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1

Blowoff dynamics of bluff body stabilized turbulent premixed flames  

SciTech Connect (OSTI)

This article concerns the flame dynamics of a bluff body stabilized turbulent premixed flame as it approaches lean blowoff. Time resolved chemiluminescence imaging along with simultaneous particle image velocimetry and OH planar laser-induced fluorescence were utilized in an axisymmetric bluff body stabilized, propane-air flame to determine the sequence of events leading to blowoff and provide a quantitative analysis of the experimental results. It was found that as lean blowoff is approached by reduction of equivalence ratio, flame speed decreases and the flame shape progressively changes from a conical to a columnar shape. For a stably burning conical flame away from blowoff, the flame front envelopes the shear layer vortices. Near blowoff, the columnar flame front and shear layer vortices overlap to induce high local stretch rates that exceed the extinction stretch rates instantaneously and in the mean, resulting in local flame extinction along the shear layers. Following shear layer extinction, fresh reactants can pass through the shear layers to react within the recirculation zone with all other parts of the flame extinguished. This flame kernel within the recirculation zone may survive for a few milliseconds and can reignite the shear layers such that the entire flame is reestablished for a short period. This extinction and reignition event can happen several times before final blowoff which occurs when the flame kernel fails to reignite the shear layers and ultimately leads to total flame extinguishment. (author)

Chaudhuri, Swetaprovo; Kostka, Stanislav; Renfro, Michael W.; Cetegen, Baki M. [Department of Mechanical Engineering, University of Connecticut, 191 Auditorium Road, U-3139, Storrs, CT 06269 (United States)

2010-04-15T23:59:59.000Z

2

Numerical studies of flames in wide tubes:?Stability limits of curved stationary flames  

Science Journals Connector (OSTI)

Flame dynamics in wide tubes with ideally adiabatical and slip walls is studied by means of direct numerical simulations of the complete set of hydrodynamical equations including thermal conduction, fuel diffusion, viscosity, and chemical kinetics. Stability limits of curved stationary flames in wide tubes and the hydrodynamic instability of these flames (the secondary Darrieus-Landau instability) are investigated. The stability limits found in the present numerical simulations are in a very good agreement with the previous theoretical predictions. It is obtained that close to the stability limits the secondary Darrieus-Landau instability results in an extra cusp at the flame front. It is shown that the curved flames subject to the secondary Darrieus-Landau instability propagate with velocity considerably larger than the velocity of the stationary flames.

O. Yu. Travnikov; V. V. Bychkov; M. A. Liberman

2000-01-01T23:59:59.000Z

3

Stability Regimes of Turbulent Nitrogen-Diluted Hydrogen Jet Flames  

SciTech Connect (OSTI)

One option for combustion in zero-emission Integrated Gasification Combined Cycle (IGCC) power plants is non-premixed combustion of nitrogen-diluted hydrogen in air. An important aspect to non-premixed combustion is flame stability or anchoring, though only a few fundamental stability studies of these flames have taken place to date. The following paper presents the results of experiments investigating the effects of nitrogen diluent fraction, jet diameter, and exit velocity on the static stability limits of a turbulent hydrogen jet flame issuing from a thin-lipped tube into a quiescent atmosphere. Four different stability limits are observed: detachment from the burner lip, reattachment to the burner lip, transition from a laminar lifted flame base to blowout or to a turbulent lifted flame, and transition from a turbulent lifted flame to blowout. The applicability of existing theories and correlations to the stability results is discussed. These results are an important step in assessing the viability of a non-premixed combustion approach using hydrogen diluted with nitrogen as a fuel.

Weiland, N.T.; Strakey, P.A.

2007-03-01T23:59:59.000Z

4

A DNS study on the stabilization mechanism of a turbulent lifted ethylene jet flame in highly-heated coflow  

SciTech Connect (OSTI)

Direct numerical simulation (DNS) of the near-field of a three-dimensional spatially-developing turbulent ethylene jet flame in highly-heated coflow is performed with a reduced mechanism to determine the stabilization mechanism. The DNS was performed at a jet Reynolds number of 10,000 with over 1.29 billion grid points. The results show that auto-ignition in a fuel-lean mixture at the flame base is the main source of stabilization of the lifted jet flame. The Damkoehler number and chemical explosive mode (CEM) analysis also verify that auto-ignition occurs at the flame base. In addition to auto-ignition, Lagrangian tracking of the flame base reveals the passage of large-scale flow structures and their correlation with the fluctuations of the flame base similar to a previous study (Yoo et al., J. Fluid Mech. 640 (2009) 453-481) with hydrogen/air jet flames. It is also observed that the present lifted flame base exhibits a cyclic 'saw-tooth' shaped movement marked by rapid movement upstream and slower movement downstream. This is a consequence of the lifted flame being stabilized by a balance between consecutive auto-ignition events in hot fuel-lean mixtures and convection induced by the high-speed jet and coflow velocities. This is confirmed by Lagrangian tracking of key variables including the flame-normal velocity, displacement speed, scalar dissipation rate, and mixture fraction at the stabilization point.

Yoo, Chun S [Sandia National Laboratories (SNL)

2011-01-01T23:59:59.000Z

5

Syngas production from burner-stabilized methane/air flames: The effect of preheated reactants  

Science Journals Connector (OSTI)

The effect of preheated reactants on syngas production from a methane/air flame was investigated over a range of inlet temperatures up to 630 K. In addition to experimental measurements, the results from a burner-stabilized flame and freely-propagating flame models are presented. A comparison of the modeling and experimental results in terms of flame standoff distance, stability limit conditions and species yields show excellent agreement across a broad range of equivalence ratios and preheat temperatures. Preheating of reactants increased the rich limit for stable operation from 1.26 to 1.75 for a given inlet velocity, and syngas yields were shown to increase with equivalence ratio. The preheat temperature of the reactants was shown to have little impact on syngas yields beyond extending the limits of stable operation. The results of this study are useful for the design and analysis of heat recirculating reactors and other reactors that are designed for producing syngas through the combustion of rich mixtures.

Colin H. Smith; Daniel I. Pineda; Janet L. Ellzey

2013-01-01T23:59:59.000Z

6

Stability characteristics of non-premixed turbulent jet flames of hydrogen and syngas blends with coaxial air  

Science Journals Connector (OSTI)

The stability characteristics of attached hydrogen (H2) and syngas (H2/CO) turbulent jet flames with coaxial air were studied experimentally. The flame stability was investigated by varying the fuel and air stream velocities. Effects of the coaxial nozzle diameter, fuel nozzle lip thickness and syngas fuel composition are addressed in detail. The detachment stability limit of the syngas single jet flame was found to decrease with increasing amount of carbon monoxide in the fuel. For jet flames with coaxial air, the critical coaxial air velocity leading to flame detachment first increases with increasing fuel jet velocity and subsequently decreases. This non-monotonic trend appears for all syngas composition herein investigated (50/50 ? 100/0% H2/CO). OH? chemiluminescence imaging was performed to qualitatively identify the mechanisms responsible for the flame detachment. For all fuel compositions, local extinction close to the burner rim is observed at lower fuel velocities (ascending stability limit), while local flame extinction downstream of the burner rim is observed at higher fuel velocities (descending stability limit). Extrema of the non-monotonic trends appear to be identical when the nozzle fuel velocity is normalized by the critical fuel velocity obtained for the single jet cases.

Jeongjae Hwang; Nicolas Bouvet; Kitae Sohn; Youngbin Yoon

2013-01-01T23:59:59.000Z

7

Flame Stability of Methane and Syngas Oxy-fuel Steam Flames  

Science Journals Connector (OSTI)

The scaling relation [gF = c(SL2/?)] for different burner diameters was obtained for various diameter burners. ... The fuels used for these experiments were methane and syngas (CO–H2), which were burned with oxidants O2 and recirculated CO2 and H2O. Research-grade fuel and oxidant were delivered to the burners from pressurized tanks. ... Narrower flammable regimes and lower laminar burning velocity under oxy-fuel combustion conditions may lead to new stability challenges in operating oxy-coal burners. ...

B. K. Dam; N. D. Love; A. R. Choudhuri

2012-11-26T23:59:59.000Z

8

Effect of Blending on High-Pressure Laminar Flame Speed Measurements, Markstein Lengths, and Flame Stability of Hydrocarbons  

E-Print Network [OSTI]

, 5, and 10 .................................................. 40 Figure 26 Pure CH3OCH3 results for initial pressures of 1, 5, and 10 atm ................................................ 41 Figure 27 Flame speed results for 80/20 CH4/C2H6... .............................................................................................. 44 Figure 30 Flame speed results for 80/20 CH4/CH3OCH3 at initial pressures of 1, 5, and 10 atm compared to modeled results .................................................................................. 45 Figure 31 Flame speed results...

Lowry, William Baugh

2012-02-14T23:59:59.000Z

9

Flame-Retardant Epoxy Resin Nanocomposites Reinforced with Polyaniline-Stabilized Silica Nanoparticles  

E-Print Network [OSTI]

, Henry A. Colorado, Suying Wei,*,# and Zhanhu Guo*, Integrated Composites Lab (ICL), Dan F. Smith silsesquioxanes (POSS) reinforced epoxy composites.10 For the third method, the inorganic nanoparticles are often (ATH),13 silica (SiO2),14 nanoclay,15 and newly developed phosphorus- containing flame retardants 9

Guo, John Zhanhu

10

Dynamics and structure of stretched flames  

SciTech Connect (OSTI)

This program aims to gain fundamental understanding on the structure, geometry, and dynamics of laminar premixed flames, and relate these understanding to the practical issues of flame extinction and stabilization. The underlying fundamental interest here is the recent recognition that the response of premixed flames can be profoundly affected by flame stretch, as manifested by flow nonuniformity, flame curvature, and flame/flow unsteadiness. As such, many of the existing understanding on the behavior of premixed flames need to be qualitatively revised. The research program consists of three major thrusts: (1) detailed experimental and computational mapping of the structure of aerodynamically-strained planar flames, with emphasis on the effects of heat loss, nonequidiffusion, and finite residence time on the flame thickness, extent of incomplete reaction, and the state of extinction. (2) Analytical study of the geometry and dynamics of stretch-affected wrinkled flame sheets in simple configurations, as exemplified by the Bunsen flame and the spatially-periodic flame, with emphasis on the effects of nonlinear stretch, the phenomena of flame cusping, smoothing, and tip opening, and their implications on the structure and burning rate of turbulent flames. (3) Stabilization and blowoff of two-dimensional inverted premixed and stabilization and determining the criteria governing flame blowoff. The research is synergistically conducted through the use of laser-based diagnostics, computational simulation of the flame structure with detailed chemistry and transport, and mathematical analysis of the flame dynamics.

Law, C.K. [Princeton Univ., NJ (United States)

1993-12-01T23:59:59.000Z

11

1 Copyright 2007 by ASME Flame Structure and Stabilization Mechanisms in a  

E-Print Network [OSTI]

natural gas and air at atmospheric pressure. These include simultaneous Planar Laser-Induced Fluorescence and exhaust gas recirculation. Preheating the combustion air with the exhaust gases from a combustor provides. In most premixed combustors employed in land-based gas turbines, stabilization is partially achieved

Seitzman, Jerry M.

12

Flame Chemistry and Diagnostics  

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

Details Photoionization Mass Spectrometer Flame Conditions Flame Chemistry Insights (n-butanol flame) Experiment vs. Model Fuel-Consumption Pathways...

13

Large eddy simulation/conditional moment closure modeling of swirl-stabilized non-premixed flames with local extinction  

E-Print Network [OSTI]

, L. Vervisch, P. Domingo, Combust. Flame 146 (2006), 635-648. 28. S. Navarro-Martinez, A. Kronenburg, F.D. Mare, Flow Turbul. Combust. 75 (2005), 245-274. 29. A. Triantafyllidis, E. Mastorakos, Flow Turbul. Combust. 84 (2010), 481-512. 30. M...

Zhang, Huangwei; Garmory, Andrew; Cavaliere, Davide E.; Mastorakos, Epaminondas

2014-06-25T23:59:59.000Z

14

Using Ligand-Based Virtual Screening to Allosterically Stabilize the Activated State of a  

E-Print Network [OSTI]

to the intra- cellular loops. A short tetrazole peptidomimetic based on the photoactivated state of rhodopsin from the designed tetrazole tetra- peptide was used for ligand-based virtual screen- ing to enhance

Marshall, Garland R.

15

Characterisation of an oxy-coal flame through digital imaging  

SciTech Connect (OSTI)

This paper presents investigations into the impact of oxy-fuel combustion on flame characteristics through the application of digital imaging and image processing techniques. The characteristic parameters of the flame are derived from flame images that are captured using a vision-based flame monitoring system. Experiments were carried out on a 0.5 MW{sub th} coal combustion test facility. Different flue gas recycle ratios and furnace oxygen levels were created for two different coals. The characteristics of the flame and the correlation between the measured flame parameters and corresponding combustion conditions are described and discussed. The results show that the flame temperature decreases with the recycle ratio for both test coals, suggesting that the flame temperature is effectively controlled by the flue gas recycle ratio. The presence of high levels of CO{sub 2} at high flue gas recycle ratios may result in delayed combustion and thus has a detrimental effect on the flame stability. (author)

Smart, John; Riley, Gerry [RWE npower plc, Windmill Hill Business Park, Whitehill Way, Swindon SN5 6PB (United Kingdom); Lu, Gang; Yan, Yong [Instrumentation, Control and Embedded Systems Research Group, School of Engineering and Digital Arts, University of Kent, Canterbury, Kent CT2 7NT (United Kingdom)

2010-06-15T23:59:59.000Z

16

Investigations of swirl flames in a gas turbine model combustor  

SciTech Connect (OSTI)

The thermochemical states of three swirling CH{sub 4}/air diffusion flames, stabilized in a gas turbine model combustor, were investigated using laser Raman scattering. The flames were operated at different thermal powers and air/fuel ratios and exhibited different flame behavior with respect to flame instabilities. They had previously been characterized with respect to their flame structures, velocity fields, and mean values of temperature, major species concentrations, and mixture fraction. The single-pulse multispecies measurements presented in this article revealed very rapid mixing of fuel and air, accompanied by strong effects of turbulence-chemistry interactions in the form of local flame extinction and ignition delay. Flame stabilization is accomplished mainly by hot and relatively fuel-rich combustion products, which are transported back to the flame root within an inner recirculation zone. The flames are not attached to the fuel nozzle, and are stabilized approximately 10 mm above the fuel nozzle, where fuel and air are partially premixed before ignition. The mixing and reaction progress in this area are discussed in detail. The flames are short (<50 mm), especially that exhibiting thermoacoustic oscillations, and reach a thermochemical state close to adiabatic equilibrium at the flame tip. The main goals of this article are to outline results that yield deeper insight into the combustion of gas turbine flames and to establish an experimental database for the validation of numerical models.

Meier, W.; Duan, X.R.; Weigand, P. [Institut fuer Verbrennungstechnik, Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), Pfaffenwaldring 38, D-70569 Stuttgart (Germany)

2006-01-01T23:59:59.000Z

17

On the Stability of Thermonuclear Burning Fronts in Type Ia Supernovae  

Science Journals Connector (OSTI)

The propagation of cellularly stabilized thermonuclear flames is investigated by means of numerical ... fuel flows. Our simulations indicate that in thermonuclear supernova explosions stable cellular flames devel...

F.K. Röpke; W. Hillebrandt

2005-01-01T23:59:59.000Z

18

LES/probability density function approach for the simulation of an ethanol spray flame  

E-Print Network [OSTI]

LES/probability density function approach for the simulation of an ethanol spray flame Colin Heye a an experimental pilot-stabilized ethanol spray flame. In this particular flame, droplet evaporation occurs away: Large-eddy simulation; Probability density function; Flamelet/progress variable approach; Ethanol

Raman, Venkat

19

E-Print Network 3.0 - advanced flame quality Sample Search Results  

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

paper overviews the dynamics of bluff body... stabilized flames and describes the phenomenology of the blowoff process. The first section of the paper Source: Lieuwen, Timothy C....

20

NO concentration imaging in turbulent nonpremixed flames  

SciTech Connect (OSTI)

The importance of NO as a pollutant species is well known. An understanding of the formation characteristics of NO in turbulent hydrocarbon flames is important to both the desired reduction of pollutant emissions and the validation of proposed models for turbulent reacting flows. Of particular interest is the relationship between NO formation and the local flame zone, in which the fuel is oxidized and primary heat release occurs. Planar imaging of NO provides the multipoint statistics needed to relate NO formation to the both the flame zone and the local turbulence characteristics. Planar imaging of NO has been demonstrated in turbulent flames where NO was seeded into the flow at high concentrations (2000 ppm) to determine the gas temperature distribution. The NO concentrations in these experiments were significantly higher than those expected in typical hydrocarbon-air flames, which require a much lower detectability limit for NO measurements. An imaging technique based on laser-induced fluorescence with sufficient sensitivity to study the NO formation mechanism in the stabilization region of turbulent lifted-jet methane flames.

Schefer, R.W. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Flame front geometry in premixed turbulent flames  

SciTech Connect (OSTI)

Experimental and numerical determinations of flame front curvature and orientation in premixed turbulent flames are presented. The experimental data is obtained from planar, cross sectional images of stagnation point flames at high Damkoehler number. A direct numerical simulation of a constant energy flow is combined with a zero-thickness, constant density flame model to provide the numerical results. The computational domain is a 32{sup 3} cube with periodic boundary conditions. The two-dimensional curvature distributions of the experiments and numerical simulations compare well at similar q{prime}/S{sub L} values with means close to zero and marked negative skewness. At higher turbulence levels the simulations show that the distributions become symmetric about zero. These features are also found in the three dimensional distributions of curvature. The simulations support assumptions which make it possible to determine the mean direction cosines from the experimental data. This leads to a reduction of 12% in the estimated flame surface area density in the middle of the flame brush. 18 refs.

Shepherd, I.G. (Lawrence Berkeley Lab., CA (United States)); Ashurst, W.T. (Sandia National Labs., Livermore, CA (United States))

1991-12-01T23:59:59.000Z

22

The effect of fuel composition on flame dynamics  

SciTech Connect (OSTI)

As fuel sources diversify, the gas turbine industry is under increasing pressure to develop fuel-flexible plants, able to use fuels with a variety of compositions from a large range of sources. However, the dynamic characteristics vary considerably with composition, in many cases altering the thermoacoustic stability of the combustor. We compare the flame dynamics, or the response in heat release rate of the flame to acoustic perturbations, of the three major constituents of natural gas: methane, ethane, and propane. The heat release rate is quantified using OH* chemiluminescence and product gas temperature. Gas temperature is measured by tracking the absorption of two high-temperature water lines, via Tunable Diode Laser Absorption Spectroscopy. The flame dynamics of the three fuels differ significantly. The changes in flame dynamics due to variations in fuel composition have the potential to have a large effect on the thermoacoustic stability of the combustor. (author)

Hendricks, Adam G.; Vandsburger, Uri [Department of Mechanical Engineering - 0238, Virginia Tech, Blacksburg, VA 24061 (United States)

2007-10-15T23:59:59.000Z

23

Kinetic effects of non-equilibrium plasma-assisted methane oxidation on diffusion flame extinction limits  

E-Print Network [OSTI]

. The prod- ucts of plasma assisted CH4 oxidation were measured using the Two-photon Absorption Laser to understand the role of plasma generated species on ignition, flame speed, and flame stabilization. For ignition studies, the reduction of ignition delay time by non-equilibrium nanosecond pulsed discharges

Ju, Yiguang

24

Flame propagation enhancement by plasma excitation of oxygen. Part I: Effects of O{sub 3}  

SciTech Connect (OSTI)

The thermal and kinetic effects of O{sub 3} on flame propagation were investigated experimentally and numerically by using C{sub 3}H{sub 8}/O{sub 2}/N{sub 2} laminar lifted flames. Ozone produced by a dielectric barrier plasma discharge was isolated and measured quantitatively by using absorption spectroscopy. Significant kinetic enhancement by O{sub 3} was observed by comparing flame stabilization locations with and without O{sub 3} production. Experiments at atmospheric pressures showed an 8% enhancement in the flame propagation speed for 1260 ppm of O{sub 3} addition to the O{sub 2}/N{sub 2} oxidizer. Numerical simulations showed that the O{sub 3} decomposition and reaction with H early in the pre-heat zone of the flame produced O and OH, respectively, from which the O reacted rapidly with C{sub 3}H{sub 8} and produced additional OH. The subsequent reaction of OH with the fuel and fuel fragments, such as CH{sub 2}O, provided chemical heat release at lower temperatures to enhance the flame propagation speed. It was shown that the kinetic effect on flame propagation enhancement by O{sub 3} reaching the pre-heat zone of the flame for early oxidation of fuel was much greater than that by the thermal effect from the energy contained within O{sub 3}. For non-premixed laminar lifted flames, the kinetic enhancement by O{sub 3} also induced changes to the hydrodynamics at the flame front which provided additional enhancement of the flame propagation speed. The present results will have a direct impact on the development of detailed plasma-flame kinetic mechanisms and provided a foundation for the study of combustion enhancement by O{sub 2}(a{sup 1}{delta}{sub g}) in part II of this investigation. (author)

Ombrello, Timothy; Won, Sang Hee; Ju, Yiguang [Department of Mechanical and Aerospace Engineering, Engineering Quadrangle, Olden Street, Princeton, NJ 08544 (United States); Williams, Skip [Air Force Research Laboratory, Propulsion Directorate, 1950 Fifth Street, Wright-Patterson AFB, OH 45433 (United States)

2010-10-15T23:59:59.000Z

25

Dynamics of premixed flames in a narrow channel with a step-wise wall temperature  

SciTech Connect (OSTI)

The effect of channel height, inflow velocity and wall temperature on the dynamics and stability of unity Lewis number premixed flames in channels with specified wall temperature is investigated with steady and transient numerical simulations using a two-dimensional thermo-diffusive model. The simplified model is capable of capturing many of the transitions and the combustion modes observed experimentally and in direct numerical simulations in micro- and meso-scale channels, and indicates that the thermal flame/wall interaction is the mechanism leading to the observed flame instabilities. Finally, an ad-hoc one-dimensional model based on the flame-sheet approximation is tested in its capacity to reproduce some of the flame dynamics of the two-dimensional thermo-diffusive model. (author)

Kurdyumov, Vadim N. [Department of Energy, CIEMAT, Avda. Complutense 22, 28040 Madrid (Spain); Pizza, Gianmarco [Aerothermochemistry and Combustion Systems Laboratory, Swiss Federal Institute of Technology, Zurich CH-8092 (Switzerland); Combustion Research, Paul Scherrer Institute, Villigen CH-5232 (Switzerland); Frouzakis, Christos E. [Aerothermochemistry and Combustion Systems Laboratory, Swiss Federal Institute of Technology, Zurich CH-8092 (Switzerland); Mantzaras, John [Combustion Research, Paul Scherrer Institute, Villigen CH-5232 (Switzerland)

2009-11-15T23:59:59.000Z

26

Investigation of the nonlinear response of turbulent premixed flames to imposed inlet velocity oscillations  

SciTech Connect (OSTI)

Acoustically forced lean premixed turbulent bluff-body stabilized flames are investigated using turbulent combustion CFD. The calculations simulate aspects of the experimental investigation by Balachandran et al. [R. Balachandran, B. Ayoola, C. Kaminski, A. Dowling, E. Mastorakos, Combust. Flame 143 (2005) 37-55] and focus on the amplitude dependence of the flame response. For the frequencies of interest in this investigation an unsteady Reynolds-averaged Navier-Stokes (URANS) approach is appropriate. The combustion is represented using a modified laminar flamelet approach with an algebraic representation of the flame surface density. The predictions are compared with flame surface density (FSD) and OH* chemiluminescence measurements. In the experiments the response of the flame has been quantified by means of a number of single-frequency, amplitude-dependent transfer functions. The predicted flame shape and position are in good agreement with the experiment. The dynamic response of the flame to inlet velocity forcing is also well captured by the calculations. At moderate frequencies nonlinear behavior of the transfer functions is observed as the forcing amplitude is increased. In the experiments this nonlinearity was attributed in part to the rollup of the reacting shear layer into vortices and in part to the collision of the inner and outer flame sheets. This transition to nonlinearity is also observed in the transfer functions obtained from the predictions. Furthermore, the vortex shedding and flame-sheet collapse may be seen in snapshots of the predicted flow field taken throughout the forcing cycle. The URANS methodology successfully predicts the behavior of the forced premixed turbulent flames and captures the effects of saturation in the transfer function of the response of the heat release to velocity fluctuations. (author)

Armitage, C.A.; Mastorakos, E.; Cant, R.S. [Department of Engineering, Trumpington Street, University of Cambridge, Cambridge, CB2 1PZ (United Kingdom); Balachandran, R. [Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom)

2006-08-15T23:59:59.000Z

27

Flame front structure of turbulent premixed flames of syngas oxyfuel mixtures  

Science Journals Connector (OSTI)

Abstract In order to investigate oxyfuel combustion characteristics of typical composition of coal gasification syngas connected to CCS systems. Instantaneous flame front structure of turbulent premixed flames of CO/H2/O2/CO2 mixtures which represent syngas oxyfuel combustion was quantitatively studied comparing with CH4/air and syngas/air flames by using a nozzle-type Bunsen burner. Hot-wire anemometer and OH-PLIF were used to measure the turbulent flow and detect the instantaneous flame front structure, respectively. Image processing and statistical analyzing were performed using the Matlab Software. Flame surface density, mean progress variable, local curvature radius, mean flame volume, and flame thickness, were obtained. Results show that turbulent premixed flames of syngas possess wrinkled flame front structure which is a general feature of turbulent premixed flames. Flame surface density for the CO/H2/O2/CO2 flame is much larger than that of CO/H2/O2/air and CH4/air flames. This is mainly caused by the smaller flame intrinsic instability scale, which would lead to smaller scales and less flame passivity response to turbulence presented by Markstain length, which reduce the local flame stretch against turbulence vortex. Peak value of Possibility Density Function (PDF) distribution of local curvature radius, R, for CO/H2/O2/CO2 flames is larger than those of CO/H2/O2/air and CH4/air flames at both positive and negative side and the corresponding R of absolute peak PDF is the smallest. This demonstrates that the most frequent scale is the smallest for CO/H2/O2/CO2 flames. Mean flame volume of CO/H2/O2/CO2 flame is smaller than that of CH4/air flame even smaller than that of CO/H2/O2/air flame. This would be due to the lower flame height and smaller flame wrinkles.

Meng Zhang; Jinhua Wang; Jin Wu; Zhilong Wei; Zuohua Huang; Hideaki Kobayashi

2014-01-01T23:59:59.000Z

28

Direct numerical simulations of type Ia supernovae flames I: The landau-darrieus instability  

SciTech Connect (OSTI)

Planar flames are intrinsically unstable in open domains due to the thermal expansion across the burning front--the Landau-Darrieus instability. This instability leads to wrinkling and growth of the flame surface, and corresponding acceleration of the flame, until it is stabilized by cusp formation. We look at the Landau-Darrieus in stability for C/O thermonuclear flames at conditions relevant to the late stages of a Type Ia supernova explosion. Two-dimensional direct numerical simulations of both single-mode and multi-mode perturbations using a low Mach number hydrodynamics code are presented. We show the effect of the instability on the flame speed as a function of both the density and domain size, demonstrate the existence of the small scale cutoff to the growth of the instability, and look for the proposed breakdown of the non-linear stabilization at low densities. The effects of curvature on the flame as quantified through measurements of the growth rate and computation of the corresponding Markstein number. While accelerations of a few percent are observed, they are too small to have any direct outcome on the supernova explosion.

Bell, J.B.; Day, M.S.; Rendleman, C.A.; Woosley, S.E.; Zingale, M.

2003-11-24T23:59:59.000Z

29

Cal Flame: Order (2015-CE-14015)  

Broader source: Energy.gov [DOE]

DOE ordered Cal Flame to pay a $8,000 civil penalty after finding Cal Flame had failed to certify that refrigerator basic model BBQ09849P-H complies with the applicable energy conservation standards.

30

Production Of Fullerenic Soot In Flames  

DOE Patents [OSTI]

A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

Howard, Jack B. (Winchester, MA); Vander Sande, John B. (Newbury, MA); Chowdhury, K. Das (Cambridge, MA)

2000-12-19T23:59:59.000Z

31

Production of fullerenic nanostructures in flames  

DOE Patents [OSTI]

A method for the production of fullerenic nanostructures is described in which unsaturated hydrocarbon fuel and oxygen are combusted in a burner chamber at a sub-atmospheric pressure, thereby establishing a flame. The condensibles of the flame are collected at a post-flame location. The condensibles contain fullerenic nanostructures, such as single and nested nanotubes, single and nested nanoparticles and giant fullerenes. The method of producing fullerenic soot from flames is also described.

Howard, Jack B. (Winchester, MA); Vander Sande, John B. (Newbury, MA); Chowdhury, K. Das (Cambridge, MA)

1999-01-01T23:59:59.000Z

32

Premixed-gas flames Paul D. Ronney  

E-Print Network [OSTI]

Premixed-gas flames Paul D. Ronney Department of Aerospace and Mechanical Engineering University of Southern California, Los Angeles, CA 90089-1453 USA ronney@usc.edu Keywords: Microgravity; premixed-gas; cool flames; turbulence. Reference: Ronney, P. D., "Premixed-Gas Flames," in: Microgravity Combustion

33

On the Stability of Thermonuclear Burning Fronts in Type Ia Supernovae  

E-Print Network [OSTI]

The propagation of cellularly stabilized thermonuclear flames is investigated by means of numerical simulations. In Type Ia supernova explosions the corresponding burning regime establishes at scales below the Gibson length. The cellular flame stabilization - which is a result of an interplay between the Landau-Darrieus instability and a nonlinear stabilization mechanism - is studied for the case of propagation into quiescent fuel as well as interaction with vortical fuel flows. Our simulations indicate that in thermonuclear supernova explosions stable cellular flames develop around the Gibson scale and that deflagration-to-detonation transition is unlikely to be triggered from flame evolution effects here.

F. K. Roepke; W. Hillebrandt

2004-04-26T23:59:59.000Z

34

Autoignited laminar lifted flames of propane in coflow jets with tribrachial edge and mild combustion  

SciTech Connect (OSTI)

Characteristics of laminar lifted flames have been investigated experimentally by varying the initial temperature of coflow air over 800 K in the non-premixed jets of propane diluted with nitrogen. The result showed that the lifted flame with the initial temperature below 860 K maintained the typical tribrachial structure at the leading edge, which was stabilized by the balance mechanism between the propagation speed of tribrachial flame and the local flow velocity. For the temperature above 860 K, the flame was autoignited without having any external ignition source. The autoignited lifted flames were categorized in two regimes. In the case with tribrachial edge structure, the liftoff height increased nonlinearly with jet velocity. Especially, for the critical condition near blowout, the lifted flame showed a repetitive behavior of extinction and reignition. In such a case, the autoignition was controlled by the non-adiabatic ignition delay time considering heat loss such that the autoignition height was correlated with the square of the adiabatic ignition delay time. In the case with mild combustion regime at excessively diluted conditions, the liftoff height increased linearly with jet velocity and was correlated well with the square of the adiabatic ignition delay time. (author)

Choi, B.C.; Kim, K.N.; Chung, S.H. [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-744 (Korea)

2009-02-15T23:59:59.000Z

35

Clothes That Care -- Flame Resistant Protection.  

E-Print Network [OSTI]

.. 8-1272 othes That Care- Flame Resistant Protection" TOoe ZTA245.7 8873 NQ.'2'T2 Texas Agricultural Extension Service . The Texas A&M University System Daniel C. Pfannstiel, Director, College Station, Texas , ? Clothes That Care- Flame... Resistant Protection Claudia Kerbel * Concern for a safer environment has led to changes in many of the everyday products we use , including clothing . In the' past dec ade, flame-resistant (FR) garments and fabrics have become more available than ever...

Kerbel, Claudia

1980-01-01T23:59:59.000Z

36

Virtual Classroom | Department of Energy  

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

Virtual Classroom Virtual Classroom Adobe Connect is as web conferencing tool that is being used as a virtual classroom in an ongoing pilot to conduct virtual Instructor Led...

37

High-Pressure Flame Speed Measurements  

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

addition on flame speeds of hydrocarbon fuels 3. Soot formation and explosive gasification in burning droplets of dieselbiodieselethanol blends C. K. Law Princeton...

38

Flame retardant finishing of cotton fleece.  

E-Print Network [OSTI]

??In this research, an inorganic phosphorus-containing flame retardant system was developed for cotton fleece. The aluminum hydroxyphosphate (AHP) formed in situ on cotton by the… (more)

Wu, Xialing

2008-01-01T23:59:59.000Z

39

Fuel effects on flame lift-off under diesel conditions  

SciTech Connect (OSTI)

An apparent relation between the lift-off length under diesel conditions and the ignition quality of a fuel has previously been reported. To cast light on the underlying mechanism, the current study aims to separate flame lift-off effects of the chemical ignition delay from those of other fuel properties under diesel conditions. Flame lift-off was measured in an optical diesel engine by high-speed video imaging of OH-chemiluminescence. Fuel and ambient-gas properties were varied during the experiment. Only a weak correlation was found between ignition delay and lift-off length. The data indicate that this correlation is due to a common, stronger correlation with the ambient oxygen concentration. The chemical ignition delay and the fuel type had similar, weak effects on the lift-off length. A recently proposed mechanism for lift-off stabilization was used to interpret the results. It assumes that reactants approaching the lift-off position of the jet are mixed with high-temperature products found along the edges of the flame, which trigger autoignition. In this picture, the fuel effect is most likely due to differences in the amount of mixing with high-temperature products that is required for autoignition. In the current experiment, all lift-off effects seem to arise from variations in the reactant and product temperatures, induced by fuel and ambient properties. (author)

Persson, Helena; Andersson, Oeivind; Egnell, Rolf [Lund University (Sweden). Dept. of Energy Sciences

2011-01-15T23:59:59.000Z

40

Virtual impactor  

DOE Patents [OSTI]

A virtual impactor is described having improved efficiency and low wall losses in which a core of clean air is inserted into the aerosol flow while aerosol flow is maintained adjacent to the inner wall surfaces of the focusing portion of the impactor. The flow rate of the core and the length of the throat of the impactor's collection probe, as well as the dimensional relationships of other components of the impactor adjacent the separation region of the impactor, are selected to optimize separation efficiency. 4 figs.

Yeh, H.C.; Chen, B.T.; Cheng, Y.S.; Newton, G.J.

1988-08-30T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

The Cool Flame Combustion of Ethanol  

Science Journals Connector (OSTI)

...research-article The Cool Flame Combustion of Ethanol J. Brown C. F. H. Tipper The kinetics...products of the cool flame combustion of ethanol between about 280 and 330 C have been...much less for a 1 : 2 than for a 1 : 1 ethanol/oxygen mixture at constant T and varied...

1969-01-01T23:59:59.000Z

42

A Hydrogen Singing-Flame Ionization Detector  

Science Journals Connector (OSTI)

......occurs un- der certain hydrogen, air, and sam- ple...which was the fact that methods of increas- ing ion...inverted glass jar over a hydrogen diffusion flame to demonstrate...optimum in the normal hydrogen diffusion flame and...reasons for the higher ion production. Advantages of the......

L. B. Graiff

1965-05-01T23:59:59.000Z

43

Polymer combustion: effects of flame emissivity  

Science Journals Connector (OSTI)

...gas phase. Polymer combustion chemistry is modelled...investigating polymer combustion it has proven advantageous...properties and treat the heat flux from the ignition...luminous flames from hydrocarbon fuels, it is common...A (1999) Polymer combustion: effects of flame emissivity...

1999-01-01T23:59:59.000Z

44

Virtual Prairie  

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

Visualizing a Real Prairie: Visualizing a Real Prairie: Tools to Represent Your Data Site Index for ( Quadrat Study Project - Prairie Advocates Project - Online Prairie Data) You may use the virtual prairies you create in your presentation. You will need to save the screen or browser window to save the images you create. On the Macintosh, you type open apple-shift-3 to make a Picture file on the hard drive. You can edit these files with Adobe Photoshop or other image editing applications and put them in your report. On a PC with Windows 95, you can type the key combination of "print screen" and the alt key to save what you have displayed in the browser window to the clipboard and then paste it into an image editing application or directly into your report. Create a Quadrat Using Real Data.

45

On the extraction of laminar flame speed and Markstein length from outwardly propagating spherical flames  

SciTech Connect (OSTI)

Large discrepancies among the laminar flame speeds and Markstein lengths of methane/air mixtures measured by different researchers using the same constant-pressure spherical flame method are observed. As an effort to reduce these discrepancies, one linear model (LM, the stretched flame speed changes linearly with the stretch rate) and two non-linear models (NM I and NM II, the stretched flame speed changes non-linearly with the stretch rate) for extracting the laminar flame speed and Markstein length from propagating spherical flames are investigated. The accuracy and performance of the LM, NM I, and NM II are found to strongly depend on the Lewis number. It is demonstrated that NM I is the most accurate for mixtures with large Lewis number (positive Markstein length) while NM II is the most accurate for mixtures with small Lewis number (negative Markstein length). Therefore, in order to get accurate laminar flame speed and Markstein length from spherical flame experiments, different non-linear models should be used for different mixtures. The validity of the theoretical results is further demonstrated by numerical and experimental studies. The results of this study can be used directly in spherical flame experiments measuring the laminar flame speed and Markstein length. (author)

Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China)

2011-02-15T23:59:59.000Z

46

Model flames in the Boussinesq limit: Rising Natalia Vladimirova  

E-Print Network [OSTI]

Model flames in the Boussinesq limit: Rising bubbles Natalia Vladimirova ASC/Flash Center the Boussinesq buoyancy approximation, we study a bubble of reaction products rising in the reactant fluid under with a specified speed. The flame speed, although known for laminar flame, is #12;Model flames in the Boussinesq

Vladimirova, Natalia

47

Aromatics oxidation and soot formation in flames  

SciTech Connect (OSTI)

This project is concerned with the kinetics and mechanisms of aromatics oxidation and soot and fullerenes formation in flames. The scope includes detailed measurements of profiles of stable and radical species concentrations in low-pressure one-dimensional premixed flames. Intermediate species identifications and mole fractions, fluxes, and net reaction rates calculated from the measured profiles are used to test postulated reaction mechanisms. Particular objectives are to identify and to determine or confirm rate constants for the main benzene oxidation reactions in flames, and to characterize fullerenes and their formation mechanisms and kinetics.

Howard, J.B.; Pope, C.J.; Shandross, R.A.; Yadav, T. [Massachusetts Institute of Technology, Cambridge (United States)

1993-12-01T23:59:59.000Z

48

Electric fields effect on liftoff and blowoff of nonpremixed laminar jet flames in a coflow  

SciTech Connect (OSTI)

The stabilization characteristics of liftoff and blowoff in nonpremixed laminar jet flames in a coflow have been investigated experimentally for propane fuel by applying AC and DC electric fields to the fuel nozzle with a single-electrode configuration. The liftoff and blowoff velocities have been measured by varying the applied voltage and frequency of AC and the voltage and the polarity of DC. The result showed that the AC electric fields extended the stabilization regime of nozzle-attached flame in terms of jet velocity. As the applied AC voltage increased, the nozzle-attached flame was maintained even over the blowout velocity without having electric fields. In such a case, a blowoff occurred directly without experiencing a lifted flame. While for the DC cases, the influence on liftoff was minimal. There existed three different regimes depending on the applied AC voltage. In the low voltage regime, the nozzle-detachment velocity of either liftoff or blowoff increased linearly with the applied voltage, while nonlinearly with the AC frequency. In the intermediate voltage regime, the detachment velocity decreased with the applied voltage and reasonably independent of the AC frequency. At the high voltage regime, the detachment was significantly influenced by the generation of discharges. (author)

Kim, M.K.; Ryu, S.K.; Won, S.H. [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 151-742 (Korea); Chung, S.H. [Clean Combustion Research Center, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

2010-01-15T23:59:59.000Z

49

Enol Intermediates Unexpectedly Found in Flames  

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

Enol Intermediates Unexpectedly Found in Flames Print Enol Intermediates Unexpectedly Found in Flames Print For those studying flame chemistry and the properties of combustion intermediates by means of molecular beam mass spectrometry, the addition of tunable vacuum ultraviolet (VUV) from a synchrotron to photoionize the beam for mass spectrometry makes for a powerful technique capable of differentiating between isomers with the same molecular weight and composition. With the help of a unique experimental apparatus, an international team of American, Chinese, and German researchers has exploited this selectivity to identify chemical compounds known as enols as apparently ubiquitous intermediates in flames burning a variety of fuels. This surprising observation will require combustion modelers to revise their models to account for the presence of these compounds.

50

Enol Intermediates Unexpectedly Found in Flames  

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

Enol Intermediates Unexpectedly Found in Flames Print Enol Intermediates Unexpectedly Found in Flames Print For those studying flame chemistry and the properties of combustion intermediates by means of molecular beam mass spectrometry, the addition of tunable vacuum ultraviolet (VUV) from a synchrotron to photoionize the beam for mass spectrometry makes for a powerful technique capable of differentiating between isomers with the same molecular weight and composition. With the help of a unique experimental apparatus, an international team of American, Chinese, and German researchers has exploited this selectivity to identify chemical compounds known as enols as apparently ubiquitous intermediates in flames burning a variety of fuels. This surprising observation will require combustion modelers to revise their models to account for the presence of these compounds.

51

Enol Intermediates Unexpectedly Found in Flames  

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

Enol Intermediates Unexpectedly Found in Flames Print Enol Intermediates Unexpectedly Found in Flames Print For those studying flame chemistry and the properties of combustion intermediates by means of molecular beam mass spectrometry, the addition of tunable vacuum ultraviolet (VUV) from a synchrotron to photoionize the beam for mass spectrometry makes for a powerful technique capable of differentiating between isomers with the same molecular weight and composition. With the help of a unique experimental apparatus, an international team of American, Chinese, and German researchers has exploited this selectivity to identify chemical compounds known as enols as apparently ubiquitous intermediates in flames burning a variety of fuels. This surprising observation will require combustion modelers to revise their models to account for the presence of these compounds.

52

The structure of the carbon black flame  

E-Print Network [OSTI]

THE STRUCTURE OF THE CARBON BLACK FLAME A Dissertation By W1 111 ami Kermit Anderson THEHSR UCOF Approval as to style and content recommended Head of tiie Department of Chemistry A Dissertation Submitted to the Faculty of the Agricultural... and Mechanical College of. Texas in Parti ail Fulfilment of the Requirements for the Degree of Doctor of Philosophy THE STRUCTURE OF THE CARBON BLACK FLAME Major Subject: Chemistry AB William Hermit Anderson:\\ t * August 1945 THE STRUCTURE OF THE. CARBON...

Anderson, W. Kermi

1945-01-01T23:59:59.000Z

53

Effects of Fuel-Side Nitrogen Dilution on Structure and NOx Formation of Turbulent Syngas Non-premixed Jet Flames  

Science Journals Connector (OSTI)

In this syngas non-premixed burner, the nozzle inner and outer diameters are 7.72 mm and 9.46 mm, respectively. ... Prathap, C.; Ray, A.; Ravi, M. R.Investigation of nitrogen dilution effects on laminar burning velocity and flame stability of syngas fuel at atmospheric condition Combust. ...

Jeongwon Lee; Sangwoon Park; Yongmo Kim

2012-05-01T23:59:59.000Z

54

Flames in Type Ia Supernova: Deflagration-Detonation Transition in the Oxygen Burning Flame  

E-Print Network [OSTI]

Flames in Type Ia Supernova: Deflagration-Detonation Transition in the Oxygen Burning Flame S. E of these regions can be supersonic and could initiate a detonation. Subject headings: supernovae: general a late time transition of the thermonuclear burning to a detonation wave (e.g., Hoflich et al. 1995

55

Characterization of syngas laminar flames using the Bunsen burner configuration  

Science Journals Connector (OSTI)

Laminar flame speeds of syngas mixtures (H2/CO/Air) have been studied using the Bunsen flame configuration with both straight and nozzle burners. The flame surface area and flame cone angle methodologies, respectively based on the OH* chemiluminescence and Schlieren imaging techniques, have been performed to extract flame speeds for a wide range of equivalence ratios (0.3 syngas flames with 0.6 < ? < 1.0 and 10% < %H2 < 70% is proposed. A particular attention has been devoted to the development and validation of the OH* chemiluminescence methodology with the identification of important parameters governing the measurement accuracy.

N. Bouvet; C. Chauveau; I. Gökalp; S.-Y. Lee; R.J. Santoro

2011-01-01T23:59:59.000Z

56

VIRTUAL PRESENTERS: TOWARDS INTERACTIVE VIRTUAL PRESENTATIONS  

E-Print Network [OSTI]

the interesting parts of a sculpture or painting, addressing one, several or all persons in his or her audience be a painting, displayed and explained in a virtual museum environment. There are many examples of research they aim at giving the presentation task to a robot or virtual agent. In the latter case we can have one

Nijholt, Anton

57

Autonomous Virtual Mobile Nodes  

E-Print Network [OSTI]

This paper presents a new abstraction for virtual infrastructure in mobile ad hoc networks. An AutonomousVirtual Mobile Node (AVMN) is a robust and reliable entity that is designed to cope with theinherent difficulties ...

Dolev, Shlomi

2005-06-15T23:59:59.000Z

58

Linear stability analysis of laminar premixed spray flames  

Science Journals Connector (OSTI)

...post- ame region and will chill it due to their absorption of heat for vaporiza- tion...endothermicity increases, due to absorption of heat for vaporization by...is due to heat loss from the absorption of heat by the droplets for...

2001-01-01T23:59:59.000Z

59

1 - Mapping virtual worlds  

Science Journals Connector (OSTI)

Abstract Virtual worlds are many and varied. In investigating the scope of virtual communities, it is important to understand social and theoretical issues that impact online participants. Such issues as gender, ontology, socio-technological integration, and corporeal interface all impact exploration of virtual worlds.

Woody Evans

2011-01-01T23:59:59.000Z

60

Response of a laminar premixed flame to flow oscillations: A kinematic model and thermoacoustic instability results  

SciTech Connect (OSTI)

Combustion instability is a resonance phenomenon that arises due to the coupling between the system acoustics and the unsteady heat release. The constructive feedback between the two processes, which is known to occur as a certain phase relationship between the pressure and the unsteady heat release rate is satisfied, depends on many parameters among which is the acoustic mode, the flame holder characteristics, and the dominant burning pattern. In this paper, the authors construct an analytical model to describe the dynamic response of a laminar premixed flame stabilized on the rim of a tube to velocity oscillation. They consider uniform and nonuniform velocity perturbations superimposed on a pipe flow velocity profile. The model results show that the magnitude of heat release perturbation and its phase with respect to the dynamic perturbation dependent primarily on the flame Strohal number, representing the ratio of the dominant frequency times the tube radius to the laminar burning velocity. In terms of this number, high-frequency perturbations pass through the flame while low frequencies lead to a strong response. The phase with respect to the velocity perturbation behaves in the opposite way. Results of this model are shown to agree with experimental observations and to be useful in determining how the combustion excited model is selected among all the acoustic unstable modes. The model is then used to obtain a time-domain differential equation describing the relationship between the velocity perturbation and the heat release response over the entire frequency range.

Fleifil, M.; Annaswamy, A.M.; Ghoneim, A.F. [Massachusetts Inst. of Technology, Cambridge, MA (United States)] [Massachusetts Inst. of Technology, Cambridge, MA (United States); Ghoneim, Z.A. [Ain Shams Univ., Abassia (Egypt)] [Ain Shams Univ., Abassia (Egypt)

1996-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Testing of a Hydrogen Diffusion Flame Array Injector at Gas Turbine Conditions  

SciTech Connect (OSTI)

High-hydrogen gas turbines enable integration of carbon sequestration into coal-gasifying power plants, though NO{sub x} emissions are often high. This work explores nitrogen dilution of hydrogen diffusion flames to reduce thermal NO{sub x} emissions and avoid problems with premixing hydrogen at gas turbine pressures and temperatures. The burner design includes an array of high-velocity coaxial fuel and air injectors, which balances stability and ignition performance, combustor pressure drop, and flame residence time. Testing of this array injector at representative gas turbine conditions (16 atm and 1750 K firing temperature) yields 4.4 ppmv NO{sub x} at 15% O{sub 2} equivalent. NO{sub x} emissions are proportional to flame residence times, though these deviate from expected scaling due to active combustor cooling and merged flame behavior. The results demonstrate that nitrogen dilution in combination with high velocities can provide low NO{sub x} hydrogen combustion at gas turbine conditions, with significant potential for further NO{sub x} reductions via suggested design changes.

Weiland, Nathan T.; Sidwell, Todd G.; Strakey, Peter A.

2013-07-03T23:59:59.000Z

62

Synergistic effect of nanosilica aerogel with phosphorus flame retardants on improving flame retardancy and leaching resistance of wood  

Science Journals Connector (OSTI)

Nanosilica (Nano-SiO2) sol fabricated by a sol-gel process was introduced into wood modification with phosphorus flame retardants to improve the flame retardancy and leaching resistance of wood. The obtained materials were characterized by ...

Xiaodan Zhu, Yiqiang Wu, Cuihua Tian, Yan Qing, Chunhua Yao

2014-01-01T23:59:59.000Z

63

White Flame Energy switches to backhoes  

SciTech Connect (OSTI)

The mountaintop coal operator, White Flame Energy has switched to different truck-shovel arrangement. Along with many surface mining operations throughout central Appalachia, the company is using hoe-configured hydraulic excavators as opposed to the traditional front-shovel arrangements. Located in Varney, WV, White Flame Energy uses two Terex O & K mining shovels, an RH170 and an RH 200, which have the capacity to move 2 million cu yards per month from five seams, primarily the Coalburg, Stockton, and No 5 Block and associated rider seams. The article records conversations on the operations with Mike Vines, the general manager, and Don Nicewonder, the owner of White Flame Energy. 2 photos.

Fiscor, S.

2005-06-01T23:59:59.000Z

64

A Universal Detector for Liquid Chromatography: The Flame Aerosol Detector  

Science Journals Connector (OSTI)

......a turbu- lent air-hydrogen flame into which the...application of calibration methods similar to those often...of the flame as one method of production of charged droplets...case. In the air-hydrogen flame of a conventional......

Stephen A. Wise; Richard A. Mowery; Jr; Richard S. Juvet; Jr

1979-11-01T23:59:59.000Z

65

Flame Spectra in the Photographic Infra-Red  

Science Journals Connector (OSTI)

...H O bands in the flame of moist carbon monoxide indicates that in this flame the excitation is a result of the combustion processes; this agrees with earlier theories on the formation of vibrationally activated molecules of CO in this flame...

1942-01-01T23:59:59.000Z

66

Computatonal and experimental study of laminar flames  

SciTech Connect (OSTI)

This research has centered on an investigation of the effects of complex chemistry and detailed transport on the structure and extinction of hydrocarbon flames in counterflow, cylindrical and coflowing axisymmetric configurations. The authors have pursued both computational and experimental aspects of the research in parallel. The computational work has focused on the application of accurate and efficient numerical methods for the solution of the one and two-dimensional nonlinear boundary value problems describing the various reacting systems. Detailed experimental measurements were performed on axisymmetric coflow flames using two-dimensional imaging techniques. In particular, spontaneous Raman scattering and laser induced fluorescence were used to measure the temperature, major and minor species profiles.

Smooke, M.D.; Long, M.B. [Yale Univ., New Haven, CT (United States)

1993-12-01T23:59:59.000Z

67

A Numerical Study of the Superadiabatic Flame Temperature Phenomenon in HN3 Flame O. P. Korobeinichev,a  

E-Print Network [OSTI]

@cua.edu #12;2 ABSTRACT The phenomenon of superadiabatic flame temperature (SAFT) was discovered the revised mechanism. The results demonstrate presence of the SAFT phenomenon in the HN3/N2 flame. Analysis of the flame structure and the kinetic mechanism indicates that the cause of SAFT is in the kinetic mechanism

Knyazev, Vadim D.

68

Power-Law Wrinkling Turbulence-Flame Interaction Model for Astrophysical Flames  

E-Print Network [OSTI]

We extend a model for turbulence-flame interactions (TFI) to consider astrophysical flames with a particular focus on combustion in type Ia supernovae. The inertial range of the turbulent cascade is nearly always under-resolved in simulations of astrophysical flows, requiring the use of a model in order to quantify the effects of subgrid-scale wrinkling of the flame surface. We provide implementation details to extend a well-tested TFI model to low-Prandtl number flames for use in the compressible hydrodynamics code FLASH. A local, instantaneous measure of the turbulent velocity is calibrated for FLASH and verification tests are performed. Particular care is taken to consider the relation between the subgrid rms turbulent velocity and the turbulent flame speed, especially for high-intensity turbulence where the turbulent flame speed is not expected to scale with the turbulent velocity. Finally, we explore the impact of different TFI models in full-star, three-dimensional simulations of type Ia supernovae.

Jackson, Aaron P; Calder, Alan C

2014-01-01T23:59:59.000Z

69

Increased Cytotoxicity of Oxidized Flame Soot  

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

Increased Cytotoxicity of Oxidized Flame Soot Increased Cytotoxicity of Oxidized Flame Soot Title Increased Cytotoxicity of Oxidized Flame Soot Publication Type Journal Article Year of Publication 2012 Authors Holder, Amara L., Brietta J. Carter, Regine Goth-Goldstein, Donald Lucas, and Catherine P. Koshland Journal Atmospheric Pollution Research Volume 3 Start Page 25 Issue 1 Pagination 25-31 Date Published 01/2012 Keywords health effects, ozone, soot, toxicity Abstract Combustion-generated particles released into the atmosphere undergo reactions with oxidants, which can change the particles' physiochemical characteristics. In this work, we compare the physical and chemical properties and cellular response of particles fresh from a flame with those oxidized by ozone and nitrogen dioxide. The reaction with ozone and nitrogen dioxide does not significantly modify the physical characteristics of the particles (primary particle size, fractal dimension, and surface area). However, oxidation affects the chemical characteristics of the particles, creating more oxygen and nitrogen containing functional groups, and increases their hydrophilicity. In addition, oxidized soot generates more reactive oxygen species, as measured by the dithiothreitol (DTT) assay. Furthermore, oxidized soot is 1.5-2 times more toxic than soot that was not reacted with ozone, but the inflammatory response, measured by interleukin-8 (IL-8) secretion, is unchanged. These results imply that combustion-generated particles released into the atmosphere will have an increased toxicity on or after high ozone days.

70

Spectrum of the Flame of Ethylene  

Science Journals Connector (OSTI)

1 December 1934 research-article Spectrum of the Flame of Ethylene W. M. Vaidya The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences. www.jstor.org

1934-01-01T23:59:59.000Z

71

Detailed investigation of a pulverized fuel swirl flame in CO{sub 2}/O{sub 2} atmosphere  

SciTech Connect (OSTI)

A novel approach to oxycoal flame stabilization has been developed at the Institute of Heat and Mass Transfer at RWTH Aachen University [D. Toporov, M. Foerster, R. Kneer, in: Third Int. Conf. on Clean Coal Technologies for Our Future, Cagliari, Sardinia, Italy, 15-17 May 2007]. The swirl burner design and its operating conditions have been adjusted in order to enforce CO formation thus stabilizing the flame and obtaining a full burnout at levels of O{sub 2} content in the O{sub 2}/CO{sub 2} mixture similar to those in air. The paper presents results of detailed numerical and experimental investigations of a stable oxy-fired pulverized coal swirl flame (type-2) obtained with a 21 vol% O{sub 2} concentration. The combustion tests were performed in a vertical pilot-scale furnace (100 kW{sub th}) in the framework of the OXYCOAL-AC research project aiming to develop a membrane-based oxyfuel process. The experimental results concerning gas velocities, gas and particle temperatures, and gas compositions are presented and discussed, focusing on the underlying mechanisms as well as on the aerodynamics of the oxycoal flame. A comparison between measurements and simulations has shown the validity of the numerical method used. The reported data set can be used for validation of numerical models developed for prediction of oxyfuel combustion. (author)

Toporov, D.; Bocian, P.; Heil, P.; Kellermann, A.; Stadler, H.; Tschunko, S.; Foerster, M.; Kneer, R. [Institute of Heat and Mass Transfer, RWTH Aachen University, Eilfschornsteinstrasse 18, D-52056 Aachen (Germany)

2008-12-15T23:59:59.000Z

72

Flame quality monitor system for fixed firing rate oil burners  

DOE Patents [OSTI]

A method and apparatus for determining and indicating the flame quality, or efficiency of the air-fuel ratio, in a fixed firing rate heating unit, such as an oil burning furnace, is provided. When the flame brightness falls outside a preset range, the flame quality, or excess air, has changed to the point that the unit should be serviced. The flame quality indicator output is in the form of lights mounted on the front of the unit. A green light indicates that the flame is about in the same condition as when the burner was last serviced. A red light indicates a flame which is either too rich or too lean, and that servicing of the burner is required. At the end of each firing cycle, the flame quality indicator goes into a hold mode which is in effect during the period that the burner remains off. A yellow or amber light indicates that the burner is in the hold mode. In this mode, the flame quality lights indicate the flame condition immediately before the burner turned off. Thus the unit can be viewed when it is off, and the flame condition at the end of the previous firing cycle can be observed.

Butcher, Thomas A. (Pt. Jefferson, NY); Cerniglia, Philip (Moriches, NY)

1992-01-01T23:59:59.000Z

73

Remotely Deployed Virtual Sensors  

E-Print Network [OSTI]

Remotely Deployed Virtual Sensors TR-UTEDGE-2007-010 Sanem Kabadayi Christine Julien © Copyright 2007 The University of Texas at Austin #12;Remotely Deployed Virtual Sensors Sanem Kabadayi that run on mobile client devices connect to the sensors of a multihop sensor network. For emerging

Julien, Christine

74

Virtual Circuits (OSCARS)  

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

Virtual Circuits (OSCARS) Virtual Circuits (OSCARS) Services Overview ECS Audio/Video Conferencing Fasterdata IPv6 Network Network Performance Tools (perfSONAR) ESnet OID Registry PGP Key Service Virtual Circuits (OSCARS) OSCARS Case Study Documentation Links Hardware Requirements DOE Grids Service Transition Contact Us Technical Assistance: 1 800-33-ESnet (Inside the US) 1 800-333-7638 (Inside the US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network Problems: trouble@es.net Provide Web Site Feedback: info@es.net Virtual Circuits (OSCARS) ESnet's On-Demand Secure Circuits and Advance Reservation System (OSCARS) provides multi-domain, high-bandwidth virtual circuits that guarantee end-to-end network data transfer performance. Originally a research concept, OSCARS has grown into a robust production service. Currently

75

Turbulent Nonpremixed Flames (TNF): Experimental Data Archives and Computational Submodels  

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

In the 1990s an international collaboration formed around a series of workshops that became known collectively as the International Workshop on Measurement and Computation of Turbulent Non-Premixed Flames (TNF). An online library, hosted by Sandia National Laboratory (California) was established that provides data sets and submodels or "mechanisms" for the study of turbulence-chemistry interactions in turbulent nonpremixed and partially premixed combustion. Data are organized by flame types: simple jet flames, piloted jet flames, bluff body flames, and swirl flames. These data sets provide a means for collaborative comparisons of both measured and simulated/modeled research results and also assist scientists in determining priorities for further research. More than 20 data sets or databases are available from this website, along with various downloadable files of chemical mechanisms. The website also provides an extensive bibliography and the proceedings of the workshops themselves from 1996 through 2012. Information continues to be added to this collection.

76

New developments in the theory of flame propagation  

SciTech Connect (OSTI)

Two topics in combustion fluid mechanics are discussed. The first is a theory of the outward propagating spherical flame in the regime of well-developed hydrodynamic instability. In a qualitative agreement with experimental observations it is shown that the flame assumes a fractal-like wrinkled structure resulting in the overall burning rate acceleration. In contrast to hydrodynamically unstable flames, the expanding flame subject exclusively to the effect of diffusive instability does not indicate any disposition toward acceleration. The second topic concerns the dynamics of diffusively unstable flames subjected to radiative heat losses. At high enough heat losses the flame breaks up into separate self-propagating cap-like flamelets while a significant portion of the fuel remains unconsumed.

Sivashinsky, G.I. [City College of the City Univ. of New York, NY (United States)

1996-12-31T23:59:59.000Z

77

The advanced flame quality indicator system  

SciTech Connect (OSTI)

By combining oil tank monitoring, systems diagnostics and flame quality monitoring in an affordable system that communicates directly with dealers by telephone modem, Insight Technologies offers new revenue opportunities and the capability for a new order of customer relations to oil dealers. With co-sponsorship from New York State Energy Research and Development Authority, we have incorporated several valuable functions to a new product based on the original Flame Quality Indicator concept licensed from the US DOE`s Brookhaven National Laboratory. The new system is the Advanced Flame Quality Indicator, or AFQI. As before, the AFQI monitors and reports the intensity of the burner flame relative to a calibration established when the burner is set up at AFQI installation. Repairs or adjustments are summoned by late-night outgoing telephone calls when limits are exceeded in either direction, indicating an impending contamination or other malfunction. A independently, a pressure transducer for monitoring oil tank level and filter condition, safety lockout alarms and a temperature monitor; all reporting automatically at instructed intervals via an on-board modem to a central station PC computer (CSC). Firmware on each AFQI unit and Insight-supplied software on the CSC automatically interact to maintain a customer database for an oil dealer, an OEM, or a regional service contractor. In addition to ensuring continuously clean and efficient operation, the AFQI offers the oil industry a new set of immediate payoffs, among which are reduced outages and emergency service calls, shorter service calls from cleaner operation, larger oil delivery drops, the opportunity to stretch service intervals to as along as three years in some cases, new selling features to keep and attract customers, and greatly enhanced customer contact, quality and reliability.

Oman, R.; Rossi, M.J.; Calia, V.S.; Davis, F.L.; Rudin, A. [Insight Technologies, Inc., Bohemia, NY (United States)

1997-09-01T23:59:59.000Z

78

Virtual Teams Demystified: An Integrative Framework for Understanding Virtual Teams  

Science Journals Connector (OSTI)

Virtual teams have been researched intensely in the last ten years and there is a growing body of literature on the topic. At this point, the authors need an integrative theory-driven framework through which they can conceptualize the notion of virtual ... Keywords: Emergent Team Processes, Emergent Team States, Information Technology, Team Design, Virtual Team Effectiveness, Virtual Teams

Olivier Caya; Mark Mortensen; Alain Pinsonneault

2013-04-01T23:59:59.000Z

79

Virtual vision: visual sensor networks in virtual reality  

Science Journals Connector (OSTI)

The virtual vision paradigm features a unique synergy of computer graphics, artificial life, and computer vision technologies. Virtual vision prescribes visually and behaviorally realistic virtual environments as a simulation tool in support of research ... Keywords: reality emulator, smart cameras, virtual vision

Faisal Z. Qureshi; Demetri Terzopoulos

2007-11-01T23:59:59.000Z

80

Advancing predictive models for particulate formation in turbulent flames via massively parallel direct numerical simulations  

Science Journals Connector (OSTI)

...gaseous flames in gas turbine combustion chambers...using a flamelet/progress variable approach...flame of natural gas. Combust. Flame...and R Suntz. 2002 Progress in characterization...calculations. Technical report, University of Technology...

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Flame-wall interaction simulation in a turbulent channel flow  

SciTech Connect (OSTI)

The interaction between turbulent premixed flames and channel walls is studied. Combustion is represented by a simple irreversible reaction with a large activation temperature. A low heat release assumption is used, but feedback to the flowfield can be allowed through viscosity changes. The effect of wall distance on local and global flame structure is investigated. Quenching distances and maximum wall heat fluxed computed in laminar cases are compared to DNS results. It is found that quenching distances decrease and maximum heat fluxes increase relative to laminar flame values, scaling with the turbulent strain rate. It is shown that these effects are due to large coherent structures which push flame elements towards the wall. The effect of wall strain in flame-wall interaction is studied in a stagnation line flow; this is used to explain the DNS results. The effects of the flame on the flow through viscosity changes is studied. It is also shown that remarkable flame events are produced by flame interaction with a horseshoe vortex: burned gases are pushed towards the wall at high speed and induce quenching and high wall heat flux while fresh gases are expelled from the wall region and form finger-like structures. Effects of the wall on flame surface density are investigated.

Bruneaux, G.; Akselvoll, K.; Poinsot, T.; Ferziger, J.H.

1996-10-01T23:59:59.000Z

82

Surface wettability studies of PDMS using flame plasma treatment .  

E-Print Network [OSTI]

??The flame plasma treatment studied in this thesis was able to oxidize the surface of Polydimethylsiloxane (PDMS) in a fraction of a second. It was… (more)

Wang, Xin C

2009-01-01T23:59:59.000Z

83

FIELD TEST OF THE FLAME QUALITY INDICATOR  

SciTech Connect (OSTI)

The flame quality indicator concept was developed at BNL specifically to monitor the brightness of the flame in a small oil burner and to provide a ''call for service'' notification when the brightness has changed from its setpoint, either high or low. In prior development work BNL has explored the response of this system to operational upsets such as excess air changes, fouled atomizer nozzles, poor fuel quality, etc. Insight Technologies, Inc. and Honeywell, Inc. have licensed this technology from the U.S. Department of Energy and have been cooperating to develop product offerings which meet industry needs with an optimal combination of function and price. Honeywell has recently completed the development of the Flame Quality Monitor (FQM or Honeywell QS7100F). This is a small module which connects via a serial cable to the burners primary operating control. Primary advantages of this approach are simplicity, cost, and ease of installation. Call-for-service conditions are output in the form of front panel indicator lights and contact closure which can trigger a range of external communication options. Under this project a field test was conducted of the FQM in cooperation with service organizations in Virginia, Pennsylvania, New Jersey, New York, and Connecticut. At total of 83 field sites were included. At each site the FQM was installed in parallel with another embodiment of this concept--the Insight AFQI. The AFQI incorporates a modem and provides the ability to provide detailed information on the trends in the flame quality over the course of the two year test period. The test site population was comprised of 79.5% boilers, 13.7% warm air furnaces, and 6.8% water heaters. Nearly all were of residential size--with firing rates ranging from 0.6 gallons of oil per hour to 1.25. During the course of the test program the monitoring equipment successfully identified problems including: plugged fuel lines, fouled nozzles, collapsed combustion chambers, and poor fuel pump cut-off. Service organizations can use these early indications to reduce problems and service costs. There were also some ''call-for-service'' indications for which problems were not identified. The test program also showed that monitoring of the flame can provide information on burner run times and this can be used to estimate current oversize factors and to determine actual fuel usage, enabling more efficient fuel delivery procedures.

Andrew M. Rudin; Thomas Butcher; Henry Troost

2003-02-04T23:59:59.000Z

84

E-Print Network 3.0 - atomic absorption flame Sample Search Results  

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

flame Search Powered by Explorit Topic List Advanced Search Sample search results for: atomic absorption flame Page: << < 1 2 3 4 5 > >> 1 Appendix 1: Experimental Studies...

85

ARM - Measurement - Virtual temperature  

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

govMeasurementsVirtual temperature govMeasurementsVirtual temperature ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Virtual temperature The virtual temperature Tv = T(1 + rv/{epsilon}), where rv is the mixing ratio, and {epsilon} is the ratio of the gas constants of air and water vapor ( 0.622). Categories Atmospheric State Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or quality assurance purposes. ARM Instruments CO2FLX : Carbon Dioxide Flux Measurement Systems MWRP : Microwave Radiometer Profiler RWP : Radar Wind Profiler

86

Virtual planetarium in cyberstage  

Science Journals Connector (OSTI)

We describe an educational application in virtual environment, intended for teaching and demonstration of basics of astronomy. The application includes 3D models of 30 objects in the Solar System, 3200 nearby stars, a large database, containing textual ...

Valery Burkin; Martin Göbel; Frank Hasenbrink; Stanislav Klimenko; Igor Nikitin; Henrik Tramberend

2000-06-01T23:59:59.000Z

87

Jefferson Lab Virtual Tour  

ScienceCinema (OSTI)

Take a virtual tour of the campus of Thomas Jefferson National Accelerator Facility. You can see inside our two accelerators, three experimental areas, accelerator component fabrication and testing areas, high-performance computing areas and laser labs.

None

2014-05-22T23:59:59.000Z

88

Cellular burning in lean premixed turbulent hydrogen-air flames: Coupling experimental and computational analysis at the laboratory scale  

Science Journals Connector (OSTI)

One strategy for reducing US dependence on petroleum is to develop new combustion technologies for burning the fuel-lean mixtures of hydrogen or hydrogen-rich syngas fuels obtained from the gasification of coal and biomass. Fuel-flexible combustion systems based on lean premixed combustion have the potential for dramatically reducing pollutant emissions in transportation systems, heat and stationary power generation. However, lean premixed flames are highly susceptible to fluid-dynamical combustion instabilities making robust and reliable systems difficult to design. Low swirl burners are emerging as an important technology for meeting design requirements in terms of both reliability and emissions for next generation combustion devices. In this paper, we present simulations of a lean, premixed hydrogen flame stabilized on a laboratory-scale low swirl burner. The simulations use detailed chemistry and transport without incorporating explicit models for turbulence or turbulence/chemistry interaction. Here we discuss the overall structure of the flame and compare with experimental data. We also use the simulation data to elucidate the characteristics of the turbulent flame interaction and how this impacts the analysis of experimental measurements.

M S Day; J B Bell; R K Cheng; S Tachibana; V E Beckner; M J Lijewski

2009-01-01T23:59:59.000Z

89

Introduction HYBRID FLAME: combustion of a combustible gas and  

E-Print Network [OSTI]

in numerous cases (e.g. explosion in coal mines) QUENCHING DISTANCES: narrowest passage through which aflame due to the difficulty of obtaining a hybrid flame. Setup Methodology Dust fed by actuator with methane Future Work Verify data obtained for methane and aluminum flame Run test with constant equivalence ratio

Barthelat, Francois

90

Low-Temperature Oxidation and Cool Flames of Propane  

Science Journals Connector (OSTI)

...1954 research-article Low-Temperature Oxidation and Cool Flames of Propane J. H. Knox R. G. W. Norrish A detailed analytical study of the cool-flame oxidation of propane has been carried out using a continuous-flow technique with a view...

1954-01-01T23:59:59.000Z

91

Author's personal copy Combustion and Flame 151 (2007) 104119  

E-Print Network [OSTI]

Author's personal copy Combustion and Flame 151 (2007) 104­119 www May 2007 Available online 28 June 2007 Abstract Laminar flame speeds of lean H2/CO/CO2 (syngas) fuel but overpredict the measurements at higher temperatures. © 2007 The Combustion Institute. Published by Elsevier

Lieuwen, Timothy C.

92

Analyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames  

E-Print Network [OSTI]

of premixed burners capable of stably burning ultra-lean hydrogen-air fuel mixtures. Such burners couldAnalyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames Peer-Timo Bremer, Member demonstrate our approach by analyzing three numerical simulations of lean hydrogen flames subject to different

Pascucci, Valerio

93

On the Evolution of Thermonuclear Flames on Large Scales  

Science Journals Connector (OSTI)

The thermonuclear explosion of a massive white dwarf in a Type Ia supernova explosion is characterized by vastly disparate spatial and temporal scales. The extreme dynamic range inherent to the problem prevents the use of direct numerical simulation and forces modelers to resort to subgrid models to describe physical processes taking place on unresolved scales. We consider the evolution of a model thermonuclear flame in a constant gravitational field on a periodic domain. The gravitational acceleration is aligned with the overall direction of the flame propagation, making the flame surface subject to the Rayleigh-Taylor instability. The flame evolution is followed through an extended initial transient phase well into the steady state regime. The properties of the evolution of flame surface are examined. We confirm the form of the governing equation of the evolution suggested by Khokhlov in 1995. The mechanism of vorticity production and the interaction between vortices and the flame surface are discussed. Previously observed periodic behavior of the flame evolution is reproduced and is found to be caused by the turnover of the largest eddies. The characteristic timescales are found to be similar to the turnover time of these eddies. Relations between flame surface creation and destruction processes and basic characteristics of the flow are discussed. We find that the flame surface creation strength is associated with the Rayleigh-Taylor timescale. Also, in fully developed turbulence, the flame surface destruction strength scales as 1/L3, where L is the turbulent driving scale. The results of our investigation provide support for Khokhlov's self-regulating model of turbulent thermonuclear flames. Based on these results, one can revise and extend the original model. The revision uses a local description of the flame surface enhancement and the evolution of the flame surface since the onset of turbulence, rendering it free from the assumption of an instantaneous steady state of turbulence. This new model can be applied to the initial transient phase of the flame evolution, where the self-regulation mechanism yet to be fully established. Details of this new model will be presented in a forthcoming paper.

Ju Zhang; O. E. Bronson Messer; Alexei M. Khokhlov; Tomasz Plewa

2007-01-01T23:59:59.000Z

94

Investigations of swirl flames in a gas turbine model combustor  

SciTech Connect (OSTI)

A gas turbine model combustor for swirling CH{sub 4}/air diffusion flames at atmospheric pressure with good optical access for detailed laser measurements is discussed. Three flames with thermal powers between 7.6 and 34.9 kW and overall equivalence ratios between 0.55 and 0.75 were investigated. These behave differently with respect to combustion instabilities: Flame A burned stably, flame B exhibited pronounced thermoacoustic oscillations, and flame C, operated near the lean extinction limit, was subject to sudden liftoff with partial extinction and reanchoring. One aim of the studies was a detailed experimental characterization of flame behavior to better understand the underlying physical and chemical processes leading to instabilities. The second goal of the work was the establishment of a comprehensive database that can be used for validation and improvement of numerical combustion models. The flow field was measured by laser Doppler velocimetry, the flame structures were visualized by planar laser-induced fluorescence (PLIF) of OH and CH radicals, and the major species concentrations, temperature, and mixture fraction were determined by laser Raman scattering. The flow fields of the three flames were quite similar, with high velocities in the region of the injected gases, a pronounced inner recirculation zone, and an outer recirculation zone with low velocities. The flames were not attached to the fuel nozzle and thus were partially premixed before ignition. The near field of the flames was characterized by fast mixing and considerable finite-rate chemistry effects. CH PLIF images revealed that the reaction zones were thin (=<0.5 mm) and strongly corrugated and that the flame zones were short (h=<50 mm). Despite the similar flow fields of the three flames, the oscillating flame B was flatter and opened more widely than the others. In the current article, the flow field, structures, and mean and rms values of the temperature, mixture fraction, and species concentrations are discussed. Turbulence intensities, mixing, heat release, and reaction progress are addressed. In a second article, the turbulence-chemistry interactions in the three flames are treated.

Weigand, P.; Meier, W.; Duan, X.R.; Stricker, W.; Aigner, M. [Institut fuer Verbrennungstechnik, Deutsches Zentrum fuer Luft- und Raumfahrt (DLR), Pfaffenwaldring 38, D-70569 Stuttgart (Germany)

2006-01-01T23:59:59.000Z

95

Electrical probe diagnostics for the laminar flame quenching distance  

SciTech Connect (OSTI)

A simplified theory, previously developed for the general case of weakly ionized gas flow, is used to predict electrical probe response when the flame is quenched on the probe surface. This theory is based on the planar model of space charge sheaths around the measuring electrode. For the flame quenching case, by assuming that the sheath thickness is comparable with the thermal boundary layer thickness, probe current can be related to flame quenching distance. The theoretical assumptions made to obtain the analytical formulation of probe current were experimentally proved by using direct visualization and high-frequency PIV. The direct visualization method was also used to validate the results of flame quenching distance values obtained with electrical probe. The electrical probe diagnostics have been verified for both head-on and sidewall flame quenching regimes and for stoichiometric methane/air and propane/air mixtures in a pressure range of 0.05-0.6 MPa. (author)

Karrer, Maxime; Makarov, Maxime [Renault Technocentre, 78288 Guyancourt Cedex (France); Bellenoue, Marc; Labuda, Sergei; Sotton, Julien [Laboratoire de Combustion et de Detonique, CNRS, 86961 Futuroscope Chasseneuil (France)

2010-02-15T23:59:59.000Z

96

Trapping and aerogelation of nanoparticles in negative gravity hydrocarbon flames  

SciTech Connect (OSTI)

We report the experimental realization of continuous carbon aerogel production using a flame aerosol reactor by operating it in negative gravity (?g; up-side-down configuration). Buoyancy opposes the fuel and air flow forces in ?g, which eliminates convectional outflow of nanoparticles from the flame and traps them in a distinctive non-tipping, flicker-free, cylindrical flame body, where they grow to millimeter-size aerogel particles and gravitationally fall out. Computational fluid dynamics simulations show that a closed-loop recirculation zone is set up in ?g flames, which reduces the time to gel for nanoparticles by ?10{sup 6}?s, compared to positive gravity (upward rising) flames. Our results open up new possibilities of one-step gas-phase synthesis of a wide variety of aerogels on an industrial scale.

Chakrabarty, Rajan K., E-mail: rajan.chakrabarty@gmail.com [Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130 (United States); Laboratory for Aerosol Science, Spectroscopy, and Optics, Desert Research Institute, Nevada System of Higher Education, Reno, Nevada 89512 (United States); Novosselov, Igor V. [Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195 (United States); Enertechnix Inc., Maple Valley, Washington 98068 (United States); Beres, Nicholas D.; Moosmüller, Hans [Laboratory for Aerosol Science, Spectroscopy, and Optics, Desert Research Institute, Nevada System of Higher Education, Reno, Nevada 89512 (United States); Sorensen, Christopher M. [Condensed Matter Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States); Stipe, Christopher B. [TSI Incorporated, 500 Cardigan Rd, Shoreview, Minnesota 55126 (United States)

2014-06-16T23:59:59.000Z

97

Turbulence-Flame Interactions in Type Ia Supernovae  

E-Print Network [OSTI]

The large range of time and length scales involved in type Ia supernovae (SN Ia) requires the use of flame models. As a prelude to exploring various options for flame models, we consider, in this paper, high-resolution three-dimensional simulations of the small-scale dynamics of nuclear flames in the supernova environment in which the details of the flame structure are fully resolved. The range of densities examined, 1 to $8 \\times 10^7$ g cm$^{-3}$, spans the transition from the laminar flamelet regime to the distributed burning regime where small scale turbulence disrupts the flame. The use of a low Mach number algorithm facilitates the accurate resolution of the thermal structure of the flame and the inviscid turbulent kinetic energy cascade, while implicitly incorporating kinetic energy dissipation at the grid-scale cutoff. For an assumed background of isotropic Kolmogorov turbulence with an energy characteristic of SN Ia, we find a transition density between 1 and $3 \\times 10^7$ g cm$^{-3}$ where the nature of the burning changes qualitatively. By $1 \\times 10^7$ g cm$^{-3}$, energy diffusion by conduction and radiation is exceeded, on the flame scale, by turbulent advection. As a result, the effective Lewis Number approaches unity. That is, the flame resembles a laminar flame, but is turbulently broadened with an effective diffusion coefficient, $D_T \\sim u' l$, where $u'$ is the turbulent intensity and $l$ is the integral scale. For the larger integral scales characteristic of a real supernova, the flame structure is predicted to become complex and unsteady. Implications for a possible transition to detonation are discussed.

A. J. Aspden; J. B. Bell; M. S. Day; S. E. Woosley; M. Zingale

2008-11-17T23:59:59.000Z

98

Microsoft Virtualization: Master Microsoft Server, Desktop, Application, and Presentation Virtualization  

Science Journals Connector (OSTI)

Virtualization technologies help IT organizations in three ways: cost-cutting, ease of administration, and the overall effect of IT on the environment. Virtualization cuts costs by reducing the amount of capital resources (equipment), power, and cooling ...

Thomas Olzak; James Sabovik; Jason Boomer; Robert M. Keefer

2010-06-01T23:59:59.000Z

99

Experimental and modeling study of the effect of elevated pressure on lean high-hydrogen syngas flames  

Science Journals Connector (OSTI)

Abstract New laminar burning velocity measurements of 85:15% (by volume) H2–CO and H2–N2 mixtures with O2–He oxidizer are reported at lean conditions and elevated pressures (1–10 atm). Experiments are conducted using the heat flux method at initial temperature of 298 K. In this technique a near adiabatic flame is stabilized by balancing the heat loss from the flame to the burner with heat gain to the unburnt gas mixture such that no net heat loss to the burner is observed. A new facility was designed for such high pressure burner stabilized flame experiments. The results obtained are compared with five chemical kinetic schemes from literature for syngas mixtures at elevated pressures. Large differences are observed between the kinetic schemes and the experiments which can be attributed to certain key chemical reactions. A study of the kinetics is performed through reaction rate and sensitivity analysis which indicate that a high uncertainty still remains in important reactions that drive the production and consumption of species such as H, HO2 and OH. For lean mixtures the reaction H + O2(+M) = HO2(+M) contributes significantly to the deviation of models from the experiments. The present analysis in the lean mixture regime suggests the need for further studies in assessment and modification of rate constants for this reaction.

M. Goswami; J.G.H. van Griensven; R.J.M. Bastiaans; A.A. Konnov; L.P.H. de Goey

2014-01-01T23:59:59.000Z

100

Multimodal astronaut virtual training prototype  

Science Journals Connector (OSTI)

A few dedicated training simulator applications exist that mix realistic interaction devices-like real cockpits in flight simulators-with virtual environment (VE) components. Dedicated virtual reality (VR) systems have been utilized also in astronaut ...

Jukka Rönkkö; Jussi Markkanen; Raimo Launonen; Marinella Ferrino; Enrico Gaia; Valter Basso; Harshada Patel; Mirabelle D'Cruz; Seppo Laukkanen

2006-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Improving virtual environments analysis process  

Science Journals Connector (OSTI)

The use of Virtual Environments (VEs) is increasing rapidly and people are demanding easier and more credible ways to interact with these new sites. We define a VE as a special kind of 3D virtual environment, inhabited by avatars which represent humans ... Keywords: analysis process, software engineering, use concept, virtual environment

Maria-Isabel Sánchez-Segura; Angelica De Antonio; Antonio De Amescua

2005-08-01T23:59:59.000Z

102

The hiphop virtual machine  

Science Journals Connector (OSTI)

The HipHop Virtual Machine (HHVM) is a JIT compiler and runtime for PHP. While PHP values are dynamically typed, real programs often have latent types that are useful for optimization once discovered. Some types can be proven through static analysis, ... Keywords: dynamic languages, jit compiler, php, tracelet

Keith Adams, Jason Evans, Bertrand Maher, Guilherme Ottoni, Andrew Paroski, Brett Simmers, Edwin Smith, Owen Yamauchi

2014-10-01T23:59:59.000Z

103

REAL TIME FLAME MONITORING OF GASIFIER BURNER AND INJECTORS  

SciTech Connect (OSTI)

This report is submitted to the United States Department of Energy in partial fulfillment of the contractual requirements for Phase I of the project titled, ''Real Time Flame Monitoring of Gasifier Burner and Injectors'', under co-operative agreement number DE-FS26-02NT41585. The project is composed of three one-year budget periods. The work in each year is divided into separate Tasks to facilitate project management, orderly completion of all project objectives, budget control, and critical path application of personnel and equipment. This Topical Report presents results of the Task 1 and 2 work. The 2 D optical sensor was developed to monitor selected UV and visible wavelengths to collect accurate flame characterization information regarding mixing, flame shape, and flame rich/lean characteristic. Flame richness, for example, was determined using OH and CH intensity peaks in the 300 to 500 nanometer range of the UV and visible spectrum. The laboratory burner was operated over a wide range of air to fuel ratio conditions from fuel rich to fuel lean. The sooty oxygen enriched air flames were established to test the sensor ability to characterize flame structures with substantial presence of hot solid particles emitting strong ''black body radiation''. The knowledge gained in these experiments will be very important when the sensor is used for gasifier flame analyses. It is expected that the sensor when installed on the Global Energy gasifier will be exposed to complex radiation patterns. The measured energy will be a combination of spectra emitted by the combusting gases, hot solid particulates, and hot walls of the gasifier chamber. The ability to separate flame emissions from the ''black body emissions'' will allow the sensor to accurately determine flame location relative to the gasifier walls and the injectors, as well as to analyze the flame's structure and condition. Ultimately, this information should enable the gasification processes to be monitored and controlled and as a result increase durability and efficiency of the gasifier. To accomplish goals set for Task 2 GTI will utilize the CANMET Coal Gasification Research facility. The Entrained Coal Gasifier Burner Test Stand has been designed and is currently under construction in the CANMET Energy Technology Center (CETC), the research and technology arm of Natural Resources Canada (NRCan). This Gasifier Burner Stand (GBS) is a scaled-down mock-up of a working gasifier combustion system that can provide the flexible platform needed in the second year of the project to test the flame sensor. The GBS will be capable of simulating combustion and gasification processes occurring in commercial gasifiers, such as Texaco, Shell, and Wabash River.

James Servaites; Serguei Zelepouga; David Rue

2003-10-01T23:59:59.000Z

104

Study on laminar flame speed and flame structure of syngas with varied compositions using OH-PLIF and spectrograph  

Science Journals Connector (OSTI)

Various Bunsen flame information of premixed syngas/air mixtures was systematically collected. A CCD camera was used to capture the flame images. The OH-PLIF technique was applied to obtain the flame OH distribution and overall flame radiation spectra were measured with a spectrograph. Experiments were conducted on a temperature un-controlled burner and syngas over a wide range of H2/CO ratios (from 0.25 to 4) and equivalence ratios (from 0.5 to 1.2). Results show that increasing hydrogen fraction ( X H 2 ) extends the blow-off limit significantly. The measured laminar flame speed using cone-angle method based on CCD flame imaging and OH-PLIF images increases remarkably with the increase of X H 2 , and these measurements agrees well with kinetic modeling predictions through Li's mechanism when the temperature for computation is corrected. Kinetic study shows that as X H 2 increases, the production of H and OH radicals is accelerated. Additionally, the main H radical production reaction (or OH radical consumption reactions) changes from R29 (CO + OH = CO2 + H) to R3 (H2 + OH = H2O + H) as X H 2 increases. Sensitivity analysis was conducted to access the dominant reactions when X H 2 increases. The difference on flame color for different X H 2 mixtures is due to their difference in radiation spectrum of the intermediate radicals produced in combustion.

Jin Fu; Chenglong Tang; Wu Jin; Luong Dinh Thi; Zuohua Huang; Yang Zhang

2013-01-01T23:59:59.000Z

105

Theoretical Adiabatic Temperature and Chemical Composition of Sodium Combustion Flame  

SciTech Connect (OSTI)

Sodium fire safety analysis requires fundamental combustion properties, e.g., heat of combustion, flame temperature, and composition. We developed the GENESYS code for a theoretical investigation of sodium combustion flame.Our principle conclusions on sodium combustion under atmospheric air conditions are (a) the maximum theoretical flame temperature is 1950 K, and it is not affected by the presence of moisture; the uppermost limiting factor is the chemical instability of the condensed sodium-oxide products under high temperature; (b) the main combustion product is liquid Na{sub 2}O in dry air condition and liquid Na{sub 2}O with gaseous NaOH in moist air; and (c) the chemical equilibrium prediction of the residual gaseous reactants in the flame is indispensable for sodium combustion modeling.

Okano, Yasushi; Yamaguchi, Akira [O-arai Engineering Center (Japan)

2003-12-15T23:59:59.000Z

106

Probing flame chemistry with MBMS, theory, and modeling  

SciTech Connect (OSTI)

The objective is to establish kinetics of combustion and molecular-weight growth in C{sub 3} hydrocarbon flames as part of an ongoing study of flame chemistry. Specific reactions being studied are (1) the growth reactions of C{sub 3}H{sub 5} and C{sub 3}H{sub 3} with themselves and with unsaturated hydrocarbons and (2) the oxidation reactions of O and OH with C{sub 3}`s. This approach combines molecular-beam mass spectrometry (MBMS) experiments on low-pressure flat flames; theoretical predictions of rate constants by thermochemical kinetics, Bimolecular Quantum-RRK, RRKM, and master-equation theory; and whole-flame modeling using full mechanisms of elementary reactions.

Westmoreland, P.R. [Univ. of Massachusetts, Amherst (United States)

1993-12-01T23:59:59.000Z

107

Fuel Properties to Enable Lifted-Flame Combustion  

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

Page 1 E.Kurtz File Name.pptx Fuel Properties to Enable Lifted Flame Combustion Eric Kurtz Ford Motor Company June 19, 2014 FT017 This presentation does not contain any...

108

Modeling variable density effects in turbulent flames -- Some basic considerations  

SciTech Connect (OSTI)

The paper discusses the basic physical phenomena involved in pressure-density interactions, and presents models of pressure-velocity, pressure-scalar, baroclinic and dilatation effects for variable density low Mach-number turbulence. Their implementation in the {kappa}-{epsilon} framework is then described and their performance evaluated. The models assume that both scalar transport and turbulence generation arising from pressure-density interactions in flames are caused by the motion of large scale turbulent thermals superposed on the normal turbulence mechanism. The velocity of the thermals is related directly to the mean pressure gradient and local density differences in the flames. It is furthermore assumed that the correction for dilatation effects in the {kappa}-{epsilon} system can be determined from the constraint of conservation of the angular momentum of turbulence per unit mass. Simple corrections of the {kappa}-{epsilon} system are proposed for fast chemistry diffusion and premixed flames subject to variable pressure gradients, which offer substantial improvements in the predictions of the flames. some problems remain, particularly in predictions of turbulence in premixed flames, owing to large scale instabilities of the flames observed in the experiments.

Chomiak, J.; Nisbet, J.R. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Thermo and Fluid Dynamics] [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Thermo and Fluid Dynamics

1995-08-01T23:59:59.000Z

109

Noise in non?premixed turbulent syngas flames  

Science Journals Connector (OSTI)

A turbulent syngas flame may generate acoustic noise of high acoustic intensity in a combustion chamber. This may lead to the failure of construction components in a gas turbine engine in periods of the order of 1–100 hours. The research as described in the literature has almost exclusively been performed on the generation of noise in premixed methane or propane flames. Syngas fuel is a mixture of hydrogen and carbon monoxide and the burners used are of the non?premixed type. In this research the effect of turbulence and syngas composition on noise generation is investigated. A laboratory is set up to test syngas flames of a thermal power of 50 kW in a cylindrical air?cooled combustion chamber. Experiments are performed at several fuel compositions and burner inlet conditions. The flame sound intensity is measured in the combustion chamber equipped with acoustic dampers. The paper discusses the measured sound spectra. A model is derived for the generation of sound in a turbulent non?premixed flame. In this model it is shown that the sound generation is related to the dependence of density on mixture fraction in a flame with fast chemistry. A fluctuation in mixture fraction will lead to sound generation.

Sikke A. Klein; Jim B. W. Kok

1998-01-01T23:59:59.000Z

110

On the Evolution of Thermonuclear Flames on Large Scales  

E-Print Network [OSTI]

The thermonuclear explosion of a massive white dwarf in a Type Ia supernova explosion is characterized by vastly disparate spatial and temporal scales. The extreme dynamic range inherent to the problem prevents the use of direct numerical simulation and forces modelers to resort to subgrid models to describe physical processes taking place on unresolved scales. We consider the evolution of a model thermonuclear flame in a constant gravitational field on a periodic domain. The gravitational acceleration is aligned with the overall direction of the flame propagation, making the flame surface subject to the Rayleigh-Taylor instability. The flame evolution is followed through an extended initial transient phase well into the steady-state regime. The properties of the evolution of flame surface are examined. We confirm the form of the governing equation of the evolution suggested by Khokhlov (1995). The mechanism of vorticity production and the interaction between vortices and the flame surface are discussed. The results of our investigation provide the bases for revising and extending previous subgrid-scale model.

Ju Zhang; O. E. Bronson Messer; Alexei M. Khokhlov; Tomasz Plewa

2006-10-05T23:59:59.000Z

111

Virtual nuclear weapons  

SciTech Connect (OSTI)

The term virtual nuclear weapons proliferation and arsenals, as opposed to actual weapons and arsenals, has entered in recent years the American lexicon of nuclear strategy, arms control, and nonproliferation. While the term seems to have an intuitive appeal, largely due to its cyberspace imagery, its current use is still vague and loose. The author believes, however, that if the term is clearly delineated, it might offer a promising approach to conceptualizing certain current problems of proliferation. The first use is in a reference to an old problem that has resurfaced recently: the problem of growing availability of weapon-usable nuclear materials in civilian nuclear programs along with materials made `excess` to defense needs by current arms reduction and dismantlement. It is argued that the availability of these vast materials, either by declared nuclear-weapon states or by technologically advanced nonweapon states, makes it possible for those states to rapidly assemble and deploy nuclear weapons. The second use has quite a different set of connotations. It is derived conceptually from the imagery of computer-generated reality. In this use, one thinks of virtual proliferation and arsenals not in terms of the physical hardware required to make the bomb but rather in terms of the knowledge/experience required to design, assemble, and deploy the arsenal. Virtual weapons are a physics reality and cannot be ignored in a world where knowledge, experience, materials, and other requirements to make nuclear weapons are widespread, and where dramatic army reductions and, in some cases, disarmament are realities. These concepts are useful in defining a continuum of virtual capabilities, ranging from those at the low end that derive from general technology diffusion and the existence of nuclear energy programs to those at the high end that involve conscious decisions to develop or maintain militarily significant nuclear-weapon capabilities.

Pilat, J.F.

1997-08-01T23:59:59.000Z

112

Automatic Testing Tool for OSCAR Using System-level Virtualization  

SciTech Connect (OSTI)

To ensure quality, software development has to include testing mechanisms. OSCAR today supports several Linux distributions and several architectures. In such a context, the release cycle suffers of a important overhead created by the testing and stabilization phase. To address this issue, an approach is to implement a tool for automatic testing. This paper presents such a tool which is based on the OSCAR command line interface. This tool, based on system-level virtualization techniques, creates a virtual cluster to perform the test. This approach has the benefit of not corrupting the system of the physical machine and guarantee that the environment used for testing has not been corrupted before testing.

Vallee, Geoffroy R [ORNL; Naughton, III, Thomas J [ORNL; Bland, Wesley B [ORNL; Scott, Stephen L [ORNL

2007-01-01T23:59:59.000Z

113

Virtual Leadership in Brazil - Virtual Intelligence in Multinational Companies.  

E-Print Network [OSTI]

?? As the technology develops, the communication infrastructure continues to innovate and increase competitiveness. For companies in a country such as Brazil, communicating virtually may… (more)

Wikström, Ida

2014-01-01T23:59:59.000Z

114

Comparative study of micromixing models in transported scalar PDF simulations of turbulent nonpremixed bluff body flames  

SciTech Connect (OSTI)

Numerical simulation results are presented for turbulent jet diffusion flames with various levels of turbulence-chemistry interaction, stabilized behind a bluff body (Sydney Flames HM1-3). Interaction between turbulence and combustion is modeled with the transported joint-scalar PDF approach. The mass density function transport equation is solved in a Lagrangian manner. A second-moment-closure turbulence model is applied to obtain accurate mean flow and turbulent mixing fields. The behavior of two micromixing models is discussed: the Euclidean minimum spanning tree model and the modified Curl coalescence dispersion model. The impact of the micromixing model choice on the results in physical space is small, although some influence becomes visible as the amount of local extinction increases. Scatter plots and profiles of conditional means and variances of thermochemical quantities, conditioned on the mixture fraction, are discussed both within and downstream of the recirculation region. A distinction is made between local extinction and incomplete combustion, based on the CO species mass fraction. The differences in qualitative behavior between the micromixing models are explained and quantitative comparison to experimental data is made. (author)

Merci, Bart [Department of Flow, Heat and Combustion Mechanics, Ghent University-UGent, Ghent (Belgium); Roekaerts, Dirk [Department of Multi-Scale Physics, Delft University of Technology, Delft (Netherlands); Naud, Bertrand [CIEMAT, Madrid (Spain); Pope, Stephen B. [Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY (United States)

2006-07-15T23:59:59.000Z

115

Synergistic flame retardant effect of metal hydroxide and nanoclay in EVA composites  

Science Journals Connector (OSTI)

This study focused on the flame retardancy of ethylene-vinyl acetate copolymer (EVA) in combination with metal hydroxide and nanoclay. Fire tests, such as limiting oxygen index (LOI), flammability (UL-94), cone calorimeter, and smoke density chamber were employed to evaluate the effect of composition variation for the metal hydroxide and the nanoclay in EVA composites. The experimental results showed that when the nanoclay of 1 or 2 weight per cent was substituted for the aluminum hydroxide or magnesium hydroxide in EVA blends, the LOI value was significantly improved while the V-0 rating was maintained. The data obtained from the cone calorimeter test indicated that the peak heat release rate (pk-HRR) is reduced by about 28%–47%. The smoke density data (maximal smoke density, Dm) showed a reduction by about 16%–25%. The thermogravimetric analysis (TGA) data also showed that the nanoclay increased the thermal stability and char residue of the EVA samples. Hence, it is suggested that the metal oxide layer on the burning surface is reinforced by the formation of silicate layer, which is both structured and compacted and acts as the insulation, and the newly formed layer responds to the synergistic effect of flame retardancy as well as smoke suppression observed in the EVA blends.

Ynh-Yue Yen; Hsin-Ta Wang; Wen-Jen Guo

2012-01-01T23:59:59.000Z

116

Modeling of the formation of short-chain acids in propane flames  

E-Print Network [OSTI]

In order to better understand their potential formation in combustion systems, a detailed kinetic mechanism for the formation of short-chain monocarboxylic acids, formic (HCOOH), acetic (CH3COOH), propionic (C2H5COOH) and propenic (C2H3COOH)) acids, has been developed. Simulations of lean (equivalence ratios from 0.9 to 0.48) laminar premixed flames of propane stabilized at atmospheric pressure with nitrogen as diluent have been performed. It was found that amounts up to 25 ppm of acetic acid, 15 ppm of formic acid and 1 ppm of C3 acid can be formed for some positions in the flames. Simulations showed that the more abundant C3 acid formed is propenic acid. A quite acceptable agreement has been obtained with the scarce results from the literature concerning oxygenated compounds, including aldehydes (CH2O, CH3CHO) and acids. A reaction pathways analysis demonstrated that each acid is mainly derived from the aldehyde of similar structure.

Battin-Leclerc, Frédérique; Jaffrezo, J L; Legrand, M

2009-01-01T23:59:59.000Z

117

Investigation of H2 Concentration and Combustion Instability Effects on the Kinetics of Strained Syngas Flames  

SciTech Connect (OSTI)

The flame extinction limits of syngas (H{sub 2}-CO) flames were measured using a twin-flame-counter-flow burner. Plots of Extinction limits vs. global stretch rates were generated at different mixture compositions and an extrapolation method was used to calculate the flame extinction limit corresponding to an experimentally unattainable zero-stretch condition. The zero-stretch extinction limit of H{sub 2}-CO mixtures decreases (from rich to lean) with the increase in H{sub 2} concentration in the mixture. The average difference between the measured flame extinction limit and the Le Chatelier's calculation is around {approx} 7%. The measured OH{sup -} chemiluminescent data indicates that regardless of mixture compositions the OH radical concentration reduces (within the experimental uncertainties) to an extinction value prior to the flame extinction. Flame extinction limits of H{sub 2}-CO mixtures measured in a flat-flame burner configuration also show a similar relation. Additionally, the measured laminar flame velocity close to the extinction indicates that regardless of fuel composition the premixed flame of hydrogen fuel blends extinguishes when the mixture laminar flame velocity falls below a critical value. The critical laminar flame velocity at extinction for H{sub 2}-CO premixed flames (measured in the flat flame burner configuration) is found to be 3.77({+-}0.38) cm/s. An externally perturbed H{sub 2}-CO twin flame was not experimentally achievable for the mixture conditions used in the present investigation. A slightest perturbation in the flow-field distorts the H{sub 2}-CO twin-flame. The flame becomes highly unstable with the introduction of an externally excited flow oscillation.

Ahsan R. Choudhuri

2006-08-07T23:59:59.000Z

118

Virtual Machine in Automation Projects.  

E-Print Network [OSTI]

?? Virtual machine, as an engineering tool, has recently been introduced into automation projects in Tetra Pak Processing System AB. The goal of this paper… (more)

Xing, Xiaoyuan

2010-01-01T23:59:59.000Z

119

Stereo Panorama Personal Virtual Environment  

Science Journals Connector (OSTI)

We describe a personal panoramic virtual environment system with an autostereoscopic display. We discuss swing panoramic image capture, automatic disparity control, spatial sampling,...

Wang, Chiao; Garagate, Jui; Sawchuk, Alexander A

120

Combustor oscillation pressure stabilizer  

SciTech Connect (OSTI)

In accordance with the objective of the present invention, the active control of unsteady combustion induced oscillations in a combustion chamber fired by a suitable fuel and oxidizer mixture, such as a hydrocarbon fuel and air mixture, is provided by restructuring and moving the position of the main flame front and thereby increasing the transport time and displacing the pressure wave further away from the in-phase relationship with the periodic heat release. The restructuring and repositioning of the main flame are achieved by utilizing a pilot flame which is pulsed at a predetermined frequency corresponding to less than about one-half the frequency of the combustion oscillation frequency with the duration of each pulse being sufficient to produce adequate secondary thermal energy to restructure the main flame and thereby decouple the heat release from the acoustic coupling so as to lead to a reduction in the dynamic pressure amplitude. The pulsating pilot flame produces a relatively small and intermittently existing flame front in the combustion zone that is separate from the oscillating main flame front but which provides the thermal energy necessary to effectively reposition the location of the oscillating main flame front out of the region in the combustion zone where the acoustic coupling can occur with the main flame and thereby effectively altering the oscillation-causing phase relationship with the heat of combustion.

Gemmen, R.S.; Richards, G.A.; Yip, M.T.J.; Robey, E.; Cully, S.R.; Addis, R.E.

1996-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Effect of Nitrogen Additives on Flame Retardant Action of Tributyl Phosphate: Phosphorus – Nitrogen Synergism  

SciTech Connect (OSTI)

The effect of nitrogen additives like urea, guanidine carbonate and melamine formaldehyde on the flame retardant efficacy of tributyl phosphate (TBP) has been investigated. From the LOI tests on treated cotton it is clear that the nitrogen additives have synergistic action. Estimation of activation energy of decomposition of treated cotton indicated that nitrogen additives enhance the thermal stability during the burning process. SEM pictures of chars formed after LOI test showed the formation of protective polymeric coating on the surface. The surface of chars formed were evaluated using FTIR-ATR and XPS analysis which showed that the coating was composed of Phosphorus-Nitrogen-Oxygen containing species. Formation of this coating during the burning process could lead to the synergistic interaction of phosphorus and nitrogen. Based on the experimental data we have further proposed several reaction mechanisms which could contribute to synergistic action and formation of protective coating on the surface of char.

Gaan, Sabyasachi; Sun, Gang; Hutches, Katherine; Engelhard, Mark H.

2008-01-01T23:59:59.000Z

122

Turbulent flame speed for syngas at gas turbine relevant conditions  

Science Journals Connector (OSTI)

Modifications of conventional natural-gas-fired burners for operation with syngas fuels using lean premixed combustion is challenging due to the different physicochemical properties of the two fuels. A key differentiating parameter is the turbulent flame velocity, ST, commonly expressed as its ratio to the laminar flame speed, SL. This paper reports an experimental investigation of premixed syngas combustion at gas turbine like conditions, with emphasis on the determination of ST/SL derived as global fuel consumption per unit time. Experiments at pressures up to 2.0 MPa, inlet temperatures and velocities up to 773 K and 150 m/s, respectively, and turbulence intensity to laminar flame speed ratios, u?/SL, exceeding 100 are presented for the first time. Comparisons between different syngas mixtures and methane clearly show much higher ST/SL for the former fuel. It is shown that ST/SL is strongly dependent on preferential diffusive-thermal (PDT) effects, co-acting with hydrodynamic effects, even for very high u?/SL. ST/SL increases with rising hydrogen content in the fuel mixture and with increasing pressure. A correlation for ST/SL valid for all investigated fuel mixtures, including methane, is proposed in terms of turbulence properties (turbulence intensity and integral length scale), combustion properties (laminar flame speed and laminar flame thickness) and operating conditions (pressure and inlet temperature). The correlation captures effects of preferential diffusive-thermal and hydrodynamic instabilities.

S. Daniele; P. Jansohn; J. Mantzaras; K. Boulouchos

2011-01-01T23:59:59.000Z

123

Grid resolution effects on LES of a piloted methane-air flame K. A. Kemenov  

E-Print Network [OSTI]

not only for canonical geome- tries like laboratory jet flames but also for complex ones like gas-turbine in the flame shows some residual grid dependence. Introduction Large Eddy Simulation (LES) has proved

124

Layer-by-Layer Nanocoatings with Flame Retardant and Oxygen Barrier Properties: Moving Toward Renewable Systems  

E-Print Network [OSTI]

) clay to create a renewable flame retardant nanocoating for polyurethane foam. This coating system completely stops the melting of a flexible polyurethane foam when exposed to direct flame from a butane torch, with just 10 bilayers (~ 30 nm thick...

Laufer, Galina 1985-

2012-10-23T23:59:59.000Z

125

The fabrication and properties characterization of wood-based flame retardant composites  

Science Journals Connector (OSTI)

Wood-based flame retardant composites were fabricated based on vacuum-pressure impregnating method after high intensive microwave pretreatment. The effects of ammonium polyphosphate (APP) and modified nano-zinc borate (nZB) addition on flame-retardation ...

Xia He, Xianjun Li, Zhu Zhong, Yongli Yan, Qunying Mou, Chunhua Yao, Chun Wang

2014-01-01T23:59:59.000Z

126

E-Print Network 3.0 - aerosol flame deposition Sample Search...  

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

search results for: aerosol flame deposition Page: << < 1 2 3 4 5 > >> 1 Flame aerosol nano-technology has been developed to preparation of thin and defect-free porous membrane...

127

Virtual stationary timed automata for mobile networks  

E-Print Network [OSTI]

In this thesis, we formally define a programming abstraction for mobile networks called the Virtual Stationary Automata programming layer, consisting of real mobile clients, virtual timed I/O automata called virtual ...

Nolte, Tina Ann, 1979-

2009-01-01T23:59:59.000Z

128

Virtual Science Fair | Department of Energy  

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

Virtual Science Fair Virtual Science Fair The Bioenergy Technology Office (BETO) is hosting a national virtual science fair that engages 9th-12th grade students in learning about...

129

Uncertainty and Virtual Particles  

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

Incertidumbre y partículas virtuales Incertidumbre y partículas virtuales Volver Principal ESTOY PERDIDO!!! El principio de incerteza de Heisenberg: En 1927, Heisenberg enunció una propiedad fundamental de la mecánica cuántica que dice que es imposible medir EN FORMA EXACTA AMBOS, la posición de una partícula y su ímpetu. Cuanto mayor sea la precisión con que determinamos una, menos sabremos de la otra. Este es el llamado Principio de incerteza de Heisenberg. La relación matemática que lo expresa es: Significa que la incertidumbre en la posición (x), multiplicada por la incertidumbre en el momento (p), es mayor o igual que una constante (h-barra dividido por dos.) Este principio puede también ser escrito en términos de energía y tiempo: Significa que la incertidumbre en la energía de una partícula

130

Virtual Optical Comparator  

SciTech Connect (OSTI)

The Virtual Optical Comparator, VOC, was conceived as a result of the limitations of conventional optical comparators and vision systems. Piece part designs for mechanisms have started to include precision features on the face of parts that must be viewed using a reflected image rather than a profile shadow. The VOC concept uses a computer generated overlay and a digital camera to measure features on a video screen. The advantage of this system is superior edge detection compared to traditional systems. No vinyl charts are procured or inspected. The part size and expensive fixtures are no longer a concern because of the range of the X-Y table of the Virtual Optical Comparator. Product redesigns require only changes to the CAD image overlays; new vinyl charts are not required. The inspection process is more ergonomic by allowing the operator to view the part sitting at a desk rather than standing over a 30 inch screen. The procurement cost for the VOC will be less than a traditional comparator with a much smaller footprint with less maintenance and energy requirements.

Thompson, Greg

2008-10-20T23:59:59.000Z

131

Metrological tool for the characterization of flame fronts based on the coupling of heat  

E-Print Network [OSTI]

° flame inclination angle due to wind [ ]th i W theoretical radiative heat flux received by the ith target

Boyer, Edmond

132

Engineering Virtualized Services Elvira Albert  

E-Print Network [OSTI]

Engineering Virtualized Services Elvira Albert Complutense University of Madrid, Spain elvira project FP7-610582 ENVISAGE: Engineering Virtualized Services (http://www.envisage-project.eu). level of an application-level service at the expense of potentially changing its cost profile. In traditional engineering

Johnsen, Einar Broch

133

Flame Synthesis of One-Dimensional Metal Oxide Nanomaterials  

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

Synthesis of One-Dimensional Metal Oxide Nanomaterials Synthesis of One-Dimensional Metal Oxide Nanomaterials Alexei V. Saveliev Dept. of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695, USA Robust, scalable, and energy efficient methods of nanomaterial synthesis are needed to meet the demands of current and potential applications. Flames have been successfully applied for the synthesis of metal oxide and ceramic nanopowders largely composed of spherical particles and their aggregates. In recent years, premixed and diffusion flames have been employed for the synthesis of 1-D carbon nanoforms such as carbon fibers and carbon nanotubes. The extension of flame methods to gas phase and solid support synthesis of 1-D inorganic nanoforms is of great interest and significance. This talk presents

134

Radiation-Driven Flame Spread Over Thermally-Thick Fuels in Quiescent Microgravity Environments  

E-Print Network [OSTI]

Radiation-Driven Flame Spread Over Thermally-Thick Fuels in Quiescent Microgravity Environments-non-premixed, flame-spread Submitted to Twenty-Ninth International Symposium on Combustion, Sapporo, Japan, July 21 ­ July 26, 2002. #12;Radiation-Driven Flame Spread Over Thermally-Thick Fuels in Quiescent Microgravity

135

Prediction of oxy-coal flame stand-off using high-fidelity thermochemical models  

E-Print Network [OSTI]

Prediction of oxy-coal flame stand-off using high-fidelity thermochemical models and the one Abstract An Eulerian one-dimensional turbulence (ODT) model is applied to simulate oxy-coal combustion temperature and mixing rate on oxy-coal flame is simulated and discussed where flame stand-off is used

136

Turbulent Oxygen Flames in Type Ia Supernovae A. J. Aspden1  

E-Print Network [OSTI]

Turbulent Oxygen Flames in Type Ia Supernovae A. J. Aspden1 , J. B. Bell1 , and S. E. Woosley2 oxygen flames. The two aims of the paper are to examine the response of the inductive oxygen flame to intense levels of turbulence, and to explore the possibility of transition to detonation in the oxygen

137

Real Time Flame Monitoring of Gasifier Burner and Injectors  

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

Real Time Flame Monitoring of Gasifier Real Time Flame Monitoring of Gasifier Burner and Injectors Background The Gasification Technologies Program at the National Energy Technology Laboratory (NETL) supports research and development (R&D) in the area of gasification-a process whereby carbon-based materials (feedstocks) such as coal are converted into synthesis gas (syngas), which is separated into hydrogen (H 2 ) and carbon dioxide (CO 2 ) gas streams in a combustion turbine-generator as a way to generate clean electricity while

138

Oxy-fuel Combustion of Ethanol in Premixed Flames  

Science Journals Connector (OSTI)

(11-14) First, measurements using a heat flux setup for liquid fuels were studied on ethanol + air combustion. ... The heat flux method builds on the principle that heat is transferred to the unburnt gas, cooling the plate, while heat transfer from the flame heats the plate. ... A detailed kinetic scheme was compiled using known data on EtOH kinetics and is self-consistent in that it closely predicts laminar flame speed of EtOH, CH4, MeOH, and C2-hydrocarbons. ...

Jenny D. Nauclér; Moah Christensen; Elna J. K. Nilsson; Alexander A. Konnov

2012-06-19T23:59:59.000Z

139

Experimental study of industrial gas turbine flames including quantification of pressure influence on flow field, fuel/air premixing and flame shape  

Science Journals Connector (OSTI)

Abstract A commercial swirl burner for industrial gas turbine combustors was equipped with an optically accessible combustion chamber and installed in a high-pressure test-rig. Several premixed natural gas/air flames at pressures between 3 and 6 bar and thermal powers of up to 1 MW were studied by using a variety of measurement techniques. These include particle image velocimetry (PIV) for the investigation of the flow field, one-dimensional laser Raman scattering for the determination of the joint probability density functions of major species concentrations, mixture fraction and temperature, planar laser induced fluorescence (PLIF) of OH for the visualization of the flame front, chemiluminescence measurements of OH* for determining the lift-off height and size of the flame and acoustic recordings. The results give insights into important flame properties like the flow field structure, the premixing quality and the turbulence–flame interaction as well as their dependency on operating parameters like pressure, inflow velocity and equivalence ratio. The 1D Raman measurements yielded information about the gradients and variation of the mixture fraction and the quality of the fuel/air mixing, as well as the reaction progress. The OH PLIF images showed that the flame was located between the inflow of fresh gas and the recirculated combustion products. The flame front structures varied significantly with Reynolds number from wrinkled flame fronts to fragmented and strongly corrugated flame fronts. All results are combined in one database that can be used for the validation of numerical simulations.

Ulrich Stopper; Wolfgang Meier; Rajesh Sadanandan; Michael Stöhr; Manfred Aigner; Ghenadie Bulat

2013-01-01T23:59:59.000Z

140

Small-scale Interaction of Turbulence with Thermonuclear Flames in Type Ia Supernovae  

E-Print Network [OSTI]

Microscopic turbulence-flame interactions of thermonuclear fusion flames occuring in Type Ia Supernovae were studied by means of incompressible direct numerical simulations with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its Prandtl number, Pr << 1, and laminar flame speed, S_L. We find that if S_L ~ u', where u' is the rms amplitude of turbulent velocity fluctuations, the local flame propagation speed does not significantly deviate from S_L even in the presence of velocity fluctuations on scales below the laminar flame thickness. This result is interpreted in the context of subgrid-scale modeling of supernova explosions and the mechanism for deflagration-detonation-transitions.

J. C. Niemeyer; W. K. Bushe; G. R. Ruetsch

1999-05-07T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

NETL: Investigation on Flame Characteristics and Burner Operability Issues  

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

Investigation on Flame Characteristics and Burner Operability Issues of Oxy-Fuel Combustion Investigation on Flame Characteristics and Burner Operability Issues of Oxy-Fuel Combustion Project No.: DE-FE0002402 NETL has partnered with the University of Texas at El Paso (UTEP) to investigate the characteristics of oxy-fuel flames and assess their impact on the operability of oxy-fuel combustion systems. The examination of fundamental flame characteristics data and related burner operability parameters are essential for designing and developing oxy-fuel combustion systems for new power plants and retrofitting existing power generation units. In an oxy-fuel system, coal is combusted in an enriched oxygen environment using pure oxygen diluted with recycled CO2 or water vapor (H2O), resulting in a flue stream consisting only of CO2 and H2O (no other co-contaminants) (Figure 1). Oxy-fuel combustion is promising for CCUS applications because water can be condensed out of the CO2/H2O flue stream to produce a relatively pure CO2 end product for capture. Oxy-fuel combustion and subsequent CO2 capture is currently being considered by the DOE's Innovations for Existing Plants Program as having the potential to meet the goal of 90 percent CO2 capture without increasing the cost of electricity more than 35 percent.

142

Ignition and Flame Quenching of Quiescent Fuel Mists  

Science Journals Connector (OSTI)

...Ignition and Flame Quenching of Quiescent Fuel Mists D. R. Ballal A. H. Lefebvre A...the ignition of quiescent multidroplet fuel mists which assumes that chemical reaction...spark, of an adequate concentration of fuel vapour in the ignition zone. From analysis...

1978-01-01T23:59:59.000Z

143

Flame Contact, a New Departure in Water Heating1  

Science Journals Connector (OSTI)

... paper. We can, by a modification of this experiment, measure the depth of the flameless space, as the copper, if placed against the paper before it has time to ... gum, which is liable to swell and force the paper past the limit of the flameless space, and also to allow the paste to dry before applying the flame, as ...

1886-07-08T23:59:59.000Z

144

Measurements of Laminar Flame Velocity for Components of Natural Gas  

E-Print Network [OSTI]

gas in combustion engines and power generation systems. The main hydrocarbon included in natural gas, BP 20451, 1 Rue Grandville, 54001 Nancy, France 2 Division of Combustion Physics, Lund University performed by the heat flux method using a newly built flat flame adiabatic burner at atmospheric pressure

Paris-Sud XI, Université de

145

Formation mechanism for polycyclic aromatic hydrocarbons in methane flames  

E-Print Network [OSTI]

aromatic hydrocarbons PAHs up to 788 amu (C64H20) were detected in the combustion gases. Only the most applications including heating systems and gas turbines for electric power generation.62­64 The combustionFormation mechanism for polycyclic aromatic hydrocarbons in methane flames K. Siegmanna) Swiss

Sattler, Klaus

146

Treating Unresolvable Flame Physics in Simulations of Thermonuclear Supernovae  

Science Journals Connector (OSTI)

Due to the small width of the subsonic burning front (flame) in thermonuclear supernovae, micrometers to centimeters, and the influence of turbulence, which adds structure to this front on a broad range of scales, it won't be possible in the foreseeable ... Keywords: Computational astrophysics, combustion, turbulence

Dean M. Townsley

2009-03-01T23:59:59.000Z

147

Paper # A02 Topic: Laminar Flames US Combustion Meeting  

E-Print Network [OSTI]

been focused on synthetic fuel gas (syngas) combustion. Syngas is derived from coal throughPaper # A02 Topic: Laminar Flames 1 5th US Combustion Meeting Organized by the Western States Section of the Combustion Institute and Hosted by the University of California at San Diego March 25

Seitzman, Jerry M.

148

Analyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames  

E-Print Network [OSTI]

- bly burning ultra-lean hydrogen-air fuel mixtures. Such burners could, for example, be used as oneAnalyzing and Tracking Burning Structures in Lean Premixed Hydrogen Flames P.-T. Bremer1, G. Weber2 of the temporal behavior. We demonstrate our approach by analyzing three numerical simulations of lean hydrogen

149

Virtual humans: back to the future  

Science Journals Connector (OSTI)

This paper essentially tries to examine all the roles that Virtual Humans can play in empowering human expression, and the research challenges we have to face to make this possible. It starts with a short history of Virtual Humans and how we contribute ... Keywords: computer animation, virtual humans, virtual reality

Nadia Magnenat Thalmann; Daniel Thalmann

2012-05-01T23:59:59.000Z

150

Real Time Flame Monitoring of Gasifier and Injectors  

SciTech Connect (OSTI)

This project is a multistage effort with the final goal to develop a practical and reliable nonintrusive gasifier injector monitor to assess burner wear and need for replacement. The project team included the National Energy Technology Laboratory (NETL), Gas Technology Institute (GTI), North Carolina State University, and ConocoPhillips. This report presents the results of the sensor development and testing initially at GTI combustion laboratory with natural gas flames, then at the Canada Energy Technology Center (CANMET), Canada in the atmospheric coal combustor as well as in the pilot scale pressurized entrained flow gasifier, and finally the sensor capabilities were demonstrated at the Pratt and Whitney Rocketdyne (PWR) Gasifier and the Wabash River Repowering plant located in West Terre Haute, IN. The initial tests demonstrated that GTI gasifier sensor technology was capable of detecting shape and rich/lean properties of natural gas air/oxygen enriched air flames. The following testing at the Vertical Combustor Research Facility (VCRF) was a logical transition step from the atmospheric natural gas flames to pressurized coal gasification environment. The results of testing with atmospheric coal flames showed that light emitted by excited OH* and CH* radicals in coal/air flames can be detected and quantified. The maximum emission intensities of OH*, CH*, and black body (char combustion) occur at different axial positions along the flame length. Therefore, the excitation rates of CH* and OH* are distinct at different stages of coal combustion and can be utilized to identify and characterize processes which occur during coal combustion such as devolatilization, char heating and burning. To accomplish the goals set for Tasks 4 and 5, GTI utilized the CANMET Pressurized Entrained Flow Gasifier (PEFG). The testing parameters of the PEFG were selected to simulate optimum gasifier operation as well as gasifier conditions normally resulting from improper operation or failed gasifier injectors. The sensor developed under previous tasks was used to assess the spectroscopic characteristics of the gasifier flame. The obtained spectral data were successfully translated into flame temperature measurements. It was also demonstrated that the reduced spectral data could be very well correlated with very important gasification process parameters such as the air/fuel and water/fuel ratio. Any of these parameters (temperature, air/fuel, and water/fuel) is sufficient to assess burner wear; however, the tested sensor was capable of monitoring all three of them plus the flame shape as functions of burner wear. This will likely be a very powerful tool which should enable significant improvements in gasifier efficiency, reliability, and availability. The sensor technology was presented to the projectâ??s industrial partner (ConocoPhillips). The partner expressed its strong interest in continuing to participate in the field validation phase of GTI's Flame Monitor Project. Finally the sensor was tested in the PWR (Pratt & Whitney Rocketdyne) gasification plant located at GTIâ??s research campus and at the ConocoPhillips industrial scale gasifier at Wabash River Indiana. The field trials of the GTI Gasifier sensor modified to withstand high temperature and pressure corrosive atmosphere of the industrial entrain flow gasifier. The project team successfully demonstrated the Gasifier Sensor system ability to monitor gasifier interior temperature maintaining unobstructed optical access for in excess of six week without any maintenance. The sensor examination upon completion of the trial revealed that the system did not sustain any damage and required minor cleanup of the optics.

Zelepouga, Serguei; Saveliev, Alexei

2011-12-31T23:59:59.000Z

151

Virtual gap dielectric wall accelerator  

DOE Patents [OSTI]

A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

2013-11-05T23:59:59.000Z

152

System Management Software for Virtual Environments  

SciTech Connect (OSTI)

Recently there has been an increased interest in the use of system-level virtualization using mature solutions such as Xen, QEMU, or VMWare. These virtualization platforms are being used in distributed and parallel environments including high performance computing. The use of virtual machines within such environments introduces new challenges to system management. These include tedious tasks such as deploying para-virtualized host operating systems to support virtual machine execution or virtual overlay networks to connect these virtual machines. Additionally, there is the problem of machine definition and deployment, which is complicated by differentiation in the underlying virtualization technology. This paper discusses tools for the deployment and management of both host operating systems and virtual machines in clusters. We begin with an overview of system-level virtualization and move on to a description of tools that we have developed to aid with these environments. These tools extend prior work in the area of cluster installation, configuration and management.

Vallee, Geoffroy R [ORNL; Naughton, III, Thomas J [ORNL; Scott, Stephen L [ORNL

2007-01-01T23:59:59.000Z

153

THE EFFECTS OF FLAME TEMPERATURE, PARTICLE SIZE AND EUROPIUM DOPING CONCENTRATION ON THE PROPERTIES OF Y2O3:EU PARTICLES FORMED IN A FLAME AEROSOL PROCESS  

E-Print Network [OSTI]

ix LIST OF FIGURES FIGURE Page 1 Schematic of flame spray pyrolysis apparatus... 2 O 3 :Eu 9, 10 . A number of methods may be used to synthesize Y 2 O 3 :Eu particles, including colloidal methods 11-13 , combustion in fuel-oxidizer mixture 14 , evaporation? condensation 15, 16 , furnace spray pyrolysis 17 . Flame aerosol...

Yim, Hoon

2010-07-14T23:59:59.000Z

154

Reti attive di distribuzione: le applicazioni Virtual Power Plant e Virtual Utility.  

E-Print Network [OSTI]

??Il presente lavoro si occupa di nuove applicazioni per la gestione e l’ottimizzazione di risorse distribuite, così dette Virtual Power Plant (VPP) o Virtual Utility… (more)

Baroncelli, Paolo

2005-01-01T23:59:59.000Z

155

Virtual Oxygen Sensor for Innovative NOx and PM Emission Control...  

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

Virtual Oxygen Sensor for Innovative NOx and PM Emission Control Technologies Virtual Oxygen Sensor for Innovative NOx and PM Emission Control Technologies A virtual O2 sensor for...

156

Real Time Flame Monitoring of Gasifier Burner and Injectors  

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

8 8 Gasification Technologies contacts Gary J. stiegel Gasification Technology Manager National Energy Technology Laboratory 626 Cochrans Mill Road P.O. Box 10940 Pittsburgh, PA 15236 412-386-4499 gary.stiegel@netl.doe.gov Jenny tennant Project Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880 Morgantown, WV 26507 304-285-4830 jenny.tennant@netl.doe.gov David Rue Principal Investigator Gas Technology Institute 1700 South Mount Prospect Road Des Plaines, IL 60018 847-768-0508 david.rue@gastechnology.org Real Time Flame moniToRing oF gasiFieR BuRneR and injecToRs Description Combustion scientists and engineers have studied radiant emissions of various flames for many years. For some time, technologists have understood the rich potential for

157

A model of virtual interference  

E-Print Network [OSTI]

We set up an experiment with two independent laser beams that cross at a small angle, spatially separate, and end at detectors in front of each beam. The setup allows us to obtain maximum path or which-way information, K=1. However, when we scan a thin wire across the beam intersection the which-way information drops to K=0.985. The thin wire serves to verify the presence of an interference pattern with visibility, V=0.833, at the beam intersection. Our results appear to be in conflict with the complementarity inequality, V^2+K^2 smaller or equal to 1. We introduce a model that describes a virtual interference pattern. We resolve our paradoxical findings by proposing that the complementarity inequality does not apply to virtual interference patterns but only to physically real ones. We find that the interference pattern in our setup is virtual.

Flores, Eduardo V; Scaturro, Jeffrey

2014-01-01T23:59:59.000Z

158

Efficient Checkpointing of Virtual Machines using Virtual Machine Introspection  

SciTech Connect (OSTI)

Cloud Computing environments rely heavily on system-level virtualization. This is due to the inherent benefits of virtualization including fault tolerance through checkpoint/restart (C/R) mechanisms. Because clouds are the abstraction of large data centers and large data centers have a higher potential for failure, it is imperative that a C/R mechanism for such an environment provide minimal latency as well as a small checkpoint file size. Recently, there has been much research into C/R with respect to virtual machines (VM) providing excellent solutions to reduce either checkpoint latency or checkpoint file size. However, these approaches do not provide both. This paper presents a method of checkpointing VMs by utilizing virtual machine introspection (VMI). Through the usage of VMI, we are able to determine which pages of memory within the guest are used or free and are better able to reduce the amount of pages written to disk during a checkpoint. We have validated this work by using various benchmarks to measure the latency along with the checkpoint size. With respect to checkpoint file size, our approach results in file sizes within 24% or less of the actual used memory within the guest. Additionally, the checkpoint latency of our approach is up to 52% faster than KVM s default method.

Aderholdt, Ferrol [Tennessee Technological University] [Tennessee Technological University; Han, Fang [Tennessee Technological University] [Tennessee Technological University; Scott, Stephen L [ORNL] [ORNL; Naughton, III, Thomas J [ORNL

2014-01-01T23:59:59.000Z

159

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

SciTech Connect (OSTI)

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.

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

2013-09-30T23:59:59.000Z

160

E-Print Network 3.0 - atomic-absorption flame photometry Sample...  

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

Search Powered by Explorit Topic List Advanced Search Sample search results for: atomic-absorption flame photometry Page: << < 1 2 3 4 5 > >> 1 MICROCHEMICALJOURNAL33,304-...

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

IGNITION PROCESSES AND FLAME SPREADING IN A GRANULAR SOLID PROPELLANT BED.  

E-Print Network [OSTI]

??Understanding the detailed ignition, flame spreading, and combustion processes inside of a granular solid propellant bed is vital for accurate internal ballistic modeling and development… (more)

Colletti, Alexander

2010-01-01T23:59:59.000Z

162

3D Spectroscopy in the Virtual Observatory: Current Status  

E-Print Network [OSTI]

Three cornerstones for the 3D data support in the Virtual Observatory are: (1) data model to describe them, (2) data access services providing access to fully-reduced datasets, and (3) client applications which can deal with 3D data. Presently all these components became available in the VO. We demonstrate an application of the IVOA Characterisation data model to description of IFU and Fabry-Perot datasets. Two services providing SSA-like access to 3D-spectral data and Characterisation metadata have been implemented by us: ASPID-SR at SAO RAS for accessing IFU and Fabry-Perot data from the Russian 6-m telescope, and the Giraffe Archive at the VO Paris portal for the VLT FLAMES-Giraffe datasets. We have implemented VO Paris Euro3D Client, handling Euro3D FITS format, that interacts with CDS Aladin and ESA VOSpec using PLASTIC to display spatial and spectral cutouts of 3D datasets. Though the prototype we are presenting is yet rather simple, it demonstrates how 3D spectroscopic data can be fully integrated into the VO infrastructure.

Igor Chilingarian; Francois Bonnarel; Mireille Louys; Ivan Zolotukhin; Frederic Royer; Isabelle Jegouzo; Pierre Le Sidaner; Pierre Fernique; Thomas Boch

2007-11-02T23:59:59.000Z

163

Virtual articulation and kinematic abstraction in robotics  

E-Print Network [OSTI]

This thesis presents the theory, implementation, novel applications, and experimental validation of a general-purpose framework for applying virtual modifications to an articulated robot, or virtual articulations. These ...

Vona, Marsette Arthur, 1977-

2009-01-01T23:59:59.000Z

164

Construction of Matlab Circuit Analysis Virtual Laboratory  

Science Journals Connector (OSTI)

The Matlab virtual laboratory was composed of the management ... the CGI interface to link the pilot designed project  would to complete the virtual  simulation. Practice...

Shoucheng Ding

2012-01-01T23:59:59.000Z

165

A Virtual Environment Framework For Software Engineering  

E-Print Network [OSTI]

A Virtual Environment Framework For Software Engineering Stephen E. Dossick Submitted in partial Environment Framework for Software Engineering Stephen E. Dossick The field of Software Engineering, responsible for mapping project artifacts into virtual environment furnishings, and the CHIME Theme Manager

Kaiser, Gail E.

166

LASER STABILIZATION FOR NEAR ZERO NO{sub x} GAS TURBINE COMBUSTION SYSTEMS  

SciTech Connect (OSTI)

Historically, the development of new industrial gas turbines has been primarily driven by the intent to achieve higher efficiency, lower operating costs and lower emissions. Higher efficiency and lower cost is obtained through higher turbine operating temperatures, while reduction in emissions is obtained by extending the lean operating limit of the combustor. However reduction in the lean stability limit of operation is limited greatly by the chemistry of the combustion process and by the occurrence of thermo-acoustic instabilities. Solar Turbines, CFD Research Corporation, and Los Alamos National Laboratory have teamed to advance the technology associated with laser-assisted ignition and flame stabilization, to a level where it could be incorporated onto a gas turbine combustor. The system being developed is expected to enhance the lean stability limit of the swirl stabilized combustion process and assist in reducing combustion oscillations. Such a system has the potential to allow operation at the ultra-lean conditions needed to achieve NO{sub x} emissions below 5 ppm without the need of exhaust treatment or catalytic technologies. The research effort was focused on analytically modeling laser-assisted flame stabilization using advanced CFD techniques, and experimentally demonstrating the technology, using a solid-state laser and low-cost durable optics. A pulsed laser beam was used to generate a plasma pool at strategic locations within the combustor flow field such that the energy from the plasma became an ignition source and helped maintain a flame at ultra lean operating conditions. The periodic plasma generation and decay was used to nullify the fluctuations in the heat release from the flame itself, thus decoupling the heat release from the combustor acoustics and effectively reducing the combustion oscillations. The program was built on an existing technology base and includes: extending LANL's existing laser stabilization experience to a sub-scale combustor rig, performing and validating CFD predictions, and ultimately conducting a full system demonstration in a multi-injector combustion system at Solar Turbines.

Vivek Khanna

2002-09-30T23:59:59.000Z

167

Instructions for Using Virtual Private Network (VPN)  

Broader source: Energy.gov [DOE]

Virtual Private Network (VPN) provides access to network drives and is recommended for use only from a EITS provided laptop.

168

VIRTUAL TRAINING CENTRE FOR SHOE DESIGN: A SAMPLE VIRTUAL TRAINING ENVIRONMENT  

E-Print Network [OSTI]

VIRTUAL TRAINING CENTRE FOR SHOE DESIGN: A SAMPLE VIRTUAL TRAINING ENVIRONMENT Aura Mihai1 , Mehmet@tex.tuiasi.ro Abstract It is a fact that virtual training has become a key issue in training. There are numerous virtual learning and training environments and, in parallel with this, there are various approaches and tools

Aristomenis, Antoniadis

169

Watfactory Virtual Manufacturing Process Varying Inputs  

E-Print Network [OSTI]

with the virtual process: · Allows quick exploration (i.e. during a short course) of process improvement ideasWatfactory Virtual Manufacturing Process Machine 1 Machine 2 Machine 3 Stream 1 Machine B Stream 2 Inputs Can be Set by Stream z19, ..., z24 The Watfactory virtual process simulates a manufacturing

Zhu, Mu

170

3, 126, 2006 Virtual water highway  

E-Print Network [OSTI]

Hydrology and Earth System Sciences Virtual water highway: water use efficiency in global food trade H. Yang the efficiency of the5 resource use embodied in the global virtual water trade from the perspectives of ex virtual water. The results suggest efficiency gains in the global food trade in terms of water resource

Paris-Sud XI, Université de

171

Virtual Observatories A New Era for Astronomy  

E-Print Network [OSTI]

Virtual Observatories A New Era for Astronomy Reinaldo R. de Carvalho DAS-INPE/MCT 2010 Wednesday, April 7, 2010 #12;Virtual Observatories A New Era for Astronomy Reinaldo R. de Carvalho DAS!;#--&$G !!!$ ! ' !"#$%&'&#()*! !!!$#%& !( $ ' !%&$ $ ! (% +#&,&'- .'/0&#,& Wednesday, April 7, 2010 #12;Virtual Observatories A New Era for Astronomy Reinaldo R. de

172

The CloudNets Network Virtualization Architecture  

E-Print Network [OSTI]

Nets Network Virtualization Architecture Johannes Grassler jgrassler@inet.tu-berlin.de 05. Februar, 2014 Johannes Grassler jgrassler@inet.tu-berlin.de The CloudNets Network Virtualization Architecture #12;..... . .... . .... . ..... . .... . .... . .... . ..... . .... . .... . .... . ..... . .... . .... . .... . ..... . .... . ..... . .... . .... . Johannes Grassler jgrassler@inet.tu-berlin.de The CloudNets Network Virtualization Architecture #12

Schmid, Stefan

173

Virtualization in Automotive Embedded Systems  

E-Print Network [OSTI]

W / PSA / Freescale - 3 Mastering complexity of automotive Electrical and Electronics (E/E) Systems #12Virtualization in Automotive Embedded Systems : an Outlook Nicolas Navet, RTaW Bertrand Delord, PSA;© 2010 RTaW / PSA / Freescale - 2 Outline 1. Automotive E/E Systems: mastering complexity 2. Ecosystems

Navet, Nicolas

174

Virtual Control Systems Environment (VCSE)  

SciTech Connect (OSTI)

Will Atkins, a Sandia National Laboratories computer engineer discusses cybersecurity research work for process control systems. Will explains his work on the Virtual Control Systems Environment project to develop a modeling and simulation framework of the U.S. electric grid in order to study and mitigate possible cyberattacks on infrastructure.

Atkins, Will

2012-10-08T23:59:59.000Z

175

Virtual platforms: breaking new grounds  

Science Journals Connector (OSTI)

The case for developing and using virtual platforms (VPs) has now been made. If developers of complex HW/SW systems are not using VPs for their current design, complexity of next generation designs demands for their adoption. In addition, the users of ...

Rainer Leupers; Grant Martin; Roman Plyaskin; Andreas Herkersdorf; Frank Schirrmeister; Tim Kogel; Martin Vaupel

2012-03-01T23:59:59.000Z

176

Virtual Control Systems Environment (VCSE)  

ScienceCinema (OSTI)

Will Atkins, a Sandia National Laboratories computer engineer discusses cybersecurity research work for process control systems. Will explains his work on the Virtual Control Systems Environment project to develop a modeling and simulation framework of the U.S. electric grid in order to study and mitigate possible cyberattacks on infrastructure.

Atkins, Will

2014-02-26T23:59:59.000Z

177

Spin Stability  

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

Stability Stability of Asymmetrically Charged Plasma Dust I. H. Hutchinson Plasma Science and Fusion Center Massachusetts Institute of Technology, Cambridge, MA, USA Recently it has been reported that, under some circumstances, dust particles sus- pended in the sheath edge are observed to spin [1, 2, 3]. The present paper shows that there is a natural electrostatic mechanism that should cause even perfectly spherical par- ticles in a perfectly irrotational, magnetic-field-free flowing plasma to spin. The stability criterion and the final spin state are obtained[4]. When the particle is made of an insulating material, it can support potential dif- ferences around its surface. In the limit of zero conductivity, and ignoring all charging effects other than electron or ion collection, the surface charge density accumulates in such a way as to bring the local electric current density to zero.

178

Laser Stabilization  

SciTech Connect (OSTI)

This book chapter covers the basics of the field of stabilizing lasers to optical frequency references such as optical cavities and molecular transitions via the application of servo control systems. These discussions are given with reference to the real-life frequency metrology experienced in Hall-Labs (now Ye-Labs), JILA, University of Colorado. The subjects covered include: the basics of control system stability, a discussion of both the theoretical and experimental limitations, an outline of optical cavity susceptibility to environmental noise, and a brief introduction to the use and limitations of molecular transitions as frequency references.

Hall, John L.; Taubman, Matthew S.; Ye, Jun

2010-01-01T23:59:59.000Z

179

Effects of Combustor Geometry on the Flowfields and Flame Properties of A  

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

Effects of Combustor Geometry on the Flowfields and Flame Properties of A Effects of Combustor Geometry on the Flowfields and Flame Properties of A Low-Swirl Injector Title Effects of Combustor Geometry on the Flowfields and Flame Properties of A Low-Swirl Injector Publication Type Journal Article Year of Publication 2008 Authors Cheng, Robert K., and David Littlejohn Journal Proceedings of the Combustion Institute Type of Article Conference Paper Abstract The Low-swirl injector (LSI) is a novel dry-low NOx combustion method that is being developed for gas turbines to burn a variety of gaseous fuels including natural gas, low-Btu fuels, syngases and hydrogen. Its basic principle is described by a top level analytical model that relates the flame position to the flowfield similarity parameters and the turbulent flame speed correlation. The model was based on experimental measurements in open laboratory flames. It has been useful for guiding hardware development. As the LSI is being adapted to different engine configurations, one open question is how the combustor geometry and size affect its basic operating principle. The objective of this paper is to investigate these effects by conducting Particle Image Velocimetry (PIV) measurements in open and enclosed flames produced by a 6.35 cm diameter LSI using two quartz cylinders of 15.5 and 20 cm diameter to simulate the combustor casing. Results from 18 methane-air flames show that the enclosures do not alter the flame properties or the nearfield flow structures. The differences occur mostly in the farfield where the tighter enclosure deters the formation of a weak recirculation zone. The enclosure effects on hydrogen and hydrogen-methane flames were studies using the 20 cm cylinder. The results show that the outer recirculation zone generated at the corner of the dump plane promotes the formation of attached flames. However, the properties and nearfield flow features of the attached flames are similar to those of the lifted flames. At higher stoichiometries, the attached flame collapses to form a compact disc shaped flame that has very different flowfield structures. These results show that the enclosure effects on the LSI are strongly coupled to the fuel type and dump plane geometry but are less dependent on the enclosure size. These observations will provide the basis for developing computational methods that can be used as design tools for LSI adaptation

180

Effects of fuel type and equivalence ratios on the flickering of triple flames  

SciTech Connect (OSTI)

An experimental study has been conducted in axisymmetric, co-flowing triple flames with different equivalence ratios of the inner and outer reactant streams (2<{phi}{sub in}<3 and 0{<=}{phi}{sub out}<0.7). Different fuel combinations, like propane/propane, propane/methane or methane/methane in the inner and outer streams respectively, have been used in the experiments. The structures of the triple flames have been compared for the different fuel combinations and equivalence ratios. The conditions under which triple flames exhibit oscillation have been identified. During the oscillation, the non-premixed flame and the outer lean premixed flame flicker strongly, while the inner rich premixed flame remains more or less stable. The flickering frequency has been evaluated through image processing and fast Fourier transform (FFT) of the average pixel intensity of the image frames. It is observed that, for all the fuel combinations, the frequency decreases with the increase in the outer equivalence ratio, while it is relatively invariant with the change in the inner equivalence ratio. However, an increase in the inner equivalence ratio affects the structure of the flame by increasing the heights of the inner premixed flame and non-premixed flame and also enlarges the yellow soot-laden zone at the tip of the inner flame. A scaling analysis of the oscillating flames has been performed based on the measured parameters, which show a variation of Strouhal number (St) with Richardson number (Ri) as St {proportional_to} Ri{sup 0.5}. The fuel type is found to have no influence on this correlation. (author)

Sahu, K.B.; Kundu, A.; Ganguly, R.; Datta, A. [Department of Power Engineering, Jadavpur University, Salt Lake Campus, Kolkata 700098 (India)

2009-02-15T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Dynamic stability, blowoff, and flame characteristics of oxy-fuel combustion  

E-Print Network [OSTI]

Oxy-fuel combustion is a promising technology to implement carbon capture and sequestration for energy conversion to electricity in power plants that burn fossil fuels. In oxy-fuel combustion, air separation is used to ...

Shroll, Andrew Philip

2011-01-01T23:59:59.000Z

182

Supersonic Cavity Flame Stabilization Studies using a multivariate quadrature based moment method  

E-Print Network [OSTI]

Predictive models for supersonic combustion will provide a reliable and inexpensive pathway for scramjet

Raman, Venkat

183

Dimpled/grooved face on a fuel injection nozzle body for flame stabilization and related method  

DOE Patents [OSTI]

A fuel injection head for a fuel nozzle used in a gas turbine combustor includes a substantially hollow body formed with an upstream end face, a downstream end face and a peripheral wall extending therebetween. A plurality of pre-mix tubes or passages extend axially through the hollow body with inlets at the upstream end face and outlets at the downstream end face. An exterior surface of the downstream end face is formed with three-dimensional surface features that increase a total surface area of the exterior surface as compared to a substantially flat, planar downstream end face.

Uhm, Jong Ho; Johnson, Thomas Edward; Kim, Kwanwoo; Zuo, Baifang

2013-08-20T23:59:59.000Z

184

Simulation of Nitrogen Emissions in a Premixed Hydrogen Flame Stabilized on a Low Swirl Burner  

E-Print Network [OSTI]

of fuels such as pure hydrogen and hydrogen-seeded hydrocarbon mixtures. However, many hydrogen-rich fuels in the context of a laboratory-scale low swirl burner fueled with a lean hydrogen-air mixture at atmospheric of burning lean hydrogen or hydrogen-enriched lean hydrocar- bon fuels (e.g., [2­5]). For these fuels

Bell, John B.

185

Oxy-coal combustion: stability of coaxial pulverized coal flames in O2/CO2 environments.  

E-Print Network [OSTI]

??Oxy-coal combustion, in which air is replaced by an O2/ CO2 mixture, is one of the few technologies that may allow CO2 capture and sequestration… (more)

Zhang, Jingwei

2010-01-01T23:59:59.000Z

186

Making a Low-Cost Soda Can Ethanol Burner for Out-of-Laboratory Flame Test Demonstrations and Experiments  

Science Journals Connector (OSTI)

Making a Low-Cost Soda Can Ethanol Burner for Out-of-Laboratory Flame Test Demonstrations and Experiments ... Video clips for the three flame tests shown in Figure 3, and for turning the burner on and off. ...

Henson L. Lee Yu; Perfecto N. Domingo, Jr.; Elliard Roswell S. Yanza; Armando M. Guidote, Jr.

2014-10-13T23:59:59.000Z

187

THE IMPACT OF VARIOUS OXIDIZERS ON THE OVERALL PERFORMACE OF A DIRECT FLAME SOLID OXIDE FUEL CELL.  

E-Print Network [OSTI]

??The power output of a direct-flame solid oxide fuel cell (SOFC) was studied using hydrogen (H2) as the fuel for the flame and various oxidizers,… (more)

Donadio, Nicholas

2010-01-01T23:59:59.000Z

188

Effects of oxygen concentration on radiative loss from normal-gravity and microgravity methane diffusion flames  

SciTech Connect (OSTI)

Laminar diffusion flames of methane, burning in quiescent oxidizing environments at atmospheric pressure, have been studied under both normal-gravity and microgravity conditions. Radiation from these flames is measured using a wide-view-angle, thermopile detector radiometer. The oxidizer was 18, 21, and 30 percent oxygen in nitrogen. 17 refs.

Bahadori, M.Y.; Edelman, R.B.; Stocker, D.P.; Sotos, R.G.; Vaughan, D.F. (Science Applications International Corp., Torrance, CA (United States) Rockwell International Corp., Rocketdyne Div., Canoga Park, CA (United States) NASA, Lewis Research Center, Cleveland, OH (United States))

1992-01-01T23:59:59.000Z

189

A COMPARATIVE STUDY OF THE FORMATION OF AROMATICS IN RICH METHANE FLAMES DOPED BY UNSATURATED COMPOUNDS  

E-Print Network [OSTI]

unsaturated hydrocarbons: allene and propyne, because they are precursors of propargyl radicals which are well as the background gas makes these flames more representative of the combustion of a real fuel compared to a flame by passing through a single pass heat exchanger [14]. Temperature profiles were obtained using a PtRh 3 hal

Boyer, Edmond

190

Large eddy simulation of one diffusion swirling flame European Combustion Meeting 2011  

E-Print Network [OSTI]

.5 7200 75900 Numerical method This research use large eddy simulation (LES) in software ANASYS FLUENT Simulations of Swirling Non-premixed Flames With Flamelet Models: A Comparison of Numerical Methods. FlowLarge eddy simulation of one diffusion swirling flame European Combustion Meeting 2011 Introduction

Berning, Torsten

191

The Effect of the Carrier Gas on Flame lonization Detector Sensitivity  

Science Journals Connector (OSTI)

......fraction of the hydrocarbon converted to CH...ion formation in hydrocarbon flames. The CH...1 ". While no data is presently available...12) that the heats of formation of...chemi-ionization in hydrocarbon flames appears to...International on Combustion, Academic Press......

A.T. Blades

1976-01-01T23:59:59.000Z

192

Combustion and Flame 156 (2009) 771779 Contents lists available at ScienceDirect  

E-Print Network [OSTI]

Combustion and Flame 156 (2009) 771­779 Contents lists available at ScienceDirect Combustion Cylindrical chamber Flow correction Hydrogen Syngas High pressure The effect of nonspherical (i.e. cylindrical are measured for hydrogen and syngas mixtures at atmospheric and elevated pressures. Flow-corrected flame

Ju, Yiguang

193

Comparison of ultraviolet and ultraviolet-infrared flame detection systems  

E-Print Network [OSTI]

detectors view a s1ngle area and a majority of detectors must sense a fire to signal an alarm) and time delay ci r- cu1ts, sensitivity adjustments, and integral self-test lamps and circuitry. Infrared detectors were improved by the addition of vot1ng... have been improved through an evolutionary process to the point where they have become highly reliable, stable and sensitive detectors of flames. With the recent advances in micro- processor based e'lectronics, it has become possible to combine both...

Dayton, Robert Mark

2012-06-07T23:59:59.000Z

194

Scalar dissipation rate based flamelet modelling of turbulent premixed flames  

E-Print Network [OSTI]

curves of ??+ vs N+c conditioned on the progress variable ? for three cases: (a) methane–air, ? = 0.6, Le = 0.96, (b) propane–air, ? = 0.8, Le = 1.83 and (c) methane–air, ? = 1.4, Le = 1.17 . The ? = 0.7 curve for the propane–air case is shown in (d... closure for two mixtures: stoichiometric methane–air with K = 1.0 (•) and lean propane–air with KLe = 1.0 (?). The experimental data of Abdel- Gayed et al. (1987) for K = 1.0 are also shown (?). . . . . . . . . 111 7.9 The comparisons of flame speeds...

Kolla, Hemanth

2010-03-16T23:59:59.000Z

195

Metal rich stars in omega Cen: preliminary FLAMES GTO results  

E-Print Network [OSTI]

I present preliminary results for a sample of ~700 red giants in omega Cen, observed during the Ital-FLAMES Consortium GTO time in May 2003, for the Bologna Project on omega Cen. Preliminary Fe and Ca abundances confirm previous results: while the metal-poor and intermediate populations show a normal halo alpha-enhancement of [alpha/Fe]=$+0.3, the most metal-rich stars show a significantly lower [alpha/Fe]=+0.1. If the metal-rich stars have evolved within the cluster in a process of self-enrichment, the only way to lower their alpha-enhancement would be SNe type Ia intervention.

Pancino, E

2004-01-01T23:59:59.000Z

196

Metal rich stars in omega Cen: preliminary FLAMES GTO results  

E-Print Network [OSTI]

I present preliminary results for a sample of ~700 red giants in omega Cen, observed during the Ital-FLAMES Consortium GTO time in May 2003, for the Bologna Project on omega Cen. Preliminary Fe and Ca abundances confirm previous results: while the metal-poor and intermediate populations show a normal halo alpha-enhancement of [alpha/Fe]=$+0.3, the most metal-rich stars show a significantly lower [alpha/Fe]=+0.1. If the metal-rich stars have evolved within the cluster in a process of self-enrichment, the only way to lower their alpha-enhancement would be SNe type Ia intervention.

E. Pancino

2004-10-28T23:59:59.000Z

197

Polybrominated diphenyl ether flame retardants in the antarctic environment  

E-Print Network [OSTI]

, the historical record of dioxins, PCBs and DDTs in the same cores showed a decreasing trend. At present, PBDEs are recognized as a worldwide pollution problem since they have reached remote areas such as the deep ocean, the Arctic and Antarctica (de Boer et al... that cheerful and warm Brazilian spirit. You are my Aggie family! viii NOMENCLATURE #1; critical value of a statistical test used to reject the null hypothesis ANOVA Analysis of Variance BDE Brominated Diphenyl Ether BFR Brominated Flame Retardant DC...

Yogui, Gilvan Takeshi

2009-05-15T23:59:59.000Z

198

An analytical model for flame propagation in low-Mach-number, variable-density flow  

SciTech Connect (OSTI)

Flame propagation is relevant in many practical applications involving heat transfer and the conversion of heat into mechanical work. Examples of such applications include spark-ignition engines, turbojets, ramjets, afterburners and rockets, although these devices may exhibit nonlocal and nonpropagating combustion phenomena as well. Here, a simple model problem is formulated to describe the coupling between premixed-flame and flow-field dynamics resulting from gas expansion within the flame. The energy conservation equation is integrated analytically across the flame in order to reduce the number of governing equations for the computational problem. A system of six equations and associated boundary conditions are formulated for computation of the time evolution of an initially prescribed three-dimensional velocity field and the flame surface.

Aldredge, R.C. [Univ. of California, Davis, CA (United States). Dept. of Mechanical and Aeronautical Engineering] [Univ. of California, Davis, CA (United States). Dept. of Mechanical and Aeronautical Engineering

1997-12-01T23:59:59.000Z

199

Characterization of a gas burner to simulate a propellant flame and evaluate aluminum particle combustion  

SciTech Connect (OSTI)

This study details the characterization and implementation of a burner designed to simulate solid propellant fires. The burner was designed with the ability to introduce particles (particularly aluminum) into a gas flame. The aluminized flame conditions produced by this burner are characterized based on temperature and heat flux measurements. Using these results, flame conditions are quantified in comparison to other well-characterized reactions including hydrocarbon and propellant fires. The aluminized flame is also used to measure the burning rate of the particles. This work describes the application of this burner for re-creating small-scale propellant flame conditions and as a test platform for experiments that contribute to the development of a particle combustion model, particularly in propellant fires. (author)

Jackson, Matt [Engineering Department, West Texas A and M University, Canyon, TX 79016 (United States); Pantoya, Michelle L. [Mechanical Engineering Department, Texas Tech University, Lubbock, TX 79409 (United States); Gill, Walt [Sandia National Laboratories, Albuquerque, NM 87185 (United States)

2008-04-15T23:59:59.000Z

200

Effects of copper catalytic reactions on the development of supersonic hydrogen flames  

SciTech Connect (OSTI)

Copper species are present in hydrogen flames in arc heated supersonic ramjet testing facilities. Homogeneous and heterogeneous copper catalytic reactions may affect the flame development by enhancing the recombination of hydrogen atoms. Computer simulation is used to investigate the effects of the catalytic reactions on the reaction and ignition times of the flames. The simulation uses a modified general chemical kinetics computer program to simulate the development of copper-contaminated hydrogen flames under scramjet testing conditions. Reaction times of hydrogen flames are found to be reduced due to the copper catalytic effects, but ignition times are much less sensitive to such effects. The reduction of reaction time depends on copper concentration, particle size (if copper is in the condensed phase), and Mach number (or initial temperature and pressure). As copper concentration increases or the particle size decreases, reaction time decreases. As Mach number increases (or pressure and temperature decrease), the copper catalytic effects are greater.

Chang, S.L.; Lottes, S.A.; Berry, G.F.

1992-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

DOE Solar Decathlon: Virtual Tours  

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

News News Photos Daily Photos Gallery of Houses Virtual Tours Videos Product Directory Village Energy Balance Education Sponsors History FAQs Contacts Virtual Tours Explore the U.S. Department of Energy Solar Decathlon 2013 houses through 360° panoramic images. Select a team from the list below to take a peek inside. Then use your mouse and the controls in the bottom right corner of the tour image to rotate your view. U.S. Department of Energy Solar Decathlon Mobile Search Search Search Help More Search Options Orange County Great Park, Irvine, California, Oct. 3-13, 2013 Photo of a large group of cheering decathletes. They stand at the end of the Solar Decathlon 2013 village and hold a banner that says "U.S. Department of Energy Solar Decathlon." U.S. Department of Energy Solar Decathlon

202

Statistical errors in the fractal analysis of flame boundaries  

SciTech Connect (OSTI)

A high speed tomographic technique is used to evaluate the effect of spatial resolution, and requirements for statistical convergence on the fractal analysis of a turbulent, premixed, stoichiometric methane/air flame at high Damkoehler number. The gas velocity at the nozzle exit is 5 m/s, the turbulence intensity is 7%, the integral length scale 3 mm and hence the turbulence Reynolds number is 70. The light source is a copper vapor laser which produces 20ns, 5 mJ pulses at a 4KHz repetition rate. Cylindrical lenses transform the 38mm circular laser beam to a sheet 50 mm high and 0.6 mm thick. A high speed Fastax camera is used to record the tomographic images formed by the scattering of light from oil droplets seeded in the reactant flow. The films are digitized and the flame front extracted from the images by a thresholding technique. Digitization noise, which appears in the fractal plots at approximately twice the pixel resolution, can obscure the inner cutoff. Simple smoothing can remove this problem if the spatial resolution is sufficient. At insufficient resolution smoothing produces plausible resolutes are produced which in fact erroneous. If the inner cutoff is ambiguous the range over which the fractal dimension is determined will be unclear. The wide distribution of fractal dimensions obtained from the individual images indicates the necessity of ensemble averaging the fractal plots if reliable statistical results are to be obtained. 8 refs., 6 figs.

Shepherd, I.G.; Cheng, R.K.

1990-10-01T23:59:59.000Z

203

Flame–vortex interaction in a reacting vortex ring  

Science Journals Connector (OSTI)

Direct numerical simulations are used to study the flame–vortex interaction in a laminar reacting vortex ring. The chemical reaction occurs by a one-step Arrhenius-type reaction that mimics the combustion of typical hydrocarbon and air. The ring is generated by an axisymmetric jet that is impulsed to emit a cold fuel through a nozzle. The fuel enters a quiescent ambient at a much higher temperature. By adjusting the ratio of the ambient and fuel temperatures the ignition either occurs during the formation or post-formation phase of the ring. When ignition occurs during the formation phase of the ring the bulk of combustion is by a flame at the front of the vortex bubble. When ignition is delayed until after the formation phase most of the reaction occurs inside the vortex ring. It is found that premixing the fuel and the oxidizer enhances the amount of product formation. The heat released from the reaction significantly affects production redistribution and diffusion of the vorticity throughout the field. The results of the simulations also reveal that the heat of reaction affects the strain rate fields differently depending on when the ignition of the ring occurs.

J. S. Hewett; C. K. Madnia

1998-01-01T23:59:59.000Z

204

Pocket formation and the flame surface density equation  

SciTech Connect (OSTI)

The occurrence and properties of singularities in the equation for the surface density function {sigma} {triple_bond}{vert_bar}{del}{Phi}{vert_bar} are analyzed analytically and numerically using data from two dimensional direct numerical simulation (DNS) of pocket formation in a premixed methane-air flame. The various stages and the relevant time scales associated with pocket formation were determined in a previous study. It was found that isolated pockets form if and only if a nondegenerate critical point of a saddle point type appears. The appearance of a singularity in the isoline representing the flame front may have implications to modeling of the terms in the surface density function (sdf) approach during such transient events as pocket formation. The sink and source terms in sdf are evaluated in the neighborhood of a critical point using DNS data during pocket formation, and an analytic representation of a scalar in the vicinity of the critical point which allows for the computation of all kinematic properties. The analytic and computational results show that the normal restoration and dissipation terms in the sdf become singular at the critical point when the pocket emerges. Furthermore, the analytic results show that the singularities exactly cancel, and therefore, the main conclusion is that it is unnecessary to model the singular behavior of these terms at critical points. However, closure of their sum is recommended.

Kollman, W. [Univ. of California, Davis, CA (United States); Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility

1998-03-01T23:59:59.000Z

205

A model of particle nucleation in premixed ethylene flames  

SciTech Connect (OSTI)

A detailed model of particle inception is proposed to delve into the physical structure and chemistry of combustion-formed particles. A sectional method is used, from a previously developed kinetic mechanism of particle formation with a double discretization of the particle phase in terms of C and H atom number. The present model also distinguishes between different particle structures based on their state of aggregation; single high molecular mass molecules, cluster of molecules and aggregates of clusters. The model predicts the mass of particles, hydrogen content and internal structure. It represents a first approach in following the chemical evolution and internal structure of the particles formed in flames, coupled with the main pyrolysis and oxidation of the fuel. The model is tested in atmospheric premixed flat flames of ethylene and the effect of fuel equivalence ratio on particle morphology is analyzed. Molecular weight growth of aromatic compounds and the inception of particles are predicted. The morphology of the particles and the number of molecules in the clusters at particle inception are also indicated. (author)

D'Anna, Andrea; Sirignano, Mariano [Dipartimento di Ingegneria Chimica, Universita di Napoli ''Federico II'', Napoli (Italy); Kent, John [School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney (Australia)

2010-11-15T23:59:59.000Z

206

Understanding and predicting soot generation in turbulent non-premixed jet flames.  

SciTech Connect (OSTI)

This report documents the results of a project funded by DoD's Strategic Environmental Research and Development Program (SERDP) on the science behind development of predictive models for soot emission from gas turbine engines. Measurements of soot formation were performed in laminar flat premixed flames and turbulent non-premixed jet flames at 1 atm pressure and in turbulent liquid spray flames under representative conditions for takeoff in a gas turbine engine. The laminar flames and open jet flames used both ethylene and a prevaporized JP-8 surrogate fuel composed of n-dodecane and m-xylene. The pressurized turbulent jet flame measurements used the JP-8 surrogate fuel and compared its combustion and sooting characteristics to a world-average JP-8 fuel sample. The pressurized jet flame measurements demonstrated that the surrogate was representative of JP-8, with a somewhat higher tendency to soot formation. The premixed flame measurements revealed that flame temperature has a strong impact on the rate of soot nucleation and particle coagulation, but little sensitivity in the overall trends was found with different fuels. An extensive array of non-intrusive optical and laser-based measurements was performed in turbulent non-premixed jet flames established on specially designed piloted burners. Soot concentration data was collected throughout the flames, together with instantaneous images showing the relationship between soot and the OH radical and soot and PAH. A detailed chemical kinetic mechanism for ethylene combustion, including fuel-rich chemistry and benzene formation steps, was compiled, validated, and reduced. The reduced ethylene mechanism was incorporated into a high-fidelity LES code, together with a moment-based soot model and models for thermal radiation, to evaluate the ability of the chemistry and soot models to predict soot formation in the jet diffusion flame. The LES results highlight the importance of including an optically-thick radiation model to accurately predict gas temperatures and thus soot formation rates. When including such a radiation model, the LES model predicts mean soot concentrations within 30% in the ethylene jet flame.

Wang, Hai (University of Southern California, Los Angeles, CA); Kook, Sanghoon; Doom, Jeffrey; Oefelein, Joseph Charles; Zhang, Jiayao; Shaddix, Christopher R.; Schefer, Robert W.; Pickett, Lyle M.

2010-10-01T23:59:59.000Z

207

Worldwide R&D of Virtual Observatory  

E-Print Network [OSTI]

Virtual Observatory (VO) is a data intensive online astronomical research and education environment, taking advantages of advanced information technologies to achieve seamless and uniform access to astronomical information. The concept of VO was introduced in late of 1990s to meet challenges brought up with data avalanche in astronomy. This paper reviews current status of International Virtual Observatory Alliance, technical highlights from world wide VO projects, and a brief introduction of Chinese Virtual Observatory.

Chenzhou Cui; Yongheng Zhao

2007-11-27T23:59:59.000Z

208

Finite-rate chemistry and transient effects in direct numerical simulations of turbulent nonpremixed flames  

SciTech Connect (OSTI)

Three-dimensional direct numerical simulations (DNS) of turbulent nonpremixed flames including finite-rate chemistry and heat release effects were performed. Two chemical reaction models were considered: (1) a single-step global reaction model in which the heat release and activation energy parameters are typical combustion applications, and (2) a two-step reaction model to stimulate radical production and consumption and to compare against the single-step model. The model problem consists of the interaction between an initially unstained laminar diffusion flame and a three-dimensional field of homogeneous turbulence. Conditions ranging from fast chemistry to the pure mixing limit were studied by varying a global Damkoehler number. Results suggest that turbulence-induced mixing acting along the stoichiometric line leads to a strong modification of the inner structure of the turbulent flame compared with a laminar strained flame, resulting in intermediate species concentrations well above the laminar prediction. This result is consistent the experimental observations. Comparison of the response of the turbulent flame structure due to changes in the scalar dissipation rate with a steady strained laminar flame reveals that unsteady strain rates experienced by the turbulent flame may be responsible for h3e observed high concentrations of reaction intermediates.

Mahalingam, S. [Univ. of Colorado, Boulder, CO (United States). Center for Combustion Research] [Univ. of Colorado, Boulder, CO (United States). Center for Combustion Research; Chen, J.H. [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility] [Sandia National Labs., Livermore, CA (United States). Combustion Research Facility; Vervisch, L. [CORIA, Rouen (France). Laboratoire de Mechanique des Fluides Numeriques] [CORIA, Rouen (France). Laboratoire de Mechanique des Fluides Numeriques

1995-08-01T23:59:59.000Z

209

Caterpillar, Argonne undertake cooperative virtual engine design...  

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

Caterpillar, Argonne undertake cooperative virtual engine design, control project By Jared Sagoff * June 30, 2014 Tweet EmailPrint ARGONNE, Ill - Internal combustion engines are...

210

CFD Tools in Stirling Engine Virtual Design  

Science Journals Connector (OSTI)

A successful realization of Stirling engines is conditioned by its correct conceptual design ... supply engine are used for virtual prototype of Stirling engine.

V. Pistek; P. Novotny

2007-01-01T23:59:59.000Z

211

Stirling Engine Development Using Virtual Prototyping  

Science Journals Connector (OSTI)

A successful realization of Stirling engines is conditioned by its correct conceptual design ... are used for virtual prototype of 3 kW Stirling engine with Rhombic mechanism.

V. Píšt?k; P. Novotný

2012-01-01T23:59:59.000Z

212

Virtual Training Centre For CNC: a Sample Virtual Training Environment Mehmet Sahin1  

E-Print Network [OSTI]

Virtual Training Centre For CNC: a Sample Virtual Training Environment Mehmet Sahin1 , Süleyman bilalis@dpem.tuc.gr Abstract It is a fact that virtual training has been a scope of interest for vocational training for a very long time. However, it needs more time to be more common in all specific

Aristomenis, Antoniadis

213

Stabilizer Formalism for Operator Quantum Error Correction  

Science Journals Connector (OSTI)

Operator quantum error correction is a recently developed theory that provides a generalized and unified framework for active error correction and passive error avoiding schemes. In this Letter, we describe these codes using the stabilizer formalism. This is achieved by adding a gauge group to stabilizer codes that defines an equivalence class between encoded states. Gauge transformations leave the encoded information unchanged; their effect is absorbed by virtual gauge qubits that do not carry useful information. We illustrate the construction by identifying a gauge symmetry in Shor’s 9-qubit code that allows us to remove 3 of its 8 stabilizer generators, leading to a simpler decoding procedure and a wider class of logical operations without affecting its essential properties. This opens the path to possible improvements of the error threshold of fault-tolerant quantum computing.

David Poulin

2005-12-01T23:59:59.000Z

214

Simulations of flame acceleration and deflagration-to-detonation transitions in methane-air systems  

SciTech Connect (OSTI)

Flame acceleration and deflagration-to-detonation transitions (DDT) in large obstructed channels filled with a stoichiometric methane-air mixture are simulated using a single-step reaction mechanism. The reaction parameters are calibrated using known velocities and length scales of laminar flames and detonations. Calculations of the flame dynamics and DDT in channels with obstacles are compared to previously reported experimental data. The results obtained using the simple reaction model qualitatively, and in many cases, quantitatively match the experiments and are found to be largely insensitive to small variations in model parameters. (author)

Kessler, D.A.; Gamezo, V.N.; Oran, E.S. [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, Washington, DC (United States)

2010-11-15T23:59:59.000Z

215

CONTROL OF POLLUTANT EMISSIONS IN NATURAL GAS DIFFUSION FLAMES BY USING CASCADE BURNERS  

SciTech Connect (OSTI)

The goal of this exploratory research project is to control the pollutant emissions of diffusion flames by modifying the air infusion rate into the flame. The modification was achieved by installing a cascade of venturis around the burning gas jet. The basic idea behind this technique is controlling the stoichiometry of the flame through changing the flow dynamics and rates of mixing in the combustion zone with a set of venturis surrounding the flame. A natural gas jet diffusion flame at burner-exit Reynolds number of 5100 was examined with a set of venturis of specific sizes and spacing arrangement. The thermal and composition fields of the baseline and venturi-cascaded flames were numerically simulated using CFD-ACE+, an advanced computational environment software package. The instantaneous chemistry model was used as the reaction model. The concentration of NO was determined through CFD-POST, a post processing utility program for CFD-ACE+. The numerical results showed that, in the near-burner, midflame and far-burner regions, the venturi-cascaded flame had lower temperature by an average of 13%, 19% and 17%, respectively, and lower CO{sub 2} concentration by 35%, 37% and 32%, respectively, than the baseline flame. An opposite trend was noticed for O{sub 2} concentration; the cascaded flame has higher O{sub 2} concentration by 7%, 26% and 44%, in average values, in the near-burner, mid-flame and far-burner regions, respectively, than in the baseline case. The results also showed that, in the near-burner, mid-flame, and far-burner regions, the venturi-cascaded flame has lower NO concentrations by 89%, 70% and 70%, in average values, respectively, compared to the baseline case. The numerical results substantiate that venturi-cascading is a feasible method for controlling the pollutant emissions of a burning gas jet. In addition, the numerical results were useful to understand the thermo-chemical processes involved. The results showed that the prompt-NO mechanism plays an important role besides the conventional thermal-NO mechanism. The computational results of the present study need to be validated experimentally.

Dr. Ala Qubbaj

2001-12-30T23:59:59.000Z

216

An Inverted Co-Flow Diffusion Flame for Producing Soot  

SciTech Connect (OSTI)

We developed an inverted, co-flow, methane/air/nitrogen burner that generates a wide range of soot particles sizes and concentrations. By adjusting the flow rates of air, methane, and nitrogen in the fuel, the mean electric mobility diameter and number concentration are varied. Additional dilution downstream of the flame allows us to generate particle concentrations spanning those produced by spark-ignited and diesel engines: particles with mean diameters between 50 and 250 nm and number concentrations from 4.7 {center_dot} 10{sup 4} to 10{sup 7} cm{sup -3}. The range of achievable number concentrations, and therefore volume concentrations, can be increased by a factor of 30 by reducing the dilution ratio. These operating conditions make this burner valuable for developing and calibrating diagnostics as well as for other studies involving soot particles.

Stipe, Christopher B.; Higgins, Brian S.; Lucas, Donald; Koshland, Catherine P.; Sawyer, Robert F.

2005-06-21T23:59:59.000Z

217

Reaction zone visualisation in swirling spray n-heptane flames  

E-Print Network [OSTI]

process and consumed in the subsequent high temperature oxidation. Formaldehyde LIF was used for autoignition of methane jets [6], methanol, ethanol and acetone spray jet flames [7,8], and diesel fuel [9-11] and n-heptane [11,12] in HCCI engines. Najm... intensifier was 30,000 FL/FC and 80,000 FL/FC for CH2O and OH respectively. The laser powers were 12 mJ/pulse for OH PLIF and 300 mJ/pulse for CH2O PLIF. The intensifiers were triggered off the Q switch of each laser 6 with a gate of 220 ns. The CH2O PLIF...

Yuan, R.; Kariuki, J.; Dowlut, A.; Balachandran, R.; Mastorakos, E.

2014-06-26T23:59:59.000Z

218

Mechanisms governing fine particulate emissions from coal flames  

SciTech Connect (OSTI)

The primary objective of this program was to provide a basic understanding of the principal processes that govern the formation of particulate matter in the 0.5--10 {mu}m size range in pulverized coal flames. The mechanism that produces ash particles in this size range is not clear. Particle sizes smaller than the 0.5--10 {mu}m size range are generally accepted to result from a vaporization/condensation mechanism while particles larger than this size result from the coalescence of ash in coal particles which may breakup as they burn. This program combined experimental and theoretical studies to understand the mechanisms which control the production of ash in the 0.5--10 {mu}m size range. (VC)

Newton, G.H.; Schieber, C.; Socha, R.G.; Kramlich, J.C.

1990-04-01T23:59:59.000Z

219

Mechanisms governing fine particulate emissions from coal flames. Final report  

SciTech Connect (OSTI)

The primary objective of this program was to provide a basic understanding of the principal processes that govern the formation of particulate matter in the 0.5--10 {mu}m size range in pulverized coal flames. The mechanism that produces ash particles in this size range is not clear. Particle sizes smaller than the 0.5--10 {mu}m size range are generally accepted to result from a vaporization/condensation mechanism while particles larger than this size result from the coalescence of ash in coal particles which may breakup as they burn. This program combined experimental and theoretical studies to understand the mechanisms which control the production of ash in the 0.5--10 {mu}m size range. (VC)

Newton, G.H.; Schieber, C.; Socha, R.G.; Kramlich, J.C.

1990-04-01T23:59:59.000Z

220

NO{sub x} control by flame management  

SciTech Connect (OSTI)

In the control of emissions from power generation boilers combustion modification, in the form of low NO{sub x} burner (LNB) design, is recognized as the basic and economic technique for minimising NO{sub x} production. Depending upon the application LNB`s alone may offer sufficient NO{sub x} control or may be used in conjunction with changes in boiler operating techniques to achieve ultra-low NO{sub x} operation. LNB designs are based on well established principles of fuel and air staging which control the mixing of fuel and combustion air in order to establish the flame chemistry and temperature conditions conducive to minimising NO{sub x} formation. These mixing processes need to be considered in conjunction with the fuel characteristics for maximum effectiveness.

Allen, J.W.; Beal, P.R. [International Combustion Ltd., Derby (United Kingdom)

1995-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Collaborative Virtual Training with Physical and Communicative Autonomous Agents.  

E-Print Network [OSTI]

Collaborative Virtual Training with Physical and Communicative Autonomous Agents. Thomas Lopez1, Conversational Agents, Autonomous Actors, Avatars, Virtual Reality Introduction The use of virtual reality Environments for Train- ing (CVETs) where real users and autonomous agents efficiently collaborate toward

222

Multimodal astronaut virtual training prototype  

Science Journals Connector (OSTI)

A few dedicated training simulator applications exist that mix realistic interaction devices—like real cockpits in flight simulators—with virtual environment (VE) components. Dedicated virtual reality (VR) systems have been utilized also in astronaut training. However there are no detailed descriptions of projection wall VR systems and related interaction techniques for astronaut assembly training in zero gravity conditions. Back projection technology tends to have certain advantages over head mounted displays including less simulation sickness and less restricted user movement. A prototype was built to evaluate the usefulness of projection technology \\{VEs\\} and interaction techniques for astronaut training. This was achieved by first constructing a PC cluster-based general purpose VE software and hardware platform. This platform was used to implement a testing prototype for astronaut assembly sequence training. An interaction tool battery was designed for the purposes of viewpoint control and object handling. A selected training task was implemented as a case study for further analysis based on laptop usage in the Fluid Science Laboratory (FSL) inside the Columbus module in the International Space Station (ISS). User tests were conducted on the usability of the prototype for the intended training purpose. The results seem to indicate that projection technology-based VE systems and suitably selected interaction techniques can be successfully utilized in zero gravity training operations.

Jukka Rönkkö; Jussi Markkanen; Raimo Launonen; Marinella Ferrino; Enrico Gaia; Valter Basso; Harshada Patel; Mirabelle D’Cruz; Seppo Laukkanen

2006-01-01T23:59:59.000Z

223

Rapid Prototyping of Virtual Environments  

Science Journals Connector (OSTI)

The goal of virtual reality is to fully or partially immerse a human in a visually coupled environment. By tracking the position and orientation of the user with sensors designed for this purpose and by coupling these measurements with a high?performance computer graphics system we can generate a computer?synthesized view of a virtual environment that responds to the user’s movements. Thus the user does not just see a visual display on a terminal but is immersed within the display. VR also allows natural real?time interaction with the VE. Instead of a GUI the system uses perceptual and multi?modal interfaces (such as gesture audio and speech recognition) to interact with the data. Natural locomotion devices let the user navigate through the VE. Also because of the size of the typical projection?based VR display (CAVEs and workbenches) groups of scientists and engineers can more easily work together to interpret data making full use of the 3D portrayal.

Marco Lanzagorta; Robert Rosenberg; Lawrence J. Rosenblum; Eddy Y. Kuo

2000-01-01T23:59:59.000Z

224

Virtual Machine Monitors 36.1 Introduction  

E-Print Network [OSTI]

36 Virtual Machine Monitors 36.1 Introduction Years ago, IBM sold mainframes to large organizations, and a problem arose: what if the organization wanted to run different operating systems on the machine? (some yet another level of indirection in the form of a virtual machine monitor, or VMM or just monitor

Sheridan, Jennifer

225

Green Virtual Enterprises and their Breeding Environments  

E-Print Network [OSTI]

Green Virtual Enterprises and their Breeding Environments David Romero, Arturo Molina Tecnológico. This paper introduces a Green Virtual Enterprise (GVE) model as an emerging sustainable manufacturing and logistics mode focused on offering, delivering and recovering green products to/from the market, under

Paris-Sud XI, Université de

226

Virtual Sensors: Abstracting Data from Physical Sensors  

E-Print Network [OSTI]

Virtual Sensors: Abstracting Data from Physical Sensors TR-UTEDGE-2006-001 Sanem Kabadayi Adam Pridgen Christine Julien © Copyright 2006 The University of Texas at Austin #12;Virtual Sensors: Abstracting Data from Physical Sensors Sanem Kabadayi, Adam Pridgen, and Christine Julien The Center

Julien, Christine

227

Virtualizing Operating Systems for Seamless Distributed Environments  

E-Print Network [OSTI]

Virtualizing Operating Systems for Seamless Distributed Environments 1 Tom Boyd and Partha Dasgupta. Abstract Applications and operating systems can be augmented with extra functionality by injecting bindings. This is called virtualiza- tion. We are developing a virtualizing Operating System (vOS) residing

Dasgupta, Partha

228

On The Toxicity of Flame Retardants in Buildings and What Can Be Done About  

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

On The Toxicity of Flame Retardants in Buildings and What Can Be Done About On The Toxicity of Flame Retardants in Buildings and What Can Be Done About It Speaker(s): Arlene Blum Date: November 3, 2010 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: William Fisk Polystyrene, polyisocyanurate, and polyurethane are insulation materials that increase energy efficiency and whose use in buildings, especially energy efficient buildings, is growing rapidly. At the same time, the flame retardants currently in use with these materials are often chemicals that are known to be toxic or have not been adequately evaluated for their impact on human health and the environment. For example, all polystyrene foam insulation used in buildings is treated with HBCD, a persistent, bioaccumulative, and toxic flame retardant. The impacts of exposure to

229

Coal Particle Measurement in a Pulverized Coal Flame with Digital Inline Holography  

Science Journals Connector (OSTI)

Digital inline holography with pulse illumination was applied to measure the 3D position and size of the burning coal particles in a laboratory-scale pulverized coal flame under strong...

Wu, Yingchun; Wu, Xuecheng; Zhou, Binwu; Yang, Jing; Chen, Linghong; Peng, Yueyu; Qiu, Kunzan; Grehan, Gerard; Cen, Kefa

230

Investigation of the Syngas Flame Characteristics at Elevated Pressures Using Optical and Laser Diagnostic Methods  

Science Journals Connector (OSTI)

The effect of pressure on the characteristics of syngas flames is investigated under gas turbine relevant...*...chemiluminescence imaging. An optically accessible combustor fitted with a swirl burner was operated...

Rajesh Sadanandan; Peter Kutne; Adam Steinberg…

2012-09-01T23:59:59.000Z

231

Synthesis of Highly Efficient Flame Retardant High-Density Polyethylene Nanocomposites with Inorgano-Layered Double  

E-Print Network [OSTI]

Synthesis of Highly Efficient Flame Retardant High-Density Polyethylene Nanocomposites, Harbin 150080, P. R. China ABSTRACT: High-density polyethylene (HDPE) polymer nanocomposites containing. INTRODUCTION High density polyethylene (HDPE) has good electrical proper- ties, high stiffness, and tensile

Guo, John Zhanhu

232

Method for determining effective flame emissivity in a rotary kiln incinerator burning solid waste  

Science Journals Connector (OSTI)

Temperature is the most important parameter for the improvement of combustion efficiency and the control of pollutants. In order to obtain accurate flame temperatures in a rotary kiln incinerator using non-int...

Jin-cai Du; Qun-xing Huang; Jian-hua Yan

2012-12-01T23:59:59.000Z

233

Effect of Plasma Pretreatment Followed by Nanoclay Loading on Flame Retardant Properties of Cotton Fabric  

Science Journals Connector (OSTI)

In this research work the effect of plasma treatment with nitrogen gas followed by nanoclay treatment on flame retardancy of cotton fabrics ... , nitrogen plasma pretreatment has synergistic effect on nanoclay fo...

Sheila Shahidi; Mahmood Ghoranneviss

2014-02-01T23:59:59.000Z

234

Multifractal detrended fluctuation analysis of combustion flames in four-burner impinging entrained-flow gasifier  

E-Print Network [OSTI]

On a laboratory-scale testing platform of impinging entrained-flow gasifier with four opposed burners, the flame images for diesel combustion and gasification process were measured with a single charge coupled device (CCD) camera. The two-dimensional multifractal detrended fluctuation analysis was employed to investigate the multifractal nature of the flame images. Sound power-law scaling in the annealed average of detrended fluctuations was unveiled when the order $q>0$ and the multifractal feature of flame images were confirmed. Further analyses identified two multifractal parameters, the minimum and maximum singularity $\\alpha_{\\min}$ and $\\alpha_{\\max}$, serving as characteristic parameters of the multifractal flames. These two characteristic multifractal parameters vary with respect to different experimental conditions.

Niu, Miao-Ren; Yan, Zhuo-Yong; Guo, Qing-Hua; Liang, Qin-Feng; Wang, Fu-Chen; Yu, Zun-Hong

2007-01-01T23:59:59.000Z

235

Large eddy simulations of premixed turbulent flame dynamics : combustion modeling, validation and analysis  

E-Print Network [OSTI]

High efficiency, low emissions and stable operation over a wide range of conditions are some of the key requirements of modem-day combustors. To achieve these objectives, lean premixed flames are generally preferred as ...

Kewlani, Gaurav

2014-01-01T23:59:59.000Z

236

The Plasma Flame: Development and Application of a Hybrid Plasma at Atmospheric Pressure.  

E-Print Network [OSTI]

??The focus of this work was to develop a hybrid plasma at atmospheric pressure, which we have deemed the “plasma flame†. This discharge is… (more)

King, Matthew Russell

2009-01-01T23:59:59.000Z

237

Laser induced spark ignition of coaxial methane/oxygen/nitrogen diffusion flames  

Science Journals Connector (OSTI)

We report the laser induced spark ignition (LSI) of coaxial methane/oxygen/nitrogen diffusion flames using the 1064 nm output of a Q-switched Nd:YAG laser. The minimum ignition energy...

Li, Xiaohui; Yu, Yang; Yu, Xin; Liu, Chang; Fan, Rongwei; Chen, Deying

2014-01-01T23:59:59.000Z

238

THE COMBUSTION OF SOLVENT REPINED COAL IN AN OPPOSED FLOW DIFFUSION FLAME  

E-Print Network [OSTI]

R.F. (1977). Combustion of coal in an opposed flow diffusionpulverized, solvent-refined coal. ASME Paper No. 76-WA/FU-6.OF SOLVENT REFINED COAL IN AN OPPOSED FLOW DIFFUSION FLAME*

Chin, W.K.

2011-01-01T23:59:59.000Z

239

Non-adiabatic flamelet modeling for combustion processes of oxy-natural gas flame  

Science Journals Connector (OSTI)

In order to realistically predict the combustion characteristics of the oxy-fuel flame, the present study employs the non-adiabatic flamelet approach. In this combustion model, the detailed equilibrium chemist...

Gunhong Kim; Yongmo Kim

2005-09-01T23:59:59.000Z

240

T-678: Red Hat Enterprise Virtualization Hypervisor VLAN Packet...  

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

Virtualization Hypervisor VLAN Packet Processing Flaw Lets Remote Users Deny Service T-678: Red Hat Enterprise Virtualization Hypervisor VLAN Packet Processing Flaw Lets...

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Integrated Virtual Lab in Supporting Heavy Duty Engine and Vehicle...  

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

Virtual Lab in Supporting Heavy Duty Engine and Vehicle Emission Rulemaking Integrated Virtual Lab in Supporting Heavy Duty Engine and Vehicle Emission Rulemaking Presentation...

242

Virtual Center of Excellence for Hydrogen Storage - Chemical...  

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

Virtual Center of Excellence for Hydrogen Storage - Chemical Hydrides Virtual Center of Excellence for Hydrogen Storage - Chemical Hydrides Presentation from the Hydrogen Storage...

243

Combustor oscillating pressure stabilization and method  

DOE Patents [OSTI]

High dynamic pressure oscillations in hydrocarbon-fueled combustors typically occur when the transport time of the fuel to the flame front is at some fraction of the acoustic period. These oscillations are reduced to acceptably lower levels by restructuring or repositioning the flame front in the combustor to increase the transport time. A pilot flame front located upstream of the oscillating flame and pulsed at a selected frequency and duration effectively restructures and repositions the oscillating flame in the combustor to alter the oscillation-causing transport time.

Gemmen, Randall S. (Morgantown, WV); Richards, George A. (Morgantown, WV); Yip, Mui-Tong Joseph (Morgantown, WV); Robey, Edward H. (Westover, WV); Cully, Scott R. (Morgantown, WV); Addis, Richard E. (Smithfield, PA)

1998-01-01T23:59:59.000Z

244

EIS-0351: Operation of Flaming Gorge Dam, Colorado River Storage Project, Colorado River, UT  

Broader source: Energy.gov [DOE]

The Secretary of the United States Department of the Interior (Secretary), acting through the Bureau of Reclamation (Reclamation), is considering whether to implement a proposed action under which Flaming Gorge Dam would be operated to achieve the flow and temperature regimes recommended in the September 2000 report Flow and Temperature Recommendations for Endangered Fishes in the Green River Downstream of Flaming Gorge Dam (2000 Flow and Temperature Recommendations), published by the Upper Colorado River Endangered Fish Recovery Program (Recovery Program).

245

Optical determination of incipient soot particle concentrations in ethene laminar diffusion flames.  

SciTech Connect (OSTI)

Recent studies in premixed flames have shown the existence of ''transparent particles.'' These particles, 2 nm in size and in high number densities are considered to be a phase transitional between the gas phase PAH species and particulate soot. In the present study, various optical diagnostics were evaluated for measuring the concentration of these particles in situ, Through such evaluations, a technique using extinction at two wavelengths was found to be ideal. While employing such a technique, the volume fractions of these particles in an ethene laminar diffusion flame were measured. Low in the flame, these particles were found to be concentrated in the fuel rich core, while at higher locations, they could be found with appreciable volume fractions even in the soot laden regions. Having given due consideration for the errors due to uncertainties in the optical constants, we report the existence of these particles in an ethene flame with volume fractions comparable to those of soot. Also, similar measurements performed in a low sooting ethene/methanol flame show the concentration of these particles to be of the same order of magnitude as in a pure ethene flame.

Gupta, S. B.; Santoro, R. J.

1999-07-06T23:59:59.000Z

246

Synthesis and thermal studies of flexible polyurethane nanocomposite foams obtained using nanoclay modified with flame retardant compound  

Science Journals Connector (OSTI)

This work presents thermal studies of nanocomposites based on the flexible polyurethane (PU) matrix and filled using montmorillonite organically modified with organophosphorus flame retardant compound. Flexibl...

?ukasz Piszczyk; Magdalena Danowska…

2014-11-01T23:59:59.000Z

247

Development of virtual-labs based on complex Modelica models using VirtualLabBuilder  

Science Journals Connector (OSTI)

The feasibility of implementing virtual-labs based on complex Modelica models is demonstrated. To this end, the design and implementation of the following three virtual-labs is discussed: 1) a virtual-lab of a double-pipe heat exchanger, which is a useful tool for control education; 2) a virtual-lab describing the thermodynamic behaviour of the solar house, which is based on a complex Modelica model developed by other authors; 3) the virtual-lab of a drum-type washing machine, which is an industrial application useful as design aid. The graphical user interface has been implemented by using the VirtualLabBuilder library, which can be freely downloaded from http:/ /www.euclides.dia.uned.es.

Carla Martin-Villalba; Felix Martinez; Alfonso Urquia; Sebastian Dormido

2010-01-01T23:59:59.000Z

248

The design space of dynamic interactive virtual environments  

Science Journals Connector (OSTI)

Virtual environments have become a key component of many fields and the critical component of virtual reality applications. Due to their virtual nature, they can accommodate an infinite number of possibilities. A theoretical work is presented, which ... Keywords: 3D user interaction, Dynamic interactive VEs, VR systems, Virtual environments

Kristopher J. Blom; Steffi Beckhaus

2014-06-01T23:59:59.000Z

249

Effects of syngas composition on combustion induced vortex breakdown (CIVB) flashback in a swirl stabilized combustor  

Science Journals Connector (OSTI)

Flame flashback attributed to combustion induced vortex breakdown (CIVB) is a major design challenge for swirl stabilized burner combustors. This paper presents an experimental investigation of combustion induced vortex breakdown (CIVB) flashback propensity for flames yielded from Hydrogen (H2)–Carbon Monoxide (CO) fuel blends and actual synthesized gas (syngas) mixtures. A two-fold experimental approach, consisting of a high definition digital imaging system and a high speed PIV system, was employed. The main emphasis was on the effect of concentration of different constituents in fuel mixtures on flashback limit. In addition, the effect of Swirl Number on flashback propensity was discussed. The percentage of H2 in fuel mixtures played the dominant role when CIVB flashback occurred. For a given air mass flow rate, the mixture containing a higher percentage of H2 underwent flashback at much leaner conditions. Flashback maps for actual syngas fuel compositions showed a distinct behavior when various concentrations of diluents were introduced in the mixture. For the two major diluents tested, carbon dioxide (CO2) and nitrogen dioxide (NO2), CO2 was more dominant. The effect of Swirl Number on the flashback propensity was also tested and showed a decrease with an increase in Swirl Number. The final portion of this paper also provides an analysis of flow field of reacting flames which revealed complex vortex–chemistry interactions leading to vortex breakdown and flashback. Based on the experimental results a parametric model similar to Peclet Number approach was developed employing a flame quenching concept. A value of the quench parameter, Cquench was obtained from the correlation of flow Peclet Number and flame Peclet Number, which was observed to be dominated by the fuel composition rather than Swirl Number.

Bidhan Dam; Gilberto Corona; Mir Hayder; Ahsan Choudhuri

2011-01-01T23:59:59.000Z

250

Development of a New Flame Speed Vessel to Measure the Effect of Steam Dilution on Laminar Flame Speeds of Syngas Fuel Blends at Elevated Pressures and Temperatures  

E-Print Network [OSTI]

, including the H2O. .............................................................................................................................................. 35 Table 6 Standard L9 DOE test matrix for four factors (A-D) at three levels (1-3) (Ross... sensitivity analysis based on the maximum difference between the averaged laminar flame speeds at each DOE level (1, 2, or 3) for four oxygen equivalence ratios. ...................................................................................... 41 Table...

Krejci, Michael

2012-07-16T23:59:59.000Z

251

Flame structure of wall-impinging diesel fuel sprays injected by group-hole nozzles  

SciTech Connect (OSTI)

This paper describes an investigation of the flame structure of wall-impinging diesel sprays injected by group-hole nozzles in a constant-volume combustion vessel at experimental conditions typical of a diesel engine. The particular emphasis was on the effect of the included angle between two orifices (0-15 deg. in current study) on the flame structure and combustion characteristics under various simulated engine load conditions. The laser absorption scattering (LAS) technique was applied to analyze the spray and mixture properties. Direct flame imaging and OH chemiluminescence imaging were utilized to quantify the ignition delay, flame geometrical parameters, and OH chemiluminescence intensity. The images show that the asymmetric flame structure emerges in wall-impinging group-hole nozzle sprays as larger included angle and higher engine load conditions are applied, which is consistent with the spray shape observed by LAS. Compared to the base nozzle, group-hole nozzles with large included angles yield higher overall OH chemiluminescence intensity, wider flame area, and greater proportion of high OH intensity, implying the better fuel/air mixing and improved combustion characteristics. The advantages of group-hole nozzle are more pronounced under high load conditions. Based on the results, the feasibility of group-hole nozzle for practical direct injection diesel engines is also discussed. It is concluded that the asymmetric flame structure of a group-hole nozzle spray is favorable to reduce soot formation over wide engine loads. However, the hole configuration of the group-hole nozzle should be carefully considered so as to achieve proper air utilization in the combustion chamber. Stoichiometric diesel combustion is another promising application of group-hole nozzle. (author)

Gao, Jian; Moon, Seoksu; Nishida, Keiya; Matsumoto, Yuhei [Department of Mechanical System Engineering, University of Hiroshima, Higashi-Hiroshima, 739-8527 (Japan); Zhang, Yuyin [Department of Mechanical Engineering, Tokyo Denki University, Tokyo, 101-8457 (Japan)

2009-06-15T23:59:59.000Z

252

Mobility of Negative Ions in Flames by the Hall Effect Method  

Science Journals Connector (OSTI)

Variation with potential gradient of mobility of negative flame ions.—Using a flat salted flame, previously described by Wilson, between the poles of an electromagnet giving a field of 5000 gauss, the horizontal potential gradient X due to the current sent between two Pt electrodes and also the vertical potential gradient Y due to the Hall effect, were measured by means of two Pt sounding wires which could be rotated about a horizontal axis and which were connected to a quadrant electrometer. For a flame containing potassium carbonate the mobility k2=YHX was found to decrease from 26 m/sec for 1 volt/cm when the potential gradient was 1 volt/cm, to 16 m/sec for a gradient of 30 volts/cm. For a flame free from salt the mobility was some-what greater, decreasing from 26.5 m/sec for 5 volts/cm to 16 m/sec for 50 volts/cm. However, wide variation of concentration produced so little effect on the mobility that it could not be detected with certainty. The magneto-resistance effect which Heaps1 has shown enters into the mobility equation, was so small as to be negligible.Asymmetry of the Hall effect in flames.—The Hall effect was found to vary slightly with the direction of the magnetic field, the asymmetry being greater the greater the amount of salt in the flame. This asymmetry was probably due to the effect of the magnetic field on the upward velocity of the flame gases, which was evident in these experiments.

J. S. Watt

1925-01-01T23:59:59.000Z

253

DOE Virtual University | Department of Energy  

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

Services » Learning & Development » DOE Virtual University Services » Learning & Development » DOE Virtual University DOE Virtual University Learn more about DVU The Department of Energy Virtual University (DVU) is a central venue for executing, managing, partnering, and sharing corporate learning activities and programs. Read more Training Resources The Training Resources webpage has the links to the commonly used course catalogs and course schedules used by DOE employees. Course registration links can also be found here. Read more College of Science The College of Science's (CS) mission is to provide DOE employees with the information resources necessary to keep current in the field of science. Read more College of Health Safety & Security Through the National Training Center (NTC), the Office of Health, Safety

254

National Energy Literacy Virtual Town Hall  

Broader source: Energy.gov [DOE]

The webinar will be a dynamic, virtual conversation for educators about ongoing efforts from across the country in utilizing the Department of Energy's Energy Literacy Framework to address one of our nation's’ biggest national challenges, energy illiteracy.

255

BioenergizeME Virtual Science Fair: Bioenergy  

Broader source: Energy.gov [DOE]

This infographic was created by students from Sun Valley High School in Aston, PA, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

256

Webcast: National Energy Literacy Virtual Town Hall  

Broader source: Energy.gov [DOE]

On August 5, 2014, the Department of Energy (DOE) hosted a dynamic virtual conversation of ongoing efforts from across the country in utilizing the Energy Literacy Framework to address one of our...

257

Virtual tour: INL's space battery facility  

SciTech Connect (OSTI)

This virtual tour shows how INL fuels and tests nuclear power systems for deep space missions. To learn more about INL's contribution to the Mars Science Laboratory, visit http://www.inl.gov/marsrover.

Johnson, Steve

2011-01-01T23:59:59.000Z

258

Virtual Design of Stirling Engine Combustion Chamber  

Science Journals Connector (OSTI)

The paper deals with the designing of a combustion chamber of the Stirling engine using the CFD approach. Virtual prototypes enabled ... . The presented results help to increase the Stirling engine efficiency tog...

Z. Kaplan; P. Novotný; V. Píšt?k

2010-01-01T23:59:59.000Z

259

Virtual tour: INL's space battery facility  

ScienceCinema (OSTI)

This virtual tour shows how INL fuels and tests nuclear power systems for deep space missions. To learn more about INL's contribution to the Mars Science Laboratory, visit http://www.inl.gov/marsrover.

Johnson, Steve

2013-05-28T23:59:59.000Z

260

Residential heating oil prices virtually unchanged  

U.S. Energy Information Administration (EIA) Indexed Site

heating oil prices virtually unchanged The average retail price for home heating oil fell 4-tenths of a penny from a week ago to 3.95 per gallon. That's down 8-tenths of a penny...

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Residential heating oil prices virtually unchanged  

U.S. Energy Information Administration (EIA) Indexed Site

4 Residential heating oil prices virtually unchanged The average retail price for home heating oil rose 2-tenths of a cent from a week ago to 4.24 per gallon. That's up 8.2 cents...

262

Use of virtual machines in information systems  

E-Print Network [OSTI]

This paper presents a scheme using the virtual machine concept for creating: 1) An environment for increasing the effectiveness of researchers who must use analytical, modeling systems and have complex data management ...

Donovan, John J.

1975-01-01T23:59:59.000Z

263

Robotics virtual rail system and method  

DOE Patents [OSTI]

A virtual track or rail system and method is described for execution by a robot. A user, through a user interface, generates a desired path comprised of at least one segment representative of the virtual track for the robot. Start and end points are assigned to the desired path and velocities are also associated with each of the at least one segment of the desired path. A waypoint file is generated including positions along the virtual track representing the desired path with the positions beginning from the start point to the end point including the velocities of each of the at least one segment. The waypoint file is sent to the robot for traversing along the virtual track.

Bruemmer, David J. (Idaho Falls, ID); Few, Douglas A. (Idaho Falls, ID); Walton, Miles C. (Idaho Falls, ID)

2011-07-05T23:59:59.000Z

264

Study of the performance of three micromixing models in transported scalar PDF simulations of a piloted jet diffusion flame ('Delft Flame III')  

SciTech Connect (OSTI)

Numerical simulation results are presented for a turbulent nonpremixed flame with local extinction and reignition. The transported scalar PDF approach is applied to the turbulence-chemistry interaction. The turbulent flow field is obtained with a nonlinear two-equation turbulence model. A C{sub 1} skeletal scheme is used as the chemistry model. The performance of three micromixing models is compared: the interaction by exchange with the mean model (IEM), the modified Curl's coalescence/dispersion model (CD) and the Euclidean minimum spanning tree model (EMST). With the IEM model, global extinction occurs. With the standard value of model constant C{sub f}=2, the CD model yields a lifted flame, unlike the experiments, while with the EMST model the correct flame shape is obtained. However, the conditional variances of the thermochemical quantities are underestimated with the EMST model, due to a lack of local extinction in the simulations. With the CD model, the flame becomes attached when either the value of C{sub f} is increased to 3 or the pilot flame thermal power is increased by a factor of 1.5. With increased value of C{sub f} better results for mixture fraction variance are obtained with both the CD and the EMST model. Lowering the value of C{sub f} leads to better predictions for mean temperature with EMST, but at the cost of stronger overprediction of mixture fraction variance. These trends are explained as a consequence of variance production by macroscopic inhomogeneity and the specific properties of the micromixing models. Local time stepping is applied so that convergence is obtained more quickly. Iteration averaging reduces statistical error so that the limited number of 50 particles per cell is sufficient to obtain accurate results. (author)

Merci, Bart [Department of Flow, Heat and Combustion Mechanics, Ghent University-UGent, B-9000 Ghent (Belgium); Roekaerts, Dirk [Department of Multi-Scale Physics, Delft University of Technology, Delft (Netherlands); Naud, Bertrand [CIEMAT, Madrid (Spain)

2006-02-01T23:59:59.000Z

265

A lattice Boltzmann algorithm for calculation of the laminar jet diffusion flame  

SciTech Connect (OSTI)

A new two-distribution lattice Boltzmann equation (LBE) algorithm is presented to solve the laminar diffusion flames within the context of Burke-Schumann flame sheet model. One distribution models the transport of the Schvab-Zeldovich coupling function, or the mixture fraction to combine the energy and species equations. The other distribution models the quasi-incompressible Navier-Stokes equations with the low Mach number approximation. In the quasi-incompressible flows, the thermodynamics quantities depend on the coupling function but not on the hydrodynamic pressure, and the fluid components are assumed to be compressible only in the mixing/reaction region. A systematic and consistent approach to deriving LBEs for the general advection-diffusion equation and the quasi-incompressible Navier-Stokes equations are also presented. The streaming step of the LBEs are discretized by the total variation diminishing (TVD) Lax-Wendroff scheme. Numerical simulations are carried out to reproduce the low frequency flame oscillation (or flame flicker) of buoyant jet diffusion flame. Comparison between the quasi-incompressible model and the incompressible model is presented and the role of non-solenoidal velocity is examined.

Lee, T. [Department of Mechanical and Industrial Engineering, IIHR - Hydroscience and Engineering, University of Iowa, Iowa City, IA 52242-1527 (United States)]. E-mail: thlee@ccny.cuny.edu; Lin, C.-L. [Department of Mechanical and Industrial Engineering, IIHR - Hydroscience and Engineering, University of Iowa, Iowa City, IA 52242-1527 (United States)]. E-mail: ching-long-lin@uiowa.edu; Chen, L.-D. [Department of Mechanical and Industrial Engineering, National Advanced Driving Simulator, University of Iowa, Iowa City, IA 52242-1527 (United States)]. E-mail: lea-der-chen@uiowa.edu

2006-06-10T23:59:59.000Z

266

Use of laser-induced ionization to detect soot inception in premixed flames  

SciTech Connect (OSTI)

Experimental measurements of laser-induced ionization were performed for ethene-air premixed flames operated near the soot inception point. Soot was ionized with a pulsed laser operated at 532 nm. The ionization signal was collected with a tungsten electrode located in the postflame region. Ionization signals were collected by use of both single-electrode and dual-electrode configurations. Earlier laser-induced- ionization studies focused on the use of a single biased electrode to generate the electric field, with the burner head serving as the path to ground. In many practical combustion systems, a path to ground is not readily available. To apply the laser-induced- ionization diagnostic to these geometries, a dual-electrode geometry must be employed. The influence of electrode configuration, flame equivalence ratio, and flame height on ionization signal detection was determined. The efficacy of the laser-induced-ionization diagnostic in detecting soot inception in the postflame region of a premixed flame by use of a dual-electrode configuration was investigated. Of the dual-electrode configurations tested, the dual-electrode geometry oriented parallel to the laser beam was observed to be most sensitive for detecting the soot inception point in a premixed flame.

Manzello, Samuel L.; Lee, Eui Ju; Mulholland, George W

2005-08-20T23:59:59.000Z

267

An Architecture for Managing Virtual Circuit and Virtual Path Services on ATM Networks  

E-Print Network [OSTI]

1 An Architecture for Managing Virtual Circuit and Virtual Path Services on ATM Networks Abstract management architecture that provides the services and is instrumented for network management purposes service monitor- ing and control functions. The network management architecture proposes complete managed

Columbia University

268

M AT E R I A L S S C I E N C E Making Flame  

E-Print Network [OSTI]

. The best materials showed heat resistance up to 400°C. All the materials tested had little residual charM AT E R I A L S S C I E N C E Making Flame Retardant Polymeric flame-retardant materials after heat- ing to 1200°C, indicating al- most complete decomposi- tion, and produced no toxic materials

Blower, Sally

269

Feature Article Negative pressure dependence of mass burning rates of H2/CO/O2/diluent flames  

E-Print Network [OSTI]

with predominantly CO, CO2, and H2O) as a fuel itself as synthetic gas or ``syngas" from coal or biomass gasification of burning rates, analysis of the key reactions and kinetic pathways, and modeling studies were performed and temperature dependence compared to Ar-diluted flames of the same flame temperature. Simulations were performed

Ju, Yiguang

270

Experimental Endeavour on a Pillar of Flame: Space Shuttle Rises with  

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

Experimental Endeavour on a Pillar of Flame: Space Shuttle Rises Experimental Endeavour on a Pillar of Flame: Space Shuttle Rises with Ambitious Technology Aboard Experimental Endeavour on a Pillar of Flame: Space Shuttle Rises with Ambitious Technology Aboard May 17, 2011 - 5:15pm Addthis Smoke cloud from Endeavour's Final Launge | Photo: NASA, Troy Cryder Smoke cloud from Endeavour's Final Launge | Photo: NASA, Troy Cryder Charles Rousseaux Charles Rousseaux Senior Writer, Office of Science What are the key facts? Space Shuttle Endeavour, which lifted off on its final mission Monday, carrying the Alpha Magnetic Spectrometer (AMS) experiment. In addition to measuring how cosmic rays flow and what they are made of, the AMS will also search for cosmic rays made of a special form of matter known as antimatter. By looking for new particles in space via the AMS, scientists might

271

Experimental Endeavour on a Pillar of Flame: Space Shuttle Rises with  

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

Experimental Endeavour on a Pillar of Flame: Space Shuttle Rises Experimental Endeavour on a Pillar of Flame: Space Shuttle Rises with Ambitious Technology Aboard Experimental Endeavour on a Pillar of Flame: Space Shuttle Rises with Ambitious Technology Aboard May 17, 2011 - 5:15pm Addthis Smoke cloud from Endeavour's Final Launge | Photo: NASA, Troy Cryder Smoke cloud from Endeavour's Final Launge | Photo: NASA, Troy Cryder Charles Rousseaux Charles Rousseaux Senior Writer, Office of Science What are the key facts? Space Shuttle Endeavour, which lifted off on its final mission Monday, carrying the Alpha Magnetic Spectrometer (AMS) experiment. In addition to measuring how cosmic rays flow and what they are made of, the AMS will also search for cosmic rays made of a special form of matter known as antimatter. By looking for new particles in space via the AMS, scientists might

272

Measurement of temperature distributions in large pool fires with the use of directional flame thermometers  

SciTech Connect (OSTI)

Temperatures inside the flame zone of large regulatory pool fires measured during tests of radioactive materials packages vary widely with both time and position. Measurements made with several Directional Flame Thermometers, in which a thermocouple is attached to a thin metal sheet that quickly approaches flame temperatures, have been used to construct fire temperature distributions and cumulative probability distributions. As an aid to computer simulations of these large fires, these distributions are presented. The distributions are constructed by sorting fire temperature data into bins 10 C wide. A typical fire temperature distribution curve has a gradual increase starting at about 600 C, with the number of observations increasing to a peak near 1000 C, followed by an abrupt decrease in frequency, with no temperatures observed above 1200 C.

KOSKI,JORMAN A.

2000-05-09T23:59:59.000Z

273

Detailed modeling and laser-induced fluorescence imaging of nitric oxide in a NH3-seeded non-premixed methane/air flame  

E-Print Network [OSTI]

non-premixed methane/air flame John B. Bell, Marcus S. Day, Joseph F. Grcar Computing Sciences-induced fluorescence imaging of nitric oxide in a NH3-seeded non-premixed methane/air flame Abstract In this paper we study the formation of NO in laminar, nitrogen diluted methane diffusion flames that are seeded

Bell, John B.

274

Laser-saturated fluorescence of nitric oxide and chemiluminescence measurements in premixed ethanol flames  

SciTech Connect (OSTI)

In this study, nitric oxide laser-saturated fluorescence (LSF) measurements were acquired from premixed ethanol flames at atmospheric pressure in a burner. NO-LSF experimental profiles for fuel-rich premixed ethanol flames ({phi} = 1.34 and {phi} = 1.66) were determined through the excitation/detection scheme of the Q{sub 2}(26.5) rotational line in the A{sup 2}{sigma}{sup +} - X{sup 2}{pi} (0,0) vibronic band and {gamma}(0,1) emission band. A calibration procedure by NO doping into the flame was applied to establish the NO concentration profiles in these flames. Chemiluminescent emission measurements in the (0, 0) vibronic emission bands of the OH{sup *} (A{sup 2}{sigma}{sup +} - X{sup 2}{pi}) and CH{sup *}(A{sup 2}{delta} - X{sup 2}{pi}) radicals were also obtained with high spatial and spectral resolution for fuel-rich premixed ethanol flames to correlate them with NO concentrations. Experimental chemiluminescence profiles and the ratios of the integrated areas under emission spectra (A{sub CH*}/A{sub CH*}(max.) and A{sub CH*}/A{sub OH*}) were determined. The relationships between chemiluminescence and NO concentrations were established along the premixed ethanol flames. There was a strong connection between CH{sup *} radical chemiluminescence and NO formation and the prompt-NO was identified as the governing mechanism for NO production. The results suggest the optimum ratio of the chemiluminescence of two radicals (A{sub CH*}/A{sub OH*}) for NO diagnostic purposes. (author)

Marques, Carla S.T.; Barreta, Luiz G.; Sbampato, Maria E.; dos Santos, Alberto M. [Aerothermodynamic and Hypersonic Division, Institute of Advanced Studies - General Command of Aerospatial Technology, Rodovia dos Tamoios, km 5.5, 12228-001 Sao Jose dos Campos - SP (Brazil)

2010-11-15T23:59:59.000Z

275

Mitigation of thermoacoustic instability utilizing steady air injection near the flame anchoring zone  

SciTech Connect (OSTI)

The objective of this work is to investigate the effectiveness of steady air injection near the flame anchoring zone in suppressing thermoacoustic instabilities driven by flame-vortex interaction mechanism. We perform a systematic experimental study which involves using two different configurations of air injection in an atmospheric pressure backward-facing step combustor. The first configuration utilizes a row of micro-diameter holes allowing for air injection in the cross-stream direction just upstream of the step. The second configuration utilizes an array of micro-diameter holes located on the face of the step, allowing for air injection in the streamwise direction. The effects of each of these configurations are analyzed to determine which one is more effective in suppressing thermoacoustic instabilities at different operating conditions. The tests are conducted while varying the equivalence ratio and the inlet temperature. The secondary air temperature is always the same as the inlet temperature. We used pure propane or propane/hydrogen mixtures as fuels. Combustion dynamics are explored through simultaneous pressure and heat release-rate measurements, and high-speed video images. When the equivalence ratio of the reactant mixture is high, it causes the flame to flashback towards the inlet channel. When air is injected in the cross-stream direction, the flame anchors slightly upstream of the step, which suppresses the instability. When air is injected in the streamwise direction near the edge of step, thermoacoustic instability could be eliminated at an optimum secondary air flow rate, which depends on the operating conditions. When effective, the streamwise air injection prevents the shedding of an unsteady vortex, thus eliminating the flame-vortex interaction mechanism and resulting in a compact, stable flame to form near the step. (author)

Murat Altay, H.; Hudgins, Duane E.; Speth, Raymond L.; Annaswamy, Anuradha M.; Ghoniem, Ahmed F. [Massachusetts Institute of Technology, Department of Mechanical Engineering, Cambridge, MA 02139 (United States)

2010-04-15T23:59:59.000Z

276

A laser and molecular beam mass spectrometer study of low-pressure dimethyl ether flames  

SciTech Connect (OSTI)

The oxidation of dimethyl ether (DME) is studied in low-pressure flames using new molecular beam mass spectrometer and laser diagnostics. Two 30.0-Torr, premixed DME/oxygen/argon flames are investigated with stoichiometries of 0.98 and 1.20. The height above burner profiles of nine stable species and two radicals are measured. These results are compared to the detailed chemical reaction mechanism of Curran and coworkers. Generally good agreement is found between the model and data. The largest discrepancies are found for the methyl radical profiles where the model predicts qualitatively different trends in the methyl concentration with stoichiometry than observed in the experiment.

Andrew McIlroy; Toby D. Hain; Hope A. Michelsen; Terrill A. Cool

2000-12-15T23:59:59.000Z

277

Reduction of Emissions from a Syngas Flame Using Micromixing and Dilution with CO2  

Science Journals Connector (OSTI)

Hydrogen-rich syngas can be burned stably in the designed combustor, and each suite of nozzles forms a flame surface. ... The smaller dilution ratio and the higher fuel heating value means the fuel can be burned quickly after it leaves the nozzles, resulting in strong heat release in the frontal section of the burner. ... There are, however, gaps in the fundamental understanding of syngas combustion and emissions, as most previous research has focused on flames burning individual fuel components such as H2 and CH4, rather than syngas mixts. ...

Yongsheng Zhang; Tianming Yang; Xueqi Liu; Long Tian; Zhongguang Fu; Kai Zhang

2012-10-25T23:59:59.000Z

278

Method for producing flame retardant porous products and products produced thereby  

DOE Patents [OSTI]

A method for fire retarding porous products used for thermal energy storage and products produced thereby is provided. The method includes treating the surface of the phase change material-containing porous products with a urea fire-retarding agent. Upon exposure to a flame, the urea forms an adduct with the phase change material which will not sustain combustion (is self-extinguishing) in air. No halogens or metal oxides are contained in the fire retardant, so no potentially noxious halide smoke or fumes are emitted if the product is continuously exposed to a flame. 1 fig.

Salyer, I.O.

1998-08-04T23:59:59.000Z

279

Method for producing flame retardant porous products and products produced thereby  

DOE Patents [OSTI]

A method for fire retarding porous products used for thermal energy storage and products produced thereby is provided. The method includes treating the surface of the phase change material-containing porous products with a urea fire-retarding agent. Upon exposure to a flame, the urea forms an adduct with the phase change material which will not sustain combustion (is self-extinguishing) in air. No halogens or metal oxides are contained in the fire retardant, so no potentially noxious halide smoke or fumes are emitted if the product is continuously exposed to a flame.

Salyer, Ival O. (Dayton, OH)

1998-08-04T23:59:59.000Z

280

Method for Producing Flame Retardant Porous Products and Products Produced Thereby  

DOE Patents [OSTI]

A method for fire retarding porous products used for thermal energy storage and products produced thereby is provided. The method includes treating the surface of the phase change material-containing porous products with a urea fire-retarding agent. Upon exposure to a flame, the urea forms an adduct with the phase change material which will not sustain combustion (is self-extinguishing) in air. No halogens or metal oxides are contained in the fire retardant, so no potentially noxious halide smoke or fumes are emitted if the product is continuously exposed to a flame.

Salyer, Ival O. (Dayton, OH)

1998-08-04T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Comparison of the combustion behavior of Orimulsion{trademark} and heavy fuel oil in 70 MW flames  

SciTech Connect (OSTI)

Results of an experimental study are shown in this publication to compare the combustion behavior of heavy fuel oil (HFO) and Orimulsion in 70 MW flames. The investigation was carried out with the use of the combustion test rig at the International Combustion Limited in Derby, UK. The main objective of this test work was to quantify the extent of differences in flame properties, particulate and gaseous emissions of Orimulsion and HFO. Under identical combustion conditions, axial profiles of flame temperature and radiation heat flux were determined at 70 MW thermal input and 1% O{sub 2} for both fuels. Gas compositions at flame tail and furnace exit were obtained to estimate flame length and emission of gaseous pollutants. Stack concentration, carbon content, size and chemical composition of fly ash were also measured. The effect of excess air level on exit NOx and CO concentration were studied. Results of detailed flame measurements and the parametric study have shown that orimulsion fuel can be burnt with 99.97% efficiency at 1% exit O{sub 2} with a modified burner system of Dunamenti Power Station. However, significant implications of Orimulsion firing were observed. Gas temperature data and CO concentrations at flame tail have indicated a 1.5--2 m longer flame for Orimulsion. At flame tail, gas temperature in the Orimulsion flame was higher by 100 C than that for HFO. Lower radiant heat flux was measured in the near burner region for Orimulsion. Higher SO{sub 3}, SO{sub 2} and lower NOx emission were found when firing Orimulsion. Despite the higher ash content of Orimulsion, its combustion resulted in smaller particulate emission, which might be due to fly ash deposition in the furnace.

Barta, L.E. [Inst. for Energy, Budapest (Hungary); Horvath, G. [Hungarian Power Companies, Ltd., Budapest (Hungary); Allen, J.W.; Darar, J.S.; Wright, J.A. [International Combustion Ltd., Derby (United Kingdom). Rolls Royce Industrial Power Group; Szederkenyi, S.

1996-12-31T23:59:59.000Z

282

Architectural Lighting Analysis in Virtual Lighting Laboratory  

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

Architectural Lighting Analysis in Virtual Lighting Laboratory Architectural Lighting Analysis in Virtual Lighting Laboratory Speaker(s): Mehlika Inanici Date: July 7, 2003 - 12:00pm Location: Bldg. 90 Seminar Host/Point of Contact: Satkartar K. Kinney Virtual Lighting Laboratory is a Radiance-based lighting analysis tool and methodology that proposes transformations in the utilization of computer visualization in lighting analysis and design decision-making. It is a computer environment, where the user has been provided with matrices of illuminance and luminance values extracted from high dynamic range images. The principal idea is to provide the laboratory to the designer and researcher to explore various lighting analysis techniques instead of imposing limited number of predetermined metrics. In addition, it introduces an analysis approach for temporal and spatial lighting

283

Ion mobility spectrometer with virtual aperture grid  

DOE Patents [OSTI]

An ion mobility spectrometer does not require a physical aperture grid to prevent premature ion detector response. The last electrodes adjacent to the ion collector (typically the last four or five) have an electrode pitch that is less than the width of the ion swarm and each of the adjacent electrodes is connected to a source of free charge, thereby providing a virtual aperture grid at the end of the drift region that shields the ion collector from the mirror current of the approaching ion swarm. The virtual aperture grid is less complex in assembly and function and is less sensitive to vibrations than the physical aperture grid.

Pfeifer, Kent B. (Los Lunas, NM); Rumpf, Arthur N. (Albuquerque, NM)

2010-11-23T23:59:59.000Z

284

TEAM COLLABORATION IN VIRTUAL WORLDS: THE ROLE OF TASK COMPLEXITY.  

E-Print Network [OSTI]

??Virtual worlds are three-dimensional, computer-generated worlds where team collaboration can be facilitated through the use of shared virtual space and mediated using avatars. In this… (more)

Sattayanuwat, Parichart

2011-01-01T23:59:59.000Z

285

Flame-driven deflagration-to-detonation transitions in Type Ia supernovae?  

E-Print Network [OSTI]

Although delayed detonation models of thermonuclear explosions of white dwarfs seem promising for reproducing Type Ia supernovae, the transition of the flame propagation mode from subsonic deflagration to supersonic detonation remains hypothetical. A potential instant for this transition to occur is the onset of the distributed burning regime, i.e. the moment when turbulence first affects the internal flame structure. Some studies of the burning microphysics indicate that a deflagration-to-detonation transition may be possible here, provided the turbulent intensities are strong enough. Consequently, the magnitude of turbulent velocity fluctuations generated by the deflagration flame is analyzed at the onset of the distributed burning regime in several three-dimensional simulations of deflagrations in thermonuclear supernovae. It is shown that the corresponding probability density functions fall off towards high turbulent velocity fluctuations much more slowly than a Gaussian distribution. Thus, values claimed to be necessary for triggering a detonation are likely to be found in sufficiently large patches of the flame. Although the microphysical evolution of the burning is not followed and a successful deflagration-to-detonation transition cannot be guaranteed from simulations presented here, the results still indicate that such events may be possible in Type Ia supernova explosions.

F. K. Roepke

2007-09-26T23:59:59.000Z

286

Heat Transfer from Augmented Flames and Plasma Jets Based on Magnetically Rotated Arcs  

Science Journals Connector (OSTI)

...November 1971 research-article Heat Transfer from Augmented Flames and Plasma...Jones F. J. Weinberg Rates of heat transfer to the inner surface of a surrounding...experimental data on a computer to yield heat transfer coefficients is developed on this...

1971-01-01T23:59:59.000Z

287

Carbon nanotubes grow in combustion flames Issued on March 31, 2014  

E-Print Network [OSTI]

Carbon nanotubes grow in combustion flames Issued on March 31, 2014 Quantum chemical simulations reveal an unprecedented relationship between the mechanism of carbon nanotube growth and hydrocarbon of carbon nanotube (CNT) growth and hydrocarbon combustion actually share many similarities. In studies

Takahashi, Ryo

288

Visualization of Turbulent Flame Fronts with Planar Laser-Induced Fluorescence  

Science Journals Connector (OSTI)

...TWO-DIMENSIONAL GAS CONCENTRATION MEASUREMENTS...flames at atmospheric pressure. More-over, the...carried out at constant pressure and the molecular...win-dows in the combustor. A simple fused...because ofthe often high and rapid-ly fluctuating...made it an ideal natural laboratory for the...

GEORGE KYCHAKOFF; ROBERT D. HOWE; RONALD K. HANSON; MICHAEL C. DRAKE; ROBERT W. PITZ; MARSHALL LAPP; C. MURRAY PENNEY

1984-04-27T23:59:59.000Z

289

Advancing predictive models for particulate formation in turbulent flames via massively parallel direct numerical simulations  

Science Journals Connector (OSTI)

...147. The pressure is atmospheric. The gas-phase hydrodynamics...formulation is the high-order inter...aeroderivative combustors, while the...fraction is highest (figure-4...scavenging gas-phase precursors...flame of natural gas and air...based on the high Da number...

2014-01-01T23:59:59.000Z

290

VisionGuided Flame Control Using Fuzzy Logic and Neural Networks  

E-Print Network [OSTI]

of the combustion processes are not amenable to mathematical modeling based on simple physical and chemical laws to a vision­guided closed loop control for stationary luminous flames. The image processing technique is used automatically. 2 #12; 1 Introduction Combustion, as one of the most important industrial processes, is a very

291

Synthesis of carbon nanotubes on metal alloy substrates with voltage bias in methane inverse diffusion flames  

E-Print Network [OSTI]

of the hydrocarbon fuel intrinsically provides not only the source of process heat to establish the requisite; Catalytically grown carbon; Combustion; Raman spectroscopy 1. Introduction Since IijimaÃ?s discovery [1] of CNTs-volume production, without the need for expensive starting materi- als. In flame synthesis, combustion

Tse, Stephen D.

292

Numerical simulation of Lewis number effects on lean premixed turbulent flames  

E-Print Network [OSTI]

turbulent flames for lean hydrogen, propane and methane mixtures in two dimensions. Each simulation or syngas, obtained from coal gasification, has sparked interest in the development of burners that can for propane, methane and hydrogen using de- tailed chemistry and transport, corresponding to Le > 1, Le 1

293

PHYSICAL REVIEW E 86, 036314 (2012) ac electric fields drive steady flows in flames  

E-Print Network [OSTI]

PHYSICAL REVIEW E 86, 036314 (2012) ac electric fields drive steady flows in flames Aaron M. Drews June 2012; published 20 September 2012) We show that time-oscillating electric fields applied-averaged force that drives the steady flows observed experimentally. A quantitative model describes the response

Heller, Eric

294

A combined computational and experimental characterization of lean premixed turbulent low swirl laboratory flames.  

E-Print Network [OSTI]

of these alternate fuels will vary significantly with the type of feedstocks and their treatment processes , Vince Beckner1 and Robert Cheng3 , 1 Center for Computational Sciences and Engineering, Lawrence, and then use the simulation data to further probe the time-dependent, 3D structure of the flames

Bell, John B.

295

Cellular burning in lean premixed turbulent hydrogen-air flames: coupling experimental and  

E-Print Network [OSTI]

of burners, particularly for alternative fuels, depends on improving our understanding of basic flame. Beckner1, M. J. Lijewski1 1 Center for Computational Science and Engineering, Lawrence Berkeley National for burning the fuel-lean mixtures of hydrogen or hydrogen-rich syngas fuels obtained from the gasification

296

Strategies for laser-induced fluorescence detection of nitric oxide in high-pressure flames.  

E-Print Network [OSTI]

engines and gas turbines where the combustion chamber is at high pressure. Despite the use of catalyticStrategies for laser-induced fluorescence detection of nitric oxide in high-pressure flames. II. A combustion systems3�13 and thus develop new schemes to mini- mize NO effluent. The high operating pressure

Lee, Tonghun

297

Copyright 2007 by ASME1 Laminar Flame Speeds and Strain Sensitivities of Mixtures of H2  

E-Print Network [OSTI]

to rich. [Keywords: Syngas, laminar flame speed, reactant preheat, CO2 dilution, N2 dilution] INTRODUCTION Technologies such as integrated gasification combined cycle (IGCC) plants enable combustion of coal, biomass emissions. Synthetic gas (syngas) fuels derived from coal are particularly promising in this regard. Syngas

Seitzman, Jerry M.

298

EFFECT OF FUEL TYPE ON FLAME IGNITION BY TRANSIENT PLASMA Jianbang Liu1,2  

E-Print Network [OSTI]

to electrical energy consumed to produce the discharge.) Consequently, ignition by laser sources has beenEFFECT OF FUEL TYPE ON FLAME IGNITION BY TRANSIENT PLASMA DISCHARGES Jianbang Liu1,2 , Fei Wang1 with air ignited by transient plasma discharge were investigated and compared with spark discharge ignition

299

Flame Front Matching and Tracking in PLIF Images Using Geodesic Paths and Level Sets  

E-Print Network [OSTI]

. Successive images of the combustion process captured in controlled experiments are smoothed by non combustion processes of varying types and turbulence levels. The local intensity in the recorded images) imaging of OH radicals in combustion processes. The data includes both premixed flames subjected

Hamarneh, Ghassan

300

Combustion and Flame 151 (2007) 235244 www.elsevier.com/locate/combustflame  

E-Print Network [OSTI]

Combustion and Flame 151 (2007) 235­244 www.elsevier.com/locate/combustflame Effect of ethanol Available online 26 July 2007 Abstract The effect of fuel-side ethanol addition on the chemical structure of average structural parameters. The results indicate that the ethanol effect on the aromatic components

Utah, University of

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Soot formation in aerodynamically strained methane-air and ethylene-air diffusion flames with chloromethane addition  

SciTech Connect (OSTI)

The effects of chloromethane (CH{sub 3}Cl) addition on soot inception in methane-air and ethylene-air counterflow diffusion flames were investigated by varying the concentrations of chloromethane and nitrogen in the fuel stream. Experiments showed a monotonic increase in the critical sooting stretch rate for methane-air flames when methane was replaced by chloromethane, while ethylene and chloromethane flames exhibited a larger sooting tendency than flames under comparable conditions and burning either ethylene or chloromethane alone. For the conditions investigated, the critical sooting stretch rates of methane-chloromethane-nitrogen flames were shown to be primarily a function of the chloromethane loading in the fuel stream. The structure of these flames was modeled using detailed chemistry and transport. Modeling results suggested that the enhancement of soot formation in ethylene-chloromethane flames may be a combined result of increased concentrations of C{sub 2} species and chlorinated C{sub 1} radicals (CH{sub 2}Cl and CHCl). A large rate of the reactions among these species may be the first steps in the molecular growth processes, which leads to the inception of soot particles. (author)

Leylegian, J.C. [ATK GASL NY Operations, 77 Raynor Avenue, Ronkonkoma, NY 11779-6648 (United States)

2008-01-15T23:59:59.000Z

302

Stabilization of liquid hydrocarbon fuel combustion by using a programmable microwave discharge in a subsonic airflow  

SciTech Connect (OSTI)

Under conditions of a programmable discharge (a surface microwave discharge combined with a dc discharge), plasma-enhanced combustion of alcohol injected into a subsonic (M = 0.3-0.9) airflow in the drop (spray) phase is stabilized. It is shown that the appearance of the discharge, its current-voltage characteristic, the emission spectrum, the total emission intensity, the heat flux, the electron density, the hydroxyl emission intensity, and the time dependences of the discharge current and especially discharge voltage change substantially during the transition from the airflow discharge to stabilized combustion of the liquid hydrocarbon fuel. After combustion stabilization, more than 80% of liquid alcohol can burn out, depending on the input power, and the flame temperature reaches {approx}2000 K.

Kopyl, P. V.; Surkont, O. S.; Shibkov, V. M.; Shibkova, L. V. [Moscow State University, Faculty of Physics (Russian Federation)

2012-06-15T23:59:59.000Z

303

Feedback stabilization initiative  

SciTech Connect (OSTI)

Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes.

NONE

1997-06-01T23:59:59.000Z

304

RCRA facility stabilization initiative  

SciTech Connect (OSTI)

The RCRA Facility Stabilization Initiative was developed as a means of implementing the Corrective Action Program`s management goals recommended by the RIS for stabilizing actual or imminent releases from solid waste management units that threaten human health and the environment. The overall goal of stabilization is to, as situations warrant, control or abate threats to human health and/or the environment from releases at RCRA facilities, and/or to prevent or minimize the further spread of contamination while long-term remedies are pursued. The Stabilization initiative is a management philosophy and should not be confused with stabilization technologies.

Not Available

1995-02-01T23:59:59.000Z

305

The application of virtual reality in astronomy education  

Science Journals Connector (OSTI)

In this paper, we study the virtual reality technologies for developing a virtual astronomical museum, which can be applied in astronomy education. The museum contains four exhibition areas of the following topics: Astronomy Technologies, the Moon ... Keywords: astronomy education, internet, virtual reality, web-based learning

W. Tarng; H. Liou

2007-06-01T23:59:59.000Z

306

Virtual bidding: the good, the bad and the ugly  

SciTech Connect (OSTI)

Virtual bidding has become an integral part of major organized electricity markets in the U.S. over the last decade; in some markets, virtual bids set the price half the time. Although virtual bidding can enhance the efficiency of electricity markets, that does not come without risk. (author)

Celebi, Metin; Hajos, Attila; Hanser, Philip Q

2010-06-15T23:59:59.000Z

307

CyberWalk: Enabling unconstrained omnidirectional walking through virtual environments  

Science Journals Connector (OSTI)

Despite many recent developments in virtual reality, an effective locomotion interface which allows for normal walking through large virtual environments was until recently still lacking. Here, we describe the new CyberWalk omnidirectional treadmill ... Keywords: Virtual reality, control system, locomotion, spatial navigation, treadmill

J. L. Souman; P. Robuffo Giordano; M. Schwaiger; I. Frissen; T. Thümmel; H. Ulbrich; A. De Luca; H. H. Bülthoff; M. O. Ernst

2011-11-01T23:59:59.000Z

308

Technical Documentation for System Center 2012 Virtual Machine  

E-Print Network [OSTI]

#12; Technical Documentation for System Center 2012 ­ Virtual Machine Manager VMM Information Experience Team Summary: Virtual Machine Manager (VMM) is a management solution resources in order to create and deploy virtual machines and services to private clouds that you have

Hunt, Galen

309

System/370 Extended Architecture: Facilities for Virtual Machines  

E-Print Network [OSTI]

p. H. Gum System/370 Extended Architecture: Facilities for Virtual Machines This paper describes the evolution of facilities for virtual machines on IBM System/370 computers, and presents the elements of a new architectural facility designed for the virtual-machine environment. Assists that have been added to various

Yang, Junfeng

310

DBA-VM: Dynamic Bandwidth Allocator for Virtual Machines  

E-Print Network [OSTI]

DBA-VM: Dynamic Bandwidth Allocator for Virtual Machines Ahmed Amamou, Manel Bourguiba, Kamel for Virtual Machines with regard to the established SLAs. The proposed scheme enforces the isolation between the virtual machines through the transmission bandwidth adjustment at the network I/O channel

Paris-Sud XI, Université de

311

THE DERIVED SERIES AND VIRTUAL BETTI NUMBERS SIDDHARTHA GADGIL  

E-Print Network [OSTI]

THE DERIVED SERIES AND VIRTUAL BETTI NUMBERS SIDDHARTHA GADGIL Abstract. The virtual Betti number conjecture states that any hyperbolic three-manifold has a finite cover with positive first Betti number. We that the virtual Betti number conjecture would follow if it were known that the derived series of the fundamental

Gadgil, Siddhartha

312

Computer Games and Virtual Worlds: New Modalities of  

E-Print Network [OSTI]

Institute for Software Research and Center for Computer Games and Virtual Worlds University of California;13 "Gowning" training game, developed at UCI GameLab #12;14 Game-based tele-rehabilitation #12;15 · Virtual, collaborative product/prototype development, and more Game-based virtual worlds and tele-rehabilitation #12

Scacchi, Walt

313

Analyzing and Improving MPI Communication Performance in Overcommitted Virtualized Systems  

Science Journals Connector (OSTI)

Nowadays, it is an important trend in the system domain to use the software-based virtualization technology to build the execution environments (e.g., Clouds) and serve high performance computing (HPC) applications. However, with the extra virtualization ... Keywords: virtualization, cloud, MPI, performance

Zhiyuan Shao; Qiang Wang; Xuejiao Xie; Hai Jin; Ligang He

2011-07-01T23:59:59.000Z

314

A virtual experiment platform for mechanism motion cognitive learning  

Science Journals Connector (OSTI)

In order to give students a more intuitionistic understanding in mechanism motion system, a virtual experiment platform is designed and developed. First, experimental component models, which contain both visual information and logical information, are ... Keywords: mechanism motion experiment, modelica modeling, virtual experiment, virtual reality

Xiumin Fan; Xi Zhang; Huangchong Cheng; Yanjun Ma; Qichang He

2011-07-01T23:59:59.000Z

315

Virtual reality and hybrid technology for neurorehabilitations  

Science Journals Connector (OSTI)

Disabilities that follow Cerebrovascular accidents (CVA) and spinal cord injuries (SCI) severely impair motor functions and thereby prevent the affected individuals from full and autonomous participation in daily activities. Several studies have shown ... Keywords: brain neuro-machine interface, cerebrovascular accidents, motor-neuroprosthetics, neuro-robotics, spinal cord injury, virtual reality

Alessandro De Mauro; Aitor Ardanza; Chao Chen; Eduardo Carrasco; David Oyarzun; Diego Torricelli; Shabs Rajasekharan; Josè Luis Pons; Ángel Gil-Agudo; Julián Flórez Esnal

2007-06-01T23:59:59.000Z

316

Two Approaches to Facilitate Virtual Lab Implementation  

Science Journals Connector (OSTI)

Here two software tools are presented that facilitate virtual lab implementation: Interactive and Rand Model Designer. Interactive is a free Modelica library that's used in combination with the Dymola modeling environment. Rand Model Designer supports Model Vision Language an object-oriented modeling language based on the Unified Modeling Language (UML).

Carla Martín-Villalba; Alfonso Urquía; Yuri Senichenkov; Yuri Kolesov

2014-01-01T23:59:59.000Z

317

The `Virtual Hand' of Jihad Terrorism Monitor  

E-Print Network [OSTI]

The `Virtual Hand' of Jihad Terrorism Monitor Terrorism Focus Spotlight on Terror By Vol does Islam per se or "Muslim civilization" really have anything to do with terrorism ­ no more than massacre of 58 tourists http://www.jamestown.org/terrorism/news/article.php?articleid=2369701 (1 of 5) [5

Paris-Sud XI, Université de

318

Building Virtual Worlds: A City Planning Perspective  

E-Print Network [OSTI]

to the internet and the application of internet technologies in private company `intranets.' The obvious result.ingram@cs.nott.ac.uk Computing, networking and virtual reality technologies are gradually approaching the level of maturity where The relentless expansion of computing technology into our workplaces and homes in the past 15­20 years is plain

Bowden, Richard

319

Oorange: A Virtual Laboratory for Experimental Mathematics  

E-Print Network [OSTI]

organized as a virtual laboratory, which presents a uni ed user interface integrating all the above- jects Monitor and control: Object inspection; 2D and 3D viewers Running the experiment: Animation objects Recording the experiment: Archiving and scripting Disseminating result: Documentation A hybrid

Polthier, Konrad

320

OS Support for Virtualizing Hardware Transactional Memory  

E-Print Network [OSTI]

the problem and abort transactions on a virtualization event. This mechanism is simple, fast, and effec- tive on physical addresses. We propose an extension to LogTM-SE, called LogTM-VSE, that addresses these problems that voluntarily context switches. However, we find that abort- ing a transaction is generally faster than

Wood, David A.

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Stability analysis of multi-phase AC arc discharge for in-flight glass melting  

Science Journals Connector (OSTI)

A stable multi-phase AC arc was generated to by transformers at a commercial electric system. The arc discharge behavior and the stability were investigated by the high-speed video camera observation synchronized with the voltage waveform analysis. The effect of the number of phase and the flaming gas addition into the arc region on the arc behavior and the arc stability were studied. Results showed that the re-ignition occurred between adjacent electrodes periodically. Two kinds of the stability analysis methods were introduced. The estimated fluctuation degree showed that an increase of the number of the phase leads to the stable multi-phase AC arc. The deviation of the arc voltage from the average arc voltage was estimated to evaluate the uniformity of the multi-phase AC arc. Although an addition of the oxygen flame into the arc region leads to lower uniformity, the modification of the electrode position can improve the uniformity of the multi-phase AC arc.

Manabu Tanaka; Yosuke Tsuruoka; Yaping Liu; Tsugio Matsuura; Takayuki Watanabe

2011-01-01T23:59:59.000Z

322

Apparatus and method for stabilization or oxidation of polymeric materials  

DOE Patents [OSTI]

An apparatus for treating polymeric materials comprises a treatment chamber adapted to maintain a selected atmosphere at a selected temperature; a means for supporting the polymeric material within the chamber; and, a source of ozone-containing gas, which decomposes at the selected temperature yielding at least one reactive oxidative species whereby the polymer is stabilized and cross linked through exposure to the oxidative species in the chamber at the selected temperature. The ozone may be generated by a plasma discharge or by various chemical processes. The apparatus may be configured for either batch-type or continuous-type processing. The apparatus and method are especially useful for preparing polymer fibers, particularly PAN fibers, for later carbonization treatments as well as to make flame-retardant fabrics.

Paulauskas, Felix L. (Knoxville, TN) [Knoxville, TN; Sherman, Daniel M. (Knoxville, TN) [Knoxville, TN

2010-01-19T23:59:59.000Z

323

February 13, 2008 Virtualized Environments for the Harness High Performance Computing Workbench 1/17 Virtualized Environments for the Harness  

E-Print Network [OSTI]

February 13, 2008 Virtualized Environments for the Harness High Performance Computing Workbench 1/17 Virtualized Environments for the Harness High Performance Computing Workbench Björn Könning1,2, Christian Virtualized Environments for the Harness High Performance Computing Workbench 4/17 Harness HPC Workbench

Engelmann, Christian

324

Experimental Study on the Basic Phenomena of Flame Stabilization Mechanism in a Porous Burner for Premixed Combustion Application  

Science Journals Connector (OSTI)

This was the driving force for investigation of porous burner application in exothermic thermal partial oxidation (POX) for production of syngas feed for MCFCs (Molten Carbonate Fuel Cells) and SOFCs (Solid Oxide Fuel Cells)(13) or for combustion of low calorific gases from landfills and waste pyrolysis. ... Although, due to the different maximal operational temperatures of the sponges it was not possible to perform all the investigations for the same set of conditions, a comparison between different burners can be made for the overlapping areas of the stable burning regions. ... Porous burners for lean-burn applications ...

Neda Djordjevic; Peter Habisreuther; Nikolaos Zarzalis

2012-10-18T23:59:59.000Z

325

Combustion analysis of an equimolar mixture of methane and syngas in a surface-stabilized combustion burner for household appliances  

Science Journals Connector (OSTI)

Abstract The primary objective of this work is to study the combustion of an equimolar mixture of methane and syngas (CH4–SG) in a ceramic surface-stabilized combustion burner. We examine the effects of the fuel composition, the air-to-fuel ratio and the thermal input on the flame stability, the radiation efficiency and the pollutant emissions (CO and NOx). In this study, we evaluate a syngas with a high hydrogen content that is similar to those obtained by coal gasification (50–60% H2) using Sasol/Lurgi gasification technology and biomass gasification, for example. To determine the effect of the air-to-fuel ratio (?), the burner performance is analyzed at ? = 1.4 and ? = 1.1. Some studies have reported optimal operating conditions for ? = 1.4, whereas for hydrocarbons, the proximity to stoichiometric conditions at the ? = 1.1 air-to-fuel ratio produces the highest possible laminar burning velocity and flame temperature. The thermal inputs evaluated in this study correspond to three values (1.0, 1.8, and 2.5 kW) found in household appliances and for cooking appliances in particular. The results for this experimental burner design indicate that the macroscopic flame shape for an equimolar CH4–SG mixture is approximately the same as that for CH4. Moreover, the pollutant concentrations in the flue gas are generally below 85 ppm for CO and 15 ppm for NOx. However, the thermal input and the air-to-fuel ratio significantly affect the flame structure, the radiation efficiency and the pollutant emissions.

Carlos E. Arrieta; Andrés A. Amell

2014-01-01T23:59:59.000Z

326

Ignition of Deflagration and Detonation Ahead of the Flame due to Radiative Preheating of Suspended Micro Particles  

E-Print Network [OSTI]

We study a flame propagating in the gaseous combustible mixture with suspended inert solid micro particles. The gaseous mixture is assumed to be transparent for thermal radiation emitted by the hot combustion products, while particles absorb and reemit the radiation. Thermal radiation heats the particles, which in turn transfer the heat to the surrounding unburned gaseous mixture by means of thermal heat transfer. Different scenarios are possible depending on the spatial distribution of the particles, their size and the number density. In the case of uniform spatial distribution the radiation absorption ahead of the flame causes a modest increase of the combustion wave velocity. On the contrary, in the case of non-uniform distribution of the particles, such that the particles number density increases far ahead of the flame, the preheating caused by the thermal radiation may trigger additional source of ignition. Far enough ahead of the flame, where number density of particles is higher, the temperature due to...

Ivanov, M F; Liberman, M A

2014-01-01T23:59:59.000Z

327

A study of the phenomenon of liquid-flame combustion; I. Visual examinations and high-speed photography  

SciTech Connect (OSTI)

A liquid-flame combustion phenomenon, which has been revealed for pressed mixtures of tetrazole and sodium tetrazolate, was studied using high-speed photography and photography of high spatial resolution. New, previously unknown, peculiarities of the origin and development of the liquid-flame structure, pertinent, in particular, to its external texture and interaction with the melt on the pellet surface, as well as some features of the dispersion of condensed products were found.

Astashinsky, V.M.; Kostyukevich, E.A. (Byelorussian Academy of Science, Minsk (Belarus). Inst. of Molecular and Atomic Physics); Ivashkevich, O.A.; Lesnikovich, A.I.; Krasitsky, V.A. (Byelorussian State Univ., Minsk (Belarus))

1994-02-01T23:59:59.000Z

328

Evolution of soot size distribution in premixed ethylene/air and ethylene/benzene/air flames: Experimental and modeling study  

SciTech Connect (OSTI)

The effect of benzene concentration in the initial fuel on the evolution of soot size distribution in ethylene/air and ethylene/benzene/air flat flames was characterized by experimental measurements and model predictions of size and number concentration within the flames. Experimentally, a scanning mobility particle sizer was used to allow spatially resolved and online measurements of particle concentration and sizes in the nanometer-size range. The model couples a detailed kinetic scheme with a discrete-sectional approach to follow the transition from gas-phase to nascent particles and their coagulation to larger soot particles. The evolution of soot size distribution (experimental and modeled) in pure ethylene and ethylene flames doped with benzene showed a typical nucleation-sized (since particles do not actually nucleate in the classical sense particle inception is often used in place of nucleation) mode close to the burner surface, and a bimodal behavior at greater height above burner (HAB). However, major features were distinguished between the data sets. The growth of nucleation and agglomeration-sized particles was faster for ethylene/benzene/air flames, evidenced by the earlier presence of bimodality in these flames. The most significant changes in size distribution were attributed to an increase in benzene concentration in the initial fuel. However, these changes were more evident for high temperature flames. In agreement with the experimental data, the model also predicted the decrease of nucleation-sized particles in the postflame region for ethylene flames doped with benzene. This behavior was associated with the decrease of soot precursors after the main oxidation zone of the flames. (author)

Echavarria, Carlos A.; Sarofim, Adel F.; Lighty, JoAnn S. [Department of Chemical Engineering, University of Utah, Salt Lake City, UT (United States); D'Anna, Andrea [Dipartimento di Ingegneria Chimica, Universita ''Federico II'' di Napoli, Naples (Italy)

2011-01-15T23:59:59.000Z

329

Controlled entanglement routing between two virtual pathways  

E-Print Network [OSTI]

We demonstrate controlled entanglement routing between bunching and antibunching path-entangled two-photon states in an unbalanced Mach-Zehnder interferometer (UMZI), in which the routing process is controlled by the relative phase difference in the UMZI. Regarding bunching and antibunching path-entangled two-photon states as two virtual ports, we can consider the UMZI as a controlled entanglement router, which bases on the coherent manipulation of entanglement. Half of the entanglement within the input two-photon state is coherently routed between the two virtual ports, while the other is lost due to the time distinguishability introduced by the UMZI. Pure bunching or antibunching path entangled two-photon states are obtained based on this controlled entanglement router. The results show that we can employ the UMZI as general entanglement router for practical quantum information application.

Qiang Zhou; Shuai Dong; Wei Zhang; Lixing You; Yuhao He; Weijun Zhang; Yidong Huang; Jiangde Peng

2014-07-16T23:59:59.000Z

330

Exploiting Virtualization and Cloud Computing in ATLAS  

E-Print Network [OSTI]

The ATLAS Computing Model was designed around the concept of grid computing; since the start of data-taking, this model has proven very successful in the federated operation of more than one hundred Worldwide LHC Computing Grid (WLCG) sites for offline data distribution, storage, processing and analysis. However, new paradigms in computing, namely virtualization and cloud computing, present improved strategies for managing and provisioning IT resources that could allow ATLAS to more flexibly adapt and scale its storage and processing workloads on varied underlying resources. In particular, ATLAS is developing a "grid-of-clouds" infrastructure in order to utilize WLCG sites that make resources available via a cloud API. This work will present the current status of the Virtualization and Cloud Computing R&D project in ATLAS Distributed Computing. First, strategies for deploying PanDA queues on cloud sites will be discussed, including the introduction of a "cloud factory" for managing cloud VM instances. Nex...

Barreiro Megino, FH; The ATLAS collaboration; De, K; Gable, I; Hendrix, V; Panitkin, S; Paterson, M; De Silva, A; van der Ster, D; Taylor, R; Vitillo, RA; Walker, R

2012-01-01T23:59:59.000Z

331

Detecting insider activity using enhanced directory virtualization.  

SciTech Connect (OSTI)

Insider threats often target authentication and access control systems, which are frequently based on directory services. Detecting these threats is challenging, because malicious users with the technical ability to modify these structures often have sufficient knowledge and expertise to conceal unauthorized activity. The use of directory virtualization to monitor various systems across an enterprise can be a valuable tool for detecting insider activity. The addition of a policy engine to directory virtualization services enhances monitoring capabilities by allowing greater flexibility in analyzing changes for malicious intent. The resulting architecture is a system-based approach, where the relationships and dependencies between data sources and directory services are used to detect an insider threat, rather than simply relying on point solutions. This paper presents such an architecture in detail, including a description of implementation results.

Shin, Dongwan (New Mexico Tech, Socorro, NM); Claycomb, William R.

2010-07-01T23:59:59.000Z

332

3D Spectroscopy and the Virtual Observatory  

E-Print Network [OSTI]

Integral field, or 3D, spectroscopy is the technique of obtaining spectral information over a two-dimensional, hopefully contiguous, field of view. While there is some form of astronomical 3D spectroscopy at all wavelengths, there has been a rapid increase in interest in optical and near-infrared 3D spectroscopy. This has resulted in the deployment of a large variety of integral-field spectrographs on most of the large optical/infrared telescopes. The amount of IFU data available in observatory archives is large and growing rapidly. The complications of treating IFU data as both imaging and spectroscopy make it a special challenge for the virtual observatory. This article describes the various techniques of optical and near-infrared spectroscopy and some of the general needs and issues related to the handling of 3D data by the virtual observatory.

Bryan W. Miller

2007-08-15T23:59:59.000Z

333

Virtual Hydropower Prospector | Open Energy Information  

Open Energy Info (EERE)

Virtual Hydropower Prospector Virtual Hydropower Prospector Jump to: navigation, search Tool Summary LAUNCH TOOL Name: Virtual Hydropower Prospector Agency/Company /Organization: Idaho National Laboratory Sector: Energy Topics: Resource assessment Resource Type: Software/modeling tools User Interface: Website Website: hydropower.inl.gov/prospector/index.shtml Country: United States Cost: Free Northern America Coordinates: 37.09024°, -95.712891° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":37.09024,"lon":-95.712891,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

334

Three-dimensional simulations of cellular non-premixed jet flames  

SciTech Connect (OSTI)

The formation, dynamics and structure of cellular flames in circular non-premixed jets are examined with three-dimensional numerical simulations incorporating detailed descriptions of chemistry and transport. Similar to past experiments reported in the literature, CO{sub 2}-diluted hydrogen in diluted or pure oxygen co-flowing streams in the proximity of the extinction limit are considered. As in the experiments, several preferred cellular states are found to co-exist with the particular state realized depending on initial conditions as well as on the jet characteristics. The simulations provide additionally the temporal transitions to different stationary or rotating cellular flames, their detailed structure, and the dependence of the scaling of the realized number of cells with the vorticity thickness. (author)

Valaer, A.L.; Frouzakis, C.E.; Boulouchos, K. [Aerothermochemistry and Combustion System Laboratory, Swiss Federal Institute of Technology, CH-8092 Zurich (Switzerland); Papas, P. [Division of Engineering, Colorado School of Mines, Golden, CO 80401 (United States); Tomboulides, A.G. [Department of Engineering and Management of Energy Resources, University of Western Macedonia, 50100 Kozani (Greece)

2010-04-15T23:59:59.000Z

335

Development of flame retarded self-reinforced composites from automotive shredder plastic waste  

Science Journals Connector (OSTI)

Multilayered self-reinforced composites were developed from a density-separated light fraction of automotive shredder waste of high polyolefin content, which can fulfil the current technical, safety and environmental requirements of structural materials. The significantly enhanced mechanical properties of the recycled composites were ensured by polypropylene fabric reinforcement; meanwhile, reduced flammability was obtained by modifying the matrix layers, made of secondary raw materials, with phosphorous-containing flame retardant additive. The results of the new flame retarded composite systems allowed the discussion of a novel mechanistic observation. The mechanical and flammability properties of the prepared self-reinforced composites are compared to conventional glass fabric reinforced composites and to compounds without reinforcement.

Katalin Bocz; Andrea Toldy; Ákos Kmetty; Tamás Bárány; Tamás Igricz; György Marosi

2012-01-01T23:59:59.000Z

336

Development of an energy efficient curtain flame ignition system for sintering of iron ore fines  

Science Journals Connector (OSTI)

Research and Development Centre for Iron and Steel (RDCIS) of Steel Authority of India Limited (SAIL) has developed a 'curtain flame' ignition system for sinter mix ignition. Conventionally, either horizontal fired burners or top fired or a combination of both are used for ignition of sinter mix. These burners big in size but few in number are mounted on a rectangular box type furnace. This is associated with non-uniform heating of sinter mix. In the new system, small capacity burners are installed on the roof across the sinter bed in a single row. Here, the top layer of the sinter bed gets heated by the direct impingement of the flame. This has resulted in reduction in specific fuel gas consumption by more than 30% and savings in refractory consumption. Implementation of the system led to reduction in green house gas (GHG) emission also.

V.T. Selvan; T.S. Reddy; A. Das

2012-01-01T23:59:59.000Z

337

Stabilized radio frequency quadrupole  

DOE Patents [OSTI]

Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1984-12-25T23:59:59.000Z

338

Heat transfer characteristics of laminar methane/air flame impinging normal to a cylindrical surface  

SciTech Connect (OSTI)

An experimental study has been conducted to determine the heat transfer characteristics of methane/air laminar flames impinging normal to a cylindrical surface. Effects of variations in the values of Reynolds number (Re = 600-1300), equivalence ratio ({phi} = 0.8-1.3), dimensionless separation distance (H/d = 1-5), and burner diameter to cylinder diameter ratio (d/D = 0.0538-0.1076) have been investigated. Three important configurations, viz., flame inner reaction zone far away, just touching and intercepted by the impingement surface, were examined in detail. High stagnation point heat fluxes were obtained when tip of the flame inner reaction zone just touched the target surface. Stagnation point heat fluxes were either zero or negative when the inner reaction zone was intercepted by the impingement surface. An off-stagnation peak in heat flux was obtained at moderate separation distances above the flame tip. Both stagnation point and peak heat fluxes increased with Re when the inner reaction zone length was less than the separation distance. Heat fluxes in the wall-jet region were high at high Re. Maximum heat fluxes were obtained for initially fuel-rich mixture conditions due to entrainment of the surrounding air. Smaller burner diameters produced high heat flux at the stagnation region for fixed Reynolds number and opposite trends were seen in the wall-jet region. A secondary rise in stagnation point heat flux was obtained at larger separation distances. This secondary rise in heat flux was quite significant for larger burner diameters and at low flow rates. Correlations were developed for stagnation point heat flux. Results were also compared with flat plate under identical operating conditions. (author)

Chander, Subhash; Ray, Anjan [Department of Mechanical Engineering, Indian Institute of Technology, Delhi, New Delhi 110 016 (India)

2007-11-15T23:59:59.000Z

339

Similarity solutions and applications to turbulent upward flame spread on noncharring materials  

SciTech Connect (OSTI)

The primary achievement in this work has been the discovery that turbulent upward flame spread on noncharring materials (for pyrolysis lengths less than 1.8m) can be directly predicted by using measurable flammability parameters. These parameters are: a characteristic length scale which is proportional to a turbulent combustion and mixing related length scale parameter ({dot q}{double_prime}{sub net}({Delta}H{sub c}/{Delta}H{sub v})){sup 2}, a pyrolysis or ignition time {tau}{sub p}, and a parameter which determines the transient pyrolysis history of a non-charring material: {lambda} = L/c{Delta}T{sub p} = ratio of the latent heat to the sensible heat of the pyrolysis temperature of the material. In the length scale parameter, {dot q}{double_prime}{sub net} is the total net heat flux from the flames to the wall (i.e., total heat flux minus reradiation losses), {Delta}H{sub c} is the heat of combustion and {Delta}H{sub v} is an effective heat of gasification for the material. The pyrolysis or ignition time depends (for thermally thick conditions) on the material thermal inertia, the pyrolysis temperature, and the total heat flux from the flames to the wall, {dot q}{double_prime}{sub fw}. The present discovery was made possible by using both a numerical simulation, developed earlier, and exact similarity solutions, which are developed in this work. The predictions of the analysis have been validated by comparison with upward flame spread experiments on PMMA.

Delichatsios, M.A.; Delichatsios, M.; Chen, Y. [Factory Mutual Research Corporation, Norwood, MA (United States)] [Factory Mutual Research Corporation, Norwood, MA (United States); Hasemi, Y. [Ministry of Construction, Tsukuba (Japan). Building Research Inst.] [Ministry of Construction, Tsukuba (Japan). Building Research Inst.

1995-08-01T23:59:59.000Z

340

Mechanism for Inhibition of Atmospheric-Pressure Syngas/Air Flames by Trimethylphosphate  

Science Journals Connector (OSTI)

Gasification processes allow for a wide range of solid combustibles, including coal, biomass, and municipal solid wastes, to be converted into syngas mixtures that can be burned in gas turbines to generate electricity. ... Burning velocity was measured using a Mache–Hebra nozzle burner(22) and the total area method(23) from flame images, as was performed by Linteris and Truett. ... Recommendations are made as to the most suitable methods of measuring burning velocity for both closed vessels and burners. ...

Vladimir M. Shvartsberg; Andrey G. Shmakov; Tatyana A. Bolshova; Oleg P. Korobeinichev

2012-08-10T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Low and High Temperature Combustion Chemistry of Butanol Isomers in Premixed Flames and Autoignition Systems  

SciTech Connect (OSTI)

Butanol is a fuel that has been proposed as a bio-derived alternative to conventional petroleum derived fuels. The structural isomer in traditional 'bio-butanol' fuel is n-butanol, but newer conversion technologies produce iso-butanol as a fuel. In order to better understand the combustion chemistry of bio-butanol, this study presents a comprehensive chemical kinetic model for all the four isomers of butanol (e.g., 1-, 2-, iso- and tert-butanol). The proposed model includes detailed high temperature and low temperature reaction pathways. In this study, the primary experimental validation target for the model is premixed flat low-pressure flame species profiles obtained using molecular beam mass spectrometry (MBMS). The model is also validated against previously published data for premixed flame velocity and n-butanol rapid compression machine and shock tube ignition delay. The agreement with these data sets is reasonably good. The dominant reaction pathways at the various pressures and temperatures studied are elucidated. At low temperature conditions, we found that the reaction of alphahydroxybutyl with O{sub 2} was important in controlling the reactivity of the system, and for correctly predicting C{sub 4} aldehyde profiles in low pressure premixed flames. Enol-keto isomerization reactions assisted by HO{sub 2} were also found to be important in converting enols to aldehydes and ketones in the low pressure premixed flames. In the paper, we describe how the structural features of the four different butanol isomers lead to differences in the combustion properties of each isomer.

Sarathy, S M; Pitz, W J; Westbrook, C K; Mehl, M; Yasunaga, K; Curran, H J; Tsujimura, T; Osswald, P; Kohse-Hoinghaus, K

2010-12-12T23:59:59.000Z

342

Virtual and super - virtual refraction method: Application to synthetic data and 2012 of Karangsambung survey data  

SciTech Connect (OSTI)

Seismic refraction survey is one of geophysical method useful for imaging earth interior, definitely for imaging near surface. One of the common problems in seismic refraction survey is weak amplitude due to attenuations at far offset. This phenomenon will make it difficult to pick first refraction arrival, hence make it challenging to produce the near surface image. Seismic interferometry is a new technique to manipulate seismic trace for obtaining Green's function from a pair of receiver. One of its uses is for improving first refraction arrival quality at far offset. This research shows that we could estimate physical properties such as seismic velocity and thickness from virtual refraction processing. Also, virtual refraction could enhance the far offset signal amplitude since there is stacking procedure involved in it. Our results show super - virtual refraction processing produces seismic image which has higher signal-to-noise ratio than its raw seismic image. In the end, the numbers of reliable first arrival picks are also increased.

Nugraha, Andri Dian [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Bandung, 40132 (Indonesia)] [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Bandung, 40132 (Indonesia); Adisatrio, Philipus Ronnie [Geophysical Engineering Department, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jl. Ganesha No. 10 Bandung, 40132 (Indonesia)] [Geophysical Engineering Department, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jl. Ganesha No. 10 Bandung, 40132 (Indonesia)

2013-09-09T23:59:59.000Z

343

Molecular Characterization of Organic Content of Soot along the Centerline of a Coflow Diffusion Flame  

SciTech Connect (OSTI)

High-resolution mass spectrometry coupled with nanospray desorption electrospray ionization was used to probe chemical constituents of young soot particles sampled along the centerline of a coflow diffusion flame of a three-component Jet-A1 surrogate. In lower positions where particles are transparent to light extinction (n= 632.8 nm), peri-condensed polycyclic aromatic hydrocarbons (PAHs) are found to be the major components of the particle material. These particles become enriched with aliphatic components as they grow in mass and size. Before carbonization occurs, the constituent species in young soot particles are aliphatic and aromatic compounds 200-600 amu in mass, some of which are oxygenated. Particles dominated by PAHs or mixtures of PAHs and aliphatics can both exhibit liquid-like appearance observed by electron microscopy and be transparent to visible light. The variations in chemical composition observed here indicate that the molecular processes of soot formation in coflow diffusion flames may be more complex than previously thought. For example, the mass growth and enrichment of aliphatic components in an initially, mostly aromatic structure region of the flame that is absent of H atoms or other free radicals indicates that there must exist at least another mechanism of soot mass growth in addition to the hydrogen-abstraction-carbon addition mechanism currently considered in fundamental models of soot formation.

Cain, Jeremy P.; Laskin, Alexander; Kholghy, Mohammad Reza; Thomson, Murray; Wang, Hai

2014-10-29T23:59:59.000Z

344

Flame Evolution During Type Ia Supernovae and the Deflagration Phase in the Gravitationally Confined Detonation Scenario  

E-Print Network [OSTI]

We develop an improved method for tracking the nuclear flame during the deflagration phase of a Type Ia supernova, and apply it to study the variation in outcomes expected from the gravitationally confined detonation (GCD) paradigm. A simplified 3-stage burning model and a non-static ash state are integrated with an artificially thickened advection-diffusion-reaction (ADR) flame front in order to provide an accurate but highly efficient representation of the energy release and electron capture in and after the unresolvable flame. We demonstrate that both our ADR and energy release methods do not generate significant acoustic noise, as has been a problem with previous ADR-based schemes. We proceed to model aspects of the deflagration, particularly the role of buoyancy of the hot ash, and find that our methods are reasonably well-behaved with respect to numerical resolution. We show that if a detonation occurs in material swept up by the material ejected by the first rising bubble but gravitationally confined to the white dwarf (WD) surface (the GCD paradigm), the density structure of the WD at detonation is systematically correlated with the distance of the deflagration ignition point from the center of the star. Coupled to a suitably stochastic ignition process, this correlation may provide a plausible explanation for the variety of nickel masses seen in Type Ia Supernovae.

D. M. Townsley; A. C. Calder; S. M. Asida; I. R. Seitenzahl; F. Peng; N. Vladimirova; D. Q. Lamb; J. W. Truran

2007-06-07T23:59:59.000Z

345

Nanoengineering core/shell structured brucite@polyphosphate@amine hybrid system for enhanced flame retardant properties  

Science Journals Connector (OSTI)

Abstract A novel organic-inorganic hybrid flame retardant consisting of a brucite core and a dodecylamine polyphosphate shell was synthesized by a facile nanoengineering route. The flammability characterization and synergistic flame retardant mechanism of the core/shell flame retardant (CFR) in ethylene-vinyl acetate (EVA) blends had been compared with EVA/physical mixture (PM, with the given proportion of brucite and dodecylamine polyphosphate as well as CFR) and EVA/brucite blends. With the same loading amount (40 wt%) of fillers in EVA, the peak heat release rate and smoke production rate of EVA/CFR blends were significantly reduced to 49% and 48% of that of EVA/PM blends, respectively. Meanwhile, the limiting oxygen index (LOI) was increased up to 32 (14.3% higher than that of EVA/PM blends) and the UL-94 test could achieve the V-0 rating. These remarkable properties were obtained just by nanoengineeing the core/shell structured brucite@polyphosphate@amine hybrid system, facilitating the formation of intact and compact residue with fence structure in process of polymer composite burning.

Xuesong Wang; Hongchang Pang; Wendan Chen; Yuan Lin; Guiling Ning

2013-01-01T23:59:59.000Z

346

Flame propagation and counterflow nonpremixed ignition of mixtures of methane and ethylene  

SciTech Connect (OSTI)

The ignition temperature of nitrogen-diluted mixtures of methane and ethylene counterflowing against heated air was measured up to five atmospheres. In addition, the stretch-corrected laminar flame speeds of mixtures of air, methane and ethylene were determined from outwardly-propagating spherical flames up to 10 atmospheres, for extensive range of the lean-to-rich equivalence ratio. These experimental data, relevant to low- to moderately-high-temperature ignition chemistry and high-temperature flame chemistry, respectively, were subsequently compared with calculations using two detailed kinetic mechanisms. A chemical explosive mode analysis (CEMA) was then conducted to identify the dominant ignition chemistry and the role of ethylene addition in facilitating nonpremixed ignition. Furthermore, the hierarchical structure of the associated oxidation kinetics was examined by comparing the sizes and constituents of the skeletal mechanisms of the pure fuels and their mixtures, derived using the method of directed relation graph (DRG). The skeletal mechanism was further reduced by time-scale analysis, leading to a 24-species reduced mechanism from the detailed mechanism of USC Mech II, validated within the parameter space of the conducted experiments. (author)

Liu, W.; Kelley, A.P.; Law, C.K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

2010-05-15T23:59:59.000Z

347

Evidence of thermonuclear flame spreading on neutron stars from burst rise oscillations  

E-Print Network [OSTI]

Burst oscillations during the rising phases of thermonuclear X-ray bursts are usually believed to originate from flame spreading on the neutron star surface. However, the decrease of fractional oscillation amplitude with rise time, which provides a main observational support for the flame spreading model, have so far been reported from only a few bursts. Moreover, the non-detection and intermittent detections of rise oscillations from many bursts are not yet understood considering the flame spreading scenario. Here, we report the decreasing trend of fractional oscillation amplitude from an extensive analysis of a large sample of Rossi X-ray Timing Explorer Proportional Counter Array bursts from ten neutron star low-mass X-ray binaries. This trend is 99.99% significant for the best case, which provides, to the best of our knowledge, by far the strongest evidence of such trend. Moreover, it is important to note that an opposite trend is not found from any of the bursts. The concave shape of the fractional ampli...

Chakraborty, Manoneeta

2014-01-01T23:59:59.000Z

348

Rotational effects in thermonuclear Type I Bursts: equatorial crossing and directionality of flame spreading  

E-Print Network [OSTI]

In a previous study on thermonuclear (Type I) Bursts on accreting neutron stars we addressed and demonstrated the importance of the effects of rotation, through the Coriolis force, on the propagation of the burning flame. However, that study only analysed cases of longitudinal propagation, where the Coriolis force coefficient $2\\Omega\\cos\\theta$ was constant. In this paper, we study the effects of rotation on propagation in the meridional (latitudinal) direction, where the Coriolis force changes from its maximum at the poles to zero at the equator. We find that the zero Coriolis force at the equator, while affecting the structure of the flame, does not prevent its propagation from one hemisphere to another. We also observe structural differences between the flame propagating towards the equator and that propagating towards the pole, the second being faster. In the light of the recent discovery of the low spin frequency of burster IGR~J17480-2446 rotating at 11 Hz (for which Coriolis effects should be negligib...

Cavecchi, Yuri; Levin, Yuri; Braithwaite, Jonathan

2014-01-01T23:59:59.000Z

349

T-678: Red Hat Enterprise Virtualization Hypervisor VLAN Packet Processing  

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

8: Red Hat Enterprise Virtualization Hypervisor VLAN Packet 8: Red Hat Enterprise Virtualization Hypervisor VLAN Packet Processing Flaw Lets Remote Users Deny Service T-678: Red Hat Enterprise Virtualization Hypervisor VLAN Packet Processing Flaw Lets Remote Users Deny Service July 28, 2011 - 3:47pm Addthis PROBLEM: A vulnerability was reported in Red Hat Enterprise Virtualization Hypervisor. A remote user can cause denial of service conditions. PLATFORM: Red Hat Enterprise Virtualization-hypervisor package. ABSTRACT: Red Hat Enterprise Virtualization Hypervisor VLAN Packet Processing Flaw Lets Remote Users Deny Service. reference LINKS: RHSA-2011:1090-1 SecurityTracker Alert ID: 1025853 CVE-2011-1576 RHBA-2011:1068-1,Hypervisor is based on KVM - Bug Fix Advisory IMPACT ASSESSMENT: Medium Discussion: A flaw was found that allowed napi_reuse_skb() to be called on VLAN

350

Best Practices for Engaging Virtual Training | Department of Energy  

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

You are here You are here Home » Best Practices for Engaging Virtual Training Best Practices for Engaging Virtual Training Course Title: CCBP-Best Practices for Engaging Virtual Training Date: Online course Time: At your discretion Registration link: Best Practices for Engaging Virtual Training / http://www.trainingindustry.com/webinars/best-practices-for-engaging-virtual-training.aspx Course type: Recorded Webinar Course Location: N/A Course Description: Ensuring that virtual training is engaging and grabs the attention of the audience is crucial to the success of the program. Join us for this TrainingIndustry.com webinar, presented on the Adobe Connect platform, to hear Jacqueline Beck, a Master Trainer for Adobe, share her expertise and tips on best practices for engaging learners in the

351

Al/Al2O3 Composite Coating Deposited by Flame Spraying for Marine Applications: Alumina Skeleton Enhances Anti-Corrosion and Wear Performances  

Science Journals Connector (OSTI)

Here we report aluminum-alumina composite coatings fabricated by flame spraying for potential marine applications against both corrosion and wear. Microstructure examination suggested dense coating structures and...

Jing Huang; Yi Liu; Jianhui Yuan; Hua Li

2014-04-01T23:59:59.000Z

352

Interference mechanisms of acoustic/convective disturbances in a swirl-stabilized lean-premixed combustor  

Science Journals Connector (OSTI)

Interference mechanisms of acoustic/convective disturbances were experimentally investigated in a swirl-stabilized lean-premixed gas turbine combustor operated with natural gas fuel and air at atmospheric pressure and elevated temperature. Interference between azimuthal and acoustic velocity disturbances at high-amplitude limit cycle oscillations is characterized in detail as a function of axial swirler location, oscillation frequency, and mean nozzle velocity. We show that both the frequency and the intensity of self-excited instabilities in a model gas turbine combustor are correlated with axial swirler position, which indicates that a vorticity wave generated at the swirl vanes is a primary source of convective disturbances in the absence of equivalence ratio nonuniformities. Flame transfer function measurements confirm that the linear/nonlinear heat release response is a strong function of axial swirler location, even when unforced flame structures remain unchanged. The key parameter controlling this phenomenon is the phase difference between the azimuthal and acoustic velocity perturbations at the combustor dump plane; the phase difference is affected by swirler location, frequency, mean velocity, and the speed of sound. It was found that out-of-phase interference between azimuthal and acoustic velocity disturbances at the combustor inlet yields large flame angle fluctuations in relation to swirl number fluctuations, and therefore the formation of a coherent structure is hindered due to high kinematic viscosity within the vortex formation region. In-phase interference mechanisms, on the other hand, lead to high-amplitude limit cycle oscillations. This interference mechanism is then explored in the presence of temporal equivalence ratio nonuniformities, in which two different sources of convective mechanisms should be considered simultaneously in connection with acoustic velocity perturbations and the vortex dynamics. Results reveal that equivalence ratio oscillation has a significant effect on the strength of combustion-acoustic interactions. Strong self-excited instabilities of partially premixed flames are produced by in-phase interactions between acoustic velocity and equivalence ratio oscillations, which are governed by fuel injection location, frequency, mean nozzle velocity, and fuel injector impedance. At this phase condition, unburned reactants with high equivalence ratio impinge on the flame front with high inlet velocity, potentially causing large fluctuations of heat release rate.

Kyu Tae Kim; Dom A. Santavicca

2013-01-01T23:59:59.000Z

353

Virtual Power Plant Simulation and Control Scheme Design.  

E-Print Network [OSTI]

?? Virtual Power Plant (VPP) is a concept that aggregate Distributed Energy Resources (DER) together, aims to overcome the capacity limits of single DER and… (more)

Chen, Zhenwei

2012-01-01T23:59:59.000Z

354

Virtual building environments (VBE) - Applying information modeling tobuildings  

E-Print Network [OSTI]

and valuation of Virtual Building Modeling (VBM). CIFE SEEDinformation models Building information modeling (BIM), usedto promote building information modeling as the way to

Bazjanac, Vladimir

2004-01-01T23:59:59.000Z

355

I/O Performance of Virtualized Cloud Environments  

E-Print Network [OSTI]

Technologies in High Performance Computing. In 2nd IEEEon UnConventional high performance computing workshop plususing virtual high-performance computing: a case study using

Ghoshal, Devarshi

2013-01-01T23:59:59.000Z

356

Virtual Aluminum Castings An Industrial Application of Integrated...  

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

Virtual Aluminum Castings An Industrial Application of Integrated Computational Materials Engineering Home Author: J. Allison, M. Li, C. Wolverton, X. Su Year: 2006 Abstract: The...

357

Proposed Virtual Center for Excellence for Metal Hydride Development...  

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

Virtual Center for Excellence for Metal Hydride Development Presentation from the Hydrogen Storage Pre-Solicitation Meeting held June 19, 2003 in Washington, DC....

358

Virtual Center of Excellence for Hydrogen Storage - Chemical...  

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

Engineering and Environmental Laboratory Virtual Center of Excellence for Hydrogen Storage - Chemical Hydrides Pre-Solicitation Presentation James Lake, PhD Associate Laboratory...

359

Virtual Worlds: A Performative Perspective on Globally Distributed, Immersive Work  

E-Print Network [OSTI]

Virtual worlds are immersive, simulated, persistent, and dynamic environments that include rich graphical three dimensional spaces, high fidelity audio, motion, viewpoint, and interactivity. Initially dismissed as environments ...

Schultze, Ulrike

360

Perception-Action Loop in the Experience of Virtual Environments  

E-Print Network [OSTI]

the screen, the (white) teapot moves to the right at highclosest object, the (white) teapot is farthest one, and thecylinder, cone, box and teapot) hidden behind virtual walls,

Kim, Seung Wook

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Virtual Oxygen Sensor for Innovative NOx and PM Emission Control...  

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

2009 - Poster Session August 3 rd , Hyatt Regency Dearborn Hotel Virtual Oxygen Sensor Innovative NOx and PM Emission Control Technologies J. Seebode, E. Stlting,...

362

A Stochastic Reactor Based Virtual Engine Model Employing Detailed...  

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

A Stochastic Reactor Based Virtual Engine Model Employing Detailed Chemistry for Kinetic Studies of In-Cylinder Combustion and Exhaust Aftertreatment A Stochastic Reactor Based...

363

Implementing virtual reality interfaces for the geosciences  

SciTech Connect (OSTI)

For the past few years, a multidisciplinary team of computer and earth scientists at Lawrence Berkeley National Laboratory has been exploring the use of advanced user interfaces, commonly called {open_quotes}Virtual Reality{close_quotes} (VR), coupled with visualization and scientific computing software. Working closely with industry, these efforts have resulted in an environment in which VR technology is coupled with existing visualization and computational tools. VR technology may be thought of as a user interface. It is useful to think of a spectrum, ranging the gamut from command-line interfaces to completely immersive environments. In the former, one uses the keyboard to enter three or six-dimensional parameters. In the latter, three or six-dimensional information is provided by trackers contained either in hand-held devices or attached to the user in some fashion, e.g. attached to a head-mounted display. Rich, extensible and often complex languages are a vehicle whereby the user controls parameters to manipulate object position and location in a virtual world, but the keyboard is the obstacle in that typing is cumbersome, error-prone and typically slow. In the latter, the user can interact with these parameters by means of motor skills which are highly developed. Two specific geoscience application areas will be highlighted. In the first, we have used VR technology to manipulate three-dimensional input parameters, such as the spatial location of injection or production wells in a reservoir simulator. In the second, we demonstrate how VR technology has been used to manipulate visualization tools, such as a tool for computing streamlines via manipulation of a {open_quotes}rake.{close_quotes} The rake is presented to the user in the form of a {open_quotes}virtual well{close_quotes} icon, and provides parameters used by the streamlines algorithm.

Bethel, W.; Jacobsen, J. [Lawrence Berkeley National Laboratory, CA (United States); Austin, A.; Lederer, M. [BP Exploration, Houston, TX (United States); Little, T. [Landmark Graphics Corp., Houston, TX (United States)

1996-06-01T23:59:59.000Z

364

Validating agent based models through virtual worlds.  

SciTech Connect (OSTI)

As the US continues its vigilance against distributed, embedded threats, understanding the political and social structure of these groups becomes paramount for predicting and dis- rupting their attacks. Agent-based models (ABMs) serve as a powerful tool to study these groups. While the popularity of social network tools (e.g., Facebook, Twitter) has provided extensive communication data, there is a lack of ne-grained behavioral data with which to inform and validate existing ABMs. Virtual worlds, in particular massively multiplayer online games (MMOG), where large numbers of people interact within a complex environ- ment for long periods of time provide an alternative source of data. These environments provide a rich social environment where players engage in a variety of activities observed between real-world groups: collaborating and/or competing with other groups, conducting battles for scarce resources, and trading in a market economy. Strategies employed by player groups surprisingly re ect those seen in present-day con icts, where players use diplomacy or espionage as their means for accomplishing their goals. In this project, we propose to address the need for ne-grained behavioral data by acquiring and analyzing game data a commercial MMOG, referred to within this report as Game X. The goals of this research were: (1) devising toolsets for analyzing virtual world data to better inform the rules that govern a social ABM and (2) exploring how virtual worlds could serve as a source of data to validate ABMs established for analogous real-world phenomena. During this research, we studied certain patterns of group behavior to compliment social modeling e orts where a signi cant lack of detailed examples of observed phenomena exists. This report outlines our work examining group behaviors that underly what we have termed the Expression-To-Action (E2A) problem: determining the changes in social contact that lead individuals/groups to engage in a particular behavior. Results from our work indicate that virtual worlds have the potential for serving as a proxy in allocating and populating behaviors that would be used within further agent-based modeling studies.

Lakkaraju, Kiran; Whetzel, Jonathan H.; Lee, Jina [Sandia National Laboratories, Livermore, CA] [Sandia National Laboratories, Livermore, CA; Bier, Asmeret Brooke; Cardona-Rivera, Rogelio E. [North Carolina State University, Raleigh, NC] [North Carolina State University, Raleigh, NC; Bernstein, Jeremy Ray Rhythm [Gaikai, Inc., Aliso Viejo, CA] [Gaikai, Inc., Aliso Viejo, CA

2014-01-01T23:59:59.000Z

365

Deeply Virtual Compton Scattering off the neutron  

E-Print Network [OSTI]

The present experiment exploits the interference between the Deeply Virtual Compton Scattering (DVCS) and the Bethe-Heitler processes to extract the imaginary part of DVCS amplitudes on the neutron and on the deuteron from the helicity-dependent D$({\\vec e},e'\\gamma)X$ cross section measured at $Q^2$=1.9 GeV$^2$ and $x_B$=0.36. We extract a linear combination of generalized parton distributions (GPDs) particularly sensitive to $E_q$, the least constrained GPD. A model dependent constraint on the contribution of the up and down quarks to the nucleon spin is deduced.

M. Mazouz; A. Camsonne; C. Muñoz Camacho; for the Jefferson Lab Hall A collaboration

2007-09-04T23:59:59.000Z

366

Electromagnetic wormholes and virtual magnetic monopoles  

E-Print Network [OSTI]

We describe new configurations of electromagnetic (EM) material parameters, the electric permittivity $\\epsilon$ and magnetic permeability $\\mu$, that allow one to construct from metamaterials objects that function as invisible tunnels. These allow EM wave propagation between two points, but the tunnels and the regions they enclose are not detectable to EM observations. Such devices function as wormholes with respect to Maxwell's equations and effectively change the topology of space vis-a-vis EM wave propagation. We suggest several applications, including devices behaving as virtual magnetic monopoles.

Allan Greenleaf; Yaroslav Kurylev; Matti Lassas; Gunther Uhlmann

2007-03-20T23:59:59.000Z

367

Virtual doctor's office telemedicine delivery system  

E-Print Network [OSTI]

Approved a s and nte t by: Charles S. L a Chair of Committee) Hsin-I Wu (Member) Jon F. Hunter (Member) William J. Hy n (Head of Department) December 2002 Major Subject: Biomedical Engineering ABSTRACT Virtual Doctor's Office Telemedicine... the course of my education at Texas AItM University. He has been a source of constant encouragement and guidance during my stay at the university. I would also like to acknowledge the help extended by Dr. don F. Hunter in obtaining the test data...

Sainath, Paavana

2012-06-07T23:59:59.000Z

368

Energy efficient mapping of virtualEnergy efficient mapping of virtual machinesmachines  

E-Print Network [OSTI]

for energy savings in cloud 2 Violaine Villebonnet GreenDays@Lille 28th November 2013 Problematic algorithms that best fit with reality Energy efficient mapping of virtual machines Violaine Villebonnet Green Conditioning Reduce the energy consumption of the whole datacenter Violaine Villebonnet GreenDays@Lille 28th

Lefèvre, Laurent

369

Experimental spheromak MHD stability studies  

Science Journals Connector (OSTI)

The n = 1 tilt and radial shift instability of spheromaks is shown to be stabilized by the use of conducting wall (rwrs?1.2) and stabilization coils.

G.C. Goldenbaum; H. Bruhns; C. Chin-Fatt; Y.P. Chong; A.W. DeSilva; H.R. Griem; G.W. Hart; R.A. Hess; J.H. Irby; R.S. Shaw; Z.Y. Zhu

1983-01-01T23:59:59.000Z

370

Ideal Stabilization Mikhail Nesterenko  

E-Print Network [OSTI]

StabilizationLegitimate #12;Questions · Existence ? · Construction ? · Composition ? · Implementation vs Mappings Program #12;Leader Election L L L L L L L L #12;Leader Election L L #12;Leader Election L L #12

Nesterenko, Mikhail

371

Virtual Divestitures, Will They Make A Difference?: Cournot Competition, Options Markets and Efficiency  

E-Print Network [OSTI]

of such a divestiture of Virtual Power Plants (VPPs), andand physical Virtual Power Plants. The second goal (sectionFabra (2004). Virtual Power Plants In this new philosophy of

Willems, Bert

2006-01-01T23:59:59.000Z

372

Virtual Reviewers for Collaborative Exploration of Movie Reviews  

E-Print Network [OSTI]

items well. Collaborative information exploration virtualizes this process by using rating data. We haveVirtual Reviewers for Collaborative Exploration of Movie Reviews Junichi Tatemura Institute tatemura@iis.u-tokyo.ac.jp ABSTRACT We propose a collaborative exploration system that helps users

373

Exploring Humanoid Robots Locomotion Capabilities in Virtual Disaster Response Scenarios  

E-Print Network [OSTI]

since the Fukushima Daiichi nuclear power plant accident that followed the 2011 Great East JapanExploring Humanoid Robots Locomotion Capabilities in Virtual Disaster Response Scenarios Karim-like motor skills to be achieved. We use virtual scenes under the fully- 3D-modeled-environment assumption

Paris-Sud XI, Université de

374

The role of socialization in Knowledge management in virtual teams  

Science Journals Connector (OSTI)

The literature shows that new Knowledge creation methods underline the importance of team networks as a pillar of Knowledge creation in modern Organizations. Sharing tacit Knowledge is one of the difficulties of virtual teams (VTs). This is due to knowledge ... Keywords: cultural facilitator factors, knowledge management, learning socialization content, socialization tactics, virtual teams

Artemis Akhgar; Aryan Gholipour

2011-07-01T23:59:59.000Z

375

Collaborative learning in multi-user virtual environments  

Science Journals Connector (OSTI)

Multi-user virtual environments (MUVEs) have captured the attention and interest of educators as remote collaborative learning environments due to their immersion, interaction and communication capabilities. However, productive learning interactions ... Keywords: 3D virtual worlds, Collaborative learning techniques and platforms, Collaborative workflows and applications, Collaborative workspaces and applications

María Blanca Ibáñez; José J. García Rueda; David Maroto; Carlos Delgado Kloos

2013-11-01T23:59:59.000Z

376

SMART CAMERA NETWORKS IN VIRTUAL REALITY Faisal Qureshi  

E-Print Network [OSTI]

(right). (The yel- low rectangles indicate pedestrian portals.) An example camera net- work-animating virtual pedestrians (Fig. 1). Figure 1: Plan view of the (roofless) virtual Penn Station envi- ronment simulated video surveillance cameras 1, 7, and 8 (from [1]). Once a pedestrian of interest is selected

Qureshi, Faisal Z.

377

Virtual Vision and Smart Camera Networks Faisal Qureshi  

E-Print Network [OSTI]

shopping arcade (right). (The yellow rectangles indicate station pedestrian portals.) An example camera-animating virtual pedestrians. The readily re- configurable virtual cameras generate synthetic video feeds to collaborate in performing various visual surveillance tasks, such as closely monitoring a pedestrian as (s

Toronto, University of

378

Towards an Algebraic Speci cation of the Java Virtual Machine  

E-Print Network [OSTI]

Towards an Algebraic Speci cation of the Java Virtual Machine K Stephenson Department of Computer of the architecture of an abstract and simpli ed version of the Java Virtual Machine JVM. This concentration on the implementation-independent features of the machine allows us to build a clean and easily comprehensible model

Grant, P. W.

379

this version: May 13, 2011 A semantic virtual machine  

E-Print Network [OSTI]

this version: May 13, 2011 A semantic virtual machine Arnold Neumaier Peter Schodl Fakult¨at f://www.mat.univie.ac.at/neum/FMathL Abstract A semantic virtual machine (SVM) is a variant of a programable register machine that combines the transparency and simplicity of the action of a Turing machine with a clearly arranged assembler

Neumaier, Arnold

380

Towards an Algebraic Specification of the Java Virtual Machine  

E-Print Network [OSTI]

Towards an Algebraic Specification of the Java Virtual Machine K Stephenson Department of Computer of the architecture of an abstract and simplified version of the Java Virtual Machine (JVM). This concentration on the implementation­independent features of the machine allows us to build a clean and easily comprehensible model

Grant, P. W.

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Supporting Decentralized, Security focused Dynamic Virtual Organizations across the Grid  

E-Print Network [OSTI]

Supporting Decentralized, Security focused Dynamic Virtual Organizations across the Grid R and subsequently manage secure virtual organisations (VO) is one of the key challenges facing the Grid community in the education domain. We believe that this federated VO security model for fine grained access to Grid services

Kent, University of

382

A modeling framework for agile and interoperable virtual enterprises  

Science Journals Connector (OSTI)

The virtual enterprise (VE), in general collaborations among business partners in value chains, has become a prime candidate model for competitiveness under the increasingly turbulent business environment. In order to quickly respond to the rapidly changing ... Keywords: Enterprise architecture, Enterprise engineering, Meta-modeling, Modeling framework, Virtual enterprise

Tae-Young Kim; Sunjae Lee; Kwangsoo Kim; Cheol-Han Kim

2006-04-01T23:59:59.000Z

383

Virtual Engineering in Industry www.iit.tu-Berlin.de  

E-Print Network [OSTI]

Virtual Engineering in Industry E-Bike www.iit.tu-Berlin.de in coorporation with Audi E-Bike Please.: +49 (0) 30 / 3 90 06-111 Realistic product development The lecture course Virtual Engineering high motivation, creativity, ability to work in a team working in small groups with different roles

Berlin,Technische Universität

384

LEGITIMATE BY DESIGN: TOWARDS TRUSTED VIRTUAL COMMUNITY ENVIRONMENTS  

E-Print Network [OSTI]

over the next decade. Virtual community. A virtual community (VC) is a self-sustaining group, with persisting social practices, acting in a common computer-mediated space. Groups are self-sustaining when and go. A community is also a form of self-sustaining group interaction that endures. The formation

Whitworth, Brian

385

Surface Light Field Rendering for Virtual Product Design  

E-Print Network [OSTI]

of existing or virtual objects left: photograph, right: SLF Wood et al. 2000 real and virtual objects Chen et ­ Fixed geometry ( ) ( ) ( ) ( )( ) i iSLF x,v x,l,v L x,l n x l dl = material incoming light orientation #12;Test Setup Leather BTF yellowish area light source mirror car seat #12;SLF Computation · About

Behnke, Sven

386

P2P grid technology for virtual classrooms and laboratories  

Science Journals Connector (OSTI)

Computing technologies can play important role in Virtual Classrooms and Laboratories (VCL) and e-learning settings. In these systems, the underlying computing platforms enable large number of students across the globe to collaborate and interact with ... Keywords: P2P grid, cloud computing, distributed network computing, grid computing, virtual classrooms

Hassan Rajaei; Nada Hakami

2013-04-01T23:59:59.000Z

387

Small Group Collaboration and Presence in a Virtual Environment  

E-Print Network [OSTI]

Small Group Collaboration and Presence in a Virtual Environment J Casanueva E Blake Collaborative, South Africa. jcasanue,edwin @cs.uct.ac.za Abstract Presence in Collaborative Virtual Environments (CVEs as the other participants, and that one is collaborating with real people. In this paper we describe

Blake, Edwin

388

Stabilization of compactible waste  

SciTech Connect (OSTI)

This report summarizes the results of series of experiments performed to determine the feasibility of stabilizing compacted or compactible waste with polymers. The need for this work arose from problems encountered at disposal sites attributed to the instability of this waste in disposal. These studies are part of an experimental program conducted at Brookhaven National Laboratory (BNL) investigating methods for the improved solidification/stabilization of DOE low-level wastes. The approach taken in this study was to perform a series of survey type experiments using various polymerization systems to find the most economical and practical method for further in-depth studies. Compactible dry bulk waste was stabilized with two different monomer systems: styrene-trimethylolpropane trimethacrylate (TMPTMA) and polyester-styrene, in laboratory-scale experiments. Stabilization was accomplished by wetting or soaking compactible waste (before or after compaction) with monomers, which were subsequently polymerized. Three stabilization methods are described. One involves the in-situ treatment of compacted waste with monomers in which a vacuum technique is used to introduce the binder into the waste. The second method involves the alternate placement and compaction of waste and binder into a disposal container. In the third method, the waste is treated before compaction by wetting the waste with the binder using a spraying technique. A series of samples stabilized at various binder-to-waste ratios were evaluated through water immersion and compression testing. Full-scale studies were conducted by stabilizing two 55-gallon drums of real compacted waste. The results of this preliminary study indicate that the integrity of compacted waste forms can be readily improved to ensure their long-term durability in disposal environments. 9 refs., 10 figs., 2 tabs.

Franz, E.M.; Heiser, J.H. III; Colombo, P.

1990-09-01T23:59:59.000Z

389

Nonlinearity 10 (1997) 12. Printed in the UK PII: S0951-7715(97)79608-7 Cover illustration: Non-premixed hydrocarbon flame  

E-Print Network [OSTI]

by the density difference from the combustion heat release and resulting temperature rise. The Reynolds number Publishing Ltd and LMS Publishing Ltd 1 #12;2 P E Dimotakis Combustion in non-premixed hydrocarbon flames-premixed hydrocarbon flame Paul E Dimotakis Graduate Aeronautical Laboratories, California Institute of Technology

Dimotakis, Paul E.

390

Methods and systems relating to an augmented virtuality environment  

DOE Patents [OSTI]

Systems and methods relating to an augmented virtuality system are disclosed. A method of operating an augmented virtuality system may comprise displaying imagery of a real-world environment in an operating picture. The method may further include displaying a plurality of virtual icons in the operating picture representing at least some assets of a plurality of assets positioned in the real-world environment. Additionally, the method may include displaying at least one virtual item in the operating picture representing data sensed by one or more of the assets of the plurality of assets and remotely controlling at least one asset of the plurality of assets by interacting with a virtual icon associated with the at least one asset.

Nielsen, Curtis W; Anderson, Matthew O; McKay, Mark D; Wadsworth, Derek C; Boyce, Jodie R; Hruska, Ryan C; Koudelka, John A; Whetten, Jonathan; Bruemmer, David J

2014-05-20T23:59:59.000Z

391

An object-oriented extension for debugging the virtual machine  

SciTech Connect (OSTI)

A computer is nothing more then a virtual machine programmed by source code to perform a task. The program`s source code expresses abstract constructs which are compiled into some lower level target language. When a virtual machine breaks, it can be very difficult to debug because typical debuggers provide only low-level target implementation information to the software engineer. We believe that the debugging task can be simplified by introducing aspects of the abstract design and data into the source code. We introduce OODIE, an object-oriented extension to programming languages that allows programmers to specify a virtual environment by describing the meaning of the design and data of a virtual machine. This specification is translated into symbolic information such that an augmented debugger can present engineers with a programmable debugging environment specifically tailored for the virtual machine that is to be debugged.

Pizzi, R.G. Jr. [California Univ., Davis, CA (United States)

1994-12-01T23:59:59.000Z

392

Linear eddy mixing based tabulation and artificial neural networks for large eddy simulations of turbulent flames  

SciTech Connect (OSTI)

A large eddy simulation (LES) sub-grid model is developed based on the artificial neural network (ANN) approach to calculate the species instantaneous reaction rates for multi-step, multi-species chemical kinetics mechanisms. The proposed methodology depends on training the ANNs off-line on a thermo-chemical database representative of the actual composition and turbulence (but not the actual geometrical problem) of interest, and later using them to replace the stiff ODE solver (direct integration (DI)) to calculate the reaction rates in the sub-grid. The thermo-chemical database is tabulated with respect to the thermodynamic state vector without any reduction in the number of state variables. The thermo-chemistry is evolved by stand-alone linear eddy mixing (LEM) model simulations under both premixed and non-premixed conditions, where the unsteady interaction of turbulence with chemical kinetics is included as a part of the training database. The proposed methodology is tested in LES and in stand-alone LEM studies of three distinct test cases with different reduced mechanisms and conditions. LES of premixed flame-turbulence-vortex interaction provides direct comparison of the proposed ANN method against DI and ANNs trained on thermo-chemical database created using another type of tabulation method. It is shown that the ANN trained on the LEM database can capture the correct flame physics with accuracy comparable to DI, which cannot be achieved by ANN trained on a laminar premix flame database. A priori evaluation of the ANN generality within and outside its training domain is carried out using stand-alone LEM simulations as well. Results in general are satisfactory, and it is shown that the ANN provides considerable amount of memory saving and speed-up with reasonable and reliable accuracy. The speed-up is strongly affected by the stiffness of the reduced mechanism used for the computations, whereas the memory saving is considerable regardless. (author)

Sen, Baris Ali; Menon, Suresh [School of Aerospace Engineering, Georgia Institute of Technology, 270 Ferst Drive, Atlanta, GA 30332-0150 (United States)

2010-01-15T23:59:59.000Z

393

On molecular transport effects in real gas laminar diffusion flames at large pressure  

Science Journals Connector (OSTI)

Direct numerical simulations are conducted of unsteady exothermic and one-dimensional laminar diffusionflames at large pressures. The simulations are used to assess the impact of molecular diffusion and real gas effects under high pressure conditions with simplified chemical kinetics. The formulation includes the fully compressible form of the governing equations real gas effects modeled by the cubic Peng–Robinson equation of state and a generalized form of the Soret and Dufour mass and heat diffusion vectors derived from nonequilibrium thermodynamics and fluctuation theory. The cross diffusion fluxes are derived for a ternary species system and include the effects of both heat and mass diffusion in the presence of temperature concentration and pressure gradients (i.e. Soret and Dufour diffusion). The ternary species formulation is applied to a simplified single step reaction elucidating molecular and thermodynamic effects apparent in general combustion. Realistic models for pressure temperature and species dependent heat capacities viscosities thermal conductivities and mass diffusivities are also included. Three different model reactions are simulated both including and neglecting Soret and Dufour cross diffusion. The simulation results show that Soret and Dufour effects are negligible for reactions comprised of species with equal or near equal molecular weights. However Soret diffusion effects are apparent when species with nonequal molecular weights are involved in the reaction and result in reductions of the peak flame temperature. In addition it is shown that neglect of cross diffusion leads to deviations in the predicted flame thicknesses with under predictions for a hydrogen-oxygen system and over predictions for a heavy hydrocarbon reaction. These effects are explained in detail through examinations of the individual heat and mass flux vectors as well as through associated thermodynamic properties. A parametric study addresses the effects of the ambient pressure the initial “flame Reynolds number ” the Damkohler number and the heat release parameter.

Sridhar Palle; Christopher Nolan; Richard S. Miller

2005-01-01T23:59:59.000Z

394

Scaling and efficiency of PRISM in adaptive simulations of turbulent premixed flames  

SciTech Connect (OSTI)

The dominant computational cost in modeling turbulent combustion phenomena numerically with high fidelity chemical mechanisms is the time required to solve the ordinary differential equations associated with chemical kinetics. One approach to reducing that computational cost is to develop an inexpensive surrogate model that accurately represents evolution of chemical kinetics. One such approach, PRISM, develops a polynomial representation of the chemistry evolution in a local region of chemical composition space. This representation is then stored for later use. As the computation proceeds, the chemistry evolution for other points within the same region are computed by evaluating these polynomials instead of calling an ordinary differential equation solver. If initial data for advancing the chemistry is encountered that is not in any region for which a polynomial is defined, the methodology dynamically samples that region and constructs a new representation for that region. The utility of this approach is determined by the size of the regions over which the representation provides a good approximation to the kinetics and the number of these regions that are necessary to model the subset of composition space that is active during a simulation. In this paper, we assess the PRISM methodology in the context of a turbulent premixed flame in two dimensions. We consider a range of turbulent intensities ranging from weak turbulence that has little effect on the flame to strong turbulence that tears pockets of burning fluid from the main flame. For each case, we explore a range of sizes for the local regions and determine the scaling behavior as a function of region size and turbulent intensity.

Tonse, Shaheen R.; Bell, J.B.; Brown, N.J.; Day, M.S.; Frenklach, M.; Grcar, J.F.; Propp, R.M.

1999-12-01T23:59:59.000Z

395

E-Print Network 3.0 - augmented virtual experiences Sample Search...  

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

for: augmented virtual experiences Page: << < 1 2 3 4 5 > >> 1 Outdoor Virtual Reality Bruce H. Thomas and Wayne Piekarski Summary: This paper presents our novel concept Outdoor...

396

LANL/PNNL Virtual Center for Chemical Hydrides and New Concepts...  

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

LANLPNNL Virtual Center for Chemical Hydrides and New Concepts for Hydrogen Storage LANLPNNL Virtual Center for Chemical Hydrides and New Concepts for Hydrogen Storage...

397

Demonstration of triple pump coherent anti-Stokes Raman scattering in a jet diffusion flame  

E-Print Network [OSTI]

. A. Theory 1. Coherent anti-Stokes Raman scattering basics B. Dual-pump and triple-pump CARS processes 1. Dual-pump CARS 2. Triple pump CARS C. Thermometry and species detection EXPERIMENTAL APPARATUS A. Initial experimental system 1. Laser.... Laser Alignment and Performance I . Nd: YAG laser 2. Narrow band dye laser (ND6000) alignment 3. Broad-band dye laser alignment B. Triple-pump CARS set-up 1. CARS phase-matching alignment 2. Diffusion flame burner C. Results I. Results from first...

Velur Natarajan, Viswanathan

2012-06-07T23:59:59.000Z

398

Fiber optic spectroscopic digital imaging sensor and method for flame properties monitoring  

DOE Patents [OSTI]

A system for real-time monitoring of flame properties in combustors and gasifiers which includes an imaging fiber optic bundle having a light receiving end and a light output end and a spectroscopic imaging system operably connected with the light output end of the imaging fiber optic bundle. Focusing of the light received by the light receiving end of the imaging fiber optic bundle by a wall disposed between the light receiving end of the fiber optic bundle and a light source, which wall forms a pinhole opening aligned with the light receiving end.

Zelepouga, Serguei A. (Hoffman Estates, IL); Rue, David M. (Chicago, IL); Saveliev, Alexei V. (Chicago, IL)

2011-03-15T23:59:59.000Z

399

A Study of Gasification of Municipal Solid Waste Using a Double Inverse Diffusion Flame Burner  

Science Journals Connector (OSTI)

A Study of Gasification of Municipal Solid Waste Using a Double Inverse Diffusion Flame Burner ... Furthermore, the experiences of the waste incineration industry driven in the past by regulatory as well as technical issues may facilitate their commercial potentials outside the common market, especially in highly populated developing countries such as Korea with scarce landfill sites. ... Recently, several new technologies that involve gasification or combinations of pyrolysis, combustion, and gasification processes are currently being brought into the market for energy-efficient, environmentally friendly and economically sound methods of thermal processing of wastes. ...

Tae-Heon Kwak; Seungmoon Lee; Sanjeev Maken; Ho-Chul Shin; Jin-Won Park; Young Done Yoo

2005-08-24T23:59:59.000Z

400

Conditional Moment Closure Modeling for a Three-Dimensional Turbulent Non-premixed Syngas Flame with a Cooling Wall  

Science Journals Connector (OSTI)

Conditional Moment Closure Modeling for a Three-Dimensional Turbulent Non-premixed Syngas Flame with a Cooling Wall ... In the experiment,(13) the burner is mounted to an air-cooled combustion chamber and the burner consists of a central fuel tube and an annular air tube. ... It can be seen that the velocity field at the pure-mixing entrance region is highly deflected by the flame holder, and the burned mixtures are partially impinged on the cooling wall (Tw = 600 K). ...

Gunhong Kim; Sungmo Kang; Yongmo Kim; Kwan-Soo Lee

2008-09-13T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Charged Vacuum Bubble Stability  

E-Print Network [OSTI]

A type of scenario is considered where electrically charged vacuum bubbles, formed from degenerate or nearly degenerate vacuua separated by a thin domain wall, are cosmologically produced due to the breaking of a discrete symmetry, with the bubble charge arising from fermions residing within the domain wall. Stability issues associated with wall tension, fermion gas, and Coulombic effects for such configurations are examined. The stability of a bubble depends upon parameters such as the symmetry breaking scale and the fermion coupling. A dominance of either the Fermi gas or the Coulomb contribution may be realized under certain conditions, depending upon parameter values.

J. R. Morris

1998-10-20T23:59:59.000Z

402

Towards a system of estates in virtual property  

Science Journals Connector (OSTI)

Virtual worlds such as Second Life have received a lot of press in the USA recently. As individuals and businesses participate in these virtual worlds, questions arise regarding the application of existing laws to their virtual world transactions. Many questions have arisen regarding the property rights of participants in virtual worlds, and a Second Life member recently sued Linden Research, the company that developed Second Life, alleging that Second Life converted his virtual property. The questions regarding the legal nature of virtual world assets tend to mirror the questions regarding intangible rights generally, as courts have tended to struggle over whether these rights are property rights or contract rights. In this paper, I propose that the principle of numerus clausus be applied to virtual property, so that courts faced with disputes over such assets will have mandatory property forms to which to resort. Such an approach would limit the ability of vendors of such rights to customise them through their contracts, which are commonly embodied in electronically presented standard forms.

Juliet M. Moringiello

2008-01-01T23:59:59.000Z

403

Effects of radiation on NO kinetics in turbulent hydrogen/air diffusion flames  

SciTech Connect (OSTI)

The authors describe a coupled radiation and NO kinetics calculation of turbulent hydrogen/air diffusion flame properties. Transport equations for mass, momentum, mixture fraction, enthalpy (sensible + chemical) including gas band radiation, and NO mass fraction are solved. NO kinetics is described by a one step thermal production mechanism. The local temperature is obtained by solving the enthalpy equation taking radiation loss from H{sub 2}O into consideration. Radiation/turbulence and chemical kinetics/turbulence interactions are treated using a clipped Gaussian probability density function (PDF) for the mixture fraction, and a delta PDF for the enthalpy. The source terms in the enthalpy and mass fraction of NO equations are treated using assumed PDF integration over the mixture fraction space. The results of the simulation are compared with existing measurements of the Emission Indices of NO (EINO) in turbulent H{sub 2}/air diffusion flames. The major conclusion of the paper is that coupled turbulence/radiation interactions should be taken into account while computing the EINO.

Sivathanu, Y.R.; Gore, J.P.; Laurendeau, N.M.

1997-07-01T23:59:59.000Z

404

Transported PDF Modeling of Nonpremixed Turbulent CO/H-2/N-2 Jet Flames  

SciTech Connect (OSTI)

Turbulent CO/H{sub 2}/N{sub 2} (“syngas”) flames are simulated using a transported composition probability density function (PDF) method. A consistent hybrid Lagrangian particle/Eulerian mesh algorithm is used to solve the modeled PDF transport equation. The model includes standard k–? turbulence, gradient transport for scalars, and Euclidean minimum spanning tree (EMST) mixing. Sensitivities of model results to variations in the turbulence model, the treatment of radiation heat transfer, the choice of chemical mechanism, and the PDF mixing model are explored. A baseline model reproduces the measured mean and rms temperature, major species, and minor species profiles reasonably well, and captures the scaling that is observed in the experiments. Both our results and the literature suggest that further improvements can be realized with adjustments in the turbulence model, the radiation heat transfer model, and the chemical mechanism. Although radiation effects are relatively small in these flames, consideration of radiation is important for accurate NO prediction. Chemical mechanisms that have been developed specifically for fuels with high concentrations of CO and H{sub 2} perform better than a methane mechanism that was not designed for this purpose. It is important to account explicitly for turbulence–chemistry interactions, although the details of the mixing model do not make a large difference in the results, within reasonable limits.

Zhao, xinyu; Haworth, D. C.; Huckaby, E. David

2012-01-01T23:59:59.000Z

405

Polymer/clay aerogel composites with flame retardant agents: Mechanical, thermal and fire behavior  

Science Journals Connector (OSTI)

Abstract Aerogel is a class of material characterized by its high void content and extreme lightness. Different polymer/clay aerogels have been prepared by a simply freeze–thaw process from a suspension with poly(vinyl alcohol) (PVOH) and clay (Na+-MMT). Low density polymer/clay aerogels modified with flame retardant agents were prepared using a similar approach. The addition of flame retardant agents slightly increased the apparent density of the final composites whereas the compression properties were reduced due to the decrease in the polymer/clay interfacial bonding. An exception was the sample containing Al(OH)3 that exhibited higher modulus and stress at maximum deformation. Regarding thermal properties, the presence of ammonium polyphosphate (APP) or silica gel (SG) significantly slowed the rate of aerogel decomposition at the temperature range from 250 °C to 500 °C while the onset of polymer decomposition was not affected. Fire behavior was analyzed through cone calorimeter suggesting that either the presence of Al(OH)3 or APP reduced the heat release rate of PVOH/clay systems.

Liang Wang; Miguel Sánchez-Soto; Maria Lluisa Maspoch

2013-01-01T23:59:59.000Z

406

Chemical kinetic considerations for postflame synthesis of carbon nanotubes in premixed flames using a support catalyst  

SciTech Connect (OSTI)

Multiwalled carbon nanotubes (MWCNTs) on a grid supported cobalt nanocatalyst were grown, by exposing it to combustion gases from ethylene/air rich premixed flames. Ten equivalence ratios ({phi}) were investigated, as follows: 1.37, 1.44, 1.47, 1.50, 1.55, 1.57, 1.62, 1.75, 1.82, and 1.91. MWCNT growth could be observed for the range of equivalence ratios between 1.45 and 1.75, with the best yield restricted to the range 1.5-1.6. A one-dimensional premixed flame code with a postflame heat loss model, including detailed chemistry, was used to estimate the gas phase chemical composition that favors MWCNT growth. The results of the calculations show that the mixture, including the water gas shift reaction, is not even in partial chemical equilibrium. Therefore, past discussions of compositional parameters that relate to optimum carbon nanotube (CNT) growth are revised to include chemical kinetic effects. Specifically, rapid departures of the water gas shift reaction from partial equilibrium and changes in mole fraction ratios of unburned C{sub 2} hydrocarbons to hydrogen correlate well with experimentally observed CNT yields. (author)

Gopinath, Prarthana; Gore, Jay [School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907 (United States)

2007-11-15T23:59:59.000Z

407

Proceedings of the international workshop on measurement and computation of turbulent nonpremixed flames  

SciTech Connect (OSTI)

This report documents the proceedings of the International Workshop on Measurement and Computation of Turbulent Nonpremixed Flames, held in Naples, Italy on July 26--27, 1996. Contents include materials that were distributed to participants at the beginning of the workshop, as well as a Summary of Workshop Accomplishments that was generated at the close to this Naples meeting. The Naples workshop involved sixty-one people from eleven countries. The primary objectives were: (1) to select a set of well-documented and relatively simple flames that would be appropriate for collaborative comparisons of model predictions; and (2) to specify common submodels to be used in these predictions, such that models for the coupling of turbulence and chemistry might be isolated and better understood. Studies involve hydrogen and natural gas fuels. These proceedings are also published on the Web and those interested in the ongoing process of data selection and model comparison should consult the workshop page for the most recent and complete information on these collaborative research efforts. The URL is: http://www/ca.sandia/gov/tdf/Workshop.html.

Barlow, R.S. [ed.

1996-10-01T23:59:59.000Z

408

Thermonuclear Flame Spreading on Rapidly Spinning Neutron Stars: Indications of the Coriolis Force?  

E-Print Network [OSTI]

Millisecond period brightness oscillations during the intensity rise of thermonuclear X-ray bursts are likely caused by an azimuthally asymmetric, expanding burning region on the stellar surface. The time evolution of the oscillation amplitude during the intensity rise encodes information on how the thermonuclear flames spread across the stellar surface. This process depends on properties of the accreted burning layer, surface fluid motions, and the surface magnetic field structure, and thus can provide insight into these stellar properties. We present two examples of bursts from different sources that show a decrease in oscillation amplitude during the intensity rise. Using theoretical modeling, we demonstrate that the observed amplitude evolution of these bursts is not well described by a uniformly expanding circular burning region. We further show that by including in our model the salient aspects of the Coriolis force (as described by Spitkovsky, Levin, and Ushomirsky) we can qualitatively reproduce the observed evolution curves. Our modeling shows that the evolutionary structure of burst oscillation amplitude is sensitive to the nature of flame spreading, while the actual amplitude values can be very useful to constrain some source parameters.

Sudip Bhattacharyya; Tod E. Strohmayer

2007-08-27T23:59:59.000Z

409

Stabilized chromium oxide film  

DOE Patents [OSTI]

Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150.ANG. are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

Garwin, Edward L. (Los Altos, CA); Nyaiesh, Ali R. (Palo Alto, CA)

1988-01-01T23:59:59.000Z

410

Orbit Stabilization of Nanosat  

SciTech Connect (OSTI)

An algorithm is developed to control a pulsed {Delta}V thruster on a small satellite to allow it to fly in formation with a host satellite undergoing time dependent atmospheric drag deceleration. The algorithm uses four short thrusts per orbit to correct for differences in the average radii of the satellites due to differences in drag and one thrust to symmetrize the orbits. The radial difference between the orbits is the only input to the algorithm. The algorithm automatically stabilizes the orbits after ejection and includes provisions to allow azimuthal positional changes by modifying the drag compensation pulses. The algorithm gives radial and azimuthal deadbands of 50 cm and 3 m for a radial measurement accuracy of {+-} 5 cm and {+-} 60% period variation in the drag coefficient of the host. Approaches to further reduce the deadbands are described. The methodology of establishing a stable orbit after ejection is illustrated in an appendix. The results show the optimum ejection angle to minimize stabilization thrust is upward at 86{sup o} from the orbital velocity. At this angle the stabilization velocity that must be supplied by the thruster is half the ejection velocity. An ejection velocity of 0.02 m/sat 86{sup o} gives an azimuthal separation after ejection and orbit stabilization of 187 m. A description of liquid based gas thrusters suitable for the satellite control is included in an appendix.

JOHNSON,DAVID J.

1999-12-01T23:59:59.000Z

411

Stability of the aether  

Science Journals Connector (OSTI)

The requirements for stability of a Lorentz violating theory are analyzed. In particular we conclude that Einstein-aether theory can be stable when its modes have any phase velocity, rather than only the speed of light as was argued in a recent paper.

William Donnelly and Ted Jacobson

2010-10-08T23:59:59.000Z

412

Stabilized chromium oxide film  

DOE Patents [OSTI]

Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150A are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.

Nyaiesh, A.R.; Garwin, E.L.

1986-08-04T23:59:59.000Z

413

Stability of the aether  

SciTech Connect (OSTI)

The requirements for stability of a Lorentz violating theory are analyzed. In particular we conclude that Einstein-aether theory can be stable when its modes have any phase velocity, rather than only the speed of light as was argued in a recent paper.

Donnelly, William; Jacobson, Ted [Center for Fundamental Physics, Department of Physics, University of Maryland at College Park, College Park, Maryland, 20742-4111 (United States)

2010-10-15T23:59:59.000Z

414

Daonity – Grid security from two levels of virtualization  

Science Journals Connector (OSTI)

The service oriented architecture of grid computing has been thoughtfully engineered to achieve a service level virtualization: not only should a grid be a virtual machine (also known as a virtual organization, VO) of unbounded computational power and storage capacity, but also should the virtual machine be serviceable in all circumstances independent from serviceability of any of its component. At present, a grid VO as a result of service level virtualization only is more or less confined to participants from scientific computing communities, i.e., can have a limited scale. It is widely agreed that for a grid to pool resources of truly unbounded scale, commercial enterprises and in particular server-abundant financial institutions, should also “go for the grid,” i.e., open up their servers for being used by grid VO constructions. We believed that it is today's inadequate strength of the grid security practice that is the major hurdle to prevent commercial organizations from serving and participating the grid. This article presents the work of Daonity which is our attempt to strengthening grid security. We identify that a security service which we name behavior conformity be desirable for grid computing. Behavior conformity for grid computing is an assurance that ad hoc related principals (users, platforms or instruments) forming a grid VO must each act in conformity with the rules for the VO constitution. We apply trusted computing technologies to achieve two levels of virtualization: resource virtualization and platform virtualization. The former is about behavior conformity in a grid VO and the latter, that in an operating system. With these two levels of virtualization working together it is possible to build a grid of truly unbounded scale by VO including servers from commercial organizations.

Haibo Chen; Jieyun Chen; Wenbo Mao; Fei Yan

2007-01-01T23:59:59.000Z

415

Stability characteristics of some shale and coal liquids. Final report. [Thermal and storage stability  

SciTech Connect (OSTI)

Liquid hydrocarbon fuels derived from coal and from oil shale were made available for characterization and thermal and storage stability investigations. The coal-derived liquids identified as naphthas from No. 6 Illinois and Wyodak coals produced by the Exxon Donor Solvent process contained high concentrations of oxygen, nitrogen, and sulfur compounds and were considered to be unrefined synthetic crudes. These materials were found to be relatively unstable in storage. The shale-derived fuels were refined to meet the requirements of military specification jet fuels JP-8 and JP-5 and marine diesel fuel (DFM). Virtually all the specification requirements were met and the fuels were found to be thermally and storage stable. During 32-week, 43/sup 0/C storage tests conducted on these liquids, periodic measurements were made of precipitate fuel-insolubles, fuel-soluble gum, dissolved oxygen content and peroxide number. The liquids were analyzed, in some instances, by infrared, NMR, and uv spectroscopy, before and after the 32-week storage test with little or no change being observed in the bulk liquid samples. Shale-derived liquid hydrocarbons have been refined to meet current specification requirements for hydrocarbon fuels, and it appears that coal-derived liquids can also be refined to meet requirements for performance and storage stability.

Bowden, J.N.

1980-11-01T23:59:59.000Z

416

Effect of syngas composition and CO2-diluted oxygen on performance of a premixed swirl-stabilized combustor.  

SciTech Connect (OSTI)

Future energy systems based on gasification of coal or biomass for co-production of electrical power and fuels may require gas turbine operation on unusual gaseous fuel mixtures. In addition, global climate change concerns may dictate the generation of a CO{sub 2} product stream for end-use or sequestration, with potential impacts on the oxidizer used in the gas turbine. In this study the operation at atmospheric pressure of a small, optically accessible swirl-stabilized premixed combustor, burning fuels ranging from pure methane to conventional and H{sub 2}-rich and H{sub 2}-lean syngas mixtures is investigated. Both air and CO{sub 2}-diluted oxygen are used as oxidizers. CO and NO{sub x} emissions for these flames have been determined from the lean blowout limit to slightly rich conditions ({phi} - 1.03). In practice, CO{sub 2}-diluted oxygen systems will likely be operated close to stoichiometric conditions to minimize oxygen consumption while achieving acceptable NO{sub x} performance. The presence of hydrogen in the syngas fuel mixtures results in more compact, higher temperature flames, resulting in increased flame stability and higher NO{sub x} emissions. Consistent with previous experience, the stoichiometry of lean blowout decreases with increasing H{sub 2} content in the syngas. Similarly, the lean stoichiometry at which CO emissions become significant decreases with increasing H{sub 2} content. For the mixtures investigated, CO emissions near the stoichiometric point do not become significant until {phi} > 0.95. At this stoichiometric limit, CO emissions rise more rapidly for combustion in O{sub 2}-CO{sub 2} mixtures than for combustion in air.

Williams, Timothy C.; Shaddix, Christopher R.; Schefer, Robert W.

2007-01-01T23:59:59.000Z

417

VONEX: A Novel Approach to Establishing Open Virtual Money Exchange Regime  

E-Print Network [OSTI]

VONEX: A Novel Approach to Establishing Open Virtual Money Exchange Regime Angelina Chow Department Establishing an open virtual money exchange regime is a novel idea but rarely discussed. This paper provides a pioneer research on virtual money exchange (VONEX) approach, aiming to facilitate the exchange of virtual

Guo, Jingzhi

418

Bilateral Teleoperation of Wheeled Mobile Robot with Time Delay using Virtual Image Robot  

E-Print Network [OSTI]

Bilateral Teleoperation of Wheeled Mobile Robot with Time Delay using Virtual Image Robot Yasunori of wheeled mobile robot with time delay using the virtual image robot. In this paper, we introduce the virtual image robot as a master robot. The human operator commands the virtual image robot, the slave

419

Visualization of folding in marble outcrops, Connemara, western Ireland: An application of virtual outcrop technology  

Science Journals Connector (OSTI)

...to have remote access (via intranet or Internet) to course content...Benefits of Virtual Outcrop Technology Virtual outcrops offer students...shows how virtual outcrop technology could provide good structural...possible from virtual outcrop technology. During the project, the...

420

Categorisation of data management solutions for heterogeneous data in collaborative virtual engineering  

Science Journals Connector (OSTI)

Computer based virtual development is the basis of product engineering, called virtual engineering. The increasing demand of virtual engineering solutions for new domains and companies leads to a huge width of approaches in this area. To enhance the ... Keywords: PDM, PLM, collaboration, data management, exchange, integration, virtual engineering

Stephan Vornholt; Ingolf Geist; Yuexiao Li

2010-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

OH-PLIF Measurements of High-Pressure, Hydrogen Augmented Premixed Flames in the SimVal Combustor  

SciTech Connect (OSTI)

Planar Laser Induced Fluorescence (PLIF) measurements of the hydroxyl radical in lean, premixed natural gas flames augmented with hydrogen are presented. The experiments were conducted in the SimVal combustor at the National Energy Technology Laboratory (NETL) at operating pressures from 1 to 8 atmospheres. The data, which was collected in a combustor with well controlled boundary conditions, is intended to be used for validating Computational Fluid Dynamics (CFD) models under conditions directly relevant to land-based gas turbine engines. The images, which show significant effects of hydrogen on local flame quenching are discussed in terms of a turbulent premixed combustion regime and non-dimensional parameters such as Karlovitz number. Pressure was found to thin the OH region, but only had a secondary effect on overall flame shape compared to the effects of hydrogen addition which was found to decrease local quenching and shorten the turbulent flame brush. A method to process the individual images based on local gradients of fluorescence intensity is proposed and results are presented. Finally, the results of several Large Eddy Simulations (LES) are presented and compared to the experimental data in an effort to understand the issues related to model validation, especially for simulations that do not include OH as an intermediate species.

Strakey, P.A.; Woodruff, S.D.; Williams, T.C. (Sandia); Schefer, R.W. (Sandia)

2007-01-01T23:59:59.000Z

422

Acoustic near-field characteristics of a conical, premixed flame Doh-Hyoung Lee and Tim C. Lieuwena)  

E-Print Network [OSTI]

system failure. They gener- ally occur at frequencies associated with the combustor's natural it is influenced by oscillation frequency, combustor geometry, flame length and temperature ratio. The results processing,1 solid and liquid rockets,2,3 ramjets,4 afterburners, and land-based gas turbines.5

Lieuwen, Timothy C.

423

Assessment of kinetic modeling for lean H2/CH4/O2/diluent flames at high pressures  

E-Print Network [OSTI]

) and HO2 + H with the main branching reactions. Methane addition is shown to influence the pressure: Hydrogen; Methane; Syngas; Flame speed; Chemical mechanism 1. Introduction The H2/O2 reaction system CO, CO2, H2O, CH4 and other small hydrocarbons (synthetic gas or "syngas") from coal or biomass

Ju, Yiguang

424

Lawrence Berkeley National Laboratory report LBNL-725E 1 A New Type of Steady and Stable, Laminar, Premixed Flame  

E-Print Network [OSTI]

, Premixed Flame in Ultra-Lean, Hydrogen-Air Combustion Joseph F. Grcara a Center for Computational Science and Engineering Lawrence Berkeley National Laboratory Berkeley, CA 94720-8142, USA Abstract Ultra-lean, hydrogen propagating cells. These cells were the original meaning of the word "flamelet" when they were observed

425

A STUDY ON SPHERICAL EXPANDING FLAME SPEEDS OF METHANE, ETHANE, AND METHANE/ETHANE MIXTURES AT ELEVATED PRESSURES  

E-Print Network [OSTI]

High-pressure experiments and chemical kinetics modeling were performed for laminar spherically expanding flames for methane/air, ethane/air, methane/ethane/air and propane/air mixtures at pressures between 1 and 10 atm and equivalence ratios...

De Vries, Jaap

2010-07-14T23:59:59.000Z

426

NETL: Gasification Systems - Advanced Virtual Energy Simulation Training  

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

Advanced Virtual Energy Simulation Training And Research (AVESTAR(tm)) Facility Advanced Virtual Energy Simulation Training And Research (AVESTAR(tm)) Facility Project No: Adv Gas-FY131415 Task 6 Developed as a part of NETL's initiative to advance new clean coal technology, the Advanced Virtual Energy Simulation Training And Research (AVESTARTM) Center is focused on training engineers and energy plant operators in the efficient, productive, and safe operation of highly efficient power generation systems that also protect the environment. Comprehensive dynamic simulator-based instruction better prepares operators and engineers to manage advanced energy plants according to economic constraints while minimizing or avoiding the impact of any potentially harmful, wasteful, or inefficient events. Advanced Virtual Energy Simulation Training and Research Center - AVESTAR

427

Building Energy Software Tools Directory: IES Virtual Environment  

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

IES Virtual Environment IES Virtual Environment IES Virtual Environment Logo The IES Virtual Environment (IESVE) is a powerful, in-depth suite of building performance analysis tools. It allows the design and operation of comfortable buildings that consume significantly less energy. Whether working on a new build or renovation project, the VE allows designers to test different options, identify best passive solutions, compare low-carbon & renewable technologies, and draw conclusions on energy use, CO2 emissions, occupant comfort, and much more. There are various tools in the suite; each designed to provide sustainable analysis at levels suitable for different design team members and design stages. All utilise our Apache dynamic thermal simulation engine, and an integrated central data model, which has direct links to SketchUp™,

428

Virtual Reality as a Support Tool for Ergonomic Style Convergence  

E-Print Network [OSTI]

Virtual Reality as a Support Tool for Ergonomic ­ Style Convergence Multidisciplinary Interaction and this paper presents a case study: the design of a support tool for ergonomic-style convergence. Categories

429

Power in Collaboration: National Energy Literacy Virtual Meet-Up  

Broader source: Energy.gov [DOE]

The webinar will be a dynamic virtual conversation of ongoing efforts from across the country in utilizing the Department of Energy's Energy Literacy Framework to address one of our nation's...

430

Knowledge integration in virtual teams: the potential role of KMS  

Science Journals Connector (OSTI)

Virtual teams are becoming a preferred mechanism for harnessing, integrating, and applying knowledge that is distributed across organizations and in pockets of collaborative networks. In this article we recognize that knowledge application, among the ...

Maryam Alavi; Amrit Tiwana

2002-10-01T23:59:59.000Z

431

Introduction to the Virtual Issue of Energy & Fuels on Biofuels  

Science Journals Connector (OSTI)

Introduction to the Virtual Issue of Energy & Fuels on Biofuels ... A general modeling framework conceived to drive the decision-making process for the strategic design of biofuel supply networks is presented. ...

Robert S. Weber

2010-11-11T23:59:59.000Z

432

BioenergizeME Virtual Science Fair: Environmental benefit of Bioenergy  

Broader source: Energy.gov [DOE]

This infographic was created by students from Sun Valley High School in Aston, PA, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

433

BioenergizeME Virtual Science Fair: Bioenergy Careers  

Broader source: Energy.gov [DOE]

This infographic was created by students from Sun Valley High School in Aston, PA, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

434

BioenergizeME Virtual Science Fair: Microbiology and Bioenergy  

Broader source: Energy.gov [DOE]

This infographic was created by students from Toledo High School in Toledo, OR, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

435

BioenergizeME Virtual Science Fair: History of Biomass  

Broader source: Energy.gov [DOE]

This infographic was created by students from Daniel Boone Area High School in Birdsboro, PA, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

436

BioenergizeME Virtual Science Fair: Environmental Impacts  

Broader source: Energy.gov [DOE]

This infographic was created by students from Sun Valley High School in Aston, PA, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

437

BioenergizeME Virtual Science Fair: Bioenegy Benefits Environmental Forestry  

Broader source: Energy.gov [DOE]

This infographic was created by students from Sun Valley High School in Aston, PA, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

438

BioenergizeME Virtual Science Fair: Biomass History A timeline  

Broader source: Energy.gov [DOE]

This infographic was created by students from Sun Valley High School in Aston, PA, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

439

BioenergizeME Virtual Science Fair: History of Bioenergy  

Broader source: Energy.gov [DOE]

This infographic was created by students from Sun Valley High School in Aston, PA, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

440

BioenergizeME Virtual Science Fair: Environmental Impacts of Bioenergy  

Broader source: Energy.gov [DOE]

This infographic was created by students from Sun Valley High School in Aston, PA, as part of the U.S. Department of Energy-BioenergizeME Virtual Science Fair.

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Promoting Sustainability Awareness through Energy Engaged Virtual Communities of Construction  

E-Print Network [OSTI]

Promoting Sustainability Awareness through Energy Engaged Virtual Communities of Construction to demolition. Sustainability knowledge is #12;Promoting Sustainability Awareness through Energy EngagedH@cf.ac.uk Abstract. Sustainability requires the engagement of every single constituent of the "building" product

Paris-Sud XI, Université de

442

Populating reconstructed archaeological sites with autonomous virtual humans  

Science Journals Connector (OSTI)

Significant multidisciplinary efforts combining archaeology and computer science have yielded virtual reconstructions of archaeological sites for visualization. Yet comparatively little attention has been paid to the difficult problem of populating these ...

Wei Shao; Demetri Terzopoulos

2006-08-01T23:59:59.000Z

443

The (human) science of medical virtual learning environments  

Science Journals Connector (OSTI)

...federal grant from the Department of the Navy's Office of Naval Research, the Pulse!! Virtual Learning...populations (p. 343). Simulation design must become a science, a human-centred science, driven by the publication of good, peer-reviewed...

2011-01-01T23:59:59.000Z

444

VIMS2002 International Symposium on Virtual and Intelligent Measurement Systems  

E-Print Network [OSTI]

VIMS2002 International Symposium on Virtual and Intelligent Measurement Systems Mt. Alyeska Resort be used to propagate the uncertainty. Smith et al. [14] have developed the equations for a propagation

Payeur, Pierre

445

Technology adaptation and boundary management in bona fide virtual groups.  

E-Print Network [OSTI]

In this research project composed of multiple case studies, I focused on how bona fide virtual groups appropriated multiple media to facilitate group boundary construction and boundary management, which are preconditions of group identity formation...

Zhang, Huiyan

2006-04-12T23:59:59.000Z

446

Context-based Distributed Regression in Virtual Organizations  

E-Print Network [OSTI]

, Ireland {yan.xing, michael.madden, jim.duggan, gerard.lyons}@nuigalway.ie Abstract. The characteristics of Internet and Intranet, there are virtual organizations in different domains such as a loosely coupled

Madden, Michael

447

Virtual cathode microwave generator having annular anode slit  

DOE Patents [OSTI]

A microwave generator is provided for generating microwaves substantially from virtual cathode oscillation. Electrons are emitted from a cathode and accelerated to an anode which is spaced apart from the cathode. The anode has an annular slit therethrough effective to form the virtual cathode. The anode is at least one range thickness relative to electrons reflecting from the virtual cathode. A magnet is provided to produce an optimum magnetic field having the field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit. The magnetic field, however, does permit the reflected electrons to axially diverge from the annular beam. The reflected electrons are absorbed by the anode in returning to the real cathode, such that substantially no reflexing electrons occur. The resulting microwaves are produced with a single dominant mode and are substantially monochromatic relative to conventional virtual cathode microwave generators.

Kwan, Thomas J. T. (Los Alamos, NM); Snell, Charles M. (Los Alamos, NM)

1988-01-01T23:59:59.000Z

448

Virtual Reality-Based Simulation of Endoscopic Surgery  

Science Journals Connector (OSTI)

Virtual reality (VR)-based surgical simulator systems offer a very elegant approach to enriching and enhancing traditional training in endoscopic surgery. However, while a number of VR simulator systems have been proposed and realized in the past few ...

G. Székely; Ch. Brechbühler; J. Dual; R. Enzler; J. Hug; R. Hutter; N. Ironmonger; M. Kauer; V. Meier; P. Niederer; A. Rhomberg; P. Schmid; G. Schweitzer; M. Thaler; V. Vuskovic; G. Tröster; U. Haller; M. Bajka

2000-06-01T23:59:59.000Z

449

Hadley Cell Dynamics in a Virtually Dry Snowball Earth Atmosphere  

Science Journals Connector (OSTI)

The Hadley cell of a virtually dry snowball Earth atmosphere under equinox insolation is studied in a comprehensive atmospheric general circulation model. In contrast to the Hadley cell of modern Earth, momentum transport by dry convection, which ...

Aiko Voigt; Isaac M. Held; Jochem Marotzke

2012-01-01T23:59:59.000Z

450

Software Enabled Virtually Variable Displacement Pumps -Theoretical and Experimental Studies  

E-Print Network [OSTI]

Software Enabled Virtually Variable Displacement Pumps - Theoretical and Experimental Studies the functional equivalent of a variable displacement pump. This approach combines a fixed displacement pump valve control, without many of the shortcomings of commercially available variable displacement pumps

Li, Perry Y.

451

The Large Hadron Collider - At Discover's Horizon | Virtual LHC...  

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

Virtual LHC Lectures These past lectures might give you a better idea of how to plan your upcoming LHC presentation. After you give your lecture, if a video of your presentation or...

452

Experiments at The Virtual National Laboratory for Heavy Ion Fusion  

E-Print Network [OSTI]

Heavy Ion Beam Driven Fusion Reactor Study", KfK 3840,between the reactor chamber wall and the fusion target. Thereactor chambers. INTRODUCTION The USA Virtual National Laboratory for Heavy Ion Fusion

2000-01-01T23:59:59.000Z

453

U.S.-U.K. Collaboration on Virtual Plant Simulation  

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

U.S.-U.K. Collaboration on U.S.-U.K. Collaboration on Virtual Plant Simulation Background Under the auspices of the U.S.-U.K. Memorandum of Understanding and Implementing Agreement for Fossil Energy Research and Technology Development, the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) participated in a three-year collaboration on virtual plant simulation with a project team supported by the Department for Business, Enterprise & Regulatory Reform in

454

Virtual environmental applications for buried waste characterization technology evaluation report  

SciTech Connect (OSTI)

The project, Virtual Environment Applications for Buried Waste Characterization, was initiated in the Buried Waste Integrated Demonstration Program in fiscal year 1994. This project is a research and development effort that supports the remediation of buried waste by identifying and examining the issues, needs, and feasibility of creating virtual environments using available characterization and other data. This document describes the progress and results from this project during the past year.

NONE

1995-05-01T23:59:59.000Z

455

Stability of Coupling Algorithms  

E-Print Network [OSTI]

INTRODUCTION AND MOTIVATION : : : : : : : : : : : : : 1 A. Approaches to solving a coupled system . . . . . . . . . . . 3 B. Common terminology . . . . . . . . . . . . . . . . . . . . . 5 C. Classi cation of coupling algorithms . . . . . . . . . . . . . 7 1... equal, cA = cB = mA = mB = 1 and with dissipation, = 0:5 : : : : : : : : : : : : : : : : 26 10 Conditional stability observed with cA > cB. The material prop- erties: cA = 100; cB = 1; mA = mB = 1; = 1 : : : : : : : : : : : : : 27 11 An unstable...

Akkasale, Abhineeth

2012-07-16T23:59:59.000Z

456

Improved roof stabilization technologies  

SciTech Connect (OSTI)

Decontamination and decommissioning (D and D) activities require that personnel have access to all areas of structures, some of which are more than 40 years old. In many cases, these structures have remained in a standby condition for up to 10 years; few preventative maintenance activities have been performed on them because of lack of funding or a defined future plan of action. This situation has led to deteriorated building conditions, resulting in potential personnel safety hazards. In addition, leaky roofs allow water to enter the buildings, which can cause the spread of contamination and increase building deterioration, worsening the already unsafe working conditions. To ensure worker safety and facilitate building dismantlement, the assessment of roof stabilization techniques applicable to US Department of Energy (DOE) structures has become an important issue. During Fiscal year 1997 (FY97), a comprehensive reliability-based model for the structural stabilization analysis of roof system in complex structures was developed. The model consists of three major components: a material testing method, a deterministic structural computer model, and a reliability-based optimization, and probabilistic analyses of roof structures can be implemented. Given site-specific needs, this model recommends the most appropriate roof stabilization system. This model will give not only an accurate evaluation of the existing roof system in complex structures, but it will also be a reliable method to aid the decision-making process. This final report includes in its appendix a Users` Manual for the Program of Deterministic and Reliability Analysis of Roof Structures.

Ebadian, M.A.

1998-01-01T23:59:59.000Z

457

The Impact of Biomass Fuels on Flame Structure and Pollutant Formation during Biomass Cofiring Combustion.  

E-Print Network [OSTI]

??Cofiring of biomass in pulverized coal boilers for large-scale power generation requires that current combustion standards of stability, reliability, emission and fuel conversion efficiency are… (more)

Holtmeyer, Melissa Lauren

2012-01-01T23:59:59.000Z

458

Generation IV Nuclear Energy Systems Construction Cost Reductions through the Use of Virtual Environments - Task 5 Report: Generation IV Reactor Virtual Mockup Proof-of-Principle Study  

SciTech Connect (OSTI)

Task 5 report is part of a 3 year DOE NERI-sponsored effort evaluating immersive virtual reality (CAVE) technology for design review, construction planning, and maintenance planning and training for next generation nuclear power plants. Program covers development of full-scale virtual mockups generated from 3D CAD data presented in a CAVE visualization facility. Created a virtual mockup of PBMR reactor cavity and discussed applications of virtual mockup technology to improve Gen IV design review, construction planning, and maintenance planning.

Timothy Shaw; Anthony Baratta; Vaughn Whisker

2005-02-28T23:59:59.000Z

459

CONTROL OF POLLUTANT EMISSIONS IN NATURAL GAS DIFFUSION FLAMES BY USING CASCADE BURNERS  

SciTech Connect (OSTI)

The advanced CFDRC software package was installed on a SUN-SPARC dual processor workstation (UTPA funded). The literature pertinent to the project was collected. The physical model was set and all parameters and variables were identified. Based on the physical model, the geometric modeling and grid generation processes were performed using the CFD-GEOM (Interactive Geometric Modeling and Grid Generation software). A total number of 11160 cells (248 x 45) were generated. The venturis in the cascade were modeled as two-dimensional axisymmetric convergent nozzles around the jet. With the cascade being added to the jet, the geometric complexity of the problem increased; which required multi-domain structured grid systems to be connected and matched on the boundaries. The natural gas/propane jet diffusion flame is being numerically analyzed. The numerical computations are being conducted using the CFDRC-ACE+ (advanced computational environment) software package. The results are expected soon.

Ala Qubbaj

2001-03-30T23:59:59.000Z

460

Chemiluminescence-based multivariate sensing of local equivalence ratios in premixed atmospheric methane-air flames  

SciTech Connect (OSTI)

Chemiluminescence emissions from OH*, CH*, C2, and CO2 formed within the reaction zone of premixed flames depend upon the fuel-air equivalence ratio in the burning mixture. In the present paper, a new partial least square regression (PLS-R) based multivariate sensing methodology is investigated and compared with an OH*/CH* intensity ratio-based calibration model for sensing equivalence ratio in atmospheric methane-air premixed flames. Five replications of spectral data at nine different equivalence ratios ranging from 0.73 to 1.48 were used in the calibration of both models. During model development, the PLS-R model was initially validated with the calibration data set using the leave-one-out cross validation technique. Since the PLS-R model used the entire raw spectral intensities, it did not need the nonlinear background subtraction of CO2 emission that is required for typical OH*/CH* intensity ratio calibrations. An unbiased spectral data set (not used in the PLS-R model development), for 28 different equivalence ratio conditions ranging from 0.71 to 1.67, was used to predict equivalence ratios using the PLS-R and the intensity ratio calibration models. It was found that the equivalence ratios predicted with the PLS-R based multivariate calibration model matched the experimentally measured equivalence ratios within 7%; whereas, the OH*/CH* intensity ratio calibration grossly underpredicted equivalence ratios in comparison to measured equivalence ratios, especially under rich conditions ( > 1.2). The practical implications of the chemiluminescence-based multivariate equivalence ratio sensing methodology are also discussed.

Tripathi, Markandey M.; Krishnan, Sundar R.; Srinivasan, Kalyan K.; Yueh, Fang-Yu; Singh, Jagdish P.

2012-03-01T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Serious Games & Virtual Environments for Educational and Entertainment Speaker: Dr Daniela M Romano, 3D Graphics and Virtual Reality Group, Computer Science, University  

E-Print Network [OSTI]

be sustained while experiencing them. In this presentation serious games and virtual environments applicationSerious Games & Virtual Environments for Educational and Entertainment Speaker: Dr Daniela M Romano learning to ensure that the learning is integrated within `gameplay'. Virtual Environments are 3D graphical

Romano, Daniela

462

Virtual Simulation of Vision 21 Energy Plants  

SciTech Connect (OSTI)

The Vision 21 Energy plants will be designed by combining several individual power, chemical, and fuel-conversion technologies. These independently developed technologies or technology modules can be interchanged and combined to form the complete Vision 21 plant that achieves the needed level of efficiency and environmental performance at affordable costs. The knowledge about each technology module must be captured in computer models so that the models can be linked together to simulate the entire Vision 21 power plant in a Virtual Simulation environment. Eventually the Virtual Simulation will find application in conceptual design, final design, plant operation and control, and operator training. In this project we take the first step towards developing such a Vision 21 Simulator. There are two main knowledge domains of a plant--the process domain (what is in the pipes), and the physical domain (the pipes and equipment that make up the plant). Over the past few decades, commercial software tools have been developed for each of these functions. However, there are three main problems that inhibit the design and operation of power plants: (1) Many of these tools, largely developed for chemicals and refining, have not been widely adopted in the power industry. (2) Tools are not integrated across functions. For example, the knowledge represented by computational fluid dynamics (CFD) models of equipment is not used in process-level simulations. (3) No tool exists for readily integrating the design and behavioral knowledge about components. These problems must be overcome to develop the Vision 21 Simulator. In this project our major objective is to achieve a seamless integration of equipment-level and process-level models and apply the integrated software to power plant simulations. Specifically we are developing user-friendly tools for linking process models (Aspen Plus) with detailed equipment models (FLUENT CFD and other proprietary models). Such integration will ensure that consistent and complete knowledge about the process is used for design and optimization. The technical objectives of the current project are the following: Develop a software integration tool called the V21-Controller to mediate the information exchange between FLUENT, other detailed equipment models, and Aspen Plus. Define and publish software interfaces so that software and equipment vendors may integrate their computer models into the software developed in this project. Demonstrate the application of the integrated software with two power plant simulations, one for a conventional steam plant and another for an advanced power cycle. The project was started in October 2000. Highlights of the accomplishments during the first year of the project are the following: Formed a multi-disciplinary project team consisting of chemical and mechanical engineers; computer scientists; CFD, process simulation, and plant design software developers; and power plant designers. Developed a prototype of CFD and process model integration: a stirred tank reactor model based on FLUENT was inserted into a flow sheet model based on Aspen Plus. The prototype was used to show the effect of shaft speed (a parameter in the CFD model) on the product yield and purity (results of process simulation). This demonstrated the optimization of an equipment item in the context of the entire plant rather than in isolation. Conducted a user survey and wrote the User Requirements, Software Requirements and Software Design documents for the V21-Controller. Adopted CAPE-OPEN standard interfaces for communications between equipment and process models. Developed a preliminary version of the V21-Controller based on CAPE-OPEN interfaces. Selected one unit of an existing conventional steam plant (Richmond Power & Light) as the first demonstration case and developed an Aspen Plus model of the steam-side of the unit. A model for the gas-side of the unit, based on ALSTOM's proprietary model INDVU, was integrated with the Aspen Plus model. An industrial Advisory Board was formed to guide the software deve

Syamlal, Madhava; Felix, Paul E.; Osawe, Maxwell O. (Fluent Inc.); Fiveland, Woodrow A.; Sloan, David G. (ALSTOM Power); Zitney, Stephen E. (Aspen Technology, Inc.); Joop, Frank (Intergraph Corporation); Cleetus, Joseph; Lapshin, Igor B. (Concurrent Engineering Research Center, West Virginia University)

2001-11-06T23:59:59.000Z

463

Stabilizing quantum information  

Science Journals Connector (OSTI)

The dynamical-algebraic structure underlying all the schemes for quantum information stabilization is argued to be fully contained in the reducibility of the operator algebra describing the interaction with the environment of the coding quantum system. This property amounts to the existence of a nontrivial group of symmetries for the global dynamics. We provide a unified framework that allows us to build systematically additional classes of error correcting codes and noiseless subsystems. It is shown that by using symmetrization strategies one can artificially produce noiseless subsystems supporting universal quantum computation.

Paolo Zanardi

2000-12-05T23:59:59.000Z

464

Flame pyrolysis – a preparation route for ultrafine pure ?-Fe2O3 powders and the control of their particle size and properties  

Science Journals Connector (OSTI)

Highly dispersed ?-Fe2O3 powders with particle sizes down to 5 nm were directly synthesized by combustion of solutions of iron pentacarbonyl or iron(III) acetylacetonate in toluene in an oxyhydrogen flame. The .....

S GRIMM; M SCHULTZ; S BARTH; R MULLER

465

Enhancements of a Combustion Vessel to Determine Laminar Flame Speeds of Hydrocarbon Blends with Helium Dilution at Elevated Temperatures and Pressures  

E-Print Network [OSTI]

in conjunction with National University of Ireland Galway compared favorably with the data, while the literature data showed discrepancies at stoichiometric to rich conditions. An in-depth flame speed uncertainty analysis yielded a wide range of values from 0...

Plichta, Drew

2013-04-03T23:59:59.000Z

466

The study of flame dynamics and structures in an industrial-scale gas turbine combustor using digital data processing and computer vision techniques  

Science Journals Connector (OSTI)

In this paper, a combined effort has been made to study the flame dynamics and structures in a gas turbine combustor using a range of imaging and digital data processing techniques. The acoustic characteristics of the combustor have been investigated extensively. It is found that there is no straightforward way to alter the peak frequency of one of the peculiar combustion modes of the rig. High speed imaging is applied to investigate the flame dynamics and quantitative analysis of the image database has been demonstrated. The results show that the frequency spectrum of the mean pixel image intensity of seeded flame is in good agreement with the acoustic spectrum. To recover the loss in depth information present in conventional imaging technique, both the optical and digital stereo imaging techniques have been applied. The important flame position relative to the combustion chamber could be resolved.

W.B. Ng; K.J. Syed; Y. Zhang

2005-01-01T23:59:59.000Z

467

Virtual university-oriented cooperative mobile agent middleware  

Science Journals Connector (OSTI)

The autonomy, cooperativity, intelligence and mobility of mobile agents make them overcome the weakness of the traditional distributed computation mode of C/S and B/S, and bring new innovative solutions to the collaborative teaching, collaborative learning and collaborative management in virtual universities. However, nowadays most of the research in mobile agent technology in terms of the Virtual University is mostly focused on a certain application for some particular users. As a result, these researches do not provide an effective control mechanism for the universal management of multiapplication agents that work for the multiusers with multicharacters. This has prevented the implementation and promulgation of agent technology in virtual universities. As far as such insufficiency is concerned, this paper demonstrates its own solution. In this paper, a Virtual University-Oriented cooperative Mobile Agent Middleware (VUMAM) and a Virtual University framework based on VUMAM are designed. In addition, the paper discusses the assignment of agent characters and function, agent naming, the control mechanism of cooperative agents and the extendability of VUMAM.

Wenqing Peng; Yuanming Luo

2006-01-01T23:59:59.000Z

468

A Detailed Chemical Kinetic Reaction Mechanism for Oxidation of Four Small Alkyl Esters in Laminar Premixed Flames  

SciTech Connect (OSTI)

A detailed chemical kinetic reaction mechanism has been developed for a group of four small alkyl ester fuels, consisting of methyl formate, methyl acetate, ethyl formate and ethyl acetate. This mechanism is validated by comparisons between computed results and recently measured intermediate species mole fractions in fuel-rich, low pressure, premixed laminar flames. The model development employs a principle of similarity of functional groups in constraining the H atom abstraction and unimolecular decomposition reactions in each of these fuels. As a result, the reaction mechanism and formalism for mechanism development are suitable for extension to larger oxygenated hydrocarbon fuels, together with an improved kinetic understanding of the structure and chemical kinetics of alkyl ester fuels that can be extended to biodiesel fuels. Variations in concentrations of intermediate species levels in these flames are traced to differences in the molecular structure of the fuel molecules.

Westbrook, C K; Pitz, W J; Westmoreland, P R; Dryer, F L; Chaos, M; Osswald, P; Kohse-Hoinghaus, K; Cool, T A; Wang, J; Yang, B; Hansen, N; Kasper, T

2008-02-08T23:59:59.000Z

469

Superconductor stability 90: A review  

SciTech Connect (OSTI)

This paper reviews some recent developments in the field of stability of superconductors. The main topics dealt with are hydrodynamic phenomena in cable-in-conduit superconductors, namely, multiple stability, quench pressure, thermal expulsion, and thermal hydraulic quenchback, traveling normal zones in large, composite conductors, such as those intended for SMES, and the stability of vapor-cooled leads made of high-temperature superconductors. 31 refs., 5 figs.

Dresner, L.

1990-01-01T23:59:59.000Z

470

Stability of 114298 Against Fission  

Science Journals Connector (OSTI)

The formalism of Siemens and Bethe concerning the stability of 114298 gives different conclusions depending on the mass formula used in obtaining the fissionability parameter.

Cheuk-Yin Wong

1967-08-07T23:59:59.000Z

471

Aerodynamic Drag and Gyroscopic Stability  

E-Print Network [OSTI]

This paper describes the effects on aerodynamic drag of rifle bullets as the gyroscopic stability is lowered from 1.3 to 1.0. It is well known that a bullet can tumble for stability less than 1.0. The Sierra Loading Manuals (4th and 5th Editions) have previously reported that ballistic coefficient decreases significantly as gyroscopic stability, Sg, is lowered below 1.3. These observations are further confirmed by experiments reported here. Measured ballistic coefficients were compared with gyroscopic stabilities computed using the Miller Twist Rule for nearly solid metal bullets with uniform density and computed using the Courtney-Miller formula for plastic-tipped bullets. The relationship between Sg and drag may be used to test the applicability of existing gyroscopic stability formulas for given bullet designs and to evaluate the accuracy of alternate formulas in cases where the existing stability formulas are not as accurate. The most definitive test of formulas predicting stability will always be observation of whether bullets tumble under given conditions. However, observations of drag changes provide valuable supplemental information because they suggest changes in stability as conditions change. Use of a continuous variable (drag) rather than a binary variable (tumbling) allows insight into stability over a range of conditions where the binary variable does not change.

Elya R. Courtney; Michael W. Courtney

2014-10-16T23:59:59.000Z

472

Unlocking Customer Value: The Virtual Power Plant | Department of Energy  

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

Unlocking Customer Value: The Virtual Power Plant Unlocking Customer Value: The Virtual Power Plant Unlocking Customer Value: The Virtual Power Plant The utility world has changed drastically in the last 10 years. New technologies like Smart Meters and fully functional Smart Grid concepts have made large inroads into the utility space and no one should want to be left behind. Utilities also face additional pressures from regulatory bodies who are continuing to encourage carbon reduction and greater customer flexibility. Utilities need to balance these new requirements with the financial obligations of providing reliable power (at a reasonable price) while attempting to meet shareholder expectations. Each of these goals are not necessarily complimentary, thus utilities need to determine how to address each one.

473

Virtual Reading Room prior to 2000 | National Nuclear Security  

National Nuclear Security Administration (NNSA)

prior to 2000 | National Nuclear Security prior to 2000 | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Virtual Reading Room prior to 2000 Home > About Us > Our Operations > NNSA Office of General Counsel > Freedom of Information Act (FOIA) > Virtual Reading Room prior to 2000 Virtual Reading Room prior to 2000 Printer-friendly version Printer-friendly version

474

Unlocking Customer Value: The Virtual Power Plant | Department of Energy  

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

Unlocking Customer Value: The Virtual Power Plant Unlocking Customer Value: The Virtual Power Plant Unlocking Customer Value: The Virtual Power Plant The utility world has changed drastically in the last 10 years. New technologies like Smart Meters and fully functional Smart Grid concepts have made large inroads into the utility space and no one should want to be left behind. Utilities also face additional pressures from regulatory bodies who are continuing to encourage carbon reduction and greater customer flexibility. Utilities need to balance these new requirements with the financial obligations of providing reliable power (at a reasonable price) while attempting to meet shareholder expectations. Each of these goals are not necessarily complimentary, thus utilities need to determine how to address each one.

475

Los Alamos' New Virtualized Data Center Saves Energy and Cash |  

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

Alamos' New Virtualized Data Center Saves Energy and Cash Alamos' New Virtualized Data Center Saves Energy and Cash Los Alamos' New Virtualized Data Center Saves Energy and Cash March 7, 2011 - 3:15pm Addthis It takes 8,900 kilowatt hours to provide electricity to one U.S. house for a year. With the energy saved annually through Infrastructure on Demand, LANL can power 216 homes. | Photo Courtesy of LANL It takes 8,900 kilowatt hours to provide electricity to one U.S. house for a year. With the energy saved annually through Infrastructure on Demand, LANL can power 216 homes. | Photo Courtesy of LANL Sarah LaMonaca Communications Specialist, Office of Energy Efficiency & Renewable Energy What are the key facts? Data centers are responsible for nearly 2% of U.S. electricity consumption -- a price tag of $4.5 billion.

476

Virtual Library on Genetics from Oak Ridge National Laboratory  

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

The World Wide Web (WWW) Virtual Library is a collaborative effort to provide topic indices that break down into many subtopics guiding users to vast resources of information around the world. ORNL hosts the Virtual Library on Genetics as part of the WWWVL's Biosciences topic area. The VL on Genetics is also a collection of links to information resources that supported the DOE Human Genome Project. That project has now evolved into Genomics: GTL. GTL is DOE's next step in genomics--builds on data and resources from the Human Genome Project, the Microbial Genome Program, and systems biology. GTL will accelerate understanding of dynamic living systems for solutions to DOE mission challenges in energy and the environment. The section of the Virtual Library on Genetics that is titled Organisms guides users to genetic information resources and gene sequences for animals, insects, microbes, and plant life.

477

Virtual Reading Room after to 2000 | National Nuclear Security  

National Nuclear Security Administration (NNSA)

after to 2000 | National Nuclear Security after to 2000 | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog Virtual Reading Room after to 2000 Home > About Us > Our Operations > NNSA Office of General Counsel > Freedom of Information Act (FOIA) > Virtual Reading Room after to 2000 Virtual Reading Room after to 2000 Printer-friendly version Printer-friendly version

478

Turbulence radiation interaction in Reynolds-averaged Navier-Stokes simulations of nonpremixed piloted turbulent laboratory-scale flames  

SciTech Connect (OSTI)

Numerical simulation results are presented for two axisymmetric, nonluminous turbulent piloted jet diffusion flames: Sandia Flame D (SFD) and Delft Flame III (DFIII). Turbulence is represented by a Reynolds stress transport model, while chemistry is modeled by means of steady laminar flamelets. We use the preassumed PDF approach for turbulence-chemistry interaction. A weighted sum of gray gases model is used for the gas radiative properties. The radiative transfer equation is solved using the discrete ordinates method in the conservative finite-volume formulation. The radiative loss leads to a decrease in mean temperature, but does not significantly influence the flow and mixing fields, in terms either of mean values or of rms values of fluctuations. A systematic analysis of turbulence-radiation interaction (TRI) is carried out. By considering five different TRI formulations, and comparing also with a simple optically thin model, individual TRI contributions are isolated and quantified. For both flames, effects are demonstrated of (1) influence of temperature fluctuations on the mean Planck function, (2) temperature and composition fluctuations on the mean absorption coefficient, and (3) correlation between absorption coefficient and Planck function. The strength of the last effect is stronger in DFIII than in SFD, because of stronger turbulence-chemistry interaction and lower mean temperature in DFIII. The impact of the choice of TRI model on the prediction of the temperature-sensitive minor species NO is determined in a postprocessing step with fixed flow and mixing fields. Best agreement for NO is obtained using the most complete representation of TRI. (author)

Habibi, A.; Merci, B. [Department of Flow, Heat and Combustion Mechanics, Ghent University, B-9000 Ghent (Belgium); Roekaerts, D. [Delft University of Technology, Delft (Netherlands)

2007-10-15T23:59:59.000Z

479

Combustion regimes of particle-laden gaseous flames: influences of radiation, molecular transports, kinetic-quenching, stoichiometry  

Science Journals Connector (OSTI)

We study flat flames propagating steadily in a reactive gaseous premixture which is seeded with an inert solid suspension. Our main assumptions are: (i) the two-reactant, one-step overall reaction we choose as the combustion process has a rate which vanishes at and below a prescribed temperature (Tc) and resumes the Arrhenius form at higher temperatures; (ii) both phases are considered as continua and have the same local speed and temperature; (iii) radiation among the particles follows the Eddington approximation specialized to a grey medium and the attenuation length markedly exceeds the conduction - convection length in the gas; (iv) the activation energy is large. The first regimes we consider comprise a thin flame front (dominated by molecular transports, convection and chemistry) embedded in much thicker radiation - convection zones. Jump conditions across the former are derived analytically and then used as targets in a shooting method to analyse the thickest zones and compute the burning speed (U). Such regimes only exist for equivalence ratios () above a load-dependent critical value which corresponds to a turning point of the U() curve. This turning point is due to radiative heat losses from the thin flame front to the cooler adjacent zones, which lead to extinction. Over restricted, well defined ranges of composition other regimes may also exist, which have monotonic temperature profiles culminating slightly above Tc. When they are too thick to be affected by molecular transports and are thus similar to coal-dust -air flames, their structure, domain of existence and speed are investigated analytically and numerically. The corresponding U() curve exhibits an upper limit equivalence ratio * characterized by an end-point, beyond which such regimes cannot exist. The influence of molecular diffusion is then accounted for and shown to modify the results only slightly.

Rodolphe Blouquin; Guy Joulin; Younès Merhari

1997-01-01T23:59:59.000Z

480

Comparative NEXAFS Study on Soot Obtained from an Ethylene/Air Flame, a Diesel Engine, and Graphite  

Science Journals Connector (OSTI)

Comparative NEXAFS Study on Soot Obtained from an Ethylene/Air Flame, a Diesel Engine, and Graphite ... Aerosol and Nanostructures Laboratory, Istituto Motori, CNR, Napoli, Italy, and Department of Chemical and Materials Engineering and Consortium for Fossil Fuel Science, University of Kentucky, Lexington, Kentucky 40515 ... Microstructure and molecular structure properties of different carbonaceous byproducts from combustion are fundamental to evaluate the radiative properties of such materials when combustion aerosols interact with solar radiation in atmosphere. ...

Stefano di Stasio; Artur Braun

2005-11-15T23:59:59.000Z

Note: This page contains sample records for the topic "flame stabilization virtually" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

TIME-VARYING FLAME IONIZATION SENSING APPLIED TO NATURAL GAS AND PROPANE BLENDS IN A PRESSURIZED LEAN PREMIXED (LPM) COMBUSTOR  

SciTech Connect (OSTI)

In-situ monitoring of combustion phenomena is a critical need for optimal operation and control of advanced gas turbine combustion systems. The concept described in this paper is based on naturally occurring flame ionization processes that accompany the combustion of hydrocarbon fuels. Previous work has shown that flame ionization techniques may be applied to detect flashback, lean blowout, and some aspects of thermo-acoustic combustion instabilities. Previous work has focused on application of DC electric fields. By application of time-varying electric fields, significant improvements to sensor capabilities have been observed. These data have been collected in a lean premixed combustion test rig operating at 0.51-0.76 MPa (5-7.5 atm) with air preheated to 588 K (600°F). Five percent of the total fuel flow is injected through the centerbody tip as a diffusion pilot. The fuel composition is varied independently by blending approximately 5% (volume) propane with the pipeline natural gas. The reference velocity through the premixing annulus is kept constant for all conditions at a nominal value of 70 m/s. The fuel-air equivalence ratio is varied independently from 0.46 – 0.58. Relative to the DC field version, the time-varying combustion control and diagnostic sensor (TV-CCADS) shows a significant improvement in the correlation between the measured flame ionization current and local fuel-air equivalence ratio. In testing with different fuel compositions, the triangle wave data show the most distinct change in flame ionization current in response to an increase in propane content. Continued development of this sensor technology will improve the capability to control advanced gas turbine combustion systems, and help address issues associated with variations in fuel supplies.

D. L. Straub; B. T. Chorpening; E. D. Huckaby; J. D. Thornton; W. L. Fincham

2008-06-13T23:59:59.000Z

482

Stability Breakout Session  

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

Breakout Session Breakout Session I Chemical Stability * What are the Reactions? i. Products must be identified (loss of IEC is not enough) ii. Establish reaction mechanism(s) iii. Measure the kinetics II Reaction of membrane with OH - /HCO 3 - /CO 3 2- at various hydration levels - nucleophilicity and basicity of anion species i. Cations a) Small molecule analogues b) Effects of hydration state and temperature c) Cation design R 4 N + ???? Families of cations * Ammoniums * Guanadiniums * Sulfoniums * Phosphoniums [problematic] * Phosphazeniums II Reaction with OH - /HCO 3 - /CO 3 2- and Hydration levels (cont'd) ii. Tethers - Link to cation - Link to backbone - Spacers (in between) iii. Backbone a) Hydrocarbon - Structure - Functional makeup b) Fluoropolymer III Reactive O 2 Species HOO - /H

483

Flame aerosol nano-technology has been developed to preparation of thin and defect-free porous membrane from the gas phase as a one step method in preparation of membrane for gas  

E-Print Network [OSTI]

Abstract Flame aerosol nano-technology has been developed to preparation of thin and defect on deposition of nano particles (-Al2O3, MgO or spinel MgAl2O4), formed in the premixed flame reactor through/or aluminium precursors in the flame to form nano-particles of -Al2O3, MgO or MgAl2O4 spinel. The generated

484

High-Efficiency, Magnetized, Virtual-Cathode Microwave Generator  

Science Journals Connector (OSTI)

Microwave generation by electron beams in virtual-cathode configurations can achieve significant power levels. However, most designs inherently have two competing mechanisms generating microwaves: the oscillating virtual cathode and the reflexing electrons. These mechanisms interfere destructively with each other. This paper reports investigation of a novel idea of using an external axial magnetic field and a thick anode with an appropriate collimating slot to extract the electron beam and to suppress the reflexing electrons. It was found that high-power, narrow-band, monochromatic microwaves could be generated with efficiency of 10% to 20%.

Thomas J. T. Kwan

1986-10-13T23:59:59.000Z

485

An Integrated Approach to Automatic Management of Virtualized Resources in Cloud Environments  

Science Journals Connector (OSTI)

......Integrated Approach to Automatic Management of Virtualized...of Computer Science and Engineering...resource management|cloud computing...Integrated Approach to Automatic Management of Virtualized...of Computer Science and Engineering......

Qiang Li; Qin-fen Hao; Li-min Xiao; Zhou-jun Li

2011-06-01T23:59:59.000Z

486

Comparing Perception of Real and Virtual Architectural Space Using Video Game Technology  

E-Print Network [OSTI]

questions in a virtual and real version of the same building and the results were compared. It was found that in the virtual environment people tended to underestimate and to perceive distance less accurately than in real space. Findings show...

Spross, Matthew

2011-04-25T23:59:59.000Z

487

Students Share Experiences from First Run of BioenergizeME Virtual...  

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

Students Share Experiences from First Run of BioenergizeME Virtual Science Fair Students Share Experiences from First Run of BioenergizeME Virtual Science Fair December 18, 2014 -...

488

Extraction of Contextual Knowledge and Ambiguity Handling for Ontology in Virtual Environment  

E-Print Network [OSTI]

This dissertation investigates the extraction of knowledge from a known environment. Virtual ontology – the extracted knowledge – is defined as a structure of a virtual environment with semantics. While many existing 3D reconstruction approaches can...

Lee, Hyun Soo

2011-10-21T23:59:59.000Z

489

The Study on Building of Virtual Reality System in Large Surface Coal Mine  

Science Journals Connector (OSTI)

The building of virtual reality system for the opencast mine is a complicated and systemic project. The building process of virtual system includes data collection, GIS geodabase, model designing and raster te...

Baoying Ye; Nisha Bao; Zhongke Bai

2011-01-01T23:59:59.000Z

490

Project PEAC : a Personal, Expressive Avatar Controller for the operation of virtual characters  

E-Print Network [OSTI]

The purpose of this thesis was to design and construct a prototype for the control of virtual avatars in a virtual space. It was designed with the intent to feature multiple interfaces such that the user would have many ...

Santos, Kristopher B. dos

2010-01-01T23:59:59.000Z

491

Header for SPIE use The use of collaborative virtual environments in the  

E-Print Network [OSTI]

slices, volume visualization, wind/trajectory vectors, and various image projection formats. Virtual 'real-time' observations collected by autonomous sensors or swimmer scouts. Keywords: Virtual radar (SAR), towed undulating vehicles (SCANFISH or SEASOAR), and autonomous underwater vehicles (AUVs

Johnson, Andrew

492

Scenario Planning as the Development of Leadership Capability and Capacity; and Virtual Human Resource Development  

E-Print Network [OSTI]

with the development of leadership capability and capacity. Findings from the second stream of inquiry into sophisticated virtual environments included formal and informal learning in the 3D virtual world of Second Life (SL). Respondents in the study completed forty...

McWhorter, Rochell 1963-

2011-08-03T23:59:59.000Z

493

Method of virtual trajectories for the design of gravity assisted missions  

Science Journals Connector (OSTI)

A novel method of virtual trajectories is proposed for the design of multiple gravity assist trajectories. The database of virtual trajectories can be tabulated for any planetary sequence and used in subsequen...

M. Yu. Ovchinnikov; S. P. Trofimov; M. G. Shirobokov

2013-11-01T23:59:59.000Z

494

Modeling and Simulation of the Virtualized Scenes Base on the Open Modelica  

Science Journals Connector (OSTI)

Experimental teaching plays a very important role in modern education. For the Distance Education via Computer Networks, this paper gives a system architecture of virtual experiment as the basis of virtual ins...

Jiang YuXiang; Zhou Xiaolong; Li JinPing…

2011-01-01T23:59:59.000Z

495

Stabilized radio-frequency quadrupole  

DOE Patents [OSTI]

A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1982-09-29T23:59:59.000Z

496

QUANTITATIVE STABILITY ANALYSIS OF STOCHASTIC ...  

E-Print Network [OSTI]

? is said to be lower semi-continuous (lsc for short) at ¯x ? X if and only if ..... It is also known as a distance of probability measures having ?-structure, see [45] ...... In order to compare the previous novel stability result for two-stage models ...... Quantitative stability in stochastic programming: The method of probability metrics ...

2013-07-14T23:59:59.000Z

497

Implementing multi-step chemical kinetics models in opposed-flow flame spread over cellulose and a comparison to single-step chemistry  

SciTech Connect (OSTI)

Multi-step, gas-phase chemical kinetics are introduced into flame spread modeling efforts. An unsteady multi-step, gas-phase kinetics model both with and without steady-state species assumptions, and including nonunit Lewis number, is compared with a model including a single, finite-rate gas-phase reaction, which has been the usual approach in flame spread modeling. Laminar diffusion flames over a thin fuel in an opposing O{sub 2}/N{sub 2} flow are considered with the solution in two-dimensional space of momentum, energy, and 12 gas-phase species. Results for the multi-step models show detailed flame structure in terms of species and heat release distributions throughout the flame and the role of chemical kinetics as a controlling mechanism in flame spread. Of particular interest is the potential of multi-step chemical kinetics in solutions at near-extinction limit conditions. While the incorporation of nonunit Le alone affords more detailed species transport, in high opposing flows it was found to give only minor structural differences form the single-step unit Le model. The multi-step chemistry allows for the gas kinetics to be self-adjusting to environmental conditions. As a result, the distribution of endothermicity and exothermicity throughout the flame and for particular reversible reactions is found to be a function of the flow environment, which overcomes a major drawback of single-step models, namely a fixed heat of combustion independent of environmental conditions, or one that must be determined separately from the model itself.

Wolverton, M.K.; Altenkirch, R.A.; Tang, L. [Mississippi State Univ., MS (United States)] [Mississippi State Univ., MS (United States)

1999-07-01T23:59:59.000Z

498

Fluorine-supported flames ignited by a pulsed CO2 laser  

Science Journals Connector (OSTI)

The chemistry accompanying pulsed CO2 laser irradiation of fuel—SF6 mixtures was examined using time-integrated visible emission spectroscopy and analysis of the IR absorption spectra of end products. Under suitable conditions of laser energy, gas pressure, mixture ratio and cell geometry, the visible luminescence exhibits characteristics of fluorine-supported flames. Similar emission has been observed in irradiated fuel—S2F10 mixtures. An analysis of ignition delay versus absorbed laser energy is presented for CH4?SF6 mixtures; it accounts for fluence-dependent absorption by these mixtures and models the effects of hydrodynamic motion on the initial pressure, density and temperature profiles in the samples using a computer code for two-dimensional wave propagation. Many of the IR absorption data are consistent with a reaction mechanism involving the formation of small hydrocarbon intermediates followed by efficient hydrogen abstraction to generate end products such as CS2, CF4 and C2F4. Mechanisms for reaction initiation are discussed.

Wayne M. Trott

1984-01-01T23:59:59.000Z

499

Virtual Money Systems: a Phenomenal Analysis Jingzhi Guo and Angelina Chow  

E-Print Network [OSTI]

Virtual Money Systems: a Phenomenal Analysis Jingzhi Guo and Angelina Chow Department of Computer of virtual money is observed and presented high importance to both e-commerce and e-society fields. This paper, as a pioneer research, has attempted to make a phenomenal analysis on the existing virtual money

Guo, Jingzhi

500

Towards the Use of Collaborative Virtual Environments to Crew Unmanned Oil Platforms  

E-Print Network [OSTI]

462 Towards the Use of Collaborative Virtual Environments to Crew Unmanned Oil Platforms Hugo Fuks, Oil & Gas. 1. Introduction The use of Computer Graphics and Virtual Reality has revolutionised several the task. We instantiate our vision appointing the results of some initial experiments using Virtual

Barbosa, Alberto