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Alignment validation (open access)

Alignment validation

The four experiments, ALICE, ATLAS, CMS and LHCb are currently under constructionat CERN. They will study the products of proton-proton collisions at the Large Hadron Collider. All experiments are equipped with sophisticated tracking systems, unprecedented in size and complexity. Full exploitation of both the inner detector andthe muon system requires an accurate alignment of all detector elements. Alignmentinformation is deduced from dedicated hardware alignment systems and the reconstruction of charged particles. However, the system is degenerate which means the data is insufficient to constrain all alignment degrees of freedom, so the techniques are prone to converging on wrong geometries. This deficiency necessitates validation and monitoring of the alignment. An exhaustive discussion of means to validate is subject to this document, including examples and plans from all four LHC experiments, as well as other high energy experiments.
Date: September 6, 2008
Creator: ALICE; ATLAS; CMS; LHCb & Golling, Tobias
System: The UNT Digital Library
Reconfigurable mobile manipulation for accident response (open access)

Reconfigurable mobile manipulation for accident response

The need for a telerobotic vehicle with hazard sensing and integral manipulation capabilities has been identified for use in transportation accidents where nuclear weapons are involved. The Accident Response Mobile Manipulation System (ARMMS) platform has been developed to provide remote dexterous manipulation and hazard sensing for the Accident Response Group (ARG) at Sandia National Laboratories. The ARMMS' mobility platform is a military HMMWV [High Mobility Multipurpose Wheeled Vehicle] that is teleoperated over RF or Fiber Optic communication channels. ARMMS is equipped with two high strength Schilling Titan II manipulators and a suite of hazardous gas and radiation sensors. Recently, a modular telerobotic control architecture call SMART (Sandia Modular Architecture for Robotic and Teleoperation) has been applied to ARMMS. SMART enables input devices and many system behaviors to be rapidly configured in the field for specific mission needs. This paper summarizes current SMART developments applied to ARMMS.
Date: June 6, 2000
Creator: ANDERSON,ROBERT J.; MORSE,WILLIAM D.; SHIREY,DAVID L.; CDEBACA,DANIEL M.; HOFFMAN JR.,JOHN P. & LUCY,WILLIAM E.
System: The UNT Digital Library
Measurement of $D^{* /-}$ Meson Production in Jets from Pp Collisions at Sqrt(S) = 7 TeV with the ATLAS Detector (open access)

Measurement of $D^{* /-}$ Meson Production in Jets from Pp Collisions at Sqrt(S) = 7 TeV with the ATLAS Detector

None
Date: May 6, 2013
Creator: Aad, Georges
System: The UNT Digital Library
Mass, quark-number, and sqrt sNN dependence of the second andfourth flow harmonics in ultra-relativistic nucleus-nucleuscollisions (open access)

Mass, quark-number, and sqrt sNN dependence of the second andfourth flow harmonics in ultra-relativistic nucleus-nucleuscollisions

We present STAR measurements of the azimuthal anisotropyparameter v_2 for pions, kaons, protons, Lambda, bar Lambda, Xi+bar Xi,and \Omega + bar Omega, along with v_4 for pions, kaons, protons, andLambda + bar Lambda at mid-rapidity for Au+Au collisions at sqrt sNN=62.4and 200 GeV. The v_2(p_T) values for all hadron species at 62.4 GeV aresimilar to those observed in 130 and 200 GeV collisions. For observedkinematic ranges, v_2 values at 62.4, 130, and 200 GeV are as little as10 percent-15 percent larger than those in Pb+Pb collisions at sqrt s NN=17.3 GeV. At intermediate transverse momentum (p_T from 1.5-5 GeV/c),the 62.4 GeV v_2(p_T) and v_4(p_T) values are consistent with thequark-number scaling first observed at 200 GeV. A four-particle cumulantanalysis is used to assess the non-flow contributions to pions andprotons and some indications are found for a smaller non-flowcontribution to protons than pions. Baryon v_2 is larger than anti-baryonv_2 at 62.4 and 200 GeV perhaps indicating either that the initialspatial net-baryon distribution is anisotropic, that the mechanismleading to transport of baryon number from beam- to mid-rapidity enhancesv_2, or that anti-baryon and baryon annihilation is larger in thein-plane direction.
Date: January 6, 2007
Creator: Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett,J.; Anderson, B. D. et al.
System: The UNT Digital Library
SHIPMENT OF TWO DOE-STD-3013 CONTAINERS IN A 9977 TYPE B PACKAGE (open access)

SHIPMENT OF TWO DOE-STD-3013 CONTAINERS IN A 9977 TYPE B PACKAGE

The 9977 is a certified Type B Packaging authorized to ship uranium and plutonium in metal and oxide forms. Historically, the standard container for these materials has been the DOE-STD-3013 which was specifically designed for the long term storage of plutonium bearing materials. The Department of Energy has used the 9975 Packaging containing a single 3013 container for the transportation and storage of these materials. In order to reduce container, shipping, and storage costs, the 9977 Packaging is being certified for transportation and storage of two 3013 containers. The challenges and risks of this content and the 9977s ability to meet the Code of Federal Regulations for the transport of these materials are presented.
Date: June 6, 2011
Creator: Abramczyk, G.; Bellamy, S.; Loftin, B. & Nathan, S.
System: The UNT Digital Library
SHIPMENT OF NON-TRADITIONAL CONTENTS IN THE 9977 TYPE B PACKAGE (open access)

SHIPMENT OF NON-TRADITIONAL CONTENTS IN THE 9977 TYPE B PACKAGE

The 9977 is a certified Type B Packaging authorized to ship uranium and plutonium in metal and oxide forms. These materials are typically confined within metallic containers designed for ease of handling and to prevent the spread of contamination. The Pacific Northwest National Laboratory (PNNL) uses Pu and U sources for the training of domestic and international customs agents in the identification and detection of radioactive materials (RAM). These materials are packed in polycarbonate containers which permit the trainees to view the RAM. The safety basis was made to authorize the use of these unusual containers. The inclusion of the PNNL Training Source Contents into the 9977 Packaging imposed unique conditions previously unanalyzed. The use of polycarbonate as a content container material, while different from any configuration previously considered, does not raise any safety issues with the package which continues to operate with a large safety margin for temperatures, pressures, containment, dose rates, and subcriticality.
Date: June 6, 2011
Creator: Abramczyk, G.; Loftin, B.; Bellamy, S. & Nathan, S.
System: The UNT Digital Library
RECLAMATION OF RADIOACTIVE MATERIAL PACKAGING COMPONENTS (open access)

RECLAMATION OF RADIOACTIVE MATERIAL PACKAGING COMPONENTS

Radioactive material packages are withdrawn from use for various reasons; loss of mission, decertification, damage, replacement, etc. While the packages themselves may be decertified, various components may still be able to perform to their required standards and find useful service. The Packaging Technology and Pressurized Systems group of the Savannah River National Laboratory has been reducing the cost of producing new Type B Packagings by reclaiming, refurbishing, and returning to service the containment vessels from older decertified packagings. The program and its benefits are presented.
Date: June 6, 2011
Creator: Abramczyk, G.; Nathan, S.; Loftin, B. & Bellamy, S.
System: The UNT Digital Library
Status of EXO-200 (open access)

Status of EXO-200

EXO-200 is the first phase of the Enriched Xenon Observatory (EXO) experiment, which searches for neutrinoless double beta decay in {sup 136}Xe to measure the mass and probe the Majorana nature of the neutrino. EXO-200 consists of 200 kg of liquid Xe enriched to 80% in {sup 136}Xe in an ultra-low background TPC. Energy resolution is enhanced through the simultaneous collection of scintillation light using Large Area Avalanche Photodiodes (LAAPD's) and ionization charge. It is being installed at the WIPP site in New Mexico, which provides a 2000 meter water-equivalent overburden. EXO-200 will begin taking data in 2009, with the expected two-year sensitivity to the half-life for neutrinoless double beta decay of 6.4 x 10{sup 25} years. According to the most recent nuclear matrix element calculations, this corresponds to an effective Majorana neutrino mass of 0.13 to 0.19 eV. It will also measure the two neutrino mode for the first time in {sup 136}Xe.
Date: December 6, 2011
Creator: Ackerman, Nicole
System: The UNT Digital Library
Commentary on “Extended Hildebrand Approach: An Empirical Model for Solubility Prediction of Etodolac in 1,4-Dioxane and Water Mixtures” (open access)

Commentary on “Extended Hildebrand Approach: An Empirical Model for Solubility Prediction of Etodolac in 1,4-Dioxane and Water Mixtures”

This article provides a commentary on mathematical errors concerning the incorrect conversion of mass fraction to volume fraction concentrations of 1,4-dioxane, the incorrect conversion of mole fraction solubilities to molar solubilities of Etodolac, and the incorrect calculation of the ideal mole fraction solubility of Etodolac.
Date: November 6, 2017
Creator: Acree, William E. (William Eugene)
System: The UNT Digital Library
Identified particle distributions in pp and Au+Au collisions atsqrt sNN=200 GeV (open access)

Identified particle distributions in pp and Au+Au collisions atsqrt sNN=200 GeV

Transverse mass and rapidity distributions for charged pions, charged kaons, protons and antiprotons are reported for {radical}sNN = 200 GeV pp and Au+Au collisions at RHIC. The transverse mass distributions are rapidity independent within |y| < 0.5, consistent with a boost-invariant system in this rapidity interval. Spectral shapes and relative particle yields are similar in pp and peripheral Au+Au collisions and change smoothly to central Au+Au collisions. No centrality dependence was observed in the kaon and antiproton production rates relative to the pion production rate from medium-central to central collisions. Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and relatively long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.
Date: October 6, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
System: The UNT Digital Library
High power density and bias-free reverse electrowetting energy harvesting using surface area enhanced porous electrodes (open access)

High power density and bias-free reverse electrowetting energy harvesting using surface area enhanced porous electrodes

Article presents a novel approach for enhancing power output from a REWOD energy harvester by significantly increasing the total available surface area using perforated silicon wafer electrodes.
Date: November 6, 2021
Creator: Adhikari, Pashupati R.; Reid, Russell C. & Mahbub, Ifana
System: The UNT Digital Library
Results from the CLIC X-Band Structure Test Program at NLCTA (open access)

Results from the CLIC X-Band Structure Test Program at NLCTA

As part of a SLAC-CERN-KEK collaboration on high gradient X-band structure research, several prototype structures for the CLIC linear collider study have been tested using two of the high power (300 MW) X-band rf stations in the NLCTA facility at SLAC. These structures differ in terms of their fabrication (brazed disks and clamped quadrants), gradient profile (amount by which the gradient increases along the structure, which optimizes efficiency and maximizes sustainable gradient) and HOM damping (use of slots or waveguides to rapidly dissipate dipole mode energy). The CLIC goal in the next few years is to demonstrate the feasibility of a CLIC-ready baseline design and to investigate alternatives that could increase efficiency. This paper summarizes the high gradient test results from NLCTA in support of this effort.
Date: July 6, 2009
Creator: Adolphsen, Chris; Bowden, Gordon; Dolgashev, Valery; Laurent, Lisa; Tantawi, Sami; Wang, Faya et al.
System: The UNT Digital Library
Geometric metastability, quivers and holography (open access)

Geometric metastability, quivers and holography

We use large N duality to study brane/anti-brane configurations on a class of Calabi-Yau manifolds. With only branes present, the Calabi-Yau manifolds in question give rise to N=2 ADE quiver theories deformed by superpotential terms. We show that the large N duality conjecture of hep-th/0610249 reproduces correctly the known qualitative features of the brane/anti-brane physics. In the supersymmetric case, the gauge theories have Seiberg dualities which are represented as flops in the geometry. Moreover, the holographic dual geometry encodes the whole RG flow of the gauge theory. In the non-supersymmetric case, the large N duality predicts that the brane/anti-brane theories also enjoy such dualities, and allows one to pick out the good description at a given energy scale.
Date: September 6, 2007
Creator: Aganagic, Mina; Aganagic, Mina; Beem, Christopher & Freivogel, Ben
System: The UNT Digital Library
A new security model for collaborative environments (open access)

A new security model for collaborative environments

Prevalent authentication and authorization models for distributed systems provide for the protection of computer systems and resources from unauthorized use. The rules and policies that drive the access decisions in such systems are typically configured up front and require trust establishment before the systems can be used. This approach does not work well for computer software that moderates human-to-human interaction. This work proposes a new model for trust establishment and management in computer systems supporting collaborative work. The model supports the dynamic addition of new users to a collaboration with very little initial trust placed into their identity and supports the incremental building of trust relationships through endorsements from established collaborators. It also recognizes the strength of a users authentication when making trust decisions. By mimicking the way humans build trust naturally the model can support a wide variety of usage scenarios. Its particular strength lies in the support for ad-hoc and dynamic collaborations and the ubiquitous access to a Computer Supported Collaboration Workspace (CSCW) system from locations with varying levels of trust and security.
Date: June 6, 2003
Creator: Agarwal, Deborah; Lorch, Markus; Thompson, Mary & Perry, Marcia
System: The UNT Digital Library
LHC Signals from Warped Extra Dimensions (open access)

LHC Signals from Warped Extra Dimensions

We study production of Kaluza-Klein gluons (KKG) at the Large Hadron Collider (LHC) in the framework of a warped extra dimension with the Standard Model (SM) fields propagating in the bulk. We show that the detection of KK gluon is challenging since its production is suppressed by small couplings to the proton's constituents. Moreover, the KK gluon decaysmostly to top pairs due to an enhanced coupling and hence is broad. Nevertheless, we demonstrate that for MKKG<~;; 4 TeV, 100 fb-1 of data at the LHC can provide discovery of the KK gluon. We utilize a sizeable left-right polarization asymmetry from the KK gluon resonance to maximize the signal significance, and we explore the novel feature of extremely highly energetic"top-jets." We briefly discuss how the detection of electroweak gauge KK states (Z/W) faces a similar challenge since their leptonic decays ("golden" modes) are suppressed. Our analysis suggests that other frameworks, for example little Higgs, which rely on UV completion via strong dynamics might face similar challenges, namely (1) Suppressed production rates for the new particles (such as Z'), due to their"lightfermion-phobic" nature, and (2) Difficulties in detection since the new particles are broad and decay predominantly to third generation quarks and …
Date: December 6, 2006
Creator: Agashe, K.; Belyaev, A.; Krupovnickas, T.; Perez, G. & Virzi, J.
System: The UNT Digital Library
Thoughts and ''Facts'' From the Ags Polarized Proton Runs During the 1980s. (open access)

Thoughts and ''Facts'' From the Ags Polarized Proton Runs During the 1980s.

This workshop's focus is on considering ways for improving the proton beam polarization that the AGS delivers to the RHIC. This talk attempts to review the first decade of AGS polarization--the 1980's; to briefly describe some aspects of the machine situation, the depolarization avoidance strategies employed and the success achieved in AGS from the perspective of one of those involved.
Date: November 6, 2002
Creator: Ahrens, L.
System: The UNT Digital Library
Effect of thin-film coating on wear in EGR-contaminated oil. (open access)

Effect of thin-film coating on wear in EGR-contaminated oil.

Increased use of higher-efficiency compression ignition direct injection (CIDI) diesel engines instead of today's gasoline engines will result in reduced fuel consumption and greenhouse gases emissions. However, NO{sub x} and particulate exhaust emissions from diesel engines must be significantly reduced due to their possible adverse health effects. Exhaust gas recirculation (EGR) is an effective way to reduce NO{sub x} emissions from diesel engines, but the particulates and acidic exhaust products in the recirculated gas will contaminate engine lubricant oil by increasing the soot content and total acid number (TAN). These factors will increase the wear rate in many critical engine components and seriously compromise engine durability. We have investigated the use of commercially available thin and hard coatings (TiN, TiCN, TiAlN, and CrN) to mitigate the negative effects of EGR on wear. In tests with the four-ball machine according to ASTM D4172, we found that all the four coatings deposited on M-50 steel significantly reduced wear in EGR-contaminated oils when compared with uncoated M50 steel balls.
Date: December 6, 2001
Creator: Ajayi, O. O.; Aldajah, S. H.; Erdemir, A. & Fenske, G. R.
System: The UNT Digital Library
Low-friction coatings for air bearings in fuel cell air compressors (open access)

Low-friction coatings for air bearings in fuel cell air compressors

In an effort to reduce fuel consumption and emissions, hybrid vehicles incorporating fuel cell systems are being developed by automotive manufacturers, their suppliers, federal agencies (specifically, the US Department of Energy) and national laboratories. The fuel cell system will require an air management subsystem that includes a compressor/expander. Certain components in the compressor will require innovative lubrication technology in order to reduce parasitic energy losses and improve their reliability and durability. One such component is the air bearing for air turbocompressors designed and fabricated by Meruit, Inc. Argonne National Laboratory recently developed a carbon-based coating with low friction and wear attributes; this near-frictionless-carbon (NFC) coating is a potential candidate for use in turbocompressor air bearings. The authors present here an evaluation of the Argonne coating for air compressor thrust bearings. With two parallel 440C stainless steel discs in unidirectional sliding contact, the NFC reduced the frictional force four times and the wear rate by more than two orders of magnitude. Wear mechanism on the uncoated surface involved oxidation and production of iron oxide debris. Wear occurred on the coated surfaces primarily by a polishing mechanism.
Date: January 6, 2000
Creator: Ajayi, O. O.; Fenske, G. R.; Erdemir, A.; Woodford, J.; Sitts, J.; Elshot, K. et al.
System: The UNT Digital Library
Performance of amorphous carbon coating in turbocompressor air bearings. (open access)

Performance of amorphous carbon coating in turbocompressor air bearings.

None
Date: December 6, 2001
Creator: Ajayi, O. O.; Woodford, J. B.; Erdemir, A. & Fenske, G. R.
System: The UNT Digital Library
Variable VHE gamma-ray emission from Markarian 501 (open access)

Variable VHE gamma-ray emission from Markarian 501

The blazar Markarian 501 (Mrk 501) was observed at energies above 100 GeV with the MAGIC telescope from May through July 2005. The high sensitivity of the instrument enabled the determination of the flux and spectrum of the source on a night-by-night basis. Throughout our observational campaign, the flux from Mrk 501 was found to vary by an order of magnitude, and to be correlated with spectral changes. Intra-night flux variability with flux-doubling times down to 2 minutes was also observed. The strength of variability increased with the energy of the {gamma}-ray photons. The energy spectra were found to harden significantly with increasing flux, and a spectral peak clearly showed up during very active states. The position of the spectral peak seems to be correlated with the source luminosity.
Date: February 6, 2007
Creator: Albert, Jordi
System: The UNT Digital Library
Searches for Dark Matter Annihilation Signatures in the Segue 1 Satellite Galaxy with the MAGIC-I Telescope (open access)

Searches for Dark Matter Annihilation Signatures in the Segue 1 Satellite Galaxy with the MAGIC-I Telescope

None
Date: June 6, 2013
Creator: Aleksic, J.; Alvarez, E. A.; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Backes, M. et al.
System: The UNT Digital Library
Data-Driven Decision-Making and Its Impacts on Education Quality in Developing Countries: A Systematic Review (open access)

Data-Driven Decision-Making and Its Impacts on Education Quality in Developing Countries: A Systematic Review

Article describes how data-driven decision-making (DDDM) technologies are increasingly being utilized, aiming to enhance education quality. Authors assert that this paper examines articles that explore the implementation of DDDM technologies and their effects on education quality.
Date: November 6, 2023
Creator: Alemneh, Daniel Gelaw; Asfaw, Zelalem & Jimma, Worku
System: The UNT Digital Library
Proposal for an EBIS Based RHIC Preinjector (open access)

Proposal for an EBIS Based RHIC Preinjector

A proposed new heavy ion preinjector for RHIC is described. The progress made at BNL on the development of an Electron Beam Ion Source (EBIS) has increased our confidence that one can build a preinjector meeting RHIC requirements using an EBIS producing intermediate charge state heavy ions. A new RFQ and Linac will be required to accelerate beams from this source to an energy sufficient for injection into the AGS Booster. These are both straightforward devices, very similar to ones already in operation at other laboratories. Injection into the Booster will occur at the same location as the existing heavy ion injection from the Tandem Van de Graaff.
Date: November 6, 2000
Creator: Alessi, J. G.; Beebe, E.; Kponou, A.; Pikin, A.; Prelec, K.; Raparia, D. et al.
System: The UNT Digital Library