• Title/Summary/Keyword: EDC Model

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Large Eddy Simulation of Backdraft Using the Eddy Dissipation Concept Combustion Model (Eddy Dissipation Concept 연소모델을 적용한 백드래프트 대와동모사 연구)

  • Ha, Suim;Oh, Chang Bo
    • Fire Science and Engineering
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    • v.33 no.5
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    • pp.48-54
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    • 2019
  • A Large Eddy Simulation (LES), adopting the Eddy Dissipation Concept (EDC) 1-step model, was successfully performed for backdraft phenomena. The activation energy of the finite chemistry reaction in the EDC 1-step model was adjusted to simulate the backdraft. The prediction of the EDC 1-step model was similar to that of the Mixing-Controlled Fast Chemistry (MCFC) model, except when the backdraft occurred. The EDC 1-step model could be used to simulate the experimental peak pressure, but not the first peak pressure of the backdraft.

Evaluation of the Prediction Performance of FDS Combustion Models for the CO Concentration of Gas Fires in a Compartment (구획실 내 가스연료 화재의 CO 농도에 대한 FDS 연소모델의 예측성능 평가)

  • Baek, Bitna;Oh, Chang Bo;Hwang, Chel-Hong;Yun, Hong-Seok
    • Fire Science and Engineering
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    • v.32 no.1
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    • pp.7-15
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    • 2018
  • The prediction performance of combustion models in the Fire Dynamics Simulator (FDS) were evaluated by comparing with experiment for compartment propane gas fires. The mixture fraction model in the FDS v5.5.3 and Eddy Dissipation Concept (EDC) model in the FDS v6.6.3 were adopted in the simulations. Four chemical reaction mechanisms, such as 1-step Mixing Controlled, 2-step Mixing Controlled, 3-step Mixing Controlled and 3-step Mixed (Mixing Controlled + finite chemical reactions) reactions, were implemented in the EDC model. The simulation results with each combustion model showed similar level for the temperature inside the compartment. The prediction performance of FDS with each combustion model showed significant differences for the CO concentration while no distinguished differences were identified for the $O_2$ and $CO_2$ concentrations. The EDC 3-step Mixing Controlled largely over-predicted the CO concentration obtained by experiment and the mixture fraction model under-predicted the experiment slightly. The EDC 3-step Mixed showed the best prediction performance for the CO concentration and the EDC 2-step Mixing Controlled also predicted the CO concentration reasonably. The EDC 1-step Mixing Controlled significantly under-predict the experimental CO concentration when the previously suggested CO yield was adopted. The FDS simulation with the EDC 1-step Mixing Controlled showed difficulties in predicting the $CO_2$ concentration when the CO yield was modified to predict the CO concentration reasonably.

A Study of the Suitability of Combustion Chemistry in the EDC Model for the LES of Backdraft (백드래프트 현상의 LES를 위한 EDC 모델의 연소 화학반응기구 적합성 연구)

  • Myilsamy, Dinesh;Oh, Chang Bo;Han, Yong Shik;Do, Kyu Hyung
    • Fire Science and Engineering
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    • v.31 no.4
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    • pp.35-42
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    • 2017
  • Large Eddy Simulation (LES) was peformed for the backdraft occurred in a compartment filled with high-temperature methane fuel using the Fire Dynamics Simulator (FDS) of version 6. The prediction performance of FDS, adopted the Eddy Dissipation Concept (EDC) combustion model with five different chemical reaction mechanisms, was evaluated. The temporal distributions of temperature, fuel mass fraction, velocity and pressure were discussed with numerical results and the pressure variation in time was compared with that of previous experiment. The FDS adopted the EDC model showed the possibility of LES for the backdraft phenomena. However, the prediction performance of the LES with EDC model strongly depended on the chemical reaction mechanism considered. It is necessary that the suitability of the chemical reaction mechanism should be validated in advance for LES with the FDS v6 to be applied to the simulation of backdraft.

Cytotoxicity of Hyaluronic Acid Membrane Cross-linked with Lactide (락타이드로 가교시킨 히아루론산 막의 세포독성)

  • Kim, Won-Jung;Kwon, Ji-Young;Cheong, Seong-Ihl;Kim, In-Seop
    • KSBB Journal
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    • v.21 no.4
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    • pp.255-259
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    • 2006
  • The biodegradable hyaluronic acid(HA) membranes cross-linked with lactide using the crosslinking agent, 1-ethyl-3(3-dimethyl aminopropyl) carbodiimide(EDC) were prepared as a potential biocompatible material for tissue engineering. HA membranes having different mechanical properties were synthesised by varying degree of the mole ratio of lactide to HA, EDC concentration, and crosslinking temperature. HA membranes were degradable in water solution and the degradation became slower with the increasing mole ratio of lactide to HA. HA membranes were sterilized using ethylene oxide gas and extracted with cell culture medium for 24 h at $37^{\circ}C$ and 200 rpm. Cytotoxicity of the extract was tested using NIH/3T3 mouse embryo fibroblast as a model cell. Growth inhibition was not observed in the extracts of HA membranes with the mole ratios of lactide to HA, 5 or 10, and 10% EDC concentration, however 11% of growth inhibition was observed in the extract with the mole ratio of 13. Growth inhibition was not observed in the extracts of HA membranes prepared with 5% EDC or 10% EDC and the mole ratio of lactide to HA, 10, however 12% of growth inhibition was observed in the extract with 20% EDC. Cytotoxicity was not observed in the extracts of HA membranes prepared at varying crosslinking temperatures, $15^{\circ}C,\;25^{\circ}C,\;and\;28^{\circ}C$ with the mole ratio of lactide to HA, 10 and 10% EDC.

Approximation of Multiple Trait Effective Daughter Contribution by Dairy Proven Bulls for MACE (젖소 국제유전능력 평가를 위한 종모우별 다형질 Effective Daughter Contribution 추정)

  • Cho, Kwang-Hyun;Choi, Tae-Jeong;Cho, Chung-Il;Park, Kyung-Do;Do, Kyoung-Tag;Oh, Jae-Don;Lee, Hak-Kyo;Kong, Hong-Sik;Lee, Joon-Ho
    • Journal of Animal Science and Technology
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    • v.55 no.5
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    • pp.399-403
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    • 2013
  • This study was conducted to investigate the basic concept of multiple trait effective daughter contribution (MTEDC) for dairy cattle sires and calculate effective daughter contribution (EDC) by applying a five lactation multiple trait model using milk yield test records of daughters for the Multiple-trait Across Country Evaluation (MACE). Milk yield data and pedigree information of 301,551 cows that were the progeny of 2,046 Korean and imported dairy bulls were collected from the National Agricultural Cooperative Federation and used in this study. For MTEDC approximation, the reliability of the breeding value was separated based on parents average, own yield deviation and mate adjusted progeny contribution. EDC was then calculated by lactation using these reliabilities. The average number of recorded daughters per sire by lactations were 140.57, 94.24, 55.14, 29.20 and 14.06 from the first to fifth lactation, respectively. However, the average EDC per sire by lactation using the five lactation multiple trait model was 113.49, 89.28, 73.56, 54.02 and 35.08 from the first to fifth lactation, respectively, while the decrease of EDC in late lactations was comparably lower than the average number of recorded daughters per sire. These findings indicate that the availability of daughters without late lactation records is increased by genetic correlation using the multiple trait model. Owing to the relatedness between the EDC and reliability of the estimated breeding value for sire, understanding the MTEDC algorithm and continuous monitoring of EDC is required for correct MACE application of the five lactation multiple trait model.

Measures to improve water quality for West Nakdong basin using EFDC model (EFDC 모형을 활용한 서낙동강 유역의 수질개선 방안)

  • Kang, Bo Seung;Kong, Hyuk Jun;Park, In Hyeok;Shin, Ik Hwan
    • Proceedings of the Korea Water Resources Association Conference
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    • 2017.05a
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    • pp.95-99
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    • 2017
  • 서낙동강 하류에 국내 최초로 친수구역 활용에 관한 특별법에 따른 부산 에코델타시티(Eco Delta City, EDC) 조성사업이 시행 중에 있으며, 친수공간 확보 및 친수활동에 대한 관심의 증가로 서낙동강 수질개선에 대한 필요성이 증가하고 있다. 이에 부산 EDC 사업에서는 친수활동을 위한 목표 수질(II급수)을 설정하고 목표수질을 달성하기 위해 EFDC 모형을 활용하여 서낙동강 유역의 수질개선 방안을 검토하였다. 서낙동강 유역의 하수처리 정비 등을 통한 오염부하의 삭감, 부산 EDC 사업의 오염부하 삭감 및 서낙동강, 평강천, 맥도강 물순환 등의 대책을 통하여 목표 수질을 달성할 수 있을 것으로 연구되었다.

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Probability Map of Migratory Bird Habitat for Rational Management of Conservation Areas - Focusing on Busan Eco Delta City (EDC) - (보존지역의 합리적 관리를 위한 철새 서식 확률지도 구축 - 부산 Eco Delta City (EDC)를 중심으로 -)

  • Kim, Geun Han;Kong, Seok Jun;Kim, Hee Nyun;Koo, Kyung Ah
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.26 no.6
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    • pp.67-84
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    • 2023
  • In some areas of the Republic of Korea, the designation and management of conservation areas do not adequately reflect regional characteristics and often impose behavioral regulations without considering the local context. One prominent example is the Busan EDC area. As a result, conflicts may arise, including large-scale civil complaints, regarding the conservation and utilization of these areas. Therefore, for the efficient designation and management of protected areas, it is necessary to consider various ecosystem factors, changes in land use, and regional characteristics. In this study, we specifically focused on the Busan EDC area and applied machine learning techniques to analyze the habitat of regional species. Additionally, we employed Explainable Artificial Intelligence techniques to interpret the results of our analysis. To analyze the regional characteristics of the waterfront area in the Busan EDC district and the habitat of migratory birds, we used bird observations as dependent variables, distinguishing between presence and absence. The independent variables were constructed using land cover, elevation, slope, bridges, and river depth data. We utilized the XGBoost (eXtreme Gradient Boosting) model, known for its excellent performance in various fields, to predict the habitat probabilities of 11 bird species. Furthermore, we employed the SHapley Additive exPlanations technique, one of the representative methodologies of XAI, to analyze the relative importance and impact of the variables used in the model. The analysis results showed that in the EDC business district, as one moves closer to the river from the waterfront, the likelihood of bird habitat increases based on the overlapping habitat probabilities of the analyzed bird species. By synthesizing the major variables influencing the habitat of each species, key variables such as rivers, rice fields, fields, pastures, inland wetlands, tidal flats, orchards, cultivated lands, cliffs & rocks, elevation, lakes, and deciduous forests were identified as areas that can serve as habitats, shelters, resting places, and feeding grounds for birds. On the other hand, artificial structures such as bridges, railways, and other public facilities were found to have a negative impact on bird habitat. The development of a management plan for conservation areas based on the objective analysis presented in this study is expected to be extensively utilized in the future. It will provide diverse evidential materials for establishing effective conservation area management strategies.

Immobilization of Proteins on Magnetic Nanoparticles

  • Wang, Tzu-Hsien;Lee, Wen-Chien
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.8 no.4
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    • pp.263-267
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    • 2003
  • Magnetic nanoparticles prepared from an alkaline solution of divalent and trivalent iron ions could covalently bind protein via the activation of Nethyl-N-(3-dimethylaminopropyl) carbodiimide (EDC). Trypsin and avidin were taken as the model proteins for the formation of protein-nanoparticle conjugates. The immobilized yield of protein increased with molar ratio of EDC/nanoparticie. Higher concentrations of added protein could yield higher immobilized protein densities on the particles. In contrast to EDC, the yields of protein immobilization via the a ctivation of cyanamide were relatively lower. Nanoparticles bound with avidin could attach a single-stranded DNA through the avidin-biotin interaction and hybridize with a DNA probe. The DNA hybridization was confirmed by fluorescence microscopy observations. Immobilized DNA on nanoparticles by this technique may have widespread applicability to the detection of specific nucleic acid sequence and targeting of DNA to particular cells.

Formation of MILD Combustion using Co-flow MILD Combustor (동축류 마일드 연소기를 적용한 마일드 연소 형성 연구)

  • Lee, Pil Hyong;Hwang, Sang Soon
    • Journal of the Korean Society of Combustion
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    • v.22 no.3
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    • pp.8-16
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    • 2017
  • MILD combustion was first developed to suppress thermal NOx formation in combustor for heating industrial furnaces. In this paper, the effect of co-flow MILD combustor geometry and operating conditions on the formation of MILD combustion was analyzed using 3 dimensional numerical simulation. The numerical simulations were carried out using ANSYS Fluent. The combustion and turbulence flow was modeled using the Eddy Dissipation Concept(EDC) model and realizable $k-{\varepsilon}$ model respectively. The results show that the high temperature region and average temperature decreased due to an increase in the air velocity and decrease the wall thickness of fuel nozzle. In particular, the MILD combustion flame was found to be stable with a combustion flame region at fuel velocity 10 m/s, air velocity 20 m/s, fuel nozzle thickness 1.0 mm, equivalence ratio 0.9, and outlet area ratio 40%.

Effect of Nonylphenol on the Structure of Adrenal Cortex in F1 Generation Rats

  • Hee-Su Kim;Sung-Ho Lee
    • Development and Reproduction
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    • v.26 no.4
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    • pp.175-182
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    • 2022
  • Previous studies, including our own, indicate that distinct morphological changes in rodent adrenal cortex could be induced by exposure of endocrine disrupting chemicals (EDC). In the present study, we conducted histological analyses of adrenocortical substructure using a nonylphenol-treated F1 rat model. The adrenal weight of NP-5000 group was significantly declined in female rats (p<0.001), while the adrenal weights of NP-treated groups were not significantly changed in male rats. The thickness of zona glomerulosa layers of female rats in NP-5000 group was significantly declined (p<0.001) but zona fasciculata layers were not changed. The zona reticularis layers of NP-treated group were significantly thinner than those of control group (NP-50, p<0.05; NP-5000, p<0.01). In male adrenal glands, there was no significant change of zona glomerulosa layers in NP-treated groups while the thickness of zona fasciculata in NP-5000 group was significantly decreased (p<0.01). Like female rats, the thickness of zona reticularis in NP-treated groups was significantly decreased (NP-50, p<0.001; NP-5000, p<0.05). Present study demonstrated that the adrenal histology could be altered by low-dose NP exposure in F1 rats, and the effect might be sexually dimorphic. Further study will be helpful for understanding possible adrenal pathophysiology induced by EDC exposure, and EDC-related sexually dimorphic phenomena in rodent adrenals.