Particulate matter 2.5 (PM2.5), collected from ambient air in Fukuoka City, was analyzed by gas chromatography combined with multiphoton ionization mass spectrometry using an ultraviolet femtosecond laser (267 nm) as the ionization source. Numerous parent polycyclic aromatic hydrocarbons (PPAHs) were observed in a sample extracted from PM2.5, and their concentrations were determined to be in the range from 30 to 190 pg/m(3) for heavy PPAHs. Standard samples of nitrated polycyclic aromatic hydrocarbons (NPAHs) were examined, and the limits of detection were determined to be in the picogram range. The concentration of NPAH adsorbed on PM2.5 in the air was less than 900-1300 pg/m(3). Graphical Abstract ᅟ.
Ammonium dinitramide-based energetic ionic liquid propellants (ADN-EILPs) exhibit the advantages of high energy density, low toxicity, and handling safety, and are therefore promising monopropellants. Herein, we characterized the ignition of ADN-EILPs induced by CW laser heating in the presence of carbon fibers, clarifying the effect of laser power and suggesting that ignition reproducibility is influenced by the difference of ADN-EILP osmotic state in carbon fibers or carbon fiber configuration. The observed ignition behavior allowed one to conclude that (i) high-power CW laser heating causes the formation of bubbles on the surface, which disturbs further heating; and (ii) an Arrhenius-type relationship exists between ignition delay and heating rate, suggesting that the strategy of foreshortening ADN-EILP ignition delay by increasing CW laser power has certain limits.
The ignition system for ammonium dinitramide‐based non‐solvent ionic liquids (ADN‐EILPs) with a continuous‐wave (CW) laser was investigated. The efficiency of conversion from CW laser power to ignition energy for ADN‐EILPs is important, and carbon additives are expected to enhance the efficiency of conversion. The impact of additive shapes on ADN‐EILP ignition by CW lasers is discussed herein by comparing the results of the ignition behavior observation using a high‐speed infrared camera. The shapes of the carbon additives are of two different types: fine fiber mass, called carbon wool, and powder of graphite. The ignition delay of carbon wool mixed ADN‐EILPs is shorter than that of the sample with graphite powder. The difference in these results might depend on the low dispersibility in ADN‐EILPs of carbon wools and the presence of local heat spots owing to the CW laser. The addition of carbon wools in ADN‐EILPs is expected to facilitate their ignition by CW laser heating.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.