Judul: Edible Film dari Perpaduan Karaginan, Selulosa Bakteri, dan Nanokarbon dengan Penaut Silang Asam Sitrat
Abstrak: Edible film is a film made of food grade materials. The film has mechanical properties and can act as a barrier so that it can prolong the shelf life of food products. Carrageenan is a base material of film derived from seaweed (Eucheuma cottonii). Addition of glycerol, bacterial cellulose, nanocarbons, and citric acid were used as compatibilizers to improve the mechanical properties of the carrageenan film. The optimum composition of edible film composed of glycerol, bacterial cellulose, nanocarbon 1.5%, and citric acid 10% increased tensile strength up to 160% and decrease of water vapor permeability up to 42% as compared to the carrageenan film. Tensile strength and water vapor permeability values met the standard for edible film as food packaging. The result of infrared spectrum showed the formation of the new functional groups on 1717 cm-1 that caused by the addition of citric acid crosslinker. Luminescence of nanocarbon can be detected using ultraviolet light at wavelength of 366 nm with the presence of blue color
Keyword: Bogor Agricultural University (IPB), water vapor permeability, nanocarbon, mechanical properties, citric acid crosslinker, carrageenan

Judul: Film Edibel Berbahan Dasar Karaginan dengan Tambahan Tepung Porang (Amorphophallus onchophyllus) dan Selulosa
Abstrak: Edible film is thin layer made of food grade materials and increase shelf life of food product. Carrageenan derived from seaweed (Euchema cottoni) is polysaccharide that can be used for producing edible film. Konjac flour, cellulose, and glycerol were added as compatibilizers which can improve physical properties of the edible film. The added konjac flour were 2.5, 5.0, 7.5, 10.0, and 12.5% b/v. Cellulose and glycerol used were 0.1 and 0.75 g, respectively. Addition of konjac flour less than 10% decrease the tensile strength up to 2.87 MPa, in contrast to addition of 12.5% that increased the tensile strength of the film up to 5.60 MPa. The film containing 12.5% konjac flour showed the highest elongation (42.09%) and the lowest water vapor permeability (0.0423 ng m m-2 s-1 Pa-1). Infra red spectra of the films showed no new functional group formation. Thermal analysis showed that all films were decomposed by exothermic and endothermic reaction
Keyword: water vapor permeability, mechanical properties, konjac flour, cellulose, carrageenan

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model