Abstract: A porous composite membrane is provided comprising a film of porous, expanded polytetrafluoroethylene whose surfaces, both exterior and within its pores, are coated with a metal salt of a perfluoro-cation exchange polymer. Also provided is the method of avoiding false-positive detection of the presence of organic nerve gas agents by a sensor adapted to detect such presence by employing in the sensor a porous composite membrane comprising a film of porous, expanded polytetrafluoroethylene whose surfaces, both exterior and within its pores, are coated with a metal salt of a perfluoro-cation exchange polymer, the composite acting as a scavenger of unwanted gas components which cause the false-positive signals.

Abstract: A solvent leak detecting sensor is provided comprising: (a) a first electrical conductor and a second electrical conductor installed on an electrically insulating substrate in the form of a detection circuit network, the conductors being exposed and separated from each other, (b) the exposed portions of the first conductor and second conductor being covered by a layer of an electrically insulating material which is both water-repellent and which is dissolvable by the solvent that is to be detected, and (c) a top layer covering the layer in "b", this top layer being both porous and electrically conductive. The layer which is both water-repellent and which is dissolvable by the solvent that is to be detected is preferably polyvinylchloride, and the top layer is preferably conductive carbon powder.

Abstract: An integrally molded, combined fuel cell electrode and matrix is provided having a matrix layer containing 3 to 20 weight percent polytetrafluoroethylene (PTFE) and 80 to 97 weight percent inorganic powder, the matrix being integral with an electrode layer of PTFE containing a catalyst. The electrode layer preferably is 40 to 90 weight percent of electrically conductive fine powder, on which the catalyst has been supported, and 10 to 60 weight percent PTFE. Also provided is a method for manufacture of the integral fuel cell electrode and matrix of the invention.

Abstract: A printed circuit is provided wherein the electrically conductive material which forms the circuit elements is embedded within a dielectric substrate. The preferred dielectric substrate is porous, expanded polytetrafluoroethylene.

Abstract: A waterproof, water-vapor-permeable fabric construction is provided comprising a laminate of a water-permeable material such as a polyester fabric bonded to a waterproof, water-vapor-permeable film such as a film of expanded, porous polytetrafluoroethylene, wherein at least a part of the laminate is molded so that it has a permanent curved shape. This fabric construction is useful in various articles of clothing such as hats.

Abstract: An oil leakage detection device is provided having a detection unit comprising: (a) an oil leakage detecting sensor which exhibits a positive resistance-temperature characteristic in response to changes in temperature, connected, in series, to (b) an oil leakage detecting sensor which exhibits a negative resistance-temperature characteristic in response to changes in temperature.

Abstract: An article formed by stiffening the folds of the folded plate structure by applying a low viscosity penetrant along the folds which reacts with the cement to harden it where it has been weakened due to folding. Applications include sandwich panel roof and floor decking and siding for buildings, cylindrical sandwich panels for arch roofs and large pipes or culverts, box beams and girders, and dome roofs.

Abstract: An attachment ring assembly is provided for installation in drain openings. The assembly includes a cylindrical ring body installed in the drain opening, the ring body extending over the entire circumference of the discharge port of the drain opening, the ring body having a relatively small liquid-collecting opening in the lower end of the cylindrical ring. A liquid leak detecting sensor is installed in the liquid-collecting opening. A liquid leak which flows into the drain is dammed by the attachment ring assembly and channelled to flow into the liquid-collecting opening and to the sensor, thereby substantially reducing the time which would otherwise be required to detect the leak.

Abstract: Apparatus, a method for extruding and expanding tubular products of polytetrafluoroethylene (PTFE) and the products produced thereby are provided. In the apparatus, at least one helical groove is placed in the wall of the extruder tip or die. Preferably, at least one groove is machined in the tip having a pitch angle of 45 degrees and at least one groove is machined in the die having a pitch opposite that (135 degrees) of the tip groove. In the expanded products produced according to the invention, at least one radial position within the wall of a tube substantially all of the longitudinal axes of the nodes are oriented at an angle between about 85 degrees and about 15 degrees with respect to the longitudinal axis of the tube.

Abstract: A dielectric waveguide for the transmission of electromagnetic waves is provided comprising a core of polytetrafluoroethylene (PTFE), one or more layers of PTFE cladding overwrapped around the core, a mode suppression layer of an electromagnetically lossy material covering the cladding and an electromagnetic shielding layer covering the mode suppression layer. The mode suppression layer is preferably a tape of carbon-filled PTFE. Another electromagnetically lossy material layer may be placed around the shield to absorb any extraneous energy.

Abstract: A device for drawing a small representative sample of air from a laminar flow air stream, such as that flowing through a clean room, is provided, which comprises a gridwork of evenly-spaced tubes having regularly spaced orifices to sample representatively a laminar flow stream of air to determine the number of particles therein. The gridwork of tubes is sized and configured to leave the laminar flow of the air stream substantially undisturbed.

Abstract: An oil leakage sensor element is provided wherein a plurality of electrical conductors are contained within and separated from each other by a continuously porous polytetrafluoroethylene (PTFE) material containing from 15 to 40 weight percent carbon particles, the carbon particles having irregular shapes and average diameter between 10 and 30 millimicrons, at least a portion of the exterior surfaces of the carbon particles being exposed at the pore walls of the PTFE and extending into the pores. The porous PTFE material is preferably obtained by stretching an extruded, unsintered PTFE film containing the carbon particles, after removal of lubricant, to a draw ratio of 1.5 times or less. The sensor element, in use, is connected between electrodes which, in turn, are connected to an alarm device. Preferably, the sensor is connected to elongate conductors (wires) such that the direction of stretch of the material is aligned with the lengthwise direction of the conductors.

Abstract: An attachment bracket for attaching a liquid leakage sensor to a drain opening is provided. The attachment bracket has a funnel-shaped bracket body whose outer circumference is fitted in a liquid-tight relation inside the upper portion of the drain opening, this upper, tapered funnel portion being inclined downwardly toward a central opening leading to the drain. A generally circularly-cylindrical, "C"-shaped wall member of a prescribed height is installed on the upper funnel surface of the bracket body and extends around the circumference of the central opening of the bracket body except in the region of the opening of the "C" of the wall member, and a leak detecting sensor is attached to the bracket body within the opening of the "C" of the wall member. In use, a leak that enters the drain is blocked by the wall member and channelled by the wall member around to the opening of the "C", thereby concentrating the leak to the region of the sensor location more rapidly than would otherwise occur.

Abstract: A reinforced porous dielectric sheet of expanded polytetrafluoroethylene is provided wherein solid plastic reinforcement elements in the form of circular columns or wall-like partitions extending through the dielectric sheet from one surface to the other are distributed within the sheet. The reinforced sheet is useful as a substrate for printed circuit boards. The reinforcement elements are preferably of a tetrafluoroethylene/ethylene copolymer or an epoxy resin.

Abstract: A method is provided for reducing the occurrence of anastomotic intimal hyperplasia in grafts of artery, vein, biologic or synthetic conduits having end-to-side distal anastomosis. The method includes administering a regimen of fractionated heparin to the subject. Administration of the fractionated heparin can be either intravenously, intraperitoneally, subcutaneously or orally. Preferred dosage is 50-80 mg./kg. body weight per day.

Abstract: An improved, inexpensive machinist's clamp apparatus for holding metal workpieces during milling, drilling, shaping or the like is provided. The improved clamp apparatus has a generally "U"-shaped holder removeably affixed to the rear end of a step clamp to be used in conjunction with a step block. Through the "U"-bend is threadingly inserted a thumbscrew having a resilient endpiece affixed thereon, such as a spring or a rubber pad. When the step clamp is adjusted to the desired height on the step block, the thumb-screw is advanced such that the resilient end thereof is forced into tight holding contact with the rear vertical face of the step block, resulting in a combination of step clamp, step block and holder which is rigidly attached so that, when a workpiece is removed, the step clamp does not fall away from the step block, thereby avoiding unnecessary time delays in re-setup. Also provided is a new step block base holder for affixing the step block to the work surface.

Abstract: Means are provided for radiating electromagnetic waves from a receiving end zone of a dielectric line for transmitting electromagnetic waves without the need for a metal horn antenna or a metal waveguide, and matching problems are thereby substantially avoided. Said means are provided by shaping the end of the line to specified contours, by varying the dielectric constant of the material of the line in a gradient longitudinally near the end zone of the line, and by arranging a reflecting mirror or lens to receive the waves emitted from the line. This waveguide is useful in wireless communications, radar transmission and similar applications.

Abstract: A suntanning gauge is provided having a plurality of UV-light absorbing lenses of varying thicknesses affixed to a convenient-to-carry base. Under each lens is a fluorescent material which emits visible light when UV-light impinges upon it. The fluorescent material preferably is placed over a black background under each lens. Associated with each lens are indicia corresponding to the degree of strength of sunscreening compositions, the thinnest lens, for example, having the number 4 near it corresponding to a sun protective factor of 4, and the thickest lens having the number 30 near it corresponding to a sun protective factor of 30, and any desired combinations in between. On any given day, depending on the intensity of the sun, UV-light will penetrate none, one or more of the lenses, and, if a lens is penetrated, the flourescent material under it will glow. The highest indicia near a glowing lens will indicate what degree sun protective factor lotion to apply to avoid skin damage.

Abstract: A flexible, breathable, antistatic, non-flammable, filtering, non-linting, clean and cleanable composite laminate is provided. The laminate comprises a middle layer of a non-flammable fabric, preferably a polyamide or glass fabric, containing an antistatic agent, and a top and bottom layer each containing a sheet of porous, expanded polytetrafluoroethylene bonded to the middle layer by means of an adhesive between the middle layer and the top and bottom layers. Preferably the top and bottom layers comprise (a) a flexible, first layer of hydrophobic material having a moisture vapor transmission rate exceeding 1000 gms./m.sup.2 .multidot.day and an advancing water contact angle exceeding 90 degrees; and (b) a continuous hydrophilic layer attached to the first layer, the hydrophilic layer having a moisture vapor transmission rate exceeding 1000 gms./m.sup.2 .multidot.day and forming a barrier to passage of fluids with low surface tension, wherein the hydrophobic layers are both external to the middle layer.

Abstract: A housing contains a mercury tilt switch in electrical connection with an alarm circuit and has two, relatively long, highly flexible insulated lead wires extending from the tilt switch and housing and being in electrical connection with an alarm within the circuit. The lead wires support the housing containing the switch and extend upwardly therefrom to a support affixed to a window frame or the like, and then are connected to the alarm. The lead wires are at least ten feet long, preferably about fifteen feet long, with the housing and switch being supported by the lead wires in pendulum-like fashion adjacent to, but not contacting, the window. When a disturbance such as an intruder enters the window, the pendulum-like apparatus is disturbed and the alarm is sounded.