Surface-modified polyacrylonitrile nanofibers as supports

Polyacrylonitrile nanofibers (PAN-nfs) are one of the most studied nanofibres because of their excellent characteristics, such as good mechanical strength, chemical resistance, and good thermal stability. Due to the easy dissolution in polar organic solvents, PAN-nfs are mostly produced via electrospinning technique. The electrospun PAN-nfs surfaces are relatively in-active and hydrophobic, and, therefore, hinder some potential applications; however, chemical surface modification reactions, such as amination, reduction, hydrolysis, and amidoximation, have been carried out on them. These reactions bring about functional groups, such as amine, hydroxyl, carboxylic, imine etc, to the surface PAN-nfs and invariably make their surfaces active and hydrophilic. The surface-modified PAN-nfs have been used as supports for organic compounds, enzymes, and antibodies in biological studies. They have also been used for immobilization of various organic ligands for adsorption of metal ions in water. Furthermore, because of their ability to complex metal ions, several surface-modified PAN-nfs have also been used as supports for transition metal catalysts in Fenton’s chemistry.IS

Supervised Learning System for Pest Disease Identification and Recommendations using Wireless Sensor Network in Agriculture Domain

Designing wireless sensor networks (WSNs) that will sustain for longer time have been a challenging issue. For achieving this, efficient utilization of available energy should be anticipated from energy-constrained sensors running autonomously for long periods. In the field of agricultural research, farming related activities, assistance to farmers using advanced IoT and sensor network technologies is a need of time. Initially this paper briefed about smartphone based application systems that forewarns the farmer about pests/diseases that can occur on the crop. The designed system assists farmers to foresee the crop disease using machine learning algorithm. The disease can be predicted based on the environmental parameters as soil moisture, temperature and humidity obtained from sensor node and other parameters like rain fall, evaporation rate and sun shine hour obtained from open weather map application programming interfaces. A prototype is developed using ultra low powered micro-controller with interconnected sensor’s module. While comparing with the Arduino micro-controller based system, it was observed that the developed prototype system utilized less energy with effectively forewarned the farmers about crop diseases using Internet of Things (IoT). Thus it would assist the farmers proactively to reduce the losses due to crop diseases.</jats:p

Dielectric Relaxation and Hydration Interactions for Protic and Aprotic Ionic Liquids using Time Domain Reflectometry

H-Bonding abilities of ionic liquids (ILs) along with hydrophobicity and cooperativity effects increases their hydration numbers making them capable for dissolving sparingly soluble organic molecules in aqueous or polar nonaqueous media, and hence ILs are potential candidates in pharmaceutical and medicinal sciences besides the different technological and academic interests. In this work, dielectric spectra were measured and analyzed for diethylammonium-based protic ionic liquids (PILs), imidazolium-based aprotic ionic liquids (APILs), and their aqueous solutions (∼0.02 to ∼0.8 mol·dm–3) over a frequency range from 0.01 to 50 GHz using time domain reflectometry at 298.15 K. The Cole–Cole (CC) model for neat ILs and a combination of the Debye and Cole–Cole (D+CC) models for their aqueous solutions best describes the experimental dielectric relaxation spectra. Higher values of static permittivity and relaxation time were observed for less viscous PILs compared to more viscous APILs due to the existence of hydrogen bonding in PILs, ionic translational motion, and the existence of transient, short-lived proton transfer responsible for solvent polarization. For aqueous solutions of ionic liquids, the fast collective relaxation of solvent (bulk water) observed at higher frequencies (∼20 GHz) and slow relaxation is detected at lower frequency (∼5 to ∼10 GHz) due to hydrophobic hydration with or without cooperative H-bonding effect. The apparent concentrations of bulk water, cbwap, and slow water, cswap, were used to obtain effective hydration numbers to understand the ion solvation. Hydration numbers revealed that imidazolium-based APILs are weakly hydrated than the diethylammonium-based PILs. Static permittivity and relaxation time of pure ILs and of aqueous solutions of studied ILs are discussed in terms of effect on alkyl chain length of cation/anion, H-bonding abilities of ions, dipole moments of ions, viscosity, hydrophobic effects, etc