{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T05:39:38Z","timestamp":1773812378481,"version":"3.50.1"},"reference-count":39,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2022,2,7]],"date-time":"2022-02-07T00:00:00Z","timestamp":1644192000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006182","name":"Funda\u00e7\u00e3o de Amparo \u00e0 Pesquisa do Esp\u00edrito Santo","doi-asserted-by":"publisher","award":["84336650"],"award-info":[{"award-number":["84336650"]}],"id":[{"id":"10.13039\/501100006182","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004225","name":"Petrobras (Brazil)","doi-asserted-by":"publisher","award":["2017\/00702-6"],"award-info":[{"award-number":["2017\/00702-6"]}],"id":[{"id":"10.13039\/501100004225","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["UIDB\/50025\/2020"],"award-info":[{"award-number":["UIDB\/50025\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["UIDP\/50025\/2020"],"award-info":[{"award-number":["UIDP\/50025\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["CEECIND\/00034\/2018"],"award-info":[{"award-number":["CEECIND\/00034\/2018"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This paper presents a fiber optic, liquid level sensor system based on a pair of fiber Bragg gratings (FBGs), embedded in a circular silicone (PDMS\u2014polydimethylsiloxane) rubber diaphragm. The measurement principles of this sensor, whose diaphragm structure is about 2.2 mm thick with 45 mm in diameter, are introduced. To analyze the linearity and sensitivity of the sensor, the diaphragm was subjected to compression tests as well as to liquid level loading and unloading. The force and liquid level increase tests showed that inserting two FBGs (0.99453 for force and 0.99163 for liquid level) in the diaphragm resulted in a system with greater linearity than that with individual FBGs. This occurred where FBG1 showed 0.97684 for force and 0.98848 for liquid level and FBG2 presented 0.89461 for force and 0.93408 for liquid level. However, the compression and water level decrease tests showed that the system (R2 = 0.97142) had greater linearity with FBG2 (0.94123) and lower linearity with FBG1 (0.98271). Temperature characterization was also performed, and we found that sensitivity to FBG1 temperature variation was 11.73 pm\/\u00b0C and for FGB2 it was 10.29 pm\/\u00b0C. Temperature sensitivity was improved for both FBGs when compared with uncoated FBGs with typical values of 9.75 pm\/\u00b0C. Therefore, the proposed FBG-based sensor system is capable of simultaneous measurement of force and temperature in a compact diaphragm-embedded system.<\/jats:p>","DOI":"10.3390\/s22031268","type":"journal-article","created":{"date-parts":[[2022,2,7]],"date-time":"2022-02-07T20:36:42Z","timestamp":1644266202000},"page":"1268","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Liquid Level Sensor with Two FBGs Embedded in a PDMS Diaphragm: Analysis of the Linearity and Sensitivity"],"prefix":"10.3390","volume":"22","author":[{"given":"Eliton","family":"Morais","sequence":"first","affiliation":[{"name":"Graduate Program in Electrical Engineering, Federal University of Espirito Santo (UFES), Vitoria 29075-910, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9009-2425","authenticated-orcid":false,"given":"Maria Jos\u00e9","family":"Pontes","sequence":"additional","affiliation":[{"name":"Graduate Program in Electrical Engineering, Federal University of Espirito Santo (UFES), Vitoria 29075-910, Brazil"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8596-5092","authenticated-orcid":false,"given":"Carlos","family":"Marques","sequence":"additional","affiliation":[{"name":"Physics Department & I3N, University of Aveiro, 3810-193 Aveiro, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9075-0619","authenticated-orcid":false,"given":"Arnaldo","family":"Leal-Junior","sequence":"additional","affiliation":[{"name":"Graduate Program in Electrical Engineering, Federal University of Espirito Santo (UFES), Vitoria 29075-910, Brazil"}]}],"member":"1968","published-online":{"date-parts":[[2022,2,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"62","DOI":"10.1016\/j.optlastec.2015.09.004","article-title":"Developments in optical fibre sensors for industrial applications","volume":"78","author":"Alwis","year":"2016","journal-title":"Opt. 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