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I. Valaei, S.R. Hassan-Beygi, M.H. Kianmehr and J. Massah

Abstract

The world’s dependence on chemical fertilizer as the primary source for enriching agricultural fields is continually increasing that cause nature pollution. This has led researchers to aggressively investigate renewable fertilizer resources, biomass, to produce organic crops and reduced wastage. Poultry litter is a bulk solid and biomass feed stocks. Flow behavior of bulk solid is a critical factor in designing and developing suitable equipments (e.g. pelletizing machine). The bulk density, tap density, Carr’s index and powder avalanche time technique were applied to evaluate the flow properties of poultry litter. The experiments were carried out at moisture content (10, 20 and 30% w.b.), particle size (0.3, 0.6 and 1.18 mm) for the bulk and tap densities as well as Carr’s index. In addition to the moisture content (10, 20 and 30 %w.b.) and particle size (0.3, 0.6 and 1.18 mm) the rotational speed of drum (0.5, 1 and1.5 rpm) were also investigated for the avalanche time. The results showed that with increasing moisture content Carr’s index increased significantly (P<0.01) in the ranges of 16.2% to 18.5% and with increasing particle size the Carr’s index decreased from 20.35% to 14.78%. The litter powder avalanche time (AT) increased significantly (P<0.01) with increasing moisture content and decreasing rotational speed and particle size. The bulk and tap densities of the litter powder was decreased with increasing moisture content and increasing the particle size. The bulk and tap densities of the driest and finest poultry litter sample were higher than other ones.

Open access

A.M. Abd-Elnaiem, M. Mohamed, R.M. Hassan, A.A. Abu-Sehly, M.A. Abdel-Rahim and M.M. Hafiz

Abstract

Chalcogenide glasses have attracted much attention largely due to their interesting physical and chemical properties. Though few published articles exist on the As-Te system, little is known about the optical properties of eutectic or near eutectic composition of As-Te system upon heat treatment. Therefore, this paper reports the effects of annealing temperature on the structural and optical parameters of As30Te70 thin films. The bulk and thin films of 150 nm thick As30Te70 chalcogenide glasses were prepared by melt-quenching and thermal evaporation techniques, respectively. The glass transition and crystallization reactions of the bulk samples were investigated using differential scanning calorimetry (DSC). The influence of annealing temperature on the transformation of the crystal structure was studied by X-ray diffraction (XRD), while the surface morphology of the annealed samples was examined using scanning electron microscope (SEM). The optical band gap, refractive index and extinction coefficient were also calculated. The DSC scans showed that the melting temperature remains constant at 636.56 K. In addition, other characteristic temperatures such as the glass transition temperature, the onset crystallization temperature, and the crystallization peak temperature increase with increasing the heating rate. The crystalline phases for the as-prepared and annealed films consist of orthorhombic As, hexagonal Te, and monoclinic As2Te3 phases. Furthermore, the average crystallite size, strain, and dislocation density depend on the annealing temperature. The optical absorption results revealed that the investigated films have a direct transition, and their optical energy gap decreases from 1.82 eV to 1.49 eV as the annealing temperature increases up to 433 K. However, the refractive index, extinction coefficient, dielectric constant and the ratio of free carrier concentration to its effective mass, increase with increasing the annealing temperature.

Open access

A.M. Abd-Elnaiem, M. Mohamed, R.M. Hassan, M.A. Abdel-Rahim, A.A. Abu-Sehly and M.M. Hafiz

Abstract

Effect of annealing temperature on the structural and optical properties of As30Te60Ga10 thin film was studied using various techniques such as differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The DSC analysis revealed that the As30Te60Ga10 glass has a single glass transition and crystallization peak while XRD results confirmed that the as-prepared and annealed films have crystalline nature. The coexistence of the crystalline phases in the investigated films could be attributed to the formation of orthorhombic As, hexagonal Ga7Te10, and monoclinic As2Te3 phases. It was found that the average crystallite size and optical parameters of the studied films depend on the annealing temperature. For example, the optical band gap decreased from 1.54 eV to 1.11 eV as the annealing temperature increased from 300 K to 433 K.

Open access

Nayera E Hassan, Sahar A El-Masry, Nadia L Soliman, Mona M El-Batran, Muhammad Al-Tohamy, Salwa R El-Batrawy and Mehrevan M Abd El-Moniem

Abstract

Background: Childhood obesity increases risk for developing cardio-metabolic diseases.

Objectives: to investigate the relation of some anthropometric parameters with cardio-metabolic disease risk factors in obese children and adolescents.

Subjects and Methods: Cross sectional study, comprised of 139 obese pupils; aged 8 to 16 years (classified to 3 age groups). Each pupil underwent complete physical examination, anthropometric and laboratory assessment (fasting blood sugar and lipid profile).

Results: Boys had significantly higher values of abdominal skin fold thickness in the age groups II and III and in central adiposity, waist circumference, waist/hip ratio and sub scapular skin fold thickness in adolescents. For boys, fasting blood sugar correlated with most of the anthropometric measurements in young age, and with skinfold thickness in the three age groups. While lipid profile correlated with skinfold thickness particularly at subscapular area in the age groups I and II. For girls, none of the parameters under study showed any significant correlation except subscapular skinfold thickness which had significant correlations with lipid profile in age groups I and II.

Conclusion: Skin fold thickness particularly subscapular; is important indicator for cardio-metabolic complications in obese children of both sexes. Obese boys are more liable to cardio-metabolic complications.