• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.443-451
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• 2021

This study compared and analyzed the thermal characteristics based on the ratio of moisture content of infected and non-infected Bursaphelenchus Xylophilus by heat of combustion experiment. The experiment results are as follows. The analysisresult of the ratio of water content shows that 19.92% on average for infected Bursaphelenchus Xylophilus and 26.27% for non-infected which decreases water content as the size of conduction, convection, and radiant heat increases in case of fire. As the vaporization of the moisture content accelerates, the average moisture content is reached, and the result is contrary to the thermal characteristics of the wood that the moisture content is not ignited by a heat source when the moisture content is under 15%. The combustion heat analysis result showed that infected and non-infected Bursaphelenchus Xylophilus had no significant difference in combustion heat at about 3%. However, it shows that combustion heat is higher than other species. In conclusion, decreasing in moisture content based on the increasing conduction, convection, and radiant heat is one of the direct causes of ignition, and the lower the moisture content, the faster the fire spreads.

• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1901-1922
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• 2021

Since most large earthquakes occur by reactivation of preexisting active faults, it is important to understand the locations and characteristics of active faults in terms of earthquake hazard research and earthquake disaster prevention. Recently, several remote sensing techniques are broadly used for lineament analysis performed prior to field surveys in active fault surveys. The aim of this paper is introducing simple principles and application examples of each remote sensing technique (satellite remote sensing, airborne remote sensing, InSAR, LiDAR) widely used for active fault investigation. This paper also explains the analytical methods for the slope break generated by fault activity based on GIS and the horizontal displacement of the strike-slip fault. In discussion, we would like to discuss the problems and solutions on making DEM based on aerial photography, and a new developed technique (RRIM) to overcome the problems of DEM based on aerial LiDAR. Understanding remote sensing techniques used for active fault investigation and utilizing appropriate methods depending on the situation and limitations of each remote sensing technique are important for effective active fault investigation.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.439-449
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• 2021

The recent reduction in greenhouse gases, interest in environmental pollution such as low-carbon emission policies is increasing. Accordingly, the penetration rate of eco-friendly vehicles, including hydrogen battery vehicles capable of reducing carbon emission, is increasing, and thus it is required for disaster prevention and safety-related measures. In this study, the degree of risk for the concentration distribution of hydrogen when leaking hydrogen fuel vehicles according to ventilation conditions was analyzed through numerical analysis, limited to places in parking lots. As a result, when only one hydrogen tank was released, the combustible volume ratio of hydrogen in the underground parking lot was up to 8.6%, and as ventilation continued, the volume ratio of combustible hydrogen decreased to less than 1% after 150 seconds, indicating that mechanical ventilation is essential. In the case of simultaneous release or stage release of three hydrogen tanks, the final combustible volume ratio of hydrogen is similar, but the increase in the combustible volume ratio of hydrogen in the early stage of release is low, and further research is expected.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.76-83
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• 2021

This study examines the bending behavior of lap-spliced ultra-high-strength fiber-reinforced concrete members and evaluates the safety of the design codes for ultra-high-strength fiber-reinforced concrete structures. An experiment on a total of six beams was performed. The main variables were the fiber-inclusion and the lap-spliced length at the center of the beams. The steel fibers in a volume fraction of 2% were used, and the lap-splice lengths were determined to be 8db and 16db. As a result of the test, the specimens not reinforced with fiber lost abrupt load-bearing capacity at the lap region and did not experience yielding of the reinforcing bar. In the case of fiber-reinforced concrete, if a lap-splice length of 16db is secured, the yielding of the main reinforcing bar can be experienced, and appropriate flexural strength can be expressed. Based on the experimental results of this study, as a result of reviewing the lap-splice length calculation formulas of the current design standards and the ultra-high-strength concrete structural design recommendations, it was found that all of them were evaluated conservatively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.60-67
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• 2021

In lately, it's been developed and used a system of using deck plates as formwork in order to solve various problems caused by conventional formwork system. This system is more economical and has higher constructability than the conventional system by permanently embedding most of deck plates into the members. However, for this kind of embedded deck plates formwork system, it's been reported that it is difficult to verify filling of concrete in members like beams with narrow width and complicated rebar arrangement. In addtion, there are several problems such as corrosion of deck plates in terms of constructability and maintenance. Therefore, in this study, it is attempted to develop a removal-deck plate formwork system for beams by removing deck plates after concrete curing. The system consists of a deck plate module that acts as form, a frame preventing deformation by concrete lateral pressure, stirrup frame, and connector that combines these. As a result of this research, it is verified that it has higher constructability, efficiently prevents deformation caused by concrete lateral pressure and could be easily removed in the developed formwork system.

• Journal of the Korean earth science society
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• v.40 no.2
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• pp.109-118
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• 2019

Cloud-aerosol interactions are considered to be one of the most important forcing mechanisms in the climate system. However, there is considerable disagreement on the magnitude and even on the sign of how aerosol perturbations affect cloud fraction and lifetime. Furthermore, aerosol effects on clouds and precipitation are not readily separable from the effects of meteorology. This review paper summarizes the study of precipitation susceptibility $S_o$, which qualifies how aerosol perturbations alter the magnitude of the precipitation rate (R) while minimizing the effects of macrophysical factors such as cloud depth (H) and liquid water path (LWP). The analysis shows that the precipitation susceptibility $S_o$ for the warm marine boundary layer clouds is insensitive to aerosol perturbations at low LWP (equivalently low H). However, R decreases as aerosols increase at intermediate LWP. This is because aerosols act as cloud seed and produce numerous small-sized particles, which impede the collision and coalescence process that leads to precipitation. At high LWP, $S_o$ decreases with increasing LWP as there are enough water contents in the clouds. The LWP or H dependent $S_o$ behavior differs depending on the predominant cloud physics processes in the clouds.

• Journal of the Korea Institute of Building Construction
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• v.18 no.6
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• pp.611-619
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• 2018

The researches have only conducted regarding construction safety management and risk on interior construction site(workers) and is insufficient about the exterior construction site(third party). As a result, ordinary people who were near construction sites have injured and hold a negative view when they think about the construction industry because construction industry have been exposed to them having a high accidents rate through media. In addition, the importance of industrial disaster prevention is emphasized at this point in time, the overall safety management system should be constructed with considering construction site external(third human) for improving the negative image of the construction industry among ordinary people. Therefore, the objective of this study is to develop the quantification model of human accident utilizing the insurance claim payout occurred construction site exterior(third party). In the future, it can be used as a reference for developing the safety management checklist in construction site interior exterior and development for forecasting control system of human accident.

• The Journal of the Korea Contents Association
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• v.19 no.3
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• pp.114-125
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• 2019

The frequency of official injury of fire-fighting officers exposed to an extreme situation in disaster areas has been continuously increased. In spite of increase of injury, procedures of injury approval are complex, so the working environment of fire-fighting officers is very poor in terms of safety management. This study was, therefore, conducted to provide basic data for improvement of the injury management system for fire-fighting officers, by empirically analyzing the system for those in Busan city. The findings of the empirical analysis are as follows: first, the frequency of injury experienced by them is higher than that of other occupations; second, application for injury is not actively made; third, fire-fighting officers should bear the expense if injury is approved. On the basis of such an analysis on actual conditions, an analysis on policy factors for improving the injury management system shows; first, various high-risk matters should be considered in the review of application for injury, for improvement factors of the application for injury, while it is necessary to extend the benefit and support project for injured officers, for operation improvement factors of the injury management system, and the compensation act should be improved, for the improvement factors of the injury system. Second, it is urgent to develop damage prevention and coping education program for improving the injury management system. In addition, the simplification of administrative procedures of application for injury and the extension of benefit and support project for injured officers should be realized as soon as possible, moreover, the enhancement of directors' interest and support is also required.

• Journal of the Korean Geosynthetics Society
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• v.17 no.4
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• pp.293-304
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• 2018

This paper described a results of field test based on plate bearing test of the restoration material, which was developed to restore the ground cavity due to sewerage damage. The analysis of bearing capacity characteristics on the restoration materials was performed by experimental results. The results showed that the load bearing capacity in the maximum stress condition of the foundation ground is about 66%-70%, when the expansion mat is embedded at the bottom of 0.1 m and 0.2 m from the ground surface. However, The load bearing capacity of expansion mat according to embedded depth was not large. The load bearing capacity of concrete mats was about 82%-90% compared with that of ground surface, and it showed about 50% of the load bearing capacity compared with the expansion mat. As a result of analysis of allowable bearing capacity according to restoration materials, it was confirmed that the allowable bearing capacity of the expansion mat and the concrete was about 130%-150% and about 160% more than the foundation ground, respectively.

• Journal of Korea Water Resources Association
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• v.52 no.3
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• pp.227-234
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• 2019

The vulnerability of urban disasters is increased with the rapid urbanization and industrialization, and the extreme rainfall event is increased due to the global climate change. Urban inundation is also increased due to the extreme rainfall event beyond the capacity limit of facility for the damage prevention. The underground detention vault and the underground drain tunnel are rapidly being utilized to prevent urban inundation. Therefore, the hydraulic review and design analysis of the inlet of the underground facility are important. In this study, the water level of the approach flow according to the inflow discharge is measured and the flow characteristic of the inlet (tangential and spiral) is analyzed. For the spiral inlet, the multi-stage is introduced at the bottom of the inlet to improve the inducing vortex flow at low discharge conditions. In case of the tangential inlet, the discharging efficiency is decreased rapidly with hydraulic jump in the high flow discharge. The rising ratio of the water level in the multi-stage spiral inlet is higher than the tangential inlet, but the stable discharging efficiency is maintained at low and high discharge conditions. And the empirical formula of water level-flow discharge is derived in order to utilize inlets used in this study.