On-demand fuzzy clustering and ant-colony optimisation based mobile data collection in wireless sensor network

Wireless Networks - In a wireless sensor network (WSN), sensor nodes collect data from the environment and transfer this data to an end user through multi-hop communication. This results in high...     

Effects of Defects on Charge Transport in Armchair Nanoribbon WS2 Field Effect Transistors

We have studied the WS₂ armchair nanoribbon with various defects like vacancy, edge roughness, twist, turn and ripple and compared how the bandgap changes due to such defects with the bandgap of a nanoribbon with no defects. Materials like WS₂ and other transition metal dichalcogenides (MX₂) have a graphene like layered structure with hexagonal rings and have properties that have attracted a lot of interest. Hence it is essential to study the changes in the band structure of the nanoribbon of WS₂ due to the inclusion of defects like vacancy, rough edge, wrap, ripple and twist for making any device based on WS₂.     

Study of photovoltaic performance of host‐guest system comprising photoluminescent polyurethane and rhodamine B dye

The photovoltaic property of Rhodamine B dye embedded into Poly(tolyl‐1,1′‐binaphthyl carbamate) (PU₁) and poly(hexamethylene‐1,1′‐binaphthyl carbamate) (PU₂) matrices have been evaluated using host‐guest approach. The photoactive layer comprising photoluminescent polymer matrix (PU₁ or PU₂), Rhodamine B and TiO₂ nanoparticles were prepared by spin casting method. The power conversion efficiency (PCE) the photovoltaic devices based on PU₁ and PU₂ matrices were found to be 0.043% and 0.029%, respectively. PCE of the photovoltaic devices were limited due to low lying highest occupied molecular orbital of PU₁ and PU₂ polymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Deep neural networks for automatic grain-matrix segmentation in plane and cross-polarized sandstone photomicrographs

Applied Intelligence - Grain segmentation of sandstone that is partitioning the grain from its surrounding matrix/cement in the thin section is the primary step for computer-aided mineral...     

Modeling blast furnace productivity using support vector machines

Productivity of a modern generation blast furnace was modeled with the help of a leading supervised learning tool viz. Support Vector Machines in the form of (1) minimum error, maximum margin classification function in binary setting of productivity classes (low/high) and (2) the class-specific regression functions for real values of productivity based on epsilon sensitive loss function and minimum regulated risk. The SVMs were trained with large number data-points each of which consisted of a setting of 21 critical input parameters of blast furnace, corresponding productivity value observed, and the productivity class (low/high) attributed. During the training session of the SVMs, the vectors of critical input parameters were required to be mapped into high-dimensional feature space via Radial basis kernel as function and the optimum SVM-RBF classifying function with chosen setting of its hyperparameters that had good generalization property was found using quadratic optimization. The SVM-RBF classifying function could be used to predict the class of productivity (low/high) for any given setting of the critical input parameters. Class-specific SVM-RBF regression models were also developed for both low as well as high-productivity classes and these models could be used to predict real value of productivity for any given setting of the critical input parameters. The SVM-RBF regression model fitted to the high-productivity class was subjected to constrained nonlinear optimization treatment to find the optimum setting of the critical input parameters that gave maximum productivity. The optimum setting of the critical parameters could be used as the target setting obtaining high productivity in the blast furnace.     

Hydrogen storage capacity of bundles of single‐walled carbon nanotubes with defects

We study the hydrogen storage capacity of bundles of single‐walled carbon nanotubes (SWCNT) at 80 and 298 K using molecular dynamics simulations. The effect of packing on the storage capacity of the bundles is studied using triangular and square arrays of nanotubes with various separation distance between adjacent nanotubes. The gravimetric storage capacity of the bundles increases with the separation distance between individual nanotubes. At low temperature, the storage capacity of bundles is significantly lower than for isolated SWCNT as the intertube distance is smaller than the adsorbed layer thickness of hydrogen. At high temperature, the adsorbed layer thickness corresponds to only a monolayer of hydrogen around SWCNTs, and hence, hydrogen is captured in the interstitial spaces within the bundle. As the groove volume in the square array is higher than that in the triangular array, the storage capacity of the bundle with square array is higher. An introduction of the Stone–Wales defects on the surface of nanotubes further increases the storage capacity of the bundle due to the higher binding energy of the 8‐member rings of the defective SWCNTs. We also observe that more hydrogen molecules are packed in the interstitial spaces due to the deformation of the nanotubes caused by the presence of defective sites. Copyright © 2016 John Wiley & Sons, Ltd.     

Effectivity of copper and cadmium sulphide nanoparticles in mitotic and meiotic cells of Nigella sativa L. (black cumin) – can nanoparticles act as mutagenic agents?

The present investigation deals with wet chemical preparation and characterisation of copper (Cu) and cadmium sulphide (CdS) nanoparticles (NPs) (using UV–visible spectra, Fourier transform infra-red scattering, X-ray diffraction, dynamic light scattering, field emission scanning electron microscopy and transmission electron microscopy) and their effectivity on mitotic and meiotic cells of Nigella sativa L. (Ranunculaceae) in comparison to ethyl methanesulphonate (EMS) and gamma irradiations. The objective of the study is to foresee whether Cu- and CdS-NPs can induce similar type of chromosomal aberrations as that of EMS and gamma irradiations, or not. Dry seeds of N. sativa (2n = 12) are exposed to Cu- and CdS-NPs (0.25, 0.50 and 1.0 µg/ml; 3 and 6 h), EMS (0.25, 0.50 and 1.0%; 3 and 6 h) and doses of gamma irradiations (25, 50, 100, 200 and 300 Gy). Cu-NPs (range: 25.7 to 120.4 nm; 33.2 nm ± 9.6) and CdS-NPs (range: 29.4 to 115.7 nm; 37.8 nm ± 10.7) are both cubical to spherical in shape. NPs are found to induce similar responses as that of the studied conventional mutagens, in relation to physiological and chromosomal (mitotic and meiotic) attributes. Uptake of Cu- and CdS-NPs in seedlings is also studied using atomic absorption spectroscopy. Results suggest that Cu- and CdS-NPs can act as mutagenic agent, a pioneer report of its kind.     

Nanostructured MoSx-based thin films obtained by electrochemical reduction

The in situ electrochemical deposition of nanostructured MoS_x (x = 1.5–1.7) based thin films on various substrates from aqueous solutions is reported. The as-deposited amorphous films transform on annealing into crystalline ones as revealed by a stepwise high temperature X-ray diffraction (XRD). Both Raman spectroscopy and XRD crystal structure analyses confirmed the formation of inorganic fullerene-MoS_x nanoparticles (IF-MoS_x). The as-deposited thin films have a featureless surface morphology, but after annealing either a nanotube or a nanorod structure along with numerous smaller nanoballs appear at the surface. An investigation by transmission electron microscopy unearths the presence of nanoballs, nanoribbons, and nanotubes throughout the annealed MoS_x thin films. The size of the nanoballs is in the range of 5–10 nm. The nanotubes have a diameter of 10–400 nm, and a length of up to several micrometers as evidenced by SEM. The catalytic effect of transition metals on the growth of nanotubes is noticed. The temperature-induced transformation from amorphous to crystalline structured MoS_x films results in a large lowering of the coefficient of friction under sliding against corundum in ambient air of 50% relative humidity.