• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.139-140
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• 2020

LEFC, a emotional concrete and one of light-transmitting concrete, has a characteristic of transmitting light, so its utility is great. In this study, in order to utilize LEFC under ultraviolet conditions, GST, a low-cost high-performance photocatalyst, was incorporated into the UHPC mix proportion. Specimens were prepared by applying ISO 22197-1. The test was conducted according to the standard and it was confirmed that the NO removal performance was over 50%.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.30-31
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• 2021

This study aims to build a deep learning model that can predict the value of concrete mixing properties according to a given concrete strength value. A model was created for a total of 1,291 concrete data, including 8 characteristics related to concrete mixing elements and environment, and the compressive strength of concrete. As the deep learning model, DNN-3L-256N, which showed the best performance on the prior study, was used. The average value for each characteristic of the data set was used as the initial input value. In results, in the case of 'curing temperature', which had a narrow range of values in the existing data set, showed the lowest error rate with less than 1% error based on MAE. The highest error rate with an error of 12 to 14% for fly and bfs.

• Structural Engineering and Mechanics
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• 제47권5호
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• pp.701-711
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• 2013

People started to replace natural aggregate with recycled aggregate for a number of years due to disposal problem and certain other potential benefits. Though there are number of drawbacks with use of recycled aggregates like lesser modulus of elasticity, low compressive strength, increase in shrinkage, there are results of earlier studies that use of chemical and mineral admixtures improves the strength and durability of recycled concrete. The use of recycled aggregate from construction and demolition wastes is showing prospective application in construction as alternative to natural aggregates. It conserves lot of natural resources and reduces the space required for the landfill disposal. In the present research work, the effect of recycled aggregate on strength and durability aspects of concrete is studied. Grade of concrete chosen for the present work is M50 (with a characteristic compressive strength of 50 MPa). The recycled aggregates were collected from demolished structure with 20 years of age. Natural Aggregate (NA) was replaced with Recycled Aggregate (RA) in different percentages such as 25, 50 and 100 to understand its effect. The experiments were conducted for different ages of concrete such as 7, 14, 28, 56 days to assess the compressive and tensile strength. Durability characteristics of recycled aggregate concrete were studied with Rapid chloride penetration test (as per ASTMC1202), sorptivity test and acid test to assess resistance against chloride ion penetration, capillary suction and chemical attack respectively. Mix design for 50 MPa gives around 35 MPa after replacing natural aggregate with recycled aggregate in concrete mix and the chloride penetration range also lies in moderate limit. Hence it is understood from the results that replacement of NA with RA is very much possible and will be ecofriendly.

• 보건행정학회지
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• 제20권1호
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• pp.19-36
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• 2010

Fee for long-term care insurance in Korea are determined in proportion to resources utilized according to severity rather than based on categorization of beneficiaries in consideration of the characteristics of resource utilization. This adoption is based on the assumption that as beneficiaries of long-term care insurance, characteristically, demands social services rather than needs medical treatments, the characteristics of beneficiaries and the quality of utilized resources are comparatively homogenous. Therefore, the proposition is that the size of resource consumed by beneficiaries in the same grade is identical. However, even in the same grade, the level of utilized resources is different depending on the characteristic of beneficiaries. In this regard, this study is to examine whether there are differences in the volumes of utilized resources depending on the characteristics of beneficiaries even in the same grade. We analyzed time study data for 2003, 2005, 2006 which conducted by the Korea Institute for Health and Social Affairs. To look at differences in the volumes of utilized resources, we identified characteristics of beneficiaries that influence utilized resource volumes and categorized services provided by facilities into the rehabilitation treatment category, the problematic behavior category, and the physical malfunction category. Then, we examined each service in consideration of service difficulty levels and wage weights. The result of examination showed that differences in utilized resource volumes exist in all three grades depending on the characteristics of beneficiaries. Especially, in the first grade with a high level of seriousness, utilized resource volumes were different for those three service categories and the problematic behaviour category considered dementia was found to consume the largest volume of resources. Moreover, there was the inversion phenomenon of utilized resources volumes between the grades. This result indicates that utilized resource volumes are different even in the same grade depending on the characteristics of beneficiaries and it is required to consider case-mix for reflection of the volumes of utilized resources depending on the characteristics of beneficiaries.

• 한국터널지하공간학회 논문집
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• 제13권6호
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• pp.557-569
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• 2011

강섬유보강 콘크리트는 숏크리트와 쉴드터널 세그먼트 등에 널리 이용되는 건설재료이다. 강섬유와 이형철근이 동시에 보강된 콘크리트 구조물에서 강섬유와 철근의 부식은 장기적 내구성능에 영향을 미칠 수 있다. 그러므로 이러한 구조물의 부식 가능성과 침투성능에 대한 적정한 평가가 가능한 방법의 도출이 필요하다. 따라서 본 연구에서는 강섬유와 철근이 동시에 보강된 콘크리트의 부식평가방안에 대한 실험적 연구를 수행하였다. 강섬유의 혼입량, 이형철근의 부식유무 등을 변수로 실험체를 제작하였으며, 각 변수 등이 표면전기저항치에 미치는 영향을 분석하였다. 실험결과, 강섬유는 전류의 교란을 발생시켜 표면전기저항치를 크게 저하시키는 것으로 확인되었다. 또한 강섬유가 3% 이상 혼입이 되면, 내부 이형 철근의 부식상태 및 부식가능성에 대한 평가가 불가능한 것으로 판단된다.

• 농업과학연구
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• 제25권2호
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• pp.176-180
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• 1998

충남지역 농특산물인 밤 및 호도의 과육을 분말화하여 아이스크림 믹스의 원료로 1~5% 첨가하고 아이스크림을 제조한 후, over run, 제품의 조성분 및 관능검사를 실시한 결과는 다음과 같다. 1. Over run의 측정에 있어서는 밤 분말 첨가의 경우 35.75~38.81%로서 41.18%인 control구에 비하여 낮게 나타나고 호도 첨가구에 있어서는 36.31~40.38%로서 control구에 비하여 낮았다. 2. 제품의 화학적 조성은 밤 분말을 첨가한 아이스크림의 경우 무지고형분과 단백질이 31.05~31.73%, 4.48~4.78%로서 control구에 비하여 높았고 호도 첨가구에 있어서는 지방량이 12.21~21.38%, 단백질량이 4.63~5.27%로서 control구에 비하여 높은 함량을 나타내었다. 3. 관능검사 결과 밤 첨가 아이스크림은 향취와 맛에 있어서 control구에 비하여 우수하였고 호도 첨가구는 향취에 있어서 통계적인 유의성이 인정되는 (0.05%) 우수성을 나타내었다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1997년도 춘계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.34-34
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• 1997

The effect of alloying mode and porosity on the axial tension-tension fatigue behavior of a P/M steel of nominal composition Fe-4w/o Ni-1.5w/o Cu-O.5w/o Mo-O.5w/o C has been evaluated. Alloying modes utilized were elemental powder mixing, partial alloying(distaloy) and prealloying by water atomization; in each case the carbon was introduced as graphite prior to sintering. Powder compacts were sintered($1120{\circ}C$/30 min.) in 7Sv/o $H_2$/25v/o $N_2$ to densities in the range 6.77-7.2 g/$cm^3$. The dependence of fatigue limit response on alloying mode and porosity was interpreted in terms of the constituent phases and the pore and fracture morphologies associated with the three alloying modes. For the same nominal composition, the three alloying modes resulted in different sintered microstructures. In the elemental mix alloy and the distaloy, the major constituent was coarse and fine pearlite, with regions of Ni-rich ferrite, Ni-rich martensite and Ni-rich areas. In contrast, the prealloy consisted primarily of martensite by with some Ni-rich areas. From an examination of the fracture surfaces following fatigue testing it was concluded that essentially all of the fracture surfaces exhibited dimpled rupture, characteristic of tensile overload. Thus, the extent of growth of any fatigue cracks prior to overload was small. The stress amplitude for the three alloying modes at 2x$l0^6$ was used for the comparison of fatigue strengths. For load cycles <3x$l0^5$, the prealloy exhibited optimum fatigue response followed by the distaloy and elemental mix alloy, respectively. At load cycles >2x$l0^6$, similar fatigue limits were exhibited by the three alloys. It was concluded that fatigue cracks propagate primarily through pores, rather than through the constituent phases of the microstructure. A decrease in pore SIze improved the S-N behavior of the sintered steel.

• 한국초지조사료학회지
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• 제41권4호
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• pp.259-266
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• 2021

The present study was aimed to estimate the effect of ensiling period and bacterial inoculants on chemical compositions and fermentation characteristics on rye silage harvested at delayed stage. Rye (Secale cereale L.) was harvested after 20 days of heading stage (29.4% dry matter, DM). The harvested rye forage was applied with different inoculants following: applications of distilled water (CON), Lactobacillus brevis (LBB), Leuconostoc holzapfelii (LCH), or mixture of LBB and LCH at 1:1 ratio (MIX). Each forage was ensiled into 20 L mini bucket silo (5 kg) for 50 (E50D) and 100 (E100D) days in triplicates. The E50D silages had higher in vitro digestibilities of DM (IVDMD, p<0.001) and neutral detergent fiber (IVNDFD, p=0.013), and lactate (p=0.009), and acetate (p=0.011) than those of E100D, but lower pH, lactic acid bacteria (LAB), and yeast. By inoculant application, LCH had highest IVDMD and IVNDFD (p<0.05), while MIX had highest lactate and lowest pH (p<0.05). The CON and LCH in E50D had highest LAB and yeast (p<0.05), whereas LBB in E100D had lowest (p<0.05). Therefore, this study concluded that LCH application improved the nutrient digesbility (IVDMD and IVNDFD) of lignified rye silage, and longer ensiling period for 100 days enhanced the fermentation characteristics of silage compared to ensiling for 50 days.

• 대한토목학회논문집
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• 제26권4A호
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• pp.775-785
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• 2006

본 논문은 우수한 부착성능과 더불어 단순한 공정으로 생산이 가능한 GFRP 보강근의 표면성형 기법을 제시하였다. 논문에는 제안하고자하는 표면성형기법에 대한 내용과 개발된 보강근의 콘크리트 부착성능에 대하여 언급하였다. 본 논문에서 제안하는 표면성형공법은 에폭시레진에 초단섬유인 milled glass fibers를 혼입하여 GFRP 보강근의 외부에 프레스 성형하는 공법이다. milled fibers의 적적한 혼합비를 결정하기 위하여 다양한 혼입비로 제작된 경화된 에폭시 시편의 압축강도실험과 다양한 혼입비의 표면형상을 갖는 부착시험편의 pull-out 실험이 수행되었다. 실험결과, 정적하중하에서 뿐 아니라 환경하중 재하상태에서도 milled fibers의 혼입량이 증가할수록 콘크리트와의 부착성능이 증진됨을 확인됨으로써 본 공법의 효용성을 검증하였다.

• Journal of Animal Science and Technology
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• 제47권6호
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• pp.975-984
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• 2005

본 연구는 유기태 셀레늄 급여가 한우의 생산성에 미치는 영향을 연구하기 위하여 유기태 셀레늄 혼합제의 첨가량을 달리하여 비육말기 거세한우에 급여하였을 때 나타나는 성장, 육질, 체내 셀레늄 분포 및 경제성을 분석 평가하고자 실시하였다. 총 45두의 비육후기 거세한우를 유기태 셀레늄 혼합제 급여 수준에 따라 15 두씩 3개의 시험구에 임의배치 하고 사료 건물 중 셀레늄 함량을 0.5ppm 수준이 되도록 유기셀레늄 혼합제를 급여한 시험구(0.5ppm OSM구), 1.0ppm 수준으로 처리한 시험구(1.0ppm OSM구) 및 대조구(혼합제 무첨가 관행사육구)로 나누어 4개월간 사양시험을 수행한 결과는 다음과 같다. 3개의 시험구간 총 증체량, 일일 증체량 및 사료 섭취량의 통계적 유의성은 없었다(p>0.05). 도체중량, 배최장근면적, 등지방두께, 육량지수, 육색지수, 지방색, 연도, 성숙도 등에서도 시험구간 유의적 차이가 인정되지 않았다(p>0.05). 그러나 상대적으로 유기태 셀레늄과 함께 미생물 제제가 많이 공급된 1.0ppm OSM 구에서 사료효율(사료요구량과 증체당 TDN), 도체등급 및 육질등급이 다른 시험구보다 좋은 성적을 나타냈다. 각 조직의 셀레늄은 유기태 셀레늄 급여에 의해 함량이 증가되었는데 0.5ppm OSM 구에서는 간과 우둔 그리고 1.0ppm OSM 구에서는 신장, 간, 등심 및 우둔의 셀레늄함량이 대조구보다 높았다(p<0.05). 조직 내 셀레늄 함량은 전반적으로 1.0ppm OSM 구에서 가장 높게 나타났으며, 각 조직간 셀레늄 함량은 신장, 간, 등심 그리고 우둔 순으로 높았다. 사양시험 종료시 도체 경락가를 기초로 경제성을 평가하였을 때 1.0ppm OSM 구가 대조구에 비하여 수익성이 5.5% 정도 높았다. 결론적으로, 유기셀레늄 혼합제의 급여와 급여수준은 사료섭취량, 증체량 그리고 도체특성에 큰 영향을 주지 않았지만 각 조직의 셀레늄 함량을 증가시켰다. 또한 유기셀레늄 혼합제를 1.0ppm 수준으로 사용하였을 때 육우 판매수입이 증가하였다.