Abstract: A hot gas engine, such as a Stirling engine, which comprises a displacer portion and an expander portion with a heat exchanger connected therebetween. The expander portion has an expander piston which is operatively connected to and rotates an expander crankshaft. In like manner, the displacer portion is provided with a displacer piston which is also operatively connected to and rotates with a separate displacer crankshaft. The two crankshafts are synchronized with respect to each other, preferably by means of an idler gear. Banks of displacer pistons can also be provided for operation on a common displacer crankshaft and banks of cooperating expander pistons also can be provided for operation on a common expander crankshaft.

Abstract: Photovoltaic cells having improved performance are fabricated from polycrystalline silicon containing copper segregated at the grain boundaries.

Abstract: A method and apparatus for measuring thermal diffusivity and molecular relaxation processes in a sample material utilizing two light beams, one being a pulsed laser light beam for forming a thermal lens in the sample material, and the other being a relatively low power probe light beam for measuring changes in the refractive index of the sample material during formation and dissipation of the thermal lens. More specifically, a sample material is irradiated by relatively high power, short pulses from a dye laser. Energy from the pulses is absorbed by the sample material, thereby forming a thermal lens in the area of absorption. The pulse repetition rate is chosen so that the thermal lens is substantially dissipated by the time the next pulse reaches the sample material. A probe light beam, which in a specific embodiment is a relatively low power, continuous wave (cw) laser beam, irradiates the thermal lens formed in the sample material.

Abstract: A first embodiment incorporating an actuator including a restraint link adapted to be connected with a pivotal carrier arm for a force transfer gear interposed between the crankshaft for an expander portion of a Stirling engine and a crankshaft for the displacer portion of the engine, said restraint link being releasably supported against axial displacement by releasably trapped hydraulic fluid for selectively establishing a phase angle relationship between the crankshaft and a second embodiment incorporating a hydraulic coupler for use in varying the phase angle of gear-coupled crankshafts for a Stirling engine whereby phase angle changes are obtainable.

Abstract: A hot gas engine in which the expander piston of the engine is connected to an expander crankshaft. A displacer piston of the engine is connected to a separate displacer crankshaft which may or may not be coaxial with the expander crankshaft. A phase angle control mechanism used as a power control for changing the phase angle between the expander and displacer crankshaft is located between the two crankshafts. The phase angle control mechanism comprises a differential-type mechanism comprised of a pair of gears, as for example, bevel gears, one of which is connected to one end of the expander crankshaft and the other of which is connected to the opposite end of the displacer crankshaft. A mating bevel gear is disposed in meshing engagement with the first two bevel gears to provide a phase-angle control between the two crankshafts. Other forms of differential mechanisms may be used including conventional spur gears connected in a differential type arrangement.

Abstract: Aluminum is recovered from solid rocket propellant containing a small amount of oxidizer by depolymerizing and dissolving propellant binder containing functional or hydrolyzable groups in a solution of sodium methoxide in an alcohol solvent optionally containing an aliphatic or aromatic hydrocarbon co-solvent and then filtering the solution to recover substantially all the aluminum in active form.

Abstract: A method for extracting an underground mineral such as coal, which avoids the need for sending personnel underground and which enables the mining of steeply pitched seams of the mineral. The method includes the use of a narrow vehicle which moves underground along the mineral seam and which is connected by pipes or hoses to water pumps at the surface of the earth. The vehicle hydraulically drills pilot holes during its entrances into the seam, and then directs sideward jets at the seam during its withdrawal from each pilot hole to comminute the mineral surrounding the pilot hole and combine it with water into a slurry, so that the slurried mineral can flow down to a location where a pump raises the slurry to the surface.

Abstract: The invention is embodied in a method and apparatus for fabricating an improved solar cell module. The apparatus includes a supply drum for feeding a flexible strip having deposited thereon etched electrical circuitry, a supply drum for feeding into overlying engagement with the flexible strip a flexible tape having a pair of exposed tacky surfaces, and a plurality of rams for receiving and depositing a plurality of solar cells in side-by-side relation on an exposed tacky surface of the tape in electrical contacting engagement with the etched circuitry.

Abstract: An improved cryostat for use in a low or a substantially gravity-free environment adapted to cool an experiment through the use of helium II, or helium in its super fluid state. The cryostat is characterized by a plurality of interchangeable daughter dewars and helium supply or mother dewar having connected therewith a low pressure venting system for converting helium I contained therein to a super fluid state for use as a primary cryogen. Each daughter dewar is adapted to be removably mounted in mated relation on the mother dewar and is characterized by a support for an experiment package, a source of helium to be employed as a secondary cryogen, and a heat pipe suspended therefrom and adapted to be extended into the mother dewar for facilitating cooling of the secondary cryogen whereby a transfer of heat from the package to the primary cryogen, via the secondary cryogen, is accommodated as a film flow of helium II progresses from the heat pipe to the experiment dewar.

Abstract: A speed control device characterized by a reference speed shaft spatially related to a heavy duty shaft, a drive train for driving the reference speed shaft at a constant angular velocity, a drive train for driving the heavy duty shaft at a variable angular velocity and a speed control assembly for continuously comparing the angular velocity of the heavy duty shaft with the angular velocity of the reference speed shaft, and a brake assembly connected to the heavy duty shaft adapted to respond to errors in the angular velocity of the heavy duty shaft for reducing the angular velocity of the heavy duty shaft to that of the reference speed shaft.

Abstract: A method of growing a ribbon crystal wherein a meniscus of molten semiconductor material attached to vertical movable seed is lifted at a rate substantially equal to the rate at which the meniscus freezes, characterized by the steps of continuously sensing the brightness of the growth region of the ribbon in selected areas across the width thereof for detecting changes in the intensity of the brightness of said selected areas, and modifying the temperature of the meniscus and pulling speed in response to changes detected in the intensity for controlling the geometry of the ribbon.

Abstract: In combination with a susceptor particularly suited for use in growing a ribbon crystal employing edge-defined film-fed growth techniques and characterized by a susceptor including a die through which a melt is drawn for forming a crystal ribbon, a pair of jets for directing a stream of fluid coolant along a path extended to impinge on the susceptor in close proximity with the die in non-incident relation with the crystal being grown.

Abstract: A compact cryogenically coolable choked waveguide particularly for low-noise input coupling into a cryogenically cooled device, such as a maser or parametric amplifier, utilizes coaxial stainless steel support tubes surrounding the waveguide and connected in cascade to provide a folded low thermal conduction path. The edges of the tubes connected are welded.

Abstract: Data for use in producing a tomograph of subsoil structure between boreholes is derived by placing spaced geophones in one borehole, and if desired also on the earth surface, and by producing a sequence of shots at spaced apart locations in the other borehole. The signals, detected by each of the geophones from the various shots, are processed either on a time of arrival basis, or on the basis of signal amplitude, to provide information of the characteristics of a large number of incremental areas (pixels) between the boreholes. Such information is useable to produce a tomograph of the subsoil structure between the boreholes. By processing signals of relatively high frequencies, e.g., up to 1000 Hz, and by closely spacing the geophones, a high resolution tomograph can be produced.

Abstract: A system for generating within a single frame of photographic film a quadrified image including images of angularly, including orthogonally, related fields of view of a near field three dimensional object and characterized by a first subsystem including a plurality of reflective surfaces for imaging a first field of view of the object at one quadrant of the quadrifid image, a second subsystem including a plurality of reflecting surfaces for imaging a second field of view of the object at a second quadrant of the frame and a third subsystem including a plurality of reflecting surfaces for reflectively imaging a third field of view of the object at a third quadrant of the quadrifid image, all of which have identical path lengths to the object photographed.

Abstract: Addition of a small amount, for example 1% by weight, of a liquid silicone oil to a metal containing solid rocket propellant provides a significant reduction in heat transfer to the inert nozzle walls eliminating metal oxide slag collection and blockage of the nozzle and increases burning rate by about 5 to 10% improving ballistic performance.

Abstract: Microstructural evaluation tests performed on Cu-doped, Ti-doped and Cu/Ti doped p-type silicon single crystal wafers, before and after the solar cell fabrication, and evaluation of both dark forward and reverse I-V characteristic records for the solar cells produced from the corresponding silicon wafers, show that Cu mitigates the unfavorable effects of Ti, and thus provides for higher conversion efficiency, thereby providing an economical way to reduce the deleterious effects of titanium, one of the impurities present in metallurgical grade silicon material.

Abstract: Enhanced recovery of ammonium perchlorate from waste solid rocket propellant is effected by leaching shredded particles of the propellant with an aqueous leach solution containing a low concentration of surface active agent while stirring the suspension.

Abstract: A probe is described which can be installed in a side hole that extends from a bore hole in the earth, to assess the permeability of the strata surrounding the borehole. The probe is elongated and has a plurality of seals spaced therealong and sealed to the walls of the side hole to form a plurality of chambers sealed from one another. A tracer fluid injector on the probe can inject a tracer fluid into one of the chambers, while a tracer fluid detector located in another chamber can detect the tracer fluid, to thereby sense the permeability of the strata surrounding the side hole. The probe can include a train of modules, with each module having an inflatable packer which is inflated by the difference between the borehole pressure and the strata pressure.

Abstract: A ball valve particularly suited for use in the handling of highly corrosive fluids characterized by a valve housing formed of communicating segments of quartz tubing, a pair of communicating sockets disposed in coaxial alignment with selected segments of tubing for establishing a pair of inlet ports communicating with a common outlet port, a ball formed of quartz material supported for displacement between the sockets and configured to be received alternately thereby, and a valve actuator including a rod attached to the ball for selectively displacing the ball relative to each of the sockets for controlling fluid flow through the inlet ports.