Judul: Performance Test of Disc Mill Machine for Porang Flour
Abstrak: Tanaman porang merupakan salah satu komoditas yang melimpah sehingga berpeluang tinggi menjadi komoditi ekspor dalam bentuk umbi segar, chip kering, dan tepung. Tepung hasil penggilingan umbi porang memiliki harga jual yang lebih tinggi dibandingkan harga umbi porang segar. Hal tersebut menciptakan dorongan untuk usaha pengolahan sehingga dibutuhkan mesin penepungan umbi porang dengan kinerja penepungan yang baik. Mesin penepungan tipe disc mill merupakan salah satu mesin penepugan yang dapat mengolah porang hingga ukuran 60-80 mesh. Penelitian ini bertujuan untuk menganalisis dan menguji performansi mesin disc mill terhadap hasil penepungan porang. Penelitian ini dilakukan di PT. Daud Teknik Maju Pratama pada Januari – Mei 2024 dengan menggunakan bahan berupa 1 kilogram porang berukuran 1 cm untuk setiap perlakuan. Pengujian dilakukan dengan menggunakan tiga kecepatan putar pada mesin disc mill (2160 rpm, 2750 rpm, dan 3340 rpm). Pada setiap perlakuan dilakukan pengulangan sebanyak tiga kali. Pengujian dilakukan untuk memperoleh data kapasitas penepungan, rendemen, susut tercecer, daya mesin, dan kualitas penepungan. Hasil performansi menunjukkan kapasitas penepungan mesin disc mill berkisar antara 5,96 - 9,89 kg/jam. Nilai rendemen penepungan pada perlakuan kecepatan putar 3340 rpm mendapatkan hasil tertinggi (91,37%) dan susut tercecer terendah (8,63%). Hasil kualitas penepungan terbaik juga didapatkan pada perlakuan kecepatan putar 3340 rpm dengan nilai tertinggi partikel halus 28,54% lolos ayakan mesh 80 dan persentase penurunan kadar air tertinggi 4,17%. Daya motor listrik yang dibutuhkan untuk mesin disc mill dengan kecepatan putar 2160 rpm, 2750 rpm, dan 3340 rpm secara berturut sebesar 1,0961 kW, 1,3486 kW, dan 1,5456 kW., The porang plant is an abundant commodity that has a high chance of becoming an export commodity in the form of fresh tubers, dried chips, and flour. Flour from grinding porang tubers has a higher selling price than the price of fresh porang tubers. This creates an impetus for processing businesses so a porang tuber flouring machine with good flouring performance is needed. The disc mill type pressing machine is one of the pressing machines that can process porang up to 60-80 mesh size. This study aimed to analyze and test the performance of the disc mill machine on the results of milling porang. This research was conducted at PT. Daud Teknik Maju Pratama from January to May 2024 using 1 kilogram of porang measuring 1 cm for each treatment. Tests were carried out using three rotational speeds on the disc mill machine (2160 rpm, 2750 rpm, and 3340 rpm). Each treatment was repeated three times. Tests were conducted to obtain data on milling capacity, yield, shrinkage loss, engine power, and milling quality. The performance results showed that the milling capacity of the disc mill machine ranged from 5.96 - 9.89 kg/hour. The milling yield value in the 3340 rpm rotational speed treatment was obtained the highest result (91.37%) and the lowest shrinkage (8.63%). The best milling quality results were also obtained in the 3340 rpm rotary speed treatment with the highest value of fine particles 28.54% passing the 80 mesh sieve and the highest percentage reduction in water content of 4.17%. The electric motor power required for disc mill machines with rotating speeds of
Keyword: porang, disc mill, performance test, porang flour, flouring

Judul: Performance Test of Hammer Mill Machine for Hotong Flour (﻿Setaria italica ﻿L.).
Abstrak: Indonesia memiliki sumber keanekaragaman hayati yang tinggi tetapi pola konsumsi masih bergantung pada beras sebagai kebutuhan pangan pokok yang mengandung karbohidrat. Diversifikasi pangan perlu dilakukan untuk mencapai penganekaragaman pangan, khususnya tanaman yang dapat tumbuh di lahan kering seperti tanaman hotong. Hotong merupakan tanaman yang banyak tumbuh di Indonesia tetapi masih memiliki kendala pascapanen pada proses penepungan. Oleh karena itu, penelitian dilakukan untuk mengetahui kinerja mesin hammer mill dan membandingkan dengan disc mill. Penelitian dilakukan di PT. Daud Teknik Maju Pratama pada bulan Juli 2022 dengan bahan yang digunakan masing-masing 500 gram pada setiap pengujian. Kecepatan putar yang diuji pada mesin palu yaitu 2887 rpm, 3608 rpm, dan 4330 rpm, sedangkan mesin disc mill 4485 rpm. Pengujian dilakukan satu kali lintasan dengan tiga kali ulangan untuk setiap sampel dan kualitas penepungan diuji menggunakan ayakan mesh 80. Hasil uji performansi menunjukkan kapasitas tertinggi yaitu menggunakan mesin hammer mill 4330 rpm, sedangkan rendemen tertinggi dan susut tercecer terendah menggunakan disc mill. Selanjutnya, tepung hasil penggilingan menggunakan kedua mesin diayak menggunakan mesh 80 dan tepung yang lolos lebih banyak dihasilkan dari penggilingan mesin hammer mill 4330 rpm sebesar 45,111%. Daya yang dibutuhkan oleh mesin hammer mill untuk menggiling 500 gram hotong sebesar 5107,34 watt. Kata kunci: disc mill, hammer mill, hotong, penepungan, Performance Test of Hammer Mill Machine for Hotong Flour (Setaria italica L.). Supervised by AGUS SUTEJO. Indonesia has a high source of biodiversity but consumption patterns still depend on rice as a basic food needs containing carbohydrates. Food diversification needs to be done to achieve food diversification, especially plants that can grow on dry land such as hotong plants. Hotong is a plant that grows a lot in Indonesia but still has postharvest constraints on the flouring process. Therefore, the study was conducted to determine the performance of hammer mill machine and compare with disc mill. The research was conducted in PT. Daud Teknik Maju Pratama in July 2022 with materials used 500 grams each on each test. The rotational speed tested on the hammer machine is 2887 rpm, 3608 rpm, and 4330 rpm, while the disc mill machine is 4485 rpm. The test was carried out one pass with three repetitions for each sample and the quality of flouring was tested using an 80 mesh. Performance test results showed the highest capacity of using hammer mill machine 4330 rpm, while the highest yield and the lowest scattered shrinkage using disc mill. Furthermore, the flour milling using both machines sifted using mesh 80 and flour that passes more produced from milling hammer mill machine 4330 rpm of 45.111%. The power required by the hammer mill machine to milling 500 grams of hotong is 5107,34 watts. Keywords: disc mill, hammer mill, hotong, milling
Keyword: disc mill, hammer mill, hotong, penepungan

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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