• 제목/요약/키워드: Accelerating Degradation

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노후된 공작기계의 재제조에 관한 연구 (A Study on the Remanufacturing of Used Machine Tools)

  • 노영화
    • 한국산업융합학회 논문집
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    • 제23권3호
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    • pp.403-410
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    • 2020
  • Continuous industrial development has led to a better quality of life for everyone, even further accelerating industrial growth. Industrial development, however, has also caused environmental degradation, which is posing a serious threat to humanity. It has also encouraged the indiscriminate use of limited resources, causing resource depletion. Efficient resource management based on resource circulation is critical to saving resources. Resource circulation methods are as follows: reducing the use of resources in the manufacturing process, recycling used or reprocessed products and reusing used resources without being reprocessed, remanufacturing with end-of-life products with disassembled parts. Furthermore, remanufacturing process including cleaning, inspection, repairing, and reassembling facilitate performance level as well as new typical products. It is noteworthy that the remanufacturing of machine tools can significantly save resources because their structural parts are substantially large in size. Machine tools have served as a foundation for the manufacturing industry, which has driven Korea's industrial development. Nevertheless, a few research has been reported for remanufacturing technology with used machine tools. Relevant research of developing a remanufacturing process chart and method is prerequisite for saving the resource and environments.

인공림의 황폐실태와 도시지역 홍수 위험성 증대에 대하여 (Degradation of Planted Forest and Flood Management in Urban Area)

  • 쯔치야 노부유키
    • 한국환경생태학회:학술대회논문집
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    • 한국환경생태학회 2009년 학술대회 논문집 2호
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    • pp.1-16
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    • 2009
  • Japan is one of the major forest-rich countries in the world with two thirds of its national territory covered with forests. The various functions of forests, including the prevention of global warming, conservation of national land, recharging of water resources, and maintenance of biotic diversity, play an important role in our safe, secure, and comfortable living. With the increasing national expectations on the role of forests to contribute to the prevention of global warming and "Accelerating forest carbon-sink measures to achieve Kyoto Protocol Commitment", it is necessary to make efforts toward a large-scale forest regeneration in order to secure an absorption of 13 million carbon tons through forest carbon sink for the achievement of the target of six percent reduction under the Kyoto Protocol. Most importantly, however, is to accelerate the measures for forests as absorption sources, including thinning and other forestry management activities. However, there is a situation, among others, where thinning is not implemented properly due to the decreased willingness of forest owners to manage forests, because of the long-term low demand for domestic lumber and lumber prices. In addition, forestry workers are aging and decreasing in number. Thus, the circumstances surrounding forestry are severe. It is necessary for the protection of our precious forests to make efforts to create and maintain forests with activities that involve citizens such as the "National Movement for Utsukushii Mori Zukuri(Fostering Beautiful Forests)".

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모래말뚝이 타설된 연약점토지반의 압밀정수결정에 관한 연구 (Study on Determining Consolidation Parameters of Soft Clay Ground improved by Sand Pile)

  • 유승경
    • 한국지반공학회논문집
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    • 제21권5호
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    • pp.45-50
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    • 2005
  • 최근에 샌드드레인공법이나 샌드콤팩션파일공법 등과 같이 모래말뚝을 이용한 연약점토지반 개량공법의 적용이 증가하고 있다. 이러한 공법들로 개량된 연약점토지반에서는 모래말뚝에 의한 압밀촉진효과를 기대 할 수 있는데 실무에서는 보통 Barren의 이론해 등과 같은 이론식을 이용하여 그 효과를 평가하고 있다. 그러나 이러한 이론식들은 복합지반의 비선형 체적압축거동과 압밀중의 투수계수 변화 현상을 고려할 수 없으며, 따라서 그 평가결과가 합리적 이라고 판단하기 힘들다. 본 연구에서는 일련의 수치해석을 실시하여 Barren의 이론해에 적용되는 복합지반의 압밀정수 결정법에 대하여 고찰하였다. 수치해석 결과의 분석을 통하여 압밀 중에 변화하는 점토부의 체적압축거동특성과 투수성의 변화특성을 고려한 압밀정수의 결정방법을 제안하였다.

Study on analog-based ex-core neutron flux monitoring systems of Korean nuclear power plants for digitization

  • Kim, Young Baik;Vista, Felipe P. IV;Chong, Kil To
    • Nuclear Engineering and Technology
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    • 제53권7호
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    • pp.2237-2250
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    • 2021
  • The analog-based Ex-core Neutron Flux Monitoring System (ENFMS) in Korean Nuclear Power Plants (NPPs) has been performing its intended functions successfully for a long time. On the other hand, the primary concern with the extended use of analog systems is the aging effect, such as mechanical failures, environmental degradation, and obsolescence. The transition to a digital-based Man-Machine Interface Systems (MMIS) in Korea and other countries has been accelerating, but some systems are still analog-based IC systems, such as the ENFMS in APR1400 NPPs. Digitalized ENFMS can become a reality using computers and microprocessors owing to the progress in digital electronics and information technology. This paper presents the result of the first phase of the research on the digitalization of the ENFMS signal processing electronics for NPPs operated or produced in Korea. It has two main parts: (1) review engineering bases of ex-core neutron flux monitoring system, including nuclear engineering, instrumentation techniques, and analog and digital signal processing techniques, and (2) analysis of analog signal processing electronics of ENFMS for OPR1000 and APR1400 power plants. They are prerequisite to the second phase of the research which is the detailed implementation of the digitalization.

The Impact of Globalization on CO2 Emissions in Malaysia

  • CHUAH, Soo Cheng;CHEAM, Chai Li;SULAIMAN, Saliza
    • The Journal of Asian Finance, Economics and Business
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    • 제9권5호
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    • pp.295-303
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    • 2022
  • This study investigates the impact of globalization, coal consumption, and economic growth on CO2 emissions in Malaysia by applying the Kuznets Environmental Curve model. The study employed the Autoregressive Distributed Lag modeling technique on time series data over the period of 1970-2018 to determine the short and long-run relationship between CO2 emissions and a number of variables, including globalization, coal consumption, and economic growth. The results show that globalization increase CO2 emissions in both the short and long run in Malaysia. Furthermore, the results reveal that economic growth and coal consumption degrade the environmental quality by accelerating the CO2 emissions in the short-run and long run. As a result, the findings validate the Kuznets Environmental Curve hypothesis of an inverted U-shaped relationship between economic growth and CO2 emissions in the long run for Malaysia. The findings of this study suggest that higher globalization levels and usage of coal consumption degrade the environmental quality in Malaysia. The findings also indicate the effect of economic growth on environmental degradation is positive at the initial stage but improves after the economy achieves a threshold level of income per capita in the economic development process with an inverted U-shaped pattern in the long run.

ESG 실천 방안으로서의 컨셔스 패션(Conscious Fashion)의 국내 패션 사례 연구 (A Study on National Fashion Cases of Conscious Fashion as an ESG Practice)

  • 박희정
    • 패션비즈니스
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    • 제27권5호
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    • pp.13-25
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    • 2023
  • The implementation of ESG practices in the fashion industry has been accelerating, and its significance has been growing across all industries. This paper aims to examine the strategies for ESG implementation in domestic fashion brands and analyze how ESG principles are applied in the context of domestic conscious fashion. To analyze conscious fashion as a means of ESG implementation, the evaluation criteria of ESG from the Textile Fashion Policy Research Institute were utilized as analytical tools. As a result, five categories of domestic conscious fashion emerged: animal-free vegan fashion, eco-friendly plant-based vegan materials, upcycled fashion, regenerated fiber fashion utilizing waste materials, and fair trade fashion. The characteristics of these ESG practices in conscious fashion were identified with four key features. Firstly, the adoption of environmentally friendly materials demonstrates a tendency towards resource conservation, minimizing environmental degradation, and protecting ecosystems. Secondly, technology-driven circular practices are predominant in vegan and upcycled types, evident in the development of fashion materials and secondhand content. Thirdly, design practices based on scarcity incorporate characteristics of upcycling and fair trade. Lastly, the practices of social and ethical values underlie the philosophies of three types of conscious fashion. With the acceleration of ESG practices in the fashion industry and the increasing importance thereof, it is expected that domestic conscious fashion in South Korea will diversify in the future.

식물성(植物性) 색소(色素)의 이용(利用)에 관(關)한 연구(硏究) -II. 꽃잎맨드라미(Amaranthus tricolor L.) Anthocyanin색소(色素)의 안정성(安定性)- (Studies on the Utilization of Plant Pigments -II. Stability of Anthocyanin Pigments in Ganges Amaranth-)

  • 김광수;이상직;윤태헌
    • 한국식품과학회지
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    • 제11권1호
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    • pp.42-49
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    • 1979
  • 꽃잎맨드라미 anthocyanin을 식용색소(食用色素)로 이용할 목적으로 모델시스템하에서 anthocyanin 안정성(安定性)에 미치는 온도, pH, 당류(糖類) 및 그 분해산물(分解産物), ascorbic acid, quercetin, sodium pyrophosphate, thiouea 그리고 금속(金屬) 이온들의 영향을 조사한 결과는 다음과 같다. 1. pH가 8.0에서 1.0으로 낮아짐에 따라 anthocyanin의 파괴(破壞)가 지연되였는데 pH 2.0에서는 초기의 anthocyanin 파괴(破壞)가 pH 2.0, 3.0에서 보다 더 빨랐다. 2. 수용액내에서 가열 $(80^{\circ}C)$시 pH 2.0에서의 anthocyanin잔존량(殘存量)이 다른 pH수준에서보다 더 많았으며 저장온도가 상승함에 따라 색소(色素)의 파괴(破壞)가 크게 촉진되었는데 $40^{\circ}C$의 암소(暗笑)에서 10일후 19%정도 $2^{\circ}C$에서는 90%정도 남아 있었고 $2^{\circ}C$에서의 반감기(半減期)는 63일이었으나 $40^{\circ}C$에서는 1.7일로 떨어졌다. 이 색소파괴(色素破壞) 반응(反應)의 활성화(活性化)에너지는 18.93kcal/mole였다. 3. AA의 농도가 15 mg/100 ml에서 50 mg/100 ml로 증가함에 따라 반면에 색소잔존량(色素殘存量)은 줄어 들었다. 4. Anthocyanin의 파괴(破壞)에 대한 glucose와 fructose영향사이에 뚜렷한 차이가 없었으며 당류분해물(糖類分解物)중에서는 formic acid, levulinic acid, furfural 순으로 색소잔존율(色素殘存率)이 감소하였으며 furfural anthocyanin 파괴작용(破壞作用)이 가장 심하였다. 5. Ascorbic acid 공존하(共存下)에서 quercetin, sodium pyrophosphate 다같이 anthocyanin에 대한 보호작용을 인정할 수 없었으나 thiourea가 50 및 100 mg/100 ml인 처리구에서는 색소손실량(色素損失量)이 상당히 줄어 들었다. 6. 금속(金屬) 이온들중 $Hg^{2+}$$Cu^{2+}$은 30 ppm에서 기타 금속(金屬)이온들에 비하여 anthocyanin의 파괴(破壞)를 촉진시켰다.

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수렴성빔 전자회절법을 이용한 $SiO_2/Si$ 계면 부위의 격자 변형량 측정 (Measurements of Lattice Strain in $SiO_2/Si$ Interface Using Convergent Beam Electron Diffraction)

  • 김긍호;우현정;최두진
    • Applied Microscopy
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    • 제25권2호
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    • pp.73-79
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    • 1995
  • The oxidation of silicon wafers is an essential step in the fabrication of semiconductor devices. It is known to induce degradation of electrical properties and lattice strain of Si substrate from thermal oxidation process due to charged interface and thermal expansion mismatch from thermally grown SiO, film. In this study, convergent beam electron diffraction technique is employed to directly measure the lattice strains in Si(100) and $4^{\circ}$ - off Si(100) substrates with thermally grown oxide layer at $1200^{\circ}C$ for three hours. The ratios of {773}-{973}/{773}-{953} Higher Order Laue Zone lines were used at [012] zone axis orientation. Lattice parameters of the Si substrate as a function of distance from the interface were determined from the computer simulation of diffraction patterns. Correction value for the accelerating voltage was 0.2kV for the kinematic simulation of the [012]. HOLZ patterns. The change in the lattice strain profile before and after removal of oxide films revealed the magnitudes of intrinsic strain and thermal strain components. It was shown that $4^{\circ}$ -off Si(100) had much lower intrinsic strain as surface steps provide effective sinks for the free Si atoms produced during thermal oxidation. Thermal strain in the Si substrate was in compression very close to the interface and high concentration of Si interstitials appeared to modify the thermal expansion coefficient of Si.

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Effectiveness of Bioremediation on Oil-Contaminated Sand in Intertidal Zone

  • Oh, Young-Sook;Sim, Doo-Suep;Kim, Sang-Jin
    • Journal of Microbiology and Biotechnology
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    • 제13권3호
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    • pp.437-443
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    • 2003
  • Bioremediation technologies were applied to experimental microcosms, simulating an oil spill in a lower intertidal area. Three treatments (oil only, oil plus nutrients, and oil plus nutrients and microbial inocula) were applied, and each microcosm was repeatedly filled and eluted with seawater every 12 h to simulate tidal cycles. To minimize washing-out of the inoculum by the tidal cycles, microbial cells were primarily immobilized on diatomaceous earth before they were applied to the oiled sand. Oil degradation was monitored by gravimetric measurements, thin layer chromatography/flame ionization detector (TLC/FID) analysis, and gas chromatography (GC) analysis, and the loss of oil content was normalized to sand mass or nor-hopane. When the data were normalized to sand mass, no consistent differences were detected between nutrient-amended and nutrient/inoculum-amended microcosms, although both differed from the oil-only microcosm in respect of oil removal rate by a factor of 4 to 14. However, the data relative to nor-hopane showed a significant treatment difference between the nutrient-amended and nutrient/inoculum-treated microcosms, especially in the early phase of the treatment. The accelerating effect of inoculum treatment has hardly been reported in studies of oil bioremediation in the Tower intertidal area. The inoculum immobilized on diatomaceous earth seemed to be a very effective formulation for retaining microbial cells in association with the sand. Results of this study also suggest that interpretation of the effectiveness of bioremediation could be dependent on the selection of monitoring methods, and consequently the application of various analytical methods in combination could be a solution to overcome the limitations of oil bioremediation monitoring.

150℃에서 원전 2차측 배관재료의 Cr함량에 따른 유체가속부식 특성 (Effect of Cr content on the FAC of pipe material at 150℃)

  • 박태준;김홍표
    • Corrosion Science and Technology
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    • 제12권6호
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    • pp.274-279
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    • 2013
  • Flow accelerated corrosion (FAC) of the carbon steel piping in nuclear power plants (NPPs) has been major issue in nuclear industry. During the FAC, a protective oxide layer on carbon steel dissolves into flowing water leading to a thinning of the oxide layer and accelerating corrosion of base material. As a result, severe failures may occur in the piping and equipment of NPPs. Effect of alloying elements on FAC of pipe materials was studied with rotating cylinder FAC test facility at $150^{\circ}C$ and at flow velocity of 4m/s. The facility is equipped with on line monitoring of pH, conductivity, dissolved oxygen(DO) and temperature. Test solution was the demineralized water, and DO concentration was less than 1 ppb. Surface appearance of A 106 Gr. B which is used widely in secondary pipe in NPPs showed orange peel appearance, typical appearance of FAC. The materials with Cr content higher than 0.17wt.% showed pit. The pit is thought to early degradation mode of FAC. The corrosion product within the pit was enriched with Cr, Mo, Cu, Ni and S. But S was not detected in SA336 F22V with 2.25wt.% Cr. The enrichment of Cr and Mo seemed to be related with low, solubility of Cr and Mo compared to Fe. Measured FAC rate was compared with Ducreaux's relationship and showed slightly lower FAC rate than Ducreaux's relationship.