Applied Mechanics and Materials Vol. 933

Abstract: By compounding all of its components through extrusion and injection moulding, chemically functionalized high-density polyethylene (CF-HDPE) hybrid composites reinforced with oil palm empty fruit bunch (OPEBF) and nettle (NETLF) fibers have been developed by the Palsule process. H1, H2 and H3 hybrid composites of (OPEBF/NETLF)/CF-HDPE have been developed with increasing OPEBF but fix total amounts of 30% of both OPEBF and NETLF. The thermal stability of all these H1, H2 and H3 hybrid composites increases with increasing OPEBF and decreasing NETLF in them. The overall thermal stability of H1, H2 and H3 hybrid composites is between their CF-HDPE matrix and the reinforcing OPEBF and NTELF reinforcing fibers. These composites show thermal stability till 245^°C, after releasing their volatile matters and moisture.

Abstract: Solid acid catalysts offer several advantages over liquid acids, primarily in terms of environmental friendliness, ease of separation, and reusability. They have enhanced selectivity and catalytic activity. They are particularly useful in industrial processes where corrosive liquid acids pose handling and waste disposal challenges. Potential solid acid catalysts can be prepared by the modification of naturally occurring clay samples like kaolinite, bentonite, etc. A new, economically and environmentally benign solid acid catalyst for the esterification of cyclohexanol with glacial acetic acid has been prepared from bentonite by mixing with carbon nanodots (CND) prepared from different sources. The carbon sources used for the preparation of CND are glucose, watermelon peel, lemon peel and sucrose. The samples were characterized by acidity measurements and X-ray diffraction (XRD). The XRD pattern of the sample showed that both the components (carbon nanodots and bentonite) are present in the Clay-CND composite. Clay-CND composites showed greater acidity and activity than the pure clay sample. The results showed that the greater the amount of carbon nanodots in the clay-CND composite greater the activity and acidity. Acidity and catalytic activity are correlated. The sample B-SCND, in which CND was prepared from sucrose, showed maximum percentage conversion and acidity.

Abstract: Procion M dyes are widely used reactive dyes for cellulose-based textiles due to their bright colors, fastness properties, and covalent bonding capabilities. This study examines the chemical structure of Procion M dyes, highlighting key components: the chromophore, reactive group, solubilizing group, and linking group. The hydrolysis and alcoholysis of these dyes were investigated using Procion Red M-X5B and Procion Blue M-XG under various temperatures (25°C, 35°C, 45°C). Experimental setups included UV-Vis and IR spectroscopy to monitor dye concentration and functional group changes, respectively. Data revealed temperature-dependent reaction rates, with higher temperatures accelerating both hydrolysis and alcoholysis. Thermodynamic analysis showed that both processes are exothermic and spontaneous, with enthalpy changes of -20 kJ/mol (hydrolysis) and -25 kJ/mol (alcoholysis), and Gibbs free energy changes confirming spontaneity. FTIR and HPLC analyses provided insights into molecular structural changes and product formation. These results underscore the efficiency and temperature sensitivity of Procion M dye reactions, offering valuable information for optimizing textile dyeing processes.

Abstract: The present study explores the green conflation of manganese dioxide (MnO₂) nanoparticles through a simple, Eco-friendly, and cost-effective system. This conflation process involves the response of potassium permanganate with an waterless splint excerpt of Hibiscus rosa- sinensis, serving as both a reducing and stabilizing agent. The green conflation system is profitable as it avoids poisonous chemicals, making it safer for both the terrain and implicit operations. The synthesized MnO₂ nanoparticles were considerably characterized using colorful logical ways. X-ray diffraction (XRD) analysis was used to confirm the liquid structure, while Fourier- transfigure infrared (FT- IR) spectroscopy handed sapience into the functional groups present in the material. UV-Visible spectroscopy was employed to study the optic parcels and band gap of the synthesized nanoparticles. Morphological details were observed through Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), which revealed the nanoparticles in globular shape and nanoscale size. One of the notable findings of this study is the photocatalytic effectiveness of the synthesized MnO₂ nanoparticles. Under visible light irradiation, these nanoparticles effectively degraded methyl orange color in waterless results, showcasing their eventuality as an effective photocatalyst. also, the synthesized MnO₂ nanoparticles demonstrated promising operations in the junking of organic adulterants from water, emphasizing their environmental significance. Overall, this study contributes to the development of sustainable nanomaterials for environmental remediation, particularly for wastewater treatment operations. The green conflation approach, combined with the excellent catalytic parcels of MnO₂ nanoparticles, underscores the material's eventuality for practical and large- scale operations.

Abstract: This paper explores the photocatalytic degradation of methyl orange (MO) dye using Mg doped ZnS nanoparticles, synthesized through a microwave assisted solvothermal method using zinc acetate, magnesium chloride, and thioacetamide. The x-ray diffraction (XRD) analysis confirmed the crystalline structure of the synthesized nanoparticles, indicating their suitability for photocatalytic applications. The optical absorption spectra revealed characteristic peaks in the UV-visible range, correlating with the nanoparticle’s effective light absorption capabilities. Furthermore, the energy bandgap, determined through Tauc plots, highlighted the material's potential for visible light induced photocatalysis, making it an efficient catalyst for dye degradation. Furthermore, the experiment involved preparing an aqueous MO solution, mixing it with Mg doped ZnS nanoparticles, and exposing it to visible light. The changes in the dye were observed using UV-Visible spectroscopy. This method showed that the nanoparticles effectively helped in degrading the dye up to 78.5%. The results indicate that Mg doped ZnS nanoparticles are effective for wastewater treatment, as they can effectively break down harmful dyes and can reduce environmental hazards, providing a sustainable and efficient method to treat industrial wastewater and ensure that released water is safer for the environment.

Abstract: Effective condition monitoring is crucial for maintaining industrial rotating machinery. This study investigates a predictive maintenance approach to diagnose and resolve excessive vibration in a refinery’s centrifugal pump. Vibration analysis using Fast Fourier Transform (FFT) and phase difference diagnostics identified a dynamic imbalance caused by contaminant accumulation on the impeller, resulting in vibration spikes of 11.61 mm/s with a dominant FFT spectrum at 1X RPM. To mitigate this issue, dynamic balancing was performed in accordance with ISO 1925 and ISO 1940-1 standards, successfully reducing the vibration to 3.59 mm/s. The results validate vibration-based diagnostics as a proactive maintenance tool, minimizing downtime and improving reliability. This study demonstrates how predictive maintenance strategies can enhance the performance of rotating machinery, with potential applications in other industrial systems.

Abstract: Cavitation is a critical issue in centrifugal pumps, leading to severe mechanical wear, reduced efficiency, and potential system failure. This study investigates cavitation in a centrifugal pump operating in a Hydrocracking Complex (HCC) using vibration analysis combined with Fast Fourier Transform (FFT) spectral diagnostics. The results reveal characteristic cavitation signatures, including Blade Pass Frequency (BPF) peaks, 1X RPM harmonics, and high-frequency random vibrations exceeding 120k CPM, with overall amplitudes ranging from 5.53 to 9.17 mm/s. Despite component replacement, vibration levels remained elevated, indicating that persistent low-flow conditions, suction-side pressure fluctuations, and deviation from the Best Efficiency Point (BEP) were the root causes of cavitation. The findings demonstrate that vibration spectrum analysis provides a quantitative and reliable tool for diagnosing cavitation severity under real industrial conditions. Unlike many laboratory-based studies, this work contributes an industrial case study from a hydrocracking unit, offering practical insights into predictive maintenance strategies for large-scale pumping systems.

Abstract: Strength and remaining life of a storage tank was evaluated based on API 650/653 standard code. The tank was a vertical-cylindrical tank with a diameter of 29 meters and maximum capacity of 4,719 m³. The actual thickness of the shells of the tank were measured using ultrasonic testing. The finite element code ANSYS Workbench 2023 was used to perform the static stress analysis of the 3D model of the tank. The results show that the maximum equivalent stress was within the allowable stress of the material, hence the tank was considered safe based on API 650. The remaining life of the tank was then evaluated based on API 653. The critical section was found in the 2^nd course of the tank shell with a remaining life of 22.5 years.

Abstract: When the EV era begins, it is predicted that many ex-ICE vehicles will no longer be allowed to be used. Unless the vehicles are converted into EVs. In this study, a 1500 cc class MPV is converted into an EV with a 10 kW’s motor. The manual transmission is still used. It begins with analyzing the vehicle's power needs and determining the specifications of the devices used. The power is transmitted through the gearbox via an adapter. Designing the adapter is an effort in itself, followed by a strength analysis using the FEM. The conversion was successfully carried out, and the vehicle could run well, with the electrical components functioning without errors. The hypothesis is that the vehicle can reach speeds up to 100 km/h with a range of 100 km on a single charge. The optimization can be continued by directly coupling the motor to the differential.