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Open access

S. Mohamed, A. Abdeltawab and M. Shoeib

Abstract

Hydroxyapatite (HA) coatings were developed on titanium by electrophoretic deposition at various deposition potentials from 30 to 60 V and at a constant deposition time of 5 minutes using the synthetic HA (Ca10(PO4)6(OH)2,) powder in a suspension of dimethyleformamide (DMF, HCON(CH3)2). The electrochemical corrosion behavior of the HA coatings in simulated body fluid (SBF Hanks’ solution) at 37 °C and pH 7.4 was investigated by means of open-circuit potential (OCP) measurement and potentiodynamic polarization tests. The OCP test showed that the values OCP for the coated samples shifted to more noble potential than for uncoated titanium, especially after addition of dispersants. The polarization test revealed that all HA coated specimens had a corrosion resistance higher than that of the substrate, especially after addition of dispersants such as polyvinyl butyral (PVB), polyethylene glycol (PEG) and triethanolamine (TEA) to the suspension. The coating morphology after polarization, characterized by scanning electron microscopy (SEM), showed penetration of electrolyte into the HA coats. Bone bioactivity of the coatings was also studied by immersion of coated specimens in Hanks’ solution for 3 and 7 days. Apatite granules growth on the surface of the HA layers was observed.

Open access

Ibrahim S. Seddiek and Mohamed M. Elgohary

Abstract

Increasing amounts of ships exhaust gases emitted worldwide forced the International Maritime Organization to issue some restricted maritime legislation for reducing the adverse environmental impacts arising from such emissions. Consequently, ships emission reduction became one of the technical and economical challenges that facing the ships, operators. The present paper addresses the different strategies that can be used to reduce those emissions, especially nitrogen oxides and sulfur oxides. The strategies included: applying reduction technologies onboard, using of alternative fuels, and follows one of fuel saving strategies. Using of selective catalytic reduction and sea water scrubbing appeared as the best reduction technologies onboard ships. Moreover, among the various proposed alternative fuels, natural gas, in its liquid state; has the priority to be used instead of conventional fuels. Applying one of those strategies is the matter of ship type and working area. As a numerical example, the proposed methods were investigated at a high-speed craft operating in the Red Sea area between Egypt and the Kingdom of Saudi Arabia. The results obtained are very satisfactory from the point of view of environment and economic issues, and reflected the importance of applying those strategies

Open access

Mona Mohamed Kamal Hijazi

Abstract

Attention and visual perception are important in fencing, as they affect the levels of performance and achievement in fencers. This study identifies the levels of attention and visual perception among male and female fencers and the relationship between attention and visual perception dimensions and the sport performance in fencing. The researcher employed a descriptive method in a sample of 16 fencers during the 2010/2011 season. The sample was comprised of eight males and eight females who participated in the 11-year stage of the Cairo Championships. The Test of Attentional and Interpersonal Style, which was designed by Nideffer and translated by Allawi (1998) was applied. The test consisted of 59 statements that measured seven dimensions. The Test of Visual Perception Skills designed by Alsmadune (2005), which includes seven dimensions was also used. Among females, a positive and statistically significant correlation between the achievement level and Visual Discrimination, Visual-Spatial Relationships, Visual Sequential Memory, Narrow Attentional Focus and Information Processing was observed, while among males, there was a positive and statistically significant correlation between the achievement level and Visual Discrimination, Visual Sequential Memory, Broad External Attentional Focus and Information Processing. For both males and females, a positive and statistically significant correlation between achievement level and Visual Discrimination, Visual Sequential Memory, Broad External Attentional, Narrow Attentional Focus and Information Processing was found. There were statistically significant differences between males and females in Visual Discrimination and Visual-Form Constancy.

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

Mohamed M. Hefnawy, Mostafa S. Mohamed, Mohammed A. Abounassif, Amer M. Alanazi and Gamal A. E. Mostafa

Abstract

High performance liquid chromatography (HPLC) and second-order derivative spectrophotometry have been used for simultaneous determination of pravastatin (PS) and fenofibrate (FF) in pharmaceutical formulations. HPLC separation was performed on a phenyl HYPERSIL C18 column (125 mm × 4.6 mm i.d., 5 μm particle diameter) in the isocratic mode using a mobile phase acetonitrile/0.1 % diethyl amine (50:50, V/V, pH 4.5) pumped at a flow rate of 1.0 mL min-1. Measurement was made at 240 nm. Both drugs were well resolved on the stationary phase, with retention times of 2.15 and 5.79 min for PS and FF, respectively. Calibration curves were linear (R = 0.999 for PS and 0.996 for FF) in the concentration range of 5-50 and 20-200 µg mL-1 for PS and FF, respectively. Pravastatin and fenofibrate were quantitated in combined preparations also using the second-order derivative response at 237.6 and 295.1 nm for PS and FF, respectively. Calibration curves were linear, with the correlation coefficient R = 0.999 for pravastatin and fenofibrate, in the concentration range of 5-20 and 3-20 µg mL-1 for PS and FF, respectively. Both methods were fully validated and compared, the results confirmed that they were highly suitable for their intended purpose.

Open access

Mohamed A. Mattar, Mohamed A. El-Saadawy, Mamdouh A. Helmy and Hussien M. Sorour

Abstract

Surge flow irrigation is one of the irrigation techniques for controlling furrow irrigation. The aim of this study was to investigate the effect of surge furrow irrigation on water management compared with continuous irrigation for different tillage systems. An experimental field was treated with various tillage systems (mouldboard plough, chisel plough and rotary plough) and water irrigation application methods (continuous flow, control) in which irrigation water was applied continuously, and surge flow (3-surges, 4-surges and 5-surges) in which irrigation water was applied intermittently until it reached the tail end of the furrow. The results showed that water savings obtained using the surge technique were 18.58, 11.84 and 18.93% lower water use than with continuous flow, for the mouldboard, chisel and rotary ploughs, respectively. The 3-surges treatment with the rotary plough reduced the advance time by 25.36% from that for continuous irrigation. The 4-surges treatment with the mouldboard plough had the highest water application efficiency (88.13%). The 3-surges treatment with the rotary plough had the highest distribution uniformity (85.01%). The rotary plough did not cause as much soil aeration around the root system as the other tillage systems. The field research provided information about surge flow, aimed at reducing advance times and increasing irrigation efficiency.

Open access

I.A. Mohamed, G.S. Mohamed, E.Y. Abdul-Hafeez and O.H.M. Ibrahim

Summary

Ruellia simplex plant is grown for its aesthetic features including flowers, leaves and overall foliage appearance. The fig wax scale Ceroplastes rusci L. (Hemiptera: Coccidae) was detected for the first time in Egypt on R. simplex. Mineral oil, diazinon, thiamethoxam + chlorantraniliprole, and essential oils extracted from Acorus calamus and Petroselinum crispum, were compared for their ability to control the insect. Results indicated that reduction percentage increased gradually until day 7 after the treatment regarding adults, nymphs and their total. The maximum efficacy of the mineral oil, and thiamethoxam + chlorantraniliprole, was noticed 21 days after treatment, followed by A. calamus oil. Efficacy of P. crispum oil and diazinon reached more than 86% after 21 days and more than 90% 28 days after treatment. At 28 days, A. calamus oil reached its maximum efficacy. Plants treated with thiamethoxam + chlorantraniliprole were the tallest plants and possessed significantly higher number of branches and leaves, and leaf pigments followed by those treated with mineral oil or A. calamus oil. A. calamus oil and thiamethoxam + chlorantraniliprole were proved as promising compounds tested for the first time in controlling C. rusci.

Open access

Abdel-Rahman M.A. Mohamed, Faruk H. Abdel-Aziz, Moawd A. Mohamed and Ali Gobara

ABSTRACT

This experiment aimed at studying the effect of Sida Compound fertilizer containing seaweed extract, natural fertilizers, growth promoters and micronutrients in chelated form on growth, yield and berry quality of table grape ‘Early Superior’. Foliar application of Sida Compound at concentration 0.05 to 0.20%, three times in a season increased shoot length, leaf area and content of N, P and K in the leaves as well as total soluble solids and total sugar contents in fruits. Yield of fruits increased by 29 and 14%, depending on the season.

Open access

Mohamad Ahmad Khedr, Hatem Mohamed AL-Shannaf, Hala Mohamed Mead and Shaker Abd El-Aziz Shaker

Abstract

A study was done on the feeding behaviour, development indices, and biochemical response of 4th instar larvae of Spodoptera littoralis in which seven cotton genotypes were used: Giza86, Giza88, Giza92, 10229 × Giza 86, H10, Suvin, and Karshenseki. Castor bean leaves were used as the control. All the tested cotton genotypes decreased the feeding behavior of S. littoralis larvae in terms of consumption percentages, consumption rate (CR), growth rates (GR), efficiency of conversion of ingested and digested food (ECI and ECD), approximate digestibility (AD), and feeding deterrence (FDI) compared to the control. Additionally, all the tested cotton varieties prolonged the time taken for larval and pupal duration and reduced both the pupation percentages and the weight of the resulting pupae, as compared to the control. Giza86 recorded the lowest values of both larval growth index and fitness (7.31 and 1.05, respectively) while the genotype Suvin recorded the lowest standardised growth index (0.020) more than other genotypes and the control that gave 10.16, 1.53, and 0.032, respectively. There was a significant inhibition in the level of both total soluble protein and total lipids, and activities of amylase and the trehalase enzymes in all the tested varieties, compared to that found in the control.

Open access

Saied Jafari, Mahdi Ebrahimi, Yong M. Goh, Mohamed A. Rajion, Mohamed F. Jahromi and Wisam S. Al-Jumaili

Abstract

A wide range of plant secondary metabolites (PSM) have been shown to have the potential to modulate the fermentation process in the rumen. The use of plants and plant extracts as natural feed additives has become an interesting topic not only among nutritionists but also other scientists. Although a large number of phytochemicals (e.g. saponins, tannins and essential oils) have recently been investigated for their methane (CH4) reduction potential, there have not yet been major breakthroughs that could be applied in practice. However, the effectiveness of these PSM depends on the source, type and the level of their presence in plant products. The aim of the present review was to assess ruminal CH4 emission through a comparison of integrating related studies from published papers, which described various levels of different PSM sources being added to ruminant feed. Apart from CH4, other related rumen fermentation parameters were also included in this review.