117 Matching Results

Search Results

Results: 1 - 24 next
open access

The soudan 2 experiment

Description: Soudan 2 is an 1100-ton tracking calorimeter which is being constructed to search for nucleon decay. The detector consists of finely segmented iron instrumented with drift tubes, and records three spatial coordinates and dE/dx for every gas crossing. Excellent event-reconstruction capability, particle identification, and muon sign and direction determination give superior rejection of the neutrino background to nucleon decay in many modes. The first 275 tons of Soudan 2 is operating and a charg… more
Date: May 25, 1989
Creator: Ayres, D.S.
Partner: UNT Libraries Government Documents Department
open access

Preparation and Reactions of Base-FreeBis(1,2,4-tri-tert-butylcyclopentadienyl)uranium Oxide, Cp'2UO

Description: Reduction of the uranium metallocene,[eta5-1,2,4-(Me3C)3C5H2]2UCl2 (1), Cp'2UCl2, in the presence of2,2'-bipyridyl and sodium naphthalene gives the dark green metallocenecomplex, Cp'2U(bipy) (6), which reacts with p-tolylazide orpyridine-N-oxide to give Cp'2U=N(p-tolyl) (7) or Cp'2U(O)(py) (8),respectively. The Lewis acid, BPh3, precipitates Ph3B(py) and gives thebase-free oxo, Cp'2UO (10), which crystallizes from pentane. Theoxometallocene 10 behaves as a nucleophile with Me3SiX reagents but i… more
Date: May 25, 2005
Creator: Zi, Guofu; Werkema, Evan L.; Walter, Marc D.; Gottfriedsen,Jochen P. & Andersen, Richard A.
Partner: UNT Libraries Government Documents Department
open access

An analytical solution for transient gas flow in a multi-wellsystem

Description: Soil vapor extraction (SVE) combined with air injectionprovides an efficient way for the cleanup of vadose zone contaminated byvolatile organic chemicals (VOCs). A successful design of an SVE system,however, relies on a good knowledge of the induced gas flow field in thevadose zone. Analytical solutions are available to help understand thegas flow field at steady-state. However, most SVE systems must pass atransient period before reaching steady (or quasi-steady) state and thelength of the peri… more
Date: May 25, 2006
Creator: Shan, Chao
Partner: UNT Libraries Government Documents Department
open access

Radiochemical Solar Neutrino Experiments - Successful and Otherwise.

Description: Over the years, several different radiochemical systems have been proposed as solar neutrino detectors. Of these, two achieved operating status and obtained important results that helped to define the current field of neutrino physics: the first solar-neutrino experiment, the Chlorine Detector ({sup 37}Cl) that was developed by chemist Raymond Davis and colleagues at the Homestake Mine, and the subsequent Gallium ({sup 71}Ga) Detectors that were operated by (a) the SAGE collaboration at the Bak… more
Date: May 25, 2008
Creator: Hahn,R.L.
Partner: UNT Libraries Government Documents Department
open access

Symmetry Breaking in Few Layer Graphene Films

Description: Recently, it was demonstrated that the quasiparticledynamics, the layer-dependent charge and potential, and the c-axisscreening coefficient could be extracted from measurements of thespectral function of few layer graphene films grown epitaxially on SiCusing angle-resolved photoemission spectroscopy (ARPES). In this articlewe review these findings, and present detailed methodology for extractingsuch parameters from ARPES. We also present detailed arguments againstthe possibility of an energy ga… more
Date: May 25, 2007
Creator: Bostwick, A.; Ohta, T.; McChesney, J.L.; Emtsev, K.; Seyller,Th.; Horn, K. et al.
Partner: UNT Libraries Government Documents Department
open access

Structural analysis of flexible proteins in solution by SmallAngle X-ray Scattering combined with crystallography

Description: In the last few years, SAXS of biological materials has been rapidly evolving and promises to move structural analysis to a new level. Recent innovations in SAXS data analysis allow ab initio shape predictions of proteins in solution. Furthermore, experimental scattering data can be compared to calculated scattering curves from the growing data base of solved structures and also identify aggregation and unfolded proteins. Combining SAXS results with atomic resolution structures enables detailed… more
Date: May 25, 2006
Creator: Tsutakawa, Susan E.; Hura, Greg L.; Frankel, Ken A.; Cooper,Priscilla K. & Tainer, John A.
Partner: UNT Libraries Government Documents Department
open access

Radiation-effects limits on copper in superconducting magnets

Description: The determination of the response of copper stabilizers to neutron irradiation in fusion-reactor superconducting magnets requires information in four areas: (1) neutron flux and spectrum determination, (2) resistivity changes at zero field, (3) resistivity changes at field, and (4) the cyclic irradiation and annealing. Applications of our current understanding of the limits of copper stabilizers in fusion-reactor designs are explored in two examples. Recommendations for future additions to the … more
Date: May 25, 1983
Creator: Guinan, M.W.
Partner: UNT Libraries Government Documents Department
open access

Pulse power for the RAPIER B Amplifier KrF laser system

Description: The RAPIER B Amplifier electron beam system has been completed and produces 36kJ of 450 keV electrons in a 150 ns pulse to be used for pumping a KrF laser amplifier. The operating characteristics of the system have been studied. The efficiency of conversion of energy stored in the Marx generator to electron beam output is 72 +- 3% including an 89% designed transfer efficiency. The system is triggered electrically with a 150 ns delay from the command trigger to machine output. The rms jitter for… more
Date: May 25, 1983
Creator: Schlitt, L. G.
Partner: UNT Libraries Government Documents Department
open access

Soudan 2 as a long baseline neutrino detector

Description: In a nine month run with a 150 GeV proton beam and a conventional double horn neutrino beam aimed at the Soudan 2 detector, a search could be made for neutrino oscillations in the mode /nu//sub /mu// /yields/ /nu//sub /tau//. If evidence for oscillations is not found, new limits could be set extending the /Delta/m/sup 2/ excluded region from .3 eV/sup 2/ to .004 eV/sup 2/ at 90% confidence level. 7 refs., 4 figs.
Date: May 25, 1989
Creator: Goodman, M.
Partner: UNT Libraries Government Documents Department
open access

Models of optical and soft x-ray spectra in AM Her stars

Description: The AM Her systems are widely believed to be cataclysmic variable systems in which the white dwarf has a magnetic field strong enough to lock the white dwarf to the companion star. The magnetic field channels the accretion flow to the magnetic polar caps of the white dwarf where the gas passes through a strong shock and the accretion energy is released. The continuum spectra of the AM Her systems have three major components: the ir/optical component, the EUV/soft x-ray component, and the hard x… more
Date: May 25, 1987
Creator: Langer, S.H.
Partner: UNT Libraries Government Documents Department
open access

A pipelined IC architecture for radon transform computations in a multiprocessor array

Description: The amount of data generated by CT scanners is enormous, making the reconstruction operation slow, especially for 3-D and limited-data scans requiring iterative algorithms. The Radon transform and its inverse, commonly used for CT image reconstruction from projections, are computationally burdensome for today's single-processor computer architectures. If the processing times for the forward and inverse Radon transforms were comparatively small, a large set of new CT algorithms would become feas… more
Date: May 25, 1990
Creator: Agi, I.; Hurst, P.J. & Current, K.W. (California Univ., Davis, CA (USA). Dept. of Electrical Engineering and Computer Science)
Partner: UNT Libraries Government Documents Department
open access

Workshop on heavy ion physics at the AGS: Outlook

Description: This report presents the closing talk of the workshop on AGS heavy ion program held at BNL March 5--7, 1990. The emphasis is on new questions posed by the new data presented at this meeting with emphasis on the pion-proton puzzle. 10 refs., 1 fig., 1 tab.
Date: May 25, 1990
Creator: Gyulassy, M.
Partner: UNT Libraries Government Documents Department
open access

Carbon Nanotube-Based Permeable Membranes: A Platform for Studying Nanofluidics

Description: A membrane of multiwalled carbon nanotubes embedded in a silicon nitride matrix was fabricated for use in studying fluid mechanics on the nanometer scale. Characterization by fluorescent tracer diffusion and scanning electron microscopy suggests that the membrane is void-free near the silicon substrate on which it rests, implying that the hollow core of the nanotube is the only conduction path for molecular transport. Nitrogen flow measurements of a nanoporous silicon nitride membrane, fabricat… more
Date: May 25, 2004
Creator: Holt, J K; Park, H G; Noy, A; Huser, T; Eaglesham, D & Bakajin, O
Partner: UNT Libraries Government Documents Department
open access

Real-time Studies of Shocked Polycrystalline Materials with Single-Pulse X-ray Diffraction

Description: Characteristic K-α x-rays used for single-pulse XRD are conventionally produced by a 37-stage high-voltage Marx pulse generator coupled to a vacuum needle-and-washer x-ray diode via coaxial transmission line. A large field-of-view x-ray image plate detection system typically enables observation of several Debye-Scherrer rings. Recently, we have developed a fiber-optic reducer, coupled to a CCD camera, to obtain low-noise, large field-of-view images. The direct beam spot is produced by bremsstra… more
Date: May 25, 2011
Creator: Morgan, Dane V.
Partner: UNT Libraries Government Documents Department
open access

Synthesis of Accretion Disk and Nonthermal Source Models for AGN

Description: A scenario for the central engine of AGN has been developed consisting of a massive black hole (MBH) onto which gas accretes through an accretion disk. The accretion disk radiates the observed optical and ultraviolet continua. Surrounding the MBH is a nonthermal source which produces the infrared and soft x-ray continua by synchrotron emission, and the x-ray spectrum by inverse Compton scattering of the optical-ultraviolet photons from the accretion disk. Previously we modeled the accretion dis… more
Date: May 25, 1988
Creator: Band, D. L. & Malkan, M. A.
Partner: UNT Libraries Government Documents Department
open access

SPS Ecloud Instabilities - Analysis of Machine Studies and Implications for Ecloud Feedback

Description: The SPS at high intensities exhibits transverse single bunch instabilities with signatures consistent with an Ecloud driven instability. We present recent MD data from the SPS, details of the instrument technique and spectral analysis methods which help reveal complex vertical motion that develops within a subset of the injected bunch trains. The beam motion is detected via wideband exponential taper striplines and delta-sigma hybrids. The raw sum and difference data is sampled at 50 GHz with 1… more
Date: May 25, 2011
Creator: Fox, J.; Bullitt, A.; Mastorides, T.; Ndabashimiye, G.; Rivetta, C. H.; Turgut, O. et al.
Partner: UNT Libraries Government Documents Department
open access

Environmental considerations and regulations

Description: Methods used to control the radiological impact of the nuclear fuel cycle are described. This control is exercised through the application of a series of federal laws and regulations that are used as the basis for licensing nuclear facilities. The control is exercised more directly by the use of radwaste treatment equipment at the nuclear facilities to limit the release of radioactive materials. Federal laws and regulations are summarized and their applications in licensing actions are discusse… more
Date: May 25, 1976
Creator: Blanco, R. E.
Partner: UNT Libraries Government Documents Department
open access

Photodiode-Based X-Ray Beam-Position Monitor With High Spatial-Resolution for the NSLS-II Beamlines

Description: We developed a photodiode-based monochromatic X-ray beam-position monitor (X-BPM) with high spatial resolution for the project beamlines of the NSLS-II. A ring array of 32 Si PIN-junction photodiodes were designed for use as a position sensor, and a low-noise HERMES4 ASIC chip was integrated into the electronic readout system. A series of precision measurements to characterize electrically the Si-photodiode sensor and the ASIC chip demonstrated that the inherent noise is sufficiently below tole… more
Date: May 25, 2009
Creator: Yoon, P.S. & Siddons, D. P.
Partner: UNT Libraries Government Documents Department
open access

Correlation method for the measure of mask-induced line-edge roughness in extreme ultraviolet lithography

Description: As critical dimensions for leading-edge semiconductor devices shrink, line-edge roughness (LER) requirements are pushing well into the single digit nanometer regime. At these scales many new sources of LER must be considered. In the case of extreme ultraviolet (EUV) lithography, modeling has shown the lithographic mask to be a source of significant concern. Here we present a correlation-based methodology for experimentally measuring the magnitude of mask contributors to printed LER. The method … more
Date: May 25, 2009
Creator: Naulleau, Patrick
Partner: UNT Libraries Government Documents Department
open access

30th Actinide Separations Conference, PNNL-SA-50126

Description: Program booklet for the 30th Actinide Separations Conference. Contains agenda and abstracts for 27 poster and 38 oral presentations to be made during the 3-day meeting, May 23-25, 2006.
Date: May 25, 2006
Creator: Delegard, Calvin H.
Partner: UNT Libraries Government Documents Department
open access

EVENT TREE ANALYSIS AT THE SAVANNAH RIVER SITE: A CASE HISTORY

Description: At the Savannah River Site (SRS), a Department of Energy (DOE) installation in west-central South Carolina there is a unique geologic stratum that exists at depth that has the potential to cause surface settlement resulting from a seismic event. In the past the particular stratum in question has been remediated via pressure grouting, however the benefits of remediation have always been debatable. Recently the SRS has attempted to frame the issue in terms of risk via an event tree or logic tree … more
Date: May 25, 2009
Creator: Williams, R
Partner: UNT Libraries Government Documents Department
open access

Collins Mechanism Contributions to Single Spin Asymmetry

Description: We present recent developments on the single transverse spin physics, in particular, the Collins mechanism contributions in various hadronic reactions, such as semi-inclusive hadron production in DIS process, azimuthal distribution of hadron in high energy jet in pp collisions. We will demonstrate that the transverse momentum dependent and collinear factorization approaches are consistent with each other in the description of the Collins effects in the semi-inclusive hadron production in DIS pr… more
Date: May 25, 2009
Creator: Yuan,F.
Partner: UNT Libraries Government Documents Department
open access

Performance of exponential coupler in the SPS with LHC type beam for transverse broadband instability analysis

Description: We present the performance and limitations of the SPS exponential coupler [1] for transverse instability measurements with LHC type beam. Data were acquired in 2008 in the SPS in the time domain with a bandwidth of up to 2.5 GHz. The data were filtered to extract the time evolution of transverse oscillations within the less than 5 ns long LHC type bunches. We describe the data filtering techniques and show the limitations of the pick-up due to propagating modes.
Date: May 25, 2009
Creator: De Maria, R.; Fox, J. D.; Hofle, W.; Kotzian, G.; Rumolo, G.; Salvant, B. et al.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen