An efficient sonochemical oxidation of benzyl alcohols into benzaldehydes by FeCl3/HNO3 in acetone

Sonochemical oxidation of benzyl alcohols into corresponding aldehydes by FeCl(3)/HNO(3) in acetone at room temperature has been reported. All substrates give good yield of the products within 10-25 min. The reaction of selected substrates were also studied under reflux and at the room temperature. Further, various Lewis acids were used to evaluate their catalytic efficacy.     

233Pa(2nth, f ) cross-section determination using a fission track technique

The νp process is a primary nucleosynthesis process which occurs in core-collapse supernovae. An essential role in this process is being played by electron antineutrinos. They generate, by absorption on protons, a supply of neutrons which, by (n, p) reactions, allow to overcome waiting point nuclei with rather long beta-decay and proton-capture lifetimes. The synthesis of heavy elements by the νp process depends sensitively on the $\bar \nu _e$ luminosity and spectrum. As has been shown recently, the latter are affected by collective neutrino flavor oscillations which can swap the $\bar \nu _e$ and $\bar \nu _{\mu ,\tau }$ spectra above a certain split energy. Assuming such a swap scenario, we have studied the impact of collective neutrino flavor oscillations on the νp-process nucleosynthesis. Our results show that the production of light p-nuclei up to mass number A = 108 is very sensitive to collective neutrino oscillations.     

Study of the K shell photoelectric parameters of Dy,Yb and W atoms using low energy bremsstrahlung radiation

Low energy external bremsstrahlung (EB) photons were used to estimate the K shell photoelectric parameters; the K shell photoelectric cross section at the K edge, the K shell binding energy, the K shell jump ratio, the K shell jump factors, the Davisson-Kirchner ratio and the K shell oscillator strength for dysprosium (Dy), ytterbium (Yb) and tungsten (W) atoms. The EB photons are produced in the nickel (Ni) target by using the beta particles from a weak beta source of ⁹⁰Sr–⁹⁰Y. These photons are made to fall on these elemental targets of our interest and the transmitted spectrum is measured using GMX 10P HPGe detector coupled to an 8K multichannel analyzer. The sharp decrease at the K edge in the measured spectrum is used to determine the K shell photoelectric parameters of these elements. The experimental results are in good agreement with the theoretical values.     

Models of information aggregation in financial markets: a review

This article reviews static and dynamic models of information aggregation in the literature. It highlights the key assumptions these models make, the results they obtain and the issues that still need to be explored to further our understanding of information aggregation in financial markets.     

Analogue of Aharonov-Bohm effect in spin gauge theory

We predict the possibility of observing analogue of the Aharonov-Bohm effect due to long range interaction between spins originating in the framework of spin gauge theory developed earlier. The effect is predicted for both electrons (fermions) and photons. Appropriate experimental set-ups are suggested.     

Separation of rare earths by reverse phase partition chromatography

Journal of Radioanalytical and Nuclear Chemistry - Individual separation of rare earth isotopes from lanthanum to lutetium has been carried out using reverse phase partition chromatography and...     

Effect of energy dependence of primary beam divergence on the X-ray standing wave characterization of layered materials.

Incident primary beam divergence is a source of systematic error in X-ray standing wave (XSW) characterization of single and multilayer thin films. Primary beam divergence significantly alters the XSW profile of a layered material and can lead to large errors when used with higher excitation energies. The present study suggests that when one uses Mo-Kalpha excitation, the primary beam divergence should be in range of 0.005(0). On the other hand, in the case of Cu-Kalpha excitation, primary beam divergence can be relaxed up to 0.01(0).     

Strong enhancement and extinction of single harmonic intensity in the mid- and end-plateau regions of the high harmonics generated in weakly excited laser plasmas

Strong intensity enhancement or extinction of some single harmonics is observed in high-harmonic generation from 48 fs Ti:sapphire laser pulses propagating through preformed low-excited laser-produced plasmas of various materials (GaAs, Cr, InSb, stainless steel). The intensities of some of the harmonics in the mid- and end-plateau regions vary from ~23-fold enhancement to near disappearance compared with those of the neighboring ones. It is also shown that the observed intensity enhancement (or extinction) can be varied by controlling the chirp of the driving laser radiation.     

Computational method for phase space transport with applications to lobe dynamics and rate of escape

Lobe dynamics and escape from a potential well are general frameworks introduced to study phase space transport in chaotic dynamical systems.While the former approach studies how regions of phase space get transported by reducing the flow to a two-dimensional map, the latter approach studies the phase space structures that lead to critical events by crossing certain barriers. Lobe dynamics describes global transport in terms of lobes, parcels of phase space bounded by stable and unstable invariant manifolds associated to hyperbolic fixed points of the system. Escape from a potential well describes how the critical events occur and quantifies the rate of escape using the flux across the barriers. Both of these frameworks require computation of curves, intersection points, and the area bounded by the curves. We present a theory for classification of intersection points to compute the area bounded between the segments of the curves. This involves the partition of the intersection points into equivalence classes to apply the discrete form of Green’s theorem. We present numerical implementation of the theory, and an alternate method for curves with nontransverse intersections is also presented along with a method to insert points in the curve for densification.     

o-Iodoxy Benzoic Acid–Mediated Synthesis of 3,5-Diarylisoxazoles and Isoxazole-3-carboxylic Acids

A new, convenient, ecofriendly synthesis of 3,5-diarylisoxazoles is reported from α,β-unsaturated ketoximes. Similarly, a novel synthesis of isoxazole carboxylic acids is also reported. Both the methods use efficient, environmentally friendly, and nontoxic iodoxybenzoic acid (IBX) as an oxidative cyclizing reagent. Easy procedure, environmentally benign reaction conditions, and nontoxicity are advantages to the methodology.