• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.3
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• pp.152-159
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• 2010

Recently, the public interest in eco-friendly material and structure has been increasing and many Hwang-toh researches are being actively performed. Hwang-toh is one of the traditional environment friendly construction materials used as a construction and plastering material. Hwang-toh has many advantages as construction material due to its high heat storage capacity, auto-purification, antibiotic ability, and infrared ray emission characteristics. But, currently it has not been developed into construction material and used in modern construction due to its low strength and dry shrinkage cracking prone characteristics. According to the recent researches and study results, Hwang-toh can be used as a natural pozzolanic material like fly-ash or pozzolan. In this study, mechanical properties and structural flexure behavior experiments of slag, recycled PET fiber, and Hwang-toh added concrete are carried out. The test results showed that drying shrinkage of concrete mixed with Hwang-toh has lower compressive strength and elastic modulus than those of control cement concrete specimen, but it has the similar flexural behavior in reinforced concrete beams.

• Resources Recycling
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• v.28 no.4
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• pp.15-22
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• 2019

Coal combustion products are generated during coal combustion and can be grouped into fly ash and bottom ash depending on collection methods. Fly ash and bottom ash can be recycled for various purposes based on their characteristics. Australia is the fourth largest coal production country in the world and reuses coal ash as cement, concrete, mine filler, and agricultural soil amendment. When fly ash is used as a supplement for cement and concrete, strength of the cement and the durability of the concrete can be improved. Use of coal combustion product for mine backfill stabilizes underground mine voids and stores a large amount of coal ash in the voids. Because of alkalinity of coal combustion products, it can neutralize acid mine drainage when used for mine backfill. In addition, it can be used as an agricultural soil amendment to improve acidity and physical properties of the soil and to supply plant nutrients. Recycling of fly ash in Australia will be further expanded because of its low trace element contents that can be toxic to plants and low radioactive element contents existing within soil background concentrations. The characteristics of coal combustion products are related to the characteristics of the coal used for combustion, and since Korea imports coal from Australia, Korean coal combustion products also can be recycled for various purposes.

• Food Science and Preservation
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• v.10 no.4
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• pp.441-446
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• 2003

Cherry tomatoes, cucumbers and zuchinis stored in the far-infrared radiated chamber at 5$^{\circ}C$ or 10$^{\circ}C$ under 90% of relative humidity had been maintained in the fresh state for longer times than the control stored only in the cold chamber. Vegetables stored in the far-infrared radiated chamber showed lower values in weight loss rate, microbial colony count and decay ratio and higher ascorbic acid content than the control stored cold in the cold room through the storage period. We confirmed that vegetables stored in the far-infrared radiated chamber under low temperature and high humidity showed least changes in quality properties through the storage period and the far-infrared radiated facilities could be a good storage system.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.386-391
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• 2003

Ready mixed mortar has been originated from lime industry of Germany and is being used widely in the world at present. In recent years, the studies of mortar with new faculty have been progressed. In this study, we used elvan instead of using sand in order to make cement mortar and investigated characteristics of elvan and mortar that used elvan. The major compositions of elvan were $SiO_2$ and $Al_2O_3$. The crystal phases of elvan were composed of quartz and sillimanite. Elvan had a lot of pore and absorption ratio was 2.09%. The compressive strength of mortar that used elvan satisfied korean industrial standards under 1:3 (mixing ratio) and water retentivity increased according to increase of elvan contents. Far infrared radiation and deodorization ratio increased and thermal conductivity decreased according to increase of elvan contents.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.92-92
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• 2012

나노필라멘트 섬유는 직편물 등으로 구조/용도 다양화 가능하다. 나노필라멘트 섬유는 소재특유의 닦음성, 흡착성, 고밀도 특성 등을 활용하여 직편물의 형태로 다양한 용도 개발이 가능하며, 나노기술을 접목시킨 새로운 기능성과 고성능 섬유 소재 개발을 통한 자동차 분야의 개발 트랜드인 고급화, 경량화, 고성능화 추진을 위해 연료전지, 신슐레이터, 고성능 필터, 시트나 도어트림, 헤드라인과 같은 인테리어류와 전자 분야의 제조원가 절감, 공정 단순화를 위해 프린터 토너, 하드디스크 연마제, 다용도 No Dust Cleaner 등의 개발, 의료/바이오 분야의 혈액필터, 수술용 보호제, 창상억제제(유착 방지막), 항균마스크, 의료용 약물전달 시스템 및 환경 분야의 정수/공기 정화 시스템, 건축 토목용 보강제, 고(高)인성 콘크리트, 폐수처리용 슬러리 담체(Matrix) 등 다양한 분야로 용도 개발이 가능하다. 본 연구는 나노필라멘트의 다양한 분야로의 용도 개발 적용의 기초연구로서, 부직포 상으로 얻어지는 나노섬유 제조기술의 단점인 직경의 불균일, 물리적 특성의 한계와 필라멘트가 아닌 단섬유로 인해 발생하는 용도 및 상품 개발에의 제한성을 개선하기 위하여 연속적으로 필라멘트를 생산가능한 해도형 복합방사 방법을 도입하여 개발한 장섬유 필라멘트 형태의 해도형 나노 섬유 소재를 활용하는 것으로 방사된 SDY 형태의 나노필라멘트 섬유를 제직상에서의 작업성 용이 및 직물의 벌키성 증대와 Crimp성을 향상 시켜 터치감 및 후가공에 용이할 수 있도록 DTY를 제조함에 있어 기존 일반 POY사에서의 DTY공정과는 달리 소재의 특성 즉, 해도사의 해성분 및 도성분의 후공정을 감안하여 최적의 Crimp는 발현하되 단면의 형상을 유지할 수 있는 다양한 사가공 조건을 설정 하고 이에 따라 가공사를 생산하여 공정조건에 따른 가공사의 물성 및 수축특성을 비교 분석 하여 염색 및 후가공시 소재의 물성 및 수축특성이 미치는 영향성을 살펴보고자 하였다.

• Journal of Radiation Protection and Research
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• v.3 no.1
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• pp.29-32
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• 1978

A shielding calculation has been carried out for a storage vault of $5292(42{\times}42{\times}3)$ waste drums in which the mixed radioactive gamma-emitters are contained. The required ordinary concrete shielding thickness seems to be approximately 50cm. The results in terms of dose rate for polyenergy gammas appear to be considerably higher than those of the averaged energy gamma.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.1
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• pp.35-44
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• 2008

Long-term degradation of coment barrier by diffusion was studied with reactive transport modeling. The result of modeling showed that cement barrier was altered about 30cm thickness after 50,000 years. The pH decreased from 13.0 to 11.9 because of depletion of alkali ions, and dissolution/precipitation of portlandite and CSH (Calcium Silicate Hydrate). In addition, porosity increased about 0.3 because of dissolution of portlandite and $CSH2.0(Ca_2SiO_3(OH)_2:0.17H_2O)$. The solubility of uranium also increased with the increase of pe value The results of this study indicate that long-term degradation of comet can enhance the transport of nuclide by changing pH, pe, porosity in barrier.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.3
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• pp.219-230
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• 2017

This study was conducted to predict and evaluate the uncertainty of safety after closure of the second phase surface disposal facility of the Gyeongju intermediate and low level repository in Korea. In this study, four scenarios are developed considering both intact and degraded states of multi-layered covers and disposal containers; also, the fluid flow by a rainfall into the disposal facility is simulated. The rainfall conditions are implemented based on the monthly average data of the past 30 years (1985~2014); the simulation period is 300 years, the management period regulated by institutional provisions. As a result of the evaluation of the basic scenario, in which the integrity of both of the containers and the covers is maintained, it was confirmed that penetration of rainfall does not completely saturate the inside of the disposal facility. It is revealed that the multiple cover layers and concrete containers effectively play the role of barrier against the permeation of rainfall.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.4
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• pp.357-365
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• 2016

We observed the ${\gamma}-ray$ shielding characteristics and compressive strength of five types of concrete using general aggregates and high-weight aggregates. The aggregates were classified into fine aggregate and coarse aggregate according to the average size. The experimental results obtained an attenuation coefficient of $0.371cm^{-1}$ from a concrete with the oxidizing slag sand (OSS) and oxidizing slag gravel (OSG) for a ${\gamma}-ray$ of $^{137}Cs$, which is improved by 2% compared with a concrete with typical aggregates of sand and gravel. In the unit weight measurement, a concrete prepared by iron ore sand (IOS) and OSG had the highest value of $3,175kg{\cdot}m^{-3}$. Although the unit weight of the concrete with OSS and OSG was $3,052kg{\cdot}m^{-3}$, which was lower than the maximum unit weight condition by $123kg{\cdot}m^{-3}$, its attenuation coefficient was improved by $0.012cm^{-1}$. The results of chemical analysis of aggregates revealed that the magnesium content in oxidizing slag was lower than that in iron ore, while the calcium content was higher. The concrete with oxidizing slag aggregates demonstrated enhanced ${\gamma}-ray$ shielding performance due to a relatively high calcium content compared with the concrete with OSS and OSG in spite of a low unit weight. All sample concretes mixed with high-weight aggregates had higher compressive strength than the concrete with typical sand and gravel. When OSS and IOS were used, the highest compressive strength was 50.2 MPa, which was an improvement by 45% over general concrete, which was achieved after four weeks of curing.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.5
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• pp.535-542
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• 2015

A reactor containment acts as a final barrier to prevent leakage of radioactive material due to the possible reactor accidents into external environment. Because of the functional importance of the containment building, the SIT(Structural Integrity Test) for containments shall be performed to evaluate the structural acceptability and demonstrate the quality of construction. In this paper, numerical analyses are presented, which simulate the results obtained from the SIT for a prestressed concrete(PSC) structure. A sophisticate structural analysis model is developed to simulate the structural behavior during the SIT properly based on various preliminary analysis results considering contact condition among structural elements. From the comparison of the analysis and test results based on the acceptance criteria of ASME CC-6000, it can be concluded that the construction quality of the containment has been well maintained and the acceptable performance of new design features has been verified.