Radiation effects on styrene–butadiene–ethylene–propylene diene monomer‐multiple walled carbon nanotube nanocomposites: vulcanization and characterization

Varying compositions of styrene–butadiene rubber (SBR) and ethylene–propylene diene monomer (EPDM) 50:50 blend containing multiple walled carbon nanotube (MWNT) as nanoparticulate filler (0.5–5%) were prepared and their efficacy for radiation vulcanization was analyzed by gel‐content, Charlesby‐Pinner parameter, and crosslinking density measurements. Radiation sensitivity of the nanocomposites increased with increase in the MWNT fraction and radiation dose in the dose range studied. The elastic modulus, tensile strength increased with the radiation dose, while elongation at break exhibited downward trend. The extent of reinforcement as assessed using Kraus equation suggested high reinforcement of blend on MWNT addition. The reinforcing mechanism of nanocomposites was studied by various micromechanics models which predicted higher modulus than the experimentally observed results, indicating agglomeration in the nanocomposites. The thermal stability of the composites increased with increase in MWNT loading has been attributed to the antioxidancy induced by nanotubes and higher crosslinking extent of the nanocomposites. Copyright © 2010 John Wiley & Sons, Ltd.     

Band head spin assignment of Tl isotopes of superdeformed rotational bands

The Variable Moment of Inertia (VMI) model is proposed for the assignment of band head spin of super deformed (SD) rotational bands, which in turn is helpful in the spin prediction of SD bands. The moment of inertia and stiffness parameter (C), were calculated by fitting the proposed transition energies. The calculated transition energies are highly dependent on the prescribed spins. The calculated and observed transition energies agree well when an accurate band head spin (I ₀) is assigned. The results are in good agreement with other theoretical results reported in literature. In this paper, we have reported the band head spin value 16 rotational band of super deformed Tl isotopes.     

Grafting Vinyl Monomers onto Nylon 6 Fiber. II. Graft Copolymerization of Methyl Methacrylate onto Nylon 6 Fiber by Photoirradiation in the Presence of Fructose

Photopolymerization of methyl methacrylate (MMA) onto nylon 6 fiber by UV radiation in alcoholic solutions of water-methanol, water-ethanol, and water-n-propanol in the presence of fructose was investigated. The effects of monomer concentration, time of polymerization, fructose concentration, and effect of media have also been studied. Graft add-on (GAO) % greatly enhanced with an increase in monomer concentration and time. With fructose concentration it increases up to 15 mmol/L of fructose and thereafter falls. The GAO in the media is in the following order: W + M + F > W + E + F > W + P + F(W = water; M = methanol; E = ethanol; P = n-propanol). A probable mechanism has been suggested. It appears that the active site is formed on MMA which abstracts an H-atom from the nylon 6 backbone, giving rise to graft of MMA by mutual combination.     

Grafting Vinyl Monomers onto Nylon 6 Fiber. III. Graft Copolymerization of Vinyl Monomers onto Nylon 6 Fiber in Water Medium in the Presence of Fructose

Nylon 6 fiber was grafted with various vinyl monomers e.g., methyl methacrylate (MMA), ethyl methacrylate (EMA), and n-butyl methacrylate (n-BMA), in water in the presence of fructose using a carbon arc lamp as the source of photoirradiation at 70°C and a liquor ratio of 1:26. The effects of various parameters, e.g., monomer concentration, time of grafting, and fructose concentration on grafting reactions, were studied individually for each monomer. The graft yield is greatly enhanced by increasing the monomer concentration and the time of grafting. However, the optimum fructose concentration is required for maximum grafting efficiency. The accelerating action of photopolymerization by fructose was attributed to the sensitizing action of fructose involving an energy transfer.     

An efficient approach for the synthesis of spirooxindole derivatives catalyzed by novel sulfated choline based heteropolyanion at room temperature

A new zwitterionic salt, sulfated choline based heteropolyanion, which was reported earlier by our group, has been found to be very effective for the synthesis of spirooxindole derivatives at room temperature. The heteropolyanion based on sulfated ionic liquid (HIL) showed promising features for the reaction, such as shorter reaction time, high product yields (about 90–95%), simple work up, easy removal, and reusability of the catalyst for several times without significant loss in its efficiency. This has made the protocol sustainable and economic.     

Ballistic transport in InSb mesoscopic structures

Two different device geometries are fabricated to investigate ballistic transport of electrons in low-dimensional InSb structures. Negative bend resistance is observed in four-terminal devices of channel widths ranging from 0.2 to 0.65 μm. We also report the observation of conductance quantization in quantum point contacts fabricated using in-plane gates. The one-dimensional subbands depopulate with increasing transverse magnetic field up to 3 T. Zeeman splitting is resolved at magnetic fields above 0.9 T.     

Segment densities in star and comb random-flight chains

Segment densities of comb and star branched random-flight chains have been computed. It is found that the commonly used gaussian differs more significantly for branched chains than for linear chains. The asymptotic results are also found to depend on the branching parameter g.     

Development of a Creatinine Sensor Based on a Molecularly Imprinted Polymer‐Modified Sol‐Gel Film on Graphite Electrode

An electrochemical creatinine sensor based on a molecularly imprinted polymer (MIP)‐modified sol‐gel film on graphite electrode was developed. The surface coating of MIP over sol‐gel was advantageous to obtain a porous film with outwardly exposed MIP cavities for unhindered selective rebinding of creatinine from aqueous and biological samples. A fast differential pulse, cathodic stripping voltammetric response of creatinine can be obtained after being preanodized the sensor in neutral medium containing appropriate amount of creatinine at +1.8 V versus SCE for 120 s. A linear response over creatinine concentration in the range of 1.23 to 100 μg mL^?1 was exhibited with a detection limit of 0.37 μg mL^?1 (S/N=3).     

Development and validation of stability indicating analytical method for Ilaprazole

The objective of the present study was to develop and validate a rapid and simple stability indicating analytical method for estimating Ilaprazole. Ilaprazole was subjected to different stress conditions prescribed by International Conference on Harmonization (ICH) such as hydrolysis, oxidation, photolytic and dry heat degradation conditions. The drug was very susceptible to degradation under hydrolysis and photolytic conditions, less susceptible to oxidation and stable under dry heat degradation condition. An acceptable separation of drug and its degradants was achieved by using a C-18 column and mobile phase composed of ammonium acetate buffer (pH 3.2)—acetonitrile (55: 45, v/v). Flow rate was 1 mL/min and detection wavelength was set at 303 nm. Retention time of drug was found to be 6.6 min and analysis can be completed within 10 min. The method was validated with respect to linearity, precision, accuracy, robustness, LOD and LOQ as per ICH. The method was linear (R² = 0.996) in the range of 2.5–250 μg/mL. The recovery was in the range from 99.2–100.2%.