Archives-June 2013

The Schiff base, 3-(-1-(2-pyrimidinylimino)methyl-2-napthol with NO chromophores have been synthesised and its Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes isolated. The ligand coordinates to the metal ions in the ratio 2L: 1M, through the azomethine N and napthol O atoms, resulting in N2O2 chromophores around the central metal atom. The % metal, infrared (IR) and electronic spectral measurements are consistent with the adoption of a 4-coordinate square planar/ tetrahedral geometry for the metal complexes. The infrared spectra show lone vC=N, vM-N and vM-O bands for the metal complexes in the range 1649-1655 cm-1, 579-599 cm-1 and 410-497 cm-1 respectively, indicative of the existence of geometric isomerism, and the complexes are in the cis-isomeric forms. Further evidence of coordination is the higher melting points of the complexes in the range 237-301oC in comparison with that of the ligand at 92-94oC. The in-vitro antibacterial studies show that the Schiff base and its Zn(II) complex exhibit broad-spectrum antibacterial activities against Bacillus cereus, Pseudomonas aeruginosa, Klebsiella oxytoca, Staphylococcus aureus and Proteus mirabilis like ciprofloxacin (30.0-50.5 mm) with inhibitory zones range of 14.0-20.0 and 12.0-17.5 mm respectively in the same assay.

Synthesis, spectroscopic (IR and electronic) and in-vitro antibacterial properties of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) complexes of the enolimines derived from condensation of p-nitroaniline and benzoyl trifluoroacetone (HL1) / theonyltrifluoroacetone (HL2) were reported. The ligands coordinated to the metal ions through the azomethine N and enol O atoms in ratio 1M: 1L, resulting in complexes of the type [ML1NO3].xH2O, [ML2(CH3COO)].xH2O and [PdL(Cl)H2O]. The IR and electronic spectral measurements were consistent with the adoption of a 4-coordinate square planar/ tetrahedral geometry for the metal complexes. The in-vitro antibacterial studies of the Schiff bases and their metal(II) complexes against Bacillus subtilis, Staphylococcus aureus, Proteus mirabilis, Klebsiella oxytoca, Pseudomonas aeruginosa, and Escherichia coli revealed that HL1 and its metal complexes were generally more active than HL2 and its complexes. Interestingly, [Zn(L1)NO3].½H2O, [Pd(L1)Cl(H2O)] and [Ni(L2)2] had broad-spectrum antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli with inhibitory zones range of 12.5-22.0 mm proving their potential usefulness as broad-spectrum antibacterial agents.

In this paper, we consider the 2nth-order symmetric differential expressions with real-valued coefficients. We obtain a necessary and sufficient condition for the discreteness of the spectrum of 2nth-order self-adjoint differential operators.

A mut'atutalaaq is a title for the financial right that belongs to divorced women on the basis of the basis of Islamic teachings. However this right is deserved by the wife only if the divorce is applied by her husband and she herself was not culpable in the case Imamia jurists, supported by verses and narrations, have proposed three views on this right: 1) Most of them believe that it is obligatory for this right to be given to those whose intercourse has not taken place and the divorce dowry has not been fixed. 2) Some of them say that it is an obligatory grant for all of the divorced women. 3) Others say that it is an obligatory for this right to be given to all of the types of divorced women mentioned in surah Baqara ayah 236 and it is highly recommended (Mustahab) for it to be given to others as well. In this article, I have studied these statements and have mentioned citations for each of these.

Post weld heat treatment and subsequent aging (PWHTA) effect on dissimilar friction stir welding (DFSW) (AA2024-T6 to AA6351-T6) were investigated in the present study. The micro structural measurement techniques (Optical, SEM- EDS) have been employed to understand the precipitate distribution and the elements distribution in the Stirred zone (SZ). PWHTA on dissimilar FSWs shows better mechanical properties and pitting corrosion than as welded specimens. A post weld solution treatment at 5200 C for 1 hr and subsequent ageing at 1800 C for 12 hrs and 8 hrs aging time resulted in better mechanical and corrosion properties respectively than other conditions.

In this study, we have demonstrated that haemoglobin can be coupled to acid-treated multiwall carbon nanotubes in the presence of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDC) and assembled as haemoglobin–carbon nanotube (Hb–CNT) composites. Our observations of the electrochemical studies demonstrate that the electrochemical response of Hb–CNT assembled in the presence of EDC is much higher than that in the absence of EDC. It is evident that the direct electron transfer of haemoglobin could be effectively accelerated in the Hb–CNT assembly by using EDC on a glassy carbon electrode (GCE), and the relative electron transfer rate constant Ks is found to be 1.02 ± 0.05 s?1. The results of our studies illustrate that the assembly of haemoglobin–multiwall carbon nanotubes using EDC could provide a novel strategy to effectively facilitate the direct electrochemistry of heme-containing proteins, which could be further utilized as a promising biosensor for some specific biological substrate and related biological process.

In this work the combined effect of injector orientation and nozzle hole geometry on performance, emissions and combustion were analyzed. Experiments were carried out on a single cylinder DI diesel engine for different orientation of injector located nearer to intake and exhaust valve in the combustion chamber. Effects of increase in injector opening pressure and injection timing advance were also analyzed. Experiments were carried out by plugging one of the two injector mounting holes. It was observed that for the injector located nearer to the exhaust valve, the combination of static injection timing 26o BTDC and injector opening pressure of 230 bar was found effective in reducing NOx levels with no significant drop in performance. Advancing the injection timing to 29° BTDC with 230 bar injector opening pressure resulted in marginal increase in performance and reduction in Smoke levels by 0.4 Bosch Smoke Unit Number (BSN). NOx emissions were slightly higher than that of baseline. Drop in brake thermal efficiency and increase in smoke emission levels observed for the injector located nearer to intake valve. Performance and smoke levels are inferior to that of conventional baseline reading even after the injection timing advance. Increase of smoke by 1.6 Bosch Smoke Number (BSN) is observed at full load for the injection timing of 29° BTDC. Significant increase in Hydrocarbon and Carbon Monoxide emissions were also observed. In general it is observed that the injector location nearer to the exhaust valve has a very good potential for reducing Oxides of Nitrogen emissions without affecting the performance.

The purpose of this paper is to investigate the effectiveness of marketing mix strategies used by travel agencies in Mauritius during off peak seasons, in order to determine how to stimulate demand for international travel services and thus maximise the organisation’s revenue. This study explores the impact of off peak season on marketing mix strategies of travel agencies in Mauritius. The researcher adopted a quantitative research method. The target population comprised of 91 licensed travel agencies in Mauritius and the factor analysis carried out in the survey enabled the identification of latent factors that could affect the performance of travel agencies. The results of the findings led to the development of a marketing framework that travel agencies could consider in order to maximize their profitability during low seasons.

In this paper we present a slightly modified Binary Inversion Algorithm (BIA) to speed up scalar point multiplication of National Institute of Standards and Technology (NIST) recommended elliptic curve with moduli 2521 -1. The effectiveness of the above method is mathematically analyzed by using statistical analysis and by computing series of scalar point multiplications Q= k.P for randomly generated k. Our method uses 2 random generators for generating ‘k’ namely, Random number generator based on Elliptic Curve Operations and Blum-Blum-Shub Generator. The mathematical analysis shows that above technique speeds up the inversion operation and consequently the scalar point multiplication of the above NIST recommended curve. New architecture based on the modified BIA is proposed. The results show that the modified BIA can be implemented in the hardware to speed up the scalar point multiplication.

TiO₂ and TiO₂-SiO₂ nanocomposite was synthesized by sol-gel method at room temperature using titanium tetraisopropoxide with ethanol and water mixture as Titania source and Silicic acid as Silica source. Characterization of the product was carried out by means of X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometry (EDS), Transmission Electron Microscopy (TEM) and Fourier Transform Infrared (FT-IR). An average grain size of ~13nm was obtained for TiO₂ and ~2nm for TiO₂-SiO₂, as estimated by the Debye-Scherrer’s equation. From the FTIR results, peaks were observed at 3408 cm^-1 and 1627 cm^-1 in both samples due to stretching and bending vibrations of -OH groups.