Judul: Kajian Model Epidemik SIR dengan vaksinasi Deterministik dan Stokastik dengan Waktu Diskret
Abstrak: SIR dengan vaksinasi merupakan model epidemik yang digunakan untuk memodelkan penyebaran suatu penyakit dalam suatu populasi tertutup dengan memasukkan faktor vaksinasi. SIR dengan vaksinasi terdiri atas tiga subpopulasi, yaitu individu rentan dinotasikan dengan S (susceptibles), individu terinfeksi dinotasikan dengan I (infected), dan individu yang telah sembuh dan kebal terhadap penyakit dinotasikan dengan R (recovered). Model epidemik SIR dengan vaksinasi yang dibahas dalam penelitian ini yaitu model deterministik dan model stokastik. Dari model SIR dengan vaksinasi deterministik diperoleh titik tetap beserta kestabilannya. Dari model stokastik diperoleh peluang transisi dan peluang wabah. Kestabilan titik tetap pada model deterministik bergantung nilai dari bilangan reproduksi dasar. Dari hasil simulasi yang dilakukan baik pada model SIR dengan vaksinasi deterministik maupun stokastik, perlakuan pemberian vaksin cenderung lebih efektif dalam meningkatkan jumlah individu yang sembuh. Sedangkan perlakuan penyembuhan cenderung lebih efektif dalam menurunkan wabah penyakit.
Keyword: SIR, vaksinasi, deterministik, stokasti

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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Judul: Production of Nanocellulose- Polyvinyl Alcohol- Alginate Based Filaments
Abstrak: Oil palm empty fruit bunches (OPEFBs) are solid waste that are produced from crude palm oil extraction. Generally, it contains around 41-46.5% of cellulose, 25.3-33.8% of hemicellulose, and 27.6-32.5% of lignin (Suriyani 2009). Nanocellulose (NC) was isolated from OPEFBs through several treatments, including delignification, bleaching, ultrafine grinding, and ultrasonication. The obtained nanocellulose was processed further into filaments by mixing with sodium alginate and polyvinyl alcohol (PVA). In this project, nanocellulose- PVA- alginate based filaments were produced by wet spinning method with CaCl2 as coagulant solvent. The effect of several formulations and CaCl2 concentration on the morphological, mechanical, and thermal properties of filaments were observed. The results showed that the increasing of NC concentration produced filaments that have better thermal properties and higher crystallinity, but the morphology of filament surface become rougher. The increasing of NC concentration up to 7% also increased the filament mechanical properties. Meanwhile, the increasing of CaCl2 concentration produced filaments that have better thermal properties, smoother surface, and higher crystallinity (up to 10% CaCl2), but with decreasing of mechanical properties (tensile strength) due to some cracks that occured on the surface of filaments with 13% of CaCl2.
Keyword: coagulant solvent, filaments, nanocellulose, oil palm empty fruit bunches, wet spinning