Judul: The Role of Mycorrhizal Arbuscular Fungi and Soil Ameliorants on Rhizosphere Bacteria of Sengon Laut in Post-Coal Mining Media
Abstrak: Gangguan seperti kegiatan pertambangan batu bara dapat mengurangi populasi mikroba di rhizosfer. Penelitian ini bertujuan menganalisis pengaruh pemberian berbagai dosis amelioran tanah serta Al dan Fe terhadap bakteri rhizosfer dan populasi Fungi Mikoriza Arbuskula (FMA) pada bibit sengon laut (Paraserianthes falcataria (L.) Nielsen) di media pascatambang batu bara. Rancangan percobaan yang digunakan adalah Rancangan Acak Lengkap dengan petak terbagi yang terdiri dari tiga perlakuan, yakni pemberian FMA, amelioran tanah (kompos, kapur, dan faba), serta dosis Al dan Fe. Hasil penelitian menunjukkan pengaruh tunggal pemberian FMA dan penambahan amelioran tanah dengan komposisi kapur 5% dan kompos 0,5% mendukung perkembangan bakteri pada rhizosfer bibit P. falcataria dengan rata-rata jumlah koloni sebesar 168 CFU/g sedangkan pemberian konsentrasi logam Al dan Fe dapat menekan perkembangan bakteri. Terdapat sembilan karakteristik morfologi koloni bakteri yang berbeda dilihat dari bentuk, tepi, elevasi, dan warna koloni. Koloni bakteri terbanyak ditemukan dengan karaktertistik round, entire, convex, dan berwarna putih., Disturbances such as coal mining activities will reduce the microbial population around the rhizosphere. This study aims to analyze the effects of various doses of soil ameliorant and metals (Al and Fe) to the rhizosphere bacteria and the population of Arbuscular Mycorrhizal Fungi (AMF) in Sengon Laut (Paraserianthes Falcataria (L.) Nielsen) seedlings using post-coal mining media. The experimental design used for this research was split plot design in a completely randomized design consist of three factors which are inoculation of AMF, soil ameliorant, and various doses of Al and Fe. The results showed single treatment of AMF inoculation and soil ameliorants with 0,5% lime and 5% compost support the growth of bacteria in the rhizosphere of P. falcataria seedlings with 168 CFU/g while the concentration of Al and Fe restrain the growth of bacteria. There were nine different morphological characteristics of bacterial colonies seen from the shape, margins, elevation, and colony color. The colony characteristic mostly found in this study is round, entire, convex, and white.
Keyword: Arbuscular mycorrhizae, bacteria, fly ash bottom ash, heavy metals, rhizosphere

Judul: Populasi Mikoriza Arbuskula dan Bakteri pada Rizosfer Bibit Trembesi (Samanea saman (Jacq.) Merrill) di Media Pascatambang Batubara
Abstrak: Kegiatan pertambangan dapat memberikan dampak negatif terhadap daerah rizosfer sehingga dapat memengaruhi tingkat kesuburan tanahnya. Salah satu teknik yang telah banyak dikembangkan dalam perbaikan dan peningkatan kualitas tanah adalah penggunaan bahan amelioran dan FMA. Penelitian ini bertujuan untuk: (1) menganalisis jumlah spora FMA dan bakteri pada rizosfer bibit S. saman; (2) menganalisis pemberian dosis Al dan Fe terhadap perkembangan spora FMA dan bakteri pada rizosfer bibit S. saman, dan (3) mengidentifikasi karakteristik morfologi bakteri. Rancangan percobaan adalah rancangan acak lengkap dengan petak terbagi. Perlakuan yang diberikan adalah FMA, bahan ameliorant tanah (kompos, kapur, dan faba) serta penambahan kadar Al dan Fe. Hasil penelitian menunjukkan bahwa FMA, amelioran faba 10% serta penambahan 2 mM Al dan 0,25 mM Fe mampu meningkatkan kepadatan spora FMA pada bibit S. saman. Pemberian amelioran berupa kompos 5% dan kapur 0,5% mampu meningkatkan jumlah bakteri pada bibit S. saman. Ditemukan 7 karakteristik morfologi bakteri yang berbeda.
Keyword: meliorant, bottom ash, correlation, fly ash, toxicit

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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