Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

In this paper, we report on the comprehensive study on Molybdenum disulfide (MoS2) nanolayer coated etched Fiber Bragg Grating (eFBG) strain sensor. MoS2 nanolayer is coated using Physical Vapor Deposition (PVD) of Molybdenum (Mo) on eFBGs followed by sulfurization of the same in an inert atmosphere at 450° C. Such coating technique provides a direct control over the coating thickness of MoS2, thereby enabling a study based on the effect of nanolayer coating thickness on the intrinsic strain sensitivity as well as the power of the back reflected Bragg wavelength of eFBG in the 0.78eV spectral region. High uniformity of MoS2 nanolayer coating ensures consistent, repeatable and highly linear FBG strain sensors with a correlation coefficient of 0.988 in the range of 0 to $2500~\mu \varepsilon $. A maximum intrinsic strain sensitivity of 6.65 pm/ $\mu \varepsilon $ with a resolution of $\sim 150~\text{n}\varepsilon $ have been achieved with optimized MoS2 coated eFBG sensors. This kind of consistent, highly sensitive and linear strain sensors when incorporated with proper packaging schemes can be particularly useful for applications demanding high sensitivity of FBG sensors such detection of seismic vibrations, underwater acoustic signals, low amplitude accelerations, etc. © 2001-2012 IEEE.

Department of Mathematics

School of Advanced Sciences

Vellore Campus

World University root node

Fulltext

IEEE Sensors Journal

A Study on MoS Nanolayer Coated Etched Fiber Bragg Grating Strain Sensor

The real-time, continuous, beat-to-beat blood pressure (BP) monitoring is vital in clinical scenarios such as operations theatres, ambulances etc. In the present study, a non-invasive BP monitoring methodology based on Fiber Bragg Grating sensors is reported. The design and development of Fiber Bragg Grating based Pulse Monitoring Device (FBGPM) is demonstrated which is capable of acquiring the radial arterial pulse pressure waveform effectively in real time. The Radial Arterial Pulse Pressure Waveform is acquired on beat to beat basis employing developed FBGPM in a clinical environment. Further, the recorded radial arterial pulse pressure waveform is processed to obtain systolic and diastolic BP by utilizing a standard non-invasive BP measurement device as a reference. The BP values obtained through FBGPM are then compared with the BP values obtained through an Intra-Arterial (IA) probe. The FBGPM is a chemically and electrically inert device which makes it an effective candidate for monitoring the real-time BP. The focus of the study is to demonstrate the feasibility of deploying developed FBGPM device in clinical environment to acquire beat-to-beat BP and subsequently compare the present device to the IA probe method of BP acquisition. © 2001-2012 IEEE.

Fiber Bragg Grating-Based Pulse Monitoring Device for Real-Time Non-Invasive Blood Pressure Measurement - A Feasibility Study

The development of an etched fiber Bragg grating (eFBG)-based temperature sensor with a uniform multi-layer molybdenum-di-sulphide (MoS2) coating is presented in this paper. Multi-layer MoS2 has been coated on clad etched FBG sensors by DC magnetron sputtering of molybdenum (Mo) and subsequent sulfurization. The dependence of temperature sensitivity on the coating thickness of MoS2 on eFBGs has been tested from room temperature to 100°C. It has been found that MoS2 coated clad etched FBG sensors with a coating thickness of around 10 nm exhibit a maximum temperature sensitivity of ∼95 pm∕°C (almost one order higher than that of bare fiber Bragg gratings), with a resolution of ∼0.01°C obtained using an FBG interrogator with 1 pm resolution. © 2019 Optical Society of America.

Applied Optics

Temperature sensor based on multi-layer MoS2 coated etched fiber Bragg grating

In this work, an analysis of pressure response of a fiber Bragg grating (FBG) sensor in a side-hole package is presented using the finite element method. Various parameters of the side-hole packaging such as hole radius, the distance of separation between them, the radius and length of the package, and the choice of the package material are considered and optimized in order to promote maximum pressure sensitivity of the FBG sensor. This investigation on optimization of the side-hole package parameters gives rise to pressure sensitivity of nearly 105 times as compared with the bare FBG sensor, with the numerical values of 3 pm/MPa for a bare FBG sensor to ∼280,000 pm∕MPa for an optimized side-hole package FBG sensor. Such high-pressure sensitivity of an FBG sensor is being reported for the very first time in this work, to the best of our knowledge, and can be considered as the initial step toward the realization of a highly sensitive hydrophone based on FBG for sensing underwater acoustic signals. © 2018 Optical Society of America.

Highly sensitive fiber Bragg grating-based pressure sensor using side-hole packaging

We demonstrate side-hole packaged; nanolayer Molybdenum (Mo) coated etched Fiber Bragg Grating (eFBG) as hydrostatic pressure sensor. Pressure sensitivity enhancement of nearly 2000 times is observed with such a simple, ruggedized and packaged sensor system. © 2019 OSA.

2019 Conference on Lasers and Electro-Optics, CLEO 2019 - Proceedings

Hydrostatic Pressure Response of Mo Coated Etched Fiber Bragg Grating Sensor in Side-Hole Packaging

This paper demonstrates multilayer Molybdenum disulfide (MoS 2 ) coated etched Fiber Bragg Grating (eFBG) as highly sensitive hydrophone. Multilayer coating of MoS 2 on eFBG is achieved using sputtering of Molybdenum (Mo) followed by sulfurization at 450°C in an inert gas atmosphere. MoS 2 coated eFBG subjected to underwater acoustic pressure showed an increase in pressure sensitivity of nearly 20 times at 231Hz in comparison with bare FBG sensors. © 2018 IEEE.

Proceedings of IEEE Sensors

Multilayer MoS 2 Coated Etched Fiber Bragg Grating Based Hydrophone

Mechanical behavior of three-dimensional cellular assembly of graphene foam (GF) presented temperature dependent characteristics evaluated at both low temperature and room temperature conditions. Cellular structure of GF comprised of polydimethyl siloxane polymer as a flexible supporting material demonstrated 94% enhancement in the storage modulus as compared to polymer foam alone. Evaluation of frequency dependence revealed an increase in both storage modulus and tan delta with the increase in frequency. Moreover, strain rate independent highly reversible behavior is measured up to several compression cycles at larger strains. It is elucidated that the interaction between graphene and polymer plays a crucial role in thermo-mechanical stability of the cellular structure. © 2015 Elsevier Ltd.

Carbon

Temperature dependent compressive behavior of graphene mediated three-dimensional cellular assembly

Growth of highly dense ZnO nanowires (ZnO NWs) is demonstrated on three-dimensional graphene foam (GF) using resistive thermal evaporation technique. Photoresponse of the as-grown hybrid structure of ZnO NWs on GF (ZnO NWs/GF) is evaluated for ultraviolet (UV) detection. Excellent photoresponse with fast response and recovery times of 9.5 and 38 s with external quantum efficiency of 2490.8% is demonstrated at low illumination power density of 1.3 mW/cm2. In addition, due to excellent charge carrier transport, mobility of graphene reduces the recombination rate of photogenerated charge carriers, hence the lifetime of photogenerated free charge carriers enhances in the photodetectors. © 2015 American Chemical Society.

ACS Applied Materials and Interfaces

Highly dense ZnO nanowires grown on graphene foam for ultraviolet photodetection

The objective of this paper is to compare in silico data with wet lab physicochemical properties of crude laccase enzyme isolated from Rigidoporus sp. using wheat bran as solid substrate support towards dye decolorization. Molecular docking analysis of selected nine textile and non-textile dyes were performed using laccase from Rigidoporus lignosus as reference protein. Enzyme-based remediation methodology using crude enzyme enriched from solid state fermentation was applied to screen the effect of four influencing variables such as pH, temperature, dye concentration, and incubation time toward dye decolorization. The extracellular crude enzyme decolorized 69.8 % Acid Blue 113, 45.07 % Reactive Blue 19, 36.61 % Reactive Orange 122, 30.55 % Acid Red 88, 24.59 % Direct Blue 14, 18.48 % Reactive Black B, 16.49 % Reactive Blue RGB, and 11.66 % Acid Blue 9 at 100 mg/l dye concentration at their optimal pH at room temperature under static and dark conditions after 1 h of incubation without addition of any externally added mediators. Our wet lab studies approach, barring other factors, validate in silico for screening and ranking textile dyes based on their proximity to the T1 site. We are reporting for the first time a combinatorial approach involving in silico methods and wet lab-based crude laccase-mediated dye decolorization without any external mediators. © Springer Science+Business Media New York 2013.

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

Applied Biochemistry and Biotechnology

In Silico and in Vitro Physicochemical Screening of Rigidoporus sp. Crude Laccase-assisted Decolorization of Synthetic Dyes—Approaches for a Cost-effective Enzyme-based Remediation Methodology

In this work, an analysis of pressure response of a fiber Bragg grating (FBG) sensor in a side-hole package is presented using the finite element method. Various parameters of the side-hole packaging such as hole radius, the distance of separation between them, the radius and length of the package, and the choice of the package material are considered and optimized in order to promote maximum pressure sensitivity of the FBG sensor. This investigation on optimization of the side-hole package parameters gives rise to pressure sensitivity of nearly 105<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"><mrow><msup><mrow><mn>10</mn></mrow><mrow><mn>5</mn></mrow></msup></mrow></math>&nbsp;times as compared with the bare FBG sensor, with the numerical values of 3&nbsp;pm/MPa for a bare FBG sensor to ∼280,000  pm/MPa<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline" id="m2"><mrow><mo form="prefix" lspace="0em" rspace="0em">∼</mo><mn>280,000</mn><mtext> </mtext><mtext> </mtext><mi>pm</mi><mo>/</mo><mi>MPa</mi></mrow></math>&nbsp;for an optimized side-hole package FBG sensor. Such high-pressure sensitivity of an FBG sensor is being reported for the very first time in this work, to the best of our knowledge, and can be considered as the initial step toward the realization of a highly sensitive hydrophone based on FBG for sensing underwater acoustic signals.