Judul: Kendali Mutu Daun Kumis Kucing (Orthosiphon stamineus) Menggunakan Pengolahan Citra Dan Teknik Pengenalan Pola Secara Kemometrik
Abstrak: Kumis kucing (Orthosiphon stamineus) is one of medicinal plants that widely used as a traditional medicine. This research aims to use the spectral imaging as a method to quality control of kumis kucing leaves with diversity of quality based on the different from 3 areas of the plant that is correlated with the intensity of leaf color and pattern recognition techniques combine with chemometric PCA and PLSDA. Analysis of thin-layer chromatography with software image J shows the difference of quality active compound kumis kucing from 3 areas is Cigombong, Nagrak, and Pacet. The best standard model and polynomial using polynomial orde 2 (term 7). Samples from Nagrak have better quality than other areas. Model PCA produces 97% of the value of PC 1 and PC 2 3%. PLSDA analysis produces 3 models, namely models PLSDA from Cigombong (R2 kalibrasi= 0.8395, R2 prediksi= 0.8051), Nagrak (R2 kalibrasi= 0.8185, R2 prediksi= 0.7779), dan Pacet (R2 kalibrasi= 0.7603, R2 prediksi= 0.7392). This model has successfully predicted the kumis kucing leaves to approach the quality of different areas of the plant.
Keyword: Bogor Agricultural University, spectral imaging, quality control, PLSDA, PCA, kumis kucing

Judul: Aplikasi Kemometrik Untuk Kendali Mutu Simplisia Kumis Kucing (Orthosiphon Aristatus)
Abstrak: Kumis kucing (Orthosiphon aristatus) adalah tanaman yang banyak digunakan sebagai obat herbal. Mutu tanaman obat dipengaruhi oleh berbagai faktor, salah satunya adalah daerah asal tanaman. Penelitian ini mengelompokkan spektra FTIR kumis kucing dari 5 daerah berbeda menggunakan principle component analysis (PCA) dan partial least square discriminant analysis (PLSDA) serta membuat model prediksi flavonoid total menggunakan partial least square (PLS). Sampel dari daerah Nagrak memiliki mutu yang lebih baik daripada 4 daerah lainnya berdasarkan analisis kadar air, kadar abu, rendemen ekstrak, fenol total, flavonoid total, dan kadar sinensetin. Sampel dari 5 daerah memiliki pola kromatogram KLT yang cukup berbeda, tetapi memiliki aktivitas antibakteri yang sama. PCA dengan total keragaman 73% mampu mengelompokkan sampel bermutu tinggi dan rendah. Model PLSDA berhasil memprediksi sampel uji berdasarkan kelompok mutu dan daerah asal sampel. Pembuatan model prediksi flavonoid total dengan PLS menghasilkan R2 kalibrasi, R2 prediksi, RMSEC, dan RMSEP masing-masing sebesar 0.7765, 0.5066, 0.4003, dan 0.6157. Hasil penelitian ini menunjukkan bahwa spektra FTIR dan kemometrik dapat digunakan untuk kendali mutu kumis kucing.
Keyword: fenolik, flavonoid, kemometrik, kendali mutu, kumis kucing

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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