Judul: Peningkatan Kandungan Zat Besi, Total Fenolik, dan Aktivitas Antioksidan Bayam Hijau (Amaranthus viridis L.) dengan Pupuk Maggot (Black Soldier Fly).
Abstrak: Bayam hijau (Amaranthus viridis L.) merupakan tanaman yang mengandung zat besi yang tinggi, senyawa metabolit sekunder seperti flavonoid, antioksidan, dan fenolik yang bermanfaat untuk penyakit degeneratif. Penelitian ini bertujuan mengetahui pertumbuhan tinggi tanaman, jumlah daun, kandungan zat besi, total fenolik, dan aktivitas antioksidan tanaman bayam menggunakan pupuk maggot (Black Soldier Fly). Kandungan zat besi diukur menggunakan metode ICP-OES, kadar total fenolik diukur menggunakan metode Folin-Ciocalteu, dan aktivitas antioksidan diukur menggunakan metode DPPH. Hasil penelitian menunjukkan perlakuan 2 (2:8) memiliki nilai kandungan zat besi tertinggi sebesar 13,73 ± 0,0419a mg/100g BK dan aktivitas antioksidan tertinggi sebesar 18,61 ± 0,0644a μmol TE/100g BK sedangkan perlakuan 1 (1:9) memiliki pertumbuhan tertinggi rata-rata sebesar 259,47 mm, jumlah daun sebesar 17,53 lembar, dan bobot basah sebesar 288 gr serta nilai fenolik tertinggi sebesar 273,55 ± 5,6480a mg GAE/100g BK. Penggunaan pupuk maggot memberi nilai pertumbuhan, jumlah daun, bobot basah, kandungan zat besi, total fenolik, dan aktivitas antioksidan yang lebih tinggi dibandingkan pupuk organik (kandang)., Green spinach (Amaranthus viridis L.) is a plant that contains high iron, secondary metabolite compounds such as flavonoids, antioxidants, and phenolics which are beneficial for degenerative diseases. This study aimed to determine the growth of plant height, number of leaves, iron content, total phenolic, and antioxidant activity of spinach plants using maggot fertilizer (Black Soldier Fly). Iron content was measured using ICP-OES method, total phenolic content was measured using Folin-Ciocalteu method, and antioxidant activity was measured using DPPH method. The results showed that treatment 2 (2:8) had the highest iron content values of 13,73 ± 0,0419a mg/100 gr BK and the highest antioxidant activity of 18,61 ± 0,0644a μmol TE/100 gr BK while treatment 1 (1:9) had the highest average growth of 259,47 mm and 17,53 leaves, and wet weight of 288 gr and the highest phenolic value of 273,55 ± 5,6480a mg GAE/100 gr BK. The use of maggot fertilizer gave higher values of growth, number of leaves, wet weight, iron content, total phenolic, and antioxidant activity compared to organic (manure)
Keyword: antioxidant, iron, phenolic, spinach

Judul: Pengaruh Pemberian Pupuk Kasgot Terhadap Pertumbuhan, Kadar Zat Besi, dan Kapasitas Antioksidan Bayam Hijau (Amaranthus  viridis L.)
Abstrak: Kualitas bayam hijau dapat dipengaruhi oleh pupuk karena berperan penting dalam menyediakan nutrisi. Penelitian ini bertujuan menentukan pengaruh pemberian pupuk kasgot terhadap pertumbuhan, kadar zat besi, dan kapasitas antioksidan bayam hijau. Metode penelitian dilakukan dengan rancangan acak lengkap yang terdiri dari tiga taraf dosis pemberian pupuk kasgot per 12 m2 lahan tanam yaitu 6 kg (dosis 1), 9 kg (dosis 2), dan 12 kg (dosis 3). Kadar zat besi daun bayam hijau diukur menggunakan ICP-OES, ekstraksi dilakukan dengan maserasi menggunakan etanol 96%, dan kapasitas antioksidan diukur dengan metode FRAP. Hasil penelitian menunjukkan perlakuan dosis 2 memiliki nilai kadar zat besi tertinggi sebesar 150,91 mg/100 g bobot kering dan kapasitas antioksidan tertinggi sebesar 112,96 ± 3,82 μM TE/g ekstrak, sedangkan perlakuan dosis 3 memiliki pertumbuhan tertinggi dengan rata-rata sebesar 59,67 cm, jumlah daun sebesar 30 lembar, dan bobot basah sebesar 47,33 g. Penggunaan pupuk kasgot mampu meningkatkan pertumbuhan tanaman, kadar zat besi, dan kapasitas antioksidan tanaman bayam hijau dengan konsentrasi pemupukan yang sesuai.
Keyword: Antioxidant, Green Spinach, Growth, Iron, Maggot

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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