Sruthy Poulose;Yara Alvarez-Braña;Lourdes Basabel-Desmonts;Fernando Benito-Lopez;John Michael David Coey
{"title":"密闭空间中水蒸发的磁场增强","authors":"Sruthy Poulose;Yara Alvarez-Braña;Lourdes Basabel-Desmonts;Fernando Benito-Lopez;John Michael David Coey","doi":"10.1109/LMAG.2023.3262976","DOIUrl":null,"url":null,"abstract":"Water is studied in confined environments where it evaporates into its own vapor. Simultaneous experiments are conducted for 0.4–0.5 µL droplets confined at the center of 54 mm long microchannels with a cross section of 0.38 mm\n<sup>2</sup>\n in the presence and absence of a 300 mT magnetic field. Results are compared with those for water in half-filled 100 mL beakers. The magnetic enhancement of the evaporation rate is much greater in the microchannels, where effects range up to 140% even though the air is saturated with water vapor, as compared to 12 ± 7% in a 500 mT field in the beakers. The average steady state, no-field evaporation rate of 0.13 kg\n<inline-formula><tex-math>$\\cdot$</tex-math></inline-formula>\nm\n<sup>−2</sup>\n<inline-formula><tex-math>$\\cdot$</tex-math></inline-formula>\nh\n<sup>−1</sup>\n in the microchannels is roughly double that in the beakers, but less than the value expected at an open surface in still air. The magnetic enhancement is analyzed in terms of the \n<italic>ortho</i>\n and \n<italic>para</i>\n nuclear isomers of water vapor, which behave as independent gasses. The \n<italic>ortho:para</i>\n ratio in fresh vapor is close to 2:3, and quite different from the 3:1 equilibrium ratio in ambient air. Evaporation is increased by the gradient of the applied magnetic field, which dephases the Larmor precession of the two proton spins of hydrogen in a water molecule and tends to equalize the isomeric populations in the vapor, thereby increasing the evaporation rate.","PeriodicalId":13040,"journal":{"name":"IEEE Magnetics Letters","volume":"14 ","pages":"1-5"},"PeriodicalIF":1.1000,"publicationDate":"2023-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/iel7/5165412/10018138/10092455.pdf","citationCount":"0","resultStr":"{\"title\":\"Magnetic Field Enhancement of Water Evaporation in Confined Spaces\",\"authors\":\"Sruthy Poulose;Yara Alvarez-Braña;Lourdes Basabel-Desmonts;Fernando Benito-Lopez;John Michael David Coey\",\"doi\":\"10.1109/LMAG.2023.3262976\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Water is studied in confined environments where it evaporates into its own vapor. Simultaneous experiments are conducted for 0.4–0.5 µL droplets confined at the center of 54 mm long microchannels with a cross section of 0.38 mm\\n<sup>2</sup>\\n in the presence and absence of a 300 mT magnetic field. Results are compared with those for water in half-filled 100 mL beakers. The magnetic enhancement of the evaporation rate is much greater in the microchannels, where effects range up to 140% even though the air is saturated with water vapor, as compared to 12 ± 7% in a 500 mT field in the beakers. The average steady state, no-field evaporation rate of 0.13 kg\\n<inline-formula><tex-math>$\\\\cdot$</tex-math></inline-formula>\\nm\\n<sup>−2</sup>\\n<inline-formula><tex-math>$\\\\cdot$</tex-math></inline-formula>\\nh\\n<sup>−1</sup>\\n in the microchannels is roughly double that in the beakers, but less than the value expected at an open surface in still air. The magnetic enhancement is analyzed in terms of the \\n<italic>ortho</i>\\n and \\n<italic>para</i>\\n nuclear isomers of water vapor, which behave as independent gasses. The \\n<italic>ortho:para</i>\\n ratio in fresh vapor is close to 2:3, and quite different from the 3:1 equilibrium ratio in ambient air. Evaporation is increased by the gradient of the applied magnetic field, which dephases the Larmor precession of the two proton spins of hydrogen in a water molecule and tends to equalize the isomeric populations in the vapor, thereby increasing the evaporation rate.\",\"PeriodicalId\":13040,\"journal\":{\"name\":\"IEEE Magnetics Letters\",\"volume\":\"14 \",\"pages\":\"1-5\"},\"PeriodicalIF\":1.1000,\"publicationDate\":\"2023-04-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://ieeexplore.ieee.org/iel7/5165412/10018138/10092455.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"IEEE Magnetics Letters\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://ieeexplore.ieee.org/document/10092455/\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"ENGINEERING, ELECTRICAL & ELECTRONIC\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"IEEE Magnetics Letters","FirstCategoryId":"101","ListUrlMain":"https://ieeexplore.ieee.org/document/10092455/","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}
Magnetic Field Enhancement of Water Evaporation in Confined Spaces
Water is studied in confined environments where it evaporates into its own vapor. Simultaneous experiments are conducted for 0.4–0.5 µL droplets confined at the center of 54 mm long microchannels with a cross section of 0.38 mm
2
in the presence and absence of a 300 mT magnetic field. Results are compared with those for water in half-filled 100 mL beakers. The magnetic enhancement of the evaporation rate is much greater in the microchannels, where effects range up to 140% even though the air is saturated with water vapor, as compared to 12 ± 7% in a 500 mT field in the beakers. The average steady state, no-field evaporation rate of 0.13 kg
$\cdot$
m
−2$\cdot$
h
−1
in the microchannels is roughly double that in the beakers, but less than the value expected at an open surface in still air. The magnetic enhancement is analyzed in terms of the
ortho
and
para
nuclear isomers of water vapor, which behave as independent gasses. The
ortho:para
ratio in fresh vapor is close to 2:3, and quite different from the 3:1 equilibrium ratio in ambient air. Evaporation is increased by the gradient of the applied magnetic field, which dephases the Larmor precession of the two proton spins of hydrogen in a water molecule and tends to equalize the isomeric populations in the vapor, thereby increasing the evaporation rate.
期刊介绍:
IEEE Magnetics Letters is a peer-reviewed, archival journal covering the physics and engineering of magnetism, magnetic materials, applied magnetics, design and application of magnetic devices, bio-magnetics, magneto-electronics, and spin electronics. IEEE Magnetics Letters publishes short, scholarly articles of substantial current interest.
IEEE Magnetics Letters is a hybrid Open Access (OA) journal. For a fee, authors have the option making their articles freely available to all, including non-subscribers. OA articles are identified as Open Access.