Copolyperoxides of 2-(acetoacetoxy)ethyl methacrylate with methyl methacrylate and styrene; Synthesis,characterization, thermal analysis,and reactivity ratios

Copolyperoxides of 2-(acetoacetoxy)ethyl methacrylate (AEMA) with styrene (St) and methyl methacrylate (MMA) of different compositions have been synthesized in the presence of 2,2′-azobisisobutyronitrile as a free radical initiator under 100 psi oxygen pressure at 50 °C. The rates of oxidative copolymerization reactions are determined from the oxygen consumption (Δp) against time plot. Highly exothermic thermal degradations of these copolyperoxides are studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) and degradation products have been characterised by electron-impact mass spectroscopy (EI-MS). The NMR spectroscopy and EI-MS analysis confirm the alternating peroxy bonds in the main chain. The monomer reactivity ratios are computed by the Fineman–Ross and Kelen–Tüdös methods, using compositions obtained from ¹H and ¹³C NMR analysis. These copolymers can potentially be used as polymeric initiators for the radical polymerization of vinyl monomers, autocombustible fuel. Also, the β-carbonyl moieties along the side chain of the copolyperoxides can be utilized to prepare degradable polyperoxide–metal complexes.     

Influence of self-doped poly(aniline-co-4-amino-3-hydroxy-naphthalene-1-sulfonic acid) on corrosion inhibition behaviour of iron in acidic medium

This paper presents the corrosion inhibition performance of soluble self-doped copolymers of aniline and 4-amino-3-hydroxy-naphthalene-1-sulfonic acid synthesized by chemical oxidative polymerization method. The corrosion inhibition behaviour of the copolymers in 1.0 M HCl has been evaluated using Tafel Extrapolation method and electrochemical impedance spectroscopy (EIS) which was also used to propose the mechanism besides surface morphology. The results showed that the copolymer film exhibited the significant shifting in the corrosion potential and greater charge transfer resistance. The corrosion inhibition efficiency was found to increase from 50% to 90% by increasing the concentration of copolymer from 10 to 70 mg/l in HCl medium. Moreover, the copolymer showed the larger degree of surface coverage onto the iron surface, reflecting the higher inhibition for corrosion of the iron in highly acidic medium.     

Polarographic study of the Reduction of Cadmium(II) and Lead(II) in DL-norleucine media

In continuation of our earlier work on the electrochemical behaviour of amino acids and their metal complexes [1–3], the present investigation reports the polarographic behaviour of Cd(II) and Pb(II) in presence of DL-norleucine, formation and composition of their complexes, determination of stability constants by DE FORD and HUME'S method [4] and MIHALLOV'S mathematical approach [5] at 20° and 30°C and also thermodynamic parameters accompanying complexation reactions at 20°C.     

Synthesis, Structural and Magnetic Properties of Polypyrrole Coated Ni0.2Ca0.8Fe2O4 Nanocomposite

The nanoparticles of spinel ferrites having composition Ni_0.2Ca_0.8Fe₂O₄ were synthesized by an advanced sol-gel method and subsequently coated with intrinsically conducting polypyrrole (PPy) by chemical oxidative polymerization of the corresponding monomer (pyrrole) using ammonium peroxodisulphate as oxidant. The X-ray diffraction and TEM measurements were obtained to understand the crystalline structure, size and morphology of evolution of the samples. The dc electrical investigation revealed that at room temperature the surface conductivity increased from 2.8×10^?5 S?cm^?1 to 1.5×10^?3 S?cm^?1 on polymerization. M?ssbauer investigations revealed that the polymerization causes migration of Fe³⁺ ions from A to B site, resulting to the enhancement of the observed hyperfine field. In agreement with this, the dc magnetization measurements performed on VSM revealed an enhancement in saturation magnetization in the M?CH curves on polymerization. The value of blocking temperature (T _B) is found to have credibly increased from 110 K to 130 K, which confirms the increase in crystallite size after polymerization.     

Comment on “Robust guaranteed cost control for a class of two-dimensional discrete systems with shift-delays”

This paper points out some technical errors in the derivation of main results in the above paper and present the results in corrected form.     

A quad 500 MHz waveform digitizer with differential trigger for use in the muon g-2 experiment

We have developed and tested a 4 channel, 500 MHz, 512 k sample, 8 bit waveform digitizer in a FASTCAMAC module. A novel feature is the implementation of a sparse scan during readout with a programmable differential trigger to reduce the data to a manageable level. The differential trigger allows reliable detection of pulses with low threshold in the presence of a variable baseline.     

Release kinetics of nisin from biodegradable poly(butylene adipate-co-terephthalate) films into water

The release kinetics of nisin from poly(butylene adipate-co-terephthalate) (PBAT) to distilled water was studied at of 5.6, 22 and 40 °C. The release kinetics of nisin from PBAT film was described using Fick’s second law of diffusion, partition coefficient, and Weibull model. The diffusion coefficients (D) determined were 0.93, 2.29, and 5.78 × 10⁻¹⁰ cm²/s at 5.6, 22, and 40 °C, respectively. The partition coefficients (K) calculated were 0.84, 3.89, and 5.2 × 10³ at 5.6, 22, and 40 °C, respectively. The nisin release data at selected temperatures were fitted with the Weibull model (R² > 0.97) with b and n values ranging from 0.02 to 0.98 and from 0.28 to 0.45, respectively. The temperature dependence of D, K, and Weibull model parameter b was modeled using the Arrhenius equation giving values of activation energy (E_a) of 38.3 kJ mol⁻¹ (for D), 38.5 kJ mol⁻¹ (for K), and 79.5 kJ mol⁻¹ (for b).     

Applications of biofiltration in drinking water treatment – a review

Biofiltration is a process in which an otherwise conventional granular filter is designed to remove not only fine particulates but also dissolved organic compounds through microbial degradation. Biofiltration can reduce the need for chemicals in drinking water treatment and thus improved applications of biofiltration in drinking water treatment can be viewed as green or sustainable engineering technology. Recent trends in biofiltration technology for drinking water treatment have or have attempted to extend the performance of biofilters through gaining a better understanding of operational constraints. This review articles summarizes important operational parameters influencing biofiltration performance such as hydraulic loading, empty bed contact time (EBCT), temperature, media type, and backwashing conditions. In addition, recent advancements in biofiltration operations including, ozonation, ammonia removal and the influence of nutrient (nitrogen, phosphorous) supplementation to facilitate carbon removal are explored. ? 2015 Society of Chemical Industry