Judul: Pengaruh Waktu Tebang terhadap Keawetan Alami Bambu Andong (Gigantochloa psedoarundinace)
Abstrak: Gigantochloa pseduarundinaceae, also known as Andong bamboo, used in this study. Samples were taken from bamboos which were harvested once each month in a year starting from February 2013 to January 2014. Bamboos culms were cut into strips. The strips were put in a safe, dry place, and free from wood destroying organisms. After all of the bamboos were collected, the laboratory testing is conducted based on SNI 01.7207-2006 methods. Field testing were also conducted based on ASTM D 1758-06 methods. According to the laboratory test, the bamboos were categorized as durability class III (medium durability) and durability class IV (bad durability). According to laboratory testing, the least loss of bamboo mass occurred on Maret and the highest number of termite mortality occurred on November. While, the results of the field test show that the value of the highest durability grade and the weight lowest loss rate was occurred on bamboo which is harvested in March to May. Best subset regression were used to determine the environmental factors during harvesting process which was dominantly affecting the bamboos' durability. The observed environmental factors were rain levels, humidity, and temperature. According to best subset regression analysis, the rain level and humidity during the harvesting period were two main factors affecting the bamboos' natural durability. The best subset regression resulted that rainfall and humidity during the harvest were the two main factors that affect the durability of bamboo at observed daily rainfall intervals (1-20 mm). Rain levels and humidity give fluctuating effects on the loss of mass. The maximum loss was happened on 74% humidity. If the humidity is bellow 74%, or above 74%, the mass loss tend to decrease. The rain level also affect the mass loss. Low rainfall level 1 to 4 mm showed the decrease in mass loss, and became stabilized when the rain level reach above 4 mm. According to the data, it is recommended to harvest the bamboos on March to Mei, when the durability are the highest and the mass loss are the lowest.
Keyword: Bogor Agricultural University (IPB), resistance class, natural durabiliy, mass loss, harvesting time, environmental factors

Judul: Pengaruh Waktu Tebang Terhadap Kekuatan Lentur Bambu Andong (Gigantochloa Pseudoarundinaceae (Steudel) Widjaja).
Abstrak: Pemanenan atau penebangan bambu andong secara tradisional dilakukan pada waktu–waktu tertentu, yaitu umumnya pada awal musim kemarau. Faktor–faktor lingkungan antara lain suhu, kelembaban, curah hujan, dan intensitas cahaya berpengaruh penting pada metabolisme bambu sehingga mempengaruhi kekuatan lentur bambu. Penelitian ini bertujuan untuk mengetahui pengaruh waktu tebang terhadap kekuatan lentur bambu andong serta menentukan faktor lingkungan yang paling berpengaruh terhadap kekuatan lentur bambu andong. Pada penelitian ini, pemanenan dilakukan selama satu tahun, yaitu satu batang bambu ditebang setiap akhir bulan yang dimulai Februari 2013 sampai Januari 2014. Bambu yang diambil setiap bulan dibuat contoh uji sesuai standar ASTM D 143-94 untuk diuji kekuatan lenturnya. Hasil penelitian menunjukkan bahwa MOE dan MOR tertinggi diperoleh pada bambu yang dipanen bulan Maret. Berkaitan dengan hal tersebut, jika diinginkan kekuatan tertinggi disarankan untuk memanen bambu andong pada bulan Maret. Kekuatan alami bambu terutama dipengaruhi intensitas cahaya, suhu, dan kelembaban, sedangkan curah hujan tidak berpengaruh nyata.
Keyword: bambu andong, kekuatan lentur, waktu tebang

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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