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71.
The complexity of determining strain associated with shear modulus and damping ratio in torsional tests has been resolved by means of several approaches. The stress integration approach is adequate when generating the plots of equivalent radius ratio versus strain more effectively over any range of strains in resonant column and torsional shear (RC/TS) tests. The stress integration approach was applied for hyperbolic, modified hyperbolic, and Ramberg–Osgood models in evaluating damping ratio. This study showed that using a single value of equivalent radius ratio in evaluating damping ratio is not appropriate. The combined hysteretic‐nonviscous damping model was developed and employed to consider the increased damping behavior at small strains using the stress integration approach. The results suggest that adding viscous behavior has no significant effect strain calculations in RC/TS testing. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
72.
Koterayama W. Yamaguchi S. Yokobiki T. Jong-Hwan Yoon Hase H. 《Oceanic Engineering, IEEE Journal of》2000,25(1):130-138
A research project to develop observation systems for heat, momentum, and material circulation in the ocean and atmosphere was carried out from 1992 to 1997. A pitch, roll, and depth controllable towed vehicle called “Flying Fish” was developed which houses an acoustic Doppler current profiler, CO2 analyzer, and sensors for measuring temperature, salinity, dissolved oxygen, pH, turbidity, and chlorophyll. The length of the vehicle is 3.84 m, the breadth is 2.26 m, the height is 1.4 m, the weight in air is 1400 kg, and the weight in water is roughly 0 kg. Flying Fish enables us to obtain space-continuous data of physical and chemical properties efficiently in the upper mixed layer of the ocean, From 1994 to 1997, the vehicle was used for observations in the northern, southern, and central parts of the Japan Sea in a collaborative study by Japan, Korea, and Russia. Examples of data obtained are shown in this paper and the results of current velocities are compared with those taken by other observation systems 相似文献
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74.
Myoung?Hak?Oh Ju?Hyung?Lee Gil?Lim?Yoon Junboum?ParkEmail author 《Environmental Geology》2003,45(2):181-189
The grid-net electrical conductivity measurement system for detecting exact locations of landfill leachate intrusion in the subsurface was developed in this study. Laboratory and pilot-scale field model tests were performed to evaluate the direct application of a grid-net electrical conductivity measurement system for the detection of landfill leachate. A significant increase in electrical conductivity of soil was observed by adding landfill leachate. This can be explained as an increase in electrical conductivity of pore fluid due to an increase in leachate constituents as charge carriers. In pilot-scale field model tests, leachate intrusion locations were accurately identified at the initial stage of landfill leachate release by the grid-net electrical conductivity measurement system. The electrical conductivity of the subsurface before leachate injection lay within a small range of 24.8–43.0 S/cm. The electrical conductivity values in detected points were approximately ten times more than the conductivity values of the subsurface without landfill leachate intrusion. The results in this study indicate that the grid-net electrical conductivity measurement method has a possible application for detecting locations of landfill leachate intrusion into the subsurface at the initial stage, and thus has great potential in monitoring leachate leakage at waste landfills. 相似文献
75.
Michael R. Brady Demetri P. Telionis Pavlos P. Vlachos Roe-Hoan Yoon 《International Journal of Mineral Processing》2006,80(2-4):133-143
Industrial processes involving multi-phase flows such as flotation require understanding of the relationships between bubbles, solid particles and the flow. Modern experimental tools are employed in this effort to measure with great accuracy the basic features of the motion of all three phases in turbulent flow. We employed a unique Digital Particle Image Velocimeter (DPIV) that can record with great accuracy and kHz temporal resolution, velocity vectors of all three phases, namely the fluid, the solid particles and the air bubbles. The interaction of these three phases was studied in homogeneous isotropic turbulence generated by cylindrical grids. Particles and bubbles were released into the turbulence and the motions of the three phases were monitored. The experimental results obtained in the present work were compared with the predictions of the models published in the literature. 相似文献
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The collectorless flotation process has been tested on six different chalcopyrite ores while monitoring the potentials () of the pulp. The results show that collectorless flotation is effective only under oxidizing conditions. In addition, the flotation requires that the chalcopyrite surface be relatively free of hydrophilic oxidation products, which can be accomplished by treating the ore pulp with sodium sulfide (Na2S). On the basis of these findings, methods of improving the collectorless flotation process are discussed. 相似文献
79.
Biological and Physical Attenuation of Endocrine Disruptors and Pharmaceuticals: Implications for Water Reuse 总被引:2,自引:0,他引:2
Shane A. Snyder Joseph Leising Paul Westerhoff Yeomin Yoon Heath Mash Brett Vanderford 《Ground Water Monitoring & Remediation》2004,24(2):108-118
A select group of endocrine disrupters, pharmaceuticals, and personal care products was studied to determine the degree of biological attenuation in water reuse applications. Laboratory investigations involved both batch reactors using biologically active sand and continuous flow simulated aquifer storage and recovery experiments. All laboratory experiments were conducted using Colorado River water spiked with various target compounds at concentrations between 10 and 100 ng/L. Field studies were also conducted to determine the occurrence and attenuation of target compounds in water reuse applications. Two golf courses irrigated with reuse water were studied to determine if turf applications led to contamination of nearby ground water. A waste water treatment facility that uses rapid infiltration basins seasonally was also tested to determine the degree of attenuation of detectable target compounds along a subsurface flowpath. A qualitative structural activity relationship model was applied to the target compounds to predict the general rate of aerobic biological degradation. Significant attenuation of many target compounds was observed in both laboratory and field experiments. Conversely, several compounds displayed limited removal during these studies. Field experiments were limited to detectable compounds and various nonbiological removal or concentration effects that may impact data interpretations, which are discussed in this paper. The predictive model was found to be moderately accurate within the confines of the project scope. 相似文献
80.
S. Buske S. Lüth H. Meyer R. Patzig C. Reichert S. Shapiro P. Wigger M. Yoon 《Tectonophysics》2002,350(4):93-282
In this paper, we present a compilation of modern seismic and seismological methods applied to image the subduction process in North Chile, South America. We use data from active and passive seismic experiments that were acquired within the framework of the German Collaborative Research Center SFB267 ‘Deformation Processes in the Andes’. The investigation area is located between 20° and 25°S and extends from the trench down to 100 km depth. In the depth range between the sea bottom and 15 km, we process an offshore seismic reflection profile using a recently developed velocity-model-independent stacking procedure. We find that the upper part of the subducting oceanic lithosphere in this depth range is characterized by a horst-and-graben structure. This structure supports an approximately 3 km thick coupling zone between the plates. In the depth range between 15 and 45 km, we analyse the spatial distribution of aftershocks of the Antofagasta earthquake (1995). The aftershock hypocenters are concentrated in an approximately 3 km thick layer. Finally, in the depth range between 45 and 100 km, we apply Kirchhoff prestack depth migration to the onshore ANCORP profile. A double reflection zone is observed between 45 and 60 km depth, which may represent the upper and lower boundary of the subducted oceanic crust. Over the whole range down to more than 80–90 km depth, we obtain an image of the subducting slab. At that depth, the hypocenters of local earthquakes deviate significantly in the direction perpendicular to the slab face from the reflective parts of the slab. Consequently, our results yield a complete seismic image of the downgoing plate and the associated seismic coupling zone. 相似文献