Judul: Pengembangan bionanokomposit film berbasisi pati tapioka dan nanopartikel ZnO dengan plasticizer gliserol
Abstrak: Cassava starch is able to form transparent coatings and flexible films without using any chemical additives. However, films made from cassava starch only is poor in functional packaging properties. The main objective of this study was to enhance functional packaging properties of casava starch films by using zinc oxide nanoparticles (ZnO-NPs) as reinforcing agent, and glycerol as plasticizer. Cassava starch/ZnO nanocomposite films were prepared at 4 levels of ZnO-NPs (0.25, 0.5, 1.0, 3.0 % by weight of starch) and 15 % of glycerol by weight of solid (cassava starch + ZnO-NPs). In this study, plasticized starch-ZnO nano-composite filmss were prepared by nanodispersion technique followed by solution casting method, and were analysed to determine its mechanical properties by tensile tests, the glass-transition temperature (Tg) by differential scanning calorimetry (DSC) and antimicrobial properties against three bacterial strains that commonly contaminate food products, e.g. Escerichia coli, Bacillus cereus and Staphylococcus aureus. The improvement in mechanical properties could be achieved with plasticization and ZnO-NPs incorporation. The incorporation of ZnO-NPs 3 % significantly induced antibacterial activities of the cassava starch films against Escherichia coli, Bacillus cereus, Staphylococcus aureus. Moreover, the glass-transition temperature of cassava starch increased with the increasing ZnO-NPs concentrations. Our results suggest that cassava starch films containing ZnO-NPs could be used as antibacterial food packaging material
Keyword: antibacterial packaging, ZnO nanoparticles, nanocomposite films, cassava starch film, Bogor Agricultural University (IPB)

Judul: Pengembangan Bionanokomposit Film Berbasis Tapioka/Nanopartikel Perak dan Tapioka/Nanopartikel Seng Oksida dengan Plasticizer Gliserol.
Abstrak: Cassava starch can be formed into bioplastic film which is transparance as synthetic plastic films. However, pure cassava starch film has some drawbacks such as brittle, poor barrier to water vapour, sensitive to humidity and not stable during the application. The addition of nanoparticles in film was intended to increase the elongation and tensile strength, moisture stability and to provide antimicrobial activity. Meanwhile, the addition of glycerol was intended to increase the plasticity of films so they will not be easily cracked. The main purpose of this research is to elaborate the functional packaging characteristics of bionanocomposites films made from cassava starch with or without silver nanoparticles (Ag-Np) of zinc oxide nanoparticles (ZnO-Np) with glycerol as plasticizer. The addition of nanoparticles was conducted at the amount of 0%, 0,5%, and 1% by weight of the starch, whereas glycerol was used at the amount of 0% and 20% by weight of the solids (starch only or starch+nanoparticles). The value of water vapor transmission decreased significantly with the addition of Ag-Np and ZnO-Np at the concentration of 1% (from 18,0569 g/hm2 to 12,0574 g/hm2) so it enhance the water barrier of the films as packaging materials. The addition of Ag-Np and ZnO-Np at the amount of 1% with 20% of glycerol was also able to inreased the value of elongation (from 1,2% to 88,8%), but decreased the value of tensile strength (from 22,93 MPa to 4,03 MPa). The addition of glycerol gave contrary effect to the tensile strength because it produces low tensile strength values. Moreover, the results show that films made with ZnO-Np had a stronger antimicrobial activity than those made with Ag-Np for both gram positive and gram negative bacteria. In overall, it seems that the formulation of 1% ZnO-Np is the best formulation for developing bionanocomposite film based on cassava starch.
Keyword: Bionanocomposite Films, Silver Nanoparticle (Ag-Np), Zinc Oxide Nanoparticle (ZnO-Np), Cassava Starch, Antibacterial Films

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular