Engineering topics

Hollingsworth, Anthony

Publications and source records attributed to Hollingsworth, Anthony.

3 records

DOE OSTI2024

Distribution of Tritium in the Near Surface of Candidate Structural Materials for Fusion Reactors. Type 304L Stainless Steel, Inconel, Hastelloy, Eurofer-97, Oxide Dispersion-Strengthened Alloy 14YWT

Five different candidate structural materials for fusion have undergone pure tritium gas soaking at room temperature and at 310-mbar(a) pressure. The tritium uptake on the surface and in the bulk of the alloys has been analyzed using surface leaching, chemical etching, and thermal desorption. The nickel-based alloys: Inconel-X-750 and Hastelloy-X, absorbed the least amount of total tritium compared with austenitic stainless steel AISI 304L, reduced activation ferritic-martensitic (RAFM) Eurofer-97, and advanced nanoferritic alloy 14YWT. Microstructural analyses using electron backscatter diffraction (EBSD) indicate that the number of grains and mean grain size is not a dominant factor in near surface tritium uptake. The quantity of iron dissolved in the surface oxide appears to be the major factor in encouraging tritium absorption.

O'Callaghan, James↗

NASA NTRS1994

ECMWF and SSM/I global surface wind speeds

Monthly mean 2.5 deg x 2.5 deg resolution 10-m height wind speeds from the Special Sensor Microwave/Imager (SSM/I) instrument and the European Centre for Medium-Range Weather Forecasts (ECMWF) forecast-analysis system are compared between 60 deg S and 60 deg N during 1988-91. The SSM/I data were uniformly processed while numerous changes were made to the ECMWF forecast-analysis system. The SSM/I measurements, which were compared with moored-buoy wind observations, were used as a reference dataset to evaluate the influence of the changes made to the ECMWF system upon the ECMWF surface wind speed over the ocean. A demonstrable yearly decrease of the difference between SSM/I and ECMWF wind speeds occurred in the 10 deg S-10 deg N region, including the 5 deg S-5 deg N zone of the Pacific Ocean, where nearly all of the variations occurred in the 160 deg E-160 deg W region. The apparent improvement of the ECMWF wind speed occurred at the same time as the yearly decrease of the equatorial Pacific SSM/I wind speed, which was associated with the natural transition from La Nina to El Nino conditions. In the 10 deg S-10 deg N tropical Atlantic, the ECMWF wind speed had a 4-yr trend, which was not expected nor was it duplicated with the SSM/I data. No yearly trend was found in the difference between SSM/I and ECMWF surface wind speeds in middle latitudes of the Northern and Southern Hemispheres. The magnitude of the differences between SSM/I and ECMWF was 0.4 m/s or 100% larger in the Northern than in the Southern Hemisphere extratropics. In two areas (Arabian Sea and North Atlantic Ocean) where ECMWF and SSM/I wind speeds were compared to ship measurements, the ship data had much better agreement with the ECMWF analyses compared to SSM/I data. In the 10 deg S-10 deg N area the difference between monthly standard deviations of the daily wind speeds dropped significantly from 1988 to 1989 but remained constant at about 30% for the remaining years.

Halpern, David↗

NASA NTRS1993

ECMWF and SSMI Global Surface Wind Speeds

Monthly mean, 2.5 deg - x 2.5 deg-resolution, 10-m height wind speeds from the Special Sensor Microwave Imager (SSMI) instrument and the European Center for Medium-Range Weather Forecasts (ECMWF) forecast-analysis system are compared between 60 deg S and 60 deg N during 1988-1991. The SSMI data were uniformly processed while numerous changes were made to the ECMWF forecast-analysis system. The SSMI measurements, which were compared with moored-buoy wind observations, were considered to be a reference data set to evaluate the influence of the changes made to the ECMWF system upon the ECMWF surface wind speed over the ocean. A demonstrable yearly decrease of the difference between SSMI and ECMWF wind speeds occurred in the 10 deg S - 10 deg N region, including the 5 deg S - 5 deg N zone of the Pacific Ocean, where nearly all of the variations occurred in the 160 deg E - 160 deg W region. The apparent improvement of the ECMWF wind speed occurred at the same time as the yearly decrease of the equatorial Pacific SSMI wind speed, which was associated with the natural transition from La Nina to El Nino conditions. In the 10 deg S - 10 deg N tropical Atlantic, the ECMWF wind speed had a 4-year trend, which was not expected nor was it duplicated with the SSMI data. No yearly trend was found in the difference between SSMI and ECMWF surface wind speeds in middle latitudes of the northern and southern hemispheres. The magnitude of the differences between SSMI and ECMWF was 0.4 m s^(-1) or 100 percent larger in the northern than in the southern hemisphere extratropics. In two areas (Arabian Sea and North Atlantic Ocean) where ECMWF and SSMI wind speeds were compared to ship measurements, the ship data had much better agreement with the ECMWF analyses compared to SSMI data. In the 10 deg S - 10 deg N area the difference between monthly standard deviations of the daily wind speeds dropped significantly from 1988 to 1989, but remained constant at about 30 percent for the remaining years. y.

Halpern, David↗