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First-principles investigations of the dielectric properties of polypropylene/metal-oxide interfaces

Description: Article on first-principles investigations of the dielectric properties of polypropylene/metal-oxide interfaces. Nanoscale-resolved dielectric properties of polypropylene/metal-oxide (alumina, PbTiO₃) interfaces and of the corresponding surfaces are investigated via first-principles calculations.
Date: October 30, 2009
Creator: Yu, Liping; Ranjan, Vivek; Buongiorno Nardelli, Marco & Bernholc, Jerry
Partner: UNT College of Arts and Sciences
open access

Using SPARK as a Solver for Modelica

Description: Modelica is an object-oriented acausal modeling language that is well positioned to become a de-facto standard for expressing models of complex physical systems. To simulate a model expressed in Modelica, it needs to be translated into executable code. For generating run-time efficient code, such a translation needs to employ algebraic formula manipulations. As the SPARK solver has been shown to be competitive for generating such code but currently cannot be used with the Modelica language, we … more
Date: June 30, 2008
Creator: Wetter, Michael; Wetter, Michael; Haves, Philip; Moshier, Michael A. & Sowell, Edward F.
Partner: UNT Libraries Government Documents Department
open access

Multi-Megajoule NIF: Ushering In a New Era in High Energy Density Science

Description: This paper describes the status of the stadium-sized National Ignition Facility (NIF), the world's largest laser system and first operational multi-megajoule laser. The 192-beam NIF, located at Lawrence Livermore National Laboratory (LLNL), is 96% complete and scheduled for completion in March 2009. The NIF laser will produce nanosecond laser pulses with energies up to approximately 4 MJ in the infrared (laser wavelength = 1.053-{micro}m) and 2MJ in the ultraviolet (laser wavelength = 0.35-{mic… more
Date: April 30, 2008
Creator: Keane, C & Moses, E I
Partner: UNT Libraries Government Documents Department
open access

Shot-Noise Seeded Microbunching Instability: Second-Order Correction to the Gain Function

Description: We determine the second-order correction to the gain function of the microbunching instability in single-pass systems of interest for the next generation of light sources. The calculation applies to the case where the instability is seeded by shot noise. We examine an analytically treatable model of beam dynamics where collective forces are active only in non-dispersive sections of the linac. We find that the second order term can augment the linear gain significantly while affecting the spectr… more
Date: June 30, 2008
Creator: Venturini, Marco
Partner: UNT Libraries Government Documents Department
open access

Discovery of A Very Bright, Strongly-Lensed z=2 Galaxy in the SDSS DR5

Description: We report on the discovery of a very bright z = 2.00 star-forming galaxy that is strongly lensed by a foreground z = 0.422 luminous red galaxy (LRG). This system was found in a systematic search for bright arcs lensed by LRGs and brightest cluster galaxies in the Sloan Digital Sky Survey Data Release 5 sample. Follow-up observations on the Subaru 8.2m telescope on Mauna Kea and the Astrophysical Research Consortium 3.5m telescope at Apache Point Observatory confirmed the lensing nature of this … more
Date: September 30, 2008
Creator: Lin, Huan; Buckley-Geer, Elizabeth; Allam, Sahar S.; Tucker, Douglas L.; Diehl, H.Thomas; Kubik, Donna et al.
Partner: UNT Libraries Government Documents Department
open access

World Sheet Commuting beta-gamma CFT and Non-Relativistic StringTheories

Description: We construct a sigma model in two dimensions with Galilean symmetry in flat target space similar to the sigma model of the critical string theory with Lorentz symmetry in 10 flat spacetime dimensions. This is motivated by the works of Gomis and Ooguri[1] and Danielsson et. al.[2, 3]. Our theory is much simpler than their theory and does not assume a compact coordinate. This non-relativistic string theory has a bosonic matter {beta}{gamma} CFT with the conformal weight of {beta} as 1. It is natu… more
Date: August 30, 2007
Creator: Kim, Bom Soo
Partner: UNT Libraries Government Documents Department
open access

Overview of the National Ignition Facility

Description: The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory will be the world's largest and most powerful laser system for inertial confinement fusion (ICF) and experiments studying high energy density (HED) science. NIF is a 192 beam Nd-glass laser facility that will produce 1.8 MJ, 500 TW of ultraviolet light making it over fifty times more energetic than present ICF facilities. The NIF Project began in 1995 and is scheduled for completion in 2009. Ignition experiments on N… more
Date: August 30, 2007
Creator: Moses, Edward
Partner: UNT Libraries Government Documents Department
open access

TiO2 Nanoparticles as a Soft X-ray Molecular Probe

Description: With the emergence of soft x-ray techniques for imaging cells, there is a pressing need to develop protein localization probes that can be unambiguously identified within the region of x-ray spectrum used for imaging. TiO2 nanocrystal colloids, which have a strong absorption cross-section within the "water-window" region of x-rays, areideally suited as soft x-ray microscopy probes. To demonstrate their efficacy, TiO2-streptavidin nanoconjugates were prepared and subsequently labeled microtubule… more
Date: June 30, 2007
Creator: Larabell, Carolyn; Ashcroft, Jared M.; Gu, Weiwei; Zhang, Tierui; Hughes, Steven M.; Hartman, Keith B. et al.
Partner: UNT Libraries Government Documents Department
open access

SPENT NUCLEAR FUEL STORAGE BASIN WATER CHEMISTRY: ELECTROCHEMICAL EVALUATION OF ALUMINUM CORROSION

Description: The factors affecting the optimal water chemistry of the Savannah River Site spent fuel storage basin must be determines in order to optimize facility efficiency, minimize fuel corrosion, and reduce overall environmental impact from long term spent nuclear fuel storage at the Savannah River Site. The Savannah River National Laboratory is using statistically designed experiments to study the effects of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, and Cl{sup -} concentrations on alloys commonly used not … more
Date: October 30, 2007
Creator: Hathcock, D
Partner: UNT Libraries Government Documents Department
open access

A New Type of Steady and Stable, Laminar, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion

Description: Ultra-lean, hydrogen-air mixtures are found to support another kind of laminar flame that is steady and stable beside flat flames and flame balls. Direct numerical simulations are performed of flames that develop into steadily and stably propagating cells. These cells were the original meaning of the word"flamelet'' when they were observed in lean flammability studies conducted early in the development of combustion science. Several aspects of these two-dimensional flame cells are … more
Date: June 30, 2008
Creator: Grcar, Joseph F. & Grcar, Joseph F
Partner: UNT Libraries Government Documents Department
open access

Sensitivity study of reliable, high-throughput resolution metricsfor photoresists

Description: The resolution of chemically amplified resists is becoming an increasing concern, especially for lithography in the extreme ultraviolet (EUV) regime. Large-scale screening and performance-based down-selection is currently underway to identify resist platforms that can support shrinking feature sizes. Resist screening efforts, however, are hampered by the absence of reliable resolution metrics that can objectively quantify resist resolution in a high-throughput fashion. Here we examine two high-… more
Date: July 30, 2007
Creator: Anderson, Christopher N. & Naulleau, Patrick P.
Partner: UNT Libraries Government Documents Department
open access

Transmission electron microscopy of actinide materials

Description: Actinide metallurgy, crystallography, physics, and chemistry are of great interest due to the unique behavior of the 5f states that dominate the electronic structure. The 5f states produce a wide range of fascinating behaviors in the actinide materials. from superconductivity to exotic magnetism. Accordingly, they are of great interest, but are difficult to work with. Transmission electron microscopy (TEM) can overcome many of the problems of working with actinide materials and can be used to i… more
Date: May 30, 2006
Creator: Moore, K
Partner: UNT Libraries Government Documents Department
open access

Seeing the Unseeable

Description: The SciDAC Visualization and Analytics Center for Enabling Technologies (VACET) isa highly productive effort combining the forces of leading visualization researchersfrom five different institutions to solve some of the most challenging dataunderstanding problems in modern science. The VACET technology portfolio isdiverse, spanning all typical visual data analysis use models and effectivelybalancing forward-looking research with focused software architecture andengineering resulting in a produc… more
Date: May 30, 2008
Creator: Bethel, Edward W; Bethel, E. Wes; Johnson, Chris; Hansen, Charles; Silva, Claudio; Parker, Steven et al.
Partner: UNT Libraries Government Documents Department
open access

Frustrated spin correlations in diluted spin ice Ho2-xLaxTi2O7

Description: We have studied the evolution of the structural properties as well as the static and dynamic spin correlations of spin ice Ho2Ti2O7, where Ho was partially replaced by non-magnetic La. The crystal structure of diluted samples Ho2-xLaxTi2O7 was characterized by x-ray and neutron diffraction and by Ho L-III-edge and Ti K-edge extended x-ray absorption fine structure (EXAFS) measurements. It is found that the pyrochlore structure remains intact until about x = 0.3, but a systematic increase in loc… more
Date: April 30, 2008
Creator: Ehlers, Georg; Ehlers, G.; Mamontov, E.; Zamponi, M.; Faraone, A.; Qiu, Y. et al.
Partner: UNT Libraries Government Documents Department
open access

Patterns and Implications of Gene Gain and Loss in the Evolution of Prochlorococcus

Description: Prochlorococcus is a marine cyanobacterium that numerically dominates the mid-latitude oceans and is the smallest known oxygenic phototroph. Numerous isolatesfrom diverse areas of the world's oceans have been studied and shown to be physiologically and genetically distinct. All isolates described thus far can be assigned to either a tightly clustered high-light (HL)-adapted clade, or a more divergent low-light (LL)-adapted group. The 16S rRNA sequences of the entire Prochlorococcus group differ… more
Date: July 30, 2007
Creator: Lapidus, Alla; Kettler, Gregory C.; Martiny, Adam C.; Huang, Katherine; Zucker, Jeremy; Coleman, Maureen L. et al.
Partner: UNT Libraries Government Documents Department
open access

Solutions for Summer Electric Power Shortages: Demand Response andits Applications in Air Conditioning and Refrigerating Systems

Description: Demand response (DR) is an effective tool which resolves inconsistencies between electric power supply and demand. It further provides a reliable and credible resource that ensures stable and economical operation of the power grid. This paper introduces systematic definitions for DR and demand side management, along with operational differences between these two methods. A classification is provided for DR programs, and various DR strategies are provided for application in air conditioning and … more
Date: November 30, 2007
Creator: Han, Junqiao & Piette, Mary Ann
Partner: UNT Libraries Government Documents Department
open access

A Local Corrections Algorithm for Solving Poisson's Equation inThree Dimensions

Description: We present a second-order accurate algorithm for solving thefree-space Poisson's equation on a locally-refined nested grid hierarchyin three dimensions. Our approach is based on linear superposition oflocal convolutions of localized charge distributions, with the nonlocalcoupling represented on coarser grids. There presentation of the nonlocalcoupling on the local solutions is based on Anderson's Method of LocalCorrections and does not require iteration between different resolutions.A distribut… more
Date: October 30, 2006
Creator: McCorquodale, Peter; Colella, Phillip; Balls, Gregory T. & Baden,Scott B.
Partner: UNT Libraries Government Documents Department
open access

Plasma"anti-assistance" and"self-assistance" to high power impulse magnetron sputtering

Description: A plasma assistance system was investigated with the goal to operate high power impulse magnetron sputtering (HiPIMS) at lower pressure than usual, thereby to enhance the utilization of the ballistic atoms and ions with high kinetic energy in the film growth process. Gas plasma flow from a constricted plasma source was aimed at the magnetron target. Contrary to initial expectations, such plasma assistance turned out to be contra-productive because it led to the extinction of the magnetron disch… more
Date: January 30, 2009
Creator: Anders, Andre & Yushkov, Georgy Yu.
Partner: UNT Libraries Government Documents Department
open access

TASI Lectures on the cosmological constant

Description: The energy density of the vacuum, Lambda, is at least 60 orders of magnitude smaller than several known contributions to it. Approaches to this problem are tightly constrained by data ranging from elementary observations to precision experiments. Absent overwhelming evidence to the contrary, dark energy can only be interpreted as vacuum energy, so the venerable assumption that Lambda=0 conflicts with observation. The possibility remains that Lambda is fundamentally variable, though constant ove… more
Date: August 30, 2007
Creator: Bousso, Raphael & Bousso, Raphael
Partner: UNT Libraries Government Documents Department
open access

A cell nanoinjector based on carbon nanotubes

Description: Technologies for introducing molecules into living cells are vital for probing the physical properties and biochemical interactions that govern the cell's behavior. Here we report the development of a nanoscale cell injection system-termed the nanoinjector-that uses carbon nanotubes to deliver cargo into cells. A single multi-walled carbon nanotube attached to an atomic force microscope tip was functionalized with cargo via a disulfide-based linker. Penetration of cell membranes with this 'nano… more
Date: January 30, 2007
Creator: Chen, Xing; Kis, Andras; Zettl, Alex & Bertozzi, Carolyn R.
Partner: UNT Libraries Government Documents Department
open access

CP Violation in Hadronic Penguins at BABAR

Description: The authors present preliminary measurements of time-dependent CP-violation parameters in the decay B{sup 0} {yields} {omega}K{sub S}{sup 0}, B{sup 0} {yields} {eta}{prime}K{sup 0}, B{sup 0} {yields} {pi}{sup 0}K{sub S}{sup 0}, B{sup 0} {yields} {phi}K{sub S}{sup 0}{pi}{sup 0}, and B{sup 0} {yields} K{sup +}K{sup -}K{sub S}{sup 0}, which includes the resonant final states {phi}K{sub S}{sup 0} and f{sub 0}(980)K{sub S}{sup 0}. The data sample corresponds to the full BABAR dataset of 467 x 10{sup… more
Date: October 30, 2008
Creator: Hirschauer, J. & Collaboration, for the BABAR
Partner: UNT Libraries Government Documents Department
open access

The Soret Effect in Naturally Propagating, Premixed, Lean, Hydrogen-Air Flames

Description: Comparatively little attention has been given to multicomponent diffusion effects in lean hydrogen-air flames, in spite of the importance of these flames in safety and their potential importance to future energy technologies. Prior direct numerical simulations either have considered only the mixture-averaged transport model, or have been limited to stabilized flames that do not exhibit the thermo-diffusive instability. The so-called full, multicomponent transport model with cross-diffusion is f… more
Date: June 30, 2008
Creator: Grcar, Joseph F.; Grcar, Joseph F.; Bell, John B. & Day, Marcus S.
Partner: UNT Libraries Government Documents Department
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