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In rehandling activities In coal processing activities, mechanical tools such as crushers are needed to obtain production results in accordance with the company's desired targets according to the crusher target, therefore in processing it is necessary to carry out precise calculations, so that the ability of the tool (crusher) and know what things greatly affect the production processing process, so that it can be used optimally and has a high efficiency value for optimal production. Therefore, it is necessary to evaluate the results of the crusher production and the productivity of the support unit during rehandling activities in achieving the production target at ROM Port Area 2 in order to adjust the ability of the tool and other influencing factors with the crusher production target desired by the company. Actual rehandling productivity meets the crusher production plan target of 1100tph. Productivity in each zone with DT wheel 10, namely zone H there are 2 of 120,620 tph and 154,935 tph, zone L of 135,351 tph, zone M of 138,313 tph, zone I of 189,709 tph. And constraints on the crusher during a month that also affect obstacles in rehandling include schedule time with a total time of 176.72 hours, breakdown time with a total time of 4.84 hours, unscheduled time with a total time of 154.62 hours.

The implementation of coal mining activities with an open pit system at the end of its activities will leave behind the remains of former mining holes. Control of acid mine water is something that needs to be done during mining activities until the end of the mining process because acid mine water can cause a decrease in the quality of surface water and groundwater and have an impact on the survival of humans and biota that live on land and water. The initial characteristics of water using the floating treatment method of wetland, the pH, TSS, Fe, and Mn values ​​of ex-mining lake water do not meet the quality standards of the Government Regulation of the Republic of Indonesia Number 22 of 2021. The ability of water hyacinth plants to increase pH for 25 days is quite good with an initial pH value of 4.13 to 7.34. For 25 days, the TSS parameter of water hyacinth plants is also good at reducing TSS levels with an initial value of 6 mg/L to 3 mg/L, the Fe parameter of water hyacinth plants is also good at reducing iron levels with an initial value of 1.06 mg/L to 0.34 mg/L, while the Mn parameter of water hyacinth plants is quite good at reducing manganese levels with an initial value of 1.13 mg/L to 0.32 mg/L.

Organic waste management is an important issue in addressing environmental problems. One potential solution is bioconversion technology using Black Soldier Fly (BSF) maggots that can break down organic waste and produce larvae with economic value as animal feed. To increase the selling value and extend the shelf life, BSF larvae need to be dried using tools such as rotary dryers. This study aims to design and analyse the strength of a rotary dryer machine frame for maggot drying with a Finite Element Analysis (FEA) approach based on SolidWorks software. Simulations were carried out on several materials: ASTM A36, AISI 1020 Steel, and AISI 1045 Steel. The analysis results show that all materials are within safe limits based on Von Mises stress, deformation, and safety factor. AISI 1045 steel material gives the best performance with Von Mises stress of 14.238 MPa, deformation of 0.59 mm, and safety factor of 7.2. These results show that AISI 1045 steel is the most recommended material for the rotary dryer frame.

In mining activities, there is often a discrepancy between the plan and the actual conditions in the field, this discrepancy was found after reconciliation at the end of the progress (month). From the mining activities carried out by PT. Jembayan Muarabara (JMB), coal roof floor data was obtained from the survey which was then used to find survey tonnage, model tonnage data and actual tonnage scales. Then from this data it can be used to obtain coal recovery, coal looses in coal cleaning, loading, and coal transportation. The results of the study obtained tonnage data from the survey of 26,201.50 tons, a model of 26,488.50 tons and an actual tonnage of 24,885.09 tons. From the data obtained, the coal recovery value at the research location was 94.98% with coal losses in coal cleaning activities of 4.52% or 1196.39 tons and in loading activities of 0.5% or 120.02 tons with a tonnage discrepancy between planning and actual in the field of 1603.41 tons.

This study analyzes the morphological form and development characteristics of the Petrosea City Park green open space in Mimika Regency, Central Papua. Using qualitative descriptive-analytical methods, this research examines road patterns, spatial configurations, and architectural elements as well as the physical, economic, and socio-cultural characteristics of park development. The results show that the park implements a radial pattern centered on a roundabout with clear hierarchical zoning, integrating Kamoro cultural landmarks through bronze statues. However, infrastructure limitations and underutilized economic potential indicate the need for integrated development to optimize the function of green open spaces in the context of mining cities in Eastern Indonesia.

This study analyzes the impact of sustainable tourism concept implementation on the community of Tobati-Enggros Village, Jayapura City. Using qualitative descriptive methods with in-depth interviews, participatory observation, and document analysis involving 35 informants, this research evaluates three pillars of sustainability: economic, socio-cultural, and environmental aspects. The findings show that sustainable tourism implementation achieves a moderate effectiveness score of 2.7. Economically, tourism creates new employment opportunities and increases community income by 25%-400%, but benefits distribution remains unequal with 70% of profits controlled by 30% of residents. Socio-culturally, tourism helps preserve the unique "Women's Forest" tradition while causing erosion in traditional practices like gotong royong (community cooperation). Environmentally, significant ecosystem degradation occurs with water quality declining 56% and mangrove forest coverage reducing by 10%. The study recommends strengthening community-based tourism institutions, implementing comprehensive waste management systems, and developing community capacity building programs to optimize sustainable tourism benefits while preserving environmental and cultural integrity.

Land use conversion for vertical hospital development in urban areas represents a strategic response to increasing healthcare demands, particularly in regions with limited land availability. This study aims to analyze the impacts of land use conversion on vertical hospital development in Kelurahan Kota Baru, Abepura District, Jayapura City. The research employs qualitative descriptive methods with spatial analysis and field observations from 2015-2025. Results show significant land conversion from 3.16 hectares (2015) to 0.19 hectares (2025), with wetland areas (58.31%) being the most affected. The study reveals positive impacts including improved healthcare access and local economic growth, alongside negative impacts such as reduced green open spaces and environmental pressure. The findings contribute to sustainable urban planning strategies for healthcare infrastructure development in Papua.

Indonesia, which is located on the equator, has great potential to utilize solar energy, with an average solar radiation reaching 4.80 kWh/m² per day. This provides an advantage in the development of Solar Power Plants (SPP), one of which is through the installation of rooftop on the roof of the building as a source of electrical energy. This study aims to analyze the feasibility of SPP development by considering the techno-economic aspects of the Pondok Juice cafe. The total real electrical energy consumption required by the Pondok Juice cafe is 32,548 Wh/day. Assuming a system loss of 15%, the total electrical energy requirement that must be supplied by the SPP is 37,430.2 Wh/day. The initial investment projection is IDR 204,265,197, with operational and maintenance costs for 25 years of IDR 105,760,028. The investment feasibility analysis shows NPV of IDR 441,523,820.10, BCR 4.11, DPP ±5 years, and IRR 15.55%, which proves that this SPP planning is feasible to implement.

This study analyzes the use of safety harnesses in ensuring workplace safety at PT. XYZ, focusing on their role in preventing accidents during high-altitude work. The research employs the Job Safety Analysis (JSA) method to identify potential hazards and evaluate risk control measures. Data from 2021 to 2024 reveal a significant correlation workplace accidents with injuries ranging from minor to severe. The findings underscore the importance of strict adherence to safety regulations, proper training, and routine equipment inspections. The study concludes that consistent use of safety harnesses, aligned with national and industry standards, can significantly reduce accident rates and enhance worker safety.

International airports are complex work environments with unique occupational health and safety risks. As hubs of intensive transportation activities, airports involve various operations, including flight services, passenger handling, cargo management, and fuel operations. Early detection of fuel leaks is crucial to ensure the aircraft’s fuel system is free from leaks, blockages, or potential fire hazards. This study aims to analyze the causes of fuel leakage and identify appropriate mitigation measures, using observation and literature review methods. The findings indicate that fuel leakage occurring while the aircraft is parked suggests damage to certain fuel system components, such as seal gaskets, sealants, and dome nuts, which may suffer from wear or cracking due to age-related degradation. Such damage poses serious risks, including fire hazards, corrosion to aircraft structures—particularly in hard-to-reach areas like the wings or fuselage—and a drop in fuel pressure that could impair engine performance or cause flight cancellations. To address these issues, thorough inspections of all fuel system components are essential. Additionally, the use of sensors to detect abnormal changes in fuel pressure and flow, combined with rigorous leak testing after repairs, is recommended to ensure operational safety and reliability.

Fuel consumption is a necessity in moving mechanical equipment, where fuel consumption is influenced by road conditions, horsepower, and load factors. PT. Mitra Indah Lestari uses Hyundai 480 and Sany750-H excavators. The transport equipment used is Wechai WT90, Tonly TLD90, and Quester CWE 330. This study uses a quantitative method and obtains fuel consumption results, where the fuel consumption of the Hyundai 480 and Sany 750-H excavators is 37.89 liters/hour and 59.91 liters/hour, respectively. The fuel consumption of the Wechai WT90, Tonly TLD90, and Quester CWE 330 transport equipment is 25.19 liters/hour; 27.53 liters/hour; and 10.66 liters/hour, respectively.

This study aims to analyze the aircraft maintenance procedures following a bird strike incident on Engine #1, focusing on incident identification, maintenance actions taken, damage evaluation, follow-up recommendations, and compliance with aviation industry standards. Data for the study were obtained through official technical documentation such as the Technical Standard Manual (TSM) and Aircraft Maintenance Manual (AMM). Data analysis was conducted using the Miles & Huberman method, which includes stages of data collection, data reduction, data presentation, and conclusion drawing. Data validity was ensured through source triangulation, relying on various related documents to strengthen the findings. The results showed that the maintenance procedures applied were in accordance with international standards. Post-incident maintenance was carried out systematically and well-documented, with no procedural violations or technical neglect. The damage evaluation of Engine #1 revealed that the corrective actions implemented were effective, ensuring the aircraft's safe return to service. Recommendations for further maintenance include enhancing supervision of existing procedures. Overall, the post-incident maintenance met best practices in the civil aviation industry, ensuring aircraft safety and reliability.

The large number of cattle breeders in Indonesia has positive and negative values. Cattle farmers generally produce livestock waste such as cow rumen. Cow rumen can be used as a starter for alternative biogas energy production, and cabbage vegetable waste has the potential to be used as raw material for making biogas, because it contains nutrients such as crude protein (PK) 22.47%, crude fat (LK) 3.05%, crude fiber (SK) 12.09%, dry matter 10.22% and extract material without nitrogen 34.96%. Apart from that, in this research cow rumen and EM4 were also used as starters for the anaerobic fermentation process. The cow's rumen contains methane bacteria, namely Methanosarcina sp, and the cow's rumen also contains quite high levels of organic compounds with a COD value of 17,183 mg/l. Effective Microorganisms (EM4) are bacteria whose function is to accelerate the degradation process of organic materials. The aim of this research is to design a biodigester, and carry out biodigester design trials. The research methods carried out are COD analysis, CH4 analysis and pH analysis. The results showed that the percentage of CH4 increased in a mixture of 100% cow rumen, because the total COD value in the substrate was directly proportional to the addition of the cow rumen composition. This can be seen from the total COD in 100% beef rumen starter of 1175 ppm.  

Eco riding/driving is an approach to driving that aims to optimize fuel efficiency and reduce environmental impact. This technique guides drivers to avoid sudden acceleration and braking in order to maintain a stable speed, maintain optimal tire pressure and carry out regular vehicle maintenance. This technique helps save fuel, reduces greenhouse gas emissions, and extends vehicle life. The aim of this research is to determine the level of understanding of students in the automotive engineering education study program regarding Eco Riding. This research is a survey research carried out from July - December 2024 to 56 students in the automotive engineering education study program at Muhammdiyah University, Purworejo. The research data were analyzed using quantitative descriptive analysis. The research results showed that the level of students' understanding of Eco Riding was in the high category at 50%, followed by the medium category (32.1%), rendang category (14.3%) and very high category at 3.6%.

Compensation is an effort to reduce the pollution load from other sectors to replace the wastewater load that will be discharged by businesses and/or activities due to river water quality being exceeded. Currently, most large rivers in Indonesia have exceeded the water quality standards set by the government. The one of the hospitals in Jember plans to discharge wastewater into the Bedadung River. However, the Biochemical Oxygen Demand (BOD) quality standard for the Bedadung River has been exceeded. Therefore, alternative compensation activities are needed to reduce the BOD levels of the Bedadung River. Bathing, Washing, and Toilet (MCK) facilities with biofilter septic tanks were chosen. This technology is considered to be able to effectively reduce the BOD concentration of domestic waste before being discharged into the environment. This study aims to calculate the potential for reducing the BOD pollutant load in Bedadung River water if compensation is carried out through the construction of MCK with a biofilter septic tank system, so that it is expected to provide a significant contribution to improving river water quality while supporting the sustainability of hospital activities.

Using a descriptive method with a triangulation approach including observation, document analysis, and interviews this study ensures data reliability. Daily monitoring is conducted on wastewater flow and pH levels, while monthly laboratory analysis covers eight key parameters: Total Suspended Solids (TSS), iron (Fe), copper (Cu), zinc (Zn), total chromium (Cr), phosphate (PO³), oil and grease, and pH to evaluate the perfomance of the treatment system. The treatment process begins with the inflow of 960 m³ of wastewater per day into the storage pond, where aeration is applied to ensure homogenization before being transferred to the neutralization unit. pH adjustment is carried out by adding NaOH or HCl before the wastewater undergoes coagulation and flocculation stages. The study’s findings indicate that the WWTP meets the environmental quality standards established in accordance with the Decree of the Head of the Investment Coordinating Board of the Republic of Indonesia (2020), Number SK.214/1/KLHK/2020 concerning the Permit for Wastewater Disposal into the Sea on Behalf of PT Pembangkit Jawa Bali Unit Pembangkitan Gresik. This study emphasizes the importance of systematic monitoring and treatment in wastewater management.

This study aims to evaluate the performance of the Sewage Treatment Plant (STP) at PT PLN Nusantara Power Unit Pembangkitan Gresik in reducing pollutant loads from domestic wastewater. The evaluation involves analyzing water quality parameters including pH, BOD, COD, TSS, oil and grease, total ammonia, and total coliform at both inlet and outlet of the STP. Additionally, the actual daily discharge was observed and compared to the design capacity to assess operational efficiency. The method used was descriptive qualitative, involving field observation, documentation, and laboratory test data analysis during the January–March 2025 period. The results show that all outlet parameters met the effluent standards set by Regulation No. 68/2016 of the Ministry of Environment and Forestry. However, the actual flow rate, which is only 1.6–3.3% of the design capacity, indicates potential inefficiencies in energy use and biological processes. Therefore, operational adjustments and optimization of STP capacity utilization are necessary for more efficient and sustainable system performance.

Handling natural disaster victims requires a fast, precise, and fair aid distribution process. In this context, expert systems can be utilized as a decision-making tool in determining the type and amount of aid that should be given to victims. This article develops a desktop-based expert system using the Java programming language, which is able to calculate the type of aid based on the condition of the victim, the level of damage, and the number of affected family members. The method used is a rule-based expert system with if-then logic. The results show that this system can assist field officers in accelerating the calculation and distribution of aid.

The cooling system on the Jupiter MX 135 CC motorcycle functions to maintain a stable engine temperature to prevent overheating. There are two main types of cooling systems on motorcycles: Air Cooling System and Liquid Cooling System. In the Air Cooling System, the working principle involves heat generated by the motorcycle engine being dissipated through cooling fins located around the engine block. Air that flows through the fan or moves as the motorcycle runs will carry away the heat. Meanwhile, in the Liquid Cooling System, the working principle involves coolant (usually a mixture of water and antifreeze) flowing through channels inside the engine to absorb heat. The coolant is then carried to the radiator, where the heat is transferred to the air with the help of a fan. Common problems that occur in the cooling system of the Jupiter MX 135 CC motorcycle can interfere with engine performance and risk causing serious damage if not addressed promptly. Some of the common issues include, Low coolant level, Radiator damage, Water pump failure, Malfunctioning thermostat (thermostat stuck), Leaking or broken radiator hose, Radiator fan malfunction, Dirty or contaminated coolant, Ineffective fan (for air-cooled engines), Overheating due to excessive load. The objectives of this study are to understand how the cooling system on the Jupiter MX 135 CC motorcycle works, to identify damages occurring in the cooling system, and to solve the issue of water pump leakage in the cooling system. The methods used in this research include observation, literature study, interviews, and action methods. The results of problem identification in the cooling system of the Jupiter MX 135 CC motorcycle show, The water jacket gasket is corroded ,The bearing on the water pump is damaged, The water pump impeller is worn out, The radiator pump seal has hardened, causing a squeaking sound around the water pump, Solutions to the problems in the cooling system components include replacing the damaged and worn parts (head gasket, bearing, seal, and impeller) and refilling with new coolant.

This study aims to examine the effect of varying the length of oil palm empty fruit bunch (EFB) fibers on the mechanical properties and macrostructure of Palmfiber Reinforced Concrete (PRC) as an alternative to Glassfiber Reinforced Concrete (GRC). EFB fibers were selected due to their abundance, eco-friendliness, and potential to enhance the mechanical properties of lightweight concrete. The methods employed include flexural testing and macrostructural observation using five fiber length variations (3 cm, 4 cm, 5 cm, 6 cm, and 7 cm). The results show that a fiber length of 5 cm produced the highest flexural stress of 11.78 kg/cm², while a length of 4 cm yielded the highest modulus of elasticity at 162.2 kg/cm². Macrostructural observations revealed good bonding between fibers and matrix in most specimens, although performance differences were observed due to fiber distribution and manual compaction processes. In conclusion, fiber length affects the mechanical performance of PRC, yet production process optimization is necessary to achieve more consistent results.