Judul: Development of Potato Flour Business Unit in  Modoinding District, South Minahasa
Abstrak: Produksi kentang di Kecamatan Modoinding, Kabupaten Minahasa Selatan cukup tinggi saat panen raya, tetapi hasil panen melebihi permintaan pasar. Selain enyakit fusarium pada kentang memaksa panen dilakukan sebelum 90 hari. Kentang yang kaya karbohidrat dapat diolah menjadi tepung kentang, sehingga dibutuhkan unit pengolahan tepung. Proyek ini bertujuan merancang proses pembuatan tepung kentang secara rinci, menguji kinerja tepung dalam meningkatkan mutu produk pangan, mengevaluasi karakteristik tepung pada produk turunan, dan merancang alat pengeringan energi yang efisien. Metode yang digunakan mencakup desain proses pembuatan tepung, uji kinerja tepung pada produk mie komposit pati sagu dan tepung kentang, serta desain alat drum dryer untuk pengeringan dengan penggunaan energi yang lebih. Hasil uji menunjukkan bahwa mie komposit dengan konsentrasi 60% tepung kentang dan 40% sagu menghasilkan mie yang berwarna kuning dengan tekstur kenyal, elastis, dan waktu pemasakan cepat. Kadar proksimat tepung kentang adalah air 7,4%, protein 10,4%, lemak 0,4%, abu 0,8%, dan karbohidrat 80,4%. Drum dryer dipilih karena efisiensi penggunaan energinya lebih tinggi, dengan kapasitas 31 kg/jam untuk mengeringkan 600 kg bahan dengan diameter 3,6 meter dan tinggi 1,8 meter. Perubahan viskositas gliserol sebagai pemanas pada fluida yang drastis dengan perubahan suhu memiliki dampak yang signifikan pada perpindahan panas., The potato production in Modoinding District, South Minahasa, was quite high during the harvest season, but it exceeded the market demand. Fusarium disease also required early harvest within 90 days. The carbohydrate-rich potatoes could be processed into potato flour, necessitating a flour processing unit. The project aimed to design a detailed process for making potato flour, tested its performance in improving food product quality, evaluated flour characteristics in derived products, and designed an energy-efficient drying equipment. The methods included flour production process design, performance testing on composite noodle products made from sago starch and potato flour, and designing a drum dryer for efficient drying with less energy usage. Test results showed that composite noodles with 60% potato flour and 40% sago starch had yellow color, chewy and elastic texture, and quick cooking time. The proximate composition of potato flour included 7.4% water, 10.4% protein, 0.4% fat, 0.8% ash, and 80.4% carbohydrates. The drum dryer was chosen for its higher energy efficiency, with a capacity of 31 kg/hour to dry 600 kg of material, with a diameter of 3.6 meters and height of 1.8 meters. The significant impact of glycerol's viscosity changes as a heating fluid with temperature variation was observed on heat transfer.
Keyword: Drum dryer, Potato, Potato flour

Judul: Financial Analysis of  Mashed Potato and Potato Flour Production Unit Development in Modoinding  Desctrict South Minahasa Regency
Abstrak: Produk mashed potato dan tepung kentang potensial untuk dikembangkan sebagai alternatif solusi dari permasalahan jumlah produksi dan rendahnya penyerapan pasar kentang di Minahasa Selatan berdasarkan aspek keberlanjutan usaha. Tujuan penelitian ini adalah menganalisis kelayakn finansial dan sensitivitas pengambangan unit produksi mashed potato dan tepung kentang. Metode yang digunakan pada penelitian ini adalah metode kuantitatif yang dimulai dari perhitungan Harga Pokok Produksi (HPP), penentuan harga jual, Net Present Value (NPV), Internal Rate of Return (IRR), Net Benefit Cost Ratio (Net B/C), payback period, dan analisis sensitivitas. Hasil perhitungan menghasilkan HPP sebesar Rp 47,182 untuk produk mashed potato dan Rp 59,739 untuk produk tepung kentang. Hasil perhitungan analisis kelayakan menghasilkan nilai NPV sebesar Rp1,346,988,430 nilai IRR sebesar 46%, Net B/C sebesar 1,24 dan Payback Period selama 0,75 tahun. Analisis sensitivitas yang dilakukan untuk pengembangan unit produksi ini menunjukkan bahwa peningkatan harga bahan baku sebesar 25% dan 50% serta penurunan harga jual sebesar 10% dan 20% tidak terlalu sensitif sehingga pengembangan unit produksi ini masih tetap layak untuk dijalankan., Mashed potato and potato flour products have the potential to be developed as an alternative solution to the problem of low production and low market absorption of potatoes in South Minahasa based on business sustainability aspects. The purpose of this study was to analyze the financial feasibility dand sensitivity of mashed potato and potato flour production unit development. The method used is a quantitative method which consists of calculating the Cost of Production (HPP), product selling prices, Net Present Value (NPV), Internal Rate of Return (IRR), Net Benefit Cost Ratio (Net B/C), payback period, and sensitivity analysis. The calculation results cost of production of IDR 47,182 for mashed potato product and IDR 59,739. The calculation financial feasibility results NPV value of IDR Rp1,346,988,430, IRR of 46 %, Net B/C of 1.24, and payback period of 0.75 years. The sensitivity analysis carried out for the development of this production unit shows that an increase in raw material prices by 25% and 50% and a decrease in selling price by 10% and 20% are not too sensitive so that the development of this production unit is still feasible.
Keyword: production unit, potato flour, mashed potato, financial feasibility

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