Gamma - irradiation effect on polymethylmethacrylate (PMMA) samples has been studied using Positron Annihilation Lifetime (PAL) method. The orthopositronium (o-Ps) lifetime τ3, hence the o-ps parameters, the volume hole size (Vh) and the free volume fraction (Ꞙh) in the irradiated samples were measured as a function of gamma-irradiation dose up to 28.05 kGy. It has been shown that τ 3, Vh, and Ꞙh, are increasing in general with increasing gamma-dose, to reach a maximum percentage increment of 22.42% in τ3, 60% in Vh and 29.5% in Ꞙh, at. 2.55 kGy, whereas τ2 reaches maximum increment of 119. 7% at 7.65 kGy. The results suggest that gamma-irradiation induces structure changes in PMAM, causing degradation in the main chains, and the presence of oxygen Causes reduction in the amorphous regions ; oxygen and the peroxy radicals form cross-linking at reactive sites between neighboring chains, giving a net reduction of the degradation yield.
The effect of different doses of gamma rays that emitted from 60Co on the development of different stages of lesser grain borer Rhyzopertha dominica (Fab.) was investigated . The results showed that the eggs in both early (1-3 days) and late (7-9) old were very sensitive to gamma rays and its hatch was zero at 10 Gy for both ages in comparison with 83.3% for the control group. Furthermore, the results illustrated that the larval stage in its two old ages were different in the radiosensitivity, the percent of its death were 100% & 96.6% when they exposed to 100 & 120 Gy, respectively. Moreover, the results showed that the sensitivity of pupal stage at age of 1-3 days was increased with increasing the doses of gamma rays, the percent of no
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Knowledge of permeability is critical for developing an effective reservoir description. Permeability data may be calculated from well tests, cores and logs. Normally, using well log data to derive estimates of permeability is the lowest cost method. This paper will focus on the evaluation of formation permeability in un-cored intervals for Abughirab field/Asmari reservoir in Iraq from core and well log data. Hydraulic flow unit (HFU) concept is strongly related to the flow zone indicator (FZI) which is a function of the reservoir quality index (RQI). Both measures are based on porosity and permeability of cores. It is assumed that samples with similar FZI values belong to the same HFU. A generated method is also used to calculate permea
... Show MoreThe Aim of this paper is to investigate numerically the simulation of ice melting in one and two dimension using the cell-centered finite volume method. The mathematical model is based on the heat conduction equation associated with a fixed grid, latent heat source approach. The fully implicit time scheme is selected to represent the time discretization. The ice conductivity is chosen
to be the value of the approximated conductivity at the interface between adjacent ice and water control volumes. The predicted temperature distribution, percentage melt fraction, interface location and its velocity is compared with those obtained from the exact analytical solution. A good agreement is obtained when comparing the numerical results of one
ten albino male rates were orally treated daily 20% and 30% ethanol for 30 days treatment with 30%ethanol caused of hippocampuse of darckness google hospital patients
This research aims to study the effect of heat on the efficiency of solar cells of neutrons ranging from card to these cells in the case of dark and light before and after irradiation using the neutron source as well as electrical properties have been studied
A dose of ten grams of the roots and leaves of Nettle (Urtica dioica) dissolved in (200)ml of boiled water then covered for (10)min. was given to a sample of (15) patients attending to the herbal department of ministry of health complaining of malnutrition and low Hb(hemoglobin) concentration and PCV(packed cell volume) levels with absence of any other predisposing factors disease inorder to find the effects of these roots and leaves on Hb and PCV levels for different periods of time in relation to age and sex variations . The study have shown that this mixture has a high significant effect (p<0.001) in elevating (Hb) concentration and PCV levels on those patients according to the differences recorded from the start of the basic period unt
... Show MoreThe semiconductor ZnO is one of II – VI compound group, it is prepare as thin films by using chemical spray pyrolysis technique; the films are deposited onto glass substrate at 450 °C by using aqueous zinc chloride as a spray solution of molar concentration 0.1 M/L. Sample of the prepared film is irradiating by Gamma ray using CS 137, other sample is annealed at 550°C. The structure of the irradiated and annealed films are analyzed with X-ray diffraction, the results show that the films are polycrystalline in nature with preferred (002) orientation. The general morphology of ZnO films are imaged by using the Atomic Force Microscope (AFM), it constructed from nanostructure with dimensions in order of 77 nm.
The optical properties o