Judul: Produktivitas Serasah Dan Laju Dekomposisi Di Kebun  Campur Senjoyo Semarang Jawa Tengah Serta Uji  Laboratorium Anakan Mahoni (Swietenia macrophylla  King)  Pada Beragam Dosis Kompos Yang Dicampur EM4
Abstrak: Ketersediaan unsur hara penting bagi pertumbuhan vegetasi tanaman secara normal. Ketersediaan unsur hara yang cukup dan seimbang diindikasikan oleh perbedaan produksi serasah, dekomposisi serasah dan kehilangan air tanah melalui infiltrasi air ke dalam tanah. Pengembalian unsur hara oleh tanaman ke tanah pada dasarnya berhubungan dengan produktivitas serasah dan dekomposisi sehingga tercipta siklus unsur hara yang stabil. Penelitian ini bertujuan mengkaji produktivitas dan laju dekomposisi serasah kebun campur Senjoyo Semarang Jawa Tengah dan membuktikan pengaruh kompos serasah yang dicampur EM4 dari kebun campur Senjoyo Semarang Jawa Tengah sebagai media tanam terhadap pertumbuhan anakan Swietenia macrophylla King (mahoni) di rumah kaca.
Keyword: Semarang, Jawa Tengah, Anakan Mahoni, Swietenia macrophylla King, Laju Dekomposisi, Kompos dan EM4

Judul: Respons Pertumbuhan Mahoni terhadap Pemberian Arang Sekam, Kompos, dan NPK di Taman Hutan Kampus IPB
Abstrak: Lahan Kelompok Tani Hutan Kemang Sawargi yang terletak di Taman Hutan Kampus IPB memiliki kondisi tanah dengan kesuburan yang rendah. Kesuksesan penanaman dipengaruhi oleh kesuburan tanah yang baik serta pemilihan jenis yang tepat. Mahoni dipilih karena adaptif dan mampu hidup pada berbagai kondisi. Kemampuan pertumbuhan mahoni di lapangan dapat ditingkatkan dengan memberikan arang sekam, kompos, dan NPK. Penelitian ini bertujuan mengetahui respons pertumbuhan terhadap pemberian arang sekam, kompos, NPK, dan kombinasinya di lapangan. Interaksi perlakuan arang sekam, kompos, dan NPK memberikan pengaruh nyata terhadap pertambahan tinggi, jumlah akar, dan panjang akar mahoni. Faktor tunggal kompos memberikan pengaruh yang sangat nyata terhadap pertambahan tinggi, jumlah akar dan panjang akar mahoni. Pemberian kompos tanpa arang sekam dan NPK memberikan hasil terbaik bagi pertumbuhan parameter mahoni berupa tinggi, jumlah akar dan panjang akar., The land of Kelompok Tani Hutan Kemang Sawargi located in Taman Hutan Kampus IPB has soil conditions with low fertility. The success of planting is influenced by good soil fertility and the selection of the right type. Mahogany was chosen because it is adaptive and able to withstand various conditions. Mahogany growth ability in the field can be increased by providing husk charcoal, compost, and NPK. This study aims to determine the growth response to the provision of husk charcoal, compost, NPK, and their combination in the field. The interaction of husk charcoal, compost, and NPK treatments had a significant effect on the increase in height, number of roots, and root length of mahogany. The single factor of compost had a very significant effect on the increase in height, number of roots, and root length of mahogany. Provision of compost without husk charcoal and NPK gave the best results for the growth of mahogany parameters in the form of height, number of roots, and root length.
Keyword: compost, growth, husk charcoal, mahogany, NPK

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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