• Resources Recycling
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• 제30권1호
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• pp.35-43
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• 2021

In this study, Na2SO4 and KCl reagents were used to synthesize K2SO4 as a basic study for recycling byproducts generated during the manufacture of steel and cement. The mole ratio of Na2SO4 to KCl, the saturation of the solution, and the stirring temperature were controlled to derive the optimal manufacturing conditions. The microstructure and crystallinity of the materials prepared were evaluated using scanning electron microscopy and X-ray diffraction analysis. Pure K2SO4 was obtained when the mole ratio of Na2SO4 to KCl was 1:6-18, the saturation of the solution was less than 160%, and the stirring temperature was 20℃, 50℃. The optimal manufacturing conditions to maximize the crystallinity and yield of K2SO4 while minimizing the energy consumption were 1:6 mole ratio of Na2SO4 to KCl, 140% saturation of the solution, and 20℃ stirring temperature.

• Clean Technology
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• 제24권4호
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• pp.301-306
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• 2018

Recently, due to the increase in the fine dust, regulations on PM generated from diesel cars are strengthened. There is a growing interest in diesel particulate filters (DPFs), a post-treatment device that removes exhaust gases from diesel vehicles. Therefore, one of the enhancements of the DPF efficiency is to reduce the pressure drop in the DPF, thereby increasing the efficiency of the filter and regeneration. In this study, the effect of cell density, channel shape, wall thickness, and inlet channel ratio of 5.66" SiC and Cordierite DPF on the pressure drop in DPF was investigated using ANSYS FLUENT simulator. As a result of the experiment, the pressure drop was smaller at 300 CPSI than 200 CPSI, and the anisotropy and O / S cell showed less than Isotropy by pressure drop of about 1,000 Pa. As the porosity increased by 10% the pressure drop was reduced by about 300 Pa and as the wall thickness increased by 0.05 mm, the pressure drop was increased by about 500 Pa.

• Environmental and Resource Economics Review
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• 제27권4호
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• pp.695-723
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• 2018

Recently, extreme weather due to climate change has become more frequent, and increase of fine dust has worsen air quality in Korea. Therefore, not only negative perception on coal-fired power generation is dominant, but also the social acceptance of nuclear power generation declines. This study aims at deriving consumer preferences on the mid and long term power mix with various energy sources. Willingness to pay for each generation source was estimated and the preference heterogeneity of consumers was examined by using mixed logit and latent class models. Mixed logit estimation results show that the preference heterogeneity of consumers is especially large for the nuclear power relative to renewable or coal energy. According to the estimation results from the latent class model, group 1 prefers renewable energy while group 2 prefers coal energy. Group 3 shows lexicographic preference which means restricted rationality. As for the policy implication, it is necessary to understand the preference heterogeneity of consumer groups in planning the mid to long term power mix.

• Journal of Korean Society of Disaster and Security
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• 제13권4호
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• pp.47-63
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• 2020

This study aimed to investigate the effects of social disaster risk perception levels of Koreans on government trust. To this end, differences in disaster risk perception levels based on social disaster types and the effects of social disaster risk perception levels on government trust were analyzed. In the preliminary survey, three types of social disasters with high risk levels (bird flu, fine dust, and nuclear power plants) were selected. The survey was conducted on 1,109 Korean men and women aged 20 years and older. First, the analysis results demonstrated that social disaster perception levels differed based on social disaster types. Second, the results showed that, in terms of social disasters, proactivity, personal knowledge, familiarity, severity, fear, and risk associated with chances of recovery did not affect government trust. Third, the perception of delayed social disaster risk had a positive effect on government trust. Fourth, scientific knowledge about social disasters, control capabilities, lethality, and risk perception at the onset time had a negative effect on government trust. In conclusion, the implications and limitations of this study were discussed.

• Journal of the Architectural Institute of Korea Structure & Construction
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• 제34권1호
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• pp.61-68
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• 2018

Recently, concentration of fine and ultra-fine particulate matter(PM) has been increased in KOREA. The increase of PM in KOREA is due to increase of domestic industries and yellow dust from china. PM is known to cause diseases such as dyspnoea, asthma, arrhythmia. Since PM is harmful to human, KOREA Ministry of Environment(ME) warns people to stay indoors when the outdoor PM concentration is high. However, prior studies has shown that indoor PM concentration can be relatively high when outdoor PM concentration is high due to infiltration of PM into buildings though leakage areas. In this study, airtightness, indoor and outdoor pressure difference and PM 2.5 & 10 concentration were measured in an apartment complex to observe PM infiltrating into building. Field measurement was conducted in newly-built apartment buildings to avoid the influence of indoor PM which can be generated by residents. The airtightness test was conducted to identify the leakage areas of the apartment, such as electric outlets and supply/exhaust diffusers. The airtightness test result showed that the air leakage area of the building was dominant in buildings envelop. According to indoor and outdoor pressure difference measurement result and PM concentration measurement result, it can be concluded that outdoor PM can infiltrate into indoor by leakage areas when wind is blown toward the apartment. As a result, pressure difference formed by the external weather condition and architectural characteristics such as the airtightness in building can influence PM to infiltrate into buildings. In further studies, I/O ratio, stack-effect, infiltration and penetration factor will be considered.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제23권12호
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• pp.1687-1692
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• 2019

In the era of the fourth industrial revolution, advanced technologies such as the Internet of Things(IoT) and big data are emerging. However, the level of application of IoT to indoor environment is very weak. Therefore, it is necessary to develop a system for analyzing air pollutants or indoor air quality through real-time monitoring using the IoT. This paper implements a system that measures indoor environmental values using Arduino and various sensors, and stores the information obtained from various sensors into a database of server. The information stored in the server was built as a database and utilized in the ventilation system or air cleaner installed in the home or company's room. In the proposed system, it is possible to check the immediate indoor environmental condition through the LED status display of the monitoring sensor module while reducing the cost of the sensor used to implement IoT technology.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• 제21권1호
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• pp.181-187
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• 2021

Recently, various air pollution factors have been measured and analyzed to reduce damages caused by it. In this process, many missing values occur due to various causes. To compensate for this, basically a vast amount of training data is required. This paper proposes a statistical techniques that effectively compensates for missing values generated in the process of measuring ozone, carbon dioxide, and ultra-fine dust using a small amount of learning data. The proposed algorithm first extracts a group of meteorological data that is expected to have positive effects on the correction of missing values through statistical information analysis such as the correlation between meteorological data and air pollution level factors, p-value, etc. It is a technique that efficiently and effectively compensates for missing values by analyzing them. In order to confirm the performance of the proposed algorithm, we analyze its characteristics through various experiments and compare the performance of the well-known representative algorithms with ours.

• Korean Journal of Remote Sensing
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• 제36권6_3호
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• pp.1681-1690
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• 2020

A scanning lidar system has been developed. The system has two wavelength observation channels of 532 and 1064 nm and is capable of 360-degree horizontal scanning observation. In addition, an analysis method that can classify the measured particle as an indicator of coarse-mode particle (PM2.5-10) and an indicator of fine-mode particles (PM2.5) and calculate the mass concentration of each has been developed by using the backscatter coefficient at two wavelengths. It was applied to the data calculated by observation. The mass concentrations of PM10 and PM2.5, which showed a distribution of 22-110 ㎍/㎥ and 7-78 ㎍/㎥, respectively, were successfully calculated in the Ulsan Onsan Industrial Complex using the developed scanning lidar system. The analyzed results showed similar values to the mass concentrations measured on the ground around the lidar observation area, and it was confirmed that high concentrations of 80-110 ㎍/㎥ and 60-78 ㎍/㎥ were measured at points discharged from factories, respectively.

• Journal of Environmental Impact Assessment
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• 제31권5호
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• pp.334-342
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• 2022

The stringent air environment conservation act forced to build an indoor dome for coal storage. However, it causes some problems due to accumulation of fly ash and harmful substances inside. To solve this problem, this study analyzed the pattern of internal airflow and the amount of ventilation for an indoor coal yard. Overall, the airflow inside the indoor coal yard tended to move to the southwest facing the mountain. In addition, sea-breeze was blowing from the northern louver window facing the sea, where airflow was flowing in. The total flow rate flowing into the indoor coal yard was 918,691 m³/h, and the number of natural ventilation per hour was 0.6 times. Therefore, it is proposed to install a forced ventilation device at the location where internal air flow is concentrated.

• International Journal of Computer Science & Network Security
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• 제22권10호
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• pp.214-222
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• 2022

In these proceedings, we will address the problem of air pollution on the premises of the Cement factory SHARRCEM L.L.C. in Hani Elezit in the Republic of Kosovo respectively around the clinker cooler, rotary kiln, and raw material mill. By air pollution, we mean the introduction of chemicals, particles, or other harmful materials into the atmosphere which in one way or another causing damage to the development of plants and organisms. Air pollution occurs when certain substances are released into the air, which depending on the quantitative level, can be harmful to human health, animals, and the environment in general. The analysis of air shows the influence of the extractive and processing industry on the chemical composition of air. Parameters analyzed though under control such as the case of carbon dioxide, due to the increasing production capacity of cement, the production of hundreds of thousands of cubic meters of CO₂ gas made CO₂ production a concern. With the purchase of the latest technology by the SHARCEM Factory in Hani Elezit, the amount of air pollution has been reduced and the allowed parameters of environmental pollution have been kept under control. Air pollutants are introduced into the atmosphere from various sources which change the composition of the atmosphere and affect the biotic environment.The concentration of air pollutants depends not only on the quantities that are emitted from the sources of air pollution but also on the ability of the atmosphere to absorb or disperse these emissions. Sources of air pollutants include vehicles, industry, indoor sources, and natural resources. There are some natural pollutants, such as natural fog, particles from volcanic eruptions, pollen grains, bacteria, and so on.