• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.10
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• pp.530-537
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• 2017

Scales generated inside pipes cause negative effects on heat transfer performance, pressure loss and flow rate due to increased thermal resistance and reduced flow cross-sectional area. If these scales are not prevented or eliminated, thermal-fluid performance of the facilities can be deteriorated, or in extreme cases, accidents such as explosion due to overheating can occur. There are two ways to remove the scales, physically and chemically. Removing the scales physically needs specific machines which are expensive, and removing them chemically may provoke corrosion or shorten the age of the facilities. In this study, an eco-friendly pipe scale cleaner using natural organic acid is developed by applying the concept of a limestone cave generation. The manufactured scale cleaner is applied to remove the scales in industrial, water heating and urinal pipes. The results show that this cleaner removes scales more effectively and safely compared to existing scale treatments. Scale removal efficiencies of this work is 1.2~10.7 times for industrial pipes and 1.8~15.5 times for boiler water heating pipes higher than those of conventional cleaners.

• Journal of Environmental Science International
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• v.16 no.7
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• pp.785-791
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• 2007

The current study evaluated the technical feasibility of the application of titanium dioxide ($TiO_{2}$) photo-catalytic air cleaners for the disinfection of bioaerosols present in indoor air. The evaluation included both laboratory and field tests and the tests of hydraulic diameter (HD) and lamp type (LT). Disinfection efficiency of photocatalytic oxidation (PCO) technique was estimated by survival ratio of bacteria or fungi calculated from the number of viable cells which form colonies on the nutrient agar plates. It was suggested that the reactor coating with $TiO_{2}$ did not enhance the adsorption of bioaerosols, and that the UV irradiation has certain extent of disinfection efficiency. The disinfection efficiency increased as HD decreased, most likely due to the decrease in the light intensity since the distance of the catalyst from the light source increased when increasing the HD. It was further suggested that the mass transfer effects were not as important as the light intensity effects on the PCO disinfection efficiency of bioaerosols. Germicidal lamp was superior to the black lamp for the disinfection of airborne bacteria and fungi, which is supported by the finding that the disinfection efficiencies were higher when the germicidal lamp was used compared to the black lamp in the laboratory test. These findings, combined with operational attributes such as a low pressure drop across the reactor and ambient temperature operation, can make the PCO reactor a possible tool in the effort to improve indoor bioaerosol levels.

• The Journal of Pediatrics of Korean Medicine
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• v.24 no.2
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• pp.112-125
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• 2010

Objectives The purpose of this study is to find the relationships between the allergy and weakness in children in Seong-Dong district. Methods 802 day care centers children were participated for survey on allergic disease, risk factors, and weakness. From the result, we analyzed the relationships between the aforementioned factors. Results 1. 802 children were participated for the survey. We eliminated survey answers with unclear answers, and selected 792 survey sheets as our final subject of study. The age of majority of subjects(720 children) were between one to six years old, and the others were under the age of one and over seven. 2. The prevalence rate of asthma in a lifetime was 6.69%, allergic rhinitis was 14.87%, atopic dermatitis was 28.82%, allergic conjunctivitis was 6.29%, food allergies was 9.58%, and drug allergies was 1.4%. In 2009, the prevalence rate of allergies during treatments is 6.69% for asthma, 13.41% for allergic rhinitis, 13.64% for atopic dermatitis, 4.13% for allergic conjunctivitis, 5.23% for food allergies, 0.96% for drug allergies. 3. The significant risk factors were types of dwelling, pet with fur, dirty environments without vacuum cleaners, the numbers of times bed covers were washed, frequency of air ventilation, changes in body after moving, family history. 4. The distribution of the number of children with weakness within the five visceras were respiratory weakness, digestive weakness, psychoneurologic weakness, neuromotor weakness, and urogenital weakness in the order of most to the least. More specifically, children who only has respiratory weakness were the majority, while children who have respiratory and digestive weaknesses, children who have respiratory, digestive, and psychoneurologic weaknesses, children who have respiratory and psychoneurologic were followed. 5. With the exception of children with urogenital weakness, Most of the children with respiratory weakness, digestive weakness, psychoneurologic weakness, and neuromotor weakness had been treated for allergies in 2009, while children who were diagnosed with allergic diseases at least once in their lifetime most likely had weak respiratory, digestive or psychoneurologic systems. Conclusions The results of this study showed that there was a correlation between children with weak viscera and children with allergic diseases. However, further research would be necessary.

• Parasites, Hosts and Diseases
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• v.35 no.1
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• pp.9-17
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• 1997

During the period of 1933-1994, house dusts were collected from 65 homes at 10 different localities by operating electric vacuum cleaners. House dust mites were isolated from 10 g dust by applying the modified wet sieving method. Total 7,257 mites were collected and 23 species were identified. Among them, Demctophqgoines loyinaf (DF) was predominant (65. Soy) of the total) , followed by D. pteronvssinus (DP) (20.6%) and Tyrophagus nutrescentios (TP) (6.5%) . Rhizoglvphur robini, Sancqsscnin phvIlophogiann, Cheyletus trcussarti and Scheloribates latipes were the first findings from Korea. DF was predominant in Seoul (66.8%), Kwangju (63.6%), inland of Pusan (79.6%1, Inchon (96.5%), Taejon (83.9%), Chouju (87.15) and Chongiu (95.2%), whereas DP was predominant in Yongkwang-ub (72.5%) and Yongdo (island) of Pusan (64.9%), and TP in Chunchon (38.2%) The localities where DP and TP were predominant showed higher relative humidity in air (> 73% RH) . Among 62 study homes, DF, DP and TP were found in 24.6% of the homes, co-habitat of two species in 48.1% and one species in 27.3%. DF was predominant in 63.5% of the homes studied, DP in 29.6% and TP in 6.9%. In 10 g of the house dust, less than 99 mites were found in 49 homes (70.0%), 100-499 mites in 11 homes (15.7%), 500-999 mites in 3 homes (4.3%) and more than 1,000 mites in 2 homes (2.9%). No mite was found in 5 homes (7.1%). In order to evaluate environmental factors affecting the population density of house dust mites, house type, age of house construction, size of the house, number of the family and frequency of the cleaning were compared with the number of mites, and none of the above factors were statistically correlated with the mite density.