Judul: Analisis Dinamik Model Matematika Virus Ebola
Abstrak: Pada karya ilmiah ini dibahas model matematik untuk menggambarkan dinamika sistem imun terhadap virus Ebola yang dikembangkan oleh Banton et al. (2010). Model yang akan digunakan adalah model Herz, model Tuckwell, dan model de Boer. ...
Keyword: stability analysis, Herz model, Tuckwell model

Judul: Analyzing the Solutions of Mathematical Models on the Spread of the Ebola Virus Disease
Abstrak: Penyakit virus Ebola adalah penyakit yang disebabkan oleh infeksi virus Zaire ebolavirus yang termasuk dalam filovirus. Model matematika penyebaran penyakit virus Ebola yang dikembangkan oleh Li et al. (2015) melibatkan 4 kompartemen, yaitu Susceptible (S), Exposed (E), Infected (I), dan Treated (T). Pengamatan atas dinamika populasi dan analisis sensitivitas dilakukan terhadap model yang sudah dinondimensionalkan. Pemeriksaan kestabilan dengan menggunakan kriteria Routh-Hurwitz menunjukkan bahwa titik tetap bebas penyakit (ketika Ro < 1) maupun titik tetap endemik (ketika Ro > 1) keduanya bersifat stabil asimtotik lokal. Dari sejumlah parameter yang terdapat dalam model, interaksi antara S dan E (ẞ20) adalah salah satu parameter yang berpengaruh besar terhadap Ro. Simulasi numerik dilakukan dengan menggunakan metode Runge- Kutta orde 4 dan 5, serta metode Runge-Kutta Fehlberg. Ketiga metode menghasilkan solusi numerik yang relatif sama. Namun, metode Runge-Kutta Fehlberg memiliki runtime yang lebih singkat dibandingkan metode Runge-Kutta orde 4 dan 5.
Keyword: Ebola, numerical simulations, population dynamics, Runge-Kutta, sensitivity analysis

Judul: Characteristic of chili drying (Capsicum annum L.) as a natural dyeing cosmetic
Abstrak: Chilli (Capsicum sp.) contains carotenoids, which are a group of natural pigments consist of red, orange or yellow color. Carotenoids can be dissolved in lipid so that they can be applied to oil-based cosmetic ingredients. Therefore, chilli is potential to be developed as cosmetic colorants. However, pungency of red chili needs to be removed because it is irritating and it provides stinging sensation to skin. Red chilli was investigated as a potent material for a cosmetic colourant in this research because it has a nice uniform red color and has a pungency level less than cayenne pepper. The purpose of this research was to investigate the influence of blanching on drying characteristics of red chilli using a tray dryer, determine the proper time of chili blanching in sodium bisulfite solution, examine color changes stability of red chili powder as a cosmetic dye, and analyze the effect of oleoresin extraction on color and pungency level of red chili powder. The results showed that blanching could affect the drying characteristics. Blanching the chilli for 9 minutes prior drying could speed up the drying rate of chilli and thus the drying time, therefore, the chilli achieved the desired moisture content fast. Sodium bisulfite solution of 0.2%, used as the blanching media, could maintain the color well. However, longer time of blanching might cause several pigments soluble in the blanching media. Blanching the chilli for 9 minutes was able to maintain red color after the stability tested and after extraction of oleoresin. Therefore, blanching red chilli in a solution of 0.2% sodium bisulfite for 9 minutes prior drying is concluded as the best treatment to retain the color of red chilli powder
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