Judul: Penentuan Titik Kritis Pascapanen Pepaya Carica papaya L. (Studi Kasus di Sentra Produksi Pepaya di Kabupaten Sukabumi, Banyumas, Kebumen, dan Boyolali)
Abstrak: Papaya (Carica papaya L.) is one a tropical fruit which is popular in Indonesia. Papaya is perishable fruits and has short postharvest life. Due to lack postharvest handling and its facility, losses in postharvest handling of papaya is still high. The range of total losses in postharvest handling for papaya is 25-40 percent. This total losess is identified from harvesting activity to the market. There are some actors in postharvest handling contribute in total losess. The objective of this study was to identify supply chain of papaya, to assess losess of papaya in supply chain, and to determine the critical point of postharvest losses of papaya. This study was carried out in the production center of papaya in Sukabumi (West Java), Banyumas, Kebumen and Boyolali (Central Java). The study was conducted by in dept-interview to all actors in supply chain of papaya, field observation to identify the supply chain and post-harvest losses and measurement of losess at each actors activities. The results showed that supply chain of papaya consists of farmers, collectors, suppliers, wholesalers, and retailers. The critical points of losess in postharvest handling of papaya in Kebumen and Boyolali was observed at the level of retailer. The different result was obtained in Sukabumi and Banyumas. In Sukabumi, the critical point in postharvest losess was found at suppliers level, in Banyumas was observed at wholesaler level.
Keyword: 

Judul: Penentuan Titik Kritis Susut Pascapanen Pisang (Studi Kasus Sentra produksi Pisang Kabupaten Cianjur)
Abstrak: Postharvest handling of tropical fruits is still the major problem in Indonesia due to lack of facility and knowledge of the farmer. This condition has caused the losses both in quatity and quality of fruits during distribution from the production centre to the market. Some researchers reported that total postharvest losses of tropical fruits in developing countries is 20-50%. However, no available data shows in which postharvest handling point and who is the actor take responsibility. The objectives of this study were to investigate the losess in postharvest handling of banana in supply chain, to measure the value of losess of postharvest handling in each actors, to identify the cause of postharvest handling losses and to analyze the efficiency of marketing in supply chain of banana. This study was conducted in banana central production in Cianjur. The results show that there were three marketing channel in supply chain of banana in central production Cianjur. First channel was Farmers – collector - Retailer - Consumer). Second channel was Farmers - Collectors – wholesaler - Retailer - Consumer). Third channel was Farmers – village collector – Big collector – Supermarket - Consumer. Quantitatively, the critical point of banana postharvest handling in the first channel was occured in collector i.e. 10.90% with total losses was 15.25%. For second channel, totall losses was 16.77% with the highest losses occured at village collector level i.e. 8.44%. For third channel, total losses was 39.30% with the highest losses occured at supermarket i.e. 32.13%. Qualitatively, for the first channel, losses postharvest handling of banana was 23% where all losses occured in the level of trader. The second channel, total losses was 57.73% with the highest losses occured in village collector level i.e. 48.96%. For third channel, total loss was 49.96% and the highest losses occured in the big collector level i.e. 29.36%. Among the channels in the supply chain of banana in central production of banana in Cianjur, the first channel was identified as the most efficient channel due to lower margin in trading which providing the biggest farmer's share. The cost benefit ratio in first channel was also higher than those second and third channel.
Keyword: 

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.
Keyword: