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An active particle diffusion theory of flame quenching for laminar flames

Description: An equation for quenching distance based on the destruction of chain carriers by the surface is derived. The equation expresses the quenching distance in terms of the diffusion coefficients and partial pressures of the chain carriers and gas phase molecules, the efficiency of the surface as a chain breaker, the total pressure of the mixture, and a constant which depends on the geometry of the quenching surface. Quenching distances measured by flashback for propane-air flames are shown to be con… more
Date: March 4, 1952
Creator: Simon, Dorothy M. & Belles, Frank E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A relation between burning velocity and quenching distance

Description: A thermal quenching equation and the Semenov burning velocity equation were combined to give expressions for the product and quotient of burning velocity and quenching distance. Experimental results for hydrocarbon-oxygen-inert gas, hydrocarbon-nitrous oxide, hydrogen-air, hydrogen-bromine, and the ethylene oxide decomposition flames were fairly well correlated by the product equation.
Date: November 1956
Creator: Potter, A. E., Jr. & Berlad, A. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effect of channel geometry on the quenching of laminar flames

Description: Report presenting the effect of channel geometry on flame quenching, as calculated on the basis of average active particle chain lengths, is related among six different geometries: plane parallel plates of infinite extent, cylindrical tubes, rectangular slots, cylindrical annuli, and tubes of elliptical and equilaterally triangular shape. The results indicated that the observed variation of flame quenching as a function of quenching geometry may be successfully predicted for a range of pressure… more
Date: May 6, 1954
Creator: Berlad, A. L. & Potter, A. E., Jr.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Zeaxanthin Radical Cation Formation in Minor Light-Harvesting Complexes of Higher Plant Antenna

Description: Previous work on intact thylakoid membranes showed that transient formation of a zeaxanthin radical cation was correlated with regulation of photosynthetic light-harvesting via energy-dependent quenching. A molecular mechanism for such quenching was proposed to involve charge transfer within a chlorophyll-zeaxanthin heterodimer. Using near infrared (880-1100 nm) transient absorption spectroscopy, we demonstrate that carotenoid (mainly zeaxanthin) radical cation generation occurs solely in isola… more
Date: January 31, 2008
Creator: Avenson, Thomas H.; Ahn, Tae Kyu; Zigmantas, Donatas; Niyogi, Krishna K.; Li, Zhirong; Ballottari, Matteo et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Flame Quenching by a Variable-Width Rectangular-Slot Burner as a Function of Pressure for Various Propane-Oxygen-Nitrogen Mixtures

Description: "Flame quenching by a variable-width rectangular-slot burner as a function of pressure for various propane-oxygen-nitrogen mixtures was investigated. It was found that for cold gas temperatures of 27 degrees C, pressures of 0.1 or 1.0 atmosphere, and volumetric oxygen reactions of the oxidant of 0.17, 0.21, 0.30, 0.50, and 0.70, the relation between pressure p and quenching distance d is approximately given by d (unity) p (superscript -r) with r = 1, for equivalence ratios approximately equal t… more
Date: January 28, 1954
Creator: Berlad, Abraham L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Forced convective post CHF heat transfer and quenching. [PWR]

Description: This paper discusses mechanisms in the post-CHF region which provide understanding and qualitative prediction capability for several current forced convective heat transfer problems. In the area of nuclear reactor safety, the mechanisms are important in the prediction of fuel rod quenches for the reflood phase, blowdown phase, and possibly some operational transients with dryout. Results using the mechanisms to investigate forced convective quenching are presented. Data reduction of quenching e… more
Date: January 1, 1980
Creator: Nelson, R.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Quench Protection and Magnet Supply Requirements for the MICE Focusing and Coupling Magnets

Description: This report discusses the quench protection and power supply requirements of the MICE superconducting magnets. A section of the report discusses the quench process and how to calculate the peak voltages and hotspot temperature that result from a magnet quench. A section of the report discusses conventional quench protection methods. Thermal quench back from the magnet mandrel is also discussed. Selected quench protection methods that result in safe quenching of the MICE focusing and coupling ma… more
Date: June 8, 2005
Creator: Green, Michael A. & Witte, Holger
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Secondary defects in quenched platinum

Description: The structure of secondary defects in two different platinum purities quenched under ultra high vacuum, has been studied by transmission electron microscopy. Faulted loops on (100) planes have been observed in both materials. In the less pure platinum, Pt B (but purer in terms of carbon content), the defects were observed after quenching, whereas in the purest one, Pt A (but less pure in terms of carbon content), the defects were formed after a long annealing. The Burgers vector of the loops fo… more
Date: November 1, 1979
Creator: Perez, M.I.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Development of UV-LED Phosphor Coatings for High Efficiency Solid State Lighting

Description: The University of Georgia, in collaboration with GE Global Research, is investigating the relevant quenching mechanism of phosphor coatings used in white light devices based on UV LEDs in a focused eighteen month program. The final goal is the design of high-efficacy white UV-LEDs through improved and optimized phosphor coatings. At the end of the first year, we have reached a fundamental understanding of quenching processes in UV-LED phosphors and have observed severe quenching in standard dev… more
Date: January 1, 2005
Creator: Happek, U.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Jet and Leading Hadron Production in High-energy Heavy-ionCollisions

Description: Jet tomography has become a powerful tool for the study ofproperties of dense matter in high-energy heavy-ion collisions. I willdiscuss recent progresses in the phenomenological study of jet quenching,including momentum, colliding energy and nuclear size dependence ofsingle hadron suppression, modification of dihadron correlations and thesoft hadron distribution associatedwith a quenched jet.
Date: November 1, 2005
Creator: Wang, Xin-Nian
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Inductive Coupling of the Magnets in MICE and its Effect on Quench Protection

Description: The inductive coupling between various MICE magnet circuits is described. The consequences of this coupling on magnet charging and quenching are discussed. Magnet quench protection is achieved through the use of quench-back. Calculations of the quenching of a magnet due to quench-back resulting from circulating currents induced in the magnet mandrel due to quenching of an adjacent magnet are discussed. This report describes how the MICE magnet channel will react when magnets in that channel are… more
Date: September 8, 2005
Creator: Green, Michael A. & Witte, Holger
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Singlet Quenching of Tetraphenylporphyrin and its Metal Derivatives by Iron(III) Coordination Compounds

Description: This article reports on the singlet quenching of 5, 10, 15, 20-tetraphenylporphyrin (H₂TPP) and its magnesium(II) and zinc(II) derivatives (MgTPP and ZnTPP) by a series of iron(III) coordination compounds bearing different ligand systems.
Date: January 6, 1990
Creator: D'Souza, Francis & Krishnan, V.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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Frontier orbital symmetry control of intermolecular electron transfer

Description: Research continued on the study of intermolecular electron transfer. This report discusses the following topics: fluorescence quenching by electron transfer and the modification of quenching dynamics by solvent properties and net free energy change; transient absorption measurements following selective excitation of 1:1 EDA complex isomers; selective quenching of dual fluorescence from linked EDA systems; electron-transfer sensitized cycloreversion of rubrene endoperoxide; and vibronic modifica… more
Date: November 1, 1990
Creator: Stevens, B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Angular Dependence of Jet Quenching Indicates Its Strong Enhancement Near the QCD Phase Transition

Description: We study dependence of jet quenching on matter density, using 'tomography' of the fireball provided by RHIC data on azimuthal anisotropy v{sub 2} of high p{sub t} hadron yield at different centralities. Slicing the fireball into shells with constant (entropy) density, we derive a 'layer-wise geometrical limit' v{sub 2}{sup max} which is indeed above the data v{sub 2} < v{sub x}{sup max}. Interestingly, the limit is reached only if quenching is dominated by shells with the entropy density exa… more
Date: October 22, 2008
Creator: Liao, Jinfeng & Shuryak, Edward
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A comparison of one and two dimensional flame quenching: Heat transfer results

Description: A theoretical investigation of laminar premixed flame quenching is carried out. Two orientations in which a flame may contact a cold wall are compared and contrasted by solving the conservation equations of mass, energy, and species utilizing a finite difference methodology. A one-step mechanism is used to specify the reaction rates. A simple analytical model, which is in qualitative agreement with the numerical results, is also presented. The results show that the heat transfer histories for o… more
Date: March 1, 1993
Creator: Ezekoye, O. A. & Greif, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Combustion Research Program: Flame studies, laser diagnostics, and chemical kinetics. Progress report, 15 July 1987--3 December 1990

Description: We have made a detailed study of the care that must be taken to correctly measure OH radical concentrations in flames. A large part of these studies has concerned collisional quenching of hydride radical species (OH, NH, and NH{sub 2}), in particular the dependence upon rotational level and collision velocity (temperature). The results on OH and NH have shown unique and interesting behavior from the viewpoint of fundamental molecular dynamics, pointing to quenching often governed by collisions … more
Date: January 22, 1991
Creator: Crosley, D. R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Energy dependence of jet transport parameter and parton saturationin quark-gluon plasma

Description: We study the evolution and saturation of the gluondistribution function in the quark-gluon plasma as probed by apropagating parton and its effect on the computation of jet quenching ortransport parameter $\hat q $. For thermal partons, the saturation scale$Q2_s$ is found to be proportional to the Debye screening mass $\mu_D2$.For hard probes, evolution at small $x=Q2_s/6ET$ leads to jet energydependence of hat q. We study this dependence for both a conformal gaugetheory in weak and strong coupl… more
Date: June 24, 2007
Creator: Casalderrey-Solana, Jorge & Wang, Xin-Nian
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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ARCHITECTURE OF A CHARGE-TRANSFER STATE REGULATING LIGHT HARVESTING IN A PLANT ANTENNA PROTEIN

Description: Energy-dependent quenching of excess absorbed light energy (qE) is a vital mechanism for regulating photosynthetic light harvesting in higher plants. All of the physiological characteristics of qE have been positively correlated with charge-transfer between coupled chlorophyll and zeaxanthin molecules in the light-harvesting antenna of photosystem II (PSII). In this work, we present evidence for charge-transfer quenching in all three of the individual minor antenna complexes of PSII (CP29, CP26… more
Date: April 2, 2008
Creator: Fleming, Graham; Ahn, Tae Kyu; Avenson, Thomas J.; Ballottari, Matteo; Cheng, Yuan-Chung; Niyogi, Krishna K. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Microstructure and properties of dual-phase steels containing fine precipitates

Description: Very fine particles (carbides or carbonitrides) of the order of 20 A were extensively examined in the ferrite regions of dual-phase steels subjected to intercritical annealing followed by fast quenching to room temperature. These particles are probably formed during quenching after intercritical annealing. The driving force for the precipitation reaction may arise from the supersaturation of carbon (or nitrogen) in the ferrite phase. These precipitates in certain alloy compositions cause a devi… more
Date: July 1, 1981
Creator: Gau, J.S.; Koo, J.Y.; Nakagawa, A. & Thomas, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Quenching of Einstein-coefficients by photons

Description: Experimental evidence is presented for the change of Einstein's A- coefficients for spontaneous transitions from the upper laser level of argon ion laser discharge due to the presence of the high- intensity laser flux. To demonstrate that this quenching effect cannot be attributed to a reduction in self-absorption of the strong spontaneous emission line, absorption and line profile measurements have been performed. Computer modelling of the reduction of self absorption due to Rabi splitting als… more
Date: March 1, 1991
Creator: Aumayr, F. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Physik); Lee, W.; Skinner, C. H. & Suckewer, S. (Princeton Univ., NJ (USA). Plasma Physics Lab.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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