High temperature properties of sodium, potassium, and cesium thirteenth progress report

Thermophysical properties of sodium, potassium, and cesium at high temperatures - density of liquid potassium and vapor pressure of cesiu

Rapid sea level rise in the aftermath of a Neoproterozoic snowball Earth

Earth’s most severe climate changes occurred during global-scale “snowball Earth” glaciations, which profoundly altered the planet’s atmosphere, oceans, and biosphere. Extreme rates of glacioeustatic sea level rise are predicted by the snowball Earth hypothesis, but supporting geologic evidence has been lacking. We use paleohydraulic analysis of wave ripples and tidal laminae in the Elatina Formation, Australia—deposited after the Marinoan glaciation ~635 million years ago—to show that water depths of 9 to 16 meters remained nearly constant for ~100 years throughout 27 meters of sediment accumulation. This accumulation rate was too great to have been accommodated by subsidence and instead indicates an extraordinarily rapid rate of sea level rise (0.2 to 0.27 meters per year). Our results substantiate a fundamental prediction of snowball Earth models of rapid deglaciation during the early transition to a supergreenhouse climate

Brayton-cycle radioisotope heat-source design study. Phase II /preliminary design/ report

Brayton cycle radioisotope heat source desig

Improving Phrap-Based Assembly of the Rat Using “Reliable” Overlaps

The assembly methods used for whole-genome shotgun (WGS) data have a major impact on the quality of resulting draft genomes. We present a novel algorithm to generate a set of “reliable” overlaps based on identifying repeat k-mers. To demonstrate the benefits of using reliable overlaps, we have created a version of the Phrap assembly program that uses only overlaps from a specific list. We call this version PhrapUMD. Integrating PhrapUMD and our “reliable-overlap” algorithm with the Baylor College of Medicine assembler, Atlas, we assemble the BACs from the Rattus norvegicus genome project. Starting with the same data as the Nov. 2002 Atlas assembly, we compare our results and the Atlas assembly to the 4.3 Mb of rat sequence in the 21 BACs that have been finished. Our version of the draft assembly of the 21 BACs increases the coverage of finished sequence from 93.4% to 96.3%, while simultaneously reducing the base error rate from 4.5 to 1.1 errors per 10,000 bases. There are a number of ways of assessing the relative merits of assemblies when the finished sequence is available. If one views the overall quality of an assembly as proportional to the inverse of the product of the error rate and sequence missed, then the assembly presented here is seven times better. The UMD Overlapper with options for reliable overlaps is available from the authors at http://www.genome.umd.edu. We also provide the changes to the Phrap source code enabling it to use only the reliable overlaps

Nano-porosity in GaSb induced by swift heavy ion irradiation

Nano-porous structures form in GaSb after ion irradiation with 185 MeV Au ions. The porous layer formation is governed by the dominant electronic energy loss at this energy regime. The porous layer morphology differs significantly from that previously reported for low-energy, ion-irradiated GaSb. Prior to the onset of porosity, positron annihilation lifetime spectroscopy indicates the formation of small vacancy clusters in single ion impacts, while transmission electron microscopy reveals fragmentation of the GaSb into nanocrystallites embedded in an amorphous matrix. Following this fragmentation process, macroscopic porosity forms, presumably within the amorphous phase.The authors thank the Australian Research Council for support and the staff at the ANU Heavy Ion Accelerator Facility for their continued technical assistance. R.C.E. acknowledges the support from the Office of Basic Energy Sciences of the U.S. DOE (Grant No. DE-FG02-97ER45656)

Brayton-cycle radioisotope heat source design study. Phase I - /Conceptual design/ report

Conceptual designs for radioisotope heat source systems to provide 25 kW thermal power to Brayton cycle power conversion system for space application

Radio Astronomy

Contains reports on three research projects.National Aeronautics and Space Administration (Grant NGL 22-009-016)National Science Foundation (Grant GP-8415)Joint Services Electronics Programs (U. S. Army, U.S. Navy, and U. S. Air Force) under Contract DA 28-043-AMC-02536(E

Consolidation of Geologic Studies of Geopressured-Geothermal Resources in Texas

Two major structural styles are identified in the Wilcox growth-fault trend of the Texas Gulf Coast. The style in central and southeast Texas is characterized by continuous, closely spaced growth faults that have little associated rollover despite moderate expansion of section and that show little flattening of the fault plane with depth. Where the growth-fault trend crosses the Houston Diapir Province, growth faults are localized by preexisting salt pillows; however, the piercement salt domes formed after the main phase of faulting, so the salt tectonics "overprints" the growth faults. In South Texas (south of Live Oak County), a narrow band of growth faults having high expansion and moderate rollover lies over and downdip of a ridge of deformed, overpressured shale and lies updip of a deep Tertiary-filled basin formed by withdrawal of overpressured shale. Significant antithetic faulting is associated with this band of growth faults. Also in South Texas, the lower Wilcox Lobo trend is deformed by highly listric normal faults beneath an unconformity that is probably related to Laramide tectonic activity. Wilcox sandstone reservoirs are predominantly of high-constructive deltaic (distributary-channel and delta-front) origin. This, together with close spacing of faults and characteristically low permeabilities, limits the size of geopressured reservoirs. The largest reservoirs may be in interfault areas or in salt- or shale-withdrawal basins.Bureau of Economic Geolog