Gandhinagar, India
Gandhinagar, India

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Dutta P.,Indian Institute of Plasma | Rastogi N.,Indian Institute of Plasma | Gotewal K.K.,Indian Institute of Plasma
Fusion Engineering and Design | Year: 2017

A tokamak is a plasma confinement device that can be used to achieve magnetically confined nuclear fusion within a reactor. Owing to the harsh environment, Remote Handling (RH) systems are used for inspection and maintenance of the tokamak in-vessel components. As the number of in-vessel components requiring RH maintenance is large, physical prototyping of all strategies becomes a major challenge. The operation of RH systems poses further challenge as all equipment have to be controlled remotely within very strict accuracy limits with minimum reliance on the available camera feedback. In both design and operation phases of RH equipment, application of Virtual Reality (VR) becomes imperative. The scope of this paper is to introduce some applications of VR in the design and operation cycle of RH, which are not available commercially. The paper discusses the requirement of VR as a tool for RH equipment design and operation. The details of a comprehensive VR facility that has been established to support the RH development for Indian tokamaks are also presented. Further, various cases studies are provided to highlight the utilization of this VR facility within phases of RH development and operation. © 2017 Elsevier B.V.

Hussain A.A.,Indian Institute of Plasma | Pal A.R.,Indian Institute of Plasma
Journal of Materials Chemistry C | Year: 2017

We report a conceptually new approach for preparing a ternary blend of polymer/small molecule/metal oxide using plasma nanotechnology and realized it in the fabrication of a high-performance self-powered broadband photodetector. Here, we demonstrate the Förster resonance energy transfer (FRET) effect in a polymer-small molecule system with the incorporation of rubrene, a small molecule. The high absorption of rubrene in the visible region expands the spectral absorption and assists in developing nano-morphology for enhanced charge transport. The polymer absorbs in the UV region and non-radiatively transfers the absorbed energy to rubrene by FRET effect. The time-resolved photoluminescence study reveals efficient excitation energy transfer from the polymer to the small molecule occurring on a nanosecond timescale, thereby confirming the occurrence of FRET. We also demonstrate the synergistic effect of FRET and energy cascade dominated mechanisms when used in the ternary structure (polymer/small molecule/metal oxide) to realize high-performance broadband self-powered photodetector with a very low dark current of 32 pA cm−2 and a high photoconductive gain of 24.34 at zero bias. Conclusively, this configuration has the potential to be directly utilized in traditional multiple donor/acceptor systems with separate spectral responses to work synergistically, thereby allowing an enhancement in both light absorption and photocurrent generation. © The Royal Society of Chemistry.

Dutta P.,Institute of Advanced Study in Science and Technology | Saikia D.,Indian Institute of Plasma | Adhikary N.C.,Indian Institute of Plasma | Sarma N.S.,Institute of Advanced Study in Science and Technology
ACS Applied Materials and Interfaces | Year: 2015

This work reports the development of highly fluorescent materials for the selective and efficient detection of picric acid explosive in the nanomolar range by fluorescence quenching phenomenon. Poly(vinyl alcohol) grafted polyaniline (PPA) and its nanocomposites with 2-mercaptosuccinic acid (MSA)-capped CdTe quantum dots (PPA-Q) and with MSA-capped CdTe/ZnS core/shell quantum dots (PPA-CSQ) are synthesized in a single step free radical polymerization reaction. The thermal stability and photo stability of the polymer increases in the order of PPA < PPA-Q < PPA-CSQ. The polymers show remarkably high selectivity and efficient sensitivity toward picric acid, and the quenching efficiency for PPA-CSQ reaches up to 99%. The detection limits of PPA, PPA-Q, and PPA-CSQ for picric acid are found to be 23, 1.6, and 0.65 nM, respectively, which are remarkably low. The mechanism operating in the quenching phenomenon is proposed to be a combination of a strong inner filter effect and ground state electrostatic interaction between the polymers and picric acid. A portable and cost-effective electronic device for the visual detection of picric acid by the sensory system is successfully fabricated. The device is further employed for quantitative detection of picric acid in real water samples. © 2015 American Chemical Society.

Sharma S.K.,Indian Institute of Plasma | Bailung H.,Indian Institute of Plasma
Physics of Plasmas | Year: 2010

Large amplitude ion acoustic compressive solitary waves are excited in a multicomponent plasma in the presence of a positive ion beam. The threshold amplitude, when steepening of the leading edge of the compressive pulse occurs, depends on the ion beam velocity. The Mach velocity and the amplitude of large amplitude compressive solitary waves are measured for different ion beam velocities. The amplification of the large amplitude compressive solitary wave is observed when the ratio of the ion beam velocity divided by the ion acoustic velocity is in the range of 0.8-1.4. The maximum amplitude of the density perturbation observed in the experiment is quite large (∼170%). © 2010 American Institute of Physics.

Sharma S.K.,Indian Institute of Plasma | Bailung H.,Indian Institute of Plasma
Journal of Geophysical Research: Space Physics | Year: 2013

The evolution of hole Peregrine soliton (appearing as a deep trough between two crests) from ion-acoustic perturbations excited in a multicomponent plasma with critical density of negative ions has been observed. The observed soliton is described by the rational solution of the cubic nonlinear Schrödinger equation, which can appear as an isolated high peak or a deep hole depending on the phase of the underlying carrier wave relative to the envelope. The measured amplitude of the hole Peregrine soliton (depth from crest to trough) is found to be more than twice the background wave height. The experimental observations are compared with the theoretical results obtained from the solution of the cubic nonlinear Schrödinger equation. The frequency spectrum of the Peregrine soliton is analyzed and found to be triangular in shape. © 2013 American Geophysical Union. All Rights Reserved.

Misra S.,Indian Institute of Technology Delhi | Mishra S.K.,Indian Institute of Plasma
Monthly Notices of the Royal Astronomical Society | Year: 2016

In this paper, the flight of micro (μ)-meteoroid in the day time earth environment has been discussed and the role of photoemission due to solar radiation, in addition to other relevant emission processes, viz. thermionic/charge desorption has been explored. Following Mendis et al., the meteoroid flight has been described by a consistent analytical model which manifests the continuity equations for the momentum, energy, charge and mass of micrometeoroids entering in the earth environment with a finite speed and at a finite angle. The altitude profiles of the characteristic features during flight, viz. surface heating, particle size, mass-loss, charging and its consequence on local atmospheric plasma has been examined in terms of the angle of entrance, entry speed, size, material work function/photoefficiency and incident solar flux. The numerical results show that the photoemission from micrometeoroid significantly contributes in meteoric electrons generation in its path in beginning and end phase of the flight; of course the energetics over the meteoroid in its travel is dominated by mass ablation process. © The Authors 2016. Published by Oxford University Press on behalf of The Royal Astronomical Society.

Dutta N.J.,Indian Institute of Plasma | Buzarbaruah N.,Indian Institute of Plasma | Mohanty S.R.,Indian Institute of Plasma
Journal of Nuclear Materials | Year: 2014

Energetic and high fluence helium ions emitted in a plasma focus device have been used successfully to study the radiation induced damage on tungsten. The reference and irradiated samples were characterized by optical microscopy, field emission scanning electron microscopy, X-ray diffraction and by hardness testers. The micrographs of the irradiated samples at lower magnification show uniform mesh of cracks of micrometer width. However at higher magnification, various types of crystalline defects such as voids, pinholes, bubbles, blisters and microcracks are distinctly noticed. The prominent peaks in X-ray diffraction spectrum of irradiated samples are seen shifted toward higher Bragg angles, thus indicating accumulation of compressive stress due to the heat load delivered by helium ions. A marginal reduction in hardness of the irradiated sample is also noticed. © 2014 Elsevier B.V. All rights reserved.

Bailung H.,Indian Institute of Plasma | Sharma S.K.,Indian Institute of Plasma | Nakamura Y.,Indian Institute of Plasma | Nakamura Y.,Yokohama National University
Physical Review Letters | Year: 2011

The experimental observation of Peregrine solitons in a multicomponent plasma with the critical concentration of negative ions is reported. A slowly amplitude modulated perturbation undergoes self-modulation and gives rise to a high amplitude localized pulse. The measured amplitude of the Peregrine soliton is 3 times the nearby carrier wave amplitude, which agrees with the theory. The numerical solution of the nonlinear Schrödinger equation is compared with the experimental results. © 2011 American Physical Society.

Hussain A.A.,Indian Institute of Plasma | Sharma B.,Indian Institute of Plasma | Barman T.,Indian Institute of Plasma | Pal A.R.,Indian Institute of Plasma
ACS Applied Materials and Interfaces | Year: 2016

We report the demonstration of plasmonic titanium nitride (TiN) for fabrication of an efficient hybrid photodetector. A novel synthesis method based on plasma nanotechnology is utilized for producing air stable plasma polymerized aniline-TiN (PPA-TiN) nanocomposite and its integration in photodetector geometry. The device performs as a self-powered detector that responds to ultraviolet and visible light at zero bias. The photodetector has the advantage of broadband absorption and outcomes an enhanced photoresponse including high responsivity and detectivity under low light conditions. This work opens up a new direction for plasmonic TiN-based hybrid nanocomposite and its exploitation in optoelectronic applications including imaging, light-wave communication and wire-free route for artificial vision. © 2016 American Chemical Society.

Chakravarty S.,Institute of Advanced Study in Science and Technology | Saikia D.,Indian Institute of Plasma | Sharma P.,Institute of Advanced Study in Science and Technology | Adhikary N.C.,Indian Institute of Plasma | And 2 more authors.
Analyst | Year: 2014

The development of a rapid, label free, cost effective and highly efficient sensor for DNA detection is of great importance in disease diagnosis. Herein, we have reported a new hybrid fluorescent probe based on a cationic curcumin-tryptophan complex and water soluble mercapto succinic acid (MSA) capped CdTe quantum dots (QDs) for the detection of double stranded DNA (ds DNA) molecules. The cationic curcumin-tryptophan complex (CT) directly interacts with negatively charged MSA capped quantum dots via electrostatic coordination, resulting in photoluminescence (PL) quenching of QDs via the Photoinduced Electron Transfer (PET) process. Further, addition of ds DNA results in restoration of PL, as CT would intercalate between DNA strands. Thus, this process can be utilized for selective sensing of ds DNA via fluorescence measurements. Under optimized experimental conditions, the PL quenching efficiency of QDs is found to be 99.4% in the presence of 0.31 × 10-9 M CT. Interestingly, the regain in PL intensity of QD-CT is found to be 99.28% in the presence of 1 × 10-8 M ds DNA. The detection limit for ds DNA with the developed sensing probe is 1.4 × 10-10 M. Furthermore, the probe is found to be highly sensitive towards bacterial DNA isolated from Streptomyces sanglieri with a detection limit of 1.7 × 10-6 M. The present work will provide a new insight into preparation of bio-inspired hybrid materials as efficient sensors for disease diagnosis and agricultural development. © The Royal Society of Chemistry 2014.

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