Growth mechanism and photoluminescence property of flower-like ZnO nanostructures synthesized by starch-assisted sonochemical method

Flower-like ZnO nanostructures have been synthesized by starch-assisted sonochemical method and the effect of starch and ultrasound on the formation of ZnO nanostructure has been investigated. It is observed that starch and ultrasonic wave both plays a vital role on the growth of ZnO nanostructure. X-ray diffraction (XRD) pattern indicated that the synthesized flower-like ZnO nanostructures were hexagonal. FTIR spectrum confirms the presence of starch on the surface of flower-like ZnO nanostructure. The photoluminescence spectrum of flower-like ZnO nanostructure consists of band-edge emission at 393 nm as well as emission peaks due to defects. On the basis of structural information provided by X-ray diffraction (XRD) and morphological information by Scanning Electron Microscopy (SEM), a growth mechanism is proposed for formation of flower-like ZnO nanostructures. Differential Scanning Calorimetry (DSC) of starch in liquid medium confirms that gelatinization is a two step process involving two phases.     

Thermal behavior of carboxymethyl cellulose in the presence of polycarboxylic acid crosslinkers

Journal of Thermal Analysis and Calorimetry - In this paper, the thermodynamic (energy and exergy) analysis and water analysis of a modified solar still augmented with copper tube heat exchanger in...     

Dual functional novel catalytic Cu1−xZrxFe2O4 (x=0, 0.5, 1) nanoparticles for synthesis of polysubstituted pyridines and sunlight‐driven degradation of methylene blue

The effect of varied zirconium content on the structural, morphological, magnetic, optical, thermal and catalytic properties of nanoparticles of the ferrite Cu_1 ? xZr_xFe₂O₄ (x = 0, 0.5, 1) was investigated. The mixed ferrite was synthesized by the auto‐combustion method using nitrates of respective metals and citric acid as a chelating agent. The as‐prepared nanoparticles showed dual benefits. They were employed as a heterogeneous catalyst for one‐pot synthesis of polysubstituted pyridine derivatives as well as for catalytic degradation of industrial waste dyes such as methylene blue (MB). The highlight of the research reported is the catalytic degradation of industrial waste (MB) with high efficiency in eluent of a wide range of pH (3–13). The proposed nanoparticles arguably offer certain great advantages that include: low cost, facile nature, anti‐leaching property, magnetic recoverability and recyclability. The characterization of the as‐synthesized nanoparticles was done using various techniques. The leaching study was carried out using inductively coupled plasma optical emission spectroscopy. The formation of organic products was confirmed using Fourier transform infrared and ¹H NMR spectroscopies and examination of degradation products of MB dye was carried out using mass spectrometry and UV–visible spectroscopy.     

Atomistic damage mechanisms during hypervelocity projectile impact on AlN: A large-scale parallel molecular dynamics simulation study

Atomistic mechanisms of damage initiation during hypervelocity (15 km/s) impact on an AlN coating is investigated using parallel molecular-dynamics simulations involving 209 million atoms. On impact a strong shock wave is generated, which then splits into an elastic precursor and a structural phase transformation (SPT) waves, the latter driving a wurtzite to rocksalt structural transition. During its development, the SPT wave induces plastic processes in the intact wurtzite material, which in turn facilitate the nucleation and growth of brittle cracks. Specifically, the interface between the transformed (rocksalt) and untransformed (wurtzite) regions acts as a source of nanocavities and kink bands. They further interact with stress release waves reflected from the back surface and create cracks in mode I, from the nanocavities, and in mode II, from the kink band superdislocation boundary. Stresses are evaluated using a stoichiometric-preserving formula for virial local averages on inhomogeneous binary systems. Defects are analyzed using shortest-path ring statistics.     

Template-directed approach to solid-phase combinatorial synthesis of furan-based libraries

A novel furan based scaffold 5-hydroxymethylfurfural has been identified for the generation of combinatorial libraries using template directed approach on solid phase. This scaffold has been utilized to afford furan-based bi-heterocyclic structures with extensive chemical diversity using cycloaddition, multicomponent and cyclization reactions.     

NiO/ZnO Composite Derived Metal-Organic Framework as Advanced Electrode Materials for Zinc Hybrid Redox Flow Battery

NiO/ZnO composite derived metal-organic framework (MOF) is used as to modify carbon felt (CF) via a conventional solid-state reaction followed by ultrasonication. The prepared electrode material is used in zinc-hybrid redox flow batteries (RFBs) due to their high redox activity of Zn²⁺/Zn. The electrochemical performance of composite modified CF and pre-treated CF was studied by cyclic voltammetry (CV) in 0.5 M aqueous zinc chloride with 5 M potassium hydroxide solutions showed clear confirmation for enhanced electrocatalytic activity. The unique porous structure of NiO/ZnO-derived MOF with increased surface area improves the battery behavior significantlyThe peak current ratio for the as-prepared material is about 3 times higher than that of the pre-treated CF due to more active sites. Zinc-based RFB with modified CF electrode exhibited better electrochemical performance with voltage efficiency (VE, 88 %), which is higher than true redox flow batteries.     

The Alzheimer's beta amyloid (Abeta1-39) monomer in an implicit solvent

Results from replica-exchange and regular room temperature molecular dynamics simulations of the Alzheimer's beta amyloid (Abeta(1-39)) monomer in an implicit solvent are reported. Our data indicate that at room temperature, the monomer assumes random-coil and soluble conformations. No beta content is observed which therefore seems to be a product of oligomerization and aggregation of monomers.     

Targeting the menaquinol binding loop of mycobacterial cytochrome bd oxidase

Molecular Diversity - Mycobacteria have shown enormous resilience to survive and persist by remodeling and altering metabolic requirements. Under stringent conditions or exposure to drugs,...     

Synthesis,X-ray, 1H-NMR and DFT analysis of the phthalimide–hydrazone probes as selective anion sensor

Two simple phthalimide–hydrazone probes with nitro groups were synthesised and characterised by NMR, FT-IR, HR-MS and single crystal X-ray crystallography. The synthesised receptors were evaluated for application in anion sensing. The receptors displayed strong, sensitive and selective colouration in the presence of cyanide ions by forming a stable complex with cyanide ion. The use of variable nitro groups helped in the elucidation of the mechanism of the complex formation. The ¹H NMR spectroscopy was used to support the mechanism of the complex formation. DFT methods were used to understand the stability of the complex with respect to the reactant. The absorbance data were also compared with the TD-DFT calculated excitation parameters. The experimental results were found to correlate well with the theoretical data.