Judul: Uji Karakteristik Minyak Nyamplung dan Aplikasinya Pada Kompor Tekan
Abstrak: In a rural area, tamanu oil is potential to produce energy which is able to replace kerosene as fuel in a pressure stove. To replace kerosene, tamanu oil must meet the likely criterias with kerosene. One of the most important criterias is in the matter of viscosity. Tamanu oil has higher viscosity than kerosene. Heating was done to decrease the viscosity of Tamanu oil. One of many ways to determine that the viscosity criteria of tamanu oil has been nearly equal to the viscosity of kerosene is by studying spraying criteria of tamanu oil. The purpose of this research was to determine and analyze the spraying criteria of tamanu oil in a pressure stove. This research also tested modified burner designed by Lestari (2011). Spraying testing was done by giving a treatment to tamanu oil in a certain temperature. From the testing result, tamanu oil had the nearly equal characteristic with the spraying kerosene when the temperature of tamanu oil reached ± 150oC. In this temperature, diameter and spraying angle of tamanu oil was 65,67 mm and 12.40o. Whereas, diameter and spraying angle of kerosene without heating treatment was 66,75 mm and 12.60o. According to Lestari (2011), heating must be done until the temperature of tamanu oil reached ±161.81oC, so that the viscosity of tamanu oil reached 5 cP or equal with the kerosene. From the result of the modified burner testing, apparently burner in a pressure stove could heat tamanu oil to reach 164.7oC temperature. Thus, we could conclude that modified burner in a pressure stove can decrease the viscosity of tamanu oil to reach a nearly equal with kerosene.
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Judul: Uji Karakteristik Minyak Nyamplung untuk Modifikasi Kompor Bertekanan
Abstrak: Tamanu (Calophyllum inophyllum L.) has potential as a biofuel producer crop. Tamanu oil has a high viscosity compared with kerosene. Tamanu oil viscosity must be lowered to the equivalent of kerosene to be applied as a substitute for kerosene, especially in pressure stove. In pressure stove, preheating can reduce the viscosity of fuel to achieve the desired viscosity to be sprayed and burned well. Nowadays, pressure stoves generally are made for kerosene fuel. so that, the pressure stove needs to be modified by considering the preheating stage. Thus, the tamanu oil can be used in the modified pressure stove as a subtitute of kerosene. The objective of the study were (1) to simulate the temperature and viscosity change in relation to the length of heating oil pipeline, (2) to modify the heating oil pipeline based on the simulation result, and (3) to test the performance of modified heating oil pipeline. The simulation results show that the oil should be heated to 161.81 °C to obtain the viscosity of tamanu oil close to the viscosity of kerosene, which is using the heating pipe element along the 25 cm. The tamanu oil spraying diameter is 65.67 mm, and the spraying angle is 12.49o. While kerosene as a control has a spraying diameter of 66.75 mm, and the spraying angle is 12.69o. The increasing of spray diameter to temperature follows the equation d = 0.435T + 2.552, with determinant coefficient of 0.961. While the increasing of spray angle to temperature follows the equation θ = 0.082T + 0.51, with determinant coefficient of 0.961. The increase in diameter and angle of spray with increasing oil temperature, due to the increasing temperatures will further lower the viscosity value, surface tension, and density of tamanu oil. According to Ing et al. (2010), viscosity, surface tension, and density are three fluid properties that are influential in forming the droplet. This oil heating element can heat the tamanu oil until 168.5 oC and 164.7 °C for two different data retrieval conditions.
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Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular