Heat transfer process and fluid flow in a solar chimney used for natural ventilation are investigated numerically in the present work. Solar chimney was tested by selecting different positions of absorber namely: at the back side, front side, and at the middle of the air gap. CFD analysis based on finite volume method is used to predict the thermal performance, and air flow in two dimensional solar chimney under unsteady state condition, to identify the effect of different parameters such as solar radiation. Results show that a solar chimney with absorber at the middle of the air gap gives better ventilation performance. A comparison between the numerical and previous experimental results shows fair agreement.
This study is a numerical investigation of the performance of reinforced concrete (RC) columns after fire exposure. This study aims to investigate the effect of introducing lateral ties and using the RC jacket on improving post-fire behavior of these columns, the effect of the duration of the fire on ultimate load of columns. The analysis was performed through ABAQUS, a 3D – non-linear finite element program. 4 m tall lengthening square RC column with a cross- section of 0.4 m × 0.4 m was used as a test specimen. The RC column was reinforced by 4Ø28 mm longitudinal bars bonded by steel tie bars of Ø10 mm spaced at 400 mm. The firing temperature was increased to 60
Strengthening of composite beams is highly needed to upgrade the capacities of existing beams. The strengthening methods can be classified as active or passive techniques. Therefore, the main purpose of this study is to provide detailed FE simulations for strengthened and unstrengthened steel–concrete composite beams at the sagging and hogging moment regions with and without profiled steel sheeting. The developed models were verified against experimental results from the literature. The verified models were used to present comparisons between the effect of using external post-tensioning and CFRP laminates as strengthening techniques. Applying external post-tensioning at the sagging moment regions is more effective because of the e
... Show Moreinsulin-like Growth Factor 1 (IGF-1) gene has been described in several studies as a candidate gene for growth. The present study attempts to identify associations between body weight traits and polymorphisms at 279 position of 5'UTR flanking region of IGF-1 gene in broiler chickens. Three hundred broiler chickens from two breeds (Cobb 500 and Hubbard F-15) were used in this study. A single nucleotide polymorphism (SNP) at 279 position of 5'UTR region of the IGF-1 gene was identified in 20.6 and 60.3% of Cobb 500 and Hubbard F-15, respectively, using the PCR-RFLP technique. Allele frequencies were 83.87 and 42.80% for the T allele and 16.13 and 57.20% for the C allele in Cobb500 and Hubbard-15 breeds, respectively. Genotype frequencies were
... Show MoreThe objective of the study: is to investigate the correlations between the HER2 neu gene status with the clinicopathological parameters of infiltrative breast carcinoma. A total of seventy four Iraqi breast cancer patients were collected from one center (Department of Public Health) paraffin blocks were collected from histopathology department central public health laboratories, Bagdad, Iraq from 2014-2015. The cases which has been taken included invasive ductal and invasive lobular carcinoma type Women age were ranged from 24-80 years old. Evaluation of Her-2/neu gene amplification status was done using FISH and CISH techniques that showed a significant correlations with clinicopathological parameters.
By using vacuum evaporation, thin films of the (CdS)0.75-(PbS)0.25 alloy have been deposited to form a nanocrystalline composite. Investigations were made into the morphology, electrical, optical and I-V characteristics of (CdS)0.75-(PbS)0.25 films asdeposited and after annealing at various temperatures. According to AFM measurements, the values of grain sizes rise as annealing temperatures rise, showing that the films' crystallinity has been increased through heat treatment. In addition, heat treatment results in an increase in surface roughness values, suggesting rougher films that could be employed in more applications. The prepared films have direct energy band gaps, and these band gaps increase with the increase in the degrees
... Show MoreThis study examines the monthly mean diurnal variations of the ionospheric sporadic E (Es) layer’s critical frequency (
Decolorization of red azo dye (Cibacron Red FN-R) from synthetic wastewater has been investigated as a function of solar advanced oxidation process. The photocatalytic activity using ZnO as a photocatalysis has been estimated. Different parameters affected the removal efficiency, including pH of the solution, initial dye concentration and H2O2 concentration were evaluated to find out the optimum value of these parameters. The results proved that the optimal pH value was 8 and the most efficient H2O2 concentration was 100mg/L. Toxicity reduction percent for effluent solution was also monitored to assess the degradation process. This treatment method was able to strongly reduce the color and toxicity of reactive red dye-238 to about (99 an
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