• Computers and Concrete
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• v.33 no.6
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• pp.643-658
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• 2024

To date, shell-solid and fibre element model analysis are the most commonly used methods to investigate the seismic performance of concrete-filled steel tube (CFST) bridge piers. However, most existing research does not consider the loss of bearing capacity caused by the fracture of the outer steel tube. To fill this knowledge gap, a refined finite element (FE) model considering the ductile damage of steel tubes and the behaviour of infilled concrete with cracks is established and verified against experimental results of unidirectional, bidirectional cyclic loading tests and pseudo-dynamic loading tests. In addition, a parametric study is conducted to investigate the seismic performance of CFST bridge piers with different concrete strength, steel strength, axial compression ratio, slenderness ratio and infilled concrete height using the proposed model. The validation shows that the proposed refined FE model can effectively simulate the residual displacement of CFST bridge piers subjected to highintensity earthquakes. The parametric analysis indicates that CFST piers hold sufficient strength reserves and sound deformation capacity and, thus, possess excellent application prospects for bridge construction in high-intensity areas.

• Corrosion Science and Technology
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• v.23 no.5
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• pp.437-448
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• 2024

This study investigated electrochemical and cavitation-erosion characteristics of three types of cast aluminum alloys in natural seawater. Electrochemical properties were evaluated by calculating corrosion potential and corrosion current density through a potentiodynamic polarization experiment in a static marine environment. Cavitation-erosion characteristics were determined by measuring surface roughness, maximum damage depth, weight loss and surface damage shape with experiment time. Indentation experiments revealed that surface hardness values of domestic products were higher than those of foreign products due to high contents of zinc, magnesium and copper. This is because zinc, magnesium and copper dissolved in the aluminum crystal lattice could transform the lattice structure. Due to increased surface hardness, domestic products showed the best cavitation-erosion resistance. However, their corrosion resistance were found to be relatively poor. This is due to formation of galvanic couples within the alloy when zinc, magnesium and copper are present in relatively high concentrations, which can accelerate corrosion.

• Journal of the Earthquake Engineering Society of Korea
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• v.5 no.3
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• pp.9-17
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• 2001

This paper focuses on the earthquake hazard delineation and physical loss estimation for lifelines and utilities. Emphasis is given to geographic information systems(GIS) and their application to pipeline networks in evaluating the spatial characteristics of earthquake effects. The paper examines the GIS databases for water supply performance obtained for the 1994 northridge. Relationships among buried lifeline damage and various seismic parameters are examined, and the parameters that are statistically most significant are identified. Using GIS data from the Northridge earthquake, the relationships among pipeline repair rate, type of pipe, diameter, and various seismic parameters are assessed.

• Smart Structures and Systems
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• v.5 no.4
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• pp.495-505
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• 2009

Bridges form crucial links in the transportation network especially in high seismic risk regions. This research aims to provide a quantitative methodology for post-earthquake performance evaluation of the bridges. The experimental portion of the research involved shake table tests of a 4-span bridge which was subjected to progressively increasing amplitudes of seismic motions recorded from the Northridge earthquake. As part of this project, a high resolution long gauge fiber optic displacement sensor was developed for post-seismic evaluation of damage in the columns of the bridge. The nonlinear finite element model was developed using Opensees program to simulate the response of the bridge and the abutments to the seismic loads. The model was modified to predict the bent displacements of the bridge commensurate with the measured bent displacements obtained from experimental analysis results. Following seismic events, the tangential stiffness matrix of the whole structure is reduced due to reduction in structural strength. The nonlinear static push over analysis using current damaged stiffness matrix provides the longitudinal and transverse ultimate capacities of the bridge. Capacity loss in the transverse and longitudinal directions following the seismic events was correlated to the maximum displacements of the deck recorded during the events.

• Nutrition Research and Practice
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• v.1 no.3
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• pp.180-183
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• 2007

Cytoprotective ability of polysaccharides isolated from different edible mushrooms was investigated on the 7-ketocholesterol-induced damaged cell line. Polysaccharide extracts from six different edible mushrooms-Flammulina velutipes, Peurotus ostreatus, Lentinus edodes, Agrocybe aegerita, Agaricus blazei, and Cordyceps militaris- were prepared by hot water extraction and alcohol precipitation. Cytoprotective ability was evaluated by measuring the viable cells of the normal embryonic liver cell line (BNL CL. 2) in the presence of 7-ketocholesterol. At $80\;{\mu}g/mL$ of 7-ketocholesterol, cytotoxicity was very high with a loss of 98% of viable cells after 20 h of incubation. With the addition of $200\;{\mu}g/mL$ of each polysaccharide isolate to the cell line containing $80\;{\mu}g/mL$ of 7-ketocholesterol, polysaccharide isolates from both Flammulina velutipes and Peurotus ostreatus could significantly inhibit the 7-ketochoelsterol-induced cytotoxicity in the cells. But other polysaccharide isolates were not effective in inhibiting cell damage caused by the oxLDL-induced cytotoxicity.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.402-409
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• 2019

When a loss of coolant accident (LOCA) occurs in a nuclear power plant, accident scenarios which can prevent core damage are defined based on break size. Current probabilistic safety assessment evaluates that core damage can be prevented under small-break LOCA (SBLOCA) and steam generator tube rupture (SGTR) with rapid cool down (RCD) strategy when all safety injection systems are unavailable. However, previous research has pointed out a limitation of RCD in terms of initiation time. Therefore, RCD success criteria estimation based on allowable coping time under a SBLOCA or SGTR when all safety injection systems are unavailable was performed based on time-line and thermal-hydraulic analyses. The time line analysis assumed a single emergency operating procedure flow, and the thermal hydraulic analysis utilized MARS-KS code with variables of break size, cooling rate, and operator allowable time. Results show while RCD is possible under SGTR, it is impossible under SBLOCA at the APR1400's current cooling rate limitation of 55 K/hr. A success criteria map for RCD under SBLOCA is suggested without cooling rate limitation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.632-638
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• 2018

Recently, damage to waterside structures, such as bridges or retaining walls, is increasing due to typhoons, flooding, aging, etc. In such cases, the damage is not limited to the structures themselves, but can include effects on a wider scale, such as the suspension of and restriction of access to the facilities, human injury, economic loss, etc. To preclude such damage, recovery methods suitable for the particular field circumstances should be applied when damage occurs. By enforcing prompt repairs, the material and human damage and losses that can occur can be minimized. Since the impact of losses caused by damage and disaster increases with the elapse of time, emergency recovery is even more important. In the emergency recovery process, appropriate repair and reinforcement is crucial. In the present study, the derivation scenarios of the emergency recovery method were applied to some field recovery cases, and their applicability was verified by comparison with the recovery methods actually used. It is expected that the results of this study will be useful for practical application, by suggesting more appropriate recovery methods.

• Journal of Families and Better Life
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• v.27 no.6
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• pp.95-109
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• 2009

This study focused on the development of a scale to measure the ability of consumers to use credit cards. The purposes of this study were to develop a tool which would be able to measure consumer knowledge, consumer skills and consumer attitudes. Data were collected from 313 credit card using consumers and were analyzed by employing a goodness of fit test, principal component analysis & confirmatory factor analysis(Amos 5.0), multiple regression. The results from this study were as follows: 1) Six factors of consumer knowledge(16-items) were identified: damage salvation; credit delinquency; personal credit information; credit provision period; credit & credit card issuance; credit delinquent striking out a record & credit rating. The total variance was 55.86%. 2) Three factors of consumer skills(17-items) were identified: credit delinquency & over-consumption; credit card management; and loss & damage salvation. The total variance was 62.90%. 3) Three factors of consumer attitudes(16-items) were identified: credit delinquency & credit; credit card issuance & use; and credit card management. The total variance was 58.75%.

• The Journal of Korean Physical Therapy
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• v.18 no.4
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• pp.1-9
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• 2006

Recently, several investigations revealed that after unilateral brain damage, movement abnormalities were exposed on the ipsilateral side as well as the upper extremity contralateral to the damaged hemisphere. Even the motor abilities had significantly recovered from ipsilateral motor deficits on not only simple sensoriomotor function, also clinical assessments since subacute stage, although could not completely returned. Such motor deficits were detected in a diversity of motor tasks depending on the interhemispheric specialization, further in clinical evaluation and a daily of activities. In the clinical features, muscular weakness, sensory loss and impaired manual dexterity were observed. In a laboratory experiment, there were increasing evidences that the kinematic processing deficits was founded in various-specific motor tasks, which ranged from simple basic element to complex tasks, such as tapping task, step-tracking, goal directional aiming task, and iso(and non-)directional interlimb coordination. In the point of view, the manifest understanding in related to ipsilateral deficits provide the clinicians with an important information for scientific management about brain injured patient's prognosis and therapeutic guidelines.

• Journal of Korean Foot and Ankle Society
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• v.12 no.2
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• pp.230-233
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• 2008

The avulsion fracture of the calcaneal tuberosity is rare injury. Usually, it occurs from indirect trauma in old patients with osteoporosis or in patients with diabetic neuropathy. Especially, the bone and joint damage occurred in active patient with severe sensory loss or arthropathy related to nerve damage regardless of the cause is referred to neuropathic arthropathy. Generally, a patient with nondisplacement or minimally displacement is treated by conservative therapy and a patient with severe displacement is treated by open reduction and internal fixation. We experienced a 33 years-old woman with diabetes mellitus who had the displaced avulsion fracture of the calcaneal tuberosity without significant trauma and did not treat. We report upon this case at the 2 years follow-up.