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Sample records for amber kinetics flywheel

  1. Amber Kinetics | Open Energy Information

    Open Energy Info (EERE)

    search Name: Amber Kinetics Product: Start-up company developing a novel flywheel energy storage system with the Lawrence Livermore National Laboratory. References: Amber...

  2. Microsoft Word - Amber Kinetics - Final Technical Report (30 Dec 2015).docx

    Office of Scientific and Technical Information (OSTI)

    Report (Final) Smart Grid Demonstration Program Contract ID: DE-OE0000232 Sub-Area: 2.5 Demonstration of Promising Energy Storage Technologies Project Type: Flywheel Energy Storage Demonstration Revision: V1.0 Company Name: Amber Kinetics, Inc. December 30, 2015 ACKNOWLEDGMENT: Amber Kinetics would like to acknowledge the people and agencies that made this development possible. At the U.S. Department of Energy, we would like to acknowledge Dr. Imre Gyuk and Ronald Staubly, whose support and

  3. AMBER

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AMBER AMBER Description AMBER (Assisted Model Building with Energy Refinement) is the collective name for a suite of programs designed to carry out molecular mechanical force field simulations, particularly on biomolecules. See Amber force fields, AMBER consists of about 50 programs. Two major ones are: sander: Simulated annealing with NMR-derived energy restraints pmemd: This is an extensively-modified version of sander, optimized for periodic, PME simulations, and for GB simulations. It is

  4. Flywheels

    SciTech Connect (OSTI)

    Bender, Donald Arthur

    2015-05-01

    In use since ancient times, the flywheel has smoothed the flow of energy in rotating machinery from small, hand held devices to the largest engines. Today, standalone flywheel systems are being developed to store electrical energy. These systems are deployed in applications as diverse as uninterruptible power supplies, gantry cranes, and large research facilities. This chapter presents the technical foundation of flywheel design, a comparison with other energy storage technologies, and a survey of applications where flywheel energy storage systems are currently in service.

  5. Flywheel energy storage workshop

    SciTech Connect (OSTI)

    O`Kain, D.; Carmack, J.

    1995-12-31

    Since the November 1993 Flywheel Workshop, there has been a major surge of interest in Flywheel Energy Storage. Numerous flywheel programs have been funded by the Advanced Research Projects Agency (ARPA), by the Department of Energy (DOE) through the Hybrid Vehicle Program, and by private investment. Several new prototype systems have been built and are being tested. The operational performance characteristics of flywheel energy storage are being recognized as attractive for a number of potential applications. Programs are underway to develop flywheels for cars, buses, boats, trains, satellites, and for electric utility applications such as power quality, uninterruptible power supplies, and load leveling. With the tremendous amount of flywheel activity during the last two years, this workshop should again provide an excellent opportunity for presentation of new information. This workshop is jointly sponsored by ARPA and DOE to provide a review of the status of current flywheel programs and to provide a forum for presentation of new flywheel technology. Technology areas of interest include flywheel applications, flywheel systems, design, materials, fabrication, assembly, safety & containment, ball bearings, magnetic bearings, motor/generators, power electronics, mounting systems, test procedures, and systems integration. Information from the workshop will help guide ARPA & DOE planning for future flywheel programs. This document is comprised of detailed viewgraphs.

  6. High speed flywheel

    DOE Patents [OSTI]

    McGrath, Stephen V.

    1991-01-01

    A flywheel for operation at high speeds utilizes two or more ringlike coments arranged in a spaced concentric relationship for rotation about an axis and an expansion device interposed between the components for accommodating radial growth of the components resulting from flywheel operation. The expansion device engages both of the ringlike components, and the structure of the expansion device ensures that it maintains its engagement with the components. In addition to its expansion-accommodating capacity, the expansion device also maintains flywheel stiffness during flywheel operation.

  7. RPM Flywheel Battery | Open Energy Information

    Open Energy Info (EERE)

    RPM Flywheel Battery Jump to: navigation, search Name: RPM Flywheel Battery Place: California Product: Start-up planning to develop, produce, and market flywheel batteries for...

  8. Lightweight flywheel containment

    DOE Patents [OSTI]

    Smith, James R.

    2001-01-01

    A lightweight flywheel containment composed of a combination of layers of various material which absorb the energy of a flywheel structural failure. The various layers of material act as a vacuum barrier, momentum spreader, energy absorber, and reaction plate. The flywheel containment structure has been experimentally demonstrated to contain carbon fiber fragments with a velocity of 1,000 m/s and has an aerial density of less than 6.5 g/square centimeters. The flywheel containment, may for example, be composed of an inner high toughness structural layer, and energy absorbing layer, and an outer support layer. Optionally, a layer of impedance matching material may be utilized intermediate the flywheel rotor and the inner high toughness layer.

  9. Lightweight flywheel containment

    DOE Patents [OSTI]

    Smith, James R.

    2004-06-29

    A lightweight flywheel containment composed of a combination of layers of various material which absorb the energy of a flywheel structural failure. The various layers of material act as a vacuum barrier, momentum spreader, energy absorber, and reaction plate. The flywheel containment structure has been experimentally demonstrated to contain carbon fiber fragments with a velocity of 1,000 m/s and has an aerial density of less than 6.5 g/square centimeters. The flywheel containment, may for example, be composed of an inner high toughness structural layer, and energy absorbing layer, and an outer support layer. Optionally, a layer of impedance matching material may be utilized intermediate the flywheel rotor and the inner high toughness layer.

  10. Women @ Energy: Amber Boehnlein

    Broader source: Energy.gov [DOE]

    "Seeds planted early and cultivated well tend to bear fruit. My grandparents lived next to Roger Bacon High School in St. Bernard, Ohio which led to an amusing case of hero worship. As a very young girl, I wanted to be a Franciscan friar and study nature using the scientific method, just like Roger Bacon!" Read more from Amber on her profile here.

  11. Reactor coolant pump flywheel

    DOE Patents [OSTI]

    Finegan, John Raymond; Kreke, Francis Joseph; Casamassa, John Joseph

    2013-11-26

    A flywheel for a pump, and in particular a flywheel having a number of high density segments for use in a nuclear reactor coolant pump. The flywheel includes an inner member and an outer member. A number of high density segments are provided between the inner and outer members. The high density segments may be formed from a tungsten based alloy. A preselected gap is provided between each of the number of high density segments. The gap accommodates thermal expansion of each of the number of segments and resists the hoop stress effect/keystoning of the segments.

  12. Separators for flywheel rotors

    DOE Patents [OSTI]

    Bender, D.A.; Kuklo, T.C.

    1998-07-07

    A separator forms a connection between the rotors of a concentric rotor assembly. This separator allows for the relatively free expansion of outer rotors away from inner rotors while providing a connection between the rotors that is strong enough to prevent disassembly. The rotor assembly includes at least two rotors referred to as inner and outer flywheel rings or rotors. This combination of inner flywheel ring, separator, and outer flywheel ring may be nested to include an arbitrary number of concentric rings. The separator may be a segmented or continuous ring that abuts the ends of the inner rotor and the inner bore of the outer rotor. It is supported against centrifugal loads by the outer rotor and is affixed to the outer rotor. The separator is allowed to slide with respect to the inner rotor. It is made of a material that has a modulus of elasticity that is lower than that of the rotors. 10 figs.

  13. Separators for flywheel rotors

    DOE Patents [OSTI]

    Bender, Donald A.; Kuklo, Thomas C.

    1998-01-01

    A separator forms a connection between the rotors of a concentric rotor assembly. This separator allows for the relatively free expansion of outer rotors away from inner rotors while providing a connection between the rotors that is strong enough to prevent disassembly. The rotor assembly includes at least two rotors referred to as inner and outer flywheel rings or rotors. This combination of inner flywheel ring, separator, and outer flywheel ring may be nested to include an arbitrary number of concentric rings. The separator may be a segmented or continuous ring that abuts the ends of the inner rotor and the inner bore of the outer rotor. It is supported against centrifugal loads by the outer rotor and is affixed to the outer rotor. The separator is allowed to slide with respect to the inner rotor. It is made of a material that has a modulus of elasticity that is lower than that of the rotors.

  14. AMBER User's Manual

    SciTech Connect (OSTI)

    Vay, J.L.; Fawley, W.

    2000-11-08

    AMBER is a Particle-In-Cell (PIC) code which models the evolution of a representative slice of a relativistic electron beam in a linear accelerator. The beam is modeled as a steady flow and therefore no electromagnetic waves: all the fields (external and self-fields) are electrostatic and magnetostatic fields (for a complete description, see chapter 5). The possible elements describing the accelerator lattice are solenoids, accelerating gaps, pipes and apertures. Several kinds of beam distribution can be loaded: KV, gaussian, semi-gaussian, etc. Alternatively, the user can reconstruct (or load) a distribution from the output of another codefile, for example, an interface generating the beam distribution from output produced from EGUN or LSP codes is available as an option. This documentation first describes in detail the input files needed to run AMBER and the procedure to start the executable. The possible data files and graphical output are explained in the two following chapters. The last chapter describes the physics model and numerical techniques used. An example of input files and the result obtained with these inputs are also given in the Appendix.

  15. Flywheel Energy Systems Inc | Open Energy Information

    Open Energy Info (EERE)

    K2H 8S1 Product: Focuses on design, fabrication, assembling and distributing flywheel energy storage systems and related components. References: Flywheel Energy Systems Inc1...

  16. Fiber composite flywheel rim

    DOE Patents [OSTI]

    Davis, Donald E.; Ingham, Kenneth T.

    1987-01-01

    A flywheel 2 comprising a hub 4 having at least one radially projecting disc 6, an annular rim 14 secured to said disc and providing a surface circumferential to said hub, a first plurality of resin-impregnated fibers 22 wound about said rim congruent to said surface, and a shell 26 enclosing said first plurality of fibers and formed by a second plurality of resin-impregnated fibers wound about said rim tangentially to said surface.

  17. Fiber composite flywheel rim

    DOE Patents [OSTI]

    Davis, D.E.; Ingham, K.T.

    1987-04-28

    A flywheel comprising a hub having at least one radially projecting disc, an annular rim secured to said disc and providing a surface circumferential to said hub, a first plurality of resin-impregnated fibers wound about said rim congruent to said surface, and a shell enclosing said first plurality of fibers and formed by a second plurality of resin-impregnated fibers wound about said rim tangentially to said surface. 2 figs.

  18. Rimmed and edge thickened Stodola shaped flywheel

    DOE Patents [OSTI]

    Kulkarni, S.V.; Stone, R.G.

    1983-10-11

    A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body composed of essentially planar isotropic high strength material. The flywheel body is enclosed by a rim of circumferentially wound fiber embedded in resin. The rim promotes flywheel safety and survivability. The flywheel has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability. 6 figs.

  19. Women @ Energy: Amber Hames | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Amber Hames Women @ Energy: Amber Hames November 20, 2015 - 10:06am Addthis Amber Hames is a graduate fellow at Argonne National Laboratory. She's from Homer Glen, Illinois, and attended Lewis University, earning a bachelor's degree in chemistry. She is working on a doctorate in chemistry. Amber Hames is a graduate fellow at Argonne National Laboratory. She's from Homer Glen, Illinois, and attended Lewis University, earning a bachelor's degree in chemistry. She is working on a doctorate in

  20. Improved flywheel materials : characterization of nanofiber modified flywheel test specimen.

    SciTech Connect (OSTI)

    Boyle, Timothy J.; Bell, Nelson Simmons; Ehlen, Mark Andrew; Anderson, Benjamin John; Miller, William Kenneth

    2013-09-01

    As alternative energy generating devices (i.e., solar, wind, etc) are added onto the electrical energy grid (AC grid), irregularities in the available electricity due to natural occurrences (i.e., clouds reducing solar input or wind burst increasing wind powered turbines) will be dramatically increased. Due to their almost instantaneous response, modern flywheel-based energy storage devices can act a mechanical mechanism to regulate the AC grid; however, improved spin speeds will be required to meet the necessary energy levels to balance thesegreen' energy variances. Focusing on composite flywheels, we have investigated methods for improving the spin speeds based on materials needs. The so-called composite flywheels are composed of carbon fiber (C-fiber), glass fiber, and aglue' (resin) to hold them together. For this effort, we have focused on the addition of fillers to the resin in order to improve its properties. Based on the high loads required for standard meso-sized fillers, this project investigated the utility of ceramic nanofillers since they can be added at very low load levels due to their high surface area. The impact that TiO2 nanowires had on the final strength of the flywheel material was determined by athree-point-bend' test. The results of the introduction of nanomaterials demonstrated an increase instrength' of the flywheel's C-fiber-resin moiety, with an upper limit of a 30% increase being reported. An analysis of the economic impact concerning the utilization of the nanowires was undertaken and after accounting for new-technology and additional production costs, return on improved-nanocomposite investment was approximated at 4-6% per year over the 20-year expected service life. Further, it was determined based on the 30% improvement in strength, this change may enable a 20-30% reduction in flywheel energy storage cost (%24/kW-h).

  1. Rimmed and edge thickened Stodola shaped flywheel

    DOE Patents [OSTI]

    Kulkarni, Satish V. (San Ramon, CA); Stone, Richard G. (Oakland, CA)

    1983-01-01

    A flywheel (10) is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel (10) has a body (15) composed of essentially planar isotropic high strength material. The flywheel (10) body (15) is enclosed by a rim (50) of circumferentially wound fiber (2) embedded in resin (3). The rim (50) promotes flywheel (10) safety and survivability. The flywheel (10) has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability.

  2. CX-012512: Categorical Exclusion Determination

    Broader source: Energy.gov [DOE]

    Amber Kinetics Flywheel Energy Storage Demonstration CX(s) Applied: B3.6Date: 41848 Location(s): CaliforniaOffices(s): National Energy Technology Laboratory

  3. CX-012519: Categorical Exclusion Determination

    Office of Energy Efficiency and Renewable Energy (EERE)

    Amber Kinetics Flywheel Energy Storage Demonstration CX(s) Applied: B3.6Date: 41848 Location(s): CaliforniaOffices(s): National Energy Technology Laboratory

  4. Flywheel energy storage system focus of display

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Flywheel Energy Storage System Focus of Display Demonstration to feature advanced, solar-powered replacement for batteries For more information contact: e:mail: Public Affairs Golden, Colo., March 20, 1997 -- Media are invited to visit the flywheel display. What: An outdoor display and demonstration of an environmentally-friendly, advanced electricity storage technology that can replace lead acid batteries. A flywheel is a rapidly-spinning cylinder or disc suspended in a vacuum-sealed container

  5. Flywheel energy storage advances using HTS bearings.

    SciTech Connect (OSTI)

    Mulcahy, T. M.

    1998-09-11

    High-Temperature-Superconducting (HT) bearings have the potential to reduce idling losses and make flywheel energy storage economical. Demonstration of large, high-speed flywheels is key to market penetration. Toward this goal, a flywheel system has been developed and tested with 5-kg to 15-kg disk-shaped rotors. Rlm speeds exceeded 400 mls and stored energies were >80 W-hr. Test implementation required technological advances in nearly all aspects of the flywheel system. Features and limitations of the design and tests are discussed, especially those related to achieving additional energy storage.

  6. Rimmed and edge thickened stodola shaped flywheel. [Patent application

    DOE Patents [OSTI]

    Kulkarni, S.V.; Stone, R.G.

    1980-09-24

    A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body composed of essentially planar isotropic high strength material. The flywheel body is enclosed by a rim of circumferentially wound fiber embedded in resin. The rim promotes flywheel safety and survivability. The flywheel has a truncated and edge thickened Stodola shape designed to optimize system mass and energy storage capability.

  7. Optimum rotationally symmetric shells for flywheel rotors

    DOE Patents [OSTI]

    Blake, Henry W.

    2000-01-01

    A flywheel rim support formed from two shell halves. Each of the shell halves has a disc connected to the central shaft. A first shell element connects to the disc at an interface. A second shell element connects to the first shell element. The second shell element has a plurality of meridional slits. A cylindrical shell element connects to the second shell element. The cylindrical shell element connects to the inner surface of the flywheel rim. A flywheel rim support having a disc connected an outer diameter of a shaft. Two optimally shaped shell elements connect to the optimally shaped disc at an interface. The interface defines a discontinuity in a meridional slope of said support. A cylindrical shell element connects to the two shell elements. The cylindrical shell element has an outer surface for connecting to the inner surface of the flywheel rim. A flywheel rim casing includes an annular shell connected to the central shaft. The annular shell connects to the flywheel rim. A composite shell surrounds the shaft, annular shell and flywheel rim.

  8. Canned pump having a high inertia flywheel

    DOE Patents [OSTI]

    Veronesi, Luciano; Raimondi, ALbert A.

    1989-01-01

    A canned pump is described which includes a motor, impeller, shaft, and high inertia flywheel mounted within a hermetically sealed casing. The flywheel comprises a heavy metal disk made preferably of a uranium alloy with a stainless steel shell sealably enclosing the heavy metal. The outside surfaces of the stainless steel comprise thrust runners and a journal for mating with, respectively, thrust bearing shoes and radial bearing segments. The bearings prevent vibration of the pump and, simultaneously, minimize power losses normally associated with the flywheel resulting from frictionally pumping surrounding fluid.

  9. Canned pump having a high inertia flywheel

    DOE Patents [OSTI]

    Veronesi, L.; Raimondi, A.A.

    1989-12-12

    A canned pump is described which includes a motor, impeller, shaft, and high inertia flywheel mounted within a hermetically sealed casing. The flywheel comprises a heavy metal disk made preferably of a uranium alloy with a stainless steel shell sealably enclosing the heavy metal. The outside surfaces of the stainless steel comprise thrust runners and a journal for mating with, respectively, thrust bearing shoes and radial bearing segments. The bearings prevent vibration of the pump and, simultaneously, minimize power losses normally associated with the flywheel resulting from frictionally pumping surrounding fluid. 5 figs.

  10. Layered flywheel with stress reducing construction

    DOE Patents [OSTI]

    Friedericy, Johan A.; Towgood, Dennis A.

    1984-11-13

    A flywheel having elastic spokes carrying an elastic rim; and a hub coupling the spokes to a shaft and deforming in response to centrifugal force to match the radial distortion of the spokes.

  11. Rimmed and edge thickened Stodola shaped flywheel (Patent) |...

    Office of Scientific and Technical Information (OSTI)

    Title: Rimmed and edge thickened Stodola shaped flywheel A flywheel (10) is described that is useful for energy storage in a hybrid vehicle automotive power system or in some ...

  12. Fact Sheet: Beacon Power 20 MW Flywheel Frequency Regulation...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    including batteries, flywheels, electrochemical capacitors, superconducting magnetic energy storage (SMES), power electronics, and control systems, visit the Energy Storage page. ...

  13. 'Recycling' Grid Energy with Flywheel Technology | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    'Recycling' Grid Energy with Flywheel Technology 'Recycling' Grid Energy with Flywheel Technology September 30, 2010 - 5:03pm Addthis Seven-foot tall cylinders equipped with flywheel technology (shown above) will make up Beacon Power’s energy storage plant in Stephentown, N.Y. The company received a $43 million loan guarantee from the Energy Department to build the plant. | Photo courtesy of Beacon Power Corporation Seven-foot tall cylinders equipped with flywheel technology (shown above)

  14. Flywheel Energy Storage technology workshop

    SciTech Connect (OSTI)

    O`Kain, D.; Howell, D.

    1993-12-31

    Advances in recent years of high strength/lightweight materials, high performance magnetic bearings, and power electronics technology has spurred a renewed interest by the transportation, utility, and manufacturing industries in Flywheel Energy Storage (FES) technologies. FES offers several advantages over conventional electro-chemical energy storage, such as high specific energy and specific power, fast charging time, long service life, high turnaround efficiency (energy out/energy in), and no hazardous/toxic materials or chemicals are involved. Potential applications of FES units include power supplies for hybrid and electric vehicles, electric vehicle charging stations, space systems, and pulsed power devices. Also, FES units can be used for utility load leveling, uninterruptable power supplies to protect electronic equipment and electrical machinery, and for intermittent wind or photovoltaic energy sources. The purpose of this workshop is to provide a forum to highlight technologies that offer a high potential to increase the performance of FES systems and to discuss potential solutions to overcome present FES application barriers. This document consists of viewgraphs from 27 presentations.

  15. REACTOR-FLASH BOILER-FLYWHEEL POWER PLANT

    DOE Patents [OSTI]

    Loeb, E.

    1961-01-17

    A power generator in the form of a flywheel with four reactors positioned about its rim is described. The reactors are so positioned that steam, produced in the reactor, exists tangentially to the flywheel, giving it a rotation. The reactors are incompletely moderated without water. The water enters the flywheel at its axis, under sufficient pressure to force it through the reactors, where it is converted to steam. The fuel consists of parallel twisted ribbons assembled to approximate a cylinder.

  16. Amber Kinetics, Inc. Smart Grid Demonstration Project | Open...

    Open Energy Info (EERE)

    Comments Cancel Submit Categories: Smart Grid Projects Smart Grid Projects in United States Smart Grid Demonstration Projects Smart Grid Projects - Energy Storage Demonstrations...

  17. Reluctance apparatus for flywheel energy storage

    DOE Patents [OSTI]

    Hull, John R.

    2000-01-01

    A motor generator for providing high efficiency, controlled voltage output or storage of energy in a flywheel system. A motor generator includes a stator of a soft ferromagnetic material, a motor coil and a generator coil, and a rotor has at least one embedded soft ferromagnetic piece. Control of voltage output is achieved by use of multiple stator pieces and multiple rotors with controllable gaps between the stator pieces and the soft ferromagnetic piece.

  18. Flywheel energy storage with superconductor magnetic bearings

    DOE Patents [OSTI]

    Weinberger, Bernard R.; Lynds, Jr., Lahmer; Hull, John R.

    1993-01-01

    A flywheel having superconductor bearings has a lower drag to lift ratio that translates to an improvement of a factor of ten in the rotational decay rate. The lower drag results from the lower dissipation of melt-processed YBCO, improved uniformity of the permanent magnet portion of the bearings, operation in a different range of vacuum pressure from that taught by the art, and greater separation distance from the rotating members of conductive materials.

  19. Concentric ring flywheel without expansion separators

    DOE Patents [OSTI]

    Kuklo, T.C.

    1999-08-24

    A concentric ring flywheel wherein the adjacent rings are configured to eliminate the need for differential expansion separators between the adjacent rings. This is accomplished by forming a circumferential step on an outer surface of an inner concentric ring and forming a matching circumferential step on the inner surface of an adjacent outer concentric ring. During operation the circumferential steps allow the rings to differentially expand due to the difference in the radius of the rings without the formation of gaps therebetween, thereby eliminating the need for expansion separators to take up the gaps formed by differential expansion. 3 figs.

  20. Concentric ring flywheel without expansion separators

    DOE Patents [OSTI]

    Kuklo, Thomas C.

    1999-01-01

    A concentric ring flywheel wherein the adjacent rings are configured to eliminate the need for differential expansion separators between the adjacent rings. This is accomplished by forming a circumferential step on an outer surface of an inner concentric ring and forming a matching circumferential step on the inner surface of an adjacent outer concentric ring. During operation the circumferential steps allow the rings to differentially expand due to the difference in the radius of the rings without the formation of gaps therebetween, thereby eliminating the need for expansion separators to take up the gaps formed by differential expansion.

  1. CX-000760: Categorical Exclusion Determination

    Office of Energy Efficiency and Renewable Energy (EERE)

    Amber Kinetics Flywheel Energy Storage DemonstrationCX(s) Applied: B3.6Date: 02/09/2010Location(s): Freemont, CaliforniaOffice(s): Electricity Delivery and Energy Reliability, National Energy Technology Laboratory

  2. Flywheel Energy Storage -- An Alternative to Batteries for UPS Systems

    SciTech Connect (OSTI)

    Brown, Daryl R.; Chvala, William D.

    2003-11-12

    Direct current (DC) system flywheel energy storage technology can be used as a substitute for batteries for providing backup power to an uninterruptible power supply (UPS) system. Although the initial cost will usually be higher, flywheels offer a much longer life, reduced maintenance, a smaller footprint, and better reliability compared to a battery. The combination of these characteristics will generally result in a lower life-cycle cost for a flywheel compared to a battery. This paper describes the technology, its variations, and installation requirements, as well as provides application advice. One Federal application is highlighted as a “case study,” followed by an illustrative life-cycle cost comparison of batteries and flywheels. A list of manufacturers, with contact information is also provided.

  3. Flywheel Project Escalates Grid Efficiency | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Flywheel Project Escalates Grid Efficiency Flywheel Project Escalates Grid Efficiency August 9, 2010 - 1:18pm Addthis Elizabeth Meckes Elizabeth Meckes Director of User Experience & Digital Technologies, Office of Public Affairs What does this project do? It's estimated to create 60 jobs in New York and Massachusetts (where Beacon Power is headquartered) and help bring clean technologies to market by improving the stability and reliability of the state's electric grid. More good news for New

  4. Flywheel Energy Storage Device for Hybrid and Electric Vehicles - Energy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Innovation Portal Energy Storage Energy Storage Find More Like This Return to Search Flywheel Energy Storage Device for Hybrid and Electric Vehicles Oak Ridge National Laboratory Contact ORNL About This Technology Technology Marketing SummaryThis cost-effective technology stores and reuses what would otherwise be wasted energy inside a hybrid electric vehicle engine. The invention, a mechanical flywheel coupled to a rotor inside the engine, stores rotational energy during engine performance,

  5. Interlayer toughening of fiber composite flywheel rotors

    DOE Patents [OSTI]

    Groves, Scott E.; Deteresa, Steven J.

    1998-01-01

    An interlayer toughening mechanism to mitigate the growth of damage in fiber composite flywheel rotors for long application. The interlayer toughening mechanism may comprise one or more tough layers composed of high-elongation fibers, high-strength fibers arranged in a woven pattern at a range from 0.degree. to 90.degree. to the rotor axis and bound by a ductile matrix material which adheres to and is compatible with the materials used for the bulk of the rotor. The number and spacing of the tough interlayers is a function of the design requirements and expected lifetime of the rotor. The mechanism has particular application in uninterruptable power supplies, electrical power grid reservoirs, and compulsators for electric guns, as well as electromechanical batteries for vehicles.

  6. Interlayer toughening of fiber composite flywheel rotors

    DOE Patents [OSTI]

    Groves, S.E.; Deteresa, S.J.

    1998-07-14

    An interlayer toughening mechanism is described to mitigate the growth of damage in fiber composite flywheel rotors for long application. The interlayer toughening mechanism may comprise one or more tough layers composed of high-elongation fibers, high-strength fibers arranged in a woven pattern at a range from 0{degree} to 90{degree} to the rotor axis and bound by a ductile matrix material which adheres to and is compatible with the materials used for the bulk of the rotor. The number and spacing of the tough interlayers is a function of the design requirements and expected lifetime of the rotor. The mechanism has particular application in uninterruptable power supplies, electrical power grid reservoirs, and compulsators for electric guns, as well as electromechanical batteries for vehicles. 2 figs.

  7. Amber Plug-In for Protein Shop () | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Software: Amber Plug-In for Protein Shop Citation Details Software Request Title: Amber Plug-In for Protein Shop The Amber Plug-in for ProteinShop has two main components: an AmberEngine library to compute the protein energy models, and a module to solve the energy minimization problem using an optimization algorithm in the OPTI-+ library. Together, these components allow the visualization of the protein folding process in ProteinShop. AmberEngine is a object-oriented library to compute

  8. Matched metal die compression molded structural random fiber sheet molding compound flywheel. [Patent application

    DOE Patents [OSTI]

    Kulkarni, S.V.; Christensen, R.M.; Toland, R.H.

    1980-09-24

    A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body of essentially planar isotropic high strength structural random fiber sheet molding compound (SMC-R). The flywheel may be economically produced by a matched metal die compression molding process. The flywheel makes energy intensive efficient use of a fiber/resin composite while having a shape designed by theory assuming planar isotropy.

  9. Matched metal die compression molded structural random fiber sheet molding compound flywheel

    DOE Patents [OSTI]

    Kulkarni, Satish V.; Christensen, Richard M.; Toland, Richard H.

    1985-01-01

    A flywheel (10) is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel (10) has a body of essentially planar isotropic high strength structural random fiber sheet molding compound (SMC-R). The flywheel (10) may be economically produced by a matched metal die compression molding process. The flywheel (10) makes energy intensive efficient use of a fiber/resin composite while having a shape designed by theory assuming planar isotropy.

  10. Evaluation of Demo 1C composite flywheel rotor burst test and containment design

    SciTech Connect (OSTI)

    Kass, M.D.; McKeever, J.W.; Akerman, M.A.; Goranson, P.L.; Litherland, P.S.; O`Kain, D.U.

    1998-07-01

    Laboratory-Directed funds were provided in FY 1995 for research to develop flywheel containment specifications and to consider concepts that could satisfy these specifications and produce a prototype small, lightweight, inexpensive, mobile flywheel containment. Research activities have included an analytical and pictorial review of the Demo 1C flywheel failure test, which provided significant insight about radial and axial failure modes; calculations of the thickness of ultra-conservative pressure vessel containment; entertainment of advanced containment concepts using lightweight materials and armor literature; consideration of fabrication assembly procedures; and participation in a Flywheel Energy Storage Workshop during which additional flywheel failure experiences were discussed. Based on these activities, calculations, and results, a list of conclusions concerning flywheel containment and its relation to the flywheel are presented followed by recommendations for further research.

  11. Dynamic voltage compensation on distribution feeders using flywheel energy storage

    SciTech Connect (OSTI)

    Weissbach, R.S.; Karady, G.G.; Farmer, R.G.

    1999-04-01

    Advancements in power electronics bearings and materials have made flywheel energy storage systems a viable alternative to electrochemical batteries. A future application of such a device is as an uninterruptible power supply for critical loads on a distribution feeder. However, the same power electronics and flywheel system could also be used for dynamic voltage compensation. A comparison is made between series and parallel connection of such dynamic compensation techniques used to maintain rated load voltage on distribution feeders when there are momentary dips in the supply voltage. For each case a mathematical model is presented and analyzed. The two cases are compared and the series compensation technique is more effective.

  12. The magnetic flywheel flow meter: Theoretical and experimental contributions

    SciTech Connect (OSTI)

    Buchenau, D. Galindo, V.; Eckert, S.

    2014-06-02

    The development of contactless flow meters is an important issue for monitoring and controlling of processes in different application fields, like metallurgy, liquid metal casting, or cooling systems for nuclear reactors and transmutation machines. Shercliff described in his book “The Theory of Electromagnetic Flow Measurement, Cambridge University Press, 1962” a simple and robust device for contact-less measurements of liquid metal flow rates which is known as magnetic flywheel. The sensor consists of several permanent magnets attached on a rotatable soft iron plate. This arrangement will be placed closely to the liquid metal flow to be measured, so that the field of the permanent magnets penetrates into the fluid volume. The flywheel will be accelerated by a Lorentz force arising from the interaction between the magnetic field and the moving liquid. Steady rotation rates of the flywheel can be taken as a measure for the mean flow rate inside the fluid channel. The present paper provides a detailed theoretical description of the sensor in order to gain a better insight into the functional principle of the magnetic flywheel. Theoretical predictions are confirmed by corresponding laboratory experiments. For that purpose, a laboratory model of such a flow meter was built and tested on a GaInSn-loop under various test conditions.

  13. Fact Sheet: Beacon Power 20 MW Flywheel Frequency Regulation Plant (August

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    2013) | Department of Energy Beacon Power 20 MW Flywheel Frequency Regulation Plant (August 2013) Fact Sheet: Beacon Power 20 MW Flywheel Frequency Regulation Plant (August 2013) Beacon Power will design, build, and operate a utility-scale 20 MW flywheel energy storage plant at the Humboldt Industrial Park in Hazle Township, PA for Hazle Spindle LLC. The plant will provide frequency regulation services to grid operator PJM Interconnection. For more information about how OE performs research

  14. Hazle Spindle, LLC Beacon Power 20 MW Flywheel Frequency Regulation Plant

    Energy Savers [EERE]

    Hazle Spindle, LLC Beacon Power 20 MW Flywheel Frequency Regulation Plant Project Description Beacon Power will design, build, and operate a utility-scale 20MW flywheel plant at the Humboldt Industrial Park in Hazle Township, Pennsylvania for the plant owner/operator, Hazle Spindle LLC The plant will provide frequency regulation services to grid operator PJM Interconnection. The Beacon Power technology uses flywheels to recycle energy from the grid in response to changes in demand and grid

  15. AN ASSESSMENT OF FLYWHEEL HIGH POWER ENERGY STORAGE TECHNOLOGY FOR HYBRID VEHICLES

    SciTech Connect (OSTI)

    Hansen, James Gerald

    2012-02-01

    An assessment has been conducted for the DOE Vehicle Technologies Program to determine the state of the art of advanced flywheel high power energy storage systems to meet hybrid vehicle needs for high power energy storage and energy/power management. Flywheel systems can be implemented with either an electrical or a mechanical powertrain. The assessment elaborates upon flywheel rotor design issues of stress, materials and aspect ratio. Twelve organizations that produce flywheel systems submitted specifications for flywheel energy storage systems to meet minimum energy and power requirements for both light-duty and heavy-duty hybrid applications of interest to DOE. The most extensive experience operating flywheel high power energy storage systems in heavy-duty and light-duty hybrid vehicles is in Europe. Recent advances in Europe in a number of vehicle racing venues and also in road car advanced evaluations are discussed. As a frame of reference, nominal weight and specific power for non-energy storage components of Toyota hybrid electric vehicles are summarized. The most effective utilization of flywheels is in providing high power while providing just enough energy storage to accomplish the power assist mission effectively. Flywheels are shown to meet or exceed the USABC power related goals (discharge power, regenerative power, specific power, power density, weight and volume) for HEV and EV batteries and ultracapacitors. The greatest technical challenge facing the developer of vehicular flywheel systems remains the issue of safety and containment. Flywheel safety issues must be addressed during the design and testing phases to ensure that production flywheel systems can be operated with adequately low risk.

  16. Interface structure for hub and mass attachment in flywheel rotors

    DOE Patents [OSTI]

    Deteresa, Steven J.; Groves, Scott E.

    1998-06-02

    An interface structure for hub and mass attachment in flywheel rotors. The interface structure efficiently transmits high radial compression forces and withstands both large circumferential elongation and local stresses generated by mass-loading and hub attachments. The interface structure is comprised of high-strength fiber, such as glass and carbon, woven into an angle pattern which is about 45.degree. with respect to the rotor axis. The woven fiber is bonded by a ductile matrix material which is compatible with and adheres to the rotor material. This woven fiber is able to elongate in the circumferential direction to match the rotor growth during spinning.

  17. Interface structure for hub and mass attachment in flywheel rotors

    DOE Patents [OSTI]

    Deteresa, S.J.; Groves, S.E.

    1998-06-02

    An interface structure is described for hub and mass attachment in flywheel rotors. The interface structure efficiently transmits high radial compression forces and withstands both large circumferential elongation and local stresses generated by mass-loading and hub attachments. The interface structure is comprised of high-strength fiber, such as glass and carbon, woven into an angle pattern which is about 45{degree} with respect to the rotor axis. The woven fiber is bonded by a ductile matrix material which is compatible with and adheres to the rotor material. This woven fiber is able to elongate in the circumferential direction to match the rotor growth during spinning. 2 figs.

  18. Investigation of Synergy Between Electrochemical Capacitors, Flywheels, and Batteries in Hybrid Energy Storage for PV Systems

    SciTech Connect (OSTI)

    Miller, John; Sibley, Lewis, B.; Wohlgemuth, John

    1999-06-01

    This report describes the results of a study that investigated the synergy between electrochemical capacitors (ECs) and flywheels, in combination with each other and with batteries, as energy storage subsystems in photovoltaic (PV) systems. EC and flywheel technologies are described and the potential advantages and disadvantages of each in PV energy storage subsystems are discussed. Seven applications for PV energy storage subsystems are described along with the potential market for each of these applications. A spreadsheet model, which used the net present value method, was used to analyze and compare the costs over time of various system configurations based on flywheel models. It appears that a synergistic relationship exists between ECS and flywheels. Further investigation is recommended to quantify the performance and economic tradeoffs of this synergy and its effect on overall system costs.

  19. Rimmed and edge thickened Stodola shaped flywheel (Patent) | SciTech

    Office of Scientific and Technical Information (OSTI)

    Connect Patent: Rimmed and edge thickened Stodola shaped flywheel Citation Details In-Document Search Title: Rimmed and edge thickened Stodola shaped flywheel × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information resources in energy science and technology. A paper copy of this document is also

  20. Model and simulation of a flywheel energy storage system at a utility substation using electro-magnetic transients programs

    SciTech Connect (OSTI)

    Weissbach, R.S.; Karady, G.G.; Farmer, R.G.

    1996-11-01

    A flywheel energy storage system for use as an uninterruptible power supply at a utility substation to replace electrochemical batteries has been modeled. The model is developed using the Electro-Magnetic Transients Program (EMTP). Models for the flywheel, permanent magnet (synchronous) motor/generator, rectifiers and inverter have been included. Transient response for loss of power and clearing of a short circuit fault, as well as variation of load voltage due to the flywheel spinning down, is presented.

  1. Amber Waves of...Switchgrass? How about Sorghum? | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Amber Waves of...Switchgrass? How about Sorghum? Amber Waves of...Switchgrass? How about Sorghum? October 28, 2011 - 5:09pm Addthis Matthew Loveless Matthew Loveless Data Integration Specialist, Office of Public Affairs What does this mean for me? For many counties, the expanding market for energy products made from biomass is a potential source of economic growth. Is your county one of them? As the fall harvest comes to an end in Marshall County, Kansas, farmers are already planning what crops

  2. THE WIDE-AREA ENERGY STORAGE AND MANAGEMENT SYSTEM PHASE II Final Report - Flywheel Field Tests

    SciTech Connect (OSTI)

    Lu, Ning; Makarov, Yuri V.; Weimar, Mark R.; Rudolph, Frank; Murthy, Shashikala; Arseneaux, Jim; Loutan, Clyde; Chowdhury, S.

    2010-08-31

    This research was conducted by Pacific Northwest National Laboratory (PNNL) operated for the U.S. department of Energy (DOE) by Battelle Memorial Institute for Bonneville Power Administration (BPA), California Institute for Energy and Environment (CIEE) and California Energy Commission (CEC). A wide-area energy management system (WAEMS) is a centralized control system that operates energy storage devices (ESDs) located in different places to provide energy and ancillary services that can be shared among balancing authorities (BAs). The goal of this research is to conduct flywheel field tests, investigate the technical characteristics and economics of combined hydro-flywheel regulation services that can be shared between Bonneville Power Administration (BPA) and California Independent System Operator (CAISO) controlled areas. This report is the second interim technical report for Phase II of the WAEMS project. This report presents: 1) the methodology of sharing regulation service between balancing authorities, 2) the algorithm to allocate the regulation signal between the flywheel and hydro power plant to minimize the wear-and-tear of the hydro power plants, 3) field results of the hydro-flywheel regulation service (conducted by the Beacon Power), and 4) the performance metrics and economic analysis of the combined hydro-flywheel regulation service.

  3. Utilization of rotor kinetic energy storage for hybrid vehicles

    DOE Patents [OSTI]

    Hsu, John S.

    2011-05-03

    A power system for a motor vehicle having an internal combustion engine, the power system comprises an electric machine (12) further comprising a first excitation source (47), a permanent magnet rotor (28) and a magnetic coupling rotor (26) spaced from the permanent magnet rotor and at least one second excitation source (43), the magnetic coupling rotor (26) also including a flywheel having an inertial mass to store kinetic energy during an initial acceleration to an operating speed; and wherein the first excitation source is electrically connected to the second excitation source for power cycling such that the flywheel rotor (26) exerts torque on the permanent magnet rotor (28) to assist braking and acceleration of the permanent magnet rotor (28) and consequently, the vehicle. An axial gap machine and a radial gap machine are disclosed and methods of the invention are also disclosed.

  4. Amber light-emitting diode comprising a group III-nitride nanowire active region

    DOE Patents [OSTI]

    Wang, George T.; Li, Qiming; Wierer, Jr., Jonathan J.; Koleske, Daniel

    2014-07-22

    A temperature stable (color and efficiency) III-nitride based amber (585 nm) light-emitting diode is based on a novel hybrid nanowire-planar structure. The arrays of GaN nanowires enable radial InGaN/GaN quantum well LED structures with high indium content and high material quality. The high efficiency and temperature stable direct yellow and red phosphor-free emitters enable high efficiency white LEDs based on the RGYB color-mixing approach.

  5. Sub-Area. 2.5 Demonstration of Promising Energy Storage Technologies

    Office of Scientific and Technical Information (OSTI)

    Project Type. Flywheel Energy Storage Demonstration Revision: V1.0 (Technical Report) | SciTech Connect Sub-Area. 2.5 Demonstration of Promising Energy Storage Technologies Project Type. Flywheel Energy Storage Demonstration Revision: V1.0 Citation Details In-Document Search Title: Sub-Area. 2.5 Demonstration of Promising Energy Storage Technologies Project Type. Flywheel Energy Storage Demonstration Revision: V1.0 In this program, Amber Kinetics designed, built, and tested a sub--scale 5

  6. Design guide for composite-material flywheels: rotor dyamic considerations. Part I. System whirling and stability. Final report

    SciTech Connect (OSTI)

    Bert, C.W.; Ramunujam, G.

    1981-09-01

    Information to designers of flywheels is provided which will enable them to predict many aspects of the dynamic behavior of their flywheel systems when spin-tested with a quill-shaft support and driven by an air turbine. Computer programs are presented for the following dynamic analysis to obtain the results indicated: free whirling for natural frequencies versus rotational speed and the associated mode shapes; rough-type stability analysis for determining the stability limits; and forced whirling analysis for estimating the response of major components of the system to flywheel mass eccentricity and initial tilt. For the first and third kinds of analyses, two different mathematical models of the generic system are investigated. One is a seven-degree-of-freedom lumped-parameter analysis, while the other is a combined distributed- and lumped-parameter analysis. When applied to an existing flywheel system, the two models yielded numerical values for the lowest first-order forward critical speed in very close agreement with each other and with experimental results obtained in spin tests. Therefore, for the second kind of analysis, only the lumped-parameter model is implemented. Qualitative discussions as to why forced retrograde whirling is not as severe as forward whirling are also presented. The analyses are applied to the multi-material ring type flywheel systems, a constant-thickness-diskring type, and a tapered-thickness-disk type. In addition, the effects of the following flywheel design parameters on system dynamics were investigated: flywheel mass; diametral and polar mass moments of inertia; location of mass center from the lower end of the quill shaft; quill shaft length; lower turbine-bearing support stiffness; equivalent viscous damping coefficient of the external damper; flywheel dead weight; and torque applied at the turbine.

  7. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    DOE Patents [OSTI]

    Kuklo, Thomas C. (Oakdale, CA)

    1999-01-01

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings.

  8. Concentric ring flywheel with hooked ring carbon fiber separator/torque coupler

    DOE Patents [OSTI]

    Kuklo, T.C.

    1999-07-20

    A concentric ring flywheel with expandable separators, which function as torque couplers, between the rings to take up the gap formed between adjacent rings due to differential expansion between different radius rings during rotation of the flywheel. The expandable separators or torque couplers include a hook-like section at an upper end which is positioned over an inner ring and a shelf-like or flange section at a lower end onto which the next adjacent outer ring is positioned. As the concentric rings are rotated the gap formed by the differential expansion there between is partially taken up by the expandable separators or torque couplers to maintain torque and centering attachment of the concentric rings. 2 figs.

  9. Inverse Kinetics

    Energy Science and Technology Software Center (OSTI)

    2000-03-20

    Given the space-independent, one energy group reactor kinetics equations and the initial conditions, this prgram determines the time variation of reactivity required to produce the given input of flux-time data.

  10. Development of long life three phase uninterruptible power supply using flywheel energy storage unit

    SciTech Connect (OSTI)

    Takahashi, Isao; Okita, Yoshihisa; Andoh, Itaru

    1995-12-31

    According to development of computer applications, uninterruptible power supplies (UPS) are indispensable to the industrial field. But the cost for maintaining the conventional UPS is very high, because frequent replacement of parts which have short life time is necessary. This paper describes the research and development of a new UPS which has long life parts for maintenance free. To lengthen the life time, the following techniques are introduced: (1) a flywheel energy storage unit having more than 20 years life time; (2) electrolytic capacitor less inverter and converter. By using these techniques, a three phase UPS rating 5kVA, 200V is developed, and excellent performance is obtained: input power factor is over 99.7%; output voltage distortion is under 1.5%; transformer less UPS achieves light weight system; the UPS have function of automatic output voltage balance using auxiliary diode rectifier; input current harmonic distortion is less than 1.2%, even if the single phase load is connected.

  11. Phase 1 STTR flywheel motor/alternator for hybrid electric vehicles. CRADA final report

    SciTech Connect (OSTI)

    McKeever, J.W.; Scudiere, M.B.; Ott, G.W. Jr.; White, C.P.; Kessinger, R.L. Jr.; Robinson, S.T.; Seymour, K.P.; Dockstadter, K.D.

    1997-12-31

    Visual Computing Systems (VCS) and the Oak Ridge National Laboratory (ORNL) have teamed, through a Phase 1 Small Business Technology Transfer (STTR) grant from the US Department of Energy (DOE), to develop an advanced, low-cost motor/alternator drive system suitable for Flywheel Energy Storage (FES) applications. During Phase 1, system performance and design requirements were established, design concepts were generated, and preliminary motor/alternator designs were developed and analyzed. ORNL provided mechanical design and finite element collaboration and Lynx Motion Technology, a spin-off from VCS to commercialize their technology, constructed a proof-of-concept axial-gap permanent magnet motor/alternator that employed their Segmented Electromagnetic Array (SEMA) with a survivable design speed potential of 10,000 rpm. The VCS motor/alternator was successfully tested in ORNL`s Motor Test Tank using an ORNL inverter and ORNL control electronics. It was first operated as an unloaded motor to 6,000 rpm and driven as an unloaded generator to 6,000 rpm. Output from the generator was then connected to a resistance bank, which caused the loaded generator to decelerate to 3,860 rpm where data was collected. After about 4-1/2 minutes, the test was terminated because of an impact noise. Subsequent inspection and operation at low speeds did not reveal the source of the noise. Electrical performance of the motor was excellent, encouraging continued development of this technology. Phase 2 efforts will focus on further design development and optimization, manufacturing development and prototype construction, testing, and evaluation.

  12. Design & development fo a 20-MW flywheel-based frequency regulation power plant : a study for the DOE Energy Storage Systems program.

    SciTech Connect (OSTI)

    Rounds, Robert; Peek, Georgianne Huff

    2009-01-01

    This report describes the successful efforts of Beacon Power to design and develop a 20-MW frequency regulation power plant based solely on flywheels. Beacon's Smart Matrix (Flywheel) Systems regulation power plant, unlike coal or natural gas generators, will not burn fossil fuel or directly produce particulates or other air emissions and will have the ability to ramp up or down in a matter of seconds. The report describes how data from the scaled Beacon system, deployed in California and New York, proved that the flywheel-based systems provided faster responding regulation services in terms of cost-performance and environmental impact. Included in the report is a description of Beacon's design package for a generic, multi-MW flywheel-based regulation power plant that allows accurate bids from a design/build contractor and Beacon's recommendations for site requirements that would ensure the fastest possible construction. The paper concludes with a statement about Beacon's plans for a lower cost, modular-style substation based on the 20-MW design.

  13. Combustion Kinetics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Kinetics - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Fuel Cycle Defense Waste Management Programs Advanced Nuclear Energy

  14. Strain-compensated (Ga,In)N/(Al,Ga)N/GaN multiple quantum wells for improved yellow/amber light emission

    SciTech Connect (OSTI)

    Lekhal, K.; Damilano, B. De Mierry, P.; Venngus, P.; Ngo, H. T.; Rosales, D.; Gil, B.; Hussain, S.

    2015-04-06

    Yellow/amber (570600?nm) emitting In{sub x}Ga{sub 1?x}N/Al{sub y}Ga{sub 1?y}N/GaN multiple quantum wells (QWs) have been grown by metal organic chemical vapor deposition on GaN-on- sapphire templates. When the (Al,Ga)N thickness of the barrier increases, the room temperature photoluminescence is red-shifted while its yield increases. This is attributed to an increase of the QW internal electric field and an improvement of the material quality due to the compensation of the compressive strain of the In{sub x}Ga{sub 1?x}N QWs by the Al{sub y}Ga{sub 1?y}N layers, respectively.

  15. Eco Kinetics | Open Energy Information

    Open Energy Info (EERE)

    Kinetics Jump to: navigation, search Name: eco-Kinetics Place: Stapylton, Queensland, Australia Zip: 4207 Sector: Renewable Energy Product: Queensland-based renewable energy...

  16. Chemical Kinetics of Combustion Processes

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Combustion (work-in-progress) * Chemical kinetic submodel of iso-butanol ... oxidation of isobutane and isobutene. * Chemical kinetic submodel of iso-butanol ...

  17. Erbium hydride decomposition kinetics.

    SciTech Connect (OSTI)

    Ferrizz, Robert Matthew

    2006-11-01

    Thermal desorption spectroscopy (TDS) is used to study the decomposition kinetics of erbium hydride thin films. The TDS results presented in this report are analyzed quantitatively using Redhead's method to yield kinetic parameters (E{sub A} {approx} 54.2 kcal/mol), which are then utilized to predict hydrogen outgassing in vacuum for a variety of thermal treatments. Interestingly, it was found that the activation energy for desorption can vary by more than 7 kcal/mol (0.30 eV) for seemingly similar samples. In addition, small amounts of less-stable hydrogen were observed for all erbium dihydride films. A detailed explanation of several approaches for analyzing thermal desorption spectra to obtain kinetic information is included as an appendix.

  18. Paint decontamination kinetics

    SciTech Connect (OSTI)

    Thornton, E.W.

    1984-04-01

    Decontamination kinetics of a high-gloss polyurethane paint have been investigated using a novel flow cell experiment where the sample was counted in situ during decontamination. The /sup 134/Cs, /sup 137/Cs, and /sup 90/Y decontaminations follow a rate law that can be predicted theoretically for contaminant ion desorption from weakly heterogeneous random surface adsorption sites. Paint surfaces show the same decontamination kinetics after damage by abrasion or ultraviolet irradiation prior to contamination. The systems investigated exhibit Freundlich adsorption isotherm behavior during contamination; this is also characteristic of weakly heterogeneous random surfaces and is very commonly observed in ion adsorption studies at low concentrations.

  19. LLNL Chemical Kinetics Modeling Group

    SciTech Connect (OSTI)

    Pitz, W J; Westbrook, C K; Mehl, M; Herbinet, O; Curran, H J; Silke, E J

    2008-09-24

    The LLNL chemical kinetics modeling group has been responsible for much progress in the development of chemical kinetic models for practical fuels. The group began its work in the early 1970s, developing chemical kinetic models for methane, ethane, ethanol and halogenated inhibitors. Most recently, it has been developing chemical kinetic models for large n-alkanes, cycloalkanes, hexenes, and large methyl esters. These component models are needed to represent gasoline, diesel, jet, and oil-sand-derived fuels.

  20. CLEERS Coordination & Joint Development of Benchmark Kinetics...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    More Documents & Publications CLEERS Coordination & Joint Development of Benchmark Kinetics for LNT & SCR CLEERS Coordination & Development of Catalyst Process Kinetic...

  1. Multidimensional simulation and chemical kinetics development...

    Office of Environmental Management (EM)

    Multidimensional simulation and chemical kinetics development for high efficiency clean combustion engines Multidimensional simulation and chemical kinetics development for high ...

  2. Amber Passmore | Department of Energy

    Office of Environmental Management (EM)

    Biofuels Algal Biofuels Algae image The Bioenergy Technologies Office's (BETO's) Algae Program is carrying out a long-term applied research and development (R&D) strategy to increase the yields and lower the costs of algal biofuels by working with partners to develop new technologies, to integrate technologies at commercially-relevant scales, and conduct crosscutting analyses to understand the potential and challenges of an algal biofuel industry that is capable of annually producing

  3. Amber_HEP-NERSC.pptx

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    DOE HEP Program Perspective HEP/NERSC Workshop November 12, 2009 2 What is High Energy Physics? The High Energy Physics (HEP) program mission is to understand how the universe works at its most fundamental level. We do this by:  Discovering the most elementary constituents of matter and energy,  Probing the interactions between them,  And exploring the basic nature of space and time. 3 The Three Frontiers of HEP  At the Energy Frontier, powerful accelerators are used to create new

  4. Chemical kinetics modeling

    SciTech Connect (OSTI)

    Westbrook, C.K.; Pitz, W.J.

    1993-12-01

    This project emphasizes numerical modeling of chemical kinetics of combustion, including applications in both practical combustion systems and in controlled laboratory experiments. Elementary reaction rate parameters are combined into mechanisms which then describe the overall reaction of the fuels being studied. Detailed sensitivity analyses are used to identify those reaction rates and product species distributions to which the results are most sensitive and therefore warrant the greatest attention from other experimental and theoretical research programs. Experimental data from a variety of environments are combined together to validate the reaction mechanisms, including results from laminar flames, shock tubes, flow systems, detonations, and even internal combustion engines.

  5. Kinetics of coal pyrolysis

    SciTech Connect (OSTI)

    Seery, D.J.; Freihaut, J.D.; Proscia, W.M. ); Howard, J.B.; Peters, W.; Hsu, J.; Hajaligol, M.; Sarofim, A. ); Jenkins, R.; Mallin, J.; Espindola-Merin, B. ); Essenhigh, R.; Misra, M.K. )

    1989-07-01

    This report contains results of a coordinated, multi-laboratory investigation of coal devolatilization. Data is reported pertaining to the devolatilization for bituminous coals over three orders of magnitude in apparent heating rate (100 to 100,000 + {degree}C/sec), over two orders of magnitude in particle size (20 to 700 microns), final particle temperatures from 400 to 1600{degree}C, heat transfer modes ranging from convection to radiative, ambient pressure ranging from near vacuum to one atmosphere pressure. The heat transfer characteristics of the reactors are reported in detail. It is assumed the experimental results are to form the basis of a devolatilization data base. Empirical rate expressions are developed for each phase of devolatilization which, when coupled to an awareness of the heat transfer rate potential of a particular devolatilization reactor, indicate the kinetics emphasized by a particular system reactor plus coal sample. The analysis indicates the particular phase of devolatilization that will be emphasized by a particular reactor type and, thereby, the kinetic expressions appropriate to that devolatilization system. Engineering rate expressions are developed from the empirical rate expressions in the context of a fundamental understanding of coal devolatilization developed in the course of the investigation. 164 refs., 223 figs., 44 tabs.

  6. CLEERS Coordination & Joint Development of Benchmark Kinetics...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    of Catalyst Process Kinetic Data CLEERS Coordination & Joint Development of Benchmark Kinetics for LNT & SCR Functionality of Commercial NOx Storage-Reduction Catalysts...

  7. Chemical Kinetic Research on HCCI & Diesel Fuels

    Energy Savers [EERE]

    Laboratory Chemical Kinetic Research on HCCI & Diesel Fuels William J. Pitz (PI), Charles ... and emission formation processes * Chemical kinetic models are critical for improved ...

  8. Thermodynamic and kinetic characterization of hydroxyethylamine...

    Office of Scientific and Technical Information (OSTI)

    Thermodynamic and kinetic characterization of hydroxyethylamine -secretase-1 inhibitors Citation Details In-Document Search Title: Thermodynamic and kinetic characterization of ...

  9. On the relationships between Michaelis–Menten kinetics, reverse Michaelis–Menten kinetics, Equilibrium Chemistry Approximation kinetics and quadratic kinetics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tang, J. Y.

    2015-09-03

    The Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use which of the two are often ambiguous. Here I show that these two kinetics are special approximations to the Equilibrium Chemistry Approximation kinetics, which is the first order approximation to the quadratic kinetics that solves the equation of enzyme-substrate complex exactly for a single enzyme single substrate biogeochemical reaction with the law of mass action and the assumption of quasi-steady-state formore » the enzyme-substrate complex and that the product genesis from enzyme-substrate complex is much slower than the equilibration between enzyme-substrate complexes, substrates and enzymes. In particular, I showed that the derivation of the Michaelis–Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis–Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in the Equilibrium Chemistry Approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis–Menten kinetics was found to persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently over-predict the normalized sensitivity ∂ ln v / ∂ ln [ E ]T of v with respect the total enzyme concentration [ E ]T and persistently under-predict the normalized sensitivity ∂ ln v / ∂ ln [ S ]T of v with respect to the total substrate concentration [ S ]T. Meanwhile, the reverse Michaelis–Menten kinetics persistently under-predicts ∂ ln v / ∂ ln k2+ and ∂ ln v / ∂ ln [ E ]T, and persistently over-predicts ∂ ln v / ∂ ln k1+ and ∂ ln v / ∂ ln [ S ]T. In contrast, the Equilibrium Chemistry Approximation kinetics always gives consistent predictions of ∂ ln v / ∂ ln k2+, ∂ ln v / ∂ ln k1+, ∂ ln v / ∂ ln [ E ]T and ∂ ln v / ∂ ln [ S ]T. Since the Equilibrium Chemistry Approximation kinetics includes the advantages from both the Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics and it is applicable for almost the whole range of substrate and enzyme abundances, soil biogeochemical modelers therefore no longer need to choose when to use the Michaelis–Menten kinetics or the reverse Michaelis–Menten kinetics. I expect removing this choice ambiguity will make it easier to formulate more robust and consistent land biogeochemical models.« less

  10. Stochastic Parallel PARticle Kinetic Simulator

    Energy Science and Technology Software Center (OSTI)

    2008-07-01

    SPPARKS is a kinetic Monte Carlo simulator which implements kinetic and Metropolis Monte Carlo solvers in a general way so that they can be hooked to applications of various kinds. Specific applications are implemented in SPPARKS as physical models which generate events (e.g. a diffusive hop or chemical reaction) and execute them one-by-one. Applications can run in paralle so long as the simulation domain can be partitoned spatially so that multiple events can be invokedmore » simultaneously. SPPARKS is used to model various kinds of mesoscale materials science scenarios such as grain growth, surface deposition and growth, and reaction kinetics. It can also be used to develop new Monte Carlo models that hook to the existing solver and paralle infrastructure provided by the code.« less

  11. Chemical kinetics and combustion modeling

    SciTech Connect (OSTI)

    Miller, J.A.

    1993-12-01

    The goal of this program is to gain qualitative insight into how pollutants are formed in combustion systems and to develop quantitative mathematical models to predict their formation rates. The approach is an integrated one, combining low-pressure flame experiments, chemical kinetics modeling, theory, and kinetics experiments to gain as clear a picture as possible of the process in question. These efforts are focused on problems involved with the nitrogen chemistry of combustion systems and on the formation of soot and PAH in flames.

  12. Kinetics, Mechanics and Microstructure Changes in Storage Media...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Kinetics, Mechanics and Microstructure Changes in Storage Media Kinetics, Mechanics and Microstructure Changes in Storage Media Presentation on the Kinetics, Mechanics and ...

  13. AER NY Kinetics LLC | Open Energy Information

    Open Energy Info (EERE)

    AER NY Kinetics LLC Jump to: navigation, search Name: AER NY Kinetics LLC Address: PO Box 585 21 Entrance Avenue Place: Ogdensburg Zip: 13669 Region: United States Sector: Marine...

  14. On fast reactor kinetics studies

    SciTech Connect (OSTI)

    Seleznev, E. F.; Belov, A. A.; Matveenko, I. P.; Zhukov, A. M.; Raskach, K. F.

    2012-07-01

    The results and the program of fast reactor core time and space kinetics experiments performed and planned to be performed at the IPPE critical facility is presented. The TIMER code was taken as computation support of the experimental work, which allows transient equations to be solved in 3-D geometry with multi-group diffusion approximation. The number of delayed neutron groups varies from 6 to 8. The code implements the solution of both transient neutron transfer problems: a direct one, where neutron flux density and its derivatives, such as reactor power, etc, are determined at each time step, and an inverse one for the point kinetics equation form, where such a parameter as reactivity is determined with a well-known reactor power time variation function. (authors)

  15. Nonlinear theory of drift-cyclotron kinetics and the possible breakdown of gyro-kinetics

    SciTech Connect (OSTI)

    Waltz, R. E.; Deng Zhao

    2013-01-15

    A nonlinear theory of drift-cyclotron kinetics (termed cyclo-kinetics here) is formulated to test the breakdown of the gyro-kinetic approximations. Six dimensional cyclo-kinetics can be regarded as an extension of five dimensional gyro-kinetics to include high-frequency cyclotron waves, which can interrupt the low-frequency gyro-averaging in the (sixth velocity grid) gyro-phase angle. Nonlinear cyclo-kinetics has no limit on the amplitude of the perturbations. Formally, there is no gyro-averaging when all cyclotron (gyro-phase angle) harmonics of the perturbed distribution function (delta-f) are retained. Retaining only the (low frequency) zeroth cyclotron harmonic in cyclo-kinetics recovers both linear and nonlinear gyro-kinetics. Simple recipes are given for converting continuum nonlinear delta-f gyro-kinetic transport simulation codes to cyclo-kinetics codes by retaining (at least some) higher cyclotron harmonics.

  16. Theoretical Studies in Chemical Kinetics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Studies in Chemical Kinetics ^ ^ iCi| under AEC Contract A T (30-1)-3780 " ■ ' Annual Report (1970) Principal In-vestigator: Martin Karpins Institution: Harvard University The research performed under this contract can best be sunmarized under several headings. (a) Alkali-Halideg Alkali-Halide (MX^ M*X*) Exchange Reactions. This project is being continued. A careful study of certain parameters obtained from alkali-halide crystals and used in the first surface for the KCl, NaBr were not

  17. Electron kinetic effects on interferometry,

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    kinetic effects on interferometry, polarimetry and Thomson scattering measurements in burning plasmas (invited)a) V. V. Mirnov, D. L. Brower, D. J. Den Hartog, W. X. Ding, J. Duff, and E. Parke Citation: Review of Scientific Instruments 85, 11D302 (2014); doi: 10.1063/1.4891176 View online: http://dx.doi.org/10.1063/1.4891176 View Table of Contents: http://scitation.aip.org/content/aip/journal/rsi/85/11?ver=pdfcov Published by the AIP Publishing Articles you may be interested in First

  18. Kinetic Modeling of Microbiological Processes

    SciTech Connect (OSTI)

    Liu, Chongxuan; Fang, Yilin

    2012-09-17

    Kinetic description of microbiological processes is vital for the design and control of microbe-based biotechnologies such as waste water treatment, petroleum oil recovery, and contaminant attenuation and remediation. Various models have been proposed to describe microbiological processes. This editorial article discusses the advantages and limiation of these modeling approaches in cluding tranditional, Monod-type models and derivatives, and recently developed constraint-based approaches. The article also offers the future direction of modeling researches that best suit for petroleum and environmental biotechnologies.

  19. Combustion kinetics and reaction pathways

    SciTech Connect (OSTI)

    Klemm, R.B.; Sutherland, J.W.

    1993-12-01

    This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

  20. Thermodynamic and kinetic characterization of hydroxyethylamine

    Office of Scientific and Technical Information (OSTI)

    β-secretase-1 inhibitors (Journal Article) | SciTech Connect Thermodynamic and kinetic characterization of hydroxyethylamine β-secretase-1 inhibitors Citation Details In-Document Search Title: Thermodynamic and kinetic characterization of hydroxyethylamine β-secretase-1 inhibitors Highlights: *Kinetic and thermodynamic characterization of 10 hydroxyethylamine BACE-1 inhibitors. *Equilibrium binding of inhibitors was enthalpy driven for BACE-1. *Negative entropy of binding was observed

  1. Multiscale Mathematics For Plasma Kinetics Spanning Multiple...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Multiscale Mathematics For Plasma Kinetics Spanning Multiple Collisionality Regimes Citation Details In-Document Search Title: Multiscale Mathematics For Plasma ...

  2. CLEERS Coordination & Development of Catalyst Process Kinetic...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    & Joint Development of Benchmark Kinetics for LNT & SCR Measurement and Characterization of Lean NOx Adsorber Regeneration and Desulfation and Controlling NOx from Multi-mode

  3. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Kinetic Measurements of a Criegee Intermediate Print In the earth's troposphere, which blankets the planet surface where we live and breathe, dust particles, gas molecules,...

  4. Kinetic Wave Power | Open Energy Information

    Open Energy Info (EERE)

    Wave Power Jump to: navigation, search Name: Kinetic Wave Power Address: 2861 N Tupelo St Place: Midland Zip: 48642 Region: United States Sector: Marine and Hydrokinetic Phone...

  5. Chemical kinetics and oil shale process design

    SciTech Connect (OSTI)

    Burnham, A.K.

    1993-07-01

    Oil shale processes are reviewed with the goal of showing how chemical kinetics influences the design and operation of different processes for different types of oil shale. Reaction kinetics are presented for organic pyrolysis, carbon combustion, carbonate decomposition, and sulfur and nitrogen reactions.

  6. Kinetic advantage of controlled intermediate nuclear fusion

    SciTech Connect (OSTI)

    Guo Xiaoming

    2012-09-26

    The dominated process of controlled fusion is to let nuclei gain enough kinetic energy to overcome Coulomb barrier. As a result, a fusion scheme can consider two factors in its design: to increase kinetic energy of nuclei and to alter the Coulomb barrier. Cold Fusion and Hot fusion are all one-factor schemes while Intermediate Fusion is a twofactors scheme. This made CINF kinetically superior. Cold Fusion reduces deuteron-deuteron distance, addressing Coulomb barrier, and Hot Fusion heat up plasma into extreme high temperature, addressing kinetic energy. Without enough kinetic energy made Cold Fusion skeptical. Extreme high temperature made Hot Fusion very difficult to engineer. Because CIFN addresses both factors, CIFN is a more promising technique to be industrialized.

  7. Video:Ashley Anderson and Amber Stoesser

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Video: Watch the Open Data Google+ Hangout Video: Watch the Open Data Google+ Hangout February 21, 2013 - 5:10pm Addthis Did you miss our open data hangout? View it here. Matthew Loveless Matthew Loveless Data Integration Specialist, Office of Public Affairs Want more info? Check out these open data resources. Thank you to everyone who tuned in to our Google+ Hangout on the "Impact of Open Data." If you weren't able to attend, a recording of the discussion is available above. We hope

  8. Modeling of Reactor Kinetics and Dynamics

    SciTech Connect (OSTI)

    Matthew Johnson; Scott Lucas; Pavel Tsvetkov

    2010-09-01

    In order to model a full fuel cycle in a nuclear reactor, it is necessary to simulate the short time-scale kinetic behavior of the reactor as well as the long time-scale dynamics that occur with fuel burnup. The former is modeled using the point kinetics equations, while the latter is modeled by coupling fuel burnup equations with the kinetics equations. When the equations are solved simultaneously with a nonlinear equation solver, the end result is a code with the unique capability of modeling transients at any time during a fuel cycle.

  9. UNLOCKING TAX EQUITY INVESTMENT

    Broader source: Energy.gov [DOE]

    This presentation summarizes the information given by Amber Kinetics during the DOE SunShot Grand Challenge: Summit and Technology Forum, June 13-14, 2012.

  10. Microscale Electrode Design Using Coupled Kinetic, Thermal and...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling Microscale Electrode Design Using Coupled Kinetic, Thermal and Mechanical Modeling 2009 DOE ...

  11. Chemical Kinetic Research on HCCI & Diesel Fuels | Department...

    Office of Environmental Management (EM)

    More Documents & Publications Chemical Kinetics Research on HCCI and Diesel Fuels Chemical Kinetic Research on HCCI & Diesel Fuels Vehicle Technologies Office Merit Review 2014: ...

  12. Detailed chemical kinetic model for ethanol oxidation (Technical...

    Office of Scientific and Technical Information (OSTI)

    Detailed chemical kinetic model for ethanol oxidation Citation Details In-Document Search Title: Detailed chemical kinetic model for ethanol oxidation You are accessing a ...

  13. Chemical Kinetic Research on HCCI & Diesel Fuels | Department...

    Energy Savers [EERE]

    More Documents & Publications Chemical Kinetic Research on HCCI & Diesel Fuels Vehicle Technologies Office Merit Review 2014: Chemical Kinetic Models for Advanced Engine ...

  14. Large kinetic asymmetry in the metal-insulator transition nucleated...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Large kinetic asymmetry in the metal-insulator transition nucleated at localized and extended defects Citation Details In-Document Search Title: Large kinetic...

  15. Transport Phenomena and Interfacial Kinetics in Planar Microfluidic...

    Office of Scientific and Technical Information (OSTI)

    Transport Phenomena and Interfacial Kinetics in Planar Microfluidic Membraneless Fuel Cells Citation Details In-Document Search Title: Transport Phenomena and Interfacial Kinetics ...

  16. Renormalized linear kinetic theory as derived from quantum field...

    Office of Scientific and Technical Information (OSTI)

    Renormalized linear kinetic theory as derived from quantum field theory: A novel ... Citation Details In-Document Search Title: Renormalized linear kinetic theory as derived ...

  17. Mechanism and Kinetic Modeling of Hydrogenation in The Organic...

    Office of Scientific and Technical Information (OSTI)

    Mechanism and Kinetic Modeling of Hydrogenation in The Organic GetterPd CatalystActivated Carbon Systems Citation Details In-Document Search Title: Mechanism and Kinetic Modeling ...

  18. Kinetic studies of protein L aggregation and disaggregation ...

    Office of Scientific and Technical Information (OSTI)

    Kinetic studies of protein L aggregation and disaggregation Citation Details In-Document Search Title: Kinetic studies of protein L aggregation and disaggregation No abstract ...

  19. On the relationships between the Michaelis–Menten kinetics, reverse Michaelis–Menten kinetics, equilibrium chemistry approximation kinetics, and quadratic kinetics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tang, J. Y.

    2015-12-01

    The Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics are two popular mathematical formulations used in many land biogeochemical models to describe how microbes and plants would respond to changes in substrate abundance. However, the criteria of when to use either of the two are often ambiguous. Here I show that these two kinetics are special approximations to the equilibrium chemistry approximation (ECA) kinetics, which is the first-order approximation to the quadratic kinetics that solves the equation of an enzyme–substrate complex exactly for a single-enzyme and single-substrate biogeochemical reaction with the law of mass action and the assumption of a quasi-steadymore » state for the enzyme–substrate complex and that the product genesis from enzyme–substrate complex is much slower than the equilibration between enzyme–substrate complexes, substrates, and enzymes. In particular, I show that the derivation of the Michaelis–Menten kinetics does not consider the mass balance constraint of the substrate, and the reverse Michaelis–Menten kinetics does not consider the mass balance constraint of the enzyme, whereas both of these constraints are taken into account in deriving the equilibrium chemistry approximation kinetics. By benchmarking against predictions from the quadratic kinetics for a wide range of substrate and enzyme concentrations, the Michaelis–Menten kinetics was found to persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln k2+ of the reaction velocity v with respect to the maximum product genesis rate k2+, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln k1+ of v with respect to the intrinsic substrate affinity k1+, persistently overpredict the normalized sensitivity ∂ ln v / ∂ ln [E]T of v with respect the total enzyme concentration [E]T, and persistently underpredict the normalized sensitivity ∂ ln v / ∂ ln [S]T of v with respect to the total substrate concentration [S]T. Meanwhile, the reverse Michaelis–Menten kinetics persistently underpredicts ∂ ln v / ∂ ln k2+ and ∂ ln v / ∂ ln [E]T, and persistently overpredicts ∂ ln v / ∂ ln k1+ and ∂ ln v / ∂ ln [S]T. In contrast, the equilibrium chemistry approximation kinetics always gives consistent predictions of ∂ ln v / ∂ ln k2+, ∂ ln v / ∂ ln k1+, ∂ ln v / ∂ ln [E]T, and ∂ ln v / ∂ ln [S]T, indicating that ECA-based models will be more calibratable if the modeled processes do obey the law of mass action. Since the equilibrium chemistry approximation kinetics includes advantages from both the Michaelis–Menten kinetics and the reverse Michaelis–Menten kinetics and it is applicable for almost the whole range of substrate and enzyme abundances, land biogeochemical modelers therefore no longer need to choose when to use the Michaelis–Menten kinetics or the reverse Michaelis–Menten kinetics. I expect that removing this choice ambiguity will make it easier to formulate more robust and consistent land biogeochemical models.« less

  20. Kinetics of heavy oil/coal coprocessing

    SciTech Connect (OSTI)

    Szladow, A.J.; Chan, R.K. ); Foudu, S.; Kelly, J.F. )

    1988-06-01

    A number of studies have been reported on coprocessing of coal and oil sand bitumen, petroleum residues and distillate fractions in catalytic and non-catalytic processes. The studies described the effects of feedstock characteristics, process chemistry and operating variables on the product yield and distribution; however, very few kinetic data were reported in these investigations. This paper presents the kinetic data and modelling of the CANMET coal/heavy oil coprocessing process. CANMET has been conducting research and process development work on coprocessing of Canadian heavy oil/bitumen and coal since 1979 including studies of the kinetics and mechanisms of coprocessing. As a continuation of the program, CANMET and Lobbe Technologies undertook a project on mathematical modelling of coprocessing kinetics with emphasis on the development of reaction engineering models for improved process performance and operation.

  1. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Kinetic Measurements of a Criegee Intermediate Direct Kinetic Measurements of a Criegee Intermediate Print Wednesday, 25 January 2012 00:00 In the earth's troposphere, which blankets the planet surface where we live and breathe, dust particles, gas molecules, water vapor, and sunlight provide the ingredients for a multitude of chemical reactions that can generate effects ranging from clouds and smog to acid rain and climate change. In 1949, chemist Rudolf Criegee proposed a novel chemical

  2. Diffusion In Confinement: Kinetic Simulations of Self- andCollective...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Diffusion In Confinement: Kinetic Simulations of Self- and Collective-Diffusion Behavior of Adsorbed Gases...

  3. Chemical Kinetic Modeling of Advanced Transportation Fuels

    SciTech Connect (OSTI)

    PItz, W J; Westbrook, C K; Herbinet, O

    2009-01-20

    Development of detailed chemical kinetic models for advanced petroleum-based and nonpetroleum based fuels is a difficult challenge because of the hundreds to thousands of different components in these fuels and because some of these fuels contain components that have not been considered in the past. It is important to develop detailed chemical kinetic models for these fuels since the models can be put into engine simulation codes used for optimizing engine design for maximum efficiency and minimal pollutant emissions. For example, these chemistry-enabled engine codes can be used to optimize combustion chamber shape and fuel injection timing. They also allow insight into how the composition of advanced petroleum-based and non-petroleum based fuels affect engine performance characteristics. Additionally, chemical kinetic models can be used separately to interpret important in-cylinder experimental data and gain insight into advanced engine combustion processes such as HCCI and lean burn engines. The objectives are: (1) Develop detailed chemical kinetic reaction models for components of advanced petroleum-based and non-petroleum based fuels. These fuels models include components from vegetable-oil-derived biodiesel, oil-sand derived fuel, alcohol fuels and other advanced bio-based and alternative fuels. (2) Develop detailed chemical kinetic reaction models for mixtures of non-petroleum and petroleum-based components to represent real fuels and lead to efficient reduced combustion models needed for engine modeling codes. (3) Characterize the role of fuel composition on efficiency and pollutant emissions from practical automotive engines.

  4. Neptunium Binding Kinetics with Arsenazo(III)

    SciTech Connect (OSTI)

    Leigh R. Martin; Aaron T. Johnson; Stephen P. Mezyk

    2014-08-01

    This document has been prepared to meet FCR&D level 2 milestone M2FT-14IN0304021, Report on the results of actinide binding kinetics with aqueous phase complexants This work was carried out under the auspices of the Thermodynamics and Kinetics of Advanced Separations Systems FCR&D work package. The report details kinetics experiments that were performed to measure rates of aqueous phase complexation for pentavalent neptunium with the chromotropic dye Arsenazo III (AAIII). The studies performed were designed to determine how pH, ionic strength and AAIII concentration may affect the rate of the reaction. A brief comparison with hexavalent neptunium is also made. It was identified that as pH was increased the rate of reaction also increased, however increasing the ionic strength and concentration of AAIII had the opposite effect. Interestingly, the rate of reaction of Np(VI) with AAIII was found to be slower than that of the Np(V) reaction.

  5. Kinetic studies of elementary chemical reactions

    SciTech Connect (OSTI)

    Durant, J.L. Jr.

    1993-12-01

    This program concerning kinetic studies of elementary chemical reactions is presently focussed on understanding reactions of NH{sub x} species. To reach this goal, the author is pursuing experimental studies of reaction rate coefficients and product branching fractions as well as using electronic structure calculations to calculate transition state properties and reaction rate calculations to relate these properties to predicted kinetic behavior. The synergy existing between the experimental and theoretical studies allow one to gain a deeper insight into more complex elementary reactions.

  6. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    J.D. Savee, D.L. Osborn, S.S. Vasu, C.J. Percival, D.E. Shallcross, and C.A. Taatjes, "Direct Kinetic Measurements of Criegee Intermediate (CH2OO) Formed by Reaction of CH2I...

  7. Kinetics of heavy oil/coal coprocessing

    SciTech Connect (OSTI)

    Szladow, A.J.; Chan, R.K.; Fouda, S.; Kelly, J.F. )

    1988-01-01

    A number of studies have been reported on coprocessing of coal and oil sand bitumen, petroleum residues and distillate fractions in catalytic and non-catalytic processes. The studies described the effects of feedstock characteristics, process chemistry and operating variables on the product yield and distribution; however, very few kinetic data were reported in these investigations. This paper presents the kinetic data and modeling of the CANMET coal/heavy oil coprocessing process. A number of reaction networks were evaluated for CANMET coprocessing. The final choice of model was a parallel model with some sequential characteristics. The model explained 90.0 percent of the total variance, which was considered satisfactory in view of the difficulties of modeling preasphaltenes. The models which were evaluated showed that the kinetic approach successfully applied to coal liquefaction and heavy oil upgrading can be also applied to coprocessing. The coal conversion networks and heavy oil upgrading networks are interrelated via the forward reaction paths of preasphaltenes, asphaltenes, and THFI and via the reverse kinetic paths of an adduct formation between preasphaltenes and heavy oil.

  8. Reflected kinetics model for nuclear space reactor kinetics and control scoping calculations

    SciTech Connect (OSTI)

    Washington, K.E.

    1986-05-01

    The objective of this research is to develop a model that offers an alternative to the point kinetics (PK) modelling approach in the analysis of space reactor kinetics and control studies. Modelling effort will focus on the explicit treatment of control drums as reactivity input devices so that the transition to automatic control can be smoothly done. The proposed model is developed for the specific integration of automatic control and the solution of the servo mechanism problem. The integration of the kinetics model with an automatic controller will provide a useful tool for performing space reactor scoping studies for different designs and configurations. Such a tool should prove to be invaluable in the design phase of a space nuclear system from the point of view of kinetics and control limitations.

  9. Investigation of NO2 Oxidation Kinetics and Burning Mode for...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    NO2 Oxidation Kinetics and Burning Mode for Medium Duty Diesel Particulate: Contrasting O2 and NO2 Oxidation Investigation of NO2 Oxidation Kinetics and Burning Mode for Medium ...

  10. The LANL atomic kinetics modeling effort and its application...

    Office of Scientific and Technical Information (OSTI)

    An on-line version of the codes is available at http:aphysics2.lanl.govtempweb. ATOMIC kinetics modelling code uses the atomic data for LTE or NLTE population kinetics models ...

  11. Laboratory support for in situ gasification reaction kinetics...

    Office of Scientific and Technical Information (OSTI)

    ALUMINIUM COMPOUNDS; CARBONACEOUS MATERIALS; CHALCOGENIDES; DECOMPOSITION; ENERGY SOURCES; FOSSIL FUELS; FUELS; IN-SITU PROCESSING; KINETICS; OXIDES; OXYGEN COMPOUNDS; ...

  12. An overview of flywheel energy systems.

    SciTech Connect (OSTI)

    Wolsky, A. M.; Energy Systems

    2002-05-01

    Passive magnetic bearings incorporating permanent magnets and ReBaCuO, together with carbon fibre, offer the possibility of increasing the stored, volumetric energy density of FES and unprecedentedly low idling loss of FES. Its stored energy need only satisfy customers needs for the time it takes to bring on conventional 'back-up'. The FES itself must come up to power quickly enough to avoid any disruption in the customer's operation (e.g., continuous industrial processes involving fragile materials, for example paper forming). Such customers do not care about the price of electricity nearly as much as they care about not ruining their product, damaging their machines or having 'clean ups' that stop or slow output. Firms that engage in electronic commerce and/or telecommunications also value uninterruptible power. Another set of potential customers (construction, electric railroads) may wish to avoid fluctuations in their electrical supply or they may wish to avoid causing harm to others who may hold them liable for poor power quality. Finally, real time prices (e.g., every 15 s) and real time commands, disseminated via internet, and distributed storage might enable reduced system generation costs. Generators and FES makers would have to cooperate to make this feasible. Now, the central techno-economic challenge is to build a high-power, low-loss motor generator that reaches full power in a very short time.

  13. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Kinetic Measurements of a Criegee Intermediate Print In the earth's troposphere, which blankets the planet surface where we live and breathe, dust particles, gas molecules, water vapor, and sunlight provide the ingredients for a multitude of chemical reactions that can generate effects ranging from clouds and smog to acid rain and climate change. In 1949, chemist Rudolf Criegee proposed a novel chemical pathway for one such reaction, known as ozonolysis: the destruction of alkenes (a type

  14. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Kinetic Measurements of a Criegee Intermediate Print In the earth's troposphere, which blankets the planet surface where we live and breathe, dust particles, gas molecules, water vapor, and sunlight provide the ingredients for a multitude of chemical reactions that can generate effects ranging from clouds and smog to acid rain and climate change. In 1949, chemist Rudolf Criegee proposed a novel chemical pathway for one such reaction, known as ozonolysis: the destruction of alkenes (a type

  15. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Kinetic Measurements of a Criegee Intermediate Print In the earth's troposphere, which blankets the planet surface where we live and breathe, dust particles, gas molecules, water vapor, and sunlight provide the ingredients for a multitude of chemical reactions that can generate effects ranging from clouds and smog to acid rain and climate change. In 1949, chemist Rudolf Criegee proposed a novel chemical pathway for one such reaction, known as ozonolysis: the destruction of alkenes (a type

  16. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Kinetic Measurements of a Criegee Intermediate Print In the earth's troposphere, which blankets the planet surface where we live and breathe, dust particles, gas molecules, water vapor, and sunlight provide the ingredients for a multitude of chemical reactions that can generate effects ranging from clouds and smog to acid rain and climate change. In 1949, chemist Rudolf Criegee proposed a novel chemical pathway for one such reaction, known as ozonolysis: the destruction of alkenes (a type

  17. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Kinetic Measurements of a Criegee Intermediate Print In the earth's troposphere, which blankets the planet surface where we live and breathe, dust particles, gas molecules, water vapor, and sunlight provide the ingredients for a multitude of chemical reactions that can generate effects ranging from clouds and smog to acid rain and climate change. In 1949, chemist Rudolf Criegee proposed a novel chemical pathway for one such reaction, known as ozonolysis: the destruction of alkenes (a type

  18. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Kinetic Measurements of a Criegee Intermediate Print In the earth's troposphere, which blankets the planet surface where we live and breathe, dust particles, gas molecules, water vapor, and sunlight provide the ingredients for a multitude of chemical reactions that can generate effects ranging from clouds and smog to acid rain and climate change. In 1949, chemist Rudolf Criegee proposed a novel chemical pathway for one such reaction, known as ozonolysis: the destruction of alkenes (a type

  19. Direct Kinetic Measurements of a Criegee Intermediate

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Direct Kinetic Measurements of a Criegee Intermediate Print In the earth's troposphere, which blankets the planet surface where we live and breathe, dust particles, gas molecules, water vapor, and sunlight provide the ingredients for a multitude of chemical reactions that can generate effects ranging from clouds and smog to acid rain and climate change. In 1949, chemist Rudolf Criegee proposed a novel chemical pathway for one such reaction, known as ozonolysis: the destruction of alkenes (a type

  20. Detailed Chemical Kinetic Modeling of Cyclohexane Oxidation

    SciTech Connect (OSTI)

    Silke, E J; Pitz, W J; Westbrook, C K; Ribaucour, M

    2006-11-10

    A detailed chemical kinetic mechanism has been developed and used to study the oxidation of cyclohexane at both low and high temperatures. Reaction rate constant rules are developed for the low temperature combustion of cyclohexane. These rules can be used for in chemical kinetic mechanisms for other cycloalkanes. Since cyclohexane produces only one type of cyclohexyl radical, much of the low temperature chemistry of cyclohexane is described in terms of one potential energy diagram showing the reaction of cyclohexyl radical + O{sub 2} through five, six and seven membered ring transition states. The direct elimination of cyclohexene and HO{sub 2} from RO{sub 2} is included in the treatment using a modified rate constant of Cavallotti et al. Published and unpublished data from the Lille rapid compression machine, as well as jet-stirred reactor data are used to validate the mechanism. The effect of heat loss is included in the simulations, an improvement on previous studies on cyclohexane. Calculations indicated that the production of 1,2-epoxycyclohexane observed in the experiments can not be simulated based on the current understanding of low temperature chemistry. Possible 'alternative' H-atom isomerizations leading to different products from the parent O{sub 2}QOOH radical were included in the low temperature chemical kinetic mechanism and were found to play a significant role.

  1. Kinetics of coal combustion: Part 2, Mechanisms and kinetics of coal volatiles combustion

    SciTech Connect (OSTI)

    Essenhigh, R.H.; Bailey, E.G.; Shaw, D.W. )

    1988-12-01

    Values of global kinetic constants for the combustion of coal volatiles have been determined for the first time for volatiles from three coals (two bituminous coals and a Texas lignite). Global kinetic constants for methane and propane were also measured in the same apparatus to allow comparison with reference gases. Comparisons have also been made with values of global kinetics for pure hydrocarbons from a range of experiments as found in the literature. The volatiles were pyrolyzed from crushed coal drawn on weighed trays through a gas-fired muffle furnace, and they were burned at the top of a tube in an intense back-mix volume treated theoretically as a stirred reactor. Two types of experiment were carried out: partial combustion measurements near the stoichiometric for all coals from which the global kinetics were determined; and extinction limits for the Pittsburgh {number sign}8 coal volatiles to determine the extinction loop. The near stoichiometric generated kinetic data were used to predict the extinction limits with substantial agreement. Extinction loops for methane, propane and carbon monoxide were also measured for comparison.

  2. Pedestal Fueling Simulations with a Coupled Kinetic-kinetic Plasma-neutral Transport Code

    SciTech Connect (OSTI)

    D.P. Stotler, C.S. Chang, S.H. Ku, J. Lang and G.Y. Park

    2012-08-29

    A Monte Carlo neutral transport routine, based on DEGAS2, has been coupled to the guiding center ion-electron-neutral neoclassical PIC code XGC0 to provide a realistic treatment of neutral atoms and molecules in the tokamak edge plasma. The DEGAS2 routine allows detailed atomic physics and plasma-material interaction processes to be incorporated into these simulations. The spatial pro le of the neutral particle source used in the DEGAS2 routine is determined from the uxes of XGC0 ions to the material surfaces. The kinetic-kinetic plasma-neutral transport capability is demonstrated with example pedestal fueling simulations.

  3. Energy Conservation Tests of a Coupled Kinetic-kinetic Plasma-neutral Transport Code

    SciTech Connect (OSTI)

    Stotler, D. P.; Chang, C. S.; Ku, S. H.; Lang, J.; Park, G.

    2012-08-29

    A Monte Carlo neutral transport routine, based on DEGAS2, has been coupled to the guiding center ion-electron-neutral neoclassical PIC code XGC0 to provide a realistic treatment of neutral atoms and molecules in the tokamak edge plasma. The DEGAS2 routine allows detailed atomic physics and plasma-material interaction processes to be incorporated into these simulations. The spatial pro le of the neutral particle source used in the DEGAS2 routine is determined from the uxes of XGC0 ions to the material surfaces. The kinetic-kinetic plasma-neutral transport capability is demonstrated with example pedestal fueling simulations.

  4. The Hydriding Kinetics of Organic Hydrogen Getters

    SciTech Connect (OSTI)

    Powell, G. L.

    2002-02-11

    The aging of hermetically sealed systems is often accompanied by the gradual production of hydrogen gas that is a result of the decay of environmental gases and the degradation of organic materials. In particular, the oxygen, water, hydrogen ''equilibrium'' is affected by the removal of oxygen due the oxidation of metals and organic materials. This shift of the above ''equilibrium'' towards the formation of hydrogen gas, particularly in crevices, may eventually reach an explosive level of hydrogen gas or degrade metals by hydriding them. The latter process is generally delayed until the oxidizing species are significantly reduced. Organic hydrogen getters introduced by Allied Signal Aerospace Company, Kansas City Division have proven to be a very effective means of preventing hydrogen gas accumulation in sealed containers. These getters are relatively unaffected by air and environmental gases. They can be packaged in a variety of ways to fit particular needs such as porous pellets, fine or coarse [gravel] powder, or loaded into silicone rubber. The hydrogen gettering reactions are extremely irreversible since the hydrogen gas is converted into an organic hydrocarbon. These getters are based on the palladium-catalyzed hydrogenation of triple bonds to double and then single bonds in aromatic aryl compounds. DEB (1,4 bis (phenyl ethynyl) benzene) typically mixed with 25% by weight carbon with palladium (1% by weight of carbon) is one of the newest and best of these organic hydrogen getters. The reaction mechanisms are complex involving solid state reaction with a heterogeneous catalyst leading to the many intermediates, including mixed alkyl and aryl hydrocarbons with the possibilities of many isomers. The reaction kinetics mechanisms are also strongly influenced by the form in which they are packaged. For example, the hydriding rates for pellets and gravel have a strong dependence on reaction extent (i.e., DEB reduction) and a kinetic order in pressure of 0.76. Silicone rubber based DEB getters hydride at a much lower rate, have little dependence on reaction extent, have a higher kinetic order in pressure (0.87), and have a lower activation energy. The kinetics of the reaction as a function of hydrogen pressure, stoichiometry, and temperature for hydrogen and deuterium near ambient temperature (0 to 75 C) for pressures near or below 100 Pa over a wide range (in some cases, the complete) hydrogenation range are presented along with multi-dimensional rate models.

  5. Studies of combustion kinetics and mechanisms

    SciTech Connect (OSTI)

    Gutman, D.

    1993-12-01

    The objective of the current research is to gain new quantitative knowledge of the kinetics and mechanisms of polyatomic free radicals which are important in hydrocarbon combustion processes. The special facility designed and built for these (which includes a heatable tubular reactor coupled to a photoionization mass spectrometer) is continually being improved. Where possible, these experimental studies are coupled with theoretical ones, sometimes conducted in collaboration with others, to obtain an improved understanding of the factors determining reactivity. The decomposition of acetyl radicals, isopropyl radicals, and n-propyl radicals have been studied as well as the oxidation of methylpropargyl radicals.

  6. PBXN-9 Ignition Kinetics and Deflagration Rates

    SciTech Connect (OSTI)

    Glascoe, E; Maienschein, J; Burnham, A; Koerner, J; Hsu, P; Wemhoff, A

    2008-04-24

    The ignition kinetics and deflagration rates of PBXN-9 were measured using specially designed instruments at LLNL and compared with previous work on similar HMX based materials. Ignition kinetics were measured based on the One Dimensional Time-to-Explosion combined with ALE3D modeling. Results of these experiments indicate that PBXN-9 behaves much like other HMX based materials (i.e. LX-04, LX-07, LX-10 and PBX-9501) and the dominant factor in these experiments is the type of explosive, not the type of binder/plasticizer. In contrast, the deflagration behavior of PBXN-9 is quite different from similar high weight percent HMX based materials (i.e LX-10, LX-07 and PBX-9501). PBXN-9 burns in a laminar manner over the full pressure range studied (0-310 MPa) unlike LX-10, LX-07, and PBX-9501. The difference in deflagration behavior is attributed to the nature of the binder/plasticizer alone or in conjunction with the volume of binder present in PBXN-9.

  7. Approximate models for the ion-kinetic regime in

    Office of Scientific and Technical Information (OSTI)

    inertial-confinement-fusion capsule implosions (Journal Article) | SciTech Connect Approximate models for the ion-kinetic regime in inertial-confinement-fusion capsule implosions Citation Details In-Document Search Title: Approximate models for the ion-kinetic regime in inertial-confinement-fusion capsule implosions "Reduced" (i.e., simplified or approximate) ion-kinetic (RIK) models in radiation-hydrodynamic simulations permit a useful description of inertial-confinement-fusion

  8. Confined martensitic phase transformation kinetics and lattice dynamics in

    Office of Scientific and Technical Information (OSTI)

    Ni-Co-Fe-Ga shape memory alloys (Journal Article) | SciTech Connect Confined martensitic phase transformation kinetics and lattice dynamics in Ni-Co-Fe-Ga shape memory alloys Citation Details In-Document Search Title: Confined martensitic phase transformation kinetics and lattice dynamics in Ni-Co-Fe-Ga shape memory alloys Here we describe insights into the phase transformation kinetics and lattice dynamics associated with the newly discovered confined martensitic transformation, which are

  9. Neutron detection using a current biased kinetic inductance detector

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Neutron detection using a current biased kinetic inductance detector Citation Details In-Document Search Title: Neutron detection using a current biased kinetic inductance detector We demonstrate neutron detection using a solid state superconducting current biased kinetic inductance detector (CB-KID), which consists of a superconducting Nb meander line of 1 μm width and 40 nm thickness. {sup 10}B-enriched

  10. Spin-selective recombination kinetics of a model chemical magnetoreceptor

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spin-selective recombination kinetics of a model chemical magnetoreceptor Authors: Maeda, K., Wedge, C. J., Storey, J. G., Henbest, K. B., Liddell, P. A., Kodis, G., Gust, D., Hore, P. J., and Timmel, C. R. Title: Spin-selective recombination kinetics of a model chemical magnetoreceptor Source: Chemical Communications Year: 2011 Volume: 47 Pages: 6563-6565 ABSTRACT: We determine the spin-selective kinetics of a carotenoid-porphyrin-fullerene triad that has previously been used to establish the

  11. Ultrafast kinetics subsequent to shock in an unreacted, oxygen...

    Office of Scientific and Technical Information (OSTI)

    and hydrogen peroxide Citation Details In-Document Search Title: Ultrafast kinetics subsequent to shock in an unreacted, oxygen balanced mixture of nitromethane and hydrogen ...

  12. Uranium and Strontium Batch Sorption and Diffusion Kinetics into...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Uranium and Strontium Batch Sorption and Diffusion Kinetics into Mesoporous Silica Friday, February 27, 2015 Figure 1 Figure 1. Transmission electron microscopy images of (A)...

  13. Incorporation of aqueous reaction and sorption kinetics andbiodegradat...

    Office of Scientific and Technical Information (OSTI)

    A 1-D reactive transport problem with kinetic biodegradation and sorption was investigated, which models the processes when a pulse of water containing NTA (nitrylotriacetate) and ...

  14. Ultrafast kinetics subsequent to shock compression in an oxygen...

    Office of Scientific and Technical Information (OSTI)

    to shock compression in an oxygen-balanced mixture of nitromethane and hydrogen peroxide Citation Details In-Document Search Title: Ultrafast kinetics subsequent to shock ...

  15. Ultrafast kinetics subsequent to shock in an unreacted, oxygen...

    Office of Scientific and Technical Information (OSTI)

    shock in an unreacted, oxygen balanced mixture of nitromethane and hydrogen peroxide Citation Details In-Document Search Title: Ultrafast kinetics subsequent to shock in an ...

  16. Pressure Dependent Decomposition Kinetics of the Energetic Material...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: USDOE Country of Publication: United States Language: English Subject: 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ACCELERATION; DIAMONDS; KINETICS;...

  17. Microscale Electrode Design Using Coupled Kinetic, Thermal and...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Documents & Publications track 3: enhanced geothermal systems (EGS) | geothermal 2015 peer review Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined...

  18. Diffusion in confinement: kinetic simulations of self- and collective...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    confinement: kinetic simulations of self- and collective diffusion behavior of adsorbed gases Previous Next List M. K. F. Abouelnasr and B. Smit, PCCP 14 (33), 11600 (2012) DOI:...

  19. A Comparison of HCCI Engine Performance Data and Kinetic Modeling...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Kinetic models of fuels are needed to allow the simulation of engine performance for research, design, or verification purposes. PDF icon deer09bunting.pdf More Documents &...

  20. Laboratory support for in situ gasification reaction kinetics...

    Office of Scientific and Technical Information (OSTI)

    Laboratory support for in situ gasification reaction kinetics. Quarterly report, October--December 1976 Citation Details In-Document Search Title: Laboratory support for in situ ...

  1. MHK Projects/Ogdensburg Kinetic Energy Project | Open Energy...

    Open Energy Info (EERE)

    Project Phase Phase 1 Main Overseeing Organization AER NY Kinetics LLC Project Licensing Environmental Monitoring and Mitigation Efforts See Tethys << Return to the MHK database...

  2. Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Kinetics and Ion Mobility in Electrode Materials for Advanced Lithium Ion Batteries Materials Characterization Capabilities at the High Temperature Materials Laboratory and...

  3. Desorption Kinetics of Methanol, Ethanol, and Water from Graphene...

    Office of Scientific and Technical Information (OSTI)

    desorption kinetics would be readily apparent in the experimental TPD spectra. Authors: Smith, R. Scott ; Matthiesen, Jesper ; Kay, Bruce D. Publication Date: 2014-09-18 OSTI...

  4. Micro Hydro Kinetic Turbines from Smart Hydro Power | Open Energy...

    Open Energy Info (EERE)

    Hydro Kinetic Turbines from Smart Hydro Power Jump to: navigation, search << Return to the MHK database homepage Tauchturbine.jpg Technology Profile Project(s) where this...

  5. Effects of aqueous uranyl speciation on the kinetics of microbial...

    Office of Scientific and Technical Information (OSTI)

    Effects of aqueous uranyl speciation on the kinetics of microbial uranium reduction Citation Details In-Document Search This content will become publicly available on May 16, 2017 ...

  6. Transport Phenomena and Interfacial Kinetics in Planar Microfluidic

    Office of Scientific and Technical Information (OSTI)

    Transport Phenomena and Interfacial Kinetics in Planar Microfluidic Membraneless Fuel Cells Abruna, Hector Daniel Cornell University 30 DIRECT ENERGY CONVERSION Our work is...

  7. Kinetics, Mechanics and Microstructure Changes in Storage Media

    Broader source: Energy.gov [DOE]

    Presentation on the Kinetics, Mechanics and Microstructure Changes in Storage Media given at the DOE Theory Focus Session on Hydrogen Storage Materials on May 18, 2006.

  8. Incorporation of aqueous reaction and sorption kinetics andbiodegradat...

    Office of Scientific and Technical Information (OSTI)

    In this paper, the formulation for incorporating kinetic rates among primary species into the mass balance equations is presented. A batch sulfide oxidation problem is simulated. ...

  9. Kinetics of oxygen surface exchange on epitaxial Ruddlesden-Popper...

    Office of Scientific and Technical Information (OSTI)

    Kinetics of oxygen surface exchange on epitaxial Ruddlesden-Popper phases and correlations to first-principles descriptors Citation Details In-Document Search This content will ...

  10. Simulations of Kinetic Events at the Atomic Scale

    Broader source: Energy.gov [DOE]

    Presentation on the Simulations of Kinetic Events at the Atomic Scale given at the DOE Theory Focus Session on Hydrogen Storage Materials on May 18, 2006.

  11. Evaluation of Thermal Evolution Profiles and Estimation of Kinetic...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Evaluation of Thermal Evolution Profiles and Estimation of Kinetic ... Citation Details In-Document Search Title: Evaluation of Thermal Evolution Profiles and ...

  12. Spectroscopy, Kinetics, and Dynamics of Combustion Radicals

    SciTech Connect (OSTI)

    Nesbitt, David J.

    2013-08-06

    Spectroscopy, kinetics and dynamics of jet cooled hydrocarbon transients relevant to the DOE combustion mission have been explored, exploiting i) high resolution IR lasers, ii) slit discharge sources for formation of jet cooled radicals, and iii) high sensitivity detection with direct laser absorption methods and near the quantum shot noise limit. What makes this combination powerful is that such transients can be made under high concentrations and pressures characteristic of actual combustion conditions, and yet with the resulting species rapidly cooled (T ≈10-15K) in the slit supersonic expansion. Combined with the power of IR laser absorption methods, this provides novel access to spectral detection and study of many critical combustion species.

  13. Kinetics of wet sodium vapor complex plasma

    SciTech Connect (OSTI)

    Mishra, S. K., E-mail: nishfeb@rediffmail.com [Institute for Plasma Research (IPR), Gandhinagar 382428 (India); Sodha, M. S. [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India)] [Centre of Energy Studies, Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India)

    2014-04-15

    In this paper, we have investigated the kinetics of wet (partially condensed) Sodium vapor, which comprises of electrons, ions, neutral atoms, and Sodium droplets (i) in thermal equilibrium and (ii) when irradiated by light. The formulation includes the balance of charge over the droplets, number balance of the plasma constituents, and energy balance of the electrons. In order to evaluate the droplet charge, a phenomenon for de-charging of the droplets, viz., evaporation of positive Sodium ions from the surface has been considered in addition to electron emission and electron/ion accretion. The analysis has been utilized to evaluate the steady state parameters of such complex plasmas (i) in thermal equilibrium and (ii) when irradiated; the results have been graphically illustrated. As a significant outcome irradiated, Sodium droplets are seen to acquire large positive potential, with consequent enhancement in the electron density.

  14. Detailed Kinetic Modeling of Gasoline Surrogate Mixtures

    SciTech Connect (OSTI)

    Mehl, M; Curran, H J; Pitz, W J; Westbrook, C K

    2009-03-09

    Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, a recently revised version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multi-component gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines. Simulation results are discussed focusing attention on the mixing effects of the fuel components.

  15. Brittle failure kinetics model for concrete

    SciTech Connect (OSTI)

    Silling, S.A.

    1997-03-01

    A new constitutive model is proposed for the modeling of penetration and large stress waves in concrete. Rate effects are incorporated explicitly into the damage evolution law, hence the term brittle failure kinetics. The damage variable parameterizes a family of Mohr-Coulomb strength curves. The model, which has been implemented in the CTH code, has been shown to reproduce some distinctive phenomena that occur in penetration of concrete targets. Among these are the sharp spike in deceleration of a rigid penetrator immediately after impact. Another is the size scale effect, which leads to a nonlinear scaling of penetration depth with penetrator size. This paper discusses the theory of the model and some results of an extensive validation effort.

  16. Fully kinetic simulations of megajoule-scale dense plasma focus

    SciTech Connect (OSTI)

    Schmidt, A.; Link, A.; Tang, V.; Halvorson, C.; May, M.; Welch, D.; Meehan, B. T.; Hagen, E. C.

    2014-10-15

    Dense plasma focus (DPF) Z-pinch devices are sources of copious high energy electrons and ions, x-rays, and neutrons. Megajoule-scale DPFs can generate 10{sup 12} neutrons per pulse in deuterium gas through a combination of thermonuclear and beam-target fusion. However, the details of the neutron production are not fully understood and past optimization efforts of these devices have been largely empirical. Previously, we reported on the first fully kinetic simulations of a kilojoule-scale DPF and demonstrated that both kinetic ions and kinetic electrons are needed to reproduce experimentally observed features, such as charged-particle beam formation and anomalous resistivity. Here, we present the first fully kinetic simulation of a MegaJoule DPF, with predicted ion and neutron spectra, neutron anisotropy, neutron spot size, and time history of neutron production. The total yield predicted by the simulation is in agreement with measured values, validating the kinetic model in a second energy regime.

  17. HIGH PRESSURE COAL COMBUSTON KINETICS PROJECT

    SciTech Connect (OSTI)

    Stefano Orsino

    2005-03-30

    As part of the U.S. Department of Energy (DoE) initiative to improve the efficiency of coal-fired power plants and reduce the pollution generated by these facilities, DOE has funded the High-Pressure Coal Combustion Kinetics (HPCCK) Projects. A series of laboratory experiments were conducted on selected pulverized coals at elevated pressures with the specific goals to provide new data for pressurized coal combustion that will help extend to high pressure and validate models for burnout, pollutant formation, and generate samples of solid combustion products for analyses to fill crucial gaps in knowledge of char morphology and fly ash formation. Two series of high-pressure coal combustion experiments were performed using SRI's pressurized radiant coal flow reactor. The first series of tests characterized the near burner flame zone (NBFZ). Three coals were tested, two high volatile bituminous (Pittsburgh No.8 and Illinois No.6), and one sub-bituminous (Powder River Basin), at pressures of 1, 2, and 3 MPa (10, 20, and 30 atm). The second series of experiments, which covered high-pressure burnout (HPBO) conditions, utilized a range of substantially longer combustion residence times to produce char burnout levels from 50% to 100%. The same three coals were tested at 1, 2, and 3 MPa, as well as at 0.2 MPa. Tests were also conducted on Pittsburgh No.8 coal in CO2 entrainment gas at 0.2, 1, and 2 MPa to begin establishing a database of experiments relevant to carbon sequestration techniques. The HPBO test series included use of an impactor-type particle sampler to measure the particle size distribution of fly ash produced under complete burnout conditions. The collected data have been interpreted with the help of CFD and detailed kinetics simulation to extend and validate devolatilization, char combustion and pollutant model at elevated pressure. A global NOX production sub-model has been proposed. The submodel reproduces the performance of the detailed chemical reaction mechanism for the NBFZ tests.

  18. Advances in electron kinetics and theory of gas discharges

    SciTech Connect (OSTI)

    Kolobov, Vladimir I.; The University of Alabama in Huntsville, Huntsville, Alabama 35899

    2013-10-15

    “Electrons, like people, are fertile and infertile: high-energy electrons are fertile and able to reproduce.”—Lev TsendinModern physics of gas discharges increasingly uses physical kinetics for analysis of non-equilibrium plasmas. The description of underlying physics at the kinetic level appears to be important for plasma applications in modern technologies. In this paper, we attempt to grasp the legacy of Professor Lev Tsendin, who advocated the use of the kinetic approach for understanding fundamental problems of gas discharges. We outline the fundamentals of electron kinetics in low-temperature plasmas, describe elements of the modern kinetic theory of gas discharges, and show examples of the theoretical approach to gas discharge problems used by Lev Tsendin. Important connections between electron kinetics in gas discharges and semiconductors are also discussed. Using several examples, we illustrate how Tsendin's ideas and methods are currently being developed for the implementation of next generation computational tools for adaptive kinetic-fluid simulations of gas discharges used in modern technologies.

  19. Kinetic model for anaerobic digestion of biogas biological sludge

    SciTech Connect (OSTI)

    Pavlostathis, S.G.; Gossett, J.M.

    1986-10-01

    The principal objective of this study was the development and evaluation of a comprehensive kinetic model capable of predicting digester performance when fed biological sludge. Preliminary conversion mechanisms such as cell deaths, lysis, and hydrolysis responsible for rendering viable biological sludge organisms to available substrate were studied in depth. The results of this study indicate that hydrolysis of the dead, particulate biomass - primarily consisting of protein - is the slowest step, and therefore kinetically controls the overall process of an anaerobic digestion of biological sludge. A kinetic model was developed which could accurately describe digester performance and predict effluent quality.

  20. Kinetic model for an auroral double layer that spans many gravitationa...

    Office of Scientific and Technical Information (OSTI)

    Kinetic model for an auroral double layer that spans many gravitational scale heights Citation Details In-Document Search Title: Kinetic model for an auroral double layer that ...

  1. Zero kinetic energy photoelectron spectroscopy of triphenylene

    SciTech Connect (OSTI)

    Harthcock, Colin; Zhang, Jie; Kong, Wei

    2014-06-28

    We report vibrational information of both the first electronically excited state and the ground cationic state of jet-cooled triphenylene via the techniques of resonantly enhanced multiphoton ionization (REMPI) and zero kinetic energy (ZEKE) photoelectron spectroscopy. The first excited electronic state S{sub 1} of the neutral molecule is of A{sub 1}? symmetry and is therefore electric dipole forbidden in the D{sub 3h} group. Consequently, there are no observable Franck-Condon allowed totally symmetric a{sub 1}? vibrational bands in the REMPI spectrum. All observed vibrational transitions are due to Herzberg-Teller vibronic coupling to the E? third electronically excited state S{sub 3}. The assignment of all vibrational bands as e? symmetry is based on comparisons with calculations using the time dependent density functional theory and spectroscopic simulations. When an electron is eliminated, the molecular frame undergoes Jahn-Teller distortion, lowering the point group to C{sub 2v} and resulting in two nearly degenerate electronic states of A{sub 2} and B{sub 1} symmetry. Here we follow a crude treatment by assuming that all e? vibrational modes resolve into b{sub 2} and a{sub 1} modes in the C{sub 2v} molecular frame. Some observed ZEKE transitions are tentatively assigned, and the adiabatic ionization threshold is determined to be 63?365 7 cm{sup ?1}. The observed ZEKE spectra contain a consistent pattern, with a cluster of transitions centered near the same vibrational level of the cation as that of the intermediate state, roughly consistent with the propensity rule. However, complete assignment of the detailed vibrational structure due to Jahn-Teller coupling requires much more extensive calculations, which will be performed in the future.

  2. The LANL atomic kinetics modeling effort and its application...

    Office of Scientific and Technical Information (OSTI)

    This is the work of the LANL group on atomic kinetics modelling. There are various levels ... The LANL group plans to perform much larger calculations to assess themore accuracy of ...

  3. Pressure Dependent Decomposition Kinetics of the Energetic Material...

    Office of Scientific and Technical Information (OSTI)

    Kinetics of the Energetic Material HMX up to 3.6 GPa The effect of pressure on the thermal decomposition rate of the energetic material HMX was studied. HMX was...

  4. Benchmark Reaction Mechanisms and Kinetics for Lean NOx Traps...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon acep01larson.pdf More Documents & Publications Development of Chemical Kinetic Models for Lean NOx ...

  5. Elucidating Hydrogen Oxidation/Evolution Kinetics in Base and...

    Office of Scientific and Technical Information (OSTI)

    Elucidating Hydrogen OxidationEvolution Kinetics in Base and Acid by Enhanced Activities at the Optimized Pt Shell Thickness on the Ru Core Citation Details In-Document Search...

  6. Kinetic and Performance Studies of the Regeneration Phase of...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Phase of Model PtRhBa NOx Traps for Design and Optimization Kinetic and Performance Studies of the Regeneration Phase of Model PtRhBa NOx Traps for Design and ...

  7. Intercalation Kinetics and Ion Mobility in Electrode Materials...

    Broader source: Energy.gov (indexed) [DOE]

    es093daniel2011o.pdf More Documents & Publications Coupled Kinetic, Thermal, and Mechanical Modeling of FIB Micro-machined Electrodes In-Situ Electron Microscopy of Electrical ...

  8. Point kinetics calculations with fully coupled thermal fluids reactivity feedback

    SciTech Connect (OSTI)

    Zhang, H.; Zou, L.; Andrs, D.; Zhao, H.; Martineau, R.

    2013-07-01

    The point kinetics model has been widely used in the analysis of the transient behavior of a nuclear reactor. In the traditional nuclear reactor system safety analysis codes such as RELAP5, the reactivity feedback effects are calculated in a loosely coupled fashion through operator splitting approach. This paper discusses the point kinetics calculations with the fully coupled thermal fluids and fuel temperature feedback implemented into the RELAP-7 code currently being developed with the MOOSE framework. (authors)

  9. Evaluating the effect of potassium on cellulose pyrolysis reaction kinetics

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Journal Article: Evaluating the effect of potassium on cellulose pyrolysis reaction kinetics Citation Details In-Document Search This content will become publicly available on April 21, 2017 Title: Evaluating the effect of potassium on cellulose pyrolysis reaction kinetics Authors: Trendewicz, Anna ; Evans, Robert ; Dutta, Abhijit ; Sykes, Robert ; Carpenter, Daniel ; Braun, Robert Publication Date: 2015-03-01 OSTI Identifier: 1250597 Grant/Contract

  10. Evaluation of Thermal Evolution Profiles and Estimation of Kinetic

    Office of Scientific and Technical Information (OSTI)

    Parameters for Pyrolysis of Coal/Corn Stover Blends Using Thermogravimetric Analysis (Journal Article) | SciTech Connect Journal Article: Evaluation of Thermal Evolution Profiles and Estimation of Kinetic Parameters for Pyrolysis of Coal/Corn Stover Blends Using Thermogravimetric Analysis Citation Details In-Document Search Title: Evaluation of Thermal Evolution Profiles and Estimation of Kinetic Parameters for Pyrolysis of Coal/Corn Stover Blends Using Thermogravimetric Analysis Authors:

  11. INFRARED ABSORPTION SPECTROSCOPY AND CHEMICAL KINETICS OF FREE RADICALS

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    mNAL PERFORMANCE REPORT for INFRARED ABSORPTION SPECTROSCOPY AND CHEMICAL KINETICS OF FREE RADICALS DE-FG05-85ER13439 1-AUG-1985 to 31-JUL-1994 Robert F. Curl and Graham P. Glass Principal Investigators Introduction This research was directed at the detection, monitoring, and study (by infrared absorption spectroscopy) of the chemical kinetic behavior of small free radical species thought to be important intermediates in combustion. The work typically progressed from the detection and analysis

  12. Kinetic Simulations of Particle Acceleration at Shocks (Conference) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Kinetic Simulations of Particle Acceleration at Shocks Citation Details In-Document Search Title: Kinetic Simulations of Particle Acceleration at Shocks Collisionless shocks are mediated by collective electromagnetic interactions and are sources of non-thermal particles and emission. The full particle-in-cell approach and a hybrid approach are sketched, simulations of collisionless shocks are shown using a multicolor presentation. Results for SN 1006, a case involving ion

  13. Microfluidics: Kinetics of Hybridized DNA With Fluid Flow Variations.

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Microfluidics: Kinetics of Hybridized DNA With Fluid Flow Variations. Citation Details In-Document Search Title: Microfluidics: Kinetics of Hybridized DNA With Fluid Flow Variations. Abstract not provided. Authors: Sparks, Elizabeth Schares ; Manginell, Ronald Paul Publication Date: 2011-10-01 OSTI Identifier: 1106575 Report Number(s): SAND2011-7607C 464923 DOE Contract Number: AC04-94AL85000 Resource Type: Conference Resource Relation: Conference: MSEC 105

  14. Exploring Competing Kinetic Processes in Quantum Dots Linked to Electrode

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Surfaces | MIT-Harvard Center for Excitonics Competing Kinetic Processes in Quantum Dots Linked to Electrode Surfaces March 14, 2012 at 2:30pm/4-349 Mark Hybertsen Brookhaven National Laboratory, Columbia University Mark_Hybertsen001_000 Abstract: Exploiting the unique properties of nanostructured chromophores for light harvesting applications relies on the balance between competing kinetic processes including energy transfer, carrier relaxation and carrier tunneling. In the first part of

  15. Extraction of Equilibrium Energy and Kinetic Parameters from Single

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Molecule Force Spectroscopy Data Alex Noy is the Principal Investigator for the Extraction of Equilibrium Energy and Kinetic Parameters from Single Molecule Force Spectroscopy Data. LLNL BES Programs Highlight Extraction of Equilibrium Energy and Kinetic Parameters from Single Molecule Force Spectroscopy Data Dynamic strength data for 10 different biological bonds fitted by the model R.W. Friddle, A. Noy, J.J. De Yoreo, Interpreting the widespread nonlinear force spectra of intermolecular

  16. Transport Phenomena and Interfacial Kinetics in Planar Microfluidic

    Office of Scientific and Technical Information (OSTI)

    Membraneless Fuel Cells (Technical Report) | SciTech Connect SciTech Connect Search Results Technical Report: Transport Phenomena and Interfacial Kinetics in Planar Microfluidic Membraneless Fuel Cells Citation Details In-Document Search Title: Transport Phenomena and Interfacial Kinetics in Planar Microfluidic Membraneless Fuel Cells Our work is focused on membraneless laminar flow fuel cells, an unconventional fuel cell technology, intended to create a system that not only avoids most

  17. Ultrafast kinetics subsequent to shock in an unreacted, oxygen balanced

    Office of Scientific and Technical Information (OSTI)

    mixture of nitromethane and hydrogen peroxide (Conference) | SciTech Connect kinetics subsequent to shock in an unreacted, oxygen balanced mixture of nitromethane and hydrogen peroxide Citation Details In-Document Search Title: Ultrafast kinetics subsequent to shock in an unreacted, oxygen balanced mixture of nitromethane and hydrogen peroxide Authors: Armstrong, M R ; Zaug, J M ; Grant, C D ; Crowhurst, J C ; Bastea, S Publication Date: 2014-06-24 OSTI Identifier: 1149544 Report Number(s):

  18. Consistent description of kinetics and hydrodynamics of dusty plasma

    SciTech Connect (OSTI)

    Markiv, B.; Tokarchuk, M.; National University Lviv Polytechnic, 12 Bandera St., 79013 Lviv

    2014-02-15

    A consistent statistical description of kinetics and hydrodynamics of dusty plasma is proposed based on the Zubarev nonequilibrium statistical operator method. For the case of partial dynamics, the nonequilibrium statistical operator and the generalized transport equations for a consistent description of kinetics of dust particles and hydrodynamics of electrons, ions, and neutral atoms are obtained. In the approximation of weakly nonequilibrium process, a spectrum of collective excitations of dusty plasma is investigated in the hydrodynamic limit.

  19. Peptide concentration alters intermediate species in amyloid ? fibrillation kinetics

    SciTech Connect (OSTI)

    Garvey, M., E-mail: megan.garvey@molbiotech.rwth-aachen.de [Max-Planck Research Unit for Enzymology of Protein Folding, Weinbergweg 22, 06120 Halle (Saale) (Germany); Morgado, I., E-mail: immorgado@ualg.pt [Max-Planck Research Unit for Enzymology of Protein Folding, Weinbergweg 22, 06120 Halle (Saale) (Germany)

    2013-04-12

    Highlights: ? A?(140) aggregation in vitro has been monitored at different concentrations. ? A?(140) fibrillation does not always follow conventional kinetic mechanisms. ? We demonstrate non-linear features in the kinetics of A?(140) fibril formation. ? At high A?(140) concentrations secondary processes dictate fibrillation speed. ? Intermediate species may play significant roles on final amyloid fibril development. -- Abstract: The kinetic mechanism of amyloid aggregation remains to be fully understood. Investigations into the species present in the different kinetic phases can assist our comprehension of amyloid diseases and further our understanding of the mechanism behind amyloid ? (A?) (140) peptide aggregation. Thioflavin T (ThT) fluorescence and transmission electron microscopy (TEM) have been used in combination to monitor A?(140) aggregation in vitro at both normal and higher than standard concentrations. The observed fibrillation behaviour deviates, in several respects, from standard concepts of the nucleationpolymerisation models and shows such features as concentration-dependent non-linear effects in the assembly mechanism. A?(140) fibrillation kinetics do not always follow conventional kinetic mechanisms and, specifically at high concentrations, intermediate structures become populated and secondary processes may further modify the fibrillation mechanism.

  20. The Impact of Alternative Fuels on Combustion Kinetics

    SciTech Connect (OSTI)

    Pitz, W J; Westbrook, C K

    2009-07-30

    The research targets the development of detailed kinetic models to quantitatively characterize the impact of alternative fuels on the performance of Navy turbines and diesel engines. Such impacts include kinetic properties such as cetane number, flame speed, and emissions as well as physical properties such as the impact of boiling point distributions on fuel vaporization and mixing. The primary focus will be Fischer-Tropsch liquids made from natural gas, coal or biomass. The models will include both the effects of operation with these alternative fuels as well as blends of these fuels with conventional petroleum-based fuels. The team will develop the requisite kinetic rules for specific reaction types and incorporate these into detailed kinetic mechanisms to predict the combustion performance of neat alternative fuels as well as blends of these fuels with conventional fuels. Reduced kinetic models will be then developed to allow solution of the coupled kinetics/transport problems. This is a collaboration between the Colorado School of Mines (CSM) and the Lawrence Livermore National Laboratory (LLNL). The CSM/LLNL team plans to build on the substantial progress made in recent years in developing accurate detailed chemical mechanisms for the oxidation and pyrolysis of conventional fuels. Particular emphasis will be placed upon reactions of the isoalkanes and the daughter radicals, especially tertiary radicals, formed by abstraction from the isoalkanes. The various components of the program are described. We have been developing the kinetic models for two iso-dodecane molecules, using the same kinetic modeling formalisms that were developed for the gasoline and diesel primary reference fuels. These mechanisms, and the thermochemical and transport coefficient submodels for them, are very close to completion at the time of this report, and we expect them to be available for kinetic simulations early in the coming year. They will provide a basis for prediction and selection of desirable F-T molecules for use in jet engine simulations, where we should be able to predict the ignition, combustion and emissions characteristics of proposed fuel components. These mechanisms include the reactions and chemical species needed to describe high temperature phenomena such as shock tube ignition and flammability behavior, and they will also include low temperature kinetics to describe other ignition phenomena such as compression ignition and knocking. During the past years, our hydrocarbon kinetics modeling group at LLNL has focused a great deal on fuels typical of gasoline and diesel fuel. About 10 years ago, we developed kinetic models for the fuel octane primary reference fuels, n-heptane [1] and iso-octane [2], which have 7 and 8 carbon atoms and are therefore representative of typical gasoline fuels. N-heptane represents the low limit of knock resistance with an octane number of 0, while iso-octane is very knock resistant with an octane number of 100. High knock resistance in iso-octane was attributed largely to the large fraction of primary C-H bonds in the molecule, including 15 of the 18 C-H bonds, and the high bond energy of these primary bonds plays a large role in this knock resistance. In contrast, in the much more ignitable n-heptane, 10 of its 16 C-H bonds are much less strongly bound secondary C-H bonds, leading to its very low octane number. All of these factors, as well as a similarly complex kinetic description of the equally important role of the transition state rings that transfer H atoms within the reacting fuel molecules, were quantified and collected into large kinetic reaction mechanisms that are used by many researchers in the fuel chemistry world.

  1. Chemical Kinetic Research on HCCI & Diesel Fuels | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Chemical Kinetic Research on HCCI & Diesel Fuels Chemical Kinetic Research on HCCI & Diesel Fuels 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon ace_13_pitz.pdf More Documents & Publications Multidimensional simulation and chemical kinetics development for high efficiency clean combustion engines Chemical Kinetic Research on HCCI & Diesel Fuels Chemical Kinetic Research on

  2. The LANL atomic kinetics modeling effort and its application to W plasmas

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect The LANL atomic kinetics modeling effort and its application to W plasmas Citation Details In-Document Search Title: The LANL atomic kinetics modeling effort and its application to W plasmas This is the work of the LANL group on atomic kinetics modelling. There are various levels of detail in the LANL suite of atomic physics codes: (1) Non-relativistic configuration average kinetics (nl{sup w}) + UTA spectra, (2) Relativistic configuration average kinetics

  3. Amber Boehnlein Becomes Jefferson Lab's Chief Information Officer...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    about while on a three-year assignment with the Department of Energy's Office of High Energy Physics, where she managed the U.S. Large Hadron Collider Detector Operations program. ...

  4. Amber Boehnlein Becomes Jefferson Lab's Chief Information Officer; Takes

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Administration Ambassador Ensher visits Y-12 and NNSS Monday, April 25, 2016 - 10:30am Stuart Rawlinson, left, of the Nevada National Security Site, explains the layout of the "P" Tunnel complex to Ambassador Henry Ensher, center, Chargé d'Affaires U.S. Mission to International Organizations in Vienna and others. The "P" Tunnel was used during underground nuclear explosive testing, which ended in 1992, by the Defense Threat Reduction Agency to understand the effects of

  5. Kinetic Alfvn wave turbulence and formation of localized structures

    SciTech Connect (OSTI)

    Sharma, R. P.; Modi, K. V.; Mechanical Engineering Department, Government Engineering College Valsad, Gujarat 396001

    2013-08-15

    This work presents non-linear interaction of magnetosonic wave with kinetic Alfvn wave for intermediate ?-plasma (m{sub e}/m{sub i}???1). A set of dimensionless equations have been developed for analysis by considering ponderomotive force due to pump kinetic Alfvn wave in the dynamics of magnetosonic wave. Stability analysis has been done to study modulational instability or linear growth rate. Further, numerical simulation has been carried out to study the nonlinear stage of instability and resulting power spectrum applicable to solar wind around 1 AU. Due to the nonlinearity, background density of magnetosonic wave gets modified which results in localization of kinetic Alfvn wave. From the obtained results, we observed that spectral index follows k{sup ?3.0}, consistent with observation received by Cluster spacecraft for the solar wind around 1 AU. The result shows the steepening of power spectrum which may be responsible for heating and acceleration of plasma particles in solar wind.

  6. Kinetics of high-conversion hydrocracking of bitumen

    SciTech Connect (OSTI)

    Nagaishi, H.; Gray, M.R.; Chan, E.W.; Sanford, E.C.

    1995-12-31

    Residues are complex mixtures of thousands of components. This mixture will change during hydrocracking, so that high conversion may result in a residue material with different characteristics from the starting material. Our objective is to determine the kinetics of residue conversion and yields of distillates at high conversions, and to relate these observations to the underlying chemical reactions. Athabasca bitumen was reacted in a 1-L CSTR in a multipass operation. Product from the first pass was collected, then run through the reactor again and so on, giving kinetic data under conditions that simulated a multi-reactor or packed-bed operation. Experiments were run both with hydrocracking catalyst and without added catalyst. Products were analyzed by distillation, elemental analysis, NMR, and GPC. These data will be used to derive a kinetic model for hydrocracking of bitumen residue covering a wide range of conversion (from 30% to 95%+), based on the underlying chemistry.

  7. Chemical Kinetic Models for HCCI and Diesel Combustion

    SciTech Connect (OSTI)

    Pitz, W J; Westbrook, C K; Mehl, M; Sarathy, S M

    2010-11-15

    Predictive engine simulation models are needed to make rapid progress towards DOE's goals of increasing combustion engine efficiency and reducing pollutant emissions. These engine simulation models require chemical kinetic submodels to allow the prediction of the effect of fuel composition on engine performance and emissions. Chemical kinetic models for conventional and next-generation transportation fuels need to be developed so that engine simulation tools can predict fuel effects. The objectives are to: (1) Develop detailed chemical kinetic models for fuel components used in surrogate fuels for diesel and HCCI engines; (2) Develop surrogate fuel models to represent real fuels and model low temperature combustion strategies in HCCI and diesel engines that lead to low emissions and high efficiency; and (3) Characterize the role of fuel composition on low temperature combustion modes of advanced combustion engines.

  8. Kinetics of the carbon monoxide oxidation reaction under microwave heating

    SciTech Connect (OSTI)

    Perry, W.L.; Katz, J.D.; Rees, D.; Paffett, M.T. [Los Alamos National Lab., NM (United States); Datye, A. [Univ. of New Mexico, Albuquerque, NM (United States)

    1996-06-01

    915 MHz microwave heating has been used to drive the CO oxidation reaction over Pd/Al{sub 2}O{sub 3} with out significantly affecting the reaction kinetics. As compared to an identical conventionally heated system, the activation energy, pre-exponential factor, and reaction order with respect to CO were unchanged. Temperature was measured using a thermocouple extrapolation technique. Microwave-induced thermal gradients were found to play a significant role in kinetic observations. The authors chose the CO oxidation reaction over a supported metal catalyst because the reaction kinetics are well known, and because of the diverse dielectric properties of the various elements in the system: CO is a polar molecule, O{sub 2} and CO{sub 2} are non-polar, Al{sub 2}O{sub 3} is a dielectric, and Pt and Pd are conductors.

  9. Performance of non-conventional factorization approaches for neutron kinetics

    SciTech Connect (OSTI)

    Bulla, S.; Nervo, M.

    2013-07-01

    The use of factorization techniques provides a interesting option for the simulation of the time-dependent behavior of nuclear systems with a reduced computational effort. While point kinetics neglects all spatial and spectral effects, quasi-statics and multipoint kinetics allow to produce results with a higher accuracy for transients involving relevant modifications of the neutron distribution. However, in some conditions these methods can not work efficiently. In this paper, we discuss some possible alternative formulations for the factorization process for neutron kinetics, leading to mathematical models of reduced complications that can allow an accurate simulation of transients involving spatial and spectral effects. The performance of these innovative approaches are compared to standard techniques for some test cases, showing the benefits and shortcomings of the method proposed. (authors)

  10. Computer-Aided Construction of Chemical Kinetic Models

    SciTech Connect (OSTI)

    Green, William H.

    2014-12-31

    The combustion chemistry of even simple fuels can be extremely complex, involving hundreds or thousands of kinetically significant species. The most reasonable way to deal with this complexity is to use a computer not only to numerically solve the kinetic model, but also to construct the kinetic model in the first place. Because these large models contain so many numerical parameters (e.g. rate coefficients, thermochemistry) one never has sufficient data to uniquely determine them all experimentally. Instead one must work in predictive mode, using theoretical rather than experimental values for many of the numbers in the model, and as appropriate refining the most sensitive numbers through experiments. Predictive chemical kinetics is exactly what is needed for computer-aided design of combustion systems based on proposed alternative fuels, particularly for early assessment of the value and viability of proposed new fuels before those fuels are commercially available. This project was aimed at making accurate predictive chemical kinetics practical; this is a challenging goal which requires a range of science advances. The project spanned a wide range from quantum chemical calculations on individual molecules and elementary-step reactions, through the development of improved rate/thermo calculation procedures, the creation of algorithms and software for constructing and solving kinetic simulations, the invention of methods for model-reduction while maintaining error control, and finally comparisons with experiment. Many of the parameters in the models were derived from quantum chemistry calculations, and the models were compared with experimental data measured in our lab or in collaboration with others.

  11. Benchmarking kinetic calculations of resistive wall mode stability

    SciTech Connect (OSTI)

    Berkery, J. W.; Sabbagh, S. A.; Liu, Y. Q.; Betti, R.

    2014-05-15

    Validating the calculations of kinetic resistive wall mode (RWM) stability is important for confidently predicting RWM stable operating regions in ITER and other high performance tokamaks for disruption avoidance. Benchmarking the calculations of the Magnetohydrodynamic Resistive SpectrumKinetic (MARS-K) [Y. Liu et al., Phys. Plasmas 15, 112503 (2008)], Modification to Ideal Stability by Kinetic effects (MISK) [B. Hu et al., Phys. Plasmas 12, 057301 (2005)], and Perturbed Equilibrium Nonambipolar Transport (PENT) [N. Logan et al., Phys. Plasmas 20, 122507 (2013)] codes for two Solov'ev analytical equilibria and a projected ITER equilibrium has demonstrated good agreement between the codes. The important particle frequencies, the frequency resonance energy integral in which they are used, the marginally stable eigenfunctions, perturbed Lagrangians, and fluid growth rates are all generally consistent between the codes. The most important kinetic effect at low rotation is the resonance between the mode rotation and the trapped thermal particle's precession drift, and MARS-K, MISK, and PENT show good agreement in this term. The different ways the rational surface contribution was treated historically in the codes is identified as a source of disagreement in the bounce and transit resonance terms at higher plasma rotation. Calculations from all of the codes support the present understanding that RWM stability can be increased by kinetic effects at low rotation through precession drift resonance and at high rotation by bounce and transit resonances, while intermediate rotation can remain susceptible to instability. The applicability of benchmarked kinetic stability calculations to experimental results is demonstrated by the prediction of MISK calculations of near marginal growth rates for experimental marginal stability points from the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)].

  12. General non-minimal kinetic coupling to gravity

    SciTech Connect (OSTI)

    Granda, L.N.; Cardona, W. E-mail: wilalbca@univalle.edu.co

    2010-07-01

    We study a model of scalar field with a general non-minimal kinetic coupling to itself and to the curvature, as a source of dark energy, and analyze the cosmological dynamics of this model and the issue of accelerated expansion. Solutions giving rise to power-law expansion have been found. The dynamical equation of state is studied for the two cases, without and with free kinetic term . In the first case, a behavior very close to that of the cosmological constant was found. In the second case, a solution was found, which match the current phenomenology of the dark energy. The model shows a rich variety of dynamical scenarios.

  13. Moisture desorption rates from TATB-formulations: experiments and kinetic

    Office of Scientific and Technical Information (OSTI)

    models (Journal Article) | SciTech Connect Moisture desorption rates from TATB-formulations: experiments and kinetic models Citation Details In-Document Search Title: Moisture desorption rates from TATB-formulations: experiments and kinetic models Authors: Glascoe, E A ; Dinh, L N ; Small, W ; Overturf, G E Publication Date: 2012-01-19 OSTI Identifier: 1093909 Report Number(s): LLNL-JRNL-528991 Journal ID: ISSN 1089-5639 DOE Contract Number: W-7405-ENG-48 Resource Type: Journal Article

  14. A coke oven model including thermal decomposition kinetics of tar

    SciTech Connect (OSTI)

    Munekane, Fuminori; Yamaguchi, Yukio; Tanioka, Seiichi

    1997-12-31

    A new one-dimensional coke oven model has been developed for simulating the amount and the characteristics of by-products such as tar and gas as well as coke. This model consists of both heat transfer and chemical kinetics including thermal decomposition of coal and tar. The chemical kinetics constants are obtained by estimation based on the results of experiments conducted to investigate the thermal decomposition of both coal and tar. The calculation results using the new model are in good agreement with experimental ones.

  15. Recent advances in the kinetics of oxygen reduction

    SciTech Connect (OSTI)

    Adzic, R.

    1996-07-01

    Oxygen reduction is considered an important electrocatalytic reaction; the most notable need remains improvement of the catalytic activity of existing metal electrocatalysts and development of new ones. A review is given of new advances in the understanding of reaction kinetics and improvements of the electrocatalytic properties of some surfaces, with focus on recent studies of relationship of the surface properties to its activity and reaction kinetics. The urgent need is to improve catalytic activity of Pt and synthesize new, possibly non- noble metal catalysts. New experimental techniques for obtaining new level of information include various {ital in situ} spectroscopies and scanning probes, some involving synchrotron radiation. 138 refs, 18 figs, 2 tabs.

  16. Spectroscopy and kinetics of combustion gases at high temperatures

    SciTech Connect (OSTI)

    Hanson, R.K.; Bowman, C.T.

    1993-12-01

    This program involves two complementary activities: (1) development and application of cw ring dye laser absorption methods for sensitive detection of radical species and measurement of fundamental spectroscopic parameters at high temperatures; and (2) shock tube studies of reaction kinetics relevant to combustion. Species currently under investigation in the spectroscopic portion of the research include NO and CH{sub 3}; this has necessitated the continued operated at wavelengths in the range 210-230 nm. Shock tube studies of reaction kinetics currently are focussed on reactions involving CH{sub 3} radicals.

  17. Infrared absorption spectroscopy and chemical kinetics of free radicals

    SciTech Connect (OSTI)

    Curl, R.F.; Glass, G.P.

    1993-12-01

    This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

  18. Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate

    SciTech Connect (OSTI)

    Herbinet, O; Pitz, W J; Westbrook, C K

    2007-09-17

    A detailed chemical kinetic mechanism has been developed and used to study the oxidation of methyl decanoate, a surrogate for biodiesel fuels. This model has been built by following the rules established by Curran et al. for the oxidation of n-heptane and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results have been compared with methyl decanoate experiments in an engine and oxidation of rapeseed oil methyl esters in a jet stirred reactor. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. These model capabilities indicate that large n-alkanes can be good surrogates for large methyl esters and biodiesel fuels to predict overall reactivity, but some kinetic details, including early CO2 production from biodiesel fuels, can be predicted only by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.

  19. Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate

    SciTech Connect (OSTI)

    Herbinet, O; Pitz, W J; Westbrook, C K

    2007-09-20

    A detailed chemical kinetic mechanism has been developed and used to study the oxidation of methyl decanoate, a surrogate for biodiesel fuels. This model has been built by following the rules established by Curran et al. for the oxidation of n-heptane and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results have been compared with methyl decanoate experiments in an engine and oxidation of rapeseed oil methyl esters in a jet stirred reactor. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. These model capabilities indicate that large n-alkanes can be good surrogates for large methyl esters and biodiesel fuels to predict overall reactivity, but some kinetic details, including early CO{sub 2} production from biodiesel fuels, can be predicted only by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.

  20. Desorption Kinetics of Methanol, Ethanol, and Water from Graphene

    SciTech Connect (OSTI)

    Smith, R. Scott; Matthiesen, Jesper; Kay, Bruce D.

    2014-09-18

    The desorption kinetics of methanol, ethanol, and water from graphene covered Pt(111) are investigated. The temperature programmed desorption (TPD) spectra for both methanol and ethanol have well-resolved first, second, third, and multilayer layer desorption peaks. The alignment of the leading edges is consistent with zero-order desorption kinetics from all layers. In contrast, for water the first and second layers are not resolved. At low water coverages (< 1 ML) the initial desorption leading edges are aligned but then fall out of alignment at higher temperatures. For thicker water layers (10 to 100 ML), the desorption leading edges are in alignment throughout the desorption of the film. The coverage dependence of the desorption behavoir suggests that at low water coverages the non-alignment of the desorption leading edges is due to water dewetting from the graphene substrate. Kinetic simulations reveal that the experimental results are consistent with zero-order desorption. The simulations also show that fractional order desorption kinetics would be readily apparent in the experimental TPD spectra.

  1. Detailed chemical kinetic oxidation mechanism for a biodiesel surrogate

    SciTech Connect (OSTI)

    Herbinet, Olivier; Pitz, William J.; Westbrook, Charles K.

    2008-08-15

    A detailed chemical kinetic mechanism has been developed and used to study the oxidation of methyl decanoate, a surrogate for biodiesel fuels. This model has been built by following the rules established by Curran and co-workers for the oxidation of n-heptane and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results have been compared with methyl decanoate experiments in an engine and oxidation of rapeseed oil methyl esters in a jet-stirred reactor. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. These model capabilities indicate that large n-alkanes can be good surrogates for large methyl esters and biodiesel fuels to predict overall reactivity, but some kinetic details, including early CO{sub 2} production from biodiesel fuels, can be predicted only by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels. (author)

  2. KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYNTHESIS

    SciTech Connect (OSTI)

    Dragomir B. Bukur; Gilbert F. Froment; Tomasz Olewski

    2006-09-29

    This report covers the fourth year of a research project conducted under the University Coal Research Program. The overall objective of this project is to develop a comprehensive kinetic model for slurry-phase Fischer-Tropsch synthesis (FTS) employing iron-based catalysts. This model will be validated with experimental data obtained in a stirred-tank slurry reactor (STSR) over a wide range of process conditions. The model will be able to predict molar flow rates and concentrations of all reactants and major product species (water, carbon dioxide, linear 1- and 2-olefins, and linear paraffins) as a function of reaction conditions in the STSR. During the fourth year of the project, an analysis of experimental data collected during the second year of this project was performed. Kinetic parameters were estimated utilizing product distributions from 27 mass balances. During the reporting period two kinetic models were employed: a comprehensive kinetic model of Dr. Li and co-workers (Yang et al., 2003) and a hydrocarbon selectivity model of Van der Laan and Beenackers (1998, 1999) The kinetic model of Yang et al. (2003) has 24 parameters (20 parameters for hydrocarbon formation, and 4 parameters for the water-gas-shift (WGS) reaction). Kinetic parameters for the WGS reaction and FTS synthesis were estimated first separately, and then simultaneously. The estimation of these kinetic parameters employed the Levenberg-Marquardt (LM) method and the trust-region reflective Newton large-scale (LS) method. A genetic algorithm (GA) was incorporated into estimation of parameters for FTS reaction to provide initial estimates of model parameters. All reaction rate constants and activation energies were found to be positive, but at the 95% confidence level the intervals were large. Agreement between predicted and experimental reaction rates has been fair to good. Light hydrocarbons are predicted fairly accurately, whereas the model underpredicts values of higher molecular weight hydrocarbons. Van der Laan and Beenackers hydrocarbon selectivity model provides a very good fit of the experimental data for hydrocarbons up to about C{sub 20}. However, the experimental data shows higher paraffin formation rates in C{sub 12}-C{sub 25} region which is likely due to hydrocracking or other secondary reactions. The model accurately captures the observed experimental trends of decreasing olefin to paraffin ratio and increasing {alpha} (chain growth length) with increase in chain length.

  3. Approximate models for the ion-kinetic regime ininertial-confinement...

    Office of Scientific and Technical Information (OSTI)

    Approximate models for the ion-kinetic regime in inertial-confinement-fusion capsule implosions Citation Details In-Document Search Title: Approximate models for the ion-kinetic ...

  4. Fully Kinetic Simulations of MegaJoule-Scale Dense Plasma Focus...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Fully Kinetic Simulations of MegaJoule-Scale Dense Plasma Focus Citation Details In-Document Search Title: Fully Kinetic Simulations of MegaJoule-Scale Dense ...

  5. Kinetics of Slurry Phase Fischer-Tropsch Synthesis

    SciTech Connect (OSTI)

    Dragomir B. Bukur; Gilbert F. Froment; Tomasz Olewski; Lech Nowicki; Madhav Nayapati

    2006-12-31

    The overall objective of this project is to develop a comprehensive kinetic model for slurry-phase Fischer-Tropsch synthesis (FTS) employing iron-based catalysts. This model will be validated with experimental data obtained in a stirred-tank slurry reactor (STSR) over a wide range of process conditions. Three STSR tests of the Ruhrchemie LP 33/81 catalyst were conducted to collect data on catalyst activity and selectivity under 25 different sets of process conditions. The observed decrease in 1-olefin content and increase in 2-olefin and n-paraffin contents with the increase in conversion are consistent with a concept that 1-olefins participate in secondary reactions (e.g. 1-olefin hydrogenation, isomerization and readsorption), whereas 2-olefins and n-paraffins are formed in these reactions. Carbon number product distribution showed an increase in chain growth probability with increase in chain length. Vapor-liquid equilibrium calculations were made to check validity of the assumption that the gas and liquid phases are in equilibrium during FTS in the STSR. Calculated vapor phase compositions were in excellent agreement with experimental values from the STSR under reaction conditions. Discrepancies between the calculated and experimental values for the liquid-phase composition (for some of the experimental data) are ascribed to experimental errors in the amount of wax collected from the reactor, and the relative amounts of hydrocarbon wax and Durasyn 164 oil (start-up fluid) in the liquid samples. Kinetic parameters of four kinetic models (Lox and Froment, 1993b; Yang et al., 2003; Van der Laan and Beenackers, 1998, 1999; and an extended kinetic model of Van der Laan and Beenackers) were estimated from experimental data in the STSR tests. Two of these kinetic models (Lox and Froment, 1993b; Yang et al., 2003) can predict a complete product distribution (inorganic species and hydrocarbons), whereas the kinetic model of Van der Laan and Beenackers (1998, 1999) can be used only to fit product distribution of total olefins and n-paraffins. The kinetic model of Van der Laan and Beenackers was extended to account separately for formation of 1- and 2-olefins, as well as n-paraffins. A simplified form of the kinetic model of Lox and Froment (1993b) has only five parameters at isothermal conditions. Because of its relative simplicity, this model is well suited for initial studies where the main goal is to learn techniques for parameter estimation and statistical analysis of estimated values of model parameters. The same techniques and computer codes were used in the analysis of other kinetic models. The Levenberg-Marquardt (LM) method was employed for minimization of the objective function and kinetic parameter estimation. Predicted reaction rates of inorganic and hydrocarbon species were not in good agreement with experimental data. All reaction rate constants and activation energies (24 parameters) of the Yang et al. (2003) model were found to be positive, but the corresponding 95% confidence intervals were large. Agreement between predicted and experimental reaction rates has been fair to good. Light hydrocarbons were predicted fairly accurately, whereas the model predictions of higher molecular weight hydrocarbons values were lower than the experimental ones. The Van der Laan and Beenackers kinetic model (known as olefin readsorption product distribution model = ORPDM) provided a very good fit of the experimental data for hydrocarbons (total olefins and n-paraffins) up to about C{sub 20} (with the exception of experimental data that showed higher paraffin formation rates in C{sub 12}-C{sub 25} region, due to hydrocracking or other secondary reactions). Estimated values of all model parameters (true and pseudo-kinetic parameters) had high statistical significance after combining parameters related to olefin termination and readsorption into one (total of 7 model parameters). The original ORPDM was extended to account separately for formation of 1- and 2-olefins, and successfully employed to fit experimental data of three major groups of hydrocarbon products (n-paraffins, 1-olefins and 2-olefins). This model is referred to as an extended ORPDM (8 model parameters in its final form). In general, all three groups of products were fitted well, and the estimated model parameters were all positive and the corresponding 95% confidence intervals were small. Even though the extended ORPDM provided a very good fit of experimental data, it can not be used for the prediction of product distributions for a given set of process conditions. This model has several pseudo-kinetic parameters whose values vary with process conditions. Additional work is needed to expand capabilities of the model to predict molar flow rates of all inorganic species and major hydrocarbon products in terms of true kinetic (temperature dependent) constants.

  6. KINETIC MODELING OF FUEL EFFECTS OVER A WIDE RANGE OF CHEMISTRY...

    Office of Scientific and Technical Information (OSTI)

    Methodologies needed for studying fuel effects include development of fuel kinetic ... Resource Relation: Conference: International Conference on Sustainable Automotive ...

  7. Chemical Kinetic Modeling of Non-Petroleum Based Fuels | Department of

    Broader source: Energy.gov (indexed) [DOE]

    Energy 2 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting PDF icon ft010_pitz_2012_o.pdf More Documents & Publications Chemical Kinetic Modeling of Non-Petroleum Based Fuels Chemical Kinetic Modeling of Fuels Chemical Kinetic Research on HCCI & Diesel Fuels

  8. Chemical Kinetic Modeling of Non-Petroleum Based Fuels | Department of

    Broader source: Energy.gov (indexed) [DOE]

    Energy 1 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation PDF icon ft010_pitz_2011_o.pdf More Documents & Publications Chemical Kinetic Modeling of Non-Petroleum Based Fuels Chemical Kinetic Modeling of Fuels Simulation of High Efficiency Clean Combustion Engines and Detailed Chemical Kinetic Mechanisms Development

  9. Chemical Kinetic Research on HCCI & Diesel Fuels | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    1 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation PDF icon ace013_pitz_2011_o.pdf More Documents & Publications Chemical Kinetic Research on HCCI & Diesel Fuels Chemical Kinetics Research on HCCI and Diesel Fuels Chemical Kinetic Research on HCCI & Diesel Fuels

  10. Development of Chemical Kinetic Models for Lean NOx Traps | Department of

    Broader source: Energy.gov (indexed) [DOE]

    Energy 1 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation PDF icon ace035_larson_2011_o.pdf More Documents & Publications Development of Chemical Kinetic Models for Lean NOx Traps Benchmark Reaction Mechanisms and Kinetics for Lean NOx Traps CLEERS Coordination & Development of Catalyst Process Kinetic Data

  11. Complexity reduction of collisional-radiative kinetics for atomic plasma

    SciTech Connect (OSTI)

    Le, Hai P.; Karagozian, Ann R.; Cambier, Jean-Luc

    2013-12-15

    Thermal non-equilibrium processes in partially ionized plasmas can be most accurately modeled by collisional-radiative kinetics. This level of detail is required for an accurate prediction of the plasma. However, the resultant system of equations can be prohibitively large, making multi-dimensional and unsteady simulations of non-equilibrium radiating plasma particularly challenging. In this paper, we present a scheme for model reduction of the collisional-radiative kinetics, by combining energy levels into groups and deriving the corresponding macroscopic rates for all transitions. Although level-grouping is a standard approach to this type of problem, we provide here a mechanism for achieving higher-order accuracy by accounting for the level distribution within a group. The accuracy and benefits of the scheme are demonstrated for the generic case of atomic hydrogen by comparison with the complete solution of the master rate equations and other methods.

  12. On consistent kinetic and derivative interactions for gravitons

    SciTech Connect (OSTI)

    Noller, Johannes

    2015-04-17

    The only known fully ghost-free and consistent Lorentz-invariant kinetic term for a graviton (or indeed for any spin-2 field) is the Einstein-Hilbert term. Here we propose and investigate a new candidate family of kinetic interactions and their extensions to derivative interactions involving several spin-2 fields. These new terms generically break diffeomorphism invariance(s) and as a result can lead to the propagation of 5 degrees of freedom for a single spin-2 field — analogous to ghost-free Massive Gravity. We discuss under what circumstances these new terms can be used to build healthy effective field theories and in the process establish the ‘Jordan’ and ‘Einstein’ frame pictures for Massive-, Bi- and Multi-Gravity.

  13. Systems engineering analysis of kinetic energy weapon concepts

    SciTech Connect (OSTI)

    Senglaub, M.

    1996-06-01

    This study examines, from a systems engineering design perspective, the potential of kinetic energy weapons being used in the role of a conventional strategic weapon. Within the Department of Energy (DOE) complex, strategic weapon experience falls predominantly in the nuclear weapons arena. The techniques developed over the years may not be the most suitable methodologies for use in a new design/development arena. For this reason a more fundamental approach was pursued with the objective of developing an information base from which design decisions might be made concerning the conventional strategic weapon system concepts. The study examined (1) a number of generic missions, (2) the effects of a number of damage mechanisms from a physics perspective, (3) measures of effectiveness (MOE`s), and (4) a design envelope for kinetic energy weapon concepts. With the base of information a cut at developing a set of high-level system requirements was made, and a number of concepts were assessed against these requirements.

  14. RESOLUTION OF URANIUM ISOTOPES WITH KINETIC PHOSPHORESCENCE ANALYSIS

    SciTech Connect (OSTI)

    Miley, Sarah M.; Hylden, Anne T.; Friese, Judah I.

    2013-04-01

    This study was conducted to test the ability of the Chemchek Kinetic Phosphorescence Analyzer Model KPA-11 with an auto-sampler to resolve the difference in phosphorescent decay rates of several different uranium isotopes, and therefore identify the uranium isotope ratios present in a sample. Kinetic phosphorescence analysis (KPA) is a technique that provides rapid, accurate, and precise determination of uranium concentration in aqueous solutions. Utilizing a pulsed-laser source to excite an aqueous solution of uranium, this technique measures the phosphorescent emission intensity over time to determine the phosphorescence decay profile. The phosphorescence intensity at the onset of decay is proportional to the uranium concentration in the sample. Calibration with uranium standards results in the accurate determination of actual concentration of the sample. Different isotopes of uranium, however, have unique properties which should result in different phosphorescence decay rates seen via KPA. Results show that a KPA is capable of resolving uranium isotopes.

  15. Kinetic behavior of potassium bicarbonate crystallization in a

    Office of Scientific and Technical Information (OSTI)

    carbonate-based CO2 absorption process (Journal Article) | SciTech Connect behavior of potassium bicarbonate crystallization in a carbonate-based CO2 absorption process Citation Details In-Document Search This content will become publicly available on September 17, 2016 Title: Kinetic behavior of potassium bicarbonate crystallization in a carbonate-based CO2 absorption process Authors: Ye, Qing ; Wang, Xinlei ; Lu, Yongqi Publication Date: 2015-01-01 OSTI Identifier: 1250242 Grant/Contract

  16. Elucidating the Complex Recombination Kinetics in Organic-Inorganic

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Trihalide Perovskites* | MIT-Harvard Center for Excitonics Elucidating the Complex Recombination Kinetics in Organic-Inorganic Trihalide Perovskites* December 8, 2015 at 4:30pm/36-428 Dane de Quilettes University of Washington deQuilettes-2 Solution processed semiconductors are often plagued by performance limiting defects, surprisingly organometal trihalide perovskites (e.g. CH3NH3PbI3) have exhibited excellent photovoltaic power conversion efficiencies comparable to meticulously refined

  17. Kinetically tuned dimensional augmentation as a versatile synthetic route

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    towards robust metal-organic frameworks | Center for Gas SeparationsRelevant to Clean Energy Technologies | Blandine Jerome Kinetically tuned dimensional augmentation as a versatile synthetic route towards robust metal-organic frameworks Previous Next List Dawei Feng, Kecheng Wang, Zhangwen Wei, Ying-Pin Chen, Cory M. Simon, Ravi K. Arvapally, Richard L. Martin, Mathieu Bosch, Tian-Fu Liu, Stephen Fordham, Daqiang Yuan, Mohammad A. Omary, Maciej Haranczyk, Berend Smit & Hong-Cai Zhou,

  18. Kinetic theory of nonlinear transport phenomena in complex plasmas

    SciTech Connect (OSTI)

    Mishra, S. K. [Institute for Plasma Research (IPR), Gandhinagar 382428 (India); Sodha, M. S. [Centre for Energy Studies (CES), Indian Institute of Technology Delhi (IITD), New Delhi 110016 (India)

    2013-03-15

    In contrast to the prevalent use of the phenomenological theory of transport phenomena, a number of transport properties of complex plasmas have been evaluated by using appropriate expressions, available from the kinetic theory, which are based on Boltzmann's transfer equation; in particular, the energy dependence of the electron collision frequency has been taken into account. Following the recent trend, the number and energy balance of all the constituents of the complex plasma and the charge balance on the particles is accounted for; the Ohmic loss has also been included in the energy balance of the electrons. The charging kinetics for the complex plasma comprising of uniformly dispersed dust particles, characterized by (i) uniform size and (ii) the Mathis, Rumpl, and Nordsieck power law of size distribution has been developed. Using appropriate expressions for the transport parameters based on the kinetic theory, the system of equations has been solved to investigate the parametric dependence of the complex plasma transport properties on the applied electric field and other plasma parameters; the results are graphically illustrated.

  19. Effect of morphology of hydrophobic surfaces on cavitation kinetics

    SciTech Connect (OSTI)

    LUZAR,ALENKA; LEUNG,KEVIN

    2000-04-24

    Cavitation has been suggested to be a possible source of long range interactions between mesoscopic hydrophobic surfaces. While evaporation is predicted by thermodynamics, little is known about its kinetics. Glauber dynamics Monte Carlo simulations of a lattice gas close to liquid-gas coexistence and confined between partially drying surfaces are used to model the effect of water confinement on the dynamics of surface-induced phase transition. Specifically, they examine how kinetics of induced evaporation change as the texture of hydrophobic surfaces is varied. Evaporation rates are considerably slowed with relatively small amount of hydrophilic coverage. However, the distribution of hydrophilic patches is found to be crucial, with the homogeneous one being much more effective in slowing the formation of vapor tubes which triggers the evaporation process. They estimate the free energy barrier of vapor tube formation via transition state theory, using a constrained forward-backward umbrella sampling technique applied to the metastable, confined liquid. Furthermore, to relate simulation rates to experimental ones, they perform simulations using the mass-conserving Kawasaki algorithm. They predict evaporation time scales that range from hundreds of picoseconds in the case of mesoscopic surfaces {approximately} 10{sup 4} nm{sup 2} to tens of nanoseconds for smaller surfaces {approximately} 40 nm{sup 2}, when the two surfaces are {approximately} 10 solvent layers apart. The present study demonstrates that cavitation is kinetically viable in real systems and should be considered in studies of processes at confined geometry.

  20. Kinetic and reactor models for HDT of middle distillates

    SciTech Connect (OSTI)

    Cotta, R.M.; Filho, R.M.

    1996-12-31

    Hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) of middle distillates over a commercial Ni-Mo/y-Al{sub 2}O{sub 3} has been studied under wide operating conditions just as 340 to 380{degrees}C and 38 to 98 atm. A Power Law model was presented to each one of those reactions. The parameters of kinetic equations were estimated solving the ordinary differential equations by the 4 order Runge-Kutta-Gill algorithm and Marquardt method for searching of set of kinetic parameters (kinetic constants as well as the orders of reactions). An adiabatic diesel hydrotreating trickle-bed reactor packed with the same catalyst was simulated numerically in order to check up the behavior of this specific reaction system. One dimensional pseudo-homogeneous model was used in this work. For each feed, the mass and energy balance equations were integrated along the length of the catalytic bed using the 4th Runge-Kutta-Gill method. The performance of two industrial reactors was checked. 5 refs., 2 tabs.

  1. A Pore Scale Evaluation of the Kinetics of Mineral Dissolution and Precipitation Reactions (EMSI)

    SciTech Connect (OSTI)

    Steefel, Carl I.

    2006-06-01

    The chief goals for CEKA are to (1) collect and synthesize molecular-level kinetic data into a coherent framework that can be used to predict time evolution of environmental processes over a range of temporal and spatial scales; (2) train a cohort of talented and diverse students to work on kinetic problems at multiple scales; (3) develop and promote the use of new experimental techniques in environmental kinetics; (4) develop and promote the use of new modeling tools to conceptualize reaction kinetics in environmental systems; and (5) communicate our understanding of issues related to environmental kinetics and issues of scale to the broader scientific community and to the public.

  2. KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYSTHESIS

    SciTech Connect (OSTI)

    Dragomir B. Bukur; Gilbert F. Froment; Tomasz Olewski

    2005-09-29

    This report covers the third year of this research grant under the University Coal Research program. The overall objective of this project is to develop a comprehensive kinetic model for slurry phase Fischer-Tropsch synthesis (FTS) on iron catalysts. This model will be validated with experimental data obtained in a stirred tank slurry reactor (STSR) over a wide range of process conditions. The model will be able to predict molar flow rates and concentrations of all reactants and major product species (H{sub 2}O, CO{sub 2}, linear 1- and 2-olefins, and linear paraffins) as a function of reaction conditions in the STSR. During the reporting period we utilized experimental data from the STSR, that were obtained during the first two years of the project, to perform vapor-liquid equilibrium (VLE) calculations and estimate kinetic parameters. We used a modified Peng-Robinson (PR) equation of state (EOS) with estimated values of binary interaction coefficients for the VLE calculations. Calculated vapor phase compositions were in excellent agreement with experimental values from the STSR under reaction conditions. Occasional discrepancies (for some of the experimental data) between calculated and experimental values of the liquid phase composition were ascribed to experimental errors. The VLE calculations show that the vapor and the liquid are in thermodynamic equilibrium under reaction conditions. Also, we have successfully applied the Levenberg-Marquardt method (Marquardt, 1963) to estimate parameters of a kinetic model proposed earlier by Lox and Froment (1993b) for FTS on an iron catalyst. This kinetic model is well suited for initial studies where the main goal is to learn techniques for parameter estimation and statistical analysis of estimated values of model parameters. It predicts that the chain growth parameter ({alpha}) and olefin to paraffin ratio are independent of carbon number, whereas our experimental data show that they vary with the carbon number. Predicted molar flow rates of inorganic species, n-paraffins and total olefins were generally not in good agreement with the corresponding experimental values. In the future we'll use kinetic models based on non-constant value of {alpha}.

  3. Kinetics and mechanisms of reactions involving small aromatic reactive intermediates

    SciTech Connect (OSTI)

    Lin, M.C.

    1993-12-01

    Small aromatic radicals such as C{sub 6}H{sub 5}, C{sub 6}H{sub 5}O and C{sub 6}H{sub 4} are key prototype species of their homologs. C{sub 6}H{sub 5} and its oxidation product, C{sub 6}H{sub 5}O are believed to be important intermediates which play a pivotal role in hydrocarbon combustion, particularly with regard to soot formation. Despite their fundamental importance, experimental data on the reaction mechanisms and reactivities of these species are very limited. For C{sub 6}H{sub 5}, most kinetic data except its reactions with NO and NO{sub 2}, were obtained by relative rate measurements. For C{sub 6}H{sub 5}O, the authors have earlier measured its fragmentation reaction producing C{sub 5}H{sub 5} + CO in shock waves. For C{sub 6}H{sub 4}, the only rate constant measured in the gas phase is its recombination rate at room temperature. The authors have proposed to investigate systematically the kinetics and mechanisms of this important class of molecules using two parallel laser diagnostic techniques--laser resonance absorption (LRA) and resonance enhanced multiphoton ionization mass spectrometry (REMPI/MS). In the past two years, study has been focused on the development of a new multipass adsorption technique--the {open_quotes}cavity-ring-down{close_quotes} technique for kinetic applications. The preliminary results of this study appear to be quite good and the sensitivity of the technique is at least comparable to that of the laser-induced fluorescence method.

  4. Non-minimal Kinetic coupling to gravity and accelerated expansion

    SciTech Connect (OSTI)

    Granda, L.N.

    2010-07-01

    We study a scalar field with kinetic term coupled to itself and to the curvature, as a source of dark energy, and analyze the role of this new coupling in the accelerated expansion at large times. In the case of scalar field dominance, the scalar field and potential giving rise to power-law expansion are found in some cases, and a dynamical equation of state is calculated for a given solution of the field equations. A behavior very close to that of the cosmological constant was found.

  5. Thermodynamic and kinetic control of the lateral Si wire growth

    SciTech Connect (OSTI)

    Dedyulin, Sergey N. Goncharova, Lyudmila V.

    2014-03-24

    Reproducible lateral Si wire growth has been realized on the Si (100) surface. In this paper, we present experimental evidence showing the unique role that carbon plays in initiating lateral growth of Si wires on a Si (100) substrate. Once initiated in the presence of ?5 ML of C, lateral growth can be achieved in the range of temperatures, T?=?450650?C, and further controlled by the interplay of the flux of incoming Si atoms with the size and areal density of Au droplets. Critical thermodynamic and kinetic aspects of the growth are discussed in detail.

  6. Chemical Kinetics in Support of Syngas Turbine Combustion

    SciTech Connect (OSTI)

    Dryer, Frederick

    2007-07-31

    This document is the final report on an overall program formulated to extend our prior work in developing and validating kinetic models for the CO/hydrogen/oxygen reaction by carefully analyzing the individual and interactive behavior of specific elementary and subsets of elementary reactions at conditions of interest to syngas combustion in gas turbines. A summary of the tasks performed under this work are: 1. Determine experimentally the third body efficiencies in H+O{sub 2}+M = HO{sub 2}+M (R1) for CO{sub 2} and H{sub 2}O. 2. Using published literature data and the results in this program, further develop the present H{sub 2}/O{sub 2}/diluent and CO/H{sub 2}/O{sub 2}/diluent mechanisms for dilution with CO{sub 2}, H{sub 2}O and N{sub 2} through comparisons with new experimental validation targets for H{sub 2}-CO-O{sub 2}-N{sub 2} reaction kinetics in the presence of significant diluent fractions of CO{sub 2} and/or H{sub 2}O, at high pressures. (task amplified to especially address ignition delay issues, see below). 3. Analyze and demonstrate issues related to NOx interactions with syngas combustion chemistry (task amplified to include interactions of iron pentacarbonyl with syngas combustion chemistry, see below). 4. Publish results, including updated syngas kinetic model. Results are summarized in this document and its appendices. Three archival papers which contain a majority of the research results have appeared. Those results not published elsewhere are highlighted here, and will appear as part of future publications. Portions of the work appearing in the above publications were also supported in part by the Department of Energy under Grant No. DE-FG02-86ER-13503. As a result of and during the research under the present contract, we became aware of other reported results that revealed substantial differences between experimental characterizations of ignition delays for syngas mixtures and ignition delay predictions based upon homogenous kinetic modeling. We adjusted emphasis of Task 2 to understand the source of these noted disparities because of their key importance to developing lean premixed combustion technologies of syngas turbine applications. In performing Task 3, we also suggest for the first time the very significant effect that metal carbonyls may have on syngas combustion properties. This work is fully detailed. The work on metal carbonyl effects is entirely computational in nature. Pursuit of experimental verification of these interactions was beyond the scope of the present work.

  7. Evaluation of kinetic phosphorescence analysis for the determination of uranium

    SciTech Connect (OSTI)

    Croatto, P.V.; Frank, I.W.; Johnson, K.D.; Mason, P.B.; Smith, M.M.

    1997-12-01

    In the past, New Brunswick Laboratory (NBL) has used a fluorometric method for the determination of sub-microgram quantities of uranium. In its continuing effort to upgrade and improve measurement technology, NBL has evaluated the commercially-available KPA-11 kinetic phosphorescence analyzer (Chemchek, Richland, WA). The Chemchek KPA-11 is a bench-top instrument which performs single-measurement, quench-corrected analyses for trace uranium. It incorporates patented kinetic phosphorimetry techniques to measure and analyze sample phosphorescence as a function of time. With laser excitation and time-corrected photon counting, the KPA-11 has a lower detection limit than conventional fluorometric methods. Operated with a personal computer, the state-of-the-art KPA-11 offers extensive time resolution and phosphorescence lifetime capabilities for additional specificity. Interferences are thereby avoided while obtaining precise measurements. Routine analyses can be easily and effectively accomplished, with the accuracy and precision equivalent to the pulsed-laser fluorometric method presently performed at NBL, without the need for internal standards. Applications of kinetic phosphorimetry at NBL include the measurement of trace level uranium in retention tank, waste samples, and low-level samples. It has also been used to support other experimental activities at NBL by the measuring of nanogram amounts of uranium contamination (in blanks) in isotopic sample preparations, and the determining of elution curves of different ion exchange resins used for uranium purification. In many cases, no pretreatment of samples was necessary except to fume them with nitric acid, and then to redissolve and dilute them to an appropriate concentration with 1 M HNO{sub 3} before measurement. Concentrations were determined on a mass basis ({micro}g U/g of solution), but no density corrections were needed since all the samples (including the samples used for calibration) were in the same density matrix (1 M HNO{sub 3}). A statistical evaluation of the determination of uranium using kinetic phosphorimetry is described in this report, along with a discussion of the method, and an evaluation of the use of plastic versus quartz cuvettes. Measurement with a precision of {+-} 3--4% relative standard deviation (RSD) and an accuracy of better than {+-} 2% relative difference (RD) are obtained in the 0.0006 to 5 {micro}g U/g-solution range. The instrument detection limit is 0.04 ppb (4 x 10{sup {minus}5} {micro}g U/g solution) using quartz cells, and 0.11 ppb (11 x 10{sup {minus}5} {micro}g U/g solution) using disposable methacrylate cuvettes.

  8. Bio-butanol: Combustion properties and detailed chemical kinetic model

    SciTech Connect (OSTI)

    Black, G.; Curran, H.J.; Pichon, S.; Simmie, J.M.; Zhukov, V.

    2010-02-15

    Autoignition delay time measurements were performed at equivalence ratios of 0.5, 1 and 2 for butan-1-ol at reflected shock pressures of 1, 2.6 and 8 atm at temperatures from 1100 to 1800 K. High-level ab initio calculations were used to determine enthalpies of formation and consequently bond dissociation energies for each bond in the alcohol. A detailed chemical kinetic model consisting of 1399 reactions involving 234 species was constructed and tested against the delay times and also against recent jet-stirred reactor speciation data with encouraging results. The importance of enol chemistry is highlighted. (author)

  9. Convergent synthesis of proteins by kinetically controlled ligation

    DOE Patents [OSTI]

    Kent, Stephen; Pentelute, Brad; Bang, Duhee; Johnson, Erik; Durek, Thomas

    2010-03-09

    The present invention concerns methods and compositions for synthesizing a polypeptide using kinetically controlled reactions involving fragments of the polypeptide for a fully convergent process. In more specific embodiments, a ligation involves reacting a first peptide having a protected cysteyl group at its N-terminal and a phenylthioester at its C-terminal with a second peptide having a cysteine residue at its N-termini and a thioester at its C-termini to form a ligation product. Subsequent reactions may involve deprotecting the cysteyl group of the resulting ligation product and/or converting the thioester into a thiophenylester.

  10. Kinetics and deactivation of sulfated zirconia catalysts for butane isomerization

    SciTech Connect (OSTI)

    Fogash, K.B.; Larson, R.B.; Gonzalez, M.R.

    1996-09-15

    Reaction kinetics studies were conducted of n-butane and isobutane isomerization over sulfated zirconia at 423 K. The kinetic data can be described well by a rate expression based on a reversible, bimolecular surface reaction between two adsorbed n-C{sub 4} species, probably through a C{sub 8} intermediate, to produce one i-C{sub 4} species, as well as surface reaction between two adsorbed i-C{sub 4} species to produce one n-C{sub 4} species. This reaction sequence also describes well the rates of C{sub 4}-disproportionation reactions to produce C{sub 3} and C{sub 5} species. The initial rate of catalyst deactivation is faster during n-butane isomerization than during isobutane isomerization, and the longer-term rate of deactivation during n-butane isomerization increases with the pressures of n-butane. The more rapid catalyst deactivation during n-butane isomerization may be related to the formation of n-C{sub 4}-diene species. 25 refs., 10 figs., 4 tabs.

  11. Adding kinetics and hydrodynamics to the CHEETAH thermochemical code

    SciTech Connect (OSTI)

    Fried, L.E., Howard, W.M., Souers, P.C.

    1997-01-15

    In FY96 we released CHEETAH 1.40, which made extensive improvements on the stability and user friendliness of the code. CHEETAH now has over 175 users in government, academia, and industry. Efforts have also been focused on adding new advanced features to CHEETAH 2.0, which is scheduled for release in FY97. We have added a new chemical kinetics capability to CHEETAH. In the past, CHEETAH assumed complete thermodynamic equilibrium and independence of time. The addition of a chemical kinetic framework will allow for modeling of time-dependent phenomena, such as partial combustion and detonation in composite explosives with large reaction zones. We have implemented a Wood-Kirkwood detonation framework in CHEETAH, which allows for the treatment of nonideal detonations and explosive failure. A second major effort in the project this year has been linking CHEETAH to hydrodynamic codes to yield an improved HE product equation of state. We have linked CHEETAH to 1- and 2-D hydrodynamic codes, and have compared the code to experimental data. 15 refs., 13 figs., 1 tab.

  12. Solar kinetics` photovoltaic concentrator module and tracker development

    SciTech Connect (OSTI)

    White, D.L.; Howell, B. [Solar Kinetics, Inc., Dallas, TX (United States)

    1995-11-01

    Solar Kinetics, Inc., has been developing a point-focus concentrating photovoltaic module and tracker system under contract to Sandia National Laboratories. The primary focus of the contract was to achieve a module design that was manufacturable and passed Sandia`s environmental testing. Nine modules of two variations were assembled, tested, and characterized in Phase 1, and results of these tests were promising, with module efficiency approaching the theoretical limit achievable with the components used. The module efficiency was 11.9% at a solar irradiance of 850 W/m{sup 2} and an extrapolated cell temperature of 25{degrees}C. Improvements in module performance are anticipated as cell efficiencies meet their expectations. A 2-kW tracker and controller accommodating 20 modules was designed, built, installed, and operated at Solar Kinetics` test site. The drive used many commercially available components in an innovative arrangement to reduce cost and increase reliability. Backlash and bearing play were controlled by use of preloaded, low slip-stick, synthetic slide bearings. The controller design used a standard industrial programmable logic controller to perform ephemeris calculations, operate the actuators, and monitor encoders.

  13. Kinetic neoclassical transport in the H-mode pedestal

    SciTech Connect (OSTI)

    Battaglia, D. J.; Chang, C. S.; Ku, S.; Grierson, B. A.; Burrell, K. H.; Grassie, J. S. de

    2014-07-15

    Multi-species kinetic neoclassical transport through the QH-mode pedestal and scrape-off layer on DIII-D is calculated using XGC0, a 5D full-f particle-in-cell drift-kinetic solver with self-consistent neutral recycling and sheath potentials. Quantitative agreement between the flux-driven simulation and the experimental electron density, impurity density, and orthogonal measurements of impurity temperature and flow profiles is achieved by adding random-walk particle diffusion to the guiding-center drift motion. The radial electric field (E{sub r}) that maintains ambipolar transport across flux surfaces and to the wall is computed self-consistently on closed and open magnetic field lines and is in excellent agreement with experiment. The E{sub r} inside the separatrix is the unique solution that balances the outward flux of thermal tail deuterium ions against the outward neoclassical electron flux and inward pinch of impurity and colder deuterium ions. Particle transport in the pedestal is primarily due to anomalous transport, while the ion heat and momentum transport are primarily due to the neoclassical transport. The full-f treatment quantifies the non-Maxwellian energy distributions that describe a number of experimental observations in low-collisionallity pedestals on DIII-D, including intrinsic co-I{sub p} parallel flows in the pedestal, ion temperature anisotropy, and large impurity temperatures in the scrape-off layer.

  14. KINETIC MODELING OF FUEL EFFECTS OVER A WIDE RANGE OF CHEMISTRY,

    Office of Scientific and Technical Information (OSTI)

    PROPERTIES, AND SOURCES (Conference) | SciTech Connect KINETIC MODELING OF FUEL EFFECTS OVER A WIDE RANGE OF CHEMISTRY, PROPERTIES, AND SOURCES Citation Details In-Document Search Title: KINETIC MODELING OF FUEL EFFECTS OVER A WIDE RANGE OF CHEMISTRY, PROPERTIES, AND SOURCES Kinetic modeling is an important tool for engine design and can also be used for engine tuning and to study response to fuel chemistry and properties before an engine configuration is physically built and tested.

  15. Development of Kinetic Mechanisms for Next-Generation Fuels and CFD Simulation of Advanced Combustion Engines

    SciTech Connect (OSTI)

    Pitz, William J.; McNenly, Matt J.; Whitesides, Russell; Mehl, Marco; Killingsworth, Nick J.; Westbrook, Charles K.

    2015-12-17

    Predictive chemical kinetic models are needed to represent next-generation fuel components and their mixtures with conventional gasoline and diesel fuels. These kinetic models will allow the prediction of the effect of alternative fuel blends in CFD simulations of advanced spark-ignition and compression-ignition engines. Enabled by kinetic models, CFD simulations can be used to optimize fuel formulations for advanced combustion engines so that maximum engine efficiency, fossil fuel displacement goals, and low pollutant emission goals can be achieved.

  16. Chemical Kinetic Research on HCCI & Diesel Fuels | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    2 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting PDF icon ace013_pitz_2012_o.pdf More Documents & Publications Simulation of High Efficiency Clean Combustion Engines and Detailed Chemical Kinetic Mechanisms Development Chemical Kinetic Research on HCCI & Diesel Fuels Vehicle Technologies Office Merit Review 2014: Chemical Kinetic Models for Advanced Engine Combustion

  17. Chemical Kinetics Research on HCCI and Diesel Fuels | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    0 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. PDF icon ace013_pitz_2010_o.pdf More Documents & Publications Chemical Kinetics Research on HCCI and Diesel Fuels Chemical Kinetic Research on HCCI & Diesel Fuels Vehicle Technologies Office Merit Review 2014: Chemical Kinetic Models for Advanced Engine Combustion

    3 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review

  18. KineticsFinal Report Cover Page Bakajin, O 59 BASIC BIOLOGICAL...

    Office of Scientific and Technical Information (OSTI)

    KineticsFinal Report Cover Page Bakajin, O 59 BASIC BIOLOGICAL SCIENCES; 42 ENGINEERING; CONSUMPTION RATES; DEAD TIME; DETECTION; DIFFUSION; DNA; ENERGY TRANSFER; FABRICATION;...

  19. Photoelectrochemical etching of epitaxial InGaN thin films: kinetics...

    Office of Scientific and Technical Information (OSTI)

    films: kinetics and nanostructuring. Abstract not provided. Authors: Xiao, Xiaoyin ; Fischer, Arthur J. ; Coltrin, Michael E. ; Lu, Ping ; Koleske, Daniel ; Wang, George T. ;...

  20. Structure and Kinetic Analysis of H[subscript 2]S Production...

    Office of Scientific and Technical Information (OSTI)

    of Hsubscript 2S Production by Human Mercaptopyruvate Sulfurtransferase Citation Details In-Document Search Title: Structure and Kinetic Analysis of Hsubscript 2S ...

  1. Shaping the composition profiles in heteroepitaxial quantum dots: Interplay of thermodynamic and kinetic effects

    SciTech Connect (OSTI)

    Georgiou, C.; Leontiou, T.; Kelires, P. C.

    2014-07-15

    Atomistic Monte Carlo simulations, coupling thermodynamic and kinetic effects, resolve a longstanding controversy regarding the origin of composition profiles in heteroepitaxial SiGe quantum dots. It is shown that profiles with cores rich in the unstrained (Si) component derive from near-equilibrium processes and intraisland diffusion. Profiles with cores rich in the strained (Ge) component are of nonequilibrium nature, i.e., they are strain driven but kinetically limited. They are shaped by the distribution of kinetic barriers of atomic diffusion in the islands. The diffusion pathways are clearly revealed for the first time. Geometrical kinetics play a minor role.

  2. Gasdynamics in a coal seam. Part I: Mathematical description of the desorption kinetics

    SciTech Connect (OSTI)

    Kuznetsov, S.V.; Trofimov, V.A.

    2009-01-15

    The authors consider the gas desorption kinetics in the frame of a diffusion model, present alternative models and estimate their compatibility with the traditional.

  3. Hydrolysis of late-washed, irradiated tetraphenylborate slurry simulants I: Phenylboric acid hydrolysis kinetics

    SciTech Connect (OSTI)

    Marek, J.C.

    2000-02-10

    The attached report details the kinetics of phenylboric acid reaction at 90 degrees C during precipitate hydrolysis processing of late-washed, irradiated tetraphenylborate slurry simulants.

  4. Kinetics and Mechanisms of Calcite Reactions with Saline Waters

    SciTech Connect (OSTI)

    Gorman, Brian P

    2015-09-02

    Project Description: The general objective of the proposed research is to determine the kinetics and mechanisms of calcite reactions with saline waters over a wide range of saline water composition, pCO2, and modest ranges in T and P. This will be accomplished by studying both reaction rates and solubility from changes in solution chemistry, and making nanoscale observations of calcite precipitate surface morphology and composition at the micro-to-nano-scale to provide an understanding of controlling reaction mechanisms and pathways. The specific objectives necessary to reach the general objective are: a) determination of how pCO2, Ca2+, ionic strength and foreign ions influence reaction rates; and b) investigate the influence of these parameters on apparent kinetic solubility from dissolution and precipitation reactions. This information will clearly be central to the construction of reliable reaction-transport models to predict reservoir and formation response to increased CO2 in saline waters. This program was initially collaborative with John Morse at Texas A&M, however his passing shortly after the beginning of this program resulted in abbreviated research time and effort. Summary of Results: Early studies using electron microscopy and spectroscopy indicated that carbonate precipitation from natural seawater (NSW) conditions onto aragonite substrates was mediated by a surface amorphous calcium carbonate layer. It was hypothesized that this ACC layer (observed after < 5days reaction time) was responsible for the abnormal reaction kinetics and also served as a metastable seed layer for growth of epitaxial aragonite. Further studies of the ACC formation mechanism indicated a strong dependence on the Mg concentration in solution. Subsequent studies at shorter times (10 hrs) on calcite substrates and in a wide range of supersaturation conditions did not indicate any ACC layer. Instead, an epitaxial layer by layer growth mechanism was confirmed by grazing incidence X-ray diffraction, -Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and electron diffraction. Extended time studies out to 45 days confirmed the epitaxial relationship of the overgrowth layer with the substrate. Under NSW conditions, overgrowths were found to have ~0.4 to 0.8 nm / hr growth rates and accommodating 4 at% Mg, resulting in a highly strained overgrowth layer. Following the initial layer by layer growth mechanism, the growth changes to Stranski-Krastanov type after a critical thickness of approximately 100 nm.

  5. Isopiestic Kinetics of Powdered Pd/C/DPB Composite

    SciTech Connect (OSTI)

    Dinh, L; Saab, A

    2008-05-30

    In a 2006 LLNL internal report, a study of DEB and DPB based hydrogen getter materials was described. The materials, consisting of DEB or DPB physically blended with amorphous carbon on which palladium nanoparticle catalyst was supported, were studied during the course of reaction with fixed aliquots of hydrogen gas in order to observe their hydrogen consumption capacities as a function of ambient hydrogen pressure. The experiments demonstrated that the getter capacity was directly proportional to hydrogen fugacity: the lower the initial hydrogen pressure, the lower the resultant capacity at correspondingly low steady-state pressures. In the course of these experiments, further interesting observations were made of DEB and DPB reduction by hydrogen gas that painted a picture of a complicated reaction mechanism. To summarize, it was determined that reaction rate was controlled partly by diffusion of the organic diacetylene toward the catalyst surface. The results indicated this diffusion was in turn enhanced by phase changes in the course of the reaction that result in a liquid phase of the getter, and also by the heat of reaction, itself being proportional to initial reaction rate. However, these same two terms were speculated to have negative impacts on the net reaction kinetics, as well. It was suggested the liquid phase served to block gas access, and that excessively fast initial rates limited rate and capacity at later times by creating a depletion zone of reactant around the catalyst. Because of the nature of the experiments, whereby both hydrogen pressure and getter activity were changing in time, actual kinetic information could not be gathered. Knowledge of the reaction rate characteristics of these materials as a function of pressure and temperature is crucial to understanding the overall behavior of this material in service. Further, direct observation of the reaction rate can permit estimates of the diffusion of the reactive species. The present work centers on the development of an understanding of the kinetics for the hydrogenation of DPB and DEB as a function of temperature and pressure.

  6. An Experimental and Kinetic Modeling Study of Methyl Decanoate Combustion

    SciTech Connect (OSTI)

    Sarathy, S M; Thomson, M J; Pitz, W J; Lu, T

    2010-02-19

    Biodiesel is typically a mixture of long chain fatty acid methyl esters for use in compression ignition engines. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This research study presents new combustion data for methyl decanoate in an opposed-flow diffusion flame. An improved detailed chemical kinetic model for methyl decanoate combustion is developed, which serves as the basis for deriving a skeletal mechanism via the direct relation graph method. The novel skeletal mechanism consists of 648 species and 2998 reactions. This mechanism well predicts the methyl decanoate opposed-flow diffusion flame data. The results from the flame simulations indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene.

  7. An efficient method for unfolding kinetic pressure driven VISAR data

    SciTech Connect (OSTI)

    Mark Harry Hess; Peterson, Kyle; Harvey-Thompson, Adam James

    2015-08-18

    Velocity Interferometer System for Any Reflector (VISAR) [Barker and Hollenbach, J. Appl. Phys. 43, 4669 (1972)] is a well-known diagnostic that is employed on many shock physics and pulsed-power experiments. With the VISAR diagnostic, the velocity on the surface of any metal flyer can be found. For most experiments employing VISAR, either a kinetic pressure [Grady, Mech. Mater. 29, 181 (1998)] or a magnetic pressure [Lemke et al., Intl J. Impact Eng. 38, 480 (2011)] drives the motion of the flyer. Moreover, reliable prediction of the time-dependent pressure is often a critical component to understanding the physics of these experiments. Although VISAR can provide a precise measurement of a flyer’s surface velocity, the real challenge of this diagnostic implementation is using this velocity to unfold the time-dependent pressure. The purpose of this study is to elucidate a new method for quickly and reliably unfolding VISAR data.

  8. Chemical kinetic modeling of component mixtures relevant to gasoline

    SciTech Connect (OSTI)

    Mehl, M; Curran, H J; Pitz, W J; Westbrook, C K

    2009-02-13

    Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, a recently revised version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multi-component gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines. Simulation results are discussed focusing attention on the mixing effects of the fuel components.

  9. Temperature estimates from zircaloy oxidation kinetics and microstructures. [PWR

    SciTech Connect (OSTI)

    Olsen, C.S.

    1982-10-01

    This report reviews state-of-the-art capability to determine peak zircaloy fuel rod cladding temperatures following an abnormal temperature excursion in a nuclear reactor, based on postirradiation metallographic analysis of zircaloy microstructural and oxidation characteristics. Results of a comprehensive literature search are presented to evaluate the suitability of available zircaloy microstructural and oxidation data for estimating anticipated reactor fuel rod cladding temperatures. Additional oxidation experiments were conducted to evaluate low-temperature zircaloy oxidation characteristics for postirradiation estimation of cladding temperature by metallographic examination. Results of these experiments were used to calculate peak cladding temperatures of electrical heater rods and nuclear fuel rods that had been subjected to reactor temperature transients. Comparison of the calculated and measured peak cladding temperatures for these rods indicates that oxidation kinetics is a viable technique for estimating peak cladding temperatures over a broad temperature range. However, further improvement in zircaloy microstructure technology is necessary for precise estimation of peak cladding temperatures by microstructural examination.

  10. On the kinetic barriers of graphene homo-epitaxy

    SciTech Connect (OSTI)

    Zhang, Wei; Yu, Xinke; Xie, Ya-Hong; Cahyadi, Erica; Ratsch, Christian

    2014-12-01

    The diffusion processes and kinetic barriers of individual carbon adatoms and clusters on graphene surfaces are investigated to provide fundamental understanding of the physics governing epitaxial growth of multilayer graphene. It is found that individual carbon adatoms form bonds with the underlying graphene whereas the interaction between graphene and carbon clusters, consisting of 6 atoms or more, is very weak being van der Waals in nature. Therefore, small carbon clusters are quite mobile on the graphene surfaces and the diffusion barrier is negligibly small (?6?meV). This suggests the feasibility of high-quality graphene epitaxial growth at very low growth temperatures with small carbon clusters (e.g., hexagons) as carbon source. We propose that the growth mode is totally different from 3-dimensional bulk materials with the surface mobility of carbon hexagons being the highest over graphene surfaces that gradually decreases with further increase in cluster size.

  11. On the nature of kinetic electrostatic electron nonlinear (KEEN) waves

    SciTech Connect (OSTI)

    Dodin, I. Y.; Fisch, N. J.

    2014-03-15

    An analytical theory is proposed for the kinetic electrostatic electron nonlinear (KEEN) waves originally found in simulations by Afeyan et al. [arXiv:1210.8105]. We suggest that KEEN waves represent saturated states of the negative mass instability (NMI) reported recently by Dodin et al. [Phys. Rev. Lett. 110, 215006 (2013)]. Due to the NMI, trapped electrons form macroparticles that produce field oscillations at harmonics of the bounce frequency. At large enough amplitudes, these harmonics can phase-lock to the main wave and form stable nonlinear dissipationless structures that are nonstationary but otherwise similar to Bernstein-Greene-Kruskal modes. The theory explains why the formation of KEEN modes is sensitive to the excitation scenario and yields estimates that agree with the numerical results of Afeyan et al. A new type of KEEN wave may be possible at even larger amplitudes of the driving field than those used in simulations so far.

  12. Chemical Dynamics, Molecular Energetics, and Kinetics at the Synchrotron

    SciTech Connect (OSTI)

    Leone, Stephen R.; Ahmed, Musahid; Wilson, Kevin R.

    2010-03-14

    Scientists at the Chemical Dynamics Beamline of the Advanced Light Source in Berkeley are continuously reinventing synchrotron investigations of physical chemistry and chemical physics with vacuum ultraviolet light. One of the unique aspects of a synchrotron for chemical physics research is the widely tunable vacuum ultraviolet light that permits threshold ionization of large molecules with minimal fragmentation. This provides novel opportunities to assess molecular energetics and reaction mechanisms, even beyond simple gas phase molecules. In this perspective, significant new directions utilizing the capabilities at the Chemical Dynamics Beamline are presented, along with an outlook for future synchrotron and free electron laser science in chemical dynamics. Among the established and emerging fields of investigations are cluster and biological molecule spectroscopy and structure, combustion flame chemistry mechanisms, radical kinetics and product isomer dynamics, aerosol heterogeneous chemistry, planetary and interstellar chemistry, and secondary neutral ion-beam desorption imaging of biological matter and materials chemistry.

  13. High Temperature Chemical Kinetic Combustion Modeling of Lightly Methylated Alkanes

    SciTech Connect (OSTI)

    Sarathy, S M; Westbrook, C K; Pitz, W J; Mehl, M

    2011-03-01

    Conventional petroleum jet and diesel fuels, as well as alternative Fischer-Tropsch (FT) fuels and hydrotreated renewable jet (HRJ) fuels, contain high molecular weight lightly branched alkanes (i.e., methylalkanes) and straight chain alkanes (n-alkanes). Improving the combustion of these fuels in practical applications requires a fundamental understanding of large hydrocarbon combustion chemistry. This research project presents a detailed high temperature chemical kinetic mechanism for n-octane and three lightly branched isomers octane (i.e., 2-methylheptane, 3-methylheptane, and 2,5-dimethylhexane). The model is validated against experimental data from a variety of fundamental combustion devices. This new model is used to show how the location and number of methyl branches affects fuel reactivity including laminar flame speed and species formation.

  14. Q-branch Raman scattering and modern kinetic thoery

    SciTech Connect (OSTI)

    Monchick, L.

    1993-12-01

    The program is an extension of previous APL work whose general aim was to calculate line shapes of nearly resonant isolated line transitions with solutions of a popular quantum kinetic equation-the Waldmann-Snider equation-using well known advanced solution techniques developed for the classical Boltzmann equation. The advanced techniques explored have been a BGK type approximation, which is termed the Generalized Hess Method (GHM), and conversion of the collision operator to a block diagonal matrix of symmetric collision kernels which then can be approximated by discrete ordinate methods. The latter method, which is termed the Collision Kernel method (CC), is capable of the highest accuracy and has been used quite successfully for Q-branch Raman scattering. The GHM method, not quite as accurate, is applicable over a wider range of pressures and has proven quite useful.

  15. Chemical Kinetic Models for HCCI and Diesel Combustion

    SciTech Connect (OSTI)

    Pitz, W J; Westbook, C K; Mehl, M

    2008-10-30

    Hydrocarbon fuels for advanced combustion engines consist of complex mixtures of hundreds or even thousands of different components. These components can be grouped into a number of chemically distinct classes, consisting of n-paraffins, branched paraffins, cyclic paraffins, olefins, oxygenates, and aromatics. Biodiesel contains its own unique chemical class called methyl esters. The fractional amounts of these chemical classes are quite different in gasoline, diesel fuel, oil-sand derived fuels and bio-derived fuels, which contributes to the very different combustion characteristics of each of these types of combustion systems. The objectives of this project are: (1) Develop detailed chemical kinetic models for fuel components used in surrogate fuels for diesel and HCCI engines; (2) Develop surrogate fuel models to represent real fuels and model low temperature combustion strategies in HCCI and diesel engines that lead to low emissions and high efficiency; and (3) Characterize the role of fuel composition on low temperature combustion modes of advanced combustion engines.

  16. Mass independent kinetic energy reducing inlet system for vacuum environment

    DOE Patents [OSTI]

    Reilly, Peter T. A. [Knoxville, TN

    2010-12-14

    A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.

  17. Mass independent kinetic energy reducing inlet system for vacuum environment

    DOE Patents [OSTI]

    Reilly, Peter T.A.

    2014-05-13

    A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.

  18. Mass independent kinetic energy reducing inlet system for vacuum environment

    DOE Patents [OSTI]

    Reilly, Peter T.A.

    2013-12-03

    A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.

  19. Alkaline assisted thermal oil recovery: Kinetic and displacement studies

    SciTech Connect (OSTI)

    Saneie, S.; Yortsos, Y.C.

    1993-06-01

    This report deals with two major issues of chemical assisted flooding - the interaction of caustic, one of the proposed additives to steam flood, with the reservoir rock, and the displacement of oil by a chemical flood at elevated temperatures. A mathematical model simulating the kinetics of silica dissolution and hydroxyl ion consumption in a typical alkaline flooding environment is first developed. The model is based on the premise that dissolution occurs via hydrolysis of active sites through the formation of an intermediate complex, which is in equilibrium with the silicic acid in solution. Both static (batch) and dynamic (core flood) processes are simulated to examine the sensitivity of caustic consumption and silica dissolution to process parameters, and to determine rates of propagation of pH values. The model presented provides a quantitative description of the quartz-alkali interaction in terms of pH, salinity, ion exchange properties, temperature and contact time, which are of significant importance in the design of soluble silicate flooding processes. The modeling of an adiabatic hot waterflood assisted by the simultaneous injection of a chemical additive is next presented. The model is also applicable to the hot alkaline flooding under conditions of negligible adsorption of the generated anionic surfactant and of hydroxide adsorption being Langmuirian. The theory of generalized simple waves (coherence ) is used to develop solutions for the temperature, concentration, and oil saturation profiles, as well as the oil recovery curves. It is shown that, for Langmuir adsorption kinetics, the chemical resides in the heated region of the reservoir if its injection concentration is below a critical value, and in the unheated region if its concentration exceeds this critical value. Results for a chemical slug injection in a tertiary recovery process indicate recovery performance is maximized when chemical resides in the heated region of the reservior.

  20. Parameter estimation for models of ligninolytic and cellulolytic enzyme kinetics

    SciTech Connect (OSTI)

    Wang, Gangsheng; Post, Wilfred M; Mayes, Melanie; Frerichs, Joshua T; Jagadamma, Sindhu

    2012-01-01

    While soil enzymes have been explicitly included in the soil organic carbon (SOC) decomposition models, there is a serious lack of suitable data for model parameterization. This study provides well-documented enzymatic parameters for application in enzyme-driven SOC decomposition models from a compilation and analysis of published measurements. In particular, we developed appropriate kinetic parameters for five typical ligninolytic and cellulolytic enzymes ( -glucosidase, cellobiohydrolase, endo-glucanase, peroxidase, and phenol oxidase). The kinetic parameters included the maximum specific enzyme activity (Vmax) and half-saturation constant (Km) in the Michaelis-Menten equation. The activation energy (Ea) and the pH optimum and sensitivity (pHopt and pHsen) were also analyzed. pHsen was estimated by fitting an exponential-quadratic function. The Vmax values, often presented in different units under various measurement conditions, were converted into the same units at a reference temperature (20 C) and pHopt. Major conclusions are: (i) Both Vmax and Km were log-normal distributed, with no significant difference in Vmax exhibited between enzymes originating from bacteria or fungi. (ii) No significant difference in Vmax was found between cellulases and ligninases; however, there was significant difference in Km between them. (iii) Ligninases had higher Ea values and lower pHopt than cellulases; average ratio of pHsen to pHopt ranged 0.3 0.4 for the five enzymes, which means that an increase or decrease of 1.1 1.7 pH units from pHopt would reduce Vmax by 50%. (iv) Our analysis indicated that the Vmax values from lab measurements with purified enzymes were 1 2 orders of magnitude higher than those for use in SOC decomposition models under field conditions.

  1. Energy dynamics and current sheet structure in fluid and kinetic simulations of decaying magnetohydrodynamic turbulence

    SciTech Connect (OSTI)

    Makwana, K. D. Cattaneo, F.; Zhdankin, V.; Li, H.; Daughton, W.

    2015-04-15

    Simulations of decaying magnetohydrodynamic (MHD) turbulence are performed with a fluid and a kinetic code. The initial condition is an ensemble of long-wavelength, counter-propagating, shear-Alfvén waves, which interact and rapidly generate strong MHD turbulence. The total energy is conserved and the rate of turbulent energy decay is very similar in both codes, although the fluid code has numerical dissipation, whereas the kinetic code has kinetic dissipation. The inertial range power spectrum index is similar in both the codes. The fluid code shows a perpendicular wavenumber spectral slope of k{sub ⊥}{sup −1.3}. The kinetic code shows a spectral slope of k{sub ⊥}{sup −1.5} for smaller simulation domain, and k{sub ⊥}{sup −1.3} for larger domain. We estimate that collisionless damping mechanisms in the kinetic code can account for the dissipation of the observed nonlinear energy cascade. Current sheets are geometrically characterized. Their lengths and widths are in good agreement between the two codes. The length scales linearly with the driving scale of the turbulence. In the fluid code, their thickness is determined by the grid resolution as there is no explicit diffusivity. In the kinetic code, their thickness is very close to the skin-depth, irrespective of the grid resolution. This work shows that kinetic codes can reproduce the MHD inertial range dynamics at large scales, while at the same time capturing important kinetic physics at small scales.

  2. CHEMKIN-III: A FORTRAN chemical kinetics package for the analysis of gas-phase chemical and plasma kinetics

    SciTech Connect (OSTI)

    Kee, R.J.; Rupley, F.M.; Meeks, E.; Miller, J.A.

    1996-05-01

    This document is the user`s manual for the third-generation CHEMKIN package. CHEMKIN is a software package whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provides a flexible and powerful tool for incorporating complex chemical kinetics into simulations of fluid dynamics. The package consists of two major software components: an Interpreter and a Gas-Phase Subroutine Library. The Interpreter is a program that reads a symbolic description of an elementary, user-specified chemical reaction mechanism. One output from the Interpreter is a data file that forms a link to the Gas-Phase Subroutine Library. This library is a collection of about 100 highly modular FORTRAN subroutines that may be called to return information on equations of state, thermodynamic properties, and chemical production rates. CHEMKIN-III includes capabilities for treating multi-fluid plasma systems, that are not in thermal equilibrium. These new capabilities allow researchers to describe chemistry systems that are characterized by more than one temperature, in which reactions may depend on temperatures associated with different species; i.e. reactions may be driven by collisions with electrons, ions, or charge-neutral species. These new features have been implemented in such a way as to require little or no changes to CHEMKIN implementation for systems in thermal equilibrium, where all species share the same gas temperature. CHEMKIN-III now has the capability to handle weakly ionized plasma chemistry, especially for application related to advanced semiconductor processing.

  3. Pattern Formation and Growth Kinetics in Eutectic Systems

    SciTech Connect (OSTI)

    Jing Teng

    2007-12-01

    Growth patterns during liquid/solid phase transformation are governed by simultaneous effects of heat and mass transfer mechanisms, creation of new interfaces, jump of the crystallization units from liquid to solid and their rearrangement in the solid matrix. To examine how the above processes influence the scale of microstructure, two eutectic systems are chosen for the study: a polymeric system polyethylene glycol-p-dibromobenzene (PEG-DBBZ) and a simple molecular system succinonitrile (SCN)-camphor. The scaling law for SCN-camphor system is found to follow the classical Jackson-Hunt model of circular rod eutectic, where the diffusion in the liquid and the interface energy are the main physics governing the two-phase pattern. In contrast, a significantly different scaling law is observed for the polymer system. The interface kinetics of PEG phase and its solute concentration dependence thus have been critically investigated for the first time by directional solidification technique. A model is then proposed that shows that the two-phase pattern in polymers is governed by the interface diffusion and the interface kinetics. In SCN-camphor system, a new branch of eutectic, elliptical shape rodl, is found in thin samples where only one layer of camphor rods is present. It is found that the orientation of the ellipse can change from the major axis in the direction of the thickness to the direction of the width as the velocity and/or the sample thickness is decreased. A theoretical model is developed that predicts the spacing and orientation of the elliptical rods in a thin sample. The single phase growth patterns of SCN-camphor system were also examined with emphasis on the three-dimensional single cell and cell/dendrite transition. For the 3D single cell in a capillary tube, the entire cell shape ahead of the eutectic front can be described by the Saffmann-Taylor finger only at extremely low growth rate. A 3D directional solidification model is developed to characterize the cell shape and tip undercooling and the experimental results are compared with the predictions of the model. From the investigation of cell/dendrite transition, a model is proposed, from which the condition for the onset of the transition can be obtained.

  4. A Comparison of HCCI Engine Performance Data and Kinetic Modeling Results over a Wide Rangeof Gasoline Range Surrogate Fuel Blends

    Broader source: Energy.gov [DOE]

    Kinetic models of fuels are needed to allow the simulation of engine performance for research, design, or verification purposes.

  5. Kinetic Modeling of Combustion Characteristics of Real Biodiesel Fuels

    SciTech Connect (OSTI)

    Naik, C V; Westbrook, C K

    2009-04-08

    Biodiesel fuels are of much interest today either for replacing or blending with conventional fuels for automotive applications. Predicting engine effects of using biodiesel fuel requires accurate understanding of the combustion characteristics of the fuel, which can be acquired through analysis using reliable detailed reaction mechanisms. Unlike gasoline or diesel that consists of hundreds of chemical compounds, biodiesel fuels contain only a limited number of compounds. Over 90% of the biodiesel fraction is composed of 5 unique long-chain C{sub 18} and C{sub 16} saturated and unsaturated methyl esters. This makes modeling of real biodiesel fuel possible without the need for a fuel surrogate. To this end, a detailed chemical kinetic mechanism has been developed for determining the combustion characteristics of a pure biodiesel (B100) fuel, applicable from low- to high-temperature oxidation regimes. This model has been built based on reaction rate rules established in previous studies at Lawrence Livermore National Laboratory. Computed results are compared with the few fundamental experimental data that exist for biodiesel fuel and its components. In addition, computed results have been compared with experimental data for other long-chain hydrocarbons that are similar in structure to the biodiesel components.

  6. Modeling Momentum Transfer from Kinetic Impacts: Implications for Redirecting Asteroids

    SciTech Connect (OSTI)

    Stickle, A. M.; Atchison, J. A.; Barnouin, O. S.; Cheng, A. F.; Crawford, D. A.; Ernst, C. M.; Fletcher, Z.; Rivkin, A. S.

    2015-05-19

    Kinetic impactors are one way to deflect a potentially hazardous object headed for Earth. The Asteroid Impact and Deflection Assessment (AIDA) mission is designed to test the effectiveness of this approach and is a joint effort between NASA and ESA. The NASA-led portion is the Double Asteroid Redirect Test (DART) and is composed of a ~300-kg spacecraft designed to impact the moon of the binary system 65803 Didymos. The deflection of the moon will be measured by the ESA-led Asteroid Impact Mission (AIM) (which will characterize the moon) and from ground-based observations. Because the material properties and internal structure of the target are poorly constrained, however, analytical models and numerical simulations must be used to understand the range of potential outcomes. Here, we describe a modeling effort combining analytical models and CTH simulations to determine possible outcomes of the DART impact. We examine a wide parameter space and provide predictions for crater size, ejecta mass, and momentum transfer following the impact into the moon of the Didymos system. For impacts into “realistic” asteroid types, these models produce craters with diameters on the order of 10 m, an imparted Δv of 0.5–2 mm/s and a momentum enhancement of 1.07 to 5 for a highly porous aggregate to a fully dense rock.

  7. Mechanism and kinetics of peptide partitioning into membranes

    SciTech Connect (OSTI)

    Ulmschneider, Martin [University of Oxford; Killian, J Antoinette [University of Utrecht; Doux, Jacques P. F. [University of Utrecht; Smith, Jeremy C [ORNL; Ulmschneider, Jakob [University of Heidelberg

    2010-02-01

    Partitioning properties of transmembrane (TM) polypeptide segments directly determine membrane protein folding, stability, and function, and their understanding is vital for rational design of membrane active peptides. However, direct determination of water-to-bilayer transfer of TM peptides has proved difficult. Experimentally, sufficiently hydrophobic peptides tend to aggregate, while atomistic computer simulations at physiological temperatures cannot yet reach the long time scales required to capture partitioning. Elevating temperatures to accelerate the dynamics has been avoided, as this was thought to lead to rapid denaturing. However, we show here that model TM peptides (WALP) are exceptionally thermostable. Circular dichroism experiments reveal that the peptides remain inserted into the lipid bilayer and are fully helical, even at 90 C. At these temperatures, sampling is 50 500 times faster, sufficient to directly simulate spontaneous partitioning at atomic resolution. A folded insertion pathway is observed, consistent with three-stage partitioning theory. Elevated temperature simulation ensembles further allow the direct calculation of the insertion kinetics, which is found to be first-order for all systems. Insertion barriers are Hin = 15 kcal/mol for a general hydrophobic peptide and 23 kcal/mol for the tryptophan-flanked WALP peptides. The corresponding insertion times at room temperature range from 8.5 s to 163 ms. High-temperature simulations of experimentally validated thermostable systems suggest a new avenue for systematic exploration of peptide partitioning properties.

  8. An efficient method for unfolding kinetic pressure driven VISAR data

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mark Harry Hess; Peterson, Kyle; Harvey-Thompson, Adam James

    2015-08-18

    Velocity Interferometer System for Any Reflector (VISAR) [Barker and Hollenbach, J. Appl. Phys. 43, 4669 (1972)] is a well-known diagnostic that is employed on many shock physics and pulsed-power experiments. With the VISAR diagnostic, the velocity on the surface of any metal flyer can be found. For most experiments employing VISAR, either a kinetic pressure [Grady, Mech. Mater. 29, 181 (1998)] or a magnetic pressure [Lemke et al., Intl J. Impact Eng. 38, 480 (2011)] drives the motion of the flyer. Moreover, reliable prediction of the time-dependent pressure is often a critical component to understanding the physics of these experiments.more » Although VISAR can provide a precise measurement of a flyer’s surface velocity, the real challenge of this diagnostic implementation is using this velocity to unfold the time-dependent pressure. The purpose of this study is to elucidate a new method for quickly and reliably unfolding VISAR data.« less

  9. Oxidation kinetics of calcium-doped palladium powders

    SciTech Connect (OSTI)

    Jain, S.; Kodas, T.T.; Hampden-Smith, M. [Univ. of New Mexico, Albuquerque, NM (United States)

    1997-04-01

    The oxidation kinetics of submicron Ca-containing Pd powders produced by spray pyrolysis were studied in the temperature range 600 to 675 C using thermogravimetric analysis. The oxidation of pure Pd powder had an activation energy of {approximately}230 kJ/mol in the region 27% < oxidation < 70% and 65 kJ/mol for oxidation > 70%. The activation energies for Pd particles containing 0.01 weight percent (w/o) and 0.4 w/o Ca in the region 27% < oxidation < 70% were {approximately}230 kJ/mol and {approximately}50 kJ/mol, respectively. Transmission electron microscopy suggested that the conversion of Pd to Pd{sup II}O (stoichiometric PdO) proceeds from the particle surface into the interior and not homogeneously throughout the particle. The predictions of a variety of models and rate laws (shrinking core, parabolic, cubic, logarithmic, and inverse logarithmic) were compared with the data. The comparison suggested a mechanism in which oxidation of pure Pd proceeds by chemisorption and diffusion of oxygen to form a substoichiometric oxide, followed by the conversion of substoichiometric PdO to Pd{sup II}O. Oxidation of pure Pd is then probably limited by the diffusion of oxygen through the substoichiometric PdO and/or Pd{sup II}O. The addition of Ca increased the oxidation resistance of Pd most likely by inhibiting oxygen diffusion through the metal oxide layers surrounding the Pd.

  10. Utilization of Kinetic Isotope Effects for the Concentration of Tritium

    SciTech Connect (OSTI)

    Brown, Gilbert M.; Meyer, Thomas J.; Moyer, Bruce A.

    2000-06-01

    Work is in progress to develop methods for concentrating tritium in water based on large primary isotope effects in catalytic redox processes. Basic research is being conducted to develop the chemistry of a complete cyclic process. The process will remove tritium from H2O by concentrating it with respect to protio-water. This research involves developing chemical cycles that produce high concentration factors for HTO based on the discrimination of CH and C-T bonds in oxidation reactions. Several steps are required in a cyclic process for the concentration of tritium in water. In the first step, the tritium is incorporated in an organic compound. H-T discrimination occurs as the tritium containing compound is oxidized in a step involving a Ru(IV) oxo complex. Strong primary kinetic isotope effects lead to the oxidation of C-H bonds in preference to C-T bonds, and this reaction leads to concentration of tritium in the organic compound. The reduced form of the ruthenium compound can be reoxidized so that the oxidation step can be made catalytic.

  11. KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYNTHESIS

    SciTech Connect (OSTI)

    Dragomir B. Bukur

    2004-09-29

    This report covers the second year of this three-year research grant under the University Coal Research program. The overall objective of this project is to develop a comprehensive kinetic model for slurry phase Fischer-Tropsch synthesis on iron catalysts. This model will be validated with experimental data obtained in a stirred tank slurry reactor (STSR) over a wide range of process conditions. The model will be able to predict concentrations of all reactants and major product species (H{sub 2}O, CO{sub 2}, linear 1- and 2-olefins, and linear paraffins) as a function of reaction conditions in the STSR. During the second year of the project we completed the STSR test SB-26203 (275-343 h on stream), which was initiated during the first year of the project, and another STSR test (SB-28603 lasting 341 h). Since the inception of the project we completed 3 STSR tests, and evaluated catalyst under 25 different sets of process conditions. A precipitated iron catalyst obtained from Ruhrchemie AG (Oberhausen-Holten, Germany) was used in all tests. This catalyst was used initially in commercial fixed bed reactors at Sasol in South Africa. Also, during the second year we performed a qualitative analysis of experimental data from all three STSR tests. Effects of process conditions (reaction temperature, pressure, feed composition and gas space velocity) on water-gas-shift (WGS) activity and hydrocarbon product distribution have been determined.

  12. KINETICS OF SLURRY PHASE FISCHER-TROPSCH SYNTHESIS

    SciTech Connect (OSTI)

    Dragomir B. Bukur; Gilbert F. Froment; Lech Nowicki; Jiang Wang; Wen-Ping Ma

    2003-09-29

    This report covers the first year of this three-year research grant under the University Coal Research program. The overall objective of this project is to develop a comprehensive kinetic model for slurry phase Fischer-Tropsch synthesis on iron catalysts. This model will be validated with experimental data obtained in a stirred tank slurry reactor (STSR) over a wide range of process conditions. The model will be able to predict concentrations of all reactants and major product species (H{sup 2}O, CO{sub 2}, linear 1- and 2-olefins, and linear paraffins) as a function of reaction conditions in the STSR. During the reporting period we have completed one STSR test with precipitated iron catalyst obtained from Ruhrchemie AG (Oberhausen-Holten, Germany). This catalyst was initially in commercial fixed bed reactors at Sasol in South Africa. The catalyst was tested at 13 different sets of process conditions, and had experienced a moderate deactivation during the first 500 h of testing (decrease in conversion from 56% to 50% at baseline process conditions). The second STSR test has been initiated and after 270 h on stream, the catalyst was tested at 6 different sets of process conditions.

  13. Modeling Momentum Transfer from Kinetic Impacts: Implications for Redirecting Asteroids

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Stickle, A. M.; Atchison, J. A.; Barnouin, O. S.; Cheng, A. F.; Crawford, D. A.; Ernst, C. M.; Fletcher, Z.; Rivkin, A. S.

    2015-05-19

    Kinetic impactors are one way to deflect a potentially hazardous object headed for Earth. The Asteroid Impact and Deflection Assessment (AIDA) mission is designed to test the effectiveness of this approach and is a joint effort between NASA and ESA. The NASA-led portion is the Double Asteroid Redirect Test (DART) and is composed of a ~300-kg spacecraft designed to impact the moon of the binary system 65803 Didymos. The deflection of the moon will be measured by the ESA-led Asteroid Impact Mission (AIM) (which will characterize the moon) and from ground-based observations. Because the material properties and internal structure ofmore » the target are poorly constrained, however, analytical models and numerical simulations must be used to understand the range of potential outcomes. Here, we describe a modeling effort combining analytical models and CTH simulations to determine possible outcomes of the DART impact. We examine a wide parameter space and provide predictions for crater size, ejecta mass, and momentum transfer following the impact into the moon of the Didymos system. For impacts into “realistic” asteroid types, these models produce craters with diameters on the order of 10 m, an imparted Δv of 0.5–2 mm/s and a momentum enhancement of 1.07 to 5 for a highly porous aggregate to a fully dense rock.« less

  14. Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels

    SciTech Connect (OSTI)

    Peterson, Eric; Krejci, Michael; Mathieu, Olivier; Vissotski, Andrew; Ravi, Sankat; Plichta, Drew; Sikes, Travis; Levacque, Anthony; Camou, Alejandro; Aul, Christopher

    2013-09-30

    This final report documents the technical results of the 3-year project entitled, “Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels,” funded under the NETL of DOE. The research was conducted under six main tasks: 1) program management and planning; 2) turbulent flame speed measurements of syngas mixtures; 3) laminar flame speed measurements with diluents; 4) NOx mechanism validation experiments; 5) fundamental NOx kinetics; and 6) the effect of impurities on NOx kinetics. Experiments were performed using primary constant-volume vessels for laminar and turbulent flame speeds and shock tubes for ignition delay times and species concentrations. In addition to the existing shock- tube and flame speed facilities, a new capability in measuring turbulent flame speeds was developed under this grant. Other highlights include an improved NOx kinetics mechanism; a database on syngas blends for real fuel mixtures with and without impurities; an improved hydrogen sulfide mechanism; an improved ammonia kintics mechanism; laminar flame speed data at high pressures with water addition; and the development of an inexpensive absorption spectroscopy diagnostic for shock-tube measurements of OH time histories. The Project Results for this work can be divided into 13 major sections, which form the basis of this report. These 13 topics are divided into the five areas: 1) laminar flame speeds; 2) Nitrogen Oxide and Ammonia chemical kinetics; 3) syngas impurities chemical kinetics; 4) turbulent flame speeds; and 5) OH absorption measurements for chemical kinetics.

  15. Empirical and physics based mathematical models of uranium hydride decomposition kinetics with quantified uncertainties.

    SciTech Connect (OSTI)

    Salloum, Maher N.; Gharagozloo, Patricia E.

    2013-10-01

    Metal particle beds have recently become a major technique for hydrogen storage. In order to extract hydrogen from such beds, it is crucial to understand the decomposition kinetics of the metal hydride. We are interested in obtaining a a better understanding of the uranium hydride (UH3) decomposition kinetics. We first developed an empirical model by fitting data compiled from different experimental studies in the literature and quantified the uncertainty resulting from the scattered data. We found that the decomposition time range predicted by the obtained kinetics was in a good agreement with published experimental results. Secondly, we developed a physics based mathematical model to simulate the rate of hydrogen diffusion in a hydride particle during the decomposition. We used this model to simulate the decomposition of the particles for temperatures ranging from 300K to 1000K while propagating parametric uncertainty and evaluated the kinetics from the results. We compared the kinetics parameters derived from the empirical and physics based models and found that the uncertainty in the kinetics predicted by the physics based model covers the scattered experimental data. Finally, we used the physics-based kinetics parameters to simulate the effects of boundary resistances and powder morphological changes during decomposition in a continuum level model. We found that the species change within the bed occurring during the decomposition accelerates the hydrogen flow by increasing the bed permeability, while the pressure buildup and the thermal barrier forming at the wall significantly impede the hydrogen extraction.

  16. Kinetics of trans-cis isomerization in azobenzene dimers at an air-water interface

    SciTech Connect (OSTI)

    Kumar, Bharat; Suresh, K. A.

    2009-08-15

    We have studied the kinetics of trans to cis isomerization under the illumination of ultraviolet light, in the Langmuir monolayer of mesogenic azobenzene dimer, bis-[5-(4{sup '}-n-dodecyloxy benzoyloxy)-2-(4{sup ''}-methylphenylazo)phenyl] adipate, at an air-water interface. We find that the trans to cis isomerization reaction of the molecules in the monolayer shows deviation from the first-order kinetics unlike those reported on Langmuir monolayers of azobenzene molecules. We attribute the deviation from first-order kinetics to the simultaneous photoisomerization of trans isomers to form cis isomers and the reverse thermal isomerization of cis isomers to form trans isomers. Our analysis of the rate of change of mole fraction of trans isomers to form cis isomers indicates a first-order kinetics for trans to cis photoisomerization reaction and a second-order kinetics for cis to trans thermal isomerization reaction. This second-order kinetics mechanism is similar to the Lindemann-Hinshelwood mechanism for the unimolecular reactions at low concentration of reactants. The formation of the activated cis isomer by collisions is a slow process as compared to the decay of the activated cis isomer to trans isomer in the liquid expanded phase. This results in the second-order kinetics for the thermal isomerization of cis isomers.

  17. Reduced and Validated Kinetic Mechanisms for Hydrogen-CO-sir Combustion in Gas Turbines

    SciTech Connect (OSTI)

    Yiguang Ju; Frederick Dryer

    2009-02-07

    Rigorous experimental, theoretical, and numerical investigation of various issues relevant to the development of reduced, validated kinetic mechanisms for synthetic gas combustion in gas turbines was carried out - including the construction of new radiation models for combusting flows, improvement of flame speed measurement techniques, measurements and chemical kinetic analysis of H{sub 2}/CO/CO{sub 2}/O{sub 2}/diluent mixtures, revision of the H{sub 2}/O{sub 2} kinetic model to improve flame speed prediction capabilities, and development of a multi-time scale algorithm to improve computational efficiency in reacting flow simulations.

  18. Simulation of atomic diffusion in the Fcc NiAl system: A kinetic Monte

    Office of Scientific and Technical Information (OSTI)

    Carlo study (Journal Article) | SciTech Connect Journal Article: Simulation of atomic diffusion in the Fcc NiAl system: A kinetic Monte Carlo study Citation Details In-Document Search Title: Simulation of atomic diffusion in the Fcc NiAl system: A kinetic Monte Carlo study The atomic diffusion in fcc NiAl binary alloys was studied by kinetic Monte Carlo simulation. The environment dependent hopping barriers were computed using a pair interaction model whose parameters were fitted to relevant

  19. Dechlorination of polychlorinated biphenyls: A kinetic study of removal of PCBs from mineral oils

    SciTech Connect (OSTI)

    Filippis, P. de; Scarsella, M.; Pochetti, F.

    1999-02-01

    A kinetic study was done of the dechlorination of polychlorinated biphenyls (PCBs) eliminated from contaminated dielectric oils by using the potassium poly(ethylene glycolate) (KPEG) process. Experimental runs at laboratory scale showed that the kinetics of the removal reaction was first-order for each PCB present and first-order with respect to the KPEG concentration. The PCB elimination grade was also affected by the KOH/PEG ratio. An exponential correlation was found between the kinetic constant for each congener and its respective gas chromatographic relative retention time.

  20. Chemical kinetic modeling of component mixtures relevant to gasoline

    SciTech Connect (OSTI)

    Mehl, M; Curran, H J; Pitz, W J; Dooley, S; Westbrook, C K

    2008-05-29

    Detailed kinetic models of pyrolysis and combustion of hydrocarbon fuels are nowadays widely used in the design of internal combustion engines and these models are effectively applied to help meet the increasingly stringent environmental and energetic standards. In previous studies by the combustion community, such models not only contributed to the understanding of pure component combustion, but also provided a deeper insight into the combustion behavior of complex mixtures. One of the major challenges in this field is now the definition and the development of appropriate surrogate models able to mimic the actual features of real fuels. Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. Their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. Aside the most commonly used surrogates containing iso-octane and n-heptane only, the so called Primary Reference Fuels (PRF), new mixtures have recently been suggested to extend the reference components in surrogate mixtures to also include alkenes and aromatics. It is generally agreed that, including representative species for all the main classes of hydrocarbons which can be found in real fuels, it is possible to reproduce very effectively in a wide range of operating conditions not just the auto-ignition propensity of gasoline or Diesel fuels, but also their physical properties and their combustion residuals [1]. In this work, the combustion behavior of several components relevant to gasoline surrogate formulation is computationally examined. The attention is focused on the autoignition of iso-octane, hexene and their mixtures. Some important issues relevant to the experimental and modeling investigation of such fuels are discussed with the help of rapid compression machine data and calculations. Following the model validation, the behavior of mixtures is discussed on the basis of computational results.

  1. Kinetic extensions of magnetohydrodynamic models for axisymmetric toroidal plasmas

    SciTech Connect (OSTI)

    Cheng, C.Z.

    1989-04-01

    A nonvariational kinetic-MHD stability code (NOVA-K) has been developed to integrate a set of non-Hermitian integro-differential eigenmode equations due to energetic particles for axisymmetric toroidal plasmas in a general flux coordinate system with an arbitrary Jacobian. The NOVA-K code employs the Galerkin method involving Fourier expansions in the generalized poloidal angle theta and generalized toroidal angle /zeta/ directions, and cubic-B spline finite elements in the radial /Psi/ direction. Extensive comparisons with the existing variational ideal MHD codes show that the ideal MHD version of the NOVA-K code converges faster and gives more accurate results. The NOVA-K code is employed to study the effects of energetic particles on MHD-type modes: the stabilization of ideal MHD internal kink modes and the excitation of ''fishbone'' internal kink modes; and the alpha particle destabilization of toroidicity-induced Alfven eigenmodes (TAE) via transit resonances. Analytical theories are also presented to help explain the NOVA-K results. For energetic trapped particles generated by neutral beam injection (NBI) or ion cyclotron resonant heating (ICRH), a stability window for the n = 1 internal kink mode in the hot particle beta space exists even in the absence of the core ion finite Larmor radius effect. On the other hand, the trapped alpha particles are found to have negligible effects on the stability of the n = 1 internal kink mode, but the circulating alpha particles can strongly destabilize TAE modes via inverse Landau damping associated with the spatial gradient of the alpha particle pressure. 60 refs., 24 figs., 1 tab.

  2. Utilization of Kinetic Isotope Effects for the Concentration of Tritium

    SciTech Connect (OSTI)

    Brown, Gilbert M.; Meyer, Thomas j.; Moyer, Bruce A.

    1999-06-01

    The objective of this research program is to develop methods for concentrating tritium in water based on large primary isotope effects in catalytic redox processes. Basic research is being conducted to develop the chemistry of a complete cyclic process. Because tritium (generally present as HTO) is in a rapidly established equilibrium with protio-water, it moves with groundwater and separation from water cannot be achieved by the usual pump-and-treat methods using sorbants. The general methodology developed in this work will be applicable to a number of DOE waste streams, and as a consequence of the process tritium will be incorporated into an organic compound that will not readily exchange the tritium with groundwater. The process to be developed will remove tritium from H2O by concentrating it with respect to protio-water. This research involves developing chemical cycles that produce high concentration factors for HTO and T2O based on the discrimination of C-H and C-T bonds in oxidation reactions. Several steps are required in a cyclic process for the concentration of tritium in water. In the first step the tritium is incorporated in an organic compound. H-T discrimination occurs as the tritium containing compound is oxidized in a step involving a Ru(IV) oxo complex. Strong primary kinetic isotope effects lead to the oxidation of C-H bonds in preference to C-T bonds, and this reaction leads to concentration of tritium in the organic compound. The reduced form of the ruthenium compound can be reoxidized so that the oxidation step can be made catalytic.

  3. Weakly Ionized Plasmas in Hypersonics: Fundamental Kinetics and Flight Applications

    SciTech Connect (OSTI)

    Macheret, Sergey

    2005-05-16

    The paper reviews some of the recent studies of applications of weakly ionized plasmas to supersonic/hypersonic flight. Plasmas can be used simply as means of delivering energy (heating) to the flow, and also for electromagnetic flow control and magnetohydrodynamic (MHD) power generation. Plasma and MHD control can be especially effective in transient off-design flight regimes. In cold air flow, nonequilibrium plasmas must be created, and the ionization power budget determines design, performance envelope, and the very practicality of plasma/MHD devices. The minimum power budget is provided by electron beams and repetitive high-voltage nanosecond pulses, and the paper describes theoretical and computational modeling of plasmas created by the beams and repetitive pulses. The models include coupled equations for non-local and unsteady electron energy distribution function (modeled in forward-back approximation), plasma kinetics, and electric field. Recent experimental studies at Princeton University have successfully demonstrated stable diffuse plasmas sustained by repetitive nanosecond pulses in supersonic air flow, and for the first time have demonstrated the existence of MHD effects in such plasmas. Cold-air hypersonic MHD devices are shown to permit optimization of scramjet inlets at Mach numbers higher than the design value, while operating in self-powered regime. Plasma energy addition upstream of the inlet throat can increase the thrust by capturing more air (Virtual Cowl), or it can reduce the flow Mach number and thus eliminate the need for an isolator duct. In the latter two cases, the power that needs to be supplied to the plasma would be generated by an MHD generator downstream of the combustor, thus forming the 'reverse energy bypass' scheme. MHD power generation on board reentry vehicles is also discussed.

  4. Reaction kinetics for the high temperature oxidation of Pu--1wt%Ga in water vapor

    SciTech Connect (OSTI)

    Stakebake, J L; Saba, M A

    1988-01-01

    Oxidation of plutonium metal is greatly accelerated by the presence of water vapor. The magnitude of the effect of water vapor on oxidation kinetics is determined by temperature, water concentration, and oxygen concentration. Most of the previous work has been directed toward evaluating the effect of moisture on the atmospheric oxidation of plutonium. Work on the isolation and characterization of the water reaction with plutonium has been very limited. The present work was undertaken to determine the kinetics of the plutonium--water reaction over a wide range of temperature and pressure. Reaction kinetics were measured using a vacuum microbalance system. The temperature range investigated was 100--500/degree/C. The effect of water vapor pressure on reaction kinetics was determined at 300/degree/C by varying the water pressure from 0.1 to 15 Torr. 2 figs.

  5. Recent Advances in Detailed Chemical Kinetic Models for Large Hydrocarbon and Biodiesel Transportation Fuels

    SciTech Connect (OSTI)

    Westbrook, C K; Pitz, W J; Curran, H J; Herbinet, O; Mehl, M

    2009-03-30

    n-Hexadecane and 2,2,4,4,6,8,8-heptamethylnonane represent the primary reference fuels for diesel that are used to determine cetane number, a measure of the ignition property of diesel fuel. With the development of chemical kinetics models for these two primary reference fuels for diesel, a new capability is now available to model diesel fuel ignition. Also, we have developed chemical kinetic models for a whole series of large n-alkanes and a large iso-alkane to represent these chemical classes in fuel surrogates for conventional and future fuels. Methyl decanoate and methyl stearate are large methyl esters that are closely related to biodiesel fuels, and kinetic models for these molecules have also been developed. These chemical kinetic models are used to predict the effect of the fuel molecule size and structure on ignition characteristics under conditions found in internal combustion engines.

  6. Pyrolysis kinetics of scrap tire rubbers. 1: Using DTG and TGA

    SciTech Connect (OSTI)

    Kim, S.; Park, J.K.; Chun, H.D.

    1995-07-01

    Tire pyrolysis kinetics was investigated to explore an economically viable design for the pyrolysis process. Derivative thermogravimetry (DTG) and thermogravimetric analysis (TGA) were found to provide valuable information on pyrolysis kinetics and mechanisms of a heterogeneous compound like scrap tire rubbers. Kinetic parameters of each compositional compound were obtained by analyzing DTG and TGA results with a series of mathematical methods proposed in this study. The pyrolysis kinetics of the scrap tire rubbers tested was well accounted for by the first-order irreversible independent reactions of three compositional compounds. The sidewall and tread rubber exhibited different thermal degradation patterns, suggesting a compositional difference between them. Isothermal pyrolysis results showed that the sidewall rubber would hardly be degraded at low temperature regions (<600 K), whereas it would be more rapidly degraded than the tread rubber at higher temperatures ({>=}746 K). Because of the shorter pyrolysis time, the higher isothermal pyrolysis temperature appeared to be more economically favorable.

  7. Effects of Point Defects and Impurities on Kinetics in NaAlH4

    Broader source: Energy.gov [DOE]

    A presentation showing that point defects play an important role in the kinetics of NaAlH4 including vacancies and interstitials consistent with observed effects of Ti.

  8. Nonlinear and linear timescales near kinetic scales in solar wind turbulence

    SciTech Connect (OSTI)

    Matthaeus, W. H.; Wan, M.; Shay, M. A.; Oughton, S.; Osman, K. T.; Chapman, S. C.; Servidio, S.; Valentini, F.; Gary, S. P.; Roytershteyn, V.; Karimabadi, H.

    2014-08-01

    The application of linear kinetic treatments to plasma waves, damping, and instability requires favorable inequalities between the associated linear timescales and timescales for nonlinear (e.g., turbulence) evolution. In the solar wind these two types of timescales may be directly compared using standard Kolmogorov-style analysis and observational data. The estimated local (in scale) nonlinear magnetohydrodynamic cascade times, evaluated as relevant kinetic scales are approached, remain slower than the cyclotron period, but comparable to or faster than the typical timescales of instabilities, anisotropic waves, and wave damping. The variation with length scale of the turbulence timescales is supported by observations and simulations. On this basis the use of linear theory—which assumes constant parameters to calculate the associated kinetic rates—may be questioned. It is suggested that the product of proton gyrofrequency and nonlinear time at the ion gyroscales provides a simple measure of turbulence influence on proton kinetic behavior.

  9. Systems, methods and computer-readable media to model kinetic performance of rechargeable electrochemical devices

    DOE Patents [OSTI]

    Gering, Kevin L.

    2013-01-01

    A system includes an electrochemical cell, monitoring hardware, and a computing system. The monitoring hardware samples performance characteristics of the electrochemical cell. The computing system determines cell information from the performance characteristics. The computing system also analyzes the cell information of the electrochemical cell with a Butler-Volmer (BV) expression modified to determine exchange current density of the electrochemical cell by including kinetic performance information related to pulse-time dependence, electrode surface availability, or a combination thereof. A set of sigmoid-based expressions may be included with the modified-BV expression to determine kinetic performance as a function of pulse time. The determined exchange current density may be used with the modified-BV expression, with or without the sigmoid expressions, to analyze other characteristics of the electrochemical cell. Model parameters can be defined in terms of cell aging, making the overall kinetics model amenable to predictive estimates of cell kinetic performance along the aging timeline.

  10. PHASE-FIELD SIMULATION OF IRRADIATED METALS PART i: VOID KINETICS...

    Office of Scientific and Technical Information (OSTI)

    Title: PHASE-FIELD SIMULATION OF IRRADIATED METALS PART i: VOID KINETICS We present a phase-field model of void formation and evolution in irradiated metals by spatially and ...

  11. Kinetic model for an auroral double layer that spans many gravitational

    Office of Scientific and Technical Information (OSTI)

    scale heights (Journal Article) | SciTech Connect Kinetic model for an auroral double layer that spans many gravitational scale heights Citation Details In-Document Search Title: Kinetic model for an auroral double layer that spans many gravitational scale heights The electrostatic potential profile and the particle densities of a simplified auroral double layer are found using a relaxation method to solve Poisson's equation in one dimension. The electron and ion distribution functions for

  12. Kinetics of oxygen surface exchange on epitaxial Ruddlesden-Popper phases

    Office of Scientific and Technical Information (OSTI)

    and correlations to first-principles descriptors (Journal Article) | SciTech Connect Kinetics of oxygen surface exchange on epitaxial Ruddlesden-Popper phases and correlations to first-principles descriptors Citation Details In-Document Search This content will become publicly available on December 17, 2016 Title: Kinetics of oxygen surface exchange on epitaxial Ruddlesden-Popper phases and correlations to first-principles descriptors Through alignment of theoretical modeling with

  13. A new spin on neutrino quantum kinetics (Journal Article) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    A new spin on neutrino quantum kinetics Citation Details In-Document Search Title: A new spin on neutrino quantum kinetics Authors: Cirigliano, Vincenzo ; Fuller, George M. ; Vlasenko, Alexey Publication Date: 2015-07-01 OSTI Identifier: 1198653 Grant/Contract Number: 12-LR-237070 Type: Published Article Journal Name: Physics Letters. Section B Additional Journal Information: Journal Volume: 747; Journal Issue: C; Related Information: CHORUS Timestamp: 2016-05-17 15:17:45; Journal ID: ISSN

  14. A thermodynamic and kinetic model for paste-aggregate interactions and

    Office of Scientific and Technical Information (OSTI)

    the alkali-silica reaction (Journal Article) | SciTech Connect Title: A thermodynamic and kinetic model for paste-aggregate interactions and the alkali-silica reaction A new conceptual model is developed for ASR formation based on geochemical principles tied to aqueous speciation, silica solubility, kinetically controlled mineral dissolution, and diffusion. ASR development is driven largely by pH and silica gradients that establish geochemical microenvironments between paste and aggregate,

  15. PHASE-FIELD SIMULATION OF IRRADIATED METALS PART i: VOID KINETICS (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect METALS PART i: VOID KINETICS Citation Details In-Document Search Title: PHASE-FIELD SIMULATION OF IRRADIATED METALS PART i: VOID KINETICS We present a phase-field model of void formation and evolution in irradiated metals by spatially and temporally evolving vacancy and self-interstitial concentration fields. By incorporating a coupled set of Cahn-Hilliard and Allen-Cahn equations, the model captures the processes of point defect generation and recombination,

  16. PHASE-FIELD SIMULATION OF IRRADIATED METALS: PART II: GAS BUBBLE KINETICS

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect METALS: PART II: GAS BUBBLE KINETICS Citation Details In-Document Search Title: PHASE-FIELD SIMULATION OF IRRADIATED METALS: PART II: GAS BUBBLE KINETICS We present a phase-field model for inert gas bubble formation and evolution in irradiated metals. The model evolves vacancy, self-interstitial, and fission gas atoms through a coupled set of Cahn-Hilliard and Allen-Cahn equations, capturing the processes of defect generation, recombination, annihilation

  17. Renormalized linear kinetic theory as derived from quantum field theory: A

    Office of Scientific and Technical Information (OSTI)

    novel diagrammatic method for computing transport coefficients (Journal Article) | SciTech Connect Renormalized linear kinetic theory as derived from quantum field theory: A novel diagrammatic method for computing transport coefficients Citation Details In-Document Search Title: Renormalized linear kinetic theory as derived from quantum field theory: A novel diagrammatic method for computing transport coefficients We propose a novel diagrammatic method for computing transport coefficients in

  18. Systematic Method for the Kinetic Modeling of Temporally Resolved Hyperspectral Microscope Images of Fluorescently Labeled Cells

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    accelerated paper Systematic Method for the Kinetic Modeling of Temporally Resolved Hyperspectral Microscope Images of Fluorescently Labeled Cells PATRICK J. CUTLER, DAVID M. HAALAND, and PAUL J. GEMPERLINE* Department of Chemistry, East Carolina University, Greenville, North Carolina 27858 (P.J.C., P.J.G.); and Sandia National Laboratories, Albuquerque, New Mexico 87185-0895 (D.M.H.) In this paper we report the application of a novel method for fitting kinetic models to temporally resolved

  19. The kinetics of the [omega] to [alpha] phase transformation in Zr, Ti:

    Office of Scientific and Technical Information (OSTI)

    Analysis of data from shock-recovered samples and atomistic simulations (Journal Article) | SciTech Connect The kinetics of the [omega] to [alpha] phase transformation in Zr, Ti: Analysis of data from shock-recovered samples and atomistic simulations Citation Details In-Document Search Title: The kinetics of the [omega] to [alpha] phase transformation in Zr, Ti: Analysis of data from shock-recovered samples and atomistic simulations Authors: Zong, Hongxiang ; Lookman, Turab ; Ding, Xiangdong

  20. Three-Dimensional Modeling and Simulation of DNA Hybridization Kinetics and

    Office of Scientific and Technical Information (OSTI)

    Mass Transport as Functions of Temperature in a Microfluidic Channel. (Journal Article) | SciTech Connect Three-Dimensional Modeling and Simulation of DNA Hybridization Kinetics and Mass Transport as Functions of Temperature in a Microfluidic Channel. Citation Details In-Document Search Title: Three-Dimensional Modeling and Simulation of DNA Hybridization Kinetics and Mass Transport as Functions of Temperature in a Microfluidic Channel. Abstract not provided. Authors: Manginell, Ronald P ;

  1. Ultrafast kinetics subsequent to shock compression in an oxygen-balanced

    Office of Scientific and Technical Information (OSTI)

    mixture of nitromethane and hydrogen peroxide (Journal Article) | SciTech Connect Journal Article: Ultrafast kinetics subsequent to shock compression in an oxygen-balanced mixture of nitromethane and hydrogen peroxide Citation Details In-Document Search Title: Ultrafast kinetics subsequent to shock compression in an oxygen-balanced mixture of nitromethane and hydrogen peroxide Authors: Armstrong, M R ; Zaug, J M ; Grant, C D ; Crowhurst, J C ; Bastea, S Publication Date: 2014-03-03 OSTI

  2. Uncertainty analysis of multi-rate kinetics of uranium desorption from

    Office of Scientific and Technical Information (OSTI)

    sediments (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Uncertainty analysis of multi-rate kinetics of uranium desorption from sediments Citation Details In-Document Search Title: Uncertainty analysis of multi-rate kinetics of uranium desorption from sediments A multi-rate expression for uranyl [U(VI)] surface complexation reactions has been proposed to describe diffusion-limited U(VI) sorption/desorption in heterogeneous subsurface sediments. An

  3. KINETIC MONTE CARLO SIMULATIONS OF THE EFFECTS OF 1-D DEFECT TRANSPORT ON DEFECT REACTION KINETICS AND VOID LATTICE FORMATION DURING IRRADIATION

    SciTech Connect (OSTI)

    Heinisch, Howard L.; Singh, Bachu N.

    2003-03-01

    Within the last decade molecular dynamics simulations of displacement cascades have revealed that glissile clusters of self-interstitial crowdions are formed directly in cascades. Also, under various conditions, a crowdion cluster can change its Burgers vector and glide along a different close-packed direction. In order to incorporate the migration properties of crowdion clusters into analytical rate theory models, it is necessary to describe the reaction kinetics of defects that migrate one-dimensionally with occasional changes in their Burgers vector. To meet this requirement, atomic-scale kinetic Monte Carlo (KMC) simulations have been used to study the defect reaction kinetics of one-dimensionally migrating crowdion clusters as a function of the frequency of direction changes, specifically to determine the sink strengths for such one-dimensionally migrating defects. The KMC experiments are used to guide the development of analytical expressions for use in reaction rate theories and especially to test their validity. Excellent agreement is found between the results of KMC experiments and the analytical expressions derived for the transition from one-dimensional to three-dimensional reaction kinetics. Furthermore, KMC simulations have been performed to investigate the significant role of crowdion clusters in the formation and stability of void lattices. The necessity for both one-dimensional migration and Burgers vectors changes for achieving a stable void lattice is demonstrated.

  4. A Novel Approach to Experimental Studies of Mineral Dissolution Kinetics

    SciTech Connect (OSTI)

    Chen Zhu

    2006-08-31

    Currently, DOE is conducting pilot CO{sub 2} injection tests to evaluate the concept of geological sequestration. One strategy that potentially enhances CO{sub 2} solubility and reduces the risk of CO{sub 2} leak back to the surface is dissolution of indigenous minerals in the geological formation and precipitation of secondary carbonate phases, which increases the brine pH and immobilizes CO{sub 2}. Clearly, the rates at which these dissolution and precipitation reactions occur directly determine the efficiency of this strategy. However, one of the fundamental problems in modern geochemistry is the persistent two to five orders of magnitude discrepancy between laboratory measured and field derived feldspar dissolution rates. To date, there is no real guidance as to how to predict silicate reaction rates for use in quantitative models. Current models for assessment of geological carbon sequestration have generally opted to use laboratory rates, in spite of the dearth of such data for compositionally complex systems, and the persistent disconnect between laboratory and field applications. Therefore, a firm scientific basis for predicting silicate reaction kinetics in CO2 injected geological formations is urgently needed to assure the reliability of the geochemical models used for the assessments of carbon sequestration strategies. The funded experimental and theoretical study attempts to resolve this outstanding scientific issue by novel experimental design and theoretical interpretation to measure silicate dissolution rates and iron carbonate precipitation rates at conditions pertinent to geological carbon sequestration. In the second year of the project, we completed CO{sub 2}-Navajo sandstone interaction batch and flow-through experiments and a Navajo sandstone dissolution experiment without the presence of CO{sub 2} at 200 C and 250-300 bars, and initiated dawsonite dissolution and solubility experiments. We also performed additional 5-day experiments at the same conditions as alkali-feldspar dissolution experiments with and without the presence of CO{sub 2} performed in the first year to check the validation of the experiments and analysis. The changes of solution chemistry as dissolution experiments progressed were monitored with on-line sampling of the aqueous phase at the constant temperature and pressure. These data allow calculating overall apparent mineral (feldspars and sandstones) dissolution rates and secondary mineral precipitation rates as a function of saturation states. State-of-the-art atomic resolution transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electron microprobe was used to characterize the products and reactants. Reaction-path geochemical modeling was used to interpret the experimental results of alkali-feldspar dissolution experiments without the presence of CO{sub 2}. Two manuscripts are near completion. Also during the second year, our education goal of graduate student training has been advanced. A Ph. D. student at Indiana University is progressing well in the degree program and has taken geochemical modeling, SEM, and TEM courses, which will facilitate research in the third year. A Ph. D. student at University of Minnesota had graduated. With the success of training of graduate students and excellent experimental data in the second year, we anticipate a more fruitful year in the third year.

  5. Isotope exchange kinetics in metal hydrides I : TPLUG model.

    SciTech Connect (OSTI)

    Larson, Rich; James, Scott Carlton; Nilson, Robert H.

    2011-05-01

    A one-dimensional isobaric reactor model is used to simulate hydrogen isotope exchange processes taking place during flow through a powdered palladium bed. This simple model is designed to serve primarily as a platform for the initial development of detailed chemical mechanisms that can then be refined with the aid of more complex reactor descriptions. The one-dimensional model is based on the Sandia in-house code TPLUG, which solves a transient set of governing equations including an overall mass balance for the gas phase, material balances for all of the gas-phase and surface species, and an ideal gas equation of state. An energy equation can also be solved if thermodynamic properties for all of the species involved are known. The code is coupled with the Chemkin package to facilitate the incorporation of arbitrary multistep reaction mechanisms into the simulations. This capability is used here to test and optimize a basic mechanism describing the surface chemistry at or near the interface between the gas phase and a palladium particle. The mechanism includes reversible dissociative adsorptions of the three gas-phase species on the particle surface as well as atomic migrations between the surface and the bulk. The migration steps are more general than those used previously in that they do not require simultaneous movement of two atoms in opposite directions; this makes possible the creation and destruction of bulk vacancies and thus allows the model to account for variations in the bulk stoichiometry with isotopic composition. The optimization code APPSPACK is used to adjust the mass-action rate constants so as to achieve the best possible fit to a given set of experimental data, subject to a set of rigorous thermodynamic constraints. When data for nearly isothermal and isobaric deuterium-to-hydrogen (D {yields} H) and hydrogen-to-deuterium (H {yields} D) exchanges are fitted simultaneously, results for the former are excellent, while those for the latter show pronounced deviations at long times. These discrepancies can be overcome by postulating the presence of a surface poison such as carbon monoxide, but this explanation is highly speculative. When the method is applied to D {yields} H exchanges intentionally poisoned by known amounts of CO, the fitting results are noticeably degraded from those for the nominally CO-free system but are still tolerable. When TPLUG is used to simulate a blowdown-type experiment, which is characterized by large and rapid changes in both pressure and temperature, discrepancies are even more apparent. Thus, it can be concluded that the best use of TPLUG is not in simulating realistic exchange scenarios, but in extracting preliminary estimates for the kinetic parameters from experiments in which variations in temperature and pressure are intentionally minimized.

  6. Studies of Reaction Kinetics of Methane Hydrate Dissocation in Porous Media

    SciTech Connect (OSTI)

    Moridis, George J.; Seol, Yongkoo; Kneafsey, Timothy J.

    2005-03-10

    The objective of this study is the description of the kinetic dissociation of CH4-hydrates in porous media, and the determination of the corresponding kinetic parameters. Knowledge of the kinetic dissociation behavior of hydrates can play a critical role in the evaluation of gas production potential of gas hydrate accumulations in geologic media. We analyzed data from a sequence of tests of CH4-hydrate dissociation by means of thermal stimulation. These tests had been conducted on sand cores partially saturated with water, hydrate and CH4 gas, and contained in an x-ray-transparent aluminum pressure vessel. The pressure, volume of released gas, and temperature (at several locations within the cores) were measured. To avoid misinterpreting local changes as global processes, x-ray computed tomography scans provided accurate images of the location and movement of the reaction interface during the course of the experiments. Analysis of the data by means of inverse modeling (history matching ) provided estimates of the thermal properties and of the kinetic parameters of the hydration reaction in porous media. Comparison of the results from the hydrate-bearing porous media cores to those from pure CH4-hydrate samples provided a measure of the effect of the porous medium on the kinetic reaction. A tentative model of composite thermal conductivity of hydrate-bearing media was also developed.

  7. Exploring growth kinetics of carbon nanotube arrays by in situ optical diagnostics and modeling

    SciTech Connect (OSTI)

    Puretzky, Alexander A; Geohegan, David B; Pannala, Sreekanth; Rouleau, Christopher

    2014-01-01

    Simple kinetic models of carbon nanotube growth have been able to successfully link together many experimental parameters involved in the growth of carbon nanotubes for practical applications including the prediction of growth rates, terminal lengths, number of walls, activation energies, and their dependences on the growth environment. The implications of recent experiments utilizing in situ monitoring of carbon nanotube growth on our past kinetic model are first reviewed. Then, sub-second pulsed feedstock gas introduction is discussed to explore the nucleation and initial growth of carbon nanotubes in the context of the kinetic model. Moreover, kinetic effects in "pulsed CVD" - using repeated pulsed gas introduction to stop and restart nanotube growth - are explored to understand renucleation, the origin of alignment in nanotube arrays, and incremental growth. Time-resolved reflectivity of the surface is used to remotely understand the kinetics of nucleation and the coordinated growth of arrays. This approach demonstrates that continuous vertically aligned single wall carbon nanotubes can be grown incrementally by pulsed CVD, and that the first exposure of fresh catalyst to feedstock gas is critical to nanotubes site density required for coordinated growth. Aligned nanotube arrays (as short as 60 nm) are shown to nucleate and grow within single, sub-second gas pulses. The multiple-pulse growth experiments (> 100 pulses) show that a high fraction of nanotubes renucleate on subsequent gas pulses.

  8. Excitation of kinetic geodesic acoustic modes by drift waves in nonuniform plasmas

    SciTech Connect (OSTI)

    Qiu, Z.; Chen, L.; Dept. Physics and Astronomy, Univ. of California, Irvine, California 92697-4575 ; Zonca, F.; Associazione Euratom-ENEA sulla Fusione, C.P. 65 - I-00044 - Frascati

    2014-02-15

    Effects of system nonuniformities and kinetic dispersiveness on the spontaneous excitation of Geodesic Acoustic Mode (GAM) by Drift Wave (DW) turbulence are investigated based on nonlinear gyrokinetic theory. The coupled nonlinear equations describing parametric decay of DW into GAM and DW lower sideband are derived and then solved both analytically and numerically to investigate the effects on the parametric decay process due to system nonuniformities, such as nonuniform diamagnetic frequency, finite radial envelope of DW pump, and kinetic dispersiveness. It is found that the parametric decay process is a convective instability for typical tokamak parameters when finite group velocities of DW and GAM associated with kinetic dispersiveness and finite radial envelope are taken into account. When, however, nonuniformity of diamagnetic frequency is taken into account, the parametric decay process becomes, time asymptotically, a quasi-exponentially growing absolute instability.

  9. Fokker–Planck kinetic modeling of suprathermal α-particles in a fusion plasma

    SciTech Connect (OSTI)

    Peigney, B.E.

    2014-12-01

    We present an ion kinetic model describing the transport of suprathermal α-particles in inertial fusion targets. The analysis of the underlying physical model enables us to develop efficient numerical methods to simulate the creation, transport and collisional relaxation of fusion reaction products (α-particles) at a kinetic level. The model assumes spherical symmetry in configuration space and axial symmetry in velocity space around the mean flow velocity. A two-energy-scale approach leads to a self-consistent modeling of the coupling between suprathermal α-particles and the thermal bulk of the imploding plasma. This method provides an accurate numerical treatment of energy deposition and transport processes involving suprathermal particles. The numerical tools presented here are then validated against known analytical results. This enables us to investigate the potential role of ion kinetic effects on the physics of ignition and thermonuclear burn in inertial confinement fusion schemes.

  10. Kinetic and thermodynamic study of the liquid-phase etherification of isoamylenes with methanol

    SciTech Connect (OSTI)

    Piccoli, R.L. ); Lovisi, H.R. )

    1995-02-01

    The kinetics and thermodynamics of liquid-phase etherification of isoamylenes with methanol on ion exchange catalyst (Amberlyst 15) were studied. Thermodynamic properties and rate data were obtained in a batch reactor operating under 1,013 kPa and 323--353 K. The kinetic equation was modeled following the Langmuir-Hinshelwood-Hougen-Watson formalism according to a proposed surface mechanism where the rate-controlling step is the surface reaction. According to the experimental results, methanol adsorbs very strongly on the active sites, covering them completely, and thus the reaction follows an apparent first-order behavior. The isoamylenes, according to the proposed mechanism, adsorb simultaneously on the same single active center already occupied by methanol, migrating through the liquid layer formed by the alcohol around the catalyst to react in the acidic site. From the proposed mechanism a model was suggested and the kinetic and thermodynamic parameters were obtained using nonlinear estimation methods.

  11. Crossing the mesoscale no-mans land via parallel kinetic Monte Carlo.

    SciTech Connect (OSTI)

    Garcia Cardona, Cristina (San Diego State University); Webb, Edmund Blackburn, III; Wagner, Gregory John; Tikare, Veena; Holm, Elizabeth Ann; Plimpton, Steven James; Thompson, Aidan Patrick; Slepoy, Alexander (U. S. Department of Energy, NNSA); Zhou, Xiao Wang; Battaile, Corbett Chandler; Chandross, Michael Evan

    2009-10-01

    The kinetic Monte Carlo method and its variants are powerful tools for modeling materials at the mesoscale, meaning at length and time scales in between the atomic and continuum. We have completed a 3 year LDRD project with the goal of developing a parallel kinetic Monte Carlo capability and applying it to materials modeling problems of interest to Sandia. In this report we give an overview of the methods and algorithms developed, and describe our new open-source code called SPPARKS, for Stochastic Parallel PARticle Kinetic Simulator. We also highlight the development of several Monte Carlo models in SPPARKS for specific materials modeling applications, including grain growth, bubble formation, diffusion in nanoporous materials, defect formation in erbium hydrides, and surface growth and evolution.

  12. High-order continuum kinetic method for modeling plasma dynamics in phase space

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Vogman, G. V.; Colella, P.; Shumlak, U.

    2014-12-15

    Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods. Advances in continuum method capabilities for modeling kinetic phenomena in plasmas require the development of validation tools in higher dimensional phase space and an ability to handle non-cartesian geometries. To that end, a new benchmark for validating Vlasov-Poisson simulations in 3D (x,vx,vy) is presented. The benchmark is based on the Dory-Guest-Harris instability and is successfully used to validate a continuum finite volumemore » algorithm. To address challenges associated with non-cartesian geometries, unique features of cylindrical phase space coordinates are described. Preliminary results of continuum kinetic simulations in 4D (r,z,vr,vz) phase space are presented.« less

  13. Catalyst and its diameter dependent growth kinetics of CVD grown GaN nanowires

    SciTech Connect (OSTI)

    Samanta, Chandan [Department of Physics, Indian Institute of Technology Kanpur (India)] [Department of Physics, Indian Institute of Technology Kanpur (India); Chander, D. Sathish [Department of Physics, Indian Institute of Technology Kanpur (India) [Department of Physics, Indian Institute of Technology Kanpur (India); Department of Mechanical Engineering, Indian Institute of Technology Kanpur (India); Ramkumar, J. [Department of Mechanical Engineering, Indian Institute of Technology Kanpur (India)] [Department of Mechanical Engineering, Indian Institute of Technology Kanpur (India); Dhamodaran, S., E-mail: kdams2003@gmail.com [Department of Physics, Indian Institute of Technology Kanpur (India)

    2012-04-15

    Graphical abstract: GaN nanowires with controlled diameter and aspect ratio has been grown using a simple CVD technique. The growth kinetics of CVD grown nanowires investigated in detail for different catalysts and their diameters. A critical diameter important to distinguish the growth regimes has been discussed in detail. The results are important which demonstrates the growth of diameter and aspect ratio controlled GaN nanowires and also understand their growth kinetics. Highlights: Black-Right-Pointing-Pointer Controlled diameter and aspect ratio of GaN nanowires achieved in simple CVD reactor. Black-Right-Pointing-Pointer Nanowire growth kinetics for different catalyst and its diameters were understood. Black-Right-Pointing-Pointer Adatoms vapor pressure inside reactor plays a crucial role in growth kinetics. Black-Right-Pointing-Pointer Diffusion along nanowire sidewalls dominate for gold and nickel catalysts. Black-Right-Pointing-Pointer Gibbs-Thomson effect dominates for palladium catalyst. -- Abstract: GaN nanowires were grown using chemical vapor deposition with controlled aspect ratio. The catalyst and catalyst-diameter dependent growth kinetics is investigated in detail. We first discuss gold catalyst diameter dependent growth kinetics and subsequently compare with nickel and palladium catalyst. For different diameters of gold catalyst there was hardly any variation in the length of the nanowires but for other catalysts with different diameter a strong length variation of the nanowires was observed. We calculated the critical diameter dependence on adatoms pressure inside the reactor and inside the catalytic particle. This gives an increasing trend in critical diameter as per the order gold, nickel and palladium for the current set of experimental conditions. Based on the critical diameter, with gold and nickel catalyst the nanowire growth was understood to be governed by limited surface diffusion of adatoms and by Gibbs-Thomson effect for the palladium catalyst.

  14. A KINETIC S'FUDY OF METHANOL SYNTHESIS IN A SLURRY REACTOR USING

    Office of Scientific and Technical Information (OSTI)

    KINETIC S'FUDY OF METHANOL SYNTHESIS IN A SLURRY REACTOR USING a CuO/ZnO/AI20 3 CATALYST _E/PC/89787--_ DE92 016818 A thesis by HAMAD ABDULWAHAB AL-ADW/_rI A KINETIC STUDY OF METHANOL SYNTHESIS IN A. SLURRY REACTOR USING a CuO/ZnO/AI20 3 CATALYST A thesis by HAMAD ABDULWAHAB AL-ADWAN1 Approved as to style and content by: NJ . . _ _LI ,,l, ,m , Michael Rosynek JR., G, Anthony li P" ¥ (Co-Chair of Committee) (Member) Ayd,,, Akgol -) tri n ILayTnond W. Flumerfelt (Co-Chair of Committee) (Head

  15. Fully Kinetic Simulations of MegaJoule-Scale Dense Plasma Focus (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Journal Article: Fully Kinetic Simulations of MegaJoule-Scale Dense Plasma Focus Citation Details In-Document Search Title: Fully Kinetic Simulations of MegaJoule-Scale Dense Plasma Focus Authors: Schmidt, A ; Link, A ; Welch, D ; Meehan, T ; Tang, V ; Halvorson, C ; May, M ; Hagen, E C Publication Date: 2014-09-19 OSTI Identifier: 1169854 Report Number(s): LLNL-JRNL-661056 DOE Contract Number: DE-AC52-07NA27344 Resource Type: Journal Article Resource Relation:

  16. Mechanism and Kinetic Modeling of Hydrogenation in The Organic Getter/Pd

    Office of Scientific and Technical Information (OSTI)

    Catalyst/Activated Carbon Systems (Journal Article) | SciTech Connect Mechanism and Kinetic Modeling of Hydrogenation in The Organic Getter/Pd Catalyst/Activated Carbon Systems Citation Details In-Document Search Title: Mechanism and Kinetic Modeling of Hydrogenation in The Organic Getter/Pd Catalyst/Activated Carbon Systems Authors: Dinh, L N ; Cairns, G A ; Strickland, R ; McLean II, W ; Maxwell, R S Publication Date: 2014-09-25 OSTI Identifier: 1182700 Report Number(s): LLNL-JRNL-662218

  17. Electron kinetic effects on interferometry and polarimetry in high temperature fusion plasmas

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    196 This content was downloaded on 12/12/2013 at 20:27 Please note that terms and conditions apply. Electron kinetic effects on interferometry and polarimetry in high temperature fusion plasmas View the table of contents for this issue, or go to the journal homepage for more Home Search Collections Journals About Contact us My IOPscience IOP PUBLISHING and INTERNATIONAL ATOMIC ENERGY AGENCY NUCLEAR FUSION Nucl. Fusion 53 (2013) 113005 (9pp) doi:10.1088/0029-5515/53/11/113005 Electron kinetic

  18. Relativistic theory of nuclear spin-rotation tensor with kinetically balanced rotational London orbitals

    SciTech Connect (OSTI)

    Xiao, Yunlong; Zhang, Yong; Liu, Wenjian

    2014-10-28

    Both kinetically balanced (KB) and kinetically unbalanced (KU) rotational London orbitals (RLO) are proposed to resolve the slow basis set convergence in relativistic calculations of nuclear spin-rotation (NSR) coupling tensors of molecules containing heavy elements [Y. Xiao and W. Liu, J. Chem. Phys. 138, 134104 (2013)]. While they perform rather similarly, the KB-RLO Ansatz is clearly preferred as it ensures the correct nonrelativistic limit even with a finite basis. Moreover, it gives rise to the same direct relativistic mapping between nuclear magnetic resonance shielding and NSR coupling tensors as that without using the London orbitals [Y. Xiao, Y. Zhang, and W. Liu, J. Chem. Theory Comput. 10, 600 (2014)].

  19. Structure and charging kinetics of electrical double layers at large electrode voltage

    SciTech Connect (OSTI)

    Cagle, Clint [Clemson University; Feng, Guang [Clemson University; Qiao, Rui [Clemson University; Huang, Jingsong [ORNL; Sumpter, Bobby G [ORNL; Meunier, Vincent [ORNL

    2009-01-01

    The structure and charging kinetics of electrical double layers (EDLs) at interfaces of NaCl solutions and planar electrodes are studied by molecular dynamics (MD) and Poisson Nernst Planck (PNP) simulations. Based on the MD results and prior experimental data, we show that counterion packing in planar EDLs does not reach the steric limit at electrode voltages below 1 V. In addition, we demonstrate that a PNP model, when complemented with a Stern model, can be effectively used to capture the overall charging kinetics. However, the PNP/Stern model can only give a qualitative description of the fine features of the EDL.

  20. Approximate models for the ion-kinetic regime in inertial-confinement-fusion capsule implosions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hoffman, Nelson M.; Zimmerman, George B.; Molvig, Kim; Rinderknecht, Hans G.; Rosenberg, Michael J.; Albright, B. J.; Simakov, Andrei N.; Sio, Hong; Zylstra, Alex B.; Johnson, Maria Gatu; et al

    2015-05-19

    “Reduced” (i.e., simplified or approximate) ion-kinetic (RIK) models in radiation-hydrodynamic simulations permit a useful description of inertial-confinement-fusion (ICF) implosions where kinetic deviations from hydrodynamic behavior are important. For implosions in or near the kinetic regime (i.e., when ion mean free paths are comparable to the capsule size), simulations using a RIK model give a detailed picture of the time- and space-dependent structure of imploding capsules, allow an assessment of the relative importance of various kinetic processes during the implosion, enable explanations of past and current observations, and permit predictions of the results of future experiments. The RIK simulation method describedmore » here uses moment-based reduced kinetic models for transport of mass, momentum, and energy by long-mean-free-path ions, a model for the decrease of fusion reactivity owing to the associated modification of the ion distribution function, and a model of hydrodynamic turbulent mixing. The transport models are based on local gradient-diffusion approximations for the transport of moments of the ion distribution functions, with coefficients to impose flux limiting or account for transport modification. After calibration against a reference set of ICF implosions spanning the hydrodynamic-to-kinetic transition, the method has useful, quantifiable predictive ability over a broad range of capsule parameter space. Calibrated RIK simulations show that an important contributor to ion species separation in ICF capsule implosions is the preferential flux of longer-mean-free-path species out of the fuel and into the shell, leaving the fuel relatively enriched in species with shorter mean free paths. Also, the transport of ion thermal energy is enhanced in the kinetic regime, causing the fuel region to have a more uniform, lower ion temperature, extending over a larger volume, than implied by clean simulations. We expect that the success of our simple approach will motivate continued theoretical research into the development of first-principles-based, comprehensive, self-consistent, yet useable models of kinetic multispecies ion behavior in ICF plasmas.« less

  1. Phase-field Model for Stress-dependent Ginsburg-Landau Kinetics for Large

    Office of Scientific and Technical Information (OSTI)

    Deformation of Silicon Anodes (Technical Report) | SciTech Connect Technical Report: Phase-field Model for Stress-dependent Ginsburg-Landau Kinetics for Large Deformation of Silicon Anodes Citation Details In-Document Search Title: Phase-field Model for Stress-dependent Ginsburg-Landau Kinetics for Large Deformation of Silicon Anodes Authors: An, Y ; Wood, B C ; Tang, M ; Jiang, H Publication Date: 2014-10-14 OSTI Identifier: 1172293 Report Number(s): LLNL-SR-662739 DOE Contract Number:

  2. Twenty Five Years of Vibrational Kinetics and Negative Ion Production in H2 Plasmas: Modelling Aspects

    SciTech Connect (OSTI)

    Capitelli, M.; De Pascale, O.; Diomede, P.; Gorse, C.; Longo, S.; Pagano, D.; Gicquel, A.; Hassouni, K.

    2005-04-06

    Different approaches to study vibrational kinetics coupled to electron one for modeling different kinds of negative ion sources are presented. In particular two types of sources are investigated. The first one is a classical negative ion source in which the plasma is generated by thermoemitted electrons; in the second one, electrons already present in the mixture are accelerated by an RF field to sufficiently high energy to ionize the gas molecules. For the first kind of ion source a new computational scheme is presented to couple heavy particle and electron kinetics. Moreover models developed for an RF inductive discharge and for a parallel plate discharge are described.

  3. Approximate models for the ion-kinetic regime in inertial-confinement-fusion capsule implosions

    SciTech Connect (OSTI)

    Hoffman, Nelson M.; Zimmerman, George B.; Molvig, Kim; Rinderknecht, Hans G.; Rosenberg, Michael J.; Albright, B. J.; Simakov, Andrei N.; Sio, Hong; Zylstra, Alex B.; Johnson, Maria Gatu; Séguin, Fredrick H.; Frenje, Johan A.; Li, C. K.; Petrasso, Richard D.; Higdon, David M.; Srinivasan, Gowri; Glebov, Vladimir Yu.; Stoeckl, Christian; Seka, Wolf; Sangster, T. Craig

    2015-05-19

    “Reduced” (i.e., simplified or approximate) ion-kinetic (RIK) models in radiation-hydrodynamic simulations permit a useful description of inertial-confinement-fusion (ICF) implosions where kinetic deviations from hydrodynamic behavior are important. For implosions in or near the kinetic regime (i.e., when ion mean free paths are comparable to the capsule size), simulations using a RIK model give a detailed picture of the time- and space-dependent structure of imploding capsules, allow an assessment of the relative importance of various kinetic processes during the implosion, enable explanations of past and current observations, and permit predictions of the results of future experiments. The RIK simulation method described here uses moment-based reduced kinetic models for transport of mass, momentum, and energy by long-mean-free-path ions, a model for the decrease of fusion reactivity owing to the associated modification of the ion distribution function, and a model of hydrodynamic turbulent mixing. The transport models are based on local gradient-diffusion approximations for the transport of moments of the ion distribution functions, with coefficients to impose flux limiting or account for transport modification. After calibration against a reference set of ICF implosions spanning the hydrodynamic-to-kinetic transition, the method has useful, quantifiable predictive ability over a broad range of capsule parameter space. Calibrated RIK simulations show that an important contributor to ion species separation in ICF capsule implosions is the preferential flux of longer-mean-free-path species out of the fuel and into the shell, leaving the fuel relatively enriched in species with shorter mean free paths. Also, the transport of ion thermal energy is enhanced in the kinetic regime, causing the fuel region to have a more uniform, lower ion temperature, extending over a larger volume, than implied by clean simulations. We expect that the success of our simple approach will motivate continued theoretical research into the development of first-principles-based, comprehensive, self-consistent, yet useable models of kinetic multispecies ion behavior in ICF plasmas.

  4. Computational model, method, and system for kinetically-tailoring multi-drug chemotherapy for individuals

    DOE Patents [OSTI]

    Gardner, Shea Nicole

    2007-10-23

    A method and system for tailoring treatment regimens to individual patients with diseased cells exhibiting evolution of resistance to such treatments. A mathematical model is provided which models rates of population change of proliferating and quiescent diseased cells using cell kinetics and evolution of resistance of the diseased cells, and pharmacokinetic and pharmacodynamic models. Cell kinetic parameters are obtained from an individual patient and applied to the mathematical model to solve for a plurality of treatment regimens, each having a quantitative efficacy value associated therewith. A treatment regimen may then be selected from the plurlaity of treatment options based on the efficacy value.

  5. Measuring Photochemical Kinetics in Submonolayer Films by Transient ATR Spectroscopy on a Multimode Planar Waveguide

    SciTech Connect (OSTI)

    Simon, Anne M.; Marucci, Nicole E.; Saavedra, S. Scott

    2011-07-15

    Understanding the kinetics of reactions in molecular thin films can aid in the molecular engineering of organic photovoltaics and biosensors. Using two analytical methods, transient absorbance spectroscopy (TAS) and attenuated total reflectance (ATR), in a relatively simple arrangement when compared with previous TAS/ATR instruments to interrogate molecular structure and photochemistry at interfaces. The multimode planar waveguide geometry provides a significant path length enhancement relative to a conventional transmission geometry, making it feasible to perform measurements on low-surface-coverage films. This work demonstrates that TAS/ATR can be used to probe structure and photochemical kinetics in molecular films at extremely low surface coverages.

  6. THE 8TH NON-LTE KINETICS WORKSHOP (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    THE 8TH NON-LTE KINETICS WORKSHOP Citation Details In-Document Search Title: THE 8TH NON-LTE KINETICS WORKSHOP Authors: Fontes, Christopher J. [1] ; Armstrong, Gregory [1] ; Colgan, James P. [1] ; Kilcrease, David P. [1] ; Zhang, Honglin [1] + Show Author Affiliations Los Alamos National Laboratory [Los Alamos National Laboratory Publication Date: 2013-11-07 OSTI Identifier: 1104901 Report Number(s): LA-UR-13-28555 DOE Contract Number: AC52-06NA25396 Resource Type: Conference Resource Relation:

  7. Thermodynamic and kinetic analyses of the CO2 chemisorption mechanism on

    Office of Scientific and Technical Information (OSTI)

    Na2TiO3: Experimental and theoretical evidences (Journal Article) | SciTech Connect Thermodynamic and kinetic analyses of the CO2 chemisorption mechanism on Na2TiO3: Experimental and theoretical evidences Citation Details In-Document Search Title: Thermodynamic and kinetic analyses of the CO2 chemisorption mechanism on Na2TiO3: Experimental and theoretical evidences ABSTRACT: Sodium metatitanate (Na2TiO3) was successfully synthesized via a solid-state reaction. The Na2TiO3 structure and

  8. Inflation driven by scalar field with non-minimal kinetic coupling with Higgs and quadratic potentials

    SciTech Connect (OSTI)

    Granda, L.N.

    2011-04-01

    We study a scalar field with non-minimal kinetic coupling to itself and to the curvature. The slow rolling conditions allowing an inflationary background have been found. The quadratic and Higgs type potentials have been considered, and the corresponding values for the scalar fields at the end of inflation allows to recover the connection with particle physics.

  9. Kinetics of Uranium(VI) Desorption from Contaminated Sediments: Effect of Geochemical Conditions and Model Evaluation

    SciTech Connect (OSTI)

    Liu, Chongxuan; Shi, Zhenqing; Zachara, John M.

    2009-09-01

    Stirred-flow cell experiments were performed to investigate the kinetics of uranyl [U(VI)] desorption from a contaminated sediment collected from the Hanford 300 Area at the US Department of Energy (DOE) Hanford Site, Washington. Three influent solutions of variable pH, Ca and carbonate concentrations that affected U(VI) aqueous and surface speciation were used under dynamic flow conditions to evaluate the effect of geochemical conditions on the rate of U(VI) desorption. The measured rate of U(VI) desorption varied with solution chemical composition that evolved as a result of thermodynamic and kinetic interactions between the influent solutions and sediment. The solution chemical composition that led to a lower equilibrium U(VI) sorption to the solid phase yielded a faster desorption rate. The experimental results were used to evaluate a multi-rate, surface complexation model (SCM) that has been proposed to describe U(VI) desorption kinetics in the Hanford sediment that contained complex sorbed U(VI) species in mass transfer limited domains. The model was modified and supplemented by including multi-rate, ion exchange reactions to describe the geochemical interactions between the solutions and sediment. With the same set of model parameters, the modified model reasonably well described the evolution of major ions and the rates of U(VI) desorption under variable geochemical and flow conditions, implying that the multi-rate SCM is an effective way to describe U(VI) desorption kinetics in subsurface sediments.

  10. Comparison of kinetic and equilibrium reaction models insimulating gas hydrate behavior in porous media

    SciTech Connect (OSTI)

    Kowalsky, Michael B.; Moridis, George J.

    2006-11-29

    In this study we compare the use of kinetic and equilibriumreaction models in the simulation of gas (methane) hydrate behavior inporous media. Our objective is to evaluate through numerical simulationthe importance of employing kinetic versus equilibrium reaction modelsfor predicting the response of hydrate-bearing systems to externalstimuli, such as changes in pressure and temperature. Specifically, we(1) analyze and compare the responses simulated using both reactionmodels for natural gas production from hydrates in various settings andfor the case of depressurization in a hydrate-bearing core duringextraction; and (2) examine the sensitivity to factors such as initialhydrate saturation, hydrate reaction surface area, and numericaldiscretization. We find that for large-scale systems undergoing thermalstimulation and depressurization, the calculated responses for bothreaction models are remarkably similar, though some differences areobserved at early times. However, for modeling short-term processes, suchas the rapid recovery of a hydrate-bearing core, kinetic limitations canbe important, and neglecting them may lead to significantunder-prediction of recoverable hydrate. The use of the equilibriumreaction model often appears to be justified and preferred for simulatingthe behavior of gas hydrates, given that the computational demands forthe kinetic reaction model far exceed those for the equilibrium reactionmodel.

  11. Kinetic effect of Pd additions on the hydrogen uptake of chemically activated, ultramicroporous carbon

    SciTech Connect (OSTI)

    Bhat, Vinay V; Contescu, Cristian I; Gallego, Nidia C

    2010-01-01

    The effect of mixing chemically-activated ultramicroporous carbon (UMC) with Pd nanopowder is investigated. Results show that Pd addition doubles the rate of hydrogen uptake, but does not enhance the hydrogen capacity or improve desorption kinetics. The effect of Pd on the rate of hydrogen adsorption supports the occurrence of the hydrogen spillover mechanism in the Pd - UMC system.

  12. Spin-selective recombination kinetics of a carotenoid-porphyrin-fullerene radical pair

    SciTech Connect (OSTI)

    Maeda, Kiminori; Wedge, Christopher J.; Storey, Jonathan G.; Henbest, Kevin B.; Liddell, Paul A.; Kodis, Gerdenis; Gust, Devens; Hore, P. J.; Timmel, Christiane R.

    2011-01-01

    We determine the spin-selective kinetics of a carotenoidporphyrinfullerene triad that has previously been used to establish the principle that a photochemical reaction could form the basis of the magnetic compass sensor of migratory birds and show that its magnetic sensitivity can be understood without invoking quantum Zeno effects.

  13. Hybrid simulations of magnetic reconnection with kinetic ions and fluid electron pressure anisotropy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Le, A.; Daughton, W.; Karimabadi, H.; Egedal, J.

    2016-03-16

    We present the first hybrid simulations with kinetic ions and recently developed equations of state for the electron fluid appropriate for reconnection with a guide field. The equations of state account for the main anisotropy of the electron pressure tensor.Magnetic reconnection is studied in two systems, an initially force-free current sheet and a Harris sheet. The hybrid model with the equations of state is compared to two other models, hybrid simulations with isothermal electrons and fully kinetic simulations. Including the anisotropicequations of state in the hybrid model provides a better match to the fully kinetic model. In agreement with fullymore » kinetic results, the main feature captured is the formation of an electron current sheet that extends several ion inertial lengths. This electron current sheet modifies the Hall magnetic field structure near the X-line, and it is not observed in the standard hybrid model with isotropic electrons. The saturated reconnection rate in this regime nevertheless remains similar in all three models. Here, implications for global modeling are discussed.« less

  14. Growth kinetics of AlFe intermetallic compounds during annealing treatment of friction stir lap welds

    SciTech Connect (OSTI)

    Movahedi, M., E-mail: m_movahedi@sharif.edu [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Ave., Tehran (Iran, Islamic Republic of); Kokabi, A.H., E-mail: kokabi@sharif.edu [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Ave., Tehran (Iran, Islamic Republic of); Seyed Reihani, S.M., E-mail: reihani@sharif.edu [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Ave., Tehran (Iran, Islamic Republic of); Najafi, H., E-mail: hossein.najafi@epfl.ch [Institute of Condensed Matter Physics (ICMP), EPFL, CH-1015 Lausanne (Switzerland); Farzadfar, S.A., E-mail: seyed-amir.farzadfar@mail.mcgill.ca [McGill University, Department of Materials Engineering, Montreal, QC H3A 2B2 (Canada); Cheng, W.J., E-mail: d9603505@mail.ntust.edu.tw [Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, ROC (China); Wang, C.J., E-mail: cjwang@mail.ntust.edu.tw [Department of Mechanical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, ROC (China)

    2014-04-01

    In this study, we explored the growth kinetics of the AlFe intermetallic (IM) layer at the joint interface of the St-12/Al-5083 friction stir lap welds during post-weld annealing treatment at 350, 400 and 450 C for 30 to 180 min. Optical microscope (OM), field emission gun scanning electron microscope (FEG-SEM) and transmission electron microscope (TEM) were employed to investigate the structure of the weld zone. The thickness and composition of the IM layers were evaluated using image analysis system and electron back-scatter diffraction (EBSD), respectively. Moreover, kernel average misorientation (KAM) analysis was performed to evaluate the level of stored energy in the as-welded state. The results showed that the growth kinetics of the IM layer was not governed by a parabolic diffusion law. Presence of the IM compounds as well as high stored energy near the joint interface of the as-welded sample was recognized to be the origin of the observed deviation from the parabolic diffusion law. - Highlights: This work provided a new insight into growth kinetics of AlFe IM thickness. The growth kinetics of IM layer was not governed by a parabolic diffusion law. IM near the joint interface was the origin of deviation from the parabolic law. High stored energy at joint interface was origin of deviation from parabolic law.

  15. An Experimental and Chemical Kinetics Study of the Combustion of Syngas and High Hydrogen Content Fuels

    SciTech Connect (OSTI)

    Santoro, Robers; Dryer, Frederick; Ju, Yiguang

    2013-09-30

    An integrated and collaborative effort involving experiments and complementary chemical kinetic modeling investigated the effects of significant concentrations of water and CO2 and minor contaminant species (methane [CH4], ethane [C2H6], NOX, etc.) on the ignition and combustion of HHC fuels. The research effort specifically addressed broadening the experimental data base for ignition delay, burning rate, and oxidation kinetics at high pressures, and further refinement of chemical kinetic models so as to develop compositional specifications related to the above major and minor species. The foundation for the chemical kinetic modeling was the well validated mechanism for hydrogen and carbon monoxide developed over the last 25 years by Professor Frederick Dryer and his co-workers at Princeton University. This research furthered advance the understanding needed to develop practical guidelines for realistic composition limits and operating characteristics for HHC fuels. A suite of experiments was utilized that that involved a high-pressure laminar flow reactor, a pressure-release type high-pressure combustion chamber and a high-pressure turbulent flow reactor.

  16. Growth Kinetics and Modeling of Direct Oxynitride Growth with NO-O2 Gas Mixtures

    SciTech Connect (OSTI)

    Everist, Sarah; Nelson, Jerry; Sharangpani, Rahul; Smith, Paul Martin; Tay, Sing-Pin; Thakur, Randhir

    1999-05-03

    We have modeled growth kinetics of oxynitrides grown in NO-O2 gas mixtures from first principles using modified Deal-Grove equations. Retardation of oxygen diffusion through the nitrided dielectric was assumed to be the dominant growth-limiting step. The model was validated against experimentally obtained curves with good agreement. Excellent uniformity, which exceeded expected walues, was observed.

  17. Investigation of ion kinetic effects in direct-drive exploding-pusher implosions at the NIF

    SciTech Connect (OSTI)

    Rosenberg, M. J. Zylstra, A. B.; Séguin, F. H.; Rinderknecht, H. G.; Frenje, J. A.; Gatu Johnson, M.; Sio, H.; Waugh, C. J.; Sinenian, N.; Li, C. K.; Petrasso, R. D.; McKenty, P. W.; Hohenberger, M.; Radha, P. B.; Delettrez, J. A.; Glebov, V. Yu.; Betti, R.; Goncharov, V. N.; Knauer, J. P.; Sangster, T. C.; and others

    2014-12-15

    Measurements of yield, ion temperature, areal density (ρR), shell convergence, and bang time have been obtained in shock-driven, D{sub 2} and D{sup 3}He gas-filled “exploding-pusher” inertial confinement fusion (ICF) implosions at the National Ignition Facility to assess the impact of ion kinetic effects. These measurements probed the shock convergence phase of ICF implosions, a critical stage in hot-spot ignition experiments. The data complement previous studies of kinetic effects in shock-driven implosions. Ion temperature and fuel ρR inferred from fusion-product spectroscopy are used to estimate the ion-ion mean free path in the gas. A trend of decreasing yields relative to the predictions of 2D DRACO hydrodynamics simulations with increasing Knudsen number (the ratio of ion-ion mean free path to minimum shell radius) suggests that ion kinetic effects are increasingly impacting the hot fuel region, in general agreement with previous results. The long mean free path conditions giving rise to ion kinetic effects in the gas are often prevalent during the shock phase of both exploding pushers and ablatively driven implosions, including ignition-relevant implosions.

  18. Accelerating the Computation of Detailed Chemical Reaction Kinetics for Simulating Combustion of Complex Fuels

    SciTech Connect (OSTI)

    Grout, Ray W

    2012-01-01

    Combustion of hydrocarbon fuels has been a very challenging scientific and engineering problem due to the complexity of turbulent flows and hydrocarbon reaction kinetics. There is an urgent need to develop an efficient modeling capability to accurately predict the combustion of complex fuels. Detailed chemical kinetic models for the surrogates of fuels such as gasoline, diesel and JP-8 consist of thousands of chemical species and Arrhenius reaction steps. Oxygenated fuels such as bio-fuels and heavier hydrocarbons, such as from newer fossil fuel sources, are expected to have a much more complex chemistry requiring increasingly larger chemical kinetic models. Such models are beyond current computational capability, except for homogeneous or partially stirred reactor type calculations. The advent of highly parallel multi-core processors and graphical processing units (GPUs) promises a steep increase in computational performance in the coming years. This paper will present a software framework that translates the detailed chemical kinetic models to high- performance code targeted for GPU accelerators.

  19. The transfer between electron bulk kinetic energy and thermal energy in collisionless magnetic reconnection

    SciTech Connect (OSTI)

    Lu, San; Lu, Quanming; Huang, Can; Wang, Shui

    2013-06-15

    By performing two-dimensional particle-in-cell simulations, we investigate the transfer between electron bulk kinetic and electron thermal energy in collisionless magnetic reconnection. In the vicinity of the X line, the electron bulk kinetic energy density is much larger than the electron thermal energy density. The evolution of the electron bulk kinetic energy is mainly determined by the work done by the electric field force and electron pressure gradient force. The work done by the electron gradient pressure force in the vicinity of the X line is changed to the electron enthalpy flux. In the magnetic island, the electron enthalpy flux is transferred to the electron thermal energy due to the compressibility of the plasma in the magnetic island. The compression of the plasma in the magnetic island is the consequence of the electromagnetic force acting on the plasma as the magnetic field lines release their tension after being reconnected. Therefore, we can observe that in the magnetic island the electron thermal energy density is much larger than the electron bulk kinetic energy density.

  20. Comparisons of dense-plasma-focus kinetic simulations with experimental measurements

    SciTech Connect (OSTI)

    Schmidt, A.; Link, A.; Welch, D.; Ellsworth, J.; Falabella, S.; Tang, V.

    2014-06-01

    Dense-plasma-focus (DPF) Z-pinch devices are sources of copious high-energy electrons and ions, x rays, and neutrons. The mechanisms through which these physically simple devices generate such high-energy beams in a relatively short distance are not fully understood and past optimization efforts of these devices have been largely empirical. Previously we reported on fully kinetic simulations of a DPF and compared them with hybrid and fluid simulations of the same device. Here we present detailed comparisons between fully kinetic simulations and experimental data on a 1.2 kJ DPF with two electrode geometries, including neutron yield and ion beam energy distributions. A more intensive third calculation is presented which examines the effects of a fully detailed pulsed power driver model. We also compare simulated electromagnetic fluctuations with direct measurement of radiofrequency electromagnetic fluctuations in a DPF plasma. These comparisons indicate that the fully kinetic model captures the essential physics of these plasmas with high fidelity, and provide further evidence that anomalous resistivity in the plasma arises due to a kinetic instability near the lower hybrid frequency.

  1. Femtosecond laser pulse driven melting in gold nanorod aqueous colloidal suspension: Identification of a transition from stretched to exponential kinetics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Li, Yuelin; Jiang, Zhang; Lin, Xiao -Min; Wen, Haidan; Walko, Donald A.; Deshmukh, Sanket A.; Subbaraman, Ram; Sankaranarayanan, Subramanian K. R. S.; Gray, Stephen K.; Ho, Phay

    2015-01-30

    Many potential industrial, medical, and environmental applications of metal nanorods rely on the physics and resultant kinetics and dynamics of the interaction of these particles with light. We report a surprising kinetics transition in the global melting of femtosecond laser-driven gold nanorod aqueous colloidal suspension. At low laser intensity, the melting exhibits a stretched exponential kinetics, which abruptly transforms into a compressed exponential kinetics when the laser intensity is raised. It is found the relative formation and reduction rate of intermediate shapes play a key role in the transition. Supported by both molecular dynamics simulations and a kinetic model, themore » behavior is traced back to the persistent heterogeneous nature of the shape dependence of the energy uptake, dissipation and melting of individual nanoparticles. These results could have significant implications for various applications such as water purification and electrolytes for energy storage that involve heat transport between metal nanorod ensembles and surrounding solvents.« less

  2. Iron oxidation kinetics for H-2 and CO production via chemical looping

    SciTech Connect (OSTI)

    Stehle, RC; Bobek, MM; Hahn, DW

    2015-01-30

    Solar driven production of fuels by means of an intermediate reactive metal for species splitting has provided a practical and potentially efficient pathway for disassociating molecules at significantly lower thermal energies. The fuels of interest are of or derive from the separation of oxygen from H2O and CO2 to form hydrogen and carbon monoxide, respectively. The following study focuses on iron oxidation through water and CO2 splitting to explore the fundamental reaction kinetics and kinetic rates that are relevant to these processes. In order to properly characterize the reactive metal potential and to optimize a scaled-up solar reactor system, a monolith-based laboratory reactor was implemented to investigate reaction temperatures over a range from 990 to 1400 K. The presence of a single, solid monolith as a reacting surface allowed for a limitation in mass transport effects in order to monitor kinetically driven reaction steps. The formation of oxide layers on the iron monoliths followed Cabrera-Mott models for oxidation of metals with kinetic rates being measured using real-time mass spectrometry to calculate kinetic constants and estimate oxide layer thicknesses. Activation energies of 47.3 kJ/mol and 32.8 kJ/mol were found for water-splitting and CO2 splitting, respectively, and the conclusions of the independent oxidation reactions where applied to experimental results for syngas (H-2-CO) production to explore ideal process characteristics. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  3. Astrophysical Gyrokinetics: Kinetic and Fluid Turbulent Cascades In Magentized Weakly Collisional Plasmas

    SciTech Connect (OSTI)

    Schekochihin, A. A.; Cowley, S. C.; Dorland, W.; Hammett, G. W.; Howes, G. G.; Quataert, E.; Tatsuno, T.

    2009-04-23

    This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulentmotions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are that the turbulent fluctuations are small compared to the mean field, spatially anisotropic with respect to it and that their frequency is low compared to the ion cyclotron frequency. The turbulence is assumed to be forced at some system-specific outer scale. The energy injected at this scale has to be dissipated into heat, which ultimately cannot be accomplished without collisions. A kinetic cascade develops that brings the energy to collisional scales both in space and velocity. The nature of the kinetic cascade in various scale ranges depends on the physics of plasma fluctuations that exist there. There are four special scales that separate physically distinct regimes: the electron and ion gyroscales, the mean free path and the electron diffusion scale. In each of the scale ranges separated by these scales, the fully kinetic problem is systematically reduced to a more physically transparent and computationally tractable system of equations, which are derived in a rigorous way. In the "inertial range" above the ion gyroscale, the kinetic cascade separates into two parts: a cascade of Alfvenic fluctuations and a passive cascade of density and magnetic-fieldstrength fluctuations. The former are governed by the Reduced Magnetohydrodynamic (RMHD) equations at both the collisional and collisionless scales; the latter obey a linear kinetic equation along the (moving) field lines associated with the Alfvenic component (in the collisional limit, these compressive fluctuations become the slow and entropy modes of the conventional MHD). In the "dissipation range" below ion gyroscale, there are again two cascades: the kinetic-Alfven-wave (KAW) cascade governed by two fluid-like Electron Reduced Magnetohydrodynamic (ERMHD) equations and a passive cascade of ion entropy fluctuations both in space and velocity. The latter cascade brings the energy of the inertial-range fluctuations that was Landau-damped at the ion gyroscale to collisional scales in the phase space and leads to ion heating. The KAWenergy is similarly damped at the electron gyroscale and converted into electron heat. Kolmogorov-style scaling relations are derived for all of these cascades. The relationship between the theoretical models proposed in this paper and astrophysical applications and observations is discussed in detail.

  4. Kinetics of Methane Hydrate Decomposition Studied via in Situ Low Temperature X-ray Powder Diffraction

    SciTech Connect (OSTI)

    Everett, Susan M; Rawn, Claudia J; Keffer, David J.; Mull, Derek L; Payzant, E Andrew; Phelps, Tommy Joe

    2013-01-01

    Gas hydrates are known to have a slowed decomposition rate at ambient pressure and temperatures below the melting point of ice termed self-preservation or anomalous preservation. As hydrate exothermically decomposes, gas is released and water of the clathrate cages transforms into ice. Two regions of slowed decomposition for methane hydrate, 180 200 K and 230 260 K, were observed, and the kinetics were studied by in situ low temperature x-ray powder diffraction. The kinetic constants for ice formation from methane hydrate were determined by the Avrami model within each region and activation energies, Ea, were determined by the Arrhenius plot. Ea determined from the data for 180 200 K was 42 kJ/mol and for 230 260 K was 22 kJ/mol. The higher Ea in the colder temperature range was attributed to a difference in the microstructure of ice between the two regions.

  5. Geometrical investigation of the kinetic evolution of the magnetic field in a periodic flux rope

    SciTech Connect (OSTI)

    Restante, A. L.; Lapenta, G. [Afdeling Plasma-astrofysica, Departement Wiskunde, KULeuven, University of Leuven, Leuven (Belgium)] [Afdeling Plasma-astrofysica, Departement Wiskunde, KULeuven, University of Leuven, Leuven (Belgium); Markidis, S. [High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden)] [High Performance Computing and Visualization (HPCViz) Department, KTH Royal Institute of Technology, Stockholm (Sweden); Intrator, T. [Los Alamos National Laboratory, M.S. E526, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, M.S. E526, Los Alamos, New Mexico 87545 (United States)

    2013-08-15

    Flux ropes are bundles of magnetic field wrapped around an axis. Many laboratory, space, and astrophysics processes can be represented using this idealized concept. Here, a massively parallel 3D kinetic simulation of a periodic flux rope undergoing the kink instability is studied. The focus is on the topology of the magnetic field and its geometric structures. The analysis considers various techniques such as Poincar maps and the quasi-separatrix layer (QSL). These are used to highlight regions with expansion or compression and changes in the connectivity of magnetic field lines and consequently to outline regions where heating and current may be generated due to magnetic reconnection. The present study is, to our knowledge, the first QSL analysis of a fully kinetic 3D particle in cell simulation and focuses the existing QSL method of analysis to periodic systems.

  6. Detailed chemical kinetic mechanism for the oxidation of biodiesel fuels blend surrogate.

    SciTech Connect (OSTI)

    Herbinet, O; Pitz, W J; Westbrook, C K

    2009-07-21

    Detailed chemical kinetic mechanisms were developed and used to study the oxidation of two large unsaturated esters: methyl-5-decenoate and methyl-9-decenoate. These models were built from a previous methyl decanoate mechanism and were compared with rapeseed oil methyl esters oxidation experiments in a jet stirred reactor. A comparative study of the reactivity of these three oxygenated compounds was performed and the differences in the distribution of the products of the reaction were highlighted showing the influence of the presence and the position of a double bond in the chain. Blend surrogates, containing methyl decanoate, methyl-5-decenoate, methyl-9-decenoate and n-alkanes, were tested against rapeseed oil methyl esters and methyl palmitate/n-decane experiments. These surrogate models are realistic kinetic tools allowing the study of the combustion of biodiesel fuels in diesel and homogeneous charge compression ignition engines.

  7. Kinetics of elementary processes relevant to incipient soot formation. Final technical report

    SciTech Connect (OSTI)

    Lin, M.C.

    1998-03-09

    In order to better understand the mechanism of soot formation (one of the most challenging problems in the study of hydrocarbon combustion chemistry), reliable rate constants for the key reaction steps involved in the formation and polymerization of aromatic hydrocarbons in the inception stage are required for kinetic modeling. In this DOE sponsored work, the authors have developed three new experimental methods: cavity ring-down (CRD) spectrometry, pyrolysis/Fourier transform infrared spectrometry (p/FTIRS) and pulsed laser photolysis/mass spectrometry (PLP/MS) for kinetic measurements of C{sub 6}H{sub 5} reactions pivotal to incipient soot formation chemistry. In addition, the authors have also carried out ab initio molecular orbital (MO) calculations for several key elementary combustion reactions relevant to soot formation. The results are briefly summarized in the report using selected examples for more detailed discussion. 84 refs.

  8. HTP kinetics studies on isolated elementary combustion reactions over wide temperature ranges

    SciTech Connect (OSTI)

    Fontijn, A.; Adusei, G.Y.; Hranisavlevic, J.; Bajaj, P.N.

    1993-12-01

    The goals of this project are to provide accurate data on the temperature dependence of the kinetics of elementary combustion reactions, (i) for use by combustion modelers, and (ii) to gain a better fundamental understanding of, and hence predictive ability for, the chemistry involved. Experimental measurements are made mainly by using the pseudo-static HTP (high-temperature photochemistry) technique. While continuing rate coefficient measurements, further aspects of kinetics research are being explored. Thus, starting from the data obtained, a method for predicting the temperature dependence of rate coefficients of oxygen-atom olefin experiment and confirms the underlying mechanistic assumptions. Mechanistic information of another sort, i.e. by product analysis, has recently become accessible with the inauguration of our heated flow tube mass spectrometer facility; early results are reported here. HTP experiments designed to lead to measurements of product channels by resonance fluorescence have started.

  9. Detailed chemical kinetic mechanism for the oxidation of biodiesel fuels blend surrogate

    SciTech Connect (OSTI)

    Herbinet, Olivier; Pitz, William J.; Westbrook, Charles K.

    2010-05-15

    Detailed chemical kinetic mechanisms were developed and used to study the oxidation of two large unsaturated esters: methyl-5-decenoate and methyl-9-decenoate. These models were built from a previous methyl decanoate mechanism and were compared with rapeseed oil methyl esters oxidation experiments in a jet-stirred reactor. A comparative study of the reactivity of these three oxygenated compounds was performed and the differences in the distribution of the products of the reaction were highlighted showing the influence of the presence and the position of a double bond in the chain. Blend surrogates, containing methyl decanoate, methyl-5-decenoate, methyl-9-decenoate and n-alkanes, were tested against rapeseed oil methyl esters and methyl palmitate/n-decane experiments. These surrogate models are realistic kinetic tools allowing the study of the combustion of biodiesel fuels in diesel and homogeneous charge compression ignition engines. (author)

  10. Production of Biodiesel at Kinetic Limit Achieved in a Centrifugal Reactor/Separator

    SciTech Connect (OSTI)

    McFarlane, Joanna; Tsouris, Costas; Birdwell Jr, Joseph F; Lee, Denise L; Jennings, Hal L; Pahmer Boitrago, Amy M; Terpstra, Sarah M

    2010-01-01

    The kinetics of the transesterification of soybean oil has been investigated in a centrifugal reactor at temperatures from 45 to 80 C and pressures up to 2.6 bar using gas chromatography flame ionization detection (GC-FID) and infrared (IR) spectroscopy. The yields of product methyl esters were quantified using IR, proton Nuclear Magnetic Resonance (H1NMR), and viscosity measurements and were found to achieve 90% of the yield in 2 min; however, to meet ASTM specifications with one pass through the reactor, a 15 min residence time was needed. Performance was improved by sequential reactions, allowing separation of by-product glycerine and injection of additional small aliquots of methanol. The kinetics was modeled using a three-step mechanism of reversible reactions, which was used to predict performance at commercial scale. The mechanism correctly predicted the exponential decline in reaction rate as the concentration of the products allowed significant reverse reactions to occur.

  11. Kinetic performance of CO2 absorption into a potassium carbonate solution

    Office of Scientific and Technical Information (OSTI)

    promoted with the enzyme carbonic anhydrase: Comparison with a monoethanolamine solution (Journal Article) | SciTech Connect performance of CO2 absorption into a potassium carbonate solution promoted with the enzyme carbonic anhydrase: Comparison with a monoethanolamine solution Citation Details In-Document Search This content will become publicly available on May 24, 2017 Title: Kinetic performance of CO2 absorption into a potassium carbonate solution promoted with the enzyme carbonic

  12. Time-Resolved Small-Angle X-ray Scattering Studies Revealed Three Kinetic

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Stages of a T=4 Virus Maturation June 2010 Time-Resolved Small-Angle X-ray Scattering Studies Revealed Three Kinetic Stages of a T=4 Virus Maturation Most eukaryotic viruses, including HIV, influenza and herpes viruses, undergo maturation when transitioning from the noninfectious provirion to the infectious virion. Maturation processes involve reorganization of viral quaternary structure to defend viral gene from the cellular defense mechanism and lead to effective transfection. Nudaurelia

  13. Intercomparison of the seasonal cycle in 200 hPa kinetic energy in AMIP GCM simulations

    SciTech Connect (OSTI)

    Boyle, J.S.

    1996-10-01

    The 200 hPa kinetic energy is represented by means of the spherical harmonic components for the Atmospheric Model Intercomparison Project (AMIP) simulations, the National Center for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis and the European Centre for Medium Range Weather Forecast Reanalysis (ERA). The data used are the monthly mean wind fields from 1979 to 1988. The kinetic energy is decomposed into the divergent (DKE) and rotational (RKE) components and emphasis is placed on examining the former. The two reanalysis data sets show reasonable agreement that is best for the rotational kinetic energy. The largest difference in the divergent kinetic energy occurs during the northern summer. As might be expected, the two analyses are closet in regions where there are sufficient observations such that the effect of the model used in the assimilation cycle are minimized. The observed RKE show only a slight seasonal cycle with a maximum occuring during the northern winter. The DKE, on the other hand, has a very pronounced seasonal cycle with maxima at the solsticial seasons and minima during the equinoctial seasons. The model results show a very large spread in the magnitudes of the RKE and DKE although the models all evince a seasonal variation in phase with that observed. The median values of the seasonal cycle of RKE and DKE for the models are usually superior to those of any individual model. Results are also presented for simulation following the AMIP protocol but using updated versions of the original AMIP entries. In most cases these new integrations show better agreement with the observations.

  14. A thermodynamic and kinetic model for paste-aggregate interactions and

    Office of Scientific and Technical Information (OSTI)

    the alkali-silica reaction (Journal Article) | SciTech Connect This content will become publicly available on May 30, 2017 Title: A thermodynamic and kinetic model for paste-aggregate interactions and the alkali-silica reaction Authors: Guthrie, George D. ; Carey, J. William Publication Date: 2015-10-01 OSTI Identifier: 1246650 Type: Publisher's Accepted Manuscript Journal Name: Cement and Concrete Research Additional Journal Information: Journal Volume: 76; Journal Issue: C; Journal ID:

  15. Chemical Kinetic Reaction Mechanisms for Combustion of Hydrocarbon and Other Types of Chemical Fuels

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Reaction mechanisms have been tested and validated extensively through comparisons between computed results and measured data from laboratory experiments (e.g., shock tubes, laminar flames, rapid compression machines, flow reactors, stirred reactors) and from practical systems (e.g., diesel engines, spark-ignition engines, homogeneous charge, compression ignition (HCCI) engines). These kinetic models are used to examine a wide range of combustion systems.

  16. CLEERS Coordination & Joint Development of Benchmark Kinetics for LNT & SCR

    Broader source: Energy.gov (indexed) [DOE]

    | Department of Energy 2 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting PDF icon ace022_daw_2012_o.pdf More Documents & Publications CLEERS Coordination & Joint Development of Benchmark Kinetics for LNT & SCR Emissions Control for Lean Gasoline Engines NH3 generation over commercial Three-Way Catalysts and Lean-NOx Traps

  17. Kinetic Structure of the Electron Diffusion Region in Antiparallel Magnetic Reconnection

    SciTech Connect (OSTI)

    Ng, J.; Egedal, J.; Le, A.; Daughton, W.; Chen, L.-J.

    2011-02-11

    Strong electron pressure anisotropy has been observed upstream of electron diffusion regions during reconnection in Earth's magnetotail and kinetic simulations. For collisionless antiparallel reconnection, we find that the anisotropy drives the electron current in the electron diffusion region, and that this current is insensitive to the reconnection electric field. Reconstruction of the electron distribution function within this region at enhanced resolutions reveals its highly structured nature and the mechanism by which the pressure anisotropy sets the structure of the region.

  18. Nucleation of diindenoperylene and pentacene at thermal and hyperthermal incident kinetic energies

    SciTech Connect (OSTI)

    Kish, Edward R.; Desai, Tushar V.; Greer, Douglas R.; Engstrom, James R.; Woll, Arthur R.

    2015-05-15

    The authors have examined the nucleation of diindenoperylene (DIP) on SiO{sub 2} employing primarily atomic force microscopy and focusing on the effect of incident kinetic energy employing both thermal and supersonic sources. For all incident kinetic energies examined (E{sub i} = 0.09–11.3 eV), the nucleation of DIP is homogeneous and the dependence of the maximum island density on the growth rate is described by a power law. A critical nucleus of approximately two molecules is implicated by our data. A re-examination of the nucleation of pentacene on SiO{sub 2} gives the same major result that the maximum island density is determined by the growth rate, and it is independent of the incident kinetic energy. These observations are readily understood by factoring in the size of the critical nucleus in each case, and the island density, which indicates that diffusive transport of molecules to the growing islands dominate the dynamics of growth in the submonolayer regime.

  19. High-Pressure Turbulent Flame Speeds and Chemical Kinetics of Syngas Blends with and without Impurities

    SciTech Connect (OSTI)

    Peterson, Eric; Mathieu, Olivier; Morones, Anibal; Ravi, Sankar; Keesee, Charles; Hargis, Joshua; Vivanco, Jose

    2014-12-01

    This Topical Report documents the first year of the project, from October 1, 2013 through September 30, 2014. Efforts for this project included experiments to characterize the atmospheric-pressure turbulent flame speed vessel over a range of operating conditions (fan speeds and turbulent length scales). To this end, a new LDV system was acquired and set up for the detailed characterization of the turbulence field. Much progress was made in the area of impurity kinetics, which included a numerical study of the effect of impurities such as NO2, NO, H2S, and NH3 on ignition delay times and laminar flame speeds of syngas blends at engine conditions. Experiments included a series of laminar flame speed measurements for syngas (CO/H2) blends with various levels of CH4 and C2H6 addition, and the results were compared to the chemical kinetics model of NUI Galway. Also, a final NOx kinetics mechanism including ammonia was assembled, and a journal paper was written and is now in press. Overall, three journal papers and six conference papers related to this project were published this year. Finally, much progress was made on the design of the new high-pressure turbulent flame speed facility. An overall design that includes a venting system was decided upon, and the detailed design is in progress.

  20. Kinetics of Chronic Oxidation of NBG-17 Nuclear Graphite by Water Vapor

    SciTech Connect (OSTI)

    Contescu, Cristian I; Burchell, Timothy D; Mee, Robert

    2015-05-01

    This report presents the results of kinetic measurements during accelerated oxidation tests of NBG-17 nuclear graphite by low concentration of water vapor and hydrogen in ultra-high purity helium. The objective is to determine the parameters in the Langmuir-Hinshelwood (L-H) equation describing the oxidation kinetics of nuclear graphite in the helium coolant of high temperature gas-cooled reactors (HTGR). Although the helium coolant chemistry is strictly controlled during normal operating conditions, trace amounts of moisture (predictably < 0.2 ppm) cannot be avoided. Prolonged exposure of graphite components to water vapor at high temperature will cause very slow (chronic) oxidation over the lifetime of graphite components. This behavior must be understood and predicted for the design and safe operation of gas-cooled nuclear reactors. The results reported here show that, in general, oxidation by water of graphite NBG-17 obeys the L-H mechanism, previously documented for other graphite grades. However, the characteristic kinetic parameters that best describe oxidation rates measured for graphite NBG-17 are different than those reported previously for grades H-451 (General Atomics, 1978) and PCEA (ORNL, 2013). In some specific conditions, certain deviations from the generally accepted L-H model were observed for graphite NBG-17. This graphite is manufactured in Germany by SGL Carbon Group and is a possible candidate for the fuel elements and reflector blocks of HTGR.

  1. Kinetics Study of Solid Ammonia Borane Hydrogen Release Modeling and Experimental Validation for Chemical Hydrogen Storage

    SciTech Connect (OSTI)

    Choi, Yong-Joon; Ronnebro, Ewa; Rassat, Scot D.; Karkamkar, Abhijeet J.; Maupin, Gary D.; Holladay, Jamelyn D.; Simmons, Kevin L.; Brooks, Kriston P.

    2014-02-24

    Ammonia borane (AB), NH3BH3, is a promising material for chemical hydrogen storage with 19.6 wt% gravimetric hydrogen capacity of which 16.2 wt% hydrogen can be utilized below 200C. We have investigated the kinetics of hydrogen release from AB and from an AB-methyl cellulose (AB/MC) composite at temperatures of 160-300C using both experiments and modeling. The purpose of our study was to show safe hydrogen release without thermal runaway effects and to validate system model kinetics. AB/MC released hydrogen at ~20C lower than neat AB and at a rate that is two times faster. Based on the experimental results, the kinetics equations were revised to better represent the growth and nucleation process during decomposition of AB. We explored two different reactor concepts; Auger and fixed bed. The current Auger reactor concept turned out to not be appropriate, however, we demonstrated safe self-propagation of the hydrogen release reaction of solid AB/MC in a fixed bed reactor.

  2. Kinetics of ion and prompt electron emission from laser-produced plasma

    SciTech Connect (OSTI)

    Farid, N. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States) [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China); Harilal, S. S.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Ding, H. [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)] [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)

    2013-07-15

    We investigated ion emission dynamics of laser-produced plasma from several elements, comprised of metals and non-metals (C, Al, Si, Cu, Mo, Ta, W), under vacuum conditions using a Faraday cup. The estimated ion flux for various targets studied showed a decreasing tendency with increasing atomic mass. For metals, the ion flux is found to be a function of sublimation energy. A comparison of temporal ion profiles of various materials showed only high-Z elements exhibited multiple structures in the ion time of flight profile indicated by the observation of higher peak kinetic energies, which were absent for low-Z element targets. The slower ions were seen regardless of the atomic number of target material propagated with a kinetic energy of 15 keV, while the fast ions observed in high-Z materials possessed significantly higher energies. A systematic study of plasma properties employing fast photography, time, and space resolved optical emission spectroscopy, and electron analysis showed that there existed different mechanisms for generating ions in laser ablation plumes. The origin of high kinetic energy ions is related to prompt electron emission from high-Z targets.

  3. Hydrogen-bond driven loop-closure kinetics in unfolded polypeptide chains

    SciTech Connect (OSTI)

    Daidone, Isabella [University of Heidelberg; Neuweiler, H [University of Heidelberg; Doose, S [University of Heidelberg; Sauer, M [University of Heidelberg; Smith, Jeremy C [ORNL

    2010-12-01

    Characterization of the length dependence of end-to-end loop-closure kinetics in unfolded polypeptide chains provides an understanding of early steps in protein folding. Here, loop-closure in poly-glycine-serine peptides is investigated by combining single-molecule fluorescence spectroscopy with molecular dynamics simulation. For chains containing more than 10 peptide bonds loop-closing rate constants on the 20-100 nanosecond time range exhibit a power-law length dependence. However, this scaling breaks down for shorter peptides, which exhibit slower kinetics arising from a perturbation induced by the dye reporter system used in the experimental setup. The loop-closure kinetics in the longer peptides is found to be determined by the formation of intra-peptide hydrogen bonds and transient beta-sheet structure, that accelerate the search for contacts among residues distant in sequence relative to the case of a polypeptide chain in which hydrogen bonds cannot form. Hydrogen-bond-driven polypeptide-chain collapse in unfolded peptides under physiological conditions found here is not only consistent with hierarchical models of protein folding, that highlights the importance of secondary structure formation early in the folding process, but is also shown to speed up the search for productive folding events.

  4. Kinetic mix mechanisms in shock-driven inertial confinement fusion implosions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rinderknecht, H. G.; Sio, H.; Li, C. K.; Hoffman, N.; Zylstra, A. B.; Rosenberg, M. J.; Frenje, J. A.; Gatu Johnson, M.; Seguin, F. H.; Petrasso, R. D.; et al

    2014-05-19

    Shock-driven implosions of thin-shell capsules, or ''exploding pushers,'' generate low-density, high-temperature plasmas in which hydrodynamic instability growth is negligible and kinetic effects can play an important role. Data from implosions of thin deuterated-plastic shells with hydroequivalent D3He gas fills ranging from pure deuterium to pure 3He [H. G. Rinderknecht et al., Phys. Rev. Lett. 112, 135001 (2014)] were obtained to evaluate non-hydrodynamic fuel-shell mix mechanisms. Simulations of the experiments including reduced ion kinetic models support ion diffusion as an explanation for these data. Several additional kinetic mechanisms are investigated and compared to the data to determine which are important inmore » the experiments. Shock acceleration of shell deuterons is estimated to introduce mix less than or comparable to the amount required to explain the data. Beam-target mechanisms are found to produce yields at most an order of magnitude less than the observations« less

  5. The Autoignition of iso-Cetane: Shock Tube Experiments and Kinetic Modeling

    SciTech Connect (OSTI)

    Oehlschlaeger, M A; Steinberg, J; Westbrook, C K; Pitz, W J

    2009-02-25

    Iso-cetane (2,2,4,4,6,8,8-heptamethylnonane, C{sub 16}H{sub 34}) is a highly branched alkane reference compound for determining cetane ratings. It is also a candidate branched alkane representative in surrogate mixtures for diesel and jet fuels. Here new experiments and kinetic modeling results are presented for the autoignition of iso-cetane at elevated temperatures and pressures relevant to combustion in internal combustion engines. Ignition delay time measurements were made in reflected shock experiments in a heated shock tube for {Phi} = 0.5 and 1.0 iso-cetane/air mixtures at temperatures ranging from 953 to 1347 K and pressures from 8 to 47 atm. Ignition delay times were measured using electronically excited OH emission, monitored through the shock tube end wall, and piezoelectric pressure transducer measurements, made at side wall locations. A new kinetic mechanism for the description of the oxidation of iso-cetane is presented that is developed based on a previous mechanism for iso-octane. Computed results from the mechanism are found in good agreement with the experimental measurements. To our knowledge, the ignition time measurements and detailed kinetic mechanism for isocetane presented here are the first of their kind.

  6. The Role of Comprehensive Detailed Chemical Kinetic Reaction Mechanisms in Combustion Research

    SciTech Connect (OSTI)

    Westbrook, C K; Pitz, W J; Curran, H J; Mehl, M

    2008-07-16

    Recent developments by the authors in the field of comprehensive detailed chemical kinetic reaction mechanisms for hydrocarbon fuels are reviewed. Examples are given of how these mechanisms provide fundamental chemical insights into a range of combustion applications. Practical combustion consists primarily of chemical heat release from reactions between a fuel and an oxidizer, and computer simulations of practical combustion systems have become an essential tool of combustion research (Westbrook et al., 2005). At the heart of most combustion simulations, the chemical kinetic submodel frequently is the most detailed, complex and computationally costly part of a system model. Historically, the chemical submodel equations are solved using time-implicit numerical algorithms, due to the extreme stiffness of the coupled rate equations, with a computational cost that varies roughly with the cube of the number of chemical species in the model. While early mechanisms (c. 1980) for apparently simple fuels such as methane (Warnatz, 1980) or methanol (Westbrook and Dryer, 1979) included perhaps 25 species, current detailed mechanisms for much larger, more complex fuels such as hexadecane (Fournet et al., 2001; Ristori et al., 2001; Westbrook et al., 2008) or methyl ester methyl decanoate (Herbinet et al., 2008) have as many as 2000 or even 3000 species. Rapid growth in capabilities of modern computers has been an essential feature in this rapid growth in the size and complexity of chemical kinetic reaction mechanisms.

  7. Kinetic electron and ion instability of the lunar wake simulated at physical mass ratio

    SciTech Connect (OSTI)

    Haakonsen, Christian Bernt Hutchinson, Ian H. Zhou, Chuteng

    2015-03-15

    The solar wind wake behind the moon is studied with 1D electrostatic particle-in-cell (PIC) simulations using a physical ion to electron mass ratio (unlike prior investigations); the simulations also apply more generally to supersonic flow of dense magnetized plasma past non-magnetic objects. A hybrid electrostatic Boltzmann electron treatment is first used to investigate the ion stability in the absence of kinetic electron effects, showing that the ions are two-stream unstable for downstream wake distances (in lunar radii) greater than about three times the solar wind Mach number. Simulations with PIC electrons are then used to show that kinetic electron effects can lead to disruption of the ion beams at least three times closer to the moon than in the hybrid simulations. This disruption occurs as the result of a novel wake phenomenon: the non-linear growth of electron holes spawned from a narrow dimple in the electron velocity distribution. Most of the holes arising from the dimple are small and quickly leave the wake, approximately following the unperturbed electron phase-space trajectories, but some holes originating near the center of the wake remain and grow large enough to trigger disruption of the ion beams. Non-linear kinetic-electron effects are therefore essential to a comprehensive understanding of the 1D electrostatic stability of such wakes, and possible observational signatures in ARTEMIS data from the lunar wake are discussed.

  8. Kinetic mix mechanisms in shock-driven inertial confinement fusion implosions

    SciTech Connect (OSTI)

    Rinderknecht, H. G.; Sio, H.; Li, C. K.; Hoffman, N.; Zylstra, A. B.; Rosenberg, M. J.; Frenje, J. A.; Gatu Johnson, M.; Seguin, F. H.; Petrasso, R. D.; Betti, R.; Yu Glebov, V.; Meyerhofer, D. D.; Sangster, T. C.; Seka, W.; Stoeckl, C.; Kagan, G.; Molvig, K.; Bellei, C.; Amendt, P.; Landen, O.; Rygg, J. R.; Smalyuk, V. A.; Wilks, S.; Greenwood, A.; Nikroo, A.

    2014-05-19

    Shock-driven implosions of thin-shell capsules, or ''exploding pushers,'' generate low-density, high-temperature plasmas in which hydrodynamic instability growth is negligible and kinetic effects can play an important role. Data from implosions of thin deuterated-plastic shells with hydroequivalent D3He gas fills ranging from pure deuterium to pure 3He [H. G. Rinderknecht et al., Phys. Rev. Lett. 112, 135001 (2014)] were obtained to evaluate non-hydrodynamic fuel-shell mix mechanisms. Simulations of the experiments including reduced ion kinetic models support ion diffusion as an explanation for these data. Several additional kinetic mechanisms are investigated and compared to the data to determine which are important in the experiments. Shock acceleration of shell deuterons is estimated to introduce mix less than or comparable to the amount required to explain the data. Beam-target mechanisms are found to produce yields at most an order of magnitude less than the observations

  9. Analyzing and modeling the kinetics of amyloid beta pores associated with Alzheimer’s disease pathology

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ullah, Ghanim; Demuro, Angelo; Parker, Ian; Pearson, John E.; Xu, Shang -Zhong

    2015-09-08

    Amyloid beta (Aβ) oligomers associated with Alzheimer’s disease (AD) form Ca2+-permeable plasma membrane pores, leading to a disruption of the otherwise well-controlled intracellular calcium (Ca2+) homeostasis. The resultant up-regulation of intracellular Ca2+ concentration has detrimental implications for memory formation and cell survival. The gating kinetics and Ca2+ permeability of Aβ pores are not well understood. We have used computational modeling in conjunction with the ability of optical patch-clamping for massively parallel imaging of Ca2+ flux through thousands of pores in the cell membrane of Xenopus oocytes to elucidate the kinetic properties of Aβ pores. The fluorescence time-series data from individualmore » pores were idealized and used to develop data-driven Markov chain models for the kinetics of the Aβ pore at different stages of its evolution. Our study provides the first demonstration of developing Markov chain models for ion channel gating that are driven by optical-patch clamp data with the advantage of experiments being performed under close to physiological conditions. As a result, we demonstrate the up-regulation of gating of various Ca2+ release channels due to Aβ pores and show that the extent and spatial range of such up-regulation increases as Aβ pores with low open probability and Ca2+ permeability transition into those with high open probability and Ca2+ permeability.« less

  10. Kinetic and mechanistic studies of free-radical reactions in combustion

    SciTech Connect (OSTI)

    Tully, F.P.

    1993-12-01

    Combustion is driven by energy-releasing chemical reactions. Free radicals that participate in chain reactions carry the combustion process from reactants to products. Research in chemical kinetics enables us to understand the microscopic mechanisms involved in individual chemical reactions as well as to determine the rates at which they proceed. Both types of information are required for an understanding of how flames burn, why engines knock, how to minimize the production of pollutants, and many other important questions in combustion. In this program the authors emphasize accurate measurements over wide temperature ranges of the rates at which ubiquitous free radicals react with stable molecules. The authors investigate a variety of OH, CN, and CH + stable molecule reactions important to fuel conversion, emphasizing application of the extraordinarily precise technique of laser photolysis/continuous-wave laser-induced fluorescence (LP/cwLIF). This precision enables kinetic measurements to serve as mechanistic probes. Since considerable effort is required to study each individual reaction, prudent selection is critical. Two factors encourage selection of a specific reaction: (1) the rates and mechanisms of the subject reaction are required input to a combustion model; and (2) the reaction is a chemical prototype which, upon characterization, will provide fundamental insight into chemical reactivity, facilitate estimation of kinetic parameters for similar reactions, and constrain and test the computational limits of reaction-rate theory. Most studies performed in this project satisfy both conditions.

  11. Kinetic gating mechanism of DNA damage recognition by Rad4/XPC

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, Xuejing; Velmurugu, Yogambigai; Zheng, Guanqun; Park, Beomseok; Shim, Yoonjung; Kim, Youngchang; Liu, Lili; Van Houten, Bennett; He, Chuan; Ansari, Anjum; et al

    2015-01-06

    The xeroderma pigmentosum C (XPC) complex initiates nucleotide excision repair by recognizing DNA lesions before recruiting downstream factors. How XPC detects structurally diverse lesions embedded within normal DNA is unknown. Here we present a crystal structure that captures the yeast XPC orthologue (Rad4) on a single register of undamaged DNA. The structure shows that a disulphide-tethered Rad4 flips out normal nucleotides and adopts a conformations similar to that seen with damaged DNA. Contrary to many DNA repair enzymes that can directly reject non-target sites as structural misfits, our results suggest that Rad4/XPC uses a kinetic gating mechanism whereby lesion selectivitymore » arises from the kinetic competition between DNA opening and the residence time of Rad4/XPC per site. This mechanism is further supported by measurements of Rad4-induced lesion-opening times using temperature-jump pertubation spectroscopy. Kinetic gating may be a general mechanism used by site-specific DNA-binding proteins to minimize time-consuming interrogations of non-target sites.« less

  12. Measuring kinetic energy changes in the mesoscale with low acquisition rates

    SciTech Connect (OSTI)

    Roldn, .; Martnez, I. A.; Rica, R. A.; Dinis, L.

    2014-06-09

    We report on the measurement of the average kinetic energy changes in isothermal and non-isothermal quasistatic processes in the mesoscale, realized with a Brownian particle trapped with optical tweezers. Our estimation of the kinetic energy change allows to access to the full energetic description of the Brownian particle. Kinetic energy estimates are obtained from measurements of the mean square velocity of the trapped bead sampled at frequencies several orders of magnitude smaller than the momentum relaxation frequency. The velocity is tuned applying a noisy electric field that modulates the amplitude of the fluctuations of the position and velocity of the Brownian particle, whose motion is equivalent to that of a particle in a higher temperature reservoir. Additionally, we show that the dependence of the variance of the time-averaged velocity on the sampling frequency can be used to quantify properties of the electrophoretic mobility of a charged colloid. Our method could be applied to detect temperature gradients in inhomogeneous media and to characterize the complete thermodynamics of biological motors and of artificial micro and nanoscopic heat engines.

  13. Development of Kinetic Models for the Liquid Phase Methanol (LPMEOH tm) Process

    SciTech Connect (OSTI)

    Xiang-Dong Peng

    2002-06-01

    This report covers our recent work on the kinetics of the LPMEOH{trademark} process. The major part of the report concerns the development of more robust kinetic models for the LPMEOH{trademark} reaction system. The development was needed to meet the requirements for more accurate process simulations over a wide range of conditions. To this end, kinetic experiments were designed based on commercial needs and a D-Optimal design package. A database covering 53 different conditions was built. Two new reactions were identified and added to the LPMEOH{trademark} reaction network. New rate models were developed for all 15 reactions in the system. The new rate models are more robust than the original ones, showing better fit to the experimental results over a wide range of conditions. Related to this model development are some new understandings about the sensitivity of rate models and their effects on catalyst life study. The last section of this report covers a separate topic: water injection to the LPMEOH{trademark} reactor and its effects on the LPMEOH{trademark} process. An investigation was made of whether water injection can enhance the reactor productivity and how this enhancement depends on the composition of the major syngas feed. A water injection condition that resulted in 32% enhancement in productivity was observed. A catalyst life test under this water injection condition was conducted and showed no negative effects of water injection on catalyst stability.

  14. High-order continuum kinetic method for modeling plasma dynamics in phase space

    SciTech Connect (OSTI)

    Vogman, G. V.; Colella, P.; Shumlak, U.

    2014-12-15

    Continuum methods offer a high-fidelity means of simulating plasma kinetics. While computationally intensive, these methods are advantageous because they can be cast in conservation-law form, are not susceptible to noise, and can be implemented using high-order numerical methods. Advances in continuum method capabilities for modeling kinetic phenomena in plasmas require the development of validation tools in higher dimensional phase space and an ability to handle non-cartesian geometries. To that end, a new benchmark for validating Vlasov-Poisson simulations in 3D (x,vx,vy) is presented. The benchmark is based on the Dory-Guest-Harris instability and is successfully used to validate a continuum finite volume algorithm. To address challenges associated with non-cartesian geometries, unique features of cylindrical phase space coordinates are described. Preliminary results of continuum kinetic simulations in 4D (r,z,vr,vz) phase space are presented.

  15. Role of filament annealing in the kinetics and thermodynamics of nucleated polymerization

    SciTech Connect (OSTI)

    Michaels, Thomas C. T.; Knowles, Tuomas P. J.

    2014-06-07

    The formation of nanoscale protein filaments from soluble precursor molecules through nucleated polymerization is a common form of supra-molecular assembly phenomenon. This process underlies the generation of a range of both functional and pathological structures in nature. Filament breakage has emerged as a key process controlling the kinetics of the growth reaction since it increases the number of filament ends in the system that can act as growth sites. In order to ensure microscopic reversibility, however, the inverse process of fragmentation, end-to-end annealing of filaments, is a necessary component of a consistent description of such systems. Here, we combine Smoluchowski kinetics with nucleated polymerization models to generate a master equation description of protein fibrillization, where filamentous structures can undergo end-to-end association, in addition to elongation, fragmentation, and nucleation processes. We obtain self-consistent closed-form expressions for the growth kinetics and discuss the key physics that emerges from considering filament fusion relative to current fragmentation only models. Furthermore, we study the key time scales that describe relaxation to equilibrium.

  16. Combustion Kinetics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nuclear Fuel Cycle Defense Waste Management Programs ... creating the first internal combustion engines, chemists ... need to know any chemistry beyond fuel + air heat ...

  17. Enhanced Generic Phase-field Model of Irradiation Materials: Fission Gas Bubble Growth Kinetics in Polycrystalline UO2

    SciTech Connect (OSTI)

    Li, Yulan; Hu, Shenyang Y.; Montgomery, Robert O.; Gao, Fei; Sun, Xin

    2012-05-30

    Experiments show that inter-granular and intra-granular gas bubbles have different growth kinetics which results in heterogeneous gas bubble microstructures in irradiated nuclear fuels. A science-based model predicting the heterogeneous microstructure evolution kinetics is desired, which enables one to study the effect of thermodynamic and kinetic properties of the system on gas bubble microstructure evolution kinetics and morphology, improve the understanding of the formation mechanisms of heterogeneous gas bubble microstructure, and provide the microstructure to macroscale approaches to study their impact on thermo-mechanical properties such as thermo-conductivity, gas release, volume swelling, and cracking. In our previous report 'Mesoscale Benchmark Demonstration, Problem 1: Mesoscale Simulations of Intra-granular Fission Gas Bubbles in UO2 under Post-irradiation Thermal Annealing', we developed a phase-field model to simulate the intra-granular gas bubble evolution in a single crystal during post-irradiation thermal annealing. In this work, we enhanced the model by incorporating thermodynamic and kinetic properties at grain boundaries, which can be obtained from atomistic simulations, to simulate fission gas bubble growth kinetics in polycrystalline UO2 fuels. The model takes into account of gas atom and vacancy diffusion, vacancy trapping and emission at defects, gas atom absorption and resolution at gas bubbles, internal pressure in gas bubbles, elastic interaction between defects and gas bubbles, and the difference of thermodynamic and kinetic properties in matrix and grain boundaries. We applied the model to simulate gas atom segregation at grain boundaries and the effect of interfacial energy and gas mobility on gas bubble morphology and growth kinetics in a bi-crystal UO2 during post-irradiation thermal annealing. The preliminary results demonstrate that the model can produce the equilibrium thermodynamic properties and the morphology of gas bubbles at grain boundaries for given grain boundary properties. More validation of the model capability in polycrystalline is underway.

  18. Evaluation of a hybrid kinetics/mixing-controlled combustion model for turbulent premixed and diffusion combustion using KIVA-2

    SciTech Connect (OSTI)

    Nguyen, H.L.; Wey, Mingjyh.

    1990-01-01

    Two dimensional calculations were made of spark ignited premixed-charge combustion and direct injection stratified-charge combustion in gasoline fueled piston engines. Results are obtained using kinetic-controlled combustion submodel governed by a four-step global chemical reaction or a hybrid laminar kinetics/mixing-controlled combustion submodel that accounts for laminar kinetics and turbulent mixing effects. The numerical solutions are obtained by using KIVA-2 computer code which uses a kinetic-controlled combustion submodel governed by a four-step global chemical reaction (i.e., it assumes that the mixing time is smaller than the chemistry). A hybrid laminar/mixing-controlled combustion submodel was implemented into KIVA-2. In this model, chemical species approach their thermodynamics equilibrium with a rate that is a combination of the turbulent-mixing time and the chemical-kinetics time. The combination is formed in such a way that the longer of the two times has more influence on the conversion rate and the energy release. An additional element of the model is that the laminar-flame kinetics strongly influence the early flame development following ignition.

  19. COS-forming reaction between CO and sulfur: A high-temperature intrinsic kinetics study

    SciTech Connect (OSTI)

    Karan, K.; Mehrotra, A.K.; Behie, L.A. [Univ. of Calgary, Alberta (Canada). Dept. of Chemical and Petroleum Engineering] [Univ. of Calgary, Alberta (Canada). Dept. of Chemical and Petroleum Engineering

    1998-12-01

    Carbonyl sulfide is formed in the front end (i.e., the reaction furnace and the waste heat boiler) of Claus plants which are commonly used to recover sulfur from acid gases. Moreover, COS along with CS{sub 2}, are recognized as the problematic sulfur compounds that contribute significantly to plant sulfur emissions. Further, there is limited kinetic information on the important reaction for the formation of these two compounds. Now, it is well-known that one of the important COS-forming reactions is that between CO and sulfur. In this laboratory, the authors conducted an experimental study to measure the intrinsic kinetics of this homogeneous gas-phase reaction in the temperature range of 600--1150 C and over a residence time of 0.5--2.0 s. The overall reaction was found to be second order with a reaction rate constant k{sub f} = (3.18 {+-} 0.36) {times} 10{sup 5} exp[{minus}(6700 {+-} 108 K)/T] m{sup 3}/(kmol{center_dot}s). In addition, a kinetic model was developed to account for both the COS formation and the COS decomposition reactions. And, finally, for the reverse reaction, the COS decomposition reaction rate constant (k{sub r}) was regressed to match the equilibrium data of experiments at high temperatures giving a second-order reaction rate constant as k{sub r} = (2.18 {+-} 1.12) {times} 10{sup 9} exp[{minus}(21630 {+-} 160 K)/T] m{sup 3}/(kmol{center_dot}s).

  20. Conditions for critical effects in the mass action kinetics equations for water radiolysis

    SciTech Connect (OSTI)

    Wittman, Richard S.; Buck, Edgar C.; Mausolf, Edward J.; McNamara, Bruce K.; Smith, Frances N.; Soderquist, Chuck Z.

    2014-12-26

    We report on a subtle global feature of the mass action kinetics equations for water radiolysis that results in predictions of a critical behavior in H2O2 and associated radical concentrations. While radiolysis kinetics has been studied extensively in the past, it is only in recent years that high speed computing has allowed the rapid exploration of the solution over widely varying dose and compositional conditions. We explore the radiolytic production of H2O2 under various externally fixed conditions of molecular H2 and O2 that have been regarded as problematic in the literature specifically, jumps in predicted concentrations, and inconsistencies between predictions and experiments have been reported for alpha radiolysis. We computationally map-out a critical concentration behavior for alpha radiolysis kinetics using a comprehensive set of reactions. We then show that all features of interest are accurately reproduced with 15 reactions. An analytical solution for steady-state concentrations of the 15 reactions reveals regions in [H2] and [O2] where the H2O2 concentration is not unique both stable and unstable concentrations exist. The boundary of this region can be characterized analytically as a function of G-values and rate constants independent of dose rate. Physically, the boundary can be understood as separating a region where a steady-state H2O2 concentration exists, from one where it does not exist without a direct decomposition reaction. We show that this behavior is consistent with reported alpha radiolysis data and that no such behavior should occur for gamma radiolysis. We suggest experiments that could verify or discredit a critical concentration behavior for alpha radiolysis and could place more restrictive ranges on G-values from derived relationships between them.

  1. Conditions for critical effects in the mass action kinetics equations for water radiolysis

    SciTech Connect (OSTI)

    Wittman, Richard S.; Buck, Edgar C.; Mausolf, Edward J.; McNamara, Bruce K.; Smith, Frances N.; Soderquist, Chuck Z.

    2014-11-25

    We report on a subtle global feature of the mass action kinetics equations for water radiolysis that results in predictions of a critical behavior in H2O2 and associated radical concentrations. While radiolysis kinetics has been studied extensively in the past, it is only in recent years that high speed computing has allowed the rapid exploration of the solution over widely varying dose and compositional conditions. We explore the radiolytic production of H2O2 under various externally fixed conditions of molecular H2 and O2 that have been regarded as problematic in the literature specifically, jumps in predicted concentrations, and inconsistencies between predictions and experiments have been reported for alpha radiolysis. We computationally map-out a critical concentration behavior for alpha radiolysis kinetics using a comprehensive set of reactions. We then show that all features of interest are accurately reproduced with 15 reactions. An analytical solution for steady-state concentrations of the 15 reactions reveals regions in [H2] and [O2] where the H2O2 concentration is not unique both stable and unstable concentrations exist. The boundary of this region can be characterized analytically as a function of G-values and rate constants independent of dose rate. Physically, the boundary can be understood as separating a region where a steady-state H2O2 concentration exists, from one where it does not exist without a direct decomposition reaction. We show that this behavior is consistent with reported alpha radiolysis data and that no such behavior should occur for gamma radiolysis. We suggest experiments that could verify or discredit a critical concentration behavior for alpha radiolysis and could place more restrictive ranges on G-values from derived relationships between them.

  2. When and how does a prominence-like jet gain kinetic energy?

    SciTech Connect (OSTI)

    Liu, Jiajia; Liu, Rui; Zhang, Quanhao; Liu, Kai; Shen, Chenglong; Wang, S.; Wang, Yuming

    2014-02-20

    A jet is a considerable amount of plasma being ejected from the chromosphere or lower corona into the higher corona and is a common phenomenon. Usually, a jet is triggered by a brightening or a flare, which provides the first driving force to push plasma upward. In this process, magnetic reconnection is thought to be the mechanism to convert magnetic energy into thermal, nonthermal, and kinetic energies. However, most jets could reach an unusual high altitude and end much later than the end of its associated flare. This fact implies that there is another way to continuously transfer magnetic energy into kinetic energy even after the reconnection. The picture described above is well known in the community, but how and how much magnetic energy is released through a way other than reconnection is still unclear. By studying a prominence-like jet observed by SDO/AIA and STEREO-A/EUVI, we find that the continuous relaxation of the post-reconnection magnetic field structure is an important process for a jet to climb up higher than it could through only reconnection. The kinetic energy of the jet gained through the relaxation is 1.6 times that gained from the reconnection. The resultant energy flux is hundreds of times larger than the flux required for the local coronal heating, suggesting that such jets are a possible source to keep the corona hot. Furthermore, rotational motions appear all the time during the jet. Our analysis suggests that torsional Alfvn waves induced during reconnection could not be the only mechanism to release magnetic energy and drive jets.

  3. Analyzing and modeling the kinetics of amyloid beta pores associated with Alzheimer’s disease pathology

    SciTech Connect (OSTI)

    Ullah, Ghanim; Demuro, Angelo; Parker, Ian; Pearson, John E.; Xu, Shang -Zhong

    2015-09-08

    Amyloid beta (Aβ) oligomers associated with Alzheimer’s disease (AD) form Ca2+-permeable plasma membrane pores, leading to a disruption of the otherwise well-controlled intracellular calcium (Ca2+) homeostasis. The resultant up-regulation of intracellular Ca2+ concentration has detrimental implications for memory formation and cell survival. The gating kinetics and Ca2+ permeability of Aβ pores are not well understood. We have used computational modeling in conjunction with the ability of optical patch-clamping for massively parallel imaging of Ca2+ flux through thousands of pores in the cell membrane of Xenopus oocytes to elucidate the kinetic properties of Aβ pores. The fluorescence time-series data from individual pores were idealized and used to develop data-driven Markov chain models for the kinetics of the Aβ pore at different stages of its evolution. Our study provides the first demonstration of developing Markov chain models for ion channel gating that are driven by optical-patch clamp data with the advantage of experiments being performed under close to physiological conditions. As a result, we demonstrate the up-regulation of gating of various Ca2+ release channels due to Aβ pores and show that the extent and spatial range of such up-regulation increases as Aβ pores with low open probability and Ca2+ permeability transition into those with high open probability and Ca2+ permeability.

  4. Kinetic studies of dry sorent for medium temperature applications. Final report

    SciTech Connect (OSTI)

    Keener, T.C.; Wang, Z.

    1996-07-12

    The purpose of this project is to investigate the fundamental nature of sorbent reactivity and reaction kinetics in the medium temperature range from 600{degrees}F (316{degrees}C) to 1200{degrees}F (649{degrees}C) available in the convective pass of a boiler upstream of the economizer, where dry sorbents are injected to remove SO{sub 2} from the flue gas. Research focuses on the mechanisms of sorbent- flue gas interaction under economizer and hot baghouse conditions utilizing the experimental setup and the results of the first four years of research.

  5. Final Report: Mechanisms of sputter ripple formation: coupling among energetic ions, surface kinetics, stress and composition

    SciTech Connect (OSTI)

    Chason, Eric; Shenoy, Vivek

    2013-01-22

    Self-organized pattern formation enables the creation of nanoscale surface structures over large areas based on fundamental physical processes rather than an applied template. Low energy ion bombardment is one such method that induces the spontaneous formation of a wide variety of interesting morphological features (e.g., sputter ripples and/or quantum dots). This program focused on the processes controlling sputter ripple formation and the kinetics controlling the evolution of surfaces and nanostructures in high flux environments. This was done by using systematic, quantitative experiments to measure ripple formation under a variety of processing conditions coupled with modeling to interpret the results.

  6. Evaporative cooling of microscopic water droplets in vacuo: Molecular dynamics simulations and kinetic gas theory

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Schlesinger, Daniel; Sellberg, Jonas A.; Nilsson, Anders; Pettersson, Lars G. M.

    2016-03-22

    In the present study, we investigate the process of evaporative cooling of nanometer-sized droplets in vacuum using molecular dynamics simulations with the TIP4P/2005 water model. The results are compared to the temperature evolution calculated from the Knudsen theory of evaporation which is derived from kinetic gas theory. The calculated and simulation results are found to be in very good agreement for an evaporation coefficient equal to unity. Lastly, our results are of interest to experiments utilizing droplet dispensers as well as to cloud micro-physics.

  7. Wetting kinetics of water nano-droplet containing non-surfactant nanoparticles: A molecular dynamics study

    SciTech Connect (OSTI)

    Lu, Gui; Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, Pennsylvania 19104 ; Hu, Han; Sun, Ying E-mail: ysun@coe.drexel.edu; Duan, Yuanyuan E-mail: ysun@coe.drexel.edu

    2013-12-16

    In this Letter, dynamic wetting of water nano-droplets containing non-surfactant gold nanoparticles on a gold substrate is examined via molecular dynamics simulations. The results show that the addition of non-surfactant nanoparticles hinders the nano-second droplet wetting process, attributed to the increases in both surface tension of the nanofluid and friction between nanofluid and substrate. The droplet wetting kinetics decreases with increasing nanoparticle loading and water-particle interaction energy. The observed wetting suppression and the absence of nanoparticle ordering near the contact line of nano-sized droplets differ from the wetting behaviors reported from nanofluid droplets of micron size or larger.

  8. Studying The Kinetics Of Crystalline Silicon Nanoparticle Lithiation With In-Situ Transmission Electron Microscopy

    SciTech Connect (OSTI)

    Mcdowell, Matthew T.; Ryu, Ill; Lee, Seokwoo; Wang, Chong M.; Nix, William D.; Cui, Yi

    2012-11-27

    Silicon is an attractive high-capacity anode material for Li-ion batteries, but a comprehensive understanding of the massive ~300% volume change and fracture during lithiation/delithiation is necessary to reliably employ Si anodes. Here, in-situ transmission electron microscopy (TEM) of the lithiation of crystalline Si nanoparticles reveals that the reaction slows down as it progresses into the particle interior. Analysis suggests that this behavior is due to the influence of mechanical stress at the reaction front on the driving force for the reaction. These experiments give insight into the factors controlling the kinetics of this unique reaction.

  9. Nitrogen effects on crystallization kinetics of amorphous TiOxNy thin films

    SciTech Connect (OSTI)

    Hukari, Kyle; Dannenberg, Rand; Stach, E.A.

    2001-03-30

    The crystallization behavior of amorphous TiOxNy (x>>y) thin films was investigated by in-situ transmission electron microscopy. The Johnson-Mehl-Avrami-Kozolog (JMAK) theory is used to determine the Avrami exponent, activation energy, and the phase velocity pre-exponent. Addition of nitrogen inhibits diffusion, increasing the nucleation temperature, while decreasing the growth activation energy. Kinetic variables extracted from individual crystallites are compared to JMAK analysis of the fraction transformed and a change of 6 percent in the activation energy gives agreement between the methods. From diffraction patterns and index of refraction the crystallized phase was found to be predominantly anatase.

  10. Electron kinetic effects on interferometry and polarimetry in high temperature fusion plasmas

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    vvmirnov IP Address: 128.104.165.118 This content was downloaded on 09/07/2014 at 19:52 Please note that terms and conditions apply. Electron kinetic effects on interferometry and polarimetry in high temperature fusion plasmas View the table of contents for this issue, or go to the journal homepage for more 2013 Nucl. Fusion 53 113005 (http://iopscience.iop.org/0029-5515/53/11/113005) Home Search Collections Journals About Contact us My IOPscience IOP PUBLISHING and INTERNATIONAL ATOMIC ENERGY

  11. UCRL-JC-l20677 PREPRINT Detailed and Global Chemical Kinetics Model for Hydrogen

    Office of Scientific and Technical Information (OSTI)

    UCRL-JC-l20677 PREPRINT Detailed and Global Chemical Kinetics Model for Hydrogen N. M. Marinov C IC Westbrook W . J. P i k This paper was prepared for submittal to the 8th International Symposium on Transport Properties October 1995 San Fr?ncisco, CA March 1995 DISCLAIMER This document m p r e p a r e d a s a n account of work sponsored by an agencyof the United States Government. Neither the United States Government nor the University o f CaMomia nor any o f t h e i r employees, makes any

  12. Influence of carbon partitioning kinetics on final Austenite fraction during quenching and partitioning

    SciTech Connect (OSTI)

    Clarke, Amy J; Speer, John G; Matlock, David K; Rizzo, F C; Edmonds, David V; Santofimia, Maria J

    2009-01-01

    The quenching and partitioning (Q&P) process is a two-stage heat-treatment procedure proposed for producing steel microstructures that contain carbon-enriched retained austenite. In Q&P processing, austenite stabilization is accomplished by carbon partitioning from supersaturated martensite. A quench temperature selection methodology was developed to predict an optimum process quench temperature; extension of this methodology to include carbon partitioning kinetics is developed here. Final austenite fraction is less sensitive to quench temperature than previously predicted, in agreement with experimental results.

  13. THE IMPACT OF KINETICS ON NEPHELINE FORMATION IN NUCLEAR WASTE GLASSES

    SciTech Connect (OSTI)

    Amoroso, J.

    2011-03-07

    Sixteen glass compositions were selected to study the potential impacts of the kinetics of nepheline formation in high-level nuclear waste (HLW) glass. The chosen compositions encompassed a relatively large nepheline discriminator (ND) range, 0.40-0.66, and included a relatively broad range, and amount of, constituents including high aluminum and high boron concentrations. All glasses were fabricated in the laboratory and subsequently exposed to six different cooling treatments. The cooling treatments consisted of three 'stepped' profiles and their corresponding 'smooth' profiles. Included in the cooling treatment was the Defense Waste Processing Facility (DWPF) canister centerline cooling (CCC) profile in addition to a 'faster' and a 'slower' total cooling line. After quenching and heat treating, x-ray diffraction confirmed the type and amount of any resultant crystallization. The target compositions were shown to be consistent with the measured compositions. Two quenched glasses and several treated glasses exhibited minor amounts of spinel and spinel-like phases. Nepheline was not observed in any of the quenched glasses but was observed in many of the treated glasses. The amount of nepheline ranged from approximately 2wt% to 30wt% for samples cooled over shorter times and longer times respectively. Differences were observed in the amount of nepheline crystallization after smooth and stepped cooling and increased with total cooling time. In some glasses, nepheline crystallization appeared to be directly proportional to total cooling time while the total amount of nepheline crystallization varied, suggesting that the nepheline crystallization rate was independent of (or at least faster than) cooling rate but, varied depending on the glass composition. On the contrary, in another glass, nepheline crystallization appeared to be inversely proportional to cooling rate. The high alumina glasses, predicted to form nepheline according to the ND, did not precipitate nepheline. Additionally, analysis from different regions of treated glasses indicated that nepheline nucleation and growth occurs at the glass/crucible and glass/atmosphere interfaces. Furthermore, the measured amount of non-nepheline phases appeared independent of the sampling region. It is postulated that crucible-scale methods used to heat treat HLW glass, such as the CCC method, artificially induce nepheline formation in the glass. The results of this study suggest nepheline kinetics can vary significantly depending on glass composition and, more importantly, glasses fabricated using current DWPF conditions are potentially susceptible to the impact of nepheline kinetics. This report summarizes the supporting research and provides the basis for continued research on nepheline kinetics and its effects on HLW glasses.

  14. Kinetics of visible light photo-oxidation of Ge nanocrystals:Theory and in situ measurement

    SciTech Connect (OSTI)

    Sharp, I.D.; Xu, Q.; Yuan, C.W.; Beeman, J.W.; Ager III, J.W.; Chrzan, D.C.; Haller, E.E.

    2006-11-14

    Photo-oxidation of Ge nanocrystals illuminated with visible laser light under ambient conditions was investigated. The photo-oxidation kinetics were monitored by in situ measurement of the crystalline Ge volume fraction by Raman spectroscopy. The effects of laser power and energy on the extent of oxidation were measured using both in situ and ex situ Raman scattering techniques. A mechanistic model in which the tunneling of photo-excited carriers to the oxide surface for electron activated molecular oxygen dissociation is proposed. This quantitative model successfully describes all experimental photo-oxidation observations using physical parameters.

  15. Bifunctional anion-exchange resins with improved selectivity and exchange kinetics

    DOE Patents [OSTI]

    Alexandratos, Spiro D. (Knoxville, TN); Brown, Gilbert M. (Knoxville, TN); Bonnesen, Peter V. (Knoxville, TN); Moyer, Bruce A. (Oak Ridge, TN)

    2000-01-01

    Disclosed herein are a class of anion exchange resins containing two different exchange sites with improved selectivity and sorptive capability for chemical species in solution, such as heptavalent technetium (as pertechnetate anion, TcO.sub.4.sup.-). The resins are prepared by first reacting haloalkylated crosslinked copolymer beads with a large tertiary amine in a solvent in which the resin beads can swell, followed by reaction with a second, smaller, tertiary amine to more fully complete the functionalization of the resin. The resins have enhanced selectivity, capacity, and exchange kinetics.

  16. Guest Molecule Exchange Kinetics for the 2012 Ignik Sikumi Gas Hydrate Field Trial

    SciTech Connect (OSTI)

    White, Mark D.; Lee, Won Suk

    2014-05-14

    A commercially viable technology for producing methane from natural gas hydrate reservoirs remains elusive. Short-term depressurization field tests have demonstrated the potential for producing natural gas via dissociation of the clathrate structure, but the long-term performance of the depressurization technology ultimately requires a heat source to sustain the dissociation. A decade of laboratory experiments and theoretical studies have demonstrated the exchange of pure CO2 and N2-CO2 mixtures with CH4 in sI gas hydrates, yielding critical information about molecular mechanisms, recoveries, and exchange kinetics. Findings indicated the potential for producing natural gas with little to no production of water and rapid exchange kinetics, generating sufficient interest in the guest-molecule exchange technology for a field test. In 2012 the U.S. DOE/NETL, ConocoPhillips Company, and Japan Oil, Gas and Metals National Corporation jointly sponsored the first field trial of injecting a mixture of N2-CO2 into a CH4-hydrate bearing formation beneath the permafrost on the Alaska North Slope. Known as the Ignik Sikumi #1 Gas Hydrate Field Trial, this experiment involved three stages: 1) the injection of a N2-CO2 mixture into a targeted hydrate-bearing layer, 2) a 4-day pressurized soaking period, and 3) a sustained depressurization and fluid production period. Data collected during the three stages of the field trial were made available after an extensive quality check. These data included continuous temperature and pressure logs, injected and recovered fluid compositions and volumes. The Ignik Sikumi #1 data set is extensive, but contains no direct evidence of the guest-molecule exchange process. This investigation is directed at using numerical simulation to provide an interpretation of the collected data. A numerical simulator, STOMP-HYDT-KE, was recently completed that solves conservation equations for energy, water, mobile fluid guest molecules, and hydrate guest molecules, for up to three gas hydrate guest molecules: CH4, CO2, and N2. The independent tracking of mobile fluid and hydrate guest molecules allows for the kinetic exchange of guest molecules between the mobile fluids and hydrate. The particular interest of this numerical investigation is to determine whether kinetic exchange parameters, determined from laboratory-scale experiments, are directly applicable to interpreting the Ignik Sikumi #1 data.

  17. Simulation of atomic diffusion in the Fcc NiAl system: A kinetic Monte Carlo study

    SciTech Connect (OSTI)

    Alfonso, Dominic R.; Tafen, De Nyago

    2015-04-28

    The atomic diffusion in fcc NiAl binary alloys was studied by kinetic Monte Carlo simulation. The environment dependent hopping barriers were computed using a pair interaction model whose parameters were fitted to relevant data derived from electronic structure calculations. Long time diffusivities were calculated and the effect of composition change on the tracer diffusion coefficients was analyzed. These results indicate that this variation has noticeable impact on the atomic diffusivities. A reduction in the mobility of both Ni and Al is demonstrated with increasing Al content. As a result, examination of the pair interaction between atoms was carried out for the purpose of understanding the predicted trends.

  18. Sintering Kinetics of Inkjet Printed Conductive Silver Lines on Insulating Plastic Substrate

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhou, Wenchao; List, III, Frederick Alyious; Duty, Chad E; Babu, Sudarsanam Suresh

    2015-01-24

    This paper focuses on sintering kinetics of inkjet printed lines containing silver nanoparticles deposited on a plastic substrate. Upon heat treatment, the change of resistance in the printed lines was measured as a function of time and sintering temperatures from 150 to 200 C. A critical temperature was observed for the sintering process, beyond which there was no further reduction in resistance. Analysis shows the critical temperature correlates to the boiling point of the solvent, which is attributed to a liquid-mediated sintering mechanism. It is demonstrated that the sintering process shuts down after the solvent has completely evaporated.

  19. Isobutane ignition delay time measurements at high pressure and detailed chemical kinetic simulations

    SciTech Connect (OSTI)

    Healy, D.; Curran, H.J.; Donato, N.S.; Aul, C.J.; Petersen, E.L.; Zinner, C.M.; Bourque, G.

    2010-08-15

    Rapid compression machine and shock-tube ignition experiments were performed for real fuel/air isobutane mixtures at equivalence ratios of 0.3, 0.5, 1, and 2. The wide range of experimental conditions included temperatures from 590 to 1567 K at pressures of approximately 1, 10, 20, and 30 atm. These data represent the most comprehensive set of experiments currently available for isobutane oxidation and further accentuate the complementary attributes of the two techniques toward high-pressure oxidation experiments over a wide range of temperatures. The experimental results were used to validate a detailed chemical kinetic model composed of 1328 reactions involving 230 species. This mechanism has been successfully used to simulate previously published ignition delay times as well. A thorough sensitivity analysis was performed to gain further insight to the chemical processes occurring at various conditions. Additionally, useful ignition delay time correlations were developed for temperatures greater than 1025 K. Comparisons are also made with available isobutane data from the literature, as well as with 100% n-butane and 50-50% n-butane-isobutane mixtures in air that were presented by the authors in recent studies. In general, the kinetic model shows excellent agreement with the data over the wide range of conditions of the present study. (author)

  20. n-Butane: Ignition delay measurements at high pressure and detailed chemical kinetic simulations

    SciTech Connect (OSTI)

    Healy, D.; Curran, H.J.; Donato, N.S.; Aul, C.J.; Petersen, E.L.; Zinner, C.M.; Bourque, G.

    2010-08-15

    Ignition delay time measurements were recorded at equivalence ratios of 0.3, 0.5, 1, and 2 for n-butane at pressures of approximately 1, 10, 20, 30 and 45 atm at temperatures from 690 to 1430 K in both a rapid compression machine and in a shock tube. A detailed chemical kinetic model consisting of 1328 reactions involving 230 species was constructed and used to validate the delay times. Moreover, this mechanism has been used to simulate previously published ignition delay times at atmospheric and higher pressure. Arrhenius-type ignition delay correlations were developed for temperatures greater than 1025 K which relate ignition delay time to temperature and concentration of the mixture. Furthermore, a detailed sensitivity analysis and a reaction pathway analysis were performed to give further insight to the chemistry at various conditions. When compared to existing data from the literature, the model performs quite well, and in several instances the conditions of earlier experiments were duplicated in the laboratory with overall good agreement. To the authors' knowledge, the present paper presents the most comprehensive set of ignition delay time experiments and kinetic model validation for n-butane oxidation in air. (author)

  1. Isothermal Solid-State Transformation Kinetics Applied to Pd/Cu Alloy Membrane Fabrication

    SciTech Connect (OSTI)

    Pomerantz, Natalie L; Payzant, E Andrew; Ma, Yi Hua

    2010-01-01

    In this work, time-resolved, in situ high-temperature X-ray diffraction (HT-XRD) was used to study the solid-state transformation kinetics of the formation of the fcc Pd/Cu alloy from Pd/Cu bi-layers for the purpose of fabricating sulfur tolerant Pd/Cu membranes for H2 separation. Thin layers of Pd and Cu (total ~15 wt% Cu) were deposited on porous stainless steel (PSS) with the electroless deposition method and annealed in H2 at 500, 550 and 600 C. The kinetics of the annealing process were successfully described by the Avrami nucleation and growth model showing that the annealing process was diffusion controlled and one dimensional. The activation energy for the solid-state transformation was 175 kJ/mol, which was similar to the activation energy of Pd-Cu bulk interdiffusion. Furthermore, the Avrami model was able to successfully describe the changes in permeance and activation energy observed in Pd/Cu alloy membranes during characterization as they were annealed at high temperatures.

  2. KINETIC MODELING OF PARTICLE ACCELERATION IN A SOLAR NULL-POINT RECONNECTION REGION

    SciTech Connect (OSTI)

    Baumann, G.; Haugbolle, T.; Nordlund, A.

    2013-07-10

    The primary focus of this paper is on the particle acceleration mechanism in solar coronal three-dimensional reconnection null-point regions. Starting from a potential field extrapolation of a Solar and Heliospheric Observatory (SOHO) magnetogram taken on 2002 November 16, we first performed magnetohydrodynamics (MHD) simulations with horizontal motions observed by SOHO applied to the photospheric boundary of the computational box. After a build-up of electric current in the fan plane of the null point, a sub-section of the evolved MHD data was used as initial and boundary conditions for a kinetic particle-in-cell model of the plasma. We find that sub-relativistic electron acceleration is mainly driven by a systematic electric field in the current sheet. A non-thermal population of electrons with a power-law distribution in energy forms in the simulated pre-flare phase, featuring a power-law index of about -1.78. This work provides a first step toward bridging the gap between macroscopic scales on the order of hundreds of Mm and kinetic scales on the order of centimeter in the solar corona, and explains how to achieve such a cross-scale coupling by utilizing either physical modifications or (equivalent) modifications of the constants of nature. With their exceptionally high resolution-up to 135 billion particles and 3.5 billion grid cells of size 17.5 km-these simulations offer a new opportunity to study particle acceleration in solar-like settings.

  3. Reactions of plutonium and uranium with water: Kinetics and potential hazards

    SciTech Connect (OSTI)

    Haschke, J.M.

    1995-12-01

    The chemistry and kinetics of reactions between water and the metals and hydrides of plutonium and uranium are described in an effort to consolidate information for assessing potential hazards associated with handling and storage. New experimental results and data from literature sources are presented. Kinetic dependencies on pH, salt concentration, temperature and other parameters are reviewed. Corrosion reactions of the metals in near-neutral solutions produce a fine hydridic powder plus hydrogen. The corrosion rate for plutonium in sea water is a thousand-fold faster than for the metal in distilled water and more than a thousand-fold faster than for uranium in sea water. Reaction rates for immersed hydrides of plutonium and uranium are comparable and slower than the corrosion rates for the respective metals. However, uranium trihydride is reported to react violently if a quantity greater than twenty-five grams is rapidly immersed in water. The possibility of a similar autothermic reaction for large quantities of plutonium hydride cannot be excluded. In addition to producing hydrogen, corrosion reactions convert the massive metals into material forms that are readily suspended in water and that are aerosolizable and potentially pyrophoric when dry. Potential hazards associated with criticality, environmental dispersal, spontaneous ignition and explosive gas mixtures are outlined.

  4. Neutron scattering from myelin revisited: bilayer asymmetry and water-exchange kinetics

    SciTech Connect (OSTI)

    Denninger, Andrew R. [Boston College, Chestnut Hill, MA 02467 (United States); Dem, Bruno; Cristiglio, Viviana [Institut LaueLangevin (ILL), CS 20156, F-38042 Grenoble CEDEX 9 (France); LeDuc, Graldine [European Synchrotron Radiation Facility (ESRF), CS 40220, F-38043 Grenoble CEDEX 9 (France); Feller, W. Bruce [NOVA Scientific Inc., Sturbridge, MA 01566 (United States); Kirschner, Daniel A., E-mail: kirschnd@bc.edu [Boston College, Chestnut Hill, MA 02467 (United States)

    2014-12-01

    The structure of internodal myelin in the rodent central and peripheral nervous systems has been determined using neutron diffraction. The kinetics of water exchange in these tissues is also described. Rapid nerve conduction in the central and peripheral nervous systems (CNS and PNS, respectively) of higher vertebrates is brought about by the ensheathment of axons with myelin, a lipid-rich, multilamellar assembly of membranes. The ability of myelin to electrically insulate depends on the regular stacking of these plasma membranes and on the presence of a number of specialized membrane-protein assemblies in the sheath, including the radial component, SchmidtLanterman incisures and the axoglial junctions of the paranodal loops. The disruption of this fine-structure is the basis for many demyelinating neuropathies in the CNS and PNS. Understanding the processes that govern myelin biogenesis, maintenance and destabilization requires knowledge of myelin structure; however, the tight packing of internodal myelin and the complexity of its junctional specializations make myelin a challenging target for comprehensive structural analysis. This paper describes an examination of myelin from the CNS and PNS using neutron diffraction. This investigation revealed the dimensions of the bilayers and aqueous spaces of myelin, asymmetry between the cytoplasmic and extracellular leaflets of the membrane, and the distribution of water and exchangeable hydrogen in internodal multilamellar myelin. It also uncovered differences between CNS and PNS myelin in their water-exchange kinetics.

  5. Chemical Kinetic Simulation of the Combustion of Bio-based Fuels

    SciTech Connect (OSTI)

    Ashen, Ms. Refuyat; Cushman, Ms. Katherine C.

    2007-10-01

    Due to environmental and economic issues, there has been an increased interest in the use of alternative fuels. However, before widespread use of biofuels is feasible, the compatibility of these fuels with specific engines needs to be examined. More accurate models of the chemical combustion of alternative fuels in Homogeneous Charge Compression Ignition (HCCI) engines are necessary, and this project evaluates the performance of emissions models and uses the information gathered to study the chemical kinetics involved. The computer simulations for each alternative fuel were executed using the Chemkin chemical kinetics program, and results from the runs were compared with data gathered from an actual engine that was run under similar conditions. A new heat transfer mechanism was added to the existing model's subroutine, and simulations were then conducted using the heat transfer mechanism. Results from the simulation proved to be accurate when compared with the data taken from the actual engine. The addition of heat transfer produced more realistic temperature and pressure data for biodiesel when biodiesel's combustion was simulated in an HCCI engine. The addition of the heat transfer mechanism essentially lowered the peak pressures and peak temperatures during combustion of all fuels simulated in this project.

  6. Chemical kinetic modeling of high pressure propane oxidation and comparison to experimental results. Revision 1

    SciTech Connect (OSTI)

    Koert, D.N.; Pitz, W.J.; Bozzelli, J.W.; Cernansky, N.P.

    1996-02-01

    A pressure dependent kinetic mechanism for propane oxidation is developed and compared to experimental data from a high pressure flow reactor. Experimental conditions range from 10--15 atm, 650--800 K, and a residence time of 198 ms for propane-air mixtures at an equivalence ratio of 0.4. The experimental results clearly indicate a negative temperature coefficient (NTC) behavior. The chemistry describing this phenomena is critical in understanding automotive engine knock and cool flame oscillations. Results of the numerical model are compared to a spectrum of stable species profiles sampled from the flow reactor. Rate constants and product channels for the reaction of propyl radicals, hydroperoxy-propyl radicals and important isomers (radicals) with O{sub 2} were estimated using thermodynamic properties, with multifrequency quantum Kassel Theory for k(E) coupled with modified strong collision analysis for fall-off. Results of the chemical kinetic model show an NTC region over nearly the same temperature regime as observed in the experiments. Sensitivity analysis identified the key reaction steps that control the rate of oxidation in the NTC region. The model reasonably simulates the profiles for many of the major and minor species observed in the experiments.

  7. Extension of the quantum-kinetic model to lunar and Mars return physics

    SciTech Connect (OSTI)

    Liechty, D. S.; Lewis, M. J.

    2014-02-15

    The ability to compute rarefied, ionized hypersonic flows is becoming more important as missions such as Earth reentry, landing high-mass payloads on Mars, and the exploration of the outer planets and their satellites are being considered. A recently introduced molecular-level chemistry model, the quantum-kinetic, or Q-K, model that predicts reaction rates for gases in thermal equilibrium and non-equilibrium using only kinetic theory and fundamental molecular properties, is extended in the current work to include electronic energy level transitions and reactions involving charged particles. Like the Q-K procedures for neutral species chemical reactions, these new models are phenomenological procedures that aim to reproduce the reaction/transition rates but do not necessarily capture the exact physics. These engineering models are necessarily efficient due to the requirement to compute billions of simulated collisions in direct simulation Monte Carlo (DSMC) simulations. The new models are shown to generally agree within the spread of reported transition and reaction rates from the literature for near equilibrium conditions.

  8. Validity of the Taylor hypothesis for linear kinetic waves in the weakly collisional solar wind

    SciTech Connect (OSTI)

    Howes, G. G.; Klein, K. G.; TenBarge, J. M.

    2014-07-10

    The interpretation of single-point spacecraft measurements of solar wind turbulence is complicated by the fact that the measurements are made in a frame of reference in relative motion with respect to the turbulent plasma. The Taylor hypothesisthat temporal fluctuations measured by a stationary probe in a rapidly flowing fluid are dominated by the advection of spatial structures in the fluid rest frameis often assumed to simplify the analysis. But measurements of turbulence in upcoming missions, such as Solar Probe Plus, threaten to violate the Taylor hypothesis, either due to slow flow of the plasma with respect to the spacecraft or to the dispersive nature of the plasma fluctuations at small scales. Assuming that the frequency of the turbulent fluctuations is characterized by the frequency of the linear waves supported by the plasma, we evaluate the validity of the Taylor hypothesis for the linear kinetic wave modes in the weakly collisional solar wind. The analysis predicts that a dissipation range of solar wind turbulence supported by whistler waves is likely to violate the Taylor hypothesis, while one supported by kinetic Alfvn waves is not.

  9. Surface oxidation energetics and kinetics on MoS{sub 2} monolayer

    SciTech Connect (OSTI)

    KC, Santosh; Longo, Roberto C.; Wallace, Robert M.; Cho, Kyeongjae

    2015-04-07

    In this work, surface oxidation of monolayer MoS{sub 2} (one of the representative semiconductors in transition-metal dichalcogenides) has been investigated using density functional theory method. Oxygen interaction with MoS{sub 2} shows that, thermodynamically, the surface tends to be oxidized. However, the dissociative absorption of molecular oxygen on the MoS{sub 2} surface is kinetically limited due to the large energy barrier at low temperature. This finding elucidates the air stability of MoS{sub 2} surface in the atmosphere. Furthermore, the presence of defects significantly alters the surface stability and adsorption mechanisms. The electronic properties of the oxidized surface have been examined as a function of oxygen adsorption and coverage as well as substitutional impurities. Our results on energetics and kinetics of oxygen interaction with the MoS{sub 2} monolayer are useful for the understanding of surface oxidation, air stability, and electronic properties of transition-metal dichalcogenides at the atomic scale.

  10. Anaerobic waste-activated sludge digestion - A bioconversion mechanism and kinetic model

    SciTech Connect (OSTI)

    Shimizu, Tatsuo; Kudo, Kenzo; Nasu, Yoshikazu )

    1993-05-01

    The anaerobic bioconversion of raw and mechanically lysed waste-activated sludge was kinetically investigated. The hydrolysis of the biopolymers, such as protein, which leaked out from the biological sludge with ultrasonic lysis, was a first-order reaction in anaerobic digestion and the rate constant was much higher than the decay rate constant of the raw waste activated sludge. An anaerobic digestion model that is capable of evaluating the effect of the mechanical sludge lysis on digestive performance was developed. The present model includes four major biological processes - the release of intracellular matter with sludge lysis; hydrolysis of biopolymers to volatile acids; the degradation of various volatile acids to acetate; and the conversion of acetate and hydrogen to methane. Each process was assumed to follow first-order kinetics. The model approximately simulated the overall process performance of the anaerobic digestion of waste-activated sludge. The model suggested that when the lysed waste-activated sludge was fed, the overall digestive performance remarkably increased in the two-phase system consisting of an acid forming process and a methanogenic process, which ensured the symbiotic growth of acetogenic and methanogenic bacteria.

  11. Kinetics of silicide formation over a wide range of heating rates spanning six orders of magnitude

    SciTech Connect (OSTI)

    Molina-Ruiz, Manel; Lopeanda, Aitor F.; Gonzalez-Silveira, Marta; Garcia, Gemma; Clavaguera-Mora, Maria T. [Grup de Nanomaterials i Microsistemes, Departament de Fsica, Universitat Autnoma de Barcelona, 08193 Bellaterra (Spain); Peral, Inma [ALBA Synchrotron Light Facility, 08290 Cerdanyola del Valls (Spain); Rodrguez-Viejo, Javier, E-mail: javier.rodriguez@uab.cat [Grup de Nanomaterials i Microsistemes, Departament de Fsica, Universitat Autnoma de Barcelona, 08193 Bellaterra (Spain); MATGAS Research Centre, UAB Campus, 08193 Bellaterra (Spain)

    2014-07-07

    Kinetic processes involving intermediate phase formation are often assumed to follow an Arrhenius temperature dependence. This behavior is usually inferred from limited data over narrow temperature intervals, where the exponential dependence is generally fully satisfied. However, direct evidence over wide temperature intervals is experimentally challenging and data are scarce. Here, we report a study of silicide formation between a 12?nm film of palladium and 15?nm of amorphous silicon in a wide range of heating rates, spanning six orders of magnitude, from 0.1 to 10{sup 5?}K/s, or equivalently more than 300?K of variation in reaction temperature. The calorimetric traces exhibit several distinct exothermic events related to interdiffusion, nucleation of Pd{sub 2}Si, crystallization of amorphous silicon, and vertical growth of Pd{sub 2}Si. Interestingly, the thickness of the initial nucleation layer depends on the heating rate revealing enhanced mass diffusion at the fastest heating rates during the initial stages of the reaction. In spite of this, the formation of the silicide strictly follows an Arrhenius temperature dependence over the whole temperature interval explored. A kinetic model is used to fit the calorimetric data over the complete heating rate range. Calorimetry is complemented by structural analysis through transmission electron microscopy and both standard and in-situ synchrotron X-ray diffraction.

  12. Mathematical treatment of isotopologue and isotopomer speciation and fractionation in biochemical kinetics

    SciTech Connect (OSTI)

    Maggi, F.M.; Riley, W.J.

    2009-11-01

    We present a mathematical treatment of the kinetic equations that describe isotopologue and isotopomer speciation and fractionation during enzyme-catalyzed biochemical reactions. These equations, presented here with the name GEBIK (general equations for biochemical isotope kinetics) and GEBIF (general equations for biochemical isotope fractionation), take into account microbial biomass and enzyme dynamics, reaction stoichiometry, isotope substitution number, and isotope location within each isotopologue and isotopomer. In addition to solving the complete GEBIK and GEBIF, we also present and discuss two approximations to the full solutions under the assumption of biomass-free and enzyme steady-state, and under the quasi-steady-state assumption as applied to the complexation rate. The complete and approximate approaches are applied to observations of biological denitrification in soils. Our analysis highlights that the full GEBIK and GEBIF provide a more accurate description of concentrations and isotopic compositions of substrates and products throughout the reaction than do the approximate forms. We demonstrate that the isotopic effects of a biochemical reaction depend, in the most general case, on substrate and complex concentrations and, therefore, the fractionation factor is a function of time. We also demonstrate that inverse isotopic effects can occur for values of the fractionation factor smaller than 1, and that reactions that do not discriminate isotopes do not necessarily imply a fractionation factor equal to 1.

  13. Alternative S2 Hinge Regions of the Myosin Rod Affect Myofibrillar Structure and Myosin Kinetics

    SciTech Connect (OSTI)

    Miller, Mark S.; Dambacher, Corey M.; Knowles, Aileen F.; Braddock, Joan M.; Farman, Gerrie P.; Irving, Thomas C.; Swank, Douglas M.; Bernstein, Sanford I.; Maughan, David W.

    2009-07-01

    The subfragment 2/light meromyosin 'hinge' region has been proposed to significantly contribute to muscle contraction force and/or speed. Transgenic replacement of the endogenous fast muscle isovariant hinge A (exon 15a) in Drosophila melanogaster indirect flight muscle with the slow muscle hinge B (exon 15b) allows examination of the structural and functional changes when only this region of the myosin molecule is different. Hinge B was previously shown to increase myosin rod length, increase A-band and sarcomere length, and decrease flight performance compared to hinge A. We applied additional measures to these transgenic lines to further evaluate the consequences of modifying this hinge region. Structurally, the longer A-band and sarcomere lengths found in the hinge B myofibrils appear to be due to the longitudinal addition of myosin heads. Functionally, hinge B, although a significant distance from the myosin catalytic domain, alters myosin kinetics in a manner consistent with this region increasing myosin rod length. These structural and functional changes combine to decrease whole fly wing-beat frequency and flight performance. Our results indicate that this hinge region plays an important role in determining myosin kinetics and in regulating thick and thin filament lengths as well as sarcomere length.

  14. On the applicability of the standard kinetic theory to the study of nanoplasmas

    SciTech Connect (OSTI)

    D'Angola, A.; Boella, E.

    2014-08-15

    Kinetic theory applies to systems with a large number of particles, while nanoplasma generated by the interaction of ultra–short laser pulses with atomic clusters are systems composed by a relatively small number (10{sup 2} ÷ 10{sup 4}) of electrons and ions. In the paper, the applicability of the kinetic theory for studying nanoplasmas is discussed. In particular, two typical phenomena are investigated: the collisionless expansion of electrons in a spherical nanoplasma with immobile ions and the formation of shock shells during Coulomb explosions. The analysis, which is carried out comparing ensemble averages obtained by solving the exact equations of motion with reference solutions of the Vlasov-Poisson model, shows that for the dynamics of the electrons the error of the usually employed models is of the order of few percents (but the standard deviation in a single experiment can be of the order of 10%). Instead, special care must be taken in the study of shock formation, as the discrete structure of the electric charge can destroy or strongly modify the phenomenon.

  15. KINETIC PLASMA TURBULENCE IN THE FAST SOLAR WIND MEASURED BY CLUSTER

    SciTech Connect (OSTI)

    Roberts, O. W.; Li, X.; Li, B.

    2013-05-20

    The k-filtering technique and wave polarization analysis are applied to Cluster magnetic field data to study plasma turbulence at the scale of the ion gyroradius in the fast solar wind. Waves are found propagating in directions nearly perpendicular to the background magnetic field at such scales. The frequencies of these waves in the solar wind frame are much smaller than the proton gyrofrequency. After the wavevector k is determined at each spacecraft frequency f{sub sc}, wave polarization property is analyzed in the plane perpendicular to k. Magnetic fluctuations have {delta}B > {delta}B{sub Parallel-To} (here the Parallel-To and refer to the background magnetic field B{sub 0}). The wave magnetic field has right-handed polarization at propagation angles {theta}{sub kB} < 90 Degree-Sign and >90 Degree-Sign . The magnetic field in the plane perpendicular to B{sub 0}, however, has no clear sense of a dominant polarization but local rotations. We discuss the merits and limitations of linear kinetic Alfven waves (KAWs) and coherent Alfven vortices in the interpretation of the data. We suggest that the fast solar wind turbulence may be populated with KAWs, small-scale current sheets, and Alfven vortices at ion kinetic scales.

  16. Kinetic simulations of the formation and stability of the field-reversed configuration

    SciTech Connect (OSTI)

    Omelchenko, Yu. A.

    2000-05-01

    The Field-Reversed Configuration (FRC) is a high-beta compact toroidal plasma confined primarily by poloidal fields. In the FRC the external field is reversed on axis by the diamagnetic current carried by thermal plasma particles. A three-dimensional, hybrid, particle-in-cell (zero-inertia fluid electrons, and kinetic ions), code FLAME, previously used to study ion rings [Yu. A. Omelchenko and R. N. Sudan, J. Comp. Phys. 133, 146 (1997)], is applied to investigate FRC formation and tilt instability. Axisymmetric FRC equilibria are obtained by simulating the standard experimental reversed theta-pinch technique. These are used to study the nonlinear tilt mode in the ''kinetic'' and ''fluid-like'' cases characterized by ''small'' ({approx}3) and ''large'' ({approx}12) ratios of the characteristic radial plasma size to the mean ion gyro-radius, respectively. The formation simulations have revealed the presence of a substantial toroidal (azimuthal) magnetic field inside the separatrix, generated due to the stretching of the poloidal field by a sheared toroidal electron flow. This is shown to be an important tilt-stabilizing effect in both cases. On the other hand, the tilt mode stabilization by finite Larmor radius effects has been found relatively insignificant for the chosen equilibria. (c) 2000 American Institute of Physics.

  17. Kinetic Effects on the Stability Properties of Field-reversed Configurations: II. Nonlinear Evolution

    SciTech Connect (OSTI)

    Elena V. Belova; Ronald C. Davidson; Hantao Ji; Masaaki Yamada

    2003-11-25

    Results of three-dimensional hybrid simulations of the field-reversed configuration (FRC) are presented. Emphasis of this work is on the nonlinear evolution of magnetohydrodynamic (MHD) instabilities in kinetic FRCs. A wide range of ''bar s'' values is considered, where the ''bar s'' is the FRC kinetic parameter, which measures the number of ion gyroradii in the configuration. The linear and nonlinear stability of MHD modes with toroidal mode numbers n greater than or equal to 1 is investigated, including the effects of ion rotation, finite electron pressure, and weak toroidal field. Low-''bar s'' simulations show nonlinear saturation of the n = 1 tilt mode. The n greater than or equal to 2 rotational modes are observed to grow during the nonlinear phase of the tilt instability due to ion spin-up in the toroidal direction. Large-''bar s'' simulations show no saturation of the tilt mode, and there is a slow nonlinear evolution of the instability after the initial fast linear growth. Overall, the hybrid simulations demonstrate the importance of nonlinear effects, which are responsible for the saturation of instabilities in low-''bar s'' configurations, and also for the increase in FRC life-time compared to MHD models in high-''bar s'' configurations.

  18. Hydrogen desorption kinetics for aqueous hydrogen fluoride and remote hydrogen plasma processed silicon (001) surfaces

    SciTech Connect (OSTI)

    King, Sean W. Davis, Robert F.; Carter, Richard J.; Schneider, Thomas P.; Nemanich, Robert J.

    2015-09-15

    The desorption kinetics of molecular hydrogen (H{sub 2}) from silicon (001) surfaces exposed to aqueous hydrogen fluoride and remote hydrogen plasmas were examined using temperature programmed desorption. Multiple H{sub 2} desorption states were observed and attributed to surface monohydride (SiH), di/trihydride (SiH{sub 2/3}), and hydroxide (SiOH) species, subsurface hydrogen trapped at defects, and hydrogen evolved during the desorption of surface oxides. The observed surface hydride species were dependent on the surface temperature during hydrogen plasma exposure with mono, di, and trihydride species being observed after low temperature exposure (150 °C), while predominantly monohydride species were observed after higher temperature exposure (450 °C). The ratio of surface versus subsurface H{sub 2} desorption was also found to be dependent on the substrate temperature with 150 °C remote hydrogen plasma exposure generally leading to more H{sub 2} evolved from subsurface states and 450 °C exposure leading to more H{sub 2} desorption from surface SiH{sub x} species. Additional surface desorption states were observed, which were attributed to H{sub 2} desorption from Si (111) facets formed as a result of surface etching by the remote hydrogen plasma or aqueous hydrogen fluoride treatment. The kinetics of surface H{sub 2} desorption were found to be in excellent agreement with prior investigations of silicon surfaces exposed to thermally generated atomic hydrogen.

  19. Kinetic and Thermodynamic Investigation of Hydrogen Release from Ethane 1,2-di-amineborane

    SciTech Connect (OSTI)

    Neiner, Doinita; Karkamkar, Abhijeet J.; Bowden, Mark; Choi, Young Joon; Luedtke, Avery T.; Holladay, Jamelyn D.; Fisher, Allison M.; Szymczak, Nathaniel; Autrey, Thomas

    2011-07-18

    The thermodynamics and kinetics of hydrogen (H2) release from ethane 1,2-di-amineborane (EDAB, BH3NH2CH2CH2NH2BH3) were measured using Calvet and differential scanning calorimetry (DSC), pressure-composition isotherms, and volumetric gas-burette experiments. The results presented here indicate that EDAB releases ~ 9 wt.% H2 at temperatures ranging from 100 C to 200 C in two moderately exothermic steps, approximately -101 kJ/mol H2 and -3.81 kJ/mol H2. Isothermal kinetic analysis shows that EDAB is more stable than ammonia borane (AB) at temperatures lower than 100C; however, the rates of hydrogen release are faster for EDAB than for AB at temperatures higher than 120C. In addition, no volatile impurities in the H2 released by EDAB were detected by mass spectrometry upon heating with 1C/min to 200C in a calorimeter.

  20. Chemical kinetic analysis of hydrogen-air ignition and reaction times

    SciTech Connect (OSTI)

    Rogers, R.C.; Schexnayder, C.J. Jr.

    1981-07-01

    An anaytical study of hydrogen air kinetics was performed. Calculations were made over a range of pressure from 0.2 to 4.0 atm, temperatures from 850 to 2000 K, and mixture equivalence ratios from 0.2 to 2.0. The finite rate chemistry model included 60 reactions in 20 species of the H2-O2-N2 system. The calculations also included an assessment of how small amounts of the chemicals H2O, NOx, H2O2, and O3 in the initial mixture affect ignition and reaction times, and how the variation of the third body efficiency of H2O relative of N2 in certain key reactions may affect reaction time. The results indicate that for mixture equivalence ratios between 0.5 and 1.7, ignition times are nearly constant however, the presence of H2O and NO can have significant effects on ignition times, depending on the mixture temperature. Reaction time is dominantly influenced by pressure but is nearly independent of initial temperature, equivalence ratio, and the addition of chemicals. Effects of kinetics on reaction at supersonic combustor conditions are discussed.

  1. Gas-kinetic unified algorithm for hypersonic flows covering various flow regimes solving Boltzmann model equation in nonequilibrium effect

    SciTech Connect (OSTI)

    Li, Zhihui; Ma, Qiang; Wu, Junlin; Jiang, Xinyu; Zhang, Hanxin

    2014-12-09

    Based on the Gas-Kinetic Unified Algorithm (GKUA) directly solving the Boltzmann model equation, the effect of rotational non-equilibrium is investigated recurring to the kinetic Rykov model with relaxation property of rotational degrees of freedom. The spin movement of diatomic molecule is described by moment of inertia, and the conservation of total angle momentum is taken as a new Boltzmann collision invariant. The molecular velocity distribution function is integrated by the weight factor on the internal energy, and the closed system of two kinetic controlling equations is obtained with inelastic and elastic collisions. The optimization selection technique of discrete velocity ordinate points and numerical quadrature rules for macroscopic flow variables with dynamic updating evolvement are developed to simulate hypersonic flows, and the gas-kinetic numerical scheme is constructed to capture the time evolution of the discretized velocity distribution functions. The gas-kinetic boundary conditions in thermodynamic non-equilibrium and numerical procedures are studied and implemented by directly acting on the velocity distribution function, and then the unified algorithm of Boltzmann model equation involving non-equilibrium effect is presented for the whole range of flow regimes. The hypersonic flows involving non-equilibrium effect are numerically simulated including the inner flows of shock wave structures in nitrogen with different Mach numbers of 1.5-Ma-25, the planar ramp flow with the whole range of Knudsen numbers of 0.0009-Kn-10 and the three-dimensional re-entering flows around tine double-cone body.

  2. Exploring the effect of fluid dynamics and kinetic mechanisms on n-heptane autoignition in transient jets

    SciTech Connect (OSTI)

    Viggiano, Annarita [Department of Environmental Engineering and Physics, University of Basilicata, viale dell'Ateneo Lucano 10, 85100 Potenza (Italy)

    2010-02-15

    The influence of physical parameters and of flow patterns on the prediction of n-heptane ignition dynamic in transient reacting n-heptane jets, in high pressure environment under laminar conditions, has been explored by using different kinetic mechanisms. Some preliminary transient laminar flamelet computations have been performed, thus showing that the sensitivity of the ignition time to strain rate depends on the kinetic mechanism used. Therefore, the structure of the reacting jet, in particular the localization of ignition spots, is investigated. The results show that, if the initial temperature of the reacting mixture is out of the intermediate range (800-1000 K) towards lower values, the fluid dynamics has an essential role. In this case, the ignition delay time is almost insensitive to the specific kinetic mechanism adopted, conversely it is severely shortened by increasing the streamwise velocity. The burning spot is located in the core of fuel roll-up, where low values of scalar dissipation rate occur. Nevertheless, the most reactive mixture fraction conditions are well predicted by chemical kinetics, as they are in good agreement with those computed for the one-dimensional diffusion layer. When the initial temperature of fuel and air is increased in the intermediate range, ignition is strongly dependent on the kinetic mechanism used. In these cases, the choice of an accurate chemical scheme is fundamental in order to obtain reliable results. (author)

  3. The response of the HMX-based material PBXN-9 to thermal insults: thermal decomposition kinetics and morphological changes

    SciTech Connect (OSTI)

    Glascoe, E A; Hsu, P C; Springer, H K; DeHaven, M R; Tan, N; Turner, H C

    2010-12-10

    PBXN-9, an HMX-formulation, is thermally damaged and thermally decomposed in order to determine the morphological changes and decomposition kinetics that occur in the material after mild to moderate heating. The material and its constituents were decomposed using standard thermal analysis techniques (DSC and TGA) and the decomposition kinetics are reported using different kinetic models. Pressed parts and prill were thermally damaged, i.e. heated to temperatures that resulted in material changes but did not result in significant decomposition or explosion, and analyzed. In general, the thermally damaged samples showed a significant increase in porosity and decrease in density and a small amount of weight loss. These PBXN-9 samples appear to sustain more thermal damage than similar HMX-Viton A formulations and the most likely reasons are the decomposition/evaporation of a volatile plasticizer and a polymorphic transition of the HMX from {beta} to {delta} phase.

  4. A Chemical Kinetic Modeling Study of the Effects of Oxygenated Hydrocarbons on Soot Emissions from Diesel Engines

    SciTech Connect (OSTI)

    Westbrook, C K; Pitz, W J; Curran, H J

    2005-11-14

    A detailed chemical kinetic modeling approach is used to examine the phenomenon of suppression of sooting in diesel engines by addition of oxygenated hydrocarbon species to the fuel. This suppression, which has been observed experimentally for a few years, is explained kinetically as a reduction in concentrations of soot precursors present in the hot products of a fuel-rich diesel ignition zone when oxygenates are included. Oxygenates decrease the overall equivalence ratio of the igniting mixture, producing higher ignition temperatures and more radical species to consume more soot precursor species, leading to lower soot production. The kinetic model is also used to show how different oxygenates, ester structures in particular, can have different soot-suppression efficiencies due to differences in molecular structure of the oxygenated species.

  5. Comparison of direct and quasi-static methods for neutron kinetic calculations with the EDF R and D COCAGNE code

    SciTech Connect (OSTI)

    Girardi, E.; Guerin, P.; Dulla, S.; Nervo, M.; Ravetto, P.

    2012-07-01

    Quasi-Static (QS) methods are quite popular in the reactor physics community and they exhibit two main advantages. First, these methods overcome both the limits of the Point Kinetic (PK) approach and the issues of the computational effort related to the direct discretization of the time-dependent neutron transport equation. Second, QS methods can be implemented in such a way that they can be easily coupled to very different external spatial solvers. In this paper, the results of the coupling between the QS methods developed by Politecnico di Torino and the EDF R and D core code COCAGNE are presented. The goal of these activities is to evaluate the performances of QS methods (in term of computational cost and precision) with respect to the direct kinetic solver (e.g. {theta}-scheme) already available in COCAGNE. Additionally, they allow to perform an extensive cross-validation of different kinetic models (QS and direct methods). (authors)

  6. A kinetic approach to modeling the manufacture of high density strucutral foam: Foaming and polymerization

    SciTech Connect (OSTI)

    Rao, Rekha R.; Mondy, Lisa Ann; Noble, David R.; Brunini, Victor; Roberts, Christine Cardinal; Long, Kevin Nicholas; Soehnel, Melissa Marie; Celina, Mathias C.; Wyatt, Nicholas B.; Thompson, Kyle R.; Tinsley, James

    2015-09-01

    We are studying PMDI polyurethane with a fast catalyst, such that filling and polymerization occur simultaneously. The foam is over-packed to tw ice or more of its free rise density to reach the density of interest. Our approach is to co mbine model development closely with experiments to discover new physics, to parameterize models and to validate the models once they have been developed. The model must be able to repres ent the expansion, filling, curing, and final foam properties. PMDI is chemically blown foam, wh ere carbon dioxide is pr oduced via the reaction of water and isocyanate. The isocyanate also re acts with polyol in a competing reaction, which produces the polymer. A new kinetic model is developed and implemented, which follows a simplified mathematical formalism that decouple s these two reactions. The model predicts the polymerization reaction via condensation chemis try, where vitrification and glass transition temperature evolution must be included to correctly predict this quantity. The foam gas generation kinetics are determined by tracking the molar concentration of both water and carbon dioxide. Understanding the therma l history and loads on the foam due to exothermicity and oven heating is very important to the results, since the kinetics and ma terial properties are all very sensitive to temperature. The conservation eq uations, including the e quations of motion, an energy balance, and thr ee rate equations are solved via a stabilized finite element method. We assume generalized-Newtonian rheology that is dependent on the cure, gas fraction, and temperature. The conservation equations are comb ined with a level set method to determine the location of the free surface over time. Results from the model are compared to experimental flow visualization data and post-te st CT data for the density. Seve ral geometries are investigated including a mock encapsulation part, two configur ations of a mock stru ctural part, and a bar geometry to specifically test the density model. We have found that the model predicts both average density and filling profiles well. However, it under predicts density gradients, especially in the gravity direction. Thoughts on m odel improvements are also discussed.

  7. Turbulent Flame Speeds and NOx Kinetics of HHC Fuels with Contaminants and High Dilution Levels

    SciTech Connect (OSTI)

    Petersen, Eric; Krejci, Michael; Mathieu, Olivier; Vissotski, Andrew; Ravi, Sankar; Sikes, Travis; Levacque, Anthony; Aul, Christopher; Peterson, Eric

    2011-09-30

    This progress report documents the first year of the project, from October 1, 2010 through September 30, 2011. Laminar flame speeds and ignition delay times have been measured for hydrogen and various compositions of H2/CO (syngas) at elevated pressures and elevated temperatures. Two constant-volume cylindrical vessels were used to visualize the spherical growth of the flame through the use of a schlieren optical setup to measure the laminar flame speed of the mixture. Hydrogen experiments were performed at initial pressures up to 10 atm and initial temperatures up to 443 K. A syngas composition of 50/50 was chosen to demonstrate the effect of carbon monoxide on H2-O2 chemical kinetics at standard temperature and pressures up to 10 atm. All atmospheric mixtures were diluted with standard air, while all elevated-pressure experiments were diluted with a He:O2 of 7:1 to minimize hydrodynamic instabilities. The laminar flame speed measurements of hydrogen and syngas are compared to available literature data over a wide range of equivalence ratios where good agreement can be seen with several data sets. Additionally, an improved chemical kinetics model is shown for all conditions within the current study. The model and the data presented herein agree well, which demonstrates the continual, improved accuracy of the chemical kinetics model. A high-pressure shock tube was used to measure ignition delay times for several baseline compositions of syngas at three pressures across a wide range of temperatures. The compositions of syngas (H2/CO) presented in this study include 80/20, 50/50, 40/60, 20/80, and 10/90, all of which are compared to previously published ignition delay times from a hydrogen-oxygen mixture to demonstrate the effect of carbon monoxide addition. Generally, an increase in carbon monoxide increases the ignition delay time, but there does seem to be a pressure dependency. At low temperatures and pressures higher than about 12 atm, the ignition delay times appear to be indistinguishable with an increase in carbon monoxide. However, at high temperatures the composition of H2 and CO has a strong influence on ignition delay times. Model agreement is good across the range of the study, particularly at the elevated pressures. Also an increase in carbon monoxide causes the activation energy of the mixture to decrease.

  8. Kinetics of Fe(II)-catalyzed transformation of 6-line ferrihydrite under anaerobic flow conditions

    SciTech Connect (OSTI)

    Yang, L.; Steefel, C.I.; Marcus, M.A.; Bargar, J.R.

    2010-04-01

    The readsorption of ferrous ions produced by the abiotic and microbially-mediated reductive dissolution of iron oxy-hydroxides drives a series of transformations of the host minerals. To further understand the mechanisms by which these transformations occur and their kinetics within a microporous flow environment, flow-through experiments were conducted in which capillary tubes packed with ferrihydrite-coated glass spheres were injected with inorganic Fe(II) solutions under circumneutral pH conditions at 25 C. Synchrotron X-ray diffraction was used to identify the secondary phase(s) formed and to provide data for quantitative kinetic analysis. At concentrations at and above 1.8 mM Fe(II) in the injection solution, magnetite was the only secondary phase formed (no intermediates were detected), with complete transformation following a nonlinear rate law requiring 28 hours and 150 hours of reaction at 18 and 1.8 mM Fe(II), respectively. However, when the injection solution consisted of 0.36 mM Fe(II), goethite was the predominant reaction product and formed much more slowly according to a linear rate law, while only minor magnetite was formed. When the rates are normalized based on the time to react half of the ferrihydrite on a reduced time plot, it is apparent that the 1.8 mM and 18 mM input Fe(II) experiments can be described by the same reaction mechanism, while the 0.36 input Fe(II) experiment is distinct. The analysis of the transformation kinetics suggest that the transformations involved an electron transfer reaction between the aqueous as well as sorbed Fe(II) and ferrihydrite acting as a semiconductor, rather than a simple dissolution and recrystallization mechanism. A transformation mechanism involving sorbed inner sphere Fe(II) alone is not supported, since the essentially equal coverage of sorption sites in the 18 mM and 1.8 mM Fe(II) injections cannot explain the difference in the transformation rates observed.

  9. A hybrid method for hydrodynamic-kinetic flow Part I: A particle-grid method for reducing stochastic noise in kinetic regimes

    SciTech Connect (OSTI)

    Alaia, Alessandro; Puppo, Gabriella

    2011-06-20

    In this work we present a hybrid particle-grid Monte Carlo method for the Boltzmann equation, which is characterized by a significant reduction of the stochastic noise in the kinetic regime. The hybrid method is based on a first order splitting in time to separate the transport from the relaxation step. The transport step is solved by a deterministic scheme, while a hybrid DSMC-based method is used to solve the collision step. Such a hybrid scheme is based on splitting the solution in a collisional and a non-collisional part at the beginning of the collision step, and the DSMC method is used to solve the relaxation step for the collisional part of the solution only. This is accomplished by sampling only the fraction of particles candidate for collisions from the collisional part of the solution, performing collisions as in a standard DSMC method, and then projecting the particles back onto a velocity grid to compute a piecewise constant reconstruction for the collisional part of the solution. The latter is added to a piecewise constant reconstruction of the non-collisional part of the solution, which in fact remains unchanged during the relaxation step. Numerical results show that the stochastic noise is significantly reduced at large Knudsen numbers with respect to the standard DSMC method. Indeed in this algorithm, the particle scheme is applied only on the collisional part of the solution, so only this fraction of the solution is affected by stochastic fluctuations. But since the collisional part of the solution reduces as the Knudsen number increases, stochastic noise reduces as well at large Knudsen numbers.

  10. Generation kinetics of color centers in irradiated poly(4-methyl-1-pentene)

    SciTech Connect (OSTI)

    Peng, J. S.; Li, C. L.; Lee, Sanboh; Chou, K. F.

    2011-09-15

    The transient absorbance of poly(4-methyl-1-pentene) (PMP) irradiated with gamma rays at elevated temperatures has been investigated. The absorbance in the ultraviolet and visible range increases with gamma ray dose. A bathochromic shift in transmission spectra emerges significantly upon irradiation. A first-order generation model is proposed to analyze the kinetics of color centers during annealing. The activation energy of the color center increases with increasing gamma ray dose. The equilibrium behavior of color centers in PMP is similar to that of vacancies in metals, and the formation energy of color centers in PMP decreases with increasing gamma ray dose. However, annealable color centers are not observed in this study.

  11. Kinetic simulations and reduced modeling of longitudinal sideband instabilities in non-linear electron plasma waves

    SciTech Connect (OSTI)

    Brunner, S. Hausammann, L.; Berger, R. L. Cohen, B. I.; Valeo, E. J.

    2014-10-15

    Kinetic Vlasov simulations of one-dimensional finite amplitude Electron Plasma Waves are performed in a multi-wavelength long system. A systematic study of the most unstable linear sideband mode, in particular its growth rate ? and quasi- wavenumber ?k, is carried out by scanning the amplitude and wavenumber of the initial wave. Simulation results are successfully compared against numerical and analytical solutions to the reduced model by Kruer et al. [Phys. Rev. Lett. 23, 838 (1969)] for the Trapped Particle Instability (TPI). A model recently suggested by Dodin et al. [Phys. Rev. Lett. 110, 215006 (2013)], which in addition to the TPI accounts for the so-called Negative Mass Instability because of a more detailed representation of the trapped particle dynamics, is also studied and compared with simulations.

  12. Kinetic simulations and reduced modeling of longitudinal sideband instabilities in non-linear electron plasma waves

    SciTech Connect (OSTI)

    Brunner, S.; Berger, R. L.; Cohen, B. I.; Hausammann, L.; Valeo, E. J.

    2014-10-01

    Kinetic Vlasov simulations of one-dimensional finite amplitude Electron Plasma Waves are performed in a multi-wavelength long system. A systematic study of the most unstable linear sideband mode, in particular its growth rate ? and quasi- wavenumber ?k, is carried out by scanning the amplitude and wavenumber of the initial wave. Simulation results are successfully compared against numerical and analytical solutions to the reduced model by Kruer et al. [Phys. Rev. Lett. 23, 838 (1969)] for the Trapped Particle Instability (TPI). A model recently suggested by Dodin et al. [Phys. Rev. Lett. 110, 215006 (2013)], which in addition to the TPI accounts for the so-called Negative Mass Instability because of a more detailed representation of the trapped particle dynamics, is also studied and compared with simulations.

  13. Kinetic energy distributions of sputtered neutral aluminum clusters: Al--Al{sub 6}

    SciTech Connect (OSTI)

    Coon, S.R.; Calaway, W.F.; Pellin, M.J.; Curlee, G.A.; White, J.M.

    1992-12-01

    Neutral aluminum clusters sputtered from polycrystalline aluminum were analyzed by laser postionization time-of-flight (TOF) mass spectrometry. The kinetic energy distributions of Al through Al{sub 6} were measured by a neutrals time-of-flight technique. The interpretation of laser postionization TOF data to extract velocity and energy distributions is presented. The aluminum cluster distributions are qualitatively similar to previous copper cluster distribution measurements from our laboratory. In contrast to the steep high energy tails predicted by the single- or multiple- collision models, the measured cluster distributions have high energy power law dependences in the range of E{sup {minus}3} to E{sup {minus}4.5}. Correlated collision models may explain the substantial abundance of energetic clusters that are observed in these experiments. Possible influences of cluster fragmentation on the distributions are discussed.

  14. Kinetic energy distributions of sputtered neutral aluminum clusters: Al--Al[sub 6

    SciTech Connect (OSTI)

    Coon, S.R.; Calaway, W.F.; Pellin, M.J. ); Curlee, G.A. . Dept. of Physics); White, J.M. . Dept. of Chemistry and Biochemistry)

    1992-01-01

    Neutral aluminum clusters sputtered from polycrystalline aluminum were analyzed by laser postionization time-of-flight (TOF) mass spectrometry. The kinetic energy distributions of Al through Al[sub 6] were measured by a neutrals time-of-flight technique. The interpretation of laser postionization TOF data to extract velocity and energy distributions is presented. The aluminum cluster distributions are qualitatively similar to previous copper cluster distribution measurements from our laboratory. In contrast to the steep high energy tails predicted by the single- or multiple- collision models, the measured cluster distributions have high energy power law dependences in the range of E[sup [minus]3] to E[sup [minus]4.5]. Correlated collision models may explain the substantial abundance of energetic clusters that are observed in these experiments. Possible influences of cluster fragmentation on the distributions are discussed.

  15. KINETIC STUDY OF COAL AND BIOMASS CO-PYROLYSIS USING THERMOGRAVIMETRY

    SciTech Connect (OSTI)

    Wang, Ping; Hedges, Sheila; Chaudharib, Kiran; Turtonb, Richard

    2013-10-29

    The objectives of this study are to investigate thermal behavior of coal and biomass blends in inert gas environment at low heating rates and to develop a simplified kinetic model using model fitting techniques based on TGA experimental data. Differences in thermal behavior and reactivity in co-pyrolysis of Powder River Basin (PRB) sub-bituminous coal and pelletized southern yellow pine wood sawdust blends at low heating rates are observed. Coal/wood blends have higher reactivity compared to coal alone in the lower temperature due to the high volatile matter content of wood. As heating rates increase, weight loss rates increase. The experiment data obtained from TGA has a better fit with proposed two step first order reactions model compared single first order reaction model.

  16. Photon-noise limited sensitivity in titanium nitride kinetic inductance detectors

    SciTech Connect (OSTI)

    Hubmayr, J. Beall, J.; Becker, D.; Cho, H.-M.; Hilton, G. C.; Li, D.; Pappas, D. P.; Van Lanen, J.; Vissers, M. R.; Gao, J.; Devlin, M.; Dober, B.; Groppi, C.; Mauskopf, P.; Irwin, K. D.; Wang, Y.; Wei, L. F.

    2015-02-16

    We demonstrate photon-noise limited performance at sub-millimeter wavelengths in feedhorn-coupled, microwave kinetic inductance detectors made of a TiN/Ti/TiN trilayer superconducting film, tuned to have a transition temperature of 1.4 K. Micro-machining of the silicon-on-insulator wafer backside creates a quarter-wavelength backshort optimized for efficient coupling at 250 μm. Using frequency read out and when viewing a variable temperature blackbody source, we measure device noise consistent with photon noise when the incident optical power is >0.5 pW, corresponding to noise equivalent powers >3×10{sup −17} W/√(Hz). This sensitivity makes these devices suitable for broadband photometric applications at these wavelengths.

  17. Communication. Kinetics of scavenging of small, nucleating clusters. First nucleation theorem and sum rules

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Malila, Jussi; McGraw, Robert; Laaksonen, Ari; Lehtinen, Kari E. J.

    2015-01-07

    Despite recent advances in monitoring nucleation from a vapor at close-to-molecular resolution, the identity of the critical cluster, forming the bottleneck for the nucleation process, remains elusive. During past twenty years, the first nucleation theorem has been often used to extract the size of the critical cluster from nucleation rate measurements. However, derivations of the first nucleation theorem invoke certain questionable assumptions that may fail, e.g., in the case of atmospheric new particle formation, including absence of subcritical cluster losses and heterogeneous nucleation on pre-existing nanoparticles. Here we extend the kinetic derivation of the first nucleation theorem to give amore » general framework to include such processes, yielding sum rules connecting the size dependent particle formation and loss rates to the corresponding loss-free nucleation rate and the apparent critical size from a naïve application of the first nucleation theorem that neglects them.« less

  18. Improvements in Mixing Time and Mixing Uniformity in Devices Designed for Studies of Protein Folding Kinetics

    SciTech Connect (OSTI)

    Yao, Shuhuai [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bakajin, Olgica [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2007-08-01

    Using a microfluidic laminar flow mixer designed for studies of protein folding kinetics, we demonstrate a mixing time of 1 +/- 1 micros with sample consumption on the order of femtomoles. We recognize two limitations of previously proposed designs: (1) size and shape of the mixing region, which limits mixing uniformity and (2) the formation of Dean vortices at high flow rates, which limits the mixing time. We address these limitations by using a narrow shape-optimized nozzle and by reducing the bend of the side channel streamlines. The final design, which combines both of these features, achieves the best performance. We quantified the mixing performance of the different designs by numerical simulation of coupled Navier-Stokes and convection-diffusion equations and experiments using fluorescence resonance energy-transfer (FRET)-labeled DNA.

  19. Retorting of oil shale followed by solvent extraction of spent shale: Experiment and kinetic analysis

    SciTech Connect (OSTI)

    Khraisha, Y.H.

    2000-05-01

    Samples of El-Lajjun oil shale were thermally decomposed in a laboratory retort system under a slow heating rate (0.07 K/s) up to a maximum temperature of 698--773 K. After decomposition, 0.02 kg of spent shale was extracted by chloroform in a Soxhlet extraction unit for 2 h to investigate the ultimate amount of shale oil that could be produced. The retorting results indicate an increase in the oil yields from 3.24% to 9.77% of oil shale feed with retorting temperature, while the extraction results show a decrease in oil yields from 8.10% to 3.32% of spent shale. The analysis of the data according to the global first-order model for isothermal and nonisothermal conditions shows kinetic parameters close to those reported in literature.

  20. Titanium tritide radioisotope heat source development : palladium-coated titanium hydriding kinetics and tritium loading tests.

    SciTech Connect (OSTI)

    Van Blarigan, Peter; Shugard, Andrew D.; Walters, R. Tom

    2012-01-01

    We have found that a 180 nm palladium coating enables titanium to be loaded with hydrogen isotopes without the typical 400-500 C vacuum activation step. The hydriding kinetics of Pd coated Ti can be described by the Mintz-Bloch adherent film model, where the rate of hydrogen absorption is controlled by diffusion through an adherent metal-hydride layer. Hydriding rate constants of Pd coated and vacuum activated Ti were found to be very similar. In addition, deuterium/tritium loading experiments were done on stacks of Pd coated Ti foil in a representative-size radioisotope heat source vessel. The experiments demonstrated that such a vessel could be loaded completely, at temperatures below 300 C, in less than 10 hours, using existing department-of-energy tritium handling infrastructure.

  1. The Path of Carbon in Photosynthesis XVI. Kinetic Relationships of the Intermediates in Steady State Photosynthesis

    DOE R&D Accomplishments [OSTI]

    Benson, A. A.; Kawaguchi, S.; Hayes, P.; Calvin, M.

    1952-06-05

    A kinetic study of the accumulation of C{sup 14} in the intermediates of steady state photosynthesis in C{sup 14}O{sub 2} provides information regarding the sequence of reactions involved. The work described applied the radio-chromatographic technique for analysis of the labeled early products. The simultaneous carboxylation reaction resulting in malic acid as well as phosphoglycerate is demonstrated in experiments at high light intensity. A comparison of radioactivities in a number of phosphorylated sugars as a function of time reveals concurrent synthesis of fructose and sedoheptulose phosphates followed by that of ribulose phosphates and later by that of glucose phosphates. The possibility that the cleavage of C{sub 4} compounds to C{sub 2} carbon dioxide acceptors may involve C{sub 7} and C{sub 5} sugars and evidence for this mechanism is presented.

  2. Impact of Biodiesel on the Oxidation Kinetics and Morphology of Diesel Particulate

    SciTech Connect (OSTI)

    Strzelec, Andrea; Toops, Todd J; Daw, C Stuart

    2011-01-01

    We compare the oxidation characteristics of four different diesel particulates generated with a modern light-duty engine. The four particulates represent engine fueling with conventional ultra-low sulfur diesel (ULSD), biodiesel, and two intermediate blends of these fuels. The comparisons discussed here are based on complementary measurements implemented in a laboratory micro-reactor, including temperature programmed desorption and oxidation, pulsed isothermal oxidation, and BET surface area. From these measurements we have derived models that are consistent with the observed oxidation reactivity differences. When accessible surface area effects are properly accounted for, the oxidation kinetics of the fixed carbon components were found to consistently exhibit an Arrhenius activation energy of 113 6 kJ/mol. Release of volatile carbon from the as-collected particulate appears to follow a temperaturedependent rate law.

  3. Kinetic Modeling of Gasoline Surrogate Components and Mixtures under Engine Conditions

    SciTech Connect (OSTI)

    Mehl, M; Pitz, W J; Westbrook, C K; Curran, H J

    2010-01-11

    Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, an improved version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multicomponent gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines (3-50 atm, 650-1200K, stoichiometric fuel/air mixtures). Simulation results are discussed focusing attention on the mixing effects of the fuel components.

  4. Horn-coupled, commercially-fabricated aluminum lumped-element kinetic inductance detectors for millimeter wavelengths

    SciTech Connect (OSTI)

    McCarrick, H. Flanigan, D.; Jones, G.; Johnson, B. R.; Araujo, D.; Limon, M.; Luu, V.; Miller, A.; Ade, P.; Doyle, S.; Tucker, C.; Bradford, K.; Che, G.; Cantor, R.; Day, P.; Leduc, H.; Mauskopf, P.; Mroczkowski, T.; Zmuidzinas, J.

    2014-12-15

    We discuss the design, fabrication, and testing of prototype horn-coupled, lumped-element kinetic inductance detectors (LEKIDs) designed for cosmic microwave background studies. The LEKIDs are made from a thin aluminum film deposited on a silicon wafer and patterned using standard photolithographic techniques at STAR Cryoelectronics, a commercial device foundry. We fabricated 20-element arrays, optimized for a spectral band centered on 150 GHz, to test the sensitivity and yield of the devices as well as the multiplexing scheme. We characterized the detectors in two configurations. First, the detectors were tested in a dark environment with the horn apertures covered, and second, the horn apertures were pointed towards a beam-filling cryogenic blackbody load. These tests show that the multiplexing scheme is robust and scalable, the yield across multiple LEKID arrays is 91%, and the measured noise-equivalent temperatures for a 4 K optical load are in the range 266 ?K?(s)

  5. Kinetics of hydride front in Zircaloy-2 and H release from a fractional hydrided surface

    SciTech Connect (OSTI)

    Diaz, M.; Gonzalez-Gonzalez, A.; Moya, J. S.; Remartinez, B.; Perez, S.; Sacedon, J. L.

    2009-07-15

    The authors study the hydriding process on commercial nuclear fuel claddings from their inner surface using an ultrahigh vacuum method. The method allows determining the incubation and failure times of the fuel claddings, as well as the dissipated energy and the partial pressure of the desorbed H{sub 2} from the outer surface of fuel claddings during the hydriding process. The correlation between the hydriding dissipated energy and the amount of zirconium hydride (formed at different stages of the hydriding process) leads to a near t{sup 1/2} potential law corresponding to the time scaling of the reaction for the majority of the tested samples. The calibrated relation between energy and hydride thickness allows one to calculate the enthalpy of the {delta}-ZrH{sub 1.5} phase. The measured H{sub 2} desorption from the external surface is in agreement with a proposed kinetic desorption model from the hydrides precipitated at the surface.

  6. (Competitive ion kinetics in director mass spectrometric organic speciation). Progress report

    SciTech Connect (OSTI)

    Sieck, L.W.

    1986-01-01

    Essentially all of the completed/in progress studies during the last reporting period have involved the NBS pulsed electron beam high pressure mass spectrometer. Three distinct areas of research are recognizable; (1) determinations of binding energies and entropies for association and cluster ions, which is accomplished by measuring the temperature dependence of the equilibrium A/sup +/ or A/sup -/ + B in equilibrium A/sup +/.B or A/sup -/.B, (2) measurement of unimolecular rate constants for the thermal decomposition (pyrolysis of protonated organic molecules, and (3) evaluation of proton affinities and gas phase acidities via measurement of variable-temperature equilibria of the type AH/sup +/ + B in equilibrium BH/sup +/ + A and A/sup -/ + BH in equilibrium AH + B/sup -/. The various systems and classes of molecules chosen for study were those deemed most likely to provide fundamental new information on ion kinetics, ionic stabilities and ionic reaction mechanisms.

  7. Surfkin: A program to solve transient and steady state heterogeneous reaction kinetics

    SciTech Connect (OSTI)

    COLTRIN,MICHAEL E.; WIXOM,RYAN R.; DANDY,DAVID S.

    2000-05-01

    Heterogeneous chemical reactions occurring at a gas/surface interface are fundamental in a variety of important applications, such as combustion, catalysis, chemical vapor deposition and plasma processing. Detailed simulation of these processes may involve complex, coupled fluid flow, heat transfer, gas-phase chemistry, in addition to heterogeneous reaction chemistry. This report documents the Surfkin program, which simulates the kinetics of heterogeneous chemical reactions. The program is designed for use with the Chemkin and Surface Chemkin (heterogeneous chemistry) programs. It calculates time-dependent or steady state surface site fractions and bulk-species production/destruction rates. The surface temperature may be specified as a function of time to simulate a temperature-programmed desorption experiment, for example. This report serves as a user's manual for the program, explaining the required input and format of the output. Two detailed example problems are included to further illustrate the use of this program.

  8. Surface kinetic model for isotopic and trace element fractionation during precipitation of calcite from aqueous solution

    SciTech Connect (OSTI)

    DePaolo, D.

    2010-10-15

    A surface reaction kinetic model is developed for predicting Ca isotope fractionation and metal/Ca ratios of calcite as a function of rate of precipitation from aqueous solution. The model is based on the requirements for dynamic equilibrium; i.e. proximity to equilibrium conditions is determined by the ratio of the net precipitation rate (R{sub p}) to the gross forward precipitation rate (R{sub f}), for conditions where ionic transport to the growing crystal surface is not rate-limiting. The value of R{sub p} has been experimentally measured under varying conditions, but the magnitude of R{sub f} is not generally known, and may depend on several factors. It is posited that, for systems with no trace constituents that alter the surface chemistry, R{sub f} can be estimated from the bulk far-from-equilibrium dissolution rate of calcite (R{sub b} or k{sub b}), since at equilibrium R{sub f} = R{sub b}, and R{sub p} = 0. Hence it can be inferred that R{sub f} {approx} R{sub p} + R{sub b}. The dissolution rate of pure calcite is measureable and is known to be a function of temperature and pH. At given temperature and pH, equilibrium precipitation is approached when R{sub p} (= R{sub f} - R{sub b}) << R{sub b}. For precipitation rates high enough that R{sub p} >> R{sub b}, both isotopic and trace element partitioning are controlled by the kinetics of ion attachment to the mineral surface, which tend to favor more rapid incorporation of the light isotopes of Ca and discriminate weakly between trace metals and Ca. With varying precipitation rate, a transition region between equilibrium and kinetic control occurs near R{sub p} {approx} R{sub b} for Ca isotopic fractionation. According to this model, Ca isotopic data can be used to estimate R{sub f} for calcite precipitation. Mechanistic models for calcite precipitation indicate that the molecular exchange rate is not constant at constant T and pH, but rather is dependent also on solution saturation state and hence R{sub p}. Allowing R{sub b} to vary as R{sub p}{sup 1/2}, consistent with available precipitation rate studies, produces a better fit to some trace element and isotopic data than a model where R{sub b} is constant. This model can account for most of the experimental data in the literature on the dependence of {sup 44}Ca/{sup 40}Ca and metal/Ca fractionation in calcite as a function of precipitation rate and temperature, and also accounts for {sup 18}O/{sup 16}O variations with some assumptions. The apparent temperature dependence of Ca isotope fractionation in calcite may stem from the dependence of R{sub b} on temperature; there should be analogous pH dependence at pH < 6. The proposed model may be valuable for predicting the behavior of isotopic and trace element fractionation for a range of elements of interest in low-temperature aqueous geochemistry. The theory presented is based on measureable thermo-kinetic parameters in contrast to models that equire hyper-fast diffusivity in near-surface layers of the solid.

  9. Kinetic Model for the Radical Degradation of Tri-Halonitromethane Disinfection Byproducts in Water

    SciTech Connect (OSTI)

    Stephen P. Mezyk; Bruce J. Mincher; William J. Cooper; S. Kirkham Cole; Robert V. Fox; Pieror R. Gardinali

    2012-10-01

    The halonitromethanes (HNMs) are byproducts of the ozonation and chlorine/chloramine treatment of drinking waters. Although typically occurring at low concentrations HNMs have high cytotoxicity and mutagenicity, and may therefore represent a significant human health hazard. In this study, we have investigated the radical based mineralization of fully-halogenated HNMs in water using the congeners bromodichloronitromethane and chlorodibromonitromethane. We have combined absolute reaction rate constants for their reactions with the hydroxyl radical and the hydrated electron as measured by electron pulse radiolysis and analytical measurements of stable product concentrations obtained by 60Co steady-state radiolysis with a kinetic computer model that includes water radiolysis reactions and halide/nitrogen oxide radical chemistry to fully elucidate the reaction pathways of these HNMs. These results are compared to our previous similar study of the fully chlorinated HNM chloropicrin. The full optimized computer model, suitable for predicting the behavior of this class of compounds in irradiated drinking water is provided.

  10. Communication. Kinetics of scavenging of small, nucleating clusters. First nucleation theorem and sum rules

    SciTech Connect (OSTI)

    Malila, Jussi; McGraw, Robert; Laaksonen, Ari; Lehtinen, Kari E. J.

    2015-01-07

    Despite recent advances in monitoring nucleation from a vapor at close-to-molecular resolution, the identity of the critical cluster, forming the bottleneck for the nucleation process, remains elusive. During past twenty years, the first nucleation theorem has been often used to extract the size of the critical cluster from nucleation rate measurements. However, derivations of the first nucleation theorem invoke certain questionable assumptions that may fail, e.g., in the case of atmospheric new particle formation, including absence of subcritical cluster losses and heterogeneous nucleation on pre-existing nanoparticles. Here we extend the kinetic derivation of the first nucleation theorem to give a general framework to include such processes, yielding sum rules connecting the size dependent particle formation and loss rates to the corresponding loss-free nucleation rate and the apparent critical size from a nave application of the first nucleation theorem that neglects them.

  11. Sensitivity of natural gas HCCI combustion to fuel and operating parameters using detailed kinetic modeling

    SciTech Connect (OSTI)

    Aceves, S; Dibble, R; Flowers, D; Smith, J R; Westbrook, C K

    1999-07-19

    This paper uses the HCT (Hydrodynamics, Chemistry and Transport) chemical kinetics code to analyze natural gas HCCI combustion in an engine. The HCT code has been modified to better represent the conditions existing inside an engine, including a wall heat transfer correlation. Combustion control and low power output per displacement remain as two of the biggest challenges to obtaining satisfactory performance out of an HCCI engine, and these are addressed in this paper. The paper considers the effect of natural gas composition on HCCI combustion, and then explores three control strategies for HCCI engines: DME (dimethyl ether) addition, intake heating and hot EGR addition. The results show that HCCI combustion is sensitive to natural gas composition, and an active control may be required to compensate for possible changes in composition. The three control strategies being considered have a significant effect in changing the combustion parameters for the engine, and should be able to control HCCI combustion.

  12. Kinetically balanced Gaussian basis-set approach to relativistic Compton profiles of atoms

    SciTech Connect (OSTI)

    Jaiswal, Prerit; Shukla, Alok

    2007-02-15

    Atomic Compton profiles (CPs) are a very important property which provide us information about the momentum distribution of atomic electrons. Therefore, for CPs of heavy atoms, relativistic effects are expected to be important, warranting a relativistic treatment of the problem. In this paper, we present an efficient approach aimed at ab initio calculations of atomic CPs within a Dirac-Hartree-Fock (DHF) formalism, employing kinetically balanced Gaussian basis functions. The approach is used to compute the CPs of noble gases ranging from He to Rn, and the results have been compared to the experimental and other theoretical data, wherever possible. The influence of the quality of the basis set on the calculated CPs has also been systematically investigated.

  13. Progress with the COGENT Edge Kinetic Code: Implementing the Fokker-Plank Collision Operator

    SciTech Connect (OSTI)

    Dorf, M. A.; Cohen, R. H.; Dorr, M.; Hittinger, J.; Rognlien, T. D.

    2014-06-20

    Here, COGENT is a continuum gyrokinetic code for edge plasma simulations being developed by the Edge Simulation Laboratory collaboration. The code is distinguished by application of a fourth-order finite-volume (conservative) discretization, and mapped multiblock grid technology to handle the geometric complexity of the tokamak edge. The distribution function F is discretized in v∥ – μ (parallel velocity – magnetic moment) velocity coordinates, and the code presently solves an axisymmetric full-f gyro-kinetic equation coupled to the long-wavelength limit of the gyro-Poisson equation. COGENT capabilities are extended by implementing the fully nonlinear Fokker-Plank operator to model Coulomb collisions in magnetized edge plasmas. The corresponding Rosenbluth potentials are computed by making use of a finite-difference scheme and multipole-expansion boundary conditions. Details of the numerical algorithms and results of the initial verification studies are discussed. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

  14. Physically consistent simulation of mesoscale chemical kinetics: The non-negative FIS-{alpha} method

    SciTech Connect (OSTI)

    Dana, Saswati, E-mail: saswatid@rishi.serc.iisc.ernet.in [Supercomputer Education and Research Centre, Indian Institute of Science, Bangalore 560012 (India); Raha, Soumyendu, E-mail: raha@serc.iisc.ernet.in [Supercomputer Education and Research Centre, Indian Institute of Science, Bangalore 560012 (India)

    2011-10-01

    Biochemical pathways involving chemical kinetics in medium concentrations (i.e., at mesoscale) of the reacting molecules can be approximated as chemical Langevin equations (CLE) systems. We address the physically consistent non-negative simulation of the CLE sample paths as well as the issue of non-Lipschitz diffusion coefficients when a species approaches depletion and any stiffness due to faster reactions. The non-negative Fully Implicit Stochastic {alpha} (FIS {alpha}) method in which stopped reaction channels due to depleted reactants are deleted until a reactant concentration rises again, for non-negativity preservation and in which a positive definite Jacobian is maintained to deal with possible stiffness, is proposed and analysed. The method is illustrated with the computation of active Protein Kinase C response in the Protein Kinase C pathway.

  15. Billion-atom synchronous parallel kinetic Monte Carlo simulations of critical 3D Ising systems

    SciTech Connect (OSTI)

    Martinez, E.; Monasterio, P.R.; Marian, J.

    2011-02-20

    An extension of the synchronous parallel kinetic Monte Carlo (spkMC) algorithm developed by Martinez et al. [J. Comp. Phys. 227 (2008) 3804] to discrete lattices is presented. The method solves the master equation synchronously by recourse to null events that keep all processors' time clocks current in a global sense. Boundary conflicts are resolved by adopting a chessboard decomposition into non-interacting sublattices. We find that the bias introduced by the spatial correlations attendant to the sublattice decomposition is within the standard deviation of serial calculations, which confirms the statistical validity of our algorithm. We have analyzed the parallel efficiency of spkMC and find that it scales consistently with problem size and sublattice partition. We apply the method to the calculation of scale-dependent critical exponents in billion-atom 3D Ising systems, with very good agreement with state-of-the-art multispin simulations.

  16. Kinetic control of structural and magnetic states in LuBaCo4O7.

    SciTech Connect (OSTI)

    Avci, S.; Chmaissem, O.; Zheng, H.; Huq, A.; Khalyavin, D.; Stephens, P.; Suchomel, M.; Manuel, P.; Mitchell, J.

    2012-01-01

    The RBaCo{sub 4}O{sub 7} (R = Ca, Y, Tb, Ho, Tm, Yb, Lu) compounds provide a novel topology for studying the competition between triangular geometry and magnetic order. Here, we report the structural and magnetic behavior of the Lu member of this series via neutron and synchrotron x-ray diffraction, magnetization, and resistivity measurements. We determined sequential phase transitions and a strong competition between a stable and a metastable low-temperature state that critically depends on controlled cooling rates and the associated heat removal kinetics. No evidence for long-range ordered magnetism was detected by neutron diffraction at any temperature. However, very slow spin dynamics are evidenced by time-dependent neutron diffraction measurements and can be explained by several competing magnetic phases with incommensurate short-range correlations coexisting in this material.

  17. RADIAL DEPENDENCE OF THE FREQUENCY BREAK BETWEEN FLUID AND KINETIC SCALES IN THE SOLAR WIND FLUCTUATIONS

    SciTech Connect (OSTI)

    Bruno, R.; Trenchi, L.

    2014-06-01

    We investigate the radial dependence of the spectral break separating the inertial from the dissipation range in power density spectra of interplanetary magnetic field fluctuations, between 0.42 and 5.3 AU, during radial alignments between MESSENGER and WIND for the inner heliosphere and between WIND and ULYSSES for the outer heliosphere. We found that the spectral break moves to higher and higher frequencies as the heliocentric distance decreases. The radial dependence of the corresponding wavenumber is of the kind κ {sub b} ∼ R {sup –1.08}, in good agreement with that of the wavenumber derived from the linear resonance condition for proton cyclotron damping. These results support conclusions from previous studies which suggest that a cyclotron-resonant dissipation mechanism must participate in the spectral cascade together with other possible kinetic noncyclotron-resonant mechanisms.

  18. Thermodynamics and Kinetics of Advanced Separations Systems FY 2010 Summary Report

    SciTech Connect (OSTI)

    Leigh R. Martin; Peter R. Zalupski

    2010-09-01

    This report presents a summary of the work performed in the area of thermodynamics and kinetics of advanced separations systems under the Fuel Cycle Research and Development (FCR&D) program during FY 2010. Thermodynamic investigations into metal extraction dependencies on lactate and HDEHP have been performed. These metal distribution studies indicate a substantial deviation from the expected behavior at conditions that are typical of TALSPEAK process operational platform. These studies also identify that no thermodynamically stable mixed complexes exist in the aqueous solutions and increasing the complexity of the organic medium appears to influence the observed deviations. Following on from this, the first calorimetric measurement of the heat of extraction of americium across a liquid-liquid boundary was performed.

  19. Isotope effects on desorption kinetics of hydrogen isotopes implanted into stainless steel by glow discharge

    SciTech Connect (OSTI)

    Matsuyama, M.; Kondo, M.; Noda, N.; Tanaka, M.; Nishimura, K.

    2015-03-15

    In a fusion device the control of fuel particles implies to know the desorption rate of hydrogen isotopes by the plasma-facing materials. In this paper desorption kinetics of hydrogen isotopes implanted into type 316L stainless steel by glow discharge have been studied by experiment and numerical calculation. The temperature of a maximum desorption rate depends on glow discharge time and heating rate. Desorption spectra observed under various experimental conditions have been successfully reproduced by numerical simulations that are based on a diffusion-limited process. It is suggested, therefore, that desorption rate of a hydrogen isotope implanted into the stainless steel is limited by a diffusion process of hydrogen isotope atoms in bulk. Furthermore, small isotope effects were observed for the diffusion process of hydrogen isotope atoms. (authors)

  20. Nonlinear interaction of proton whistler with kinetic Alfvn wave to study solar wind turbulence

    SciTech Connect (OSTI)

    Goyal, R.; Sharma, R. P.; Goldstein, M. L.; Dwivedi, N. K.

    2013-12-15

    This paper presents the nonlinear interaction between small but finite amplitude kinetic Alfvn wave (KAW) and proton whistler wave using two-fluid model in intermediate beta plasma, applicable to solar wind. The nonlinearity is introduced by modification in the background density. This change in density is attributed to the nonlinear ponderomotive force due to KAW. The solutions of the model equations, governing the nonlinear interaction (and its effect on the formation of localized structures), have been obtained using semi-analytical method in solar wind at 1AU. It is concluded that the KAW properties significantly affect the threshold field required for the filament formation and their critical size (for proton whistler). The magnetic and electric field power spectra have been obtained and their relevance with the recent observations of solar wind turbulence by Cluster spacecraft has been pointed out.

  1. Spectral evolution of two-dimensional kinetic plasma turbulence in the wavenumber-frequency domain

    SciTech Connect (OSTI)

    Comi?el, H.; Institute for Space Sciences, Atomi?tilor 409, P.O. Box MG-23, Bucharest-M?gurele RO-077125 ; Verscharen, D.; Narita, Y.; Motschmann, U.; Deutsches Zentrum fr Luft- und Raumfahrt, Institut fr Planetenforschung, Rutherfordstr. 2, D-12489 Berlin

    2013-09-15

    We present a method for studying the evolution of plasma turbulence by tracking dispersion relations in the energy spectrum in the wavenumber-frequency domain. We apply hybrid plasma simulations in a simplified two-dimensional geometry to demonstrate our method and its applicability to plasma turbulence in the ion kinetic regime. We identify four dispersion relations: ion-Bernstein waves, oblique whistler waves, oblique Alfvn/ion-cyclotron waves, and a zero-frequency mode. The energy partition and frequency broadening are evaluated for these modes. The method allows us to determine the evolution of decaying plasma turbulence in our restricted geometry and shows that it cascades along the dispersion relations during the early phase with an increasing broadening around the dispersion relations.

  2. Kinetics programs for simulation of tropospheric photochemistry on the global scale

    SciTech Connect (OSTI)

    Elliott, S.; Kao, C.Y.J.; Turco, R.P.; Zhao, X.P.

    1993-08-01

    The study of tropospheric kinetics underlies global change because key greenhouse gases are photochemically active. Modeling of tropospheric chemistry on a global scale is essential because some indirect greenhouse gases are short-lived and interact in a non-linear fashion. It is also extremely challenging, however; the global change grid is extensive in both the physical and temporal domains, and critical lower atmospheric species include the organics and their oxidized derivatives, which are numerous. Several types of optimization may be incorporated into kinetics modules to enhance their ability to simulate the complete lower atmospheric gas phase chemical system. (1) The photochemical integrator can be accelerated by avoiding matrix and iterative solutions and by establishing families. Accuracy and mass conservation are sacrificed in the absence of iteration, but atom balancing is restorable post hoc. (2) Chemistry can be arranged upon the massive grid to exploit parallel processing, and solutions to its continuity equations can be automated to permit experimentation with species and reaction lists or family definitions. Costs in programming effort will be incurred in these cases. (3) Complex hydrocarbon decay sequences can be streamlined either through structural lumping methods descended from smog investigations, which require considerable calibration, or by defining surrogates for classes of compounds, with a loss in constituent detail. From among the available options, the most advantageous permutations will vary with the specific nature of any eventual global scale study, and there is likely to be demand for many approaches. Tracer transport codes serve as a foundation upon which tropospheric chemistry packages will be tested. Encroachment of the NO{sub x} sphere of influence upon tropical rain forests and the upper free troposphere are two examples of specific problems to which full three-dimensional chemical simulations might be applied.

  3. Goal-oriented sensitivity analysis for lattice kinetic Monte Carlo simulations

    SciTech Connect (OSTI)

    Arampatzis, Georgios; Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003 ; Katsoulakis, Markos A.

    2014-03-28

    In this paper we propose a new class of coupling methods for the sensitivity analysis of high dimensional stochastic systems and in particular for lattice Kinetic Monte Carlo (KMC). Sensitivity analysis for stochastic systems is typically based on approximating continuous derivatives with respect to model parameters by the mean value of samples from a finite difference scheme. Instead of using independent samples the proposed algorithm reduces the variance of the estimator by developing a strongly correlated-coupled- stochastic process for both the perturbed and unperturbed stochastic processes, defined in a common state space. The novelty of our construction is that the new coupled process depends on the targeted observables, e.g., coverage, Hamiltonian, spatial correlations, surface roughness, etc., hence we refer to the proposed method as goal-oriented sensitivity analysis. In particular, the rates of the coupled Continuous Time Markov Chain are obtained as solutions to a goal-oriented optimization problem, depending on the observable of interest, by considering the minimization functional of the corresponding variance. We show that this functional can be used as a diagnostic tool for the design and evaluation of different classes of couplings. Furthermore, the resulting KMC sensitivity algorithm has an easy implementation that is based on the BortzKalosLebowitz algorithm's philosophy, where events are divided in classes depending on level sets of the observable of interest. Finally, we demonstrate in several examples including adsorption, desorption, and diffusion Kinetic Monte Carlo that for the same confidence interval and observable, the proposed goal-oriented algorithm can be two orders of magnitude faster than existing coupling algorithms for spatial KMC such as the Common Random Number approach. We also provide a complete implementation of the proposed sensitivity analysis algorithms, including various spatial KMC examples, in a supplementary MATLAB source code.

  4. DENSE MULTIPHASE FLOW SIMULATION: CONTINUUM MODEL FOR POLY-DISPERSED SYSTEMS USING KINETIC THEORY

    SciTech Connect (OSTI)

    Moses Bogere

    2011-08-31

    The overall objective of the project was to verify the applicability of the FCMOM approach to the kinetic equations describing the particle flow dynamics. For monodispersed systems the fundamental equation governing the particle flow dynamics is the Boltzmann equation. During the project, the FCMOM was successfully applied to several homogeneous and in-homogeneous problems in different flow regimes, demonstrating that the FCMOM has the potential to be used to solve efficiently the Boltzmann equation. However, some relevant issues still need to be resolved, i.e. the homogeneous cooling problem (inelastic particles cases) and the transition between different regimes. In this report, the results obtained in homogeneous conditions are discussed first. Then a discussion of the validation results for in-homogeneous conditions is provided. And finally, a discussion will be provided about the transition between different regimes. Alongside the work on development of FCMOM approach studies were undertaken in order to provide insights into anisotropy or particles kinetics in riser hydrodynamics. This report includes results of studies of multiphase flow with unequal granular temperatures and analysis of momentum re-distribution in risers due to particle-particle and fluid-particle interactions. The study of multiphase flow with unequal granular temperatures entailed both simulation and experimental studies of two particles sizes in a riser and, a brief discussion of what was accomplished will be provided. And finally, a discussion of the analysis done on momentum re-distribution of gas-particles flow in risers will be provided. In particular a discussion of the remaining work needed in order to improve accuracy and predictability of riser hydrodynamics based on two-fluid models and how they can be used to model segregation in risers.

  5. Fundamental and semi-global kinetic mechanisms for hydrocarbon combustion. Final report, March 1977-October 1980

    SciTech Connect (OSTI)

    Dryer, F L; Glassman, I; Brezinsky, K

    1981-03-01

    Over the past three and one half years, substantial research efforts of the Princeton Fuels Research Group have been directed towards the development of simplified mechanisms which would accurately describe the oxidation of hydrocarbons fuels. The objectives of this combustion research included the study of semi-empirical modeling (that is an overall description) of the chemical kinetic mechanisms of simple hydrocarbon fuels. Such fuels include the alkanes: ethane, propane, butane, hexane and octane as well as the critically important alkenes: ethene, propene and butene. As an extension to this work, the study of the detailed radical species characteristics of combustion systems was initiated as another major aspect of the program, with emphasis on the role of the OH and HO/sub 2/ radicals. Finally, the studies of important alternative fuel problems linked the program to longer range approaches to the energy supply question. Studies of alternative fuels composed the major elements of this area of the program. The efforts on methanol research were completed, and while the aromatics aspects of the DOE work have been a direct extension of efforts supported by the Air Force Office of Scientific Research, they represented a significant part of the overall research effort. The emphasis in the proposed program is to provide further fundamental understanding of the oxidation of hydrocarbon fuels which will be useful in guiding engineering approaches. Although the scope of program ranges from the fundamentals of chemical kinetics to that of alternative fuel combustion, the objective in mind is to provide insight and guidance to the understanding of practical combustion environments. The key to our approach has been our understanding of the fundamental combustion chemistry and its relation to the important practical combustion problems which exist in implementing energy efficient, alternate fuels technologies.

  6. Chemical kinetic modeling of high pressure propane oxidation and comparison to experimental results

    SciTech Connect (OSTI)

    Koert, D.N.; Pitz, W.J.; Bozzelli, J.W.; Cernansky, N.P.

    1995-11-08

    A pressure dependent kinetic mechanism for propane oxidation is developed and compared to experimental data from a high pressure flow reactor. The experiment conditions range from 10--15 atm, 650--800 K, and were performed at a residence time of 200 {micro}s for propane-air mixtures at an equivalence ratio of 0.4. The experimental results include data on negative temperature coefficient (NTC) behavior, where the chemistry describing this phenomena is considered critical in understanding automotive engine knock and cool flame oscillations. Results of the numerical model are compared to a spectrum of stable species profiles sampled from the flow reactor. Rate constants and product channels for the reaction of propyl radicals, hydroperoxy-propyl radicals and important isomers with O{sub 2} were estimated using thermodynamic properties, with multifrequency quantum Kassel Theory for k(E) coupled with modified strong collision analysis for fall-off. Results of the chemical kinetic model show an NTC region over nearly the same temperature regime as observed in the experiments. The model simulates properly the production of many of the major and minor species observed in the experiments. Numerical simulations show many of the key reactions involving propylperoxy radicals are in partial equilibrium at 10--15 atm. This indicates that their relative concentrations are controlled by a combination of thermochemistry and rate of minor reaction channels (bleed reactions) rather than primary reaction rates. This suggests that thermodynamic parameters of the oxygenated species, which govern equilibrium concentrations, are important. The modeling results show propyl radical and hydroperoxy-propyl radicals reaction with O{sub 2} proceeds, primarily, through thermalized adducts, not chemically activated channels.

  7. Kinetic simulation of the O-X conversion process in dense magnetized plasmas

    SciTech Connect (OSTI)

    Ali Asgarian, M. [Physics Department, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of) [Physics Department, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824-1226 (United States); Verboncoeur, J. P. [Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824-1226 (United States)] [Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824-1226 (United States); Parvazian, A. [Physics Department, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)] [Physics Department, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of); Trines, R. [STFC Rutherford Appleton Laboratory, Didcot (United Kingdom)] [STFC Rutherford Appleton Laboratory, Didcot (United Kingdom)

    2013-10-15

    One scheme for heating a dense magnetized plasma core, such as in a tokamak, involves launching an ordinary (O) electromagnetic wave at the low density edge. It is converted to a reflected extraordinary (X) electromagnetic wave under certain conditions, and then transformed into an electron Bernstein wave able to reach high density regions inaccessible to most other waves. The O-X mode conversion is important in heating and diagnostic processes in different devices such as tokamaks, stellarators, and some types of pinches. The goal of this study has been to demonstrate that the kinetic particle-in-cell (PIC) scheme is suitable for modeling the O-X conversion process as the first step toward a more complete simulation of O-X-B heating. The O-X process is considered and simulated with a kinetic particle model for parameters of the TJ-II stellarator using the PIC code, XOOPIC. This code is able to model the non-monotonic density and the magnetic profile of the TJ-II stellarator. It can also statistically represent the self-consistent distribution function of the plasma, which has not been possible in previous fluid models. By considering the electric and magnetic components of launched and reflected waves, the O-mode and X-mode waves can be detected, and the O-X conversion can be demonstrated. In this work, the optimum angle for conversion efficiency, as predicted by the previous theory and experimentally confirmed, is used. Via considering the power of the launched O-mode wave and the converted X-mode wave, the efficiency of 63% for O-X conversion for the optimum theoretical launch angle of 47{sup ?} is obtained, which is in good agreement with efficiencies computed via full-wave simulations.

  8. Kinetics and dynamic modelling of batch anaerobic digestion of municipal solid waste in a stirred reactor

    SciTech Connect (OSTI)

    Nopharatana, Annop; Pullammanappallil, Pratap C.; Clarke, William P.

    2007-07-01

    A series of batch, slurry anaerobic digestion experiments were performed where the soluble and insoluble fractions, and unwashed MSW were separately digested in a 200 l stirred stainless steel vessel at a pH of 7.2 and a temperature of 38 deg. C. It was found that 7% of the total MSW COD was readily soluble, of which 80% was converted to biogas; 50% of the insoluble fraction was solubilised, of this only 80% was converted to biogas. The rate of digesting the insoluble fraction was about four times slower than the rate of digesting the soluble fraction; 48% of the total COD was converted to biogas and 40% of the total nitrogen was converted to ammonia. Soluble and insoluble fractions were broken down simultaneously. The minimum time to convert 95% of the degradable fraction to biogas was 20 days. The lag phase for the degradation of insoluble fraction of MSW can be overcome by acclimatising the culture with the soluble fraction. The rate of digestion and the methane yield was not affected by particle size (within the range of 2-50 mm). A dynamic model was developed to describe batch digestion of MSW. The parameters of the model were estimated using data from the separate digestion of soluble and insoluble fractions and validated against data from the digestion of unwashed MSW. Trends in the specific aceticlastic and formate-utilising methanogenic activity were used to estimate initial methanogenic biomass concentration and bacterial death rate coefficient. The kinetics of hydrolysis of insoluble fraction could be adequately described by a Contois equation and the kinetics of acidogenesis, and aceticlastic and hydrogen utilising methanogenesis by Monod equations.

  9. Covalent bonds are created by the drive of electron waves to lower their kinetic energy through expansion

    SciTech Connect (OSTI)

    Schmidt, Michael W; Ivanic, Joseph; Ruedenberg, Klaus

    2014-05-28

    An analysis based on the variation principle shows that in the molecules H2 +, H2, B2, C2, N2, O2, F2, covalent bonding is driven by the attenuation of the kinetic energy that results from the delocalization of the electronic wave function. For molecular geometries around the equilibrium distance, two features of the wave function contribute to this delocalization: (i) Superposition of atomic orbitals extends the electronic wave function from one atom to two or more atoms; (ii) intra-atomic contraction of the atomic orbitals further increases the inter-atomic delocalization. The inter-atomic kinetic energy lowering that (perhaps counter-intuitively) is a consequence of the intra-atomic contractions drives these contractions (which per se would increase the energy). Since the contractions necessarily encompass both, the intra-atomic kinetic and potential energy changes (which add to a positive total), the fact that the intra-atomic potential energy change renders the total potential binding energy negative does not alter the fact that it is the kinetic delocalization energy that drives the bond formation.

  10. A reaction-based paradigm to model reactive chemical transport in groundwater with general kinetic and equilibrium reactions

    SciTech Connect (OSTI)

    Zhang, Fan; Yeh, Gour-Tsyh; Parker, Jack C; Brooks, Scott C; Pace, Molly; Kim, Young Jin; Jardine, Philip M; Watson, David B

    2007-01-01

    This paper presents a reaction-based water quality transport model in subsurface flow systems. Transport of chemical species with a variety of chemical and physical processes is mathematically described by M partial differential equations (PDEs). Decomposition via Gauss-Jordan column reduction of the reaction network transforms M species reactive transport equations into two sets of equations: a set of thermodynamic equilibrium equations representing NE equilibrium reactions and a set of reactive transport equations of M-NE kinetic-variables involving no equilibrium reactions (a kinetic-variable is a linear combination of species). The elimination of equilibrium reactions from reactive transport equations allows robust and efficient numerical integration. The model solves the PDEs of kinetic-variables rather than individual chemical species, which reduces the number of reactive transport equations and simplifies the reaction terms in the equations. A variety of numerical methods are investigated for solving the coupled transport and reaction equations. Simulation comparisons with exact solutions were performed to verify numerical accuracy and assess the effectiveness of various numerical strategies to deal with different application circumstances. Two validation examples involving simulations of uranium transport in soil columns are presented to evaluate the ability of the model to simulate reactive transport with complex reaction networks involving both kinetic and equilibrium reactions.

  11. Kinetics of spin relaxation in quantum wires and channels: Boundary spin echo and formation of a persistent spin helix

    SciTech Connect (OSTI)

    Slipko, Valeriy A.; Pershin, Yuriy V.

    2011-10-15

    In this paper we use a spin kinetic equation to study spin-polarization dynamics in one-dimensional (1D) wires and 2D channels. The spin kinetic equation is valid in both diffusive and ballistic spin transport regimes and therefore is more general than the usual spin drift-diffusion equations. In particular, we demonstrate that in infinite 1D wires with Rashba spin-orbit interaction the exponential spin-relaxation decay can be modulated by an oscillating function. In the case of spin relaxation in finite length 1D wires, it is shown that an initially homogeneous spin polarization spontaneously transforms into a persistent spin helix. We find that a propagating spin-polarization profile reflects from a system boundary and returns back to its initial position similarly to the reflectance of sound waves from an obstacle. The Green's function of the spin kinetic equation is derived for both finite and infinite 1D systems. Moreover, we demonstrate explicitly that the spin relaxation in specifically oriented 2D channels with Rashba and Dresselhaus spin-orbit interactions of equal strength occurs similarly to that in 1D wires of finite length. Finally, a simple transformation mapping 1D spin kinetic equation into the Klein-Gordon equation with an imaginary mass is found thus establishing an interesting connection between semiconductor spintronics and relativistic quantum mechanics.

  12. Ion kinetic effects on the ignition and burn of inertial confinement fusion targets: A multi-scale approach

    SciTech Connect (OSTI)

    Peigney, B. E.; Larroche, O.

    2014-12-15

    In this article, we study the hydrodynamics and burn of the thermonuclear fuel in inertial confinement fusion pellets at the ion kinetic level. The analysis is based on a two-velocity-scale Vlasov-Fokker-Planck kinetic model that is specially tailored to treat fusion products (suprathermal α-particles) in a self-consistent manner with the thermal bulk. The model assumes spherical symmetry in configuration space and axial symmetry in velocity space around the mean flow velocity. A typical hot-spot ignition design is considered. Compared with fluid simulations where a multi-group diffusion scheme is applied to model α transport, the full ion-kinetic approach reveals significant non-local effects on the transport of energetic α-particles. This has a direct impact on hydrodynamic spatial profiles during combustion: the hot spot reactivity is reduced, while the inner dense fuel layers are pre-heated by the escaping α-suprathermal particles, which are transported farther out of the hot spot. We show how the kinetic transport enhancement of fusion products leads to a significant reduction of the fusion yield.

  13. Kinetics of Oxygen Surface Exchange on Epitaxial Ruddlesden Popper Phases and Correlations to First-Principles Descriptors

    SciTech Connect (OSTI)

    Lee, Yueh-Lin; Wang, Xiao Renshaw; Lee, Ho Nyung; Morgan, Dane; Yang, Shao-horn

    2016-01-01

    Through alignment of theoretical modeling with experimental measurements of oxygen surface-exchange kinetics on (001)-oriented La2 xSrxMO4+ (M = Co, Ni, Cu) thin films, we demonstrate here the capability of the theoretical bulk O 2p-band centers to correlate with oxygen surface-exchange kinetics of the Ruddlesden Popper oxide (RP214) (001)-oriented thin films. In addition, we demonstrate that the bulk O 2p-band centers can also correlate with the experimental activation energies for bulk oxygen transport and oxygen surface exchange of both the RP214 and the perovskite polycrystalline materials reported in the literature, indicating the effectiveness of the bulk O 2p-band centers in describing the associated energetics and kinetics. We propose that the opposite slopes of the bulk O 2p-band center correlations between the RP214 and the perovskite materials are due to the intrinsic mechanistic differences of their oxygen surface-exchange kinetics bulk anionic transport.

  14. A multiscale variational approach to the kinetics of viscous classical liquids: The coarse-grained mean field approximation

    SciTech Connect (OSTI)

    Sereda, Yuriy V.; Ortoleva, Peter J.

    2014-04-07

    A closed kinetic equation for the single-particle density of a viscous simple liquid is derived using a variational method for the Liouville equation and a coarse-grained mean-field (CGMF) ansatz. The CGMF ansatz is based on the notion that during the characteristic time of deformation a given particle interacts with many others so that it experiences an average interaction. A trial function for the N-particle probability density is constructed using a multiscale perturbation method and the CGMF ansatz is applied to it. The multiscale perturbation scheme is based on the ratio of the average nearest-neighbor atom distance to the total size of the assembly. A constraint on the initial condition is discovered which guarantees that the kinetic equation is mass-conserving and closed in the single-particle density. The kinetic equation has much of the character of the Vlasov equation except that true viscous, and not Landau, damping is accounted for. The theory captures condensation kinetics and takes much of the character of the Gross-Pitaevskii equation in the weak-gradient short-range force limit.

  15. Decay-ratio calculation in the frequency domain with the LAPUR code using 1D-kinetics

    SciTech Connect (OSTI)

    Munoz-Cobo, J. L.; Escriva, A.; Garcia, C.; Berna, C.

    2012-07-01

    This paper deals with the problem of computing the Decay Ratio in the frequency domain codes as the LAPUR code. First, it is explained how to calculate the feedback reactivity in the frequency domain using slab-geometry i.e. 1D kinetics, also we show how to perform the coupling of the 1D kinetics with the thermal-hydraulic part of the LAPUR code in order to obtain the reactivity feedback coefficients for the different channels. In addition, we show how to obtain the reactivity variation in the complex domain by solving the eigenvalue equation in the frequency domain and we compare this result with the reactivity variation obtained in first order perturbation theory using the 1D neutron fluxes of the base case. Because LAPUR works in the linear regime, it is assumed that in general the perturbations are small. There is also a section devoted to the reactivity weighting factors used to couple the reactivity contribution from the different channels to the reactivity of the entire reactor core in point kinetics and 1D kinetics. Finally we analyze the effects of the different approaches on the DR value. (authors)

  16. Neutron emission effects on fragment mass and kinetic energy distribution from fission of 239{sup Pu} induced by thermal neutrons

    SciTech Connect (OSTI)

    Montoya, M.; Rojas, J.; Lobato, I.

    2010-08-04

    The average of fragment kinetic energy (E-bar sign*) and the multiplicity of prompt neutrons ({nu}(bar sign)) as a function of fragment mass (m*), as well as the fragment mass yield (Y(m*)) from thermal neutron-induced fission of {sup 239}Pu have been measured by Tsuchiya et al.. In that work the mass and kinetic energy are calculated from the measured kinetic energy of one fragment and the difference of time of flight of the two complementary fragments. However they do not present their results about the standard deviation {sigma}{sub E}*(m*). In this work we have made a numerical simulation of that experiment which reproduces its results, assuming an initial distribution of the primary fragment kinetic energy (E(A)) with a constant value of the standard deviation as function of fragment mass ({sigma}{sub E}(A)). As a result of the simulation we obtain the dependence {sigma}{sub E}*(m*) which presents an enhancement between m* = 92 and m* = 110, and a peak at m* = 121.

  17. Nonlinear generation of kinetic-scale waves by magnetohydrodynamic Alfvn waves and nonlocal spectral transport in the solar wind

    SciTech Connect (OSTI)

    Zhao, J. S.; Wu, D. J.; Voitenko, Y.; De Keyser, J.

    2014-04-20

    We study the nonlocal nonlinear coupling and generation of kinetic Alfvn waves (KAWs) and kinetic slow waves (KSWs) by magnetohydrodynamic Alfvn waves (MHD AWs) in conditions typical for the solar wind in the inner heliosphere. This cross-scale process provides an alternative to the turbulent energy cascade passing through many intermediate scales. The nonlinearities we study are proportional to the scalar products of wave vectors and hence are called 'scalar' ones. Despite the strong Landau damping of kinetic waves, we found fast growing KAWs and KSWs at perpendicular wavelengths close to the ion gyroradius. Using the parametric decay formalism, we investigate two independent decay channels for the pump AW: forward decay (involving co-propagating product waves) and backward decay (involving counter-propagating product waves). The growth rate of the forward decay is typically 0.05 but can exceed 0.1 of the pump wave frequency. The resulting spectral transport is nonlocal and anisotropic, sharply increasing perpendicular wavenumbers but not parallel ones. AWs and KAWs propagating against the pump AW grow with about the same rate and contribute to the sunward wave flux in the solar wind. Our results suggest that the nonlocal decay of MHD AWs into KAWs and KSWs is a robust mechanism for the cross-scale spectral transport of the wave energy from MHD to dissipative kinetic scales in the solar wind and similar media.

  18. Non-Equilibrium Vibrational Kinetics in Radiofrequency H2 Plasmas: a Comparison Between Theoretical and Experimental Results

    SciTech Connect (OSTI)

    Capitelli, M.; De Pascale, O.; Shakatov, V.; Hassouni, K.; Lombardi, G.; Gicquel, A.

    2005-05-16

    Vibrational and rotational experimental temperatures of molecular hydrogen obtained by Coherent Anti-Stokes Spectroscopy (CARS) in Radiofrequency Inductive Plasmas have been analyzed and interpreted in terms of vibration, electron, dissociation-recombination and attachment kinetics. The analysis clarifies the role of atomic hydrogen and its heterogeneous recombination in affecting the vibrational content of the molecules.

  19. Kinetics of oxygen surface exchange on epitaxial Ruddlesden–Popper phases and correlations to first-principles descriptors

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lee, Yueh -Lin; Wang, Xiao Renshaw; Lee, Ho Nyung; Morgan, Dane; Shao-Horn, Yang; Lee, Dongkyu

    2015-12-17

    Through alignment of theoretical modeling with experimental measurements of oxygen surface-exchange kinetics on (001)-oriented La2–xSrxMO4+δ (M = Co, Ni, Cu) thin films, we demonstrate here the capability of the theoretical bulk O 2p-band centers to correlate with oxygen surface-exchange kinetics of the Ruddlesden–Popper oxide (RP214) (001)-oriented thin films. In addition, we demonstrate that the bulk O 2p-band centers can also correlate with the experimental activation energies for bulk oxygen transport and oxygen surface exchange of both the RP214 and the perovskite polycrystalline materials reported in the literature, indicating the effectiveness of the bulk O 2p-band centers in describing the associatedmore » energetics and kinetics. Here, we propose that the opposite slopes of the bulk O 2p-band center correlations between the RP214 and the perovskite materials are due to the intrinsic mechanistic differences of their oxygen surface-exchange kinetics bulk anionic transport.« less

  20. ROLES OF THE KINETIC AND DYNAMIC MECHANISMS IN THE L{sub p} -E{sub p} RELATION

    SciTech Connect (OSTI)

    Qin, Yi-Ping; Chen, Zhi-Fu

    2013-04-10

    The L{sub p} -E{sub p} relation is a well-known relation in gamma-ray bursts (GRBs). Its implication remains unclear. We propose to investigate the underlying mechanisms of this relation by considering the corresponding kinetic and dynamic mechanisms separately. In this way, one can tell how much the kinetic or dynamic mechanism contributes to the index of the relationship. Our analysis gives rise to several conclusions. (1) The index of the kinetic effect in the L{sub p} -E{sub p} relation can simply be derived from the theory of special relativity, which is generally larger than 2, depending on the situation concerned. (2) The index of the dynamic effect in the relation can be deduced from observation once a model of jets is adopted. According to current GRB data, we find that the dynamic effect alone tends to give rise to an anti-correlation between L{sub p} and E{sub p} ; in terms of statistics, the dynamic effect is obviously smaller than the kinetic effect; in the situation of jets with moving discrete radio clouds that move directly toward the observer, the index of the dynamic effect is currently constrained within (- 1.6, -1), while in other situations of jets, the constraints are different; both internal and external shocks can account for the current data.