Selective oxidation of olefins and aromatic alcohols with tert‐butylhydroperoxide catalyzed by polymer‐anchored transition‐metal complexes

Three polymer‐anchored metal complexes (Co, Cu, and Pd) were synthesized and characterized. The catalytic performance of these complexes was tested for the oxidation of olefins and aromatic alcohols. These complexes showed excellent catalytic activity and high selectivity. These complexes selectively gave epoxides and aldehydes from olefins and alcohols, respectively. Individually, the effect of various solvents, oxidants, substrate oxidant molar ratios, temperatures, and catalyst amounts for the oxidation of cyclohexene and benzyl alcohol were studied. Under optimized reaction conditions, 96, 81, and 71% conversions of cyclohexene and 86, 79, and 73% conversions of benzyl alcohol were obtained with Co(II), Cu(II), and Pd(II) catalysts, respectively. The catalytic results reveal that these complexes could be recycled more than five times without much loss in activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Separation of acid–water mixtures by pervaporation using nanoparticle filled mixed matrix copolymer membranes

BACKGROUND: Low energy and less expensive membrane based separation of acetic acid‐water mixtures would be a better alternative to conventional separation processes. However, suitable acid resistant membranes are still lacking. Thus, the objective of the present study was to develop mixed matrix membrane (MMM) which would allow high flux and water selectivity over a wide range of feed concentrations of acid in water. RESULTS: Three MMMs, namely PANBA0.5, PANBA1.5 and PANBA3 were made by emulsion copolymerization of acrylonitrile (AN) and butyl acrylate (BA) with 5.5:1 comonomer ratio and in situ incorporation of 0.5, 1.5 and 3 wt%, sodium montmorilonite (Na‐MMT) nanofillers, respectively. For a feed concentration of 99.5 wt% of acid in water the membranes show good permeation flux (2.61, 3.19, 3.97 kg m^?2 h^?1 µm^?1, for PANBA0.5, PANBA1.5 and PANBA3 membrane, respectively) and very high separation factors for water (1473, 1370, 1292 for PANBA0.5, PANBA1.5 and PANBA3 membrane, respectively) at 30 °C. Similarly for a dilute acid–water solution, i.e. for 71.6 wt% acid the membrane showed a very high thickness normalize flux (8.67, 9.44, 11.56 kg m^?2 h^?1 µm^?1, for PANBA0.5, PANBA1.5 and PANBA3 membrane, respectively) and good water selectivity (101.7, 95.3, 79 for PANBA0.5, PANBA1.5 and PANBA3 membrane, respectively) at the same feed temperature. The permeation ratio, permeability, diffusion coefficient and activation energy for permeation of the membranes were also estimated. CONCLUSION: Unlike most of the reported membranes, the present MMMs allowed high flux and selectivity over a wide range of feed concentrations. These membranes may also be effective for separating other similar organic‐water mixtures. Copyright © 2012 Society of Chemical Industry     

Impact of Climate Change on Future Flood Susceptibility: an Evaluation Based on Deep Learning Algorithms and GCM Model

Floods are common and recurring natural hazards which damages is the destruction for society. Several regions of the world with different climatic conditions face the challenge of floods in different magnitudes. Here we estimate flood susceptibility based on Analytical neural network (ANN), Deep learning neural network (DLNN) and Deep boost (DB) algorithm approach. We also attempt to estimate the future rainfall scenario, using the General circulation model (GCM) with its ensemble. The Representative concentration pathway (RCP) scenario is employed for estimating the future rainfall in more an authentic way. The validation of all models was done with considering different indices and the results show that the DB model is most optimal as compared to the other models. According to the DB model, the spatial coverage of very low, low, moderate, high and very high flood prone region is 68.20%, 9.48%, 5.64%, 7.34% and 9.33% respectively. The approach and results in this research would be beneficial to take the decision in managing this natural hazard in a more efficient way.

     

Recovery of pyridine from water by pervaporation using filled and crosslinked EPDM membranes

Organoselective membrane was prepared from ethylene propylene diene monomer (EPDM) rubber. Crosslinked EPDM rubber was filled with 2, 4 and 6 wt% N330 carbon black filler to produce three different filled membranes designated as EPDMCV2, EPDMCV4 and EPDMCV6, respectively. These filled rubber membranes were used for pervaporative recovery of low concentration of pyridine from water. These filled membranes were characterized by crosslink density, SEM, XRD and mechanical properties. Sorption thermodynamics were discussed. Partial permeability, intrinsic membrane selectivity and diffusion coefficients of solvents were also determined. The filled membranes showed much higher pyridine selectivity than most of the membranes reported for similar system.     

Hedgehog Antagonist Pyrimidine–Indole Hybrid Molecule Inhibits Ciliogenesis through Microtubule Destabilisation

One of the crucial regulators of embryonic patterning and tissue development is the Hedgehog‐glioma (Hh‐Gli) signalling pathway; its uncontrolled activation has been implicated in different types of cancer in adult tissues. Primary cilium is one of the important factors required for the activation of Hh signalling, as it brings the critical components together for key protein–protein interactions required for Hh pathway regulation. Most of the synthetic and natural small molecule modulators of the pathway primarily antagonise Smoothened (Smo) or other effectors like Hh ligand or Gli. Here, we report a previously described Hh antagonist, with a pyrimidine–indole hybrid (PIH) core structure, as an inhibitor of ciliogenesis. The compound is unique in its mode of action, as it shows perturbation of microtubule dynamics in both cell‐based assays and in vivo systems (zebrafish embryos). Further studies revealed that the probable targets are α‐tubulin and its acetylated form, found in the cytoplasm and primary cilia. PIH also showed axonal defasiculation in developing zebrafish embryos. We thus propose that PIH antagonises Hh signalling by repressing cilia biogenesis and disassembling α‐tubulin from its stabilised form.     

Robust vectorization method for electrical circuit drawings using component morphology

Pattern Analysis and Applications - Decomposition and representation of electrical circuit drawings to a suitable vector form has widespread applications related to data compression, storage,...