Judul: Characteristics of Polyester-Coconut Fiber Composite Board with the Addition of Sorghum Bagasse Powder
Abstrak: Produktivitas hutan Indonesia semakin menurun, sedangkan kebutuhan manusia akan bahan baku kayu semakin meningkat seiring dengan bertambahnya jumlah penduduk. Salah satu solusi untuk mengatasi masalah ini antara lain dengan mengembangkan pambuatan metrial papan komposit. Penelitian ini bertujuan untuk membuat papan komposit polyester berpenguat serat kelapa dengan penambahan serbuk bagas sorgum terhadap kualitas papan komposit polyester. Penelitian ini menggunakan metode dengan 2 faktor yaitu presentase kadar partikel (20%, 30%, dan 40%) dan variasi ukuran mesh sorgum (40-60 mesh dan lolos 60 mesh) dengan kadar matrik resin polyester 70% dan penambahan hardener 3%. Kerapatan target papan komposit polyester 1 g cm-3 . Secara keseluruhan kerapatan papan berkisar antara 1,10-1,15 g cm-3 . Campuran papan komposit polyester-serat kelapa dengan serbuk bagas sorgum dapat meningkatkan sifat fisis, mekanis, dan impak. Kadar partikel hanya berpengaruh nyata pada kekuatan impak papan sehingga dapat meningkatkan nilai kekuatan papan komposit. Ukuran partikel tidak berpengaruh nyata terhadap sifat fisis, mekanis dan impak papan komposit. Papan komposit dengan presentase kadar partikel yang tinggi dapat meningkatkan nilai kuat tarik dan impak pada papan., The productivity of Indonesia's forests is declining gradually everyday, while the human needs for the raw materials such as wood is increasing along with the increasing population. One possible solution for this problem is to develop composite materials manufacturing. The purpose of this study is to make polyester composite boards reinforced with coconut fiber with the addition of sorghum bagasse powder to increase the quality of polyester composite boards. This method uses 2 factors, namely the percentage of particle content (20%, 30%, and 40%) and variations in the size of the sorghum mesh (40-60 mesh and 60 mesh) with a matrix content of 70% polyester resin and the addition of 3% hardener. The target density of polyester composite board is 1 g cm-3 . Overall board density ranges from 1,10- 1,15 g cm-3 . A mixture of polyester-coconut fiber composite board with sorghum bagasse powder can increase the value of physical, mechanical and impact properties. The particle content has significant effect on the impact strength of the board, therefore it can increase the strength value of the board. Particle size has no significant effect on the physical, mechanical and impact properties of the board. Composite boards with a high percentage of particle content can increase the tensile and impact strength values of the boards.
Keyword: olyester, sorghum, coconut fiber, composite board

Judul: Sorghum Bagasse Particleboard Bonded by Bio-Adhesive with Nano-Catalyst Addition
Abstrak: Pengembangan papan partikel bagas sorgum menggunakan perekat hayati dengan penambahan nanokatalis berpotensi menghasilkan papan partikel ramah lingkungan dengan sifat fisis-mekanis yang lebih baik. Penelitian ini bertujuan untuk mengembangkan papan partikel berbahan baku biomassa bagas sorgum dan perekat hayati molase-asam sitrat dengan penambahan nanokatalis seng oksida (ZnO) dan grafena oksida (GO). Papan partikel dibuat dengan kerapatan target 0,8 g/cm3, berukuran 35 x 35 x 0,6 cm3 dan dikempa panas pada suhu 200 ○C selama 10 menit dengan tekanan 10 MPa. Sifat fisis dan sifat mekanis papan partikel dievaluasi menggunakan standar JIS A 5908-2003. Papan partikel berperekat molase-asam sitrat dengan penambahan nanopartikel ZnO merupakan perlakuan terbaik pada penelitian ini. Papan partikel molase-asam sitrat ZnO memiliki kerapatan sebesar 0,79 g/cm3, kadar air sebesar 6,22%, pengembangan tebal sebesar 6,49%, modulus of rupture sebesar 127,16 kgf/cm2 dan keteguhan rekat sebesar 2,26 kgf/cm2. Sifat fisis dan mekanis papan partikel molase-asam sitrat ZnO telah memenuhi standar JIS A 5908-2003. Berdasarkan hasil analisis FTIR diketahui bahwa pada papan partikel bagas sorgum berperekat hayati dengan penambahan nanopartikel telah terbentuk ikatan ester., The development of sorghum bagasse particleboard using bio-adhesive with the addition of nanocatalysts has the potential to produce environmentally friendly particleboard with better physical-mechanical properties. This study aims to develop particleboard made from sorghum bagasse biomass and molasses-citric acid bio-adhesive with the addition of zinc oxide (ZnO) and graphene oxide (GO) nanocatalysts. The particleboard was made with a target density of 0.8 g/cm3, 35 x 35 x 0,6 cm3 in dimensions and hot pressed at 200 °C for 10 minutes under 10 MPa pressure. The physical and mechanical properties of the particleboard were evaluated using the JIS A 5908-2003 standard. Particleboard bonded with molasses-citric acid with ZnO nanoparticles addition was the best treatment in this study. The molasses-citric acid ZnO particleboard has density value of 0.79 g/cm3, moisture content value of 6.22%, thickness swelling value of 6.49%, modulus of rupture value of 127.16 kgf/cm2 and a internal bonding value of 2.26 kgf/cm2. The physical and mechanical properties of molasses-citric acid ZnO particleboard have satisfied the JIS A 5908-2003 standard. Based on the results of FTIR analysis, it is known that the bio-adhesive sorghum bagasse particleboard with the addition of nanoparticles has formed ester bonds.
Keyword: citric acid, molasses, graphene oxide, sorghum bagasse, zinc oxide

Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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