Judul: Kajian Proses Pembuatan dan Penyimpanan  Kering (Dehydrated Green Pepper ) Disertai Nilai Karakteristik Mutunya
Abstrak: Dalam rangka untuk meningkatkan nilai tambah komoditas lada maka perlu dilakukan diversifikasi produk lada. Lada hijau kering (dehydrate green pepper) merupakan salah satu bentuk diversifikasi produk lada tersebut.
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Judul: Aplikasi Metode Arrhenius dalam Pendugaan Umur Simpan Lada Hijau Kering (Dehydrated Green Pepper)
Abstrak: Pepper (Piper ningrum L.) is a kind of spices from family Piperaceae. Dehydrated green pepper has spesific flavor and natural green appearance. This kind of pepper also has higher sell value than black pepper and white pepper in international market. Prediction of shelf life aims to know shelf life of dehydrated green pepper in certain condition. Determination shelf life product with ASS (Accelerated Storage Studies) method using environmental condition parameter enables to accelerate degradation process of quality of food product. The right packaging and storage is expected to detain deterioration rate of dehydrated green pepper and increase shelf life. The objectives of the research is to know quality changing, to determine shelf life, and to obtain better packaging to defend quality of dehydrated green pepper. The packaging materials used in this research were plastic LDPE, PP, and aluminium foil. The storage has been done in temperatures 20°C, 30°C, and 40°C during 4 months. The analysis of dehydrated green pepper were colour, water content, volatile oil content, and sensory evaluation analysis. Based on this research, it is showed that dehydrated green pepper quality changed during 4 months of storage. The green colour of dehydrated green pepper decreased with a* value at storage temperature of 20°C, 300C, 400C increased by 0.0039%, 0.0068%, and 0.0169% per day for LDPE; 0.0017%, 0.0026%, 0.0162% per day for PP; and 0.001%, 0.002%, dan 0.0196% per day for aluminium foil. Water content at storage 200C dan 300C increased by 0.0127% dan 0.0249% per day for LDPE; 0.0115% and 0.0224% per day for PP; 0.0119%, 0.0126%, and at storage 400C increased by 0.0071% per day for aluminium foil. Water content at storage 400C decreased by 0.037% per day for LDPE dan PP. Volatil oil content of dehydrated green pepper at storage temperature of 20°C, 300C, 400C decreased by 0.0013%, 0.0014%, 0.0019% per day for LDPE; 0.0010%, 0.0012%, 0.0017% per day for PP; and 0.0004%, 0.0008%, 0.0009% per day respectively for aluminium foil. pH of dehydrated green pepper at storage temperature of 20°C, 300C, 400C decreased by 0.0001%, 0.0005%, 0.0002% per day for LDPE; 0.0002%, 0.0002%, 0.0001% per day for PP; and 0.00001%, 0.0001%, 0.0004% per day for aluminium foil. Based on a* value parameter with its critical point of +2.79, shelf life of dehydrated green pepper is 36 months 8 days (200C), 17 months 3 days (300C), 8 months 15 days (400C) for LDPE; 104 months 24 days (200C), 32 months 23 days (300C), 11 months 3 days (400C) for PP; 182 months 18 days (200C), 38 months 24 days (300C), 9 months 3 days (400C) for aluminium foil Thereby, the best packaging to maintain the quality of dehydrated green pepper is aluminium foil.
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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