First-principles study of Se-intercalated graphite (open access)

First-principles study of Se-intercalated graphite

Se-intercalated graphite compounds (Se-GICs) are considered as promising candidates for room-temperature thermoelectric cooling devices. Here the authors analyze the crystallographic structure and electronic properties of these materials within the framework of density-functional theory. First, the Adaptive-Coordinate Real-space Electronic Structure (ACRES) code is used to determine the stable structure of a representative stage-2 Se-GIC by relaxing atomic positions. The stable configuration is found to be a pendant-type structure, in which each selenium is bonded covalently to two atoms within the same carbon layer, causing a local distortion of the in-plane conjugation of the graphite. Then, they use the full potential linearized augmented plane wave (FP-LAPW) method to calculate the electronic band structure of the material and discuss its properties. Near the Fermi energy E{sub F}, there are wide bands originating from the host graphitic electronic structure and a few very narrow bands mainly of Se 4p character. The latter bands contribute to high peaks in the density of states close to E{sub F}. They show that this feature, although typical of many good thermoelectrics, does not necessarily imply high thermopower in the case of Se-GICs.
Date: May 11, 2000
Creator: BARTKOWIAK,M.; MODINE,NORMAND A.; SOFO,J.O. & MAHAN,G.D.
Object Type: Article
System: The UNT Digital Library
Spent Nuclear Fuel (SNF) Project Canister Storage Building (CSB) Construction Acceptance Test Procedures (open access)

Spent Nuclear Fuel (SNF) Project Canister Storage Building (CSB) Construction Acceptance Test Procedures

None
Date: May 1, 2000
Creator: BAZINET, G.D.
Object Type: Report
System: The UNT Digital Library
Spent Nuclear Fuel (SNF) Project Canister Storage Building (CSB) Factory Acceptance Test procedures (open access)

Spent Nuclear Fuel (SNF) Project Canister Storage Building (CSB) Factory Acceptance Test procedures

None
Date: May 1, 2000
Creator: BAZINET, G.D.
Object Type: Report
System: The UNT Digital Library
Spent Nuclear Fuel (SNF) Project Canister Storage Building (CSB) Procurement Specifications [SEC 1 and 2] (open access)

Spent Nuclear Fuel (SNF) Project Canister Storage Building (CSB) Procurement Specifications [SEC 1 and 2]

This specification section defines the welding, brazing, thermal treatment, examination and testing requirements for carbon steel, and stainless steel piping.
Date: May 1, 2000
Creator: BAZINET, G.D.
Object Type: Report
System: The UNT Digital Library
Tank 241-SY-102 January 2000 Compatibility Grab Samples Analytical Results for the Final Report [SEC 1 and 2] (open access)

Tank 241-SY-102 January 2000 Compatibility Grab Samples Analytical Results for the Final Report [SEC 1 and 2]

This document is the format IV, final report for the tank 241-SY-102 (SY-102) grab samples taken in January 2000 to address waste compatibility concerns. Chemical, radiochemical, and physical analyses on the tank SY-102 samples were performed as directed in Comparability Grab Sampling and Analysis Plan for Fiscal Year 2000 (Sasaki 1999). No notification limits were exceeded. Preliminary data on samples 2SY-99-5, -6, and -7 were reported in ''Format II Report on Tank 241-SY-102 Waste Compatibility Grab Samples Taken in January 2000'' (Lockrem 2000). The data presented here represent the final results.
Date: May 11, 2000
Creator: BELL, K.E.
Object Type: Report
System: The UNT Digital Library
Calculation of Hamaker constants in non-aqueous fluid media (open access)

Calculation of Hamaker constants in non-aqueous fluid media

Calculations of the Hamaker constants representing the van der Waals interactions between conductor, resistor and dielectric materials are performed using Lifshitz theory. The calculation of the parameters for the Ninham-Parsegian relationship for several non-aqueous liquids has been derived based on literature dielectric data. Discussion of the role of van der Waals forces in the dispersion of particles is given for understanding paste formulation. Experimental measurements of viscosity are presented to show the role of dispersant truncation of attractive van der Waals forces.
Date: May 9, 2000
Creator: BELL,NELSON S. & DIMOS,DUANE B.
Object Type: Article
System: The UNT Digital Library
Meso-scale machining capabilities and issues (open access)

Meso-scale machining capabilities and issues

Meso-scale manufacturing processes are bridging the gap between silicon-based MEMS processes and conventional miniature machining. These processes can fabricate two and three-dimensional parts having micron size features in traditional materials such as stainless steels, rare earth magnets, ceramics, and glass. Meso-scale processes that are currently available include, focused ion beam sputtering, micro-milling, micro-turning, excimer laser ablation, femto-second laser ablation, and micro electro discharge machining. These meso-scale processes employ subtractive machining technologies (i.e., material removal), unlike LIGA, which is an additive meso-scale process. Meso-scale processes have different material capabilities and machining performance specifications. Machining performance specifications of interest include minimum feature size, feature tolerance, feature location accuracy, surface finish, and material removal rate. Sandia National Laboratories is developing meso-scale electro-mechanical components, which require meso-scale parts that move relative to one another. The meso-scale parts fabricated by subtractive meso-scale manufacturing processes have unique tribology issues because of the variety of materials and the surface conditions produced by the different meso-scale manufacturing processes.
Date: May 15, 2000
Creator: BENAVIDES,GILBERT L.; ADAMS,DAVID P. & YANG,PIN
Object Type: Article
System: The UNT Digital Library
Canister Storage Building (CSB) Acceptance for Beneficial Use Index Roadmap of Supporting Documents (open access)

Canister Storage Building (CSB) Acceptance for Beneficial Use Index Roadmap of Supporting Documents

None
Date: May 9, 2000
Creator: BLACK, D.M.
Object Type: Report
System: The UNT Digital Library
Transversely Polarized L Production. (open access)

Transversely Polarized L Production.

Transversely polarized {Lambda} production in hard scattering processes is discussed in terms of a leading twist T-odd fragmentation function which describes the fragmentation of an unpolarized quark into a transversely polarized {Lambda}. We focus on the properties of this function and its relevance for the RHIC and HERMES experiments.
Date: May 22, 2000
Creator: BORER, D.
Object Type: Article
System: The UNT Digital Library
Technical Evaluation for the Determination of CGI Designation for Safety Class Items Incorporated in Hose-in-Hose Transfer Line Assemblies (open access)

Technical Evaluation for the Determination of CGI Designation for Safety Class Items Incorporated in Hose-in-Hose Transfer Line Assemblies

The purpose of this technical evaluation is to determine whether the secondary hoses are to be categorized as Commercial Grade Items (CGI) or Engineered Equipment. This determination will identify whether or not use of the CGI Dedication process is appropriate.
Date: May 16, 2000
Creator: BUCHANAN, J.R.
Object Type: Report
System: The UNT Digital Library
Form factors and QCD in spacelike and timelike region (open access)

Form factors and QCD in spacelike and timelike region

The authors analyze the basic hard exclusive processes: {pi}{gamma}{sup *}{gamma}-transition, pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q{sup 2} < 0 to the timelike region q{sup 2} > 0 of the relevant momentum transfers. They describe the construction of the timelike version of the coupling constant {alpha}{sub s}. They show that due to the analytic continuation of the collinear logarithms each eigenfunction of the evolution equation acquires a phase factor and investigate the resulting interference effects which are shown to be very small. They found no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, they use a QCD sum rule inspired model and show that there are non-canceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region.
Date: May 1, 2000
Creator: Bakulev, A.P.; Radyushkin, A.V. & Stefanis, N.G.
Object Type: Article
System: The UNT Digital Library
Neurological Diagnostic Accelerometer (open access)

Neurological Diagnostic Accelerometer

None
Date: May 26, 2000
Creator: Balls, J.D.
Object Type: Report
System: The UNT Digital Library
Preferential recycling/rejection in CFBC/FBC systems using triboelectrostatic separation (open access)

Preferential recycling/rejection in CFBC/FBC systems using triboelectrostatic separation

Circulating Fluidized Bed Combustion (CFBC) and Fluidized Bed Combustion (FBC) with recirculation are widely used technologies in the US for power generation. They have the advantage of fuel flexibility, and low NO{sub x} and SO{sub x} emissions. Typically, as partially combusted fuel is circulated in the system, only a split stream of this circulating stream is rejected, with remainder recycled to the combustor. As a consequence, there is unburned carbon and partially used, valuable, calcium hydroxide in the reject stream. If these useful materials in the reject stream can be recovered and sent back to the combustor, the efficiency of the system will be increased significantly and the equivalent emissions will be lower. This project studies an innovative concept to incorporate triboelectric separation into CFBC/FBC systems in order to preferentially split its recycle/reject streams based on material compositions of the particles. The objective is to answer whether useful constituents, like carbon, calcium carbonate and calcium hydroxide or oxide, can be selectively separated from combustion ash at elevated temperatures. Laboratory experimental studies are performed at temperatures from 25 C to 210 C, the data from which are presented in the form of recovery curves. These curves present quality-versus-quantity information useful for …
Date: May 25, 2000
Creator: Ban, Heng & Stencel, J.M.
Object Type: Report
System: The UNT Digital Library
Preferential recycling/rejection in CFBC/FBC systems using triboelectrostatic separation (open access)

Preferential recycling/rejection in CFBC/FBC systems using triboelectrostatic separation

Circulating Fluidized Bed Combustion (CFBC) and Fluidized Bed Combustion (FBC) with recirculation are widely used technologies in the US for power generation. They have the advantage of fuel flexibility, and low NO{sub x} and SO{sub x} emissions. Typically, as partially combusted fuel is circulated in the system, only a split stream of this circulating stream is rejected, with remainder recycled to the combustor. As a consequence, there is unburned carbon and partially used, valuable, calcium hydroxide in the reject stream. If these useful materials in the reject stream can be recovered and sent back to the combustor, the efficiency of the system will be increased significantly and the equivalent emissions will be lower. This project studies an innovative concept to incorporate triboelectric separation into CFBC/FBC systems in order to preferentially split its recycle/reject streams based on material compositions of the particles. The objective is to answer whether useful constituents, like carbon, calcium carbonate and calcium hydroxide or oxide, can be selectively separated from combustion ash at elevated temperatures. Laboratory experimental studies are performed at temperatures from 25 C to 210 C, the data from which are presented in the form of recovery curves. These curves present quality-versus-quantity information useful for …
Date: May 25, 2000
Creator: Ban, Heng & Stencel, J.M.
Object Type: Report
System: The UNT Digital Library
Preferential recycling/rejection in CFBC/FBC systems using triboelectrostatic separation (open access)

Preferential recycling/rejection in CFBC/FBC systems using triboelectrostatic separation

Circulating Fluidized Bed Combustion (CFBC) and Fluidized Bed Combustion (FBC) with recirculation are widely used technologies in the US for power generation. They have the advantage of fuel flexibility, and low NO{sub x} and SO{sub x} emissions. Typically, as partially combusted fuel is circulated in the system, only a split stream of this circulating stream is rejected, with remainder recycled to the combustor. As a consequence, there is unburned carbon and partially used, valuable, calcium hydroxide in the reject stream. If these useful materials in the reject stream can be recovered and sent back to the combustor, the efficiency of the system will be increased significantly and the equivalent emissions will be lower. This project studies an innovative concept to incorporate triboelectric separation into CFBC/FBC systems in order to preferentially split its recycle/reject streams based on material compositions of the particles. The objective is to answer whether useful constituents, like carbon, calcium carbonate and calcium hydroxide or oxide, can be selectively separated from combustion ash at elevated temperatures. Laboratory experimental studies are performed at temperatures from 25 C to 210 C, the data from which are presented in the form of recovery curves. These curves present quality-versus-quantity information useful for …
Date: May 25, 2000
Creator: Ban, Heng & Stencel, J.M.
Object Type: Report
System: The UNT Digital Library
Metal Processing with Ultra-Short Laser Pulses (open access)

Metal Processing with Ultra-Short Laser Pulses

Femtosecond laser ablation has been shown to produce well-defined cuts and holes in metals with minimal heat effect to the remaining material. Ultrashort laser pulse processing shows promise as an important technique for materials processing. We will discuss the physical effects associated with processing based experimental and modeling results. Intense ultra-short laser pulse (USLP) generates high pressures and temperatures in a subsurface layer during the pulse, which can strongly modify the absorption. We carried out simulations of USLP absorption versus material and pulse parameters. The ablation rate as function of the laser parameters has been estimated. Since every laser pulse removes only a small amount of material, a practical laser processing system must have high repetition rate. We will demonstrate that planar ablation is unstable and the initially smooth crater bottom develops a corrugated pattern after many tens of shots. The corrugation growth rate, angle of incidence and the polarization of laser electric field dependence will be discussed. In the nonlinear stage, the formation of coherent structures with scales much larger than the laser wavelength was observed. Also, there appears to be a threshold fluence above which a narrow, nearly perfectly circular channel forms after a few hundred shots. Subsequent …
Date: May 1, 2000
Creator: Banks, P S; Feit, M D; Komashko, A M; Perry, M D; Rubenchik, A M & Stuart, B C
Object Type: Article
System: The UNT Digital Library
Energy transfer properties and mechanisms [Ion-imaging measurements of the collision step-size distribution]. Final report (open access)

Energy transfer properties and mechanisms [Ion-imaging measurements of the collision step-size distribution]. Final report

None
Date: May 15, 2000
Creator: Barker, John R.
Object Type: Report
System: The UNT Digital Library
Planning for an Integrated Research Experiment (open access)

Planning for an Integrated Research Experiment

None
Date: May 20, 2000
Creator: Barnard, J. J.; Ahle, L. E.; Bangerter, R. O.; Bieniosek, F. M.; Celata, C. M.; Faltens, A. et al.
Object Type: Article
System: The UNT Digital Library
B1 magnet harmonics (open access)

B1 magnet harmonics

During the B0 Overpass construction for the CDF detector at Fermilab, 33 B1 magnets were measured using a bucked tangential coil. Measurements were made on the midplane, at the centerline and at {+-} 1 inch horizontal displacement. Since the coil was only 62 inches long, measurements were made at four longitudinal positions. Because of the design of the Main Ring, it was sufficient to combine data from all positions and report the harmonic spectrum for the magnet as a whole. For modeling the Scrounge-atron, it is more useful to treat each measurement position separately. The author reports here an analysis of the harmonic spectra at each probe position, based on the original data.
Date: May 30, 2000
Creator: Barnes, P. D.
Object Type: Report
System: The UNT Digital Library
Groundwater monitoring plan for the Hanford Site 200 Area Treated Effluent Disposal Facility (open access)

Groundwater monitoring plan for the Hanford Site 200 Area Treated Effluent Disposal Facility

Seven years of groundwater monitoring at the 200 Area Treated Effluent Disposal Facility (TEDF) have shown that the uppermost aquifer beneath the facility is unaffected by TEDF effluent. Effluent discharges have been well below permitted and expected volumes. Groundwater mounding from TEDF operations predicted by various models has not been observed, and waterlevels in TEDF wells have continued declining with the dissipation of the nearby B Pond System groundwater mound. Analytical results for constituents with enforcement limits indicate that concentrations of all these are below Practical Quantitation Limits, and some have produced no detections. Likewise, other constituents on the permit-required list have produced results that are mostly below sitewide background. Comprehensive geochemical analyses of groundwater from TEDF wells has shown that most constituents are below background levels as calculated by two Hanford Site-wide studies. Additionally, major ion proportions and anomalously low tritium activities suggest that groundwater in the aquifer beneath the TEDF has been sequestered from influences of adjoining portions of the aquifer and any discharge activities. This inference is supported by recent hydrogeologic investigations which indicate an extremely slow rate of groundwater movement beneath the TEDF. Detailed evaluation of TEDF-area hydrogeology and groundwater geochemistry indicate that additional points of …
Date: May 17, 2000
Creator: Barnett, DB
Object Type: Report
System: The UNT Digital Library
LEDA beam diagnostics instrumentation: Beam current measurement (open access)

LEDA beam diagnostics instrumentation: Beam current measurement

None
Date: May 1, 2000
Creator: Barr, D.
Object Type: Article
System: The UNT Digital Library
Plasma-Surface Interactions on Liquids (open access)

Plasma-Surface Interactions on Liquids

Liquid plasma-facing surfaces have been suggested as an option for advanced fusion devices, particularly in regions where solid materials may not survive over long operating periods. Because liquid surfaces can be replenished, they offer the possibility of tolerating intense particle bombardment and of recovering from off-normal events. As a preliminary step in understanding the nature of plasma-surface interactions on liquids, the authors consider some of the surface processes occurring in liquids undergoing irradiation by energetic particles. These include (1) sputtering, (2) segregation of liquid component species and impurities, (3) evaporation, and (4) trapping and release of incident particles. Aspects of these processes are examined for several candidate liquids, which represent three types of low-Z liquids: pure metals (Li), metallic alloys (Sn-Li), and compound insulators (Li{sub 2}BeF{sub 4}).
Date: May 1, 2000
Creator: Bastasz, R. & Eckstein, W.
Object Type: Article
System: The UNT Digital Library
Clean Cast Steel Technology - Machinability and Technology Transfer (open access)

Clean Cast Steel Technology - Machinability and Technology Transfer

There were two main tasks in the Clean Cast Steel Technology - Machinability and Technology Transfer Project. These were (1) determine the processing facts that control the machinability of cast steel and (2) determine the ability of ladle stirring to homogenize ladle temperature, reduce the tap and pouring temperatures, and reduce casting scrap.
Date: May 1, 2000
Creator: Bates, C. E. & Griffin, J. A.
Object Type: Report
System: The UNT Digital Library
Radioactive Air Emissions Notice of Construction (NOC) for the Waste Sampling and Characterization Facility (WSCF) (open access)

Radioactive Air Emissions Notice of Construction (NOC) for the Waste Sampling and Characterization Facility (WSCF)

This NOC application is provided to update the description of amounts of material handled, and to update the calculation of potential for emissions and resultant calculation of offsite TEDE. This NOC also includes an updated description of the various emission units at WSCF, including use of portable tanks to receive and remove liquid waste contaminated with low levels of radioactive contamination. The resultant, adjusted estimate for TEDE to the hypothetical MEI due to all combined unabated emissions from WSCF is 1.4 E-02 millirem per year. The total adjusted estimate for all combined abated emissions is 2.8 E-03 millirem per year. No single emission unit at the WSCF Complex exceeds a potential (unabated) offsite dose of 2.7 E-03 millirem per year.
Date: May 1, 2000
Creator: Bates, J. A.
Object Type: Report
System: The UNT Digital Library