Nonequilibrium Phase Transitions in a Driven Sandpile Model

We construct a driven sandpile slope model and study it by numerical simulations in one dimension. The model is specified by a threshold slope \sigma_c\/, a parameter \alpha\/, governing the local current-slope relation (beyond threshold), and $j_{\rm in}$, the mean input current of sand. A nonequilibrium phase diagram is obtained in the \alpha\, -\, j_{\rm in}\/ plane. We find an infinity of phases, characterized by different mean slopes and separated by continuous or first-order boundaries, some of which we obtain analytically. Extensions to two dimensions are discussed.Comment: 11 pages, RevTeX (preprint format), 4 figures available upon requs

Enhancing Synchrony in Chaotic Oscillators by Dynamic Relaying

In a chain of mutually coupled oscillators, the coupling threshold for synchronization between the outermost identical oscillators decreases when a type of impurity (in terms of parameter mismatch) is introduced in the inner oscillator(s). The outer oscillators interact indirectly via dynamic relaying, mediated by the inner oscillator(s). We confirm this enhancing of critical coupling in the chaotic regimes of R\"ossler system in absence of coupling delay and in Mackey-Glass system with delay coupling. The enhancing effect is experimentally verified in electronic circuit of R\"ossler oscillators.Comment: 4 pages, 9 figure

A Dynamic Renormalization Group Study of Active Nematics

We carry out a systematic construction of the coarse-grained dynamical equation of motion for the orientational order parameter for a two-dimensional active nematic, that is a nonequilibrium steady state with uniaxial, apolar orientational order. Using the dynamical renormalization group, we show that the leading nonlinearities in this equation are marginally \textit{irrelevant}. We discover a special limit of parameters in which the equation of motion for the angle field of bears a close relation to the 2d stochastic Burgers equation. We find nevertheless that, unlike for the Burgers problem, the nonlinearity is marginally irrelevant even in this special limit, as a result of of a hidden fluctuation-dissipation relation. 2d active nematics therefore have quasi-long-range order, just like their equilibrium counterpartsComment: 31 pages 6 figure

Energy levels of Mg<SUP>26</SUP> from the decay of Al<SUP>26</SUP>

Gamma-rays accompanying the decay of long-lived Al26 have been studied by means of coincidence scintillation spectrometry. A level scheme for Mg26 has been proposed in essential agreement with earlier results

Review of recent results on internal conversion

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Note on 5-levels in even-even nuclei

This article does not have an abstract

Oleophobic and hydro phobic properties of fluoro compounds and their application in leather making

Application of fluoro compounds in leather making is surveyed. The theory behind the oil and water repelling mechanisms of fluoral chemicals is explained. The importance of various types of fluoro chemicals, such as fluoro acrylics, copolymers of fluorine containing monomers, fluoro silicones, phosphorous containing fluoro acrylics is highlighted. Fungicide and disinfectant properties of fluoro compounds on leather are reported. Possible developments and application of these fluoro chemicals in leather making are suggested

Thermal and photochemical reactions of chromium (IV)-diperoxo complexes with organic substrates- evidence for hydroxylation of proline and phenol

The diperoxo complexes of chromium in an unusual oxidation number viz. 4, react with organic substrates such as proline and phenol to give bydroxyproline and o-benzoquinone as products respectively. The organic products were identified by electronic spectra as well as by their characteristic R1 values in thin layer chromatography using n-propanol-water(1:1v/v) mixure and chloroform as solvents for proline and phenol reaction products respectively. the studies reveal that the hydroperoxide radicals formed during the decomposition of Cr(IV)-diperoxo complexes give rise to the hydroxylation processes observed. The hydroxylation reactions are facilitated by light and yields of hydroxyproline upto 9% (from proline) have been obtained . The study presents one of the first examples of the use of Cr(IV) systems for biologically relevant processes such as hydroxylation