터널건설공사시 발생분진의 입경특성

류장진,장재길,이병규,정시정,김성진,김광종 한국산업위생학회 2003 한국산업보건학회지 Vol.13 No.2

In tunnel construction work. major dust-generating activities are blasting rock, rock drilling and transport operations. The aim of this study was to find the characterisitic of particle size of dusts which were generated during road tunnel construction work using the New Austrian Tunneling Method(NATM). An 8-stage personal cascade impactor was used for particle size-selective sampling by area sampilng method. Paired samples for total(closed-face 37-mm cassette holder)and respirable(10 mm nylon cyclone) dust were taken to compare with the results of cascade impactor at the same location where cascade impactor samples were taken, The geometric mean of mass median aerodynamic diameter(MMAD) of dust is 3.9(GSD=4.3). This is quite similar to 50% cut size(4.0 ) for respirable mass fraction defined in the ACGIH TLV. The mass fraction of inhalable, thoracic, and respirable particulate defined at ACGIH TLV are 84.0%, 67.2% and 43.1%, respectively. The arithmetic mean ratio of inhalable particulate mass to respirable particulate mass is 2.04 for paired sample, 1.95 for cascade impamtor sample, which showed much lower than those of other construction tasks. We conclude that the dust generated during road tunnel excavation has about 50% respirable fraction in inhalable particulate mass.

스테인레스 강에 대한 플럭스 코어드 아크 용접공정에서의 흄 발생량 및 입자 크기 분포에 관한 연구

윤충식(Chung Sik Yoon),백남원(Nam Won Paik) 한국환경보건학회 1999 한국환경보건학회지 Vol.25 No.2

A study was conducted for the effects of currents and voltages on the fume generation rates at CO₂ flux cored arc welding on stainless steel. Fume size distributions were also studied. Experiments were run in well designed welding fume box. Six types of flux cored wires were used and three levels of currents and voltages were given. Fume generation rates of domestic flux cored wires are 0.2-0.3 g/min at the lowest input energy and 0.81~0.85 g/min at the highest input energy tested. Fume generation rates could be related to the welding current with secondary power function and to the input energy with primary power function. Flux cored wires, when melted by arc, transfered into the deposited metal(82 ~92% ), slag(9~13% ), spatter(l~6% ), and fume(0.5~1 % ) respectively. Fulx cored welding fumes are all respirable particulate mass.

桑葉 Ethyl Acetate 추출물이 카드뮴의 흡입독성에 미치는 영향

정재열,송용선,이기남 대한동의병리학회 2003 동의생리병리학회지 Vol.17 No.3

For the experiment of the effects between cadmium aerosol inhalation toxicity and ethyl acetate extracts of Folium Mori, 4 inhalation exposure groups of rat were exposed to cadmium aerosol in air by whole-body inhalation exposure for 6 hours/day, 5 days/week, and 4 weeks. Cadmium concentration in the air was 0.96㎎/㎥ and mass median diameter (MMD) was 2.48㎛ with 1.85 of geometric standard deviation(GSD). Intraperitoneal injections of ethyl acetate extracts of Folium Mori to inhalation exposure groups were performed for 4 weeks and the results were as follows: The highest body weight gain for 4 weeks and food intake per day were 159.29/4 weeks in treated group Ⅲ and 18.45g/day in treated group Ⅰ, respectively. The highest lung and liver weight were 1.31g in treated group Ⅰ and 9.42g in treated group Ⅲ, respectively. The highest kidney weight was 2.21g from treated group Ⅰ. The lowest cadmium content in lung was 86.39㎍/g from treated group Ⅲ and the lowest cadmium concentration in blood was 2.72㎍/㎗ from treated group Ⅱ. Cadmium concentrations of 22.09㎍/g in liver and 24.82㎍/g in kidney were the lowest from inhalation exposure group Ⅰ and Ⅲ, respectively. For weekly cadmium concentration in urine, the value of the fourth week from treated group Ⅲ was the highest, 1.35㎍/㎖. For weekly cadmium concentration in feces, the values of the second and fourth week from treated group Ⅰ were the highest, 1.11㎍/g. The highest metallothionein concentration in lung was 31.85㎍/g from treated group Ⅲ and the highest metallothionein concentration in liver was 205.77㎍/g from treated group Ⅲ. The highest metallothionein concentration in kidney was 206.55㎍/g from treated group Ⅲ. The highest Hct and Hb values were 38.26% and 11.63g/㎗ from treated group Ⅲ, respectively. The highest RBC and WBC values were 7.68×106/㎣ and 9.85×10^3/㎣ from treated group Ⅰ, respectively.

황사현상시에 성남시에 포집한 분진한 입경분포 및 중금속 농도

권우택,유영식 서울보건대학 1996 서울보건대학 부설 한국보건과학연구소 논문집 Vol.3 No.1

The heavy metal concentrations and size distribution are the most important parameters influencing among the way in which airborne suspended particulate matters interact with the human respiratory system. Airborne suspended particulate matters were collected on a glass fiber filter from April to May 1996 using high-volume air sampler and Andersen sampler at Sungnam City. And those of Yellow Sand Phenomena period were investigated to find out the characteristics between normal and Yellow Sand Phenomena period. The results could be summerized as follows : 1. The Yellow Sand Phenomena period of TSP concentration was 264.7㎍/㎥ and normal period of TSP concentration was 117.5㎍/㎥. 2. The Yellow Sand Phenomena period ratio of PM-10 to TSP(PM-10/TSP) was 19.6% and normal period of PM-10 to TSP(PM-10/TSP) was 27.9%. 3. During the period of Yellow Sand Phenomena, the ratio of coarse particles to TSP was 70.7%. 4. The heavy metals were analyzed as follows showing in order of high concentration: Fe>Si> Na>Zn> Mn> Pb>Cu> Ni>Cd. 5. The mass median diameter(MMD) of Ni, Cd, Zn, Pb and Cu were 0.73, 1.07, 1.67, 1.77 and 1.79㎛, respectively, Na, Si, Fe and Mn were 2.66,4.87,5.12 and 5.84㎛, respectively. 6. Those with MMD smaller than about 2㎛ are commonly associated with anthropogenic processes, in contrast, MMD greater than 2㎛ are emitted mainly by natural processes.

사이펀 노즐의 오리피스 직경변화에 따른 분무특성에 관한 연구

고동국 한국기계기술학회 2023 한국기계기술학회지 Vol.25 No.6

In this study, we examined the effect of orifice diameter on atomization performance such as SMD(Sauter Mean Diameter), MMD(Mass median diameter), particle size distribution, spray distance, and spray angle when water was sprayed through a siphon nozzle. In addition, the behavior characteristics of spray were analyzed using the CFD(Computational Fluid Dynamics) commercial program. In the downstream direction of the flow, the dispersion and diffusion power of the droplets increased, greatly improving atomization performance. The spray spread in the radial direction when the jet velocity of water increased. As a result, atomization performance improved as the jet velocity increased.

흡입독성 연구를 위한 2730ppm 납 네뷸라이징 용액에서 발생된 에어로졸의 입경분석

정재열,강성호,김삼태,이은경,송용선,이기남 대한동의생리학회,대한동의병리학회 2003 동의생리병리학회지 Vol.17 No.2

Ultrasonic nebulizer with the application of new engineering methodology and the design of electronic circuit was made for lead inhalation toxicology study and 2730ppm lead nebulizing solution was used to generate lead aerosol. After modification of source and inlet temperatures, the results of particle size analysis for lead aerosol were as following. The highest particle counting for source temperature 20˚c was 39933.66 in inlet temperature 100˚C and particle diameter 0.75㎛. The highest particle counting for source temperature 50˚C was 39992.71 in inlet temperature 250˚C and particle diameter 0.75㎛. The highest particle counting for source temperature 70˚C was 37569.55 in inlet temperature 50˚C and particle diameter 0.75㎛. The ranges of geometric mean diameter(GMD) were 0.754-0.784㎛ for source temperature 20˚C, 0.758-0.852㎛ for source temperature 50˚C, and 0.869-1.060㎛ for source temperature 70˚C. The smallest GMD was 0.754㎛ in source temperature 20˚C and inlet temperature 20˚C, and the largest GMD was 1.060㎛ in source temperature 70˚C and inlet temperature 250˚C. The ranges of geometric standard deviation(GSD) were 1.730-1.782 for source temperature 20˚c, 1.734-1.894 for source temperature 50˚C, and 1.921-2.148 for source temperature 70˚C. The lowest GSD was 1.730 in source temperature 20˚c and inlet temperature 20˚C, and the highest GSD was 2.148 in source temperature 70˚C and inlet temperature 250˚C. Lead aerosol generated in this study was polydisperse. The ranges of mass median diameter(MMD) were 1.856-2.133㎛ for source temperature 20˚C, 1.877-2.894㎛ for source temperature 50˚C, and 3.120-6.1091m for source temperature 70˚C. The smallest MMD was 1.856㎛ in source temperature 20˚C and inlet temperature 20˚C, and the largest MMD was 6.109㎛ in source temperature 70˚C and inlet temperature 250˚C. Slight increases for GMD, GSD, and MMD values were observed with same source temperature and increase of inlet temperature. MMD for inhalation toxicology testing in EPA guidance is less than 4㎛. In this study, source temperature 20˚C and 50˚C with inlet temperature from 20˚C to 250˚C were conformed to the EPA guidance, but inlet temperature 20˚C and 50˚C for source temperature 70˚C were conformed EPA guidance. MMD for inhalation toxicology testing in OECD and EU is less than 3,um. In this study, source temperature 20˚C and 50˚C with inlet temperature from 20˚C to 250˚C were conformed to the EPA guidance, but none for source temperature 70˚C.

Spray Characteristics of Electrostatic Pressure-Swirl Nozzle

( Gabriel Nii Laryea ),( Tae Gyoung Kang ),( Soo Young No ) 한국액체미립화학회 2001 한국액체미립화학회 학술강연회 논문집 Vol.2001 No.-

제주도 해안가에서 측정된 에어로졸의 성분별 입경분포 특성

이기호,양희준,허철구 한국환경과학회 2003 한국환경과학회지 Vol.12 No.10

During the period from April to September 2002, the size distributions of ambient aerosol were measured at the coastal site at Hamduk in Jeju Island. Na^(+), K^(+), Mg^(2+), Ca^(2+) and CF exhibited mostly a bimodal coarse mode size distribution, while ammonium and sulfate were mainly in the fine size range, with maximum at around 0.54um. The average molar concentration ratio of ammonium to sulfate for fine particles was equal to 2.0±0.9. Nitrate was evenly found in both the coarse and fine modes. Elements like Al, Fe, Cu, Mg. Na. Ti. Sr and Mn were dominant in coarse particles, with the maximum at around 5.25㎛. S and Pb were mainly in the submicrometer size range. Other elements with a fine and coarse modes were V. Ni, Cu, Ba and Mo. The patterns of the size distributions of trace elements measured at the downtown in Jeju City were very similar to those at the coastal site in Hamduk. However, the amplitude of size fractional concentrations at Jeju City was narrower than that at Hamduk. While the mass median diameters for the chemical species originated from the natural origin such as marine and crust were relatively large, those for ammonium, sulfate, S and Pb were very small.