Judul: Aktivitas Antioksidan Lignin dari Lindi Hitam Kraft Berbahan Baku Kayu Eukaliptus
Abstrak: Kraft black liquor is produced from kraft process as byproduct. Lignin is the highest component in this black liquor, approximately 46% of the total solid. Lignin can be isolated from black liquor by precipitation using H2SO4 20% (w/v) until pH of 2. Klason method was used to purify lignin through hydrolysis using H2SO4 72% (w/v) to eliminate polysaccharides. The observed parameters were yield, molecular weight, phenolic hydroxyl content, functional groups analysis by infrared spectrophotometer, and testing the antioxidant activity of lignin. The phenolic hydroxyl content of 2.40%, respectively. Vibration of aromatic ring and deformation of C-H indicated that qualitatively lignin was present. Antioxidant activity of lignin was tested with DPPH method (1,1-diphenyl-2-picrylhydrazyl) as a free radical, measured using UV-Vis spectrophotometer at wavelength 515 nm. BHT (buthylated hydroxyltoluene) was used as a positive control. Percentage inhibition was plotted as a lignin concentration function. From the resulting graph can be determined lignin concentration required to reach 50% of percentage inhibition as the IC50. The IC50 was 43 ppm, which is less than 50 ppm, meaning that the eucalypt kraft lignin is potential as an antioxidant.
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Judul: Uji aktivitas antioksidan lignin dari tandan kosong kelapa sawit
Abstrak: The increasing oil palm plantation will increase the amount of oil palm production. One of the solid waste from oil palm industry is empty fruit bunch (EFB) that contain lignocellulose. This research used lignin content in EFB as an antioxidant. Lignin delignification from EFB was done by pulping organosolv method using ethanol. Lignin antioxidant activity was characterized with DPPH method (1,1-diphenyl-2-picrylhydrazyl) as free radical, measured as IC50 (inhibition concentration 50%). Lignin yield was 9,09%; lignin content 76,57%; and fourier transform infrared (FTIR) spectrum indicated the lignin. Phenolic hydroxyl and molecular weight lignin were also determine the lignin antioxidant activity. This result pointed out that the lignin have phenolic structure of type 2 and 3 each 0,4% and the molecular weight is 4005 g/mol. Butylated hydroxytoluene (BHT), a commercially chemical antioxidant, was used as a positive control. The IC50 of lignin is 50,2 ppm, while IC50 that of BHT is 1883 ppm. This result shows that antioxidant activity of lignin is higher than that of BHT.
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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.
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