SELECTIVE REMOVAL OF STRONTIUM AND CESIUM FROM SIMULATED WASTE SOLUTION WITH TITANATE ION EXCHANGERS IN A FILTER CARTRIDGE CONFIGURATION (open access)

SELECTIVE REMOVAL OF STRONTIUM AND CESIUM FROM SIMULATED WASTE SOLUTION WITH TITANATE ION EXCHANGERS IN A FILTER CARTRIDGE CONFIGURATION

This report describes experimental results for the selective removal of strontium and cesium from simulated waste solutions using monosodium titanate (MST) and crystalline silicotitanate (CST)-laden filter cartridges. Four types of ion exchange cartridge media (CST and MST designed by both 3M and POROX{reg_sign}) were evaluated. In these proof-of-principle tests effective uptake of both Sr-85 and Cs-137 was observed. However, the experiments were not performed long enough to determine the saturation levels or breakthrough curve for each filter cartridge. POREX{reg_sign} MST cartridges, which by design were based on co-sintering of the active titanates with polyethylene particles, seem to perform as well as the 3M-designed MST cartridges (impregnated filter membrane design) in the uptake of strontium. At low salt simulant conditions (0.29 M Na{sup +}), the instantaneous decontamination factor (D{sub F}) for Sr-85 with the 3M-design MST cartridge measured 26, representing the removal of 96% of the Sr-85. On the other hand, the Sr-85 instantaneous D{sub F} with the POREX{reg_sign} design MST cartridge measured 40 or 98% removal of the Sr-85. Strontium removal with the 3M-design MST and CST cartridges placed in series filter arrangement produced an instantaneous decontamination factor of 41 or 97.6% removal compared to an instantaneous decontamination factor of …
Date: May 26, 2011
Creator: Oji, L.; Martin, K. & Hobbs, D.
Object Type: Report
System: The UNT Digital Library
Final Technical Report for DOE Grant, number DE-FG02-05ER15701; Probing Surface Chemistry Under Catalytic Conditions: Olefin Hydrogenation,Cyclization and Functionalization. (open access)

Final Technical Report for DOE Grant, number DE-FG02-05ER15701; Probing Surface Chemistry Under Catalytic Conditions: Olefin Hydrogenation,Cyclization and Functionalization.

The specific goal of this work was to understanding the catalytic reactions pathways for the synthesis of vinyl acetate over Pd, Au and PdAu alloys. A combination of both experimental methods (X-ray and Auger spectroscopies, low-energy ion scattering (LEIS), low-energy electron diffraction (LEED) and theory (Density Functional Theory (DFT) calculations and Monte Carlo methods under various different reactions) were used to track the surface chemistry and the influence of alloying. The surface intermediates involved in the various reactions were characterized using reflection-absorption infrared spectroscopy and LEED to identify the nature of the surface species and temperature-programmed desorption (TPD) to follow the decomposition pathways and measure heats of adsorption. These results along with those from density functional theoretical calculations were used determine the kinetics for elementary steps. The results from this work showed that the reaction proceeds via the Samanos mechanism over Pd surfaces whereby the ethylene directly couples with acetate to form an acetoxyethyl intermediate that subsequently undergoes a beta-hydride elimination to form the vinyl acetate monomer. The presence of Au was found to modify the adsorption energies and surface coverages of important surface intermediates including acetate, ethylidyne and ethylene which ultimately influences the critical C-H activation and coupling steps. …
Date: May 26, 2011
Creator: Neurock, Matthew
Object Type: Report
System: The UNT Digital Library
Plasma Mass Filters For Nuclear Waste Reprocessing (open access)

Plasma Mass Filters For Nuclear Waste Reprocessing

Practical disposal of nuclear waste requires high-throughput separation techniques. The most dangerous part of nuclear waste is the fission product, which contains the most active and mobile radioisotopes and produces most of the heat. We suggest that the fission products could be separated as a group from nuclear waste using plasma mass filters. Plasmabased processes are well suited to separating nuclear waste, because mass rather than chemical properties are used for separation. A single plasma stage can replace several stages of chemical separation, producing separate streams of bulk elements, fission products, and actinoids. The plasma mass filters may have lower cost and produce less auxiliary waste than chemical processing plants. Three rotating plasma configurations are considered that act as mass filters: the plasma centrifuge, the Ohkawa filter, and the asymmetric centrifugal trap.
Date: May 26, 2011
Creator: Fetterman, Abraham J. & Fisch, Nathaniel J.
Object Type: Report
System: The UNT Digital Library
BLENDING STUDY FOR SRR SALT DISPOSITION INTEGRATION: TANK 50H SCALE-MODELING AND COMPUTER-MODELING FOR BLENDING PUMP DESIGN, PHASE 2 (open access)

BLENDING STUDY FOR SRR SALT DISPOSITION INTEGRATION: TANK 50H SCALE-MODELING AND COMPUTER-MODELING FOR BLENDING PUMP DESIGN, PHASE 2

The Salt Disposition Integration (SDI) portfolio of projects provides the infrastructure within existing Liquid Waste facilities to support the startup and long term operation of the Salt Waste Processing Facility (SWPF). Within SDI, the Blend and Feed Project will equip existing waste tanks in the Tank Farms to serve as Blend Tanks where 300,000-800,000 gallons of salt solution will be blended in 1.3 million gallon tanks and qualified for use as feedstock for SWPF. Blending requires the miscible salt solutions from potentially multiple source tanks per batch to be well mixed without disturbing settled sludge solids that may be present in a Blend Tank. Disturbing solids may be problematic both from a feed quality perspective as well as from a process safety perspective where hydrogen release from the sludge is a potential flammability concern. To develop the necessary technical basis for the design and operation of blending equipment, Savannah River National Laboratory (SRNL) completed scaled blending and transfer pump tests and computational fluid dynamics (CFD) modeling. A 94 inch diameter pilot-scale blending tank, including tank internals such as the blending pump, transfer pump, removable cooling coils, and center column, were used in this research. The test tank represents a 1/10.85 …
Date: May 26, 2011
Creator: Leishear, R.; Poirier, M. & Fowley, M.
Object Type: Report
System: The UNT Digital Library
Massive-scale RDF Processing Using Compressed Bitmap Indexes (open access)

Massive-scale RDF Processing Using Compressed Bitmap Indexes

The Resource Description Framework (RDF) is a popular data model for representing linked data sets arising from the web, as well as large scienti#12;c data repositories such as UniProt. RDF data intrinsically represents a labeled and directed multi-graph. SPARQL is a query language for RDF that expresses subgraph pattern-#12;nding queries on this implicit multigraph in a SQL- like syntax. SPARQL queries generate complex intermediate join queries; to compute these joins e#14;ciently, we propose a new strategy based on bitmap indexes. We store the RDF data in column-oriented structures as compressed bitmaps along with two dictionaries. This paper makes three new contributions. (i) We present an e#14;cient parallel strategy for parsing the raw RDF data, building dictionaries of unique entities, and creating compressed bitmap indexes of the data. (ii) We utilize the constructed bitmap indexes to e#14;ciently answer SPARQL queries, simplifying the join evaluations. (iii) To quantify the performance impact of using bitmap indexes, we compare our approach to the state-of-the-art triple-store RDF-3X. We #12;nd that our bitmap index-based approach to answering queries is up to an order of magnitude faster for a variety of SPARQL queries, on gigascale RDF data sets.
Date: May 26, 2011
Creator: Madduri, Kamesh & Wu, Kesheng
Object Type: Article
System: The UNT Digital Library
Raman Spectroscopy of Lithium Hydride Corrosion: Selection of an Appropriate Excitation Wavelength to Minimize Fluorescence (open access)

Raman Spectroscopy of Lithium Hydride Corrosion: Selection of an Appropriate Excitation Wavelength to Minimize Fluorescence

The recent interest in a hydrogen-based fuel economy has renewed research into metal hydride chemistry. Many of these compounds react readily with water to release hydrogen gas and form a caustic. Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFT) has been used to study the hydrolysis reaction. The LiOH stretch appears at 3670 cm{sup -1}. Raman spectroscopy is a complementary technique that employs monochromatic excitation (laser) allowing access to the low energy region of the vibrational spectrum (<600 cm{sup -1}). Weak scattering and fluorescence typically prevent Raman from being used for many compounds. The role of Li{sub 2}O in the moisture reaction has not been fully studied for LiH. Li{sub 2}O can be observed by Raman while being hidden in the Infrared spectrum.
Date: May 26, 2011
Creator: Stowe, A. C. & Smyrl, N. R.
Object Type: Article
System: The UNT Digital Library
UNREVIEWED DISPOSAL QUESTION EVALUATION: CENTER SLIT TRENCHES ONE THROUGH FIVE OPERATIONAL COVERS REANALYSIS (open access)

UNREVIEWED DISPOSAL QUESTION EVALUATION: CENTER SLIT TRENCHES ONE THROUGH FIVE OPERATIONAL COVERS REANALYSIS

Operational inventory limits for the disposal of solid low-level waste in Slit Trenches 1-7 were established by the Special Analysis (SA) performed by Collard and Hamm (2008). To determine disposal limits for the Slit Trenches, the SA followed the methodology used in the 2008 PA (WSRC, 2008) which assumed that the inventories in each trench were instantaneously placed in 12/1995, which is the date when SLIT1 began operation. The 2008 SA analyzed the impact from placing storm-water runoff covers simultaneously over Slit Trenches 1-7 at 5, 10 and 15 years after the inventory was introduced. To include a measure of conservatism in the limits, the lowest of the limits calculated for any storm-water runoff cover placement time or that calculated in the original 2008 PA was chosen as the operational limit for each radionuclide. Through the availability of funding provided by the American Recovery and Reinvestment Act (ARRA), storm-water runoff covers were placed over Slit Trenches 1-5 in December 2010. SRNL was requested to perform a UDQE for this accelerated action. Table 1 below lists the operational dates for Slit Trenches 1-5 and the time elapsed between when the first waste package was disposed in each Slit Trench and when …
Date: May 26, 2011
Creator: Smith, F. & Swingle, R.
Object Type: Report
System: The UNT Digital Library
QUALIFICATION OF THE SAVANNAH RIVER SITE 252CF SHUFFLER FOR RECEIPT VERIFICATION MEASUREMENTS OF MIXED U-PU OXIDES STORED IN 9975 SHIPPING CONTAINERS (open access)

QUALIFICATION OF THE SAVANNAH RIVER SITE 252CF SHUFFLER FOR RECEIPT VERIFICATION MEASUREMENTS OF MIXED U-PU OXIDES STORED IN 9975 SHIPPING CONTAINERS

To extend their ability to perform accountability and verification measurements of {sup 235}U in a U-Pu oxide matrix, the K-Area Material Storage facility commissioned the development and construction of a Passive/Active {sup 252}Cf Shuffler. A series of {sup 252}Cf, PuO{sub 2}, and U-Pu oxide standards, in addition to a single U{sub 3}O{sub 8} standard, were measured to characterize and calibrate the shuffler. Accompanying these measurements were simulations using MCNP5/MCNPX, aimed at isolating the neutron countrate contributions for each of the isotopes present. Two calibration methods for determining the {sup 235}U content in mixed UPu oxide were then developed, yielding comparable results. The first determines the {sup 235}U mass by estimating the {sup 239}Pu/{sup 235}U ratio-dependent contributions from the primary delayed neutron contributors. The second defines an average linear response based on the {sup 235}U and {sup 239}Pu mass contents. In each case, it was observed that self-shielding due to {sup 235}U mass has a large influence on the observed rates, requiring bounds on the applicable limits of each calibration method.
Date: May 26, 2011
Creator: Dubose, F.
Object Type: Article
System: The UNT Digital Library
Molecular Assemblies, Genes and Genomics Integrated Efficiently (MAGGIE) (open access)

Molecular Assemblies, Genes and Genomics Integrated Efficiently (MAGGIE)

Final report on MAGGIE. We set ambitious goals to model the functions of individual organisms and their community from molecular to systems scale. These scientific goals are driving the development of sophisticated algorithms to analyze large amounts of experimental measurements made using high throughput technologies to explain and predict how the environment influences biological function at multiple scales and how the microbial systems in turn modify the environment. By experimentally evaluating predictions made using these models we will test the degree to which our quantitative multiscale understanding wilt help to rationally steer individual microbes and their communities towards specific tasks. Towards this end we have made substantial progress towards understanding evolution of gene families, transcriptional structures, detailed structures of keystone molecular assemblies (proteins and complexes), protein interactions, biological networks, microbial interactions, and community structure. Using comparative analysis we have tracked the evolutionary history of gene functions to understand how novel functions evolve. One level up, we have used proteomics data, high-resolution genome tiling microarrays, and 5' RNA sequencing to revise genome annotations, discover new genes including ncRNAs, and map dynamically changing operon structures of five model organisms: For Desulfovibrio vulgaris Hildenborough, Pyrococcus furiosis, Sulfolobus solfataricus, Methanococcus maripaludis and Haiobacterium salinarum …
Date: May 26, 2011
Creator: Baliga, Nitin S.
Object Type: Report
System: The UNT Digital Library
Topological Cacti: Visualizing Contour-based Statistics (open access)

Topological Cacti: Visualizing Contour-based Statistics

Contours, the connected components of level sets, play an important role in understanding the global structure of a scalar field. In particular their nestingbehavior and topology-often represented in form of a contour tree-have been used extensively for visualization and analysis. However, traditional contour trees onlyencode structural properties like number of contours or the nesting of contours, but little quantitative information such as volume or other statistics. Here we use thesegmentation implied by a contour tree to compute a large number of per-contour (interval) based statistics of both the function defining the contour tree as well asother co-located functions. We introduce a new visual metaphor for contour trees, called topological cacti, that extends the traditional toporrery display of acontour tree to display additional quantitative information as width of the cactus trunk and length of its spikes. We apply the new technique to scalar fields ofvarying dimension and different measures to demonstrate the effectiveness of the approach.
Date: May 26, 2011
Creator: Weber, Gunther H.; Bremer, Peer-Timo & Pascucci, Valerio
Object Type: Book
System: The UNT Digital Library
Automatic Thread-Level Parallelization in the Chombo AMR Library (open access)

Automatic Thread-Level Parallelization in the Chombo AMR Library

The increasing on-chip parallelism has some substantial implications for HPC applications. Currently, hybrid programming models (typically MPI+OpenMP) are employed for mapping software to the hardware in order to leverage the hardware?s architectural features. In this paper, we present an approach that automatically introduces thread level parallelism into Chombo, a parallel adaptive mesh refinement framework for finite difference type PDE solvers. In Chombo, core algorithms are specified in the ChomboFortran, a macro language extension to F77 that is part of the Chombo framework. This domain-specific language forms an already used target language for an automatic migration of the large number of existing algorithms into a hybrid MPI+OpenMP implementation. It also provides access to the auto-tuning methodology that enables tuning certain aspects of an algorithm to hardware characteristics. Performance measurements are presented for a few of the most relevant kernels with respect to a specific application benchmark using this technique as well as benchmark results for the entire application. The kernel benchmarks show that, using auto-tuning, up to a factor of 11 in performance was gained with 4 threads with respect to the serial reference implementation.
Date: May 26, 2011
Creator: Christen, Matthias; Keen, Noel; Ligocki, Terry; Oliker, Leonid; Shalf, John; Van Straalen, Brian et al.
Object Type: Report
System: The UNT Digital Library
Post-Closure Inspection Letter Report for Corrective Action Units on the Nevada National Security Site (open access)

Post-Closure Inspection Letter Report for Corrective Action Units on the Nevada National Security Site

This letter serves as the post-closure inspection letter report for corrective action units on the Nevada National Security Site for calendar year 2011. Copies of completed inspection checklists are included in this report.
Date: May 26, 2011
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Monitoring Spent or Reprocessed Nuclear Fuel Using Fast Neutrons (open access)

Monitoring Spent or Reprocessed Nuclear Fuel Using Fast Neutrons

None
Date: May 26, 2011
Creator: Chapline, G F; Nakae, L F; Snyderman, N; Verbeke, J M & Wurtz, R
Object Type: Article
System: The UNT Digital Library