Academic Science Journal

In this study, the effects of temperature on the absorption and emission spectra of polyvinyl chloride films were investigated in the presence of diethyl phthalate as a quencher. In this paper, diethyl phthalate (DEP) was used as a quencher at different concentrations to study its effect on the behavior of absorption and emission spectra in the wavelength range from 200 to 350 nm. The films have been treated thermally at 25, 40, 50 and 60o C. The results showed that the absorption spectrum contains two absorption bands for all samples. The first absorption band appeared in the range of 200 to 220 nm. The maximum absorption band was shifted towards red wavelengths depending on the concentration and temperature.
The second absorption band appeared from 260 to 300 nm was weak, broad and unaffected by a concentration while showing a simple response to temperature without displacement in the maximum absorption (λmax.). The changes in absorbance as a function of quencher concentration at room temperature (25oC) are illustrated.
The spectra do not show sharp differences by changing the concentration of the quencher. The fluorescence emission spectra showed a strong peak at 372 nm. The effect of quencher on the quantum efficiency of the fluorescence emission using the Stern-Volmer equation was discussed.

(MoO3 / NiAl2O4) composite was prepared by ceramic method and calcined at (450 ̊C, 550 ̊C and 650 ̊C). The effects of the annealing temperature on the structural, magnetic and electrical properties of the samples were studied by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), vibrating sample magnetometry (VSM) and LCR-meter. XRD tests proved that the grain size values of phases are ranged between (55.34 and 58.68nm), as it is shown that a temperature of (550 ̊C) leads to the disappearance of (MoO3) phase and the emergence of new (NiMoO4) phase and this shows that the degree of heating increased the granular size. The results of the FESEM of (MoO3 / NiAl2O4) showed that the particle size values increased with the appearance of new phases. VSM tests proved that when increasing the amount of nickel and reduce the amount of alumina in nanocomposites, there is an increase in magnetic saturation (Ms) and this increase is irregular and leads to an increase in crystals size. The results of dielectric tests showed the emergence of the highest peak of the real and imaginary dielectric constant, at the lowest frequency which decreases with increasing frequency at low frequencies.

Forty isolates of Acinetobacter baumannii were obtained from 200 samples. The isolates were collected from different cases including: - wounds, burns, stool, urine, sputum and blood samples. For the period between 1/9/2016 to 30/11/2016. from several hospitals in Baghdad city (Central Children's Hospital, Al Karama Hospital, Karkh General Hospital, Al-Ameen Medical City Hospital, Educational Labs, Baghdad Teaching Hospital, Child Protection Hospital, Burns and Wounds Hospital). Genotypic detection for virulence genes (kpsM) of Acinetobacter baumannii, the result revealed that the kpsM gene was present in 6 isolates (15%) of A. baumannii possessed the kpsM gene. The resulting packets with a molecular weight were 272 bp. Sequential analysis detection of kpsM showed that nine silent mutations that did not effect of the amino acid translation. While two mutations effected in the translation of amino acids as there was a change in path of translation of the protein, where the conversion of the amino acid (Lysine) to the amino acid (Asparagine) and converted the amino acid (Isoleucine) to the amino acid (Valine).

In this work, we successfully prepared single wall carbon nanotubes (SWCNTs) / Epoxy polymer nanocomposites with different volume fraction ratios of SWCNTs (0, 0.2, 0.4, 0.6, 0.8, 1, and 1.5%) using mixing method in order to examine and study some of their mechanical properties (impact strength, hardness, creep). The Creep test result showed that the creep rate decreases gradually as the weight ratio of the SWCNTs reinforcement material increases in polymer. Impact strength and hardness values of samples were increased by increasing volume fraction of SWCNT reinforcement material in polymer compared with pure epoxy.

Dielectric materials used in electrical energy storage devices, must have a high dielectric constant with low dielectric losses. In this work, new method was used to improve the dielectric properties of 3Y-TZP (3% mol yttria tetragonal zirconia polycrystalline) ceramics, by adding different percentages of nano barium titanate (BaTiO3) to glaze mixture. 3Y-TZP specimens were sintered at a 1450 oC, and the glaze layer was fired at 800 °C. BaTiO3 increased from 40 wt% to 60% resulting an increase in the crystalline size. As well, both dislocation density and lattice strain were decreased down to 175×108 lines / mm2 and 12×10-3, respectively. The dielectric constant values were doubled up to 75.6 for glass-coated specimens when adding 60 wt% BaTiO3. This increase was accompanied by an increase in tangent losses value up to 0.026. Electrical breakdown Ebr of specimens was measured with the number of repeat breakdown and at different ramp rate of the voltage RRV. The Ebrmax is 55.7 kV / mm at RRV 5 kV / s for coated specimens without BaTiO3. A drop in Ebr has reached a minimum value of 41.7 kV/s at the same RRV. Various phenomena accompanied the Ebr, including electromechanical, electrothermal and electrical treeing.