• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.696-703
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• 2005

The definition of cake is not established for cake filtration, and especially the definition was impossible for the filtration of the floc already sedimented. The definition is proposed with the experimental method named 'filtration-permeation'. The limit of water content which can be achieved with cake filtration of floc was established with the definition of cake. The expression operation of which the purpose is to reduce the water content of pre-formed filter cake is calculated with our 'unified theory on solid-liquid separation' and compared with the experimental results. The importance of expression is analyzed by the calculated whole procedure of cake filtration and expression. The method determining the most effective operational conditions of filter press including the cake discharge and washing time is proposed.

• Advances in concrete construction
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• v.12 no.6
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• pp.507-515
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• 2021

To evaluate the influence of slag on the alkalinity of pore solution and microstructure of concrete, this paper performs a leaching experiment on hardened cement-slag pastes (HCSP) slice specimens with different slag content in purified water. The pH value of pore solution, average porosity, morphology, phase composition and Ca/Si of HCSP specimens in the leaching process are measured by solid-liquid extraction, saturated-dried weighing, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) and X-ray diffraction (XRD). Results shows that the addition of slag can mitigate an increase in porosity and a decrease in Ca/Si of HCSP in the leaching process. Besides, an appropriate slag content can improve the microstructure so as to obtain the optimum leaching resistance of HCSP, which can guarantee the suitable alkalinity of pore solution to prevent a premature corrosion of reinforced bar. The optimum slag content is 40% in HCSP with a water-binder ratio of 0.45, and an excessive slag causes a significant decrease in the alkalinity of pore solution, resulting in a loss of protection on reinforced bar in HCSP.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1130-1136
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• 2011

This study was carried out to determine the effects of pig slurry on growth of potato (Solanum tuberosum L. cv. Dejima), soil chemistry properties and infiltration water quality in volcanic ash soil and non-volcanic ash soil of Jeju. Fertilization of liquid pig manure was based on nitrogen. In volcanic ash soil and non-volcanic ash soil, there was no difference in the height and diameter of stems in chemical fertilizer and liquid pig manure application treatments. Also yields of potatoes were no significantly difference in chemical fertilizer and liquid pig manure application treatments. pH in all soil was increased by application of liquid pig manure compared to the chemical fertilizer plot. Contents of exchangeable K in all soil were accumulated excessively by fertilization of pig manure 100% compared to the chemical fertilizer 100%. But there was no difference between the chemical fertilizer 50%+liquid pig manure 50% and chemical fertilizer 100%. No difference between the chemical fertilizer and liquid pig manure was observed in available phosphate, exchangeable Ca and Mg. $NO_3$-N concentration of infiltration water sample collected at 70cm of soil depth was lower non-fertilizer than chemical fertilizer and liquid pig manure application treatments. In volcanic ash soil, the $NO_3$-N concentration of infiltration water was decreased from early, except liquid manure 100%. In non volcanic ash soil, the $NO_3$-N concentration of infiltration water increased until October 8, but then was reduced. In all soils, $NO_3$-N concentration of infiltration water was higher in the liquid manure 100% than those in the chemical fertilizer 100% and chemical fertilizer 50%+liquid pig manure 50%, but there were no differences. In conclusion, the growth of potato, fertilization of soil and $NO_3$-N content of infiltration water were not different between chemical 50%+liquid pig manure 50% and chemical 100% plot. So, liquid pig manure could be substituted for some amount of chemical fertilizer.

• Journal of the Korean Geotechnical Society
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• v.30 no.2
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• pp.65-76
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• 2014

For soil improvement, sand mats or sand compaction piles are often constructed on soft marine clays. In such cases, some amounts of sand and clay are inevitably mixed. Sand or gravel often exists in the weathered soils near the slope surface. This research investigates the effect of mixing sand content on consistency limits and shear strength of clays. Firstly, sand was mixed with kaolinite or bentonite at 0, 9, 17, 23, 29, 33, 50% and then liquid and plastic limits were measured. Both plastic and liquid limits decreased as a sand content increased. The water content of clay-sand mixtures with different sand content increased by 10% or 20% step by step and then their undrained shear strength was measured using a portable vane shear device called Torvane. For all cases, undrained shear strength of clay-sand mixtures decreased rapidly until reaching a certain value. Their state changed from undrained to drained state gradually as the sand content increased, which caused their undrained shear strength to decrease. On the other hand, a series of direct shear tests were also conducted on such clay-sand mixtures to investigate the effect of sand content on cohesion and angle of internal friction. It was found from clay-sand mixtures that their cohesion decreased but angle of internal friction increased as the sand content increased.

• Journal of Environmental Science International
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• v.25 no.11
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• pp.1583-1587
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• 2016

The purpose of this study was to investigate the effects of fertilizer application on the content of functional materials, such as fatty acids and organic acids in perilla leaves. (1) As compared to the controlled with Ammonium sulfate fertilizer, the yield of Perilla frutescens leaves increased by 7.3% and 12.8% of biomass at 2000 and 1000 times liquid respectively, but decreased by 7.6% at 500 times. The lipid and protein contents of perilla leaves were higher than those of Portunus trituberculatus liquid at 1000 times. The average contents of minerals (mg/100g) were as follows; K (638.4) > Ca (561.6) > P (145.4) > Mg (133.5) > Fe (36.2) > Zn (1.9) > Mn (1.6) > Na (1.4 mg). However, the correlation between the controlled with P. trituberculatus liquid was relatively low. (2) The fat-soluble vitamin E content of P. frutescens leaves was 3.4, 3.9, 3.3, and 3.9 mg in the controlled with liquid by 500, and 1000, 2000 times respectively; Vitamin A contents were 6.4, 8.9, 10.9, and 8.5 mg respectively, which was more than twice as much as the corresponding vitamin E content. The water soluble vitamin C contents were 177.9, 172.6, 195.2, and 163.5 mg respectively. (3) Amino acid contents of P. frutescens leaves in 100 g of fresh weight were 3821.7 mg in the controlled with Ammonium sulfate fertilizer and 3918.8, 4054.0, and 4005.4 mg in the controlled with P. trituberculatus liquid at 2,000, 1000, 500 times respectively. Amino acid contents of each controlled group with P. trituberculatus liquid above were as small as 2.5~6.1%, and these contents of amino acid were as follows: Glutaminic acid > Aspartic acid > Leucine > Arginine > Phenylalanine. In further study, it is necessary to develop an effective microorganism and a variety of amino acid fertilizer to supplement the study on new manufacturing.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.39-47
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• 2002

This study was carried out in order to produce useful material for the forest multiple use and forest protection by soil physico-chemical analysis of studied area in Mt. Palgong. The results of soil physico-chemical analysis and statistical analysis represented as following 2 points. 1. Soil depth was in the range of average 61.1 cm and soil texture was loamy sand and sandy loam except Donghwasa area. The part of solid phase and gaseous phase were higher than other areas, but liquid phase was less in verse. Soil water content was in an average 49.5%, penetrability was average $1.95{\times}E^{-2}cm/sec$ and the average of soil hardness was $1.64Kg/cm^2$. This data showed that soil water content, penetrability and soil hardness were good at Mt. Palgong forest soils. 2. Soil pH was the range of 3.4 to 6.0, organic carbon content was 2.8% that is nearly mean of the Korea brown forest soils, total N content is somewhat smaller than that of other places, and total average C/N ratios was 13.9. Average available $P_2O_5$ concentration was 5.05 mg/kg that is lower than that of any others. The concentration of available P of coniferous forests is higher than that of deciduous forests. Exchangeable cations content is similar to those of the Korea brown forest soil and the order of the cation content extent is $Ca^{2+}$ > $Mg^{2+}$ > $Na^+$ > $K^+$.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.315-322
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• 2008

In this study, a simple, effective, and sensitive method has been developed for the quantitative residue analysis of cyhalofop-butyl and its metabolite cyhalofop acid in water and soil when kept under laboratory conditions. The content of cyholofop-butyl and cyhalofop acid in water and soil was analyzed by first purifying the compounds through liquid-liquid extraction and partitioning followed by Silica gel (adsorption) chromatography. Upon the completion of the purification step the residual levels were monitored through high-performance liquid chromatography (HPLC) using a UV absorbance detector. The recoveries of cyhalofop-butyl from three replicates spiked at two different concentrations ranged from 82.5 to 100.0% and from 66.7 to 97.9% in water and soil, respectively. The limit of detection and minimum detection level of cyhalofop-butyl in water and soil was 0.02 ppm and 10 ng, respectively. The recoveries of cyhalofop acid ranged from 80.7 to 104.8% in water and from 76.9 to 98.1 % in soil. The limit of detection of cyhalofop acid was 0.005 ppm in water and 0.01 ppm in soil, while the minimum detection level was 2 ng both in water and soil. The half-live of cyhalofop-butyl was 4.14 and 6.6 days in water and soil, respectively. The method was successfully applied to evaluate cyhalofop-butyl residues in water and soil applied aj. 30% emulsion, oil in water (EW) product.

• Journal of the Mineralogical Society of Korea
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• v.18 no.2
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• pp.93-107
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• 2005

The estuary of Nakdong River area including Noksan industrial complex and Busan New Port is composed of thick unconsolidified sediments containing abundant clay, and thus is a potential hazardous area of ground subsidence. We analyzed mineral compositions and geotechnical properties of the clay sediments that sampled from 4 boreholes of the area, and examined vertical variations and their correlations. The results showed correlations between some mineral constituents and geotechnical properties of clay sediments. A positive correlation showed between quartz content and wet unit weight, whereas a negative correlation showed between quartz content and liquid limit. Feldspar content and water content showed a negative correlation, whereas content of clay minerals and liquid limit showed a positive correlation. And also, there is a negative correlation between content of clay minerals and wet unit weight. Correlation equations are obtained from the multiple regression analyses among plastic index, content of clay mineral, smectite and clay fraction.

• Geomechanics and Engineering
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• v.15 no.5
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• pp.1091-1100
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• 2018

In this study, the relationships between hydraulic conductivity of GCLs and physico-chemical properties of bentonites were assessed. In addition to four factory manufactured GCLs, six artificially prepared GCLs (AP-GCLs) were tested. AP-GCLs were prepared in the laboratory without bonding or stitching. A total of 20 hydraulic conductivity tests were conducted using flexible wall permeameters ten of which were permeated with distilled deionized water (DIW) and the rest were permeated with tap water (TW). The hydraulic conductivity of GCLs and AP-GCLs were between $5.2{\times}10^{-10}cm/s$ and $3.0{\times}10^{-9}cm/s$. The hydraulic conductivities of all GCLs to DIW were very similar to that of GCLs to TW. Then, simple regression analyses were conducted between hydraulic conductivity and physicochemical properties of bentonite. The best correlation coefficient was achieved when hydraulic conductivity was related with clay content (R=0.85). Liquid limit and plasticity index were other independent variables that have good correlation coefficients with hydraulic conductivity (R~0.80). The correlation coefficient with swell index is less than other parameters, but still fairly good (R~0.70). In contrast, hydraulic conductivity had poor correlation coefficients with specific surface area (SSA), smectite content and cation exchange capacity (CEC) (i.e., R < 0.5). Furthermore, some post-test properties of bentonite such as final height and final water content were correlated with the hydraulic conductivity as well. The hydraulic conductivity of GCLs had fairly good correlation coefficients with either final height or final water content. However, those of AP-GCLs had poor correlations with these variables on account of fiber free characteristics.

• Journal of Mushroom
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• v.13 no.2
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• pp.139-144
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• 2015

This study was done the calculation formula for calculating the below item. That is the moisture content of the substrates raw materials, water content of the mixed substrates; the amount of media, dry weight, amount of liquid, bulk density in the bottle; dried materials volume, water volume, mixing ratio in a substrates mixing materials; water requirement amount, replenishment amount for water content control of the substrates and the total amount of substrates. And each was prepared in an Excel file for automatically calculated. The calculation of the Excel file will be able to take advantage for the mushroom growers; to make raw material costs, per bottle nutrient content and moisture content maintained throughout the year and new media composition. At this time we expect, while minimizing the quantity or deterioration in the daily ups and downs continued growing courses throughout the year contribute to stabilizing production.