• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.657-668
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• 2023

It's important to note that air compressors in the industrial sector are major energy consumers, accounting for a significant portion of total energy costs in manufacturing plants, ranging from 12% to 40%. To address this issue, researchers have compared forecasting models that can predict the power consumption of air compressors. The forecasting models were designed to incorporate variables such as flow rate, pressure, temperature, humidity, and dew point, utilizing statistical methods, machine learning, and deep learning techniques. The model performance was compared using measures such as RMSE, MAE and SMAPE. Out of the 21 models tested, the Elastic Net, a statistical method, proved to be the most effective in power comsumption forecasting.

• Prospectives of Industrial Chemistry
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• v.14 no.3
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• pp.25-36
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• 2011

압축공기 중의 수분은 공압설비의 모든 요소에 중대한 해를 입히며 밸브의 고착, 계기의 막힘 또는 공압기기의 오작동을 일으키며 생산하는 제품의 질에 있어서도 많은 해를 입혀서 제품의 질을 떨어뜨리는 역할을 하게 된다. 따라서 수분을 제거하는 방법이 필요하며 기존의 냉동식 및 흡착식을 대신하여 분리막 법이 적용될 수 있다. 현재 제습용 기체분리막 모듈은 적용이 시작된 단계에 있다. 제습용 기체분리막은 의료기기, 분석기기, Instrument air 장비에 응용이 진행되고 있다. 최근 들어 선진각국 뿐만 아니라 국내에서도 막소재 개발, 복합막 개발, 모듈 개발, 시스템 설계 및 제작 기술 개발이 진행되고 있다. 현재로서는 제습막공정에 적합한 막소재의 개발이 시급하지만 이후 적용확대를 위해서는 제습용 기체분리막의 신뢰성 향상을 위한 다각도의 노력이 필요하다.

• Corrosion Science and Technology
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• v.23 no.2
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• pp.83-92
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• 2024

A hot-dip simulator was utilized to replicate abnormal coating buildup observed during line stops at galvanize lines, assessing the influence of processing conditions on buildup (up to 14 mm/side). Steel samples from 19 coils (comprising IF, BH, LCAK, HSLA, DP600-DP1180, Si: 0.006 - 0.8 wt%, P: 0.009 - 0.045 wt%) were examined to explore the phenomenon of heavy coating growth. It was discovered that heavy coating buildup (~3 mm/h) and rapid strip dissolution (~0.17 mm/h) in a GA or GI pot can manifest with specific combinations of steel chemistry and processing conditions. The results reveal the formation of a unique coating microstructure, characterized by a blend of bulky Zeta crystals and free Zn pockets/networks due to the "Sandlin" growth mechanism. Key variables contributing to abnormal coating growth include steel Si content, anneal temperature, dew point in heating and soaking furnaces, Zn pot temperature, Zn bath Al%, and cold-rolling reduction%. At ArcelorMittal Dofasco galvanize lines, an automatic online warning system for operators and special scheduling for incoming Si-bearing steels have been implemented, effectively preventing further heavy buildup occurrences.

• New & Renewable Energy
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• v.8 no.2
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• pp.14-23
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• 2012

The TMY (Typical Meteorological Year) for the solar energy study is generated using observation data with 22 solar sites from KMA (Korea Meteorological Administration) during 11 years (2000-2010). The meteorological data for calculation the TMY are used solar radiation, temperature, dew point temperature, wind speed and humidity data. And the TMY is calculated to apply the FS (Finkelstein and Schafer) statistics and RMSE (Root Mean Squared Error) methods. FS statistics performed with each point and each variable and then selected top five candidate TMM months with statistical analysis and normalization. Finally TMY is generated to select the highest TMM score with evaluation the average errors for the 22 whole points. The TMY data is represented average state and long time variations with 22 sites and meteorological data. When TMY validated with the 11-year daily solar radiation data, the correlation coefficient was about 0.40 and the highest value is 0.57 in April and the lowest value is 0.23 in May. Mean monthly solar radiation of TMY is 411.72 MJ which is 4 MJ higher than original data. Average correlation coefficient is 0.71, the lowest correlation is 0.43 in May and the highest correlation is 0.90 in January. Accumulated annual solar radiation by TMY have higher value in south coast and southwestern region and have relatively low in middle regions. And also, differences between TMY and 11-year mean of is distributed lower 100 MJ in Kyeongbuk, higher 200 MJ in Jeju and higher 125 MJ in Jeonbuk and Jeonnam, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2323-2327
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• 2010

The experimental apparatus consists of dehumidifier with multi-layer type heat exchangers to remove the moisture from automatic equipments, semiconductors, and manufacturing processes under the low temperature environment, and chemical production lines which are likely to take moisture. The major components of this system are four evaporators with different fin pitch, two compressors, two condensers and an expansion valve. In this study, the performance characteristics of dehumidifier is analyzed by the variations of frontal air velocity in the first heat exchanger(evaporator). The cooling capacity of each heat exchanger is acquired by the enthalpy calculating from measuring point of temperature and relative humidity of the first heat exchanger from 1.0m/s to 4.0m/s with increasing interval 0.5m/s, and the front air velocity. As a result, it is found that cooling capacity of the first heat exchanger showed the best cooling capacity when its frontal air velocity is 2.0 m/s.

• Journal of Environmental Science International
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• v.24 no.5
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• pp.657-670
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• 2015

Visibility and Automatic Weather System(AWS) data near Nakdong river were analyzed to characterize fog formation during 2012-2013. The temperature was lower than its nearby city - Daegu, whereas the humidity was higher than the city. 157 fog events were observed in total during the 2 year period. About 65% of the events occurred in fall (September, October, and November) followed by winter, summer, and spring. 94 early morning fog events of longer than 30 minutes occurred when south westerly wind speed was lower than 2 m/s. During these events, the water temperature was highest followed by soil surface and air temperatures due to the advection of cold and humid air from nearby hill. The observed fog events were categorized using a fog-type classification algorithm, which used surface cooling, wind speed threshold, rate of change of air temperature and dew point temperature. As a result, frontal fog observed 6 times, radiation 4, advection 13, and evaporation 66. The evaporation fog in the study area lasted longer than other reports. It is due to the interactions of cold air drainage flow and warm surface in addition to the evaporation from the water surface. In particular, more than 60% of the evaporation fog events were accompanied with cold air flows over the wet and warm surface. Therefore, it is needed for the identification of the inland fog mechanism to evaluate the impacts of nearby topography and land cover as well as water body.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.246.1-246.1
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• 2010

본 연구는 바이오가스의 에너지효율성을 높이기 위한 연구로서 바이오가스 정제공정과 초저온액화공정을 통하여 액화바이오메탄을 생산하는 바이오가스 고질화기술개발 연구이다. 바이오가스 정제공정은 탈황, 제습, 흡착, 압축, $CO_2/CH_4$ 분리공정으로 구성하고, 초저온액화공정은 열교환기, $CO_2$ 제거설비, 질소냉매 공급공정으로 구성하여 혐기성소화조에서 발생하는 바이오가스($CH_4$ 농도: 60~65%, $H_2S$: 1,500~2,500ppm)를 $200Nm^3/hr$의 유량으로 인입시켜 액화바이오메탄을 생산하였다. 연구결과, 탈황공정에서는 가성소다 세정법을 이용하여 1,500~2,500ppm으로 인입되는 $H_2S$를 100ppm 이하로 제거한 후, 흡착법을 이용하여 $H_2S$를 완전히 제거하였다. 바이오가스에 포화된 수분은 냉각제습과 흡착제습공정을 통해 Dew point $-70{\sim}-90^{\circ}C$까지 제거하여 안정적으로 $CO_2/CH_4$ 분리공정에 인입시켰다. $CO_2/CH_4$ 분리공정은 흡착방식을 적용하여 $CH_4$ 순도가 95% 이상인 바이오메탄을 생산하였으며, 이때 메탄 회수율은 약 87%이였다. $CO_2$가 분리된 바이오메탄은 초저온액화공정을 이용하여 액화바이오메탄으로 전환시켰다. 이때 초저온액화공정은 Reverse Brayton cycle로 구성하였으며, 냉매로는 질소를 사용하였다. 액화바이오메탄의 생산은 바이오메탄을 등엔트로피과정인 단열팽창을 통하여 $-155{\sim}-159^{\circ}C$의 초저온으로 냉각되는 질소냉매와 열교환기에서 열교환시켜 이루어졌으며 그 생산량은 $3.46m^3$/day(1bar, $-161^{\circ}C$)이었다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.429-434
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• 2011

Bulk cargo loaded into ship can be damaged by various kinds reasons. This paper aims to analyze about cargo damage of coil carrier ship due to condensation. Condensation is the formation of liquid drops of water from water vapor. Condensation consists of small drops of water which form when warm water vapour or steam touches a cold surface such as a window. In general, condensation have occurred by temperature difference at large building and ship's tank. It is phenomenon that can occur often to oceangoing vessel moving temperature difference places in similar time. This paper proposes a new method using dehumidification device and fan heater to prevent bulk cargo damage of coil carrier ship from condensation.

• Journal of the Korean Data and Information Science Society
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• v.20 no.6
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• pp.1085-1092
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• 2009

The ozone data is one of the important environmental data for measurement of the atmospheric condition of the country. In this article, the Autoregressive Error (ARE) model and Neural Networks (NN) model have been considered for analyzing the ozone data at the northern part of the Gyeonggi-Do, Paju monitoring site in Korea. In the both ARE model and NN model, seven meteorological variables and four pollution variables are used as the explanatory variables for the ozone data set. The seven meteorological variables are daily maximum temperature, wind speed, relative humidity, rainfall, dew point temperature, steam pressure, and amount of cloud. The four air pollution explanatory variables are Sulfur dioxide ($SO_2$), Nitrogen dioxide ($NO_2$), Cobalt (CO), and Promethium 10 (PM10). The result showed that the NN model is generally better suited for describing the ozone concentration than the ARE model. However, the ARE model will be expected also good when we add the explanatory variables in the model.

• Journal of Conservation Science
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• v.34 no.4
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• pp.283-293
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• 2018

This study involved a comparative analysis of the correlation between meteorological elements and the concentration of airborne fungi(CFU) in relation to biological damage to two temples on piedmonts, which is a cultural heritage building. The work compared Beopjusa temple in Boeun(Chungcheongbuk-do Province) and Seonamsa temple in Suncheon(Jeollanam-do Province). Twelve meteorological elements and the CFU were measured and the Pearson correlation analysis was used to determine the degree of the relationship between them. The results showed that Beopjusa temple had high wind speed, high total horizontal radiation, high evaporation, and large number of days with precipitation. Seonamsa temple had high air temperature, high relative humidity, high dew point temperature, high sea level pressure, high precipitation, and high CFU. The CFU at Beopjusa temple did not have a linear correlation with meteorological elements, but at Seonamsa temple it was highly positive correlated with the number of days with precipitation, relative humidity, and precipitation, and was highly negative correlated with total horizontal radiation. In addition, Beopju and Seonamsa temple had a common linear relationship between factors not affected by the topographical conditions, and had a individual linear correlation between factors affected by the topographical conditions.