The production of various plastic wastes is increasing day by day and has become a growing concern to the serious environmental challenges. This type of waste is rarely resolved by microorganisms; hence, the recycling to the value-added materials is essential. In recent years, superhydrophobic surfaces have gained increasing attention in both fundamental research and practical applications due to multi-functionalities. Recycling the polymer wastes for the fabrication of superhydrophobic nanofibers could be a partial solution to environmental issues. The superhydrophobic surfaces can be fabricated by controlling the chemical composition and topological structure using various methods. In this work, recycled expanded polystyrene (EPS) foam with various proportions of titanium dioxide nanoparticles (TiO₂ NPs) and aluminum microparticles (Al µPs) was spun into superhydrophobic nanocomposite fibers using the facile electrospinning technique. The morphology, surface hydrophobicity, and thermal properties of the nanocomposite fibers were investigated. Test results showed that the as-prepared nanocomposite fibers exhibit superhydrophobic characteristics with a water contact angle of 152°. Also, the effect of heat treatment on the surface hydrophobicity of the nanocomposite fibers was analyzed. The electrospun superhydrophobic nanocomposite fibers from recycled EPS foam have various industrial applications, including water collection, water filtration, tissue engineering, and composites.

In this paper, we have investigated a three-species food web model consisting of two preys and one predator with the assumption that in the presence of predator both teams of prey help each other. The interaction between second prey and predator is assumed as a Holling type I (Volterra) functional response because in the absence of any predation, the second prey grows unboundedly following Malthusian law. The relationship between the Canada lynx (Lynx canadensis) and the snowshoe hare (Lepus americanus) can be considered (in good agreement with our model) as an example of how interaction between a predator and its second prey can influence population dynamics. On the other hand, a modified Holling type II functional response is considered to represent the interaction between first prey and predator incorporating the Malthusian law of growth for the second prey. Also, there is no inter-specific competition among the two-prey species as the second prey has sufficient resources. Moreover, it is assumed that there may be competition among the individuals of the predator species. Next, we have discussed the positivity of the solutions of the proposed system. In this work, we have studied about various types of equilibrium points and their stability behaviour. Also, transcritical bifurcations of the planer equilibrium points and persistent of system are discussed. The effect of discrete time delay (as gestation period) is analysed to observe the switching behaviour of the delay parameter. The maximum length of delay has been determined to preserve the stability of one-periodic limit cycle. Also, the direction, period and the stability of bifurcating periodic solutions have been examined based on normal form method and centre manifold theory. Numerical simulations are also performed to verify analytical findings.

Sustainable food production is one of the major challenges in this era of global environmental problems such as population pressure, natural resource degradation, biodiversity loss and climate change. Agriculture being one of the prime sectors that sustain livelihood of the farmers also contributes to climate change. In this context, traditional agriculture has proven its effectiveness, adaptability and resilience for sustainable food production in the changing climatic conditions. The bun agricultural practice of the Khasi and Jaintia tribes of Meghalaya in Northeast India based on traditional ecological knowledge (TEK) offers an interesting example of sustainable agriculture and food production. An overview of the traditional bun cultivation practices and its modifications adopted by the local people has been discussed in the present study. The data for this study were obtained through focus group discussions with the cultivators and interviewing key informants followed by field survey. The study revealed that farmers grow the crops under a completely rain fed condition and make use of limited biomass and land resources, organic fertilizers and pesticides, thereby making the system sustainable. In addition, the farmers also abandon the land for a period of one to three years to restore soil fertility. However, due to increase in population, growing food demand, limited land availability and the socio-economic condition of the farmers, the traditional bun cultivation has undergone a number of modifications. The modifications include changes in cropping pattern, choice of crop, pest management and fallow period management that adapt well to local climatic conditions with higher food production and economic benefits. Understanding the various modifications and their integration with traditional agricultural practices can potentially form the basis for a sustainable, economically viable, environmentally sound and resilient agricultural system.

In this work, we have introduced an ecological model of a prey–predator system. It is assumed that the prey species grows logistically, but the total number of predator is constant in the time interval. Positivity and boundedness of the solution ensure that the proposed model is well-posed. Local stability conditions of the equilibrium points have been analysed by the Routh–Hurwitz criterion. The persistence of the system has also been shown under a parametric restriction. Numerical analysis has indicated that both axial and interior steady states can exist only for moderate consumption rate (searching efficiency). But if this rate becomes high (or low), then only the prey-free equilibrium (or one of the interior equilibriums) exists as a steady state. Further, the equilibrium points can change their stability through transcritical and saddle-node bifurcations by varying the consumption rate of the predator. Analytical results provide an interesting phenomenon about this model: the system can never show any oscillating behaviour for any parametric values, i.e. no limit cycle can occur through Hopf bifurcation around an equilibrium point. The axial equilibrium becomes stable from an unstable situation when the consumption rate becomes high and the interior state which is stable remains stable as time goes by.

The copper, cobalt and nickel ores are still currently mined in the world. Its complex mineralogy creates extraction challenges by means of conventional metallurgical methods. Meanwhile, dealing with mesophilic strains in leaching process requires a compromise between solid loading and microbiota activity and growth. That is why, the influence of solid loading with fine or coarse particulates, the cell disturbance during the metal–microbes interactions depending upon the influence of gangue nature as well as metallic ions concentration on bacterial tolerance and the chemical and biological pathways involved in bioleaching mechanism of complex ores are summarised in detail in this paper. The current trends in mechanism research and diverse discovered set of microbiota and bacterial population coupled with bacterial adaptation methods contribute to optimise and improve the metals leaching performance and knowledge. In addition, the different existing complex mineralogical structures elaborate a main indirect mechanism with two different transitory mechanisms, before metal is converted into metal sulphate as wealthily explained in this comprehensive review. More data for cost analysis concomitant with extraction efficiency of metals using mesophilic bioleaching process are needed. However, it does not mean that other options are excluded in order to set a bio-hydrometallurgical chain. In fact, to consider also the concentration and purification of the pregnant leaching solution via phase separation and solvent extraction will be helpful. This obeys to the idea of option trees, where possible options are then systematically gaged with respect to critical criteria.