Kirkuk University Journal-Scientific Studies

To enhancement the superconductor structural characteristics, nanoparticles of the Al₂O₃ were added to the samples under study. The Samples of high temperature superconductors 1-X (Bi₂Ba₂Ca₂Cu₃O₁₀₊ ) + X(Al₂O₃) with X= (0-0.9) were prepared by solid state reaction method under hydraulic pressure 8 ton/cm² and annealing temperature 800 . Electrical properties of the samples showed that T_c increases from 126 K to 139 K, and also oxygen content in samples increased with increasing X values from 0 to 0.5, while T_c decreased less than 77 K with increasing X at values more than 0.5. In Structural properties, the X-ray diffraction of the samples showed orthorhombic phase with a=4.286A , b=5.4184A , c=35.3528A  at X=0, while c-value is increased to 35.9848A  at X=0.5. AFM results shows that the average grain size of the best sample was 47.67 nm at X=0.5. SEM it showed that there are dark regions related to the heavier elements, such as Bi and Cu, and light regions related to lighter elements, such as Ba and Ca, depending on atomic weights

Hydrogen is considered one of the most promising source of clean and renewable energy as an alternative for environment polluting fossil fuel resources. The safe and reasonable volumetric density storage represent the main problem facing the hydrogen technology. Most of the research nowadays are focusing on development of new technologies for solid state storage of hydrogen. At the present study, The adsorption of hydrogen molecule (H₂) has been studied on the supercell (3 x 3 x 1) of pure graphene and doped graphene  with boron atom and adsorbed with lithium atom by first principle calculations with DFT method. We choice local density approximation (LDA) To describe the exchange-correlation energy between the interacting electrons and the basis set (Double Numerical Plus polarization DNP), the regions of a Brillion zone are set to (2 x 2 x 1). The binding energy of hydrogen molecules adsorbed on the surface of graphene adsorbed by the lithium atom was between (0.2-0.4 eV) and with a storage ratio (6.74 wt.%), Which meets the gravitational capacity standard specified by the energy department, And the binding energy of hydrogen molecules adsorbed on the surface of graphene adsorbed by the lithium atom and doped with the boron atom was between (0.23-0.32 eV) and with a storage ratio (6.67 wt.%), Thus meeting the standard for the final mass capacity (6.5 wt.%) Specified by the Department of Energy.  We conclude that the doping of the boron atom into one of the six graphene rings in the large unit cell (3 × 3 × 1) played a major role in increasing the stability of the graphene surface and reduce the binding energy that contributes to reducing the temperature of the hydrogen desorption process.

Flame thermal spraying technology was used in the production of 25% zirconia composite material with 25% alumina particle with binder material of 50% Al-Ni alloy base on 316L alloy steel base, after preparation the base surface with a method of roughing the granular. Spraying was carried out using a spray distance (12,14,16,18,20) cm. Hardness tests were carried out on the composite material to study the effect of changing spray distance on the properties of the resulting layer. The thermal treatment was performed on the samples at (850,950,1050,1150)  for an hour. The results of the tests confirmed that the best spraying distance (16 cm) and the thermal treatment (1050 ) have a significant effect on improving the hardness of the layers of the composite material.

This study included the synthesis of O-carboxymethyl chitosan which contains amine group attached directly to its glucose unit from the well-known natural polymer (chitosan), which in turn was reacted with some aromatic aldehydes containing o- and p- substituents to prepare a series of Schiff bases compounds. The used aldehydes were; p-boromobenzaldehyde, o-hydroxybenzaldehyde, o-bromobenzaldehyde, p-chlorobenzaldehyde, and p-nitrobenzaldehyde. The synthesized compounds were characterized using spectroscopic techniques including FT-IR and ¹H-NMR. The thermal stability of some of the prepared compounds was checked using differential thermaogravimetric analysis DTA. Finally, the biological activity of two Schiff bases was measured against two types of bacteria (Escherichia coli) and (Staphylococcus aureus) in terms of inhibition rate.

In this research, the months of comfort and discomfort were identified using the Temperature-Humidity Index in selected stations in Iraq (Mosul, Baghdad, Basra) using data of the temperature and relative humidity values of the period (1983-2019) obtained from the Iraqi Meteorological organization and Seismology. The results showed that the months of discomfort in the three study stations were (January, July, August, December), while the months of comfort in the three study stations were both (April, September), while the months (February, March, June, September, November) alternated between comfort and discomfort in the three study stations. This research also clarified the effect of both temperature and relative humidity on the values of the Temperature-Humidity Index by clarifying the nature of the relationship between them by calculating the coefficient of correlation using Microsoft Excel (2010), where the results showed a linear strong correlation between temperature and Temperature-Humidity Index values, where the values ​​of correlation coefficients ranged between (0.996) – (0.997), while the correlation was inversely strong between relative humidity and Temperature-Humidity Index values where the values ​​of correlation coefficients ranged between (-0.985) – (-0.959) in the study stations, this indicates that the increase in the value of temperature and decrease relative humidity leads to an increase in the values of the Temperature-Humidity Index, and vice versa.

Pure Zinc oxide and ZnO/SeO₂ oxide thin films were prepared successfully by sol gel method and annealed at different temperature under ambient condition. These films were characterized by means of XRD, AFM, and UV-visible. XRD patterns clearly showed the presence of crystalline ZnO/SeO₂ particles, the ZnO/SeO₂ film showed a good crystallinity like pure ZnO film, Optical transmittance spectra of films showed high transparency (>87%) in visible region. The color coordinate and tristimulus value of transmittance spectral showed that the best decolourization result was achieved at 7.5 at.% Se at 400^oC, 600^oC and 10 at.% Se at 500^oC , for the best brightness result appeared at two point with 2.5 at.% Se at 600^oC and 7.5 at.% Se at 400^oC. AFM studies reveal that rms roughness of the thin films increased with the increasing of Se concentrations. Also, the surface roughness increased with the increasing of the annealed temperature.