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
Nanosensors as Reservoir Engineering Tools to Map Insitu Temperature Distributions in Geothermal Reservoirs (open access)

Nanosensors as Reservoir Engineering Tools to Map Insitu Temperature Distributions in Geothermal Reservoirs

The feasibility of using nanosensors to measure temperature distribution and predict thermal breakthrough in geothermal reservoirs is addressed in this report. Four candidate sensors were identified: melting tin-bismuth alloy nanoparticles, silica nanoparticles with covalently-attached dye, hollow silica nanoparticles with encapsulated dye and impermeable melting shells, and dye-polymer composite time-temperature indicators. Four main challenges associated with the successful implementation of temperature nanosensors were identified: nanoparticle mobility in porous and fractured media, the collection and detection of nanoparticles at the production well, engineering temperature sensing mechanisms that are both detectable and irreversible, and inferring the spatial geolocation of temperature measurements in order to map temperature distribution. Initial experiments were carried out to investigate each of these challenges. It was demonstrated in a slim-tube injection experiment that it is possible to transport silica nanoparticles over large distances through porous media. The feasibility of magnetic collection of nanoparticles from produced fluid was evaluated experimentally, and it was estimated that 3% of the injected nanoparticles were recovered in a prototype magnetic collection device. An analysis technique was tailored to nanosensors with a dye-release mechanism to estimate temperature measurement geolocation by analyzing the return curve of the released dye. This technique was used in a hypothetical …
Date: June 15, 2011
Creator: Ames, Morgan.
Object Type: Report
System: The UNT Digital Library
Recent Developments in SHERPA (open access)

Recent Developments in SHERPA

Some recent QCD-related developments in the SHERPA event generator are presented. In the past decades, event generators such as PYTHIA [1, 2] and HERWIG [3, 4] have been central for nearly all physics analyses at particle physics experiments at the high-energy frontier. This will also hold true at the LHC, where a large number of interesting signals for new particles or new phenomena (the Higgs boson or any other manifestation of the mechanism behind electro-weak symmetry breaking, supersymmetry, extra dimensions etc.) is hampered by a plethora of severe, sometimes overwhelming backgrounds. Nearly all of them are largely influenced by QCD. Therefore it seems fair to say that the success of the LHC in finding new physics may very well depend on a deep and detailed understanding of old physics, like QCD. Examples for this include, among others, the central-jet veto for the vector boson fusion channel for Higgs production or topologies, where gauge bosons emerge in association with many jets, a background for many search channels. In a reflection on increased needs by the experimental community, aiming at higher precision, incorporation of new physics models and so on, the work horses of old have undergone serious renovation efforts, resulting in …
Date: November 15, 2011
Creator: Archibald, Jennifer; Gleisberg, Tanju; Hoeche, Stefan; Krauss, Frank; Schonherr, Marek; Schumann, Steffen et al.
Object Type: Article
System: The UNT Digital Library
U.S. Department of Energy Clean Cities Five-Year Strategic Plan (open access)

U.S. Department of Energy Clean Cities Five-Year Strategic Plan

Clean Cities is a government-industry partnership sponsored by the U.S. Department of Energy's (DOE) Vehicle Technologies Program, which is part of the Office of Energy Efficiency and Renewable Energy. Working with its network of about 100 local coalitions and more than 6,500 stakeholders across the country, Clean Cities delivers on its mission to reduce petroleum consumption in on-road transportation. In its work to reduce petroleum use, Clean Cities focuses on a portfolio of technologies that includes electric drive, propane, natural gas, renewable natural gas/biomethane, ethanol/E85, biodiesel/B20 and higher-level blends, fuel economy, and idle reduction. Over the past 17 years, Clean Cities coalitions have displaced more than 2.4 billion gallons of petroleum; they are on track to displace 2.5 billion gallons of gasoline per year by 2020. This Clean Cities Strategic Plan lays out an aggressive five-year agenda to help DOE Clean Cities and its network of coalitions and stakeholders accelerate the deployment of alternative fuel and advanced technology vehicles, while also expanding the supporting infrastructure to reduce petroleum use. Today, Clean Cities has a far larger opportunity to make an impact than at any time in its history because of its unprecedented $300 million allocation for community-based deployment projects from …
Date: February 15, 2011
Creator: Associates, Cambridge Concord
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
Genetic manipulation of the obligate chemolithoautotrophic bacterium Thiobacillus denitrificans (open access)

Genetic manipulation of the obligate chemolithoautotrophic bacterium Thiobacillus denitrificans

Chemolithoautotrophic bacteria can be of industrial and environmental importance, but they present a challenge for systems biology studies, as their central metabolism deviates from that of model organisms and there is a much less extensive experimental basis for their gene annotation than for typical organoheterotrophs. For microbes with sequenced genomes but unconventional metabolism, the ability to create knockout mutations can be a powerful tool for functional genomics and thereby render an organism more amenable to systems biology approaches. In this chapter, we describe a genetic system for Thiobacillus denitrificans, with which insertion mutations can be introduced by homologous recombination and complemented in trans. Insertion mutations are generated by in vitro transposition, the mutated genes are amplified by the PCR, and the amplicons are introduced into T. denitrificans by electroporation. Use of a complementation vector, pTL2, based on the IncP plasmid pRR10 is also addressed.
Date: July 15, 2011
Creator: Beller, H.R.; Legler, T.C. & Kane, S.R.
Object Type: Article
System: The UNT Digital Library
OpenMP for Accelerators (open access)

OpenMP for Accelerators

OpenMP [13] is the dominant programming model for shared-memory parallelism in C, C++ and Fortran due to its easy-to-use directive-based style, portability and broad support by compiler vendors. Similar characteristics are needed for a programming model for devices such as GPUs and DSPs that are gaining popularity to accelerate compute-intensive application regions. This paper presents extensions to OpenMP that provide that programming model. Our results demonstrate that a high-level programming model can provide accelerated performance comparable to hand-coded implementations in CUDA.
Date: March 15, 2011
Creator: Beyer, J C; Stotzer, E J; Hart, A & de Supinski, B R
Object Type: Article
System: The UNT Digital Library
New Prospects in High Energy Astrophysics (open access)

New Prospects in High Energy Astrophysics

Recent discoveries using TeV, X-ray and radio telescopes as well as Ultra High Energy Cosmic Ray arrays are leading to new insights into longstanding puzzles in high energy astrophysics. Many of these insights come from combining observations throughout the electromagnetic and other spectra as well as evidence assembled from different types of source to propose general principles. Issues discussed in this general overview include methods of accelerating relativistic particles, and amplifying magnetic field, the dynamics of relativistic outflows and the nature of the prime movers that power them. Observational approaches to distinguishing hadronic, leptonic and electromagnetic outflows and emission mechanisms are discussed along with probes of the velocity field and the confinement mechanisms. Observations with GLAST promise to be very prescriptive for addressing these problems.
Date: November 15, 2011
Creator: Blandford, Roger
Object Type: Article
System: The UNT Digital Library
Implementation and Performance of the Tau Trigger in the ATLAS Experiment (open access)

Implementation and Performance of the Tau Trigger in the ATLAS Experiment

Triggering on hadronic taus at the LHC is a difficult task due to the high rate and occupancy of the events. On the other hand, the tau trigger increases the discovery potential of ATLAS in many physics channels, among others the Standard Model or SuperSymmetric Higgs (charged or neutrals) production. In order to cope with the rate and optimize the efficiency on important physics channels, the results of the current simulation studies indicate that the ATLAS tau trigger should be used either with relatively high transverse momentum thresholds alone, or with more relaxed threshold requirements in combination with other triggers, like the missing transverse energy trigger or a leptonic or jet trigger. In this contribution we describe the ATLAS tau trigger, and we present some of the current results from the simulation studies, focusing both on early physics and on physics at high luminosity.
Date: November 15, 2011
Creator: Bosman, M.; Casado, P.; /Barcelona, IFAE; Dam, M.; U., /Copenhagen; Demers, S. et al.
Object Type: Article
System: The UNT Digital Library
Experimental Investigation of Excited-State Lifetimes in Atomic Ytterbium (open access)

Experimental Investigation of Excited-State Lifetimes in Atomic Ytterbium

Lifetimes of 21 excited states in atomic Yb were measured using time-resolved fluorescence detection following pulsed laser excitation. The lifetime of the 4f{sup 14}5d6s {sup 3}D{sub 1} state, which is of particular importance for a proposed study of parity nonconservation in atoms, was measured to be 380(30) ns.
Date: November 15, 2011
Creator: Bowers, C. J.; Budker, D.; Commins, E. D.; DeMille, D.; Freedman, S. J.; Nguyen, A. -T. et al.
Object Type: Article
System: The UNT Digital Library
Warm Water Oxidation Verification - Scoping and Stirred Reactor Tests (open access)

Warm Water Oxidation Verification - Scoping and Stirred Reactor Tests

Scoping tests to evaluate the effects of agitation and pH adjustment on simulant sludge agglomeration and uranium metal oxidation at {approx}95 C were performed under Test Instructions(a,b) and as per sections 5.1 and 5.2 of this Test Plan prepared by AREVA. (c) The thermal testing occurred during the week of October 4-9, 2010. The results are reported here. For this testing, two uranium-containing simulant sludge types were evaluated: (1) a full uranium-containing K West (KW) container sludge simulant consisting of nine predominant sludge components; (2) a 50:50 uranium-mole basis mixture of uraninite [U(IV)] and metaschoepite [U(VI)]. This scoping study was conducted in support of the Sludge Treatment Project (STP) Phase 2 technology evaluation for the treatment and packaging of K-Basin sludge. The STP is managed by CH2M Hill Plateau Remediation Company (CHPRC) for the U.S. Department of Energy. Warm water ({approx}95 C) oxidation of sludge, followed by immobilization, has been proposed by AREVA and is one of the alternative flowsheets being considered to convert uranium metal to UO{sub 2} and eliminate H{sub 2} generation during final sludge disposition. Preliminary assessments of warm water oxidation have been conducted, and several issues have been identified that can best be evaluated through laboratory …
Date: June 15, 2011
Creator: Braley, Jenifer C.; Sinkov, Sergey I.; Delegard, Calvin H. & Schmidt, Andrew J.
Object Type: Report
System: The UNT Digital Library
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
Evaluation of sustained release polylactate electron donors for removal of hexavalent chromium from contaminated groundwater (open access)

Evaluation of sustained release polylactate electron donors for removal of hexavalent chromium from contaminated groundwater

To evaluate the efficacy of bioimmobilization of Cr(VI) in groundwater at the Department of Energy Hanford site, we conducted a series of microcosm experiments using a range of commercial electron donors with varying degrees of lactate polymerization (polylactate). These experiments were conducted using Hanford Formation sediments (coarse sand and gravel) immersed in Hanford groundwater, which were amended with Cr(VI) and several types of lactate-based electron donors (Hydrogen Release Compound, HRC; primer-HRC, pHRC; extended release HRC) and the polylactate-cysteine form (Metal Remediation Compound, MRC). The results showed that polylactate compounds stimulated an increase in bacterial biomass and activity to a greater extent than sodium lactate when applied at equivalent carbon concentrations. At the same time, concentrations of headspace hydrogen and methane increased and correlated with changes in the microbial community structure. Enrichment of Pseudomonas spp. occurred with all lactate additions, and enrichment of sulfate-reducing Desulfosporosinus spp. occurred with almost complete sulfate reduction. The results of these experiments demonstrate that amendment with the pHRC and MRC forms result in effective removal of Cr(VI) from solution most likely by both direct (enzymatic) and indirect (microbially generated reductant) mechanisms.
Date: February 15, 2011
Creator: Brodie, E. L.; Joyner, D. C.; Faybishenko, B.; Conrad, M. E.; Rios-Velazquez, C.; Mork, B. et al.
Object Type: Article
System: The UNT Digital Library
Recent Developments in Dynamic Transmission Electron Microscopy (open access)

Recent Developments in Dynamic Transmission Electron Microscopy

None
Date: April 15, 2011
Creator: Browning, N D; Bonds, M A; Campbell, G H; Evans, J E; LaGrange, T; Jungjohann, K L et al.
Object Type: Article
System: The UNT Digital Library
2011 Organometallic Chemistry (July 10-15, 2011, Salve Regina University, Newport, RI) (open access)

2011 Organometallic Chemistry (July 10-15, 2011, Salve Regina University, Newport, RI)

Organometallic chemistry has played and will continue to play a significant role in helping us understand the way bonds are made or broken in the presence of a transition metal complex. Current challenges range from the efficient exploitation of energy resources to the creative use of natural and artificial enzymes. Most of the new advances in the area are due to our extended understanding of processes at a molecular level due to new mechanistic studies, techniques to detect reaction intermediates and theory. The conference will bring the most recent advances in the field including nanocatalysis, surface organometallic chemistry, characterization techniques, new chemical reactivity and theoretical approaches along with applications to organic synthesis and the discovery of new materials. The Conference will bring together a collection of investigators who are at the forefront of their field, and will provide opportunities for junior scientists and graduate students to present their work in poster format and exchange ideas with leaders in the field. Six outstanding posters will be selected for short talks. The collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to …
Date: July 15, 2011
Creator: Bunel, Dr. Emilio
Object Type: Article
System: The UNT Digital Library
Ground Model Options in the NEC-4.2 Antenna Code (open access)

Ground Model Options in the NEC-4.2 Antenna Code

None
Date: June 15, 2011
Creator: Burke, G J
Object Type: Report
System: The UNT Digital Library
Report on fact finding visit to Texas A&M Cyclotron Institute (open access)

Report on fact finding visit to Texas A&M Cyclotron Institute

None
Date: July 15, 2011
Creator: Burke, J T; Ressler, J J & Scielzo, N D
Object Type: Report
System: The UNT Digital Library
USE OF THE AERIAL MEASUREMENT SYSTEM HELICOPTER EMERGENCY RESPONSE ACQUISITION SYSTEMS WITH GEOGRAPHIC INFORMATION SYSTEM FOR RADIOACTIVE SOIL REMEDIATION - [11504] (open access)

USE OF THE AERIAL MEASUREMENT SYSTEM HELICOPTER EMERGENCY RESPONSE ACQUISITION SYSTEMS WITH GEOGRAPHIC INFORMATION SYSTEM FOR RADIOACTIVE SOIL REMEDIATION - [11504]

The Aerial Measurement System (AMS) Helicopter Emergency Response Acquisition System provides a thorough and economical means to identify and characterize the contaminants for large area radiological surveys. The helicopter system can provide a 100-percent survey of an area that qualifies as a scoping survey under the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) methodology. If the sensitivity is adequate when compared to the clean up values, it may also be used for the characterization survey. The data from the helicopter survey can be displayed and manipulated to provide invaluable data during remediation activities.
Date: February 15, 2011
Creator: CT, BROCK
Object Type: Article
System: The UNT Digital Library
Composition, stability, and measurement of reduced uranium phases for groundwater bioremediation at Old Rifle, CO (open access)

Composition, stability, and measurement of reduced uranium phases for groundwater bioremediation at Old Rifle, CO

Reductive biostimulation is currently being explored as a possible remediation strategy for uranium (U) contaminated groundwater, and is currently being investigated at a field site in Rifle, CO, USA. The long-term stability of the resulting U(IV) phases is a key component of the overall performance and depends upon a variety of factors, including rate and mechanism of reduction, mineral associations in the subsurface, and propensity for oxidation. To address these factors, several approaches were used to evaluate the redox sensitivity of U: measurement of the rate of oxidative dissolution of biogenic uraninite (UO{sub 2(s)}) deployed in groundwater at Rifle, characterization of a zone of natural bioreduction exhibiting relevant reduced mineral phases, and laboratory studies of the oxidative capacity of Fe(III) and reductive capacity of Fe(II) with regard to U(IV) and U(VI), respectively.
Date: October 15, 2011
Creator: Campbell, K. M.; Davis, J. A.; Bargar, J.; Giammar, D.; Bernier-Latmani, R.; Kukkadapu, R. et al.
Object Type: Article
System: The UNT Digital Library
Impact of CO2 geological sequestration on the nucleation of earthquakes (open access)

Impact of CO2 geological sequestration on the nucleation of earthquakes

None
Date: July 15, 2011
Creator: Cappa, F. & Rutqvist, J.
Object Type: Article
System: The UNT Digital Library
SLUDGE TREATMENT PROJECT ENGINEERED CONTAINER RETRIEVAL AND TRANSFER SYSTEM PRELMINARY DESIGN HAZARD AND OPERABILITY STUDY (open access)

SLUDGE TREATMENT PROJECT ENGINEERED CONTAINER RETRIEVAL AND TRANSFER SYSTEM PRELMINARY DESIGN HAZARD AND OPERABILITY STUDY

This Hazard and Operability (HAZOP) study addresses the Sludge Treatment Project (STP) Engineered Container Retrieval and Transfer System (ECRTS) preliminary design for retrieving sludge from underwater engineered containers located in the 105-K West (KW) Basin, transferring the sludge as a sludge-water slurry (hereafter referred to as 'slurry') to a Sludge Transport and Storage Container (STSC) located in a Modified KW Basin Annex, and preparing the STSC for transport to T Plant using the Sludge Transport System (STS). There are six, underwater engineered containers located in the KW Basin that, at the time of sludge retrieval, will contain an estimated volume of 5.2 m{sup 3} of KW Basin floor and pit sludge, 18.4 m{sup 3} of 105-K East (KE) Basin floor, pit, and canister sludge, and 3.5 m{sup 3} of settler tank sludge. The KE and KW Basin sludge consists of fuel corrosion products (including metallic uranium, and fission and activation products), small fuel fragments, iron and aluminum oxide, sand, dirt, operational debris, and biological debris. The settler tank sludge consists of sludge generated by the washing of KE and KW Basin fuel in the Primary Clean Machine. A detailed description of the origin of sludge and its chemical and physical …
Date: July 15, 2011
Creator: Carro, C. A.
Object Type: Report
System: The UNT Digital Library
Use of immunomagnetic separation for the detection of Desulfovibrio vulgaris from environmental samples (open access)

Use of immunomagnetic separation for the detection of Desulfovibrio vulgaris from environmental samples

Immunomagnetic separation (IMS) has proved highly efficient for recovering microorganisms from heterogeneous samples. Current investigation targeted the separation of viable cells of the sulfate-reducing bacterium, Desulfovibrio vulgaris. Streptavidin-coupled paramagnetic beads and biotin labeled antibodies raised against surface antigens of this microorganism were used to capture D. vulgaris cells in both bioreactor grown laboratory samples and from extremely low-biomass environmental soil and subsurface drilling samples. Initial studies on detection, recovery efficiency and viability for IMS were performed with laboratory grown D. vulgaris cells using various cell densities. Efficiency of cell isolation and recovery (i.e., release of the microbial cells from the beads following separation) was followed by microscopic imaging and acridine orange direct counts (AODC). Excellent recovery efficiency encouraged the use of IMS to capture Desulfovibrio spp. cells from low-biomass environmental samples. The environmental samples were obtained from a radionuclide-contaminated site in Germany and the chromium (VI)-contaminated Hanford site, an ongoing bioremediation project of the U.S. Department of Energy. Field deployable IMS technology may greatly facilitate environmental sampling and bioremediation process monitoring and enable transcriptomics and proteomics/metabolomics-based studies directly on cells collected from the field.
Date: April 15, 2011
Creator: Chakraborty, R.; Hazen, T. C.; Joyner, D. C.; Kusel, K.; Singer, M. E.; Sitte, J. et al.
Object Type: Article
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