300 Area D4 Project Fiscal Year 2007 Building Completion Report (open access)

300 Area D4 Project Fiscal Year 2007 Building Completion Report

This report documents the deactivation, decontamination, decommissioning, and demolition (D4) of twenty buildings in the 300 Area of the Hanford Site. The D4 of these facilties included characterization, engineering, removal of hazardous and radiologically contaminated materials, equipment removal, utility disconnection, deactivation, decontamination, demolition of the structure, and stabilization or removal of the remaining slab and foundation, as appropriate.
Date: January 15, 2009
Creator: Westberg, R. A.
Object Type: Report
System: The UNT Digital Library
300 Area D4 Project Fiscal Year 2008 Building Completion Report (open access)

300 Area D4 Project Fiscal Year 2008 Building Completion Report

This report documents the deactivation, decontamination, decommissioning, and demolition (D4) of eighteen buildings in the 300 Area of the Hanford Site that were demolished in Fiscal Year 2008. The D4 of these facilties included characterization, engineering, removal of hazardous and radiologically contaminated materials, equipment removal, utility disconnection, deactivation, decontamination, demolition of the structure, and stabilization or removal of the remaining slab and foundation, as appropriate.
Date: January 15, 2009
Creator: Westberg, R. A.
Object Type: Report
System: The UNT Digital Library
ACRF Instrumentation Status: New, Current, and Future - December 2008 (open access)

ACRF Instrumentation Status: New, Current, and Future - December 2008

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.
Date: January 15, 2009
Creator: Voyles, J. W.
Object Type: Report
System: The UNT Digital Library
Alloys for 1000 degree C service in the Next Generation Nuclear Plant NERI 05-0191 (open access)

Alloys for 1000 degree C service in the Next Generation Nuclear Plant NERI 05-0191

The objective of the proposed research is to define strategies for the improvement of alloys for structural components, such as the intermediate heat exchanger and primary-to-secondary piping, for service at 1000 degree C in the He environment of the NGNP. Specifically, we will investigate the oxidation/carburization behavior and microstructure stability and how these processes affect creep. While generating this data, the project will also develop a fundamental understanding of how impurities in the He environment affect these degradation processes and how this understanding can be used to develop more useful life prediction methodologies.
Date: January 15, 2009
Creator: Was, Gary S.; Jones, J.W. & Pollock, T.
Object Type: Report
System: The UNT Digital Library
AmiGO: online access to ontology and annotation data (open access)

AmiGO: online access to ontology and annotation data

AmiGO is a web application that allows users to query, browse, and visualize ontologies and related gene product annotation (association) data. AmiGO can be used online at the Gene Ontology (GO) website to access the data provided by the GO Consortium; it can also be downloaded and installed to browse local ontologies and annotations. AmiGO is free open source software developed and maintained by the GO Consortium.
Date: January 15, 2009
Creator: Carbon, Seth; Ireland, Amelia; Mungall, Christopher J.; Shu, ShengQiang; Marshall, Brad & Lewis, Suzanna
Object Type: Article
System: The UNT Digital Library
Aqueous and gaseous nitrogen losses induced by fertilizer application (open access)

Aqueous and gaseous nitrogen losses induced by fertilizer application

In recent years concern has grown over the contribution of nitrogen (N) fertilizer use to nitrate (NO{sub 3}{sup -}) water pollution and nitrous oxide (N{sub 2}O), nitric oxide (NO), and ammonia (NH{sub 3}) atmospheric pollution. Characterizing soil N effluxes is essential in developing a strategy to mitigate N leaching and emissions to the atmosphere. In this paper, a previously described and tested mechanistic N cycle model (TOUGHREACT-N) was successfully tested against additional observations of soil pH and N{sub 2}O emissions after fertilization and irrigation, and before plant emergence. We used TOUGHREACT-N to explain the significantly different N gas emissions and nitrate leaching rates resulting from the different N fertilizer types, application methods, and soil properties. The N{sub 2}O emissions from NH{sub 4}{sup +}-N fertilizer were higher than from urea and NO{sub 3}{sup -}-N fertilizers in coarse-textured soils. This difference increased with decreases in fertilization application rate and increases in soil buffering capacity. In contrast to methods used to estimate global terrestrial gas emissions, we found strongly non-linear N{sub 2}O emissions as a function of fertilizer application rate and soil calcite content. Speciation of predicted gas N flux into N{sub 2}O and N{sub 2} depended on pH, fertilizer form, and soil …
Date: January 15, 2009
Creator: Gu, C.; Maggi, F.; Riley, W. J.; Hornberger, G. M.; Xu, T.; Oldenburg, C. M. et al.
Object Type: Article
System: The UNT Digital Library
ASSIMILATION OF DOPPLER RADAR DATA INTO NUMERICAL WEATHER MODELS (open access)

ASSIMILATION OF DOPPLER RADAR DATA INTO NUMERICAL WEATHER MODELS

During the year 2008, the United States National Weather Service (NWS) completed an eight fold increase in sampling capability for weather radars to 250 m resolution. This increase is expected to improve warning lead times by detecting small scale features sooner with increased reliability; however, current NWS operational model domains utilize grid spacing an order of magnitude larger than the radar data resolution, and therefore the added resolution of radar data is not fully exploited. The assimilation of radar reflectivity and velocity data into high resolution numerical weather model forecasts where grid spacing is comparable to the radar data resolution was investigated under a Laboratory Directed Research and Development (LDRD) 'quick hit' grant to determine the impact of improved data resolution on model predictions with specific initial proof of concept application to daily Savannah River Site operations and emergency response. Development of software to process NWS radar reflectivity and radial velocity data was undertaken for assimilation of observations into numerical models. Data values within the radar data volume undergo automated quality control (QC) analysis routines developed in support of this project to eliminate empty/missing data points, decrease anomalous propagation values, and determine error thresholds by utilizing the calculated variances among …
Date: January 15, 2009
Creator: Chiswell, S. & Buckley, R.
Object Type: Report
System: The UNT Digital Library
Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - October 1 - December 31, 2008 (open access)

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report - October 1 - December 31, 2008

Description. Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.
Date: January 15, 2009
Creator: Sisterson, DL
Object Type: Report
System: The UNT Digital Library
Atmospheric Radiation Measurement program climate research facility operations quarterly report October 1 - December 31, 2008. (open access)

Atmospheric Radiation Measurement program climate research facility operations quarterly report October 1 - December 31, 2008.

Individual raw data streams from instrumentation at the Atmospheric Radiation Measurement (ARM) Program Climate Research Facility (ACRF) fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent daily to the ACRF Archive, where they are made available to users. For each instrument, they calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual data stream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998. The US Department of Energy (DOE) requires national user facilities to report time-based operating data. The requirements concern the actual hours of operation (ACTUAL); the estimated maximum operation or uptime goal (OPSMAX), which accounts for planned downtime; and the VARIANCE [1-(ACTUAL/OPSMAX)], which accounts for unplanned downtime. The OPSMAX time for the first quarter of FY 2009 for the Southern Great Plains (SGP) site is 2,097.60 hours (0.95 x 2,208 hours this quarter). The OPSMAX for the North Slope Alaska (NSA) locale is 1,987.20 hours (0.90 x …
Date: January 15, 2009
Creator: Sisterson, D. L.
Object Type: Report
System: The UNT Digital Library
Certification Framework Based on Effective Trapping for Geologic Carbon Sequestration (open access)

Certification Framework Based on Effective Trapping for Geologic Carbon Sequestration

We have developed a certification framework (CF) for certifying the safety and effectiveness of geologic carbon sequestration (GCS) sites. Safety and effectiveness are achieved if CO{sub 2} and displaced brine have no significant impact on humans, other living things, resources, or the environment. In the CF, we relate effective trapping to CO{sub 2} leakage risk which takes into account both the impact and probability of leakage. We achieve simplicity in the CF by using (1) wells and faults as the potential leakage pathways, (2) compartments to represent environmental resources that may be impacted by leakage, (3) CO{sub 2} fluxes and concentrations in the compartments as proxies for impact to vulnerable entities, (4) broad ranges of storage formation properties to generate a catalog of simulated plume movements, and (5) probabilities of intersection of the CO{sub 2} plume with the conduits and compartments. We demonstrate the approach on a hypothetical GCS site in a Texas Gulf Coast saline formation. Through its generality and flexibility, the CF can contribute to the assessment of risk of CO{sub 2} and brine leakage as part of the certification process for licensing and permitting of GCS sites around the world regardless of the specific regulations in place …
Date: January 15, 2009
Creator: Oldenburg, Curtis M.; Bryant, Steven L. & Nicot, Jean-Philippe
Object Type: Article
System: The UNT Digital Library
Compliance of SLAC_s Laser Safety Program with OSHA Requirements for the Control of Hazardous Energy (open access)

Compliance of SLAC_s Laser Safety Program with OSHA Requirements for the Control of Hazardous Energy

SLAC's COHE program requires compliance with OSHA Regulation 29CFR1910.147, 'The control of hazardous energy (lockout/tagout)'. This regulation specifies lockout/tagout requirements during service and maintenance of equipment in which the unexpected energization or start up of the equipment, or release of stored energy, could cause injury to workers. Class 3B and Class 4 laser radiation must be considered as hazardous energy (as well as electrical energy in associated equipment, and other non-beam energy hazards) in laser facilities, and therefore requires careful COHE consideration. This paper describes how COHE is achieved at SLAC to protect workers against unexpected Class 3B or Class 4 laser radiation, independent of whether the mode of operation is normal, service, or maintenance.
Date: January 15, 2009
Creator: Woods, Michael
Object Type: Article
System: The UNT Digital Library
Diurnal oscillation of SBE expression in sorghum endosperm (open access)

Diurnal oscillation of SBE expression in sorghum endosperm

Spatial and temporal expression patterns of the sorghum SBEI, SBEIIA and SBEIIB genes, encoding, respectively, starch branching enzyme (SBE) I, IIA and IIB, in the developing endosperm of sorghum (Sorghum bicolor) were studied. Full-length genomic and cDNA clones for sorghum was cloned and the SBEIIA cDNA was used together with gene-specific probes for sorghum SBEIIB and SBEI. In contrast to sorghum SBEIIB, which was expressed primarily in endosperm and embryo, SBEIIA was expressed also in vegetative tissues. All three genes shared a similar temporal expression profile during endosperm development, with a maximum activity at 15-24 days after pollination. This is different from barley and maize where SBEI gene activity showed a significantly later onset compared to that of SBEIIA and SBEIIB. Expression of the three SBE genes in the sorghum endosperm exhibited a diurnal rhythm during a 24-h cycle.
Date: January 15, 2009
Creator: Sun, Chuanxin; Mutisya, J.; Rosenquist, S.; Baguma, Y. & Jansson, C.
Object Type: Article
System: The UNT Digital Library
Evaluation of the 2008 Lexus LS 600H Hybrid Synergy Drive System (open access)

Evaluation of the 2008 Lexus LS 600H Hybrid Synergy Drive System

Subsystems of the 2008 Lexus 600h hybrid electric vehicle (HEV) were studied and tested as part of an intensive benchmarking effort carried out to produce detailed information concerning the current state of nondomestic alternative vehicle technologies. Feedback provided by benchmarking efforts is particularly useful to partners of the Vehicle Technologies collaborative research program as it is essential in establishing reasonable yet challenging programmatic goals which facilitate development of competitive technologies. The competitive nature set forth by the Vehicle Technologies program not only promotes energy independence and economic stability, it also advocates the advancement of alternative vehicle technologies in an overall global perspective. These technologies greatly facilitate the potential to reduce dependency on depleting natural resources and mitigate harmful impacts of transportation upon the environment.
Date: January 15, 2009
Creator: Burress, T. A.; Coomer, C. L.; Campbell, S. L.; Wereszczak, A. A.; Cunningham, J. P.; Marlino, L. D. et al.
Object Type: Report
System: The UNT Digital Library
Full Steam Ahead for PV in US Homes? (open access)

Full Steam Ahead for PV in US Homes?

In October 2008, the United States Congress extended both the residential and commercial solar investment tax credits (ITCs) for an unprecedented eight years, lifted the $2,000 cap on the residential credit, removed the prohibition on utility use of the commercial credit, and eliminated restrictions on the use of both credits in conjunction with the Alternative Minimum Tax. These significant changes, which apply to systems placed in service on or after January 1, 2009, will increase the value of the solar credits for residential system owners in particular, and are likely--in conjunction with state, local, and utility rebate programs targeting solar--to spur significant growth in residential, commercial, and utility-scale photovoltaic (PV) installations in the years ahead. This article focuses specifically on the residential credit, describing three areas in which removal of the $2,000 cap on the residential ITC will have significant implications for PV rebate program administrators, PV system owners, and the PV industry.
Date: January 15, 2009
Creator: Bolinger, Mark A.; Barbose, Galen & Wiser, Ryan
Object Type: Article
System: The UNT Digital Library
GNEP Material Transportation, Storage and Disposal Analysis FY-08 Summary Report (open access)

GNEP Material Transportation, Storage and Disposal Analysis FY-08 Summary Report

This report provides a summary for FY-2008 of activities, analyses and products from the Material Transportation, Storage and Disposal (M-TSD) sub-task of Systems Analysis within the Advanced Fuel Cycle Research & Development area of the Global Nuclear Energy Partnership. The objective of this work is to evaluate near-term material management requirements for initial GNEP facilities and activities, long-term requirements for large-scale GNEP technology deployment, and alternatives and paths forward to meet these needs. For FY-08, the work expanded to include the Integrated Waste Management Strategy as well as integration with the newly formed Waste Forms Campaign. The M-TSD team was expanded with the addition of support from Savannah River National Lab (SRNL) to the existing team of Lawrence Livermore National Lab (LLNL), Argonne National Lab (ANL), Idaho National Lab (INL), Sandia National Lab (SNL) and University of Nevada - Reno (UN-R). During the first half of the year, analysis was focused on providing supporting technical analysis and documentation to support anticipated high-level decisions on program direction. A number of analyses were conducted and reports prepared as program deliverables. This work is briefly summarized in this report. Analyses provided informally to other program efforts are included in this report to provide …
Date: January 15, 2009
Creator: Halsey, W
Object Type: Report
System: The UNT Digital Library
HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT SUMMARY OF COMBINED THERMAL AND OPERATING LOADS WITH SEISMIC ANALYSIS (open access)

HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT SUMMARY OF COMBINED THERMAL AND OPERATING LOADS WITH SEISMIC ANALYSIS

This report summarizes the results of the Double-Shell Tank Thermal and Operating Loads Analysis (TaLA) combined with the Seismic Analysis. This combined analysis provides a thorough, defensible, and documented analysis that will become a part of the overall analysis of record for the Hanford double-shell tanks (DSTs). The bases of the analytical work presented herein are two ANSYS{reg_sign} finite element models that were developed to represent a bounding-case tank. The TaLA model includes the effects of temperature on material properties, creep, concrete cracking, and various waste and annulus pressure-loading conditions. The seismic model considers the interaction of the tanks with the surrounding soil including a range of soil properties, and the effects of the waste contents during a seismic event. The structural evaluations completed with the representative tank models do not reveal any structural deficiencies with the integrity of the DSTs. The analyses represent 60 years of use, which extends well beyond the current date. In addition, the temperature loads imposed on the model are significantly more severe than any service to date or proposed for the future. Bounding material properties were also selected to provide the most severe combinations. While the focus of the analyses was a bounding-case tank, …
Date: January 15, 2009
Creator: TC, MACKEY; JE, DEIBLER; MW, RINKER; KI, JOHNSON; FG, ABATT; NK, KARRI et al.
Object Type: Report
System: The UNT Digital Library
Laser Safety for the Experimental Halls at SLAC_s Linac Coherent Light Source (LCLS) (open access)

Laser Safety for the Experimental Halls at SLAC_s Linac Coherent Light Source (LCLS)

The LCLS at the SLAC National Accelerator Laboratory will be the world's first source of an intense hard x-ray laser beam, generating x-rays with wavelengths of 1nm and pulse durations less than 100fs. The ultrafast x-ray pulses will be used in pump-probe experiments to take stop-motion pictures of atoms and molecules in motion, with pulses powerful enough to take diffraction images of single molecules, enabling scientists to elucidate fundamental processes of chemistry and biology. Ultrafast conventional lasers will be used as the pump. In 2009, LCLS will deliver beam to the Atomic Molecular and Optical (AMO) Experiment, located in one of 3 x-ray Hutches in the Near Experimental Hall (NEH). The NEH includes a centralized Laser Hall, containing up to three Class 4 laser systems, three x-ray Hutches for experiments and vacuum transport tubes for delivering laser beams to the Hutches. The main components of the NEH laser systems are a Ti:sapphire oscillator, a regen amplifier, green pump lasers for the oscillator and regen, a pulse compressor and a harmonics conversion unit. Laser safety considerations and controls for the ultrafast laser beams, multiple laser controlled areas, and user facility issues are discussed.
Date: January 15, 2009
Creator: Woods, Michael; Anthony, Perry; Barat, Ken; Gilevich, Sasha; Hays, Greg & White, William E.
Object Type: Article
System: The UNT Digital Library
MEASUREMENT OF AMMONIA RELEASE FROM SALTSTONE (open access)

MEASUREMENT OF AMMONIA RELEASE FROM SALTSTONE

SRNL was requested by WSRC Waste Solidification Engineering to characterize the release of ammonia from saltstone curing at 95 C by performing experimental testing. These tests were performed with an MCU-type Tank 50H salt simulant containing 0, 50, and 200 mg/L ammonia. The testing program showed that above saltstone made from the 200 mg/L ammonia simulant, the vapor space ammonia concentration was about 2.7 mg/L vapor at 95 C. An upper 95% confidence value for this concentration was found to be 3.9 mg/L. Testing also showed that ammonia was chemically generated from curing saltstone at 95 C; the amount of ammonia generated was estimated to be equivalent to 121 mg/L additional ammonia in the salt solution feed. Even with chemical generation, the ammonia release from saltstone was found to be lower than its release from salt solution only with 200 mg/L ammonia.
Date: January 15, 2009
Creator: Zamecnik, J & Alex Cozzi, A
Object Type: Report
System: The UNT Digital Library
Mechanical properties of granular materials: A variational approach to grain-scale simulations (open access)

Mechanical properties of granular materials: A variational approach to grain-scale simulations

The mechanical properties of cohesionless granular materials are evaluated from grain-scale simulations. A three-dimensional pack of spherical grains is loaded by incremental displacements of its boundaries. The deformation is described as a sequence of equilibrium configurations. Each configuration is characterized by a minimum of the total potential energy. This minimum is computed using a modification of the conjugate gradient algorithm. Our simulations capture the nonlinear, path-dependent behavior of granular materials observed in experiments. Micromechanical analysis provides valuable insight into phenomena such as hysteresis, strain hardening and stress-induced anisotropy. Estimates of the effective bulk modulus, obtained with no adjustment of material parameters, are in agreement with published experimental data. The model is applied to evaluate the effects of hydrate dissociation in marine sediments. Weakening of the sediment is quantified as a reduction in the effective elastic moduli.
Date: January 15, 2009
Creator: Holtzman, R.; Silin, D.B. & Patzek, T.W.
Object Type: Article
System: The UNT Digital Library
Modeling Gas Transport in the Shallow Subsurface During the ZERT CO2 Release Test (open access)

Modeling Gas Transport in the Shallow Subsurface During the ZERT CO2 Release Test

We used the multiphase and multicomponent TOUGH2/EOS7CA model to carry out predictive simulations of CO{sub 2} injection into the shallow subsurface of an agricultural field in Bozeman, Montana. The purpose of the simulations was to inform the choice of CO{sub 2} injection rate and design of monitoring and detection activities for a CO{sub 2} release experiment. The release experiment configuration consists of a long horizontal well (70 m) installed at a depth of approximately 2.5 m into which CO{sub 2} is injected to mimic leakage from a geologic carbon sequestration site through a linear feature such as a fault. We estimated the permeability of the soil and cobble layers present at the site by manual inversion of measurements of soil CO{sub 2} flux from a vertical-well CO{sub 2} release. Based on these estimated permeability values, predictive simulations for the horizontal well showed that CO{sub 2} injection just below the water table creates an effective gas-flow pathway through the saturated zone up to the unsaturated zone. Once in the unsaturated zone, CO{sub 2} spreads out laterally within the cobble layer, where liquid saturation is relatively low. CO{sub 2} also migrates upward into the soil layer through the capillary barrier and seeps …
Date: January 15, 2009
Creator: Oldenburg, Curtis M.; Lewicki, Jennifer L.; Dobeck, Laura & Spangler, Lee
Object Type: Article
System: The UNT Digital Library
Molecular characterization of the stomach microbiota in patients with gastric cancer and controls (open access)

Molecular characterization of the stomach microbiota in patients with gastric cancer and controls

Persistent infection of the gastric mucosa by Helicobacter pylori, can initiate an inflammatory cascade that progresses into atrophic gastritis, a condition associated with reduced capacity for secretion of gastric acid and an increased risk in developing gastric cancer. The role of H. pylori as an initiator of inflammation is evident but the mechanism for development into gastric cancer has not yet been proven. A reduced capacity for gastric acid secretion allows survival and proliferation of other microbes that normally are killed by the acidic environment. It has been postulated that some of these species may be involved in the development of gastric cancer, however their identities are poorly defined. In this study, the gastric microbiota from ten patients with gastric cancer was characterized and compared with five dyspeptic controls using the molecular profiling approach, terminal-restriction fragment length polymorphism (T-RFLP), in combination with 16S rRNA gene cloning and sequencing. T-RFLP analysis revealed a complex bacterial community in the cancer patients that was not significantly different from the controls. Sequencing of 140 clones revealed 102 phylotypes, with representatives from five bacterial phyla (Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria and Fusobacteria). The data revealed a relatively low abundance of H. pylori and showed that the …
Date: January 15, 2009
Creator: Dicksved, J.; Lindberg, M.; Rosenquist, M.; Enroth, H.; Jansson, J.K. & Engstrand, L.
Object Type: Article
System: The UNT Digital Library
Parameter estimation from flowing fluid temperature logging data in unsaturated fractured rock using multiphase inverse modeling (open access)

Parameter estimation from flowing fluid temperature logging data in unsaturated fractured rock using multiphase inverse modeling

A simple conceptual model has been recently developed for analyzing pressure and temperature data from flowing fluid temperature logging (FFTL) in unsaturated fractured rock. Using this conceptual model, we developed an analytical solution for FFTL pressure response, and a semianalytical solution for FFTL temperature response. We also proposed a method for estimating fracture permeability from FFTL temperature data. The conceptual model was based on some simplifying assumptions, particularly that a single-phase airflow model was used. In this paper, we develop a more comprehensive numerical model of multiphase flow and heat transfer associated with FFTL. Using this numerical model, we perform a number of forward simulations to determine the parameters that have the strongest influence on the pressure and temperature response from FFTL. We then use the iTOUGH2 optimization code to estimate these most sensitive parameters through inverse modeling and to quantify the uncertainties associated with these estimated parameters. We conclude that FFTL can be utilized to determine permeability, porosity, and thermal conductivity of the fracture rock. Two other parameters, which are not properties of the fractured rock, have strong influence on FFTL response. These are pressure and temperature in the borehole that were at equilibrium with the fractured rock formation …
Date: January 15, 2009
Creator: Mukhopadhyay, S.; Tsang, Y. & Finsterle, S.
Object Type: Article
System: The UNT Digital Library
Physical test of a particle simulation model in a sheared granular system (open access)

Physical test of a particle simulation model in a sheared granular system

We report a detailed comparison of a slow gravity driven sheared granular flow with a computational model performed with the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). To our knowledge, this is the first thorough test of the LAMMPS model with a laboratory granular flow. In the experiments, grains flow inside a silo with a rectangular cross-section, and are sheared by a rough boundary on one side and smooth boundaries on the other sides. Individual grain position and motion are measured using a particle index matching imaging technique where a fluorescent dye is added to the interstitial liquid which has the same refractive index as the glass beads. The boundary imposes a packing order, and the grains are observed to flow in layers which get progressively more disordered with distance from the walls. The computations use a Cundall--Strack contact model between the grains, using contact parameters that have been used in many other previous studies, and ignore the hydrodynamic effects of the interstitial liquid. Computations are performed to understand the effect of particle coefficient of friction, elasticity, contact model, and polydispersity on mean flow properties. After appropriate scaling, we find that the mean velocity of the grains and the number density …
Date: January 15, 2009
Creator: Rycroft, Chris; Orpe, Ashish & Kudrolli, Arshad
Object Type: Article
System: The UNT Digital Library
Removal of Solids From Highly Enriched Uranium Solutions Using the H-Canyon Centrifuge (open access)

Removal of Solids From Highly Enriched Uranium Solutions Using the H-Canyon Centrifuge

Prior to the dissolution of Pu-containing materials in HB-Line, highly enriched uranium (HEU) solutions stored in Tanks 11.1 and 12.2 of H-Canyon must be transferred to provide storage space. The proposed plan is to centrifuge the solutions to remove solids which may present downstream criticality concerns or cause operational problems with the 1st Cycle solvent extraction due to the formation of stable emulsions. An evaluation of the efficiency of the H-Canyon centrifuge concluded that a sufficient amount (> 90%) of the solids in the Tank 11.1 and 12.2 solutions will be removed to prevent any problems. We based this conclusion on the particle size distribution of the solids isolated from samples of the solutions and the calculation of particle settling times in the centrifuge. The particle size distributions were calculated from images generated by scanning electron microscopy (SEM). The mean particle diameters for the distributions were 1-3 {micro}m. A significant fraction (30-50%) of the particles had diameters which were < 1 {micro}m; however, the mass of these solids is insignificant (< 1% of the total solids mass) when compared to particles with larger diameters. It is also probable that the number of submicron particles was overestimated by the software used …
Date: January 15, 2009
Creator: Rudisill, T. & Fernando Fondeur, F.
Object Type: Report
System: The UNT Digital Library