Judul: Perlakuan Naungan dan Pupuk Nitrogen Terhadap Pertumbuhan dan Fisiologis Tanaman Gandarusa (Justicia gendarussa Burm. F.)
Abstrak: Gandarusa merupakan tanaman semak yang belum banyak dibudidayakan padahal berpotensi menjadi bahan obat-obatan herbal. Penelitian ini bertujuan menganalisis pengaruh naungan dan pupuk nitrogen terhadap pertumbuhan dan fisiologis tanaman gandarusa. Tahapan uji yang dilakukan adalah uji pertumbuhan, fotosintesis, klorofil, dan karbohidrat daun gandarusa. Rancangan percobaan yang dipakai adalah desain split-plot dengan petak utama merupakan naungan (S) (0% (S0), 25% (S25), dan 50% (S50)) dan anak petak merupakan pupuk nitrogen (N) (0 (N0), 90 (N90), 180 (N180), dan 270 (N270) kg/ha). Hasil penelitian menunjukkan interaksi antara naungan dan pemupukan hanya pada jumlah cabang (JC) namun tidak pada tinggi tanaman (TT) dan jumlah daun (JD). Perlakuan S0 dan N270 merupakan perlakuan terbaik pada proses pertumbuhan dengan nilai tertinggi pada TT (39,8 cm (S0) dan 34,3 cm (N270)), JD (60,8 helai (S0) dan 45,8 helai (N270)), dan JC (11,4 cabang (S0) dan 10,8 cabang (N270)). Laju fotosintesis tertinggi didapatkan pada kombinasi perlakuan naungan 0% dan pupuk N 0 kg/ha (S0N0) dengan nilai 23,91 μmol CO2 m-2s -1 . Adapun, perlakuan dengan kadar klorofil total tertinggi didapat pada S25 (0,902 mg/g) dan N270 (0,832 mg/g). Serta kadar karbohidrat per bobot basah daun tertinggi didapatkan pada S0 (72,88 mg/g) dan N270 (76,25 mg/g).
Keyword: gandarusa, nitrogen fertilizer, and shading

Judul: Combination of Manure and NPK Fertilizer to Growth, Photosynthesis, Chlorophyll and Sugar Content In Gandarusa Plants
Abstrak: Gandarusa (Justicia gendarussa Burm. F.) merupakan salah satu tanaman yang digunakan sebagai obat tradisional di Indonesia. Budidaya yang tepat diperlukan untuk meningkatkan biomassa tanaman gandarusa. Penelitian bertujuan menentukan metode budidaya untuk meningkatkan biomassa melalui pemupukan serta pengaruhnya terhadap pertumbuhan, fotosintesis, kandungan klorofil dan kandungan gula pada tanaman gandarusa. Penelitian menggunakan enam kelompok perlakuan, yaiu kontrol berupa media tanah (T1). pupuk kandang (T2), pupuk NPK (T3), 50% pupuk kandang dan 50% pupuk NPK (T4), 50% pupuk kandang dan 10% pupuk NPK (T5), serta 50% pupuk NPK dan 10% pupuk kandang (T6). Parameter pengamatan pertumbuhan meliputi tinggi tanaman, jumlah daun, jumlah cabang dan bobot tanaman, sementara parameter fotosintesis yaitu laju fotosintesis, konduktivitas stomata, kandungan CO2 intraseluler dan laju transpirasi. Kandungan klorofil dan gula masing-masing ditentukan dengan persamaan Arnon’s dan metode fenol-asam sulfat. Secara keseluruhan, perlakuan kombinasi 50% pupuk kandang dan 10% pupuk NPK merupakan perlakuan yang paling baik karena menghasilkan biomassa tanaman gandarusa tertinggi., Gandarusa (Justicia gendarussa Burm. F.) is one of the plants that are being used as traditional medicine in Indonesia. Proper cultivation is needed to increase the biomass of gandarusa. The research aims to determine the best cultivation method to increase biomass through fertilization and its effect on growth, photosynthesis, chlorophyll content and sugar content in gandarusa. The research used six treatment groups, namely control in the form of soil media (T1), manure (T2), NPK fertilizer (T3), 50% manure and 50% NPK fertilizer (T4), 50% manure and 10% NPK fertilizer (T5), as well as 50% NPK fertilizer and 10% manure. Growth observation parameters included plant height, number of leaves, number of branches and plant weight, while photosynthetic parameters were photosynthesis rate, stomatal conductivity, intracellular CO2 content and transpiration rate. The content of chlorophyll and sugar were determined by Arnon's equation and the phenol-sulfuric acid method, respectively. Overall, the combination of 50% manure and 10% NPK fertilizer was the best cultivation method because it produced the highest amount of gandarusa biomass.
Keyword: chlorophyll, fertilizer, growth, photosynthesis, sugar

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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