Investigation of physicochemical and electronic properties of polyethylene oxide (PEO) and polyvinylpyrrolidone (PVP) blended solid polymer electrolyte incorporated with sodium perchlorate (NaClO
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) ...as ion-conducting species has been carried out using first-principle Study. A proficient approach is proposed to analyse the conductive mechanism of electrolytes, based on density functional theory. Density of states (DOS) and projected density of states (PDOS) analysis provides a quantitative explanation of the electronic bandgap of the polymer–polymer (PEO-PVP) and polymer–salt (PEO-PVP-NaClO
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) system. The bonding characteristic and charge distributions determined by charge density plot and crystal orbital overlap population analysis show to have a strong qualitative correlation with the ionic conductivity in solid polymer electrolyte.
ABSTRACT
We investigate the observational properties of a hydrogen-deficient superluminous supernova (SLSN) SN 2020ank (at z = 0.2485), with the help of early phase observations carried out between ...–21 and +52 d since g-band maximum. Photometrically, SN 2020ank is one of the brightest SLSN ($M_{\mathrm{ g,peak}}\, \sim$ –21.84 ± 0.10 mag), having fast pre-peak rising and post-peak decaying rates. The bolometric light curve of SN 2020ank exhibits a higher peak luminosity (Lmax) of ∼ (3.9 ± 0.7) × 1044 erg s−1 and appears to be symmetric around the peak with $L^{\mathrm{ rise}}_{\mathrm{ max}}$/e ${\approx}L^{\mathrm{ fall}}_{\mathrm{ max}}$/e ≈ 15 d. The semi-analytical light-curve modelling using the minim code suggests a spin-down millisecond magnetar with $P_i\, \sim$ 2.2 ± 0.5 ms and $B\, \sim$ (2.9 ± 0.1) $\times \, 10^{14}$ G as a possible powering source for SN 2020ank. The possible magnetar origin and excess ultraviolet flux at early epochs indicate a central-engine based powering source for SN 2020ank. Near-peak spectra of SN 2020ank are enriched with the W-shaped O ii features but with the weaker signatures of C ii and Fe iii. Using the estimated rise time of ∼ 27.9 d and the photospheric velocity of ∼ 12 050 km s−1, we constrain the ejecta mass to ∼ 7.2 M⊙ and the kinetic energy of ∼6.3 × 1051 erg. The near-peak spectrum of SN 2020ank exhibits a close spectral resemblance with that of fast-evolving SN 2010gx. The absorption features of SN 2020ank are blueshifted compared to Gaia16apd, suggesting a higher expansion velocity. The spectral similarity with SN 2010gx and comparatively faster spectral evolution than PTF12dam (a slow-evolving SLSN) indicate the fast-evolving behaviour of SN 2020ank.
The properties of surface waves in the partially ionized, incompressible magnetized plasma slab are investigated in the present work. The waves are affected by the non-ideal magnetohydrodynamic (MHD) ...effects which cause the finite drift of the magnetic field in the medium. When the finite drift of the magnetic field is ignored, the characteristics of the wave propagation in the partially ionized plasma fluid are similar to the ideal MHD, except now the propagation properties depend on the fractional ionization of the medium. In the presence of the Hall diffusion, the propagation of the sausage and kink surface waves depends on the level of fractional ionization of the medium. For example, short wavelength surface modes cannot propagate in the medium if the scale over which Hall operates is comparable to the size of the plasma slab. With the increasing ionization, the surface modes of shorter wavelength are permitted in the system. When both the Hall and Pedersen diffusion are present in the medium, the waves undergo damping. In the case of Pedersen dominating Hall, the damping of the long wavelength fluctuations is dependent on the ratio of the plasma densities inside and outside the slab and on the square of the Pedersen diffusivity. For typical solar parameters, waves may damp over few minutes.
Nickel–metal hydride (Ni–MH) batteries which generally contain nearly 55–60% Ni and 4–6% Co along with a few other metals may be considered an important resource for recycling and supply of these ...metals. In this study, leaching kinetics of nickel and cobalt, and other base metals from the spent Ni–MH batteries in sulfuric acid solutions have been investigated with an emphasis on the process characterization at different stages of the treatment. The maximum dissolution of nickel, cobalt, iron, manganese and zinc was found to be 91.6, 97.8, 65.5, 93.5 and 99.2%, respectively in a single stage under the optimum conditions comprising of 2M H2SO4, 100g/L pulp density and 348K temperature after 120min of leaching. Kinetic data for the dissolution of all the metals including the rare earths (as a group) showed the best fit to the chemical control shrinking core model. The activation energy of 8.7, 6.8, 7.12, 6.7 and 7.9kJ/mol was determined for the leaching of base metals viz., nickel, cobalt, iron, manganese and zinc, respectively in the temperature range 305–348K. With the help of the XRD phase analysis and the change in morphological features along with the elemental mapping in the leach residues with time and the untreated electrode material by SEM-EDS, the leaching mechanism was established. The process characterization corroborated the kinetic model for the leaching of metals which progressed through the chemical reaction of the lixiviant on the surface of the spherical particles of electrode powder. The XRD analysis of the residue showed the presence of metallic nickel which required stringent conditions for improved recovery of this metal.
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•Studied H2SO4 leaching of metals from electrode material of spent Ni–MH batteries•Most suitable conditions: 2M H2SO4, 100g/L pulp density, 348K, and 120min•Achieved leach recoveries of 91.6% Ni, 97.8% Co, 65.5% Fe, 93.5% Mn & 99.2% Zn•Leaching kinetics followed chemical control shrinking core model.•Process characterization confirmed surface reaction controlled leaching mechanism.
This study examines the energy requirement and energy input–output relationship of colocasia-based cropping systems viz., Colocasia–onion–frenchbean, colocasia–gardenpea–frenchbean, ...colocasia–wheat–okra, colocasia–radish–potato, colocasia–cabbage–frenchbean, colocasia–coriander–cauliflower–frenchbean, colocasia–corinder–tomato and rice–wheat in the Indian Himalayas. Results revealed that potato consumed the highest total input energy (25084 MJ/ha) and the least was in coriander (5108 MJ/ha). System productivity in terms of colocasia equivalent yield was highest with colocasia–onion–frenchbean system (52.38 t/ha). Mineral fertilizers (50–62%), seed (8–26%) and irrigation water (11–17%) consumed the bulk of the input energy for all cropping systems. The total input energy was highest under colocasia–radish–potato (59919 MJ/ha) and the lowest in rice–wheat (38244 MJ/ha). Colocasia–onion–frenchbean, with the highest system productivity, produced the highest energy productivity (1.203 kg/MJ). Colocasia–coriander–tomato, with the highest system biomass, produced higher energy ratio (30.4), human energy profitability (2813.4) and energy profitability (29.43). Colocasia–wheat–okra (1362928 MJ/ha) recorded the highest total energy output. Human energy profitability was highest under colocasia–coriander–tomato (2813.4) indicating that it was the most labor energy efficient cropping system. Hence, the colocasia–corinder–tomato and colocasia–onion–frenchbean cropping systems are more suitable in the Indian Himalayas for their higher energy use efficiency and energy productivity, respectively, and are advised for wide adoption.
Abstract
Nepal is seeking carbon-free alternative fuels due to environmental concerns and economic issues resulting from fossil fuel usage. Carbon-neutral SNG has the potential as an alternative to ...LPG gas in domestic cooking, but traditional LPG equipment may not be compatible with SNG. Computational Fluid Dynamics (CFD) was used to study the compatibility of traditional LPG equipment with SNG, and it was found that essential optimization is needed to obtain optimal cooking conditions by SNG combustion. Engineering Equation Solver (EES) was used to determine the optimum inlet pressure for varying nozzle sizes. Based on the results of the study, it was determined that the optimal nozzle size for the selected type of burner is 1.15 mm. This particular nozzle size was found to provide better uniformity of flame temperature and complete combustion, resulting in an average temperature of 1700 K at a fuel inlet pressure of 2.75 kPa. This makes it a potentially better option for cooking compared to LPG, as it could potentially provide faster cooking times. The results were verified using the Python CANTERA model. A 40-50% increase in the nozzle orifice size from the traditional LPG nozzle orifice size is suggested for such conversions.
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•Novel pH sensitive surfactant-stabilized Fe3O4 nanocarriers were developed.•Nanocarriers are water-dispersible, non-toxic and protein resistant in nature.•Capable of simultaneous ...loading of hydrophilic and hydrophobic anticancer agents.•Possess potential therapeutic efficacy upon conjugated with anticancer drugs.•Nanocarriers also show excellent heating efficacy under AC magnetic field.
Highly water-dispersible surfactant-stabilized Fe3O4 magnetic nanocarriers (SMNCs) were prepared by self-assembly of anionic surfactant, sodium dodecyl sulphate (SDS) on hydrophobic (oleic acid coated) nanoparticles and their biomedical applications were investigated. These nanocarriers have an average size of about 10nm and possess tunable surface charge properties. The formation of an organic coating of SDS was evident from infrared spectroscopy, dynamic light scattering, zeta-potential and thermogravimetric measurements. These nanocarriers were used for loading of both hydrophilic and hydrophobic anticancer agents such as doxorubicin hydrochloride (DOX) and curcumin (CUR), respectively. DOX was conjugated onto the surface of nanocarriers through electrostatic interaction, whereas CUR was encapsulated into the hydrophobic interlayer between oleic acid and SDS. The toxicity and cellular internalization of drug loaded nanocarriers were investigated against WEHI-164 cancer cell line. Specifically, the drug loading, pH sensitive drug release and cellular internalization studies suggested that these nanocarriers are suitable for dual drug delivery. Furthermore, they show good heating ability under AC magnetic field, thus can be used as effective heating source for hyperthermia treatment of cancer.
The presence of dust grains profoundly affects the diffusion of the magnetic field in molecular clouds. When the electrons and ions are well coupled to the magnetic field and charged grains are only ...indirectly coupled, emergent Hall diffusion may dominate over all the other non-ideal magnetohydrodynamic (MHD) effects in a partially ionized dusty cloud. The low-frequency, long (∼0.01-1 pc) wavelength dispersive MHD waves will propagate in such a medium with the polarization of the waves determined by the dust charge density or the dust size distribution. In the presence of shear flows, these waves may become Kelvin-Helmholtz unstable with the dust charge density or the grain size distribution operating as a switch to the instability. When Hall diffusion time is long (compared to the time over which waves are sheared), the growth rate of the instability in the presence of sub-Alfvénic flow increases with the charge number on the grain, while it is quenched in the presence of Alfvénic or super-Alfvénic flows. However, when Hall diffusion is fast, the growth rate of the instability depends on the dust charge only indirectly.
ABSTRACT
We present radio and optical afterglow observations of the TeV-bright long gamma-ray burst 190114C at a redshift of z = 0.425, which was detected by the Major Atmospheric Gamma Imaging ...Cherenkov telescope. Our observations with Atacama Large Millimeter/submillitmeter Array, Australia Telescope Compact Array, and upgraded Giant Metre-wave Radio Telescope were obtained by our low frequency observing campaign and range from ∼1 to ∼140 d after the burst and the optical observations were done with three optical telescopes spanning up to ∼25 d after the burst. Long-term radio/mm observations reveal the complex nature of the afterglow, which does not follow the spectral and temporal closure relations expected from the standard afterglow model. We find that the microphysical parameters of the external forward shock, representing the share of shock-created energy in the non-thermal electron population and magnetic field, are evolving with time. The inferred kinetic energy in the blast-wave depends strongly on the assumed ambient medium density profile, with a constant density medium demanding almost an order of magnitude higher energy than in the prompt emission, while a stellar wind-driven medium requires approximately the same amount energy as in prompt emission.
We present a multiwavelength study of the radio-loud narrow-line Seyfert 1 galaxy (NLSy1) 1H 0323+342, detected by the Fermi Gamma-Ray Space Telescope. Multiband light curves show many orphan X-ray ...and optical flares having no corresponding gamma-ray counterparts. Such anomalous variability behavior can be due to different locations of the emission region from the central source. During a large flare, a gamma-ray flux doubling timescale as small as ~3 hr is noticed. We built spectral energy distributions (SEDs) during different activity states and modeled them using a one-zone leptonic model. The shape of the optical/UV component of the SEDs is dominated by accretion disk emission in all the activity states. In the X-ray band, significant thermal emission from the hot corona is inferred during quiescent and first flaring states; however, during subsequent flares, the nonthermal jet component dominates. The gamma-ray emission in all the states can be well explained by inverse-Compton scattering of accretion disk photons reprocessed by the broad-line region. The source showed violent intra-night optical variability, coinciding with one of the high gamma-ray activity states. An analysis of the overall X-ray spectrum fitted with an absorbed power-law plus relativistic reflection component hints at the presence of an Fe Kalpha line and returns a high black hole spin value of a = 0.96 + or - 0.14. We argue that 1H 0323+342 possesses dual characteristics, akin to both flat-spectrum radio quasars (FSRQs) and radio-quiet NLSy1 galaxies, though at a low jet power regime compared to powerful FSRQs.
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