JURNAL MESIN TEKNOLOGI
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Material Selection for Fatigue Resistance in Coal Screening Systems: Finite Element Analysis of HB400 and GS20Mn5 at PT Bukit Asam Tarahan Port
Full text linkFatigue failure due to impact loads on the CV507 screen coal flow breaker plate has caused operational constraints that hamper coal production at PT. Bukit Asam – Tarahan Harbor. This research aims to determine the optimal material selection for coal flow breaker plates to achieve superior fatigue life and operational safety. HB400 material was selected for its high hardness and wear resistance, suitable for applications experiencing friction and direct coal impact. GS20Mn5 was chosen for its high toughness and superior impact energy absorption capabilities without cracking, particularly under repeated impact loading conditions. Two materials, Hardock (HB400) and GS20Mn5, with thicknesses of 15 mm and 20 mm respectively, were analyzed using static structural and explicit dynamic analysis in ANSYS Workbench 2022 R1 software. Simulation results indicate that the maximum operational impact load is 15.2 kN. The highest maximum Von Mises stress occurred in the Hardock (HB400) material with 15 mm thickness at 2348.3 MPa, with total deformation of 12.139 mm. Increasing thickness by 5 mm in the Hardock (HB400) material reduced stress and total deformation to 1543.3 MPa and 11.476 mm, respectively. GS20Mn5 material with 20 mm thickness demonstrated the longest fatigue life of 8 months compared to Hardock (HB400). This research provides material selection guidelines for coal flow breaker plates, offering significant value for engineering applications and the mining industry
The Influence of Cutting Methods and Feed Rate on Dimensional Accuracy and Surface Roughness of HMR Panel
Full text linkThis study investigates the influence of cutting methods and feed rates on the dimensional accuracy and surface roughness of HMR (High Moisture Resistance) panels. The aim is to determine the optimal cutting parameters that yield precise dimensions and smooth surfaces in CNC machining. Two cutting methods—single and double passes—were applied using feed rates of 2, 4, and 6 m/min. Dimensional accuracy was measured using a digital caliper, while surface roughness was evaluated with a surface tester. The results indicate that the double-pass cutting method significantly improves both dimensional accuracy and surface finish. Statistical analysis using ANOVA revealed that feed rate has a significant effect on surface roughness (p < 0.05), whereas dimensional accuracy is primarily influenced by the cutting method. These findings provide practical insights for optimizing CNC machining processes in furniture manufacturing using HMR panels
Performance Evaluation and Optimization of Chiller Systems: A Data-Driven Approach to Enhancing Energy Efficiency
Full text linkChiller systems account for a significant portion of energy consumption in industrial and commercial HVAC operations, often exceeding 50% of total power usage. However, inefficiencies such as elevated condenser pressure, inadequate heat transfer, and excessive compressor workload contribute to increased energy demand. This study presents a comprehensive performance evaluation of water-cooled centrifugal chiller systems based on 30 operational test scenarios. Key efficiency indicators—including Coefficient of Performance (COP), Specific Energy Consumption (SEC), and isentropic efficiency—were analyzed to identify performance gaps. The results revealed COP values ranging from 1.92 to 4.07, with an average between 2.8 and 3.2, indicating suboptimal performance relative to industry benchmarks (COP > 4). SEC values between 1.07 and 1.25 kW/ton further highlight opportunities for energy optimization. High condenser pressure (>7.5 barg) and negative subcooling (-4.1 K to 0 K) were identified as major contributors to inefficiency. The study emphasizes that optimizing water flow rates and maintaining proper heat exchanger conditions can significantly improve system performance. Unlike previous research relying on AI or IoT-based diagnostics, this work adopts a practical, data-driven approach, offering actionable insights for facility managers seeking to enhance energy efficiency and operational reliability
Analysis of The Vertical and Horizontal Type Cultivator Claw On The Performance Test of The Power Weeder Machine
Full text linkWeeds account for approximately 40–65% of rice production losses and affect 15–42% of arable land. If not managed promptly, crop yields could be drastically reduced. Traditional weed control methods, including manual weeding, chemical, semi-mechanical, and mechanical techniques, vary in effectiveness and efficiency. Conventional chemical and semi-mechanical methods are often less effective, costly, time-consuming, and environmentally detrimental. Thus, mechanical weed control presents a superior alternative. This study aims to compare the performance of power weeder machines equipped with vertical and horizontal cultivator claws in terms of weeding time, tool efficiency, and plant damage. The experiment was conducted on 30-day-old rice plants, with each test performed four times over a 1 x 6-meter area, maintaining a muck depth of 20 cm between rice plants. The power weeder machines were equipped with eight claws per unit, a 1.5 HP drive motor, and operated on a mix of oil and petrol fuel. Results indicate that the vertical-type cultivator claw achieved a work efficiency of 72.42%, while the horizontal-type cultivator claw achieved 86.04%. Weeding effectiveness was 93.10% for horizontal claws and 94.77% for vertical claws. Post-weeding, the horizontal cultivator claws caused 14.13% damage to rice plants, compared to 5.73% for vertical claws. Given its high weeding efficiency and minimal plant damage, the vertical type claw cultivator is highly recommended
The Effect of Variation in Electrode Type and Area on Electrical Productivity of MFC With Sago Stem Substrate
Full text linkMicrobial Fuel Cells (MFC) offer a promising solution for developing efficient and environmentally friendly alternative energy sources. MFCs convert chemical energy into electrical energy through anaerobic reactors equipped with anode and cathode electrodes containing substrates and microbes. This study investigates the effect of electrode type and area on the production of current, voltage, and power density using sago stem substrates in an MFC system enhanced with Lactobacillus plantarum. These bacteria play a critical role in facilitating electrolysis, thereby increasing electrical energy output. A dual-chamber MFC design was employed, testing electrode materials (copper, aluminum, nickel, and graphite carbon) and areas (30 cm², 40 cm², and 60 cm²). Measurements of current, voltage, and power density were taken over 36 hours. Results indicate that electrode area significantly influences voltage and current, while electrode type determines power density. The highest average power density, 432.953 mW/m², was achieved using nickel electrodes with a 30 cm² surface area. These findings underscore the importance of optimizing electrode properties to enhance the performance of MFCs
Utilization of Bagasse Waste Briquettes As An Alternative to Environmentally Friendly Technology
Full text linkBriquettes represent environmentally sustainable solid fuels that utilize renewable resources. This study aimed to assess the quality of bagasse waste briquettes as an alternative in eco-friendly technology. The experimental method was conducted internally at the PT SUCOFINDO Bengkulu laboratory. Briquettes were produced using varying compositions of bagasse waste: A1 (80 grams charcoal flour and 12 grams tapioca flour), A2 (30 grams charcoal flour and 6 grams tapioca flour), and A3 (20 grams charcoal flour and 5 grams tapioca flour). The production process involved preparation, drying, monitoring, grinding, adhesive mixing, molding, and final drying. Quantitative data analysis focused on key parameters including water content, ash content, and calorific value. Results indicated that the briquettes with 80% charcoal flour and 20% tapioca flour exhibited the highest calorific value at 6155 kcal/kg. It was concluded that all types of bagasse waste briquettes met Indonesian National Standards, demonstrating their potential as an alternative energy source through environmentally friendly briquette technology
Investigation of Drilling Parameters Affecting Borehole Circularity in Cortical Bone
Full text linkCortical bone drilling is a critical step performed prior to implant bolt placement, where drilling parameters play a significant role in the success of the procedure. This study investigates the effects of rotational speed, feed rate, and cooling fluid type on the outcome of the drilling process. A Box-Behnken experimental design was employed, involving 15 samples. Drilling operations were conducted using an SS316L drill bit on a 3-axis CNC machine. Circularity was analyzed using a Mitutoyo PJ3000 profile projector by measuring the x- and y-axis lines of the drill hole shadows under projector illumination. Hardness testing of bone specimens revealed an average microhardness of 45.48 HV with a standard deviation of 1.74, indicating their suitability as a human bone model. The lowest circularity value, 0.00125, was achieved at a rotational speed of 1,500 rpm, a feed rate of 60 mm/min, and in the absence of coolant. ANOVA results show that the feed rate (Vf) significantly affects circularity compared to rotational speed (V) and coolant, with a P-value of 0.0126 and an F-value of 8.86. These findings provide insights for optimizing cortical bone drilling procedures in biomedical applications. Future research should explore temperature distribution across the specimen and drill bit wear resistance resulting from the drilling process
Heat Transfer Analysis of Sandwich Plate System Application As Insulation Material for Fishing Vessels Hatches by Finite Element Method
Full text linkFish is a highly perishable food due to its suitability as a substrate for the growth of spoilage microbes, particularly bacteria. One method to maintain fish quality and extend its shelf life is preservation through a cooling system, where the duration of effective storage in the hatch is influenced by the quality of the insulation wall. Previous research modified the hatch insulation wall using a rice husk and white cement composition; however, these materials proved neither effective nor efficient in maintaining cooling temperatures. This study aims to determine the effect of heat transfer in a sandwich plate system on cooling time and temperature. Experiments were conducted using three variations in core layer thickness within a stainless steel-polyurethane-stainless steel configuration. The results indicated that at a temperature of 4°C, the maximum cooling times for each core layer thickness variation were as follows: variation 1 (3-20-3mm) lasted 62.5 hours, variation 2 (3-25-3mm) lasted 64 hours, and variation 3 (3-30-3mm) lasted 65.5 hours. The findings demonstrate that an increase in core layer thickness results in a prolonged maintenance of the cooling temperature within the hatch
Experimental Analysis of Climate Parameters Effect on Structural Steel Atmospheric Corrosion Rate in Medan City Environment
Full text linkThis study aims to explore the important role of weather parameters i.e. humidity, rainfall, temperature, and wind speed on the corrosion rate in the Medan City atmospheric environment. Three forms of material with low carbon steel type were prepared in this investigation. The exploration process was conducted for six months starting from June to December 2023, in the open area of the Engineering Faculty, Universitas Muhammadiyah Sumatera Utara. Corrosion rate assessment is carried out monthly using the weight loss method and climate parameter data is obtained from the Medan City Meteorology and Geophysics Agency (BMKG). The dimensions, initial preparation, data collection, post-test material preparation, and corrosion rate calculations refer to the ASTM G1 and G50 standards. Regression analysis and Pearson correlation explain the relationship between corrosion rate and climate parameters. The investigation showed that the corrosion rate fluctuated monthly from 0.1 to 0.5 mpy. By referring to corrosion resistance data on metal materials, it was found that the corrosion level was in the good resistance category "outstanding". Based on the regression analysis results, humidity, local temperature, and rainfall play an important role in the atmospheric corrosion rate in Medan City. The percentage of closeness between variables is ± 98% and the standard deviation is ± 0.0001. Further development is needed to determine other parameters that also play an important role in atmospheric corrosion rate and forming a random forest model for predicting future corrosion rates
The Effect of Sandblasting and Airless Spray Coating Mismatches on The Life of A Steel Building
Full text linkThe quality of construction is paramount in ensuring the longevity of steel buildings. A primary cause of reduced lifespan in steel structures is the development of corrosion. To mitigate high corrosion rates, careful consideration must be given to the steel fabrication process, particularly coating. This study employs Fishbone, 4M+1E, and 5W+1H cause-and-effect analysis methods to examine the impact of the coating process on the lifespan of steel building structures. By identifying the root causes of various problem factors, the study offers recommendations and proper implementations to address these issues. Discrepancies in the coating process were identified, and several recommendations were proposed based on the root cause analysis. The findings aim to ensure the estimated lifespan of the steel piperack building structure by preventing premature corrosion. The results indicate that coating defects predominantly stem from human factors, and several repair recommendations are provided based on these findings