Sonochemical synthesis and characterization of Cu2HgI4 nanostructures photocatalyst with enhanced visible light photocatalytic ability

These days, an important concern in water contamination is the remaining dyes from various sources (for instance, dye and dye intermediates industries, pulp and paper industries, textile industries, craft bleaching industries, tannery, and pharmaceutical industries, etc.), and a broad range of persistent organic contamination has been entered to the wastewater treatment systems or natural water supplies. Indeed, it is extremely hazardous and toxic to the living organism. Therefore, it is necessary to remove these organic pollutants before releasing them into the environment. Photocatalysis is a quickly growing technology for sewage procedures. For this purpose, Cu₂HgI₄ nanostructures were prepared via facile, and cost-effective sonochemical method. The effect of varied circumstances, such as various surfactants, sonication power, and sonication time was considered on the crystallinity, structure, shape, and particle size of products. Cu₂HgI₄ possesses a suitable bandgap (2.2 eV) in the visible area. The photocatalytic performance of the Cu₂HgI₄ was surveyed for the elimination of various organic dyes under visible radiation and exposed that this compound could degrade and remove methyl orange about 94.2% in an acidic medium after 160 min under visible light. Besides, the result showed that various parameters, including, pH, dye concentration, types of dyes, catalyst dosages, and time of irradiation affected the photocatalytic efficiency.     

Green synthesis and characterization of Tb-Fe-O-Cu ceramic nanocomposite and its application in simultaneous electrochemical sensing of zinc,cadmium and lead

In this work, a green technique for preparing TbFeO₃/CuO was reported by employing Crataegus and Lantana Camara leaves as fuel and alkalizing agents, respectively. The new sensor based on the perovskite-type nanocomposite was employed as a sensitive and selective platform to detect Pb(II), Zn(II) and Cd(II) simultaneously. TbFeO₃/CuO/Carbon paste electrode (CPE) exhibited a large specific surface area and great electrical conductivity, which enhanced electron transport in the electrochemical process considerably. Moreover, square wave anodic stripping voltammetry (SWASV) was used for the investigation of some factors influencing the sensor sensitivity like pH, modifier concentration, as well as accumulation time and potential. Therefore, the low detection limit (LOD) and a wide linear range were obtained at optimum conditions. In this study, a linear range between 0.9 and 110 µg/L for three ions and LOD of 0.48, 0.29 and 0.12 for zinc, cadmium and lead were achieved, respectively. Moreover, TbFeO₃/CuO/CPE was employed to detect zinc, cadmium and lead ions simultaneously in the real samples so that the results have shown consistency with a standard inductively coupled plasma (ICP).     

Dinuclear gold (I)-di-N-heterocyclic carbene complexes: syntheses,structure, density functional theory calculation and photoluminescence study

The synthesis and characterizations for a series of dinuclear gold (I)-di-NHC complexes, 1–8 through the trans-metalation method of their respective silver (I)-di-NHC complexes, i–viii are reported (where NHC = N-heterocyclic carbene). The successful complexation of a series of unusual non-symmetrical and symmetrical di-NHC ligands, 3,3'-(ethane-1,2-diyl)-1-alkylbenzimidazolium-1'-butylbenzimidazolium (with alkyl = methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, benzyl) with the gold (I) ions are suggested by elemental analysis, Fourier transform-infrared, ¹H- and ¹³C-NMR data. The ¹³C-NMR spectra of 1–8 show a singlet sharp peak in the range of 190.00–192.00 ppm, indicating the presence of a carbene carbon that bonded to the gold (I) ion. From single crystal X-ray diffraction data, the structure of complex 6 with the formula of [di-NHC-Au (I)]₂·2PF₆ is obtained [where NHC = 3,3'-(ethane-1,2-diyl)-1-hexylbenzimidazolium-1'-butylbenzimidazolium]. The photophysical study in solid state of 6 displays an intense photoluminescence with a strong emission maxima, λ_em = 480 nm, upon excitation at 340 nm at room temperature. Interestingly, the emission maximum at 77 K shows a structural character with a strong peak at 410 nm, a medium at 433 nm and a weak at 387 nm, accompanied by a tail band to about 500 nm.     

Multi soliton solutions,M-lump waves and mixed soliton-lump solutions to the awada-Kotera equation in (2+1)-dimensions

In this research paper, the well-known simple Hirota’s method is employed to study the (2+1)-dimensional Sawad-Kotera equation. The logarithmic variable transformation is implemented on the proposed problem to construct the bilinear Hirota form. Based on its bilinear representation, the features of multi soliton solutions, M-lump waves, and the mixed 1-M-lump with one-soliton, and two-soliton solutions are explored. For one M-lump solution, the wave motion in the x and y directions are also studied. To better understand the physical phenomena of the gained solutions, three-dimensional graphics and their corresponding surfaces are also presented.     

Experimental and computational studies of naphthyridine derivatives as corrosion inhibitor for N80 steel in 15% hydrochloric acid

The inhibition effect of three naphthyridine derivatives namely 2-amino-4-(4-methoxyphenyl)-1,8-naphthyridine-3-carbonitrile (ANC-1), 2-amino-4-(4-methylphenyl)-1,8-naphthyridine-3-carbonitrile (ANC-2) and 2-amino-4-(3-nitrophenyl)-1,8-naphthyridine-3-carbonitrile (ANC-3) as corrosion inhibitors for N80 steel in 15% HCl by using gravimetric, electrochemical techniques (EIS and potentiodynamic polarization), SEM, EDX and quantum chemical calculation. The order of inhibition efficiency is ANC-1>ANC-2>ANC-3. Potentiodynamic polarization reveals that these inhibitors are mixed type with predominant cathodic control. Studied inhibitors obey the Langmuir adsorption isotherm. The quantum calculation is in good agreement with experimental results.     

Multiple rogue wave and solitary solutions for the generalized BK equation via Hirota bilinear and SIVP schemes arising in fluid mechanics

The multiple lump solutions method is employed for the purpose of obtaining multiple soliton solutions for the generalized Bogoyavlensky-Konopelchenko(BK) equation. The solutions obtained contain first-order, second-order, and third-order wave solutions. At the critical point,the second-order derivative and Hessian matrix for only one point is investigated, and the lump solution has one maximum value. He's semi-inverse variational principle(SIVP) is also used for the generalized BK equation. Three major cases are studied, based on two different ansatzes using the SIVP. The physical phenomena of the multiple soliton solutions thus obtained are then analyzed and demonstrated in the figures below, using a selection of suitable parameter values.This method should prove extremely useful for further studies of attractive physical phenomena in the fields of heat transfer, fluid dynamics, etc.     

The Application of Fractal Transform and Entropy for Improving Fault Tolerance and Load Balancing in Grid Computing Environments

This paper applies the entropy-based fractal indexing scheme that enables the grid environment for fast indexing and querying. It addresses the issue of fault tolerance and load balancing-based fractal management to make computational grids more effective and reliable. A fractal dimension of a cloud of points gives an estimate of the intrinsic dimensionality of the data in that space. The main drawback of this technique is the long computing time. The main contribution of the suggested work is to investigate the effect of fractal transform by adding R-tree index structure-based entropy to existing grid computing models to obtain a balanced infrastructure with minimal fault. In this regard, the presented work is going to extend the commonly scheduling algorithms that are built based on the physical grid structure to a reduced logical network. The objective of this logical network is to reduce the searching in the grid paths according to arrival time rate and path’s bandwidth with respect to load balance and fault tolerance, respectively. Furthermore, an optimization searching technique is utilized to enhance the grid performance by investigating the optimum number of nodes extracted from the logical grid. The experimental results indicated that the proposed model has better execution time, throughput, makespan, latency, load balancing, and success rate.     

One-bond 1J(15N,H) coupling constants at sp2-hybridized nitrogen of Schiff bases,enaminones and similar compounds: A theoretical study

¹J(¹⁵N,H) coupling constants for enaminones and NH-forms of intramolecularly hydrogen-bonded Schiff bases as model compounds for sp²-hybridized nitrogen atoms are evaluated using density functional theory (DFT) to find the optimal functionals and basis sets. Ammonia is used as a test molecule and its one-bond coupling constant is compared with experiment. A methylamine Schiff base of a truncated molecule of gossypol is used for checking the performance of selected B3LYP, O3LYP, PBE, BHandH, and APFD density functionals and standard, modified, and dedicated basis sets for coupling constants. Both in vacuum and in chloroform, modeled by the simple continuum model of solvent, the modified basis sets predict significantly better the ¹J(¹⁵N,H) value in ammonia and in the methylamine Schiff base of a truncated molecule of gossypol than the standard basis sets. This procure is then used on a broad set of intramolecularly hydrogen-bonded molecules, and a good correlation between calculated and experimental one-bond NH coupling constants is obtained. The ¹J(¹⁵N,H) couplings are slightly overestimated. The calculated data show for hydrogen-bonded NH interatomic distances that the calculated values depend on the NH bond lengths. The shorter the bond lengths, the larger the ¹J(¹⁵N,H). A useful correlation between ¹J(¹⁵N,H) and NH bond length is derived that enables realistic predictions of one-bond NH coupling constants. The calculations reproduce experimentally observed trends for the studied molecules.     

Racemisation in Chemistry and Biology

The two enantiomers of a compound often have profoundly different biological properties and thus their liability to racemisation in aqueous solutions is an important piece of information. The authors reviewed the available data concerning the process of racemisation in vivo, in the presence of biological molecules (e.g., racemase enzymes, serum albumin, cofactors and derivatives) and under purely chemical but aqueous conditions (acid, base and other aqueous systems). Mechanistic studies are described critically in light of reported kinetic data. The types of experimental measurement that can be used to effectively determine rate constants of racemisation in various conditions are discussed and the data they provide is summarised. The proposed origins of enzymatic racemisation are presented and suggest ways to promote the process that are different from processes taking place in bulk water. Experimental and computational studies that provide understanding and quantitative predictions of racemisation risk are also presented.