Simple sonochemical synthesis and characterization of HgSe nanoparticles

Mercury selenide (HgSe) nanostructures were synthesized via a sonochemical method based on the reaction between HgCl(2), SeCl(4) and hydrazine hydrate (N(2)H(4)·H(2)O) in water, in presence of various capping agents. The effects of preparation parameters such as: the kind of capping agent and its amount, ultrasonic power, reaction time and temperature were investigated. It was found that morphology, particle size and phase of the products could be greatly affected by these parameters. HgSe nanostructures were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), photoluminescence spectroscopy (PL) and X-ray energy dispersive spectroscopy (EDS).     

Application of perforated sheets to improve the efficiency of reactive profiled noise barriers

The scope of this paper is to study the performance of noise barriers treated with different diffusers with/without a perforated sheet. We investigated the barrier insertion loss using a 2D boundary element method (BEM). To obtain a better depth sequence, a Random Sequence Diffuser (RSD) was designed. The results clearly showed that employing a "RSD" instead of the most popular Schroeder diffusers (Quadratic Residue Diffuser and Primitive Root Diffuser) increased the acoustic performance. We also found that the diffuser performance improved by treating the diffuser with perforated sheets either on the top surface or inside the wells. The addition of these perforated sheets inside the "RSD" (barrier model "RPI2") improved the performance by 3.59 dB (A).     

A new force field for the adsorption of H2, O2, N2, CO,H2O,and H2S gases on alkali doped carbon nanotubes

The main goal of this work is the generation of a new force field data set to the interaction of several gases such as H₂, O₂, N₂, CO, H₂O, and H₂S with alkali cation-doped carbon nanotubes (CNTs) using ab initio calculations at the MP2(full)/6-311++G(d,p) level of theory. Different alkali cations including Li⁺, Na⁺_, K⁺ and Cs⁺ were used to dope in the CNT. The calculated potential energy curve for the interaction of each gas molecule with each alkali cation-doped CNTs was fitted to an analytical potential function to obtain the parameters of the potential function. A modified Morse potential function was selected for the fitting in which the electrostatic interactions has been accounted by adding the β/r term to the Morse potential. The accuracy of the calculated force field was checked via Grand Canonical Monte Carlo (GCMC) simulation of the H₂ adsorption on Li-doped graphite and Li-doped CNT. The results of these simulations were compared with the experimental measurements and the closeness of the simulation results with the experimental data indicated the accuracy of the proposed force field. The main merit of this work is the derivation of a specific force field for interaction of each of six gases with four alkali cation-doped CNT, which can be used in molecular simulation of these 24 of systems. The simulation results showed the increase of the H₂ adsorption capacity of nanotube and graphite up to 50% and 10%, respectively, due to the insertion of Li ions.     

A potentiometeric study of protonation and complex formation of xylenol orange with alkaline earth and aluminum ions

Xylenol orange (XO) is one of the complexometric indicators, that can bind to metal cations at both their amino and acidic groups. In this study the protonation constants and distribution diagrams of XO were studied pH-metrically, and the corresponding six protonation constants were calculated. The complex formation between XO (L) and alkaline earth ions (M) was investigated and the formation constants of the resulting complexes ML, MHL, M(2)L and M(2)HL were determined. The stabilities of both ML and M(2)L complexes were found to vary in the order Mg(2+)> Ca(2+)> Sr(2+)> Ba(2+). Studying the complex formation between Al(3+) ion (M) and XO (L), it was observed that four complexed species with stoichiometries ML, ML(2), MHL and MH(2)L could be formed in solution. It was also found that the Al L(2) complex can act as a chelating agent for further complexation with two cations other than Al(3+) ion (i.e. Ba, L, Al, L, Ba, Mg, L, Al, L, Mg, and Mg, L, Al, L, Ba). The formation constants of the resulting mixed complexes were determined and their distribution diagrams were investigated.     

The kinetic and thermodynamic study of the removal of Cr(VI) ion from aqueous solution by human hair waste

The removal of Cr(VI) ions from aqueous solution by human hair waste is investigated by using UV–Vis spectrophotometer technique. The morphological analysis of the human hair was also investigated by the scanning electron microscopy, Fourier transforms infrared spectroscopy and X-ray photoelectron spectroscopy. The influence of various physicochemical effective parameters such as pH, ionic strength, adsorbent amount, contact time, initial concentration of metal ion on removal of Cr(VI) ions by human hair process was also studied. The optimum conditions for this adsorption process were obtained at pH = 2 and contact time of 150 min while the highest Cr(VI) uptake is recorded for 0.5 g of the adsorbent per 100 ml of solution. Three isotherms models including Langmuir, Freundlich and Temkin were applied to describe the equilibrium data. It was found that the experimental data were well described by Freundlich isothermal model. The maximum adsorption capacity was found to be 11.64 mg g^?1.The thermodynamic study data showed that the adsorption process of Cr(VI) on human hair is an endothermic, spontaneous and physisorption reaction. The kinetics of the adsorption process was studied using three kinetics models including Lagergren-first-order, pseudo-second-order and Elovich model. The obtained data are indicated that the adsorption processes of Cr(VI) over human hair could be described by the pseudo-second-order kinetic model.     

Synthesis of new indolylpyrrole derivatives via a four-component domino reaction between arylglyoxals,acetylacetone, indole and aliphatic amines in aqueous media

A novel synthesis of indolylpyrrole derivatives is described by a four-component domino reaction between arylglyoxals, acetylacetone, indole and aliphatic amines in water as solvent at 60?°C without using any catalyst or promoter. The FT-IR, ¹H NMR, ¹³C NMR spectral and elemental analysis confirm the structures of the products.     

The effect of curvature of Li-doped polycyclic hydrocarbon on its interaction energy with H<Subscript>2</Subscript> and H<Subscript>2</Subscript>O: DF-SAPT (DFT) calculation

In this work, the interaction of three Li⁺-doped polycyclic hydrocarbons (Li⁺-DPH) with H₂ and H₂O was calculated to investigate the effect of curvature of substrate on the interaction energy (E_int). For this purpose, the E_int and its decomposed energy components (electrostatic (E_elec), exchange (E_exch), induction (E_ind), and dispersion energy (E_disp)) were calculated using DF-SAPT (DFT) methodology for the selected systems (Li⁺-(3,3) carbon nanotube (Li⁺-CNT33), Li⁺-(6,6) carbon nanotube (Li⁺-CNT66), and Li⁺-graphene). According to the results, E_int does not change significantly with curvature for the interaction between both H₂ and H₂O gases and the selected Li⁺-DPH. Since the variation of the E_int with the curvature of Li⁺-DPH is not significant, the selection of a planar Li⁺-DPH is a trustworthy model to develop a general force field for describing the interaction between a Li⁺-DPH and adsorbed gases. The results reveal that, in the case of the H₂, the components E_elect, E_exch, E_ind, and E_disp have shown a decreasing trend with Li⁺-DPH’s curvature decrement. However, for the H₂O, E_elect, E_exch, and E_ind decrease from the Li⁺-CNT33 to the Li⁺-CNT66 while they increase from the Li⁺-CNT66 to the Li⁺-graphene. In this case, the E_disp increases with a decrease of the curvature of Li⁺-DPH. Finally, it can be seen that although the variation of the E_int with the curvature of Li⁺-DPH is not significant, the variation trend of the interaction energy components and the amount of variation depend on the gas molecule and in some cases are not negligible.     

[Omim][NO3], a Green and Base-Free Medium for One-Pot Synthesis of Benzothiazinones at Room Temperature

A general and efficient room-temperature procedure is developed for high-yield synthesis of 2H-benzo[b][1,4]thiazin-3(4H)-one derivatives in one pot from the reaction of 2-aminothiophenols with 2-bromoalkanoates in ionic liquid [bmim]NO₃ without the use of any catalyst, base, or additive. Products were obtained in good yields by simple extraction with Et₂O followed by evaporation of the volatile contents and recrystallization from Et₂O. The ionic liquid was recycled and reused in the next reaction without the loss of its activity.     

On simultaneous triangularization of collections of compact operators

In this paper we consider collections of compact (resp. C_p class) operators on arbitrary Banach (resp. Hilbert) spaces. For a subring R of reals, it is proved that an R-algebra of compact operators with spectra in R on an arbitrary Banach space is triangularizable if and only if every member of the algebra is triangularizable. It is proved that every triangularizability result on certain collections, e.g., semigroups, of compact operators on a complex Banach (resp. Hilbert) space gives rise to its counterpart on a real Banach (resp. Hilbert) space. We use our main results to present new proofs as well as extensions of certain classical theorems (e.g., those due to Kolchin, McCoy, and others) on arbitrary Banach (resp. Hilbert) spaces.