Articles you may be interested inRadical-neutral chemical reactions studied at low temperature with VUV synchrotron photoionization mass spectrometry AIP Conf. Proc. 1501, 1365 (2012); 10.1063/1.4769699 Synchrotron photoionization mass spectrometry study of intermediates in fuel-rich 1,2-dimethoxyethane flame Direct identification of propargyl radical in combustion flames by vacuum ultraviolet photoionization mass spectrometry J. Chem. Phys. 124, 074302 (2006); 10.1063/1.2168448 Photoionization mass spectrometer for studies of flame chemistry with a synchrotron light source Rev. Sci. Instrum. 76, 094102 (2005); 10.1063/1.2010307Photoionization efficiency spectrum and ionization energy of HSO studied by discharge flow-photoionization mass spectrometryWe report the first use of synchrotron radiation, continuously tunable from 8 to 15 eV, for flame-sampling photoionization mass spectrometry ͑PIMS͒. Synchrotron radiation offers important advantages over the use of pulsed vacuum ultraviolet lasers for PIMS; these include superior signal-to-noise, soft ionization, and access to photon energies outside the limited tuning ranges of current VUV laser sources. Near-threshold photoionization efficiency measurements were used to determine the absolute concentrations of the allene and propyne isomers of C 3 H 4 in low-pressure laminar ethylene-oxygen and benzene-oxygen flames. Similar measurements of the isomeric composition of C 2 H 4 O species in a fuel-rich ethylene-oxygen flame revealed the presence of substantial concentrations of ethenol ͑vinyl alcohol͒ and acetaldehyde. Ethenol has not been previously detected in hydrocarbon flames. Absolute photoionization cross sections were measured for ethylene, allene, propyne, and acetaldehyde, using propene as a calibration standard. PIE curves are presented for several additional reaction intermediates prominent in hydrocarbon flames.

Many studies have been conducted on the environmental impacts of combustion generated aerosols. Due to their complex composition and morphology, their chemical reactivity is not well understood and new developments of analysis methods are needed. We report the first demonstration of in-flight X-ray based characterizations of freshly emitted soot particles, which is of paramount importance for understanding the role of one of the main anthropogenic particulate contributors to global climate change. Soot particles, produced by a burner for several air-to-fuel ratios, were injected through an aerodynamic lens, focusing them to a region where they interacted with synchrotron radiation. X-ray photoelectron spectroscopy and carbon K-edge near-edge X-ray absorption spectroscopy were performed and compared to those obtained for supported samples. A good agreement is found between these samples, although slight oxidation is observed for supported samples. Our experiments demonstrate that NEXAFS characterization of supported samples provides relevant information on soot composition, with limited effects of contamination or ageing under ambient storage conditions. The highly surface sensitive XPS experiments of airborne soot indicate that the oxidation is different at the surface as compared to the bulk probed by NEXAFS. We also report changes in soot’s work function obtained at different combustion conditions.

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The North African regions boast a multimillenary tradition of pottery production that represents a decisive progress in all societies. In this paper, we present the analysis of several fragments of pottery dating from the Middle Ages and collected in the archaeological site of Gouraya in Béjaïa (Algeria). Energy‐dispersive X‐ray fluorescence measurements were performed to obtain the elemental composition of the clays and to attempt a classification of the samples through multivariate analysis methods, connecting them to the archaeological information about the sites. Hierarchical clusters analysis (HCA) identified two possible different groups, related to different production sites, even if only one source of clay seem to be used, consistently with the geological contest. Based on the results, a tentative provenance interpretation could be proposed on historical bases. We put in place a strategy that made it possible to perform provenance studies respecting sample integrity as we aim to extend our research also to integer and well‐preserved object from museum, to create a database for Algerian production of in the Middle Ages.