Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Volume 1, Bench-scale testing and analysis (open access)

Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Volume 1, Bench-scale testing and analysis

AMAX Research & Development Center (AMAX R&D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.
Date: May 2, 1989
Creator: Jha, M. C. & Berggren, M. H.
Object Type: Report
System: The UNT Digital Library
Tank characterization report for double-shell tank 241-AN-105 (open access)

Tank characterization report for double-shell tank 241-AN-105

A major function of the Tank Waste Remediation System (TWRS) is to characterize wastes in support of waste management and disposal activities at the Hanford Site. Analytical data from sampling and analysis, along with other available information about a tank, are compiled and maintained in a tank characterization report (TCR). This report and its appendixes serve as the TCR for double-shell tank 241-AN-105. The objectives of this report are: (1) to use characterization data in response to technical issues associated with tank 241-AN-105 waste; and (2) to provide a standard characterization of this waste in terms of a best-basis inventory estimate. The response to technical issues is summarized in Section 2.0, and the best-basis inventory estimate is presented in Section 3.0. Recommendations regarding safety status and additional sampling needs are provided in Section 4.0. Supporting data and information are contained in the appendices. This report also supports the requirements of the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1996) milestone M-44-10.
Date: May 2, 1997
Creator: Jo, J.
Object Type: Report
System: The UNT Digital Library
Multiscale finite element methods for miscible and immiscible flow in porous media (open access)

Multiscale finite element methods for miscible and immiscible flow in porous media

None
Date: May 2, 2002
Creator: Juanes, Ruben & Patzek, Tadeusz W.
Object Type: Article
System: The UNT Digital Library
Multitasking mesoporous nanomaterials for biorefinery applications (open access)

Multitasking mesoporous nanomaterials for biorefinery applications

Mesoporous silica nanoparticles (MSNs) have attracted great interest for last two decades due to their unique and advantageous structural properties, such as high surface area, pore volume, stable mesostructure, tunable pore size and controllable particle morphology. The robust silica framework provides sites for organic modifications, making MSNs ideal platforms for adsorbents and supported organocatalysts. In addition, the pores of MSNs provide cavities/ channels for incorporation of metal and metal oxide nanoparticle catalysts. These supported metal nanoparticle catalysts benefit from confined local environments to enhance their activity and selectivity for various reactions. Biomass is considered as a sustainable feedstock with potential to replace diminishing fossil fuels for the production of biofuels. Among several strategies, one of the promising methods of biofuel production from biomass is to reduce the oxygen content of the feedstock in order to improve the energy density. This can be achieved by creating C-C bonds between biomass derived intermediates to increase the molecular weight of the final hydrocarbon molecules. In this context, pore size and organic functionality of MSNs are varied to obtain the ideal catalyst for a C-C bond forming reaction: the aldol condensation. The mechanistic aspects of this reaction in supported heterogeneous catalysts are explored. The …
Date: May 2, 2013
Creator: Kandel, Kapil
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Systems Level Regulation of Rhythmic Growth Rate and Biomass Accumulation in Grasses (open access)

Systems Level Regulation of Rhythmic Growth Rate and Biomass Accumulation in Grasses

Several breakthroughs have been recently made in our understanding of plant growth and biomass accumulation. It was found that plant growth is rhythmically controlled throughout the day by the circadian clock through a complex interplay of light and phytohormone signaling pathways. While plants such as the C4 energy crop sorghum (Sorghum bicolor (L.) Moench) and possibly the C3 grass (Brachypodium distachyon) also exhibit daily rhythms in growth rate, the molecular details of its regulation remain to be explored. A better understanding of diurnally regulated growth behavior in grasses may lead to species-specific mechanisms highly relevant to future strategies to optimize energy crop biomass yield. Here we propose to devise a systems approach to identify, in parallel, regulatory hubs associated with rhythmic growth in C3 and C4 plants. We propose to use rhythmicity in daily growth patterns to drive the discovery of regulatory network modules controlling biomass accumulation.
Date: May 2, 2013
Creator: Kay, Steve A.
Object Type: Report
System: The UNT Digital Library
Technology resource document for the assembled chemical weapons assessment environmental impact statement. Vol. 5 : assembled systems for weapons destruction at Blue Grass Army Depot. (open access)

Technology resource document for the assembled chemical weapons assessment environmental impact statement. Vol. 5 : assembled systems for weapons destruction at Blue Grass Army Depot.

This volume of the Technical Resource Document (TRD) for the ''Environmental Impact Statement (EIS) for the Design, Construction and Operation of One or More Pilot Test Facilities for Assembled Chemical Weapons Destruction Technologies at One or More Sites'' (PMACWA 2001g) pertains to the destruction of assembled chemical weapons (ACW) stored in the U.S. Army's unitary chemical stockpile at Blue Grass Army Depot (BGAD), located outside Richmond, Kentucky. This volume presents technical and process information on each of the destruction technologies applicable to treatment of the specific ACW stored at BGAD. The destruction technologies described are those that have been demonstrated as part of the Assembled Chemical Weapons Assessment (ACWA) selection process (see Volume 1).
Date: May 2, 2001
Creator: Kimmell, T.; Folga, S., Frey, G.; Molberg, J.; Kier, P.; Templin, B. & Goldberg, M.
Object Type: Report
System: The UNT Digital Library
Review of the Structure of Bulk Power Markets Grid of the Future White Paper (open access)

Review of the Structure of Bulk Power Markets Grid of the Future White Paper

This paper is intended to provide an understanding of the needs of a restructured electricity market and some of the market methods and systems that have developed to address those needs. Chapter 2 discusses the historic market framework of vertically integrated utilities. Chapter 3 introduces the changes to the vertically integrated utility brought about by restructuring. It discusses generation and transmission planning, control and the regulatory process. It also summarizes reliability, security and adequacy. Chapter 4 discusses the basic structures of generation and transmission markets along with transmission-congestion contracts (TCCs) and transmission pricing principles. A discussion is given of the 12 ancillary services needed to reliably operate the power system. Chapter 4 also deals with the role of transmission in opening up markets to competition. In California increments (incs) and decrements (decs) are bid to overcome price differences in different zones caused by congestion. In PJM, any member can purchase Fixed Transmission Rights (FTRs) which allows the member to ''collect rent'' on congested lines and essentially obtain a hedge against congestion. There has been a worrisome slowdown in the growth of the transmission system in the United States since about the mid 70's. However, there are methods for providing incentives …
Date: May 2, 2000
Creator: Kirby, B.J.
Object Type: Report
System: The UNT Digital Library
Effective Communication and File-I/O Bandwidth Benchmarks (open access)

Effective Communication and File-I/O Bandwidth Benchmarks

We describe the design and MPI implementation of two benchmarks created to characterize the balanced system performance of high-performance clusters and supercomputers: b{_}eff, the communication-specific benchmark examines the parallel message passing performance of a system, and b{_}eff{_}io, which characterizes the effective 1/0 bandwidth. Both benchmarks have two goals: (a) to get a detailed insight into the Performance strengths and weaknesses of different parallel communication and I/O patterns, and based on this, (b) to obtain a single bandwidth number that characterizes the average performance of the system namely communication and 1/0 bandwidth. Both benchmarks use a time driven approach and loop over a variety of communication and access patterns to characterize a system in an automated fashion. Results of the two benchmarks are given for several systems including IBM SPs, Cray T3E, NEC SX-5, and Hitachi SR 8000. After a redesign of b{_}eff{_}io, I/O bandwidth results for several compute partition sizes are achieved in an appropriate time for rapid benchmarking.
Date: May 2, 2001
Creator: Koniges, A E & Rabenseifner, R
Object Type: Article
System: The UNT Digital Library
Sludge Batch 2 (Macrobatch 3) Rheology Studies with Simulants (open access)

Sludge Batch 2 (Macrobatch 3) Rheology Studies with Simulants

Non-radioactive sludge-only process simulations of the DWPF Sludge Receipt and Adjustment Tank (SRAT) and the Slurry Mix Evaporator (SME) cycles were conducted for a 50:50 blend of Tank 8 and Tank 40 washed sludge and Tank 40 washed sludge by itself. Rheological characterization of the sludge, SRAT product, and SME product material was requested as part of the simulant program.
Date: May 2, 2001
Creator: Koopman, D. C.
Object Type: Report
System: The UNT Digital Library
Optimum Method of Evaporator Pot Liquid Heating and Cooling for Evaporator Cleaning and Recovery Program (open access)

Optimum Method of Evaporator Pot Liquid Heating and Cooling for Evaporator Cleaning and Recovery Program

The Savannah River Site Evaporators have run with limited operation problems for almost 40 years. In October 1999, one evaporator was shut down due to the inability to lift the concentrate solutions from the pot. Different methods of pot liquid heating, cooling, and selection of optimum method were discussed.
Date: May 2, 2001
Creator: Kwon, K.C.
Object Type: Article
System: The UNT Digital Library
Fluid loads on LOFT DTT shrouds located in reactor vessel downcomer and DTT thermal loads during nuclear LOCE (open access)

Fluid loads on LOFT DTT shrouds located in reactor vessel downcomer and DTT thermal loads during nuclear LOCE

A thermal analysis was performed on a LOFT drag disc turbine (DTT) for a nuclear LOCE. Thermal gradients through the DTT shroud and turbine body, and temperature differences between body and shroud were calculated. This was done to determine the possible need for additional stress analyses of the DTT shroud to body welds based on thermal loads for a nuclear LOCE.
Date: May 2, 1978
Creator: Kyllingstad, G.
Object Type: Report
System: The UNT Digital Library
Chemical separations schemes for partitioning and transmutation systems. (open access)

Chemical separations schemes for partitioning and transmutation systems.

In the initial phase of the U.S. Accelerator Transmutation of Waste (ATW) program, a single-tier system was foreseen in which the transuranics and long-lived fission products (specifically, {sup 99}Tc and {sup 129}I) recovered from spent LWR oxide fuel would be sent directly to an accelerator-driven transmuter reactor [1]. Because the quantity of fuel to be processed annually was so large (almost 1,500 tons per year), an aqueous solvent extraction process was chosen for LWR fuel processing. Without the need to separate transuranics from one another for feed to the transmuter, it became appropriate to develop an advanced aqueous separations method that became known as UREX. The UREX process employs an added reagent (acetohydroxamic acid) that suppresses the extraction of plutonium and promotes the extraction of technetium together with uranium. Technetium can then be efficiently removed from the uranium; the recovered uranium, being highly decontaminated, can be disposed of as a low-level waste or stored in an unshielded facility for future use. Plutonium and the other transuranic elements, plus the remaining fission products, are directed to the liquid waste stream. This stream is calcined, converting the transuranics and fission products to their oxides. The resulting oxide powder, now representing only about …
Date: May 2, 2002
Creator: Laidler, J.
Object Type: Article
System: The UNT Digital Library
Hydrogen Generation Rate During Melter Feed Preparation of Tank 42 Sludge and CST in the Defense Waste Processing Facility (open access)

Hydrogen Generation Rate During Melter Feed Preparation of Tank 42 Sludge and CST in the Defense Waste Processing Facility

This document details the testing performed to determine the maximum hydrogen generation expected with a coupled flowsheet of sludge, CST, and frit.
Date: May 2, 2001
Creator: Lambert, D. P. & Monson, P. R.
Object Type: Report
System: The UNT Digital Library
AB Initio Calculations of Elastic Constants of BCC V-NB System at High Pressures (open access)

AB Initio Calculations of Elastic Constants of BCC V-NB System at High Pressures

First-principles total energy calculation based on the exact muffin-tin orbital and full potential linear muffin-tin orbital methods were used to calculate the equation of state and shear elastic constants of bcc V, Nb, and the V{sub 95}Nb{sub 05} disordered alloy as a function of pressure up to 6 Mbar. We found a mechanical instability in C{sub 44} and a corresponding softening in C at pressures {approx} 2 Mbar for V. Both shear elastic constants show softening at pressures {approx} 0.5 Mbar for Nb. Substitution of 5 at. % of V with Nb removes the instability of V with respect to trigonal distortions in the vicinity of 2 Mbar pressure, but still leaves the softening of C{sub 44} in this pressure region. We argue that the pressure induced shear instability (softening) of V (Nb) originates from the electronic system and can be explained by a combination of the Fermi surface nesting, electronic topological transition, and band Jahn-Teller effect.
Date: May 2, 2005
Creator: Landa, A; Klepeis, J; Soderlind, P; Naumov, I; Velikokhatnyi, O; Vitos, L et al.
Object Type: Article
System: The UNT Digital Library
An x-ray technique for precision laser beam synchronization (open access)

An x-ray technique for precision laser beam synchronization

A new x-ray technique for recording the relative arrival times of multiple laser beams at a common target with better than {+-} 10 ps accuracy has been implemented at the Nova laser facility. 100 ps, 3{omega} Nova beam are focused to separate locations on a gold ribbon target viewed from the side. The measurement consists of using well characterized re-entrant x-ray streak cameras for 1-dimensional streaked imaging of the > 3 keV x-rays emanating from these isolated laser plasmas. After making the necessary correction for the differential laser, x-ray and electron transit times involved, timing offsets as low as {+-} 7 ps are resolved, and on subsequent shots, corrected for, verified and independently checked. This level of synchronization proved critical in meeting the power balance requirements for indirectly-driven pulse-shaped Nova implosions.
Date: May 2, 1994
Creator: Landen, O. L.; Lerche, R. A.; Hay, R. G.; Hammel, B. A.; Kalantar, D. & Cable, M. D.
Object Type: Article
System: The UNT Digital Library
Automatically processed alpha-track radon monitor (open access)

Automatically processed alpha-track radon monitor

An automatically processed alpha-track radon monitor is provided which includes a housing having an aperture allowing radon entry, and a filter that excludes the entry of radon daughters into the housing. A flexible track registration material is located within the housing that records alpha-particle emissions from the decay of radon and radon daughters inside the housing. The flexible track registration material is capable of being spliced such that the registration material from a plurality of monitors can be spliced into a single strip to facilitate automatic processing of the registration material from the plurality of monitors. A process for the automatic counting of radon registered by a radon monitor is also provided.
Date: May 2, 1991
Creator: Langner, G. H. Jr.
Object Type: Patent
System: The UNT Digital Library
Practical Issues Associated with Mortar Projections in Large Deformation Contact/Impact Analysis (open access)

Practical Issues Associated with Mortar Projections in Large Deformation Contact/Impact Analysis

Several recent works have considered variants of the mortar-finite element method for numerical treatment of contact phenomena. The method has shown considerable promise for the spatial discretization of contact interactions, particularly for kinematically linear applications where one or both of the contacting surfaces are flat. Desirable features already demonstrated for the method in this specialized setting include passage of patch tests, preservation of convergence rates that would be obtained with a perfectly conforming mesh, and accurate resolution of contact stresses on interfaces. This paper concerns itself with the successful extension of these methods to encompass contact of geometrically noncoincident surfaces. The issue of patch test passage over curved interfaces will be discussed. It will be shown that a generalization of the mortar projection method is required to pass patch tests in this instance. Issues relating to the exact numerical integration of the mortar projection integrals will also be outlined, and a convergence study for a mortar tying application will be presented.
Date: May 2, 2002
Creator: Laursen, T. A.; Puso, M. A. & Heinstein, M. W.
Object Type: Article
System: The UNT Digital Library
HYDROGEN IGNITION MECHANISM FOR EXPLOSIONS IN NUCLEAR FACILITY PIPE SYSTEMS (open access)

HYDROGEN IGNITION MECHANISM FOR EXPLOSIONS IN NUCLEAR FACILITY PIPE SYSTEMS

Hydrogen and oxygen generation due to the radiolysis of water is a recognized hazard in pipe systems used in the nuclear industry, where the accumulation of hydrogen and oxygen at high points in the pipe system is expected, and explosive conditions exist. Pipe ruptures at nuclear facilities were attributed to hydrogen explosions inside pipelines, in nuclear facilities, i.e., Hamaoka, Nuclear Power Station in Japan, and Brunsbuettel in Germany. Prior to these accidents an ignition source for hydrogen was questionable, but these accidents, demonstrated that a mechanism was, in fact, available to initiate combustion and explosion. Hydrogen explosions may occur simultaneously with water hammer accidents in nuclear facilities, and a theoretical mechanism to relate water hammer to hydrogen deflagrations and explosions is presented herein.
Date: May 2, 2010
Creator: Leishear, R
Object Type: Article
System: The UNT Digital Library
HIGHER MODE FREQUENCY EFFECTS ON RESONANCE IN MACHINERY, STRUCTURES, AND PIPE SYSTEMS (open access)

HIGHER MODE FREQUENCY EFFECTS ON RESONANCE IN MACHINERY, STRUCTURES, AND PIPE SYSTEMS

The complexities of resonance in multi-degree of freedom systems (multi-DOF) may be clarified using graphic presentations. Multi-DOF systems represent actual systems, such as beams or springs, where multiple, higher order, natural frequencies occur. Resonance occurs when a cyclic load is applied to a structure, and the frequency of the applied load equals one of the natural frequencies. Both equations and graphic presentations are available in the literature for single degree of freedom (SDOF) systems, which describe the response of spring-mass-damper systems to harmonically applied, or cyclic, loads. Loads may be forces, moments, or forced displacements applied to one end of a structure. Multi-DOF systems are typically described only by equations in the literature, and while equations certainly permit a case by case analysis for specific conditions, graphs provide an overall comprehension not gleaned from single equations. In fact, this collection of graphed equations provides novel results, which describe the interactions between multiple natural frequencies, as well as a comprehensive description of increased vibrations near resonance.
Date: May 2, 2010
Creator: Leishear, R.
Object Type: Article
System: The UNT Digital Library
Laboratory Measurements of the Line Emission from Mid-Z L-Shell Ions in the EUV (open access)

Laboratory Measurements of the Line Emission from Mid-Z L-Shell Ions in the EUV

We are continuing EBIT measurements of line lists in the EUV region for use as astrophysical diagnostics and have recently measured the same transitions in much denser plasma of the NSTX tokamak. This allows us to calibrate density-sensitive line ratios at their upper limits. We compare our observations at low and high density with calculations from the Flexible Atomic Code.
Date: May 2, 2006
Creator: Lepson, J K; Beiersdorfer, P; Chen, H; Gu, M F & Kahn, S M
Object Type: Article
System: The UNT Digital Library
25-ps neutron detector for measuring ICF-target burn history (open access)

25-ps neutron detector for measuring ICF-target burn history

We have developed a fast, sensitive neutron detector for recording the fusion reaction-rate history of inertial-confinement fusion (ICF) experiments. The detector is based on the fast rise-time of a commercial plastic scintillator (BC-422) and has a response < 25 ps FWHM. A thin piece of scintillator material acts as a neutron-to-light converter. A zoom lens images scintillator light to a high-speed (15 ps) optical streak camera for recording. A retractable nose cone positions the scintillator between 1 and 50 cm from a target. A simultaneously recorded optical fiducial pulse allows the streak camera time base to be calibrated relative to the incident laser power. Burn histories have been measured for deuterium-tritium filled targets with yields ranging between 10{sup 8} and 2 {times} 10{sup 13} neutrons.
Date: May 2, 1994
Creator: Lerche, R. A.; Phillion, D. W. & Tietbohl, G. L.
Object Type: Article
System: The UNT Digital Library
Na2Mg2(CO3)2 double salt absorbents for CO2 removal from warm gas streams (open access)

Na2Mg2(CO3)2 double salt absorbents for CO2 removal from warm gas streams

Poster
Date: May 2, 2011
Creator: Li, L: Duan, Y.: Chen, H: Li, S: Zhang, K.
Object Type: Article
System: The UNT Digital Library
Correction to "Sound Velocities of Ferropericlase in the Earth?s Lower Mantle" (open access)

Correction to "Sound Velocities of Ferropericlase in the Earth?s Lower Mantle"

None
Date: May 2, 2007
Creator: Lin, J. F.; Jacobsen, S. D.; Sturhahn, W.; Jackson, J. M.; Zhao, J. & Yoo, C. S.
Object Type: Article
System: The UNT Digital Library
Close out of CRADA JSA 2006S008 (open access)

Close out of CRADA JSA 2006S008

Based on the JLab study and calculations, Linde made the following changes to the LR1610 heat exchanger. The LR 1610 redesign changed two different aspects of the original LR1610 design. The heat exchanger and the boiler are wrapped differently than the original LR1610 per the following: (A) Heat Exchanger - Section A - Current LR 1610 - 2 wraps - 1 path, Redesign - 2 wraps - 2 paths; Section B: Current LR 1610 - 2 wraps - 1 path, Redesign - 2 wraps - 2 paths; (B) Boiler: Current design - 1 wrap - 2 paths, Redesign - 1 wrap - 1 path. The contents of the attachments are: (1) Assembly - Pictures of the LR1610 Redesign Heat Exchanger after manufacturing; (2) Drawings - 3D and 2D drawings used to fabricate the Redesign LR1610 Heat Exchanger and the Precooler-Boiler; (3) Performance Curves - The expected performance curves and the TS diagram for a single proposed new compressor that is more capacity than the RSX; (4) Test Pictures - Set up bench test of the LR1610 Redesign Heat Exchanger; and (5) Warm Test Data - Warm N2 test data of the LR1610 Redesign Heat Exchanger. Warm test data of the …
Date: May 2, 2011
Creator: Linde
Object Type: Report
System: The UNT Digital Library