Non-Proliferative, Thorium-Based, Core and Fuel Cycle for Pressurized Water Reactors (open access)

Non-Proliferative, Thorium-Based, Core and Fuel Cycle for Pressurized Water Reactors

Two of the major barriers to the expansion of worldwide adoption of nuclear power are related to proliferation potential of the nuclear fuel cycle and issues associated with the final disposal of spent fuel. The Radkowsky Thorium Fuel (RTF) concept proposed by Professor A. Radkowsky offers a partial solution to these problems. The main idea of the concept is the utilization of the seed-blanket unit (SBU) fuel assembly geometry which is a direct replacement for a 'conventional' assembly in either a Russian pressurized water reactor (VVER-1000) or a Western pressurized water reactor (PWR). The seed-blanket fuel assembly consists of a fissile (U) zone, known as seed, and a fertile (Th) zone known as blanket. The separation of fissile and fertile allows separate fuel management schemes for the thorium part of the fuel (a subcritical 'blanket') and the 'driving' part of the core (a supercritical 'seed'). The design objective for the blanket is an efficient generation and in-situ fissioning of the U233 isotope, while the design objective for the seed is to supply neutrons to the blanket in a most economic way, i.e. with minimal investment of natural uranium. The introduction of thorium as a fertile component in the nuclear fuel …
Date: July 12, 2009
Creator: M., Todosow; M., Todosow & Raitses, G. (BNL) Galperin, A. (Ben Gurion University)
Object Type: Article
System: The UNT Digital Library
Safety Evaluation Report: Development of a Novel Efficient Solid-Oxide Hybrid for Co-generation of Hydrogen and Electricity Using Nearby Resources for Local Applications, Materials and Systems Research, Inc. (MSRI), Salt Lake City, UT, February 17, 2009 (open access)

Safety Evaluation Report: Development of a Novel Efficient Solid-Oxide Hybrid for Co-generation of Hydrogen and Electricity Using Nearby Resources for Local Applications, Materials and Systems Research, Inc. (MSRI), Salt Lake City, UT, February 17, 2009

Following a telephone interview with Materials and Systems Research, Inc. (MSRI) by members of the Hydrogen Safety Panel on December 4, 2008, a safety review team was dispatched to Salt Lake City, UT to perform a site-visit review. The major topic of concern was the presence of a hydrogen storage and dispensing shed on the MSRI premises close to both its own laboratory/office building and to the adjoining property. The metal shed contains 36 cylinders (two 18-cylinder "pods") of hydrogen all connected to a common manifold and used to supply hydrogen to a U.S. Department of Energy (DOE) fuel cell project plus several other projects using an entire pod as a common supply. In busy times, MSRI uses and replaces one pod per week. As a result of the site visit, the safety review team has raised some concern with the shed’s location, design, use, and safety features as well as other components of the facility, including the laboratory area.
Date: July 16, 2009
Creator: Barilo, Nick F.; Frikken, Don; Skolnik, Edward G. & Weiner, Steven C.
Object Type: Report
System: The UNT Digital Library
Development of Biomimetic Membranes for Near Zero PC Power Plant Emissions (open access)

Development of Biomimetic Membranes for Near Zero PC Power Plant Emissions

The first objective of this project was to develop, evaluate and compare two different CO2 separation (capture) systems. The second was to carry the preferred solution to pre-pilot development and testing. To achieve these objectives we undertook several infrastructure enabling elements: (1) development of a preferred catalyst coupled with its immobilization onto a microporous polymer membrane, (2) design and development of a microporous membrane-based, contained liquid membrane permeator and a membrane-based absorber/desorber apparatus, (3) development of a resin-wafer electrodialytic absorber/desorber apparatus, (4) development and demonstration of a pre-treatment process to condition the feed gas stream, (5) and development of computer modeling of the components and of the integrated system. The first technology was an enzyme catalyzed, membrane supported, contained liquid membrane apparatus whose gas capture was pressure/vacuum and temperature driven. A first embodiment was as a permeator, i.e. a combined absorber/desorber in a single housing. The second embodiment was as discrete absorber and desorber units. The second technology was an enzyme catalyzed, ion exchange resin wafer electrodialytically-based separation. For each of these technologies the objective was to design, manufacture, test and demonstrate the apparatus, first in the laboratory and then at pre-pilot scale, and to run it for sufficient time …
Date: July 31, 2009
Creator: Trachtenberg, Michael; Cowan, Robert; Smith, David & Sider, Ira
Object Type: Report
System: The UNT Digital Library
DEGRADATION EVALUATION OF HEAVY WATER DRUMS AND TANKS (open access)

DEGRADATION EVALUATION OF HEAVY WATER DRUMS AND TANKS

Heavy water with varying chemistries is currently being stored in over 6700 drums in L- and K-areas and in seven tanks in L-, K-, and C-areas. A detailed evaluation of the potential degradation of the drums and tanks, specific to their design and service conditions, has been performed to support the demonstration of their integrity throughout the desired storage period. The 55-gallon drums are of several designs with Type 304 stainless steel as the material of construction. The tanks have capacities ranging from 8000 to 45600 gallons and are made of Type 304 stainless steel. The drums and tanks were designed and fabricated to national regulations, codes and standards per procurement specifications for the Savannah River Site. The drums have had approximately 25 leakage failures over their 50+ years of use with the last drum failure occurring in 2003. The tanks have experienced no leaks to date. The failures in the drums have occurred principally near the bottom weld, which attaches the bottom to the drum sidewall. Failures have occurred by pitting, crevice and stress corrosion cracking and are attributable, in part, to the presence of chloride ions in the heavy water. Probable degradation mechanisms for the continued storage of …
Date: July 31, 2009
Creator: Mickalonis, J. & Vormelker, P.
Object Type: Report
System: The UNT Digital Library
Reference Binder: International Energy Agency Implementing Agreements and Annexes (open access)

Reference Binder: International Energy Agency Implementing Agreements and Annexes

Reference Binder: International Energy Agency Implementing Agreements and Annexes
Date: July 1, 2009
Creator: Evans, Meredydd; Runci, Paul J.; Meier, Alan; Delgado, Alison; Secrest, Thomas J. & Williams, Katherine
Object Type: Report
System: The UNT Digital Library
Versatile assembly of p-carboxylatocalix[4]arene-O-alkyl ethers (open access)

Versatile assembly of p-carboxylatocalix[4]arene-O-alkyl ethers

Crystallisation of lower-rim tetra-O-alkylated p-carboxylatocalix[4]arenes from pyridine results in the formation of both bi-layer and pillar type supramolecular motifs. Full alkylation at the calixarene lower rim has significant influence over the supramolecular self-assembly motif, including preclusion of pyridine guest molecules from the calixarene cavity in the solid state.
Date: July 8, 2009
Creator: Kennedy, Stuart; Teat, Simon J. & Dalgarno, Scott J.
Object Type: Article
System: The UNT Digital Library
Next Generation Hole Injection/Transport Nano-Composites for High Efficiency OLED Development (open access)

Next Generation Hole Injection/Transport Nano-Composites for High Efficiency OLED Development

The objective of this program is to use a novel nano-composite material system for the OLED anode coating/hole transport layer. The novel anode coating is intended to significantly increase not only hole injection/transport efficiency, but the device energy efficiency as well. Another goal of the Core Technologies Program is the optimization and scale-up of air-stable and cross-linkable novel HTL nano-composite materials synthesis and the development of low-cost, large-scale mist deposition processes for polymer OLED fabrication. This proposed technology holds the promise to substantially improve OLED energy efficiency and lifetime.
Date: July 31, 2009
Creator: Wang, King
Object Type: Report
System: The UNT Digital Library
Electric Power Delivery Testing Feasibility Study Task 6 Final Report (open access)

Electric Power Delivery Testing Feasibility Study Task 6 Final Report

This Final Report is covers the completion of the Electric Power Delivery Testing Feasibility Study. The objective of this project was to research, engineer, and demonstrate high-power laboratory testing protocols to accurately reproduce the conditions on the electric power grid representing both normal load switching and abnormalities such as short-circuit fault protection. Test circuits, equipment, and techniques were developed and proven at reduced power levels to determine the feasibility of building a large-scale high-power testing laboratory capable of testing equipment and systems at simulated high-power conditions of the U.S. power grid at distribution levels up through 38 kiloVolts (kV) and transmission levels up through 230 kV. The project delivered demonstrated testing techniques, high-voltage test equipment for load testing and synthetic short-circuit testing, and recommended designs for future implementation of a high-power testing laboratory to test equipment and systems, enabling increased reliability of the electric transmission and distribution grid.
Date: July 1, 2009
Creator: Tobin, Thomas
Object Type: Report
System: The UNT Digital Library
Gordon Research Conference on Radiation & Climate in 2009, July 5 -10 (open access)

Gordon Research Conference on Radiation & Climate in 2009, July 5 -10

The 2009 Gordon Research Conference on Radiation and Climate will present cutting-edge research on the outstanding issues in global climate change with focus on the radiative forcing and sensitivity of the climate system and associated physical processes. The Conference will feature a wide range of topics, including grand challenges in radiation and climate, radiative forcing, climate feedbacks, cloud processes in climate system, hydrological cycle in changing climate, absorbing aerosols and Asian monsoon, recent climate changes, and geo-engineering. The invited speakers will present the recent most important advances and future challenges in these areas. The Conference will bring together a collection of leading investigators who are at the forefront of their field, and will provide opportunities for scientists especially junior scientists and graduate students to present their work in poster format and exchange ideas with leaders in the field. The collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings, provides an avenue for scientists from different disciplines to brainstorm and promotes cross-disciplinary collaborations in the various research areas represented.
Date: July 10, 2009
Creator: Fu, Quiang
Object Type: Article
System: The UNT Digital Library
9th International Conference on Tetrapyrrole Photoreceptors of Photosynthetic Organisms (ICTPPO 2009): Meeting Proceedings (open access)

9th International Conference on Tetrapyrrole Photoreceptors of Photosynthetic Organisms (ICTPPO 2009): Meeting Proceedings

Tetrapyrroles are strongly pigmented heterocyclic molecules that play key roles in the harvesting of light and in its efficient conversion into chemical energy by photosynthetic organisms, including agronomically important plant species. This grant provided financial support for the International Conference on Tetrapyrrole Photoreceptors of Photosynthetic Organisms (ICTPPO 2009), the ninth in the series of ad hoc biennial conferences focused on the structure, function and biotechnological applications of tetrapyrrole photoreceptors, held at Asilomar Conference Center, Monterey CA from July 26 to July 31, 2009. The goal of this meeting was to bring together leading experts in the field of tetrapyrrole photoreceptors and from associated fields with new investigators, to provide critical analyses of the current state of their fields, the challenges and opportunities therein and their most recent unpublished discoveries to stimulate new approaches to address key issues of agricultural and energy significance. Among the 80 participants included 40 PIs (including one Nobelist in chemistry, two members of the US National Academy of Science, and a recent inductee to the Royal Society), 8 senior scientists, 1 DOE program manager, 12 postdoctoral fellows and 20 graduate students representing 13 countries. One third of the formal lecture program was reserved for discussion, and …
Date: July 1, 2009
Creator: Lagarias, J. Clark
Object Type: Article
System: The UNT Digital Library
Final Report for Monitoring of Reactor Antineutrinos with Compact Germanium Detectors (open access)

Final Report for Monitoring of Reactor Antineutrinos with Compact Germanium Detectors

This 2008 NCMR project has pursued measurement of the antineutrino-nucleus coherent scattering interaction using a low-energy threshold germanium gamma-ray spectrometer of roughly one-half kilogram total mass. These efforts support development of a compact system for monitoring the antineutrino emission from nuclear reactor cores. Such a monitoring system is relevant to nuclear safeguards and nuclear non-proliferation in general by adding a strong method for assuring quantitative material balance of special nuclear material in the nuclear fuel cycle used in electricity generation.
Date: July 1, 2009
Creator: Orrell, John L. & Collar, J. I.
Object Type: Report
System: The UNT Digital Library
2009 Photosynthesis to be held June 28 - July 3, 2009 (open access)

2009 Photosynthesis to be held June 28 - July 3, 2009

The capture of solar energy by photosynthesis has had a most profound influence on the development and sustenance of life on earth. It is the engine that has driven the proliferation of life and, as the source of both energy and oxygen, has had a major hand in shaping the forms that life has taken. Both ancient and present day photosynthetic carbon fixation is intimately tied to issues of immediate human concern, global energy and global warming. Decreasing our reliance on fossil fuels by tapping photosynthesis in a more direct way is an attractive goal for sustainable energy. Meeting this challenge means understanding photosynthetic energy conversion at a molecular level, a task requiring perspectives ranging through all disciplines of science. Researchers in photosynthesis have a strong history of working across conventional boundaries and engaging in multidisciplinary collaborations. The Gordon conference in photosynthesis has been a key focal point for the dissemination of new results and the establishment of powerful research collaborations. In this spirit the 2009 Gordon conference on biophysical aspects of photosynthesis will bring together top international researchers from diverse and complementary disciplines, all working towards understanding how photosynthesis converts light into the stable chemical energy that powers so …
Date: July 6, 2009
Creator: Bruce, Doug
Object Type: Article
System: The UNT Digital Library
Evolution of Safeguards over Time: Past, Present, and Projected Facilities, Material, and Budget (open access)

Evolution of Safeguards over Time: Past, Present, and Projected Facilities, Material, and Budget

This study examines the past trends and evolution of safeguards over time and projects growth through 2030. The report documents the amount of nuclear material and facilities under safeguards from 1970 until present, along with the corresponding budget. Estimates for the future amount of facilities and material under safeguards are made according to non-nuclear-weapons states’ (NNWS) plans to build more nuclear capacity and sustain current nuclear infrastructure. Since nuclear energy is seen as a clean and economic option for base load electric power, many countries are seeking to either expand their current nuclear infrastructure, or introduce nuclear power. In order to feed new nuclear power plants and sustain existing ones, more nuclear facilities will need to be built, and thus more nuclear material will be introduced into the safeguards system. The projections in this study conclude that a zero real growth scenario for the IAEA safeguards budget will result in large resource gaps in the near future.
Date: July 1, 2009
Creator: Kollar, Lenka & Mathews, Caroline E.
Object Type: Report
System: The UNT Digital Library
PREPARATION OF ANHYDROUS F-18 FLUORIDE, T. Tewson. Journal of Labelled Compounds and Radiopharmaceuticals S165; 52, Supplement 1 2009 (open access)

PREPARATION OF ANHYDROUS F-18 FLUORIDE, T. Tewson. Journal of Labelled Compounds and Radiopharmaceuticals S165; 52, Supplement 1 2009

The original specific aims of the grant where cut back considerably as the study section reduced both the time and the budget for the project. The objective of the grant was to show that fluorine-18 fluoride could be prepared completely anhydrous and thus substantially more reactive than conventionally dried fluoride using the method of Sun and DiMagno. This method involved using conventionally dried fluoride to prepare an aromatic fluoride in which the aromatic ring is substituted with electron withdrawing groups. The aryl fluoride is then dried and purified and the fluoride is displaced with an anhydrous nucleophile. Using fluorine-19 and macroscopic scale reactions the reactions work well and give anhydrous fluoride salts that are both more reactive and more selective in their reactions than conventionally dried fluoride. The original substrate chosen for the reaction was bromopentacyanobenzene (1). This compound proved to be easy to make but very hard to purify. As an alternative hexabromobenzene, which is commercially available in high purity, was tried. This reacted cleanly with conventionally dried F-18 fluoride in acetonitrile to give [{sup 18}F]-fluoropentabromobenzene (2), which could be dried by passage of the solution over alumina, which also removed any unreacted fluoride. The fluorine-18 fluoride could be …
Date: July 1, 2009
Creator: Tewson, T.
Object Type: Article
System: The UNT Digital Library
Analytical Data Report of Water Samples Collected From BP-5 Operable Unit C Well (C5859) (open access)

Analytical Data Report of Water Samples Collected From BP-5 Operable Unit C Well (C5859)

This is an analytical data report for groundwater samples received from CHPRC.
Date: July 28, 2009
Creator: Lindberg, Michael J.
Object Type: Report
System: The UNT Digital Library
Hydrogen Oxidation-Driven Hot Electron Flow Detected by Catalytic Nanodiodes (open access)

Hydrogen Oxidation-Driven Hot Electron Flow Detected by Catalytic Nanodiodes

Hydrogen oxidation on platinum is shown to be a surface catalytic chemical reaction that generates a steady state flux of hot (>1 eV) conduction electrons. These hot electrons are detected as a steady-state chemicurrent across Pt/TiO{sub 2} Schottky diodes whose Pt surface is exposed to hydrogen and oxygen. Kinetic studies establish that the chemicurrent is proportional to turnover frequency for temperatures ranging from 298 to 373 K for P{sub H2} between 1 and 8 Torr and P{sub O2} at 760 Torr. Both chemicurrent and turnover frequency exhibit a first order dependence on P{sub H2}.
Date: July 20, 2009
Creator: Hervier, Antoine; Renzas, J. Russell; Park, Jeong Y. & Somorjai, Gabor A.
Object Type: Article
System: The UNT Digital Library
Advances in NLTE Modeling for Integrated Simulations (open access)

Advances in NLTE Modeling for Integrated Simulations

The last few years have seen significant progress in constructing the atomic models required for non-local thermodynamic equilibrium (NLTE) simulations. Along with this has come an increased understanding of the requirements for accurately modeling the ionization balance, energy content and radiative properties of different elements for a wide range of densities and temperatures. Much of this progress is the result of a series of workshops dedicated to comparing the results from different codes and computational approaches applied to a series of test problems. The results of these workshops emphasized the importance of atomic model completeness, especially in doubly excited states and autoionization transitions, to calculating ionization balance, and the importance of accurate, detailed atomic data to producing reliable spectra. We describe a simple screened-hydrogenic model that calculates NLTE ionization balance with surprising accuracy, at a low enough computational cost for routine use in radiation-hydrodynamics codes. The model incorporates term splitting, {Delta}n = 0 transitions, and approximate UTA widths for spectral calculations, with results comparable to those of much more detailed codes. Simulations done with this model have been increasingly successful at matching experimental data for laser-driven systems and hohlraums. Accurate and efficient atomic models are just one requirement for integrated …
Date: July 8, 2009
Creator: Scott, H A & Hansen, S B
Object Type: Article
System: The UNT Digital Library
DEVELOPMENT AND VALIDATION OF A MULTIFIELD MODEL OF CHURN-TURBULENT GAS/LIQUID FLOWS (open access)

DEVELOPMENT AND VALIDATION OF A MULTIFIELD MODEL OF CHURN-TURBULENT GAS/LIQUID FLOWS

The accuracy of numerical predictions for gas/liquid two-phase flows using Computational Multiphase Fluid Dynamics (CMFD) methods strongly depends on the formulation of models governing the interaction between the continuous liquid field and bubbles of different sizes. The purpose of this paper is to develop, test and validate a multifield model of adiabatic gas/liquid flows at intermediate gas concentrations (e.g., churn-turbulent flow regime), in which multiple-size bubbles are divided into a specified number of groups, each representing a prescribed range of sizes. The proposed modeling concept uses transport equations for the continuous liquid field and for each bubble field. The overall model has been implemented in the NPHASE-CMFD computer code. The results of NPHASE-CMFD simulations have been validated against the experimental data from the TOPFLOW test facility. Also, a parametric analysis on the effect of various modeling assumptions has been performed.
Date: July 1, 2009
Creator: Tselishcheva, Elena A.; Antal, Steven P.; Podowski, Michael Z. & Guillen, Donna Post
Object Type: Article
System: The UNT Digital Library
Optimizing Low Temperature Diesel Combustion (LTC-D) "FreedomCAR and Vehicle Technologies Program Solicitation for University Research and Graduate Automotice Technology Education (GATE) Centers of Excellence" (open access)

Optimizing Low Temperature Diesel Combustion (LTC-D) "FreedomCAR and Vehicle Technologies Program Solicitation for University Research and Graduate Automotice Technology Education (GATE) Centers of Excellence"

The engine industry is currently facing severe emissions mandates. Pollutant emissions from mobile sources are a major source of concern. For example, US EPA mandates require emissions of particulate and nitrogen oxides (NOx) from heavy-duty diesel engine exhaust to drop at least 90 percent between 1998 and 2010. Effective analysis of the combustion process is required to guide the selection of technologies for future development since exhaust after-treatment solutions are not currently available that can meet the required emission reduction goals. The goal of this project is to develop methods to optimize and control Low Temperature Combustion Diesel technologies (LTC-D) that offers the potential of nearly eliminating engine NOx and particulate emissions at reduced cost over traditional methods by controlling pollutant emissions in-cylinder. The work was divided into 5 Tasks, featuring experimental and modeling components: 1.) Fundamental understanding of LTC-D and advanced model development, 2.) Experimental investigation of LTC-D combustion control concepts, 3.) Application of detailed models for optimization of LTC-D combustion and emissions, 4.) Impact of heat transfer and spray impingement on LTC-D combustion, and 5.) Transient engine control with mixed-mode combustion. As described in the final report (December 2008), outcomes from the research included providing guidelines to the …
Date: July 31, 2009
Creator: Reitz, Rolf; Farrell, P.; Foster, D.; Ghandhi, J.; Rutland, C. & Sanders, S.
Object Type: Report
System: The UNT Digital Library
Nanoscale Reinforced, Polymer Derived Ceramic Matrix Coatings (open access)

Nanoscale Reinforced, Polymer Derived Ceramic Matrix Coatings

The goal of this project was to explore and develop a novel class of nanoscale reinforced ceramic coatings for high temperature (600-1000 C) corrosion protection of metallic components in a coal-fired environment. It was focused on developing coatings that are easy to process and low cost. The approach was to use high-yield preceramic polymers loaded with nano-size fillers. The complex interplay of the particles in the polymer, their role in controlling shrinkage and phase evolution during thermal treatment, resulting densification and microstructural evolution, mechanical properties and effectiveness as corrosion protection coatings were investigated. Fe-and Ni-based alloys currently used in coal-fired environments do not possess the requisite corrosion and oxidation resistance for next generation of advanced power systems. One example of this is the power plants that use ultra supercritical steam as the working fluid. The increase in thermal efficiency of the plant and decrease in pollutant emissions are only possible by changing the properties of steam from supercritical to ultra supercritical. However, the conditions, 650 C and 34.5 MPa, are too severe and result in higher rate of corrosion due to higher metal temperatures. Coating the metallic components with ceramics that are resistant to corrosion, oxidation and erosion, is an …
Date: July 31, 2009
Creator: Bordia, Rajendra
Object Type: Report
System: The UNT Digital Library
Handbook on dynamics of jointed structures. (open access)

Handbook on dynamics of jointed structures.

The problem of understanding and modeling the complicated physics underlying the action and response of the interfaces in typical structures under dynamic loading conditions has occupied researchers for many decades. This handbook presents an integrated approach to the goal of dynamic modeling of typical jointed structures, beginning with a mathematical assessment of experimental or simulation data, development of constitutive models to account for load histories to deformation, establishment of kinematic models coupling to the continuum models, and application of finite element analysis leading to dynamic structural simulation. In addition, formulations are discussed to mitigate the very short simulation time steps that appear to be required in numerical simulation for problems such as this. This handbook satisfies the commitment to DOE that Sandia will develop the technical content and write a Joints Handbook. The content will include: (1) Methods for characterizing the nonlinear stiffness and energy dissipation for typical joints used in mechanical systems and components. (2) The methodology will include practical guidance on experiments, and reduced order models that can be used to characterize joint behavior. (3) Examples for typical bolted and screw joints will be provided.
Date: July 1, 2009
Creator: Ames, Nicoli M.; Lauffer, James P.; Jew, Michael D.; Segalman, Daniel Joseph; Gregory, Danny Lynn; Starr, Michael James et al.
Object Type: Report
System: The UNT Digital Library
Optimization of a Two-Fluid Hydrodynamic Model of Churn-Turbulent Flow (open access)

Optimization of a Two-Fluid Hydrodynamic Model of Churn-Turbulent Flow

A hydrodynamic model of two-phase, churn-turbulent flows is being developed using the computational multiphase fluid dynamics (CMFD) code, NPHASE-CMFD. The numerical solutions obtained by this model are compared with experimental data obtained at the TOPFLOW facility of the Institute of Safety Research at the Forschungszentrum Dresden-Rossendorf. The TOPFLOW data is a high quality experimental database of upward, co-current air-water flows in a vertical pipe suitable for validation of computational fluid dynamics (CFD) codes. A five-field CMFD model was developed for the continuous liquid phase and four bubble size groups using mechanistic closure models for the ensemble-averaged Navier-Stokes equations. Mechanistic models for the drag and non-drag interfacial forces are implemented to include the governing physics to describe the hydrodynamic forces controlling the gas distribution. The closure models provide the functional form of the interfacial forces, with user defined coefficients to adjust the force magnitude. An optimization strategy was devised for these coefficients using commercial design optimization software. This paper demonstrates an approach to optimizing CMFD model parameters using a design optimization approach. Computed radial void fraction profiles predicted by the NPHASE-CMFD code are compared to experimental data for four bubble size groups.
Date: July 1, 2009
Creator: Guillen, Donna Post
Object Type: Article
System: The UNT Digital Library
Bottom hadrons from lattice QCD with domain wall and NRQCD fermions (open access)

Bottom hadrons from lattice QCD with domain wall and NRQCD fermions

Dynamical 2+1 flavor lattice QCD is used to calculate the masses of bottom hadrons, including B mesons, singly and doubly bottom baryons, and for the first time also the triply-bottom baryon Omega{sub bbb}. The domain wall action is used for the up-, down-, and strange quarks (both valence and sea), while the bottom quark is implemented with non-relativistic QCD. A calculation of the bottomonium spectrum is also presented.
Date: July 1, 2009
Creator: Stefan Meinel, William Detmold, C.-J. David Lin, Matthew Wingate
Object Type: Article
System: The UNT Digital Library
Experimental and Modeling Studies of the Characteristics of Liquid Biofuels for Enhanced Combustion (open access)

Experimental and Modeling Studies of the Characteristics of Liquid Biofuels for Enhanced Combustion

The objectives of this project have been to develop a comprehensive set of fundamental data regarding the combustion behavior of biodiesel fuels and appropriately associated model fuels that may represent biodiesels in automotive engineering simulation. Based on the fundamental study results, an auxiliary objective was to identify differentiating characteristics of molecular fuel components that can be used to explain different fuel behavior and that may ultimately be used in the planning and design of optimal fuel-production processes. The fuels studied in this project were BQ-9000 certified biodiesel fuels that are certified for use in automotive engine applications. Prior to this project, there were no systematic experimental flame data available for such fuels. One of the key goals has been to generate such data, and to use this data in developing and verifying effective kinetic models. The models have then been reduced through automated means to enable multi-dimensional simulation of the combustion characteristics of such fuels in reciprocating engines. Such reliable kinetics models, validated against fundamental data derived from laminar flames using idealized flow models, are key to the development and design of optimal engines, engine operation and fuels. The models provide direct information about the relative contribution of different molecular …
Date: July 1, 2009
Creator: Meeks, E.; Modak, A. U.; Naik, C.V.; Puduppakkam, K. V.; Westbrook, C.; Egolfopoulos, F. N. et al.
Object Type: Report
System: The UNT Digital Library