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: Edible film based on carrageenan, bacterial cellulose, and nanocarbon with additional crosslinker Fe2+
Abstrak: Edible film dari karaginan merupakan lapisan tipis yang terbuat dari bahan yang dapat dikonsumsi. Aplikasi edible film pada pelapisan makanan bermanfaat untuk menambah masa simpan makanan dan melindungi makanan dari mikroorganisme berbahaya. Penambahan selulosa, gliserol, nanokarbon, dan penaut silang Fe2+ bertujuan memperbaiki sifat mekanik dan permeabilitas uap air. Nanokarbon pada edible film akan memancarkan warna saat disinari ultraviolet pada panjang gelombang 366 nm. Konsentrasi nanokarbon yang digunakan berturut-turut 0.5%, 1%, 1.5%, dan 2% b/v. Nilai kuat tarik dan permeabilitas uap air meningkat seiring meningkatnya konsentrasi nanokarbon yang diberikan. Penaut silang Fe2+ yang digunakan berturut-turut 1.5%, 3%, dan 5% b/v dengan nilai kuat tarik optimum pada konsentrasi 5%. Keberadaan karaginan dalam film ini ditunjukkan oleh spektrum inframerah pada bilangan gelombang 1234.44 cm-1 yang merupakan ciri khas karaginan, yaitu gugus fungsi fungsi ester sulfat. Kata kunci: karaginan, nanokarbon, penaut silang Fe2+, permeabilitas air, sifat mekanik., Edible film from carrageenan is a thin layer made of food grade materials. Application of edible coating films could increase food product shelflife and protect food from microorganisms. The addition of cellulose, glycerol, nanocarbon, and crosslinker Fe2+ aims to improve the mechanical properties and permeability. Nanocarbon on edible film will flouresence when exposed to UV at a wavelength of 366 nm. The added nanocarbonwere 0.5, 1, 1.5, and 2% w/v. Tensile strength and permeability increased with increasing concentration of nanocarbon. The added cross-linker was 1.5%, 3%, and 5% w/v with the optimum value of tensile strength at 5%. The presence of carrageenan in this film was showed by Fourier transform infra-red in wave number 1234.44 cm-1 which is the characteristic of functional group in carrageenan, namely sulfate esters. Keywords: carrageenan, crosslinker Fe2+, mechanical properties, nanocarbon, permeability.
Keyword: karaginan, nanokarbon, penaut silang Fe2+, permeabilitas air, sifat mekanik

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