A major milestone was completed in the Oceans Engineering area with the successful deployment of the Test Farm. All systems were installed by 29 September 1978, and a detailed systems checkout is now underway prior to a full start-up of the Test Farm. Compatibility of the Test Farm with the planned transport and attachment procedures of the Macrocystis pyrifera plants has been completed and planting will begin on the full structure during the month of October. Success was also achieved in the Inoculum Development phase of the program with the production of two methane enrichments, one grown on an acetate medium and the other on a mixed acid substrate. These will be used in future mixed inoculum digester studies as an attempt to significantly decrease detention time.

Topping cycles could boost the energy efficiencies of a variety of systems by using what is now waste heat. One such topping cycle uses a ceramic helical expander and would require that a reaction-bonded silicon nitride (RBSN) rotor be bonded to a shaft of TZM (Mo-0.5 wt % Ti-0.08 wt % Zr). Coupon studies show that TZM can be bonded to RBSN at 1300/sup 0/C and 69 MPa if there is an interlayer of MoSi/sub 2/. A layer of finely ground (10 ..mu..m) MoSi/sub 2/ facilitates bond formation and provides a thicker bond interface. The hardness and grain structure of the TZM and RBSN were not affected by the temperature and pressure required to bond the coupons.

A research program to investigate the technical and economic feasibility of producing solar-cell-quality sheet silicon by coating inexpensive ceramic substrates with a thin layer of polycrystalline silicon is described. The coating methods to be developed are directed toward a minimum-cost process for producing solar cells with a terrestrial conversion efficiency of 12 percent or greater. By applying a graphite coating to one face of a ceramic substrate, molten silicon can be caused to wet only that graphite-coated face and produce uniform thin layers of large-grain polycrystalline silicon; thus, only a minimal quantity of silicon is consumed. A dip-coating method for putting silicon on ceramic (SOC) has been shown to produce solar-cell-quality sheet silicon. This method and a continuous coating process also being investigated have excellent scale-up potential which offers an outstanding cost-effective way to manufacture large-area solar cells. A variety of ceramic materials have been dip-coated with silicon. The investigation has shown that mullite substrates containing an excess of SiO/sub 2/ best match the thermal expansion coefficient of silicon and hence produce the best SOC layers. With such substrates, smooth and uniform silicon layers 25 cm/sup 2/ in area have been achieved with single-crystal grains as large as 4 mm …

The effectiveness of quadrupole vs. solenoidal focusing in suppressing the image displacement instability in linear induction electron accelerators is discussed. A brief explanation of the instability is presented; a criterion is derived for the magnitude of the solenoidal magnetic field required to suppress the instability. Two quadrupole arrangements are treated, and criteria derived for the magnitude of the pole-face field required to suppress the instability. For one arrangement the required pole-face field is less than one-half the required solenoidal field, suggesting that quadrupole focusing may have a practical advantage.

The objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the affect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered includes the activities associated with the procurement of the materials for the screening test program and information from vendor certification for the materials received for the nuclear process heat candidate alloys. The design modifications to the helium purification system and the construction status of the simulated reactor helium supply system, testing equipment, and analysis instrumentation and equipment are discussed. Finally, the status and details of the data management are presented.

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A nondestructive technique, using penetrating x radiation, has been developed to measure the density uniformity of low-Z, compressible materials that is independent of material thickness. Thickness independence is achieved by simultaneously monitoring the transmitted and scattered x rays. Results on samples of pressed carbon materials have demonstrated that there is the expected linear relationship between measured quantities and material density, independent of material thickness, and that this is a viable means of measuring density uniformity.

Dissolution parameters (in various reagents) of americium-241 and plutonium-239 oxide mixtures, uranium-233 oxide, neptunium-237 oxide, curium-244, thorium-232 oxide, and plutonium dioxide were determined. The reagents used were various concentrations of NHO/sub 3/-HF-H/sub 2/SO/sub 4/,HNO/sub 3/-(NH/sub 4/)/sub 2/Ce(NO/sub 3/)/sub 6/, HNO/sub 3/-HF, and HNO/sub 3/. Both simulated contaminated HEPA filter media and actual glovebox filter media from spent filters were used. The maximum decontamination factor achieved was 833 using a six-stage dissolution process. Also, plutonium dioxide was fused with sodium carbonate at various elevated temperatures, and a dissolution percentage was determined.

All the data reported previously have been reevaluated to determine the quantitative reaction network for dibenzothiophene hydrodesulfurization at about 100 atm and 300/sup 0/C. This network shows the high selectivity of the catalyst for simple hydrodesulfurization (biphenyl + H/sub 2/S formation). When methyl groups are present in the 4 and 6 positions of dibenzothiophene, the primary hydrogenation reaction is approximately as fast as the primary hydrodesulfurization reaction. Ni and Mo or Ni and W used instead of Co and Mo in the catalyst, or H/sub 2/S in the reactant mixture, also favor hydrogenation relative to hydrodesulfurization. Previous results have been evaluated in light of the recent literature to provide a new interpretation of the reaction mechanism of catalytic hydrodesulfurization on surfaces of sulfided Co-Mo/Al/sub 2/0/sub 3/. It has often been assumed that catalytic hydrodesulfurization of thiophene and related compounds proceeds via a one-point end-on adsorption involving bonding of the sulfur atom with Mo ions at an anion vacancy on the catalyst surface. This interpretation is inadequate, failing to account for deuterium-exchange results, the reactivities of benzothiophene and dibenzothiophene, and the small steric effects of methyl substituents affecting the adsorption and reaction of compounds in the thiophene, benzothiophene, and dibenzothiophene families …

Three high-pressure flow microreactors and two batch autoclave reactors have been used to study the reaction networks and kinetics of (1) catalytic hydrodesulfurization of dibenzothiophene and methyl-substituted dibenzothiophenes, and (2) catalytic hydrodenitrogenation of quinoline, methyl-substituted quinolines, acridine, benzacridines, dibenzacridine, and carbazole. The catalysts were commercial, sulfided CoO-MoO/sub 3//..gamma..-Al/sub 2/O/sub 3/, NiO-MoO/sub 3//..gamma..-Al/sub 2/O/sub 3/, and NiO-WO/sub 3//..gamma..-Al/sub 2/O/sub 3/. The results of the experiments are described. (LTN)

Three high-pressure flow microreactors and two batch autoclave reactors have been used to study the reaction networks and kinetics of: (1) catalytic hydrodesulfurization of dibenzothiophene and methyl-substituted dibenzothiophenes; and (2) catalytic hydrodenitrogenation of quinoline, methyl-substituted quinolines, acridine and carbazole. The catalysts were commercial, sulfided CoO-MoO/sub 3//..gamma..-Al/sub 2/O/sub 3/, NiO-MoO/sub 3//..gamma..-Al/sub 2/O/sub 3/, and NiO-WO/sub 3//..gamma..-Al/sub 2/O/sub 3/. At the typical conditions of 300/sup 0/C and 104 atm, dibenzothiophene reacts to give H/sub 2/S and biphenyl in high yield, but there is some hydrogenation preceding desulfurization. Methyl-substituted dibenzothiophenes react similarly, and each reaction is first-order in the sulfur-containing compound. Two methyl groups near the sulfur atom (in the 4 and 6 positions) reduce the reactivity tenfold, whereas methyl groups in positions further removed from the sulfur atom increase reactivity about twofold. The results are consistent with steric and inductive effects influencing adsorption. The data indicate competitive adsorption among the sulfur-containing compounds. In quinoline hydrodenitrogenation, both rings are saturated before the C-N bond is broken. Similarly, in acridine conversion a large amount of hydrogenation precedes nitrogen removal. Breaking of the carbon-nitrogen bond is evidently one of the slower reactions in the network. The Ni-Mo catalyst is about twice as active as the …

Load-deflection responses were determined experimentally for sixteen 152.4-mm (6-in.) (nominal) commercial carbon steel pipe elbows and four 152.4-mm (6-in.) stainless steel elbows. Each specimen was loaded with an external force of sufficient magnitude to produce predominantly plastic response. The influences of bend radius and wall thickness were studied, as well as the effect of internal prssure on load-deflection behavior. Comparisons of results from stainless steel and from carbon steel elbows indicate differences in responses attributable to material differences. The results were interpreted in terms of limit analysis concepts, and collapse loads were determined. Trends given by the collapse loads are identified and discussed.

Progress is reported in the design of the 50 MT/year experimental facility for the preparation of high-purity silicon by the zinc vapor reduction of silicon tetrachloride in a fluidized bed of seed particles to form a free-flowing granular product. Progress is reported in the design of the silicon tetrachloride purification facility, the zinc/ZnCl/sub 2/ by-product condenser and also non-conventional items, the fluidized bed, zinc feed system, zinc vaporizer, and electrolytic cell.