Gamma Spectrum from Neutron Capture on Tungsten Isotopes (open access)

Gamma Spectrum from Neutron Capture on Tungsten Isotopes

None
Date: May 20, 2010
Creator: Hurst, A. M.; Summers, N. C.; Sleaford, B.; Firestone, R.; Belgya, T. & Revay, Z. S.
Object Type: Article
System: The UNT Digital Library
Heterogeneous nucleation of ice on anthropogenic organic particles collected in Mexico City (open access)

Heterogeneous nucleation of ice on anthropogenic organic particles collected in Mexico City

This study reports on heterogeneous ice nucleation activity of predominantly organic (or coated with organic material) anthropogenic particles sampled within and around the polluted environment of Mexico City. The onset of heterogeneous ice nucleation was observed as a function of particle temperature (Tp), relative humidity (RH), nucleation mode, and particle chemical composition which is influenced by photochemical atmospheric aging. Particle analyses included computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). In contrast to most laboratory studies employing proxies of organic aerosol, we show that anthropogenic organic particles collected in Mexico City can potentially induce ice nucleation at experimental conditions relevant to cirrus formation. The results suggest a new precedent for the potential impact of organic particles on ice cloud formation and climate.
Date: June 20, 2010
Creator: Knopf, D. A.; Wang, B.; Laskin, A.; Moffet, R. C. & Gilles, M. K.
Object Type: Article
System: The UNT Digital Library
NEAR FIELD MODELING OF SPE1 EXPERIMENT AND PREDICTION OF THE SECOND SOURCE PHYSICS EXPERIMENTS (SPE2) (open access)

NEAR FIELD MODELING OF SPE1 EXPERIMENT AND PREDICTION OF THE SECOND SOURCE PHYSICS EXPERIMENTS (SPE2)

Motion along joints and fractures in the rock has been proposed as one of the sources of near-source shear wave generation, and demonstrating the validity of this hypothesis is a focal scientific objective of the source physics experimental campaign in the Climax Stock granitic outcrop. A modeling effort has been undertaken by LLNL to complement the experimental campaign, and over the long term provide a validated computation capability for the nuclear explosion monitoring community. The approach involves performing the near-field nonlinear modeling with hydrodynamic codes (e.g., GEODYN, GEODYN-L), and the far-field seismic propagation with an elastic wave propagation code (e.g., WPP). the codes will be coupled together to provide a comprehensive source-to-sensor modeling capability. The technical approach involves pre-test predictions of each of the SPE experiments using their state of the art modeling capabilities, followed by code improvements to alleviate deficiencies identified in the pre-test predictions. This spiral development cycle wherein simulations are used to guide experimental design and the data from the experiment used to improve the models is the most effective approach to enable a transition from the descriptive phenomenological models in current use to the predictive, hybrid physics models needed for a science-based modeling capability for nuclear …
Date: October 20, 2011
Creator: Antoun, T; Xu, H; Vorobiev, O & Lomov, I
Object Type: Report
System: The UNT Digital Library
Flow Analysis Baseline Heated Flow Turbulence Model Comparison (open access)

Flow Analysis Baseline Heated Flow Turbulence Model Comparison

None
Date: January 20, 2011
Creator: Sutton, S B
Object Type: Report
System: The UNT Digital Library
ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLES POURED AUGUST 29, 2012 (open access)

ANALYTICAL RESULTS OF MOX COLEMANITE CONCRETE SAMPLES POURED AUGUST 29, 2012

The Mixed Oxide Fuel Fabrication Facility (MFFF) will use colemanite bearing concrete neutron absorber panels credited with attenuating neutron flux in the criticality design analyses and shielding operators from radiation. The Savannah River National Laboratory is tasked with measuring the total density, partial hydrogen density, and partial boron density of the colemanite concrete. Samples poured 8/29/12 were received on 9/20/2012 and analyzed. The average total density of each of the samples measured by the ASTM method C 642 was within the lower bound of 1.88 g/cm{sup 3}. The average partial hydrogen density of samples 8.6.1, 8.7.1, and 8.5.3 as measured using method ASTM E 1311 met the lower bound of 6.04E-02 g/cm{sup 3}. The average measured partial boron density of each sample met the lower bound of 1.65E-01 g/cm{sup 3} measured by the ASTM C 1301 method. The average partial hydrogen density of samples 8.5.1, 8.6.3, and 8.7.3 did not meet the lower bound. The samples, as received, were not wrapped in a moist towel as previous samples and appeared to be somewhat drier. This may explain the lower hydrogen partial density with respect to previous samples.
Date: December 20, 2012
Creator: Best, D.; Cozzi, A. & Reigel, M.
Object Type: Report
System: The UNT Digital Library
Dark Matter Profiles and Annihilation in Dwarf Spheroidal Galaxies: Prospectives for Present and Future Gamma-Ray Observatories - I. the Classical DSphs (open access)

Dark Matter Profiles and Annihilation in Dwarf Spheroidal Galaxies: Prospectives for Present and Future Gamma-Ray Observatories - I. the Classical DSphs

None
Date: March 20, 2013
Creator: Charbonnier, A.; /Paris U., VI-VII; Combet, C.; U., /Leicester; Daniel, M.; U., /Durham et al.
Object Type: Article
System: The UNT Digital Library
Guideline for the Implementation of Safeguards into the Design Process for Nuclear Reactors (open access)

Guideline for the Implementation of Safeguards into the Design Process for Nuclear Reactors

None
Date: May 20, 2013
Creator: Farley, D
Object Type: Report
System: The UNT Digital Library
Wake fields effects for the eRHIC project (open access)

Wake fields effects for the eRHIC project

An Energy Recovery Linac (ERL) with a high peak electron bunch current is proposed for the Electron-Ion collider (eRHIC) project at the Brookhaven National Laboratory. The present design is based on the multi-pass electron beam transport in existing tunnel of the Relativistic Heavy Ion Collider (RHIC). As a result of a high peak current and a very long beam transport, consideration of various collective beam dynamics effects becomes important. Here we summarize effects of the coherent synchrotron radiation, resistive wall, accelerating cavities and wall roughness on the resulting energy spread and energy loss for several scenarios of the eRHIC project.
Date: May 20, 2012
Creator: V., Fedotov A.; Belomestnykh, S.; Kayran, D.; Litvinenko, V. & Ptitsyn, V.
Object Type: Article
System: The UNT Digital Library
Dynamic Simulation Studies of the Frequency Response of the Three U.S. Interconnections with Increased Wind Generation (open access)

Dynamic Simulation Studies of the Frequency Response of the Three U.S. Interconnections with Increased Wind Generation

Utility Systems Efficiencies, Inc. was tasked by Lawrence Berkeley National Laboratory (LBNL) to conduct dynamic simulation studies of the three U.S. interconnections (Eastern, Western, and Texas). The simulations were prepared in support of LBNL's project for the Federal Energy Regulatory Commission to study frequency-response-related issues that must be addressed to operate the power system reliably with large amounts of variable renewable generation. The objective of the simulation studies of each interconnection was to assess the effects of different amounts of wind generation on frequency behavior of each interconnection following a sudden loss of generation. The scenarios created to study these effects considered an operating circumstance in which system load is at or close to its minimum. The event studied was the sudden loss of the largest amount of generation recorded within each interconnection. The simulations calculated the impact of this event on interconnection frequency for three levels of wind generation. In addition to varying the amount of wind generation, the simulations varied the amount of operating reserves between a high level representative of current operating practices and a low level representative of the minimum required by present operating rules.
Date: December 20, 2010
Creator: Mackin, Peter; Daschmans, R.; Williams, B.; Haney, B.; Hung, R. & Ellis, J.
Object Type: Report
System: The UNT Digital Library
Electron Coherence in Mesoscopic Structures (open access)

Electron Coherence in Mesoscopic Structures

The recent rapid progress in nanofabrication and experimental techniques made it possible to investigate a variety of meso-- and nano--scale systems, which were unavailable only a few years ago. Examples include fabrication of high-quality quantum wires in semiconductor heterostructures, of nanoscale hybrid superconductor--normal metal structures, and of a variety of novel (and much smaller) quantum dot and q-bit designs. These technological advances have led to formulation of a number of condensed matter theory problems which are equally important for applications and for the fundamental science. The present proposal aims at filling the exposed gaps in knowledge and at facilitating further development of experimental and theoretical physics of nanoscale structures. Specifically, the two PIs address the following issues: (i) The theory of interacting electrons in a quantum wire which accounts adequately for the non-linear dispersion relation of the electrons. The existing approaches rely on models with {\em linearized} electron spectrum, which fall short of addressing a growing list of experimentally relevant phenomena. (ii) Dynamics of hybrid normal--superconducting systems. A reliable treatment of dissipative phenomena in such structures is not developed as of yet, while rapid progress in fabrication makes finding the proper theoretical treatment methods highly desirable. (iii)~The fundamental limits on …
Date: March 20, 2011
Creator: Kamenev, Alex & Glazman, Leonid
Object Type: Report
System: The UNT Digital Library
Deposition and in-situ characterization of alkali antimonide photocathodes (open access)

Deposition and in-situ characterization of alkali antimonide photocathodes

N/A
Date: May 20, 2012
Creator: Liang, X.; Ben-Zvi, Ilan; Ruiz-Oses, M.; Smedley, J.; Attenkofer, K.; Vecchione, T. et al.
Object Type: Article
System: The UNT Digital Library
Fireside Corrosion in Oxy-fuel Combustion of Coal (open access)

Fireside Corrosion in Oxy-fuel Combustion of Coal

Oxy-fuel combustion is burning a fuel in oxygen rather than air. The low nitrogen flue gas that results is relatively easy to capture CO{sub 2} from for reuse or sequestration. Corrosion issues associated with the environment change (replacement of much of the N{sub 2} with CO{sub 2} and higher sulfur levels) from air- to oxy-firing were examined. Alloys studied included model Fe-Cr alloys and commercial ferritic steels, austenitic steels, and nickel base superalloys. The corrosion behavior is described in terms of corrosion rates, scale morphologies, and scale/ash interactions for the different environmental conditions.
Date: May 20, 2012
Creator: Holcomb, G. R.; Tylczak, J.; Meier, G. H.; Lutz, B.; Jung, K.; Mu, N. et al.
Object Type: Article
System: The UNT Digital Library
EFFECT OF COMPRESSION ON CONDUCTIVITY AND MORPHOLOGY OF PFSA MEMBRANES (open access)

EFFECT OF COMPRESSION ON CONDUCTIVITY AND MORPHOLOGY OF PFSA MEMBRANES

Polymer-Electrolyte-Fuel-Cells (PEFCs) are promising candidates for powering vehicles and portable devices using renewable-energy sources. The core of a PEFC is the solid electrolyte membrane that conducts protons from anode to cathode, where water is generated. The conductivity of the membrane, however, depends on the water content of the membrane, which is strongly related to the cell operating conditions. The membrane and other cell components are typically compressed to minimize various contact resistances. Moreover, the swelling of a somewhat constrained membrane in the cell due to the humidity changes generates additional compressive stresses in the membrane. These external stresses are balanced by the internal swelling pressure of the membrane and change the swelling equilibrium. It was shown using a fuel-cell setup that compression could reduce the water content of the membrane or alter the cell resistance. Nevertheless, the effect of compression on the membrane’s transport properties is yet to be understood, as well as its implications in the structure-functions relationships of the membrane. We previously studied, both experimentally and theoretically, how compression affects the water content of the membrane.6 However, more information is required the gain a fundamental understanding of the compression effects. In this talk, we present the results of …
Date: July 20, 2011
Creator: Kusoglu, Ahmet; Weber, Adam; Jiang, Ruichin & Gittleman, Craig
Object Type: Article
System: The UNT Digital Library
Intrinsic Chevrolets at the SSC (open access)

Intrinsic Chevrolets at the SSC

None
Date: May 20, 2013
Creator: Brodsky, Stanley
Object Type: Article
System: The UNT Digital Library
RHIC spin flipper commissioning results (open access)

RHIC spin flipper commissioning results

The five AC dipole RHIC spin flipper design in the RHIC Blue ring was first tested during the RHIC 2012 polarized proton operation. The advantage of this design is to eliminate the vertical coherent betatron oscillations outside the spin flipper. The closure of each ac dipole vertical bump was measured with orbital response as well as spin. The effect of the rotating field on the spin motion by the spin flipper was also confirmed by measuring the suppressed resonance at Q{sub s} = 1 - Q{sub osc}.
Date: May 20, 2012
Creator: M., Bai; Roser, T.; Dawson, C.; Kewisch, J.; Makdisi, Y.; Oddo, P. et al.
Object Type: Article
System: The UNT Digital Library
Seismic reflection imaging of underground cavities using open-source software (open access)

Seismic reflection imaging of underground cavities using open-source software

The Comprehensive Nuclear Test Ban Treaty (CTBT) includes provisions for an on-site inspection (OSI), which allows the use of specific techniques to detect underground anomalies including cavities and rubble zones. One permitted technique is active seismic surveys such as seismic refraction or reflection. The purpose of this report is to conduct some simple modeling to evaluate the potential use of seismic reflection in detecting cavities and to test the use of open-source software in modeling possible scenarios. It should be noted that OSI inspections are conducted under specific constraints regarding duration and logistics. These constraints are likely to significantly impact active seismic surveying, as a seismic survey typically requires considerable equipment, effort, and expertise. For the purposes of this study, which is a first-order feasibility study, these issues will not be considered. This report provides a brief description of the seismic reflection method along with some commonly used software packages. This is followed by an outline of a simple processing stream based on a synthetic model, along with results from a set of models representing underground cavities. A set of scripts used to generate the models are presented in an appendix. We do not consider detection of underground facilities in …
Date: December 20, 2011
Creator: Mellors, R J
Object Type: Report
System: The UNT Digital Library
Laser-Plasma Interaction Experiments with Single and Multiple NIF Beams (open access)

Laser-Plasma Interaction Experiments with Single and Multiple NIF Beams

None
Date: June 20, 2012
Creator: Strozzi, D. J.; Moody, J. D.; Robey, H. F.; Divol, L.; Michel, P.; Berger, R. L. et al.
Object Type: Article
System: The UNT Digital Library
Simulations of multipacting in the cathode stalk and FPC of 112 MHz superconducting electron gun (open access)

Simulations of multipacting in the cathode stalk and FPC of 112 MHz superconducting electron gun

A 112 MHz superconducting quarter-wave resonator electron gun will be used as the injector of the Coherent Electron Cooling (CEC) proof-of-principle experiment at BNL. Furthermore, this electron gun can be used for testing of the performance of various high quantum efficiency photocathodes. In a previous paper, we presented the design of the cathode stalks and a Fundamental Power Coupler (FPC). In this paper we present updated designs of the cathode stalk and FPC. Multipacting in the cathode stalk and FPC was simulated using three different codes. All simulation results show no serious multipacting in the cathode stalk and FPC.
Date: May 20, 2012
Creator: Xin, T.; Ben-Zvi, Ilan; Belomestnykh, S.; Chang, X.; Rao, T.; Skaritka, J. et al.
Object Type: Article
System: The UNT Digital Library
A NORMETEX MODEL 15 M3/HR WATER VAPOR PUMPING TEST (open access)

A NORMETEX MODEL 15 M3/HR WATER VAPOR PUMPING TEST

Tests were performed using a Model 15 m{sup 3}/hr Normetex vacuum pump to determine if pump performance degraded after pumping a humid gas stream. An air feed stream containing 30% water vapor was introduced into the pump for 365 hours with the outlet pressure of the pump near the condensation conditions of the water. Performance of the pump was tested before and after the water vapor pumping test and indicated no loss in performance of the pump. The pump also appeared to tolerate small amounts of condensed water of short duration without increased noise, vibration, or other adverse indications. The Normetex pump was backed by a dual-head diaphragm pump which was affected by the condensation of water and produced some drift in operating conditions during the test.
Date: December 20, 2010
Creator: Klein, J.; Fowley, M. & Steeper, T.
Object Type: Article
System: The UNT Digital Library
User's Manual for BEST-Dairy: Benchmarking and Energy/water-Saving Tool (BEST) for the Dairy Processing Industry (Version 1.2) (open access)

User's Manual for BEST-Dairy: Benchmarking and Energy/water-Saving Tool (BEST) for the Dairy Processing Industry (Version 1.2)

This User's Manual summarizes the background information of the Benchmarking and Energy/water-Saving Tool (BEST) for the Dairy Processing Industry (Version 1.2, 2011), including'Read Me' portion of the tool, the sections of Introduction, and Instructions for the BEST-Dairy tool that is developed and distributed by Lawrence Berkeley National Laboratory (LBNL).
Date: April 20, 2011
Creator: Xu, T.; Ke, J. & Sathaye, J.
Object Type: Report
System: The UNT Digital Library
Preliminary Study on Emittance Growth in the LHEC Recirculating Linac (open access)

Preliminary Study on Emittance Growth in the LHEC Recirculating Linac

In this paper, we estimate the emittance growth in the LHeC recirculating Linac, the lattice design of which is presented in another paper of IPAC10 proceedings. The possible sources for emittance growth included here are: energy spread from RF acceleration in the SRF (superconducting RF) linac together with large chromatic effects from the lattice, and synchrotron radiation (SR) fluctuations in the recirculating arcs. 6-D multi-particle tracking is launched to calculate the emittance from the statistical point of view. The simulation results are also compared with a theoretical estimation.
Date: May 20, 2011
Creator: Sun, Yi-Peng; Adolphsen, Chris; /SLAC; Zimmermann, Frank & /CERN
Object Type: Article
System: The UNT Digital Library
he Impact of Primary Marine Aerosol on Atmospheric Chemistry, Radiation and Climate: A CCSM Model Development Study (open access)

he Impact of Primary Marine Aerosol on Atmospheric Chemistry, Radiation and Climate: A CCSM Model Development Study

This project examined the potential large-scale influence of marine aerosol cycling on atmospheric chemistry, physics and radiative transfer. Measurements indicate that the size-dependent generation of marine aerosols by wind waves at the ocean surface and the subsequent production and cycling of halogen-radicals are important but poorly constrained processes that influence climate regionally and globally. A reliable capacity to examine the role of marine aerosol in the global-scale atmospheric system requires that the important size-resolved chemical processes be treated explicitly. But the treatment of multiphase chemistry across the breadth of chemical scenarios encountered throughout the atmosphere is sensitive to the initial conditions and the precision of the solution method. This study examined this sensitivity, constrained it using high-resolution laboratory and field measurements, and deployed it in a coupled chemical-microphysical 3-D atmosphere model. First, laboratory measurements of fresh, unreacted marine aerosol were used to formulate a sea-state based marine aerosol source parameterization that captured the initial organic, inorganic, and physical conditions of the aerosol population. Second, a multiphase chemical mechanism, solved using the Max Planck Institute for Chemistry’s MECCA (Module Efficiently Calculating the Chemistry of the Atmosphere) system, was benchmarked across a broad set of observed chemical and physical conditions in the …
Date: May 20, 2013
Creator: Keene, William C. & Long, Michael S.
Object Type: Report
System: The UNT Digital Library
Electrical and optical properties of p-type InN (open access)

Electrical and optical properties of p-type InN

We have performed comprehensive studies of optical, thermoelectric and electrical properties of Mg doped InN with varying Mg doping levels and sample thicknesses. Room temperature photoluminescence spectra show a Mg acceptor related emission and the thermopower provides clear evidence for the presence of mobile holes. Although the effects of the hole transport are clearly observed in the temperature dependent electrical properties, the sign of the apparent Hall coefficient remains negative in all samples. We show that the standard model of two electrically well connected layers (n-type surface electron accumulation and p-type bulk) does not properly describe Hall effect in p-type InN.
Date: November 20, 2011
Creator: Mayer, M. A.; Choi, S.; Bierwagen, O.; Smith, H. M., III; Haller, E. E.; Speck, J. S. et al.
Object Type: Article
System: The UNT Digital Library
Secondary-electron emission from hydrogen-terminated diamond (open access)

Secondary-electron emission from hydrogen-terminated diamond

Diamond amplifiers demonstrably are an electron source with the potential to support high-brightness, high-average-current emission into a vacuum. We recently developed a reliable hydrogenation procedure for the diamond amplifier. The systematic study of hydrogenation resulted in the reproducible fabrication of high gain diamond amplifier. Furthermore, we measured the emission probability of diamond amplifier as a function of the external field and modelled the process with resulting changes in the vacuum level due to the Schottky effect. We demonstrated that the decrease in the secondary electrons average emission gain was a function of the pulse width and related this to the trapping of electrons by the effective NEA surface. The findings from the model agree well with our experimental measurements. As an application of the model, the energy spread of secondary electrons inside the diamond was estimated from the measured emission.
Date: May 20, 2012
Creator: Wang, E.; Ben-Zvi, Ilan; Rao, T.; Wu, Q.; Dimitrov, D. A. & Xin, T.
Object Type: Article
System: The UNT Digital Library