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Simulasi Numerik untuk Pertumbuhan Retakan pada Bahan Heterogen: Studi Kasus pada Bitumen Aspal Sayahdin Alfat; Sudirman Sudirman
JRST (Jurnal Riset Sains dan Teknologi) Volume 4 No. 1 Maret 2020: JRST
Publisher : Universitas Muhammadiyah Purwokerto

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1102.197 KB) | DOI: 10.30595/jrst.v4i1.5938

Abstract

Penelitian ini bertujuan untuk menunjukkan perilaku pertumbuhan retakan pada perkerasan aspal menggunakan model Takaishi-Kimura dan mengetahui tingkat kerusakan oleh energi elastisitas dan permukaan. Penelitian ini, telah menggunakan persamaan pertumbuhan retakan yang dikembangkan oleh Takaishi dan Kimura. Penelitian ini menggunakan Adaptive Finite Element Method dan Phase Field Fase untuk mengamati perubahan elastisitas dan energi permukaan dan mengamati perilaku pertumbuhan retak. Penelitian ini telah menggunakan 3 jenis domain sebagai berikut; (1) Retakan yang berasal dari bitumen aspal ke agregat; (2) Retakan yang berasal dari agregat ke bitumen aspal; dan (3) Retakan pada material heterogen. Asumsi yang digunakan yaitu; (1) Material bersifat heterogen; (2) Material bersifat linear elastis; (3) Material bersifat isotropic, atau ????(????) = ????; (4) Pada kondisi awal tidak terjadi deformasi atau ????0(????) = 0; (5) Panjang retakan awal memenuhi persamaan: ????0(????) = ????(0,????) dan(6)????(????,????) = 0 atau diabaikan. Hasil penelitian menunjukkan ada pengaruh pertumbuhan retakan terhadap perubahan energi elastisitas dan permukaan pada material heterogen dan pola kelakuan retakan berbeda-beda setiap domain. Penelitian selanjutnya diharapkan melakukan penelitian mengenai factor-faktor penyebab retakan lainnya.
Microwave Assisted Extraction of Banana Stem Waste and its Antifungal Activity against Fusarium Oxysporum Mashuni Mashuni; muhammad Natsir; Sudirman Sudirman; Sitti Hadijah Sabarwati; Fitri Handayani Hamid; M. Jahiding
International Journal of Science Technology and Health Vol 1 No 1 (2023): Science Technology and Health
Publisher : LPPM ISTEK 'Aisyiyah Kendari

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Banana stem (BS) waste is obtained in large quantities in banana production. In this work, microwave extraction (MAE) from BS was used, and the solvent concentration parameters were 50%, 60%, 70%, 80%, 96% (v/v) ethanol, and 5% HCl with a sample weight of 10 g each. The influence of solvent, time, temperature, and solid: the liquid ratio was evaluated on the extraction results. Total phenolic content (TPC) and its functional performance against Fusarium oxysporum. The effect of a high ethanol concentration on BS extraction was observed because the higher ethanol solvent concentration resulted in higher extraction results and TPC. Optimal MAE conditions were determined at 200 watts for 20 minutes, with 80% ethanol showing better TPC results than other ethanol concentrations, namely 0.7171 mg g-1. The results of chemical content analysis using gas chromatography–mass spectrometry (GC-MS) of BS extract of 80% ethanol obtained phenolic compounds, carboxylic acids, aldehydes, esters, ketones, and furans. BS extract of 80% ethanol showed antifungal activity of Fusarium oxysporum with an apparent zone diameter of 9.7 mm (moderate category). It can be concluded that MAE is an efficient technique for releasing bioactive molecules from BS with TPC and antifungal applications in the agricultural industry.