• Journal of the Korea Concrete Institute
• /
• v.15 no.1
• /
• pp.1-10
• /
• 2003

The purpose of this study is to evaluate the capacities of repaired structural walls with different shear span ratios(1, 2, 3). Experimental tests were carried out. In this study three isolated large-scale wall specimens were made. The original wall specimens were tested until the drift reaches more than 3%. The region of the damaged specimen with the crack larger than 0.2 mm is replaced by new concrete. Also, severly distorted reinforcements were also replaced by new reinforcements. The crack smaller than 0.2 mm was cured by epoxy resin. Because of the space limitation of the laboratory the dimensions of all walls are the same. The shear-span ratio was controlled by the combination of axial and lateral force using the special test setting. All specimens were tested using the incremental quasi static cyclic load until failure occurs. Test results show that strength of repaired walls was almost equivalent to that of original walls. However, deformation capacities of repaired wall specimens are inferior to the original wall specimens.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.45 no.12
• /
• pp.1031-1038
• /
• 2017

In order to improve the performance of the air breathing engines, it is important to maximize the total pressure recovery through air intake. In this study, we investigated whether the Oswatitsch method, which guarantees the maximum pressure recovery for supersonic intake, is effective at hypersonic speed by compressing the intake air with the same intensity at each ramp. The non-linearity of the shock wave normal Mach number at each ramp stage was analyzed by comparing the compression ramp angle and the number of ramp to the inflow Mach number in terms of compressible thermodynamics and the operation limits of the inlet. Based on this analysis, the Oswaitisch technique yields valid conditions not only in supersonic but also hypersonic flight regime.

• Journal of Life Science
• /
• v.20 no.11
• /
• pp.1667-1674
• /
• 2010

Influence of nitrate on growth, chlorophyll content, content and activity of rubisco and rubisco activase of tobacco plant cultured on MS medium treated with cadmium in vitro was studied. In vitro growth and chlorophyll content reduced at 0.2 mM Cd was recovered by nitrate and this recovery was most significant at 80 mM nitrate. Rubisco content at 80 mM nitrate was more increased compared to that at other concentrations. A similar change was also shown in rubisco activity. These resultsindicate that the activation and induction of rubisco reduced by Cd were recovered by nitrate. The degree of intensity of 55 and 15 kD polypeptides identified as the large and small subunits of rubisco by SDS-PAGE analysis at 80 mM nitrate was significantly higher than that at other concentrations. The content and activity of rubisco activase at 80 mM nitrate was significantly increased than that at other concentrations. These data suggest that the recovery effects of rubisco by nitrate may be associated with rubisco activase.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.5
• /
• pp.412-419
• /
• 2017

Purpose:This study was conducted to identify the effects of theSemi-Fowler's position on post-operative recovery and pain for patients with laparoscopic abdominal surgery Methods: This study utilized a non-equivalent control group non-synchronized design to validate the effects of theSemi-Fowler's position. After IRB approval, 56 patients took part in this study, 29 in the experimental group and 27 in the control group. Consent was obtained from the participants. The Semi-Folwer's position was applied to experimental group and the supine position was applied to the control group for 24 hours after surgery. All data were reviewed retrospectively from April to June 2016. Collected data, frequency, percentage, average, standard deviation, chi-squared test, independent t-test and repeated measures ANOVA were conducted using SPSS 20.0. Results: There was no significant difference between the experimental and control group with regard to recovery outcomes; however, there was a significance differencebetween groups and among check times with regard to post operational pain. Conclusion:The results of this study provide information that will be usefulto the development of strategies for improving recovery outcomes and pain for laparoscopic operation patients.

• Journal of the Korean Applied Science and Technology
• /
• v.32 no.3
• /
• pp.497-504
• /
• 2015

Apart from hydrates, asphaltenes, and inorganic minerals, paraffinic waxes are also very important in flow assurance area. Evaluation of wax gel behavior has been important as off-shore oil recovery becomes more popular in oil production. Restart after either planned or emergency shutdown requires pump operation in high pressure since a waxy oil forms troublesome gel. In this paper, vane method is introduced to determine wax gel strength by determining yield stress. Prediction of gel strength are discussed in qualitative and quantitative manners.

• Computational Structural Engineering
• /
• v.1 no.2
• /
• pp.131-142
• /
• 1988

This study was carried out to investigate the long-term deformation of superplasticized concrete. Compressive strength, shrinkage, creep and creep recovery of concretes with and without the superplasticizing admixture have been compared for one year. The test results on creep of superplasticized concrete were also compared with three methods of predicting creep; the ACI model, the CEB model and the BP model. According to test results, superplasticized concrete has good results in compressive strength at an age of 28 days of more than 22%, drying-shrinkage cured at air-conditioned storage less than 15%, creep deformation in air conditioned storage and loaded at an age of 28 days to 15% of compressive strength less than 11% of control concrete.

• Journal of Power System Engineering
• /
• v.10 no.1
• /
• pp.60-64
• /
• 2006

Alumina ceramic for textile machinery was sintered and subjected to three-point bending. A semicircular surface crack was made on each sample. Crack-healing behavior was systematically studied, as a function of crack-healing temperature and crack size. The bending strength and fracture toughness of the crack-healed sample from $1200^{\circ}C\;to\;1400^{\circ}C$ were investigated. A statistical approach based on Weibull distribution was applied to the test data to evaluate the dispersion in the fracture toughness. Alumina ceramic for textile machinery have the ability to heal after cracking, from over $1300^{\circ}C$. The material can completely heal a $65{\mu}m$ diameter semielliptical crack. The fracture toughness could be explained by 2-parameter Weibull distribution.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.10 no.3
• /
• pp.80-92
• /
• 2007

Forest fire is the dominant large-scale disturbance mechanism in the Korean temperate forest, and it strongly influences forest structure and function. Moreover burn severity incorporates both short- and long-term post-fire effects on the local and regional environment. Burn severity is defined by the degree to which an ecosystem has changed owing to the fire. Vegetation rehabilitation may specifically vary according to burn severity after fire. To understand burn severity and process of vegetation rehabilitation at the damaged area after large-fire is required a lot of man powers and budgets. However the analysis of burn severity in the forest area using satellite imagery can acquire rapidly information and more objective results remotely in the large-fire area. Space and airbone sensors have been used to map area burned, assess characteristics of active fires, and characterize post-fire ecological effects. For classifying fire damaged area and analyzing burn severity of Samcheok fire area occurred in 2000, Cheongyang fire in 2002, and Yangyang fire in 2005 we utilized Normalized Burn Ratio(NBR) technique. The NBR is temporally differenced between pre- and post-fire datasets to determine the extent and degree of change detected from burning. In this paper we use pre- and post-fire imagery from the Landsat TM and ETM+ imagery to compute the NBR and evaluate large-scale patterns of burn severity at 30m spatial resolution. 65% in the Samcheok fire area, 91% in the Cheongyang fire area and 65% in the Yangyang fire area were corresponded to burn severity class above 'High'. Therefore the use of a remotely sensed Differenced Normalized Burn Ratio(${\Delta}NBR$) by RS and GIS allows for the burn severity to be quantified spatially by mapping damaged domain and burn severity across large-fire area.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.25 no.4
• /
• pp.437-444
• /
• 2009

The purpose of this study was to evaluate the physical properties of different automixing resin cements and the shear bond strength on dentin. For this study, two self-adhesive automixing resin cement(Rely-X Unicem(3M ESPE, St. Paul, USA), Embrace resin cement(Pulpdent, Oakland, USA)) and one chemical polymerizing resin cement(Resiment Ready-Mix(J.L.Blosser Inc., Liberty Missouri, USA)) were used. To evaluate the physical properties, compressive strength, diametral tensile strength and flexural strength were measured. The specimens were fabricated using Teflon mould according to manufacturers' instructions and stored for 24 hours in an atmosphere of 100% humidity. To evaluate the shear bond strength on dentin, each cements were adhered to buccal dentinal surface of extracted human lower molars in 2mm diameter. Physical properties and shear bond strengths were measured using universal testing machine(Z010, Zwick GmbH, Ulm, Germany) at a crosshead speed of 0.5mm/min. The physical properties and shear bond strength of different automixing resin cements were statistically analyzed and compared between groups using One-way ANOVA test and Schffe post-hoc test at the 95% level of confidence. The result shows that chemical polymerizing automixing resin cement represents the relatively higher physical properties and shear bond strength than self-adhesive automixing resin cements.

• Journal of KIISE:Software and Applications
• /
• v.37 no.7
• /
• pp.568-572
• /
• 2010

Self-healing is one of the techniques that assure dependability of mission-critical system. Self-healing consists of fault detection and fault recovery and fault detection is important first step that enables fault recovery but it causes overhead. We can detect fault based on model, the detection tasks that notify system's behavior and compare normal behavior model and system's behavior are heavy jobs. In this paper, we propose architecture-based multi-level self-adaptive monitoring method that complements model-based fault detection. The priority of fault detection per component is different in the software architecture. Because the seriousness and the frequency of fault per component are different. If the monitor is adapted to intensive to the component that has high priority of monitoring and loose to the component that has low priority of monitoring, the overhead can be decreased and the efficiency can be maintained. Because the environmental changes of software and the architectural changes bring the changes at the priority of fault detection, the monitor learns the changes of fault frequency and that is adapted to intensive to the component that has high priority of fault detection.