Study of human blood under influence of magnetic field by AC dielectric and thermally stimulated discharge current methods

Journal of Thermal Analysis and Calorimetry - The aim of the present work is to study the effect of magnetic field on thermally stimulated discharge current (TSDC) characteristics and dielectric...     

Synthesis and Mechanistic Study of Triheterocyclic 4H‐Pyrimido[2,1‐b]benzothiazole derivatives,One‐Pot Three‐component Reaction under Solvent‐Free Conditions

An efficient method has been developed for the preparation of 4H‐pyrimido[2,1‐b]benzothiazole derivatives by the condensation of aldehydes, β‐ketoester, and 2‐amino benzothiazole under solvent and solvent‐free conditions using various catalysts. The reaction uses benzothiazole as a new component, and good yield is obtained at 60–65°C under solvent‐free conditions. Atom economies, good yield, environmentally benign, and easy to work‐up are some of the important features of this protocol. The present study suggests that acetic acid and metal catalysts follow different mechanism. In acetic acid, 2‐amino benzothiazole reacts with benzaldehyde, and resultant intermediate reacts with ethyl acetoacetate to give final product, whereas in the presence of metal catalysts, 2‐amino benzothiazole first reacts with ethyl acetoacetate, and resultant intermediate reacts with benzaldehyde to give pyrimido[2,1‐b]benzothiazole.     

On stress analysis of anisotropic composites through transmission optical patterns: Isochromatics and isopachics

A real-time holographic interferometry technique is suggested for recording the isopachic patterns corresponding to transparent anisotropic composites. The isochromatic and isopachic patterns are obtained for a transparent glass-epoxy composite disk with a central hole subjected to diametral compression. A method is suggested for interpreting the optical data and to obtain the separate values of stress components. Its application is demonstrated.     

Effect of the Functionalization of the Axial Phthalocyanine Ligands on the Energy Transfer in QD-based Donor–Acceptor Pairs

This study examines the electronic coupling between quantum dots (QDs) and molecules on their surfaces as a function of the modality of their interaction. As a probe, the energy transfer (ET) between CdSe QDs and phthalocyanines (Pcs) was monitored and evaluated with regard to the functionalization of the axial phthalocyanine ligand, bulkiness of the functional group bridging the QD donor and Pc acceptor, and the number of the functionalized axial ligands. New silicon PCs and their conjugates with CdSe QDs were synthesized. The ET efficiency and kinetics were studied by steady state and femtosecond time-resolved absorption spectroscopy. We observed a decrease in ET efficiency with the increase in functional group bulkiness, which could be explained by increasing steric hindrance between the ET pair. In addition, a higher ET efficiency was observed for amino and thiol functionalized Pcs compared to Pcs without functional group on the axial alkyl chain.     

Crystalline-amorphous interaction in relation to the phase diagrams of binary polymer blends containing a crystalline constituent

The present article describes an equilibrium theory for determining binary phase diagrams of various crystalline-amorphous polymer blends by taking into account the contributions from both liquid-liquid phase separation between the constituents and solid-liquid phase transition of the crystalline component. An analytical expression for determining a crystal-amorphous interaction parameter is deduced based on the solid-liquid transition, involving the solidus and liquidus lines in conjunction with the coexistence curve of an upper critical solution temperature type. Of particular importance is that the crystalline-amorphous interaction parameter can be determined directly from the melting point depression data. The present analysis is therefore different from the conventional Flory-Huggins interaction parameter, which is associated with the liquid-liquid phase separation. The validity of the present theory is tested with the experimental phase diagrams of blends of poly(ethylene oxide)/diacrylate and poly(vinyl alcohol)/cellulose.     

Nonequilibrium molecular dynamics for bulk materials and nanostructures

We describe a method of constructing exact solutions of the equations of molecular dynamics in non-equilibrium settings. These solutions correspond to some viscometric flows, and to certain analogs of viscometric flows for fibers and membranes that have one or more dimensions of atomic scale. This work generalizes the method of objective molecular dynamics (OMD) (Dumitric? and James, 2007). It allows us to calculate viscometric properties from a molecular-level simulation in the absence of a constitutive equation, and to relate viscometric properties directly to molecular properties. The form of the solutions is partly independent of the form of the force laws between atoms, and therefore these solutions have implications for coarse-grained theories. We show that there is an exact reduction of the Boltzmann equation corresponding to one family of OMD solutions. This reduction includes most known exact solutions of the equations of the moments for special kinds of molecules and gives the form of the molecular density function corresponding to such flows. This and other consequences leads us to propose an addition to the principle of material frame indifference, a cornerstone of nonlinear continuum mechanics. The method is applied to the failure of carbon nanotubes at an imposed strain rate, using the Tersoff potential for carbon. A large set of simulations with various strain rates, initial conditions and two choices of fundamental domain (unit cell) give the following unexpected results: Stone-Wales defects play no role in the failure (though Stone-Wales partials are sometimes seen just prior to failure), a variety of failure mechanisms is observed, and most simulations give a strain at failure of 15-20%, except those done with initial temperature above about 1200 K and at the lower strain rates. The latter have a strain at failure of 1-2%.