The peculiar characteristics of Palm Kernel Shell (PKS) may have corresponding effects on polymer mono composites and hybrid composites when used as filler in polymer matrices. This review paper relates Palm Kernel Shell (PKS), palm kernel shell-mono composites, and palm kernel shell hybrid composites in terms of identification, sampling, and analysis. The purpose was to establish the properties of palm kernel shells and their composites as documented by various researchers in a one-stop-shop document for use by current and future researchers. The accidental and judgmental sampling procedures were employed to sample documents that relate palm kernel shells and polymers. The study revealed that lignocellulos palm kernel shell properties, including lignin, cellulose, and hemicellulose might vary depending on the geographic location of the plant from which the shell is derived. Similarly, the mineral content of PKS, such as carbon, iron, Aluminum, potassium, silicon, phosphorus, oxygen, and cesium, among others, were found to vary. Other properties identified include solid density, porosity, specific gravity, specific heat capacity, moisture content, and angle of repose. The paper also observed that using PKS as a filler material in polymer composites could modify the properties of the filler and hence PKS/polymer composites. The paper concludes that PKS may be a good filler material when used in the development of PKS/oil palm mesocarp/polyethylene hybrid composites. Chemical treatment of the PKS particles may further enhance the characteristics of the evolved hybrid composite material.

There has been an increase in research over the past decades into the use of environmentally friendly materials in brake pads, such as natural fibres. This is due to the possibility that natural fibbers could serve as an alternative to the noxious asbestos materials in tribological applications like brake pads. As a result, utilizing the compacting mould technique, an asbestos-free friction material was developed using agricultural waste (coconut shell and oil bean stalk) as a filler element, alongside aluminium dross, metal chip industrial wastes and carbon black. The filler material considered had particles as small as 300 μm, with epoxy resin serving as the binding agent. Using these waste materials can help reduce environmental pollution and the risk to animal and plant life (Preeti et al., Pharma Innov J 7:94–102, 2018; Sajib, A Study on the effects of environmental pollution on human life in the riverbank area of Barishal City Corporation (Kirtankhola River), 2021). This research aimed to replace asbestos in brake pads due to its carcinogenic nature, reducing the health risks associated with manufacturing and using these brake pads. The brake pad materials were cast and produced using square wooden moulds. Four samples were created, comprising the same mixing ratio but varying in reinforcement fibre and particle size, with epoxy resin used as the matrix. Various tests were conducted on these samples, including a water absorption test, specific gravity test, compressive strength test, hardness test, thermal conductivity, SEM and EDX. The developed brake pads underwent microscopic characterization and structural examination using a scanning electron microscope (SEM) fitted with energy-dispersive X-ray spectroscopy (EDX) for elemental characterization. Thermal conductivity was obtained using automated Lee’s Disc apparatus. Comprehensive strength analysis was conducted using a universal testing machine (UTM).The specific gravity tests yielded values for the developed composites in the range of 1.136–1.257, while the commercial brake pad had a value of 2.081, indicating that the produced samples were lighter and less dense. The water absorptivity of the developed samples ranged from 0.95 to 2.174%, while the commercial brake pad had a value of 1.031%. For the hardness tests, at three different loads, the developed values ranged from 16.4HV3 to 19.4 HV3; 26.4HV30 to 28.7HV30; and 25.5HV100 to 29.6HV100, while the commercial brake pad had values of 16.5HV3, 28.4HV30 and 28.2HV100.Sample C (212 μm: coconut shell powder) exhibited the most desirable characteristics with five values: water absorptivity 0.95, compressive strength 120.5 MPa, hardness value 29.6 HV100, wear resistance 0.099 mm/mm³, specific wear rate 1.00 mm³/Nm. The outstanding values were attributed to the chemical composition, particle sizes and good interfacial bonding of the microstructure.The developed brake pads performed favourably when compared with the existing commercial brake pads. The chemical tests showed that the natural fibres bonded well with the epoxy matrix. The thermal and mechanical tests yielded comparable results with the values obtained from the commercial brake pads. Therefore, the developed materials for brake pads can be considered suitable replacements for asbestos brake pads.

The most important part of the wind turbine is the blade. From existing studies, it has been concluded that most wind turbine blades have a high rate of failure during operation due to fatigue, because of a lack of proper material selection processes. Materials such as fiberglass, wood, aluminum, and steel have been used but have not been able to qualify as sustainable materials. Therefore, this study focuses on the review of existing materials employed for developing metal matrix composites as ecological materials to produce wind blades. This study discusses the application of aluminium, silicon, and magnesium metal matrix alloys and the implementation of agro-waste materials (coconut rice, coconut shell, rice husk ash, and sugar Bagasse ash) and eggshell as reinforcement particulates for metal matrix composites for developing wind blades. The study also reviews the method of production of matrix composites. From the results obtained via the review, it is clear that the application of eggshells assists as a binding element for proper mixture, and the combination of Al–Si–Mg alloy with coconut rice and shell improves the strength of the material, since wind blades need durable materials and ductility due to their aerodynamic shape to convert enough energy from the wind.

The world is now focusing on a sustainable environment and reducing the effects of global warming. One way to achieve such targets is to properly utilize waste and reduce greenhouse CO₂ emissions. The cement industry is responsible for almost 10% of global CO₂ emission due to the high demand for cement in the construction industry. One of the ways to minimize this effect is the partial replacement of cement by other materials in concrete. Therefore, in this study, calcium carbide residue (CCR), which is highly rich in calcium oxide, partially replaced cement for waste management. Waste tires were grinded to fine sizes in crumb rubber (CR) and partially replaced the fine aggregate. Therefore, this paper investigared the influence of CR and CCR on the durability properties and heat/temperature resistance of self-compacting concrete (SCC). The experiment was designed using response surface methodology to investigate the effects of CR and CCR on SCC properties, design models for properties of the SCC, and optimize the mixes to achieve the best results. The properties considered were the durability of acid attack resistance (H₂SO₄ attack), salt attack resistance (MgSO₄ attack), and water absorption. The heat resistance considered was weight reduction and residual compressive strength after heating the samples at a 200 °C and 400 °C. The results findings showed that CR and CCR negatively affect the acid and salt resistance of the SCC. Furthermore, CR negatively affects the heat resistance of the SCC, while CCR slightly improved it at 200 °C. The models developed using RSM were significant with high degrees of correlation and predictability. The optimum properties achieved 2.9% CR as a fine aggregate replacement and 5.5% CCR as a cement replacement. The developed models can predict the durability performance of SCC mixes in terms of acid and salt attack resistance and the effects of elevated temperatures using CR, CCR, and fly ash as the variables. This will reduce the need for carrying out experimental work, thereby reducing cost and time.

Nano-lubricant machining of Aluminum 8112 alloy is the art of sustainable manufacturing of mechanical components used for defense technology and aerospace application. However, machining aluminum alloys generates excess heat, which tends to increase the cutting force (F.C.), due to the material adhesion of the workpiece on the cutting tool. The challenge has drawn researchers’ attention to introducing nano-lubrication processes. This study focused on the comparative assessment of eco-friendly vegetable oil-based-TiO₂ and MWCNTs nano-lubricant on cutting force during the machining of the Aluminum 8112 alloy. Nanoparticles were implemented on the base oil using an ultrasonic vibrator and magnetic stirrer before the application in the machining, via the minimum quantity lubrication process. Quadratic central composite designs were employed to carry out the experiment, using five factors at five levels, having experimental runs of 50. The input parameters are helix angle (H.A.), spindle speed (S.S.), axial depth of cut (ADOC), feed rate (F.R.), and length of cut (LOC). The results show that the application of the nanoparticle increases the performance of the vegetable oil on the cutting force. TiO₂ nano-lubricant reduces the cutting force by 0.26%, compared with the MWCNTs, and 6% compared with the vegetable oil. Furthermore, the MWCNT nano-lubricant reduces the cutting force by 5% compared with the vegetable oil lubrication environment.