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 terhadap Rayap Tanah dan Jamur Pelapuk Kayu
Abstrak: Anthocephalus cadamba known as jabon in Indonesia is one of fast growing species. However, it has poor durability and classified into IV-V of durability class. It is necessary to apply wood preservation in terms of Improving the timber durability. The aim of this research is to examine the effectiveness of several methods in preserving wood using particular chemical preservatives from active boron against subterranean termites (Coptotermes curvignathus) and wood decay fungi (Schizophyllum commune). The preservatives consist of 5% concentrations of mixed Borax-Sodium Carbonax (BC) and Boric Acid Equivalent (BAE), cold bath, hot–cold bath and vacuum press were applied as the preservation methods. There were two responses observed in this research: the mortality of Subterranean Termites, and the timber weight loss resulting from the termites and the wood decay fungi attacks as well. The results show that the preservation of jabon timber using BC and BAE can improve its durability from C. curvignathus and S. commune attack. The durability from C. curvignathus attack increases from class V to class I while the durability from S. commune attack also improves from class V to class II.
Keyword: Sodium Carbonate., Schizophyllum commune, Coptotermes curvignathus, 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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