In the present work we have studied a prey-predator model with logistic growth of the prey in the absence of the predator. We have also considered the fear effect and have investigated the impact of ...fear of the predator on prey when the predator is provided additional food. Functional responses of the predator towards prey and additional food are derived in this text. Death rates of both prey and predator have been considered as stochastic parameters due to the effect of the fluctuating environment. Existence and uniqueness, boundedness and uniform continuity of the global positive solution of the proposed model have been established. The conditions for extinction and persistence of the system have been derived. In the investigation, it is found that environmental noise plays a vital role in extinction as well as in persistence. Our analytical derivations are justified through numerical simulations which show the reliability of the model from the ecological point of view. We have also investigated the impact of intense fear as well as the absence of fear on this model by numerical simulation. Several interesting numerical results have been obtained based on different fear functions.
We synthesised a polyaniline/mica (Mica-PANI) nanocomposite using naturally occurring muscovite mica by a top-down approach. The developed coating materials were characterised using a different ...technique to investigate their chemical and structural properties using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). Furthermore, the electrochemical properties of the coating materials were investigated by linear sweep voltammetry (LSV). SEM images elucidate the composite's average particle diameter of the prepared nano-mica, approximately 80 nm. The existence of relevant functional groups and bonding in the prepared Mica-PANI composite material was confirmed by means of XPS and FTIR techniques. Moreover, the synthesised composite with 5% w/w shows high anticorrosion protection,
i.e.
84 μm per year, compared to competing materials, including commercial paint and individual raw materials (0.35 mm per year). The anti-corrosive effect occurs mainly due to two opposing effects: the formation of an Fe(OH)
3
passive layer on the steel surface by oxidation of surface iron atoms by the PANI and the barrier effect of mica NPs through inhibition of corrosive agents. Therefore, the eco-inspired composite could be an ideal cost-effective coating material to prevent the corrosion of mild steel surfaces.
We synthesised a polyaniline/mica (Mica-PANI) nanocomposite using naturally occurring muscovite mica by a top-down approach as an anticorrosive coating.
In this work, a fractional-order prey-predator system with fear effect of predator on prey population and group defense has been proposed. The existence and uniqueness of the system have been ...studied. Non-negativity and boundedness are also theoretically demonstrated. Analysis of local stability with examination of saddle-node and Hopf bifurcation at equilibrium points are performed by the help of numerical simulations along with analytical study. All the numerical simulations are performed using MATLAB and MAPLE.
Abstract
Li
3
YCl
6
is a promising candidate for solid electrolytes (SEs) in all-solid-state Li-ion batteries due to its high ionic conductivity, electrochemical stability, and compatibility with ...metal-oxide electrodes. The monoclinic and trigonal crystal structures of Li
3
YCl
6
with space groups C2/c and P-3m1 have been studied extensively, while little attention has been given to the trigonal P-3c1 phase (space group no. 165). Additionally, Li-ion diffusion mechanism in 3d transition metal (TM) substituted compounds along with their structural stability are interesting to study. Therefore, we investigate the Li diffusion mechanism in Li
3
YCl
6
and TM substituted Li
3
YCl6 in the P-3c1 phase using first-principles calculations. We have found that all the substituted compounds are thermodynamically stable at room temperature and show high oxidation stability. Li
3
Y
0.875
Co
0.125
Cl
6
exhibits the lowest activation energy (0.11 eV) for Li-ion diffusion and the highest Li-ion mobility (
σ
= 0.39 mS cm
−1
at room temperature), which is strongly anisotropic. We used the Crystal Orbital Hamilton Population method to analyze the bonding characteristics of Li
3
YCl
6
and 3d TM substituted Li
3
YCl
6
and found that the Co–Cl bond is weaker than the Cr–Cl bond. This may explain the lower activation energy observed for Li
3
Y
0.875
Co
0.125
Cl
6
. Our results provide insights into the substitution effect in Li
3
YCl
6
superionic conductors, which could guide the design and development of high-performance SEs for Li-ion batteries.
Using first-principles density functional calculations, we show that a transition-metal (TM)-doped defected graphene sheet with periodic repetition of a C atom vacancy (Vc) can be used as a promising ...system for hydrogen storage. The TM atoms adsorbed above and below the defected site are found to have a strong bonding to the graphene sheet, thereby circumventing the problem of TM clustering, which is the main impediment for efficient hydrogen storage in nanostructure systems. The results reveal that, when the vacancy-modulated graphene sheet is decorated on both sides by a combination of less than half-filled (TM1) and more than half-filled (TM2) elements, it results in the adsorption of molecular hydrogen with a binding energy lying in the desirable energy window. Among all the different TM1−TM2 combinations at a C vacancy site, Fe−Ti turns out to be the best choice where five H2 molecules get attached on each pair. To underscore the stability of these hydrogenated systems, we have performed an ab initio molecular dynamics simulation for a fully decorated defected graphene structure. The results show that, at room temperature, the system is stable with a gravimetric efficiency of 5.1 wt % of hydrogen, whereas desorption starts only at ∼400 K.
First-principles density functional theory-based calculations have been performed to investigate the strain-induced modifications in the electronic and vibrational properties of monolayer (ML)-ZnO. A ...wide range of in-plane tensile and compressive strain along different directions are applied to analyse the modifications in detail. The electronic band gap decreases under both tensile and compressive strain, and a direct-to-indirect band gap transition occurs for high values of biaxial tensile strain. The relatively low rate of decrease of band gap and large required strain for direct-to-indirect band gap transition compared to other 2D materials are analysed. Systematic decrease in the frequency of the in-plane and increase in the out-of-plane optical phonon modes with increasing tensile strain are observed. The in-plane acoustic modes show linear dispersion for unstrained as well as strained cases. However, the out-of-plane acoustic mode (ZA), which shows quadratic dispersion in the unstrained condition, turns linear with strain. The dispersion of the ZA mode is analysed using the shell elasticity theory and the possibility of ripple formation with strain is analysed. The strain-induced linearity of the ZA mode indicates the absence of rippling under strain. Finally, the stability limit of ML-ZnO is investigated and found that for
18
%
biaxial tensile strain the structure shows instability with the emergence of imaginary phonon modes. Furthermore, the potential of ML-ZnO to be a good thermoelectric material is analysed in an intuitive way based on the calculated electronic and phononic properties. Our results, thus, not only highlight the significance of strain-engineering in tailoring the electronic and vibrational properties but also provide a thorough understanding of the lattice dynamics and mechanical strength of ML-ZnO.
Abstract Leguminous crop Tephrosia candida has high biomass production and contains a substantial quantity of nutrients within its biomass. Starting in 2019, a long-term study was done to find the ...best Tephrosia candida dose for mulching in guava orchards. The study had four treatments: T 1 = 3.0 kg dry biomass m −2 of the plant basin, T 2 = 2.0 kg, T 3 = 1.0 kg, and T 4 = control (no mulch). Every year, the treatments imposed in the month of August. The third year (2021–2022) results indicated that mulching with 3 kg of biomass m −2 increased trunk diameter, fruit yield, fruit weight, specific leaf area, total leaf chlorophyll, and leaf macro- and micro-nutrients. At 3.0 kg m −2 , mulching improved soil properties such as EC, available nitrogen, available phosphorus, exchangeable potassium, DTPA extractable micronutrients (Fe, Zn, Cu, and Mn), total organic carbon (C toc ), soil organic carbon (C soc ), organic carbon fractions, and microbial biomass carbon between 0–0.15 m and 0.15–0.30 m. There was an increasing trend in dehydrogenase activity (DHA) and fluorescein diacetate (FDA). The Tephrosia leaf litter exhibited decay constants of 1.27 year −1 , and the carbon content was 40.11%. Therefore, applying Tephrosia biomass mulching at a rate of 3.0 kg m −2 is a viable long-term solution for enhancing soil fertility and sequestering carbon.
A UV, visible and NIR range irradiation responsive magnetite/graphite nanoplatelets composite was successfully synthesised via a single-step facile in-situ electrochemical exfoliation method using ...natural vein graphite. The spectral analysis revealed that as-synthesised photocatalyst could rapidly degrade the organic dyes with 96.1, 78.0 and 82.6 % efficiency in 120 minutes under respective UV, Visible, and NIR ranges of the electromagnetic spectrum. The formation of the magnetite-graphite nanoplatelet (GNP) nanocomposite was verified with X-ray diffraction (XRD), Fourier transform infrared absorption spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) analysis. The scaffold of highly electrically conductive GNP helps magnetite nanoparticles for the efficient distribution of photoinduced electrons generated by the photocatalytic activity to participate in the photodegradation of organic dyes, through rapid superoxide radical formation. The current work presents a hypothesized mechanism for the photocatalyst composite synthesis, while a thorough discussion was made on the improvements in photocatalytic degradation kinetics under multiple irradiation conditions through the synergy of the magnetite and GNP. High efficiency, low-cost facile synthesis, easy up scalability, and the easy removal of the catalyst as needed via an external magnetic field can be identified as major benefits of as-synthesised green catalyst, which can be readily used in dye pollutant removal and wastewater treatment applications.
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