Judul: Karakteristik permukaan finir kupas beberapa kultivar Poplar
Abstrak: Fenomena pemanfaatan kayu cepat tumbuh sudah terjadi secara global. Kayu cepat tumbuh memiliki potensi besar dalam pembuatan finir untuk kayu lapis dan LVL. Perancis merupakan produsen kayu Poplar terbesar di Eropa. Penelitian ini menganalisa tentang lima kultivar terbaik yang digunakan untuk struktural. Tujuan dari penelitian ini adalah menganalisis karakteristik permukaan beberapa kultivar Poplar berdasarkan kekasaran permukaan, retak kupas, dan keterbasahan. Kekasaran permukaan diukur menggunakan surface roughness tester. Metode pengukuran retak kupas menggunakan tinta dan diukur dibawah digital video microscope. Pengujian keterbasahan diukur berdasarkan pengukuran sudut kontak antara cairan dan permukaan kayu. Hasil penelitian ini menunjukkan bahwa kekasaran permukaan dan retak kupas mengalami penurunan dari empulur ke kulit. Finir dekat empulur memiliki sudut kontak yang lebih kecil daripada finir dekat kulit. Kekasaran permukaan dan retak kupas memiliki pengaruh yang nyata terhadap keterbasahan.
Keyword: contact angle, cultivar, lathe check, surface roughness, wettability

Judul: Analisis Gaya Pemotongan dan Kualitas Permukaan Vinir Kayu Poplar (Populus spp.)
Abstrak: Fourteen new Poplar (Populus spp.) cultivars were studied in order to create the referential of Poplar quality. This report presents the results of their ability to peeling and an analysis of the quality of its products, veneers. The logs were peeling into veneers. Peeling process was differentiated by radial position, sapwood and false heartwood. Analyses of variances were used to interpret the data obtained by moisture content, percentage of fuzzy grain, the number of wave veneer, radius of wave veneer, area of wave veneer, and the cutting force consisting of Xc (vertical knife), Yc (horizontal knife), Xb (vertical bar), and Yb (horizontal bar). All of Poplar cultivar have a low specific gravity (0.30-0.38) so they were easy to peeling and have a low cutting effort. It also has sufficient moisture content. Among those cultivars, the Dvina shows a poor ability to peeling and surface quality of veneer. The radial position is significantly affected to moisture content, cutting forces, and fuzzy grain. But the values between two radial positions were not significantly different since the anatomical of Poplar was less heterogen.
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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