Judul: Stability Analysis of the Bilinear Incidence and Half-Saturated Incidence Models in the Avian Influenza Epidemic
Abstrak: Flu burung H5N1 adalah contoh patogen yang diketahui sebagai penyebab terjadinya wabah penyakit pada manusia. Penelitian ini berfokus pada pemilihan strategi pengendalian penyakit flu burung dengan menggunakan Model Insidensi Bilinear (BI) dan Insidensi Setengah Jenuh (HSI). Tujuan penelitian ini adalah merekonstruksi model, menganalisis sifat kestabilan titik tetap dengan menggunakan fungsi Lyapunov, dan melakukan simulasi numerik dengan beberapa perlakuan. Dalam penelitian ini ditunjukkan bahwa parameter yang berpengaruh adalah parameter populasi yang menerapkan perlindungan diri dan efektivitasnya, parameter tingkat isolasi unggas yang terkena flu burung, serta parameter cakupan vaksin dan efektivitasnya. Peningkatan nilai parameter ini dapat menurunkan bilangan reproduksi dasar sehingga kondisi bebas penyakit dapat terjadi. Sehingga pengontrolan dinamika penyebaran penyakit dapat dilakukan dengan meningkatkan nilai parameter tersebut., The H5N1 avian influenza is an example of a pathogen that is known to cause human disease outbreaks. This study focuses on selecting avian influenza control strategies using Bilinear Incidence (BI) and Half-Saturated Incidence (HSI) Models. This study aims to reconstruct the model, analyze the stability of a fixed point using the Lyapunov function, and perform numerical simulations with several treatments. This study shows the parameters that influence are the parameters of the population that apply personal protection and its effectiveness, the parameters of the rate of isolation of birds with avian influenza, and the parameters of vaccine coverage and its effectiveness. Increasing the value of this parameter can reduce the basic reproduction number so that disease-free conditions can occur. Hence, controlling the dynamics of disease spread can be done by increasing the value of these parameters.
Keyword: avian influenza, bilinear incidence, H5N1, half-saturated incidence, Lyapunov function

Judul: Analisis Model Pandemik dan Prepandemik Avian Influenza pada Populasi Manusia
Abstrak: Avian influenza is a viral disease caused by a virus within the subtype of H5N1 in which its transmission caused by birds or human. In human population, transmission process of avian influenza is discussed in the model called: bird model, prepandemic model and pandemic model. The bird model has two equlibrium points. These are saddle disease free equilibrium and stable endemic equilibrium. The endemic equlibrium occurred when the reproduction number of avian influenza is greater than one. In the endemic equilibrium, avian influenza may infect both bird and human. The prepandemic model has two equilibrium points. These are avian influenza dominant equilibrium and human influenza dominant equilibrium. The human influenza dominant equilibrium occurred when the reproduction number of human influenza is greater than one. The pandemic model has one pandemic equlibrium. The human influenza pandemic occurred when the ratio of human influenza invasion, pandemic invasion and the reproduction number of human influenza is greater than one, respectively. The avian influenza pandemic occurred when the ratio of human influenza invasion, pandemic invasion is less than one and the reproduction number of avian influenza greater than one, respectively.
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Judul: Membran Komposit Kitosan-Natrium Alginat untuk Aplikasi Direct Methanol Fuel Cell
Abstrak: Composite of chitosan and sodium alginate can be utilized as base material of proton exchange membrane (PEM). The composite membranes were produced by various concentrations of chitosan-sodium alginate, namely 3:3, 3:4, 3:5, 3:6, 4:3, 5:3, and 6:3 (% b/v). The composites were characterized by using Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), and were tested for the performance as PEM from the proton conductivity obtained by using impedance spectrometer. The FTIR spectrum indicated the NH3C group at 1637.29 cm-1 and symmetrical COO group at 1253.68 cm-1 indicating interactions between chitosan and sodium alginate. SEM micrographs showed that the composite membrane was nonporous. Composite membrane with 3:5 chitosan-sodium alginate composition had the highest proton conductivity, namely 9.594 × 10-7 S/cm. Based on this research results, chitosan-sodium alginate composite membrane can be applied well in direct methanol fuel cell system.
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