• Title/Summary/Keyword: 충전층

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Development and Commercialization of Warm Covers Using Natural Fabric (천연 소재를 이용한 보온덮개 개발 및 사업화 방안)

  • Choi, Ju-Hyun;Beak, Hyun-Kuk;Cho, Yun-Jin
    • Journal of Convergence for Information Technology
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    • v.8 no.1
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    • pp.227-233
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    • 2018
  • The purpose of this study was to develop a warm cover for greenhouse with excellent thermal insulation and to propose ways of commercialization of the product. Feathers were used as filling materials because they formed the air layer to enhance insulation. Instead of downs for clothing or other textile products, we used disposed feathers. The developed product covers the outside of the greenhouse to keep the crops warm. It has multiple layers including feathers as filling materials, padding, inside fabric, heat insulation materials and outer fabric. It has proven to improve the insulation ratio. We developed other kinds of warm covers that are applicable to the inside of the greenhouse or the small houses in the greenhouse. Also, R&D system of educational industrial complex enables us to commercialize the products and building marketing strategies for them. This technology contributes to the expansion of energy-saving facilities for farmers, and it can serve the development and spread of various products utilizing feather.

The prediction for drying shrinkage of self-consolidating concrete using lightweight aggregate (경량골재를 사용한 자기충전 콘크리트의 건조수축률 예측)

  • Kim, Yong-Jic;Choi, Yun-Wang;Kim, Young-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.341-344
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    • 2008
  • Lightweight concrete is known for its advantage of reducing the self-weight of the structures, reducing the areas of sectional members as well as making the construction convenient. Thus the construction cost can be saved when applied to structures such as long-span bridge and high rise building. However, the lightweight concrete requires specific mix design method that is quite different from the typical concrete, since using the typical mix method would give rise the material segregation as well as lower the strength by the reduced weight of the aggregate. In order to avoid such problems, it is recommended to apply the mix design method of self-consolidating concrete for the lightweight concrete. Therefore experimental tests were performed as such mechanical properties(compressive strength, dry density and structural efficiency) of concrete and dry shrinkage according to ACI committee 209.

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Mechanical, Thermal and Electrical Properties of Polymer Nanocomposites Reinforced with Multiwalled Carbon Nanotubes (다중벽 카본나노튜브가 보강된 고분자 나노복합체의 기계적, 열적, 전기적 특성)

  • Kook, Jeong-Ho;Huh, Mong-Young;Yang, Hoon;Shin, Dong-Hoon;Park, Dae-Hee;Nah, Chang-Woon
    • Polymer(Korea)
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    • v.31 no.5
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    • pp.422-427
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    • 2007
  • Semiconducting layers are thin rubber film between electrical cable wire and insulating polymer layers having a volume resistivity of ${\sim}10^2{\Omega}cm$. Commercial semiconducting layers ire composed of polymer composites reinforced with more than 30 wt% of carbon blacks. A new semiconducting material was suggested in this study based on the carbon nanotube(CNT)-reinforced polymer nanocomposites. CNT-reinforced polymer nanocomposites were prepared by solution mixing and precipitation with various polymer type and dual filler system. The mechanical, thermal and electrical properties were investigated as a function of polymer type and dual filler system based on CNT and carbon black. The volume resistivity of composites was strongly related with the crystallinity of polymer matrix. With the decreased crystallinity, the volume resistivity decreased linearly until a critical point, and it remained constant with further decreasing the crystallinity. Dual filler system also affected the volume resistivity. The CNT-reinforced nanocomposite showed the lowest volume resistivity. When a small amount of carbon black(CB) was replaced the CNT, the crystallinity increased considerably leading to a higher volume resistivity.

EFFECT OF SOFT CHELATING IRRIGATION ON THE SEALING ABILITY OF GP/AH PLUS ROOT FILLINGS (Soft chelating irrigation이 GP/AH Plus로 충전된 근관의 sealing ability에 미치는 영향에 대한 평가)

  • Yu, Yi-Suk;Kim, Tae-Gun;Lee, Kwang-Won;Yu, Mi-Kyung
    • Restorative Dentistry and Endodontics
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    • v.34 no.6
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    • pp.484-490
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    • 2009
  • The purpose of this study was to evaluate the effect of soft chelating irrigant on the sealing ability of root fillings by using a glucose leakage test. A total of 45 single-rooted teeth were selected for the study. The teeth were decoronated leaving a total length of 13mm. The root canals prepared using K3 NiTi rotary instruments to an apical dimension of size 45(0.06 taper). The specimens were then randomly divided into 3 experimental groups of 13 roots each and 2 control groups of 3 roots each. Specimen in each group were prepared with different irrigation protocols : group 1, 2.5% NaOCl; group 2, 2.5% NaOCl and 17% EDTA: group 3, 2.5% NaOCl and 15% HEBP. The root canals were filled with gutta-percha and AH Plus sealer using lateral condensation. After 7 days in $37^{\circ}C$, 100% humidity, the coronal-to-apical microleakage was evaluated quantitatively using a glucose leakage model. The leaked glucose concentration was measured with spectrophotometry at 1, 4, 7, 14, 21 and 28 days. There was a tendency of increase in leakage in all experimental groups during experimental period. HEBP-treated dentin showed no significant difference with EDTA-treated dentin during experimental period. From the 21th day onward, HEBP-treated dentin showed significantly lower leakage than smear-covered dentin. HEBP-treated dentin displayed a similar sealing pattern to EDTA-treated dentin and a better sealing ability than smear-covered dentin. Consequently, a soft chelator(HEBP) could be considered as the possible alternative to EDTA.

Removal of Heavy Metal and Phenol from Aqueous Solution Using Fe(III) loaded Adsorbent (3가철 함유 흡착제를 이용한 수용액상의 중금속 및 페놀제거연구)

  • Kim, Seok-Jun;Kim, Won-Gee;Lee, Seung-Mok;Yang, Jae-Kyu;Lee, Nam-Hee
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.7
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    • pp.541-548
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    • 2009
  • Iron coated media (activated carbon, sand and starfish) were prepared at pH 4 and applied for the treatment of landfill leachate containing organic compounds and soluble metal ions such as $Zn^{2+},\;Cu^{2+},\;Mn^{2+}$ in batch and column experiment. The amount of iron coated in media was analyzed with EPA 3050B method. The removal efficiency of metal ions and phenol was compared with iron coated media. The amount of iron coated in Fe-AC and ICS(iron coated sand) were 1,612 mg/kg and 1,609 mg/kg, respectively, while it was higher with 1,768 mg/kg in ICSF(iron coated starfish). The result of batch study represent the highest removal efficiency in the treatment of wastewater using iron coated starfish. In column study, the removal efficiency of phenol and metal ions was higher in multi-layered system of ICS, Fe-AC and ICSF compared to single layered system. Breakthrough time in the effluent was relatively enhanced for $Cu^{2+}$ and $Zn^{2+}$ in multi-layered system while the removal efficiency of $Mn^{2+}$ were not varied much. Therefore, multi-layered system was identified as the better system for the treatment of wastewater containing of metal ions and organic compound.

Study on Optimum Mixture of Industrial By-Products for Lightweight Foamed Filler Production by Mixture Experimental Design (혼합물 실험계획법에 의한 경량기포 충전재 제조를 위한 산업부산물의 최적 배합 검토)

  • Woo, Yang-Yi;Park, Keun-Bae
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.1
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    • pp.37-43
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    • 2019
  • This research studied production of lightweight filling production for sink hole restoration utilizing various industrial by-products(2kinds of fly ash, petro-cokes CFBC ash, blast furnace slag fine particle). For this purpose, the mixed raw material properties(compressive strength) behaviors according to the blending ratio of industrial by-products were examined by applying the experimental design method and statistical analysis was performed using the commercial program MINITAB. Compressive strengths of industrial by-products were strongly dependent on blast furnace slag powder. Compressive strength(3days aging) was 3~11MPa depending on the amount of blast furnace slag powder used. The use of CFBC fly ash was evaluated to have the least effect on compressive strength. In addition, the compressive strength and the coefficient of permeability were measured by preparing foamed concrete for the experimental batch 1 condition in the mixture experimental design. In this case, the bulk density is 0.9 to 1.0, the apparent porosity is 30 to 50%, the compressive strength(3days old) is 1 to 2MPa, and the permeability coefficient is $10^{-2}$ to $10^{-3}cm/sec$.

Applied Mineralogy for the Conservation of Dinosaur Tracks in the Goseong Interchange Area (35번 고속도로 고성 교차로 지역 공룡발자국의 보존을 위한 응용광물학적 연구)

  • Jeong Gi Young;Kim Soo Jin
    • Journal of the Mineralogical Society of Korea
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    • v.17 no.3
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    • pp.189-199
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    • 2004
  • Cretaceous sedimentary rocks bearing dinosaur tracks in the Goseong interchange area were studied for their conservation and public display in the aspect of applied mineralogy. Black clay layers alternate with silt layers in the sedimentary rocks. The verical and horizontal fissures are commonly filled with calcite veinlets, supergenetic iron and manganese oxides. The rocks are composed of quartz, albite, K-feldspar, calcite, chlorite, illite, muscovite, and biotite, with minor apatite and rutile. Silt layers are relatively rich in calcite and albite, whereas clay layers are abundant in quartz, illite, and chlorite. Al, Fe, Mg, K, Ti, and P are enriched in the clay layers, while Ca, Na, and Mn in silt. Most of trace elements including V, Cr, Co, Ni, Cs, Zr, REE, Th, and U are enriched in clay layers. Inorganic carbon are present in silt layers as calcite, while organic carbon in black clay layers. The black clay layers were partly altered to yellow clay layers along the fissures, simultaneously with the decrease of organic carbon. Selective exfoliation of clay-rich black and yellow clay layers, calcite matrix of silt layers and calcite infillings of fissures are estimated as the major weakness potentially promoting chemical and physical degradation of the track-bearing rock specimens.

Microbial Desulfurization of Coal by Iron-Oxidizing Bacteria Thiobacillus ferrooxidans in packed beds (철산화 박테리아 Thiobacillus ferrooxidans를 이용한 충전탑 반응기에서의 석탄의 생물학적 탈황)

  • 류희욱
    • KSBB Journal
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    • v.14 no.1
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    • pp.124-130
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    • 1999
  • To evaluate the technical of microbial coal desulfurization during the storage in coal dumps, microbial pyrite oxidation in a packed column reactor with Thiobacillus ferrooxidans has been investigated. For microbial desulfurization in a packed reactor system, coal particle size over 1.0 mm with uniform size distribution seems to be most suitable as fas as drainage behavior and accessability of pyrite are concerned. When coal samples of 1∼2 and 2∼4 mm particle size were size were used, about 32∼42% of pyritic sulfur was removed within 70 days. The rate of pyritic sulfur oxidation was in the range of 348∼803 mg S/kg coal ·d, and the sulfur removal rates in packed columns were about 15∼25% of those in suspension cultures. Without any circulation of liquid medium, microbial coal desulfurization could be possible by the inoculation of T. ferrooxidans along on the coal dump. It was concluded that a microbial percolation process is one of possible processes for the desulfurization of high sulfur coal during a long-term storage.

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Improvement of Durability and Change of Pore Structure for Concrete Surface by the Penetrative Surface Protection Agent (함침계 표면보호제에 의한 콘크리트 표면의 세공구조 변화 및 내구성 향상)

  • Kang, Suk-Pyo;Kim, Jung-Hwan
    • Journal of the Korea Concrete Institute
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    • v.18 no.1 s.91
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    • pp.125-132
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    • 2006
  • Recently, surface finishing and protection materials were developed to restore performance of the deteriorated concrete and inhibiting corrosion of the reinforcing-bar. For this purpose, surface protection agent as well as coatings are used. Coatings have the advantage of low Permeability of $CO_2,\;SO_2$ and water. However, for coatings such as epoxy, urethane and acryl, long-term adhesive strength is reduced and the formed membrane of those is blistered by various causes. Also when organic coatings are applied to the wet surface of concrete, those have a problem with adhesion. On the other hand, surface protection agent penetrates into pore structure in concrete through capillary and cm make a dense micro structure in concrete as a result of filling effect. Furthermore, the chemical reaction between silicate from surface protection agent and cement hydrates can also make a additional hydration product which is ideally compatible with concrete body. The aim of this study is to examine the effect of penetrative surface protection agent(SPA) by evaluating several concrete durability characteristics. The results show that the concrete penetrated surface protection agent exhibited higher durability characteristics for instance, carbonation velocity coefficient, resistance to chemical attack and chloride ion penetration than the plain concrete. These results due to formation of a discontinuous macro-pore system which inhibits deterioration factors of concrete by changed the pore structure(porosity and pore size distributions) of the concrete penetrated surface protection agent.

양이온교환 수지층에서 V(III)-Fe(II)-Picolinate 착화물 함유 제염폐액의 재생연구(III);재생거동에 대한 공정변수의 영향

  • 심준보;박상윤;문제권;오원진;김종득
    • Proceedings of the Korean Nuclear Society Conference
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    • 1995.05b
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    • pp.921-927
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    • 1995
  • 수지충전식 전해재생조내에서 바나듐-철-Picolinate 착화물이 함유된 모의 LOMI 제염폐액의 재생거동에 대한 공정변수의 영향을 조사하였다. 전기투석에 의해 양이온종이 제염 폐액으로부터 제거되는 재생 분리효율에 대한 전류밀도, 제염폐액 공급유량 및 재생조내 수지층두께 등 공정변수의 영향은 바나듐이온이 가장 크게 받는다. 공정변수의 영향을 총괄 파라미터인 공정변수비 $\alpha$로 정의하여 나타낼 때 재생 분리효율 95%이상을 얻기 위해서는 $\alpha$가 0.2 이하로 유지되어야 한다. LOMI 제염폐액의 재생시 전기투석 flux는 공정변수비, $\alpha$값이 증가함에 따라 철이온이 바나듐이온에 비해 더욱 커지는 경향을 보였다. 재생종료 후 발생되는 음극폐액내 철 및 코발트 등 방사성이온종은 음극액의 초기 수소이온 농도를 조절하면 침전제의 첨가 얼이 음극반응에 의해 음극액의 pH를 산성에서 알카리성으로 바꿀 수 있어, 수산화물 형태의 침전물 입자로 만들어 쉽게 제거할 수 있다. 재생시 바나듐이온은 대부분 $V^{III}$(Pic)$_2$$^{+}$ 착화물형태로 전기투석된다. 음극액으로 formate용액을 사용하면 철 및 코발트 등 방사성이온종을 제거한 음극액은 농축된 LOMI제염제로 회수하여 필요시 산화가를 조정한 후 재생된 착화제와 혼합하여 제염제로 재사용할 수 있어, 더욱 효과적으로 제염폐액을 재생하는 향상된 재생방법이다.다.

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