The Experts below are selected from a list of 3216 Experts worldwide ranked by ideXlab platform

B D Gupta - One of the best experts on this subject based on the ideXlab platform.

  • theoretical modelling of a bi dimensional u shaped surface plasmon resonance based Fibre Optic Sensor for sensitivity enhancement
    Journal of Physics D, 2008
    Co-Authors: R K Verma, B D Gupta
    Abstract:

    Theoretical analysis of a surface plasmon resonance based Fibre Optic Sensor with a uniform semi-metal coated U-shaped probe is carried out using a bi-dimensional model. All the rays of the p-polarized light launched in the Fibre and their electric vectors are assumed to be confined in the plane of bending of the U-shaped probe. The effect of the bending radius of the probe on the sensitivity of the Sensor is studied. The study shows that as the bending radius of the probe decreases the sensitivity of the Sensor increases. For the light launching conditions used, the maximum sensitivity achieved is several times more than that reported for a Fibre Optic tapered probe. In addition to high sensitivity, the most advantageous feature of a U-shaped probe is that it can be used as a point Sensor.

  • Fibre Optic Sensor based on surface plasmon resonance with ag au alloy nanoparticle films
    Nanotechnology, 2006
    Co-Authors: Anuj K Sharma, B D Gupta
    Abstract:

    The design of a Fibre Optic surface plasmon resonance (SPR) Sensor based on silver–gold alloy nanoparticle film is studied. The performance of the proposed Sensor is theoretically analysed in terms of its signal-to-noise ratio (SNR) and sensitivity under different conditions related to the metal layer with silver and gold nanoparticles embedded together in layers to form a single alloy film. The effects of related parameters such as alloy composition ratio, metal nanoparticle size, and alloy film thickness are studied and the physical reasoning behind the results is given. A logical comparison is carried out between a previously proposed metal-host based Fibre Optic SPR Sensor and the present one. The alloy based Fibre Optic SPR Sensor is shown to have better performance than the metal-host based Fibre Optic SPR Sensor.

Mohammed Zeb Elshafie - One of the best experts on this subject based on the ideXlab platform.

  • robust Fibre Optic Sensor arrays for monitoring early age performance of mass produced concrete sleepers
    Structural Health Monitoring-an International Journal, 2018
    Co-Authors: Liam J Utle, Niamh Gibbons, Sami Dira, C R Middleto, Mohammed Zeb Elshafie
    Abstract:

    © 2017, © The Author(s) 2017. This study investigates integrating Fibre Optic sensing technology into the production process of concrete railway sleepers. Robust Fibre Bragg grating strain and temperature Sensor arrays were developed specifically for this application and were designed for long-term monitoring of sleeper performance. The Sensors were used to monitor sleeper production and to help gain a deeper understanding of their early-age behaviour which can highly influence long-term performance. In total, 12 sleepers were instrumented and strain data were collected during the entire manufacturing process including concrete casting and curing, prestressing strand detensioning and qualification testing. Following the production process, sleepers were stored temporarily and monitored for 4 months until being placed in service. The monitoring results highlight the intrinsic variability in strain development among identical sleepers, despite high levels of production quality control. Using prestress loss as a quality control indicator, the integrated sensing system demonstrated that sleepers were performing within Eurocode-based design limits prior to being placed in service. A three-dimensional nonlinear finite element model was developed to provide additional insight into the sleepers’ early-age behaviour. Based on the Fibre Bragg grating–calibrated finite element model, more realistic estimates for the creep coefficient were provided and found to be 48% of the Eurocode-predicted values.

Anuj K Sharma - One of the best experts on this subject based on the ideXlab platform.

  • on the performance of surface plasmon resonance based Fibre Optic Sensor with different bimetallic nanoparticle alloy combinations
    Journal of Physics D, 2008
    Co-Authors: Anuj K Sharma, Gerhard J Mohr
    Abstract:

    In this work, we have investigated the capability of different bimetallic nanoparticle alloy combinations to be used in Fibre Optic Sensors based on the technique of surface plasmon resonance. The metals considered for this analysis are silver, gold, copper and aluminium. The performance of the Sensor with different bimetallic nanoparticle alloy combinations is evaluated and compared numerically. The performance is analysed in terms of three parameters: sensitivity, signal-to-noise ratio (SNR) and operating range for the sensing layer refractive index values. On the basis of the comparison and some logistic criteria, the best possible bimetallic alloy combinations along with a requisite alloy composition ratio are predicted. The bimetallic nanoparticle alloy combination is capable of simultaneously providing larger values of sensitivity, SNR and operating range, which is not possible with any single metallic nanoparticle layer.

  • Fibre Optic Sensor based on surface plasmon resonance with ag au alloy nanoparticle films
    Nanotechnology, 2006
    Co-Authors: Anuj K Sharma, B D Gupta
    Abstract:

    The design of a Fibre Optic surface plasmon resonance (SPR) Sensor based on silver–gold alloy nanoparticle film is studied. The performance of the proposed Sensor is theoretically analysed in terms of its signal-to-noise ratio (SNR) and sensitivity under different conditions related to the metal layer with silver and gold nanoparticles embedded together in layers to form a single alloy film. The effects of related parameters such as alloy composition ratio, metal nanoparticle size, and alloy film thickness are studied and the physical reasoning behind the results is given. A logical comparison is carried out between a previously proposed metal-host based Fibre Optic SPR Sensor and the present one. The alloy based Fibre Optic SPR Sensor is shown to have better performance than the metal-host based Fibre Optic SPR Sensor.

Sergiy Korposh - One of the best experts on this subject based on the ideXlab platform.

  • Carboxyl-fentanyl detection using Optical Fibre grating-based Sensors functionalised with molecularly imprinted nanoparticles
    2021
    Co-Authors: Liangliang Liu, Andrew Norris, Ricardo Correia, Stephen P Morgan, Fabiana Grillo, Francesco Canfarotta, Michael Whitcombe, Sergey Piletsky, Sergiy Korposh
    Abstract:

    Butyrylfentanyl is a new designer drug reported with growing use and related deaths. Routine toxicological analyses of this novel synthetic opioid drug have not been established yet. This work reports a Fibre Optic Sensor that measures carboxyl-fentanyl which is the major metabolite of butyrylfentanyl presented in blood, providing a promising tool for detecting butyrylfentanyl intoxication. A long period Fibre grating (LPG) Sensor array operating at phase-matching condition is deployed in combination with a state-of-the-art molecular imprinting technique. Nano-sized molecularly imprinted polymers (nanoMIPs) are synthesised via a solid-phase approach and coated on the surface of an LPG array. An LPG array consists of two parts: a detection and a reference LPG. The former is functionalised with nanoMIPs prior to the measurements, whilst the latter is used to take into account the temperature response of the detection LPG. The developed Sensor exhibits a gradual response over increasing concentrations of carboxyl-fentanyl from 0 to 1000 ng/mL with a minimal detected concentration of 50 ng/mL, that corresponds to a wavelength shift of 1.20 ± 0.2 nm. The Langmuir adsorption isotherm is applied to fit the analytical data which reveal a binding constant of 2.03 μM-1. The developed Sensor shows high selectivity in detecting carboxyl-fentanyl among other drugs and potential interferents including morphine, cocaine, glucose and albumin. It shows a certain degree of cross-response to fentanyl which shares the same binding sites as carboxyl-fentanyl and therefore can be potentially used to detect fentanyl

  • A reflection-mode Fibre-Optic Sensor for breath carbon dioxide measurement in healthcare
    Elsevier, 2019
    Co-Authors: Liangliang Liu, Fenghuan Hao, Andrew Norris, Ricardo Correia, Stephen P Morgan, Sergiy Korposh
    Abstract:

    A reflection-mode carbon dioxide (CO2) Fibre Optic Sensor (FOS) is developed based on the colorimetric change of pH indicator dye thymol blue. The CO2 sensing film comprises thymol blue and tetramethylammonium hydroxide in the form of an ion pair doped in an organically modified silica film. A dip coating process was conducted to coat the sensing film on the tip of Optical Fibre with a film thickness approximately 2.7 ± 0.1 μm. The observed reflection signal at a wavelength of 608 nm exhibits a reversible change for the concentration of CO2 range from 0 to 6% with a response time of 19 s and recovery time of 170 s for 6% of CO2. An optimal concentration of thymol blue in the preparation of coating solution that provides a highest sensitivity was found to be 2.9 mg/ml. Storing the FOS in a pure nitrogen atmosphere provided a stable film with a shelf-life of over 15 days as compared to a gradual degradation in film performance and complete loss of sensitivity after 10 days with storage in ambient air. The FOS response is affected by relative humidity (RH) and a humidity filter was demonstrated to reduce humidity levels in breath from 90% to 40–50% to reduce this effect. The developed FOS was used to measure the end-tidal breath CO2 for testing its applicability in healthcare. The CO2 measurement from breath sample using our FOS shows a good agreement (percentage error~3%) with a commercial CO2 datalogger (K-33 BLG, CO2 Meter, USA). Due to the limitation of response time, at present the FOS is limited to measuring variation of the CO2 from slow breath to breath. Keywords: Optical Fibre CO2 Sensor, Colorimetric change, pH indicator, Thymol blue, Sol-gel, End-tidal CO

  • Highly sensitive ethanol vapour measurements using a Fibre Optic Sensor coated with metal organic framework ZIF-8
    2017 IEEE SENSORS, 2017
    Co-Authors: Jiri Hromadka, Begum Tokay, Ricardo Correia, Stephen P Morgan, Sergiy Korposh
    Abstract:

    An Optical Fibre long period grating (LPG) based volatile organic compound (VOC) Sensor coated with ZIF-8, a material from the zeolite imidazolate framework (ZIF) family, functional coating is presented. ZIF-8 film was deposited onto the surface of the LPG using an in-situ crystallization technique. A concentration specific response to ethanol was obtained over the range from 62 to 666 ppm. A novel approach for the data analysis based on the measurement of the bandwidth of the U-shaped attenuation band of the LPG is introduced. The Sensor shows a sensitivity of 0.018±0.0015 nm/ppm and limit of detection (LOD) of 5.56 ppm for ethanol vapour in air.

  • Identification and quality assessment of beverages using a long period grating Fibre-Optic Sensor modified with a mesoporous thin film
    Elsevier, 2014
    Co-Authors: Sergiy Korposh, Roman Selyanchyn, Stephen James, Ralph Tatam, Seung-woo Lee
    Abstract:

    In this study, an Optical Fibre long period grating (LPG) Sensor functionalised with a mesoporous thin film was employed for the identification and quality assessment of beverages. The principle of the discrimination of beverages using an LPG Sensor is based on the measurement of the change in refractive index of a sensitive film, induced by the binding of the chemical compounds present in the beverage. The sensitive film deposited onto the LPG consisted of poly(allylamine hydrochloride) (PAH) and silica nanospheres (SiO2 NPs) with diameters ranging from 40 nm to 50 nm. PAH imparts selectivity, while the SiO2 NPs endow the film with high porosity and enhanced sensitivity. In this study, five different types of beverages, red and white wines, brandy, nihonshyu (sake, a Japanese rice wine), and shochu (a Japanese distilled beverage), prepared via distillation and fermentation, were used to assess the capability of the Sensor to identify the origin of the beverages. In addition, a selection of red wines was used to evaluate the use of the Sensor in the assessment of the quality of beverages. The results obtained were benchmarked against those obtained using gas chromatography–mass spectrometry for the determination of volatile compounds contributing to the flavours of a set of red wines. Principal component analysis (PCA) was employed for data analysis. This approach enabled both quality assessment of beverages and identification of the methods and materials used for their preparation. Keywords: Long period grating, Mesoporous thin film, Layer-by-layer, Quality assessment, Beverage

Gerard Franklyn Fernando - One of the best experts on this subject based on the ideXlab platform.

  • Process monitoring of Fibre reinforced composites using a multi-measurand Fibre-Optic Sensor
    Sensors and Actuators B: Chemical, 2015
    Co-Authors: Abilash K. Nair, Corinne Barrow, R.s. Mahendran, S. D. Pandita, Christophe Paget, Venkata Rajanikanth Machavaram, Gerard Franklyn Fernando
    Abstract:

    This paper reports on the design, fabrication, characterisation and deployment of a multi-measurand Optical Fibre Sensor (MMS) that is capable of simultaneously monitoring strain, temperature, refractive index and cross-linking chemistry. The Sensor design is based on the extrinsic Fibre Fabry-Perot interferometer. A feature of this Sensor system is that a conventional multi-channel Fibre-coupled near-infrared spectrometer is used to monitor the four independent parameters. The issues relating to the measurement resolution of the individual Sensors and the associated interrogation equipment are discussed. The MMS was embedded in between the fourth and fifth plies of an eight-ply E-glass plain-weave fabric. A commercially available thermosetting epoxy/amine resin system was used to impregnate the fabric layers manually. The laminated preform was vacuum-bagged and cured in an autoclave. The following parameters were monitored: the depletion rates of the epoxy and amine functional groups in the resin system; the temperature in close proximity to the "chemical Sensor"; the evolution of strain; and the refractive index of the resin system. The effect of post-processing on the output from the embedded Optical Fibre Sensors is also considered.

  • Structural health monitoring of smart civil structures using Fibre Optic Sensors
    2005
    Co-Authors: J. S. Leng, R.a. Barnes, G. C. Mays, Gerard Franklyn Fernando
    Abstract:

    A number of embedded Sensor protection system (ESPS) and surface-mountable Sensor protection system (SSPS) for Fibre Optic Sensor (FOS) have been developed in this paper. Fibre Bragg Grating (FBG) and Extrinsic Fabry-Perot interferometric (EFPI) Sensors protected by the designed protections system have been used to monitor the cure progress and structural health status of concrete cylinders. Results indicate that the Sensor protection systems for the FOS perform adequately and effectively in concrete environment. The protected Fibre Optic Sensors are suitable achieve the structural health monitoring in practical. It is also revealed that there is excellent correlation between the results obtained from the protected FOS and reference electrical resistance strain gauges.