Reversible Electron Beam Heating for Suppression of Micro bunching Instabilities at Free-Electron Lasers (open access)

Reversible Electron Beam Heating for Suppression of Micro bunching Instabilities at Free-Electron Lasers

The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversible electron beam heating system based on two transverse deflecting radio-frequency structures (TDSs) upstream and downstream of a magnetic bunch compressor chicane. The additional energy spread is introduced in the first TDS, which suppresses the microbunching instability, and then is eliminated in the second TDS. We show the feasibility of the microbunching gain suppression based on calculations and simulations including the effects of coherent synchrotron radiation. Acceptable electron beam and radio-frequency jitter are identified, and inherent options for diagnostics and on-line monitoring of the electron beam's longitudinal phase space are discussed.
Date: May 30, 2012
Creator: Behrens, Christopher; Huang, Zhirong & Xiang, Dao
Object Type: Article
System: The UNT Digital Library
Impact Of Melter Internal Design On Off-Gas Flammability (open access)

Impact Of Melter Internal Design On Off-Gas Flammability

The purpose of this study was to: (1) identify the more dominant design parameters that can serve as the quantitative measure of how prototypic a given melter is, (2) run the existing DWPF models to simulate the data collected using both DWPF and non-DWPF melter configurations, (3) confirm the validity of the selected design parameters by determining if the agreement between the model predictions and data is reasonably good in light of the design and operating conditions employed in each data set, and (4) run Computational Fluid Dynamics (CFD) simulations to gain new insights into how fluid mixing is affected by the configuration of melter internals and to further apply the new insights to explaining, for example, why the agreement is not good.
Date: May 30, 2012
Creator: Choi, A. S. & Lee, S. Y.
Object Type: Report
System: The UNT Digital Library
EU-U.S. Economic Ties: Framework, Scope, and Magnitude (open access)

EU-U.S. Economic Ties: Framework, Scope, and Magnitude

This report provides background information and analysis of the U.S.-EU economic relationship for members of the 112th Congress as they contemplate the costs and benefits of closer U.S. economic ties with the EU. It examines the economic and political framework of the relationship and the scope and magnitude of the ties based on data from various sources. In addition, the report analyzes the implications these factors have for U.S. economic policy toward the EU.
Date: May 30, 2012
Creator: Cooper, William H.
Object Type: Report
System: The UNT Digital Library
Water Quality Issues in the 112th Congress: Oversight and Implementation (open access)

Water Quality Issues in the 112th Congress: Oversight and Implementation

None
Date: May 30, 2012
Creator: Copeland, Claudia
Object Type: Report
System: The UNT Digital Library
Water Quality Issues in the 112th Congress: Oversight and Implementation (open access)

Water Quality Issues in the 112th Congress: Oversight and Implementation

This report discusses water quality legislation. A number of Clean Water Act issues have been the subject of congressional oversight and legislation, including the environmental and economic impacts of Chesapeake Bay restoration efforts, federal promulgation of water quality standards in Florida, regulation of surface coal mining activities in Appalachia, and other CWA regulatory actions. Congressional interest in several of these issues has been reflected in debate over policy provisions of legislation providing FY2012 appropriations for EPA (P.L. 112-74).
Date: May 30, 2012
Creator: Copeland, Claudia
Object Type: Report
System: The UNT Digital Library
DESTRUCTIVE EXAMINATION OF SHIPPING PACKAGE 9975-03431 (open access)

DESTRUCTIVE EXAMINATION OF SHIPPING PACKAGE 9975-03431

Destructive and non-destructive examinations have been performed on specified components of shipping package 9975-03431. For those attributes that were also measured during the field surveillance, no significant changes were observed. All observations and test results met identified criteria, or were collected for information and trending purposes. Except for modest corrosion of the lead shield (which is typical of these packages following several years service), no evidence of a degraded condition was found in this package. The Savannah River Site (SRS) stores packages containing plutonium (Pu) materials in the KArea Complex (KAC). The Pu materials are packaged per the DOE 3013 Standard and stored within Model 9975 shipping packages in KAC. The KAC facility DSA (Document Safety Analysis) credits the Model 9975 package to perform several safety functions, including criticality prevention, impact resistance, containment, and fire resistance to ensure the plutonium materials remain in a safe configuration during normal and accident conditions. The Model 9975 package is expected to perform its safety function for at least 12 years from initial packaging. The DSA recognizes the degradation potential for the materials of package construction over time in the KAC storage environment and requires an assessment of materials performance to validate the assumptions …
Date: May 30, 2012
Creator: Daugherty, W.
Object Type: Report
System: The UNT Digital Library
The Temporary Assistance for Needy Families Block Grant: An Introduction (open access)

The Temporary Assistance for Needy Families Block Grant: An Introduction

None
Date: May 30, 2012
Creator: Falk, Gene
Object Type: Report
System: The UNT Digital Library
TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR (open access)

TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR

Experimental results are reported for test beam acceleration and deflection in a two-channel, cm-scale, rectangular dielectric-lined wakefield accelerator structure energized by a 14-MeV drive beam. The dominant waveguide mode of the structure is at {approx}30 GHz, and the structure is configured to exhibit a high transformer ratio ({approx}12:1). Accelerated bunches in the narrow secondary channel of the structure are continuously energized via Cherenkov radiation that is emitted by a drive bunch moving in the wider primary channel. Observed energy gains and losses, transverse deflections, and changes in the test bunch charge distribution compare favorably with predictions of theory.
Date: May 30, 2012
Creator: Hirshfield, Jay L.
Object Type: Report
System: The UNT Digital Library
Second Line of Defense, Megaports Initiative, Operational Testing and Evaluation Plan, Port of Lazaro Cardenas, Mexico (open access)

Second Line of Defense, Megaports Initiative, Operational Testing and Evaluation Plan, Port of Lazaro Cardenas, Mexico

The purpose of the Operational Testing and Evaluation (OT&E) phases of the project is to prepare for turnover of the Megaports System supplied by U.S. Department of Energy/National Nuclear Security Administration (DOE/NNSA)—located at the Export Lanes of the Port of Lazaro Cardenas, Mexico—to the Government of Mexico (GOM).
Date: May 30, 2012
Creator: Hughes, Jamie D.
Object Type: Report
System: The UNT Digital Library
Enhanced Generic Phase-field Model of Irradiation Materials: Fission Gas Bubble Growth Kinetics in Polycrystalline UO2 (open access)

Enhanced Generic Phase-field Model of Irradiation Materials: Fission Gas Bubble Growth Kinetics in Polycrystalline UO2

Experiments show that inter-granular and intra-granular gas bubbles have different growth kinetics which results in heterogeneous gas bubble microstructures in irradiated nuclear fuels. A science-based model predicting the heterogeneous microstructure evolution kinetics is desired, which enables one to study the effect of thermodynamic and kinetic properties of the system on gas bubble microstructure evolution kinetics and morphology, improve the understanding of the formation mechanisms of heterogeneous gas bubble microstructure, and provide the microstructure to macroscale approaches to study their impact on thermo-mechanical properties such as thermo-conductivity, gas release, volume swelling, and cracking. In our previous report 'Mesoscale Benchmark Demonstration, Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing', we developed a phase-field model to simulate the intra-granular gas bubble evolution in a single crystal during post-irradiation thermal annealing. In this work, we enhanced the model by incorporating thermodynamic and kinetic properties at grain boundaries, which can be obtained from atomistic simulations, to simulate fission gas bubble growth kinetics in polycrystalline UO2 fuels. The model takes into account of gas atom and vacancy diffusion, vacancy trapping and emission at defects, gas atom absorption and resolution at gas bubbles, internal pressure in gas bubbles, elastic interaction …
Date: May 30, 2012
Creator: Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert O.; Gao, Fei & Sun, Xin
Object Type: Report
System: The UNT Digital Library
Extension of the Bayesloc Multiple-Event Location Algorithm to Include Differential Travel Time Measurements (open access)

Extension of the Bayesloc Multiple-Event Location Algorithm to Include Differential Travel Time Measurements

None
Date: May 30, 2012
Creator: Myers, S C & Johannesson, G
Object Type: Article
System: The UNT Digital Library
Veterans' Medical Care: FY2013 Appropriations (open access)

Veterans' Medical Care: FY2013 Appropriations

This report focuses on the Veterans Health Administration (VHA). The VHA is primarily a direct service provider of primary care, specialized care, and related medical and social support services to veterans through the nation's largest integrated health care system.
Date: May 30, 2012
Creator: Panangala, Sidath Viranga
Object Type: Report
System: The UNT Digital Library
U.S. Solar Photovoltaic Manufacturing: Industry Trends, Global Competition, Federal Support (open access)

U.S. Solar Photovoltaic Manufacturing: Industry Trends, Global Competition, Federal Support

The most widely used solar technology involves photovoltaic (PV) solar modules, which draw on semiconducting materials to convert sunlight into electricity. By year-end 2011, the total number of grid-connected PV systems nationwide reached almost 215,000. Domestic demand is met both by imports and by about 100 U.S. manufacturing facilities. The competitiveness of solar PV as a source of electric generation in the United States will likely be adversely affected both by the expiration of tax provisions and by the rapid development of shale gas, which has the potential to lower the cost of gas-fired power generation and reduce the cost-competitiveness of solar power, particularly as an energy source for utilities. In light of these developments, the ability to build a significant U.S. production base for PV equipment is in question.
Date: May 30, 2012
Creator: Platzer, Michaela D.
Object Type: Report
System: The UNT Digital Library
Science and Technology Review, July/August 2012 (open access)

Science and Technology Review, July/August 2012

This month's issue has the following articles: (1) Energetic Materials Research Finds an Enduring Home and Mission - Commentary by Bruce T. Goodwin; (2) A Home for Energetic Materials and Their Experts - The Energetic Materials Center has become the National Nuclear Security Administration's go-to facility for high explosives formulation, testing, and expertise; (3) A Spectra-Tacular Sight - Scientists use spectrographic techniques and a high-powered telescope to study the atmospheric composition of exoplanets; (4) Seismic Data Pinpoint Fractures for Geothermal Energy - Livermore researchers are developing advanced microseismic analysis techniques to understand what happens beneath Earth's surface, where hot rock can provide an energy source; and (5) Employees Keep Up with the Times - The Laboratory's Education Assistance Program helps its workforce stay productive, skilled, and dynamic.
Date: May 30, 2012
Creator: Poyneer, L A
Object Type: Report
System: The UNT Digital Library
Texas Attorney General Opinion: GA-0942 (open access)

Texas Attorney General Opinion: GA-0942

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Authority of Type A general-law municipality with a population of less than 900,000 to enact an ordinance setting either a 300-foot "Alcohol-Free School Zone" or a 1,000-foot zone around a school in which the sale of of alcoholic beverages for off-premises consumption would be prohibited (RQ-1028-GA)
Date: May 30, 2012
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: GA-0943 (open access)

Texas Attorney General Opinion: GA-0943

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Whether, in determining the market value of a residence homestead, a chief appraiser is required to consider the value of previously sold foreclosed residential property (RQ-1029-GA)
Date: May 30, 2012
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: GA-0944 (open access)

Texas Attorney General Opinion: GA-0944

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Whether a mental health professional is required by chapter 261, Family Code, to report abuse or neglect that occurred during the childhood of a now-adult patient (RQ-1030-GA)
Date: May 30, 2012
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Texas Attorney General Opinion: GA-0945 (open access)

Texas Attorney General Opinion: GA-0945

Document issued by the Office of the Attorney General of Texas in Austin, Texas, providing an interpretation of Texas law. It provides the opinion of the Texas Attorney General, Greg Abbott, regarding a legal question submitted for clarification; Whether the Angleton-Danbury Hospital District is authorized to sell a hospital facility to a third party and lease care for the District's needy residents (RQ-1033-GA)
Date: May 30, 2012
Creator: Texas. Attorney-General's Office.
Object Type: Text
System: The Portal to Texas History
Waste Heat to Power Systems (open access)

Waste Heat to Power Systems

This publication offers information on the waste heat to power (WHP). The WHP is the process of capturing heat discarded by an existing industrial process by using heat to generate energy.
Date: May 30, 2012
Creator: United States. Environmental Protection Agency. Combined Heat and Power Partnership.
Object Type: Text
System: The UNT Digital Library
GAO Schedule Assessment Guide: Best Practices for Project Schedules—Exposure Draft (open access)

GAO Schedule Assessment Guide: Best Practices for Project Schedules—Exposure Draft

Guidance issued by the Government Accountability Office with an abstract that begins "The U.S. Government Accountability Office is responsible for, among other things, assisting the Congress in its oversight of the federal government, including agencies’ stewardship of public funds. To use public funds effectively, the government must meet the demands of today’s changing world by employing effective management practices and processes, including the measurement of government program performance. In addition, legislators, government officials, and the public want to know whether government programs are achieving their goals and what their costs are."
Date: May 30, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Oil Dispersants: Additional Research Needed, Particularly on Subsurface and Arctic Applications (open access)

Oil Dispersants: Additional Research Needed, Particularly on Subsurface and Arctic Applications

A letter report issued by the Government Accountability Office with an abstract that begins "According to experts, agency officials, and specialists, much is known about the use of chemical dispersants on the surface of the water, but gaps remain in several research areas. For example, experts generally agreed that there is a basic understanding of the processes that influence where and how oil travels through the water, but that more research was needed to quantify the actual rate at which dispersants biodegrade. In addition, all the experts GAO spoke with said that little is known about the application and effects of dispersants applied subsurface, noting that specific environmental conditions, such as higher pressures, may influence dispersants’ effectiveness. Knowledge about the use and effectiveness of dispersants in the Arctic is also limited, with less research conducted on dispersant use there than in temperate or tropical climates. For example, one expert noted that more research is needed on biodegradation rates for oil in the Arctic because the cold temperature may slow the process down."
Date: May 30, 2012
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Securities Regulation: Opportunities Exist to Improve SEC's Oversight of the Financial Industry Regulatory Authority (open access)

Securities Regulation: Opportunities Exist to Improve SEC's Oversight of the Financial Industry Regulatory Authority

A letter report issued by the Government Accountability Office with an abstract that begins "Historically, the Securities and Exchange Commission’s (SEC) oversight of the Financial Industry Regulatory Authority’s (FINRA) programs and operations varied, with some programs and operations receiving regular oversight and others receiving limited or no oversight. Through its inspection process, SEC conducted routine and special inspections of various aspects of FINRA regulatory programs, including examinations, surveillance, and enforcement programs. SEC has also conducted routine inspections of FINRA’s advertising and arbitration programs but not as frequently as it had planned. SEC has also regularly reviewed FINRA proposed rule changes that are subject to SEC approval to determine consistency with the Securities Exchange Act of 1934 and related rules and regulations. However, neither SEC nor FINRA conducts retrospective reviews of FINRA’s rules. GAO and others have reported on the usefulness of retrospective reviews as they allow agencies to assess the effectiveness of their rules, and some federal financial regulators, including SEC, have begun pursuing plans to conduct retrospective reviews of their rules in light of a recent executive order that encourages independent regulatory agencies to do so. By not conducting these reviews, FINRA may be missing an opportunity to systematically …
Date: May 30, 2012
Creator: United States. Government Accountability Office.
Object Type: Report
System: The UNT Digital Library
Tribal Law and Order Act: None of the Surveyed Tribes Reported Exercising the New Sentencing Authority, and the Department of Justice Could Clarify Tribal Eligibility for Certain Grant Funds (open access)

Tribal Law and Order Act: None of the Surveyed Tribes Reported Exercising the New Sentencing Authority, and the Department of Justice Could Clarify Tribal Eligibility for Certain Grant Funds

Correspondence issued by the Government Accountability Office with an abstract that begins "Among the tribes that responded to our survey (109), none reported that they were exercising TLOA’s new sentencing authority, and, in open-ended responses, many tribes (86 of 90, or 96 percent) reported challenges to exercising this authority due to funding limitations. Tribes were relatively evenly split among those that reported that they have plans to exercise the new authority (36 of 101, or 36 percent); that they did not know the tribe’s plans to exercise the new authority (34 of 101, or 34 percent) because, for instance, the tribal council has not yet made a decision; and that they did not have plans to do so (31 of 101, or 31 percent). In addition, 64 percent of selected tribes (70 of 109) reported implementing at least half of the requirements necessary for exercising the new sentencing authority, but reported challenges in implementing other requirements. Specifically, these tribes most frequently reported implementing the requirement to maintain a record of the criminal proceeding, and least frequently reported providing the defendant a licensed defense attorney. For example, 8 tribes that described challenges to exercising the new sentencing authority reported challenges with …
Date: May 30, 2012
Creator: United States. Government Accountability Office.
Object Type: Text
System: The UNT Digital Library
Beam Ion Instability in ILC Damping Ring with Multi-Gas Species (open access)

Beam Ion Instability in ILC Damping Ring with Multi-Gas Species

Ion induced beam instability is one critical issue for the electron damping ring of the International Linear Collider (ILC) due to its ultra small emittance of 2 pm. The beam ion instability with various beam filling patterns for the latest lattice DTC02 is studied using PIC code. The code has been benchmarked with SPEAR3 experimental data and there is a good agreement between the simulation and observations. It uses the optics from MAD and can handle arbitrary beam filling pattern and vacuum. Different from previous studies, multi-gas species and exact beam filling patterns have been modeled simultaneously in the study. This feature makes the study more realistic. Analyses have been done to compare with the simulations.
Date: May 30, 2012
Creator: Wang, Lanfa & Pivi, Mauro
Object Type: Article
System: The UNT Digital Library