Time filter

Source Type

Arish, Egypt

Fouda A.S.,Mansoura University | Tawfik H.,Egyptian Electricity Holding Company | Abdallah N.M.,Mansoura University | Ahmd A.M.,Alex University
International Journal of Electrochemical Science | Year: 2013

Some indole derivatives are investigated as corrosion inhibitors for nickel in 0.5 M HCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. A significant decrease in the corrosion rate of nickel was observed in the presence of investigated indole derivatives. Potentiodynamic polarization curves revealed that these inhibitors acted as mixed-type inhibitors, affecting both cathodic and anodic corrosion processes. The adsorption of the inhibitors on nickel surface in 0.5 M HCl was found to follow Frumkin adsorption isotherm. Thermodynamic adsorption parameters (Kads, δG°ads) of investigated inhibitors were calculated from the linear form of Frumkin adsorption isotherm. Activation parameters of the corrosion process were calculated and discussed. EIS was used to investigate the mechanism of corrosion inhibition. Correlation between the inhibition efficiency and the structure of these inhibitors are presented. Source

Bayoumy Aly A.M.,Military Technical College MTC | Rezeka S.F.,Alex University
International Review of Mechanical Engineering | Year: 2013

Some articulated robotic manipulators, such as ED-7220C robotic arm, have most of their actuators located at the robot base. Power is transmitted from the motors via spur gears and timing belts to robot links. Consequently, the motion of robotic links are not related to each other, but related to the base of the robot. This kind of robot designs has many advantages, but the main disadvantage is that the links may collide with each other due to geometric constrains. Collisions consume the operator's awareness, exertion, and also consume time. Collision avoidance algorithm is developed and presented. A simple GUI is also developed to provide an easy way to drive the robot. The developed algorithm is tested to the robot and shows a good response with zero collision under normal operating conditions. © 2013 Praise Worthy Prize S.r.l. - All rights reserved. Source

Attia E.M.,Alex University Alex | Mohamed M.F.,Alex University Alex | Maharem N.A.,Alex University
International Review of Mechanical Engineering | Year: 2013

Ride with comfort is the most important demand in vehicle industry as it affects directly seats mounting. For that reasons a lot of effort has been made to improve ride comfort by isolating vehicle from road irregularities as possible. That can be done by improving vehicle suspension ability to dampen the vibration induced from road irregularities during vehicle maneuver before it reaches the vehicle body. This work investigates the effect of active damping on vehicle vibrations by presenting mathematical model of full active vehicle suspensions. That model introduced a new active damper tested recently and proved to be efficient. These dampers depend on two kinds of fluids, Electro-Rheological fluid (ER) and Magneto- Rheological fluid (MR), both of them give high damping with a little power cost. Mathematical model is derived for the vehicle suspended by a classical damper or Electro- Rheological (ER) damper. Many types of roads are tested for vibration effect on the driver and suspension of the vehicle. A computer programs are constructed which include a classical damper or (ER) damper and can be implemented on a full vehicle suspension. Also a simulation program (MATLAB-SIMULINK) from which any response to any changes in any parameter can be obtained. A comparison between the types of roads as effect for heave, front and rear wheel suspension was studied. Also effect of voltage input to (ER) damper on vibrations of the vehicle was investigated. © 2013 Praise Worthy Prize S.r.l. - All rights reserved. Source

Fouda A.S.,Mansoura University | El-Azaly A.H.,Nile higher institute for engineering and technology | Awad R.S.,Mansoura University | Ahmed A.M.,Alex University
International Journal of Electrochemical Science | Year: 2014

Inhibition of carbon steel corrosion by some benzonitrile azo dyes in 1 M HCl has been studied using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. The electrochemical measurements showed that the inhibition efficiency increased by increasing the inhibitor concentration. The potentiodynamic polarization measurements indicated that the inhibitors are of mixed type. The results of EIS indicate that the corrosion resistance of the adsorption film formed by inhibitor on metal surface has increased. EFM can be used as a rapid and non-destructive technique for corrosion rate measurements without prior knowledge of Tafel constants. The results obtained from the three different techniques were in good agreement. © 2014 by ESG. Source

Alsafy M.A.,Alex University | El-Shahat K.H.,Cairo University
Journal of Applied Biological Sciences | Year: 2011

Morphological Evaluation of Ovary in Relation to Recovery, Quality of Oocytes and Steroid Production in Sheep Mohamed A.M. ALSAFY 1K.H. EL-SHAHAT2 1Anatomy and Embryology department, Fac.Vet. Med., Alex. Univ., EGYPT 2Theriogenology department, Fac.Vet. Med., Cairo Univ., EGYPT The purpose of current study was to evaluate the effect of follicles, corpus luteum (CL) and steroid production (progesterone and estradiol) on the morphology of sheep ovaries, with the view of in vitro recovery, quality, and maturation of oocytes. Fifty ovarian pairs grouped into right, and left, CL bearing and non-CL -bearing ovaries were used in the current study. The weight, length, width and thickness of ovaries were recorded. The follicles were classified into 3 groups small (>2mm), medium (2-4mm) and large (>4mm) follicles. Oocytes were classified according to their morphology into 3 grades COCS (Compact cumulus oocyte complexes), POCS (Partially invested with less than three layers of cumulus cells), DO (denuded oocyte). The concentration of progesterone and estradiol 17β in the follicular fluid were estimated. The dimensions of ovaries between right and left ovaries were not significantly different. However, the ovarian dimensions as well as their weight was significantly (P < 0.05) affected by presence of CL, being higher in CL bearing ovary than that of non-CL bearing ovary. The average number of large follicles were significantly (P < 0.05) increased in the right ovary (1.0±0.14) when compared to the left ovary (0.6±0.10). The recovered COCs number was found to be significantly higher (P < 0.05) in the right than left ovaries (2.0±0.13; 1.2 ±0.09 respectively). A greater number of vesicular follicles and aspirated COCS were found in non-CL bearing ovary (5.0 ±0.97;1.25±0.09 respectively) than in CL bearing ovary (3.0±0.67;0.80±0.13 respectively). The CL-absent ovaries provide large numbers as well as high quality of COCs when compared to CL-present ovaries and that CL-absent ovaries can be used to collect quality COCs for in vitro production of sheep embryos. Source

Discover hidden collaborations