Multiscale analysis of nonlinear systems using computational homology (open access)

Multiscale analysis of nonlinear systems using computational homology

This is a collaborative project between the principal investigators. However, as is to be expected, different PIs have greater focus on different aspects of the project. This report lists these major directions of research which were pursued during the funding period: (1) Computational Homology in Fluids - For the computational homology effort in thermal convection, the focus of the work during the first two years of the funding period included: (1) A clear demonstration that homology can sensitively detect the presence or absence of an important flow symmetry, (2) An investigation of homology as a probe for flow dynamics, and (3) The construction of a new convection apparatus for probing the effects of large-aspect-ratio. (2) Computational Homology in Cardiac Dynamics - We have initiated an effort to test the use of homology in characterizing data from both laboratory experiments and numerical simulations of arrhythmia in the heart. Recently, the use of high speed, high sensitivity digital imaging in conjunction with voltage sensitive fluorescent dyes has enabled researchers to visualize electrical activity on the surface of cardiac tissue, both in vitro and in vivo. (3) Magnetohydrodynamics - A new research direction is to use computational homology to analyze results of large …
Date: May 24, 2010
Creator: Mischaikow, Konstantin; Schatz, Michael; Kalies, William & Wanner, Thomas
Object Type: Report
System: The UNT Digital Library
21st Century Locomotive Technology: Quarterly Technical Status Report 29 (open access)

21st Century Locomotive Technology: Quarterly Technical Status Report 29

Hybrid trip optimizer analysis tool has been implemented, to determine the optimal driving and hybrid charge-discharge control for a train.
Date: May 24, 2010
Creator: Lembit Salasoo, Ramu Chandra
Object Type: Report
System: The UNT Digital Library
Assessment of the Potential for Hydrogen Generation During Grouting Operations in the R and P Reactor Vessels (open access)

Assessment of the Potential for Hydrogen Generation During Grouting Operations in the R and P Reactor Vessels

The R- and P-reactor buildings were retired from service and are now being prepared for deactivation and decommissioning (D and D). D and D activities consist primarily of immobilizing contaminated components and structures in a grout-like formulation. Aluminum corrodes very rapidly when it comes in contact with the alkaline grout materials and as a result produces hydrogen gas. To address this potential deflagration/explosion hazard, the Materials Science and Technology Directorate (MS and T) of the Savannah River National Laboratory (SRNL) has been requested to review and evaluate existing experimental and analytical studies of this issue to determine if any process constraints on the chemistry of the fill material and the fill operation are necessary. Various options exist for the type of grout material that may be used for D and D of the reactor vessels. The grout formulation options include ceramicrete (pH 6-8), low pH portland cement + silica fume grout (pH 10.4), or Portland cement groupt (pH 12.5). The assessment concluded that either ceramicrete or the silica fume grout may be used to safely grout the P-reactor vessel. The risk of accumulation of a flammable mixture of hydrogen between the grout-air interface and the top of the reactor is …
Date: May 24, 2010
Creator: Wiersma, B.
Object Type: Report
System: The UNT Digital Library
Long Range Active Detection of HEU Based on Thermal Neutron Multiplication (open access)

Long Range Active Detection of HEU Based on Thermal Neutron Multiplication

We report on the results of measurements of proton irradiation on a series of targets at Brookhaven National Laboratory’s (BNL) Alternate Gradient Synchrotron Facility (AGS), in collaboration with LANL and SNL. We examined the prompt radiation environment in the tunnel for the DTRA-sponsored series (E 972), which investigated the penetration of air and subsequent target interaction of 4 GeV proton pulses. Measurements were made by means of an organic scintillator with a 500 MHz bandwidth system. We found that irradiation of a depleted uranium (DU) target resulted in a large gamma-ray signal in the 100-500 µsec time region after the proton flash when the DU was surrounded by polyethylene, but little signal was generated if it was surrounded by boron-loaded polyethylene. Subsequent Monte Carlo (MCNPX) calculations indicated that the source of the signal was consistent with thermal neutron capture in DU. The MCNPX calculations also indicated that if one were to perform the same experiment with a highly enriched uranium (HEU) target there would be a distinctive fast neutron yield in this 100-500 µsec time region from thermal neutron-induced fission. The fast neutrons can be recorded by the same direct current system and differentiated from gamma ray pulses in organic …
Date: May 24, 2010
Creator: L., Forman; I., Dioszegi; Salwen, C. & and Vanier, P.E.
Object Type: Article
System: The UNT Digital Library
INDEPENDENT VERIFICATION SURVEY REPORT FOR THE OPERABLE UNIT-1 LANDFILL TRENCHES, MIAMISBURG CLOSURE PROJECT (open access)

INDEPENDENT VERIFICATION SURVEY REPORT FOR THE OPERABLE UNIT-1 LANDFILL TRENCHES, MIAMISBURG CLOSURE PROJECT

INDEPENDENT VERIFICATION SURVEY REPORT FOR THE OPERABLE UNIT-1 LANDFILL TRENCHES, MIAMISBURG CLOSURE PROJECT, MIAMISBURG, OHIO DCN: 0468-SR-02-0
Date: May 24, 2010
Creator: Adams, W. C.
Object Type: Report
System: The UNT Digital Library
Distribution of Te inclusions in a CdZnTe wafer and their effects on the electrical properties of fabricated devices (open access)

Distribution of Te inclusions in a CdZnTe wafer and their effects on the electrical properties of fabricated devices

We quantified the size and concentration of Te-inclusions along the lateral- and the growth-directions of a {approx}6 mm thick wafer cut axially along the center of a CdZnTe ingot. We fabricated devices, selecting samples from the center slice outward in both directions, and then tested their response to incident x-rays. We employed, in concert, an automated IR transmission microscopic system and a highly collimated synchrotron X-ray source that allowed us to acquire and correlate comprehensive information on Te inclusions and other defects to assess the material factors limiting the performance of CdZnTe detectors.
Date: May 24, 2010
Creator: Hossain , A.; Xu, L.; Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; Yang, G. et al.
Object Type: Article
System: The UNT Digital Library
Local Magnitude Tomography in California (open access)

Local Magnitude Tomography in California

None
Date: May 24, 2010
Creator: Ford, S R; Uhrhammer, R A & Hellweg, M
Object Type: Article
System: The UNT Digital Library