Synthesis of spiro[5.4]decenones and their transformation into bicyclo[4.4]deca-1,4-dien-3-ones by domino "elimination- double-Wagner-Meerwein-rearrangement" reactions

The [3+3] cyclization of 1,3-bis-silyl enol ethers with 1,1-diacylcyclopentanes allows a convenient synthesis of spiro[5.4]decenones. Treatment of these compounds with trifluoroacetic acid (TFA) afforded a great variety of bicyclo[4.4.0]deca-1,4-dien-3-ones containing an angular alkyl group. This core structure occurs in a number of pharmacologically relevant natural products.     

Adsorption of nitrogen dioxide on C30B15N15 heterofullerene: AIM and NBO study via DFT

Adsorption of nitrogen dioxide on the exterior surface of C₃₀B₁₅N₁₅ through B atom of adsorbent is studied using the DFT-B3LYP/6-31G^* level. Independent to the orientation, the NO₂ molecule presents strong chemisorption with large charge transfer from C₃₀B₁₅N₁₅ to adsorbed gas. NBO (natural electron configuration of adsorbing B atom), AIM analysis and spin density distributions indicate that the chemisorption of NO₂ on the C₃₀B₁₅N₁₅ in all studied complexes are covalent in nature.     

Empirical correlations development for heat transfer and friction factor of a solar rectangular air passage with spherical-shaped turbulence promoters

Journal of Thermal Analysis and Calorimetry - A study was conducted to enhance the thermo-hydraulic performance of a rectangular solar air passage with integrated spherical-shaped turbulence...     

Solving Nonlinear p-Adic Pseudo-differential Equations: Combining the Wavelet Basis with the Schauder Fixed Point Theorem

We consider the pointwise convergence problem for the solution of Schrödinger-type equations along directions determined by a given compact subset of the real line. This problem contains Carleson’s problem as the simplest case and was studied in general by Cho et al. We extend their result from the case of the classical Schrödinger equation to a class of equations which includes the fractional Schrödinger equations. To achieve this, we significantly simplify their proof by completely avoiding a time localization argument.     

Separation of BTEX compounds (benzene,toluene, ethylbenzene and xylenes) from aqueous solutions using adsorption process

A commercial synthetic zeolite (Na-ZSM-5) was modified with an organic surfactant, HDTMA-Br. Then both unmodified and modified zeolite (SMZ-100) were tested to adsorb Benzene, Toluene, Ethylbenzene and Xylene (BTEX) compounds from water solution. Adsorption tests were done in batch conditions at the ambient temperature (20?°C) and pressure. Adsorbents were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N₂ adsorption-desorption isotherms and field emission scanning electron microscopy (FE-SEM) and characterization results proved the existence of surfactant on the surface of the adsorbent. In all cases, the modified zeolite sample, because of increasing the hydrophobicity of its surface, exhibited higher adsorption capacity in comparison with unmodified zeolite. Also, for each adsorbent, the adsorption capacity follows the order: E?>?X?>?T?>?B. In equilibrium experiments, Langmuir isotherm model fitted the equilibrium data better than the Freundlich model. In kinetic experiments, the pseudo-second order model described the kinetic data better than the other models.     

Tuning the electronic‐optical properties of porphyrin‐like porous C24N24 fullerene with (Li3O)n = (1–5) decoration. A computational study

Using DFT methods, the electronic properties and the first hyperpolarizabilities of porphyrin‐like porous C₂₄N₂₄ fullerene decorated with (Li₃O)_{n = (1–5)} have been systematically investigated. It is found that Li₃O molecules can effectively be adsorbed over N4 cavities of C₂₄N₂₄ with high interaction energies. This interaction is found to narrow the HOMO‐LUMO gap and work function values of C₂₄N₂₄. Thus its electronic properties are strongly sensitive to interaction with the Li₃O molecules. Indeed, compared with the sole parent C₂₄N₂₄ fullerene, (Li₃O)_{n = (1–5)}@C₂₄N₂₄ possess large first hyperpolarizabilities (β₀ ). Obviously, the Li₃O superalkali chemisorbed over C₂₄N₂₄ fullerene exhibit not only excellent stability but also large first hyperpolarizability. Therefore, they are expected to be potential innovative candidates for excellent electro‐optical materials.     

SPH-based numerical treatment of the interfacial interaction of flow with porous media

In this paper, the macroscopic equations of mass and momentum are developed and discretized based on the smoothed particle hydrodynamics (SPH) formulation for the interaction at an interface of flow with porous media. The theoretical background of flow through porous media is investigated to highlight the key constraints that should be satisfied, particularly at the interface between the porous media flow and the overlying free flow. The study aims to investigate the derivation of the porous flow equations, computation of the porosity, and treatment of the interfacial boundary layer. It addresses weak assumptions that are commonly adopted for interfacial flow simulation in particle-based methods. As support to the theoretical analysis, a two-dimensional weakly compressible SPH model is developed based on the proposed interfacial treatment. The equations in this model are written in terms of the intrinsic averages and in the Lagrangian form. The effect of particle volume change due to the spatial change of porosity is taken into account, and the extra stress terms in the momentum equation are approximated by using Ergun's equation and the subparticle scale model to represent the drag and turbulence effects, respectively. Four benchmark test cases covering a range of flow scenarios are simulated to examine the influence of the porous boundary on the internal, interface, and external flows. The capacity of the modified SPH model to predict velocity distributions and water surface behavior is fully examined with a focus on the flow conditions at the interfacial boundary between the overlying free flow and the underlying porous media.