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: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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