Judul: Physical and Organoleptical Properties of Goat Milk Probiotic Yogurt with Addition of Red Fruit (Pandanus conoideus)
Abstrak: Yogurt susu kambing merupakan jenis minuman yang berasal dari susu kambing etawah yang memiliki ciri rasa asam, dan segar dari proses fermentasi. Buah merah merupakan tumbuhan endemik Papua. Buah merah membantu penyembuhan penyakit, termasuk kanker dan HIV/AIDS. Penelitian ini bertujuan menganalisis sifat fisik dan organoleptik yogurt susu kambing dengan penambahan ekstrak buah merah. Taraf pemberian ekstrak buah merah tersebut adalah 0% (P0), 2,5% (P1) dan 5% (P3). Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan tiga kali pengulangan. Pengujian sifat fisik adalah nilai pH, nilai aw, viskositas dan total asam tertitrasi (TAT). Pengujian sifat organoleptik yang dianalisis adalah flavour, warna, aroma, dan tekstur. Data sifat fisik dianalisis dengan ANOVA satu faktor dan diuji lanjut dengan uji Duncan, hasil menunjukkan bahwa perbedaan penambahan ekstrak buah merah pada yogurt berpengaruh nyata (P<0,05) pada pH. Data sifat organoleptik dianalisis dengan uji non parametrik Kriskal-wallis dan diuji lanjut dengan Mann Whitney hasil hedonik menunjukkan berpengaruh nyata (P<0,05) pada parameter warna, sedangkan pada mutu hedonik berpengaruh sangat nyata (P<0,01) pada warna, aroma, flavor, dan kekentalan., Goat milk yogurt is a type of drink derived from goat's milk etawah which has a sour taste, and fresh from the fermentation process. Red fruit is a plant endemic Papua. Red fruit helps cure diseases, including cancer and HIV / AIDS. The research was aimed to analyze the physical and organoleptical properties of goat's milk yogurt with the addition of red fruit extract. Those levels consisted the control 0% (P0), 2,5%(P1), and 5%(P2) of red fruit extract. The research used completely randomized design (CRD) with three replications. The observed variables of physical properties were pH, aw, viscosity and total acid titrated (TAT). The observed organoleptic properties were flavor, color, aroma, and texture. Physical data were analyzed by one-factor ANOVA and further tested by Duncan test, the results showed that the difference in the addition of red fruit extract to yogurt had a significant effect (P <0,05) on pH. Organoleptic properties data were analyzed by non-parametric Kruskal-wallis test and further tested with Mann Whitney, the hedonic results showed a significant effect (P<0,05) on color parameters, while the hedonic quality had a very significant effect (P<0,01) on color, aroma, flavor and viscosity.
Keyword: buah merah, fisik, organoleptik, yogurt susu kambing

Judul: Physical and Organoleptic Properties of Probiotic Yogurt With The Addition of Red Fruit (Pandanus conoideous L.).
Abstrak: Yogurt can be made from homogenized milk, low-fat milk or skimmed milk with the addition of powdered milk. Starter culture commonly used in yogurt is Lactobacillus bulgaricus and Streptococcus thermophillus can not survive in environments with high acidity, so probiotics needed. One of the fruits that can be used in the process of making yogurt is red fruit (Pandanus Conoideus L). The observed physical characteristics consist of pH, viscosity, total acid concentration and water activity (aw) and organoleptic arachnids observed consisting of color, flavour, aroma and consistency. This research using a complete randomized design (RAL. The results showed that the addition of red fruit has a real effect (P<0.05) on pH, viscosity and total acid titrated and organoleptic test shows the addition of red fruit has a noticeable effect on color, flavour, aroma and viscosity in hedonic quality tests, then in hedonic tests affect aroma and flavour. Based on the results of yogurt testing with the addition of 2.5% this is the closest to control and acceptable to indonesian national standards (SNI)., Yogurt dapat dibuat dari susu yang telah dihomogenisasi, susu berkadar lemak rendah atau susu skim dengan penambahan susu bubuk. Kultur starter yang biasa digunakan dalam yogurt yaitu Lactobacillus bulgaricus dan Streptococcus thermophillus tidak dapat bertahan pada lingkungan dengan keasaman yang tinggi, sehingga diperlukan probiotik. Salah satu buah yang dapat ditambahkan adalah buah merah (Pandanus Conoideus L). Karakteristik fisik yang diamati terdiri atas pH, viskositas, total asam tertitrasi dan aktivitas air (aw) serta karakteristik organoleptik yang diamati terdiri atas warna, flavour, aroma dan kekentalan. Penelitian dilakukan dengan menggunakan rancangan acak lengkap (RAL). Hasil penelitian menunjukan bahwa penambahan buah merah berpengaruh nyata (P<0,05) terhadap pH, viskositas dan total asam tertitrasi. Uji organoleptik memperlihatkan penambahan buah merah berpengaruh nyata terhadap warna, flavour, aroma dan kekentalan pada uji mutu hedonik, lalu pada uji hedonik berpengaruh pada aroma dan flavour. Berdasarkan hasil pengujian yogurt dengan penambahan 2,5% ini yang paling mendekati dengan kontrol dan memenuhi standar nasional Indonesia (SNI).
Keyword: yogurt, red fruit, probiotic, characteristic physic, characteristic organoleptic

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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