Mechanical Engineering for Society and Industry

Carboxymethyl cellulose films derived from pineapple waste: Fabrication and properties

Sun, 12 Jan 2025 14:41:56 +0000

Plastic waste poses a significant environmental challenge due to its non-biodegradable nature, emphasizing the need for sustainable alternatives like bioplastics from natural resources. This study develops and characterizes bioplastic films made from carboxymethyl cellulose (CMC) derived from bacterial cellulose synthesized using pineapple biowaste. Pineapple waste underwent fermentation to produce bacterial cellulose, which was chemically modified into CMC. Films were fabricated using CMC solutions with varying glycerol concentrations (0.5%, 1.0%, 1.5%, and 2.5% v/v). Characterization techniques, including SEM, XRD, FTIR, TGA, mechanical testing, and antibacterial assays, revealed that increasing glycerol concentrations smoothed the film's cross-sectional morphology, reduced crystallinity, and altered functional groups (e.g., new peaks at 870 cm⁻¹ and 935 cm⁻¹ attributed to C–H deformation). TGA indicated a four-stage thermal degradation pattern, with mass loss increasing from 77.2% to 88.4% at 2.5% glycerol, reflecting enhanced plasticization. Mechanical testing showed that the highest glycerol concentration increased film flexibility by 40.7 times while reducing tensile strength by 89.7%. Antibacterial activity against E. coli and S. aureus also improved with glycerol content. These results demonstrate the potential of CMC-based bioplastic films as sustainable packaging materials, offering customizable properties and promoting the value-added use of agricultural waste.

Design, fabrication, and performance testing of an energy storage and return (ESAR) foot prosthesis made of prepreg carbon composite

Tue, 14 Jan 2025 00:00:00 +0000

The high demand for prosthetics in Indonesia is not followed by the ability and quality of local production to fulfill the community's needs. There is a lack of comprehensive data regarding the specific challenges encountered by local prosthetic manufacturers in Indonesia, particularly in terms of technological limitations. This study aims to understand the effect of design parameters on the performance of the energy storage and return (ESAR) foot prosthesis prototype in normal walking activities for amputees. Three different designs were created according to commercial products, and a convergence test was conducted to ensure accurate results. Finite element method (FEM) analysis was used to determine the amount of deformation that occurred in each design made when applied with 824 N axial force. The ESAR foot prosthesis prototype made from carbon prepreg was fabricated using an out-of-autoclave method, and the mechanical testing was performed with a compressive test. The results indicated that the optimal design for the ESAR foot prosthesis determined by the decision matrix scoring criteria was Design 3. The final scores for Designs 1, 2, and 3 were 54, 53, and 77, respectively. Design 3 is the easiest to manufacture, has the slightest complexity, and the lightest mass, and undergoes the least deformation during simulation, although it is the least attractive. The study found a significant difference in displacement between the deflections obtained from simulation and experiment. This occurred because the prototype was found to have delamination, which decreased the load-bearing ability of the prototype during compressive testing. Compressive testing on the prototype yielded a deflection of 22.695 mm in heel strike and 18.065 mm in toe-off positions, while FEM analysis showed 16.377 mm and 3.912 mm. Therefore, strict quality control is essential, especially when using materials such as carbon prepreg, which are prone to delamination if not properly processed.

The effect of ignition timing on engine performance in a laser ignition engine: A CFD study

Wed, 15 Jan 2025 00:33:01 +0000

As a result of the high-power output, low fuel consumption, and low emissions expected from internal combustion engines, new engine technologies continue to be developed. Laser ignition systems are a solution to these expectations with the advantages they offer. Experimental and numerical studies related to laser ignition systems are accelerating today. In this study, an internal combustion engine was simulated with the spark and laser ignition systems, and the changes in engine performance for different ignition timings were investigated comparatively. ANSYS Fluent 2021 R1 software was used in the dynamic CFD study in which the entire engine cycle was analysed. Analyses were carried out at constant engine speed with an iso-octane+air mixture. Critical parameters such as pressure, volume, and temperature changes, power, torque, IMEP, MPRR, peak pressure, HRR, CHRR, start of combustion, and combustion duration were evaluated for both ignition systems. As a result of the study, optimum performance values were obtained at 680 °CA ignition timing with laser ignition system. At this ignition timing, power, torque, IMEP, MPRR, and peak pressure values were determined as 16.4302 kW, 62.7635 Nm, 14.1743 bar, 2.4665 bar/°CA, and 61.5611 bar, respectively. The laser ignition system increased engine performance, and smoother and knock-free combustion occurred. At optimum ignition timing, combustion duration was shortened, and in-cylinder temperatures decreased. The findings show that the laser ignition system will contribute to engine development studies by positively affecting engine and combustion performance.

Mechanical properties of biocomposite from polylactic acid and natural fiber and its application: A Review study

Mon, 03 Feb 2025 04:55:32 +0000

In the past decade, the development of biocomposite materials has attracted much attention due to the growing concerns about petroleum-based natural resource depletion and pollution. Among the various biocomposite materials, polylactic acid (PLA) is one of the most widely produced and ideal for use in commercial products. The manufacture of PLA biocomposites with natural fiber reinforcement as an alternative material that replaces synthetic materials is widely researched. The different types of natural fiber sources used in the incorporation of matrix and fibers are very important as they affect the mechanical properties of the biocomposites. In addition, PLA-based biocomposites can be produced by a wide variety of methods that can be found in various commercializations. This study aims to present the recent developments and studies carried out on the development of PLA-based natural fiber biocomposites over the past few years. This study discusses PLA biocomposite research related to their potential, mechanical properties, some manufacturing processes, applications, challenges, and prospects.

Effect of friction reducing devices on wellbore formation

Sun, 09 Mar 2025 00:00:00 +0000

Friction is one of the unavoidable factors during drilling. If not properly managed, it can significantly reduce the rate of penetration (ROP), especially in horizontal wells. This research aims to examine the effectiveness of the Friction Reduction Tool (FRT) in managing friction without causing damage to the formation. The FRT is designed to reduce friction between the drill string and the wellbore by minimizing contact. However, its performance is often influenced by two main factors: formation characteristics and drilling parameters. This study analyzes Well X-4, which was drilled without FRT, and Well X-5, which was drilled with FRT from a depth of 2837 m (MD). The analysis focuses on the tool’s impact on stick-slip issues, ROP, and mechanical specific energy (MSE). The results indicate that the use of FRT reduced stick-slip levels and MSE, enabling the drill bit to penetrate the formation more easily. Additionally, activating the FRT from the start increased the penetration rate by 18% compared to drilling without it. These findings suggest that the FRT effectively enhances the drilling rate while preserving the formation integrity.

Robust SVM optimization using PSO and ACO for accurate lithium-ion battery health monitoring

Sun, 09 Mar 2025 00:00:00 +0000

The increasing demand for reliable lithium-ion battery in various applications is focused on the need for accurate State of Health (SOH) predictions to prevent performance degradation and potential safety risks. Therefore, this research aimed to improve the accuracy of SOH prediction by integrating Particle Swarm Optimization (PSO) and Ant Colony Optimization (ACO) with Support Vector Machine (SVM) to overcome the overfitting problem in traditional machine learning models. The dataset used consisted of data from 1000 cycles of lithium-ion battery, collected under laboratory conditions. Data from lithium-ion battery cycles were analyzed using optimized PSO-SVM and ACO-SVM models. These models were evaluated using Mean Square Error (MSE) and Root Mean Square Error (RMSE) metrics, showing significant improvements in prediction accuracy and model generalization. The results showed that although both optimized models were superior to the baseline SVM, PSO-SVM had higher generalization performance during testing. The higher performance was due to the effective balance between exploring the search space and exploiting optimal solutions, making it more suitable for real-world applications. In comparison, ACO-SVM showed superior performance in training data accuracy but was more prone to overfitting, suggesting the potential for scenarios prioritizing high training accuracy. These results could be applied to extend the lifespan of lithium-ion battery, contributing to enhanced reliability and cost-effectiveness in applications.

Effect of windmill blade variations on the performance of piezoelectric energy harvesters: Enhancing vibration stability and power generation

Adhes Gamayel, Mohamad Zaenudin, Djoko Setyo Widodo — Sun, 09 Mar 2025 00:00:00 +0000

Piezoelectric energy harvesters (PEHs) are gaining attention for their ability to generate electrical energy from environmental vibrations, with applications in various industries. This study focuses on optimizing the performance of a PEH using a cantilever system driven by wind energy through the impact of windmill blades. The objective is to evaluate how the number of windmill blades affects the PEH's voltage output and vibration stability. Experiments were conducted in a wind tunnel with a 250 mm × 250 mm cross-section equipped with a 12-inch blower to generate airflow. Three windmill configurations—3 blades, 4 blades, and 5 blades—were analyzed for output voltage and deflection of two PVDF-based PEHs placed at a 30° angle. Results indicate that the 3-blade configuration produced the highest voltage (1.79V), 4% and 43% higher than the 4-blade (1.71V) and 5-blade (1.01V) configurations, respectively. This configuration also exhibited maximum deflection and lower frequency vibrations. Increasing blade count led to higher frequency vibrations but reduced deflection and voltage output. The study highlights that fewer blades result in greater deflection and better energy harvesting performance. These findings contribute to ongoing research in PEH systems, offering insights into optimizing energy harvesting from fluctuating wind conditions by balancing deflection amplitude and vibration frequency.

Evaluation of corrosion mitigation of SS904l using inhibitors with statistical and morphological analysis

Sun, 09 Mar 2025 00:00:00 +0000

This study evaluates the corrosion resistance of SS904L stainless steel, a highly alloyed material known for its exceptional performance in acidic environments, to address the need for optimized corrosion mitigation strategies. Corrosion inhibitors were utilized to enhance the material's durability, with the weight loss method employed to assess corrosion under varying conditions of temperature and pressure. Experiments tested inhibitor concentrations ranging from 0–5 mg per 100 mL over exposure durations of 24, 48, and 72 hours. Statistical analyses using ANOVA and regression confirmed a significant improvement in corrosion resistance with appropriate inhibitor concentrations. The Kesternich test provided comparative insights into the corrosion rate, validating the inhibitors' efficacy under simulated harsh conditions. Morphological analyses via X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) revealed the formation of protective layers on the metal surface, contributing to enhanced durability. These findings emphasize the critical role of corrosion inhibitors in extending the service life of SS904L and establish a relationship between inhibitor concentration, exposure time, and corrosion performance, paving the way for advanced corrosion mitigation strategies.

A Review on challenges and opportunities in wire arc additive manufacturing of aluminium alloys: Specific context of 7xxx series alloys

Dinesh Wasudeo Rathod — Sun, 09 Mar 2025 00:00:00 +0000

Wire arc additive manufacturing (WAAM) has emerged as a promising and cost-effective method for producing components made from aluminum alloys, particularly in industries like aviation and aerospace. This process enables the fabrication of high-performance parts while minimizing manufacturing complexities. The demand for aluminum 7xxx series alloys is significant in these sectors due to their outstanding material properties. Efficient production methods, such as WAAM, are essential for utilizing these high-demand materials effectively. Despite the advantages of the WAAM process, challenges remain, particularly when layer-by-layer deposition of Al 7xxx (Al-Zn-Mg) alloys is considered. The high heat density generated during the arcing process can lead to issues such as zinc evaporation, hydrogen formation, and oxidation of the alloys. Additionally, the WAAM technique faces hurdles like delamination, porosity, hot cracking, and complex thermal cycles, all of which can adversely affect the performance of the components produced. This study aims to tackle the challenges associated with the WAAM process by employing Gas Metal Arc Welding techniques, while also exploring opportunities for further research in this area.

Combustion characteristics of pyrolysis oil droplets from pyrolysis of polyethylene (PE) plastic waste

Dody Bimo Aji, Marwan Effendy, Ngafwan Ngafwan — Sun, 09 Mar 2025 00:00:00 +0000

Plastic waste is suspected to be a major contributor to environmental pollution, thus encouraging the need for innovative and effective management strategies to overcome it. Pyrolysis is considered an affordable way to process plastic waste, and even produce useful products in liquid form, which has the potential to be an alternative fuel in combustion engines. This study evaluated the combustion characteristics of pyrolysis oil derived from polyethylene (PE) plastic waste. The pyrolysis process was carried out under controlled conditions, at a furnace temperature of 250°C, a reactor temperature of 400°C, and a condenser temperature of 300°C, processing 1 kg of PE plastic waste. Temperature data was monitored every 10 minutes by installing several thermocouples. The pyrolysis process was able to produce 671 ml of liquid, which was later identified as plastic pyrolysis oil (PPO PE-11) and the rest in the form of residue reached 45 g. The results indicated that PPO PE-11 has a viscosity of 5.93 mm²/s, which is higher than diesel 3.8173 mm²/s. Meanwhile, its density is 0.779 kg/m³, which is slightly lower than diesel. The calorific value of PPO PE-11 is slightly higher than diesel, reaching 11,046.4 cal/g. The droplet scale combustion tests give a shorter ignition delay of 0.6 seconds at 41.28°C for PPO PE-11, compared to 1 second at 52.525°C for diesel, indicating its flammability.

Development of hybrid nanofluids and solar heat exchangers (SHX) to improve heat transfer performance in solar panel cooling

Sun, 09 Mar 2025 06:38:39 +0000

This study examined the thermohydraulic efficiency of a novel Solar Heat Exchanger (SHX) designed for cooling solar panels. The SHX was specifically created for 20 Wp solar panels measuring 450 × 350 mm. The cooling medium was a hybrid nanofluid (HNF) consisting of Al₂O₃ and SiO₂ nanoparticles (0.5–1%) suspended in a base fluid of ethylene glycol and water (EG/W) at a 10:90 ratio. Experiments were performed using flow rates ranging from 1 to 3 LPM. The HNF coolant demonstrated enhanced performance in the solar heat exchanger, with a maximum heat transfer rate increase of 56.07% compared with that of the base fluid. This improvement in the heat-transfer rate was associated with an increase in the heat-transfer coefficient, which was influenced by the flow rate and volume fraction of the HNF. The effectiveness of the HNF surpassed that of the base fluids by approximately 117%. The results indicated that higher flow rates and volume fractions improved cooling performance. The enhanced cooling efficiency and innovative SHX design make this study particularly relevant to the development of solar panel cooling systems, particularly those employing hybrid nanofluid coolants.

Temperature and material flow in one-step double-acting friction stir welding process of aluminum alloy: Modeling and experimental

Tue, 15 Apr 2025 17:21:26 +0000

Aluminum, known for its lower density compared to steel, is widely used in various applications. Welding is often required to form aluminum into technical structures. However, when fusion welding is used, it can lead to porosity in the weld. This occurs due to the significant difference in hydrogen gas solubility between liquid and solid aluminum, which traps hydrogen gas within the weld metal. Friction Stir Welding (FSW), a solid-state welding technique, has been proven to minimize porosity. However, for thick structures, FSW poses challenges, as welding must be done on both sides, increasing the welding time. To overcome this limitation, FSW has been modified into a one-step double-side FSW process, where two tools simultaneously work on both surfaces of the workpiece. This creates a unique condition with two heat sources and two stirring motion sources. To understand the temperature distribution and material flow in this process, modeling was conducted using Computational Fluid Dynamics (CFD). The upper and lower tools in the one-step double-side FSW process operate under identical conditions: a rotation speed of 1500 rpm, a welding speed of 30 mm/min, and a tilt angle of 0 degrees. The aluminum plate is treated as fluid, while the tools are considered solid in the model. The results of the temperature distribution modeling were validated against published studies, and the material flow was verified through macro- and microstructural observations of the cross-section. The validation showed that the model is accurate, with an error of only 4.07%.