Resource Type

1,335 Matching Results

Results open in a new window/tab.

Multi-Objective Response to Co-Resident Attacks in Cloud Environment (open access)

Multi-Objective Response to Co-Resident Attacks in Cloud Environment

This article introduces a novel multi-objective attack response system.
Date: September 17, 2017
Creator: Abazari, Farzaneh; Analoui, Morteza & Takabi, Hassan
System: The UNT Digital Library
Ion Deflection for Final Optics In Laser Inertial Fusion Power Plants (open access)

Ion Deflection for Final Optics In Laser Inertial Fusion Power Plants

Left unprotected, both transmissive and reflective final optics in a laser inertial fusion power plant would quickly fail from melting, pulsed thermal stresses, or degradation of optical properties as a result of ion implantation. One potential option for mitigating this threat is to magnetically deflect the ions such that they are directed into a robust energy dump. In this paper we detail integrated studies that have been carried out to asses the viability of this approach for protecting final optics.
Date: November 17, 2006
Creator: Abbott, R P & Latkowski, J F
System: The UNT Digital Library
The On-Orbit Calibrations for the Fermi Large Area Telescope (open access)

The On-Orbit Calibrations for the Fermi Large Area Telescope

The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope began its on-orbit operations on June 23, 2008. Calibrations, defined in a generic sense, correspond to synchronization of trigger signals, optimization of delays for latching data, determination of detector thresholds, gains and responses, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and internal and spacecraft boresight alignments. Here we describe on-orbit calibration results obtained using known astrophysical sources, galactic cosmic rays, and charge injection into the front-end electronics of each detector. Instrument response functions will be described in a separate publication. This paper demonstrates the stability of calibrations and describes minor changes observed since launch. These results have been used to calibrate the LAT datasets to be publicly released in August 2009.
Date: November 17, 2011
Creator: Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. et al.
System: The UNT Digital Library
Pulsed Gamma-Rays From the Millisecond Pulsar J0030+0451 with the Fermi Large Area Telescope (open access)

Pulsed Gamma-Rays From the Millisecond Pulsar J0030+0451 with the Fermi Large Area Telescope

We report the discovery of gamma-ray pulsations from the nearby isolated millisecond pulsar PSR J0030+0451 with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope (formerly GLAST). This discovery makes PSR J0030+0451 the second millisecond pulsar to be detected in gamma-rays after PSR J0218+4232, observed by the EGRET instrument on the Compton Gamma Ray Observatory. The spin-down power {dot E} = 3.5 x 10{sup 33} ergs s{sup -1} is an order of magnitude lower than the empirical lower bound of previously known gamma-ray pulsars. The emission profile is characterized by two narrow peaks, respectively 0.07 {+-} 0.01 and 0.08 {+-} 0.02 wide, separated by 0.44 {+-} 0.02 in phase. The first gamma-ray peak falls 0.15 {+-} 0.01 after the main radio peak. The pulse shape is similar to that of the 'normal' gamma-ray pulsars. An exponentially cut-off power-law fit of the emission spectrum leads to an integral photon flux above 100 MeV of (6.76 {+-} 1.05 {+-} 1.35) x 10{sup -8} cm{sup -2} s{sup -1} with cut-off energy (1.7 {+-} 0.4 {+-} 0.5) GeV. Based on its parallax distance of (300 {+-} 90) pc, we obtain a gamma-ray efficiency L{sub {gamma}}/{dot E} {approx_equal} 15% for the conversion of …
Date: November 17, 2011
Creator: Abdo, Aous A.; /Naval Research Lab, Wash., D.C.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, W.B.; /UC, Santa Cruz et al.
System: The UNT Digital Library
Effect of Inert Gas Additive Species on Cl(2) High Density Plasma Etching of Compound Semiconductors: Part II. InP, InSb, InGaP and InGaAs (open access)

Effect of Inert Gas Additive Species on Cl(2) High Density Plasma Etching of Compound Semiconductors: Part II. InP, InSb, InGaP and InGaAs

The effects of the additive noble gases He, Ar and Xe on chlorine-based Inductively Coupled Plasma etching of InP, InSb, InGaP and InGaAs were studied as a function of source power, chuck power and discharge composition. The etch rates of all materials with C12/He and C12/Xe are greater than with C12/Ar. Etch rates in excess of 4.8 pndmin for InP and InSb with C12/He or C12/Xe, 0.9 pndmin for InGaP with C12/Xe, and 3.8 prdmin for InGaAs with Clz/Xe were obtained at 750 W ICP power, 250 W rf power, - 1570 C12 and 5 mTorr. All three plasma chemistries produced smooth morphologies for the etched InGaP surfaces, while the etched surface of InP showed rough morphology under all conditions.
Date: December 17, 1998
Creator: Abernathy, C.R.; Cho, H.; Hahn, Y.B.; Hays, D.C.; Jung, K.B.; Pearton, S.J. et al.
System: The UNT Digital Library
Forward Instrumentation for ILC Detectors (open access)

Forward Instrumentation for ILC Detectors

None
Date: June 17, 2013
Creator: Abramowicz, H.; Abusleme, A.; Afanaciev, K.; Aguilar, J.; Ambalathankandy, P.; Bambade, P. et al.
System: The UNT Digital Library
Theory of high-T{sub c} cuprates based on experimental evidence. (open access)

Theory of high-T{sub c} cuprates based on experimental evidence.

A model of superconductivity in layered high-temperature superconducting cuprates is proposed, based on the extended saddle point singularities in the electron spectrum, weak screening of the Coulomb interaction and phonon-mediated interaction between electrons plus a small short-range repulsion of Hund's, or spin-fluctuation, origin. This permits to explain the large values of T{sub c}, features of the isotope effect on oxygen and copper, the existence of two types of the order parameter, the peak in the inelastic neutron scattering, the positive curvature of the upper critical field, as function of temperature etc.
Date: August 17, 1999
Creator: Abrikosov, A. A.
System: The UNT Digital Library
Operation of a Free-Electron Laser from the Extreme Ultraviolet to the Water Window (open access)

Operation of a Free-Electron Laser from the Extreme Ultraviolet to the Water Window

We report results on the performance of a free-electron laser operating at a wavelength of 13.7 nm where unprecedented peak and average powers for a coherent extreme-ultraviolet radiation source have been measured. In the saturation regime, the peak energy approached 170 {micro}J for individual pulses, and the average energy per pulse reached 70 {micro}J. The pulse duration was in the region of 10 fs, and peak powers of 10 GW were achieved. At a pulse repetition frequency of 700 pulses per second, the average extreme-ultraviolet power reached 20mW. The output beam also contained a significant contribution from odd harmonics of approximately 0.6% and 0.03% for the 3rd (4.6 nm) and the 5th (2.75 nm) harmonics, respectively. At 2.75 nm the 5th harmonic of the radiation reaches deep into the water window, a wavelength range that is crucially important for the investigation of biological samples.
Date: December 17, 2007
Creator: Ackermann, W.; Asova, G.; Ayvazyan, V.; Azima, A.; Baboi, N.; Bahr, J. et al.
System: The UNT Digital Library
Commentary on “Experimental Measurements and Equilibrium Study of Functional D-Sorbitol in Good and Anti-Solvent Binary Mixtures” (open access)

Commentary on “Experimental Measurements and Equilibrium Study of Functional D-Sorbitol in Good and Anti-Solvent Binary Mixtures”

This article provides a commentary on the published equation coefficients for mathematically describing the solubility behavior of D-sorbitol in binary acetonitrile + ethanol solvent mixtures using the modified Apelblat, Combined Nearly Ideal Binary Solvent/Redlich-Kister (CNIBS/R-K) and Jouyban-Acree models.
Date: June 17, 2017
Creator: Acree, William E. (William Eugene)
System: The UNT Digital Library

Commentary on "Solubility and solution thermodynamics of cetilistat in water and (acetone, isopropyl alcohol, acetonitrile) binary solvent mixtures"

This article reanalyzes experimental solubility data reported in the recent paper "Solubility and solution thermodynamics of cetilistat in water and (acetone, isopropyl alcohol, acetonitrile) binary solvent mixtures" in the Journal of Molecular Liquids.
Date: January 17, 2017
Creator: Acree, William E. (William Eugene)
System: The UNT Digital Library
Phase Change Enthalpies and Entropies of Liquid Crystals (open access)

Phase Change Enthalpies and Entropies of Liquid Crystals

Article on phase change enthalpies and entropies of liquid crystals.
Date: July 17, 2006
Creator: Acree, William E. (William Eugene) & Chickos, James S.
System: The UNT Digital Library
Wind Resource Development Project for Armenia (open access)

Wind Resource Development Project for Armenia

Armenia has few proven reserves of natural energy and is dependent on long, unreliable transport lines for oil and gas. Preliminary studies indicate that the wind energy potential in Armenia is more than 500 megawatts (MW), assuming a reasonable fraction of 10% of the land area in the high-wind zones. Over the long term, the Armenian government intends to meet 8%--10% of its electric consumption needs by grid-connected wind turbines. The goals of this project are to enhance Armenia's energy security, mitigate the environmental damage of conventional sources of energy, reduce future carbon dioxide emissions, build an environmentally sound and sustainable model for economic development, and promote trade between the U.S. and Armenia. The project is being funded by the Cafesjian Family Foundation, a private foundation based in the United States in Naples, Florida, with the participation of Ecotrade, Inc. of Glendale, California. The National Renewable Energy Laboratory (NREL) is providing technical assistance. As part of the wind energy development project, the authors conducted a preliminary wind-energy resource assessment for some regions in Armenia. This activity provided valuable information needed to facilitate the commercialization of wind farms in Armenia and to lay the groundwork for subsequent wind resource activities. This …
Date: August 17, 2000
Creator: Adamian, S.; Manoukian, L.; Lalayan, A. & Gevorgian, V. (National Renewable Energy Laboratory)
System: The UNT Digital Library
Characterization of Corrosion Products from Static Cell Testing of Al-SNF Forms (open access)

Characterization of Corrosion Products from Static Cell Testing of Al-SNF Forms

Aluminum-based spent nuclear fuel from foreign and domestic research reactors is being consolidated at the Savannah River Site (SRS) for ultimate disposal in the Monitored Geologic Repository. The melt-dilute treatment technology has been developed to consolidate fuel assemblies by a melting/casting process in which depleted uranium is added to reduce enrichment below 20 percent 235-U. The melt-dilute product is essentially a binary uranium-aluminum alloy to which neutron absorber materials may be readily added.
Date: September 17, 2002
Creator: Adams, T.
System: The UNT Digital Library
Off-Gas System Development for the Melt-Dilute Treatment of Aluminum-Based Spent Nuclear Fuel (open access)

Off-Gas System Development for the Melt-Dilute Treatment of Aluminum-Based Spent Nuclear Fuel

This effort will provide a technical basis to assure safe and efficient system operation of the melt-dilute process and have general applicability to off-gas streams.
Date: September 17, 2002
Creator: Adams, T.
System: The UNT Digital Library
Treatment of Legacy Materials Using the Melt-Dilute Treatment Technology (open access)

Treatment of Legacy Materials Using the Melt-Dilute Treatment Technology

This paper reviews the candidate legacy materials and addresses adaptation of the melt-dilute technology to treat DOE legacy waste streams.
Date: September 17, 2002
Creator: Adams, T.
System: The UNT Digital Library
Evaluation of Oxidation and Hydrogen Permeation of Al Containing Duplex Stainless Steels (open access)

Evaluation of Oxidation and Hydrogen Permeation of Al Containing Duplex Stainless Steels

As the National Hydrogen Economy continues to develop and evolve the need for structural materials that can resist hydrogen assisted degradation will become critical. To date austenitic stainless steel materials have been shown to be mildly susceptible to hydrogen attack which results in lower mechanical and fracture strengths. As a result, hydrogen permeation barrier coatings are typically applied to these steel to retard hydrogen ingress. The focal point of the reported work was to evaluate the potential for intentional alloying of commercial 300-series stainless steels to promote hydrogen permeation resistant oxide scales. Previous research on the Cr- and Fe-oxide scales inherent to 300-series stainless steels has proven to be inconsistent in effecting permeation resistance. The approach undertaken in this research was to add aluminum to the 300-series stainless steels in an attempt to promote a pure Al-oxide or and Al-rich oxide scale. Aloxide had been previously demonstrated to be an effective hydrogen permeation barrier. Results for 304L and 347H alloys doped with Al in concentration from 0.5-3.0 wt% with respect to oxidation kinetic studies, cyclic oxidation and characterization of the oxide scale chemistry are reported herein. Gaseous hydrogen permeation testing of the Al-doped alloys in both the unoxidized and oxidized …
Date: June 17, 2005
Creator: Adams, Thad M.; Korinko, Paul & Duncan, Andrew
System: The UNT Digital Library
PdMn and PdFe: New Materials for Temperature Measurement Near 2K (open access)

PdMn and PdFe: New Materials for Temperature Measurement Near 2K

Interest in the critical dynamics of superfluid <SUP>4</SUP> He in microgravity conditions has motivated the development of new high resolution thermometry technol- ogy for use in space experiments near 2K. The current material commonly used as the temperature sensing element for high resolution thermometers (HRTs) is copper ammonium bromide [Cu(NH<SUB>4</SUB>)<SUB>2</SUB>Br<SUB>4</SUB>2H<SUB>2</SUB>0) or "CAB", which undergoes a ferromagnetic phase transition at 1.8K1. HRTs made from CAB have demonstrated low drift (< 10fK/s) and a temperature resolu- tion of O.lnK. Unfortunately, paramagnetic salts such as CAB are difficult to prepare and handle, corrosive to most metals, and become dehydrated if kept, under vacuum conditions at room temperature. We have developed a magnetic thermometer using dilute magnetic alloys of Mn or Fe dissolved in a pure Pd matrix. These metallic thermometers are easy to fabricate, chemically inert, and mechanically robust. Unlike salts, they may be directly soldered to the stage to be measured. Also, the Curie temperature can be varied by changing the concentration of Fe or Mn, making them available for use in a wide temperature range. Susceptibility measurements, as well as preliminary noise and drifl measurements, show them, to have sub-nK resolution, with a drift of less than 10<SUP>-13</SUP> K/s.
Date: May 17, 1999
Creator: Adriaans, M. J.; Aselage, T. L.; Day, P. K.; Duncan, R. V.; Klemme, B. J. & Sergatskov, D. A.
System: The UNT Digital Library
Phase Behavior of Blends of Linear and Branched Polyethylenes on Micron-Length Scales via Ultra-Small-Angle Neutron Scattering (USANS) (open access)

Phase Behavior of Blends of Linear and Branched Polyethylenes on Micron-Length Scales via Ultra-Small-Angle Neutron Scattering (USANS)

SANS experiments on blends of linear, high density (HD) and long chain branched, low density (LD) polyethylenes indicate that these systems form a one-phase mixture in the melt. However, the maximum spatial resolution of pinhole cameras is approximately equal to 10<sup>3</sup>Å and it has therefore been suggested that data might also be interpreted as arising from a bi-phasic melt with large a particle size (~ 1 µm), because most of the scattering from the different phases would not be resolved. We have addressed this hypothesis by means of USANS experiments, which confirm that HDPEILDPE blends are homogenous in the melt on length scales up to 20 µm. We have also studied blends of HDPE and short-chain branched linear low density polyethylenes (LLDPEs), which phase separate when the branch content is sufficiently high. LLDPEs prepared with Ziegler-Natta catalysts exhibit a wide distribution of compositions, and may therefore be thought of as a �blend� of different species. When the composition distribution is broad enough, a fraction of highly branched chains may phase separate on µm-length scales, and USANS has also been used to quantify this phenomenon.
Date: May 17, 1999
Creator: Agamalian, M. M.; Alamo, R. G.; Londono, J. D.; Mandelkern, L. & Wignall, G. D.
System: The UNT Digital Library
Phase Behavior of Blends of Linear and Branched Polyethylenes via Small- and Ultra-Small Angle Neutron Scattering (open access)

Phase Behavior of Blends of Linear and Branched Polyethylenes via Small- and Ultra-Small Angle Neutron Scattering

None
Date: May 17, 1999
Creator: Agamalian, M. M.; Alamo, R. G.; Londono, J. D.; Mandelkern, L.; Stehling, F. C. & Wignall, G. D.
System: The UNT Digital Library
High-purity, isotopically enriched bulk silicon (open access)

High-purity, isotopically enriched bulk silicon

The synthesis and characterization of dislocation-free, undoped, single crystals of Si enriched in all 3 stable isotopes is reported: {sup 28}Si (99.92%), {sup 29}Si (91.37%), and {sup 30}Si (89.8%). A silane-based process compatible with the relatively small amounts of isotopically enriched precursors that are practically available was used. The silane is decomposed to silicon on a graphite starter rod heated to 700-750 C in a recirculating flow reactor. A typical run produces 35 gm of polycrystalline Si at a growth rates of 5 {micro}m/min and conversion efficiency &gt;95%. Single crystals are grown by the floating zone method and characterized by electrical and optical measurements. Concentrations of shallow dopants (P and B) are as low as mid-10{sup 13} cm{sup -3}. Concentrations of C and O lie below 10{sup 16} and 10{sup 15} cm{sup -3}, respectively.
Date: November 17, 2004
Creator: Ager, J. W., III; Beeman, J. W.; Hansen, W. L.; Haller, E. E.; Sharp, I. D.; Liao, C. et al.
System: The UNT Digital Library
Normal Conducting Radio Frequency X-Band Deflecting Cavity Fabrication and Validation (open access)

Normal Conducting Radio Frequency X-Band Deflecting Cavity Fabrication and Validation

None
Date: October 17, 2013
Creator: Agustsson, R.; Faillace, L.; Murokh, A.; Storms, S.; Rosenzweig, J.; Alesini, D. et al.
System: The UNT Digital Library
Global Security, Medical Isotopes, and Nuclear Science (open access)

Global Security, Medical Isotopes, and Nuclear Science

Over the past century basic nuclear science research has led to the use of radioactive isotopes into a wide variety of applications that touch our lives everyday. Some are obvious, such as isotopes for medical diagnostics and treatment. Others are less so, such as National/Global security issues. And some we take for granted, like the small amount of 241Am that is in every smoke detector. At the beginning of this century, we are in a position where the prevalence and importance of some applications of nuclear science are pushing the basic nuclear science community for improved models and nuclear data. Yet, at the same time, the push by the basic nuclear science community to study nuclei that are farther and farther away from stability also offer new opportunities for many applications. This talk will look at several global security applications of nuclear science, summarizing current R&amp;D and need for improved nuclear data It will also look at how applications of nuclear science, such as to medicine, will benefit from the push for more and more powerful radioactive ion beam facilities.
Date: September 17, 2007
Creator: Ahle, L. E.
System: The UNT Digital Library