Judul: Seed Coating Formula Made from Plant-based Fungicide to Maintain The Quality of Cocoa Seeds (Theobroma cacao L.)
Abstrak: Kakao merupakan salah satu komoditas perkebunan terbesar di Indonesia yang berkontribusi sebagai sumber pendapatan devisa negara, dan komoditas yang sangat penting didalam perdagangan dunia. Namun, karena benih kakao masih sering terserang hama dan jamur dan memiliki umur simpan singkat, benih kakao memerlukan penanganan yang tepat. Seed Coating adalah salah satu cara untuk melindungi benih melalui proses pelapisan benih dengan zat tertentu yang dapat mencegah mikroba kontaminan pada benih kakao. Tujuan penelitian ini adalah menganalisis pengaruh penggunaan seed coating dengan kombinasi beberapa bahan fungisida nabati terhadap mutu benih kakao. Prosedur penelitian meliputi persiapan sampel, pembuatan larutan seed coating, pengaplikasian seed coating, pengamatan selama 14 hari masa simpan pada suhu ruang dan 14 hari pada masa semai. Larutan seed coating dibuat dari pektin dengan tambahan kombinasi minyak serai wangi 3% dan 5%, minyak cengkeh 3% dan 5%, minyak pala 3% dan 5% dan pengemulsi. Pengaplikasian seed coating dilakukan menggunakan metode pencelupan sebanyak satu kali selama lima menit. Seed coating perlakuan P2 merupakan perlakuan paling efektif yang mampu meminimalisir kontaminan sebesar 14,4%, kadar air 40,76%, benih yang berkecambah pada penyimpanan 3,73%, dan benih busuk pada penyimpanan 4,24%, serta daya kecambah 77,66%., Cocoa is one of the largest plantation commodities in Indonesia which contributes as a source of foreign exchange earnings for the country, and a very important commodity in world trade. However, because cocoa seeds are often attacked by pests and fungi and have a short shelf life, cocoa seeds require proper handling. Seed Coating is one way to protect seeds through the process of coating seeds with certain substances that can prevent microbial contaminants on cocoa seeds. The purpose of this study is to analyze the effect of use seed coating with a combination of several plant-based fungicide ingredients against the quality of cocoa seeds. The research procedure includes sample preparation, seed coating solution preparation, application of seed coating, observation for 14 days of storage time at room temperature and 14 days at seedling time. Seed coating solution made from a combination of citronella oil 3% and 5%, clove oil 3% and 5%, nutmeg oil 3% and 5% with pectin and emulsifier. Application of seed coating performed using the immersion method once for five minutes. Seed coating P2 is the most effective treatment which is able to minimize contaminants by 14.4%, moisture content 40.76%, seeds that germinated at storage 3.73%, rotted seeds at storage 4.24%, and germination rate of 77.66%.
Keyword: benih kakao, kontaminan, minyak atsiri, pektin, seed coating

Judul: Improving quality of cacao (theobroma cacao l.) Seeds and seedlings through physiological and biological approaches
Abstrak: Revitalisasi program pengembangan tanaman kakao pada tahun 2009/2010 membutuhkan 168.000.000 benih. Keberhasilan program ini tergantung pada ketersediaan benih yang berkualitas, khususnya benih yang vigor dan sehat. Benih bervigor tinggi diperoleh dari pohon induk yang vigor dan sehat serta dipanen pada saat masak fisiologis. Distribusi benih bervigor rendah dan terinfeksi penyakit (seedborne diseases) mengakibatkan kerugian yang sangat besar dan berjangka panjang dalam mengurangi produktivitas tanaman kakao. Permasalahan utama benih kakao yaitu bersifat rekalsitran; berkadar air tinggi, mudah terinfeksi patogen, dan memiliki periode konservasi yang relatif lebih singkat, sehingga penurunan mutu fisiologis benih dapat terjadi lebih cepat. Oleh karena itu perlu dilakukan teknik invigorasi yang tepat dengan perlakuan matriconditioning plus Trichoderma spp. dan penggunaan medium campuran tanah, pasir, kompos (2:1:1) plus agens hayati. Kedua perlakuan ini merupakan strategi penting untuk memperbaiki dan meningkatkan mutu benih atau bibit kakao yang sehat serta ramah lingkungan.
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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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