654 research outputs found
Sort by
Evanescent wave assisted nanomaterial coating
No full textIn this work we present a novel nanomaterial coating technique using evanescent wave (EW). The gradient force in the EW is used as an optical tweezer for tweezing and self-assembling nanoparticles on the source of EW. As a proof of the concept, we have used a laser coupled etched multimode optical fiber, which generates EW for the EW assisted coating. The section-wise etched multimode optical fiber is horizontally and superficially dipped into a silver/gold nanoparticles solution while the laser is switched on. The fiber is left until the solution recedes due to evaporation leaving the fiber in air. The coating time usually takes 40–50 min at room temperature. The scanning electron microscope image shows uniform and thin coating of self-assembled nanoparticles due to EW around the etched section. A coating thickness <200 nm is achieved. The technique could be useful for making surface-plasmon-resonance-based optical fiber probes and other plasmonic circuits
ZnO@CdS core-shell thin film: fabrication and enhancement of exciton life time by CdS nanoparticle
No full textIn the present study photoluminescence behavior of ZnO and ZnO@CdS core–shell nanorods film has been reported. ZnO nanorods were grown on the glass coated indium tin oxide (ITO) surface by seeding ZnO particle followed with nanorods growth. These nanorods were coated with CdS by chemical bath deposition techniques to have ZnO@CdS thin film and further annealed at 200 °C for their adherence to the ITO surface. The coating was characterized for surface morphology using SEM and optical behavior using UV–visible spectrophotometer. Energy dispersive X-ray (EDX) was used for compositional analysis and time resolve photoluminescence decay for excitons life time measurement. The absorption spectrum reveals that the absorption edge of ZnO@CdS core–shell heterostructure shifted to 480 nm in the visible region whereas ZnO nanorods have absorption maxima at 360 nm. The excitons lifetime of ZnO@CdS was found to be increased with the thickness of the CdS layer on ZnO nanorod. These ZnO@CdS core–shell nanostructures will be of great use in the field of photovoltaic cell and photocatalysis in a UV–visible region
Diffuse reflectance and reflective flexible coatings of capped ZnS nanoparticles
No full textThioglycerol capped ZnS nanoparticles were synthesized by chemical precipitation method and the effect of capping concentration on diffuse reflectance was studied. The comparative study of diffuse reflectance of commercial bulk ZnS particles with synthesised uncapped and capped nanoparticles has been made. ZnS nanoparticles capped with 0.50% of thioglycerol were found to be of uniform shape and size, with maximum diffuse reflectance of 93–94% in the visible region. The reflectors developed using these nanoparticles showed reflectance of 96.5–97.5% in the visible region with optimum coating thickness of 0.25 mm. These reflectors have also been found to be flexibl
Long Period Fiber Grating Humidity Sensor With Gelatin/Cobalt Chloride Coating
No full textA long period fiber grating (LPFG) coated with a combination of cobalt chloride and gelatin is proposed and demonstrated for the monitoring of relative humidity (RH) levels. The thin overlay of the combination and its spectral properties with respect to different ambient humidity levels are observed. Field emission scanning electron microscope and atomic force microscope have provided detailed evidence of attachment of the amalgamation on LPFG surface using adapted coating methodology. The results show a significant shift in the resonance wavelength of the coated LPFG when the RH is varied from 35% to 90%, with a sensitivity of 0.18 nm/% RH and accuracy of 98.55%
Non-invasive Jaundice Detection using Machine Vision
No full textThe study investigated a non-invasive and instant method of jaundice detection using machine vision technique. Color images of sclera region of the eyes of healthy subjects and patients suffering from jaundice were acquired. Image processing algorithms were developed by using CIELab color model. The principal component analysis (PCA)-based discrimination analysis was applied over the color data obtained from patient's sclera region, which showed a variance of 89%. The results of PCA biplot indicated correlations among jaundice patients and color attributes. Based upon these results, neuro-fuzzy-based software was developed for the prediction of jaundice as well as the calculation of degree of its severity. The experimental results show satisfactory performance as compared to the conventional chemical methods. The proposed technique is totally non-invasive and low cost
Novel Design Of Detachable Surgical Tool For Robotic Assisted Minimal Invasive Surgery
No full textIn modern surgical operation, a surgeon using a robotic surgical system which use a manipulator (a variety of surgical instruments, such as tissue graspers, needle drivers), Each of these structures perform functions for the surgeon such as holding or driving a needle, grasping a blood vessel, cutting or dissecting tissue, for this hand input devices of the surgeon's workstation coupled to the surgical instrument by a servo mechanism (more especially DC servo motors). This servo mechanism provides an interfacing between surgeon's hand input and manipulator surgical tool. The surgeon or assistant will mount robotic surgical instruments having suitable end effectors (grasper forceps, scissors, needle etc.) to the manipulator, and will often pass the end effectors through hollow sleeve for internal surgical site, so as to treat the targeted tissues while minimizing injury to the adjacent tissue structures. We are developing surgical tool with minimally invasive robotic surgical system. To use those tools in surgery, the mechanism of system needs to be simple and durable to reduce the cost of robotic surgery. In this paper, we present mechanism for minimally invasive surgical robot tools that have simple structure, easy to manufacture and control. Through an extensive design process, a compact and dexterous robotic surgical manipulator as well as the supporting control hardware is formed
Aqueous synthesis of L-cysteine stabilized water dispersible CdS:Mn quantum dots for biosensing applications
No full textThe present work reports the aqueous synthesis of l-cysteine (2-amino 3-mercaptopropionic acid) capped manganese-doped cadmium sulphide quantum dots (QDs). l-Cysteine functions both as a sulfur source and the stabilizer during the synthesis. The product collected at different time intervals during the reaction showed red shifts in their absorption onsets (peak shifts 380 → 395 → 420 nm) and respective emission (peak shifts 585 → 610 → 660 nm) onsets. Nanoparticles of the average size of 3 ± 0.5 nm were obtained. Based on the theoretical calculations, the maximum band gap energy of the synthesized nanocrystals is found to be 2.83 eV. Fourier transform infrared and Raman spectroscopic studies have confirmed the presence of carboxylic and amine functional groups. Atomic force and electron microscopic techniques have verified the formation of the nanosized QDs. Energy dispersive X-ray spectrometry has confirmed the doping of manganese in the CdS structure, while X-ray diffractometry established the crystal structure as of zinc blend type. The proposed l-cysteine capped CdS:Mn QDs can be termed as multifunctional crystals, which are useful for the assembly of fluorescent molecular probes for clinical analysis and disease diagnosis. The proposed nanocrystals can also be potentially used as contrast agents in the magnetic resonance imaging due to the presence of manganese
Power Management in a Standalone Solar/ Fuel cell/ Battery Hybrid Power system
No full textThis paper explains the design of a standalone Solar/ Fuel cell/ Battery hybrid power system which involves the design of individual systems along with the power management circuit. The variation of solar insolation according to the time and the Maximum Power Point Tracking’s (MPPT) Perturb and Observe (P&O)algorithm is considered in the design of solar system. Similarly, the control of fuel flow rate according to the load and a DC- DC converter is considered in the design of the fuel cell system. A battery charger is designed to protect the battery from the over and under charging from source and load respectively. All these power sources are controlled by the power management circuit, controlling the relays of each subsystem according to the load demand
Human opinion dynamics: An inspiration to solve complex optimization problems
No full textHuman interactions give rise to the formation of different kinds of opinions in a society. The study of formations and dynamics of opinions has been one of the most important areas in social physics. The opinion dynamics and associated social structure leads to decision making or so called opinion consensus. Opinion formation is a process of collective intelligence evolving from the integrative tendencies of social influence with the disintegrative effects of individualisation, and therefore could be exploited for developing search strategies. Here, we demonstrate that human opinion dynamics can be utilised to solve complex mathematical optimization problems. The results have been compared with a standard algorithm inspired from bird flocking behaviour and the comparison proves the efficacy of the proposed approach in general. Our investigation may open new avenues towards understanding the collective decision making
One step electrochemical synthesis of goldnanoparticles– polypyrrole composite for application in catechin electrochemical biosensor
No full textAn electrochemical biosensor has been fabricated for catechin detection using the nanoparticle–polymer composite as a matrix. The composite has been electrochemically synthesized and tyrosinase enzyme was entrapped during polymerization of the composite material. The composite has been characterized for its morphology, optical, structural, and electrochemical behavior. Studies revealed that the presence of gold nanoparticles (AuNPs) in the polymer matrix resulted in an increase in conductivity, enhanced current intensity and diffusion coefficient. The AuNPs–PPy composite provided large surface area for enzyme immobilization and facilitated electron transfer, evident from almost 10% enhancement in biosensor response in the presence of nanoparticles (NPs). For catechin detection, the biosensor showed well defined redox peaks at 0.24 V/0.14 V for the redox reaction of the hydroxyl group present in the catechol moiety of the catechin and a weak oxidation peak at 0.62 V corresponding to the oxidation of the hydroxyl group present in the central ring of catechin. The linearity was achieved from 1 × 10−9 M to 1 × 10−8 M, with a sensitivity of 6.8 × 10−5 A M−1. The limit of detection (3 × SD/sensitivity) and Km value are 1.2 × 10−9 M and 4.5 × 10−9 M respectively. The response time of the biosensor was about 10–12 s with an optimum pH at 7.0. The biosensor has been tested for catechin detection in water and apple juices and the response was within 10% error