Judul: Karakteristik Kimia Serat Buah Kapuk sebagai Bahan Penyerap Minyak
Abstrak: Kapok fiber (Ceiba pentandra) are naturally hydrophobic and oleophilic fiber that would be usefull for oil adsorbent. This research examined of chemical composition, oil sorption capacity and its selectivity of natural and ethanolbenzene extracted fibers. Kapok fibers were taken from Madura-East Java, Pati- Central Java, and Bogor-West Java. Based on the chemical composition, kapok fibers contained holoselulosa 83.04-84.16%, alfa-selulosa 37.43-40.26%, lignin klason 13.24-16.25%, etanol-benzena solubility 1.02-1.17%, cold water solubility 0.63-0.77%, hot water solubility 4.14-4.62% and NaOH 1% solubility 19.49- 26.47%. Adsorption capacity of natural kapok fiber was in range of 30.70 to 63.20 g/g fiber, while extracted kapok fibers exhibited oil adsorption of 26.62 to 50.74 g/g fibers. Dissolution of oleophilic extractives substances seemed that was responsible for lower oil adsorption capacity. Naturally, kapok fiber has a very high selectivity to adsorb oil than that of water, therefore kapok fibers could be promoted as an oil adsorbent material with a high selectivity in the oil-water system.
Keyword: kapok fibers, oil adsorption, oleophilic, hydrophobic, chemical components

Judul: Karakteristik Kimia Kulit Buah Kapuk Randu sebagai Bahan Energi Biomassa
Abstrak: Kapuk fruit’s hull is one of the potential biomass as an alternative renewable energy. The aims of this research is to characterize kapuk fruit’s hull for biomass energy resources based on the analysis of its chemical components (holocellulose, α-cellulose, hemicellulose, lignin, and extractives contents) and proximate analysis (moisture content, volatile matter, ash, fixed carbon, and calorific value). Kapuk fruit’s hulls samples were taken from West, Central, and East Java. Calorific value of kapuk fruit’s hull positively correlated with lignin, extractives, and fixed carbon, however it negatively correlated with holocellulose, hemicelluloses, ash and volatile matter. Generally, kapuk fruit’s hull has good characteristics for biomass energy. Based on the chemical characteristics and calorific value, kapuk fruit’s hull from West Java is better than that from Central and East Java.
Keyword: proxymate analysis., chemicals component, calorific value, biomass energy, kapuk fruit’s hull

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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