Publication Search

In general, school students buy snacks in the school canteen or street vendors (PKL) around the school. 2 The types of food sold are varied, ranging from healthy snacks to unhealthy snacks so that they can attract students to consume school snacks. Healthy snacks are foods that have sufficient and balanced nutrition and do not contain (contaminated) elements that can harm or damage health. This community service activity aims to educate healthy eating patterns to prevent food and drinks containing microbial contamination at Mariana Catholic High School, Medan. The method used is an educational approach through health counseling, interactive discussions, and demonstrations of hygienic practices, especially correct handwashing techniques and the importance of maintaining personal hygiene and the school environment. This activity was attended by 40 students as participants. The evaluation of the activity focused on one main indicator, namely student participation in hygienic behavior practices as a form of direct application of the material that has been given. The results of the activity showed that all participants (100%) followed the demonstrated hygienic practices, which indicates a very high level of participation and enthusiasm. These findings indicate that educational methods accompanied by hands-on practice are effective in increasing understanding and encouraging the adoption of clean and healthy living behaviors. Community service activities at Mariana Catholic High School in Medan have been shown to increase students' knowledge about the dangers of microbial contamination and the development of hygienic behaviors in daily life. Structured and ongoing education is an effective preventive measure to create a healthy and clean school environment.

This study examines the impact of industrial activities in Bontang City, a major center for natural gas processing and fertilizer production, which potentially increases heavy metal contamination in coastal waters. Specifically, the research focuses on the accumulation of lead (Pb) and copper (Cu) in Anadara granosa, a benthic bivalve selected as a bioindicator due to its capacity to accumulate pollutants. The study aims to analyze Pb and Cu concentrations in Anadara granosa tissues collected from the waters of Selangan Hamlet, Bontang City, as an indicator of local environmental quality. The research was conducted over a six-month period, involving shellfish and water sampling from four observation stations. Heavy metal analysis was performed using Atomic Absorption Spectrophotometry, and the results were evaluated against relevant environmental quality standards, including Government Regulation of the Republic of Indonesia Number 22 of 2021. The findings revealed the presence of Pb and Cu at all sampling stations, with varying concentrations. The highest Pb and Cu levels were recorded at the South Station, while the lowest concentrations were observed at the East and North Stations. Overall, the measured concentrations of both metals significantly exceeded established safety limits, indicating serious risks to aquatic ecosystems and human health. These results confirm Anadara granosa as an effective bioindicator of heavy metal pollution and highlight the urgent need for further studies and mitigation efforts.

The danger of cadmium contamination in water sources remains a crucial environmental issue due to its persistent nature and high toxicity level, which poses serious risks to human health and ecosystems. Cadmium is a non-biodegradable heavy metal that can accumulate in living organisms over time. The presence of these toxic Cd²⁺ ions is known to trigger damage to vital organs such as the liver and kidneys; therefore, reducing their concentration in aquatic environments is of paramount importance for environmental protection and public health safety. Among various treatment methods, adsorption is considered one of the most effective and economical techniques for removing heavy metal ions from contaminated water. In this study, the capability of mesoporous silica MCM-48-NH₂ as an adsorbent for Cd²⁺ ions was systematically evaluated. The adsorption performance was examined by investigating several important parameters, including contact time, solution acidity level (pH), and initial Cd²⁺ concentration. Furthermore, the adsorption mechanism and interaction between Cd²⁺ ions and the adsorbent surface were analyzed using Langmuir and Freundlich isotherm models. The results demonstrate that the adsorption process of Cd²⁺ ions onto MCM-48-NH₂ tends to follow the Langmuir isotherm model, indicating monolayer adsorption behavior, with a maximum adsorption capacity of 0.66 mmol g⁻¹.

Soil contamination by hydrocarbons, pesticides, heavy metals, and complex pollutants is rapidly increasing and degrading essential ecosystem functions. Physical or chemical treatments offer faster results, yet they are often costly, energy-intensive, and risk disrupting soil biological integrity without fully eliminating pollution sources. Microorganism-based bioremediation provides a more sustainable alternative by utilizing microbial metabolism to degrade or immobilize pollutants into less toxic and less mobile forms. This article presents a structured literature review on the roles and applications of microorganisms for bioremediation of contaminated soils, covering comparisons between single isolates and microbial consortia, dominant biological mechanisms, and ecological challenges in field application. A Systematic Literature Review approach was applied, using narrative synthesis and thematic clustering of national and international journals published between 2020 and 2025. The review indicates that single microbial isolates are commonly selected for specific pollutant targets, whereas microbial consortia are preferred for mixed or persistent contaminants due to metabolic synergy that enhances microbial adaptability and stepwise pollutant breakdown in highly polluted soils. Adaptive mechanisms such as EPS production and biofilm formation contribute to microbial resilience under stress and help retain contaminants within the soil matrix. Key challenges identified include inoculum stability under extreme conditions and limited microbial access to pollutants trapped in micro-soil pores. The findings highlight that microbial selection strategies must be tailored to pollutant characteristics and soil environmental conditions, while also emphasizing the potential of biofilm-based systems and organic carriers to support broader field implementation of microbial bioremediation.

Partial Denture (GTSL) is an ideal option for patients with missing teeth, with various materials such as thermoplastic nylon (flexible denture), acrylic resin, and metal. Heat-cured acrylic resin and thermoplastic nylon are the two most commonly used materials for denture bases. Denture bases must have sufficient mechanical strength to withstand chewing forces. Acrylic resin, made from polymethyl methacrylate, has become the gold standard in prosthodontics due to its affordability, ease of fabrication, and satisfactory functional results. However, acrylic resin tends to be rigid, brittle, and may cause soft tissue irritation. As an alternative, thermoplastic nylon offers high physical strength, resistance to heat and chemicals, as well as plastic and flexible properties. However, thermoplastic nylon tends to absorb water, change color, and is difficult to repair. Thermoplastic nylon-based dentures provide comfort, aesthetics, and good marginal adaptation, with less soft tissue irritation compared to acrylic resin dentures. Although both materials have comparable characteristics in terms of retention, stability, and durability, flexible dentures are more attractive to patients who prioritize comfort and aesthetics.

Zinc (Zn) is one of the most common heavy metal contaminants found in industrial wastewater and solid residues such as slag, electroplating waste, and metal ash. At excessive concentrations, Zn can cause environmental disturbances, including toxicity to aquatic organisms, disruption of microbial activity, and groundwater contamination. Long-term exposure may also lead to bioaccumulation and potential health risks to humans. This article presents a comprehensive literature review that discusses the chemical properties of Zn, its environmental behavior, and the development of recent treatment technologies within the last five years. Several techniques, including adsorption using modified or composite materials, biosorption utilizing microalgae and agricultural biomass, as well as solidification–stabilization with amendment agents such as biochar or iron-sulfide compounds, are evaluated and compared. The literature indicates that no single treatment method is universally effective for all waste types; therefore, hybrid or integrated treatment systems are considered more efficient and sustainable. Based on the reviewed evidence, this study proposes an engineering concept that emphasizes environmental safety, cost-effectiveness, and industrial applicability.

Background: Posterior tooth loss can impact masticatory function, aesthetics, and quality of life. Bridges are a restorative solution, but conventional pontic designs often make it difficult to maintain periodontal hygiene and health. Sanitary pontics offer a design that minimizes tissue contact, facilitates cleaning, and reduces plaque accumulation. Case report: A 23-year-old male patient lost his mandibular right first molar and sought to restore chewing function. After clinical and radiographic examinations, it was decided to restore the edentulous area of tooth 46 using a PFM bridge with a sanitary pontic design. Teeth 45 and 47 underwent abutment preparation, impressions, and fabrication of the bridge. Discussion: The sanitary pontic design has been shown to facilitate oral hygiene, especially under the pontic. The space between the pontic and the alveolar mucosa facilitates effective brushing or flossing, reducing plaque and the risk of gingival inflammation. PFM materials provide appropriate strength and durability for posterior restorations. Conclusion: A Porcelain Fused Metal (PFM) bridge with a sanitary pontic design is an effective restorative alternative for posterior tooth loss, improving hygiene and supporting long-term periodontal health.

This journal discusses the archive storage and maintenance system at the Lirik District Office, Indragiri Hulu Regency, using qualitative methods. The results of the study indicate that the archive storage system at the Lirik District Office has implemented manual and digital storage. Physical archive storage is carried out manually by arranging it based on the principle of the origin of the archive and the type of media, taking into account the environmental conditions of the storage room (temperature and humidity). Physical archives are stored in fireproof cabinets and coded folders. Digital archives are stored via Google Drive. There are regulations set to maintain confidentiality, limit access, and maintain the cleanliness of the storage room. Archive maintenance efforts include: (1) Maintaining the storage room with air conditioning and ventilation. (2) Cleaning the storage room and archives regularly. (3) Separating damaged archives; (4) Using fireproof metal archive cabinets; (5) Arranging archives neatly and using camphor. Overall, the implementation of the archive storage and maintenance system at the Lirik District Office has met expectations, although not yet optimal. This study concludes that the archive maintenance efforts carried out are quite good in maintaining the physical condition and information of the archives, although there is still room for improvement and optimization of the system.

Waste management remains a major challenge, particularly due to the lack of public awareness and habits in sorting waste from its source. Innovative technology-based solutions are needed to support more effective waste management systems. This study aims to design and develop an Internet of Things (IoT)-based smart trash bin capable of automatically sorting metal and non-metal waste. The system utilizes an ESP32 microcontroller as the main controller, an LJ12A3-4-Z/BY sensor to detect metal materials, an E18 sensor to detect non-metal materials, and an ultrasonic sensor to monitor bin capacity. The waste separation mechanism is operated by a servo motor controlled by the system, while the Blynk application is integrated for real-time monitoring and full-capacity notifications sent directly to the user’s smartphone. The research stages included hardware design, microcontroller programming, IoT platform integration, and functionality testing to ensure system performance and reliability. The results showed that the smart trash bin operated as expected, successfully identifying and separating metal and non-metal waste automatically, while also sending real-time notifications to the user when the bin approached full capacity. The implementation of this technology has the potential to modernize waste management processes, improve the efficiency of waste sorting, and reduce dependency on manual labor. Furthermore, this research opens opportunities for future development by integrating additional sensors and cloud-based data management systems to support smart city initiatives and sustainable waste management practices.

A target is needed for kicks and attacks. Currently, these targets are always held by the lecturer, which, when used, significantly wastes time in learning sessions. With the funded Community Service Program (PKM) activity, the lecturer developed his creativity by creating a target stand, which was still incomplete at the time. The results of this community service implementation will impact students in the Physical Education Department at Lambung Mangkurat University. Lecturers teaching martial arts courses have greatly benefited from the presence of this target stand. Survey data analysis results are still in progress and will be attached to the final report. In this case, the partner is a colleague within the Physical Education Department, with whom he has a collaboration in the construction and welding fields. 80% of sports equipment is made from hard materials such as steel. Therefore, the Department has a long-standing partnership with DTK (Dita Teknik Kontruksi). Furthermore, metal sports equipment is regularly maintained, and if damaged, the partner is ready to repair it at a certain capacity.

Population growth and lifestyle changes in Indonesia have led to complex waste management issues, negatively impacting social, health, and environmental sustainability aspects. To address this, a sustainable management approach that actively involves community participation is necessary. The concept of a Waste Bank, based on the 3R principles (Reduce, Reuse, Recycle), emerges as a strategic, community-based solution. This community service program aims to encourage active community participation in the Waste Bank program in Tanjung Uban Selatan, Bintan Regency, while supporting the realization of a Smart City based on intelligent and participatory environments. The methodology used is a qualitative approach to gain in-depth understanding. Primary data collection was carried out through interviews, participatory observations, and documentation studies. Key informants were purposively selected from various stakeholders, including Waste Bank administrators, local government representatives, and community members. The results show that, although initially challenging to increase community participation, the program has had a significant positive impact. It successfully shifted the community's view of waste as a valuable economic resource. Quantitatively, this is reflected in stable income from the sale of high-quality inorganic waste, such as metals and electronic waste. The program also led to strategic innovations, including sustainable education, waste savings incentives, social media use, and the "Dasi Umat" empowerment program. The success of this program, strengthened by awards at the district and national levels, makes it a model for sustainable waste management focused on community empowerment and supporting smart city development.

Al–Mg–Si aluminum alloys are widely utilized in engineering applications due to their low density, excellent corrosion resistance, and mechanical properties that can be modified through heat treatment. This study investigates the effect of homogenization on the microstructure and hardness of Al–Mg–Si alloys produced by the squeeze casting process. The experimental procedure involved alloy melting, squeeze casting at 76 MPa using preheated metal molds, followed by homogenization at 400 °C for 4 hours. Microstructural characterization was performed using optical microscopy to examine the dendritic morphology and measure the secondary dendrite arm spacing (SDAS). Mechanical properties were evaluated through Vickers microhardness and Rockwell macrohardness testing. The results show that homogenization increases the SDAS from 32.59 μm to 36.88 μm and decreases the volume fraction of interdendritic phases from 15.51% to 13.57%. Furthermore, microhardness decreased from 50.22 VHN to 38.58 VHN, while macrohardness decreased from 54.60 HRE to 46.64 HRE. These reductions are attributed to the partial dissolution of Mg₂Si precipitates into the aluminum matrix during homogenization. Overall, this research provides valuable insight into the optimization of initial heat treatment parameters for Al–Mg–Si alloys produced by squeeze casting. The findings highlight the role of homogenization in improving microstructural uniformity and preparing the alloy for subsequent deformation processes such as cold rolling and extrusion, particularly for structural components used in mining and heavy transportation industries.

Welding work on ships carries high risks of health disturbances due to exposure to heat, smoke, chemicals, and poor ergonomic work positions. This study aims to identify potential occupational health hazards among welders working on the MV KAREEM ship at PT. Samudra Marine Indonesia in 2025. The study uses a descriptive observational design with total sampling technique, involving 30 welders. Data were collected through direct observation using observation sheets and documentation in accordance with the welding SOP. The results of the study revealed five categories of health hazards. Physical hazards included excessive heat, noise, and poor lighting. Chemical hazards included welding fumes, metal dust, and toxic gases. Biological hazards arose from exposure to microorganisms in the work environment. Ergonomic hazards were related to awkward posture, prolonged static positions, and manual handling loads. Psychosocial hazards included long working hours, high workload, and conflicts among workers. The findings emphasize that welders are prone to health disturbances due to various risk factors. Preventive measures, including improving the work environment, implementing stricter safety standards, and providing occupational health education, are essential to reduce these risks.

In a global economic situation full of uncertainty, gold is one of the most popular investment instruments because it is considered stable and has a high intrinsic value. PT Antam Tbk UBPP Precious Metals is one of the precious metal providers trusted by the public. However, purchasing decisions are not only influenced by product quality, but also by price and customer trust factors. This study aims to determine the effect of price and customer trust on purchasing decisions for precious metals at PT Antam Tbk UBPP Precious Metals. This study uses quantitative statistical methods with data collection techniques through questionnaires to 110 respondents selected using purposive sampling techniques, namely respondents who have purchased gold at PT Antam Tbk directly or online. Data analysis was carried out by validity test, reliability test, classical assumption test, multiple linear regression test, hypothesis testing and coefficient of determination test using SPSS version 25. This research was conducted from April-June 2025. The results showed that the price partially had a positive and significant effect on purchasing decisions (3,728>1,982). customer trust also partially had a positive and significant effect on purchasing decisions (6,591>1,982) and price and customer trust simultaneously had a positive and significant effect on the decision to purchase precious metals at PT Antam Tbk UBPP Precious Metals (69,693>3,08).

Shrimp is a food ingredient that has perishable characteristics, so it requires proper handling to maintain product quality and safety. This study aims to understand the application of the quality system in frozen shrimp processing based on the principle of Hazard Analysis Critical Control Point (HACCP) at PT Dachan Mustika Aurora Tarakan. The research was carried out during the period from July to December 2024 with a qualitative descriptive approach. The results of the study show that the frozen shrimp processing system has followed the principles and stages of HACCP in general, starting from the receipt of raw materials, temperature checks, organoleptic tests, laboratory tests, processing with temperature control, washing, sorting, packaging, to storage in cold storage. However, there are still critical points at the Metal Detector washing and inspection stages, with the potential for significant danger in the form of metal chip contamination. The quality control process is carried out in layers to ensure that the final product meets national and international standards. The implementation of HACCP has consistently proven to be effective in improving food safety, maintaining the quality of frozen shrimp, and strengthening the competitiveness of products in the export market. These findings provide recommendations for the seafood processing industry to strengthen surveillance systems at critical points and improve personnel training to minimize the risk of contamination and ensure the sustainability of product quality.

PT Sinar Semesta is a company engaged in the metal casting industry. In its production process, defects were still found during the period from March 2023 to February 2024. Out of a total production of 4,950 units, there were 1,004 defective units, consisting of 534 units with flow error defects and 470 units with porosity defects. To address this issue, quality control methods such as Statistical Quality Control (SQC) and Fault Tree Analysis (FTA) are necessary to minimize product defects, improve quality, and maintain high standards. Based on the Pareto diagram, the most dominant defect percentages are flow error defects at 53.19% and porosity defects at 46.81%. The control chart shows points beyond the upper control limit (UCL) occurring in April with 148 units, May with 145 units, and October with 149 units, and below the lower control limit (LCL) occurring in August with 35 units, January with 36 units, and February with 32 units. Based on the fault tree analysis, five main factors causing defects were identified: human, machine, raw material, method, and environment. Proposed improvements include operator training, routine machine maintenance, accurate raw material measurement, use of high-quality raw materials, pre-pouring temperature checks, increased supervision, and environmental improvements.

Acid mine drainage (AMD) is one of the major environmental problems arising from coal mining activities. AMD is formed through the oxidation of sulfide minerals, resulting in acidic water with high concentrations of dissolved heavy metals. This condition is characterized by elevated levels of Fe, Mn, and total suspended solids (TSS), which, if left untreated, can pollute nearby water bodies, damage aquatic ecosystems, and pose risks to human health. Therefore, effective, eco-friendly, and low-cost treatment methods are needed to minimize the negative impacts of AMD. This study aims to investigate the effect of activated carbon derived from sugarcane bagasse as an adsorbent for reducing Fe, Mn, and TSS levels in AMD at the sump of PT Alreksa Bara Mitra. The selection of sugarcane bagasse is based on its abundance as an agro-industrial waste and its high lignocellulosic content, making it a potential raw material for activated carbon. The research involved the preparation of activated carbon through carbonization and activation processes, followed by its application to AMD samples with variations in adsorbent dosage and contact time. Laboratory analyses were conducted to measure the concentrations of Fe, Mn, and TSS before and after treatment. The results showed that sugarcane bagasse-based activated carbon significantly reduced Fe, Mn, and TSS concentrations. The highest removal efficiencies were achieved under optimum conditions, reaching 93.14% for Fe, 95.05% for Mn, and 85.04% for TSS. These findings demonstrate that activated carbon from sugarcane bagasse has a strong adsorption capacity for dissolved metals and suspended solids in AMD. In conclusion, sugarcane bagasse-derived activated carbon has potential as an environmentally friendly and cost-effective alternative for AMD treatment, while simultaneously providing added value to agro-industrial waste. This research is expected to serve as a reference for the development of more sustainable mine wastewater treatment methods.

This study aims to analyze the welding results between two commonly used methods, namely Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW), using radiographic testing methods. Welding is an important process in industry that affects the quality and strength of metal joints. In this study, we will examine the quality of welding results from both methods through radiographic testing, which serves to detect defects in welded joints. The GTAW method is known for its cleaner results and minimizes defects, while SMAW is often used because of its convenience and lower cost. The welding process is a crucial factor in ensuring the durability and performance of metal structures, and selecting the right welding method is essential for specific industrial applications. This study will compare the two methods based on the results of radiographic and tensile tests, evaluating factors such as weld strength, defect occurrence, and structural integrity. The analysis will also examine the advantages and disadvantages of each method in terms of weld quality, cost-effectiveness, and practical applications in different industries. It is hoped that the results of this study can provide deeper insights into the selection of the right welding method for industrial applications, as well as contribute to the development of welding technology. Furthermore, the findings will support improvements in quality control and provide a scientific basis for future welding practices in various manufacturing sectors.

Well water is still one of the main sources of daily water supply for the residents of the Candi Muaro Jambi area. The dependence on well water makes it vital for consumption, cooking, and other domestic activities. However, with the increasing human activity, the development of tourist areas, and environmental changes in the surrounding area, the quality of the well water is at risk of being affected. This study aims to evaluate the feasibility of well water from an environmental and health perspective based on physical, chemical, and biological parameters, referring to the clean water quality standards set by the Ministry of Health of the Republic of Indonesia. The research employs a descriptive quantitative method, with well water samples taken from several points around the residential areas in the Candi Muaro Jambi region. The analyzed parameters include temperature, color, odor, turbidity, pH, nitrate content, metal content (Fe and Mn), and the presence of coliform bacteria. Laboratory test results show that most of the well water samples still meet the established physical and chemical standards, but some wells were found to have coliform levels exceeding the recommended threshold. This condition indicates contamination, most likely from domestic waste, particularly from household sanitation systems that are not ideally located relative to the wells. While the well water in the study area is generally still suitable for daily use, it is recommended that the community performs simple water treatment, such as boiling or filtration, before direct consumption. These measures are crucial to reduce contamination risks and ensure the water's quality for safe consumption and health.

The magnesium alloy AZ31B is increasingly used in biomedical applications, particularly as an implant material, due to its relatively low aluminum content and mechanical properties that closely resemble those of bone. Additionally, AZ31B exhibits corrosion resistance that is suitable for biological environments. These properties make it a promising material for bone implants. However, one of the main challenges in using magnesium is its high degradation rate in the body, which can affect the stability and function of the implant. Therefore, surface modification is necessary to control the degradation rate and enhance the material's durability. One effective method to reduce the corrosion rate of AZ31B is the Plasma Electrolytic Oxidation (PEO) technique. PEO can form a hard, protective oxide layer on the surface of the metal, which helps improve its corrosion resistance. This study aims to explore the effect of the mass composition of hydroxyapatite (HAp) and tricalcium phosphate (TCP) on the PEO coating formed on the AZ31B substrate. The compositions used in this study were 70%:30%, 50%:50%, 40%:60%, and 60%:40%, with an electrolyte solution containing Na₂SiO₃ (2.5 g/L) and KOH (2 g/L). Corrosion characteristics of the coating were evaluated using two methods: weight loss and polarization tests. The results showed that the 70%:30% HAp:TCP composition provided the most optimal results. The polarization test recorded a corrosion rate of 0.22 mpy, while the weight loss test showed a corrosion rate of 0.29 mpy. These findings indicate that the PEO coating with the 70%:30% HAp:TCP composition effectively reduces the corrosion rate of AZ31B, enhancing its potential for biomedical implant applications, particularly in environments where corrosion resistance is crucial for long-term performance in the body.