Language

201 MHz Cavity R&D for MUCOOL and MICE (open access)

201 MHz Cavity R&D for MUCOOL and MICE

We describe the design, fabrication, analysis and preliminary testing of the prototype 201 MHz copper cavity for a muon ionization cooling channel. Cavity applications include the Muon Ionization Cooling Experiment (MICE) as well as cooling channels for a neutrino factory or a muon collider. This cavity was developed by the US muon cooling (MUCOOL) collaboration and is being tested in the MUCOOL Test Area (MTA) at Fermilab. To achieve a high accelerating gradient, the cavity beam irises are terminated by a pair of curved, thin beryllium windows. Several fabrication methods developed for the cavity and windows are novel and offer significant cost savings as compared to conventional construction methods. The cavity's thermal and structural performances are simulated with an FEA model. Preliminary high power RF commissioning results will be presented.
Date: June 23, 2006
Creator: Li, Derun; Virostek, Steve; Zisman, Michael; Norem, Jim; Bross,Alan; Moretti, Alfred et al.
Object Type: Article
System: The UNT Digital Library
Accurate labeling of the light-actinide O4,5 ionization edges (open access)

Accurate labeling of the light-actinide O4,5 ionization edges

In this short article the accurate labeling of the O4,5 edges of the light actinides is addressed. The O4 and O5 edges are both contained in what is termed the ''giant resonance'' and the smaller ''pre-peak'' that is observed is a consequence of first-order perturbation by the 5d spin-orbit interaction. Thus, the small prepeak in the actinide 5d {yields} 5f transition should not be labeled the O5 peak, but rather the {Delta}S=1 peak.
Date: August 23, 2006
Creator: Moore, K & der Laan, G v
Object Type: Article
System: The UNT Digital Library
Adapting Existing Spatial Data Sets to New Uses: An Example from Energy Modeling (open access)

Adapting Existing Spatial Data Sets to New Uses: An Example from Energy Modeling

Energy modeling and analysis often relies on data collected for other purposes such as census counts, atmospheric and air quality observations, and economic projections. These data are available at various spatial and temporal scales, which may be different from those needed by the energy modeling community. If the translation from the original format to the format required by the energy researcher is incorrect, then resulting models can produce misleading conclusions. This is of increasing importance, because of the fine resolution data required by models for new alternative energy sources such as wind and distributed generation. This paper addresses the matter by applying spatial statistical techniques which improve the usefulness of spatial data sets (maps) that do not initially meet the spatial and/or temporal requirements of energy models. In particular, we focus on (1) aggregation and disaggregation of spatial data, (2) imputing missing data and (3) merging spatial data sets.
Date: June 23, 2006
Creator: Johanesson, G; Stewart, J S; Barr, C; Sabeff, L B; George, R; Heimiller, D et al.
Object Type: Article
System: The UNT Digital Library
Aerosol sample preparation methods for X-ray diffractive imaging: Size-selected spherical nanoparticles on silicon nitride foils (open access)

Aerosol sample preparation methods for X-ray diffractive imaging: Size-selected spherical nanoparticles on silicon nitride foils

None
Date: October 23, 2006
Creator: Bogan, M. J.; Benner, W. H.; Hau-Riege, S.; Chapman, H. & Frank, M.
Object Type: Article
System: The UNT Digital Library
Afghanistan: Post-War Governance, Security, and U.S. Policy (open access)

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

Afghanistan's political transition was completed with the convening of a parliament in December 2005, but since then insurgent threats to Afghanistan's government have escalated to the point that some experts are questioning the future of U.S. stabilization efforts. Afghan citizens are enjoying new personal freedoms that were forbidden under the Taliban. Women are participating in economic and political life. U.S. stabilization measures focus on strengthening the central government and its security forces and on promoting reconstructing while combating the renewed insurgent challenge.
Date: August 23, 2006
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Afghanistan: Post-War Governance, Security, and U.S. Policy (open access)

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

The United States and its allies are helping Afghanistan emerging from more than 22 years of warfare, although substantial risk to Afghan stability remains. Before the U.S. military campaign against the orthodox Islamist Taliban movement began on October 7, 2001, Afghanistan had been mired in conflict since the Soviet invasion of Afghanistan in 1979. The defeat of the Taliban has enabled the United States and its coalition partners to send forces throughout Afghanistan to search for Taliban and Al Qaeda fighters and leaders that remain at large, including Osama bin Laden. As the war against remaining Al Qaeda and Taliban elements winds down, the United States is shifting its military focus toward stabilizing the interim government, including training a new Afghan national army, and supporting the international security force (ISAF) that is helping the new government provide security.
Date: August 23, 2006
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Afghanistan: Post-War Governance, Security, and U.S. Policy (open access)

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

The United States and its allies are helping Afghanistan emerging from more than 22 years of warfare, although substantial risk to Afghan stability remains. Before the U.S. military campaign against the orthodox Islamist Taliban movement began on October 7, 2001, Afghanistan had been mired in conflict since the Soviet invasion of Afghanistan in 1979. The defeat of the Taliban has enabled the United States and its coalition partners to send forces throughout Afghanistan to search for Taliban and Al Qaeda fighters and leaders that remain at large, including Osama bin Laden. As the war against remaining Al Qaeda and Taliban elements winds down, the United States is shifting its military focus toward stabilizing the interim government, including training a new Afghan national army, and supporting the international security force (ISAF) that is helping the new government provide security.
Date: August 23, 2006
Creator: Katzman, Kenneth
Object Type: Report
System: The UNT Digital Library
Agricultural Export and Food Aid Programs (open access)

Agricultural Export and Food Aid Programs

This report discusses projected agricultural imports and exports for FY2006, as well as legislation that deals with federal programs in support of agricultural exports and federal aid dedicated to farms and agricultural reform.
Date: January 23, 2006
Creator: Hanrahan, Charles E.
Object Type: Report
System: The UNT Digital Library
ALE3D Simulation and Measurement of Violence in a Fast Cookoff Experiment for LX-10 (open access)

ALE3D Simulation and Measurement of Violence in a Fast Cookoff Experiment for LX-10

Fast cookoff is of interest in the areas of fire hazard reduction and the development of directed energy systems for defense. During a fast cookoff (thermal explosion), high heat fluxes cause rapid temperature increases and ignition in thin boundary layers. We are developing ALE3D models to describe the thermal, chemical, and mechanical behavior during the heating, ignition, and explosive phases. The candidate models and numerical strategies are being evaluated using benchmark cookoff experiments. Fast cookoff measurements were made in a Scaled-Thermal-Explosion-eXperiment (STEX) for LX-10 (94.7% HMX, 5.3% Viton A) confined in a 4130 steel tube with reinforced end caps. Gaps were present at the side and top of the explosive charge to allow for thermal expansion. The explosive was heated until explosion using radiant heaters. Temperatures were measured using thermocouples positioned on the tube wall and in the explosive. During the explosion, the tube expansion and fragment velocities were measured with strain gauges, Photonic-Doppler-Velocimeters (PDVs), and micropower radar units. A fragment size distribution was constructed from fragments captured in Lexan panels. ALE3D models for chemical, thermal, and mechanical behavior were developed for the heating and explosive processes. A multi-step chemical kinetics model is employed for the HMX while a one-step …
Date: May 23, 2006
Creator: McClelland, M. A.; Maienschein, J. L.; Howard, W. M. & Dehaven, M. R.
Object Type: Article
System: The UNT Digital Library
Alloy Design and Development of Cast Cr-W-V Ferritic Steels for Improved High-Temperature Strength for Power Generation Applications (open access)

Alloy Design and Development of Cast Cr-W-V Ferritic Steels for Improved High-Temperature Strength for Power Generation Applications

Economic and environmental concerns demand that the power-generation industry seek increased efficiency for gas turbines. Higher efficiency requires higher operating temperatures, with the objective temperature for the hottest sections of new systems {approx} 593 C, and increasing to {approx} 650 C. Because of their good thermal properties, Cr-Mo-V cast ferritic steels are currently used for components such as rotors, casings, pipes, etc., but new steels are required for the new operating conditions. The Oak Ridge National Laboratory (ORNL) has developed new wrought Cr-W-V steels with 3-9% Cr, 2-3% W, 0.25% V (compositions are in wt.%), and minor amounts of additional elements. These steels have the strength and toughness required for turbine applications. Since cast alloys are expected to behave differently from wrought material, work was pursued to develop new cast steels based on the ORNL wrought compositions. Nine casting test blocks with 3, 9, and 11% Cr were obtained. Eight were Cr-W-V-Ta-type steels based on the ORNL wrought steels; the ninth was COST CB2, a 9Cr-Mo-Co-V-Nb cast steel, which was the most promising cast steel developed in a European alloy-development program. The COST CB2 was used as a control to which the new compositions were compared, and this also provided …
Date: September 23, 2006
Creator: Klueh, R. L.; Maziasz, P. J.; Vitek, J. M.; Evans, N. D. & Hashimoto, N.
Object Type: Report
System: The UNT Digital Library
The Analysis of Thin Wires Using Higher-Order Elements and Basis Functions (open access)

The Analysis of Thin Wires Using Higher-Order Elements and Basis Functions

Thin wire analysis was applied to curved wire segments in [1], but a special procedure was needed to evaluate the self and near-self terms. The procedure involved associating the singular behavior with a straight segment tangent to the curved source segment, permitting use of algorithms for straight wires. Recently, a procedure that avoids the singularity extraction for straight wires was presented in [2-4]. In this paper, the approach in [4] is applied to curved (or higher-order) wires using a procedure similar to that used in [1] for singularity extraction. Here, the straight tangent segment is used to determine the quadrature rules to be used on the curved segment. The result is a formulation that allows for a general mixture of higher-order basis functions [5] and higher-order wire segments.
Date: January 23, 2006
Creator: Champagne, N. J.; Wilton, D. R. & Rockway, J. W.
Object Type: Article
System: The UNT Digital Library
An Anti-Symmetric Lattice for High-Intensity Rapid Cycling Synchrotrons. (open access)

An Anti-Symmetric Lattice for High-Intensity Rapid Cycling Synchrotrons.

Rapid cycling synchrotrons (RCSs) are used in many high power facilities like spallation neutron sources and proton drivers to accumulate and accelerate proton beams. In such accelerators, beam collimation plays a crucial role in reducing the uncontrolled beam loss. Furthermore, injection and extraction sections often need to reside in dispersion-free regions to avoid couplings; sizeable drift space is needed to house the RF accelerating cavities; long, uninterrupted straights are desired to ease injection tuning and to raise collimation efficiency. Finally, the machine circumference needs to be small to reduce construction costs. In this paper, we present a lattice satisfying these needs. The lattice contains a drift created by a missing dipole near the peak dispersion to facilitate longitudinal collimation. The compact FODO arc allows easy orbit, tune, coupling, and chromatic correction. The doublets provide long uninterrupted straights. The four-fold lattice symmetry separates injection, extraction, and collimation to different straights. This lattice is adopted for the China Spallation Neutron Source (CSNS) synchrotron [1].
Date: June 23, 2006
Creator: Wei, J.; Wang, S.; Fang, S.-X.; Lee, Y. Y.; Machida, S.; Prior, C. et al.
Object Type: Article
System: The UNT Digital Library
THE APPLICATION OF SINGLE PARTICLE AEROSOL MASS SPECTROMETRY FOR THE DETECTION AND IDENTIFICATION OF HIGH EXPLOSIVES AND CHEMICAL WARFARE AGENTS (open access)

THE APPLICATION OF SINGLE PARTICLE AEROSOL MASS SPECTROMETRY FOR THE DETECTION AND IDENTIFICATION OF HIGH EXPLOSIVES AND CHEMICAL WARFARE AGENTS

Single Particle Aerosol Mass Spectrometry (SPAMS) was evaluated as a real-time detection technique for single particles of high explosives. Dual-polarity time-of-flight mass spectra were obtained for samples of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN); peaks indicative of each compound were identified. Composite explosives, Comp B, Semtex 1A, and Semtex 1H were also analyzed, and peaks due to the explosive components of each sample were present in each spectrum. Mass spectral variability with laser fluence is discussed. The ability of the SPAMS system to identify explosive components in a single complex explosive particle ({approx}1 pg) without the need for consumables is demonstrated. SPAMS was also applied to the detection of Chemical Warfare Agent (CWA) simulants in the liquid and vapor phases. Liquid simulants for sarin, cyclosarin, tabun, and VX were analyzed; peaks indicative of each simulant were identified. Vapor phase CWA simulants were adsorbed onto alumina, silica, Zeolite, activated carbon, and metal powders which were directly analyzed using SPAMS. The use of metal powders as adsorbent materials was especially useful in the analysis of triethyl phosphate (TEP), a VX stimulant, which was undetectable using SPAMS in the liquid phase. The capability of SPAMS to detect high explosives and CWA …
Date: October 23, 2006
Creator: Martin, A
Object Type: Thesis or Dissertation
System: The UNT Digital Library
An Archaeological Survey of the Proposed Sand Spring Substation, Wood County, Texas (open access)

An Archaeological Survey of the Proposed Sand Spring Substation, Wood County, Texas

A report of a pedestrian archaeological survey of 2,250 feet proposed access route for the Sand Spring Substation.
Date: February 23, 2006
Creator: Todd, Jesse
Object Type: Report
System: The Portal to Texas History
Arctic Petroleum Technology Developments (open access)

Arctic Petroleum Technology Developments

This report discusses the ongoing debate about whether or not to open the Arctic National Wildlife Refuge (ANWR) for energy development, specifically the North Slope of Alaska for petroleum exploration and development. This report discusses the arguments for and against such development, especially with regard to environmental impacts.
Date: January 23, 2006
Creator: Gelb, Bernard A.; Corn, M. Lynne & Twyman, Terry R.
Object Type: Report
System: The UNT Digital Library
Armenia, Azerbaijan, and Georgia: Political Developments and Implications for U.S. Interests (open access)

Armenia, Azerbaijan, and Georgia: Political Developments and Implications for U.S. Interests

This report is categorized into nine categories: (I) Most Recent Developments, (II) Background and Analysis, (III) Overview of U.S. Policy Concerns, (IV) Obstacles to peace and Independence, (V) The South Caucasus's External Security Context, (VI) U.S. Aid Overview, (VII) U.S. Security Assistance, (VIII) U.S. Trade an Investment, and (IX) Legislation.
Date: February 23, 2006
Creator: Nichol, Jim
Object Type: Report
System: The UNT Digital Library
Asbestos Litigation: Prospects for Legislative Resolution (open access)

Asbestos Litigation: Prospects for Legislative Resolution

This report is on Asbestos Litigation: Prospects for Legislative Resolution.
Date: August 23, 2006
Creator: Rappaport, Edward
Object Type: Report
System: The UNT Digital Library
ATLAS TrackingEvent Data Model -- 12.0.0 (open access)

ATLAS TrackingEvent Data Model -- 12.0.0

In this report the event data model (EDM) relevant for tracking in the ATLAS experiment is presented. The core component of the tracking EDM is a common track object which is suited to describe tracks in the innermost tracking sub-detectors and in the muon detectors in offline as well as online reconstruction. The design of the EDM was driven by a demand for modularity and extensibility while taking into account the different requirements of the clients. The structure of the track object and the representation of the tracking-relevant information are described in detail.
Date: July 23, 2006
Creator: ATLAS; Akesson, F.; Atkinson, T.; Costa, M.J.; Elsing, M.; Fleischmann, S. et al.
Object Type: Article
System: The UNT Digital Library
Automation&Characterization of US Air Force Bench Top Wind Tunnels - Summary Report (open access)

Automation&Characterization of US Air Force Bench Top Wind Tunnels - Summary Report

The United States Air Force Precision Measurement Equipment Laboratories (PMEL) calibrate over 1,000 anemometer probes per year. To facilitate a more efficient calibration process for probe-style anemometers, the Air Force Metrology and Calibration Program underwent an effort to modernize the existing PMEL bench top wind tunnels. Through a joint effort with the Department of Energy's Oak Ridge National Laboratory, the performance of PMEL wind tunnels was improved. The improvement consisted of new high accuracy sensors, automatic data acquisition, and a software-driven calibration process. As part of the wind tunnel upgrades, an uncertainty analysis was completed, laser Doppler velocimeter profiling was conducted to characterize the velocities at probe locations in the wind tunnel, and pitot tube calibrations of the wind tunnel were verified. The bench top wind tunnel accuracy and repeatability has been measured for nine prototype wind tunnel systems and valuable field experience has been gained with these wind tunnels at the PMELs. This report describes the requirements for the wind tunnel improvements along with actual implementation strategies and details. Lessons-learned from the automation, the velocity profiling, and the software-driven calibration process will also be discussed.
Date: March 23, 2006
Creator: Hardy, J. E.
Object Type: Report
System: The UNT Digital Library
Barrier Coatings for Refractory Metals and Superalloys (open access)

Barrier Coatings for Refractory Metals and Superalloys

In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life.
Date: February 23, 2006
Creator: Sabol, SM; Randall, BT; Edington, JD; Larkin, CJ & Close, BJ
Object Type: Report
System: The UNT Digital Library
Beam Pipe Desorption Rate in Rhic. (open access)

Beam Pipe Desorption Rate in Rhic.

In the past, an increase of beam intensity in RHIC has caused several decades of pressure rises in the warm sections during operation. This has been a major factor limiting the RHIC luminosity. About 430 meters of NEG coated beam pipes have been installed in the warm sections to ameliorate this problem. Beam ion induced desorption is one possible cause of pressure rises. A series beam studies in RHIC has been dedicated to estimate the desorption rate of various beam pipes (regular and NEG coated) at various warm sections. Correctors were used to generate local beam losses and consequently local pressure rises. The experimental results are presented and analyzed in this paper.
Date: June 23, 2006
Creator: Huang, H.; Fischer, W.; He, P.; Hseuh, H. C.; Iriso, U.; Ptitsyn, V. et al.
Object Type: Article
System: The UNT Digital Library
Beyond Boltzmann-Gibbs statistics: Maximum entropy hyperensemblesout-of-equilibrium (open access)

Beyond Boltzmann-Gibbs statistics: Maximum entropy hyperensemblesout-of-equilibrium

What is the best description that we can construct of athermodynamic system that is not in equilibrium, given only one, or afew, extra parameters over and above those needed for a description ofthe same system at equilibrium? Here, we argue the most appropriateadditional parameter is the non-equilibrium entropy of the system, andthat we should not attempt to estimate the probability distribution ofthe system, but rather the metaprobability (or hyperensemble) that thesystem is described by a particular probability distribution. The resultis an entropic distribution with two parameters, one a non-equilibriumtemperature, and the other a measure of distance from equilibrium. Thisdispersion parameter smoothly interpolates between certainty of acanonical distribution at equilibrium and great uncertainty as to theprobability distribution as we move away from equilibrium. We deducethat, in general, large, rare fluctuations become far more common as wemove away from equilibrium.
Date: February 23, 2006
Creator: Crooks, Gavin E.
Object Type: Article
System: The UNT Digital Library
Border Security and Military Support: Legal Authorizations and Restrictions (open access)

Border Security and Military Support: Legal Authorizations and Restrictions

The military generally provides support to law enforcement and immigration authorities along the southern border. Reported escalations in violence and illegal immigration, however, have prompted some lawmakers to reevaluate the extent and type of military support that occurs in the border region. President Bush has reportedly announced an interest in sending National Guard troops to support the Border Patrol. Addressing domestic laws and activities with the military, however, might run afoul of the Posse Comitatus Act, which prohibits use of the armed forces to perform the tasks of civilian law enforcement unless explicitly authorized. There are alternative legal authorities for deploying the National Guard, and the precise scope of permitted activities and funds may vary with the authority exercised.
Date: May 23, 2006
Creator: Vina, Stephen R
Object Type: Report
System: The UNT Digital Library
The Budget for Fiscal Year 2006 (open access)

The Budget for Fiscal Year 2006

This report discusses the President's fiscal year (FY) 2007 budget (February 2006) included a revised FY2006 deficit estimate of $423 billion, $72 billion larger than its previous estimate (July 2005) and $53 billion larger than its original deficit estimate in February 2005.
Date: October 23, 2006
Creator: Winters, Philip D.
Object Type: Report
System: The UNT Digital Library