• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.629-636
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• 2022

Domestic eco-friendly vehicles currently account for 5.8% of the total registered vehicles in Korea. Hydrogen vehicles, one of the representative eco-friendly vehicles, have grown rapidly as they have been expanded to the market based on the government's policy to boost the hydrogen industry. Therefore, it is time to expand the safety review of hydrogen vehicles in various directions according to the increase in supply. In this study, the effect of internal heat damage was analyzed when a jet flame was generated by a hydrogen car in a road tunnel. It was simulated using Fluent, and the amount of jet flame injection was selected in consideration of the hydrogen tank capacity of commercial hydrogen vehicles for road tunnels. In addition, the study was conducted with the direction of the jet flame and the nozzle distance from the tunnel wall as variables. From the results, when the jet flame erupted in the road tunnel, high radiant heat emission of more than 20 kW/m² was generated in most areas within ±5 m in the longitudinal direction based on the vehicle (spray nozzle) and 5 to 7 m in the lateral direction based on the adjacent tunnel wall.

• Journal of Life Science
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• v.31 no.10
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• pp.960-968
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• 2021

Since microalgae research started on late 18 century, they have been recognized as one of the most important bioresources used in bioindustry. Owing to the large efforts paid to industrial application of this microorganisms, their importance on food/feed and bioactive compounds has been further extending into the environmental research areas including alternative energy resources, mitigation of the carbon emission, and waste-water treatment. However, despite the importance on their industrial application, the fundamental research field related to the long-term preservation of microalgae culture has not received much attention. However, a less labor intensive and cost-efficient preservation technology enabling biologically active and stable microalgae-culture provides a key success factor in the biotechnological application. Therefore, this study investigated various cutting-edge microalgae cryopreservation technologies currently developed so far, mainly targeting Chlorophyta, which occupies the largest taxon in the classification system of microalgae. In addition, for the development of successful cryopreservation technique, the key factors such as temperature control effect and preservative effect during cryopreservation of microalgae culture were investigated. In addition, the problems with current preservation technology that is being used in Korean domestic biological resource banks and the international microalgal resource banks are described. According to our investigation, currently no standard method for long-term preservation of microalgae is available due to their various morphological and physiological characteristics. To overcome such issues, much more efforts on fundamental research area on the identification of specific biomarker used for microalgae taxonomical classification and further systemic approaches based on strain-specific cryopreservation methods needed.

• Journal of the Korean Institute of Gas
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• v.25 no.4
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• pp.27-35
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• 2021

Recently, as a solution to the sharp drop in "power reserve ratio", it is being converted to a microgrid that enables bi-directional transmission and distribution. A microgrid is composed of a small-scale distributed power supply and a load. As a representative technology of distributed power generation, there is a Micro Combined Heat and Power system applied to homes and buildings. In this study, a safety standard was developed by dividing the power generation system, cooling system, lubrication system, and exhaust system to derive safety standards for a small gas engine power generation system with a gas consumption less than 232.6kW (200,000 kcal/h). In the case of the power generation system, a filter was installed and the system was stopped by detecting gas leakage and abnormalities in engine speed or output and the cooling system is stipulated to stop the system in case of insufficient cooling water or overheating. The lubrication system monitors the pressure and temperature of the lubricating oil and stops the system when an abnormality occurs, and the exhaust gas emission concentration regulation value was specified in accordance with domestic and foreign standards. Through the results of this study, it is judged that the safety of the gas engine power generation system can be improved and it can contribute to the commercialization of products.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1307-1319
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• 2018

As interests in the air pollution increases, many kinds of researches are underway on the reduction of air pollutants. The removal of nitrogen oxides from the emission gas of diesel vehicles using urea solution has shown a great effect. The quality of urea solution is strictly defined by domestic law, but the increase of impurities in urea solution reduces the effect of reducing nitrogen oxides. Therefore, in this study, the change of physical properties of urea solution was analyzed after heating the urea solution for a certain temperature and time. Also, the changes of physical properties of urea solution were analyzed according to kinds of storage container and temperature for storing the urea solution. After heating the urea solution for a certain period of time, the biuret content in urea solution increased and the content of urea decreased. As the urea content decreased, both density and refractive index decreased. In the storage stability test carried out at a constant temperature with iron and PET containers, no change in physical properties was observed.

• Journal of the Korean Institute of Gas
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• v.25 no.2
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• pp.34-41
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• 2021

In order to cope with the problems that may occur when the natural gas used in Korea becomes low in calories, the problems that may have to the domestic industrial gas equipment must be identified in advance, and based on this, countermeasures for efficient use of energy must be preceded. In this study, in order to solve the problem of deterioration of engine output performance and efficiency due to the introduction of low calorific gas when using a lean-burning natural gas engine that complies with the EURO-6 regulation, specific control plans and results based on the experiment are intended to be presented. In order to identify the improvement effect by the control variable represented by the ignition timing under the full load condition at the engine speed of 1,400 rpm and 550 Nm, 2,100 rpm, which is the engine speed at the rated operation condition, the thermal efficiency and exhaust gas characteristics were identified and optimized by changing the ignition timing for each gas fuel. In the case of pure methane, which shows the lowest value based on the torque under the full load condition, if the ignition timing is advanced by about 2 CAD from the reference ignition timing, the torque can be compensated without a large increase in NOx emission.

• Resources Recycling
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• v.31 no.3
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• pp.40-52
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• 2022

This study analyzed the amount of carbon dioxide reduction and economic benefits of detailed processes of CO₂ 6,000 tons plant facilities with mineral carbonation technology using carbon dioxide and coal materials emitted from domestic circulating fluidized bed combustion power plants. Coal ash reacted with carbon dioxide through carbon mineralization facilities is produced as a complex carbonate and used as a construction material, accompanied by a greenhouse gas reduction. In addition, it is possible to generate profits from the sales of complex carbonates and carbon credits produced in the process. The actual carbon dioxide reduction per ton of complex carbonate production was calculated as 45.8 kgCO₂eq, and the annual carbon dioxide reduction was calculated as 805.3 tonCO₂, and the benefit-cost ratio (B/C Ratio) is 1.04, the internal rate return (IRR) is 10.65 % and the net present value (NPV) is KRW 24,713,465 won, which is considered economical. Carbon mineralization technology is one of the best solutions to reduce carbon dioxide considering future carbon dioxide reduction and economic potential.

• Journal of The Korean Society of Agricultural Engineers
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• v.64 no.3
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• pp.25-32
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• 2022

To understand the distribution characteristics of PM_2.5 concentration in the Saemangeum Reclamation Area and nearby areas, three points of the background area, the occurrence area, and the affected area were selected and samples were collected for each season. The chemical composition was determined. As a result of analyzing the chemical composition contained in PM_2.5, NO₃^- (7.2 ㎍/m³), SO₄^2- (4.3 ㎍/m³), NH₄+ (4.3 ㎍/m³), OC (2.5 ㎍/m³), Si (1.3 ㎍/m³) m³) and EC (0.5 ㎍/m³) seemed to be the main components, and NO₃-, SO₄^2-, NH₄⁺, which are components that form secondary particles, occupied a large proportion. The composition ratio of PM_2.5 was investigated in the order of ion component (56.8%) > Unknown (27.4%) > carbon component (11.8%) > heavy metal component (4.0%). During the PM_2.5 high concentration case days, the ionic component accounted for 90.7% during atmospheric stagnation cases, whereas the chemical composition ratio was in the order of ionic component (51.7%) > heavy metal component (41.5%) > carbon component (6.8%) during yellow dust cases. It was found that the characteristic of PM_2.5 in the Saemangeum reclaimed land and surrounding areas is mainly influenced by outside (domestic and overseas) throughout the year. Ion components accounted for the largest portion of PM_2.5 components in this area, but there were few sources of SOx and NOx emission in the Seamangeum area, which are precursors for secondary particle formation. Therefore, it is judged that most of these are generated and influenced as a secondary reaction in the atmosphere from the outside.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.5
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• pp.809-818
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• 2022

The number of ships using liquefied natural gas (LNG) as fuel is increasing to respond to the International Maritime Organization's (IMO) air pollutant emission regulations. At the same time, the need to expand LNG bunkering infrastructure for stable fuel supply and demand for ships is emerging. LNG bunkering is carried out in three ways: truck to ship (TTS), pipe to ship (PTS), and ship to ship (STS). In foreign countries, all three methods are being carried out, but in Korea, LNG bunkering is carried out only with the TTS method owing to the lack of infrastructure. LNG bunkering is a high-risk operation. For safe bunkering operations, the competence of the workers is extremely important, and a professional training course is required to strengthen the competence. This study was conducted to design training contents for LNG bunkering workers for fostering LNG bunkering experts and performing safe and systematic bunkering work. To this end, the current status of LNG-fueled ships and bunkering was identified, and related domestic and abroad educational contents were analyzed. In addition, opinions on the importance of educational contents were collected through expert questionnaires. Consequently, we designed training contents suitable for various training targets and divided them into basic and advanced training courses, with a duration of 4 days, and proposed. Based on the designed training contents, if additional research is conducted by sufficiently reflecting Korea's bunkering environment, it will be of great help to improve the competence of LNG bunkering workers and to foster human resources.

• Analyses & Alternatives
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• v.7 no.2
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• pp.179-207
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• 2023

Carbon neutrality, the international community's practical challenge in response to climate change, is becoming a key industrial strategy for the future development of nations. Despite concerns that China, as an economic powerhouse in the G2, may face challenges leading global climate change efforts due to its high-carbon-emitting industrial structure, it is leveraging carbon neutrality to enhance its industrial competitiveness. The Chinese government has formulated national policies for achieving carbon neutrality and detailed sector-specific plans to implement them. In particular, it aims to leverage carbon neutrality industrial strategies as a lever for adjusting the domestic industrial structure and fostering new industries, at the same time responding to international climate norms and external pressures. However, the effectiveness of carbon-neutral industrial strategies is expected to vary based on regional conditions such as economic and industrial levels. This article analyzes the regional conditions for implementing carbon neutrality in China, as well as the contents and characteristics of major industrial policies. Due to differing levels of economic development and industrial structures, significant variations in carbon emissions, size, emission sources, and efficiency are inevitable across regions. These disparities introduce diverse initial conditions and endogenous factors in pursuing carbon-neutral goals, limiting the direction and implementation of carbon-neutral industrial strategies favoring certain regions. In particular, the extent of policy autonomy granted to local governments regarding carbon neutrality implementation will influence the regional dynamics of central-local environmental governance. Consequently, it is crucial to emphasize regional monitoring alongside comprehensive national research to accurately navigate the path towards carbon neutrality in China. In summary, the article underscores the importance of understanding regional variations in economic development, industrial structure, and policy autonomy for successful carbon neutrality implementation in China. It highlights the need for regional monitoring and comprehensive national research to determine a more precise direction for achieving carbon neutrality.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.801-824
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• 2022

Recently, United Nations found that 38% of global carbon emissions are generated in the building sector, surpassing other industries (32%) and transportation (23%), and ESG is actively used as a way to reduce carbon emissions in the building sector, led by overseas advanced countries. In Korea, as the National Pension Service announced "Consider ESG with more than 50% of investment assets" this year, the move to introduce ESG in the building sector is accelerating, centering on construction companies and asset management companies. However, as the domestic ESG evaluation system is still mainly focused on corporate governance and social responsibility, interest in the environmental sector is lagging behind that of advanced countries. As ESG in the building sector is expected to grow rapidly over the next 10 years, I would like to suggest the following development directions. The first is the expansion of the incentive system. In order for the government to successfully implement policies related to ESG in the building sector, incentive system such as tax reduction and building standards should be expanded further than now in addition to negative systems such as rent restrictions and punishment taxes due to regulatory violations. Second, standardized ESG standards are established. Rather than creating an independent Korean ESG standard that is far from global standards, it is necessary to organize the common parts of global standards and evaluation methods and create and provide guidelines in the form of standard textbooks that can be used equally by all stakeholders. Third, it is an effort to link ESG in the building sector with Digital Transformation(DX). This is because actual energy savings and carbon emission reduction can be realized only when the operation method of the building sector, which is operated mainly by manpower, is digitalized and converted to an intelligent way.