Book Review Geostatistical Analysis of Compositional Data (open access)

Book Review Geostatistical Analysis of Compositional Data

Compositional data are represented as vector variables with individual vector components ranging between zero and a positive maximum value representing a constant sum constraint, usually unity (or 100 percent). The earth sciences are flooded with spatial distributions of compositional data, such as concentrations of major ion constituents in natural waters (e.g. mole, mass, or volume fractions), mineral percentages, ore grades, or proportions of mutually exclusive categories (e.g. a water-oil-rock system). While geostatistical techniques have become popular in earth science applications since the 1970s, very little attention has been paid to the unique mathematical properties of geostatistical formulations involving compositional variables. The book 'Geostatistical Analysis of Compositional Data' by Vera Pawlowsky-Glahn and Ricardo Olea (Oxford University Press, 2004), unlike any previous book on geostatistics, directly confronts the mathematical difficulties inherent to applying geostatistics to compositional variables. The book righteously justifies itself with prodigious referencing to previous work addressing nonsensical ranges of estimated values and error, spurious correlation, and singular cross-covariance matrices.
Date: March 26, 2007
Creator: Carle, S F
Object Type: Article
System: The UNT Digital Library
Surface species formed by the adsorption and dissociation of water molecules on Ru(0001) surface containing a small coverage of carbon atoms studied by scanning tunneling microscopy (open access)

Surface species formed by the adsorption and dissociation of water molecules on Ru(0001) surface containing a small coverage of carbon atoms studied by scanning tunneling microscopy

The adsorption and dissociation of water on a Ru(0001) surface containing a small amount ({le} 3 %) of carbon impurities was studied by scanning tunneling microscopy (STM). Various surface species are formed depending on the temperature. These include molecular H{sub 2}O, H{sub 2}O-C complexes, H, O, OH and CH. Clusters of either pure H{sub 2}O or mixed H{sub 2}O-OH species are also formed. Each of these species produces a characteristic contrast in the STM images and can be identified by experiment and by ab initio total energy calculations coupled with STM image simulations. Manipulation of individual species via excitation of vibrational modes with the tunneling electrons has been used as supporting evidence.
Date: April 26, 2008
Creator: UCB, Dept of Materials Science and Engineering
Object Type: Article
System: The UNT Digital Library
TESTING OF A ROTARY MICROFILTER TO SUPPORT HANFORD APPLICATIONS (open access)

TESTING OF A ROTARY MICROFILTER TO SUPPORT HANFORD APPLICATIONS

Savannah River National Laboratory (SRNL) researchers are investigating and developing a rotary microfilter for solid-liquid separation applications at the Savannah River Site (SRS). Because of the success of that work, the Hanford Site is evaluating the use of the rotary microfilter for its Supplemental Pretreatment process. The authors performed rotary filter testing with a full-scale, 25-disk unit with 0.5 {micro} filter media manufactured by Pall Corporation using a Hanford AN-105 simulant at solids loadings of 0.06, 0.29, and 1.29 wt%. The conclusions from this testing are: (1) The filter flux at 0.06 wt% solids reached a near constant value at an average of 0.26 gpm/ft{sup 2} (6.25 gpm total). (2) The filter flux at 0.29 wt% solids reached a near constant value at an average of 0.17 gpm/ft{sup 2} (4 gpm total). (3) The filter flux at 1.29 wt% solids reached a near constant value at an average of 0.10 gpm/ft{sup 2} (2.4 gpm total). (4) Because of differences in solids loadings, a direct comparison between crossflow filter flux and rotary filter flux is not possible. The data show the rotary filter produces a higher flux than the crossflow filter, but the improvement is not as large as seen in …
Date: June 26, 2008
Creator: Poirier, M; David Herman, D; David Stefanko, D & Samuel Fink, S
Object Type: Report
System: The UNT Digital Library
Melting of bcc Transition Metals and Icosahedral Clustering (open access)

Melting of bcc Transition Metals and Icosahedral Clustering

In contrast to polyvalent metals, transition metals have low melting slopes(dT/dP) that are due to partially filled d-bands that allow for a lowering of liquid phase energy through s-d electron transfer and the formation of local structures. In the case of bcc transition metals we show the apparent discrepancy of DAC melting measurements with shock melting of Mo can be understood by reexamining the shock data for V and Ta and introducing the presence of an icosahedral short range order (ISRO) melt phase.
Date: May 26, 2006
Creator: Ross, M; Boehler, R & Japel, S
Object Type: Article
System: The UNT Digital Library
Characterization of an AO-OCT system (open access)

Characterization of an AO-OCT system

Adaptive optics (AO) and optical coherence tomography (OCT) are powerful imaging modalities that, when combined, can provide high-volumetric-resolution, images of the retina. The AO-OCT system at UC Davis has been under development for 2 years and has demonstrated the utility of this technology for microscopic, volumetric, in vivo retinal imaging [1]. The current system uses an AOptix bimorph deformable mirror (DM) for low-order, high-stroke correction [2] and a 140-actuator Boston Micromachines DM for high-order correction [3]. We are beginning to investigate the potential for increasing the image contrast in this system using higher-order wavefront correction. The first step in this analysis is to quantify the residual wavefront error (WFE) in the current system. Developing an error budget is a common tool for improved performance and system design in astronomical AO systems [4, 5]. The process for vision science systems is also discussed in several texts e.g. [6], but results from this type of analysis have rarely been included in journal articles on AO for vision science. Careful characterization of the AO system will lead to improved performance and inform the design of a future high-contrast system. In general, an AO system error budget must include an analysis of three categories …
Date: July 26, 2007
Creator: Evans, J. W.; Zawadzki, R. J.; Jones, S.; Olivier, S. & Werner, J. S.
Object Type: Article
System: The UNT Digital Library
Nanostructured Assemblies of Thermoelectric Composite Materials (open access)

Nanostructured Assemblies of Thermoelectric Composite Materials

At the end of the funding period (March 2003) for our program in ferroelectric oxide nanomaterials, we had 3 publications in print, one more had been submitted and two more were in preparation in peer-reviewed journals and invited symposia lectures had been given since starting the project in the Fall of 1999. We hired two postdoctoral fellows, Dr. Ki-Seog Chang and Dr. Wenzhong Wang. We have also trained two graduate students, Ms. Keri Williams and Ms. Bernadette Hernandez, and one undergraduate student (Mr. Michael Scancella).
Date: February 26, 2008
Creator: Dorhout, Peter K. & Fisher, Ellen R.
Object Type: Report
System: The UNT Digital Library
3H(d,n)4He S-factor from Ab Initio Overlap Functions (open access)

3H(d,n)4He S-factor from Ab Initio Overlap Functions

None
Date: September 26, 2007
Creator: Navratil, P; Thompson, I & Ormand, E
Object Type: Report
System: The UNT Digital Library
ELECTRICAL SAFETY IMPROVEMENT PROJECT A COMPLEX WIDE TEAMING INITIATIVE (open access)

ELECTRICAL SAFETY IMPROVEMENT PROJECT A COMPLEX WIDE TEAMING INITIATIVE

This paper describes the results of a year-long project, sponsored by the Energy Facility Contractors Group (EFCOG) and designed to improve overall electrical safety performance throughout Department of Energy (DOE)-owned sites and laboratories. As evidenced by focused metrics, the Project was successful primarily due to the joint commitment of contractor and DOE electrical safety experts, as well as significant support from DOE and contractor senior management. The effort was managed by an assigned project manager, using classical project-management principles that included execution of key deliverables and regular status reports to the Project sponsor. At the conclusion of the Project, the DOE not only realized measurable improvement in the safety of their workers, but also had access to valuable resources that will enable them to do the following: evaluate and improve electrical safety programs; analyze and trend electrical safety events; increase electrical safety awareness for both electrical and non-electrical workers; and participate in ongoing processes dedicated to continued improvement.
Date: November 26, 2007
Creator: BJ, GRAY
Object Type: Article
System: The UNT Digital Library
Progress with Electron Beam System for the Tevatron Electron Lenses (open access)

Progress with Electron Beam System for the Tevatron Electron Lenses

None
Date: June 26, 2008
Creator: Kamerdzhiev, Vsevolod; Kuznetsov, G. F.; Saewert, G. W. & Shiltsev, V. D.
Object Type: Article
System: The UNT Digital Library
Towards an Accurate Performance Modeling of Parallel SparseFactorization (open access)

Towards an Accurate Performance Modeling of Parallel SparseFactorization

We present a performance model to analyze a parallel sparseLU factorization algorithm on modern cached-based, high-end parallelarchitectures. Our model characterizes the algorithmic behavior bytakingaccount the underlying processor speed, memory system performance, aswell as the interconnect speed. The model is validated using theSuperLU_DIST linear system solver, the sparse matrices from realapplications, and an IBM POWER3 parallel machine. Our modelingmethodology can be easily adapted to study performance of other types ofsparse factorizations, such as Cholesky or QR.
Date: May 26, 2006
Creator: Grigori, Laura & Li, Xiaoye S.
Object Type: Article
System: The UNT Digital Library
Experimental characterization of initial conditions and spatio-temporal evolution of a small Atwood number Rayleigh-Taylor mixing layer (open access)

Experimental characterization of initial conditions and spatio-temporal evolution of a small Atwood number Rayleigh-Taylor mixing layer

The initial multi-mode interfacial velocity and density perturbations present at the onset of a small Atwood number, incompressible, miscible, Rayleigh-Taylor instability-driven mixing layer have been quantified using a combination of experimental techniques. The streamwise interfacial and spanwise interfacial perturbations were measured using high-resolution thermocouples and planar laser-induced fluorescence (PLIF), respectively. The initial multi-mode streamwise velocity perturbations at the two-fluid density interface were measured using particle-image velocimetry (PIV). It was found that the measured initial conditions describe an initially anisotropic state, in which the perturbations in the streamwise and spanwise directions are independent of one another. The evolution of various fluctuating velocity and density statistics, together with velocity and density variance spectra, were measured using PIV and high-resolution thermocouple data. The evolution of the velocity and density statistics is used to investigate the early-time evolution and the onset of strongly-nonlinear, transitional dynamics within the mixing layer. The early-time evolution of the density and vertical velocity variance spectra indicate that velocity fluctuations are the dominant mechanism driving the instability development. The implications of the present experimental measurements on the initialization of Reynolds-averaged turbulent transport and mixing models and of direct and large-eddy simulations of Rayleigh-Taylor instability-induced turbulence are discussed.
Date: September 26, 2005
Creator: Mueschke, N J; Andrews, M J & Schilling, O
Object Type: Article
System: The UNT Digital Library
Cobra-IE Evaluation by Simulation of the NUPEC BWR Full-Size Fine-Mesh Bundle Test (BFBT) (open access)

Cobra-IE Evaluation by Simulation of the NUPEC BWR Full-Size Fine-Mesh Bundle Test (BFBT)

The COBRA-IE computer code is a thermal-hydraulic subchannel analysis program capable of simulating phenomena present in both PWRs and BWRs. As part of ongoing COBRA-IE assessment efforts, the code has been evaluated against experimental data from the NUPEC BWR Full-Size Fine-Mesh Bundle Tests (BFBT). The BFBT experiments utilized an 8 x 8 rod bundle to simulate BWR operating conditions and power profiles, providing an excellent database for investigation of the capabilities of the code. Benchmarks performed included steady-state and transient void distribution, single-phase and two-phase pressure drop, and steady-state and transient critical power measurements. COBRA-IE effectively captured the trends seen in the experimental data with acceptable prediction error. Future sensitivity studies are planned to investigate the effects of enabling and/or modifying optional code models dealing with void drift, turbulent mixing, rewetting, and CHF.
Date: April 26, 2006
Creator: Burns, C. J. and Aumiler, D. L.
Object Type: Article
System: The UNT Digital Library
Line-imaging velocimeter for shock diagnostics at the OMEGA laser facility (open access)

Line-imaging velocimeter for shock diagnostics at the OMEGA laser facility

None
Date: January 26, 2004
Creator: Celliers, P M; Bradley, D K; Collins, G W; Hicks, D G; Boehly, T R & Armstrong, W J
Object Type: Article
System: The UNT Digital Library
Simulation of Wakefield Effect in ILC IR Chamber (open access)

Simulation of Wakefield Effect in ILC IR Chamber

To achieve super high luminosity, high current beams with very short bunch length are needed, which carry high intensity EM fields. For ILC, two bunch trains with bunch length of 300 {micro}m and bunch charge of 3.2nC are needed to collide at the IR to achieve the ILC luminosity goals. When the 300 {micro}m bunches pass through the IR chamber, wakefields will be excited, which will cause HOM power flowing through the IR chamber beam pipe to the final doublets due to the high frequency characteristic of the induced wakefields. Since superconducting technology is adopted for the final doublets of ILC BDS, whose operation stability might be affected by the HOM power produced at the IR chamber, quench might happen. In this paper, we did some analytical estimation and numerical simulation on the wakefield effects in ILC IR chamber.
Date: June 26, 2008
Creator: Pei, S; Seryi, A. & Raubenheimer, T.O.
Object Type: Article
System: The UNT Digital Library
DENSITY-FUNCTIONAL CALCULATIONS OF ALPHA-Pu-Ga (Al) ALLOYS (open access)

DENSITY-FUNCTIONAL CALCULATIONS OF ALPHA-Pu-Ga (Al) ALLOYS

None
Date: June 26, 2006
Creator: Landa, A; Soderlind, P & Vitos, L
Object Type: Article
System: The UNT Digital Library
Multiplexed Molecular Assays for Rapid Rule-Out of Foot-and-Mouth Disease (open access)

Multiplexed Molecular Assays for Rapid Rule-Out of Foot-and-Mouth Disease

A nucleic acid-based multiplexed assay was developed that combines detection of foot-and-mouth disease virus (FMDV) with rule-out assays for two other foreign animal diseases and four domestic animal diseases that cause vesicular or ulcerative lesions indistinguishable from FMDV infection in cattle, sheep and swine. The FMDV 'look-alike' diagnostic assay panel contains five PCR and twelve reverse transcriptase PCR (RT-PCR) signatures for a total of seventeen simultaneous PCR amplifications for seven diseases plus incorporating four internal assay controls. It was developed and optimized to amplify both DNA and RNA viruses simultaneously in a single tube and employs Luminex{trademark} liquid array technology. Assay development including selection of appropriate controls, a comparison of signature performance in single and multiplex testing against target nucleic acids, as well of limits of detection for each of the individual signatures is presented. While this assay is a prototype and by no means a comprehensive test for FMDV 'look-alike' viruses, an assay of this type is envisioned to have benefit to a laboratory network in routine surveillance and possibly for post-outbreak proof of freedom from foot-and-mouth disease.
Date: June 26, 2007
Creator: Lenhoff, R; Naraghi-Arani, P; Thissen, J; Olivas, J; Carillo, C; Chinn, C et al.
Object Type: Article
System: The UNT Digital Library
High-Efficiency Solar Cells for Large-Scale Electricity Generation (open access)

High-Efficiency Solar Cells for Large-Scale Electricity Generation

One strategy for helping the solar industry to grow faster is to use very high efficiency cells under concentrating optics. By using lenses or mirrors to concentrate the light, very small solar cells can be used, reducing the amount of semiconductor material and allowing use of higher efficiency cells, which are now >40% efficient.
Date: September 26, 2008
Creator: Kurtz, S.; Olson, J.; Geisz, J.; Friedman, D.; McMahon, W.; Ptak, A. et al.
Object Type: Article
System: The UNT Digital Library
EUV mask reflectivity measurements with micron-scale spatial resolution (open access)

EUV mask reflectivity measurements with micron-scale spatial resolution

The effort to produce defect-free mask blanks for EUV lithography relies on increasing the detection sensitivity of advanced mask inspection tools, operating at several wavelengths. We describe the unique measurement capabilities of a prototype actinic (EUV wavelength) microscope that is capable of detecting small defects and reflectivity changes that occur on the scale of microns to nanometers. Types of defects: (a) Buried Substrate Defects: particles & pits (causes amplitude and/or phase variations); (b) Surface Contamination (reduces reflectivity and (possibly) contrast); (c) Damage from Inspection and Use (reduces the reflectivity of the multilayer coating). This paper presents an overview of several topics where scanning actinic inspection makes a unique contribution to EUVL research. We describe the role of actinic scanning inspection in four cases: defect repair studies; observations of laser damage; after scanning electron microscopy; and native and programmed defects.
Date: May 26, 2008
Creator: Goldberg, Kenneth A.; Rekawa, S. B.; Kemp, C. D.; Barty, A.; Anderson, E. H.; Kearney, Patrick et al.
Object Type: Article
System: The UNT Digital Library
AMMONIA CONCENTRATION IN SALTSTONE HEADSPACE SUMMARY REPORT (open access)

AMMONIA CONCENTRATION IN SALTSTONE HEADSPACE SUMMARY REPORT

The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar into Tank 50. Saltstone samples were prepared with an 'MCU' type salt solution spiked with ammonia. The ammonia released from the saltstone was captured and analyzed. The ammonia concentration found in the headspace of samples maintained at 95 C and 1 atm was, to 95% confidence, less than or equal to 3.9 mg/L. Tank 50 is fed by several influent streams. The salt solution from Tank 50 is pumped to the salt feed tank (SFT) in the Saltstone Production Facility (SPF). The premix materials cement, slag and fly ash are blended together prior to transfer to the grout mixer. The premix is fed to the grout mixer in the SPF and the salt solution is incorporated into the premix in the grout mixer, yielding saltstone slurry. The saltstone slurry drops into a hopper and then is pumped to the vault. The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar{reg_sign} L into Tank 50. Waste Solidification-Engineering requested that the Savannah …
Date: September 26, 2008
Creator: Zamecnik, J & Alex Cozzi, A
Object Type: Report
System: The UNT Digital Library
Hanford Site Environmental Surveillance Data Report for Calendar Year 2006 (open access)

Hanford Site Environmental Surveillance Data Report for Calendar Year 2006

This document includes tables of analytical data for Hanford Site environmental surveillance samples collected in 2006.
Date: September 26, 2007
Creator: Bisping, Lynn E.
Object Type: Report
System: The UNT Digital Library
PDV Probe Alignment Technique (open access)

PDV Probe Alignment Technique

This alignment technique was developed while performing heterodyne velocimetry measurements at LLNL. There are a few minor items needed, such as a white card with aperture in center, visible alignment laser, IR back reflection meter, and a microscope to view the bridge surface. The work was performed on KCP flyers that were 6 and 8 mils wide. The probes used were Oz Optics manufactured with focal distances of 42mm and 26mm. Both probes provide a spot size of approximately 80?m at 1550nm. The 42mm probes were specified to provide an internal back reflection of -35 to -40dB, and the probe back reflections were measured to be -37dB and -33dB. The 26mm probes were specified as -30dB and both measured -30.5dB. The probe is initially aligned normal to the flyer/bridge surface. This provides a very high return signal, up to -2dB, due to the bridge reflectivity. A white card with a hole in the center as an aperture can be used to check the reflected beam position relative to the probe and launch beam, and the alignment laser spot centered on the bridge, see Figure 1 and Figure 2. The IR back reflection meter is used to measure the dB return …
Date: October 26, 2007
Creator: Whitworth, T L; May, C M & Strand, O T
Object Type: Report
System: The UNT Digital Library
Colliding with a crunching bubble (open access)

Colliding with a crunching bubble

In the context of eternal inflation we discuss the fate of Lambda = 0 bubbles when they collide with Lambda< 0 crunching bubbles. When the Lambda = 0 bubble is supersymmetric, it is not completely destroyed by collisions. If the domain wall separating the bubbles has higher tension than the BPS bound, it is expelled from the Lambda = 0 bubble and does not alter its long time behavior. If the domain wall saturates the BPS bound, then it stays inside the Lambda = 0 bubble and removes a finite fraction of future infinity. In this case, the crunch singularity is hidden behind the horizon of a stable hyperbolic black hole.
Date: March 26, 2007
Creator: Freivogel, Ben; Freivogel, Ben; Horowitz, Gary T. & Shenker, Stephen
Object Type: Article
System: The UNT Digital Library
B365 High Efficiency Particulate Air Filter Emergency Replacement An Example of Team Work (open access)

B365 High Efficiency Particulate Air Filter Emergency Replacement An Example of Team Work

None
Date: September 26, 2006
Creator: Coble, T; Little, C & Johnson, R
Object Type: Article
System: The UNT Digital Library
Beam Collimation Studies for the ILC Positron Source (open access)

Beam Collimation Studies for the ILC Positron Source

Results of the collimation studies for the ILC positron source beam line are presented. The calculations of primary positron beam loss are done using the ELEGANT code. The secondary positron and electron beam loss, the synchrotron radiation along the beam line and the bremsstrahlung radiation in the collimators are simulated using the STRUCT code. The first part of the collimation system, located right after the positron source target (0.125 GeV), is used for protection of the RF Linac sections from heating and radiation. The second part of the system is used for final collimation before the beam injection into the Damping Ring at 5 GeV. The calculated power loss in the collimation region is within 100 W/m, with the loss in the collimators of 0.2-5 kW. The beam transfer efficiency from the target to the Damping Ring is 13.5%.
Date: June 26, 2008
Creator: Drozhdin, A.; Nosochkov, Y. & Zhou, F.
Object Type: Article
System: The UNT Digital Library