Judul: Palm Oil (Elaeis guineensis Jacq.) Harvest Management at Kebun Rambutan PTPN III, Serdang Berdagai, North Sumatera
Abstrak: Kelapa sawit merupakan komoditas dengan nilai ekonomis yang tinggi karena dapat menghasilkan minyak kelapa sawit yang berguna banyak. Panen merupakan salah satu bagian produksi di perkebunan kelapa sawit yang menghubungkan kebun dan pabrik kelapa sawit seperti melepaskan buah dari pohon serta mengangkut hasil ke PKS. Kegiatan magang dilaksanakan di Kebun Rambutan, PTPN III, Sumatera Utara, dari bulan Januari hingga April 2020. Kegiatan ini bertujuan untuk melatih keterampilan motorik, memperoleh pengalaman dalam bidang perkebunan kelapa sawit, dan mempelajari manajemen sistem panen yang tepat di perkebunan kelapa sawit. Aspek yang diamati berupa perencanaan, pelaksanaan, dan evaluasi panen. Hasil pengamatan diuji menggunakan metode kuantitatif dan kualitatif serta uji statistik menggunakan uji t-student dan uji korelasi. Rata–rata rotasi panen belum memenuhi standar perusahaan. Realisasi jumlah tenaga panen tidak sesuai dengan taksasi kebutuhan, tetapi kekurangan ini masih dapat ditutupi dengan output panen yang lebih besar oleh setiap pemanen. Kegiatan taksasi panen sudah sesuai standar perusahaan yaitu dengan varian dibawah 5 %. Penggunaan alat pelindung diri (APD) pemanen sudah cukup baik, pemakaian kacamata pelindung harus ditingkatkan. Pemotongan tangkai buah menjadi berbentuk huruf V harus lebih ditingkatkan. Mutu buah masak masih di bawah standar perusahaan sebesar 97.05 % dari 100 % yang ditargetkan. Rata-rata muatan pengangkutan TBS masih melebihi kapasitas truk. Uji korelasi menunjukkan persentase korelasi yang rendah antara curah hujan dengan produktivitas.
Keyword: kelapa sawit, angka kerapatan panen, produktivitas, curah hujan

Judul: Palm Oil (Elaeis guineensis Jacq.) Harvest Management at Kebun Rambutan PTPN III, Serdang Berdagai, North Sumatera
Abstrak: Palm oil is a commodity with high economic value because it can produce oil that has many use. Harvest is one part of the production system in oil palm plantations that connects oil palm plantations and factory such as harvesting fruit from trees and transporting it to the factory. The internship was carried out at Kebun Rambutan, PTPN III, North Sumatera, from January 2020 to April 2020. This activity aims to train motoric skills, gain experience in the field, and learn proper management of the harvest system in oil palm plantation. Things that will be observed were harvest planning, harvest implementation, and harvest evaluation. Data analysis method used were quantitative and qualitative methods and statistical analyzed by the t–student test and correlation test. The harvest rotation have not yet meet the company standard. Realization of the amount of labor needed to harvest is not corresponding with the estimation, but this shortage can still be covered by the large output of each harvester. Harvesting activities are suitable with the company standards, which is variant below 5 %. The use of personal protective equipment (PPE) is good enough, the use of protective goggles must be increased again. Cutting fruit stems into the shape of the letter V must be increased. The quality of the fruit was 97.05 % out of 100 %, which is below the company standards. The average load of the transported-fruit still exceeds the capacity of the transport. Correlation test shows that there is a low correlation pecentage between productivity and rainfall.
Keyword: oil palm, angka kerapatan panen, produktivitas, curah hujan

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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