Under far-field long-period earthquake, liquid storage tanks are easy to be failure because of large amplitude liquid sloshing. In this paper, nonlinear contact is used to simulate behavior of SLIDING ISOLATION bearing, nonlinear dynamic equation is used to solve fluid-structure interaction, bilinear material model is used to simulate limiting-device, and 3-D calculation model of SLIDING ISOLATION concrete rectangular liquid storage tank (CRLST) with limiting-devices is established. Firstly, artificial far-field long-period earthquake waves are synthesized based on the existing seismic records. Secondly, dynamic responses of SLIDING ISOLATION CRLST under the action of short-period and far-field long-period earthquakes are studied. Thirdly, effects of bi-directional earthquake and structure size on dynamic responses are investigated. Lastly, displacement control measures are discussed. Results show that far-field long-period earthquakes mainly affect horizontal displacement of structure and liquid sloshing wave height, and SLIDING ISOLATION has obvious control effect on liquid sloshing wave height. Besides, horizontal displacement of structure and liquid sloshing wave height are increased with increase of seismic dimension and structure size. The reasonable designs of SLIDING ISOLATION bearing and limiting-device can solve the problem that the maximum horizontal displacement of SLIDING ISOLATION CRLST may exceed the limit under far-field long-period earthquake.

This study proposed two hybrid controls for response mitigation of adjacent buildings connected by dampers referred as coupled building of which base of taller building being isolated. These controls developed using Magnetorheological dampers in combination with Friction Pendulum System and Resilient Friction Base Isolator respectively named as, Hybrid control 1 and Hybrid control 2. Most effective hybrid control is investigated by comparing the responses obtained by hybrid controls with the responses of same coupled building with Semi-active control. Further, influence of device parameters on performance of hybrid control has been studied through parametric study. The result shows that Hybrid controls are more effective in reducing the responses compared to Semi-active control, however Hybrid control 2 perform more effective not only in response reduction but also in pounding effect.

This paper proposes a 2.4 GHz active mixer without passive inductor for the transceiver system. Taking into account the design requirements of the mixer, a double-balanced down-conversion structure with active inductor and negative resistance is designed. The proposed mixer with 130 nm CMOS technology is designed and simulated using Cadence software at 1.5 V supply voltage. Although we had to compromise conversion gain with linearity, we were able to achieve very high conversion gain with average linearity. Based on the results of post-layout simulations, the conversion gain of 27.57 dB, IIP3 equal to -7.88 dBm, 1-dB compression point equal to -17.34 dBm and IIP2 equal to 44.22 dBm with power consumption of 2.5 mW was obtained for the proposed mixer. The chip size without input and output pads is 95.18 µm × 117.68 µm, which leads to a chip area of 0.0112mm2.

Seismic performance of a symmetrical space frame structure resting on SLIDING bearing with restoring force device is studied considering all the six degrees of freedom. The SLIDING support is modeled as a fictitious spring with two horizontal degrees of freedom. In non-SLIDING phase the horizontal stiffness of SLIDING bearing is considered as very large whereas it is equal to zero during SLIDING phase. The El Centro, Turkey and Mexico earthquakes are adopted as the input motion. The response quantities obtained from the analysis are the acceleration, base shear, bending moment and displacement. In this study, the response of the isolated structure is compared with the response of the structure fixed at the base. Response of the ISOLATION system with restoring force device is also compared with the response of the ISOLATION system without restoring force device. In addition, the effects of coefficient of friction of SLIDING material, time period of the superstructure and the number of storeys on response of structure are also investigated. It is concluded from the study that the SLIDING bearing with restoring force device reduces the earthquake response of the structure. The restoring force device reduces the SLIDING and residual displacements without transmitting additional forces into the structure. Response of the isolated structure varies with the coefficient of friction of SLIDING material, time period of superstructure and number of storeys. Also, there exists an optimum coefficient of friction of SLIDING material for acceleration, base shear and bending moment at which acceleration, base shear and bending moment attains a minimum value.

Seismic response of structures supported on the SLIDING systems to bi-directional (i.e. two horizontal components) earthquake ground motion is investigated. The frictional forces of SLIDING system are assumed to be dependent on the relative velocity at the SLIDING interface with bi-directional interaction. Coupled differential equations of motion of the structure with SLIDING system in two orthogonal directions are derived and solved in the incremental form using step-by step method with iterations. The iterations are required due to dependence of the frictional forces on the response of the system. The response of the isolated system is analyzed to investigate the effects of velocity dependence and bi-directional interaction of frictional forces of SLIDING system. These effects are investigated under important parametric variations such as the fundamental time period of superstructure, period, damping and friction coefficient of the SLIDING system. It is observed that the dependence of friction coefficient on relative velocity of system does not have noticeable effects on the peak response of the isolated system. However, if the effects of bi-directional interaction of frictional forces are neglected then the SLIDING base displacement will be underestimated which is crucial from the design point of view. Further, the bi-directional interaction effects are found to be more severe for the SLIDING systems without restoring force (i.e. pure-friction) in comparison to the systems with restoring force.

This article investigates the problem of simultaneous attitude and vibration control of a flexible spacecraft to perform high precision attitude maneuvers and reduce vibrations caused by the flexible panel excitations in the presence of external disturbances, system uncertainties, and actuator faults. Adaptive integral SLIDING mode control is used in conjunction with an attitude actuator fault iterative learning observer (based on SLIDING mode) to develop an active fault tolerant algorithm considering rigid-flexible body dynamic interactions. The discontinuous structure of fault-tolerant control led to discontinuous commands in the control signal, resulting in chattering. This issue was resolved by introducing an adaptive rule for the SLIDING surface. Furthermore, the utilization of the sign function in the iterative learning observer for estimating actuator faults has not only enhanced its robustness to external disturbances through a straightforward design, but has also led to a decrease in computing workload. The strain rate feedback control algorithm has been employed with the use of piezoelectric sensor/actuator patches to minimize residual vibrations caused by rigid-flexible body dynamic interactions and the effect of attitude actuator faults. Lyapunov's law ensures finite-time overall system stability even with fully coupled rigid-flexible nonlinear dynamics. Numerical simulations demonstrate the performance and advantages of the proposed system compared to other conventional approaches.

This paper considers the work entitled “ Dynamic SLIDING Mode Control Design for Nonlinear Systems Using SLIDING Mode Observer” that is published in Tabriz Journal of Electrical Engineering where the authors try to design a SLIDING mode control design with SLIDING mode observer for a class of nonlinear systems. In this paper, we first give a brief overview of the proposed approach of aforementioned paper to the observer design. For the convergence of the estimation error, there is a proposition that we will discuss the validity of its proof. Finally, with a change in dynamic error equations of observer, its stability is proven.