• Title/Summary/Keyword: 건조 효율

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Strategy Planning of Digital Shipbuilding Simulation byWorkflow Analysis of Production Planning in a Shipyard (조선소 생산계획 업무 프로세스 분석을 통한 디지털 선박생산 시뮬레이션 적용 전략 수립)

  • Lee, Kwangkook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.8
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    • pp.1761-1768
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    • 2013
  • Digital shipbuilding is a technology to reduce the total cost and lead time inevitably made by reschedule and rework in a shipyard. Strategic planning should be undertaken in order to have an effect on the applicable field. We aim at planning a strategy of digital shipbuilding technology by analysis of production planning workflow in this paper. In the basis of BPR methodology, the as-is business process is analyzed to build an workflow model, and derive the bottleneck business process. We dig into the inside details of the process to illustrate an diagram of the core improvement opportunities, and perform process simulation not only to create the application scenarios but also to expect the main effects. The application strategy will make a basic sketch to save both the production cost and time for high quality products in the shipyards.

Reuse of Exhaust Heat and Improvement in Fuel Efficiency of Grain Dryer (곡물(穀物) 건조기(乾燥機)의 배기열(排気熱) 재이용(再利用) 및 열효율(熱効率) 개선(改善)에 관(關)한 연구(硏究))

  • Keum, Dong Hyuk;Lee, Yong Kook;Lee, Kyou Seung;Han, Jong Ho
    • Journal of Biosystems Engineering
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    • v.9 no.2
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    • pp.65-73
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    • 1984
  • While most of researches on the performance of high temperature grain dryer have dealt mainly with improving dryer capacity and drying speed during the last twenty years, energy efficiency, in fact, has not been emphasized. Current fuel supplies and energy cost have shifted the emphasis to reducing the energy consumption for grain drying while maintaining dryer capacity and grain quality. Since the energy input for drying is relatively large, the recovery and reuse of at least part of the exhaust energy can significantly reduce the total energy consumption in existing drying systems. Unilization of exhaust heat in grain dryer either through direct recycling or by a thermal coupling in heat exchanger have been subject of a number of investigators. However, very seldom research in Korea has been done in this area. Three drying tests(non-recycling, 0.22 recycle ratio, and 0.76 recycle ratio)were performed to investigate the thermal efficiency and heat loss factors of continuous flow type dryer, and to analyze the effect of recycle ratio (weight of exhaust air recycled/total weight of input air) on the energy requriements for rough rice drying. The test results showed that when the exhaust air was not recycled, the energy lost from furnace was 15.3 percent of input fuel energy, and latent and sensible heat of exhaust air were 61.4 percent and 11.2 percent respectively. The heat which was required in raising grain temperature and stored in dryer was relatively small. As the recycle ratio of exhaust air was increased, the drying rate was suddenly decreased, and thermal efficiency of the kerosene burner was also decreased. Drying test with 0.76 recycle ratio resulted in 12.4% increase in fuel consumption, and 38.4% increase in electric power consumption as compared to the non-recycled drying test. Drying test of 0.22 recycle ratio resulted in 6.8% saving in total energy consumption, 8.0% reduction in fuel consumption, and 2.5% increase in electric power consumption as compared to the non-recycled drying test.

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Preparation of Castable Refractories by Recycling of Aluminum Dross (알루미늄드로스를 재활용한 캐스타블내화물 제조)

  • Park Hyungkyu;Lee Hooin;Lee Jinyoung
    • Resources Recycling
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    • v.12 no.3
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    • pp.46-53
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    • 2003
  • Recycling of aluminum dross is an important issue in the secondary aluminum industries. In this study, aluminum dross generated in the domestic secondary aluminum industry was processed to use it as raw material for producing alumina refractories. Sample dross was classified according to its size. The dross smaller than 1 mm was leached with sodium hydroxide solution to extract the remained aluminum from the dross into the solution. and then aluminum hydroxide precipitate was recovered from the leach liquor. The waste residue in the leaching was washed, dried and roasted. Most remained metallic components in the residue was changed into oxide through the processes. The roasted dross was made into alumina castable refractories by mixing with aggregates and a binder. Bending strength of the tested castable specimen was over $25\;kg/\textrm{m}^2$ and compressive strength over $80\;kg/\textrm{cm}^2$, which satisfied the Korean Standard value respectively. From the results, it was suggested that this process could be applicable to recycling of aluminum dross.

Hydrological variability in the Han River basin during different phases of El Ni$\tilde{n}$o (서로 다른 엘니뇨 형태에 따른 한강유역의 수문학적 변동성 분석)

  • Kim, Jong-Suk;Yoon, Sun-Kwon;Lee, Joo-Heon;Moon, Young-Il
    • Proceedings of the Korea Water Resources Association Conference
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    • 2012.05a
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    • pp.197-197
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    • 2012
  • 본 연구에서는 대기 순환패턴 및 수문 환경변화에 영향을 미치는 주요인자인 El Ni$\tilde{n}$o-Southern Oscillation (ENSO)의 서로 다른 형태인 Warm-pool (WP) El Ni$\tilde{n}$o, Cold-tongue (CT) El Ni$\tilde{n}$o에 따른 한강유역의 봄철 (March~May)과 여름철 (June~August) 강수 및 유출의 특성을 분석하였다. 봄철 강수량의 경우, WP El Ni$\tilde{n}$o 시기에 증가추세를 보이며, 강수의 변동특성 또한 크게 나타났다. 여름철 강수량의 경우, CT El Ni$\tilde{n}$o 시기에는 평년보다 대체로 건조한 경향을 보이나, WP El Ni$\tilde{n}$o 시기에는 유역 전체에서 습한 경향을 보였으며 강수의 변동성은 매우 작은 것으로 분석되었다. 봄철 유출량의 경우, CT El Ni$\tilde{n}$o 시기와 WP El Ni$\tilde{n}$o 시기에 모두 평년치보다 크게 나타났으며, WP El Ni$\tilde{n}$o 시기에 한강 남부 대부분 유역에서 유출량이 통계적으로 유의한 증가 경향을 보였다. 여름철 유출량의 경우, CT El Ni$\tilde{n}$o 시기에는 대부분 유역에서 평년치보다 감소하나 수문 변량의 변동성은 큰 것으로 분석되었다. WP El Ni$\tilde{n}$o 시기에는 거의 모든 유역에서 유출이 증가하는 것으로 나타났으며, 특히 13개 중권역에서는 유출의 변동성이 작고 통계적으로 유의한 증가패턴이 분석되었다. 따라서 본 연구는 서로 다른 두가지 형태의 El Ni$\tilde{n}$o패턴에 대하여 한강유역의 봄철과 여름철 수자원 변동성에 민감하게 영향을 미치고 있음을 확인하였으며 수자원의 효율적인 예측 및 관리와 안정적인 용수공급을 위한 수문기상인자와 수문자료간의 관계 규명에 유용하게 활용될 것으로 기대한다.

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Research Trend of Bio-oil Production from Biomass by using Fast Pyrolysis (바이오매스로부터 급속 열분해를 통한 바이오오일의 생산기술 연구동향)

  • Kim, Jae-Kon;Park, Jo Yong;Yim, Eui Soon;Ha, Jong Han
    • Journal of the Korean Applied Science and Technology
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    • v.31 no.3
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    • pp.453-465
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    • 2014
  • The paper provides a review on bio-oil production technology from biomass by using fast pyrolysis to use heating fuel, power fuel and transport fuel. One of the most promising methods for a small scale conversion of biomass into liquid fuels is fast pyrolysis. In fast pyrolysis, bio-oil is produced by rapidly heating biomass to intermediate temperature ($450{\sim}600^{\circ}C$) in the absence of any external oxygen followed by rapid quenching of the resulting vapor. Bio-oil can be produced in weight yield maximum 75 wt% of the original dry biomass and bio-oils typically contain 60-75% of the initial energy of the biomass. In this study, it is described focusing on the characterization of feedstock, production principle of bio-oil, bio-oil's property and it's application sector.

An Experimental Study on the Behavior of RC Beams Externally Bonded with FRPs Under Sustained Loads (지속하중을 받은 FRP 외부부착 보강 철근콘크리트 보의 거동 특성에 관한 실험적 연구)

  • Shim, Jae-Joong;Oh, Kwang-Jin;Kim, Yeon-Tae;Park, Sun-Kyu
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.1
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    • pp.125-132
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    • 2010
  • In the recent construction industry, an external strengthening method using fiber reinforced polymers has been widely used. Since reinforced concrete structures strengthened with fiber reinforced polymers are always under sustained loads, influence of creep and shrinkage on the structures is inevitable. Due to the creep and shrinkage, behaviors of the structures, such as deflection, deformation, recovery capability, strength and so on are also under the influence of creep and shrinkage. Thus, in order to estimate efficacy, creep recovery and residual strength of FRP strengthened RC beams, long-term flexural experiments and static flexural experiments were carried out. As the result of the experiments, FRP strengthened RC beams were very effective in terms of deflection control. Furthermore, the strengthened beams had higher immediate deformation recovery than immediate deformation. Through the static flexural experiments, it was shown that the CFRP strengthened beam had high residual strength. It seems that the sustained loads did not affect bond and residual strength of the beams.

Multivariate Drought Assessment Using Composite Drought Index (CDI(Composite Drought Index)를 이용한 다변수 가뭄 평가)

  • Yu, Ji Soo;Wassem, Muhammad;Kim, Tae Woong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2015.05a
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    • pp.603-603
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    • 2015
  • 모든 외재적 형식의 가뭄을 모니터링하고 예측 및 평가하기 위해서는 가뭄지수가 필수적 요소로써 이용된다. 일반적으로 가뭄지수는 단일지수(single index), 다중지수(multiple index), 복합지수(composite index)로 분류되며 대부분 강수량, 유출량, 토양 수분량 등과 같은 하나의 변수만을 사용하는 단일지수이다. 가뭄지수는 가뭄평가에 있어서 각각의 장단점이 있다. 하나의 변수를 사용하는 가뭄지수는 계산이 간편하지만 가뭄의 물리적 특성을 정확하게 반영할 수 없기 때문에 신뢰할 수 있는 가뭄평가에 충분하지 않다. CDI(Composite Drought Index)는 PDSI(Palmer Drought Index), ADI(Aggregate Drought Index), SWSI(Surface Water Supply Index)와 같은 다중지수의 개념을 착안하여 고안되었으며, 모든 가뭄 형태(농업적 수문학적 기상학적)와 관련된 강우량, 유출량, 정규식생지수(NDVI)를 변수로써 사용하였다. NDVI는 MODIS(Moderate resolution imaging spectroradiometer)에서 제공하는 16일 간격의 위성자료를 이용하여 계산되었고 이와 시간 스케일을 맞추기 위해 나머지 두 변수 또한 16일 시계열을 사용하였다. CDI는 (1)각 변수들의 시계열을 행렬로 나타내고 (2)이것을 정규화하여 무차원 행렬로 변환한 후 (3)연구 지역의 최고습윤상태(most wet condition) 및 최고건조상태(most dry condition)의 차이값을 기반으로 하여 산정된다. 본 연구에서는 상대적으로 다른 유역에 비해 장기적이고 연속적인 자료를 확보할 수 있으며 농경지와 산림지역 비율이 높은 낙동강 유역을 대상유역으로 설정하였으며, 2001-2013년 기간의 자료를 이용하였다. 그 결과 연구 기간 중 실제 발생했던 가뭄을 반영하는 것을 확인하였다. 또한 CDI는 다양한 변수의 활용으로 가뭄의 물리적 특성의 반영이 가능하며 연구 지역의 기상 조건에 직접적으로 관련된 결과를 나타낸다. 자료의 가용성에 따라 적용범위가 제한적일 수 있으나 입력값으로 사용된 변수와 시계열을 편의와 효율에 따라 유연하게 적용할 수 있다. 따라서 CDI는 농업적, 수문학적, 기상학적 가뭄의 모든 관점을 통합하는 실용적 가뭄지수로써 사용될 수 있는 가능성을 포함하고 있다.

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The Detection and Multiplicity of Entomopathogenic Nematodes Using Silkworms (Bombyx mori) (누에를 이용한 곤충병원성 선충의 검색 및 배양)

  • 한상미;이광길;여주홍;권해용;우순옥;이용우;백하주;한명세
    • Journal of Sericultural and Entomological Science
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    • v.45 no.2
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    • pp.103-107
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    • 2003
  • Entomopathogenic nematodes were isolated through the investigation in soils collected from cultivated and non-cultivated fields using silkworms (Bombyx mori) and Galleria mellonella trap. The detectable rate of entomopathogenic nematodes of silkworms trap was higher than the G. mellonella trap. This study indicates the detection of entomopathogenic nematodes from soils that silkworms are sensitive superior to the G. mellonella to entomopathogenic nematodes. The steinernema, rhabditidae, and diplogatroidae strains successfully cultured on the silkworms host as well as on artificial media. Reproductivity in the living silkworm larva and pupa was 1.5 to 3.5${\times}$ 10$\^$5/ nematodes per host However, G. mellonella could be multiplied less than 5${\times}$l0$\^$5/ nematodes. The dried pupa of the silkworm following mositurize was cultured 0.5 to 2${\times}$10$\^$5/) nematodes per host. The culture methods of the steinernema, rhabditidae, and diplogatroidae strains, using silkworm powder, extracted chicken intestine, and food waste fertilizer could be applicative, but rate of reproduction was low.

Shelf-Life Extension and Increase in Survivability of Probiotics Powder by Ultrasonic Treatment (초음파를 이용한 프로바이오틱스 분말의 유통기한 연장 및 생존율 증대 효과)

  • Hong, Dong-Ki;Jung, Seong-Eun;Lee, Myoung-Hee;Lee, Ho-Jin;Lee, Jae-Ho;Na, Guk-Nam;Choi, Il-Dong;Lee, Jung-Lyoul;Sim, Jae-Hun
    • Journal of Dairy Science and Biotechnology
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    • v.36 no.4
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    • pp.220-225
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    • 2018
  • The purpose of this study was to investigate the effect of ultrasonic treatment during probiotics production process on the shelf life and the survival rate. Once Lactobacillus plantarum and Bifidobacterium longum were cultured in edible culture medium, ultrasonic treatment was performed at 100 Hz for 1, 2, 5, 7, and 10 minutes. Ultrasonic-treated L. plantarum HY7715 and B. longum HY8001 were centrifuged, mixed with a cryoprotectant, and lyophilized. The prepared lactic acid bacteria powder was individually packaged. After 6 months, viable cell counts were measured separately under cold storage and room temperature. In vitro digestion experiments were performed to determine the survival rate at digestive tract. As a result, it was observed that shelf life and survival rate were increased compared to untreated control group.

A Study on Mechanical Properties of SM490-TMC Back Plate(40 mm) Steel by SAW Welding (SM490-TMC 후판(40 mm) 강재의 SAW 용접을 통한 기계적 특성 연구)

  • Lee, Soung-Jun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.3
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    • pp.88-93
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    • 2021
  • SAW (Submerged Arc Welding) is often used for ship construction or welding pressure vessels and involves spraying a flux in a powder form to a welding site to a certain thickness and continuously supplying electrode wires therein. This welding method enables high current welding up to 1,500 to 3,000 A. Arc efficiency is higher than 95% and the technique allows clean work as it creates less welding fume, which is composed of fine metal oxide particles, and the arc beam is not exposed. In this study, SM490C-TMC thick plates were heterogeneously welded by SAW. Mechanical properties of welds were measured, and welds were assessed macroscopically and for adhering magnetic particles. The following conclusions were drawn. Bending tests showed no spots exploded on sample surfaces or any other defect, and plastic deformation testing confirmed sufficient weld toughness. These results showed the 1F welding method has no shortcomings in terms of bending performance.