• Title/Summary/Keyword: alternate method of solution

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Technology for the Preparation of Ash-free Coal from Low Rank Coal(LRC) (저등급 석탄으로부터 초청정석탄 제조 기술)

  • Lee, Sihyun;Kim, Sangdo
    • Korean Chemical Engineering Research
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    • v.46 no.3
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    • pp.443-450
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    • 2008
  • Efficient use of low rank coals (LRC) have been investigated as a method to cope with recent high oil price. Among the coals used in industry, lignite and sub-bituminous coals are belong to the LRC, and have abundant deposit and are distributed worldwide, but high moisture contents and self ignition properties inhibits their utilization. In this paper, chemical coal cleaning to produce ash-free coal from LRC has been investigated. Two technologies, that is, UCC(Ultra Clean Coal) process removing ash from coal and Hyper Coal process extracting combustibles from coal were compared with. UCC process has merits of simple and reliable when it compared with Hyper Coal process, but the remaining ash contents werehigher than Hyper Coal. Hyper Coal has ash contents under the 200ppm when raw coal is treated with appropriate solvent and ion exchange materials to remove alkali materials in extracted solution. The ash-free coal which is similar grade with oil can be used as alternate oil in the industry, and also used as a high grade fuel for IGCC, IGFC and other advanced combustion technology.

Path Algorithm for Maximum Tax-Relief in Maximum Profit Tax Problem of Multinational Corporation (다국적기업 최대이익 세금트리 문제의 최대 세금경감 경로 알고리즘)

  • Sang-Un Lee
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.23 no.4
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    • pp.157-164
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    • 2023
  • This paper suggests O(n2) polynomial time heuristic algorithm for corporate tax structure optimization problem that has been classified as NP-complete problem. The proposed algorithm constructs tax tree levels that the target holding company is located at root node of Level 1, and the tax code categories(Te) 1,4,3,2 are located in each level 2,3,4,5 sequentially. To find the maximum tax-relief path from source(S) to target(T), firstly we connect the minimum witholding tax rate minrw(u, v) arc of node u point of view for transfer the profit from u to v node. As a result we construct the spanning tree from all of the source nodes to a target node, and find the initial feasible solution. Nextly, we find the alternate path with minimum foreign tax rate minrfi(u, v) of v point of view. Finally we choose the minimum tax-relief path from of this two paths. The proposed heuristic algorithm performs better optimal results than linear programming and Tabu search method that is a kind of metaheuristic method.

Residue Determination of Chlorothalonil in Sesame and Soil (Chlorothalonil의 참깨 및 토양중 잔류소장에 관한 연구)

  • Lee, Kang-Bong;Cho, Ill-Kyu;Shim, Jae-Han;Suh, Yong-Tack
    • Korean Journal of Environmental Agriculture
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    • v.9 no.1
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    • pp.15-22
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    • 1990
  • The efects of application time on the persistence of chlorothalonil in sesame plants and its persistence in soil were studied in the field. A procedure was used which permited the analysis of residues of Chlorothalonil (DACONIL 2787) in sesame(Sesamum indicum L.)and soil. The procedure was based on the multiresidue analytical method using an polarized acetonitrile solution or acidified acetone as the extracting solvent. The DACONIL 2787 is separated from the fat in the extracts by using an activated alumina and Florisil chromatogaphic column. Residues of DACONIL 2787 were determined by subjecting the alternate eluate from the Florisil column to gas chromatographic analysis(ECD). Residue of chlorothalonil in sesame are proved to 0.06 ppm for six sprays, 3rd day before harvest The half-life of chlorothalonil in soil proved to be 8.9 days and residues of chlorothalonil was only 0.03 ppm 100 days after application of 15 ppm.

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