• Title/Summary/Keyword: Dry-out

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Analysis of the Sedimentation Status Test for Type-3 Dry Chemical Powder with Changes in Internal Pressure of the Dry Chemical Extinguisher (분말소화기의 내부압력 변화에 따른 제3종 분말소화약제의 침강도 시험)

  • Ju-Dal Son;Seo-Young Kim;Ha-Sung Kong
    • Journal of the Korea Safety Management & Science
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    • v.25 no.1
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    • pp.67-74
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    • 2023
  • This study aims to measure sedimentation status change with the changes in internal pressure for dry chemical extinguishers of various use periods and analyze the suitability of the fire extinguishers' performance criteria. When the internal pressure of the fire extinguisher is 0%, 2 out of 10 new dry chemical powders for the 5 elapsed years were noted to be suitable, including 3 recycled dry chemical powders with 5 elapsed years that were found eligible. One out of 10 new dry chemical powders for 10 elapsed years was shown as suitable. Also, one new dry chemical powder for 13 elapsed years was suitable. When the internal pressure of the fire extinguisher was 50%, all 10 out of 10 new dry chemical powders for 5 years, recycled one with 5 elapsed years, and a new one with 10 elapsed years were found to be suitable, while 9 new dry chemical powders for 13 years were shown as suitable. When the internal pressure of the fire extinguisher was normal, new ones with 5 elapsed years, recycled ones with 5 elapsed years, new ones with 10 elapsed years, and new ones with 13 elapsed years were all 10 out of 10 samples noted as suitable. In summarizing the experiment results, it was found that the sedimentation status, one of the fire extinguisher's physical properties experiments, affects the fire extinguisher's performance criteria rather than the change with use periods.

Dry-out conditions of free-breathing PEMFC with dry $H_2$ gas (자연급기 무가습 연료전지의 Dry-out조건)

  • Park, Sang-Kyun
    • Journal of Advanced Marine Engineering and Technology
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    • v.30 no.2
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    • pp.225-230
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    • 2006
  • This study investigates drying condition when a small fan is added to a operating the free-breathing proton exchange membrane fuel cells (PEMFCs) with dry $H_2$ and Air. Polarization tests were conducted on PEMFCs at cell temperatures between 30 and $50^{\circ}C$ under dry operation. In the results, the cell performance strongly depended on the cell temperature and the cathode gas stoichiometric flow rates. The cell performance increases as cell temperature decreases from 50 to $30^{\circ}C$. In the domain where the stoichiometry of air is quite large, reduction of the concentration overpotential compensated the increased internal resistance due to drying. The maximum performance was obtained at the small air flow rate beyond which flooding occurs. This indicates that the fan should be operated in the stoichiometry domain with a well designed cell structure to avoid flooding.

Spent fuel simulation during dry storage via enhancement of FRAPCON-4.0: Comparison between PWR and SMR and discharge burnup effect

  • Dahyeon Woo;Youho Lee
    • Nuclear Engineering and Technology
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    • v.54 no.12
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    • pp.4499-4513
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    • 2022
  • Spent fuel behavior of dry storage was simulated in a continuous state from steady-state operation by modifying FRAPCON-4.0 to incorporate spent fuel-specific fuel behavior models. Spent fuel behavior of a typical PWR was compared with that of NuScale Power Module (NPMTM). Current PWR discharge burnup (60 MWd/kgU) gives a sufficient margin to the hoop stress limit of 90 MPa. Most hydrogen precipitation occurs in the first 50 years of dry storage, thereby no extra phenomenological safety factor is identified for extended dry storage up to 100 years. Regulation for spent fuel management can be significantly alleviated for LWR-based SMRs. Hydride embrittlement safety criterion is irrelevant to NuScale spent fuels; they have sufficiently lower plenum pressure and hydrogen contents compared to those of PWRs. Cladding creep out during dry storage reduces the subchannel area with burnup. The most deformed cladding outer diameter after 100 years of dry storage is found to be 9.64 mm for discharge burnup of 70 MWd/kgU. It may deteriorate heat transfer of dry storage by increasing flow resistance and decreasing the view factor of radiative heat transfer. Self-regulated by decreasing rod internal pressure with opening gap, cladding creep out closely reaches the saturated point after ~50 years of dry storage.

Feasibility Study of Dry Forming with Dry Forming Mould (원주형 건식초지기를 이용한 건식초지 가능성 평가)

  • Kim, Jong-Min;Lee, Hak-Lae
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.41 no.1
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    • pp.9-16
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    • 2009
  • Cylindrical dry forming mould was developed to carry out a feasibility study of dry forming of papers. The effect of disintegration, forming, humidification and pressing on dry formed papers was examined. Dry disintegrated fibers showed the similar fiber length distribution to wet disintegrated fibers, but they showed distorsion and damaged appearance on the surface. Process parameters required to form a uniform fiber pad was investigated. A proper screening and air dispersion method was selected that gives proper formation. Humidification and pressing conditions were examined to get a good dry formed papers in dry forming. Results showed that dry forming method can be used to make a sheets with reasonable formation and properties.

Effect of Dry Deposition on Water Quality -The comparison of several methodologies for estimating dry deposition flux (수질에 대한 대기건식침적의 영향 - 건식침적량 추정 방법론의 비교를 중심으로)

  • Cheong, Jang-Pyo
    • Journal of Korean Society of Water and Wastewater
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    • v.22 no.1
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    • pp.159-168
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    • 2008
  • A special field experiment has been carried out from March 2001 to June 2001 at the Changhowon in Kyunggi to investigate a better methodology for the estimation of dry deposition of pollutions applicable in Korea. In this study, dry deposition plate was used to measure of total and water soluble acidic mass fluxes, and CPRI(Coarse Particle Rotary Impactor), CI(Cascade Impactor) were also used to measure ambient concentrations in various particle size ranges. Sehmel-Hodgson model was used to estimate dry depostion velocity and Weibull probability distribution function was applied to get generalized particle size distribution for the size fractioned concentration data sampled by CPRI and CI. Atmospheric dry deposition fluxes of mass and ionic matters estimated by the various techniques(one-step, multi-step, equi-concentration, subdivision for only the coarse particle range, applying Weibull distribution function, etc.) were compared to flux data sampled by DDP. It was found out that the deposition fluxes estimation methodology calculated by the each particle size range devided by particle size distribution characteristics and the rapidly changed points of deposition velocity using Weibull probability distribution function was the most applicable.

On the drying out of bipolar membranes

  • Kedem, Ora;Ghermandi, Andrea;Messalem, Rami
    • Membrane and Water Treatment
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    • v.4 no.3
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    • pp.215-222
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    • 2013
  • The maximum current density that can be achieved in bipolar membrane electrodialysis is limited by the sharp increase in resistance that is experienced when the water content at the membrane interface is not adequately replenished and the membranes dry out. In this paper we show how the water content near the interface depends on the properties of the membranes. A water retaining parameter is introduced, which characterizes the thermodynamic properties of the membrane material and may be used to guide the choice of polymers for mitigation of the dry-out problem.

A Study on the Burn-out Printing of Cellulose-blend Velvet (셀룰로오스계 파일직물의 탄화가공)

  • 김호정
    • Journal of the Korean Society of Clothing and Textiles
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    • v.23 no.5
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    • pp.757-763
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    • 1999
  • The burn-out technique is used to result in the velvet cloth being patterned in open and solid areas by carbonize the cellulose fiber. It is examined how to burn out the cellulose part of the velvet without damage of the other part. The print paste indalca solution is mixed with sodium hydrogensulfate and lycerine and then screen-printed on the back side of the velvet. The effects of process conditions such as concentration of sodium hydrogensulfate dry heat fixation temperature and time pull no. and glycerine contents on the properties of ground farics were investigated. The yellowness index and the breaking load of silk ground fabrics afected by the process conditions especially concentration of sodium hydrogensulfate dry heat fixation temperature.

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A Study on the Compactibility of Quick-lime Mixed with Soil (생석탄 혼합토의 다짐성에 관한 연구)

  • 김철규
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.12 no.1
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    • pp.1883-1886
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    • 1970
  • This study was made to obtain the optium compaction of quicklime mixed with soil and to find out the relation of the quicklime mix ratio, dry density and strength by changing the compaction rounds. The obtained results are as follows. 1. The maximun dry density of unmixed soil in not distinguishable, while that of mixed soil is distinguishable. 2. What the increase of quicklime mix ratio, the dry density and strength increase and the optimum quicklime mix ratio could be obtained. 3. With the increase of compaction rounds, the dry density and strength increase, while they decrease in a certain limit and maximum dry density and strength could be obtained.

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A Study on the Dry CVT with Movable Flange of Ball Type (볼 형태의 가동플랜지를 갖는 건식 무단변속기에 대한 연구)

  • Kwon, Young-Woong;Choi, Sang-Soo
    • Journal of Power System Engineering
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    • v.17 no.1
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    • pp.85-90
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    • 2013
  • Dry CVT consists of a driving pulley and a driven pulley joined by rubber V-belt. Each pulley consists of a fixed flange and a movable flange. The movable flange moves toward a fixed flange under the actuation of a centrifugal roller, as the driving pulley speed increases. The important claim which have an influence on the performance of the Dry CVT is the wear of the centrifugal roller. In this study ball type is proposed instead of roller type of movable flange to resolve the claim. Simulation is carried out for new model to verificate performance, experiments are carried out for new model to evaluate performances.

Broadcasting effect of Chitosan solution on dry matter prodution in Ladino clover(Trifolium repens) (Ladino clover(Trifolium repens)의 건물생산에 미치는 Chitosan 용액의 전면시용효과)

  • 이주삼
    • Korean Journal of Organic Agriculture
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    • v.4 no.2
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    • pp.79-85
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    • 1995
  • This experiment was carried out to broadcating effect of chitosan solution levels on dry matter production in Ladino clover(Trifolium repens). Chitosan solution was applie at 6 levels, 0%, 0.01%, 0.05%, 0.1%, 0.5% and 1.0%, respectively. The results obtained were summarized as follows ; 1. The dry matter yields of chitosan treatment plot were about 30%~63% more than the dry matter yield of control plot in all cuts. 2. Total dry matter yield was produced by 659.7kg/10a at levels of 0.05%, it was significantly higher than other chitosan solution levels. 3. The predictable highest yield and economic yield of Ladino clover could be obtained at 0.05% and 0.01% solution levels, respectively. 4. The relative dry matter yields for total dry matter yield were 66.7%, 18.3% and 15.0% at 1st, 2nd and 3rd cut, respectively. Chitosan application at early spring was affected to increasing the dry matter yield of 1st cut.

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