Judul: Physical and Mechanical Properties and Durability of Impregnated Fast-Growing Wood by Nano Silica from Bamboo Betung Sticks
Abstrak: Sengon (Paraserianthes falcataria L. Nielsen.) dan Jabon (Anthocephalus cadamba Miq.) merupakan jenis pohon cepat tumbuh yang memiliki kualitas kayu yang rendah dalam hal kekuatan, keawetan, kerapatan, stabilitas dimensi serta memiliki porsi kayu juvenile yang tinggi. Tujuan penelitian, menganalisis pengaruh perlakuan impregnasi MEG (Monoethylene Glycol) dan nano silika batang bambu terhadap sifat fisis, sifat mekanis dan keawetan kayu cepat tumbuh. Larutan impregnan yang digunakan terdiri dari kontrol (tanpa perlakuan), MEG, MEGSilika 0,5%, MEGSilika 0,75% dan MEGSilika 1%. Proses impregnasi dimulai dengan pemberian vakum 0,5 bar selama 60 menit dan dilanjutkan dengan pemberian tekanan 2,5 bar selama 120 menit. Hasil penelitian menunjukan bahwa perlakuan impregnasi MEG dan nano silika mampu meningkatkan kerapatan, Modulus of Elasticity (MOE), Modulus of Rupture (MOR), kekerasan, perubahan warna (ΔΕ), dan mortalitas rayap kayu kering kayu cepat tumbuh. Perlakuan MEG dan nano silika juga mampu menurunkan persentase kehilangan berat pada pengujian rayap kayu kering dan uji kubur kayu sengon serta kayu jabon. Hasil pengujian berbanding lurus dengan nilai weight percent gain (WPG). Perlakuan MEGSilika 1% menunjukan nilai yang paling optimum untuk kayu sengon dan kayu jabon., Sengon (Paraserianthes falcataria L. Nielsen.) and Jabon (Anthocephalus cadamba Miq.) are fast growing tree species that have low wood qualities in terms of strength, durability, specific gravity, dimensional stability and high portion of juvenile wood. The purpose of this study was to analyze MEG (Monoethylene Glycol) and nano silica of bamboo betung sticks impregnation treatments on physical and mechanical properties and durability of fast-growing wood. The solutions were consisted of control (water treated), MEG, MEGSilica 0.5%, MEGSilica 0.75% and MEGSilica 1%. The impregnation process was initiated by applying a vacuum of 0.5 bar for 60 minutes and continued by 2,5 bar pressure for 120 minutes. The results showed that MEG and nano silica impregnation increased the specific gravity, Modulus of Elasticity, Modulus of Rupture, hardness, color change (ΔΕ), and drywood termite mortality of treated fast growing wood. MEG and nano silica treatments also reduced weight loss percentage in the dry wood termite test and graveyard test of treated sengon and jabon wood. The test results are directly proportional to the weight percent gain (WPG) value. MEGSilica 1% treatment was the most optimal treatment for sengon wood and jabon wood.
Keyword: batang bambu betung, impregnasi, jabon, nano silika, sengon, bamboo betung sticks, impregnation, nano silica

Judul: Physical, Mechanical Properties and Durability of Impregnated Sengon Wood by Nano Silica orignated from Betung Bamboo Leaves
Abstrak: Sengon (Falcataria moluccana Miq.) merupakan jenis kayu cepat tumbuh yang memiliki beberapa kelemahan, yaitu berat jenis, kekuatan, keawetan, kerapatan dan stabilitas dimensi yang rendah. Penelitian ini bertujuan untuk menganalisis pengaruh perlakuan impregnasi menggunakan monoethylene glycol (MEG) dan nano silika daun bambu betung terhadap sifat fisis, mekanis dan keawetan kayu sengon. Salah satu metode modifikasi kayu adalah impregnasi. Proses impregnasi memiliki keunggulan yaitu dapat meningkatan kerapatan dan kekerasan kayu dengan memasukkan polimer ke dalam struktur kayu. Larutan impregnasi yang digunakan yaitu kontrol (tanpa perlakuan), MEG, MEGSilika 0.5% dan MEGSilika 1%. Proses impregnasi dimulai dengan pemberian vakum 0.5 bar selama 60 menit dan dilanjutkan dengan pemberian tekanan 2.5 bar selama 120 menit. Hasil penelitian menunjukkan perlakuan impregnasi MEG dan nano silika berpengaruh nyata dan meningkatkan nilai weight percent gain (WPG), kerapatan, perubahan warna (ΔΕ), MOE, MOR, kekerasan dan persentase mortalitas rayap tanah Coptotermes curvignathus serta menurunkan persentase kehilangan berat pada kayu sengon. Secara keseluruhan perlakuan MEGSilika 1% merupakan perlakuan yang paling optimum untuk kayu sengon yang berumur 5 tahun, Sengon (Falcataria moluccana Miq.) is fast growing wood species which has inferior characteristics i.e. low specific gravity, strength, durability, density and dimensional stability. The objective of this study was to analysis the effect of monoethylene glycol (MEG) and nano silica originated from betung bamboo leaves impregnation treatment on physical, mechanical properties and durability of sengon wood. One of wood modification methods is impregnation. Impregnation process could increase the wood density and hardness by introducing polymer into wood structure. The impregnation solution were consisted of water treated (untreated), MEG, MEGSilika 0.5% and MEGSilika 1%. The impregnation process was initiated by applying 0.5 bar of vacuum for 60 min and followed by 2.5 bar of pressure for 120 min. The results showed that MEG and nano silica impregnation treatment had significant effect on and increased weight percent gain (WPG), density, color changes (ΔΕ), MOE, MOR, hardness and mortality percentage of termite Coptotermes curvignathus and decreased weight loss percentage. MEGSilika 1% was the optimum treatment for of 5-year-old sengon wood.
Keyword: daun bambu betung, impregnasi, keawetan, nano silika, sengon, betung bamboo leaves, durability, impregnation, nano silica

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model