Judul: The Role of Arbuscular Mycorrhizae and Soil Ameliorants on Bacterial Populations in Sengon Merah’s Rhizosphere in Post-Coal Mining Media
Abstrak: Rhizosfer merupakan daerah di sekitar perakaran tanaman sebagai tempat aktivitas mikroorganisme tanah. Rhizosfer dapat rusak akibat dampak kegiatan penambangan. Rhizosfer dapat diperbaiki melalui kegiatan revegetasi dengan penggunaan Fungi Mikoriza Arbuskula (FMA) dan bahan amelioran untuk mendukung pertumbuhan dan perkembangan mikroorganisme tanah. Penelitian ini bertujuan untuk : 1) Menganalisis populasi bakteri dan spora FMA pada rhizosfer sengon merah yang tumbuh pada media tanah pascatambang batu bara yang diberi berbagai perlakuan bahan amelioran tanah; (2) Menganalisis dosis Al dan Fe yang dapat mempengaruhi perkembangan bakteri dan spora FMA di rhizosfer sengon merah. Rancangan percobaan yang digunakan dalam penelitian ini adalah rancangan acak lengkap (RAL). Hasil penelitian menunjukkan bahwa amelioran tanah berupa kompos 5 %, kapur 0,5 %, dan FABA 10% merupakan komposisi terbaik dalam meningkatkan populasi spora FMA pada rhizosfer tanaman A. chinensis. Kombinasi FMA dengan FABA 10 % memberikan pengaruh positif terhadap perkembangan bakteri di rhizosfer A. chinensis. Pemberian dosis Al dan Fe sampai dengan dosis 6 mM Al + 1,25 mM Fe belum berpengaruh negatif terhadap populasi bakteri dan FMA.
Keyword: A. chinensis, ameliorant, bacteria, AMF, rhizosphere

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: 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: