production of oxytetracycline by an isolated strain of streptomyces rimosus from iranian soil was investigated using a special fermentation medium. a comparative study was performed with standard strain ptcc 1144 using the following parameters optimum growth conditions with respect to time, ph, and different amounts of corn steep liquor. surprisingly, the production yield of the wild strain was...

Experiments were carried out in which the dependence of the fractional softening on temperature, time and strain rate was determined in a 304H stainless steel. Three prestrain ranges were identified pertaining to three different post-deformation softening behaviors: 1) prestraining to below the DRX critical strain: strongly strain dependent softening by SRX alone with softening kinetics control...

Strain induced precipitation in HSLA-100 steel was investigated by conducting hotcompression and relaxation tests at temperature range of 850°C to 1100°C and strain rate of 0.001s-1 to 1s-1. The absence of dynamic recrystallization at temperatures below 1000°C was attributedto the influence of dynamic precipitation. The stress relaxation tests showed that strain inducedprecipitation is possible...

Indentation is a new method for estimating residual stress. The plastic behavior of the materials under study can affect indentation parameters and, thus, influences the results of residual stress measurement. In this paper, the effect of yield stress and work-hardening exponent on the accuracy of residual stress measurements in steels and aluminums was studied. Results showed that, for m...

in classical mechanics, considering hook’s law stress is a linear function of strain. while in strain gradient theory stress is a function of strain and strain differentials. in this paper, novel formulation relating stress and strain and also new boundary conditions are derived based on minimum potential energy principle. in strain gradient theory a length coefficient parameter is defined. thi...

effects of fe and trichoderma harzianum bi strain on plant growth and development of spathiphyllum were investigated. experiments were carried out in an glasshouse and in pots filled with soil, perlite and coco peat (1:1:1) were used as the growing medium. plant roots (seedlings with three leaves) were inoculated with trichoderma (0 and 8% w/w) as media mixture. fe spray (0, 0.75, 1.5, 3 g/l), ...

heat stress is well recognized among the hazardous physical agents that might be present during work. this study aims to compare wbgt index at acclimated and unacclimated people to permissible threshold limit value and study the differences between physiological parameters at them. twenty one healthy men were participated in the study. all of the subjects were monitored in two different weather...