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Complexants fsro Actinide Element Coordination & Immobilization
The goal of this project is to develop inorganic metal oxide clusters known as polyoxoanions (POAs) as complexants for the immobilization of actinide (An) ions from high-level waste (HLW). A diverse array of rugged isopolyoxoanions, [MxOy]z- , and heteropolyoxoanions, [XaMbOc]d-, comprised of M = V, Nb, Mo, W and X = Si, P polyhedra are under investigation for their ability to incarcerate An ions. The research combines two objectives-An-POA coordination and An-POA containment. The first involves the synthesis, isolation, and characterization of POAs that can selectively bind An ions to form stable An-POA complexes in alkaline and acidic solutions. The second involves investigations of the thermochemistry of the An-POA complexes under vitrification conditions germane to the formation of proposed HLW forms, such as borosilicate glass. The approach is envisioned to provide two levels of An encapsulation for maximum stability and durability as well as the potential to incorporate higher levels of An ions (particularly Pu) in waste forms than now possible. Such versatility bodes well for prospective applications of POAs as An complexants in technology of significance to the environmental management of HLW.
Date:
June 1, 2000
Creator:
Antonio, Mark R. & Soderholm, L.
Object Type:
Report
System:
The UNT Digital Library
Maximal neutrino mixing from a minimal flavor symmetry
The authors study a number of models, based on a non-Abelian discrete group, that successfully reproduce the simple and predictive Yukawa textures usually associated with U(2) theories of flavor. These models allow for solutions to the solar and atmospheric neutrino problems that do not require altering successful predictions for the charged fermions or introducing sterile neutrinos. Although Yukawa matrices are hierarchical in the models they consider, the mixing between second- and third-generation neutrinos is naturally large. They first present a quantitative analysis of a minimal model proposed in earlier work, consisting of a global fit to fermion masses and mixing angles, including the most important renormalization group effects. They then propose two new variant models: The first reproduces all important features of the SU(5) x U(2) unified theory with neither SU(5) nor U(2). The second demonstrates that discrete subgroups of SU(2) can be used in constructing viable supersymmetric theories of flavor without scalar universality even though SU(2) by itself cannot.
Date:
February 1, 2000
Creator:
Aranda, A.; Carone, C.D. & Lebed, R.F.
Object Type:
Article
System:
The UNT Digital Library
IDENTIFICATION OF NONLINEARITIES IN AN 8-DOF SYSTEM THROUGH SPECTRAL FEEDBACK
The accurate detection and characterization of nonlinearities associated with damage in structural systems is an area of vibration analysis that is being widely researched. In this paper, nonlinear behavior is considered a potential indicator of damage. Most conventional damage detection methods, such as those based on resonant frequencies and mode shapes, do not accurately identify the location and extent of nonlinearities present in a given structural system. As an extension of previous work at LANL, an effort is made to validate a damage detection method proposed by Adams. This method states that the frequency response function (FRF) matrix obtained from a low-level vibration test approximates the underlying linear FRF matrix of the system. The nonlinear systems' responses to high level excitation are combined with the linear FRF in a classic feedback loop to obtain the contributions of nonlinear internal forces. The temporal and spatial characteristics of the nonlinearities present in a structural system are identified. An 8-DOF system is used as a test case to validate the aforementioned method. Results of the tests and important issues concerning the method are presented.
Date:
August 1, 2000
Creator:
Arcand, B. & Wait, J.
Object Type:
Article
System:
The UNT Digital Library
Strong Earthquake Motion Estimates for Three Sites on the U.C. Riverside Campus
The approach of the Campus Earthquake Program (CEP) is to combine the substantial expertise that exists within the UC system in geology, seismology, and geotechnical engineering, to estimate the earthquake strong motion exposure of UC facilities. These estimates draw upon recent advances in hazard assessment, seismic wave propagation modeling in rocks and soils, and dynamic soil testing. The UC campuses currently chosen for application of our integrated methodology are Riverside, San Diego, and Santa Barbara. The procedure starts with the identification of possible earthquake sources in the region and the determination of the most critical fault(s) related to earthquake exposure of the campus. Combined geological, geophysical, and geotechnical studies are then conducted to characterize each campus with specific focus on the location of particular target buildings of special interest to the campus administrators. We drill and geophysically log deep boreholes next to the target structure, to provide direct in-situ measurements of subsurface material properties, and to install uphole and downhole 3-component seismic sensors capable of recording both weak and strong motions. The boreholes provide access below the soil layers, to deeper materials that have relatively high seismic shear-wave velocities. Analyses of conjugate downhole and uphole records provide a basis for …
Date:
November 1, 2000
Creator:
Archuleta, R.; Elgamal, A.; Heuze, F.; Lai, T.; Lavalle, D.; Lawrence, B. et al.
Object Type:
Report
System:
The UNT Digital Library
Continuum-Based FEM Modeling of Ceramic Powder Compaction Using a Cap-Plasticity Constitutive Model
Software has been developed and extended to allow finite element (FE) modeling of ceramic powder compaction using a cap-plasticity constitutive model. The underlying, general-purpose FE software can be used to model even the most complex three-dimensional (3D) geometries envisioned. Additionally, specialized software has been developed within this framework to address a general subclass of axisymmetric compacts that are common in industry. The expertise required to build the input deck, run the FE code, and post-process the results for this subclass of compacts is embedded within the specialized software. The user simply responds to a series of prompts, evaluates the quality of the FE mesh that is generated, and analyzes the graphical results that are produced. The specialized software allows users with little or no FE expertise to benefit from the tremendous power and insight that FE analysis can bring to the design cycle. The more general underlying software provides complete flexibility to model more complicated geometries and processes of interest to ceramic component manufacturers but requires significantly more user interaction and expertise.
Date:
May 1, 2000
Creator:
Arguello, Jose G., Jr.; Fossum, Arlo F.; Zeuch, David H. & Ewsuk, Kevin G.
Object Type:
Article
System:
The UNT Digital Library
Evaluation of mixed MOX-LEU loading patterns for LWRs originating from inability to deliver MOX assemblies: GE BWR/6 reload core study
None
Date:
January 1, 2000
Creator:
Ariani, I. & Turinsky, P. J.
Object Type:
Report
System:
The UNT Digital Library
Electrons in High Magnetic Fields
None
Date:
February 1, 2000
Creator:
Arko, A. J. & Cort, B. S.
Object Type:
Report
System:
The UNT Digital Library
Moments of the proton F{sub 2} structure function at low Q{sup 2}
The authors review the status of inclusive electron-proton scattering F{sub 2} structure function data in both the nucleon resonance region and the deep inelastic region, at momentum transfers below 5 (GeV/c){sup 2}. From these data they construct moments of F{sub 2}, down to momentum transfers of Q{sup 2}{approx}0.1(GeV/c){sup 2}. The second moment is only slowly varying with Q{sup 2} down to Q{sup 2}{approx}1, which is a reflection of duality. Below Q{sup 2} of 1 (GeV/c){sup 2}, the Q{sup 2} dependence of the moments is predominantly governed by the elastic contribution, whereas the inelastic channels still seem governed by local duality.
Date:
May 1, 2000
Creator:
Armstrong, C. S.; Ent, R.; Keppel, C. E.; Liuti, S.; Niculescu, G. & Niculescu, I.
Object Type:
Article
System:
The UNT Digital Library
Parallel Processing of a Groundwater Contaminant Code
The U. S. Department of Energy’s Idaho National Engineering and Environmental Laboratory (INEEL) is conducting a field test of experimental enhanced bioremediation of trichoroethylene (TCE) contaminated groundwater. TCE is a chlorinated organic substance that was used as a solvent in the early years of the INEEL and disposed in some cases to the aquifer. There is an effort underway to enhance the natural bioremediation of TCE by adding a non-toxic substance that serves as a feed material for the bacteria that can biologically degrade the TCE.
Date:
May 1, 2000
Creator:
Arnett, Ronald Chester & Greenwade, Lance Eric
Object Type:
Article
System:
The UNT Digital Library
Processing High Level Waste: Spectroscopic Characterization of Redox Reactions in Supercritical Water
We are engaged in a collaborative research effort with Los Alamos staff scientists Steven Buelow and Jeanne Robinson, staff members in group CST-6. The work proposed by these LANL staff scientists is directed towards the destruction of complexants and oxidation of chromium and technetium by hydrothermal processing in near critical or supercritical aqueous solutions. Our own work has been focused on a careful kinetic study of oxidation reactions of hydrogen peroxide with chromium hydroxide. This reaction occurs readily at ambient temperatures.
Date:
June 1, 2000
Creator:
Arrington, Charles A., (Jr.)
Object Type:
Report
System:
The UNT Digital Library
Study of the Axial Anomaly using the {gamma}p {yields} {pi}{sup +}P{pi}{sup 0} n Reaction Near Threshold
This experiment was one of the first photoproduction experiments performed at Jefferson Lab using the CLAS and the Photon Tagger. The event reconstruction and the photon flux determination procedures have been developed and were proven to work well as we can see from the cross section measurement of the {gamma}p {yields} {pi}{sup +}n reaction. The preliminary results at CLAS for this reaction agree very well with previous world data. The analysis procedure has been developed to analyze the double-pion photoproduction. The differential cross sections for the {gamma}p {yields} P{pi}{sup +}{pi}{sup 0}n reaction have been measured with incident photon energies between 1 and 2 GeV. The Chew-Low extrapolation technique was used to extract the associated {gamma}{pi} {yields} {pi}{pi} cross sections from the differential cross sections. The extrapolation procedure of extracting the pole cross section has been explored. F{sup 3{pi}} was obtained from the {gamma}{pi} {yields} {pi}{pi} cross sections. The results show a momentum dependence of the F{sup 3{pi}} amplitude in which they agree with Holstein's calculation. These measurements test fundamental predictions of low energies QCD. Future work on this analysis will help reduce the uncertainty in F{sup 3{pi}}, and extend the measurements to the lower and higher s regions.
Date:
May 1, 2000
Creator:
Asavapibhop, Burin
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Agile dry etching of compound semiconductors for science-based manufacturing using in-situ process control
In-situ optical diagnostics and ion beam diagnostics for plasma-etch and reactive-ion-beam etch (RIBE) tools have been developed and implemented on etch tools in the Compound Semiconductor Research Laboratory (CSRL). The optical diagnostics provide real-time end-point detection during plasma etching of complex thin-film layered structures that require precision etching to stop on a particular layer in the structure. The Monoetch real-time display and analysis program developed with this LDRD displays raw and filtered reflectance signals that enable an etch system operator to stop an etch at the desired depth within the desired layer. The ion beam diagnostics developed with this LDRD will permit routine analysis of critical ion-beam profile characteristics that determine etch uniformity and reproducibility on the RIBE tool.
Date:
February 1, 2000
Creator:
Ashby, Carol I.; Vawter, Gregory A.; Breiland, William G.; Bruskas, Larry A.; Woodworth, Joseph R. & Hebner, Gregory A.
Object Type:
Report
System:
The UNT Digital Library
Determination of Cu Concentrations in CdTe/CdS Devices by High Mass Resolution Secondary Ion Mass Spectrometry
We have used secondary ion mass spectrometry (SIMS) to quantitatively determine the concentration of Cu in CdTe/CdS devices. Empirical standards were fabricated by ion implantation of Cu into single-crystal and polycrystalline CdTe and single-crystal CdS.
Date:
January 1, 2000
Creator:
Asher, S. E.; Reedy, R. C.; Dhere, R.; Gessert, t. A. & Young, M. R.
Object Type:
Article
System:
The UNT Digital Library
Development of Novel, Simple, Multianalyte Sensors for Remote Environmental Analysis
We will develop simple, inexpensive new chemical sensing materials which can be used as visual color test strips to sensitively and selectively report on the concentration and identity of environmental pollutants such as cations of Pb, U, Pu, Sr, Hg, Cs, Co as well as other species. We will develop inexpensive chemical test strips which can be immersed in water to determine these analytes in the field. We will also develop arrays of these chemical sensing materials which will be attached to fiber optic bundles to be used as rugged multichannel optrodes to simultaneously monitor numerous analytes remotely in hostile environments. These sensing materials are based on the intelligent polymerized crystalline colloidal array (PCCA) technology we recently developed. This sensing motif utilizes a mesoscopically periodic array of colloidal particles polymerized into an acrylamide hydrogel. This array Bragg diffracts light in the visible spectral region due to the periodic array of colloidal particles. This material also contains chelating agents for the analytes of interest. When an analyte binds, its charge is immobilized within the acrylamide hydrogel. The resulting Donnan potential causes an osmotic pressure which swells the array proportional to the concentration of analyte bound. The diffracted wavelength shifts and the …
Date:
June 1, 2000
Creator:
Asher, Sanford A.
Object Type:
Report
System:
The UNT Digital Library
Mercury Removal at Idaho National Engineering and Environmental Laboratory's New Waste Calcining Facility
Technologies were investigated to determine viable processes for removing mercury from the calciner (NWCF) offgas system at the Idaho National Engineering and Environmental Laboratory. Technologies for gas phase and aqueous phase treatment were evaluated. The technologies determined are intended to meet EPA Maximum Achievable Control Technology (MACT) requirements under the Clean Air Act and Resource Conservation and Recovery Act (RCRA). Currently, mercury accumulation in the calciner off-gas scrubbing system is transferred to the tank farm. These transfers lead to accumulation in the liquid heels of the tanks. The principal objective for aqueous phase mercury removal is heel mercury reduction. The system presents a challenge to traditional methods because of the presence of nitrogen oxides in the gas phase and high nitric acid in the aqueous scrubbing solution. Many old and new technologies were evaluated including sorbents and absorption in the gas phase and ion exchange, membranes/sorption, galvanic methods, and UV reduction in the aqueous phase. Process modifications and feed pre-treatment were also evaluated. Various properties of mercury and its compounds were summarized and speciation was predicted based on thermodynamics. Three systems (process modification, NOxidizer combustor, and electrochemical aqueous phase treatment) and additional technology testing were recommended.
Date:
March 1, 2000
Creator:
Ashworth, Samuel Clay; Wood, R. A.; Taylor, D. D. & Sieme, D. D.
Object Type:
Article
System:
The UNT Digital Library
Chemical Conversion of TNT: Production of 2,4,6-Trinitrobenzoic Acid
None
Date:
August 1, 2000
Creator:
Asrat'ev, A.A.; Marchukov, V.A.; Suschev, V.G.; Aleksandrov, A.V.; Semenov, V.V.; Buchanan, A.C. et al.
Object Type:
Report
System:
The UNT Digital Library
Monitoring Thermo-Oxidative Degradation in Elastomers by NMR Relaxation Measurments
None
Date:
November 1, 2000
Creator:
Assink, Roger A.; Lang, David Patrick; Celina, M.; Sanderson, Briana & Gillen, Kenneth T.
Object Type:
Article
System:
The UNT Digital Library
Atmospheric Radiation Measurement Program Facilities Newsletter, May 2000.
Monthly newsletter discussing news and activities related to the Atmospheric Radiation Measurement Program, articles about weather and atmospheric phenomena, and other related topics.
Date:
June 1, 2000
Creator:
Atmospheric Radiation Measurement Program (U.S.)
Object Type:
Journal/Magazine/Newsletter
System:
The UNT Digital Library
Atmospheric Radiation Measurement Program Facilities Newsletter, November 2000.
Monthly newsletter discussing news and activities related to the Atmospheric Radiation Measurement Program, articles about weather and atmospheric phenomena, and other related topics.
Date:
December 1, 2000
Creator:
Atmospheric Radiation Measurement Program (U.S.)
Object Type:
Journal/Magazine/Newsletter
System:
The UNT Digital Library
The Effect of Nodalization on the Accuracy of the Finite Difference Solution of the Transient Conduction Equation.
One of the important phenomena that thermal-hydraulic codes such as RELAP5 must accurately calculate is heat transfer between a fluid and solid. Currently all thermal-hydraulic safety codes use the finite-difference technique to solve the transient conduction equation. This paper will examine the effect of different nodalization strategies on the accuracy of the finite-difference solution of a transient conduction problem with one convective boundary condition and no internal heat generation. The paper concludes with recommendations for choosing an appropriate nodalization scheme for modeling conduction in a wall without internal heat generation.
Date:
July 1, 2000
Creator:
Aumiller, D. L.
Object Type:
Article
System:
The UNT Digital Library
A coupled RELAPS-3D/CFD methodology with a proof-of-principle calculation
The RELAP5-3D computer code was modified to make the explicit coupling capability in the code fully functional. As a test of the modified code, a coupled RELAP5/RELAP5 analysis of the Edwards-O'Brien blowdown problem was performed which showed no significant deviations from the standard RELAP5-3D predictions. In addition, a multiphase Computational Fluid Dynamics (CFD) code was modified to permit explicit coupling to RELAP5-3D. Several calculations were performed with this code. The first analysis used the experimental pressure history from a point just upstream of the break as a boundary condition. This analysis showed that a multiphase CFD code could calculate the thermodynamic and hydrodynamic conditions during a rapid blowdown transient. Finally, a coupled RELAP5/CFD analysis was performed. The results are presented in this paper.
Date:
January 1, 2000
Creator:
Aumiller, D. L.; Tomlinson, E. T. & Bauer, R. C.
Object Type:
Report
System:
The UNT Digital Library
A new assessment of RELAP5-3D using a General Electric level swell problem
The RELAP5-3D (version bt) computer program was used to assess a GE level swell experiment. The primary goal of the new assessment models was to faithfully represent the experimental facility and instrumentation. In developing the new models, a non-physical representation of the vessel heads in a previous assessment was found. This distortion resulted in predictions that closely matched the experimental data, but were in error. The new assessment also highlighted an instability in the calculation of interfacial drag. To explore this issue, analyses were performed using three different interfacial drag correlations appropriate for large diameter pipes and/or vessels. The results of this study show that the Kataoka-Ishii correlation, which is currently used in RELAP5-3D, compares most favorably with the experimental data. Additionally, a numerical instability was uncovered with the analysis performed using the Gardner correlation and was traced to the calculation of bubble diameter in the bubbly flow regime.
Date:
September 1, 2000
Creator:
Aumiller, D. L.; Tomlinson, E. T. & Clarke, W. G.
Object Type:
Article
System:
The UNT Digital Library
The Impact of a Variety of Reprocessing Options on the Purity, Waste Generation, and Personnel Exposure
None
Date:
September 1, 2000
Creator:
Averill, W. A.; Boerigter, S. T. & AL, ET
Object Type:
Article
System:
The UNT Digital Library
Failure analysis of beryllium tile assembles following high heat flux testing for the ITER program
The following document describes the processing, testing and post-test analysis of two Be-Cu assemblies that have successfully met the heat load requirements for the first wall and dome sections for the ITER (International Thermonuclear Experimental Reactor) fusion reactor. Several different joint assemblies were evaluated in support of a manufacturing technology investigation aimed at diffusion bonding or brazing a beryllium armor tile to a copper alloy heat sink for fusion reactor applications. Judicious selection of materials and coatings for these assemblies was essential to eliminate or minimize interactions with the highly reactive beryllium armor material. A thin titanium layer was used as a diffusion barrier to isolate the copper heat sink from the beryllium armor. To reduce residual stresses produced by differences in the expansion coefficients between the beryllium and copper, a compliant layer of aluminum or aluminum-beryllium (AlBeMet-150) was used. Aluminum was chosen because it does not chemically react with, and exhibits limited volubility in, beryllium. Two bonding processes were used to produce the assemblies. The primary process was a diffusion bonding technique. In this case, undesirable metallurgical reactions were minimized by keeping the materials in a solid state throughout the fabrication cycle. The other process employed an aluminum-silicon layer …
Date:
May 1, 2000
Creator:
B. C. Odegard, Jr.; Cadden, C. H. & Yang, N. Y. C.
Object Type:
Report
System:
The UNT Digital Library