Export 641 results:
Sort by: Author Title Type [ Year  (Asc)]
Gra, M. P. F., H. Fawzy, Y. Badr, M. M. Elokr, C. Nico, R. Soares, L. C. Costa, and M. A. Valente, "Electrical, Dielectric and Structural Properties of Borovanadate Glass Systems Doped With Samarium Oxide", phys status solidi C, 2011. Abstract

Glasses doped with rare earth (RE) ions are widely studied due to the numerous applications of these systems (active media for solid state lasers, optical telecommunication non-linear optical materials, electro-optic devices, etc.). Boron trioxide, B2O3, is a known glass forming oxide with a relative low melting temperature. The addition of a transition metal oxide, such as V2O5, promotes the exhibition of semiconducting properties making these promising systems for several technological applications, such that ones involved in solar energy conversion devices. It is known that alkali borovanadate glasses, like alkali borate glasses themselves, are ionically conducting materials. Despite their importance there are only few studies on these glasses reported on literature. Thus, the alkali-borovanadate glass system constitutes a family with high interest from the electrical and dielectric point of view. The effect of the increment of alkali quantity in the electrical and dielectric response of these glasses and the physical/structural explanation are questions which will be addressed. In this work, the transparent glass samples with molar composition 0.01Sm2O3- 0.99[0.85B2O3-(0.15-x)Li2O-xV2O5] with x = 0, 0.1, 0.2, 0.35, 0.5 and 2 (mol %) were prepared by conventional melting technique. The prepared samples were fullycharacterized using different experimental techniques such as, differential thermal analysis (DTA), X-ray diffraction (XRD), electrical and dielectric measurements. The samples structure, electrical and dielectric properties as a function of vanadium ions content was explored and discussed.

Frag, E. Y. Z., G. G. Mohamed, and H. M. S. Alelaiwi, "Electroanalytical determination of sildena?l in Viagra tablets usingscreen-printed and conventional carbon paste electrodes", J. of Electroanalytical Chemistry, 2011.
El-Deab, M. S., L. A. Kibler, and D. M. Kolb, "Electrocatalytic oxidation of CO at Pt modified with manganese oxide nanorods", Electrocatalysis, 2011. Abstract

CO oxidation at Pt anodes modified with manganese oxide nanorods (nano-MnOx/Pt) has been studied by cyclic and linear sweep voltammetry. Both CO adlayer stripping and oxidation of bulk CO are enhanced by nano-MnOx as compared to unmodified Pt electrodes. This is manifested by a negative shift of ca. 200 mV in the peak potential of CO adlayer stripping at the modified compared to the unmodified Pt surface. This enhancement is attributed to the catalytic -MnOOH single?mediation of manganese oxide nanorods (electrodeposited in a crystalline phase,) which supplies oxygen species at relatively low anodic potentials and thus facilitates the oxidation of CO to CO2. This finding sheds new light on the formic acid oxidation in the presence of MnOx, as the latter can remove CO efficiently from the Pt surface and hence prevents its de-activation.

Heakal, E. - T. F., A. M. Fekry, and A. E. - B. M. Jibril, "Electrochemical behavior of the Mg alloy AZ91D in borate solutions", Corrosion Science, 2011. Abstract
Heakal, E. - T. F., A. M. Fekry, and A. E. - B. M. Jibril, "Electrochemical behavior of the Mg alloy AZ91D in borate solutions", Corrosion Science, 2011.
Ame, M. A., A. M. Fekry, and S.M.Shanab, "Electrochemical Behavior of Titanium Alloy in 3", Int. J. Electrochem. Sci., 2011. Abstract

Marine environment is a complex corrosive system and presence of red algae is one of the factors that influence corrosion processes. Biofouling is one of the major impediments in the use of titanium in sea-water cooled condensers of power plants, which is otherwise an excellent material with respect to corrosion resistance. Electrochemical impedance spectroscopy (EIS) experiments were carried out in 3.5% NaCl to study the corrosion inhibition effect of red algal extracts on Ti-6Al-4V surfaces. The results indicated that the type of extract, the extract concentration and the immersion time affect the inhibition efficiency (IE%). In general, corrosion rate for J1, J2 and J3 [Successive extractions by hexane (J1), ethyl acetate (J2) and methanol (J3)] decreases with increasing its concentration or immersion time. The order of IE% was found to be J3 ? J1 ? J2. Langmuir adsorption isotherm was found to fit well the experimental data. Values were calculated for the adsorption process and it is seemed to be in the order of: J3 (365.66 ppm-1) ? J1 (150.42 ppm-1) ? J2 (58.35 ppm-1).

El-TaibHeakal, F., A. A. Ghoneim, and M. K. A. S. Awad, "Electrochemical Behaviour Of Ti", Corrosion Science, 2011.
Heakal, E. - T. F., and K. A. Awad, "Electrochemical Corrosion and Passivation Behavior of Titanium and Its Ti-6Al-4V Alloy in Low and Highly Concentrated HBr Solutions", Int. J. Electrochem. Sci., 2011. Abstract

Passivation and dissolution behavior of Ti and Ti-6Al-4V alloy was investigated in HBr solutions over a wide concentration range from 0.01 M to 8.0 M using open-circuit potential, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. In the low and high concentration domains, the open-circuit potential for the metal and its alloy was found to increase positively with time due to oxide film thickening on the metal surface. However, there is a certain critical HBr concentration at which the thickening rate of the oxide film on Ti metal has a maximum value. The results were confirmed by EIS measurements at open-circuit potential where a constant phase element model with its complex transfer function were used to analyze the obtained impedance responses. Polarization scans showed that the corrosion current density (icorr) for titanium decreases slightly with increasing HBr concentration up to the threshold value before it starts to increase appreciably. On the other hand, for Ti-6Al-4V alloy the value of icorr increases gradually with HBr concentration over the whole range, and the alloy dissolves actively due to its poor passivating ability. Interestingly, for the two materials both icorr and the critical current density of passivation (icrit) decrease with raising temperature, indicating a decrease in the corrosion susceptibility of the passivating oxide film as a result of the decrease in the extent of Br- anion adsorption at higher temperatures. The apparent activation energy for the thickening process of the passive film was calculated from the increase in the spontaneous growth rate (?1) of its inner layer with temperature. The results in general confirmed that Ti metal has a stronger propensity to form passive film in HBr solutions better than its Ti-6Al-4V alloy.

Morsi, M. S., A. A. Al-Sarawy, and S. W. A. El-Dein, "Electrochemical degradation of some organic dyes by electrochemical oxidation on a Pb/PbO2 electrode", Journal Desalination and Water Treatment, 2011.
S.A, A. - G., O. K. A., M. M., and B. A. M., "Electrochemical Degradation of Some Pesticides in Agricultural Wastewater", American Science, 2011. Abstract

This work deals with the possibility of using graphite electrodes for theelectro-catalytic oxidation process of some pesticides (malathion, imidaclopridand chlorpyrifos). The graphite electrodes were used in the combined process inthe presence of transition metals modified kaolin catalyst.

S.A, A. - G., O. K. A., M. M. M., and B. A. M., "Electrochemical Degradation of Some Pesticides in Agricultural Wastewater by using Modified Electrode", American Science, 2011. Abstract

This work deals with the possibility of using Ti/Rh-modified electrode forthe electrocatalytic oxidation process of some pesticides (malathion, imidacloprid and chlorpyrifos). The Ti/Rh-modified electrode was prepared by brushing of rhodiumnitrate solution on preanodized titanium substrate and annealing.

Atta, N. F., A. Galal, and S. M. Azab, "Electrochemical Determination of Paracetamol Using Gold Nanoparticles ", Int. J. Electrochem. Sci. 6: 5082-5096 (2011) IF:2.808, 2011.
Fekry, A. M., and M. A. Ameer, "Electrochemical Investigation on the Corrosion and Hydrogen Evolution Rate of Mild Steel in Sulphuric Acid Solution", International Journal of Hydrogen Energy, 2011. Abstract
Atta, N. F., A. Galal, and S. M. Azab, "Electrochemical Morphine Sensing Using Gold Nanoparticles Modified Carbon Paste Electrode", Int. J. Electrochem. Sci. 6: 5066-5081(2011) IF:2.808, 2011. Abstract

Morphine (MO) is frequently used to relieve severe pain for patients, especially for those who undergo a surgical procedure. However, when overdosed or abused, MO is toxic and can cause disruption in the central nervous system. Therefore, to prevent overdose-induced toxication, it is necessary to sensitively determine the concentrations of MO in patient's blood or urine. An easy-to-use approach for directly electrodepositing gold nanoparticles onto carbon paste electrode (CPE) to construct gold nanoparticles modified carbon paste electrode (GNMCPE) is performed. The electrochemistry of MO is investigated by cyclic voltammetry

Heakal, F. E. - T., and Z. M. Fatayerji, "Electrochemical performance of Mg", Journal of Solid State Electrochemistry, 2011. Abstract

A systematic study on the corrosion and passivation behavior of AZ91D alloy in relation to the influence of concentration, temperature, pH, and immersion time was made in aqueous sulfate solution using electrochemical techniques including open-circuit potential, potentiodynamic polarization and impedance spectroscopy.

Fekry, A. M., and M. A. Ameer, "Electrochemistry and Impedance Studies on Titanium andMagnesium Alloys in Ringer", International Journal of Electrochemical Science, 2011.
Hassan, H. B., and A. Z. Hamid, "Electrodeposited Cu", Int. J. Electrochem. Sci., 2011.
Hassan, H. B., and A. Z. Hamid, "Electrodeposited Ni-Cr2O3 Nanocomposite Anodes for Ethanol Electrooxidation", International Journal of Hydrogen Energy, 2011. Abstract
Hassan, H. B., and A. Z. Hamid, "Electrodeposited Ni-Cr2O3 Nanocomposite Anodes for Ethanol Electrooxidation", International Journal of Hydrogen Energy, 2011. Abstract

Nanocomposite coatings of Ni-Cr2O3 supported on carbon electrodes have been prepared by electrodeposition technique from nickel Watts bath in presence of Cr2O3 nanoparticles. Their electrochemical catalytic activities have been evaluated towards electrooxidation of ethanol in 1.0 M NaOH solution by using cyclic voltammetry, chronoamperometry and Tafel plots. The performance of the prepared anodes towards electrooxidation of ethanol as a function of co-deposited Cr2O3 content was studied. The catalytic activity of fabricated electrodes increases with increasing the volume fraction percent (Vf%) of Cr2O3 in the deposited film up to 7Vf%. The Ni-Cr2O3/C (7Vf%) electrode displayed significantly enhanced catalytic activity and stability towards electrooxidation of ethanol compared with Ni/C electrode. The kinetic parameters of Ni(OH)2/NiOOH and ethanol oxidation at Ni/C and Ni-Cr2O3/C electrodes have been evaluated.

Hassan, H. B., and A. Z. Hamid, "Electroless Ni-B supported on carbon for direct alcohol fuel cell applications", International Journal of Hydrogen Energy, 2011. Abstract
Hassan, H. B., and A. Z. Hamid, "Electroless Ni-B supported on carbon for direct alcohol fuel cell applications", International Journal of Hydrogen Energy, 2011. Abstract

Ni-B coatings were deposited by electroless technique onto the surface of commercial carbon electrodes for direct alcohol fuel cell applications. An acidic bath having nickel chloride as a source of nickel and dimethyleamine borane (DMAB) as a reducing agent was used to prepare the electroless Ni-B

Mohamed, B. F., A. M. Gouda, and L. Z. Ismail, "Electron Dynamics in Presence of Static Helical Magnet Inside Circular Waveguide", IEEE transactions on plasma science, 2011. Abstract

The dynamics of an electron in the fields associated with a TE electromagnetic wave propagating inside a circular waveguide is analytically studied. The motion of this electron along the axis of the waveguide is investigated in the existence of a helical magnet (in which the field is perpendicular to the axis of the waveguide and rotating as a function of position along the magnet). It is shown that it can be accelerated due to its interaction with polarized fields of microwave radiation propagating along the waveguide. The fields for the lowest order TE11 modes and the deflection angle of electron trajectory, due to these fields, are obtained. Also, an expression of the acceleration gradient of the electron and its energy gain are evaluated for different intensities and frequencies of the microwave.

Refaie, A. I., and A. A. Farrag, "Electron Impact Collision Strengths for Fe Xvi", International Review of Physics (IREPHY), 2011. Abstract

The energy levels and electron impact collision strengths have been calculated for Na- like irron.The MCDFGME package has been used in generating the relativistic wave functions and in calculating the energy levels and the plane wave Born (PWB) cross sections for the impact excitation.

Mostafa, H., M. F. Shibl, R. H. Hilal, L. I. Ali, and S. A. Halim, "Electronic Absorption Spectra of Some Triazolopyrimidine Derivatives", International Journal of Spectroscopy, 2011. Abstract

The electronic absorption spectra of triazolo pyrimidine and some of its derivatives were measured in polar as well as nonpolar solvents. Assignment of the observed transitions is facilitated via molecular orbital calculations. Charge density distributions, dipole moments, and the extent of delocalization of the MOS were used to interpret the observed solvent effects. The observed transitions are assigned as charge transfer (CT), localized, and delocalized according to the contribution of the various configurations in the CI-states. The correspondence between the calculated and experimental transition energies is satisfactory.

Hilal, R. H., M. F. Shibl, and M. El-Deftar, "Electronic Structure of Some A3 Adenosine-Receptor Antagonist", International Journal of Spectroscop, 2011. Abstract