• Title/Summary/Keyword: Wet scavenging

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Experimental Studies on Wet Scavenging of Atmospheric Aerosols by Rain Drops

  • Park Jeong-Ho;Suh Jeong-Min;Choi Kum-Chan
    • Journal of Korean Society for Atmospheric Environment
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    • v.21 no.E3
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    • pp.87-94
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    • 2005
  • Wet scavenging by rain drops is a most important removal process of air pollutants. In order to study the scavenging mechanisms of aerosol particles, the characteristics of chemical components in the rain water were examined as a function of the amount of rainfall. Rain water were collected continuously and separated into the soluble and insoluble components. The elemental concentrations in both components were determined by a PIXE analysis. The physical and chemical characteristics of atmospheric aerosols during the rainfall events were measured simultaneously. The elemental concentrations in rain water decreased substantially just after rain started and then gradually declined in subsequential rain fall exceeding 1.0 mm. The large particles were scavenged more easily than the fine particles. Fe, Ti and Si in rain water were in high insoluble state. Contrarily, almost whole of S was dissolved in rain water.

A Theoretical Study on Wet Scavenging of Atmospheric Aerosols by Rain Drops (대기에어로졸 입자의 이론적 강수세정에 관한 연구)

  • 박정호;최금찬
    • Journal of Korean Society for Atmospheric Environment
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    • v.15 no.1
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    • pp.1-11
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    • 1999
  • In this work, a theoretical model has been formulated which allows the study of the scavenging efficiencies of aerosol particles by the rain drops. Aerosol particles are scavenged by the simultaneous brownian diffusion, interception and inertial impaction force. In addition the calculations based on the collision efficiency model are carried out for the collision of aerosol particles with diameter range 0.01~30 $mu extrm{m}$ and rain drops with diameter 0.02$\times$$2^{n/3}$(n=1, 2, …, 17)cm. The results indicate that: (1) the below-cloud scavenging affects mainly the coarse particles (>3 ${\mu}{\textrm}{m}$), the fine particles remaining almost unchanged; (2) the scavenging efficiencies by below-cloud in the heavy rain (rain intensity, 10 mm/hr) surpass the efficiency found in the drizzle rain (rain intensity, 1 mm/hr).

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Effects of Peanut Sprout Extract and Powder on Quality Characteristics and Antioxidant Activity of Wet Noodles (새싹땅콩 분말 및 추출물이 생면 품질특성과 항산화 활성에 미치는 영향)

  • Kim, Min-Ji;Lee, Soo-Jeong
    • The Korean Journal of Food And Nutrition
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    • v.28 no.3
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    • pp.507-516
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    • 2015
  • This study investigated the quality characteristics and antioxidant activities of wet noodles as well as their cooking properties following the addition of peanut sprout extract (PSE) and powder (PSP), which are known to contain a significant level of resveratrol. Wet noodles were prepared with 0, 2.5, 5, 7.5 and 10% PSE and PSP. Quality characteristics such as increasing volume of noodle, water ratio, turbidity of cooking water and color, texture, and sensory evaluation were then assessed. Additionally, the total resveratrol content in the cooked noodles was analyzed by HPLC and DPPH free radical scavenging capacity. As the amount of PSE and PSP increased, the L value of wet and cooked noodles significantly decreased, whereas the a and b values increased (p<0.001). The L value of cooked noodles was significantly lower compared to wet noodles (p<0.001) whereas the a and b values were higher. For the cutting intensity properties of the cooked noodles, hardness was reduced with increasing amounts of PSE (p<0.001), and was significantly increased in proportion to the amount of PSP (p<0.05). Meanwhile, springiness was not significantly different in all groups. Total resveratrol content and free radical scavenging activity significantly increased in proportion to the amounts of PSE and PSP (p<0.001), especially in noodles containing 5%, 7.5% and 10% PSE and PSP. Finally, sensory evaluation of PSE noodle revealed that color, flavour, taste were significantly decreased (p<0.05). But there was no difference in overall acceptance among cooked noodles with 2.5% to 5% PSE comparison to the control. Sensory characteristics in the PSP noodle showed similar results. In conclusion, these findings suggest that peanut sprout extract and powder could be potentially used as functional food ingredients. In addition, up to 5% PSE and PSP can be substituted for wheat flour.

Estimation of 222Rn Concentration in the Lower Troposphere during Precipitation Using Wet Scavenging Model for its Decay Products

  • Takeyasu, Masanori;Takeishi, Minoru
    • Asian Journal of Atmospheric Environment
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    • v.4 no.1
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    • pp.20-25
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    • 2010
  • The gaseous $^{222}Rn$ concentration at the level of clouds was estimated by using the wet scavenging model of its decay products with the observed data of environmental radiation at the ground. And the origin of the $^{222}Rn$ was also discussed. The estimation was done for a precipitation event on Dec. 26-27, 2003, when a large increase of the radiation was observed in Tokai-mura in Ibaraki, Japan. From a backward trajectory analysis, the origin of $^{222}Rn$ atoms for that event was traced back to the northeastern part of China, and it was expected that the large amount of $^{222}Rn$ emitted in the northeastern part of China was transported to Tokai-mura by the Eurasian continental air mass.

Scavenging Properties of Atmospheric Carbon by Precipitation

  • Hwang, Kyung-Chul;Ma, Chang-Jin;Cho, Ki-Chul
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.E2
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    • pp.77-85
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    • 2004
  • In order to investigate the scavenging property of airborne carbonaceous particles by precipitations, rainwater, snow sample, and total suspended particulate matter (TSP) were collected at a heavily industrialized urban site. Elemental carbon (EC) contents of both rainwater and snow water were deter-mined using elemental analysis system. EC concentrations in rain samples varied from 33.6 to 166.6 $\mu\textrm{g}$ L$^{-1}$ with an average 47.2 $\mu\textrm{g}$ L$^{-1}$ . On the other hand, those of snow samples in three times snow events were ranged from 122.4 to 293.3 $\mu\textrm{g}$ L$^{-1}$ . As might be expected, EC showed the significantly high scavenging rate at the initial rainfall. The average total carbon (TC) scavenging rate by washout mechanisms was 57.6% for five rainfall events. The scavenging rate of EC gradually increased in proportion to the increasing rainfall intensity and rainfall amount.

Quality Characteristics of Wet Noodles with Allium hookeri Powder (삼채(Allium hookeri) 분말을 첨가한 생면의 품질 특성)

  • Cheon, Se-Young;Kim, Kyoung-Hee;Yook, Hong-Sun
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.45 no.1
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    • pp.84-90
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    • 2016
  • This study investigated the quality of wet noodles added with Allium hookeri powder. Wet noodles were prepared by addition of 0, 2, 6, and 10% powder to flour of the basic formulation. The water binding capacity of Allium hookeri powder was higher than that of flour. Swelling power and solubility increased with increased temperature. The weight, water absorption, volume, and turbidity values of cooked noodles showed no significant differences. The lightness value decreased with an increase in Allium hookeri powder content. The redness and yellowness values increased with an increase in Allium hookeri powder content. The textural properties of cooked noodles decreased with an increase in Allium hookeri powder content. Antioxidative activity as measured by 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of wet noodles increased as the concentration of Allium hookeri powder increased. The highest quality noodles were obtained with 2% Allium hookeri powder in the wet noodle formula.

Numerical Simulations of Dry and Wet Deposition over Simplified Terrains

  • Michioka, T.;Takimoto, H.;Ono, H.;Sato, A.
    • Asian Journal of Atmospheric Environment
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    • v.11 no.4
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    • pp.270-282
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    • 2017
  • To evaluate the deposition amount on a ground surface, mesoscale numerical models coupled with atmospheric chemistry are widely used for larger horizontal domains ranging from a few to several hundreds of kilometers; however, these models are rarely applied to high-resolution simulations. In this study, the performance of a dry and wet deposition model is investigated to estimate the amount of deposition via computational fluid dynamics (CFD) models with high grid resolution. Reynolds-averaged Navier-Stokes (RANS) simulations are implemented for a cone and a two-dimensional ridge to estimate the dry deposition rate, and a constant deposition velocity is used to obtain the dry deposition flux. The results show that the dry deposition rate of RANS generally corresponds to that observed in wind-tunnel experiments. For the wet deposition model, the transport equation of a new scalar concentration scavenged by rain droplets is developed and used instead of the scalar concentration scavenged by raindrops falling to the ground surface just below the scavenging point, which is normally used in mesoscale numerical models. A sensitivity analysis of the proposed wet deposition procedure is implemented. The result indicates the applicability of RANS for high-resolution grids considering the effect of terrains on the wet deposition.

Modeling Study on Dispersion and Scavenging of Traffic Pollutants at the Location Near a Busy Road

  • Ma, Chang-Jin
    • Asian Journal of Atmospheric Environment
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    • v.9 no.4
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    • pp.272-279
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    • 2015
  • The information about the dispersion and scavenging of traffic-related pollutants at the locations near busy expressways is very helpful to highway planners for developing better plans to reduce exposures to air pollution for people living as well as children attending schools and child care centers near roadways. The objective of the current study was to give information in the dispersion and scavenging of vehicle-derived pollutants at the region near a busy urban expressway by a combination of two different model calculations. The modified Gaussian dispersion model and the Lagrange type below-cloud scavenging model were applied to evaluate $NO_x$ dispersion and DEP (Diesel exhaust particles) wet removal, respectively. The highest $NO_x$ was marked 53.17 ppb within 20-30 meters from the target urban expressway during the heaviest traffic hours (08:00AM-09:00AM) and it was 2.8 times higher than that of really measured at a nearby ambient measuring station. The calculated DEP concentration in size-resolved raindrops showed a continuous decreasing with increasing raindrop size. Especially, a noticeable decrease was found between 0.2 mm and 1.0 mm raindrop diameter.

Quality Characteristics of Wet Noodles Containing Different Amounts of Doraji Powder (도라지 분말 첨가량에 따른 생면의 품질 특성)

  • Yu, Hyeon-Hee;Zhu, RuiYu;Kim, Seon Hyo;Oh, Jong Chul
    • The Korean Journal of Food And Nutrition
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    • v.33 no.1
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    • pp.37-48
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    • 2020
  • In this study, the quality characteristics and antioxidant activities of wet noodles added with doraji (Platycodon grandiflourm) powder at concentrations of 1%, 2%, 3%, and 4%, respectively, were investigated. The crude protein, crude fat, crude ash, crude fiber, and moisture contents of the dried doraji powder were 11.00%, 0.95%, 4.10%, 29.64%, and 6.21%, respectively. As the added amount of doraji powder increased, weight, volume, and water absorption of the wet noodles after cooking decreased. However, the turbidity of the soup increased. Color L values of wet and cooked noodles decreased, while a and b values increased by the addition of doraji powder. Texture measurement indicated that hardness, cohesiveness, springiness, and chewiness of the cooked noodles decreased by addition of doraji powder. The total polyphenol contents and DPPH radical scavenging activity in wet noodles added with doraji powder increased with increasing amounts of doraji powder. Finally, sensory evaluation of wet noodles added with doraji powder revealed that taste significantly decreased. However, flavor, color, texture, appearance, and overall acceptance scores for the 1% addition group ranked significantly higher than those of the other groups. In conclusion, these findings suggest that doraji powder could be used as functional food ingredients.

Quality and Antioxidant Activity of Wet Noodles Supplemented with Brown Rice and Sorghum Powders (현미 및 수수 첨가에 따른 생면의 품질특성과 항산화 효과)

  • Cheng, Li;Kim, Sin-Joung;Kil, Jeung-Ha;Park, Kun-Young
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.43 no.4
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    • pp.530-536
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    • 2014
  • In this study, we investigated the quality and antioxidant activity of wet noodles fortified by adding brown rice and sorghum powders. Wet noodles were divided into four groups: WN-p (wheat flour 100%, purified salt 2%), WBN-b (wheat flour 80%, brown rice powder 20%, bamboo salt (${\times}1$) 2%), WBSN-b (wheat flour 80%, brown rice powder 10%, sorghum powder 10%, bamboo salt (${\times}1$) 2%), and WSN-b (wheat flour 80%, sorghum powder 20%, bamboo salt (${\times}1$) 2%). The wet noodles were evaluated for their quality characteristics and capacities to scavenge free radicals. The weight, volume, capacity to absorb water, and turbidity of cooked WBSN-b were close to those of cooked WN-p. Springiness, cohesiveness, and chewiness of cooked WBSN-b were the highest among all cooked noodles added with brown rice or sorghum powders and textural properties of cooked WBSN-b were not significantly different from WN-P. In the sensory evaluation, the overall acceptance of WBSN-b received the highest score of 6.4 points, which was higher than the score for WN-p. DPPH and hydroxyl radical scavenging activities increased significantly with addition of brown rice and sorghum powder, and radical scavenging activities of WBSN-b and WSN-b were the highest. In conclusion, wet noodles added with 10% brown rice powder, 10% sorghum powder, and 2% bamboo salt (${\times}1$) exhibited the same quality properties of WN-p. Addition of 10% brown rice powder, 10% sorghum powder, and 2% bamboo salt (${\times}1$) increased the sensory and antioxidant activities of wheat flour noodles.