Judul: Uji Klon dan Uji Kerapatan Kayu Jati Unggul Nusantara (JUN) Umur 45 Bulan di Kabupaten Purwakarta Jawa Barat
Abstrak: JUN (Jati Unggul Nusantara) diklaim memiliki sifat unggul cepat tumbuh. Informasi ilmiah tentang keragaan klon pada JUN belum banyak diekplorasi termasuk kualitas kayu yang masih belum banyak diketahui khususnya pada pertumbuhan awal. Oleh karena itu penelitian kaitannya dengan kedua hal tersebut perlu dilakukan khususnya untuk JUN umur 45 bulan. Tujuan dari penelitian ini adalah untuk mengkaji kinerja 41 klon JUN termasuk menduga parameter genetic dan pengaruh microsite terhadap keragaan klon JUN dan menduga kerapatan kayu pada klon JUN dengan pertumbuhan terbaik dan terburuk. Penelitian uji klon JUN dilakukan di plot penelitian Purwakarta (Jawa Barat) menggunakan rancangan acak lengkap (RCBD) yang dilakukan pada 41 klon JUN dan 1 lot kontrol jati lokal asal benih yang ditanam pada 2 microsite dengan pemberian pupuk dan jarak tanam yang berbeda. Pengujian dilakukan dengan mengukur morfologi pertumbuhan pohon, kemampuan penetrasi menggunakan nalat Pylodin, dan kerapatan kayu pada pohon. Hasil penelitian menunjukkan daya sintas di lapangan memiliki nilai rata-rata yang tinggi (>90%). Hasil penelitian menunjukkan nilai repeatability untuk diameter sebesar Rc 2 =0.62 dan untuk parameter tinggi yaitu Rc 2=0.70. Nilai korelasi genetik sebesar rG= 0.061 dan korelasi fenotipik rP=0.842. Microsite terbaik JUN umur 45 bulan adalah microsite 4 dengan jarak tanam 5 m x 2 m dan pupuk dasar 5 kg. Nilai estimasi perolehan genetik menunjukkan bahwa karakter tinggi dapat direkomendasikan sebagai karakter seleksi klon. Hasil penelitian juga melaporkan kerapatan kayu pada JUN umur 45 bulan belum stabil, sehingga belum bisa ditetapkan bahwa kecenderungan kerapatan kayu antara klon terbaik (superior) dan terburuk (inferior). Hal ini ditunjukkan oleh hubungan yang rendah antara kemampuan penetrasi dan kerapatan kayu pada kedua klon tersebut.
Keyword: JUN (Jati Unggul Nusantara), clone test, pilodyn penetration, wood density test

Judul: Uji Klon Jati Unggul Nusantara (JUN) Umur 30 Bulan Di Kabupaten Purwakarta, Jawa Barat
Abstrak: Jati Unggul Nusantara (JUN) is known as commercial planting stock material that is vegetatively propagated by means of shoot cutting technique. JUN is claimed to be fast growing. However, scientific information on the growth of selected JUN clones from clonal tests is still lacking. The objective of the study were i) to review performance of 41 JUN clones, ii) to estimate their genetic parameters and iii) to assess the effect of microsites on tested JUN clones. Genetic assessment of JUN clones was carried out in Purwakarta, West Java in a Randomized Complete Block Design (RCBD) consisting of 41 clones. The clones were planted on 4 microsites that were differentiated by fertilizer doses and spacings. The results showed that generally survival rates were high (>90%). In addition, repeatability at 30 months after planting was about = 0.948 (diameter) and = 0.699 (height), respectively. While genetic and phenotypic correlations between diameter and height were rG=0.315 and rP=0.864, respectively. The best microsite supporting growth of JUN clones at 30 months was found on microsite 1, namely spacing 3 m x 4 m with 3 kg organic fertilizer, while the best straight stem form (around 45% of the population) was observed on microsite 2.
Keyword: stemform, repeatability, genetic correlation, fenotipe correlation, Jati Unggul Nusantara (JUN)

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: