Polymerization of acrylamide initiated by peroxomonosulphate and metal ion catalysis

The kinetics of polymerization of acrylamide initiated by potassium peroxomonosulphate, in the presence and absence of Ag⁺, were studied. Rates of polymerization and oxone disappearance were followed. From the rate law for the polymerization, a mechanism has been proposed.     

Surface characterization of WO(3)/ZrO(2) catalysts

A series of WO(3)/ZrO(2) catalysts with tungsten (W) loadings ranging from 0.5 to 11.4 wt% was prepared by incipient wetness impregnation on a preformed ZrO(2) support. The oxidic catalysts were characterized using XRD, Raman spectroscopy, XPS, ISS, and IR spectroscopy. XRD and Raman results showed that the ZrO(2) support was predominantly present in the monoclinic form. XPS and Raman measurements indicated the formation of increasing amounts of W interaction species for catalysts with W loadings up to 8.8 wt% WO(3). In addition to the W interaction species, bulk WO(3) was also observed for catalysts with W loadings > or = 3.0 wt% WO(3). Comparison of the XPS results with coverage measurements by ISS and CO adsorption suggests that the W surface phase is in the form of two-dimensional polymeric patches for catalysts with W loadings 3.0 < or = wt% WO(3) < or = 4.5. For catalysts with W loadings >4.5 wt% WO(3), the results indicated an additional build-up of a bilayer (or multilayer) polymeric W species. Analysis of the hydroxyl region of ZrO(2) by IR spectroscopy showed that initial additions of W occur on the high frequency hydroxyl group. A schematic for the structure of the catalysts has been proposed based on the above observations.     

Iterative computational method for the rapid analysis of iron and plutonium by controlled potential coulometry and some interesting observations on the coulogram of the Pu(III) /Pu(IV/ couple

An iterative computational method for the determination of metal ions in aqueous solutions which form reversible couples such as Fe(II)/Fe(III), Pu(III)/Pu(IV) etc. by controlled potential coulometry has been developed. The method involves carrying out the electrolysis to about 95–97% and calculating the total amount present in the sample by an iterative computational method. The method utilizes the direct application of the Nernst equation. The important criterion to be met is that the coulogram of the couple should strictly obey the Nernst equation. The validity of the method has been checked by analyzing about 50 samples of a standard iron solution. Results of analysis of mixtures of Pu and Fe by the iterative technique show that the interference of Fe can almost entirely be eliminated. However, analysis of Pu samples by this procedure gives results about 2–3% lower than the expected value. A careful examination of the experimental coulograms of Pu in lM HClO₄ indicates a slight deviation from the theoretical coulogram, where as those of Fe match exactly.     

Microwave assisted synthesis of an unusual dinitro phytochemical

A novel dinitro secondary metabolite, 2-nitro-4-(2^′-nitroethenyl)phenol from a marine source, has been prepared via highly accelerated, microwave assisted, nitration reactions using mild reagents. ipso-Substitution of a carboxy group by a nitro group is discussed.     

Nonequilibrium response of a disordered Ising chain

The relaxation behaviour of a model disordered system is studied. The model considered is a nearest neighbour Ising chain in which the bond strengths are distributed at random between the discrete values +J and -J with equal probability. The system is prepared in a given state and is allowed to relax to a new state of equilibrium. This approach to equilibrium is probed by means of an applied, weak, time-dependent magnetic field. The relevant physical quantity is a nonequilibrium susceptibility which is calculated exactly. A comparison between this, and the corresponding quantity for the pure chain, reveals certain distinctive features of the time-dependent properties of disordered systems.Deceased     

Comparative study on heat pipe performance using aqueous solutions of alcohols

This paper deals with the performance characterization of heat pipes using an aqueous solution of long chain alcohols like n-Butanol, n-Pentanol, n-Hexanol and n-Heptanol as working mediums. These solutions are called as self-rewetting fluids, since these fluid mixtures possess a non-linear dependence of the surface tension with temperature. A cylindrical heat pipe made up of copper with two layers of wrapped screen is used as a wick material and partially filled with the self-rewetting fluid water mixture and tested for its heat transport capability like thermal efficiency and thermal resistance at different inclinations and input power levels. A number of tests have been performed with heat pipes, filled with various aqueous solutions of alcohols with a concentration of 2?ml/l in de-ionized water (DI water) on volume basis. The results obtained for heat pipes using self rewetting fluids show improved performances, when compared to DI water heat pipes.     

Novel Separation Processes for Solid/Liquid Separations in Coal Derived Liquids

The removal of the mineral matter found in coal derived liquids is a very difficult solid/liquid separation process. Clays, pyrites and other minerals that occur in coal ultimately find their way into the liquefied product. This is the case, e.g., for both the solvent refined coal (SRC-I) and H-Coal processes. The ash content of bituminous coals which may be fed to coal liquefaction processes normally rangesfrom 6 to 11 wt.%. The ash content of the coal liquid product can range from 4 to 20 wt.% depending upon the lique-faction .process. Ash levels must be reduced to, e.g., 0.4 wt.% in the case of boiler fuel and less than 0.1 wt.% for gas turbine fuels.     

Development of Biosensor for Catechol Using Electrosynthesized Poly(3‐methylthiophene) and Incorporation of LAC Simultaneously

Simultaneous electropolymerization of 3‐methylthiophene and incorporation of Laccase (LAC) was carried out in the presence of propylene carbonate as a medium by amperometric method. This enzyme modified electrode was used for the sensing of polyphenol. Catechol is taken as a model compound for the study. UV‐Vis spectral studies suggest no denaturation of LAC in presence of propylene carbonate. The SEM studies reveal the surface morphology and incorporation of LAC in P3MT with agglomerated flaky masses are observed in with and without enzyme micrographs. The cyclic voltammograms were recorded for 0.01 mM catechol on plain glassy carbon, polymer and enzyme incorporated electrodes at pH 6.0 and scan rate 50 mV s^?1. The fabricated electrochemical biosensor was used for the determination of catechol in aqueous solution by Differential Pulse Voltammetry (DPV) technique. The concentration linear range of 8×10^?8 to 1.4×10^?5 M a value of Michealis? Menten constant K_m=7.67 µmol dm^?3 and activation energy is 32.75 kJ mol^?1. It retains 83 % of the original activity after 60 days which is much higher than that of other biosensors. The developed biosensor was used to quantify catechol in the determination in real samples.