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ACCELERATING CLOSURE AT DOE SITES WITH EM'S SCIENCE AND TECHNOLOGY PROGRAM (open access)

ACCELERATING CLOSURE AT DOE SITES WITH EM'S SCIENCE AND TECHNOLOGY PROGRAM

Technical support is important for all U.S. Department of Energy (DOE) facilities facing difficult technical issues, aggressive remediation schedules, and tight budgets. It is especially vital for closure sites, which typically are smaller and have fewer resources available to apply to remediation activities. In many cases, closure sites and other small sites no longer have staff with the expertise required to overcome technical barriers on their own. As closure deadlines approach, special technical expertise is needed to identify, evaluate, and implement new and innovative approaches that will result in significant cost and schedule improvement for the waste disposition pathway. Site ''problem holders'' must have access to world-class scientific and engineering expertise from DOE national laboratories and research facilities, private industry, and universities to address immediate critical problems. In order to have confidence in the feasibility and results of innovative approaches, site contractors need to have the benefit of the valuable experiences of technicians who have faced similar problems and found solutions. The DOE Environmental Management (EM) Science and Technology (S&T) program recognizes the need of the closure sites to solve problems aggressively and is highly responsive to this need. Technical support from the S&T program can take many forms, such …
Date: February 27, 2003
Creator: Walker, J. S.; Toussaint, Craig R., (info: Ph.D.) & Gardner, E. J.
System: The UNT Digital Library
The dynamics of diluted Ho spin ice Ho2-xYxTi2O7 studied byneutron spin echo spectroscopy (open access)

The dynamics of diluted Ho spin ice Ho2-xYxTi2O7 studied byneutron spin echo spectroscopy

We have studied the spin relaxation in diluted spin ice Ho{sub 2-x} Y{sub x} Ti{sub 2}O{sub 7} by means of neutron spin echo spectroscopy. Remarkably, the geometrical frustration is not relieved by doping with non-magnetic Y, and the dynamics of the freezing is unaltered in the spin echo time window up to x {approx_equal} 1.6. At higher doping with non-magnetic Y (x {ge} 1.6) a new relaxation process at relatively high temperature (up to at least T {approx_equal} 55 K) appears which is more than 10 times faster than the thermally activated main relaxation process. We find evidence that over the whole range of composition all Ho spins participate in the dynamics. These results are compared to a.c. susceptibility measurements of the diluted Ho and Dy spin ice systems. X-ray absorption fine structure (EXAFS) spectra and x-ray diffraction show that the samples are structurally well ordered.
Date: February 27, 2006
Creator: Ehlers, G.; Gardner, J. S.; Booth, C. H.; Daniel, M.; Kam, K. C.; Cheetham, A. K. et al.
System: The UNT Digital Library
Formation of hydrogen negative ions by surface and volume processes with application to negative ion sources (open access)

Formation of hydrogen negative ions by surface and volume processes with application to negative ion sources

During the last few decades interest in negative-hydrogen ion sources has been directed mainly toward synchrotron and other particle accelerator applications, with emphasis on high current densities delivered for short pulses. But within the last several years there has been an awareness in the magnetic fusion program of the future need for negative ions as a means for generating high energy neutral beams, beams with energies above a few hundred keV. Negative ions seem to be the only effective intermediary for efficiently producing such beams. Although methods for generating negative ion beams have relied upon synchrotron concepts, the requirements for fusion are very different: here one is interested in more moderate current densities, up to 100 m A cm/sup -2/, but with continuous operation. Proposed source modules would accelerate of the order of 10 A of beam current and deliver several megawatts of beam power. Both H/sup -/ and D/sup -/ beams are being considered for application in different reactor systems. The conceptualization of negative ion sources is now in a very volatile stage. But of the great variety of proposals that have been offered to date, three general areas appear ready for development. These are: first, the double charge …
Date: June 27, 1979
Creator: Hiskes, J.R.
System: The UNT Digital Library
Biosignatures of Pathogen and Host (open access)

Biosignatures of Pathogen and Host

In information theory, a signature is characterized by the information content as well as noise statistics of the communication channel. Biosignatures have analogous properties. A biosignature can be associated with a particular attribute of a pathogen or a host. However, the signature may be lost in backgrounds of similar or even identical signals from other sources. In this paper, we highlight statistical and signal processing challenges associated with identifying good biosignatures for pathogens in host and other environments. In some cases it may be possible to identify useful signatures of pathogens through indirect but amplified signals from the host. Discovery of these signatures requires new approaches to modeling and data interpretation. For environmental biosignal collections, it is possible to use signal processing techniques from other applications (e.g., synthetic aperture radar) to track the natural progression of microbes over large areas. We also present a computer-assisted approach to identify unique nucleic-acid based microbial signatures. Finally, an understanding of host-pathogen interactions will result in better detectors as well as opportunities in vaccines and therapeutics.
Date: August 27, 2002
Creator: Fitch, J. P.; Chromy, B. A.; Forde, C. E.; Garcia, E.; Gardner, S. N.; Gu, P. P. et al.
System: The UNT Digital Library
High Biomass Low Export Regimes in the Southern Ocean (open access)

High Biomass Low Export Regimes in the Southern Ocean

This paper investigates ballasting and remineralization controls of carbon sedimentation in the twilight zone (100-1000 m) of the Southern Ocean. Size-fractionated (<1 {micro}m, 1-51 {micro}m, >51 {micro}m) suspended particulate matter was collected by large volume in-situ filtration from the upper 1000 m in the Subantarctic (55 S, 172 W) and Antarctic (66 S, 172 W) zones of the Southern Ocean during the Southern Ocean Iron Experiment (SOFeX) in January-February 2002. Particles were analyzed for major chemical constituents (POC, P, biogenic Si, CaCO3), and digital and SEM image analyses of particles were used to aid in the interpretation of the chemical profiles. Twilight zone waters at 66 S in the Antarctic had a steeper decrease in POC with depth than at 55 S in the Subantarctic, with lower POC concentrations in all size fractions at 66 S than at 55 S, despite up to an order of magnitude higher POC in surface waters at 66 S. The decay length scale of >51 {micro}m POC was significantly shorter in the upper twilight zone at 66 S ({delta}{sub e}=26 m) compared to 55 S ({delta}{sub e}=81 m). Particles in the carbonate-producing 55 S did not have higher excess densities than particles from the …
Date: January 27, 2006
Creator: Lam, Phoebe J. & Bishop, James K.B.
System: The UNT Digital Library
Observation of snake resonances at Relativistic Heavy Ion Collider (open access)

Observation of snake resonances at Relativistic Heavy Ion Collider

The Siberian snakes are powerful tools in preserving polarization in high energy accelerators has been demonstrated at the Brookhaven Relativistic Heavy Ion Collider (RHIC). Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the Siberian snakes also introduce a new set of depolarization resonances, i.e. snake resonances as first discovered by Lee and Tepikian. The intrinsic spin resonances above 100 GeV are about a factor of two stronger than those below 100 GeV which raises the challenge to preserve the polarization up to 250 GeV. In 2009, polarized protons collided for the first time at the RHIC design store energy of 250 GeV. This paper presents the experimental measurements of snake resonances at RHIC. The plan for avoiding these resonances is also presented.
Date: September 27, 2010
Creator: Bai, M.; Ahrens, L.; Alekseev, I.G.; Alessi, J. & al, et
System: The UNT Digital Library
PRESERVATION OF H2 PRODUCTION ACTIVITY IN NANOPOROUS LATEX COATINGS OF RHODOPSEUDOMONAS PALUSTRIS CGA009 DURING DRY STORAGE AT AMBIENT TEMPERATURES (open access)

PRESERVATION OF H2 PRODUCTION ACTIVITY IN NANOPOROUS LATEX COATINGS OF RHODOPSEUDOMONAS PALUSTRIS CGA009 DURING DRY STORAGE AT AMBIENT TEMPERATURES

To assess the applicability of latex cell coatings as an "off-the-shelf' biocatalyst, the effect of osmoprotectants, temperature, humidity and O{sub 2} on preservation of H{sub 2} production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H{sub 2} production. Beyond 2 weeks of storage, sorbitol- treated coatings lost all H{sub 2} production activity, whereas considerable H{sub 2} production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H{sub 2} production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H{sub 2} (0-0.1% headspace accumulation), whereas those stored at <5% humidity retained 27-53% of their H{sub 2} production activity after 8 weeks of storage. When stored in argon at <5% humidity and room temperature, R. palustris coatings retained full H{sub 2} production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of …
Date: August 27, 2012
Creator: Milliken, C.; Piskorska, M.; Soule, T.; Gosse, J.; Flickinger, M.; Smith, G. et al.
System: The UNT Digital Library
Projection Gas Immersion Laser Doping (P-GILD): A resistless, nanosecond thermal doping/diffusion technology (open access)

Projection Gas Immersion Laser Doping (P-GILD): A resistless, nanosecond thermal doping/diffusion technology

Projection Gas Immersion Laser Doping (P-GILD) is an innovative doping process that utilizes finely patterned excimer laser light to thermally process discreet regions within an integrated circuit. By reducing the total temperature cycle to nanoseconds and localizing the thermal energy in depth and area, P-GILD fundamentally changes the junction formation process. This paper first reviews the general characteristics of the P-GILD process and equipment. Two variations of the technique, melt and non-melt, and their resulting junction characteristics are then described in detail. The combination of the two laser processes along with the simplification that a resistless technology brings to the process sequence, enables efficient fabrication of impurity profiles that are ideal for a wide array of transistor applications.
Date: July 27, 1994
Creator: Weiner, K. H.
System: The UNT Digital Library
Self-efficacy mechanism at work: The context of environmental volunteer travel (open access)

Self-efficacy mechanism at work: The context of environmental volunteer travel

This article contributes the first utilization of Bandura’s self-efficacy (SE) mechanism in the context of environmental volunteer travel demonstrating how environmental stewardship, hedonic experience, and environmental SE relate to one another in this particular setting
Date: December 27, 2018
Creator: Strzelecka, Marianna; Woosnam, Kyle M. & Nisbett, Gwendelyn S.
System: The UNT Digital Library
Molecular potentials and relaxation dynamics (open access)

Molecular potentials and relaxation dynamics

The use of empirical pseudopotentials, in evaluating interatomic potentials, provides an inexpensive and convenient method for obtaining highly accurate potential curves and permits the modeling of core-valence correlation, and the inclusion of relativistic effects when these are significant. As an example, recent calculations of the chi/sup 1/..sigma../sup +/ and a/sup 3/..sigma../sup +/ states of LiH, NaH, KH, RbH, and CsH and the chi/sup 2/..sigma../sup +/ states of their anions are discussed. Pseudopotentials, including core polarization terms, have been used to replace the core electrons, and this has been coupled with the development of compact, highly-optimized basis sets for the corresponding one- and two-electron atoms. Comparisons of the neutral potential curves with experiment and other ab initio calculations show good agreement (within 1000 cm/sup -1/ over most of the potential curves) with the difference curves being considerably more accurate.
Date: March 27, 1981
Creator: Karo, A.M.
System: The UNT Digital Library
Chemistry of Supraglacial Ponds in thte Debris-Covered Area of Lirung Glacier in Central Nepal Himalayas (open access)

Chemistry of Supraglacial Ponds in thte Debris-Covered Area of Lirung Glacier in Central Nepal Himalayas

This article examines elevation trends and their control by seasonality, dominant geochemical processes, and season dynamics in these supraglacial ponds at elevations ranging between 3989 and 4292 m above sea level in the debris-covered area of Lirung glacier in central Nepal Himalayas, from November 2010 to October 2011 on a bimonthly basis.
Date: August 27, 2015
Creator: Bhatt, Maya P.; Takeuchi, Nozomu & Acevedo, Miguel F.
System: The UNT Digital Library
Assessing the Security Vulnerabilities of Correctional Facilities (open access)

Assessing the Security Vulnerabilities of Correctional Facilities

The National Institute of Justice has tasked their Satellite Facility at Sandia National Laboratories and their Southeast Regional Technology Center in Charleston, South Carolina to devise new procedures and tools for helping correctional facilities to assess their security vulnerabilities. Thus, a team is visiting selected correctional facilities and performing vulnerability assessments. A vulnerability assessment helps to identi~ the easiest paths for inmate escape, for introduction of contraband such as drugs or weapons, for unexpected intrusion fi-om outside of the facility, and for the perpetration of violent acts on other inmates and correctional employees, In addition, the vulnerability assessment helps to quantify the security risks for the facility. From these initial assessments will come better procedures for performing vulnerability assessments in general at other correctional facilities, as well as the development of tools to assist with the performance of such vulnerability assessments.
Date: October 27, 1998
Creator: Morrison, G. Steve & Spencer, Debra S.
System: The UNT Digital Library
Synthesis and Reactivity of a Coordinatively Unsaturated Ruthenium(II) Parent Amido Complex: Studies of X-H Activation (X = H or C) (open access)

Synthesis and Reactivity of a Coordinatively Unsaturated Ruthenium(II) Parent Amido Complex: Studies of X-H Activation (X = H or C)

Article discussing the synthesis and reactivity of a coordinatively unsaturated Ruthenium(II) parent amido complex and studies of X-H activation (X = H or C).
Date: April 27, 2004
Creator: Conner, David; Jayaprakash, K. N.; Cundari, Thomas R., 1964- & Gunnoe, T. Brent
System: The UNT Digital Library