Judul: Ornamental Bedding Plants Management of Vinca (Catharanthus roseus) and Celosia (Celosia argentea) in PT. Bina Usaha Flora, Cianjur, West Java
Abstrak: Kegiatan magang dilaksanakan pada bulan Januari – Mei 2021 di PT. Bina Usaha Flora, Cianjur, Jawa Barat. Kegiatan magang bertujuan meningkatkan pengetahuan dan keterampilan mengenai teknik pengelolaan produksi usaha tanaman hias, terutama tanaman hias hamparan, termasuk jadwal produksi mulai dari persiapan tanam hingga siap panen, dan kriteria panen tanaman Celosia argentea dan Catharanthus roseus. Kegiatan tambahan dalam magang yaitu mempelajari pengaruh aplikasi retardan paclobutrazol pada Celosia argentea untuk menghasilkan tanaman yang pendek dan seragam. Ketinggian Celosia argentea bisa mencapai 100 cm yang membuat tanaman mudah rebah dan kesulitan dalam transportasi. Pengukuran pertumbuhan pada vinca meliputi tinggi tanaman, jumlah cabang sekunder, jumlah bunga, dan diameter bunga. Pengukuran pertumbuhan Celosia argentea meliputi tinggi tanaman, jumlah daun, jumlah cabang sekunder, jumlah ruas, jumlah bunga, dan ukuran bunga. Kegiatan budidaya tanaman hias yang dilakukan meliputi persiapan media semai, persemaian, persiapan media tanam, pindah tanam, penyiraman, pemumpukan, pengendalian hama penyakit, dan panen. Hasil pengamatan kriteria panen tanaman Vinca menunjukkan hasil yang sesuai dengan kriteria perusahaan. Aplikasi retardan paclobutrazol pada konsentrasi 10 ppm dengan cara disiram pada media efektif dapat mengurangi tinggi tanaman Celosia dan memenuhi kriteria yang diinginkan perusahaan., The internship activities was carried out in January – May 2021 at PT. Bina Usaha Flora, Cianjur, West Java. This aims of the internship is to increase knowledge and skills about production management and cultural techniques in ornamental plants, particularly of bedding plants, including production schedule from planting preparation until ready to harvest, the harvest criteria of Celosia argentea and Catharanthus roseus. An additional activity was conducted during the internship, i.e. to study the effects of retardant paclobutrazol application in Celosia argentea in order to produce short and compact plants. Celosia argentea height could reach 100 cm which make them prone to lodging and more difficult to transport. Growth measurement on Vinca included plant height, number of branches, number of flowers, and diameter of flowers to determine harvest criteria. Growth measurement on Celosia argentea included plant height, number of leaves, number of branches, number of internodes, number of flowers, and diameter of flowers. Cultivation activities include preparation of nursery media, nurseries, preparation of planting media, transplanting, watering, fertilizing, controlling pests and diseases, and harvest. The harvest criteria of Vinca has been conducted in accordance with the company’s criteria. Retardant paclobutrazol application in Celosia at 10 ppm concentration with soil drench application is effective to produce short and compact plants and I have met the company’s criteria.
Keyword: Celosia, Harvest criteria, Retardant, Vinca

Judul: Production Management of Peperomia (Peperomia sp.), Begonia (Begonia sp.), Bromelia (Neoregelia schultesiana), and Hortensia (Hydrangea macrophylla) in PT Melrimba Mitra, West Java
Abstrak: Kegiatan magang dilaksanakan pada bulan Maret – Juli 2021 di PT. Melrimba Mitra, Kab. Bogor, Jawa Barat. Kegiatan magang bertujuan untuk meningkatkan pengalaman, wawasan, serta kemampuan teknis dalam pengelolaan tanaman hias khususnya peperomia, bromelia, begonia sebagai tanaman hias pot dan hortensia sebagai tanaman hias lanskap. Kegiatan teknis pengelolaan tanaman hias mencakup jadwal produksi mulai dari persiapan tanam hingga siap panen dan kriteria panen tanaman. Pengamatan tanaman Peperomia obtusifolia, Neoregelia schultesiana, dan Hydrangea macrophylla meliputi jumlah daun dan tinggi tanaman. Pengukuran tanaman Peperomia argyreia dan Peperomia caperata meliputi jumlah tunas. Pengukuran Begonia ‘orococo’ meliputi panjang daun, lebar daun, dan jumlah daun. Kegiatan budi daya tanaman hias yang dilakukan meliputi persiapan media tanam, pembibitan, penyiraman, pemupukan, pengendalian hama penyakit, panen, dan pascapanen. Hasil pengamatan pada tanaman Peperomia obtusifolia, Neoregelia schultesiana, dan Begonia ‘orococo’ yang menggunakan metode perbanyakan setek batang tergolong cepat sehingga selama periode magang tanaman tersebut memenuhi kriteria perusahaan, sedangkan Peperomia caperata dan Peperomia argyreia yang diperbanyak dengan menggunakan metode setek daun memiliki pertumbuhan yang lambat sehingga selama periode magang tanaman tidak memenuhi kriteria panen perusahaan. Hydrangea macrophylla memiliki umur panen rata-rata sekitar 15 MST sehingga periode pengamatan selama 8 minggu tidak dapat mengamati tanaman sampai panen. Hasil analisis usahatani dengan asumsi luasan 200 m2 beserta greenhouse lengkap dan manajemen yang sudah ada pada Peperomia obtusifolia, Peperomia argyreia, Peperomia caperata, Begonia ‘orococo’, dan Neoregelia schultesiana menghasilkan pendapatan yang lebih tinggi dari pengeluaran., The internship activities was carried out in March – July 2021 at PT. Melrimba Mitra, Bogor, West Java. The aims of the internship is to increase experience, knowledge, and skills in production management in ornamental plants, particularly of peperomia, bromelia, begonia as ornamental pot plant and hortensia as ornamental landscape plant. The technical activities in production management including production schedule from planting preparation until they are ready to harvest and fulfil the harvest criteria. Growth measurement on Peperomia obtusifolia, Neoregelia schultesiana, and Hydrangea macrophylla included number of leaves and plant height. Growth measurement on Peperomia caperata and Peperomia argyreia included number of shoots. Growth measurement on Begonia ‘orococo’ included the length of leaf, width of leave, and number of leaves. Cultivation activities include preparation of planting media, nurseries, watering, fertilizing, controlling pests and diseases, harvest, and post-harvest. The results of observation on Peperomia obtusifolia, Neoregelia schultesiana, and Begonia ‘orococo’ using stem cuttings propagation method which is relatively fast so that during internship period the plants met the company’s harvest criteria, while Peperomia caperata and Peperomia argyreia propagated using the leaf cuttings method had slow growth. So that during the internship period the plants did not meet the company’s harvest criteria. Hydrangea macrophylla has an average harvest age of about 15 WAP so that the observation period of 8 weeks cannot observe the plant until harvest period. The result of farming analysis using 200 m2 assumption area with complete greenhouse and existed management of Peperomia obtusifolia, Peperomia argyreia, Peperomia caperata, Begonia ‘ orococo’, and Neoregelia schultesiana produce more income than the output.
Keyword: harvest criteria, leaf cuttings, ornamental landscape plant, ornamental pot plant, stem cuttings

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.
Keyword: