Volume 37 (08) November 2025

The conversion of solar radiation into thermal energy relies heavenly on heat transfer fluid for heat transfer and energy storage. Bio-oil-based nanofluids are considered renewable, efficient, and environmentally friendly alternatives to conventional heat transfer fluids. However, issues regarding thermal stability, long-term stability, and the development of binary nanocomposites to improve the performance of bio-oil-based heat transfer fluids remain unsolved.This study presents a novel bio-oil-based binary nanofluid derived from palm kernel oil base fluid and binary Al₂ O₃-TiO₂ nanoparticles. The characterization, nanoparticle functionalization, sedimentation, and zeta potential analysis were used to evaluate the nanoparticles, resulting nanofluid properties, and stability. Results from thermophysical measurements show the binary nanofluid’s thermal conductivity significantly increases by 34.6% at 60oC temperature for 0.3wt%. The viscosity of the nanofluid decreases with increasing temperature. The highest percentage decrease recorded at 0.1wt% is 34.3%. The reduction in specific heat due to nanoparticle addition is 7.73%, 7.34%, 7.08%, and 8.37% lower than the base PKO. The density of the pure PKO decreases by 2.48% from 30°C to 60°C while 0.3wt% decreases by 2.89%. The work also provided an empirical correlation to estimate the thermal conductivity and viscosity of Al₂ O₃-TiO/PKO based on experimental data. The correlated results demostrated that the prediction model performs well. The overall results demonstrate a significant increase in the thermophysical properties of the developed Bio-oil-based heat transfer fluid, underscoring its superior heat transfer properties.This improvement paves the way for more efficient and sustainable heat transfer fluids, reducing reliance on petroleum-oil-based heat transfer fluids and promoting environmental sustainability.

Keywords: Palm kernel oil; bio-oil; heat transfer fluid; binary; sustainability

This study investigates the impact of firing angles on the flow dynamics, temperature distribution, and swirl intensity within an 8 m × 8 m × 30 m tangential-fired furnace with symmetrical cross-sectional geometry. Using Computational Fluid Dynamics (CFD), four firing angles (33°, 37°, 39°, and 41°) were evaluated to identify the optimal configuration for efficient combustion. The results demonstrate that the 39° firing angle provided the most balanced performance, achieving a peak central velocity of 13.24 m/s and a swirl number of 12.75 at selected height to represent critical stages of combustion and flow evolution within the furnace. These conditions promoted uniform temperature distribution and effective fuel-air mixing, minimizing thermal stresses and improving combustion efficiency. In contrast, other angles displayed uneven temperature profiles, lower swirl intensities, and reduced velocity magnitudes, leading to less efficient combustion and increased temperature imbalances. The 39° angle, by optimizing flow and thermal distribution, significantly enhanced combustion stability and reduced the risk of material degradation. The study underscores the importance of firing angle optimization in tangential-fired furnace design, which is crucial for maximizing energy efficiency, minimizing emissions, and extending operational lifespan. Based on these findings, the 39° firing angle is recommended as the optimal configuration for tangential-fired furnaces, offering the best overall performance in terms of combustion efficiency and thermal management.

Keywords: CFD; tangential fired furnace; swirl; temperature; velocity; firing angle

Convergent-divergent (CD) nozzles are critical components in aerospace propulsion systems. The challenges in the CD nozzle design involve minimizing the flow separation and shock wave formation at divergent sections, which can affect the thrust and overall performance. The objective of this study is to investigate the effects of divergence angles on exit velocity, thrust and pressure drop. By utilizing ANSYS Fluent for simulations, the research explores CD nozzles with divergence angles of 7°, 13° and 19° with and without a throat length of 0.3 m. Boundary conditions of inlet pressure, mass flow rate and temperature were constant at 4.41 MPa, 826 kg/s and 3400 K respectively. Grid independence tests are employed to ensure simulation accuracy. The result shows, that higher divergence angles increase exit velocities, Mach numbers, thrust forces and pressure drop. The inclusion of a throat length notably improves these parameters by smoothing flow transition and expanding the air more efficiently at the divergent sections, converting more pressure energy into kinetic energy. The thrust force increases with higher divergence angles with the presence of the throat length as it enhances momentum rates. Model 6 which has a divergence angle of 19°and throat length provides optimal performance for the CD nozzle with a thrust force of 2056.91 kN and pressure drop which is 3959.8 kPa. Using suitable divergence angles and adding a throat length significantly enhances the effectiveness of CD nozzles.

CD nozzles; divergence angles; throat length

The bacterial-algal symbiotic system capitalizes on the intricate relationship between bacteria and algae to effectively eliminate pollutants, presenting a promising solution for widespread application in wastewater treatment. This article examines the evolution and implementation of the bacterial-algal symbiosis system, focusing on its mechanisms of action from three distinct perspectives: mutually beneficial symbiotic relationships, signaling, and gene transfer. Through the prism of rivalry and mutual gain, the mutually beneficial symbiotic connection clarifies the mechanism of action. Group sensing and chemotaxis are two aspects of signal transduction that are essential for maintaining stability of bacterial and algal systems. These processes facilitate the formation of an inter-algal microenvironment while enhancing pollutant removal. Moreover, gene transfer not only contributes to improving the stability of the bacterial-algal symbiotic system but also holds promise for fostering synergistic relationships between bacteria and algae. By promoting up-regulation of gene expression in bio-augmentation bacteria, quorum sensing enhances their colonization rates and improves contaminant degradation within sewage treatment systems. This approach has the significant potential for applications involving gene transfer while demonstrating complex mutualistic interactions. A comprehensive understanding of microalgae-bacteria interactions can optimize both performance and stability within these systems, thereby increasing efficiency in treating environmentally contaminated water sources through advanced treatment technologies.

Microalgal-bacterial system; mutually beneficial symbiosis; quorum sensing; chemotaxis; gene transfer

Turbine blades are an important and critical component in a steam turbine, to convert thermal energy from pressurized steam into mechanical energy to drive a generator shaft to generate electricity. Generally, steam turbine blades are widely made of martensitic stainless steel (MSS) due to the material’s good mechanical properties at temperatures above 500°C. These experimental aims to study low-alloy MSS steel (LAMSS) and highalloy MSS steel (HAMSS) as steam turbine blade materials. Thus, the operation of a 250 MW steam turbine is referred to as a test parameter to evaluate tensile properties, fracture behavior and microstructure at 25°C, 250°C, 400°C and 550°C. In the preparation of LAMSS materials, the composition of C, Cr, Mn, Mo, Ni, V and W elements is different from HAMSS. Next, the quenching process of LAMSS material is performed at 980°C and tempered at 730°C, while HAMSS is performed at 1020°C and tempered at 700°C with oil and air cooling to study the effect of heat treatment on both materials. The tensile test results for LAMSS and HAMSS materials were studied in detail at 550°C, finding that HAMSS has better tensile properties than LAMSS, with a yield strength of 1531.3 MPa, ultimate tensile strength of 1722 MPa, and 16.2% elongation. After the specimen was analyzed, the fracture surface of LAMSS showed a dimple with 33.8% more ductility, and a rough martensite microstructure compared to HAMSS. With this, a study at a temperature of 550°C was carried out to produce the selection of suitable materials to extend the life of the turbine blades, in addition to increasing efficiency and better performance.

Steam turbine; blade materials; tensile properties; fracture behaviour; microstructure

Fermentation broth often contains complex mixtures that make the selective separation and recovery of components challenging. Therefore, recovery of succinic acid from oil palm frond (OPF) fermentation broth model solution by using the liquid-liquid extraction (LLE) method was investigated in this study. Model solutions were prepared by m`ixing succinic acid, glucose, acetic acid, and formic acid in distilled water at various concentration and pH values. Two solvents selected based on suitable solvent characteristics to produce organic phase were used, namely ethyl acetate and diethyl ether. Their effectiveness in extracting succinic acid from the model solution was evaluated. The extraction process involves the formation of two immiscible liquid phase, which are aqueous phase and organic phase. The system was studied with various parameters such as the concentration of the model solution, different type of solvents and the pH of the solution over the LLE process. The concentration values of each tested sample were determined using high-performance liquid chromatography (HPLC). Extraction yield, recovery and distribution coefficient along with solvent efficiency were determined to evaluate the performance of the extraction process. The result demonstrated that diethyl ether showed the highest extraction efficiency and recovery for succinic acid, which were 67.73% and 90.47%, respectively at pH 3 compared to ethyl acetate. In addition, the pH and concentration coefficient of the model solution were found to affect the extraction and recovery of succinic acid for both solvents in maximizing extraction yield. Thus, succinic acid recovery was successfully achieved on the model solution by LLE.

Succinic acid; liquid-liquid extraction; recovery; solvent efficiency; bio-based chemicals

Alcohols is a renewable fuel that might be used in place of fossil fuels. The economical development of each country is greatly impacted by its energy supply. The energy comes from fossil fuels, which are not renewable and have a negative impact on the environment. In this study, waste cooking oil and diesel fuel are compared as a binary combination. Engine testing is conducted with a continuous load at 1450 rpm. This study examined the effects of PF90E10 on engine exhaust valve deposits when ethanol blend fuel was injected during the endurance test in place of base gasoline. Visual examination of the study’s findings revealed that both gasoline samples had some deposit accumulation on their injectors. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis showed that the engine using the PF90E10 produced larger carbon deposits on and around the valve surface. Furthermore, the PF90E10 binary combination may be used in a gasoline engine without any alterations. The SPL increased by 7.8 dB at engine speed in the case of the PF100. Nonetheless, the PF90E10 binary mix’s average SPL was 4.3 dB less than the baseline. Finally, without requiring any engine modifications, binary emulsion may be utilized in engines that use spark ignition. Consequently, E10 may be effectively utilized to lessen negative impacts and decrease reliance on fossil fuels. Furthermore, compared to the baseline, there was a lower concentration of lubrication oil debris cadmium (Cd).

Petrol engine; ethanol; blend fuel; exhaust valve; deposit formation; green alcohol; Lubricating oil

Anion Exchange Membrane Water Electrolysis (AEMWE) technology plays an important role in achieving efficient and sustainable energy conversion. There are many factors contributing to the performance of the AEMWE. This study aims to investigate the effects of parallel flow field design on fluid transport within AEMWE systems. While PEMWE properties are well-documented, comprehensive analysis of AEMWE performance, especially regarding catalysts, flow fields, and bipolar plate fluid dynamics, remains limited. Advancements in these areas are crucial for enhancing electrolyzer efficiency and durability. Through ANSYS Fluent Computational Fluid Dynamics (CFD) simulations, seven flow field models were evaluated, revealing the critical influence of flow field geometry on pressure distribution, hydrogen concentration, and current density. The single-inlet parallel flow field design demonstrated superior pressure uniformity and operational simplicity, with an optimal channel-to-rib ratio of η = 1, improving both efficiency and manufacturability. The results also show that while increasing voltage enhances hydrogen production, it introduces flow turbulence and localized flooding risks, necessitating precise control of operational parameters. The simulation achieved a hydrogen concentration of 35.52 mol/m³ under standard operating conditions, with an improved RMSE of 0.0274, reflecting better accuracy than earlier models. These findings underscore the importance of optimizing both geometric and operational factors to enhance the performance and reliability of AEMWE systems. This research opens the path for efficient energy conversion processes and contributes to the advancement of sustainable energy technologies.

AEMWE; water electrolysis; parallel flow field design; CFD

Natural lighting plays an important role in the design of interior spaces, especially in classrooms where it can improve visual comfort, student performance, and overall well-being. However, one of the main challenges in ensuring adequate natural lighting is glare control. Excessive glare can not only cause visual imbalance, but can also interfere with students’ concentration and performance. Therefore, the assessment of glare in the classroom is a critical aspect that needs to be paid attention to in the design and construction process. This study aims to study the rate of light acceptance to avoid glare which is suitable to be used as a guide to architects and interior designers to design better and more comfortable classrooms for student use. The objective of this study is to identify the appropriate daylighting rate to avoid light glare in the classroom as well as analyze the relationship between the window opening size and orientation with the glare rate in the classroom. This study will focus on Malaysian Public Works Department (JKR) standard designed classrooms, and will use simulation software such as Relux to evaluate the effect of window size and building orientation on glare levels. The results of this study show that East-West oriented classrooms experience glare during peak hours of sunlight with a DGP value of 1.00 to 3.00, affecting visual comfort compared to North-South orientation. Through this approach, this study will provide practical guidance for architects and interior designers in their efforts to contribute to the improvement of design standards in Malaysia, further supporting efforts to improve the quality of education in this country.

Glare; daylighting; classroom; window size; window orientation

The automotive industry faces a critical challenge in integrating sustainable design principles for the survival of future transportation. The use of biocomposite materials in automotive components requires a robust framework to balance sustainability objectives and product performance. The concurrent engineering approach was employed in this work, specifically for the conceptual design generation and selection of biocomposite headrests stay. Ideation processes employing Theory of Inventive Problem Solving (TRIZ) and Bio-inspired Design (BID), together with the best concept selection through Analytic Hierarchy Process (AHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), were executed. TRIZ assisted in problem modelling, as well conversion of specific problems to general problems. Then the contradiction matrix was used to find general solutions. BID facilitated bridging the gap in converting general solutions to specific solutions by providing potential solutions inspired by nature. Consequently, several design concepts were generated, with five alternatives being shortlisted. AHP and TOPSIS were then used in the establishment of criteria global weightages (CGW), performance evaluation for alternatives, ranking, and decision-making process. A2 is the best alternative based on its relative closeness to the ideal solution (C₂ + =0.7808) by demonstrating balanced performance, followed by A4 and A1 with (C₄ +=0.7385) and (C₁ + =0.6619) respectively. Identical framework is applicable to other biocomposite automotive products with similar characteristics, where combining multiple tools in idea generation and selection can serve as a beneficial blueprint for future design processes, particularly within concurrent engineering and sustainable design practices. The future research directions are natural fiber and polymer selection.

Biocomposite headrests; Theory of Inventive Problem Solving (TRIZ); Bio-inspired Design (BID); Analytic Hierarchy Process (AHP); Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS)

The composite of polylactide and flax (PLAF) was compared with steel, through a life cycle assessment (LCA) exercise, in the context of a two-stroke marine engine under-piston door (UPD). The Idemat2024 Excel file was employed to provide the necessary database for the processes involved. Assessment of environmental impacts were evaluated through manual calculations in Microsoft Excel. The functional unit of the study was the UPD of a MAN B&W S60MC engine, measuring at a volume of 3.46x10^-3 m³. Measurement metrics for the evaluation of PLAF and steel were the eco-cost, carbon footprint, cumulative energy demand (CED), human health damage (HHD) and resources. PLAF scored better across four measured values, indicating reduced environmental impact, with the significant drops in resources and eco-cost, by around 81% and 42%, respectively. The CED for PLAF was however higher than steel as a result of rather high values in material compounded by the significance of the processing method, injection moulding. CED for PLAF was 39% higher than steel. Steel impacts were significantly reduced due to its recyclability, by as much as 48% for CED. However, the reductions for PLAF were much less, and only for the end-of-life option of incineration with electricity generation. Overall, from an environmental perspective, PLAF outperforms steel as a potential material for the UPD application.

life cycle assessment, polylactide, flax, bio-composite, two-stroke marine engine

This study presents an innovative methodology that incorporates TRIZ (Theory of Inventive Problem Solving) principles into the Design Thinking (DT) framework to improve idea generation and design development in product engineering. The study uses a conceptual redesign case study of an electric vehicle (EV) strut bar to demonstrate the synergistic potential of combining TRIZ’s structured problem-solving tools with DT’s human-centered approach. The framework aligns TRIZ’s inventive principles, such as curvature modification and engineering contradiction resolution, with DT’s iterative stages, allowing for a seamless transition from user needs to technically optimized solutions. To evaluate and select the most viable conceptual designs, the Analytic Hierarchy Process (AHP) was used, considering key criteria such as material, patent compliance, and cost efficiency. The findings show that using biocomposites instead of traditional materials can result in significant weight savings without sacrificing structural performance, especially when guided by TRIZ-based design strategies. The proposed TRIZ-DT hybrid model not only improves creative ideation, but it also establishes a systematic path for translating abstract concepts into feasible engineering solutions. This integrated methodology provides useful insights into sustainable product innovation, particularly in the context of lightweight automotive structures. The study advocates for broader use of the TRIZ-DT synergy in complex design environments, emphasizing its ability to accelerate innovation in early-stage product development.

TRIZ; design thinking; electric vehicle strut bar; lightweight biocomposites; Analytichal Hierarchy Process (AHP).

Natural fibre reinforced composite applications escalates and become so popular recently, this is due to its ability to be a substitute for synthetic based composites. However, the biological element in its structure such as lignin, wax and hemicellulose become a hindrance to the binding factor between matrix and the reinforcement. Many researchers have found ways to overcome this issue, including using chemical treatments such as alkaline treatment. Thus, this paper presents a study on mechanical, physical and chemical properties on thermoplastics cornstarch composite reinforced by alkaline treated coconut husk fibre. The fabricated samples are varied by the wt.% differences between the 10 wt. % NaOH treated coconut husk fibre and thermoplastics cornstarch using the weight ratio of 70%, 50%, 30% and 10%. The mechanical analysis was obtained by the testing of tensile and hardness following the testing standard of ASTM D368 and ASTM D2240 respectively. Additionally, physical analysis was verified by the testing of moisture content following ASTM D 644, density testing following ASTM D 1895 and scanning electron microscope (SEM). Finally, the chemical analysis was determined from the testing of TGA and XRD. Based on the outcomes, in mechanical properties, both tensile and hardness properties of the alkaline treated samples improved due to the great interfacial binding between the coconut husk fibre and the thermoplastic cornstarch. As for physical properties, the SEM shows the binding quality between the reinforcement and the matrix, the alkaline treated sample shown a good adherence between thermoplastic cornstarch and the alkaline treated coconut husk fibre. Furthermore, moisture content and density analyses of the alkaline treated samples have exposed the data of decreasing and increasing trend respectively due to the elimination of element such as hemicellulose, lignin and wax after the coconut husk fibre undergoes the NaOH treatment. On the other hand, the outcomes of alkaline treated samples for chemical analyses displayed the enhancement of crystallinity and a better thermal property of both XRD and TGA. This occurred due to the elimination of amorphous entities and the modification on coconut husk fibre that changed the chemical properties of the alkaline treated bio composites. Overall, this treatment of NaOH has modified the coconut husk fibre and has enhanced the properties of bio composite of thermoplastic cornstarch reinforced with the alkaline treated coconut husk fibre. This research has discovered the detailed comparison between the sample of alkaline treated sample and the untreated sample in mechanical, physical and chemical properties.

Bio composite; cornstarch; coconut husk fibre; alkaline treatment; thermoplastic

Polyphenylene Sulfide (PPS) is a high-performance thermoplastic widely utilized in aerospace applications due to its exceptional mechanical, thermal, and chemical resistance properties. However, the increasing demand for PPSbased materials has led to significant waste generation, posing sustainability challenges. This review explores the feasibility of PPS recycling for aerospace applications, addressing key knowledge gaps, limitations, and environmental implications. Despite advancements in mechanical and chemical recycling techniques, challenges remain in maintaining the mechanical integrity of recycled PPS, particularly in fiber-reinforced composites. Polymer degradation, chain scission, and contamination affect recycled PPS properties, reducing tensile strength, impact resistance, and crystallinity, which limits its application in load-bearing aerospace components. Furthermore, the lack of standardized testing and certification processes for recycled PPS in aerospace remains a critical gap that hinders widespread adoption. Recycling PPS presents sustainability benefits, particularly in reducing polymer waste, minimizing carbon emissions, and promoting circular economy initiatives. Mechanical recycling offers cost-effective material recovery but results in compromised mechanical performance due to thermal and shear degradation. Chemical recycling, while capable of restoring polymer purity, is hindered by high energy demands and the use of hazardous chemicals. Innovations in reinforcement strategies, such as the integration of glass or carbon fibers, have shown potential in restoring mechanical properties, making recycled PPS suitable for non-structural aerospace applications like aircraft interiors, ventilation systems, and protective enclosures. This review emphasizes the need for further research into optimizing recycling techniques, improving process scalability, and establishing regulatory frameworks to ensure the structural reliability of recycled PPS in aerospace applications.

Recycled PPS; properties; aerospace; sustainability

Mesoporous silica nanoparticle has been garnering a lot of attention as a drug carrier in drug delivery systems due to their unique physiochemical properties, including high surface area, tunable pore structure, high pore volume and their excellent biocompatibility. Despite the advantages, ensuring the drugs are carried to the targeted areas can be a challenge. Hence, a pH-responsive gatekeeper namely chitosan, was used for the surface modification of mesoporous silica nanoparticle. In this study, via the sol-gel method, mesoporous silica nanoparticle was synthesised, and chlorhexidine was loaded into the pores of mesoporous silica nanoparticle. Further coating of mesoporous silica nanoparticle with chitosan conjugated ibuprofen was done to enable the dual drug loading and pH sensitive release. To confirm the loading and the coating on the surface of mesoporous silica nanoparticle, FTIR and TEM was used. The drug release was also studied in-vitro in controlled release behaviour under acidic conditions, mimicking the oral disease environment as well as in neutral conditions as a comparison for when the oral cavity is healthy. At pH 4.5, the maximum release reached 41.0% for CHX and 10.5% for IBP, compared to 30.4% and 7.4% respectively, at neutral pH. The findings suggests that MSN/CHX-CHI/IBP is promising for dual delivery in dental applications, demonstrating pH-responsive behavior with significantly higher release under acidic conditions.

MSN; chitosan; chlorhexidine; ibuprofen; dual drug delivery

This study examines the importance of inclusive design and accessibility of urban public spaces for people with disabilities (PWDs) in areas around Kuala Lumpur. The main focus is to create an inclusive community, in accordance with the concept of ‘City for All’, regardless of social, cultural, economic, or religious status. This is in line with the Sustainable Development Goal 11 (SDG 11) where target 11.7.1., is that urban public open spaces are for the use of all people, regardless of gender, age, and ability. This has identified two main problems, namely, the negative perceptions of accessibility and the design of urban public spaces that does not often meet the needs for the mobility of PwDs and senior citizens. The aim is to establish criterias for universal design in public spaces that are characterized by inclusivity and are easily accessible to all people of the society. The methodology used includes data collection through interviews and direct observation in selected case studies. This process produces not only theoretical basis but also has practical applications in implementing inclusive public spaces in dense urban areas. The result highlights the urgent need for improvements in inclusive planning and the provision of more accessible facilities for all diverse ability. Therefore, improving existing infrastructure to ensure that all individuals can participate inclusively in social life and public space recreation can be realized in major urban public areas in Malaysia.

Inclusive design; accessibility; urban public space; Persons with Disabilities (PwDs)

The growing number of disused heritage buildings in Malaysia presents significant challenges to sustainability, conservation, and sustainable development. Abandoned structures often suffer from structural deterioration and material degradation, posing risks not only to their physical integrity but also to the preservation of historical identity. Conservation strategies such as repair, restoration, and adaptive reuse have emerged as viable solutions, particularly when combined with green technologies and environmentally sustainable practices. These approaches extend the lifespan of buildings while safeguarding cultural heritage. This study investigates sustainability strategies applied in the adaptive reuse of heritage shophouses in Malaysia, with the objective of assessing their suitability for broader application in similar conservation efforts. The research employed a mixed-method approach, beginning with a review of previous literature, followed by field observations and questionnaires distributed to identified respondents. Two heritage shophouses were selected as case studies. The findings highlight that spatial design for natural cross-ventilation, the use of water wells and rainwater harvesting systems, alongside the incorporation of numerous windows and openings, are among the most effective sustainability strategies for adaptive reuse. The study contributes to the discourse on heritage conservation by offering practical insights into integrating sustainable design elements within a contemporary urban context. These findings are expected to support policy development and provide practitioners with strategies to ensure that heritage shophouses remain both functional and relevant within Malaysia’s urban landscape.

Building conservation, adaptive reuse; heritage shophouses; sustainability strategies

Conservation of heritage buildings requires integrated and proactive solutions as a catalyst for structured work. Indeed, if we look back at the past, building elements such as structures and building materials did not receive careful maintenance due to the existence of skilled craftsmen. However, threats such as neglect and rapid modernization have led to deterioration and eroded the value of this heritage. Many buildings do not receive systematic maintenance, leading to severe damage. This study focuses on a framework guide for heritage building conservation with a more comprehensive application and can be applied as a guide for conservation practitioners in the future. The Terengganu Cultural Village was selected as a study sample that included five restored houses and several private own houses. Two research objectives to be achieved through this study are to identify routines during the building conservation and to propose a significant framework as a working model. The qualitative research method was used through semi-structured interviews with skilled craftsmen, museum officials, heritage house owners, and field observations as well as the document analysis. The findings show that there are still a gap between micro and macro approaches in the aspect of routine maintenance of heritage building elements. Therefore, this study highlights the pioneering approach of the Monumentenwacht model as a method for maintaining tangible heritage in the effort to ensure the continuous care of heritage buildings. This study is hoped to contribute to the preservation of heritage buildings through the strengthening of practical frameworks and technical references in the conservation of the nation’s heritage assets.

Conservation; maintenance; preservation; heritage building; framework; Terengganu

Formative assessment is an essential practice that enables us to monitor student progress and provide timely feedback during the teaching and learning process. In engineering education, where conceptual understanding and problem-solving skills are critical, the use of AI-driven applications such as ClassPoint has revolutionized this process. This paper examines the integration of ClassPoint into classroom activities in an Electrical Engineering course, using its key features such as Word Cloud, Short Answer, Slide Drawing, Image Upload and Quiz Areas to engage students actively and gather meaningful feedback. The implementation involved real-time student participation in problem-solving exercises, concept reviews, and interactive discussions. The results indicate that ClassPoint notably enhanced student engagement and understanding. The data collected through its interactive features provided actionable insights, enabling us to identify misconceptions, personalize instruction, and cultivate meaningful learning. In addition, its straightforward integration into teaching workflows promoted collaboration and active participation among engineering students, fostering a deeper understanding of complex concepts. In conclusion, ClassPoint has demonstrated its potential as an effective formative assessment tool, enhancing both the learning experience and the quality of engineering education. Its ability to provide real-time data analysis and support differentiated instruction makes it an invaluable tool for preparing students to excel academically and professionally.

Artificial intelligence; real-time feedback; formative assessment; interactive quizzes; student engagement

Recently, Malaysia has faced significant concerns regarding the low employability and salaries of engineering graduates. The industry is often blamed for the low demand and inadequate compensation for engineers. However, the true extent of these issues among engineering graduates from Malaysian public universities remains unclear. This paper examines the employability of engineering graduates from Malaysian public universities, utilizing data from the national survey of graduate employability (SKPG) conducted by the Ministry of Higher Education (MOHE). The data encompasses engineering graduates from 15 public universities between 2018 and 2021. Quantitative analysis using descriptive statistics was employed to determine the percentage, average, range, and differences in employability outcomes. The results indicate that out of 45,471 engineering graduates over four years, an average of 11,000 students graduated annually. Of these, 66.8% secured employment within six months of graduation, but only 34.6% were hired as engineers. Additionally, 28.6% of graduates had not found employment or pursued further studies within six months. The most common monthly salary range was RM2,000-RM3,000, with 40.8% of employed graduates falling within this bracket. Higher salaries were associated with engineering-related jobs, while the majority of graduates earning less than RM1,500 per month were employed in non-engineering roles. These findings challenge the societal perception that fresh engineering graduates are underpaid relative to their qualifications and workload. The data suggests that low-paying jobs are often unrelated to engineering. Despite the international recognition of Malaysian public university engineering programs by Washington Accord member countries, the employability rate of only 34.6% for engineering roles indicates a need for program improvements. This is particularly concerning given the reported shortage of 30,000 to 60,000 engineers in Malaysia. Further research is required to identify the underlying causes of these employability issues.

Engineering graduates; graduate employability

Engineering identity plays a crucial role in shaping students’ motivation, academic success, and career persistence. This research-in-progress aims to refine and expand the Engineering Identity Development Framework for Malaysia through a pilot Focus Group Discussion (FGD). Building on Alison Godwin’s original framework, which includes Recognition, Interest, and Performance/Competence as core domains, this study investigates additional factors that influence engineering identity in the Malaysian context. The findings suggest the emergence of two new domains: Cultural & Societal Influence and Industry Readiness & Employability. These dimensions reflect the unique socio-cultural landscape and the evolving demands of the engineering profession in Malaysia. The pilot FGD reveals that family expectations and societal pressures play a significant role in shaping students’ engineering identity, while exposure to real-world engineering practices is crucial to ensure industry readiness. This study proposes the integration of these additional dimensions into a more localized framework to better support engineering students in Malaysia. The next phase of the research will involve refining the framework based on expert feedback and conducting further FGDs to validate the findings.

Engineering identity; focus group discussion; Godwin’s framework; cultural & societal influence; industry readiness & employability

After decades of conducting experiments as guided laboratory exercises, Chemical Engineering programs are shifting towards open-ended laboratory experiments. This transition, viewed from the perspective of Engineering Education, is valuable as it enhances student learning, critical thinking, and problem-solving skills. Open-ended experiments better reflect real-world engineering challenges, requiring students to define objectives, design methodologies, analyse data independently, and justify their conclusions. In response to accreditation requirements set by Malaysia’s Engineering Accreditation Council (EAC), the Separation Processes Laboratory I course at Universiti Teknologi Malaysia (UTM) has been redesigned to incorporate predominantly open-ended experiments. This shift aligns with engineering education theories such as experiential learning, constructivism, and problembased learning, reinforcing the development of team working, analytical and decision-making skills essential for professional engineers. This paper presents the rationale behind this transformation, the pedagogical theories that support it, and the implementation process, including modifications to laboratory manuals, assessment rubrics, and instructor roles. Additionally, it discusses the challenges faced by students and instructors, including adjustments to self-directed learning, workload management, and assessment fairness. Strategies to address these challenges and enhance the effectiveness of open-ended experiments are proposed. This work provides valuable insights for institutions considering similar transitions, offering practical guidance on aligning laboratory curricula with accreditation standards and fostering deep learning in engineering students.

Open-ended laboratory experiments; engineering education; experiential learning; separation processes laboratory; chemical engineering curriculum

Conducting systematic literature reviews (SLRs) is an essential but demanding task, particularly for students and early-career researchers coping with complex methodologies and expanding bodies of literature. While artificial intelligence (AI) and large language models provide promising assistance, existing tools remain fragmented, difficult to use, and not tailored to the full SLR process. This study introduces SLRAI Wizards, a ChatGPT-based platform designed to guide researchers through planning, conducting, and reporting SLRs using established frameworks such as PRISMA, PRESS, CASP, and MMAT. The platform offers three engagement modes, self-paced, guided, and hybrid, supported by interactive diagrams, embedded tools, and tutorials. A preliminary evaluation was conducted with 41 participants in a two-hour guided online workshop. Survey data indicated strong positive perceptions: participants rated overall satisfaction at M = 4.33 (SD = 0.94) and reported increased confidence in conducting SLRs using AI tools (M = 4.42, SD = 0.64). The tool’s contribution to understanding the SLR process was highly rated (M = 4.67, SD = 0.62). Thematic analysis of open-ended responses highlighted four areas of impact: structured research guidance, efficiency gains, enhanced research skills, and motivational support. Users valued features such as the Screening Wizard, which allowed rapid abstract processing, but also called for clearer tutorials and a more intuitive interface. These findings suggest that SLRAI Wizards can lower entry barriers to SLRs, making them more accessible, rigorous, and engaging for novices. As a formative study, results establish feasibility and inform design refinements, paving the way for larger comparative evaluations across learning pathways.

ChatGPT; systematic literature review; research skills; research tools; AI-powered

Phenol is one of the hazardous pollutants that contaminates most rivers in Selangor. The concentration of phenol in several rivers in Selangor has exceeded the permissible concentration limits allowed in the Environmental Quality Act 1974. High concentrations of phenol in rivers in Selangor could cause harm to its residents and water creatures. Therefore, this study aims to remove phenol from river water samples in Selangor by extracting phenol using deep eutectic solvent (DES). The extracted phenol was then separated from the water sample using a syringe. The DES solution was produced by mixing DL-menthol and octanoic acid at a molar ratio of 1:3. Five river sites in Selangor were selected as sampling locations, all of which are situated near industrial manufacturing areas. Based on the FTIR results, the developed DES solution contains carbonyl (C=O) bonds, which indicates that the DES is hydrophobic. Additionally, the optimal condition for phenol extraction was achieved using 3 mL of DES solution with a vortexing time of 1 minute. The pH of the mixture was approximately 7. This liquid-liquid extraction method has successfully removed more than 90% of phenol from the water samples. On average, the range of phenol removal from the 5 river sites was between 49.18% - 91.90%. Besides that, the percentage of phenol removal efficiency was highest in the Klang River compared to other rivers, with an average reading of 90.75%, whereas the Bernam River recorded the lowest removal efficiency, with an average of 51.77%.

DES; phenol; liquid-liquid extraction; Selangor’s river; wastewater

Sarawak is the largest producer of sago in the world after Indonesia, with an estimated 32,250 tons of waste produced annually, including sago bark. Sago bark, which consists of cellulose, hemicellulose, and lignin components, can potentially serve as a natural polymer component in the chemical, manufacturing, medicine industry, etc. However, most efforts have focused solely on using cellulose and hemicellulose, while the utilization of lignin has not been fully explored. Furthermore, conventional lignin extraction methods, such as the Kraft process, are widely used in the industry, but they cannot produce pure lignin without impurities. Therefore, this study aims to transform lignin into a new value-added product by extracting it using acidic deep eutectic solvents (ADES). ADES are environmentally friendly solvents that are non-toxic, recyclable, and selective only for lignin. Ten types of ADES were screened to determine the most effective solvent for extracting lignin using COSMO-RS software. The generated activity coefficient values, sigma profile, sigma potential, and excess enthalpy demonstrated that ChClAcetate, ChCl-Formate, and ChCl-Oxalate were the three potential solvents for lignin extraction. The lignin extraction results obtained are consistent with the COSMO-RS findings, where ChCl-Acetate had the highest yield at 82.29%, followed by ChCl-Formate at 73.85% and ChCl-Oxalate at 22.58%. The chemical properties of the extracted lignin display that there were antioxidant sources from phenolic hydroxyl groups in the extracted lignin. Therefore, lignin extraction using ADES is deemed capable of extracting lignin as a value-added product for antioxidant sources, replacing the conventional lignin extraction method, despite reducing the surplus of sago bark.

Biomass conversion; sago palm bark; lignin extraction; acidic deep eutectic solvent; COSMO-RS

As of October 2023, there were 16.77 million registered motorcycles in Malaysia, with 83% of households owning at least one. This positions Malaysia as the fourth highest country in terms of global motorcycle usage. The affordability and flexibility of motorcycles make them a popular mode of transport; however, their high safety risks— due to the lack of protective vehicle body—raise serious concerns. Consequently, understanding the factors contributing to motorcycle accidents is crucial for developing effective safety measures. This study investigates the relationship between road design and weather conditions to understand their impact on motorcycle accident occurrences. A Bayesian Network (BN) approach is employed to examine the causal relationships among various contributing factors, offering a comprehensive understanding of accident dynamics. The study is based on a dataset of motorcycle accidents in Malaysia over the past five years. Findings reveal that road design categories involved in accidents include straight roads (69.2%), curves (12.7%), Y/T-junctions (11.6%), and four-way intersections (5.26%). Weather conditions during accidents were predominantly clear skies (90.54%), followed by rain (8.742%), fog (0.622%), and strong winds (0.096%). The severity of accidents was classified into fatal, serious, minor, and damage. Results indicate that motorcycle accidents are more likely to occur during daytime under clear weather, especially when road hazards such as surface objects are present. The study highlights the importance of well-maintained and clearly divided roads, enforcement against improper vehicle parking, and the use of technology to detect and alert road users to potential hazards.

Motorcycle accidents; road hazard; Bayesian Network; traffic safety; weather conditions

The widespread use of reclaimed asphalt pavement (RAP) can help reduce dependence on raw materials, minimize construction waste, and support sustainable road construction. However, the stiffness of RAP bitumen affects the f lexibility and engineering performance of asphalt mixtures. Therefore, natural rubber modified bitumen (NMB) has been introduced to improve the elasticity and durability of the pavement against traffic loads. This study evaluates the engineering performance and environmental impact of asphalt mixtures produced using RAP and NMB. Five asphalt mixtures with different percentages of RAP (0%, 25%, 50%, 75%, and 100%) were prepared using the Marshall method. Tests involving resistance modulus, moisture susceptibility, mass loss, and boiling water tests were conducted to assess the engineering performance of the produced asphalt mixtures. Meanwhile, the environmental impact will be evaluated based on the leaching tank test and the gas emission test. The results of the engineering performance tests show that adding NMB can balance the stiffness properties of RAP bitumen and restore the elasticity of the asphalt mixture, and this improvement can be observed up to a 50% RAP usage rate. The environmental impact assessment indicates that the release of heavy metals and air pollutants recorded higher readings for the 75% and 100% RAP mixtures. In contrast, the control, 25% and 50% RAP mixtures, recorded nearly identical readings. Overall, the asphalt mixture that combines RAP and NMB has the potential to be implemented to support sustainability agendas in the road engineering industry, where the use of NMB up to a 50% RAP rate can produce a satisfactory asphalt mixture from both engineering and environmental perspectives.

Reclaimed asphalt pavement; natural rubber modified bitumen; engineering performance; environmental impact; sustainable road construction

Starch bioplastics have emerged as environmentally friendly alternatives to petrochemical packaging because they are biodegradable and derived from renewable resources. Nevertheless, the limited functional performance of starch restricts its broader use in packaging applications. This study developed and characterized corn starch films with fig (Ficus carica Linn.) fruit extract at 3, 6, and 9 wt% to evaluate their effects on mechanical properties, biodegradable properties, antioxidant activities, and antibacterial effects for active packaging. The films were analyzed using FTIR spectroscopy, and tested for tensile properties biodegradation rate in soil, antioxidant activity (TPC and DPPH), and antibacterial activity via agar diffusion method. FTIR analysis revealed no new covalent bond formation but indicated molecular interactions between the starch matrix and fig fruit extract. Tensile strength showed an increasing trend with extract concentration, while maximum elongation was achieved at 6 wt%. The 6–9 wt% provided a balanced mechanical profile with small changes in stiffness, suggesting good overall performance stability. Higher extract concentrations led to greater weight loss in soil biodegradation tests, while also increasing TPC values and DPPH radical scavenging activity. However, no antibacterial activity was detected against Escherichia coli, likely due to insufficient levels or limited activation of antimicrobial compounds. Overall, the findings confirm the potential of fig fruit extract as a natural additive capable of reinforcing mechanical strength, enhancing antioxidant capacity, and accelerating the biodegradation of corn starch-based films, thereby supporting the development of sustainable active food packaging that can extend food shelf life. Further research is recommended to assess their effectiveness in real food packaging systems.

Corn starch; Fig (Ficus carica Linn.); active packaging; antioxidant activity; mechanical properties

The uncontrolled disposal of sago bagasse waste from the sago industry has emerged as an environmental concern, potentially contributing to river pollution if not properly managed. With its substantial 705% starch content, there exists potential for its conversion into value-added products, such as animal feed. However, prior to such transformation, a crucial drying process is essential to reduce its high moisture content (93 wt.%), preventing microbial growth and ensuring extended shelf life. This study focuses on evaluating the drying process at temperatures T=60, 70 and 80 °C in fluidized bed dryer (FBD) and micro-oven. Subsequently, the dried sago samples undergo analysis to determine starch, fiber, and ash properties, as well as to study functional organic chemical groups using Fourier infrared transform (FTIR) methodology. Results reveal a significant reduction in sago water content using the FBD compared to oven, attributed to the FBD method’s effective solid particle mixing. Additionally, the FBD achieves a quicker drying rate, requiring only 30 minutes, in contrast to the oven’s 2 hours to reach the desired final moisture content of 11 wt.%. Starch analysis using the FBD indicates an almost 75% higher starch content compared to the oven, reaching approximately 70%. The presence of starch is further validated by the detection of acrylic acid at a wavelength of 1539.72 cm-1 in the FTIR analysis of the FBD sample. In conclusion, sago drying in the FBD at T=80 °C is identified as the optimum drying condition, demonstrating a rapid drying rate to achieve the desired final 11 wt.% moisture content and yielding improved results in both chemical and physical analyses.

Sago bagasse; fluidized bed dryer (FBD); oven drying; starch; chemical properties

The heritage shophouse building is one of the unique architectures in Malaysia and is rich in historical value. Heritage shophouses in Malaysia generally adopt a sustainable approach in their building design, which can help reduce electricity usage and save maintenance costs. However, studies on the sustainability elements of these heritage shophouses have not been widely conducted and are not comprehensive. This study will focus on two main objectives which are to identify the sustainability elements in the design of heritage shophouses in Malaysia and to discuss the suitability of the sustainable approach elements found in heritage shophouses in Malaysia to be applied to contemporary multi-story commercial terrace buildings. This study employs triangulation methodology techniques using three main methods: literature review, observation (case studies), and questionnaires. Heritage shophouses incorporate 16 sustainable design approaches that are suitable for application to modern shophouses today. Meanwhile, the case study reveals 7 sustainable design approaches, such as the use of air wells, water wells, and clay building materials, large openings with louvres, steep roof designs, and flexible interior layouts. This study not only can raise awareness about the value and importance of preserving and conserving these heritage buildings, but also the unique design elements, with their sustainable approaches, have the potential to be applied to contemporary commercial buildings.

Shophouse; heritage; sustainable; design

Public playgrounds are one of the public places where problems of accessibility are often experienced by most Children with Disabilities (CwDs) in Malaysia. Although Universal Design has been implemented in disabled-friendly buildings and inclusive facilities in Malaysia, there are still some constraints in meeting the needs of disabled children. Misinterpretation of the concept of inclusion and no specific guidelines in designing inclusive play equipment, has affected the performance of playing and can bring about the risk of injury among children with disabilities. This study was conducted to determine the level of accessibility and safety of existing inclusive playgrounds used in Malaysia. Two objectives have been highlighted which is to explore accessibility and the design of existing inclusive playgrounds and the diverse design of inclusive safe play equipment. While the second is to determine the need to establish inclusive playground guidelines in public parks and community parks in Malaysia. The selected case studies are Taman Tasik Titiwangsa in Kuala Lumpur, Taman Aman in Petaling Jaya and Inclusive Playground in Bandar Elmina Shah Alam. There are two methodologies for this study, namely [i] bibliographic research through documentations and review of design guidelines documents and [ii] the implementation of access audits at case studies and observation of users. The findings found that the play equipment and the design of inclusive playgrounds follows the minimum standards and are insufficient to meet the needs of CwDs collectively. It can be concluded that there is an effort by the Local Authorities (LAs) in promoting disabled facilities for the local community such as inclusive and safe playgrounds in Malaysia. However, it can still be seen that there is a need for more studies that focus on disabled children in order to be given the opportunity to participate inclusively in the social local community.

Inclusive playground; universal design; accessibility and public playground safety

The global transition towards sustainable energy has intensified the need for alternative power generation technologies, particularly in regions with limited natural resources. Wind energy is a promising option; however, in Malaysia the average wind speed is approximately 2 m/s, which is insufficient for the efficient operation of conventional horizontal-axis wind turbines that generally require at least 4 m/s. This study investigates the potential of Vortex Bladeless Wind Turbines (VBWT), which harness vortex-induced vibrations rather than rotational blades, as a feasible solution for low wind speed environments. Three configurations, namely simple cylindrical, conical cylindrical and complex cylindrical, were evaluated using a comprehensive methodology consisting of a literature review, comparative analysis with a Pugh matrix, and computational fluid dynamics (CFD) simulations. Validation was conducted using real wind and temperature data from Klebang Besar, Melaka, Malaysia. The findings reveal that the simple cylindrical VBWT demonstrates superior aerodynamic stability, a smaller wake-rotation region and lower drag values compared to the other designs. At a wind speed of 1.32 m/s, the simple cylindrical configuration achieved a drag coefficient of 0.37, indicating consistent energy capture efficiency under low wind conditions. In contrast, the conical and complex cylindrical designs exhibited higher turbulence and drag coefficients, limiting their effectiveness. This study concludes that the simple cylindrical VBWT is the most promising design for Malaysia’s wind conditions, with further research recommended on structural durability, optimisation of energy output and economic viability for large-scale deployment.

Renewable energy; wind energy; vortex bladeless wind turbine; low wind speed; Computational Fluids Dynamics (CFD)

Additive manufacturing enables rapid and cost-effective production of prototypes and final products, with Fused Deposition Modeling (FDM) being widely used due to its accessibility and low material costs. This study addresses a key research gap by analyzing the mechanical and thermal properties of 100% recycled ABS printed using an open-source FDM 3D printer. Unlike prior research focusing on blended materials or reinforcement techniques, this study evaluates the standalone performance of recycled ABS, offering insights into its viability for sustainable manufacturing. Recycled ABS filament was produced through mechanical recycling and used to fabricate test samples. Microstructural analysis of fractured samples in X, Y, and Z orientations revealed voids and pores in recycled ABS, while standard ABS exhibited air bubbles in specific orientations. Impact testing per ASTM D256 showed that recycled ABS had an impact strength of 154.67 J/m, significantly lower than the 383.31 J/m of standard ABS. Differential Scanning Calorimetry analysis indicated a glass transition temperature (Tg) of 100.14°C for recycled ABS, compared to 104.97°C for standard ABS, demonstrating relative thermal stability. While 100% recycled ABS exhibits reduced mechanical properties and impact strength, its thermal performance remains stable. This study comprehensively evaluates recycled ABS filament for FDM printing, highlighting its potential for sustainable manufacturing by minimizing material waste. The findings contribute valuable data on the feasibility of upcycling polymer waste for functional 3D-printed products, offering insights into the challenges and opportunities of integrating recycled ABS in green additive manufacturing.

Fused deposition modeling; mechanical properties; thermal properties; recycle acrylonitrile butadiene styrene

The optimization of the extrusion process for biocomposite filaments derived from Polylactic Acid (PLA), reinforced with Wollastonite (WA), and plasticized using Epoxidized Palm Oil (EPO) is crucial for enhancing their performance in Fused Deposition Modeling (FDM) applications in three-dimensional printing. Although PLA is extensively utilized in 3D printing, it frequently exhibits inadequate strength and flexibility for rigorous applications, a limitation that can be mitigated through the incorporation of WA and EPO. This investigation delineates the optimal extrusion parameters that enhance the mechanical properties and consistency of the filaments. The findings indicate that an extrusion temperature of 170°C across both zones, a screw speed of 3 rpm, and a material composition comprising 90 wt.% PLA, 10 wt.% WA, and 3 vol.% EPO yield the highest filament density of 1.32 g/cm³, a tensile strength of 24.03 MPa, and an elongation at break of 1.43%. The screw speed emerged as the most significant variable affecting both filament density and tensile strength, while scanning electron microscopy (SEM) images validated the uniform distribution of WA particles within the PLA matrix, which contributes to the improved mechanical properties. This research substantiates the assertion that process optimization can markedly enhance the mechanical performance and quality of PLA/WA/EPO biocomposites, thereby positioning them as a viable material for high-quality 3D printing applications.

Polylactic Acid (PLA); Wollastonite (WA); Epoxidized Palm Oil (EPO); Filament Extrusion; 3D Printing

Mental health issues among higher education students are drastically increasing. Many researchers have been and are currently working on the problem of mental stress, such as anxiety and depression, among students by using different approaches and machine learning algorithms. Only a few studies focus on the impact of mental stress on psychomotor activity using EEG brainwave signals. The purpose of this paper is to examine the various methods used to detect mental stress, such as self-reported questionnaires, physiological measurements, and electroencephalography for monitoring brain activity during stress. The paper emphasizes the limitations of traditional assessment methodologies, which are subjective and influenced by external factors. It also demonstrated that EEG-based methods, particularly those utilizing power spectrum features like beta and alpha power, are effective in detecting stress. It improves the accuracy and reliability of the stress recognition with the incorporation of machine learning models. In addition, this paper also compared the various machine learning approaches such as SVM, ANN, and KNN for EEG signal classification, as well as identifying challenges in implementation. The purpose of this review paper is to provide insights in the most effective stress detection methods and contribute to the development of a more robust mental health support system for students.

Mental health; EEG; brainwave signal; classification

Deep Vein Thrombosis (DVT) has garnered significant attention from various stakeholders due to its simplistic yet fatal nature. This study focuses on investigating blood flow in the deep veins, particularly at the lower calf leg muscle using Photoplethysmography (PPG) techniques. The primary objective is to analyse the pattern changes in deep vein blood flow under different simulated DVT conditions, including no DVT, slight DVT, medium DVT, and severe DVT. The PPG sensor was utilized to measure changes in deep vein blood volume by attaching it to tibialis posterior (TP) area at lower limb. Data collection procedure implemented was adapted from multiple studies on the non-invasive assessment of Deep Vein. A healthy PPG waveform was measured by having the lower muscle calf contracting and relaxing for 70 seconds, thus obtaining the mean value IR reflectance at 79277. This data was benchmarked with the simulated DVT conditions by applying pressure of 50 mmHg, 100 mmHg and 150 mmHg on upper leg muscle calf, obtaining mean value reflectance of 76179, 75253 and 75092 respectively. Based on the results, the PPG waveform clearly illustrated that blood flow in the vein was significantly reduced under simulated severe DVT conditions. Furthermore, noticeable differences in the PPG waveform were observed between each simulated DVT condition. These findings strongly indicate a possible thrombosis that restricts oxygenated blood flow from deep veins to the heart.

Deep vein thrombosis; non-invasive detection; reflectance photoplethysmography

The present study investigates the influence of plate stiffeners on the ultimate moment capacity of rectangular concrete-filled double-skin tubular (CFDST) beams subjected to pure bending loads. This research assesses the flexural performance of CFST, CFDST, and plate-stiffened CFDST beams by comparing their moment-bearing capacities and failure modes. The experimental program included six specimens, comprising one CFST beam, one CFDST, beam, and four CFDST beams strengthened with plate stiffeners. The stiffeners were welded to the inner face of the outer tube that carried out through pre-drilled holes, positioned at spacing intervals of 20t and 40t, with t indicating the external tube thickness. The experimental findings demonstrated that incorporating internal steel tubes improved the ultimate flexural of CFDST beams by approximately 4.24 % relative to CFST beams. The addition of plate stiffeners to the CFDST beams exhibited a marked enhancement in ultimate moment capacity, ranging between 7.1% and 22% over the unstiffened CFDST specimen. This improvement was more pronounced as closer intermittent weld spacings were adopted for the plate stiffeners. This study proposes a design model for predicting the peak flexural capacity of plate-stiffened CFDST beams. Furthermore, it provides detailed insights into their ultimate moment capacity under the influence of intermittently welded plate stiffeners. A design model incorporating confinement effects from intermittent stiffeners predicts ultimate capacity with an average accuracy of 96%.

Concrete-filled double-skin tubular beam; plate stiffener; intermittent welding spacing; flexural loading; deformation.

The growing accumulation of non-metallic printed circuit board (NMPCB) waste poses significant environmental challenges, motivating its reuse as a functional filler in polymer composites. This study investigates the effect of palmitic acid (PA) surface modification on the thermal, mechanical, morphological, and water absorption properties of epoxy/ NMPCB composites. NMPCB powders were treated with varying concentrations of PA (0.1–1.0 M) and incorporated at 10 wt% into an epoxy matrix. Fourier-transform infrared spectroscopy confirmed that PA modification reduced the hydroxyl group content on NMPCB surfaces, enhancing hydrophobicity and filler–matrix compatibility. Thermogravimetric analysis revealed improved thermal stability and increased char residue with higher PA concentrations. Mechanical testing demonstrated that PA modification significantly enhanced tensile strength up to 49.1% and impact strength up to 43.9% compared to unmodified composites, while flexural strength was improved by addition of 10 wt% untreated NMPCB but decreased significantly upon higher PA concentration modification due to altered stress transfer. Scanning electron microscopy confirmed improved interfacial adhesion and reduced void formation with PA treatment. Furthermore, water absorption was markedly reduced in epoxy/NMPCB-PA composites, with up to 99.5% decrease at 1.0 M PA, indicating superior moisture resistance. These results demonstrate that modifying NMPCB with palmitic acid effectively improves the strength, durability, and water resistance of epoxy composites, offering a practical and sustainable way to reuse electronic waste.

Recycling; non-metallic printed circuit board; palmitic acid; mechanical strength, water absorption

The escalating levels of atmospheric CO₂ and the urgent need for sustainable energy solutions have driven interest in carbon capture and utilization (CCU) technologies. This study investigates the production of methanol (CH₃OH) through the thermocatalytic hydrogenation of CO₂ , offering a dual solution to mitigate greenhouse gas emissions and produce a valuable chemical feedstock. The research encompasses three primary objectives: designing a complete methanol production process, simulating the process using Aspen Plus® software, and conducting an economic analysis to evaluate viability. A conceptual process was developed, integrating alkaline water electrolysis (AWE) for hydrogen production, a fixed-bed reactor for CO2 hydrogenation using a Cu/ZnO/Al₂O₃ catalyst and separation units for methanol purification. The process achieved a methanol yield of 355.3 mmol/g–¹ with 99.85% purity under optimized conditions (75 bar, 284°C). Simulation results validated the design, highlighting energy-saving opportunities such as heat recovery from exothermic reactions. Economic analysis revealed a total capital investment (CAPEX) of MYR 243.60 million and an annual operational cost (OPEX) of MYR 271.00 million. The project demonstrated strong profitability, with a 22% return on investment (ROI) and a payback period of 4.54 years. The net present value (NPV) of MYR 213.16 million confirmed long-term financial viability. This study concludes that thermocatalytic hydrogenation of CO₂ to methanol is technically feasible, economically viable, and environmentally sustainable.

Thermocatalytic CO₂ ; methanol; Aspen Plus® modelling; techo-economic analysis; Carbon Capture and Utilization (CCU)

Microplastics (MP) have emerged as persistent pollutants in aquatic environments, often coexisting with other contaminants in domestic wastewater. Conventional coagulants such as alum are effective but present environmental drawbacks, including harmful sludge generation. This study investigates soybean pulp extract (SPE), a plant-based and protein-rich byproduct of soymilk production, as a natural coagulant for MP removal from municipal wastewater. SPE was prepared using ethanol extraction with and without sodium chloride (NaCl) supplementation, and its protein content, zeta potential, and coagulation performance were evaluated. Jar tests were conducted with varying SPE and alum dosages (10–50 mg/L) in wastewater spiked with 500 mg/L polyethylene (PE) microplastics. The concentration of microplastics used was higher than that normally found in domestic wastewater, and exposure to this concentration was lethal to microorganisms. Results showed that ethanol extraction alone was sufficient for protein recovery, while NaCl addition offered no significant advantage and introduced further negative charge to the extract. The optimum SPE dosage was identified at 30 mg/L, achieving 557.67± 50 mg/L of floc sediments, comparable to alum at the same dosage. FTIR confirmed the removal of PE microplastics, with peaks observed at 2915–2917 cm–¹. SPE achieved up to 96.22% turbidity removal and 59.58% total suspended solids (TSS) removal, which is nearly comparable to alum, although alum was more effective at lower dosages. These findings demonstrate the potential of SPE as an eco-friendly alternative coagulant, capable of microplastic and pollutant removal under real wastewater conditions.

Coagulation; wastewater; microplastic, soybean pulp; zeta potential