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.
Electro-chemical Machining is significant process to remove metal with using anodic dissolution. Electro-chemical machining use to removed metal workpiece from (7025) aluminum alloy using Potassium chloride (KCl) solution .The tool used was made from copper. In this present the optimize processes input parameter use are( current, gap and electrolyte concentration) and surface roughness (Ra) as output .The experiments on electro-chemical machining with use current (30, 50, 70)A, gap (1.00, 1.25, 1.50) mm and electrolyte concentration (100, 200, 300) (g/L). The method (ANOVA) was used to limited the large influence factors affected on surface roughness and found the current was the large influence f
... Show MoreA condense study was done to compare between the ordinary estimators. In particular the maximum likelihood estimator and the robust estimator, to estimate the parameters of the mixed model of order one, namely ARMA(1,1) model.
Simulation study was done for a varieties the model. using: small, moderate and large sample sizes, were some new results were obtained. MAPE was used as a statistical criterion for comparison.
The extraction of Cupressus sempervirens L. or cypress essential oil was studied in this paper. This cypress oil was extracted by using the hydro-distillation method, using a clevenger apparatus. Cupressus sempervirens L. leaves were collected from Hit city in Al-Anbar province – Iraq. The influences of three important parameters on the process of oil extraction; water which used as a solvent to the solid ratio (5:1 and 14:1 (ml solvent/g plant), temperature (30 to 100 °C) and processing time, were examined to obtain the best processing conditions to achieve the maximum yield of the essential oil. Also, the mathematical model was described to calculate the mass transfer coefficient. Therefore, the best conditions, that were obtained in
... Show MoreThe research started from the basic objective of tracking the reality of organizational excellence in educational organizations on the basis of practical application. The research in its methodology was based on the examination of organizational excellence in the way of evaluating institutional performance. Tikrit University was selected as a case study to study the reality of application to the dimensions of organizational excellence in it, The results of the analysis for ten periods during the year and month. For the accuracy of the test and its averages, it was preferable to use the T test to determine the significance of the results compared to the basic criteria.
The research found that there is an o
... Show MoreIn the present investigation two different types of fiber reinforced polymer composites were prepared by hand lay-up method using three different parameters (curing temperature, pressing load and fiber volume fraction). These composites were prepared from the polyester resin as the matrix material reinforced with glass fibers as first group of samples and mat Kevlar fibers as the second group, both with different volume fractions (4%, 8%, and 12%) of fibers. They were then tested by tensile strength and impact strength. The main objective in this study is to use Taguchi method for predicting the better parameters that give the better tensile and impact strength to the composites, and then preparing composites at
... Show MoreBackground: Large amounts of oily wastewater and its derivatives are discharged annually from several industries to the environment. Objective: The present study aims to investigate the ability to remove oil content and turbidity from real oily wastewater discharged from the wet oil's unit (West Qurna 1-Crude Oil Location/ Basra-Iraq) by using an innovated electrocoagulation reactor containing concentric aluminum tubes in a monopolar mode. Methods: The influences of the operational variables (current density (1.77-7.07 mA/cm2) and electrolysis time (10-40 min)) were studied using response surface methodology (RSM) and Minitab-17 statistical program. The agitation speed was taken as 200 rpm. Energy and electrodes consumption had been studi
... Show MoreObjective Tea lovers are increasing worldwide. We hope that this report is the first to discuss the possible impacts of high black tea consumption on gestational weight gain (GWG) and birth parameters. Methods Throughout one year, a total of 7,063 pregnant ladies coming for first antenatal visit were screened in a major tertiary center. Of them, 1,138 were involved and divided according to their preference into 3 groups: excessive tea (ET), usual tea (UT), and mixed beverages group. The study included women who gave birth to healthy neonates. Results The rate of ET consumption was 4.13% with a total of 41 cases. The UT group (controls) comprised 94 women. ET was significantly associated (P<0.05) with maternal age, parity, occupation, smokin
... Show MoreEriobotrya japonica Lindl., named as loquat, is a subtropical fruit tree of the family Rosaceae which is well known medical plant originated in Japan and China. Loquat portions, like leaves, peels and fruits have been shown to possess various health usefulnesses. In Chinese classical medicine, it is vastly utilized in many illnesses, like gastroenteric disorders, diabetes mellitus, pulmonary inflammatory diseases and chronic bronchitis. Loquat plant contain many active constituents, such as flavonoids, carotenoids, vitamins, polyphenolic compounds, other that have many biological effects like anti-tumor, anti-diabetic, anti-inflammatory, anti-mutagenic, antioxidant, antiviral, antitussive, hepatoprotective and hypoli
... Show MoreAnatomical changes in internal tissue of stem and leaf when seed and plant treated with acids to enhance growth and development in maize was studied during the spring seasons of 2019 and 2020. Randomized complete block design was used with three replications. Main plots received foliar nutrition treatments, including ascorbic acid (AA), citric acid (CA), and humic acid (HA) at concentrations of 100 mg L−1, alongside HA at 1 ml L−1, with distilled water as the control. Sub-plots underwent corresponding treatments for seed soaking. Results indicated variations in vascular bundle size among treatments, with foliar CA treatment showing superior results in both years, as well as seed soaking in CA and HA. Interaction effects were observed, n
... Show More