{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,21]],"date-time":"2026-02-21T20:27:20Z","timestamp":1771705640446,"version":"3.50.1"},"reference-count":45,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2018,5,5]],"date-time":"2018-05-05T00:00:00Z","timestamp":1525478400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003407","name":"Ministero dell\u2019Istruzione, dell\u2019Universit\u00e0 e della Ricerca","doi-asserted-by":"publisher","award":["Tecnologie OPTOelettroniche innovative per il monitoraggio e la diagnostica dell\u2019infrastruttura FERroviaria OPTOFER PON03PE_00155_1"],"award-info":[{"award-number":["Tecnologie OPTOelettroniche innovative per il monitoraggio e la diagnostica dell\u2019infrastruttura FERroviaria OPTOFER PON03PE_00155_1"]}],"id":[{"id":"10.13039\/501100003407","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this work, we report the in-field demonstration of a liquefied petroleum gas monitoring system based on optical fiber technology. Long-period grating coated with a thin layer of atactic polystyrene (aPS) was employed as a gas sensor, and an array comprising two different fiber Bragg gratings was set for the monitoring of environmental conditions such as temperature and humidity. A custom package was developed for the sensors, ensuring their suitable installation and operation in harsh conditions. The developed system was installed in a real railway location scenario (i.e., a southern Italian operative railway tunnel), and tests were performed to validate the system performances in operational mode. Daytime normal working operations of the railway line and controlled gas expositions, at very low concentrations, were the searched realistic conditions for an out-of-lab validation of the developed system. Encouraging results were obtained with a precise indication of the gas concentration and external conditioning of the sensor.<\/jats:p>","DOI":"10.3390\/s18051435","type":"journal-article","created":{"date-parts":[[2018,5,7]],"date-time":"2018-05-07T03:12:21Z","timestamp":1525662741000},"page":"1435","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Liquefied Petroleum Gas Monitoring System Based on Polystyrene Coated Long Period Grating"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-1187-5825","authenticated-orcid":false,"given":"Flavio","family":"Esposito","sequence":"first","affiliation":[{"name":"Department of Engineering, University of Naples \u201cParthenope\u201d, 80143 Napoli, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3369-3328","authenticated-orcid":false,"given":"Aldobenedetto","family":"Zotti","sequence":"additional","affiliation":[{"name":"Institute for Polymers, Composites and Biomaterials (IPCB)-CNR, 80055 Portici, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Giovanna","family":"Palumbo","sequence":"additional","affiliation":[{"name":"Department of Engineering, University of Naples \u201cParthenope\u201d, 80143 Napoli, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Simona","family":"Zuppolini","sequence":"additional","affiliation":[{"name":"Institute for Polymers, Composites and Biomaterials (IPCB)-CNR, 80055 Portici, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marco","family":"Consales","sequence":"additional","affiliation":[{"name":"Optoelectronics group, Department of Engineering, University of Sannio, 82100 Benevento, Italy"},{"name":"Centro Regionale Information Communication Technology-CeRICT scrl, 82100 Benevento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Antonello","family":"Cutolo","sequence":"additional","affiliation":[{"name":"Optoelectronics group, Department of Engineering, University of Sannio, 82100 Benevento, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anna","family":"Borriello","sequence":"additional","affiliation":[{"name":"Institute for Polymers, Composites and Biomaterials (IPCB)-CNR, 80055 Portici, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2987-9122","authenticated-orcid":false,"given":"Stefania","family":"Campopiano","sequence":"additional","affiliation":[{"name":"Department of Engineering, University of Naples \u201cParthenope\u201d, 80143 Napoli, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5018-5512","authenticated-orcid":false,"given":"Mauro","family":"Zarrelli","sequence":"additional","affiliation":[{"name":"Institute for Polymers, Composites and Biomaterials (IPCB)-CNR, 80055 Portici, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Agostino","family":"Iadicicco","sequence":"additional","affiliation":[{"name":"Department of Engineering, University of Naples \u201cParthenope\u201d, 80143 Napoli, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2018,5,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"R125","DOI":"10.1088\/0022-3727\/34\/19\/201","article-title":"Function and applications of gas sensors","volume":"34","author":"Kohl","year":"2001","journal-title":"J. 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