A method for laser beam amplification by means of free electron laser techniques is described. With wiggler magnetic field strength B/sub w/ and wavelength lambda/sub w/ = 2..pi../k/sub w/ regarded as variable parameters, the method(s) impose conditions such as substantial constancy of B/sub w//k/sub w/ or k/sub w/ or B/sub w/ and k/sub w/ (alternating), coupled with a choice of either constant resonant phase angle or programmed phase space bucket area.

A surface is textured by co-sputter etching with a target and a seed material with the surface at a pre-selected temperature. By pre-selecting the temperature of the surface while sputter etching, it is possible to predetermine the reflectance properties of the etched surface. The surface may be textured to absorb sunlight efficiently and have minimal emittance in the infrared region so as to be well-suited for use as a solar absorber for photothermal energy conversion.

A high efficiency, free electron laser is described utilizing a circular relativistic electron beam accelerator and a circular whispering mode optical waveguide for guiding optical energy in a circular path in the circular relativistic electron beam accelerator such that the circular relativistic electron beam and the optical energy are spatially contiguous in a resonant condition for free electron laser operation. Both a betatron and synchrotron are disclosed for use in the present invention. A free electron laser wiggler is disposed around the circular relativistic electron beam accelerator for generating a periodic magnetic field to transform energy from the circular relativistic electron beam to optical energy.

Molten metal removed from a workpiece in a laser cutting operation is blown away from the cutting point by a gas jet and collected on an electromagnet. The laser cutting is used to separate the castings of spent fuel rods from the fuel-containing elements therein.

A process is claimed for the production of substantial amounts of ethylene and other hydrocarbon compounds, such as benzene from coal. Coal is reacted with methane at a temperature in the approximate range of 500/sup 0/C to 1100/sup 0/C at a partial pressure less than about 200 psig for a period of less than 10 seconds, and preferably at a temperature of approximately 850/sup 0/C, and a partial pressure of 50 psig for a period of approximately 2 seconds. Ethylene and other hydrocarbon compounds may be separated from the product stream so produced, and the methane recycled for further production of ethylene. In another embodiment, other compounds produced, such as by-product tars, may be burned to heat the recycled methane.

The invention is a tomograph modified to be in a clamshell configuration so that the ring or rings may be moved to multiple sampling positions. The tomograph includes an array of detectors arranged in successive adjacent relative locations along a closed curve in a first position in a selected plane, and means for securing the detectors in the relative locations in a first sampling position. The securing means is movable in the plane in two sections and pivotable at one point and only one point to enable movement of at least one of the sections to a second sampling position out of the closed curve so that the ends of the section which are opposite the point are moved apart a predetermined space.

A method is described for the preparation of defined, isomerically pure phospholipid-nucleoside conjugates as a prodrug in which the drug (araC) is attached to the phospholipid by a monophosphate linkage. Key intermediates in the process involve selective blocking and deblocking of the nucleoside derivative. These particular monophosphate-linked derivatives represent a new class of prodrug, which are useful by themselves or in combination with diphosphate linked derivatives. Several new compositions involving diphosphate linked derivatives are described in which the products are isomerically pure and having defined fatty acid chain lengths.

A method and apparatus are disclosed for removing airborne contaminants entrained in a gas or airstream. The apparatus includes an electric filter characterized by a movable endless belt electrode, a grounded electrode, and a filter medium sandwiched therebetween. Inclusion of the movable, endless belt electrode provides the driving force for advancing the filter medium through the filter, and reduces frictional drag on the filter medium, thereby permitting a wide choice of filter medium materials. Additionally, the belt electrode includes a plurality of pleats in order to provide maximum surface area on which to collect airborne contaminants.

High contrast silhouette images of a substantially opaque object are obtained using front illumination techniques. The object is frontally illuminated by light of a first polarization. A frontal surface of the object reflects the incident light to an observation station. The polarization of incident light bypassing the object and incident on a background is changed. The background light is reflected to the observation station, and the intensity of one of the two, differently polarized, reflected images is substantially reduced with respect to the other. Apparatus for carrying out the method includes a first polarizer for polarizing frontally incident illuminating light, a second polarizer behind the object and a reflective surface behind the second polarizer. A polarization analyzer, located in front of the object, is used to extinguish one of the two reflected images. Apparatus for carrying out the invention in instruments having a polarized light source and a polarization analyzer includes a combination of a polarizing material, for contacting a rear surface of the object, and a reflective surface provided adjacent the rear surface of the polarizing material. The combination is applied to the rear surface of the object. Back-surface mirrors of pleochroic substrates, applied to thin film physical vapor-deposited …

The photosensitivity of lead lanthanum zirconate titanate (PLZT) ceramic material used in high resolution, high contrast, and nonvolatile photoferroelectric image storage and display devices is enhanced significantly by positive ion implantation of the PLZT near its surface. Implanted ions include H/sup +/, He/sup +/, Ne/sup +/, Ar/sup +/, as well as chemically reactive ions from Fe, Cr, and Al. The positive ion implantation advantageously serves to shift the absorption characteristics of the PLZT material from near-uv light to visible light. As a result, photosensitivity enhancement is such that the positive ion implanted PLZT plate is sensitive even to sunlight and conventional room lighting, such as fluorescent and incandescent light sources. The method disclosed includes exposing the PLZT plate to the positive ions at sufficient density, from 1 x 10/sup 12/ to 1 x 10/sup 17/, and with sufficient energy, from 100 to 500 keV, to provide photosensitivity enhancement. The PLZT material may have a lanthanum content ranging from 5 to 10%, a lead zirconate content of 62 to 70 mole %, and a lead titanate content of 38 to 30%. The ions are implanted at a depth of 0.1 to 2 microns below the surface of the PLZT plate.

Improved means and process for producing ethanol by fermentation are provided. Another object of the invention is to produce ethanol in a continuous-flow process by means of a biological catalyst that can be retained in a continuous-flow reactor vessel without being bonded to or held within a support material. An additional object of the invention is to provide a fermentation reactor vessel wherein disturbance of the desirable plug flow of sugar solution is minimized. These objects are attained by the preferred apparatus and process of the invention which utilize a newly-discovered flocculent strain of Zymomonas mobilis for converting sugar to ethanol in a continuous flow-type reactor vessel. The flow rate of a sugar-containing solution through a column containing the floc-forming strain of Z. mobilis is adjusted so that a sufficient conversion of sugar to ethanol is achieved in the column and the flocculent Z. mobilis is not washed away in effluent from the column. Carbon dioxide gas generated by the fermentation process is vented from a plurality of points spaced along an inclined column in which the process is conducted, thus minimizing disturbance of the plug flow of liquid by this gas.

This invention provides simple, inexpensive, independent and passive, conducting loops for stabilizing a plasma ring having externally produced equilibrium fields on opposite sides of the plasma ring and internal plasma currents that interact to tilt and/or shift the plasma ring relative to the externally produced equilibrium field so as to produce unstable tilting and/or shifting modes in the plasma ring. More particularly this invention provides first and second passive conducting loops for containing first and second induced currents in first and second directions corresponding to the amplitude and directions of the unstable tilting and/or shifting modes in the plasma ring. To this end, the induced currents provide additional magnetic fields for producing restoring forces and/or restoring torques for counteracting the tilting and/or shifting modes when the conducting loops are held fixed in stationary positions relative to the externally produced equilibrium fields on opposite sides of the plasma ring.

A method of preparing a porous cathode structure for use in a molten carbonate fuel cell begins by providing a porous integral plaque of sintered nickel oxide particles. The nickel oxide plaque can be obtained by oxidizing a sintered plaque of nickel metal or by compacting and sintering finely divided nickel oxide particles to the desired pore structure. The porous sintered nickel oxide plaque is contacted with a lithium salt for a sufficient time to lithiate the nickel oxide structure and thus enhance its electronic conductivity. The lithiation can be carried out either within an operating fuel cell or prior to assembling the plaque as a cathode within the fuel cell.

A method for simultaneous amplification of laser beams with a sequence of freqeuncies in a single pass, using a relativistic beam of electrons grouped in a sequence of energies corresponding to the sequence of laser beam frequencies is described. The method allows electrons to pass from one potential well or bucket to another adjacent bucket, thus increasing efficiency of trapping and energy conversion.

A method for doping semiconductor material and the semiconductor produced by the method are described. An interface is established between a solid electrolyte and a semiconductor to be doped. The electrolyte is chosen to be an ionic conductor of the selected impurity and the semiconductor material and electrolyte are jointly chosen so that any compound formed from the impurity and the semiconductor will have a free energy no lower than the electrolyte. A potential is then established across the interface so as to allow the impurity ions to diffuse into the semiconductor. In one embodiment the semiconductor and electrolyte may be heated so as to increase the diffusion coefficient.

A bagging device for transferring material from a first chamber through an opening in a wall to a second chamber includes an outer housing communicating with the opening and having proximal and distal ends relative to the wall. An inner housing having proximal and distal ends corresponding to those of the outer housing is mounted in a concentrically spaced, sealed manner with respect to the distal end of the outer housing. The inner and outer housings and mounting means therebetween define an annular chamber, closed at its distal end and open at its proximal end, in which a pliable tube is slidably positioned in sealed engagement with the housings. The pliable tube includes a sealed end positioned adjacent the proximal end of the inner housing so as to maintain isolation between the first and second chambers. Displacement of the material to be bagged from the first chamber along the inner housing so as to contact the sealed portion of the pliable bag allows the material to be positioned within the pliable bag in the second chamber. The bag is then sealed and severed between where the material is positioned therein and the wall in providing a sealed container for handling …

Apparatus is described for detecting flaws in a tubular workpiece in a single scan. The coils of a dual coil bobbin eddy current inspection probe are wound at a 45/sup 0/ angle to the transverse axis of the probe, one coil having an angular position about the axis about 90/sup 0/ relative to the angular position of the other coil, and the angle of intersection of the planes containing the coils being about 60/sup 0/.

A bagging device for transferring material from a first chamber through an opening in a wall to a second chamber includes an outer housing communicating with the opening and having proximal and distal ends relative to the wall. An inner housing having proximal and distal ends corresponding to those of the outer housing is mounted in a concentrically spaced, sealed manner with respect to the distal end of the outer housing. The inner and outer housings and mounting means therebetween define an annular chamber, closed at its distal end and open at its proximal end, in which a pliable tube is slidably positioned in sealed engagement with the housings. The pliable tube includes a sealed end positioned adjacent the proximal end of the inner housing so as to maintain isolation between the first and second chambers. Displacement of the material to be bagged from the first chamber along the inner housing so as to contact the sealed portion of the pliable bag allows the material to be positioned within the pliable bag in the second chamber. The bag is then sealed and severed between where the material is positioned therein and the wall in providing a sealed container for handling …

An ultimate shutdown system is provided for termination of neutronic activity in a nuclear reactor. The shutdown system includes bead chains comprising spherical containers suspended on a flexible cable. The containers are comprised of mating hemispherical shells which provide a ruggedized enclosure for reactor poison material. The bead chains, normally suspended above the reactor core on storage spools, are released for downward travel upon command from an external reactor monitor. The chains are capable of horizontal movement, so as to flow around obstructions in the reactor during their downward motion.

A new composition of matter has been discovered which is an explosive addition compound of ammonium nitrate (AN) and diethylenetriamine trinitrate (DETN) in a 50:50 molar ratio. the compound is stable over extended periods of time only at temperatures higher than 46/sup 0/C, decomposing to a fine-grained eutectic mixture (which is also believed to be new) of AN and DETN at temperatures lower than 46/sup 0/C. The compound of the invention has an x-ray density of 1.61 g/cm/sup 3/, explodes to form essentially only gaseous products, has higher detonation properties (i.e., detonation velocity and pressure) than those of any mechanical mixture having the same density and composition as the compound of the invention, is a quite insensitive explosive material, can be cast at temperatures attainable by high pressure steam, and is prepared from inexpensive ingredients. Methods of preparing the compound and the fine-grained eutectic composition of the invention are given.

An improved spark gap apparatus is provided for precise switching of high currents from charged capacitors, and for protecting circuitry and circuit components, such as an energy storage capacitor, from overvoltage surges. The invention includes a pair of niobium electrodes with a melting point greater than 2000/sup 0/C that forms the spark gap. The electrodes are supported by conductive caps spaced apart from one another by an insulating member all of which form a hermetically sealed chamber filled with an inert, ionizable gas, preferably pure xenon. The spark gap device includes a quantity of solid radioactive stabilizer, carbon-14, placed within the hermetically sealed chamber adjacent to the spark gap. Methods for fabricating the device and its components are described. It is claimed that use of the Nb electrodes forestalls electrode erosion even under severe voltage and discharge conditions, that, by employing pure Xe gas, and solid carbon-14 radiation stabilizer, it is unnecessary to employ radioactive gases or chemically plated radioactive sources to promote ionization, and that, by selection of a suitable spark gap, a spark gap device is obtained which is capable of switching at 1700 V +- 10% for input voltage rates up to 570 V/ms and allowing peak …

An inertial trap and grooved impactor for providing a sharp cutoff for particles over 15 microns from entering an inhalable particulate sampler is disclosed. The impactor head has a tapered surface and is provided with V-shaped grooves. The tapered surface functions for reducing particle blow-off or reentrainment while the grooves prevent particle bounce. Water droplets and any resuspended material over the 15 micron size are collected by the inertial trap and deposited in a reservoir associated with the impactor.

A device is described for supporting a nuclear fuel rod in a fuel rod assembly which allows the rod to be removed without disturbing other rods in the assembly. A fuel rod cap connects the rod to a bolt which is supported in the assembly end fitting by means of a locking assembly. The device is designed so that the bolt is held securely during normal reactor operation yet may be easily disengaged and the fuel rod removed when desired.

This invention is directed to a process of generating silicon tetrafluoride (SiF/sub 4/) from aqueous solutions of hexafluorosilicic acid (H/sub 2/SiF/sub 6/), comprising reacting an aqueous solution of H/sub 2/SiF/sub 6/ with a concentrated aqueous salt solution to produce a precipitate, separating and drying the precipitate, and heating the precipitate in an inert atmosphere to decompose the precipitate producing SiF/sub 4/.