Judul: Growth of Arbuscular Mycorrhizal Fungi and Bacterial Populations in the Trembesi’s Mycorrhizosphere (Samanea saman (Jacq.) Merrill)
Abstrak: Mikorhizosfer merupakan wilayah di sekitar perakaran tumbuhan yang bermikoriza dan umumnya terdapat banyak mikroorganisme. Tujuan dari penelitian ini adalah untuk menganalisis jumlah spora Fungi Mikoriza Arbuskula (FMA), populasi dan karakter morfologi bakteri pada mikorhizosfer semai trembesi yang tumbuh di media pascatambang dengan wadah pot organik. Bahan yang digunakan adalah benih trembesi, koran, tanah pascatambang, kompos (bokashi), cocopeat, dan rock phosphate. Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap (RAL) yang terdiri atas 3 faktor, yaitu FMA, komposisi pot organik, dan ukuran bahan pot. Hasil penelitian menunjukkan interaksi faktor inokulasi FMA dan komposisi pot berpengaruh nyata dengan selang kepercayaan 95% pada jumlah spora FMA, kolonisasi akar, dan populasi bakteri. Karakter koloni bakteri yang mendominasi ialah berwarna putih susu, berbentuk bulat, tepian licin/rata, dan elevasi cembung.
Keyword: colonization, correlation, morphology, organic pot

Judul: Populasi Fungi Mikoriza Arbuskula dan Bakteri pada Mikorhizosfer Semai Trembesi (Samanea saman (Jacq.) Merrill) dalam Pot Organik
Abstrak: Mikorhizosfer merupakan modifikasi khusus di lingkungan sekitar miselium fungi mikoriza arbuskula (FMA). Penelitian ini bertujuan untuk : (1) menghitung jumlah spora FMA dan populasi bakteri, serta karakter morfologi bakteri yang terdapat pada mikorhizosfer semai trembesi; (2) menghitung kolonisasi akar pada semai trembesi. Bahan yang digunakan adalah benih trembesi, kertas koran, tanah pascatambang, kompos, cocopeat. Metode yang digunakan adalah penghitungan jumlah spora FMA, kolonisasi FMA, koloni bakteri, serta karakteristik morfologi bakteri. Rancangan percobaan yang digunakan adalah rancangan acak lengkap (RAL) dua faktor yaitu ukuran bahan dan komposisi bahan. Komposisi pot organik B menunjukkan hasil terbaik pada jumlah spora FMA serta populasi koloni bakteri media tanam. Komposisi pot organik C menunjukkan hasil terbaik pada jumlah spora FMA serta populasi koloni bakteri pot. Persentase kolonisasi akar terbaik ditunjukkan pada komposisi pot organik A. Terdapat delapan karakter morfologi bakteri yang ditemukan., The mycorrhizosphere is a specific modification in the environment surrounding the mycelium of arbuscular mycorrhizal fungi (AMF). This study aims to : (1) count the number of spores and populations of AMF bacteria, and morphological characteristics of bacteria found in the mycorrhizosphere of trembesi; (2) count root colonization in trembesi seedlings. The materials used are trembesi seeds, used newspapers, post-mining soil, compost, cocopeat. The method used is counting the number of AMF spores, AMF colonization, bacterial colonies, and the morphological characteristics of the bacteria. The experimental design used was a completely randomized design (CRD) of two factorial patterns, namely the sizes of the material and the composition of the materials. The organic potting composition B showed the best results on the number of AMF spores and the population of bacterial colonies in the media. The organic pot composition C showed the best results on the number of AMF spores and the population of pot bacterial colonies. The best percentage of root colonization was shown in the organik pot composition A. There are eight bacterial morphological characters found.
Keyword: bakteri, fungi mikoriza arbuskula (FMA), komposisi, korelasi, rhizosfer, AMF, bacteria, composition, correlation, rhizosphere

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: