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: Management of Plucking Tea Plants (Camellia sinensis (L.) O. Kuntze) Rancabali Plantation, PTPN VIII, Bandung, West Java
Abstrak: Pemetikan merupakan kegiatan pemanenan pucuk tanaman teh yang dilakukan secara manual maupun mekanis dan dapat mempengaruhi kualitas serta kuantitas pucuk. Kegiatan magang dilaksanakan pada bulan Januari-Mei 2021 di Kebun Rancabali, PT Perkebunan Nusantara VIII, Bandung, Jawa Barat. Kegiatan magang bertujuan mempelajari budidaya teh secara teknis dan manajemen, khususnya mengenai pengelolaan pemetikan teh untuk mendapatkan pucuk teh dengan mutu yang baik dan produksi yang tinggi. Metode yang dilaksanakan selama magang, yaitu bekerja secara langsung di lapangan pada berbagai level pekerja dengan aspek khusus pemetikan pucuk dan mengumpulkan data sekunder dari arsip kantor induk, kantor afdeling, dan studi pustaka. Hasil pengamatan tinggi bidang petik, diameter bidang petik, tebal daun pemeliharaan, dan potensi hasil pucuk menunjukkan semakin tua umur pangkas maka bidang petik akan semakin tinggi, bidang petik semakin lebar, tebal daun pemeliharaan semakin tipis, dan persentase pucuk peko menurun. Tinggi bidang petik dipengaruhi oleh kemiringan lahan, semakin curam maka tinggi bidang petik semakin pendek. Laju perkembangan pucuk semakin lambat seiring bertambahnya umur pangkas. Hanca petik mesin lebih tinggi dibandingkan gunting petik, dan pemetikan delay leaf. Gilir petik gunting dan delay leaf lebih cepat dibandingkan mesin. Tenaga pemetik di lapangan masih kurang jika dilihat dari hasil perhitungan untuk semua metode pemetikan. Pemetikan mesin menghasilkan mutu yang lebih baik dibandingkan gunting petik. Hasil analisis pucuk masih dibawah standart (38,94% dari standar 60%) memerlukan peningkatan mutu pucuk dengan memperhatikan teknis pemetikan. Kata Kunci: gilir petik, Plucking is an activity of harvesting tea plant shoots that is carried out manually or mechanically and can affect the quality and quantity of shoots. Internship activities carried out in January-May 2021 at Rancabali Plantation, PT Perkebunan Nusantara VIII, Bandung, West Java. The internship activity aims to learn tea cultivation technically and management, especially regarding the management of tea picking to get tea shoots with good quality and high production. The method implemented during the internship is working directly in the field on various worker level with special aspects on tea plucking and collecting secondary data from the archives of the main office, division office, and references. The results showed that the height of the plucking area, diameter of the plucking area, thickness of maintenance leaves, and shoot yield potential showed that the older of the pruning age having the higher of plant height, the wider of plucking field, the thinner of maintenance leaf, and the decrease in the percentage of active bud shoots. The height of the plucking field is influenced by the slope of the land, the steeper it is, the shorter the height of the plucking field. The rate of shoot development slows down as the plant ages. Plucking mechine output is higher than plucking scissors, and plucking leaf delay. Scissor plucking rotation and delay leaf are faster than that by machines. The plucking worker in the field is still less number than the calculation for all the plucking methods. Plucking by machine produces better quality than plucking scissors. The results of the shoot quality analysis still below the standard (38,94% of standard 60%) indicate require an increase in shoot quality by taking care the plucking management.
Keyword: plucking method, plucking rotation, shoot quality

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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