Judul: penjakit  mati budjang dari tjengkeh
Abstrak: Already in 1936 AL advocated the extension of the culture of cloves in Indonesia by postulating the first theorem of his thesis: ''The importance of cloves in the industry of native cigarettes called" "kretek", is of such a nature that on account of this reason alone" "it would be remunerative to pay more attention to the culture of" "cloves in the Netherlands East India than has been the case up till" Previously, the Commissioner of State had mentioned in the National Assembly during a crisis-debate on February 10, 1932, that in trying out new sources of prosperity the culture of cloves might prove to be promising.
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Judul: Observation of dieback disease of  clove in Semarang and Tegal  regencies, Central Java
Abstrak: Cengkih (Syzygium aromaticum L. Merr. & Perry) merupakan tanaman rempah asli Indonesia yang memegang peranan penting dalam pembangunan perkebunan untuk peningkatan devisa negara. Di Indonesia, bunga cengkih kering digunakan terutama untuk bahan baku campuran rokok kretek dan sebagian kecil untuk keperluan industri makanan, minuman, kosmetik dan farmasi. Serangan hama dan penyakit menyebabkan terhambatnya pertumbuhan tanaman cengkih bahkan kematian pada tanaman. Hal ini dapat menurunkan kualitas dan kuantitas produktivitas cengkih. Salah satu penyakit yang menyerang tanaman cengkih dan paling merusak tanaman cengkih yaitu penyakit mati pucuk yang disebabkan oleh Bakteri Pembuluh Kayu Cengkih (BPKC). Penelitian ini dilakukan untuk mengamati kondisi serangan penyakit mati pucuk di lapangan dan mengetahui pengaruh praktek-praktek budidaya serta kemungkinan penyebab penyakit mati pucuk. Pengamatan dilakukan di dua kabupaten yaitu Kabupaten Semarang dan Tegal, Provinsi Jawa Tengah. Pengamatan dilakukan pada pertanaman cengkih yang berada di daerah perbukitan dan daerah sekitar pemukiman, kemudian dihitung kejadian dan keparahan gejala penyakit mati pucuk, serta mengamati keberadaan penggerek dan kanker batang. Sampel gejala penyakit mati pucuk diambil dan diamati di laboratorium untuk melihat keberadaan bakterinya. Kejadian serangan penyakit mati pucuk di Kabupaten Tegal lebih tinggi dibandingkan Kabupaten Semarang sedangkan keparahan serangan penyakit mati pucuk di Kabupaten Semarang lebih tinggi dibanding Kabupaten Tegal. Penyakit BPKC tidak hanya disebabkan oleh bakteri saja tetapi ada peran OPT lain yaitu penggerek dan kanker batang, Cloves (Syzygium aromaticum L. Merr. & Perry) is an Indonesia origin spices, has important role in the development of plantations to increase state revenues. In Indonesia, dried cloves used primarily as raw material mixture of cigarettes and a small portion for the purposes of the food industry, cosmetic and pharmaceutical. Pests and diseases causes inhibition of cloves growth and death. It can decrease the quality and quantity of cloves productivity. One of the diseases which can infect cloves is called dieback caused by Wooden Vessels Bacteria Cloves (in indonesian is BPKC). The purpose of this study were to observe the dieback disease condition in the field, and determine the influence of cultivation practices on the diseases. Observations were ca rried out in districts of Semarang and districts of Tegal in Central Java Province. Observations were made on the plantation in hilly areas and residential areas, and then were be calculated the incidence and severity of dieback symptoms. The existence of stem canker and stem borer symptoms were also observed which might be accompanied to dieback disease. Symptoms of dieback samples were detection of bacteria in the laboratory. Dieback incidence in district of Tegal is higher than the district of Semarang while dieback severity in district of Semarang is higher than the district of Tegal. Bosed on field observation and laboratory detection, the dieback symptoms on clove in those areas were not only caused by bacteria, but stem canker and stem borer were also have a role on the development of the symptoms
Keyword: cengkih, kanker, penyakit mati pucuk, serangga

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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