Torsional deformation behavior of cracked gold nano-wires

The presence of in-homogeneity or defects in materials cannot be ignored. There is great need to understand the influence of defects on the mechanical response of nano-materials. In this study, atomistic simulations have been used to investigate the mechanical response of gold nano-wires under twisting. Simulations show that nano-wires have different elastic properties when defects are present. Embedded cracks of different sizes have been created in nano-wires to quantify in-homogeneity. The inter-atomic interactions are represented by employing an embedded-atom potential. The effect of different sizes of crack on potential energy, torque and stresses for investigating the mechanical response of a nano-wire is part of the whole investigation. It is predicted from our simulation that the presence of a crack and dimensions of the crack control the torsional response of gold nano-wires. Deviation in the behavior of gold nano-wires from continuum expectations is also discussed. The comparison of results of atomistic simulations is made with a linear elasticity model (of healthy and cracked nano-wires) to get deep insights into the nano-scale behavior of nano-wires.     

Effect of high or low molecular weight of components of feed on transmembrane flux during forward osmosis

The possible mechanism of water transport from feed to osmotic agent side during forward osmosis in situation when feed contains high or low molecular weight compounds and their combination has been presented. The orientation of membrane was found to influence the transmembrane flux. When the feed contains mixture of low and high molecular weight compounds mode I (feed towards the support layer) was found to result in lower flux values as compared to Mode II (feed towards active layer) due to significant external concentration polarization. Forward osmosis resulted in the concentration of betalains content in beetroot juice and anthocyanin content in grape juice from 50.92 mg/L to 2.91 g/L (57.1 fold) and from 104.85 mg/L to 715.6 mg/L (6.8 fold), respectively. Total soluble solids in case of beetroot, grape and pineapple juice were found to increase from 2.3 to 52 °Brix, from 8.0 to 54.6 °Brix from 4.4 to 54 °Brix, respectively.     

A room temperature process for making Mn2O3 nano-particles and γ-MnOOH nano-rods

Nano-size crystals of Mn₂O₃ and MnOOH have been prepared by a simple precipitation process using dilute aqueous solutions of manganese sulphate and ammonia in the presence of sodium lauryl sulphate — a surface active agent. X-ray diffraction spectrometry has been used to identify the phases and to calculate the size of the nano-size crystals using the Scherrer method. The morphology of the crystals has been studied by TEM/HRTEM and Edax has been used to estimate their elemental constituents. The sonication of the prepared nano-size material in acetone leads to the conversion of MnOOH to nano-sized Mn₂O₃.     

A measurement-based approach for power system instability early warning

Early warning of impending instability in a power system under disturbance conditions is important for preventing of system collapse. A measurement-based approach is proposed to assess the potential power system transient instability problem under cascading outages. Where a measurement-based index is obtained as the estimation accuracy of a linear autoregressive exogenous (ARX) model to estimate the dynamic response of the power system and indicate the system stability to some extent after a disturbance. The proposed approach was verified using a set of marginally stable cases in a 179-bus WECC equivalent power system.     

In situ formation of silver nanoparticles in poly(methacrylic acid) hydrogel for antibacterial applications

In this study, silver nanoparticles‐loaded poly(methacrylic acid) (PMAAc) hydrogels (HGs) have been produced by using a novel approach that involves equilibration of PMAAc HGs in aqueous solution of Ag(I) ions, followed by their reduction with borohydride. The AgNP/PMAAc composite, so produced, was characterized by scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, Fourier‐transform infrared, surface plasmon resonance, and differential scanning colorimetry analysis. The composite demonstrated pH‐dependent swelling behavior. The AgNP/PMAAc composites demonstrated fair antibacterial action against Escherichia coli. Their biocidal action was found to depend on the concentration of silver present within the HG and degree of crosslinking of HGs. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers     

Solid particle erosion wear characteristics of fiber and particulate filled polymer composites: A review

The solid particle erosion behaviour of fiber and particulate filled polymer composites has been reviewed. An overview of the problem of solid particle erosion was given with respect to the processes and modes during erosion with focus on polymer matrix composites. The new aspects in the experimental studies of erosion of fiber and particulate filled polymer composites were emphasised in this paper. Various predictions and models proposed to describe the erosion rate were listed and their suitability was mentioned. Implementation of design of experiments and statistical techniques in analyzing the erosion behaviour of composites was discussed. Recent findings on erosion response of multi-component hybrid composites were also presented. Recommendations were given on how to solve some open questions related to the structure-erosion resistance relationships for polymers and polymer based hybrid composites.     

Morphology, thermal, electrical and electrochemical stability of nano aluminium-oxide-filled polyvinyl alcohol composite gel electrolyte

In the present work, an attempt has been made to develop nano aluminium oxide (Al₂O₃)-filled polyvinyl alcohol (PVA) composite gel electrolytes. Surface morphological studies, thermal behaviour, electrochemical stability and electrical characterization of these composite gel electrolytes have been performed. An increase in the concentration of Al₂O₃ in composite gel electrolytes increases the amorphous characteristics of pure PVA. Bulk conductivity of composite gel electrolytes increases by an order of magnitude on addition of a nano filler. Maximum conductivity of 5·81 × 10^?2 S/cm is observed for 6 wt% Al₂O₃-filled polymer gel composite electrolytes. Temperature dependence of electrical conductivity shows a combination of Arrhenius and Vogel-Tamman-Fulcher (VTF) nature. Maximum current stability during oxidation and reduction cycle is noticed for 6 wt% Al₂O₃-filled PVA composite electrolyte, viz. ±1·65 V.     

Effect of Degree of Polishing on Milling Characteristics and Proximate Compositions of Barnyard Millet (Echinochloa frumentacea)

Polishing of barnyard millet was done in rice polisher. Degree of polishing was obtained from 3 to 6 min time of milling at an increment of 1 min at 8%, 10%, 12% and 14% of moisture levels. At each moisture level and degree of polishing, proximate compositions (protein, fat, fibre, ash and carbohydrates) were analysed. At 8% moisture, barnyard millet was more resistant to polishing and yielded 18.86% of bran after 6 min of milling, while at 14% moisture it was 19.21%. The amount of bran removed increased significantly with time of milling and was best described by power model when regression analysis was carried out. The milling and head yield decreased linearly with the degree of polishing. For the entire range of milling time, at 10% moisture content, there was highest head yield (52.97%). The broken millet recovery increased in proportion to the degree of polishing. Regression analysis showed that the power model was the best fit. The milling time caused a reduction in the proximate compositions. The maximum loss in protein, fat, ash and fibre took place at 14% moisture content followed by 12%, 10% and 8% moisture levels. Protein, fat, ash and fibre were negatively and linearly correlated with degree of polishing.     

Effect of frying cycles on physical,chemical and heat transfer quality of rice bran oil during deep-fat frying of poori: An Indian traditional fried food

The present work deals with the effect of frying cycles on physical, chemical and heat transfer quality of rice bran oil (RBO) during the preparation of poori (an Indian traditional fried food) by deep-fat frying. The frying was carried out in intermittent mode (5 batches each for 3 min in a day without any time lag) and repeated for 6 frying cycles. Result indicated that in first two cycles, free fatty acid content, peroxide value and total polar materials increased, while radical scavenging activity decreased. Further increase in frying cycles did not result in any significant changes in these parameters (p > 0.05). Similar trends were observed for these parameters in case of heating. Relative amounts of total saturated fatty acids increased due to marginal decrease in total unsaturated fatty acids content during frying cycles, however, no significant change was observed during heating. The convective heat transfer coefficient was found to decrease with an increase in frying cycle due to increase in kinematic viscosity of RBO for every frying or cycles. Despite the marginal changes in physical and chemical properties, there was no significant difference (p > 0.05) in the sensory characteristics of poori prepared in oil subjected to different cycles of frying.