A free convective heat transfer from the inside surface of a uniformly heated vertical circular tube has been experimentally investigated under a constant wall heat flux boundary condition for laminar air flow in the ranges of Ra_L from 6.910⁸ to 510⁹. The effect of the different sections (restrictions) lengths placed at the exit of the heated tube on the surface temperature distribution, the local and average heat transfer coefficients were examined. The experimental apparatus consists of aluminum circular tube with 900 mm length and 30 mm inside diameter (L/D=30). The exit sections (restrictions) were included circular tubes having the same inside diameter as the heated tube but with different lengths of

In this research, an experimental study was conducted to high light the impact of the exterior shape of a cylindrical body on the forced and free convection heat transfer coefficients when the body is hold in the entrance of an air duct. The impact of changing the body location within the air duct and the air speed are also demonstrated. The cylinders were manufactured with circular, triangular and square sections of copper for its high thermal conductivity with appropriate dimensions, while maintaining the surface area of all shapes to be the same. Each cylinder was heated to a certain temperature and put inside the duct at certain locations. The temperature of the cylinder was then monitored. The heat transfer coefficient were then cal

The current study aims to identify the feeling of job alienation and organizational commitment among free lecturers in secondary schools, as well as to identify the significance of the differences in the feeling of job alienation according to the gender and the significance of the differences in organizational commitment according to the gender. It also aims to identify the correlation between the feeling of job alienation and organizational commitment. To achieve the objectives of the research, the researcher developed two scales: one consisted of (24) items to measure the vacancy in job alienation and the other consisted of (24) items to measure the organizational commitment. The two tools were applied to a sample of (200) male and fem

The ability of four local fungal isolates for extracellular laccase production has been tested with five grams 1:1(w/v) humidified sawdust as substrate in mineral salt medium. After 21 day of incubation at 25±1 ? C and using one mycelial plug (5mm), higher level of laccase activity (0.15U/ml) and specific activity (15U/mg) were observed by Pleurotus ostreatus in comparison with other fungal isolates. The results of optimum conditions for laccase production from selected isolate showed that, the maximum laccase activity (0.55U/ml) and specific activity (55U/mg) were obtained at moisture ratio 1:3 (w/v), using 3 mycelial plugs (5 mm), after 15 days incubation period at 25±1 ? C. The results of phenol degradation by crud laccase revealed th

A new (Reversed Phase- High Performance Liquid chromatography) RP-HPLC method with Ultraviolet-Visible spectrophotometry has been optimized and validated for the simultaneous extraction and determination of antioxidants present in Iraqi calyces of Hibiscus Sabdraffia Linn. The method is based on using ultrasonic bath for extracting antioxidants. Limit of detection in μg/ml of Vitamin C, Sabdaretine, Gossypetine, Hibiscetine, Anthocyanins, Dephinidin-3-glucoside were113.8294×10-6,123.0453×10-6,70.3681×10-6,59.6730×10-6,148.1710×10-6,and125.3481×10-6 respectively. The concentration of antioxidants found in dry spacemen of calyces of Iraqi Hibiscus Sabdraffia Linn. under study: Vitamin C, Sabdaretine, Gossypetine, Hibiscetine, Anthoc

A batch and flow injection (FI) spectrophotometric methods are described for the determination of barbituric acid in aqueous and urine samples. The method is based on the oxidative coupling reaction of barbituric acid with 4-aminoantipyrine and potassium iodate to form purple water soluble stable product at λ 510 nm. Good linearity for both methods was obtained ranging from 2 to 60 μg mL−1, 5–100 μg mL−1 for batch and FI techniques, respectively. The limit of detection (signal/noise = 3) of 0.45 μg mL−1 for batch method and 0.48 μg mL−1 for FI analysis was obtained. The proposed methods were applied successfully for the determination of barbituric acid in tap water, river water, and urine samples with good recoveries of 99.92