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Space-time thermodynamics of the glass transition (open access)

Space-time thermodynamics of the glass transition

We consider the probability distribution for the fluctuations in the dynamical action of glass forming materials. We argue that the so-called glass transition is a manifestation of low action tails in these distributions where the entropy of trajectory space is sub-extensive in time. These low action tails are a consequence of dynamic heterogeneity and an indication of phase coexistence in trajectory space. The glass transition, where the system falls out of equilibrium, is then an order-disorder phenomenon in space-time occurring at a temperature T{sub g} which is a weak function of measurement time. We illustrate our perspective ideas with facilitated lattice models, and note how these ideas apply more generally.
Date: January 31, 2005
Creator: Merolle, Mauro; Garrahan, Juan P. & Chandler, David
System: The UNT Digital Library
Simulating Electron Cloud Effects in Heavy-Ion Beams (open access)

Simulating Electron Cloud Effects in Heavy-Ion Beams

None
Date: January 24, 2005
Creator: Cohen, R H; Friedman, A; Lund, S M; Molvik, A W; Azevedo, T; Vay, J et al.
System: The UNT Digital Library
ASM News Volume 71 Number 9, 2005 (open access)

ASM News Volume 71 Number 9, 2005

Genetic exchanges among prokaryotes, formerly considered only a marginal phenomenon, increasingly are being viewed as profoundly affecting evolution. Indeed, some researchers argue for utterly revamping our concept of microbial speciation and phylogeny by replacing the traditional ''tree'' with a newer ''net'' to account for these horizontal transfers of genes. This conceptual ferment is occurring while molecular biologists reveal how horizontal gene transfers occur even as microbes protect the integrity of their genomes. Other studies reveal the number and diversity and abundance of genetic elements that mediate horizontal gene transfers (HGTs) or facilitate genome rearrangements, deletions, and insertions. Taken together, this information suggests that microbial communities collectively possess a dynamic gene pool, where novel genetic combinations act as a driving force in genomic innovation, compensating individual microbial species for their inability to reproduce sexually. These microbial genomic dynamics can present both environmental threats and promise to humans. One major threat, for example, comes from the spread of antibiotic resistance and virulence genes among pathogenic microbes. Another less-documented issue involves transgenic plants and animals, whose uses are being restricted because of concerns that genes may be transferred to untargeted organisms where they might cause harm. A possible benefit from HGT comes from …
Date: January 1, 2005
Creator: Smets, Tamar Barkay and Barth F.
System: The UNT Digital Library
Corrosion probes for fireside monitoring in coal-fired boilers (open access)

Corrosion probes for fireside monitoring in coal-fired boilers

Corrosion probes are being developed and combined with an existing measurement technology to provide a tool for assessing the extent of corrosion of metallic materials on the fireside in coal-fired boilers. The successful development of this technology will provide power plant operators the ability to (1) accurately monitor metal loss in critical regions of the boiler, such as waterwalls, superheaters, and reheaters; and (2) use corrosion rates as process variables. In the former, corrosion data could be used to schedule maintenance periods and in the later, processes can be altered to decrease corrosion rates. The research approach involves laboratory research in simulated environments that will lead to field tests of corrosion probes in coal-fired boilers. Laboratory research has already shown that electrochemically-measured corrosion rates for ash-covered metals are similar to actual mass loss corrosion rates. Electrochemical tests conducted using a potentiostat show the corrosion reaction of ash-covered probes at 500?C to be electrochemical in nature. Corrosion rates measured are similar to those from an automated corrosion monitoring system. Tests of corrosion probes made with mild steel, 304L stainless steel (SS), and 316L SS sensors showed that corrosion of the sensors in a very aggressive incinerator ash was controlled by the …
Date: January 1, 2005
Creator: Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, M. & Holcomb, Gordon R.
System: The UNT Digital Library
Simulating Electron Clouds in Heavy-Ion Accelerators (open access)

Simulating Electron Clouds in Heavy-Ion Accelerators

None
Date: January 20, 2005
Creator: Cohen, R H; Friedman, A; Covo, M K; Lund, S M; Molvik, A W; Bieniosek, F M et al.
System: The UNT Digital Library
ENAM'04 Fourth International Conference on Exotic Nuclei and Atomic Masses (open access)

ENAM'04 Fourth International Conference on Exotic Nuclei and Atomic Masses

The conference can trace its origins to the 1950s and 1960s with the Atomic Mass and Fundamental Constants (AMCO) and the Nuclei Far From Stability (NFFS) series of conferences. Held jointly in 1992, the conferences officially merged in 1995 and the fourth conference was held at Callaway Gardens in Pine Mountain, GA and was organized by the Physics Division at Oak Ridge National Laboratory. The conference covered a broad list of topics consisting of a series of invited and contributed presentation highlighting recent research in the following fields: Atomic masses, nuclear moments, and nuclear radii; Forms of radioactivity; Nuclear structure, nuclei at the drip lines, cluster phenomena; Reactions with radioactive ion beams; Nuclear astrophysics; Fundamental symmetries and interactions; Heaviest elements and fission; Radioactive ion beam production and experimental developments; Applications of exotic nuclei
Date: January 1, 2005
Creator: Gross, C. J.; Nazarewicz, W. & Rykaczewski, K. P.
System: The UNT Digital Library
Hot topics in flavor physics at CDF (open access)

Hot topics in flavor physics at CDF

Hot topics in flavor physics at CDF are reviewed. Selected results of top, beauty, charm physics and exotic states in about 200 pb{sup -1} data collected by the CDF II detector in p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron are presented.
Date: January 1, 2005
Creator: Jun, Soon Yung
System: The UNT Digital Library
Radiation Diffusion: An Overview of Physical and Numerical Concepts (open access)

Radiation Diffusion: An Overview of Physical and Numerical Concepts

An overview of the physical and mathematical foundations of radiation transport is given. Emphasis is placed on how the diffusion approximation and its transport corrections arise. An overview of the numerical handling of radiation diffusion coupled to matter is also given. Discussions center on partial temperature and grey methods with comments concerning fully implicit methods. In addition finite difference, finite element and Pert representations of the div-grad operator is also discussed
Date: January 14, 2005
Creator: Graziani, F R
System: The UNT Digital Library
Uranium passivation by C+ implantation: a photoemission and secondary ion mass spectrometry study (open access)

Uranium passivation by C+ implantation: a photoemission and secondary ion mass spectrometry study

Implantation of 33 keV C{sup +} ions into polycrystalline U{sup 238} with a dose of 4.3 x 10{sup 17} cm{sup -2} produces a physically and chemically modified surface layer that prevents further air oxidation and corrosion. X-ray photoelectron spectroscopy and secondary ion mass spectrometry were used to investigate the surface chemistry and electronic structure of this C{sup +} ion implanted polycrystalline uranium and a non-implanted region of the sample, both regions exposed to air for more than a year. In addition, scanning electron microscopy was used to examine and compare the surface morphology of the two regions. The U 4f, O 1s and C 1s core-level and valence band spectra clearly indicate carbide formation in the modified surface layer. The time-of-flight secondary ion mass spectrometry depth profiling results reveal an oxy-carbide surface layer over an approximately 200 nm thick UC layer with little or no residual oxidation at the carbide layer/U metal transitional interface.
Date: January 20, 2005
Creator: Nelson, A J; Felter, T E; Wu, K J; Evans, C; Ferreira, J; Siekhaus, W et al.
System: The UNT Digital Library
Radial tail resolution in the SELEX RICH (open access)

Radial tail resolution in the SELEX RICH

The authors use a 7 Million event data sample of 600 GeV/c single track pion events, where the pion track is reconstructed upstream and downstream of the SELEX RICH. They build the RICH ring radius histogram distribution and count the tail events that fall outside 5{sigma}, giving a fraction of 4 x 10{sup -5} events outside the Gaussian tails. This control of events establishes the ability of using the RICH as velocity spectrometer for high precision searches of the K{sup +} {yields} {pi}{sup +} {nu}{bar {nu}} decay like it is planned in the CKM experiment.
Date: January 1, 2005
Creator: Morelos, A.; Mata, J.; Cooper, P. S.; Engelfried, J. & Aguilera-Servin, J. L.
System: The UNT Digital Library
Stimulation Techniques Used In Enhanced Geothermal Systems: Perspectives From Geomechanics and Rock Physics (open access)

Stimulation Techniques Used In Enhanced Geothermal Systems: Perspectives From Geomechanics and Rock Physics

Understanding the processes that enhance fluid flow in crustal rocks is a key step towards extracting sustainable thermal energy from the Earth. To achieve this, geoscientists need to identify the fundamental parameters that govern how rocks respond to stimulation techniques, as well as the factors that control the evolution of permeability networks. These parameters must be assessed over variety of spatial scales: from microscopic rock properties (such as petrologic, mechanical, and diagenetic characteristics) to macroscopic crustal behavior (such as tectonic and hydro-dynamic properties). Furthermore, these factors must be suitably monitored and/or characterized over a range of temporal scales before the evolutionary behavior of geothermal fields can be properly assessed. I am reviewing the procedures currently employed for reservoir stimulation of geothermal fields. The techniques are analyzed in the context of the petrophysical characteristics of reservoir lithologies, studies of wellbore data, and research on regional crustal properties. I determine common features of geothermal fields that can be correlated to spatiotemporal evolution of reservoirs, with particular attention to geomechanics and petrophysical properties. The study of these correlations can then help guide procedures employed when targeting new prospective geothermal resources.
Date: January 1, 2005
Creator: Karner, Stephen L. & Renner, Joel
System: The UNT Digital Library
The stochastic radiative transfer equation: quantum damping, Kirchoff's law and NLTE (open access)

The stochastic radiative transfer equation: quantum damping, Kirchoff's law and NLTE

A method is presented based on the theory of quantum damping, for deriving a self consistent but approximate form of the quantum transport for photons interacting with fully ionized electron plasma. Specifically, we propose in this paper a technique of approximately including the effects of background plasma on a photon distribution function without directly solving any kinetic equations for the plasma itself. The result is a quantum Langevin equation for the photon number operator; the quantum radiative transfer equation. A dissipation term appears which is the imaginary part of the dielectric function for an electron gas with photon mediated electron-electron interactions due to absorption and re-emission. It depends only on the initial state of the plasma. A quantum noise operator also appears as a result of spontaneous emission of photons from the electron plasma. The thermal expectation value of this noise operator yields the emissivity which is exactly of the form of the Kirchoff-Planck relation. This non-zero thermal expectation value is a direct consequence of a fluctuation-dissipation relation (FDR).
Date: January 24, 2005
Creator: Graziani, F R
System: The UNT Digital Library
Lithographic measurement of EUV flare in the 0.3-NA Micro ExposureTool optic at the Advanced Light Source (open access)

Lithographic measurement of EUV flare in the 0.3-NA Micro ExposureTool optic at the Advanced Light Source

The level of flare present in a 0.3-NA EUV optic (the MET optic) at the Advanced Light Source at Lawrence Berkeley National Laboratory is measured using a lithographic method. Photoresist behavior at high exposure doses makes analysis difficult. Flare measurement analysis under scanning electron microscopy (SEM) and optical microscopy is compared, and optical microscopy is found to be a more reliable technique. In addition, the measured results are compared with predictions based on surface roughness measurement of the MET optical elements. When the fields in the exposure matrix are spaced far enough apart to avoid influence from surrounding fields and the data is corrected for imperfect mask contrast and aerial image proximity effects, the results match predicted values quite well. The amount of flare present in this optic ranges from 4.7% for 2 {micro}m features to 6.8% for 500 nm features.
Date: January 1, 2005
Creator: Cain, Jason P.; Naulleau, Patrick & Spanos, Costas J.
System: The UNT Digital Library
The low cost of geological assessment for underground CO2 storage: Policy and economic implications (open access)

The low cost of geological assessment for underground CO2 storage: Policy and economic implications

The costs for carbon dioxide (CO{sub 2}) capture and storage (CCS) in geologic formations is estimated to be $6-75/t CO{sub 2}. In the absence of a mandate to reduce greenhouse gas emissions or some other significant incentive for CCS deployment, this cost effectively limits CCS technology deployment to small niche markets and stymies the potential for further technological development through learning-by-doing until these disincentives for the free venting of CO{sub 2} are in place. By far, the largest current fraction of these costs is capture (including compression and dehydration), commonly estimated at $25-60/t CO{sub 2} for power plant applications followed by CO{sub 2} transport and storage, estimated at $0-15/t CO{sub 2}. Of the storage costs, only a small fraction of the cost will go to accurate geological characterization. These one-time costs are probably on the order of $0.1/t CO{sub 2} or less as these costs are spread out over the many millions of tons likely to be injected into a field over many decades. Geologic assessments include information central to capacity prediction, risk estimation for the target intervals, and development facilities engineering. Since assessment costs are roughly 2 orders of magnitude smaller than capture costs, and assessment products carry other …
Date: January 31, 2005
Creator: Friedmann, S J; Dooley, J; Held, H & Edenhofer, O
System: The UNT Digital Library
Analysis of the habitat of Henslow's sparrows and Grasshopper sparrows compared to random grassland areas (open access)

Analysis of the habitat of Henslow's sparrows and Grasshopper sparrows compared to random grassland areas

Henslow's Sparrows are endangered prairie birds, and Grasshopper Sparrows are considered rare prairie birds. Both of these birds were abundant in Illinois, but their populations have been declining due to loss of the grasslands. This begins an ongoing study of the birds habitat so Fermilab can develop a land management plan for the Henslow's and Grasshoppers. The Henslow's were found at ten sites and Grasshoppers at eight sites. Once the birds were located, the vegetation at their sites was studied. Measurements of the maximum plant height, average plant height, and duff height were taken and estimates of the percent of grass, forbs, duff, and bare ground were recorded for each square meter studied. The same measurements were taken at ten random grassland sites on Fermilab property. Several t-tests were performed on the data, and it was found that both Henslow's Sparrows and Grasshopper Sparrows preferred areas with a larger percentage of grass than random areas. Henslow's also preferred areas with less bare ground than random areas, while Grasshoppers preferred areas with more bare ground than random areas. In addition, Grasshopper Sparrows preferred a lower percentage of forbs than was found in random areas and a shorter average plant height than …
Date: January 1, 2005
Creator: Maier, Kristen; Walton, Rod & Kasper, Peter
System: The UNT Digital Library
Inclusive and dijet b productions at CDF (open access)

Inclusive and dijet b productions at CDF

This contribution reports recent CDF measurements of the inclusive b-jet and b{bar b} dijet production cross sections obtained at the Tevatron Run II in p{bar p} collisions at {radical}s = 1.96 TeV. Preliminary results are in reasonable agreement with QCD predictions.
Date: January 1, 2005
Creator: Lefevre, R.
System: The UNT Digital Library
Tube-wave Effects in Cross-Well Seismic Data at StrattonField (open access)

Tube-wave Effects in Cross-Well Seismic Data at StrattonField

None
Date: January 1, 2005
Creator: Korneev, Valeri; Parra, Jorge & Bakulin, Andrey
System: The UNT Digital Library
High-resolution NMR spectroscopy of biological tissues using projected Magic Angle Spinning (open access)

High-resolution NMR spectroscopy of biological tissues using projected Magic Angle Spinning

High-resolution NMR spectra of materials subject toanisotropic broadening are usually obtained by rotating the sample aboutthe magic angle, which is 54.7 degrees to the static magnetic field. Inprojected Magic Angle Spinning (p-MAS), the sample is spun about twoangles, neither of which is the magic angle. This provides a method ofobtaining isotropic spectra while spinning at shallow angles. The p-MASexperiment may be used in situations where spinning the sample at themagic angle is not possible due to geometric or other constraints,allowing the choice of spinning angle to be determined by factors such asthe shape of the sample, rather than by the spin physics. The applicationof this technique to bovine tissue samples is demonstrated as a proof ofprinciple for future biological or medical applications.
Date: January 27, 2005
Creator: Martin, Rachel W.; Jachmann, Rebecca C.; Sakellariou, Dimitris; Nielsen, Ulla Gro & Pines, Alexander
System: The UNT Digital Library
The next generation of oxy-fuel boiler systems (open access)

The next generation of oxy-fuel boiler systems

Research in the area of oxy-fuel combustion which is being pioneered by Jupiter Oxygen Corporation combined with boiler research conducted by the USDOE/Albany Research Center has been applied to designing the next generation of oxy-fuel combustion systems. The new systems will enhance control of boiler systems during turn-down and improve response time while improving boiler efficiency. These next generation boiler systems produce a combustion product that has been shown to be well suited for integrated pollutant removal. These systems have the promise of reducing boiler foot-print and boiler construction costs. The modularity of the system opens the possibility of using this design for replacement of boilers for retrofit on existing systems.
Date: January 1, 2005
Creator: Ochs, Thomas L.; Gross, Alex (Jupiter Oxygen Corp.); Patrick, Brian (Jupiter Oxygen Corp.); Oryshchyn, Danylo B.; Summers, Cathy A. & Turner, Paul C.
System: The UNT Digital Library
Engineered refractoriers for slagging coal gasifiers (open access)

Engineered refractoriers for slagging coal gasifiers

The widespread commercial adaptation of slagging gasifier technology to produce power, fuel, and/or chemicals from coal will depend in large measure on the technology's ability to prove itself both economic and reliable. Improvements in gasifier reliability, availability, and maintainability will in part depend on the development of improved structural materials with longer service life in this application. Current generation refractory materials used to line the gasifier vessel, and contain the gasification reaction, often last no more than three to 18 months in commercial applications. The downtime required for tear-out and replacement of these critical materials results in gasifier on-line availabilities that fall short of targeted goals. In this talk we will discuss the development of improved refractory materials engineered specifically for longer service life in this application, with emphasis on the design of new refractories that contain little or no chrome.
Date: January 1, 2005
Creator: Bennett, James P.; Kwong, Kyei-Sing; Powell, Cynthia A; Krabbe, Rick & Thomas, Hugh
System: The UNT Digital Library
Status and performance of the CDF Run II silicon detector (open access)

Status and performance of the CDF Run II silicon detector

The CDF Run II silicon detector with its 8 layers of double- and single-sided silicon microstrip sensors and a total 722,432 readout channels is one of the largest silicon detector devices currently in use by a HEP experiment. We report our experience commissioning and operating this complex device during the first 4 years of Run II. As the luminosity delivered by the Tevatron increases, we have observed measurable effects of radiation damage in studies of charge collection and noise versus applied bias voltage at many different integrated luminosities. We discuss these studies and their impact on the expected lifetime of the detector.
Date: January 1, 2005
Creator: Boveia, A.
System: The UNT Digital Library
Standard Model Higgs searches at the Tevatron (open access)

Standard Model Higgs searches at the Tevatron

None
Date: January 1, 2005
Creator: Varelas, Nikos
System: The UNT Digital Library
Development of improved performance refractory liner materials for slagging gasifiers (open access)

Development of improved performance refractory liner materials for slagging gasifiers

Refractory liners for slagging gasifiers used in power generation, chemical production, or as a possible future source of hydrogen for a hydrogen based economy, suffer from a short service life. These liner materials are made of high Cr2O3 and lower levels of Al2O3 and/or ZrO2. As a working face lining in the gasifier, refractories are exposed to molten slags at elevated temperature that originate from ash in the carbon feedstock, including coal and/or petroleum coke. The molten slag causes refractory failure by corrosion dissolution and by spalling. The Albany Research Center is working to improve the performance of Cr2O3 refractories and to develop refractories without Cr2O3 or with Cr2O3 content under 30 wt pct. Research on high Cr2O3 materials has resulted in an improved refractory with phosphate additions that is undergoing field testing. Results to date of field trials, along with research direction on refractories with no or low Cr2O3, will be discussed.
Date: January 1, 2005
Creator: Kwong, Kyei-Sing; Bennett, James P.; Powell, Cynthia; Thomas, Hugh & Krabbe, Rick
System: The UNT Digital Library
Relaxation of atomic polarization in para+n-coated alkali-metal vapor cells (open access)

Relaxation of atomic polarization in para+n-coated alkali-metal vapor cells

None
Date: January 12, 2005
Creator: Graf, Miriam T.; Kimball, Derek F.; Rochester, Simon M.; Kerner, Katherine; Wong, Clement; Budker, Dmitry et al.
System: The UNT Digital Library