Dessiign and Devellopmentt off FFiiberr Opttiicc Senssorrss fforr Qualliitty Evalluattiion off varriiouss LLiiquiid and Gasseouss Mediia

Cochin University of Science And Technolog

Invariance Improved Legendre Moments As Contour-Shape Descriptor

A new shape descriptor based on improved Legendre moments, invariant to affine transformations and suitable as both contour and region-shape descriptor is proposed in this paper. The objective performance comparison of the improved Legendre descriptor with modified Zernike descriptor was carried out. The Average normalized modified retrieval rank (ANMRR) obtained on SQUID database for improved Legendre descriptor was 0.1673, and for modified Zernike descriptor was 0.3514, which depicts the better accuracy of the proposed technique. The subjective evaluation of the retrieval results of Legendre and Zernike descriptor also shows the better performance of the Legendre descriptor

Fiber Optic Long Period Grating Based Sensor for Coconut Oil Adulteration Detection

We report the development and demonstration of a Long-Period Grating (LPG) based optical fiber sensor for determining the adulteration of coconut oil by palm oil. The fundamental principle of detection is the sensitive dependence of the resonance peaks of LPG on the changes of the refractive index of the environmental medium around the cladding surface of the grating. Refractive index sensing with LPGs employs light coupling between core and cladding modes in the grating section. The transmittance spectra of a long period grating element immersed in different mixtures of coconut oil and palm oil were recorded. Results show that resonance wavelengths and transmission intensities varied as a function of the adulteration level of coconut oil. Detection limit of adulteration was found to be 2 % for coconut oil–palm oil binary mixture

Detection and analysis of paraffin oil adulteration in coconut oil using fiber optic long period grating sensor

A fiber optic sensing system for the detection of adulteration of coconut oil by paraffin oil is experimentally demonstrated. The sensing mechanism is based on the sensitive dependence of the resonance peaks of a long period grating (LPG) on the changes of the refractive index of the environmental medium surrounding the cladding surface of the grating. The wavelength shift of the attenuation bands of the LPG was measured with the sensor immersed in a mixture of paraffin oil and pure coconut oil in different proportions. Detection limit of adulteration was found to be 3% for coconut oil paraffin oil binary mixture. (C) 2010 Elsevier GmbH. All rights reserved

The effect of grating period on refractive index sensitivity of long period gratings written in hydrogen loaded SMF-28 fiber

In this paper, the influence of grating period of Long Period Grating (LPG) on refractive index sensitivity is experimentally investigated. Two LPGs with grating periods 415 mu m and 550 mu m are used to carry out the experimental study. The fundamental principle of analysis is the sensitive dependence of the resonance peaks of an LPG on the changes in the refractive index of the medium surrounding the cladding surface of the grating. The response of the LPG to refractive indices greater than and less than that of cladding is studied by monitoring the wave length shift and amplitude changes of the attenuation bands

Fiber optic sensor for the adulteration detection of edible oils

A fiber optic sensing system for the adulteration detection of coconut oil and sunflower oil by less expensive paraffin oil is presented. The fundamental principle of detection is the sensitive dependence of the resonance peaks of a Long Period Grating (LPG) on the changes in the refractive index of the environmental medium, surrounding the cladding surface of the grating. The spectral changes in the grating response due to variation of adulteration levels have been investigated. Detection limit of adulteration was found to be 3% for coconut oil- paraffin oil binary mixture and 4 A for sunflower oil-paraffin oil binary mixture

Periodically Tapered LPFG for Ethanol Concentration Detection in Ethanol-Gasoline Blend

In this paper we report the fabrication of periodically tapered Long Period Fiber Grating (LPFG) in standard single-mode telecommunication fiber using electric arc from a fusion splicer. The ability of the fusion splicer to precisely taper the fiber is effectively utilized for producing periodic tapers in the fiber. The antisymmetric resonant mode of the fabricated LPFG is utilized as a refractive index transducer to measure the ethanol concentration in ethanol-gasoline blends. The work carried out shows that compared with the normal arc induced LPFG, the periodically tapered one shows better refractive index sensitivity

Glucose Concentration Sensor Based on Long Period Grating Fabricated from Hydrogen Loaded Photosensitive Fiber

A fiber optic sensing system for the concentration measurement of glucose in distilled water is presented. The fundamental principle of detection is the sensitive dependence of the resonance peaks of a Long Period Grating (LPG) on the changes in the refractive index of the environmental medium, surrounding the cladding surface of the grating. The performance of the sensor has been tested by, monitoring wave length shift and amplitude changes of the attenuation bands of the LPG in response to variation of glucose concentration levels. The developed sensor is user-friendly, reusable and allows instantaneous determination of the glucose concentration without involving any reagents

A Biosensor for the Detection and Estimation of Cholesterol Levels based on Long Period Gratings

A Fiber Optic sensor for determining the total cholesterol has been designed and developed. The Long Period Grating (LPG) sensor developed showed good stability and repeatable performance. The sensor also showed good linear response in the range of 500 ppm to 4000 ppm of cholesterol levels. This is highly desirable for a commercial cholesterol sensor as the level of cholesterol for normal humans ranges from 1400 ppm to 2000 ppm

The effect of annealing and temperature on transmission spectra of long period gratings written in hydrogen loaded standard single mode fiber

The influence of annealing and temperature on the transmission spectrum of Long Period Grating (LPG) is investigated by monitoring the wavelength shift and the intensity variation in the loss peaks. The LPGs are inscribed in a hydrogen loaded standard telecommunication fiber and experiments are performed at different annealing temperature and time to observe the spectral changes. The effect of temperature changes on the spectral profile of LPG is also studied. (c) 2013 Elsevier GmbH. All rights reserved