Chemical Physics Review

Naturally occurring radionuclides of terrestrial origin (also called primordial radionuclides) are present in various degrees in all media in the environment, which includes the human body itself. Their concentrations in the environment decrease continually by decaying. In this study, the specific activities of different natural radionuclides were determined by using gamma-ray spectrometry. The analysis of two radionuclides (214Bi, 234m Pa) that belong to the 238U series and one radionuclide 228Ac belonging to the 232Th series, 40K, 226Ra, and 137Cs, was done for soil samples obtained from different locations in Iraq, which include factories, hospitals, and other facilities. The analysis of radionuclides measurement was done by using the high purity Germanium (HPGe) detector coupled with a computer-based high-resolution multichannel analyzer. The results showed that the average specific activities of 228Ac in sample 6, 214Bi, 234m Pa, and 226Ra in sample 2, 40K in sample 10, and 137Cs in sample 21 were higher than other samples. However, the activity concentrations of the analyzed radionuclides were very low in most samples.

The vibrational spectral analysis was carried out by using Raman and infrared spectroscopy in the range 4000–400 cm?1 and 4000–100 cm?1 respectively, for 2-amino-5-nitropyrimidine (2A5NP) molecule. The molecular structure, fundamental vibrational frequencies and intensity of the vibrational bands are interpreted with the aid of structure optimizations and normal coordinate force field calculations based on density functional theory (DFT) method and different basis sets combination. The complete vibrational assignments of wavenumbers were made on the basis of potential energy distribution (PED). The scaled B3LYP/6-311++G results show the best agreement with the experimental values over the other methods. The calculated HOMO and LUMO energies shows that charge transfer within the molecule. The results of the calculations were applied to simulate spectra of the title compound, which show excellent agreement with observed spectra. Electronic excitation energies, oscillator strength and nature of the respective excited states were calculated by the closed-shell singlet calculation method were also calculated for the molecule.

Complexes of monoethanolamine with Co, Ni, Zn and Cd are obtained according to the previously reported literature. Empirical formula assigned to the synthesized complexes from elemental analysis was found to be [Co(MEA)(H2O)2Cl2], [Ni(MEA)2Cl2], [Zn(MEA)(H2O)2Cl2] and [Cd(MEA)2SO4]. Thermogravimetry was done from ambient to 1000°C in order to check the thermal stability of complexes which was supported by FTIR spectra obtained at 150°C and 500°C. Initial decomposition temperature (Ti) values of complexes from Thermogravimetry showed the following order of thermal stability: [Cd(MEA)2SO4] > [Co(MEA)(H2O)2Cl2] > [Zn(MEA)(H2O)2Cl2] > [Ni(MEA)2Cl2].

TiO₂ Nanoparticles (TNPs) were prepared by sol-gel method using TiCl₄ as the precursor and propanol as the solvent. The sizes of TNPs were about 4 nm and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Visible spectroscopy (UV-vis). The X-ray powder diffraction studying explains that all the prepared samples have pure anatase phase tetragonal system. The gas sensing properties of TNPs were also investigated. We prepared porous poly silicon in nano and micron pores size by chemical electrolysation method and deposited TNPs by vacuum system (electron beam gun) with 23 nm thickness on porous poly silicon by sandwich method. I-V, and C-f curves was plotted. Gas sensing of this sandwich device increased in presence of TNPs in comparing with porous poly silicon without TNPs at room temperature by CO₂ gas.

The detection of benzene vapor composition formed inside the cars cabin has been investigated. Benzene is an organic chemical compound. The sample of benzene vapor composition is taken from a cars cabin and then the samples are analyzed by the gas chromatography-mass spectrometer (GCMS). The data is recorded and plotted by using the 4000 GCMS version 6’s software. Finally, the results show that there are different gases compositions inside the cars cabin. Beside of the gas (Z)-1-(Ethoxycarbonyl-1-Fluoro-2-(Methoxycarbonyl)-1, 3-Butadiene, that found inside the cars cabin, there are other gases as - (3-Oxo-3H-Benzo [F] Chromen-2-Yl)-2, 4(1H,3H) - Quinolinedione, Ethane-D6, Ethylene-D4, Heptacosafluoro-Tributylamine, Nonanal, Decanal, Tetradecanoic Acid, 11-Dodecen-1-Al, benzeneethanamine, 3-fluoro-a, 5-dihydroxy-N-methyl-, 2-Pyridinepropanoic Acid, a-Methyl-a-Oxo-Ethyl Ester, Silane Methyl-, Hexadecanoic Acid.

The present paper involves the synthesis of polyaniline (PANI) composite with cobaltmonoethanolamine [Co(mea)2(H2O)2Cl2] complex via in situ oxidative polymerization by ammonium persulphate. The complex has been synthesized by refluxing method. The composite has been subjected to elemental analysis, FTIR, and SEM characterization techniques. FTIR absorption peaks confirm the insertion of complex in the backbone of PANI. SEM of the composite also supports its successful synthesis.

Comparative study of stress intensity factor (SIF) for modes I, II and III were investigated for some engineering materials. The materials are alumina, iron, mild steel, low carbon steel, stainless steel, concrete, silica glass and PVC. Special crack-tip element method was implemented to evaluate the stress intensity factor (SIF) for centre, single-edge and double-edge crack for various values of shear modulus and symmetric crack-tip element size. Different SIF for various modes were compared for these materials and the results from the plots show that low carbon steel for mode III and alumina for mode II have high resistance to crack-growth at 12.43 and 12.2 SIF, respectively between the bounds of shear modulus 1.39 and 2.23. Also alumina for mode I exhibited crack growth at 1.42 SIF and 1.15 bounds of shear modulus. Mode I for mild steel, iron and stainless steel exhibited crack-growth at 0.691 SIF and 1.08 bounds of shear modulus. Mode I is anomalous to crack-tip element size while modes II and III show exponential decay but with crack growth in concrete and abscissa to the coordinate of PVC.

Indoor radon levels were measured in four seasons throughout 2013 in public hospitals for Iraqi Kurdistan, using a passive technique CR-39 nuclear track detectors. Thus, the highest and lowest values of rate indoor radon were in winter (105.3 ± 17.20 Bq/m3) and summer (39.92 ± 8.28 Bq/m3) season, respectively. This different value depended for ventilation rate, building material and geological formation. According to the estimation risk factor, the radon induced lung cancer risks for public hospitals in selected locations was varied from 2.7 ± 0.08 to 11.16 ± 1.94 per million people. The highest and lowest values of annual effective dose were recorded in winter and summer seasons, respectively.

Good quality single crystals of glycine sodium nitrate a new semiorganic nonlinear optical (NLO) crystal has been successfully grown from aqueous solution by slow evaporation method. The structural characterization of the grown crystals was carried out by X-ray diffraction. The grown crystals were subjected to FTIR for vibrational assignments. The optical properties were studied for the SHG efficiency. It is found that the cutoff wavelength lies in the UV region. The mechanical response of the crystal has been studied using Vickers microhardness technique.

The molecular vibrations of P-fluorobenzoyl chloride (PFBC) were investigated in polycrystalline sample, at room temperature, by Fourier transform infrared (FT-IR) and FT-Raman spectroscopies. In parallel, ab initio and various density functional (DFT) methods were used to determine the geometrical, energetic and vibrational characteristics of PFBC. On the basis of B3LYP/6-31G* and B3LYP/6-311+G** methods and basis set combinations, a normal mode analysis was performed to assign the various fundamental frequencies according to the total energy distribution (TED). Simulation of Infrared and Raman spectra, utilizing the results of these calculations led to excellent overall agreement with observed spectral patterns. The scaled quantum mechanical (SQM) approach applying selective scaling of the DFT force fields was shown to be superior to the scaling method in its ability to ensure correct band assignments and successful simulation of IR and Raman spectra including band polarizations and intensity patterns.