Assessment of Embrittlement of VHTR Structural Alloys in Impure Helium Environments (open access)

Assessment of Embrittlement of VHTR Structural Alloys in Impure Helium Environments

The helium coolant in high-temperature reactors inevitably contains low levels of impurities during steady-state operation, primarily consisting of small amounts of H{sub 2}, H{sub 2}O, CH{sub 4}, CO, CO{sub 2}, and N{sub 2} from a variety of sources in the reactor circuit. These impurities are problematic because they can cause significant long-term corrosion in the structural alloys used in the heat exchangers at elevated temperatures. Currently, the primary candidate materials for intermediate heat exchangers are Alloy 617, Haynes 230, Alloy 800H, and Hastelloy X. This project will evaluate the role of impurities in helium coolant on the stress-assisted grain boundary oxidation and creep crack growth in candidate alloys at elevated temperatures. The project team will: • Evaluate stress-assisted grain boundary oxidation and creep crack initiation and crack growth in the temperature range of 500-850°C in a prototypical helium environment. • Evaluate the effects of oxygen partial pressure on stress-assisted grain boundary oxidation and creep crack growth in impure helium at 500°C, 700°C, and 850°C respectively. • Characterize the microstructure of candidate alloys after long-term exposure to an impure helium environment in order to understand the correlation between stress-assisted grain boundary oxidation, creep crack growth, material composition, and impurities in the …
Date: May 31, 2013
Creator: Crone, Wendy; Cao, Guoping & Sridhara, Kumar
Object Type: Report
System: The UNT Digital Library
B0 Meson Decays to Rho0 K*0, F0 K*0, And Rho- K* , Including Higher K* Resonances (open access)

B0 Meson Decays to Rho0 K*0, F0 K*0, And Rho- K* , Including Higher K* Resonances

None
Date: May 31, 2013
Creator: Lee-Boehm, Corry Louise & U., /Harvard
Object Type: Article
System: The UNT Digital Library
Budget Control Act: Potential Impact of Sequestration on Health Reform Spending (open access)

Budget Control Act: Potential Impact of Sequestration on Health Reform Spending

This report examines how automatic spending reductions triggered by the Budget Control Act (BCA) might affect health reform appropriations acts.
Date: May 31, 2013
Creator: Redhead, C. Stephen
Object Type: Report
System: The UNT Digital Library
Central Asia: Regional Developments and Implications for U.S. Interests (open access)

Central Asia: Regional Developments and Implications for U.S. Interests

Report that discusses the current status of Central Asian states and U.S. policy, which has been aimed at facilitating their cooperation with U.S. and NATO stabilization efforts in Afghanistan and their efforts to combat terrorism, proliferation, and trafficking in arms, drugs, and persons.
Date: May 31, 2013
Creator: Nichol, Jim
Object Type: Report
System: The UNT Digital Library
Climate Change: Various Adaptation Efforts Are Under Way at Key Natural Resource Management Agencies (open access)

Climate Change: Various Adaptation Efforts Are Under Way at Key Natural Resource Management Agencies

A letter report issued by the Government Accountability Office with an abstract that begins "Since 2007, the Forest Service, the National Oceanic and Atmospheric Administration (NOAA), the Fish and Wildlife Service, and the National Park Service have taken steps to establish strategic directions for addressing climate change adaptation. For example, the Forest Service developed a strategic framework document that established climate change adaptation as a central agency priority and another document, known as "the roadmap," which identified actions that national forest managers were taking or could take to implement the direction outlined in the framework, including re-vegetating ecosystems that had been affected by fire with plant species that are better adapted to current and future climates. These four agencies have also developed guidance, training, and other tools for managers to use in adapting to climate change. For example, the National Park Service is developing guidance for park-based climate change adaptation plans that includes steps such as identifying conservation targets and conducting vulnerability assessments. The Bureau of Land Management has not established a strategic direction for addressing climate change impacts but is planning to develop a high-level climate change adaptation strategy by the end of the summer 2013. In addition, GAO …
Date: May 31, 2013
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
CO{sub 2} Geologic Storage: Coupled Hydro-Chemo-Thermo-Mechanical Phenomena - From Pore-scale Processes to Macroscale Implications - (open access)

CO{sub 2} Geologic Storage: Coupled Hydro-Chemo-Thermo-Mechanical Phenomena - From Pore-scale Processes to Macroscale Implications -

Global energy consumption will increase in the next decades and it is expected to largely rely on fossil fuels. The use of fossil fuels is intimately related to CO{sub 2} emissions and the potential for global warming. Geological CO{sub 2} storage aims to mitigate the global warming problem by sequestering CO{sub 2} underground. Coupled hydro-chemo-mechanical phenomena determine the successful operation and long term stability of CO{sub 2} geological storage. This research explores coupled phenomena, identifies different zones in the storage reservoir, and investigates their implications in CO{sub 2} geological storage. In particular, the research: Explores spatial patterns in mineral dissolution and precipitation (comprehensive mass balance formulation); experimentally determines the interfacial properties of water, mineral, and CO{sub 2} systems (including CO{sub 2}-water-surfactant mixtures to reduce the CO{sub 2}- water interfacial tension in view of enhanced sweep efficiency); analyzes the interaction between clay particles and CO{sub 2}, and the response of sediment layers to the presence of CO{sub 2} using specially designed experimental setups and complementary analyses; couples advective and diffusive mass transport of species, together with mineral dissolution to explore pore changes during advection of CO{sub 2}-dissolved water along a rock fracture; upscales results to a porous medium using pore network …
Date: May 31, 2013
Creator: Santamarina, J. Carlos
Object Type: Report
System: The UNT Digital Library
Corn Storage Protein - A Molecular Genetic Model (open access)

Corn Storage Protein - A Molecular Genetic Model

Corn is the highest yielding crop on earth and probably the most valuable agricultural product of the United States. Because it converts sun energy through photosynthesis into starch and proteins, we addressed energy savings by focusing on protein quality. People and animals require essential amino acids derived from the digestion of proteins. If proteins are relatively low in certain essential amino acids, the crop becomes nutritionally defective and has to be supplemented. Such deficiency affects meat and fish production and countries where corn is a staple. Because corn seed proteins have relatively low levels of lysine and methionine, a diet has to be supplemented with soybeans for the missing lysine and with chemically synthesized methionine. We therefore have studied genes expressed during maize seed development and their chromosomal organization. A critical technical requirement for the understanding of the molecular structure of genes and their positional information was DNA sequencing. Because of the length of sequences, DNA sequencing methods themselves were insufficient for this type of analysis. We therefore developed the so-called “DNA shotgun sequencing” strategy, where overlapping DNA fragments were sequenced in parallel and used to reconstruct large DNA molecules via overlaps. Our publications became the most frequently cited ones …
Date: May 31, 2013
Creator: Messing, Joachim
Object Type: Report
System: The UNT Digital Library
Defense Infrastructure: DOD Should Improve Reporting and Communication on Its Corrosion Prevention and Control Activities (open access)

Defense Infrastructure: DOD Should Improve Reporting and Communication on Its Corrosion Prevention and Control Activities

A letter report issued by the Government Accountability Office with an abstract that begins "The Department of Defense (DOD) has invested more than $68 million in 80 projects in fiscal years 2005 through 2010 to demonstrate new technology addressing infrastructure-related corrosion, but project managers have not submitted all required reports on the results of these efforts to the Corrosion Policy and Oversight Office (Corrosion Office). The DOD Corrosion Prevention and Mitigation Strategic Plan requires project managers to submit a final report when a project is complete, and submit a follow-on report within two years after the military department implements the technology. As of November 2012, GAO found that project managers had not submitted final reports for 50 of the 80 projects (63 percent) funded in fiscal years 2005 through 2010. Also, project managers had not submitted follow-on reports for 15 of the 41 projects (37 percent) funded in fiscal years 2005 through 2007. GAO found that the Corrosion Office’s tracking system lacks key information to help ensure that project managers meet reporting requirements. Furthermore, the Corrosion Office is not fully exercising its authority to identify and implement options or incentives to address funding and other reasons given for not meeting …
Date: May 31, 2013
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Efficient Regeneration of Physical and Chemical Solvents for CO{sub 2} Capture (open access)

Efficient Regeneration of Physical and Chemical Solvents for CO{sub 2} Capture

The objective of this project was to evaluate the use of composite polymer membranes and porous membrane contactors to regenerate physical and chemical solvents for capture of carbon dioxide (CO{sub 2}) from synthesis gas or flue gas, with the goal of improving the energy efficiency of carbon capture. Both a chemical solvent (typical for a post-combustion capture of CO{sub 2} from flue gas) and a physical solvent (typical for pre- combustion capture of CO{sub 2} from syngas) were evaluated using two bench-scale test systems constructed for this project. For chemical solvents, polytetrafluoroethylene and polypropylene membranes were found to be able to strip CO{sub 2} from a monoethanolamine (MEA) solution with high selectivity without significant degradation of the material. As expected, the regeneration temperature was the most significant parameter affecting the CO{sub 2} flux through the membrane. Pore size was also found to be important, as pores larger than 5 microns lead to excessive pore wetting. For physical solvents, polydimethyl-siloxane (PDMS)-based membranes were found to have a higher CO{sub 2} permeability than polyvinylalcohol (PVOH) based membranes, while also minimizing solvent loss. Overall, however, the recovery of CO{sub 2} in these systems is low – less than 2% for both chemical and …
Date: May 31, 2013
Creator: Tande, Brian; Seames, Wayne & Benson, Steve
Object Type: Report
System: The UNT Digital Library
Fairbanks Geothermal Energy Project Final Report (open access)

Fairbanks Geothermal Energy Project Final Report

The primary objective for the Fairbanks Geothermal Energy Project is to provide another source of base-load renewable energy in the Fairbanks North Star Borough (FNSB). To accomplish this, Chena Hot Springs Resort (Chena) drilled a re-injection well to 2700 feet and a production well to 2500 feet. The re-injection well allows a greater flow of water to directly replace the water removed from the warmest fractures in the geothermal reservoir. The new production will provide access to warmer temperature water in greater quantities.
Date: May 31, 2013
Creator: Karl, Bernie
Object Type: Report
System: The UNT Digital Library
Filibusters and Cloture in the Senate (open access)

Filibusters and Cloture in the Senate

None
Date: May 31, 2013
Creator: Beth, Richard S. & Heitshusen, Valerie
Object Type: Report
System: The UNT Digital Library
FINAL REPORT DE-FG02-07ER15894 (open access)

FINAL REPORT DE-FG02-07ER15894

One of the greatest technological hurdles to deployment of fuel cells relates to the sluggish activity, low durability and the high cost of the catalysts that are currently employed. For automotive PEM fuel cells to become commercially viable, the Pt-specific power density would need to be reduced to less than 0.2gPt/kW (at cell voltages >0.65 V). This would require the Pt loadings to be less than 0.15 mgPt/cm2MEA within the membrane electrode assembly. This could be achieved by enhancing the catalytic activity at the cathode, thus lowering its overpotential. Various different Pt-alloys have shown 2-4 times enhanced activities over Pt alone but still suffer some of the same durability issues as that of the pure Pt. There is a general loss of active Pt due to dissolution and sintering. While there have been a number of elegant fundamental experimental and theoretical studies on ideal single crystal Pt and Pt alloy surfaces which have helped to elucidate the factors that control the activity, there have been very few fundamental studies focused on the stability, reactivity and durability of well-defined Pt nanoparticles. We carried out ab initio density functional theory together with a novel double reference method that we developed to simulate …
Date: May 31, 2013
Creator: Neurock, Matthew
Object Type: Report
System: The UNT Digital Library
Improved Flow-Field Structures for Direct Methanol Fuel Cells (open access)

Improved Flow-Field Structures for Direct Methanol Fuel Cells

The direct methanol fuel cell (DMFC) is ideal if high energy-density liquid fuels are required. Liquid fuels have advantages over compressed hydrogen including higher energy density and ease of handling. Although state-of-the-art DMFCs exhibit manageable degradation rates, excessive fuel crossover diminishes system energy and power density. Although use of dilute methanol mitigates crossover, the concomitant lowering of the gross fuel energy density (GFED) demands a complex balance-of-plant (BOP) that includes higher flow rates, external exhaust recirculation, etc. An alternative approach is redesign of the fuel delivery system to accommodate concentrated methanol. NuVant Systems Inc. (NuVant) will maximize the GFED by design and assembly of a DMFC that uses near neat methanol. The approach is to tune the diffusion of highly concentrated methanol (to the anode catalytic layer) to the back-diffusion of water formed at the cathode (i.e. in situ generation of dilute methanol at the anode layer). Crossover will be minimized without compromising the GFED by innovative integration of the anode flow-field and the diffusion layer. The integrated flow-field-diffusion-layers (IFDLs) will widen the current and potential DMFC operating ranges and enable the use of cathodes optimized for hydrogen-air fuel cells.
Date: May 31, 2013
Creator: Gurau, Bogdan
Object Type: Report
System: The UNT Digital Library
Iran Sanctions. May 2013 (open access)

Iran Sanctions. May 2013

This report analyzes U.S. and international sanctions against Iran and, in so doing, provides examples, based on a wide range of open source reporting, of companies and countries that conduct business with Iran.
Date: May 31, 2013
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Measurement of the Inclusive Isolated Prompt Photon Cross-Section in $Pp$ Collisions at $\sqrt{s}=7$ TeV Using 35 Pb-1 of ATLAS Data (open access)

Measurement of the Inclusive Isolated Prompt Photon Cross-Section in $Pp$ Collisions at $\sqrt{s}=7$ TeV Using 35 Pb-1 of ATLAS Data

None
Date: May 31, 2013
Creator: Aad, Georges
Object Type: Article
System: The UNT Digital Library
Meausrement of the Neutron Radius of {sup 208}Pb Through Parity Violation in Electron Scattering (open access)

Meausrement of the Neutron Radius of {sup 208}Pb Through Parity Violation in Electron Scattering

In contrast to the nuclear charge densities, which have been accurately measured with electron scattering, the knowledge of neutron densities still lack precision. Previous model-dependent hadron experiments suggest the difference between the neutron radius, R{sub n}, of a heavy nucleus and the proton radius, R{sub p}, to be in the order of several percent. To accurately obtain the difference, R{sub n}-R{sub p}, which is essentially a neutron skin, the Jefferson Lab Lead ({sup 208}Pb) Radius Experiment (PREX) measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from {sup 208}Pb at an energy of 1.06 GeV and a scattering angle of 5{degrees}#14;. Since Z{sup 0} boson couples mainly to neutrons, this asymmetry provides a clean measurement of R{sub n} with respect to R{sub p}. PREX was conducted at the Jefferson lab experimental Hall A, from March to June 2010. The experiment collected a final data sample of 2x#2;10{sup 7} helicity-window quadruplets. The measured parity-violating electroweak asymmetry A{sub PV} = 0.656 {+-}#6; 0.060 (stat) {+-}#6; 0.014 (syst) ppm corresponds to a difference between the radii of the neutron and proton distributions, R{sub n}-R{sub p} = 0.33{sup +0.16}{sub -0.18} fm and provides the #12;first electroweak observation of the neutron skin …
Date: May 31, 2013
Creator: Saenboonruang, Kiadtisak
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Medicare Imaging Accreditation: Establishing Minimum National Standards and an Oversight Framework Would Help Ensure Quality and Safety of Advanced Diagnostic Imaging Services (open access)

Medicare Imaging Accreditation: Establishing Minimum National Standards and an Oversight Framework Would Help Ensure Quality and Safety of Advanced Diagnostic Imaging Services

A letter report issued by the Government Accountability Office with an abstract that begins "The Centers for Medicare & Medicaid Services (CMS) did not establish minimum national standards for the accreditation of suppliers of advanced diagnostic imaging (ADI) services, which cover the production of images for computed tomography, magnetic resonance imaging, and nuclear medicine services. While CMS adopted the broad criteria from the Medicare Improvements for Patients and Providers Act of 2008 (MIPPA) for ADI accreditation, it relied on the three accrediting organizations it selected to establish their own standards for quality and safety. To establish a framework for assessing the ADI standards currently in use, GAO developed a list of nine standards based on recommendations from 11 organizations with imaging expertise from which GAO obtained information. Two of the three accrediting organizations that CMS selected use all nine standards, while the third organization uses six of the nine standards. For example, while two of the organizations evaluate suppliers' patient images, the third said that it instead assesses suppliers' compliance with other standards necessary to maintain image quality, such as those related to inspection and testing of imaging equipment. As a result of these significant differences among the accrediting organizations, …
Date: May 31, 2013
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Military Parents and Child Custody: State and Federal Issues (open access)

Military Parents and Child Custody: State and Federal Issues

None
Date: May 31, 2013
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Model-Based Subspace Detectors Constructed with SPECFEM3D (open access)

Model-Based Subspace Detectors Constructed with SPECFEM3D

None
Date: May 31, 2013
Creator: Harris, D. B. & Rodgers, A. J.
Object Type: Article
System: The UNT Digital Library
Numerical Modeling of Geomechanical Processes Related to CO{sub 2} Injection within Generic Reservoirs (open access)

Numerical Modeling of Geomechanical Processes Related to CO{sub 2} Injection within Generic Reservoirs

In this project generic anticline structures have been used for numerical modeling analyses to study the influence of geometrical parameters, fluid flow boundary conditions, in situ stress regime and inter-bedding friction coefficient on geomechanical risks such as fracture reactivation and fracture generation. The resulting stress states for these structures are also used to determine safe drilling directions and a methodology for wellbore trajection optimization is developed that is applicable for non-Andersonian stress states. The results of the fluid flow simulation show that the type of fluid flow boundary condition is of utmost importance and has significant impact on all injection related parameters. It is recommended that further research is conducted to establish a method to quantify the fluid flow boundary conditions for injection applications. The results of the geomechanical simulation show that in situ stress regime is a crucial, if not the most important, factor determining geomechanical risks. For extension and strike slip stress regimes anticline structures should be favored over horizontally layered basin as they feature higher ΔP{sub c} magnitudes. If sedimentary basins are tectonically relaxed and their state of stress is characterized by the uni-axial strain model the basin is in exact frictional equilibrium and fluids should not …
Date: May 31, 2013
Creator: Eckert, Andreas
Object Type: Report
System: The UNT Digital Library
Patient Protection and Affordable Care Act: HHS's Process for Awarding and Overseeing Exchange and Rate Review Grants to States (open access)

Patient Protection and Affordable Care Act: HHS's Process for Awarding and Overseeing Exchange and Rate Review Grants to States

A letter report issued by the Government Accountability Office with an abstract that begins "The Department of Health and Human Services (HHS) has a structured process for awarding Patient Protection and Affordable Care Act (PPACA) exchange and rate review grants to states. These grants are designed to help states establish exchanges--new health insurance marketplaces through which individuals and small businesses can obtain insurance--and review issuers' proposed rate increases. The grant award process consists of a series of steps during which the agency solicits, screens, and evaluates grant applications, and then makes funding awards. Once HHS deems that applications meet program eligibility criteria, applications go through various reviews, including a review by independent experts and HHS officials. On the basis of these reviews, HHS determines whether states' proposed activities are allowable, and if so, whether the associated requests for grant funding are reasonable. Based on recommendations from the reviews, HHS determines whether to award grants to states, and if so, the amounts of any grants to be awarded."
Date: May 31, 2013
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Recovery Act: Multi-Objective Optimization Approaches for the Design of Carbon Geological Sequestration Systems (open access)

Recovery Act: Multi-Objective Optimization Approaches for the Design of Carbon Geological Sequestration Systems

The main objective of this project is to provide training opportunities for two graduate students in order to improve the human capital and skills required for implementing and deploying carbon capture and sequestration (CCS) technologies. The graduate student effort will be geared towards the formulation and implementation of an integrated simulation-optimization framework to provide a rigorous scientific support to the design CCS systems that, for any given site: (a) maximize the amount of carbon storage; (b) minimize the total cost associated with the CCS project; (c) minimize the risk of CO2 upward leakage from injected formations. The framework will stem from a combination of data obtained from geophysical investigations, a multiphase flow model, and a stochastic multi-objective optimization algorithm. The methodology will rely on a geostatistical approach to generate ensembles of scenarios of the parameters that are expected to have large sensitivities and uncertainties on the model response and thus on the risk assessment, in particular the permeability properties of the injected formation and its cap rock. The safety theme will be addressed quantitatively by including the risk of CO2 upward leakage from the injected formations as one the objectives that should be minimized in the optimization problem. The research …
Date: May 31, 2013
Creator: Bau, Domenico
Object Type: Report
System: The UNT Digital Library
Review of Exotic Hadrons (open access)

Review of Exotic Hadrons

None
Date: May 31, 2013
Creator: Renga, Francesco
Object Type: Article
System: The UNT Digital Library