Abstract: A communications device for use with a protective helmet having a headband is provided. Generally, the communications device provides support member for a bone conduction microphone that is easily added to and removed from the protective helmet, allowing the communications device to be readily used with both new and existing protective helmets. While in use, support member positions the bone conduction microphone between the headband and a user's head, preferably between the napestrap and the center of the back of the user's head. The communications device can be used with any type of protective helmet, such as a fireman's helmet, a military helmet, a hard-hat, etc.

Abstract: The present invention relates to a photoacoustic gas sensor utilizing diffusion having a sensing volume and an acoustic pressure sensor volume containing an acoustic pressure sensor such that the fluid connection between the sensing volume and the acoustic pressure sensor volume restricts the flow of analyte gas therethrough but does not restrict the transmission of the photoacoustic signal therethrough.

Abstract: A headband for use in a headgear support includes a first end section having a plurality of connectors extending latitudinally from a lateral surface of the first end section. The headband also includes a second end section having a fastener attached adjacent the end thereof. The fastener includes a flexible lever arm and a cooperating connector biased in an engagement position with at least one of the plurality of connectors of the first end section to hold the headband in a selected loop configuration. The flexible lever arm is movable to a release position upon application of force thereto to cause the cooperating connector to disengage from the at least one the plurality of connectors of the first end section to enable increasing the size of the loop of the headband. The plurality of connectors of the first end section can, for example, be ratchet teeth.

Abstract: The present invention relates to a device for accomplishing noise reduction in a photoacoustic gas detector using a sound damping element and/or a background or reference microphone where a preferably larger external volume that acts as a sound damping element (SDE) is coupled to a smaller volume through which the gas diffuses. The coupling is accomplished in such a way that the externally generated sound waves incident upon the photoacoustic detector are adequately attenuated by the larger volume SDE without adversely affecting diffusion of the gaseous species of interest through the smaller volume for measurement by the detector. Preferably this is accomplished by coupling the larger SDE volume to the smaller gas diffusion volume by a long and thin pressure channel.

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

Abstract: A neck seal for use in a protective hood includes an inner section including a passage for donning. The inner section is fabricated from an elastomeric material to form a seal around a neck of a user. The neck seal also includes an outer section adhered to the inner section. The outer section is fabricated from a material heat sealable to a hood covering material. In one embodiment, the elastomeric material of the inner section is a latex material. The outer section can, for example, be fabricated from a thermoplastic material. In one embodiment the thermoplastic material is a polyurethane such as a polyester-based polyurethane.

Abstract: An instrument system includes an instrument assembly having at least one fitting projecting therefrom. The instrument system further includes at least a first housing member including at least one alignment member located therein. The alignment member preferably includes at least one sloped surface which slopes toward at least one seating adapted to seat the at least one fitting of the instrument assembly. The instrument system further includes a second housing member which forms an explosion-proof enclosure with the first housing member to enclose the instrument assembly. The second housing member preferably forms an explosion-proof enclosure with the first housing member via cooperating threading. The instrument assembly can, for example, include electrical components for a combustible gas sensor.

Abstract: The present invention provides a full body harness which can include curved webbing, a spreading back pad and/or leg buckles which improve the comfort, use and performance of the harness. Preferably, the harness uses five pieces of webbing, namely, two curved webbing shoulder straps, two identical leg straps, and a subpelvic strap. The harness can also have a spreading back pad which helps to keep the shoulder straps from riding up onto the neck of the wearer.

Abstract: A connector includes a first housing section having a plurality of electrically conductive contacts therein. The connector also includes a second housing section including a plurality of electrically conductive contacts that can form an electrical connection with the contacts of the first housing section. The first housing section and the second housing section are removably connectable and are capable of forming an explosion proof or flame proof housing when connected. The contacts of at least one of the second housing section and the first housing section are movable relative to their respective housing section to align the contacts of the second housing and the contacts of the first housing section during connection of the second housing section to the first housing section.

Abstract: A rebar anchorage system for a horizontal lifeline is described as well as the method of installing the same. Preferably, two triangular frames are secured to vertically extending rebar by eight sets of J-bolts and speed nuts. The frames are preferably made of tubular steel, and may be attached to the vertically extending rebar by one workman. Two or more rebar lifeline anchors may be used in combination to secure the ends of a horizontal lifeline. Three or more anchors can be used to secure two or more lifelines that are perpendicular to each other, such as along the outer, leading edges of a construction site.

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: An instrument system includes an instrument assembly having at least one fitting projecting therefrom. The instrument system further includes at least a first housing member including at least one alignment member located therein. The alignment member preferably includes at least one sloped surface which slopes toward at least one seating adapted to seat the at least one fitting of the instrument assembly. The instrument system further includes a second housing member which forms an explosion-proof enclosure with the first housing member to enclose the instrument assembly. The second housing member preferably forms an explosion-proof enclosure with the first housing member via cooperating threading. The instrument assembly can, for example, include electrical components for a combustible gas sensor.

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

Abstract: An alignment and connection mechanism for more quickly attaching a mask-mounted regulator to the facepiece of a self-contained breathing apparatus is disclosed. The alignment and connection mechanism provides an alignment member preferably mounted on the regulator and a guide member preferably mounted on the facepiece. The user initially attaches the alignment member to the guide member at a connection point which is visible to the user through the lens of the facepiece when it is being worn. The regulator is then slid down the guide member until it is in proper alignment for connection to the facepiece.

Abstract: A thermal imaging camera having improved durability and ergonomic features including generally a seamless housing encompassing a thermal imaging core, a first handle, and a battery compartment. The housing is preferably positioned at a first end of the first handle and the battery compartment is positioned at the opposite end of the first handle. By positioning the first handle intermediate between the housing and the battery compartment, the center of gravity of the thermal imaging camera coincides generally with the handle when the thermal imaging camera is in use, that is when batteries are present within the battery compartment. The camera can also include a second handle positioned between the housing and the battery compartment, the second handle is preferably oriented generally parallel to and spaced apart from the first handle to facilitate passing of the thermal imaging camera between users. The camera also has improved water resistance, shock-resistance and other operational features.

Abstract: A method of increasing enantioselectivity in a reduction reaction of a prochiral substrate with a borane reagent including a borohydride species (for example, a borohydride stabilized borane-tetrahydrofuran complex) catalyzed by a chiral catalyst includes the step of maintaining the concentration of borohydride species in the borane reagent below approximately 0.005 M during the reduction of the prochiral substrate. A method of increasing enantioselectivity in a reduction reaction of a prochiral substrate with a borane reagent including a borohydride species that is catalyzed by a chiral catalyst includes the step of reducing the detrimental effect the borohydride species has on enantioselectivity by adding a Lewis acid. For example, the prochiral substrate can be a ketone and the chiral catalyst can be a chiral oxazaborolidine.

Abstract: A suspension for a protective helmet having a headband section that encompasses at least a part of a user's head and a crown support section connected to the headband section. The headband section and the crown support section of the suspension are fabricated from an integral piece of material. The suspension system may also have a headband comprising a section of elastic material. Alternatively, the headband may comprise a forward band having a first section to contact the forehead of the user and a second section adapted to be positioned between the user's head and the crown support section of the suspension during use thereof.