response modification factor (r factor) is one of the seismic design parameters to be considered in evaluating the performance of buildings during strong motions. this paper has tried to evaluate the response modification factor of concrete coupled shear wall structures with various length/depth ratios of spandrel beams. the effect of diagonal reinforcement of spandrel beam was also evaluated o...

Testing using standard function generators for frequency response, pulse response is common. Oftentimes, certain nonlinear systems such as testing of saturable reactors, semiconductors of the p-n-p-n type as well as testing of avalanche conditions in power transistors need sharp rise and slow fall signals To this end, a PC based function generator where any kind of signal pattern such as the ab...

Nonlinear bistable systems have been shown to provide improved efficiency for harvesting energy from random and broadband vibration sources. This article explores the distinct frequency response in the broadened spectrum of a particular nonlinear energy harvester, a piezoelectric cantilever with magnetic coupling. The cantilever response evolves dynamically with frequency around the main cantil...

The leading nonlinear stress response in a periodically strained concentrated colloidal dispersion is studied experimentally and by theory. A thermosensitive microgel dispersion serves as well-characterized glass-forming model, where the stress response at the first higher harmonic frequency (3ω for strain at frequency ω) is investigated in the limit of small amplitude. The intrinsic nonlineari...

This paper presents a spectral analysis of the response of a fluid containing bubbles to the motions of a wall oscillating normal to itself. First, a Fourier analysis of the Rayleigh-Plesset equation is used to obtain an approximate solution for the nonlinear effects in the oscillation of a single bubble in an infinite fluid. This is used in the approximate solution of the oscillating wall prob...

This study presents observations of nonlinear soil behavior evidence at several KiK-net sites. First, we compare the site responses performed with 1) the recordings from the aftershocks and 2) the recordings from the main event of the 2011 Tohoku earthquake at four sites. Then, to understand the influence of soil parameters on nonlinear effects, we extend the results to the whole network. We co...

We present an experimental and theoretical investigation into the coupling of C-O stretch vibrations of CO molecules adsorbed on Ru~001!. We employ surface infrared-visible ~IR-VIS! ~IV! and infrared-infraredvisible ~IR-IR-VIS! ~IIV! sum-frequency generation ~SFG! ~IV-SFG and IIV-SFG, respectively! to investigate the effects of the intermolecular coupling through the nonlinear optical response ...

We demonstrate nonlinear excitation of surface plasmons on a gold film by optical four-wave mixing. Two excitation beams of frequencies omega(1) and omega(2) are used in a modified Kretschmann configuration to induce a nonlinear polarization at a frequency of omega(4wm)=2omega(1)-omega(2), which gives rise to surface plasmon excitation at a frequency of omega(4wm). We observe a characteristic p...

This paper presents a nonlinear model of a clamped-clamped microbeam actuated by an electrostatic load with stretching and thermoelastic effects. The frequency of free vibration is calculated by discretization based on the Differential Quadrature (DQ) Method. The frequency is a complex value due to the thermoelastic effect that dissipates energy. By separating the real and imaginary parts of fr...

This paper describes a new design for direct sliding mode method with a high switching frequency using the PD-PI type sliding surface applied to a negative output Luo converter worked in continuous current mode for applications required constant power source such as aerospace applications, medical equipment and etc. Because of the output power and line changes, the converter model is also nonli...