• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.552-558
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• 2016

Recently, the repair and reinforcement of deteriorated concrete buildings has attracted much interest. In order to accurately evaluate the safety of these existing structures, it is essential to know the strength of the concrete that they are composed of. The core drilling method is considered to be the most effective and common method of assessing the compressive strength of concrete. In general, the regulations do not permit the core specimens within reinforcing bars to be used to assess the strength of the concrete, even if the core specimens contain reinforcing bars in some cases. The purpose of this study is to investigate the effects of the reinforcement arrangement on the compressive strength of concrete, and to propose the quantitative specific standard of strength for core specimens containing reinforcements, in order to facilitate their safe inspection by repair or retrofit companies who want to evaluate the soundness of the structures. To complete this research, one type of cylinder specimen without reinforcement and 14 types of specimens with reinforcement arrangements were prepared and their compressive strength evaluated. It was found that the strength of the cylinders with reinforcement volumes of up to $50cm^3$ (about 4-ϕ13mm) was more than 80% of that of the cylinders without any reinforcement.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.866-873
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• 2017

Exhaust regulations of automobile are being reinforced increasingly as environmental problems issues came to the fore by industrial development. However, it is known that the exhaust emission is not only influenced by the system of automobile but also the fuel properties. In particular, high-performance engines have required high-performance fuels with high lubricity as CRDI engines(diesel engine) have been developed and commercialized. This paper have examined that the fuel property variations affect a major parts and an exhaust gas of automobile. It was confirmed that the high pressure pump, the injector and the DPF(diesel particulate filter) were damaged and fuel efficiency was get worse due to use the fuel of lacking lubricity property($651{\mu}m$/quality standard: less in $400{\mu}m$). In addition, through an iron component was detected in the broken DPF, it was estimated that the breakage of the DPF was caused by the excessive exhaust of the particulate matter due to the iron component of the fuel.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.228-228
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• 2015

Water reuse plays significant role in water saving and water environmental protection, and it helps alleviate the shortage of water resources. China's water reuse was put into practice since 1980s by means of pilot and promotion in National Fifth-year Plan and other strategies. The effects of water reuse is beneficial in both economic, social and environmental aspects. But some shortcomings still undermine future development of water reuse in China. To overcome and boost water reuse, Ministry of Water Resources conducted a successive survey across China. The aim of this study is to demonstrate the current condition of water reuse in China in construction, funds, legislation, planning, policy aspects, to summarize problems and its reasons underneath, to make suggestions for further development. Basically, in 2010, China's water reuse is 2.83 billion cubic meters and the utilization rate is 10.35%. Water reuse in China has four major characteristics: the first one is water reuse differences in amount occur national-widely and North of China has the main percentage as 47.3%; the second one is water reuse is mainly in environment maintenance (42.1%) and industry cooling (29.8%); the third one is funds for water reuse station and pipe construction is main in non-fiscal budget which take percentage as 56.8%; the fourth one is progresses of administrative system, political system, price management, standard system and technologies go rapidly recently. The problems of water reuse such as lack in water reuse station, delay in pipe constriction and limits on water reuse amount still exist due to some reasons. As a think tank of Ministry of Water Resources, we give some suggestions: firstly, water reuse needs to be integrated with traditional water resources allocation; secondly, public budgets need to be strengthened and income mechanism should also be constructed; thirdly, water resources integrated administrative of city and county should be boosted and roles as water reuse need to be clear and precise; fourthly, national, provincial and regional water reuse planning should be made in time; fifthly, regulations on water reuse should be programmed as soon as possible.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.898-904
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• 2021

This experimental study aims to investigate the use of a wet electrostatic precipitator as a post-treatment device to satisfy the strict emission regulations for sulfur oxides and particulate matter (PM). The inlet/outlet of a wet electrostatic precipitator was installed in a funnel using a marine four-stroke diesel engine (STX-MAN B&W) consuming marine heavy fuel oil (HFO) with a sulfur content of about 2.1%. Measurements were then obtained at the outlet of the wet electrostatic precipitator; an optical measuring instrument (OPA-102), and the weight concentration measurement method (Method 5 Isokinetic Train) were used for the PM measurements and the Fourier transform infrared (FT-IR; DX-4000) approach was used for the sulfur oxide measurements. The experimenst were conducted by varying the engine load from 50%, to 75% and 100%; it was noted that the PM reduction efficiency was a high at about 94 to 98% under all load conditions. Additionally, during the process of lowering the exhaust gas temperature in the quenching zone of the wet electrostatic precipitator, the sulfur dioxide (SO₂) values reduced because of the cleaning water, and the reduction rate was confirmed to be 55% to 81% depending on the engine load.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.744-753
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• 2021

This study suggests ways to improve the standard test method and judgment criterion for the "Eco-toxicity Test" based on the rules and regulations provided in 'performance and qualifying test standards for marine pollution prevention materials and chemicals' in the Republic of Korea. Compared with the relevant references of other countries, this study attempted to find the limitations in the existing standards. As for the growth inhibition test of algae using Skeletonema costatum as an indicator, applying comparative analysis to measure specific growth rates, together with statistical analysis, instead of applying current methods, judged by the appearance of colors from the culture medium was suggested. Considering the exponential growth phase of the test species, the test duration was suggested to be reduced to less than four days. For the test with fish as an indicator, resetting the appropriate body size was suggested to, show consistent sensitivity against chenicals applied during testing. Furthermore, it is necessary to consider the criteria needs, which should be established in reasonable and objective ways. For the testing species, marine rotifer, Brachionus plicatilis could be a replacement for Artemia sp., and a bivalve for fish in the test. To improve the performance effectiveness of the "Eco-toxicity test", it is worth considering the designation of accredited testing institutes, by placing it in the same loop. Thus it is also expected to have a reliable management system in place, having the capacity of cost calculation properly and adjusting testing items if required.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.6
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• pp.773-782
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• 2019

Basel III (Third Basel Accord or Basel Standards) is a global, voluntary regulatory framework on bank capital adequacy, stress testing, and market liquidity risk. Basel III regulatory ratios include capital adequacy, asset soundness, and liquidity. The capital adequacy variables include BIS capital adequacy ratio, BIS tier 1 capital ratio, and tangible common equity ratio. The asset soundness variables include non-performing loan ratio and non-performing loan coverage ratio. The liquidity regulation variables include KRW liquidity coverage ratio and foreign currency liquidity coverage ratio. This study aims to investigate how capital adequacy standard affects efficiency of internet primary banks. As a result of this study, BIS capital adequacy ratio of domestic internet primary banks is lower than that of commercial banks. In order to maintain sustainable operation considering capital adequacy regulations, it is necessary to expand additional capital. In addition, the delinquency rate and non-performing loan ratio of domestic internet primary banks is gradually increasing due to the maturity of high-yield loans in 2019.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.90-98
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• 2021

Since 2017, the Occupational Safety and Health Act has been fully applied to school food services, and risk assessments have been implemented since 2019. The introduction was slow compared to other industries and was evaluated by non-professional nutritionists, so there was a limit to establishing the system. All schools under the Seoul Metropolitan Office of Education apply the KRAS every year in accordance with the OSH Act for school foodservice and a notice from the Ministry of Employment and Labor. A risk assessment is applied according to legal regulations. On the other hand, the effectiveness of risk assessment has been questioned because the frequency and intensity criteria of the risk are qualitative and subjective. Based on the accident statistics of catering workers, the frequency and intensity criteria of risk were presented quantitatively and objectively, and a risk assessment was conducted by applying a new calculation standard for some work during the catering service and compared with current risk assessment results. The risk was increased, and the improved effectiveness was confirmed by the specific suggestions for improvement. Thus, the pilot evaluation for the entire food service should be expanded, and the feasibility confirmed. The pilot evaluation should be applied to all schools to enhance the effectiveness and operability of the risk assessment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.4
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• pp.433-440
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• 2019

Offshore working environments such as ships, offshore oil and gas plants, and offshore wind turbines are isolated and directly exposed to rough seas, which pose high risks of safety accidents. Therefore, all workers in offshore plants should be able to cope with emergency situations and must be qualified according to relevant laws and regulations such as the International Convention on Standards of Training, Certification and Watchkeeping for Seafarers (STCW Convention) and Offshore Petroleum Industry Training Organization (OPITO) standards. In particular, marine workers should be able to perform cardiopulmonary resuscitation (CPR) in isolated locations or enclosed and confined spaces such as those in life-boats, life-rafts, rescue-boats, etc. Because the floor material is made of rubber, it may be difficult to perform chest compressions in life-rafts used to escape from emergency situations in ships or offshore plants. Chest compressions performed on life-rafts may reduce the accuracy of CPR and increase fatigue for those providing aid. To measure the accuracy and fatigue of those performing CPR in life-rafts, 15 experimenters with more than five years of experience as first aid instructors were exposed to different CPR environments in a marine safety training center equipped with an artificial wave generator. The results showed that the accuracy of CPR in the classroom was 99.6 %, but that in various life-raft environments was only 84 %. T-verification of the two sites confirmed the reduced accuracy of CPR performed on life-rafts. CPR on life-rafts should be performed in groups of two and with the use of automated chest compression devices.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.841-847
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• 2018

Since global energy consumption and demand for energy have dramatically risen, a focus on environmental problems and sustainability has become more important. Clean and renewable energy sources such as offshore wind power generation have received attention among new renewable energy options as alternative energy resources. Due to maintenance and operational perspectives, offshore wind farms have been planned for installation in many coastal waters. However, development of offshore wind farms faces interference from existing maritime traffic along the planned areas. In order to safely and effectively govern marine traffic in the vicinity of wind farms and inner areas, standard criteria are suggested to allow vessels to sail the internal waters of offshore wind farm areas. Therefore, the purpose of this study is to establish allowable criteria for sailing vessels and safety zones for offshore wind farms by investigating the local regulations of various offshore wind farm cases overseas. The commended inner safety zone of wind farms is proposed to be a distance of 150 % of the rotation diameter of the wind turbine rotor and a distance of 200 m from the outer wind turbine for the outer safety zone. Besides this, the allowable criteria for sailing vessels within a wind farm is proposed to have an air draft of 14.47 m south-west wind farm sea areas for a minimum margin to avoid hull contact through evaluation of the tide and height of a wind turbine. further studies will be needed to establish vessel sailing criteria among adjacent offshore wind farms as well as vessel sailing criteria within a single offshore wind farm.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.75-83
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• 2019

In order to fulfill the obligation to voluntarily reduce greenhouse gas emissions under the Paris Climate Agreement, the proportion of coal and nuclear power generation is reduced worldwide and national efforts are being made to spread renewable energy including solar power generation. Korea also intends to increase the proportion of renewable energy generation to 30~35% by 2040 by introducing laws and regulations. In addition, while the country is trying to apply solar power generation to sidewalks and roads, there is no research related to it in Korea. Therefore, as a precedent study to develop solar power generation roads, solar power generation concrete blocks applicable to sidewalks and plazas were developed and the applicability was evaluated by constructing them on the site. As a result of indoor experiment, compressive strength was measured by 25.5~35.7MPa and flexural strength was measured by 5.1~10.5MPa, which showed that all domestic standards were satisfied. However, the higher the unit cement amount, the lower the strength was measured according to the mixing of the broken fine aggregate. The absorption rate was 5.7%, which satisfied the domestic standard of 7% or less. As a result of the freeze-thawing test, the reduction rate of the compressive strength after 100 cycles was up to 6.3%. As a result of measuring the settlement amount after construction, the maximum of 2.498mm was measured and irregular settlement occurred in the overall area, which is because the resolution of the sand layer was poor during construction. Maintenance techniques of sidewalk concrete block and solar panel need to be established more efficiently through long-term operation in the further.