{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T12:43:28Z","timestamp":1779281008653,"version":"3.51.4"},"reference-count":37,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2024,11,27]],"date-time":"2024-11-27T00:00:00Z","timestamp":1732665600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Japan Society for the Promotion of Science (JSPS)","award":["Grant 23K22894"],"award-info":[{"award-number":["Grant 23K22894"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Techniques for monitoring calcium carbonate and silica deposits (scale) in geothermal power plants and hot spring facilities using fiber optic sensors have already been reported. These sensors continuously measure changes in light transmittance with a detector and, when applied to field tests, require the installation of a power supply and sensor monitoring equipment. However, on some sites, a power supply may not be available, or a specialist skilled in handling scale sensors is required. To overcome this problem, we have developed a method for evaluating scale formation that is based on a batch process that can be used by anyone. In brief, this method involves depositing scale on a section of the optical fiber sensor and then fusing this section to the optical fiber and measuring it. Using this sensor, a technician in the field can simply place the sensor in the desired location, collect the samples at any given time, and send them to the laboratory to measure their transmittance. This simple and easy method was achieved by using a hetero-core type of fiber optic. This evaluation method can measure with the same sensitivity as conventional real-time methods, while its transmittance response for the sensor corresponds to the saturation index (SI) changes in the scale components in the solution due to increases in temperature and concentration. In the field of carbon dioxide capture and storage (CCS), this evaluation method can be used to quantitatively measure the formation of carbonate minerals, and it can also be used as an indicator for determining the conditions for CO2 mineral fixation, as well as in experiments using batch-type autoclaves in laboratory testing. It is also expected to be used in geothermal power plants as a method for evaluating scale formation, such as that of amorphous silica, and to protect against agents that hinder stable operation.<\/jats:p>","DOI":"10.3390\/s24237580","type":"journal-article","created":{"date-parts":[[2024,11,27]],"date-time":"2024-11-27T10:05:56Z","timestamp":1732701956000},"page":"7580","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["A Novel Technique for Monitoring Carbonate and Scale Precipitation Using a Batch-Process-Based Hetero-Core Fiber Optic Sensor"],"prefix":"10.3390","volume":"24","author":[{"given":"Sakurako","family":"Satake","sequence":"first","affiliation":[{"name":"Graduate School of Sustainability Studies for Research, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ai","family":"Hosoki","sequence":"additional","affiliation":[{"name":"Department of Natural and Environmental Sciences, Faculty of Science, Academic Assembly, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan"},{"name":"Graduate School of Engineering Science, Akita University, Akita 010-8502, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9102-3667","authenticated-orcid":false,"given":"Hideki","family":"Kuramitz","sequence":"additional","affiliation":[{"name":"Department of Natural and Environmental Sciences, Faculty of Science, Academic Assembly, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1476-3933","authenticated-orcid":false,"given":"Akira","family":"Ueda","sequence":"additional","affiliation":[{"name":"Department of Natural and Environmental Sciences, Faculty of Science, Academic Assembly, University of Toyama, Gofuku 3190, Toyama 930-8555, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2024,11,27]]},"reference":[{"key":"ref_1","unstructured":"Brown, K.L., and McDowell, G.D. (1987, January 11\u201313). pH control of silica scaling. Proceedings of the 5th New Zealand Geothermal Workshop, Auckland, New Zealand."},{"key":"ref_2","first-page":"749","article-title":"Brine pH modification scale control technology","volume":"20","author":"Gallup","year":"1996","journal-title":"Geotherm. Resour. Counc. Trans."},{"key":"ref_3","first-page":"49","article-title":"The interaction of silicic acid with sulfurous acid scale inhibitor","volume":"21","author":"Gallup","year":"1997","journal-title":"Geotherm. Resour. Counc. Trans."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.geothermics.2017.07.001","article-title":"Recovery of oversaturated silica from Takigami and Sumikawa geothermal brines with cationic polymer flocculants to prevent silica scale deposition","volume":"70","author":"Hanajima","year":"2017","journal-title":"Geothermics"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/0375-6505(95)00043-7","article-title":"Scale prevention method by brine acidification with biochemical reactors","volume":"25","author":"Hirowatari","year":"1996","journal-title":"Geothermics"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1016\/j.geothermics.2017.06.017","article-title":"Experimental field investigations of inhibitors for controlling silica scale in geothermal brine at the Sumikawa geothermal plant, Akita Prefecture, Japan","volume":"70","author":"Ikeda","year":"2017","journal-title":"Geothermics"},{"key":"ref_7","first-page":"229","article-title":"Study on the decrease of reservoir permeability due to the deposition of silica dissolved in the reinjection","volume":"8","author":"Itoi","year":"1986","journal-title":"J. Jpn. Geotherm. Soc."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"415","DOI":"10.1016\/S0375-6505(02)00004-4","article-title":"Investigation of organic inhibitors for silica scale control in geothermal brines","volume":"31","author":"Gallup","year":"2002","journal-title":"Geothermics"},{"key":"ref_9","first-page":"163","article-title":"Investigation of pH control method to avoid silica scaling in the Sumikawa geothermal field","volume":"25","author":"Ueda","year":"2003","journal-title":"J. Jpn. Geotherm. Soc."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"737","DOI":"10.1016\/S0375-6505(00)00027-4","article-title":"Deposition of amorphous silica in porous packed beds: Predicting the lifetime of reinjection aquifers","volume":"29","author":"Mroczek","year":"2000","journal-title":"Geothermics"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"114","DOI":"10.1016\/j.geothermics.2019.01.002","article-title":"Prediction of permeability reduction due to silica scale deposition with a geochemical clogging model at Sumikawa Geothermal Power Plant","volume":"79","author":"Yanaze","year":"2019","journal-title":"Geothermics"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"177","DOI":"10.2116\/analsci.31.177","article-title":"Fundamental study on the development of fiber optic sensor for real-time sensing of CaCO3 scale formation in geothermal water","volume":"31","author":"Okazaki","year":"2015","journal-title":"Anal. Sci."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Okazaki, T., Orii, T., Ueda, A., Ozawa, A., and Kuramitz, H. (2017). Fiber optic sensor for real-time sensing of silica scale formation in geothermal water. Sci. Rep., 7.","DOI":"10.1038\/s41598-017-03530-1"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2000104","DOI":"10.1109\/LSENS.2017.2739806","article-title":"Fiber optic sensor with an optically transparent electrode for monitoring CaCO3 scale formation in geothermal water","volume":"1","author":"Okazaki","year":"2017","journal-title":"IEEE Sens. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Okazaki, T., Umeki, S., Orii, T., Ikeya, R., Sakaguchi, A., Yamamoto, T., Watanabe, T., Ueda, A., and Kuramitz, H. (2019). Investigation of the effects of electromagnetic field treatment of hot spring water for scale inhibition using a fiber optic sensor. Sci. Rep., 9.","DOI":"10.1038\/s41598-019-47088-6"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"2160","DOI":"10.1080\/00032719.2020.1732400","article-title":"U-shaped polymer cladding and hetero-core fiber optic sensors for monitoring scale formation in geothermal brine","volume":"53","author":"Okazaki","year":"2020","journal-title":"Anal. Lett."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"102069","DOI":"10.1016\/j.geothermics.2021.102069","article-title":"Scale sensor: Rapid monitoring of scale deposition and inhibition using fiber optics in a geothermal system and comparison with other monitoring devices","volume":"93","author":"Okazaki","year":"2021","journal-title":"Geothermics"},{"key":"ref_18","first-page":"309","article-title":"Macrobending characteristics of a hetero-core splice fiber optic sensor for displacement and liquid detection","volume":"83","author":"Watanabe","year":"2000","journal-title":"IEICE Trans. Electron."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1016\/S0925-4005(03)00530-6","article-title":"Acidity measurements based on a hetero-sore structured fiber optic sensor","volume":"96","author":"Iga","year":"2003","journal-title":"Sens. Actuators B"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"154","DOI":"10.1016\/j.aca.2006.08.061","article-title":"A hetero-core structured fiber optic pH sensor","volume":"582","author":"Seki","year":"2007","journal-title":"Anal. Chim. Acta"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"6638","DOI":"10.1109\/JSEN.2023.3246056","article-title":"Triaxial accelerometer based on a semicircular hetero-core fiber-optic sensor","volume":"23","author":"Kadokura","year":"2023","journal-title":"IEEE Sens. J."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"110045","DOI":"10.1016\/j.optlastec.2023.110045","article-title":"Lipid-coated hetero-core optical fiber sensor for wide-range chemical detection","volume":"169","author":"Hosoki","year":"2024","journal-title":"Opt. Laser Technol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1149","DOI":"10.1016\/0196-8904(95)00308-8","article-title":"An overview of the Joule II project \u201cThe underground disposal of carbon dioxide\u201d","volume":"37","author":"Holloway","year":"1996","journal-title":"Energy Convers. Manag."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1329","DOI":"10.1016\/j.energy.2004.03.068","article-title":"Geological storage of CO2: What do we know, where are the gaps and what more needs to be done?","volume":"29","author":"Gale","year":"2004","journal-title":"Energy"},{"key":"ref_25","unstructured":"Metz, B. (2005). Carbon Dioxide Capture and Storage, Cambridge University Press."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"119909","DOI":"10.1016\/j.chemgeo.2020.119909","article-title":"Mineral dissolution and precipitation reactions and their net balance controlled by mineral surface area: An experimental study on the interactions between continental flood basalts and CO2-saturated water at 80 bars and 60 \u00b0C","volume":"559","author":"Phukan","year":"2021","journal-title":"Chem. Geol."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"1983","DOI":"10.1038\/s41467-019-10003-8","article-title":"Rapid CO2 mineralization into calcite at the CarbFix storage site quantified using calcium isotopes","volume":"10","author":"Burton","year":"2019","journal-title":"Nat. Commun."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"146","DOI":"10.1016\/j.chemgeo.2012.03.006","article-title":"Mineralogical aspects of CO2 sequestration during hydrothermal basalt alteration\u2014An experimental study at 75 to 250 \u00b0C and elevated pCO2","volume":"306\u2013307","author":"Gysi","year":"2012","journal-title":"Chem. Geol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1016\/j.gca.2020.01.004","article-title":"Experimental study on mafic rock dissolution rates within CO2-seawater-rock systems","volume":"272","author":"Marieni","year":"2020","journal-title":"Geochim. Cosmochim. Acta"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1016\/j.gca.2021.05.056","article-title":"An experimental study of basalt\u2013seawater\u2013CO2 interaction at 130 \u00b0C","volume":"308","author":"Voigt","year":"2021","journal-title":"Geochim. Cosmochim. Acta"},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Heine, I., Brauer, A., Heim, B., Itzerott, S., Kasprzak, P., Kienel, U., and Kleinschmit, B. (2017). Monitoring of calcite precipitation in hardwater lakes with multi-spectral remote sensing archives. Water, 9.","DOI":"10.3390\/w9010015"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"104906","DOI":"10.1016\/j.apgeochem.2021.104906","article-title":"A fibre-optical method for monitoring barite precipitation at high pressure\/high temperature conditions","volume":"127","author":"Zotzmann","year":"2021","journal-title":"Appl. Geochem."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"105214","DOI":"10.1016\/j.cemconcomp.2023.105214","article-title":"In situ monitoring of the hydration of calcium silicate minerals in cement with a remote fiber-optic Raman probe","volume":"142","author":"Zhang","year":"2023","journal-title":"Cem. Concr."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"137719","DOI":"10.1016\/j.electacta.2021.137719","article-title":"Real-time monitoring of electrochemically induced calcium carbonate depositions: Kinetics and mechanisms","volume":"370","author":"Liu","year":"2021","journal-title":"Electrochim. Acta"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1639","DOI":"10.1021\/ac970942v","article-title":"Near-ultraviolet evanescent-wave absorption sensor based on a multimode optic fiber","volume":"70","author":"Potyrailo","year":"1998","journal-title":"Anal. Chem."},{"key":"ref_36","unstructured":"Parkhurst, D.L., and Appelo, C.A.J. (1999). Users Guide to PHREEQC (Version 2)\u2014A Computer Program for Speciation, Batch-Reaction, One-Dimensional Transport, and Inverse Geochemical Calculations, Water-Resources Investigations Report 99-4259."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"89","DOI":"10.2320\/jinstmet.J2016045","article-title":"Effect of Ions Eluted from Metal Surface on Transformation and Growth of Calcium Carbonate Polymorphisms","volume":"81","author":"Hashimoto","year":"2017","journal-title":"J. Jpn. Inst. Met. Mater."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/23\/7580\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:40:50Z","timestamp":1760114450000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/23\/7580"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,11,27]]},"references-count":37,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2024,12]]}},"alternative-id":["s24237580"],"URL":"https:\/\/doi.org\/10.3390\/s24237580","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,11,27]]}}}