Implementation of the MPC and A Operations Monitorying (MOM) System at JSC PO Sevmas (open access)

Implementation of the MPC and A Operations Monitorying (MOM) System at JSC PO Sevmas

The Material Protection, Control and Accounting (MPC&A) Program has been working since 1994 with nuclear sites in Russia to upgrade the physical protection (PP) and material control and accounting (MC&A) functions at facilities containing weapons usable nuclear material. In early 2001, the MPC&A program initiated the MPC&A Operations Monitoring (MOM) Project to monitor facilities where MPC&A upgrades have been installed to provide increased confidence that personnel are present and vigilant, provide confidence that security procedures are being properly performed and provide additional assurance that nuclear materials have not been stolen. The MOM project began as a pilot project at the Moscow State Engineering Physics Institute (MEPhI) and a MOM system was successfully installed in October 2001. Following the success of the MEPhI pilot project, the MPC&A Program expanded the installation of MOM systems to several other Russian facilities, including the JSC 'PO' Sevmash', Severodvinsk, Russia. The MOM system was made operational at Sevmash in September, 2008. This paper will discuss the objectives of the MOM system installed at Sevmash and indicate how the objectives influenced the development of the conceptual design. The paper will also describe activities related to installation of the infrastructure and the MOM system at Sevmash. Experience …
Date: July 11, 2010
Creator: Monogarov, Andrei; Taranenko, Vladimir; Serov, Andrei; Duncan, Cristen; Brownell, Lorilee; Pratt, William T. et al.
Object Type: Article
System: The UNT Digital Library
The Influence of Cloud Microphysics and Radiation on the Response of Water Vapor and Clouds to Climate Change (open access)

The Influence of Cloud Microphysics and Radiation on the Response of Water Vapor and Clouds to Climate Change

Uncertainties in representing the atmospheric water cycle are major obstacles to the accurate prediction of future climate. This project focused on addressing some of these uncertainties by implementing new physics for convection and radiation into the NCAR Community Atmosphere Model (CAM). To better understand and eventually better represent these processes in this major national climate model, we modified CAM3.5 to use the convection and cloud schemes developed by the Massachusetts Institute of Technology (MIT) and the RRTMG rapid radiation code for global climate models developed by Atmospheric and Environmental Research, Inc. (AER). The impact of the new physics on the CAM3.5 simulation of convection on diurnal and intra-seasonal scales, on intra-seasonal oscillations and on the distribution of water vapor has been investigated. In addition, the MIT and AER physics packages have been incorporated and tested in combination within the Weather Research and Forecasting (WRF) regional forecast model for the purpose of evaluating and improving convective and radiative processes on time scales appropriate to weather simulations. It has been found that the application of the AER radiation and MIT convection produces significant improvements in the modeled diurnal cycle of convection, especially over land, in the NCAR climate model. However, both the …
Date: November 11, 2010
Creator: Emanuel, Kerry & Iacono, Michael J.
Object Type: Report
System: The UNT Digital Library
Influence of Incision Location on Transmitter Loss, Healing, Incision Lengths, Suture Retention, and Growth of Juvenile Chinook Salmon (open access)

Influence of Incision Location on Transmitter Loss, Healing, Incision Lengths, Suture Retention, and Growth of Juvenile Chinook Salmon

In this study, conducted by Pacific Northwest National Laboratory for the U.S. Army Corps of Engineers, Portland District, we measured differences in survival and growth, incision openness, transmitter loss, wound healing, and erythema among abdominal incisions on the linea alba, lateral and parallel to the linea alba (muscle-cutting), and following the underlying muscle fibers (muscle-sparing). A total of 936 juvenile Chinook salmon were implanted with both Juvenile Salmon Acoustic Tracking System transmitters (0.43 g dry) and passive integrated transponder tags. Fish were held at 12°C (n = 468) or 20°C (n = 468) and examined once weekly over 98 days. We found survival and growth did not differ among incision groups or between temperature treatment groups. Incisions on the linea alba had less openness than muscle-cutting and muscle-sparing incisions during the first 14 days when fish were held at 12°C or 20°C. Transmitter loss was not different among incision locations by day 28 when fish were held at 12°C or 20°C. However, incisions on the linea alba had greater transmitter loss than muscle-cutting and muscle-sparing incisions by day 98 at 12°C. Results for wound closure and erythema differed among temperature groups. Results from our study will be used to improve …
Date: May 11, 2010
Creator: Panther, Jennifer L.; Brown, Richard S.; Gaulke, Greggory L.; Woodley, Christa M. & Deters, Katherine A.
Object Type: Report
System: The UNT Digital Library
AN INTEGRATED BIOLOGICAL CONTROL SYSTEM AT HANFORD (open access)

AN INTEGRATED BIOLOGICAL CONTROL SYSTEM AT HANFORD

In 1999 an integrated biological control system was instituted at the U.S. Department of Energy's Hanford Site. Successes and changes to the program needed to be communicated to a large and diverse mix of organizations and individuals. Efforts at communication are directed toward the following: Hanford Contractors (Liquid or Tank Waste, Solid Waste, Environmental Restoration, Science and Technology, Site Infrastructure), General Hanford Employees, and Hanford Advisory Board (Native American Tribes, Environmental Groups, Local Citizens, Washington State and Oregon State regulatory agencies). Communication was done through direct interface meetings, individual communication, where appropriate, and broadly sharing program reports. The objectives of the communication efforts was to have the program well coordinated with Hanford contractors, and to have the program understood well enough that all stakeholders would have confidence in the work performed by the program to reduce or elimated spread of radioactive contamination by biotic vectors. Communication of successes and changes to an integrated biological control system instituted in 1999 at the Department of Energy's Hanford Site have required regular interfaces with not only a diverse group of Hanford contractors (i.e., those responsible for liquid or tank waste, solid wastes, environmental restoration, science and technology, and site infrastructure), and general Hanford …
Date: February 11, 2010
Creator: AR, JOHNSON; JG, CAUDILL; RF, GIDDINGS; JM, RODRIGUEZ; RC, ROOS & JW, WILDE
Object Type: Article
System: The UNT Digital Library
Integrating the Molecular Machines of Mercury Detoxification into Host Cell Biology (open access)

Integrating the Molecular Machines of Mercury Detoxification into Host Cell Biology

Integrating the Molecular Machines of Mercury Detoxification into Host Cell Biology The bacterial mercury resistance (mer) operon, one of the most evolutionarily successful genetic loci in any defined organism, detoxifies organic and inorganic mercury compounds. Several major biotic processes in the global Hg(II) cycle are carried out by bacteria with this highly mobile detoxification locus that occurs in Gram negative and high and low GC Gram positive bacteria. The functions of many individual mer operon components are well described, so we aim to dissect the higher order interactions of the enzymes, transporters, and regulators of this paradigm metal metabolizing system with each other and with the larger metabolism of the host cell. Understanding how this ubiquitous detoxification system fits into the biology and ecology of its bacterial host is essential to guide interventions that support and enhance Hg remediation. Specifically, we will test the hypotheses that: (a) the organomercurial lyase, MerB, and the mercuric reductase, MerA, act synergistically together and with the membrane-bound Hg(II) transporters, MerT and MerC, to detoxify mercurials; (b) the interaction of the metalloregulator MerR with RNA polymerase (RNAP) and with its DNA binding site, MerO, modulates its metal response, and interaction with its antagonist, MerD, prevents …
Date: March 11, 2010
Creator: Summers, Anne O
Object Type: Report
System: The UNT Digital Library
Internal Energies of Ion-Sputtered Neutral Tryptophan and Thymine Molecules Determined by Vacuum Ultraviolet Photoionization (open access)

Internal Energies of Ion-Sputtered Neutral Tryptophan and Thymine Molecules Determined by Vacuum Ultraviolet Photoionization

Vacuum ultraviolet photoionization coupled to secondary neutral mass spectrometry (VUV-SNMS) of deposited tryptophan and thymine films are performed at the Chemical Dynamics Beamline. The resulting mass spectra show that while the intensity of the VUV-SNMS signal is lower than the corresponding secondary ion mass spectroscopy (SIMS) signal, the mass spectra are significantly simplified in VUV-SNMS. A detailed examination of tryptophan and thymine neutral molecules sputtered by 25 keV Bi3 + indicates that the ion-sputtered parent molecules have ~;;2.5 eV of internal energy. While this internal energy shifts the appearance energy of the photofragment ions for both tryptophan and thymine, it does not change the characteristic photoionizaton efficiency (PIE) curves of thymine versus photon energy. Further analysis of the mass spectral signals indicate that approximately 80 neutral thymine molecules and 400 tryptophan molecules are sputtered per incident Bi3 + ion. The simplified mass spectra and significant characteristic ion contributions to the VUV-SNMS spectra indicate the potential power of the technique for organic molecule surface analysis.
Date: March 11, 2010
Creator: Zhou, Jia; Takahashi, Lynelle; Wilson, Kevin R.; Leone, Stephen R. & Ahmed, Musahid
Object Type: Article
System: The UNT Digital Library
INTERPRETATION OF AIRBORNE ELECTROMAGNETIC AND MAGNETIC DATA IN THE 600 AREA (open access)

INTERPRETATION OF AIRBORNE ELECTROMAGNETIC AND MAGNETIC DATA IN THE 600 AREA

As part of the 200-PO-1 Phase I geophysical surveys, Fugro Airborne Surveys was contracted to collect airborne electromagnetic (EM) and magnetic surveys of the Hanford Site 600 Area. Two helicopter survey systems were used with the HeliGEOTEM{reg_sign} time domain portion flown between June 19th and June 20th, 2008, and the RESOLVE{reg_sign} frequency domain portion was flown from June 29th to July 1st, 2008. Magnetic data were acquired contemporaneously with the electromagnetic surveys using a total-field cesium vapor magnetometer. Approximately 925 line kilometers (km) were flown using the HeliGEOTEM{reg_sign} II system and 412 line kilometers were flown using the RESOLVE{reg_sign} system. The HeliGEOTEM system has an effective penetration of roughly 250 meters into the ground and the RESOLVE system has an effective penetration of roughly 60 meters. Acquisition parameters and preliminary results are provided in SGW-39674, Airborne Electromagnetic Survey Report, 200-PO-1 Groundwater Operable Unit, 600 Area, Hanford Site. Airborne data are interpreted in this report in an attempt to identify areas of likely preferential groundwater flow within the aquifer system based on the presence of paleochannels or fault zones. The premise for the interpretation is that coarser-grained intervals have filled in scour channels created by episodic catastrophic flood events during the …
Date: November 11, 2010
Creator: GD, CUMMINS
Object Type: Report
System: The UNT Digital Library
Investigation of anti-Relaxation coatings for alkali-metal vapor cells using surface science techniques (open access)

Investigation of anti-Relaxation coatings for alkali-metal vapor cells using surface science techniques

Many technologies based on cells containing alkali-metal atomic vapor benefit from the use of antirelaxation surface coatings in order to preserve atomic spin polarization. In particular, paraffin has been used for this purpose for several decades and has been demonstrated to allow an atom to experience up to 10?000 collisions with the walls of its container without depolarizing, but the details of its operation remain poorly understood. We apply modern surface and bulk techniques to the study of paraffin coatings in order to characterize the properties that enable the effective preservation of alkali spin polarization. These methods include Fourier transform infrared spectroscopy, differential scanning calorimetry, atomic force microscopy, near-edge x-ray absorption fine structure spectroscopy, and x-ray photoelectron spectroscopy. We also compare the light-induced atomic desorption yields of several different paraffin materials. Experimental results include the determination that crystallinity of the coating material is unnecessary, and the detection of C=C double bonds present within a particular class of effective paraffin coatings. Further study should lead to the development of more robust paraffin antirelaxation coatings, as well as the design and synthesis of new classes of coating materials.
Date: October 11, 2010
Creator: Seltzer, S. J.; Michalak, D. J.; Donaldson, M. H.; Balabas, M. V.; Barber, S. K.; Bernasek, S. L. et al.
Object Type: Article
System: The UNT Digital Library
Kinetic Modeling of Gasoline Surrogate Components and Mixtures under Engine Conditions (open access)

Kinetic Modeling of Gasoline Surrogate Components and Mixtures under Engine Conditions

Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, an improved version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multicomponent gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines (3-50 atm, 650-1200K, stoichiometric fuel/air mixtures). Simulation results are discussed focusing attention on the mixing effects of the fuel components.
Date: January 11, 2010
Creator: Mehl, M; Pitz, W J; Westbrook, C K & Curran, H J
Object Type: Article
System: The UNT Digital Library
Lake Granbury and Lake Whitney Assessment Initiative Final Scientific/Technical Report Summary (open access)

Lake Granbury and Lake Whitney Assessment Initiative Final Scientific/Technical Report Summary

A team of Texas AgriLife Research, Baylor University and University of Texas at Arlington researchers studied the biology and ecology of Prymnesium parvum (golden algae) in Texas lakes using a three-fold approach that involved system-wide monitoring, experimentation at the microcosm and mesocosm scales, and mathematical modeling. The following are conclusions, to date, regarding this organism’s ecology and potential strategies for mitigation of blooms by this organism. In-lake monitoring revealed that golden algae are present throughout the year, even in lakes where blooms do not occur. Compilation of our field monitoring data with data collected by Texas Parks and Wildlife and Brazos River Authority (a period spanning a decade) revealed that inflow and salinity variables affect bloom formations. Thresholds for algae populations vary per lake, likely due to adaptations to local conditions, and also to variations in lake-basin morphometry, especially the presence of coves that may serve as hydraulic storage zones for P. parvum populations. More specifically, our in-lake monitoring showed that the highly toxic bloom that occurred in Lake Granbury in the winter of 2006/2007 was eliminated by increased river inflow events. The bloom was flushed from the system. The lower salinities that resulted contributed to golden algae not blooming …
Date: October 11, 2010
Creator: Harris, B.L.; Roelke, Daniel; Brooks, Bryan & Grover, James
Object Type: Report
System: The UNT Digital Library
Large Angular Jump Mechanism Observed for Hydrogen Bond Exchange in Aqueous Perchlorate Solution (open access)

Large Angular Jump Mechanism Observed for Hydrogen Bond Exchange in Aqueous Perchlorate Solution

The mechanism for hydrogen bond (H-bond) switching in solution has remained subject to debate despite extensive experimental and theoretical studies. We have applied polarization-selective multidimensional vibrational spectroscopy to investigate the H-bond exchange mechanism in aqueous NaClO{sub 4} solution. The results show that a water molecule shifts its donated H-bonds between water and perchlorate acceptors by means of large, prompt angular rotation. Using a jump-exchange kinetic model, we extract an average jump angle of 49 {+-} 4{sup o}, in qualitative agreement with the jump angle observed in molecular dynamics simulations of the same aqueous NaClO{sub 4} solution.
Date: June 11, 2010
Creator: Ji, Minbiao; /SLAC, PULSE /Stanford U., Phys. Dept.; Odelius3, Michael; U., /Stockholm; Gaffney1, K.J. & /aff SLAC, PULSE
Object Type: Article
System: The UNT Digital Library
Leptonic Decays of the Charged B Meson (open access)

Leptonic Decays of the Charged B Meson

The authors present a search for the decay B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}} ({ell} = {tau}, {mu}, or e) in (458.9 {+-} 5.1) x 10{sup 6} {Upsilon}(4S) decays recorded with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay (B{sup -} {yields} D{sup 0}{ell}{sup -}{bar {nu}}X) is selected, and in the recoil a search for B{sup +} {yields} {ell}{sup +}{nu}{sub {ell}} signal is performed. The {tau} is identified in the following channels: {tau}{sup +} {yields} e{sup +}{nu}{sub e}{bar {nu}}{sub {tau}}, {tau}{sup +} {yields} {mu}{sup +}{nu}{sub {mu}}{bar {nu}}{sub {tau}}, {tau}{sup +} {yields} {pi}{sup +}{bar {nu}}{sub {tau}}, and {tau}{sup +} {yields} {pi}{sup +}{pi}{sup 0}{bar {nu}}{sub {tau}}. The analysis strategy and the statistical procedure is set up for branching fraction extraction or upper limit determination. They determine from the dataset a preliminary measurement of {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) = (1.8 {+-} 0.8 {+-} 0.1) x 10{sup -4}, which excludes zero at 2.4{sigma}, and f{sub B} = 255 {+-} 58 MeV. Combination with the hadronically tagged measurement yields {Beta}(B{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) = (1.8 {+-} 0.6) x 10{sup -4}. They also set preliminary limits on the branching fractions at …
Date: June 11, 2010
Creator: Corwin, Luke A.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Life-Cycle Analysis Results of Geothermal Systems in Comparison to Other Power Systems. (open access)

Life-Cycle Analysis Results of Geothermal Systems in Comparison to Other Power Systems.

A life-cycle energy and greenhouse gas emissions analysis has been conducted with Argonne National Laboratory's expanded Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation (GREET) model for geothermal power-generating technologies, including enhanced geothermal, hydrothermal flash, and hydrothermal binary technologies. As a basis of comparison, a similar analysis has been conducted for other power-generating systems, including coal, natural gas combined cycle, nuclear, hydroelectric, wind, photovoltaic, and biomass by expanding the GREET model to include power plant construction for these latter systems with literature data. In this way, the GREET model has been expanded to include plant construction, as well as the usual fuel production and consumption stages of power plant life cycles. For the plant construction phase, on a per-megawatt (MW) output basis, conventional power plants in general are found to require less steel and concrete than renewable power systems. With the exception of the concrete requirements for gravity dam hydroelectric, enhanced geothermal and hydrothermal binary used more of these materials per MW than other renewable power-generation systems. Energy and greenhouse gas (GHG) ratios for the infrastructure and other life-cycle stages have also been developed in this study per kilowatt-hour (kWh) of electricity output by taking into account both plant …
Date: October 11, 2010
Creator: Sullivan, J. L.; Clark, C. E.; Han, J.; Wang, M. & Systems, Energy
Object Type: Report
System: The UNT Digital Library
Local Measurement of the Penetration Depth in the Pnictide Superconductor Ba(Fe_0.95 Co_0.05)_2 As_2 (open access)

Local Measurement of the Penetration Depth in the Pnictide Superconductor Ba(Fe_0.95 Co_0.05)_2 As_2

We use magnetic force microscopy (MFM) to measure the local penetration depth {lambda} in Ba(Fe{sub 0.95}Co{sub 0.05}){sub 2}As{sub 2} single crystals and use scanning SQUID susceptometry to measure its temperature variation down to 0.4 K. We observe that superfluid density {rho}{sub s} over the full temperature range is well described by a clean two-band fully gapped model. We demonstrate that MFM can measure the important and hard-to-determine absolute value of {lambda}, as well as obtain its temperature dependence and spatial homogeneity. We find {rho}{sub s} to be uniform on the submicron scale despite the highly disordered vortex pinning.
Date: January 11, 2010
Creator: Matsushita, Y.
Object Type: Article
System: The UNT Digital Library
Longitudinal Diagnostics for Short Electron Beam Bunches (open access)

Longitudinal Diagnostics for Short Electron Beam Bunches

Single-pass free electron lasers require high peak currents from ultra-short electron bunches to reach saturation and an accurate measurement of bunch length and longitudinal bunch profile is necessary to control the bunch compression process from low to high beam energy. The various state-of-the-art diagnostics methods from ps to fs time scales using coherent radiation detection, RF deflection, and other techniques are presented. The use of linear accelerators as drivers for free electron lasers (FEL) and the advent of single-pass (SASE) FELs has driven the development of a wide range of diagnostic techniques for measuring the length and longitudinal distribution of short and ultra-short electron bunches. For SASE FELs the radiation power and the length of the undulator needed to achieve saturation depend strongly on the charge density of the electron beam. In the case of X-ray FELs, this requires the accelerator to produce ultra-high brightness beams with micron size transverse normalized emittances and peak currents of several kA through several stages of magnetic bunch compression. Different longitudinal diagnostics are employed to measure the peak current and bunch profile along these stages. The measurement techniques can be distinguished into different classes. Coherent methods detect the light emitted from the beam by …
Date: June 11, 2010
Creator: Loos, H.
Object Type: Article
System: The UNT Digital Library
Low Prevalence of Chronic Beryllium Disease among Workers at a Nuclear Weapons Research and Development Facility (open access)

Low Prevalence of Chronic Beryllium Disease among Workers at a Nuclear Weapons Research and Development Facility

To study the prevalence of beryllium sensitization (BeS) and chronic beryllium disease (CBD) in a cohort of workers from a nuclear weapons research and development facility. We evaluated 50 workers with BeS with medical and occupational histories, physical examination, chest imaging with HRCT (N=49), and pulmonary function testing. Forty of these workers also underwent bronchoscopy for bronchoalveolar lavage (BAL) and transbronchial biopsies. The mean duration of employment at the facility was 18 yrs and the mean latency (from first possible exposure) to time of evaluation was 32 yrs. Five of the workers had CBD at the time of evaluation (based on histology or HRCT); three others had evidence of probable CBD. These workers with BeS, characterized by a long duration of potential Be exposure and a long latency, had a low prevalence of CBD.
Date: January 11, 2010
Creator: Arjomandi, M; Seward, J P; Gotway, M B; Nishimura, S; Fulton, G P; Thundiyil, J et al.
Object Type: Article
System: The UNT Digital Library
MANAGEMENT OF RESEARCH AND TEST REACTOR ALUMINUM SPENT NUCLEAR FUEL - A TECHNOLOGY ASSESSMENT (open access)

MANAGEMENT OF RESEARCH AND TEST REACTOR ALUMINUM SPENT NUCLEAR FUEL - A TECHNOLOGY ASSESSMENT

The Department of Energy's Environmental Management (DOE-EM) Program is responsible for the receipt and storage of aluminum research reactor spent nuclear fuel or used fuel until ultimate disposition. Aluminum research reactor used fuel is currently being stored or is anticipated to be returned to the U.S. and stored at DOE-EM storage facilities at the Savannah River Site and the Idaho Nuclear Technology and Engineering Center. This paper assesses the technologies and the options for safe transportation/receipt and interim storage of aluminum research reactor spent fuel and reviews the comprehensive strategy for its management. The U.S. Department of Energy uses the Appendix A, Spent Nuclear Fuel Acceptance Criteria, to identify the physical, chemical, and isotopic characteristics of spent nuclear fuel to be returned to the United States under the Foreign Research Reactor Spent Nuclear Fuel Acceptance Program. The fuel is further evaluated for acceptance through assessments of the fuel at the foreign sites that include corrosion damage and handleability. Transport involves use of commercial shipping casks with defined leakage rates that can provide containment of the fuel, some of which are breached. Options for safe storage include wet storage and dry storage. Both options must fully address potential degradation of the …
Date: July 11, 2010
Creator: Vinson, D.
Object Type: Article
System: The UNT Digital Library
Methodology Development and Applications of Proliferation Resistance and Physical Protection Evaluation. (open access)

Methodology Development and Applications of Proliferation Resistance and Physical Protection Evaluation.

We present an overview of the program on the evaluation methodology for proliferation resistance and physical protection (PR&PP) of advanced nuclear energy systems (NESs) sponsored by the Generation IV International Forum (GIF). For a proposed NES design, the methodology defines a set of challenges, analyzes system response to these challenges, and assesses outcomes. The challenges to the NES are the threats posed by potential actors (proliferant States or sub-national adversaries). The characteristics of Generation IV systems, both technical and institutional, are used to evaluate the response of the system and to determine its resistance against proliferation threats and robustness against sabotage and terrorism threats. The outcomes of the system response are expressed in terms of a set of measures, which are the high-level PR&PP characteristics of the NES. The methodology is organized to allow evaluations to be performed at the earliest stages of system design and to become more detailed and more representative as the design progresses. It can thus be used to enable a program in safeguards by design or to enhance the conceptual design process of an NES with regard to intrinsic features for PR&PP.
Date: April 11, 2010
Creator: Bari, R. A.; Peterson, P. F.; Whitlock, J. J. & Therios, I. U.
Object Type: Article
System: The UNT Digital Library
Modulation compression for short wavelength harmonic generation (open access)

Modulation compression for short wavelength harmonic generation

Laser modulator is used to seed free electron lasers. In this paper, we propose a scheme to compress the initial laser modulation in the longitudinal phase space by using two opposite sign bunch compressors and two opposite sign energy chirpers. This scheme could potentially reduce the initial modulation wavelength by a factor of C and increase the energy modulation amplitude by a factor of C, where C is the compression factor of the first bunch compressor. Such a compressed energy modulation can be directly used to generate short wavelength current modulation with a large bunching factor.
Date: January 11, 2010
Creator: Qiang, J.
Object Type: Article
System: The UNT Digital Library
Monte Carlo Simulation of the Prompt Dose Environment in the National Ignition Facility during Low Yield D-T Shots (open access)

Monte Carlo Simulation of the Prompt Dose Environment in the National Ignition Facility during Low Yield D-T Shots

None
Date: August 11, 2010
Creator: Khater, H Y & Brereton, S J
Object Type: Article
System: The UNT Digital Library
Nanoheterostructure Cation Exchange: Anionic Framework Conservation (open access)

Nanoheterostructure Cation Exchange: Anionic Framework Conservation

In ionic nanocrystals the cationic sub-lattice can be replaced with a different metal ion via a fast, simple, and reversible place-exchange, allowing post-synthetic modification of the composition of the nanocrystal, while preserving its size and shape. Here, we demonstrate for the first time that during such an exchange, the anionic framework of the crystal is preserved. When applied to nanoheterostructures, this phenomenon ensures that compositional interfaces within the heterostructure are conserved throughout the transformation. For instance, a morphology composed of a CdSe nanocrystal embedded in a CdS rod (CdSe/CdS) was exchanged to a PbSe/PbS nanorod via a Cu2Se/Cu2S structure. During every exchange cycle, the seed size and position within the nanorod were preserved, as evident by excitonic features, Z-contrast imaging, and elemental line-scans. Anionic framework conservation extends the domain of cation exchange to the design of more complex and unique nanostructures.
Date: May 11, 2010
Creator: Jain, Prashant K.; Amirav, Lilac; Aloni, Shaul & Alivisatos, A. Paul
Object Type: Article
System: The UNT Digital Library
National Emission Standards for Hazardous Air Pollutants - Radionuclide Emissions Calendar Year 2009 (open access)

National Emission Standards for Hazardous Air Pollutants - Radionuclide Emissions Calendar Year 2009

The U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office operates the Nevada Test Site (NTS) and North Las Vegas Facility (NLVF). From 1951 through 1992, the NTS was the continental testing location for U.S. nuclear weapons. The release of radionuclides from NTS activities has been monitored since the initiation of atmospheric testing. Limitation to underground detonations after 1962 greatly reduced radiation exposure to the public surrounding the NTS. After nuclear testing ended in 1992, NTS radiation monitoring focused on detecting airborne radionuclides from historically contaminated soils. These radionuclides are derived from re-suspension of soil (primarily by wind) and emission of tritium-contaminated soil moisture through evapotranspiration. Low amounts of tritium were also emitted to air at the NLVF, an NTS support complex in North Las Vegas. To protect the public from harmful levels of man-made radiation, the Clean Air Act, National Emission Standards for Hazardous Air Pollutants (NESHAP) (Title 40 Code of Federal Regulations [CFR] Part 61 Subpart H) limits the release of radioactivity from a U.S. Department of Energy facility to 10 millirem per year (mrem/yr) effective dose equivalent to any member of the public. This limit does not include radiation not related to NTS activities. Unrelated …
Date: June 11, 2010
Creator: Monitoring, NSTec Ecological and Environmental
Object Type: Report
System: The UNT Digital Library
New Fixed-Target Experiments to Search for Dark Gauge Forces (open access)

New Fixed-Target Experiments to Search for Dark Gauge Forces

Fixed-target experiments are ideally suited for discovering new MeV-GeV mass U(1) gauge bosons through their kinetic mixing with the photon. In this paper, we identify the production and decay properties of new light gauge bosons that dictate fixed-target search strategies. We summarize existing limits and suggest five new experimental approaches that we anticipate can cover most of the natural parameter space, using currently operating GeV-energy beams and well-established detection methods. Such experiments are particularly timely in light of recent terrestrial and astrophysical anomalies (PAMELA, FERMI, DAMA/LIBRA, etc.) consistent with dark matter charged under a new gauge force.
Date: June 11, 2010
Creator: Bjorken, James D.; Essig, Rouven; Schuster, Philip & Toro, Natalia
Object Type: Article
System: The UNT Digital Library
New Physics Search in the LHCb Era (open access)

New Physics Search in the LHCb Era

The authors present theoretical and experimental preparations for an indirect search for new physics (NP) using the rare decay {bar B}{sub d} {yields} {bar K}*{sup 0}{mu}{sup +}{mu}{sup -}. They design new observables with very small theoretical uncertainties and good experimental resolution.
Date: June 11, 2010
Creator: Hurth, Tobias
Object Type: Article
System: The UNT Digital Library