Microstructure studies in Al-6% Si-1.9% Cu-x% Mg alloys

The nature of precipitates formed in the aged Al-6% Si-1.9%Cu-x%Mg alloys (where x varies from 0.2 to 1.13) was investigated using scanning and transmission electron microscopy. Vickers hardness and grain size were measured. Results showed peak hardness around 4 and 10 h ageing time for 0.54% Mg and 1.13% Mg alloy, respectively. Hardness was found to increase with increasing magnesium content except for the 1.13% Mg alloy aged for 10 h. Q-phase particles have been observed and these are most probably responsible for the variation of hardness.     

Remote sensing for flow induced vibrations in the PARR-1 core assembly

Reactor core vibrations of the Pakistan Research Reactor-1 (PARR-1) have been investigated using remote technique and mechanical accelerometers. The signals taken from the reactor core grid plate and at the support structure have been compared to find out the damping. For remote sensing technique, a 1 mW He–Ne laser has been used to detect the vibration signal reflected from the mirror fixed at the dummy fuel assembly on a grid plate. In comparison with the vibrations at the core and at the support structure, it was observed that the vibrations were damped by a factor of 38%.     

The electrical characteristics of metal–semiconductor hetero-structures with graphene oxide and perylenetetracarboxylic dianhydride interface

Journal of Materials Science: Materials in Electronics - In this study, we investigated the electrical properties of Al/p-Si, Al/GO/p-Si, Al/PTCDA/p-Si and Al/GO-PTCDA/p-Si structures were examined...     

X-ray diffraction analysis of silicon prepared from rice husk ash

Polycrystalline silicon has been prepared by metallothermal reduction of rice husk ash, which contains a considerable amount of amorphous silica. Acid-leached rice husk was burnt at a temperature of 620° C to obtain rice husk ash (RHA). RHA was then reduced with magnesium and major impurities were minimized or removed by an acid leaching process. The end-product was analysed using X-ray diffraction and mass spectrometric techniques. It was found that the powdered silicon obtained from magnesium reduction of RHA had a very low impurity concentration indicating that rice husk, which is an agricultural waste, is a potential source of metallurgical and solar-grade silicon.     

Structural,thermal, morphological and dynamic mechanical characteristics of waste‐reinforced polypropylene composites: A novel approach for recycling electronic waste

An in‐depth investigation has been carried toward utilizing polymer‐rich nonmetallic fraction of printed circuit boards (PCBs) as reinforcing fillers in polypropylene (PP) composites. The influence of waste additions (up to 25 wt %) on structural, thermal, morphological, and dynamic mechanical behavior of PP composites was investigated using a range of analytical techniques. The incorporation of PCB waste was found to affect the crystalline morphology resulting in the formation of smaller spherulites. The presence of glass fibers in PCB waste promoted the formation of β‐crystal enhancing the mechanical properties of composites. Thermal analysis showed a maximum increase of ～15 °C in the crystallization onset temperature (T_co) suggesting the nucleating effect of the filler, a feature also supported by structural investigations. Polarized microscopy revealed a reduction in the spherulite size after 5 wt % PCB waste loading owing to the presence of large number of nucleation sites. The incorporation of waste also increased the thermal stability of composites increasing the final degradation temperature by up to 14 °C. Dynamic mechanical properties of PP/PCB waste composites were determined in the temperature range ?20 to 155 °C; a significant increase in the storage modulus further confirmed the reinforcing effect of waste additives. This investigation has shown that the nonmetallic fraction of PCB waste could be used as a cost‐effective reinforcing filler for PP, providing an environmental friendly route to utilize electronic waste in value‐added products. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43389.     

Recent trends in environmentally friendly water-borne polyurethane coatings: A review

Environmentally friendly waterborne polyurethane (WPU) coatings are used extensively due to their low VOCs emission than solvent based PU coatings. Additionally, WPU coatings have low temperature flexibility, pH stability, water resistance, superior solvent resistance, outstanding weathering resistance and desirable chemical and mechanical properties. This review provides an overview on the recent developments of WPU coatings and their value added applications in the coatings and paint industry. UV-cured WPU coatings provide an important class of green and ecofriendly coatings with outstanding mechanical properties and rapid curing system. Hyper-branched polyurethanes (PUs) show interesting properties, such as high solubility, reactivity and good rheological behavior owing to multiple end groups, compact molecular structure and diminishing chain entanglement. Inherently, WPU coatings have reduced stiffness and mechanical strength that can be increased by the addition of nanoparticles, like Ag, Cu, TiO₂, SiO₂ and many more. Fire retardants, commonly phosphorous, are incorporated in the WPU structure to increase the flame retardancy of WPU coatings.     

Anticoagulant activities of goby muscle protein hydrolysates

The anticoagulant activities of protein hydrolysates prepared from goby muscle by treatment with various bacterial alkaline proteases were investigated. All proteases exhibited varying degrees of hydrolysis (DH) and all goby protein hydrolysates (GPHs) caused a significant prolongation of both the thrombin time (TT) and the activated partial thromboplastin time (APTT). The hydrolysate generated by the crude protease from Bacillus licheniformis NH1 displayed the highest anticoagulant activity, and the higher TT (about 32 s) at a concentration of 5 mg/mL was obtained with hydrolysate having a DH of 8.86%. This hydrolysate was then fractionated by size exclusion chromatography on a Sephadex G-25 column into five major fractions (F1–F5). Fraction F2, which exhibited the highest anticoagulant activity, was then fractionated by reversed-phase high-performance liquid chromatography. The molecular masses and amino acid sequences of four peptides in peptide sub-fraction F2–6, which exhibited the highest anticoagulant activity, were determined using ESI-MS and ESI-MS/MS, respectively. The structures of these peptides were identified as Leu-Cys-Arg, His-Cys-Phe, Cys-Leu-Cys-Arg and Leu-Cys-Arg-Arg.     

Physicochemical studies of crosslinked thiolated polyvinyl alcohol hydrogels

This study is related to the post-crosslinking of thiolated polyvinyl alcohol (TPVA) hydrogels using three crosslinkers, sodium trimetaphosphate (STMP), boric acid (BA) and glyoxal (GLY) under alkaline conditions. The crosslinking reaction was carried out under different conditions: crosslinker nature, crosslinker content and crosslinking time. The influence of different crosslinkers on the physicochemical and structural characteristics of TPVA was evaluated. The three reagents used for crosslinking presented different action mode on hydrogels. The optimized crosslinking conditions were the crosslinker content is 0.1 % (w/v) at crosslinking time of 30 min. The results showed that the STMP-crosslinked TPVA had the maximum thiol content and swelling ability. All crosslinked TPVA samples were stable in different pH media. The involvement of thiol and other relevant groups after crosslinking in the different crosslinked TPVA samples was confirmed by attenuated total reflectance-infrared spectra. The microanalysis of elements present in the crosslinked samples were analyzed by energy-dispersive X-ray microanalysis.     

In situ-based assessment of soil liquefaction potential–Case study of an earth dam in Tunisia

The present paper examines the evaluation of liquefaction potential of an earth dam foundation in Tunisia. The assessment of soil liquefaction was made using deterministic and probabilistic simplified procedures developed from several case histories. The data collected from the field investigation performed before and after the vibrocompaction are analyzed and the results are reported. The obtained results show that after vibrocompaction, a significant improvement of the soil resistance reduces the liquefaction potential of the sandy foundation. Indeed, in the untreated layers, the factor of safety FS drops below 1 which means that the soil is susceptible for liquefaction. However, in the compacted horizons, the values of FS exceed the unit which justifies the absence of liquefaction hazard of the foundation.     

Biallelic Variants in EPHA2 Identified in Three Large Inbred Families with Early-Onset Cataract

Hereditary congenital cataract (HCC) is clinically and genetically heterogeneous. We investigated HCC that segregates in three inbred families (LUCC03, LUCC16, and LUCC24). Ophthalmological examinations revealed cataracts with variability related to the age of onset segregating in a recessive manner in these families. Exome sequencing of probands identified a novel homozygous c.2710delG;p.(Val904Cysfs*36) EPHA2 variant in LUCC03 and a known homozygous c.2353G>A;p.(Ala785Thr) EPHA2 variant in the other two recessive families. EPHA2 encodes a transmembrane tyrosine kinase receptor, which is primarily involved in membrane-transport, cell-cell adhesion, and repulsion signaling processes. Computational structural modeling predicts that substitution of a threonine for an alanine p.(Ala785Thr) results in the formation of three new hydrogen bonds with the neighboring residues, which causes misfolding of EPHA2 in both scenarios. Insights from our study will facilitate counseling regarding the molecular and phenotypic landscape of EPHA2-related HCC.