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A comparison of the PARET/ANL and RELAP5/MOD3 codes for the analysis of IAEA benchmark transients
The PARET/ANL and RELAP5/MOD3 codes are used to analyze the series of benchmark transients specified for the IAEA Research Reactor Core Conversion Guidebook (IAEA-TECDOC-643, Vol. 3). The computed results for these loss-of-flow and reactivity insertion transients with scram are in excellent agreement and agree well with the earlier results reported in the guidebook. Attempts to also compare RELAP5/MOD3 with the SPERT series of experiments are in progress.
Date:
December 31, 1996
Creator:
Woodruff, W.L.; Hanan, N.A.; Smith, R.S. & Matos, J.E.
Object Type:
Article
System:
The UNT Digital Library
Comparisons of TORT and MCNP dose calculations for BNCT treatment planning
The relative merit of using a deterministic code to calculate dose distributions for BNCT applications were examined. The TORT discrete deterministic ordinated code was used in comparison to MCNP4A to calculate dose distributions for BNCT applications
Date:
December 31, 1996
Creator:
Ingersol, D. T.; Slater, C. O.; Williams, L. R.; Redmond, E. L., II & Zamenhof, R. G.
Object Type:
Article
System:
The UNT Digital Library
Compendium of equations for the design of a very large hadron collider
In this report the author gives several relationships which are used for the preliminary design and to estimate the collider performance. He limits to the case of the performance during storage and colliding mode. These relationships are for: (1)Luminosity and beam-beam tune-shift; (2) microwave longitudinal instability; and (3) synchrotron radiation effects.
Date:
December 31, 1996
Creator:
Ruggiero, Alessandro G.
Object Type:
Article
System:
The UNT Digital Library
Competition between gettering by implantation-induced cavities in silicon and internal gettering associated with SiO{sub 2} precipitation
Dissolved or metallic impurities can degrade silicon integrated circuit (IC) device yields when present in the near surface, active device region. This is such a critical issue that the IC community has set specifications for the reduction of metallic impurities down to 2.5 {times} 10{sup 9} atoms/cm{sup 3}. The exceptionally high diffusivity and solubility of Cu and Fe in silicon and their presence in many processing tools makes these impurities of particular interest. Additionally, Cu is being considered as an interconnect material because of its low electrical resistivity which creates a high potential for contamination. Here, the gettering behavior of Cu and Fe was investigated in CZ silicon which contained both internal-gettering sites in the bulk due to SiO{sub 2} precipitation and a device-side layer of cavities formed by He implantation and annealing. The objective was to quantify the effectiveness of impurity gettering at cavities relative to the widely used internal-gettering process. Both rapid thermal anneals and furnace anneals were used during the gettering sequences to reveal transient effects as well as the final, thermodynamically-equilibrated condition. For temperatures of 700, 800 and 850 C, the cavity gettering was observed to predominate over internal gettering as indicated both by the number …
Date:
December 31, 1996
Creator:
McHugo, S. A.; Weber, E. R.; Myers, S. M. & Petersen, G. A.
Object Type:
Report
System:
The UNT Digital Library
Complete chemical analysis of aerosol particles in real-time
Real-time mass spectrometry of individual aerosol particles using an ion trap mass spectrometer is described. The microparticles are sampled directly from the air by a particle inlet system into the vacuum chamber. An incoming particle is detected as it passes through two CW laser beams and a pulsed laser is triggered to intercept the particle for laser ablation ionization at the center of the ion trap. The produced ions are analyzed by the ion trap mass spectrometer. Ions of interest are selected and dissociated through collision with buffer gas atoms for further fragmentation analysis. Real-time chemical analyses of inorganic, organic, and bacterial aerosol articles have been demonstrated. It has been confirmed that the velocity and the size of the incoming particles highly correlate to each other. The performance of the inlet system, particle detection, and preliminary results are discussed.
Date:
December 31, 1996
Creator:
Yang, Mo; Reilly, P. T. A.; Gieray, R. A.; Whitten, W. B. & Ramsey, J. M.
Object Type:
Article
System:
The UNT Digital Library
Composite fermions in 2 x 10{sup 6} cm{sup 2}/Vs mobility A1GaAs/GaAs heterostructures grown by MOCVD
Recent growth by MOCVD (metalorganic chemical vapor deposition) of 2.0x10{sup 6} cm{sup 2}/Vs mobility heterostructures are reported. These mobilities, the highest reported to date, are attributed to use of tertiarybutylarsine as the arsenic precursor. Measurements in tilted magnetic fields of the fractional quantum Hall effect states near filling factor 3/2 are consistent with a spin-split composite fermion (CF) model proposed earlier. Extracted values of the product of the CF g-factor and CF effective mass agree with values previously obtained for MBE samples.
Date:
December 31, 1996
Creator:
Simmons, J.A., Chui, H.C., Harff, N.E., Hammons, B.E. & Du, R.R., Zudov, M.A.
Object Type:
Article
System:
The UNT Digital Library
Composite particle production in relativistic Au+Au collisions at AGS: First results from the E866 forward spectrometer @ 2, 4, and 10.8 A{center_dot}GeV
Particle spectra were measured for Au + Au collisions at 2, 4, and 10. 8 A{center_dot}GeV using the E866 spectrometers. Recent results on proton emission and composite particle production form the E866 forward spectrometer data taken in 1994 together with the first results from the 1995/6 AGS running period are presented. Preliminary results indicate a decrease in the coalescence scaling coefficient with increasing projectile energy and centrality.
Date:
December 31, 1996
Creator:
Ashktorab, K.
Object Type:
Article
System:
The UNT Digital Library
Composition and function in AB{sub 5} hydride electrodes
Multicomponent AB, hydrides are attractive replacements for the cadmium electrode in nickel - cadmium batteries. This paper is concerned with the differential effects of Ni substitution by cobalt, Mn and Al upon electrode corrosion and capacity, using alloys having the generic composition of Al(NiCoMnAl){sub 5} and similar to those used for the preparation of commercial battery electrodes. The corrosion of metal hydride electrodes is determined by two factors, surface passivation due to the presence of surface oxides or hydroxides and crystal lattice expansion - contraction the charge - discharge process. Thus, in addition to determining the effects of Ni substitution we will also address the question of whether an observed change is due to a change lattice expansion or to a change in surface passivation, e.g. the formation a corrosion resistant oxide layer.
Date:
December 31, 1996
Creator:
Adzic, G. D.; Johnson, J. R.; Mukerjee, S.; McBreen, J. & Reilly, J. J.
Object Type:
Report
System:
The UNT Digital Library
Computation of porosity and water content from geophysical logs, Yucca Mountain, Nevada
Neutron and density logs acquired in boreholes at Yucca Mountain, Nevada are used to determine porosity and water content as a function of depth. Computation of porosity requires an estimate of grain density, which is provided by core data, mineralogical data, or is inferred from rock type where neither core nor mineralogy are available. The porosity estimate is merged with mineralogical data acquired by X-ray diffraction to compute the volumetric fractions of major mineral groups. The resulting depth-based portrayal of bulk rock composition is equivalent to a whole rock analysis of mineralogy and porosity. Water content is computed from epithermal and thermal neutron logs. In the unsaturated zone, the density log is required along with a neutron log. Water content can also be computed from dielectric logs, which were acquired in only a fraction of the boreholes, whereas neutron logs were acquired in all boreholes. Mineralogical data are used to compute a structural (or bound) water estimate, which is subtracted from the total water estimate from the neutron-density combination. Structural water can be subtracted only from intervals where mineralogical analyses are available; otherwise only total water can be reported. The algorithms and procedures are applied to logs acquired during 1979 …
Date:
December 31, 1996
Creator:
Nelson, P. H.
Object Type:
Report
System:
The UNT Digital Library
Computational modeling and experimental studies on NO{sub x} reduction under pulverized coal combustion conditions. Seventh quarterly technical progress report, July 1, 1996--September 30, 1996
During this quarter (July-August 1996), the experiments for nitric oxide reburning with a combination of methane and ammonia were conducted successfully. This marked the completion of gaseous phase experiments. Preparations are underway for the reburning studies with coal. A coal feeder was designed to suit our reactor facility which is being built by MK Fabrication. The coal feeder should be operational in the coming quarter. Presented here are the experimental results of NO reburning with methane/ammonia. The results are consistent with the computational work submitted in previous reports.
Date:
December 31, 1996
Creator:
Kumpaty, S. K.; Subramanian, K.; Nokku, V. P. & Hodges, T. L.
Object Type:
Report
System:
The UNT Digital Library
Computational modeling and experimental studies on NO{sub x} reduction under pulverized coal combustion conditions. Technical progress report, sixth quarter, April 1--June 30, 1996
During this quarter, the experiments for nitric oxide reburning with a combination of methane and acetylene were conducted successfully. With the failure of ozonator lamp in the NOx analyzer shortly thereafter, the experimental study of nitric oxide reburning with a combination of methane and ammonia could not be completed. In the meantime, a coal feeder was designed and a purchase order was sent out for the building of the coal feeder. Presented herein are the experimental results of NO reburning with methane/acetylene. The results are consistent with model predictions.
Date:
December 31, 1996
Creator:
Kumpaty, S. K.; Subramanian, K.; Nokku, V. P. & Hodges, T. L.
Object Type:
Report
System:
The UNT Digital Library
Computational modeling of magentically driven liner-on-plasma fusion experiments
Magnetized Target Fusion (MTF) is an approach to controlled fusion which potentially avoids the difficulties of the traditional magnetic and inertial confinement approaches. It appears possible to investigate the critical issues for MTF at low cost, relative to traditional fusion programs, utilizing pulsed power drivers much less expensive than ICF drivers, and plasma configurations much less expensive than those needed for full magnetic confinement. Computational and experimental research into MTF is proceeding at Los Alamos, VNIIEF, and other laboratories.
Date:
December 31, 1996
Creator:
Sheehey, Peter T.; Faehl, Rickey J.; Kirkpatrick, Ronald C. & Lindemuth, Irvin R.
Object Type:
Article
System:
The UNT Digital Library
Computing the apparent centroid of radar targets
A high-frequency multibounce radar scattering code was used as a simulation platform for demonstrating an algorithm to compute the ARC of specific radar targets. To illustrate this simulation process, several targets models were used. Simulation results for a sphere model were used to determine the errors of approximation associated with the simulation; verifying the process. The severity of glint induced tracking errors was also illustrated using a model of an F-15 aircraft. It was shown, in a deterministic manner, that the ARC of a target can fall well outside its physical extent. Finally, the apparent radar centroid simulation based on a ray casting procedure is well suited for use on most massively parallel computing platforms and could lead to the development of a near real-time radar tracking simulation for applications such as endgame fuzing, survivability, and vulnerability analyses using specific radar targets and fuze algorithms.
Date:
December 31, 1996
Creator:
Lee, C.E.
Object Type:
Article
System:
The UNT Digital Library
Conceptual Design for High Mass Imploding Liner Experiments
We have summarized some of the motivation behind high energy liner experiments. We have identified the 100-cm-diameter Disk Explosive-Magnetic Gene promising candidate for powering such experiments and described a phenomenological modeling approach used to understand the limits of DEMG operation. We have explored the liner implosion parameter space that can be addressed by such systems and have selected a design point from which to develop a conceptual experiment. We have applied the phenomenological model to the point design parameters and used 1 D MHD tools to assess the behavior of the liner for parameters at the design point. We have not to optimized the choice of pulse power or liner parameters. We conclude that operating in the velocity range of 10-20 km/s, kinetic energies around 100 MJ are practical with currents approaching 200 MA in the liner. Higher velocities (up to almost 40 km/s) are achieved on the inner surface of a thick liner when the liner collapses to I -cm radius. At 6-cm radius the non- optimized liners explored here are attractive drivers for experiments exploring the compression of magnetized plasmas and at 1 cm they are equally attractive drivers for shock wave experiments in the pressure range of …
Date:
December 31, 1996
Creator:
Reinovsky, R. E.; Clark, D. A. & Ekdahl, C. A.
Object Type:
Article
System:
The UNT Digital Library
A conceptual performance assessment model of the dissolved actinide source term for the WIPP
This paper presents a performance assessment model of dissolved actinide concentrations for the Waste Isolation Pilot Plant (WIPP). The model assesses the concentration of each actinide oxidation state and combines these concentrations with an oxidation state distribution. The chemical behavior of actinides in the same oxidation state is presumed to be very similar for almost all situations, but exceptions arising from experimental evidence are accommodated. The code BRAGFLO calculates the gas pressure, brine mass, gas volume, and mass of remaining Fe and cellulosics for each time step and computational cell. The total CO{sub 2} in the repository and dissolved Ca(OH){sub 2} is estimated. Lookup tables are constructed for pmH and f(CO{sub 2}) as a function of brine type and volume, moles of CO{sub 2}, and Ca(OH){sub 2}. Amounts of five soluble complexants are considered. A model based on the formulation of Harvie et al. produces tables of solubilities for each actinide oxidation state as a function of pmH, f(CO{sub 2}), brine composition, and complexant. Experimental data yield lookup tables of fractions of Th, U, Np, Pu, and Am in each oxidation state as a function of f(CO{sub 2}) and complexant. The tables are then used to provide a concentration of …
Date:
December 31, 1996
Creator:
Weiner, R.F.; Stockman, C.T.; Wang, Y. & Novak, C.F.
Object Type:
Article
System:
The UNT Digital Library
Conclusions of the workshop
During this Workshop, it was concluded that a Proton-Proton Collider with an energy of 100 TeV per beam and a luminosity of about 10{sup 35} cm{sup {minus}2} s{sup {minus}1} is feasible. The most important technical requirement for the realization of such a project is a large bending field. For instance, a field of 13 Tesla would be desirable. This is twice the field of the SSC superconducting magnets, which very likely may be achieved in a non-too-far future by extrapolation of the present technology. The design of this Collider would follow very closely the methods used for the design of the SSC and of the LHC, with the major noticeable difference that, because of the larger bending field and the larger beam energy, the performance is determined by the effects of the Synchrotron Radiation in the similar manner they affect the performance of an electron-positron collider. This fact has considerable beneficial consequences since it allows the attainment of large luminosity by reducing the beam dimensions at collision and by requiring, to some degree, less number of particles per beam. On the other end, the losses to synchrotron radiation are to be absorbed by the cryogenic system, and the vacuum system …
Date:
December 31, 1996
Creator:
Ruggiero, Alessandro G.
Object Type:
Article
System:
The UNT Digital Library
Condensed argon isentropic compression with ultrahigh magnetic field pressure: Experimental design. Post-shot report
This report continues the series of work devoted to experimental study of a high-dense condensed argon state. Remember that according to work of Kwon et. al., hexagonal close-packed structure is profitable in terms of energy rather than face-centered argon structure (stable with zero pressure). What is most interesting and intriguing here is the issue of possible argon metallization, when it is compressed up to the densities more than 9.17 g/cm{sup 3}. In the experiment of 1995 (the arrangement and data are described in a cited reference) the authors recorded appearance of conductivity in argon, which is non-conductive in the initial state, when it is compressed more than a factor of four. The peak value of argon specific conductivity recorded in this experiment did not exceed 10 (Ohm x cm){sup {minus}1}. This value of conductivity is characteristic of semiconductors, but not metals, which have 10{sup 4} (Ohm x cm){sup {minus}1}. At this stage of the work the main attention is paid to recording of argon conductive state and studying the possibilities of multiframed radiography of the sample in the compressed state.
Date:
December 31, 1996
Creator:
Bykov, A.I.; Boriskov, G.V.; Dolotenko, M.I. & others], and
Object Type:
Report
System:
The UNT Digital Library
Conduction band states and the 5d-4f laser transition of rare earth ion dopants
We discuss how the interactions of the 5d orbital with the conduction band of the host medium play a crucial role in determining whether rare earth containing materials can serve as useful laser materials, based on their 5d-4f transition. To explore this issue, we examine the pump-probe spectra of Sm[sup 2+], Eu[sup 2+], and Ce[sup 3+] dopants in various fluoride and chloride crystals. In addition we suggest that the luminescence properties are also profoundly impacted by this interaction. The outstanding UV laser performance achieved by the Ce:LiSrAlF[sub 6] crystal is rationalized in terms of the reduced overlap of conduction band states with the cerium ions.
Date:
December 31, 1996
Creator:
Payne, S. A.; Marshall, C. D.; Bayramian, A. & Lawson, J. K.
Object Type:
Article
System:
The UNT Digital Library
Configurational diffusion of asphaltenes in fresh and aged catalyst extrudates. Quarterly progress report, June 20--September 30, 1996
The objective of this research is to determine the relationship between the size and shape of coal and petroleum macromolecules and their diffusion rates i.e., effective diffusivities, in catalyst pore structures. That is, how do the effective intrapore diffusivities depend on molecule configuration and pore geometry. The study involves three tasks: Relationship between effective intrapore diffusion coefficients, molecular size, and pore geometry; Effects of solvent composition, solute concentration, and temperature on the molecular configuration and diffusion rate of coal and petroleum asphaltenes in catalyst pores; and Assessment of diffusional limitations in aged catalysts. This quarter, uptake experiments of coal and petroleum asphaltenes into porous catalyst were performed using different initial concentrations, temperatures, and solvents. The adsorption-diffusion parameters were obtained by simulating the experimental data with the mathematical model. The results showed that the adsorption constants for coal asphaltene fractions at 0.5 mg/cm{sup 3} initial concentration are less than those at 0.05 mg/cm{sup 3}, indicating the non-linearity of coal asphaltene adsorption on porous catalyst. Comparison of uptake results using different solvents showed that the adsorption constants with solvent toluene are much larger than those with THF solvent. The effect of temperature on the adsorptive uptake was complex, with the adsorptivity for …
Date:
December 31, 1996
Creator:
Guin, J.A.
Object Type:
Report
System:
The UNT Digital Library
Confinement, diquarks and goldstone`s theorem
Determinations of the gluon propagator in the continuum and in lattice simulations are compared. A systematic truncation procedure for the quark Dyson-Schwinger and bound state Bethe-Salpeter equations is described. The procedure ensures the flavor-octet axial- vector Ward identity is satisfied order-by-order, thereby guaranteeing the preservation of Goldstone`s theorem; and identifies a mechanism that simultaneously ensures the absence of diquarks in QCD and their presence in QCD{sup N{sub c}=2}, where the color singlet diquark is the ``baryon`` of the theory.
Date:
December 31, 1996
Creator:
Roberts, C.D.
Object Type:
Article
System:
The UNT Digital Library
Consensus implementation of a groundwater remediation project at the Idaho National Engineering Laboratory
Because of significant characterization uncertainties existing when the Record of Decision was signed and the unfavorable national reputation of groundwater pump and treat remediation projects, the Test Area North (TAN) groundwater ROD includes the evaluation of five emerging technologies that show potential for treating the organic contamination in situ or reducing the toxicity of contaminants above ground. Treatability studies will be conducted to ascertain whether any may be suitable for implementation at TAN to yield more timely or cost effective restoration of the aquifer. The implementation approach established for the TAN groundwater project is a consensus approach, maximizing a partnership relation with stakeholders in constant, iterative implementation decision making.
Date:
December 31, 1996
Creator:
Hastings, K.R. & Carlson, D.S.
Object Type:
Article
System:
The UNT Digital Library
Considerations for patient positioning in static beams for BNCT
The objective of this short communication is to provide a guideline for patient positioning, verification, and immobilization for boron neutron capture therapy.
Date:
December 31, 1996
Creator:
Wielopolski, L., Capala, J., Pendzick, N.E., Chanana, A.D., & Chadha, M.
Object Type:
Article
System:
The UNT Digital Library
Construction of a genome-wide human BAC-Unigene resource. Final progress report, 1989--1996
Currently, over 30,000 mapped STSs and 27,000 mapped Unigenes (non-redundant, unigene sets of cDNA representing EST clusters) are available for human alone. A total of 44,000 Unigene cDNA clones have been supplied by Research Genetics. Unigenes, or cDNAs are excellent resource for map building for two reasons. Firstly, they exist in two alternative forms -- as both sequence information for PCR primer pairs, and cDNA clones -- thus making library screening by colony hybridization as well as pooled library PCR possible. The authors have developed an efficient and robust procedure to screen genomic libraries with large number of DNA probes. Secondly, the linkage and order of expressed sequences, or genes are highly conserved among human, mouse and other mammalian species. Therefore, mapping with cDNA markers rather than random anonymous STSs will greatly facilitate comparative, evolutionary studies as well as physical map building. They have currently deconvoluted over 10,000 Unigene probes against a 4X coverage human BAC clones from the approved library D by high density colony hybridization method. 10,000 batches of Unigenes are arrayed in an imaginary 100 X 100 matrix from which 100 row pools and 100 column pools are obtained. Library filters are hybridized with pooled probes, thus …
Date:
December 31, 1996
Creator:
Lim, C.S.; Xu, R.X. & Wang, M.
Object Type:
Report
System:
The UNT Digital Library
Contact-cooled U-monochromators for high heat load x-ray beamlines
This paper describes the design, expected performance, and preliminary test results of a contact-cooled monochromator for use on high heat load x-ray beamlines. The monochromator has a cross section in the shape of the letter U. This monochromator should be suitable for handing heat fluxes up to 5 W/square millimeter. As such, for the present application, it is compatible with the best internally cooled crystal monochromators. There are three key features in the design of this monochromator. First, it is contact cooled, thereby eliminating fabrication of cooling channels, bonding, and undesirable strains in the monochromator due to coolant-manifold-to-crystal-interface. Second, by illuminating the entire length of the crystal and extracting the central part of the reflected beam, sharp slope changes in the beam profile and thus slope errors are avoided. Last, by appropriate cooling of the crystal, tangential slope error can be substantially reduced.
Date:
December 31, 1996
Creator:
Khounsary, A.; Yun, W.; Trakhtenberg, E.; Xu, S.; Assoufid, L. & Lee, W. K.
Object Type:
Article
System:
The UNT Digital Library