Abdullah Wagiman

Non-melted recycling of aluminium chips via hot extrusion is an alternative technique towards sustainable manufacturing. The process prior to hot extrusion is crucial in achieving free-microvoid extrudates, which were caused by air trapped in chip-based feedstocks. In this work, heat treatment was performed on the chips before they were compacted into the feedstock. The effect of annealing temperature, time and compaction pressure on density was investigated. The experiment is conducted using a 2³ factorial design, and an ANOVA is used to identify the main parameters. Upon compaction, feedstocks were visually inspected and tested. The results indicate that parameters such as compaction pressure, annealing temperature, and annealing time are statistically significant. The main parameter is the compaction pressure, followed by the annealing temperature, the interaction between the annealing temperature and the annealing time, and the annealing time. At high annealing temperatures, annealing time does not have a significant effect on density. However, at low annealing temperatures, annealing time plays a significant role. Feedstock made from the non-annealed chips has lower relative density compared to annealed chips. Furthermore, the higher the density of the feedstock, the fewer voids will appear on the surface of the product.

This paper reported on the design and performance evaluation of a hybrid photovoltaic thermal solar dehydrator. The dehydrator is designed to suit the needs of household users and small industries and works using a hot air mechanism. The design process commenced with the initial sketches to collect related ideas and design concepts. The design was then proceeded to concept evaluation through a decision matrix to select the best option. The final design was then converted via computer-aided design (CAD), SolidWorks 2021 to a 3D model and fabricated into a full-scale prototype. The drying performance of the dehydrator on food was evaluated and compared with traditional drying under the meteorological conditions of Panchor, Muar, Malaysia. Heat accumulated inside the dehydrator resulted in a temperature of 44.1 degrees Celsius which is 20 % higher than the ambient temperature. The performance analysis demonstrated that the drying speed of a hybrid solar dehydrator is moderately slower than traditional drying, but it provided a more hygienic drying environment and preserved the color and nutrition value of food products.

Solid state recycling of aluminium via hot extrusion is a sustainable technique. The process performed before hot extrusion plays a vital role on the extrudate properties. In this study, the effect of naturally and thermally formed in-situ alumina on the extrudate density were investigated. Fours type of material identified as a solid as-received, non-treated recycle chip, 300 0C thermally treated recycle chip and 500 0C thermally treated recycle chip were prepared for the experiment. Prior to extrusion, the recycle chips were compacted into a chip-based billet, preheated and immediately extruded into a semi-finished product. The density test performed on the chip-based extrudate found that the type of chips influenced the density. The chip-based extrudate made of 300 0C and 500 0C thermally treated chips resulted in higher density than solid as-received and non-treated chips. Chip-based extrudate produced from 500 0C thermally treated chips resulted in density of 2724 kg/m3, which is the highest among the specimen. This density value was 0.7 % higher compared to the solid as-received extrudate. Microstructure examination on the cross-section revealed the alumina entrapped in the chip-based extrudate. The alumina entrapped in 500 0C thermally treated chips specimen was more prone than the non-treated and 300 0C thermally-treated chips. This finding explains the variation in the extrudate density.

Solid-state recycling is a sustainable technique for recycling aluminium scrap, and the process before recycling is essential to control the physical properties of the product. In this work, the effect of the thermally-treated chips on the extrudate density was investigated. The aluminium chips were thermally-treated to enrich the alumina layer and reduce compaction pressure during chips compaction before recycled using direct hot extrusion. The chips that were transformed into compacted billets were extruded directly without melting and conducted according to 2⁴ full factorial experimental design. The density test on the recycle extrudate found that the density variation ranged from 2724 to 2983 kg/m³. The ANOVA result showed that all factors investigated were statistically significant. The most significant factor was the preheating temperature, followed by extrusion ratio, chip treatment temperature, chip treatment time, and the interaction of chip treatment-time–extrusion ratio. The predictive model suggested by the ANOVA is useful to predict the density with 1% error. Microstructure examination revealed the presence of alumina entrapped in the recycle extrudate, in which thermal-treated chips contained more alumina than that of the untreated chips. The result indicated that the thermal treatment performed on the chips had enriched the in-situ alumina, affecting the density of the recycle extrudate.

Road condition in term of road surface condition depends on the subgrade soil strength. Therefore, a weak subgrade condition requires improvements in stabilization. Soil stabilization is the alteration of one or more geotechnical properties to create an improved soil material possessing the desired engineering properties. The main purpose of the soil stabilization is to increase the shear strength of an existing ground condition to enhance its load-bearing capacity, achieve a desired improved permeability and enhance the durability of the soil to resistance to the process of weathering, and traffic usage among others. Three method in soil stabilization considered in this study are chemical admixture, mechanical and geosynthetics methods. The difference in soil stabilization methods depends on the different road surface conditions. Road condition with weakness subgrade is more appropriate and economical in used stabilization chemical method. In this paper, discussing the road condition requires the ground improvement through soil stabilization

Innovations were conducted continuously to create sustainable asphalt modifier. In this research it is focused on the investigation work of the asphalt binder modified properties with different percentages of one different micro material. This material is Parit Nipah Peat. The investigation is about the physical properties of asphalt binders modified with Parit Nipah Peat PNpt.M.A. PNpt leads to make a lot of changes in internal and external of the samples that checked via penetration test, ductility test, and Scanning Electron Microscopic. The Parit Nipah Peat was added to the original binder with a high shear blender then used at 1500 rpm to mix the PNpt with the binder. Three (3) different percentages were mixed by weight of binder to modify the asphalt binder with the binder at 0, 3%, 5% and 7%. This material has a high ability to distribution with asphalt, appears to be plain and homogeneous and different structure after blended with bitumen. The physical property of modified binders enhanced the binder properties, as the results of penetration test, ductility test and distribution inside the binder showed that. Adding a different concentration of PNpt to base binder had significant effects of high resistant changing volume and increased hardness.

Produced Profiles by direct recycling of aluminum chips in hot extrusion process were achieved by temperature related parameters using preheating temperature 450 °C, 500 °C, and 550 °C for duration 1 hour, 2 hours, and 3 hours preheating time. By using Design of Experiments (DOE) procedure with full factorial design and three center points analysis, the results showed that the preheating temperature factor is more important to be controlled rather than the preheating duration and increase of temperature conducted to the high tensile strength. The profiles extruded at 550 °C and 3 hours’ duration had obtained the optimum condition to get the maximum tensile strength. The influence of parameters of hot extrusion process on fracture surfaces of the recycled samples was also investigated and discussed.

Direct hot extrusion is an alternative process for recycling aluminium without melting the scrap. It utilizes low energy and is environmental friendly. This paper reports the microhardness and microstructure of aluminium alloy chips when subjected to various settings of preheating temperature and preheating time in hot extrusion process. Three values of preheating temperature are taken as 450 °C, 500 °C, and 550 °C. On the other hand, three values of preheating time were chosen (1 h, 2 h, 3 h). The influences of the process parameters (preheating temperature and time) are analyzed using design of experiments approach whereby full factorial design with center point analysis are adopted. The total runs are 11 and they comprise of two factors of full factorial design with 3 center points. The responses are microhardness and microstructure. The results show that microhardness increases with the decrease of the preheating temperature. The results also show that the preheating temperature is more important to be controlled rather than the preheating time in microhardness analyses. The profile extrudes at 450 °C and 1 hour has gained the optimum microhardness and it can be concluded that setting temperature at 550 °C for 3 hours results in the highest responses for average grain sizes in analysis of microstructure.