Journal of Applied Materials and Technology
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Finite Element-Based Validation of Infill Wall Material Model for Seismic Response Analysis of Reinforced Concrete Frames
Get PDFMasonry infill walls are commonly used in reinforced concrete (RC) frame buildings for both architectural and environmental reasons. Although many consider RC systems to be non-structural, their interaction with surrounding frames can have a significant impact on their lateral stiffness, strength, and seismic performance. This can lead to stiffness issues and soft-story failures during earthquakes. This study looks at the structural function of masonry infills. It compares the experimental load-displacement backbone curve of an infilled RC frame with numerical predictions from four well-known Equivalent Diagonal Strut (EDS) models: Holmes, Mainstone, Liau and Kwan, and Paulay and Priestley. We looked at how well the models performed for both serviceability (initial stiffness) and ultimate limit states (peak lateral strength). The findings demonstrate a definite trade-off in predictive accuracy. With a mean stiffness ratio of 1.38, the Mainstone model yielded the most accurate estimate of elastic stiffness. The Holmes and Liau and Kwan models, on the other hand, significantly overestimated stiffness (ratio = 1.92). All models were conservative (ratios < 1.0) for peak strength. Holmes and Liau and Kwan produced the closest predictions (ratio = 0.84), while Mainstone was the most conservative (ratio = 0.80). These results indicate that the best choice of EDS model depends on the design goal: Mainstone is better for serviceability assessments, while Holmes and Liau and Kwan provide more realistic predictions for ultimate lateral capacity
From waste to value: Lapachol from teak wood waste as a green catalyst for sustainable soda cooking of Acacia and Eucalyptus
Get PDFThe development of a sustainable catalyst as an alternative to synthetic anthraquinone (AQ) is urgently needed for a more efficient pulping process. This study investigates the potency of lapachol, a natural naphthoquinone isolated from teak (Tectona grandis) wood waste, as a catalyst in soda cooking of three industrially important hardwoods: Acacia crassicarpa, Eucalyptus pellita, and Eucalyptus globulus. Approximately 97.7% purity of lapachol was isolated and applied at 0.09% (on oven-dry wood). For comparison, the commercial synthetic additive, 2-Methylanthraquinone (2-MAQ) was also used at the same dosage. Cooking experiments were conducted at 160°C under varying alkali dosages (23, 27, 31%) and times (4, 5, 6 h). The result revealed that the delignification performance was species-dependent: A. crassicarpa (S/V=0.74) was the hardest, while E. globulus (S/V=3.04) was the easiest to delignify. Notably, E. pellita (S/V=2.04) shows the greatest selectivity index. Lapachol shows the capability of enhancing delignification across the three wood species by decreasing the residual lignin by up to 5% in A. crassicarpa, 5% in E. Pellita, and 2% in E. globulus compared with soda cooking (control). Although the delignification is slightly lower than 2-MAQ, lapachol maintains pulp yields comparable to or higher than 2-MAQ. The selectivity index analysis confirmed that lapachol improved the balance between lignin removal and carbohydrate preservation, with the benefits most pronounced in E. globulus. These findings underscore lapachol as a promising sustainable pulping catalyst, offering the potential for impactful industry transformation through sustainable innovation
Fly ash adsorbent for ph improvement and manganese reduction in acid mine drainage
Get PDFMetal solid waste from coal combustion (fly ash) is abundant in Indonesia, as an effective and economical adsorbent in neutralizing acid mine drainage (AMD). Given that the continuous utilization of coal produces environmental challenges in the form of AMD containing acid residues and heavy metals such as manganese (Mn), an appropriate treatment solution is required. The adsorption method was chosen due to its simplicity, cost effectiveness, and ability to remove heavy metal pollutants. The purpose of this research is to characterize fly ash before and after heating by SEM and XRD analysis, and evaluate the effect of fly ash physical activation temperature by heating at 100oC and 200oC for an interval of 60 minutes on the characteristics and adsorption ability of fly ash. In addition, this study also evaluated the effectiveness of the adsorbent mass (fly ash before heating and after heating) in increasing pH and reducing Mn concentration in AMD so that it meets the quality standards of Class 1 river water. The results obtained from this study show a fundamental difference in the properties of fly ash before and after heating. Based on BET analysis, the physical activation process resulted in pore enlargement (0.196 nm) and increased surface area of the adsorbent (0.847 m2/g), which significantly affected its binding capacity to solutes (adsorption capacity). The application of fly ash as an adsorbent showed the ability to increase the pH value of acid mine drainage towards neutral conditions. The process of reducing heavy metal ions Mn by using 50 g of fly ash heating at 100oC and 200oC, resulted in a removal percentage of 94.74% and 98.44%. It is hoped that this research can provide innovative and sustainable AMD treatment and increase the use value of fly ash waste
Response surface methodology for glucose conversion by applying deep eutectic solvent (DES) as green solvent
Get PDFGlucose is a monosaccharide-type carbohydrate that serves as a fundamental building block of biomass. In this research, glucose was hydrolyzed using a Deep Eutectic Solvent (DES) as the solvent and AlCl3 as the catalyst. The effects of temperature and catalyst concentration were investigated as key variables in the reaction. The glucose conversion results were tested using the UV-Vis spectrophotometer. The yields of glucose conversion were analyzed using the Response Surface Methodology (RSM) with Design Expert Version 13 software. The results of RSM analysis show that glucose conversion increases linearly with rising reaction temperature. The effect of catalyst concentration indicates that glucose conversion decreases at higher catalyst levels. The reaction temperature and AlCl3 catalyst concentration that can be recommended for optimum conditions from the Design Expert data processing results are 112.869 C and 1.913% with a predicted conversion value of 93.844%
Antimicrobial properties of silver/graphene oxide nanocomposite prepared by redox chemical reaction
Get PDFSilver nanoparticles (AgNPs) exhibit outstanding antimicrobial properties, making them highly valuable in biomedical applications. This study presents the synthesis of a graphene oxide-silver nanoparticle (GO-Ag) nanocomposite via a redox chemical reaction, where the hydroxyl groups reduced silver ions present in graphene oxide (GO). Graphene oxide was obtained through electrochemical exfoliation of graphite, followed by ultrasonic exfoliation in the presence of silver ions to form GO-Ag. The materials were characterized using ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). UV-Vis, FTIR, and Raman spectra confirmed GO synthesis. In contrast, XRD and UV-Vis spectra verified the presence of silver nanoparticles in GO-Ag by detecting the surface plasmon resonance (SPR) band and silver’s characteristic diffraction peaks. SEM analysis showed the successful formation of silver nanoparticles on GO sheets. The disc diffusion method assessed Antimicrobial activity against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). GO-Ag nanocomposite displayed significant antibacterial activity, as evidenced by the formation of inhibition zones, whereas GO alone showed no antimicrobial effect. The enhanced antibacterial properties of GO-Ag are attributed to the synergistic interaction between GO and AgNPs. The increased surface area of silver nanoparticles further enhances their antibacterial effectiveness by facilitating better interaction with bacterial membranes. These findings highlight GO-Ag’s potential for use in antimicrobial coatings, wound dressings, and biomedical devices. This study demonstrates an effective, environmentally friendly approach to synthesizing antimicrobial nanocomposites, paving the way for their application in various medical and industrial fields
Properties of concrete containing crumb rubber and rice husk ash mixing with peat water
Get PDFThis study compares the effects of peat water and normal water as mixing and curing water on the properties of crumb rubber and rice husk ash concrete (CR-RHA). The number of crumb rubber and rice husk ash used on the concrete followed the optimum mixture from a previous study, which was 5% and 10%, respectively. The crumb rubber was treated to overcome the lack of adhesion by soaking it in water for 24 hours. Normal concrete (PCC) was also cast as a control. CR-RHA and PCC concrete were mixed and cured using normal and peat water. Compressive strength, tensile strength, and porosity were tested at 3, 7, 14, 28, and 56 days. In general, CR-RHA concrete and PCC concrete showed lower performance when mixed and cured with peat water compared to normal water. Peat water with high acidity decreased the calcium content and developed the amount of pores in concrete, resulting in strength reduction. However, due to the excess pozzolan from rice husk ash, CR-RHA concrete had better resistance as the strength loss was relatively smaller, respectively 11.4% at 28 days and 10.6% at 56 days. Furthermore, CR-RHA concrete showed lower porosity, higher compressive strength, and tensile strength than PCC concrete due to rice husk ash that improved concrete density by generating CSH and crumb rubber that prevented concrete from spalling in an acidic environment. It was also found that compared to the previous study, pre-treated crumb rubber exhibited better mechanical and durability of concrete
Powder metallurgy synthesis of Pd-doped MoS2: A structural and morphological study
Get PDFThis study reports the synthesis and structural characterization of palladium (Pd)-doped molybdenum disulfide (MoS?) produced via the powder metallurgy route. The primary objective was to investigate how Pd incorporation influences the structural, morphological, and electrical properties of MoS?, thereby demonstrating the advantages of powder metallurgy compared to conventional synthesis techniques. The materials were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy. XRD confirmed the retention of the hexagonal MoS? phase without the formation of secondary Pd-related phases, indicating successful substitutional doping. SEM–EDS analyses revealed a uniform Pd distribution and progressive morphological evolution with increasing Pd content, characterized by enhanced surface roughness and improved particle dispersion. FTIR and Raman spectra showed modifications in bonding environments and vibrational modes, evidencing the structural influence of Pd atoms on the MoS? lattice. Electrical measurements, performed using both I–V and four-point probe methods, demonstrated a conductivity increase from 9.6 × 10?? S·m?¹ for pure MoS? to 1.6 × 10?? S·m?¹ and 1.9 × 10?? S·m?¹ for the 1% and 2% Pd-doped samples, respectively. This enhancement is attributed to the higher charge carrier density and improved interlayer charge transport induced by Pd doping. These findings confirm that powder metallurgy provides an effective and scalable synthesis pathway for achieving homogeneous Pd incorporation in MoS?. The resulting materials exhibit excellent structural integrity and enhanced electrical performance, making them promising candidates for catalytic, sensing, and energy storage applications
Preparation and characterization of MoS2 thin films for thermoelectric applications using the PVD technique
Get PDFMolybdenum disulfide (MoS2) is a two-dimensional material with electronic and thermal properties that make it promising for thermoelectric applications. This research presents the results of synthesizing and characterizing MoS2 thin films obtained by Physical Vapor Deposition (PVD) on silicon dioxide (SiO2) substrates. Three experimental approaches were explored to assess how changes in deposition conditions affect the material quality. In the first trial, films were formed from commercial MoS? powder in a sulfur-rich (S2) atmosphere using a PVD tubular furnace. Next, water vapor (H2O) was added to the process to observe possible improvements in material formation. Finally, silver doping was investigated, introduced during deposition to examine structural and vibrational changes in the MoS2. The samples were characterized by Optical Microscopy (OM) and Scanning Electron Microscopy (SEM), as well as Energy Dispersive Spectroscopy (EDS), used to evaluate surface morphology and composition. X-ray Diffraction (XRD) was employed to identify the crystalline structure, while Raman Spectroscopy revealed the E2g1 and A1g vibrational modes, associated with the crystallinity of the material. The results indicated that the presence of H2O during deposition favored the growth of more ordered films, with more intense peaks in XRD and Raman spectra. On the other hand, silver doping caused vibrational changes that suggest modifications in the electronic structure of MoS2. These findings reinforce the material’s potential for use in thermoelectric devices and demonstrate that variations in synthesis conditions can significantly enhance its structural and functional properties
Web-Based System for Statistical Analysis and Thesis Progress Monitoring
Get PDFWeb-based monitoring systems serve as valuable tools in enhancing learning activities, particularly in the context of thesis supervision. Program heads and academic supervisors require timely, accurate information regarding students’ progress to guide academic outcomes effectively. This paper presents the development and implementation of an integrated web-based statistical and monitoring application tailored for thesis progress reporting. Built using the Laravel framework, the system incorporates statistical data visualization to enable students, supervisors, and administrators to interpret progress and communicate insights effectively. The system was developed using the prototype method, allowing iterative improvements based on user feedback. To ensure quality and functionality, the system was evaluated using the ISO/IEC 25010 quality model. A case study conducted in an electrical engineering department at a public university in Indonesia, involving students, academic supervisors, and administrative staff. The results demonstrate that the system not only improves oversight and coordination but also supports data-driven decision-making. By offering a clear, accessible overview of thesis progress, the application empowers all parties to take timely corrective actions, ultimately enhancing the overall educational experience
Assessing immobilization matrices for nuclear effluent treatment: Cs case study
Get PDFThe immobilization processes for nuclear waste have gained significant attention from the scientific community due to the growing global activity in the nuclear industry. Although these processes have been studied and applied since the mid-20th century, many questions remain that require further in-depth research, including the immobilization itself and the deposition of wasteforms in repositories designed to safeguard against future exposure. In this study, highly phase-pure zeolite A was synthesized via hydrothermal processing of coal fly ash from a Brazilian thermal power plant and loaded with Cs to evaluate thermal stability, structure, and immobilization in Nb-aluminoborosilicate and geopolymer matrices. Cs adsorption, confirmed by XRD peak intensity and Raman band changes, showed a 26 wt.% incorporation (INAA) after 24-hour sorption using simulated CsCl solution, a notable result given the fly ash impurities. The zeolite structure remained stable during the heating up to 960 °C, forming water-insoluble phases (pollucite and cesium aluminum oxide) right after structural collapse between 700 °C and 900 °C. Up to 40 wt.% of Cs-loaded waste was incorporated into a monolithic ceramic via thermal treatment of Nb-aluminoborosilicate glass and zeolite A at 900 °C for 2 hours, yielding a dense body (2.4 g/cm³) with low porosity (3.6%) and water absorption (1.63%). In contrast, raw Cs-loaded zeolite A showed high porosity (48%), water absorption (33%), and low density (1.44 g/cm³). Crystalline Cs phases formed at lower temperatures (900 °C) due to the devitrification nature of the glass. Geopolymer matrices immobilizing Cs-loaded zeolite exhibited water leachability comparable to similar materials, meeting nuclear waste disposal requirements