Fabrication of ZnSe Thin Solid Films on the Cu Substrate and Investigation of Electrochemical,Adhesion and Solar Cell Properties by a New Technique

Russian Journal of Electrochemistry - Zinc selenide has applications in the fabrication of low-cost solar cells and optoelectronic devices. Due to its optical properties and large direct bandgap,...     

Facile fabrication of Zn/Zn5(OH)8Cl2·H2O flower-like nanostructure on the surface of Zn coated with poly (N-methyl pyrrole)

Zn/Zn₅(OH)₈Cl₂·H₂O flower-like nanostructures was electrodeposited on the coated Zn with poly (N-methyl pyrrole) in 0.1 M Zn (NO₃)₂ and 0.1 M KCl solution. The morphology and the structure of the Zn/Zn₅(OH)₈Cl₂·H₂O were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction analysis (XRD). The FT-IR results showed special peaks at 908 and 728 cm⁻¹ related to Zn₅(OH)₈Cl₂·H₂O. The FESEM results indicated that Zn/Zn₅(OH)₈Cl₂·H₂O consists of a flower-like nanostructure and these flower-shaped structures contain many shaped nanopetals with the thickness of 27.8 nm. The XRD result confirmed that the major phase of electrodeposited product in 0.1 M KCl as supporting electrolyte was Zn₅(OH)₈Cl₂·H₂O. The ability of PMPy to create a thin film and the existence of several pores in its matrix act as a mold for the growth of Zn/Zn₅(OH)₈Cl₂·H₂O flower-like nanostructure. The trapping of Cl⁻ and OH⁻ within pores can be considered as the reason for the formation of flowerlike Zn/Zn₅(OH)₈Cl₂·H₂O nanostructures in 0.1 M KCl.     

A spatio-temporal dynamic regression model for extreme wind speeds

This paper presents a hierarchical regression type model for analyzing the dependency of sample extremes on time, space and a covariate effect. The model is based on the assumption that the observations follow independently a generalized extreme value distribution given location, scale and shape parameters. Then a multivariate spatial process is considered to accommodate the association and spatial correlation in the distribution parameters. The mean of the process incorporates the underlying dynamics which is elaborated on the lower stage of hierarchy. Finally, three spatio-temporal dynamic linear models drive independently this mean function to take the variations in the parameters separately into account. In a Bayesian setting, the model structure leads to parallel implementation of the Markov chain Monte Carlo algorithm in a sense that it is less time consuming. Our methodology is applied to the monthly maxima of wind speed with temperature as a covariate for which the relationship is expressed in terms of a penalized spline regression model. The comparison of the proposed model with several simpler ones suggests considerable improvements in wind speed analysis.     

Synthesis and applications of cross-linked poly(diallyldimethyl ammonium chloride) and its derivative copolymers as efficient phase transfer catalyst for nucleophilic substitution reactions

Cross-linked poly(diallyldimethylammonium chloride) and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions. In addition, the effect of hydrophilic-hydrophobic character of the polymers in the nucleophilic reactions was investigated.     

Microchip electrophoresis for specific gene detection of the pathogenic bacteria V. cholerae by circle-to-circle amplification.

We have developed a new method for a fast and precise analysis of circle-to-circle amplification (C2CA) product for specific gene detection by microchip electrophoresis. In this method, we have added a new enzymatic step to the C2CA reaction, which could be carried out isothermally at 37 degrees C. Compared to the original single-stranded DNA, the double-stranded DNA that is produced by this enzymatic reaction is more reliable for analysis by microchip electrophoresis. C2CA product was detected within 55 s with high reproducibility by this method which was successfully applied to the detection of 10-ng genomic DNA of the pathogenic bacteria Vibrio. cholerae within 110 s. Purification was found to be an indispensable step for the analysis of the C2CA product of genomic DNA samples.     

Application of Nanocrystalline Iranian Diatomite in Immobilized Form for Removal of a Textile Dye

The aim of the present investigation was to immobilize nanocrystalline diatomite within calcium alginate matrix for the adsorption of Direct Red23 (DR23) in aqueous media. Scanning electron microscopy (SEM), x-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy were used to characterize the samples. As a result, the adsorption process obeyed pseudo-second-order kinetic model (R² = 0.9934) and Langmuir isotherm model (R² = 0.9732) with a maximum adsorption capacity of 24.10 mg/g. The value of mean free energy (15.81 kJ/mol) demonstrated that the process has been taken place chemically. As the adsorbent dosage increased from 0.5 to 3.0 g/L, the decolorization efficiency (%) increased from 26.0 to 75.5%, respectively. Inversely, the decolorization efficiency (%) decreased from 98.0 to 29.0% with increasing initial dye concentration from 5 to 160 mg/L, respectively. The negative values obtained for Gibbs free energy (ΔG°) and positive value of enthalpy change (ΔH°) indicated spontaneous and endothermic nature of the process.     

HBPE-g-PVDF/PVDF blend nanofiltration membrane: preparation and characterization

Hyperbranched polyester-grafted poly(vinylidene fluoride) (HBPE-g-PVDF) was synthesized and used as additive in preparation of PVDF blend membranes. HBPE-g-PVDF copolymer was characterized with FTIR and TGA techniques. The prepared membranes were also characterized with SEM, AFM and contact angle measurement. The performance of prepared membranes as nanofiltration membrane was studied by pure water flux (PWF), salt rejection, dynamic and static fouling tests. The results showed that hydrophilicity of prepared membranes greatly increased after blending, and their pore size and pore size distribution and so PWF of blend membranes increased.     

Natural radioactivity measurements in the granite rock of quarry sites,Johor, Malaysia

This study was conducted to determine the concentration of natural radionuclides in the granite rocks of selected quarry sites in Johor state, Malaysia and their possible radiological effects. The activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K in the areas of study indicated varying values of ²³⁸U, ²³²Th and ⁴⁰K. The highest values of ²³⁸U and ²³²Th concentrations (67±1 and 85±2 Bq kg^?1, respectively) were observed at Kamad Quarry (IJM), whereas the highest value of ⁴⁰K concentration (722±18 Bq kg^?1) was detected in Kim Seng Quarry, while the values of activity concentration are lower in Hanson Quarry Products (Kulai) (25±0.5 for ²³⁸U, 24±0.5 for ²³²Th and 429±11 for ⁴⁰K). Overall, ⁴⁰K has the highest concentration in the granite rocks of the quarry sites, followed by ²³²Th and the least for ²³⁸U. The radium equivalent activity concentration was found in the range between 94 and 239 Bq kg^?1, the absorbed dose rate was found to be in the range between 47 and 112 nGy h^?1, and effective dose ranged from 58 to 137 μSv h^?1. Moreover, the internal and external hazard index values were given in results lower than unity.     

ASSOCIATION PHENOMENON OF A MIXED CATIONIC SURFACTANT IN NON-AQUEOUS SYSTEM

Pseudoternary phase diagrams of a mixture of two cationic surfactants, hexan-1-ol and a third component consisting of glycerol, formamide, water/glycerol or water/formamide were obtained. These diagrams were then contrasted with its water counterpart.

The results showed that the association phenomenon were entirely different from that of the corresponding water system. The lamellar liquid crystalline region was absent in both of the glycerol or formamide systems. This indicated a less ordered or destabilizing effect in the association structure resulting in the replacement water with that of glycerol or formamide. The presence of formamide resulted in a more destabilizing effect compared to the glycerol. This was shown by the smaller lamellar liquid crystal region obtained in the pseudoternary phase diagram containing equal weight ratio of water and formamide.