Evaluation of the aquifer characteristics of the basaltic terrain of Maharashtra in India

The paper attempts to evaluate the permeability data obtained from 75 aquifer performance tests conducted on open wells tapping the water table aquifer of the basaltic lava flows spread over the three different basins of Maharashtra. The permeability has been computed by Thiem’s formula and the modified Theis non-equilibrium formula. The statistical analysis of the permeability data of the study basins,viz., Bhima, Godavari and Wardha, reveal a decrease in permeability range as one proceeds from the Bhima basin (low rainfall area) through the Godavari basin (assured rainfall area) to the high rainfall area of Wardha basin. The permeability frequency graphs of the three study basins reveal different hydrogeological characteristics for each.     

On the solubility of copper and nickel complexes of rapox in organic solvents

The solubilities of copper and nickel complexes of RAPOX were determined in thirteen different organic solvents colorimetrically employing Lumetron 402-E. Both these chelates possessed maximum solubility in cyclohexanone, namely, 1·04 gm. for Cu-RAPOXimate and 1·710 gm. for Ni-RAPOXimate respectively in 100 ml. of the solution.     

Synergic extraction of manganese(II) with thiocyanate and pyridine

Journal of Radioanalytical and Nuclear Chemistry -     

Einstein-Rosen inflationary Universe in general relativity

Einstein-Rosen inflationary Universe is investigated in the presence of massless scalar field with a flat potential. To get an inflationary Universe, we have considered a flat region in which the potential V is constant. Some physical properties of the model are discussed.     

Dirichlet expression for <Emphasis Type="Italic">L</Emphasis>(1, <Emphasis Type="Italic">χ</Emphasis>) with general Dirichlet character

In the famous work of Dirichlet on class number formula, L(s, χ) at s = 1 has been expressed as a finite sum, where L(s, χ) is the Dirichlet L-series of a real Dirichlet character. We show that this expression with obvious modification is valid for the general primitive Dirichlet character χ.     

High-performance liquid chromatography and LC-ESI-MS method for the identification and quantification of two biologically active isomeric coumarinolignoids cleomiscosin A and cleomiscosin B in different extracts of Cleome viscosa

A rapid, sensitive and simple reverse-phase high-performance liquid chromatographic-electrospray ionization-mass spectrometry method for simultaneous determination of cleomiscosin A and cleomiscosin B has been developed and validated. The isomeric coumarinolignoids cleomiscosin A (1) and cleomiscosin B (2) were separated on a Waters symmetry C(18) column with a solvent system composed of acetonitrile-methanol (1:2) and acetic acid-water (0.5:99.5) in a gradient elution mode. The absorption at 326 nm was chosen as the measuring wavelength in which resolution and baseline separation of compounds 1 and 2 could be obtained. The identity of the two isomeric compounds 1 and 2 in the samples were determined on a triple quadrupole mass spectrometer with ESI interface operating in the positive mode. Calibration curves were linear (r(2) > 0.993) over the concentration range 20-200 microg/mL for cleomiscosin A and 10-200 microg/mL for cleomiscosin B with acceptable accuracy and precision, respectively. The intra-day and inter-day precision were 1.13 and 0.82% for cleomiscosin A and 1.78 and 1.28% for cleomiscosin B, respectively. The validated method was successfully applied for the analysis of the above two compounds in different extracts of Cleome viscosa.     

Validated chiral high-performance liquid chromatography method for a novel anti-methicillin-resistant Staphylococcus aureus fluoroquinolone WCK 771

A sensitive, simple, specific, precise, accurate and rugged method for the assay and determination of enantiomeric purity of S-(-)-9-fluoro-6,7-dihydro-8-(4-hydroxypiperidin-1-yl)-5-methyl-1-oxo-1H,5H-benzo[i,j]quinolizine-2-carboxylic acid L-arginine salt tetrahydrate (WCK 771) in bulk drug has been developed. The method is RP-HPLC using endcapped C-18 stationary phase and chiral mobile phase. Chirality to the mobile phase was imparted with addition of beta-cyclodextrin. The UV-vis detector was operated at 290 nm. The flow rate of mobile phase was 2 ml/min. The method offers excellent separation of two enantiomers with resolution more than 2 and tailing factor less than 1.5. The method was validated for the assay of WCK 771 and quantification of R-(+)-enantiomer impurity in bulk drug. The calibration curves showed excellent linearity over the concentration range of 0.05-0.15 mg/ml for WCK 771 and 0.5-7.5 microg/ml for R-(+)-enantiomer. The precision (RSD) of the assay was 0.23%. The limit of detection and limit of quantitation of the method for WCK 771 were 0.015 and 0.06 microg/ml, respectively. The limit of detection and limit of quantitation for R-(+)-enantiomer were 0.025 and 0.09 microg/ml, respectively. The average recovery of the R-(+)-enantiomer was 100.5%. Same method was applied for the assay and determination of enantiomeric purity of WCK 771 in the intravenous formulation.     

Adsorption kinetics of asphaltenes at the oil-water interface and nanoaggregation in the bulk

Asphaltenes constitute high molecular weight constituents of crude oils that are insoluble in n-heptane and soluble in toluene. They contribute to the stabilization of the water-in-oil emulsions formed during crude oil recovery and hinder drop-drop coalescence. As a result, asphaltenes unfavorably impact water-oil separation processes and consequently oil production rates. In view of this there is a need to better understand the physicochemical effects of asphaltenes at water-oil interfaces. This study elucidates aspects of these effects based on new data on the interfacial tension in such systems from pendant drop experiments, supported by results from nuclear magnetic resonance (NMR) and dynamic light scattering (DLS) studies. The pendant drop experiments using different asphaltene concentrations (mass fractions) and solvent viscosities indicate that the interfacial tension reduction kinetics at short times are controlled by bulk diffusion of the fraction of asphaltenes present as monomer. At low mass fractions much of the asphaltenes appear to be present as monomers, but at mass fractions greater than about 80 ppm they appear to aggregate into larger structures, a finding consistent with the NMR and DLS results. At longer times interfacial tension reduction kinetics are slower and no longer diffusion controlled. To investigate the controlling mechanisms at this later stage the pendant drop experiment was made to function in a fashion similar to a Langmuir trough with interfacial tension being measured during expansion of a droplet aged in various conditions. The interfacial tension was observed to depend on surface coverage and not on time. All observations indicate the later stage transition is to an adsorption barrier-controlled regime rather than to a conformational relaxation regime.