• 한국식품과학회지
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• 제35권3호
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• pp.447-454
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• 2003

동해안 특산 어종인 까나리어간장을 속성제조하기 위하여 여러 가지 발효촉진제를 첨가하여 제조한 제품의 숙성 중 화학성분 및 생균수 변화를 요약하면 다음과 같다. 총 creatine 량은 오징어내장첨가구는 숙성 2개월째, 나머지 첨가구에서는 3개월째까지 증가하였다가 점차적으로 감소하였다. TBA가는 숙성초기에 급격하게 증가한 다음 일정수준 유지 내지 서서히 감소하였으며, 전 숙성기간에 걸쳐 오징어내장첨가구에서 가장 높았으며 다른 첨가구들 간에는 뚜렷한 차이가 없었다. 유리아미노산 함량은 모든 시료에 있어 glutamic acid, alanine, valine, leucine, 및 lysine 등의 함량이 높았고 숙성기간이 길어질수록 증가하였다. 생균수는 모든 실험구에서 숙성 중 증가하였다가 숙성 후기에 감소하였으며 오징어내장 첨가구가 가장 높은 값을 나타내었다. koji 첨가구가 향기 및 맛에 있어서 가장 우수하였고 그 다음이 오징어내장첨가구이었다. 속성 까나리 어간장을 제조하기 위한 속성 발효제로서 오징어내장 및 koji는 발효기간을 단축시킬 수 있을 뿐 아니라 독특한 맛을 형성하므로 까나리 어간장의 속성제조에 발효촉진제로 사용이 가능하다고 보여 진다.

• 콘크리트학회지
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• 제9권2호
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• pp.4-12
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• 1997

• Advances in concrete construction
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• 제7권2호
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• pp.87-96
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• 2019

Self-compacting concretes (SCC) are highly fluid concrete which can flow without any vibration. Their composition requires a large quantity of fines to limit the risk of bleeding and segregation. The use of crushed sand rich in limestone fines could be an adequate solution for both economic and environmental reasons. This paper investigates the influence of quarry limestone fines from manufactured crushed sand on rheological, mechanical and durability properties of SCC. For this purpose, five mixtures of SCC with different limestone fines content as substitution of crushed sand (0, 5, 10, 15 and 20%) were prepared at constant water-to-cement ratio of 0.40 and $490kg/m^3$ of cement content. Fresh SCC mixtures were tested by slump flow test, V-funnel flow time test, L-box height ratio, segregation resistance and rheological test using a rheometer. Compressive and flexural strengths of SCC mixtures were evaluated at 28 days. Regarding durability properties, total porosity, capillary water absorption and chloride-ion migration were studied at 180 days. For the two test modes in fresh state, the results indicated compatibility between slump flow/yield stress (${\tau}_0$) and V-funnel flow time/plastic viscosity (${\mu}$). Increasing the substitution level of limestone fines in SCC mixtures, contributes to the decrease of the slump flow and the yield stress. All SCC mixtures investigated achieved adequate filling, adequate passing ability and exhibit no segregation. Moreover, the inclusion of limestone fines as crushed sand substitution reduces the capillary water absorption, chloride-ion migration and consequently enhances the durability performance.

• 한국안전학회지
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• 제16권1호
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• pp.65-72
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• 2001

Portland cement concrete is made with coarse aggregate, fine aggregate, portland cement, water and, in some cases, selected chemical admixture such as air-entraining agents, water reducer, superplasticizer, and so on, and mineral admixture such as fly ash, silica fume, slags, etc. Typically, in the concrete, the coarse aggregate and fine aggregate will occupy approximately 80 percent of the total volume of the finished mixture. Therefore, the coarse and fine aggregates affect to the properties of the portland cement concrete. As the deposits of natural sands have slowly been depleted, it has become necessary and economical to produce crushed sand(manufactured fine aggregate). It is reported that crushed sand differs from natural sands in gradation, particle shape and texture, and that the content of micro fines in the crushed sand affect to the quality of the portland cement concrete. Therefore, the purpose of this paper is to investigate the characteristics of fresh and hardened concrete with higher micro fines. This study provides a firm data to apply crushed sand with higher micro fines.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.9-14
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• 1998

In this paper, we described the basic elements(flowabiligy, fillingability, elapsed time, pumpability, no-vibrating effects, and etc.) required for the application and quality control of the super flowing concrete(SFC) in Top Down site. Also, manufactured sand and fly ash were used for investigating characteristics of SFC through various experiments(mix design, optimum mix condition) before placing the concrete in site. As a result of this project, the developed SFC shown high flowability and self-fillingability in the joint good enough for the requirement. Futhermore, inner uniformity of the no-vibrated concrete was verified by testing reformed space. Therefore, quality control and compressive strength(360kg/$\textrm{cm}^2$) can be secured by using SFC even without vibrating.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.201-202
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• 2010

본 연구는 육상모래를 사용한 70, 100MPa급 고강도 콘크리트를 현장 배처플랜트를 이용하여 제조하고 강도발현 상태를 파악하고 이들의 내구특성을 검토하기 위하여 제조된 콘크리트에 대해 동결 융해, 탄산화, 염해저항성 실험을 실시하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.271-276
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• 1998

To apply the wear resistant steel plate for heavy duty vehicle, the wear characterisms of various kinds of commercial steel plates were invesigated by dry sand/rubber wheel tester which was tested under scratch abrasion mode. The wear tested pnaterials were boron steels which were manufactured by thereto machanical control process (TMCP) in order to achieve higher hardness. As the result of the test, wear resistance of steel plate increases with the hardness and carbon content. The wear loss of wear resistance steel plate (Hv440) is a half times than tinat of SWS490A (Hv160) steel plate in dry sand-rubber wheel test and the result in field test is similar to this dry sand/rubber wheel test result. Therefore, dry sand/rubber wheel tester can be used to predict the scratch abrasion life of the parts for heavy duty vehicle.

• Design & Manufacturing
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• 제14권4호
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• pp.52-57
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• 2020

In this study attempted to prevent defects due to blow holes among defects of sand casting products. It was intended to reduce the defect rate by reducing the blow hole of the inner surface. Currently, expectations and requirements for the quality level of non-ferrous aluminum casting in the casting industry are increasing. In addition, the shape is complex and the shrinkage precision is required. Among them, the test prototype is expensive to manufacture the mold, and the production time is also long, and the product is manufactured by sand casting. At this time, the highest defect rates are defects caused by shrinkage defects, surface defects, and blow holes.. At this study, the manufacturing time was shortened by using the shape of the fluid movement path in advance. Also, it is possible to reduce defects due to blow holes.

• Advances in concrete construction
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• 제6권5호
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• pp.545-560
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• 2018

The ever-increasing cost of natural sand and the environmental impacts of extracting manufactured sand (quarry sand) calls for exploring the potential to use alternative materials as fine aggregates in concrete. Copper slag and ferrous slag are industrial by products obtained from the smelting process of copper and iron respectively. A large quantity of copper slag and ferrous slag end up being disposed as waste in landfills and this poses a serious threat to the environment. Copper slag and ferrous slag have similar physical and chemical properties as natural sand and also exhibit pozzolanic activity. This paper studies the technical feasibility of industrial by-products such as copper slag and ferrous slag to replace the fine aggregate in concrete by evaluating the workability, strength and durability characteristics of concrete. The test results indicate that the strength properties are not affected by 40% or 100% replacement of quarry sand with iron slag or copper slag. However, 40% replacement of quarry sand with iron slag or copper slag in concrete is recommended considering the durability aspects of concrete.

• 한국산업융합학회 논문집
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• 제25권5호
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• pp.889-898
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• 2022

In this study, sand casting process was applied to manufacture a large aluminum turbo-type fan used for tank powerpack. To apply the sand casting method, the turbo fan was reverse engineered, and after designing three gating systems, the optimal gating system design was selected by performing casting simulation. In the case of the bottom up-gating system, there is a significant temperature loss of the molten alloy during blade filling. When the molten alloy is completely filled into the sand mold, the blade upper tip and front shroud are below the liquidus temperature. In the case of the top down-gating system, molten alloy scattering occurs, but the temperature loss while the blade is filled is smaller than that of the bottom up type. And after the inflow of molten alloy into the mold is completed, the blade upper tip and front shroud are higher than the liquidus temperature. A sand mold was manufactured with the top down-gating system and the casting process was performed. The fan was made perfectly in appearance without any unfilled parts.