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.
Keyword: 

Judul: Unjuk Kinerja Instrumen HPLC UV/VIS untuk Analisis Kadar Gingerol dan Shogaol
Abstrak: Oleoresin jahe merupakan produk hasil ekstraksi jahe menggunakan pelarut organik, yang memiliki komponen utama berupa gingerol, shogaol, dan zingerone, yang memberikan rasa pedas pada jahe. Salah satu metode yang dapat digunakan untuk analisis senyawa gingerol dan shogaol adalah dengan High Performance Liquid Chromatography (HPLC). Metode analisis ini dapat digunakan secara rutin di laboratorium jika terlebih dahulu dilakukan unjuk kinerja instrumen HPLC untuk memastikan kinerja instrument tersebut sebelum digunakan untuk analisis. Penelitian ini bertujuan melakukan unjuk kinerja instrumen HPLC sebagai dasar untuk melakukan validasi metode analisis kadar gingerol dan shogaol pada oleoresin jahe merah. Metode penelitian yang dilakukan meliputi penentuan kondisi instrumen dan uji unjuk kinerja instrumen dengan menggunakan larutan standar 6-,8-,10-gingerol dan 6-shogaol sebagai sampel. Kondisi instrumen HPLC telah memenuhi kriteria kromatografi ideal. Hasil uji unjuk kinerja menunjukkan instrumen memiliki linieritas yang baik dengan R2 lebih dari 0,999 untuk masing-masing senyawa. Selain itu, instrumen juga memiliki presisi yang baik yaitu RSD kurang dari 2% untuk keempat senyawa, baik presisi luas area maupun waktu retensi. Limit deteksi instrumen (iLOD) yang diperoleh untuk 6-,8-,10-gingerol dan 6-shogaol berturut-turut yaitu 6,01; 25,67; 31,30; dan 5,40 µg/mL, sementara limit kuantifikasi instrumen (iLOQ) keempat senyawa berturut-turut yaitu 20,03; 85,57; 104,34; dan 18,01 µg/mL. Hasil unjuk kinerja instrumen HPLC dapat digunakan sebagai dasar untuk validasi metode analisis gingerol dan shogaol oleoresin jahe merah., The ginger oleoresin is a product of ginger extraction using organic solvents, which has the main components in the form of gingerol, shogaol, and zingerone, which give ginger a spicy taste. One method that can be used to analyze gingerol and shogaol compounds is High Performance Liquid Chromatography (HPLC). This analytical method can be used routinely in the laboratory if the performance of the HPLC instrument is first performed to ensure the performance of the instrument before being used for analysis. This study aims to demonstrate the performance test of the HPLC instrument as a basis for validating the method of analyzing the levels of gingerol and shogaol in red ginger oleoresin. The research method used included determining the condition and testing the performance of the instrument using standard solutions of 6-,8-,10-gingerol, and 6-shogaol as samples. The condition of the HPLC instrument met the ideal chromatographic criteria. The performance test results showed good linearity of the instrument with the coefficient of determination (R2) more than 0.999 for each compound. In addition, the instrument has good precision with RSD for the compounds was less than 2%, both precision in area and retention time. The instrument detection limits (iLOD) obtained for 6-,8-,10-gingerol and 6-shogaol were 6,01; 25,67; 31,30; and 5,40 g/mL, while the instrument quantification limits (iLOQ) for the four compounds were 20,03; 85,57; 104,34; and 18,01 g/mL. The results of the HPLC instrument performance test can be used as a basis for validation of the red ginger gingerol and shogaol oleoresin analysis methods.
Keyword: HPLC, performance test, gingerol, shogaol

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.
Keyword: