Magnetic proximity effect as a pathway to spintronic applications of topological insulators

Spin-based electronics in topological insulators (TIs) is favored by the long spin coherence(1,2) and consequently fault-tolerant information storage. Magnetically doped TIs are ferromagnetic up to 13 K,(3) well below any practical operating condition. Here we demonstrate that the long-range ferromagnetism at ambient temperature can be induced in Bi(2-x)Mn(x)Te(3) by the magnetic proximity effect through deposited Fe overlayer. This result opens a new path to interface-controlled ferromagnetism in TI-based spintronic devices.     

Deep learning architectures for land cover classification using red and near-infrared satellite images

Multimedia Tools and Applications - Classification of remotely sensed data requires the modelling of suitable image processing algorithms. The rise of machine learning systems upgraded the...     

Biomechanics of breast tumor: effect of collagen and tissue density

Various clinical studies have established the influence of breast tissue density on the onset and formation of breast tumor. In this paper we develop a mathematical correlation of the change in density with the change in collagen content and the corresponding change in the bio-mechanical characteristics of the breast tissue. The developed computational model is used in understanding the mechanical response of the breast tissue using multiscale mathematical homogenization techniques. The mathematical modeling is carried out using hyperelastic material formulations for the macro-scale finite element simulations and small strain material models for the lower order homogenization.     

Dynamic mechanical analysis of ethylene–propylene–diene monomer rubber and styrene–butadiene rubber blends

The effects of blend ratio, crosslinking systems, and fillers on the viscoelastic response of ethylene–propylene–diene monomer (EPDM)/styrene–butadiene rubber (SBR) blends were studied as functions of frequency, temperature, and cure systems. The storage modulus decreased with increasing SBR content. The loss modulus and loss tangent results showed that the EPDM/SBR blend vulcanizate containing 80 wt % EPDM had the highest compatibility. Among the different cure systems studied, the dicumyl peroxide cured blends exhibited the highest storage modulus. The reinforcing fillers were found to reduce the loss tangent peak height. The blend containing 40 wt % EPDM showed partial miscibility. The dispersed EPDM phase suppressed the glass‐transition temperature of the matrix phase. The dynamic mechanical response of rubbery region was dominated by SBR in the EPDM–SBR blend. The morphology of the blend was studied by means of scanning electron microscopy. The blend containing 80 wt % EPDM had small domains of SBR particles dispersed uniformly throughout the EPDM matrix, which helped to toughen the matrix and prevent crack propagation; this led to enhanced blend compatibility. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The effect of electrode films on the electrical resistance of thin tin films

The variation in resistance of thin films of tin deposited onto glass substrates was studied using pre-deposited gold, silver, aluminum and tin electrodes. The percentage variation in resistance of the tin films was found to be different for the different electrode materials. The structural features of the tin-electrode film junctions were investigated using optical and scanning electron microscopes. The difference between the variations in resistance with time for different electrode films is explained on the basis of interdiffusion, alloy formation and oxidation at the electrode film junctions.     

Optimal load frequency control through combined state and control gain estimation for noisy measurements

Combined estimation of state and feed-back gain for optimal load frequency control is proposed. Load frequency control (LFC) addresses the problem of controlling system frequency in response to disturbance, and is one of main research areas in power system operation. A well acknowledged solution to this problem is feedback stabilization, where the Linear Quadratic Regulator (LQR) based controller computes the feedback gain K from the known system parameters and implements the control, assuming the availability of all the state variables. However, this approach restricts control to cases where the state variables are readily available and the system parameters are steady. Alternatively, by estimating the states continuously from available measurements of some of the states, it can accommodate dynamic changes in the system parameters. The paper proposes the technique of augmenting the state variables with controller gains. This introduces a non-linearity to the augmented system and thereby the estimation is performed using an Extended Kalman Filter. This results in producing controller gains that are capable of controlling the system in response to changes in load demand, system parameter variation and measurement noise.     

Molecular transport of benzene and methyl-substituted benzenes into filled natural rubber sheets

Sorption and diffusion of benzene and methyl-substituted benzenes were investigated through natural rubber reinforced with four types of carbon black: superbrasion furnace, intermediate superabrasion furnace, high-abrasion furnace, and semireinforcing furnace. The rubber loaded with superabrasion furnace took the lowest amount of solvents among all the samples. It was observed that the mechanism of transport deviates from the normal Fickian trend with a decrease in particle size of the fillers. The diffusion coefficients were determined considering the changes in thickness as well as the diameter of the natural rubber samples. From the temperature dependence of diffusivity, the activation energy for the diffusion process was computed. The sorption data were used to estimate the rubber-solvent interaction parameter, enthalpy, and entropy of the sorption process. © 1996 John Wiley & Sons, Inc.     

Interaction of silica and carbon black fillers with natural rubber/poly(ethylene‐co‐vinyl acetate) matrix by swelling studies

The interaction of a black filler and a white filler, which are extensively used in the rubber industry, with natural rubber/poly (ethylene‐co‐vinyl acetate) (NR/EVA) blends vulcanized by DCP has been examined by equilibrium swelling technique. Blends loaded with intermediate super abrasion furnace black (ISAF) and those with silica (SiO₂), of same loading, have been used. The silica incorporated blends sorbed a higher amount of aromatic solvents, compared with the ISAF filled blends, when NR was the continuous phase. However, the silica filled systems showed lower sorption characteristics when EVA became the continuous phase. This has been explained in terms of the differences in the interaction between the filler particles and the blend components. The swelling coefficient, diffusion coefficient, and molar mass between crosslinks have been computed to complement the experimental observations. POLYM. COMPOS., 28:705–712, 2007. © 2007 Society of Plastics Engineers