Effect of electron beam irradiation on the mechanical,thermal, and dynamic mechanical properties of flyash and nanostructured fly ash waste polyethylene hybrid composites

The effect of electron beam irradiation on the technical properties of fly ash (FA) and nano fly ash (NFA)‐filled waste polyethylene (WPE) composites have been investigated in this article. It is observed that the FA/NFA at 5 wt% imparted enhanced technical properties. The modified composites were prepared by three different methods (1) modification of WPE matrix first by grafting with maleic anhydride (MA) and preparing the composite (2) Preparing WPE‐FA/NFA composites and subjecting to electron beam irradiation. (3) Subjecting the FA/NFA to electron beam radiation first and then preparing composites with WPE. Of the three methods, the composite prepared and then electron beam irradiated gave the best balance in the physico‐mechanical properties. The tensile and flexural strength of WPE increased from 21.2 MPa and 25.4 MPa to 33.0 MPa (57.8%) and 45.8 MPa (72%) respectively at 5 wt% FA‐filled WPE composites, which further increased to 34.5 MPa (65%) and 47.7 MPa (87.8%) respectively with 5 wt% of NFA‐filled WPE composites, after electron beam irradiation. The thermal stability was enhanced upon electron beam irradiation of the composites. The dynamic mechanical properties reveal that the storage modulus reaches the highest value for the irradiated composite corroborating with the flexural modulus throughout the temperature range studied. The fractured surfaces were examined under SEM and were correlated with the mechanical properties. The results indicate that FA/NFA reinforced WPE composites act as an excellent stress raisers preventing crack propagation and enhancing the performance properties on electron beam irradiation. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers     

Effect of aspect ratio on natural convection in power-law liquids from a heated horizontal elliptic cylinder

The influence of aspect ratio and shear-dependent viscosity on free convection heat transfer from a horizontal heated elliptic cylinder in power-law fluids has been investigated. In particular, the coupled momentum and energy equations have been solved numerically over the following ranges of conditions: Grashof number, 10 ? Gr ? 10⁵; Prandtl number, 0.72 ? Pr ? 100; power-law index, 0.3 ? n ? 1.5 and aspect ratio, 0.2 ? E ? 5. The new extensive results demonstrate the influence of the Grashof number (Gr), Prandtl number (Pr), power-law index (n) and aspect ratio (E) on the macroscopic heat and momentum transfer characteristics like local and average values of Nusselt number (Nu) and drag coefficients (C_D). Further insights are developed by examining the structure of the flow and temperature fields adjacent to the cylinder. Broadly speaking, all else being equal, shear- thinning fluid behaviour promotes heat transfer whereas shear-thickening viscosity has a deleterious effect on it with reference to that in Newtonian fluids. Also, the rate of heat transfer gradually increases as the cylinder shape passes from blunt to slender with respect to the direction of gravity. Finally, the present numerical values of the Nusselt number are correlated using a simple analytical form which facilitates interpolation of the present results for the intermediate values of the governing parameters. The paper is concluded by presenting detailed comparisons with the previous numerical and experimental results available in the literature, especially in Newtonian fluids.     

Synthesis and characterization of chitosan‐polycaprolactone blended with organoclay for control release of doxycycline

In the present research program, chitosan has been mixed with polycaprolactone (PCL) (80 : 20) for using them for control delivery of doxycycline. Organoclay, Cloisite 30B of different concentrations 1, 2.5, and 5% has been blended with the composite. Chitosan is a natural biodegradable polymer where as polycaprolactone is a synthetic biopolymer. The blending of the two polymers has been carried out varying the proportion of nanoclay so that the composite can be a better drug carrier. The blends were characterized by Fourier Transmission Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X‐ray Diffraction (XRD) analysis. From the FTIR spectra, the various groups present in chitosan and PCL blend were monitored. The homogeneity, morphology, and crystallinity of the blends were ascertained from SEM and XRD data, respectively. The swelling studies have been carried out at different drug loading. Swelling study is an important parameter to predict the diffusion of the drugs from the matrix. The kinetics of the drug delivery system has been systematically studied. Drug release kinetics was analyzed by plotting the cumulative release data versus time by fitting to an exponential equation which indicated the non‐Fickian type of kinetics. The drug release was investigated at different pH medium, and it was found that the drug release depends upon the pH medium as well as the nature of matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Analysis of Conduction and Radiation Heat Transfer in a Differentially Heated 2‐D Square Enclosure

Radiative heat transfer with and without conduction in a differentially heated 2‐D square enclosure is analyzed. The enclosure with diffuse gray boundaries contains radiating and/or conducting gray homogeneous medium. Radiatively, the medium is absorbing, emitting and scattering. On the south boundary, four types of discrete heated regions, viz., the full boundary, the left one‐third, left two third and middle one third, are considered. In the absence of conduction, distributions of heat flux along the south boundary are studied for the effect of extinction coefficient. In the presence of conduction, distributions of radiation, conduction and total heat fluxes along the south boundary are analyzed for the effects of extinction coefficient, scattering albedo, conduction–radiation parameter, and south boundary emissivity. Effects of these parameters on centerline temperature distribution are also studied. To assess the performance of three commonly used radiative transfer methods, in all cases, the radiative transfer equation is solved using the discrete ordinate method (DOM), the conventional discrete ordinate method (CDOM) and the finite volume method (FVM). In the combined mode problem, with volumetric radiative information known from one of the three methods, viz., DOM, CDOM, and FVM, the energy equation is solved using the finite difference method (FDM). In all cases, the results from FDM‐DOM, FDM‐CDOM, and FDM‐FVM are in good agreement. Computationally, all three sets of methods are equally efficient.     

Preparation and Characterization of Edible Films Based on Soy Protein Isolate-Fatty Acid Blends

Edible films containing soy protein isolate, long-chain fatty acids, and cross-linkers using glycerol as the plasticizer have been prepared. FTIR spectra reveal the presence of different groups present in the biofilms. The WVP value is highest in the case of films with 10% oleic acid and decreases with increasing concentration. The thermal degradation pattern and the tensile properties of the films have been discussed. The XRD values indicate that the SPI films remain mostly in the amorphous state. From the SEM picture, it is evident that the fatty acids act as modifier, furfural as the cross-linker, and ZnCl₂ as the coordinator.     

Structure-Based Virtual Screening and in vitro and in vivo Analyses Revealed Potent Methyltransferase G9a Inhibitors as Prospective Anti-Alzheimer's Agents

G9a is a lysine methyltransferase able to di-methylate lysine 9 of histone H3, promoting the repression of genes involved in learning and memory. Novel strategies based on synthesizing epigenetic drugs could regulate gene expression through histone post-translational modifications and effectively treat neurodegenerative diseases, like Alzheimer's disease (AD). Here, potential G9a inhibitors were identified using a structure-based virtual screening against G9a, followed by in vitro and in vivo screenings. First, screening methods with the AD transgenic Caenorhabditis elegans strain CL2006, showed that the toxicity/function range was safe and recovered age-dependent paralysis. Likewise, we demonstrated that the best candidates direct target G9a by reducing H3 K9me2 in the CL2006 strain. Further characterization of these compounds involved the assessment of the blood-brain barrier-permeability and impact on amyloid-β aggregation, showing promising results. Thus, we present a G9a inhibitor candidate, F , with a novel and potent structure, providing both leads in G9a inhibitor design and demonstrating their participation in reducing AD pathology.     

Synthesis and characterization of waterborne epoxy derived from epoxidized soybean oil and bioderived C-36 dicarboxylic acid

This study focuses on synthesis of waterborne epoxy (WBE) derived from epoxidized soybean oil (ESO) and its compatibility with water-dispersible curing agent Pripol 1009, which is a bioderived long-chain dimer acid. The reaction parameters involved in the synthesis of WBE from ESO have been optimized based on physicochemical properties like hydroxyl value, epoxy equivalent value and degree of solubility of WBE. The WBE obtained after 5 and 6 h of reaction time was found to be of optimum composition with balanced physicochemical properties. The mechanical, thermal and physicochemical properties of WBE obtained after 6 h of reaction time revealed relatively better performance characteristics as compared to ESO.     

Effect of mineral geology, mineral size and settling time on selective dispersion and separation process for recovering iron value from iron ultra fines

The dispersion study was conducted on ultra fines of iron ore collected from two locations, Joda and Noamundi slime ponds in the states of Orissa and Jharkhand (India) respectively using sodium hexametaphosphate as a dispersing agent. The Joda slime has been separated into two parts by using hydro cyclone to identify the effect of particle size on selective dispersion and separation of iron ore slimes. Among the gangue minerals present in the slimes, zeolite is more selective towards separation through dispersion process. Under a particular settling condition, a high grade concentrate containing 67.9 wt.% Fe, 1.2 wt.% Al₂O₃ and 1.25 wt.% SiO₂ with 58% iron recovery is achievable using off grade iron ultra fines containing 57.8 wt.% Fe, 7.55 wt.% Al₂O₃ and 7.15 wt.% SiO₂.The efficiency of selective dispersion process strongly depends on mineral geology and particle size. The iron ore ultra fines collected from the Joda slime pond have better selectivity towards dispersion resulting in better separation of gangue minerals in comparison to iron ore ultra fines collected from Noamundi slime pond. This can be attributed to better liberation of Joda slime and difference in nature of the mineral content in Noamundi slime.     

Response of Phase Transformation Inducing Heat Treatments on Microstructure and Mechanical Properties of Reduced Activation Ferritic-Martensitic Steels of Varying Tungsten Contents

Microstructure and mechanical properties of 9Cr-W-0.06Ta Reduced Activation Ferritic-Martensitic (RAFM) steels having various tungsten contents ranging from 1 to 2 wt pct have been investigated on subjecting the steels to isothermal heat treatments for 5 minutes at temperatures ranging from 973 K to 1473 K (700 °C to 1200 °C) (below Ac₁ to above Ac₃) followed by oil quenching and tempering at 1033 K (760 °C) for 60 minutes. The steels possessed tempered martensite structure at all the heat-treated conditions. Prior-austenitic grain size of the steels was found to decrease on heating in the intercritical temperature range (between Ac₁ and Ac₃) and at temperatures just above the Ac₃ followed by increase at higher heating temperatures. All the steels suffered significant reduction in hardness, tensile, and creep strength on heating in the intercritical temperature range, and the reduction was less for steel having higher tungsten content. Strength of the steels increased on heating above Ac₃ and was higher for higher tungsten content. Transmission Electron Microscopy (TEM) investigations of the steels revealed coarsening of martensitic substructure and precipitates on heating in the intercritical temperature range, and the coarsening was relatively less for higher tungsten content steel, resulting in less reduction in tensile and creep strength on intercritical heating. Tensile and creep strengths of the steels at different microstructural conditions have been rationalized based on the estimated inter-barrier spacing to dislocation motion. The study revealed the uniqueness of inter-barrier spacing to dislocation motion in determining the strength of tempered martensitic steels subjected to different heat treatments.