• 한국도로학회논문집
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• 제19권2호
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• pp.137-142
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• 2017

PURPOSES :The objective of this study is to evaluate the performance of asphalt mixtures containing inorganic additive and a high content of reclaimed asphalt pavement (RAP). METHODS : The laboratory tests verified the superior laboratory performance of inorganic additive compared to cement, in cold recycled asphalt mixtures. To investigate the moisture susceptibility of the specimens, tensile strength ratio (TSR) tests were performed. In addition, dynamic modulus test was conducted to evaluate the performance of cold recycled asphalt mixture. RESULTS :It was determined that NaOH solution mixed with $Na_2SiO_3$ in the ratio 75:10 provides optimum performance. Compared to Type B and C counterparts, Type A mixtures consisting of an inorganic additive performed better in the Indirect tensile strength test, tensile strength ratio test, and dynamic modulus test. CONCLUSIONS : The use of inorganic additive enhances the indirect strength and dynamic modulus performance of the asphalt mixture. However, additional experiments are to be conducted to improve the reliability of the result with respect to the effect of inorganic additive.

• Structural Engineering and Mechanics
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• 제62권1호
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• pp.1-9
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• 2017

This paper describes laboratory tests carried out to evaluate the influence of class F fly ash (FA) on fracture toughness of plain concretes, specified at the third model fracture. Composites with the additives of: 0%, 20% and 30% siliceous FA were analysed. Fracture toughness tests were performed on axial torsional machine MTS 809 Axial/Torsional Test System, using the cylindrical specimens with dimensions of 150/300 mm, having an initial circumferential notch made in the half-height of cylinders. The studies examined effect of FA additive on the critical stress intensity factor $K_{IIIc}$. In order to determine the fracture toughness $K_{IIIc}$ a special device was manufactured.The analysis of the results revealed that a 20% FA additive causes increase in $K_{IIIc}$, while a 30% FA additive causes decrease in fracture toughness. Furthermore, it was observed that the results obtained during fracture toughness tests are convergent with the values of the compression strength tests.

• 한국분말재료학회지
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• 제27권4호
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• pp.318-324
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• 2020

In the present work, an explicit finite element analysis technique is introduced to analyze the thermal stress fields present in the additive manufacturing process. To this purpose, a finite element matrix formulation is derived from the equations of motion and continuity. The developed code, NET3D, is then applied to various sample problems including thermal stress development. The application of heat to an inclusion from an external source establishes an initial temperature from which heat flows to the surrounding body in the sample problems. The development of thermal stress due to the mismatch between the thermal strains is analyzed. As mass scaling can be used to shorten the computation time of explicit analysis, a mass scaling of 108 is employed here, which yields almost identical results to the quasi-static results.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1995년도 추계학술대회 논문집
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• pp.357-360
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• 1995

Since the streaming electrification phenomena of transformer were made clear on 1970s, many researches have been continued on the improvement of the transformer. This paper describes the effect of additive (BTA, DBPC) and temperature on the streaming electrification of the various materials. The streaming current in the various materials decreases in proportion to the concentration of BTA, results in the inverse electrification. We believe that these results will contribute to the optimal design of HV large-capacity transformer.

• 한국도로학회논문집
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• 제15권4호
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• pp.11-20
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• 2013

PURPOSES : This study is to develop a method to evaluate the compaction effects of asphalt binders using WMA additives and compare their compaction effects on two types of WMA additives, two types of testing temperatures, and three types of asphalt film thicknesses. METHODS : This study is based on laboratory experiments and rheological analysis of the experimental results. Testing materials are aggregate disks, asphalt, and WMA additives. The main testing method is the stress sweep test by using dynamic shear rheometer (DSR). In addition, the testing parameters obtained from the stress sweep results to evaluate lubrication effects are complex modulus and LVE-Limit. RESULTS : At both the first compaction condition ($110^{\circ}C$, 0.3mm) and second compaction condition ($80^{\circ}C$, 0.2mm) assumed, LEADCAP showed better compaction effects than Sasobit. CONCLUSIONS : The temperature $30^{\circ}C$ lower than general compaction temperatures can provide a better sensitivity for the evaluation of compaction effects. If a testing temperature and film thickness are grouped for the proper compaction conditions in the testing results, the compaction performance of each WMA additive can be more clearly discriminated in the grouped testing results matched with the grouped conditions.

• Asian-Australasian Journal of Animal Sciences
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• 제30권1호
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• pp.8-19
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• 2017

Objective: A whole genome association study was conducted to identify single nucleotide polymorphisms (SNPs) with additive and dominant effects for growth and carcass traits in Korean native cattle, Hanwoo. Methods: The data set comprised 61 sires and their 486 Hanwoo steers that were born between spring of 2005 and fall of 2007. The steers were genotyped with the 35,968 SNPs that were embedded in the Illumina bovine SNP 50K beadchip and six growth and carcass quality traits were measured for the steers. A series of lack-of-fit tests between the models was applied to classify gene expression pattern as additive or dominant. Results: A total of 18 (0), 15 (3), 12 (8), 15 (18), 11 (7), and 21 (1) SNPs were detected at the 5% chromosome (genome) - wise level for weaning weight (WWT), yearling weight (YWT), carcass weight (CWT), backfat thickness (BFT), longissimus dorsi muscle area (LMA) and marbling score, respectively. Among the significant 129 SNPs, 56 SNPs had additive effects, 20 SNPs dominance effects, and 53 SNPs both additive and dominance effects, suggesting that dominance inheritance mode be considered in genetic improvement for growth and carcass quality in Hanwoo. The significant SNPs were located at 33 quantitative trait locus (QTL) regions on 18 Bos Taurus chromosomes (i.e. BTA 3, 4, 5, 6, 7, 9, 11, 12, 13, 14, 16, 17, 18, 20, 23, 26, 28, and 29) were detected. There is strong evidence that BTA14 is the key chromosome affecting CWT. Also, BTA20 is the key chromosome for almost all traits measured (WWT, YWT, LMA). Conclusion: The application of various additive and dominance SNP models enabled better characterization of SNP inheritance mode for growth and carcass quality traits in Hanwoo, and many of the detected SNPs or QTL had dominance effects, suggesting that dominance be considered for the whole-genome SNPs data and implementation of successive molecular breeding schemes in Hanwoo.

• Journal of Animal Science and Technology
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• 제52권6호
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• pp.467-473
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• 2010

A total of 4,323,781 records for informal 16 primary linear descriptive traits of dairy cows in Holstein breed from 1988 to 2007 in USA were analyzed to estimate adjustment factors for lactation number and stage. While all factors in the model were highly significant (P < 0.01), major influences on linear type traits were due to lactation number and stage. The frequencies of lactation number 1 through 6 were 58.6, 22.0, 11.8, 4.8, 2.1, and 0.8%, respectively. Further, the frequencies of lactation stage were 0.7, 76.9, 15.3, 4.9, and 2.1%, respectively, for springing, early, medium, late, and dry. To adjust 16 linear traits (stature, dairy form, strength, body depth, rump width, rump angle, legs rear view, leg set, foot angle, fore udder, rear udder height, rear udder width, udder support, udder depth, and front teat placement), additive and multiplicative adjustment factors of lactation number (lactations 2 to 4) and stage (springing, medium, late and dry) were estimated with the solutions in the generalized linear model, assigning lactation 1 and stage early as base class. Additive adjustment factors of lactation number ranged from -1.23 to 2.908, while multiplicative factors ranged from 0.853 to 2.207. Further, additive and multiplicative adjustment factors for lactation stage ranged from -0.668 to 0.785, and from 0.891 to 1.154. Application of adjustment factors to 20 randomly sampled sub-data sets produced the results that additive adjustment factors for both lactation number and stage reduced more mean square of lactation number and stage over 16 linear traits than any combination of adjustments, and leaded additive adjustment factors for both lactation number and stage as a choice of methods for adjustment of informal 16 primary linear type traits collected by classifiers of AI studs.

• 대한토목학회논문집
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• 제26권4A호
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• pp.787-794
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• 2006

고성능 콘크리트는 물-결합재비를 작게 하고, 단위결합재량을 다량으로 사용하므로 콘크리트의 수화열 및 자기수축이 증대되는 경향이 있다. 본 연구에서는 고성능 콘크리트의 수축저감 기술을 구축하는 연구의 일환으로 팽창재와 수축저감제 사용이 고성능 콘크리트의 수축특성에 미치는 영향을 검토하였다. 그 결과, 팽창쟁와 수축저감제는 고성능 콘크리트의 수축을 저감시키는 데 효과가 뛰어나며, 특히 팽창재와 수축저감제를 조합하여 사용할 경우, 각각 단독으로 사용하는 경우보다는 수축 저감 효과가 큰 것으로 확인되었다. 또한 시공성, 강도 및 수축특성을 종합적으로 고려하여 팽창재 5.0%와 수축저감제 1.0%의 조합이 적정배합으로 분석되었다.

• 콘크리트학회논문집
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• 제16권5호
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• pp.605-612
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• 2004

본 연구에서는 W/B $30\%$의 고성능 콘크리트에서 팽창재와 수축저감제 병용 사용에 따른 콘크리트의 기초적 특성 및 수축특성에 대하여 분석하였다. 실험결과, 고성능 콘크리트의 유동성은 팽창재와 수축저감제를 단독사용보다 병용사용일 때 더 크게 저하하여 고성능 감수제의 사용량이 증가되었고, 공기량은 증가하여 AE제의 사용량이 감소되었다. 또한, 압축강도는 팽창재량의 혼입률 $5.0\%$를 사용한 경우가 최대가 되고, 수축저감제는 사용량 증가에 따라 저하되는 것으로 나타났다. 고성능콘크리트의 건조수축 및 자기수축을 저감시키기 위해서는 팽창재와 수축저감제를 혼합하여 사용할 때 가장 양호한 결과가 나타났다. 따라서 유동성, 강도 및 수축특성을 종합적으로 고려한 결과, 본 연구실험 조건에서는 팽창재 $5.0\%$, 수축저감제 $1.0\%$의 조합이 최적배합으로 분석되었다.

• 콘크리트학회논문집
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• 제28권5호
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• pp.519-525
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• 2016

본 논문에서는 혼화제에 따른 3성분계 그라우트에 대하여 자유수축 및 구속수축에 대하여 평가하였다. 본 연구에서 3성분계 그라우트는 플라이애쉬, 지르코늄 실리카퓸을 사용하였고, 팽창재(a, b)와 수축저감제 혼화제를 병용 사용하였다. 또한 유럽규정 EN 445에 따라 그라우트의 기본재료특성 실험을 수행하여 블리딩, 체적변화량, 유동성, 압축강도 실험을 수행하여 기본재료특성 거동도 분석하였다. 실험결과, 팽창재와 수축저감제 혼입률에 따라 유동성은 다소 영향은 없었으나, 우수한 블리딩 및 침하 저감성능과 압축강도를 나타났다. 자유수축 거동에서는 팽창재와 수축저감제를 혼입한 변수들은 0.0E-0.0R 변수보다 최소 29%의 수축저감성능을 보여 주었다. 특히 팽창재 a와 수축저감제를 병용 사용한 변수에서는 수축 저감의 효과가 더욱 우수한 것으로 나타났으며, 혼화제의 혼입률이 증가할수록 텐던 구속에 의한 수축균열은 뒤늦게 발생함을 알 수 있었다. 그러나 유독 팽창재 a 2.0%, 수축저감제 0.50%를 혼입한 변수에서는 우수한 수축저감성능으로 수축균열이 발생하지 않았다. 종합하여 볼 때, 본 연구의 실험 조건에서는 팽창재 a 2.0%, 수축저감제 0.50%인 조합이 PSC 교량용 고품질 3성분계 그라우트의 최적의 혼입률인 것으로 분석된다.