Judul: Pengaruh penggunaan dedak padi yang di fermentasi dengan Aspergillus niger dalam ransum dengan serat kasar tinggi terhadap penampilan produksi dan ketersediaan mineral P, Ca dan Mg ayam pedaging
Abstrak: Penelitian ini dilaksanakan di dua lokasi yaitu di bagian Mikrobiologi LBN LIPI Bogor dan di bagian Jurusan Ilmu Nutrisi dan Makanan Ternak Fakultas Peternakan Institut Pertanian Bogor, sejak bulan Mei sampai dengan bulan Oktober 1989.
Keyword: Rice bran, Aspergillus niger, Mineral

Judul: Biokonversi dedak padi oleh kapang aspergillus ficuum sebagai upaya menurunkan kadar fitat dan pengaruhnya terhadap kinerja ayam petelur
Abstrak: Three experiments were conducted to evaluate the performance of laying hens fed on fermented rice bran (FRB) utilizing A. ficuum. First, the phytase-producing ability of A. ficuum was tested. The mold produce 2.561 AU of phytase was grown for 88 hours on rice bran medium. Second, in vitro and in vivo studies were carried out on rice bran before and after fermented utilizing A. ficuum. Fermentation of rice brand reduced phytic acid by about 83.25 persen, but had no effect on protein digestibility. Protein content, Ca and P retention, and P availability in FRB were higher (P<0.05) than in unfermented rice bran (URB). There were no differences in metabolizable energy content and N retention. Third, five treatment-diets and a control diet were each fed to five groups of four hens in individual battery cages. The treatment diets contained 10 to 50 persen FRB, the control diet contained 30 persen URB. All diets contained 15 persen protein with 2650 kcal/kg ME and had similar Ca, Pav, lysine methionine and TSAA contents. Egg production, egg weight, feed conversion, Haugh unit, shell thickness, yolk index, Ca retention and Mg content of shell were not affected by fermentation. Feed consumption and P retention in shell of hens fed FRB diets were higher (P<0.05) than those fed the control diet. The higher FRB content of diet increased (P<0.05) feed conversion, P retention and Mg content of shell; reduced (P<0.05) feed consumption, egg production and yolk in-index. Egg weight, Haugh unit, shell thichness and Ca retention in shell were not affected.
Keyword: Biokonversi; Aspergillus ficuum; feed conversion.

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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