Judul: Manajemen Pemupukan Kelapa Sawit (Elaeis guineensis Jacq) di Kebun Aek Nabara PT Supra Matra Abadi, Labuhan Batu, Sumatera Utara
Abstrak: Aktivitas magang sudah tingkatkan pengetahuan tentang budidaya kelapa sawit dari segi teknis ataupun manajerial. Aktivitas magang dilaksanakan pada bulan Januari sampai Mei 2021 di Kebun Aek Nabara PT Supra Matra Abadi. Tujuan khusus aktivitas magang buat menekuni manajemen pemupukan tanaman kelapa sawit. Pengamatan pemupukan mengamati prinsip 5T (tepat waktu, tepat dosis, tepat tempat, tepat cara, tepat jenis) serta taksasi produksi. Hasil pengamatan di lapangan menampilkan secara umum pemupukan di Kebun Aek Nabara telah mempraktikkan kaidah 5T dengan baik. Hasil pengamatan tepat waktu, tepat dosis, tepat tempat, tepat cara, tepat jenis, serta taksasi produksi telah berjalan dengan baik menurut standar yang diresmikan perusahaan., Internship had increased the knowledge about oil palm cultivation in terms of technical and managerial. The internship activity were held from January to May 2021 at Aek Nabara PT Supra Matra Abadi. The specific purpose of the internship is to study fertilization management on oil palm. Fertilizing observations were carried out based on the 5R principle (right time, right dose, right place, right way, right type) and work performance. The observations in the field that fertilization at Aek Nabara Estate has applied the 5R principle well. The observations activities in right time, right dose, right place, right way, right type and production improvements has applied well following the company standard.
Keyword: kelapa sawit, ketepatan, pemupukan, prinsip 5T, 5T principle, accuracy, fertilization, palm oil

Judul: Manajemen Pemupukan Tanaman Kelapa Sawit (Elaeis guineensis Jacq.) di Unit Bekri PT Perkebunan Nusantara VII Lampung
Abstrak: Kegiatan magang telah meningkatkan pengetahuan tentang budidaya kelapa sawit dari segi teknis maupun manajerial. Kegiatan magang dilaksanakan pada bulan Januari sampai dengan April 2020 di Kebun Unit Bekri PT Perkebunan Nusantara VII Lampung. Tujuan khusus kegiatan magang untuk mempelajari manajemen pemupukan tanaman kelapa sawit. Pengamatan pemupukan mengamati prinsip 5T (tepat waktu, tepat dosis, tepat tempat, tepat cara, tepat jenis) dan prestasi kerja. Hasil pengamatan di lapangan menunjukkan bahwa secara umum pemupukan di Kebun Unit Bekri sudah menerapkan kaidah 5T dengan baik. Hasil pengamatan tepat waktu, tepat tempat, tepat jenis, dan prestasi kerja sudah berjalan dengan baik mengikuti standar yang ditetapkan perusahaan. Pengamatan tepat dosis dan tepat cara sudah berjalan cukup baik, namun masih perlu ditingkatakan nilai ketepatannya > 95.00% pada pemupukan berikutnya.
Keyword: kelapa sawit, ketepatan, pemupukan, prinsip 5T

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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