Judul: Kendali Mutu Jahe Menggunakan Sidik Jari Kromatografi Cair Kinerja Tinggi dan Analisis Multivariat
Abstrak: Ginger is known to have pharmacology effect such as antioxidant, antiinflamation, and anticancer. The rhizome of ginger is widely used as component in various herbal medicine preparations so that needed some methods to guarantee its quality and pharmacology effect. The aim of this research was to evaluate the quality of gajah ginger rhizome by antioxidant activity assay, high performance liquid chromatography (HPLC) fingerprint pattern examination, major compound content determination, and also quality model establishment of ginger ethanol extracts from 3 areas, that is Ponorogo, Tangerang, and Bogor. All samples were indeed potential as very strong antioxidant. The result of HPLC analysis showed 6-, 8-, and 10-gingerol, also 6-shogaol as dominant compounds. Grouping based on content of dominant compounds and HPLC fingerprint that used principal component analysis resulted group I (Tangerang), group II (Ponorogo), and group III (Bogor). The quality model that was formed using partial least square discriminant analysis showed that antioxidant activity of ginger was more defined by composition of all compounds than by its dominant compounds.
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Judul: Spektroskopi FTIR dan metode pengenalan pola kimia untuk diferensiasi tanaman jahe
Abstrak: Ginger (Zingiber officinale) is one of raw materials the traditional medicine. Ginger consist of three type of varieties, however from three type of ginger varieties only two varieties which often used as a raw materials herbal medicine. Usage of ginger as a raw material herbal medicine can be falsified by mixing betwen ginger varieties or also with alpine galangal. Therefore it’s require a differentiation technique of ginger to control the quality of raw material herbal medicine. FTIR spectrum of the ginger and multivariate analysis can be used to differentiation. Multivariate analysis that used is PCA (Principal Component Analysis) and PLSDA (Partial Least Square Discriminant Analysis). PCA method used in the normal spectrum can classify the samples into five different classification classes. However, PCA methods have not been able to separate pure samples of JE, JG, and JM. PLSDA method used in the second derivative spectrum. This Method produces R2 prediction value for L, JE, JG, JM, JM + JE, JM + JG, and JM + L respectively, 0.9575, 0.9518, 0.9672, 0.9642, 0.7591, 0.7804 and 0.8222
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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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