• Journal of Surface Science and Engineering
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• v.49 no.5
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• pp.423-430
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• 2016

In this study, we investigated the corrosion damage characteristics of steel for offshore wind turbine tower substructure using an accelerated electrochemical test. The galvanostatic corrosion test method was employed with a conventional 3 electrode cell in natural sea water, and the steel specimen was served as a working electrode to induce corrosion in an accelerated manner. Surface and cross-sectional image of the damaged area were obtained by optical microscope and scanning electron microscope. The weight of the specimens was measured to determine the gravimetric change before and after corrosion test. The result revealed that the steel tended to suffer uniform corrosion rather than localized corrosion due to active dissolution reaction under the constant current regime. With increasing galvanostatic current density, the damage depth and surface roughness of surface was increased, showing approximately 25 times difference in damage depth between the lowest current density ($1mA/cm^2$) and the highest current density ($200mA/cm^2$). The gravimetric observation showed that the weight loss was proportionally increased with increment of current density that has 75 times different according by experimental conditions. Consequently, uniform corrosion of the steel specimen was conveniently induced by the electrochemically accelerated corrosion technique, and it was possible to control the extent of the corrosion damage by varying the current density.

• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2396-2406
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• 2021

The Pacific Earthquake Engineering Research (PEER) Center has been developing a performance-based earthquake engineering (PBEE) methodology, which is based on explicit determination of performance, e.g., monetary losses, in a probabilistic manner where uncertainties in earthquake ground motion, structural response, damage estimation, and losses are explicitly considered. To carry out the PEER PBEE procedure for a component of the nuclear power plant (NPP) such as the cable tray system, hazard curve and spectra were defined for two hazard levels of the ground motions, namely, operation basis earthquake, and safe shutdown earthquake. Accordingly, two sets of spectral compatible ground motions were selected for dynamic analysis of the cable tray system. In general, the PBEE analysis of the cable tray in NPP was introduced where the resulting floor motions from the time history analysis (THA) of the NPP structure should be used as the input motion to the cable tray. However, for simplicity, a finite element model of the cable tray was developed for THA under the effect of the selected ground motions. Based on the structural analysis results, fragility curves were generated in terms of specific engineering demand parameters. Loss analysis was performed considering monetary losses corresponding to the predefined damage states. Then, overall losses were evaluated for different damage groups using the PEER PBEE methodology.

• Journal of Surface Science and Engineering
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• v.52 no.1
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• pp.23-29
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• 2019

Electrolytic corrosion of the ship's hull can be occurred due to stray current during welding work using shore power and electrical leakage using shore power supply. The electrolytic corrosion characteristics were investigated for Al5083-H321 through potentiodynamic polarization and galvanostatic corrosion test in natural seawater. Experiments of electrolytic corrosion were tested at various current densities ranging from $0.01mA/cm^2$ to $10mA/cm^2$ for 30 minutes, and at various applied time ranging from 60 to 240 minutes. Evaluation of electrolytic corrosion was carried out by Tafel extrapolation, weight loss, surface analysis after the experiment. In the electrolytic corrosion characteristics of Al5083-H321 as the current density increased, the surface damage tended to proportionally increase. In the current density of $0.01mA/cm^2$ for a applied long time, the damage tended to grow on the surface. In the case of $10mA/cm^2$ current density for a applied long time, the damage progressed to the depth direction of the surface, and the amount of weight loss per hour increased to 4 mg/hr.

• Journal of Applied Biological Chemistry
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• v.43 no.3
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• pp.161-164
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• 2000

The effects of storage temperature and high relative humidity (RH) on the weight loss, color change, and microbial activity of a mushroom ('Sylvan' hybrid white) were investigated. The experiment was performed at three temperature (5, 10 and $15^{\circ}C$) and four different relative humidity levels (91, 94, 97 and 99%). The weight loss of the tested samples had a highly correlated linear relationship with storage time at each RH level during storage. Both the storage temperature and RH levels in the experiment had signigicant effects (p<0.05) on the weight-loss rate of the tested samples. The loss whiteness of mushrooms was not significantly affected (p>0.05) by RH ranges at the same temperature. No visible damage was caused by either bacteria or fungi in all samples during storage.

• Journal of Biosystems Engineering
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• v.6 no.1
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• pp.48-59
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• 1981

The major limiting factor on the determination of combine capacity is the frequent occurence of clogging over the some parts of machine when the crop is wet in the case of Japanese self-feeding type combine. And in the case of American conventional combine having big separating parts, the great grain loss and damage occur when the machine is used for rice harvesting. This experiment was carried out to develop the new type threshing and separating equipment. Proto-type thresher which consist of a conical threshing drum and a conical separating sieve rotating around the threshing cone was constructed and tested. In the case of 800 rpm of threshing cone speed, average threshing loss was below 1 percent, separating loss was about 1 percent, grain damage was about 0.4 percent, and average total power required was about 2.6 PS. This design has some problems such as higher power required or wrapping problems under the conditions of feeding long damp straw. But, compared with the conventional combine or thresher, this machine certainly has some potentials for this approach to combine development. The crop feed rate must be increased through improvement of the feeding portion of the threshing cone. And it is required to investigate further about some parameters causing wrapping phenomena.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1598-1611
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• 2016

In some special occasions with strict size requirements, such as mine hoists, improving the design accuracy of the forced-air cooling systems of NPC three-level inverters is a key technology for improving the power density and decreasing the volume. First, a fast power-loss calculation method was brought. Its calculation principle introduced in detail, and the computation formulas were deduced. Secondly, the average and dynamic power losses of a 1MW mine hoist acting as the research target were analyzed, and a forced-air cooling system model based on a series of theoretical analyses was designed with the average power loss as a heat source. The simulation analyses proves the accuracy and effectiveness of this cooling system during the unit lifting period. Finally, according to an analysis of the periodic working condition, the maximum power-loss range of a NPC three-level inverter under multi cycle operation was obtained and its dynamic power loss was taken into the optimized cooling system model as a heat source to solve the power device damage caused by instantaneous heat accumulation. The effectiveness and feasibility of the optimization design based on the dynamic power loss calculation of the maximum power-loss range was proved by simulation and experimental results.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.53
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• pp.31-48
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• 2012

If see CISG's passing of risk and altered regulations first, when sales contract accompanies transport of goods and seller does not have duty to deliver goods at particular place, when deliver to the first carter to send to purchaser according to sales contract risk passes to purchaser, and when there is duty that seller must deliver goods to carter at specification place, when goods are delivered to carter at same place, risk does not pass to purchaser. Second, risk about transporting goods passes to purchaser at signing a contract. But, when there is special assessment, risk passes to purchaser when goods are delivered to carter who publish document that embody contract of carriage. Nevertheless, it is loss if seller did not notify this truth to occasion purchaser who could knew loss or damage of goods or know justly at sales contract conclusion defamation danger seller of be burdensome. Third, seller has responsibility about damage or loss as long as hide in own artificiality or forbearance after risk passes to purchaser. Regulation about risk in Incoterms 2010 was separated into 11 condition, and move time of risk differs in angle condition. It is appeared that the substance handles relatively comprehensively because compare in Incoterms 2010 although it is because it becomes if it examines regulation about deliver and passing of risk of goods setting in CISG relatively concise. Also, segments that can become posibility of analysis controversy exist.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.84-84
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• 2002

Abstract To study the status of oxidative DNA damage in Helicobacter pylori infection in more details, gene-specific oxidative DNA damage was investigated by examining oxidative DNA damage to individual genes. This was done by determining the loss of PCR product of a targeted gene before and after gastric mucosal DNA was treated with 8-hydroxyguanine glycosylase, which cleaves DNA at the 8-hydroxyguanine residues.(omitted)

• Korea Trade Review
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• v.45 no.4
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• pp.125-136
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• 2020

Freight charges are one of the major clauses in the voyage charter. However, in case of unexpected delays at loading and discharging ports, the owner of the ship would not be willing to cover the various costs he should bear by paying the freight receives from the charterer. Therefore, the shipowner, whose time and the ship would be both considered to be an expense, would try to reduce the laytime as least as possible when signing the charter party and to receive compensation such as demurrage and damage for detention from the charterer, just waiting for the agreed laytime to pass. In this study, we review the differences between demurrage and damage for detention and examine the acknowledgeable circumstances through the actual cases. Since the shipowner and the charterer do not often agree on the damage for detention from the respective contract, it is necessary to examine each. Besides, the shipowner and the charterer must acquaint the damage for detention and specify in a contract, to compensate for the actual loss of the shipowner.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.471-478
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• 2000

Ground movements are inevitably caused by tunnel construction in soft ground. In the design and construction of tunnels in urban areas, the potential effects of buried pipelines by ground movements are one of the important design cosiderations. Generally, the most common modes of failure of buried pipelines due to ground movements are tensile fracture of main pipelines, rotation angle and pull-out displacement at joints. In the parametric study, a wide range of conditions were considered, including tunnel diameter(D), tunnel depth(Z$\sub$0/), volume loss(V$\sub$ι/) and inflection point(i). Based on this results, design charts, which are applicable to assess potential damage of buried pipelines associated ground movements due to tunnelling, are developed.