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Fiber-optic Sensors for the Monitoring of Liquid Mixtures Optical Engineering, Feb. 26, 2014. Eyal Preter, 1 Vlada Artal, 1,2 Chaim N. Sukenik, 2 and Avi Zadok 1,* 1 Faculty of Engineering, Bar- Ilan University , Israel
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Fiber-optic Sensors for the Monitoring of Liquid MixturesOptical Engineering, Feb. 26, 2014 Eyal Preter,1Vlada Artal,1,2ChaimN. Sukenik,2 and Avi Zadok1,* 1Faculty of Engineering, Bar-Ilan University, Israel 2Departmaent of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Israel Avinoam.Zadok@biu.ac.il
How to monitor Evaporation? • Traditionally: • Direct observation: contact angle Goniometer • AFM cantilevers • Micro Gravimetry Accuracy Complicated Setup Limited accessibility 2 Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Objective Simple, low-cost fiber-optic sensor for monitoring the evaporation of liquids • Proof of concept • Evaporation-related data • Comparing with traditional methods • Applications Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
The Setup The Sensor: Cleaved Fiber The Input: Fixed Laser Source The Readout: Low Bandwidth Detector & Scope. PowerMeter Scope Circulator Laser Fiber Tip Resonator Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Principle of Operation • Light is launched from the remote end of the fiber, and the reflected power is monitored • Light is reflected at the fiber / liquid interface, and the liquid / air interface • The two reflections combined create interference, according to the thickness of the liquid droplet • As the liquid evaporates, interference fringes are observed: Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Typical Results: Raw Data Water Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Typical Results: Instantaneous Droplet Length Water Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Control Experiment Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Control Experiment Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Apps (1): Mixtures Study • Ethanol Concentration In Water Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Apps (1): Mixtures Study • Ethanol Concentration In Water Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Apps (2): Recognition of solvents: bare fiber tip Difficult to categorize 10 solvents based on evaporation time and droplet size alone Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Surface Modification • Surface treatment • Deposition of single layer (monolayer) hydrophobic coating. • The monolayer does not interact with the light, but changes the surface behave. Coated Fiber Normal Fiber Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Surface Modification Dynamics Coated Fiber Bare Fiber Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Evaporation from modified surfaces Acetone Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Droplet length on coated fiber: relation with polarity index Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Apps (2): Recognition of solvents: coated fiber tip Evaporation from coated fibers can distinguish between all 10 solvents through simple data analysis Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Apps (2): Recognition of solvents: combined analysis Solvents recognition based on the combined analysis of evaporation from both bare and coated fibers Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Apps (3): Recognition of flexible fuel blends • A Flex Fuel Sensor is a device that measures the ethanol content in the car’s fuel system. • The sensor is installed between the fuel pressure regulator and the fuel tank, where it monitors the ethanol content of the fuel returning to the tank. • The information is then passed onto the system which applies fuel, ignition and boost corrections. The system allows the driver to add any mixture of ethanol/petrol (from 0-100% ethanol content). Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Apps (3): Recognition of flexible fuel blends • A large number of flexible-fuel vehicles in the US are equipped with an in-line sensor for reading the contents of alcohol in volume • Sensors cost above 100$. • The proposed fiber sensor is capable of recognizing different blends of ethanol-gasoline or methanol-gasoline Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Apps (3): Recognition of flexible fuel blends • Methanol concentration in gasoline: • The sensor readout for each blend is different Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Potential Applications • Identifying flexible fuel blends • Detection of fuel fraud and dilution, at the gas station and inside the car • Monitoring the production of bio-diesel (for example, using methanol and micro-waves) • Monitoring the efficiency of internal combustion process, reduce pollution • Quality control of water, beverages and food • Mobile point-of-care diagnostics (NUFAR program, to begin March 2014). Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014
Conclusion Dr. Avi Zadok, Bar-Ilan Univ. Feb. 2014