• Fire Science and Engineering
• /
• v.32 no.1
• /
• pp.89-98
• /
• 2018

Fire accidents in foreign countries, like the accident in a thermal power plant in Beijing, the accidents in domestic power plants, including Boryeong Power Plant in 2012 and Taean Power Plant in 2016, a disaster in a nuclear power plant in Fukushima in 2011 or the large-scale power failure in California in 2001 are safety accidents related to electric power, which caused losses in the people's stable lives and the countries. Electricity has an absolute impact on the people's life and the economy, so we can easily expect the serious situation affecting economic growth as well as direct damage to the protection of the people's lives and the losses of properties, if there are fire or explosion accidents or radioactive leak because of negligence in safety management, or problems because of natural disasters like an earthquake in power plants that generate electricity. In this study, it was drawn the improvement of the organizations exclusively in charge of firefighting, the operation of a program for the improvement of professional competency, the development of a customized firefighting management system for plants for systematic firefighting safety management and the improvement of the earthquake-proof correspondence system, which has recently become an issue, as measures for improvements through a survey of the actual conditions concerning the necessity of the construction of a firefighting safety management system for power plants with five power generation companies, including Korea Southern Power Co., Ltd., and the persons in charge of firefighting safety Korea Hydro & Nuclear Power Co., Ltd.

• The Journal of the Korea Contents Association
• /
• v.19 no.12
• /
• pp.84-92
• /
• 2019

The deterioration of the urban heat environment due to climate change and the occurrence of heat-related diseases have emerged as one of the major social problems. This has led to more research on climate change, including heat waves, but it is mainly focused on climate factors. However, the urban heat island phenomenon accelerates the summer heat wave, and the increasing trend of heat-related patients in urban areas suggests the impact of the city's environment. Thus, this study analyzed the effects of physical and social characteristics of urban areas on heat-related patients in Seoul and Gyeonggi-do. The analysis showed that the ratio of the total area of residential, commercial and industrial facilities, the main source of heat energy locality, among the land use statuses, was not statistically significant, but the road area and the green area were found to have a positive and negative The population density and the percentage of people aged 65 or older, the percentage of people living alone and the proportion of people receiving basic living were all shown to be significant, with only the ratio of elderly living alone and the ratio of population density having negative effects. The results of the study can be used to develop urban policy alternatives related to local warming patients.

• Polymer(Korea)
• /
• v.32 no.3
• /
• pp.251-255
• /
• 2008

This study suggested antistatic material which can increase anti-static properties and mechanical strength by mixing polystyrene for conveying electronic stuffs with metal salt and ester compound as a anti-static agent. We studied about mechanical, thermal and electrical characteristics by changing the contents of MAH of poly(styrene-co-maleic anhydride), compatibilizer. As the result of measuring residue space charge of the blends of HIPS(75)/TPU(25)/poly(styrene-co-maleic anhydride)(MAH weight ratio : 25, 32, 43.5 wt%), we could find small residue charge in the blend which MAH(25 wt%) was added and it showed the highest values in tensile strength. Additionally we found out the material to which compatibilizer was added kept better anti-static properties than one to which compatibilizer was not added. In the event we could confirm that the adding of PS-co-MAH enables two polymers were mixed well when HIPS/TPU was blended and anti-static agent made easier dissipative in the blend.

• Polymer(Korea)
• /
• v.37 no.4
• /
• pp.518-525
• /
• 2013

To improve the mechanical properties of polypropylene (PP) biocomposites reinforced with sulfuric acidtreated green algae (SGA), SGA/graphite nanoplatelets (GNP)/PP biocomposites were prepared and their properties were evaluated depending on the particle size and content of GNP. The flexural and impact strength of SGA/GNP/PP biocomposites decreased with the addition of GNP, whereas the flexrual and storage moduli were greatly improved with increasing GNP loading. SGA/GNP/PP biocomposites reinforced with GNP5 showed generally better mechanical properties compared to that reinforced with GNP15 mainly due to the improved dispersion of the smaller GNP. SGA/GNP/PP biocomposites reinforced with GNP5 showed a lower resistance to the thermal expansion because the relatively uniform dispersion of smaller GNP was responsible for the effective heat transfer to the polymer matrix. As a result, SGA/GNP/PP biocomposite was acceptable for the general purpose application due to the improved flexural resistance, storage moduli, and damping characteristics.

• Journal of the Korean earth science society
• /
• v.30 no.4
• /
• pp.464-477
• /
• 2009

In this study, we examined the patterns of local circulation over the Daechung lake area through the numerical experiment designed to investigate the impact of lake on the local circulation. The results of numerical experiment showed that the surface temperature predicted by WRF model was lower than the observation, while the wind speed was stronger than the observation. The local circulation over the lake area was characterized by a lake breeze induced by a horizontal thermal contrast between the lake surface and the Surrounding land. At Daecheong Lake, a lake breeze formed at 09 LST and dissipated at 18 LST, with maximum intensity at 15 LST. The vertical extent of the simulated circulation was about 1,200 m. The specific humidity increased as the humid air above the lake moved landward due to the daytime circulation of the lake breeze. The numerical experiments of sensitivity to existence of the lake showed that the simulated surface temperature decreased in the experiment with the lake. Wind speed was more intense around the lake area when the actual land use was substituted by grassland land use. The results of numerical experiments suggest that the lake-induced lake breeze circulation has an effect on the meteorology of planetary boundary layer around the lake.

• Journal of the Korean Institute of Gas
• /
• v.20 no.6
• /
• pp.23-30
• /
• 2016

The conventional natural gas engine realized lean combustion for the improved efficiency. However, in order to cope with exhaust gas regulations enforced gradually, the interest has shifted at the stoichiometric mixture combustion system. The stoichiometric mixture combustion method has the advantage of a three-way catalyst utilization whose purification efficiency is high, but the problem of thermal durability and the fuel economy remains as a challenge. Hydrogen-natural gas blend fuel (HCNG) can increase the rate of exhaust gas recirculation (EGR) because the hydrogen increases burning speed and lean flammability limit. The increase in the EGR rate can have a positive impact on heat resistance of the engine due to the decreased combustion temperature, and further can increase the compression ratio for efficient combustion. In this study, to minimize the exhaust emission developed HCNG engine with stoichiometric combustion method, developed three-way catalyst was applied to evaluate the conversion characteristics. The tests were carried out during the steady state and transient operating conditions, and the results were compared for both the conventional and proto-three-way catalyst of HCNG engine for city buses.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.1
• /
• pp.81-88
• /
• 2020

Flight data recorder is a equipment that records data required for investigation of aircraft accidents and should be developed in compliance with the ED-112A standard. Unlike general data storage device, flight data recorder must be able to recover data after an aircraft accident, requiring a housing and a memory board to protect data in extreme environments. To attain this performance, we designed a housing that can withstand the test by analyzing the physical environment of the impact, shear/tensile, penetration resistance and static crush test of the crash survival test and minimized the size and weight compared to the existing one in consideration of the installation of the aircraft in this paper. Insulation material and thermal block material were applied to endure high and low temperature fire so that the internal temperature does not rise above 150℃ even in 260℃, 10 hour environment. In addition, the memory board is designed to minimize the size and we devise a hoping programming method to prevent continuous data loss of more than 16 seconds. Through this, Crash protected memory module that satisfies ED-112A was completed.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.8 no.2
• /
• pp.68-76
• /
• 2006

A thermal time-based two-step phenological model was used to project flowering dates of Japanese cherry in South Korea from 1941 to 2100. The model consists of two sequential periods: the rest period described by chilling requirement and the forcing period described by heating requirement. Daily maximum and minimum temperature are used to calculate daily chill units until a pre-determined chilling requirement for rest release is met. After the projected rest release date, daily heat units (growing degree days) are accumulated until a pre-determined heating requirement for flowering is achieved. Model calculations using daily temperature data at 18 synoptic stations during 1955-2004 were compared with the observed blooming dates and resulted in 3.9 days mean absolute error, 5.1 days root mean squared error, and a correlation coefficient of 0.86. Considering that the phonology observation has never been fully standardized in Korea, this result seems reasonable. Gridded data sets of daily maximum and minimum temperature with a 270 m grid spacing were prepared for the climatological years 1941-1970 and 1971-2000 from observations at 56 synoptic stations by using a spatial interpolation scheme for correcting urban heat island effect as well as elevation effect. A 25km-resolution temperature data set covering the Korean Peninsula, prepared by the Meteorological Research Institute of Korea Meteorological Administration under the condition of Inter-governmental Panel on Climate Change-Special Report on Emission Scenarios A2, was converted to 270 m gridded data for the climatological years 2011-2040, 2041-2070 and 2071-2100. The model was run by the gridded daily maximum and minimum temperature data sets, each representing a climatological normal year for 1941-1970, 1971-2000, 2011-2040, 2041-2070, and 2071-2100. According to the model calculation, the spatially averaged flowering date for the 1971-2000 normal is shorter than that for 1941-1970 by 5.2 days. Compared with the current normal (1971-2000), flowering of Japanese cherry is expected to be earlier by 9, 21, and 29 days in the future normal years 2011-2040, 2041-2070, and 2071-2100, respectively. Southern coastal areas might experience springs with incomplete or even no Japanese cherry flowering caused by insufficient chilling for breaking bud dormancy.

• Tunnel and Underground Space
• /
• v.21 no.5
• /
• pp.394-405
• /
• 2011

In this paper, we applied coupled non-isothermal, multiphase fluid flow and geomechanical numerical modeling using TOUGH-FLAC coupled analysis to study the complex thermodynamic and geomechanical performance of underground lined rock caverns (LRC) for compressed air energy storage (CAES). Mechanical stress in concrete linings as well as pressure and temperature within a storage cavern were examined during initial and long-term operation of the storage cavern for CAES. Our geomechanical analysis showed that effective stresses could decrease due to air penetration pressure, and tangential tensile stress could develop in the linings as a result of the air pressure exerted on the inner surface of the lining, which would result in tensile fracturing. According to the simulation in which the tensile tangential stresses resulted in radial cracks, increment of linings' permeability and air leakage though the linings, tensile fracturing occurred at the top and at the side wall of the cavern, and the permeability could increase to $5.0{\times}10^{-13}m^2$ from initially prescribed $10{\times}10^{-20}m^2$. However, this air leakage was minor (about 0.02% of the daily air injection rate) and did not significantly impact the overall storage pressure that was kept constant thanks to sufficiently air tight surrounding rocks, which supports the validity of the concrete-lined underground caverns for CAES.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.4
• /
• pp.76-85
• /
• 2019

Recently, various investigation of vegetable oil which is extracted from natural resources is being progressed because of its low cost and environmental aspect. However, double bonds in vegetable oil should be substituted to other high reactive functional group due to its low reactivity for synthesizing bio-polymeric materials. ${\alpha}$-eleostearic acid, which is consist of conjugated triene, is the main component of tung oil, and the conjugated triene allows tung oil to have higher reactivity than other vegetable oil. In this study, tung oil is copolymerized with styrene and divinylbenzene to make thermoset resin without any substitution of functional group. Thermal and mechanical properties are measured to investigate the effects of the composition of each monomer on the synthesized thermoset resin. The result shows that the products have only one Tg, which means the synthesized thermoset resins are homogeneous in molecular level. Mechanical properties show that tung oil act as soft segment in the copolymer and make more elastic product. On the other hand, divinylbenzene acts as hard segment and makes more brittle product.