• Journal of Soil and Groundwater Environment
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• v.12 no.2
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• pp.65-71
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• 2007

This study has been focused on an application of microwave pre-treatment of soil contaminated with volatile organic chemicals, and BTEX(benzene, toluene, ethylene, xylene). Microwave experiments were carried out under different power conditions (2 kW, 4 kW) using different moisture contents and BTEX concentration. According to these results of this study, the most BTEX removal efficiency was with 20% moisture contents regardless of electric power. The result show that 2kW was determined to the optimum electric power at $10{\sim}30%$ moisture contents, but the optimum power was 4 kW at 50% of moisture content.

• Journal of Animal Environmental Science
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• v.2 no.1
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• pp.79-86
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• 1996

Solid/Liquid(S/L) separation is crucial for biological treatment of animal wastewater. Liquid portion from S/L separation has less BOD-load and proper post-strip treatment can be obtained. Screen or declined sieve was normally used to separate the solid parts. For better separating efficiency a vibration and a cylindrical separator were constructed and tested. The results are summarized as follows; Solids removal efficiency and moisture content of separated solid were 15~26% and 85~88%, respectively for the vibration separator. for the cylindrical separator, solid removal efficiency and moisture content of solid were 16~39% and 86~89%, respectively. The greatest amount of drymatter was obtained when operating vibration separator with 10$^{\circ}$ inclination and 100% vibrating power. For the cylindrical separator maximum efficiency was obtained with 40 rpm and 19$^{\circ}$ inclination. The vibration and the cylindrical separator have shown 21% and 26% in BOD removal, respectively. These two types of separator were proved to be applicable methods for animal wastewater separation.

• Journal of the Korean Wood Science and Technology
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• v.44 no.2
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• pp.283-293
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• 2016

Owing to an increase in the air tightness of recent buildings, the natural ventilation rate was significantly lowered and the removal of accumulated moisture became difficult in these buildings. The hygrothermal performance of these buildings should be carefully considered to provide comfortable indoor environment by removing the moisture condensation risk and the mold growth potential. In this study, hygrothermal performance of two selected wall structures was investigated based on WUFI simulation program. The results displayed that the indoor temperature had impact on the moisture accumulation in the insulation layer for both modeled walls, showing that lower indoor temperature resulted in higher moisture accumulation, especially in the wood frame structure. Also, the yearly moisture accumulation profile exhibited a downward shift throughout the year by adding a vapour retarder with a lower sd-value. In addition, both of the two walls have condensation risk in winter, due to low temperature level. The wood frame structure has a bigger fluctuation and higher condensation risk than the concrete structure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.4
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• pp.347-357
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• 2024

Oxide semiconductor gas sensors are widely used for detecting toxic, explosive, and flammable gases due to their simple structure, cost-effectiveness, and potential integration into compact devices. However, their reliable gas detection is hindered by a longstanding issue known as humidity dependence, wherein the sensor resistance and gas response change significantly in the presence of moisture. This problem has persisted since the inception of oxide semiconductor gas sensors in the 1960s. This paper explores the root causes of humidity dependence in oxide semiconductor gas sensors and presents strategies to address this challenge. Mitigation strategies include functionalizing the gas-sensing material with noble metal/transition metal oxides and rare-earth/rare-earth oxides, as well as implementing a moisture barrier layer to prevent moisture diffusion into the gas-sensing film. Developing oxide semiconductor gas sensors immune to humidity dependence is expected to yield substantial socioeconomic benefits by enabling medical diagnosis, food quality assessment, environmental monitoring, and sensor network establishment.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.106-111
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• 2012

Drying characteristic of high moisture coal using a 5 kg/hr bench scale flash dryer was investigated. Moisture content and heating value of raw coal as received basis were 29.74 wt% and 4,270 kcal/kg, respectively. Gas inlet temperature and gas inlet flow rate were $400{\sim}600^{\circ}C$ and 10~20 m/sec, respectively. The raw coal was ground and classified to the particle size range of $100{\sim}2,000{\mu}m$. The moisture removal rate of raw coal was dramatically increased with increasing gas inlet temperature and decreasing gas inlet flow rate. The heating value of dried coal was increased to 5,100~5,900 kcal/kg. To examine the chemical change on the surface of high moisture coal during flash drying process, FT-IR spectral analysis was carried out. As a result, major changes in hydroxyl, carboxyl and carbonyl peak was confirmed.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1995.05a
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• pp.101-112
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• 1995

In order to improve the recovery efficiency of heavy water vapour from the atmosphere inside a reactor building, and to recover and upgrade the heavy water which escape, special treatments, such as reducing the ingress of light water vapour, are studied in the design of the CANDU reactor systems. This is considered in controlled method of the humidity over drawing fresh air through a desiccant dehumidifier which dries the air by absorption. Comparing with the moisture loads between summer and winter operations, the moisture removal rates are calculated. Those are proportional to the difference between the controlled space and the surrounding environment Installation of a new dehumidifier will be able to reduce the moisture loads from the cooling systems, improving overall system efficiency and saving operating costs.

• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.196.2-196
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• 2002

• Asian Journal of Atmospheric Environment
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• v.4 no.2
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• pp.63-71
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• 2010

The removal characteristics for aromatic and aliphatic VOCs by electron beam (EB) were discussed in terms of several removal variables such as initial VOC concentration, absorbed dose, background gas, moisture content, reactor material and inlet temperature. It was reviewed that only reactor material was an independent variable among the potential control factors concerned. It was also suggested that main mechanism by EB should be radical reaction for the VOC removal rather than that by primary electrons. It was discussed that the removal efficiency of benzene was lower than that of hexane due to a closed benzene ring. In the case of aromatic VOCs, it was observed that the decomposition of the VOCs with more functional groups attached on the benzene ring was much easier than those with less ones. As for aliphatic VOCs, it was also implied that the longer carbon chain was, the higher the removal efficiency became. An EB-catalyst hybrid system was discussed as an alternative way to remove VOCs more effectively than EB-only system due to much less by-products. This hybrid included supporting materials such as cordierite, Y-zeolite, and $\gamma$-alumina.

• Journal of Drive and Control
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• v.16 no.2
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• pp.51-58
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• 2019

In this study, flow analysis and dehumidification experiment were conducted on hollow fiber membrane module to determine the dehumidification characteristics of its various configurations. A quantitative analysis of the CFD for four different models with a temperature of $30^{\circ}C$ and 30%RH inlet humidity was conducted. Each model has different shape parameters i.e. the number of hollow fiber membranes and the presence or absence of baffles. After comparison between the flow analysis results and dehumidification experiment results, the percentage error was found to be approximately 2%. The moisture removal rate for each model was calculated using flow analysis data. It was found that the moisture removal rate of refined model with three baffles and eight hollow fiber membranes was highest among the four modeled modules of hollow fiber membrane one, i.e. about 60%.

• Journal of Korean society of Dental Hygiene
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• v.4 no.2
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• pp.277-291
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• 2004

The purpose of this study is to analyze the dental hygienists' overall performance in operative restoration and the clinical performance in operative restoration according to dental hygienists' career and to provide basic data for establishing the appropriate range of dental hygienists' work. Subjects of this study are 339 dental hygienists working at dental clinic and hospital nationwide, selected by their working place, career, type of clinic, and location of clinical institution. The distribution of people who responded to the survey shows that 81 belong to beginner level(less than 2 years since entering clinic), 115 intermediate level(2 to 3 years since entering clinic), 81 higher level(4 to 5 years since entering clinic) and 62 advanced level(more than 6 years since their entering clinic). In terms of the types of clinical institution, 178 belong to dental clinics and 161 belong to dental hospitals. The survey used in this study are focused on perception about clinical performance in operative dentistry and adequacy of the work. Operative dentistry consists of operative restoration and endodontic therapy. The operative restoration consists of 15 categories such as patient welcoming, examination and diagnosis, planning of treatment, anesthesia, control of moisture, cavity preparation, pulp protection, matrix band application, amalgam filling, resin filling, glass ionomer cement filling, abrasive strip removal, rubber dam removal, bite check and polishing, patient education, and arrangement. The reliability was Cronbach's Alpha .9453. SPSS 10.0 for Windows was used to analyze the responses. One way ANOVA was utilized to verify the differences in the dental hygienists' job performance in operative restoration and their job performance according to career. When significant difference was found. Duncan multi comparison post hoc was done. To sum up the results of this study, patient welcoming look the first place in the operative restoration. It was followed by patient education, examination and diagnosis, introducing treatment plan, resin filling, glass ionomer cement filling, amalgam filling, bite check and polishing, anesthesia, pulp protection, control of moisture, abrasive strip removal, cavity preparation, matrix band application, rubber dam removal, and anesthesia. In terms of the clinical performance by career, there were significant differences in 19 activities such as medical eraluation, oral examination, patient charting, intra oral readio graphs, firm developing fixing mounting, curing light gun, education of attention content after operation. Based on the results of this study, the specific range of operative restoration for dental hygienists should be focused on providing basic data for dentists' diagnosis, alleviation of fear and aching accompanied by injection and anesthesia, data providing for dentists' decision of anesthesia degree, and maximization of control of moisture.