Judul: Karakteristik Kimia Kayu Reaksi Ulin (Eusideroxylon zwageri T. et B.)
Abstrak: Reaction wood which formed in hardwood generally has a lower klason lignin content, higher acid soluble lignin content, and higher syringil unit than opposite wood. Ulin wood (E. zwageri) contains high klason lignin and low acid soluble lignin contents which closed to lignin characteristic of softwood. This experimental aimed to study the difference of chemical characteristic of reaction wood (klason lignin content, acid soluble lignin content, and lignin monomer composition) and polysaccharides content which formed in E. zwageri stem. Visually, the reaction wood part was formed in upper side of leaning stem. Klason lignin content in reaction wood part was lower (32.71%) than opposite wood part (33.74%). However, the lowest lignin content was found in the side wood part (28.15%). Lignin of E. zwageri was composed by syringyl and guaiacyl monomer with average of syringil to guaisyl ratio 0,2. Acid soluble lignin content in E. zwageri was very low (0.69%) that positively correlated with the proportion of syringil unit in lignin. Polysaccharide content of reaction wood part (63.66%) was higher than opposite wood part (62.88%), but the highest content polysaccharides presented in the side wood part (64.19%).
Keyword: Polisaccharide, syringil-guaiasyl ratio, lignin, E. zwageri, reaction wood

Judul: Karakteristik Kimia Lignin Sepuluh Jenis Kayu.
Abstrak: Lignin is a chemical component of wood which was concerned in relation to pulping process. The content and reactivity of lignin affect the easiness of delignification in the pulping process. This research aimed to analyze the chemical characteristics of lignin in the ten wood species; which were expressed as total lignin, Klason lignin, acid-soluble lignin, and syringil/guiacyl ratio. Total lignin was defined as a sum of Klason and acid-soluble lignin. Lignin content varied widely between wood species. Klason lignin was 20.51-34.3% and acid-soluble lignin was 0.31-2.8%. Wood species having lower lignin content tend to have higher acid-soluble lignin and syringil/guaiacyl ratios. Consequently, there was clear and positive correlation between acid-soluble lignin and syringil/guaiacyl ratio (R2=0.92)
Keyword: acid soluble lignin, delignification, Klason lignin, monomers lignin, reactivity

Judul: Rancang Bangun Sistem Kemudi Otomatis Traktor Pertanian Berbasis Navigasi GPS (Global Positioning System)
Abstrak: Research about the application of automatic navigation system on agricultural tractors has become one of the important research topics in the last two decades especially in the developed countries where the issue of ‘Precision Farming’ application is considered. GPS has been commonly used as the navigation system of vehicles including tractors. The objective of the research was to develop smart tractor that would work automatically based on GPS navigation for cultivation activity in precision farming. Mechatronic navigation control system for agricultural riding tractor including tractor steering, accelerator, clutch, brake system, and hydraulic control had been successfully developed using microcontrollers. GPS interfacing and data processing were also developed using Visual Basic 6.0 and functioned as the main control system. Field test was done on 40 x 20 m area with tractor velocity 0.6 m/s. The average error of control system was 17.9 cm.
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