Electrospun Piezoelectric Polymer Nanofiber Layers for Enabling in Situ Measurement in High-Performance Composite Laminates

This article highlights the effects from composite manufacturing parameters on fiber-reinforced composite laminates modified with layers of piezoelectric thermoplastic nanofibers and a conductive electrode layer. Such modifications have been used for enabling in situ deformation measurement in high-performance aerospace and renewable energy composites. Procedures for manufacturing high-performance composites are well-known and standardized. However, this does not imply that modifications via addition of functional layers (e.g., piezoelectric nanofibers) while following the same manufacturing procedures can lead to a successful multifunctional composite structure (e.g., for enabling in situ measurement). This article challenges success of internal embedment of piezoelectric nanofibers in standard manufacturing of high-performance composites via relying on composite process specifications and parameters only. It highlights that the process parameters must be revised for manufacturing of multifunctional composites. Several methods have been used to lay up and manufacture composites such as electrospinning the thermoplastic nanofibers, processing an inter digital electrode (IDE) made by conductive epoxy-graphene resin, and prepreg autoclave manufacturing aerospace grade laminates. The purpose of fabrication of IDE was to use a resin type (HexFlow RTM6) for the conductive layer similar to that used for the composite. Thereby, material mismatch is avoided and the structural integrity is sustained via mitigation of downgrading effects on the interlaminar properties. X-ray diffraction, Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, and scanning electron microscopy analyses have been carried out in the material characterization phase. Pulsed thermography and ultrasonic C-scanning were used for the localization of conductive resin embedded within the composite laminates. This study also provides recommendations for enabling internally embedded piezoelectricity (and thus health-monitoring capabilities) in high-performance composite laminates

Feeding behaviour and pugmark analysis of elephants in Sarguja, Chhattisgarh

The pugmark analysis of the elephants offers basic information to track the wild elephant migratory route, identification and census. For its study, four blocks viz, Sitapur, Lundra, Batouli (Sarguja district) and Farsabahar (Jashpur district) of northern Chhattisgarh were selected because these blocks are commonly visited by elephants and a major path route of movement of heard in inter/intra state. The most commonly consumed species belongs to family poaceae (22.58%) followed by fabaceae (19.35%) but their diet was mainly dependent on availability of seasonal food round the year and on their migration. Elephants extensively fed on Artocarpus heterophyllus, Syzygium cumini, Acacia nilotica, A. catechu, Dalbergia sissoo, Zizyphus mauritiana, Aegle marmelos and Ficus species, besides these elephants also utilized various grasses and shrubs as their food, which mainly included Dendrocalamus strictus, Cynodon dactylon etc. Elephants sometimes spent long time to feed on some particular plant species like D. strictus and Ficus species. Crop raiding, which was sporadic during the rainy season, gradually increased with more area being cultivated with the onset of monsoon. Analysis of pugmark revealed that the circumference varied from 63.80 cm to 172.70 cm whereas length x width varied from 22x20 cm to 60x55 cm, which reflects a substantial variation/differentiation of individual in heard in respect of their age, sex, size etcTherefore, management implications are needed to conserve the corridors for their long term survival and reduction of HEC. The study will be helpful to provide key information and facilitate better understating of the scenario to the forest department, policy maker and conservationist to plan, manage and improve the habitat towards the restoration and afforestation of suitable palatable species preferred by elephants of northern corridors of Chhattisgarh

Socio-economic status of human-elephant conflict: Its assessment and solutions

The study was made to examine the effect of human-elephant conflict (HEC) on socio-economic vulnerability in corridors of northern Chhattisgarh. Incidents relating to conflicts were observed and analyzed to understand the socio-economic status of the people, their attitudes towards elephant, the way people and elephants were affected along with different aspects of conflicts. The records whatsoever available on HEC of forest department were also took into consideration during analysis. It was found that majority of respondents involved in farming besides other sources like livestock (63.0%), NTFPs collection (42.50%) etc. Paddy (57.50%) and sugarcane (40.0%) constitute major crops which likely favours the incidence of HEC in the region. Nearly 112 houses and 939.02 acre of crops were damaged along with 06 human deaths. It was found that 46% of the respondents respected the animal as a religious figure while 30% fear them and most of the respondents (77.50%) were in favour of compensation. This necessitated a detailed assessment of habitat suitability and dispersal corridor for elephants in the area. Therefore, an attempt has been made to present various aspects of HEC along with management implications

A Constitutive Modeling and Experimental Effect of Shock Wave on the Microstructural Sub-strengthening of Granular Copper

Micro-sized copper powder (99.95%; O≤0.3) has been shock-processed with explosives of high detonation velocities of the order of 7.5km/s to observe the structural and microstructural sub-strengthening. Axisymmetric shock-consolidation technique has been used to obtain conglomerates of granular Cu. The technique involves the cylindrical compaction system wherein the explosive-charge is in direct proximity with the powder whereas the other uses indirect shock pressure with die-plunger geometry. Numeric simulations have been performed on with Eulerian code dynamics. The simulated results show a good agreement with the experimental observation of detonation parameters like detonation velocity, pressure, particle velocity and shock pressure in the reactive media. A pin contactor method has been utilized to calculate the detonation pressure experimentally. Wide angled x-ray diffraction studies reveal that the crystalline structure (FCC) of the shocked specimen matches with the un-shocked specimen. Field emissive scanning electron microscopic examination of the compacted specimens show a good sub-structural strengthening and complement the theoretical considerations. Laser diffraction based particle size analyzer also points towards the reduced particle size of the shock-processed specimen under high detonation velocities. Micro-hardness tests conducted under variable loads of 0.1kg, 0.05kg and 0.025kg force with diamond indenter optical micrographs indicate a high order of micro-hardness of the order of 159Hv. Nitrogen pycnometry used for the density measurement of the compacts shows that a compacted density of the order of 99.3% theoretical mean density has been achieved

On the optical properties of Ag^{+15} ion-beam irradiated TiO_{2} and SnO_{2} thin films

The effects of 200-MeV Ag^{+15} ion irradiation on the optical properties of TiO_{2} and SnO_{2} thin films prepared by using the RF magnetron sputtering technique were investigated. These films were characterized by using UV-vis spectroscopy, and with increasing irradiation fluence, the transmittance for the TiO_{2} films was observed to increase systematically while that for SnO_{2} was observed to decrease. Absorption spectra of the irradiated samples showed minor changes in the indirect bandgap from 3.44 to 3.59 eV with increasing irradiation fluence for TiO_{2} while significant changes in the direct bandgap from 3.92 to 3.6 eV were observed for SnO_{2}. The observed modifications in the optical properties of both the TiO_{2} and the SnO_{2} systems with irradiation can be attributed to controlled structural disorder/defects in the system.Comment: 6 pages, ICAMD-201

Structural Parameters and Swelling Behavior of pH Sensitive Poly(acrylamide-co-acrylic acid) Hydrogels

In the present work, hydrogels based on acrylamide (AAm) and acrylic acid (AAc), crosslinked with N,N’-methylenebisacrylamide (MBAAm) were prepared by free radical polymerization in solution. The effect of initial AAm/AAc mole ratio and nominal crosslinking ratio (moles of crosslinking agent/moles of polymer repeat unit) on the dynamic and equilibrium swelling behaviour of hydrogels was investigated. Hydrogels were characterized by the polymer volume fraction in the swollen state (ν2,s ), the number average molecular mass between crosslinks (Mc ) and the mesh size (ξ). The swelling capacity of hydrogels was found to decrease with increasing nominal crosslinking ratio. The results show a significant influence of AAc monomer concentration on swelling behavior of poly(acrylamide-co-acrylic acid) hydrogels. Hydrogels containing higher acrylic acid content had a higher equilibrium mass swelling at pH 7.4 and in distilled water than at pH 3.0 where the acrylic acid is present in nonionized state. Further, swelling data was fitted to various models and model parameters were evaluated using regression technique. Model analysis indicated that the swelling transport followed non-Fickian mechanism. Scanning electron microscopy (SEM) revealed the macroporous surface morphology of the matrix with pore size varying between 2–64 microns depending on the amounts of AAc in the hydrogel