Conductivity study of solid polyelectrolytes based on hydroiodide salt of poly(4-vinyl pyridine-co-butylmethacrylate), poly(4-vinyl pyridine-co-butylacrylate)

The chain flexibility of poly(4-vinylpyridine) was tried to increase by lowering its glass transition temperature ( T _g ) and by increasing its amorphous region by copolymerizing with butyl methacrylate and butylacrylate which act as internal plasticizer. The copolymers were prepared in five different feed molar ratios to optimize the required properties such as higher room temperature conductivity and better film-forming capacity. The conductivity and conduction behaviour of the copolymers, as well as their hydroiodide salts have been reported. There was about 10³–10⁴-fold increase in room temperature conductivity of these plasticized polyelectrolytes.     

Ciprofloxacin conjugated zinc oxide nanoparticle: A camouflage towards multidrug resistant bacteria

Gradual development of antibiotic resistant bacteria is producing severe global threat. Newer strategies are now being employed in order to control the microbial infections and to reduce the mortality as well as infection rates. Herein we describe successful synthesis of ZnO nanoparticles (ZNP) under microwave assisted condition followed by functionalization with ciprofloxacin, an antibiotic, using EDC/NHS chemistry. Successful conjugation of ciprofloxacin was confirmed by FTIR spectra. Ciprofloxacin-conjugated ZnO nanoparticles (ZN-CIP) exhibited excellent antibacterial activity against clinically isolated multidrug resistant bacterial strains of Escherichia coli, Staphylococcus aureus and Klebsiella sp. ZNP were small in size with particle size distribution 18–20 nm as obtained from transmission electron microscope (TEM). Surface topology was obtained from atomic force microscopic (AFM) image and x-ray diffraction confirmed that ZNP possessed hexagonal crystal structure. A concentration of 10 µg/mL of ZN-CIP was a benchmark concentration. During evaluation of minimum inhibitory concentration (MIC) values, similar concentration of antibiotic was incapable of producing antibacterial activity.     

Effect of Two-Dimensional Pressure on the Permittivity of Fine- and Coarse-Grained Barium Titanate

The effect two-dimensional pressure on the permittivity of fine- and coarse-grained ceramic BaTiO₃ was investigated. It was shown that, unlike coarse-grained (10° or above) barium titanate, the permittivity of the fine-grained (1μ mean) material increased with the increase in two-dimensional compression perpendicular to the electrode, whereas for an intermediate grain size, the permittivity was almost independent of pressure. The apparent anomalous effect of the fine grain size on the pressure coefficient of permittivity was explained satisfactorily on the basis of an internal stress model using a modified Devon-shire thermodynamic treatment.     

MODEL TO PREDICT THE COOL-DOWN CHARACTERISTICS OF VARIABLE AIR TEMPERATURE POTATO COLD STORAGE USING COMPUTATIONAL FLUID DYNAMICS

In Indian commercial potato cold storage facilities, the air temperature does not remain constant during the loading period. Also, because of stepwise loading pattern, the product loaded on different days would undergo different time‐temperature histories. Under this transient condition, the product takes longer to reach the steady state and loses more moisture of about 1.7% during 1 month of storage period. In addition, the sensible product‐cooling load is different for the product loaded on different days. In the present study, therefore, the product temperature, moisture loss and sensible product‐cooling load were predicted for the product loaded on different days under the condition of variable storage air temperature in the range of 3.5–10C and constant relative humidity of 90% using the computational fluid dynamics technique. It was found that the product loaded during the middle of loading period incurred more moisture loss than that loaded during early and latter stages of loading. However, the former case imposed more sensible product‐cooling load. The trends of temporal variation of average product temperature, moisture loss and sensible product‐cooling load depended on the day of loading of the product in the cold storage facility.     

Synthesis, characterization and photocatalytic reactions of phosphated mesoporous titania

Mesoporous titania nanoparticles with a well-defined mesostructure was prepared by hydrothermal process, using nonionic triblock copolymer P123 as surfactant template, modified with phosphoric acid and followed by calcination at 600°C. The sol–gel titania was modified by in situ phosphorylation using phosphoric acid and thereby incorporating phosphorous directly into the framework of TiO₂. The resulting materials were characterized by XRD, SEM, TEM, nitrogen adsorption, TGA and DRS. It was found that the structural and optical properties of titania samples are strongly influenced by their phosphate modification. In case of calcined samples a positive effect on the specific surface area for the in situ phosphated sample was found. Mesoporous structure of phosphated titania did not collapse even after calcination at 600°C. The enhanced photocatalytic activity of the synthesized phosphate nanomaterials were evaluated through a study of the decomposition of fluorescein under UV light excitation and compared with undoped titania nanomaterial as well as with commercial titania.     

A review and future prospects of renewable energy in the global energy system

Global energy consumption in the last half century has rapidly increased and is expected to continue to grow over the next 50 years,however,with significant differences.The past increase was stimulated by relatively "cheap" fossil fuels and increased rates of industrialization in North America,Europe and Japan;yet while energy consumption in these countries continues to increase,additional factors make the picture for the next 50 years more complex.These additional complicating factors include China and India's rapid increase in energy use as they represent about a third of the world's population;the expected depletion of oil resources in the near future;and,the effect of human activities on global climate change.On the positive side,the renewable energy(RE) technologies of wind,bio-fuels,solar thermal and photovoltaics(PV) are finally showing maturity and the ultimate promise of cost competitiveness.     

Adding new dimensions to laser-scanning fluorescence microscopy

We describe a novel method of optical imaging by exploiting simple ideas borrowed from pulsed optics. We show that the use of ultrafast pulsed one-photon excitation in laser-scanning fluorescence microscopy dramatically brings together several advantages offered by two widely used present day microscopic techniques, confocal and multi-photon fluorescence microscopy. The method appears as a novel tool in the context of laser-scanning fluorescence microscopy by having a 'built-in' 3D spatial resolution.     

Pyrometallurgical Preconcentration Technique for the Recovery of Copper,Nickel and Cobalt from Copper Converter Slag

Abstract

Laboratory trials of reduction-smelting of copper converter slag of M/s Hindustan Copper Limited, Ghatsila to preconcentrate the nonferrous metal values into a metallic alloy form gave an indication for its utility as a pretreatment for a subsequent hydrometallurgical processing to separate the individual metals. Although electric slag cleaning furnaces are prevalent in many copper industries, it was decided to investigate other furnace systems for full scale production, in order to make the whole process cost effective. This paper describes the effort of the R&D Centre of M/s Sandvik Asia Limited, Pune in this direction.     

STUDIES ON CRYOGENIC GRINDING OF CUMIN SEED

Studies on grinding of cumin seed at various cryogenic and ambient temperatures were conducted to observe its influence on volatile oil content and its components, particle size distribution, volume mean diameter and specific energy consumption. An increase in temperature in the cryogenic range (-160 to -70C) had no significant effect on volatile oil content, whereas increase in temperature in the ambient range (40 to 85C) significantly reduced the volatile oil content from 2.86 to 2.26 mL/100g. The volatile oil components, α-pinene, β-pinene, γ-terpinene, p-cymene and cuminaldehyde were not significantly affected by grinding temperature in the cryogenic temperature range. However, these components decreased significantly with increase in grinding temperature under ambient condition. With increase in temperature from -160 to -70C for 12 number of rotor ribs, the volume mean diameter of cumin powder increased quadratically from 129 to 164μm and the specific energy consumption increased from 72 to 108 kJ/kg.