Modeling complex aquifer systems: a case study in Baton Rouge,Louisiana (USA)     

Pham  Hai V.  Tsai  Frank T.-C. 《Hydrogeology Journal》2017,25(3):601-615

Hydrogeology Journal - This study targets two challenges in groundwater model development: grid generation and model calibration for aquifer systems that are fluvial in origin. Realistic...  相似文献   

Use of LP Surface Waves for Source Characterization     

Yi-Ben Tsai 《Geophysical Journal International》1972,31(1-3):111-130

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Wetting weakening of tertiary sandstones—microscopic mechanism   总被引：3，自引：0，他引：3  

M. L. Lin  F. S. Jeng  L. S. Tsai  T. H. Huang 《Environmental Geology》2005,48(2):265-275

The micromechanism accounting for wetting weakening of tertiary sandstones was studied. It was found that intragranular fracture prevails for all dry sandstones. However, when the sandstone is wet, intergranular fracture occurs for Type B sandstones. Therefore, one sandstone from Type A sandstones, MS1, and another from Type B, TK, were selected to further investigate the nature of the matrix. It was found that (1) for both sandstones, the major mineral components of the matrix are illite and kaolinite except that the MS1 sandstone has more chlorite; (2) leaching of matrix induced an increase of porosity and consequently results in leaching softening; and (3) among the mineral composition, chlorite is easiest to be dissolved and leached out and induces a more significant increase of porosity, which, in turn, results in a more significant leaching softening.  相似文献   

Simplified seismic analysis of one‐way asymmetric elastic systems with supplemental damping     

Jui‐Liang Lin  Keh‐Chyuan Tsai 《地震工程与结构动力学》2007,36(6):783-800

This study investigates the effectiveness of the modal analysis using two‐degree‐of‐freedom (2DOF) modal stick to deal with the seismic analysis of one‐way asymmetric elastic systems with supplemental damping. The 2DOF modal stick possessing the non‐proportional damping property enables the modal translation and rotation to not be proportional even at elastic state. The analytical results of one‐storey and three‐storey buildings obtained by the proposed method are compared with those obtained by direct integration of the equation of motion and conventional approximate method, which neglects the off‐diagonal elements in the transformed damping matrix. It is found that the proposed simplified method, compared to conventional approximate methods, can significantly improve the accuracy of the analytical results and, at the same time, without obviously increasing computational efforts. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Adsorption kinetics of herbicide paraquat in aqueous solution onto a low-cost adsorbent, swine-manure-derived biochar     

W. -T. Tsai  H. -R. Chen 《International Journal of Environmental Science and Technology》2013,10(6):1349-1356

Biochars have received increasing attention in recent years because of their significant properties such as carbon sequestration, soil fertility, and contaminant immobilization. In this work, the adsorptive removal of paraquat (1,1′-dimethyl-4,4′-dipyridinium chloride, one of the most widely used herbicides) from aqueous solution onto the swine-manure-derived biochar has been studied at 25 °C in a batch adsorption system. The adsorption rate has been investigated under the controlled process parameters including initial pH (i.e., 4.5, 6.0, 7.5, and 9.0), paraquat concentration (i.e., 0.5, 1.0, 2.0, 4.0, and 6.0 mg/L), and biochar dosage (i.e., 0.10, 0.15, 0.20, 0.25, and 0.30 g/L). Based on the adsorption affinity between cationic paraquat and carbon-like adsorbent, a pseudo-second order model has been developed using experimental data to predict the adsorption kinetic constant and equilibrium adsorption capacity. The results showed that the adsorption process could be satisfactorily described with the reaction model and were reasonably explained by assuming an adsorption mechanism in the ion exchange process. Overall, the results from this study demonstrated that the biomass-derived char can be used as a low-cost adsorbent for the removal of environmental cationic organic pollutants from the water environment.  相似文献   

Dual compensation strategy for real‐time hybrid testing     

Pei‐Ching Chen  Keh‐Chyuan Tsai 《地震工程与结构动力学》2013,42(1):1-23

Real‐time hybrid testing is an experimental technique for evaluating the dynamic responses of structural systems under seismic loading. Servo‐hydraulic actuators, by nature, induce inevitable time delay between the command and the achieved displacements. This delay would lead to incorrect test results and even cause instability of the system; therefore, delay compensation is critical for stability and accuracy of hybrid simulations of structural dynamic response. In this paper, a dual delay compensation strategy is proposed by a combination of a phase lead compensator and a restoring force compensator. An outer‐loop feed‐forward phase lead compensator is derived by introducing the inverse model in the z domain. The adaptive law based on the gradient algorithm is used to estimate the system delay in the format of parametric model during the test. It is shown mathematically that the parameter in the delay estimator is guaranteed to converge. The restoring force compensator is adopted to improve the accuracy of experimental results especially when the structure is subjected to high frequency excitations. Finally, analytical simulations of an inelastic SDOF structure are conducted to investigate the feasibility of the proposed strategy. The accuracy of the dual compensation strategy is demonstrated through several shaking table tests. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Landslide blockage length estimation for the man-made linear structures     

Chien-Yuan Chen  Tung-Lin Tsai 《Environmental Earth Sciences》2012,67(6):1781-1787

The landslide blockage length along a man-made linear structure, the Alishan railway, is analyzed herein. The Alishan railway runs from Chiayi City to the Alishan scenic area. Numerous landslide and debris flow disasters have blocked the railway since it began operations in 1911. In this study, features of landslides are interpreted from Spot 5 images along the Alishan railway. The results show that larger landslides along the railway exhibit a power-law distribution in frequency-area analysis. The railway blockage length by landslide and its frequency can be linearized by plotting it in a log scale for a blockage length over 0.02?km. The characteristics may be attributed to the fact that the landslide magnitude for its area and volume versus frequency exhibits a power-law distribution. It may thus be possible to estimate the blockage length of linear structures (e.g., railway and expressway) by landslides using the power-law distribution.  相似文献   

A Debris-flow Simulation Model for the Evaluation of Protection Structures   总被引：3，自引：0，他引：3  

References： 《山地科学学报》2007,4(3):193-202

Debris flow is the flow of a solid-fluid mixture and in this investigation it is treated as the flow of a continuum in routing. A numerical model is proposed describing debris flow including erosion and deposition processes with suitable boundary con-ditions. The numerical model is applied to evaluate the effects of protection structures against debris flow caused by heavy rainfall on the Shen-Mu Stream of Nantou County located in central Taiwan. Simulation results indicated that the proposed model can offer useful pre-planning guidelines for engineers.  相似文献