• 한국유기농업학회지
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• 제20권4호
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• pp.475-490
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• 2012

Since 1997, Korean Ministry of Knowledge Economy and Ministry of Environment have established data on some 400 basic raw and subsidiary materials and process like energy, petro-chemical, steel, cement, glass, paper, construction materials, transportation, recycling and disposal etc by initiating establishment of LCI database. Regarding agriculture, Rural Development Administration has conducted establishment of LCI database for major farm products like rice, barley, beans, cabbage and radish etc from 2009, and released that they would establish LCI database for 50 items until 2020 later on. The domestic LCI database for seeds, seedling, agrochemical, inorganic, fertilizer and organic fertilizer etc is only at initial stage of establishment, so overseas LCI databases are brought and being used. However, since the domestic and overseas natural environments differ, they fall behind in reliability. Therefore, this study has the purpose to select organic farming materials, survey the production process for various types of organic farming materials and establish LCI database for the effects of greenhouse gas emitted by each crop during the process. As for selecting methods, in this study organic farming materials were selected in the method of direct observation of material and bottom-up method a survey method with focus on the organic farming materials admitted into rice production. For the basic unit of carbon emission amount by the production of 1kg of organic farming material, the software PASS 4.1.1 developed by Korea Accreditation Board under Ministry of Knowledge Economy was used. The study had the goal to ultimately provide basic unit to calculate carbon emission amount in executing many institutions like goal management system and carbon performance display system etc in agricultural sector to be conducted later on. As a result, emission basic units per 1kg of production were calculated to be 0.04968kg-$CO_2$ for oystershells, 0.004692kg-$CO_2$ for expanded rice hull, and 1.029kg-$CO_2$ for bordeaux mixture liquid.

• 한국도로학회논문집
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• 제19권6호
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• pp.105-115
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• 2017

PURPOSES : The occurrence of unexpected disasters, including fire events, increases as the road network becomes complicated and traffic volume increases. When a fire event occurs on and under bridges, the damage extensively influences direct damage to structures, vehicles, and human life and secondary socioeconomic issues owing to traffic blockage. This study investigated potential fire-hazard risks on bridges of the Korean national route road. METHODS : The investigation was conducted using field investigation and analysis with satellite pictures and road views from commercial websites and the Bridge Management System (BMS). From the filed investigation, various potential fire resources were identified. The satellite pictures and road views were helpful in measuring and recognizing conditions underneath bridges, stowage areas, etc. RESULTS : There are various potential fire resources underneath bridges such as piled agricultural products, parked petroleum tanks, construction equipment, and attached high-voltage cables. A total of 94.6% of bridges have underneath clearances of less than 15 m. A bridge underneath volume that can stow a potential fire hazard resource was $7,332m^3$ on average, and most bridges have about $4,000m^3$ of space. Based on the BMS data, the amounts of PSC and steel girders were 29% and 25%, respectively. CONCLUSIONS : It was found that the amount of stowed potential fire hazard resources was proportional to the underneath space of bridges. Most bridges have less than 15 m of vertical clearance that can be considered as a critical value for a bridge fire. The fire risk investigation results should be helpful for developing bridge fire-protection tools.

• Journal of Welding and Joining
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• 제26권6호
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• pp.81-91
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• 2008

The weldability of resistance spot welding of TRIP1180 steels for automobile components investigated enhance in order to achieve understanding of weld fracture during tensile-shear strength (TSS) test. The main failure modes for spot welds of TRIP1180 steels were nugget pullout and interfacial fracture. The peak load to cause a weld interfacial failure was found to be related to fracture toughness of the weld and the weld diameter. Although interfacial fracture occurred in the spot welded samples, the load-carrying capacity of the weld was high and not significantly affected by the fracture mode. Substantial part of the weld exhibits the characteristic dimple (or elongated dimple) fractures on interfacial fractured surface also, dimple fracture areas were drawmatically increased with heat input which is propotional to the applied weld current. In spite of the high hardness values associated with the martensite microstructures due to high cooling rate. The high load-carrying ability of the weld is directly associated with the area of ductile fracture occurred in weld. Therefore, the judgment of the quality of resistance spot welds in TRIP1180 steels, the load-carrying capacity of the weld should be considered as an important factor than fracture mode.

• Corrosion Science and Technology
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• 제16권6호
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• pp.285-293
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• 2017

The effects of sulfate reducing bacteria (SRB) on the corrosion and scaling of the Q235 carbon steel has been investigated in the simulated sewage water and oil field gathering pipelines production water, using scanning electron microscopy (SEM), energy dispersive x-ray spectrometry (EDS), and three-dimensional stereoscopic microscope. Results indicated that the concentration of SRB reached the maximum value on the ninth day in simulated sewage water with a large amount of scaling on the surface of specimen. In oil field gathering pipelines, a large amount of scaling and mineralization of mineral salts and thick deposition of extracellular polymeric substance (EPS) layers were also observed on the surface of specimen. The thickness of biofilm was about $245{\mu}m$ within 30 days. After adding microbicides, the thickness of corrosion products film was only up to $48-106{\mu}m$ within 30 days, suggesting that SRB could induce biomineralization. Under-deposit corrosion morphology was uniform in the absence of microbicides while local corrosion was observed in the presence of microbicides.

• 한국재료학회지
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• 제23권2호
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• pp.128-134
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• 2013

A study on the corrosion behavior of Inconel alloys and Incoloy 800H in molten salt of LiCl-$Li_2O$ was investigated at $650^{\circ}C$ for 24-312 hours in an oxidation atmosphere. The order of the corrosion rate was Inconel 600 < Inconel 601 < Incoloy 800H < Inconel 690. Inconel 600 showed the best performance suggesting that the content of Fe, Cr and Ni are the important factor for corrosion resistance in hot molten salt oxidation conditions. The corrosion products of Inconel 600 and Inconel 601 were $Cr_2O_3$ and $NiFe_2O_4$, In case of Inconel 690, a single layer of $Cr_2O_3$ was formed in the early stage of corrosion and an outer layer of $NiFe_2O_4$ and inner layer of $Cr_2O_3$ were formed with an increase of corrosion time. In the case of Incoloy 800H, $Cr_2O_3$ and $FeCr_2O_4$ were observed. Most of the outer scale of the alloys was observed to be spalled from the results of the SEM analysis and the unspalled scale which adhered to the substrate was composed of three layers. The outer layer, the middle one, and the inner one were Fe, Cr, and Ni-rich, respectively. Inconel 600 showed localized corrosion behavior and Inconel 601, 690 and Incoloy 800H showed uniform corrosion behavior. Ni improves the corrosion resistance and too much Cr and/or Fe content deteriorates the corrosion resistance.

• 한국재료학회지
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• 제8권6호
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• pp.571-576
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• 1998

본 연구에서는 용융탄산염 연료전지용 분리판으로서 오스테나이트계 스테인레스강 중, 310S를 사용하여 용융염 전해질 및 양극측 분위기에서 부식거동, 부식생성물의 형성과정 및 기구에 관한 고찰을 실시하였다. 분리판의 부식 진행과정은 부식반응 이후 안정 부식생성물이 형성되기까지 빠른 부식이 진행되는 부식생성물 형성단계와 안정 부식생성물 형성 후 보호파괴가 일어나기 까지의 부식 억제단계, 그리고 보호파괴 이후 부식이 다시 증가되는 부식 진행단계의 3단계 과정을 경유하며 진행하였다. 분리판 내 원소들의 농도분포는 부식생성물 형성영역에서는 Fe가, 부식 방어영역에서는 Cr이, 그리고 Ni은 Cr 고갈영역과 기지 안쪽에서 높게 형성되었다. 또한 양극측에서 분리판은 전해질의 이온화에 의한 부식이 주된 부식기구였으며, 최종 부식생성물은 $LiFeO_2$와 $LiCrO_2$였다.

• 한국식품저장유통학회지
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• 제22권1호
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• pp.154-157
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• 2015

신선편이용 절단배추의 선도유지 및 갈변 방지 목적으로 질소 치환 및 세라믹 칼날에 의한 절단 효과를 조사하였다. 저장 5일 이후부터 대조구에 비하여 NC 처리구의 중량변화와 갈변도가 적게 나타났다. 질소 치환과 세라믹 칼날의 사용에 의한 절단 공정의 개선이 절단채소의 선도 유지와 갈변 방지에 효과가 있을 것으로 생각된다.

• 한국건설순환자원학회논문집
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• 제3권2호
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• pp.171-179
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• 2015

최근 건설산업에서는 천연 골재 고갈과 엄격한 환경 규제로 인하여 골재 부족 현상이 지속되고 있기 때문에 대체 골재 개발이 시급한 실정이다. 따라서 본 연구에서는 기존 전로슬래그 처리방식의 문제점을 해결하기 위한 새로운 처리방식 즉, 고온 용융슬래그를 회전식 드럼내에 투입한 다음 냉각수, 압축공기 및 강철구를 이용하여 급속 냉각, 파쇄 처리하는 공정에서 발생되는 습식 급랭 전로슬래그를 콘크리트용 잔골재로 활용하기 위하여 기초물성을 검토하였다. 또한 본 연구를 통하여 콘크리트용 잔골재로써 습식 급랭 전로슬래그의 활용 방안을 제안하고자 한다.

• 한국표면공학회지
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• 제11권1호
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• pp.5-13
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• 1978

本 실험에서는 熔融亞鍍金工程에서 다른 諸要因을 一定하게 하고 鋼金溫度와 浸積時間에 따른 亞鉛附着量과 銑損失을 組織학的인 면에서 考察하였다. 銑損失에 要하는 活性化에너지를 구하였으며 試料範위內에서 附着量에 미치는 최적조건을 찾으므로서 不당한 銑損失을 막고 亞鉛原단位를 줄이는데 目的이 있다. 銑損失量과 드로스(Dross)발생량이 상호 密接한 關係에 있으며 도로스 발생량이 감소되면 亞鉛原단位가 감소되었다. 실驗結論은 다음과 같다. 1. 同一時間內에서 詩片-I은 470$^{\circ}$까지 도금층 두께 형성이 온도에 비례하며 浸積時間 8分정도에서 最大값을 나타낸다. 2. 詩片-5는 浸積時間에 比例해서 附着量이 급증함을 나타내었는데 이는 Si의 영향이 지배적이며 그 이외의 試料에서는 20分이후 附着量增加率이 극히 적었다. 浸積時間은 20分이 가장 적당하며 더 이상 오해 浸積시키면, 銑損失量만, 증가할 것이다. 3. 銑損失에 要하는 活性化에너지는 다음과 같으며 이와같은 값은 ${\gamma}$相의 成長에 미치는 活性化에너지 값과 거의 비슷하리라 생각됨. 詩片 - I = 18,500 Cal/mole 詩片 - III = 22,000 Cal/mole 詩片 - V = 42,300 Cal/mole

• 한국재료학회지
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• 제20권3호
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• pp.111-116
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• 2010

Chloride-based fluxes such as NaCl-KCl are used in the refining of Al melt. The vapor pressure of the chloride is one of the fundamental pieces of information required for such processes, and is generally high at elevated temperatures. In order to measure the vapor pressure for chlorides, the apparatus for the transpiration method was assembled in the present study. The vapor pressure of $ZnCl_2$ and $FeCl_2$, which is related with the process of aluminum refining and the recovery of useful elements from iron and steel industry by-products, was also measured. In the measurement of vapor pressure by the transpiration method, the powder of $ZnCl_2$ or $FeCl_2$ in a alumina boat was loaded in the uniform zone of the furnace with a stream of Ar. The weight loss of $ZnCl_2$ and $FeCl_2$ after holding was measured by changing the flow rate of Ar gas (10 sccm -230 sccm), and the partial pressures of $ZnCl_2$ and $FeCl_2$ were calculated. The partial pressures within a certain range were found to be independent of the flow rate of Ar at different temperatures. The vapor pressures were measured in the temperature range of 758-901K for $ZnCl_2$ and 963-983K for $FeCl_2$. The measured results agreed well with those in the literature.