Judul: Daya Tahan Lapisan Finishing Interior Pelarut Air pada Kayu Jati, Kamper, dan Pinus.
Abstrak: The limited supply of wood from natural forests makes markets interest to wood from plantation forest increase. However, the wood comes from plantation forests considered to be low in quality, including durability. Finishing is one of the solutions to overcome these problems. In this present day there has been developing water based finishing materials (waterbased finishes) that is safe for the environment and does not contain harmful chemicals that can threaten human health. A study has been conducted to determine the durability of the water based finishing layer (Impra Aqua and Sayerlack Waterborne) on Teak (Tectona grandis), Camphor (Dryobalanops aromatica), and Pine (Pinus merkusii). The type of testing conducted covers on the hot and cold test, resistance to household chemical materials, and cross-cut test. The test results showed that the finishing layer is resistant to the hot and cold test, thus can be classified into class 10 (with a completely unblemished surface). The Layer formed by Impra Aqua finishing material is also resistant to all household chemicals tested, so it is classified into class 10. Meanwhile the layer resistance of Sayerlack Waterborne finishing against ballpoint ink tend to be less powerful, so it is classified into class 9, but the finishing materials is resistant to chemicals such as Povidone-iodine. In the test results of paint adhesion (cross cut test), teak wood in wet conditions coated with both types of finishing materials has the weakest adhesion strength, so it is classified into class 3B. Meanwhile, finishing layer for all the wood samples under dry conditions have very strong adhesion, so it is classified in class 5B.
Keyword: Bogor Agricultural University (IPB), Sayerlack Waterborne, Impra Aqua, Hot and cold test, Cross cut test, Finishing, Waterbased

Judul: Pengaruh Cuaca terhadap Daya Tahan Lapisan Finishing Eksterior Berpelarut Air pada Kayu Kamper, Jati, dan Pinus
Abstrak: Penggunaan kayu sebagai bahan kontruksi belum dapat tergantikan oleh bahan lain. Pengaruh lingkungan, biologis, dan non-biologis dapat menyebabkan kayu terdegradasi. Finishing merupakan solusi untuk mengatasi masalah tersebut. Tujuan penelitian ini adalah (1) menentukan daya tahan lapisan finishing eksterior berpelarut air Ultran Aqua Politur (UAP) dan Sayerlack terhadap pengaruh cuaca terbuka pada kayu kamper, jati, dan pinus berpenampang radial dan tangensial pada kondisi basah (KA 25-30 %) dan kering (KA 10-15 %) serta (2) isolasi dan identifikasi cendawan yang tumbuh pada contoh uji. Contoh uji dibuat dengan ukuran 20 cm x 10 cm x 2 cm yang kemudian diampelas dan dilaburi bahan finishing eksterior berpelarut air UAP dan Sayerlack. Setelah itu, contoh uji dipaparkan selama 36 bulan di ruang terbuka dan diamati perubahannya berdasarkan tingkat kerusakan terhadap cacat checking, cacat cracking, dan cacat serangan mikroba. Hasil penelitian menunjukkan bahwa lapisan finishing eksterior dengan pelarut air pada kayu kamper, jati, dan pinus yang dipaparkan selama 36 bulan menunjukkan penurunan rating yang berarti. Lapisan finishing UAP memberikan daya tahan yang lebih baik dibandingkan daya tahan lapisan finishing Sayerlack. Aplikasi finishing UAP pada kayu jati penampang radial dengan kondisi kering memberikan daya tahan yang paling baik. Cendawan yang ditumbuh pada contoh uji ada tujuh yaitu Dacriophinac sphatularia, Trichoderma sp.; Irpex lacteus, Bispora sp.; Mycellia sterilia, Drechslera sp.; dan Pycnoporus sp..
Keyword: checking, cracking, eksterior, lapisan finishing, serangan mikroba

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