States

Where the Sidewalk Ends: Jets and Missing Energy Search Strategies for the 7 TeV LHC (open access)

Where the Sidewalk Ends: Jets and Missing Energy Search Strategies for the 7 TeV LHC

This work explores the potential reach of the 7 TeV LHC to new colored states in the context of simplified models and addresses the issue of which search regions are necessary to cover an extensive set of event topologies and kinematic regimes. This article demonstrates that if searches are designed to focus on specific regions of phase space, then new physics may be missed if it lies in unexpected corners. Simple multiregion search strategies can be designed to cover all of kinematic possibilities. A set of benchmark models are created that cover the qualitatively different signatures and a benchmark multiregion search strategy is presented that covers these models.
Date: August 15, 2011
Creator: Alves, Daniele S.M.; Izaguirre, Eder; Wacker, Jay G. & /SLAC /Stanford U., ITP
Object Type: Article
System: The UNT Digital Library
Federal Agency Authority to Contract for Electric Power and Renewable Energy Supply (open access)

Federal Agency Authority to Contract for Electric Power and Renewable Energy Supply

None
Date: August 15, 2011
Creator: Andrews, Anthony
Object Type: Report
System: The UNT Digital Library
Energy Saving Melting and Revert Reduction Technology: Innovative Semi-Solid Metal (SSM) Processing (open access)

Energy Saving Melting and Revert Reduction Technology: Innovative Semi-Solid Metal (SSM) Processing

Semi-solid metal (SSM) processing has emerged as an attractive method for near-net-shape manufacturing due to the distinct advantages it holds over conventional near-net-shape forming technologies. These advantages include lower cycle time, increased die life, reduced porosity, reduced solidification shrinkage, improved mechanical properties, etc. SSM processing techniques can not only produce the complex dimensional details (e.g. thin-walled sections) associated with conventional high-pressure die castings, but also can produce high integrity castings currently attainable only with squeeze and low-pressure permanent mold casting processes. There are two primary semi-solid processing routes, (a) thixocasting and (b) rheocasting. In the thixocasting route, one starts from a non-dendritic solid precursor material that is specially prepared by a primary aluminum manufacturer, using continuous casting methods. Upon reheating this material into the mushy (a.k.a. "two-phase") zone, a thixotropic slurry is formed, which becomes the feed for the casting operation. In the rheocasting route (a.k.a. "slurry-on-demand" or "SoD"), one starts from the liquid state, and the thixotropic slurry is formed directly from the melt via careful thermal management of the system; the slurry is subsequently fed into the die cavity. Of these two routes, rheocasting is favored in that there is no premium added to the billet cost, and …
Date: August 15, 2012
Creator: Apelian, Diran
Object Type: Report
System: The UNT Digital Library
Improving the Top Quark Forward-Backward Asymmetry Measurement at the LHC (open access)

Improving the Top Quark Forward-Backward Asymmetry Measurement at the LHC

At the LHC, top quark pairs are dominantly produced from gluons, making it difficult to measure the top quark forward-backward asymmetry. To improve the asymmetry measurement, we study variables that can distinguish between top quarks produced from quarks and those from gluons: the invariant mass of the top pair, the rapidity of the top-antitop system in the lab frame, the rapidity of the top quark in the top-antitop rest frame, the top quark polarization and the top-antitop spin correlation. We combine all the variables in a likelihood discriminant method to separate quark-initiated events from gluon-initiated events. We apply our method on models including G-prime's and W-prime's motivated by the recent observation of a large top quark forward-backward asymmetry at the Tevatron. We have found that the significance of the asymmetry measurement can be improved by 10% to 30%. At the same time, the central values of the asymmetry increase by 40% to 100%. We have also analytically derived the best spin quantization axes for studying top quark polarization as well as spin-correlation for the new physics models.
Date: August 15, 2011
Creator: Bai, Yang & Han, Zhenyu
Object Type: Article
System: The UNT Digital Library
A Piecewise Linear Discontinuous Finite Element Spatial Discretization of the Sn Transport Equation for Polyhedral Grids in 3D Cartesian Geometry (open access)

A Piecewise Linear Discontinuous Finite Element Spatial Discretization of the Sn Transport Equation for Polyhedral Grids in 3D Cartesian Geometry

None
Date: August 15, 2011
Creator: Bailey, T S; Hawkins, W D & Adams, M L
Object Type: Article
System: The UNT Digital Library
Final Report (open access)

Final Report

The year 2008 resulted in 99 scans that were funded through NIH agencies. An additional 43 MRI scans were funded by industry. Over 250 scans were acquired by various investigators as �pilot� data to be used for future grant applications. While these numbers are modest in comparison to most busy research MRI Centers, they are in line with that of a newly established MRI research facility. The initial 12-18 months of operation were primarily dedicated to establishing new IRB approved research studies, and acquiring pilot data for future grant applications. During the year 2009 the MRI Center continued to show positive growth with respect to funded studies and the number of scan sessions. The number of NIH sponsored scans increased to 242 and the number of industry funded studies climbed to 81. This more than doubled our numbers of funded scans over the previous year. In addition, 398 scans were acquired as pilot data; most of which were fMRI�s. The MRI Center continued to expand with additional researchers who were interested in probing the brain�s response to chronic pain. Other studies looked at regions of brain activation in patients with impulsivity disorders; including smokers. A large majority of the imaging …
Date: August 15, 2013
Creator: Bernstein, Ira Mark
Object Type: Text
System: The UNT Digital Library
Domestic Terrorism Appears to Be Reemerging as a Priority at the Department of Justice (open access)

Domestic Terrorism Appears to Be Reemerging as a Priority at the Department of Justice

This document examines an apparent shift in priorities at the Department of Justice (DOJ) towards a renewed focus on domestic terrorism with the reestablishment of its Domestic Terrorism Executive Committee, which had been defunct for several years. The report considers why the shift in focus may be occurring and also briefly examines different types of domestic terror threats.
Date: August 15, 2014
Creator: Bjelopera, Jerome P.
Object Type: Report
System: The UNT Digital Library
Instream Flows Research and Validation Methodology Framework 2016-2017: Colorado and Lavaca Rivers (open access)

Instream Flows Research and Validation Methodology Framework 2016-2017: Colorado and Lavaca Rivers

Report on understanding flow-ecology responses and addressing questions and concerns raised during the SB 3 process, including recommendations for continued evaluations, additional surveys, and the establishment of direct ecological responses.
Date: August 15, 2017
Creator: Bonner, Timothy H. (Timothy Hallman), 1969- & Duke, Jacquelyn R.
Object Type: Report
System: The Portal to Texas History
Instream Flows Research and Validation Methodology Framework 2016-2017 (open access)

Instream Flows Research and Validation Methodology Framework 2016-2017

Report on environmental flow for the Brazos area on accurately depicting flow standards for the Brazos and other basins.
Date: August 15, 2017
Creator: Bonner, Timothy; Duke, Jacquelyn & Guillen, George
Object Type: Report
System: The Portal to Texas History
Improving the phase stability and oxidation resistance of B-NiAl (open access)

Improving the phase stability and oxidation resistance of B-NiAl

High temperature alloys are essential to many industries that require a stable material to perform in harsh oxidative environments. Many of these alloys are suited for specific applications such as jet engine turbine blades where most other materials would either melt or oxidize and crumble (1). These alloys must have a high melting temperature, excellent oxidation resistance, good creep resistance, and decent fracture toughness to be successfully used in such environments. The discovery of Ni based superalloys in the 1940s revolutionized the high temperature alloy industry and there has been continued development of these alloys since their advent (2). These materials are capable of operating in oxidative environments in the presence of combustion gases, water vapor and at temperatures around 1050 C. Demands for increased f uel efficiency, however, has highlighted the need for materials that can be used under similar atmospheres and at temperatures in excess of 1200 C. The current Ni based superalloys are restricted to lower temperatures due to the presence of a number of low melting phases that result in softening of the alloys above 1000 C. Therefore, recent research has been aimed at exploring and developing newer alloy systems that can meet the escalating requirements. …
Date: August 15, 2011
Creator: Brammer, Travis
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Light-Front Holography and the Light-Front Schrodinger Equation (open access)

Light-Front Holography and the Light-Front Schrodinger Equation

One of the most important nonperturbative methods for solving QCD is quantization at fixed light-front time {tau} = t+z=c - Dirac's 'Front Form'. The eigenvalues of the light-front QCD Hamiltonian predict the hadron spectrum and the eigensolutions provide the light-front wavefunctions which describe hadron structure. More generally, we show that the valence Fock-state wavefunctions of the light-front QCD Hamiltonian satisfy a single-variable relativistic equation of motion, analogous to the nonrelativistic radial Schrodinger equation, with an effective confining potential U which systematically incorporates the effects of higher quark and gluon Fock states. We outline a method for computing the required potential from first principles in QCD. The holographic mapping of gravity in AdS space to QCD, quantized at fixed light-front time, yields the same light front Schrodinger equation; in fact, the soft-wall AdS/QCD approach provides a model for the light-front potential which is color-confining and reproduces well the light-hadron spectrum. One also derives via light-front holography a precise relation between the bound-state amplitudes in the fifth dimension of AdS space and the boost-invariant light-front wavefunctions describing the internal structure of hadrons in physical space-time. The elastic and transition form factors of the pion and the nucleons are found to be well …
Date: August 15, 2012
Creator: Brodsky, Stanley J. & de Teramond, Guy
Object Type: Article
System: The UNT Digital Library
AIP Conference Proceedings for the 19th Topical Conference on Radio Frequency Power in Plasmas (open access)

AIP Conference Proceedings for the 19th Topical Conference on Radio Frequency Power in Plasmas

An analytic model for single particle motion in the presence of a wave field and multiple cyclotron harmonics is developed and investigated. The model suggests that even in the absence of Doppler broadening, cyclotron harmonic layers have finite spatial extent. This allows for particles to interact with more than one harmonic layer simultaneously, provided the layers are tightly packed. The latter phenomenon is investigated in the context of the model using symplectic mapping techniques. Then the model behavior is compared with numerical simulations of neutral beam particle trajectories in NSTX using the full-orbit code SPIRAL
Date: August 15, 2012
Creator: Burby, J. W.; Kramer, G. J.; Phillips, C. K. & Valeo, E. J.
Object Type: Article
System: The UNT Digital Library
Desalination: Technologies, Use, and Congressional Issues (open access)

Desalination: Technologies, Use, and Congressional Issues

This report discusses Desalination processes that generally treat seawater or brackish water to produce a stream of freshwater, and a separate, saltier stream of water that has to be disposed.
Date: August 15, 2011
Creator: Carter, Nicole T.
Object Type: Report
System: The UNT Digital Library
Theory of Two-Magnon Raman Scattering in Iron Pnictides and Chalcogenides (open access)

Theory of Two-Magnon Raman Scattering in Iron Pnictides and Chalcogenides

Although the parent iron-based pnictides and chalcogenides are itinerant antiferromagnets, the use of local moment picture to understand their magnetic properties is still widespread. We study magnetic Raman scattering from a local moment perspective for various quantum spin models proposed for this new class of superconductors. These models vary greatly in the level of magnetic frustration and show a vastly different two-magnon Raman response. Light scattering by two-magnon excitations thus provides a robust and independent measure of the underlying spin interactions. In accord with other recent experiments, our results indicate that the amount of magnetic frustration in these systems may be small.
Date: August 15, 2011
Creator: Chen, C. C.
Object Type: Article
System: The UNT Digital Library
Phase-field investigation on the non-equilibrium interface dynamics of rapid alloy solidification (open access)

Phase-field investigation on the non-equilibrium interface dynamics of rapid alloy solidification

The research program reported here is focused on critical issues that represent conspicuous gaps in current understanding of rapid solidification, limiting our ability to predict and control microstructural evolution (i.e. morphological dynamics and microsegregation) at high undercooling, where conditions depart significantly from local equilibrium. More specifically, through careful application of phase-field modeling, using appropriate thin-interface and anti-trapping corrections and addressing important details such as transient effects and a velocity-dependent (i.e. adaptive) numerics, the current analysis provides a reasonable simulation-based picture of non-equilibrium solute partitioning and the corresponding oscillatory dynamics associated with single-phase rapid solidification and show that this method is a suitable means for a self-consistent simulation of transient behavior and operating point selection under rapid growth conditions. Moving beyond the limitations of conventional theoretical/analytical treatments of non-equilibrium solute partitioning, these results serve to substantiate recent experimental findings and analytical treatments for single-phase rapid solidification. The departure from the equilibrium solid concentration at the solid-liquid interface was often observed during rapid solidification, and the energetic associated non-equilibrium solute partitioning has been treated in detail, providing possible ranges of interface concentrations for a given growth condition. Use of these treatments for analytical description of specific single-phase dendritic and cellular operating point …
Date: August 15, 2011
Creator: Choi, Jeong
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Higgs Properties in the Fourth Generation MSSM: Boosted Signals Over the 3G Plan (open access)

Higgs Properties in the Fourth Generation MSSM: Boosted Signals Over the 3G Plan

The generalization of the MSSM to the case of four chiral fermion generations (4GMSSM) can lead to significant changes in the phenomenology of the otherwise familiar Higgs sector. In most of the 3GMSSM parameter space, the lighter CP-even h is {approx} 115-125 GeV and mostly Standard Model-like while H,A,H{sup {+-}} are all relatively heavy. Furthermore, the ratio of Higgs vevs, tan {beta}, is relatively unconstrained. In contrast to this, in the 4GMSSM, heavy fourth generation fermion loops drive the masses of h,H,H{sup {+-}} to large values while the CP-odd boson, A, can remain relatively light and tan {beta} is restricted to the range 1/2 {approx}< tan {beta} {approx}< 2 due to perturbativity requirements on Yukawa couplings. We explore this scenario in some detail, concentrating on the collider signatures of the light CP-odd Higgs at both the Tevatron and LHC. We find that while gg {yields} A may lead to a potential signal in the {tau}{sup +}{tau}{sup -} channel at the LHC, A may first be observed in the {gamma}{gamma} channel due to a highly loop-enhanced cross section that can be more than an order of magnitude greater than that of a SM Higgs for A masses of {approx} 115-120 and …
Date: August 15, 2011
Creator: Cotta, R. C.; Hewett, J. L.; Ismail, A.; Le, M. -P. & Rizzo, T. G.
Object Type: Article
System: The UNT Digital Library
Horse Slaughter Prevention Bills and Issues (open access)

Horse Slaughter Prevention Bills and Issues

This report provides evidence of a rise in state and local investigations for horse neglect and more abandoned horses since 2007.
Date: August 15, 2012
Creator: Cowan, Tadlock
Object Type: Report
System: The UNT Digital Library
New Dualities in Supersymmetric Chiral Gauge Theories (open access)

New Dualities in Supersymmetric Chiral Gauge Theories

We analyze the phase structure of supersymmetric chiral gauge theories with gauge group SU(N), an antisymmetric, and F {le} N + 3 flavors, in the presence of a cubic superpotential. When F = N + 3 the theory flows to a superconformal fixed point in the infrared, and new dual descriptions of this theory are uncovered. The theory with odd N admits a self-dual magnetic description. For general N, we find an infinite family of magnetic dual descriptions, characterized by arbitrarily large gauge groups and additional classical global symmetries that are truncated by nonperturbative effects. The infrared dynamics of these theories are analyzed using a-maximization, which supports the claim that all these theories flow to the same superconformal fixed point. A very rich phase structure is found when the number of flavors is reduced below N + 3, including a new self-dual point, transitions from conformal to confining, and a nonperturbative instability for F {le} N. We also give examples of chiral theories with antisymmetrics that have nonchiral duals.
Date: August 15, 2011
Creator: Craig, Nathaniel; /Princeton, Inst. Advanced Study /Rutgers U., Piscataway; Essig, Rouven; Hook, Anson; Torroba, Gonzalo & /Stanford U., Phys. Dept. /SLAC
Object Type: Article
System: The UNT Digital Library
THERMAL PERFORMANCE SENSITIVITY STUDIES IN SUPPORT OF MATERIAL MODELING FOR EXTENDED STORAGE OF USED NUCLEAR FUEL (open access)

THERMAL PERFORMANCE SENSITIVITY STUDIES IN SUPPORT OF MATERIAL MODELING FOR EXTENDED STORAGE OF USED NUCLEAR FUEL

The work reported here is an investigation of the sensitivity of component temperatures of a storage system, including fuel cladding temperatures, in response to age-related changes that could degrade the design-basis thermal behavior of the system. Three specific areas of interest were identified for this study. • degradation of the canister backfill gas from pure helium to a mixture of air and helium, resulting from postulated leakage due to stress corrosion cracking (SCC) of canister welds • changes in surface emissivity of system components, resulting from corrosion or other aging mechanisms, which could cause potentially significant changes in temperatures and temperature distributions, due to the effect on thermal radiation exchange between components • changes in fuel and basket temperatures due to changes in fuel assembly position within the basket cells in the canister The purpose of these sensitivity studies is to provide a realistic example of how changes in the physical properties or configuration of the storage system components can affect temperatures and temperature distributions. The magnitudes of these sensitivities can provide guidance for identifying appropriate modeling assumptions for thermal evaluations extending long term storage out beyond 50, 100, 200, and 300 years.
Date: August 15, 2013
Creator: Cuta, Judith M.; Suffield, Sarah R.; Fort, James A. & Adkins, Harold E.
Object Type: Report
System: The UNT Digital Library
Top Quark Anomalous Couplings at the International Linear Collider (open access)

Top Quark Anomalous Couplings at the International Linear Collider

We present a study of the experimental determination of the forward-backward asymmetry in the process e{sup +}e{sup -} {yields} t{bar t} and in the subsequent t {yields} Wb decay, studied in the context of the International Linear Collider. This process probes the elementary couplings of the top quark to the photon, the Z and the W bosons at a level of precision that is difficult to achieve at hadron colliders. Measurement of the forward-backward asymmetry requires excellent b quark identification and determination of the quark charge. The study reported here is performed in the most challenging all-hadronic channel e{sup +}e{sup -} {yields} b{bar b}q{bar q}q{bar q}. It includes realistic details of the experimental environment, a full Monte Carlo simulation of the detector, based on the Silicon Detector concept, and realistic event reconstruction. The forward-backward asymmetries are determined to a precision of approximately 1% for each of two choices of beam polarization. We analyze the implications for the determination of the t{bar t}Z and Wt{bar b} couplings.
Date: August 15, 2011
Creator: Devetak, Erik; Nomerotski, Andrei & Peskin, Michael
Object Type: Article
System: The UNT Digital Library
Environmental Protection Agency (EPA): Appropriations for FY2014 in P.L. 113-76 (open access)

Environmental Protection Agency (EPA): Appropriations for FY2014 in P.L. 113-76

This report presents a discussion of the FY2014 enacted appropriations for selected EPA programs and activities highlighted in the congressional debate.
Date: August 15, 2014
Creator: Esworthy, Robert & Bearden, David M.
Object Type: Report
System: The UNT Digital Library
Enforcing Building Energy Codes in China: Progress and Comparative Lessons (open access)

Enforcing Building Energy Codes in China: Progress and Comparative Lessons

From 1995 to 2005, building energy use in China increased more rapidly than the world average. China has been adding 0.4 to 1.6 billion square meters of floor space annually , making it the world’s largest market for new construction. In fact, by 2020, China is expected to comprise half of all new construction. In response to this, China has begun to make important steps towards achieving building energy efficiency, including the implementation of building energy standards that requires new buildings to be 65% more efficient than buildings from the early 1980s. Making progress on reducing building energy use requires both a comprehensive code and a robust enforcement system. The latter – the enforcement system – is a particularly critical component for assuring that a building code has an effect. China has dramatically enhanced its enforcement system in the past two years, with more detailed requirements for ensuring enforcement and new penalties for non-compliance. We believe that the U.S. and other developed countries could benefit from learning about the multiple checks and the documentation required in China. Similarly, some of the more user-friendly enforcement approaches developed in the U.S. and elsewhere may be useful for China as it strives to …
Date: August 15, 2010
Creator: Evans, Meredydd; Shui, Bin; Halverson, Mark A. & Delgado, Alison
Object Type: Report
System: The UNT Digital Library
Health Insurance Exchanges Under the Patient Protection and Affordable Care Act (ACA) (open access)

Health Insurance Exchanges Under the Patient Protection and Affordable Care Act (ACA)

This report outlines the required minimum functions of exchanges, and explains how exchanges are expected to be established and administered under ACA.
Date: August 15, 2012
Creator: Fernandez, Bernadette & Mach, Annie L.
Object Type: Report
System: The UNT Digital Library
Metrics For Comparing Plasma Mass Filters (open access)

Metrics For Comparing Plasma Mass Filters

High-throughput mass separation of nuclear waste may be useful for optimal storage, disposal, or environmental remediation. The most dangerous part of nuclear waste is the fission product, which produces most of the heat and medium-term radiation. Plasmas are well-suited to separating nuclear waste because they can separate many different species in a single step. A number of plasma devices have been designed for such mass separation, but there has been no standardized comparison between these devices. We define a standard metric, the separative power per unit volume, and derive it for three different plasma mass filters: the plasma centrifuge, Ohkawa filter, and the magnetic centrifugal mass filter. __________________________________________________
Date: August 15, 2012
Creator: Fetterman, Abraham J. & Fisch, Nathaniel J.
Object Type: Report
System: The UNT Digital Library