Structure and Electronic Properties of Cerium Orthophosphate: Theory and Experiment (open access)

Structure and Electronic Properties of Cerium Orthophosphate: Theory and Experiment

Structural and electronic properties of cerium orthophosphate (CePO{sub 4}) are calculated using density functional theory (DFT) with the local spin-density approximation (LSDA+U), with and without gradient corrections (GGA-(PBE)+U), and compared to X-ray diffraction and photoemission spectroscopy measurements. The density of states is found to change significantly as the Hubbard parameter U, which is applied to the Ce 4f states, is varied from 0 to 5 eV. The calculated structural properties are in good agreement with experiment and do not change significantly with U. Choosing U = 3 eV for LDSA provides the best agreement between the calculated density of states and the experimental photoemission spectra.
Date: July 27, 2010
Creator: Adelstein, Nicole; Mun, B. Simon; Ray, Hannah; Ross Jr, Phillip; Neaton, Jeffrey & De Jonghe, Lutgard
Object Type: Article
System: The UNT Digital Library
The German Economy and U.S.-German Economic Relations (open access)

The German Economy and U.S.-German Economic Relations

This report discusses Germany's recent trends in economic performance and trade relations with the U.S. This report elaborates on these themes in three parts: historical economic performance; reform challenges facing German political leaders; and selected U.S.-German economic policy differences.
Date: January 27, 2010
Creator: Ahearn, Raymond J. & Belkin, Paul
Object Type: Report
System: The UNT Digital Library
Galaxy Clusters in the Swift/Bat Era Ii: 10 More Clusters Detected Above 15 Kev (open access)

Galaxy Clusters in the Swift/Bat Era Ii: 10 More Clusters Detected Above 15 Kev

We report on the discovery of 10 additional galaxy clusters detected in the ongoing Swift/BAT all-sky survey. Among the newly BAT-discovered clusters there are: Bullet, Abell 85, Norma, and PKS 0745-19. Norma is the only cluster, among those presented here, which is resolved by BAT. For all the clusters we perform a detailed spectral analysis using XMM-Newton and Swift/BAT data to investigate the presence of a hard (non-thermal) X-ray excess. We find that in most cases the clusters emission in the 0.3-200 keV band can be explained by a multi-temperature thermal model confirming our previous results. For two clusters (Bullet and Abell 3667) we find evidence for the presence of a hard X-ray excess. In the case of the Bullet cluster, our analysis confirms the presence of a non-thermal, power-law like, component with a 20-100 keV flux of 3.4 x 10{sup -12} erg cm{sup -2} s{sup -1} as detected in previous studies. For Abell 3667 the excess emission can be successfully modeled as a hot component (kT = {approx}13 keV). We thus conclude that the hard X-ray emission from galaxy clusters (except the Bullet) has most likely thermal origin.
Date: October 27, 2010
Creator: Ajello, M.; Rebusco, P.; Cappelluti, N.; Reimer, O.; Boehringer, H.; La Parola, V. et al.
Object Type: Article
System: The UNT Digital Library
A Survey of Wireless Communications for the Electric Power System (open access)

A Survey of Wireless Communications for the Electric Power System

A key mission of the U.S. Department of Energy (DOE) Office of Electricity Delivery and Energy Reliability (OE) is to enhance the security and reliability of the nation’s energy infrastructure. Improving the security of control systems, which enable the automated control of our energy production and distribution, is critical for protecting the energy infrastructure and the integral function that it serves in our lives. The DOE-OE Control Systems Security Program provides research and development to help the energy industry actively pursue advanced security solutions for control systems. The focus of this report is analyzing how, where, and what type of wireless communications are suitable for deployment in the electric power system and to inform implementers of their options in wireless technologies. The discussions in this report are applicable to enhancing both the communications infrastructure of the current electric power system and new smart system deployments. The work described in this report includes a survey of the following wireless technologies: • IEEE 802.16 d and e (WiMAX) • IEEE 802.11 (Wi-Fi) family of a, b, g, n, and s • Wireless sensor protocols that use parts of the IEEE 802.15.4 specification: WirelessHART, International Society of Automation (ISA) 100.11a, and Zigbee • …
Date: January 27, 2010
Creator: Akyol, Bora A.; Kirkham, Harold; Clements, Samuel L. & Hadley, Mark D.
Object Type: Report
System: The UNT Digital Library
A Pilot Study of the Effectiveness of Indoor Plants for Removal of Volatile Organic Compounds in Indoor Air in a Seven-Story Office Building (open access)

A Pilot Study of the Effectiveness of Indoor Plants for Removal of Volatile Organic Compounds in Indoor Air in a Seven-Story Office Building

The Paharpur Business Centre and Software Technology Incubator Park (PBC) is a 7 story, 50,400 ft{sup 2} office building located near Nehru Place in New Delhi India. The occupancy of the building at full normal operations is about 500 people. The building management philosophy embodies innovation in energy efficiency while providing full service and a comfortable, safe, healthy environment to the occupants. Provision of excellent Indoor Air Quality (IAQ) is an expressed goal of the facility, and the management has gone to great lengths to achieve it. This is particularly challenging in New Delhi, where ambient urban pollution levels rank among the worst on the planet. The approach to provide good IAQ in the building includes a range of technical elements: air washing and filtration of ventilation intake air from rooftop air handler, the use of an enclosed rooftop greenhouse with a high density of potted plants as a bio-filtration system, dedicated secondary HVAC/air handling units on each floor with re-circulating high efficiency filtration and UVC treatment of the heat exchanger coils, additional potted plants for bio-filtration on each floor, and a final exhaust via the restrooms located at each floor. The conditioned building exhaust air is passed through an …
Date: April 27, 2010
Creator: Apte, Michael G. & Apte, Joshua S.
Object Type: Report
System: The UNT Digital Library
Observation of snake resonances at Relativistic Heavy Ion Collider (open access)

Observation of snake resonances at Relativistic Heavy Ion Collider

The Siberian snakes are powerful tools in preserving polarization in high energy accelerators has been demonstrated at the Brookhaven Relativistic Heavy Ion Collider (RHIC). Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the Siberian snakes also introduce a new set of depolarization resonances, i.e. snake resonances as first discovered by Lee and Tepikian. The intrinsic spin resonances above 100 GeV are about a factor of two stronger than those below 100 GeV which raises the challenge to preserve the polarization up to 250 GeV. In 2009, polarized protons collided for the first time at the RHIC design store energy of 250 GeV. This paper presents the experimental measurements of snake resonances at RHIC. The plan for avoiding these resonances is also presented.
Date: September 27, 2010
Creator: Bai, M.; Ahrens, L.; Alekseev, I.G.; Alessi, J. & al, et
Object Type: Article
System: The UNT Digital Library
Relativistic Heavy Ion Collider spin flipper commissioning plan (open access)

Relativistic Heavy Ion Collider spin flipper commissioning plan

The commissioning of the RHIC spin flipper in the RHIC Blue ring during the RHIC polarized proton run in 2009 showed the detrimental effects of global vertical coherent betatron oscillation induced by the 2-AC dipole plus 4-DC dipole configuration. This global orbital coherent oscillation of the RHIC beam in the Blue ring in the presence of collision modulated the beam-beam interaction between the two RHIC beams and affected Yellow beam lifetime. The experimental data at injection with different spin tunes by changing the snake current also demonstrated that it was not possible to induce a single isolated spin resonance with the global vertical coherent betatron oscillation excited by the two AC dipoles. Hence, RHIC spin flipper was re-designed to eliminate the coherent vertical betatron oscillation outside the spin flipper by adding three additional AC dipoles. This paper presents the experimental results as well as the new design.
Date: September 27, 2010
Creator: Bai, M.; Dawson, C.; Makdisi, Y.; Meng, W.; Meot, F.; Oddo, P. et al.
Object Type: Article
System: The UNT Digital Library
Defense Logistical Support Contracts in Iraq and Afghanistan: Issues for Congress (open access)

Defense Logistical Support Contracts in Iraq and Afghanistan: Issues for Congress

This report examines logistical support contracts for troop support services in Iraq and Afghanistan (for Afghanistan, beginning with LOGCAP IV) administered through the U.S. Army's Logistics Civil Augmentation Program (LOGCAP). LOGCAP is an initiative designed to manage the use of civilian contractors that perform services during times of war and other military mobilizations.
Date: January 27, 2010
Creator: Bailey Grasso, Valerie
Object Type: Report
System: The UNT Digital Library
HEP Science Network Requirements (open access)

HEP Science Network Requirements

The Energy Sciences Network (ESnet) is the primary provider of network connectivity for the US Department of Energy Office of Science, the single largest supporter of basic research in the physical sciences in the United States. In support of the Office of Science programs, ESnet regularly updates and refreshes its understanding of the networking requirements of the instruments, facilities, scientists, and science programs that it serves. This focus has helped ESnet to be a highly successful enabler of scientific discovery for over 20 years. In August 2009 ESnet and the Office of High Energy Physics (HEP), of the DOE Office of Science, organized a workshop to characterize the networking requirements of the programs funded by HEP. The International HEP community has been a leader in data intensive science from the beginning. HEP data sets have historically been the largest of all scientific data sets, and the communty of interest the most distributed. The HEP community was also the first to embrace Grid technologies. The requirements identified at the workshop are summarized below, and described in more detail in the case studies and the Findings section: (1) There will be more LHC Tier-3 sites than orginally thought, and likely more Tier-2 …
Date: April 27, 2010
Creator: Bakken, Jon; Barczyk, Artur; Blatecky, Alan; Boehnlein, Amber; Carlson, Rich; Chekanov, Sergei et al.
Object Type: Report
System: The UNT Digital Library
Higher Order Mode Heating Analysis for the ILC Superconducting Linacs (open access)

Higher Order Mode Heating Analysis for the ILC Superconducting Linacs

The superconducting cavities and interconnects in the 11 km long linacs of the International Linear Collider (ILC) are designed to operate at 2K, where cooling costs are very expensive. It is thus important to minimize cryogenic heat loads. In addition to an unavoidable static load and the dynamic load of the fundamental 1.3 GHz accelerating rf, a further heat source is presented by the higher order mode (HOM) power deposited by the beam. Such modes will be damped by specially designed HOM couplers attached to the cavities (for trapped modes), and by ceramic dampers at 70K that are located between the eight or nine cavity cryomodules (for propagating modes). Brute force calculation of the higher frequency modes excited in a string of cryomodules is limited by computing capacity (see, e.g. [1]). M. Liepe has calculated {approx} 400 longitudinal TM modes in 3 superconducting cavities plus absorbers, up to 8 GHz [2]. Joestingmeier, et al., have used a ray tracing calculation to find the effect at higher frequencies, specifically in the range of tens of GHz and above [3]. In this report we present a scattering matrix approach, which we apply to an rf unit comprising 26 cavities and 3 absorbers. …
Date: October 27, 2010
Creator: Bane, K. L. F.; Nantista, C. & Adolphsen, C.
Object Type: Article
System: The UNT Digital Library
Gap Assessment in the Emergency Response Community (open access)

Gap Assessment in the Emergency Response Community

This report describes a gap analysis of the emergency response and management (EM) community, performed during the fall of 2009. Pacific Northwest National Laboratory (PNNL) undertook this effort to identify potential improvements to the functional domains in EM that could be provided by the application of current or future technology. To perform this domain-based gap analysis, PNNL personnel interviewed subject matter experts (SMEs) across the EM domain; to make certain that the analyses reflected a representative view of the community, the SMEs were from a variety of geographic areas and from various sized communities (urban, suburban, and rural). PNNL personnel also examined recent and relevant after-action reports and U.S. Government Accountability Office reports.
Date: September 27, 2010
Creator: Barr, Jonathan L.; Burtner, Edwin R.; Pike, William A.; Peddicord, Annie M Boe & Minsk, Brian S.
Object Type: Report
System: The UNT Digital Library
Federal Stafford Act Disaster Assistance: Presidential Declarations, Eligible Activities, and Funding (open access)

Federal Stafford Act Disaster Assistance: Presidential Declarations, Eligible Activities, and Funding

This report discusses the Robert T. Stafford Disaster Relief and Emergency Assistance Act (the Stafford Act) that authorizes the President to issue major disaster, emergency, and fire management declarations, which in turn enable federal agencies to provide assistance to state and local governments overwhelmed by catastrophes.
Date: January 27, 2010
Creator: Bea, Keith
Object Type: Report
System: The UNT Digital Library
FY2010 Supplemental for Wars, Disaster Assistance, Haiti Relief, and Other Programs (open access)

FY2010 Supplemental for Wars, Disaster Assistance, Haiti Relief, and Other Programs

This report provides an overview of FY2010 supplemental appropriations and discusses this year's supplemental focused on the effect on the deficit of additional spending.
Date: July 27, 2010
Creator: Belasco, Amy; Else, Daniel H.; Lindsay, Bruce R.; Margesson, Rhoda; Nakamura, Kennon H.; Taft-Morales, Maureen et al.
Object Type: Report
System: The UNT Digital Library

Thermal Management of Power Semiconductor Packages - Matching Cooling Technologies with Packaging Technologies

Heat removal for power semiconductor devices is critical for robust operation. Because there are different packaging options, different thermal management technologies, and a range of applications, there is a need for a methodology to match cooling technologies and package configurations to target applications. To meet this need, a methodology was developed to compare the sensitivity of cooling technologies on the overall package thermal performance over a range of power semiconductor packaging configurations. The results provide insight into the trade-offs associated with cooling technologies and package configurations. The approach provides a method for comparing new developments in power semiconductor packages and identifying potential thermal control technologies for the package. The results can help users select the appropriate combination of packaging configuration and cooling technology for the desired application.
Date: April 27, 2010
Creator: Bennion, K. & Moreno, G.
Object Type: Presentation
System: The UNT Digital Library
Intelligence Authorization Legislation: Status and Challenges (open access)

Intelligence Authorization Legislation: Status and Challenges

This report assesses the effects of the absence of intelligence authorization legislation since FY2005. Since FY2005, no annual intelligence authorization bill has been enacted. Although the National Security Act requires intelligence activities to be specifically authorized, this requirement has been satisfied in recent years by one-sentence catch-all provisions in defense appropriations acts authorizing intelligence activities.
Date: January 27, 2010
Creator: Best, Richard A., Jr.
Object Type: Report
System: The UNT Digital Library
Science and Technology Review July/August 2010 (open access)

Science and Technology Review July/August 2010

This issue has the following articles: (1) Deterrence with a Minimum Nuclear Stockpile - Commentary by Bruce T. Goodwin; (2) Enhancing Confidence in the Nation's Nuclear Stockpile - Livermore experts are participating in a national effort aimed at predicting how nuclear weapon materials and systems will likely change over time; (3) Narrowing Uncertainties - For climate modeling and many other fields, understanding uncertainty, or margin of error, is critical; (4) Insight into a Deadly Disease - Laboratory experiments reveal the pathogenesis of tularemia in host cells, bringing scientists closer to developing a vaccine for this debilitating disease. (5) Return to Rongelap - On the Rongelap Atoll, Livermore scientists are working to minimize radiological exposure for natives now living on or wishing to return to the islands.
Date: May 27, 2010
Creator: Blobaum, K M
Object Type: Report
System: The UNT Digital Library
Shutdown of the Federal Government: Causes, Processes, and Effects (open access)

Shutdown of the Federal Government: Causes, Processes, and Effects

This report discusses the causes of funding gaps and shutdowns of the federal government, processes that are associated with shutdowns, and how agency operations may be affected by shutdowns. The report concludes with a discussion of potential issues for Congress.
Date: September 27, 2010
Creator: Brass, Clinton T.
Object Type: Report
System: The UNT Digital Library
THE OXYGEN PERMEATION PROPERTIES OF NANO CRYSTALLINE CEO2 THIN FILMS (open access)

THE OXYGEN PERMEATION PROPERTIES OF NANO CRYSTALLINE CEO2 THIN FILMS

The measurement of oxygen flux across nanocrystalline CeO{sub 2} cerium oxide thin films at intermediate temperature (650 to 800 C) is presented. Porous ceria support substrates were fabricated by sintering with carbon additions. The final dense film was deposited from an optimized sol-gel solution resulting in a mean grain size of 50 nm which displayed oxygen flux values of up to 0.014 {micro}mol/cm{sup 2}s over the oxygen partial pressure range from air to helium gas used in the measurement at 800 C. The oxygen flux characteristics confirm mixed ionic and electronic conductivity in nanocrystalline ceria films and demonstrate the role of size dependent materials properties as a design parameter in functional membranes for oxygen separation.
Date: September 27, 2010
Creator: Brinkman, K.
Object Type: Article
System: The UNT Digital Library
QCD and Light-Front Holography (open access)

QCD and Light-Front Holography

The soft-wall AdS/QCD model, modified by a positive-sign dilaton metric, leads to a remarkable one-parameter description of nonperturbative hadron dynamics. The model predicts a zero-mass pion for zero-mass quarks and a Regge spectrum of linear trajectories with the same slope in the leading orbital angular momentum L of hadrons and the radial quantum number N. Light-Front Holography maps the amplitudes which are functions of the fifth dimension variable z of anti-de Sitter space to a corresponding hadron theory quantized on the light front. The resulting Lorentz-invariant relativistic light-front wave equations are functions of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. The result is to a semi-classical frame-independent first approximation to the spectra and light-front wavefunctions of meson and baryon light-quark bound states, which in turn predict the behavior of the pion and nucleon form factors. The theory implements chiral symmetry in a novel way: the effects of chiral symmetry breaking increase as one goes toward large interquark separation, consistent with spectroscopic data, and the the hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has …
Date: October 27, 2010
Creator: Brodsky, Stanley J. & de Teramond, Guy F.
Object Type: Article
System: The UNT Digital Library
The $\hbar$ Expansion in Quantum Field Theory (open access)

The $\hbar$ Expansion in Quantum Field Theory

We show how expansions in powers of Planck's constant {h_bar} = h = 2{pi} can give new insights into perturbative and nonperturbative properties of quantum field theories. Since {h_bar} is a fundamental parameter, exact Lorentz invariance and gauge invariance are maintained at each order of the expansion. The physics of the {h_bar} expansion depends on the scheme; i.e., different expansions are obtained depending on which quantities (momenta, couplings and masses) are assumed to be independent of {h_bar}. We show that if the coupling and mass parameters appearing in the Lagrangian density are taken to be independent of {h_bar}, then each loop in perturbation theory brings a factor of {h_bar}. In the case of quantum electrodynamics, this scheme implies that the classical charge e, as well as the fine structure constant are linear in {h_bar}. The connection between the number of loops and factors of {h_bar} is more subtle for bound states since the binding energies and bound-state momenta themselves scale with {h_bar}. The {h_bar} expansion allows one to identify equal-time relativistic bound states in QED and QCD which are of lowest order in {h_bar} and transform dynamically under Lorentz boosts. The possibility to use retarded propagators at the Born level …
Date: October 27, 2010
Creator: Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Hoyer, Paul & /Southern Denmark U., CP3-Origins /Helsinki U. /Helsinki Inst. of Phys.
Object Type: Article
System: The UNT Digital Library
Unauthorized Alien Students: Issues and "DREAM Act" Legislation (open access)

Unauthorized Alien Students: Issues and "DREAM Act" Legislation

Supporters of comprehensive immigration reform have urged the President and Congress to pursue reform legislation. While legislative action on comprehensive reform does not appear likely during the remainder of the 111th Congress, there may be an effort to enact a measure, commonly referred to as the "DREAM Act," to enable certain unauthorized alien students to legalize their status. This report discusses the DREAM act and related issues.
Date: October 27, 2010
Creator: Bruno, Andorra
Object Type: Report
System: The UNT Digital Library
Unauthorized Aliens in the United States (open access)

Unauthorized Aliens in the United States

This report discusses the unauthorized immigrant (illegal alien) population in the United States, which is a key and controversial immigration issue.
Date: April 27, 2010
Creator: Bruno, Andorra
Object Type: Report
System: The UNT Digital Library
Creep and Creep-Fatigue Crack Growth at Structural Discontinuities and Welds (open access)

Creep and Creep-Fatigue Crack Growth at Structural Discontinuities and Welds

The subsection ASME NH high temperature design procedure does not admit crack-like defects into the structural components. The US NRC identified the lack of treatment of crack growth within NH as a limitation of the code and thus this effort was undertaken. This effort is broken into two parts. Part 1, summarized here, involved examining all high temperature creep-fatigue crack growth codes being used today and from these, the task objective was to choose a methodology that is appropriate for possible implementation within NH. The second part of this task, which has just started, is to develop design rules for possible implementation within NH. This second part is a challenge since all codes require step-by-step analysis procedures to be undertaken in order to assess the crack growth and life of the component. Simple rules for design do not exist in any code at present. The codes examined in this effort included R5, RCC-MR (A16), BS 7910, API 579, and ATK (and some lesser known codes). There are several reasons that the capability for assessing cracks in high temperature nuclear components is desirable. These include: (1) Some components that are part of GEN IV reactors may have geometries that have sharp …
Date: January 27, 2010
Creator: Brust, F. W.; Wilkowski, G. M.; Krishnaswamy, P. & Wichman, Keith
Object Type: Report
System: The UNT Digital Library
Ocean Acidification (open access)

Ocean Acidification

This report discusses the increasing concern, within the scientific community, that rising levels of carbon dioxide in the atmosphere could detrimentally alter marine ecosystems. The report discusses how ocean acidification happens, its possible outcomes, as well as natural and human responses that could possibly limit or reduce the rate of the process.
Date: May 27, 2010
Creator: Buck, Eugene H. & Folger, Peter
Object Type: Report
System: The UNT Digital Library