Samir Al Shariff

Novel wind tunnel for power generation

Novel wind tunnel with conical and elevation structure is proposed and demonstrated for power generation. The tunnel is evaluated and characterized using sucking fan which is placed at the front end to simulate available wind in the atmosphere. A wind turbine is placed at the back end of the tunnel to generate electricity. The tunnel structure is made up from galvanized aluminum with square front and back ends with side length of 0.75 m and 0.5 m, respectively. The elevation of the tunnel measured from center to center of the front end and back end is 1.5 m. The used wind turbine in the tunnel has 48 cm diameter blades made up from aluminum. The average monthly wind speed in Medina, KSA is 5.5 m measured over 10 years. This wind speed was used in the analysis of the wind tunnel.

Wind speed numerical simulation calculations for novel wind tunnel

Numerical simulations were conducted to calculate wind speeds at different position for recently proposed novel tunnel with conical shape and elevation height change structure. Wind speeds were compared with those for a straight conical tunnel with no elevation height change. Different wind speeds were applied at the inlet of the tunnel which represent the measured data for Medina, Saudi Arabia. The numerical simulations showed better performance of the novel tunnel compared to straight conical structure.

Hybrid Wind/Electric Powered Vehicle

Hybrid wind/electric powered vehicle is built and demonstrated. The vehicle uses bank of batteries to drive it. The batteries drive 3-phase brushless DC motor which moves the vehicle. The motor can rotate up to 2900 revolution per minute (RPM) at 3HP. A wind turbine; that is mounted at 1.5m on the vehicle, uses wind energy to generate electricity and charges the battery bank. A smart charging subsystem is proposed to enable efficient charging of the batteries. The minimum required wind speed to enable battery charging is found to be around 200 RPM.

Large volume air plasma for fruit sterilization

Summary form only given. Large volume atmospheric pressure air plasmas [1,2] were generated by applying ~ 100 ns high voltage pulse between two parallel electrodes separated by 48 mm gap in air. The generated plasma frequencies can be varied from single pulse to 2000 Hz. A uniformly distributed stainless steel pens were welded to the high voltage electrode while the grounded electrode is a metallic flat disc. The pens have 32 mm length and 0.48 mm radius and separated by 8.7 mm to form a brush-shape. The pin tips are cut to form sharp ends to enhance the applied electric field and reduced the ignition voltage. The atmospheric pressure large volume glow discharges plasma ignite first at the outer pens forming luminousness circle then the internal pens ignited with the increase in the applied voltage. The glowed plasma expanded to cover the gap by increasing the applied voltage. Each pens form glow discharge with the ground electrode. The plasma intensity and homogeneity enhanced with increasing the applied voltage or the plasma frequency. The emission spectra investigations declared the main presence of nitrogen bands, second positive band and first negative band in the investigated range between 200 nm and 800 nm. The generated plasma was successfully proved as an efficacious tool for sterilizing a wide range of fruits from the naturally occurring bacterial and fungal contamination.

Characteristics of cold atmospheric pressure plasma jet and its antimicrobial activity

Cold atmospheric pressure plasma jet (CAPPJ) has been approved by several investigators as anti-microbial agent [1]. In this experiment, CAPPJ in air is generated by applying AC voltage 7-14 kV (peak-to-peak), with frequency of 21-29 kHz to Al2O3 tube. The tube has 150 mm length with a 4 and 6 mm inner and outer diameter, respectively. Argon flow rates ranged from 0.1 to 10 SLM were blown through the tube to form the plasma jet. The addition of oxygen to argon as operating gases enhances the generation of O and OH radicals. The electric and spectroscopic characteristics of the generated plasma jet were investigated. The generated plasma jet length and mode of operation varied as a function of oxygen flow rate percentage, applied voltage and frequency. The plasma jet length increases with argon flow rate to reach its maximum at 5 SLM then ceases to reach saturation at 8 SLM. The energies consumed by the discharge were estimated using the charge-voltage curve (Lissajous figure). The consumed energy increased with increasing the input power. Regarding the decontamination, the data indicate an optimum condition of E. coli sterilization at 0.02% of oxygen.

Double jet atmospheric pressure plasma as a decontaminating agent

Summary form only given. Atmospheric pressure plasmas jet are recently of high interest due to the promising biomedical applications. Double atmospheric pressure plasma jet system was used to disinfect date-palm fruits. The double jet was formed by blowing argon gas though ceramic alumina tube. It has two capillaries of 1 mm inner diameter for each and 31.5 mm outer diameter. The two capillaries are separated by 3.8 mm. The generated double jet plasma was characterized electrically, spectroscopically and photographically. A high voltage ~20 kHz sinusoidal wave was applied to a copper ring electrode surrounding the tube. The two jets were ignited simultaneously and homogeneous plasma is formed as indicated from the current waveform. Photographic investigation shows that the double plasma jet length increases with the increase in argon gas flow rate to reach optimum length at 3.5 l/min. However, the double jet shrinks with higher flow rates. The presence of OH, O radicles, excited nitrogen molecules and argon species were detected in the double jet spectra, at 3 mm from jet nozzle. The presence of reactive species nominated the double jet to be as sterilized tool. Therefore, the double jet plasma was successfully used to inactivate A. niger spores, inoculated onto sterilized date palm discs at different flow rate from 0.5 to 4.5 l/min. with optimum efficacy measured at 3.5 l/min which is probably related to the higher amount of reactive species, OH and O radicals.