• Computers and Concrete
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• v.14 no.3
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• pp.263-277
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• 2014

This study investigated four electric field configurations of two-dimensional accelerate lithium migration technique (ALMT), including line-to-line, plane-to-line, contour-to-line and plane-to-plane, and analyzed the ion migration behavior and efficiency. It was found that the free ion distribution diagram and voltage distribution diagram were similar, and ions migrated in the power line direction. The electrode modules were used for the mortar specimen with w/c ratio of 0.5. The effectively processed areas accounted for 14.1%, 39.0%, 49.4% and 51.4% of total area respectively on Day 28. Larger electrode area was more advantageous to ion migration. In addition, it was proved that the two-dimensional electric field could be divided into different equifield line active regions, and regarded as affected by one-dimensional electric field, and the ion migration results in various equifield line active regions were predicted by using the duration analysis method based on the theoretical model of ion migration obtained from one-dimensional test.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.203-211
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• 1998

It is well recognized recently that acoustic emission, which is an elastic wave generated from rapid release of elastic energy in steressed solids, is very useful tool for on-line monitoring of microscopic behavior of deformation of material. In this study, three point bend test was performed to evaluate the microscopic damage progress during the loading and failure mechanism of mortar beam by monitoring the characteristic of AE signal. The relationship between AE characteristic and microscopic failure mechanism is discussed. In addition 2 dimensional AE source location based on triangular method was also done to monitor the intiation and propagation of micro crack around notch tip of mortar beam. It was shown that AE source location was very effective to predict the growth behavior of micro crack in mortar beam specimen.

• The Journal of Information Systems
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• v.14 no.1
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• pp.251-275
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• 2005

The advantages of implementing a virtual channel can be derived from the notion of the 'death of distance' that would result from electronic commerce. According to this view, the internet was going to make distance irrelevant, in that firms would no longer need to establish a physical presence in a geographical location in order to do business there. However, on-line firms selling physical products could take advantages of presence in the related off-line(brick and mortar) industrial area. This paper developed a conceptual framework that highlights the various types of synergies by location on-line businesses in the related off-line industrial area. Using data from 96 on-line ventures selling physical products, factor analysis was used to figuring out six synergies including improved customer trust, value-added service, cost savings, personnel and organizational efficiency, sharing products and customer information, relationship with suppliers, and relationship with local government. The six empirically derived critical synergy factors were then used to examine how they improve performance of the on-line ventures measured by Balanced Scorecard(BSC). According to lthe results, we concluded that the on-line firms selling physical products can take advantages of presence in the related off-line industrial area.

• Science of Emotion and Sensibility
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• v.14 no.4
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• pp.663-674
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• 2011

Two experiments were conducted to examine how additional dotted lines and peripheral stimulus to the caf$\grave{e}$ wall illusion affect on the degree of perceived tilt (amount of illusion) and confidency of illusionary perception. The experiment 1 tested the effects of adding mortar (solid line) and bright contrast dotted lines to the borderline of 3 layers of blocks, which are consisted of black and white blocks. On the experiment 2, effects of adding peripheral stimulus on caf$\grave{e}$ wall illusion were tested. The results of experiment 1 showed that adding dotted line on the borderline mortar between blocks has additive effects on confidency of illusory perception. However, no effect on perceived amount of illusion was noted. On the other hand according to the results of experiment 2, adding blocks did increase amount, but not confidency of illusory perception. These results imply that the perception of caf$\grave{e}$ wall illusion is related with response of orientation selective neurons.

• Journal of the Korea Concrete Institute
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• v.12 no.3
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• pp.67-75
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• 2000

It was well recognized that the damages associated mainly with the aging of civil infrastructures were one of very serious problems for assurance of safety and reliability. Recently carbon fiber sheet(CFS) has been widely used for reinforcement and rehabilitation of damaged concrete beam. However, the fundamental mechanism of load transfer and its load-resistant for carbon fiber sheet reinforced concrete are not fully understood. In this study, three point bending test has been carried out to understand the damage progress and the micro-failure mechanism of CFS reinforced mortars. For this purpose, four different types of specimens are used, that is, mortar, steel bar reinforced mortar, CFS reinforced mortar, and steel bar and CFS reinforced morter. Acoustic Emission(AE) technique was used to evaluate the characteristics of damage progress and the failure mechanism of specimens. in addition, two-dimensional AE source location was also performed to monitor crack initiation and propagation processes for these specimens.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.781-786
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• 2003

This study has focused on the possibility for recycling tailings from the Sangdong tungsten mine as admixture for concrete. The XRD(X-ray diffraction analysis) and PSA(Particle size analysis) were performed to find mineralogical characteristics. As a result of XRD analysis, the tailings were composed of quartz, feldspars and muscovites, and C-S-H and quartz were found in cement mortar. As a result of KSLT for cement mortar mixed with tailings, most of heavy metals were determined as below the guide line for waste material. In addition, the setting time and compressive strength of cement mortar mixed with tailings were investigated. It was indicated that the initial and final set were retarded according to increasing replacement. The compressive strength of mortar was decreased with increasing replacement.

• Journal of the Korean Society for Railway
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• v.9 no.2 s.33
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• pp.222-229
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• 2006

Recently, the development of the paved track is required as a low-maintenance of conventional line. The main reason is that the line capacity and bearing of track are increased progressively. The important factors of paved track are stability and applicability. To be based on this subject, Cement Mortar Pouring(CMP) paved track is developed. CMP paved track is a kind of ballast reinforced track using the prepacked concrete technique. The most important thing to design the paved track is to optimize the track structure considering various conditions. Because construction environment is very limited, cost is expensive and it has very complicated behavior. On this paper, structural characteristics of the paved track are investigated using the 3D finite element analysis to verify the optimized structure of the CMP track.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.836-841
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• 2004

Recently, the development of the paved track is required as a Low-maintenance of conventional line. The main reason is that the line capacity and bearing of track are increased progressively. The most important factor of paved track is stability and applicability. To be based on this subject, Cement Mortar Pouring(CMP) paved track is developed. CMP paved track is a kind of ballast reinforced track using the pre packed concrete technique. The most important to design is characteristics of the structure. CMP slab's thickness is less than the conventional slab track and pouring layer is attached tie and roadbed directly. On this paper, to verify the basic structure of the CMP track, characteristics of the structure is investigated pouring layer, tie and interaction of the each layer using the 3D finite elment analysis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.2
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• pp.135-145
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• 1988

This study deals with the prediction of crack propagation in concrete mortar subjected to static and dynamic load. Total 54 CLWL-DCB(Crack-line-loaded-double-cantilever beam) concrete mortar specimens were tested to measure crack growth using ASTM 561-80. Main variables were sand to cement ratio and water to cement ratio. The resulting load(P)-COD(Crack Opening Displacement; $2V_1$) curves and COD-CTOD (Crack Tip Opening Displacement; $2V_2$) curves were analyzed to calculate effective crack length and physical crack length by way of ASTM 561-80 proposed. Replica crack length were also obtained directly during the test. The differences in crack propagation between under static load and under dynamic load were investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.169-172
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• 2000

In this paper applicabilities of coolant wastes are an admixture, which are produced from cooling line of the cars and industrial engines, to concrete under cold climate are investigated. According to the test results, as the contents f coolant wastes increase, setting time of cement mortar is shown to be delayed. However, when coolants wastes are overadded, it appears to be fast. In case of compressive strength, It tends to decline as the contents of coolant waste increase. Under low curing temperature, compressive strength of cement mortar containing coolant wasted with the increase of the contents of coolants wastes.