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Acid mine drainage (AMD) is characterized by low pH and high concentrations of heavy metals such as iron (Fe) and manganese (Mn) that exceed environmental quality standards, thus requiring effective treatment to prevent environmental pollution. This study aims to evaluate the ability of a mixture of activated carbon derived from pineapple leaves mixed with coal to increase pH and reduce Fe, Mn, and Total Suspended Solids (TSS) levels in acid mine drainage at PT Alreksa Bara Mitra. The process to make activated carbon involved preparation, carbonization, and activation processes on the pineapple leaves and coal separately. The following step is to mix but pineapple leaves and coal the has been activated. The treatment was conducted using an adsorption method with variations in adsorbent mass of 4 g, 8 g, and 12 g and a contact time of 30 minutes. The parameters analyzed included pH, Fe, Mn, and TSS before and after treatment, and the results were compared with the quality standards stipulated in Minister of Environment and Forestry Regulation No. 05/2022. The results showed that the characteristics of the activated carbon mixture met the SNI 06-3730-1995 standard. Increasing the adsorbent mass contributed to the rise in pH from 5.5 to near the acceptable range of 6–9 and significantly reduced Fe, Mn, and TSS concentrations below the permitted limits.The findings indicate that the mixture of pineapple leaf- and coal-based activated carbon is an effective, economical, and environmentally friendly alternative adsorbent for acid mine drainage treatment.

Sanitation is an important aspect in the fish feed industry to ensure product quality, product safety, and employee health. PT. CentralPertiwi Bahari is a fish feed industry that has implemented sanitation as part of its product quality assurance system. This study aims to examine the implementation of sanitation at PT. CentralPertiwi Bahari to obtain an overview of the implementation of sanitation based on Permenkes No. 70 of 2016. This study uses a qualitative descriptive method carried out in January-February 2025. Data collection was carried out through observation, interviews, document reviews and scientific literature. Aspects studied include external environmental sanitation, factory environmental sanitation, building sanitation, production process sanitation, raw material sanitation, and employee sanitation. The results of the study indicate that PT. CentralPertiwi Bahari has implemented sanitation in accordance with the provisions of Permenkes No. 70 of 2016 as indicated by clean environmental and building conditions, the availability of good sanitation facilities, proper management of raw materials, and employee sanitation that is consistently implemented. The implementation of sanitation at PT. CentralPertiwi Bahari has supported efforts to maintain quality and occupational health. However, conditions requiring attention, such as water pooling outside the factory during rainy seasons, require remedial measures to optimize sanitation implementation. The results of this study are expected to serve as a basis for company evaluation and a reference for similar industries in improving sustainable sanitation practices.

The problem with a passenger car with a capacity of 15 people lies in its unscheduled maintenance and having broken down on the road. The purpose of component replacement planning is to obtain component replacement costs, maintenance and repair schedules for the 2026 period, and the maintenance cost-to-profit ratio. The planning method includes collecting previous maintenance data, applying the inspection-replace-repair-overhaul (IRRO) method, evaluating component conditions, estimating component lifespan, estimating labor costs, estimating supporting equipment to be used in maintenance, estimating the time to replace spare parts or reinstall repaired components, estimating maintenance and repair costs for the 2026 period, and calculating the maintenance cost-to-profit ratio. The results of component replacement planning obtained costs for the 2026 period are IDR 11,780,000 with an estimated passenger car rental rate of IDR 800,000/24 ​​hours (day) which has the potential to be rented for 4,320 hours/year, and the ratio of maintenance costs to profits is 10.33% which implies that passenger cars with a capacity of 15 people are still prospective to generate profits and are suitable for use for the next few years.

This study aims to design and develop an electrical installation panel by applying engineering safety principles in the water spray booth of a vehicle body painting system. Field observations indicate that electrical panels in painting rooms often do not meet safety standards, which can lead to short circuits and potential fire hazards. The research employed a Research and Development (R&D) method using a simplified Borg and Gall model consisting of nine stages, starting from problem identification to effectiveness testing. Expert validation results obtained a score of 87.5% (highly valid), practicality testing yielded 90% (very practical), and effectiveness tests showed an average current of 4.1 A, with both the MCB and emergency stop functioning optimally. The developed panel product is declared feasible to be used as a practical learning media for automotive electrical systems. Based on the test results, the panel product was declared suitable for use and can be used as a learning medium in automotive electrical practice, helping to increase understanding of the application of safety in electrical installations in the automotive industry.

Unexpected downtime of a 2 kg/hour coffee grinder is crucial in cafe operations, thus less guaranteeing the availability of the grinder. The purpose of component replacement and repair planning is to obtain a prediction of the maintenance and repair schedule and costs in the 2026 period. The component replacement planning method includes collecting previous maintenance and repair data, applying the inspection-replace-repair-overhaul (IRRO) method, assessing component conditions, predicting component life, predicting technician costs, predicting supporting work equipment and supporting materials to be used in maintenance, predicting the time to replace spare parts or reinstall components after repair, estimating maintenance and repair costs for the 2026 period, and calculating the ratio of maintenance costs to profits. The results of component replacement and repair planning obtained maintenance costs for the 2026 period are IDR 2,350,000, - with an estimated coffee grinder rental rate of IDR 25,000/hour which has the potential to be rented for 1440 hours/year, and the ratio of maintenance costs to profits is 6.5% which implies that the coffee grinder with a capacity of 2 kg / hour is still suitable for use for the next few years and still has the opportunity to make a profit.

Traffic performance on urban road segments is strongly affected by vehicle volume and travel time, particularly during peak periods. This study analyzes the relationship between travel duration and the total number of vehicles passing along Otto Iskandar Road as an illustration of urban traffic conditions. Data were collected through field surveys, focusing on two main variables: average vehicle travel time and total traffic volume. Statistical analysis was performed using IBM SPSS Statistics, including normality testing and the Wilcoxon Signed Rank Test to identify potential differences between the observed variables. The results show a difference in average values between travel duration and vehicle volume; however, this difference is not statistically significant at the 95% confidence level (p = 0.180). These findings indicate that increases in traffic volume do not always lead to proportional increases in travel time, although they can still influence the stability and efficiency of traffic flow. The results are consistent with previous studies, such as Halim (2021), who reported that U-turn movements affect speed and traffic performance, and Handayani et al. (2024), who found that parking activities and vehicle maneuvers reduce road capacity. Other studies also highlight the impact of side friction and traffic flow variations on speed and saturation levels. Overall, this study emphasizes the importance of managing vehicle flow and monitoring travel time in urban transportation planning and traffic management.

This study focuses on the analysis of traffic density in Jember City, particularly at the Wirolegi Intersection, which is known to have a high density level. This condition often triggers congestion that hinders public mobility, so that appropriate and data-based handling efforts are needed. The purpose of this study is to identify and analyze the level of density at critical congestion points through a statistical approach using the One Way ANOVA method. The research method used is quantitative descriptive with a descriptive observational approach. Primary data was collected directly through a field survey in 2025 at the Wirolegi Intersection as one of 3 intersections in Jember City. The data obtained were then processed using normality tests, homogeneity tests, and One Way ANOVA with the help of SPSS software. The results of the analysis show that the traffic flow density on the three routes studied, namely Jalan Gunung Haryono, Jalan Brigjen Katamso, Jalan Yos Sudarso, does not show a significant difference. The significance value of the ANOVA test is greater than 0.05 which indicates the similarity of density levels between routes. Further testing (post hoc testing) also strengthens this finding. The conclusion of this study shows that handling congestion at the Wirolegi Intersection needs to be done comprehensively through traffic control and evaluation of the transportation system to improve smoothness and mobility in Jember City.

This study aims to evaluate the effectiveness of various doses of 6.25% Poly Aluminium Chloride (PAC) and 0.1% polymer flocculant in reducing Total Suspended Solids (TSS) and assessing pH changes in coal stockpile wastewater at PT PLN Nusantara Power UP Paiton Unit 9. Stockpile wastewater typically contains high levels of suspended solids originating from water spray activities that carry fine coal particles. The coagulation–flocculation process was performed using the jar test method with PAC dosages of 35 ppm, 50 ppm, and 65 ppm, along with flocculant dosages of 6 ppm and 7 ppm. pH and TSS were analyzed before and after treatment to assess process effectiveness. The results indicate that a PAC dosage of 35 ppm combined with a 6 ppm flocculant achieved the highest TSS removal efficiency of 98.15%. Increasing PAC dosage resulted in reduced performance due to overdosing effects, leading to charge destabilization and impaired floc formation. These findings highlight the importance of optimizing coagulant dosage to improve stockpile wastewater quality for safe reuse in operational activities.

Increasing in energy demand and limited fossil fuel reserves have driven the use of environmentally friendly alternative energy sources. This study aims to analyze the effect of pyrolysis temperature variations on the quality of biopellets made from bagasse and coffee husks. The materials were prepared in a 50:50 ratio with the addition of 15% tapioca flour as a binder. The pyrolysis process was carried out at temperatures of 450°C, 500°C, and 550°C for 120 minutes in oxygen-free conditions. The biochar resulting from pyrolysis was formed into biopellets, which were then tested for proximate composition, calorific value, and combustion rate. The results showed that an increase in pyrolysis temperature had a significant effect on the characteristics of the biopellets. A temperature of 550°C produced the lowest moisture content (8.436%), the highest fixed carbon content (62.191%), the highest calorific value (6293 cal/g), and the highest combustion rate (0.05789 g/sec). Conversely, ash content increased with rising temperature, while volatile matter content decreased. Thus, the best biopellets were obtained at a temperature of 550°C. This study confirms the potential of bagasse and coffee husks as raw materials for biopellets through pyrolysis temperature optimization to support the development of sustainable biomass energy.

Overburden removal at Pit B did not meet the production targets for June and July 2025, which were set at 570,698.8 BCM and 400,986.56 BCM, respectively, while the actual production achieved was 507,071.66 BCM and 312,128.23 BCM. This study aims to determine the theoretical productivity of loading and hauling equipment and to identify the factors that hinder the achievement of production targets. The primary data used in this study include the cycle time of loading equipment, the cycle time of hauling equipment, bucket fill factor, and delay time. The secondary data required consist of swell factor, number of passes, bucket capacity, and available working time. The productivity of the loading equipment was 332.58 BCM/hour, while the hauling equipment achieved a productivity of 53.16 BCM/hour, with a match factor of 0.74. This indicates that the loading equipment experienced waiting time during loading operations due to the hauling equipment not operating optimally or at full capacity. The factors inhibiting the achievement of production targets include a narrow, waterlogged, and uneven working face; hard overburden material; a road grade of 16%, which exceeds the standard maximum of 12%; a curve road width of 15 m, which is less than the ideal minimum width of 19.95 m; undulating haul roads; narrow haul road width; and dusty road conditions.

L House is a house design that is shaped like the letter "L". This distinctive configuration offers flexibility in spatial arrangement and creates an interesting interaction between interior and exterior areas. L House by 022Studio is a work that combines modern aesthetics with traditional values and sustainability. Through a descriptive criticism method involving interviews with architects, literature studies, and analysis of design elements, this study aims to reveal the strengths and challenges in the application of modern design in a tropical context. L House successfully integrates space with nature through the use of local materials, flexible spatial layouts, and building orientations that optimize natural lighting and ventilation. In addition, this design also makes a significant contribution to the development of modern architecture in Indonesia by demonstrating that modern buildings can be adapted to local cultural and environmental contexts. L House is a good example of sustainable architecture that can inspire similar projects in the future.

The problems encountered are damage to the rubber wheel mount and universal/cross joints on the 90 m/hour capacity wood profile making machine, which can affect the uniformity and speed of wood profile making. Maintenance and repair planning aims to be able to create a maintenance and repair schedule for the 90 m/hour capacity wood profile making machine for the period 2026, estimate maintenance costs and the ratio of maintenance and repair costs to machine profits. The maintenance planning method includes collecting maintenance data from previous maintenance periods, reviewing the specifications of the wood profile making machine, estimating the age and price of components that are estimated to be damaged, estimating the cost and duration of dismantling and installing components that have been repaired in accordance with the provisions of the requirements for usable components or replacement spare parts, scheduling maintenance and repairs, estimating maintenance and repair costs for the period 2026, and determining the ratio of maintenance costs to profits. The planning results in the form of a maintenance-repair schedule for the period 2026; maintenance and repair costs in 2026, the ratio of maintenance costs to profits, and their implications indicate that the machine is still prospective and usable.

Gastric disease is a common health problem that can disrupt daily activities if not properly treated. To aid the initial diagnosis process, this study developed a web-based expert system capable of diagnosing various types of gastric disease based on the symptoms experienced by the user. This system uses the Dempster-Shafer method to address uncertainty in decision-making by combining a number of pieces of evidence in the form of symptoms to determine the level of confidence in a disease. The system was developed using the PHP programming language and a MySQL database and designed for easy browser access. Testing demonstrated that the system was able to provide fairly accurate diagnostic results that closely approximated the results of consultations with medical professionals. This system is expected to become an initial solution for the public in quickly and independently recognizing symptoms of gastric disease.

Waste from used Polypropylene (PP) and High Impact Polystyrene (HIPS) plastic is problematic in its management. The purpose of this research is to obtain the fatigue life of a mixture of used PP and HIPS plastics in its pure plastic. The research method is through the stages of mixing pure PP and 50% volume of used PP, pure HIPS and 50% volume of used HIPS, injection molding of R.R. Moore standard fatigue test specimens for pure PP, pure HIPS, pure PP + used PP, and pure HIPS + used HIPS, checking the straightness and smoothness of the molded specimen surface, fatigue testing with increasing serial loads, analysis of the bending stress curve (S) against fatigue life (N). The results showed that mixing used PP and used HIPS in pure plastic affected the fatigue life at the test speed (n)=2100 rpm for recycled PP was 9.84% shorter than pure PP, and at n=1600 rpm for recycled PP it was 9.32% shorter than pure PP, while at n=2100 rpm for recycled HIPS it was 4.45% shorter than pure HIPS, and at n=1600 rpm for recycled HIPS is 4.77% shorter than pure HIPS, while the fatigue life of pure PP is 1627704 cycles and the fatigue life of pure HIPS is 1291636 cycles or the fatigue life of pure HIPS is 20.65% shorter than pure PP, the implication of which is that the addition of used PP and used HIPS reduces the fatigue life to 9.84% for PP and 4.45% for HIPS.

Currently, patients experiencing early symptoms of skin disease caused by the exanthema virus are unable to immediately consult a dermatologist due to the high cost and limited time available for specialists in hospitals. Therefore, the author needs to develop an expert system application that can address this issue. Through this application, users can consult with the system, much like an expert, to diagnose their symptoms and find solutions to their problems. This expert system is designed to provide answers based on whether the symptoms are correct or not, or to provide several recommended answer choices based on the symptoms. To diagnose skin disease caused by the exanthema virus, the author used the Case-Based Reasoning method. The CBR method is a weighting technique that compares new cases with previous cases. The diagnosis is based on data provided by the patient and expert, which is then analyzed using case-based reasoning and stored as a knowledge database in the expert system. Therefore, this expert system can help identify solutions for problems experienced by patients suffering from skin disease caused by the Exanthema Virus.

Tulungagung Regency has the potential for culinary tourism that can be developed, one of which is traditional culinary. Although the Tulungagung Regency Government has presented a "Halal Culinary Area" and a "Pinka Culinary Tourism Area", the area has not fully provided an interesting visual and functional experience. Therefore, it is necessary to design a space that facilitates traditional culinary MSMEs as well as an educational and recreational place. This design carries the theme of contemporary tropical architecture by considering local climatic conditions, through the application of wide openings, cross ventilation, wide trellises, and the use of natural materials, as well as expressive styles with the shape of a rooster roof and the basic shape of an elliptical building as a symbol of adaptation to climate change and the economy in the business environment. The facilities in this design include traditional restaurants, educational bales, wiyata offices, prayer rooms, playgrounds and other supporting facilities that can attract the interest of the community and introduce traditional Tulungagung culinary.

The development of sustainable tourism facilities is one of the important efforts in increasing the attractiveness of destinations while preserving the environment. This study aims to analyze the implementation of ecological concepts in the development of glamping facilities in the Pearl Beach tourist area. The method used is a descriptive qualitative approach, with data collection through field observations, interviews with managers and tourists, and literature studies related to ecotourism principles and sustainable design. The results of the study show that the application of ecological concepts in glamping facilities in Mutiara Beach includes the use of environmentally friendly materials, integrated waste management, the application of energy efficiency, and designs that integrate the natural landscape without damaging the coastal ecosystem. The application of this concept not only improves the comfort and experience of tourists, but also contributes to increasing environmental awareness and strengthening the positive image of tourist destinations. In addition, this ecologically-conceptual glamping development model is expected to be a reference for the development of sustainable tourism facilities in other coastal areas, which prioritizes nature preservation and the welfare of local communities.

During the coal stockpiling process, the quality of coal may increase or decrease due to direct exposure to open environmental conditions, which can lead to changes in its characteristics. The longer the coal is stored in an open area, the more it undergoes changes caused by rainfall, heat, and air exposure, resulting in an increase in moisture content and ash content, while the calorific value decreases. Therefore, this research was conducted to determine the optimal coal stockpiling duration at the ROM coal stockpile to ensure that the calorific value does not significantly decrease. Coal sampling was carried out every two days from the initial time of stockpiling. After a two-month stockpiling period, the final coal quality results showed a total moisture of 13.89% (ar), inherent moisture of 15.95% (ad), ash content of 4.59% (ad), volatile matter of 40.3% (ad), and fixed carbon of 39.16% (ad). Based on these results, it can be concluded that the recommended storage duration for MCV-HS type coal at the ROM coal stockpile is 154 days. The laboratory analysis results obtained during the research indicate that the longer the coal is stored, the higher the moisture content and ash content become, while the calorific value continues to decrease. This occurs due to water absorption and oxidation reactions that take place during the coal storage period in the ROM coal stockpile.

This study aims to determine the relationship between learning motivation and learning outcomes in SMAW welding engineering among eleventh-grade students at SMKN 2 Solok. This research employed a quantitative method with a correlational approach. The population consisted of all students from classes XI TPM 1 and XI TPM 2, totaling 51 students, using a total sampling technique. Learning motivation data were collected through a validated and reliable questionnaire, while learning outcome data were obtained from post-test scores in the SMAW welding subject. Data were analyzed using the Pearson Product Moment correlation test with the assistance of SPSS software. The results showed a correlation coefficient of r = 0.783 with a significance value of 0.000 < 0.01, indicating a strong, positive, and statistically significant relationship between learning motivation and students’ learning outcomes. These findings suggest that higher learning motivation leads to better learning outcomes in SMAW welding engineering. Therefore, learning motivation plays an important role in improving students’ academic performance. This study is expected to provide useful insights for teachers and schools in developing instructional strategies that enhance students’ motivation and learning outcomes.

A research about study of sandstone slope stability using the Bishop Simplified method in Uu Samarinda has been conducted. This study was conducted to analyze the rebound number values of sandstone slopes, evaluate their stability level, and calculate the safety factor using the Bishop method. The results showed that the rebound number values were 22.34 at point 1, 19.83 at point 2, and 18.07 at point 3. The Uniaxial Compressive Strength (UCS) values at the observation points were 1.90 MPa, 1.62 MPa, and 2.21 MPa, respectively. Geological Strength Index (GSI) evaluation indicated a rating of 80–85, demonstrating intact/massive rock structure, fresh and unweathered rock surfaces, and very good rock quality. Based on the Bishop method analysis, the slope factor of safety in 6.525  with a probability of failure is 0.000%, indicating that the sandstone slope in Ulu Samarinda is highly stable even under external pressures such as heavy rainfall or minor earthquakes. This study provides crucial information on the mechanical characteristics and stability of sandstone slopes in ulu Samarinda, which can serve as a reference for technical planning, geotechnical risk mitigation, and the sustainable development of safe areas.