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The amalgamation and flotation methods are widely used by miners because the methods are simple, fast and easy. The purpose of this study was aims to test the effectiveness of gold recovery using the amalgamation and flotation methods in conventional gold processing. The research methods used were observation and testing using the amalgamation and flotation methods in conventional gold processing. The effectiveness analysis was carried out by calculating the percentage of gold produced in the amalgamation and flotation processing methods. The test was carried out on 10 samples, each weighing 10 kg. The amalgamation process used a Hg solution, while flotation used a detergent reagent. The total primary gold processing using the amalgamation method was 11.46 grams, while the total primary gold recovery using the flotation method was 12.15 grams. The results of gold processing using the flotation method were higher than those using amalgamation because flotation can separate gold more efficiently from ore containing various impurity minerals. Meanwhile, the amalgamation method, which uses mercury, tends to be less effective and loses some of the gold because it only binds very fine and dispersed gold particles, while flotation can handle ore with lower gold content and larger gold particles.

The increasingly complex global energy problem drives the need for efficient, low-cost, and environmentally friendly energy storage systems. This study aims to analyze the power performance of two symmetric supercapacitor prototypes using Nitrogen-doped Graphene-Like Carbon (N-GLC) as the electrode material and 1 M  as the electrolyte, with different electrode substrates: aluminum and copper. Both prototypes were tested through charging and discharging processes using resistive loads of 470 ohms and 560 ohms for 5 minutes. The analyzed parameters include voltage, current, power, and output energy. The results show that the aluminum electrode achieved a higher maximum charging power of up to 18 mW; however, its energy discharge efficiency was very low at only 0.87%. In contrast, the copper electrode demonstrated a more balanced charging and discharging performance with an energy discharge efficiency of 19.4%. Analysis also indicates that the copper substrate maintains better voltage stability after 6 hours of storage compared to aluminum, which experienced significant degradation. Thus, the copper electrode is superior in maintaining the power and stability of a simple N-GLC-based symmetric supercapacitor system.

This research aims to analyze the influence of thermal conditions; specifically the temperature difference between the test object and the environment; on the characteristics of air flow and heat transfer around it. The object of this study is a test piece subjected to free air flow under various temperature conditions; focusing on the convection heat transfer phenomenon. The main problem addressed is how temperature variations affect the convection heat transfer coefficient; heat transfer rate; and heat flux; as well as changes in air velocity and pressure profiles. Therefore; the objective of this research is to quantitatively compare and assess these thermal and fluid parameters through an experimental study approach and Computational Fluid Dynamics (CFD) simulation. The methodology involves direct measurement of temperature and pressure parameters under low and high-temperature conditions; which are then processed to determine the convection coefficient (); heat transfer rate (); and heat flux (). The main findings indicate that at low-temperature conditions; the heat transfer coefficient () was found to be 53.26 ; the heat transfer rate () was 24.99 W; and the heat flux () was 537.87 ; with a pressure drop of 0.86 Pa. In conclusion; thermal conditions play a crucial role in determining the dynamics of air flow and the efficiency of heat transfer; the greater the temperature difference (); the higher the potential heat transfer rate; establishing a strong correlation between thermal conditions and the convection phenomenon.

Population growth and socio-economic activities increase traffic volume, affecting the performance of the Raden Kusno – A. Djaelani – Sujarwo signalized intersection. This study aims to analyze the intersection’s current performance, estimate its condition over the next five years, and formulate alternative treatment strategies. The research data include geometric characteristics, signal timing, vehicle speed, and traffic volume obtained from CCTV recording over a three-day observation period from moning to evening, as well as population and vehicle data for projection. The intersection performance was analyzed using the PKJI 2023 approach and VISSIM simulation. Under current conditions, the intersection operates at LOS E with delays of 45,12 seconds (PKJI 2023) dan 60,56 seconds (VISSIM). In the five-year projection, delays increase to 48,97 seconds with LOS E (PKJI 2023) and 131,29 seconds with LOS F (VISSIM). Modifying the signal from four to three phases with a 70-second cycle improves the current condition to LOS C, with delays of 24,50 seconds (PKJI 2023) and 29,43 seconds (VISSIM). For the five-year projection, adding a continuous left-turn lane results in LOS D with 27,04 seconds (PKJI 2023) and LOS C with 32,01 seconds (VISSIM).

Self-Compacting Concrete (SCC) requires a high cement content, which contributes to increased carbon emissions; therefore, this study evaluates the effect of partial cement substitution with fly ash (5%, 10%, and 15%) and the addition of Polyethylene Terephthalate (PET) waste (0.5% and 0.7%) on the mechanical properties of SCC with a target strength of f’c 30 MPa. The research employed laboratory experimental methods, including fresh concrete tests (slump flow, L-box, and V-funnel) and hardened concrete tests (compressive, tensile, and flexural strength) at 7 and 28 days. The results indicate that fly ash substitution enhances compressive strength, with the highest value of 49.59 MPa achieved at 5% fly ash at 28 days, exceeding normal concrete (34.73 MPa). The addition of PET tends to reduce compressive strength due to increased porosity; however, it significantly improves flexural strength, as the combination of 5% fly ash and 0.5% PET achieved 4.7 MPa compared to 2.9 MPa for normal concrete. Overall, the combination of fly ash and PET waste shows potential for application in structural elements requiring high flexural performance.

Takaras River is a river basin that is vulnerable to pollution, particularly from the mercury usage in small-scale gold mining. This study aims to identify water quality based on mercury (Hg)and pH levels in the Takaras River. Samples were taken at two locations using a purposive sampling method. Results showed indications of mercury use on former gold mining land around the Takaras River altought the mercury content level was below 0.075 µg/L or 0.00075 mg/L in sample 1 and 2. Based on the test results, the acidity level (pH) in the two water samples from Takaras River is 3.86 and 3.84 in sample 1 and 2, compared to the maximum pH quality standard of 6-9 for Class II water, it is concluded that the scale of acidity in Takaras River is very low, indicating that the water quality in the Takaras River is highly acidic, abnormal, and shows signs of serious pollution. The implications of low pH levels in the Takaras River can cause damage to the Takaras River ecosystem, a decline in soil quality and fertility, and an increase in heavy metal toxicity in the environment surrounding the river.

The coal mining industry requires accurate stockpile volume measurements for inventory and production reporting. Conventional methods have limitations in accuracy, efficiency, and safety. This study compares the accuracy and efficiency of coal stockpile volume measurements using a Terrestrial Laser Scanner (TLS) Leica MS60 and an Unmanned Aerial Vehicle (UAV) DJI Matrice 4E, validated by the ASTM D6172-98 standard. Conducted on five Run of Mine (ROM) coal stockpiles covering 13,500 m² at PT XYZ, Lahat, South Sumatra, the TLS method used 43 scan positions, while the UAV employed 430 aerial images with specific flight parameters. Data were processed using Leica Infinity, Surpac, and Agisoft Metashape. The results showed volumes of 94,076 m³ (TLS) and 94,965 m³ (UAV), with a difference of 889 m³ (0.95%). Volume deviations ranged from 0.48% to 1.89%, with an average of 1.42%, all within the ASTM tolerance (<2%). Time efficiency analysis revealed that the UAV method required 200 minutes (3.33 hours), saving 63.3% (approximately 6.17 hours) compared to the TLS method (570 minutes). The largest efficiency gain occurred during field data acquisition, with an 85% reduction in time. This study confirms UAV photogrammetry as a valid, accurate, and efficient alternative for coal stockpile volume measurement in mining.

This research aims to design and develop a prototype wave power plant that utilizes the vertical motion of a buoy as a source of mechanical energy, which is then converted into electrical energy using a recoil starter mechanism. The system is designed to be installed at the stern of a prototype ship. The vertical movement of the buoy caused by ocean waves is transmitted to the recoil starter through a drive rope, producing a stable one-way rotational motion. This rotation is further transmitted to a gearbox to increase rotational speed before driving a DC generator. The electrical energy generated is stored in a 12 VDC battery, supported by a buck–booster converter to stabilize the output voltage. This study employs an experimental engineering approach to evaluate system performance based on empirical test data. The main components of the system include a buoy as a wave energy collector, a recoil starter as the initial rotating mechanism, a DC generator as the electrical energy producer, a buck–booster converter as a voltage regulator, a 12 VDC battery as an energy storage unit, and a monitoring system based on an ESP32 microcontroller integrated with a PZEM-017 sensor. Experimental results show that the recoil starter operates effectively in driving the generator under both no- load and buoy-loaded conditions. Increases in generator rotational speed are directly proportional to increases in output voltage and current. The PZEM-017 sensor demonstrates a high level of measurement accuracy, approaching 100% when compared with a multimeter. Overall, the proposed wave power generation system functions reliably and shows potential for further development as a small-scale alternative renewable energy source.

This research is motivated by the importance tank cleaning process on tankers to prevent cargo contamination, maintain cargo quality, and ensure crew safety. MT. Marina Prosperity, a chemical/oil tanker, uses the Butterworth system as the primary method for tank cleaning at every cargo change. However, in practice, technical and operational constraints are still found that affect the results of tank cleaning. The research method used is descriptive qualitative with data collection techniques through direct observation on the ship, interviews with the Chief Officer and Boatswain, and documentation studies in the form of log books and SOPs. Data were analyzed by focusing on three aspects, namely work efficiency, work safety, and operational procedures for using Butterworth. The results show that the use of Butterworth can increase time and energy efficiency compared to manual methods, with an average cleaning time of 2–4 hours per tank depending on the type of cargo. From a safety aspect, Butterworth reduces the need for crew to enter the tank, thereby reducing the risk of exposure to chemicals and hazardous atmospheres. However, work effectiveness and safety are greatly influenced by the condition of the equipment, the stability of water pressure, and the crew's discipline in implementing the SOP. On several occasions, steps such as nozzle cleaning, manual mopping, and safety meetings were not consistently performed, resulting in residual load in certain areas. With routine equipment maintenance, close supervision, and ongoing crew training, Butterworth can be optimized to produce more effective, safe, and standards-compliant tank cleaning process.

The increasing demand for electrical energy and the limited availability of fossil fuels have driven the development of renewable energy sources, including marine current energy, which remains underutilized in coastal and remote maritime regions. This study presents the design and realization of a small-scale marine current power generation prototype using a horizontal axis propeller turbine with a NACA S814 blade profile and analyzes the effect of turbine rotational speed on electrical power output. The system converts marine current kinetic energy into mechanical energy through turbine rotation and subsequently into DC electrical energy using a generator, which is stabilized by a Buck–Boost Converter and Maximum Power Point Tracking (MPPT) for charging a 12 VDC battery. Real-time monitoring of electrical and mechanical parameters is implemented using an Internet of Things (IoT)–based system comprising an ESP32 microcontroller, a PZEM-017 sensor, and an RPM sensor. Experimental results demonstrate a positive correlation between water flow rate, turbine rotational speed, and generator output voltage. The system begins operating at a minimum flow rate of 35.2 L/s at 56 RPM, producing 0.2 V, while optimal performance is achieved at 45.3 L/s and 516 RPM, generating up to 13.3 V. These results indicate that the proposed prototype is a viable alternative renewable energy source for marine applications.

Time delays and cost overruns remain major problems in building construction projects, particularly in concrete structural works that dominate project duration and cost. This study aims to evaluate the application of re-engineering in concrete structural work methods on the time and cost performance of multi-storey building projects. A quantitative approach using a case study method was employed through comparative analysis between the existing method and alternative methods. The analyzed alternatives include ready-mix concrete with Sika Viscocrete 8007 admixture and semi-system formwork as Alternative I, ready-mix concrete with system formwork as Alternative II, and ready-mix concrete with Sika Viscocrete 8007 admixture combined with system formwork as Alternative III. The results show that all alternatives perform better than the existing method with a duration of 243 days. Alternative I reduced the duration to 208 days with cost efficiency of IDR 55,781,730 or 0.214 percent. Alternative II reduced the duration to 203 days with cost efficiency of IDR 187,553,261 or 0.724 percent. Alternative III achieved the best performance with a duration of 168 days, accelerating 75 days and providing the highest cost efficiency of IDR 243,334,991 or 0.941 percent. The study concludes that re-engineering effectively improves project time and cost performance, with Alternative III as the optimal method.

Submarine pipelines are vital infrastructures in aviation fuel distribution, carrying high risks of operational disruption, safety issues, and environmental pollution. In 2025, the aviation fuel receiving submarine pipeline at Integrated Terminal Ampenan was deformed due to mechanical pulling by MT Anargya I, causing system shutdown. This incident created risks of seawater intrusion, marine pollution, and potential fuel shortages at Lombok International Airport. This study evaluates the effectiveness of applying a double-ended draining method combined with an oil bubble trap as a fast, safe, and sustainable solution for submarine pipeline repair. Using a case study and descriptive-analytical approach based on the Continuous Improvement Program (CIP), the research analyzed quality, cost, delivery, safety, environmental, and workforce aspects. The results showed the method effectively drained aviation fuel without seawater contamination, prevented marine spills, maintained fuel quality within specifications, and completed repairs before critical stock levels were reached. Additionally, it provided significant cost savings compared to emergency supply operations and achieved zero safety incidents and environmental pollution. The integration of double-ended draining and oil bubble trap proved to be an effective, adaptive innovation with strong potential for replication and standardization in other aviation fuel submarine pipeline systems.

Indonesia is in an earthquake-prone region, therefore, designing building constructions that can withstand seismic loads is crucial in civil engineering. Reinforced concrete shear walls are one of the vertical structural fundamentals that are effectively used in multi-story buildings to withstand lateral forces due to earthquake and wind loads. Structures that use shear walls can increase stiffness and reduce horizontal deviations (deflections) of buildings, which contribute to the stability and safety of structures based on the SNI 1726:2019 standard. This study aims to analyze the effect of shear wall configurations on deviation and torsion requirements in multi-story building planning. The study object is a 6-story reinforced concrete building model in a specific earthquake zone. The design and modeling were performed using structural analysis software, taking into account columns, beams, slabs, and shear walls. The analysis results show that optimal placement of shear walls at the building edges significantly reduces horizontal drift, torsion, and shear forces, and improves the structural performance level compared to structures without shear walls or those with less effective placement. Structures with shear walls have optimal stiffness in absorbing lateral forces, making them more resistant to damage from the planned earthquake.

Healthcare is an integral part of health development in Indonesia, which aims to optimally improve public health. Hospitals, as healthcare facilities, are required to provide quality, safe, and patient-centered services. Service quality is a key indicator of service success, as good service impacts patient satisfaction. One of the most important services in hospitals is obstetrics, which directly relates to maternal and infant health, making patient satisfaction a crucial aspect. Midwives, as professional healthcare workers, play a strategic role in providing comprehensive, sustainable, and patient-centered midwifery care. This study aims to analyze the influence of healthcare facilities and midwife performance on patient satisfaction through service quality. The method used is a quantitative study with an analytical approach and a cross-sectional design. The results of the multiple linear regression test indicate that midwife performance has a more dominant influence on service quality than healthcare facilities. Meanwhile, regarding patient satisfaction, service quality is the most dominant factor, followed by midwife performance and healthcare facilities. The conclusion of this study is that service quality reflects the overall patient experience and is a key factor in improving patient satisfaction.

Fertilization serves as a fundamental component of crop cultivation, wherein the application of mineral nutrients is crucial for plant nourishment, facilitating various physiological processes critical for growth and development. The objective of this study is to establish an optimal recommended dosage that enhances cabbage growth and yield. The experimental design employed in this study was a randomized block design with four replications. The treatments consist of seven fertilization levels, as follows: No fertilization with nitrogen (N), phosphorus (P), or potassium (K) (P0), reference fertilization (P1), 0.5 dose of unbalanced compound fertilizers (P2), 0.75 dose of unbalanced compound fertilizers (P3), 1.0 dose of unbalanced compound fertilizers (P4), 1.25 dose of unbalanced compound fertilizers (P5), and 1.5 dose of unbalanced compound fertilizers (P6). The experiment indicated that the application of unbalanced compound fertilizers enhances cabbage plant growth, as evidenced by increased plant height and leaf number compared to the control treatment. Additionally, fertilization improves yield components relative to untreated plants. The application of 0.5 doses of unbalanced compound fertilizers proves agronomically effective, yielding the highest relative agronomic effectiveness at 169%, meaning a 1.69-fold increase in yield. Economically, the same dosage is also highly beneficial, achieving the highest R/C ratio of 2.35 and generating a profit of Rp. 14,365,150. The study results confirm that unbalanced compound fertilizers were both agronomically effective and economically advantageous. The recommended dosage for cabbage cultivation is 134 kg/ha, applied in two stages: 50% at 1 WAT (weeks after transplanting) and the remaining 50% at 4 WAT.

The food and beverage industry in Indonesia is growing rapidly through digital marketing, particularly through the role of influencers in influencing consumer preferences and purchase intentions. Several influencers are no longer merely collaborating with brands, but are also becoming business owners by leveraging their personal branding and follower base. However, when promoting their own products, the effectiveness of these strategies on purchase intentions is not always consistent. This study aims to examine the influence of the Theory of Planned Behaviour on purchase intention and analyse the role of Parasocial Relationship through influencer authenticity and influencer trustworthiness in regional cuisine at RM Padang Payakumbuah. The research uses a quantitative approach with data from 182 respondents in the Special Region of Yogyakarta, analysed using PLS-SEM. The results show that attitude and influencer authenticity do not have a significant effect on purchase intention, while subjective norm and perceived behavioural control have a significant effect. Furthermore, influencer trustworthiness strengthens the relationship between perceived behavioural control and purchase intention. These findings emphasise the importance of social recommendations, ease of purchase access, and building trust towards influencers.

This study aims to analyze the influence of workforce agility, job satisfaction, and job engagement on employee adaptive performance at PT. MMT Buana Logistik. The dynamic logistics industry requires employees who have high adaptability to technological changes and operational demands. This type of research is quantitative causality with an explanatory approach. The population in this study were all employees of PT. MMT Buana Logistik, totaling 49 people, with the sampling technique used saturated sampling (census). Data were collected through questionnaires with a 5-point Likert scale. Data analysis techniques used included instrument testing (validity and reliability), testing of classical assumptions (normality, multicollinearity, and heteroscedasticity), and multiple linear regression analysis. Hypothesis testing was carried out through t-tests (partial), F-tests (simultaneous) and coefficient of determination (R2). The results showed that workforce agility, job satisfaction, and job engagement partially and simultaneously have a positive and significant influence on employee adaptive performance. These findings imply the importance of managing work flexibility, fulfilling employee satisfaction, and increasing work engagement to build adaptive human resources to support company competitiveness in the logistics industry.  

This study investigates the impact of TikTok Live, viral content, and Fear of Missing Out (FOMO) on the purchasing decisions of Gen Z consumers in Jombang City for food and drink products. Social media, particularly TikTok, has rapidly expanded and functions as a potent digital marketing instrument. It influences consumer behavior through live broadcasting and the dissemination of viral content. The objective is to examine the influence of these three factors on purchasing decisions. This study employs a quantitative methodology. The data was obtained from surveys administered to 60 Gen Z participants who purchased food or beverages following exposure to TikTok advertising. Samples were selected by purposive sampling. Data were examined using multiple linear regression with SPSS software. Findings indicate that TikTok Live exerts a favorable and substantial impact on purchasing decisions. Viral material exerts no substantial impact. FOMO exerts a detrimental and substantial impact. The results indicate that TikTok live streaming effectively enhances consumer purchases, especially within the food industry.  

Investment decisions in pharmaceutical manufacturing companies listed on the Indonesia Stock Exchange (IDX) are influenced by fundamental analysis and stock price fluctuations. Stock prices reflect market perceptions shaped by profitability, liquidity, and capital structure. This study examines the effects of Return on Assets (ROA), Current Ratio (CR), and Debt-to-Equity Ratio (DER) on stock prices, both partially and simultaneously. Using a quantitative approach, the study analyzes secondary data from audited financial statements and stock prices of 12 pharmaceutical companies during 2022–2024, totaling 36 observations. Panel data regression with EViews 12 is applied. Results show that ROA and DER have positive and significant effects on stock prices, while CR has a negative but insignificant effect. Simultaneously, all three variables significantly influence stock prices, with an adjusted R² of 73%, indicating strong explanatory power. Profitability (ROA) is the most influential factor, followed by capital structure (DER), while liquidity (CR) shows no significant impact.

This research reconstructs the concept of the ideal human being in Aristotelian philosophy and formulates its implications for contemporary character education. The study is grounded in modern educational challenges that require not only intellectual mastery but also the cultivation of complete character based on virtue. Using library research with a hermeneutic approach, this study critically interprets Aristotle’s key concepts, particularly eudaimonia, phronesis, and virtue ethics, and contextualizes them within current educational needs. Data were collected from relevant primary and secondary literature and analyzed through thematic and conceptual analysis to identify the relationship between Aristotelian ideas and character education. The findings show that the ideal human being, according to Aristotle, is one who achieves eudaimonia through the balanced development of moral and intellectual virtues, guided by phronesis as practical wisdom. Education is therefore understood as a gradual process of character formation through habituation, experience, role modeling, reflection, and ethical deliberation. This study proposes five strategies for Aristotelian character education: virtue habituation, experiential learning, educator role modeling, ethical deliberation, and context-based integral education. The study contributes a virtue-based educational model that emphasizes wisdom, responsibility, virtue, and the realization of the good life within society.