The thermal shrinkage technique, which uses shrinkage strain to determine weld distortion, shows promise as a simple simulation for predicting the weld distortion of large welded structures. To date, ...there has not been adequate research on how to set input data based on welding conditions. In this work, we perform a parametric study using thermal shrinkage technique in which we vary the input data to investigate the optimum setting method. To compare angular distortion obtained by the thermal shrinkage technique, Metal active gas welding was conducted under five welding conditions and thermal elastic-plastic analysis was conducted under the same welding condition. Under all five conditions, the angular distortion obtained by the thermal shrinkage technique accurately reproduced that obtained by experiments and by thermal elastic-plastic analysis. We found that the optimum input data settings were the shrinkage strain of −0.012 and a shrinkage zone in which the maximum temperature reached 500°C or more. From the results, the similarity and the difference between the characteristics of angular distortion in the thermal shrinkage technique and that in the thermal elastic-plastic analysis was discussed based on the inherent strain and the moment. Moreover, the way in which inherent strain based on the both-ends-fixed-bar analogy occurred can explain the agreement in angular distortion in the case of the optimum input data settings. Our results demonstrate that a suitable setting method of input data has been established.
Addition to media of yeast extract, a vitamin mixture containing vitamin B{sub 12}, biotin, pyridoxamine, and p-aminobenzoic acid, or vitamin B{sub 12} alone enhanced formation of ethanol but ...decreased lactate production in the fermentation of cellulose by Clostridium thermocellum I-1-B. A similar effect was not observed with C. thermocellum ATCC 27405 and JW20.
An ethanol hyper-producing clostridial strain, I-1-B, was isolated from Shibi hot spring, Kagoshima prefecture and identified as Clostridium thermocellum based on morphological and physiological ...properties. The carbohydrates used as energy sources were glucose, fructose, cellobiose, cellulose and esculin. Fermentation products were ethanol, lactate, acetate, formate, carbon dioxide, and hydrogen. The optimum, maximum, and minimum temperature for growth are about 60, 70, and 47 degrees C, respectively. Optimum pH for growth is about 7.5, and growth occurs at starting pH between 6.0 and 9.0. I-1-B strain has strong tolerance for ethanol and hyper ethanol-productivity. Ethanol concentrations causing 50% decrease of growth yield are 27 and 16 g/liter for I-1-B and ATCC 27405 of C. thermocellum, respectively. The organism was cultured on a medium containing 80 g/liter cellulose at 60 degrees C for 156 h. The culture was fed with a vitamin mixture containing vitamin B12 and mineral salts solution at intervals. In this culture the organism produced 23.6 g/liter (512 mM) ethanol, 8.5 g/liter (94 mM) lactate, 2.9 g/liter(48 mM) acetate, and 0.9 g/liter (20 mM) formate. The molar ratio of ethanol to total acidic products was 3.2. The ethanol productivity of the strain I.1-B is superior to any of the wild and mutant strains of C. thermocellum so far reported
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