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열처리 채소의 MAP에 적합한 포장재 구명

  • 강준수;조학래
    • Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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    • 2003.04a
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    • pp.142.2-142
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    • 2003
  • 본 연구에서는 풋고추, 대파와 깻잎에 물리적인 장해를 주지 않고 저장성을 향상시킬 수 있는 열처리 조건을 설정하고, 열처리한 채소의 MAP에 적합한 포장재를 검색하기 위한 실험을 수행하였다. 대파를 55$^{\circ}C$ 온수에서 1분 침지하고, 풋고추와 깻잎은 5$0^{\circ}C$ 온수에서 10초와 5초 각각 침지하면 저장 중 관능적 품질이 비열처리한 대조구보다 우수하게 나타났다. 열처리한 채소의 호흡속도는 비열처리 채소에 비하여 30~45%정도 상승하였다. 열처리 채소의 MAP에 적합한 포장재를 검색하기 위하여 기체 투과도가 서로 다른 포장재 LDPE, CPP, PD900, MPD2055, SM60에 열처리한 채소를 포장한 후 1$0^{\circ}C$에서 4주간 저장을 하였다. 포장 표면에 5mm의 구멍을 뚫은 대조구와 핀홀이 있는 SM60은 저장 2주 이후 부터 중량감소가 심하게 일어났다. 깻잎은 포장내부의 $CO_2$ 농도가 높게 유지되는 CPP에 포장할 때, 저장 2주부터 $CO_2$ 장해로 인하여 표면의 갈변과 연화가 심하게 일어났으며, 풋고추는 저장 3주부터 표면의 색상이 약간 붉은 색을 나타내기 시작하였다. 열처리 풋고추와 깻잎을 MDPE 포장에 저장을 하면 각각 저장 4주와 3주까지는 시장품질의 한계선으로 신선도가 유지되었다. 그러나 대파는 포장 내부의 $CO_2$ 농도가 높은 CPP에 포장할 경우 발근이 억제되며 저장 4주까지 시장품질 이상을 유지하였다.

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A Study on the Correlation Analysis between the Daily Earthwork Volume and Fine Dust Concentration

  • Dong-Myeong, CHO;Ju-Yeon, LEE;Tae-Hwan, JEONG;Woo-Taeg, KWON
    • Journal of Wellbeing Management and Applied Psychology
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    • v.6 no.1
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    • pp.1-7
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    • 2023
  • Purpose: Fine dust is classified as a group 1 carcinogen and poses a significant environmental problem that urgently requires improvement to protect the environmental rights of citizens. Given the difficulty of implementing measures to reduce overseas sources of fine dust, it is essential to first devise specific measures to address domestic emission sources. As such, this study aims to analyze the correlation between earthwork volume control and fine dust concentration as preliminary management measures to reduce the impact of scattering dust at construction sites. Based on real-time air quality information, field management measures will be presented to mitigate the effects of dust emissions. Research design, data and methodology: As examples, we selected construction sites that had recently undergone small-scale environmental impact assessment consultations. The standard earthwork volume was classified into grades using 20% intervals, and we applied AERMOD to predict the weighted concentration of fine dust based on the earthwork volume class and analyzed its correlation. Results: The results of this study demonstrate a strong correlation between earthwork volume and fine dust concentration. By utilizing the correlation analysis between earthwork volume and fine dust concentration on-site, this finding can be utilized as an effective fine dust management plan. Conclusions: This involves determining the daily earthwork intensity based on real-time air quality information and implementing measures to reduce scattering dust.

Effects of Partial Substitution of CeO2 with M2O3 (M = Yb, Gd, Sm) on Electrical Degradation of Sc2O3 and CeO2 Co-doped ZrO2

  • Shin, Hyeong Cheol;Yu, Ji Haeng;Lim, Kyoung Tae;Lee, Hee Lak;Baik, Kyeong Ho
    • Journal of the Korean Ceramic Society
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    • v.53 no.5
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    • pp.500-505
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    • 2016
  • Scandia-stabilized zirconia co-doped with $CeO_2$ is a promising electrolyte for intermediate temperature SOFC, but still shows rapid degradation during a long-term operation. In this study, $CeO_2$ (1 mol%) as a stabilizer is partially substituted with lanthanum oxides ($M_2O_3$, M=Yb, Gd, Sm) to stabilize a cubic phase and thus durability in reducing atmosphere. 0.5M0.5Ce10ScSZ electrolytes were prepared by solid state reaction and sintered at $1450^{\circ}C$ for 10 h to produce dense ceramic specimens. With addition of the lanthanum oxide, 0.5M0.5Ce10ScSZ showed lower degradation rates than 1Ce10ScSZ. Since $Gd_2O_3$ showed the highest ionic conductivity among the co-dopants, an electrolyte-supported cell with 0.5Gd0.5Ce10ScSZ was prepared to compare its long-term performance with that of 1Ce10ScSZ-based cell. Maximum power density of 0.5Gd0.5Ce10ScSZ-based cell was degraded by about 2.3% after 250 h, which was much lower than 1Ce10ScSZ-based cell (4.2%).

Effect of Induction Hardening on Mechanical Properties in Gas Nitrocarburized SM35C Steel (가스 침질탄화처리한 SM3SG강의 기계적 성질에 미치는 고주파퀜칭의 영향)

  • Kim, H.S.;Lee, K.B.;Yu, C.H.;Kim, H.T.;Jang, H.Y.
    • Journal of the Korean Society for Heat Treatment
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    • v.13 no.4
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    • pp.224-230
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    • 2000
  • Garbon steel(SM35C) was gas nitrocarburized at $580^{\circ}C$ in $55%N_2-40%NH_3-5%CO_2$ mixed gas atmosphere, and then the steel was induction hardened at $850^{\circ}C$. The microstructure of gas nitrocarburized surface layer was observed by optical microscope and SEM. The phase analysis was carried out by X-ray diffraction method. The mechanical properties of gas nitrocarburized SM35C steel was evaluated by hardness, wear and fatigue test. The thickness of compound and diffusion layer were increased with increasing the gas nitrocarburizing time and the densest compound layer was obtained at 3 hours gas nitrocarburizing time. In case of 15sec induction hardening after gas nitrocarburizing, the surface hardness was decreased from 800Hv to 630Hv owing to the decomposition of compound layer, but wear resistance was increased because of increased hardness of diffusion layer. The fatigue strength of induction hardened steel after gas nitrocarburizing, $58kgf/mm^2$, was higher than $41.5kg/mm^2$ of gas nitrocarburized steel and $45kg/mm^2$ of induction hardened steel, respectively.

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Prevalent Characteristics of Fowl Typhoid and Antibiotic Susceptibility of Salmonella gallinarum (닭 티푸스의 발생상황과 Salmonella gallinarum의 항균제 감수성)

  • 박노찬;도재철;조광현;장성준;권헌일;박덕상
    • Korean Journal of Veterinary Service
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    • v.18 no.2
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    • pp.113-123
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    • 1995
  • The present study was conducted to investigate the prevalent characteristics of Fowl Typhoid and antibiotic susceptibility of Salmonella gallinarum isolated from 56 infective or dead chickens of 20 egg laying farms in Kyung Buk province during the period from August to December 1994. 1. Among 416, 000 chickens of 92 flocks in 20 egg laying farms, 17, 360 chickens of 31 flocks were died of Fowl Typhoid. 2. Salmonella gallinarum was isolated from 56 chickens in liver and spleen, and then blood of infective chickens was positive to Pullorum antigen. 3, In the survey of gross lesion of 56 chickens, 43 chickens(76.8%) were swelled at liver, 39(69.6%) were swelled at spleen, 12(21.4%) were changed with bronze, 3(5.4% ) were hemorrhagic in peritoneal cavity. 4. In transmission pattern, 4 farms were outbreaked the entrance of chicken house at first, but the others were outbreaked at various place. They were transmitted at right and left directions in flock. 5. 2 farms confirmed at the early stage of infection were eradicated by removing infective chickens and administrating antibiotics, but 18 farms at chronic stage were not. 6. The biochemical properties of 112 Salmonella gallinarum from chickens were generally identical to those of the referance, but H$_2$S was not productive, cellobiose was fermentive. 7 Minimum inhibitory concentration(MIC) of 20 isolates was performed by using 21 antibiotics, MICs of Amikacin(Ak), Gentamicin(Gm), Kanamycin(Km), and Tetracycline (Tc) were below 1.6 ug/ml, Ampicillin(Am), Furazolidone(Fu) and Neomycin(Nm) were below 3.1 ug/ml, Cephalothin(Ce), Cefazoline(Cf) and Chloramphenicol(Cm) were below 6.3 ug/ml, Nalidixic acid(Na), Polymyxin(Po) and Rifampicin(Rf) were below 12.5 ug/ml, Penicillin (Pm) was below 25 ug/ml, Colistin(Co) and Streptomycin(Sm) were below 50 ug/ml, Sulfamerazine(Sr) and Sulfamethazine (St) were below 200 ug/ml, Lincomycin(Lm) and Spiramycin(Sp) were below 400 ug/ml, Bacitracin(Ba) was below 800 ug/ml. 8. Among the 20 isolates, all(100%) of those were sensitive to Ak, Am, Ce, Cf, Cm, Fu, Gm, Km, Na, Nm, Po, Rf, Sr, St and Tc, but 6 isolates(30%) were resistent to Co, 20(100% ) to Ba, Lm, Pm, Sm, and Sp. The drug resistance patterns were simple which 6 strains were BaCoLmPmSmSp type, and 14 were BaLmPmSmSp type.

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