concrete is one of the most widely used materials in construction industry. many large and important structures such as power plants, bridges, dams and buildings employ concrete as main material. propagation of crack is considered one of the main reasons in failure of concrete structures. the process of formation and crack growth is one of the major and complex issues in concrete, because concr...

A Pseudomonas aeruginosa mutant derived by random mutagenesis with N-methyl-N¢-nitro-N-nitrosoguanidine, producing high levels of the rhamnolipid biosurfactants was selected on Siegmund-Wagner (SW) plates. The mutant designated P. aeruginosa PTCC1637 produces rhamnolipids at concentrations 10 time more than parent strain. NMR analysis and surface tension measurement showed that the biosurfactan...

the critical temperatures of a thermomechanical process have a great importance for the final microstructure and mechanical properties of high strength low alloy steels. in this study, the average scheduling was used to determine the critical temperatures of api x70 steel. this steel is extensively used in iran for large diameter, high-pressure gas transportation pipelines as well as the oil tr...

Engineers have a range of methods to estimate the fatigue life under multiaxial conditions. Each of these predictive methods is generally subjected to restrictions, related to the inherent simplified assumptions. The objective of this paper is to evaluate the validity of commonly used multiaxial fatigue criteria for different multiaxial loading conditions. The best criterion is identified throu...

a pseudomonas aeruginosa mutant derived by random mutagenesis with n-methyl-n¢-nitro-n-nitrosoguanidine, producing high levels of the rhamnolipid biosurfactants was selected on siegmund-wagner (sw) plates. the mutant designated p. aeruginosa ptcc1637 produces rhamnolipids at concentrations 10 time more than parent strain. nmr analysis and surface tension measurement showed that the biosurfactan...