• 한국지반신소재학회논문집
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• 제14권2호
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• pp.71-79
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• 2015

기존의 비탈면녹화공법인 식생기반재취부공법은 결합력의 부족이나 건조화, 유기물의 부족 등의 문제점들을 보이고 있다. 특히 비산이 심한 지역의 비탈면은 식생피복율이 현저히 떨어지고 시간이 경과함에 고사율이 증가되어 피복율이 더 저하되고 또다시 침식 및 비산이 증가하는 악순환이 이루어지고 있는 상황이다. 따라서 본 연구에서는 침식이나 비산에 저항하기 위해 친환경 토양안정재를 적용하고, 적정 배합비 결정을 위해 장기침수시험과 유수저항시험을 실시하였다. 친환경토양안정재와 기존의 녹화토기반재를 활용한 장기침수시험결과, 토양안정재의 혼합율 0%는 30시간, 2%는 40일 후 100% 붕괴가 발생되었으며, 4% 이상의 혼합비에서는 실험종료시까지 시료의 원형이 그대로 남아 있어 2% 이상의 토양안정재가 극한 조건에서도 형상을 유지하는데 영향을 줄 수 있는 혼합비임을 확인하였다. 또한, 식생기반재의 구조적 안정성을 평가하기 위해 인공강우시험을 40, 45, $55^{\circ}$ 경사비탈면에 대해 실시하였으며, 토양안정재의 혼합비 0, 4, 8%에 대해 유수저항시험을 실시하고 침식저항능력을 평가하였다. 실험결과, 토양안정재의 혼합에 따라 유실률이 급격히 감소하는 경향을 보이는 등 비산을 방지하거나 우수에 의한 침식에 저항하기 위해 적용한 친환경 토양안정재가 큰 유실감소효과를 거둘 수 있을 것으로 판단된다.

• Journal of the Korean Wood Science and Technology
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• 제42권4호
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• pp.420-427
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• 2014

제재과정에서 발생되는 톱밥과 농업부산물인 왕겨의 활용방안을 찾고자 왕겨의 혼합비율에 따라 혼합보드를 제조하고 수지함침 및 탄화과정을 거쳐 혼합세라믹을 제조하여 왕겨의 혼합비율에 따라 물성을 조사하였다. 같은 수지함침율에서 왕겨혼합비율이 증가함에 따라 탄화 후 밀도 및 휨강도는 증가하였으나 중량감소율은 감소하였다. 또한 같은 탄화온도에서 밀도와 휨강도는 왕겨혼합비율이 40%일 때 가장 큰 것으로 나타났다.

• 한국세라믹학회지
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• 제31권4호
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• pp.375-380
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• 1994

Matrices retaining electrolyte in phosphoric acid fuel cell were prepared with SiC to SiC whisker mixing ratios of 1:0.5, 1:1, 1:1.5, 1:2, 1:3 by tape casting method. When viscosity of the slurry was 5.9 poise and the SiC to SiC whisker mixing ratios were 1:1, 1:1.5, 1:2, the ranges of porosity, acid absorbency and bubble pressure were 80~90%, 2.5~6 and 700~2200 mmH2O, respectively. Those ranges are acceptable for a practical electrolyte-retaining matrix. With increasing the mixing ratio of SiC whisker to SiC, the porosity and the vol.% of large pores in the main pore size distribution which is between 1 and 10 ${\mu}{\textrm}{m}$, increased rapidly. Impedance spectroscopy was measured to know characteristics of matrix inside and contact region of matrix to catalyst layer. When the SiC to SiC whisker mixing ratio was 1:2, hydrogen ions were transported in the matrix most effectively because of high ionic conductivity and low activation energy due to high acid absorbency in spite of high interfacial resistance. The cell current density of the cell made using the matrix was 220 mA/$\textrm{cm}^2$ at 0.7 V.

• Nuclear Engineering and Technology
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• 제45권3호
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• pp.367-376
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• 2013

This study investigated mixing scenarios of the low and high conversion ratios (CRs) of fast reactors (FRs). The fuel cycle was modeled so as to minimize the spent fuel (SF) or transuranics (TRU) inventories. The scenarios were modeled for a single low CR of 0.61 and a high CR of 1.0. The study also investigated the mixing scenario of low-high CR and/or high-low CR. The SF and TRU inventories, associated with different scenarios, were compared to those of the light water reactor (LWR) once-through (OT) case. Also, the important isotope concentration and long-term heat (LTH) load were calculated and compared to those of the OT cycle. As a result, it is known that the deployment of FRs of low CR burns more TRU and results in a reduction of the out-of-pile TRU inventory and LTH with low deployment capacity. This study shows that the mixing strategy of FRs of low and high CR can reduce the SF and TRU inventories with lower deployment capacity as compared with a single deployment of FRs of high CR.

• 대기
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• 제29권2호
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• pp.227-239
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• 2019

This paper reviews various bulk-type cloud microphysics parameterizations (BCMPs). BCMP, predicting the moments of size distribution of hydrometeors, parameterizes the grid-resolved cloud and precipitation processes in atmospheric models. The generalized gamma distribution is mainly applied to represent the hydrometeors size distribution in BCMPs. BCMP can be divided in three different methods such as single-moment, double-moment, and triple-moment approaches depending on the number of prognostic variables. Single-moment approach only predicts the hydrometeors mixing ratio. Double-moment approach predicts not only the hydrometeors mixing ratio but also the hydrometeors number concentration. Triple-moment approach predicts the dispersion parameter of hydrometeors size distribution through the prognostic reflectivity, together with the number concentrations and mixing ratios of hydrometeors. Triple-moment approach is the most time expensive method because it has the most number of prognostic variables. However, this approach can allow more flexibility in representing hydrometeors size distribution relative to single-moment and double-moment approaches. At the early stage of the development of BMCPs, warm rain processes were only included. Ice-phase categories such as cloud ice, snow, graupel, and hail were included in BCMPs with prescribed properties for densities and sedimentation velocities of ice-phase hydrometeors since 1980s. Recently, to avoid fixed properties for ice-phase hydrometeors and ad-hoc category conversion, the new approach was proposed in which rimed ice and deposition ice mixing ratios are predicted with total ice number concentration and volume.

• 유기물자원화
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• 제11권3호
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• pp.60-66
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• 2003

본 연구는 혐기성 소화를 이용한 음식물쓰레기와 하수슬러지 병합처리를 위한 음식물쓰레기 전처리 공정 방안을 모색하기 위하여 수행되었다. 음식물쓰레기 전처리 공정에 따른 음식물쓰레기 단위 공정별 성상 변화와 산발효조 적정 투여 기초조사 및 음식물쓰레기와 하수슬러지 혼합비 특성변화를 통한 산발효조의 효율 향상방안을 검토하였다. 연구결과, 음식물쓰레기의 구성성분은 대부분이 곡류와 채소류로 산발효 공정에서 유기산으로 전환될 가능성이 충분한 것으로 판단되며, 산발효조 투입시 TS의 적정한 범위를 위한 음식물쓰레기와 희석수의 비율은 1:5가 적합한 것으로 나타났다. 음식물쓰레기 분쇄 후 입도 분포 특성을 고려할 때 약 8mm 이하의 입자가 적합하며, 음식물쓰레기와 하수슬러지 슬러지의 혼합비는 3:7 이하가 적합한 것으로 나타났다.

• 한국환경보건학회지
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• 제35권3호
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• pp.226-234
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• 2009

The main objective of this study was to evaluate the effects on shape and size, compressive strength, water absorption and heavy metals leaching with various weight mixing ratios in waste ash brick products using waste recycling MSWI(Municipal Solid Waste Incinerator) bottom ash, steel slag and waste building material. The manufacturing processes for the waste ash brick consist of screening, mixing, conveyor transmission, compaction.forming, and curing steps of raw materials. The weight mixing ratios of steel slag around bottom ash were adjusted within the ranges of 10% to 30%. The reported results show that the width and thickness of the manufactured waste ash brick could be satisfied with $90{\pm}2mm\;and\;57{\pm}2mm$, respectively which are K.S. standards of products qualities. And in case of length, only 20-Ba50Ss30, 20-Ba60Wb20 and 20-Ba50Wb30 for the mixing ratios could be satisfied with $190{\pm}2mm$ that is K.S. standards of products quality. The compressive strength and water absorption for 20-Ba50Ss30 and 20-Ba70Wb10 were over $8N/mm^2$ and below 15% respectively that are K.S. standards of manufactured waste ash brick. The results of tests for the heavy metals leaching in the all manufactured waste ash bricks are also passed to the wastes management regulations. The cost analysis of 20-Ba50Ss30 is evaluated. The manufacturing cost is evaluated 34.3 won/brick with 8 hours and 20tons of raw material per day. Incinerators with problems in bottom ash disposal can therefore derive significant benefits from the application of waste ash brick production.

• 유기물자원화
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• 제17권1호
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• pp.27-38
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• 2009

본 연구는 유기성폐기물인 음식물폐기물과 하수슬러지를 가연성폐기물을 혼재하여 연료로 사용하기 위해서 제조과정과 연소공정에서 발생되는 특성을 분석하였다. 연료화 재질의 특성은 연도분석기를 이용하여 배연가스 성분을 조사하였고, 발열량은 봄베식 열량계를 이용하여 분석하였다. 연료화 재료의 특성연구를 위하여 기초조사 수분함량(%), 가연성 폐기물 비율, 회분량, 중금속, 각 성분 원소분석, 발열량, 중량 혼재비율에 따라서 분석하였다. $RDF_{k-1}$의 연료는 건조하수슬러지, 음식물폐기물 및 가연성폐기물 혼재비율에 따라 제조하였고, $RDF_{k-2}$는 피트모스, 타르 및 하수슬러지 혼합비율에 의해서 제조하였다. 연소실험은 공기비 2와 연소온도 $850^{\circ}C$의 최적조건 상태에서 실험을 실행하였다. 연소실험장치에서 연소시간 5, 10, 15분의 간격으로 실험하였다. 연소장치로의 주입 연료량은 50g을 주입하여 실행하였다. $RDF_{k-1}$의 연료는 혼재비율에 따라서 발열량 실험결과 6,900에서 8,120 kcal/kg까지 분석되었고, $RDF_{k-2}$는 4,014에서 8,050 kcal/kg까지 나타났다. 연도실험에서 연소의 효율은 RDF의 발열량, 수분, 원소구성성분과 재질의 다양한 혼재비율에 큰 영향을 미치는 것으로 나타났다. 제조된 연료의 $RDF_{k-1}$ 연소실험에서 가연성 성분의 혼재비율이 높은 경우 발열량과 $C_xH_y$ 농도 및 회분량이 증가하였다. $RDF_{k-2}$ 경우는 tar의 혼재비율의 증가함에 따라 발열량은 증가하나 회분량, CO와 $C_xH_y$의 농도발생이 증가하는 것으로 나타났다.

• Journal of Welding and Joining
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• 제20권2호
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• pp.65-70
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• 2002

This study was to evaluate GMA welding characteristics of the A15083-O aluminum alloy according to the shield gas mixing ratio and heat input change. The GMA welding of the base metal was carried out with flour different shield gas mixing ratios(Ar100%+He0%, Ar67%+He33%, Ar50%+He50%, and Ar33%+He67%). Regarding the if1uence on the bead shape of the shield gas mixing ratio and heat input, the bead width was greatest in Ar100%+He0% mixture. But the penetration depth and area were greatest in Ar33%+He67% mixture considering that the lower Ax gas ratio, the higher bead depth and area. Also, dilution was also best in the shield gas mixing ratio. The size and number of deflects were least in Ar33%+He67% mixture. Higher He gas ratio resulted in less deflects detected by the radiographic inspection.

• Advances in concrete construction
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• 제9권6호
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• pp.547-556
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• 2020

This study aimed to develop reference materials (RMs) that are chemically stable and can simulate the flow characteristics of cement paste. To this end, the candidate components of RMs were selected considering the currently required properties of RMs. Limestone, slag, silica, and kaolin were selected as substitutes for cement, while glycerol and corn syrup were selected as matrix fluids. Moreover, distilled water was used for mixing. To select the combinations of materials that meet all the required properties of RMs, flow characteristics were first analyzed. The results revealed that silica and kaolin exhibited bilateral nonlinearity. When an analysis was conducted over time, slag exhibited chemical reactions, including strength development. Moreover, fungi were observed in all mixtures with corn syrup. On the other hand, the combination of limestone, glycerol, and water exhibited a performance that met all the required properties of RMs. Thus, limestone, glycerol, and water were selected as the components of the RMs. When the influence of each component of the RMs on flow characteristics was analyzed, it was found that limestone affects the yield value, while the ratio of water and glycerol affects the plastic viscosity. Based on this, it was possible to select the mixing ratios for the RMs that can simulate the flow characteristics of cement paste under each mixing ratio. This relationship was established as an equation, which was verified under various mixing ratios. Finally, when the flow characteristics were analyzed under various temperature conditions, cement paste and the RMs exhibited similar tendencies in terms of flow characteristics. This indicated that the combinations of the selected materials could be used as RMs that can simulate the flow characteristics of cement paste with constant quality under various mixing ratio conditions and construction environment conditions.