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All Journal Jurnal Ilmu Dasar MAJALAH ILMIAH GLOBE Computational and Experimental Research in Materials and Renewable Energy (CERiMRE)
Sa’adah, Umi
Unknown Affiliation
Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Education Energy Materials Science & Nanotechnology Mathematics Physics

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Comparative Analytic of Viscoelasticity Carbon, Glass, and Graphite Fiber Composite Using Maxwell Model Khohar, Ro’sil; Sa’adah, Umi; Puspita, Dewi Azzahra
Computational And Experimental Research In Materials And Renewable Energy Vol 1 No 1 (2018): November
Publisher : Physics Department, Faculty of Mathematics and Natural Sciences, University of Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/cerimre.v1i1.19545

Abstract

The fulfillment of the need for materials with viscoelastic characteristics to be a supporting factor. The aim is to obtain composite materials with good viscoelasticity. Vinylester matrix composite materials with variations of graphite, glass, and carbon fibers were tested using FEA and Maxwell model. The simulated viscoelasticity of the isotropic, transverse, and mixed state of glass, carbon, and graphite fibers depends on the magnitude of modulus Young and Poisson's ratio. The most significant sequence value of viscoelasticity is in graphite fiber 10,4 GPa, carbon 5,5 GPa fiber, and glass fiber 3,78 GPa.
PEMODELAN DISTRIBUSI SPASIAL KASUS POSITIF COVID-19 MENGGUNAKAN ALGORITMA GEOGRAPHICALLY WEIGHTED REGRESSION (GWR) Studi Kasus Provinsi DKI Jakarta: (Modeling Spatially Distribution of COVID-19 using Geographically Weighted Regression (GWR) Case Study DKI Jakarta Province) Ali, Abdullah; Umam, Iddam Hairuly; Mannesa, Masita Dwi Mandini; Sa’adah, Umi
Majalah Ilmiah Globe Vol. 24 No. 1 (2022): GLOBE VOL 24 NO 1 TAHUN 2022
Publisher : Badan Informasi Geospasial

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Abstract

Wabah novel corona virus 2019 (Covid-19) yang pertama kali ditemukan di Wuhan, China menjadi sebuah pandemi global yang berdampak sangat signifikan terhadap seluruh aspek kehidupan. Kasus positif Covid-19 di Indonesia pertama kali terkonfirmasi pada tanggal 2 Maret 2020 di Provinsi DKI Jakarta yang kemudian ditetapkan sebagai episentrum transmisi Covid-19 di Indonesia. Berbagai penelitian dilakukan untuk melakukan upaya mitigasi, mengetahui dampak dan penyebab, hingga investigasi berberapa faktor yang sangat terkait dengan transmisi Covid-19. Distribusi kasus positif Covid-19 sangat terkait dengan lokasi, sehingga salah satu algoritma yang tepat untuk melakukan investigasi adalah model Geographically Weighted Regression (GWR). Model GWR merupakan pengembangan dari model regresi global dimana nilai bobot variabel prediktor dihitung pada setiap lokasi pengamatan. Penelitian ini bertujuan untuk memodelkan distribusi spasial kasus positif Covid-19 menggunakan model GWR dengan fungsi Kernel Adaptif Bisquare. Variabel prediktor yang ditentukan melalui studi literatur adalah tingkat kepadatan penduduk, jumlah fasilitas kesehatan, dan kelompok usia rentan. Pemilihan rentang kelompok usia rentan dilakukan menggunakan algoritma Lasso-Cross Validation (Lasso-CV). Hasil model GWR menunjukkan koefisien determinasi sebesar 0,908 yang artinya 90,8% kasus positif Covid-19 di DKI Jakarta dipengaruhi oleh variabel yang digunakan, sedangkan 9,2% kasus positif Covid-19 dipengaruhi oleh faktor lain di luar penelitian. Wilayah dengan koefisien determinasi tertinggi terdapat pada wilayah Jakarta Utara bagian barat, Jakarta Barat bagian utara, dan Jakarta Timur, sedangkan nilai koefisien determinasi terendah terdapat pada wilayah Jakarta Pusat.
Molecular Dynamics Study for Inhibition of Iron Corrosion in High-Temperature Liquid PbBi with Nobel Gas Inhibitors Sa’adah, Umi; Arkundato, Artoto; Rohman, Lutfi
Jurnal ILMU DASAR Vol 17 No 2 (2016)
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1057.906 KB) | DOI: 10.19184/jid.v17i2.2690

Abstract

Molecular dynamics is a popular method to observe the movement of interacting molecules. In this study molecular dynamics method was used to observe the phenomenon of iron corrosion and analyze effect of noble gases as a corrosion inhibitor for iron in liquid metal PbBi. Physical quantities are evaluated from the results of this study including: Mean Square Displacement (MSD), the diffusion coefficient, and for the crystal structure is visualized using Ovito program. The ron is placed in the middle high temperature liquid PbBi, the noble gases is injected into the liquid metal. Based on the three kinds of the noble gases (helium, neon, and argon) thhat injected into the molten metal PbBi, it obtained that Argon is the most effective in inhibiting the corrosion of iron. Argon is able to reduce the corrosion rate of 80.29% iron for temperature of 1023K. One reason to use the noble gas because these gases are difficult to react with other elements. Keywords: Molecular Dynamics, Corrosion in Liquid metals, Nobel Gases, Inhibitors
Co-Authors Ali, Abdullah Artoto Arkundato Khohar, Ro’sil Lutfi Rohman Mannesa, Masita Dwi Mandini Puspita, Dewi Azzahra Umam, Iddam Hairuly