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High-voltage insulators were developed from CaCO3 derived from waste snail shell to replace the low-impact energy ceramic insulators. Taguchi-grey (GRA) multi-response analysis was experimentally used to assess the effects of the processing parameter. The multi-response variables chosen were the dielectric constant, water absorption, and impact energy. The findings show an optimal point of 15 wt% CaCO3-snail shell, 120 °C curing temperature, and 6 h of curing time. The anticipated GRA was quite close to the experimental GRA at a 95% confidence level. This proved the effectiveness of the best processing settings. It was established that waste snail shell could be used in the production of high-voltage insulators that can withstand voltages up to 13.5 kV with high ultraviolet radiation resistance. [ABSTRACT FROM AUTHOR]

The surface hardening of mild steel by carburization using periwinkle shell nanoparticles (PWSnp) and coconut shell (CS) was investigated. The carburization was done at 850, 900, and 950 °C with a ratio of PWSnp:CS of 1:9, 2:8, and 3:7. The case depth, hardness values, wear, and corrosion rates were determined. A 114.1% increment in the hardness values, a corrosion protection efficiency of 92.58%, and a 45.67% wear resistance of the mild steel were obtained at 3:7 PWSnp: CS and 950 °C. The development of a passive layer that enveloped the sample and shielded it from further corrosion assaults was responsible for the excellent protection efficacy of the carburized sample. It was established that waste periwinkle shell and coconut shell can be used for surface hardening of mild steel. [ABSTRACT FROM AUTHOR]

High thermal conductivity and dielectric materials with enhanced electrical conductivity are needed in advanced electronics. However, simultaneous improvement in this material remains a challenge. Here, the synergistic effect of dielectric materials and the high thermal conductivity of epoxy-carbon nanotube decorated with waste eggshell through the Taguchi-Grey experiment have been studied to achieve this challenge. The composite was produced by the solution stirring method. The dielectric constant, thermal and electrical conductivity, and morphology of the samples were evaluated. The optimal condition of the composite for higher electrical and thermal conductivity was obtained at 1wt%ESp, 2.5wt%CNTs, 90oC curing temperature, and 6 hours of curing time with 19,130% and 94.27% increments in thermal and electrical conductivity. The predicted grey relational grade was close to the experimental grey relational grade at a confidence limit of 95%. This validated the efficacy of the obtained optimal processing parameters. It was established that waste eggshells can be used to ensure good dispersion of CNTs for the production of conductive polymers for improved electrical and thermal conductivity. [ABSTRACT FROM AUTHOR]

In the past, ceramic materials were exclusively used as transmission insulators for high voltage. However, due to the drawbacks of ceramic materials, including their heavy weight, challenging production, and poor toughness, high-voltage transmission insulators are now being replaced by polymeric materials. The majority of the issues with ceramic insulators are addressed by polymeric insulators. This study aimed to enhance the toughness and insulating properties of an epoxy composite developed SiO2 nanoparticles obtained from rice husk. The samples were produced by the solution stir cast method. The microstructure, impact strength, fracture toughness, and insulation properties of the developed composite were determined. The toughness and insulating properties that have been reported are within the acceptable range for high-voltage insulators. The developed composite insulator was found to be capable of withstanding voltages of up to 14.9 kV. The developed composite might be utilized to produce electrical insulators with great toughness and good insulating properties. [ABSTRACT FROM AUTHOR]

A high performance supercapacitor was produced by synthesizing graphite using froth flotation and graphene from waste rice husk using the doped casting method. The composition of the graphene was kept constant (Gr0.3 g) and the graphite was varied (0.1–0.2 g). The supercapacitor was produced by the doping method. The microstructure, cyclic voltammetry, electrical impendence spectroscopy, and X-ray diffraction were determined. Increasing the concentration of graphite increases the specific capacitance of the graphene/graphite (Gr/G) composite electrode. Enhanced supercapacitors with a specific capacitance of 2842.43Fg−1 at a scan rate of 5 mV/s can be made using 0.2 g graphite doped with 0.3 g graphene. An increase in the surface area of the composite material facilitated fast ion and electron transportation, thereby improving its electrochemical properties. This research has shown that high-quality supercapacitor electrodes may be made from waste rice husk and graphite ore using froth flotation, chemical methods, and doping. [ABSTRACT FROM AUTHOR]

This study examines the impact of sporadic rolling on the mechanical properties and microstructures of the Mg-8% Li/bagasse nanoparticle composite. Using the stir casting method, bagasse nanoparticle-reinforced composites were developed and rolled with thickness reductions of 50, 70, and 90%. Research on the microstructures of rolled composites shows that when aspect ratio decreases, fine, elongated grains grow in thickness and decrease in reduction. Additionally, it can be seen that by increasing the percentage of rolling, the β phase dissolves and the ductility of the composite is decreased. Comparing the interrupted rolled sample to the as-cast composite, the hardness is greater. At a 90% reduction, the yield has greater yield strength of 223 MPa. Because of the effective reduction in particle size, the hardening capability of composites reduces as the reduction percentage increases. It has been established that interrupted rolling affects the mechanical and microstructures of Mg-8% Li/bagasse nanoparticle composite. [ABSTRACT FROM AUTHOR]

Low-cost biosynthesized silver nanoparticles (GAgNPs) were used to enhance the properties of Al-carbon nanotube (CNTs) composites. Al-x% CNTs (× =0, 1, 2, 3, 4) and Al-x% CNTs (× =0, 1, 2, 3, 4) with 2%GAgNPs were produced using high intensive ball milling and spark plasma sintering. The densification, electrical conductivity, microstructure, hardness values, and wear rate were determined. The balling milling of the powders and the SPS method used in the production of the nanocomposites help to close the micro-voids in the materials with high values of densification. Higher dislocation density was obtained for the Al-4%CNTs+2%GAgNPs nanocomposites. A 7.8% and 93.11% raise in the electrical conductivity was obtained for Al, Al-4%CNTs, and Al-4%CNTs-2%GAgNPs composites. It can be concluded that the wear behavior of the Al-CNTs-GAgNPs nanocomposites was affected by the good densification of the composites, homogenous distribution of the reinforcement, and hardness values of the nanocomposites. It was established that a lower coefficient of friction and wear rate with higher electrical conductivity can be obtained with the developed Al-CNTs+GAgNPs nanocomposites. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) are special type of alloy suitably developed for use in petroleum exploration, energy storage devices, medical implants, etc. This is because they possess excellent corrosion, thermal, and mechanical properties. Corrosion characteristic of HEAs prepared via spark plasma sintering is a top notch as the technique generates corrosion resistant phases and homogenous microstructure. This study was aimed at reviewing recent publications on corrosion characteristics of HEAs processed by SPS in order to develop ways of improving their anti-corrosion properties. The resource materials were obtained from Scopus-indexed journals and Google Scholar websites of peer-reviewed articles published within the last 5 years. From the study, it was revealed that incorporation of some elements (Al, Cr, Ti) into HEAs can improve their corrosion resistance, while addition of some others can reduce their brittleness and enhance their stability and formability. It was recommended that optimization of SPS parameters was one of the strategies of generating better corrosion characteristics in HEAs. [ABSTRACT FROM AUTHOR]

The impact of the hydrophilic and hydrophobic CaO nanoparticles (CaOnp) and the techniques used to deposit them on glass and silicone rubber (PDMS) substrates was investigated. The purpose of this study was to ascertain the impacts of all variables relevant to deposition methods and interactions between nanoparticles and substrates on the hydrophobicity and wettability of surface materials. In order to assess the properties, dipping, spraying, and drop-pipetting methods were used in the deposition of the samples. The microstructure, contact angle hysteresis (CAH), and static contact angle (SCA) measurements were utilised. The findings show that the hydrophobic CaO nanoparticles and the PDMS substrate that interacted synergistically produce more beneficial hierarchical topologies with reduced surface energy, PDMS surfaces were developed utilising the spray deposition approach in combination with hydrophobic CaO nanoparticles, and both horizontal and vertical drying procedures satisfy the two criteria for a self-cleaning surface and superhydrophobic. [ABSTRACT FROM AUTHOR]

Recent advances in cellular porous materials for improved performance in their areas of application require the integral design of their porous structure. In this work, open-cell porous aluminium with pores of spherical geometry and interconnecting windows were fabricated using the replication casting method by infiltrating porous preform formed by packing sodium chloride spheres of two different size ranges (1.4–2.0 mm and 2.0–2.5 mm diameters) with molten aluminium under externally applied differential pressure of between 0.01 and 0.1 MPa. The preform was removed by water dissolution which resulted in the formation of porous materials. The influence of infiltration pressure on the window size and relative density of open-cell porous aluminium manufactured was investigated. The resulting open-cell porous aluminium structures were characterized by using the micro-computed tomography and optical and scanning electron microscopes. The results show that within the range of applied pressure, the relative density of the open-cell porous aluminium structures increases as the infiltration pressure is increased, while the window diameter of the porous samples decreases as the applied pressure is increased. A geometric model based on interaction between poorly wetted sodium chloride particles and molten metal which leads to the formation of windows is proposed for the estimation of window radius of porous metals fabricated by replication casting. The estimated window size based on the geometric model is in good agreement with the measured window diameter of the experimental samples. [ABSTRACT FROM AUTHOR]

Due to the low toxicity, high theoretical capacity, abundant resources, low potential, of zinc oxide (ZnO), it is regarded as the next-generation lithium-ion battery anode material. However, because of the significant drawback in terms of volume expansion during the charge-discharge cycles, ZnO is easily pulverized and agglomerated. In this research work, we synthesize 0.5 g of rice husk-derived graphene (R 0.5) and 1.0 g of ZnO (Z 1.0) composite (R 0.5 Z 1.0) to accommodate the volume expansion of ZnO during the charge-discharge process as a next-generation lithium-ion battery anode. Rice husk as a graphene source will support the future usage of bio-based materials for active material synthesis. The samples were characterized via SEM, XRD, and Fourier infrared spectroscopy, and with a discharge capacity of 895.2 mAhg−1 at a current density of 200 mAg−1 after 110 cycles, the composite material demonstrated remarkable Li storing characteristics and electrochemical performance as an anode for lithium-ion battery application. [Display omitted] • Rice husk is a potential graphene source via chemical activation. • Rice husk derived graphene and zinc oxide composite is a promising anode for lithium-ion battery application. • Faradic charge transfer resistance of zinc oxide can be greatly reduced by incorporating rice husk derived graphene. • Agglomeration challenge of zinc oxide can be reduced by introducing rice husk derived graphene. [ABSTRACT FROM AUTHOR]

Electricity transmission is an essential intermediary linking power generation and distribution. Voltage drops or total blackouts have always characterized the transmission and distribution of electricity in the sub-Saharan Africa and some Asian dwellers. This has been attributed partly to faulty, defective or dilapidated transmission conductors/networks. The aim of this study is to identify the causes of those defects in the transmission conductors and proffer possible remedies to them. Studies have shown that the current production techniques of transmission conductors (TCs) generate defective products, and that the materials used have their own challenges too. This work, therefore, reviewed all the production techniques and materials used in the development of TCs. It was observed that pultrusion, extrusion, hot-rolling, and stir-casting were the techniques used in the production of transmission conductors. Defects such as shrinkage, pores, impurities, and warps were identified in those techniques and some recommendations to ameliorate the defects of those techniques were presented. Spark plasma sintering is recommended as the most promising solid- state production techniques that should be adopted in fabricating transmission conductors, though it is yet to be developed for producing long-span products. In addition, advanced TCs materials such as Al-CNTs, Al-Nb, Al-Ti, and Al-B2 were presented as better alternatives to the existing TCs materials. By producing TCs with the recommended techniques and materials, the electricity availability will be enhanced; and this will lead to sustainable industrial growth and economic stability in the third world countries and the entire world. [ABSTRACT FROM AUTHOR]

Wear behavior of titanium alloys of Ti-4.5wt%Al + xFe (x: 2,4,6,8) produced by spark plasma sintering was investigated in order to highlight the effects of the iron additive on wear rate and coefficient of friction (COF). These research objectives were accomplished by a dry sliding experimental technique using the Tribometer (version 8.1.8) Anton Paar machine, which was carried out under normal loads at 10 N and 20 N with a linear speed of 0.06 cm/s. Scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques were used to characterize the titanium alloy specimens. The results indicated that the wear rate increases with an increase in the applied normal load. A minimal coefficient of friction of 0.047 and a wear rate of 1.033 × 10−5 (mm3/N/M) were observed for Ti-4.5 wt% Al + 4 wt% Fe with respect to sliding at 10 N. While at a normal load of 20 N, a minimal friction coefficient of 0.015 and a wear rate of 1.74 × 10−5 (mm3/N/M) were obtained for Ti-4.5 wt% Al + 4 wt% Fe. [ABSTRACT FROM AUTHOR]

Abstract: The effects of varying silicon carbide on the hardness values of heat-treated Al–Si–Fe/SiC particulate composites have been investigated. The 5–25% SiC additions were used for the production of different grades of Al–Si–Fe/SiC particulate composites. The composites samples were solution heat-treated at 500°C for 3h and quenched in warm water at 65°C, aged at 100, 200 and 300°C with various ageing time between 60 and 660min at 60min interval. Hardness measurements were made using Rockwell hardness tester. Experimental correlations obtained between the varying silicon carbide addition, heat-treatment parameters and the hardness values were analyzed using kinetic of ageing and factorial analysis (2K). The results show that hardness increases with increasing percentage of silicon carbide addition in the alloy and decreases with increasing ageing time. These results, which are in agreement with the experimental findings for these ageing time and temperatures. The increases in hardness values during ageing are attributed to formation of a coherent and uniform precipitation of the second phase in the matrix of the metal. A substantial improvement in hardness has been achieved in the reinforced metal matrices produced. [Copyright &y& Elsevier]

The increased demands for eggs for consumption have large increases in the deposition of eggshells as environmental pollution worldwide and increase high management costs. To reduce the management costs of eggshells, this work attempt was made to utilize eggshells as a source of CaCO3 for improving the hardness values and wear behavior of composite coating on mild steel. The composite coating was produced using 0, 5, 10, 15, and 20 g CaCO3-derived eggshell particles. The response surface method was used to determine the influences of applied load, sliding speed, and weight of CaCO3-derived eggshell particles on the wear behavior. The results have shown that Zn- CaCO3-derived eggshell particles composite coatings were successfully formed on mild steel. A 90.17% improvement of hardness values was obtained at Zn-20 g CaCO3-derived eggshell particles. The Zn-20 g CaCO3-derived eggshell particles sample has a lower friction coefficient. Wear rate increase with the increase in applied load and sliding speed. The optimum condition was obtained at CaCO3-derived eggshell particles (+ 1), applied load (− 0.35), and speed (− 0.58) with the lowest wear rate of 0.99 mm3/Nm. It has been recommended that the Zn-20 g CaCO3-derived eggshell particles composite coating of mild steel can be used in areas where wear and roller body are paramount. [ABSTRACT FROM AUTHOR]

Minimum quantity lubricant (MQL) (nanofluids) is a promising method used in decreasing cutting force and surface roughness and improving tool and productivity. This work deals with the analysis of low-cost SiO2-derived from rice husk ash (SiO2-RHA) nanofluid on the machining of aluminum alloy. L9 Taguchi orthogonal array of nine (9) runs were used to determine the effect of lubrication condition, cutting speed, feed rate, and depth of cut on the turning operation of the aluminum alloy. Analysis of variance (ANOVA) indicates that SiO2-RHA nanofluid has a higher significant effect in lowering the tool wear and cutting force and good surface finish. The SiO2-RHA nanofluid has a contribution of 92.96%, 88.59%, and 93.40% in decreasing the cutting force and tool wear and good surface finish. It was established that the low-cost rice husk waste can be used in the production of nanofluid for the machining (turning operation) of aluminum alloy. [ABSTRACT FROM AUTHOR]

The blending of waste tin tailings with graphene derived from waste rice husks in the production of high-specific capacitance supercapacitors was developed in this work. Alkaline treatment method was used to develop graphene from rice husks. The doping casting method was used to produce 0, 10, 20, and 30 wt% graphene with constant 20 wt% tin tailings. Cyclic voltammetry (CV), electrochemical impedance spectroscopy, scanning electron microscopy, and X-ray diffractogram (XRD) were used to analyze the composite electrode material. The specific capacitance rises with an increase in the dopant graphene of up to 30% with a specific capacitance of 379.58 at a 5 mV/s scanning rate. The high specific capacitances obtained are within the standard for flexible supercapacitors. It was established that waste tin tailings and graphene derived from waste rice husks could be used in the production of low-cost supercapacitors. [ABSTRACT FROM AUTHOR]

The ability of epoxy composites to provide both high toughness and outstanding electrical conductivity is critical in several technical applications such as boards, electronic devices, anti-static electricity, and electromagnetic shielding. However, it was difficult to obtain the high toughness and electrical conductivity of conducting polymer to suit this purpose. Hence, this work will investigate the fracture toughness and electrical conductivity of epoxy/carbon nanotube surfaces coated with CaCO3 derived from waste eggshell (CNTs/CaCO3-ESp) for high toughness and electrical conductivity. The CNTs/CaCO3-ESp was produced by growing CNTs on CaCO3-ESp through a chemical hybridization process. The CNTs were firmly attached to the CaCO3-ESp and enhanced the dispersion of CNTs in the epoxy matrix. The electrical conductivity and fracture toughness of the epoxy/1.5wt% CaCO3-ESp-CNTs were improved by 235,789% and 6.51%, respectively. The fracture surface shows homogenous dispersion of CaCO3-ESp-CNTs in the epoxy matrix. It was found that used eggshells can be used to change CNTs so that they can be used to make epoxy composites with better strength and electrical conductivity for the electronics industry. [ABSTRACT FROM AUTHOR]

Biofuel, a cost-effective, safe, and environmentally benign fuel produced from renewable sources, has been accepted as a sustainable replacement and a panacea for the damaging effects of the exploration for and consumption of fossil-based fuels. The current work examines the classification, generation, and utilization of biofuels, particularly in internal combustion engine (ICE) applications. Biofuels are classified according to their physical state, technology maturity, the generation of feedstock, and the generation of products. The methods of production and the advantages of the application of biogas, bioalcohol, and hydrogen in spark ignition engines, as well as biodiesel, Fischer–Tropsch fuel, and dimethyl ether in compression ignition engines, in terms of engine performance and emission are highlighted. The generation of biofuels from waste helps in waste minimization, proper waste disposal, and sanitation. The utilization of biofuels in ICEs improves engine performance and mitigates the emission of poisonous gases. There is a need for appropriate policy frameworks to promote commercial production and seamless deployment of these biofuels for transportation applications with a view to guaranteeing energy security. [ABSTRACT FROM AUTHOR]