Correlation for prediction of vapor pressures of pure fluids incorporating renormalization group formulations with corresponding-states principle

A simple correlation for predicting the vapor pressures of coal liquids between the freezing and critical points, and extending to normal fluids, has been developed on the basis of renormalization group theory and phenomenological scaling theory. The Clapeyron equation has been reduced to the integral form

to represent vapor pressure using a generalized correlation developed by Sivaraman et al. (1983) for the prediction of latent heats of vaporization of normal fluids and coal-liquid model compounds. L*, the dimensionless latent heat of vaporization, andΔz, the difference between the compressibility factors of the saturated vapor and liquid, are given by the corresponding-states correlations

and

based on the formulations of Pitzer et al. (1955). A simple expression for the latent heat of vaporization developed by Torquato and Stell (1982) is incorporated into this correlation. The vapor-pressure correlation has been tested successfully for 23 pure-component systems including aromatic and heterocyclic compounds often found in coal liquids and shale oil in the region 0 〈 ε = (T_c-T)/T_c 〈 0.69. The deviations in the predicted vapor pressures are in the range 0.11–5.45%.     

Investigation on the radiolytic stability of polybenzimidazole-based polymeric resins for the recovery of lanthanides,actinides, palladium from aqueous medium

Journal of Radioanalytical and Nuclear Chemistry - Radiolytic stability of polymeric resins is an important aspects in nuclear materials processing. The different dosage of gamma radiation was...     

The graphs that have antivoltages using groups of small order

Given a group $\Gamma$ of order at most six, we characterize the graphs that have $\Gamma$-antivoltages and also determine the list of minor-minimal graphs that have no $\Gamma$-antivoltage. Our characterizations yield polynomial-time recognition algorithms for such graphs.     

Skeletal diversity through radical cyclization of tetrahydropyridine scaffolds

Suitably functionalized tetrahydropyridines (methyl pipecolates) have been used as conformationally biased templates for radical cyclizations to access benzoisoquinuclidines and linearly fused indenopiperidines. Variation of skeletal types is determined by location of a radical-initiating element.     

Analysis of DNA relaxation and cleavage activities of recombinant Mycobacterium tuberculosis DNA topoisomerase I from a new expression and purification protocol

Background  

Mycobacterium tuberculosis DNA topoisomerase I is an attractive target for discovery of novel TB drugs that act by enhancing the accumulation of the topoisomerase-DNA cleavage product. It shares a common transesterification domain with other type IA DNA topoisomerases. There is, however, no homology between the C-terminal DNA binding domains of Escherichia coli and M. tuberculosis DNA topoisomerase I proteins.     

High temperature all solid state supercapacitor based on multi-walled carbon nanotubes and poly[2,5 benzimidazole]

Supercapacitor containing multi-walled carbon nanotubes (MWCNT) as the electrode material and phosphoric acid-doped poly[2,5 benzimidazole] (ABPBI) as the solid electrolyte and separator membrane has been investigated in a wide temperature range. Supercapacitors with different solid electrolyte concentrations have been fabricated and evaluated for their electrochemical performance. Specific capacitance of supercapacitors at room temperature was found to increase after the first heating cycle. Supercapacitor containing 10?wt.% of solid electrolyte in the electrode shows higher specific capacitance than the supercapacitor with liquid electrolyte. Cyclic voltammetry analysis of supercapacitors indicates high rate capability. The linear increase in the specific capacitance with temperature implies that capacitance is predominantly due to electric double layer. Electrochemical impedance analysis indicates that the mass capacitance and Warburg parameter increase with temperature, while solution resistance and leakage resistance decrease with temperature. The complex capacitance of the supercapacitors shows that both real and loss capacitances increase with temperature. The phase angle of supercapacitors is found to be around 85.2?±?1° at room temperature and it decreases with temperature. Galvanostatic charge–discharge cycling exhibits almost constant specific capacitance of 28?F?g^?1 at room temperature. However, it increases sharply and then attains stable value of 52?F?g^?1 during cycling at 100?°C. The increase in specific capacitance has been attributed to increase in surface area of the carbon nanotube (CNT), due to activation by phosphoric acid and diffusion of free phosphoric acid into the central canal of MWCNT.     

QSPR modeling for solubility of fullerene (C(60)) in organic solvents

Solubility of fullerene C(60) in 75 organic solvents was examined to develop quantitative structure-solubility relationships. Topological indices and polarizability parameter computed from refractive index were used to form the regression models. The models suggested for individual data sets such as alkanes, alkyl halides, alcohols, cycloalkanes, alkylbenzenes, and aryl halides have good predictive ability and are better than the models for the combined groups. Inclusion of an indicator parameter which is a combination of atom contributions and contributions of substituents' position in benzenes improved the predictive ability significantly.     

Bithiophene triarylborane dyad: An efficient material for the selective detection of CN− and F− ions

A new fluorescent chemosensor based on bithiophene coupled dimesitylborane (BMB-1) was synthesized and characterized. BMB-1 was used for colorimetric and turn-on fluorescent sensing of cyanide (CN⁻) and fluoride (F⁻) ions, in the presence of other competitive anions in an aqueous (CH₃CN–H₂O) medium. BMB-1 showed a hypsochromic shift (blue shift) with addition of CN⁻ and F⁻ ions in absorption studies. The lower detection level of CN⁻ and F⁻ ions is 1.37 × 10⁻⁹ and 1.75 × 10⁻⁹ M, respectively. The BMB-1 binding mechanism is based on the nucleophilic addition of CN⁻ and F⁻ ions in the internal charge transfer transition of bithio moiety to the boranylmesitylene unit, and the color changes were observed under UV light. This result is further confirmed by Fourier transform infrared spectroscopy, mass spectrometry and density functional theory calculations. Also, the BMB-1 probe is found to be a good adsorbent for the removal of F⁻ ions in real water samples using the adsorption technique.