Judul: Evaluation of Tea (Camellia sinensis (L.) O. Kuntze) Picking Methods for Producing Green Tea in Negara Kanaan Tea Plantation, Bandung, West Java.
Abstrak: Evaluasi Metode Pemetikan Teh (Camellia sinensis (L.) O. Kuntze) Untuk Memproduksi Teh Hijau di Perkebunan Teh Negara Kanaan, Bandung, Jawa Barat. Dibimbing oleh AHMAD ZAMZAMI dan PURWONO. Kegiatan magang dilaksanakan pada bulan Januari – April 2021 di PT. Ratnapura Bianka. Tujuan kegiatan magang adalah meningkatkan pengetahuan dan pengalaman pada aspek pemetikan daun teh, menambah dan mengembangkan keterampilan dalam budi daya tanaman teh, dan mengevaluasi metode pemetikan teh dalam meningkatkan kualitas dan kuantitas pucuk teh. Metode yang digunakan adalah metode langsung dan tidak langsung. Hasil pengamatan tinggi bidang petik, lebar bidang petik, dan potensi pucuk menunjukkan semakin tinggi umur pangkas, tanaman akan semakin tinggi, bidang petik akan semakin lebar, dan persentase peko menurun. Analisis petik pada pemetikan secara semi-mekanis lebih baik dibandingkan mekanis untuk memperoleh jenis petikan medium. Analisis pucuk yang memenuhi syarat (PMS) pada pemetikan secara semi-mekanis lebih tinggi dibandingkan pemetikan secara mekanis. Gilir dan hanca petik pada areal semi-mekanis lebih cepat dibandingkan dengan areal pemetikan mekanis. Kapasitas pemetik pada pemetikan semi-mekanis lebih sedikit dibandingkan mekanis dan tidak dipengaruhi oleh umur, lama pengalaman kerja, dan gender pemetik. Kekurangan tenaga petik pada areal semi-mekanis lebih sedikit dibandingkan areal mekanis dengan total kekurangan 24 orang. Pertumbuhan pucuk pada areal semi-mekanis lebih cepat dibandingkan areal mekanis. Kata kunci: alat petik, gilir petik, kualitas pucuk, pertumbuhan pucuk, tenaga pemetik, Internship activities carried out in Januari – April 2021 at PT. Ratnapura Bianka. The aim of the internship is to increase knowledge and experience on aspect of tea leaf picking, increase and develop skills in tea cultivation, and evaluate tea picking methods in improving the quality and quantity of tea shoots. The methods used are direct and indirect methods. The results of observations of height, width of the picking area, and the potency of shoots showed that the older the age of the pruning make the plants get taller, the picking area getting wider, and the percentage of peko is decreasing. The shoots analysis on semi-mechanical is better than mechanical for obtaining medium type of picking. The analysis of shoots that qualify (PMS) in semi-mechanical is higher than mechanical. The picking rotation in semi-mechanical is faster than the mechanical. The picking capacity in semi-mechanical is lower than mechanical and is not affected by age, length of work experience, and gender of picker. The shortage of picking power in the semi-mechanical area is lower than the mechanical area with a total shortage of 24 people. Shoot growth in the semi-mechanical area was faster than in the mechanical area. Key words: picking tool, picking rotation, picking power, shoot quality, shoot growth
Keyword: picking tool, picking rotation, picking power, shoot quality, shoot growth

Judul: Management of Tea Tree Plucking (Camellia sinensis (L.) O. Kuntze) at Wonosari Estate, PT Perkebunan Nusantara XII, Malang
Abstrak: Pemetikan merupakan kegiatan pemanenan pucuk dan daun teh yang dapat mempengaruhi kualitas dan kuantitas pucuk teh. Kegiatan magang dilaksanakan pada bulan Februari – Juni 2022 di PT Perkebunan Nusantara XII. Tujuan kegiatan magang adalah meningkatkan pengetahuan, keterampilan, pengalaman kerja secara teknis di lapangan dan manajerial pada perkebunan teh, serta mengetahui dan memahami pengelolaan pemetikan terhadap hasil pucuk teh dengan mutu yang baik dan produksi yang tinggi. Metode yang digunakan adalah metode langsung dan tidak langsung. Hasil pengamatan tinggi bidang petik dan lebar bidang petik menunjukkan hasil berbanding lurus dengan umur pangkas, bertambahnya umur pangkas maka tinggi bidang petik dan diameter bidang petik lebih besar. Perkembangan pucuk pada pemetikan manual lebih cepat, persentase pucuk peko menurun dengan bertambahnya umur pangkas. Hanca dan gilir petik pada pemetikan manual lebih kecil. Analisis petik pada pemetikan manual lebih baik untuk memperoleh jenis petikan medium. Analisis pucuk yang memenuhi syarat (MS) pada pemetikan manual lebih tinggi dibandingkan pemetikan mesin. Tenaga pemetik di lapang dari metode manual dan mesin masih kurang. Kapasitas pemetik pada metode pemetikan mesin lebih besar. Kapasitas pemetik dapat dipengaruhi oleh umur, lama pengalaman kerja, dan gender., Picking is an activity of harvesting tea shoots and leaves that can affect the quality and quantity of tea shoots. Internship activities are carried out in February – June 2022 at PT Perkebunan Nusantara XII. The purpose of the internship is to increase knowledge, skills, technical and managerial work experience in tea plantations, as well as to know and understand the management of picking tea shoots with good quality and high production. The method used is a direct and indirect method. The results of observations of the height of the picking field and the width of the picking field show that the results are directly proportional to the age of the pruning, increasing age of the pruning means that the height of the picking field and the diameter of the picking field are larger. Shoot development in manual picking was faster, the percentage of peko shoots decreased with increasing pruning age. Chopping and rotating picks in manual picking is smaller. Pick analysis on manual plucking is better for obtaining medium plucking types. Analysis of eligible shoots (MS) in manual picking is higher than that of machine picking. Picking power in the field from manual and machine methods is still lacking. The picking capacity of the machine picking method is greater. Picking capacity can be influenced by age, length of work experience, and gender.
Keyword: plucking tools, picking method, shoot development, labor

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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