Global climate change has caused changes in rainfall patterns in various regions, including North Jayapura District, Papua Province. This study aims to analyze changes in rainfall characteristics in the region over the past two decades (2004–2023) using GSMaP satellite data. The analysis was carried out on the average monthly rainfall, annual rainfall, decadal trends, hourly rainfall intensity frequency, and daily rainfall duration. The results showed a decrease in annual rainfall accumulation in the 2014–2023 decades compared to the previous decade (2004–2013), with a difference of around 5,000 mm. The seasonal rainfall pattern still shows concentration in January to March, but with a significant decrease in these wet months. In addition, there was an increase in the frequency of short-duration rain (<1 hour) and moderate to very heavy rain, although the frequency was still relatively small. The high variability of annual rainfall also indicates an increasingly large climate. These findings indicate that North Jayapura District faces the risk of increasing extreme rainfall events and decreasing water availability in the long term. Therefore, adaptation efforts are needed through improving early warning systems, conservation of air catchment areas, and integration of satellite data and field observations in air resource management planning.

The 2011 Tohoku tsunami stands as one of the most catastrophic natural disasters in Japan’s history, resulting in massive loss of life, extensive property damage, and severe disruption to infrastructure along the northeastern coast. This study aims to examine the physical characteristics of the Tohoku tsunami and critically evaluate the factors that led to the failure of Japan’s disaster mitigation systems. Utilizing an essay-based synthesis approach, this analysis draws from a range of previous research findings and post-disaster assessments. The tsunami was caused by a 9.0 magnitude megathrust earthquake off the eastern coast of Honshu, generating wave heights that exceeded 10 meters in several locations. The tsunami’s immense energy produced destructive currents that penetrated deep inland, surpassing the protection capabilities of existing coastal defenses.The study identifies several contributing factors to the mitigation system’s shortcomings: the design limitations of seawalls, which were not built to withstand such extreme events; delays and limitations in the early warning system’s ability to reach all at-risk populations in time; and inadequate public preparedness, as the event exceeded historical precedents and training scenarios. These vulnerabilities highlight the need for integrated, adaptive disaster risk management strategies.Drawing lessons from Japan’s experience, this study proposes recommendations for improving tsunami mitigation efforts in Indonesia. Key suggestions include reinforcing and redesigning coastal defense structures, advancing early warning technologies such as seabed sensors and coastal radar systems, and enhancing disaster literacy through public education and scenario-based training. By adopting a science- and technology-driven approach, Indonesia can strengthen its resilience and reduce vulnerability among coastal populations facing future tsunami threats.

Mining with an open pit system is carried out by excavating and removing the overburden to obtain coal. However, before mining, it is important to obtain geotechnical data information. As well as the lithology of the rocks below the surface, it is necessary to carry out geotechnical drilling (full coring). This study can determine the value of slope geometry safety factors and plan safe slope geometry, both individual slopes and overall slopes. Therefore, this was done to determine the influence of GSI geotechnical parameters on the value of static and dynamic slope safety factors. The method used in determining the safety factor and the probability of an avalanche is the Morgenstern-Price boundary equilibrium method with the Generalized Hoek-Brown collapse criterion in static and dynamic slope conditions. The input parameters used in the analysis were natural density, compressive strength value (UCS), geological srength index (GSI), disturbance factor (D), intact rock constant (mi), as well as seismic load factor, and groundwater level. The optimal geometry on the Highwall slope is the configuration of the Highwall slope with a height of 74 m and an angle of 23°, supported by a single slope of 5-10 meters, a berm of 7 meters with an angle of 40°. Seam D Claystone lithology with GSI 50, Siltstone with GSI 70, Sandstone with GSI 70, and Seam E Claystone lithology with GSI 50, Siltstone with GSI 40, Sandstone with GSI 75.Can be applied within a safe limit where FK Static 1.7 PK Static 0% and FK Dynamic 1.4 PK Dynamic 6%.

The study aims to analyze the occupational safety and environmental health risks due to aircraft painting at the Hangar of PT. XYZ. The study is a descriptive study with a qualitative approach. The results of the study are the analysis of occupational safety risks seen from occupational safety risks and risk control. Occupational safety risks in aircraft painting activities at PT. XYZ are divided into several parts, namely (1) Exposure to hazardous chemicals is included in the high category; (2) The risk of work accidents is included in the moderate category; (3) Equipment damage is included in the low category; and (4) Fire is included in the low category. Risk control can be carried out by (1) Increasing strict supervision of the aircraft painting process; (2) Conducting appropriate occupational safety training for workers; (3) Using PPE; (4) Using adequate safety equipment; and (5) Carrying out proper equipment maintenance. The analysis of environmental health risks is seen from environmental health risks, sources of risk and risk control. Environmental health risks are divided into several parts, namely (1) Air pollution is included in the moderate category; (2) Soil and water contamination is included in the moderate category; and (3) Environmental damage is included in the moderate category. Sources of environmental health risks are the use of hazardous chemicals and painting waste. Risk control can be done by carrying out strict supervision, using safe chemicals and proper waste management.

The Jelekong landfill was a temporary landfill site following a landslide at the Leuwigajah landfill. TPA Jelekong was officially closed at the end of 2005 because it was no longer able to accommodate the increasing volume of waste. However, the impact of activities from the former landfill still has the potential to pollute the environment, especially groundwater sources. The research aimed to identify the physical and chemical parameters of water in the Jelekong ex-landfill case study area and the surrounding area, and to compare the physical and chemical parameters of water between the Jelekong ex-landfill and the landfill that is still operating (Sarimukti landfill). Data were obtained from 4 water sample points and tested using several test methods, namely Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Ion Chromatography (IC), alkalinity, and stable water isotopes. The results showed that the physical characteristics of the Jelekong area generally have a neutral pH with one point having an alkaline pH (JL-02) due to interaction with andesite lithology and the highest DO concentration at point JL-02. While the Sarimukti landfill has a pH value of 7.89-8.27 indicating the result of high bicarbonate concentrations, the TDS value of 15700-18200 ppm indicates the large number of ions and solutes derived from organic and inorganic waste. Piper diagrams show two water facies in the Jelekong area, Ca-HCO3 and Na-HCO3. Sample JL-03 indicates a mixture with landfill leachate due to high Cl and SO4 concentrations. Sample JL-01 still indicates leachate because when compared to the sarimukti sample, the Cl and SO4 concentrations are still quite high indicating a result of both organic and inorganic waste. Stable isotope test results indicated that the water was derived from local precipitation.

Landslides or commonly called landslides are a disaster that often hits areas with tropical climates. The damage caused by landslides is most dominantly structural damage such as damaged road sections that are cut off. At the research location, there was a landslide that resulted in the obstruction of the road flow which was originally two lanes to one lane, it is feared that landslides will occur again, so one of the landslide prevention techniques is to use retaining walls. Based on this, this study is deemed necessary to determine the slope safety factor and to determine the safety of the slope after using retaining walls. The purpose of this study was to determine the level of slope safety without being given a load, the level of slope safety after being given a load of 25 Kpa and the level of slope safety after being given a load of 25 kpa and the addition of a retaining wall on the research slope using a Retaining Wall. In this study using the Finite Element Method in the calculation to find the level of safety of a slope, the researcher used the help of Plaxis 2D V20 Software, and the results of the calculation obtained a slope safety factor of 1.31, after being given a load of 25 kpa the slope safety factor was 1.14 and after being given a retaining wall the slope safety factor increased to 2.46.

Land cover change has a significant impact on the hydrology of watershed areas, including increasing flood risk. This study aims to analyze land cover changes in the Siborgonyi and Acai sub-watersheds between 2013 and 2022 and their impact on flood potential. The methods used include spatial analysis with GIS, flood modeling using HEC-RAS, and Curve Number (CN) calculations to identify changes in soil infiltration capacity. The results show that land cover changes have a substantial effect on the increase in flood risk. The reduction of forest areas and the expansion of built-up land indicate a large-scale conversion of natural vegetation into residential and infrastructure areas. CN values in 2022 increased across most areas, indicating reduced soil infiltration capacity and increased surface runoff. Flood modeling shows that both the extent and depth of inundation significantly increased in 2022, particularly in downstream areas with basin-like topography.

Automatic Identification System (AIS) is a communication technology that plays an important role in improving operational safety and efficiency in the shipping industry. AIS allows ships to exchange real-time data on identity, position, speed, and direction, which helps prevent collisions and facilitates maritime traffic management by port authorities. In addition, AIS functions in search and rescue operations by providing accurate information on the location of ships in trouble. In terms of security, AIS allows monitoring of suspicious ships, thus helping in preventing illegal activities in the waters. This study aims to design and develop a prototype AIS receiver based on LoRa, Arduino, and LCD HMI. The LoRa module was chosen because of its ability to transmit data over long distances with low power consumption, which is suitable for the maritime environment. Arduino is used as the main microcontroller to control the system, while the LCD HMI serves as the display interface for the received data. After the hardware and software design was completed, the system was tested through functional testing and performance measurements using a spectrum analyzer to evaluate the strength of the LoRa signal at various distances. The test results show that the AIS receiver is able to receive data well up to 15 meters on land and 13 meters at sea, with a delay of 100 milliseconds. System performance degrades at longer distances due to environmental interference and signal attenuation. These findings provide insight into the effective limits of LoRa communication in maritime applications and can be used as a reference for frequency testing and optimization of LoRa-based long-range communication systems.

Research aims to design and develop a boiler system for heating Marine Fuel Oil (MFO) 180 CST by integrating Internet of Things (IoT) technology to enhance efficiency and operational monitoring. The methods used include boiler system design, selection of types and materials according to international standards, and the implementation of an optimal combustion system. IoT sensors are strategically placed to monitor key parameters such as temperature, pressure, and fluid flow in real-time. The collected data is transmitted to a cloud platform, enabling remote monitoring and automated performance analysis through a web or mobile-based application.. The research results indicate that IoT integration in the boiler system improves fuel heating efficiency, optimizes energy consumption, and facilitates easier monitoring and process control. Testing includes pressure tests, combustion efficiency, steam capacity, and material durability, with real-time monitoring to support performance analysis and early problem detection. Operational data evaluation allows for design adjustments or system settings to further enhance energy efficiency. With this innovation, the boiler system can operate more optimally, support energy efficiency, and facilitate predictive maintenance for sustainable industrial operations. The implementation of IoT in this system is expected to improve safety, effectiveness, and automation in boiler management, making it a more reliable and modern solution.

One of the negative impacts of the mining process is acid mine drainage which is formed from the oxidation of minerals containing iron sulfur, such as pyrite (FeS2) and pyrothite (FeS) by oxidizers such as water and oxygen. To handle or control acid mine drainage, one way is to use activated carbon or often referred to as activated charcoal, which is a type of carbon that has a very large surface area. Charcoal is a porous solid that contains 85% to 95% carbon, produced from materials containing carbon by heating at high temperatures without oxygen (pyrolysis). Activated carbon made from palm shells is an adsorbent that can be used to treat coal mine acid water, so that the water meets standards for flowing into the environment. This study used concentration variants of 4 grams, 6 grams, 8 grams and contact times of 30 minutes, 60 minutes and 150 minutes. The results of this study show that the concentration of palm oil shell activated carbon adsorbent influences the reduction of iron (Fe) and manganese (Mn) metal levels as well as the pH conditions in acid mine drainage water. The higher the concentration and the longer the contact time, the more heavy metals are adsorbed, the contact time is the highest. The optimal concentration in this study was 150 minutes and the optimal concentration was 8 grams with physical activation.