Papers by Keyword: Morphology

Abstract: The demand for environmentally sustainable methods to enhance the performance of low-carbon steel (LCS) has led to increased interest in organic waste-derived carburizing agents. This study explores the potential of using a blend of Shea Nut Shell (SNS) and Eggshell (ES) ash, mixed in a 1:3 ratio, as an eco-friendly carburizing medium for improving the mechanical and corrosion-resistant properties of LCS. Carburization was carried out at 900°C for 30 minutes, and the effects were assessed through comprehensive characterization. Mechanical properties such as hardness, tensile strength, and impact energy were evaluated alongside microstructural analysis using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and wear rate testing. Corrosion resistance was investigated in H₂SO₄ and NaCl environments over a 21-day period. Results show that carburized LCS achieved significantly higher hardness (514.55 HB) compared to the uncarburized counterpart (399.05 HB), with improved toughness as indicated by increased impact energy absorption. However, un-carburized LCS maintained higher tensile strength. Microstructural examination revealed enhanced carbon diffusion and pearlite formation, contributing to reduced wear in carburized samples. EDS confirmed increased surface carbon content, while corrosion behavior varied: carburized LCS performed better in saline (NaCl) conditions, whereas uncarburized LCS offered better resistance in acidic (H₂SO₄) environments. In conclusion, the SNS-ES ash mixture presents a promising route for sustainable carburization of LCS, particularly for components exposed to saline environments such as agricultural tools and automotive parts. Future work will focus on optimizing treatment durations, expanding corrosion testing in simulated service environments, and scaling the process for industrial applications.

Abstract: This study investigates the potential of typha domingensis fibers to be used as reinforcement in composite materials. Morphological, mechanical, and thermal analyses were conducted on fibers extracted from leaves and stems using various methods. The leaf fibers (LNF-00, LRD-41, LRS-41), with transverse dimensions ranging between 185 to 244 µm, were on average 48% thinner than stem fibers (SNF-00, SRD-20, SRS-20), whose transverse dimensions ranged from 305 to 334 µm. Transverse dimensions variations were most pronounced for fibers retted in distilled water (65%), followed by those retted in seawater (47%) and mechanically processed fibers (37%). Stem fibers subjected to seawater retting (SRS-20) exhibited less dispersion in mechanical properties, with a Young’s modulus of 2.2 GPa and a tensile strength of 55.9 MPa. Overall, leaf fibers outperformed stem fibers, with average increases of 38, 60, and 31% for Young’s modulus, tensile strength, and elongation at failure, respectively. Finally, thermal analysis revealed that fibers retted in distilled water provided the highest thermal stability, attributed to a reduction in lignin and hemicelluloses.

Abstract: This study investigates the effect of Sr (0.1, 0.15, and 0.2 wt.%) modification on the microstructure and morphological evolution of the in-situ Al-15%Mg₂Si-4.5%Si composite. The composites are developed via Low superheat casting (LSC) technique, at the onset of gravity, and subsequently characterized through optical microscope, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Electron Probe Microprobe Analysis (EPMA), and XRD texture analysis. It is found that, with the increase of Sr content in the Al-15%Mg₂Si-4.5%Si composite, the morphology of primary Mg₂Si particles changes from irregular dendritic and hopper structure to nearly perfect cubic morphology. The addition of 0.2 wt.% Sr reduces the average primary magnesium silicide (Mg₂Si) particle size from ~56 µm to 36 µm and the Al grain size from ~63 µm to ~44 µm, indicating significant refinement. The XRD texture analysis through Orientation Distribution Function (ODF) reveals that the cubic texture and rotated cubic texture are the predominant orientations for Al and Mg₂Si phases, respectively. However, the composite modified with 0.2 wt.% Sr exhibits a weak texture and more random grain distribution, highlighting the role of Sr in reducing grain size and promoting uniformity. These findings underscore the potential of Sr addition to enhance the microstructural and mechanical properties of Al-15Mg₂Si-4.5Si composites for advanced applications.

Abstract: White-beam X-ray sectional topography enabled the successful evaluation of the quality of anthracene single crystals grown by the physical vapor transport technique; however, such single crystals exhibited a thin plateletlike configuration and their quality is difficult to evaluate in the cross-sectional direction. The experimental results showed that the anthracene single crystals grown by the physical vapor transport technique maintained their high quality; however, they tended to have widespread hollows inside owing to their specific configuration.

Abstract: Pyrolytic technology was developed to grow Zn-based nano- and microstructures. It was based on the application of a mixture of ammonium chloride, Zn and ZnO powders as source materials. Two temperature profiles were used for the synthesis. In the first and second growth processes, the maximum substrate temperatures of 250 and 410°C were reached, respectively. The granular layer of micrometer range ZnO crystals was produced in the first process. By depleting the source with NH₄Cl, the Zn polyhedra, and layered spheres were produced within 50–65 min in the second process. By increasing the NH₄Cl content in the source to 0.9 g, the Zn/ZnO core–shell spheres were synthesized. The further increase of process duration led to the out-diffusion of Zn from the core, its oxidation, and the formation of a thick, dense ZnO spherical shell. Even further annealing in residual gases caused the increase of the Zn vapor pressure inside the shell. As a result, at a certain Zn vapor pressure, the shell bursts, causing the formation of a hollow ZnO microsphere.

Abstract: This paper presents an experimental study on the influence of solidification cooling rate on the evolutions of microstructural morphologies of a high strength low alloy steel. To this end, solidification samples (cylindrical form with 10 mm diameter and 120 mm length) were prepared from 30 cm below the ingot/hot-top interface, at the center, of a 40 MT (Metric Ton) ingot. Solidification experiments were carried out by using Gleeble^® 3800 thermo-mechanical simulator. Two solidification cooling rates of 1 and 50°C/s were chosen. For microstructural characterization, samples were prepared by mounting, polishing and etching with 3% Nital solution. Also, an optical microscope was employed for microstructural observations. The obtained results showed that for 1°C/s, the microstructure is composed with dendrites and grains. Here, the grain morphology is the dominant one. In the case of 50°C/s, the dendrites were localized at the sample surface and the grains were present more into the depth of the sample. Moreover, the increase of solidification cooling rate results in finer dendrites. The results are discussed in the framework of solidification mechanisms.

Abstract: Synthetic foam will negatively impact the environment and living beings. To solve this issue, synthetic materials may be substituted with more eco-friendly materials, such as foam derived from bamboo. The structure of bamboo and the substances inside make it highly useful for various applications. This research produced a biodegradable foam from the difference in weight fraction of cellulose derived from bamboo. The Kraft pulping process has been used to remove lignin and to get cellulose from bamboo (Bambusa vulgaris). The foam substance was produced by combining starch and cellulose derived from bamboo with chemical ingredients such as sodium chloride, sodium dodecyl sulfate, glycerin, and sodium hydrogen carbonate. Cellulose bio-foam (CBF) derived from bamboo were characterized by Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDX). Scanning electron microscopy is a powerful technique that allows for evaluating surface morphological changes. When SEM is combined with the EDX technique, it can provide valuable input in determining the distribution of various elements on the surface. The results of SEM - EDX spectra have shown that essential elements like Carbon (C), Oxygen (O), Sodium (Na) and Chlorine (Cl) were present in the cellulose bio foam (CBF). These findings indicate that cellulose bio foams (CBF) derived from bamboo have the potential to be used in a wide range of commercial applications in substitution of synthetic foam materials.

Abstract: There are abundant silica sand resources in Malaysia, however many have not yet been fully discovered. The primary component used in the production of glass is silica sand. The objective of this research was to determine whether local silica sand might be used to make coloured glass. The chemical composition and mineralogy of silica sand were determined using X-ray fluorescence (XRF) and X-ray diffraction (XRD), respectively. The physical properties such as particle size distribution were determined by using a mechanical shaker whereas grain morphology was identified by using a digital microscope. Additional equally significant properties such as moisture content, clay content, pH value and the specific gravity of silica sand were also measured by using standard laboratory testing method. The obtained results were compared to Malaysian Standard MS 701:2017, the standard specification for the production of coloured glass. From XRF analysis, the silica sand contained silicon dioxide at a concentration of 97.84%, alumina at 0.56%, iron oxide at 0.12% as well as several other oxides at around 1.5%. XRD diffractogram also revealed that quartz is a major constituent having the highest peaks at about 26.7° with an intensity of 13,7786. More than 95% of the particle sizes of the silica sand are in the size range from 150 µm to 1000 µm and in the category of fine sand and coarse sand. The grain shape was determined to be angular, and the silica sand had a moisture content of 2.54%, a clay content of 7.80%, a pH value of 5.93, and a specific gravity of 2.63. Based on the chemical and physical properties, it appears that this particular silica sand satisfies the standard requirements for coloured glass production.

Abstract: Undoped and Ni-Eu co-doped ZnO thin films were successfully fabricated via spray pyrolysis at 400°C. The impact of co-doping on the structural, morphological, electrical, and optical properties of the thin films was thoroughly investigated. X-ray diffraction (XRD) analysis confirmed the absence of secondary phases and verified the successful incorporation of dopant ions into the ZnO lattice. Morphological examination revealed enhanced crystallization and a more uniform surface following the incorporation of nickel. Spectral studies in the UV-Vis region were conducted to determine the optical band gap of the synthesized ZnO films, indicating a slight decrease in bandgap values and volume and surface energy losses (VELF and SELF) with increasing Ni doping concentration. Photoluminescence spectra exhibited emission peaks in the UV region around 415 nm and broad visible emissions spanning 450-650 nm for all samples. Electrical characterization using Hall Effect measurements confirmed n-type electrical conductivity in all prepared films, as evidenced by the observed negative Hall coefficients. The co-doped ZnO thin films, particularly those incorporating Ni-Eu, show promise for applications in electronic and optoelectronic devices. Additionally, we investigated the photodegradation of green malachite under a UV lamp. Remarkably, the results demonstrated degradation rates of 93% within 2 hours, showcasing promising potential for practical applications.

Abstract: This research identification gel types of the modified-recycled poly (ethylene terephthalate) (modified-rPET) filament, with and without the addition of heat stabilizer Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox®1010). This research also identifies the gel types and studies thermal behavior of the modified-rPET filaments above, by using a hot-stage microscopy, and a differential scanning calorimetry, respectively. rPET flakes were dried to deplete the moisture. Then, they were mixed with additives and heat stabilizer (Irganox®1010) at 0 and 0.5 pph, Then, they were extruded to be compound using twin screw extruder. The compounds were extruded into filament by using filament extruder. The two temperature profiles were used. The first and the second temperature profiles from the feed zone to the die zone were 275-275-275 ^oC and 290-290-290 ^oC, respectively. The extrudate of modified-rPET with and without heat stabilizer, were investigated the type of gel and the thermal behavior of the modified-rPET filament. From this preliminary experiment, it was found that the “unmelt-gel” defect was found from the modified-rPET filament, without the addition of Irganox®1010. On the other hand, the “crosslinked gel” defect was found from the modified-rPET filament, with the addition of Irganox®1010. Therefore, the addition of heat stabilizer (Irganox®1010) may cause the “crosslinked gel” significantly. Our future work, we will investigate the effect of another stabilizer and chain extenders on the gelation behavior, to complete this clarification systematically.