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Pengelasan marupakan metode penyambungan material yang sering digunakan pada kapal dan industri lepas pantai. Baja karbon rendah seperti baja A36 dan baja structural steel 400 (SS400) merupakan material yang sering digunakan dalam konstruksi kapal. Pada penelitian ini akan dilakukan analisis pengaruh variasi heat input pada pengelasan SMAW sambungan pelat baja A36 dengan baja structural steel 400 (SS400) terhadap uji laju korosi dan beberapa sifat mekanik seperti uji impact dan uji metalografi. Untuk variasi yang digunakan pada penelitian ini adalah heat input yaitu 1,08 kJ/mm, 1,26 kJ/mm, dan 1,44 kJ/mm. Dari pengujian impact didapatkan untuk nilai ketangguhan impact energy terbesar yaitu pada variasi heat input 1,44 kJ/mm sebesar 122 Joule. Pada pengujian makro metalografi, didapatkan hasil bahwa semakin besar heat input yang digunakan maka akan memiliki ukuran weld metal yang semakin lebar. Selain itu pada pengujian mikro metalografi didapatkan bahwa semakin besar heat input yang digunakan maka struktur mikro yang terbentuk akan semakin kasar. Sehingga akan menyebabkan nilai ketangguhan meningkat. Sementara pada pengujian laju korosi, didapatkan bahwa nilai laju korosi tertinggi yaitu pada spesimen dengan variasi heat input 1,44 kJ/mm yaitu sebesar 0,5386 mm/a.

Mudflow disaster in Sidoarjo on May 29, 2006 have resulted in losses in various fields, whether social, economic, and ecological. One of the efforts to control the mud is mostly channeled to Porong river towards the sea in the Madura Strait. Mouth of the river is part of the coastal area that plays an important role in the economic, ecological, and also a region with a complex ecosystem. As a result of the disposal of sludge to the Estuary of Porong river this leads to changes in water quality, it therefore need for water quality modeling in order to identify it in accordance with the benchmarks of quality standards is allowed. A Hydrodynamic an d water quality model with Mike 21 Hydrodynamics and Ecolab module 1 are used to quantity and to find out the spreading of COD, TSS, phosphate, and nitrate. At high tide, currents in estuary Porong moving upstream, so the spread of water quality parameters will be small around the estuary. At low tide conditions the flow moves in the opposite direction so that the distribution of water quality parameters will be greater than the current at the river mouth. The condition of water quality parameters most significantly, the worth of 34 mg / L for COD, 14.46 mg / L for nitrate, 30 mg / L for TSS, and a phosphate worth to 0.43 mg / L.

⎯ Coronavirus belongs to the ARI (Acute Respiratory Infection) disease, which has a high level of mortality risk. In 2019, this virus was transformed into Covid-19 with a rapid spread and a more massive impact. This disease has become a worldwide pandemic. Indonesia is a developing country and is included as one of the most densely populated countries affected by the Covid-19 pandemic, which has great potential to fail in overcoming this problem. Approximately 60% of Indonesia's population lives in coastal areas with low levels of welfare in almost all sectors of life such as social, economic, education, and health. This study aims to analyze the level of community vulnerability in the coastal area of Surabaya City by using the Analytical Hierarchy Process method. From the data taken by the survey, the results of the exposure of the Bulak Banteng Village area of Surabaya in the health, socio-cultural, economic, and general fields are 0.0469, 0.0871, 0.1809, and 0.3551, respectively. So the overall vulnerability is 0.67, which is included in the medium vulnerability criteria.

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