Polymer nanocomposites containing β-Bi2O3 and silica nanoparticles: Thermal stability,surface topography and X-ray attenuation properties

Silicone polymer-based nanocomposites containing β-Bi₂O₃ nanoparticles with varying concentrations of silica nanoparticles are successfully prepared and characterized for thermal stability, surface topography, and X-ray attenuation property. Of all the samples studied here, silicone polymer of higher density (S1) containing β-Bi₂O₃ (50 wt%) and silica (0.025 wt%) nanoparticles is found to be thermally stable upto 424 and 375°C in argon and oxygen atmosphere, respectively. The atomic force microscopy image of top and cleaved surface of this nanocomposite exhibits an average roughness of 12 and 506 nm, respectively. It also exhibits the highest X-ray attenuation property, among the samples analyzed here, against X-rays of energies in the range of 30–66 keV. Therefore, S1 silicone polymer containing β-Bi₂O₃ and silica (0.025 wt%) nanoparticles is a potential material for the development of lead-free and X-ray opaque aprons, gloves, thyroid collar, gonad shield, and so on.     

A Study on Various Attacks and Detection Methodologies in Software Defined Networks

Wireless Personal Communications - The Software Defined Networks (SDN) is widely used in many industrial and enterprise networking applications due to its flexibility and gaining popularity. It...     

Shared control architectures for vehicle steering

Cognition, Technology & Work - Various schemes for sharing control between a human driver and automation system have been proposed, each with the aim of freeing attention while supporting...     

Synthesis and on-line ultrasonic characterisation of bulk and nanocrystalline La0.68Sr0.32MnO3 perovskite manganite

La_0.68Sr_0.32MnO₃ perovskite manganite samples were prepared using sonochemical reactor and solid state reaction technique. The ultrasonic velocity, attenuation and elastic moduli of samples were measured using ultrasonic through transmission method, at a fundamental frequency of 5 MHz over a wide range of temperatures. The temperature dependence of the ultrasonic parameters shows an interesting anomaly in all the compositions. The observed dramatic softening and hardening in sound velocities or attenuation is related to phase transitions. The linear magnetostriction effect is more dominant in the perovskite than volume magnetostriction effect which is evident from the observed anomalous in both longitudinal and shear velocities and attenuation. Further, a decrease in grain size in the sintered sample leads to a shift in the ferromagnetic transition temperature (T_C) from 375 to 370 K.     

Dietary spices protect against hydrogen peroxide-induced DNA damage and inhibit nicotine-induced cancer cell migration

Spices are rich sources of antioxidants due to the presence of phenols and flavonoids. In this study, the DNA protecting activity and inhibition of nicotine-induced cancer cell migration of 9 spices were analysed. Murine fibroblasts (3T3-L1) and human breast cancer (MCF-7) cells were pre-treated with spice extracts and then exposed to H₂O₂ and nicotine. The comet assay was used to analyse the DNA damage. Among the 9 spices, ginger, at 50 μg/ml protected against 68% of DNA damage in 3T3-L1 cells. Caraway, cumin and fennel showed statistically significant (p < 0.05) DNA protecting activity. Treatment of MCF-7 cells with nicotine induced cell migration, whereas pre-treatment with spices reduced this migration. Pepper, long pepper and ginger exhibited a high rate of inhibition of cell migration. The results of this study prove that spices protect DNA and inhibit cancer cell migration.     

Generation of Monodisperse Inorganic–Organic Janus Microspheres in a Microfluidic Device

This study presents a simple synthetic approach for the in situ preparation of monodisperse hybrid Janus microspheres (HJM) having organic and inorganic parts in a PDMS‐based microfluidic device. Based on the mechanism of shear‐force‐driven break‐off, merged droplets of two photocurable oligomer solutions having distinctive properties are generated into an immiscible continuous phase. Functionalized perfluoropolyether (PFPE) as the organic phase and hydrolytic allylhydridopolycarbosilane (AHPCS) as the inorganic phase are used for the generation in aqueous medium of HJM with well‐defined morphology and high monodispersity (average diameter of 162 µm and a 3.5% coefficient of variation). The size and shape of the HJM is controlled by varying the flow rate of the disperse and continuous phases. The HJM have two distinctive regions: a hydrophobic hemisphere (PFPE) having a smooth surface and a relatively hydrophilic region (AHPCS) with a rough, porous surface. In addition, pyrolysis and subsequent oxidation of these HJM convert them into SiC‐based ceramic hemispheres through the removal of the organic portion and etching off the silica shell. The selective incorporation of magnetic nanoparticles into the inorganic part shows the feasibility of the forced assembly of HJM in an applied magnetic field.     

Modeling the Axial Mechanical Response of Amorphous Fe45Ni45Mo7B3 Honeycombs

The high yield strength and elastic modulus of metallic glasses suggests they could perform an important role in structural applications. To produce materials with a high strength-to-weight ratio and excellent mechanical energy absorption, it is advantageous to form amorphous alloys as cellular solids. Using the elastic properties of slip cast amorphous Fe₄₅Ni₄₅Mo₇B₃ ribbons, a metallic glass honeycomb was manufactured with a unique manufacturing approach. First, prototypes were manufactured with a porosity of 97?pct, a cell wall thickness of 0.03?mm, and a cell size of 3?mm. Experimentally measured mechanical properties were reasonably similar to analytical models. This suggests that a three-times improvement in the yield strength along the out-of-plane direction is achievable when compared with crystalline aluminum honeycombs. An analytical model was developed to predict the relative density and the compressive stress (?? ₃ ^* ) in the out-of-plane (X ₃) direction of the ??teardrop?? cellular structure. The predictions are validated by initial experimental results and compare well with existing analytical models for hexagonal cellular materials.