• Title/Summary/Keyword: spout

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A Study of Manhole Bursting due to Surcharged Flow in Large Sewer System (대규모 간선에 있어서 써차지 흐름에 동반되는 맨홀뚜껑 비산현상에 관한 연구)

  • Choi, Sung-Mo
    • Journal of the Korean Society of Hazard Mitigation
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    • v.4 no.2 s.13
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    • pp.53-59
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    • 2004
  • The mechanism of manhole bursting which occurs at excess rainfall events Is studied by using both the physical model and the numerical model (SWMM ; Storm Water Management Model). The result of numerical simulation to steep pressure rising agrees well with that of the physical model at the sewer system under surcharged flow. A cause of manhole bursting is an expansion and spout of the condensed all at manhole that results from the surcharged flow and press wave propagation caused by gate operation or closure of conduit at pumping station.

Effect of Microbial Control on Alfalfa Sprout Vegetable by Depending on Sanitization Method in Kindergarten Foodservice (유치원 급식으로 이용되는 알팔파 새싹채소의 소독방법에 따른 미생물제어 효과)

  • Woo, Suhee
    • Journal of The Korean Society of Integrative Medicine
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    • v.4 no.4
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    • pp.109-117
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    • 2016
  • Purpose : This study was designed to provide basic data of effective sanitization method of sprout vegetable for microbiological safety. Methods : Sanitization treatments were performed by dipping the sprout into chlorine and vinegar water. Microbial analysis were composed of the total plate count(TPC) and coliform group count(CGC). Result : Among chlorine water sanitization, the microbial reduction was largest in 100ppm chlorine water, and its TPC and coliform group count decreased to 6.01 log CFU/g and 5.06 log CFU/g. The effective dipping time in 100ppm chlorine water treatment was 5.97 log CFU/g and 5.91 log CFU/g for 30min and 60min, in which TPC were below the microbiological safety limits of 6.00 log CFU/g. Coliform group counts were decreased to 5.44, 5.46, 5.42 log CFU/g in the dipping the spouts for 30min, 60min and 90min. As a result of sanitizing alfalfa spout by vinegar water, a microbial counts tended to decrease with increasing concentration and the dipping time. The effective concentration of vinegar water was 2% for TPC(6.00 log CFU/g) and 1% for coliform group count(5.20 log CFU/g). With 1% vinegar water treatment, TPC became below the microbiological safety limits in all samples and in particular, the sample treated for 60min and 90min(4.93, 4.54 log CFU/g). While coliform group counts were decreased to 3.91 log CFU/g in the dipping the sprouts for 90min, those were still beyond the permitted limit. Conclusion : To secure the food safety of food service facilities including kindergarten feeding, it is considered that along with the systematic study of effective disinfection method for microbiological control at the preconditioning level of spout vegetable within the range of secured maleficence to human body, and the study regarding the measures to lower the initial microbiological pollution of spout vegetable.

Characterization of flow properties of pharmaceutical pellets in draft tube conical spout-fluid beds

  • Foroughi-Dahr, Mohammad;Sotudeh-Gharebagh, Rahmat;Mostoufi, Navid
    • Journal of Industrial and Engineering Chemistry
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    • v.68
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    • pp.274-281
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    • 2018
  • Experimental studies of the hydrodynamic performance of the draft tube conical spout-fluid bed (DCSF) were conducted using pharmaceutical pellets. The experiments were carried out in a DCSF consisted of two sections: (a) a conical section with the cross section of $120mm{\times}250mm$ and the height of 270 mm, (b) a cylindrical section with the diameter of 250 mm and the height of 600 mm. The flow characteristics of solids were investigated with a high speed camera and a pezoresistive absolute pressure transducer simultaneously. These characteristics revealed different flow regimes in the DCSF: packed bed at low gas velocities, fluidized bed in draft tube at higher gas velocities until minimum spouting, and spouted bed. The stable spouting was identified by the presence of two dominant frequencies of the power spectrum density of pressure fluctuation signature: (i) the frequency band 6-9 Hz and (ii) the frequency band 12-15 Hz. The pressure drops across the draft tube as well as the annulus measured in order to better recognize the flow structure in the DCSF. It was observed that the pressure drop across the draft tube, the pressure drop across the annulus, and the minimum spouting velocity increase with the increase in the height of draft tube and distance of the entrainment zone, but with the decrease in the distributor hole pitch. Finally, this study provided novel insight into the hydrodynamic of DCSF, particularly minimum spouting and stable spouting in the DCSF which contains valuable information for process design and scale-up of spouted bed equipment.

Removal Characteristics of $SO_2$ in the Coal Combustion Flue Gas Treatment Convergence System (석탄화력발전소 현장의 석탄연소 배가스 고도처리용 건식 분류층 반응 실증장치에서의 $SO_2$ 제거성능 특성)

  • Jeon, Seong-Min;Park, Hyung-Sang;Park, Young-Ok
    • Particle and aerosol research
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    • v.9 no.4
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    • pp.239-246
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    • 2013
  • The purpose of this study is to determine the feasibility of dry-type desulfurization process for actual application to coal-fired power plant. We used actual exhaust gas from Facility Y, Plant #2 to fabricate a demo-scale testing device to attempt to improve the efficiency of desulfurization. A spout-bed circulating dry scrubber convergence system connecting turbo reactor with bag filter was devised, then analyzed for performance characteristics of $SO_2$ removal for Ca/S mole ratio, superficial gas velocity, and ammonia injection, and for secondary reaction characteristics of the non-reactive sorbent at the bag filter. As a result, the installation of spout-bed circulating dry scrubber convergence system showed better economy and efficiency for removing sulfur than the existing wet/semidry-type desulfurization process. In addition, the best efficiency for desulfurization occurred when connected to the bag filter, with differential pressure maintained at 150 $mmH_2O$.