Computational and Experimental Design of Fe-Based Superalloys for Elevated-Temperature Applications (open access)

Computational and Experimental Design of Fe-Based Superalloys for Elevated-Temperature Applications

Analogous to nickel-based superalloys, Fe-based superalloys, which are strengthened by coherent B2- type precipitates are proposed for elevated-temperature applications. During the period of this project, a series of ferritic superalloys have been designed and fabricated by methods of vacuum-arc melting and vacuum-induction melting. Nano-scale precipitates were characterized by atom-probe tomography, ultrasmall- angle X-ray scattering, and transmission-electron microscopy. A duplex distribution of precipitates was found. It seems that ferritic superalloys are susceptible to brittle fracture. Systematic endeavors have been devoted to understanding and resolving the problem. Factors, such as hot rolling, precipitate volume fractions, alloy compositions, precipitate sizes and inter-particle spacings, and hyperfine cooling precipitates, have been investigated. In order to understand the underlying relationship between the microstructure and creep behavior of ferric alloys at elevated temperatures, in-situ neutron studies have been carried out. Based on the current result, it seems that the major role of β΄ with a 16%-volume fraction in strengthening ferritic alloys is not load sharing but interactions with dislocations. The oxidation behavior of one ferritic alloy, FBB8 (Fe-6.5Al-10Ni-10Cr-3.4Mo-0.25Zr-0.005B, weight percent), was studied in dry air. It is found that it possesses superior oxidation resistance at 1,023 and 1,123 K, compared with other creep-resistant ferritic steels [T91 (modified …
Date: January 14, 2012
Creator: Liaw, Peter K.; Fine, Morris E.; Ghosh, Gautam; Asta, Mark D.; Liu, Chain T.; Sun, Zhiqian et al.
Object Type: Report
System: The UNT Digital Library
Theoretical Studies on the Electronic Structures and Properties of Complex Ceramic Crystals and Novel Materials (open access)

Theoretical Studies on the Electronic Structures and Properties of Complex Ceramic Crystals and Novel Materials

This project is a continuation of a long program supported by the Office of Basic Energy Science in the Office of Science of DOE for many years. The final three-year continuation started on November 1, 2005 with additional 1 year extension to October 30, 2009. The project was then granted a two-year No Cost Extension which officially ended on October 30, 2011. This report covers the activities within this six year period with emphasis on the work completed within the last 3 years. A total of 44 papers with acknowledgement to this grant were published or submitted. The overall objectives of this project are as follows. These objectives have been evolved over the six year period: (1) To use the state-of-the-art computational methods to investigate the electronic structures of complex ceramics and other novel crystals. (2) To further investigate the defects, surfaces/interfaces and microstructures in complex materials using large scale modeling. (3) To extend the study on ceramic materials to more complex bioceramic crystals. (4) To initiate the study on soft condensed matters including water and biomolecules. (5) To focus on the spectroscopic studies of different materials especially on the ELNES and XANES spectral calculations and their applications related to …
Date: January 14, 2012
Creator: Ching, Wai-Yim
Object Type: Text
System: The UNT Digital Library
Ab-initio description of quasiparticle band structures and optical near-edge absorption of transparent conducting oxides (open access)

Ab-initio description of quasiparticle band structures and optical near-edge absorption of transparent conducting oxides

None
Date: February 14, 2012
Creator: Schleife, A & Bechstedt, F
Object Type: Article
System: The UNT Digital Library
Air-Cooled Stack Freeze Tolerance Freeze Failure Modes and Freeze Tolerance Strategies for GenDriveTM Material Handling Application Systems and Stacks Final Scientific Report (open access)

Air-Cooled Stack Freeze Tolerance Freeze Failure Modes and Freeze Tolerance Strategies for GenDriveTM Material Handling Application Systems and Stacks Final Scientific Report

Air-cooled stack technology offers the potential for a simpler system architecture (versus liquid-cooled) for applications below 4 kilowatts. The combined cooling and cathode air allows for a reduction in part count and hence a lower cost solution. However, efficient heat rejection challenges escalate as power and ambient temperature increase. For applications in ambient temperatures below freezing, the air-cooled approach has additional challenges associated with not overcooling the fuel cell stack. The focus of this project was freeze tolerance while maintaining all other stack and system requirements. Through this project, Plug Power advanced the state of the art in technology for air-cooled PEM fuel cell stacks and related GenDrive material handling application fuel cell systems. This was accomplished through a collaborative work plan to improve freeze tolerance and mitigate freeze-thaw effect failure modes within innovative material handling equipment fuel cell systems designed for use in freezer forklift applications. Freeze tolerance remains an area where additional research and understanding can help fuel cells to become commercially viable. This project evaluated both stack level and system level solutions to improve fuel cell stack freeze tolerance. At this time, the most cost effective solutions are at the system level. The freeze mitigation strategies developed …
Date: February 14, 2012
Creator: Hancock, David, W.
Object Type: Report
System: The UNT Digital Library
Assistance to Firefighters Program: Distribution of Fire Grant Funding (open access)

Assistance to Firefighters Program: Distribution of Fire Grant Funding

This report discusses the firefighting activities that are traditionally the responsibility of states and local communities. The report also talks about the funding for firefighters, which is provided mostly by state and local governments. However, during the 106th Congress, many in the fire community asserted that local fire departments require and deserve greater support from the federal government.
Date: February 14, 2012
Creator: Kruger, Lennard G.
Object Type: Report
System: The UNT Digital Library
Assistance to Firefighters Program: Distribution of Fire Grant Funding (open access)

Assistance to Firefighters Program: Distribution of Fire Grant Funding

Background of the Fire Grants Authorization Act of 2011, including its purpose and uses of funding resulting from the act.
Date: February 14, 2012
Creator: Kruger, Lennard G.
Object Type: Report
System: The UNT Digital Library
Branching Fraction Measurements of the Color-Suppressed Decays B0bar to D(*)0 pi0, D(*)0 eta, D(*)0 omega, and D(*)0 eta_prime and Measurement of the Polarization in the Decay B0bar to D*0 omega (open access)

Branching Fraction Measurements of the Color-Suppressed Decays B0bar to D(*)0 pi0, D(*)0 eta, D(*)0 omega, and D(*)0 eta_prime and Measurement of the Polarization in the Decay B0bar to D*0 omega

We report updated branching fraction measurements of the color-suppressed decays {bar B}{sup 0} {yields} D{sup 0}{pi}{sup 0}, D*{sup 0}{pi}{sup 0}, D{sup 0}{eta}, D*{sup 0}{eta}, D{sup 0}{omega}, D*{sup 0}{omega}, D{sup 0}{eta}', and D*{sup 0}{eta}'. We measure the branching fractions (x10{sup -4}): {Beta}({bar B}{sup 0} {yields} D{sup 0}{pi}{sup 0}) = 2.69 {+-} 0.09 {+-} 0.13, {Beta}({bar B}{sup 0} {yields} D*{sup 0}{pi}{sup 0}) = 3.05 {+-} 0.14 {+-} 0.28, {Beta}({bar B}{sup 0} {yields} D{sup 0}{eta}) = 2.53 {+-} 0.09 {+-} 0.11, {Beta}({bar B}{sup 0} {yields} D*{sup 0}{eta}) = 2.69 {+-} 0.14 {+-} 0.23, {Beta}({bar B}{sup 0} {yields} D{sup 0}{omega}) = 2.57 {+-} 0.11 {+-} 0.14, {Beta}({bar B}{sup 0} {yields} D*{sup 0}{omega}) = 4.55 {+-} 0.24 {+-} 0.39, {Beta}({bar B}{sup 0} {yields} D{sup 0}{eta}') = 1.48 {+-} 0.13 {+-} 0.07, and {Beta}({bar B}{sup 0} {yields} D*{sup 0}{eta}') = 1.49 {+-} 0.22 {+-} 0.15. We also present the first measurement of the longitudinal polarization fraction of the decay channel D*{sup 0}{omega}, f{sub L} = (66.5 {+-} 4.7 {+-} 1.5)%. In the above, the first uncertainty is statistical and the second is systematic. The results are based on a sample of (454 {+-} 5) x 10{sup 6} B{bar B} pairs collected at the {Upsilon}(4S) resonance, with …
Date: February 14, 2012
Creator: Lees, J. P.; Poireau, V.; Tisserand, V.; Garra Tico, J.; Grauges, E.; Martinelli, M. et al.
Object Type: Article
System: The UNT Digital Library
Composite Octet Searches with Jet Substructure (open access)

Composite Octet Searches with Jet Substructure

Many new physics models with strongly interacting sectors predict a mass hierarchy between the lightest vector meson and the lightest pseudoscalar mesons. We examine the power of jet substructure tools to extend the 7 TeV LHC sensitivity to these new states for the case of QCD octet mesons, considering both two gluon and two b-jet decay modes for the pseudoscalar mesons. We develop both a simple dijet search using only the jet mass and a more sophisticated jet substructure analysis, both of which can discover the composite octets in a dijet-like signature. The reach depends on the mass hierarchy between the vector and pseudoscalar mesons. We find that for the pseudoscalar-to-vector meson mass ratio below approximately 0.2 the simple jet mass analysis provides the best discovery limit; for a ratio between 0.2 and the QCD-like value of 0.3, the sophisticated jet substructure analysis has the best discovery potential; for a ratio above approximately 0.3, the standard four-jet analysis is more suitable.
Date: February 14, 2012
Creator: Bai, Yang & Shelton, Jessie
Object Type: Article
System: The UNT Digital Library
The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method Catalog of Galaxy Groups (open access)

The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method Catalog of Galaxy Groups

We use the first 25% of the DEEP2 Galaxy Redshift Survey spectroscopic data to identify groups and clusters of galaxies in redshift space. The data set contains 8370 galaxies with confirmed redshifts in the range 0.7 {<=} z {<=} 1.4, over one square degree on the sky. Groups are identified using an algorithm (the Voronoi-Delaunay Method) that has been shown to accurately reproduce the statistics of groups in simulated DEEP2-like samples. We optimize this algorithm for the DEEP2 survey by applying it to realistic mock galaxy catalogs and assessing the results using a stringent set of criteria for measuring group-finding success, which we develop and describe in detail here. We find in particular that the group-finder can successfully identify {approx}78% of real groups and that {approx}79% of the galaxies that are true members of groups can be identified as such. Conversely, we estimate that {approx}55% of the groups we find can be definitively identified with real groups and that {approx}46% of the galaxies we place into groups are interloper field galaxies. Most importantly, we find that it is possible to measure the distribution of groups in redshift and velocity dispersion, n({sigma}, z), to an accuracy limited by cosmic variance, for …
Date: February 14, 2012
Creator: Gerke, Brian F.; Newman, Jeffrey A.; Davis, Marc; Marinoni, Christian; Yan, Renbin; Coil, Alison L. et al.
Object Type: Article
System: The UNT Digital Library
Discretionary Budget Authority by Subfunction: An Overview (open access)

Discretionary Budget Authority by Subfunction: An Overview

President Obama's FY2013 budget submission was released on February 13, 2012. This report provides a graphical overview of historical trends in discretionary budget authority (BA) from FY1976 through FY2011, enacted levels for FY2012 spending, and the levels consistent with the President's proposals for FY2013 through FY2017. Spending caps and budget enforcement mechanisms established in the Budget Control Act (BCA) of 2011 will probably strongly affect the FY2013 budget cycle. This report may provide a starting point for discussions about spending trends and federal priorities, but it does not attempt to explain spending patterns in each policy area.
Date: February 14, 2012
Creator: Austin, D. Andrew
Object Type: Report
System: The UNT Digital Library
Evaluation of Representative Smart Grid Investment Grant Project Technologies: Distributed Generation (open access)

Evaluation of Representative Smart Grid Investment Grant Project Technologies: Distributed Generation

This document is one of a series of reports estimating the benefits of deploying technologies similar to those implemented on the Smart Grid Investment Grant (SGIG) projects. Four technical reports cover the various types of technologies deployed in the SGIG projects, distribution automation, demand response, energy storage, and renewables integration. A fifth report in the series examines the benefits of deploying these technologies on a national level. This technical report examines the impacts of addition of renewable resources- solar and wind in the distribution system as deployed in the SGIG projects.
Date: February 14, 2012
Creator: Singh, Ruchi & Vyakaranam, Bharat GNVSR
Object Type: Report
System: The UNT Digital Library
Evaluation of Representative Smart Grid Investment Grant Project Technologies: Thermal Energy Storage (open access)

Evaluation of Representative Smart Grid Investment Grant Project Technologies: Thermal Energy Storage

This document is one of a series of reports estimating the benefits of deploying technologies similar to those implemented on the Smart Grid Investment Grant (SGIG) projects. Four technical reports cover the various types of technologies deployed in the SGIG projects, distribution automation, demand response, energy storage, and renewables integration. A fifth report in the series examines the benefits of deploying these technologies on a national level. This technical report examines the impacts of energy storage technologies deployed in the SGIG projects.
Date: February 14, 2012
Creator: Tuffner, Francis K. & Bonebrake, Christopher A.
Object Type: Report
System: The UNT Digital Library
Evaluation of Representative Smart Grid Investment Project Technologies: Demand Response (open access)

Evaluation of Representative Smart Grid Investment Project Technologies: Demand Response

This document is one of a series of reports estimating the benefits of deploying technologies similar to those implemented on the Smart Grid Investment Grant (SGIG) projects. Four technical reports cover the various types of technologies deployed in the SGIG projects, distribution automation, demand response, energy storage, and renewables integration. A fifth report in the series examines the benefits of deploying these technologies on a national level. This technical report examines the impacts of a limited number of demand response technologies and implementations deployed in the SGIG projects.
Date: February 14, 2012
Creator: Fuller, Jason C.; Prakash Kumar, Nirupama & Bonebrake, Christopher A.
Object Type: Report
System: The UNT Digital Library
Extending the Temporary Payroll Tax Reduction: A Brief Description and Economic Analysis (open access)

Extending the Temporary Payroll Tax Reduction: A Brief Description and Economic Analysis

This report briefly discusses economic stimulus considerations related to temporary payroll tax reductions. In addition, as the Social Security trust fund is made whole through a transfer from the general fund, select options to offset this increase in the deficit will be examined to illustrate how the choice offsets can affect the net amount of economic stimulus provided.
Date: February 14, 2012
Creator: Marples, Donald J. & Sherlock, Molly F.
Object Type: Report
System: The UNT Digital Library
Federal Employees' Retirement System: Benefits and Financing (open access)

Federal Employees' Retirement System: Benefits and Financing

Most civilian federal employees who were hired before 1984 are covered by the Civil Service Retirement System, and contribute 7.0% of their pay to a retirement fund. Federal employees hired in 1984 or later are covered by the Federal Employees' Retirement System and contribute 0.8% of their pay to a retirement fund. Both require participants to contribute toward the cost of their pensions through a payroll tax. The taxable wage base is $110,100 in 2012. This report discusses both retirement funds.
Date: February 14, 2012
Creator: Isaacs, Katelin P.
Object Type: Report
System: The UNT Digital Library
Focus Report, Volume 82, Number 2, February 14, 2011 (open access)

Focus Report, Volume 82, Number 2, February 14, 2011

"This report summarizes the key constitutional provisions and rules governing bills in the Legislature, with emphasis on House rules."
Date: February 14, 2012
Creator: Texas. Legislature. House of Representatives. Research Organization.
Object Type: Journal/Magazine/Newsletter
System: The Portal to Texas History
Integrated genome-based studies of Shewanella ecophysiology (open access)

Integrated genome-based studies of Shewanella ecophysiology

This project was a component of the Shewanella Federation and, as such, contributed to the overall goal of applying the genomic tools to better understand eco-physiology and speciation of respiratory-versatile members of Shewanella genus. Our role at Boston University was to perform bioreactor and high throughput gene expression microarrays, and combine dynamic flux balance modeling with experimentally obtained transcriptional and gene expression datasets from different growth conditions. In the first part of project, we designed the S. oneidensis microarray probes for Affymetrix Inc. (based in California), then we identified the pathways of carbon utilization in the metal-reducing marine bacterium Shewanella oneidensis MR-1, using our newly designed high-density oligonucleotide Affymetrix microarray on Shewanella cells grown with various carbon sources. Next, using a combination of experimental and computational approaches, we built algorithm and methods to integrate the transcriptional and metabolic regulatory networks of S. oneidensis. Specifically, we combined mRNA microarray and metabolite measurements with statistical inference and dynamic flux balance analysis (dFBA) to study the transcriptional response of S. oneidensis MR-1 as it passes through exponential, stationary, and transition phases. By measuring time-dependent mRNA expression levels during batch growth of S. oneidensis MR-1 under two radically different nutrient compositions (minimal lactate and …
Date: February 14, 2012
Creator: Daniel, Segre & Qasim, Beg
Object Type: Report
System: The UNT Digital Library
Latin America and the Caribbean: U.S. Policy and Key Issues for Congress in 2012 (open access)

Latin America and the Caribbean: U.S. Policy and Key Issues for Congress in 2012

This report provides an overview of U.S. policy toward Latin America and the Caribbean, including the Obama Administration's priorities for U.S. policy and a brief comparison of policies under the Obama and Bush Administrations. It then examines congressional interest in Latin America, first providing an overview, and then looking at selected countries and regional issues and identifying key policy issues facing Congress in 2012. The final section of the report analyzes several upcoming events in the region in 2012 that could have an impact on developments in several countries or on U.S. relations with the region.
Date: February 14, 2012
Creator: Sullivan, Mark P.; Beittel, June S.; Leland, Anne; Meyer, Peter J.; Ribando Seelke, Clare & Taft-Morales, Maureen
Object Type: Report
System: The UNT Digital Library
Latin America and the Caribbean: U.S. Policy and Key Issues for Congress in 2012 (open access)

Latin America and the Caribbean: U.S. Policy and Key Issues for Congress in 2012

This report provides an overview of U.S. policy toward Latin America and the Caribbean, including the Obama Administration's priorities for U.S. policy and a brief comparison of policies under the Obama and Bush Administrations. It then examines congressional interest in Latin America, first providing an overview, and then looking at selected countries and regional issues and identifying key policy issues facing Congress in 2012. The final section of the report analyzes several upcoming events in the region in 2012 that could have an impact on developments in several countries or on U.S. relations with the region.
Date: February 14, 2012
Creator: Sullivan, Mark P.; Beittel, June S.; Leland, Anne; Seelke, Clare Ribando & Taft-Morales, Maureen
Object Type: Report
System: The UNT Digital Library
Low-Dimensional Water on Ru(0001)Model System for X-ray Absorption Spectroscopy Studies of Liquid Water (open access)

Low-Dimensional Water on Ru(0001)Model System for X-ray Absorption Spectroscopy Studies of Liquid Water

We present an x-ray absorption spectroscopy results for fully broken to a complete H-bond network of water molecules on Ru(0001) by varying the morphology from isolated water molecules via two-dimensional clusters to a fully covered monolayer as probed by scanning tunneling microscopy. The sensitivity of x-ray absorption to the symmetry of H-bonding is further elucidated for the amino (-NH{sub 2}) group in glycine adsorbed on Cu(110) where the E-vector is parallel either to the NH donating an H-bond or to the non-H-bonded NH. The results give further evidence for the interpretation of the various spectral features of liquid water and for the general applicability of x-ray absorption spectroscopy to analyze H-bonded systems.
Date: February 14, 2012
Creator: Nordlund, D.
Object Type: Article
System: The UNT Digital Library
Magnetorotational Turbulence Transports Angular Momentum in Stratified Disks with Low Magnetic Prandtl Number but Magnetic Reynolds Number above a Critical Value (open access)

Magnetorotational Turbulence Transports Angular Momentum in Stratified Disks with Low Magnetic Prandtl Number but Magnetic Reynolds Number above a Critical Value

The magnetorotational instability (MRI) may dominate outward transport of angular momentum in accretion disks, allowing material to fall onto the central object. Previous work has established that the MRI can drive a mean-field dynamo, possibly leading to a self-sustaining accretion system. Recently, however, simulations of the scaling of the angular momentum transport parameter {alpha}{sub SS} with the magnetic Prandtl number Pm have cast doubt on the ability of the MRI to transport astrophysically relevant amounts of angular momentum in real disk systems. Here, we use simulations including explicit physical viscosity and resistivity to show that when vertical stratification is included, mean field dynamo action operates, driving the system to a configuration in which the magnetic field is not fully helical. This relaxes the constraints on the generated field provided by magnetic helicity conservation, allowing the generation of a mean field on timescales independent of the resistivity. Our models demonstrate the existence of a critical magnetic Reynolds number Rm{sub crit}, below which transport becomes strongly Pm-dependent and chaotic, but above which the transport is steady and Pm-independent. Prior simulations showing Pm-dependence had Rm < Rm{sub crit}. We conjecture that this steady regime is possible because the mean field dynamo is not …
Date: February 14, 2012
Creator: Oishi, Jeffrey S.; /KIPAC, Menlo Park; Low, Mordecai-Mark Mac & Hist., /Amer. Museum Natural
Object Type: Article
System: The UNT Digital Library
NARAC Modeling During the Response to the Fukushima Dai-ichi Nuclear Power Plant Emergency (open access)

NARAC Modeling During the Response to the Fukushima Dai-ichi Nuclear Power Plant Emergency

This paper summarizes the activities of the National Atmospheric Release Advisory Center (NARAC) during the Fukushima Dai-ichi nuclear power plant crisis. NARAC provided a wide range of products and analyses as part of its support including: (1) Daily Japanese weather forecasts and hypothetical release (generic source term) dispersion predictions to provide situational awareness and inform planning for U.S. measurement data collection and field operations; (2) Estimates of potential dose in Japan for hypothetical scenarios developed by the Nuclear Regulatory Commission (NRC) to inform federal government considerations of possible actions that might be needed to protect U.S. citizens in Japan; (3) Estimates of possible plume arrival times and dose for U.S. locations; and (4) Plume model refinement and source estimation based on meteorological analyses and available field data. The Department of Energy/National Nuclear Security Administration (DOE/NNSA) deployed personnel to Japan and stood up 'home team' assets across the DOE complex to aid in assessing the consequences of the releases from the Fukushima Dai-ichi Nuclear Power Plant. The DOE Nuclear Incident Team (NIT) coordinated response activities, while DOE personnel provided predictive modeling, air and ground monitoring, sample collection, laboratory analysis, and data assessment and interpretation. DOE deployed the Aerial Measuring System (AMS), …
Date: February 14, 2012
Creator: Sugiyama, G.; Nasstrom, J. S.; Probanz, B.; Foster, K. T.; Simpson, M.; Vogt, P. et al.
Object Type: Article
System: The UNT Digital Library
A Natural Language for AdS/CFT Correlators (open access)

A Natural Language for AdS/CFT Correlators

We provide dramatic evidence that 'Mellin space' is the natural home for correlation functions in CFTs with weakly coupled bulk duals. In Mellin space, CFT correlators have poles corresponding to an OPE decomposition into 'left' and 'right' sub-correlators, in direct analogy with the factorization channels of scattering amplitudes. In the regime where these correlators can be computed by tree level Witten diagrams in AdS, we derive an explicit formula for the residues of Mellin amplitudes at the corresponding factorization poles, and we use the conformal Casimir to show that these amplitudes obey algebraic finite difference equations. By analyzing the recursive structure of our factorization formula we obtain simple diagrammatic rules for the construction of Mellin amplitudes corresponding to tree-level Witten diagrams in any bulk scalar theory. We prove the diagrammatic rules using our finite difference equations. Finally, we show that our factorization formula and our diagrammatic rules morph into the flat space S-Matrix of the bulk theory, reproducing the usual Feynman rules, when we take the flat space limit of AdS/CFT. Throughout we emphasize a deep analogy with the properties of flat space scattering amplitudes in momentum space, which suggests that the Mellin amplitude may provide a holographic definition of …
Date: February 14, 2012
Creator: Fitzpatrick, A. Liam; Kaplan, Jared; Penedones, Joao; Raju, Suvrat & van Rees, Balt C.
Object Type: Article
System: The UNT Digital Library
The New START Treaty: Central Limits and Key Provisions (open access)

The New START Treaty: Central Limits and Key Provisions

The United States and Russia signed a new strategic arms reduction treaty - known as New START - on April 8, 2010. This treaty is designed to replace the 1991 Strategic Arms Reductions Treaty (START), which expired, after 15 years of implementation, on December 5, 2009. This report provides an overview of New START, including a comparison to the original START Treaty, the belief of the Obama Administration and outside analysts that New START will enhance U.S. national security, and the criticisms of those who say that New START (and, indeed, the entire issue of U.S.-Russian arms control) is a distraction from more important items on the nonproliferation agenda.
Date: February 14, 2012
Creator: Woolf, Amy F.
Object Type: Report
System: The UNT Digital Library