Judul: Pengaruh Pengeringan Terhadap Rendemen Minyak Jarak Pagar (Jatropha curcas L.)
Abstrak: Drying is a process of reducing the moisture content of the ingredients until a certain moisture content. One of the ingredients that require drying process to preserve its quality is of jatropha seeds. The purpose of drying jatropha seed is to higher produce the most yield. This research to study of drying effect conditions on oil yield of jatropha seeds and finding the proper drying conditions for jatropha seeds. The ingredients used are seeds obtained from jatropha plantation Pakuwon, Sukabumi. This drying process is done by using sunlight and accutition drying machine. Drying using a accutition drying machine by treatment of T = 60 oC, RH = 20%; T = 60 °C, RH = 40%; T = 80 °C, RH = 20%, and T = 60 °C, RH = 40%. The results suggest that the lower of moisture content of jatropha seeds, the higher the yield of oil produced. The greatest yield of oil produced by the dryer berakuisisi at T = 80oC and RH = 20%, while the lowest oil yield occurred in treatments with accutition drying machine at T = 60oC and RH = 40%. Henderson & Pabis model can describe the characteristics of dying with the jatropha seed drying than Lewis's model where the correlation coefficient (r) ranged from 0990 until 0999.
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Judul: Kajian Isotermi Sorpsi Air Biji Jarak Pagar (Jatropha curcas L)
Abstrak: Jatropha seeds storage is an important step that can affect the process of biodiesel production. At jatropha seeds storage, free fatty acid content can be increased so that the oil yield will be reduced. This situation is due to oxidation and hydrolysis reactions that have relationship with water. The existence of water on jatropha seeds is reflected in the water activity (aw). Bell and Labuza (2000) said that oxidation can increased at water activity above 0.3. The relationship between water content with aw is described by the moisture sorption isotherms curves. The objectives of this research is to study the equilibrium moisture content, the best fitted model of moisture sorption isotherms and the relationship between equilibrium moisture content with free fatty acid content of jatropha seeds. The moisture sorption isotherms of jatropha seeds were determined at two different temperatures (30 and 40°C) and ten different water activity (0.14, 0.15, 0.27, 0.37, 0.43, 0.54, 0.68, 0.71, 0.79 and 0.83). Eight models namely the BET, GAB, Halsey, Harkins-Jura, Henderson, Oswin, Smith and Iglesias-Chirife were fitted to the sorption data. The models were compared using the modulus deviation (P) and coefficient of determination (R2). The moisture sorption isotherms were sigmoidal in shape. On the two highest aw 0.79 and 0.83 there was a sharp increase of equilibrium moisture content. The hysteresis phenomena was not occurs between desorption and adsorption process. The moisture sorption isotherm of jatropha seeds decreased with increased in temperature at constant aw. The best fitted model in the range aw from 0.14 to 0.83 was GAB model. Modulus deviation value of GAB model at adsorption 30°C, desorption 30°C, adsorption 40°C and desorption 40°C is 11.3, 12.14, 15.37 and 12.48 respectively. Coefficient of determination value of GAB model at adsorption 30°C, desorption 30°C, adsorption 40°C and desorption 40°C is 0.80, 0.80, 0.70 and 0.85 respectively. Monolayer moisture content resulting from the BET and GAB model was 3.00 to 4.36 (% db). At monolayer moisture content, free fatty acids content were not increased. The free fatty acids content increased with increased in equilibrium moisture content although fluctuating at 30°C. Free fatty acid content in the two highest aw 0.729 and 0.825 tend to increase. This relationship can be more specifically described by polynomial equations.
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Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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