PEP-X: An Ultimate Storage Ring Based on Fourth-Order Geometric Achromats (open access)

PEP-X: An Ultimate Storage Ring Based on Fourth-Order Geometric Achromats

We have designed an 'ultimate' storage ring for the PEP-X light source that achieves the diffraction limited emittances (at 1.5 {angstrom}) of 12 pm-rad in both horizontal and vertical planes with a 4.5-GeV beam. These emittances include the contribution of intrabeam scattering at a nominal current of 200 mA in 3300 bunches. This quality beam in conjunction with a conventional 4-m undulator in a straight section can generate synchrotron radiation having a spectral brightness above 10{sup 22} [photons/s/mm{sup 2}/mrad{sup 2}/0.1% BW] at a 10 keV photon energy. The high coherence at the diffraction limit makes PEP-X competitive with 4th generation light sources based on an energy recovery linac. In addition, the beam lifetime is several hours and the dynamic aperture is large enough to allow off-axis injection. The alignment and stability tolerances, though challenging, are achievable. A ring with all these properties is only possible because of several major advances in mitigating the effects of nonlinear resonances.
Date: April 6, 2012
Creator: Cai, Yunhai; Bane, Karl; Hettel, Robert; Nosochkov, Yuri & Wang, Min-Huey
Object Type: Article
System: The UNT Digital Library
The Senior Executive Service: Background and Options for Reform (open access)

The Senior Executive Service: Background and Options for Reform

Report that provides a history and background of the Senior Executive Service (SES), examines the central features of the SES, and discusses some areas in which advocates for SES reform have called for change.
Date: September 6, 2012
Creator: Carey, Maeve P.
Object Type: Report
System: The UNT Digital Library
Warm Bias and Parameterization of Boundary Upwelling in Ocean Models (open access)

Warm Bias and Parameterization of Boundary Upwelling in Ocean Models

It has been demonstrated that Eastern Boundary Currents (EBC) are a baroclinic intensification of the interior circulation of the ocean due to the emergence of mesoscale eddies in response to the sharp buoyancy gradients driven by the wind-stress and the thermal surface forcing. The eddies accomplish the heat and salt transport necessary to insure that the subsurface flow is adiabatic, compensating for the heat and salt transport effected by the mean currents. The EBC thus generated occurs on a cross-shore scale of order 20-100 km, and thus this scale needs to be resolved in climate models in order to capture the meridional transport by the EBC. Our result indicate that changes in the near shore currents on the oceanic eastern boundaries are linked not just to local forcing, such as coastal changes in the winds, but depend on the basin-wide circulation as well.
Date: November 6, 2012
Creator: Cessi, Paola & Wolfe, Christopher
Object Type: Report
System: The UNT Digital Library
Steady State Microbunching for High Brilliance and High Repetition Rate Storage Ring-Based Light Sources (open access)

Steady State Microbunching for High Brilliance and High Repetition Rate Storage Ring-Based Light Sources

Electron-based light sources have proven to be effective sources of high brilliance, high frequency radiation. Such sources are typically either linac-Free Electron Laser (FEL) or storage ring types. The linac-FEL type has high brilliance (because the beam is microbunched) but low repetition rate. The storage ring type has high repetition rate (rapid beam circulation) but comparatively low brilliance or coherence. We propose to explore the feasibility of a microbunched beam in a storage ring that promises high repetition rate and high brilliance. The steady-state-micro-bunch (SSMB) beam in storage ring could provide CW sources for THz, EUV, or soft X-rays. Several SSMB mechanisms have been suggested recently, and in this report, we review a number of these SSMB concepts as promising directions for high brilliance, high repetition rate light sources of the future. The trick of SSMB lies in the RF system, together with the associated synchrotron beam dynamics, of the storage ring. Considering various different RF arrangements, there could be considered a number of scenarios of the SSMB. In this report, we arrange these scenarios more or less in order of the envisioned degree of technical challenge to the RF system, and not in the chronological order of their original …
Date: September 6, 2012
Creator: Chao, Alex; Ratner, Daniel & Jiao, Yi
Object Type: Article
System: The UNT Digital Library
Determining mutant spectra of three RNA viral samples using ultra-deep sequencing (open access)

Determining mutant spectra of three RNA viral samples using ultra-deep sequencing

RNA viruses have extremely high mutation rates that enable the virus to adapt to new host environments and even jump from one species to another. As part of a viral transmission study, three viral samples collected from naturally infected animals were sequenced using Illumina paired-end technology at ultra-deep coverage. In order to determine the mutant spectra within the viral quasispecies, it is critical to understand the sequencing error rates and control for false positive calls of viral variants (point mutantations). I will estimate the sequencing error rate from two control sequences and characterize the mutant spectra in the natural samples with this error rate.
Date: June 6, 2012
Creator: Chen, H
Object Type: Report
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: September 6, 2012
Creator: Chesser, Susan G.
Object Type: Report
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). OEF actions took 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: December 6, 2012
Creator: Chesser, Susan G.
Object Type: Report
System: The UNT Digital Library
Managing Aging Effects on Dry Cask Storage Systems for Extended Long-Term Storage and Transportation of Used Fuel - Rev. 0 (open access)

Managing Aging Effects on Dry Cask Storage Systems for Extended Long-Term Storage and Transportation of Used Fuel - Rev. 0

The cancellation of the Yucca Mountain repository program in the United States raises the prospect of extended long-term storage (i.e., >120 years) and deferred transportation of used fuel at operating and decommissioned nuclear power plant sites. Under U.S. federal regulations contained in Title 10 of the Code of Federal Regulations (CFR) 72.42, the initial license term for an Independent Spent Fuel Storage Installation (ISFSI) must not exceed 40 years from the date of issuance. Licenses may be renewed by the U.S. Nuclear Regulatory Commission (NRC) at the expiration of the license term upon application by the licensee for a period not to exceed 40 years. Application for ISFSI license renewals must include the following: (1) Time-limited aging analyses (TLAAs) that demonstrate that structures, systems, and components (SSCs) important to safety will continue to perform their intended function for the requested period of extended operation; and (2) a description of the aging management program (AMP) for management of issues associated with aging that could adversely affect SSCs important to safety. In addition, the application must also include design bases information as documented in the most recent updated final safety analysis report as required by 10 CFR 72.70. Information contained in previous …
Date: July 6, 2012
Creator: Chopra, O. K.; Diercks, D.; Fabian, R.; Ma, D.; Shah, V.; Tam, S. W. et al.
Object Type: Report
System: The UNT Digital Library
Recess Appointments: A Legal Overview (open access)

Recess Appointments: A Legal Overview

This report provides an overview of the Recess Appointments Clause, exploring its historical application and legal interpretation by the executive branch, the courts, and the Comptroller General. Furthermore, congressional legislation designed to prevent the President's overuse or misuse of the Clause is also explored.
Date: January 6, 2012
Creator: Chu, Vivian S.
Object Type: Report
System: The UNT Digital Library
Hydraulic Fracturing: Technology, Impacts, and Policy (open access)

Hydraulic Fracturing: Technology, Impacts, and Policy

None
Date: November 6, 2012
Creator: Clark, C. E.; Burnham, A. J.; Harto, C. B. & Horner, R. M.
Object Type: Report
System: The UNT Digital Library
Right to Work Laws: Legislative Background and Empirical Research (open access)

Right to Work Laws: Legislative Background and Empirical Research

This report is divided into two parts. The first part discusses right to work (RTW) laws themselves. It provides a brief legislative history on the federal role in the regulation of unions, a summary of the origin and development of RTW laws, a discussion of recent events at the state level, and federal legislation related to RTW. The second part of the report reviews the varied empirical research on the effects of RTW laws. Specifically, it will discuss the mixed evidence indicating relationships between RTW laws and other economic outcomes.
Date: December 6, 2012
Creator: Collins, Benjamin
Object Type: Report
System: The UNT Digital Library
Comptroller Susan Combs Distributes $514 Million in Monthly Sales Tax Revenue to Local Governments (open access)

Comptroller Susan Combs Distributes $514 Million in Monthly Sales Tax Revenue to Local Governments

This document provides information on the distribution of $514 million in monthly sales tax revenue to local government.
Date: June 6, 2012
Creator: Combs, Susan
Object Type: Book
System: The Portal to Texas History
Impact Of Standing Water On Saltstone Placement II - Hydraulic Conductivity Data (open access)

Impact Of Standing Water On Saltstone Placement II - Hydraulic Conductivity Data

The amount of water present during placement and subsequent curing of saltstone has the potential to impact several properties important for grout quality. An active drain water system can remove residual standing water and expose the surface of the placed saltstone to air. Oxidation of the saltstone may result in an increase in the leachability of redox sensitive elements. A dry surface can lead to cracking, causing an increase in hydraulic conductivity. An inactive drain water system can allow standing water that generates unnecessary hydrostatic head on the vault walls. Standing water that cannot be removed via the drain system will be available for potential incorporation into subsequent grout placements. The objective of this work is to study the impact of standing water on grout quality pertaining to disposal units. A series of saltstone mixes was prepared and cured at ambient temperature to evaluate the impact of standing water on saltstone placement. The samples were managed to control drying effects on leachability by either exposing or capping the samples. The water to premix ratio was varied to represent a range of processing conditions. Samples were analyzed for density, leachability, and hydraulic conductivity. Report SRNL-STI-2012-00546 was issued detailing the experimental procedure, …
Date: December 6, 2012
Creator: Cozzi, A. D. & Pickenheim, B. R.
Object Type: Report
System: The UNT Digital Library
Congressional Liaison Offices of Selected Federal Agencies (open access)

Congressional Liaison Offices of Selected Federal Agencies

Report that offer a list of 200 congressional liaison offices.
Date: September 6, 2012
Creator: Crane-Hirsch, Audrey C.
Object Type: Report
System: The UNT Digital Library
Summary Report of the Consultants Meeting on Further Development of EXFOR (open access)

Summary Report of the Consultants Meeting on Further Development of EXFOR

N/A
Date: March 6, 2012
Creator: D., Brown
Object Type: Report
System: The UNT Digital Library
In Brief: Next Steps in the War in Afghanistan? Issues for Congress (open access)

In Brief: Next Steps in the War in Afghanistan? Issues for Congress

This report considers issues that may be of interest to Congress as it considers the strength and duration of further U.S. involvement in Afghanistan, to 2014 and beyond.
Date: December 6, 2012
Creator: Dale, Catherine
Object Type: Report
System: The UNT Digital Library
"Surge Recovery" and Next Steps in the War in Afghanistan: In Brief (open access)

"Surge Recovery" and Next Steps in the War in Afghanistan: In Brief

This report draws in part on the author's recent three-week visit to Afghanistan, in November 2011, based on an invitation from the Commander of NATO's International Security Assistance Force (ISAF), General John Allen. It provides initial observations about surge recovery in broader operational and strategic context, and links those observations to current debates that may be of interest to Congress as it considers the strength and duration of further U.S. involvement in Afghanistan.
Date: January 6, 2012
Creator: Dale, Catherine
Object Type: Report
System: The UNT Digital Library
LITERATURE REVIEW OF PUO2 CALCINATION TIME AND TEMPERATURE DATA FOR SPECIFIC SURFACE AREA (open access)

LITERATURE REVIEW OF PUO2 CALCINATION TIME AND TEMPERATURE DATA FOR SPECIFIC SURFACE AREA

The literature has been reviewed in December 2011 for calcination data of plutonium oxide (PuO{sub 2}) from plutonium oxalate Pu(C{sub 2}O{sub 4}){sub 2} precipitation with respect to the PuO{sub 2} specific surface area (SSA). A summary of the literature is presented for what are believed to be the dominant factors influencing SSA, the calcination temperature and time. The PuO{sub 2} from Pu(C{sub 2}O{sub 4}){sub 2} calcination data from this review has been regressed to better understand the influence of calcination temperature and time on SSA. Based on this literature review data set, calcination temperature has a bigger impact on SSA versus time. However, there is still some variance in this data set that may be reflecting differences in the plutonium oxalate preparation or different calcination techniques. It is evident from this review that additional calcination temperature and time data for PuO{sub 2} from Pu(C{sub 2}O{sub 4}){sub 2} needs to be collected and evaluated to better define the relationship. The existing data set has a lot of calcination times that are about 2 hours and therefore may be underestimating the impact of heating time on SSA. SRNL recommends that more calcination temperature and time data for PuO{sub 2} from Pu(C{sub 2}O{sub …
Date: March 6, 2012
Creator: Daniel, G.
Object Type: Report
System: The UNT Digital Library
Biomass Gas Cleanup Using a Therminator (open access)

Biomass Gas Cleanup Using a Therminator

The objective of the project is to develop and demonstrate a novel fluidized-bed process module called a “Therminator” to simultaneously destroy and/or remove tar, NH3 and H2S from raw syngas produced by a fluidized-bed biomass gasifier. The raw syngas contains as much as 10 g/m3 of tar, 4,000 ppmv of NH3 and 100 ppmv of H2S. The goal of the Therminator module would be to use promising regenerable catalysts developed for removing tar, ammonia, and H2S down to low levels (around 10 ppm). Tars are cracked to a non-condensable gas and coke that would deposit on the acid catalyst. We will deposit coke, much like a fluid catalytic cracker (FCC) in a petroleum refinery. The deposited coke fouls the catalyst, much like FCC, but the coke would be burned off in the regenerator and the regenerated catalyst would be returned to the cracker. The rapid circulation between the cracker and regenerator would ensure the availability of the required amount of regenerated catalyst to accomplish our goal. Also, by removing sulfur down to less than 10 ppmv, NH3 decomposition would also be possible in the cracker at 600-700°C. In the cracker, tar decomposes and lays down coke on the acid sites …
Date: March 6, 2012
Creator: Dayton, David C.; Kataria, Atish & Gupta, Rabhubir
Object Type: Report
System: The UNT Digital Library
Identifying Longitudinal Jitter Sources in the LCLS Linac (open access)

Identifying Longitudinal Jitter Sources in the LCLS Linac

The Linac Coherent Light Source (LCLS) at SLAC is an x-ray Free Electron Laser (FEL) with wavelengths of 0.15 nm to 1.5 nm. The electron beam stability is important for good lasing. While the transverse jitter of the beam is about 10-20% of the rms beam sizes, the jitter in the longitudinal phase space is a multiple of the energy spread and bunch length. At the lower energy of 4.3 GeV (corresponding to the longest wavelength of 1.5 nm) the relative energy jitter can be 0.125%, while the rms energy spread is with 0.025% five times smaller. An even bigger ratio exists for the arrival time jitter of 50 fs and the bunch duration of about 5 fs (rms) in the low charge (20 pC) operating mode. Although the impact to the experiments is reduced by providing pulse-by-pulse data of the measured energy and arrival time, it would be nice to understand and mitigate the root causes of this jitter. The thyratron of the high power supply of the RF klystrons is one of the main contributors. Another suspect is the multi-pacting in the RF loads. Phase measurements down to 0.01 degree (equals 10 fs) along the RF pulse were …
Date: July 6, 2012
Creator: Decker, Franz-Josef; Akre, Ron; Brachmann, Axel; Craft, Jim; Ding, Yuantao; Dowell, David et al.
Object Type: Article
System: The UNT Digital Library
Small Business Size Standards: A Historical Analysis of Contemporary Issues (open access)

Small Business Size Standards: A Historical Analysis of Contemporary Issues

This report provides a historical examination of the SBA's size standards, assesses competing views concerning how to define a small business, and discusses how the Small Business Jobs Act of 2010 might affect program eligibility. It also discusses H.R. 585, the Small Business Size Standard Flexibility Act of 2011, which would authorize the SBA's Office of Chief Counsel for Advocacy to approve or disapprove a size standard proposed by a federal agency if it deviates from the SBA's size standards.
Date: December 6, 2012
Creator: Dilger, Robert J.
Object Type: Report
System: The UNT Digital Library
Unfunded Mandates Reform Act: History, Impact, and Issues (open access)

Unfunded Mandates Reform Act: History, Impact, and Issues

This report examines debates over what constitutes an unfunded federal mandate and the Unfunded Mandates Reform Act of 1995 (UMRA's) implementation. It focuses on UMRA's requirement that the Congressional Budget Office (CBO) issue written cost estimate statements for federal mandates in legislation, its procedures for raising points of order in the House and Senate concerning unfunded federal mandates in legislation, and its requirement that federal agencies prepare written cost estimate statements for federal mandates in rules.
Date: December 6, 2012
Creator: Dilger, Robert Jay & Beth, Richard S.
Object Type: Report
System: The UNT Digital Library
Absolute Determination of Charge-Coupled Device Quantum Detection Efficiency Using Si K-Edge X-Ray Absorption Fine Structure (open access)

Absolute Determination of Charge-Coupled Device Quantum Detection Efficiency Using Si K-Edge X-Ray Absorption Fine Structure

We report a method to determine the quantum detection efficiency and the absorbing layers on a front-illuminated charge-coupled device (CCD). The CCD under study, as part of a crystal spectrometer, measures intense continuum x-ray emission from a picosecond laser-produced plasma and spectrally resolves the Si K-edge x-ray absorption fine structure features due to the electrode gate structure of the device. The CCD response across the Si K-edge shows a large discontinuity as well as a number of oscillations that are identified individually and uniquely from Si, SiO{sub 2}, and Si{sub 3}N{sub 4} layers. From the spectral analysis of the structure and K-edge discontinuity, the active layer thickness and the different absorbing layers thickness can be determined precisely. A precise CCD detection model from 0.2-10 keV can be deduced from this highly sensitive technique.
Date: May 6, 2012
Creator: Dunn, J. & Steel, A. B.
Object Type: Article
System: The UNT Digital Library
Thermal Regime of a Cold Air Trap in Central Pennsylvania, USA: the Trough Creek Ice Mine (open access)

Thermal Regime of a Cold Air Trap in Central Pennsylvania, USA: the Trough Creek Ice Mine

Air temperatures internal and external to a talus cave (‘ice mine’) in central Pennsylvania were measured hourly for three years. Despite its location near the base of a talus slope, the cave demonstrated the thermal characteristics of an apparently static cave, with limited connections to the external environment other than through the cave entrance. Congelation ice that lasted until late spring formed as drip or flowstone and ponded ice from the limited influx of infiltrating water during late winter/early spring. A closed period of thermal stratification and slow warming of cave air was followed by an open period in winter months during which the cave was cooled by the influx of cold dry air. Unlike the occasionally strong and localised cooling induced by the flow of cold air from vents at the base of talus slopes, static cold traps retain their cold air and have little apparent effect on surrounding biota, instead providing potential refugia for organisms that prefer colder temperatures. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.
Date: August 6, 2012
Creator: Edenborn, Harry M.; Sams, James I. & Kite, Steven
Object Type: Report
System: The UNT Digital Library