It is aimed to minimize the structure response against the earth vibration by the use of the open loop control system. In such a control, only one predicting neural network is utilized, which estimates only the earth vibration. The neural network is instructed by some recorded acceleration data, and it is able to predict the acceleration variation for the subsequent step. The control force is equal to the product of the mass of each story to its next step acceleration. This control system leads to the approximate minimum response. Moreover, to guarantee the system stability, a linear controller is added to the system. The resulted mixed control system can assure the system stability and also has better performance. Finally, the effect of the structural mass variation on the control system is investigated. The findings show that the effect of the structural mass variation on the mixed control system is smaller than the one by the predicting neural network.

The heart rate deflection point (HRDP) is the heart rate deviation point of the straight line that is defined in the study of the relationship between work and time and it is used as a criterion for the intensity of exercise planning. The purpose of the present study is to review the Methodological approach of heart rate deflection point the new methods for determining this point. In the present study, the dimensions of HRDP methodology were examined in two areas of HRDP-related physiological mechanisms and HRDP determination methods. In the section on HRDP determination methods, determining the basal heart rate, HRDP calculation, and measurement methods, as well as training protocols, were the most important dimensions of methodology in measuring this point. The present study, by examining the findings of previous research, obtained a suitable and integrated summary of the physiological mechanisms associated with HRDP and the methodological dimensions of HRDP. The results indicate that disagreement about the ability of HRDP to determine the anaerobic threshold related to the methodology of HRDP measurement. Infect, it affects the definition of the anaerobic threshold. Therefore, studies on it continue.

Objectives: The aim of this study was to assess and compare the characteristics of commonly used initial arch wires by their load deflection graphs.Materials and Methods: This study tested three wire designs namely copper nickel titanium (CNT), nickel titanium (NiTi), and multi-strand NiTi (MSNT) arch wires engaged in passive self-ligating (PSL) brackets, active self-ligating (ASL) brackets or conventional brackets. To evaluate the mechanical characteristics of the specimens, a three-point bending test was performed. The testing machine vertically applied force on the midpoint of the wire between the central incisor and canine teeth to obtain 2 and 4mm of deflection. The force level at maximum deflection and characteristics of plateau (the average plateau load and the plateau length) were recorded. Two-way ANOVA and Tukey’s test were used at P<0.05 level of significance.Results: Force level at maximum deflection and plateau length were significantly affected by the amount of deflection. The type of arch wires and brackets had significant effects on force level at maximum deflection, and plateau length. However, the bracket type had no significant effect on the average plateau force.Conclusion: With any type of brackets in deflections of 2 and 4mm, MSNT wire exerted the lowest while NiTi wire exerted the highest force level at maximum deflection and plateau phase. The force level at maximum deflection and the plateau length increased with raising the amount of primary deflection, however the average plateau force did not change significantly.

A theoretical study has been carried out on sandwich beams strengthened mechanically by two external steel plates attached to their tension and compression sides with so-called ‘‘shear connectors ‘‘. This study is based on the individual behaviour of each component of the composite sandwich section (i.e. reinforced concrete beam and upper steel plate and lower steel plate). The approach has been developed to simulate the behaviour of such beams, and is based on neglecting the separation between the three layers; i.e., the deflections are equal in each element through the same section. The differential equations reached were solved analytically. Deflection was calculated by using the approach for several beams, tested in two series, and close agreements were obtained with the experimental values. Furthermore, the interaction efficiency between the three elements in a composite sandwich beam has been considered thoroughly, from which the effect of some parameters, such as plate length upon the behaviour of such beams, were studied.

Thin plates in semi-supported steel shear walls (SSSW) buckle under small lateral loads, and this buckling leads to deflection (out-of-plane displacement) in the plate. The onset of buckling at small lateral loads causes the wall plate to exhibit elastic post-buckling behavior over a wide range. For structural and architectural engineers, knowing the amount of plate deflection under different loads is crucial. Therefore, investigating the variation of lateral load with respect to the corresponding deflection in the elastic post-buckling region is of significant importance. In previous research, the von Kármán plate equations have been solved using the Galerkin method to obtain the displacement field of the wall plate in the elastic post-buckling region. Utilizing the ultimate shear capacity, a bilinear idealization of the lateral load-horizontal displacement curve of the wall has been approximated, and a relationship for the elastic stiffness of these walls has been presented. In this paper, using the results obtained from solving the von Kármán equations for different walls (variations in width, height, plate thickness, and changes in the secondary column), the deflection of the wall plate in the elastic region is obtained, and the load-deflection curve in this region is plotted. Furthermore, a practical relationship is presented for estimating the maximum elastic deflection of the wall plate (the maximum deflection corresponding to the first yield point of the wall plate), using machine learning and applying linear regression techniques.

Modified continuum models have been the essence of much attention in nanomechanics through their computational efficiency and the capability to produce accurate results which are comparable to the atomistic models ones. As the dimensions of a structure approach to the nanoscale, the classical continuum theory has not the capability to predict the behavior of nanostructures due to the size-dependent of their properties which is known as size-effects. In this work, the bending behavior of nanobeams with common sets of boundary conditions is investigated using state-space modeling on the basis of nonlocal beam theories. Both uniform load and point load are considered in this study. To this end, Eringen’ s equations of nonlocal elasticity are incorporated into the classical beam theories namely as Euler-Bernoulli beam theory (EBT) and Timoshenko beam theory (TBT). The maximum deflection of nanobeams corresponding to each set of boundary conditions is obtained using state variables and matrix algebra. The results are presented for different geometric parameters, boundary conditions, and the values of nonlocal parameter to show the effects of each distinctly. It is found that the non-dimensional maximum deflection corresponding to all boundary conditions and both loading cases will be increased for higher values of nonlocal parameter which show this fact that with increasing the nonlocal parameter, the stiffness of nanobeam decreases.

The response of thin steel plates subjected to gaseous mixture detonation loading is investigated analytically to determine the possible permanent deformation of center of steel plates clamped in triangular clamping frames. Deformation profiles of plates with different thicknesses under various pre-detonation pressures are investigated which shows large plastic deformations with the maximum deformation happening at the center of mass of the triangular plate. By adopting an energy method approach developed earlier for circular plates, and incorporating a newly developed condition, upper bounds are obtained for the center of mass deformation of the triangular plate. Besides, some important parameters, including plate thickness and yield strength were studied to show the exposed area effect on the deformation profile. The results from analytical studies demonstrate a good agreement compared with experiments and show that the center of mass displacement decreases greatly with involving thicker plate and strain rate influence. Energy method as a useful tool reveals that that midpoint deflection was decreased by the smaller size of the exposed area of the plate.