Silica/potassium ferrite nanocomposite: Structural,morphological, magnetic,thermal and in vitro cytotoxicity analysis

The coating of silica on potassium ferrite (KFeO₂) nanoparticles has been reported in the present study. The X-ray diffraction pattern revealed the formation of orthorhombic structure of bare potassium ferrite nanoparticles, which was also retained after the silica coating, along with a broad band near 2θ ∼ 20–25° pertaining to the presence of amorphous silica. The size of bare and coated potassium ferrite nanoparticles was found to be 4–8 nm and 10–22 nm, respectively, as observed from transmission electron microscope. The presence of silica was also revealed by the Fourier transform infrared spectrum and high resolution transmission electron microscope. In vibrating sample magnetometer analysis, both bare as well as coated potassium ferrite nanoparticles exhibited superparamagnetic behaviour with magnetic saturation values, 49.01 and 21.17 emu/g, respectively. Dose-dependent cellular toxicity was observed in the in vitro MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole) – assay study on Jurkat cells, where both bare as well as silica coated nanoparticles exhibited non-toxicity below 250 μg/ml. An augmentation of cell viability was observed in case of silica coated potassium ferrite nanoparticles. The nanosize, superparamagnetic behaviour and enhanced cell viability make silica coated potassium ferrite nanoparticles a potential claimant for biomedical applications.     

A comparison of guidance cues in desktop virtual environments

Designers of educational and entertainment desktop virtual environments (VEs) have employed a variety of cues for motivating users to perform actions or adopt particular viewpoints. However, there has been little formal study comparing user responses to such cues. This paper reports the results of a preliminary study of five cues (agents, signs, man-made landmarks, environmental landmarks, and trails) for motivating actions in virtual environments. Given a sample task of navigating to a target destination, no significant differences between the cues were observed in terms of overall success or speed. However, significant differences between the cues were found on other measures, including minimization of detours (trails) and awareness of guidance (agents, signs, trails). Frequency of desktop VE usage was also found to influence performance.     

STUDIES ON FLUID CATALYTIC CRACKING OF HYDROPROCESSED FEEDSTOCKS

Worldwide public concern about environment and increased demand for better quality fuels by automobile industries has necessiated developed countries like USA, UK and Japan to stipulate stringent specifications for petroleum fuel products. Fluid catalytic cracking (FCC) is a major secondary process for fuel products and quality of products coming from FCC unit depends largely on the feedstock used. FCC naphtha makes up for 30-40% gasoline in a typical refinery pool. This FCC naphtha contributes to around 90% of the gasoline pool sulphur. Hence, sulfur and nitrogen reduction have become essential for meeting the quality requirements of fuel products resulting in the growing importance for pretreatment of FCC feedstock. In the present work, studies were carried out in pilot plant on hydrotreatment of feedstock for FCC unit. The results indicate better quality products for treated feedstock vis-a-vis untreated heavy vacuum gas oils from Persian Gulf (PG) crudes. Hydroprocessing of FCC feed has helped refiners in meeting the fuel products quality especially with feedstocks, which are characterized as heavy and refractory in nature.     

Synthesis,characterization and in vitro cytotoxicity study of calcium ferrite nanoparticles

In the present paper, calcium ferrite nanoparticles have been synthesized by the sol–gel method. The orthorhombic structure of calcium ferrite nanoparticles has been revealed by X-ray diffractometry. The morphology and size (5–10 nm) of the synthesized nanoparticles have been observed by scanning electron microscopy and transmission electron microscopy, respectively. Fourier transform infrared spectroscopy and thermogravimetric analysis have been studied, in order to ensure absence of impurities. The magnetic analysis has been studied by vibrating sample magnetometer, where the superparamagnetic behavior with saturation magnetization of 36.4 emu/g was observed. In vitro cytotoxicity test on T cell lines (Jurkat cells) using MTT (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide, a tetrazole) assay revealed the biocompatibility of the synthesized calcium ferrite nanoparticles at particle concentration below 250 µg/ml.     

Effect of Solvents for the Production of Cyclopentane by Extractive Distillation

Abstract

In view of the rapid phasing out of fluorocarbons due to their adverse ozone-depleting potential, alternative environment-friendly chemicals are being explored for blowing polyurethane, the key insulation material in refrigeration industries. Cyclopentane with required physical and thermal conductivity properties has emerged as the most appropriate alternative as it can be acquired from light petroleum hydrocarbons, which are abundant. Light naphtha is a mixture of several closely boiling hydrocarbons and hence even a narrow fractional distillation may not enrich cyclopentane for required purity and instead it results only in an azeotropic mixture. This article describes the work carried out in obtaining commercially pure cyclopentane from light naphtha through an extraction-distillation combined operation which is commonly termed as “extractive distillation.” The solvent type and key operating parameters, namely, feed naphtha cut range (heart cut), solvent/feed ratio were studied and the results obtained were further correlated with simulated model prediction.     

Shear‐induced morphology changes in N,N′‐dimethylacetamide/lithium chloride pretreated cellulose

A new mechanochemical treatment was performed on cellulose with the objective of modifying its morphology, reducing its crystallinity, and enabling better dissolution. Cellulose treated with N,N′‐dimethylacetamide (DMAc)/lithium chloride (LiCl) was subjected to shear with natural rubber as the carrier and shear‐transfer medium. When cellulose was subjected to such a mechanochemical treatment, significant changes in its surface morphology and a decrease in crystalline index were observed. The dissolution of the mechanochemically treated cellulose samples in DMAc/LiCl was found to be better compared with the dissolution of samples subjected to either mechanical shear or the chemical action of DMAc/LiCl independently. Chemical interactions between DMAc/LiCl and cellulose were enhanced synergistically under shear‐induced deformation. When shear alone was used in the absence of a DMAc/LiCl treatment, changes in the morphology, crystalline index, and dissolution were found to be negligible. The shear‐induced cellulose samples were characterized with Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and thermogravimetric analysis. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44809.     

Erosion corrosion control of 6061 aluminum alloy in multi-phase jet impingement conditions with eco-friendly green inhibitor

Erosion corrosion performance of 6061 aluminum alloy in simulated sea water slurry was investigated under multi-phase jet impingement conditions. The main objective of the work is to study erosion–corrosion of a material with engineering application and mitigate it using eco-friendly green inhibitor. Experiments were performed with the sand concentration of 0.3% and 0.3 μm size. The effect of temperature and flow rate on the performance of inhibitor was explored. Electrochemical methods were adopted for erosion-corrosion measurements. Experiments revealed that starch could mitigate erosion-corrosion with a maximum reduction efficiency of 58% at temperature of 303 K and flow rate of 4 L·min~(–1). Inhibition efficiency decreased with increase in flowrate and temperature. EIS spectrum demonstrated that the corrosion process in the presence on inhibitor was both charge transfer and mass transfer controlled. A key role of hydrodynamics in the performance of corrosion inhibitor was confirmed by the present study.     

Protection of material applied in heat exchanger under submerged jet impingement condition with Boswellia serrata: electrochemical approach

Journal of Applied Electrochemistry - Erosion–corrosion of 6061 aluminum alloy was attenuated with a green inhibitor Boswellia serrata (BWS) under submerged jet impingement condition by using...