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Muthuchamy A.,Vellore Institute of Technology | Raja Annamalai A.,Vellore Institute of Technology | Agrawal D.K.,Pennsylvania State University | Upadhyaya A.,IIT KanpurUP
Materials Characterization | Year: 2016

The present study examines the effect of sintering temperature and heating mode on densification, microstructure and mechanical properties of Fe-P alloys. The green compacts were heated conventionally and in microwave under 95%N2-5%H2 (forming gas) at 1120 °C and 1250 °C for 60 min. Both the compositions (Fe-1.5P and Fe-3P in wt%) were found to couple well in microwave field with rapid heating (∼ 40 °C min-1) and resulted in reduction of overall processing time by about 90% in comparison of conventional heating. Microwave sintering resulted in higher densification in case of Fe-P alloys. Moreover, an important feature of microwave and conventionally sintered samples was that their microstructures exhibited distinctly rounded pores. This resulted into improved corrosion and mechanical properties in general. © 2016 Elsevier Inc. All rights reserved. Source

Bhandary D.,IIT KanpurUP | Benkova Z.,University of Porto | Benkova Z.,Slovak Academy of Sciences | Cordeiro M.N.D.S.,University of Porto | Singh J.K.,IIT KanpurUP
Soft Matter | Year: 2016

In this work, the effect of temperature on the contact angle of a water droplet on grafted thermo-responsive poly-(N-isopropylacrylamide) (PNIPAAm) polymer brushes is studied using all-atom molecular dynamics simulations in the temperature range of 270-330 K. A shift from 55°to 65°in contact angle values is observed as the temperature increases from 300 K to 310 K, which is in line with the experimental reports. The behavior of a water droplet on PNIPAAm brushes is analyzed using hydrogen bond analysis, water diffusion, radial distribution functions, the potential of mean force, excess entropy and the second virial coefficient (B2). The thermo-responsive behavior of PNIPAAm brushes, quantified using the excess entropy and B2 of PNIPAAm-water and water-water interactions, is mainly governed by polymer-water interactions. In particular, the excess entropy and B2 of PNIPAAm resulting from the PNIPAAm-water interactions are found to increase with increasing temperature. The dehydration of PNIPAAm brushes and the increase in the contact angle of water were confirmed to be entropy driven processes. © The Royal Society of Chemistry 2016. Source

Gupta H.,IIT KanpurUP | Rathor S.K.,IIT KanpurUP | Pessah M.E.,Niels Bohr Institute | Chakraborty S.,IIT KanpurUP | Chakraborty S.,Mechanics and Applied Mathematics Group
Physics Letters, Section A: General, Atomic and Solid State Physics | Year: 2016

We use the machinery usually employed for studying the onset of Rayleigh-Bénard convection in hydro- and magnetohydro-dynamic settings to address the onset of convection induced by the magnetothermal instability and the heat-flux-buoyancy-driven-instability in the weakly-collisional magnetized plasma permeating the intracluster medium. Since most of the related numerical simulations consider the plasma being bounded between two 'plates' on which boundary conditions are specified, our strategy provides a framework that could enable a more direct connection between analytical and numerical studies. We derive the conditions for the onset of these instabilities considering the effects of induced magnetic tension resulting from a finite plasma beta. We provide expressions for the Rayleigh number in terms of the wave vector associated with a given mode, which allow us to characterize the modes that are first to become unstable. For both the heat-flux-buoyancy-driven-instability and the magnetothermal instability, oscillatory marginal stable states are possible. © 2016 Elsevier B.V. All rights reserved. Source

Gupta A.,IIT KanpurUP | Singh D.,IIT KanpurUP | Raj P.,IIT KanpurUP | Gupta H.,Sardar Patel Post Graduate Institute of Dental and Medical science | And 2 more authors.
Journal of Bionanoscience | Year: 2015

Background: Hydroxyapatite (HAP) has been a principal mineral phase in bone cell and tooth because of several favourable properties like anti-carcinogenicity, good mechanical strength, biocompatibility etc. ZnO being an inorganic material possesses unique properties such as antisepticity, low thermal expansion coefficient, low thermal conductivity and antimicrobial properties, all of which find prominent applications in dental materials. In this regard, we have prepared a novel biomaterial blending ZnO and HAP into a nano-composite which can be incorporated directly into the restorative glass ionomer cement (GIC) to enhance its mechanical and antibacterial properties. Results: We have fabricated the ZnO-HAP nano composite using a wet chemical route through ultrasonication process. Characterization of this nano composite has been carried out with Dynamic Light Scattering (DLS), Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infra Red Spectroscopy (FTIR) and Micro-hardness testing etc. Further, the antimicrobial properties of ZnO-HAP nano composites embedded in GIC has been investigated for the E. Coli DH5α and Streptococcus mutans and we have found out the composite to significantly retard microbial activity. Copyright © 2015 American Scientific Publishers. Source

Thomas S.S.,IIT KanpurUP | Gupta S.,IIT KanpurUP | Venkatesh K.S.,IIT KanpurUP
2014 IEEE International Conference on Multimedia and Expo Workshops, ICMEW 2014 | Year: 2014

Video Summarization is a promising approach towards concatenating the moving patterns of objects into a single image. The summary attracts readers because of less browsing time, minimized spatio-temporal redundancy, and a feel of motion activity of the scene. It becomes crucial when video uncovers multiple interacting objects and the quality of the video summary in the form of resolution deteriorates in this situation. This paper attempts to address these type of concerns and presents an approach that helps the viewer to have a more automated super resolved summary of the general content of the video. We propose a method, that provides fully automated reference frame selection, frame removal, super resolution and denoising for a productive video summary involving multiple interacting objects. We have evaluated our approach on different types of videos for the purpose of their quantitative and qualitative comparison. © 2014 IEEE. Source

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