Matrimid–polyaniline/clay mixed‐matrix membranes with plasticization resistance for separation of CO2 from natural gas

Mixed‐matrix membranes (MMMs) of Matrimid® and polyaniline/clay (PC) are investigated for CO₂/CH₄ separation and CO₂‐induced plasticization. PC particles are synthesized through in‐situ polymerization of aniline in the presence of organophilic clay and then incorporated into Matrimid by solution casting method. Chemical structure and morphology of PC powder and fabricated membranes are analyzed by Fourier transform infrared (FTIR), X‐ray diffraction (XRD), differential scanning calorimetry/thermogravimetric analysis (DSC/TGA) and scanning electron microscopy (SEM). The XRD spectra of PC particles show the exfoliation of silicate layers throughout the polyaniline (PAni) matrix, and SEM images indicate flower‐petal morphology for PC particles. The permeability values of CO₂ and CH₄ increase 30–35% by incorporation of 10 wt% PC without any significant drop in selectivity. PC particles with flower‐petal morphology plays an important role in increasing the gas permeability values of both gases while Matrimid is the only phase that controls CO₂/CH₄ selectivity. The plasticization pressure was increased to 30 bar by incorporation of 10 wt% PC in the Matrimid matrix. CO₂ permeability and p_plast improved 35% and 200%, respectively, resulting in 300% enhancement in the capacity of MMM in the purification of natural gas with a selectivity of about 40. Copyright © 2016 John Wiley & Sons, Ltd.     

Analytic solution for heat transfer of a third grade viscoelastic fluid in non-Darcy porous media with thermophysical effects

An analytic approximate solution is presented for the natural convective dissipative heat transfer of an incompressible, third grade, non-Newtonian fluid flowing past an infinite porous plate embedded in a Darcy–Forchheimer porous medium. The mathematical model is developed in an $(x\text{,}y)$ coordinate system. Using a set of transformations, the momentum equation is rendered one-dimensional and a partly linearized heat conservation equation is derived. The viscoelastic formulation presented by Akyildiz [Akyildiz FT. A note on the flow of a third grade between heated parallel plates. Int J Non-Linear Mech 2001;36:349–52] is adopted, which generates lateral mass and viscoelastic terms in the heat conservation equation, as well as in the momentum equation. A number of special cases of the general transformed model are discussed. A homotopy analysis method (HAM) is implemented to solve, with appropriate boundary conditions, the coupled third-order, second degree ordinary differential equation for momentum and the second-order, fourth degree heat conservation equation.     

Phosphoramides: Synthesis,Spectroscopy, and X‐ray Crystallography

A series of new phosphoramides with general formula RP(O)X₂, where R = amino/p‐methylphenoxy and X = amine, were synthesized and characterized by ¹H, ¹³C, ³¹P nuclear magnetic resonance (NMR), and infrared (IR) spectroscopy and elemental analysis. The ³¹P{¹H} NMR spectra show that among compounds 7–9 containing 2‐, 3‐, and 4‐aminopyridinyl moieties, respectively, the shielding order of the P atom decreases as 7 > 9 > 8 . Also, the structure of compound 7 was determined by X‐ray crystallography. In this structure, repeated noncentrosymmetric dimers are formed by two strong intermolecular N(1)‐H(1N)…N(2) and N(3)‐H(3N)…O(1) hydrogen bonds. Taking into account weak intermolecular C(17)‐H(17C)…N(4), C(17)‐H(17E)…N(4), C(2)‐H(2A)…O(2), and also weak aromatic C—H…C interactions, a three‐dimensional polymeric chain is created in the crystalline network. The density functional theory calculations at B3LYP, B3PW91, and M06 levels using the 6–31+G** basis set were in good agreement with the X‐ray crystallography data.     

Design and tailoring of one-dimensional ZnO nanomaterials for photocatalytic degradation of organic dyes: a review

Research on Chemical Intermediates - Photocatalysis using semiconductors has emerged as a promising wastewater treatment process to overcome the major challenges faced by conventional technologies....     

4-(4′-Diamino-di-phenyl)-sulfone supported on hollow magnetic mesoporous Fe3O4@SiO2 NPs: As a reusable and efficient catalyst for the synthesis of ethyl 2-amino-5,10-dihydro-5,10-dioxo-4-phenyl-4H benzo[g]chromene-3-carboxylates

4-(4′-diamino-di-phenyl)-sulfone supported on hollow magnetic mesoporous (HMMS) Fe₃O₄@SiO₂ NPs has been used as a novel and efficient catalyst in the preparation of ethyl 2-amino-5,10-dihydro-5,10-dioxo-4-phenyl-4H benzo[g]chromene-3-carboxylates by a simple one-pot three-component reaction of aldehydes, ethyl cyanoacetate and 2-hydroxynaphthalene-1,4-dione under reflux conditions in ethanol. Wide range of products, excellent yields in short times, reusability of the catalyst, low catalyst loading and environmental benignity are some of the important features of this protocol.     

Application of the Generalized Differential Quadrature Method in Solving Burgers'Equations

The aim of this paper is to obtain numerical solutions of the one-dimensional, two-dimensional and coupled Burgers' equations through the generalized differential quadrature method (GDQM). The polynomial-based differential quadrature (PDQ) method is employed and the obtained system of ordinary differential equations is solved via the total variation diminishing Runge-Kutta (TVD-RK) method. The numerical solutions are satisfactorily coincident with
the exact solutions. The method can compete against the methods applied in the literature.     

The influence of gas flow rate on the structural,mechanical, optical and wettability of diamond-like carbon thin films

In this research, diamond-like carbon (DLC) thin films were deposited on silicon substrates by radio-frequency plasma enhanced chemical vapor deposition method using gas mixture of CH₄ and Ar. The effect of different CH₄/Ar gas ratio on the structure, refractive index, transmission and hardness of the DLC thin films were investigated by means of Raman spectroscopy, ellipsometry, Fourier transform Infrared Spectroscopy and nano-indentation methods, respectively. Nuclear resonant reaction analysis was used to measure the amount of hydrogen and carbon in the thin films. Furthermore, wettability of the thin films was achieved by measuring of water contact angle (WCA). The results indicated that the structural properties of the diamond-like carbon thin films are strongly dependent on the composition of gas mixture. Based on ellipsometry results, refractive index of the thin films varied in the range of 1.89–2.06 at 550 nm. FTIR results determined that deposition of DLC thin films on silicon substrate led to an increase of the light transmission in IR region and these films have the potential to be used in silicon optics as the antireflective coatings in this region. Nano-indentation analysis showed that the thin films hardness changed in the range of 7.5–11 GPa. On the other hand hydrogen content and fraction of C?H bonds in the samples increased by an increase in the gas ratio of CH₄/Ar. Also, WCA measurements indicated that WCA for thin films with gas ratio of 3/7 is the most and equal to 79°.