• Journal of Pharmacopuncture
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• v.18 no.2
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• pp.86-87
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• 2015

Objectives: Condurango is widely used in various systems of complementary and alternative medicine (CAM) against oesophageal and stomach ailments including certain types of cancer. However, until now no systematic study has been conducted to verify its efficacy and dose with proper experimental support. Therefore, we examined if ethanolic extract of Condurango could ameliorate benzo[a]pyrene (BaP)-induced lung cancer in rats in vivo to validate its use as a traditional medicine. Methods: After one month of scheduled BaP feeding (50 mg/kg body-weight), lung cancer developed after four months. BaP-intoxicated rats were then treated with Condurango (0.06 mL) twice daily starting at the end of the four months for an additional one, two and three months, respectively. Effects of Condurango were evaluated by analyzing lung histology, reactive oxygen species (ROS) and antioxidant biomarkers, DNA-fragmentation, RT-PCR (Reverese Transcriptase-Polymerase Chain Reaction), ELISA (Enzyme linked immunosorbent assay) and western blot of several apoptotic signalling markers and comparing the results against those obtained for controls. Results: A histological study revealed gradual progress in lung tissue-repair activity in Condurango-fed cancer-bearing rats, showing gradual tissue recovery after three months of drug administration. Condurango has the capacity to generate ROS, which may contribute to a reduction in anti-oxidative activity and to an induction of oxidative stress-mediated cancer-cell death. Condurango-activated pro-apoptotic genes (Bax, caspase-3, caspase-9, p53, cytochrome-c, apaf-1, ICAD and PARP) and down-regulated antiapoptotic-Bcl-2 expression were noted both at mRNA and protein levels. Studies on caspase-3 activation and PARP cleavage by western blot analysis revealed that Condurango induced apoptosis through a caspase-3-dependent pathway. Conclusions: The anticancer efficacy of an ethanolic extract of Condurango for treating BaP-induced lung cancer in rats lends support for its use in various traditional systems of medicine.

• Journal of the Korean GEO-environmental Society
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• v.23 no.5
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• pp.25-32
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• 2022

As recently, there have been two earthquakes with a magnitude of 5.0 or greater in Korea and the number of smaller earthquakes has increased, a lot of research and interest in earthquake-resistant design are increasing. Especially, the Pohang earthquake has also raised interest in earthquake-resistant design of port facilities. In this study, experiments and analysis were conducted on the dynamic behavior of upright and inclined breakwaters during earthquakes among port structures through the 1g shaking table test. To this end, three seismic waves were applied to the model to which the similarity law (scale effect) was applied: long period (Hachinohe), short period (Ofunato) and artificial seismic waves. The acceleration and displacement of the upright and inclined breakwaters were analyzed according to whether the DCM method was reinforced during earthquakes based on the results of shaking table test. As the result, the dynamic behavior of the upright and inclined breakwater shows a tendency to suppress the amplification of acceleration as bearing capacity and rigidity increase when DCM method is reinforced.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2411-2425
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• 2013

In the design of pile foundation on the rock layer in the stratified structure with sedimentary and rock layers, the structural analysis of the stratified rock layer is required to determine the failure modes (flexural failure, punching shear failure or end bearing failure) and the bearing capacity of the rock layer. However, the existing usable Elastic Plate Analysis Method (EPAM) suggested by ACI committee 436 and Korean Code Requirements for Structural Foundation Design is very complex, and engineers have many difficulties in using it. Therefore, in this research, we proposed the relatively simple Circular Foundation Analysis Method (CFAM) with the concept and the equation of the equivalent effective width (radius) instead of the complex EPM, and the related equations of bending moment and shear force to be equal to the analysis results of EPAM. As a result, the proposed CFAM using the equivalent effective width (radius) is simple and convenient to use, and the analysis results of it are very good in their accuracies comparing those of EPAM and Finite Element Method.

• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.195-205
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• 2015

The rahmen bridge is well known common type of bridge in which all members are connected rigidly. The rahmen bridge is built for several situations because it has many advantages such as no need of bridge bearing system, easy of maintenance, reduction of the cross-sectional area of superstructure, and relatively low construction cost compared with other bridge types. Recently, to lengthen the span of rahmen bridge system, steel-concrete composite beam is used for superstructure of rahmen bridge instead of normal concrete girder with slab. However, member forces are increased because of extension of span length of superstructure and substructure is designed and constructed inefficiently when steel-concrete composite rahmen bridge is designed. In this study, new-type steel-concrete composite bridge is suggested. New-type steel-concrete composite rahmen bridge is adopted hinge connection between abutment and foundation for the reduction of the bending momemt at the foundation. In this study, we present the results of experiment conducted to estimate the load carrying capacity of new-type steel-concrete composite rahmen bridge and the structural characteristics of hinge connection.

• Journal of the Korean Wood Science and Technology
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• v.35 no.3
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• pp.10-21
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• 2007

It is necessary to study about moment performance of glulam-dowel connections which had been applied rotation. To analyze and predict the moment performance, angled to grain load was replaced with parallel to grain load and perpendicular to grain load. The dowel bending strength and dowel bearing strength were tested. And tensile strength test for connections of two different end distances was performed. Specimens of rotation test were composed with different drift pin numbers and drift pin arrangement. Connection deformation was occurred by plastic behavior of drift pin after yield when tensile load applied at connection. And the absorbing drift pin deflection by end distance continued the connection deformation. When rotation applied at connection that 2 drift pins were arranged parallel to grain (b2h), it showed similar performance with tensile perpendicular to grain. And connection that 2 drift pins were arranged perpendicular to grain (b2v) showed similar performance with tensile parallel to grain. Connection capacity that 4 drift pins were arranged rectangular (b4) showed 1.7 times as strong as connection that 2 drift pins were arranged parallel to grain (b2h). These results agreed predicted values and it is available that rotation replaced with tensile load.

• Journal of Korean Society of Steel Construction
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• v.21 no.1
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• pp.63-70
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• 2009

Failure modes result in fracture or tearing, which may cause deterioration of resistance and reduction of inelastic deformation capacity. The potential failure modes for Special Concentrically Braced Frames (SCBFs) include fracture or tearing of the brace, net section fracture of the brace or gusset plate, fracture of the gusset plate welds, shear fracture of the bolts, block shear, excessive bolt bearing deformation, and buckling of the gusset plate. HSS tubular braces are commonly used in SCBFs, and net section fracture of the tubular brace may also occur through the brace net section at the end of the slot cut into the tube to slip over the gusset plate. This failure mode is categorized as a tension failure mode, and may cause dramatic loss of resistance and brittle behavior. Net section reinforcement is required according to AISC design specifications (AISC 2001). In this paper, the need to reinforce the net section area was discussed. Initially, the results of the net section fracture tests done by the University of California in Berkeley were presented with the modeling of these tests using FE models. To investigate the possibility of net section fracture in an actual frame, the slot end hole model was adapted to the frame FE model, and alternate near-fault histories were applied with tension-dominated cycles, since previous analyses showed that loading history was the most critical factor in net section fracture. The need for this reinforcement (cover plate) and the tension-dominated near-fault history were investigated.

• Journal of Biosystems Engineering
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• v.38 no.4
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• pp.240-247
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• 2013

Purpose: This study was conducted to develop a rubber-crawler type vehicle as a traveling device for harvesting water-dropwort cultivated in water contained paddy rice field in winter season. Methods: A commercial rubber-crawler type vehicle was used to investigate application of rubber crawler to the paddy rice field as preliminary test. As the result of the preliminary test, a both prototype traveling device with rubber crawlers for a water-dropwort harvest was designed with inclination of $45^{\circ}$ at the front-end and rear-end of crawler under the basic water depth of 0.6 m in the paddy rice field. The device was fabricated and attached to the experimental harvesting test devices on the front of the prototype vehicle. The size of the prototype crawler vehicle with a harvesting part is $2,800{\times}1,460{\times}1,040 $ (mm) ($L{\times}W{\times}H$) with weight of 9.21 kN (maximum). Sizes of the crawler of prototype vehicle are ground contact length of 900 mm, width of 180 mm, height of 1,070 mm and distance between center to center of crawlers of 720 mm. The side-overturn angle of the prototype was $26.4^{\circ}$. Results: Driving performance of the prototype vehicle in water contained paddy field were good at both forward and reverse (backward) directions as weights were applied. The drawbar pull and the maximum sinking depth of the prototype vehicle were 3.5 kN and 0.13 m respectively at water depth of 0.5 m, when the weight and bearing capacity of the prototype rubber crawler in the paddy field were 8.51 kN and 26.3 $kN/m^2$, respectively. Conclusions: Results of the driving test performance of the prototype crawler in paddy rice field at the water depth of 0.5 m were satisfactory. The prototype had enough drawbar pull and driving ability in the deep water contained paddy field.

• Journal of the Korean Geotechnical Society
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• v.38 no.4
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• pp.21-32
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• 2022

Steel pile foundations are widely used for offshore constructions due to their high bearing capacity and efficiency. Typically, offshore structures that have reached the end of their design life are required to be demolished. However, pile foundations are often left on site due to technical and economic limitations. The pile left on the site not only pollutes the environment, but can also cause obstacles for the construction of new structures. Therefore, research is required to completely eliminate these foundations at the site. In this study, a new type of double-wall pile foundation that can drastically reduce the pull-out load was conceptually proposed, and a series of model tests were performed to validate the performance of the double-wall pile foundation. The installation and extraction of the double-wall pile were simulated in dry sand in the model test, and the measured up-lift load was compared to that of the conventional pile. According to the result, the maximum up-lift load induced by the decommissioning of the double-wall pile was reduced by 45% when compared to the traditional pile in dense sand. This study verified the mechanism for reducing the up-lift load of the double-wall foundation and confirmed the possibility of completely decommissioning a pile that has reached the end of its nominal service life.

• Geotechnical Engineering
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• v.5 no.1
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• pp.7-18
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• 1989

In pile load tests on end bearing piles, generally, it is not possible to continue loading to the ultimate load. Thus, the concept of yield load has been introduced for determining design loads Iron the pile load test records. The conventional rules to determine the yield load were not available for evaluation on pile load test records obtained in 6 fields nearby westers 8r Southern Coasts in Korea. A new rule 9.as presented to determine easily the yield load, based on investigations on the pile load test records. The yield load of piles is determined at the infiection point on semi-logarithmic coordinates (P-logS), in which load is plotted in normal scale and settlement is plotted in logarithmic scale. This method may not only save much costs and times but also present safe luorking circumstances for pile load tests in field. It was found that the yield load represented the elastic limit of the pile load-settlement behalf.iota. The ultimate load, which is given at 25.4mm settlement on pile head, was 1.5 times of the yield load. The allowable long-term and short-term load capacities were, respectively, 50% and 75% of the yield load. The safety factors to get the allowable pile capacity were obtained as 2.0~4.0 for the equations to predict the static pile capacity.

• Journal of Korean Society of Steel Construction
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• v.21 no.4
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• pp.421-432
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• 2009

In this study, push-out and static loading tests were conducted to evaluate the behavioral characteristics of composite beams with a perfobond rib shear connector. The shear capacity of the perfobond rib was found to be proportional to its concrete strength, which is in turn affected by the increase in the concrete end-bearing strength and concrete dowel action to resist the shear force. The relative slips of the push-out specimen, however, which was used to assess the ductility of the shear connector, increased to some extent, but it no longer increased when it reached the critical concrete strength because of the flexibility of the transverse rebar in the rib hole. The static-loading-test results revealed a crack on the concrete slab in the composite beam with a perfobond rib on the side of the rib hole and transverse rebar for the applied moment and shear force to the rib hole, depending on the static loading. The shear resistance characteristics of the perfobond rib shear connector were found to resist the shear force from the relative slip on the interface of the composite beam. Thus, the sectional effect of the shear connector to the composite beam with a perfobond rib should be considered when designing the composite beam because the behavior of the composite beam can change owing to the shear connector.