Nonlocal vibration of coupled DLGS systems embedded on Visco-Pasternak foundation

In this paper, vibration analysis of the coupled system of double-layered graphene sheets (CS-DLGSs) embedded in a Visco-Pasternak foundation is carried out using the nonlocal elasticity theory of orthotropic plate. The two DLGSs are coupled by an enclosing viscoelastic medium which is simulated as a Visco-Pasternak foundation. Considering the Von Kármán nonlinear strain-displacement-relations, the motion equations are derived using the Hamilton's principle. Differential quadrature method (DQM) is applied to obtain the frequency ratio for various boundary conditions. The detailed parametric study is conducted, focusing on the combined effects of the nonlocal parameter, aspect ratio, graphene sheet's size, boundary conditions and the elastic and viscoelastic medium coefficients on the frequency ratio of CS-DLGSs. In this coupled system, two case of DLGSs vibration are investigated and compared with each other: (1) In-phase vibration (2) Out-of-phase vibration. The results indicate that the frequency ratio of the CS-DLGSs is more than the single-layered graphene sheet (SLGS). The results are in good agreement with the previous researches.     

Nonlocal wave propagation in an embedded DWBNNT conveying fluid via strain gradient theory

Based on the strain gradient and Eringen’s piezoelasticity theories, wave propagation of an embedded double-walled boron nitride nanotube (DWBNNT) conveying fluid is investigated using Euler–Bernoulli beam model. The elastic medium is simulated by the Pasternak foundation. The van der Waals (vdW) forces between the inner and outer nanotubes are taken into account. Since, considering electro-mechanical coupling made the nonlinear motion equations, a numerical procedure is proposed to evaluate the upstream and downstream phase velocities. The results indicate that the effect of nonlinear terms in motion equations on the phase velocity cannot be neglected at lower wave numbers. Furthermore, the effect of fluid-conveying on wave propagation of the DWBNNT is significant at lower wave numbers.     

Synthesis of a carbon-14 analogue of aryl N-alkoxycarbamates and its application for synthesis of unsymmetrical N,N′-urea derivatives

Aryl N-alkoxycarbamates labeled with carbon-14 have been synthesized from aryl nitrile-[cyano-¹⁴C] as part of a 2-step sequence. The resulted carbamates were treated with amines, generating [carbonyl-¹⁴C]-Ureas in high yield and purity.     

HNN-extensions of lie algebras

We define HNN-extensions of Lie algebras and study their properties. In particular, a sufficient condition for freeness of subalgebras is obtained. We also study differential HNN-extensions of associative rings. These constructions are used to give short proofs of Malcev's and Shirshov's theorems that an associative or Lie algebra of finite or countable dimension is embeddable into a two-generator algebra.

     

Ergodic endomorphisms of compact abelian groups

We show that for a surjective endomorphism of a compact abelian group ergodicity is equivalent to a condition which impliesr-mixing for allr1, and we characterize such maps algebraically. This is then used in proving the ergodicity of an extensive class of endomorphisms of the binary sequence space. As a simple corollary it is found that one-dimensional linear cellular automata and the accumulator automata arer-mixing for allr1.This work was supported in part by grants from NSERC     

Synthesis of a <Superscript>14</Superscript>C analogue of N-(3,5-dichlorobenzyl)-4-(fluoromethoxy) benzene carboximidamide-[carboxy-<Superscript>14</Superscript>C] as NR2B-selective NMDA receptor antagonist

N-(3,5-Dichlorobenzyl)-4-(fluoromethoxy) benzenecarboximidamide labeled with carbon-14 was prepared from 4-hydroxy-benzonitrile-[cyano-¹⁴C].     

Two-Phase Inertial Flow in Homogeneous Porous Media: A Theoretical Derivation of a Macroscopic Model

The purpose of this article is to derive a macroscopic model for a certain class of inertial two-phase, incompressible, Newtonian fluid flow through homogenous porous media. Starting from the continuity and Navier–Stokes equations in each phase β and γ, the method of volume averaging is employed subjected to constraints that are explicitly provided to obtain the macroscopic mass and momentum balance equations. These constraints are on the length- and time-scales, as well as, on some quantities involving capillary, Weber and Reynolds numbers that define the class of two-phase flow under consideration. The resulting macroscopic momentum equation relates the phase-averaged pressure gradient to the filtration or Darcy velocity in a coupled nonlinear form explicitly given by

Total degradation of fenitrothion and other organophosphorus pesticides by catalytic oxidation employing Fe-TAML peroxide activators

A Fe-TAML/H2O2 catalytic oxidation process achieves facile in-solution total degradation of fenitrothion and two other organophosphorus (OP) pesticides. Degradation products have been identified and quantified providing evidence for oxidative hydrolysis, oxidative desulfuration, perhydrolysis, and deep oxidation. Degradation pathways can be selected by pH control to completely obviate all toxic residuals. Aquatic toxicity assays support the environmental compatibility of the degradation process.     

The mass-conserving solutions of Smoluchowski's coagulation equation: The general bilinear kernel

Summary It is proved that for the general bilinear kernel with arbitrary initial conditions, the solutions to the discrete coagulation equation can exhibit one of the following types of behaviour: conservation of mass for all time, conservation of mass for a finite time only, or instantaneous gelation.Research supported in part by grants from Natural Sciences and Engineering Research Council of Canada.     

Study of dynamic stability of the double-walled carbon nanotube under axial loading embedded in an elastic medium by the energy method

In this paper, the dynamic stability of single- and double-walled carbon nanotubes (SWCNT and DWCNT) under dynamic axial loading is investigated using the continuum mechanics model and the minimum total energy method. The natural frequencies of the SWCNT and the critical dynamic axial load of the SWCNT and DWCNT are obtained using the Rayleigh-Ritz method. The effects of the elastic medium and the van der Waals forces between the two layers in the DWCNT are taken into account using the Winkler model and Lennard-Jones theory, respectively. The effect of the small length scale is also considered using the Eringen Model. The critical dynamic axial load is increased by inserting an inner carbon nanotube (CNT) into an isolated CNT embedded in an elastic medium.