Judul: Biopellet Characterization of Arabica Coffee  Grounds and Teak Sawdust as A Result of Torrefaction
Abstrak: Limbah ampas kopi arabika dan serbuk gergaji kayu jati memiliki potensi untuk dijadikan substitusi energi yang bersifat keberlanjutan. Salah satu pemanfaatannya adalah dengan menjadikan biopelet yang ditingkatkan mutunya melalui proses torefaksi. Penelitian ini bertujuan untuk menganalisis karakterisasi biopelet hasil torefaksi pre-treatment (A) dan post-treatment (B). Biopelet dibuat dengan menggunakan pelletizer tipe flat dies dengan formulasi bahan baku 1:1 (perekat 5%), dan pemrosesan torefaksi menggunakan suhu 220 oC (A1 dan B1), 250 oC (A2 dan B2), dan 280 oC (A3 dan B3). Kondisi pre-treatment merupakan torefaksi bahan baku mentah, sementara post-treatment merupakan torefaksi biopelet. Pengujian fisiokimia biopelet mengacu pada SNI 8675-2018 yang mencakup kerapatan, kadar air, kadar zat terbang, kadar abu, kadar karbon terikat, nilai kalor. Pengujian fisik mencakup dimensi, ketahanan, dan hidrofobisitas. Formulasi terbaik pada tiap parameter dicapai oleh perlakuan A3 dengan nilai kerapatan 0,46 g/cm3 , kadar air 3,32%, kadar zat terbang 44,7%, kadar abu 4,75%, kadar karbon terikat 50,55%, dan nilai kalor 25,96 MJ/kg dan perlakuan B3 dengan nilai kerapatan 0,34 g/cm3 , kadar air 3,11%, kadar zat terbang 39,04%, kadar abu 6,97%, kadar karbon terikat 53,98%, dan nilai kalor 25,12 MJ/kg., The potential of Arabica coffee grounds and teak sawdust waste as sustainable energy substitutes by converting them into bio-pellets enhanced through torrefaction. The research focuses on characterizing bio-pellets from pre-treatment (raw material torrefaction) and post-treatment (bio-pellet torrefaction). Using a flat die pelletizer, the bio-pellets were produced with a 1:1 raw material ratio (5% adhesive) and torrefied at 220°C, 250°C, and 280°C. The bio-pellets' physicochemical properties, including density, moisture content, volatile matter content, ash content, fixed carbon content, and calorific value, were evaluated according to SNI 8675:2018 standards. Physical properties such as dimensions, durability, and hydrophobicity were also assessed. The optimal formulations were A3, with a density of 0,46 g/cm³, moisture content of 3,32%, volatile matter content of 44,7%, ash content of 4,75%, fixed carbon content of 50,55%, and a calorific value of 25,96 MJ/kg, and B3, with a density of 0,34 g/cm³, moisture content of 3,11%, volatile matter content of 39,04%, ash content of 6,97%, fixed carbon content of 53,98%, and a calorific value of 25,12 MJ/kg.
Keyword: Biopelet, Ampas kopi arabika, serbuk gergaji kayu jati, torefaksi pre-treatment dan post-treatment, bio-pellets, arabica coffee grounds, teak sawdust waste, pre-treatment  and post-treatment torrefaction

Judul: Utilization of Biodiesel Transesterification Waste as an  Additive to Improve the Quality of Biopellets
Abstrak: Energi alternatif yang potensial untuk dikembangkan salah satunya yaitu energi berbahan dasar limbah, seperti limbah biodiesel, sampah daun kering, dan kertas bekas dengan mengolahnya menjadi biopelet. Pengoptimalan pemanfaatan limbah biodiesel sebagai aditif merupakan upaya yang dapat dilakukan untuk meningkatkan mutu, terutama nilai kalor biopelet. Penelitian ini bertujuan membuat, melakukan pegujian mutu dan analisis karakteristik biopelet sebagai energi bahan bakar alternatif yang ramah lingkungan. Perbandingan formulasi bahan yang digunakan yaitu A1 sebagai kontrol (100% daun kering), A2 (70% daun kering : 20% limbah biodiesel : 10% kertas), A3 (65% daun kering : 25% limbah biodiesel : 10% kertas), A4 (60% daun kering : 30% limbah biodiesel : 10% kertas), A5 (55% daun kering : 35% limbah biodiesel : 10% kertas), dan A6 (50% daun kering : 40% limbah biodiesel : 10% kertas). Parameter nilai mutu biopelet mengacu pada SNI 8675:2018. Formulasi terbaik diperoleh pada perlakuan A6 dengan nilai kerapatan 0,7 g/cm3, kadar air 13,1%, ketahanan 97,6%, kadar zat terbang 58,3%, kadar abu 7,6%, karbon terikat 34,1%, nilai kalor 17,8 MJ/kg, laju pembakaran 1,42 kg/jam, dan rasio energi sebesar 3,577 yang menunjukkan energi hasil produk biopelet lebih tinggi dari keperluan energi untuk proses produksinya (energi listrik dan manusia). Penambahan limbah biodiesel hasil samping transesterifikasi berpengaruh positif dalam meningkatkan mutu biopelet, terutama pada nilai kalor, karbon terikat, kerapatan dan ketahanan., One of the potential alternative energies to be developed is waste-based energy, such as biodiesel waste, dry leaf waste, and used paper by processing them into biopellets. Optimizing the utilization of biodiesel waste as an additive is an effort that can be made to improve quality, especially the calorific value of biopellets. This study aims to manufacture, conduct quality testing and analyze the characteristics of biopellets as an alternative fuel energy that is environmentally friendly. Comparison of the formulation of the ingredients used, namely A1 as a control (100% dry leaves), A2 (70% dry leaves: 20% biodiesel waste: 10% paper), A3 (65% dry leaves: 25% biodiesel waste: 10% paper), A4 (60% dry leaves : 30% biodiesel waste : 10% paper), A5 (55% dry leaves : 35% biodiesel waste : 10% paper), and A6 (50% dry leaves : 40% biodiesel waste : 10% paper ). The parameters for the quality value of biopellets refer to SNI 8675:2018. The best formulation was obtained in A6 treatment with a density value of 0.7 g/cm3, moisture content 13.1%, durability 97.6%, volatile matter content 58.3%, ash content 7.6%, bound carbon 34.1%, calorific value 17.8 MJ/kg, combustion rate 1.42 kg/hour, and an energy ratio of 3.577 which indicates that the energy produced by the biopellet product is higher than the energy required for pelletizing process (electrical and human energy). The addition of biodiesel waste as a by-product of transesterification has a positive effect on improving the quality of biopellets, especially on calorific value, bound carbon, density and durability.
Keyword: biomassa, biopelet, daun kering, kertas bekas, limbah biodiesel

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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