Judul: Karakteristik Cross Laminated Timber dari Kayu Sengon (Falcataria moluccana (Miq.) Barneby & J.W. Grimes) dan Mindi (Melia azedarach L) menggunakan Perekat Isosianat
Abstrak: Wood needs as raw material construction has been increased. The advance of wood engineering technology can develop product by the raw material from the fast growing species. CLT (Cross Laminated Timber) is wood engineered product manufactured by lumber panel layer was placed perpendicular to raise a rigidity and stability. The aim of this research is to determined wood influence to characteristic of mechanical and physical properties of CLT products of fast growing species especially mindi (Melia azedarach L) and sengon (Falcataria moluccana (Miq.) Barneby & J.W. Grimes). This research was conducted by the manufacturing of panel CLT and testing of physical properties (density, moisture contents, swelling, hot water delamination, and cold water delamination) and mechanical properties (bonding, racking stiffness, and racking strength). The results showed CLT-450 mindi panel was relative more forceful than CLT-450 sengon panel. Physical properties testing carried out density, moisture content, soaking cold water delamination, and hot water delamination of CLT-450 mindi panel is higher than the CLT-450 sengon panel. Shrinkage CLT-450 mindi panel lower than CLT-450 sengon panel, but swelling volume (CLT mindi) higher than CLT-450 sengon panel. The applications of isocyanate relative more resistant to soaking cold water delamination than soaking hot water delamination. Beside of the influence of density, the bonding strength value of CLT-450 mindi panel higher than CLT-450 sengon panel which was contribute to racking strength test. However, the influence of water content to stiffness of CLT-450 sengon panel inverse to higher than CLT- 450 mindi panels. TR 1 correction and TR 5 carried out CLT-450 sengon and mindi panel had greatest point on water displacement.
Keyword: Bogor Agricultural University (IPB), racking strength, racking stiffness, mindi, sengon, CLT

Judul: Karakteristik cross laminated timber kayu kecapi (Sandoricum koetjape Merr) berdasarkan orientasi sudut lamina
Abstrak: Cross Laminated Timber (CLT) is a multi-layer wooden panel made from lumber. Each layer of boards are placed cross-wise to the adjacent layers for increased rigidity and stability. The objectives of this research is used to determine the magnitude of the influence of orientation angle of the lamina of the mechanical and physical properties of cross laminated timber panels from kecapi wood (Sandoricum koetjape Merr) by using isosianat adhesive. The CLT panel was made from kecapi wood with 15 cm in thickness (five layers) from the board with 3 cm x 18 cm x 150 cm in size and orientation angle 450 and 900. The adhesive was used isosianat with surface weight 280 g/m³. Testing of the physical properties of CLT consist of moisture content, density, shrink/swelling and delamination test. Otherwise testing of mechanical properties of CLT include bonding strength and racking test. Result of racking test show that CLT’s stiffness at 450 angle larger than 900 angle; likewise, the strength of CLT show that at 450 angle stronger than 900 angle.
Keyword: Bogor Agricultural University (IPB), angle orientation., isosianat, kecapi wood, cross laminated timber

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