2.1 Pan-WCRP Monsoon Modelling Workshop Summary (open access)

2.1 Pan-WCRP Monsoon Modelling Workshop Summary

Ken Sperber led a discussion of the outcome of the Pan-WCRP Monsoon Modelling Workshop that was held at the University of California at Irvine from 15-17 June 2005. At the workshop presentations from key CLIVAR and GEWEX panels were presented to highlight the outstanding problems in modelling the Earth's monsoons. Additionally, presentations from invited experts were given to highlight important aspects of monsoon phenomena and processes, such as low-level jets, air-sea interaction, predictability, observational networks/studies, and model test beds etc. Since all persons attending the CLIVAR AAMP meeting were present for all, or most, of the monsoon workshop, a detailed description of the workshop presentations was not given. Rather, the discussion was focused on the recommendations of the workshop breakout groups and their relevance to CLIVAR AAMP. CLIVAR AAMP endorsed the near-term workshop recommendation of investigating the diurnal cycle using a hierarchy of models a key way forward for promoting CLIVAR/GEWEX interactions. In GCM studies CLIVAR researchers have identified the diurnal cycle as a forced ''mode'' of variability that is poorly represented in terms of amplitude and phase, especially in the case of precipitation. Typical phase errors of 6-12 hours are noted over both land and ocean in GCMs. CLIVAR …
Date: June 28, 2005
Creator: Sperber, K R
Object Type: Report
System: The UNT Digital Library
2-D or not 2-D, that is the question: A Northern California test (open access)

2-D or not 2-D, that is the question: A Northern California test

Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. The complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Using the same station and event distribution, we compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance …
Date: June 6, 2005
Creator: Mayeda, K; Malagnini, L; Phillips, W S; Walter, W R & Dreger, D
Object Type: Article
System: The UNT Digital Library
3-D Seismic Experimentation and Advanced Processing/Inversion Development for Investigations of the Shallow Subsurface (open access)

3-D Seismic Experimentation and Advanced Processing/Inversion Development for Investigations of the Shallow Subsurface

Gian Fradelizio, a Rice Ph.D. student has completed reprocessing the 3D seismic reflection data acquired at Hill AFB through post-stack depth migration for comparison to the traveltime and waveform tomography results. Zelt, Levander, Fradelizio, and 5 others spent a week at Hill AFB in September 2005, acquiring an elastic wave data set along 2 profiles. We used 60 3-component Galperin mounted 40 Hz geophones recorded by 3 GEOMETRICS Stratavision systems. The seismic source employed was a sledgehammer used to generate transverse, and radial, and vertical point source data. Data processing has begun at Rice to generate S-wave reflection and refraction images. We also acquired surface wave and ground penetrating rada data to complement the elastic wave dataset.
Date: June 1, 2005
Creator: Levander, Alan R.
Object Type: Report
System: The UNT Digital Library
2005 Atomic Physics Gordon Conference, June 26-July 1, 2005 (open access)

2005 Atomic Physics Gordon Conference, June 26-July 1, 2005

This article is a detailed description of the Gordon Research Conference on Atomic Physics.
Date: June 25, 2005
Creator: Monroe, Christopher
Object Type: Article
System: The UNT Digital Library
2005 Habitat Evaluation Procedure (HEP) Report for the Carey Creek Project (open access)

2005 Habitat Evaluation Procedure (HEP) Report for the Carey Creek Project

In August 2002, the Habitat Evaluation Procedure (HEP) was used to determine baseline habitat suitability on the Carey Creek property, an acquisition completed by the Kalispel Tribe of Indians in December 2001. Evaluation species and appropriate models include bald eagle, black-capped chickadee, Canada goose, mallard, yellow warbler, and white-tailed deer. Habitat Suitability Index (HSI) values were visually estimated and agreed upon by all HEP team members. The Carey Creek Project provides a total of 172.95 Habitat Units (HUs) for the species evaluated. Conifer forest habitat provides 4.91 HUs for bald eagle, black-capped chickadee, and white-tailed deer. Forested wetlands provide 52.68 HUs for bald eagle, black-capped chickadee, mallard, and white-tailed deer. Scrub-shrub wetlands provide 2.82 HUs for mallard, yellow warbler and white-tailed deer. Wet meadow and grassland meadow provide 98.13 HUs for mallard and Canada goose. Emergent wetlands provide 11.53 HUs for mallard, muskrat, and Canada goose. Open water provides 2.88 HUs for Canada goose, mallard, and muskrat. The objective of using HEP at the Carey Creek Project and other protected properties is to document the quality and quantity of available habitat for selected wildlife species. In this way, HEP provides information on the relative value of the same area at …
Date: June 2005
Creator: Entz, Ray
Object Type: Report
System: The UNT Digital Library
3D Numerical Experimentation on the Core Helium Flash of Low-mass Red Giants (open access)

3D Numerical Experimentation on the Core Helium Flash of Low-mass Red Giants

None
Date: June 28, 2005
Creator: Dearborn, D. S. P.; Lattanzio, J. C. & Eggleton, P. P.
Object Type: Article
System: The UNT Digital Library
An Ab Initio Approach Towards Engineering Fischer-Tropsch Surface Chemistry (open access)

An Ab Initio Approach Towards Engineering Fischer-Tropsch Surface Chemistry

As petroleum prices continue to rise and the United States seeks to reduce its dependency on foreign oil, there is a renewed interest in the research and development of more efficient and alternative energy sources, such as fuel cells. One approach is to utilize processes that can produce long-chain hydrocarbons from other sources. One such reaction is Fischer-Tropsch synthesis. Fischer-Tropsch synthesis is a process by which syngas (CO and H{sub 2}) is converted to higher molecular weight hydrocarbons. The reaction involves a complex set of bond-breaking and bond-making reactions, such as CO and H{sub 2} activation, hydrocarbon hydrogenation reactions, and hydrocarbon coupling reactions. This report details our initial construction of an ab initio based kinetic Monte Carlo code that can be used to begin to simulate Fischer-Tropsch synthesis over model Co(0001) surfaces. The code is based on a stochastic kinetic formalism that allows us to explicitly track the transformation of all reactants, intermediates and products. The intrinsic kinetics for the simulations were derived from the ab initio results that we reported in previous year summaries.
Date: June 13, 2005
Creator: Neurock, Matthew
Object Type: Report
System: The UNT Digital Library
Absolute X-Ray Yields From Laser-Irradiated, Ge-Doped Aerogel Targets (open access)

Absolute X-Ray Yields From Laser-Irradiated, Ge-Doped Aerogel Targets

Bright, multi-keV x-ray sources are essential for radiography of inertial-confinement fusion (ICF) experiments. In this context, there are two parameters of importance: the energy of the emitted photons, which determines how penetrating the x-rays are for radiographic purposes, and the brightness of the source, which determines the ability of a radiograph to resolve small features. As ICF experiments continue to get larger, such as those that will be carried out at the National Ignition Facility at Lawrence Livermore National Laboratory, or at the French Commissariat a l'Energie Atomique's (CEA) Laser MegaJoule, and compression in fuel capsules gets higher, sources for x-ray backlighting will have to have harder-photon spectra. For a given laser energy available to drive the multi-keV x-ray-backlight source, the only way for the source to get brighter is for it to convert the laser to x-rays more efficiently. We have been developing and characterizing laser-driven, underdense x-ray sources that are highly efficient in recent years [2-5]. CEA researchers have also recently had great success efficiently making multi-keV x-rays from pre-pulsed foils [6].
Date: June 15, 2005
Creator: Fournier, K. B.; Tobin, M.; Poco, J. F.; Bradley, K.; Coverdale, C. A.; Beutler, D. et al.
Object Type: Article
System: The UNT Digital Library
Acceleration of calcite kinetics by abalone nacre proteins (open access)

Acceleration of calcite kinetics by abalone nacre proteins

The fascinating shapes and hierarchical designs of biomineralized structures have long been an inspiration to materials scientists because of the potential they suggest for biomolecular control over synthesis of crystalline materials. One prevailing view is that mineral-associated macromolecules are responsible for initiating and stabilizing non-equilibrium crystal polymorphs and morphologies through interactions between anionic moieties and cations in solution or at mineral surfaces. Indeed, numerous studies have demonstrated that bio-organic additives can dramatically alter crystal shapes and growth-rates in vitro. However, previous molecular-scale studies revealing mechanisms of growth modification focused on small molecules such as amino acids or peptides and always observed growth inhibition. In contrast, studies using full proteins were non-quantitative and underlying sources of growth modification were ill-defined. Here we investigate interactions between proteins isolated from abalone shell nacre and growing surfaces of calcite. We find that these proteins significantly accelerate the molecular-scale kinetics and, though much larger than atomic steps, alter growth morphology through step-specific interactions that lower their free energies. We propose that these proteins act as surfactants to promote ion attachment at calcite surfaces.
Date: June 9, 2005
Creator: Fu, G.; Qiu, S. R.; Orme, C. A.; Morse, D. E. & De Yoreo, J. J.
Object Type: Article
System: The UNT Digital Library
Accelerator mass spectrometry of actinides (open access)

Accelerator mass spectrometry of actinides

None
Date: June 9, 2005
Creator: Marchetti, A. A.; Brown, T. A.; Cox, C. C.; Hamilton, T. F. & Martinelli, R. E.
Object Type: Article
System: The UNT Digital Library
Acoustic Monitor for Liquid-Solid Slurries Measurements at Low Weight Fractions (open access)

Acoustic Monitor for Liquid-Solid Slurries Measurements at Low Weight Fractions

Our effort in this project is to develop an acoustic monitor for accurate, real-time characterization of the size and weight fractions of solids in slurries for process monitoring and to determine the optimal timing for slurry transfers. This capability will be valuable in the Savannah River Site accelerated clean-up program. Our scientific work during the first research period developed a theory, supported by experiments, to describe sound attenuation of solids in suspensions in the presence of bubbles, which permits us to determine the solid-liquid weight percent. Engineering developments during the second research period led to the design, construction, and demonstration, in our laboratories, of the Syracuse Acoustic Monitor (SAM) system that measures weight percent solids accurately in slurries of 0.5 to 8.0 weight percent on-line and in real-time. Also, we had shown the potential for these measurements in solid-gas-liquid slurries by removing the interference due to the presence of gas bubbles.
Date: June 1, 2005
Creator: Tavlarides, Lawrence L.
Object Type: Report
System: The UNT Digital Library
Acoustic Monitor for Liquid-Solid Slurries Measurements at Low Weight Fractions (open access)

Acoustic Monitor for Liquid-Solid Slurries Measurements at Low Weight Fractions

Our effort in this project is to develop an acoustic monitor for accurate, real-time characterization of the size and weight fractions of solids in slurries for process monitoring and to determine the optimal timing for slurry transfers. This capability will be valuable in the Savannah River Site accelerated clean-up program. Our scientific work during the first research period developed a theory, supported by experiments, to describe sound attenuation of solids in suspensions in the presence of bubbles, which permits us to determine the solid-liquid weight percent. Engineering developments during the second research period led to the design, construction, and demonstration, in our laboratories, of the Syracuse Acoustic Monitor (SAM) system that measures weight percent solids accurately in slurries of 0.5 to 8.0 weight percent on-line and in real-time. Also, we had shown the potential for these measurements in solid-gas-liquid slurries by removing the interference due to the presence of gas bubbles.
Date: June 1, 2005
Creator: Taviarides, Lawrence L.
Object Type: Report
System: The UNT Digital Library
An Active Region Model for Capturing Fractal Flow Patterns inUnsaturated Soils: Model Development (open access)

An Active Region Model for Capturing Fractal Flow Patterns inUnsaturated Soils: Model Development

Preferential flow commonly observed in unsaturated soils allows rapid movement of solute from the soil surface or vadose zone to the groundwater, bypassing a significant volume of unsaturated soil and increasing the risk of groundwater contamination. A variety of evidence indicates that complex preferential patterns observed from fields are fractals. In this study, we developed a relatively simple active region model to incorporate the fractal flow pattern into the continuum approach. In the model, the flow domain is divided into active and inactive regions. Flow occurs preferentially in the active region (characterized by fractals), and inactive region is simply bypassed. A new constitutive relationship (the portion of the active region as a function of saturation) was derived. The validity of the proposed model is demonstrated by the consistency between field observations and the new constitutive relationship.
Date: June 11, 2005
Creator: Liu, Hui-Hai; Zhang, R. & Bodvarsson, Gudmundur S.
Object Type: Article
System: The UNT Digital Library
An Active Region Model for Capturing Fractal Flow Patterns inUnsaturated Soils: Model Development (open access)

An Active Region Model for Capturing Fractal Flow Patterns inUnsaturated Soils: Model Development

This report describes the development of a simple active region model to incorporate the fractal flow pattern into the continuum approach.
Date: June 11, 2005
Creator: Liu, Hui-Hai; Zhang, R. & Bodvarsson, Gudmundur S.
Object Type: Article
System: The UNT Digital Library
An adaptive radiation model for the origin of new gene functions (open access)

An adaptive radiation model for the origin of new gene functions

None
Date: June 14, 2005
Creator: Francino, M. Pilar
Object Type: Report
System: The UNT Digital Library
Adsorption of biometals to monosodium titanate in biological environments (open access)

Adsorption of biometals to monosodium titanate in biological environments

Monosodium titanate (MST) is an inorganic sorbent/ion exchanger developed for the removal of radionuclides from nuclear wastes. We investigated the ability of MST to bind Cd(II), Hg(II), or Au(III) to establish the utility of MST for applications in environmental decontamination or medical therapy (drug delivery). Adsorption isotherms for MST were determined at pH 7-7.5 in water or phosphate-buffered saline. The extent of metal binding was determined spectroscopically by measuring the concentrations of the metals in solution before and after contact with the MST. Cytotoxic responses to MST were assessed using THP1 monocytes and succinate dehydrogenase activity. Monocytic activation by MST was assessed by TNF{alpha} secretion (ELISA) with or without lipopolysaccharide (LPS) activation. MST sorbed Cd(II), Hg(II), and Au(III) under conditions similar to that in physiological systems. MST exhibited the highest affinity for Cd(II) followed by Hg(II) and Au (III). MST (up to 100 mg/L) exhibited only minor (< 25% suppression of succinate dehydrogenase) cytotoxicity and did not trigger TNF{alpha} secretion nor modulate LPS-induced TNF{alpha} secretion from monocytes. MST exhibits high affinity for biometals with no significant biological liabilities in these introductory studies. MST deserves further scrutiny as a substance with the capacity to decontaminate biological environments or deliver metals in …
Date: June 6, 2005
Creator: Hobbs, D. T.; Messer, R. L. W.; Lewis, J. B.; Click, D. R. Lockwood, P. E. & Wataha, J. C.
Object Type: Article
System: The UNT Digital Library
Advanced 3D Photocathode Modeling and Simulations Final Report (open access)

Advanced 3D Photocathode Modeling and Simulations Final Report

High brightness electron beams required by the proposed Next Linear Collider demand strong advances in photocathode electron gun performance. Significant improvement in the production of such beams with rf photocathode electron guns is hampered by the lack high-fidelity simulations. The critical missing piece in existing gun codes is a physics-based, detailed treatment of the very complex and highly nonlinear photoemission process.
Date: June 6, 2005
Creator: Dimitrov, Dimitre A. & Bruhwiler, David L.
Object Type: Report
System: The UNT Digital Library
Advanced Design of a Novel Stellarator Using the Free Boundary VMEC Magnetic Equilibrium Code. Final Technical Report for period March 1, 1999 - February 28, 2002 (open access)

Advanced Design of a Novel Stellarator Using the Free Boundary VMEC Magnetic Equilibrium Code. Final Technical Report for period March 1, 1999 - February 28, 2002

This report describes the goals and accomplishments of a 3-year EPSCoR Laboratory Partnership award to design an advanced stellarator device for magnetic confinement of toroidal plasmas for fusion research.
Date: June 1, 2005
Creator: Knowlton, S. F.
Object Type: Report
System: The UNT Digital Library
Advanced Gamma-Ray Detection Concepts Combined with Real-Time Compton Suppression for Nondestructive, Gamma-Ray Characterization of Remote Handled Waste (open access)

Advanced Gamma-Ray Detection Concepts Combined with Real-Time Compton Suppression for Nondestructive, Gamma-Ray Characterization of Remote Handled Waste

Nondestructive gamma ray characterization of remote-handled waste is significantly complicated by the presence of Compton scattering in the detector and waste matrix produced by intense cesium gamma rays. This research seeks to understand the photophysics of a new type of inorganic scintillation gamma ray detector, optimize the combination of this gamma ray detector with a Compton guard detector, develop new Monte Carlo solution algorithms for modeling Compton scattering in the waste, and to model the real time intensity of cesium produced Compton scattering. A successful research program will provide the fundamental information needed to design and develop advanced Compton spectrometers for assay of remote handled waste and new higher sensitivity spectrometers for environmental measurements.
Date: June 1, 2005
Creator: Mcllwain, Michael E.; Haghighat, Alireza; Dorenbos, Pieter & Hartwell, John K.
Object Type: Report
System: The UNT Digital Library
Advanced Multi-Product Coal Utilization By-Product Processing Plant (open access)

Advanced Multi-Product Coal Utilization By-Product Processing Plant

The objective of the project is to build a multi-product ash beneficiation plant at Kentucky Utilities 2,200-MW Ghent Generating Station, located in Carroll County, Kentucky. This part of the study includes the examination of the feedstocks for the beneficiation plant. The ash, as produced by the plant, and that stored in the lower pond were examined. Filter media candidates were evaluated for dewatering the ultrafine ash (UFA) product. Media candidates were selected based on manufacturer recommendations and evaluated using standard batch filtration techniques. A final media was selected; 901F, a multifilament polypropylene. While this media would provide adequate solids capture and cake moisture, the use of flocculants would be necessary to enable adequate filter throughput. Several flocculant chemistries were also evaluated and it was determined that polyethylene oxide (PEO) at a dosage of 5 ppm (slurry basis) would be the most suitable in terms of both settling rate and clarity. PEO was evaluated on a continuous vacuum filter using 901F media. The optimum cycle time was found to be 1.25 minutes which provided a 305% moisture cake, 85% solids capture with a throughput of 115 lbs dry solids per hour and a dry cake rate of 25 lb/ft2/hr. Increasing cycle …
Date: June 1, 2005
Creator: Groppo, John & Robl, Thomas
Object Type: Report
System: The UNT Digital Library
Advanced Techniques for In-Situ Monitoring of Phase Transformations During Welding Using Synchrotron-Based X-Ray Diffraction (open access)

Advanced Techniques for In-Situ Monitoring of Phase Transformations During Welding Using Synchrotron-Based X-Ray Diffraction

Understanding the evolution of microstructure in welds is an important goal of welding research because of the strong correlation between weld microstructure and weld properties. To achieve this goal it is important to develop a quantitative measure of phase transformations encountered during welding in order to ultimately develop methods for predicting weld microstructures from the characteristics of the welding process. To aid in this effort, synchrotron radiation methods have been developed at Lawrence Livermore National Laboratory (LLNL) for direct observation of microstructure evolution during welding. Using intense, highly collimated synchrotron radiation, the atomic structure of the weld heat affected and fusion zones can be probed in real time. Two synchrotron-based techniques, known as spatially resolved (SRXRD) and time resolved (TRXRD) x-ray diffraction, have been developed for these investigations. These techniques have now been used to investigate welding induced phase transformations in titanium alloys, low alloy steels, and stainless steel alloys. This paper will provide a brief overview of these methods and will discuss microstructural evolution during the welding of low carbon (AISI 1005) and medium carbon (AISI 1045) steels where the different levels of carbon influence the evolution of microstructures during welding.
Date: June 5, 2005
Creator: Elmer, J. W.; Palmer, T. A.; Zhang, W. & DebRoy, T.
Object Type: Article
System: The UNT Digital Library
Advances in Normal Conducting Accelerator Technology from the X-Band Linear Collider Program (open access)

Advances in Normal Conducting Accelerator Technology from the X-Band Linear Collider Program

In the mid-1990's, groups at SLAC and KEK began dedicated development of X-band (11.4 GHz) rf technology for a next generation, TeV-scale linear collider. The choice of a relatively high frequency, four times that of the SLAC 50 GeV Linac, was motivated by the cost benefits of having lower rf energy per pulse (hence fewer rf sources) and reasonable efficiencies at high gradients (hence shorter linacs). To realize such savings, however, requires operation at gradients and peak powers much higher than that hitherto achieved. During the past twelve years, these challenges were met through innovations on several fronts. This paper reviews these achievements, which include developments in the generation and transport of high power rf, and new insights into high gradient limitations.
Date: June 22, 2005
Creator: Adolphsen, C.
Object Type: Article
System: The UNT Digital Library
Advances in Target Design for Heavy-Ion Fusion (open access)

Advances in Target Design for Heavy-Ion Fusion

Over the past few years, the emphasis in heavy ion target design has moved from the distributed radiator target to the 'hybrid' target because the hybrid target allows a larger beam focal spot than the distributed radiator ({approx} 5 mm radius rather than {approx} 2 mm radius). The larger spot relaxes some of the requirements on the driver, but introduces some new target physics issues. Most notable is the use of shine shields and shims in the hohlraum to achieve symmetry rather than achieving symmetry by beam placement. The shim is a thin layer of material placed on or near the capsule surface to block a small amount of excess radiation. While we have been developing this technique for the heavy ion hybrid target, the technique can be used in any indirect drive target. We have begun testing the concept of a shim to improve symmetry using a double-ended z-pinch hohlraum on the Sandia Z-machine. Experiments using shimmed thin wall capsules have shown that we can reverse the sign of a P{sub 2} asymmetry and significantly reduce the size of a P{sub 4} asymmetry. These initial experiments demonstrate the concept of a shim as another method for controlling early time …
Date: June 21, 2005
Creator: Callahan, D. A.; Tabak, M.; Bennett, G. R.; Cuneo, M. E.; Vesey, R. A.; Nikroo, A. et al.
Object Type: Article
System: The UNT Digital Library
ADVANCES TOWARDS THE MEASUREMENT AND CONTROL LHC TUNE AND CHROMATICITY (open access)

ADVANCES TOWARDS THE MEASUREMENT AND CONTROL LHC TUNE AND CHROMATICITY

Requirements for tune and chromaticity control in most superconducting hadron machines, and in particular the LHC, are stringent. In order to reach nominal operation, the LHC will almost certainly require feedback on both tune and chromaticity. Experience at RHIC has also shown that coupling control is crucial to successful tune feedback. A prototype baseband phase-locked loop (PLL) tune measurement system has recently been brought into operation at RHIC as part of the US LHC Accelerator Research Program (LARP). We report on the performance of that system and compare it with the extensive accumulation of data from the RHIC 245MHz PLL.
Date: June 6, 2005
Creator: Cameron, P.; Cupolo, J.; Degen, C.; Dellapenna, A.; Hoff, L.; Mead, J. et al.
Object Type: Article
System: The UNT Digital Library