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Striped Bass Spawning in Non-Estuarine Portions of the Savannah River

Description: Historically, the estuarine portions of the Savannah River have been considered to be the only portion of the river in which significant amounts of striped bass (Morone saxatilis) spawning normally occur. A reexamination of data from 1983 through 1985 shows a region between River Kilometers 144 and 253 where significant numbers of striped bass eggs and larvae occur with estimated total egg production near that currently produced in the estuarine reaches. It appears possible that there are two separate spawning populations of striped bass in the Savannah River.
Date: April 17, 2007
Creator: Martin, D. & Paller, M.
Partner: UNT Libraries Government Documents Department

Multilayers are enabling new science with x-ray free electron lasers

Description: Newly developed multilayer-based mirrors and optical elements enable the imaging of high-resolution structure and ultrafast dynamics of samples with the soft X-ray free electron laser, FLASH, at DESY in Hamburg. The FLASH free-electron laser (FEL) produces intense ultrashort soft X-ray pulses with more than 10{sup 8} times higher peak brightness as compared with the most advanced synchrotron radiation sources. This allows time-resolved X-ray imaging and holography of nanostructures with a temporal resolution approaching 10 fs, opening up new studies of laser-matter interactions and the dynamics of correlated systems. In addition, the ultrafast pulses can be used to obtain structural data before the onset of radiation damage. This vastly increases the dose that can be used to record images of biological samples and hence improving the resolution of images. The extreme power of the X-ray pulses poses a challenge, and new methods are required to harness them. The methods developed here will also pave the way to imaging at upcoming hard-X-ray FELs. With those sources, atomic-resolution imaging of single uncrystallized macromolecules may become possible. In the first demonstration of ultrafast X-ray imaging at FLASH, a micron-sized test object was illuminated by a single focused coherent FEL pulse (Fig. 1). The coherent diffraction pattern of the object was recorded in the far field on a CCD detector. This pattern was numerically transformed to a high-resolution image of the object, using an iterative phase retrieval technique. This image, formed without the use of a lens, has a resolution limited only by the wavelength and the angular extent of the CCD detector. The lensless nature of coherent diffractive imaging has the advantage that no optical element need be placed near the object, and it is not necessary to carefully position the object - focusing is performed numerically in the phase retrieval step. However, the ...
Date: July 17, 2007
Creator: Bajt, S & Chapman, H N
Partner: UNT Libraries Government Documents Department

Two-stage sintering inhibits abnormal grain growth during beta to alpha transformation in SiC

Description: Free sintering of SiC with Al, B, and C additions in two successive stages, first under nitrogen and then under argon, produced a near full-density ceramic with equiaxed grain structure. The beta to alpha transformation proceeded to completion; however, the grain shape remained equiaxed due to the action of nitrogen present during the first stage of sintering. It is found that the beta to alpha transformation is necessary but not sufficient for producing the microstructure of interlocking plates found in high-toughness SiC.
Date: September 17, 2007
Creator: Kueck, Aaron M. & De Jonghe, Lutgard C.
Partner: UNT Libraries Government Documents Department

Fragmentation Cross Sections of 290 and 400 MeV/nucleon 12C Beamson Elemental Targets

Description: Charge-changing and fragment production cross sections at 0circ have been obtained for interactions of 290 MeV/nucleon and 400MeV/nucleon carbon beams with C, CH2, Al, Cu, Sn, and Pb targets. Thesebeams are relevant to cancer therapy, space radiation, and the productionof radioactive beams. We compare to previously published results using Cand CH2 targets at similar beam energies. Due to ambiguities arising fromthe presence of multiple fragments on many events, previous publicationshave reported only cross sections for B and Be fragments. In this work wehave extracted cross sections for all fragment species, using dataobtained at three distinct values of angular acceptance, supplemented bydata taken with the detector stack placed off the beam axis. A simulationof the experiment with the PHITS Monte Carlo code shows fair agreementwith the data obtained with the large acceptance detectors, but agreementis poor at small acceptance. The measured cross sections are alsocompared to the predictions of the one-dimensional cross section modelsEPAX2 and NUCFRG2; the latter is presently used in NASA's space radiationtransport calculations. Though PHITS and NUCFRG2 reproduce thecharge-changing cross sections with reasonable accuracy, none of themodels is able to accurately predict the fragment cross sections for allfragment species and target materials.
Date: March 17, 2007
Creator: Zeitlin, C.; Guetersloh, S.; Heilbronn, L.; Miller, J.; Fukumura,A.; Iwata, Y. et al.
Partner: UNT Libraries Government Documents Department

R&D of Accelerator Structures at SLAC

Description: The research activities for accelerator structures at SLAC are reviewed including the achievement via the main linac design for the Next Linear Collider (NLC), the program adjustment after the decision of the International Linear Collider (ILC) to be based on superconducting technology, and the work progress for the ILC, photon science at SLAC and basic accelerator structure studies.
Date: January 17, 2007
Creator: Wang, J.W.
Partner: UNT Libraries Government Documents Department

Recent Measurements of |V(Ub)| And Gamma in BaBar

Description: We present recent results of the measurements, employed by the BaBar Collaboration, of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element V{sub ub} in absolute value |V{sub ub}|, and phase {gamma}.
Date: October 17, 2007
Creator: Rotondo, Marcello
Partner: UNT Libraries Government Documents Department

Identification of High Energy Gamma-Ray Sources And Source Populations in the Era of Deep All-Sky Coverage

Description: A large fraction of the anticipated source detections by the Gamma-ray Large Area Space Telescope (GLAST-LAT) will initially be unidentified. We argue that traditional approaches to identify individuals and/or populations of gamma ray sources will encounter procedural limitations. Those limitations are discussed on the background of source identifications from EGRET observations. Generally, our ability to classify (faint) source populations in the anticipated GLAST dataset with the required degree of statistical confidence will be hampered by sheer source wealth. A new paradigm for achieving the classification of gamma ray source populations is discussed.
Date: April 17, 2007
Creator: Reimer, Olaf & Torres, Diego F.
Partner: UNT Libraries Government Documents Department

Operation of a Free-Electron Laser from the Extreme Ultraviolet to the Water Window

Description: We report results on the performance of a free-electron laser operating at a wavelength of 13.7 nm where unprecedented peak and average powers for a coherent extreme-ultraviolet radiation source have been measured. In the saturation regime, the peak energy approached 170 {micro}J for individual pulses, and the average energy per pulse reached 70 {micro}J. The pulse duration was in the region of 10 fs, and peak powers of 10 GW were achieved. At a pulse repetition frequency of 700 pulses per second, the average extreme-ultraviolet power reached 20mW. The output beam also contained a significant contribution from odd harmonics of approximately 0.6% and 0.03% for the 3rd (4.6 nm) and the 5th (2.75 nm) harmonics, respectively. At 2.75 nm the 5th harmonic of the radiation reaches deep into the water window, a wavelength range that is crucially important for the investigation of biological samples.
Date: December 17, 2007
Creator: Ackermann, W.; Asova, G.; Ayvazyan, V.; Azima, A.; Baboi, N.; Bahr, J. et al.
Partner: UNT Libraries Government Documents Department

Charm Dalitz Analyses at BaBar

Description: Dalitz plot analyses of D{sup 0} events reconstructed for the hadronic decay D{sup 0} {yields} {bar K}{sup 0}K{sup +}K{sup -} and D{sup 0} {yields} {bar K}{sup 0}{pi}{sup +}{pi}{sup -} are presented here. The analyses are based on a data sample of 91.5 fb{sup -1}. All data have been collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage rings at SLAC running at center-of-mass energies on and 40 MeV below the {Upsilon}(4S) resonance.
Date: January 17, 2007
Creator: Pappagallo, Margo
Partner: UNT Libraries Government Documents Department

Dihadron Tomography of High-Energy Nuclear Collisions inNext-to-Leading Order Perturbative QCD

Description: Back-to-back dihadron spectra in high-energy heavy-ioncollisions are studied within the next-to-leading order (NLO)perturbative QCD parton model with jet quenching incorporated viamodified jet fragmentation functions due to radiative parton energy lossin dense medium. The experimentally observed appearance of back-to-backdihadron sat high p_T is found to originate mainly from jet pairsproduced close and tangential to the surface of the dense matter.However, a substantial fraction of observed high p_T dihadrons also comesfrom jets produced at the center of the medium after losing finite amountof energy. Consequently, the suppression factor of such high-p_T hadronpairs is foundto be more sensitive to the initial gluon density than thesingle hadron spectra that are dominated by surface emission. Asimultaneous chi2-fit to both the single and dihadron spectra can beachieved within an arrow range of the energy loss parametersepsilon_0=1.6-2.1 GeV/fm. Because of the flattening of the initial jetproduction spectra, high p_T dihadrons at the LHC energy are found to bemore robust as probes of the dense medium.
Date: January 17, 2007
Creator: Zhang, Hanzhong; Owens, Joseph F.; Wang, Enke & Wang, Xin-Nian
Partner: UNT Libraries Government Documents Department

Power System Extreme Event Detection: The VulnerabilityFrontier

Description: In this work we apply graph theoretic tools to provide aclose bound on a frontier relating the number of line outages in a gridto the power disrupted by the outages. This frontier describes theboundary of a space relating the possible severity of a disturbance interms of power disruption, from zero to some maximum on the boundary, tothe number line outages involved in the event. We present the usefulnessof this analysis with a complete analysis of a 30 bus system, and presentresults for larger systems.
Date: October 17, 2007
Creator: Lesieutre, Bernard C.; Pinar, Ali & Roy, Sandip
Partner: UNT Libraries Government Documents Department

QUANTITATIVE EVALUATION OF FIRE SEPARATION AND BARRIERS

Description: Fire barriers, and physical separation are key components in managing the fire risk in Nuclear Facilities. The expected performance of these features have often been predicted using rules-of-thumb or expert judgment. These approaches often lack the convincing technical bases that exist when addressing other Nuclear Facility accident events. This paper presents science-based approaches to demonstrate the effectiveness of fire separation methods.
Date: April 17, 2007
Creator: Coutts, D
Partner: UNT Libraries Government Documents Department

GEOTECHNICAL ENGINEERING AT THE SAVANNAH RIVER SITE AND BECHTEL

Description: The authors describe two aspects of geotechnical engineering; site characterization utilizing the CPT and recognition of aging as a factor affecting soil properties. These methods were pioneered by Professor Schmertmann and are practiced by the Bechtel Corporation in general and at the Savannah River Site in South Carolina, in particular. This paper describes a general subsurface exploration approach that we have developed over the years. It consists of ''phasing'' the investigation, employing the principles of the observational method suggested by Peck (1969) and others. In doing so, we have found that the recommendations proposed by Sowers in terms of borehole spacing and exploration cost, are reasonable for developing an investigation program, recognizing that through continuous review the final investigation program will evolve. At the SRS shallow subsurface soils are of Eocene and Miocene age. It was recognized that the age of these deposits would have a marked effect on their cyclic resistance. A field investigation and laboratory testing program was devised to measure and account for aging as it relates to the cyclic resistance of the site soils. Recently, a panel of experts (Youd et al., 2001) has made recommendations regarding the liquefaction assessment of soils. This paper will address some of those recommendations in the context of re-assessing the liquefaction resistance of the soils at the SRS. It will be shown that, indeed, aging plays a major role in the cyclic resistance of the soils at the SRS, and that aging should be accounted for in liquefaction potential assessments for soils older than Holocene age.
Date: July 17, 2007
Creator: Lewis, M; I. Arango, I & Michael Mchood, M
Partner: UNT Libraries Government Documents Department

GLASS FORMULATION DEVELOPMENT TO SUPPORT MELTER TESTING TO DEMONSTRATE ENHANCED HIGH LEVEL WASTE THROUGHPUT

Description: The U.S. Department of Energy (DOE) is currently processing high-level waste (HLW) through a Joule-heated melter (JHM) at the Savannah River Site (SRS) and plans to vitrify HLW and Low activity waste (LAW) at the Hanford Site. Over the past few years at the DWPF, work has concentrated on increasing waste throughput. These efforts are continuing with an emphasis on high alumina content feeds. High alumina feeds have presented specific challenges for the JHM technology regarding the ability to increase waste loading yet still maintain product quality and adequate throughput. Alternatively, vitrification technology innovations are also being investigated as a means to increase waste throughput. The Cold Crucible Induction Melter (CCIM) technology affords the opportunity for higher vitrification process temperatures as compared to the current reference JHM technology. Higher process temperatures may allow for higher waste loading and higher melt rate. Glass formulation testing to support melter demonstration testing was recently completed. This testing was specifically aimed at high alumina concentration wastes. Glass composition property models were utilized as a guide for formulation development. Both CCIM and JHM testing will be conducted so glass formulation testing was targeted at both technologies with a goal to significantly increase waste loading without compromising product quality.
Date: August 17, 2007
Creator: Marra, J; David Peeler, D; Tommy Edwards, T; Kevin Fox, K; Amanda Youchak, A & James Gillam, J
Partner: UNT Libraries Government Documents Department

DEACTIVATION AND DECOMMISSIONING PLANNING AND ANALYSIS WITH GEOGRAPHIC INFORMATION SYSTEMS

Description: From the mid-1950's through the 1980's, the U.S. Department of Energy's Savannah River Site produced nuclear materials for the weapons stockpile, for medical and industrial applications, and for space exploration. Although SRS has a continuing defense-related mission, the overall site mission is now oriented toward environmental restoration and management of legacy chemical and nuclear waste. With the change in mission, SRS no longer has a need for much of the infrastructure developed to support the weapons program. This excess infrastructure, which includes over 1000 facilities, will be decommissioned and demolished over the forthcoming years. Dispositioning facilities for decommissioning and deactivation requires significant resources to determine hazards, structure type, and a rough-order-of-magnitude estimate for the decommissioning and demolition cost. Geographic information systems (GIS) technology was used to help manage the process of dispositioning infrastructure and for reporting the future status of impacted facilities.
Date: September 17, 2007
Creator: Bollinger, J; William Austin, W & Larry Koffman, L
Partner: UNT Libraries Government Documents Department

DECOMMISSIONING THE PHYSICS LABORATORY, BUILDING 777-10A, AT THE SAVANNAH RIVER SITE (SRS)

Description: SRS recently completed a four-year mission to decommission {approx}250 excess facilities. As part of that effort, SRS decommissioned a 48,000 ft{sup 2} laboratory that housed four low-power test reactors, formerly used by SRS to determine reactor physics. This paper describes and reviews the decommissioning, with a focus on component segmentation and handling (i.e. hazardous material removal, demolition, and waste handling). The paper is intended to be a resource for engineers, planners, and project managers who face similar decommissioning challenges.
Date: January 17, 2007
Creator: Musall, J & Cathy Sizemore, C
Partner: UNT Libraries Government Documents Department

DEMOLITIONS OF THE SAVANNAH RIVER SITE'S CONCENTRATOR AND FINISHING FACILITIES

Description: The Savannah River Site (SRS) has produced Special Nuclear Materials (SNMs) starting in the early 1950's to the mid 1970's for the Atomic Energy Commission (AEC) and from the mid 1970's to the present for the Department of Energy (DOE). In that time, over 1,000 facilities have been built in the sixteen (16) operational areas of the eight hundred (800) square kilometer site. Over the years, many of the facilities have been dispositioned by the DOE as inactive. In FY-03, DOE identified two hundred and forty-seven (247) (inactive or soon to be inactive) facilities that required demolition. Demolition work was scheduled to start in FY-04 and be completed in the first quarter of FY-07. Two-hundred and thirty-nine (239) of these facilities have been demolished employing Routine demolition techniques. This presentation reviews and discusses two (2) of the eight (8) Non-Routine demolitions Facilities, 420-D ''The Concentrator Facility'', and 421-D ''The Finishing Facility''.
Date: January 17, 2007
Creator: Mcdonagh, P & Cathy Sizemore, C
Partner: UNT Libraries Government Documents Department

MODELING ATMOSPHERIC RELEASES OF TRITIUM FROM NUCLEAR INSTALLATIONS

Description: Tritium source term analysis and the subsequent dispersion and consequence analyses supporting the safety documentation of Department of Energy nuclear facilities are especially sensitive to the applied software analysis methodology, input data and user assumptions. Three sequential areas in tritium accident analysis are examined in this study to illustrate where the analyst should exercise caution. Included are: (1) the development of a tritium oxide source term; (2) use of a full tritium dispersion model based on site-specific information to determine an appropriate deposition scaling factor for use in more simplified, broader modeling, and (3) derivation of a special tritium compound (STC) dose conversion factor for consequence analysis, consistent with the nature of the originating source material. It is recommended that unless supporting, defensible evidence is available to the contrary, the tritium release analyses should assume tritium oxide as the species released (or chemically transformed under accident's environment). Important exceptions include STC situations and laboratory-scale releases of hydrogen gas. In the modeling of the environmental transport, a full phenomenology model suggests that a deposition velocity of 0.5 cm/s is an appropriate value for environmental features of the Savannah River Site. This value is bounding for certain situations but non-conservative compared to the full model in others. Care should be exercised in choosing other factors such as the exposure time and the resuspension factor.
Date: January 17, 2007
Creator: Okula, K
Partner: UNT Libraries Government Documents Department

MODELING VENTILATION SYSTEM RESPONSE TO FIRE

Description: Fires in facilities containing nuclear material have the potential to transport radioactive contamination throughout buildings and may lead to widespread downwind dispersal threatening both worker and public safety. Development and implementation of control strategies capable of providing adequate protection from fire requires realistic characterization of ventilation system response which, in turn, depends on an understanding of fire development timing and suppression system response. This paper discusses work in which published HEPA filter data was combined with CFAST fire modeling predictions to evaluate protective control strategies for a hypothetical DOE non-reactor nuclear facility. The purpose of this effort was to evaluate when safety significant active ventilation coupled with safety class passive ventilation might be a viable control strategy.
Date: April 17, 2007
Creator: Coutts, D
Partner: UNT Libraries Government Documents Department

PHYSICAL AND CHEMICAL MEASUREMENTS NEEDED TO SUPPORT DISPOSITION OFSAVANNAH RIVER SITE RADIOACTIVE HIGH LEVEL WASTE SLUDGE

Description: Radioactive high level waste (HLW) sludge generated as a result of decades of production and manufacturing of plutonium, tritium and other nuclear materials is being removed from storage tanks and processed into a glass waste-form for permanent disposition at the Federal Repository. Characterization of this HLW sludge is a prerequisite for effective planning and execution of sludge disposition activities. The radioactivity of HLW makes sampling and analysis of the sludge very challenging, as well as making opportunities to perform characterization rare. In order to maximize the benefit obtained from sampling and analysis, a recommended list of physical property and chemical measurements has been developed. This list includes distribution of solids (insoluble and soluble) and water; densities of insoluble solids, interstitial solution, and slurry rheology (yield stress and consistency); mineral forms of solids; and primary elemental and radioactive constituents. Sampling requirements (number, type, volume, etc.), sample preparation techniques, and analytical methods are discussed in the context of pros and cons relative to end use of the data. Generation of useful sample identification codes and entry of results into a centralized database are also discussed.
Date: May 17, 2007
Creator: Hamm, B
Partner: UNT Libraries Government Documents Department

UTILIZING STATISTICS TO DETERMINE HOW MUCH SAMPLING AND ANALYSISIS WARRANTED TO SUPPORT SAVANNAH RIVER SITEHIGH LEVEL WASTE SLUDGE BATCH PREPARATION

Description: Accelerated cleanup initiatives at the SRS include expediting radioactive sludge processing. Sludge is the highest risk component of waste since it contains the highest concentrations of long-lived radionuclides. The sludge is staged into ''batches'' that are then the feed material to the Defense Waste Processing Facility (DWPF) which vitrifies the waste into a safe form for permanent disposal. The preparation of each batch includes sampling and analysis of the slurried material. The results of the characterization are used as the bases for batch blending and processing decisions. Uncertainty is inherent in the information used for planning. There is uncertainty in the quantity of sludge contained in a tank, the waste composition, and the waste physical properties. The goal of this analysis is to develop the basis for the number of physical samples that should be taken from the slurried waste tank and the number of replicates of laboratory measurements that should be performed in order to achieve a specified uncertainty level. Recommendations for sampling and analysis strategies are made based on the results of the analysis.
Date: May 17, 2007
Creator: Hamm, B
Partner: UNT Libraries Government Documents Department

TRADITIONAL METALLURGY, NANOTECHNOLOGIES AND STRUCTURAL MATERIALS: A SORBY AWARD LECTURE

Description: Traditional metallurgical processes are among the many ''old fashion'' practices that use nanoparticles to control the behavior of materials. Many of these practices were developed long before microscopy could resolve nanoscale features, yet the practitioners learned to manipulate and control microstructural elements that they could neither see nor identify. Furthermore, these early practitioners used that control to modify microstructures and develop desired material properties. Centuries old colored glass, ancient high strength steels and medieval organ pipes derived many of their desirable features through control of nanoparticles in their microstructures. Henry Sorby was among the first to recognize that the properties of rocks, minerals, metals and organic materials were controlled by microstructure. However, Mr. Sorby was accused of the folly of trying to study mountains with a microscope. Although he could not resolve nanoscale microstructural features, Mr. Sorby's observations revolutionized the study of materials. The importance of nanoscale microstructural elements should be emphasized, however, because the present foundation for structural materials was built by manipulating those features. That foundation currently supports several multibillion dollar industries but is not generally considered when the nanomaterials revolution is discussed. This lecture demonstrates that using nanotechnologies to control the behavior of metallic materials is almost as old as the practice of metallurgy and that many of the emergent nanomaterials technologists are walking along pathways previously paved by traditional metallurgists.
Date: July 17, 2007
Creator: Louthan, M
Partner: UNT Libraries Government Documents Department