Dera, Nurmala Santi
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SIFAT FISIK MATERIAL PAPAN KOMPOSITE BERBAHAN SERAT TEBU DENGAN MATRIX RESIN POLYESTER Dera, Nurmala Santi; Kilo, Faisal; Talango, Novriyanti; Ishak, Sahional; Lestari, Wahyu Dwi
JURNAL ILMIAH MOMENTUM Vol 19, No 2 (2023)
Publisher : Universitas Wahid Hasyim

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36499/jim.v19i2.9836

Abstract

Sugar cane fiber is an organic waste mostly produced by sugar factories in Indonesia such as in Gorontalo Province. If it is properly processed, it will have high economic value and will help the community’s economy during Covid 19 pandemic. This fiber, however, is easy to find, and it is not dangerous for human health. The important thing is that this fiber can be degraded naturally. Hence it can be used as composite reinforcing fiber which can help overcome environment problems. This study aimed at investigating the physical characteristics of natural fiber composite-based new material with characteristics and structures which can be used for automotive industry. The method applied in this study was by doing physical test such as density, water content, water absorption level, and thickness development with random-pattern treatments consisting of fraction variations of sugar cane fiber volumes of 10%, 30%, and 50% and fraction variations of resin volumes of 90%, 80%, and 70%. Each treatment consisted of 3 specimens with determined size, and they were tested in laboratory in order to find out the physical. Findings revealed that the highest density was in specimen 3 with fiber volume of 50% and resin volume of 70%, and the average value was 1.162 g/cm3. Meanwhile, the highest water content was specimen 1 with fiber volume of 10% and resin volume of 90% obtaining value of 0.51%. The water absorption level during 24 hours that obtained maximal result and value of 6.89% was specimen 2 with fiber volume of 30% and resin volume of 80%. The result for thickness development during 24 hours that obtained value of 10% was specimen 1 with fiber volume of 10% and resin volume of 90%. If it is validated with Indonesian National Standard, some of physical test results should be further formulated to get result based on Indonesian National Standard. Regarding the explanation, the fiber volume and resin volume fractions highly influenced the natural fiber (sugar cane fiber) composite-based new material making and it can be used for automotive industry.
Variasi Kemiringan Sudut Pengelasan SMAW terhadap Sifat Mekanis Material Baja SS400 Dera, Nurmala Santi; Saputro, Onesimus Kevin; Boli, Rahmad Hidayat
JURNAL ILMIAH MOMENTUM Vol 20, No 2 (2024): Vol 20, No 2
Publisher : Universitas Wahid Hasyim

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36499/jim.v20i2.12548

Abstract

Pengembangan teknologi di bidang konstruksi yang semakin maju tidak dapat dipisahkan dari pengelasan karena mempunyai peranan yang sangat penting. Tujuan penelitian ini adalah untuk mengetahui pengaruh variasi kemiringan elektroda pada pengelasan SMAW terhadap sifat mekanis baja SS400. Metode yang digunakan dalam penelitian ini adalah dengan melakukan pengujian eksperimen di laboratorium. Penelitian ini memvariasikan kemiringan elektroda yaitu 30°,45° dan 60° menggunakan mesin las SMAW (Shielded Metal Arc Welding) adapun hasil penelitian yaitu Nilai tegangan sudut kemiringan elektroda 30° σ =376,5 MPa, 45° σ = 382,90 MPa ,60° σ =411,9 MPa, nilai rata-rata regangan e=16,67 % dan nilai rata-rata modulus elastisitas yang tinggi terdapat pada pengelasan 30° dengan nilai σ=140.053 MPa. Tegangan dan regangan sangat dipengaruhi oleh sudut kemiringan elektroda karena terkait dengan distribusi panas dan penetrasi las
PENGARUH PACK CARBURIZING ARANG ENCENG GONDOK TERHADAP LAJU KOROSI CAST IRON ALAT TURBOCHARGER Dera, Nurmala Santi; Indrawan , Indrawan Laria; Novriyanti , Novriyanti Talango; Sahional , Sahional Ishak
JURNAL ILMIAH MOMENTUM Vol 21 No 1 (2025): April
Publisher : Universitas Wahid Hasyim

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36499/jim.v21i1.12668

Abstract

Corrosion resistance is a crucial factor in extending the service life of cast iron turbocharger components, particularly in corrosive environments. One effective approach to enhance corrosion resistance is through the pack carburizing process, which forms a protective carbon layer on the material’s surface. In this study, water hyacinth charcoal was utilized as an alternative carbon source due to its environmentally friendly and economical characteristics. The research aimed to evaluate the effect of varying pack carburizing durations on the corrosion resistance of cast iron turbochargers and to characterize the macrostructural changes on the surface resulting from the treatment. The methodology involved a pack carburizing process with holding times of 2, 4, and 6 hours at a controlled temperature, followed by electrochemical corrosion testing. Macrostructural characterization was also conducted to observe surface morphology changes due to carbon diffusion. The test results showed that the untreated specimen had a corrosion rate of 0.180 mm/y, which decreased to 0.120 mm/y after 2 hours of carburizing. A more significant reduction was observed in the 4-hour specimen, with a corrosion rate of 0.095 mm/y, representing a 47% decrease compared to the untreated sample. However, after 6 hours, the corrosion rate only slightly decreased to 0.090 mm/y, indicating that the carbon layer had reached saturation. Macrostructural observations confirmed the formation of a more homogeneous carbon layer in the 4-hour specimen, while the 6-hour specimen exhibited a thicker layer with diminishing protective effectiveness. This study demonstrates that pack carburizing using water hyacinth charcoal can significantly enhance the corrosion resistance of cast iron turbochargers, with an optimal treatment duration of 4 hours for maximum protection. Keywords: pack carburizing, water hyacinth charcoal, cast iron, corrosion resistance, mechanical properties