ENHANCED CHEMICAL CLEANING: A NEW PROCESS FOR CHEMICALLY CLEANING SAVANNAH RIVER WASTE TANKS (open access)

ENHANCED CHEMICAL CLEANING: A NEW PROCESS FOR CHEMICALLY CLEANING SAVANNAH RIVER WASTE TANKS

The Savannah River Site (SRS) has 49 high level waste (HLW) tanks that must be emptied, cleaned, and closed as required by the Federal Facilities Agreement. The current method of chemical cleaning uses several hundred thousand gallons per tank of 8 weight percent (wt%) oxalic acid to partially dissolve and suspend residual waste and corrosion products such that the waste can be pumped out of the tank. This adds a significant quantity of sodium oxalate to the tanks and, if multiple tanks are cleaned, renders the waste incompatible with the downstream processing. Tank space is also insufficient to store this stream given the large number of tanks to be cleaned. Therefore, a search for a new cleaning process was initiated utilizing the TRIZ literature search approach, and Chemical Oxidation Reduction Decontamination--Ultraviolet (CORD-UV), a mature technology currently used for decontamination and cleaning of commercial nuclear reactor primary cooling water loops, was identified. CORD-UV utilizes oxalic acid for sludge dissolution, but then decomposes the oxalic acid to carbon dioxide and water by UV treatment outside the system being treated. This allows reprecipitation and subsequent deposition of the sludge into a selected container without adding significant volume to that container, and without adding …
Date: January 17, 2008
Creator: Ketusky, E; Neil Davis, N & Renee Spires, R
System: The UNT Digital Library
Numerical studies of fluid-rock interactions in EnhancedGeothermal Systems (EGS) with CO2 as working fluid (open access)

Numerical studies of fluid-rock interactions in EnhancedGeothermal Systems (EGS) with CO2 as working fluid

There is growing interest in the novel concept of operating Enhanced Geothermal Systems (EGS) with CO{sub 2} instead of water as heat transmission fluid. Initial studies have suggested that CO{sub 2} will achieve larger rates of heat extraction, and can offer geologic storage of carbon as an ancillary benefit. Fluid-rock interactions in EGS operated with CO{sub 2} are expected to be vastly different in zones with an aqueous phase present, as compared to the central reservoir zone with anhydrous supercritical CO{sub 2}. Our numerical simulations of chemically reactive transport show a combination of mineral dissolution and precipitation effects in the peripheral zone of the systems. These could impact reservoir growth and longevity, with important ramifications for sustaining energy recovery, for estimating CO{sub 2} loss rates, and for figuring tradeoffs between power generation and geologic storage of CO{sub 2}.
Date: January 17, 2008
Creator: Xu, Tianfu; Pruess, Karsten & Apps, John
System: The UNT Digital Library
Efficient computation of matched solutions of the KV envelope equations for periodic focusing lattices. (open access)

Efficient computation of matched solutions of the KV envelope equations for periodic focusing lattices.

A new iterative method is developed to numerically calculate the periodic, matched beam envelope solution of the coupled Kapchinskij-Vladimirskij (KV) equations describing the transverse evolution of a beam in a periodic, linear focusing lattice of arbitrary complexity. Implementation of the method is straightforward. It is highly convergent and can be applied to all usual parameterizations of the matched envelope solutions. The method is applicable to all classes of linear focusing lattices without skew couplings, and also applies to parameters where the matched beam envelope is strongly unstable. Example applications are presented for periodic solenoidal and quadrupole focusing lattices. Convergence properties are summarized over a wide range of system parameters.
Date: January 17, 2006
Creator: Lund, S M; Chilton, S H & Lee, E P
System: The UNT Digital Library
Metrologies for the Phase Characterization of Attosecond (open access)

Metrologies for the Phase Characterization of Attosecond

EUV optics play a key role in attosecond science since only with higher photon energies is it possible to achieve the wide spectral bandwidth required for ultrashort pulses. Multilayer EUV mirrors have been proposed and are being developed to temporally shape (compress) attosecond pulses. To fully characterize a multilayer optic for pulse applications requires not only knowledge of the reflectivity, as a function of photon energy, but also the reflected phase of the mirror. This work develops the metrologies to determine the reflected phase of an EUV multilayer mirror using the photoelectric effect. The proposed method allows one to determine the optic's impulse response and hence its pulse characteristics.
Date: January 17, 2008
Creator: CXRO
System: The UNT Digital Library
Heavy Quarkonium Production in Single Transverse Polarized HighEnergy Scattering (open access)

Heavy Quarkonium Production in Single Transverse Polarized HighEnergy Scattering

We formulate the single transverse spin asymmetry in heavyquarkoniumproduction in lepton-nucleon and nucleon-nucleon collisionsinthe non-relativistic limit. We findthat the asymmetry is very sensitiveto the production mechanism. The finalstate interactions with the heavyquark and antiquark cancel out among themselves whenthe pair are producedin a color-single configuration, or cancel out with the initialstateinteraction in pp scattering when they are in color-octet. As aconsequence, the asymmetry is nonzero in ep collisions only in thecolor-octet model, whereas in pp collisions only in the color-singletmodel.
Date: January 17, 2008
Creator: Yuan, Feng
System: The UNT Digital Library
Exaggerated Health Benefits of Physical Fitness and Activity dueto Self-selection. (open access)

Exaggerated Health Benefits of Physical Fitness and Activity dueto Self-selection.

Background: The predicted health benefits of becomingphysically active or fit will be exaggerated if health outcomes causefitness and activity rather than the converse in prospective andcross-sectional epidemiological studies. Objective: Assess whether therelationships of adiposity to fitness and activity are explained byadiposity prior to exercising. Design: Cross-sectional study of physicalfitness (running speed during 10km foot race) and physical activity(weekly running distance) to current BMI (BMIcurrent) and BMI at thestart of running (BMIstarting) in 44,370 male and 25,252 femaleparticipants of the National Runners' Health Study. Results: BMIstartingexplained all of the association between fitness and BMIcurrent in bothsexes, but less than a third of the association between physical activityand BMIcurrent in men. In women, BMIstarting accounted for 58 percent ofthe association between BMIcurrent and activity levels. The 95thpercentile of BMIcurrent showed substantially greater declines withfitness and activity levels than the 5th percentile of BMIcurrent in men(i.e., the negative slope for 95th percentile was 2.6-fold greater thanthe 5th percentile for fitness and 3-fold greater for activity) and women(6-fold and 3.4-fold greater, respectively). At all percentiles, theregression slopes relating BMIstarting to fitness were comparable orgreater (more negative) than the slopes relating BMIcurrent to fitness,whereas the converse was true for activity. Conclusion: Self-selectionbias accounts for all …
Date: January 17, 2006
Creator: Williams, Paul T.
System: The UNT Digital Library
Collins Asymmetry at Hadron Colliders (open access)

Collins Asymmetry at Hadron Colliders

We study the Collins effect in the azimuthal asymmetricdistribution of hadrons inside a high energy jet in the single transversepolarized proton proton scattering. From the detailed analysis ofone-gluon and two-gluon exchange diagrams contributions, the Collinsfunction is found the same as that in the semi-inclusive deep inelasticscattering and e+e- annihilations. The eikonal propagators in thesediagrams do not contribute to the phase needed for the Collins-typesingle spin asymmetry, and the universality is derived as a result of theWard identity. We argue that this conclusion depends on the momentum flowof the exchanged gluon and the kinematic constraints in the fragmentationprocess, and is generic and model-independent.
Date: January 17, 2008
Creator: Yuan, Feng
System: The UNT Digital Library
Dihadron Tomography of High-Energy Nuclear Collisions inNext-to-Leading Order Perturbative QCD (open access)

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

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
System: The UNT Digital Library
Properties of Ellipticity Correlation with Atmospheric Structure From Gemini South (open access)

Properties of Ellipticity Correlation with Atmospheric Structure From Gemini South

Cosmic shear holds great promise for a precision independent measurement of {Omega}{sub m}, the mass density of the universe relative to the critical density. The signal is expected to be weak, so a thorough understanding of systematic effects is crucial. An important systematic effect is the atmosphere: shear power introduced by the atmosphere is larger than the expected signal. Algorithms exist to extract the cosmic shear from the atmospheric component, though a measure of their success applied to a range of seeing conditions is lacking. To gain insight into atmospheric shear, Gemini South imaging in conjunction with ground condition and satellite wind data were obtained. We find that under good seeing conditions Point-Spread-Function (PSF) correlations persist well beyond the separation typical of high-latitude stars. Under these conditions, ellipticity residuals based on a simple PSF interpolation can be reduced to within a factor of a few of the shot-noise induced ellipticity floor. We also find that the ellipticity residuals are highly correlated with wind direction. Finally, we correct stellar shapes using a more sophisticated procedure and generate shear statistics from stars. Under all seeing conditions in our data set the residual correlations lie everywhere below the target signal level. For good …
Date: January 17, 2007
Creator: Asztalos, Stephen J.; de Vries, W. H.; Rosenberg, L. J.; Treadway, T.; Burke, D.; Claver, C. et al.
System: The UNT Digital Library
Development of a Waste Treatment Process to Deactivate Reactive Uranium Metal and Produce a Stable Waste Form (open access)

Development of a Waste Treatment Process to Deactivate Reactive Uranium Metal and Produce a Stable Waste Form

This paper highlights the results of initial investigations conducted to support the development of an integrated treatment process to convert pyrophoric metallic uranium wastes to a non-pyrophoric waste that is acceptable for land disposal. Several dissolution systems were evaluated to determine their suitability to dissolve uranium metal and that yield a final waste form containing uranium specie(s) amenable to precipitation, stabilization, adsorption, or ion exchange. During initial studies, one gram aliquots of uranium metal or the uranium alloy U-2%Mo were treated with 5 to 60 mL of selected reagents. Treatment systems screened included acids, acid mixtures, and bases with and without addition of oxidants. Reagents used included hydrochloric, sulfuric, nitric, and phosphoric acids, sodium hypochlorite, sodium hydroxide and hydrogen peroxide. Complete dissolution of the uranium turnings was achieved with the H{sub 3}PO{sub 4}/HCI system at room temperature within minutes. The sodium hydroxide/hydrogen peroxide, and sodium hypochlorite systems achieved complete dissolution but required elevated temperatures and longer reaction times. A ranking system based on criteria, such as corrosiveness, temperature, dissolution time, off-gas type and amount, and liquid to solid ratio, was designed to determine the treatment systems that should be developed further for a full-scale process. The highest-ranking systems, nitric acid/sulfuric …
Date: January 17, 2002
Creator: Gates-Anderson, D D; Laue, C A & Fitch, T E
System: The UNT Digital Library
Decommissioning the Physics Laboratory, Building 777-10a, at the Savannah River Site (Srs) (open access)

Decommissioning the Physics Laboratory, Building 777-10a, at the Savannah River Site (Srs)

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.
System: The UNT Digital Library
Transversity GPD in photo- and electroproduction of two vectormesons (open access)

Transversity GPD in photo- and electroproduction of two vectormesons

The chiral-odd generalized parton distribution (GPD), or transversity GPD, of the nucleon can be accessed experimentally through the photo- or electroproduction of two vector mesons on a polarized nucleon target, {gamma}{sup (*)}N {yields} {rho}{sub 1}{rho}{sub 2}N', where {rho}{sub 1} is produced at large transverse momentum, {rho}{sub 2} is transversely polarized, and the mesons are separated by a large rapidity gap. We predict the cross section for this process for both transverse and longitudinal {rho}{sub 2} production. To this end we propose a model for the transversity GPDH{sub T}(x,{zeta},t), and give an estimate of the relative sizes of the transverse and longitudinal {rho}{sub 2}cross sections. We show that a dedicated experiment at high energy should be able to measure the transversity content of the proton.
Date: January 17, 2006
Creator: Enberg, Rikard; Pire, Bernard & Szymanowski, Lech
System: The UNT Digital Library
MODELING ATMOSPHERIC RELEASES OF TRITIUM FROM NUCLEAR INSTALLATIONS (open access)

MODELING ATMOSPHERIC RELEASES OF TRITIUM FROM NUCLEAR INSTALLATIONS

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 …
Date: January 17, 2007
Creator: Okula, K
System: The UNT Digital Library
Virialization Heating in Galaxy Formation (open access)

Virialization Heating in Galaxy Formation

In a hierarchical picture of galaxy formation virialization continually transforms gravitational potential energy into kinetic energies in the baryonic and dark matter. For the gaseous component the kinetic, turbulent energy is transformed eventually into internal thermal energy through shocks and viscous dissipation. Traditionally this virialization and shock heating has been assumed to occur instantaneously allowing an estimate of the gas temperature to be derived from the virial temperature defined from the embedding dark matter halo velocity dispersion. As the mass grows the virial temperature of a halo grows. Mass accretion hence can be translated into a heating term. We derive this heating rate from the extended Press Schechter formalism and demonstrate its usefulness in semi-analytical models of galaxy formation. Our method is preferable to the traditional approaches in which heating from mass accretion is only modeled implicitly through an instantaneous change in virial temperature. Our formalism can trivially be applied in all current semi-analytical models as the heating term can be computed directly from the underlying merger trees. Our analytic results for the first cooling halos and the transition from cold to hot accretion are in agreement with numerical simulations.
Date: January 17, 2007
Creator: Wang, P. (KIPAC, Menlo Park) & Abel, T. (Santa Barbara, KITP)
System: The UNT Digital Library
Demolitions of the Savannah River Site's Concentrator and Finishing Facilities (open access)

Demolitions of the Savannah River Site's Concentrator and Finishing Facilities

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.
System: The UNT Digital Library
Measurement of alpha / phi_2 from B to pi pi Decays (open access)

Measurement of alpha / phi_2 from B to pi pi Decays

The current results on B {yields} {pi}{pi} decays and SU(2) constraints on the Unitarity Triangle angle {alpha} or {phi}{sub 2} from the B-factories are summarized. Based on these measurements, predictions of the isospin analysis constraints at the end of the lifetime of both B-factories are given.
Date: January 17, 2007
Creator: Bevan, A.J.
System: The UNT Digital Library
Collaborations in Nuclear Reactors (open access)

Collaborations in Nuclear Reactors

None
Date: January 17, 2007
Creator: Bringa, E.; Caro, A.; Barton, N.; Marian, J.; Bulatov, V. & Arsenlis, T.
System: The UNT Digital Library
Reissner-Nordstrom Expansion (open access)

Reissner-Nordstrom Expansion

None
Date: January 17, 2006
Creator: Prodanov, E M; Ivanov, R I & Gueorguiev, V G
System: The UNT Digital Library
Models for Gamma-Ray Bursts and Diverse Transients (open access)

Models for Gamma-Ray Bursts and Diverse Transients

The observational diversity of ''gamma-ray bursts'' (GRBs) has been increasing, and the natural inclination is a proliferation of models. We explore the possibility that at least part of this diversity is a consequence of a single basic model for the central engine operating in a massive star of variable mass, differential rotation rate, and mass loss rate. Whatever that central engine may be--and here the collapsar is used as a reference point--it must be capable of generating both a narrowly collimated, highly relativistic jet to make the GRB, and a wide angle, sub-relativistic outflow responsible for exploding the star and making the supernova bright. To some extent, the two components may vary independently, so it is possible to produce a variety of jet energies and supernova luminosities. We explore, in particular, the production of low energy bursts and find a lower limit, {approx} 10{sup 48} erg s{sup -1} to the power required for a jet to escape a massive star before that star either explodes or is accreted. Lower energy bursts and ''suffocated'' bursts may be particularly prevalent when the metallicity is high, i.e., in the modern universe at low redshift.
Date: January 17, 2007
Creator: Woosley, S.E.; /UC, Santa Cruz; Zhang, Weiqun & /KIPAC, Menlo Park
System: The UNT Digital Library
Beam Test of a Prototype Phoswich Detector Assembly forthe PoGOLite Astronomical Soft Gamma-ray Polarimeter (open access)

Beam Test of a Prototype Phoswich Detector Assembly forthe PoGOLite Astronomical Soft Gamma-ray Polarimeter

We report about the beam test on a prototype of the balloon-based astronomical soft gamma-ray polarimeter, PoGOLite (Polarized Gamma-ray Observer--Light Version) conducted at KEK Photon Factory, a synchrotron radiation facility in Japan. The synchrotron beam was set at 30, 50, and 70 keV and its polarization was monitored by a calibrated polarimeter. The goal of the experiment was to validate the flight design of the polarimeter. PoGOLite is designed to measure polarization by detecting a Compton scattering and the subsequent photo-absorption in an array of 217 well-type phoswich detector cells (PDCs). The test setup included a first flight model PDC and a front-end electronics to select and reconstruct valid Compton scattering events. The experiment has verified that the flight PDC can detect recoil electrons and select valid Compton scattering events down to 30 keV from background. The measure azimuthal modulations (34.4 %, 35.8 % and 37.2 % at 30, 50, and 70 keV, respectively) agreed within 10% (relative) with the predictions by Geant4 implemented with dependence on the initial and final photon polarizations.
Date: January 17, 2007
Creator: Kanai, Y.; Ueno, M.; Kataoka, J.; Arimoto, M.; Kawai, N.; Yamamoto, K. et al.
System: The UNT Digital Library
Comprehending Software Architecture using a Single-View Visualization (open access)

Comprehending Software Architecture using a Single-View Visualization

Software is among the most complex human artifacts, and visualization is widely acknowledged as important to understanding software. In this paper, we consider the problem of understanding a software system's architecture through visualization. Whereas traditional visualizations use multiple stakeholder-specific views to present different kinds of task-specific information, we propose an additional visualization technique that unifies the presentation of various kinds of architecture-level information, thereby allowing a variety of stakeholders to quickly see and communicate current development, quality, and costs of a software system. For future empirical evaluation of multi-aspect, single-view architectural visualizations, we have implemented our idea in an existing visualization tool, Vizz3D. Our implementation includes techniques, such as the use of a city metaphor, that reduce visual complexity in order to support single-view visualizations of large-scale programs.
Date: January 17, 2007
Creator: Panas, T; Epperly, T W; Quinlan, D J; Saebjoernsen, A & Vuduc, R W
System: The UNT Digital Library
R&D of Accelerator Structures at SLAC (open access)

R&D of Accelerator Structures at SLAC

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.
System: The UNT Digital Library
Crustal thinning between the Ethiopian and East African Plateaus from modeling Rayleigh wave dispersion (open access)

Crustal thinning between the Ethiopian and East African Plateaus from modeling Rayleigh wave dispersion

The East African and Ethiopian Plateaus have long been recognized to be part of a much larger topographic anomaly on the African Plate called the African Superswell. One of the few places within the African Superswell that exhibit elevations of less than 1 km is southeastern Sudan and northern Kenya, an area containing both Mesozoic and Cenozoic rift basins. Crustal structure and uppermost mantle velocities are investigated in this area by modeling Rayleigh wave dispersion. Modeling results indicate an average crustal thickness of 25 {+-} 5 km, some 10-15 km thinner than the crust beneath the adjacent East African and Ethiopian Plateaus. The low elevations can therefore be readily attributed to an isostatic response from crustal thinning. Low Sn velocities of 4.1-4.3 km/s also characterize this region.
Date: January 17, 2006
Creator: Benoit, M H; Nyblade, A A & Pasyanos, M E
System: The UNT Digital Library