Abstract: A compact sensor which maps fingerprints for identification purposes. The sensor consists of an array of pixels with each pixel configured with one or more pickup conductive electrodes surrounded by voltage electrodes of different phases. This configuration performs capacitive differencing to eliminate the large background capacitance without the need for complex sensor circuitry. In addition, the readout lines are electrically shielded from the input voltage lines by an intermediate grounded conductive layer, thereby eliminating the parasitic capacitance and allowing the detection of minute capacitance variation of the finger surface.

Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit using resistive elements for which resistance varies with misalignment in one dimension. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between two conductive layers. Other embodiments measure misalignment between diffusion regions and conductors and between diffusion regions and windows through which other diffusion regions are to be formed. A circuit in accordance with one embodiment includes row and column decoders for independently selecting mask-alignment detection structures to reduce the number of test terminals required to implement the detection structures.

Abstract: The present invention provides an apparatus and method for evaluating the integrity of a seal on liquid-filled container. According to one aspect of the invention, the apparatus comprises a tank for containing a liquid solution and a clamp with a first and second member between which the container is engaged. The clamp is positioned with respect to the tank such that a portion of the container properly situated in the clamp will extend into the tank and contact the liquid solution. A ram and cylinder are operatively connected to the clamp to engage the container. A seat is provided to support a portion of the container such that at least a portion of the container supported by the seat will extend into the tank. A drill is provided to pierce a surface of the container to make an opening. The drill is positioned such that the opening can be made while the container is in the clamp and/or the seat such that at least a portion of the container extends into the tank.

Abstract: A method for real time monitoring fluid in a vessel with a probe having a pair of electrodes immersed in the fluid. The disclosed probe has the electrodes arranged helically on a rod, sized and configured for insertion in an engine dipstick hole. Preferably, the probe has spiral electrode winding up regions different pitch to provide improved impedance response at low fractional Hertz and high (at least one Hertz) frequencies of excitation. In one version with alternating voltage the difference in current magnitude measured at the low and high frequencies is compared with stored known values for known fluid conditions and an electrical signal indicative of fluid condition is generated. Examples with engine drain oil and heavy duty transmission lubricant fluid are presented. The impedance properties measured can determine the percentage remaining useful life (RUL) of the fluid.

Abstract: A method for predicting perforation corrosion in a hem flange. The method includes placing an electrode in the hem flange. The electrode extends substantially the entire length of the hem flange. An electrolyte is introduced into the hem flange so that the electrode is immersed, and the electrochemical impedance spectrum of the hem flange is measured. The measured electrochemical impedance spectrum of the hem flange can be compared to a reference electrochemical impedance spectrum. A collection of reference electrochemical impedance spectra can be created by storing the measured electrochemical impedance spectrum of the hem flange.

Abstract: A portable and nondestructive adhesive tape corrosion sensor which is utilized under actual field or laboratory conditions in detecting coating and substrate degradation using Electrochemical Impedance Spectroscopy (EIS) of coated or uncoated metal structures has been developed. The invention allows for broad applicability, flexibility in utilizing the sensor in various environments without structural compromise and the ability to inspect and evaluate corrosion of the actual structure, regardless of the size, shape, composition, or orientation of the structure. The electrodes may be removed once a measurement is made or remain in the original fixed position so that subsequent measurements may be made with the same electrode. The nondestructive sensor apparatus is comprised of a pressure-sensitive adhesive tape that consists of a conductive film or foil and conductive adhesive overlapping another pressure-sensitive adhesive tape that consists of a conductive film or foil and non-conductive adhesive.

Abstract: A measurement device is disclosed for measuring the conductivity distribution in liquids or multiple phase media flowing in any direction. A grid sensor has electrodes shaped as parallel electroconductive grid bars or wires located in two or three planes and electrically insulated from each other and from their mounting. The electrodes in the individual planes are mutually offset by preferably 90°. One of the planes, the middle plane when three planes are used, forms an exciter plane connected with a pulse generator, whereas the other planes(s) form receiver plane(s) coupled to processing electronics. in the disclosed signal generation process, the electrodes of the exciter plane are successively driven with a symmetrical bipolar rectangular pulse, and all non-driven electrodes are connected with low impedance to the zero potential.

Abstract: A hand-held or permanently attached corrosion sensor is described that uses electrochemical impedance spectroscopy (EIS, also known as AC impedance) to detect coating and structural degradation caused by excessive moisture uptake of coated and uncoated composite laminations or honeycomb or adhesively bonded structures. The hand-held sensor is pressed against the surface of the structure or specimen to be inspected. Alternatively, the sensor electrode may be permanently or temporarily attached. An EIS spectrum can then be obtained in the field or under arbitrary conditions and the degree of moisture uptake or coating or material degradation can be determined from the resultant spectrum. There are no restrictions on the configuration of the structure being inspected. The area of detection is controlled by controlling the extent and degree of wetness of the surface. A dry surface will provide a localized measurement; a wet surface will allow inspection of the wetted area.

Abstract: This invention relates to an on-line statistical process control device for solder paste and residues. The invention consists of electronics hardware, software, and probing systems. The electrical hardware of the invention provides voltage and current measurements of solder paste materials, the software of the invention controls the hardware, provides real-time complex, non-linear least squares curve fitting for equivalent circuit analysis, data storage and retrieval of circuit parameters and behavior, and statistical process control tracking and charting. The probing systems of the invention allows for 2, 3, and 4 probe surface and bulk measurements of the solder paste and residues.

Abstract: There is provided a method and system for evaluating a condition of a surface of a combustion vessel exposed to deposition thereon of a material released during a combustion of a fuel in the combustion vessel during a combustion process. The method preferably comprises the steps of imposing a current on an electrical network arranged relative to the combustion vessel and having at least one electrode and thereafter detecting at least one characteristic of the electrical network during the step of imposing a current on the electrical network. The method further includes the step of evaluating a condition of the deposition exposed surface based upon the at least one detected characteristic of the electrical network.

Abstract: This invention relates to a detecting method and a detecting apparatus for detecting an absorbed hydrogen amount in a hydrogen absorbing tank. An object of the present invention is to to provide a detecting method and a detecting apparatus of absorbed hydrogen amount in a hydrogen absorbing tank, which can detect a hydrogen occlude condition in the hydrogen absorbing tank accurately, irrespective of repeating the absorption and desorption of the hydrogen to and from the hydrogen absorbing tank.

Abstract: A sensor apparatus and electrode configuration within the sensor apparatus for measuring electrical characteristics of an aqueous fibrous composition. The electrode configuration includes an elongated ground electrode and at least one segmented electrode to form an array of measurement electrode cells. The electrode configuration further includes an array of reference electrode cells formed by a plurality of reference electrodes built into the array of measurement electrode cells. The measurement electrode cells and reference electrode cells have a different sensitivity to water weight of the aqueous fibrous composition and the same sensitivity to conductivity of the aqueous fibrous composition. The measurement apparatus obtains simultaneous resistive measurements from both measurement and reference cells and determines the ratio of the measurements such that the affects from conductivity is canceled out of the measurement ratio.

Abstract: The invention involves a method for locating the probe of a scanning tunneling micrograph a predetermined distance from its conducting surface, and specifically the deposition of a monolayer of fullerene C60 onto the conducting plate. The Fullerene C60 molecule is approximately spherical, and a monolayer of fullerene has a thickness of one nanometer. By providing a monolayer of fullerene on the conducting surface and locating the probe on the surface of the monolayer, a distance of one nanometer can be established between the probe tip and the conducting surface.

Abstract: Apparatus and methods for determining the minimum film formation temperature of a latex are disclosed based upon the measurement of the conductivity of the latex as the temperature of the latex is varied. By plotting the latex's conductivity and temperature relationship, the minimum film formation temperature is determined.

Abstract: The apparatus for measuring the intra-muscular fat in carcasses or parts of carcasses or the total content of fat in minced meat has a first pair of electrodes for insertion into a carcass or part of a carcass or into minced meat. An alternating current (AC) generator is connected to these electrodes. Second and third pairs of electrodes are inserted parallel to the first pair. Both the second and third pairs have measurement circuits to measure the voltage and phase between the electrode pairs after insertion. The needle or bar shaped electrodes are tapered and insulated apart from 5-20 mm long free end sections. Electrodes are separated by 10-100 mm with each electrode 10-50 mm from the nearest of the first electrode pair. The portable unit for on-line use has a display output. The AC frequency applied to the first electrode pair may be changed in an exponential series to give different measurements.

Abstract: It has been learned that moissanite and other synthetic stones, including synthetic moissanite and synthetic diamond, are distinguishable from natural diamonds based on differing electrical conductivities. The present invention, therefore, provides an apparatus and method for determining a gem type based on its electrical conductivity. In particular, an electronic circuit including the gem under test as part of a circuit path is used to measure its electrical conductivity and, therefore, gem type. The onerous task of determining whether a gem is moissanite or synthetic diamond involves providing a high voltage across a gem surface greater than a breakdown voltage, typically greater than 300 volts, and measuring a minuscule current that flows through the gem. A first and second contact couple the high voltage to the gem under test, where a low impedance detection circuit is used to flag when the contacts are erroneously contacting each other during a measurement.

Abstract: A method of imaging an object, such as a diseased human heart or bone, in a nontransparent medium, such as the human body, involves placing an array of transmitters and receivers in operational association with the medium. The transmitters generate a harmonic (frequency domain) or pulse (time domain) primary electromagnetic field (EM) which propagates through the medium. The primary field interacts with the object to produce a scattered field, which is recorded by the receivers. The scattered EM field components measured by the receivers are applied as an artificial EM field to generate a backscattering EM field. Cross power spectra of the primary and backscattering fields (in the frequency domain) or cross correlation between these fields (in the time domain) produce a numerical reconstruction of an EM hologram. The desired properties of the medium, such as conductivity or dielectric permittivity, are then derived from this hologram.

Abstract: A measurement apparatus for sensing three properties of materials including a fixed impedance element coupled in series with the sensor array between an input signal and a reference potential (e.g. ground). The sensor array exhibits a variable impedance resulting from changes in physical characteristics of the material. The variable impedance of the sensor array relates to changes in property of the material being sensed which can then be related to changes in other physical characteristics of the material such as weight, chemical composition, and temperature. The reduced size and increased resolution of the sensor array is particularly adaptive to a twin mesh sheetmaking system.

Abstract: The use of Electrical Impedance Tomography (EIT) to map subsurface hydraulic conductivity. EIT can be used to map hydraulic conductivity in the subsurface where measurements of both amplitude and phase are made. Hydraulic conductivity depends on at least two parameters: porosity and a length scale parameter. Electrical Resistance Tomography (ERT) measures and maps electrical conductivity (which can be related to porosity) in three dimensions. By introducing phase measurements along with amplitude, the desired additional measurement of a pertinent length scale can be achieved. Hydraulic conductivity controls the ability to flush unwanted fluid contaminants from the surface. Thus inexpensive maps of hydraulic conductivity would improve planning strategies for subsequent remediation efforts. Fluid permeability is also of importance for oil field exploitation and thus detailed knowledge of fluid permeability distribution in three-dimension (3-D) would be a great boon to petroleum reservoir analysts.

Abstract: On-line measurements of an amount of dissolved solids in a liquid sample are determined by using both conductivity and UV measurements. More particularly, an amount of dissolved solids in a pulp and paper mill process water or effluent is determined by irradiating at least a portion of a liquid sample with ultraviolet light and subsequently measuring an absorption of the light by the liquid sample. Furthermore the conductivity of the liquid sample is measured and subsequently a computation is from a first relationship between the measured absorption of the first wavelength by the liquid sample and the measured conductivity of the liquid sample using a suitably programmed processor.

Abstract: An electrochemical method for measuring localized corrosion and other heterogeneous electrochemical processes is described. A multi-sensor electrode namely the wire beam electrode, integrated by coupling all its wire terminals together, is used to simulate a conventional one-piece metal electrode surface in electrochemical behavior. The working surface of the wire beam electrode is exposed to an electrolyte as a conventional one-piece electrode to allow heterogeneous electrochemical processes such as localized corrosion to occur. Electrochemical parameters at local areas of the wire beam electrode surface are detected by means of wires located at those areas. A zero resistance ammeter is inserted between each selected wire terminal and all other coupled wire terminals to measure the coupling current flowing into or out the selected wire, and thus a coupling current distribution map is produced.

Abstract: An automated coupon monitor for detecting the electrical parameters associated with a pipe, a coupon and a reference electrode utilized with a cathodic protection system. A voltage detector circuit has its output applied to a pair of sample and hold circuits, one for recording E.sub.OFF and the other for recording E.sub.ON. Series connected between the coupon and the pipe is a zero resistance current detector circuit and an interrupter switch for measuring the pipe-coupon current and periodically interrupting that current to permit measurement, sampling and storing of E.sub.OFF. The sample and hold circuits and the interrupter switch are controlled by a microprocessor controller. The circuit provides DC level outputs which can be easily read by a digital multimeter or stored in a data logger for subsequent reading or transmission to another location.

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 measurement apparatus for sensing three properties of materials including a fixed impedance element coupled in series with the sensor array between an input signal and a reference potential (e.g. ground). The sensor array of the apparatus is an electrode configuration which includes a first elongated electrode coupled to the reference potential and second and third segmented elongated electrodes being parallel to and essentially in the same plane as the first elongated electrode. The segments within the second and third electrodes are configured such that the segments in the second electrode are staggered with respect to segments in the third electrode thereby minimizing or eliminating spacing between detection cells within the sensor array, reducing overall size of the sensor array and increasing measurement resolution. The sensor array exhibits a variable impedance resulting from changes in physical characteristics of the material.

Abstract: A conductivity sensor for measuring hematocrit and a sensor housing for a blood analysis instrument using the conductivity sensor are described. The conductivity sensor includes a seven-electrode conductivity measurement cell in which three symmetric pairs of electrodes are arranged on opposite sides of a central electrode. The central electrode is connected to an AC source and the outermost pair of electrodes, which provide a return path for the current, are maintained at a ground or reference potential. The two inner pairs of electrodes measure the voltage drop along the current flow path. This arrangement confines the measurement current and potential within the sensor chamber, thereby preventing the sensor from interfering with other electrochemical sensors that may be provided in the blood analysis instrument. The sensor housing provides a linear arrangement of flow cells defining a fluid flow path through the housing.

Abstract: A hand-held and flexible corrosion sensor is described that uses electrochemical impedance spectroscopy (EIS, also known as AC impedance) to detect coating degradation and corrosion of coated and uncoated metals. The hand-held and flexible corrosion sensor is pressed against the surface of the structure of specimen to be inspected, and may be either straight in structural configuration in the form of a pen or bent in a curved or angled manner to achieve better access to the structure. An EIS spectrum can than be obtained in the field or under arbitrary conditions and the degree of coating or material degradation can be determined from the resultant spectrum. There are no restrictions on the configuration of the structure being inspected. The area of detection is controlled by moderating the extent and degree of wetness of the surface. A dry surface will provide a localized measurement; a wet surface will allow inspection of the wetted area.

Abstract: A method and apparatus for measuring the concentration of unattached Radon progeny in air is described. The method consists of measuring the conductivity of the air or alternatively the concentration of fast ions in the air, and converting the measurement to a concentration of unattached Radon progeny by applying a predetermined ratio found to exist between conductivity and the concentration of unattached Radon progeny on the one hand, or between the concentrations of fast ions and unattached Radon progeny on the other hand. Apparatus for implementing the method includes means for measuring conductivity (or fast ion concentration), means for calculating the concentration of unattached Radon progeny using the predetermined ratios and output means for displaying the result of the calculation.

Abstract: A sensor array for detecting an analyte in a fluid, comprising at least first and second chemically sensitive resistors electrically connected to an electrical measuring apparatus, wherein each of the chemically sensitive resistors comprises a mixture of nonconductive material and a conductive material. Each resistor provides an electrical path through the mixture of nonconductive material and the conductive material. The resistors also provide a difference in resistance between the conductive elements when contacted with a fluid comprising an analyte at a first concentration, than when contacted with an analyte at a second different concentration. A broad range of analytes can be detected using the sensors of the present invention.

Abstract: This invention relates to an on-line statistical process control device for solder paste and residues. The invention consists of electronics hardwa software, and probing systems. The electrical hardware of the invention provides voltage and current measurements of solder paste materials, the software of the invention controls the hardware, provides real-time complex, non-linear least squares curve fitting for equivalent circuit analysis, data storage and retrieval of circuit parameters and behavior, and to statistical process control tracking and charting. The probing systems of the invention allows for 2, 3, and 4 probe surface and bulk measurements of the solder paste and residues.

Abstract: Method and apparatus for detecting in a sample a substance which responds to an applied magnetic field, such as a paramagnetic substance. The sample is placed in an applied magnetic field, and the effect of the sample on a performance characteristic of an electrical conductor is correlated to the presence of the substance. The method and apparatus may be adapted for qualitative and quantitative determination.

Abstract: A process for online measurement of electrical conductivity to control minimum conductivity of fluids, especially rolling oil, which prevents charging and discharging, by controlled addition of conductivity additives. The process measures the time change of conductivity to determine the amount of extremely fine particulate fouling and the degree of impurity of the rolling oil. The process also provides online measurement of the dielectric constant and online measurement of permeability.

Abstract: A method of inspecting a crack in a ceramic substrate that is not exposed on the surface. The method can detect all cracks and make objective judgement possible by expressing the inspection result as numerical data. Conductors are disposed on both faces of a ceramic substrate, wherein one of the conductors is a conductive liquid; the insulation resistance value or an electric property dependent on the insulation resistance is measured with the conductive liquid or other conductors electrically connected to the conductive liquid which are used as electrodes.

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: 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 method of measuring electrical characteristics of a molecule including providing a first metal contact having a major surface, an insulating layer overlying the major surface of the first metal contact and a second metal contact overlying the insulating layer so as to have an edge spaced a molecular distance from the major surface of the first metal contact. A conductive organic molecule including a metal binding group is coupled between the metal contacts.

Abstract: A plasma monitoring and control method and system monitor and control plasma in an electronic device fabrication reactor by sensing the voltage of the radio frequency power that is directed into the plasma producing gas at the input to the plasma producing environment of the electronic device fabrication reactor. The method and system further sense the current and phase angle of the radio frequency power directed to the plasma producing gas at the input to the plasma producing environment. Full load impedance is measured and used in determining characteristics of the plasma environment, including not only discharge and sheath impedances, but also chuck and wafer impedances, primary ground path impedance, and a secondary ground path impedance associated with the plasma environment. This permits end point detection of both deposition and etch processes, as well as advanced process control for electronic device fabrication.

Abstract: An electrically powered integrity checking device for detection of breaches in protective garments under conditions of a potential for exposure to any one of bodily fluids and hazardous fluid materials. The device comprises a connector for electrically connecting a person wearing a protective garment to the device and a second connector to a fluid source. The device comprises a current source, an alarm, with constant monitoring of integrity of each connection during use of the device. A breach in the protective garment allows ingress of fluid through the breach, results in a completed circuit from the current source means, between the person wearing the protective garment and the fluid source, which triggers said alarm. The connector comprises a reusable spring loaded clamping structure which maintains pressure terminal contact with the person.

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: Corrosion is monitored by making a resistance measurement between a contact and an uncorroded or relatively uncorroded portion of the article to be monitored. Changes in the resistance measured are a result of the presence of a corrosion product, or the breakdown of protective coatings by corrosion. The contact may be a sensor washer which is held in place around a threaded stud 6 by nut 12. The washer comprises a steel ring 14 and an electrically conducting ring 18 which is insulated from ring 14 and contacted by circling 21 and conductor wire 23 in resin jacket 22. The measurement may be made on magnesium alloy gearboxes in helicopter. The alloy may be protected by a paint film so that the initial resistance measured is very high.

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: The present invention relates to a method and apparatus which can be used to detect the abnormal operating condition of equipment, such as engines and machinery, the usefulness of the fluid, and the content of wear metals and elemental constituents in the fluid. The method comprises the steps of bringing at least two electrodes into contact with a sample of a fluid to be analyzed; applying a square voltage wave form to the electrodes at a predetermined scan range and scan rate to cause a current to flow between the electrodes; monitoring the current at the electrodes to determine a current output signal; using the current output signal to measure the conductivity of the fluid; and analyzing the sample to determine a content of wear metals and elemental constituents in the sample.

Abstract: A solution of active principle, in ionized form, impregnates a layer (2) forming part of the reservoir (1). A measurement of the quantity of active principle contained in this layer is derived from a measurement of the conductivity of this layer. The measurement device comprises a) first (7) and second (10) electrodes placed on either side of and in electrical contact with at least a part of the layer (2) of the impregnated material of the reservoir, b) means (5) for passing the electric current of predetermined strength through the impregnated material and c) means (6) sensitive to the voltage (V) picked up between the electrodes (7, 10) in order to calculate the quantity of active principle contained in the reservoir.

Abstract: A method for the early detection of electrochemical corrosion and coating degradation utilizing an inexpensive, in situ electrochemical metallic sensor for sensing coating and material degradation, particularly for materials such as aluminum 2024-T3, 7075, 6061, cold rolled steel samples, and coated metal structures such as automobiles, bridges, aircraft, and ships has been developed. The sensor utilizes AC Impedance or Electrochemical impedance spectroscopy (EIS) to acquire a precise, low-frequency impedance signature and is comprised of conductive ink deposited on a coating in the shape of the outline of a quadrilateral or other configuration. The resulting apparatus is comprised of a coated, metallic coupon used as a sensor, while a metallic grid electrode is deposited onto the steel coupon, thereby eliminating the need for a remote or counter electrode (i.e., reduction from a traditional, three-electrode system to a two-electrode system).

Abstract: A sample apparatus includes a sampling valve having a sample inlet through which a sample such as urine is introduced from the outside of the sampling valve to the inside thereof; a sample outlet through which the sample is sent from the inside of the sampling valve to the outside thereof; and a sampling passage for setting apart a predetermined amount of the sample between the sample inlet and sample outlet. It further includes a first electrode section located close to the sample inlet so that the sample can come into contact with the first electrode section, a second electrode section located close to the sample outlet so that the sample can come into contact with the second electrode section, and a sensor circuit for measuring the impedance between the first and second electrode sections and for using the measured impedance to determine whether or not the sampling passage contains a predetermined amount of the sample.

Abstract: Sensing apparatus is disclosed which allows for the determination of the presence, absence or percentage of a conducting medium such as water, by electronic means. The inventive apparatus negates the effect of a false signal generated by contamination of the sensing apparatus. The inventive sensor comprises three or more sensing members attached to a non-conducting substrate with electronically significant distances between pairs of sensing members. An appropriate electrical circuit is connected to the sensing members which converts signals output from the pairs of sensing members into readings which indicate the presence or absence of a conducting medium, notwithstanding the presence or absence of contamination between the sensing members.

Abstract: Methods and apparatus for detecting and utilizing a voltage produced by a variety of materials for process control and analysis purposes.

Abstract: A relative volume fraction probe particularly for use in a multiphase fluid system includes two parallel conductive paths defining therebetween a sample zone within the system. A generating unit generates time varying electrical signals which are inserted into one of the two parallel conductive paths. A time domain reflectometer receives the time varying electrical signals returned by the second of the two parallel conductive paths and, responsive thereto, outputs a curve of impedance versus distance. An analysis unit then calculates the area under the curve, subtracts the calculated area from an area produced when the sample zone consists entirely of material of a first fluid phase, and divides this calculated difference by the difference between an area produced when the sample zone consists entirely of material of the first fluid phase and an area produced when the sample zone consists entirely of material of a second fluid phase. The result is the volume fraction.

Abstract: The composition of an electrically conductive mixture, preferably a mixture of gasoline and alcohol, is measured using a single measurement cell having a first electrode and a second electrode with a measurement space therebetween for receiving a specimen of the mixture. With a specimen of the mixture in the measurement space, the first electrode is alternatively connected to a reference discharge voltage, preferably ground, and to a feedback control voltage. A first operational state encompasses the period when the first electrode is connected to the reference discharge voltage and a second operational state encompasses the period when the first electrode is connected to the feedback control voltage. A first operational state peak voltage is measured during the first operational state, and a peak second operational state voltage is measured during the second operational state.

Abstract: The position of a break in at least one of a pair of rails in an electrically isolated rail segment of a railroad is carried out by measuring current across the ballast between the rails of the segment from one end of the segment when one of the rails in the segment is not broken and subsequently when the rail is broken. A position of the break can be calculated as a function of the ballast current. A linear approximation using the ratio of the ballast current when the rail is broken to the ballast current when the rail is not broken multiplied by the distance of the rail segment from the one end gives a satisfactory approximation of the location of the rail break.

Abstract: A hydrogen sensitive metal alloy contains palladium and titanium to provide a larger change in electrical resistance when exposed to the presence of hydrogen. The alloy is deposited on a substrate and a thin film and connected across electrical circuitry to provide a sensor device that can be used for improved sensitivity and accuracy of hydrogen detection.