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In this paper, the results of a statistical study on inelastic displacement ratio for structures subjected to pulse like near fault ground motions were presented. This study is important because, the results can used for evaluating inelastic displacement demand of structures with known lateral stiffness and strength subjected to near fault ground motions. Inelastic displacement ratio were computed from the response of single-degree-of-freedom systems having 6 level of strength reduction factor when subjected to 61 pulse like near fault records. The influence of period of vibration normalized by period of peak spectral displacement, strength reduction factor, period associated with velocity pulse TP, earthquake magnitude and distance to the source, post-yield stiffness and hysteresis behavior of structure on inelastic displacement are evaluated. Results indicate that strength and stiffness degrading in short period region increase inelastic displacement demands. Finally, a simply equation for estimate the mean of the inelastic displacement ratio for structures subjected to pulse like near fault ground motions is proposed.

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In this paper, the results of a statistical study on inelastic displacement ratio for structures subjected to pulse like near fault ground motions are presented. This study is important because the results can be used for evaluating inelastic displacement demand of structures with known lateral stiffness and strength subjected to near fault ground motions. Inelastic displacement ratio is computed from the response of single-degree-of-freedom systems having 6 level of strength reduction factor subjected to 61- pulselike near fault records. The influence of period of vibration normalized by period of peak spectral displacement, strength reduction factor, period associated with velocity pulse TP, earthquake magnitude and distance to the source, post-yield stiffness and hysteresis behavior of a structure on inelastic displacement ratiois investigated.For more study on the strength and the stiffness degradation effects on inelastic displacement, three type of hysteresis behavior have been considered. The first type iselasto-plastic behavior. Elasto-plastic behavior is generally used to represent the non-degrading hysteretic behavior. Second and the third typesarethe stiffness degrading and the strength-stiffness degrading hysteretic behavior.Results indicate that strength and stiffness degrading in short period region increases inelastic displacement demands. Further the period associated with velocity pulse plays a main role in inelastic displacement and has a significant effect on it. It is found that strain hardening can reduce inelastic displacement relative to system with perfectly elasto-plastic hysteresis behavior. Magnitude and source to site distance have little effects on inelastic displacement. Finally, a simple equation is proposed for estimating the mean inelastic displacement ratio for structures subjected to pulse like near fault ground motions.

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Molecular species identification has become more ubiquitous in diagnostics of insects, particularly in situations where morphological identification is a laborious or time-consuming process. Tetranychid mites are serious agricultural pests. Identification of tetranychid mites is usually arduous and requires a high level of taxonomic expertise because of their minute size, their close morphological similarities as well as limited number of diagnostic characters. Most species of the spider mites of the genus Tetranychus Dufour in Iran are morphologically similar, differing only in the diameter of the aedeagal knob in males. Because this genus contains many important pests, the unambiguous identification of species is crucial for effective pest management. In this study, a single-step multiplex Polymerase Chain Reaction (multiplex PCR) was used to discriminate two predominant spider mite species occurring in greenhouses in Iran: Tetranychus urticae Koch and Tetranychus turkestani (Ugarov and Nikolskii). The single-step multiplex PCR developed here, based on ITS regions, is rapid, reliable, sensitive and relatively simple. The entire identification protocol from DNA extraction to electrophoresis could be completed in four hours. Moreover, it is adequately simple to be implemented in any molecular laboratory.