Simple Equations for Predicting Maximum Displacement of Isolation Systems Using Lead Rubber Bearings

Predicting maximum displacement is an important task in designing isolation systems. An effective procedure that is widely used for this task is equivalent linear force (ELF) procedure, which is allowed by many contemporary design codes. This procedure uses very basic parameters of the isolation system as well as earthquake condition of the site to analyze for the maximum displacement. However, ELF procedures are time-consuming because they require an iteration process. This study employed an ELF procedure to generate a large database and used it to develop explicit and simple equations that can directly calculate the maximum displacement of isolation systems using lead rubber bearings. The proposed equations can confidently predict the maximum displacement calculated by the ELF procedure. In addition, the investigation showed that the first to post-yield stiffness ratio of an isolation system, which is difficult to accurately determine, has neglected effect on the maximum displacement calculated by the ELF procedure. Based on this observation, a simple equation that uses only three input parameters to predict the maximum displacement was proposed. The input parameters to the simplified equation include normalized characteristic strength and post-yield period of the isolation system, and 1-s spectral acceleration of the site. These parameters are minimum to determine an isolation system and earthquake condition. The comparison between the maximum displacement predicted by the proposed equation and the maximum displacement calculated by the ELF procedure showed that the proposed equation generates slightly conservative results for common designs, therefore is suitable for practical application

Piezoresistive effect of p-type single crystalline 3C-SiC on (111) plane

This paper presents for the first time the effect of strain on the electrical conductivity of p-type single crystalline 3C-SiC grown on a Si (111) substrate. 3C-SiC thin film was epitaxially formed on a Si (111) substrate using the low pressure chemical vapor deposition process. The piezoresistive effect of the grown film was investigated using the bending beam method. The average longitudinal gauge factor of the p-type single crystalline 3C-SiC was found to be around 11 and isotropic in the (111) plane. This gauge factor is 3 times smaller than that in a p-type 3C-SiC (100) plane. This reduction of the gauge factor was attributed to the high density of defects in the grown 3C-SiC (111) film. Nevertheless, the gauge factor of the p-type 3C-SiC (111) film is still approximately 5 times higher than that in most metals, indicating its potential for niche mechanical sensing applications

Research on wave regimes at the Cua Dai estuary, Quang Nam

In coastal area of the Cua Dai estuary - Quang Nam province, the processes of erosion-accretion strongly occur. Over this area, the ocean wave is a dynamical factor that directly affects the coastal areas causing erosion-accretion processes. This paper presents an evaluation of the ocean wave regime impacting the areas of Cua Dai estuary by using the model of MIKE21SW. The purpose of this study is to fully interprete the role of dynamical factor, ocean wave in erosion-accretion processes. The results showed a convergence of ocean waves at the estuary of Cua Dai although it is obstructed by the Cu Lao Cham island in front of the Cua Dai estuary. The northeast and north-northeast waves are mainly prevailing with the frequency of more than 60% in the year

Applications of Lp−LqL^p-L^q estimates for solutions to semi-linear σ\sigma-evolution equations with general double damping

In this paper, we would like to study the linear Cauchy problems for semi-linear $\sigma$-evolution models with mixing a parabolic like damping term corresponding to $\sigma_1 \in [0,\sigma/2)$ and a $\sigma$-evolution like damping corresponding to $\sigma_2 \in (\sigma/2,\sigma]$. The main goals are on the one hand to conclude some estimates for solutions and their derivatives in $L^q$ setting, with any $q\in [1,\infty]$, by developing the theory of modified Bessel functions effectively to control oscillating integrals appearing the solution representation formula in a competition between these two kinds of damping. On the other hand, we are going to prove the global (in time) existence of small data Sobolev solutions in the treatment of the corresponding semi-linear equations by applying $(L^{m}\cap L^{q})- L^{q}$ and $L^{q}- L^{q}$ estimates, with $q\in (1,\infty)$ and $m\in [1,q)$, from the linear models. Finally, some further generalizations will be discussed in the end of this paper.Comment: 38 page

Evaluating the Accuracy of an Equivalent Linear Model in Predicting Peak Displacement of Seismic Isolation Systems using Single Friction Pendulum Bearings

This study evaluates the accuracy of an equivalent linear model in predicting peak nonlinear time-history displacement of seismic isolation systems with single friction pendulum bearings. To perform this evaluation, dynamic response of numerical models of 120 isolation systems subjected to 390 strong earthquake ground motions, including motions with pulse and motions without pulse, was analyzed and statistically processed. The results show that the equivalent linear model can partly predict the peak displacement of its counterpart nonlinear model. However, the equivalent model can also underestimate or overestimate the peak displacement. On average sense, the equivalent linear model underestimates small peak displacement and overestimates large peak displacement. It is also observed that the relationship between linear and nonlinear peak displacements depends on ground motion types. Based on the analysis data, equations representing relationship between linear and nonlinear peak displacements at different reliable levels for different ground motion types were proposed. These equations can be used in practice

Risk Management in Viet Nam Tourism Industry under the Impact of a Two Factor Model during and after the Global Crisis

Over past few years, the global financial crisis shows certain influence on emerging financial markets including Viet nam. Therefore, this study chooses an analytical approach to give some systematic opinions on how much some certain determinants such as income tax and leverage, affect the level of market risk in listed tourism companies. First, it calculates equity and asset beta values in three (3) different scenarios of changing tax rates and changing the level of financial leverage. Second, under 3 different scenarios of changing tax rates (20%, 25% and 28%), we recognized that there is not large disperse in equity beta values, estimated at 0,753 for current leverage situation. Third, by changing tax rates in 3 scenarios (25%, 20% and 28%), we recognized both equity and asset beta mean values have positive relationship with the increasing level of tax rate. Last but not least, this paper covers some ideas and policy suggestions. 

Risk Management in Viet Nam Tourism Industry Under the Impact of a Two Factor Model During and After the Global Crisis

Over past few years, the global financial crisis shows certain influence on emerging financial markets including Viet nam. Therefore, this study chooses an analytical approach to give some systematic opinions on how much some certain determinants such as income tax and leverage, affect the level of market risk in listed tourism companies.First, it calculates equity and asset beta values in three different scenarios of changing tax rates and changing the level of financial leverage. Second, under 3 different scenarios of changing tax rates (20%, 25% and 28%), we recognized that there is not large disperse in equity beta values, estimated at 0,753 for current leverage situation.Third, by changing tax rates in 3 scenarios (25%, 20% and 28%), we recognized both equity and asset beta mean values have positive relationship with the increasing level of tax rate.Last but not least, this paper covers some ideas and policy suggestions