• 한국식품저장유통학회:학술대회논문집
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• 한국식품저장유통학회 2004년도 총회및 심포지움
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• pp.67-72
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• 2004

Quality of fresh-cut tomato slices was compared during cold storage under various modified atmosphere packaging conditions. Chilling injury of slices in containers sealed with Film A was higher than with Film B; these films had oxygen transmission rates of 87.4 and 60.0 ml $h^{-1}\;m^{-2}\;atm^{-1}$ at $5^{\circ}C\;and\;99\%$ RH, respectively. While slices in containers with an initial atmospheric composition of air, $4\%\;CO_2+1\;or\;20\%\;O_2,\;8\%\;CO_2+1\;or\;20\%\;O_2,\;or\;12\%\;CO_2+20\%\;O_2$ showed fungal growth, slices in containers with $12\%\;CO_2+1\%\;O_2$ did not. Low ethylene in containers enhanced chilling injury. Modified atmosphere packaging provided good quality tomato slices with a shelf-life of 2 weeks or more at $5^{\circ}C$. Experiments were conducted to compare changes in quality of slices of red tomato (Lycopersicon esculentum Mill. 'Sunbeam') fruit from plants grown using black polyethylene or hairy vetch mulches under various foliar disease management systems including: no fungicide applications (NF), a disease forecasting model (Tom-Cast), and weekly fungicide applications (WF), during storage at $5^{\circ}C$ under a modified atmosphere. Slices were analyzed for firmness, soluble solids content (SSC), titratable acidity (TA), pH, electrolyte leakage, fungi, yeasts, and chilling injury. With both NF and Tom-Cast fungicide treatments, slices from tomato fruit grown with hairy vetch (Vicia villosa Roth) mulch were firmer than those from tomato fruit grown with black polyethylene mulch after 12 days storage. Ethylene production of slices from fruit grown using hairy vetch mulch under Tom-Cast was about 1.5- and 5-fold higher than that of slices from WF and NF fungicide treatments after 12 days, respectively. The percentage of water-soaked areas (chilling injury) for slices from tomato fruit grown using black polyethylene mulch under NF was over 7-fold that of slices from tomato fruit grown using hairy vetch under Tom-Cast. When stored at $20^{\circ}C$, slices from light-red tomato fruit grown with black polyethylene or hairy vetch mulches both showed a rapid increase in electrolyte leakage beginning 6 hours after slicing. However, slices from tomato fruit grown using the hairy vetch mulch tended to have lower electrolyte leakage than those grown with black polyethylene mulch. These results suggest that tomato fruit from plants grown using hairy vetch mulch may be more suitable for fresh-cut slices than those grown using black polyethylene mulch. Also, use of the disease forecasting model Tom-Cast, which can result in lower fungicide application than is currently used commercially, resulted in high quality fruit for fresh-cut processing. Experiments were conducted to determine if ethylene influences chilling injury, as measured by percentage of slices exhibiting water-soaked areas in fresh-cut tomato slices of 'Mountain Pride' and 'Sunbeam' tomato (Lycopersicon esculentum Mill.). Ethylene concentration in containers without ventilation significantly increased during storage at $5^{\circ}C$, whereas little or no accumulation of ethylene occurred in containers with one or six perforations. Chilling injury was greatest for slices in containers with six perforations, compared to slices in containers with one perforation, and was over 13-fold greater than that of slices in control containers with no perforations. An experiment was also performed to investigate the effectiveness of including an ethylene absorbent pad in containers on subsequent ethylene accumulation and chilling injury. While ethylene in the no-pad controls increased continually during storage of both 'Mountain Pride' and 'Sunbeam' tomatoes at $5^{\circ}C$ under modified atmosphere conditions, no increase in accumulation of ethylene was observed in containers containing ethylene absorbent pads throughout storage. The ethylene absorbent pad treatment resulted in a significantly higher percentage of chilling injury compared with the no-pad control. In studies aimed at inhibiting ethylene production using AVG during storage of slices, the concentration of ethylene in control containers (no AVG) remained at elevated levels throughout storage, compared to containers with slices treated with AVG. Chilling injury in slices treated with AVG was 5-fold greater than that of controls. Further, we tested the effect of ethylene pretreatment of slices on subsequent slice shelf-life and quality. In slices treated with ethylene (0, 0.1, 1, or $10\;{mu}L\;L^{-1}$) immediately after slicing, ethylene production in non-treated controls was greater than that of all other ethylene pre-treatments. However, pretreatment of slices 3 days after slicing resulted in a different pattern of ethylene production during storage. Ihe rate of ethylene production by slices treated with 1 L $L^{-1}$ ethylene 3 days after slicing was greater during storage than any of the other ethylene treatments. With slices pre-treated with ethylene, both immediately and 3 days after slicing, the rate of ethylene production tended to show an negative correlation with chilling injury. Chemical name used: 1-aminoethoxyvinylglycine (AVG).

• 한국지반신소재학회논문집
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• 제6권2호
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• pp.27-32
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• 2007

본 연구에서는 절토사면 공법선정시 고려해야 할 영향인자에 대한 가중치 결정과 사면보강공법 선호도를 AHP기법을 이용하여 분석하였다. 연구, 설계, 시공업에 종사하고 있는 전문가를 대상으로 분석한 결과 공법선택시 안정성 및 내구성, 환경성이 가장 중요한 영향인자로 조사되었으며, 안전율 증가법 위주로 분석된 사면보강공법 선호도 조사에서는 경제성과 유지관리 용이성, 안정성에서 가장 우수한 평가를 받은 옹벽공법과 절토공법이 가장 선호도가 높은 공법으로 분석되었다.

• 한국환경복원기술학회지
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• 제5권4호
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• pp.70-79
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• 2002

This study was conducted to develop environmental restoration methods for the ecological restoration of the rock exposed steep cut-slopes using native woody plants seeds by the hydro-seeding with artificial soil media. The main results are summarized as follows; 1. Quercus spp. seeded after seed treatment germinated over 80% and most of them grew well until one year. So, Quercus spp. can grow at the extremely dry rock exposed slopes revegetated by hydro-seeding with soil-fertilizer-seed mixed media. 2. The germinated seedlings grew well at the slopes oriented southeast. But in case of the survival ratio of the germinated seedlings, northwestward slopes was the best. 3. In case of the using pot seedlings of the Miscanthus sinensis var. purpurascens, it shows more beautiful scenery than the area using cool-season grasses. 4. As the results of the experiment, Albizzia julibrissin, Quercus spp. and Lespedeza crytobotrya can be useful at the restoration and revegatation of the cut-slopes. 5. At the results of the seed mixture experiment, cool-season grasses covered the ground quickly, but slowly germinated Quercus spp. and Lespedeza crytobotrya formed under story vegetation. Also, Albizzia julibrissin formed upper story vegetation will be replaced by Quercus spp. slowly.

• 한국재료학회지
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• 제31권7호
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• pp.392-396
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• 2021

Expensive PCBN or ceramic cutting tools are used for processing of difficult-to-cut materials such as Ti and Ni alloy materials. These tools have the problem of breaking easily due to their high hardness but low fracture toughness. To solve these problems, cutting tools that form various coating layers are used in low-cost WC-Co hard material tools, and research on various tool materials is being conducted. In this study, binderless-WC, WC-6 wt%Co, WC-6 wt%Co-1 wt% Mo₂C, and WC-6 wt%Co-2.5 wt% Mo₂C hard materials are densified using horizontal ball milled WC-Co, WC-Co-Mo₂C powders, and spark plasma sintering process (SPS process). Each SPSed Binderless-WC, WC-6 wt%Co-1 wt% Mo₂C, and WC-6 wt%Co-2.5 wt% Mo₂C hard materials are almost completely dense, with relative density of up to 99.5 % after the simultaneous application of pressure of 60 MPa and almost no significant change in grain size. The average grain sizes of WC for Binderless-WC, WC-6 wt%Co-1 wt% Mo₂C, and WC-6 wt%Co-2.5 wt% Mo₂C hard materials are about 0.37, 0.6, 0.54, and 0.43 ㎛, respectively. Mechanical properties, microstructure, and phase analysis of SPSed Binderless-WC, WC-6 wt%Co-1 wt% Mo₂C, and WC-6 wt%Co-2.5 wt% Mo₂C hard materials are investigated.

• 한국연초학회지
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• 제21권2호
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• pp.144-151
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• 1999

This study was carried out to compare the change physico-chemical properties in the 10 grades of Burley leaf tobacco expanded by $CO_2$. The filling capacity of AB3T was increased from 5.44cc/g to 9.52cc/g with the expansion rate 75.0% and that of CD3W was increased from 5.57cc/g to 10.16cc/g with the expansion rate 82.4%. But the rate of cut tobacco longer than 3.36 mm decreased from 77.2% to 49.9% and from 67.3% to 41.2% in grade B1T and C1W, respectively. The contents of nicotine and total volatile base in the of expanded cut tobacco decreased 11.9% and 10.4% respectively. The contents of onganic acids, except oxalic and palmitic acid, essential oil, amino acids, nicotine, tar and ammonia contents in the cigarette smoke decreased by expansion procecs. These results suggest that expanded tobacco was very useful to make less irritative cigarettes.

• 한국화재소방학회논문지
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• 제17권4호
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• pp.28-35
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• 2003

선박기관실과 유사한 공간에 $CO_2$ 소화제를 방사하였을 때 화재위치에 따른 $CO_2$ 소화제 전달특성을 분석하기 위하여 전산묘사연구를 수행하였다. 화재위치를 변화시키면서 유동장과 농도장을 계산하였으며, 실험결과 화재화염위치가 유동패턴과 $CO_2$소화제 질량전달특성에 지배적인 영향을 미치는 것으로 나타났다. 1층과 2층으로 구성된 기관실의 2층 중앙 좌측영역에 화재화염이 위치하는 경우에는 에어 커턴과 같은 효과가 화재가 발생한 영역에서 나타났고, 이 영역으로의 질량전달을 방해하였다. 높이에 따른 특성에서는 1, 2충 중앙 좌측영역에 화재가 위치한 경우, $CO_2$소화제가 완전히 분사된 후에도 이 영역에 소화가능한계 이하의 등농도선이 형성되었다. 따라서 본 연구결과들은 $CO_2$소화장치 설비 시 $CO_2$소화제 분사노즐을 배열하는데 고려되어져야 할 것으로 생각된다.

• 한국기계가공학회지
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• 제19권12호
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• pp.42-48
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• 2020

Given the increasing interest in air pollution, several technologies to measure black carbon (BC) aerosol particles have been developed. As most BC aerosol particles are smaller than 1 ㎛, it is necessary to pre-separate the particles by size before a BC measuring instrument samples the aerosol particles. In this study, a miniature cyclone separator for portable BC measuring instruments was developed. A numerical approach was used to design the miniature cyclone separator with operating flow rates of 50, 100, or 150 mLPM, and then a prototype cyclone separator was manufactured for experimental validation. The numerical results of the cut-off size and pressure drop of the miniature cyclone separator agreed well with the experimental data. The cut-off sizes of the miniature cyclone separator were determined to be 2.9, 0.94, and 0.63 ㎛ for operating flow rates of 50, 100, and 150 mLPM, respectively. Thus, the miniature cyclone separator is suitable for use as a sampling inlet for the portable black carbon measuring instrument to sample BC aerosol or PM2.5 aerosol.

• 한국식품저장유통학회지
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• 제13권1호
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• pp.1-7
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• 2006

절단 양송이를 polyethylene film (PE), polypropylene film (PP), anti-fogging film (AF), perforated film (PF)을 사용한 일반 MA포장과, Nylon/PP film을 이용한 가스치환포장 (MA1, MA2) 및 진공(VF)포장 한 후 $5^{\circ}C$에 저장하면서 중량, 표면색, 페놀화합물, 비타민 C 및 관능적 품질 변화를 조사하였다. 저장 중 양송이의 호흡률은 절단 한 것이 절단하지 않은 것에 비하여 1.27배 높았다. 일반 MA포장내 산소가스농도는 밀봉 3일 이후 $1\~2\%$ 내외로 안정되었고, 탄산가스농도는 포장구에 따라서 $5\~15\%$ 내외로 유지되었다. 중량과 갈변도의 변화는 PP포장구에서 적었고, 경도는 PF포장구에서 가장 많이 변하였다. 유리 및 결합형 페놀화합물은 저장중 조금씩 감소하는 경향을 나타내었으며, PE포장구에서 변화가 가장 적었다. 비타민 C함량의 경우 PF포장구에서 가장 낮은 변화를 나타내었다. 관능적 품질 평가결과 저장 10일까지 MA2 포장구가 표면색 및 경도 측면에서 가장 우수하였으며, 그 다음으로 MA1, PE포장구 및 PP포장구였다. 본 연구결과, 전반적으로 MA2포장방법이 색, 경도, 비타민 C함량 및 관능적인 면에 있어 절단 양송이 저장방법으로 가장 우수한 양상을 나타내었다

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1161_1162
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• 2009

The recent environmental protection trend requires more strict energy saving, therefore every transportation system should reduce energy consumption to the minimum value. High-efficiency operation system, energy saving and $CO_2$ emissions shall be addressed as important issue in railway system. These issues are the most essential factors of railway, compared to major public transportation system. Recently, saving energy in the electric railway system has been studied. For such new energy saving, the energy storage system is considered for saving energy. Energy saving is possible by efficient use of regenerated energy. Regenerated energy is recycled amongst vehicles by mean of charge and discharge corresponding to powering and braking of electric vehicle operations. This energy saving contributes to cut $CO_2$ to reduce greenhouse gas emissions. Recycling regenerated energy demonstrate significant effect on peak cut of consumption energy in railway substation. Absorption of excess energy avoids regeneration failure due to high traction voltage. Therefore, the energy storage system is needed to be adopted to use regeneration energy when the vehicle is braking.

• 멤브레인
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• 제32권2호
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• pp.140-149
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• 2022

본 연구에서는 폴리술폰 분리막을 이용한 바이오가스 정제 공정으로 고선택성 소재를 이용한 2단 공정의 높은 회수율 및 경제성과 동등한 수준의 회수율을 확보하기 위해 저온 고압의 분리막 공정을 설계하고 평가하였다. 폴리술폰 고분자를 4성분계 도프를 이용하여 비용매 유도 상전이법으로 중공사 분리막을 제조하였다. 기체 분리용 중공사 분리막은 1.6 m²의 유효 막면적을 갖는 샘플을 제조하여 상온 및 저온에서 기체 투과 특성을 평가하였다. 제조된 기체분리막 모듈의 온도에 따른 기체 투과 특성을 분석하기 위하여 온도별 단일 기체 투과도를 평가한 결과 이산화탄소와 메탄 투과도는 20℃에서 각각 412, 12.7 GPU이며, -20℃에서는 각각 280, 3.6 GPU로써 이상 선택도는 32.4에서 77.8로 향상되었다. 단일 기체 투과 테스트 후 혼합 기체에 대한 분리 테스트를 진행하였으며, 모듈 1단 구성 및 2단 구성(막 면적비 1:1, 1:2, 1:3)을 통하여 투과 거동을 살펴보았다. 1단 구성에서는 stage-cut이 상승함에 따라 메탄의 농도가 상승하지만, 반대로 회수율은 떨어지는 결과를 나타내었다. 2단 구성 테스트에서는 메탄 농도 97% 기준에서 막 면적비 1:1보다 1:3이 메탄의 회수율이 더 높게 측정되었으며, 공급 기체의 온도가 낮을수록 메탄의 회수율이 높아짐을 확인하였고, 최종적으로 폴리술폰 2단 공정에서 메탄 농도 97%, 회수율 97%의 결과를 달성하였다.