80 Matching Results

Search Results

Advanced search parameters have been applied.

Desulfurization of coal-derived pyrite using solutions containing dissolved oxygen. [MS Thesis]

Description: The effect of alkaline solutions containing dissolved oxygen on coal-derived pyrite was investigated in a tubular reactor. The rate of total sulfur conversion seems to be affected by oxygen partial pressure, oxygen flow rate, particle size, pyrite charge size and system temperature. A shrinking core model was chosen to represent this chemical leaching process. From the results obtained, it seems that ash or product-layer difusion is the rate-limiting step for leaching with the alkaline solution/oxygen system. The effective diffusivity is about 10/sup -5/ cm/sup 2//sec. The apparent activation energy for this process is 7.97 kcal/mole in the temperature range from 121/sup 0/ to 175/sup 0/C. For the tubular reactor system used, the rate of sulfur extraction appears to be proportional to the oxygen partial pressure. The rate of conversion increases as the oxygen flow rate decreases to a limit of 3 ml/sec. The rate also increases as the pyrite charge size decreases. The leaching solutions flow rate has a negligible effect on the total sulfur conversion.
Date: July 1, 1979
Creator: Chen, M.C.
Partner: UNT Libraries Government Documents Department

Development of enhanced heat transfer/transport/storage slurries for thermal-system improvement

Description: This paper presents a formulation of a new concept for improving thermal-system performance by utilizing the combined mechanisms of enhanced heat transfer, transport, and thermal-energy storage associated with a phase-change slurry as the working fluid.
Date: January 1, 1983
Creator: Kasza, K.E. & Chen, M.M.
Partner: UNT Libraries Government Documents Department

Mean life of the 2p/sup 4/(/sup 1/S)3s /sup 2/S state in fluorine

Description: In this work, we calculate the radiationless as well as the radiative decay rates for the 2p/sup 4/(/sup 1/S)3s /sup 2/S state. For comparison purposes, we also make similar calculations for the 2p/sup 4/(/sup 1/D)4s /sup 2/D state. Our calculation is based on the multi-configuration Dirac-Fock (MCDF) method. As spin-orbit interaction is built in, this method is capable of studying LS forbidden Auger transitions. Details of the Auger transition calculations have been given before. 9 refs.
Date: May 17, 1985
Creator: Cheng, K.T. & Chen, M.H.
Partner: UNT Libraries Government Documents Department

Assessment of impact of advanced energy transmission fluids on district heating and cooling systems (Phase 1)

Description: Argonne National Laboratory (ANL), under sponsorship of the US Department of Energy (DOE) Office of Buildings and Community Systems, has embarked upon a comprehensive, long-range program to develop high-performance advanced energy transmission fluids for use in district heating and cooling (DHC) systems. ANL has the lead technical role in this DOE program. These advanced fluids will substantially reduce flow frictional losses and enhance energy transfer. In system enhancement scoping studies conducted by ANL, the fluids yielded potentially significant upfront capital equipment cost reductions by allowing the use of smaller pipes, pumps, heat exchangers, and storage tanks as well as reductions in operational costs. This report presents the first-phase results of assessment of impact of the advanced fluids on DHC systems. Future reports will focus on assessment of impact on hardware performance, capital eqiupment, and operation costs. 9 refs., 30 figs., 2 tab.
Date: September 1, 1987
Creator: Kasza, K.E. & Chen, M.M.
Partner: UNT Libraries Government Documents Department

Collaborative research on fluidization employing computer-aided particle tracking

Description: This report covers the fourth quarter of the subject contract. The primary objective of the first year is construction of a portable computer-aided particle tracking apparatus to be used eventually at the Morgantown Energy Technology Center (METC). Third quarter effort was devoted to software development and system interconnection. These efforts continue in this quarter with hardware interface has enabled us to verify that that detectors, scalers, and discriminators are all working properly. Software debugging is now proceeding. Progress has also been made in the fabrication of the tracer particle to match the bed particles to be used at METC.
Date: January 1, 1989
Creator: Chen, M.M.
Partner: UNT Libraries Government Documents Department

Collaborative research on fluidization employing computer-aided particle tracking. [RAWCAL. EXE, PD. EXE, MAIN. EXE, PROCESS. EXE in C language]

Description: The primary objective of this work was debugging and testing of the hardware and software of the transportable computer-aided particle tracking apparatus to be used at the Morgantown Energy Technology Center. Earlier effort was devoted to system interconnection and software development. While the hardware interconnections have been finished, the software development and debugging was completed in this quarter with successful initial testing. Two tracer particles were also made from 1/8th inch nylon particles, and they will be sent to METC soon.
Date: January 1, 1989
Creator: Chen, M.M.
Partner: UNT Libraries Government Documents Department

Multiple Irradiation Capsule Experiment (MICE)-3B Irradiation Test of Space Fuel Specimens in the Advanced Test Reactor (ATR) - Close Out Documentation for Naval Reactors (NR) Information

Description: Few data exist for UO{sub 2} or UN within the notional design space for the Prometheus-1 reactor (low fission rate, high temperature, long duration). As such, basic testing is required to validate predictions (and in some cases determine) performance aspects of these fuels. Therefore, the MICE-3B test of UO{sub 2} pellets was designed to provide data on gas release, unrestrained swelling, and restrained swelling at the upper range of fission rates expected for a space reactor. These data would be compared with model predictions and used to determine adequacy of a space reactor design basis relative to fission gas release and swelling of UO{sub 2} fuel and to assess potential pellet-clad interactions. A primary goal of an irradiation test for UN fuel was to assess performance issues currently associated with this fuel type such as gas release, swelling and transient performance. Information learned from this effort may have enabled use of UN fuel for future applications.
Date: January 9, 2006
Creator: Chen, M.; Regan, CM & Noe, D.
Partner: UNT Libraries Government Documents Department

Local and Global Illumination in the Volume Rendering Integral

Description: This article is intended as an update of the major survey by Max [1] on optical models for direct volume rendering. It provides a brief overview of the subject scope covered by [1], and brings recent developments, such as new shadow algorithms and refraction rendering, into the perspective. In particular, we examine three fundamentals aspects of direct volume rendering, namely the volume rendering integral, local illumination models and global illumination models, in a wavelength-independent manner. We review the developments on spectral volume rendering, in which visible light are considered as a form of electromagnetic radiation, optical models are implemented in conjunction with representations of spectral power distribution. This survey can provide a basis for, and encourage, new efforts for developing and using complex illumination models to achieve better realism and perception through optical correctness.
Date: October 21, 2005
Creator: Max, N & Chen, M
Partner: UNT Libraries Government Documents Department

A large-scale relativistic configuration-interaction calculation for the 4s-4p and 4p-4d transition energies of copperlike heavy ions

Description: The 4s-4p and 4p-4d transition energies for high-Z copperlike ions are calculated using the relativistic configuration-interaction (RCI) method. Mass polarization (MP) and quantum electrodynamic (QED) corrections are also evaluated. For the 4s-4p transitions, the present RCI energies agree very well with results from the relativistic many-body perturbation theory. With QED and MP corrections included, our total transition energies are in very good agreement with recent high precision measurements.
Date: June 21, 2005
Creator: Cheng, K T & Chen, M H
Partner: UNT Libraries Government Documents Department

A Large-scale Relativistic Configuration-Interaction Calculation for the 4s-4p Transition Energies of Copperlike Heavy Ions

Description: The 4s-4p transition energies for high-Z copperlike ions are calculated using the relativistic configuration-interaction (RCI) method. These calculations are based on the relativistic no-pair Hamiltonian which includes Coulomb and frequency-dependent, retarded Breit interactions and use B-spline orbitals as basis functions. Mass polarization and quantum electrodynamic (QED) corrections are also calculated. The present RCI energies agree very well with results from the relativistic many-body perturbation theory. With QED corrections included, our total transition energies are in very good agreement with recent high-precision measurements.
Date: June 30, 2005
Creator: Cheng, K T & Chen, M H
Partner: UNT Libraries Government Documents Department

Hadron blind detector. Final report, FY1994 and 1995

Description: The authors have been developing a novel threshold Cherenkov detector, consisting of a gas radiator followed by a UV photosensitive wire chamber using CsI photocathodes. The photo-detector lies directly in the particle path and is thus required to have single photo-electron sensitivity and yet to be insensitive to the passage of a charged particle. In addition, the detector should be made of low mass material to minimize the effect of multiple scatterings. The proposed threshold Cherenkov counters are called Hadron Blind Detectors (HBDs) because they are blind to low energy hadrons which have lower speed {beta} for given momentum p than that of electrons. HBDs can be used in colliders, especially heavy ion hadron colliders (RHIC, LHC), which have huge {number_sign} of hadrons produced per event, to select electrons by being blind to low-momentum hadrons. The authors have studied two different methods to build HBDs described as follows: (1) windowless configuration; (2) thin window configuration. The authors describe herewith their recent experimental results on HBD research obtained with CsI photo-cathodes and HBD prototype beam testing in 1995.
Date: October 25, 1997
Creator: Chen, M.
Partner: UNT Libraries Government Documents Department

Development of Enhanced Heat Transfer/Transport/Storage Slurries for Thermal-System Improvement

Description: This report constitutes a formulation of a new concept for improving thermal-system performance by utilizing the combined mechanisms of enhanced heat transfer, transport, and thermal energy storage associated with a phase-change slurry as the working fluid. In addition, pertinent literature is surveyed and a quantitative scoping assessment of enhancement potential confirms concept merit. It has been determined that additional research and development is required in order to adequately understand the enhancement mechanisms to the degree that enhanced performance thermal systems using slurries can be designed. The concepts presented are identified as being new, rewarding research activities.
Date: June 1982
Creator: Kasza, Kenneth Edmund & Chen, M. M.
Partner: UNT Libraries Government Documents Department

Collaborative research on fluidization employing computer-aided particle tracking

Description: This report covers the sixth quarter of the subject contract. The primary objective of this quarter was modifying the software and testing the hardware of the transportable computer-aided particle tracking apparatus to be used at the Morgantown Energy Technology Center. While the data acquisition programs have been described in the last report, the program names were changed and the method for input to these programs was modified for convenient use. The hardware settings and arrangement were checked in order to obtain the optimum operating condition. 4 figs.
Date: January 1, 1990
Creator: Chen, M.M.
Partner: UNT Libraries Government Documents Department

Numerical calculation of the three dimensional electrical field in the central region of a cyclotron

Description: To provide detailed and accurate electric fields in the ion source-puller region and at the dee dummy-dee gap for a cyclotron, a relaxation method solution of Laplace's equation has been used. A conventional difference equation with variation in mesh size and relaxation factor as well as different schemes for boundary corrections have been developed to achieve roughly 1 percent accuracy for a thre-dimensional domain with 10/sup 6/ mesh points. Although the computation requires considerable computer time, it is much less expensive than electrolytic tank analogue methods for measuring field distributions around complex electrode configurations.
Date: January 1, 1981
Creator: Chen, M. & Lind, D. A.
Partner: UNT Libraries Government Documents Department

Two-Stage, Integrated, Geothermal-CO2 Storage Reservoirs: An Approach for Sustainable Energy Production, CO2-Sequestration Security, and Reduced Environmental Risk

Description: We introduce a hybrid two-stage energy-recovery approach to sequester CO{sub 2} and produce geothermal energy at low environmental risk and low cost by integrating geothermal production with CO{sub 2} capture and sequestration (CCS) in saline, sedimentary formations. Our approach combines the benefits of the approach proposed by Buscheck et al. (2011b), which uses brine as the working fluid, with those of the approach first suggested by Brown (2000) and analyzed by Pruess (2006), using CO{sub 2} as the working fluid, and then extended to saline-formation CCS by Randolph and Saar (2011a). During stage one of our hybrid approach, formation brine, which is extracted to provide pressure relief for CO{sub 2} injection, is the working fluid for energy recovery. Produced brine is applied to a consumptive beneficial use: feedstock for fresh water production through desalination, saline cooling water, or make-up water to be injected into a neighboring reservoir operation, such as in Enhanced Geothermal Systems (EGS), where there is often a shortage of a working fluid. For stage one, it is important to find economically feasible disposition options to reduce the volume of brine requiring reinjection in the integrated geothermal-CCS reservoir (Buscheck et al. 2012a). During stage two, which begins as CO{sub 2} reaches the production wells; coproduced brine and CO{sub 2} are the working fluids. We present preliminary reservoir engineering analyses of this approach, using a simple conceptual model of a homogeneous, permeable CO{sub 2} storage formation/geothermal reservoir, bounded by relatively impermeable sealing units. We assess both the CO{sub 2} sequestration capacity and geothermal energy production potential as a function of well spacing between CO{sub 2} injectors and brine/CO{sub 2} producers for various well patterns and for a range of subsurface conditions.
Date: February 2, 2012
Creator: Buscheck, T A; Chen, M; Sun, Y; Hao, Y & Elliot, T R
Partner: UNT Libraries Government Documents Department

FLYCHK: generalized population kinetics and spectral model for rapid spectroscopic analysis for all elements

Description: FLYCHK is a straightforward, rapid tool to provide ionization and population distributions of plasmas in zero dimension with accuracy sufficient for most initial estimates and in many cases applicable for more sophisticated analysis. FLYCHK solves rate equations for level population distributions by considering collisional and radiative atomic processes. The code is designed to be straightforward to use and yet is general enough to apply for most laboratory plasmas. Further, it can be applied for low-to-high Z ions and in either steady-state or time-dependent situations. Plasmas with arbitrary electron energy distributions, single or multiple electron temperatures can be studied as well as radiation-driven plasmas. To achieve this versatility and accuracy in a code that provides rapid response we employ schematic atomic structures, scaled hydrogenic cross-sections and read-in tables. It also employs the jj configuration averaged atomic states and oscillator strengths calculated using the Dirac-Hartree-Slater model for spectrum synthesis. Numerous experimental and calculational comparisons performed in recent years show that FLYCHK provides meaningful estimates of ionization distributions, well within a charge state for most laboratory applications.
Date: June 17, 2005
Creator: Chung, H; Chen, M; Morgan, W L; Ralchenko, Y & Lee, R W
Partner: UNT Libraries Government Documents Department

Soft-X-ray spectra of highly charged Os, Bi, Th, and U ions in an electron beam ion trap

Description: Systematic variation of the electron-beam energy in an electron-beam ion trap has been employed to produce soft-X-ray spectra of Os, Bi, Th, and U with highest charge states ranging up to Ni-like ions. Guided by relativistic atomic structure calculations, the strongest lines have been identified with {Delta}n = 0 (n = 4 to n' = 4) transitions in Rb- to Cu-like ions. The rather weak 4p-4d transitions are much less affected by QED contributions than the dominant 4s-4p transitions. Our wavelength measurements consequently provide benchmarks with and (almost) without QED. Because the radiative corrections are not very sensitive to the number of electrons in the valence shell, our data, moreover, provide benchmarks for the evaluation of electron-electron interactions.
Date: December 3, 2004
Creator: Trabert, E.; Beiersdorfer, P.; Fournier, K. B. & Chen, M. H.
Partner: UNT Libraries Government Documents Department