Abstract: An underwater acoustical projector consisting of a spaced apart pair of polygonal shaped end plates, a ceramic driver of smaller cross-sectional size than each end plate, positioned between the end plates, and a set of staves secured from one end plate to the other, each stave being bent concavely inwardly towards the driver and being separated from each other by a gap.

Abstract: A speech transmitter for use in gas masks and the like comprises a body member having a central, circular recess in one end thereof and a marginal rim surrounding the recess, a cover member having a complementary central, circular recess in one end thereof and a marginal rim surrounding the recess, the cover member marginal rim being lockingly engageable with the body member marginal rim so as to form an unitary assembly in which the body recess and the cover recess are in coaxially aligned, face-to-face relation and define a membrane chamber, the marginal rims having mating surfaces adapted to secure and radially tension a membrane therebetween; and a membrane having a marginal edge interposed between the mating surfaces and a main body portion disposed within the membrane chamber.

Abstract: The invention disclosed is a process for the preparation of branched hydroxy-terminated aliphatic polyethers having alkyl azide substituents, having a structural formula ##STR1## and a molecular weight of abotu 500 to 40,000, and a process for the preparation thereof which comprises the single step of reacting a solid rubbery polyepichlorohydrin (PECH) of molecular weight of about 0.5-5.0.times.10.sup.6 with epichlorohydrin monomer (ECH) and an ionic azide selected from the group consisting of sodium azide, lithium azide and potassium azide, in a suitable organic solvent at elevated temperature, while agitating. According to a further aspect of the invention, the molecular weight of the polyether product may be controlled by adjusting the weight ratio of ECH:PECH, while maintaining a weight ratio of ionic azide: (ECH+PECH) of about 1:1.

Abstract: A radome-lens comprises a shell of dielectric material having an outer surface in the form of a small circle defined by a sphere and a plane intersecting the sphere, an opening at one end of the shell for reception of an antenna therein, the surface having a central axis which is normal to the plane and extends through the center of the sphere, and an inner surface having a spherical portion centered at a second center disposed along the axis adjacent the first mentioned center but spaced toward the outer surface. When so constructed, the invention functions as a radome in the sense that it houses and protects an antenna in the usual manner and also functions as a lens in the sense that it amplifies the scan angle of the antenna from an angle of less than 90.degree. to 90.degree. or more.

Abstract: An air sampler includes a magazine having a plurality of sampling tubes, and an inlet and an outlet at a sampling position. A tube advancing mechanism sequentially advances the sampling tubes to and from the sampling position. A tube sealing arrangement is provided at the sampling position. An air pump draws air through the inlet, a sampling tube at the sampling position, and the outlet. A control sequentially operates the magazine, obtaining air samples within the sampling tubes.

Abstract: A microwave signal receiving apparatus comprises a delay line for distributing a microwave signal, samplers for sampling the signal spatially along the delay line and producing analog samples, analog-to-digital converters for converting the analog samples to digital samples, and digital memories associated with each converter for storing the digital samples.

Abstract: The disclosure teaches a reconfigurable parameter filter of the type useful in radar ESM systems. The filter has first and second sections adapted to be supplied with first and second binary numbers, respectively. Each section consists of upper and lower limit storage registers and upper and lower limit comparators, the comparators being coupled to an AND gate and responsive to the respective binary number to enable the AND gate if the value of the signal lies within the window set by the storage registers. The two sections can operate on two independent data words or can be coupled to act as a unit on one data word under the control of a mode selecting circuit. As a result the same standardized circuit module can process either one high precision parameter number or two low precision parameter numbers.

Abstract: A novel wall breaching apparatus may be constructed with sufficiently small weight and dimensions that it is effectively portable, while being sufficiently energetic to breach a thick wall. The apparatus consists of a number of similar panels, each including a matrix and a linear shaped charge embedded in the matrix. Each end of the charge is located adjacent an edge of the panel. The panels are configured to be assembled edge to edge in an open condition with the linear shaped charges arranged end to end, or face to face in a closed condition, with the linear shaped charges on the inside of the assembly. Thus, the apparatus may be collapsed to the closed position for storage and transport and assembled in its open condition to produce a single "semi-continuous" linear charge of fixed shape. The arrangement of the shaped charges end to end produces the "semi-continuous" linear shaped charge arrangement without the dimensional penalties associated with a continuous charge of the same size and configuration.

Abstract: A piezoelectrically-driven, resonant-pipe projector has formed therein vents to broaden the response of certain cavities resonances and to increase the response between these resonances. The projector exhibits a relatively high electroacoustical efficiency, is capable of medium to high power output over the operating band, and is not depth dependent or depth limited.

Abstract: The quantity of chemical, e.g. charcoal added to fabric used to produce protective clothing for the military is usually determined by the simple expedient of weighing the fabric or swatches thereof before and after impregnation in a charcoal slurry. This method may result in large errors. A simple, effective method of determining the quantity of charcoal or other chemical being incorporated in a fabric base is to add a magnetic tracer, e.g. magnetite to the chemical prior to impregnation, and to measure the magnetic susceptibility of the fabric on a continuous basis immediately following impregnation. If the magnetic tracer is uniformly mixed with the chemical, the direct correlation between magnetic susceptibility and tracer concentration will provide an accurate indication of tracer and consequently chemical concentration in the fabric.

Abstract: A composition for producing smoke from phosphorus vapor for use in search and rescue markers and a method of producing such composition. The composition comprises a blended mixture of the following ingredients in the following weight percentage ranges:red phosphorus--55% to 80%;oxidizing agent (sodium nitrate or ammonium nitrate)--10% to 30%;metal fuel--5% to 10%;acid absorber--1% to 5%; andsynthetic rubber binder--1% to 8%.Such a composition tends to be more stable and reliable than previous compositions used for this purpose, as well as less hazardous to manufacture. In addition, it permits an increase in the proportion of red phosphorus used, with a resultant increase in burn time and/or flame and smoke emission.

Abstract: A detector for producing an electrical signal proportional to the concentration of ferromagnetic particulate material in a fluid stream includes a sensing coil arranged to form the inductance coil of a radio frequency oscillator arranged to produce an electrical signal at a base frequency, a magnetic trap for producing a magnetic field and a support for supporting the sensing coil and the magnetic trap in juxtaposition to one another such that, when the coil is disposed within or proximate the fluid stream and electrically connected to the oscillator, energization of the magnetic trap causes ferromagnetic particulate material proximate the coil to be attracted toward the coil resulting in a deviation of the frequency of the signal from the base frequency proportional to the concentration of ferromagnetic particulate material in the fluid stream.

Abstract: A ferrous object detector and locator includes a magnetometer sensor and a position sensor controlled by a microprocessor. The device accurately locates and identifies an unknown ferrous object and determines the depth and orientation of a buried ferrous rod. Simultaneous magnetic field measurements from the magnetometer and position information in one or more orthogonal directions from the position sensor are combined and analyzed by the microprocessor using predetermined algorithms to determine the location and identity of the object. The detecetor is capable of detecting location and identity of objects of general shape and size.

Abstract: An improved buoyant pyrotechnic marine marker of the type comprising a water impermeable jacket enclosing a pyrotechnic candle, an ignition device for the candle consisting of a water actuable battery, a candle igniting squib electrically acutated by the battery and circuitry extending between the battery and the squib. The jacket has a gas emission hole for escape of the combustion gases produced by the candle when ignited. The improvement is characterized by a reversible arming mechanism comprising an open ended casing having walls, within which casing is seated a piston with walls slidably cooperating with those of the casing, for axial movement of the piston with respect to the casing. The casing and piston form a chamber adjacent the pyrotechnic candle within which the battery is seated. Guides are provided on confronting overlapping portions of the walls of the casing and piston to permit the piston to slide between an unarmed position and an armed position.

Abstract: An accelerometer for underwater acoustic sensors includes a pair of cylindrical piezoelectric crystals configured in a cantilever mode and having attached thereto an electrode segmented into four equal quadrants. In response to translational motion perpendicular to the axes of the piezoelectric crystals, orthogonal voltage signals are generated, from which the crossed dipole directivity patterns can be obtained. The symmetric use of two such piezoelectric crystals enables spurious responses, to rotational motion about an axis perpendicular to the central axis of a cylindrical container for the crystals, to be avoided.

Abstract: A sensor for resolving the left-right ambiguity encountered in horizontal line hydrophone arrays consists of an orthogonal pair of dipole hydrophones, a monopole hydrophone, and a tilt sensor, the tilt sensor connecting the dipole hydrophones so as to provide a single dipole hydrophone which is always oriented horizontally. The tilt sensor consists of two variable capacitors made from hollow cylinders of high permittivity dielectric material, partially filled with a quantity of liquid mercury which forms the variable inner electrodes of the capacitors. The outer electrodes of the capacitors, on the outside of the cylinders, having a sinusoidally-shaped perimeter and being oriented at right angles to each other, are connected to the crossed dipoles in order to provide the required horizontal dipole hydrophone.

Abstract: A spin rig for spinning wind tunnel models has a support mountable on a sting, bearings for mounting the model on the support and an electric motor mounted on the support, inside the model. The motor has a stator fixed to the support and a rotor that is connected to the model. With a D.C. motor of high coercive force permanent magnet stator, the spin rig can be accommodated within a model small enough to be used in small wind tunnels. Tests can be run at constant, controlled spin. Model development costs are significantly reduced.

Abstract: A general purpose potentiostatic test system, used to provide potentiostatic control of test electrodes using a multiplexer in both the anodic and cathodic regimes. A built-in data switching and measurement subsystem enables rapid and precise determination of the set potentials as well as the test electrode currents. All the test electrodes can be placed in the same test tank and use a single auxiliary electrode.

Abstract: The invention disclosed is a burn wound-adherent dressing material comprising a complex of gelatin and a water-soluble resin material such as polyethylenimine. The dressing material may be in the form of a preformed film or in the form of an aqueous coating which sets to a gel and dries to a continuous wound-adherent film in situ.

Abstract: The orientation of a moving platform with respect to a magnetic field is determined by rotating a 3-component vector magnetometer mounted on the platform about at least two axes in the magnetic field. Changes in the signals from the magnetometer are monitored, and the direction of the magnetic field relative to the platform is computed from the signal changes. It is not necessary to know the DC bias of each magnetometer channel or the component of the background magnetic field along each axis of the magnetometer.