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All Journal Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Jurnal Meteorologi Klimatologi dan Geofisika Artikulasi : Jurnal Pendidikan
Rizki Wulandari
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Astronomy Earth & Planetary Sciences Environmental Science Languange, Linguistic, Communication & Media Mathematics Physics Other

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ANALISIS PERGERAKAN DAN AKUMULASI COULOMB STRESS GEMPA UTAMA LOMBOK SELAMA TAHUN 2018 DAN PENGARUHNYA TERHADAP AKTIVITAS GUNUNG RINJANI Lasroha Marulitua Panjaitan; Erlangga Ibrahim Fattah; Cahli Suhendi; Rizki Wulandari; Hana Yudi Perkasa
Jurnal Meteorologi Klimatologi dan Geofisika Vol 7 No 1 (2020): Jurnal Meteorologi Klimatologi dan Geofisika
Publisher : Unit Penelitian dan Pengabdian Masyarakat Sekolah Tinggi Meteorologi Klimatologi dan Geofisika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36754/jmkg.v7i1.215

Abstract

Mechanically, earthquakes can be triggered by changes in static and dynamic stress. In terms of static stress change, it occurs when earthquake energy is released which then changes the stress conditions around the fault (for example at the end of the fault). The process of changing static stress in an area will cause seismic activity to occur in the surrounding area and in other areas with a great distance. The amount of change in Coulomb Failure stress (∆CFS) is quantifiable and has proven to be a powerful tool in explaining the movement and accumulation of stress caused by the mainshock and its aftershock. This study was conducted to calculate the distribution of stress changes due to the main Lombok earthquake (Mw≥6) during 2018 and its effect on Mount Rinjani activity, using the Coulomb 3.3 software. The earthquake data used were taken from the earthquake catalog of Global Centroid Moment Tensor (GCMT), International Seismological Center (ISC) and United States Geological Survey (USGS). The lateral difference in the value of ∆CFS shows the movement of energy from the main earthquake that triggered another earthquake as shown by the aftershock data. The results of this analysis of the movement and accumulation of ∆CFS will be used to identify the correlation with the activity of Mount Rinjani.
OPTIMALISASI pH PRODUKSI SELULASE DARI BAKTERI ENDOFITIK Pseudomonas stutzeri LBKURCC53, Pseudomonas stutzeri LBKURCC54, dan Actinobacter antratus LBKURCC60 Rizki Wulandari; Silvera Devi; Andi Dahliaty
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 2, No 1 (2015): Wisuda Februari 2015
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Abstract

Cellulase is an enzyme that can hydrolyze the β-1,4 bonds on cellulose and productionof glucose so that the enzyme is widely used in various industries. Cellulose enzymes can be produced by microorganism such as endophytic bacteria (LBKURCC53, LBKURCC54, and LBKURCC60). The activity of cellulase enzyme was determined by measuring the glucose produced using Nelson-Somogyi method. The optimum activity of cellulase enzyme from theisolates of LBKURCC53, LBKURCC54, and LBKURCC60 we measured at different pH. The enzyme of LBKURCC53 isolate was optimum at pH 7 with enzyme activity of 11,31 ± 1,69 x 10 -3 U/mL. While the enzyme of LBKURCC54 and LBKURCC60 isolates were optimum at pH 6,5 with enzyme activity 14,44 ± 2,94 x 10 -3 U/mL and 8,33 ± 1,11 x 10 -3 U/mL respectively. These comparison of cellulase enzyme activity of isolates LBKURCC53, LBKURCC54, and LBKURCC60 were determined by using Duncan multiple range test at 5% level (α≥0,05).
PENAKSIR RASIO REGRESI YANG EFISIEN UNTUK RATA-RATA POPULASI PADA SAMPLING ACAK SEDERHANA MENGGUNAKAN DUA KARAKTER TAMBAHAN Rizki Wulandari; Rustam Efendi; Haposan Sirait
Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam Vol 1, No 2 (2014): Wisuda Oktober 2014
Publisher : Jurnal Online Mahasiswa (JOM) Bidang Matematika dan Ilmu Pengetahuan Alam

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Abstract

Three regression ratio estimators are used to estimate the population mean Y under simple random sampling.  Using two auxiliary variables X and Z, it should be conditioned that there is high correlation between Y and X, Y and Z, whereas there mayor may not be any correlation between X dan Z.  These estimators are recommended by Singh, Upadhyaya and Premchandra [5] which is a review of the article “An Improved Version of Regression Ratio Estimator with Two Auxiliary Variables in Sample Surveys.”  All estimators are biased. The efficient estimator is one with the least Mean Square Error (MSE), determined by comparing each type of estimator.
Pengaruh Model Number Head Together Terhadap Kemampuan Menulis Teks Eksplanasi Siswa Kelas VIII SMP YPK Pematangsiantar Rizki Wulandari; Silitonga, Rahmat Kartolo
Artikulasi: Jurnal Pendidikan Vol. 4 No. 2 (2022): Artikulasi : Jurnal Pendidikan
Publisher : Program Studi Pendidikan Bahasa dan Sastra Indonesia FKIP Universitas Simalungun

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36985/sdxwrh24

Abstract

Judul penelitian ini adalah Pengaruh Model Number Head Together Terhadap Kemampuan Menulis Teks Eksplanasi SiswaKelas VIII SMP YPK Pematangsiantar. Tujuan penelitian ini adalah untuk menjelaskan Korelasi Penerapan Model Number Head Together Terhadap Kemampuan Menulis Teks Eksplanasi Siswa Kelas Kelas VIII SMP YPK Pematangsiantar. Penelitian ini menggunakan pendekatan kuantitatif dengan metode korelasional. Teknik Pengumpulan data penelitian ini berbentuk essay test.Teknik pengolahan data menggunakan program SPSS versi 22. Analisis data dilakukan dengan cara uji product moment, uji t regresi linear sederhana, mencari rata-rata (X) dan (Y), standar deviasi (S), dan hipotesis diuji dengan statistik atau uji t pada taraf signifikan = 0,05. Nilai rata-rata pre-test dan post-test adalah 62,72 dan 88,50. Dari hasil uji hipotesis menggunakan uji t diperoleh thitung 3,415 > ttabel 2,00 yang menunjukkan bahwa Hₐ diterima dan H₀ ditolak. Jadi, ada pengaruh penggunaan model Number Head Together terhadap kemampuan menulis teks eksplanasi. Diperoleh hasil bahwa Kemmapuan menulis tek eksplanasi peserta didik meningkat dengan menggunakan model pembelajaran Number Head Together
Co-Authors Andi Dahliaty Erlangga Ibrahim Fattah Hana Yudi Perkasa Haposan Sirait Lasroha Marulitua Panjaitan Rustam Efendi SILITONGA, RAHMAT KARTOLO Silvera Devi Suhendi, Cahli