Malaysian Journal on Composites Science and Manufacturing

Numerical Investigation of Injection Pressure Effect on the Performance and Emission of a Diesel Engine Fueled with Butanol-Diesel Blends

Md. Radwanul Kabir — 2025-03-20

Globally, fossil-based resources are becoming increasingly scarce as the demand for energy from power-producing systems rises. Diesel engines are a popular and efficient source of electricity, but different national and international organizations have imposed limits on diesel emissions. Reducing emissions and boosting performance are typical operations in diesel engines. ANSYS FORTE code was used to generate a thorough numerical configuration. Analyses were conducted on a single-cylinder, four-stroke, direct-injection diesel Cummins N-14 test engine setup running on a 40 percent butanol-diesel blend with injection pressure ranging from 400 bar to 1600 bar at constant speed conditions to determine its performance metrics (i.e. Thermal Efficiency & Specific Fuel Consumption), combustion attributes (i.e. In-cylinder Pressure, In-cylinder Temperature & Apparent Heat Release Rate), and emissions characteristics (i.e. CO emission, Nox emission & Soot emission). In general, as injection pressure was raised, thermal efficiency, CO emissions, and soot emissions all improved, while in-cylinder temperature, in-cylinder pressure & NOx emissions rose progressively. For instance, for 1400 bar fuel injection pressure, maximum in-cylinder pressure and in-cylinder temperature were found, around 18.6 bar and 1650 K, respectively, whereas injection started at a 22-degree crank angle before top dead center (bTDC). The optimal injection pressure for internal combustion engines was determined by considering both emissions and performance. The results indicated that an injection pressure near 800 bar led to the following outcomes: an in-cylinder temperature of approximately 1520 K, an in-cylinder pressure of around 17.5 bar, a thermal efficiency of 32.50%, and a specific fuel consumption of approximately 292 g/KW-h. Additionally, implementing a 90%-10% split injection method with equal crank angle duration (CAD) resulted in an average reduction of 4-6% in NOx emissions.

Effect of Metal Filler on the Welded Joint of X70 Steel Joined to Duplex Stainless Steel by Gas Arc Welding

Zakaria Boumerzoug — 2025-03-20

This study investigates the effects of using two different metal fillers on the microstructure, corrosion resistance, and mechanical properties of a duplex stainless steel and X70 steel welded joint, performed using the Gas Tungsten Arc Welding (GTAW) process. The electrodes employed were ER2209 and ER70S. The research aims to assess the feasibility of welding dissimilar steels with these two electrodes. Three weld passes were conducted using the different electrodes, followed by characterization of the welded joint's microstructure and evaluation of its mechanical properties. The primary characterization techniques included optical microscopy, scanning electron microscopy, Electron Backscatter Diffraction (EBSD), corrosion testing, Vickers microhardness, and tensile testing. The welded joint exhibited no visible defects, and using two electrodes increased the hardness, particularly in the fusion zone, where it reached 290 HV. Microscopic analysis revealed a solidification microstructure in the fusion zone. The welded joint demonstrated intermediate corrosion resistance between the two base steels (duplex stainless steel and X70). At the same time, its tensile strength was also intermediate, achieving more than 96% of the nominal tensile strength of duplex stainless steel. This approach of bonding dissimilar steels offers a potential solution for substituting one steel type with another in automotive structures, enhancing their resistance and reducing production costs.

Preparation of Antifouling Composite Coating for Rubber. Part 1: Manufacturing and Laboratory Testing

Thanh Nguyen Trung — 2025-03-20

This article introduces results of investigations on Cu₂O concentration on release rate of antifouling composite coating for rubber, effects of fineness on ability to release Cu₂O of paint (fineness of paint increases, Cu₂O release speed of composite coating decreases), effects of period from composite coating preparation to start testing on ability of Cu₂O release. Besides, effects of anti-UV additive on ability of composite coating to withstand from UV-thermo-humidity complex was also investigated. Results show that Cu₂O concentration is 25 weight percent (wt. %), fineness of paint is 75-80 µm are suitable, period from composite coating preparation to time for being used is about 5 days for the best antifouling grade while ensuring mechanical properties of composite coating. Anti-UV additive of 1 wt. % is suitable for antifouling composite coating for rubber.

Design and Fabrication of a Quick Action Medicine Dispensary

Alvee Jawad Hamid — 2025-03-30

One of the major concerns in the medication process is ensuring that patients take the right medicine at the right time. This issue often necessitates additional assistance, especially for patients who need to take multiple medications multiple times a day, as it can be challenging to remember and manage all medications efficiently. Extensive research has been conducted on developing automated medicine dispensaries to aid patients in this process. However, most existing solutions are either theoretical design concepts or limited to dispensing medicines in batches only. This research aimed to design and fabricate an automated and universal medicine dispensary that addresses the challenges of accessibility and the complexities of scheduled medication intake. This dispensary also provides the capability to dispense medicines both in batches and as single units, according to user requirements. A comprehensive design concept was developed, incorporating essential features such as medicine storage, a user interface, a dispensing mechanism, and a timer system. The prototype was constructed using polyvinyl chloride (PVC) and polylactic acid (PLA), and its functionality was evaluated. The evaluation demonstrated that the automated dispensary could store multiple types of medicines. It featured a compact and user-friendly interface, an accurate alarm system for reminding patients of their scheduled medication times, and a precise dispensing mechanism capable of dispensing medicines discretely and in batches. This automated medicine dispensary, leveraging composite materials like PVC and PLA, has the potential to streamline medication intake processes, enhance healthcare services and revolutionize next-generation medicine.

Taguchi Method-Based Optimization of Single-Pass Abrasive Waterjet Cutting of Thick Aluminium

Hanizam Hashim — 2025-03-30

Cutting force attenuation in AWJ induces surface defects (high Ra, large theta) in metals and delamination in composites, especially in thick sections that limiting industrial adoption and requiring post-processing. A robust Taguchi experimental design was employed to optimize AWJ cutting parameters to minimize these issues when cutting thick aluminium blocks. An L8 orthogonal array with three factors; waterjet pressure (WP), stand-off distance (SOD), and traverse speed (TS), each at two levels, was used and analyzed via Minitab software. Other parameters remained constant: nozzle diameter (1.0 mm), abrasive size (80 mesh), and abrasive flow rate (0.3 kg/min). Traverse speed was found to be the most critical factor affecting Ra and theta, though waterjet pressure and stand-off distance also had significant impacts. The optimal parameters, higher waterjet pressure (315 MPa), lower traverse speed (38 mm/min), and lower stand-off distance (3 mm), yielded the best results for both Ra (4.2 µm) and theta (1.24°). In conclusion, the interaction of optimized AWJ parameters enhances kinetic energy and momentum transfer, improving material removal efficiency and cutting surface quality. The study systematically evaluates critical abrasive waterjet parameters to optimize cutting strategies, demonstrating applicability for thick aluminium and diverse material types.

Effect of Sodium Chloride-Assisted Heat Treatment on Virgin and Recycled PLA Filaments in FDM 3D Printing

Nurul Izzati Zaidi — 2025-03-30

Polylactic acid (PLA) is widely employed in Fused Deposition Modeling (FDM) owing to its biodegradability and ease of processing. Nonetheless, both virgin and recycled forms of PLA exhibit susceptibility to mechanical degradation, particularly under thermal stress. This study investigates the influence of sodium chloride-assisted post-processing heat treatment on the tensile properties of virgin PLA (vPLA), commercial recycled PLA (c-rPLA), and self-extruded recycled PLA (se-rPLA). Sodium chloride, used in the powder bed, helps regulate heat distribution during thermal treatment, improving tensile strength by reducing thermal degradation. Specimens were subjected to thermal treatment in a sodium chloride powder bed at 70°C, 85°C, and 100°C for 90 minutes. Tensile testing, conducted in accordance with ASTM D638, revealed strength improvements ranging from 3–6% for vPLA and 14–18% for c-rPLA. However, a tensile strength reduction of approximately 36% was observed in se-rPLA after heat treatment at 85°C, likely due to thermal sensitivity or material degradation. These findings suggest that while heat treatment can enhance the performance of commercial recycled and virgin PLA, its effectiveness for self-extruded PLA depends heavily on prior processing conditions. The study highlights the importance of carefully tailoring thermal post-processing protocols to the specific characteristics of recycled materials to support their use in sustainable 3D printing.

Multi-Criteria Decision Analysis for Optimal Material Selection in Unmanned Aerial Vehicle Manufacturing

Mohd Suhaimi Omar — 2025-03-30

Unmanned Aerial Vehicles or UAVs were pilotless aircraft or aircraft with minimum human interaction. UAVs material and structure were critical aspects to consider throughout the development phase. UAVs were utilized in both the military and the civilian sector. However, because of this diversity of uses, their materials and structure differed due to the requirements and resilience needed for those uses. Due to the different materials used in the other development of UAVs, this study aimed to study the appropriate structure material for the development of UAVs. Moreover, this study investigated the process of preparing the body structure of the selected material from developed UAVs particularly for military specifications. Additionally, this study analyzed the best approach that was used to reduce the maximum take-off weight. This study focused on the best structure from the successful product of UAVs from the selected company. This case study was performed to investigate what had been practiced and for further analysis while analytical hierarchy process (AHP) and quality function deployment (QFD) were used as research methods to perform the multi-criteria decision analysis. Carbon fiber was selected as suitable material for wing and propellor while fiberglass composite was identified as suitable material for tail and body of UAVs. This study provided a strong basis for future UAV development, this all-encompassing strategy sought to create an organized framework for decision-making that synchronized technical specifications with operational and customer objectives.

Mechanical Performance of Recycled Polypropylene Composites Reinforced with Activated Carbon-Treated Clay as Concrete Aggregates

Najatul Athirah Musa — 2025-03-30

The growing concern over plastic waste and the depletion of natural aggregates has spurred interest in sustainable construction materials. This study examines the mechanical and morphological performance of recycled polypropylene (rPP) composites reinforced with activated carbon (AC)-treated clay for use as lightweight concrete aggregates. The novelty lies in the hybrid filler system combining clay and AC within a recycled polymer matrix; an approach rarely explored for structural concrete applications. Composites were fabricated using a single-screw extruder at 185°C and 50 rpm, incorporating AC at 1, 3, 7, and 15 wt%. Mechanical testing revealed that 3 wt% AC achieved the highest tensile strength due to enhanced filler dispersion and interfacial bonding, while 15 wt% AC increased stiffness but reduced elongation due to agglomeration and brittleness. The highest yield strength at 7 wt% AC suggests a percolation threshold effect, improving load transfer efficiency. FESEM and EDX analyses confirmed better filler distribution and matrix-filler interaction at lower AC contents, aligning with mechanical results. These findings highlight rPP/clay/AC composites as eco-friendly, lightweight concrete aggregate alternatives with a balance of strength, stiffness, and flexibility. This study underscores the environmental benefits of repurposing plastic and carbon-based waste while recommending further investigation into their long-term durability and real-world performance.

Parametric Study and Characterization of Nitrogen-Doped Carbon Quantum Dots Synthesized via Hydrothermal Method

Nurul Ayunni Abdul Latif — 2025-03-30

Carbon quantum dots (CQDs) are zero-dimensional nanomaterials known for their chemical stability, water dispersibility, low cytotoxicity, small size, biocompatibility, and photoluminescence. This study reports the synthesis of nitrogen-doped CQDs (N-CQDs) using urea and citric acid derived from calamansi lime via a simplified hydrothermal method. A 2³ full factorial Design of Experiments (DOE) optimized synthesis parameters: temperature, reaction time, and precursor ratio. Optimal conditions were 140°C, 2 hours, and a 1:1 precursor ratio. The resulting N-CQDs exhibited strong photoluminescence, excellent colloidal stability, and particle sizes ranging from 5 to 10 nm. Tauc plot analysis indicated bandgap energies up to 5.81 eV, influenced by particle size and quantum confinement. UV-Vis and FTIR spectroscopy confirmed the absorption behavior and the presence of nitrogen and oxygen functional groups, respectively, while photoluminescence measurements showed intense emission. FESEM, TEM, and EDX analyses revealed uniform spherical morphology and confirmed successful nitrogen doping. The tunable surface chemistry and optical properties of N-CQDs make them promising for bioimaging, sensing, and optoelectronics applications. The sustainable, cost-effective hydrothermal synthesis method supports scalable production for use as functional fillers in nanocomposites.