Facile one‐pot synthesis of linear and radial block copolymers of styrene and isoprene through a novel coupling agent by living anionic polymerization

A new methodology is successfully used for the concurrent synthesis of three different copolymers; diblock, triblock, and three‐armed star‐block copolymers of styrene and isoprene via the living anionic polymerization with control over the molecular weight and weight fractions of each block. The room temperature polymerization process has resulted in the well defined linear and radial block copolymers, when the living di‐block of poly(styrene‐b‐isoprene) was coupled using cheap and readily available malonyl chloride as a novel coupling agent giving nearly 100% yield. The resulting block copolymers have narrow polydispersity index (PDI = 1.01–1.09) with a good agreement between the calculated and the observed molecular weights. The results are further supported by fractionation of the block copolymers by reversed‐phase temperature gradient interaction chromatography (RP‐TGIC) technique followed by size exclusion chromatography (SEC). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2636–2641, 2010     

Modeling of a Rotary Drum Granulator for Control

A phenomenological model with 12 parameters for rotary drum granulation with the help of material balance equations taking into account the growth and death functions was developed. Experiments were conducted and the data were used to obtain model parameters with reference to the operating conditions and for validation of the model. It was concluded that the proposed model is adequate for the representation of dynamics and hence this model can be recommended for dynamic simulation leading to improved control of granulation circuits.     

Adsorption studies of cesium on a new inorganic exchanger ammonium molybdophosphate-alumina (AMP-Al2O3)

The applicability of ammonium molybdophosphate-alumina (AMP-Al₂O₃) for the efficient removal of Cs from aqueous solution by adsorption has been investigated. The kinetics of adsorption of cesium ions has been studied by using radioanalytical procedure over a concentration range of 10⁻⁴−10⁻² mol.dm⁻³ and in the temperature range of 303–318 K. The results showed that the uptake follows the first order rate law with respect to cesium concentration and obeys Langmuir and modified Freundlich adsorption isotherm in the concentration range studied. Equilibrium adsorption values at different temperatures have been utilised to evaluate change in standard thermodynamic parameters (ΔH ⁰, ΔG ⁰ and ΔS ⁰). From the thermodynamic parameters it is found that the process is exothermic in nature.     

Parity of the band head at 3710 keV in 99Rh using clover detector as compton polarimeter

Clover detector has been used as a Compton polarimeter to measure the linear polarization of γ-rays produced in heavy ion fusion reaction. The polarization sensitivity of the clover detector has been measured over γ-ray energies ranging from 386 to 1368 ke V. The E1 multipolarity of the 1117 keV transition in ⁹⁹Rh has been established using this polarimeter. This has resulted in the assignment of negative parity to the band head at 3710 keV in ⁹⁹Rh.     

A servicing strategy for items sold under warranty

When repairable items sold under warranty fail, the rectification action taken by the manufacturer can be either a repair or a replacement. In this paper a new repair–replacement strategy is proposed for the manufacturer when the items are sold with a non-renewing free replacement warranty policy. The strategy involves splitting the warranty period into two intervals where only repairs are carried out, separated by a third interval with at most one replacement.     

Threshold photoproduction of charged pions on14N

Pion photoproduction processes¹⁴N_gs(γ, π ⁺)¹⁴C and¹⁴N_gs(γ, π ^?)¹⁴O have been studied in the threshold region. These processes provide an excellent tool to study the corrections to soft pion theorems and Kroll-Ruderman limit as applied to nuclear processes. The agreement with the available experimental data for these processes is better with the empirical wave functions while the shell-model wave functions predict a much higher value. Detailed experimental studies of these reactions at threshold, it is shown, are expected to lead to a better understanding of the shell-model inputs and radial distributions in the 1p state.     

Lot sizing and testing for items with uncertain quality

We consider the problem where items are produced in lots and sold with warranty. Due to manufacturing variability, some items do not conform to the design specifications and their performance is inferior (for example, have higher failure rate). The warranty servicing cost for these is much higher than for those which conform. Two approaches have been advocated for reducing the warranty cost per item released and in both it is achieved at the expense of increased manufacturing cost. The first involves life testing to weed out nonconforming items and the second involves strategies to reduce nonconforming items being produced. In this paper, the authors develop a model which combines both approaches and quality control decisions are made optimally to minimize the total (manufacturing and warranty) cost. It extends the earlier models of the authors which deals with quality decisions based solely on either the first or the second approach.     

Potential energy curves for theB 2 Σ andX 2 Σ states of scandium monoxide

For theB ² Σ andX ² Σ states of scandium monoxide, the potential energy curves are constructed by the Rydberg-Klein-Rees and the Morse methods. Morse model is shown to be adequate for the (B→X) band system of ScO. The r_e values are found to be 1.717 Å and 1.665 Å for theB andX states respectively.     

The use of CNDO/force and compliance constant methods in evaluating quadratic potential functions of carbonyl and formyl fluorides

CNDO/Force and compliance constant methods were applied to define general quadratic potential functions for F₂CO and HCOF. A satisfactory set of compliants was obtained by suitably scaling down the stretching and stretch–stretch elements of the initial force constant matrix, evaluated by the CNDO/force approach, followed by fitting the compliants to available experimental data.