Judul: Karakterisasi Beberapa Varietas Jeruk Keprok Dataran Rendah
Abstrak: The research was conducted to characterize germplasms of Mandarins which have orange or orange-yellow epicarp color that is well-adapted in lowlands. Characterization was conducted on citrus in Padang Pangrapat and Rantau Panjang Village, Paser Regency, East Kalimantan, and Linggamanik Village, Cikelet District and Mekardaya Village, Bayongbong District, Garut in May-August 2012. The observations were referring to Descriptors for Citrus (International Plant Genetic Resources Institute, 1999). The character of observed citrus were compared with the similar variety that have been released by the Ministry of Agriculture; namely Keprok Borneo Prima (East Kalimantan), and Keprok Garut (Garut). The results showed that the citrus obtained in Padang Pangrapat and Rantau Panjang Village were not different each other, but different from Keprok Borneo Prima. The citrus obtained at Linggamanik Village was different from Keprok Garut. The citrus obtained at Mekardaya Village was similar to Keprok Garut.
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Judul: Analisis persepsi dan preferensi konsumen terhadap Jeruk Keprok Garut di Kabupaten Garut, Jawa Barat
Abstrak: In 1980 Jeruk Keprok Garut became the best local orange comodity and either had good quality and competitiveness with Jeruk Pontianak and Jeruk Medan. Jeruk Keprok Garut started to be less known by Indonesian after infected by Citrus Vein Phloem Degeneration (CVPD) and erupted of Gunung Galunggung in Tasikmalaya. And The Huge number of imported Orange in our market was supporting the reason why Jeruk Keprok Garut were being less known by local community (Indonesian).This study/research is intended to investigate the consumer characters, consumer perception and consumer preference toward Jeruk Keprok Garut. Based on the investigation, we obtained some conclusion that consumer characteristics were mostly women, especially who lived in the Districts around the City Center, who were have age around 25-35 years old, married and working with income of above Rp 2 000 000, Consumer was seeing that Jeruk Keprok Garut has a taste of fresh sweet with a little of acidity. It has high water content, clean yellow-green skin, fresh and strong aroma. The price was also relatively affordable and easily found in around Garut City Center (urban areas). Consumer preferences is measured by the Method of Conjoint, which shows that consumer are more inclined to chooseJeruk Keprok Garut with combinations of low price attributes that have range at the lowest price in the market of Rp 13 000- Rp 17 000 per kilogram, sweet taste, watery, and fresh aroma.
Keyword: Bogor Agricultural University (IPB), Conjoint., Jeruk Keprok Garut, Perception and Preference

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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