Numerical study of lap joints with composite adhesives and composite adherends subjected to in-plane and transverse loads

In this paper, single lap joints for joining fibre composites were modeled and a three-dimensional finite element method was used to study the joint strength under in-plane tensile and out-of-plane loadings. The behaviour of all the members was assumed to be linear elastic. The adherends were considered to be orthotropic materials while the adhesive could be neat resin or reinforced one. The largest values of shear and peel stresses occurred near the ends of the adhesive region, as expected. The values and the rate of variation in peel stress was more than that of shear stress. By changing the properties and behaviour of adhesive from neat epoxy (isotropic) to fibre composite adhesive (orthotropic) and with various fibre volume fractions of glass fibre, the ultimate bond strength increased as the fibre volume fraction increased, in both tensile and transverse loadings. Also, changing the orientation of fibres in the adhesive region with respect to the global axes influenced the bond strength.     

Fast mass and charge transport through electrically aligned CNT/polymer nanocomposite membranes

This work represents the properties of electrically aligned carbon nanotubes (CNT)/polycarbonate (PC) nanocomposites towards the development of hydrogen gas separation membranes. A fraction (0.1 weight %) of CNTs synthesized by chemical vapour deposition method have been dispersed homogeneously throughout PC matrix by ultrasonication. The alignment of CNT in PC matrix has been accomplished by applying an external electric field of 1250 V/cm during solution casting. These nanocomposites have been studied by gas permeation, electrical, and dielectric constant measurements. Gas permeability measurements obtained here that electrically aligned nanocomposite membranes can be used as good hydrogen separating media. I–V characteristics and dielectric constant shows the enhancement in conductivity and permittivity of these nanocomposites. Overall experimental results exhibit here that alignment of CNTs in polymer matrix shows the dramatic improvement in mass and charge transport properties. Copyright © 2016 John Wiley & Sons, Ltd.     

Integrated Assessment of no-Regret Climate Change Adaptation Options for Reservoir Catchment and Command Areas

The need for credible, salient and legitimate climate change adaptation options in the water sector, which target location specific adaptation requirements, is well recognized. In developing countries, the low-hanging fruit; no-regret options, should be identified with stakeholders and assessed against future changes in water availability and demand, for comparing effectiveness and robustness. Such integrated basin-scale assessments, including reservoir catchment and command areas, can suitably inform adaptation decision-making. In this study, we integrate participatory and modelling approaches for evaluation of reservoir catchment and command area no-regret options addressing water availability and demand in the Kangsabati river basin. Through multi-level stakeholder workshops we identify and prioritize options, followed by evaluation of two reservoir catchment options; check dams and increasing forest cover and three reservoir command options; changing cropping pattern, traditional ponds and waste water reuse, using the Water Evaluation And Planning (WEAP) model. We use four high resolution (~25 km) regional climate model simulations of future climatic factors, along with non-climatic factors affecting water demand, for forcing WEAP. We find that options have varied ability in addressing adaptation requirements. Amongst catchment options, increasing forest cover addresses adaptation requirements more suitably than check dams, while in the command areas we observe mixed abilities of options, leading to the inference that combining complementary options may be a more useful strategy. We conclude by discussing our experiences with this approach in a developing country context, in terms of benefits, limitations, lessons learnt and future research directions.     

Extracellular synthesis of silver nanoparticles using dried leaves of pongamia pinnata (L) pierre

Nano-Micro Letters - Extract of oven dried leaves of Pongamia pinnata (L) Pierre was used for the synthesis of silver nanoparticles. Stable and crystalline silver nanoparticles were formed by the...     

Superplasticity in intermetallic NiAl nanowires via atomistic simulations

A novel superplastic deformation in an intermetallic B2-NiAl nanowire of cross-sectional dimensions of ∼ 20 Å with failure strain as high as ∼ 700% at 700 K temperature is reported. The minimum temperature under which the superplasticity has been observed is around 0.36 T_m, which is much lower than 0.5 T_m (T_m = melting temperature i.e. 1911 K for bulk B2-NiAl). Superplasticity is observed due to transformation from crystalline phase to amorphous phase after yielding of the nanowire.     

Bio‐polyester–date seed powder composites: Morphology and component migration

Biodegradable polyesters poly‐l ‐lactide (PLA) and poly(butylene adipate‐co‐terephthalate) (PBAT) were reinforced with varying amount of date seed powder (DSP) with an aim to utilize the date seed waste as well as to achieve composites with improved properties. The PLA composites exhibited increase in the elastic response over the viscous response as a function of filler fraction, whereas the PBAT composites retained the viscous dominance irrespective of DSP content. The tensile modulus of the PBAT composites had enhancement of more than 300% in the composite with 40% filler content. The PLA composites also enhanced the modulus marginally till 20% filler content, however, it was still significant because of the very high modulus of PLA as compared to PBAT. Thermal analysis also indicated the stability of the composite, thus, confirming the usefulness of DSP as filler for the polymers. The TEM and light microscopy characterization revealed presence of voids in the composites which were present around the filler particles as well as dispersed in the polymer matrix. Such features were confirmed through TGA‐MS to be resulting from the escape of water vapor bound in DSP. The composites with 10% DSP content had lower extent of such voids and the morphology remained relatively unchanged with time. In the composites with 30% DSP content, in the seasoned sample, a soft and sticky phase resulting from the surface migration of date seed oil was also observed. The generation of the soft phase was also a slow process as 24 h were not enough to generate this phase. The migration of the oil to the surface was also confirmed by the IR and X‐ray diffraction studies. After embedding in compost soil, the PLA composite with 40% filler content had nine times more biodegradation after 120 days as compared to pure polymer, whereas it was 11 times for PBAT composite with same filler content. It confirmed that the addition of DSP did not lead to any thermal and mechanical degradation of the bio‐polyesters and resulted in enhanced mechanical and biodegradation behavior along with oil migration. The controlled component migration can lead to potential generation of commercially important self‐lubricating composite materials. POLYM. ENG. SCI., 55:877–888, 2015. © 2014 Society of Plastics Engineers     

Temperature-enhanced alumina HPLC method for the analysis of wax esters,sterol esters,and methyl esters

Previous attempts at separating nonpolar lipid esters (including wax esters, sterol esters, and methyl esters) have achieved only limited success. Among the several normal-phase methods tested, a single recent report of a method employing an alumina column at 30°C with a binary gradient system was the most promising. In the current study, modification of the alumina method by increasing the column temperature to 75°C improved the separation of standards of wax esters and sterol esters. Elevated column temperature also enhanced the separation of FAME with differing degrees of unsaturation. Evidence was also presented to indicate that the method similarly separated phytosterol esters, based on their levels of unsaturation. With the increased interest in phytosterol- and phytostanol esterenriched functional foods, this method should provide a technique to characterize and compare these products.