Interaction of two parallel plane jets of different velocities

The interaction of two parallel plane jets of different velocities is studied by flow visualization and PIV measurement to examine the influence of velocity ratio on the development ofjets in the initial region. It is found that the parallel plane jets develop toward the high velocity side and the jet width is reduced with a decrease in the jet velocity ratio. Corresponding to the variation of mean velocity field to the velocity ratio, the magnitudes of turbulence intensities, Reynolds stress and static pressure are weakened in the merging region of the jets and their peak locations of the properties are shifted to the high velocity side. These results indicate that the interaction of two parallel jets is weakened with a decrease in the velocity ratio of the jets.     

Synergic Synthesis and Characterization of tert-Butyl 4-[(E)-But-1-en-3-yn-1-yl]-3-{[tert-butyl(dimethyl)silyl]oxy}-1H-indole-1-carboxylate

Russian Journal of Organic Chemistry - tert-Butyl 4-[(E)-but-1-en-3-yn-1-yl]-3-{[tert-butyl(dimethyl)silyl]oxy}-1H-indole-1-carboxylate has been synthesized with a good yield and selectivity...     

Entropy generation analysis of tangent hyperbolic fluid in quadratic Boussinesq approximation using spectral quasi-linearization method

Applied Mathematics and Mechanics - In many industrial applications, heat transfer and tangent hyperbolic fluid flow processes have been garnering increasing attention, owing to their immense...     

Stability indicating RP-HPLC method development and validation for oseltamivir API

The present study describes the development and subsequent validation of a stability indicating reverse-phase HPLC (RP-HPLC) method for the analysis of oseltamivir active pharmaceutical ingredient (API). The proposed RP-HPLC method utilizes Kromasil C(18), 5 microm, 250 mm x 4.6 mm i.d. column (at ambient temperature), gradient run (using acetonitrile and triethylamine as mobile phase), effluent flow rate (1.0 ml/min), and UV detection at 215 nm for analysis of oseltamivir. The described method was linear over the range of 70-130 microg/ml (r(2)=0.999). The precision, ruggedness and robustness values were also within the prescribed limits (<1% for system precision and <2% for other parameters). Oseltamivir was exposed to acidic, basic, oxidative and thermal stress conditions, and the stressed samples were analyzed by the proposed method. Chromatographic peak purity results indicated the absence of co-eluting peaks with the main peak of oseltamivir, which demonstrated the specificity of assay method for estimation of oseltamivir in presence of degradation products. The proposed method can be used for routine analysis of oseltamivir in quality control laboratories.     

A practical synthesis of 5‐(4′‐methylbiphenyl‐2‐yl)‐1H‐tetrazole

Practical synthesis of 5‐(4′‐methylbiphenyl‐2‐yl)‐1H‐tetrazole, key intermediate in several angiotensin II receptor antagonists from 2‐fluorobenzonitrile in excellent yields and very high purity is described.     

When is a hidden variable theory compatible with quantum mechanics?

This paper is devoted to a study of some of the basic conditions which have to be satisfied by a hidden variable theory in order that it can reproduce the quantum mechanical probabilities. Of course one such condition, which emerges from the important theorem of Bell, is that a hidden variable theory has to be non-local. It is shown that a hidden variable theory is also incompatible with the conventional interpretation of mixed states and the mixing operation in quantum theory. It is therefore concluded that, apart from being non-local, a hidden variable theory would also necessarily violate the usual assumption of quantum theory that the density operator provides an adequate characterization of any ensemble of systems, pure or mixed.     

A computational study of bond dissociation enthalpies in haloethenes

Carbon–hydrogen bond dissociation enthalpies (BDEs) were computed for all haloethenes, C₂H_4−nX_n (n=0–3, X=F, Cl, Br, I), at the B3LYP/6-311+G(3df,2p) level using isodesmic reactions. It was found that C–H bond strengths in the monohaloethenes varied substantially, by as much as 18 kJ mol⁻¹, dependent upon the bond's stereochemical position relative to the halogen. BDEs in the dihaloethanes varied in the order CX₂CH–H>(E)-CHXCX–H>(Z)-CHXCX–H. Trends in the computed bond enthalpies were discussed and explained on the basis of relative steric repulsions and hyperconjugative delocalization interactions, as determined from Natural Bond Orbital analysis.     

Splitting of a liquid jet

We demonstrate that a flowing liquid jet can be controllably split into two separate subfilaments through the application of a sufficiently strong tangential stress to the surface of the jet. In contrast, normal stresses can never split a liquid jet. We apply these results to observations of uncontrolled splitting of jets in electric fields. The experimental realization of controllable jet splitting would provide an entirely novel route for producing small polymeric fibers.