• Title/Summary/Keyword: Residence time of air

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A Clinical study on Pediatric Bronchial Asthma (소아천식에 대한 임상적 고찰)

  • Kim, Yun-Hee
    • The Journal of Pediatrics of Korean Medicine
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    • v.16 no.1
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    • pp.133-148
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    • 2002
  • Objective : This study was to investigate more effective oriental medical treatment for Pediatric Bronchial Asthma Method : Aroma therapy and Herbal medicine was given to 28 pediatric bronchial asthma patients(19 males and 9 females) for about 5months from the First, August 1999 The Fifth, January 2002. Results: 1. Demographic factor : The sample consisted of 28 persons among whom 19 were male, 9 were female. The age ranges from 1 year old to 6 year old. Less than 2 year old were 4 and 2-6 year old were 20. 2.Residence : Apartment and villar dwellers were 19(67.9%), Residential street divellers were 9(32.1%). 3.Age distribution at on set : 6(21.4%) fell ill befor 1 year old and 22(78.6%) fell ill after 1 year old 4. The period of illness : 9(32.2%) suffered during 1-3 year and 6(21.4%) suffered during 6 mouth-1year and 6(21.4%) suffered during more than 3 year. 5. Frequency of the symptoms : The symptoms appeared 2-3 times a year in the case of 16(57.2%), one time a year in the case of 1, 4 times a year in the case of 6(21.4%). 6. Concomitance symptoms : All experienced coughing sign, wheezing, 23(82.1%) experienced epistaxis, nose dripping, 13(46.4%) got fever, anorexia. 7. Past history of illness : 16(57.1%) got brochiolitis, brochitis, 12(42.9%) suffered pneumonia, 9(32.1%) had allergic rhinitis. 2 had allergic rhinitis, sinusitis, atopic dermatitis, bronchial asthma, 3 got atopic dermatitis, bronchial asthma and 7 had allergic rhinitis, sinusitis, bronchial asthma, 8. Family disease : In the case of family disease, 21(75%) had allergic dermatitis, 9(42.9%) had bronchial asthma, 8(38.1%) had allergic dermatitis. 9. The symptoms became very severe in the change of season in the case of 13(46.4%) and in the case of 11(39.3%), the change of season made no difference 10. Associated caused of induction symtoms : 28(100%) got sick by common cold, infectional disease, 8(28.6%) got sick by cold food, cold air 11.The kind of therapy : 15(53.6%) got oriental therapy after occidental therapy, 11(39.3%) took only oriental therapy. 12. Improvement degree of each symptoms : In the case of cough and wheeze that are the main symptoms of bronchial asthma, 78.6% and 64.3% of the patients replied < improvement > and in the case of dyspnea, tachypnea 41.7% of the patients replied . In other symptoms, all replied 13. Degree of satisfaction : 19(67.9%) replied , 2(7.1%) replied . Conclusion : Herbal medicine and aroma therapy proved to be a very effective oriental medical treatment for pediatric bronchial asthma.

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A Study on the Characteristics of Small-scale Sewage Treatment Plants in Mountain Area and Operation Plan for Winter Season (산악지역 소규모하수처리시설의 특성 및 동절기 운영방안에 관한 연구)

  • Chae, Heejun;Lee, Jiwon;Gil, Kyungik
    • Journal of Wetlands Research
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    • v.23 no.2
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    • pp.183-188
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    • 2021
  • In the case of small-scale sewage treatment plants, it is reported that the amount of inflow fluctuates and it is difficult to operate the sewage treatment due to the inflow of unknown water due to the aging of sewage pipes. In particular, there are many overall operational problems due to the decrease in water temperature in winter. In this study, the operation status of small-scale sewage treatment facilities located in mountainous areas and water quality changes according to temperature were analyzed. It was found that the concentration of BOD, COD, and SS in effluent water was greatly changed depending on the temperature, and it was found that COD was particularly affected. Accordingly, the water level of the bioreactor was raised by 0.4m in order to temporarily apply measures to lower the water temperature in winter. As a result of comparing and analyzing the results when the bioreactor was covered and operated, a significant improvement effect occurred. In addition, a plan to improve the treatment efficiency of the bioreactor in winter is to extend the residence time of the bioreactor, a plan to expand the bioreactor specification, a new flow control tank and transport it to the outside, and an oxygen-free air diffuser to be used as an aerobic tank in case of an emergency in winter. The improvement plan was suggested. The results of this study are expected to be used as basic data for the operation plan of small-scale sewage treatment facilities in winter.

The Study on the Environmental Factors of Atopic Dermatitis in Oriental-Western Medicine (아토피 피부염의 환경적 요인에 대한 동서의학적 고찰)

  • Park, Sung-gu;Noh, Hyeon-Min;Kweon, So-Hyoun;Jo, Eun-Hee;Jang, Hyun-Chul;Kim, Ho-kyoung;Park, Hi-Joon;Kim, Won-Jeong;Park, Min-Cheol
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.31 no.1
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    • pp.52-70
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    • 2018
  • Objectives : Atopic dermatitis(AD) and environmental factors are closely related, but there is lack of oriental medical examination. So we compared the relationship between AD and various environmental factors in Oriental medicine and Western medicine. Methods : We described the relationship between AD and environmental factors through the latest papers and a review of the oriental medicine literature. Results : The regional diversity of AD incidence implies a close relationship between climate factors and AD, and high altitude and low pH springs also have an effect on AD. Air pollutants from industrialization and urbanization aggravate AD. The increase in indoor residence time and the increase in room temperature and humidity have also increased the sensitization to allergens such as house dust mite. In oriental medicine, wind(風) is one of the environmental factors and is an inflammatory state due to external irritation. Wind-Humidity(風濕) refers to erythematous wetting dermatitis with itching and exudation, Wind-Fever(風熱) refers to acute inflammatory reaction with erythematous papules and plague, and Blood-Weakness(血虛) refers to aggravation and chronicization of inflammation due to persistence of skin barrier impairment. Conclusions : We examined the relationship between AD and various environmental factors. We also described the oriental medical viewpoints of the environmental factors in the occurrence of AD and skin barrier impairment.

Measurement of PM2.5 Concentrations and Comparison of Affecting Factors in Residential Houses in Summer and Autumn (여름과 가을의 주택실내 초미세먼지(PM2.5) 농도 측정 및 영향요인 비교)

  • Dongjun Kim;Gihong Min;Jihun Shin;Youngtae Choe;Kilyoong Choi;Sang Hyo Sim;Wonho Yang
    • Journal of Environmental Health Sciences
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    • v.50 no.1
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    • pp.16-24
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    • 2024
  • Background: Indoor PM2.5 concentrations in residential houses can be affected by various factors depending on the season. This is because not only do the climate characteristics depend on the season, but the activity patterns of occupants are also different. Objectives: The purpose of this study is to compare factors affecting indoor PM2.5 concentrations in apartments and detached houses in Daegu according to seasonal changes. Methods: This study included 20 households in Daegu, South Korea. The study was conducted during the summer (from July 10 to August 10, 2023) and the autumn (from September 11 to October 9, 2023). A sensor-based instrument for PM2.5 levels was installed in the living room of each residence, and measurements were taken continuously for 24 hours at intervals of one minute during the measurement period. Based on the air quality monitoring system data in Daegu, outdoor PM2.5 concentrations were estimated using ordinary kriging (OK) in Python. In addition, the indoor activities of the occupants were investigated using a time-activity pattern diary. The affecting factors of indoor PM2.5 concentration were analyzed using multiple regression analysis. Results: Indoor and outdoor PM2.5 concentrations of the residences during summer were 15.27±11.09 ㎍/m3 and 11.52±7.56 ㎍/m3, respectively. Indoor and outdoor PM2.5 concentrations during autumn were 13.82±9.61 ㎍/m3 and 9.57±5.50 ㎍/m3, respectively. The PM2.5 concentrations were higher in summer compared to autumn both indoors and outdoors. The primary factor affecting indoor PM2.5 concentration in summer was occupant activity. On the other hand, during the autumn season, the primary affecting factor was outdoor PM2.5 concentration. Conclusions: Indoor PM2.5 concentration in residential houses is affected by occupant activity such as the inflow of outdoor PM2.5 concentration, cooking, and cleaning, as found in previous studies. However, it was revealed that there were differences depending on the season.

Estimation of Multimedia Environmental Distribution for Benzoyl peroxide Using EQC Model (EQC 모델을 이용한 벤조일 퍼록사이드의 다매체 환경거동 예측)

  • Kim, Mi-Kyoung;Bae, Hee-Kyung;Song, Sang-Hwan;Koo, Hyun-Ju;Kim, Hyun-Mi;Choi, Kwang-Soo;Jeon, Sung-Hwan;Lee, Moon-Soon
    • Journal of Korean Society of Environmental Engineers
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    • v.27 no.10
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    • pp.1090-1098
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    • 2005
  • Benzoyl peroxide is very toxic to aquatic organisms but environmental concentration or exposure effects were not studied. Distribution of the chemical among multimedia environment was estimated using EQC(Equilibrium Criterion) model based on the physical-chemical properties to evaluate the risk of benzoyl peroxide in environment. Level I describes a situation that 100,000 kg of benzoyl peroxide is emitted into the environment which is equilibrium and steady-state without degradation and advection condition. Level II describes a situation that a constant rate of 1,000kg/h of benzoyl peroxide is continuously discharged into the environment which is equilibrium and steady-state with degradation and advection condition. Level III describes a situation that 1,000 kg/h of benzoyl peroxide is continuously introduced in each air, water, soil, and sediment compartment which are non-equilibrium and steady-state with degradation, advection, and inter-media transfer condition. In Level I and II calculations the chemical was distributed to soil(68.3%) and water(28.7%). In Level III calculation it was primarily distributed to soil(99.9%) and overall residence time was estimated to be 3.4 years. Benzoyl peroxide can be persistent in environment.

Characteristics of a Plasma-Dump Combustor for VOC Destruction (VOC 분해 플라즈마-덤프 연소기 특성)

  • Kim, Eun Hyuk;Chun, Young Nam
    • Journal of Korean Society of Environmental Engineers
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    • v.37 no.8
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    • pp.492-497
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    • 2015
  • VOCs (Volatile Organic Compounds) are generally generated in the painting process, or at the company and laundry where use organic solvents. The VOCs consist of various hydrocarbons and has low calorific value due to its dilution with atmospheric air. Therefore, the VOCs are difficult to burn by a conventional fuel combustor. In this study, a novel plasma dump combustor was proposed for the treatment of low calorific VOC gases. This combustor was designed a combination of the characteristics in a plasma burner, a dump combustor and a 3D matrix burner. The combustor has good structure for maintaining enough residence time and reaction temperature for stable flame formation and VOC destruction. For investigating the performance characteristics of the plasma dump combustor, an experiment was achieved for VOC feed rate, VOC injector position, etc. Toluene was used as a surrogate of VOC. The novel combustor gave better performance than a conventional combustor, showing that VOC destruction rate and energy efficiency were 89.64% and 12.27 kg/kWh respectively, at feeding rate of 450 L/min of VOC of 3,000 ppm of toluene concentration.

Numerical Analysis for Improvement of Windshield Defrost Performance of Electric Vehicle (전기자동차 전면유리 제상성능 개선을 위한 전산수치 해석)

  • Kim, Hyun-Il;Kim, Jae-Sung;Kim, Myung-Il;Lee, Jae Yeol
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.5
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    • pp.477-484
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    • 2019
  • As the residence time in the vehicle increases, the passenger desires a pleasant and stable riding environment in addition to the high driving performance of the vehicle. The windshield defrosting performance is one of the performance requirements that is essential for driver's safe driving. In order to improve the defrosting performance of the windshield of a vehicle, relevant elements such as the shape of the defrost nozzle should be appropriately designed. In this paper, CFD based numerical analysis is conducted to improve defrost performance of small electric vehicles. The defrost performance analysis was performed by changing the angle of the defrost nozzle and the guide vane that spray hot air to the windshield of the vehicle. Numerical simulation results show that the defrosting performance is best when the defrost nozzle angle is $70^{\circ}$ and the guide vane installation angle is $60^{\circ}$. Based on the analytical results, the defrosting experiment was performed by fabricating the defrost nozzle and the guide vane. As a result of the experiment, it is confirmed that the frost of windshield is removed by 80% within 20 minutes, and it is judged that the defrost performance satisfying the FVMSS 103 specification is secured.

Advanced Wastewater Treatment of Low Concentration Ammonia Using the Immobilized Nitrifier Consortium (고정화 질화세균을 이용한 저농도 암모니아 폐수의 고도처리)

  • Lee, Jung-Hoon;Kim, Byong-Jin;Kim, Yong-Ha;Yi, Gyeong-Beom;Lim, Jun-Heok;Cheon, Jae-Kee;Suh, Kuen-Hack
    • Korean Chemical Engineering Research
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    • v.40 no.6
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    • pp.763-768
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    • 2002
  • This study was performed in the airlift bioreactor using the nitrifier consortium entrapped in polyvinyl alcohol(PVA) for removing low concentration total ammonia nitrogen(TAN). At the superficial air velocity of 0.83 cm/sec, TAN removal rate and removal efficiency was $316.6{\pm}7.2g/m^3{\cdot}day$ and $92.8{\pm}2.2%$ respectively. Removal rate was continuously increased with decreasing hydraulic residence time(HRT) from 0.5 hr to 0.05 hr, whereas removal efficiency decreased with decreasing HRT. The optimum temperature for nitrification was $30^{\circ}C$ at which removal efficiency was $95.5{\pm}1.5%$. Nitrification was effectively performed at low temperature, $10^{\circ}C$. In the pH range from 7 to 9 in the bioreactor, removal rate and removal efficiency was $310{\pm}10g/m^3{\cdot}day$ and $94{\pm}3%$ respectively.

Hydrochemistry and Noble Gas Origin of Various Hot Spring Waters from the Eastern area in South Korea (동해안지역 온천유형별 수리화학적 특성 및 영족기체 기원)

  • Jeong, Chan-Ho;Nagao, Keisuke;Kim, Kyu-Han;Choi, Hun-Kong;Sumino, Hirochika;Park, Ji-Sun;Park, Chung-Hwa;Lee, Jong-Ig;Hur, Soon-Do
    • Journal of Soil and Groundwater Environment
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    • v.13 no.1
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    • pp.1-12
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    • 2008
  • The purpose of this study is to characterize the hydrogeochemical characteristics of hot spring waters and to interpret the source of noble gases and the geochemical environment of the hot spring waters distributed along the eastern area of the Korean peninsula. For this purpose, We carried out the chemical, stable isotopic and noble gas isotopic analyses for eleven hot spring water and fourteen hot spring gas samples collected from six hot spring sites. The hot spring waters except the Osaek hot spring water show the pH range of 7.0 to 9.1. However, the Osaek $CO_2$-rich hot spring water shows a weak acid of pH 5.7. The temperature of hot spring waters in the study area ranges from $25.7^{\circ}C$ to $68.3^{\circ}C$. Electrical conductivity of hot spring waters varies widely from 202 to $7,130{\mu}S/cm$. High electrical conductivity (av., $3,890{\mu}S/sm$) by high Na and Cl contents of the Haeundae and the Dongrae hot spring waters indicates that the hot spring waters were mixed with seawater in the subsurface thermal system. The type of hot springs in the viewpoint of dissolved components can be grouped into three types: (1) alkaline Na-$HCO_3$ type including sulfur gas of the Osaek, Baekam, Dukgu and Chuksan hot springs, and (2) saline Na-Cl type of the Haeundae and Dongrae hot springs, and (3) weak acid $CO_2$-rich Na-$HCO_3$ type of Osaek hot spring. Tritium ratios of the Haeundae and the Dongrae hot springs indicate different residence time in their aquifers of older water of $0.0{\sim}0.3$ TU and younger water of $5.9{\sim}8.8$ TU. The ${\delta}^{18}O$ and ${\delta}D$ values of hot spring waters indicate that they originate from the meteoric water, and that the values also reflect a latitude effect according to their locations. $^3He/^4He$ ratios of the hot spring waters except Osaek $CO_2$-rich hot spring water range from $0.1{\times}10^{-6}$ to $1.1{\times}10^{-6}$ which are plotted above the mixing line between air and crustal components. It means that the He gas in hot spring waters was originated mainly from atmosphere and crust sources, and partly from mantle sources. The Osaek $CO_2$-rich hot spring water shows $3.3{\times}10^{-6}$ in $^3He/^4He$ ratio that is 2.4 times higher than those of atmosphere. It provides clearly a helium source from the deep mantle. $^{40}Ar/^{36}Ar$ ratios of hot spring water are in the range of an atmosphere source.