277 research outputs found
Experimental investigation of the intermediates of isooctane during ignition
Direct measurements of intermediates of ignition are challenging experimental objectives, yet such measurements are critical for understanding fuel decomposition and oxidation pathways. In the current work, a new gas-sampling system is used to provide quantitative discrete measurements of 30 hydrocarbon and oxygenate species during rapid compression facility studies of isooctane ignition. Two target conditions and equivalence ratios (based on molar fuel to oxygen ratio) were studied (P = 5.2 atm, T = 1000 K, φ = 0.4 and P = 4.8 atm, T = 975 K, φ = 1.2). The results are compared with model predictions that use the detailed reaction mechanism developed by Curran et al. ( Combust Flame 2002, 129, 253–280). In general, the model predictions are in excellent agreement with the experimental data, including several trace species. Isobutene (i-C 4 H 8 ) and propene (C 3 H 6 ) were the major olefin species identified in the experiments. The results are consistent with an intermediate temperature reaction path sequence, where isooctane is consumed by H-atom abstraction to yield isooctyl radicals that undergo Β-scission to form olefin and alkyl radical species. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 498–517, 2007Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56133/1/20254_ftp.pd
KCDC - The KASCADE Cosmic-ray Data Centre
KCDC, the KASCADE Cosmic-ray Data Centre, is a web portal, where data of
astroparticle physics experiments will be made available for the interested
public. The KASCADE experiment, financed by public money, was a large-area
detector for the measurement of high-energy cosmic rays via the detection of
air showers. KASCADE and its extension KASCADE-Grande stopped finally the
active data acquisition of all its components including the radio EAS
experiment LOPES end of 2012 after more than 20 years of data taking. In a
first release, with KCDC we provide to the public the measured and
reconstructed parameters of more than 160 million air showers. In addition,
KCDC provides the conceptional design, how the data can be treated and
processed so that they are also usable outside the community of experts in the
research field. Detailed educational examples make a use also possible for
high-school students and early stage researchers.Comment: 8 pages, accepted proceeding of the ECRS-symposium, Kiel, 201
First Experimental Characterization of Microwave Emission from Cosmic Ray Air Showers
We report the first direct measurement of the overall characteristics of
microwave radio emission from extensive air showers. Using a trigger provided
by the KASCADE-Grande air shower array, the signals of the microwave antennas
of the CROME (Cosmic-Ray Observation via Microwave Emission) experiment have
been read out and searched for signatures of radio emission by high-energy air
showers in the GHz frequency range. Microwave signals have been detected for
more than 30 showers with energies above 3*10^16 eV. The observations presented
in this Letter are consistent with a mainly forward-directed and polarised
emission process in the GHz frequency range. The measurements show that
microwave radiation offers a new means of studying air showers at energies
above 10^17 eV.Comment: Accepted for publication in PR
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