Basic Science Sector

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.

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.

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.

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

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.

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.

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

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.

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.

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.

The electrocatalytic oxidation of formic acid (FA) at PtAu nanoparticle (NP)-modified glassy carbon (GC) electrode has been investigated. The catalytic activity toward the electrooxidation of FA was greatly influenced by the method of the electrode preparation. The highest catalytic activity was obtained on Pt/Au/NH2/GC electrode in which the GC electrode was chemically modified with gold nanoparticles (AuNPs) anard Ptnanopticles (PtNPs) were next electrochemically deposited on top of AuNPs.

An efficient and easy preparation of enamine derivatives, via active methyl and methylene compounds by in situ-generated 1-(diethoxymethyl)piperidine, produced from the mixture of triethyl orthoformate/piperidine/DMF, are described. Some new pyridazinone derivatives have been synthesized from the reaction of enamines with hydrazine hydrate and cyanoacid hydrazide.

Novel N-arylpyrazole-containing enaminones 2a,b were synthesized as key intermediates. Reactions of 2a,b with active methylene compounds in acetic acid in the presence of ammonium acetate afforded substituted pyridine derivatives 5a-d. Enaminones 2a,b also reacted with aliphatic amines such as hydrazine hydrate and hydroxylamine hydrochloride to give bipyrazoles 8a,b and pyrazolylisoxazoles 9a,b, respectively. On the other hand, treatment of 2a,b with a heterocyclic amine and its diazonium salt yielded the respective [1,2,4]triazolo[4,3-a] pyrimidines 12a,b and pyrazolylcarbonyl[1,2,4]triazolo[3,4-c] [1,2,4] triazines 14a,b. Moreover, 2-thioxo-2,3-dihydro-1H-pyrido[2,3-d]pyrimidin-4-one (17) was prepared via reaction of enaminone 2a with aminothiouracil (15). Cyclocondensation of 17 with the appropriate hydrazonoyl chlorides 18a-c gave the corresponding pyrido[2,3-d][1,2,4]triazolo[4,3-a]pyrimidin-5-ones 21a-c. The cytotoxic effects of compounds 2b, 14a and 17 against human breast cell line (MCF-7) and liver carcinoma cell line (HEPG2) were screened and in both lines they showed inhibition effects comparable to those of 5-fluorouracil, used as a standard. The antimicrobial activity of some products chosen as representative examples was also evaluated.

Fine-structure energy levels, oscillator strengths and transitions probabilities for transitions among the fine-structure levels of the terms belonging to the 1s22s22p63s2np (2P), 1s22s22p63s2nd (2D) (n= 3-5) and 1s22s22p63s2ns (2S), 1s22s22p63s2nf (2F) (n= 4, 5) configurations of the Al-like ions Ar VI, K VII, and Ca VIII have been calculated. The calculations are based upon the general configuration interaction code CIV3 of Hibbert. Calculated values are compared with experimental and other theoretical results where some unpublished energy values and oscillator strengths are reported.

Chitin is the second most abundant carbohydrate polymer in nature next to cellulose. The main source of chitin is crustacean shells. Chitosan, derived from chitin by alkaline deacetylation, characteristically plays an important role in applications. Several parameters determine the chitosan specifications, namely, chitosan sources, incubation time, pretreatment conditions, temperature and acid and alkaline treatment. Chitosan extraction has been achieved by microwave heating and compared with that of conducting the deacetylation in an autoclave. High molecular weight chitosan (as determined by viscosity measurements of chitosan in dilute acetic acid solution), white color

Fourteen fungal species (Alternariaalternata, Aspergillus-candidus, Aspergillusflavus, Aspergillusniger, Aspergillus-ochrochus, Botrytis cinerea, Chaetomiumglobosum, Fusar-iummoniliforme, Fusariumoxysporum, Fusariumsolani, Penicilliumchrysogenum, Penicilliumfuniculosm, Penicill-iumitalicum and Phanerochaetechrysosporium) belonging to Ascomycete, Basidiomycete and Deuteromycete groups were isolated from composted soil in Egypt. The ability of laser induced plasma as a new technique to enhance fungal degradation efficiency of starch based plastic polymer was tested. The maximum significant plastic degradation activities for all isolated fungal species were showed after the lowest exposure time (5 min) to laser induced plasma. The highest efficient fungal degraded starch based plastic polymer was A. niger, where the initial appearance of clear zone was recorded only after two days accompanied with the highest significant amylotic activities. The evaluation of changes in starch based plastic polymer degraded by A. niger compared with uninoculated and non plasma treated A. niger degraded starch based plastic polymer was observed by scanning electron microscope (SEM). The maximum degradation efficiency accompanied with the highest loss of tensile strength (90 and 80.7%, respectively) was observed in the plasma treated A. niger degrading starch polymer. Four low molecular weight sugars were detected by HPLC in plasmaand non plasma treated A. niger degrading plastic polymer.