Judul: Penanganan Pascapanen Kale (Brassica oleracea var. acephala) di Rumah Sayur Cisarua
Abstrak: Kale (Brassica oleracea var. acephala) merupakan komoditas hortikultura dengan nilai ekonomi yang tinggi karena mengandung nutrisi yang penting bagi kesehatan tubuh. Sumber nutrisi yang terkandung pada setiap 100 g kale yaitu karbohidrat, lemak, protein kasar, air, serat kasar, abu, dan energi. Kale juga mengandung vitamin, mineral, dan kaya akan senyawa antioksidan. Banyaknya peminat kale dari berbagai daerah dan negara, maka perlu dilakukan pascapanen yang memadai agar mutu dan kesegaran kale dapat terjaga selama pengiriman ke konsumen. Namun, pada Rumah Sayur Cisarua yang berlokasi di Kabupaten Bandung Barat belum dilakukan penanganan pascapanen yang memadai sehingga kale mengalami penurunan mutu hanya dalam waktu 6 – 8 jam. Penelitian ini bertujuan merancang penanganan pascapanen untuk kale guna mempertahankan mutu dan kesegarannya. Penanganan pascapanen hortikultura dapat dilakukan dengan heat shock dan hydrocooling. Penelitian pendahuluan dilakukan untuk mengetahui efek yang lebih baik dari kedua perlakuan tersebut. Hydrocooling dipilih oleh mitra karena penampakan kale lebih segar dan tidak mengalami susut bobot. Selanjutnya, hydrocooling dilakukan variasi waktu perendaman 5, 8, dan 11 menit serta disimpan dengan dua skema penyimpanan: a) suhu ruang (20 – 25oC); b) suhu ruang (20 – 25oC) selama 5 jam dan dilanjutkan dalam showcase (5 – 8oC). Kale dengan skema penyimpanan pertama mengalami perubahan warna daun pada hari pertama. Kale dengan skema penyimpanan kedua mengalami perubahan warna daun pada hari keempat. Waktu perendaman yang dipilih oleh mitra adalah 11 menit dengan skema penyimpanan kedua, karena penampakan kale yang segar dan mengalami susut bobot yang lebih kecil dibandingkan waktu perendaman lainnya.
Keyword: heat shock, hydrocooling, kale, penanganan pascapanen

Judul: Kombinasi Suhu Air dan Lama Perendaman pada Hydrocooling untuk Mempertahankan Kesegaran Sawi Hijau (Brassica juncea)
Abstrak: Green cabbage is a vegetable which is susceptible to heat and easy to wilt. Hydrocooling treatment is an effort to preserve the freshness of green cabbage. The objective of hydrocooling treatment is to reduce field heat of material after harvesting. Based on that fact, this research was conducted to determine the combination of water temperature and immersion time in hydrocooling treatment which gives the best influence to preserving the quality of green cabbage. The method was to determine the optimal temperature of material based on the respiration rate and quality changes of green cabbage during storage. Then, the determination of the combination between water temperature and immersion time for hydrocooling conducted based on the optimal temperature and observes the hydrocooling effect in changes quality of green cabbage. The optimal temperature for green cabbage is 13oC. The result of water temperature and immersion time combination for reach the temperature of 13oC is: the hydrocooling on 5oC during 3.1 seconds and hydrocooling on 10°C during 3.9 seconds. Hydrocooling have a good influence on all quality parameters of green cabbage.
Keyword: storage, quality, hydrocooling, Green cabbage

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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