Room Temperature Palladium‐Catalyzed Decarboxylative Acyl/Aroylation using [Fe(III)(EDTA)(η2‐O2)]3− as Oxidant at Biological pH

The purple‐coloured iron peroxo complex [Fe(III)EDTA(η²‐O₂)]³⁻ as a novel reagent system for Pd‐catalyzed decarboxylative ortho‐acylation of acetanilides with α‐oxocarboxylic acids at room temperature in aqueous media has been realized. This reaction provides an effective access to ortho‐acylacetanilides under mild conditions.     

Technology Status of Particulate Removal from High-Temperature High-Pressure Combustion Gases

The adoption of coal-fired pressurized fluidized-bed combined-cycle combustion systems by utilities for electric power generation depends to a large extent on the development of an efficient and economic cleanup system between the combustor and gas turbine. To accomplish particulate removal from a dust-laden gas stream, a number of separation devices have been developed. These include conventional and augmented cyclones; porous metal, fabric, and ceramic membrane filters; fixed-, continuously moving-, and fluidized-bed granular filters; electrostatic precipitators; as well as several other novel separation devices. The results of tests of these devices are discussed in relation to pressurized fluidized-bed combustion applications.     

Peculiar feature of KCl + SbCl3 phosphors: PL and XRD studies

Photoluminescence of antimony-activated potassium chloride prepared by a mechanical grinding method has been reported. The non-coincidence of the excitation and diffuse absorption band has been found as a result of the peculiar nature of the mixed phosphor, which suggests the different nature of the luminescent centers present in the phosphor. This difference in the nature of the diffuse absorption spectra and excitation spectra has been attributed to the Sb³⁺ and Sb⁵⁺ ions in the KCl+SbCl₃ host lattice. Photoluminescence intensity has been strongly enhanced by reducing the temperature to the liquid nitrogen temperature. The powder diffraction pattern obtained from the XRD analysis shows the presence of complexes over the surface.     

Framework for flexibility in dynamic supply chain management

Effective Supply Chain Management (SCM) is a pivotal issue in the dynamically changing business environment. Dynamic SCM requires integrated decision-making amongst autonomous chain partners with effective decision information synchronization amongst them. By exploiting flexibility in supply chain structures, better performance can be achieved. Similarly, by judiciously employing decision flexibility and the associated dynamic control amongst autonomous supply chain nodes, many improvements are possible. The paper presents a study on the role of different flexibility options (i.e. no flexibility, partial flexibility and full flexibility) in a dynamic supply chain model based on some key parameters and performance measures. Supply chain flexibility has significant potential and needs a greater research attention. The paper attempts to advance the knowledge of dynamic control on effective flexibility exploitation in the context of dynamic supply chains. A simulation model of a dynamic supply chain is used for this purpose. The key results are highlighted along with industry implications. Here each supply chain node involves decision-making. Based on the order and sample information available from the immediate buyers or customers, the supplier selection decisions are dynamically made. A seemingly good decision at a stage based on local information often ends up as detrimental not only to the total chain cost, but also to the total costs of the node itself. These observations are important for the designers and managers of the flexible supply chain systems to arrive at appropriate types and a judicious level of flexibility to attain significant improvements in total cost reduction. The modelling of dynamic supply chains with a focus on flexibility can offer enormous potential to the industry. This paper addresses this interesting and challenging domain.     

Studies on textural properties of lanthanum-exchanged Y zeolites as promising materials for value upgradation of Jatropha oil

A series of La (Lanthanum)-exchanged Y zeolites have been prepared and the changes occurred in textural properties of the material have been characterized by XRD, SEM, surface area, pore volume, and pore size distribution techniques. La loading was observed to enhance not only acidity but also the porosity (in terms of mesopores) of the Y zeolite. The parent HY and three La loaded samples (LaHY-1, LaHY-2, and LaHY-3) have been studied for the changes in properties occurred by La loading and their collective influence on the catalytic performance toward the Jatropha oil to gasoline (JTG) reaction. All the catalysts exhibited 100 % conversion but the performance toward the gasoline selectivity is increased in the order of HY < LaHY-3 < LaHY-1 < LaHY-2. Detailed analysis of the results indicated that the increase in porosity (both in micro- and meso-pore region) rather than the acidity is responsible for enhanced catalytic performance of the LaHY-2 catalyst. This particular catalyst also exhibited lower coke formation and prolonged time-on-stream stability in the JTG reaction ascribed to the facile diffusion of the product molecules facilitated in mesopores.     

Structural,optical and electrical properties of CdZnS thin films

The thin films of Cd_1-x Zn _x S (x?=?0, 0.2, 0.4, 0.6, 0.8 and 1) have been prepared by the vacuum evaporation method using a mechanically alloyed mixture of CdS and ZnS. The structural, optical and electrical properties have been investigated through the X-ray diffractometer, spectrophotometer and Keithley electrometer. The X-ray diffraction patterns of these films show that films are polycrystalline in nature having preferential orientation along the (002) plane. In the absorption spectra of these films, absorption edge shifts towards lower wavelength with the increase of Zn concentration. The energy band gap has been determined using these spectra. It is found that the energy band gap increases with increasing Zn concentration. The electrical conductivity of so prepared thin films has been determined using a I–V characteristic curve for these films. The result indicates that the electrical conductivity decreases with increasing Zn content and increases with temperature. An effort has also been made to obtain activation energy of these films which increases with increasing Zn concentration in CdS.     

Preparation and characterization of exfoliated layered double hydroxide/silicone rubber nanocomposites

Silicone rubber (SR)/Mg–Al layered double hydroxide (LDH) nanocomposites were prepared by the solution intercalation of SR crosslinked by a platinum‐catalyzed hydrosilylation reaction into the galleries of dodecyl sulfate intercalated layered double hydroxide (DS–LDH). X‐ray diffraction and transmission electron microscopy analysis showed the formation of exfoliated structures of organomodified LDH layers in the SR matrix. The tensile strength and elongation at break of SR/DS–LDH (5 wt %) were maximally improved by 53 and 38%, respectively, in comparison with those of the neat polymer. Thermogravimetric analysis indicated that the thermal degradation temperature of the exfoliated SR/DS–LDH (1 wt %) nanocomposites at 50% weight loss was 20°C higher than that of pure SR. Differential scanning calorimetry analysis data confirmed that the melting temperature of the nanocomposites increased at lower filler loadings (1, 3, and 5 wt %), whereas it decreased at a higher filler loading (8 wt %). The relative improvements in the solvent‐uptake resistance behavior of the SR/DS–LDH nanocomposites were also observed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Revelation of graphene-Au for direct write deposition and characterization

Graphene nanosheets were prepared using a modified Hummer''s method, and Au-graphene nanocomposites were fabricated by in situ reduction of a gold salt. The as-produced graphene was characterized by X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy (HR-TEM). In particular, the HR-TEM demonstrated the layered crystallites of graphene with fringe spacing of about 0.32 nm in individual sheets and the ultrafine facetted structure of about 20 to 50 nm of Au particles in graphene composite. Scanning helium ion microscopy (HIM) technique was employed to demonstrate direct write deposition on graphene by lettering with gaps down to 7 nm within the chamber of the microscope. Bare graphene and graphene-gold nanocomposites were further characterized in terms of their composition and optical and electrical properties.     

Towards electrochromic stability in sol–gel-derived tungsten oxide films: cyclic voltammetric and spectrophotometric investigations

Hitherto unexplored irreversible changes during initial coloration/bleaching cycles for sol–gel-derived tungsten oxide (WO₃) films have been investigated using cyclic voltammetric and spectrophotometric techniques. Non-ideal features appearing in the initial five anodic (deintercalation) cycles in the voltammogram with simultaneous decreased optical transmission of the bleached films have been explained in terms of possible stoichiometric variations affecting the coloration efficiency (CE) of the films and the associated mechanisms. Electrochromic stability attained thereafter manifests in retraceable voltammograms and almost invariant value of the CE.     

Biological monitoring of environmental contaminants: Chlorinated hydrocarbons in eggs of hens

High concentrations of persistent chlorinated hydrocarbon pesticide residues were detected by gas-liquid chromatography with an electron capture detector (³H), in eggs of hens collected from Lucknow under the pesticide monitoring programme. The present study reveals extremely high contamination of eggs, particularly with DDT and HCH residues. The eggs may be an important source of DDT and HCH build-up in the human body. Residue levels of p,p′-DDT and its metabolites p,p′-DDE and α, β and γ-isomers of HCH were higher in eggs of poultry-farm hens compared to those of domestic hens. Egg yolk contained higher levels compared with egg white, because of the lipophilic nature of pesticides and the high lipid content in the yolk. Average levels of total DDT and HCH residues in the yolk and white in the whole egg of a poultry-farm hen were found to be 18.5 and 4.6 μg respectively, whereas the average levels were 7.4 and 4.1 μg, respectively, in the whole egg of a domestic hen.