2005 Chemical Reactions at Surfaces (open access)

2005 Chemical Reactions at Surfaces

The Gordon Research Conference (GRC) on 2005 Chemical Reactions at Surfaces was held at Ventura Beach Marriott, Ventura California from February 13, 2005 through February 18, 2005. The Conference was well-attended with 124 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. In designing the formal speakers program, emphasis was placed on current unpublished research and discussion of the future target areas in this field. There was a conscious effort to stimulate lively discussion about the key issues in the field today. Time for formal presentations was limited in the interest of group discussions. In order that more scientists could communicate their most recent results, poster presentation time was scheduled. Attached is a copy of the formal schedule and speaker program and the poster program. In addition to these formal interactions, 'free time' was scheduled to allow informal discussions. Such discussions are fostering new collaborations and joint efforts in the field.
Date: March 14, 2006
Creator: Friend, Cynthia M.
System: The UNT Digital Library
2nd Annual DOE-ERSP PI Meeting: Abstracts (open access)

2nd Annual DOE-ERSP PI Meeting: Abstracts

Welcome to the annual 2007 Environmental Remediation Sciences Program (ERSP) Principal Investigators (PIs) meeting. The purpose of this meeting is to bring together all of the lead PIs and key Co-PIs in the program to share and review the results of funded research from the past year. This meeting allows program managers from the Environmental Remediation Sciences Division (ERSD) within the Office of Biological and Environmental Research (OBER) to gauge the progress and significance of the funded research, and it is also an important venue to showcase ERSP research to interested parties within DOE and other invited federal agency representatives. Additionally, these meetings should serve as an opportunity for funded PIs to view their research in the context of the entire ERSP portfolio. Past ERSP meetings have been very important venues for detailed discussion of research results among PIs, development of new research ideas, fostering new collaborations and discussion with ERSD program managers on future research efforts and/or initiatives within the program. In short, these meetings are an important resource for both program managers and PIs. There will be only one ERSP PI meeting for 2007. In years past, ERSD has sponsored two PI meetings, one in the spring and …
Date: March 14, 2007
Creator: Hazen, Terry C.
System: The UNT Digital Library
Ancient and Modern Laminated Composites - From the Great Pyramid of Gizeh to Y2K (open access)

Ancient and Modern Laminated Composites - From the Great Pyramid of Gizeh to Y2K

Laminated metal composites have been cited in antiquity; for example, a steel laminate that may date as far back as 2750 B.C., was found in the Great Pyramid in Gizeh in 1837. A laminated shield containing bronze, tin, and gold layers, is described in detail by Homer. Well-known examples of steel laminates, such as an Adze blade, dating to 400 B.C. can be found in the literature. The Japanese sword is a laminated composite at several different levels and Merovingian blades were composed of laminated steels. Other examples are also available, including composites from China, Thailand, Indonesia, Germany, Britain, Belgium, France, and Persia. The concept of lamination to provide improved properties has also found expression in modern materials. Of particular interest is the development of laminates including high carbon and low carbon layers. These materials have unusual properties that are of engineering interest; they are similar to ancient welded Damascus steels. The manufacture of collectable knives, labeled ''welded Damascus'', has also been a focus of contemporary knifemakers. Additionally, in the Former Soviet Union, laminated composite designs have been used in engineering applications. Each of the above areas will be briefly reviewed, and some of the metallurgical principles will be described …
Date: March 14, 2000
Creator: Wadsworth, J. & Lesuer, D. R.
System: The UNT Digital Library
Assessing the disturbed rock zone (DRZ) around a 655 meter vertical shaft in salt using ultrasonic waves: An update (open access)

Assessing the disturbed rock zone (DRZ) around a 655 meter vertical shaft in salt using ultrasonic waves: An update

An array of ultrasonic transducers was constructed consisting of three identical arrays at various depths in an air intake shaft at the Waste Isolation Pilot Plant (WIPP). Each array consists of transducers permanently installed in three holes arranged in an L shape. An active array, created by appropriate arrangement of the transducers and selection of transmitter-receiver pairs, allows the measurement of transmitted signal velocities and amplitudes (for attenuation studies) along 216 paths parallel, perpendicular and tangential to the shaft walls. Transducer positions were carefully surveyed, allowing absolute velocity measurements. Installation occurred over a period of about two years beginning in early 1989, with nearly continuous operation since that time, resulting in a rare, if not unique, record of the spatial and temporal variability of damage development around an underground opening. This paper reports results from the last two years of operation, updating the results reported by Holcomb, 1999. Results will be related to the damage, due to microcracking, required to produce the observed changes. It is expected that the results will be useful to other studies of the long-term deformation characteristics of salt.
Date: March 14, 2000
Creator: HARDY,ROBERT D. & HOLCOMB,DAVID J.
System: The UNT Digital Library
Assessment of Ivanpah Playa as a Site for Thermal Vicarious Calibration for the MTI Satellite (open access)

Assessment of Ivanpah Playa as a Site for Thermal Vicarious Calibration for the MTI Satellite

The Savannah River Technology Center conducted four vicarious reflectance calibrations at Ivanpah Playa, California since July 2000 in support of the MTI satellite. The potential of the playa as a thermal calibration site was also investigated in the campaigns with a mobile Fourier transform infrared spectrometer. The multi-year study shows time and spatial variability in the spectral emissivity. The ground truth temperature and emissivity correlate quite well with the data from the MTI satellite imagery. The research paper will show the time-dependent emissivities measured during our ground truth campaigns and the corresponding satellite imagery.
Date: March 14, 2003
Creator: Villa-Aleman, E.
System: The UNT Digital Library
B0 to K0K0bar and Other Hadronic b to d Decays (open access)

B0 to K0K0bar and Other Hadronic b to d Decays

The b {yields} d penguin-dominated modes B {yields} K{bar K} have been observed at the B factories. in addition, the BABAR collaboration has reported the first time-dependent CP-violation measurement in B{sup 0} {yields} K{sup 0}{bar K}{sup 0}.
Date: March 14, 2007
Creator: Biesiada, J.
System: The UNT Digital Library
Beam Test Proposal of An ODR Beam Size Monitor at the SLAC FFTB (open access)

Beam Test Proposal of An ODR Beam Size Monitor at the SLAC FFTB

ODR (Optical Diffraction Radiation) transverse beam size measurement at the SLAC FFTB at 28.5 GeV is a challenge and it requires special target and optics system, which is much difficult than the conventional ODR beam size measurement. We propose to use a curved disphased conductive slit target to recover the sensitivity in the measurement of the single bunch transverse beam size by using ODR photons from a conductive slit. In order to cancel the effect of the beam divergence, the conductive slit target surface must be curved. Also, we can obtain the focused interference pattern of the ODR photons at the detector at the shorter distance from the target than the {gamma}{sup 2}{lambda}, by using lens optics system.
Date: March 14, 2006
Creator: Fukui, Y.; Cline, D.; Zhou, F.; /UCLA; Aryshev, A.; Karataev, P. et al.
System: The UNT Digital Library
A Cartesian grid embedded boundary method for the heat equation on irregular domains (open access)

A Cartesian grid embedded boundary method for the heat equation on irregular domains

We present an algorithm for solving the heat equation on irregular time-dependent domains. It is based on the Cartesian grid embedded boundary algorithm of Johansen and Colella (J. Comput. Phys. 147(2):60--85) for discretizing Poisson's equation, combined with a second-order accurate discretization of the time derivative. This leads to a method that is second-order accurate in space and time. For the case where the boundary is moving, we convert the moving-boundary problem to a sequence of fixed-boundary problems, combined with an extrapolation procedure to initialize values that are uncovered as the boundary moves. We find that, in the moving boundary case, the use of Crank--Nicolson time discretization is unstable, requiring us to use the L{sub 0}-stable implicit Runge--Kutta method of Twizell, Gumel, and Arigu.
Date: March 14, 2001
Creator: McCorquodale, Peter; Colella, Phillip & Johansen, Hans
System: The UNT Digital Library
Charm Results on CP Violation and Mixing (open access)

Charm Results on CP Violation and Mixing

The most recent results on CP violation and mixing in the charm system are reviewed as a guide to the future. While no surprising results are reported so far, charm provides a unique window to physics beyond the Standard Model. The results reported here come from four sources, ALEPH at LEP, E791 and FOCUS/E831 at Fermilab, and CLEO II.V at CESR. Results beyond these sources may be expected as a byproduct of B-motivated experiments.
Date: March 14, 2000
Creator: Appel, J. A.
System: The UNT Digital Library
Cloud Optical Depths and Liquid Water Paths at the NSA CART (open access)

Cloud Optical Depths and Liquid Water Paths at the NSA CART

Cloud optical depths have been measured using multifilter rotating shadowband radiometers (MFRSRs) at Barrow and Atqasuk, and liquid water paths have been measured at Barrow using a microwave radiometer (MWR) during the warm season (June-September) in 1999. Comparisons have been made between these quantities and the corresponding ones determined from the ECMWF GCM. Hour-by-hour comparisons of cloud optical depths show considerable scatter. The scatter is reduced, but is still substantial, when the averaging period is increased to ''daily'' averages, i.e., the time period each day over which the MFRSR can make measurements. This period varied between 18 hours in June and 6 hours in September. Preliminary results indicate that, for measured cloud optical depths less than approximately 25, the ECMWF has a low bias in its predictions, consistent with a low bias in predicted liquid water path. Based on a more limited set of data, the optical depths at Atqasuk were found to be generally lower than those at Barrow, a trend at least qualitatively captured by the ECMWF model. Analyses to identify the cause of the biases and the considerable scatter in the predictions are continuing.
Date: March 14, 2000
Creator: Doran, J. C.; Barnard, James C.; Zhong, Shiyuan & Jakob, C J.
System: The UNT Digital Library
Comparison of Convection Characteristics at the Tropical Western Pacific Darwin Site Between Observation and Global Climate Models Simulations (open access)

Comparison of Convection Characteristics at the Tropical Western Pacific Darwin Site Between Observation and Global Climate Models Simulations

One of the scientific objectives of the ARM Tropical Warm Pool International Cloud Experiment (TWPICE) planned for early 2006 at Darwin, Australia is to describe convection characteristics and its interaction with the large-scale fields. In view of the short duration of the experiment, it is important to determine the long-term statistics of convection and its associated clouds from the observations and global climate models (GCM) so as to put the experiment results in proper climate perspective. For this purpose, we examine several important fields associated with the characteristics of convection and the relationships between convection and clouds using GCM simulations and available satellite and surface observations. These include the seasonal variation of convection, the relationships between convection and the upper-level cloud amount, cloud ice water content and cloud radiative forcing. One major goal of the ARM program is to improve GCM cloud and convection parameterizations. Using NCAR Community Atmosphere Model (CAM3), we demonstrate that GCM simulations in the tropical western Pacific including Darwin can be significantly improved by improving convection parameterization.
Date: March 14, 2005
Creator: Zhang, G. J.
System: The UNT Digital Library
Criticality control in shipments of fissile materials (open access)

Criticality control in shipments of fissile materials

This paper describes a procedure for finite-array criticality analysis to ensure criticality safety of shipments of fissile materials in US DOE-certified packages. After the procedure has been performed, one can obtain the minimum transport index and determine the maximum number of fissile packages allowable in a shipment that meets the 10 CFR 71 criticality safety requirements.
Date: March 14, 2000
Creator: Liaw, J. R. & Liu, Y. Y.
System: The UNT Digital Library
Criticality safety requirements for transporting EBR-II fuel bottles stored at INTEC (open access)

Criticality safety requirements for transporting EBR-II fuel bottles stored at INTEC

Two carrier/shipping cask options are being developed to transport bottles of EBR-II fuel elements stored at INTEC. Some fuel bottles are intact, but some have developed leaks. Reactivity control requirements to maintain subcriticality during the hypothetical transport accident have been examined for both transport options for intact and leaking bottles. Poison rods, poison sleeves, and dummy filler bottles were considered; several possible poison materials and several possible dummy filler materials were studied. The minimum number of poison rods or dummy filler bottles has been determined for each carrier for transport of intact and leaking bottles.
Date: March 14, 2000
Creator: Lell, R. M. & Pope, C. L.
System: The UNT Digital Library
CuPt-type ordering of MOCVD In{sub 0.49}Al{sub 0.51}P. (open access)

CuPt-type ordering of MOCVD In{sub 0.49}Al{sub 0.51}P.

CuPt-type ordering in In{sub 0.49}Al{sub 0.51}P is studied by TEM. The lattice-matched film was grown by MOCVD on a GaAs substrate oriented 10{sup o} off (001) towards [110], at 650 C and 25 nm/min. TEM [110] and [1{bar 1}0] cross-sections (XS) were made by wedge polishing and 2 kV Ar ion milling. In CuPt-type ordering of In{sub 0.52}Ga{sub 0.48}P, alternating In-Ga-In-Ga {l_brace}111{r_brace} planes of group III atoms produce 1/2 {bar 1}11 and 1/2 1{bar 1}1 order spots in the 110 SADP, while the [1{bar 1}0] SADP shows no order spots [1-3]. A few studies have reported this type of order in In{sub 0.49}Al{sub 0.51}P [4]. The 004 BF image of the [1{bar 1}0] XS in Fig. 1 shows uneven light/dark contrast modulation due to phase separation often observed in In{sub 0.52}Ga{sub 0.48}P. There are also light/dark layers marked ML parallel to the film growth plane; such unintentional multilayers have also been observed [5] but their origin is not understood. Order lamellae {approx}1.5 nm thick inclined at a shallow angle to the growth plane overlap the multilayer to produce Moire fringe contrast. Fig. 2 is a DF image showing the thin ordered domains in the [1{bar 1}0] XS, which are inclined …
Date: March 14, 2002
Creator: Kosel, T. H.; Hall, D. C.; Dupuis, R. D.; Heller, R. D. & Cook, R. E.
System: The UNT Digital Library
Density and Tensile Properties Changed by Aging Plutonium (open access)

Density and Tensile Properties Changed by Aging Plutonium

We present volume, density, and tensile property change observed from both naturally and accelerated aged plutonium alloys. Accelerated alloys are plutonium alloys with a fraction of Pu-238 to accelerate the aging process by approximately 18 times the rate of unaged weapons-grade plutonium. After thirty-five equivalent years of aging on accelerated alloys, the dilatometry shows the samples at 35 C have swelled in volume by 0.12 to 0.14% and now exhibit a near linear volume increase due to helium in-growth while showing possible surface effects on samples at 50 C and 65 C. The engineering stress of the accelerated alloy at 18 equivalent years increased significantly compared to at 4.5 equivalent years.
Date: March 14, 2005
Creator: Chung, B. W.; Choi, B. W.; Thompson, S. R.; Woods, C. H.; Hopkins, D. J. & Ebbinghaus, B. B.
System: The UNT Digital Library
Density Variations in IHE Formulations Due to Thermal Cycling (open access)

Density Variations in IHE Formulations Due to Thermal Cycling

Thermal cycling was used as a means to control density in the preparation of Insensitive High Explosive (IHE) specimens slated for performance testing. These samples were thermally cycled between -55 degrees C and 70 degrees C and their densities measured using hydrostatic weighing, an immersion density measurement technique. Bulk sample densities were reduced by as much as 1.5% over 40 thermal cycles. In these thermal cycling studies, the effects of several parameters were investigated. These parameters included different ME composites (LX-17 and PBX 9502), different pressing mechanisms (die-pressed and isostatically-pressed) and sample size.
Date: March 14, 2002
Creator: Lewis, P; Cunningham, B; De Teresa, S; Harwood, P & Tran, T
System: The UNT Digital Library
Design and characterization of a neutralized-transport experiment for heavy-ion fusion (open access)

Design and characterization of a neutralized-transport experiment for heavy-ion fusion

In heavy-ion inertial-confinement fusion systems, intense beams of ions must be transported from the exit of the final focus magnet system through the fusion chamber to hit millimeter-sized spots on the target. Effective plasma neutralization of intense ion beams in this final transport is essential for a heavy-ion fusion power plant to be economically competitive. The physics of neutralized drift has been studied extensively with particle-in-cell simulations. To provide quantitative comparisons of theoretical predictions with experiment, the Virtual National Laboratory for Heavy Ion Fusion has completed the construction and has begun experimentation with the Neutralized Transport Experiment (NTX). The experiment consists of three main sections, each with its own physics issues. The injector is designed to generate a very high-brightness, space-charge-dominated potassium beam while still allowing variable perveance by a beam aperturing technique. The magnetic-focusing section, consisting of four pulsed magnetic quadrupoles, permits the study of beam tuning, as well as the effects of phase space dilution due to higher-order nonlinear fields. In the final section, the converging ion beam exiting the magnetic section is transported through a drift region with plasma sources for beam neutralization, and the final spot size is measured under various conditions of neutralization. In this …
Date: March 14, 2004
Creator: Henestroza, E.; Eylon, S.; Roy, P. K.; Yu, S. S.; Anders, A.; Bieniosek, F. M. et al.
System: The UNT Digital Library
Effect of Internal Alpha Radiation on Borosilicate Glass Containing Simulated Radioactive Waste (open access)

Effect of Internal Alpha Radiation on Borosilicate Glass Containing Simulated Radioactive Waste

To evaluate borosilicate glass as a matrix for long-term storage of radioactive waste, samples containing 45 wt. percent simulated waste along with 0.5 wt. percent 244Cm or 1 wt. percent 238Pu as alpha particle emitters were synthesized. A glass containing 238Pu without simulated waste was also made. Effects of internal alpha radiolysis from 244Cm and 238Pu on physical stability, leachability, and dilatation of the glasses were examined. Results confirm that glass may be a desirable matrix for fixing SRP radioactive waste for long-term storage. Internal alpha radiolysis and helium accumulation in the small samples did not significantly damage the glass. Actual values for helium solubility and permeability would be necessary, however, to determine whether helium accumulation might eventually damage larger glass monoliths during long-term storage.
Date: March 14, 2001
Creator: Bibler, N.E.
System: The UNT Digital Library
Effect of oxygen on the electronic band structure in ZnO{sub x}Se{sub 1-x} alloys (open access)

Effect of oxygen on the electronic band structure in ZnO{sub x}Se{sub 1-x} alloys

The effect of alloying small amounts of ZnO with ZnSe on the electronic band structure has been studied. Optical transitions in molecular-beam-epitaxy-grown ZnO{sub x}Se{sub 1-x} epitaxial films (0 {<=} x {<=} 1.35%) were investigated using photoreflectance and photoluminescence spectroscopies. The fundamental band-gap energy of the alloys was found to decrease at a rate of about 0.1 eV per atomic percent of oxygen. The pressure dependence of the band gap was also found to be strongly affected by O incorporation. Both the effects can be quantitatively explained by an anticrossing interaction between the extended states of the conduction band of ZnSe and the highly localized oxygen states located at approximately 0.22 eV above the conduction-band edge.
Date: March 14, 2003
Creator: Shan, W.; Walukiewicz, W.; Ager, J. W., III; Yu, K. M.; Wu, J.; Haller, E. E. et al.
System: The UNT Digital Library
The Effect of Thermo-mechanical Processing on the Mechanical Properties of Molybdenum-2 Volume%Lanthana (open access)

The Effect of Thermo-mechanical Processing on the Mechanical Properties of Molybdenum-2 Volume%Lanthana

Variations in oxide species and consolidation method have been shown to have a significant effect on the mechanical properties of oxide dispersion strengthened (ODS) molybdenum material. The mechanical behavior of molybdenum - 2 Volume % La[sub]2O[sub]3 mill product forms, produced by a wet doping process, were characterized over the temperature range of -150 degrees C to 1800 degrees C. The various mill product forms evaluated ranged from thin sheet stock to bar stock. Tensile properties of the material in the various product forms were not significantly affected by the vast difference in total cold work. Creep properties, however, were sensitive to the total amount of cold work as well as the starting microstructure. Stress-relieved material had superior creep rupture properties to recrystallized material at 1200 degrees C, while at 1500 degrees C and above the opposite was observed. Thus it is necessary to match the appropriate thermo-mechanical processing and microstructure of molybdenum - 2 volume % LA[sub]2O[sub]3 to the demands of the application being considered.
Date: March 14, 2001
Creator: Mueller, A. J.; Buckman, R. W., Jr. & Shields, A. J., Jr
System: The UNT Digital Library
Elevated stratified layers observed during VTMX. (open access)

Elevated stratified layers observed during VTMX.

A suite of instrumentation including a minisodar, a low-frequency, single-axis sodar, a wind profiling radar and a tethersonde was used during the Vertical Transport and Mixing field study in Salt Lake City, UT, USA, to study the evolution and dynamics of stratified layers that commonly develop during nighttime. The month-long field study provided ten nights with good conditions for tethersonde flights. The real-time sodar display was used to place the tethersonde within and near the stratified layers and to make multiple transects, while atmospheric temperature, moisture, wind speed and wind direction were measured. Not surprisingly, the existence of layers with enhanced acoustic scattering correlated well with regions of potential temperature inversions; however, because wind speeds were invariably low, the Richardson number was rarely less than 0.25. The possible role of moisture in the dynamics of elevated stable layer is discussed.
Date: March 14, 2002
Creator: Coulter, R. L.; Pekour, M. S. & Martin, T. J.
System: The UNT Digital Library
Energy Doubling of 42 GeV Electrons in a Meter-scale Plasma Wakefield Accelerator (open access)

Energy Doubling of 42 GeV Electrons in a Meter-scale Plasma Wakefield Accelerator

The energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant energy gain. Here we show that an energy gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx} 52GV m{sup -1}. This effectively …
Date: March 14, 2007
Creator: Blumenfeld, Ian; Clayton, Christopher E.; Decker, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus et al.
System: The UNT Digital Library
An Evaluation of Two Advanced Turbulence Models for Simulating the Flow and Dispersion Around Buildings (open access)

An Evaluation of Two Advanced Turbulence Models for Simulating the Flow and Dispersion Around Buildings

Numerical modeling of airflow and pollutant dispersion around buildings is a challenging task due to the geometrical variations of buildings and the extremely complex flow created by such surface-mounted obstacles. The airflow around buildings inevitably involves impingement and separation regions, building wakes with multiple vortices, and jetting effects in street canyons. The interference from adjacent buildings further complicates the flow and dispersion patterns. Thus accurate simulations of building-scale transport phenomena requires not only appropriate physics submodels but also significant computing resources. They have developed an efficient, high resolution CFD model for simulating chemical and biological releases around buildings. The primary goal is to support incident response and preparedness in emergency response planning and vulnerability analysis.
Date: March 14, 2000
Creator: Chan, S. T. & Stevens, D. E.
System: The UNT Digital Library
First NNLL Prediction of B(\barB \rightarrow X_s \gamma) (open access)

First NNLL Prediction of B(\barB \rightarrow X_s \gamma)

The authors discuss the first NNLL prediction of the B {yields} X{sub s}{gamma} branching ratio, including important additional subtleties due to non-perturbative corrections and logarithmically-enhanced cut effects.
Date: March 14, 2007
Creator: Hurth, Tobias & /SLAC, /CERN
System: The UNT Digital Library