• Clean Technology
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• v.22 no.3
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• pp.168-174
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• 2016

The working environment is deteriorated due to a rise in temperature of a coal mine caused by increase of its depth and carriage tunnels. To improve the environment, the temperature distribution resulted by using the fan type ventilation system aiming for the temperature drop is calculated by using a fluid dynamic analysis program. The analysis shows that A coal mine needs 6,152 m³ min^-1 for in-flow ventilation rate but the total input air flowrate is 4,710 m³ min^-1, 1,442 m³ min^-1 of in-flow ventilation rate shortage and the temperature between the carriage tunnel openings and the workings with exhausting ventilation system type is 2~3 ℃ less than that with blowing ventilation system type. The exhausting ventilation system type would be more effective than blowing ventilation system when the distance between the carriage tunnel openings and the workings is relatively far.

• Tunnel and Underground Space
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• v.29 no.6
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• pp.480-507
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• 2019

This paper aims at optimizing the auxiliary ventilation system in large-opening limestone mines with unducted fans. An extensive CFD and also site study were carried out for optimization at the blind entries. The fan location, operating mode, and layout are the parameters for optimization. Since the jet stream discharged from the auxiliary fan is flowing faster than 15 m/s in most of the cases, the stream collides with floor, sides or roof and even with the jet stream generated from the other fan placed upstream. Then, it is likely to lose a large portion of its inertial force and then its ventilation efficiency drops considerably. Therefore, the optimal fan installation interval is defined in this study as an interval that maximizes the uninterrupted flowing distance of the jet stream, while the cross-sectional installation location can be optimized to minimize the energy loss due to possible collision with the entry sides. Consequently, the optimization of the fan location will improve ventilation efficiency and subsequently the energy cost. A number of different three-dimensional computational domains representing a full-scale underground space were developed for the CFD study. The velocity profiles and the CO concentrations were studied to design and optimize the auxiliary ventilation system without duct and at the same time mine site experiments were carried out for comparison purposes. The ultimate goal is to optimize the auxiliary ventilation system without tubing to provide a reliable, low-cost and efficient solution to maintain the clean and safe work environment in local large-opening underground limestone mines.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.07a
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• pp.124-129
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• 1999

지난 몇 십년간 생물계 폐기물 호기성 처리의 경제적이고 실용적인 공법으로 가축분뇨처리에 적용되어온 유기성 폐자원의 호기성 분해공정은 축산환경 보전, 지력증강 자원의 고갈 및 지구온난화문제 등에 의해서 더욱 주목받아 오고 있다. 특히, 기존의 호기성 고형폐기물 처리시설에서 저투입, 고효율의 처리시설을 개발하여 보다 많은 숙성퇴비를 얻을 수 있는 통기퇴적식 퇴비화 시설은 강제통풍 통기방식으로 호기성 미생물의 분해시간을 단축하고 암모니아가스 휘산을 저감하는 등의 탁월한 처리효율을 나타내었다(Brinton et al., 1995). (중략)

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.32 no.10
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• pp.7-16
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• 2003

사무소, 주상복합건물, 호텔, 백화점, 공항, 병원의 용도별로 다른 6개 건물의 배수통기 설계사례를 소개하였다. 최근 생활수준의 향상과 산업 발전으로 점차 물 사용량이 증가하고 있으며, 배수 종류 또한 다양해지고 있다. 이에 수반해서 생기는 배수를 건물내에 체류시키지 않고 신속히 배제하는 배수설비와 배수설비의 기능을 완수하기 위해 설치되는 통기설비의 적정 설계방안을 모색해보고자 한다.(중략)

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.32 no.10
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• pp.31-35
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• 2003

배수설비시스템에 적용되는 각종 기기들의 특징 및 통기관의 선정 방법을 미국의 ASPE code에 제시되어 있는 내용을 중심으로 소개하고자 한다. 건물 내에서 발생하는 오수 및 배수는 항상 건물 외부로 잘 배출시켜야 한다. 이러한 배수시스템은 원활한 배수가 수행되어야 하도록 수평배수관은 적합한 구배를 주어야 하며, 부지경계선 밖에 설치된 공공하수도와 체결하여 한다. 오수배관은 지상에 노출시키거나 사설정화조를 체류하지 않고 우수로에 직접 배출할 수 없다. 배수설비를 설계할 때의 문제점은, 배수배관 및 통기관을 선정시 선정된 관경이 최적화되었는지 평가하는데 있다. 즉, 현존하는 건축물의 배수시스템에서 문제점이 발생하지 않는다고 설계된 배수배관경 및 통기관경이 최적화된 것으로 평가하기에는 어려움이 있다고 판단된다.(중략)

• Korean journal of applied entomology
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• v.45 no.1 s.142
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• pp.67-74
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• 2006

Korean entomopathogenic nematodes were introduced into cultural management of turfgrasses to enhance white grub control in golf courses for saving labour and expenses and contribution to giving safe playing and working places for golfers and superintendents by environmentally friendly control strategy. The turfgrass height influenced efficacy of entomopathogenic nematodes. Efficacy was higher at short turfgrass both in pot using Galleria mellonella larvae and in golf courses using 2nd instar of Exomala orientalis and Ectinohoplia rufipes as baits. Aeration increased the efficacy of entomopathogenic nematodes which were lower virulent. Pre-aeration was more effective than post-aeration. Exomala orientalis larval population was reduced 80.4 and 66.0% in the pre-aeration and post-aeration with entomopathogenic nematode, Steinernema carpocapsae Pocheon strain compared to 35.4% in the no aeration treatment.

• Tunnel and Underground Space
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• v.27 no.1
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• pp.12-25
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• 2017

In local underground mines heavily depending on the natural ventilation, ducted fan auxiliary ventilation system is strongly recommended instead of the total mine ventilation system requiring large capital and operating costs. Optimizing the installation of ducted fans in series in long large-opening mines is required to assure the economy and efficiency of the ventilation system. The two most critical design parameters for optimization are the wall separation distance and gap length between adjoining ducts. This study aims at deriving the optimal values for those two parameters concerning the economic and environmental aspects through the extensive CFD analysis, which minimizes pressure loss, leakage and entrainment of the contaminated air in the gap space. The ranges of the wall separation distance and gap length for study are selected by taking into consideration the existing recommendations and guidelines. The ultimate goal is to optimize the auxiliary ventilation system using ducted fans in series to provide a reliable and efficient solution to maintain clean and safe workplace environment in local long underground mines.

• Tunnel and Underground Space
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• v.27 no.4
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• pp.217-229
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• 2017

This study focuses on the improvement of the working environment in domestic collieries where temperature is increasing due to heat of the earth that is caused by the long-term mining. In order to improve the working environment of the mine, a ventilation evaluation was carried out for Hwasoon Mining Industry. In order to increase the ventilation efficiency of the mine, numerical analysis of the effect on temperature was carried out by using climsim, a temperature prediction program. The analysis shows that A coal mine needs $6,152m^3/min$ for in-flow ventilation rate but the total input air flowrate is $4,710m^3/min$, $1,442m^3/min$ of in-flow ventilation rate shortage. The 93 m hypothetical ventilation shaft from -395 ML to -488 ML could result about $3^{\circ}C$ temperature drop in the coal mine of -488 ML far. As a result of predicting the $CO_2$ concentration at -523 ML development using artificial neural network, the emission of $CO_2$ increased as the amount of coal and coal bed thickness increased. The factors that have the greatest effect on the amount of $CO_2$ emissions were coal layer thickness and coal mining. And, as the air quantity increases, it has a great effect on the decrease of carbon dioxide concentration.

• Korean Chemical Engineering Research
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• v.59 no.4
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• pp.542-547
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• 2021

Glass lined impellers are corrosion resistant to most chemicals, including strong acids, and also have a smooth, non-stick surface, easy to clean and free from impurities in the process. Glass lined home base impeller is a multi-purpose impeller designed to stir a wide viscosity range of liquids from low viscosity fluids to high viscosity fluids, among others, cell culture, yeast culture, and beer fermentation pots, especially used for air-water system breathable stirring. The glass lining for HB impellers, which are simple in structure and competitive in performance, is essential to have upper and lower division in order to make the joint area between the impeller and shaft as small as possible. The upper and lower division of the impeller hardly affects the mixing performance, but the aeration performance. In this study, in order to optimize the shape of the Glass Lining HB impeller, a study was conducted on the effect of the angle between the upper and lower impellers, the clearance between the impellers, and the number of baffles on the aeration power. The optimal shape and baffle plate conditions for the Glass lined HB impeller were derived through the study results that the angle and the clearance between the upper and lower impellers decreased the ration of the power consumption with aeration P_g and that without aeration P₀, P_g/P₀.

• Journal of the Korean Chemical Society
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• v.54 no.1
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• pp.137-141
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• 2010

Generally, polymer materials are not air-permeable and hydrophilic. In addition, they do not possess anti-fungal property. Hydrophilicity, air-permeability, and anti-fungal properties of new composites consisting of polymer, ceramic nanoparticles, and silver ion were investigated by contact angle measurements, air permeation time, and cell culture. The hydrophilic, air-permeable, and anti-fungal composites can be used in health care industry.