3,512 Matching Results

Results open in a new window/tab.

Solubility prediction of salicylic acid in water-ethanol-propylene glycol mixtures using the Jouyban-Acree model (open access)

Solubility prediction of salicylic acid in water-ethanol-propylene glycol mixtures using the Jouyban-Acree model

Article on the solubility prediction of salicylic acid in water-ethanol-propylene glycol mixtures using the Jouyban-Acree model.
Date: 2006
Creator: Jouyban, Abolghasem; Chew, Nora Yat Knork; Chan, H.; Khoubnasabjafari, M. & Acree, William E. (William Eugene)
System: The UNT Digital Library
First-principles theory of metal-alkaline earth oxide interfaces (open access)

First-principles theory of metal-alkaline earth oxide interfaces

Article on the first-principles theory of metal-alkaline earth oxide interfaces.
Date: June 21, 2006
Creator: Nuñez, Matías & Buongiorno Nardelli, Marco
System: The UNT Digital Library
Widows and Riccoboni's Lettres d'Adélaïde de Dammartin (open access)

Widows and Riccoboni's Lettres d'Adélaïde de Dammartin

Article on widows and Marie Jeanne Riccoboni's 'Lettres d'Adélaïde de Dammartin.' This is a selected essay from the Women in French International Conference in 2006.
Date: 2006
Creator: Kaplan, Marijn S.
System: The UNT Digital Library
Councilor's Report: 2006 Midwinter Meeting - San Antonio (open access)

Councilor's Report: 2006 Midwinter Meeting - San Antonio

This article discusses the American Library Association (ALA) midwinter meeting in 2006, which was held in San Antonio. The discussions include an increase in dues and several resolutions.
Date: 2006
Creator: Hartman, Cathy Nelson
System: The UNT Digital Library
Councilor's Report: 2006 Annual Conference - New Orleans (open access)

Councilor's Report: 2006 Annual Conference - New Orleans

This article discusses the American Library Association (ALA) Annual Conference in 2006, which took place in New Orleans, Louisiana. Information about the topics discussed and issues that were brought up are included.
Date: 2006
Creator: Hartman, Cathy Nelson
System: The UNT Digital Library
The Depository Library Community and Collaborative Participation in E-Government: AskUS (FDLP Librarians) and We Will Answer! (open access)

The Depository Library Community and Collaborative Participation in E-Government: AskUS (FDLP Librarians) and We Will Answer!

This book chapter examines the federal Executive Branch and Congressional vision of e-government and the role of the Government Printing Office's (GPO) Federal Depository Library Program (FDLP) to demonstrate how the FDLP can effectively participate in existing e-government initiatives. The continuation of the Federal Depository Library Program's historic information dissemination, access, and preservation roles are now dependent upon multi-agency e-government collaboration. The collections and research expertise of Federal Depository libraries are the critical features missing in current e-government service models. The authors propose that the public service and resource discovery features now available at FDLP libraries be coordinated nationally via an AskUS-FDLP Library Portal.
Date: 2006
Creator: Kelly, Melody Specht & Hartman, Cathy Nelson
System: The UNT Digital Library
Renewal, Modulation, and Superstatistics in Times Series (open access)

Renewal, Modulation, and Superstatistics in Times Series

Article discussing two different approaches, referred to as renewal and modulation, to generate time series with a nonexponential distribution of waiting times.
Date: April 27, 2006
Creator: Allegrini, Paolo; Barbi, Francesco; Grigolini, Paolo & Paradisi, Paolo
System: The UNT Digital Library
Oxidation of alloys targeted for advanced steam turbines (open access)

Oxidation of alloys targeted for advanced steam turbines

Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of alloys for use in USC systems, with emphasis placed on applications in high- and intermediate-pressure turbines.
Date: March 12, 2006
Creator: Holcomb, G. R.; Covino, B. S., Jr.; Bullard, S. J.; Ziomek-Moroz, M. & Alman, D. E.
System: The UNT Digital Library
THz radiation as a bunch diagnostic forlaser-wakefield-accelerated electron bunches (open access)

THz radiation as a bunch diagnostic forlaser-wakefield-accelerated electron bunches

Experimental results are reported from two measurementtechniques (semiconductor switching and electro-optic sampling) thatallow temporal characterization of electron bunches produced by alaser-driven plasma-based accelerator. As femtosecond electron bunchesexit the plasma-vacuum interface, coherent transition radiation (at THzfrequencies) is emitted. Measuring the properties of this radiationallows characterization of the electron bunches. Theoretical work on theemission mechanism is represented, including a model that calculates theTHz waveform from a given bunch profile. It is found that the spectrum ofthe THz pulse is coherent up to the 200 mu m thick crystal (ZnTe)detection limit of 4 THz, which corresponds to the production of sub-50fs (root-mean-square) electron bunch structure. The measurementsdemonstrate both the shot-to-shot stability of bunch parameters that arecritical to THz emission (such as total charge and bunch length), as wellas femtosecond synchrotron between bunch, THz pulse, and laserbeam.
Date: February 15, 2006
Creator: van Tilborg, J.; Schroeder, C. B.; Filip, C. V.; Toth, Cs.; Geddes, C. G. R.; Fubiani, G. et al.
System: The UNT Digital Library
Magnet R&D for the US LHC Accelerator Research Program (LARP) (open access)

Magnet R&D for the US LHC Accelerator Research Program (LARP)

In 2004, the US DOE established the LHC Accelerator Research Program (LARP) with the goal of developing a technology base for future upgrades of the LHC. The focus of the magnet program, which is a collaboration of three US laboratories, BNL, FNAL and LBNL, is on development of high gradient quadrupoles using Nb{sub 3}Sn superconductor. Other program components address issues regarding magnet design, radiation-hard materials, long magnet scale-up, quench protection, fabrication techniques and conductor and cable R&D. This paper presents an overall view of the program with emphasis on the current quadrupole project and outlines the long-term goals of the program.
Date: June 1, 2006
Creator: Gourlay, S. A.; Ambrosio, G.; Andreev, N.; Anerella, M.; Barzi, E.; Bossert, R. et al.
System: The UNT Digital Library
Stochastic Transport Modeling of Resonant Magnetic Perturbations in DIII-D (open access)

Stochastic Transport Modeling of Resonant Magnetic Perturbations in DIII-D

Three-dimensional two-fluid simulations of heat transport due to resonant magnetic perturbations of tokamaks have been computed by coupling the TRIP3D field line tracing code to the E3D edge transport code. The predicted electron temperature contours follow the new separatrix represented by the perturbed invariant manifold structure of the X-point in qualitative agreement with X-point TV observations. However, preliminary modeling predicts that the resulting stochastic heat transport is greater than that measured in low-collisionality ELM suppression experiments in DIII-D H-mode plasmas. While improved determination of transport coefficients is definitely required, possible explanations include plasma screening of resonant perturbations, invalid treatment of the edge as a fluid, or insufficient understanding of stochastic heat transport.
Date: June 1, 2006
Creator: Joseph, I.; Moyer, R. A.; Evans, T. E.; Schaffer, M. J.; Runov, A. M.; Schneider, R. et al.
System: The UNT Digital Library
Adapting Existing Spatial Data Sets to New Uses: An Example from Energy Modeling (open access)

Adapting Existing Spatial Data Sets to New Uses: An Example from Energy Modeling

Energy modeling and analysis often relies on data collected for other purposes such as census counts, atmospheric and air quality observations, and economic projections. These data are available at various spatial and temporal scales, which may be different from those needed by the energy modeling community. If the translation from the original format to the format required by the energy researcher is incorrect, then resulting models can produce misleading conclusions. This is of increasing importance, because of the fine resolution data required by models for new alternative energy sources such as wind and distributed generation. This paper addresses the matter by applying spatial statistical techniques which improve the usefulness of spatial data sets (maps) that do not initially meet the spatial and/or temporal requirements of energy models. In particular, we focus on (1) aggregation and disaggregation of spatial data, (2) imputing missing data and (3) merging spatial data sets.
Date: June 23, 2006
Creator: Johanesson, G; Stewart, J S; Barr, C; Sabeff, L B; George, R; Heimiller, D et al.
System: The UNT Digital Library
Accurate labeling of the light-actinide O4,5 ionization edges (open access)

Accurate labeling of the light-actinide O4,5 ionization edges

In this short article the accurate labeling of the O4,5 edges of the light actinides is addressed. The O4 and O5 edges are both contained in what is termed the ''giant resonance'' and the smaller ''pre-peak'' that is observed is a consequence of first-order perturbation by the 5d spin-orbit interaction. Thus, the small prepeak in the actinide 5d {yields} 5f transition should not be labeled the O5 peak, but rather the {Delta}S=1 peak.
Date: August 23, 2006
Creator: Moore, K & der Laan, G v
System: The UNT Digital Library
Elastic electron scattering from formic acid (open access)

Elastic electron scattering from formic acid

Following our earlier study on the dynamics of low energy electron attachment to formic acid, we report the results of elastic low-energy electron collisions with formic acid. Momentum transfer and angular differential cross sections were obtained by performing fixed-nuclei calculations employing the complex Kohn variational method. We make a brief description of the technique used to account for the polar nature of this polyatomic target and compare our results with available experimental data.
Date: July 31, 2006
Creator: Trevisan, Cynthia S.; Orel, Ann E. & Rescigno, Thomas N.
System: The UNT Digital Library
First Principles Study of Double Photoionization of H2 UsingExterior Complex Scaling (open access)

First Principles Study of Double Photoionization of H2 UsingExterior Complex Scaling

Exterior complex scaling provides a practical path forfirst-principles studies of atomic and molecular ionizationproblemssince it avoids explicit enforcement of asymptotic boundary conditionsfor 3-body Coulomb breakup. We have used the method of exterior complexscaling, implemented with both the discrete variable representation andB-splines, to obtain the first-order wave function for molecular hydrogencorresponding to a single photon having been absorbed by a correlatedinitial state. These wave functions are used to construct convergedtriple differential cross sections for double photoionization of alignedH2 molecules.
Date: July 21, 2006
Creator: Rescigno, Thomas N.; Vanroose, Wim; Horner, Daniel A.; Martin,Fernando & McCurdy, C. William
System: The UNT Digital Library
Extending the cereus group genomics to putative food-borne pathogens of different toxicity (open access)

Extending the cereus group genomics to putative food-borne pathogens of different toxicity

The cereus group represents sporulating soil bacteriacontaining pathogenic strains which may cause diarrheic or emetic foodpoisoning outbreaks. Multiple locus sequence typing revealed a presencein natural samples of these bacteria of about thirty clonal complexes.Application of genomic methods to this group was however biased due tothe major interest for representatives closely related to B. anthracis.Albeit the most important food-borne pathogens were not yet defined,existing dataindicate that they are scattered all over the phylogenetictree. The preliminary analysis of the sequences of three genomesdiscussed in this paper narrows down the gaps in our knowledge of thecereus group. The strain NVH391-98 is a rare but particularly severefood-borne pathogen. Sequencing revealed that the strain must be arepresentative of a novel bacterial species, for which the name Bacilluscytotoxis is proposed. This strain has a reduced genome size compared toother cereus group strains. Genome analysis revealed absence of sigma Bfactor and the presence of genes encoding diarrheic Nhe toxin, notdetected earlier. The strain B. cereus F837/76 represents a clonalcomplex close to that of B. anthracis. Including F837/76, three such B.cereus strains had been sequenced. Alignment of genomes suggests that B.anthracis is their common ancestor. Since such strains often emerge fromclinical cases, they merit a special attention. The …
Date: August 24, 2006
Creator: Lapidus, Alla; Goltsman, Eugene; Auger, Sandrine; Galleron, Nathalie; Segurens, Beatrice; Dossat, Carole et al.
System: The UNT Digital Library
High-resolution simulations and modeling of reshocked single-mode Richtmyer-Meshkov instability. I. Comparison to experimental data and to amplitude growth model predictions (open access)

High-resolution simulations and modeling of reshocked single-mode Richtmyer-Meshkov instability. I. Comparison to experimental data and to amplitude growth model predictions

The reshocked single-mode Richtmyer-Meshkov instability is simulated in two spatial dimensions using the fifth- and ninth-order weighted essentially non-oscillatory shock-capturing method with uniform spatial resolution of 256 points per initial perturbation wavelength. The initial conditions and computational domain are modeled after the single-mode, Mach 1.21 air(acetone)/SF{sub 6} shock tube experiment of Collins and Jacobs [J. Fluid Mech. 464, 113 (2002)]. The simulation densities are shown to be in very good agreement with the corrected experimental planar laser-induced fluorescence images at selected times before reshock of the evolving interface. Analytical, semianalytical and phenomenological linear and nonlinear, impulsive, perturbation and potential flow models for single-mode Richtmyer-Meshkov unstable perturbation growth are summarized. The simulation amplitudes are shown to be in very good agreement with the experimental data and with the predictions of linear amplitude growth models for small times and with those of nonlinear amplitude growth models at later times up to the time at which the driver-based expansion in the experiment (but not present in the simulations or models) expands the layer before reshock. The qualitative and quantitative differences between the fifth- and ninth-order simulation results are discussed. Using a local and global quantitative metric, the prediction of the Zhang and Sohn …
Date: May 15, 2006
Creator: Latini, M; Schilling, O & Don, W
System: The UNT Digital Library
A fast contour descriptor algorithm for supernova imageclassification (open access)

A fast contour descriptor algorithm for supernova imageclassification

We describe a fast contour descriptor algorithm and its application to a distributed supernova detection system (the Nearby Supernova Factory) that processes 600,000 candidate objects in 80 GB of image data per night. Our shape-detection algorithm reduced the number of false positives generated by the supernova search pipeline by 41% while producing no measurable impact on running time. Fourier descriptors are an established method of numerically describing the shapes of object contours, but transform-based techniques are ordinarily avoided in this type of application due to their computational cost. We devised a fast contour descriptor implementation for supernova candidates that meets the tight processing budget of the application. Using the lowest-order descriptors (F{sub 1} and F{sub -1}) and the total variance in the contour, we obtain one feature representing the eccentricity of the object and another denoting its irregularity. Because the number of Fourier terms to be calculated is fixed and small, the algorithm runs in linear time, rather than the O(n log n) time of an FFT. Constraints on object size allow further optimizations so that the total cost of producing the required contour descriptors is about 4n addition/subtraction operations, where n is the length of the contour.
Date: July 16, 2006
Creator: Aragon, Cecilia R. & Aragon, David Bradburn
System: The UNT Digital Library
An Analysis of the DER Adoption Climate in Japan UsingOptimization Results for Prototype Buildings with U.S. Comparisons (open access)

An Analysis of the DER Adoption Climate in Japan UsingOptimization Results for Prototype Buildings with U.S. Comparisons

This research demonstrates economically optimal distributedenergy resource (DER) system choice using the DER choice and operationsoptimization program, the Distributed Energy Resources Customer AdoptionModel (DER-CAM). DER-CAM finds the optimal combination of installedequipment given prevailing utility tariffs and fuel prices, siteelectrical and thermal loads (including absorption cooling), and a menuof available equipment. It provides a global optimization, albeitidealized, that shows how site useful energy loads can be served atminimum cost. Five prototype Japanese commercial buildings are examinedand DER-CAM is applied to select the economically optimal DER system foreach. Based on the optimization results, energy and emission reductionsare evaluated. Significant decreases in fuel consumption, carbonemissions, and energy costs were seen in the DER-CAM results. Savingswere most noticeable in the prototype sports facility, followed by thehospital, hotel, and office building. Results show that DER with combinedheat and power equipment is a promising efficiency and carbon mitigationstrategy, but that precise system design is necessary. Furthermore, aJapan-U.S. comparison study of policy, technology, and utility tariffsrelevant to DER installation is presented.
Date: June 16, 2006
Creator: Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun & Nishida,Masaru
System: The UNT Digital Library
System-level modeling for geological storage of CO2 (open access)

System-level modeling for geological storage of CO2

One way to reduce the effects of anthropogenic greenhousegases on climate is to inject carbon dioxide (CO2) from industrialsources into deep geological formations such as brine formations ordepleted oil or gas reservoirs. Research has and is being conducted toimprove understanding of factors affecting particular aspects ofgeological CO2 storage, such as performance, capacity, and health, safetyand environmental (HSE) issues, as well as to lower the cost of CO2capture and related processes. However, there has been less emphasis todate on system-level analyses of geological CO2 storage that considergeological, economic, and environmental issues by linking detailedrepresentations of engineering components and associated economic models.The objective of this study is to develop a system-level model forgeological CO2 storage, including CO2 capture and separation,compression, pipeline transportation to the storage site, and CO2injection. Within our system model we are incorporating detailedreservoir simulations of CO2 injection and potential leakage withassociated HSE effects. The platform of the system-level modelingisGoldSim [GoldSim, 2006]. The application of the system model is focusedon evaluating the feasibility of carbon sequestration with enhanced gasrecovery (CSEGR) in the Rio Vista region of California. The reservoirsimulations are performed using a special module of the TOUGH2 simulator,EOS7C, for multicomponent gas mixtures of methane and CO2 or methane andnitrogen. …
Date: April 24, 2006
Creator: Zhang, Yingqi; Oldenburg, Curtis M.; Finsterle, Stefan & Bodvarsson, Gudmundur S.
System: The UNT Digital Library
"When the Safety System Fails the Worker: Did We Do Our Job?...a Case Study" (open access)

"When the Safety System Fails the Worker: Did We Do Our Job?...a Case Study"

None
Date: May 12, 2006
Creator: McConnell, S
System: The UNT Digital Library
Effects of Fe spin transition on the elasticity of (Mg,Fe)O magnesiow�ustites and implications for the seismological properties of the Earth's lower mantle (open access)

Effects of Fe spin transition on the elasticity of (Mg,Fe)O magnesiow�ustites and implications for the seismological properties of the Earth's lower mantle

High-pressure x-ray diffraction of (Mg{sub 0.8}Fe{sub 0.2})O at room temperature reveals a discontinuity in the bulk modulus at 40 ({+-}5) GPa, similar pressure at which an electronic spin-pairing transition of Fe{sup 2+} is also observed. In the x-ray diffraction experiments the transition is completed only at 80 GPa, possibly reflecting lack of equilibration. Combining recent measurements, we document anomalies in the compression curve of Mg-rich magnesiowuestites that are manifestations of the spin transition. The best fit to a third order Birch-Murnaghan equation for the low-spin phase of magnesiowuestite with 17-20 mol% FeO yields bulk modulus K{sub T0} = 190 ({+-}150) GPa, pressure derivative ({partial_derivative}K{sub T}/{partial_derivative}){sub T0} = 4.6 ({+-}2.7) and unit-cell volume V{sub 0} = 71 ({+-}5) {angstrom}{sup 3}, consistent with past estimates of the ionic radius of octahedrally-coordinated low-spin Fe{sup 2+} in oxides. A sharp spin transition at lower-mantle depths between 1100 and 1900 km (40-80 GPa) would cause a unit-cell volume decrease ({Delta}{nu}{sub {phi}}) of 3.7 ({+-}0.8) to 2.0 ({+-}0.2) percent and bulk sound velocity increase ({Delta}{nu}{sub {phi}}) of 8.1 ({+-}6-1.7) percent ({nu}{sub {phi}} = {radical}K{sub s}/{rho}). Even in the absence of a visible seismic discontinuity, we expect the Fe-spin transition to imply a correction to current compositional …
Date: August 29, 2006
Creator: Speziale, S; Lee, V E; Clark, S M; Lin, J F; Pasternak, M P & Jeanloz, R
System: The UNT Digital Library
A Top to Bottom Lithospheric Study of Africa and Arabia (open access)

A Top to Bottom Lithospheric Study of Africa and Arabia

We study the lithospheric structure of Africa, Arabia and adjacent oceanic regions with fundamental-mode surface waves over a wide period range. Including short period group velocities allows us to examine shallower features than previous studies of the whole continent. In the process, we have developed a crustal thickness map of Africa. Main features include crustal thickness increases under the West African, Congo, and Kalahari cratons. We find crustal thinning under Mesozoic and Cenozoic rifts, including the Benue Trough, Red Sea, and East, Central, and West African rift systems. Crustal shear wave velocities are generally faster in oceanic regions and cratons, and slower in more recent crust and in active and formerly active orogenic regions. Deeper structure, related to the thickness of cratons and modern rifting, is generally consistent with previous work. Under cratons we find thick lithosphere and fast upper mantle velocities, while under rifts we find thinned lithosphere and slower upper mantle velocities. There are no consistent effects in areas classified as hotspots, indicating that there seem to be numerous origins for these features. Finally, it appears that the African Superswell has had a significantly different impact in the north and the south, indicating specifics of the feature (temperature, …
Date: October 31, 2006
Creator: Pasyanos, M
System: The UNT Digital Library
Fine-scale Horizontal Structure of Arctic Mixed-Phase Clouds. (open access)

Fine-scale Horizontal Structure of Arctic Mixed-Phase Clouds.

Recent in situ observations in stratiform clouds suggest that mixed phase regimes, here defined as limited cloud volumes containing both liquid and solid water, are constrained to narrow layers (order 100 m) separating all-liquid and fully glaciated volumes (Hallett and Viddaurre, 2005). The Department of Energy Atmospheric Radiation Measurement Program's (DOE-ARM, Ackerman and Stokes, 2003) North Slope of Alaska (NSA) ARM Climate Research Facility (ACRF) recently started collecting routine measurement of radar Doppler velocity power spectra from the Millimeter Cloud Radar (MMCR). Shupe et al. (2004) showed that Doppler spectra has potential to separate the contributions to the total reflectivity of the liquid and solid water in the radar volume, and thus to investigate further Hallett and Viddaurre's findings. The Mixed-Phase Arctic Cloud Experiment (MPACE) was conducted along the NSA to investigate the properties of Arctic mixed phase clouds (Verlinde et al., 2006). We present surface based remote sensing data from MPACE to discuss the fine-scale structure of the mixed-phase clouds observed during this experiment.
Date: July 10, 2006
Creator: Rambukkange,M.; Verlinde, J.; Elorante, E.; Luke, E.; Kollias, P. & Shupe, M.
System: The UNT Digital Library