Ki-Kwon Hong

Enhanced electrokinetic (E/K) remediation on copper contaminated soil by CFW (carbonized foods waste).

The E/K remediation method is presented to purify low permeable contaminated soils due to Cu(2+), and carbonized foods waste (CFW) was used as a permeable reactive barrier (PRB) material. For adsorption and precipitation of the Cu(2+) in the PRB during its motion, PRB was installed in a zone of rapidly changing pH values. The adsorption efficiency of CFW used as PRB material was found to be 4-8 times more efficient than that of Zeolite. Throughout the experiment, a voltage slope of 1V/cm was implemented and acetic acid was injected on the anode to increase the remediation efficiency. The electrode exchange was executed to more completely remove precipitated heavy metals in the vicinity of the cathode. The majority of Cu(2+) was adsorbed or sedimented by CFW prior to the exchange of the electrode, and the remaining quantity of precipitated Cu(2+) on the cathode had decreased with an increase in the operating time. Experiments of seven cases with different E/K operating times were performed, and the average removal ratios were 53.4-84.6%. The removal efficiencies for the majority of cases increased proportionally with an increase in the operating time. After the experiments were completed, the adsorbed Cu(2+) on CFW was 75-150 mg. This means that the role of CFW as the material in PRB for remediating heavy metals was confirmed. The cost of energies needed to remove Cu(2+), CFW, and acetic acid are estimated at US

Development of a Visual Monitoring System for Deformation Measuring of Welded Members and its Application

13.3-40/m(3).

Application of a Photogrammetric System for Monitoring Civil Engineering Structures

Recently, in the loading tests for steel members, the deformation value is measured by calculating a distance of both cross-heads. This measuring method encounters a test error due to various environmental factors, such as initial slip, etc.. Especially, in the case of welded members, the non-uniform deformation behavior in welded joints is observed because of the effect of welding residual stress and weld metal. This is mainly responsible for a test error and a loss of the reliability for used test instruments. Therefore, to improve the accuracy and the applicability of measuring system, it is necessary to employ a visual monitoring system which can accurately measure the local and overall deformation of welded members. In this paper, to accurately measure a deformation of welded members, a visual monitoring system (VMS) was developed by using three-dimensional digital photogrammetry. The VMS was applied to the loading tests of a welded member. The accuracy and the applicability of VMS was verified by comparing to the deformation value measured by a test instrument (MTS-810). The characteristics of the behavior near a welded joint were investigated by using VMS.

Geometry Design Method Considering Surcharge Load Behind Tiered Reinforced Soil Wall

Several traditional measuring apparatus are used to check the stability of civil engineering structures and maintenance of them. The measured results are applied for the deformation and stability analysis of civil engineering structures. Currently, precision and micro measuring instruments are used for stability evaluations of civil engineering structures. Furthermore, the measuring apparatus have been changed from manual systems to automatic systems. For example, total station, one of the traditional and manual measuring methods, is transferred to digital photogrammetry with high technology development. Especially, the movement of target points is able to be measured in real-time automatically because it can be obtained 3-dimensional coordinates by digital photogrammetry. The use of automatic measuring methods has been researched in several different industries (Hannah, 1989; Lee et al., 2006). The applications of digital photogrammetry are increased in various civil engineering structures (Han et al., 2001; Han & Song, 2003; Han et al., 2007, 2008). It shows that the automatic and high-tech measuring system likeVisual Monitoring System (VMS) based on digital photogrammetry is able to apply to the stability evaluations of large civil engineering structures.

Adsorption characteristics of Cu2+ and Zn2+ from aqueous solution using carbonized food waste

The construction of reinforced soil wall is a recent trend in construction work due to the economical advantage and construction efficiency. However, there have been increasing numbers of large scale collapse accidents in tiered reinforced soil wall due to inconsistent in a design manual and uncertainty in stability evaluation. The surcharge load behind the wall has effects on the stability of tiered reinforced soil wall as well as the whole ground. Therefore, this study interpreted the method of surcharge load suggested in the typical design methods (i.e., NCMA and FHWA), which are applicable in Korea. The analysis resulted in the reasonable design method and the suggested method was applied in the field case using the numerical analysis. The numerical simulations confirmed that the surcharge load behind the wall should be considered for the slip failure surface to evaluate the tiered reinforced soil wall.