| Flammability and Explosion Limits of H2 and H2/CO: A Literature Review |
10 SEP 92 |
26 pages |
| Authors:
Norman Cohen; AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS
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 | The literature related to the flammability and explosion limits of H2/O2,H2/O2/diluent, CO/H2/O2, and CO/H2/air mixtures is reviewed, with particular attention to those aspects relevant to space- and launch vehicle- related conditions. The discussion is hardly exhaustive but is meant to be reasonably self-contained. Applications to a recent Atlas II AC-101 booster system exhaust leak are considered. |
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| Survey of Space Environment Services Center Users and Services |
MAY 92 |
10 pages |
| Authors:
Larry Combs; Thomas Niichel; Norman Cohen; AIR FORCE SATELLITE CONTROL FACILITY SUNNYVALE AFS CA
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| The Space Environment Services Center (SESC) provides various products and services in support of users of solar-terrestrial information. In the past, representation by users of solar-terrestrial and predictions services has been regrettably low at the Solar Terrestrial Predictions (STP) Workshops. For users of solar-terrestrial information, and especially those who would be unable to attend the workshop, a survey was designed to help present their views. The survey presents a statistical ... |
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| NF3 Combustor for Cylindrical Laser. |
17 MAR 1987 |
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| Authors:
Walter R. Warren Jr.; Norman Cohen; DEPARTMENT OF THE AIR FORCE WASHINGTON DC
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 | A combustor using Deuterium Nitrogen Trifluoride/Helium is used in a laser gain generator in a cylindrical gas laser. The combustor includes a plurality of primary rings having fuel, oxidizer and diluent orifices therein. Fuel and oxidizer orifices form a triplet injector set that provides a reactant set. Two diluent orifices form a diluent injector set that provides a diluent set. These sets alternate about each primary ring and from one ... |
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| Review of Rate Data for Reactions of Interest in HF and DF Lasers |
25 OCT 1982 |
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| Authors:
Norman Cohen; Jerry F. Bott; AEROSPACE CORP EL SEGUNDO CA
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| Chemical reactions and energy transfer processes of importance in H2- F2 and D2-F2 chemical lasers are reviewed and the current state of knowledge is evaluated. Best current estimates for these processes are given and the uncertainties assessed. (Author) |
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| Rate Enhancement Resulting from Reagent Vibrational Excitation as Estimated by the BEBO Method |
01 SEP 1981 |
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| Authors:
Norman Cohen; Stanley W. Mayer; AEROSPACE CORP EL SEGUNDO CA AEROPHYSICS LAB
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| The bond-energy bond-order (BEBO) method for calculating rate coefficients and activation energies on the basis of molecular properties has been applied to estimating rate coefficients and activation energies for H- transfer reactions involving vibrationally excited reactants. The reactions examined included Br + H2(v equals 0, 1) equals H + HBr, Br + HC1(v equals 0, 1, 2) equals C1 + HBr, and F + HC1(v equals 0, 1) equals C1 ... |
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| Rate Coefficients Calculated by the Bond-Energy Bond-Order Method for Excited State F + H2 in equilibrium with H + HF Reactions. |
16 FEB 1979 |
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| Authors:
Stanley W. Mayer; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF IVAN A GETTING LABS
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| Because of the importance of rate coefficients in determining the power output of HF and DF chemical lasers, the bond-energy bond-order (BEBO) method for predicting rate coefficients is applied herein to the excited-state reactions H2(y kcal) + F in equilibrium with H + HF(v = 0,1,2,3,...) and D2(y kcal) + F in equilibrium with D + DF(v = 0,1,2,3,...) where the value of y is 0,1,2,4,8,..., kcal of excitation. Inversions ... |
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| A Review of Rate Coefficients in the H2-F2 Chemical Laser System - Supplement (1977). |
08 JUN 1978 |
40 pages |
| Authors:
Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF AEROPHYSICS LAB
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| This report reviews the literature published since the last report covering this subject appeared: 'A Review of Rate Coefficients in the H2-F2 Chemical Laser System,' N. Cohen and J. F. Bott. Published rate data are summarized and evaluated; a list of 'best' estimates of rate coefficients is presented. |
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| A Review of Rate Coefficients in the D2-F2 Chemical Laser System. |
05 AUG 1977 |
54 pages |
| Authors:
Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF AEROPHYSICS LAB
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| The literature pertaining to the chemical kinetics of the deuterium-fluorine chemical laser system is critically reviewed and data are evaluated. A set of best values of all rate coefficient is recommended for modeling and computer calculations. Where experimental data are lacking, estimates are made on the basis of current theoretical techniques or data for analogous kinetic processes. (Author) |
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| Collisional Quenching and Radiative Decay Studies of NF(a1 delta) and NF(b1 Sigma plus). |
15 APR 1977 |
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| Authors:
Munson A. Kwok; John M. Herbelin; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF AEROPHYSICS LAB
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| From these preliminary studies, it was concluded that this system is a chemical electronic laser candidate. Some of the crucial rate coefficients needed for evaluating the system quantitatively and for constructing a model must be measured to assess further this possibility. Among the rate coefficients reported here are that for Reaction and those for the quenching of NF by H and H2. The radiative decay rate for NF is estimated. ... |
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| A Review of Rate Coefficients in the H2-F2 Chemical Laser System. |
15 APR 1976 |
106 pages |
| Authors:
Norman Cohen; Jerry F. Bott; AEROSPACE CORP EL SEGUNDO CALIF AEROPHYSICS LAB
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| In recent years, considerable effort has been expended at The Aerospace Corporation Aerophysics Laboratory to design theoretical models for computer calculations of the bahavior and performance of HF chemical lasers, both pulsed and continuous. In order to perform such calculations, the rate coefficients of the various chemical reactions and energy transfer processes that occur must be known, or at least estimated. To this end, the Chemical Kinetics Department has attempted ... |
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| A Review of Rate Coefficients in the H2-Cl2 Chemical Laser System. |
19 MAR 1975 |
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| Authors:
Norman Cohen; Jerry F. Bott; AEROSPACE CORP EL SEGUNDO CALIF
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| The chemical and energy transfer reactions involved in the H2-Cl2 chemical laser system are discussed. Current experimental and theoretical evidence relevant to a selection of the most probable values of rate coefficients is reviewed, and a set of best values is recommended. Dissociation-recombination, metathesis, and energy transfer reactions are covered. |
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| Flow Tube Studies of the Deactivation of HF(V) by Selected Polyatomic Molecules. |
27 FEB 1975 |
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| Authors:
Munson A. Kwok; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF
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| A large-diameter, medium-pressure flow tube has been used to study deactivation processes by selected polyatomic molecules that are potentially relevant in chemical laser systems. Effective vibrational deactivation rate constants for HF(v = 1,2,3) relaxed by H2S, CO2, N2O, CH4, CF4, and SF6 have been determined. The rates for a given chaperone increase with increasing v. The agreement with results for HF(1) + M reported from laser-induced fluorescence experiments is generally ... |
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| Vibrational Relaxation of Hcl(v = 1) in the Presence of Several Diatomic Molecules at 295 to 750K. |
21 FEB 1975 |
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| Authors:
Jerry F. Bott; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF
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| The relaxation rates of HCl(v = 1) by HF, HBr, H2, D2, N2, and Cl2 have been measured at 295 to 700K in shock tube laser-induced fluorescence experiments. |
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| A Brief Review of Rate Coefficients for Reactions in the D2-F2 Chemical System. |
15 JAN 1974 |
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| Authors:
Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| The chemical and energy transfer reaction involved in the deuterium-fluoride chemical laser system is discussed. Current experimental and theoretical evidence relevant to a selection of the most probable value of rate coefficients is reviewed, and a set of best values is recommended. (Author) |
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| Temperature Dependence of V-V and V-R, T Energy Transfer Measurements in Mixtures Containing HF. |
31 AUG 1973 |
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| Authors:
Jerry F. Bott; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| A pulsed HF chemical laser has been used to excite HF molecules to their first vibrational level. The decay times of the infrared fluorescence from HF(v=1) have been used to determine the rate coefficients for energy transfer from HF to various collision partners including H2, D2, N2, O2, DF, HCl, CO2, NO, CO, and HBr. The experiments were performed at temperatures from 450 to 1000K for most of the molecules, ... |
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| Vibrational Relaxation Measurements by a Combined Shock Tube-Laser Induced Fluorescence Technique. |
25 AUG 1973 |
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| Authors:
Jerry F. Bott; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| Vibrational relaxation measurements in HF and DF have been obtained at intermediate temperatures by combining the laser-induced fluorescence technique with shock compression heating in a shock tube. The combination of the two techniques has several advantages: it permits measurements over a wide range of temperatures, and eliminates problems of wall reactions and leaky cells at high temperatures. This method was used to obtain HF and DF vibrational relaxation data in ... |
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| The Chemical Production of Electronically Excited States in the H/NF2 System, |
25 JUL 1973 |
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| Authors:
John M. Herbelin; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| A mixture of NF3 and Ar is passed through an rf discharge in a flow system to produce, among other species, F and NF2. When H2, D2, or CH4 is added downstream, reaction with F atoms produces vibrationally excited HF or DF and H, D, or CH3. The latter free radicals can react with NF2, probably by an elimination reaction, to produce electronically excited NF. A vibrational-to-electronic energy transfer process ... |
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| Temperature Dependence of Several Vibrational Relaxation Processes in DF-CO2 Mixtures. |
22 JUN 1973 |
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| Authors:
Jerry F. Bott; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| A pulsed DF chemical laser has been used to excite DF molecules to their first vibrational level. Decay of the infrared DF fluorescence was used to calculate the vibrational relaxation times of DF due to collisions with itself at temperatures between 468 and 920K as well as at room temperature. The high temperature data were obtained in a laser-induced fluorescence experiment performed behind a reflected shock wave in a shock ... |
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| A Kinetic Model and Computer Simulation for a Pulsed DF-CO2 Chemical Transfer Laser. |
01 JUN 1973 |
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| Authors:
Ronald L. Kerber; Norman Cohen; George Emanuel; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| The chemical and energy transfer reactions involved in the helium-diluted DF-CO2 chemical transfer laser system are discussed. Experimental and theoretical rate coefficient literature is reviewed, and the most probable rates are selected for the kinetic model of the reaction system. Results of computer experiments show the relative importance of these reactions for pulsed laser simulation. Predicted laser performance is most sensitive to values of rate coefficients for DF-CO2 transfer, collisional ... |
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| Theoretical Performance of an HCl Chemical Continuous-Wave Laser. |
15 MAR 1973 |
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| Authors:
George Emanuel; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| A quantitative analysis is presented of an H2 + Cl2 cw chemical laser, including the influence of stimulated emission on the reacting medium. Numerically determined solutions encompass one-dimensional fluid mechanics, chemical kinetics, radiative de-excitation, and their mutual interaction. The excited HCl(v) is produced by chain reaction, with only the H + Cl2 reaction providing v = or > 1. Because of the large amount of HCl(0) produced by the Cl ... |
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| A Shock Tube Study of DF Vibrational Relaxation. |
01 FEB 1973 |
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| Authors:
Jerry F. Bott; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| The vibrational relaxation of DF behind incident shock waves in the temperature range 800 to 4000K was studied by monitoring the 3.5-micro m infrared emission. Relaxation times reduced to standard pressure were obtained for mixtures containing 1 to 10% DF in Ar and for mixtures containing N2, H2, and F atoms. These data were used for calculation of the relaxation times of DF due to these various gases. The deactivation ... |
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| Further Studies on the Dissociation of HBr Behind Shock Waves. |
30 NOV 1972 |
44 pages |
| Authors:
Norman Cohen; Robert R. Giedt; Theodore A. Jacobs; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| Previously reported shock tube studies of the dissociation of HBr in the temperature range of 2100-4200K have been extended to lower temperatures (1450-2300K) in pure HBr. The results imply that, in the lower range of temperatures, the activation energy of dissociation can be approximated by the HBr bond energy (88 kcal/mole). It was also found that, in this temperature range, the rate of HBr dissociation is sensitive to the Br ... |
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| A Review of Rate Coefficients for Reactions in the H2-F2 Laser System, |
01 NOV 1972 |
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| Authors:
Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| The chemical and energy transfer reactions involved in the hydrogen fluoride chemical laser system are discussed. Current experimental and theoretical evidence relevant to a selection of the most probable values of rate coefficients is reviewed, and a set of best values is recommended. (Author) |
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| Vibrational Relaxation of HF in the Presence of H2. |
15 AUG 1972 |
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| Authors:
Jerry F. Bott; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| The vibrational relaxation of HF has been studied in the presence of H2 behind incident shock waves in the temperature range 1350 to 4000K by monitoring the 2.7 micrometer infrared emission. Under the conditions of these experiments, the HF-H2 system cannot be readily treated analytically. Therefore, the experimental profiles of the concentration of the relaxing species are matched with computer-calculated profiles. Reasonable matches between experimental and computer profiles are obtained ... |
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| Theoretical Performance of an HF Chemical CW Laser. |
15 FEB 1972 |
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| Authors:
George Emanuel; Norman Cohen; Theodore A. Jacobs; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| A quantitative analysis of an HF cw chemical laser is presented that includes the influence of stimulated emission on the reacting medium. The numerically determined solutions encompass one-dimensional fluid mechanics, chemical kinetics, radiative de-excitation, and their mutual interaction. A comprehensive parametric study examines the effects due to changed plenum conditions, mixture ratios, and cavity parameters. Detailed discussions are presented of (1) vibration-vibration and vibration-translation energy exchange, (2) chemical efficiency, (3) ... |
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| Shock Tube Studies of HF Vibrational Relaxation. |
09 SEP 1971 |
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| Authors:
Jerry F. Bott; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| The vibrational relaxation of HF has been studied behind incident shock waves in the temperature range 1350 to 4000K by monitoring the 2.7 millimicrons infrared emission. Relaxation times reduced to standard pressure were obtained for mixtures containing 1% to 10% HF in argon and for mixtures containing N2, He, and D2. These data were used to calculate the relaxation times of HF due to these various gases. The relaxation rate ... |
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| A Review of Rate Coefficients for Reactions in the H2-F2 Laser System. |
03 SEP 1971 |
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| Authors:
Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| The chemical and energy transfer reactions involved in the hydrogen fluoride chemical laser system are discussed. Current experimental and theoretical evidence relevant to a selection of the most probable values of rate coefficients is reviewed, and a set of 'best' values is recommended. (Author) |
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| CHEMICAL KINETICS OF HYDROGEN HALIDE LASERS. VOLUME I: THE H2-C2 SYSTEM. |
30 JUL 1969 |
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| Authors:
Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| A detailed kinetic model of the HCl chemical laser produced by the flash photolytically initiated H2--Cl2 explosion is described, and the results of computer calculations on such a system are discussed. It is shown that currently accepted values of the various rate constants, supplemented in a few cases by reasonable estimates of previously unmeasured rate constants, are adequate to approximate the observed laser behavior of this system. It ... |
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| TEMPERATURE DEPENDENCE OF CHEMILUMINESCENT REACTIONS. VOLUME III: THE SULFUR DIOXIDE AFTERGLOW. |
OCT 1968 |
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| Authors:
Norman Cohen; Rolf W. F. Gross; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| The object of the glow discharge shock tube is to be able to fire a mild shock into a flowing gas that has been passed through an electrical discharge. The shock heats and compresses the gas rapidly, but not to such a high temperature that further dissociation takes place. This technique was applied to the O + SO afterglow. The SO2 afterglow continuum was produced by two independent methods: (a) ... |
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| KINETICS OF HYDROGEN HALIDES IN SHOCK WAVES. THE REACTIONS CL + HCL AND CL + CL2. |
JAN 1968 |
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| Authors:
Theodore A. Jacobs; Robert R. Giedt; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| The decomposition of HCl via the chlorine exchange reaction Cl + HCl = Cl2 + H was studied in the shock tube. The rate constant deduced for this reaction over the temperature range 3500 - 5200K was found to be consistent with the low temperature value of Klein and Wolfsberg. The study also yielded the efficiency of Cl atoms in decomposing Cl2. Compared to Ar, Cl was found to be ... |
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| TEMPERATURE DEPENDENCE OF CHEMILUMINESCENT REACTIONS. VOLUME II. THE NITRIC OXIDE AFTERGLOW. |
NOV 1967 |
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| Authors:
Rolf W. F. Gross; Norman Cohen; AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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| Using a glow discharge shock tube, measurements were made of the temperature and density dependence of the beta, gamma, and delta bands for the NO recombination afterglow. The absolute rate constants were determined for each of the vibrational transitions of the three bands at room temperature. Results for the total band intensities are given. |
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Reports by Author
