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3D CFD Model of a Multi-Cell High Temperature Electrolysis Stack (open access)

3D CFD Model of a Multi-Cell High Temperature Electrolysis Stack

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis stack performance and steam electrolysis in the Idaho National Laboratory Integrated Lab Scale (ILS) experiment. The model is made of 60 planar cells stacked on top of each other operated as Solid Oxide Electrolysis Cells (SOEC). Details of the model geometry are specific to a stack that was fabricated by Ceramatec, Inc1. and tested at the Idaho National Laboratory. Inlet and outlet plenum flow and distribution are considered. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT2. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC userdefined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation overpotential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Variations in flow distribution, and species concentration are discussed. End effects of flow and per-cell voltage are also considered.
Date: November 1, 2007
Creator: Hawkes, G. L.; O'Brien, J. E. & Stoots, C. M.
Object Type: Article
System: The UNT Digital Library
Accident source terms for boiling water reactors with high burnup cores. (open access)

Accident source terms for boiling water reactors with high burnup cores.

The primary objective of this report is to provide the technical basis for development of recommendations for updates to the NUREG-1465 Source Term for BWRs that will extend its applicability to accidents involving high burnup (HBU) cores. However, a secondary objective is to re-examine the fundamental characteristics of the prescription for fission product release to containment described by NUREG-1465. This secondary objective is motivated by an interest to understand the extent to which research into the release and behaviors of radionuclides under accident conditions has altered best-estimate calculations of the integral response of BWRs to severe core damage sequences and the resulting radiological source terms to containment. This report, therefore, documents specific results of fission product source term analyses that will form the basis for the HBU supplement to NUREG-1465. However, commentary is also provided on observed differences between the composite results of the source term calculations performed here and those reflected NUREG-1465 itself.
Date: November 1, 2007
Creator: Gauntt, Randall O.; Powers, Dana Auburn & Leonard, Mark Thomas
Object Type: Report
System: The UNT Digital Library
Accommodating complexity and human behaviors in decision analysis. (open access)

Accommodating complexity and human behaviors in decision analysis.

This is the final report for a LDRD effort to address human behavior in decision support systems. One sister LDRD effort reports the extension of this work to include actual human choices and additional simulation analyses. Another provides the background for this effort and the programmatic directions for future work. This specific effort considered the feasibility of five aspects of model development required for analysis viability. To avoid the use of classified information, healthcare decisions and the system embedding them became the illustrative example for assessment.
Date: November 1, 2007
Creator: Backus, George A.; Siirola, John Daniel; Schoenwald, David Alan; Strip, David R.; Hirsch, Gary B.; Bastian, Mark S. et al.
Object Type: Report
System: The UNT Digital Library
ACRF Ingest Software Status: New, Current, and Future (November 2007) (open access)

ACRF Ingest Software Status: New, Current, and Future (November 2007)

The purpose of this report is to provide status of the ingest software used to process instrument data for the Atmospheric Radiation Measurement Program Climate Research Facility (ACRF). The report is divided into 4 sections: (1) for news about ingests currently under development, (2) for current production ingests, (3) for future ingest development plans, and (4) for information on retired ingests. Please note that datastreams beginning in “xxx” indicate cases where ingests run at multiple ACRF sites, which results in a datastream(s) for each location.
Date: November 1, 2007
Creator: Koontz, AS; Choudhury, S & Ermold, BD: Gaustad, KL
Object Type: Report
System: The UNT Digital Library
ADC and TDC implemented using FPGA (open access)

ADC and TDC implemented using FPGA

Several tests of FPGA devices programmed as analog waveform digitizers are discussed. The ADC uses the ramping-comparing scheme. A multi-channel ADC can be implemented with only a few resistors and capacitors as external components. A periodic logic levels are shaped by passive RC network to generate exponential ramps. The FPGA differential input buffers are used as comparators to compare the ramps with the input signals. The times at which these ramps cross the input signals are digitized by time-to-digital-converters (TDCs) implemented within the FPGA. The TDC portion of the logic alone has potentially a broad range of HEP/nuclear science applications. A 96-channel TDC card using FPGAs as TDCs being designed for the Fermilab MIPP electronics upgrade project is discussed. A deserializer circuit based on multisampling circuit used in the TDC, the 'Digital Phase Follower' (DPF) is also documented.
Date: November 1, 2007
Creator: Wu, Jinyuan; Hansen, Sten & Shi, Zonghan
Object Type: Article
System: The UNT Digital Library
Afghanistan: Post-War Governance, Security, and U.S. Policy (open access)

Afghanistan: Post-War Governance, Security, and U.S. Policy

This report considers the transition in government meant to stabilize Afghanistan. Specifically, the report covers the increasing amount of insurgency in the region. The south in particular has seen a rise in insurgency due to the lack of economic progress made. The report also discusses the NATO led troops in the region.
Date: November 1, 2007
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
The Albany News (Albany, Tex.), Vol. 132, No. 23, Ed. 1 Thursday, November 1, 2007 (open access)

The Albany News (Albany, Tex.), Vol. 132, No. 23, Ed. 1 Thursday, November 1, 2007

Weekly newspaper from Albany, Texas that includes local, county, and state news along with extensive advertising.
Date: November 1, 2007
Creator: Lucas, Melinda L.
Object Type: Newspaper
System: The Portal to Texas History
The Altus Times (Altus, Okla.), Vol. 109, No. 131, Ed. 1 Thursday, November 1, 2007 (open access)

The Altus Times (Altus, Okla.), Vol. 109, No. 131, Ed. 1 Thursday, November 1, 2007

Daily newspaper from Altus, Oklahoma that includes local, state, and national news along with advertising.
Date: November 1, 2007
Creator: Bush, Michael
Object Type: Newspaper
System: The Gateway to Oklahoma History
Aluminum alloys for satellite boxes : engineering guidelines for obtaining adequate strength while minimizing residual stresses and machining distortion. (open access)

Aluminum alloys for satellite boxes : engineering guidelines for obtaining adequate strength while minimizing residual stresses and machining distortion.

This report provides strategies for minimizing machining distortion in future designs of aluminum alloy satellite boxes, based in part on key findings from this investigation. The report outlines types of aluminum alloys and how they are heat treated, how residual stresses develop during heat treatment of age hardening alloys, ways residual stresses can be minimized, and the design of machining approaches to minimize distortion in parts that contain residual stresses. Specific recommendations are made regarding alloy selection, heat treatment, stress relieving, and machining procedures for boxes requiring various strength levels with emphasis on 6061 and 7075 aluminum alloys.
Date: November 1, 2007
Creator: Younger, Mandy S. & Eckelmeyer, Kenneth Hall
Object Type: Report
System: The UNT Digital Library
Analytic Approximation with Experimental Data of the Head-Tail Phase Difference from Continuous Transverse Excitation for Measuring Chromaticity (open access)

Analytic Approximation with Experimental Data of the Head-Tail Phase Difference from Continuous Transverse Excitation for Measuring Chromaticity

We will explore a method for measuring chromaticity by continuously kicking the beam transversely. This is called the continuous head-tail method for measuring chromaticity. The complete analytic approximation in terms of trigonometric functions is derived for zero transverse emittance beam. A simple formula for calculating chromaticity from experimental data is also shown. Finally the theory is compared with experimental data.
Date: November 1, 2007
Creator: Tan, C. Y. & Ranjbar, V. H.
Object Type: Article
System: The UNT Digital Library
Application for Permit to Operate a Class III Solid Waste Disposal Site at the Nevada Test Site Area 5 Asbestiform Low-Level Solid Waste Disposal Site (open access)

Application for Permit to Operate a Class III Solid Waste Disposal Site at the Nevada Test Site Area 5 Asbestiform Low-Level Solid Waste Disposal Site

The NTS is located approximately 105 kilometers (km) (65 miles [mi]) northwest of Las Vegas, Nevada (Figure 1). The U.S. Department of Energy (DOE) is the federal lands management authority for the NTS, and NSTec is the Management and Operations contractor. Access on and off the NTS is tightly controlled, restricted, and guarded on a 24-hour basis. The NTS has signs posted along its entire perimeter.
Date: November 1, 2007
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Archer County Advocate (Holliday, Tex.), Vol. 5, No. 30, Ed. 1 Thursday, November 1, 2007 (open access)

Archer County Advocate (Holliday, Tex.), Vol. 5, No. 30, Ed. 1 Thursday, November 1, 2007

Weekly newspaper from Holliday, Texas that includes local, state, and national news along with advertising.
Date: November 1, 2007
Creator: Stevens, Charlotte
Object Type: Newspaper
System: The Portal to Texas History
Archer County News (Archer City, Tex.), No. 44, Ed. 1 Thursday, November 1, 2007 (open access)

Archer County News (Archer City, Tex.), No. 44, Ed. 1 Thursday, November 1, 2007

Weekly newspaper from Archer City, Texas that includes local, state, and national news along with advertising.
Date: November 1, 2007
Creator: Lewis, Shelley
Object Type: Newspaper
System: The Portal to Texas History
Assessment of XM-19 as a Substitute for AISI 348 in ATR Service (open access)

Assessment of XM-19 as a Substitute for AISI 348 in ATR Service

It has been proposed that XM-19 alloy be considered as a possible replacement steel for AISI 348 in the construction of Advanced Test Reactor (ATR) capsules. AISI 348 works well, but is currently very difficult to obtain commercially. The superior and desirable mechanical properties of XM-19 alloy have been proven in non-nuclear applications, but no data are available regarding its use in radiation environments. While most 300 series alloys will meet the conditions required in ATR , it cannot be confidently assumed that XM-19 can be substituted without prior qualification in a radiation test. Compared to AISI 348, XM-19 will have an enhanced tendency for phase instabilities due to its higher levels of Ni and, especially, Si. However, transmutation of important elemental components in the highly thermalized ATR spectrum may have a very pronounced effect on its performance during irradiation. Not only will strong transmutation of Mn to Fe reduce the ductility and strength advantages provided by the higher initial Mn content of XM-19, but the extensive loss of Mn will also release from solution much of the N upon which the higher strength of XM-19 depends. In addition, the combined influence of transmutation and Inverse Kirkendall processes may lead …
Date: November 1, 2007
Creator: Garner, F. A.; Greenwood, L. R.; Mizia, R. E. & Tyler, C. R.
Object Type: Report
System: The UNT Digital Library
Assurance Requirements Compliance for the Greater Confinement Disposal Boreholes, Area 5 Radioactive Waste Management Site, Nevada Test Site (open access)

Assurance Requirements Compliance for the Greater Confinement Disposal Boreholes, Area 5 Radioactive Waste Management Site, Nevada Test Site

This paper addresses deficiencies identified with the. Performance Assessment for Greater Confinement Disposal (GCD) Boreholes compliance with the Title 40 Code of federal Regulations (CFR) Part 191.14, "Assurance Requirements" (CFR, 1985). The Transuransic Waste Disposal Federal Review Group (TFRG). and U.S Department of Energy Headquarters , need to concur that the assurance requirements have been met at the time of closure of the Area 5 Radioactive Waste Management Site.
Date: November 1, 2007
Creator: Wieland, Denise; Yucel, Vefa; Desotell, Lloyd; Shott, Greg; Crowe, Bruce; Krenzien, Susan et al.
Object Type: Report
System: The UNT Digital Library
Atmospheric Dispersion Model Validation in Low Wind Conditions (open access)

Atmospheric Dispersion Model Validation in Low Wind Conditions

Atmospheric plume dispersion models are used for a variety of purposes including emergency planning and response to hazardous material releases, determining force protection actions in the event of a Weapons of Mass Destruction (WMD) attack and for locating sources of pollution. This study provides a review of previous studies that examine the accuracy of atmospheric plume dispersion models for chemical releases. It considers the principles used to derive air dispersion plume models and looks at three specific models currently in use: Aerial Location of Hazardous Atmospheres (ALOHA), Emergency Prediction Information Code (EPIcode) and Second Order Closure Integrated Puff (SCIPUFF). Results from this study indicate over-prediction bias by the EPIcode and SCIPUFF models and under-prediction bias by the ALOHA model. The experiment parameters were for near field dispersion (less than 100 meters) in low wind speed conditions (less than 2 meters per second).
Date: November 1, 2007
Creator: Sawyer, Patrick
Object Type: Article
System: The UNT Digital Library
Automated mask creation from a 3D model using Faethm. (open access)

Automated mask creation from a 3D model using Faethm.

We have developed and implemented a method which given a three-dimensional object can infer from topology the two-dimensional masks needed to produce that object with surface micro-machining. The masks produced by this design tool can be generic, process independent masks, or if given process constraints, specific for a target process. This design tool calculates the two-dimensional mask set required to produce a given three-dimensional model by investigating the vertical topology of the model.
Date: November 1, 2007
Creator: Schiek, Richard Louis & Schmidt, Rodney Cannon
Object Type: Report
System: The UNT Digital Library
The Bastrop Advertiser (Bastrop, Tex.), Vol. 154, No. 71, Ed. 1 Thursday, November 1, 2007 (open access)

The Bastrop Advertiser (Bastrop, Tex.), Vol. 154, No. 71, Ed. 1 Thursday, November 1, 2007

Semi-weekly newspaper from Bastrop, Texas that includes local, state and national news along with advertising.
Date: November 1, 2007
Creator: McAuley, Davis
Object Type: Newspaper
System: The Portal to Texas History
The Baytown Sun (Baytown, Tex.), Vol. 86, No. 336, Ed. 1 Thursday, November 1, 2007 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 86, No. 336, Ed. 1 Thursday, November 1, 2007

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: November 1, 2007
Creator: Clements, Clifford E.
Object Type: Newspaper
System: The Portal to Texas History
Behavior-aware decision support systems : LDRD final report. (open access)

Behavior-aware decision support systems : LDRD final report.

As Sandia National Laboratories serves its mission to provide support for the security-related interests of the United States, it is faced with considering the behavioral responses that drive problems, mitigate interventions, or lead to unintended consequences. The effort described here expands earlier works in using healthcare simulation to develop behavior-aware decision support systems. This report focuses on using qualitative choice techniques and enhancing two analysis models developed in a sister project.
Date: November 1, 2007
Creator: Hirsch, Gary B.; Homer, Jack (Homer Consulting); Chenoweth, Brooke N.; Backus, George A. & Strip, David R.
Object Type: Report
System: The UNT Digital Library
Benchmarking MELCOR 1.8.2 for ITER Against Recent EVITA Results (open access)

Benchmarking MELCOR 1.8.2 for ITER Against Recent EVITA Results

A version of MELCOR 1.8.2 modified for use in ITER Preliminary Safety Report analyses was validated against recent data from the EVITA facility located in Cadarache, France. EVITA Test Series 7 was used for this study to verify MELCOR’s ability to predict the pressures, temperatures, cryoplate ice mass, and vaccum vessel (VV) condensate mass for test conditions in EVITA that include injections of steam, nitrogen, and water in to the EVITA VV after the walls had been heated to 165 ºC and the cryoplate had been cooled to -193 ºC. In general, the ability of MELCOR to predict the VV pressure and wall temperatures for the steam only and water only injection tests was very good. Predicted ice layer masses where larger than reported for the EVITA cryoplate, in particular for the steam only injection tests (~40% too high), and the predicted condensate masses were less that measured in EVITA. Both of these descrpancies can be explained by ice porosity. The modified MELCOR 1.8.2 over predicts the EVITA VV pressure for the co-injection tests (e.g., steam plus nitrogen, or water plus nitrogen injections) by almost a factor of two. Based on parametric runs that where made by increasing the predicted …
Date: November 1, 2007
Creator: Merrill, Brad J
Object Type: Report
System: The UNT Digital Library
Calculation of Accurate Hexagonal Discontinuity Factors for PARCS (open access)

Calculation of Accurate Hexagonal Discontinuity Factors for PARCS

In this study we derive a methodology for calculating discontinuity factors consistent with the Triangle-based Polynomial Expansion Nodal (TPEN) method implemented in PARCS for hexagonal reactor geometries. The accuracy of coarse-mesh nodal methods is greatly enhanced by permitting flux discontinuities at node boundaries, but the practice of calculating discontinuity factors from infinite-medium (zero-current) single bundle calculations may not be sufficiently accurate for more challenging problems in which there is a large amount of internodal neutron streaming. The authors therefore derive a TPEN-based method for calculating discontinuity factors that are exact with respect to generalized equivalence theory. The method is validated by reproducing the reference solution for a small hexagonal core.
Date: November 1, 2007
Creator: Pounders. J., Bandini, B. R. , Xu, Y, and Downar, T. J.
Object Type: Article
System: The UNT Digital Library
The Canadian Record (Canadian, Tex.), Vol. 117, No. 44, Ed. 1 Thursday, November 1, 2007 (open access)

The Canadian Record (Canadian, Tex.), Vol. 117, No. 44, Ed. 1 Thursday, November 1, 2007

Weekly newspaper from Canadian, Texas that includes local, state and national news along with some advertising.
Date: November 1, 2007
Creator: Brown, Laurie Ezzell
Object Type: Newspaper
System: The Portal to Texas History
Carbon Dioxide Transport and Sorption Behavior in Confined Coal Cores for Enhanced Coalbed Methane and CO2 Sequestration (open access)

Carbon Dioxide Transport and Sorption Behavior in Confined Coal Cores for Enhanced Coalbed Methane and CO2 Sequestration

Measurements of sorption isotherms and transport properties of CO2 in coal cores are important for designing enhanced coalbed methane/CO2 sequestration field projects. Sorption isotherms measured in the lab can provide the upper limit on the amount of CO2 that might be sorbed in these projects. Because sequestration sites will most likely be in unmineable coals, many of the coals will be deep and under considerable lithostatic and hydrostatic pressures. These lithostatic pressures may significantly reduce the sorption capacities and/or transport rates. Consequently, we have studied apparent sorption and diffusion in a coal core under confining pressure. A core from the important bituminous coal Pittsburgh #8 was kept under a constant, three-dimensional external stress; the sample was scanned by X-ray computer tomography (CT) before, then while it sorbed, CO2. Increases in sample density due to sorption were calculated from the CT images. Moreover, density distributions for small volume elements inside the core were calculated and analyzed. Qualitatively, the computerized tomography showed that gas sorption advanced at different rates in different regions of the core, and that diffusion and sorption progressed slowly. The amounts of CO2 sorbed were plotted vs. position (at fixed times) and vs. time (for various locations in the …
Date: November 1, 2007
Creator: Jikich, S.A.; McLendon, T.R.; Seshadri, K.S.; Irdi, G.A. & Smith, D.H.
Object Type: Article
System: The UNT Digital Library