A new approach to large deflection analysis of heated sandwich plates

This paper represents non-linear analysis of sandwich plates under thermal loading in which a new approach is followed. Analysis of rectangular sandwich plates has been carried out in detail. Numerical results have been computed and compared with other known results.

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Sommario Questo lavoro illustra l'analisi non lineare delle piastre sandwich sotto carico termico seguendo un nuovo approccio. Si è svolta in dettaglio l'analisi delle piastre rettangolari calcolando valori numerici e paragonandoli con risultati precedentemente noti.

     

On a generalised viscosity equation for polymer solutions

Based on the AFVS concept, a simple equation to predict the viscosity behaviour of polymer solutions is proposed in the following form $$(\ln \eta _r )^{ - 1} = \frac{\alpha }{{\tilde c}} + \delta .$$ This has been verified by comparison with experimental data. The equation appears to have a far more general validity as it appears to correlate the data for a large variety of binary systems including suspensions, liquid mixtures etc.     

Solvent free,palladium catalyzed highly facile synthesis of diaryl disulfides from aryl thiols

An efficient solvent free Pd(pCH₂S)₂dba catalyzed green-chemical strategy for the synthesis of diaryl disulfides from aryl thiols in moderate to excellent yield is reported. Variety of diaryl disulfides were synthesized. The catalyst is recyclable up to four cycles.     

Computational Exploration of Mechanistic Avenues in Metal-Free CO2 Reduction to CO by Disilyne Bisphosphine Adduct and Phosphonium Silaylide

Recent years have seen a growing interest in metal-free CO₂ activation by silylenes, silylones, and silanones. However, compared to mononuclear silicon species, CO₂ reduction mediated by dinuclear silicon compounds, especially disilynes, has been less explored. We have carried out extensive computational investigations to explore the mechanistic avenues in CO₂ reduction to CO by donor-stabilized disilyne bisphosphine adduct ( R1^M ) and phosphonium silaylide ( R2 ) using density functional theory calculations. Theoretical calculations suggest that R1^M exhibits donor-stabilized bis(silylene) bonding features with unusual Si−Si multiple bonding. Various modes of CO₂ coordination to R1^M have been investigated and the coordination of CO₂ by the carbon center to R1^M is found to be kinetically more facile than that by oxygen involving only one or both the silicon centers. Both the theoretically predicted reaction mechanisms of R1^M and R2 -mediated CO₂ reduction reveal the crucial role of silicon-centered lone pairs in CO₂ activations and generation of key intermediates possessing enormous strain in the Si−C−O ring, which plays the pivotal role in CO extrusion.     

Two-dimensional Covalent Organic Frameworks for Electrochromic Switching

The electrochromic materials have received immense attention for the fabrication of smart optoelectronic devices. The alteration of the redox states of the electroactive functionalities results in the color change in response to electrochemical potential. Even though transition metal oxides, redox-active small organic molecules, conducting polymers, and metallopolymers are known for electrochromism, advanced materials demonstrating multicolor switching with fast response time and high durability are of increasing demand. Recently, two-dimensional covalent organic frameworks (2D COFs) have been demonstrated as electrochromic materials due to their tunable redox functionalities with highly ordered structure and large specific surface area facilitating fast ion transport. Herein, we have discussed the mechanistic insights of electrochromism in 2D COFs and their structure-property relationship in electrochromic performance. Furthermore, the state-of-the-art knowledge for developing the electrochromic 2D COFs and their potential application in next-generation display devices are highlighted.     

Temperature-Dependent Photoluminescence of Hexafluorobenzene-Intercalated Phenethylammonium Tin Iodide 2D Perovskite

Tin halide perovskites are potential alternatives of lead halide perovskites. However, the easy oxidation of Sn²⁺ to Sn⁴⁺ brings in a challenge. Recently, layered two-dimensional hybrid tin halide perovskites have been shown to partially resist the oxidation process because of the presence of hydrophobic organic molecules. Consequently, such layered hybrid perovskites are being explored for optoelectronic applications. The optical properties of layered tin halide perovskites depend on the interlayer separation and the dielectric mismatch between the organic and inorganic layers. Intercalation (insertion) of a molecular species between the layers modifies the interlayer interactions affecting the optical properties of layered hybrid perovskites. We investigated the effect of hexafluorobenzene (HFB) intercalation in phenethylammonium tin iodide [(PEA)₂SnI₄] using temperature-dependent (6 K to 300 K) photoluminescence (PL). HFB intercalation increases the bandgap. A strong PL quenching is observed in pristine (PEA)₂SnI₄ below 150 K, probably because of the presence of non-emissive states. HFB intercalation suppresses the influence of such non-emissive states resulting in an increase in PL intensity at the cryogenic temperatures. Our results highlight that a simple molecular intercalation (non-covalent interaction) into layered hybrid perovskites can significantly tailor the electronic and optical properties.     

Efficient and reusable Cu (II)-metalated silica-based inorganic-organic hybrid catalyst for dye degradation

An efficient silica-based inorganic-organic hybrid was synthesized by using 3-(2-aminoethylamino)propyltrimethoxylsilane as linker and 2-Quinolinecarboxaldehyde for Schiff's base formation which was further coordinated by Cu (II) chloride. The hybrid was characterized by relevant techniques, i.e., FT-IR, DRUV-Vis, SEM, EDX, ICP-AES, TGA and EPR technique which support its formation. The synthesized hybrid material was successfully used as heterogeneous catalyst for degrading Reactive Black-5 (RB-5), a non-biodegradable diazo dye. The degradation mechanism follows advanced oxidation technique utilizing hydrogen peroxide as an environmentally amiable green oxidant; where the hybrid catalyst decomposes H₂O₂ to generate ·OH free radicals. Effects of dye concentration, H₂O₂ concentration and temperature variation on dye degradation process were studied and best reaction conditions for maximum degradation of RB-5 were also worked out. The catalyst showed 87% dye degradation in 130 ?min at best reaction conditions. Easy separation, reusability and efficient dye degradation ability of the catalyst are the motivating factors for the development of such hybrid material for solving critical environmental issues.     

Macromolecules assessment from spent biomass during phycoremediation of pollutants from coke-oven wastewater: A prospective approach for production of value added products

Three cyanobacterial and microalgal cultures such as consortium of Leptolyngbya sp. and Planktothrix sp. (Type I), Tetraspora sp. NITD 18 (Type II), and consortium of Chlorella sp. and Synechococcus sp. (type III) were chosen for the growth in both BG-11 and synthetic coke-oven wastewater (STCW). Maximum productivities of protein (75.63 (mg/L)/day, lipid (13.96 (mg/L)/day) were obtained in BG-11 medium for culture type II and that for carbohydrate (86.25 (mg/L)/day) was obtained with Type I. However, in STCW, maximum productivities were obtained as carbohydrate: 75.55 (mg/L)/day (Type III), protein: 57.67 (mg/L)/day (Type III), and lipid: 12.51 (mg/L)/day (Type I). Maximum yield was obtained as follows: carbohydrate - 146.47 mg/g and 122.26 mg/g (Type II), protein - 435.24 mg/g and 537.05 mg/g (Type II), and lipid - 111.45 mg/g and 217.47 mg/g (Type I) in BG-11 and STCW solutions, respectively. Artificial Neural Network-Genetic algorithm (ANN-GA) was used for modeling and optimization to get maximum outputs. The aim is selection of the suitable culture for the production of macromolecules under naïve and stressed environment.     

Extended Corannulenes: Aromatic Bowl/Sheet Hybridization

Among sheet/sheet polynuclear aromatic hydrocarbon (PAH) hybrids, a buckybowl–graphene hybrid has been used as a model to explore the effects of physical properties of PAHs with distinct planar and bowl regions. Activation of a C(Ar)? F bond was used to synthesize this corannulene/graphenic hybrid. Photophysical and voltammetric studies together with high‐level computations revealed curvature and extended π‐effects on the properties of these materials.