Liquids derived from coal contain relatively high amounts of oxygenated organic compounds, mainly in the form of phenols and furans that are deleterious to the stability and quality of these liquids as fuels. Hydrodeoxygenation (HDO) using Mo/W sulfide catalysts is a promising method to accomplish this removal, but our understanding of the reactions occurring on the catalyst surface during HDO is very limited. Rather than attempting to examine the complexities of real liquids and catalysts we have adopted an approach here using model systems amenable to surface-sensitive techniques that enable us to probe in detail the fundamental processes occurring during HDO at the surfaces of well-defined model catalysts. The results of this work may lead to the development of more efficient, selective and stable catalysts. Above a S/Mo ratio of about 0.5 ML, furan does not adsorb on sulfided Mo surfaces; as the sulfur coverage is lowered increasing amounts of furan can be adsorbed. Temperature-programmed reaction spectroscopy (TPRS) reveals that C-H, C-C and C-O bond scission occurs on these surfaces. Auger spectra show characteristic changes in the nature and amount of surface carbon. Comparisons with experiments carried out with CO, H{sub 2} and alkenes show that reaction pathways include -- …

A comparison study was made between a quartz tube non-porous packed bed reactor and a 40 Angstrom pore size porous VYCOR membrane reactor using two different methane coupling catalysts. Comparisons of reactor performance of the two reactors were made on the basis of amount of methane converted, C{sub 2} selectivities and the total C{sub 2} yields. Identical flow and temperature conditions were maintained for the two reactor systems for this study. These studies appear to indicate that improved performance can be obtained in VYCOR membrane reactors. The product stream from the tube side effluent of the porous VYCOR membrane reactor was superior to that from the quartz tube non-porous reactor in terms of improved C{sub 2} selectivity. At the present stage of research, the total effluent from the membrane reactor compared slightly less favorably to the effluent from a non-porous reactor, but studies are continuing on devising a reactor configuration which increases methane throughput in the tube side of the membrane reactor which is expected to demonstrate the overall superiority of the membrane reactor. Simulation results obtained by doing a parameter study for different reactor systems showed that, for the methane coupling reaction, where the desired product formation had a …

In researching the theory of RBE, attention is focused on several topics of importance. They include: improving knowledge of the radial distribution of dose about the path of an energetic heavy ion in different media; calculations which have demonstrated that three Escherichia coli mutants behave as 1-hit detectors; lethal mutations in a nematode induced by gamma radiation and heavy ion beams; prevalence in cancer induction in the Harderian gland by HZE particles; subtleties in the analysis of radiobiological data; low-dose irradiation effects; high LET effects; cellular radiosensitivity parameters; and radial dose calculations for mammalian cells.

This report contains brief papers on the research being conducted at the Institute of Geophysics and Planetary Physics in 1993 in Geosciences, High-Pressure sciences, and Astrophysics.

The front end beamline section contains photon shutters and fixed masks. These components are made of OFHC copper and GlidCOP AL-15. Stainless steels (304 or 316) are also used for connecting photon shutters and fixed masks to other components that operate in the ultrahigh vacuum system. All these dissimilar materials need to be joined together. However, bonding these dissimilar materials is very difficult because of their different mechanical and thermal properties and incompatible metallurgical properties. Explosion bonding is a bonding method in which the controlled energy of a detonating explosive is used to create a metallurgical bond between two or more similar or dissimilar materials. No intermediate filler metal, for example, a brazing compound or soldering alloy, is needed to promote bonding, and no external heat need be applied. A study of the metallurgical and mechanical properties and YGV applications of GlidCop AL-15, OFHC copper, and 304 stainless steel explosion-bonded joints has been done. This report contains five parts: an ultrasonic examination of explosion-bonded joints and a standard setup; mechanical-property and thermal-cycle tests of GlidCop AL-15/304 stainless steel explosion-bonded joints; leak tests of a GlidCop AL-15/304 stainless steel explosion-bonded interfaces for UHV application; metallurgical examination of explosion-bonded interfaces and failure …

It has been suggested recently that most-favored-nation (MFN) status be extended to China permanently by determining that it is no longer a nonmarket economy (NME) country and thus removing China from the purview of the freedom-of-emigration waiver of the Jackson-Vanik amendment, required for the annual renewal of the MFN status of NME countries.