Chemical Physics Review

Cadmium Sulphide (CdS) thin films of different thickness are prepared by the chemical bath deposition technique on well cleaned glass substrates at various temperatures. The thicknesses of the deposited films have been determined by gravimetry. The structural characterization is carried out by X-ray diffraction. The study confirms the polycrystalline nature of films with hexagonal structure. The structural parameters such as grain size, dislocation density, strain and lattice parameters have been evaluated. The composition of various constituents in CdS films have been determined by energy dispersive X-ray analysis. The optical properties like optical transmittance, band gap and refractive index has been studied in detail for the CdS films of various thicknesses which would be a promising material for the photo-voltaic applications. This paper deals with structural and optical properties of chemically deposited CdS films at the temperatures 600 C and 700 C  with the composition of CdCl2 in aqueous solution 0.2 gm and 0.3 gm.

This paper presents the effect of five dissolved inorganic salts (NaCl, CaCl2, ZnCl2, CdCl2 and NH4Cl) on the endothermic enthalpy of mixing of the binary methanol + ethyl acetate system has been investigated at 303.15 K, using an isothermal batch calorimeter with vapour space. The endothermic excess enthalpies of mixing values are significantly increases for the addition of ZnCl2, CdCl2 and CaCl2. For the addition of NaCl and NH4Cl salts are insignificantly decreases the endothermic excess enthalpy values. The experimental values of the enthalpy of mixing were fitted into a Redlich – Kister equation, the deviations and parameters were reported. The experimental and correlation results reveals that the importance of the solvent- solvent and solute-solvent interaction by the enhanced excess enthalpy of mixing (HE) values in the positive direction with increasing concentration of the salts.

Exposure to natural sources of radiation, especially 222Rn and its short-lived daughter products has become an important issue throughout the world because sustained exposure of humans to indoor radon may cause lung cancer. Therefore, indoor radon concentration levels have been measured inside 8 government hospitals in three main regions (Erbil, Duhok and Sulaymaniya) in Iraqi Kurdistan region during summer season by using CR-39 nuclear track detector. The CR-39 detectors were placed in the all hospitals for three floors (ground, first and second). The highest average radon concentration value and annual effective dose was found to be in the Shaheed Dr.Aso hospital in Sulaymaniya city (52.89±3.52 Bq.m-3 , 1.37±0.09 mSv/y ) respectively and the lowest was found in the Erbil Teaching hospital in Erbil city (30.15±2.85 Bq.m-3 , 0.81 mSv/y) respectively, This depended on the geological formation , type of building material, and the floor level. Therefore, the results showed that the average radon concentration and annual effective dose decreases gradually as the floor level increases The highest and lowest of annual effective dose was found in ground and second floor, respectively. Thus, according to the annual exposure dose data, the workers are safety in most of the hospitals.

Polyaniline/ poly(o-toluidine) /MMT-clay nanocomposites can be prepared by mechano chemical method in which, interaction of precursor anilinium ion into the clay lattices accomplished by mechanical grinding of Na-MMT in presence of anilinium hydrochloride at room temperature using mortar and a pestle for about 30 minutes and subsequent grinding with oxidizing agent, ammoniumperoxysulphate. The appearance of green colour indicates the formation of polyaniline/ poly (o-toluidine)/ MMT-clay nanocomposites. The morphology and structural characteristics of the polyaniline clay nanocomposites were investigated using FTIR, XRD, Cyclic voltammogram and SEM.

For all structural/functional application, tribological properties of material play most prominent role in day to day life. Tribology arises when there is relative motion between two surfaces in contact results loss of mass from surface by rubbing. To restrict this type of wear suitable lubricant can be use. This paper describes about wear behavior of three composites specimen made from constituting elements: alumina oxide, titanium dioxide and copper with the help of pin on disc machine. These three specimen pellets are made by powder metallurgy technique by increasing the furnace temperature from 1000C to 7000C with a rate of 30C/min. From wear test, wear rate graphs are plotted with respect to sliding velocity. In this study it is found that, composition of composites and sliding velocity majorly impart on wear rate. Our present aim is to test the mixture of various compositions of alumina and titanium in a copper base and test it for its different properties, to compare it with pure alumina. Among three composite it is observed that more the amount of TiO2 percentage, lesser is the wear rate. This investigation can help to improve the tribological properties of surfaces by varying their composition.

Iron-clay based composite resistor of varying iron content and aspect ratio have been fabricated using a pressure of about (2.04x108) Nm-2 for all the resistor moulded, expect in the case where the pressure was varied with four different pressures of about 1.28x108Nm-2, 0.66x108Nm-2, 2.04x108 NM-2 and 2.41x108Nm-2 with composition of 70% iron, length of 15mm and particle size of 0-25µm. The effect of clay particle size was also investigated using particle size ranging from 0-250µm, 250-400µm, 400-500µm and 500-850µm. Iron powder was used as the conductive element while the clay powder served as insulating and binding element. The fabricated resistor all have an average diameter of 3mm; for those moulded with particle size of 0-25irm, the length are varied between 5mm and 25mm increasing in 5mm and composition of 95%, 90%, 85%, 80% and 75% iron content. The resistors were investigated for influence of composition, firing time, firing temperature, length particle size and moulding pressure on their electrical properties. The results show that the electrical resistance increases with increasing resistors length and increasing the diameter of the clay particle size. However, the electrical resistance falls rapidly with increasing firing temperature, firing time, moulding pressure and also with increasing functional composition (iron composition). The modeled results also shows that polynomial of the 2nd order best describes the results obtained.

Graphene zinc oxide composites have been successfully synthesized via a hydrothermal reaction using graphite zinc chloride as starting materials. These prepared composites with different ratios of graphene and zinc oxides were characterized by X-ray diffraction (XRD), Raman and solid UV-Vis spectroscopies, and thermogravimetric analysis (TGA). The TGA analysis reveals that the intercalation of ZnO into graphene layer expands the d – spacing between graphene sheets and reduces the oxidation temperature. The results from XRD, Raman spectroscopy show that composites possess both characteristics of graphene and ZnO, and there is existence of interaction between ZnO and oxygenated functionalities on graphene sheets. In the photocatalytic reaction, the composite containing 10% in mass of ZnO exhibits the highest photocatalytic efficiency of 97.13% after 13 hours exposing to sun light

This paper involves the synthesis of photoadduct of Potassium hexacyanoferrate and phenanthroline via photochemical route .The photoadduct has been synthesized by photoirradiation followed by substitution with phenanthroline ligand. The photoaquation, substitution and successful synthesis has been proved by recording pH, colour change, UV visible spectra before and after irradiation. The as synthesized photoadduct has been subjected to various spectroscopic and surface characterization techniques like elemental analysis, UV-visible spectra, XRD, and SEM. XRD of photoadduct shows crystalline structure. Moreover parameters like crystallite size (L), interplanar distance (d), micro strain (?), dislocation density (?) and distortion parameters (g) were evaluated from XRD data using Schrerrer and other equations for the photoadduct.

The experimental and theoretical study on the structure and vibrations of 1,2,4-triazine-3,5(2H,4H)-dione have been carried out by ab initio HF and DFT/B3LYP method with 6-311++G(d,p) basis set. The FT-IR and FT-Raman spectra of the title compound have been recorded. The molecular structure, vibrational wavenumbers, infrared intensities and Raman activities were calculated. The force constants obtained from this study have been utilized in the normal coordinate analysis. The temperature dependence of thermodynamic properties has been analyzed. Molecular electrostatic surface potential (MESP), total electron density distribution and frontier molecular orbital’s (FMO) are constructed at B3LYP/6-311++G(d,p) level to understand the electronic properties. The atomic charges, electronic exchange interaction and charge delocalization of the molecule have been performed by natural bond orbital (NBO) analysis.

Propagation of large amplitude ion acoustic solitons are investigated in four component plasmas, whose constituents are inertial ions, nonthermal electrons, Boltzmannian positrons and dust particulates. The solitary waves as well as its properties are investigated through pseudopotential approach. It is observed that the presence of dust particulates considerably modify the potentials as well as width of the solitary wave.