A KMS laser experiment collides Aluminum (A1) and Magnesium (Mg) plasmas. The measurements include electron density, time and space resolved Ly-alpha and He-alpha lines of Al and Mg, and x-ray images. These measurements were analyzed with a hydrodynamic code, LASNEX, and a special two-fluid code OFIS. The results strongly suggest that at early times, the Al interpenetrates the counterstreaming Mg and deposits in the dense Mg region. At late times, the Al plasma stagnates against the Mg plasma.

The structural characteristics of (111) twist boundaries in gold are investigated using a combination of x-ray diffraction and computer modeling techniques. Comparison of the measured scattering effects with those generated from EAM computer models reveals that the (111) boundary displacement field is weak, rotational in form and centered on O' lattice sites. Furthermore, the measured intensities of the strong O' lattice reflections decrease smoothly with increasing boundary angle up to 30{degree}, as calculated from the model. The effect of double positioning on the diffraction pattern and the structural analysis is discussed. 9 refs., 2 figs.

Research continued on catalysts of coal liquefaction. Estimates of liquid circulation rates were obtained from an analysis of the cold model data and a plot of these values versus stirrer speed appears to be unique for the 60{degree} axial impeller. The recycle ration is typically of the order of 1000/1 or greater, and for all practical purposes the reactor may be treated as a perfectly mixed reactor. The work up of hydrotreating Run PDJ03 is complete. The run was terminated prematurely due to a rupture disk failure, but eight of the ten planned balance periods were completed. Carbon material balances were slightly high, ranging from 100.7% to 106.7%. Reaction rates for hydrogen uptake, hydrodesulfurization and hydrodenitrogenation were calculated. The catalyst did not deactivate significantly for the duration of the run and no evidence of catalyst attrition was observed after 215 hours of service. 8 refs., 4 figs., 2 tabs.

OAK B188 Response of Tundra Ecosystems to Elevated Atmospheric CO{sub 2}. Atmospheric CO{sub 2} is expected to double by the end of the next century. Global mean increases in surface air temperature of 1.5-4.5 C are anticipated with larger increases towards the poles predicted. Changes in CO{sub 2} levels and temperature could have major impacts on ecosystem functioning, including primary productivity, species composition, plant-animal interactions, and carbon storage. Until recently, there has been little direct information on the impact of changes in CO{sub 2} and temperature on native ecosystems. The study described here was undertaken to evaluate the effects of a 50 and 100% increase in atmospheric CO{sub 2}, and a 100% increase in atmospheric CO{sub 2} coupled with a 4 C summer air temperature rise on the structure and function of an arctic tussock tundra ecosystem. The arctic contains large stores of carbon as soil organic matter, much frozen in permafrost and currently not reactive or available for oxidation and release into the atmosphere. About 10-27% of the world's terrestrial carbon occurs in arctic and boreal regions, and carbon is accumulating in these regions at the rate of 0.19 GT y{sup -1}. Mean temperature increases of 11 C and …

OAK (B204) Response of Tundra Ecosystems to Elevated Atmospheric CO{sub 2} Part 3 of 3.

Newsletter of the Texas Bureau of Disease Control and Epidemiology discussing the news, activities, and events of the organization and other information related to health in Texas.