• Journal of Conservation Science
• /
• v.26 no.3
• /
• pp.277-294
• /
• 2010

The Seosanmaaesamjonbulsang (National Treasure No. 84) consists of light gray and coarse to mediumgrained biotite granite with partly developed pegmatite and quartz vein. The host rock is divided into dozens of rock blocks with various shape along irregular discontinuity plane. The evaluation results of discontinuity systems reveal that the host rock were exposed to instable sloping environments. Results of deterioration diagnosis show that the degree of damage has been made worse by physical weathering and surface discoloration laying stress on part that vertical and horizontal joints are massed. Generally, deterioration rate of the triad Buddha surface cover with 42.7%, however, the rate of physical weathering and surface discoloration are subdivided to 9.6% and 33.1%, respectively. Ultrasonic measurements indicate that the triad Buddha was reached highly weathered grade in general. And the rock material was weaken to show low velocity zone of 1,000m/s along irregular joint systems. Indoor and outdoor mean relative humidity of the shelter was recorded more than 70% during every season, and high frequency appears in high relative humidity range over 95%. Such environments seem to have produced dew condensation on the rock surface with rainfall and supply water, promoted physical, chemical and biological weathering along crack and joint, resulting in high permeation of water and percentage of water content. Therefore, it is judged that for scientific conservation of the triad Buddha it needs environment control through persistent preservation environment monitoring including water problem.

• Archives of Plastic Surgery
• /
• v.37 no.2
• /
• pp.115-121
• /
• 2010

Purpose: Many topical agents had been used for contaminated wound treatment. Although antimicrobial ointments were widely used as topical agents, their comparative antibacterial and wound healing effects were largely unreported. The purpose of this study was to compare antibacterial effects and wound healing effects of common topical ointments on infected full thickness skin defect in the mouse. Methods: One full thickness skin defects in the mice (n=60) were developed on the back and left open for twenty-four hours. Sixty mice were divided into four groups: group B (dressing with Bactroban$^{(R)}$, n=15), group I (dressing with Iodosorb$^{(R)}$, n=15), group T (dressing with Terramycin$^{(R)}$, n=15), group G (control group, dressing with dry gauze, n=15). The size of wound defects and the grades of wound healing were evaluated at 4, 7, 10 days, and antibacterial effect was evaluated with restricted zone in Mueller Hinton agar by disk diffusion method. After the wound was left open for twenty-four hours, many Staphylococcus aureus was cultured. The wound defect size was decreased in order of Bactroban$^{(R)}$ (B), Iodosorb$^{(R)}$ (I), Terramycin$^{(R)}$ and gauze dressing group in all days, but difference among experimental groups was not statistically significant. The grade score of wound healing was increased in order of Bactroban$^{(R)}$, Iodosorb$^{(R)}$, Terramycin$^{(R)}$ and gauze dressing group, and the difference was statistically significant. Antibacterial effect for was increased in order of Bactroban$^{(R)}$, Iodosorb$^{(R)}$, Terramycin$^{(R)}$ and gauze dressing group, and the difference was statistically significant. Conclusion: Topical antimicrobial ointments application was effective against wound infections by S. aureus. Bactroban$^{(R)}$ may be an optimal topical treatment for infected wounds according to this study. However, further study is necessary to evaluate the clinical efficacy of antimicrobial ointments and to search for the mechanisms that explain their effects.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.32 no.5
• /
• pp.418-425
• /
• 2006

Purpose: This study was aimed at evaluating the histological changes of new bone and expression of osteopontin (OPN) after mandibular distraction osteogenesis. Materials and Methods: Unilateral mandibular distraction (0.5 mm twice per day for 10 days) was performed in eight adult dogs. Two animals were sacrificed at 7, 14, 28 and 56 days after completion of distraction, respectively. The distracted bones and contralateral non-distracted control bones were harvested and processed for histological and immunohistochemical examinations. Results: The new bone was arranged to tension direction after distraction osteogenesis. 7 days after distraction, numerous osteoblasts lining the immature trabecular bone and fibroblast-like cells in the fibrous intrezone were observed. 14 days after distraction, the new formed trabecular bones were thickened compared with 7 days after distraction. 28 days after distraction, the fibrous interzone was almost filled with newly calcified bone, and it was more hardened at 56 days after distraction. Increased OPN signals detected in the osteoblasts lining the trabecular bone and fibroblast-like cells in the fibrous interzone at 7 and 14 days after distraction. At 28 days after distraction, the OPN was weakly expressed in the osteoblasts, and it was not detected in all cellular components of distracted bone at 56 days later of distraction. Conclusions: After distraction osteogenesis, the distracted zone was completely calcified during the 56 days of consolidation period. In this study, the staining intensity of OPN increased in the osteoblasts and fibroblast-like cells at 7 and 14 days after distraction. The expression pattern of this protein shown here suggested that OPN play an important role in the osteogenesis during the early consolidation period.

• Journal of Korea Port Economic Association
• /
• v.24 no.2
• /
• pp.175-192
• /
• 2008

Today's individual firms no longer compete as solely autonomous entities, but rather as supply chain. As such the competitive position of a port is not only determined by its internal strengths but also it is also affected by its links in a global supply chin. In other words, port competitiveness is becoming increasingly dependent on external coordination and control of the whole supply chain. The main purpose of this paper is to examine how a port embeds itself into supply chain in order to strengthen its competitive position by focusing on Dubai port case. This paper found that Dubai port used three phases-insertion, integration and dominance-as a strategies for how it can embedded into global supply chain successfully. Dubai's global supply chain strategies give some implications for the further development of the Port of Gwangyang. First, the Port of Gwangyang should fully utilize symbiotic relationship with Gwangyang free Economic Zone. Second, the integration between Korea Container Terminal Authority and GYFEZ can be recommended for fast decision-making and providing a one-stop-service. Finally, Gwangyang should pursue an aggressive supply chain strategy, aims at dominance in the regional port network through port alliance with small and medium ports in neighboring area.

• Journal of the Korean Institute of Gas
• /
• v.11 no.1 s.34
• /
• pp.23-28
• /
• 2007

This paper presents an experimental investigation on the sealing defects and cracks of O-rings and a valve packing of a gas valve for a LPG cylinder. O-ring in which stops a gas leakage of a liquefied petroleum gas is very important for a LPG valve safety. Valve packing is to open and close a gas flow port for supplying and charging a LPG fuel. The sealing performance of two sealing units ism related to the leak safety and long lift of a gas valve. The investigated results show that most of O-rings was failed due to a circumferential crack in which is caused by partial press bonding failure near the partition zone and an excess compression rate. Some of the O-ring failure was originated by an extrusion of an excessive leak pressure of a LP gas. Thus, this paper strongly recommends a tight quality control and a safety guarantee system of O-rings and valve packing to guarantee a leak safety and to extend a service lift of a gas valve. At the end, a warranty policy of the sealing units should be adopted for increasing a product quality and safety of a gas valve.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.9
• /
• pp.3815-3821
• /
• 2012

The LCD frame is an important part which supports the BLU of medium/large sized TFT-LCD. To produce it efficiently, it is necessary to achieve the molding process improvement from 1 cavity to 2 cavity system. Because 2 cavity mold is compact and its hot-runner zone is broadened, it is difficult to control the temperature on the mold. In this study, injection molding analysis on the frame in 2 cavity process with FEA(Finite Element Analysis) software is carried out to estimate its quality. The calculated injection molding pressures and maximum deflection in 1 and 2 cavity processes are 41.13 MPa and 1.62 mm, 40.49 MPa and 1.66 mm respectively. The measured maximum flexure load and surface roughness of the left and right frame of 2 cavities are 209 N and 0.08 ${\mu}m$, 193 N and 0.10 ${\mu}m$ while those in 1 cavity are 140 N and 0.13 ${\mu}m$. Thermal image shows that the maximum standard deviation of the temperature on left and right side of 2 cavity mold is $1.23^{\circ}C$. The simulation and measurement results show that the quality of the frame in 2 cavity injection molding process as a whole is not worse than that of 1 cavity system. But maximum flexure loads of the frame in 2 cavity process are far greater than that in 1 cavity process.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.23 no.3
• /
• pp.33-41
• /
• 2015

An alternative was investigated to maximize the treatment efficiency of wastewater treatment plant without large scale expansion. 79% of detention time was required for enough nitrogen control. As aeration time was extended, nitrification was processed, but opposite trend was seen in phosphorus. High concentration of $NO_3-N$ interrupted PAOs activity not to absorb phosphorus. An alternative was devised for selective use of anaerobic or anoxic zone. Trisection was suggested for alternative use of center room. The result was relatively successful. The concentration of phosphorus was reduced with reduction of nitrogen. Extended anaerobic condition seemed to stimulate denitrification. Valve connection of internal return from aeration tank will make it possible to use middle room alternatively. This method will be a good alternative for seasonal variation of water temperature.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.30 no.1
• /
• pp.1-9
• /
• 2020

Objectives: The purpose of this case study is to assess workers' exposure to carbon nanotubes(CNTs) and characterize particles aerosolized during the process of producing CNT-enabled polytetrafuoroethylene(PTFE) composites at a worksite in Korea. Methods: Personal breathing zone and area samples were collected for determining respirable concentrations of elemental carbon(EC) using NIOSH(National Institute for Occupational Safety and Health) Method 5040. Personal exposure to nano-sized particles was measured as the number concentration and mean diameter using personal ultrafine particle monitors. The number concentration by particle size was measured using optical particle sizers(OPS) and scanning mobility particle sizers(SMPS). Transmission electron microscopy (TEM) area samples were collected on TEM grids and analyzed to characterize the size, morphology, and chemistry of the particles. Results: Respirable EC concentrations ranged from 0.04 to 0.24 ㎍/㎥, which were below 23% of the exposure limit recommended by NIOSH and lower than background concentrations. Number concentrations by particle size measured using OPS and SMPS were not noticeably elevated during CNT-PTFE composite work. Instant increase of number concentrations of nano-sized particles was observed during manual sanding of CNT-PTFE composites. Both number concentrations and mean diameters did not show a statistically significant difference between workers handing CNT-added and not-added materials. TEM analyses revealed the emission of free-standing CNTs and CNT-PTFE aggregate particles from the powder supply task and composite particles embedded with CNTs from the computer numerical control(CNC) machining task with more than tens of micrometers in diameter. No free-standing CNT particles were observed from the CNC machining task. Conclusions: Significant worker exposure to respirable CNTs was not found, but the aerosolization of CNTs and CNT-embedded composite particles were observed during handing of CNT-PTFE powders and CNC machining of CNT-PTFE composites. Considering the limited knowledge on the toxicity of CNTs and CNT composite particles to date, it seems prudent to take a precautionary approach for the protection of workers' health.

• Journal of Korean Society of Steel Construction
• /
• v.24 no.6
• /
• pp.693-700
• /
• 2012

In this study, the Charpy impact test along with metallurgical observation was conducted to evaluate low temperature impact toughness of structural steel welds with different welding processes to find out the optimal welding process to guarantee the required impact toughness at low temperatures. The welding processes employed are shield metal arc welding (SMAW) and flux cored arc welding(FCAW), which are commonly used welding methods in construction. The Charpy impact test is a commercial quality control test for steels and other alloys used in the construction of metallic structures. The test allows the material properties for service conditions to be determined experimentally in a simple manner with a very low cost. To investigate the impact toughness at low temperatures of the steel welds, specimens were extracted from the weld metal and the heat affected zone. Standard V-notch Charpy specimens were prepared and tested under dynamic loading condition. The low temperature impact performance was evaluated based on the correlation between the absorbed energy and the microstructure. Analysis of the results showed that the optimal welding process to ensure the higher low temperature impact toughness of the HAZ and the weld metal is SMAW process using the welding consumable for steels targeted to low temperature use.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.18 no.1
• /
• pp.43-52
• /
• 2006

Numerical model tests are done in order to evaluate impact zone of low salinity water on outer region of the developing Saemankeum reservoir. Also saline mixing processes are investigated f3r the inner reservoir with consideration of Mankyoung and Donjin riverine flood discharges when sea water is passing freely through gate. In these analyses 2-d ADCIRC, 3-d TIDED3D and CE-QUAL-ICM models are used. Through models tests, it is found that inner reservoir mixing process caused by inflow of outer sea water occurs gradually. It takes at least one month for complete mixing on Mankyoung part and 6 month on Dongjin part of the reservoir. When Sinsi or Garyeok gates are opened to control inner reservoir level, discharging velocities decrease exponentially from the gates, but show very strong currents of 0.5m/sec to the 10Km region apart. These results imply that hydrodynamic circulation and ecosystem of frontal region of the Saemankeum dike might be affected in amount by gate operations, since low saline inner waters are discharged periodically at ebb tide according to tidal level.