Judul: Design and Performance Test of Hammer Mill Crusher Machine for Coconut Shell Charcoal
Abstrak: Proses reduksi ukuran arang merupakan langkah pertama untuk memudahkan portabilitas dan pemanfaatan/pengolahan lanjut arang. Selain membutuhkan waktu yang lama, proses crushing arang tempurung kelapa secara manual menghasilkan butiran arang yang bervariasi ukuran dan bentuk partikelnya. Ketidakseragaman tersebut akan berdampak pada proses pengolahan lanjutan ataupun kualitas produk yang dihasilkan. Tujuan dari penelitian ini adalah merancang mesin crusher arang tempurung kelapa untuk industri skala kecil dan mikro, serta melakukan uji kinerja mesin tersebut. Mesin yang dirancang memiliki 15 swinging hammer yang terbuat dari bahan mild steel dengan tebal 3 mm pada poros berdiameter 30 mm. Di bagian bawah mesin dipasang saringan berukuran 2 mm (10 mesh) agar produk yang keluar relatif seragam yaitu 10 mesh. Tenaga penggerak yang digunakan adalah motor listrik dengan daya 2 HP dan putaran 1435 rpm. Hasil uji kinerja mesin dilakukan pada kecepatan putar 599 rpm, 1099,7 rpm, dan 1447 rpm menunjukkan bahwa kinerja terbaik diperoleh pada kecepatan putaran 1443,3 rpm. Kapasitas mesin yang diperoleh pada kecepatan putaran 1443,3 rpm adalah 21,29 kg bahan/jam, dengan tingkat efisiensi kemampuan penghancuran (crushing) 96,3%, susut produk tercecer 3,6% dan kebutuhan energi spesifik bahan yang diproses 0,052 kWh/kg bahan., Size reduction process of the charcoal is the first step to elevate portability and further utilization in charcoal processing. Crushing coconut shell charcoal manually produces charcoal grains that have various sizes and shapes. Various size and shapes will be influencing further process and quality of the product. The purpose of this research is to design hammer mill crusher machine for coconut shell charcoal for micro and small scale industries, and to conduct performance test of machine. The machine designed has 15 swinging hammers made of mild steel on its shaft with 30 mm diameter. The 2 mm sieve screen was placed at the bottom of the hammers The machine powered by 2 HP electric motor with maximum rotational speed of 1435 rpm. The performance test conducted with rotational speed of 599 rpm, 1099.7 rpm, and 1447 rpm, showing that optimum performance is at 1433.3 rpm. Performance test on 1443.3 rpm has an average machine capacity of 21.29 kg/hour, with crushing efficiency 96.3%, product losses 3.6%, and energy specific 0.052 kWh/kg raw material.
Keyword: coconut shell charcoal, crusher machine, hammer mill

Judul: Pre-Design Study of Coconut Shell-Based Product Processing Industy into Charcoal, Briquettes Charcoal and Activated Charcoal
Abstrak: Pemanfaatan tempurung kelapa menjadi produk arang, briket arang, dan arang aktif merupakan usaha prospektif dalam upaya memberikan nilai tambah terhadap komoditas kelapa Indonesia. Tujuan dari penelitian ini adalah mengkaji potensi tempurung kelapa, mengetahui potensi pasar impor dan ekspor, mengkaji kelayakan perancangan usaha berbasis tempurung kelapa berdasarkan aspek finansial, serta merancang usaha berbasis tempurung kelapa. Ruang lingkup penelitian meliputi analisis pasar dan pemasaran, teknis dan teknologi, manajemen dan organisasi, serta analisis finansial. Perancangan industri ditempatkan di provinsi Riau dengan total ketersediaan tempurung kelapa sebesar 0,04 juta ton/tahun dan membutuhkan 3% tempurung kelapa untuk di produksi menjadi arang, briket arang, dan arang aktif. Kapasitas produksi yang dirancang sebesar 1441,93 kg/hari arang; 320,62 kg/hari briket arang; dan 282,11 kg/hari arang aktif. Proses produksi arang akan menghasilkan limbah padat dan gas yang dapat dimanfaatkan menjadi produk turunan dari proses produksi arang. Berdasarkan analisis aspek finansial produk arang, briket arang, dan arang aktif menunjukkan nilai kelayakan secara finansial dengan nilai NPV, IRR, Net B/C, dan PBP yang memenuhi kriteria., Charcoal, briquette, and activated charcoal is a prospective product to provide added value to Indonesian coconut commodities. The purpose of this research is to study the potential of coconut shells, to find the potential import and export markets, to study the feasibility of designing a coconut shell based on financial aspect, to design a coconut shell business. The research scope includes market and marketing analysis, technical and technology, management and organization, and financial. The design is placed in Riau province with 0.04 million tons / year and requires 3% coconut shell to be produced . The designed production capacity is 1441.93 kg / day of charcoal; 320.62 kg / day charcoal briquettes; and 282.11 kg / day of activated charcoal. The charcoal production process will produce solid waste and gas which can be used as a byproduct of the charcoal production process. Based on the analysis of the financial aspects of the products of charcoal, charcoal briquettes, and activated charcoal, it shows the value of financial feasibility with NPV, IRR, Net B / C, and PBP values that meet the criteria.
Keyword: activated charcoal, briquettes, coconut charcoal, design, financial analysis

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model