William W F Chong

University of Technology Malaysia | UTM · School of Mechanical Engineering

Waste activated sludge (WAS) derived from food manufacturing poses critical environmental threats, necessitating sustainable management strategies. To address the challenges associated with the high moisture and ash contents of WAS, co-pyrolysis that incorporates polyethylene terephthalate (PET) offers a potential solution to transform WAS into val...

Accurate determination of mode III interlaminar fracture toughness is paramount in composite materials due to its critical role in edge delamination, which nonetheless remains a significant challenge encountered. As such, this study focused on the investigation of mode II and III interlaminar fracture behavior of carbon fiber (CF)/epoxy composite l...

Reducing friction energy losses is crucial in mechanical systems, often achieved through lubrication strategies employing friction modifiers. These additives adsorb onto surfaces, forming boundary film to prevent solid–solid contacts. However, atomistic simulation techniques used to study these additives often ignore surface roughness due to high c...

This study addresses the challenge of enhancing lubrication performance by exploring the potential of a protic ionic liquid (IL), [Oley][Oleic], in conjunction with carbon nanotube (CNT) mixtures. The primary objective is to determine the optimal CNT concentration that achieves effective lubrication for the IL-based lubricant. Through experimental...

The present study investigates the impact of integrating selective exhaust gas recirculation (SEGR) with a combined cycle gas turbine system (CCGT) and post-combustion capture (PCC) in a model power plant. The impacts of ambient temperature, turbine inlet temperature (TIT), and pressure ratio (PR) on the overall thermal and exergetic efficiencies a...

The inconsistent conductivity and surface roughness of commercially available chemical vapour deposition (CVD) monolayer graphene films have limited their widespread adoption in optoelectronic devices. This study presents a novel approach to address this issue by investigating the effect of post-thermal annealing on the sheet resistance (Rs) and su...

Wood-based panels provide efficient alternatives to materials such as plastics derived from traditional petroleum sources and thereby help to mitigate greenhouse gas emissions. Unfortunately, using indoor manufactured panel products also results in significant emissions of volatile organic compounds including olefins, aromatic and ester compounds,...

Due to environmental concerns, natural fibres are getting their importance as reinforcement in polymer composites. Nevertheless, their hydrophilic nature makes natural fibre composites susceptible to moisture attack. In this regard, one possible solution is to utilise hybrid synthetic/natural fibre composites. This paper aims to characterise the mo...

Fast growing Kariba weed causes major problems and pollution on freshwater and shellfish aquaculture systems by interfering with nutrient uptake of crops, restricting sunlight penetration, and decreasing water quality due to massive biomass of Kariba weed remnants. Solvothermal liquefaction is considered an emerging thermochemical technique to conv...

The valorization of chicken manure via pyrolysis can give biowaste a second life to generate value and contribute to the circular economy. In the present study, the thermal degradation and pyrolysis characteristics of chicken manure pyrolysis were investigated via thermogravimetric analyses (TGA) coupled with optimization methods. Thermogravimetric...

Nanocomposites play critical roles in catalytic oxidation, wastewater treatment, and other chemical engineering fields. Therefore, the strategies to develop multifunctional nanocomposite systems through chemical synthesis, physical doping, and assembly have been explored. The existing challenges including fussy preparation processes and conditions...

PEDOT:PSS is a conducting organic polymer widely studied for a transparent conductive electrode. The conventional method to fabricate PEDOT:PSS thin film involves a post-treatment process entailing dipping into strong and toxic saturated acid to enhance the film’s conductivity. Eliminating the post-treatment process reduces excess strong saturated...

Substrate toxicity would limit the upgrading of waste biomass to medium-chain fatty acids (MCFAs). In this work, two fermentation modes of electro-fermentation (EF) and traditional fermentation (TF) with different concentration of liquor fermentation waste (20%, 40%, 60%) were used for MCFAs production as well as mechanism investigation. The highes...

Vegetable-oil-based biolubricants are an excellent alternative to conventional lubricants. Instead of focusing on novel feedstocks, these biolubricants should be further elucidated based on their fatty acid composition, which influences their tribological properties. Therefore, the study utilises gene expression programming (GEP) to derive a bounda...

The valorization and conversion of biomass into various value-added products and bioenergy play an important role in the realization of sustainable circular bioeconomy and net zero carbon emission goals. To that end, microwave technology has been perceived as a promising solution to process and manage oil palm waste due to its unique and efficient...

Traditional disposal of animal manures and lignocellulosic biomass is restricted by its inefficiency and sluggishness. To advance the carbon management and greenhouse gas mitigation, this review scrutinizes the effect of pyrolysis in promoting the sustainable biomass and manure disposal as well as stimulating the biochar industry development. This...

Prolonged exposure of fiber reinforced composite structures to high moisture and temperature in outdoor environment could lead to the degradation of mechanical properties of the materials. To provides reliable prediction of the delamination behavior as the moisture progressively ingresses into the composites, we proposed a Bilinear‐Exponential Trac...

Approximately 17.9% of fuel energy is used to overcome engine friction in passenger cars with engine frictional losses further broken down into losses along hydrodynamic (40%), elastohydrodynamic – due to pure sliding motion (40%), mixed (10%) and boundary (10%) lubrication regimes. Therefore, to assess the tribological influence of TMP trioleate a...

We analyzed the problematic textile fiber waste as potential precursor material to produce multilayer cotton fiber biocomposite. The properties of the products were better than the current dry bearing type particleboards and ordinary dry medium-density fiberboard in terms of the static bending strength (67.86 MPa), internal bonding strength (1.52 M...

The alarming output of waste activated sludge (WAS) from industries requires proper management routes to minimize its impact on the environment during disposal. Pyrolysis is a feasible way of processing and valorizing WAS into higher-value products of alternate use. Despite extensive research into the potential of WAS through pyrolysis, the technol...

Pyrolysis is a green and effective method for converting various waste streams into products with bio-energy potential. Waste activated sludge (WAS) from industries requires post-treatment before disposal and will cause serious pollution if not managed properly. Pyrolysis is a viable method for converting WAS into higher-value bio-products. This is...

Pyrolysis is a thermo-chemical decomposition process that converts organic or inorganic materials into solid, liquid and gaseous products. The pyrolysis process involves multiple complex chemical reactions, and the derived products are highly dependent on the pyrolysis operating parameters and type of feedstock. In the present review, progress on t...

Vegetable oil–based bio-lubricants possess potential as an alternative to mineral oil–based lubricants due to their biodegradability and renewability. However, a detailed examination of the publication focus, trend, and future direction related to these bio-lubricants’ tribological and physicochemical properties is scarce. Therefore, the study pres...

A biophotovoltaic (BPV) system is a developing renewable energy technology that promises carbon-free electricity generation from solar energy, by utilizing photosynthetic exoelectrogenic microorganisms. The electrical power production of BPV devices, on the other hand, is relatively low, and this has become a significant challenge for this new tech...

A biophotovoltaic (BPV) system is an emerging photo-bio-electrochemical technology that promises bioelectricity generation through the photosynthesis of exoelectrogenic microorganisms. An algal pool or floating photobioreactor with algae cultivation medium is a potential electron source for sustainable operation of such BPV device. Therefore, bioel...

Microwave-induced in-situ catalytic co-pyrolysis of empty fruit bunch (EFB) with truck tire (TT) using a low-cost heterogeneous catalyst to produce aromatic-rich pyrolytic oil is proposed. In this study, the effect of catalyst type and catalyst-to-feedstock ratio were investigated. Three types of catalysts were used, namely activated carbon (AC), c...

The worldwide decarbonisation movement has turned ammonia into one of the attractive alternative fuel for power generation. This paper reviews the progress of ammonia combustion technologies in spark ignition engine, compression ignition engine, and gas turbine. Relevant publications from prominent academic journals were acquired from credible scho...

Rising environmental concern on industrial waste disposal drives the exploration of alternative managing methods. The route of waste-to-energy sparks interest as the uncontrollable amount of waste can be potentially transformed into energy-rich by-products. Waste activated sludge (WAS) from the food-manufacturing industry is a novel feedstock in py...

In the present study, oil palm empty fruit bunch (EFB) was subjected to microwave-induced fast pyrolysis. It has been demonstrated that EFB pyrolysis with activated carbon (AC) as microwave susceptor significantly increases the bio-oil yield (38.26 wt%) at an optimised temperature of 500 °C as compared to the EFB pyrolysis without AC (1.89 wt%). Th...

In biodiesel-fueled compression-ignition (CI) engines, dilution by unburned biodiesel has been found to have adverse effects on the boundary lubrication properties of additives in fully formulated engine lubricants. Such dilution of engine lubricants could be even more pronounced for CI engines running on higher blend concentrations of biodiesel. G...

The increasing amount of waste generated globally due to industrialisation and economic activities require a proper and efficient waste management route. Turning waste to energy via pyrolysis pathway is a promising solution to reduce the amount of waste while generating useful end products. In the present study, microwave pyrolysis of horse manure...

Biomass-based feedstock is an attractive alternative to fossil fuel due to its sustainability and potential as a clean energy source. The present work focuses on the valorisation of horse manure biowaste to produce bioenergy via microwave-assisted pyrolysis technique. The thermal decomposition process is conducted by considering the effects of pyro...

Fatty acid methyl ester (FAME) possesses good lubricity properties, prompting numerous research work to explore their potential as lubricant additives. However, fully formulated lubricants consist of additive packages, which includes essential anti-wear agents, such as zinc dialkyldithiophosphate (ZDDP). Adding FAME into a lubricant could lead to a...

The study simulates the lubricant Stribeck curve for Palm Methyl Ester (PME) by coupling modified Reynolds solution with Greenwood and Tripp’s rough surface contact model. The predicted lubricant Stribeck curves for PME is validated with measured data from a pin-on-disc tribometer. The Reynolds equation is modified to accommodate for the lubricant...

Combustion characteristics of palm biodiesel/methyl esters (PME) and natural gas (NG) blend were examined using a model gas turbine swirl burner at vane angle (θ) 30°, 45°and 60°. A twin fluid air blast atomiser was utilised for atomising liquid fuel at air-to-liquid ratio (ALR) 2.50. Swirling flow was initiated by using an axial swirler as main ai...

The effect of microwave susceptor design on the heating profiles of co-pyrolysis between waste truck tyre and empty fruit bunch was studied. Carbonaceous susceptor was used to elevate the pyrolysis temperature along with increased heating rate. Different design of microwave susceptor and its effect towards the heating profiles of the studied co-pyr...

Transforming waste to energy is essential in view of the need to search for greener and more sustainable energy sources. Such transformation of energy is also aligned with the aim of reducing excessive waste generation whilst creating potential biofuel pathways for power generation. In the present study, animal waste in the form of horse manure is...

Algae is a potential third-generation biofuel sources that can be used to produce high quality liquid fuel. The physio-chemical properties of algae depend on the species type, of which can also vary with climate, geography and environmental conditions. In this study, the pyrolysis behaviour of a brown macroalgae, Sargassum polycystum (SP), obtained...

The characteristics of pool fire burning of methyl esters/biodiesels of palm, soybean, coconut and their blends with diesel were compared against baseline diesel. Pool fires were established and investigated using four different crucible sizes, ranging between 40 mm and 70 mm in diameter to obtain the mass burning rate, flame height and emissions o...

Trimethylolpropane (TMP) esters possess good frictional properties, portraying good potential as alternative bio-lubricants. However, the most common TMP ester, which is TMP oleate, is found to be widely used only for hydraulics application. Therefore, to explore its potential usage in automotive applications, the present study determines the frict...

Fundamental understanding of piston ring-pack lubrication is essential in reducing engine friction. This is because a substantial portion of engine frictional losses come from piston-ring assembly. Hence, this study investigates the tribological impact of different piston ring profiles towards engine in-cylinder friction. Mathematical models are de...

Accurately predicting frictional performance of lubrication systems requires mathematical predictive tools with reliable lubricant shear-related input parameters, which might not be easily accessible. Therefore, the study proposes a semi-empirical framework to predict accurately the friction performance of lubricant systems operating across a wide...

Experimental and numerical investigations were performed to study the combustion characteristics of synthesis gas (syngas) under premixed swirling flame mode. Four different type of syngases, ranging from low to high H2 content were tested and simulated. The global flame structures and post emission results were obtained from experimental work, pro...

The spray combustion characteristics of sunflower (Helianthus annuus) biodiesel/methyl esters (SFME) and 50% SFME/diesel blend and diesel were investigated via a liquid swirl flame burner. The swirl flame was established at atmospheric condition by using a combined twin-fluid atomiser-swirler configuration at varied atomising air-to-liquid ratios (...

It is essential that moisture attack be considered when characterising interlaminar fracture toughness. However, limited work has been reported on the correlation between interlaminar fracture toughness of mixed mode I/II ratios and moisture content. Therefore, the present study aims to characterise the delamination of carbon/epoxy composites, imme...

Horse manure contains potential source of bioenergy that can be pyrolysed to obtain bio-oil and synthesis gas. In the present work, horse manure samples collected from the horse stable in Universiti Teknologi Malaysia were analysed through thermogravimetric analysis (TGA) to determine the Arrhenius parameters and thermodynamics properties. TGA was...

The increasing demand for clean and sustainable energy sources provides the impetus for the development of alternative fuels. Recent development of fuel-flexible gas turbine technologies enables the use of alternative non-fossil fuels that could play key roles in contributing to the global efforts in meeting emissions targets. This review highlight...

Arising world economy issues, such as depletion of world crude oil reserves, are having an impact on the transportation field and automotive manufacturers. Burning of petro-diesel contributes to the increase in greenhouse gas emissions, which traps heat within the atmosphere. To prevent this, an approach was proposed through alternative fuel produc...

The paper simulates lubricant Stribeck curve for SAE grade engine lubricants by coupling Reynolds solution with Greenwood and Tripp's rough surface contact model. The predicted lubricant Stribeck curves for SAE5W40 and SAE15W40 engine lubricants are validated with measured data from a pin-on-disc tribometer. The proposed mathematical solution is sh...

Using Molecular Dynamics (MD) simulation, the current study determined the surface forces between iron oxide surfaces when immersed in methyl oleate. Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies (COMPASS) force field was used to model the methyl oleate molecules. For the nano-confinement simulation, the iron oxide...

Piston top compression ring Engine cylinder liner Friction force Lubricant film thickness Reynolds equation A better fuel-efficient automotive engine is more sought-after to promote greener environment in the era of global warming. One of the factors to cause the increase of fuel consumption in vehicles is the frictional loss within an internal com...

To isolate shearing of boundary film from direct surface-to-surface asperity interactions, the study determines boundary lubrication properties of palm oil-based TMPE (PTMPE) using Lateral Force Microscopy coupled with fluid imaging. PTMPE is produced through a series of 3-step transesterification processes, converting palm oil (PO) into palm methy...

A high-performance microscopic observation system was developed and integrated with a purpose-built pin-on-disk type tribotester. This allows for simultaneous in situ measurements of the vertical displacement and friction force of a pin sliding on disks lubricated with nanometer-thick liquid films at velocities up to 0.1 m/s, with accuracies of app...

The switch from petro-diesel fuel to biodiesel blends for Compression Ignition engines have raised tribological performance concerns among major automobile manufacturers. Biodiesel fuel dilution on engine lubricants could have adverse long-term effects on the engine efficiency, which will reduce the fuel economy, thus, leading to higher greenhouse...

Energy demand in the transportation sector across Southeast Asian (SEA) region is rapidly increasing. This poses a challenge to the sector in mitigating greenhouse gas (GHG) emissions because of its heavy reliance on fossil fuels. Decarbonisation efforts tend to focus on the use of low carbon energy, often neglecting frictional losses in vehicles....

Synthesis of carbon nanotubes (CNTs) was performed by using a laminar premixed flame burner at open atmospheric condition. The growth of CNTs on the substrate was supported catalytically by a transition metal under high temperature, hydrocarbon-rich environment. Analysis of the CNTs using high resolution electron microscope reveals the structure of...

The switch from petro-diesel fuel to biodiesel blends for Compression Ignition engines have raised tribological performance concerns among major automobile manufacturers. Biodiesel dilution on engine lubricants could have adverse long-term effects on the engine efficiency, which will reduce the fuel economy, thus, leading to higher greenhouse gas e...

To explore its potential as a biolubricant/additive, the study determines the frictional properties at various lubrication regimes for biodiesels derived from vegetable oils, hydrogenated vegetable oil and animal fat. It is found that the frictional characteristics for the biodiesels can be divided into Group I (feedstocks from winter crops) and Gr...

This paper presents a mathematical model of sliding, adhering contact between a rigid parabolic indenter and a multi-layered elastic solid, which is assumed to comprise of a homogeneous coating bonded through a functionally-graded transitional layer to a homogeneous substrate. The adhesive forces in this investigation are modelled using Lennard-Jon...

Biodiesel lubricity is generally characterised through the wear scar diameter produced using high frequency reciprocating rig (HFRR). More recently, the adequacy of Stribeck curve in characterising biodiesel lubricity is also being investigated. However, for a rough surface contact, asperity interactions at nano-scale are predominantly the root cau...

The present study focuses on the characterization of carbon nanotubes (CNTs) synthesized from flame under an atmospheric condition. A laminar flame burner was utilized to establish a rich premixed propane/air flame at the equivalence ratio Φ = 1.8-2.2. The flame was impinged on a stainless steel wire mesh coated with nickel (Ni) catalyst to grow CN...

Solid and elastic contact problems have been thoroughly investigated before. The most recent efforts incorporate the use of the Lennard-Jones (LJ) potential to describe the inter-surface forces that are present and substantial in micro-sized contact problems. But little work has been done on viscoelastic contact problems. Hence, there is a need to...

At diminishing separations, the load carrying capacity of opposing rough surfaces is distributed among asperities across a smaller contact area as compared with the apparent contact area. An improved understanding on asperity interactions is therefore required in order to better predict the tribological behaviour of a rough surface contact. In this...