Judul: Optimasi Penghambatan Pengendapan Sari Kacang Kedelai dengan Metode Sonikasi
Abstrak: Precipitation occurred in soymilk products were caused by large size particles. Particle size reduction was done by sonication method with ultrasonic waves. The aim of this research are to get condition optimum of sonication time and amplitude with ultrasonic waves to get the effectiveness of particle size soymilk for stability emulsion and to identify the acceptance of soymilk by panelists. There are two factors studied, sonication time and amplitude of the ultrasonic waves. Based on the research, optimum condition when sonication time was 23 minutes and amplitude was 33%. Particle size in that condition was 347.29 nm, where the stability of soymilk was good because precipitation does not occurs during storage. Based on organoleptic test, taste and texture of soymilk with sonication were not different significantly with soymilk without sonication, and was different significantly for appearance.
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Judul: Optimasi Penghambatan Pengendapan Jus Jambu Biji Merah dengan Metode Sonikasi
Abstrak: The guava juice is one kind of beverage product and has benefit as antioxidant. It was found that precipitation still happens to this product on marketplace which consumers are less preferable of precipitation guava juice. Therefore, it is necessary to improve the quality of the guava juice in order to inhibit precipitation. The aim of this research are to identify the effect of sonication time and amplitude ultrasonic wave to the stability of guava juice. Moreover, the purpose of this study is to identify the acceptances of panelist toward product sample applied by best combined of sonication time and amplitude value. Based on the research, the most optimum result determined was amplitude of 23% and sonication time of 50 minute where average particle size of guava juice was 298.48 nm with sonication and 311.78 nm without sonication. The application of sonication on guava juice is not recommended because the result of size particle is not much different. Based on organoleptic test, texture and appearance of guava juice by sonication were not different significantly with any sample without sonication, whereas for the parameter texture was different significantly. Suspension stability test results showed that samples with sonication treatment were better than samples without sonication.
Keyword: particle size, optimal, sonication, precipitation, guava juice

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