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Mass- and temperature-dependent diffusion coefficients for lightnoble gases for the TOUGH2-EOSN Model
This report describes modifications made to the EOSN module(Shan and Pruess, 2003) of the nonisothermal multiphase flow simulatorTOUGH2 (Pruess, et al., 1999). The EOSN fluid property module simulatestransport of water, brine, air, and noble gases or CO2 in the subsurface.In the standard version of the EOSN module, diffusion coefficients can bespecified by the user, but there is no allowance for liquid-phasediffusion coefficients to change with temperature. Furthermore, usersmust specify radiogenic sources of heat and helium for each element indata block GENER, which can be a time-consuming task for models withlarge numbers of elements. Our modifications seek to increase thefunctionality and efficiency of using TOUGH2-EOSN by allowing for mass-and temperature-dependent liquid-phase diffusion coefficients for heliumand neon and specification of radiogenic heat and helium production as aproperty of a material. The modified version is based on TOUGH2-EOSN andthus requires familiarity with the capabilities and input formats of theTOUGH2 code (Pruess, et al., 1999) and the EOSN module (Shan and Pruess,2003). This report only details our modifications and how to properlyutilize them.
Date:
April 13, 2007
Creator:
Andrews, J. L.; Finsterle, S. & Saar, M. O.
Object Type:
Report
System:
The UNT Digital Library
Long-term stability of organic carbon-stimulated chromatereduction in contaminated soils, and its relation to manganese redoxstatus
In-situ reduction of toxic Cr(V1) to less hazardous Cr(II1)is becoming a popular strategy for remediating contaminated soils.However, the long term stability of reduced Cr remains to be understood,especially given the common presence of MnfIIIJV) oxides that reoxidizeCr(II1). This 4.6 year laboratory study tracked Cr and Mn redoxtransformations in soils contaminated with Cr(V1) which were then treatedwith different amounts of organic carbon (OC). Changes in Cr and Mnoxidation states within soils were directly and nondestructively measuredusing micro X-ray absorption near edge structure spectroscopy. Chromatereduction was roughly lst-order, and the extent of reduction was enhancedwith higher OC additions. However, significant Cr(||1) reoxidationoccurred in soils exposed to the highest Cr(V1) concentrations (2,560 mgkg"'). Transient Cr(II1) reoxidation up to 420 mg kg1 was measured at 1.1years after OC treatment, followed by further reduction. Chromateconcentrations increased by 220 mg kgm1a t the end of the study (4.6years) in one soil. The causal role that Mn oxidation state had inreoxidizing Cr was supported by trends in Mn K-edge energies. Theseresults provide strong evidence for longterm dependence of soil Croxidation states on balances between OC availability and Mn redoxstatus.
Date:
March 13, 2007
Creator:
Tokunaga, Tetsu K.; Wan, Jiamin; Lanzirotti, Antonio; Sutton,Steve R.; Newville, Matthew & Rao, William
Object Type:
Article
System:
The UNT Digital Library
Conductive Carbon Coatings for Electrode Materials
A simple method for optimizing the carbon coatings on non-conductive battery cathode material powders has been developed at Lawrence Berkeley National Laboratory. The enhancement of the electronic conductivity of carbon coating enables minimization of the amount of carbon in the composites, allowing improvements in battery rate capability without compromising energy density. The invention is applicable to LiFePO{sub 4} and other cathode materials used in lithium ion or lithium metal batteries for high power applications such as power tools and hybrid or plug-in hybrid electric vehicles. The market for lithium ion batteries in consumer applications is currently $5 billion/year. Additionally, lithium ion battery sales for vehicular applications are projected to capture 5% of the hybrid and electric vehicle market by 2010, and 36% by 2015 (http://www.greencarcongress.com). LiFePO{sub 4} suffers from low intrinsic rate capability, which has been ascribed to the low electronic conductivity (10{sup -9} S cm{sup -1}). One of the most promising approaches to overcome this problem is the addition of conductive carbon. Co-synthesis methods are generally the most practical route for carbon coating particles. At the relatively low temperatures (<800 C) required to make LiFePO{sub 4}, however, only poorly conductive disordered carbons are produced from organic precursors. Thus, the …
Date:
July 13, 2007
Creator:
Doeff, Marca M.; Kostecki, Robert; Wilcox, James & Lau, Grace
Object Type:
Report
System:
The UNT Digital Library
Final Report-Passive Safety Optimization in Liquid Sodium-Cooled Reactors.
This report summarizes the results of a three-year collaboration between Argonne National Laboratory (ANL) and the Korea Atomic Energy Research Institute (KAERI) to identify and quantify the performance of innovative design features in metallic-fueled, sodium-cooled fast reactor designs. The objective of the work was to establish the reliability and safety margin enhancements provided by design innovations offering significant potential for construction, maintenance, and operating cost reductions. The project goal was accomplished with a combination of advanced model development (Task 1), analysis of innovative design and safety features (Tasks 2 and 3), and planning of key safety experiments (Task 4). Task 1--Computational Methods for Analysis of Passive Safety Design Features: An advanced three-dimensional subassembly thermal-hydraulic model was developed jointly and implemented in ANL and KAERI computer codes. The objective of the model development effort was to provide a high-accuracy capability to predict fuel, cladding, coolant, and structural temperatures in reactor fuel subassemblies, and thereby reduce the uncertainties associated with lower fidelity models previously used for safety and design analysis. The project included model formulation, implementation, and verification by application to available reactor tests performed at EBR-II. Task 2--Comparative Analysis and Evaluation of Innovative Design Features: Integrated safety assessments of innovative liquid …
Date:
August 13, 2007
Creator:
Cahalana, J. E. & Hahn, D.
Object Type:
Report
System:
The UNT Digital Library
High Average Power, High Energy Short Pulse Fiber Laser System
Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the …
Date:
November 13, 2007
Creator:
Messerly, M J
Object Type:
Report
System:
The UNT Digital Library
ALTERNATIVE MATERIALS TO PD MEMBRANES FOR HYDROGEN PURIFICATION
Development of advanced hydrogen separation membranes in support of hydrogen production processes such as coal gasification and as front end gas purifiers for fuel cell based system is paramount to the successful implementation of a national hydrogen economy. Current generation metallic hydrogen separation membranes are based on Pd-alloys. Although the technology has proven successful, at issue is the high cost of palladium. Evaluation of non-noble metal based dense metallic separation membranes is currently receiving national and international attention. The focal point of the reported work was to evaluate two different classes of materials for potential replacement of conventional Pd-alloy purification/diffuser membranes. Crystalline V-Ni-Ti and Amorphous Fe- and Co-based metallic glass alloys have been evaluated using both electrochemical and gaseous hydrogen permeation testing techniques..
Date:
November 13, 2007
Creator:
Adams, T & Paul Korinko, P
Object Type:
Article
System:
The UNT Digital Library
Papers from U.S. Department of Energy Science Undergraduate Laboratory Internship Program (SULI) 2007
A collection of student and intern research papers from Stanford Linear Accelerator center dealing with accelerator physics, crystal structure, BABAR, the GLAST mission, etc.
Date:
November 13, 2007
Creator:
Rock, S.E., (ed.) & Woods, M., (ed.)
Object Type:
Report
System:
The UNT Digital Library
Self-potential observations during hydraulic fracturing
The self-potential (SP) response during hydraulic fracturing of intact Sierra granite was investigated in the laboratory. Excellent correlation of pressure drop and SP suggests that the SP response is created primarily by electrokinetic coupling. For low pressures, the variation of SP with pressure drop is linear, indicating a constant coupling coefficient (Cc) of -200 mV/MPa. However for pressure drops >2 MPa, the magnitude of the Cc increases by 80% in an exponential trend. This increasing Cc is related to increasing permeability at high pore pressures caused by dilatancy of micro-cracks, and is explained by a decrease in the hydraulic tortuosity. Resistivity measurements reveal a decrease of 2% prior to hydraulic fracturing and a decrease of {approx}35% after fracturing. An asymmetric spatial SP response created by injectate diffusion into dilatant zones is observed prior to hydraulic fracturing, and in most cases this SP variation revealed the impending crack geometry seconds before failure. At rupture, injectate rushes into the new fracture area where the zeta potential is different than in the rock porosity, and an anomalous SP spike is observed. After fracturing, the spatial SP distribution reveals the direction of fracture propagation. Finally, during tensile cracking in a point load device with …
Date:
September 13, 2007
Creator:
Moore, Jeffrey R. & Glaser, Steven D.
Object Type:
Article
System:
The UNT Digital Library
Microstructural Characterization of Dislocation Networks During Harper-Dorn Creep of fcc, bcc, and hcp Metals and Alloys
Harper-Dorn (H-D) creep is observed in metals and geological materials exposed to very low stresses at temperatures close to the melting point. It is one of several types of creep processes wherein the steady-state strain rate is proportional to the applied stress, Nabarro-Herring creep and Coble creep being two other important processes. H-D creep can be somewhat insidious because the creep rates are much larger than those expected for Nabarro-Herring or Coble creep. Since the working conditions of structural components of power plants and propulsion systems, as well as the motion of the earth’s mantle all involve very low stresses, an understanding of the factors controlling H-D creep is critical in preventing failures associated with those higher-than-expected creep rates. The purpose of this investigation was to obtain missing microstructural information on the evolution of the dislocation structures during static annealing of materials with fcc, bcc and hcp structure and use obtained results to test predictive capabilities of the dislocation network theory of H-D creep. In our view the evolutionary processes during static annealing and during Harper-Dorn creep are intimately related. The materials used in this study were fcc aluminum, hcp zinc and bcc tin. All characterizations of dislocation structures, densities …
Date:
December 13, 2007
Creator:
Przystupa, Marek A.
Object Type:
Report
System:
The UNT Digital Library
Magnetism of NiMn2O4-Fe3O4 spinel interfaces
We investigate the magnetic properties of the isostructural spinel-spinel interface of NiMn{sub 2}O{sub 4}(NMO)-Fe{sub 3}O{sub 4}. Although the magnetic transition temperature of the NMO film is preserved, both bulk and interface sensitive measurements demonstrate that the interface exhibits strong interfacial magnetic coupling up to room temperature. While NMO thin films have a ferrimagnetic transition temperature of 60 K, both NiFe{sub 2}O{sub 4} and MnFe{sub 2}O{sub 4} are ferrimagnetic at room temperature. Our experimental results suggest that these magnetic properties arise from a thin interdiffused region of (Fe,Mn,Ni){sub 3}O{sub 4} at the interface, leading to Mn and Ni magnetic properties similar to those of MnFe{sub 2}O{sub 4} and NiFe{sub 2}O{sub 4}.
Date:
September 13, 2007
Creator:
Arenholz, Elke; Nelson-Cheeseman, B. B.; Chopdekar, R. V.; Bettinger, J. S.; Arenholz, E. & Suzuki, Y.
Object Type:
Article
System:
The UNT Digital Library
Model-Based Algorithms for Detecting Cable Damage from Time Domain Reflectometry Measurements
None
Date:
November 13, 2007
Creator:
Clark, G A
Object Type:
Article
System:
The UNT Digital Library
Data growth and its impact on the SCOP database: new developments
The Structural Classification of Proteins (SCOP) database is a comprehensive ordering of all proteins of known structure, according to their evolutionary and structural relationships. The SCOP hierarchy comprises the following levels: Species, Protein, Family, Superfamily, Fold and Class. While keeping the original classification scheme intact, we have changed the production of SCOP in order to cope with a rapid growth of new structural data and to facilitate the discovery of new protein relationships. We describe ongoing developments and new features implemented in SCOP. A new update protocol supports batch classification of new protein structuresby their detected relationships at Family and Superfamily levels in contrast to our previous sequential handling of new structural data by release date. We introduce pre-SCOP, a preview of the SCOP developmental version that enables earlier access to the information on new relationships. We also discuss the impact of worldwide Structural Genomics initiatives, which are producing new protein structures at an increasing rate, on the rates of discovery and growth of protein families and superfamilies. SCOP can be accessed at http://scop.mrc-lmb.cam.ac.uk/scop.
Date:
November 13, 2007
Creator:
Chandonia, John-Marc; Andreeva, Antonina; Howorth, Dave; Chandonia, John-Marc; Brenner, Steven E.; Hubbard, Tim J.P. et al.
Object Type:
Article
System:
The UNT Digital Library
Greensheet (Houston, Tex.), Vol. 38, No. 481, Ed. 1 Tuesday, November 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
November 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 536, Ed. 1 Thursday, December 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
December 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 482, Ed. 1 Tuesday, November 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
November 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 13, Ed. 1 Tuesday, February 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
February 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 62, Ed. 1 Tuesday, March 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
March 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 380, Ed. 1 Thursday, September 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
September 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 14, Ed. 1 Tuesday, February 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
February 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 537, Ed. 1 Thursday, December 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
December 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 274, Ed. 1 Friday, July 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
July 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 118, Ed. 1 Friday, April 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
April 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 381, Ed. 1 Thursday, September 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
September 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History
Greensheet (Houston, Tex.), Vol. 38, No. 61, Ed. 1 Tuesday, March 13, 2007
Free weekly newspaper that includes business and classified advertising.
Date:
March 13, 2007
Creator:
unknown
Object Type:
Newspaper
System:
The Portal to Texas History