AdS/QCD and Applications of Light-Front Holography (open access)

AdS/QCD and Applications of Light-Front Holography

Light-Front Holography leads to a rigorous connection between hadronic amplitudes in a higher dimensional anti-de Sitter (AdS) space and frame-independent light-front wavefunctions of hadrons in 3 + 1 physical space-time, thus providing a compelling physical interpretation of the AdS/CFT correspondence principle and AdS/QCD, a useful framework which describes the correspondence between theories in a modified AdS5 background and confining field theories in physical space-time. To a first semiclassical approximation, where quantum loops and quark masses are not included, this approach leads to a single-variable light-front Schroedinger equation which determines the eigenspectrum and the light-front wavefunctions of hadrons for general spin and orbital angular momentum. The coordinate z in AdS space is uniquely identified with a Lorentz-invariant coordinate {zeta} which measures the separation of the constituents within a hadron at equal light-front time. The internal structure of hadrons is explicitly introduced and the angular momentum of the constituents plays a key role. We give an overview of the light-front holographic approach to strongly coupled QCD. In particular, we study the photon-to-meson transition form factors (TFFs) F{sub M{gamma}}(Q{sup 2}) for {gamma}{gamma}* {yields} M using light-front holographic methods. The results for the TFFs for the {eta} and {eta}' mesons are also presented. Some …
Date: February 16, 2012
Creator: Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Cao, Fu-Guang; U., /Massey; de Teramond, Guy F. & U., /Costa Rica
Object Type: Article
System: The UNT Digital Library
AdS/QCD, Light-Front Holography, and Sublimated Gluons (open access)

AdS/QCD, Light-Front Holography, and Sublimated Gluons

The gauge/gravity duality leads to a simple analytical and phenomenologically compelling nonperturbative approximation to the full light-front QCD Hamiltonian - 'Light-Front Holography', which provides a Lorentz-invariant first-approximation to QCD, and successfully describes the spectroscopy of light-quark meson and baryons, their elastic and transition form factors, and other hadronic properties. The bound-state Schroedinger and Dirac equations of the soft-wall AdS/QCD model predict linear Regge trajectories which have the same slope in orbital angular momentum L and radial quantum number n for both mesons and baryons. Light-front holography connects the fifth-dimensional coordinate of AdS space z to an invariant impact separation variable {zeta} in 3+1 space at fixed light-front time. A key feature is the determination of the frame-independent light-front wavefunctions of hadrons - the relativistic analogs of the Schroedinger wavefunctions of atomic physics which allow one to compute form factors, transversity distributions, spin properties of the valence quarks, jet hadronization, and other hadronic observables. One thus obtains a one-parameter color-confining model for hadron physics at the amplitude level. AdS/QCD also predicts the form of the non-perturbative effective coupling {alpha}{sub s}{sup AdS} (Q) and its {beta}-function with an infrared fixed point which agrees with the effective coupling a{sub g1} (Q{sup 2}) extracted …
Date: February 16, 2012
Creator: Brodsky, Stanley J. & de Teramond, Guy F.
Object Type: Article
System: The UNT Digital Library
ADVANCED COMPOSITE WIND TURBINE BLADE DESIGN BASED ON DURABILITY AND DAMAGE TOLERANCE (open access)

ADVANCED COMPOSITE WIND TURBINE BLADE DESIGN BASED ON DURABILITY AND DAMAGE TOLERANCE

The objective of the program was to demonstrate and verify Certification-by-Analysis (CBA) capability for wind turbine blades made from advanced lightweight composite materials. The approach integrated durability and damage tolerance analysis with robust design and virtual testing capabilities to deliver superior, durable, low weight, low cost, long life, and reliable wind blade design. The GENOA durability and life prediction software suite was be used as the primary simulation tool. First, a micromechanics-based computational approach was used to assess the durability of composite laminates with ply drop features commonly used in wind turbine applications. Ply drops occur in composite joints and closures of wind turbine blades to reduce skin thicknesses along the blade span. They increase localized stress concentration, which may cause premature delamination failure in composite and reduced fatigue service life. Durability and damage tolerance (D&DT) were evaluated utilizing a multi-scale micro-macro progressive failure analysis (PFA) technique. PFA is finite element based and is capable of detecting all stages of material damage including initiation and propagation of delamination. It assesses multiple failure criteria and includes the effects of manufacturing anomalies (i.e., void, fiber waviness). Two different approaches have been used within PFA. The first approach is Virtual Crack Closure Technique …
Date: February 16, 2012
Creator: Abumeri, Galib & Abdi, Frank
Object Type: Report
System: The UNT Digital Library
ADVANCED OXIDATION: OXALATE DECOMPOSITION TESTING WITH OZONE (open access)

ADVANCED OXIDATION: OXALATE DECOMPOSITION TESTING WITH OZONE

At the Savannah River Site (SRS), oxalic acid is currently considered the preferred agent for chemically cleaning the large underground Liquid Radioactive Waste Tanks. It is applied only in the final stages of emptying a tank when generally less than 5,000 kg of waste solids remain, and slurrying based removal methods are no-longer effective. The use of oxalic acid is preferred because of its combined dissolution and chelating properties, as well as the fact that corrosion to the carbon steel tank walls can be controlled. Although oxalic acid is the preferred agent, there are significant potential downstream impacts. Impacts include: (1) Degraded evaporator operation; (2) Resultant oxalate precipitates taking away critically needed operating volume; and (3) Eventual creation of significant volumes of additional feed to salt processing. As an alternative to dealing with the downstream impacts, oxalate decomposition using variations of ozone based Advanced Oxidation Process (AOP) were investigated. In general AOPs use ozone or peroxide and a catalyst to create hydroxyl radicals. Hydroxyl radicals have among the highest oxidation potentials, and are commonly used to decompose organics. Although oxalate is considered among the most difficult organic to decompose, the ability of hydroxyl radicals to decompose oxalate is considered to …
Date: February 29, 2012
Creator: Ketusky, E. & Subramanian, K.
Object Type: Article
System: The UNT Digital Library
Afghanistan Casualties: Military Forces and Civilians (open access)

Afghanistan Casualties: Military Forces and Civilians

This report collects statistics from a variety of sources on casualties sustained during Operation Enduring Freedom (OEF), which began on October 7, 2001, and is ongoing. OEF actions take place primarily in Afghanistan; however, OEF casualties also include American casualties in Pakistan, Uzbekistan, Guantanamo Bay (Cuba), Djibouti, Eritrea, Ethiopia, Jordan, Kenya, Kyrgyzstan, the Philippines, Seychelles, Sudan, Tajikistan, Turkey, and Yemen.
Date: February 29, 2012
Creator: Chesser, Susan G.
Object Type: Report
System: The UNT Digital Library
Afghanistan: Improvements Needed to Strengthen Management of U.S. Civilian Presence (open access)

Afghanistan: Improvements Needed to Strengthen Management of U.S. Civilian Presence

A letter report issued by the Government Accountability Office with an abstract that begins "U.S. agencies under Chief of Mission authority and the Department of Defense (DOD) have reported expanding their civilian presence in Afghanistan and took steps to improve their ability to track that presence. Since January 2009, U.S. agencies under Chief of Mission authority more than tripled their civilian presence from 320 to 1,142. However, although State could report total Chief of Mission numbers by agency, in mid-2011 GAO identified discrepancies in State’s data system used to capture more-detailed staffing information such as location and position type. State began taking steps in the fall of 2011 to improve the reliability of its data system. Also, DOD reported expanding its overall civilian presence from 394 civilians in January 2009 to 2,929 in December 2011 to help assist U.S. efforts in Afghanistan. The extent to which DOD’s data is reliable is unknown due to omissions and double counting, among other things. In a 2009 report, GAO noted similar data issues and recommended DOD improve data concerning deployed civilians. DOD concurred with the recommendation and expects the issues will be addressed by a new tracking system to be completed in fiscal …
Date: February 27, 2012
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Afghanistan: Politics, Elections, and Government Performance (open access)

Afghanistan: Politics, Elections, and Government Performance

This report discusses the current political state of Afghanistan, as well as the Afghan government. This report also discusses Afghanistan's relationship with the United States, particularly U.S. efforts to urge President Hamid Karzai, to address corruption within the Afghan government. The report also includes discussion of election fraud and corruption in Afghanistan.
Date: February 27, 2012
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Afghanistan: Post-Taliban Governance, Security, and U.S. Policy (open access)

Afghanistan: Post-Taliban Governance, Security, and U.S. Policy

This report discusses the current political state of Afghanistan, focusing particularly on the influence of the Taliban and other militant groups and on the leadership of Afghan President Hamid Karzai. This report also discusses the U.S.-Afghanistan relationship, in both the short and long term, and U.S. efforts under the Obama Administration to provide military, reconstructive, and stabilization aid.
Date: February 6, 2012
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Afghanistan Security: Department of Defense Effort to Train Afghan Police Relies on Contractor Personnel to Fill Skill and Resource Gaps (open access)

Afghanistan Security: Department of Defense Effort to Train Afghan Police Relies on Contractor Personnel to Fill Skill and Resource Gaps

Correspondence issued by the Government Accountability Office with an abstract that begins "U.S. government (USG), non-USG coalition, and DOD contractor personnel perform various roles in the ANP training program. These roles include: (1) serving as advisors and mentors to build ministerial capacity in areas such as financial and human resource management at the Afghan Ministry of Interior; (2) serving as mentors and trainers to develop Afghan commanders’ abilities to operate training sites and provide training to ANP recruits in areas such as criminal investigation, weapons, survival skills, and physical fitness; and (3) serving as embedded mentors to help deployed ANP units develop civilian policing skills. DOD contractor personnel also provide maintenance, logistics, and security support at training sites.As of November 2011, about 778 USG, non-USG coalition, and DOD contractor personnel provided ANP training and mentoring at 23 NATO-managed sites. Approximately 66 percent of these trainers and mentors were non-USG coalition personnel, 21 percent were USG personnel, and the remaining 13 percent were DOD contractor personnel. In addition, about 2,825 DOD contractor personnel provided maintenance, logistics, and security services at 12 NATO-managed training sites."
Date: February 23, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Air Conditioning with Magnetic Refrigeration (open access)

Air Conditioning with Magnetic Refrigeration

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Building Energy Efficiency Through Innovative Thermodevices (BEETIT) program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses air conditioning with magnetic refrigeration as part of "An Efficient, Green Compact Cooling System Using Magnetic Refrigeration" project.
Date: February 15, 2012
Creator: Astronautics Corporation of America
Object Type: Text
System: The UNT Digital Library
Air-Cooled Stack Freeze Tolerance Freeze Failure Modes and Freeze Tolerance Strategies for GenDriveTM Material Handling Application Systems and Stacks Final Scientific Report (open access)

Air-Cooled Stack Freeze Tolerance Freeze Failure Modes and Freeze Tolerance Strategies for GenDriveTM Material Handling Application Systems and Stacks Final Scientific Report

Air-cooled stack technology offers the potential for a simpler system architecture (versus liquid-cooled) for applications below 4 kilowatts. The combined cooling and cathode air allows for a reduction in part count and hence a lower cost solution. However, efficient heat rejection challenges escalate as power and ambient temperature increase. For applications in ambient temperatures below freezing, the air-cooled approach has additional challenges associated with not overcooling the fuel cell stack. The focus of this project was freeze tolerance while maintaining all other stack and system requirements. Through this project, Plug Power advanced the state of the art in technology for air-cooled PEM fuel cell stacks and related GenDrive material handling application fuel cell systems. This was accomplished through a collaborative work plan to improve freeze tolerance and mitigate freeze-thaw effect failure modes within innovative material handling equipment fuel cell systems designed for use in freezer forklift applications. Freeze tolerance remains an area where additional research and understanding can help fuel cells to become commercially viable. This project evaluated both stack level and system level solutions to improve fuel cell stack freeze tolerance. At this time, the most cost effective solutions are at the system level. The freeze mitigation strategies developed …
Date: February 14, 2012
Creator: Hancock, David, W.
Object Type: Report
System: The UNT Digital Library
Air Force and Interior Can Benefit from Additional Guidance When Deciding Whether to Lease or Purchase Equipment (open access)

Air Force and Interior Can Benefit from Additional Guidance When Deciding Whether to Lease or Purchase Equipment

Correspondence issued by the Government Accountability Office with an abstract that begins "Contracting officials from Air Force and Interior generally did not perform lease versus purchase analyses for selected contracts. Based on contract file reviews and discussions with contracting officials, we found that analyses were not performed and that contracting officials had not considered the alternative acquisition method for 24 of the 32 selected contracts. For the 8 contracts with lease versus purchase analyses, 5 were documented in the contract files and 3 were performed but were not documented, according to contracting officials. In most cases, contract files did not contain basic information to make lease or purchase decisions, such as the length of time the equipment would be used. Even files containing documentation of analyses generally did not address the full range of criteria specified in the FAR. For example, the analyses typically lacked a discussion of the financial and operating advantages of alternate approaches that would help contracting officials determine the appropriate acquisition method. Contracting officials noted that their decision to lease or purchase equipment often depends on the nature of the requirement, such as a short-term need for equipment, based on documents or other correspondence from the …
Date: February 7, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Air Traffic Control Modernization: Management Challenges Associated with Program Costs and Schedules Could Hinder NextGen Implementation (open access)

Air Traffic Control Modernization: Management Challenges Associated with Program Costs and Schedules Could Hinder NextGen Implementation

A letter report issued by the Government Accountability Office with an abstract that begins "In a review of 30 major ATC acquisition programs, all of which will contribute to the transition to NextGen, GAO found that costs for 11 of the 30 programs have increased from their initial estimates by a total of $4.2 billion and 15 programs experienced delays. The 11 acquisitions that experienced cost increases account for over 60 percent of FAA’s total acquisition costs ($11 billion of $17.7 billion) for the 30 programs. The 15 acquisitions that experienced schedule delays, of which 10 also had cost increases, ranged from 2 months to more than 14 years and averaged 48 months."
Date: February 16, 2012
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
All-Optical Time-Resolved Measurement of Laser Energy Modulation in a Relativistic Electron Beam (open access)

All-Optical Time-Resolved Measurement of Laser Energy Modulation in a Relativistic Electron Beam

Hamiltonian light-front theory has been proposed as a promising method for solving bound states problems in quantum field theory a long time ago, see, e.g., the review article[1] for its various advantages compared to the traditional instant-form theories. Recently the Basis Light-Front Quantization (BLFQ) approach [2, 3] has been developed as a nonperturbative approach to solve Hamiltonian light-front quantum field theory. Numerical efficiency is a key advantage of this approach. The basic idea of BLFQ is to represent the theory in an optimal basis which respects many symmetries of the theory and thus minimizes the dimensionality of the Hamiltonian for a fixed precision. Specifically, the BLFQ approach employs a plane wave basis in the light-front longitudinal direction and a 2D harmonic oscillator basis in the transverse directions. In previous work [3] this approach has been applied to evaluate the anomalous magnetic moment of electrons which are confined in an external trap with an extrapolation to the zero trap limit. In this work we extend and improve this approach in several aspects including the direct evaluation of a free electron system. This article is organized as follows: In Sec. 2 we discuss the key extensions and improvements made in this work …
Date: February 15, 2012
Creator: Xiang, D.; Colby, E.; Dunning, M.; Gilevich, S.; Hast, C.; Jobe, K. et al.
Object Type: Article
System: The UNT Digital Library
Alternative Energy for Higher Education (open access)

Alternative Energy for Higher Education

This project provides educational opportunities creating both a teaching facility and center for public outreach. The facility is the largest solar array in Nebraska. It was designed to allow students to experience a variety of technologies and provide the public with opportunities for exposure to the implementation of an alternative energy installation designed for an urban setting. The project integrates products from 5 panel manufacturers (including monocrystalline, polycrystalline and thin film technologies) mounted on both fixed and tracking structures. The facility uses both micro and high power inverters. The majority of the system was constructed to serve as an outdoor classroom where panels can be monitored, tested, removed and replaced by students. As an educational facility it primarily serves students in the Creighton University and Metropolitan Community College, but it also provides broader educational opportunities. The project includes a real-time “dashboard” and a historical database of the output of individual inverters and the corresponding meteorological data for researcher and student use. This allows the evaluation of both panel types and the feasibility of installation types in a region of the country subject to significant temperature, wind and precipitation variation.
Date: February 22, 2012
Creator: Michael Cherney, PhD
Object Type: Text
System: The UNT Digital Library
Alternative Methods of Flexible Base Compaction Acceptance (open access)

Alternative Methods of Flexible Base Compaction Acceptance

Partial abstract: "This report presents the results from the second year of research work investigating issues with flexible base acceptance testing within the Texas Department of Transportation (TxDOT).... Based on the findings, this report presents a modified construction specification for flesible base and a draft test procedure for using the [dynamic cone penetrometer (DCP)] for compaction acceptance."
Date: February 2012
Creator: Sebesta, Stephen; Shon, Chang-Seon & Scullion, Tom
Object Type: Report
System: The Portal to Texas History
ALTERNATIVES ANALYSIS FOR SELECTING ET #3 SITE (open access)

ALTERNATIVES ANALYSIS FOR SELECTING ET #3 SITE

Engineered trenches (ETs) are considered to be a cost-effective method for disposing Low Level Waste (LLW). Based on waste forecasts from waste generators, the last engineered trench in operation (ET No.2) is anticipated to close in FY14, requiring development of a new ET. Solid Waste requested that SRNL develop an assessment report that reviews four disposal options for this new ET (ET No.3) and determine which option would provide the 'best' Performance Assessment (PA) disposal limits for LLW (Appendix A). Those four options (see option footprint locations in Figure 1-1) are: (1) Disposal at grade on TRU Pads 7-13 where soil would be mounded over waste packages; (2) Excavation at a slightly modified SLIT No.13 location - near the Used Equipment Storage Area; (3) Excavation at a modified SLIT No.12 location - near the 643-26E Naval Reactor Component Disposal Area; and (4) Excavation east of TRU Pad No.26 that replaces northeast portions of four slit trench (ST) disposal units in the eastern set of STs. The assessment consisted of both quantitative and qualitative analyses. The quantitative analysis captured key aspects that were readily quantifiable and had predictable impacts on limits and doses. A simplified modeling strategy stemming from current Special …
Date: February 13, 2012
Creator: Collard, L. & Hamm, L.
Object Type: Report
System: The UNT Digital Library
ANALYSES AND COMPARISON OF BULK AND COIL SURFACE SAMPLES FROM THE DWPF SLURRY MIX EVAPORATOR (open access)

ANALYSES AND COMPARISON OF BULK AND COIL SURFACE SAMPLES FROM THE DWPF SLURRY MIX EVAPORATOR

Sludge samples from the DWPF Slurry Mix Evaporator (SME) heating coil frame and coil surface were characterized to identify differences that might help identify heat transfer fouling materials. The SME steam coils have seen increased fouling leading to lower boil-up rates. Samples of the sludge were taken from the coil frame somewhat distant from the coil (bulk tank material) and from the coil surface (coil surface sample). The results of the analysis indicate the composition of the two SME samples are very similar with the exception that the coil surface sample shows {approx}5-10X higher mercury concentration than the bulk tank sample. Elemental analyses and x-ray diffraction results did not indicate notable differences between the two samples. The ICP-MS and Cs-137 data indicate no significant differences in the radionuclide composition of the two SME samples. Semi-volatile organic analysis revealed numerous organic molecules, these likely result from antifoaming additives. The compositions of the two SME samples also match well with the analyzed composition of the SME batch with the exception of significantly higher silicon, lithium, and boron content in the batch sample indicating the coil samples are deficient in frit relative to the SME batch composition.
Date: February 17, 2012
Creator: Hay, M.; Nash, C. & Stone, M.
Object Type: Report
System: The UNT Digital Library
Analysis of 2011 Meteorological Data from the Knolls Atomic Power Laboratory and Kesselring Site Operations Facilities (open access)

Analysis of 2011 Meteorological Data from the Knolls Atomic Power Laboratory and Kesselring Site Operations Facilities

Both the Knolls Atomic Power Laboratory (KAPL) in Schenectady, NY and the Kesselring Site Operations (KSO) facility near Ballston Spa, NY are required to estimate the effects of hypothetical emissions of radiological material from their respective facilities by the US Environmental Protection Agency (EPA), which regulates these facilities. An atmospheric dispersion model known as CAP88, which was developed and approved by the EPA for such purposes, is used by KAPL and KSO to meet this requirement. CAP88 calculations over a given time period are based on statistical data on the meteorological conditions for that period. Both KAPL and KSO have on-site meteorological towers which take atmospheric measurements at a frequency ideal for EPA regulatory model input. However, an independent analysis and processing of the meteorological data from each tower is required to derive a data set appropriate for use in the CAP88 model. The National Atmospheric Release Advisory Center (NARAC) was contracted by KAPL to process the on-site data for the calendar year 2011. The purpose of this document is to: (1) summarize the procedures used in the preparation/analysis of the 2011 meteorological data; and (2) document adherence of these procedures to the guidance set forth in 'Meteorological Monitoring Guidance …
Date: February 27, 2012
Creator: Aluzzi, F J
Object Type: Report
System: The UNT Digital Library
Analysis of AGS E880 polarimeter data at Gy = 12.5. (open access)

Analysis of AGS E880 polarimeter data at Gy = 12.5.

Data were collected with the AGS internal (E880) polarimeter at G{gamma} = 12.5 during the FY04 polarized proton run. Measurements were made with forward scintillation counters in coincidence with recoil counter telescopes, permitting an absolute calibration of the polarimeter for both nylon and carbon targets. The results are summarized and they will also be useful for an absolute calibration of the AGS CNI polarimeter at G{gamma} = 12.5.
Date: February 23, 2012
Creator: Cadman, R.; Huang, H.; Krueger, K.; Spinka, H.; Underwood, D. (High Energy Physics) & Laboratory), (Brookhaven National
Object Type: Report
System: The UNT Digital Library
Analysis of Drought Impacts on Electricity Production in the Western and Texas Interconnections of the United States. (open access)

Analysis of Drought Impacts on Electricity Production in the Western and Texas Interconnections of the United States.

Electricity generation relies heavily on water resources and their availability. To examine the interdependence of energy and water in the electricity context, the impacts of a severe drought to assess the risk posed by drought to electricity generation within the western and Texas interconnections has been examined. The historical drought patterns in the western United States were analyzed, and the risk posed by drought to electricity generation within the region was evaluated. The results of this effort will be used to develop scenarios for medium- and long-term transmission modeling and planning efforts by the Western Electricity Coordination Council (WECC) and the Electric Reliability Council of Texas (ERCOT). The study was performed in response to a request developed by the Western Governors Association in conjunction with the transmission modeling teams at the participating interconnections. It is part of a U.S. Department of Energy-sponsored, national laboratory-led research effort to develop tools related to the interdependency of energy and water as part of a larger interconnection-wide transmission planning project funded under the American Recovery and Reinvestment Act. This study accomplished three main objectives. It provided a thorough literature review of recent studies of drought and the potential implications for electricity generation. It analyzed …
Date: February 9, 2012
Creator: Harto, C. B.; Yan, Y. E.; Demissie, Y. K.; Elcock, D.; Tidwell, V. C.; Hallett, K. et al.
Object Type: Report
System: The UNT Digital Library
ANALYSIS OF HARRELL MONOSODIUM TITANATE LOT #120111 (open access)

ANALYSIS OF HARRELL MONOSODIUM TITANATE LOT #120111

Monosodium titanate (MST) for use in the Actinide Removal Process (ARP) must be qualified and verified in advance. A single qualification sample for each batch of material is sent to SRNL for analysis, as well as a statistical sampling of verification samples. The Harrell Industries Lot No.120111 qualification and the first 12 verification samples met all the requirements in the specification indicating the material is acceptable for use in the process. Analyses of Pail 125 verification sample fails the criteria for solids content and has measurably lower pH, density, and total bottle weight. The verification sample for Pail 125 was retested for weight percent solids after checking that all of the solids had been suspended. The sample again failed to meet acceptance criteria. SRNL recommends accepting Pails 1 through 120. Pails 121 through 125 should be rejected and returned to the vendor.
Date: February 21, 2012
Creator: Shehee, T.
Object Type: Report
System: The UNT Digital Library
Analysis of Scalable Data-Privatization Threading Algorithms for Hybrid MPI/OpenMP Parallelization of Molecular Dynamics (open access)

Analysis of Scalable Data-Privatization Threading Algorithms for Hybrid MPI/OpenMP Parallelization of Molecular Dynamics

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Date: February 8, 2012
Creator: Kunaseth, M.; Richards, D. F.; Glosli, J. N.; Kalia, R. K.; Nakano, A. & Vashista, P.
Object Type: Article
System: The UNT Digital Library
Analytic approximate radiation effects due to Bremsstrahlung (open access)

Analytic approximate radiation effects due to Bremsstrahlung

The purpose of this note is to provide analytic approximate expressions that can provide quick estimates of the various effects of the Bremsstrahlung radiation produced relatively low energy electrons, such as the dumping of the beam into the beam stop at the ERL or field emission in superconducting cavities. The purpose of this work is not to replace a dependable calculation or, better yet, a measurement under real conditions, but to provide a quick but approximate estimate for guidance purposes only. These effects include dose to personnel, ozone generation in the air volume exposed to the radiation, hydrogen generation in the beam dump water cooling system and radiation damage to near-by magnets. These expressions can be used for other purposes, but one should note that the electron beam energy range is limited. In these calculations the good range is from about 0.5 MeV to 10 MeV. To help in the application of this note, calculations are presented as a worked out example for the beam dump of the R&D Energy Recovery Linac.
Date: February 1, 2012
Creator: Ben-Zvi, Ilan
Object Type: Report
System: The UNT Digital Library