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PENENTUAN SIFAT KRISTALINITAS SERBUK PARTIKEL OKSIDA BESI BERBASIS PASIR ALAM LOGAS MENGGUNAKAN DIFRAKSI SINAR-X
(Elfitra, 2024-01) Firdaus, Miftahul Haqie Al
Telah dilakukan penelitian mengenai sifat kristalinitas serbuk partikel oksida besi berbasis pasir alam Logas. Pasir alam diambil di desa Logas yang kemudian dibawa ke Laboratorium Instrumentasi dan Kemagnetan Universitas Riau untuk dipisahkan antara oksida besi dengan non-oksida besi menggunakan magnet kuat Neodymium Iron Boron (NdFeB). Kemudian sampel pasir alam ini diproses menggunakan ball milling 4 tahap dengan total waktu 200 jam, dimana setiap tahapan, produknya dipisahkan antara oksida besi dan non oksida besi menggunakan magnet kuat Neodymium Iron Boron (NdFeB). Sampel produk akhir dari tahap 4 dari ball milling ini dibagi menjadi 5 bagian yang sama beratnya lalu kemudian didoping menggunakan nikel dengan konsentrasi 0wt.%, 1wt.%, 2wt.%, 3wt.%, dan 4wt.% dan di ball milling selama 20 jam. Sampel ini dinamakan dengan BM5A, BM5B, BM5C, BM5D, dan BM5E. Selanjutnya sampel-sampel ini ditentukan sifat kristalisasinya menggunakan metode difraksi sinar-X (XRD). Hasil uji XRD menunjukkan bahwa sampel serbuk partikel oksida besi memiliki fase hematit dengan struktur rhombohedral dan ukuran rata-rata partikel yang mengecil seiring bertambahnya konsentrasi dopingan nikel.
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SINTESIS SENYAWA 4-(1-(4-FLUOROFENIL)-5-(3-METOKSIFENIL)- 4,5-DIHIDRO-1H-PIRAZOL-3-IL) FENOL
(Elfitra, 2024-01) Kurniati, Maya; Jasril, Jasril
Pyrazoline has two nitrogen atoms adjacent to each other in its ring and possess only one endocyclic double bond. The pyrazoline compound 4-(1-(4-Fluorophenyl)-5-(3- Methoxyphenyl)-4,5-Dihydro-1H-Pirazol-3-yl) phenol and named as P3OME-4OH-4F has been successfully synthesized through three stages reaction. The first stage is the formation of the chalcone compound through the Claisen-Schmidt condensation reaction with a yield of 54%, the second stage is the formation of the hydrazine compound through diazotation and reduction reactions with a yield of 84% and the final stage is the formation of the P3OME-4OH-4F compound through a cyclization reaction with a yield obtained of 52%. The purity of the compound was tested by measuring the melting point, TLC and HPLC analysis. The structure of the P3OME-4OH-4F compound was confirmed by characterization using UV spectroscopy and FTIR.
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PERAMALAN HARGA GABAH DAN BERAS BULANAN DI INDONESIA DENGAN METODE ARIMA DAN METODE HOLT-WINTERS
(Elfitra, 2024-01) Fadliansyah, Hery; Bustami, Bustami
The Autoregressive Integrated Moving Average (ARIMA) method is a method that combines Autoregressive and Moving Average forecasting models with differencing, generally expressed as ARIMA(𝑝, 𝑑, 𝑞). The Holt-Winters method or Triple Exponential Smoothing is a smoothing method based on three smoothing parameters, each element, namely α (level), β (trend smoothing), and γ (seasonal index). The ARIMA and Holt- Winters methods in this research are used for forecasting analysis of monthly prices of grain and rice in Indonesia with data for the period January 2013 to July 2022. The study shows that forecasting using the ARIMA method is better than the Holt-Winters method in this research based on accuracy values smaller RMSE
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PERAMALAN HARGA GABAH DAN BERAS BULANAN DI INDONESIA DENGAN METODE ARIMA DAN METODE HOLT-WINTERS
(Elfitra, 2024-01) Fadliansyah, Hery; Bustami, Bustami
The Autoregressive Integrated Moving Average (ARIMA) method is a method that combines Autoregressive and Moving Average forecasting models with differencing, generally expressed as ARIMA(𝑝, 𝑑, 𝑞). The Holt-Winters method or Triple Exponential Smoothing is a smoothing method based on three smoothing parameters, each element, namely α (level), β (trend smoothing), and γ (seasonal index). The ARIMA and Holt- Winters methods in this research are used for forecasting analysis of monthly prices of grain and rice in Indonesia with data for the period January 2013 to July 2022. The study shows that forecasting using the ARIMA method is better than the Holt-Winters method in this research based on accuracy values smaller RMSE
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IURAN NORMAL DANA PENSIUN MENGGUNAKAN METODE AGGREGATE COST DAN PROJECTED UNIT CREDIT BERDASARKAN DISTRIBUSI WEIBULL
(Elfitra, 2024-01) Yelni, Fitri Susrida
A worker really longs for guaranteed life in old age. A worker is not always in optimal condition. So a worker must have a plan from the start in order to guarantee future prosperity when entering retirement age. One of the solutions is by joining a pension fund program. The aim of this research is to determine the present value of pension benefits, normal contributions using two methods, namely the aggregate cost method and projected unit credit based on the Weibull distrubution. Weibull distribution parameter estimates are determined using the maximum likelihood estimation and then determined using the Newton-Raphson iteration method. The soluting to the problem is obtained by determining the initial lifetime annuity. Initial term life annuity, then the present value of pension benefits. Normal contributions using the Aggregate Cost method basade on the Weibull distribution are smaller than normal contributions using the Projected Unit Credit method basad on the weibull distribution.