Calamity: A Journal of Disaster Technology and Engineering
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Handling of area impact of land exploitation in the Kendeng Mountain, Pati District, Central Java
Get PDFThe Kendeng Mountains are the largest limestone producer on the island of Java, so mining or over-exploitation is often carried out in several locations. Pati Regency is a city affected by the exploitation of the Kendeng Mountains, in addition to Rembang Regency. The northern Kendeng area, which is in southern Pati, has experienced more than 60% deforestation. The impacts of this exploitation are floods, droughts, and landslides in the South Pati region. Since 2019 the southern Pati region has experienced quite large flash floods approximately 5 times. To deal with the impact of exploitation this research uses analysis and synthesis methods. The clearing of forest land use as an agricultural and mining area in this location continued to occur from 1996 to 2016, and the rainfall that experienced the La Nina phenomenon in 2020/2021 caused flooding in the Tambakromo, Kayen, Sukolilo, and Winong areas. and drought in 30 villages, in the Pati region, Central Java. To maintain the impact of exploitation, reforestation must be carried out, construction of drainage canals, and construction of spring
Visualizing 2018 lombok earthquake in Indonesia using crowdsouring data: How people experience it
Get PDFAlong with the development of science and technology, using big data, map makers can take advantage of crowdsourcing social media data on Twitter to obtain user location when uploading tweets, which can be called geolocated tweets. Earthquakes that occur very often in Indonesia often grab people's attention, especially netizens who use social media like Twitter. One of the major earthquakes that occurred in Indonesia in 2018 was the Lombok earthquake, which occurred twice in a row from July to August 2018. Using Twitter data, information and social responses related to the 2018 Lombok earthquake can be obtained, which can be used as evaluation material for public handling and responding. The information is then visualized in various forms, and one of the best visualization methods is selected.This study uses Twint package in Python as a way of obtaining location data from Twitter. The method used to collect Twitter data is a case study on the social impact of the Lombok earthquake in Indonesia in 2018. The data observation method used is a simulation of several types of map visualization and survey methods in selecting the best type of visualization. The method of analysis used is by mapping the data on the number of tweets as the main object using various types of maps, as well as calculating survey results by scoring each group of questions.The results of spatial data extraction from Twitter in this study obtained 2032 tweets that had been selected and cleaned from 11,584 tweets. Map visualization with the theme of the social impact of the Lombok earthquake in 2018 was compiled using five types of visualization, namely choropleth maps, proportional symbol maps, dot maps, hexagonal tessellation maps, and heat maps. Based on the results of the survey on selecting the best visualization, it was found that the choropleth map is the best visualization method according to respondents with a cartography background and respondents who are unfamiliar with cartography because the information displayed is easier to read and understand
Failure analysis of pulverizer pipe elbow in PLTU boiler
Get PDFoai:ojs2.journal-iasssf.com:article/44Erosion occurs due to several different mechanisms, depending on the composition, size, shape of the eroding particles, speed, angle of impact, and surface composition of the eroded components. The pulverizer pipe elbow has become worn out due to the pulverized coal fluid abrasion flowing on the pipe, which the type is AISI Grade 1026. This study was carried out on the causes of this damage case. Damage to the elbow in the boiler needs to be analyzed for the failure of the elbow so that the damage's cause is known and it becomes a lesson so that the same damage does not occur again. The research aims to: 1. Find out the cause of damage to the pulverizer elbow on the boiler; 2. Know the correct maintenance strategy to increase the reliability of pulverizer pipes in boilers; 3. Simulate erosion due to coal particles in the pulverizer pipe using the Autodesk Simulation Computational Fluid Dynamics software program; 4. Analytical calculations of the erosion rate that occurs at the bend of the pulverizer pipe (elbow) in the boiler. The analysis was done by visual observation, hardness testing, metallographic observation, simulation of the ANSYS CFD program, and analytical calculation. The result of the ANSYS simulation showed that the main factor causing the leakage was erosion-corrosion. In the leaking area, the corrosion concentration was higher than in other areas, indicated by the red color in that area. From the calculation results, it was concluded that the largest erosion rate occurs at the angle of 200 with the value is 4.9548 x 10- 11 m3 / s, the smaller the pulverized coal’s angle of impact crashed the pulverizer pipe elbow, the greater the erosion