Judul: Kadar Total  Fenolik dan Aktivitas Antioksidan Ekstrak Buah Kapulaga Jawa (Amomum  compactum) dengan Perbedaan Metode dan Durasi Ekstraksi
Abstrak: Metode dan durasi ekstraksi akan memengaruhi kadar senyawa fenolik dan aktivitas antioksidan buah kapulaga jawa. Penelitian ini bertujuan mengukur dan membandingkan pengaruh metode dan durasi ekstraksi terhadap kandungan total fenolik dan aktivitas antioksidan dari ekstrak metanol buah kapulaga jawa asal Bogor. Buah kapulaga jawa diekstraksi dengan metode Continuous Shaking Extraction (CSE), Microwave Assisted Extraction (MAE), dan Ultrasonic Assisted Extraction (UAE) dengan perbedaan durasi ekstraksi. Kadar total fenolik diukur menggunakan metode Folin Ciocalteu dan aktivitas antioksidan diukur dengan metode ABTS dan CUPRAC. Kadar total fenolik metode ekstraksi MAE dengan durasi ekstraksi 3 menit (1,2633 mg EAG/g bobot kering) lebih tinggi dibandingkan dengan kadar total fenolik dari metode CSE dan UAE. Aktivitas antioksidan tertinggi metode ABTS (12,9332 µmol TE/g bobot kering) dan CUPRAC (38,1466 µmol TE/g bobot kering) didapatkan pada metode ekstraksi MAE durasi 3 menit. Kadar total fenolik setiap metode dan durasi ekstraksi menunjukkan korelasi yang positif terhadap aktivitas antioksidan., The effects of different extraction methods and durations on the levels of java cardamom fruit’s phenolic compounds and antioxidant activity were evaluated in this work. This research was aimed to measure and compare the effect of extraction method and duration on total phenolic content (TPC) and antioxidant activity in methanol extract of java cardamom fruit from Bogor. The sample was extracted by Continuous Shaking Extraction (CSE), Microwave Assisted Extraction (MAE), and Ultrasonic Assisted Extraction (UAE) with different duration. TPC was measured by the Folin Ciocalteu method and antioxidant activity was assayed using ABTS and CUPRAC methods. The TPC obtained from MAE for 3 minutes (1,2633 mg EAG/g dry weight) was the highest compared to those obtained from CSE and UAE methods. The highest antioxidant activity determined by ABTS (12,9332 µmol TE/g dry weight) and CUPRAC (38,1466 µmol TE/g dry weight) methods was obtained in MAE method with 3 minutes of extraction duration. The total phenolic content of each method and duration of extraction showed a positive correlation to the antioxidant activity.
Keyword: Antioxidant activity, Extraction method, Java cardamom, Phenolic

Judul: Total Phenolics, Flavonoids and Antioxidant Tests Variations in Extraction Methods and Solvents for Java Cardamom Fruit (Amomum compactum Sol. Ex Maton)
Abstrak: Metode dan pelarut ekstraksi dilaporkan mempengaruhi kadar senyawa metabolit sekunder dan aktivitas antioksidan buah kapulaga jawa. Penelitian ini bertujuan menentukan pengaruh metode dan jenis pelarut ekstraksi terbaik filtrat buah kapulaga jawa (Amomum compactum) berdasarkan kadar total fenolik, flavonoid dan aktivitas antioksidan. Buah kapulaga jawa diekstraksi dengan metode konvesional Refluks dan metode modern yaitu Microwave Assisted Extraction (MAE) dan Continuous Shaking Extraction (CSE) dengan pelarut Etanol, Metanol, dan Akuades. Hasil penelitian menunjukkan metode ekstraksi MAE pelarut Akuades memperoleh hasil tertinggi pada kadar fenolik yaitu 1,33, Extraction methods and solvents were reported to influence the levels of secondary metabolite compounds and antioxidant activity of Javanese cardamom fruit. This study aimed to determine the effect of the best extraction method and type of solvent for Javanese cardamom (Amomum compactum) fruit filtrate based on total phenolic, flavonoid and antioxidant activity levels. Javanese cardamom fruit is extracted using the conventional Reflux method and modern methods, namely Microwave Assisted Extraction (MAE) and Continuous Shaking Extraction (CSE) with the solvents Ethanol, Methanol, and Aquades. The results showed that the MAE extraction method using Aquades solvent obtained the highest results in phenolic content, namely 1.33
Keyword: antioxidant, cardamom, methods, secondary metabolites, solvents

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: