Effects of catalytic mineral matter on CO/CO sub 2 , temperature and burning time for char combustion (open access)

Effects of catalytic mineral matter on CO/CO sub 2 , temperature and burning time for char combustion

The temperature of a char particle burning in an oxygen containing atmosphere is the product of a strongly coupled balance between particle size and physical properties, heat transfer from the particle, surface reactivity, CO/CO{sub 2} ratio and gas phase diffusion in the surrounding boundary layer and within the particle. CO{sub 2}/CO ratios can be strongly influenced by catalytic material in the carbon and by the char temperature. In this program we are measuring the CO{sub 2}/CO ratio for both catalyzed and uncatalyzed chars over a wide range of temperature. These results will then be used to develop predictive models for char temperature and burning rates. The electrodynamic balance has been successfully used to make such measurements for single 200{mu}m spherocarb particles. A few theoretical approaches to model a single particle oxidation have been made, but most of them assumed the infinitely thin reaction zone at the particle surface. This approach can not explain pore diffusion limitation, structural change, or reaction at low temperatures inside the particle. Too simplifying solid phase reaction may leads to wrong predictions. In this report, progress on constructing models including both solid and gas phase reaction are reported.
Date: May 4, 1992
Creator: Longwell, J. P.; Sarofim, A. F.; Lee, Chun-Hyuk & Modestino, A. J.
Object Type: Report
System: The UNT Digital Library
NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts (open access)

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts

During this period, we focused our attention in analyzing the magnetic nature of the extensively used trimetallic catalyst system Cu-Co-Cr for the production of higher alcohols. We believe that there could be some correspondence between the catalytic and magnetic behaviors of the transition metal catalyst systems. Both the morphology and metallic charge distribution of the particles are known to govern the catalytic as well as the magnetic properties of the system.
Date: May 4, 1992
Creator: Murty, A.N.
Object Type: Report
System: The UNT Digital Library
Soft x-ray detection with diamond photoconductive detectors (open access)

Soft x-ray detection with diamond photoconductive detectors

Photoconductive detectors fabricated from natural lla diamonds have been used to measure the x-ray power emitted from laser produced plasmas. The detector was operated without any absorbing filters to distort the x-ray power measurement. The 5.5 eV bandgap of the detector material practically eliminates its sensitivity to scattered laser radiation thus permitting filterless operation. The detector response time or carrier life time was 90 ps. Excellent agreement was achieved between a diamond PCD and a multichannel photoemissive diode array in the measurement of radiated x-ray power and energy. 4 figs.
Date: May 4, 1990
Creator: Kania, D. R.; Pan, L.; Kornblum, H.; Bell, P.; Landen, O. N. & Pianetta, P.
Object Type: Article
System: The UNT Digital Library
Sitewide Environmental Assessment for the National Renewable Energy Laboratory, Golden, Colorado (open access)

Sitewide Environmental Assessment for the National Renewable Energy Laboratory, Golden, Colorado

The Solar Energy Research, Development, and Demonstration Act of 1974 authorized a federal program to develop solar energy as a viable source of the nation`s future energy needs. Under this authority, the National Renewable Energy Laboratory (NREL) was created as a laboratory of the Department of Energy (DOE) to research a number of renewable energy possibilities. The laboratory conducts its operations both in government-owned facilities on the NREL South Table Mountain (STM) Site near Golden, Colorado, and in a number of leased facilities, particularly the Denver West Office Park. NREL operations include research in energy technologies, and other areas of national environmental and energy technology interest. Examples of these technologies include electricity from sunlight with solar cells (photovoltaics); energy from wind (windmills or wind turbines); conversion of plants and plant products (biomass) into liquid fuels (ethanol and methanol); heat from the sun (solar thermal) in place of wood, oil, gas, coal and other forms of heating; and solar buildings. NREL proposes to continue and expand the present R&D efforts in C&R energy by making infrastructure improvements and constructing facilities to eventually consolidate the R&D and associated support activities at its STM Site. In addition, it is proposed that operations continue …
Date: May 4, 1993
Creator: unknown
Object Type: Report
System: The UNT Digital Library
NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, December 15, 1991--March 15, 1992 (open access)

NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, December 15, 1991--March 15, 1992

During this period, we focused our attention in analyzing the magnetic nature of the extensively used trimetallic catalyst system Cu-Co-Cr for the production of higher alcohols. We believe that there could be some correspondence between the catalytic and magnetic behaviors of the transition metal catalyst systems. Both the morphology and metallic charge distribution of the particles are known to govern the catalytic as well as the magnetic properties of the system.
Date: May 4, 1992
Creator: Murty, A. N.
Object Type: Report
System: The UNT Digital Library
Environmental Hazards Assessment Program. Quarterly report, January 1994--March 1994 (open access)

Environmental Hazards Assessment Program. Quarterly report, January 1994--March 1994

The objectives of the EHAP program are to: Develop a holistic, national basis for risk assessment, risk management and risk communication; Develop a pool of talented scientists and experts in cleanup activities, especially in human health aspects, and; Identify needs and develop programs addressing the critical shortage of well-educated, highly-skilled technical and scientific personnel to address the health oriented aspects of environmental restoration and waste management. This report describes activities and reports on progress for the third quarter of year two (January-March, 1994) of the grant. To better accomplish objectives, grant efforts are organized into three major elements: The Crossroads of Humanity Series; Research, Science and Education Programs; and Program Management. The Crossroads of Humanity Series charted a new course, incorporating lessons learned during previous quarters into a series of programs designed to address environmental issues in a real world setting. Reports are included on the various research programs with milestones and deliverables from the third quarter.
Date: May 4, 1994
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Fundamental studies of coal liquefaction. Quarterly report No. 6, January 1--April 1, 1993 (open access)

Fundamental studies of coal liquefaction. Quarterly report No. 6, January 1--April 1, 1993

Figures 3, 4, and 5 display images of two adjacent particles chosen for analysis with characteristic dimensions of 50--100 {mu}m Figure 3 shows that there is essentially no change up to 395{degrees}C over an 18 min period, but at that point the particle labeled a begins to shrink. The action continues in Figure 4 where the particle contracts to about half its initial size over a 45 sec period as the temperature, increases from 424{degrees}C to 430{degrees}C, at which point the contraction stops. The size profile for a is presented in Figure 6 and compares very well with the profile generated in an earlier experiment from our last report. As just noted, this agreement suggests that this behavior is representative of at least one class of particle in the sample. Figure 5 shows that there is a second, higher temperature range of activity, represented by the changes in particle b. This particle contracts to about half its size from 450{degrees} to 460{degrees}C over 1 min. The temperature was held at 460{degrees} and there appears to be an additional 7--10% contraction over 10 min at that temperature, although the scatter seen in Figure 6 shows that change is not outside our …
Date: May 4, 1993
Creator: Ross, D. S.
Object Type: Report
System: The UNT Digital Library
The liquid helium thermosyphon for the GEM detector magnet (open access)

The liquid helium thermosyphon for the GEM detector magnet

The GEM detector magnet, a horizontal solenoid 19.5 m in diameter and wound with a niobium-titanium cable in conduit, will be located with it`s axis 19.5 m below grade. The conductor is wound on the inside of an aluminum bobbin which is cooled by liquid helium which flows by natural convection in a thermosyphon loop from a large storage dewar located at the ground surface. The function of the thermosyphon system is to absorb the environmental heat load as well as any internally generated heat. In the first category is included that heat which is transfered to the magnet by way of the mechanical supports, the insulation and the current leads. The internally generated heat includes the resistive heating within the normally conducting conductor splices and the inductive heating of the bobbin during current transients. Though similar systems have been employed elsewhere, there are some unique aspects to the present design. By taking advantage of the large vertical head available, the parallel heat exchanger passes within the magnet remain sub-cooled, thus insuring single phase coolant within the magnet. It is believed that this will be the first instance of such a large vertical head being used to this advantage in …
Date: May 4, 1993
Creator: Warren, R. P.
Object Type: Article
System: The UNT Digital Library
Crystalline beams: The vertical zigzag (open access)

Crystalline beams: The vertical zigzag

This note is the continuation of our comprehensive investigation of Crystalline Beams. After having determined the equations of motion and the conditions for the formation of the simplest configuration, i.e. the string, we study the possibility of storing an intense beam of charged particles in a storage ring where they form a vertical zigzag. We define the equilibrium configuration, and examine the confinement conditions. Subsequently, we derive the transfer matrix for motion through various elements of the storage ring. Finally we investigate the stability conditions for such a beam.
Date: May 4, 1994
Creator: Haffmans, A. F.; Maletic, D. & Ruggiero, A. G.
Object Type: Report
System: The UNT Digital Library
Effects of catalytic mineral matter on CO/CO{sub 2}, temperature and burning time for char combustion. Quarterly progress report No. 10, January--March 1992 (open access)

Effects of catalytic mineral matter on CO/CO{sub 2}, temperature and burning time for char combustion. Quarterly progress report No. 10, January--March 1992

The temperature of a char particle burning in an oxygen containing atmosphere is the product of a strongly coupled balance between particle size and physical properties, heat transfer from the particle, surface reactivity, CO/CO{sub 2} ratio and gas phase diffusion in the surrounding boundary layer and within the particle. CO{sub 2}/CO ratios can be strongly influenced by catalytic material in the carbon and by the char temperature. In this program we are measuring the CO{sub 2}/CO ratio for both catalyzed and uncatalyzed chars over a wide range of temperature. These results will then be used to develop predictive models for char temperature and burning rates. The electrodynamic balance has been successfully used to make such measurements for single 200{mu}m spherocarb particles. A few theoretical approaches to model a single particle oxidation have been made, but most of them assumed the infinitely thin reaction zone at the particle surface. This approach can not explain pore diffusion limitation, structural change, or reaction at low temperatures inside the particle. Too simplifying solid phase reaction may leads to wrong predictions. In this report, progress on constructing models including both solid and gas phase reaction are reported.
Date: May 4, 1992
Creator: Longwell, J. P.; Sarofim, A. F.; Lee, Chun-Hyuk & Modestino, A. J.
Object Type: Report
System: The UNT Digital Library
Chemical compatibility of tank wastes in tanks 241-C-106, 241-AY-101, and 241-AY-102. Revision 1 (open access)

Chemical compatibility of tank wastes in tanks 241-C-106, 241-AY-101, and 241-AY-102. Revision 1

This report documents the chemical compatibility of waste types within tanks 241-C-106, 241-AY-101, and 241-AY-102. This information was compiled to facilitate the transfer of tank 241-C-106 waste to tank 241-AY-102 utilizing supernatant from tank 241-AY-101 as the sluicing medium. This document justifies that no chemical compatibility safety issues currently understood, or theorized from thermodynamic modeling, will result from the intended sluice transfer operation.
Date: May 4, 1994
Creator: Sederburg, J. P.
Object Type: Report
System: The UNT Digital Library
45-Day safety screen results for Tank 241-U-201, push mode, cores 70, 73 and 74 (open access)

45-Day safety screen results for Tank 241-U-201, push mode, cores 70, 73 and 74

Three core samples, each having two segments, from Tank 241-U-201 (U-201) were received by the 222-S Laboratories. Safety screening analysis, such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and total alpha activity were conducted on Core 70, Segment 1 and 2 and on Core 73, Segment 1 and 2. Core 74, Segment 1 and 2 were taken to test rotary bit in push mode sampling. No analysis was requested on Core 74, Segment 1 and 2. Analytical results for the TGA analyses for Core 70, Segment 1, Upper half solid sample was less than the safety screening notification limit of 17 percent water. Notification was made on April 27, 1995. No exotherm was associated with this sample. Analytical results are presented in Tables 1 to 4, with the applicable notification limits shaded.
Date: May 4, 1995
Creator: Sathyanarayana, P.
Object Type: Report
System: The UNT Digital Library
Microstructural examination of irradiated V-(4-5%)Cr-(4-5%)Ti. (open access)

Microstructural examination of irradiated V-(4-5%)Cr-(4-5%)Ti.

Microstructural examination results are reported for two heats of V-(4-5%) Cr-(4-5%)Ti irradiated in the EBR-II X530 experiment to 4.5 dpa at {approximately}400 C to provide an understanding of the microstructural evolution that may be associated with degradation of mechanical properties. Fine precipitates were observed in high density intermixed with small defect clusters for all conditions examined following the irradiation. The irradiation-induced precipitation does not appear to be affected by preirradiation heat treatment at 950-1125 C. There was no evidence for a significant density of large (diameter >10 nm) dislocation loops or network dislocations. Analytical investigations successfully demonstrated that the precipitates were enriched in titanium, depleted in vanadium and contained no nitrogen. These results are discussed in terms of future alloy development options.
Date: May 4, 1998
Creator: Gelles, D. S.
Object Type: Article
System: The UNT Digital Library
Lithium-endohedral C{sub 60} complexes. (open access)

Lithium-endohedral C{sub 60} complexes.

High capacity, reversible, lithium intercalated carbon anodes have been prepared, 855 m.Ah/g, which exceed the capacity for stage 1 lithium intercalated carbon anodes, 372 mAh/g. Since there is very little hydrogen content in the high capacity anode, the fullerene C{sub 60} lattice is used to investigate the nature of lithium ion bonding and spacing between lithiums in endohedral lithium complexes of C{sub 60}. Three lithium-endohedral complexes have been investigated using ab initio molecular orbital calculations involving 2,3 and 5 lithium. The calculated results suggest that lithium cluster formation may be important for achieving the high capacity lithium carbon anodes.
Date: May 4, 1998
Creator: Scanlon, L. G.
Object Type: Article
System: The UNT Digital Library
EPR detection of light-generated nuclear coherences in photosynthetic reaction centers. (open access)

EPR detection of light-generated nuclear coherences in photosynthetic reaction centers.

In this study we first discuss a pulsed EPR experiment designed to establish the mechanism of coherence generation [1]. The pulse sequence employed, flash-t-({pi}/2){sub x}-{tau}, consists of a short laser pulse at time zero, followed by a variable period t. At the end of this period a non-ideal ({pi}/2) microwave pulse is applied. The resulting free-induction decay at fixed detection time {tau} is then monitored as a function of successively incremented values of t. For P{sub 700}{sup +} A{sub 1}{sup {minus}} in deuterated and {sup 15}N-substituted PSI preparations, the transverse magnetization shows an oscillatory dependence on the delay between the laser and the microwave pulse [1]. Apparently, there are fast initial oscillations which disappear 250 ns after the laser pulse. In addition, slow persisting oscillations with frequencies of a few MHz can be observed. Basically, these slow oscillations represent nuclear coherences initiated by the laser pulse [1].
Date: May 4, 1998
Creator: Bechtold, M.
Object Type: Article
System: The UNT Digital Library
Characterization of spent EBR-II driver fuel. (open access)

Characterization of spent EBR-II driver fuel.

Operations and material control and accountancy requirements for the Fuel Conditioning Facility demand accurate prediction of the mass flow of spent EBR-II driver fuel into the facility. This requires validated calculational tools that can predict the burnup and isotopic distribution in irradiated Zr-alloy fueled driver assemblies. Detailed core-follow depletion calculations have been performed for an extensive series of EBR-II runs to produce a database of material inventories for the spent fuel to be processed. As this fuel is processed, comparison of calculated values with measured data obtained from samples of this fuel is producing a growing set of validation data. A more extensive set of samples and measurements from the initial processing of irradiated driver fuel has produced valuable estimates of the biases and uncertainties in both the measured and calculated values. Results of these comparisons are presented herein and indicate the calculated values adequately predict the mass flows.
Date: May 4, 1998
Creator: McKnight, R. D.
Object Type: Article
System: The UNT Digital Library
Nucleation of nanocrystalline diamond by fragmentation of fullerene precursors. (open access)

Nucleation of nanocrystalline diamond by fragmentation of fullerene precursors.

Growth of diamond films from C{sub 60}/Ar microwave discharges results in a nanocrystalline microstructure with crystallite sizes in the range 3-10 nm. Heterogeneous nucleation rates of 10{sup 10} cm{sup {minus}2} sec are required to account for the results. The nucleation mechanism presented here fulfills this requirement and is based on the insertion of carbon dimer, C{sub 2}, molecules, produced by fragmentation of C{sub 60}, into the n-bonded dimer rows of the reconstructed (100) surface of diamond. Density functional theory is used to calculate the energetic of C{sub 2} insertion into carbon clusters that model the (100) surface. The reaction of singlet C{sub 2} with the double bond of the C{sub 9}H{sub 12} cluster leads to either carbene structures or a cyclobutynelike structure. At the HF/6-31G* level, the carbene product has a C{sub 2v} structure, while at the B3LYP/6-31G* levels of theory, it has a C{sub s} structure with the inserted C{sub 2} tilted. No barrier for insertion into the C=C double bond of the C{sub 9}H{sub 12} cluster was found at the HF/6-31G* and B3LYP/6-31G* levels of theory. Thus, calculations including correlation energy and geometry optimization indicate that insertion of C{sub 2} into a C=C double bond leads to a …
Date: May 4, 1998
Creator: Gruen, D. M.
Object Type: Article
System: The UNT Digital Library
Fermilab Library Directions (open access)

Fermilab Library Directions

In this document, we indicate our current thinking about the directions of the Fermilab Library. The ideas relate to the preprint management issue in a number of ways. The ideas are subject to revision as we come to understand what is possible as well as what is needed by the Laboratory community. This document should therefore be regarded as our personal view--the availability of off-the-shelf technology, of funding as well as feedback from the laboratory community about their needs will all affect how far we actually proceed in any of these directions.
Date: May 4, 1990
Creator: Garrett, P. & Ritchie, D.
Object Type: Article
System: The UNT Digital Library
Stark-effect measurement of high FEL (free-electron laser) electric fields in MTX (Microwave Tokamak Experiment) by laser-aided particle-probe spectroscopy (open access)

Stark-effect measurement of high FEL (free-electron laser) electric fields in MTX (Microwave Tokamak Experiment) by laser-aided particle-probe spectroscopy

We are constructing a diagnostic system to measure the electric field (>100 kV/cm) of a free-electron laser (FEL) beam when injected into the plasma of the Microwave Tokamak Experiment (MTX). The apparatus allows a crossed-beam measurement, with 2-cm spatial resolution in the plasma, involving the FEL beam (with 140-GHz, {approx}1-GW ECH pulses), a neutral-helium beam, and a dye-laser beam. After the laser beam pumps metastable helium atoms to higher excited states, their decay light is detected by a collimated optical system. Because of the Stark effect due to the FEL electric field ({rvec E}), a forbidden transition can be strongly induced. The intensity of emitted light resulting from the forbidden transition is proportional to E{sup 2}. Because photon counting rates are calculated to be low, extra effort is made to minimize background and noise levels. It is possible that the lower {rvec E} of an MTX gyrotron-produced ECH beam with its longer-duration pulses also can be measured using this method. Other applications may include measurements of ion temperature (using charge-exchange recombination), edge-density fluctuations, and core impurity concentrations. 11 refs., 2 figs., 2 tabs.
Date: May 4, 1990
Creator: Oda, T.; Takiyama, K.; Odajima, K.; Ohasa, K.; Shiho, M.; Mizuno, K. et al.
Object Type: Article
System: The UNT Digital Library
Thomson scattering diagnostic for the Microwave Tokamak Experiment (open access)

Thomson scattering diagnostic for the Microwave Tokamak Experiment

The Thomson-scattering diagnostic system (TSS) on the Microwave Tokamak Experiment (MTX) at LLNL routinely monitors electron temperature (T{sub e}) and density. Typical measured values at the plasma center under clean conditions are 900 {plus minus} 70 eV and 1 to 2 {times} 10{sup 14} ({plus minus}30%) cm{sup {minus}3}. The TSS apparatus is compact, with all elements mounted on one sturdy, two-level optics table. Because of this, we maintain with minimum effort the alignment of both the ruby-laser input optics and the scattered-light collecting optics. Undesired background signals, e.g., plasma light as well as ruby-laser light scattered off obstacles and walls, are generally small compared with the Thomson-scattered signals we normally detect. In the MTX T{sub e} region, the TSS data are definitely fitted better when relativistic effects are included in the equations. Besides determining the temperature of the Maxwellian electron distribution, the system is designed to detect electron heating from GW-level free-electron laser (FEL) pulses by measuring large wavelength shifts of the scattered laser photons. TSS data suggest that we may indeed by able to detect these electrons, which can have energies up to 10 keV, according to computer simulation. 7 refs., 4 figs.
Date: May 4, 1990
Creator: Foote, J.H.; Barter, J.D.; Sewall, N.R.; Jolly, J.J. & Schlander, L.F.
Object Type: Article
System: The UNT Digital Library
Modeling of hydrologic conditions and solute movement in processed oil shale waste embankments under simulated climatic conditions. Second quarterly report, January 1, 1992--March 31, 1992 (open access)

Modeling of hydrologic conditions and solute movement in processed oil shale waste embankments under simulated climatic conditions. Second quarterly report, January 1, 1992--March 31, 1992

The scope of the research program and the continuation is to study interacting hydrologic, geotechnical, and chemical factors affecting the behavior and disposal of combusted processed oil shale. The research combines bench-scale testing with large scale research sufficient to describe commercial scale embankment behavior. The large scale approach was accomplished by establishing five lysimeters, each 7.3 {times} 3.0 {times} 3.0 m deep, filled with processed oil shale that has been retorted and combusted by the Lurgi-Ruhrgas (Lurgi) process. Approximately 400 tons of Lurgi processed oil shale waste was provided by Rio Blanco Oil Shale Co., Inc. (RBOSC) through a separate cooperative agreement with the University of Wyoming (UW) to carry out this study. Three of the lysimeters were established at the RBOSC Tract C-a in the Piceance Basin of Colorado. Two lysimeters were established in the Environmental Simulation Laboratory (ESL) at UW. The ESL was specifically designed and constructed so that a large range of climatic conditions could be physically applied to the processed oil shale which was filled in the lysimeter cells.
Date: May 4, 1992
Creator: Turner, J. P. & Hasfurther, V.
Object Type: Report
System: The UNT Digital Library
Modeling of hydrologic conditions and solute movement in processed oil shale waste embankments under simulated climatic conditions (open access)

Modeling of hydrologic conditions and solute movement in processed oil shale waste embankments under simulated climatic conditions

The scope of the research program and the continuation is to study interacting hydrologic, geotechnical, and chemical factors affecting the behavior and disposal of combusted processed oil shale. The research combines bench-scale testing with large scale research sufficient to describe commercial scale embankment behavior. The large scale approach was accomplished by establishing five lysimeters, each 7.3 [times] 3.0 [times] 3.0 m deep, filled with processed oil shale that has been retorted and combusted by the Lurgi-Ruhrgas (Lurgi) process. Approximately 400 tons of Lurgi processed oil shale waste was provided by Rio Blanco Oil Shale Co., Inc. (RBOSC) through a separate cooperative agreement with the University of Wyoming (UW) to carry out this study. Three of the lysimeters were established at the RBOSC Tract C-a in the Piceance Basin of Colorado. Two lysimeters were established in the Environmental Simulation Laboratory (ESL) at UW. The ESL was specifically designed and constructed so that a large range of climatic conditions could be physically applied to the processed oil shale which was filled in the lysimeter cells.
Date: May 4, 1992
Creator: Turner, J. P. & Hasfurther, V.
Object Type: Report
System: The UNT Digital Library
Experimental Study of Transition Crossing at AGS (open access)

Experimental Study of Transition Crossing at AGS

None
Date: May 4, 1996
Creator: Wei, J.
Object Type: Report
System: The UNT Digital Library
Evaluation of remaining life of the double-shell tank waste systems (open access)

Evaluation of remaining life of the double-shell tank waste systems

A remaining life assessment of the DSTs (double-shell tanks) and their associated waste transfer lines, for continued operation over the next 10 years, was favorable. The DST assessment was based on definition of significant loads, evaluation of data for possible material degradation and geometric changes and evaluation of structural analyses. The piping assessment was based primarily on service experience.
Date: May 4, 1995
Creator: Schwenk, E. B.
Object Type: Report
System: The UNT Digital Library