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Results for “BROMINE”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

First spectra of chlorine, bromine, and iodine in the 1.8- to 4.0-micron region.

Use of liquid-nitrogen-cooled lead sulfide detectors to extend observations of the first spectra of the halogens in the infrared region as far as 4.0 microns. Descriptions, comprising wavelengths, wave numbers, intensities, and classifications, are presented that serve to close the gap between the upper wavelength limit of the detailed published analyses of these spectra at about 2.5 microns and the groups of recently classified lines near 4 microns, and also to report newly observed lines in the 1.8- to 2.5-micron region made accessible by detectors of improved response characteristics. Listed wavelengths of observed and identified lines are calculated from established values of the energy levels. The descriptions should facilitate the identification of halogen lines in mixed spectra excited in electrodeless tubes containing halogen compounds.

Humphreys, C. J.↗
NASA NTRS1979

Pressure and temperature dependence kinetics study of the NO + BrO yielding NO2 + Br reaction - Implications for stratospheric bromine photochemistry

The reactivity of NO with BrO radicals over a wide range of pressure (100-700 torr) and temperature (224-398 K) is investigated using the flash photolysis-ultraviolet absorption technique. The flash photolysis system consists of a high-pressure xenon arc light source, a reaction cell/gas filter/flash lamp combination, and a 216.5 half-meter monochromator/polychromator/spectrography for wavelength selectivity. The details of the reaction and its corresponding Arrhenius expression are identified. The results are compared with previous measurements, and atmospheric implications of the reaction are discussed. The NO + BrO yielding NO2 + Br reaction is shown to be important in controlling the concentration ratios of BrO/Br and BrO/HBr in the stratosphere, but this reaction does not affect the catalytic efficiency of BrOx in ozone destruction.

Watson, R. T.↗
NASA NTRS1985

Toughening reinforced epoxy composites with brominated polymeric additives

Cured polyfunctional epoxy resins including tris (hydroxyphenyl) methane triglycidyl ether are toughened by addition of polybrominated polymeric additives having an EE below 1500 to the pre-cure composition. Carboxy terminated butadiene acrylonitrile rubber is optionally present in the precure mixture as such or as a pre-formed copolymer with other reactants. Reinforced composites, particularly carbon reinforced composites, of these resins are disclosed and shown to have improved toughness.

Nir, Z.↗
NASA NTRS1985

Toughening reinforced epoxy composites with brominated polymeric additives

Cured polyfunctional epoxy resins including tris(hydroxyphenyl)methane triglycidyl ether are toughened by addition of polybrominated polymeric additives having an EE below 1500 to the pre-cure composition. Carboxy-terminated butadiene-acrylonitrile rubber is optionally present in the pre-cure mixture as such or as a pre-formed copolymer with other reactants. Reinforced composites, particularly carbon-reinforced composites, of these resins are disclosed and shown to have improved toughness.

Nir, Z.↗
NASA NTRS1986

Reductions of Antarctic ozone due to synergistic interactions of chlorine and bromine

The vertical column density of ozone observed in October over Antarctica has fallen precipitously over the past 10 yr. The concentration at Halley Bay (76 deg S, 27 deg W), expressed conventionally in Dobson units (DU), has dropped from about 300 DU in 1975 to less than 200 DU in 1984. Values in 1985 were even lower, comparable with the lowest values recorded anywhere on earth. It is suggested here that the loss of O3 in Antarctica may be attributed to catalysis of O3 recombination by a scheme in which the rate-limiting step is defined by the reaction of ClO + BrO - Cl + Br + O2. Concentrations of NO2 must be low and heterogeneous reactions involving particles in the polar stratospheric clouds must be an important element of the relevant chemistry. Industrial sources make important contributions to the contemporary budgets of both BrO and ClO and are likely to grow significantly in the future.

Mcelroy, M. B.↗