Judul: Pengaruh Campuran Solar dengan Biodiesel dari Residu Minyak Dalam Limbah Padat Spent bleaching earth yang Diproduski secara In Situ terhadap Karakteristik dan Kinerja Mesin Diesel
Abstrak: Production of biodiesel as an alternative fuel to petroleum diesel is necessary because of the limitation availability of petroleum reserves. As one alternative fuel, biodiesel feedstock must be derived from renewable raw materials including vegetable oils. Indonesia has great potential biodiesel feedstock, such as residual oil contain in SBE as solid waste produced by refinery of crude palm oil industry. Utilization of residual oil in SBE as raw material of biodiesel becomes very potential especially since the waste is only treated as disposal material and still contains about 20-30% vegetable oil. This research is aimed to determine the performance of diesel engine used mixture of diesel fuel with biodiesel fuel from residual oil contained in SBE. Biodiesel produced was blended with petroleum diesel fuel at the level of 0% (B0), 10% (B10), 20% (B20), 40% (B40) and 100% (B100). The results of this study, showed that composition of the fuel mixture significantly affect to the parameters of density, viscosity, heat value and flash point and its use in the diesel engine can work normally with all blending ratio of biodiesel fuel with diesel fuel without significant problems. The composition of the fuel mixture B10 is the best mixture of the closest and does not significantly change the value of physico-chemical properties compared to petroleum diesel (B0), the value of density 0.820 g/ml, viscosity 3 cst, heat value 10803.7 cal/g and flash point 103 oC. The maximum power (brake horse power) value of engine running on biodiesel fuel (B100) 20.18 Kw is 10.60% lower than that for diesel fuel (B0) 22.58 Kw.
Keyword: SBE, Engine performance, Biodiesel

Judul: Effect of Addition of Essential Oil Bio-additive to B30 Biodiesel Fuel on Diesel Engine Performance
Abstrak: Biosolar B30 adalah campuran bahan bakar solar dan biodiesel dengan perbandingan 70:30. Permasalahan penggunaan biodiesel meliputi tingginya partikulat, kadar air dan penurunan masa pakai filter sehingga perlu adanya bahan tambahan untuk menangani permasalahan tersebut dengan menambahkan bioaditif. Penelitian bertujuan mengetahui pengaruh penambahan bioaditif dilihat dari karakteristik B30, performa, emisi gas buang mesin diesel dan menentukan formula terbaik dari dua jenis formula yaitu bioaditif A (campuran minyak terpentin, clove terpene, sereh wangi) dan bioaditif B (campuran minyak terpentin, clove terpene, rhodinol). Pengolahan data menggunakan metode deskriptif dan one-way anova pada taraf 95% dilanjut menggunakan uji Least Significance Different. Uji karakterisasi menganalisis beberapa parameter, seperti viskositas, densitas, titik nyala, nilai kalor, kadar air dan partikulat yang telah memenuhi Keputusan Direktur Jenderal Minyak dan Gas Bumi 234.K/10/DJM.S Tahun 2019. Uji performa menganalisis beberapa parameter, seperti nilai torsi dan daya yang mengalami kenaikan sebesar 0,1 – 5% pada bioaditif B dan konsumsi bahan bakar mengalami kenaikan pada bioaditif A dan bioaditif B. Sedangkan parameter pada uji emisi meliputi CO2, NOx, dan Smoke. Nilai emisi NOx dan CO2 lebih rendah dengan menggunakan bioaditif B dan emisi smoke terjadi peningkatan pada bioaditif B., Bio solar B30 is a mixture of diesel fuel and biodiesel with a ratio of 70:30. The problems of using biodiesel, such as high particulates, water content, and decreased duration of the filter so that additional materials are needed to deal with these problems by adding bioadditives. This study aims to determine the effect of adding bio-additives seen from the characteristics of B30, performance, diesel engine exhaust emissions and determine the best formula from two types of formulas, namely bioadditive A (a mixture of turpentine oil, clove terpenes, citronella), and bioadditive B (a mixture of turpentine oil, clove terpenes, rhodinol). Data processing used descriptive methods and one-way ANOVA at the 95% confidence level followed by the Least Significance Different test. The characterization test analyzes several parameters, such as viscosity, density, flash point, calorific value, water content, and particulates, and has complied with the Director-General of Oil and Gas Decree of 234.K/10/DJM.S Year 2019. The performance test analyzed several parameters, such as the torque and power values which increased by 0.1 – 5% in the bio-additive B and fuel consumption increased in bio-additive A and bio-additive B. Meanwhile, the parameters in the emission test included CO2, NOx, and Smoke. The value of NOx and CO2 emissions are lower using bio-additive B, and smoke emission increase with bio- additive B.
Keyword: Biosolar B30, Biodiesel, Bioadditive, Diesel Engine Performance, Characterization test

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf