Judul: Karakterisasi kulit buah jarak (Jatropa curcas L) dan pemanfaatannya sebagai bahan baku papan pertikel berkualitas
Abstrak: Jatropha fruit hulls (JFH) is a waste resulted from biodiesel process and its used only as compos materials. According to fiber proportion and chemical composition, JFH had a potency for using as raw materials of particleboard manufacturing. However, the acidity properties of JFH caused problem in UF resin curing, so that resulting inferior bonding strength of board. Adjusting of acidity and controlling of pressing temperature and time were expected to solve those problem. The objective of this research was to obtain the best condition to produce high quality particleboard made of JFH and UF resin. This research consist of five steps. The first step was to analyse of materials characteristic of JFH and UF resin included of pH, buffering capacity, chemical component, chemical compound, wettability, solid content, viscosity, and gelatine time. Suitability indicator between of JFH and UF was determined by extractive content, pH, and wettability. Second step was to analyse of particle immersing treatment (immersing in cold water for 24 hours, hot water for 1 hours, and 1% acetic acid solution) to physical and mechanical properties of particleboard. Third step was to analyse of pressing temperature and time to obtain optimum pressing condition in particleboard manufacturing. The fourth step was to analyse of wood shaving (mangium wood) and wood veneer (sengon and jabon wood) to reinforce of mechanical properties of particleboard. The last step was to analyse of non wood particle (bamboo and sorghum stalk) to reinforce of mechanical properties of particleboard. The result showed that JFH had alkali properties, it was caused by alkaline from several chemical compound that composed of JFH i.e ammonium bicarbonate, mercaptomethane, guaiacol, 2,6-dimethoxyphenol dan cyclopropyl carbinol. Immersing treatment was reducing of extractive content, pH and increased of JFH wettability. Furthermore, those parameter used as indicator to determine of lignocellulosic materials compatibility with UF resin to result the best quality of particleboard. Based on technical and efficiency considering, immering treatment in cold water for 24 hours, hot water for 1 hour, and 1% acetic acid solution were selected for particleboard manufacturing. The best properties of particleboard was resulted by JFH immersing treatment in acetic acid solution. The exploration of pressing temperature and time to obtain of the best pressing condition was expected for optimizing of UF resin polymerization. Hot pressing in 130 0C temperature for 10 minute resulting the best properties of particleboard, but the thickness swelling and modulus of elasticity value were not fulfill of JIS A 5908 (2003). The reinforcement method by strong materials were expected of resulting the improvement of mechanical properties. JFH and wood shaving mixture, overlaid with wood veneer, JFH and non wood particle mixture resulted to improve of physical and mechanical properties especially of MOE and MOR value. The overlaid with sengon and jabon veneer, and JFH and bamboo acid treated mixture was increasing of MOE and MOR value. The overlay technique by veneer and JFH and bamboo acid treated mixture resulting MOE value that fulfill of JIS A 5908 (2003). Based on this reseach had resulted of recomendations included of immersing in 1% acetic acid solution, hot pressing at
Keyword: Extractive, particle acidity, jatropha fruit hulls, particleboard, urea formaldehyde resin

Judul: Karakteristik Papan Partikel Tanpa Perekat dari Serat Sabut Kelapa dengan Perlakuan Oksidasi, Penambahan Parafin dan Waktu Kempa
Abstrak: Manufacture of binderless particleboard from coconut fiber research was done as an effort to use alternatives raw materials in timber industry which has become limited and to reduce adhesives synthetic that has pollute the environment such as urea formaldehyde (UF). Paraffin was expected to make the physical properties of particleboard better. The purpose of this research was to know the characteristics of binderless particleboard from coconut fiber based on particleboard standard JIS A 5908:2003 and determine the influence of oxidation treatment, additional paraffin and time of pressing on the characteristics of particleboard. Oxidation method was done by spraying hydrogen peroxide (15%) and ferrosulfate (7.5%), 10 minutes of pressing and 20 minutes at temperature 180 ºC with a pressure of 25 kgf/cm2. The results: density (0.44-0.56 g/cm3), moisture content (5.94-10.08%), all treatment met the standards. The results of strong hold spanner (19-80 kgf): only combination of oxidation treatment that met the standards. The result of thickness swelling: only combination of oxidation treatment, paraffin 0.5% and without paraffin with 20 minutes of pressing (8% and 12%) met the standards. In conclusion for all the treatment, the one that didn’t meet JIS standard: Internal Bond (IB), Modulus of Elasticity (MOE) and Modulus of Rupture (MOR).
Keyword: pressing time, particleboard, paraffin, oxidation, JIS A5908:2003, coconut fiber

Judul: Pengaruh vaksinasi terhadap dinamika populasi pada model SIR (Susceptible-Infected-Recovered)
Abstrak: SIR model can be used to model the spread of diseases in a closed population based on certain assumptions. In this research, the SIR model is formulated by including the factor of vaccination. As the result, the model has been shown to have two equilibrium points, i.e. disease free and endemic equilibrium. A simulation study is carried out to illustrate the model. The results show that some equilibrium points are asymptotically stable. Moreover, a minimum level of vaccination has been defined. For the vaccination level less than the minimum level, increase in the vaccination level results in decrease of the proportion of infected individuals in the corresponding equilibrium point. On the other hand, for the vaccination level greater than the minimum level, increase in the vaccination level results in decrease the proportion of susceptible individuals in the corresponding equilibrium point. Furthermore, when vaccination level is greater than the minimum level, it is found that the time needed for the disease to extinct is shorter.
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