• 한국세라믹학회지
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• 제51권2호
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• pp.115-120
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• 2014

Quicklime(CaO) is generally obtained through the calcination of limestone, the main component of which is calcium carbonate($CaCO_3$). Quicklime generates high-temperature heat when reacting with water, forming slaked lime($Ca(OH)_2$). The industrial sectors for limestone are determined by the hydraulic activity of slaked lime, which is obtained by measuring temperature changes during the hydration reaction. Accordingly, this study examined the different crystallographic characteristics of limestone as affected by the geological origins of the regions where the limestones were produced, and how these characteristics affected hydraulic activity. Six limestone samples were collected from the Jecheon and Cheongsong areas and the hydraulic activities were measured in accordance with KS E 3077. The results indicate that limestone produced in the Cheongsong area, recrystallized through metamorphism caused by hydrothermal alteration, hada larger grain size of calcite than that of the Jecheon area, and displays a tendency of changing to marble. Limestone from the Cheonsong area showed more radical reaction in the early stage of hydration compared to that ofthe Jecheon area. In addition, it was revealed that limestone having more impurities like $SiO_2$ have lower hydraulic activity.

• 한국세라믹학회지
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• 제37권5호
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• pp.453-458
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• 2000

Glasses showing the composition of blast furnace slag were made in the laboratory, and the effect of the chemical composition on the latent hydraulic activity of the slags was examined. The latent hydraulicity was greatly influenced by the composition change, the optimal characteristic of the hydraulicity was achieved at the slag composition of 47CaO:20Al2O3:33SiO2. The content of CaO and Al2O3 were not equivalent to the hydraulic activity of the slags as the b-formula (KS L 5210) indicates. Good latent hydraulicity was shown when Al2O3 was richly contained at the high (CaO＋Al2O3):SiO ratio, while the more the MgO content was, the more negative the result turned out.

• The Korean Journal of Ceramics
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• 제6권4호
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• pp.339-342
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• 2000

In the present study, we attempted to apply DV-X$\alpha$ method to expressing the reactivity of materials. The expression of reactivity was discussed by comparison between ${\gamma}$-C$_2$G having hydraulic activity and ${\gamma}$-C$_2$S not having hydraulic activity at normal conditions. It was found that the model cluster used for calculation can finely reproduce the bulk and surface states using with and without point charge, respectively. The hydration state was also represented by placing OH￣ on the surface of the cluster. It was calculated that the bond strength of the first layer (as surface) was bigger than that of inner layers (as bulk) for ${\gamma}$-C$_2$S while that of the first layer for ${\gamma}$-C$_2$G was smaller than that of inner layers. Subsequently a model in which OH￣ is coordinated on Ca at the surface was also calculated. The bond strength with OH￣ was stronger than that without OH￣, while for ${\gamma}$-C$_2$G the bond strength with OH￣ was weaker than that without OH￣. From these results, it is concluded that the hydraulic activity depends on whether the bond strength for hydrated state becomes weaker than that unhydrated state or not.

• 한국식물생명공학회:학술대회논문집
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• 한국식물생명공학회 2005년도 추계학술대회 및 한일 식물생명공학 심포지엄
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• pp.71-80
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• 2005

Effects of low temperature ($8^{\circ}C$) on the hydraulic conductivity of young roots of a chilling-sensitive (cucumber; Cucumis sativus L.) and a chilling-resistant (figleaf gourd; Cucurbita ficifolia Bouche) crop have been measured at the levels of whole root systems (root hydraulic conductivity, $Lp_r$) and of individual cortical cells (cell hydraulic conductivity, Lp). In figleaf gourd, there was a reduction only in hydrostatic $Lp_r$ but not in osmotic $Lp_r$ suggesting that the activity of water channels was not much affected by low root temperature (LRT)treatment in this species. Changes in cell Lp in response to chilling and recovery were similar asroot level, although they were more intense at the root level. Roots of figleaf gourd recovered better from LRT treatment than those of cucumber. In figleaf gourd, recovery (both at the root and cell level) often resulted in Lp and $Lp_r$ values which were even bigger than the original, i.e. there was an overshoot in hydraulic conductivity. These effects were larger forosmotic (representing the cell-to-cell passage of water) than for hydrostatic $Lp_r$. After a short term (1 d) exposure to $8\;^{\circ}C$ followed by 1 d at $20\;^{\circ}C$, hydrostatic $Lp_r$ of cucumber nearly recovered and that of figleaf gourd still remained higher due to the overshoot. On the contrary, osmotic $Lp_r$ and cell Lp in both species remained high by a factor of 3 as compared to the control, possibly due to an increased activity of water channels. After pre-conditioning of roots at LRT, increased hydraulic conductivitywas completely inhibited by $HgCl_2$ at both the root and cell levels. Different from figleaf gourd, recovery from chilling was not complete in cucumber after longer exposure to LRT. It is concluded that at LRT, both changes in the activity of aquaporins and alterations of root anatomy determine the water uptake in both species. To better understand the aquaporin function in plants under various stress conditions, we examined the transgenic Arabidopsisand tobacco plants that constitutively overexpress ArabidopsisPIP1;4 or PIP2;5 under various abiotic stress conditions. No significant differences in growth rates were found between the transgenic and wild-type plants under favorable growth conditions. By contrast, overexpression of PIP1;4 or PIP2;5 had a negative effect on seed germination and seedling growth under drought stress, whereas it had a positive effect under cold stress and no effect under salt stress. Measurement of water transport by cell pressure probe revealed that these observed phenotypes under different stress conditions were closely correlated with the ability of water transport by each aquaporin in the transgenic plants. Together, our results demonstrate that PIP-type aquaporins play roles in seed germination, seedling growth, and stress response of Arabidopsis and tobacco plants under various stress conditions, and emphasize the importance of a single aquaporin-mediated water transport in these cellular processes.

• 한국농림기상학회지
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• 제11권4호
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• pp.151-161
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• 2009

토양수리특성을 규명하는 것은 사면에서의 수문과정을 이해하는 과정에서 중요한 부분이다. 이 연구에서는 토양공극발달 및 수리학적 특성의 시간적인 변화특성에 대해서 조사하였다. 특히, 대공극 흐름이나 수리전도도와 관련된 특성들을 설마천 유역의 범륜사 사면과 광릉연구유역의 원두부 소사면에서 관측하였다. 연직 흐름의 측정을 위해 사용된 기기는 장력 침투계로 약 8개월동안 토양층 표면의 수리전도도를 측정하였다. 측정된 결과는 3월, 6월, 9월의 수리전도도가 상대적으로 크지만, 5월과 10월의 경우는 낮은 값을 보여준다. 이는 식생의 세근활동 등과 관련된 공극구조의 발달양상과 선행강우사상으로 인한 토양수분의 영향으로 설명될 수 있다. 침투과정에서 있어서 대공극은 산림 유역에서의 수리전도도에 미치는 영향은 대단히 크며, 수문학적 과정에 있어서도 매우 중요한 기작이다. 본 연구는 현장에서 측정된 토양 수리특성의 시간적 불균일성을 보여주는 사례로 사면에서의 침투과정이 동적인 과정임을 보여주고 있고, 관련된 다양한 토양 수리학적 특성들은 국내 산지사면에서 발생되는 수문기작을 이해하는데 중요한 기초 자료가 된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.15-21
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• 2007

Due to a decreasing tendency of river runoff in the Laohahe River basin in North China, quantitative analysis was made with the aid of the conceptual Xinanjiang model under the background of nature climate variability as well as human-induced climate change according to the long-term observational hydrometeorological data. In the past, the human effect on surface water resources was estimated by investigating the impact of human activities on each item in the equation of water balance, so as to calculate water quantity of each item in the original natural status. It seems to be clear conceptually. It is appropriate just for the case of direct impact, such as water transfer from one basin to another, water storage by various scales of hydraulic projects, besides a huge amount of investigation and indeterminate statistics data when applied in practice. It is difficult for us to compute directly water consumption due to the implementation of measures for soil conservation, the improvement of farming techniques in agriculture, the growth of population in towns and villages, and the change of socioeconomic structure. In view of such situation, the Xinanjiang model was used to separate human impact from the climatic impact on water resources. Quantitatively human activity made river runoff decrease by 1.02, 50.67, 58.06 mm in 1960's, 1970's, 1980's, respectively, while by 97.2 mm in 1990's in the sense of annual average in the Laohahe River basin.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.217-218
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• 2011

The advantages of blast-furnace slag concrete may include lower hydration heating velocity, restraint on concrete temperature increase, long-age strength improvement due to latent hydraulic reaction, improved water tightness, and repulsion to chemical erosion. These advantages contribute to the high quality of the blast-furnace slag concrete. However, the blast-furnace slag concrete has its limitations as well. These disadvantages may include retarded setting and elongated retention of mold due to the weak strength of early-age. Nevertheless, much research is currently under way to improve the aforementioned issues. To improve activity of blast furnace slag powder, alkaline irritants has been used. In this study, we analyze effect on activity fineness and rate of substitution of Alkali Activator toward activity.

• Ecology and Resilient Infrastructure
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• 제1권1호
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• pp.8-18
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• 2014

본 연구에서는 수공구조물 하류에서의 하천흐름 특성을 3차원 수치모형인 Delft3D 모형을 이용하여 분석하고, 하천흐름 특성을 분석한 결과를 기반으로 홍수시에 어류의 피난처를 예측하였다. 수공구조물은 통수단면적을 변화시키고 유속과 수심을 변화시켜서 어류활동에 영향을 준다. 대상유역인 구미보 직하류에서는 흐름의 중심이 되는 저수로가 좌안으로 집중되면서 우안에서 수심이 낮고, 유속이 느리게 나타나서 어류의 피난처 형성은 우안을 중심으로 발생하였다. 어류의 활동범위를 분석하기 위해 수직방향 유속을 비교한 결과, 30년 빈도와 50년 빈도 경우 우안에서 최대 0.0043 m/s, 0.0052 m/s로 나타났고, 80년 빈도와 100년 빈도는 좌안에서 최대 0.0046 m/s, 0.0039 m/s로 나타났다. 또한 유량이 증가함에 따라 수심이 깊어지고 난류에너지가 상승하여 어류의 피난처가 감소되었다. 30년 빈도 홍수량와 100년 빈도 홍수량에 대하여 어류의 피난처를 비교하면 우안에 형성되는 어류의 피난처 예상 면적이 61.5%에서 39.0%으로 감소하였다.

• Journal of Construction Engineering and Project Management
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• 제3권2호
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• pp.21-34
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• 2013

Various risk factors affect construction projects. Due to the uncertainties created by risk factors, actual activity durations frequently deviate from the estimated durations in either favorable or adverse direction. For this reason, evaluation of schedule uncertainty is required to make decisions accurately when managing construction projects. In this regard, this paper presents a new computer simulation model - the Repetitive Schedule Risk Analysis Model (RSRAM) - to evaluate unit-based repetitive building project schedules under uncertainty when activity durations and risk factors are correlated. The proposed model utilizes Monte Carlo Simulation and a Critical Path Method based repetitive scheduling procedure. This new procedure concurrently provides the utilization of resources without interruption and the maintenance of network logic through successive units. Furthermore, it enables assigning variable production rates to the activities from one unit to another and any kind of relationship type with or without lag time. Details of the model are described and an example application is presented. The findings show that the model produces realistic results regarding the extent of uncertainty inherent in the schedule.

• 한국화재소방학회논문지
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• 제17권4호
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• pp.92-97
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• 2003

침수 경험이 있는 지역에 있어서 수해에 따른 인명 피해의 발생을 방지하기 위해서는 지역주민의 피난행동양식의 분석과 수방관련정보의 공개 등과 같은 적극적인 재해 대응대책이 중요하다. 피난행동을 규정하는 심리적인 영향요인에 대해서는 주민의 의식조사를 토대로 내$.$외적인 요인으로 분류하여 분석하였다. 또한 수리모형 실험을 통하여 적정 피난수심을 유도하였으며 이와 같은 노력은 금후 침수심을 고려한 피난훈련을 통하여 주민의 수해에 대한 경각심을 고취시킴으로써 효과적인 수방활동에 기여할 것이다.