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Drain Tank Information for Developing Design Basis of the Preliminary Design (open access)

Drain Tank Information for Developing Design Basis of the Preliminary Design

Tokamak Cooling Water System (TCWS) drain tanks (DTs) serve two functions: normal operation and safety operation. Normal DTs are used for regular maintenance operations when draining is necessary. Safety DTs are used to receive the water leaked into the Vacuum Vessel (VV) after an in-vessel loss of cooling accident (LOCA) event. The preliminary design of the DTs shall be based on the information provided by this document. The capacity of the normal DTs is estimated based on the internal volume of in-vessel components [e.g., First Wall/Blanket (FW/BLK) and Divertor (DIV)], Neutral Beam Injector (NBI) components, and TCWS piping, heat exchangers, electric heaters, pump casing, pressurizers, and valves. Water volumes have been updated based on 2004 design information, changes adopted because of approved Project Change Requests (PCRs), and data verification by U.S. ITER. Two tanks will store water from normal draining operations of the FW/BLK and DIV Primary Heat Transfer Systems (PHTSs). One tank will store water from normal draining operations of the NBI PHTS. The capacity of the safety DTs is based on analysis of a design-basis accident:1 a large leak from in-vessel components. There are two safety DTs that will receive water from a VV LOCA event and drainage …
Date: January 1, 2011
Creator: Ferrada, Juan J
Object Type: Report
System: The UNT Digital Library
Effect of Coal Properties and Operation Conditions on Flow Behavior of Coal Slag in Entrained Flow Gasifiers: A Brief Review (open access)

Effect of Coal Properties and Operation Conditions on Flow Behavior of Coal Slag in Entrained Flow Gasifiers: A Brief Review

Integrated gasification combined cycle (IGCC) is a potentially promising clean technology with an inherent advantage of low emissions, since the process removes contaminants before combustion instead of from flue gas after combustion, as in a conventional coal steam plant. In addition, IGCC has potential for cost-effective carbon dioxide capture. Availability and high capital costs are the main challenges to making IGCC technology more competitive and fully commercial. Experiences from demonstrated IGCC plants show that, in the gasification system, low availability is largely due to slag buildup in the gasifier and fouling in the syngas cooler downstream of the gasification system. In the entrained flow gasifiers used in IGCC plants, the majority of mineral matter transforms to liquid slag on the wall of the gasifier and flows out the bottom. However, a small fraction of the mineral matter (as fly ash) is entrained with the raw syngas out of the gasifier to downstream processing. This molten/sticky fly ash could cause fouling of the syngas cooler. Therefore, it is preferable to minimize the quantity of fly ash and maximize slag. In addition, the hot raw syngas is cooled to convert any entrained molten fly slag to hardened solid fly ash prior to …
Date: January 1, 2011
Creator: Wang,Ping & Massoudi, Mehrdad
Object Type: Article
System: The UNT Digital Library
Effect of palladium dispersion on the capture of toxic components from fuel gas by palladium-alumina sorbents (open access)

Effect of palladium dispersion on the capture of toxic components from fuel gas by palladium-alumina sorbents

The dispersion and location of Pd in alumina-supported sorbents prepared by different methods was found to influence the performance of the sorbents in the removal of mercury, arsine, and hydrogen selenide from a simulated fuel gas. When Pd is well dispersed in the pores of the support, contact interaction with the support is maximized, Pd is less susceptible to poisoning by sulfur. and the sorbent has better long-term activity for adsorption of arsine and hydrogen selenide. but poorer adsorption capacity for Hg. As the contact interaction between Pd and the support is lessened the Pd becomes more susceptible to poisoning by sulfur. resulting in higher capacity for Hg, but poorer long-term performance for adsorption of arsenic and selenium.
Date: January 1, 2011
Creator: Baltrus, J. P.; Granite, E. J.; Rupp, E. C.; Stanko, D. C.; Howard, B. & Pennline, H. W.
Object Type: Article
System: The UNT Digital Library
EFFICIENT THEORETICAL SCREENING OF SOLID SORBENTS FOR CO2 CAPTURE APPLICATIONS (open access)

EFFICIENT THEORETICAL SCREENING OF SOLID SORBENTS FOR CO2 CAPTURE APPLICATIONS

Carbon dioxide is a major combustion product of coal, which once released into the air can contribute to global climate change. Current CO2 capture technologies for power generation processes including amine solvents and CaO-based sorbent materials require very energy intensive regeneration steps which result in significantly decreased efficiency. Hence, there is a critical need for new materials that can capture and release CO2 reversibly with acceptable energy costs if CO2 is to be captured and sequestered economically. Inorganic sorbents are one such class of materials which typically capture CO2 through the reversible formation of carbonates. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO2 sorbent candidates from the vast array of possible solid materials has been proposed and validated. The ab initio thermodynamic technique has the advantage of identifying thermodynamic properties of CO2 capture reactions without any experimental input beyond crystallographic structural information of the solid phases involved. For a given solid, the first step is to attempt to extract thermodynamic properties from thermodynamic databases and available literatures. If the thermodynamic properties of the compound of interest are unknown, an ab initio thermodynamic …
Date: January 1, 2011
Creator: Duan, Yuhua; Sorescu, Dan C & Luebke, David
Object Type: Article
System: The UNT Digital Library
The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III (open access)

The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III

The Sloan Digital Sky Survey (SDSS) started a new phase in August 2008, with new instrumentation and new surveys focused on Galactic structure and chemical evolution, measurements of the baryon oscillation feature in the clustering of galaxies and the quasar Ly{alpha} forest, and a radial velocity search for planets around {approx}8000 stars. This paper describes the first data release of SDSS-III (and the eighth counting from the beginning of the SDSS). The release includes 5-band imaging of roughly 5200 deg{sup 2} in the Southern Galactic Cap, bringing the total footprint of the SDSS imaging to 14,555 deg{sup 2}, or over a third of the Celestial Sphere. All the imaging data have been reprocessed with an improved sky-subtraction algorithm and a final, self-consistent recalibration and flat-field determination. This release also includes all data from the second phase of the Sloan Extension for Galactic Understanding and Evolution (SEGUE-2), consisting of spectroscopy of approximately 118,000 stars at both high and low Galactic latitudes. All the more than half a million stellar spectra obtained with the SDSS spectrograph have been reprocessed through an improved stellar parameters pipeline, which has better determination of metallicity for high metallicity stars.
Date: January 1, 2011
Creator: Aihara, Hiroaki; Prieto, Carlos Allende; An, Deokkeun; Anderson, Scott F.; Aubourg, Eric; Balbinot, Eduardo et al.
Object Type: Article
System: The UNT Digital Library
Energy and air quality implications of passive stack ventilation in residential buildings (open access)

Energy and air quality implications of passive stack ventilation in residential buildings

Ventilation requires energy to transport and condition the incoming air. The energy consumption for ventilation in residential buildings depends on the ventilation rate required to maintain an acceptable indoor air quality. Historically, U.S. residential buildings relied on natural infiltration to provide sufficient ventilation, but as homes get tighter, designed ventilation systems are more frequently required particularly for new energy efficient homes and retrofitted homes. ASHRAE Standard 62.2 is used to specify the minimum ventilation rate required in residential buildings and compliance is normally achieved with fully mechanical whole-house systems; however, alternative methods may be used to provide the required ventilation when their air quality equivalency has been proven. One appealing method is the use of passive stack ventilation systems. They have been used for centuries to ventilate buildings and are often used in ventilation regulations in other countries. Passive stacks are appealing because they require no fans or electrical supply (which could lead to lower cost) and do not require maintenance (thus being more robust and reliable). The downside to passive stacks is that there is little control of ventilation air flow rates because they rely on stack and wind effects that depend on local time-varying weather. In this study …
Date: January 1, 2011
Creator: Mortensen, Dorthe Kragsig; Walker, Iain S. & Sherman, Max
Object Type: Article
System: The UNT Digital Library
Energy Storage Annual Progress Report - In Situ Acoustic Emission and X-ray Diffraction of Lithium Ion Battery Materials (ORNL) (open access)

Energy Storage Annual Progress Report - In Situ Acoustic Emission and X-ray Diffraction of Lithium Ion Battery Materials (ORNL)

None
Date: January 1, 2011
Creator: Daniel, Claus & Rhodes, Kevin J
Object Type: Book
System: The UNT Digital Library
Energy Storage Annual Progress Report - Intercalation kinetics and ion mobility in electrode materials (ORNL) (open access)

Energy Storage Annual Progress Report - Intercalation kinetics and ion mobility in electrode materials (ORNL)

None
Date: January 1, 2011
Creator: Daniel, Claus & Kalnaus, Sergiy
Object Type: Book
System: The UNT Digital Library
Energy upgrade as regards quench performance (open access)

Energy upgrade as regards quench performance

Since the cross section for W production increases rapidly with energy, we consider the possibility of increasing the collision energy of polarized protons at RHIC. The limits of present hardware are examined with a particular emphasis on the quench training performance of magnets. Ignoring the limits of the DX magnets, the short-sample currents for the main arc (8 cm) dipoles could allow an increase of more than 30%, however we estimate 400 to 500 training quenches for the just 8 cm dipoles to reach this level. We propose that a 10% increase in energy might be achieved with the present hardware configuration. Raising the beam energy to 275 GeV ({radical}s = 550 GeV) should increase the W production rate by almost 50% from the 250 GeV level for the same optics with identical {beta}*'s at the collision points.
Date: January 1, 2011
Creator: MacKay, W. W. & Tepikian, S.
Object Type: Report
System: The UNT Digital Library
Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark Pair Production (open access)

Evidence for a Mass Dependent Forward-Backward Asymmetry in Top Quark Pair Production

We present a new measurement of the inclusive forward-backward t{bar t} production asymmetry and its rapidity and mass dependence. The measurements are performed with data corresponding to an integrated luminosity of 5.3 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV, recorded with the CDF II Detector at the Fermilab Tevatron. Significant inclusive asymmetries are observed in both the laboratory frame and the t{bar t} rest frame, and in both cases are found to be consistent with CP conservation under interchange of t and {bar t}. In the t{bar t} rest frame, the asymmetry is observed to increase with the t{bar t} rapidity difference, {Delta}y, and with the invariant mass M{sub t{bar t}} of the t{bar t} system. Fully corrected parton-level asymmetries are derived in two regions of each variable, and the asymmetry is found to be most significant at large {Delta}y and M{sub t{bar t}}. For M{sub t{bar t}} {ge} 450 GeV/c{sup 2}, the parton-level asymmetry in the t{bar t} rest frame is A{sup t{bar t}} = 0.475 {+-} 0.114 compared to a next-to-leading order QCD prediction of 0.088 {+-} 0.013.
Date: January 1, 2011
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Object Type: Article
System: The UNT Digital Library
Evidence for an anomalous like-sign dimuon charge asymmetry (open access)

Evidence for an anomalous like-sign dimuon charge asymmetry

We present a measurement of the like-sign dimuon asymmetry in semileptonic b-hadron decays, performed using 6.1 fb{sup -1} of p{bar p} collisions recorded with the D0 detector at a center-of-mass energy {radical}s = 1.96 TeV at the Fermilab Tevatron collider. This measured value is A{sub sl}{sup b} = [-0.957 {+-} 0.251 (stat) {+-} 0.146 (syst)] %, which disagrees with the Standard Model prediction at a statistical level of 3.2 {sigma}, and provides the first evidence of anomalous CP violation in the mixing of neutral B mesons.
Date: January 1, 2011
Creator: Williams, M.R.J.
Object Type: Article
System: The UNT Digital Library
Exploring a multi-resolution modeling approach within the shallow-water equations (open access)

Exploring a multi-resolution modeling approach within the shallow-water equations

The ability to solve the global shallow-water equations with a conforming, variable-resolution mesh is evaluated using standard shallow-water test cases. While the long-term motivation for this study is the creation of a global climate modeling framework capable of resolving different spatial and temporal scales in different regions, the process begins with an analysis of the shallow-water system in order to better understand the strengths and weaknesses of the approach developed herein. The multiresolution meshes are spherical centroidal Voronoi tessellations where a single, user-supplied density function determines the region(s) of fine- and coarsemesh resolution. The shallow-water system is explored with a suite of meshes ranging from quasi-uniform resolution meshes, where the grid spacing is globally uniform, to highly variable resolution meshes, where the grid spacing varies by a factor of 16 between the fine and coarse regions. The potential vorticity is found to be conserved to within machine precision and the total available energy is conserved to within a time-truncation error. This result holds for the full suite of meshes, ranging from quasi-uniform resolution and highly variable resolution meshes. Based on shallow-water test cases 2 and 5, the primary conclusion of this study is that solution error is controlled primarily by …
Date: January 1, 2011
Creator: Ringler, Todd; Jacobsen, Doug; Gunzburger, Max; Ju, Lili; Duda, Michael & Skamarock, William
Object Type: Article
System: The UNT Digital Library
FedEx Express Gasoline Hybrid Electric Delivery Truck Evaluation: 12-Month Report (open access)

FedEx Express Gasoline Hybrid Electric Delivery Truck Evaluation: 12-Month Report

This report summarizes the data obtained in a 12-month comparison of three gasoline hybrid electric delivery vehicles with three comparable diesel vehicles. The data show that there was no statistical difference between operating cost per mile of the two groups of vehicles. As expected, tailpipe emissions were considerably lower across all drive cycles for the gHEV than for the diesel vehicle.
Date: January 1, 2011
Creator: Barnitt, R.
Object Type: Report
System: The UNT Digital Library
Feedbacks from Focus Group Meeting on Training and Implementation of Building Energy Codes in China (open access)

Feedbacks from Focus Group Meeting on Training and Implementation of Building Energy Codes in China

A focus group meeting is a very effective quality research approach to collect information on a specific project. Through focus group meetings at both Changchun and Ningbo in August 2010, the project team gained a more complete understandings of key stakeholders (such as their education level), their training needs and expectations, key factors influencing their decision making, and incurred implementation difficulties. In addition, the meeting helped the project team (especially PNNL) improve its understanding of the implementation status of building energy codes in other regions (such as small cities and counties neighboring to urban areas, small townships and rural areas distant from urban areas). The collected feedbacks will serve as important input not only for better design of training materials and the development of an on-line training website, but also for development of follow-up projects to promote building energy codes in China.
Date: January 1, 2011
Creator: Shui, Bin; Lin , Haiyan; Song, Bo; Halverson, Mark A.; Evans, Meredydd & Zhu, Xiaojiao
Object Type: Report
System: The UNT Digital Library
FEM Analysis of Nb-Sn Rutherford-type Cables (open access)

FEM Analysis of Nb-Sn Rutherford-type Cables

An important part of superconducting accelerator magnet work is the conductor. To produce magnetic fields larger than 10 T, brittle conductors are typically used. For instance, for Nb{sub 3}Sn the original round wire, in the form of a composite of Copper, Niobium and Tin, is assembled into a so-called Rutherford-type cable, which is used to wind the magnet. The magnet is then subjected to a high temperature heat treatment to produce the chemical reactions that make the material superconducting. At this stage the superconductor is brittle and its superconducting properties sensitive to strain. This work is based on the development of a 2D finite element model, which simulates the mechanical behavior of Rutherford-type cable before heat treatment. The model was applied to a number of different cable architectures. To validate a critical criterion adopted into the single Nb-Sn wire analysis, the results of the model were compared with those measured experimentally on cable cross sections.
Date: January 1, 2011
Creator: Barzi, Emanuela; Gallo, Giuseppe; Neri, Paolo & /Fermilab
Object Type: Article
System: The UNT Digital Library
FEMP Technical Assistance to U.S. NORTHCOM (Fact Sheet) (open access)

FEMP Technical Assistance to U.S. NORTHCOM (Fact Sheet)

Fact sheet overview of FEMP technical assistance services provided to the U.S. NORTHCOM as part of the American Recovery and Reinvestment Act.
Date: January 1, 2011
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Final Long-Term Management and Storage of Elemental Mercury Environmental Impact Statement Summary and Guide for Stakeholders (open access)

Final Long-Term Management and Storage of Elemental Mercury Environmental Impact Statement Summary and Guide for Stakeholders

Pursuant to the Mercury Export Ban Act of 2008 (P.L. 110-414), DOE was directed to designate a facility or facilities for the long-term management and storage of elemental mercury generated within the United States. Therefore, DOE has analyzed the storage of up to 10,000 metric tons (11,000 tons) of elemental mercury in a facility(ies) constructed and operated in accordance with the Solid Waste Disposal Act, as amended by the Resource Conservation and Recovery Act (74 FR 31723). DOE prepared this Final Mercury Storage EIS in accordance with the National Environmental Policy Act of 1969 (NEPA), as amended (42 U.S.C. 4321 et seq.), the Council on Environmental Quality (CEQ) implementing regulations (40 CFR 1500–1508), and DOE’s NEPA implementing procedures (10 CFR 1021) to evaluate reasonable alternatives for a facility(ies) for the long-term management and storage of elemental mercury. This Final Mercury Storage EIS analyzes the potential environmental, human health, and socioeconomic impacts of elemental mercury storage at seven candidate locations: Grand Junction Disposal Site near Grand Junction, Colorado; Hanford Site near Richland, Washington; Hawthorne Army Depot near Hawthorne, Nevada; Idaho National Laboratory near Idaho Falls, Idaho; Kansas City Plant in Kansas City, Missouri; Savannah River Site near Aiken, South Carolina; and …
Date: January 1, 2011
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Final Long-Term Management and Storage of Elemental Mercury Environmental Impact Statement Volume 2 (open access)

Final Long-Term Management and Storage of Elemental Mercury Environmental Impact Statement Volume 2

Pursuant to the Mercury Export Ban Act of 2008 (P.L. 110-414), DOE was directed to designate a facility or facilities for the long-term management and storage of elemental mercury generated within the United States. Therefore, DOE has analyzed the storage of up to 10,000 metric tons (11,000 tons) of elemental mercury in a facility(ies) constructed and operated in accordance with the Solid Waste Disposal Act, as amended by the Resource Conservation and Recovery Act (74 FR 31723). DOE prepared this Final Mercury Storage EIS in accordance with the National Environmental Policy Act of 1969 (NEPA), as amended (42 U.S.C. 4321 et seq.), the Council on Environmental Quality (CEQ) implementing regulations (40 CFR 1500–1508), and DOE’s NEPA implementing procedures (10 CFR 1021) to evaluate reasonable alternatives for a facility(ies) for the long-term management and storage of elemental mercury. This Final Mercury Storage EIS analyzes the potential environmental, human health, and socioeconomic impacts of elemental mercury storage at seven candidate locations: Grand Junction Disposal Site near Grand Junction, Colorado; Hanford Site near Richland, Washington; Hawthorne Army Depot near Hawthorne, Nevada; Idaho National Laboratory near Idaho Falls, Idaho; Kansas City Plant in Kansas City, Missouri; Savannah River Site near Aiken, South Carolina; and …
Date: January 1, 2011
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Final Long-Term Management and Storage of Elemental Mercury Environmental Impact Statement Volume1 (open access)

Final Long-Term Management and Storage of Elemental Mercury Environmental Impact Statement Volume1

Pursuant to the Mercury Export Ban Act of 2008 (P.L. 110-414), DOE was directed to designate a facility or facilities for the long-term management and storage of elemental mercury generated within the United States. Therefore, DOE has analyzed the storage of up to 10,000 metric tons (11,000 tons) of elemental mercury in a facility(ies) constructed and operated in accordance with the Solid Waste Disposal Act, as amended by the Resource Conservation and Recovery Act (74 FR 31723).DOE prepared this Final Mercury Storage EIS in accordance with the National Environmental Policy Act of 1969 (NEPA), as amended (42 U.S.C. 4321 et seq.), the Council on Environmental Quality (CEQ) implementing regulations (40 CFR 1500–1508), and DOE’s NEPA implementing procedures (10 CFR 1021) to evaluate reasonable alternatives for a facility(ies) for the long-term management and storage of elemental mercury. This Final Mercury Storage EIS analyzes the potential environmental, human health, and socioeconomic impacts of elemental mercury storage at seven candidate locations:Grand Junction Disposal Site near Grand Junction, Colorado; Hanford Site near Richland, Washington; Hawthorne Army Depot near Hawthorne, Nevada; Idaho National Laboratory near Idaho Falls, Idaho;Kansas City Plant in Kansas City, Missouri; Savannah River Site near Aiken, South Carolina; and Waste Control Specialists, …
Date: January 1, 2011
Creator: unknown
Object Type: Report
System: The UNT Digital Library
FINAL REPORT on Experimental Validation of Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accidents (open access)

FINAL REPORT on Experimental Validation of Stratified Flow Phenomena, Graphite Oxidation, and Mitigation Strategies of Air Ingress Accidents

The U.S. Department of Energy is performing research and development that focuses on key phenomena that are important during challenging scenarios that may occur in the Next Generation Nuclear Plant (NGNP)/Generation IV very high temperature reactor (VHTR). Phenomena Identification and Ranking studies to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important. Consequently, the development of advanced air ingress-related models and verification & validation are of very high priority for the NGNP Project. Following a loss of coolant and system depressurization incident, air ingress will occur through the break, leading to oxidation of the in-core graphite structure and fuel. This study indicates that depending on the location and the size of the pipe break, the air ingress phenomena are different. In an effort to estimate the proper safety margin, experimental data and tools, including accurate multidimensional thermal-hydraulic and reactor physics models, a burn-off model, and a fracture model are required. It will also require effective strategies to mitigate the effects of oxidation, eventually. This 3-year project (FY 2008–FY 2010) is focused on various issues related to the VHTR air-ingress accident, including (a) analytical and experimental study of air ingress caused by …
Date: January 1, 2011
Creator: Oh, Chang H.; Kim, Eung S.; NO, Hee C. & Cho, Nam Z.
Object Type: Report
System: The UNT Digital Library
Force Field Parameter Estimation of Functional Perfluoropolyether Lubricants (open access)

Force Field Parameter Estimation of Functional Perfluoropolyether Lubricants

The head disk interface in a hard disk drive can be considered to be one of the hierarchical multiscale systems, which require the hybridization of multiscale modeling methods with coarse-graining procedure. However, the fundamental force field parameters are required to enable the coarse-graining procedure from atomistic/molecular scale to mesoscale models. In this paper, we investigate beyond molecular level and perform ab initio calculations to obtain the force field parameters. Intramolecular force field parameters for Zdol and Ztetraol were evaluated with truncated PFPE molecules to allow for feasible quantum calculations while still maintaining the characteristic chemical structure of the end groups. Using the harmonic approximation to the bond and angle potentials, the parameters were derived from the Hessian matrix, and the dihedral force constants are fit to the torsional energy profiles generated by a series of constrained molecular geometry optimization.
Date: January 1, 2011
Creator: Smith, Robert; Chung, P. S.; Steckel, Janice A.; Jhon, Myung S. & Biegler, Lorenz T.
Object Type: Article
System: The UNT Digital Library
Force Field Parameter Estimation of Functional Perfluoropolyether Lubricants (open access)

Force Field Parameter Estimation of Functional Perfluoropolyether Lubricants

The head disk interface in hard disk drive can be considered one of the hierarchical multiscale systems, which require the hybridization of multiscale modeling methods with coarse-graining procedure. However, the fundamental force field parameters are required to enable the coarse-graining procedure from atomistic/molecular scale to mesoscale models .In this paper, we investigate beyond molecular level and perform ab-initio calculations to obtain the force field parameters. Intramolecular force field parameters for the Zdol and Ztetraol were evaluated with truncated PFPE molecules to allow for feasible quantum calculations while still maintaining the characteristic chemical structure of the end groups. Using the harmonic approximation to the bond and angle potentials, the parameters were derived from the Hessian matrix, and the dihedral force constants are fit to the torsional energy profiles generated by a series of constrained molecular geometry optimization.
Date: January 1, 2011
Creator: Smith, R.; Chung, P. S.; Steckel, J.; Jhon, M. S. & Biegler, L. T.
Object Type: Article
System: The UNT Digital Library
Force Field Parameter Estimation of Functional Perfluoropolyether Lubricants (open access)

Force Field Parameter Estimation of Functional Perfluoropolyether Lubricants

The head disk interface in hard disk drive can be considered one of the hierarchical multiscale systems, which require the hybridization of multiscale modeling methods with coarse-graining procedure. However, the fundamental force field parameters are required to enable the coarse-graining procedure from atomistic/molecular scale to mesoscale models .In this paper, we investigate beyond molecular level and perform ab-initio calculations to obtain the force field parameters. Intramolecular force field parameters for the Zdol and Ztetraol were evaluated with truncated PFPE molecules to allow for feasible quantum calculations while still maintaining the characteristic chemical structure of the end groups. Using the harmonic approximation to the bond and angle potentials, the parameters were derived from the Hessian matrix, and the dihedral force constants are fit to the torsional energy profiles generated by a series of constrained molecular geometry optimization.
Date: January 1, 2011
Creator: Smith, R.; Chung, P. S.; Steckel, J. A.; Jhon, M. S. & Biegler, L. T.
Object Type: Article
System: The UNT Digital Library
FY 2007 LDRD Director's R&D Progress SummaryProposal Title: Developing a Science Base for Fuel Reprocessing Separations in the Global Nuclear Energy Program (open access)

FY 2007 LDRD Director's R&D Progress SummaryProposal Title: Developing a Science Base for Fuel Reprocessing Separations in the Global Nuclear Energy Program

This work is aimed at developing an experimentally validated computational capability for understanding the complex processes governing the performance of solvent extraction devices used for separations in nuclear fuel reprocessing. These applications pose a grand challenge due to the combination of complicating factors in a three-dimensional, turbulent, reactive, multicomponent, multiphase/interface fluid flow system. The currently limited process simulation and scale-up capabilities provides uncertainty in the ability to select and design the separations technology for the demonstration plan of the Global Nuclear Energy Partnership (GNEP) program. We anticipate the development of science-based models for technology development and design. This project will position ORNL to address the emerging opportunity by creating an expandable process model validated experimentally. This project has three major thrusts, namely, a prototype experimental station, a continuum modeling and simulation effort, and molecular modeling and kinetics support. Excellent progress has been made in corresponding activities in this first year in: (1) defining, assembling, and operating a relevant prototype system for model validation; (2) establishing a mathematical model for fluid flow and transport; (3) deploying sub-scale molecular modeling.
Date: January 1, 2011
Creator: de Almeida, Valmor F; Tsouris, Costas; Birdwell Jr, Joseph F; D'Azevedo, Ed F; Jubin, Robert Thomas; DePaoli, David W et al.
Object Type: Report
System: The UNT Digital Library