This paper presents experimental and numerical studies on spray painting processes by using airless spray guns for ship painting. A computational fluid dynamics code was applied to calculate the flow field and the dro...This paper presents experimental and numerical studies on spray painting processes by using airless spray guns for ship painting. A computational fluid dynamics code was applied to calculate the flow field and the droplet trajectories. Droplet size distributions and droplet velocities as necessary inlet characteristics for the simulations were experimentally obtained using a Spraytec Fraunhofer type particle sizer and laser-Doppler anemometry. Effects of shoreline winds and painting distance on the transfer efficiency and on the paint film thickness distributions on the target were numerically studied.展开更多
Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system,such as Mars,the moon,and asteroids.To date,the origin mechanisms of perchlorate and chlorate on the Martia...Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system,such as Mars,the moon,and asteroids.To date,the origin mechanisms of perchlorate and chlorate on the Martian surface have been well-established;however,relatively little attention has been cast to airless bodies.Here,we experimentally investigated the potential oxidation mechanisms of chloride to chlorate and perchlorate,such as ultraviolet irradiation under H_(2)O-and O_(2)-free conditions and mechanical pulverization processes.Individual minerals,olivine,pyroxene,ilmenite,magnetite,TiO_(2)and anhydrous ferric sulfate,and lunar regolith simulants(low Ti,CLRS-1;high-Ti,CLRS-2)and their metallic iron(Fe^( 0))bearing counterparts were examined.We found that pulverization of dry matrix material-halite mixtures,even in the presence of O_(2),does not necessarily lead to perchlorate and chlorate formation without involving water.Under photocatalytic and H_(2)O and O_(2)-free conditions,olivine and pyroxene can produce oxychlorine(ClO_(x)^(−))species,although the yields were orders of magnitude lower than those under Martian-relevant conditions.Nanophase-Fe^(0)particles in the lunar regolith and the common photocatalyst TiO_(2)can facilitate the ClO_(x)^(−)formation,but their yields were lower than those with olivine.The oxides ilmenite and magnetite did not efficiently contribute to ClO_(x)^(−)production.Our results highlight the critical role of H_(2)O in the oxidation chloride to chlorate and perchlorate,and provide essential insights into the environmental influence on the formation of oxychlorine species on different celestial bodies.展开更多
文摘This paper presents experimental and numerical studies on spray painting processes by using airless spray guns for ship painting. A computational fluid dynamics code was applied to calculate the flow field and the droplet trajectories. Droplet size distributions and droplet velocities as necessary inlet characteristics for the simulations were experimentally obtained using a Spraytec Fraunhofer type particle sizer and laser-Doppler anemometry. Effects of shoreline winds and painting distance on the transfer efficiency and on the paint film thickness distributions on the target were numerically studied.
基金supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences(XDB41000000)the National Natural Science Foundation of China(42373042)+3 种基金the National Key Scientifi c Instrument and Equipment Development Project(2012YQ090229)the Scientifi c Instrument Upgrading Project of Shandong Province(2012SGGZ18)the Key Research Program of the Chinese Academy of Sciences(ZDBS-SSWTLC001)the Program of the Institute of Geology&Geophysics CAS(IGGCAS-201905).
文摘Perchlorate and chlorate are present in various extraterrestrial celestial bodies throughout the solar system,such as Mars,the moon,and asteroids.To date,the origin mechanisms of perchlorate and chlorate on the Martian surface have been well-established;however,relatively little attention has been cast to airless bodies.Here,we experimentally investigated the potential oxidation mechanisms of chloride to chlorate and perchlorate,such as ultraviolet irradiation under H_(2)O-and O_(2)-free conditions and mechanical pulverization processes.Individual minerals,olivine,pyroxene,ilmenite,magnetite,TiO_(2)and anhydrous ferric sulfate,and lunar regolith simulants(low Ti,CLRS-1;high-Ti,CLRS-2)and their metallic iron(Fe^( 0))bearing counterparts were examined.We found that pulverization of dry matrix material-halite mixtures,even in the presence of O_(2),does not necessarily lead to perchlorate and chlorate formation without involving water.Under photocatalytic and H_(2)O and O_(2)-free conditions,olivine and pyroxene can produce oxychlorine(ClO_(x)^(−))species,although the yields were orders of magnitude lower than those under Martian-relevant conditions.Nanophase-Fe^(0)particles in the lunar regolith and the common photocatalyst TiO_(2)can facilitate the ClO_(x)^(−)formation,but their yields were lower than those with olivine.The oxides ilmenite and magnetite did not efficiently contribute to ClO_(x)^(−)production.Our results highlight the critical role of H_(2)O in the oxidation chloride to chlorate and perchlorate,and provide essential insights into the environmental influence on the formation of oxychlorine species on different celestial bodies.
