, thus having a bridge configuration.

Abstract: An automated analyzer for performing multiple diagnostic assays simultaneously includes multiple stations, or modules, in which discrete aspects of the assay are performed on fluid samples contained in reaction receptacles. The analyzer includes stations for automatically preparing a specimen sample, incubating the sample at prescribed temperatures for prescribed periods, preforming an analyte isolation procedure, and ascertaining the presence of a target analyte. An automated receptacle transporting system moves the reaction receptacles from one station to the next.

Abstract: A carbon dioxide sensor and a method of detecting carbon dioxide using the sensor are provided, the sensor includes a closed chamber having as a wall portion thereof a substantially watertight, carbon dioxide-permeable membrane, two electrodes disposed in the chamber, and a film of substantially electrolyte-free liquid disposed in the chamber capable of simultaneously contacting the membrane and both of the electrodes.

Abstract: An electronic system for selectively detecting and identifying a plurality of chemical species, which comprises an array of nanostructure sensing devices, is disclosed. Within the array, there are at least two different selectivities for sensing among the nanostructure sensing devices. Methods for fabricating the electronic system are also disclosed. The methods involve modifying nanostructures within the devices to have different selectivity for sensing chemical species. Modification can involve chemical, electrochemical, and self-limiting point defect reactions. Reactants for these reactions can be supplied using a bath method or a chemical jet method. Methods for using the arrays of nanostructure sensing devices to detect and identify a plurality of chemical species are also provided.

Abstract: An alcohol sensor having gas-sensitive layers made of polymers or inorganic oxides wherein a signal is read out by means of work function change which is produced in the form of a field-effect transistor.

Abstract: Methods for forming hydrogen sensing materials include forming a palladium alloy thin film having less than about 83 atomic percent of palladium, and annealing the palladium alloy thin film to relieve residual stress and increase atomic intermixing of the nanorystaline lattice, while maintaining a grain size close to the grain size of the nonannealed palladium alloy thin film. For example, the sensing material may include a palladium-gold alloy thin film having about 60 atomic percent of palladium and about 40 atomic percent of gold. The palladium-gold alloy thin film is then annealed at a temperature of about 200 degrees Celsius for 1 hour. Methods for detecting hydrogen containing gas in which the hydrogen sensing material is maintained in a single phase when exposed to the hydrogen containing gas, and optical hydrogen sensors are also disclosed.

Abstract: The present invention provides a gas detection method and detection apparatus that provide better sensitivity and faster recovery after response than conventional gas detection methods and apparatus, by improving on these conventional methods and apparatus. The present invention is a gas detection method, in which the target gas is detected while oxygen is supplied to a sensor element 11a of a metal oxide-type gas sensor 11, wherein the target gas is detected while water vapor is supplied to the sensor element 11a, and is also a gas detection apparatus equipped with an oxygen supply means 14 for supplying oxygen to a sensor element 11a of a metal oxide-type gas sensor 11, said gas detection apparatus being provided with a water vapor supply means 15 for supplying water vapor to the sensor element 11a.

Abstract: Carbon nanotube devices are manipulated in a manner that is useful for a variety of implementations. According to an example embodiment of the present invention, light (632) is used to photodesorb molecules from a carbon nanotube (620).

Abstract: A mixed potential sensor device and methods for measuring total ammonia (NH3) concentration in a gas is provided. The gas is first partitioned into two streams directed into two sensing chambers. Each gas stream is conditioned by a specific catalyst system. In one chamber, in some instances at a temperature of at least about 600° C., the gas is treated such that almost all of the ammonia is converted to NOx, and a steady state equilibrium concentration of NO to NO2 is established. In the second chamber, the gas is treated with a catalyst at a lower temperature, preferably less than 450° C. such that most of the ammonia is converted to nitrogen (N2) and steam (H2O). Each gas is passed over a sensing electrode in a mixed potential sensor system that is sensitive to NOx. The difference in the readings of the two gas sensors can provide a measurement of total NH3 concentration in the exhaust gas. The catalyst system also functions to oxidize any unburned hydrocarbons such as CH4, CO, etc.

Abstract: A breath alcohol detection device includes a one-piece multi-passage block with attached sensors, a valve and a fuel cell. The cell accurately determines the BrAC of a prospective vehicle operator. In the event the BrAC is less than the legal maximum for a territory, the device unlocks an ignition interlock to permit starting of the engine and operation of the vehicle.

Abstract: A proton conductor gas sensor whose durability at high temperature is enhanced by using gel not converted to sol even at high temperature in a water reservoir. Fine particles of silica are gelled by adding water thereto and agitating the mixture under shear force. The thus obtained gel (34) is placed in a water reservoir of proton conductor gas sensor (2) and fed through steam introduction port (30) to MEA (10).

Abstract: A method for investigating a target environment to determine whether or in what amount a chemical species may be present therein, which comprises: (a) exposing to said environment an article of manufacture comprising a multiplicity of particles in close-packed orientation, said particles having a core of conductive metal or conductive metal alloy and deposited thereon a ligand which is capable of interacting with said species such that a property of said multiplicity of particles is altered; (b) subjecting said multiplicity of particles to conditions sufficient for said property to be exhibited; and (c) monitoring said property to determine whether there is, or the amount of, any change as an indication of whether, or in what amount, said species is present; a multiplicity of particles suitable for use in such method; and equipment suitable for implementing the method.

Abstract: In an ammonia sensor (1), lead portions (7) and (9) are provided on an insulating substrate (5); a pair of comb-shaped electrodes (11) and (13) are connected to the lead portions (7) and (9), respectively; a sensitive layer (15) is provided on the comb-shaped electrodes (11) and (13); and a protective layer (17) is provided on the sensitive layer (15). Particularly, the sensitive layer (15) is formed of a gas-sensitive raw material predominantly containing ZrO2 and containing at least W in an amount of 2 to 40 wt. % as reduced to WO3.

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: An analytical system is provided for determining nitrogen monoxide, nitrogen dioxide and ozone concentrations in air samples. An ultraviolet light source 4 is used to alter the equilibrium between nitrogen dioxide and oxygen on the one hand and nitrogen monoxide and ozone on the other. Dynamic measurement of ozone concentration with time while ultraviolet irradiation is pulsed enables each gas concentration to be calculated without requiring input gases to be scrubbed. An aApparatus 101 is further provided to provide a controlled flow of gas to a sensor 103 attached to a high altitude balloon while sheltering it from the elements and allowing for affects of temperature, said apparatus comprising a shield 104 and a gas conducting means which uses the venturi effect to control air flow or has a hole to allow water to drain without affecting air flow past the sensor.

Abstract: A simultaneous multianalyte electrochemical assay includes a cell which has a surface and the surface includes analyte binding sites i.e., antibodies or antigens on a solid phase at distinct separate locations. Separate working electrodes are located within proximity to these separate locations. Enzyme labeled antibodies or antigens depending on the assay format are added and the enzyme reaction product measured, by simultaneous amperometric measurement with the independent electrode in each area. The electrodes are spatially separated from adjacent analytes so that a measurement can be taken before cross-interference due to diffusion of product from adjacent analyte areas.

Abstract: A protective coating for a surface comprising a layer permeable to hydrogen, said coating being deposited on a catalyst layer; wherein the catalytic activity of the catalyst layer is preserved.

Abstract: A system for quickly and automatically extracting and analysing residual solvents is realised for operating directly in the premises where the packing materials are being manufactured, printed and/or laminated. The system provides for a single unit equipped with a display and a keyboard, and comprises an extraction (desorption) chamber (1), an analysis chamber with valves and separating columns, a detection system (17), and a data processing system (19). The extracting or desorption chamber comprises a desorption cell (1) for receiving a vial (36; 37) containing said sample, and means are provided to keep the inside of said cell (1) at a pressure higher that that of the surrounding environment until a new sample has been introduced into the cell, thus accomplishing a “washing” of cell for eliminating polluting solvents coming from the desorption of a preceding sample and/or solvents present in the surrounding environment.

Abstract: A hydrogen sensor includes a first electrode 3 and a second electrode 4 provided in contact with a proton conduction layer 2; a gas diffusion controlling portion 6 provided between a measurement gas atmosphere and the first electrode 3; and a support element (1a, 1b) for supporting the proton conduction layer 6, the first electrode 3, the second electrode 4, and the gas diffusion controlling portion 6. Hydrogen contained in a measurement gas introduced via the gas diffusion controlling portion 6 is dissociated, decomposed, or reacted by applying a voltage between the first electrode 3 and the second electrode 4 to thereby generate protons. Hydrogen concentration is obtained on the basis of a limiting current generated as a result of the generated protons being pumped out via the proton conduction layer 2 from the first electrode 3 side of the proton conduction layer to the second electrode 4 side of the proton conduction layer.

Abstract: Semiconductor gas sensors with improved selectivity to target gases are provided by having a semiconductor gas-sensing layer and a layer thereon of microporous ceramic oxide having catalytic activity.

Abstract: A sensing system includes a ring oscillator that emits electromagnetic radiation at a characteristic frequency. The ring oscillator comprises an odd number plurality of inverters that are electrically connected in series. The sensing system also comprises a temperature stabilized voltage source that is used to supply voltage to the inverters of the ring oscillator. A sensing load for sensing a change in a preselected environmental condition is operably connected to the ring oscillator. When the load senses the preselected environmental condition, the sensing load alters the characteristic frequency of the ring oscillator and hence the electromagnetic radiation as emitted by the ring oscillator. A pick-up antenna receives the electromagnetic radiation as emitted by the ring oscillator and detection electronics, operably coupled to the pick-up antenna, measure the frequency of the electromagnetic radiation as received by the pick-up antenna.

Abstract: A diagnostic system for monitoring catalyst performance in an exhaust system comprises a plurality of treatment devices catalytically treating an exhaust gas stream, and a plurality of gas sensors for monitoring the catalyst performance of the treatment devices to determine when sulfur poisoning occurs. An on-board diagnostic system receives signals from the gas sensors, and, based upon response time differentials between sensors, determines whether the treatment devices are experiencing sulfur poisoning.

Abstract: An electronic system for selectively detecting and identifying a plurality of chemical species, which comprises an array of nanostructure sensing devices, is disclosed. Within the array, there are at least two different selectivities for sensing among the nanostructure sensing devices. Methods for fabricating the electronic system are also disclosed. The methods involve modifiying nanostructures within the devices to have different selectivity for sensing chemical species. Modification can involve chemical, electrochemical, and self-limiting point defect reactions. Reactants for these reactions can be supplied using a bath method or a chemical jet method. Methods for using the arrays of nanostructure sensing devices to detect and identify a plurality of chemical species are also provided.

Abstract: Sensors and methods of monitoring for the presence of gas phase materials by detecting the formation of films based on the gas phase material are disclosed. Advantageously, some gas phase materials preferentially deposit on specific surfaces. As a result, selective detection of those gas phase materials can be obtained by detecting films deposited on those detection surfaces. Examples of gas phase materials that may be detected include RuO4, IrO4 and RhO4.

Abstract: The present invention provides methods for detecting the presence of an analyte indicative of various medical conditions, including halitosis, periodontal disease and other diseases are also disclosed.

Abstract: Biochemical devices comprising a sensing surface that is at least partially covered by a nanocrystalline metal oxide semiconductor film which provides a recipient surface for immobilizing biochemical species on. The film has a mesoporous surface that gives up to a 1000 increase in biochemical species adsorption when compared to a flat surface. The biochemical devices comprising these surfaces can be optical and electrochemical biosensors and reactors for synthetic or biodegradation reactions.

Abstract: An improved on-stream analyzer for monitoring sulfur or nitrogen content of liquid petroleum or beverage products is described. It consists of the following main components: a sample injector for injecting predetermined fixed volumes of the liquid into a thermal oxidizer (pyrolyzer) at a preset, controlled rate, a thermal oxidizer in which an inert carrier gas and oxygen are introduced at measured and preset, controlled rates to thermally oxidize the sample at a temperature of about 1050° C., sample conditioner to control the relative humidity and temperature of the resulting gas mixture, an electrochemical cell sensitive to sulfur dioxide (SO2) or NO to measure the concentration of SO2 or NO in the gas mixture, and a programmable logic controller (PLC) to calculate the sulfur content of the original sample and manage the analyzer.

Abstract: A diagnostic system for monitoring catalyst performance in an exhaust system comprises a plurality of treatment devices catalytically treating an exhaust gas stream, and a plurality of gas sensors for monitoring the catalyst performance of the treatment devices to determine when sulfur poisoning occurs. An on-board diagnostic system receives signals from the gas sensors, and, based upon response time differentials between sensors, determines whether the treatment devices are experiencing sulfur poisoning.

Abstract: A gas sensor comprising a sensor element including an organic-inorganic hybrid material. The sensor element has layers of an inorganic compound and an organic compound intercalated between the layers of an inorganic compound.

Abstract: Polymeric compositions are provided for use in preparing sensors for the detection of extremely hazardous substances in the environment, such as chemical warfare agents. The polymers are inherently conductive and do not require the use of doping agents to achieve conductivity. The polymers are formulated with appropriate additives which are reactive with the hazardous substances, and are used to prepare sensors. The sensors can be assembled into an array and incorporated into monitoring devices which are highly accurate and relatively inexpensive.

Abstract: A method and apparatus is provided for detection of volatile products from a sample using a transducer which changes voltage as a function of contact of the volatile products with the transducer to produce a gas signature of the volatile products and a spectrophotometer to analyze the volatile products to produce a spectral footprint of the volatile products. The apparatus and method are used to detect spoilage of a biological material, such as a food. The apparatus is also used to detect microorganisms and by comparing the gas signature and spectral footprint to a library of gas signatures and spectral footprints, the apparatus enables identification of the microorganisms and in particular identification of pathogenic microorganisms.

Abstract: A gas sensor for the detection of gases comprises a housing and an active element disposed within the housing. The active element is surrounded by a porous insulating material having a bulk density no greater than 0.15 g/cc. Another gas sensor comprises an active element surrounded by a porous insulating material having a surface area no greater than approximately 200 m2/cc. Another gas sensor comprises a copper compound positioned so that gas contacts the copper compound before contacting the active element. Another gas sensor comprises an active element surrounded by a porous material having an average pore size of at least approximately 100 Å. Another gas sensor comprises a heating element surrounded by a porous material that supports a catalyst.

Abstract: A hydrocarbon detector (20) includes a gas stream delivery element (26) configured to discharge a carrier gas (70) onto a surface (24). The carrier gas (70) serves to volatilize a hydrocarbon presence (22) from the surface (24). A gas stream recovery element (28) is configured to aspirate a sample gas (78) formed from the carrier gas (70) combined with the hydrocarbon presence (22) volatilized from the surface (24). A hydrocarbon sensor (58) detects the hydrocarbon presence (22) in the sample gas (78) and generates an output signal indicative of the hydrocarbon presence (22). An indicator (80) receives the output signal and indicates the hydrocarbon presence (22) in the sample gas (78). A heat source (72) coupled to the gas stream delivery element (26) heats the carrier gas (70) to further aid in the volatilization of the hydrocarbon presence (22).