Judul: Model Pendugaan Produksi Benih Indigofera zollingeriana Miq.
Abstrak: Model pendugaan produksi benih sangat penting dalam membantu proses perencanaan produksi lebih akurat. Penelitian ini bertujuan membangun model penduga produksi benih Indigofera di UP3J-IPB, Bogor, Jawa Barat. Metode yang digunakan yaitu purposive sampling pada 9 pohon. Variabel yang digunakan yaitu jumlah cabang, ranting, tandan, polong, biji, dan bobot 1000 biji. Pembangunan model pendugaan menggunakan analisis deskriptif, analisis korelasi, dan analisis regresi linier berganda. Pengategorian produksi benih menggunakan uji lanjut Tukey. Uji daya kecambah benih menggunakan ANOVA dan uji lanjut LSD. Hasil penelitian diperoleh tiga model penduga produksi benih Indigofera yaitu Yb1 (g) = 101,290 + 11,817X1 (jumlah cabang) + 0,088X4 (jumlah polong)  0,004X5 (jumlah biji) (r=97,1%), Yb2 (g) = 97,609 + 0,050X4 (jumlah polong) (r=97,3%), dan Yb3 (g) = 122,460 + 483,266X1 (jumlah cabang) (r=38,9%). Kategori produksi benih terdiri dari, produksi rendah (<6000 polong), produksi sedang (600015000 polong), produksi tinggi (>15000 polong). Kategori produksi rendah dan produksi tinggi memiliki daya kecambah lebih tinggi (95%) daripada produksi sedang (81%)., The seed production estimation model is important to support the planning of production process accurately. This research aims was to develop a model of Indigofera seed production at UP3J-IPB, Bogor, West Java. The method was purposive sampling on 9 trees. The variables used are the number of branches, twigs, bunches, pods, seeds, and the weight of 1000 seeds. The development of the estimation model useds descriptive analysis, correlation analysis, and multiple linier regression analysis. The seed production categories was determine by Tukey’s advanced test. The seed sprout power test uses ANOVA and continues LSD testing. The results of the study obtained three estimating models of Indigofera seed production, namely Yb1 (g) = 101,290 + 11,817X1 (number of branches) + 0,088X4 (number of pods)  0,004X5 (number of seeds) (r=97,1%), Yb2 (g) = 97,609 + 0,050X4 (number of pods) (r=97,3%), dan Yb3 (g) = 122,460 + 483,266X1 (number of branches) (r=38,9%). The seed production category, namely low production (<6000 pods), medium production (600015000 pods), high production (>15000 pods). The low production and high production categories have higher sprout power (95%) than medium production (81%).
Keyword: Indigofera, model, regression, seed

Judul: Indigofera sp. Seed Growth Test with Different Storage Duration
Abstrak: Indigofera sp. merupakan leguminosa yang tumbuh di tropis yang dapat dipergunakan menjadi hijauan pakan ternak dan suplemen kualitas tinggi untuk ternak karena kandungan nutrisinya yang tinggi. Penting untuk mengidentifikasi durasi penyimpanan benih yang tepat, yang memungkinkan tingkat perkecambahan benih yang tinggi. Penelitian ini bertujuan untuk mengetahui efek dari penyimpanan durasi yang berbeda dari benih yang menghasilkan tingkat perkecambahan biji tertinggi. Prosedur penelitian meliputi uji kadar air dan protein, analisis kemurnian benih, sterilisasi, uji perkecambahan benih menggunakan warm germination test. Benih yang diproduksi pada tahun 2021 memiliki kadar air dan protein kasar yang lebih rendah masing-masing sebesar 13,26% dan 28,39%. Kemurnian benih berkisar antara 98,22% dan 99,62%. Tingkat perkecambahan biji rata-rata berada pada benih yang diproduksi tahun 2021 dengan rataan persentase benih berkecambah sebesar 39,33%. Hasil penelitian menunjukkan bahwa lama penyimpanan benih mempengaruhi kecepatan kecambah benih Indigofera sp. Benih yang disimpan kurang dari 1 tahun lebih cepat berkecambah daripada benih yang disimpan lebih dari 1 tahun., Indigofera sp. is a tropical legume that uses as forage and high-quality supplements because contained high nutritional value. In order to develop Indigofera plantation, it is necessary to identify a proper seed storage duration to reach high germination rate. The study aim was to evaluate the effect of different duration seeds storage on germination rate. Research procedures included water and protein content tests, seed purity analysis, sterilization, seed germination tests. The result showed that seeds production in 2019 had higher water content and crude protein 13.26% and 28.39%, respectively. The seed’s purity range were 97.98% and 99.62%. The highest seed rate was the seeds stored less than 1 year with an average percentage of germinated seeds of 39.33%. The length of seed storage duration affects the speed of sprouting seeds of Indigofera sp. Seeds stored for less than 1 year germinate faster than seeds stored for more than 1 year.
Keyword: daya kecambah, Indigofera sp., produksi benih, germination rate, seed production

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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