Judul: Kajian Produksi Tanin Bubuk dari Gambir Asalan dengan Pengering Semprot (Spray Dryer)
Abstrak: Gambier extract is a product of gambier plant wich is made from leaf gum and twig gambier plant with certain processing. Main compounds of the gambier extract are pseudotanin catechin and catechutannat acid with the percentage of 7-30% and 22-55%. Catechin and tannin in gambier extract can be purified in order to get products wich have high purity. Some researches were done in the purification of gambier extract related to get pure catechin. However, research for the purification of gambir extract to get pure tannin need to be done. Tannin powder was prepared using drying process with spray dryer. The objectives of this study were to get tannin powder from gambier extract with extraction process and to get the best combination treatment for tannin extraction. This study was done by several factor treatments. They were water temperatures (400C, 600C, dan 800C) and ratio of water and gambier extracts (8:1, 10:1, dan 12:1 v/b). Each treatment in the study used 150 gram gambier extracts. Analysis in this research was done for gambier extract and tannin product. Analysis of gambier extract included proximat analysis and tannin content. Some analysis which were done for tannin product consist of tannin content, moisture content, ash content, color test and insolubility in water content material. The results of analysis which have been done on gambier extract as raw material for tannin powder production have moisture content of 12,36% (wet basis), ash content 12,21% (wet basis), fat content 1,61% (wet basis), rough fiber content 6,16% (wet basis), protein content 3,43% (wet basis), and tannin content 38,45% (wet basis). After extraction process, value of tannin content in tannin product (dry basis) has value from 83% to 98%. Yield of tannin product (dry basis) from purification process has a range value from 16% to 42%. Tannin powder product which were dried by spray dryer has moisture content value (dry basis) between 4% and 6,06%, ash content (dry basis) from 85% to 5,17%, and water insoluble material (dry basis) from 2.99% to 4.43%. Tannin product on color test has hoe degree with average 79.82 which shows yellow color spectrum. Whiteness of tannin product has value between 69.20% and 77.96%. Based on the results, increasing ratio of total water and gambier extract increased yield and tannin content in the product. Generally, increasing temperature of water on tannin extraction increased tannin content in the product. Tannin content and the content of water insoluble material showed the purity level of tannin product. The lower grade of water insoluble material showed smaller value of non tannin material and showed product with better purity. Drying process which used spray dryer could produce tannin powder with uniform grain size. Stability of temperature in drying process could give effects to the preparation of tannin powder like mousiture content and whiteness value. Based on the analysis of variance at α = 0.05, factor of total water and gambier extract ratio did not affect significantly to the value of tannin content, 6 moisture content, ash content, whiteness, and water insoluble material content but it gave significantly effects for the yield value
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Judul: Studi Pemanfaatan Tanin dari Gambir (Uncaria gambir Roxb) sebagai Produk Peluruh dan Pencegah Karat pada Logam
Abstrak: Gambier (Uncaria gambier (Hunt.) Roxb) is a genus of flowering plant species in Rubiaceae family. Part of the gambier utilized is the sap which is extracted and then to be dried. Indonesia is the world largest exporter of gambier in the form of raw material. Gambier has major components namely catechin and tannin. Tanin can be used as rust deactivator. High tannin content in gambier may be used as anti-corrosion material thought corrosion is a problem in the industry. The aims of this study were to add value of raw gambier and to obtain the best product formulas that can remove the rust and protect metal from rust (antirust). Preliminary study was conducted by tannin extraction from raw gambier of Lima Puluh Kota regency, measuring the purity level of tannin which was extracted and proxymat analysis of raw gambier and tannin powder. The main study conducted by creating rust remover and anti-rust solution using two-factors completely randomized design consisting of composition factor of tannins and phosphoric acid. Tannin level used in the solution were 2,5%, 3,33% and 4,17%, while level of phosphoric acid were 2,9%, 5,8% and 8,7%. After obtaining the best composition of phosphoric acid and tannin, then the study continued by making ethanol concentration as variable which were 10%, 13% and 16%. Analysis test of solution effectiveness were rust lost of weight analysis and metal appearance analysis, while for anti-corrosion solution, the analysis of metal appearance analysis and Fourier Transform Infrared (FTIR) were done. The tannin level obtained from the material used was 66,76%. Rusty iron soaked with rust converter formula successfully lost its rust content after six hours soaked. From lost weight analysis, it was known that the addition of tannin or phosphoric acid has a significant effect (α = 5 %) to decrease the weight of rust, but the interaction between tannin and phosphoric acid showed no significant results. The best concentration of tannin, phosphoric acid, and ethanol in the formula were 3,33%, 5,8% and 16% respectively. On the test with anti-rust effectiveness yielded that the metal plate was immersed in 3% NaCl for one day, had experienced corrosion while the previous metal plate coated with anti-rust solution had no corrosion on the surface. After one week, the metal plate was given a protective layer had corrosion in certain points, whereas the metal plate that was not given protective layer had corrosion on all over the surface. Results of Fourier Transform Infrared (FTIR) analysis on a rusty metal plate coated with anti-rust solution for one week showed the presence of tannin shown by several functional groups namely OH, CO, C = C aromatic, and C = O and the reaction between tannin and metals at a wavelength of 1625 cm-1. The present of tanin indicated that gambier tannin could react well with metal so it can be used as anti corrosive product
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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