Judul: Pengawetan Kayu Jabon (Anthocephalus cadamba Roxb. Miq) dengan Bahan Pengawet Diffusol-CB
Abstrak: Jabon wood is a fast growing species that has a low mechanical physical properties and low durability. This study aims to determine the effect of Diffusol- CB on the durability of jabon wood in parts of pith to bark. The jabon trees in the age of 5, 6 and 7 years old and a parts of bottom, middle and top were used in this study. Other material is preservative Diffusol-CB with concentration of 5%. Preservation method used the cold bath for the period of 2 days (48 hours) and the durability test was conducted for 3 months in the field using procedure of American Society for Testing and Material (ASTM) D 1756 2008. The results showed that the value of retention in the average of 5.77 kg/m3 for wood samples near the bark and of 5.19 kg/m3 for the sample near the pith. The highest retention was 7.30 kg/m3 for the bottom part of jabon 6 years. Meanwhile jabon wood at the age of 7 years near the pith had the lowest retention 2.61 kg/m3. The experimental results also showed that the weight loss of untreated jabon wood was in the average of 52.71%. Maximum weight loss of 87.74% was found in the middle part of jabon wood near the bark at the age of 5 years. Meanwhile the lowest weight loss 14.77% retained by jabon wood at the bottom part near the bark for the age of 7 years. The jabon wood treated by diffusol CB 5% suffered weight loss in the average of 2.55%. This results give an indication that the Diffusol-CB with a concentration of 5% can increase the durability of jabon wood against termite attack. Degree of protection results showed that the degree of damage for untreated jabon wood was very large. Meanwhile the treated jabon wood didn’t show any damages on the samples.
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Judul: Pengaruh Metode Pengawetan Berbahan Aktif Boron pada Kayu Jabon (Anthocephalus cadamba Miq.) terhadap Serangan Rayap Kayu Kering dan Jamur Pelapuk Kayu
Abstrak: Jabon woods is one of the small scale community forest that had low durability and classified at IV-V of durability class, it is necessary for the preservation of the wood to increase the durability of timber value. The aim of this research is to know the effectiveness of some methods of preserving wood and preservative from active boron against dry wood termites and wood rot fungi.This research was using 5% concentrations of Borax mixed with Sodium Carbonate (BC) and Boric Acid Equivalent (BAE) as preservatives and using vacuum press, hot–cold bath, and cold bath as method of preserving. The observed object of this research are mortality of dry wood termites value, and weight loss of timber resulting from dry wood termites Cryptotermes cynocephalus and wood white rot fungi attack. The result showed in this research is the value of dry wood termite mortality and weight-timber values resulting from the attack dry wood termites C. cynocephalus and wood white rot fungi Pycnoporus sp. The results showed that the preservation of wood with preservatives Jabon BC and BAE can improve the durability of the dry wood termite attack C. cynocephalus of class IV to durability class I and II, while the wood rot fungi Pycnoporus sp. attack increased from durability class V be durability class II-III.
Keyword: Pycnoporus sp., Natrium Carbonate, Cryptotermes cynocephalus, boron, Anthocephalus cadamba

Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
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