Azam Najaflou; Mohammad Hossein Sarraf Zadeh; Abbas Gerami
Abstract
Due to the importance of Bacillus thuringiensis (Bt) in the biological fight, it is necessary to optimize its fermentation process and decrease its production cost. Statistical analysis is used not only to optimize fermentation conditions but also to describe and predict the culture behavior. In production ...
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Due to the importance of Bacillus thuringiensis (Bt) in the biological fight, it is necessary to optimize its fermentation process and decrease its production cost. Statistical analysis is used not only to optimize fermentation conditions but also to describe and predict the culture behavior. In production of biological insecticide, one of the important phases is named as sporulation upon which, this work has been particularly focused on. The oxygen and culture time have an important effect on the production cost. So in the current research, the effect of such factors together with cell concentration, toxicity and sporulation has been considered. Regression analysis of the results, obtained in different conditions of aeration, showed that in all experiments, the percentage of total spores and mature spores increase with time. However, when saturated oxygen is used, this increase shows a very slow trend while in the case of interrupted aeration, the sporulation rate is so fast and the culture reached 100 % mature spore at 44th hours of fermentation. Toxicity and insecticide activity of fermentation product is significant even at the beginning of sporulation phase when time factor has only a positive effect at high oxygen concentrations.
Mohammad Ali Lotfollah Yaghin; Ali Reza Mojtahedi
Abstract
Using the statistical characteristics is one of the methods to justify the random nature of the ocean waves. Probability function are used to facilitate the studies of the random waves parameters, such as the surface and height and period of the waves. Since, the force of the ocean waves are the prevalent ...
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Using the statistical characteristics is one of the methods to justify the random nature of the ocean waves. Probability function are used to facilitate the studies of the random waves parameters, such as the surface and height and period of the waves. Since, the force of the ocean waves are the prevalent principal forces on the offshore structures, the assignment of the significant structural responses such as applied inline and transverse forces and also total moment on the piles is the main step for design and construction of the structures.
In this paper, the random waves and their effects on the cylindrical pile will be investigated. These waves have been recorded during some tests which will be illustrated separately. The oscillation of some linear or nonlinear responses of the pile have been discussed statistically and then spectral analysis performed and their extremity amplitude statistical analysis interpreted and prevalent probability functions determined.
