Abstract: The present disclosure provides an integrated collection, filtration, and analysis system which is configured to automatically collect fluid samples from a surrounding open water environment, isolate floating particles of a target size range, and perform analysis on the collected particles in-situ. The particles may also be filtered by one or more parameters other than size, and also provided herein is a two-stage vortex filter specially adapted to isolate floating particles of a desired density range from a fluid.

Abstract: A portable hemodialysis system is provided including a disposable cartridge and a reused dialysis machine. The disposable cartridge includes a dialysate flow path and a blood flow path which flow in opposite directions through a dialyzer. The disposable cartridge further includes a filter for removing waste products from the dialysate as well as one or more flow sensors for measuring the flow of dialysate in the dialysate flow path. The preferred flow sensor includes a rotatable spoked wheel in the dialysate flow path which is rotated by the flow of dialysate. The spoked wheel includes one or more magnets which are rotated with the rotation of the spoked wheel. The flow sensor further includes a magnetic field sensor in the reused dialysis machine which is connected to a processor for monitoring the rotation of the spoked wheel to determine flow of fluid in the dialysate flow path.

Abstract: Embodiments of the invention relate a charge indicator for determining the mass of a fluid contained within a fluid enclosure, wherein the charge indicator responds to a deformation of a solid component in contact with the fluid and wherein the deformation is a function of the mass of fluid contained within the fluid enclosure.

Abstract: Embodiments of the invention relate to a device for a fluid enclosure. The device includes a sensing device that responds to a change in distance relative to a fluid enclosure. The change in distance is a function of at least one dimension of the fluid enclosure.

Abstract: A bodily fluid drainage assembly having one or more covers and a fluid bag. The fluid bag has a first and a second volume indicator. The first volume indicator is employed by comparing a top level of a fluid with graduations that make up the first volume indicator. The second volume indicator and one of the covers can be used to appreciate an approximate volume of the fluid without directly observing the fluid. Any covers present on the assembly can be removed.

Abstract: A procedure for determining the flow rate of a fluid includes introducing a fluid into a flow member (6) in the form of a series of plugs (20) separated by segments (22) of a carrier phase, measuring the rate of movement of the plugs in the flow member, and determining therefrom the flow rate of the fluid (20, 22).

Abstract: Fuel gauges for fuel supplies for fuel cells are disclosed. Each fuel gauge has a property that is readable by an electrical circuit. These properties are related to the remaining fuel in the fuel supplies. These properties include, but are not limited to, electrical capacitance, magnetic, semi-conducting resistance, bi-metal resistance, and oscillating magnetic field. These fuel gauges are functional at any fuel supply orientation.

Abstract: An improved fluid flow sensor comprising a housing with a fluid inlet and fluid outlet, a valve chamber connected to the fluid inlet, and a movable valve body wherein the valve body moves between a first position, blocking a first outlet in the valve chamber, and a second position blocking a second outlet in the valve chamber; the first outlet of the valve chamber connected to an inlet at the first end of a measuring chamber, and the second outlet of the valve chamber connected to an inlet at the second end of the measuring chamber, with a movable measuring body located in the measuring chamber capable of moving between the first and second ends of the measuring chamber, and the measuring chamber having outlets at the first and second ends, so that the movable bodies switch position in tandem as fluid flows through the system.

Abstract: A unidirectional clutch assembly for coupling an input shaft to a driven shaft, uses an internal shaft positioned within a moveable clutch disc and a stationary clutch disc. The moveable disc has an engaging element for releasably engaging the internal shaft when the moveable clutch disc is rotated in a primary rotation direction by the driven shaft. The stationary clutch disc has a second engaging element for releasably engaging the internal shaft when the internal shaft is rotated relative to the stationary clutch disc in the opposite direction. When the driven shaft rotates in the primary rotational direction, the moveable clutch disc engages, and the stationary clutch disc disengages, the internal shaft, allowing it to rotate freely in the primary rotational direction. When the driven shaft rotates in the opposite direction, the moveable clutch disc disengages, and the stationary clutch disc engages, the internal shaft preventing its rotation.

Abstract: A flow meter with a metering device for intaking and metering a defined volume of a fluid, and with a control unit for controlling the fluid intake of the metering device for determining a flow rate of the fluid.

Abstract: Fuel gauges for fuel supplies for fuel cells are disclosed. Each fuel gauge has a property that is readable by an electrical circuit. These properties are related to the remaining fuel in the fuel supplies. These properties include, but are not limited to, electrical capacitance, magnetic, semi-conducting resistance, bi-metal resistance, and oscillating magnetic field. These fuel gauges are functional at any fuel supply orientation.

Abstract: A fluid volumetric pumping system has a fluid pump and capacitor plates disposed around a pump chamber of the fluid pump. The capacitance between the capacitor plates changes as the volume of fluid in the pump chamber changes. An electrical circuit measures a change in the capacitance between the plates and outputs a signal indicative of the volume of fluid in the pump chamber. The pump having the capacitance sensor of the present invention fluidly connects to a patient. In an embodiment, a peritoneal dialysis system provides dialysate to the patient via the pump, and the capacitance sensor measures the volume of dialysate supplied to and drained from a peritoneal cavity of the patient.

Abstract: A flowmeter is provided for measuring the flow rate of liquids, particularly liquids with solids suspended therein, or corrosive liquids, by measuring a flow without any contact between the sensing elements of the flowmeter and the liquid. The flowmeter is connected to upstream piping and downstream piping. Interconnected with the upstream piping is a first expansion joint, a tapered nozzle and a second expansion joint of smaller diameter. Extending from the second expansion joint is a reversed tapered nozzle connected to the downstream piping. One or more strain gauges, or a strain gauge assembly, is interconnected with the second expansion joint. The force of flow on the tapered nozzle creates a higher velocity flow within the tapered nozzle and then an expansion thereafter. This tends to urge the expansion nozzle, and the second expansion joint connected thereto, towards the upstream piping. Such movement is measured by th7e strain gauges.

Abstract: A liquid meter body including a plastics material bucket 1 which includes a lower portion 3 delimited by a bottom 9 and by a lower side wall 10 and a cylindrical upper portion 4 delimited by an upper side wall. The upper side wall joins onto the lower side wall at a shoulder 5. The lower portion 3 defines a housing 2 for a measuring chamber. The meter body further comprises entry and exit tubes 6, 7 having an external screwthread, said tubes each opening into the housing 2 of the measuring chamber via a bore formed in the lower side wall 10 and respectively forming an injector 11 and an ejector 12. The meter body has an elliptical bottom 9. The bores forming the injector 11 and the ejector 12 are elliptical.

Abstract: Metering equipment for metering fluid flow through an injector valve, comprising metering means and locating means arranged to locate such a valve in fluid communication with the metering means. The metering means are upstream of the locating means.

Abstract: Systems and methods for monitoring a heat treating atmosphere derive from at least one sensor placed in situ in the atmosphere a process variable, which is indicative of the ratio of gaseous hydrogen H2 (g) to water vapor H2O (g) in the atmosphere. The systems and methods use the process variable, e.g., to control the atmosphere, or to record or display the process variable.

Abstract: A sensor for determining an oxygen level in an exhaust gas of an internal combustion engine includes a receptacle arranged in a longitudinal bore of a metallic enclosure for a sensor element. The sensor element is accommodated in a gas-tight manner using a sensor element seal. The receptacle has a measured gas-side ceramic molded component and a connection-side ceramic molded component, which are arranged one behind the other axially. A hollow space is formed between the measured gas-side ceramic molded component and the connection-side ceramic molded component, in which a metallic sealing element is hot-pressed.

Abstract: A measuring sensor for measuring a fluid includes a longitudinally extending housing having first and second ends and having an inlet opening at the first end for the fluid to be measured, and a sensor chip provided in the housing. The sensor chip has a sensor element provided towards the inlet opening and at least one electrically conducting contact provided towards the second end of the housing. The electrically conducting contact is connected to the exterior by a metal jacket lead having an outer metal tube, at least one internal conductor, and a mineral material for electrically insulating the at least one conductor, the outer metal tubing connected in a fluid-tight manner to the second end of the housing.

Abstract: A sensor is constituted by joining a pair of electrodes to a sensor body formed by binding hydrogen occluding metal with binders. Change in the electric resistance between the electrodes and the quantity of hydrogen occluded by the hydrogen occluding metal in the sensor body has a one to one relationship. Therefore, the quantity of hydrogen occluded by the hydrogen occluding metal can be estimated from the resistance value obtained by the sensor.

Abstract: A gas concentration monitor has a pneumatic bridge having two parallel flowpaths containing a first conduit leg and a second conduit leg connected to an input line. Each leg has an entry orifice and an exit orifice through which a portion of the gas sample flows. Orifices need not be of equal size and or kept at the same temperature. A pump is connected to both legs for drawing the sample through the bridge. A condenser or absorber which removes the gas whose concentration is being determined is connected to the first leg between the entry orifice and the exit orifice. A differential pressure gauge measures the differential pressure between the first leg and the second leg which differential pressure changes due to removal of the target gas of measurement interest from the other gas fraction passing through the bridge towards discharge from the bridge. From that measurement one can calculate the concentration in the sample of the gas that was removed by the condenser or absorber.

Abstract: Method and apparatus for analyzing a breath sample provide user-friendly operation and analysis. The method and apparatus provide for automatic operation and coordination of operation of and absorbent sample tube, including desorbing means, a chromatographic precolumn, a chromatographic main column, a detector, a data processor, a sample receiving tube for receiving exhaled breath sample, a sample loop for aspirating a prescribed quantity of breath sample from the sample receiving tube, a sample valve, a standard gas reservoir, and a standard gas valve. All of the foregoing are operated automatically in such that start cycles, detector cycles, fault detection cycles, standardizing, analysis, shutdown and end cycles are performed in a way which allows for straightforward and simple measurement of breath sample by a user.

Abstract: A termite detection system is disclosed herein. The system comprises a sensor and associated microprocessor detect the presence of gases emitted by termites. The processor relays a signal to an appropriate output device to alert a user that the system has detected the presence of termites.

Abstract: A method and apparatus are disclosed for the near simultaneous detection of light emitted from ozone induced chemiluminescence of nitrogen and sulfur species capable of undergoing ozone induced chemiluminescence in a single instrument. A sample containing sulfur and/or nitrogen is first subjected to an oxidative/reductive process which generates ozone reactive nitrogen and sulfur species which are then forwarded to an specially designed ozone/detector chamber. The ozone relative species are brought in contact with ozone in the special chamber and the chemiluminescence of the nitrogen species and the sulfur species are measured and quantitated.

Abstract: An automotive engine exhaust emissions analysis system includes a pump for moving emissions through a conduit to a nitric oxide sensor through a relatively low-volume expansion chamber which is bounded in part by an unconstrained elastic membrane exposed to ambient air.

Abstract: A vehicle trunk detection and release system 10 which detects the presence of an individual within a trunk 14 and which releases the trunk 14, energizes the horn 16, and/or activates the headlights 17 upon such a detection. The system 10 further includes an illuminated touch pad 28 which opens the trunk 14 upon being touched.

Abstract: The present invention provides an apparatus for the analysis of mixed gas components which can perform, in high precision, determination of the . quantities of components contained in a sample gas containing a plurality of the components having molecular weights close to each other and which has a Fourier transform mass spectrometric means for ionizing a sample gas, applying a high frequency electric field to the ionized gas to induce cyclotron resonance, detecting the cyclotron resonance as a high-frequency decaying electric signal, and converting the resulting high-frequency decaying electric signal to a frequency-domain signal and a wavelength variable light irradiating means for irradiating a light of a single wavelength to ionize the molecules of the components constituting the sample gas, said irradiating means being able to vary the wavelength and/or intensity of the irradiation light.

Abstract: A system that can accurately monitor and control low concentrations of ethylene gas includes a test chamber configured to receive sample gas potentially containing an ethylene concentration and ozone, a detector configured to receive light produced during a reaction between the ethylene and ozone and to produce signals related thereto, and a computer connected to the detector to process the signals to determine therefrom a value of the concentration of ethylene in the sample gas. The supply for the system can include a four way valve configured to receive pressurized gas at one input and a test chamber. A piston is journaled in the test chamber with a drive end disposed in a drive chamber and a reaction end defining with walls of the test chamber a variable volume reaction chamber. The drive end of the piston is pneumatically connected to two ports of the four way valve to provide motive force to the piston.

Abstract: Disclosed is a method for operating a sensor to differentiate between first and second analytes in a sample. The method comprises the steps of determining a input profile for the sensor which will enhance the difference in the output profiles of the sensor as between the first analyte and the second analyte; determining a first analyte output profile as observed when the input profile is applied to the sensor; determining a second analyte output profile as observed when the temperature profile is applied to the sensor; introducing the sensor to the sample while applying the temperature profile to the sensor, thereby obtaining a sample output profile; and evaluating the sample output profile as against the first and second analyte output profiles to thereby determine which of the analytes is present in the sample.

Abstract: A continuous emissions monitoring system for continuously monitoring and evaluating air flow samples from a plurality of emission sites. The monitoring system includes a microprocessor controlled Fourier transform infrared scanning laser system for identifying and quantifying compounds in the air flow samples based on known spectral absorption bands. The monitoring system also includes an auxiliary gas chromatograph for separating and analyzing compounds belonging to a common family which exhibit interference patterns or overlapping spectral bands. The auxiliary gas chromatograph is employed in cases where the infrared scanning laser system detects high levels of compounds, above a predetermined threshold level, exhibiting such interference patterns, or when an unknown compound is detected by the infrared scanning laser system.

Abstract: Chemical sensors for detecting analytes in fluids comprise first and second conductive elements (e.g., electrical leads) electrically coupled to and separated by a chemically sensitive resistor which provides an electrical path between the conductive elements. The resistor comprises a plurality of alternating nonconductive regions (comprising a nonconductive organic polymer) and conductive regions (comprising a conductive material) transverse to the electrical path. The resistor provides a difference in resistance between the conductive elements when contacted with a fluid comprising a chemical analyte at a first concentration, than when contacted with a fluid comprising the chemical analyte at a second different concentration. Arrays of such sensors are constructed with at least two sensors having different chemically sensitive resistors providing dissimilar such differences in resistance.

Abstract: A vapor sensing device that is sufficiently small and lightweight to be handheld, and also modular so as to allow the device to be conveniently adapted for use in sensing the presence and concentration of a wide variety of specified vapors. The device provides these benefits using a sensor module that incorporates a sample chamber and a plurality of sensors, located on a chip releasably carried within or adjacent to the sample chamber. Optionally, the sensor module can be configured to be releasably plugged into a receptacle formed in the device. Vapors are directed to pass through the sample chamber, whereupon the sensors provide a distinct combination of electrical signals in response to each. The sensors of the sensor module can take the form of chemically sensitive resistors having resistances that vary according to the identity and concentration of an adjacent vapor.

Abstract: A method for testing for leakage currents in an oxygen probe, in particular a planar lambda probe, having at least one heating element, one external electrode and one internal electrode, and a solid electrolyte arranged between the electrodes, a first voltage being applied to the heating element. A second voltage is applied to at least one of the electrodes, the second voltage being selected so that the potential difference between the electrode and at least one area of the heating element is positive.

Abstract: A method and apparatus for real time gas analysis involving determining individual concentrations of fluid constituents in a mixture of known constituents by measuring properties of the mixture and solving a set of equations, which relate the individual gas concentrations to the measured properties of the mixture, for the unknown individual gas concentrations. The individual concentrations of four gasses in a mixture are determined by: passing the mixture through a flowmeter, a capillary, an orifice, and a sonic oscillator; transducing temperature, pressure and acoustic frequency measurements taken from the sensors; determining the density, viscosity, and the specific heat of the mixture; forming three equations which respectively relate these three properties to individual gas concentrations; and solving the three equations and the constitutive equation which requires that the sum of the concentrations equal unity, for the four unknown individual gas concentrations.

Abstract: The present invention provides a system and method for thermally curing polymeric coated substrates by effective drying of solvents used in the production of the coated component. A feedback system coupled to a heating apparatus is comprised of one or more gas sensors internal or external to the heating apparatus to provide monitoring of the quantity of solvent gases being generated. The present invention allows the curing process to be precisely controlled, where, for example, a predetermined concentration of solvent gases input to the gas sensor can trigger the heating process to be stopped or to provide for a controlled cool down period for curing of the photoresist substrate. A controller coupled between the gas sensor and the heating apparatus may also contain temperature and/or time controls for varying the output of the heating apparatus in response to indications from the gas sensor.

Abstract: The present invention provides a gas sensor element having physical, electrical and chemical properties capable of detecting methane and carbon monoxide selectively with 1 intergrated filtering, catalyzing sensor by improving gas selectivity of the semiconductor gas sensor. The present invention relates to a gas sensor element, which has a carbon monoxide sensor layer with an ability to function as a catalyst film that blocks carbon monoxide, which impedes detection of methane, and has a layer-built structure where the surface of a methane sensor is covered with the carbon monoxide gas sensor which can be obtained by a gas-phase method.

Abstract: A gas sensor (10) is shown having alternately energized infrared radiation sources (14, 16) disposed in a gas chamber (12) at different distances from an infrared detector (18). Both radiation sources are filtered at the absorbing wavelength of a gas to be monitored with one radiation source located proximate to the detector serving as a "virtual reference". The differential absorption between the two radiation sources is used to determine the concentration of a gas being monitored. In a modified sensor (30) one radiation source is seated in a parabolic recess (34a) in a base plate (34) with the radiation focused on one angled end wall (32d) of a dished shaped cover member (32) and reflected over to a second angled end wall (32e) and into the detector with the radiation sources and the detector attached directly to a circuit board (24) mounting the sensor.

Abstract: An apparatus for sensing low concentration NOx in the atmosphere is disclosed. The apparatus has sensor elements arranged in a flow path of the atmosphere, the resistance of each of said sensor elements varying in response to changes in NOx concentration of the atmosphere; a catalyst arranged between said sensor elements to maintain partial pressures of NO and NO.sub.2 in the atmosphere at an equilibrium state; and measuring means for receiving signals from said sensor elements, one sensor element being contacted with the atmosphere which is not passed through said catalyst and the other sensor element being contacted with the atmosphere which is passed through said catalyst and for determining the concentrations of NO.sub.2 and NO in the atmosphere on the basis of said signals.

Abstract: Diagnosing disease in a body by analyzing a sample from the body for the presence of sulfur compounds.

Abstract: The present invention provides a device for measuring air quality. The device includes at least one sensor with a sensor resistance which is converted via signal processing into an output signal, the gas sensing or air content sensing device having its sensor(s) with electrical resistance that is a function of the air quality, such sensors being connected in an astable flipflop circuit arrangement with a first feedback resistor, a second feedback resistor, a capacitor and a comparator--where the first resistor is coupled between the inverting input and output of the comparator, and the second resistor is coupled between the noninverted input and the output of the comparator, and the sensor(s) is/are coupled between a reference potential and the noninverting input of the comparator. The output signal has a period which is related to the sensor resistance.

Abstract: A detection system with a measuring head, which has a mount for at least one interchangeable sensor, with a component, which is located at the sensor and receives information on the sensor and transmits same to a detection means at the measuring head. Wireless transmission of the sensor information to the measuring head is provided wherein the component is a passive transponder that can be read by supplying external energy in a wireless manner. The transducer includes a data code carrier, in which the sensor information is stored. The detection means has means for supplying the external energy and means for receiving the sensor information.

Abstract: The present invention is an instrument identification system and method for a confined space gas detector used to assure user safety conditions or to collect gas concentration and gas type data at a multitude of known predetermined locations. The system consists of information buttons with touch sensor contacts used for transferring ID type data comprising small stainless steel canisters containing computer memory programmed to store data pertaining to individuals and locations. The system further comprises a receptacle connector with electrical contacts coupled to a confined space gas detector for transferring information from the information buttons, where the gas detector, receptacle and receptacle contacts are contained within a portable integral housing.

Abstract: The presence of a serviceable electrochemical gas sensor (1) in gas detecting apparatus is determined on the basis of the noise in the output of a sensor amplifier. A microcomputer (22) calculates mean, rms or variance values for the noise in the output of the amplifier (20) for successive periods. Each of these values is compared with the threshold and if it falls below the threshold, counter is incremented. When the counter reaches a target value, it is determined fault condition as arisen and an alarm (23) is operated.

Abstract: An air cargo container includes a relatively-rigid housing defining an air-tight interior space of nominal volume within which to receive cargo. The housing substantially maintains the nominal volume of the interior space upon pressurizing or evacuating the interior space relative to ambient pressure, whereby a differential interior pressure is achieved before loading the container aboard an aircraft. Where the differential interior pressure is achieved by pressurizing the interior space, air or another suitable gas is injected under pressure into the housing. Where the differential interior pressure is obtained by evacuating the housing's interior space, or where the process of pressurizing the interior space includes a prior evacuation step, the gases drawn from within the housing are preferably analyzed to detect the presence of contraband within the received cargo. Sensors on the housing confirm that an achieved interior pressure is substantially maintained over time.

Abstract: A method of tagging and detecting objects is disclosed which comprises the steps of: (a) applying a volatile taggant to the object; and (b) subsequently detecting the presence of the taggant by the absorption, transmittance, reflectance, photon emission or fluorescence of the taggant and therefore a proximity of the tagged object. The present invention therefore provides optical sensing means which do not require physical separation of differing compounds for discrimination thereof.

Abstract: A Lambda probe type gas sensor for use in determining the oxygen content of exhaust gases produced by an internal combustion engine includes a sensor element of the electrochemical, solid electrolyte, metallic oxide semiconductor or Lambda air-fuel ratio variety, which sensor element is arranged in a metallic housing and is contacted by connecting cables that are brought out of the metallic housing. These connecting cables are each surrounded by cable insulation that is made of PTFE (Polytetra-fluoroethylene). The surface of the cable insulation has, at least in certain areas, a gas-permeable section that allows a reference atmosphere to arrive inside the cable insulation and, from there, in the metallic housing. The gas-permeable section, on the other hand, prevents ingress of liquids such as fuel, condensed water, etc., This is achieved, for example, by an additionally applied, PTFE film that is placed over the gas-permeable section.

Abstract: Odors are detected and/or recognized by aspirating samples of odors and odorless air mutually exclusively into an aspirating input of a venturi mixing nozzle along with operating or dilution air and having an assessor or panelist sniff the output of the venturi to determine the presence or absence of odor and to identify an odor, if present. The dilution ratio for each sample tested is changed by feeding the sample odor, or odorless air, to the venturi selectively through branches having different sized restrictive orifices thereby obtaining a wide range of dilution ratios for a particular odor. The different branches are selected by electrically operated solenoid valves which are programmably activated by a programmable logic controller (PLC) as the assessor successively tests each sample. For each sample, the assessor makes three sniffing tests by operating a three position rotary switch before making a selection or decision as to the presence and/or recognition of an odor.

Abstract: Method and apparatus for freon and other refrigerant matching, particularly for servicing of air conditioning systems for automotive applications. The matching process is based upon the comparison of resistance or infrared absorption or other data readings of a gas-sensing resistance or infrared absorption or other transducer applied to the refrigerant fluid under test and corresponding data from reference refrigerants.

Abstract: Soil profiles of sports fields, such as those in stadiums and golf courses, are treated by injecting or suctioning gases and water by means of buried horizontal pipe arrays or by vertical penetrators. The extent of soil treatment is controlled by measurement of subsurface gas composition and pressure at locations remote from the point of gas injection or removal, preferably by using a special probe. Penetrators and probes form seals within shaped holes in the soil profile, to control the depth of the layer at which gas is exchanged, and to inhibit atmospheric air flow vertically along the bodies of the devices. For example, a conical penetrator section forms a seal within the hole by compacting the shoulder of a stepped hole and it forms a second seal at the surface of the soil by means of a plate and gasket. In other penetrator installations, a radially expansible material forms the seal. Penetrators of one or two part construction may be removably installed in fields, to facilitate re-treatment.

Abstract: A microcantilever potentiometric sensor utilized for detecting and measuring physical and chemical parameters in a sample of media is described. The microcantilevered spring element includes at least one chemical coating on a coated region, that accumulates a surface charge in response to hydrogen ions, redox potential, or ion concentrations in a sample of the media being monitored. The accumulation of surface charge on one surface of the microcantilever, with a differing surface charge on an opposing surface, creates a mechanical stress and a deflection of the spring element. One of a multitude of deflection detection methods may include the use of a laser light source focused on the microcantilever, with a photo-sensitive detector receiving reflected laser impulses. The microcantilevered spring element is approximately 1 to 100 .mu.m long, approximately 1 to 50 .mu.m wide, and approximately 0.3 to 3.0 .mu.m thick. An accuracy of detection of deflections of the cantilever is provided in the range of 0.

Abstract: A device using the failure of a material decomposable by ozone to indicate a predetermined ozone exposure. In the preferred embodiment, a plurality of contact rods stretch latex to varying thicknesses to indicate more than one level of ozone exposure upon failure. The device can be made compact and portable, usable as a personal monitor. In an alternative embodiment, material such as rubber in the shape of O-rings is employed as the material decomposable by ozone.