Judul: Phenolic total and Antioxidant Activity of 20 Genotype Temu Ireng in the Second Growing Season
Abstrak: Temu ireng (Curcuma aeruginosa Roxb) merupakan tanaman obat yang termasuk dalam famili Zingibaracae. Varietas unggul temu ireng harus stabil dan dapat tumbuh di berbagai kondisi lingkungan. Penelitian ini bertujuan untuk mengevaluasi total fenolik dan aktivitas antioksidan melalui interaksi antara genotipe dan lingkungan (GEI) dari 20 genotipe ekstrak etanol rimpang temu ireng yang ditanam pada musim tanam kedua dan tumbuh di tiga lingkungan agroekologi yang berbeda. Pengujian total fenolik menggunakan metode Folin Ciocalteu. Genotipe yang stabil pada pengujian total fenolik adalah G1, G2, G3, G4, G6, G12, G13, dan G16. Pengujian aktivitas antioksidan menggunakan metode DPPH. Genotipe yang stabil aktivitas antioksidannya adalah G1, G5, G6, G13, G16, dan G17. Genotipe unggul yang stabil di ketiga lokasi pada kedua parameter adalah G1, G6, G13, dan G16., Temu ireng (Curcuma aeruginosa RoxB) is a medicinal plant that belongs to the Zingibaracae family. Superior varieties of temu ireng should be stable and can be grown in various environmental conditions. This research was conducted to evaluate the total phenolic and antioxidant activity through Genotype by Environment Interaction (GEI) of 20 genotypes of ethanol extract temu ireng rhizomes that grown in the second growing season and grown in three different agro-ecological environments. Total phenolic was tested using the Folin-Ciocalteu method. The stable genotypes of total phenolic are G1, G2, G3, G4, G6, G12, G13, and G16. Antioxidant activity was tested using the DPPH method. The stable genotypes of antioxidant activity are G1, G5, G6, G13, G16, and G17. The stable superior genotypes in all three locations on both parameters are G1, G6, G13, and G16.
Keyword: DPPH, Stabilitas genotipe, Temu Ireng, Total Fenolik

Judul: Analisis Stabilitas Genotipe Temu Ireng dari Tiga Lokasi Berdasarkan Total Flavonoid, Saponin, dan Aktivitas Antioksidan
Abstrak: Temu ireng memiliki potensi yang baik untuk diaplikasikan secara luas sebagai obat tradisional, namun pemanfaatannya belum optimal karena tingkat produktivitasnya yang masih rendah. Tujuan penelitian yaitu menentukan genotipe tanaman temu ireng yang stabil dan memiliki aktivitas yang baik melalui pengaruh interaksi genotipe x lingkungan berdasarkan kandungan flavonoid, saponin, serta aktivitas antioksidan. Penelitian menggunakan 20 genotipe temu ireng sebagai sampel serta 2 varietas temu lawak kontrol yang ditanam pada 3 lokasi berbeda (Bogor, Cianjur dan Sukabumi). Pengujian total flavonoid dilakukan menggunakan metode AlCl3, sementara pengujian total saponin dilakukan menggunakan metode vanilin-asam sulfat, dan pengujian aktivitas antioksidan dilakukan menggunakan metode CUPRAC. Hasil penelitian menunjukkan adanya interaksi nyata antara faktor genotipe dan lingkungan pada taraf probabilitas 0%. Kandungan total flavonoid seluruh sampel pada ketiga lokasi tidak berbeda secara signifikan yang berkisar pada 0.02 hingga 0.04 mg QUE/g berat basah dan seluruh sampel merupakan genotipe stabil. Genotipe G1 dan G6 menghasilkan aktivitas antioksidan tertinggi secara signifikan pada ketiga lokasi sebesar 11.501 dan 10.201 mol TE/g berat basah, sementara seluruh sampel kecuali kedua genotipe tersebut merupakan genotipe stabil. Genotipe G5 mengandung total saponin tertinggi secara signifikan pada ketiga lokasi sebesar 146.369 mg DE/g berat basah, sementara genotipe G1, G2, G15, dan G16 merupakan genotipe stabil., Temu ireng has good potential to be widely applied as traditional medicine, but its’ utilization is not yet optimal due to its’ low productivity. The purpose of this study is to determine stable genotypes of temu ireng which had good activity through genotype and environmental interactions based on the content of flavonoids, saponins, and antioxidant activity. This study uses 20 genotypes of temu ireng as samples and 2 varieties of temu lawak as controls which were planted in 3 different locations (Bogor, Cianjur and Sukabumi). Total flavonoid testing was carried out using the AlCl3 method, while total saponin testing was carried out using the vanillin-sulfuric acid method and the antioxidant activity testing was carried out using the CUPRAC method. The results showed that there was a significant interaction between genotype and environmental factors at probability level of 0%. The total flavonoid content of all samples at the three locations did not differ significantly between 0.02 to 0.04 mg QUE/g fw, and all samples were stable genotypes. Genotypes G1 and G6 produced the highest antioxidant activity significantly at the three locations at 11.501 and 10.201 mol TE/g fw, while all samples except the two genotypes were stable genotypes. Genotype G5 had the highest total saponin content significantly at the three locations at 146.369 mg DE/g fw, while genotypes G1, G2, G15, and G16 were stable genotypes.
Keyword: antioxidant, flavonoid, genotype x environment interaction, saponin, temu ireng

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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