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  • Author: Mohamed M. Hassan x
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Open access

Amr Mohamed Elazhary and Hassan M. Soliman

Abstract

An experimental study was conducted in order to investigate two-phase flow regimes and fully developed pressure drop in a mini-size, horizontal rectangular channel. The test section was machined in the form of an impacting tee junction in an acrylic block (in order to facilitate visualization) with a rectangular cross-section of 1.87-mm height on 20-mm width on the inlet and outlet sides. Pressure drop measurement and flow regime identification were performed on all three sides of the junction. Air-water mixtures at 200 kPa (abs) and room temperature were used as the test fluids. Four flow regimes were identified visually: bubbly, plug, churn, and annular over the ranges of gas and liquid superficial velocities of 0.04 ≤ JG ≤ 10 m/s and 0.02 ≤ JL ≤ 0.7 m/s, respectively, and a flow regime map was developed. Accuracy of the pressure-measurement technique was validated with single-phase, laminar and turbulent, fully developed data. Two-phase experiments were conducted for eight different inlet conditions and various mass splits at the junction. Comparisons were conducted between the present data and former correlations for the fully developed two-phase pressure drop in rectangular channels with similar sizes. Wide deviations were found among these correlations, and the correlations that agreed best with the present data were identified.

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

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

Nayera E. Hassan, Sahar A. El-Masry, Salwa M. Elshebini, Muhamed Al-Tohamy, Nihad H. Ahmed, Enas Abdel Rasheed, Gamila S.M. El-Saeed, Nagwa M. Hassan, Emad N. Zikri and Mohamed S. El Hussieny

Abstract

AIM: The aim of this study was to compare efficiency of three types of obesity management protocols: dietary measures and physical activity; acupuncture or laser acupuncture with healthy diet among obese females.

SUBJECTS AND METHODS: Randomized longitudinal prospective study, carried out on 76 adult females. Blood pressure, anthropometric, ultrasonographic and biochemical assessments were done.

RESULTS: Females undergo nutritional intervention showed highly significant improvement in the anthropometric measurements, visceral fat at umbilicus by US and diastolic blood pressure (decreased), and insignificant differences in fasting blood sugar and lipid profile. Female undergo acupuncture intervention showed highly significant improvement in visceral fat by US, lipid profile (decreased triglycerides, total cholesterol and LDL, and increased HDL), and decreased fasting blood sugar, and insignificant differences in the anthropometric measurements. Those undergo laser intervention showed highly significant improvement in all anthropometric measurements under study, visceral fat at umbilicus by US, blood pressure and some parameters of lipid profile (decreased total cholesterol and LDL).

CONCLUSIONS: Nutritional intervention alone could be used to reduce weight if the lipid profile within normal range, but if it is impaired, acupuncture should be used beside. To strength the reduction in body anthropometry, laser intervention was recommended beside the nutritional intervention.

Open access

Ali K. Alzahrani, Mostafa M. Farag, Said H. Abbadi, Mohamed M. Hassan, Ahmed Gaber and Ahmed S. Abdel-Moneim

Abstract

Background

The emergence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae constitutes a serious problem because of the transfer of resistance genes from one organism to another.

Objectives

To screen the antibiotic susceptibility of E. coli and K. pneumoniae from inpatients at King Abdul- Aziz Hospital, Al-Taif, Saudi Arabia and to detect common ESBL genes, and random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) genotyping of the Enterobacteriaceae.

Methods

We analyzed 43 bacterial strains isolated from clinical samples of sporadic cases for their reactivity to different antibiotics. Strains that showed resistance by monoplex PCR were screened for ESBL TEM- and CTXM-1-, -2-, and -9-encoding genes. Random amplifications were used for typing the resistant strains.

Results

The majority of the ESBL containing strains were sensitive to meropenem, amikacin, gentamicin, and tigecycline. PCR detection using ESBL gene-specific primers showed that 17 of 43 strains harbored genes for ESBL TEM, CTX-M-1, or CTX-M-2. RAPD typing revealed marked variation among the ESBL-producing E.coli in relation to each other.

Conclusions

Considerably high incidence of ESBL-producing bacteria was present patients from the local area of Al-Taif and nearby cities in Saudi Arabia with TEM and CTX-M subtypes being the most commonly detected variants. There was evidence of a polymorphic genetic pattern among ESBL-producing bacteria.

Open access

Nayera E. Hassan, Sahar A. El-Masry, Rokia El-Banna, Salwa M. Elshebini, Muhamed Al-Tohamy, Salwa El-Batrawy, Nihad H. Ahmed, Dalia Adel, Enas Abdel Rasheed, Mohamed Selim, Mohamed S. El Hussieny, Aya Khalil and Manal Mouhamed Ali

Abstract

AIM: To evaluate body composition changes after use of three different types of obesity management protocols: dietary measures and physical activity; acupuncture or laser acupuncture with healthy diet; aiming at achieving stable weight loss among obese Egyptian females.

METHODS: A randomized longitudinal prospective study included 76 obese adult females; aged 26 up to 55 years. Anthropometric, body composition, ultrasonographic and biochemical assessments were done.

RESULTS: The three types of obesity management protocols showed significant improvement in body composition (decrease in fat% and increases in FFM and TBW) and visceral fat by US. However, nutritional intervention showed highly significant improvement in the skin fold thickness at triceps and biceps sites and peripheral adiposity index. Acupuncture intervention showed highly significant improvement in fasting blood glucose (decreased) and lipid profile (decreased triglycerides, total cholesterol and LDL, and increased HDL). Laser intervention showed highly significant improvement in all the skin fold thickness and some parameters of lipid profile (decreased total cholesterol and LDL).

CONCLUSIONS: The three obesity management protocols have significant effect on body composition, but acupuncture has the best effect in improving the lipid profile and fasting blood sugar. In addition, Laser intervention was recommended to improve skin fold thickness and subcutaneous fat.