Absorption of oxygen by 2-ethylhexaldehyde

The kinetics of absorption of oxygen by 2-ethylhexaldehyde dissolved in 2-ethylhexanoic acid at concentrations up to 1.38 × 10^?3 mole/cm³ (20 wt.-%), in the presence of manganese acetate, was studied in a stirred cell and in bubble and packed bubble columns. Diffusion of oxygen was found to play a major role. The reaction was first order in oxygen and second order with respect to the aldehyde, and the overall third-order rate constant was found to be 2.98 × 10⁷ cm⁶ mole^?2 sec^?1 at 30°. The effect of cobaltous acetate on the specific rate of absorption of oxygen was also studied and manganese acetate was found to be the better catalyst.     

Fertility Inhibitor Heterobimetallic Complexes of Platinum(II) and Palladium(II): Synthetic, Spectroscopic and Antimicrobial Aspects

Synthetic, spectroscopic and antimicrobial aspects of some fertility inhibitor heterobimetallic complexes have been carried out. These heterobimetallic chelates [M(C(5)H(5)N(3))(2)M(2)'(R)(4)]Cl(2) (M = Pd or Pt and M' = Si, Sn, Ti and Zr) have been successfully synthesinzed via the reaction of M(C(5)H(7)N(3))(2)Cl(2) with group four or fourteen dichlorides in 1:2 stoichiometric proportions. The products were characterized by elemental analyses, molecular weight determinations, magnetic susceptibility measurements, conductance, and IR multinuclear NMR and electronic spectral studies. A square planar geometry has been suggested for all the complexes with the help of spectral data. Conductivity data strongly suggest that chlorine atoms are ionic in nature due to which complexes behave as electrolytes. All the complexes have been evaluated for their antmicrobial effects on different species of pathogenic fungi and bacteria. The testicular sperm density, testicular sperm morphology, sperm motility, density of cauda epididymal spermatozoa and fertility in mating trails and biochemical parameters of reproductive organs have been examined and discussed.     

12-tungstophosphoric and 12-tungstosilicicacid supported onto hydrous zirconia for liquid phase tert-butylation of m-cresol

Supported 12-tungstophosphoricacid (12-TPA) and 12-tunstosilicicacid (12-TSA) were used as heterogeneous catalysts for liquid-phase tert-butylation of m-cresol, an industrial important reaction. Alkylation reactions have been carried out with supported 12-TPA by varying different parameters such as % loading of 12-tungstophosphoricacid onto support, mole ratio of alcohol to m-cresol, reaction temperature, amount of the catalyst, reaction time and calcination temperature to optimize the conditions. To see the effect of the acidity on the reaction, the same reaction was studied over supported 12-TSA. Both the catalysts give 100% selectivity for o-isomer with different % conversion. The difference in catalyst performance of both the catalyst was correlated with the value of total acidity as well as Bronsted acidity.     

EGIS'92

Announcement

EGIS'92 Third European Conference on Geographical Information Systems at the Park Hilton in Munich Germany, March 23–26, 1992     

Survey of denoising,segmentation and classification of magnetic resonance imaging for prostate cancer

Multimedia Tools and Applications - Prostate cancer (PCa) has become the second most dreadful cancer in men after lung cancer. Traditional approaches used for treatment of PCa were manual, time...     

Mechanical,electrical, and thermal expansion properties of carbon nanotube-based silver and silver-palladium alloy composites

The mechanical, electrical, and thermal expansion properties of carbon nanotube（CNT）-based silver and silver–palladium（10：1, w/w） alloy nanocomposites are reported. To tailor the properties of silver, CNTs were incorporated into a silver matrix by a modified molecular level-mixing process. CNTs interact weakly with silver because of their non-reactive nature and lack of mutual solubility. Therefore, palladium was utilized as an alloying element to improve interfacial adhesion. Comparative microstructural characterizations and property evaluations of the nanocomposites were performed. The structural characterizations revealed that decorated type-CNTs were dispersed, embedded, and anchored into the silver matrix. The experimental results indicated that the modification of the silver and silver–palladium nanocomposite with CNT resulted in increases in the hardness and Young＇s modulus along with concomitant decreases in the electrical conductivity and the coefficient of thermal expansion（CTE）. The hardness and Young＇s modulus of the nanocomposites were increased by 30%？40% whereas the CTE was decreased to 50%-60% of the CTE of silver. The significantly improved CTE and the mechanical properties of the CNT-reinforced silver and silver–palladium nanocomposites are correlated with the intriguing properties of CNTs and with good interfacial adhesion between the CNTs and silver as a result of the fabrication process and the contact action of palladium as an alloying element.     

Piezo/pyro/photo-catalysis activities in Ba0.85Ca0.15(Ti0.9Zr0.1)1-xFexO3 ceramics

Ba_0.85Ca_0.15(Ti_0.9Zr_0.1)_1-xFe_xO₃ (x = 0, 0.5, and 1%) ceramics were studied for piezocatalysis, photocatalysis, and pyrocatalysis using dye degradation in the simulated wastewater. The effect of electrical poling was also performed and found a significant impact of poling on all three catalytic reactions. Fe decreased the optical bandgap of Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃ (BCZTO) to the visible region. Bandgap for x = 0, 0.005, and 0.01 was found to be 3.14 eV, 2.75 eV, and 2.61 eV, respectively. Interestingly, visible light photocatalytic activity was observed after Fe inclusion in BCZTO lattice. These compositions have also demonstrated dye degradation under ultrasonication (piezocatalytsis) and during temporal temperature change (pyrocatalysis). Results indicate promising multicatalysis in BCZTO ceramics which can be tuned using Fe substitution.     

Effect of poling on piezocatalytic removal of muti-pollutants using BaTiO3

The BaTiO₃ powder was prepared via a solid-state reaction route. It was studied for the degradation of bacterial cells, dye, and pharmaceuticals waste using ultrasonically driven piezocatalytic effect. The bacterial catalytic behavior of poled BaTiO₃ was remarkably increased during ultrasonication (10% E coli survival in 60 minutes). The structural damages were illustrated using scanning electron micrographs of bacterial cells which demonstrated morphological manifestations under different conditions. Methylene blue (MB dye), ciprofloxacin and diclofenac were also cleaned using the piezocatalytic effect associated with the poled BaTiO₃ powder. Around 92, 85, and 78% of degradations were observed within 150 minutes duration for methylene blue, ciprofloxacin, and diclofenac, respectively.     

Iodine-loaded poly(silicic acid) gellan nanocomposite mucoadhesive film for antibacterial application

Iodine-loaded poly(silicic acid) gellan nanocomposite film was fabricated and evaluated for antibacterial properties. Poly(silicic acid) nanoparticles were synthesized by condensation of silicic acid under alkaline conditions in the presence of polyvinyl pyrrolidone, phosphate ions, and molecular iodine. The nanoparticles were incorporated into gellan dispersion to prepare gellan nanocomposite film using the solvent casting method. The nanocomposite films were characterized by Fourier transformed infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction studies. The results of characterization studies indicated improved thermal stability and an increase in the degree of crystallinity. The scanning electron micrographs and energy dispersive X-ray spectrum confirmed the uniform dispersion of silica and iodine in the nanocomposite films. The analysis of physical and mechanical properties revealed the enhanced tensile strength, moisture resistance, and higher folding endurance of poly(silicic acid) gellan nanocomposite films as compared to gellan film. Further, the iodine-loaded poly(silicic acid) gellan nanocomposite films showed good antibacterial activity against Staphylococcus aureus and Escherichia coli and effective mucoadhesive strength. The results indicate that iodine-loaded poly(silicic acid) gellan nanocomposite mucoadhesive film can be used for potential antibacterial applications in pharmaceuticals.     

Microstructure and properties of flame sprayed tungsten carbide coatings

This article reports on feasibility experiments carried out with oxy-acetylene spray system with various oxygen to fuel ratios using two different tungsten carbide powders and powder feeding methods, to evaluate the newly developed fused WC, synthesised by transferred arc thermal plasma method. Transferred arc thermal plasma method is more economical and less energy intensive than the conventional arc method and results in a fused carbide powder with higher hardness. The microstructure and phase composition of powders and coatings were analysed by optical and scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Carbon content of the powders and coatings were determined to study the decarburisation of the material during spraying process. Coatings were also characterised by their hardness and abrasive wear. The effects of metallurgical transformation and phase content are related to wear performance. The results demonstrate that the powders exhibit various degree of phase transformation during the spray process depending on the type of powder, powder feeding and spray parameters. The carbon loss during the spray process in excess of 45% resulted in reduced hardness and wear resistance of the coatings. Coatings with high amount of WC and W₂C along with FeW₃C showed higher wear resistance. Thus, coatings of high wear resistance can be produced using fused tungsten carbide powder with WC and W₂C phases, which can be economically synthesised by thermal plasma transferred arc method.