Scientific Data Management Center for Enabling Technologies (open access)

Scientific Data Management Center for Enabling Technologies

Managing scientific data has been identified by the scientific community as one of the most important emerging needs because of the sheer volume and increasing complexity of data being collected. Effectively generating, managing, and analyzing this information requires a comprehensive, end-to-end approach to data management that encompasses all of the stages from the initial data acquisition to the final analysis of the data. Fortunately, the data management problems encountered by most scientific domains are common enough to be addressed through shared technology solutions. Based on community input, we have identified three significant requirements. First, more efficient access to storage systems is needed. In particular, parallel file system and I/O system improvements are needed to write and read large volumes of data without slowing a simulation, analysis, or visualization engine. These processes are complicated by the fact that scientific data are structured differently for specific application domains, and are stored in specialized file formats. Second, scientists require technologies to facilitate better understanding of their data, in particular the ability to effectively perform complex data analysis and searches over extremely large data sets. Specialized feature discovery and statistical analysis techniques are needed before the data can be understood or visualized. Furthermore, interactive …
Date: January 15, 2013
Creator: Vouk, Mladen A.
Object Type: Report
System: The UNT Digital Library
Laser-Mechanical Drilling for Geothermal Energy: Low-Contact Drilling Technology to Enable Economical EGS Wells (open access)

Laser-Mechanical Drilling for Geothermal Energy: Low-Contact Drilling Technology to Enable Economical EGS Wells

Broad Funding Opportunity Announcement Project: Foro Energy is developing a unique capability and hardware system to transmit high power lasers over long distances via fiber optic cables. This laser power is integrated with a mechanical drilling bit to enable rapid and sustained penetration of hard rock formations too costly to drill with mechanical drilling bits alone. The laser energy that is directed at the rock basically softens the rock, allowing the mechanical bit to more easily remove it. Foro Energy’s laser-assisted drill bits have the potential to be up to 10 times more economical than conventional hard-rock drilling technologies, making them an effective way to access the U.S. energy resources currently locked under hard rock formations.
Date: January 15, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
R&D ERL: High power RF systems (open access)

R&D ERL: High power RF systems

The Energy Recovery Linac (ERL) project, now under construction at Brookhaven National Laboratory, requires two high power RF systems. The first RF system is for the 703.75 MHz superconducting electron gun. The RF power from this system is used to drive nearly half an Ampere of beam current to 2.5 MeV. There is no provision to recover any of this energy so the minimum amplifier power is 1 MW. It consists of 1 MW CW klystron, transmitter and power supplies, 1 MW circulator, 1 MW dummy load and a two-way power splitter. The second RF system is for the 703.75 MHz superconducting cavity. The system accelerates the beam to 54.7 MeV and recovers this energy. It will provide up to 50 kW of CW RF power to the cavity. It consists of 50 kW transmitter, circulator, and dummy load. This paper describes the two high power RF systems and presents the test data for both.
Date: January 15, 2010
Creator: Zaltsman, A.
Object Type: Report
System: The UNT Digital Library
Thermal single-well injection-withdrawal tracer tests for determining fracture-matrix heat transfer area (open access)

Thermal single-well injection-withdrawal tracer tests for determining fracture-matrix heat transfer area

Single-well injection-withdrawal (SWIW) tracer tests involve injection of traced fluid and subsequent tracer recovery from the same well, usually with some quiescent time between the injection and withdrawal periods. SWIW are insensitive to variations in advective processes that arise from formation heterogeneities, because upon withdrawal, fluid parcels tend to retrace the paths taken during injection. However, SWIW are sensitive to diffusive processes, such as diffusive exchange of conservative or reactive solutes between fractures and rock matrix. This paper focuses on SWIW tests in which temperature itself is used as a tracer. Numerical simulations demonstrate the sensitivity of temperature returns to fracture-matrix interaction. We consider thermal SWIW response to the two primary reservoir improvements targeted with stimulation, (1) making additional fractures accessible to injected fluids, and (2) increasing the aperture and permeability of pre-existing fractures. It is found that temperature returns in SWIW tests are insensitive to (2), while providing a strong signal of more rapid temperature recovery during the withdrawal phase for (1).
Date: January 15, 2010
Creator: Pruess, K. & Doughty, C.
Object Type: Article
System: The UNT Digital Library
Methane Hydrate Dissociation by Depressurization in a Mount Elbert Sandstone Sample: Experimental Observations and Numerical Simulations (open access)

Methane Hydrate Dissociation by Depressurization in a Mount Elbert Sandstone Sample: Experimental Observations and Numerical Simulations

A preserved sample of hydrate-bearing sandstone from the Mount Elbert Test Well was dissociated by depressurization while monitoring the internal temperature of the sample in two locations and the density changes at high spatial resolution using x-ray CT scanning. The sample contained two distinct regions having different porosity and grain size distributions. The hydrate dissociation occurred initially throughout the sample as a result of depressing the pressure below the stability pressure. This initial stage reduced the temperature to the equilibrium point, which was maintained above the ice point. After that, dissociation occurred from the outside in as a result of heat transfer from the controlled temperature bath surrounding the pressure vessel. Numerical modeling of the test using TOUGH+HYDRATE yielded a gas production curve that closely matches the experimentally measured curve.
Date: January 15, 2011
Creator: Kneafsey, T. & Moridis, G.J.
Object Type: Article
System: The UNT Digital Library
Factors governing sustainable groundwater pumping near a river (open access)

Factors governing sustainable groundwater pumping near a river

The objective of this paper is to provide new insights into processes affecting riverbank filtration (RBF). We consider a system with an inflatable dam installed for enhancing water production from downstream collector wells. Using a numerical model, we investigate the impact of groundwater pumping and dam operation on the hydrodynamics in the aquifer and water production. We focus our study on two processes that potentially limit water production of an RBF system: the development of an unsaturated zone and riverbed clogging. We quantify river clogging by calibrating a time-dependent riverbed permeability function based on knowledge of pumping rate, river stage, and temperature. The dynamics of the estimated riverbed permeability reflects clogging and scouring mechanisms. Our results indicate that (1) riverbed permeability is the dominant factor affecting infiltration needed for sustainable RBF production; (2) dam operation can influence pumping efficiency and prevent the development of an unsaturated zone beneath the riverbed only under conditions of sufficient riverbed permeability; (3) slow river velocity, caused by dam raising during summer months, may lead to sedimentation and deposition of fine-grained material within the riverbed, which may clog the riverbed, limiting recharge to the collector wells and contributing to the development of an unsaturated zone …
Date: January 15, 2011
Creator: Zhang, Y.; Hubbard, S. S. & Finsterle, S.
Object Type: Article
System: The UNT Digital Library
Massively Parallel Loading (open access)

Massively Parallel Loading

None
Date: January 15, 2013
Creator: Frings, W.; Ahn, D. H.; LeGendre, M.; Gamblin, T.; de Supinski, B. R. & Wolf, F.
Object Type: Article
System: The UNT Digital Library
Pore-Water Extraction Scale-Up Study for the SX Tank Farm (open access)

Pore-Water Extraction Scale-Up Study for the SX Tank Farm

The phenomena related to pore-water extraction from unsaturated sediments have been previously examined with limited laboratory experiments and numerical modeling. However, key scale-up issues have not yet been addressed. Laboratory experiments and numerical modeling were conducted to specifically examine pore-water extraction for sediment conditions relevant to the vadose zone beneath the SX Tank Farm at Hanford Site in southeastern Washington State. Available SX Tank Farm data were evaluated to generate a conceptual model of the subsurface for a targeted pore-water extraction application in areas with elevated moisture and Tc-99 concentration. The hydraulic properties of the types of porous media representative of the SX Tank Farm target application were determined using sediment mixtures prepared in the laboratory based on available borehole sediment particle size data. Numerical modeling was used as an evaluation tool for scale-up of pore-water extraction for targeted field applications.
Date: January 15, 2013
Creator: Truex, Michael J.; Oostrom, Martinus; Wietsma, Thomas W.; Last, George V. & Lanigan, David C.
Object Type: Report
System: The UNT Digital Library
Estimating the upper limit of gas production from Class 2 hydrate accumulations in the permafrost: 2. Alternative well designs and sensitivity analysis (open access)

Estimating the upper limit of gas production from Class 2 hydrate accumulations in the permafrost: 2. Alternative well designs and sensitivity analysis

In the second paper of this series, we evaluate two additional well designs for production from permafrost-associated (PA) hydrate deposits. Both designs are within the capabilities of conventional technology. We determine that large volumes of gas can be produced at high rates (several MMSCFD) for long times using either well design. The production approach involves initial fluid withdrawal from the water zone underneath the hydrate-bearing layer (HBL). The production process follows a cyclical pattern, with each cycle composed of two stages: a long stage (months to years) of increasing gas production and decreasing water production, and a short stage (days to weeks) that involves destruction of the secondary hydrate (mainly through warm water injection) that evolves during the first stage, and is followed by a reduction in the fluid withdrawal rate. A well configuration with completion throughout the HBL leads to high production rates, but also the creation of a secondary hydrate barrier around the well that needs to be destroyed regularly by water injection. However, a configuration that initially involves heating of the outer surface of the wellbore and later continuous injection of warm water at low rates (Case C) appears to deliver optimum performance over the period it …
Date: January 15, 2011
Creator: Moridis, G. & Reagan, M. T.
Object Type: Article
System: The UNT Digital Library
Coarse and Fine Grain Parallelism Performance Exploration in Ares (open access)

Coarse and Fine Grain Parallelism Performance Exploration in Ares

None
Date: January 15, 2013
Creator: Collette, M R & Karlin, I
Object Type: Article
System: The UNT Digital Library
Summary of the Special Analysis of Savannah River Depleted Uranium Trioxide Demonstrating the Before and After Impacts on the DOE Order 435.1 Performance Objective and the Peak Dose (open access)

Summary of the Special Analysis of Savannah River Depleted Uranium Trioxide Demonstrating the Before and After Impacts on the DOE Order 435.1 Performance Objective and the Peak Dose

This report summarizes the special analysis (SA) of the Savannah River Depleted Uranium Trioxide waste stream (SVRSURANIUM03, Revision 1) demonstrating the before and after impacts of the waste stream to the DOE Order 435.1 performance objective at the disposal facility, and the peak dose. The Nevada Division of Environmental Protection (NDEP) requested this SA and asked the Nevada Site Office (NSO) to run the SA deterministically and assume that all the model conditions remain the same regardless of the length of time to the peak dose. Although the NDEP accepts that DOE Order 435.1 requires a compliance period of 1,000 years, it also requested to know what year, if any, the specific DOE performance objectives will be exceeded. Given the NDEP’s requested model conditions, the SA demonstrates the Rn-222 peak dose will occur in about 2 million years and will exceed the performance objective in about 6,000 years. The 0.25 mSv y-1 all-pathway performance objective was not exceeded for the resident scenario after reaching the 4 million year peak dose.
Date: January 15, 2011
Creator: Shott, G.J.
Object Type: Report
System: The UNT Digital Library
A General Theorem Relating the Bulk Topological Number to Edge States in Two-dimensional Insulators (open access)

A General Theorem Relating the Bulk Topological Number to Edge States in Two-dimensional Insulators

We prove a general theorem on the relation between the bulk topological quantum number and the edge states in two dimensional insulators. It is shown that whenever there is a topological order in bulk, characterized by a non-vanishing Chern number, even if it is defined for a non-conserved quantity such as spin in the case of the spin Hall effect, one can always infer the existence of gapless edge states under certain twisted boundary conditions that allow tunneling between edges. This relation is robust against disorder and interactions, and it provides a unified topological classification of both the quantum (charge) Hall effect and the quantum spin Hall effect. In addition, it reconciles the apparent conflict between the stability of bulk topological order and the instability of gapless edge states in systems with open boundaries (as known happening in the spin Hall case). The consequences of time reversal invariance for bulk topological order and edge state dynamics are further studied in the present framework.
Date: January 15, 2010
Creator: Qi, Xiao-Liang; /Tsinghua U., Beijing /Stanford U., Phys. Dept.; Wu, Yong-Shi; U., /Utah; Zhang, Shou-Cheng & /Stanford U., Phys. Dept. /Tsinghua U., Beijing
Object Type: Article
System: The UNT Digital Library
Photonics Research and Development (open access)

Photonics Research and Development

During the period August 2005 through October 2009, the UNLV Research Foundation (UNLVRF), a non-profit affiliate of the University of Nevada, Las Vegas (UNLV), in collaboration with UNLV’s Colleges of Science and Engineering; Boston University (BU); Oak Ridge National Laboratory (ORNL); and Sunlight Direct, LLC, has managed and conducted a diverse and comprehensive research and development program focused on light-emitting diode (LED) technologies that provide significantly improved characteristics for lighting and display applications. This final technical report provides detailed information on the nature of the tasks, the results of the research, and the deliverables. It is estimated that about five percent of the energy used in the nation is for lighting homes, buildings and streets, accounting for some 25 percent of the average home’s electric bill. However, the figure is significantly higher for the commercial sector. About 60 percent of the electricity for businesses is for lighting. Thus replacement of current lighting with solid-state lighting technology has the potential to significantly reduce this nation’s energy consumption – by some estimates, possibly as high as 20%. The primary objective of this multi-year R&D project has been to develop and advance lighting technologies to improve national energy conversion efficiencies; reduce heat load; …
Date: January 15, 2010
Creator: Pookpanratana, Sujitra; Shlayan, Neveen; Venkat, Rama; Das, Bisjwajit; Boehm, Bob; Heske, Clemens et al.
Object Type: Report
System: The UNT Digital Library
Magic Doping Fractions in High-Temperature Superconductors (open access)

Magic Doping Fractions in High-Temperature Superconductors

We report hole-doping dependence of the in-plane resistivity {rho}{sub ab} in a cuprate superconductor La{sub 2-x}Sr{sub x}CuO{sub 4}, carefully examined using a series of high-quality single crystals. Our detailed measurements find a tendency towards charge ordering at particular rational hole doping fractions of 1/16, 3/32, 1/8, and 3/16. This observation appears to suggest a specific form of charge order and is most consistent with the recent theoretical prediction of the checkerboard-type ordering of the Cooper pairs at rational doping fractions x = (2m + 1)/2{sup n}, with integers m and n.
Date: January 15, 2010
Creator: Komiya, Seiki; Chen, Han-Dong; Zhang, Shou-Cheng & Ando, Yoichi
Object Type: Article
System: The UNT Digital Library
Liquid Metal Walls, Lithium, And Low Recycling Boundary Conditions In Tokamaks (open access)

Liquid Metal Walls, Lithium, And Low Recycling Boundary Conditions In Tokamaks

At present, the only solid material believed to be a viable option for plasma-facing components (PFCs) in a fusion reactor is tungsten. Operated at the lower temperatures typical of present-day fusion experiments, tungsten is known to suffer from surface degradation during long-term exposure to helium-containing plasmas, leading to reduced thermal conduction to the bulk, and enhanced erosion. Existing alloys are also quite brittle at temperatures under 700oC. However, at a sufficiently high operating temperature (700 - 1000 oC), tungsten is selfannealing and it is expected that surface damage will be reduced to the point where tungsten PFCs will have an acceptable lifetime in a reactor environment. The existence of only one potentially viable option for solid PFCs, though, constitutes one of the most significant restrictions on design space for DEMO and follow-on fusion reactors. In contrast, there are several candidates for liquid metal-based PFCs, including gallium, tin, lithium, and tin-lithium eutectics. We will discuss options for liquid metal walls in tokamaks, looking at both high and low recycling materials. We will then focus in particular on one of the candidate liquids, lithium. Lithium is known to have a high chemical affinity for hydrogen, and has been shown in test stands1 …
Date: January 15, 2010
Creator: Majeski, R.
Object Type: Article
System: The UNT Digital Library
Intrinsic Spin-Hall Effect in n-Doped Bulk GaAs (open access)

Intrinsic Spin-Hall Effect in n-Doped Bulk GaAs

We show that the bulk Dresselhauss (k{sup 3}) spin-orbit coupling term leads to an intrinsic spin-Hall effect in n-doped bulk GaAs, but without the appearance of uniform magnetization. The spin-Hall effect in strained and unstrained bulk GaAs has been recently observed experimentally by Kato et. al. [1]. We show that the experimental result is quantitatively consistent with the intrinsic spin-Hall effect due to the Dresselhauss term, when lifetime broadening is taken into account. On the other hand, extrinsic contribution to the spin-Hall effect is several orders of magnitude smaller than the observed effect.
Date: January 15, 2010
Creator: Bernevig, B.Andrei; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type: Report
System: The UNT Digital Library
Orbitronics: the Intrinsic Orbital Hall Effect in p-Doped Silicon (open access)

Orbitronics: the Intrinsic Orbital Hall Effect in p-Doped Silicon

The spin Hall effect depends crucially on the intrinsic spin-orbit coupling of the energy band. Because of the smaller spin-orbit coupling in silicon, the spin Hall effect is expected to be much reduced. We show that the electric field in p-doped silicon can induce a dissipationless orbital current in a fashion reminiscent of the spin Hall effect. The vertex correction due to impurity scattering vanishes and the effect is therefore robust against disorder. The orbital Hall effect can lead to the accumulation of local orbital momentum at the edge of the sample, and can be detected by the Kerr effect.
Date: January 15, 2010
Creator: Bernevig, B.Andrei; Hughes, Taylor L.; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type: Article
System: The UNT Digital Library
Spin Splitting and Spin Current in Strained Bulk Semiconductors (open access)

Spin Splitting and Spin Current in Strained Bulk Semiconductors

We present a theory for two recent experiments in bulk strained semiconductors and show that a new, previously overlooked, strain spin-orbit coupling term may play a fundamental role. We propose simple experiments that could clarify the origin of strain-induced spin-orbit coupling terms in inversion asymmetric semiconductors. We predict that a uniform magnetization parallel to the electric field will be induced in the samples studied in for specific directions of the applied electric field. We also propose special geometries to detect spin currents in strained semiconductors.
Date: January 15, 2010
Creator: Bernevig, B.Andrei; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type: Article
System: The UNT Digital Library
A sufficient condition for the absence of the sign problem in the fermionic quantum Monte-Carlo algorithm (open access)

A sufficient condition for the absence of the sign problem in the fermionic quantum Monte-Carlo algorithm

Quantum Monte-Carlo (QMC) simulations involving fermions have the notorious sign problem. Some well-known exceptions of the auxiliary field QMC algorithm rely on the factorizibility of the fermion determinant. Recently, a fermionic QMC algorithm has been found in which the fermion determinant may not necessarily factorizable, but can instead be expressed as a product of complex conjugate pairs of eigenvalues, thus eliminating the sign problem for a much wider class of models. In this paper, we present general conditions for the applicability of this algorithm and point out that it is deeply related to the time reversal symmetry of the fermion matrix. We apply this method to various models of strongly correlated systems at all doping levels and lattice geometries, and show that many novel phases can be simulated without the sign problem.
Date: January 15, 2010
Creator: Wu, Congjun; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type: Article
System: The UNT Digital Library
Ferromagnetism in the Mott insulator Ba2NaOsO6 (open access)

Ferromagnetism in the Mott insulator Ba2NaOsO6

Results are presented of single crystal structural, thermodynamic, and reflectivity measurements of the double-perovskite Ba{sub 2}NaOsO{sub 6}. These characterize the material as a 5d1 ferromagnetic Mott insulator with an ordered moment of {approx} 0.2 {micro}B per formula unit and T{sub C} = 6.8(3) K. The magnetic entropy associated with this phase transition is close to Rln2, indicating that the quartet groundstate anticipated from consideration of the crystal structure is split, consistent with a scenario in which the ferromagnetism is associated with orbital ordering.
Date: January 15, 2010
Creator: Erickson, A. S.; Misra, S.; Miller, G. J.; Harrison, W. A.; Kim, J. M. & Fisher, I. R.
Object Type: Article
System: The UNT Digital Library
Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report October 1–December 31, 2009 (open access)

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report October 1–December 31, 2009

Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility 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 approximately daily to the ARM Data 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 datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.
Date: January 15, 2010
Creator: Sisterson, D. L.
Object Type: Report
System: The UNT Digital Library
Spin-orbit Coupling Induced Magnetism in the d-density Wave Phase of La2-xBaxCuO4 Superconductors (open access)

Spin-orbit Coupling Induced Magnetism in the d-density Wave Phase of La2-xBaxCuO4 Superconductors

We study the effects of spin-orbit coupling in the d-density wave (DDW) phase. In the low-temperature orthorhombic phase of La{sub 2-x}Ba{sub x}CuO{sub 4}, we find that spin-orbit coupling induces ferromagnetic moments in the DDW phase, which are polarized along the [110] direction with a considerable magnitude. This effect does not exist in the superconducting phase. On the other hand, if the d-density wave order does not exist at zero field, a magnetic field along the [110] direction always induces such a staggered orbital current. We discuss experimental constraints on the DDW states in light of our theoretical predictions.
Date: January 15, 2010
Creator: Wu, Congjun; /Stanford U., Phys. Dept. /Santa Barbara, KITP; Zaanen, Jan; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type: Article
System: The UNT Digital Library
Quantum Spin Hall Effect (open access)

Quantum Spin Hall Effect

The quantum Hall liquid is a novel state of matter with profound emergent properties such as fractional charge and statistics. Existence of the quantum Hall effect requires breaking of the time reversal symmetry caused by an external magnetic field. In this work, we predict a quantized spin Hall effect in the absence of any magnetic field, where the intrinsic spin Hall conductance is quantized in units of 2 e/4{pi}. The degenerate quantum Landau levels are created by the spin-orbit coupling in conventional semiconductors in the presence of a strain gradient. This new state of matter has many profound correlated properties described by a topological field theory.
Date: January 15, 2010
Creator: Bernevig, B.Andrei; Zhang, Shou-Cheng & /Stanford U., Phys. Dept.
Object Type: Article
System: The UNT Digital Library
100-KE REACTOR CORE REMOVAL PROJECT ALTERNATIVE ANALYSIS WORKSHOP REPORT (open access)

100-KE REACTOR CORE REMOVAL PROJECT ALTERNATIVE ANALYSIS WORKSHOP REPORT

On December 15-16, 2009, a 100-KE Reactor Core Removal Project Alternative Analysis Workshop was conducted at the Washington State University Consolidated Information Center, Room 214. Colburn Kennedy, Project Director, CH2M HILL Plateau Remediation Company (CHPRC) requested the workshop and Richard Harrington provided facilitation. The purpose of the session was to select the preferred Bio Shield Alternative, for integration with the Thermal Shield and Core Removal and develop the path forward to proceed with project delivery. Prior to this workshop, the S.A. Robotics (SAR) Obstruction Removal Alternatives Analysis (565-DLV-062) report was issued, for use prior to and throughout the session, to all the team members. The multidisciplinary team consisted ofrepresentatives from 100-KE Project Management, Engineering, Radcon, Nuclear Safety, Fire Protection, Crane/Rigging, SAR Project Engineering, the Department of Energy Richland Field Office, Environmental Protection Agency, Washington State Department of Ecology, Defense Nuclear Facility Safety Board, and Deactivation and Decommission subject matter experts from corporate CH2M HILL and Lucas. Appendix D contains the workshop agenda, guidelines and expectations, opening remarks, and attendance roster going into followed throughout the workshop. The team was successful in selecting the preferred alternative and developing an eight-point path forward action plan to proceed with conceptual design. Conventional Demolition …
Date: January 15, 2010
Creator: Harrington, R. A.
Object Type: Report
System: The UNT Digital Library