Microstructure determination of isobornyl methacrylate-styrene copolymer by NMR spectroscopy

An investigation of the microstructure of isobornyl methacrylate - styrene (I/S) copolymers prepared by the atom transfer radical polymerization (ATRP) using methyl-2-bromopropionate as an initiator and PMDETA copper complex as catalyst under nitrogen atmosphere at 70 °C has been done by two-dimensional NMR techniques. 2D- HSQC and TOCSY have been utilized to resolve the complex ¹H NMR spectrum and to establish the compositional and configurational sequences of isobornyl methacrylate-styrene (I/S) copolymers. 2D HSQC and TOCSY spectra showed compositional and configurational sensitivity of α-methyl carbon of I unit and methine proton of S unit and are assigned up to the triad level. The methylene carbon (C₁₀) also shows triad level of compositional sensitivity in 2D HSQC spectra. Heteronuclear multiple-bond correlation (HMBC) spectroscopy has been used to study carbonyl/quaternary carbon-proton coupling. The carbonyl and quaternary carbons showed compositional and configurational sensitivity upto the triad level. The values of reactivity ratios were determined by Kelen-Tudos (KT) and nonlinear error in variable method (RREVM) using copolymer composition data that were determined by ¹H NMR spectrum. Reactivity ratios of co-monomers in I/S copolymer, determined from a linear Kelen-Tudos method (KT) and non-linear Error-in-Variable Method (EVM), are r_I?=?0.39?±?0.09, r_S?=?0.44?±?0.08 and r_I?=?0.42, r_S?=?0.47, respectively.     

Modification of polypropylene through intercrosslinking graft copolymerization of poly(vinyl alcohol): Synthesis and characterization

Modification of polypropylene (PP) has been successfully carried out through intercrosslinking of poly(vinyl alcohol) (PVA), by chemical graft copolymerization method using benzoyl peroxide (BPO) as radical initiator. Prior to grafting, PP was irradiated by gamma rays at a constant dose rate of 3.40 kGy/h to introduce hydroperoxide groups. Optimum conditions pertaining to maximum percentage of grafting were evaluated as a function of different reaction parameters. Maximum percentage ofgrafting of PVA (75%) was obtained at [BPO] = 5.51 × 10^?2 mol/L in 120 min at 70°C using 15 mL of water. Characterization of pristine PP and PP‐g‐PVA was carried out by FTIR, thermogravimetric analysis, and scanning electron micrography. Swelling studies were carried out in pure, binary, ternary, and quaternary solvent systems comprising of water, ethanol (EtOH), dimethylsulfoxide (DMSO) and N, N‐dimethylformamide (DMF) in different ratios. Maximum swelling values of PP‐g‐PVA (both composite and true graft) was observed in pure DMSO followed by DMF, EtOH, and water and it was also higher than that observed in mixed solvent system. Water retention studies of pristine PP and PP‐g‐PVA (both composite and true graft) were investigated at different time periods, temperature, and pH. Maximum % water retention of PP‐g‐PVA (composite) (108%) was observed in 8 h at 50°C in neutral medium (pH = 7). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Dimerisation of the Yeast K+ Translocation Protein Trk1 Depends on the K+ Concentration

In baker’s yeast (Saccharomyces cerevisiae), Trk1, a member of the superfamily of K-transporters (SKT), is the main K⁺ uptake system under conditions when its concentration in the environment is low. Structurally, Trk1 is made up of four domains, each similar and homologous to a K-channel α subunit. Because most K-channels are proteins containing four channel-building α subunits, Trk1 could be functional as a monomer. However, related SKT proteins TrkH and KtrB were crystallised as dimers, and for Trk1, a tetrameric arrangement has been proposed based on molecular modelling. Here, based on Bimolecular Fluorescence Complementation experiments and single-molecule fluorescence microscopy combined with molecular modelling; we provide evidence that Trk1 can exist in the yeast plasma membrane as a monomer as well as a dimer. The association of monomers to dimers is regulated by the K⁺ concentration.     

Synthesis and characterization of polypropylene‐grafted gelatin

Modification of polypropylene (PP) has been successfully carried out by graft copolymerization of gelatin, by chemical method using benzoyl peroxide (BPO) as radical initiator. PP was preirradiated by gamma rays at a constant dose rate of 3.40 kGy/h before grafting to introduce hydroperoxide groups. Optimum conditions pertaining to maximum percentage of grafting were evaluated as a function of different reaction parameters. Maximum percentage of grafting of gelatin (115%) was obtained at BPO concentration = 4.132 × 10^?2 mol/L in 120 min at 70°C using 30 mL of water. Characterization of PP‐g‐gelatin was carried out through FTIR, thermogravimetric analysis, and scanning electron microscopy. Swelling studies were carried out in pure, binary, ternary, and quaternary solvent systems comprising distilled water, ethanol, dimethylsulphoxide (DMSO), and N,N‐dimethylformamide (DMF) in different ratios. Maximum swelling of PP‐g‐gelatin (both composite and true graft) was observed in pure solvents that is, DMSO followed by DMF, ethanol, and water and was higher than that observed in the mixed solvent system. Water retention studies of unmodified PP, that is, pristine PP and PP‐g‐gelatin (both composite and true graft) were investigated at different time periods, temperatures and pH. Maximum % water retention for PP‐g‐gelatin (composite; 170%) was observed in 8 h at 50°C in neutral medium (pH = 7). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Human-vision-based real-time stereopsis

The progression in the field of stereoscopic imaging has resulted in impressive 3D videos. This technology is now used for commercial and entertainment purposes and sometimes even for medical applications. Currently, it is impossible to produce quality anaglyph video using a single camera under different moving and atmospheric conditions with the corresponding depth, local colour, and structural information. The proposed study challenges the previous researches by introducing single camera based method for anaglyph reconstruction and it mainly concentrates on human visual perception, where as the previous methods used dual camera, depth sensor, multi view, which demand not only long duration they also suffer from photometric distortion due to variation in angular alignment. This study also contributes clear individual image without any occlusion with another image. We use an approach based on human vision to determine the corresponding depth information. The source frames are shifted slightly in opposite directions as the distance between the pupils increases. We integrate the colour components of the shifted frames to generate contrasting colours for each one of the marginally shifted frames. The colour component images are then reconstructed as a cyclopean image. We show the results of our method by applying it to quickly varying video sequences and compare its performance to other existing methods.     

Microstructure and Corrosion Characterization of Squeeze Cast AM50 Magnesium Alloys

Squeeze casting of magnesium alloys potentially can be used in lightweight chassis components such as control arms and knuckles. This study documents the microstructural analysis and corrosion behavior of AM50 alloys squeeze cast at different pressures between 40 and 120 MPa and compares them with high-pressure die cast (HPDC) AM50 alloy castings and an AM50 squeeze cast prototype control arm. Although the corrosion rates of the squeeze cast samples are slightly higher than those observed for the HPDC AM50 alloy, the former does produce virtually porosity-free castings that are required for structural applications like control arms and wheels. This outcome is extremely encouraging as it provides an opportunity for additional alloy and process development by squeeze casting that has remained relatively unexplored for magnesium alloys compared with aluminum. Among the microstructural parameters analyzed, it seems that the β-phase interfacial area, indicating a greater degree of β network, leads to a lower corrosion rate. Weight loss was the better method for determining corrosion behavior in these alloys that contain a large fraction of second phase, which can cause perturbations to an overall uniform surface corrosion behavior.     

Comparative Analysis of Multi-scale Wavelet Decomposition and k-Means Clustering Based Text Extraction

Wireless Personal Communications - Text present in images provides important information for automatic annotation, indexing and retrieval. Therefore, its extraction is a well-known research area in...     

Exceptional Water Desalination Performance with Anion‐Selective Electrodes

Capacitive deionization (CDI) typically uses one porous carbon electrode that is cation adsorbing and one that is anion adsorbing. In 2016, Smith and Dmello proposed an innovative CDI cell design based on two cation‐selective electrodes and a single anion‐selective membrane, and thereafter this design was experimentally validated by various authors. In this design, anions pass through the membrane once, and desalinated water is continuously produced. In the present work, this idea is extended, and it is experimentally shown that also a choice for anion‐selective electrodes, in combination with a cation‐selective membrane, leads to a functional cell design that continuously desalinates water. Anion‐selective electrodes are obtained by chemical modification of the carbon electrode with (3‐aminopropyl)triethoxysilane. After chemical modification, the activated carbon electrode shows a substantial reduction of the total pore volume and Brunauer–Emmett–Teller (BET) surface area, but nevertheless maintains excellent CDI performance, which is for the first time that a low‐porosity carbon electrode is demonstrated as a promising material for CDI.     

Intrinsic Sub-Nanocrystalline Silicon Thin Films: Active Layer for Solar Cells

Silicon - The study presents the typical aspects of silicon thin films in terms of growth under variation of applied power using Radio frequency Plasma Enhanced Chemical Vapor Deposition technique...     

A unified approach for detection of Clickbait videos on YouTube using cognitive evidences

Applied Intelligence - Clickbait is one of the form of false content, purposely designed to attract the user’s attention and make them curious to follow the link and read, view, or listen to...