{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,1]],"date-time":"2025-11-01T21:46:03Z","timestamp":1762033563923,"version":"build-2065373602"},"reference-count":28,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2018,9,14]],"date-time":"2018-09-14T00:00:00Z","timestamp":1536883200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100006284","name":"Pipeline and Hazardous Materials Safety Administration","doi-asserted-by":"publisher","award":["DTPH56-15-H-CAAP06"],"award-info":[{"award-number":["DTPH56-15-H-CAAP06"]}],"id":[{"id":"10.13039\/100006284","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Insoluble liquids show layers such as water and oil. The detection of the exact interface locations and the level changes for layered liquids are of paramount importance for chemistry purifications, liquid storage in reservoirs, oil transportation, and chemical engineering. However, accurately measuring liquid layers is challenging. This paper introduces a multi-parameter sensing device based on a long-period fiber grating (LPFG) sensor simultaneously detecting boundary and level changes of layered liquids. Laboratory experiments demonstrated that the sensor device would respond to the liquid interface change as a sharp and sudden resonant wavelength change, while it would show a gradual and steady resonant wavelength change to the level changes of layered liquids. The lab experiments also showed that the sensor device has a higher sensitivity when a higher LPFG cladding mode is used.<\/jats:p>","DOI":"10.3390\/s18093094","type":"journal-article","created":{"date-parts":[[2018,9,14]],"date-time":"2018-09-14T10:57:59Z","timestamp":1536922679000},"page":"3094","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Multi-Parameter Sensing Device to Detect Liquid Layers Using Long-Period Fiber Gratings"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4570-9078","authenticated-orcid":false,"given":"Zhihui","family":"Pan","sequence":"first","affiliation":[{"name":"School of Civil Engineering, Guangzhou University, Guangzhou 510006, China"},{"name":"Department of Civil and Environmental Engineering, North Dakota State University, 1340 Administration Ave, Fargo, ND 58108, USA"}]},{"given":"Ying","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Civil and Environmental Engineering, North Dakota State University, 1340 Administration Ave, Fargo, ND 58108, USA"}]},{"given":"Hai","family":"Xiao","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Clemson University, Clemson, SC 29634, USA"}]}],"member":"1968","published-online":{"date-parts":[[2018,9,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Beutel, T., Ferreira, N., Leester-Sch\u00e4del, M., and B\u00fcttgenbach, S. 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