• 한국농공학회지
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• 제22권3호
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• pp.46-59
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• 1980

This study was conducted to obtain the most effective distribution of grain size and the optimum lime content for lime-soil stabilization. To achieve the aim, the change of consistency, the characteristics of compaction and unconfined compressive strength were tested by adding of 0, 4, 6, 8, 10 and 12 percent lime by weight for all soils adjusted by given ratios of sand to clay. The results obtained were as follows; 1. There was a tendency that the plasticity index of lime-soil mixture was decreased by increasing the amount of lime, whereas the liquid limit was varied irregularly and the plastic limit was increased. 2. With the addition of more lime, the optimum moisture content of lime-soil mixture was increased, and the maximum dry density was decreased. 3. The optimum lime content of lime-soil mixture was varied from soil to soil, and the less amount of small grain size, the less value of optimum lime content. 4. The optimum distribution of grain size for lime-soil mixture was in the soil, having the ratio of about 60 percent of cohesive clay and about 40 percent of sand by weight. 5. In the soil having fine grain size, the effect of curing appeared for long periods of time, whereas the increasing rate of unconfined compressive strength was great on the soil of coarse grain size in the earlier stage of curing period.

• Elastomers and Composites
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• 제49권3호
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• pp.204-209
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• 2014

단일벽 카본나노튜브 (SWCNT)/에폭시 복합체에 sodium-montmorillonite ($Na^+$-MMT)을 첨가하여 MMT크기와 MMT/SWCNT 비율이 복합체의 기계적 전기적 성질에 미치는 영향에 대하여 살펴보았다. 다른 크기를 갖는 3종류의 MMT를 사용하였으며, 모두 SWCNT의 분산에 효과적임을 알 수 있었다. MMT함량이 증가함에 따라 SWCNT/에폭시 복합체의 기계적인 성질은 증가하였으며, 임계함량에 도달한 후에는 감소하기 시작하였다. 그러나 표면전기저항은 MMT 함량이 증가함에 따라 감소하였으며, 임계함량에 도달한 후 증가하기 시작하였다. 최대 기계적 성질과 최소 전기특성은 임계 MMT/SWCNT 비율은 MMT 크기에 크게 의존하였으며, 이는 MMT크기가 증가함에 따라 감소하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권1호
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• pp.74-81
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• 2010

The effects of different levels of natural clay enterosorbent on the growth, nutrient availability, and genital organs of post-weaning female pigs fed with an addition of zearalenone (ZEA) were investigated in the study. A total of thirty-five post-weaning gilts ($L{\times}Y{\times}D$) with an average body weight of 12.36${\pm}$1.46 kg were used in the test. The gilts were raised individually in metabolism cages and fed a corn-soybean meal-whey basal diet with an addition of 0 or 1 mg/kg of ZEA for 24 d with four levels of natural clay enterosorbent added in the feed. The treatments were: i) control; ii) control+2.5 g/kg clay; iii) control+1 mg/kg ZEA; iv) control+1 mg/kg ZEA+1.25 g/kg clay; v) control+1 mg/kg ZEA+2.5 g/kg clay; vi) control+1 mg/kg ZEA+5.0 g/kg clay; vii) control+1 mg/kg ZEA +10 g/kg clay. Pigs fed diets contaminated with additional purified ZEA had significantly reduced apparent digestibility of crude protein (CP), gross energy (GE) and apparent metabolic rate of GE (ME/GE, p<0.05) without changes of net protein utilization (NPU, p>0.05). Final body weight, average daily gain (ADG), average daily feed intake (ADFI), vulva length, vulva width, vulva area, relative weights of genital organ and proliferative changes of the ovary tissues in gilts fed ZEA-contaminated diet were increased (p<0.05) compared to the gilts fed the control diet. Addition of natural clay enterosorbent in the ZEA-contaminated diet showed a positive protection effect on ZEA feeding, and the protection was increased linearly or quadratically as clay content increased. However, in pigs fed a diet with clay alone at 2.5 g/kg level there was no significant impact (p>0.05) on all the parameters as compared to the control. It is suggested that feeding ZEA at about 1.0 mg/kg for 24 days might result in a deleterious effect in pigs, and addition of 5 or 10 g clay enterosorbent per kg diet can effectively neutralize the detrimental effects of the ZEA feeding.

• 한국토양비료학회지
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• 제7권4호
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• pp.197-200
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• 1974

여섯가지 성질이 다른 토양에 PCP 흡착실험(吸着實驗)을 습식진탕법(濕式振湯法)으로 행한 결과(結果)는 다음과 같았다. 1) PCP 흡착(吸着)을 지배(支配)하는 주요인(主要因)은 토양(土壤) pH이다. 2) 유기물함량(有機物含量)이 많을수록 PCP의 흡착량(吸着量)이 증가(增加)된다. 3) PCP 흡착량(吸着量)은 토양내(土壤內) 결정성(結晶性) 점토광물(粘土鑛物)의 종류(種類)와는 관계(關係)가 적었다.

• 한국해양학회지
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• 제13권1호
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• pp.19-28
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• 1978

To estimate the chemical mass balance of several kinds of trace metals in sea water, suspended matter and bottom sediments, sixty samples from the Kum and Mankyung estuaries were analyzed. In both estuaries, the distribution patterns of leachabl suspended trace metals and of bottom sediments were established to be similar. The relationship between the metal concentration and clay content of the sediments was found to be such that the metal concentration increases with an increase in clay content. A linear correlation ws determined between pairs of leachable metals (Fe-Zn, Fe-Mn and Zn-Mn) in the Kum estuary. However, in the Mankyung estuary linear relationship does not exist. Finally, it is suggested that the trace metals are reworking in the Kum estuary and those in the Mankyung estuary are sinking.

• 한국세라믹학회지
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• 제11권2호
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• pp.22-30
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• 1974

This study was carried out to investigate the species of iron compounds in kaolin mineral and the bonding relation between the major kaolin and its subordinate iron compound existing as incidental mineral in common clay by means of chemical composition, X-ray diffraction, thermal differential and thermogravimetrie analysis for the application of clays in the field of ceramic raw material. The domestic clay are produced abounduntly in many places, but San-Cheong kaolin, Chu-An clay, and Yeong-Am clay were selected as samples in this experiment because of their frequent utilization in porcelain industry. Two kinds of samples with low and high iron content are picked up respectively from the place of production and elutriated under two micron size to determine the properties and concentration of iron compound very fine particles or colloidal substance of low crystalline grade. Therefore, hydrothermal treatment in autoclave was conducted considering the existence of low crystalline grade of iron compounds known as an amorphoue state in X-ray diffraction pattern furthermore, de-iron treatment of hydrothermal compound was done in order to identify the related iron compound before and after hydrothermal reaction and iron compound which is one of the samples was synthesized for the determination of their compounds state in more detail. The obtained results in this study are as follows: In San-Cheong kaolin, Chu-An clay and Yeong-Am clay 1) It is proved that species accompanying iron compound is $\alpha$-FeOOH form. 2) Iron compound is composed of very fine particles or colloidal substance. 3) The iron substance encircles the fine parts of clay minerals under 2 micron and acts as cementizing agent.

• Geomechanics and Engineering
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• 제12권3호
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• pp.523-539
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• 2017

Clay soils are typical for their swelling properties upon absorption of water during rains and development of cracks during summer time owing to the profile desorption of water through the inter-connected soil pores by water vapour diffusion leading to evaporation. This type of unstable soil phenomenon by and large poses a serious threat to the strength and stability of structures when rest on such type of soils. Even as lime and cement are extensively used for stabilization of clay soils it has become imperative to find relatively cheaper alternative materials to bring out the desired properties within the clay soil domain. In the present era of catastrophic environmental degradation as a side effect to modernized manufacturing processes, industrialization and urbanization the creative idea would be treating the waste products in a beneficial way for reuse and recycling. Bottom ash and ecosand are construed as a waste product from cement industry. An optimal combination of bottom ash-eco sand can be thought of as a viable alternative to stabilize the clay soils by means of an effective dispersion dynamics associated with the inter connected network of pore spaces. A CATIA model was created and imported to ANSYS Fluent to study the dispersion dynamics. Ion migration from the bottom ash-ecosand pile was facilitated through natural formation of cracks in clay soil subjected to atmospheric conditions. Treated samples collected at different curing days from inner and outer zones at different depths were tested for, plasticity index, Unconfined Compressive Strength (UCS), free swell index, water content, Cation Exchange Capacity (CEC), pH and ion concentration to show the effectiveness of the method in improving the clay soil.

• 한국농공학회지
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• 제39권1호
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• pp.102-111
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• 1997

Experiments both in laboratory and field were performed to compare and analyze the characteristics of alluvial clay. The alluvial clay was sampled in test site in which large-scaled tests for the part of the site are under process to suggest the rational method for alluvial clay and the criterion for ground settlement monitoring system. The followings were observed through the experiments : 1. Natural water content, plastic limit, and liquid limit of alluvial clay composed of highly fine grains were 40~80%, 10~20%, and 30~55%, respectively. The values of these properties were relatively small at the ground surface, while the values showed maximum at G.L.- l0m and gradually decreased below the level. 2. Shear strength of alluvial clay was proportionally increased to the depth. Unconfined and triaxial compressive strengths were 0.2~0.6kgf/$cm^2$ and 0.1~0.3kgf/$cm^2$, respectively. 3. Compression index and secondary compression index showed maximum values at G.L.-l0m and gradually decreased below the level. The value of consolidation coefficient was relatively large at the ground surface, constant with decreasing the depth, and incresed when G.L. was below -20m. 4. Piezocone test appeared that alluvial clay with N value of 2~4 was uniformly distributed with 20~ 30m thickness from the ground surface, sand seam was nonuniformly distributed, and penetration pore pressure was 0.8 ~ 1 times of the hydrostatic pressure. Undrained shear strength and consolidation coefficient were 0.04 ~ 0.76kgf / $cm^2$ and $2.88{\times} 10{^-4}~1.3{\times} 10{^-2} cm^2/s$ respectively.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1444-1450
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• 2019

The fast-neutron shielding behaviour (FNSB) of two clay-materials (Ball clay and Kaolin)of Southwestern Nigeria ($7.49^{\circ}N$, $4.55^{\circ}E$) have been investigated using effective removal cross section, ${\Sigma}_R(cm^{-1})$, mass removal cross section, ${\Sigma}_{R/{\rho}}(cm^2g^{-1})$ and Mean free path, ${\lambda}$ (cm). These parameters decide neutron shielding behaviour of any material. A computer program - WinNC-Toolkit has been used for computation of these parameters. The toolkit evaluates these parameters by using elemental compositions and densities of samples. The proficiency of WinNC-Toolkit code was probe by using MCNPX and GEANT4 to model fast neutron transmission of the samples under narrow beam geometry, intending to represent the actual experimental setup. Direct calculation of effective removal cross section ($cm^{-1}$) of the samples was also carried out. The results from each of the methods for each types of the studied clay-materials (Ball clay and Kaolin) shows similar trend. The trend might be the fingerprint of water content retained in each of the samples being baked at different temperature. The compositions of each sample have been obtained by Particle-Induced X-ray Emission (PIXE) technique (Tandem Pelletron Accelerator: 1.7 MV, Model 5SDH). The FNSB of the selected clay-materials have been compared with standard concrete. The cognizance of various factors such as availability, thermo-chemical stability and water retaining ability by the clay-samples can be analyzed for efficacy of the material for their FNSB.

• Applied Biological Chemistry
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• 제18권3호
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• pp.123-144
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• 1975

답토양(畓土壤)의 특징적(特徵的) 현상(現象)인 철(鐵) 및 망간의 이동집적(移動集積) 양상(樣相)을 그의 형태적(形態的) 특성(特性)과 관련(關聯)하여 추구(追求)하는 동시(同時), 철(鐵)의 집적증(集積層)을 정량적(定量)的)으로 판단(判斷)하는 방법(方法)을 모색(模索)하기 위(爲)하여 우리나라 답토양(畓土壤)의 표토중(表土中)에 함유(含有)하고 있는 활성철(活性鐵) 및 역환원성(易還元性) 망간 함량(含量)을 조사(調査)하였고 주요(主要) 답토양(畓土讓)의 형태(形態) 및 이화학적(理化學的) 특성(特性)과 층위별(層位別) 철(鐵) 및 망간의 관계(關係)를 검토(檢討)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 표토(表土)의 활성철(活性鐵) 및 역환원성(易還元性) 망간 함량(含量)은 토양(土壞) 배수(排水)가 불량(不良)할수록 많으며 동일배수조건(同一排求條件)에 있어서는 모래가 많을수록 적었다. 2. 표토(表土)의 활성철함량(活性鐵含量)은 배수조건(排水條件) 및 토성(土性)과는 관계(關係)없이 점토(粘土) 및 미사(微砂)의 총함량(總含豊)과 고도(高度)의 유의성(有意性) 있는 정(正)의 상관(相關)이 있었다. $$\hat{y}=0.3929+(0.0352{\times}clay%)+(0.0001023{\times}silt%)$$ 그러나 점토함량(粘土含量)과 역환원성(易還元性) 망간함량간(含量間)에는 상관(相關)이 없 었다. 3. 토양통별(土壤統別) 각(各) 층위(層位)의 활성철함량(活性鐵含量)(y)과 전철함량(全鐵含量)(x)간(間)에는 유의성(有意性) 있는 정(正)의 상관(相關)이 있어 다음과 같은 회귀식(回歸式)으로 표시(表示)할 수 있었다. $$y=0.361x-0.480(r=0.651^{**})$$ 그러나 역환원성(易還元性) 망간 함량(含量)은 전(全)망간 함량(含量)이 많아짐에 따라 증가(增加)하는 경향(傾向)은 있을 뿐 유의성(有意性)은 없었다. 4. 철(鐵) 및 망간의 집적(集積)은 어느 답토양(畓土壤)에서나 볼수 있으나 현저(顯著)한 집적(集穫)은 배수(排水)가 약간(若干) 양호(良好)한 식질(植質) 및 식양질토양(植壤質土壤)에 형성(形成)되며 배수(排水)가 불량(不良)한 답토양(畓土壤)에서는 토성(土性)에 관계(關係)없이 표토(表土)에 집적(集積)됨을 볼 수 있다. 5. 철(鐵)의 집적층판단(集積層判斷)은 단면관찰(斷面觀察) 또는 층위간(層位間) 활성철함량(活性鐵含量)만으로는 불충분(不充分)하며 전철(全鐵) 대(對) 활성철(活性鐵)의 비(比) 그리고 점토(粘土) 및 미사함량(微砂含量)으로 측정(推定)한 활성철함량(活性鐵含量)을 기초(基礎)로 하여야 하며 망간의 집적층(集積層)은 전(全)망간 및 역환원성(易還元性) 망간 함량(含量)과 그들의 비(比)로 추정(推定)하여야 할 것이다.