Experimental study of groutability of Super-Micro cement
Based on the similarity theory and the theory of model test, we simulate different opening rock fractures indoors. On account of Super-Micro cement with four different water cement ratios of 0.8, 1.0, 1.5, 2.0 under different water reducer and additive, the experiment is testing the passing rate of Super-Micro cement through the filter with diameters of 0.02mm, 0.05mm, 0.07mm. The test results indicate that the ultimate limit viscosities are 17.1mPa.s, 33.6mPa.s and 624.7mPa.s respectively when the superfine cement passes these three filtrations. After analyzing the influence of grout viscosity on passing rate, that is to say, the bigger the viscosity, the smaller the crack width.
Dam Foundation Grouting
\IDam Foundation Grouting\N provides its readers with background information that will help them deal more confidently and effectively with the design, supervision, and review of grouting practices. It presents a current overview and critical review of grouting practices in the U.S., while going beyond other grouting sources to discuss experiences in the international grouting arena. Avoiding heavy doses of theory, this book concentrates on the practical issues of dam foundation grouting such as: 1) Design considerations; 2) materials and mix design; 3) factors affecting grouting effectiveness; 4) equipment; 5) standard procedures; 6) supervision and inspection of grouting; 7) documentation of operations; and 8) quality assurance. Dam engineers, dam construction engineers, grouting supervisors and inspectors, field personnel of dam safety reviewing agencies, and engineering students will all benefit from this book. \IDam Foundation Grouting\N also offers an extensive list of references which will guide readers to additional sources of information on the subject.
Characterization and gene cloning of a maltotriose-forming exo-amylase from Kitasatospora sp. MK-1785
A maltotriose-forming amylase (G3Amy) from Kitasatospora sp. MK-1785 was successfully isolated from a soil sample by inhibiting typical extracellular α-amylases using a proteinaceous α-amylase inhibitor. G3Amy was purified from the MK-1785 culture supernatant and characterized. G3Amy produced maltotriose as the principal product from starch and was categorized as an exo-α-amylase. G3Amy could also transfer maltotriose to phenolic and alcoholic compounds. Therefore, G3Amy can be useful for not only maltotriose manufacture but also maltooligosaccharide-glycoside synthesis. Further, the G3Amy gene was cloned and expressed in Escherichia coli cells. Analysis of its deduced amino acid sequence revealed that G3Amy consisted of an N-terminal GH13 catalytic domain and two C-terminal repeat starch-binding domains belonging to CBM20. It is suggested that natural G3Amy was subjected to proteolysis at N-terminal region of the anterior CBM20 in the C-terminal region. As with natural G3Amy, recombinant G3Amy could produce and transfer maltotriose from starch.