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: Characteristics of Impregnated Fast Growing Woods by Nano Silica Orignated from Betung Bamboo Leaves and  Monoethylen Glycol.
Abstrak: Sengon (Paraserianthes falcataria L. Nielsen.) dan Jabon (Anthocephalus cadamba Miq.) merupakan jenis pohon cepat tumbuh yang memiliki nilai kekuatan, keawetan, kerapatan, dan stabilitas dimensi yang rendah. Salah satu metode untuk meningkatkan nilai dari kayu cepat tumbuh yaitu dengan cara impregnasi. Proses impregnasi dimulai dengan pemberian vakum 0,5 bar selama 60 menit dan dilanjutkan dengan pemberian tekanan 2,5 bar selama 120 menit. Perlakuan MEG dan nano silika mampu meningkatkan nilai persentase weight percent gain, kerapatan, perubahan warna, modulus of elasticity, modulus of rupture, kekerasan, meningkatkan nilai mortalitas serta menurunkan persentase kehilangan berat pada pengujian rayap kayu kering, rayap tanah dan uji lapangan kayu sengon serta kayu jabon. Perlakuan MEG dan nano silika juga dapat meningkatkan kelas kuat kayu sengon yang semula berada pada kelas kuat III-IV menjadi kelas kuat III dan kelas kuat kayu jabon yang semula berada pada kelas kuat IV-V menjadi kelas kuat V. Kelas awet kayu sengon yang semula berada pada kelas awet V menjadi II dan untuk kayu jabon yang semula berada pada kelas awet V menjadi kelas awet II., Sengon (Paraserianthes falcataria L. Nielsen.) and Jabon (Anthocephalus cadamba Miq.) are fast-growing tree species that have low strength, durability, density, and dimensional stability values. One method to increase the value of fast growing wood is by impregnation. The impregnation process was started by applying a vacuum of 0,5 bar for 60 minutes and continued by applying a pressure of 2,5 bar for 120 minutes. In drywood termites, subterranean termites, and field tests of sengon wood and jabon wood, MEG and nano silica treatments were able to increase the values of weight percent gain, density, color change, modulus of elasticity, modulus of rupture, hardness, increase the mortality value, and reduce the percentage of weight loss in drywood termites and subterranean termites. MEG and nano silica treatment can also increase the strength class of sengon wood, which was originally in strong class III-IV to be strong class III, and the strong class of jabon wood, which was originally in strong class IV-V to be strong class V. Sengon wood, which was originally in durable classes V to II, and jabon wood, which was originally in durable classes V to durable class II.
Keyword: daun bambu betung, impregnasi, jabon, nano silika, sengon, bamboo betung leaves, 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