Paradoxes in electrochemistry and their resolution

It was demonstrated that many puzzling issues encountered in interpreting results of electrochemical experiments can be resolved based on the general principles of thermodynamics and electrostatics.     

An improved variational iteration method for solving coupled KdV and Boussinesq-like B(m, n) equations

In this article, we implement a new analytical technique; He’s variational iteration method for solving the coupled KdV and Boussinesq-like equations. In this method, first general Lagrange multipliers are introduced to construct correction functional for the problems. The multipliers in the functional can be identified optimally via the variational theory. Next the components of obtained iteration formulae defined by partial sum of other sequence, specially constructed according to Adomian’s decomposition method (ADM). Also according to ADM we used a partial sum of Adomian polynomials instead of nonlinear terms in iteration formulae. The initial approximations can be freely chosen with possible unknown constants, which can be determined by imposing the initial conditions. The results reveal that the proposed method is very effective and can be applied for other nonlinear problems.     

Rational design of biocompatible IPNs hydrogels containing carboxymethyl starch and trimethyl chitosan chloride with high antibacterial activity

Cellulose - Antimicrobial hydrogels have enticed a major concern for repairing soft tissues, particularly prohibiting bacterial infections that are frequently accompanied by impaired wound healing....     

Survival time of a heterogeneous random walk in a quadrant

We obtain upper Gaussian estimates of transition probabilities of inhomogeneous random walks on the positive quadrant. Among the most important steps in our proof are comparison arguments based on discrete variants of the Harnack principle and large deviations estimates.     

Experimental Investigation of Heat Transfer for a Jet Impinging Obliquely on a Flat Surface

An experimental study investigated the effects of the inclination of an impinging circular jet on heat transfer from a horizontal flat plate. Local Nusselt number distribution was determine depending on inclination angle, jet-to-plate distance, and Reynolds number. The results show that the maximum heat transfer point moves toward the uphill side of the plate and that the maximum heat transfer decreases as the inclination angle decreases. The correlations were conducted to predict maximum and local Nusselt number as a function of Re, θ, L/D, and x/D for three specific regions.     

A numerical study of the null boundary controllability of a convection diffusion equation

In this paper we study numerically the cost of the null controllability of a linear control parabolic 1-D equation as the diffusion coefficient tends to 0. For this linear control parabolic 1-D equation, we know from a prior work by J.-M. Coron and S. Guerrero (2005), that, when the diffusion coefficient tends to 0, for a small controllability time, the norm of the optimal control tends to infinity and that, if the controllability time is large enough, this norm tends to 0. For controllability times which are not covered by this work, we estimate numerically the norm of the optimal control as the diffusion coefficient tends to 0. To cite this article: A. Salem, C. R. Acad. Sci. Paris, Ser. I 347 (2009).     

Novel synthesis, reactivity, and stereochemistry of substituted 3-trifluoromethyl- and 3-perfluoroalkyl-3-phenoxyprop-2-enal

Substituted 3-phenoxy-3-perfluoroalkylprop-2-enals 3a-s are synthesized in high yields starting from a gem-iodoacetoxy derivative 1 and phenoxides 2. Then efficient syntheses of push-pull derivatives 4, 5,8a,b, and nonconjugated analogues 6 and 7 illustrate the synthetic potentialities of 3. Stereochemical studies of these perfluoroalkyl-containing trisubstituted olefinic derivatives 3-8b revealed that the (4)J(CF) coupling constant observed in the (13)C NMR spectra was crucial in the determination of their configurations and conformations in solution. The solvent polarity effect on the stereochemistry of push-pull compounds 3-5 and 8a,b was studied. Unusual significant medium polarity effect on the stereochemistry of imino enol ether derivative 4 was observed.     

Existence results of solutions for anti-periodic fractional Langevin equation

Recently, Khalili and Yadollahzadeh [ Y. Khalili and M. Yadollahzadeh, Existence results for a new class of nonlinear Langevin equations of fractional orders, Iranian J. Sci. Tech., Trans. A: Sci., 2019, 43(5), 2335–2342] have investigated the uniqueness and existence of solution $u(t),~t\in[0,1]$ for a class of nonlocal boundary conditions to fractional Langevin equation. The authors used the boundary condition $u"(0)=0$ by incorrect method. In the current contribution, we show the correct method for using this condition and study the existence and uniqueness of solution for the same class of equation in slightly different form with anti-periodic and nonlocal integral boundary conditions as well as the boundary condition $u"(0)=0$. An exemplar is provided to illustrate our results.     

Synthesis of thiopyrano[4″,3″:4′,5′]pyrido[3′,2′:4,5]furo[3,2-d]pyrimidines

<正>Reactions of the 6-hydroxy-thiopyrano[3,4-c]pyridine-5-carbonitrile derivative 1 withα-halo-carbonyl compounds gave the ortho-substituted intermediates 2a-c which were converted into furo[2,3-b]thiopyrano[4,3-d]pyridines 3a-c by fusion of a furan moiety under basic conditions.Further cyclization of 3a-c led to a fusion of a pyrimidine ring,yielding the tetracyclic products 6,7 and 8.In addition,condensation of 6 with various aromatic aldehydes afforded the corresponding imines 9a,b.Mannich reaction of 7 gave products 10a,b.