LiBH4 as solid electrolyte for Li-ion batteries with Bi2Te3 nanostructured anode

The present study highlights the first-ever application of fastest lithium (Li) ion conducting complex hydride containing cluster anions, namely lithium borohydride (LiBH₄) into an all-solid-state Li-ion battery having Bi₂Te₃ as anode material. Bi₂Te₃ nanostructures were prepared by the simple wet chemical method and characterized by their crystal structure, morphology and electronic structure using X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). SEM and TEM experiments revealed the dimensions as 20–60 nm for nanoparticles and 30–90 nm for nanosheets. The formation of Bi₂Te₃ nanostructures along with Bi₂O₃ as the residual phase is confirmed by XRD analysis. The crystallite size of nanoparticles and nanosheets are calculated as 19 nm and 39 nm respectively from XRD profile. The XPS study also confirms the formation of nanostructured Bi₂Te₃ along with Bi₂O₃. Finally, the electrochemical performance of these nanostructures is observed using the galvanostatic charge-discharge curve at 0.1C and 0.5C.     

Structural,dielectric and magnetic domains properties of Mn-doped BiFeO3 materials

The pure and Mn-doped BiFe_1−xMn_xO₃ (x = 0.00, 0.02, 0.05, 0.10) nanomaterials have been prepared by coprecipitation method. The powder X-ray diffraction pattern analysis shows a structural phase transformation from rhombohedral to orthorhombic, as Mn content in the doped BiFe_1−xMn_xO₃ increases from x = 0.00 to 0.10. The Raman spectrum analysis of BiFe_1−xMn_xO₃ also confirms structural phase transformation. The average crystallite size was calculated using the Scherrer formula and found to decrease from 100 to 60 nm. The surface structure of interconnecting cubic grain turns into spherical grains via petal-shaped grains with increasing the Mn-doping concentration. The value of dielectric constant at the frequency of 1 MHz increases rapidly from 27.2 to 76.8 whereas the tangent loss (tan δ) increases gradually from 0.26 to 0.55 as the Mn-doping concentration increases from x = 0.00 to 0.10. It reveals the enhancement of ferroelectric behavior and suppression of the leakage current density. The drastic change in the phase image contrast of magnetic force micrographs with increasing Mn-doping concentration in BiFe_1−xMn_xO₃ also indicates the improvement of the ferromagnetism.     

Hydrogen gas separation with controlled selectivity via efficient and cost effective block copolymer coated PET membranes

An efficient way is suggested to reduce the cost of block copolymer (BC) membranes while still taking advantage of their unique properties. It is demonstrated that selectivity can be kept almost the same whereas permeability is varied by using thin copolymer films on robust porous PET polymer membranes which acts as a mechanical support. So, a nanoscopic thin selective layer of the block copolymer (PS-b-P4VP) with additive is casted on the PET porous support. Selective extraction of the additive from the block copolymer thin films leads to the formation of a layer with monodispersed pores on the PET support. Measurements of the gas permeability of PET membranes of different pore size with and without block copolymer coating reveal that permeabilities of BC coated membranes decrease whereas selectivities slightly increase in comparison to the porous PET support. Coating of the membranes with BC plays a valuable role for the selectivity against gases like H₂ over CO₂. The surface morphology of the composite membranes has been determined by atomic force microscopy (AFM) showing the nanoscopic pores. Due to excellent mechanical stability and easy scale up, such membranes may be used in the gas separation technology.     

Grinding analysis of Indian coal using response surface methodology

International Journal of Coal Science & Technology - The present work discusses a systematic approach to model grinding parameters of coal in a ball mill. A three level Box–Behnken design...     

Effect of solvents and supercritical-CO2 extraction of lipids on physico-chemical,functional, pasting and rheological properties of hard,medium hard and soft wheat varieties

This study was conducted to compare the effect of lipids removal using supercrital-CO₂ extraction and organic solvents (hexane and isopropanol) from hard and soft wheat flour varieties. Flours were evaluated for physicochemical properties (protein, ash, hunter colour), sodium dodecyl sulphate-polyacrylamide gel electrophoresis, foaming properties, water and oil absorption capacity, pasting, farinographic and dynamic rheology. Protein content of flours increased after defatting and supercritical fluid extracted (SCE) wheat flours showed the highest increase. SCE flours showed higher peak viscosity than native and hexane extracted (HE) and isopropyl alcohol extracted (IPAE) flours. Functional properties improved upon defatting and the highest increase in functional properties was observed for SCE flours. Empirical and fundamental rheological measurements were affected by defatting and SCE flours showed the highest change in visco-elasticity. SC-CO2 was proved better alternative technique over conventional organic solvent methods to remove lipids from flours that brought desirable changes in some functional properties.     

Impact of Temperature on Analog/RF Performance of Dielectric Pocket Gate-all-around (DPGAA) MOSFETs

Silicon - In the present paper, the dielectric pocket (DP) technology has been employed in the Gate-All-Around (GAA) MOSFETs to improve the scalability and performance of the device. The upgraded...     

Incentive based scheme for improving data availability in vehicular ad-hoc networks

Vehicular networks are popular in recent years to provide low cost communication medium during mobility. Vehicular Delay Tolerant Networks (DTNs) are one of the major categories of emerging technology. DTNs work on carry and forward mechanism to deliver data to the destination. The network performance gets severely affected due to reluctance shown by selfish nodes where few nodes show no interest in forwarding others data due to lack of any personal profit. The proposed mechanism is based on coalition game theory and discusses about incentive based mechanism which provides incentive to nodes which are forwarding data to forward to destination and motivates other vehicles in the network to participate in coalition to forward data. This scheme not only encourages other selfish nodes to forward their private data and other nodes’ public data as early as possible to destination but also increases reliability in the network as more nodes show their interest in selected routing protocol. The proposed scheme outperforms in overall benefit earned by individual node and whole coalition, and increases mutual cooperation which improves availability of data in the network.     

Optimization of the Pd–Sn–GNS nanocomposite for enhanced electrooxidation of methanol

Highly dispersed Pd nanoparticles with varying loadings (15–40 wt%) and (20 − x)%Pd–x%Sn (where x = 1, 2, 3 and 5) nanocomposites are obtained on graphene nanosheets (GNS) by a microwave-assisted ethylene glycol (EG) reduction method for methanol electrooxidation in alkaline solution. The electrocatalysts were characterized by XRD, SEM, TEM, cyclic voltammetry, and chronoamperometry. The study shows that the Pd nanoparticles on GNS are crystalline and follow the face centered cubic structure. Introduction of a small amount of Sn (1–5 wt%) shifts the characteristic diffraction peaks for Pd slightly to a lower angle. The electrocatalytic performance of the Pd/GNS electrodes has been observed to be the best with 20 wt% Pd loading; a higher or lower loading than 20 wt% Pd produces an electrode with relatively low catalytic activity. The apparent catalytic activity of this active electrode at E = −0.10 V is found to improve further by 79% and CO poisoning tolerance by 40% with introduction of 2 wt% Sn. Among the electrodes investigated, the 18%Pd–2%Sn/GNS exhibited the greatest electrocatalytic activity toward methanol electrooxidation.     

Effect of Specific Energy Input on Microstructure and Mechanical Properties of Nickel-Base Intermetallic Alloy Deposited by Laser Cladding

This article describes the microstructural features and mechanical properties of nickel-base intermetallic alloy laser-clad layers on stainless steel-316?L substrate, with specific attention on the effect of laser-specific energy input (defined as the energy required per unit of the clad mass, kJ/g) on the microstructure and properties of the clad layer, keeping the other laser-cladding parameters same. Defect-free clad layers were observed, in which various solidified zones could be distinguished: planar crystallization near the substrate/clad interface, followed by cellular and dendritic morphology towards the surface of the clad layer. The clad layers were characterized by the presence of a hard molybdenum-rich hexagonal close-packed (hcp) intermetallic Laves phase dispersed in a relatively softer face-centered cubic (fcc) gamma solid solution or a fine lamellar eutectic phase mixture of an intermetallic Laves phase and gamma solid solution. The microstructure and properties of the clad layers showed a strong correlation with the laser-specific energy input. As the specific energy input increased, the dilution of the clad layer increased and the microstructure changed from a hypereutectic structure (with a compact dispersion of characteristic primary hard intermetallic Laves phase in eutectic phase mixture) to near eutectic or hypoeutectic structure (with reduced fraction of primary hard intermetallic Laves phase) with a corresponding decrease in the clad layer hardness.     

Mössbauer studies of iron doped poly(methyl methacrylate) before and after ion beam modification

High-energy MeV ions from accelerators are known to produce drastic modifications in polymers. The typical effects include chain scissions, crosslinks, molecular emission and double bond formation. Poly(methyl methacrylate) was doped with Fe(III) and irradiated with 95 MeV O⁷⁺ ions.⁵⁷Fe-Mössbauer studies were done on the doped samples before and after irradiation. Before irradiation, no Mössbauer absorption was observed. The irradiated samples showed a good Mössbauer absorption, which seems to indicate that there is a significant interaction between the metal ion and the polymer matrix. Two possibilities exist at these doses (～ 22 × 10¹² ions/cm): Fe(III) ions may be bridging the various polymer segments through crosslinking or amorphization of the sample leading to Fe-C bonding. Studies of FTIR, conductivity and glass transition temperatures on these samples support these observations.