Radiative forcing and temperature response to changes in urban albedos and associated CO2 offsets (open access)

Radiative forcing and temperature response to changes in urban albedos and associated CO2 offsets

The two main forcings that can counteract to some extent the positive forcings from greenhouse gases from pre-industrial times to present-day are the aerosol and related aerosol-cloud forcings, and the radiative response to changes in surface albedo. Here, we quantify the change in radiative forcing and land surface temperature that may be obtained by increasing the albedos of roofs and pavements in urban areas in temperate and tropical regions of the globe by 0.1. Using the catchment land surface model (the land model coupled to the GEOS-5 Atmospheric General Circulation Model), we quantify the change in the total outgoing (outgoing shortwave+longwave) radiation and land surface temperature to a 0.1 increase in urban albedos for all global land areas. The global average increase in the total outgoing radiation was 0.5 Wm{sup -2}, and temperature decreased by {approx}0.008 K for an average 0.003 increase in surface albedo. These averages represent all global land areas where data were available from the land surface model used and are for the boreal summer (June-July-August). For the continental U.S. the total outgoing radiation increased by 2.3 Wm{sup -2}, and land surface temperature decreased by {approx}0.03 K for an average 0.01 increase in surface albedo. Based on …
Date: February 12, 2010
Creator: Menon, Surabi; Akbari, Hashem; Mahanama, Sarith; Sednev, Igor & Levinson, Ronnen
Object Type: Article
System: The UNT Digital Library
Secondary Startup Neutron Sources as a Source of Tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS) (open access)

Secondary Startup Neutron Sources as a Source of Tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS)

The hypothesis of this paper is that the Zircaloy clad fuel source is minimal and that secondary startup neutron sources are the significant contributors of the tritium in the RCS that was previously assigned to release from fuel. Currently there are large uncertainties in the attribution of tritium in a Pressurized Water Reactor (PWR) Reactor Coolant System (RCS). The measured amount of tritium in the coolant cannot be separated out empirically into its individual sources. Therefore, to quantify individual contributors, all sources of tritium in the RCS of a PWR must be understood theoretically and verified by the sum of the individual components equaling the measured values.
Date: February 1, 2010
Creator: Shaver, Mark W. & Lanning, Donald D.
Object Type: Report
System: The UNT Digital Library
Mitigation of cache memory using an embedded hard-core PPC440 processor in a Virtex-5 Field Programmable Gate Array. (open access)

Mitigation of cache memory using an embedded hard-core PPC440 processor in a Virtex-5 Field Programmable Gate Array.

Sandia National Laboratories is currently developing new processing and data communication architectures for use in future satellite payloads. These architectures will leverage the flexibility and performance of state-of-the-art static-random-access-memory-based Field Programmable Gate Arrays (FPGAs). One such FPGA is the radiation-hardened version of the Virtex-5 being developed by Xilinx. However, not all features of this FPGA are being radiation-hardened by design and could still be susceptible to on-orbit upsets. One such feature is the embedded hard-core PPC440 processor. Since this processor is implemented in the FPGA as a hard-core, traditional mitigation approaches such as Triple Modular Redundancy (TMR) are not available to improve the processor's on-orbit reliability. The goal of this work is to investigate techniques that can help mitigate the embedded hard-core PPC440 processor within the Virtex-5 FPGA other than TMR. Implementing various mitigation schemes reliably within the PPC440 offers a powerful reconfigurable computing resource to these node-based processing architectures. This document summarizes the work done on the cache mitigation scheme for the embedded hard-core PPC440 processor within the Virtex-5 FPGAs, and describes in detail the design of the cache mitigation scheme and the testing conducted at the radiation effects facility on the Texas A&M campus.
Date: February 1, 2010
Creator: Learn, Mark Walter
Object Type: Report
System: The UNT Digital Library
EUV pattern defect detection sensitivity based on aerial image linewidth measurements (open access)

EUV pattern defect detection sensitivity based on aerial image linewidth measurements

As the quality of EUV-wavelength mask inspection microscopes improves over time, the image properties and intensity profiles of reflected light can be evaluated in ever-greater detail. The SEMATECH Berkeley Actinic Inspection Tool (AIT) is one such microscope, featuring mask resolution values that match or exceed those available through lithographic printing in current photoresists. In order to evaluate the defect detection sensitivity of the AIT for dense line patterns on typical masks, the authors study the line width roughness (LWR) on two masks, as measured in the EUV images. They report the through-focus and pitch dependence of contrast, image log slope, linewidth, and LWR. The AIT currently reaches LWR 3{sigma} values close to 9 nm for 175 nm half-pitch lines. This value is below 10% linewidth for nearly all lines routinely measured in the AIT. Evidence suggests that this lower level may arise from the mask's inherent pattern roughness. While the sensitivity limit of the AlT has not yet been established, it is clear that the AIT has the required sensitivity to detect defects that cause 10% linewidth changes in line sizes of 125 nm and larger.
Date: February 12, 2010
Creator: Goldberg, K. A.; Mochi, I.; Naulleau, P.; Liang, T.; Yan, P.-Y. & Huh, S.
Object Type: Article
System: The UNT Digital Library
Discovery, SAR, and Radiolabeling of Halogenated Benzimidazole Carboxamide Antagonists as Useful Tools for (alpha)4(beta)1 Integrin Expressed on T- and B-cell Lymphomas (open access)

Discovery, SAR, and Radiolabeling of Halogenated Benzimidazole Carboxamide Antagonists as Useful Tools for (alpha)4(beta)1 Integrin Expressed on T- and B-cell Lymphomas

The cell surface receptor {alpha}{sub 4}{beta}{sub 1} integrin is an attractive yet poorly understood target for selective diagnosis and treatment of T- and B-cell lymphomas. This report focuses on the rapid microwave preparation of medicinally pertinent benzimidazole heterocycles, structure-activity relationships (SAR) of novel halobenzimidazole carboxamide antagonists 3-6, and preliminary biological evaluation of radioiodinated agents 7, 8, and 18. The I-125 derivative 18 had good tumor uptake (12 {+-} 1% ID/g at 24 h; 4.5 {+-} 1% ID/g at 48 h) and tumor:kidney ratio ({approx}4:1 at 24 h; 2.5:1 at 48 h) in xenograft murine models of B-cell lymphoma. Molecular homology models of {alpha}{sub 4}{beta}{sub 1} integrin have predicted that docked halobenzimidazole carboxamides have the halogen atom in a suitable orientation for halogen-hydrogen bonding. These high affinity ({approx} pM binding) halogenated ligands are attractive tools for medicinal and biological use; the fluoro and iodo derivatives are potential radiodiagnostic ({sup 18}F) or radiotherapeutic ({sup 131}I) agents, whereas the chloro and bromo analogues could provide structural insight into integrin-ligand interactions through photoaffinity cross-linking/mass spectroscopy experiments, as well as co-crystallization X-ray studies.
Date: February 8, 2010
Creator: Carpenter, R. D.; Natarajan, A.; Lau, E. Y.; Andrei, M.; Solano, D. M.; Lightstone, F. C. et al.
Object Type: Article
System: The UNT Digital Library
Room temperature reaction of oxygen with gold: an in situ ambient-pressure X-ray photoelectron spectroscopy investigation (open access)

Room temperature reaction of oxygen with gold: an in situ ambient-pressure X-ray photoelectron spectroscopy investigation

Gold is commonly regarded as the most inert element.1 However, the discovery of the exceptional catalytic properties of gold nanoparticles (NPs) for low temperature CO oxidation2 initiated great interest due to its promising applications and spawned a large number of studies devoted to the understanding of the reaction mechanism.3-6 Nevertheless, no consistent and conclusive picture has arisen.7-13
Date: February 1, 2010
Creator: Jiang, Peng; Porsgaard, Soeren; Borondics, Ferenc; Kober, Mariana; Caballero, Alfonso; Bluhm, Hendrik et al.
Object Type: Article
System: The UNT Digital Library
Effect of NiO spin orientation on the magnetic anisotropy of the Fe film in epitaxially grown Fe/NiO/Ag(001) and Fe/NiO/MgO(001) (open access)

Effect of NiO spin orientation on the magnetic anisotropy of the Fe film in epitaxially grown Fe/NiO/Ag(001) and Fe/NiO/MgO(001)

Single crystalline Fe/NiO bilayers were epitaxially grown on Ag(001) and on MgO(001), and investigated by Low Energy Electron Diffraction (LEED), Magneto-Optic Kerr Effect (MOKE), and X-ray Magnetic Linear Dichroism (XMLD). We find that while the Fe film has an in-plane magnetization in both Fe/NiO/Ag(001) and Fe/NiO/MgO(001) systems, the NiO spin orientation changes from in-plane direction in Fe/NiO/Ag(001) to out-of-plane direction in Fe/NiO/MgO(001). These two different NiO spin orientations generate remarkable different effects that the NiO induced magnetic anisotropy in the Fe film is much greater in Fe/NiO/Ag(001) than in Fe/NiO/MgO(001). XMLD measurement shows that the much greater magnetic anisotropy in Fe/NiO/Ag(001) is due to a 90{sup o}-coupling between the in-plane NiO spins and the in-plane Fe spins.
Date: February 10, 2010
Creator: Kim, W.; Jin, E.; Wu, J.; Park, J.; Arenholz, E.; Scholl, A. et al.
Object Type: Article
System: The UNT Digital Library
Reactivity of Biogenic Manganese Oxide for Metal Sequestration and Photochemistry: Computational Solid State Physics Study (open access)

Reactivity of Biogenic Manganese Oxide for Metal Sequestration and Photochemistry: Computational Solid State Physics Study

Many microbes, including both bacteria and fungi, produce manganese (Mn) oxides by oxidizing soluble Mn(II) to form insoluble Mn(IV) oxide minerals, a kinetically much faster process than abiotic oxidation. These biogenic Mn oxides drive the Mn cycle, coupling it with diverse biogeochemical cycles and determining the bioavailability of environmental contaminants, mainly through strong adsorption and redox reactions. This mini review introduces recent findings based on quantum mechanical density functional theory that reveal the detailed mechanisms of toxic metal adsorption at Mn oxide surfaces and the remarkable role of Mn vacancies in the photochemistry of these minerals.
Date: February 1, 2010
Creator: Kwon, K.D. & Sposito, G.
Object Type: Article
System: The UNT Digital Library
Search for the Standard Model Higgs Boson in the $WH \to \ell \nu b\bar{b}$ Channel in 1.96-TeV Proton-Antiproton Collisions (open access)

Search for the Standard Model Higgs Boson in the $WH \to \ell \nu b\bar{b}$ Channel in 1.96-TeV Proton-Antiproton Collisions

We have searched for the Standard Model Higgs boson in the WH → lvbb channel in 1.96 TeV pp collisions at CDF. This search is based on the data collected by March 2009, corresponding to an integrated luminosity of 4.3 fb<sup>-1</sup>. The W H channel is one of the most promising channels for the Higgs boson search at Tevatron in the low Higgs boson mass region.
Date: February 1, 2010
Creator: Nagai, Yoshikazu
Object Type: Thesis or Dissertation
System: The UNT Digital Library
CgWind: A high-order accurate simulation tool for wind turbines and wind farms (open access)

CgWind: A high-order accurate simulation tool for wind turbines and wind farms

CgWind is a high-fidelity large eddy simulation (LES) tool designed to meet the modeling needs of wind turbine and wind park engineers. This tool combines several advanced computational technologies in order to model accurately the complex and dynamic nature of wind energy applications. The composite grid approach provides high-quality structured grids for the efficient implementation of high-order accurate discretizations of the incompressible Navier-Stokes equations. Composite grids also provide a natural mechanism for modeling bodies in relative motion and complex geometry. Advanced algorithms such as matrix-free multigrid, compact discretizations and approximate factorization will allow CgWind to perform highly resolved calculations efficiently on a wide class of computing resources. Also in development are nonlinear LES subgrid-scale models required to simulate the many interacting scales present in large wind turbine applications. This paper outlines our approach, the current status of CgWind and future development plans.
Date: February 22, 2010
Creator: Chand, K K; Henshaw, W D; Lundquist, K A & Singer, M A
Object Type: Article
System: The UNT Digital Library
Initial Assessment of Electron and X-Ray Production and Charge Exchange in the NDCX-II Accelerator (open access)

Initial Assessment of Electron and X-Ray Production and Charge Exchange in the NDCX-II Accelerator

The purpose of this note is to provide initial assessments of some atomic physics effects for the accelerator section of NDCX-II. There are several effects we address: the production of electrons associated with loss of beam ions to the walls, the production of electrons associated with ionization of background gas, the possibly resultant production of X-rays when these electrons hit bounding surfaces, and charge exchange of beam ions on background gas. The results presented here are based on a number of caveats that will be stated below, which we will attempt to remove in the near future.
Date: February 18, 2010
Creator: Cohen, R. H.
Object Type: Report
System: The UNT Digital Library
Fresh Water Generation from Aquifer-Pressured Carbon Storage (open access)

Fresh Water Generation from Aquifer-Pressured Carbon Storage

Can we use the pressure associated with sequestration to make brine into fresh water? This project is establishing the potential for using brine pressurized by Carbon Capture and Storage (CCS) operations in saline formations as the feedstock for desalination and water treatment technologies including reverse osmosis (RO) and nanofiltration (NF). Possible products are: Drinking water, Cooling water, and Extra aquifer space for CO{sub 2} storage. The conclusions are: (1) Many saline formation waters appear to be amenable to largely conventional RO treatment; (2) Thermodynamic modeling indicates that osmotic pressure is more limiting on water recovery than mineral scaling; (3) The use of thermodynamic modeling with Pitzer's equations (or Extended UNIQUAC) allows accurate estimation of osmotic pressure limits; (4) A general categorization of treatment feasibility is based on TDS has been proposed, in which brines with 10,000-85,000 mg/L are the most attractive targets; (5) Brines in this TDS range appear to be abundant (geographically and with depth) and could be targeted in planning future CCS operations (including site selection and choice of injection formation); and (6) The estimated cost of treating waters in the 10,000-85,000 mg/L TDS range is about half that for conventional seawater desalination, due to the anticipated pressure …
Date: February 19, 2010
Creator: Aines, R. D.; Wolery, T. J.; Bourcier, W. L.; Wolfe, T. & Haussmann, C.
Object Type: Article
System: The UNT Digital Library
Partial Defect Verification of the Pressurized Water Reactor Spent Fuel Assemblies (open access)

Partial Defect Verification of the Pressurized Water Reactor Spent Fuel Assemblies

The International Atomic Energy Agency (IAEA) has the responsibility to carry out independent inspections of all nuclear material and facilities subject to safeguards agreements in order to verify compliance with non-proliferation commitments. New technologies have been continuously explored by the IAEA and Member States to improve the verification measures to account for declared inventory of nuclear material and detect clandestine diversion and production of nuclear materials. Even with these efforts, a technical safeguards challenge has remained for decades for the case of developing a method in identifying possible diversion of nuclear fuel pins from the Light Water Reactor (LWR) spent fuel assemblies. We had embarked on this challenging task and successfully developed a novel methodology in detecting partial removal of fuel from pressurized water reactor spent fuel assemblies. The methodology uses multiple tiny neutron and gamma detectors in the form of a cluster and a high precision driving system to obtain underwater radiation measurements inside a Pressurized Water Reactor (PWR) spent fuel assembly without any movement of the fuel. The data obtained in such a manner can provide spatial distribution of neutron and gamma flux within a spent fuel assembly. The combined information of gamma and neutron signature is used …
Date: February 5, 2010
Creator: Ham, Young S. & Sitaraman, Shivakumar
Object Type: Article
System: The UNT Digital Library
Development of a biomarker for Geobacter activity and strain composition: Proteogenomic analysis of the citrate synthase protein during bioremediation of U(VI) (open access)

Development of a biomarker for Geobacter activity and strain composition: Proteogenomic analysis of the citrate synthase protein during bioremediation of U(VI)

Monitoring the activity of target microorganisms during stimulated bioremediation is a key problem for the development of effective remediation strategies. At the US Department of Energy's Integrated Field Research Challenge (IFRC) site in Rifle, CO, the stimulation of Geobacter growth and activity via subsurface acetate addition leads to precipitation of U(VI) from groundwater as U(IV). Citrate synthase (gltA) is a key enzyme in Geobacter central metabolism that controls flux into the TCA cycle. Here, we utilize shotgun proteomic methods to demonstrate that the measurement of gltA peptides can be used to track Geobacter activity and strain evolution during in situ biostimulation. Abundances of conserved gltA peptides tracked Fe(III) reduction and changes in U(VI) concentrations during biostimulation, whereas changing patterns of unique peptide abundances between samples suggested sample-specific strain shifts within the Geobacter population. Abundances of unique peptides indicated potential differences at the strain level between Fe(III)-reducing populations stimulated during in situ biostimulation experiments conducted a year apart at the Rifle IFRC. These results offer a novel technique for the rapid screening of large numbers of proteomic samples for Geobacter species and will aid monitoring of subsurface bioremediation efforts that rely on metal reduction for desired outcomes.
Date: February 15, 2010
Creator: Wilkins, Michael J.; Callister, Stephen J.; Miletto, Marzia; Williams, Kenneth H.; Nicora, Carrie D.; Lovley, Derek R. et al.
Object Type: Article
System: The UNT Digital Library
[Project Summary: Platform Recruited Reef Fish, Phase 1: Do Platforms Provide Habitat That Increase the Survival of Juvenile Reef Fishes?] (open access)

[Project Summary: Platform Recruited Reef Fish, Phase 1: Do Platforms Provide Habitat That Increase the Survival of Juvenile Reef Fishes?]

Summary describing the work completed at Louisiana State University (Baton Rouge, La.). Coastal Studies Institute. for a study involving platform recruited reef fish. It includes background information on the project funding and sponsorship, goals, methodology, and findings.
Date: February 2010
Creator: Louisiana State University (Baton Rouge, La.). Coastal Studies Institute.
Object Type: Text
System: The UNT Digital Library
Proof of Concept for Platform Recruited Fish, Phase I: Do Platforms Provide Habit for Subadult Red Snapper? (open access)

Proof of Concept for Platform Recruited Fish, Phase I: Do Platforms Provide Habit for Subadult Red Snapper?

"The objective of this study was to determine if a trace element isotope ratio fingerprint could be detected and described as unique to red snapper inhabiting the platforms."
Date: February 2010
Creator: Nowling, Lauren K.; Cowen, James H., Jr. & Shaw, Richard F.
Object Type: Text
System: The UNT Digital Library
NOAA FY 2011 Budget Summary (open access)

NOAA FY 2011 Budget Summary

This report summarizes NOAA's budget request for the 2011 fiscal year.
Date: February 9, 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
The United States National Climate Assessment (open access)

The United States National Climate Assessment

This document pertains to climate change and developing a strategic plan for protecting the environment.
Date: February 2010
Creator: National Climate Assessment Strategic Planning Workshop
Object Type: Report
System: The UNT Digital Library
Quadrennial Homeland Security Review Report (open access)

Quadrennial Homeland Security Review Report

This report addresses international threats and the framework for the homeland security's strategic response.
Date: February 2010
Creator: United States. Department of Homeland Security.
Object Type: Report
System: The UNT Digital Library
Quadrennial Defense Review Report (open access)

Quadrennial Defense Review Report

"This Quadrennial Defense Review represents an important step toward fully institutionalizing the ongoing reform and reshaping of America's military."
Date: February 2010
Creator: United States. Department of Defense
Object Type: Text
System: The UNT Digital Library
Clean Air Status and Trends Network Annual Report: 2008 (open access)

Clean Air Status and Trends Network Annual Report: 2008

Annual report of the Clean Air Status and Trends Network (CASTNET) describing the program and data collection. It also presents information on air quality and recorded concentrations of pollutants such as ozone, sulfur, gases, and other elements of concern.
Date: February 2010
Creator: MACTEC Engineering and Consulting, Inc.
Object Type: Report
System: The UNT Digital Library
Customer Incentives for Energy Efficiency Through Program Offerings (open access)

Customer Incentives for Energy Efficiency Through Program Offerings

"This brief summarizes the approaches used by energy efficiency program administrators when assessing incentives to be used in energy efficiency programs."
Date: February 2010
Creator: unknown
Object Type: Text
System: The UNT Digital Library
Customer Incentives for Energy Efficiency Through Program Offerings (open access)

Customer Incentives for Energy Efficiency Through Program Offerings

This is a brief to summarize the approaches used by energy efficiency program adminstrators when assessing incentives to be used in energy efficiency programs (p. 1, para. 1).
Date: February 2010
Creator: Prindle, William
Object Type: Text
System: The UNT Digital Library
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Soft Electron b-Tagging (open access)

Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Soft Electron b-Tagging

We present a measurement of the top quark pair production cross section in p{bar p} collisions at {radical}s = 1.96 TeV using a data sample corresponding to 1.7 fb{sup -1} of integrated luminosity collected with the Collider Detector at Fermilab. We reconstruct t{bar t} events in the lepton+jets channel, consisting of e{nu}+jets and {mu}{nu}+jets final states. The dominant background is the production of W bosons in association with multiple jets. To suppress this background, we identify electrons from the semileptonic decay of heavy-flavor jets ('soft electron tags'). From a sample of 2196 candidate events, we obtain 120 tagged events with a background expectation of 51 {+-} 3 events, corresponding to a cross section of {sigma}{sub t{bar t}} = 7.8 {+-} 2.4 (stat) {+-} 1.6 (syst) {+-} 0.5 (lumi) pb. We assume a top-quark mass of 175 GeV/c{sup 2}. This is the first measurement of the t{bar t} cross section with soft electron tags in Run II of the Tevatron.
Date: February 1, 2010
Creator: Aaltonen, T.; Adelman, J.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D. et al.
Object Type: Article
System: The UNT Digital Library