Journal of Kufa - physics

The best way to a chive good shielding of 14 MeV neutrons was investigated. The idea is to thermalize as many neutrons as with a given shielding thickness. Since hydrogenous material is not efficient for thermalization of 14 MeV neutrons, the neutrons are first slowed down with iron to energy rang where hydrogen is more efficient for thermalization. Layers of iron and polyethylene of various thicknesses that add up to 20 cm were investigated and it was found that a composition of 10 cm of iron before 10 cm of polyethylene gives the highest number of thermal neutrons. The fast neutron flux leading out of the shielding is decreasing continuously with increasing iron thickness.

The low lying levels structure and electric quadrupole transitions of 106-116Pd nuclei have been studied by using the Interacting Boson Model-1 (IBM-1). The Potential surfaces of these nuclei are also studied and the shapes of them are analyzed. The calculated results are in good agreement with recent experimental data. The results obtained and the values of parameters used in this calculations indicated that Pd isotopes have a vibrational properties with small amount of rotational and pair properties. tendency towered some more rotational properties appears as the number of neutrons approaches mid-shell between 50-82 shells.

The effects of the solar radiation pressure and the attraction of the sun and the moon at highEarth orbit satellite have been investigated . Computer simulation forthe equation of motion and velocity with perturbations is designed by Matlaba 7.4 where using Jacobian matrix method to increase theaccuracy

Electochromic material came to public attention around 30 years ago, nickel oxide(NiO) thin film(which is one of the inorganic electrochromic material) has grown on cleaned glass substrate at 498 oK temperature using spray pyrolysis deposition technique of thickness(1451.8A0).UV.-VIS. spectra of the film was studied by using the optical absorbance measurements which were taken in the spectral region from 300nm to 1100nm. The transmittance and reflectance spectra of the film in the UV.-VIS. region were also studied. Optical Constants such as optical allowed and forbidden energy band gap of direct transition, absorption coefficient, extinction coefficient, refractive index and optical conductivity, were evaluated from these spectra. The film was found to exhibit high transmittance(~55-87%) and high absorbance values at ultravioletregion which they decrease rapidly in the visible / near infrared region. Optical allowed band energy for direct transition was (3.694eV) and the forbidden one was(3.653eV).

In this research we studied theeffect of the atomic number on some atomic properties for systems have two electrons but different in atomic numberslike He-atom(Z=2) , H--ion (Z=1) and Li+-ion (Z=3) .We observed that the correlation energy increasing with increased atomic number , where the results are(-0.48793, -2.85316 and -7.23632) .Thecomparison with the experimental results we found good agreement .All propertiesstudiedin this research werechecked according to the normalization condition and we the atomic unit were used .

The aim of this research to use extracted natural material from waste product of Okra as blowing material by simple method for production sponge rubber.The sample of rubber was prepared with adding different percent from extracted material of waste product of okra (0-25) %to study the effect of this material on properties of natural rubber. When we added different percent from blowing material that extracted from plant of okra,It willformcells inside the sample due to degrade blowing material, release gases and get sponge rubber causes decrease maximum torque( from 17.55 to15.51)Ib.in, cure time(from 1,87 to1.41)min. This mean is extracted material of waste product of okra is suitable to use asblowing material to get sponge rubber and this work exists with a good replacement for synthetics blowing materials avoiding their toxicity and their highly cost.

Thermal cell calculation for PWR was carried out . Thermal cross sections , group constants and their coefficients (f,) for several cells with square and hexagonal geometry for different fuels (UO2, PUO2–UO2) and different enrichments had been calculated using Leopard and Thermos –OTA codes . NB-1 , NB-2 , NB-3 , NB-4 , NB-5 and LOFT cell were used as benchmarks , the absolute relative percentage error in the results did not exceed (1%) . One must mention that the results obtained by Thermos–OTA are more accurate by Leopard specially for LOFT cell .

We have been studied the effect of central elliptical obscuration inside elliptical aperture on the point spread function(PSF)to diffraction –limited system of different values of obscurative ratios (ε=0.25,0.5,0.75),where the results showed that the increase of obscurative ratio yield to decrease in (PSF).Elongation ratio also was studied for elliptical aperture and elliptical obscuration on (PSF)where the elongation increment for horizontal axis (major axis) leading to significant improving in (PSF).