Judul: Biopelet Mixed of Bintaro Fruit Biomass (Cerbera manghas) and Coconut Shell (Cocos nucifera L)
Abstrak: Limbah biomassa buah bintaro dapat diolah menjadi bioenergi berupa biopelet. Penelitian ini bertujuan untuk mengetahui karakteristik biopelet campuran biomassa buah bintaro dan tempurung kelapa dengan penambahan tapioka terhadap sifat fisis dan mekanis serta menentukan formulasi komposisi biopelet terbaik. Tahapan penelitian ini meliputi persiapan bahan baku, karakterisasi bahan baku pencampuran dan pencetakan biopelet, serta pengujian karakteristik biopelet. Komposi campuran biopelet terdiri dari A (bintaro dan tempurung kelapa); B (arang bintaro dan tempurung kelapa), C (arang bintaro dan arang tempurung kelapa); D (kontrol untuk masing-masing bahan). Perbandingan bahan dari setiap perlakuan A, B, dan C adalah 80:20, 60:40, 40:60, dan 20:80. Pengujian biopelet didasarkan pada parameter kadar air, kadar abu, kadar zat terbang, kadar karbon terikat, kerapatan, dan nilai kalor sesuai dengan SNI 8021-2014. Hasil perhitungan menggunakan metode perankingan diperoleh perlakuan terbaik adalah formulasi C3 dengan komposisi 40% bintaro dan 60% arang tempurung kelapa (skor 9,07). Bintaro dapat menjadi substitusi 40% dari arang tempurung kelapa, dan telah memenuhi kualitas biopelet terbaik dengan karakteristik yang dimiliki oleh formula biopelet C3 yaitu kadar air 0,49%, kadar abu 3,09%, kadar zat terbang 40,73%, nilai karbon terikat 55,69%, kerapatan 0,76 g/cm3, keteguhan tekan 4,40 kgf/cm2, dan nilai kalor sebesar 6080,5 kal/g., Bintaro fruit biomass waste can be processed into bioenergy in the form of biopelets. This study aims to determine the characteristics of the biopelet mixture of bintaro fruid and coconut shell using tapioca adhesive to physical and mechanical parameter also to determine the best formulation of biopelet composition. The stages of this research include the preparation of raw materials, characterization of raw materials, mixing and forming of biopelets, and testing of biopelet characteristics. Biopelet mixture consists of A (bintaro and coconut shell); B (bintaro charcoal and coconut shell), C (bintaro and coconut shell charcoal); D (control for each ingredient). The ratio of raw materials for each treatment A, B, and C are 80:20, 60:40, 40:60, and 20:80. Biopelet testing is based on parameters of moisture content, ash, volatile substance, fixed carbon, density and calorific value according to SNI 8021-2014. By the ranking method, the best treatment was formulation C3 with a composition of 40% bintaro and 60% coconut shell (score 9.07). Bintaro can be a substitute for 40% of coconut shell charcoal, and has met the best biopelet quality with characteristics of C3 biopelet formula are moisture content 0.49%, ash of 3.09%, volatile substances 40.73%, fixed carbon 55.69%, density 0.76 g/cm3, compressive strength 4.40 kgf/cm2, and a calorific value of 6080.5 cal/g.
Keyword: bintaro, biomass, biopelet, calorific value, coconut shell

Judul: Karakteristik Biopelet Limbah Ampas Tebu dan Batang Singkong
Abstrak: Limbah ampas tebu (bagasse) dan batang singkong merupakan biomassa yang berpotensi menjadi alternatif bahan bakar terbarukan untuk memenuhi kebutuhan energi yang kian meningkat. Penelitian ini bertujuan untuk menganalisis karakteristik biopelet dan menentukan formulasi biopelet terbaik dari campuran limbah ampas tebu dan batang singkong. Pembuatan biopelet menggunakan pelletizer tipe rotary dies dengan perbandingan komposisi bahan baku yaitu A1 (100% serbuk batang singkong), A2 (100% limbah ampas tebu), A3 (20% limbah ampas tebu : 80% serbuk batang singkong), A4 (80% limbah ampas tebu : 20% serbuk batang singkong), A5 (50% limbah ampas tebu : 50% serbuk batang singkong), A6 (65% limbah ampas tebu : 35% serbuk batang singkong), A7 (35% limbah ampas tebu: 65% serbuk batang singkong). Penentuan biopelet terbaik berdasarkan pembobotan dengan tingkat kepentingan parameter dengan bobot tertinggi hingga terendah yaitu nilai kalor, kadar abu, kadar zat terbang, kerapatan, kadar air, dan laju pembakaran. Formulasi terbaik dari campuran kedua bahan baku berdasarkan SNI 8675-2018 didapatkan dari perlakuan A5 dengan rata-rata hasil uji kerapatan sebesar 0,60 g/cm³, kadar air 8,29%, kadar zat terbang 77,63%, kadar abu 4,10%, kadar karbon terikat 9,98%, nilai kalor 17,40 MJ/kg, keteguhan 96,55%, laju pembakaran 3,57 kg/jam, serta suhu pembakaran 761°C., Sugarcane bagasse and cassava stems are biomass waste which have potential as alternative renewable fuels by converting it into biopellets. This research aims to analyze the characteristics of biopellets made from a mixture of sugarcane bagasse and cassava stems waste, and determine the best formulation based on SNI no 8765-2018. A rotary dies type pelletizer has been used to produce the pellets. Pellets formulation was represented by the ratio of raw material composition, they were A1 (100% cassava stem powder), A2 (100% sugarcane bagasse waste), A3 (20% sugarcane bagasse waste : 80% cassava stem powder), A4 (80% bagasse waste : 20% cassava stem powder), A5 (50% sugarcane bagasse waste : 50% cassava stem powder), A6 (65% sugarcane bagasse waste : 35% cassava stem powder), A7 (35% sugarcane bagasse waste : 65 % cassava stem powder). Determination of the best biopellets is based on the scoring with the level of lightness of the parameters with the highest to lowest score is calorific value, ash content, volatile matter content, density, moisture content, and combustion rate. The best formulation obtained from A5 composition (50% bagasse and 50% cassava stem) with average density of 0,60 g/cm³, water content of 8,29%, volatile matter content of 77,63%, ash content of 4,10%, bound carbon content of 9,98%, calorific value 17,40 MJ/kg, durability 96,55%, and combustion rate 3,67 kg/hour, combustion temperature 761°C.
Keyword: biomassa, biopelet, bagasse, batang singkong, pelletizer

Judul: Tinjauan Matematis pada Model Makroskopik dan Mikroskopik Arus Lalu-lintas
Abstrak: Traffic flow phenomenon can be described through mathematical model such as continuous dynamic model with an ordinary differential equation so that it can be solved with integral factors. In this paper three simple models of traffic flow are discussed, i.e, two macroscopic and one microscopic models. Macroscopic model formulates dynamics of the traffic flow that occurs on a large number of vehicles on a road. While the microscopic model explains drivers’ behavior in their interaction with other vehicles ahead, i.e, car-following model. This paper shows the existence of ordinary differential equation found in the traffic flow model and indicates some different representations in the context of the same model. It also reviews a simple model of traffic flow along a single link, which leads to some unexpected results, i.e, it can express the solution model in term of link outflows as well as trip time. In the microscopic model, simulation is done to illustrate the behavior of the drivers with a sensitivity coefficient as a benchmark parameter.
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