Malaysian Journal of Microscopy

SYNTHESIS OF SAGO-BARK BASED ACTIVATED CARBON VIA MICROWAVE ACTIVATION FOR AMOXICILLIN REMOVAL: OPTIMIZATION VIA RESPONSE SURFACE METHODOLOGY

2025-12-04T09:57:09+00:00

Antibiotics such as amoxicillin (AMOX), when introduced into water bodies due to inadequate wastewater treatment, can pose serious environmental risks, affecting aquatic life. This concern led to the present study aimed at synthesizing sago bark-based activated carbon (SBAC) for the adsorption of AMOX from water. SBAC was prepared using a combined physicochemical activation process, which involved chemical activation with potassium hydroxide (KOH) and subsequent microwave-assisted physical activation using carbon dioxide (CO₂) gas. The optimization of SBAC synthesis was realized harnessing response surface methodology (RSM) with a central composite design (CCD). The optimal conditions identified were 556.41 watts for radiation power, 6.06 minutes for activation time, and a KOH impregnation ratio (IR) of 1.76 g/g. Under these conditions, AMOX uptake and SBAC yield were optimized at 75.65 mg/g and 31.54 %, respectively. The models accurately predicted actual values of 77.59 mg/g for AMOX uptake and 32.56 % for SBAC yield, with low errors of 2.50 % and 3.13 %, confirming the models' reliability. The uptake of AMOX was primarily swayed by radiation power, followed by IR, while the yield of SBAC was mostly governed by radiation power, succeeded by activation time. Scanning electron microscopy (SEM) analysis revealed that the raw sago bark had a non-porous structure, whereas the activation process created a highly porous SBAC surface, demonstrating the effectiveness of the activation methods. Isotherm analysis indicated that AMOX adsorption onto SBAC followed the Freundlich model, achieved an adsorption capacity (Q_m) of 110.52 mg/g, suggesting multilayer adsorption on a heterogeneous surface. Overall, the findings highlight that SBAC is an efficient, low-cost, and sustainable adsorbent for mitigating antibiotic pollution in aquatic environments.

NOVEL SYNTHESIS OF GRAPHENE OXIDE (GO) FROM PYROLYZED WASTE TIRE: TUNING THE OXIDATION DEGREE VIA VARYING KMnO4

2025-12-09T06:26:13+00:00

Graphene oxide (GO) is highly valued for its tunable properties, making them versatile for high-performance applications. Reliance on high-purity graphite flakes as the primary precursor increases production cost and raises environmental concerns, highlighting the need for sustainable alternatives. Converting carbon from waste materials into GO offers a green approach, but remains challenging due to their heterogenous composition and lower graphitic order compared to conventional graphite. Thus, this research presents the synthesis and characterization of GO from recovered carbon black (rCB) of pyrolysis waste tires through modified Hummers’ method, with a focus on tuning the concentration of oxidizing agent (KMnO₄). The synthesized materials were thoroughly analyzed using X-ray diffraction (XRD), Fourier-transformed infrared spectroscopy (FTIR), and field emission scanning electron microscope-energy dispersive X-ray (FESEM-EDX). Results show that increasing KMnO₄ concentration promoted the oxidation and exfoliation of rCB to GO, as shown by the XRD peak shifting to a lower angle (2θ = 11.23°), which was first observed at a KMnO₄ concentration of 3 g. FTIR analysis revealed that increasing KMnO₄ concentration enhanced the oxidation of rCB, as supported by the increase in the absorption bands at 3395 cm^-1 (O-H), 1735 cm^-1 (C=O), and 1215 cm^-1 (C-O) in GO-5 samples, indicating successful incorporation of oxygen-containing functionalities with higher oxidation levels. FESEM images further supported these findings, showing a morphological transformation from aggregated spherical particles in raw rCB to thin, wrinkled GO sheets at higher KMnO₄ concentrations, indicating successful exfoliation and GO formation. These findings demonstrate that controlling the concentration of KMnO₄ influences the oxidation degree and structural properties of synthesized GO from carbon source derived from waste and provides a promising pathway for recycling waste into high-value materials.

TOOL WEAR ANALYSIS OF 22MNB5 BORON STEEL CUTTING TOOLS IN ALUMINIUM ALLOY MACHINING UNDER LUBRICATED AND UNLUBRICATED CONDITIONS

2025-12-04T09:57:10+00:00

This study explores the potential of 22MnB5 boron steel as a cutting tool material for machining AA6061 aluminium alloy under lubricated and unlubricated conditions. Conventional high-speed steel (HSS) tools often face rapid wear and limited hot hardness at high cutting speeds, while carbides and ceramics, though effective, are costly or brittle. To address this gap, four 22MnB5 samples with different hardness levels (45.5–70 HRC) were prepared through hot stamping and heat treatment. Hardness tests, ball-on-disc wear experiments, and machining trials were conducted at cutting speeds ranging from 100 to 450 m/min with a constant feed of 0.1 mm/rev and depth of cut of 0.5 mm. The heat-treated sample (70 HRC) showed the best tribological performance, achieving the lowest coefficient of friction (0.2114) and superior wear resistance. Machining trials revealed that lubrication reduced tool wear by an average of 15.8 %, while the most stable performance occurred at cutting speeds of 200-350 m/min. Wear mechanisms varied with speed and condition, shifting from built-up edge formation at lower speeds to tribolayer effects at higher speeds. Overall, the findings suggest that 22MnB5 boron steel, particularly in its heat-treated form, provides a durable and cost-effective alternative to HSS, with promising potential for sustainable machining applications.

MICROSTRUCTURE AND SURFACE QUALITY ANALYSIS OF 17-4PH STAINLESS STEEL FILAMENT FABRICATED VIA VACUUM-ASSISTED FUSED DEPOSITION MODELING: PRE-DEBINDING & PRE-SINTERING

2025-12-09T06:27:20+00:00

In recent years, both polymer-based materials and stainless steel have been widely used in additive manufacturing, especially in the automotive and medical sectors. Among these materials, 17-4PH stainless steel filament, a polymer-based composite, has gained attention for aerospace and marine applications due to its excellent strength, corrosion resistance, and mechanical properties. However, with the growing use of fused deposition modeling (FDM) for metal fabrication, a deeper understanding of how the filament microstructure influences the final properties of printed components is needed. While previous research has emphasized microstructural integrity for successful debinding and sintering, limited attention has been given to the pre-processing stages. This study investigates the surface roughness of 17-4PH stainless steel filament fabricated via vacuum-assisted FDM before the debinding and sintering process. Samples measuring 10 mm x 10 mm x 5 mm were produced using an Ultimaker S5 at various vacuum pressures, layer heights, and printing speeds. Surface roughness was evaluated using a surface roughness tester, and surface morphology was analyzed using scanning electron microscopy (SEM). Each analysis shows that the sample printed using a vacuum has reduced surface roughness up to nearly 8.5 %. This improvement is attributed to vacuum-assisted printing, which reduces contamination, minimizing oxidation and porosity during the printing process. Besides that, outgassing characteristics and vacuum stability can also influence the printing. The printing parameters that are optimized can improve the mechanical properties of the products. These analyses are crucial, as they directly impact densification, porosity, and sintering behaviour, which in turn affect the mechanical properties of the final product.

INFLUENCE OF CHROMIUM SUBSTITUTION ON THE STRUCTURAL AND ELECTRICAL PROPERTIES OF MAGNESIUM TITANIUM PHOSPHATE CERAMIC ELECTROLYTES PREPARED VIA SOL-GEL METHOD

2025-12-04T09:57:11+00:00

Magnesium-based electrolytes have gained significant popularity recently among researchers as an environmentally friendly alternative to lithium electrolytes. In this study, Magnesium Titanium Phosphate with the substitution of Chromium, Mg_0.5+x/2Cr_xTi_2-x(PO₄)₃ceramic electrolytes were synthesized using the sol-gel method, with various x values. The impact of these x values of 0.1, 0.3, 0.5, 0.7, and 0.9 on the structural and electrical properties of the Mg_0.5+x/2Cr_xTi_2-x(PO₄)₃ samples was then investigated. X-ray Diffraction analysis revealed that the samples exhibited a hexagonal-shaped NASICON-type structure with R3c symmetry and some minor unidentified impurities across x values of 0.1, 0.3, 0.5, 0.7, and 0.9. Additionally, Fourier Transform Infrared analysis showed that the dominant vibrations in the samples came from the PO₄ tetrahedra. Microstructural analysis shows that increasing the Chromium content from 0.1 to 0.9 progressively refines the grain structure, resulting in smaller and more homogeneous grains. The electrical properties were then evaluated using Electrochemical Impedance Spectroscopy, revealing that the highest bulk conductivity of the samples occurred at x = 0.9 (8.97 x 10^-8 S.cm^-1), while the highest grain boundary conductivity of the samples was observed at x = 0.1 (4.66 x 10^-9 S.cm^-1). The greatest total conductivity of the samples was achieved at x = 0.1 with a value of 4.42 x 10^-9 S.cm^-1. Overall, the findings suggest that varying the x value significantly influences the structural and electrical properties of the Mg_0.5+x/2Cr_xTi_2-x(PO₄)₃ ceramic electrolytes.

EFFECT OF MICROCRYSTALLINE CELLULOSE LOADING AND TMPTA CROSSLINKING ON THE PROPERTIES OF LOW-DENSITY POLYETHYLENE COMPOSITES

2025-12-04T09:57:11+00:00

Low-density polyethylene (LDPE) is commonly used in packaging and industrial applications; however, it shows limited stiffness and poor interfacial compatibility with natural fillers. This study explores the integration of microcrystalline cellulose (MCC) sourced from coconut fibre and the use of microwave-assisted crosslinking with 3 wt.% trimethylolpropane triacrylate (TMPTA) to improve the mechanical and structural characteristics of LDPE composites. MCC was incorporated at 0–8 wt.%, and the composites underwent curing for 5 and 15 minutes. Mechanical, morphological, and structural analyses were performed through tensile testing, scanning electron microscopy (SEM), and X-ray diffraction (XRD), with each test repeated three times to ensure statistical reliability. The findings indicated that the composite with 6 wt.% MCC cured for 15 minutes demonstrated the highest tensile strength and elongation at break, due to efficient stress transfer and enhanced matrix–filler adhesion. SEM confirmed a uniform dispersion at this loading, whereas 8 wt.% MCC resulted in fiber agglomeration. The XRD results showed that MCC enhanced crystallinity, while the crosslinking induced by TMPTA resulted in a slight reduction due to restricted chain mobility. The combined effect of MCC reinforcement and controlled microwave-assisted crosslinking resulted in LDPE composites that exhibit enhanced mechanical integrity and structural stability. The optimal formulation for high-performance LDPE-based materials was established at 6 wt.% MCC and 3 wt.% TMPTA with a curing time of 15 minutes.

APPLICATION OF A DIY RGB-COLOR MOBILE PHONE MICROSCOPE IN THE STUDY OF BIOLOGY

2025-12-10T11:57:42+00:00

The microscope opens a window into the microscopic world, revealing details essential to the study of biology. However, it is typically costly and impractical for fieldwork. This research intends to develop a DIY RGB color enhancement for liquid and solid lenses to improve RGB color functionality, thereby supporting the application of mobile phones as microscopes in laboratories and fields. Lichens (family Graphidaceae), lichen moths (family Erebidae), and bagworms (family Tineidae) were selected as biological specimens for examination, and images were captured using liquid lenses, whereas the solid lenses consist of yeast (Saccharomyces cerevisiae), mung bean roots (Vigna radiata (L.)), and hydra (Hydra sp.). The experiment demonstrated that the liquid lens achieves a maximum magnification of 6.1X, while the solid lens reaches 100X magnification. Sample sizes suitable for studying liquid lenses range from 1 to 5 mm, whereas those for solid lenses range from 10 to 1000 μm. Therefore, liquid and solid lenses can serve as alternatives to stereo and compound light microscopes, respectively. The analysis of RGB values from photographs captured with liquid and solid lenses revealed statistically significant differences among specimens, particularly for those obtained using the green color filter. These images showed enhanced resolution, improved visualization of specimen features, and a sharper distinction between the specimen and the background. This study enables the creation of RGB color liquid and solid lenses using accessible and low-cost materials. These lenses can be applied to studies on biology and related specific fields, including zoology, plant biology, and microbiology. They facilitate the examination of the structures of animals, plants, and fungi, specifically in laboratories and fields.

MICROSCOPY OBSERVATIONS ON LEAF EPIDERMAL MICROMORPHOLOGY OF CONGEAROXB. AND SPHENODESME JACK (LAMIACEAE) FROM PENINSULAR MALAYSIA WITH TAXONOMIC IMPLICATIONS

2025-12-04T17:47:56+00:00

The leaf epidermal micromorphology provides important taxonomic characters for distinguishing closely related taxa within the family Lamiaceae. However, information on the micromorphological features of Congea and Sphenodesme species in Peninsular Malaysia remains limited. A micromorphological analysis of the leaf epidermis in five species belonging to the genera Congea and Sphenodesme was conducted to elucidate their generic and infrageneric relationships based on comparative epidermal traits. Microscopic observations were carried out using both light microscopy (LM) and scanning electron microscopy (SEM) to examine leaf micromorphological features, including epidermal cells, stomata, trichomes, and epicuticular wax, in Congea forbesii, C. griffithiana, Sphenodesme racemosa, S. pentandra, and S. triflora. The results showed that C. forbesii was clearly distinguished by its sinuous epidermal cells and amphistomatous leaves, in contrast to the hypostomatous condition observed in the other species. Variation in epidermal sculpturing on both leaf surfaces was recorded, with stomata predominantly flush except in S. racemosa, where they were slightly raised. Paracytic stomata predominated across the examined taxa, although interspecific variation in stomatal type and epidermal sculpturing provided additional diagnostic value. Trichome diversity also proved taxonomically informative, with stellate trichomes occurring uniquely in S. pentandra, while peltate trichomes were consistently present across all species. In addition, epicuticular wax occurred in two distinct morphological forms, namely thin rods and platelets, both contributing supplementary characters of taxonomic significance. These micromorphological traits serve as diagnostic characters for distinguishing Congea and Sphenodesme, further elucidating their taxonomic relationships within the Lamiaceae.

IMPACT OF BIOWASTE PORE-FORMERS ON THE PROPERTIES OF MULTI-DOPED CARBONATED HYDROXYAPATITE SCAFFOLDS

2025-12-04T09:57:12+00:00

Multi-doped carbonated hydroxyapatite, such as MgCoSr-CHA powders (md-CHA), has been developed as a potential alternative material for bone regeneration applications. This is due to their strong affinity for natural bone and good bioactivity, biocompatibility, and osteoconductivity properties. This study investigates the effect of incorporating biowaste as a pore-forming agent (BWPFA) on the structural and mechanical properties of md-CHA scaffolds. BWPFAs used in this study are (1) Empty fruit bunch (EFB) and (2) soybean hulls (SBH). Each BWPFA was milled for 3 hours, sieved to 150 μm, and mixed with md-CHA powders in a fixed ratio of 80:20. The scaffolds were then sintered at 800 °C to solidify the structure and ensure the complete removal of the BWPFA. Various techniques were employed, including X-Ray Diffraction (XRD) analysis, Fourier-Transform Infra-Red spectroscopy (FTIR), Field Emission Scanning Electron Microscopy with Energy-Dispersive X-ray spectroscopy (FESEM/EDX), density and porosity test, and diametral tensile strength (DTS) to characterize the scaffolds. Results confirmed that the scaffolds retained a single-phase CHA with a hexagonal crystal structure, and FTIR analysis verified the presence of B-type CHA. Adding BWPFA in the scaffold effectively creates scaffolds with an open pore structure with an optimal pore size of 200-300 μm, meeting the ideal bone scaffold’s requirements. Interestingly, different BWPFAs resulted in distinct pore shapes: elongated pores in EFB scaffolds and subrounded pores in SBH scaffolds, despite the initial particle size of EFB and SBH being similar. Scaffolds with SBH exhibited the highest porosity (15 %), followed by EFB (13 %), while the control had the lowest (5 %). As porosity increased, the DTS value decreased, with the control showing the highest strength (1.86 MPa), followed by EFB (1.09 MPa) and SBH (0.65 MPa).

ENHANCING CORROSION RESISTANCE OF WELDED METALS WITH SELF-HEALING COATINGS: EVALUATION OF EPOXY FORMULATIONS AGAINST MICROBIOLOGICALLY INFLUENCED CORROSION

2025-12-04T09:57:13+00:00

Corrosion of welded metals poses a significant challenge in industrial contexts, especially when joints are exposed to harsh environmental conditions. Although traditional corrosion protection methods, such as coatings, offer a cost-effective solution, their effectiveness can be undermined by aggressive corrosive agents or microorganisms. Recent advancements in self-healing coatings present a promising alternative, as these coatings can autonomously repair and prevent corrosion, thereby extending the service life of the metal. Microbiologically influenced corrosion (MIC), driven by microorganisms such as Pseudomonas aeruginosa, accelerates metal degradation in nutrient-rich simulated sea water medium (NRSS). This study aims to evaluate the efficacy of self-healing coatings in mitigating MIC on dissimilar welded metal substrates. Specifically, it assesses the performance of epoxy coatings incorporating 7 wt.% microcapsules and 10 wt.% chitosan particles compared to pure epoxy coatings. The coatings were applied to welded substrates and subsequently inoculated with Pseudomonas aeruginosa for 3, 7,14, 28 and 42 days immersion test. Field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS) were used to analyze biofilm formation, bacterial cell morphology, and corrosion precipitates. The results indicate that the self-healing coatings containing microcapsules and chitosan particles significantly improved corrosion protection, as evidenced by FESEM images showing reduced bacterial adhesion and biofilm formation. Chitosan particles, with their positively charged nitro-groups and high surface area, proved particularly effective in inhibiting biofilm development and exhibiting biocidal properties.

PHYSICO-MECHANICAL AND MORPHOLOGICAL ANALYSES OF ACTIVATED CARBON/CLAY REINFORCED RECYCLED POLYPROPYLENE COMPOSITES

2025-12-04T09:57:13+00:00

Plastic waste poses a significant environmental challenge due to its non-biodegradable nature and increasing global waste volume. Recycled polypropylene/clay (rPP/clay) composites typically exhibit inferior mechanical properties compared to virgin materials, limiting their practical applications. However, rPP/clay composites are still being investigated further due to their potential to enhance interaction with natural materials by improving their hydrophilic nature, making them valuable in construction applications. This study aims to enhance the properties of rPP/clay composites by incorporating activated carbon (AC). The rPP/clay/AC composites were prepared using a single screw extruder with varying AC contents (1 wt%, 7 wt%, 15 wt%, and 20 wt%). The physical and mechanical properties were evaluated, including density, flexural strength, flexural modulus, hardness, and morphological analysis. Results indicated that composite density varied with AC content, achieving a balance between mechanical strength and density. The composite with 7 wt% AC exhibited the highest flexural strength (63.04 MPa) and modulus (2.95 GPa), enhancing stiffness and resistance to bending. The added AC reinforced the polymer matrix, supporting a higher load-bearing capacity before failure. Morphological analysis showed no rupture under the flexural test for the composite with 7 wt% AC, indicating strong interfacial bonding and uniform distribution of AC within the polymer matrix. The FESEM images revealed a shear-yielding mechanism, contributing to the material’s enhanced toughness. At 20 wt% AC, the hardness reached 75.83, the highest value observed, indicating that higher AC percentages improve hardness, making the composite more resistant to indentation and surface deformation. These results suggest that AC/clay-reinforced plastic waste composites could be valuable for diverse applications, contributing to waste reduction and recycling efforts aligned with sustainable development goals.

COMPARATIVE PHYSICOCHEMICAL PROPERTIES OF BAMBOO-DERIVED ACTIVATED CARBONS FOR WASTEWATER TREATMENT APPLICATION

2025-12-09T06:30:34+00:00

Activated carbon (AC) is widely used in wastewater treatment due to its large surface area and pore volume, which enable efficient contaminant removal. Considerable research has focused on producing cost-effective AC from low-cost raw materials using physical or chemical activation methods. Chemical activation is generally preferred because it promotes the formation of larger pore structures and requires lower activation temperatures. In this study, three bamboo species: Bambusa vulgaris (BV), Gigantochloa scortechinii (GS), and Schizostachyum brachycladum (SB) were used to produce bamboo-based activated carbon (BAC) using sodium chloride (NaCl) as the activating agent. The physicochemical properties of the BAC produced through different activation procedures were compared, with activation carried out either before or after carbonization at room temperature. The influence of activation sequence on BAC properties was evaluated using density, porosity, iodine number, methylene blue adsorption, and scanning electron microscopy (SEM) analyses. The results showed that NaCl treatment significantly enhanced the iodine number of all bamboo-derived AC, achieving values within the commercial range (861–950 mg/g), along with high methylene blue adsorption capacities (384-441 mg/g). The activation procedures (before or after carbonization) did not markedly affect overall BAC performance. Among the tested species, Bambusa vulgaris activated after carbonization (ABV) exhibited the highest bulk density (0.29-0.40 g/cm³), porosity (73.59-83.71 %), iodine number (950 mg/g), and methylene blue adsorption capacity (441 mg/g). SEM images revealed that all bamboo-derived AC samples displayed porous structures under both activation procedures, confirming that ABV-based BAC possessed the most well-developed porosity. These findings demonstrate that NaCl-assisted chemical activation effectively produces high-quality BAC from bamboo, offering a sustainable and economical adsorbent suitable for wastewater treatment applications.

STRUCTURAL AND COMPOSITIONAL EFFECTS OF CELLULOSE NANOFIBER–GRAPHENE/BI₂TE₃ NANOCOMPOSITE FILMS FABRICATED BY ELECTRODEPOSITION

2025-12-04T09:57:14+00:00

Cellulose nanofiber (CNF) is a naturally derived nanomaterial known for its low thermal conductivity, making it an eco-friendly candidate for thermoelectric applications. This study explores the development of a CNF–graphene/Bi₂Te₃ nanocomposite thermoelectric material fabricated via electrodeposition using a three-electrode potentiostat setup. Electrolyte solutions containing nitric acid, bismuth-telluride ions, graphene, and varying CNF concentrations (0.5–2.0 g/L) were prepared to investigate CNF incorporation. The resulting films exhibited uniform distribution of CNF and graphene, with CNF content reaching up to 7.17 wt%. The Bi/Te atomic ratio remained stable (within 3.0 % of the stoichiometric Bi₂Te₃ phase), and the average grain size was reduced by ~35 % compared to pristine Bi₂Te₃ , enhancing phonon scattering and electron mobility. X-ray diffraction (XRD) confirmed the rhombohedral Bi₂Te₃ (R3-m) structure with characteristic (1010), (015), and (110) peaks. No CNF or graphene peaks were detected, indicating successful incorporation without the formation of separate crystalline phases. Increasing CNF content reduced and broadened the (1010) peak, with crystallite size decreasing from 32.2 nm to 21.3 nm (CNF–III). A slight shift toward higher 2θ in CNF–III suggests interfacial strain and hybrid structural interactions. These structural modifications—grain refinement, disrupted long-range crystallinity, and interfacial effects—are expected to enhance thermoelectric performance by reducing lattice thermal conductivity and improving charge transport. The CNF–graphene/Bi₂Te₃ hybrid film thus demonstrates strong potential for next-generation thermoelectric materials.

EFFECT OF CU PARTICLES CONTENT ON THE SURFACE MORPHOLOGY AND MECHANICAL PROPERTIES OF NI-CU COMPOSITE COATING

2025-12-10T11:52:51+00:00

Nickel (Ni) coating is commonly used in many industrial applications. Still, the challenge has recently been encountered when Ni coatings experience aggressive stress and load, while their durability may not be sufficient to maintain performance in such conditions. Thus, Ni composite coating offers significant improvement in terms of mechanical properties and wear resistance. Therefore, in this study, metallic particles, such as copper (Cu) particles, can be added to Ni composite coating to refine the coating structure while increasing its durability. However, the conductivity of Cu particles in the electrolyte may influence the surface morphology while contributing to increasing the hardness of the composite coating. Thus, this study aims to determine how optimal Cu particle concentration influences coating surface morphology and hardness. The Cu particles in a range of 0.1–5 g/L were deposited in the Ni matrix, and the growth of composite coating was observed based on deposition times of 5, 10, 20 and 30 minutes. The coated surfaces were examined by surface morphological analysis, and mechanical properties were determined through microhardness testing. The result showed that the formation of a broccoli-like structure increased as the concentration of Cu particles in the Ni composite coating increased. The result also revealed that the higher hardness of Ni-Cu composite coating was achieved when 1 g/L of Cu was loaded into the electrolyte bath. Meanwhile, based on a growth study, Ni ions prefer to be deposited on the carbon steel substrate and at the Cu particles at the early stage of 10 mins. Subsequently, as time increased, Ni-coated Cu formed an accumulated, broccoli-like structure and was incorporated into the growing Ni deposits.

FAILURE ANALYSIS OF NATURAL GAS FUEL SUPPLY TUBES IN POWER PLANT COMBUSTION SYSTEMS

2025-12-04T09:57:15+00:00

Failures in natural gas fuel supply systems are often linked to the combined effects of material degradation, operational factors, and improper installation practices. In this study, the primary cause was identified as an installation error at the tube bend, leading to condensation-induced corrosion. Rapid temperature and pressure fluctuations during shutdowns created ideal conditions for moisture accumulation, particularly at the bend, which accelerated corrosion. The failure mechanisms involved stress corrosion cracking (SCC), sulfide stress cracking (SSC), hydrogen embrittlement (HE), and localised pitting corrosion. The presence of hydrogen sulfide (H₂S) and trace amounts of chlorides in the natural gas further intensified the degradation. The methodology included visual inspection, chemical composition analysis, stereomicroscopy, optical microscopy, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). These analyses identified the extent of condensation-induced corrosion and the failure points. Results confirmed that the tube bend geometry contributed to moisture retention, exacerbating the corrosion process. Although AISI 304 stainless steel is suitable for general applications, it performs poorly in environments with moisture and condensation, as these promote passive film breakdown. Rapid temperature and pressure drops during shutdowns enhanced moisture condensation and corrosion under the influence of corrosive gases. The discussion highlights the need to redesign the tube bend geometry, adopt corrosion-resistant materials such as AISI 316L or AISI 321 stainless steel, and implement stress-relief and inspection techniques. Addressing the installation error, material selection, and operational practices will help prevent future failures and ensure long-term performance.

ANATOMICAL AND MICROMORPHOLOGICAL CHARACTERISTICS OF LEAF EPIDERMIS OF SELECTED SPECIES OF Hoya R.BR. (APOCYNACEAE) IN PENINSULAR MALAYSIA

2025-12-04T09:57:15+00:00

Leaf anatomy and micromorphology studies were conducted on ten selected Hoya species in Peninsular Malaysia, namely H. archboldiana C.Norman, H. bhutanica Grierson & D.G.Long, H. glabra Schltr., H. halconensis Kloppenb., H. hanhiae V.T.Pham & Aver., H. limoniaca S.Moore, H. mindorensis Schltr., H. multiflora Blume, H. paziae Kloppenb. and H. pubifera Elmer. This study aims to identify the common characteristics, variations, and diagnostic features of leaf anatomy and micromorphology in the studied Hoya species and to construct a dichotomous key for species identification. This study involved epidermal screening techniques for abaxial and adaxial epidermal observations of leaves, while micromorphological observations involved gold coating, critical point drying, and examination with a scanning electron microscope. Common characteristics observed include the presence and distribution of stomata, leaf margin patterning, and the pattern of anticlinal walls on the leaf's epidermal surface. Variable characteristics include the type of wax, cuticle engraving on the leaf epidermis, structural composition, margin, shape, size, stomatal index, trichomes, leaf margins, starch nodules, and crystals. Diagnostic features identified include the leaf epidermal wax type and starch nodules, the structure of stomata, and trichomes. A dichotomous key for species identification can be developed. This study's results demonstrated that the leaves' anatomical and micromorphological characteristics hold taxonomic significance for identifying, differentiating, and classifying the Hoya species studied.

THE EFFECTS OF OVEROXIDATION ON THE MORPHOLOGICAL AND ELECTRICAL PROPERTIES OF POLYANILINE (PANI) BASED SOLID POLYMER ELECTROLYTE (SPE)

2025-12-04T09:57:15+00:00

Overoxidation in lithium-ion batteries (LIBs) can occur when a solid polymer electrolyte (SPE) undergoes extreme oxidation, forming undesirable functional groups like carbonyl and hydroxyl. This work examines the effects of overoxidation on polyaniline (PANI)-based SPEs, focusing on morphological, electrical, and structural changes. SPE films composed of PANI, polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) were prepared with varying PANI concentrations (1 wt.%, 3 wt.%, and 5 wt.%) and subjected to overoxidation via cyclic voltammetry (CV). Fourier-transform infrared spectroscopy (FTIR) was used to characterize the structural changes, while electrochemical impedance spectroscopy (EIS) assessed electrical conductivity. The highest initial conductivity (1.8×10^-5 S/cm) was observed in the composite with 1 wt.% PANI, decreasing to 1.79×10^-6 S/cm after overoxidation. Composites with 3 wt.% and 5 wt.%. PANI exhibited lower initial conductivities of 1.41×10^-6 S/cm and 1.25×10^-6 S/cm, respectively, which further dropped to 4.17×10^-7 S/cm and 1.79×10^-7 S/cm post-overoxidation. Field-emission scanning electron microscopy (FESEM) revealed that the interpenetrating polymer network (IPN) structures present before treatment were disrupted after overoxidation. FTIR confirmed the formation of hydroxyl and carbonyl species, which correlate with reduced conductivity and degradation of the SPE material. These findings illustrate the detrimental effects of overoxidation on PANI-based SPEs, impacting their structural integrity, morphology, and electrical performance. This has significant implications for LIB efficiency and highlights the importance of mitigating overoxidation in SPEs.

MICROPLASTICS IN THE SHORTFIN SCAD DECAPTERUS MACROSOMA FROM THREE SELECTED WET MARKETS, SABAH

2025-12-04T09:57:16+00:00

Microplastics (MPs) have become a major concern as a source of environmental pollutants in marine ecosystems. Fish such as shortfin scad are consumed daily, particularly in Sabah and an important protein source. It is also being used as feed for marine finfish such as grouper. This study aimed to characterize the types of MPs isolated from Decapterus macrosoma from three selected wet markets at Sabah. A total of 21 specimens of fish were collected from three selected wet markets, respectively, around Kota Kinabalu. The fish were dissected, and their gastrointestinal tract (GIT) and flesh were separated for digestion. The exudates were filtered several times using filter paper. MPs isolated were characterized using microscopes and the polymers were identified using Fourier Transform infrared spectroscopy (FTIR). The MPs were measured using ImageJ software. The total MPs collected from both organs was 1541. Pasar Ikan Tuaran specimens recorded the most MPs in flesh (n=263) and GIT (n=422). The most abundant shape was fiber (n=1406, p<0.05) and the most significant color was black (n=866, p<0.05). The polymers that were detected from both GIT and flesh were polyamide (n=39), followed by polycarbonate (n=21) and poly(methyl methacrylate) (n=11). In conclusion, the MPs were found in the flesh and GIT of D. macrosoma with the majority from polycarbonate and PMMA. These results show concern about seafood safety in Malaysia with regard to Sabah.

EXPLORING THE EFFECT OF DIFFERENT DILUENTS AND DILUTION RATIOS ON MICROALGAE GROWTH IN LANDFILL LEACHATE

2025-12-04T09:57:16+00:00

The escalating discharge of landfill leachate presents significant environmental challenges, posing serious risks to ecosystems and public health. Leachate is characterised by its complex composition, high toxicity, and significant pollutant load, making its treatment and disposal a persistent issue for waste management systems worldwide. However, its nutrient-rich nature, including high concentrations of nitrogen, phosphorus, and trace elements, suggests it could be repurposed as a resource rather than merely treated as waste. This study explores the use of landfill leachate to culture Chlorella sorokiniana, focusing on its ability to support microalgae growth and enhance biomass productivity. Specifically, the study examines Chlorella sorokiniana growth in media derived from three different leachate treatment ponds (raw pond, Sequencing Batch Reactor Pond, and Dissolved Air Flotation Pond) and also investigates the growth of leachate in various diluents, including tap water, lake water, grey water, and rainwater. The best diluent is selected based on its characteristics and ability to support microalgae growth. It was subsequently used to dilute the leachate at concentrations of 25 %, 50 %, 75 %, and 100 % (v/v). Findings revealed that leachate from the raw pond provides the most suitable conditions for microalgae growth due to its balanced organic content, moderate suspended solids, low colour and suitable pH. Microalgae cultivated in this medium outperformed the other two ponds, achieving the highest specific growth rate (0.52 /day), cell division rate (0.75 divisions/day), and biomass productivity (14.17 mg/L/day). Analysis of diluents showed that tap water was the most favourable medium for microalgae cultivation, and when used to dilute leachate to 25 %, it provided optimal growth by minimising inhibitory effects. These findings underscore the critical role of leachate composition, diluent selection, and dilution in optimising microalgae-based treatment technologies.

INVESTIGATION ON THE CRYSTALLOGRAPHY AND MORPHOLOGY OF LITHIUM COBALT MANGANESE TETROXIDE SYNTHESISED AT LOW TEMPERATURE WITH VARIOUS LITHIUM PRECURSORS

2025-12-04T09:57:17+00:00

Spinel structured lithium cobalt manganese tetroxide (LiCoMnO₄) which exhibit reduction potential ranging between 5.1 – 5.6 V (vs. Li⁰ | Li⁺) was identified to be one of the prospective cathode candidates for next generation lithium-ion electrochemical systems offering unprecedented voltage output. This article highlights the significance of lithium precursor towards the crystallography and morphology of lithium cobalt manganese tetroxide (LiCoMnO₄). LiCoMnO₄ cathode compounds in this research were synthesised via sol-gel reaction with stoichiometric ratio of Li:Co:Mn maintained at 1:1:1. The sol-gel formed were subsequently converted into xerogel before subjected to facile one-step low temperature calcination protocol at 600 ˚C. The source of lithium was derived from four distinctive precursors, namely lithium acetate dihydrate (LiCH₃COO⸳2H₂O), lithium carbonate (Li₂CO₃), lithium fluoride (LiF) and lithium hydroxide monohydrate (LiOH⸳H₂O) respectively. Co-existence of multiple phases were detected within the resultant compound synthesised with LiCH₃COO⸳2H₂O, Li₂CO₃ and LiOH⸳H₂O being used as lithium precursor. X-ray diffraction coupled with Rietveld refinement revealed that single phase LiCoMnO₄ compound was attained from the post-calcinated specimen synthesised with LiF being used as the source of lithium. The adoption of LiF as lithium precursor also resulted in the formation of LiCoMnO₄ compound with relatively homogenized grain size as observed from field emission scanning electron microscopy (FESEM).

PREPARATION AND CHARACTERIZATION OF PLA/HAp COMPOSITE FOR BIOMEDICAL APPLICATIONS

2025-12-09T06:29:48+00:00

Producing scaffolds using hydroxyapatite (HAp) presents several challenges, including difficulties in controlling porosity, achieving desired mechanical properties, and addressing the brittle nature of HAp. Polylactic acid (PLA) and HAp composites with various mixing ratio were produced by an internal mixer brabender to create excellent biocompatible and biodegradable scaffolds for biomedical applications. The properties of pure PLA and PLA/HAp composite were analyzed in morphological structure, thermal stability, functional groups, and surface roughness using a scanning electron microscope (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM), respectively. SEM images combined with energy dispersive spectroscopy (EDS) showed porous materials with fine grains. Pure PLA showed the presence of carbon (C) and oxygen (O) peaks while PLA/HAp composite shows the presence of additional elements which are calcium (Ca) and phosphorus (P). Meanwhile, TGA results showed the value of peak decomposition temperature decreases with the decreasing composition of PLA in the composite. The functional groups assessment showed the presence of a carbonyl group (CO) and C-H bonds for pure PLA, while the PLA/HAp composite showed the presence of additional phosphate groups. In terms of surface roughness, AFM showed increasing amounts of HAp in the PLA matrix lead to an increase in the average roughness, which can lead to better cell attachment to the composite. The results indicated that the composite with a PLA/HAp weight ratio of 70/30 accomplished more favorable properties for biomedical applications.

WETTABILITY TUNING OF CANDLE SOOT COATED 3D-PRINTED MEMBRANES VIA LASER POWER CONTROL

2025-12-09T06:28:31+00:00

Three-dimensional (3D) printing has attracted growing interest for the fabrication of membranes for oil-water separation. While laser power is a key parameter in membrane fabrication, its effect on the wettability of coated membranes is still not well understood, posing challenges for improving membrane performance. This study investigates the effect of laser power on the wettability of 3D-printed polymer membranes coated with candle soot. Membranes were fabricated from virgin polyamide-12 (PA-12) powder using Selective Laser Sintering (SLS) at two laser power settings: 70 W and 80 W and then coated with candle soot. Characterization of membranes involved surface morphology, roughness, water contact angle, mechanical strength and mechanical and chemical stability. Notably, the coated membrane produced at lower laser power of 70 W demonstrated the highest water contact angle (150.7 ± 1.8°), attributed to the lower energy density which led to inefficient powder melting and sintering. In contrast, higher laser power (80 W) produced smoother surfaces and slightly improved tensile strength due to more efficient powder sintering. Mechanical durability remained stable across both settings while chemical stability of the coated membranes showed greater sensitivity to abrasion, likely due to post-printing coating application. These findings underscore the critical importance of optimizing laser power to precisely control membrane characteristics and thereby enhance the efficiency of oil-water separation.

THE EFFECT OF SEQUENTIAL WASHINGS ON MORPHOLOGICAL PROPERTIES OF COTTON FABRIC SURFACE PROTRUSION

2025-12-04T09:57:18+00:00

Repeated washings on the textiles has abraded the material surface which contributed to the release of
the microfibres into the wastewater. The evaluation on fabric surface is important because the protrusion formed acts as the intermediate state before microfibre release could happen and natural fibres such as cotton have a significant contribution towards such situation. Hence, the main aim of this study is to investigate the protrusion of woven cotton fabric through microscopic image observation with Scanning Electron Microscopy (SEM), which was then analysed with imageJ software. The relationship between the cotton fabric protrusion properties with the number of washing cycle intervals were explored. A sample of 100 % cotton woven fabric has been washed for 25 times with a lab-scale washer, and the protrusion length, void space and protrusion coverage image were investigated for every five washings interval. It was found that the length of the fabric protrusion increased within the 25 washing cycles by total up to 30 %, the void space reduced by 2.31 % whilst the protrusion coverage increased by 3.09 % after the sequential washes which showed that there was an effect on the fabric protrusion due to the washing activities. A thorough study on the fabric protrusion of cotton fabric
would provide a clear understanding on one of the root causes of the microfibre release issue and be the
reference or the starting point in the creation of an anti-microfibre-release finish based on the fabric protrusion
characteristic.

MICROSTRUCTURE, SURFACE ROUGHNESS AND VICKERS HARDNESS ANALYSES OF MISWAK REINFORCED DENTAL COMPOSITE

2025-12-04T23:48:13+00:00

Despite the widespread use of dental composites, their mechanical properties and surface characteristics can sometimes fall short of clinical expectations, potentially affecting long-term durability and overall performance. Miswak, a natural product with known oral health benefits, has been proposed as a novel reinforcement agent to improve composite properties. This study investigated the effects of miswak on the microstructure, surface roughness, and Vickers hardness (VHN) of dental composites. Specimens were prepared in the following groups: negative control (no miswak), 1 wt% miswak, 3 wt% miswak, and positive control (Filtek™ Z350XT, 3M ESPE). Scanning electron microscopy (SEM) was used to examine the microstructure, while surface roughness and VHN were assessed using a profilometer and hardness tester, respectively, under standardised laboratory conditions. Data were analysed with one-way ANOVA and post-hoc Tukey's test. SEM analysis showed a homogeneous miswak distribution in all groups. The 3 wt% miswak group exhibited significantly lower surface roughness than the other groups (p < 0.05). The 1 wt% and 3 wt% miswak groups showed increased VHN compared to the negative control, but no significant difference was found between the 1 wt% and 3 wt% groups (p > 0.05). These results suggest that miswak reinforcement can improve the surface roughness and VHN of dental composites without compromising the resin matrix’s homogeneity.

FABRICATION AND PHYSICOCHEMICAL PROPERTIES OF ALGINATE-COFFEE BIOFILM FOR WOUND HEALING APPLICATION

2025-12-04T09:57:18+00:00

Alginate is extracted from seaweed with a gel-forming abilities was used to combined with coffee’s bioactive compounds to enhance its potential that could be useful for biomedical applications. To achieve the desired mechanical strength, stability of biofilms and overcome the issue of sustainability, the alginate/coffee biofilms were fabricated, by sodium alginate diluting in distilled water at percentage 1w/v and ground coffee Robusta was added to that solution at weights of 0.1 g, followed with the solution casting process and cross-linked with different time with calcium chloride solution at a concentration of 0.1 M. Scanning electron microscopy (SEM) analysis shows alginate/coffee biofilm of coffee weight 0.1 g, resting for 1 hour before crosslinking have the formation of loose-packed crystal structure. Energy dispersive X-ray (EDX) spectroscopy result showed compositional outcome are O, Na, Cl and Ca at the Alginate/coffee biofilm. Fourier transform infrared spectroscopy (FTIR) analysis of alginate/coffee biofilm of coffee weight 0.1 g, resting for 1 hour before crosslinking verifies the appearance of absorption band at a wavenumber of 3264.95 cm^-1, 1597.90 cm^-1 and 1023.07 cm^-1 indicate the presence of functional group of alginate and coffee. Atomic force microscopy (AFM) showed surface roughness of alginate/coffee biofilm of coffee weight 0.1g with resting time 1 hour before crosslinked was 124.155 nm, respectively. It was found the rougher the surface enhances the adhesiveness properties of the film to the wound site. Hydrophilicity properties were determined by contact angle testing to show it is suitable for absorbing any liquid from the open wound. Alginate/coffee biofilm samples showed hydrophilicity properties as the contact angle was less than 90 degrees. This study offers insight the suitability of the chosen material for biomedical application in the wound healing process.

MORPHOLOGICAL AND STRUCTURAL STUDIES OF IRON OXIDE-CNT NANOCOMPOSITES BY ROBUST OXIDATION

2025-12-04T09:57:19+00:00

Heavy metals in wastewater pose a significant risk to the environment and human health due to their aquatic toxicity. This study investigates the optimal temperature for thermal oxidation to produce iron oxide nanowires and examines the adsorption capabilities of iron oxide-CNT (carbon nanotube) nanocomposites for heavy metal ions removal. Iron oxide nanowires facilitate magnetic separation post-adsorption, while CNTs provide a large surface area for the metal ion attraction. The iron oxide nanowires are synthesized through thermal oxidation, and the nanocomposite is formed via spin coating. Morphological and structural properties are analysed using Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), and Raman spectroscopy. The morphological studies show that the formation and properties of iron oxide nanowires can significantly vary with oxidation temperature. Temperatures between 450 °C and 650 °C have shown to produce a different crystalline peaks and morphologies. Thus, indicate that the formation and quantity of iron oxide nanostructures may vary with temperature. Meanwhile, adsorption capabilities of lead ions are assessed with UV-Vis spectroscopy by measuring the absorbance of heavy metal ions at specific wavelengths. With usage of the iron oxide- CNT nanocomposite, the absorption of the lead ions increases with longer immersion times. Thus, the iron oxide-CNT nanocomposites produced in this study has high potential for applications in wastewater treatment.

PLA/TIO₂ NANOCOMPOSITES: PREPARATION, CHARACTERIZATION, ANTIBACTERIAL AND CYTOTOXICITY EVALUATION FOR FOOD PACKAGING

2025-12-04T09:57:19+00:00

Poly (lactic acid) (PLA) is a polymer with promise for various applications, including food packaging and engineering composites. However, PLA is not appropriate for several applications due to its comparatively weak mechanical and thermal properties. The mechanical and thermal properties of PLA can be enhanced by combining it with other materials. The current study has two objectives: first, to synthesize and characterize PLA/titanium dioxide (TiO₂) nanocomposites using a solvent-casting method. The second objective of the present work was to evaluate the biomedical properties of the modified composites using antibacterial and cytotoxicity studies. The methodology part of the present study includes preparing five samples with different PLA:TiO₂ ratios and characterizing them using a field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), and dynamic mechanical analysis (DMA). The biomedical properties were evaluated using antibacterial activity against Streptococcus pyogenes (S. pyogenes) and Salmonella. Moreover, cytotoxicity of the prepared samples was evaluated using the MTT assay. The results show that the surface morphology of the PLA/TiO₂ nanocomposites was observed in FESEM as a homogeneous dispersion of TiO₂ nanoparticles in a PLA matrix. Moreover, particle size was measured from SEM images, and the prepared samples showed an average particle size of 27 to 63 nm. The storage modulus of the composites augmented with increasing filler loading, whilst the glass transition temperature decreased from 61.7 to 59.6 °C. The prepared composites showed a significant effect against Streptococcus pyogenes and Salmonella. Moreover, the cytotoxicity test showed higher cell viability against the HEK293 cell lines. The amalgamation of PLA and TiO₂ nanofiller has significant promise for food packaging applications.

A BIBLIOMETRIC ANALYSIS OF 3D PRINTING FOR BONE TISSUE REGENERATION

2025-12-04T09:57:20+00:00

3D printing technology in tissue regeneration discipline played a pivot role in the sustainable growth of human healthcare. Publication based on 3D printing and tissue regeneration discipline has exhibited an exponential growth due to the vast expansion of the research output. In regard to current publications, the authors investigated the trends regarding 3D printing technology in tissue regeneration discipline, focusing on bone. An analysis using the keywords “3D printing” and “bone tissue regeneration” revealed that 261 papers were published between 2015 and 2024. The number of publications on these topics increased significantly, raising from 2 in 2015 to 70 in 2024. The materials extrusion, directed energy deposition, powder bed fusion, materials jetting, and photopolymerization were currently the most often types of technology used to produce 3D biomedical products related to bone tissue regeneration. Meanwhile, metal, polymer, ceramic, composite, smart material, and special material were the most frequently used materials as matrix or filler in biomedical 3D printing technology. Studies in the current literature reveal that composites are favored due to material properties that can be customized to meet specific requirements including mechanical strength, heat resistance, flexibility, and chemical resistance. The Chinese government has strategically invested in regenerative medicine and 3D bioprinting to address healthcare challenges and position the nation at the forefront of medical innovation. As for method, fused deposition modeling (FDM) is frequently chosen among researchers due to cost-effectiveness, user-friendly and compatibility to wide range of thermoplastic materials. This review will provide significant support by offering scientific insights to assist future research in the field of tissue regeneration.