Judul: Pembuatan Ester Etil Asam Lemak dari Minyak Kelapa dan Etanol dengan Katalis Abu Sabut Kelapa
Abstrak: Biodiesel is produced through the reaction between oil and alcohol with the help of catalyst which is called transesterification. In this research is used ethanol from alcoholic beverage distilation result with coconut fiber ash as catalyst. Ash alkalinity was analysed by titrimetry or indicator titration. Extraction of ash was done in athanol and water through reflux, heating withouth reflux, and withouth heating. Transesterification was done at room (28 °C) and (64 °C) tempetature to shown the effect of temperature. The effect of time was determining with variation of time 2, 4, 6, and 8 hours. The potential of coconut fiber ash as catalyst was determining with ratio of oil:ethanol (1:6) that reacted at temperature 60 °C for 2 hours in methanol and ethanol. The potential of ethanol from alcoholic beverage distilation result was determining with additional water into ethanol (0, 5, 10, 20, 30, 40, and 50%). The quality of oil and ester were determining with measure the saponification and acid number. The capability of water to extract the coconut fiber ash was higher than ethanol. The alkalinity in water was increased by additional of ash weight. While, the alkalinity in ethanol was decreased by additional of ash weight. Hight temperature increased the alkalinity, while reflux decreased the alkalinity. Transesterification more perfect at hight temperature (64 °C) than room temperature (28 °C) and there was no effect on additional time reaction after 2 hours. Coconut fiber ash can be used as catalyst in transesterification because the esther product has same quality with using NaOH catalyst. Ethanol can substitute methanol in transesterification. Water content (28-64%) in ethanol was not effected to saponification number, acid number, esther number, and free fatty acid from the esther product.
Keyword: 

Judul: Pembuatan Biodiesel Karet dan Biodiesel Sawit dengan Instrumen Ultrasonik serta Karakteristik Campurannya
Abstrak: Biodiesel is one of known alternative fuel, obtained by oil processing, for example from rubberseed oil and palm oil. Conventionally, biodiesel obtained by reacted oil with methanol for 1 hour at temperature of 65 oC with mechanical stirring, using homogenous catalyst such as NaOH. Homogeneous catalysts dissolve fully in the glycerol layer and partially in the biodiesel layer during the triglyceride transesterification process. Heterogeneous (solid) catalysts, such as CaO, can prevent contamination, making product separation much easier. Moreover, the reaction time of conventional methods can be shortened by applying ultrasonic energy. This research consists of several stages, aimed to obtain biodiesel yield from transesterification using homogenous and heterogenous catalyst, to produce rubberseed biodiesel and palm biodiesel by applying ultrasonic energy, and then obtain the characteristics of palm biodiesel, rubberseed biodiesel, and mix of both. The result showed that the transesterification process using heterogenous catalyst need longer time and give the lower biodiesel yield than the transesterification using homogenous catalyst. Ultrasonic transesterification of palm oil gives a greater yield then the conventional stirring methods, which ultrasonic transesterification yield range between 96.52% to 98.03% and the acid number range from 0.50 mg KOH/g sample to 0.63 mg KOH/g sample. Ultrasonic esterification succeeded in reducing acid value of rubber seed oil in a shorter time, which is smaller than acid value by 30 minute conventional esterification. Ultrasonic transesterification only succeeded to form biodiesel from rubberseed oil that has gone through the 30 minutes ultrasonic esterification (78.84% yield) and through an 1 hour conventional esterification (91.55% yield). Rubberseed biodiesel, palm methyl ester, and a blended of both meets the SNI-04-7182-2006 on the characteristics of acid value, density, viscosity, and cloud point. The iodine number of rubberseed biodiesel was still above the standard, but blending palm methyl ester to rubberseed biodiesel can reduce the iodine number of blended biodiesel to meet the standards. Production cost analysis at biodiesel blended (25% palm methyl ester ini rubberseed biodiesel) resulted : ultrasonic methods still more expensive than conventional methods.
Keyword: 

Judul: Implementation of Spatio-Temporal Change Query in Relational Database.
Abstrak: Geographic object changes in various views. Object changes are recorded using a model of static storage. No historical connection between old version data and new version data has been built. For that, a storage model of spatio-temporal queries that can analyze spatio-temporal changes has been developed. The object changes the geometry are grouped according to the taxonomy of Spatio-Temporal Pattern Change. This research has been able to apply the query patterns change including born, expand, merge, contract, split, normal and die. This query based on geometric (area) changes. The implementation of spatio-temporal change queries represents an object changes continuously with easy, change detection is done by comparing two versions of data. Keyword: spatio-temporal change query, spatio-temporal change pattern.
Keyword: