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공기 중 유기용제 농도수준이 방독마스크 정화통의 활성탄 흡착용량에 미치는 영향
박두용,Park, Doo-Yong 한국환경보건학회 2011 한국환경보건학회지 Vol.37 No.1
The adsorption capacity of charcoal is a function of the airborne concentration of the target chemical. To evaluate the adsorption capacity of charcoal packed in the cartridges of air purifying respirators, breakthrough tests were conducted with carbon tetrachloride for three commercial cartridges (3M models #7251, #6000 and AX) at 25, 50, 100, 250 and 500 ppm. Adsorption capacities were calculated using a mass transfer balance equation derived from the curve fitting to the breakthrough curves obtained experimentally. Carbon micropore volumes were estimated by iteration to fit the Dubinin/Radushkevich (D/R) adsorption isotherm. They were 0.6566, 0.5727 and 0.3087 g/cc for #7251, #6000 and the AX cartridge, respectively. Above 100 ppm (at high challenge concentrations), #7251 and #6000 showed higher adsorption capacities. However, as the challenge concentration decreased, the adsorption capacities of #7251 and #6000 sharply dropped. On the other hand, the adsorption capacity of the AX cartridge showed little change with the decrease of the challenge concentration. Thus, the AX showed a higher adsorption capacity than #7251 and #6000 at the 5-50 ppm level. It is concluded that service-life tests of cartridges and adsorption capacity tests of charcoal should be conducted at challenge concentration levels reflecting actual working environmental conditions. Alternatively, it is recommended to use the D/R adsorption isotherm to extrapolate adsorption capacity at low concentration levels from the high concentration levels at which breakthrough tests are conducted, at a minimum of two different concentration levels.
계절 ARIMA모형을 이용한 스포츠센터의 여성회원객에 대한 수요예측
설민신(Min Sin Sul),박두용(Doo Yong Park) 한국여성체육학회 2011 한국여성체육학회지 Vol.25 No.3
As the number of female participants increases, the necessity of practical and scientific demand prediction of female sport participants is rising. In order to predict the demand, we performed a times-series analysis for female swimming, aerobic and yoga program in a sport center located in Yong-in during the period of October, 2004 - July, 2011. We have selected the ARIMA(1, 1, 0) model through diagnosing model specification - parametric estimation - model suitability diagnosis and analyzed through SPSS 18.0 version. According to our research, the number of female participant has decreased gradually from October to February and has increased after February as summer season approaches.
석면슬레이트 제조 및 석면방직사업장 근로자의 석면분진폭로
朴枓用(Doo Yong Park),白南園(Nam Won Paik) 한국환경보건학회 1988 한국환경보건학회지 Vol.14 No.2
Two asbestos s1ate manufacturing and seven asbestos textile p1ants in Korea were surveyed from May 20 to Ju1y 2, 1987. The purposes of this study were to evaluate 1) worker exposure to asbestos, 2) compliance to the standards and 3) the efficiency of existing loca1 exhaust systems. Sixty-two persona1 samples and eighty-three area samp1es were col1ected and analyzed using“ NIOSH 7400 method. Resu1ts of this study were as fol1ows. 1. The asbesots exposure concentrations in asbestos textile plants were 1.3 - 14.3 fibers/cc(geometric mean(GM), 4.4 fibers/cc). 2. Worker exposure level to asbestos fiber in asbestos slate manufacturing industry was 0.21 fibers/cc during wet processing, which is below the Korean Standard of 2 fibers/cc. 3. Most local e앙laust systems installed in asbestos textile plants were inadequately designed. 4. : olinety-six percent of the 145 samples exceeded the U.S.Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) of 0.2 fibers/cc and forty-nine percent of the samp1es exceeded the Korean Standard of 2 fibers/cc.