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All Journal Majalah Kulit, Karet, dan Plastik Malikussaleh Journal of Mathematics Learning (MJML) INVENTORY : Industrial Vocational E-Journal On Agroindustry
Irfan Rusmar
Politeknik Teknologi Kimia Industri Medan
Control & Systems Engineering Education Engineering Industrial & Manufacturing Engineering Mathematics Social Sciences

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Karakteristik plastik biodegradable dari limbah polipropilena dan pati tandan kosong kelapa sawit melalui metode pencampuran kering Elda Pelita; Tengku Rachmi Hidayani; Risma Sari; Irfan Rusmar; Trisna Yuniarti
Majalah Kulit, Karet, dan Plastik Vol 36, No 2 (2020): Majalah Kulit, Karet, dan Plastik
Publisher : Center for Leather, Rubber, and Plastic Ministry of Industry, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20543/mkkp.v36i2.5841

Abstract

Pemanfaatan limbah plastik polipropilena dan tandan kosong kelapa sawit dilakukan dengan cara mengolah serta menggabungkan limbah plastik polipropilena dengan pati tandan kosong sawit menjadi plastik biodegradable yang mudah terurai di alam. Modifikasi komposisi yang digunakan pada pembuatan plastik biodegradable adalah limbah plastik dan pati tandan kosong sawit adalah (80:20; 70:30; 60:40). Metode pencetakan plastik biodegradable adalah dengan metode kempa tekan panas. Hasil karakterisasi plastik biodegradable dengan komposisi optimum yaitu pada perbandingan 60:40 menunjukkan harga kekuatan tarik 6,54 N/m2 dan kemuluran 2,42%. Hasil analisa sifat biodegradable-nya didapatkan penurunan massa yang telah ditanam selama 1 bulan yaitu pada tanah sampah sebesar 6,78% dan analisa dengan FT-IR ditemukan bilangan gelombang 1165 cm-1 yang menunjukkan gugus fungsi C-O bending yang khas untuk menunjukkan ikatan antara limbah plastik polipropilena ter-grafting maleat anhidrida dan pati yang didukung dengan bilangan gelombang 1590-1560 cm-1 yang menunjukkan gugus fungsi C=C pada maleat anhidrida dan polipropilena yang terikat silang.
Correlation between Students' Mathematical and Logical Spatial Intelligence in Terms of Understanding Concepts M Zaiyar; Irfan Rusmar; Trisna Yuniarti
Malikussaleh Journal of Mathematics Learning (MJML) Vol 3, No 2 (2020): October
Publisher : Universitas Malikussaleh, Aceh Utara, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29103/mjml.v3i2.3005

Abstract

This study aims to determine the relationship of junior high school students’ spatial and mathematical logical intelligence based on understanding the concepts. Spatial intelligence indicators in this study are reviewed from students’ abilities in using images as a tool for solving problems, connecting data with concepts that have been held, and finding patterns in solving problems. On the other hand, the indicators of students’ mathematical logical intelligence is observed by looking at students' abilities to mention and understand information that is known in a problem, to draw up a plan of completion and to do mathematical calculations correctly. The indicators of understanding concepts are restating a concept, providing examples and non-examples of concepts, and applying concepts or algorithms in problem solving. The research method in this research is the Ex Post Facto correlational type, with using a purposive sampling as the sampling technique. The results of the data analysis obtained a correlation coefficient is around 0.93 with 86% R square. The relationship between the spatial intelligence variables is shown by the understanding of concepts by 86%, the level of the relationship, with the correlation coefficient is 0.93, where mathematical logical intelligence with an understanding of 80%, with the level of the relationship of 0.89, and the relationship of spatial intelligence with a mathematical logical is described by a 77% level of the relationship, with 0.88, as the correlation coefficient. The results showed that there was a very strong relationship between spatial intelligence and logical mathematics in terms of understanding students' concepts.
Komparasi Metode Regresi Linier, Exponential Smoothing dan ARIMA Pada Peramalan Volume Ekspor Minyak Kelapa Sawit di Indonesia Trisna Yuniarti; Juli Astuti; Irfan Rusmar; Ika Widiana; Fajar Ciputra Daeng Bani
INVENTORY: Industrial Vocational E-Journal On Agroindustry Vol 3, No 1 (2022): Published in June 2022
Publisher : Politeknik ATI Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52759/inventory.v3i1.74

Abstract

This study aims to compare several methods to get the best methods on forecasting the volume of Indonesian palm oil exports. In addition, this study also aims to estimate the volume of Indonesian palm oil exports for the next five years. Some of the forecasting methods used in this study are linear regression, exponential smoothing, and ARIMA. The data used is historical data on the volume of palm oil exports from 1981 to 2020. The results of calculations and analysis show that the exponential smoothing model of the damped trend method produces the smallest error value compared to other methods, the MAD value is 860,353, the MSE value is 1,707,738,707,222, the RSME value is 1,306,805, and the MAPE value is 20.6%. This method has chosen to be the best forecasting method for the next five years. The forecast results obtained that the volume of Indonesian palm oil exports for the next five years are28.864.223,31 tons, 28.967.062,92 tons, 29.064.976,80 tons, 29.158.200,89 tons, and 29.246.959,81 tons.
Co-Authors Elda Pelita Fajar Ciputra Daeng Bani Ika Widiana Juli Astuti M Zaiyar Risma Sari Tengku Rachmi Hidayani Trisna Yuniarti