Abstract: A method of stabilizing borane-tetrahydrofuran complex comprises the step of maintaining the temperature of the borane-tetrahydrofuran complex at or below 20.degree. C. A method of reacting a borane reagent with a substrate comprises the steps of heating the borane reagent and the substrate in a reaction vessel and preventing escape of evolved diborane from the reaction vessel. Preferably, a reaction vessel containing a borane reagent and a substrate is maintained under at greater than atmospheric pressure with back-pressure regulation.

Abstract: The present invention provides an electrochemical sensor for the detection of hydrogen cyanide. In general, the electrochemical sensor includes a housing having disposed therein a working electrode, a reference electrode and a counter electrode. The electrochemically active surfaces of the working electrode and reference electrode preferably comprise silver. Electrical connection is maintained between the working electrode and the counter electrode via an organic electrolyte present within the housing. The electrochemical gas sensor preferably further comprises circuitry for maintaining the working electrode at a potential in the range of approximately +40 mV to approximately -40 mV versus the silver reference electrode. Most preferably, the electrochemical gas sensor comprises circuitry for maintaining the working electrode at a potential of approximately 0 mV versus the silver reference electrode. The present invention also provides a method of using such a sensor to detect hydrogen cyanide.

Abstract: A deformable, pad-type filter is provided which does not have a frame but instead uses two filter elements, at least one having a non-planar configuration in a stress-free condition, which are preferably joined along an outer edge to form an inner chamber. A connector is located in and attached to one of the filter elements, the connector having a rigid connector platform which projects radially outward from the connector to enable a user's fingers to grasp the perimeter of the connector platform to twist or otherwise manipulate the filter for connection or disconnection to a respirator facepiece without damage to the filter material.

Abstract: The present invention provides an adjustable headband for protective headgear with a ratchet mechanism having different resistances. The adjustable headband utilizes a ring gear assembly having a plurality of radially projecting teeth thereon. Each of the projecting teeth of the ring gear assembly has a first tooth side and a second tooth side which is different from the first tooth side. For example, each tooth of the ring gear assembly preferably has a first tooth angle on the first tooth side and a second, different tooth angle on a second tooth side. A spring assembly having at least one spring tooth projecting radially therefrom is connected to the adjustment knob. The spring assembly is positioned such that the at least one spring tooth meshes with the teeth of the ring gear assembly to provide resistance to the rotation of the adjustment knob.

Abstract: Accordingly, the present invention provides an electrochemical sensor comprising at least two electrochemically active electrodes, a non-aqueous electrolyte system and a diffusion barrier membrane through which the analyte in its gas phase is mobile but through which the non-aqueous electrolyte system is substantially immobile. The diffusion barrier membrane thus allows an analyte in its gas phase to enter the sensor, while substantially preventing the non-aqueous electrolyte from exiting the sensor.

Abstract: The present invention provides an electrochemical sensor for the detection of hydrogen chloride. In general, the electrochemical sensor comprises a housing having disposed therein a working electrode, a reference electrode and a counter electrode. The electrochemically active surface of the working electrode preferably comprises a gold film having a thickness of approximately 1000 to 3000 .ANG.. Electrical connection is maintained between the working electrode and the counter electrode via an electrolyte present within the housing. The electrochemical gas sensor preferably further comprises circuitry for maintaining the working electrode at a potential in the range of approximately 1025 to approximately 1400 mV versus the normal hydrogen electrode. The present invention also provides a method of using such a sensor to detect hydrogen chloride.

Abstract: The present invention provides an electrochemical gas sensor for the detection of nitrogen dioxide comprising a housing and a working electrode and a counter electrode disposed within the housing. Each of the working electrode and the counter electrode are fabricated from an electrically conductive carbon. The present sensor also preferably comprises a reference electrode fabricated from an electrically conductive carbon.

Abstract: The present invention provides an electrochemical sensor for the detection of an analyte, wherein the output or response of the electrochemical sensor approximates the dose-response behavior of a living organism upon exposure to the analyte. The electrochemical sensor comprises a housing including an inlet port therein to allow the analyte to enter the housing. The electrochemical sensor further comprises at least a first electrode and a second electrode within the housing. Electrical conductivity is maintained between the first electrode and the second electrode via an electrolyte system present within the housing. The electrochemical sensor further comprises a resistor in series electrical connection with the first electrode and the second electrode.

Abstract: The present invention provides an adjustable, flexible headgear band. The band comprises a first end and a second end which overlap. The first end comprises a plurality of longitudinally spaced slots therein. The second end comprises a resilient fastener formed integrally with the second end. The resilient fastener comprises a channel to slidably receive the first end in overlapping engagement with the second end. The fastener comprises a fastener surface from which at least one flange extends to engage and be seated in one of the plurality of slots of the first end. The fastener surface is resiliently bowable in a direction away from the first end upon application of compressive force to the fastener. Upon application of such compressive force, the at least one flange is unseated from the slot in which it is seated so that the first end can be slid relative to the fastener (and thereby the second end).

Abstract: Synthetic routes for forming alkali metal substituted borohydride compounds include the step of reacting an alkali metal reagent, a hydrogen donor, and a substituted borane. The reactions proceed without the requirement of specialized handling of alkali metal hydrides associated with prior synthetic processes for the production of alkali metal trisubstituted borohydride compounds. A chemical composition comprises solid potassium tri-sec-butyl borohydride.

Abstract: Generally, the present invention provides a high voltage waveform generator for use in an ion mobility spectrometer (IMS) that detects trace concentration level ionic species present in a sample gas stream. The present invention consists of a first electromagnetic transformer having a pair of oscillating circuits that are simultaneously excited by a transformer input winding controlled by a controller such as a power semiconductor device. Each oscillating circuit in the pair includes inductive and capacitive components that generate discrete frequency waveforms corresponding to the fundamental and second Fourier harmonic frequencies of an electric signal that approximates an ideal square wave used in creating a transverse electrical field for transport of ion species through an ion mobility spectrometer. The oscillating circuits are electromagnetically coupled to each other.

Abstract: The present invention relates to a programmable current or voltage sensing circuit for use in measuring concentration levels of combustible gases. Generally, the present invention provides an electrical apparatus for detecting the concentration level of a combustible gas comprising a pair of sensor elements each having an electrical output which is compared to the other for measuring the amount of the gas undergoing combustion. The apparatus also generally comprises a first pair of electrical circuits each connected to one sensor element for controlling the amount of electrical current or voltage at that element, a second electrical circuit connected to both elements for comparing the electrical outputs of the sensor elements to measure the amount of gas undergoing combustion, and a third electrical circuit having a reference output signal for individually controlling the amount of electrical current or voltage generated by each of the first electrical circuits.

Abstract: The present invention provides a self-contained breathing apparatus ("SCBA") having a personal alert safety system ("PASS") fully integrated therewith. The PASS is structurally integrated with the SCBA such that it is protected from damage by both the air cylinder and the frame. The integrated PASS device is not only automatically activated when the SCBA is being used but can still be activated manually if the SCBA is not in service. Additionally, the integrated PASS device utilizes a unique electrical/mechanical connection assembly between its various parts which greatly increases its ruggedness and durability.

Abstract: Generally, the present invention provides a device for heating the sample stream inlet of an ion mobility spectrometry (IMS) sensor. The heating device increases the temperature of the sample stream inlet surface to reduce the amount of time between adsorption and desorption taking place on the surface. This greatly improves the ability of the IMS sensor to follow rapidly changing analyte concentration levels. An alternate preferred embodiment of the present invention provides a flow smoothing device for decreasing the turbulence present in the fluid flow entering the IMS sensor's carrier stream inlet. This flow smoothing insert permits increasing the fluid flow rate entering the IMS sensor's carrier stream inlet to levels which maximize the IMS sensor's measurement sensitivity without causing mixing of the sample and carrier fluid stream flows.

Abstract: The present invention provides a method of reducing copper oxide to improve its acid resistance comprising the step of reacting cupric oxide with a reducing agent selected from the group consisting of morpholine borane, ethylene diamine borane, ethylene diamine bisborane, t-butylamine borane, piperazine borane, imidazole borane, and methoxyethylamine borane to form cuprous oxide.

Abstract: Generally, the present invention provides a recirculating filtration system for use with a transportable ion mobility spectrometer in gas chromatography applications. The transportable recirculating filtration system comprises a pump and a set of filters and flow sensors connected to an ion mobility spectrometry sensor having a gas chromatograph column at its inlet. The IMS sensor's outlet flow is cleaned by the filters and recirculated by the pump back into the IMS sensor as the carrier fluid stream flow. A portion of the IMS sensor's outlet flow equal to the amount of flow introduced into the sensor as the sample is exhausted from the filtration system to maintain a constant total flow volume through the system as the sample is being analyzed. Preferably, the multicapillary column is sealed to a heated transfer line leading to the sample stream inlet of the IMS sensor. The transfer line is preferably maintained at a temperature 10.degree. C.-40.degree. C.

Abstract: Generally, the present invention provides a recirculating filtration system for use with a transportable ion mobility spectrometer. One preferred embodiment of the transportable recirculating filtration system comprises a pump connected with a set of filters and flow sensors to an ion mobility spectrometry (IMS) sensor. The IMS sensor's outlet flow is cleaned by the filters and recirculated by the pump back into the IMS sensor as the carrier fluid stream flow. A portion of the IMS sensor's outlet flow equal to the amount of flow introduced into the sensor is exhausted from the filtration system to maintain a constant total flow volume through the system as the sample is being taken. An alternate preferred embodiment of the present invention provides a transportable recirculating filtration system for measuring an unknown concentration of a selected ionizable contaminant substance such as benzene present in a sample fluid stream in which other substances may coexist.

Abstract: The present invention provides a respirator filter system suitable for filtering toxic agents, including organic vapors, acid gases, formaldehyde, ammonia, and methylamine as well as pesticides, CS and CN tear gases, dusts, mists, fumes and radionuclides from environmental air to be respired by a user of the filter system. In general, the filter system of the present invention includes a cartridge containing a layer of an unimpregnated activated carbon, a layer of an activated carbon impregnated with sulfate, molybdenum and at least one impregnate selected from the group consisting of copper and zinc, and a HEPA filter. Cartridges containing these adsorbents or adsorbents similar to them (in carbon tetrachloride activity and chemistry) have been discovered to be uniquely capable of filtering a broad range of toxic agents.

Abstract: The present invention provides a low-cost alternative to currently available electrochemical sensors. In general, the present invention provides an electrochemical sensor for the detection of an analyte comprising a first metallic housing member and a second metallic housing member. The first metallic housing member and the second metallic housing member are brought together in sealed connection to create a sealed enclosure therebetween. Contained within the enclosure are a first electrode, at which the analyte reacts, and a second electrode, at which a reaction complimentary to the reaction of the analyte at the first electrode takes place. An acidic electrolyte is also contained within the enclosure of the first metallic housing member and the second metallic housing member.

Abstract: An active primary battery containing a lithium anode; an aprotic organic electrolyte; a separator; and a cathode made of silver (II) oxide, mercuric oxide, or a mixture of silver (II) oxide and mercuric oxide is described. The battery exhibits high open circuit and operating voltage under a wide range of current densities. The open circuit voltage of a lithium-silver (II) oxide battery of the present invention is almost double that obtained in a zinc-silver (II) oxide battery. The packaged capacity density, in amp-hrs/cc, is about twice that obtained in a lithium-manganese dioxide battery or a lithium-iodine battery. The packaged energy density, in watt-hours/cc, is also about twice that obtained in a zinc-silver (II) oxide battery, a lithium-manganese dioxide battery, and a lithium-iodine battery.