An inexpensive transmittance and fluorescence meter

dc.contributor.author	Δρακόπουλος, Πάνος	el
dc.contributor.author	Χανδρινός, Άρης Β. (1958-)	el
dc.contributor.author	Ντούνας, Κώστας	el
dc.contributor.author	Νομικός, Κωνσταντίνος Δ.	el
dc.contributor.author	Πούλος, Σεραφείμ	el
dc.date.accessioned	2015-01-21T10:09:21Z
dc.date.available	2015-01-21T10:09:21Z
dc.date.issued	2015-01-21
dc.identifier.uri	http://hdl.handle.net/11400/4407
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ηνωμένες Πολιτείες	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/us/	*
dc.subject	Ocean optics
dc.subject	Optical instruments--Congresses
dc.subject	Environmental monitoring--Congresses
dc.subject	Οπτική ωκεανού
dc.subject	Οπτικά όργανα
dc.subject	Περιβαλλοντική παρακολούθηση
dc.title	An inexpensive transmittance and fluorescence meter	en
heal.type	conferenceItem
heal.classification	Ophthalmology
heal.classification	Optics
heal.classification	Οφθαλμολογία
heal.classification	Οπτική
heal.classificationURI	http://skos.um.es/unescothes/C02842
heal.classificationURI	http://skos.um.es/unescothes/C02847
heal.classificationURI	N/A-Οφθαλμολογία
heal.classificationURI	N/A-Οπτική
heal.keywordURI	http://id.loc.gov/authorities/subjects/sh2008108672
heal.keywordURI	http://id.loc.gov/authorities/subjects/sh2008102519
heal.contributorName	Θάνος, Ιωάννης	el
heal.contributorName	Ζερβάκης, Βασίλης	el
heal.language	en
heal.access	free
heal.recordProvider	Τ.Ε.Ι. Αθήνας, Σχολή Επαγγελμάτων Υγείας & Πρόνοιας, Τμήμα Οπτικής & Οπτομετρίας	el
heal.publicationDate	2007-09-05
heal.bibliographicCitation	Drakopoulos, P.G., Chandrinos, A., Doumas, C., Nomikos, S., Poulos, S., et.al (2007). An inexpensive transmittance and fluorescence meter. 10th International Conference on Environmental Science and Technology, Kos, Greece. 5-7/9/2007, pp B120-B126. Available from: http://www.srcosmos.gr/srcosmos/showpub.aspx?aa=9896%20	el
heal.abstract	Optical instruments are traditionally used for monitoring the state of coastal waters It is achieved by measuring specific inherent optical properties, such as scattering, absorption, beam attenuation and fluorescence. Backscattering and beam attenuation are re-suspension surrogates, while absorption and fluorescence are CDOM and chlorophyll indicators. Although latest achievements in optical technology have allowed for even more sophisticated sensing devices, most existing instruments target the scientific community and can be very expensive. In this project, the main goal is to build a cheap but reliable optical instrument using widely available off the shelf components. It is targeted to measure beam attenuation, backscattering, and fluorescence. The instrument in its final field version, will aim towards groups involved in activities such as coastal engineering, water pollution monitoring in recreation areas and fish-farming. At this stage the beam attenuation (transmittance) mode has been implemented in the laboratory and we present the first results. The beam attenuation configuration incorporates a GaAlAs ultra-bright LED emitting at 660 nm where CDOM absorption is negligible. After light is collimated, it travels through an attenuation path 130 mm long and refocused to a silicon photodiode fitted with a red filter to reduce ambient light. The LED is driven by a current modulated at 1 KHz to eliminate stray light through a stage of selective gain. The reverse biased photodiode wired to a trans-impedance mode operational amplifier to ensure linear response. The output of this signal is then further amplified, filtered and passed through a low-power, precision, true rms-to-dc converter. Calibration and performance testing of the instrument was carried out with suspensions of kaolin in concentrations ranging from 125 mg/l down to 1 mg/l and pure water. The procedure involved the preparation of an initial kaolin suspension which was successively diluted by adding distilled water to produce several samples. The instrument’s response to concentrations up to 62 mg/l was found to be notably linear (correlation coefficient 0.997). Laboratory experiments are in progress for the pure scattering and fluorescence modes. Again the same electronics are used, however the geometry changes. For chlorophyll fluorescence measurements, the sample excitation is achieved by two opposite facing ultra-bright LEDs emitting at 470 nm and fitted at an angle of 40 degrees to the photodiode. In the final field prototype, the device will be enclosed in a black acetal housing having an overall length not exceeding 35 cm.	en
heal.fullTextAvailability	true
heal.conferenceName	International Conference on Environmental Science and Technology	el
heal.conferenceItemType	full paper