Highly Selective and Sensitive Membrane Sensors for Copper(II) Ion Based on a New Benzo‐Substituted Macrocyclic Diamide 6,7,8,9,10‐Hexahydro‐2H‐1,13,4,7,10‐benzodioxatriazacyclopentadecine‐3,11(4H,12H)‐dione

Novel PVC membrane (PME) and coated graphite (CGE) Cu²⁺‐selective electrodes based on 5,6,7,8,9,10‐hexahydro‐2H‐1,13,4,7,10‐benzodioxatriazacyclopentadecine‐3,11(4H,12H)‐dione are prepared. The electrodes reveal a Nernstian behavior over wide Cu²⁺ ion concentration ranges (1.0×10^?7–1.0×10^?1 M for PME and 1.0×10^?8–1.0×10^?1 M for CGE) with very low limits of detection (7.8×10^?8 M for PME and 9.1×10^?9 M for CGE). The potentiometric responses are independent of the pH of the test solutions in the pH range 2.7–6.2. The proposed electrodes possess very good selectivities for Cu²⁺ over a wide variety of the cations including alkali, alkaline earth, transitions and heavy metal ions. The practical utility of the proposed electrodes have been demonstrated by their use in the study of interactions between copper ions and human growth hormone (hGH) in biological systems, potentiometric titration of copper with EDTA and determination of copper content of a sheep blood serum sample and some other real samples.     

Non-isothermal degradation kinetics of MMA-St copolymer and EPS lost foams

Methylmethacrylate-styrene (MMA-St) random copolymer was synthesized by suspension copolymerization. The thermal degradation of MMA-St copolymer and EPS lost foams was studied by non-isothermal thermal gravimetric analysis under nitrogen purge. Thermal decomposition behavior of MMA-St copolymer lost foam was examined and compared with EPS. It was found that EPS foam starts to decompose at higher temperatures than MMA-St copolymer foam in all heating rates. The apparent activation energy was calculated by the Flynn-Wall-Ozawa method. It has been concluded that the model fitting methods unable to reveal the complexity of the pyrolysis process and the model-free methods can be suggested as a reliable way of determining the kinetic parameters.     

Thermodynamic features of perfectly crystalline poly(3‐hexylthiophene) based on Flory's relation

Poly(3‐hexylthiophene) (P3HT) as a conjugated polymer has many electrical and photovoltaic applications. However, reliable values for the equilibrium melting temperature ( ${T°}_m$) and for the enthalpy of fusion of a perfect P3HT crystal ( ${\Delta H°}_m$) are still in doubt. In the published works, ${\Delta H°}_m$ ranges from 33 to 99 J/g. Here, the melting point of P3HT in P3HT‐diluent mixtures is measured with changing the diluent concentration. By satisfying the requirements of Flory relation, “working with the same polymer crystals” and “working in the equilibrium state,” usually neglected in the literature, a reliable value of ${\Delta H°}_m$ = 83 ± 2 J/g is obtained. The reported values for ${T°}_m$ of P3HT are also in a wide range, 260?300 °C. In this work, accurate applying of the Hoffman‐Weeks relation, against the effects of lamellar thickening, yields ${T°}_m$ = 272 ± 2 °C rather than 300 ± 2°C reported in the literature. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 431–437     

An Anonymous Surveying Protocol via Greenberger-Horne-Zeilinger States

A new experimentally feasible anonymous survey protocol with authentication using Greenberger-Horne-Zeilinger (GHZ) entangled states is proposed. In this protocol, a chief executive officer (CEO) of a firm or company is trying to find out the effect of a possible action. In order to prepare a fair voting, the CEO would like to make an anonymous survey and is also interested in the total action for the whole company and he doesn’t want to have a partial estimate for each department. In our proposal, there are two voters, Alice and Bob, voting on a question with a response of either ”yes” or ”no” and a tallyman, whose responsibility is to determine whether they have cast the same vote or not. In the proposed protocol the total response of the voters is calculated without revealing the actual votes of the voters.     

4E analysis and tri-objective optimization of a triple-pressure combined cycle power plant with combustion chamber steam injection to control NOx emission

This article presents a novel triple-pressure combined cycle power plant (CCPP) with a heat recovery steam generator (HRSG) configured with heat exchangers of multiple pressure levels, same as the real case. In addition, combustion chamber steam injection is added to the top cycle in order to reduce hazardous emissions. The research investigates energy, exergy, economic, and environmental aspects of the system to initiate sustainable development in said areas. A thorough parametric study is carried out to evaluate the effects of steam injection and other decision variable on emissions and system performance. Then, the total cost rate and the CO₂ index are minimized while maximizing the second law efficiency via a tri-objective optimization using the genetic algorithm. The outcome of the economic analysis is that the HRSG has the maximum total cost rate among all the components, namely 0.1673 $/s. The environmental impact  assessments indicate that the CO₂ and NO emission has considerable molar fractions of 0.035 and 6.88?×?10^?4, respectively. As a result of the tri-objective optimization, a 3D Pareto Frontier is presented, which pointed out the maximum attainable exergy efficiency is 50.32%, as well as the minimum total cost rates of 8.04 $/s and CO₂ index of 0.34 kg/kWh. Finally, the scatter distribution of major decision variables revealed the optimum range of decision variables in which the optimum points of the Pareto Frontier are obtained. Accordingly, the scatter distribution showed that 46 kg s^?1 is the optimum value for steam injection flow rate in terms of efficiency, cost and emission optimization.

     

Double/single phase segregation and vertical stratification induced by crystallization in all‐crystalline tri/diblock copolymers and homopolymer blends of poly(3‐hexylthiophene) and poly(ethylene glycol)

Distinct stratified and non‐stratified morphologies were developed in poly(3‐hexylthiophene) (P3HT) and poly(ethylene glycol) (PEG)‐based homopolymer blends and diblock and triblock copolymer systems. By applying X‐ray photoelectron spectroscopy, only a double‐percolation mechanism including assembling of P3HT chains into the nanofibers in solution aging process with a marginal solvent like p‐xylene as well as crystallization of PEG phase in the cast thin films resulted in vertical stratification and networked fibrils. In cast thin films whose PEG phase, due to low molecular weight or being constrained between two rigid P3HT blocks in triblock copolymers was not crystallized, a non‐stratified discrete fibrillar morphology was acquired. Crystallization of PEGs in the thin films mainly participated in networking and expelling pre‐organized P3HT fibrils to the film surface. By performing the solution aging step in a good solvent such as o‐dichlorobenzene, the P3HTs remained in a coily‐like conformation, and casting the corresponding thin films reflected the non‐stratified discrete granular and featureless morphologies. Assembling the P3HT chains in the presence of PEG phase in cast films at most led to the low‐crystalline granules instead of highly crystalline nanofibrils. No significant crystallization in either homopolymer blends or block copolymer systems conduced to a featureless morphology with homogeneous distribution of existed materials. The surface morphology and ordering in various morphologies were studied employing atomic force microscopy, grazing incidence X‐ray diffraction, and ultraviolet–visible analyses. Copyright © 2016 John Wiley & Sons, Ltd.     

Novel potentiometric membrane sensor for the determination of trace amounts of chromium(III) ions.

A plasticized Cr3+ ion sensor by incorporating 2,3,8,9-tetraphenyl-1,4,7,10-tetraazacyclododeca-1,3,7,9-tetraene (TTCT) ionophore exhibits a good potentiometric response for Cr3+ over a wide concentration range (1.0 x 10(-6)-1.0 x 10(-1) M) with a slope of 19.5 mV per decade. The sensor response is stable for at least three months. Good selectivity for Cr3+ in comparison with alkali, alkaline earth, transition and heavy metal ions, and minimal interference are caused by Li+, Na+, K+, Co2+, Hg2+, Ca2+, Pb2+ and Zn2+ ions, which are known to interfere with other chromium membrane sensors. The TTCT-based electrode shows a fast response time (15 s), and can be used in aqueous solutions of pH 3-5.5. The proposed sensor was used for the potentiometric titration of Cr3+ with EDTA and for a direct potentiometric determination of Cr3+ content in environmental samples.     

One-step, synthesis of Hantzsch esters and polyhydroquinoline derivatives using new organocatalyst

<正>Herein we report an efficient organocatalyst for the multicomponent Hantzsch reaction under mild condition.The product easily isolated by simple filtration and catalyst can be recovered.     

Boundary stabilization of vibration of nonlocal micropolar elastic media

In this paper, we study the stabilization problem of vibration of linearized three-dimensional nonlocal micropolar elasticity. For this purpose, we need to demonstrate the well-posedness of the system of equations governing the vibration of three-dimensional nonlocal micropolar media for both forced (i.e. with boundary feedback) and unforced cases. We assume the non-homogeneous system of equations for the unforced (uncontrolled) case to establish the well-posedness. It should be pointed out that the well-posedness of the evolution equations in micropolar case has been studied by many authors; but, the well-posedness in the nonlocal micropolar is an open problem. Our tools in well-posedness analysis are the semigroup techniques. Afterwards, we pursue the stabilization problem and show that the vibration of the nonlocal micropolar elastic media will be eventually dissipated under boundary feedback actions consisting of stress and couple stress feedback laws. These control laws are simple, linear and can be easily implemented in practical applications. The stabilization proof is accomplished using Lyapunov stability and LaSalle’s invariant set theorems.