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Magnesium is one of the largely available elements in the earth's crust. It has a low structural density with high specific strength. This unique material property has forced an increase in the use of magnesium and its alloys in various applications pertaining to industrial sector, automobiles, aerospace and biomedical. Since magnesium is a highly reactive metal, it is prone to higher rate of corrosion as compared to its counterparts. Thus, it is essential to analyze the corrosion behavior of magnesium and its alloys in its applications. An appropriate process is to be followed in the design and development of magnesium alloys which overcome the limitations of magnesium and enhance the desired material properties in accordance to their applications. This review paper summarizes the importance of magnesium and its material properties. The influence of various alloying elements on the mechanical properties of magnesium is reviewed. The broad classification of Mg alloys and their behavioral trends are detailed. The corrosion behavior of magnesium and the influence of corrosion products on the material characteristics of magnesium, in aqueous medium, are discussed. The manufacturing techniques of magnesium alloys along with the secondary techniques are also covered. The various applications and the limitations of magnesium in these applications are covered. A complete section is dedicated towards detailing the recent trends of magnesium (Mg) alloys, i.e., the biodegradable nature and applications of Mg alloys. The influence of biocorrosion on Mg alloys and techniques to overcome it have been deliberated. This paper provides a thorough review on recent developments of magnesium with respect to engineering applications. [ABSTRACT FROM AUTHOR]

The current work describes the fabrication of Fe-doped zinc oxide thin films on a glass substrate using sol-gel spin coating technique. The undoped and Fe-doped ZnO films were annealed at the 400 °C for 3 h. The structural, optical, morphological and luminescent features were explored by using X-ray diffraction (XRD), diffuse reflectance, scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy techniques. It was noted that XRD patterns showed the polycrystalline nature and demonstrated a hexagonal wurtzite structure of Zn 1-x Fe x O. With the rise in Fe ratio, the grain sizes of the deposited films start to cut as revealed from the SEM images. Interestingly, no variation has been noted in the transmittance value in the visible region. However, a lessening in the band-gap energy with an increment in the Fe concentration has been seen. PL curves exhibit ultraviolet emission peaks at 398 and 485 nm that are associated with the near band edge emission (NBE) and defect emission peak. It has been noted that the NBE emission shifts to longer energy with the rise in the Fe ratio. These results demonstrated the applicability of ZnO thin films as a suitable material for light emitting applications. [ABSTRACT FROM AUTHOR]

Pure and Mg-doped ZnO thin films have been fabricated by a sol-gel spin coating method. The as prepared films were annealed at 400 °C. The structural, optical, morphological and luminescent characteristics were studied by using X-ray diffraction (XRD), diffuse reflectance (DR), scanning electron microscopy and photoluminescence spectroscopy techniques. XRD results show the polycrystalline behavior of deposited films without any impurity or formation of extra phase. DR spectra exhibit the blue shift in the absorption edge gap after Mg doping. It has been observed that the band-gap of the fabricated films rises with the increase in the Mg doping. The obtained results have been explained by existing literature and a good comparative study has been made. [ABSTRACT FROM AUTHOR]

Metal-substituted spinel ferrite-based microwave absorbing materials (MAMs) are attracting significant attention due to their varied soft magnetic behaviour, and ease of synthesis. This work established the efficiency of Cd2+ substituted nickel ferrite coated MWCNT (with varied MWCNT loading) for X-band microwave absorption, in the presence of PVDF. The substituted ferrite was prepared with a facile solvothermal process. X-ray diffraction and vibrating sample magnetometer analysis confirmed the spinel structure of substituted ferrites and tuned magnetic behaviour of Cd2+ substituted ferrite structure, respectively. FESEM revealed a uniform coating of substituted ferrite on MWCNT and XPS confirmed Cd2+ substitution. Hybrid nanocomposites of ferrite coated MWCNT with PVDF, in the epoxy matrix, revealed superior microwave absorption for NiF-150_10 PV and CdNiF-150_10 PV with an absorber thickness of 3 mm in the X band. The absorption bandwidth with the RL below −10 dB reached 3.9 GHz and 3.6 GHz for NiF-150_10 PV and CdNiF-150_10 PV, respectively. The microwave absorption mechanism was discussed in detail. The developed NiF-150_10 PV and CdNiF-150_10 PV composites can be used as lightweight, low thickness microwave absorbers in the defense and telecommunication industries. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract The combined fuzzy analytical hierarchy process (F-AHP) and fuzzy technique for order preference by similarity to ideal solution (F-TOPSIS) approach used to access performance defining attributes (PDAs) such as Tensile Strength, Flexural Strength, Impact Strength, Elongation at break (%), Diffusion Coefficient (D), Sorption Coefficient (S) and Permeability Coefficient (P) of fabricated biodegradable composite materials. The weight of different PDA's was evaluated by F-AHP where the PDA's are Tensile Strength, Flexural Strength Impact Strength, Elongation%, Diffusion, Sorption and Permeability. F-TOPSIS was employed to determine the optimal ranking of the composite materials as BC-1>BC-7>BC-2>BC-6>BC-5>BC-3>BC-4. The alternatives other than neat PCL, with fiber, matrix and graphite at 45, 55 & 15 wt fraction (i.e., BC-7) showed optimum results. Highlights • A novel Pine Cone reinforced biodegradable composite was developed and characterized. • Comparable mechanical properties were achieved along with biodegradation of the composites. • Hybrid MCDM approach was incorporated (F-AHP TOPSIS) for selecting optimal combination. • F-AHP and F-TOPSIS was found to be a competent MCDM technique. [ABSTRACT FROM AUTHOR]

Abstract Flower like ZnO and plate like CuO were fabricated upon rGO and Nitrogen doped rGO following a simple scalable cheapest facile hydrothermal treatment. XRD, FTIR and XPS analysis confirm the Formation of N-doping on rGO as well as all composites. FESEM analysis reveals the distribution of metal oxide upon the graphene nanosheets. Electrochemical activity in case of ZnO-CuO/N-rGO nanocomposite in 1 M aq. KOH exhibits 1075 Fg−1 specific capacitance (SC) at 1 Ag-1 current density. We also derived a superior energy density (ED) value of the fabricated nanocomposite to be 95.55Whkg−1 with power density (PD) 399.97 Wkg-1. Additionally, the electrode made up of hybrid ZnO-CuO/N-rGO nanocomposites displays excellent cyclic stability of 88% retention of specific capacitance after completion of 5000 cycles. These outcomes specify a hopeful prospective approach of the ZnO-CuO/N-rGO nanocomposite as a successful electrode substance in supercapacitors. Highlights • The paper first time reported facile synthesis of ZnO-CuO/N-rGO nanocomposite. • The ZnO-CuO/N-rGO showed specific capacitance 1075 F/g at 1 A g−1. • Electrochemical study is performed in both three and two electrode system. • The two-electrode system shows a high energy density 238.93 W h kg-1 and power density 1601 Wkg-1 at 1 A g−1. • 88% retention of specific capacitance also exhibited even after 5000 cycles of GCD. [ABSTRACT FROM AUTHOR]

Abstract In this paper, the electrical resistivity, morphology and dynamic mechanical properties of in-situ reinforced microfibrillar composites (MFNC-C) based on polypropylene reinforced with polyethylene terephthalate (PET)-multiwalled carbon nanotubes (MWCNT) fibres have been investigated. Influence of various factors such as the effect of the morphology, CNT composition and the nano compatibilizer effect of CNT on the in-situ reinforced microfibrillar nanocomposites, have been analysed. The dynamic mechanical analysis (DMA) showed that the storage modulus microfibrillar composites are precisely related to the fibrils morphology and composition of CNT. It is found that the presence of CNTs on the fibrils surface has improved the storage modulus as well as normalized storage modulus. The results of four probe analysis showed that by increasing CNTs content, the resistivity remarkably decreased with respect to the morphology of the of nanocomposites. Also, scanning electron microscopy images likewise revealed that the preferential localization of MWCNT on to the PET microfibrils enhanced the compatibility between PET fibrils and PP matrix. Hence, The in –situ formation of fibrillar morphology along with MWCNTs is highly useful in terms of mechanical and electrical performance of the resultant nanocomposites. We assume that the optimized results of this work may open an alternative path for the production of commercially important polymer nanocomposite based on the incompatible immiscible blends. Graphical abstract Image 1 Highlights • Electrical resistivity, morphology and dynamic mechanical properties of in-situ reinforced microfibrillar nanoccomposites (MFNC) based on polypropylene reinforced with polyethylene terephthalate (PET)-multiwalled carbon nanotubes (MWCNT) fibres were investigated. • Four probe analysis showed that by increasing CNTs content, the VOLUME resistivity of nanocomposites remarkably decreases. • The formation of fibrils and introduction multiwalled carbon nanotube increased the electrical conductivity and storage modulus of in-situ reinforced microfibrillar nanocomposites (MFNC). [ABSTRACT FROM AUTHOR]

This paper presents an investigation of design and development of low elastic modulus porous biodegradable Mg-Zn-Mn-HA composite for orthopedic applications via mechanical alloying and spark plasma sintering (MA-SPS) technique. The effect of MA-SPS process parameters like milling time, sintering temperature and sintering pressure have been studied on the structural porosity, elastic modulus and hardness of as-synthesized composite. The percentage of structural porosity was determined by Archimedes method and the elastic modulus and hardness of as-synthesized alloy were measured by the nano-indentation method. HA compound induced composite not only refined the grain but also enhanced porosity, which favoured osseointergation. The microstructure examination of the MA-SPS synthesized composite reveals the formation of high degree of structural porosity (15–25%), witnessed at low alloying time and high temperature. Sintering pressure enables pores reduction and induces an additional driving force for the compaction and sintering temperature assists the powder particles to coalesce, which subsequently reduces the porosity, densified the compact, and enhanced the mechanical properties. XRD pattern analysis confirmed the formation of MgCaO, β-TCP, Mn-CaO, and Ca-Mg-Zn phases, enhanced mechanical properties and corrosion characteristics. The degradation rate of Mg-Zn-Mn-HA alloy was reduced from 1.98 mm/year to 0.97mm/year by the alloying of HA elements. [ABSTRACT FROM AUTHOR]

Herein, nanocrystals of Er 3+ and Er 3+ , Yb 3+ co-doped NaYF 4 upconversion (UC) phosphor were prepared via the reverse-microemulsion method. The impact of different concentrations of Er 3+ ions on the UC emission intensity after 980 nm diode laser excitation is discussed. The structure, morphology and composition of the nanophosphors were confirmed by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and the results showed the presence of NaYF 4 nanocrystals with hexagonal phases of NaYF 4 . The UC spectra revealed two emission bands including a green and a red emission band and the CIE coordinate for the samples were estimated. The present research revealed that the reverse-microemulsion approach will be suitable for the synthesis of efficient upconversion nanophosphors. [ABSTRACT FROM AUTHOR]

Boron nitride's (BN) large band gap does not permit carrier transport at ambient conditions. We show that BN sheets can be exfoliated by functionalization with oxy-groups to introduce additional acceptor and donor energy levels appropriate for energy storage devices. Further, the incorporation of heteroatoms into transition metal sulfides enhances capacitance via Faradic redox reactions and their cyclic stability. The functionalized boron nitride (m K -BN) and Carbon Nanotubes (CNTs) are intertwined with a Zn-doped Cadmium-Sulfide (Zn–CdS) nanostructure to increase the surface area-charge storage. In a supercapacitor application, Zn–CdS/m K -BN/CNT exhibits a 787 F/g specific capacitance (SC) in an aqueous (aq.) electrolyte. Further, the Zn–CdS/m K -BN/CNT was deployed as a cathode material in an asymmetric supercapacitor device (ASC) coupled with an ionic electrolyte (IE), (NHEt 3)+(NO 3)−, offered a SC of 173 F/g with an approximate 99% stability due to the enhanced charge mobility. The reported functionalization of BN induces additional energy levels making the material ideal for energy storage devices and will directly impact the next-generation of advanced supercapacitor electrode materials. [ABSTRACT FROM AUTHOR]

Abstract Single pot solvothermal synthetic procedure was followed for easy synthesis of n-TiO 2 /n-Gr composite for supercapacitor. FTIR, XRD, XPS and FESEM were executed to access the chemical nature, interaction, growth and morphology of the samples. In both three and two electrode arrangement, n-TiO 2 /n-Gr leads to 937.5 F/g and 633.75 F/g specific capacitance (SC) respectively. Enhanced SC may be due to facile electron carry-over in n-TiO 2 deposited n-Gr surface. This superior SC complemented with high energy density (ED) of 46.25 Wh/kg and power density (PD) 3999.51 W/kg. This composite also retains about 87% retention of SC after 5000 successive charge–discharge rounds. However, in organic electrolyte (1 M TEABF 4 in acetonitrile) with two-electrode testing configuration, the composite showed an energy density of 225.33 Wh/kg with high power density of 1599.7 W/kg. N doped in both TiO 2 and graphene enhanced the compatibility and electrochemical performances of electrode material and makes it a potential candidate for supercapacitor. Graphical abstract Image 1 Highlights • The paper first time reported template free, facile synthesis of n- TiO 2 /n-Gr composite. • The n- TiO 2 /n-Gr showed specific capacitance 937.5 Fg-1 at 0.6 A g−1. • Electrochemical study is performed in both three and two electrode system. • The two-electrode system shows a high energy density 225.33 W h Kg−1 at 1 A g−1. • 87% retention of specific capacitance also exhibited even after 5000 cycles of GCD. [ABSTRACT FROM AUTHOR]

Abstract The present research work is aimed to discuss a novel method of depositing hydroxyapatite coats, with interconnected pores, on the surface of bio-degradable Mg Zn Mn alloy by using hydxroxyapatite (HA) powder mixed electric discharge machining (HAM-EDM) process. The parameters of HAM-EDM process has been optimized using multi-objective particle swarm optimization (MO-PSO) technique to determine the optimal levels of concentration of hydroxyapatite powder (C HA), peak-current (I p), pulse-on (T on), and pulse-off (T off). The surface roughness (S R), thickness of recast layer (R LT), and micro-hardness (M H) were chosen as output response characteristics. The experiments were performed according to L 27 orthogonal array and an empirical model has been developed to interpret the co-relation amongst input and output parameters. A number of optimal solutions (∼100) were obtained by MO-PSO technique, where all responses were optimized. Among them, best optimal condition is to deposit biomimetic HA-containing layer with low SR (0.70 μm), low RLT (11.85 μm) and high MH (246 HV) was C HA = 5.28 g/l, I p = 3.48 A, T on = 40.33 μs, and T off = 109.29 μs? Further, the specimens produced were characterized, morphologically and topologically, and revealed the existence of hydroxyapatite (HA) layer with interconnected pores of 5–10 μm size. The EDS spectrum showed that presence of Ca, P, and O on the modified surface, which conferred the deposition of HA-layer on the surface. The XRD pattern investigations of modified surface confirmed the formation of various biocompatible phases, which enhanced the mechanical properties, corrosion and osseintegration characteristics. Highlights • Hydroxyapatite-enriched coating was deposited on Mg-alloy by using EDM process. • Effect of EDM parameters on the surface integrity and properties were investigated. • Taguchi's and Particle swarm optimization were exploited to optimize the EDM parameters. • Surface roughness and recast-layer-thickness were minimized and micro-hardness was maximized. • Biomimetic HA-layer composed oxides that enhanced the surface properties and bioactivity. [ABSTRACT FROM AUTHOR]

Alternative finding of toxic pollutant materials in proper utilization is a great challenge. Toxic and pollutant cigarette smoke having different π-conjugated organic components may work well as a precursor for carbon dots (CDs). In this work, cigarette smoke aerosol has been used for the synthesis of CDs and CDs have been further used for the fabrication of supercapacitor electrode. This methodology could be able to mitigate the two major problems-energy crisis and environment pollution. The smart combination of EDLC-type CDs deposited boron nitride (BN) and pseudocapacitive type Zn-doped MoS 2 was able to enhance the supercapacitive performances. Heteroatom doping into MoS 2 enhances the capacitive performances through the effective Faradic reactions. CDs and CDs deposited BN (CDs@BN) have been characterized using different characterization techniques. Zn-doped MoS 2 has been uniformly grown on the CDs decorated BN (Zn–MoS 2 /CDs@BN) resulting in the stabilization of the electrode system. Zn–MoS 2 /CDs@BN nanohybrid delivered a specific capacitance (Sp.C) of 397 F/g in three-electrode system. Further, the asymmetric supercapacitor (ASC) device using Zn–MoS 2 /CDs@BN as cathode demonstrated wide potential range (up to 1.8 V) with a volumetric energy density of 3.42 mW h/cm3 and retaining a capacitance of ∼89% after 10,000 charging-discharging processes. Moreover, a flexible ASC device was made-up using viscous ionic electrolyte and it was able to glow a red LED, while it was bended in different angles. The methods described here will give a straightforward approach for using toxic-pollutant cigarette smoke to fabricate supercapacitor electrodes in order to compensate the upcoming energy crisis in a sustainable way. Cigarette smoke aerosol derived carbon dots decorated boron nitride supported Zn-doped MoS 2 for high performance flexible asymmetric supercapacitor device in low-cost viable ionic electrolyte. [Display omitted] • For waste to wealth perspective, synthesis of CDs using toxic pollutant cigarette smoke aerosol for flexible asymmetric supercapacitor device. • Synthesis of CDs induced BN supported Zn-doped MoS 2 using a facile hydrothermal method for the enhancement of electrochemical efficiency. • Zn–MoS 2 /CDs@BN, as positive electrode for the asymmetric supercapacitor achieved an enhanced energy density of 119 W h/kg with ∼91% retention of specific capacitance. • ASC device revealed decent volumetric energy density of 3.42 mW h/cm3. • Fabrication of flexible asymmetric supercapacitor in low-cost viable ionic electrolyte. [ABSTRACT FROM AUTHOR]

The present work is focused on the replacement of Fe 3+ ions by rare-earth Nd 3+ ions and their influence on the cations distribution, structural, magnetic and Mössbauer properties of Mg-Mn nanoferrites. Nanosized Nd-doped Mg-Mn nanoferrites, Mg 0.9 Mn 0.1 Nd x Fe 2−x O 4 , where x = 0.1, 0.2 & 0.3, were successfully synthesized for the first time through solution combustion technique. X-ray diffraction studies confirmed the formation of single phase nature of the synthesized nanoferrites. Williamsons-Hall plots were used to obtain the particle size and strain while the lattice parameter was obtained from Nelson-Riley plots. The particle size was observed to decrease (19.2–13.5 nm) while lattice parameter was observed to increase (8.373–8.391 Å) with the incorporation of Nd 3+ ions. Cation distribution between the tetrahedral (A-site) and octahedral (B-site) was estimated by using the X-ray diffraction method & magnetization technique. The estimated cation distribution was used to investigate the detailed structural parameters. Room temperature M−H study revealed a decrease of saturation magnetization (10.15–1.83 emu/g) and an increase in coercivity (22.86–27.19 Oe) with the increasing substitution of Nd 3+ ions. Magnetic results obtained in the present study indicated that the synthesized nanoferrites can be a useful candidate for electromagnet applications. [ABSTRACT FROM AUTHOR]