Judul: Eco-Friendly Particle Board from Coco Fiber with Starch-Based Adhesives
Abstrak: Serat sabut kelapa merupakan serat alami yang memiliki potensi untuk dimanfaatkan sebagai bahan baku pembuatan papan partikel, karena mengandung lignoselulosa dan memiliki sifat ramah lingkungan. Penggunaan perekat maltodekstrin dengan asam sitrat sebagai perekat ramah lingkungan cukup baik dalam mengikat serat kayu sehingga pada penelitian ini mencoba menggunakan maltodekstrin-asam sitrat. Penelitian ini bertujuan untuk mengetahui ukuran partikel yang optimum untuk menghasilkan produk papan partikel. Penelitian ini menggunakan ukuran partikel sebesar 40-50 mesh, 50-60 mesh, dan lolos 60 mesh. Sifat fisis yang diuji dalam penelitian ini antara lain kerapatan, kadar air, daya serap air dan pengembangan tebal. Sifat mekanis yang diuji yaitu Modulus of Elasticity (MOE) dan Modulus of Rupture (MOR). Hasil penelitian menunjukkan ukuran partikel ukuran partikel tidak memberikan pengaruh yang nyata pada kerapatan, kadar air, daya serap air, pengembangan tebal, MOE dan MOR. Nilai sifat fisis yang diuji telah mencapai standar JIS A 5908-2003. Ukuran partikel optimum seratsabut kelapa untuk menghasilkan papan partikel cukup baik yaitu lolos 60 mesh., Coconut fiber is a natural fiber that has the potential to be used as a raw material for making particleboard, because it contains lignocellulose and has environmentally friendly properties. The use of maltodextrin adhesive with citric acid as an environmentally friendly adhesive is quite good in binding woodfibers, so in this study we tried to use maltodextrin-citric acid. This study aims to determine the optimum particle size to produce particleboard products. This study used a particle size of 40-50 mesh, 50-60 mesh, and passed 60 mesh. The physical properties tested in this study include density, moisture content, water absorption and thickness expansion. The mechanical properties tested were the Modulus of Elasticity and the Modulus of Rupture. The results showed that the particle size didn’t have a significant effect on density, moisture content, water absorption, thickness swelling, MOE and MOR. The value of the tested physical properties has reached the JIS A 5908-2003 standard.The optimum particle size of coco fiber to produce particleboard is quite good, which is passed 60 mesh.
Keyword: Coco fiber, Mechanical properties, Particle board, Particle size, Physical properties

Judul: Sifat Akustik dan Mekanik Papan Partikel Kelobot Jagung dan Bambu Sembilang Berperekat Kitosan Larut Air
Abstrak: Papan partikel menjadi solusi yang ideal untuk mengganti material kayu. Papan partikel dapat dibuat dari serat alami atau bahan berlignoselulosa lainnya. Kelobot jagung dan bambu sembilang dapat menjadi bahan komposit yang ramah lingkungan. Penelitian ini bertujuan untuk menyintesis dan menganalisis sifat fisik, mekanik, dan akustik papan partikel kelobot jagung dan bambu sembilang. Variasi ukuran partikel sebesar 4 mesh dan 4-14 mesh. Komposisi campuran kelobot jagung dan bambu sembilang adalah 100: 0; 25:75; 50:50; 75: 25; dan 0:100. Jenis perekat yang digunakan adalah perekat alami kitosan larut air dengan kadar perekat 8%. Target kerapatan papan partikel yang diproduksi adalah 0,8 g/〖cm〗^3. Hasil penelitian menunjukkan papan terbaik dengan nilai terdapat pada papan dengan komposisi 75% kelobot jagung dan 25% bambu sembilang ukuran 4 mesh. Uji akustik menunjukkan papan partikel dengan komposisi 100% jagung (4 mesh) menghasilkan nilai koefisien absorpsi suara tertinggi sebesar 0,093 pada frekuensi 3000 Hz., Particleboard is an ideal solution to substitute wood materials. Particleboard can be made from natural fibers or other lignocellulosic materials. Corn husks and sembilang bamboo can be composite materials that are eco friendly. This study aims synthesis and analyze the physical, mechanical, and acoustical properties of corn husk and sembilang bamboo particleboard with variations in particle size and composition. The variation of particle size is 4 mesh and 4-14 mesh. Composition of particle mixtures between corn husk and sembilang bamboo were used in (%) is 100: 0; 25:75; 50:50; 75:25; and 0:100. The type of natural adhesive used is water-soluble chitosan with an adhesive content of 8%. The targeted density of the particleboard is 0,8 g/〖cm〗^3. The results show the best particleboard was found in a composition of 75% corn husks and 25% sembilang bamboo (4 mesh). Acoustic testing shows that the highest sound absorption coefficient was given by particleboard with composition of 100% cornhusk (4 mesh) at frequency 3000 Hz.
Keyword: Corn husk, particleboard, sembilang bamboo, water soluble chitosan

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