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The microstructure, tensile strength (TS), impact strength and hardness of Al-7Si-Mg alloy amalgamated with grain refiner (GR) Al-5Ti-B and modified by novel combination of modifiers K or/and CeO2have been examined in this study. The results demonstrated that the addition of 0.1% Al-5Ti-B grain refiner and 2 wt.% K and 0.5 wt.% CeO2improved the tensile strength, impact strength, and hardness of the Al-7Si-Mg alloy by 26.5%, 31%, and 18% as compared to those obtained for base alloy. The synergic effect of grain refiner, modifier(s), and heat treatment (HT) led to significant increment in tensile strength, impact strength, and hardness of the alloy. Tensile and impact test fractography microstructures revealed that the Al-7Si-Mg alloy containing grain refiner, 2 wt.% K and 0.5 wt.% CeO2exhibited a more dimpled structure, indicating its ductile nature.

This study investigates the Pleistocene–Holocene transition in Serra Leste, a highly endangered southeastern Amazonian ecotone, with a focus on the lake-filling process, climate changes, and potential consequences to forest and savanna dynamics. The lake's development began at approximately 14000 cal yr BP, resulting from the collapse of the fractured lateritic crust. Sedimentation patterns and geochemical, palynological and micro-charcoal proxies reveal shifts in detrital input and redox conditions, forest/savanna areas, and local and regional fire events, indicating a highly dynamic environmental history. The evolution of the lake is characterized by initial deltaic lobe deposition and forest dominance, followed in the Middle Holocene by sedimentary gaps or reduced detrital input; woody vegetation dominance, with a notable shift toward a more open landscape; and savanna and semideciduous dry forest, accompanied by a decrease in ombrophilous forests. A resurgence in arboreal elements recorded in the Late Holocene indicates an expansion of ombrophilous forests under wetter climate conditions and the establishment of a more continuous forest matrix, with the presence of likely “hyperdominant” taxa. Frequent local fire events and the occurrence of temporarily correlated archeological sites in the Serra Leste region suggest the influence of ancient indigenous communities on vegetation changes during the Late Holocene.

ABSTRACTMulti Verse Optimization (MVO) technique is a newly developed population based algorithm established on the perception of white holes and black holes in a multi-verse for finding out all possibilities of search spaces. This algorithm is applied to tune the proposed Fractional Order Proportional Derivative Proportional Integral (PPDPI) controller of a multi area power system having hydro, thermal, and gas power plants in each area and the system is analysed in two different prospects i.e.with HVDC link and without HVDC link to have realistic situation. The effectiveness of the proposed controller tuned with MVO for load frequency control under small load perturbation (SLP) is compared with other well-known optimization algorithm for the same power system. In this paper, a Fractional-Order Cascade Controller (FOCC) is proposed which is the combination of both the concepts of fractional calculus and cascade control. Cascade connection of FOPI and FOPD are combined in the proposed controller. Change in load and change in system parameters are also incorporated to verify the robustness of the power system where the controllers tuned by the proposed MVO technique. It is observed that the MVO tuned controllers outperformed the performance of recently published TLBO and DE tuned controllers in the area of dynamic performance, stability, and robustness.

Phycoremediation is an eco-friendly and low operational-cost technique. It promotes green technology for biofuel production, high nutrient recovery, and wastewater treatment through microalgae. This review encompasses a set of algal-based remediation methods for potentially toxic elements (PTEs) from agricultural discharges and industrial wastewater. Large-scale algae production approaches, such as suspended cultures in open ponds or closed reactors and immobilized cultures, include biofilm and matrix-immobilized systems for biomass and the removal of wastewater nutrients, as well as PTEs. Fundamentals for remediation of PTEs using microalgae are biosorption and bioaccumulation, and thus, this review summarizes how microalgae are beneficial for wastewater treatment. Further, this review describes recent technologies, i.e., bioreactors, high-rate algal ponds, commercial sorption, etc., used in wastewater treatment and their specifications and eco-friendly remediation of contaminants from agricultural and industrial effluent. Wastewater treatment process utilizes algae or macro-algae in both conventional facultative ponds and advanced algal ponds, such as high-rate algal ponds with photo-bioreactors. This review also covers the advancement in the bioremediation of nutrients and PTE contaminants in agricultural and industrial wastewater using microalgae. Lastly, this review concluded with various limitations, challenges, and prospects on algae implications in wastewater, considering carbon neutrality and circular economy.

Green sand mixtures which are used for moulding purposes in foundry industries should possess sufficient green compression strength, flowability, toughness and air-permeability. Usually, the aforementioned properties for a particular casting differ due to variation in composition of the moulding sand mixtures, sand grain shape and size, bonding capacity of the binder, type and quantity of additives used, etc. The present work focuses on the effect of various additives namely, camphor powder, coconut shell ash, mixture of camphor powder and coconut shell ash at diverse proportions on permeability and green compression strength of the sand moulds. The quantity of the aforementioned additives for experimentation was varied from 0.5 to 3.5 wt. %. It was found that the mould’s permeability increased on addition of 1 wt. % additives for all cases. Similarly, the optimum quantity of additives that needs to be added to the sand mixtures for enhancing green compression strength was found to be 2 wt. %. Among all the additives used for improving the mould’s permeability, substitution of camphor exhibited best results. The green compression strength was found to be highest for the coconut shell ash containing sand mould. The moulding sand containing a combination of camphor powder and coconut shell ash between 1 to 2 wt. % exhibited fine mould permeability along with sufficient green strength.

Chitosan grafted with poly(methyl-methacrylate) (PMMA) and adsorbed with kaolin functionalized as bioadhesive was prepared via emulsion polymerization technique and physiochemically characterized as a bone-graft substitute. The so prepared grafted bioactive bone cement (BBC) bionanocomposites (BNCs), chitosan-g-PMMA/kaolin, was characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FESEM) and thermogravimetric analysis (TGA). The water uptake, retention ability and the nanosize particle arrangement in the polymeric BBC-BNCs were studied along with the mechanical and biodegradation properties. These preliminary investigations of the BNCs will open the door for their use in bioadhesive bone-cement implants in the future.

Various compounds that are emerging contaminants pose a significant risk to aquatic ecosystems and human health due to their potential to harm human health and the environment.Thus, there is an urgent requirement to use effective remediation methods and techniques to minimize the harmful impact of these contaminants on the environment. Biochar (BC) is a lightweight black residue that is made of carbon after the pyrolysis of biomass. BC is a product that is stable, rich in carbon, and exhibited improved properties. BC has come up with fascinating properties and results to remediate these pollutants from the soil effectively. Furthermore, it becomes possible to recover resources using BC because of the benefits such as (a) it offers in terms of cost, (b) the preservation of nutrients, and (c) the efficiency with which it absorbs pollutants. Consequently, it is necessary to have a knowledge of the interaction involving biochar and resource recovery to explore the applicability of BC in the cleaning up of the surroundings and the exploitation of wastewater. This review emphasize the physio-chemical and biological modification methods for the preparation of various types of engineered BC. Therefore, the present review aims: (i) provide an overview of emerging pollutants of human activities in soil (ii) synthesis and engineer BC for field application (iii) critically discuss and evaluate the factors affecting large-scale application techno-economic challenges. The review provided insight into the areas that need immediate attention in the upcoming investigation regarding the use of engineered biochar for wastewater treatment.

Poly (acrylonitrile-co-methyl acrylate) copolymer and P(AN-co-MA)/sodium silicate (SS) nanocomposite were synthesized via non-conventional emulsion method using an in situ transition metal complex Co(II)/EDTA and ammonium persulfate (APS) as initiator. The copolymer and nanocomposite so obtained were characterized and the results were compared. UV-visible spectral analysis revealed various interactions between the in situ complex and other reaction components. Infrared and 1H NMR spectra confirmed the formation of the P(AN-co-MA) copolymer and P(AN-co-MA)/SS nanocomposite. Furthermore, as evidenced by transmission electron microscopy (TEM), the composite obtained was found to have nano scale structure. X-ray diffraction (XRD) studies were carried out to analyze the aqueous dispersions of silicate with monomers, initiators, and monomers with initiators. For P(AN-co-MA) copolymer and P(AN-co-MA)/SS nanocomposite, XRD results confirmed that the silicate layers were exfoliated in the copolymer matrix during the polymerization process. An increase in the thermal stability for the nanocomposite was recorded by thermo gravimetric analysis (TGA). In comparison with the P(AN-co-MA) copolymer, the new P(AN-co-MA)/SS nanocomposite was found to show super absorbency and was biodegradable when tested by soil burial, activated sludge and cultured media and further confirmed by scanning electron microscopy (SEM).

Poly(2-ethyl hexylacrylate) (PEHA)/silicate composites were synthesized by the emulsion polymerization of ethyl hexylacrylate (EHA) in the presence of sorbitol and the composites were analyzed to be of nano order. The nanocomposites so prepared were shown to be intercalated by X-ray diffraction, transmission electron microscopy, and infrared spectroscopy. The thermal stability of the nanocomposites was found to be appreciably increased. These nanocomposites are potentially suitable for novel uses such as pressure-sensitive adhesives and superabsorbents. The biodegradability and superabsorbency of these nanocomposites were evaluated for their commercial potential. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1007–1011, 2004

The characteristics of nonconventional (soap-free) aqueous emulsion polymerization reactions of methyl methacrylate were evaluated by the catalytic effect of in situ developed different transition metal (II) chelate complex with amino acids initiated by different peroxo salts like potassium monopersulfate (KMPS, KHSO5), potassium persulfate (KPS, K2S2O8), ammonium persulfate (APS, (NH4)2S2O8). From the comparative data, the CuSO4/histidine chelate complex was selected as a novel catalyst for a detailed kinetic and spectrometric study of polymerization. Both kinetic and thermodynamic aspects of the polymerization dictate which initiator and particle morphology are obtained. The complex catalyzed polymerization proceeded smoothly until high conversion and yielded stable emulsions. The apparent activation energies (Ea) for the complex catalyzed emulsion polymerization were computed for different initiators to be 34, 38, and 46 kJ mol-1, each a very low value. Use of these values and activation energies of propagation and termination for MMA gave an unexpectedly low activation energies (Ed, 26, 34, and 51 kJ mol-1for KMPS, KPS, and APS respectively) to the decomposition of different persulfate initiators in the complex catalyzed system. The emulsion polymer latex was characterized through the determination of average molecular weights of the purified polymers by gel permeation chromtography (GPC) and viscosity methods and the morphology by scanning electron microscopy (SEM). The coordination complex catalytic system shows excellent industrial performance characteristics in preparing micro- to nano-scale latex particles.