Rafidain Journal of Science

This research aimed to find the rang of the electromagnetic reaction. It does that according to the theory of secondary photons, quantized time (T = 2nћ/E), and the photon rest mass (mo=hH/2c2), and by calculating the range of the photon at this time its found that it is(T=2c/H), and it is with full agreement with the result that found previously

Experimental studies have been made to determine the oxidation be havior of several coatings system on commercial stainless steel alloy (S.S. 321). The oxidation kinetics of a single stage coating such as Aluminized and Nickel - Aluminzed alloy have been under atmospheric studies pressure at 1000Co using a thermal cyclic oxidation. X-ray technique was used to identify the coating structure and oxide scale.
Most coating use to enhance the formation of protective oxid scale, the results showed that non of the coating was totally resistant to cyclic oxidation. But Nickel–Aluminized coating, exhibited the greatest resistance to oxidation . The superiority protection of Nickel – Aluminzed coating can be due to the formation of NiO and Al2O3.

Samples of MOS devices which were prepared by anodic oxidation method in which three electrodes used with HCl of 0.1 M. The thicknesses of SiO2 film were between 45& 80Ao . The effect of -ray on the characteristic of these devices studied through the measurements of I-V and C-V before and after irradiation. The results point to that the capacitance decreased after irradiation and an increase in the conductivity observed which indicates a decrease of potential barriers of these devices. The measurement of I-V for these samples as solar cell showed a decrease in the output power.

In this paper, the energy response of the solid state nuclear track detector PM-355 for -particles within the energy range of  5.5MeV have been studied using an 241Am(1ci) source in irradiating the detectors pieces. It has been found that the threshold energy, which defined as the minimum energy that could be detected, is about 0.3 MeV for PM-355. While the track detector CR-39 responses to the -energy approximately up to 0.2 MeV, when a conventional chemical etching is used. The results also indicates that the etching efficiency and sensitivity of the CR-39 is better than that of PM-355. They showed a maximum values when the incident energy of the -particle is about 1.5MeV, where a maximum energy loss in the detector is taking place.

Two different types of aluminide coatings on cyclic austenitic stainless steel 321 AISI, were investigated. One is based on predeposition of nickel by electrodeposition followed by aluminization using a pack cementation technique (double step- coating), while the other coating is based on codeposition of nickel and aluminium powder simultansly using a pack cementation (single step- coating).
The coating microstructure and intermetallic compound of the coating layers, as well as, coating thickness were identified using metallugraphy and X-ray analysis
The cyclic Oxidation test of the coating at elevated temperature reveals the formation of stable and protective scale -Al2O3 along the exposure time.

The aim of this research to study the effect of etching conditions such as the concentration of the etchant solution, and temperature on the detecting properties of nuclear track detector (cellulose nitrate) CN-85, in order to determine the optimum etching conditions. An (NaOH) solution with (3, 4, 5, 6N) concentrations and temperatures range (40,50,60o C) has been used for the following etching times (0.5-4 hr) to develop tracks of alpha particles with energy 1.5MeV of emanated from 241Am source of (1µCi) activity. It is found that an increment in the concentration and the temperature of the solution leads to an increment in the diameter of the tracks, it was also noted that an increment in the temperature by 10Co leads to an increment in the average radii of tracks by (75 – 210 %) .Eventually it is found that for each specific temperature of etchant optimum condition of specified etching time, (which appears the highest number of tracks) and also specified the track diameter, these two condition will be changed when the concentration of etchant is also change at a fixed temperature.

The increase in the production of solid materials requires a simple and easy method to measure the density of these materials. A method is suggested to measure the density which is based on the absorption of gamma ray at certain energy which helps to measure the density with error less than 4.6% and in case the error exceeds the previous percentage the absorption material may contain impurities.

The study aim determine the energy response of nuclear track detector cellulose nitrate CN-85 with thickness (100µm) for alpha particles emanated from Americium source 241Am of (1µCi) at irradiation time (5 min). The process of the irradiated detectors has been done by using the etchant (NaOH) with normality (5N) and etching temperature (50°C) for different times(0.5-4.5hr). The results led to determine the energy spectrum of alpha particles which the detector responded to with energy range (0.2-4.5 MeV). It has also been found that there was an increment in average of radii tracks with Etching time for all the used energies , it has also been observed that track density change with etching time for the above energies. In addition , we reached at determining the optimum etching times to reveal all formed tracks and also all the used energies and the maximum absorption energy occurs at 1.5 MeV.

In this research ,a new pack design has been used for production of metallic coating for alloys, in order to resist oxidation and corrosion at high temperatures. Such alloys are manufactured for some parts of Gas Turbine engines and boilers.
In traditional pack cementation method for production of aluminide coating, a mixture of powders, such as, Aluminium ,Ammonium chloride ,and Alumina were mixed together at a certain percentage, and the parts to be coated are submerged in this mixture, after coating time proceeds, the mixture is usually discarded and can not be used again because the Ammonium chloride which has been dissociated can not be replaced with the same percentage again.
This process could lead to a high loss of unused Aluminium powder.
This new pack design can offers an opportunity to isolate Ammonium chloride (activator) from the rest of pack mixture, by so, one can substitute the activator alone without replacing the rest of mixture.
Such pack design has been used in the investigation of coating production at different temperatures and the structure of the coating produced was compared with that produced in traditional method for the same alloy , and the results were indicated to a good similarity of structure except in thickness.

In this work, Metal-Polymer-semiconductor devices (MPS-Devices) have been fabricated using a thin film of Poly carbonate (PC). From characterization of the devices, threshold voltage (VT) and breakdown voltage (VB) were determined.The effect of Polymer films thickness and the temperature on the (VT) and (VB) were studied.The
results show that both voltages increase with increasing Polymer film thickness and decrease with the temperature. Illuminated (I-V) characteristics of the fabricated device were studied also, it was clear that the current and voltage increases with increasing illuminated intensity, while (VT) decrease with increasing illumination intensity. Finally the (C-V) characteristics was studied, the results showed that there are change in the capacity with change a voltage within range, out of this range the capacity fixed and the capacity of the device increases with increasing the frequency at same value of voltage.

In the present work, the effect of annealing temperature, annealing time and etching time on the track diameter of -particle have been studied using CR-39 Detector.
Two models were used to measure the activation energy (Ea) at each time periods.

Rubber is produced by volcanization which is achieved by different ways one of theses is by compression in molds by which samples under research were produced in jabir bin hayyan com. In this research the effect of compression temperature on the homogeneity of rubber kind (MCG) which is used in protection masks was studied. After the best degree of temperature was investigated to be (175 oC) then the effect of compression pressure on the characteristics of the rubber for two types of samples prepared by this way, by studying their homogeneity and mechanical properties. This study fixed the best pressure at (150 bar). The practical benefit for this study is to decrease the damage of the product and get best product with best mechanical properties and homogeneity.