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An increase in human population correlates with an increase in demand for energy. Coal has been a vital energy source for human populations for millennia, where it has played a major role in various industries, especially in the thermal-based industries. Coal is found in all three geographical provinces of Malaysia: Peninsular Malaysia, Sarawak, and Sabah. However, at most, the widespread and abundant occurrences of coal are found in Sarawak, especially in Mukah. The age of the coal deposits found in Mukah has instigated research that focuses mainly on the characterization of minerals and other properties in the coal, where those findings could be used to propose coal usage in other types of industries. To achieve those objectives, this research starts with a theoretical approach by discussing the coalification process, followed by understanding the types of coal produced from this process. Basic coal analysis, visual inspection, proximate analysis, XRD, SEM-EDX, and FTIR analysis were done to achieve all the objectives. At the end of the research, it was found that the Mukah coal sample is denser and has a higher gold content compared to the commercial coal sample. It was seen that the commercial coal possessed a high caloric value compared to the Mukah coal. This may be due to the high moisture and silicone content in the coal sample as it is mined directly from the earth. Overall, the Mukah coal sample could be used for other industries, like the fertilizer industry, rather than just being used to generate electricity by burning.

Types of reinforcements in Metal Matrix Composite (MMC) are essential to form a better MMC due to the bonding element to the based matrix. This research was carried out based on the recycling of aluminium alloy AA7075 reinforced rice husk silica (natural waste fibres) as MMC. Solid state technique was used to examine the effect of rice husk silica as a reinforcement agent in MMCs. This technique remarkably lower operation costs and resources compared to conventional cast recycling. Recycled aluminium chip AA7075 with the addition of composition as-received untreated and treated rice husk silica (2.5, 5, 7.5, 10, and 12.5 wt%) were used. Treated rice husk was soaked in hydrochloric acid to fasten the burning process at temperatures of 700 and 1000°C. MMC samples were prepared using a cold compaction method by setting of load compaction of 9 tons for 20 minutes. Then, the MMC samples were sintered at a temperature of 552°C. Mechanical properties of MMC were obtained from hardness and compression tests, while optical microscope (OM) and scanning electron microscopy (SEM) were used for microstructural analysis of MMC samples. For mechanical properties, the hardness of MMC was higher at 10 wt% rice husk silica, i.e., 65.93 Hv for untreated, and 69.52 Hv for treated rice husk. These results were based on rice husk silica that burned at 700℃. It found that aluminium chip sample without reinforcement was 53.49 Hv, which is lower than samples at 10 wt% of rice husk silica. For the compressive strength, silica burned at 700℃ indicated rice husk silica at 5 wt% obtained high strength of MMC with 333.63 MPa for untreated, and 322.52 MPa for treated rice husk silica. In comparison, aluminium chip without a reinforcement sample was found to lower strength with 290.47 MPa. Based on this research, the reinforcement of rice husk silica burned at 700℃ has better properties of MMC compared to rice husk silica burned at 1000℃.

In this paper, the effect of imperfections on electrical and macro hardness property of a novel experimental high-Zn Al-Zn-Mg-Cu alloys produced from recycled beverage can was investigated with the aim of correlating hardness with conductivity using ANOVA. Alloys were observed in the as cast (AC), annealed (O), natural aged (T4) and artificial aged (T6) conditions. Heat treatments supported the formation of hardening precipitates like the Al2.06Fe4, α-AlFeSi, Al7Cu2Fe, θ(Al2Cu), β-AlFeSi and  MgZn2 phases. Imperfections inform of voids and contaminants are by-products of recycled aluminium and casting route. Peak obtainable hardness of 122.94 Hv in the T6 condition was observed in an alloy of Al-5.0 Zn-1.5 Mg- 0.35 Cu. The same alloy’s conductivity is 3.676 ´ 107 S/m. The least hardness of 38.16 Hv and conductivity of 3.533 ´ 107 S/m is credited to an alloy of Al- 5.0 Zn-1.00 Mg-0.35 Cu in the O condition. The relationship between hardness and conductivity is nonlinear. Models developed to predict the hardness of this experimental alloys fits all the variables and covers the AC, O, T4 and T6 respectively. The need for further investigation on the imperfections, optimization of mechanical properties and additional mechanical properties investigation is required.

The transport industry is one of the highest consumers of aluminium alloys. However, the quest for new and cheaper aluminium with properties comparable to the contenders has remain in the research domain for sometimes. Even at that, the literature is dearth of clear ideas on conversion of the huge RBCs to X7475 experimental alloys. In furtherance to the fabrication of a new 7xxx (Al-4-5Zn-1.5Mg-1.0Mn-0.35Cu) alloy from Recycled Beverage Cans (RBCs), the effect of annealing temperature (350 oC, 380 oC and 413 oC) and artificial ageing time (6, 10.5 and 15 hours) on the ultimate tensile strength (UTS) and elongation (e) were reported. Nine samples (S1-S9) of experimental alloys were fabricated and subjected to tensile tests, SEM/EDX and XRD analysis. Secondary phases like MgZn2, Cu2Mg precipitates as observed in the XRD supported an improved UTS. The elemental analysis revealed the presence of alloying compositions. An alloy fabricated using Al-5Zn-1.5Mg-1.0Mn-0.35Cu (S9), artificially aged at 6 h and annealed at 413 oC had the highest UTS of 362.2 MPa and an elongation of 3.09 mm (15.45 %). The result demonstrated that a new X7475 alloy was fabricated from RBCs with comparable mechanical properties with alloys fabricated using pure aluminium.  &nbsp

The use of low cost metal matrix composites (MMC) is increasing rapidly in various engineering fields because of their better mechanical properties. The effects of recycled aluminium chips AA7075 with untreated rice husk ash (URHA) and treated rice husk ash (TRHA) on physical properties were investigated. Recycled aluminium chip AA7075 was reinforced with untreated and treated rice husk ash i.e., 2.5 wt.%, 5 wt.%, 7.5 wt.%, 10 wt.% and 12.5 wt.%. Density, apparent porosity, water absorption, micro-hardness and microstructures analysis of the metal matrix composites samples were examined in current study. The density for metal matrix composites increase up to 5 wt.% of rice husk ash, and then decreased with increasing mass fraction of rice husk ash. However, the densities for treated rice husk ash slightly higher than untreated rice husk ash. Porosity and water absorption of metal matrix composites were consistently increase at increasing mass fraction of rice husk ash. The hardness of chip AA7075 has improved with increasing the composition of rice husk ash from 53.49 Hv to 65.93 Hv for untreated rice husk ash and 69.56 Hv for treated rice husk ash at addition 10 wt.%. The microstructures of metal matrix composites were found random distribution and non-homogeneous compared to fully chip AA7075.

The effect of water (as a primary plasticiser) content on the chemical structure and mechanical properties of thermoplastic tapioca starch (TPTS) film was evaluated. The TPTS films were produced by tape casting technique through mixtures of fixed amount of glycerol and varied contents of tapioca starch and water. There was observed increase in hydrogen bonding interaction between starch and water molecules depicted by the downward shift between 3303-3281 cm-1. The excessive amount of water loading portrayed increase in crystallinity due to free volume movement of the starch particles. The changes in water loading also showed variation in the tensile strength and elongation at break of the TPTS films. This observation is because of the dependence of mobility of polysaccharide plastics on the water content in the premix. Therefore, starch forms entanglements with the plasticisers to form a flexible film.

The heterogeneous nature of microstructure in most as-cast alloys has created the unique properties for an ally before heat treatments. The scanty nature of scholarly articles on the effect of heat treatments on the hardness of new alloys produced from recycled aluminium alloys prompts this investigation. In this work, we upgraded from 3 series to 7 series alloys to form a new material. Previous attempts were also silent on the Alcao Green Letter specifications of the 7 series alloys, hence producing a 7475 alloy that may not be within the Alcao specifications. This paper presents the result of preliminary studies on new experimental X7475 Al-alloy that was produced per Alcoa Green Letter specifications, with variations of Zn (4.0 - 5.0 wt.%), Mg (1.00 - 1.50 wt.%) and Mn (0.025 - 0.075 wt.%), then subjected to microhardness probe under a load of 490.3mN (0.05Hv) and 10sec duration after isothermal and isochronous “O”, T4 and T6 heat treatments. Heating and cooling rates were controlled during heat treatment processes to investigate the effects on the formation of the MgZn2 and other precipitates on the mechanical properties of the alloy. Peak obtainable hardness value of 140.45 Hv and 134.32 Hv are attained within the T6 and T4 conditions in an alloy of 4% and 5% Zn respectively. The increase in wt.% of Zn favours mechanical properties while reverse is the case for Manganese. This result is an indication of the load bearing capacity of our alloy. It has also demonstrated the success in upgrading the 3 series to 7 series alloys from secondary materials. However, the result could be improved on after composition, heat treatments and production route optimization.

Silica is an inexhaustible resource on earth. It can be found in food-based natural resources. The natural tendency of silica mainly is to contribute to the strength and the hardness of the ceramic material. This paper investigates the hardness formed in ceramic filtration membrane made by amorphous and crystalline silica from rice husk. Four samples from this material were studied based on unwashed and washed material with chemical, namely, crystalline silica treated with chemical (CS1), crystalline silica untreated with chemical (CS2), amorphous silica treated with chemical (AS1) and amorphous silica untreated with chemical (AS2). To acquire the silica phases, the rice husk was experienced to combustion process at 700ºC and 1000ºC for 2 hours. The properties of the silica were obtained by using Scanning electron microscopy (SEM) and x-ray diffractometer (XRD) while the value of the hardness was tested by using microhardness tester machine. As a result from SEM both samples of AS1 and AS2 produced an irregular, crinkled, or grainy surface of silica and for sample CS1 and CS2 produced were flushed, unwrinkled and planar surface. For the high hardness value, crystalline silica treated with chemical (CS1) sample was obtained with 171.0.

The main function of bone repair is to adjust the fractured bone in order to allow fast back healing and complete functionality of the injured bone part. Metallic implants have many problems such as stress shield, palpation and temperature sensitivity etc. Consequently, biodegradable bioactive composite gained interest as they avoid elimination and increase bone renovation due to lack of stress shielding effect. In the current paper, nanobiocomposite consisting of polylactic acid (biodegradable) (PLA) and nano hydroxyapatite (bioactive) (n-HAP) extracted from bovine bone was fabricated through melt mixing and injection moulding technique for biomedical application. Partially biogenic n-HAP was obtained from bovine bone by hydrothermal and calcination processes. Physicomechanical properties of neat PLA and PLA/n-HAP nanobiocomposite are evaluated using universal testing machine (UTM) and scanning electron microscopy (SEM). The results revealed that the higher n-HAP loading (1-5 wt%) in PLA matrix, the lower the tensile strength of nanobiocomposite. PLA/n-HAP with 1 wt% loading exhibits tensile strength potential for bone implant application and can be promising biomedical materials for orthopedic applications.

This study focused on the Gombe fireclay that is under-utilized despite its abundance as essential ingredient for the manufacture of refractories. Hence, the clay was studied and appraised for its appropriateness for the manufacture of refractory fireclay brick. The physical, mechanical and thermal properties were investigated according to ASTM Standard Test Methods for fireclay refractories. Its chemical composition result indicated that it belongs to alumino-silicate group. Its refractoriness proved that it is a high duty (siliceous) refractory brick with refractoriness of 1621 °C equivalent to PCE Segar cone 26. It was sintered at varied sintering temperatures of 900 °C, 1000 °C, 1200 °C and 1100 °C. The sintering temperature of 1200 °C was found to be the best which significantly influenced the mechanical properties. The cold crushing strength was 15.37 MPa, apparent porosity was 24.52%, firing shrinkage was 7.5% and the bulk density was 1.9 g/cm3. The experimental result proved that the clay was suitable for production of refractory fireclay brick for furnace lining.

This paper presents the study of the features of the rice husk and to investigate the presence of silica in the rice husk. To obtain the pure silica, the rice husk was firstly washed and went through chemical treatment, prior to combustion. The combustion process was conducted at temperature of 700℃ for 2 hours. The rice husk ash obtained was studied and has been named as C3. The characteristics of C3 samples can be acquired by using scanning electron microscopy (SEM), x-ray diffractometer (XRD) and thermogravimetric analysis (TGA). The SEM images showed the material was in agglomeration. The silica content of C3 was observed to be 89.85% using EDS. The thermal properties of the C3 also was performed using TGA as the change with temperature up to 1000℃ with heating rate of 5℃/min. As from the result, the energy of organic compound lose at 700℃ was 0.0141mg/min and at 1000℃ was 0.00217 mg/min.

Cermets (ceramic-metal) materials have been popular for wear and corrosion application due to their ability to withstand both conditions. In current work, cermets tungsten carbide-nickel (WC-Ni) composite coating has been deposited using direct current (DC) electrodeposition in Watt’s bath on mild steel. The current density were varied at 0.08 Acm-2 , 0.14 Acm-2 and 0.20 Acm-2 while others parameter i.e. bath temperature and stirring rate were remain constant. Three carbide concentrations were used that are 15 g/l, 20 g/l and 25g/l. This work is focusing on determining the effect of current density and carbide concentration to the wear and corrosion behaviour of WC-Ni cermet coating. The surface morphology, microstructure and elemental composition were analysed using scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS). The wear and corrosion behaviour were evaluated using weight loss methods and three electrode electrochemical tests respectively. The abrasive wear was done against 800 grit silicon carbide paper. While for corrosion test, two types of electrolytes that were used are 0.5 M sulphuric acid and 3g/l sodium chloride at room temperature. The micro-hardness of the coating was analysed using Vickers micro-hardness tester with 100g load. It is found that, the wear resistance increases with increasing of carbide content and current density. The corrosion resistance was also increase with increasing of carbide content. For current density, it is slightly decrease of corrosion resistance after deposition at 0.20 Acm-2 due to uneven distribution of carbide. The hardness of the cermet coatings were increase with increasing of carbide content and current density. It can be concluded that with 25g/l carbide and at 0.14 Acm-2 current density shows the optimum combination to achieve high wear and corrosion resistance.

This study focused on the thermal propertiesof the Kpata fireclay in order to look into its refractoriness. Thermogravimetry (TGA), differential thermal analysis (DTA) and thermal conductivity tests were carried out to analyse the fireclay’s thermal properties. The fireclay was also compacted and fired at various firing temperatures. The TGA result indicated that there was material weight loss at 0.26 mg, 0.56 mg and 1.74 mg at temperatures of 90.53 °C, 425.12 °C and 578.87 °C respectively. The DTA revealed that there were exothermic and endothermic material reactions.The Kpata fireclay also had a thermal conductivity of 0.33 K (W/m.k). Apparent porosity of fired fireclay showed that the porosity was reduced as firing temperature increased. These conditions indicated that Kpata fireclay has the possibility in refractory and insulating applications.

Nanocomposite of polypropylene (PP) was made by melt intercalation technique with nanokaolin. Kaolin particles were modified with urea by intercalation to produce nanokaolin. Structural and morphological analyses of polypropylene/kaolin nanocomposite was investigated by Fourier Transform Infrared (FT-IR) spectroscopy and Field Scanning Electron Microscopy (FESEM). The interaction of FT-IR confirms hydrogen bonds formed between urea molecules and the inner surface of kaolin layers. It also gives evidence that kaolin was dramatically delaminated into nano scale by intercalation activity. Whereas, FESEM shows kaolin particles were homogeneously dispersed into the PP matrix.

The mineral and elemental composition, crystal structure and particle size distribution of kaolin clays have been determined to ascertain its industrial significance. The mineral composition is evaluated by X- Ray Fluorescence (XRF), crystalline structure by X-Ray Diffraction (XRD) and particle size distribution using low angle laser light scattering (LALLS) technique. The results shows the presence of eight elements expressed in percentages in form of their oxides as: SiO2, Al2O3, Fe2O3, MgO, CaO, K2O, TiO2 and P2O5. Five crystalline structures are revealed by XRD result. The particle size distribution shows that kaolin particles are mainly in the range of 25–35 µm, while few particles have size distribution varied between 0.4–0.75 μm. The report is found to be in agreement with other researchers.

Raw kaolin was refluxed by sulphuric acid in variable concentrations of 2 M, 4 M, 6 M and 8 M. The morphology and elemental compositions of the acid-leached kaolin were analyse by Field Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray analysis (EDX) respectively. The disintegration and leaching of Al3+ ions of the clay are determined by FESEM studies. The acid treatment increases the silicon content and decreases aluminium content as revealed by EDX analysis. The leaching of Al3+ ions increases with gradual increase in concentration of the acid. Therefore, kaolin reflux with acid at lower strength (2 M and 4 M) are more dispersed and more industrially useful than that which is treated at higher acid strength.