CuI@Al2O3 catalyzed synthesis of 2-aminonicotinonitrile derivatives under solvent free condition

A Green approach for the synthesis of 2-aminonicotinonitriles from oxime acetate as enamine precursor, aldehyde and malononitrile under neat condition without the use of additive in presence of CuI@Al₂O₃ nanocatalyst is reported. Wide substrate scope, high yield in shorter reaction time, avoid the usage of bases/additives with better green chemistry matrices like low E factor and PMI, high values of atom economy, carbon efficiency and reaction mass efficiency as compared with literature methods. CuI@Al₂O₃ nanocatalyst was recovered and recycled five times without significant decrease in its catalytical activity.     

A novel bacteriohopanoid from Celtis australis L.bark

A novel bacteriohopanoid elucidated as 3β-hydroxy-35-(cyclohexyl-5’-propan-7’-one)-33-ethyl-34-methyl-bactereohopane(1) has been isolated from the bark of Celtis australis(Ulmaceae) together with three known compounds apigenin,quercetin and its glucoside.The structure of 1 was characterized by means of chemical and spectral methods including advanced 2D NMR studies.     

Bio-Assisted Preparation of Nano Zinc Oxide and Its Behavior Towards Textile Azo Pollutants

High Energy Chemistry - Recent reports on nanoparticles rise significantly as they possess numerous applications in medical, material science, optics, and bioscience etc. Nanoparticles show unique...     

On high-order shock-fitting and front-tracking schemes for numerical simulation of shock–disturbance interactions

High-order methods that can resolve interactions of flow-disturbances with shock waves are critical for reliable numerical simulation of shock wave and turbulence interaction. Such problems are not well understood due to the limitations of numerical methods. Most of the popular shock-capturing methods are only first-order accurate at the shock and may incur spurious numerical oscillations near the shock. Shock-fitting algorithms have been proposed as an alternative which can achieve uniform high-order accuracy and can avoid possible spurious oscillations incurred in shock-capturing methods by treating shocks as sharp interfaces. We explore two ways for shock-fitting: conventional moving grid set-up and a new fixed grid set-up with front tracking. In the conventional shock-fitting method, a moving grid is fitted to the shock whereas in the newly developed fixed grid set-up the shock front is tracked using Lagrangian points and is free to move across the underlying fixed grid. Different implementations of shock-fitting methods have been published in the literature. However, uniform high-order accuracy of various shock-fitting methods has not been systematically established. In this paper, we carry out a rigorous grid-convergence analysis on different variations of shock-fitting methods with both moving and fixed grids. These shock-fitting methods consist of different combinations of numerical methods for computing flow away from the shock and those for computing the shock movement. Specifically, we consider fifth-order upwind finite-difference scheme and shock-capturing WENO schemes with conventional shock-fitting and show that a fifth-order convergence is indeed achieved for a canonical one-dimensional shock-entropy wave interaction problem. We also show that the method of finding shock velocity from one characteristic relation and Rankine–Hugoniot jump condition performs better than the other methods of computing shock velocities. A high-order front-tracking implementation of shock-fitting is also presented in this paper and nominal rate of convergence is shown. The front-tracking results are validated by comparing to results from the conventional shock-fitting method and a linear-interaction analysis for a two-dimensional shock disturbance interaction problem.     

Biosynthesized Zinc Oxide Nanoparticles as Efficient Photocatalytic and Antimicrobial Agent

This work reports an innovative, effortless and inexpensive method for the preparation of ZnO nanoparticles by green approach using leaf extract of Piper betleas a reducing-stabilizing negotiator. The prepared ZnO NPs were characterized through XRD, FTIR, UV–Visible spectroscopy, and EDX etc. The band gap energy of the sample was estimated as 3.41 eV which is larger than the bulk ZnO (E_g?=?3.37 eV). The observed blue shift is attributed to the quantum confinement of excitons. FTIR analysis showed the presence of alkaloids, flavonoids, polyphenols, and terpenoid. TEM analysis showed that each nanoparticle comprised of 1 to 2 nano-crystallites. Photocatalytic activity results revealed that ZnO-NPs prepared through green synthesis route were found to be efficient in the degradation of toxic reactive red dye with degradation efficiency of 96.4% having high photodegradation rate-constant of 1.6?×?10^–2 min^?1. As an antimicrobial agent, the ZnO NPs are effective against both gram-positive (Bacillus subtilis) and negative bacteria (Escherichia coli), with the zones of clearance as 16.4 and 14.3 mm, respectively. Therefore, present research signifies an effective approach to utilize as-prepared ZnO NPs as efficient photocatalysts as well as antimicrobial agent.

     

Quaternionic Formulation of Supersymmetric Quantum Mechanics

Quaternionic formulation of supersymmetric quantum mechanics has been developed consistently in terms of Hamiltonians, super partner Hamiltonians, and supercharges for free particle and interacting field in one and three dimensions. Supercharges, super partner Hamiltonians and energy eigenvalues are discussed and it has been shown that the results are consistent with the results of quantum mechanics.     

A hybrid finite/boundary element method for periodic structures on non-periodic meshes using an interior penalty formulation for Maxwell’s equations

This paper presents a hybrid finite element/boundary element (FEBE) method for periodic structures. Periodic structures have been efficiently analyzed by solving for a single unit cell utilizing Floquet’s theorem. However, most of the previous works require periodic meshes to properly impose the boundary conditions on the outer surfaces of the unit cell. To alleviate this restriction, the interior penalty method is adopted and implemented in this work. Also, the proper treatment of the boundary element part is addressed to account for the non-conformity of the boundary element mesh. Another ingredient of this work is the use of the efficient boundary element computation, accelerated by the Ewald transformation for the calculation of the periodic Green’s function. Finally, the method is validated through examples which are discretized without the constraint of a periodic mesh.     

Grafting onto wool. XXV. Effect of acids on γ-radiation-induced graft copolymerization of methyl methacrylate onto wool fiber

Graft copolymerization of methyl methacrylate (MMA) onto Himachali wool fiber has been investigated in aqueous medium by using γ irradiation from a 2100 Ci⁶⁰CO source as means of initiation. Graft copolymerization was carried out by the mutual method in nitrogen atmosphere as well as in air. Effect of mineral acids and acetic acid on percentage of grafting was studied. Percentage of grafting was determined as functions of total dose, concentration of monomer, and concentration of acids. Maximum percentage of grafting in the presence of acids occurred in nitrogen atmosphere at a total dose of 1.05 MR. All the acids were found to influence grafting and the reactivity of different acids towards graft copolymerization was found to follow the order: H₂SO₄ > HCl > HNO₃ > HC1O₄ > HOAc. An attempt has been made to explain the reactivity order of different acids in the light of the mechanism proposed for γ-irradiation-induced graft copolymerization of vinyl monomer onto wool fiber.