Temperature-induced martensite in magnetic shape memory Fe{sub 2}MnGa observed by photoemission electron microscopy (open access)

Temperature-induced martensite in magnetic shape memory Fe{sub 2}MnGa observed by photoemission electron microscopy

The magnetic domain structure in single crystals of a Heusler shape memory compound near the composition Fe{sub 2}MnGa was observed during phase transition by photoelectron emission microscopy at Beamline 11.0.1.1 of the Advanced Light Source. The behavior is comparable with recent observations of an adaptive martensite phase in prototype Ni{sub 2}MnGa, although the pinning in the recent work is an epitaxial interface and in this work the e#11;ective pinning plane is a boundary between martensitic variants that transform in a self-accommodating way from the single crystal austenite phase present at high temperatures. Temperature dependent observations of the twinning structure give information as to the coupling behavior between the magnetism and the structural evolution.
Date: January 18, 2012
Creator: Jenkins, Catherine; Scholl, Andreas; Kainuma, R.; Elmers, Hans-Joachim & Omori, Toshihiro
System: The UNT Digital Library
Using fully coupled hydro-geomechanical numerical test bed to study reservoir stimulation with low hydraulic pressure (open access)

Using fully coupled hydro-geomechanical numerical test bed to study reservoir stimulation with low hydraulic pressure

None
Date: January 18, 2012
Creator: Fu, P.; Johnson, S. M. & Carrigan, C. R.
System: The UNT Digital Library
EVALUATION OF SPRING OPERATED RELIEF VALVE MAINTENANCE INTERVALS AND EXTENSION OF MAINTENANCE TIMES USING A WEIBULL ANALYSIS WITH MODIFIED BAYESIAN UPDATING (open access)

EVALUATION OF SPRING OPERATED RELIEF VALVE MAINTENANCE INTERVALS AND EXTENSION OF MAINTENANCE TIMES USING A WEIBULL ANALYSIS WITH MODIFIED BAYESIAN UPDATING

The Savannah River Site (SRS) spring operated pressure relief valve (SORV) maintenance intervals were evaluated using an approach provided by the American Petroleum Institute (API RP 581) for risk-based inspection technology (RBI). In addition, the impact of extending the inspection schedule was evaluated using Monte Carlo Simulation (MCS). The API RP 581 approach is characterized as a Weibull analysis with modified Bayesian updating provided by SRS SORV proof testing experience. Initial Weibull parameter estimates were updated as per SRS's historical proof test records contained in the Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD). The API RP 581 methodology was used to estimate the SORV's probability of failing on demand (PFD), and the annual expected risk. The API RP 581 methodology indicates that the current SRS maintenance plan is conservative. Cost savings may be attained in certain mild service applications that present low PFD and overall risk. Current practices are reviewed and recommendations are made for extending inspection intervals. The paper gives an illustration of the inspection costs versus the associated risks by using API RP 581 Risk Based Inspection (RBI) Technology. A cost effective maintenance frequency balancing both financial risk and inspection cost is demonstrated.
Date: January 18, 2011
Creator: Harris, S.; Gross, R. & Mitchell, E.
System: The UNT Digital Library
Energetics of Oxygen Adatoms, Hydroxyl Species and Water Dissociation on Pt(111) (open access)

Energetics of Oxygen Adatoms, Hydroxyl Species and Water Dissociation on Pt(111)

None
Date: January 18, 2013
Creator: Karp, Eric M.; Campbell, Charles T.; /Washington U., Dept. Chem.; Studt, Felix; Abild-Pedersen, Frank; Norskov, Jens K. et al.
System: The UNT Digital Library
A Framework for Incorporating General Domain Knowledge into Latent Dirichlet Allocation using First-Order Logic (open access)

A Framework for Incorporating General Domain Knowledge into Latent Dirichlet Allocation using First-Order Logic

Topic models have been used successfully for a variety of problems, often in the form of application-specific extensions of the basic Latent Dirichlet Allocation (LDA) model. Because deriving these new models in order to encode domain knowledge can be difficult and time-consuming, we propose the Fold-all model, which allows the user to specify general domain knowledge in First-Order Logic (FOL). However, combining topic modeling with FOL can result in inference problems beyond the capabilities of existing techniques. We have therefore developed a scalable inference technique using stochastic gradient descent which may also be useful to the Markov Logic Network (MLN) research community. Experiments demonstrate the expressive power of Fold-all, as well as the scalability of our proposed inference method.
Date: January 18, 2011
Creator: Andrzejewski, D.; Zhu, X.; Craven, M. & Recht, B.
System: The UNT Digital Library
Energy Savings Assessment for Digital-to-Analog Converter Boxes (open access)

Energy Savings Assessment for Digital-to-Analog Converter Boxes

The Digital Television (DTV) Converter Box Coupon Program was administered by the U.S. government to subsidize purchases of digital-to-analog converter boxes, with up to two $40 coupons for each eligible household. In order to qualify as Coupon Eligible Converter Boxes (CECBs), these devices had to meet a number of minimum performance specifications, including energy efficiency standards. The Energy Star Program also established voluntary energy efficiency specifications that are more stringent than the CECB requirements. In this study, we measured the power and energy consumptions for a sample of 12 CECBs (including 6 Energy Star labeled models) in-use in homes and estimated aggregate energy savings produced by the energy efficiency policies. Based on the 35 million coupons redeemed through the end of the program, our analysis indicates that between 2500 and 3700 GWh per year are saved as a result of the energy efficiency policies implemented on digital-to-analog converter boxes. The energy savings generated are equivalent to the annual electricity use of 280,000 average US homes.
Date: January 18, 2011
Creator: Cheung, Hoi Ying Iris; Meier, Alan & Brown, Richard
System: The UNT Digital Library
Search for a Low-Mass Scalar Higgs Boson Decaying to a Tau Pair in Single-Photon Decays of Upsilon(1S) (open access)

Search for a Low-Mass Scalar Higgs Boson Decaying to a Tau Pair in Single-Photon Decays of Upsilon(1S)

None
Date: January 18, 2013
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Palano, A. et al.
System: The UNT Digital Library
A Search for Dark Matter in Events with One Jet and Missing Transverse Energy in pp-bar Collisions at sqrt(s) = 1.96 TeV (open access)

A Search for Dark Matter in Events with One Jet and Missing Transverse Energy in pp-bar Collisions at sqrt(s) = 1.96 TeV

None
Date: January 18, 2013
Creator: Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
System: The UNT Digital Library
Room-temperature Formation of Hollow Cu2O Nanoparticles (open access)

Room-temperature Formation of Hollow Cu2O Nanoparticles

Monodisperse Cu and Cu2O nanoparticles (NPs) are synthesized using tetradecylphosphonic acid as a capping agent. Dispersing the NPs in chloroform and hexane at room temperature results in the formation of hollow Cu2O NPs and Cu@Cu2O core/shell NPs, respectively. The monodisperse Cu2O NPs are used to fabricate hybrid solar cells with efficiency of 0.14percent under AM 1.5 and 1 Sun illumination.
Date: January 18, 2010
Creator: Hung, Ling-I; Tsung, Chia-Kuang; Huang, Wenyu & Yang, Peidong
System: The UNT Digital Library
Fully Coupled Geomechanics and Discrete Flow Network Modeling of Hydraulic Fracturing for Geothermal Applications (open access)

Fully Coupled Geomechanics and Discrete Flow Network Modeling of Hydraulic Fracturing for Geothermal Applications

The primary objective of our current research is to develop a computational test bed for evaluating borehole techniques to enhance fluid flow and heat transfer in enhanced geothermal systems (EGS). Simulating processes resulting in hydraulic fracturing and/or the remobilization of existing fractures, especially the interaction between propagating fractures and existing fractures, represents a critical goal of our project. To this end, we are continuing to develop a hydraulic fracturing simulation capability within the Livermore Distinct Element Code (LDEC), a combined FEM/DEM analysis code with explicit solid-fluid mechanics coupling. LDEC simulations start from an initial fracture distribution which can be stochastically generated or upscaled from the statistics of an actual fracture distribution. During the hydraulic stimulation process, LDEC tracks the propagation of fractures and other modifications to the fracture system. The output is transferred to the Non-isothermal Unsaturated Flow and Transport (NUFT) code to capture heat transfer and flow at the reservoir scale. This approach is intended to offer flexibility in the types of analyses we can perform, including evaluating the effects of different system heterogeneities on the heat extraction rate as well as seismicity associated with geothermal operations. This paper details the basic methodology of our approach. Two numerical examples …
Date: January 18, 2011
Creator: Fu, P.; Johnson, S. M.; Hao, Y. & Carrigan, C. R.
System: The UNT Digital Library
Using Tabular EOS at Low Temperatures (open access)

Using Tabular EOS at Low Temperatures

None
Date: January 18, 2013
Creator: Managan, R. A.
System: The UNT Digital Library
NEW MATERIALS DEVELOPED TO MEET REGULATORY AND TECHNICAL REQUIREMENTS ASSOCIATED WITH IN-SITU DECOMMISSIONING OF NUCLEAR REACTORS AND ASSOCIATED FACILITIES (open access)

NEW MATERIALS DEVELOPED TO MEET REGULATORY AND TECHNICAL REQUIREMENTS ASSOCIATED WITH IN-SITU DECOMMISSIONING OF NUCLEAR REACTORS AND ASSOCIATED FACILITIES

For the 2010 ANS Embedded Topical Meeting on Decommissioning, Decontamination and Reutilization and Technology, Savannah River National Laboratory's Mike Serrato reported initial information on the newly developed specialty grout materials necessary to satisfy all requirements associated with in-situ decommissioning of P-Reactor and R-Reactor at the U.S. Department of Energy's Savannah River Site. Since that report, both projects have been successfully completed and extensive test data on both fresh properties and cured properties has been gathered and analyzed for a total of almost 191,150 m{sup 3} (250,000 yd{sup 3}) of new materials placed. The focus of this paper is to describe the (1) special grout mix for filling the P-Reactor vessel (RV) and (2) the new flowable structural fill materials used to fill the below grade portions of the facilities. With a wealth of data now in hand, this paper also captures the test results and reports on the performance of these new materials. Both reactors were constructed and entered service in the early 1950s, producing weapons grade materials for the nation's defense nuclear program. R-Reactor was shut down in 1964 and the P-Reactor in 1991. In-situ decommissioning (ISD) was selected for both facilities and performed as Comprehensive Environmental Response, Compensations …
Date: January 18, 2012
Creator: Blankenship, J.; Langton, C.; Musall, J. & Griffin, W.
System: The UNT Digital Library
MIXING MODELING ANALYSIS FOR SRS SALT WASTE DISPOSITION (open access)

MIXING MODELING ANALYSIS FOR SRS SALT WASTE DISPOSITION

Nuclear waste at Savannah River Site (SRS) waste tanks consists of three different types of waste forms. They are the lighter salt solutions referred to as supernate, the precipitated salts as salt cake, and heavier fine solids as sludge. The sludge is settled on the tank floor. About half of the residual waste radioactivity is contained in the sludge, which is only about 8 percentage of the total waste volume. Mixing study to be evaluated here for the Salt Disposition Integration (SDI) project focuses on supernate preparations in waste tanks prior to transfer to the Salt Waste Processing Facility (SWPF) feed tank. The methods to mix and blend the contents of the SRS blend tanks were evalutaed to ensure that the contents are properly blended before they are transferred from the blend tank such as Tank 50H to the SWPF feed tank. The work consists of two principal objectives to investigate two different pumps. One objective is to identify a suitable pumping arrangement that will adequately blend/mix two miscible liquids to obtain a uniform composition in the tank with a minimum level of sludge solid particulate in suspension. The other is to estimate the elevation in the tank at which …
Date: January 18, 2011
Creator: Lee, S.
System: The UNT Digital Library
Studies of Nucleon Resonance Structure in Exclusive Meson Electroproduction (open access)

Studies of Nucleon Resonance Structure in Exclusive Meson Electroproduction

None
Date: January 18, 2013
Creator: Aznauryan, I. G.; Bashir, A.; Braun, V.; Brodsky, S. J.; Burkert, V. D.; Chang, L. et al.
System: The UNT Digital Library
A Low-Frequency Model for E-Field and B-Field Coupling into a Folded Antenna with Two Gaps (open access)

A Low-Frequency Model for E-Field and B-Field Coupling into a Folded Antenna with Two Gaps

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Date: January 18, 2012
Creator: Perkins, M. P.; Ong, M. M. & Robbins, C. L.
System: The UNT Digital Library
Imaging nanoscale magnetic structures with polarized soft x-ray photons (open access)

Imaging nanoscale magnetic structures with polarized soft x-ray photons

Imaging nanoscale magnetic structures and their fast dynamics is scientifically interesting and technologically of highest relevance. The combination of circularly polarized soft X-ray photons which provide a strong X-ray magnetic circular dichroism effect at characteristic X-ray absorption edges, with a high resolution soft X-ray microscope utilizing Fresnel zone plate optics allows to study in a unique way the stochastical behavior in the magnetization reversal process of thin films and the ultrafast dynamics of magnetic vortices and domain walls in confined ferromagnetic structures. Future sources of fsec short and high intense soft X-ray photon pulses hold the promise of magnetic imaging down to fundamental magnetic length and time scales.
Date: January 18, 2010
Creator: Fischer, P. & Im, M.-Y.
System: The UNT Digital Library
Extracting Scattering Phase-Shifts in Higher Partial-Waves from Lattice QCD Calculations (open access)

Extracting Scattering Phase-Shifts in Higher Partial-Waves from Lattice QCD Calculations

None
Date: January 18, 2011
Creator: Luu, T & Savage, M J
System: The UNT Digital Library