• Journal of the Korean Society of Clothing and Textiles
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• v.5 no.1
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• pp.9-14
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• 1981

The influence of laundering conditions on calcium deposition on the fabric was studied by repeated laundering the cotton fabric with soap in the hard water of 200 P.P.M. $CaCO_3$. The experimental variables were: 1) soap concentrations ($0.06\%$, $0.13\%$, $0.25\%$), 2) water contents in the fabric after hydroextraction. ($65\%$, $150\%$, $315\%$), 3) builders (Na-EDTA, sodium carbonate, sodium metasilicate), 4) washing cycle (5, 10, 15, 20 cycles). The fabric was washed for 15 minutes at $23\pm1^{\circ}C$ in a washing machine (Model; Gold Star Wp-2005) under the similar conditions with those of home laundering, and rinsed 5 times for 5 minutes. The amount of calcium deposits on the fabric was determined by the EDTA-Back titration method described by Wasserman and Basch. Results of this study were follows: 1) The amount of calcium deposits on the fabric increased with increasing wash cycles. 2) During the rinsing process, residual calcium content on the fabric increased with water content in the fabric after hydroextraction. 3) The amount of calcium deposits on the fabric decreased with the increasing soap concentration above the equivalent amount of calcium ion content in the water. 4) Sequestering agents and alkaline builders influenced the amount of calcium deposits on the fabric. The amount of calcium deposits on the fabric was in the order of sodium metasilicate, sodium carbonate, nonbuilder, and EDTA.

• Korean Journal of Environmental Agriculture
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• v.4 no.2
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• pp.71-77
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• 1985

Soil samples collected from paddy field adjacent to zinc-mining sites were sequentially extracted to assess chemical fractions of Cd, Zn, Cu and Pb. The purpose of this study was two fold; (i) to examine the chemical forms of heavy metal in soils by sequential extraction. and (ii) to determine relationships between the chemical distribution of heavy metal in the soil and the heavy metal content of the brown rice. The results are summarized as follows. The content of exchangeable, organically bound and carbonate Cd and residual Zn was 73.9% and 63.8% of total Cd and Zn in the soil, respectively. The content of exchangeable Cd, Zn and Pb in soil showed highly negative correlations with pH, organically bound Cd, carbonate Cd, sulfide Cd, Zn and Pb in soil showed highly positive correlations with pH. The content of organically bound Cd, Zn, Pb and carbonate Cu in soil showed highly positive correlations with organic matter content, while the content of sulfide Cu and residual Cd in soil showed highly negative correlation with organic matter content. The content of carbonate Cd, Zn, Pb and residual Cu in soil showed highly positive correlations with CEC, but the content of exchangeable Cd, Zn, Cu, Pb and organically bound Cu in soil showed highly negative correlations with CEC. The content of total, organically bound, carbonate, sulfide and residual Cd in soil were highly correlated with that of Cd in brown rice. The content of any Pb fractions in soil were not correlated with that of Pb in brown rice. The content of water soluble and exchangeable Zn in soil were highly correlated with that of Zn in brown rice.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1582-1588
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• 2005

This study aimed to evaluate the effects of silage additives on the fermentation qualities and residual mono- and disaccharides composition of silages. Forage Oats (Avena sativa L.) and Italian Ryegrass (Lolium multiflorum Lam.) were ensiled with glucose, sorbic acid and pre-fermented juice of epiphytic lactic acid bacteria (FJLB) treatments for 30 days. In both species grass silages, although the respective controls had higher contents of butyric acid (20.86, 33.45g $kg^{-1}$ DM) and ammonia-N/total nitrogen (100.07, 114.91 g $kg^{-1}$) as compared with other treated silages in forage oats and Italian ryegrass, the fermentation was clearly dominated by lactic acid bacteria. This was well indicated by the low pH value (4.27, 4.38), and high lactic acid/acetic acid (6.53, 5.58) and lactic acid content (61.67, 46.85 g $kg^{-1}$ DM). Glucose addition increased significantly (p<0.05) lactic acid/acetic acid, and significantly (p<0.05) decreased the values of pH and ammonia-N/total nitrogen, and the contents of butyric acid and volatile fatty acids as compared with control, however, there was a slightly but significantly (p<0.05) higher butyric acid and lower residual mono- and di-saccharides as compared with sorbic acid and FJLB additions. Sorbic acid addition showed the lowest ethanol, acetic acid and ammonia-N/total nitrogen, and highest contents of residual fructose, total mono- and di-saccharides and dry matter as well as high lactic acid/acetic acid and lactic acid content. FJLB addition had the lowest pH value and the highest lactic acid content, the most intensive lactic acid fermentation occurring in FJLB treated silages. This resulted in the faster accumulation of lactic acid and faster pH reduction. Sorbic acid and FJLB additions depressed clostridia or other undesirable bacterial fermentation, thus this decreased the water-soluble carbohydrates loss and saved the fermentable substrate for lactic acid fermentation.

• Journal of the Korean GEO-environmental Society
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• v.21 no.11
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• pp.21-26
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• 2020

Natural soil is composed of particles of various sizes, and the shear behavior which is a kind of mechanical behavior of the soil is affected by the particle size distribution. In addition, since the natural soil contains a large mixture of coarse and fine grained soil, it is difficult to clearly understand the shear behavior of the soil. Therefore, a ring shear test was conducted on sandy soils that has various particle size distribution in order to identify the effect of the distribution on shear characteristics of soils. At this time, sand and silt were used for coarse and fine grained soils, respectively, to make sandy soils by changing the silt content. Also the water was supplied during the test to confirm shear characteristics of sandy soils with various particle size distributions. The result shows that the shear strength increases as the silt content increases, and the strength decreases as the silt content increases over the sand. Besides, residual shear strength gradually decreases because of the silt content when the water is supplied.

• Journal of the Korean Geotechnical Society
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• v.28 no.2
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• pp.33-42
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• 2012

The purpose of this study is to determine the effect of soil grain size and its distribution on soil-water characteristic. To do this, soil-water characteristic tests were conducted on Saemangeum silt using the axis translation technique. For comparison, the test was also conducted on Jumunjin sand. Using the test results, the soil-water characteristic curves (SWCCs) of Saemangeum silt and Jumunjin sand were predicted by Van Genuchten model. By comparison and analysis between two SWCCs, the silt shows higher values of matric suction, water content, and air entry value than the sand. On the other hand, the sand has higher values of Van Genuchten model parameters of ${\alpha}$, $n$, $m$ than the silt. It indicates that the SWCC is significantly dependent on the structure of soils. In other words, if a soil has relatively high grain size and poor grain size distribution curve, the values of saturated volumetric water content, residual volumetric water content, and air entry value are small, and the variation of volumetric water content is high in accordance with the matric suction variation, and consequently it shows a narrow range of funicular region.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.1
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• pp.89-95
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• 1989

In this study, it is attempted to examine (1) the residual deformation and elastic deformation induced from the repeated loads (up to the maximum of 100,000 times) on fully compacted soil specimen, the relation between stress and strain by performing the unconfined compressive test, after repeated loads and (2) the effect of water content, dry density, number of cycle, repeated loads, etc. on the effect of the stress-strain relation. The rate of deformation caused by repeated loads greatly depends on to the condition whether the water content is above or below the plastic limit. It is possible to estimate the initial tangent modulus of soil by means of modulus of elastic deformation obtained by putting repeated loads on the clay soil.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.259-267
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• 2006

Hydraulic conductivity is the rate of water flux on hydraulic gradient. The van Genuchten Mualem (VGM) model is frequently used for describing unsaturated state of soils, that is composed with the function of soil water potential and soil water content and requests various parameters. This study is to get the value of VGM parameters used Rosetta computer program based on neural network analysis method and to calculate VGM parameters. VGM parameters included Ko(effective saturated hydraulic conductivity), ${\theta}r$(residual soil water content), ${\theta}s$(saturated soil water content), L, n and m. The unsaturated hydraulic conductivity at 10 kPa was calculated by using Rosetta program. Unsaturated hydraulic conductivities of 17 soil series at 1, 3, 5, 7 kPa were also obtained by applying saturated hydraulic conductivity by disk tension infiltrometer based on Gardner and Wooding's equation. Water flow at the water potential of 3 kPa was very low except Namgye, Hagog, Baegsan, Sangju, Seogcheon, Yesan soil series. Unsaturated hydraulic conductivity at 1 kPa showed the highest value for Samgag soil series and was in order of Yesan, Hwabong, Hagog and Baegsan soil series. Those of Gacheon, Seocheon and Ugog soil series were very low. When the value by VGM was compared with the value by disc tension infiltrometer, there was a tendency with exponential function to soils without gravel but there was no tendency to soils including gravel. Conclusively, it would be limited that VGM model for unsaturated hydraulic conductivity analysis applies to Korean agricultural land including gravel and having steep slope, shallow soil depth.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.4 s.107
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• pp.41-48
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• 2004

To make a basepaper for multipurposed seed paper, old news print (ONP) and mixed office waste paper (MOW), modified and unmodified with a commercial cellulase, were investigated. Each handsheet was applied with different chemicals such as insecticides, germicides and herbicides. The interactions behaviors of chemicals used with base papers were evaluated by means of the contents of chemicals impregnation and dissolving behaviors in water and soil. The ONP and MOW treated with the cellulase had higher impregnation and dissolving capacities in both water and soil than untreated ONP and MOW. However, the modified ONP showed lower impregnation and dissolving capacities compared to the modified MOW. The content of impregnation of chemicals would be affected with the degree of microfibrils produced by the modification treatment. Otherwise, dissolving capacities of chemicals depend on the affinity of the residual lignin in the paper.

• Journal of Welding and Joining
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• v.17 no.5
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• pp.89-96
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• 1999

The base metal and weld metal of alloy designed austenitic stainless steels were electrochemically tested in artificial sea water. Pitting resistance of 14 different stainless steels was evaluated by measuring pitting potential. The effect of alloy element to pitting potential was evaluated by changing chromium, nickel, sulfur content. The site of pitting initiation was observed by optical microscope. As a result of electrochemical test, pitting resistance of weld metal was higher than base metal, and rapidly cooled weld metal has higher pitting potential than slowly cooled weld metal. In case of primary δ-ferrite solidification, pitting potential was increased, but residual δ-ferrite was detrimental to pitting resistance. Chromium was more effective to pitting resistance than nickel, and sulfur was very detrimental element to pitting resistance.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.6
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• pp.709-715
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• 2007

The dewaterability of a sludge can be characterized by two ways: the residual moisture content in the sludge cake after dewatering process, and the filtration of the sludge. Time to filter (TTF) represents filtration processes that are special cases of the flow through a solid matrix concept. TTF characterizes a resistance to filtration. The sludge resistance, in turn, can be subdivided into resistances associated with the solid phase and the liquid phase to evaluate the effect of each of the two phases on sludge dewaterability. In order to determine the dewatering characteristics of the water sludge samples, TTF and zeta potential were measured. For these studies cationic polymer was chosen for water sludge dewatering experiments. The zeta potential of thickener sludges neared from minus values to zero values till 4 days after sampling. The dewaterability of thickener sludges using cationic polymer was deteriorated according to the increase of detention time. As the detention time was increased from 4 to 10 days, the optimal dose of the polymer was increased from 4 to 8mg/L. Therefore, the optimal detention time plays an important part for the dewaterability of a sludge.