Synthesis and characterization of novel Cu2O/PVDF nanocomposites for flexible ferroelectric organic electronic memory devices

Farag S. Al-Hazmi,Dago M. de Leeuw,A.A. Al-Ghamdi,F.S. Shokr 한국물리학회 2017 Current Applied Physics Vol.17 No.9

Copper oxide nanoparticles loaded Poly(vinylidene fluoride) (PVDF) nanocomposites, at concentrations from 1 to 9 wt%, were developed by casting technique. The effect of the Cu2O nanoparticles on the structure, thermal, mechanical and dielectric properties of the PVDF were inspected. The scanning electron microscopy (FE-SEM) revealed the well dispersion of the Cu2O nanoparticles into the PVDF matrix up to 5 wt%. The X-ray diffraction (XRD) patterns and the infrared spectroscopy (FTIR) measurements implied that the inclusion of the Cu2O nanoparticles into the PVDF matrix leads to a transform of the non-polar semi-crystalline a-phase of the neat PVDF to highly crystallized polar b-phase. Moreover, an increase of the thermal stability and crystallinity of the PVDF after the incorporation of the Cu2O nanoparticles was achieved. The Cu2O/PVDF nanocomposites exhibited excellent cyclic mechanical property compared to the neat PVDF. The introduction of 5 wt% Cu2O nanoparticles into the PVDF composites resulted in remarkable increase of the dielectric constant by 13 times while the dielectric loss was very low. A device based on Al/5 wt% Cu2O doped PVDF/Pt structure is developed. This device shows ferroelectric hysteresis with butterfly like shape and exhibited remanent polarization of 11.2 mC/cm2 with coercive field of 49 MV/m. These superior properties enable the developed Cu2O/PVDF nanocomposite films to be a potential candidate in the field of ferroelectric organic electronic memory devices.

Enhancement of heavy metals recovery from aqueous solutions by cementation on a rotating cylinder using a stationary wiper

M.S. Ahmed,T.M. Zewail,E-S.Z. El-Ashtoukhy,H.A. Farag,I.H. El Azab,F.A. Albatati,A.F. Al-Hossainy,M.Sh. Zoromba,M.H. Abdel-Aziz 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.97 No.-

The goal of the present research is to study the impact of a stationary wiper almost touching a revolvingzinc solid cylinder on the rate of Cu+2 cementation. Initial Cu+2 ions concentration, speed of rotation, andthe effect of the presence and absence of a wiper were investigated. The degree of Cu+2 cementation wasstated in relation to the mass transfer coefficient which was valued under diverse circumstances. Thepresent study showed that the mass transfer coefficient accelerates as rotation speed and quantity of Cu+2increase. The presence of a wiper enhances the degree of Cu+2 cementation by an extent that varies from1.59 to 64% subject to the operational circumstances. The present mass transfer data have beeninterrelated by dimensionless equations. The importance of such relationships in the sizing and runningof rotating cylinders used for performing diffusion- restricted reactions is underlined.

Analysis of the electrical properties of p-n GaAs homojunction under dc and ac fields

A.A.M.Farag,M. Fadel,I.S. Yahia 한국물리학회 2012 Current Applied Physics Vol.12 No.6

In this work, the n-type GaAs films were grown on p-type GaAs single crystalline substrate by metal organic chemical vapor deposition (MOCVD). The temperature dependence of the current densityevoltage (J-V) characteristics of n-GaAs/p-GaAs homojunction contacts were measured in the temperature range 293-413 K. These characteristics showed a rectifying behavior consistent with a potential barrier formed at the interface. The forward current densityevoltage characteristics under low voltage biasing were explained on the basis of thermionic emission mechanism. The high values of ideality factor (n) may be ascribed to the presence of an interfacial layer. Analysis of the experimental data under the reverse voltage biasing suggests a dominant mechanism was found to be a Schottky effect. The impedance properties and the alternating current (ac) conductivity of n-GaAs/p-GaAs homojunction were investigated as a function of frequency and temperature. The ac conductivity was found to obey the universal power law. The variation of the exponent s with the temperature suggested that the conduction mechanism is an overlapping large-polaron tunneling (OLPT) model associated with correlated barrier hopping (CBH) model at the higher temperature

Current Transport and Capacitance-Voltage Characteristics of n-InSb/p-GaP Prepared by Flash Evaporation and Liquid Phase Epitaxy

A.A.M.Farag,F. S. Terra,G. M. M. Fahim,A. A. M. Mansour 대한금속·재료학회 2012 METALS AND MATERIALS International Vol.18 No.3

In this paper, n-Type of InSb films were successfully fabricated on p-GaP monocrystalline substrates by both flash evaporation technique and liquid phase epitaxy to study some features of current transport in strained heterojunctions. The elemental composition of the prepared films was confirmed by energy disper-sive X-ray (EDX) spectroscopy. The morphology of the films was characterized by scanning electron microscopy (SEM). The electrical properties of the n-InSb/p-GaP junctions prepared by flash evaporation and liquid phase epitaxy were investigated through capacitance-voltage and current-voltage measure-ments, performed under dark condition in the temperature range 300-400 K. Due to misfit dislocations, the interface showed rectifying behavior. At low voltages, current in the forward direction was found to obey the diode equation and the conduction was controlled by a thermionic emission mechanism. For relatively higher voltages, conduction was dominated by a space-charge-limited conduction mechanism with single trap level. This is evidence of a depletion of the space charge region due to Fermi level pinning by sur-face states at the InSb/GaP interface. Junction parameters of the n-InSb/p-GaP like ideality factor and bar-rier height were obtained and variations were monitored as a function of temperatures. Also, an attempt to explore the governing current flow mechanism was made.

Synthesis and Antiviral Activity of 3-Aminoindole Nucleosides of 2-Acetamido-2-deoxy-D-glucose

Abdel-Rahman, Adel A.H.,El-Latif, Mona M. Abd,El-Essawy, Farag A.,Barakat, Yousif A. Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.10

A new method for the construction of 3-aminoindole nucleosides of 2-acetamido-2-deoxy-D-glucose based is presented. Nitration and acetylation of the indole nucleosides by acetic anhydride-nitric acid mixture followed by reduction using silver catalyst (SNSM) impregnated on silica gel, afforded the corresponding amino indole nucleosides. The nucleosides were tested for antiviral activity against hepatitis B virus (HBV) to show different degrees of antiviral activities or inhibitory actions.

A Comprehensive Large-Wind-Turbine Emulator for Accurate Wind-Energy Harvest Evaluation

Farag Wael A.,Hemeida Ahmed M.,Mahgoub Osama A. 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

Robust modeling and emulation are required to support the design of ultra-wind turbines and analyze the efects of various factors, parameters, and environmental disturbances. The models that are constructed based on pure computational methods, in which the entire emulator is created in computational software are cost-efective, and their speed depends on the employed computation platform. However, these methods' practical signifcance and accuracy are considerably lower than that of the combined physical and computational platform methods. Therefore, A comprehensive 5 MW wind turbine emulator’s design and implementation are investigated thoroughly in this paper. A separately excited DC motor set under the control of a current-controlled drive forms the basis of the suggested emulation. The emulation algorithms that simulate the features of the 5 MW wind turbine are executed on a digital signal processor. These algorithms regulate the DC motor's current, which in turn regulates the torque. The results obtained demonstrate that the system was successful in accurately simulating the transient and steady-state characteristics of the 5 MW wind turbine. The emulator system was initially tested and validated with simulation results using MATLAB/Simulink code attached to both the FAST and TurbSim models. Furthermore, step and stochastic wind profles were used to experimentally verify and test it. Nearly all of the power that is available in the wind turbine system is successfully acquired using the maximum power point tracking technique, which is used to fnd the optimum operating point. The developed wind turbine emulator can be used to precisely assess energy harvesting by examining various mechanical and electrical input/output values of the Permanent Magnet Synchronous Generator vastly used in ultra-large wind turbine nacelles.

First Report of Bacterial Wilt Caused by Ralstonia solanacearum Biovar 2 Race 1 on Tomato in Egypt

Mohamed A. A. Seleim,Kamal A. M. Abo-Elyousr,Kenawy M. Abd-El-Moneem,Farag A. Saead 한국식물병리학회 2014 Plant Pathology Journal Vol.30 No.3

This study aims to isolate and identify the causal pathogenof tomato bacterial wilt in Egypt. In 2008, tomato plants showing typical symptoms of bacterial wilt diseasewith no foliar yellowing were observed in Minia, Assiut and Sohag governorates, Egypt. When cut stems of symptomatic plants were submerged in water, whitishooze was evident and longitudinal sections showed a brown discoloration in the vascular tissues. Bacteria were isolated on triphenyl tetrazolium chloride medium and fifteen isolates shown typical morphological and cultural characteristics were confirmed as Ralstonia solanacearumbiovar 2 race 1. Pathogenicity tests showed that all isolates proved to be pathogenic to tomato plants, varied from 52 to 97% wilting. This is the first report of  R. solanacearum  biovar 2 race 1 causing bacterialwilt in tomato crop in Egypt.

Digital Image Watermarking Based On Joint (DCT-DWT) and Arnold Transform

Majdi Farag Mohammed El Bireki,M. F. L. Abdullah,li Abdrhman M. Ukasha,Ali A. Elrowayati 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.5

The researcher has adopted a digital watermarking technique which operates in the frequency domain: a hybrid watermarking scheme based joint discrete wavelet transform – discrete cosine transform – (DWT-DCT). Its main objective is to test whether this technique can withstand attacks (its robustness) and invisibility (its imperceptibility), achieved by taking DCT of the DWT coefficients of the LL mid-frequency sub-bands from its band. To ensure security, the secret code (watermark) is scrambled using the Arnold transformation which is embedded in the original host image; only gray-scale digital images are used. The results of this research reveal that the secret code (watermark) is strong enough against threats (noise). Comparative results are measured using signal-to-noise ratio criterions, mean square error and normalized cross correlation. Simulated experimentation is done in Matlab.

First Report of Bacterial Wilt Caused by Ralstonia solanacearum Biovar 2 Race 1 on Tomato in Egypt

Seleim, Mohamed A.A.,Abo-Elyousr, Kamal A.M.,Abd-El-Moneem, Kenawy M.,Saead, Farag A. The Korean Society of Plant Pathology 2014 Plant Pathology Journal Vol.30 No.3

This study aims to isolate and identify the causal pathogen of tomato bacterial wilt in Egypt. In 2008, tomato plants showing typical symptoms of bacterial wilt disease with no foliar yellowing were observed in Minia, Assiut and Sohag governorates, Egypt. When cut stems of symptomatic plants were submerged in water, whitish ooze was evident and longitudinal sections showed a brown discoloration in the vascular tissues. Bacteria were isolated on triphenyl tetrazolium chloride medium and fifteen isolates shown typical morphological and cultural characteristics were confirmed as Ralstonia solanacearum biovar 2 race 1. Pathogenicity tests showed that all isolates proved to be pathogenic to tomato plants, varied from 52 to 97% wilting. This is the first report of R. solanacearum biovar 2 race 1 causing bacterial wilt in tomato crop in Egypt.

Corrosion inhibition performance and computational studies of pyridine and pyran derivatives for API X-65 steel in 6 M H2SO4

Kurls E. Anwer,Ahmed A. Farag,Eslam A. Mohamed,Eman M. Azmy,Galal H. Sayed 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.97 No.-

The present investigation aims to synthesize and explore the influence of pyridine and pyran derivativeson the API X-65 steel corrosion in a 6 M H2SO4 solution. The compound was examined at differentconcentrations to optimized the best concentration for the corrosion inhibition effect, weight lossmeasurements, potentiodynamic polarization measurement (PDP), electrochemical impedance spectroscopy(EIS), scanning electron microscopy (SEM) and theoretical methods were used to evaluating theinhibition efficiency. The obtained adsorption data achieved the model of Langmuir isotherm. Thepyridine derivatives showed higher inhibition than pyran derivatives. The PDP tests proposed thatpyridine and pyran derivatives are mixed-type inhibitors. The EIS parameters demonstrate that thedouble-layer capacitance (Cdl) decreases with the increase of inhibitor concentration, which implies areduces dielectric constant. It was observed from experimental data that the inhibition efficiency reached92.7%, 89.1, 94.7, and 85.2% for concentration 2.66 10 3M of I, II, III and IV, respectively indicating theinhibition order is III > I > II > IV. The parameters derived from the theoretical quantum chemicalcalculations were found adequately correlated with the obtained experimental results.