• Economic and Environmental Geology
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• v.34 no.3
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• pp.271-281
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• 2001

The characteristics of the heavy metal contamination in the soils affected by the tailings of the Palbong mine have been studied. The soils in the studied area consist mostly of loam by the particle size analysis, but a little of it, located near the stream, consist of loamy sand to sandy loam, finally to loam downward. The organic contents of soils are significantly low aoom 2 percent and the pH is in acidic ranging 6.0 $\pm$ 0.1. The samples of the parent rocks, the normal soils, the tailings and the channel deposits from the studied area were chemically analysed. From the result, the heavy metal concenlration of the soils is a little Jow compared with that of the parent rocks, shows the hydrologic process of the surface and the groundwater. The contamination of the tailings from the ore mining are high in lead, copper and arsenic. In the channel deposits the concenlrations of lead and copper are abnormally high but that of arsenic is uniquely low. And most of heavy metal contamination are decreased with the distance from the mine. It is caused by the properties of the surface and the ground water during the process of the heavy metal migration. The correlation-coefficient between sand and silt contents and the concentrations of Cd, Cu and Pb are significant but the amounts of As and Hg are increased with the clay contents. The dispersion of the heavy metals with the distance shows that the concentrations of them in the soils sampled at distance of 100 m to 200 m along the stream started near the Palbong mine are extremely high compared with those from other distances. These discrepancies are significant in Cd, Cu, Pb and Hg, but low in As. All the samples contain below detection limit of Cr+6 In the present stream water the concentrations of the heavy metals are not detected. So, it is interpreted that the concentrations in the soils are caused by the activities of the mining during the operation and have been continued by the dispersion from the tailings since after the closure of the mining, especially by the surface and ground water. The concentrations are diminished with the distance from the mining site, but in the interval of 800-2000 m increases abruptly. In the soil samples counted on the dispersion direction by wind, the lowering of the concentration is relatively uniform with the distance from the mining site. So, the rapid increase of the heavy metal concentrations is presumed to have been caused by the ground-water movement. In the migration of the heavy metals, the groundwater conditions, such as pH, Eh, the contents of colloidal particles, and Mn and Fe oxides are closely involveo. Integrating with these factors, it is interpreted that the groundwater conditions which have caused the heavy metal contamination of the studied area are those that the pH is about 3 in oxidized conditions, the contents of the colloidal particles are low, and Mn and Fe oxides are not involved in the migration of the heavy metals. Meanwhile, the vegetables growing on the soils in the studied area are not affected by the contamination of the heavy metals.

• Economic and Environmental Geology
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• v.44 no.1
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• pp.71-82
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• 2011

The unsaturated soil column tests were carried out for weathered gneiss soil and weathered granite soil in order to obtain the relationship between rainfall intensity and infiltration velocity of rainfall on the basis of different unit weight conditions of soil. In this study, volumetric water content and pore water pressure were measured using TDR sensors and tensiometers at constant time interval. For the column test, three different unit weights were used as in-situ condition, loose condition and dense condition, and rainfall intensities were selected as 20 mm/h and 50 mm/h. In 20 mm/h rainfall intensity condition, average rainfall infiltration velocities for both gneiss and weathered granite soils were obtained as $2.854{\times}10^{-3}$ cm/s ~ $1.297{\times}10^{-3}$ cm/s for different unit weight values and $2.734{\times}10^{-3}$ cm/s ~ $1.707{\times}10^{-3}$ cm/s, respectively. In 50 mm/h rainfall intensity condition, rainfall infiltration velocities were obtained as $4.509{\times}10^{-3}$ cm/s ~ $2.016{\times}10^{-3}$ cm/s and $4.265{\times}10^{-3}$ cm/s ~ $3.764{\times}10^{-3}$ cm/s respectively. The test results showed that the higher rainfall intensity and the lower unit weight of soil, the faster average infiltration velocity. In addition, the weathered granite soils had faster rainfall infiltration velocities than those of the weathered gneiss soils except for the looser unit weight conditions. This is due to the fact that the weathered granite soil had more homogeneous particle size, smaller unit weight condition and larger porosity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.2
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• pp.149-157
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• 1988

This study was carried out to prepare the flavoring substance using sardine for instant soup, and to examine the taste compounds and storage stability of the product. In preparation of product, raw sardine are gutted, boiled for 10 minutes and smoked 3 times to $9{\sim}10%$ moisture content at $80^{\circ}C$ for 8 hours. The smoked-dried sardine meat were followed to be 50 mesh of particle size. The powdered-dried sardine were mixed 4.0% sugar, 20.0% table salt, 3.0% monosodium glutamate, 0.2% black pepper, 0.2% garlic powder and 0.2% onion powder, Finally the powdered instant soup product were vacuum packed in a laminated film(PET/A1 foil/CPP) bag, and then stored at room temperature for 120 days. The effect of smoking on enhancing flavor and on preventing lipid oxidation of product during storage were observed. From the chemical analysis and omission test, the principal taste compounds of product were IMP, 478.2mg/l00g; free amino acids such as glutamic acid, histidine, arginine, phenylalaine 3292.5mg/l00g; non-volatile organic acids such as lactic acid, ${\alpha}-ketoglutaric$ acid, 712.2mg/l00g; total creatinine 409.0mg/100g, and small amount of betaine, TMAO. Fatty acid composition of product were mainly consisted of polyenoic acids such as 20:5, 22:6, followed by saturated acids, monoenoic acid. The major fatty acid were 16:0, 16:1, 18:1, 20:5 and 22:6. From the results of sensory evaluation and chemical experiments during storage, the vacuum packed product were good condition for preserving the quality during storage for 120 days. We may conclude that the quality of present product was not inferior to that of seasoning powder of anchovy on the market, and it can be commercialized as a flavoring substance in preparing soup and broth.

• Ocean and Polar Research
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• v.24 no.4
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• pp.429-442
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• 2002

The faunal assembalges of macrobenthos and their habitat conditions on the soft-bottoms around Dokdo(Dok Island) was investigated using a box corer and a van Veen grab in Sept. 1999 and May 2000. The sediments in the slope sites were composed of sand particles and those in Ullneung Basin were mud. The sediments in the shelf sites were in the range of fine to medium sand. The organic content of the slope sediments was in the range of 1 to 2%. The macrobenthos occurred at the slope sites represented by 15faunal groups belonging to 8 phyla, and the major faunal group was polychaetous annelids. They comprised ca. 80.6% in slope sites, and 84.8% in shelf sites. Dominant species in the slope were Exogone verugera(40.9%), Cossura longocirrata (8.4%), Tharyx sp. (6.6%), Scalibregma inflatum (4.9%), Aedicira sp. (4.7%), Aricidea ramosa (3.8%), and Sigambra tentaculata (3.7%). Dominant species in the shelf were Chone sp. (49.3%), Tharyx sp. (18.4%), Ophelina acuminata (6.7%), Chaetozone setosa (3.8%), Glycera sp. (2.6%), and Aedicira sp. (2.4%). The mean densities of macrobenthos in the slope and shelf area were $2,028\;ind./m^2$ and $456\;ind./m^2$, respectively. The trophic composition of benthic polychaete worms in the slope area was different from that in shallow shelf area: surface deposit feeding worms were most abundant in slope area whereas filter feeding worms in shelf area. According to the cluster analysis and MDS plots, the spatial distribution of macrobenthos in Dokdo slope region was related with the sediment properties such as particle size and organic content. In the case of vertical distribution of macrobenthos in slope sites, most faunas concentrated in the upper sediment layer within 2cm depth.

• Asian Journal of Turfgrass Science
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• v.17 no.4
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• pp.155-163
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• 2003

This study was conducted to find out suitable rootzone profile, irrigation system, and turfgrass species for roof turf garden. Treatments of profile with soil amendment were Mixture I: Perlite(PL)60％＋Vermiculite(VC)20％＋Peatmoss(PM)20％, Mixture II: PL60％＋VC 10％＋PM20％＋Sand(SD)10％, Mixture III: PL60％＋VC20％＋PM20％ and Mixture IV: PL60％＋VC10％＋PM20％＋SD10％＋Styrofoam 5cm as a drain layer. To test trickle irrigation for roof garden, intervals of main pipe spacing(50cm, 100cm) and drop hole distance(15, 20, 30, 50 and 100cm)were treated, To select most suitable turfgrass species or mixture, Bermudagrass 'Konwoo', Zoysiagrass 'Konhee' and cool-season grass(Kentucky Bluegrass 80％ ＋ Perennial Ryegrass 20％, Tall Fescue 30％ ＋ KB50％ ＋ PR 20％)were tested. In particle size analysis, the soil amendments Perlite and vermiculite showed very even distribution, however, peatmoss contained mostly coarse particles with fiber over $\Phi$ 4.75mm. Under field moisture condition, vermiculite and peatmoss showed 350％ water holding capacity, on the other hand, sand or Perlite showed 115％ and 166％, respectively. Total weight of soil profile was 139.2kg/$m^2$ with Styrofoam drain layer without sand, which showed most lightest among treatments. Turf quality also resulted positve with Styrofoam drain layer installation. On trickle irrigation system, the proper interval of main drain pipe spacing and drop hole distance were 50cm and 50cm, respectively, In irrigation frequency, once per a day for 15 minute irrigation with 2 1/hr showed the best results on turf quality. Among turfgrass species or cool season grass mixture, warm season turfgrass fine leaf type zoysiagrass 'Konhee' and Bermudagrass 'Konwoo' showed very acceptable result on all over the treatments of rootzone and irrigation system. To apply cool season grasses for the roof garden, advanced researches may be needed to establish the proper soil amendment, rootzone profile, and irrigation system, Application of Bermudagrass 'Konwoo' for roof turf garden also needs successive tests to overcome winter injuries.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.8
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• pp.420-427
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• 2016

This study was conducted on the sediment remediation using micro-bubble to remove fine particles. For this study, characteristics of contamination and release in sediment were analyzed. And then, the characteristics of bubbles on removal efficiency was investigated at various operation conditions. In particle size distribution of the sediment used for the study, the proportion of clay and silt (<0.075 mm) was about 7.7%, sand (0.075~4.75 mm) was about 67.8%, and gravel (${\geq}4.75$) was 24.5%. Total nitrogen (TN) and total phosphorus (TP) of the sediment were 2,790~3,260, 261~311 mg/kg respectively. Ignition loss and water content were 4.1~9.6, 32.9~53.2% respectively. In analysis of removal efficiency according to operation conditions of micro-bubble, it was the highest when operation condition is pressure 6 atm, pressurized water ratio 30%, and coagulant dosage 15 ppm. At the time, the sediment's removal efficiency was 19.9%. Accordingly removal efficiency of TN and TP were 21.4, 22.6% respectively. Finally a research was found that fine particles in sediment were almost removed by micro-bubble, which led to decrease nutrients' release at about 20.1~64.3% in comparison to sediment including lots of fine particles.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.67-72
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• 2018

This study was conducted to investigate a potential of Yellow poplar (Liriodendron tulipifera L.) as a raw material for the manufacturing of particleboard (PB) and oriented strandboard (OSB). PB panels were prepared at the parameters of $0.7g/cm^3$ density, 15 mm thickness, three-layer, $E_1$ grade urea-formaldehyde (UF) resin, emulsion wax, and hardener. OSB panels were manufactured with a density of $0.65g/cm^3$, thickness of 10 mm, and $E_1$ grade of UF resin. Particle size of the face layer of PB was 20~80 mesh with 7~9% moisture content (MC), while that of core-layer was 3~20 mesh with 3~5% MC, which was similar to the production condition of commercial PB. As a result, the manufactured PB panels with 15.8 mm thickness, $0.7g/cm^3$ density, and 5.8% MC satisfied the requirement of bending strength of 15 type PB of Korean Industrial Standard (KS F 3104). Both internal bonding (IB) strength and surface screw withdrawal resistance also satisfied the requirement of 18 type PB of the standard. But, the edge screw withdrawal resistance satisfied the requirement of 15 type PB of the standard. These differences in properties could be due to the slenderness ratio of raw particles. In case of OSB panels with 10.7 mm thickness, $0.68g/cm^3$ density, and 5.8% MC satisfied all the requirements of bending strength, screw withdrawal resistance, and IB strength of 18 type PB of the standard. These results suggest that Yellow poplar wood has a good potential as a raw material for the production of PB and OSB.

• Journal of the Korea Concrete Institute
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• v.18 no.5 s.95
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• pp.687-693
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• 2006

The Stone Powder Sludge(below SPS) is the by-product from the process that translates stone power of 8mm under as crushed fine aggregate. It is the sludge as like cake that has average particle size of $7{\mu}m$, absorbing water content of 20 to 60%, and $SiO_2$ content of 60% over. Because of high water content of SPS, it is not only difficult to handle, transport, and recycle, but also makes worse the economical efficiency due to high energy consuming to drying. This study is aim to recycle SPS as it is without drying. Target product is the lightweight foamed concrete that is made from the slurry mixed with pulverized mineral compounds and foams through hydro-thermal reaction of CaO and $SiO_2$. Although in the commercial lightweight foamed concrete CaO source is the cement and $SiO_2$ source is high purity silica powder with $SiO_2$ of 90%, we tried to use the SPS as $SiO_2$ source. From the experiments with factors such as foam addition rate and replacement proportion of SPS, we find that the lightweight foamed concrete with SPS shows the same trends as the density and strength of lightweight foamed concrete increases according to decrease of foam addition rate. But in the same condition, the lightweight foamed concrete with SPS is superior strength and density to that with high purity silica. This trends is distinguished according to increase of replacement proportion of SPS, also the analysis of XRF shows that the hydro thermal reaction translates SPS to tobermorite. Although SPS has low $SiO_2$ contents, the lightweight foamed concrete with SPS has superior strength and density, because it reacts well with CaO due to extremely fine particles. We conclude that it is possible to replace the high purity silica as SPS in the lightweight foamed concrete experimentally.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.6
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• pp.301-306
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• 2005

Asian dust was collected in Korea and soils in the arid area of northern China were analysed for its physical and chemical properties, and mineral compositions for in order to interpret the origin of Aeolian soils and estimate the effect of dust wind on the soil environment in Korea. Asian dust was collected at Suwon in Korea from 2002 to 2004. Soil samples were collected from the desert and Loess plateaus around Gobi desert in China. As a result of analysis of desert soil distributed on northern region and Loess soils in China, it was observed that soil pH was about 9, organic matter 11 to $23g\;kg^{-1}$, and CEC 7.1 to $18.4cmolc\;kg^{-1}$, showing a high spatial variation among different sampling locations. About 62 to 80% of particles were composed of quartz and feldspars, 2 to 14% calcite ($CaCO_3$) and dolomite [$Ca{\cdot}Mg(CO_3)_2$], and trace other clay minerals. All the dust particles in Korea were below 50 m in diameter, and the mineral compositions were quartz, mica, feldspar and some clay minerals. Major components of clay mineral of Asian dust was mainly illite as compared to the kaolin of soils in Korea. The base saturation of exchangeable Ca, Mg, K and Na in the Asian dust was above 250% due to the high content calcite. Most of upland soil in Suwon was thin and sharp type, but Asian dust in Korea was the spherical shape. Asian dusts in Suwon, Korea, did not show a definite mineralogical variation of the dust during the collection period. Difference between the Asian dust collected in Korea and the soils in arid area of China was observed in the physical and chemical properties, especially for particle size distribution, cations such as Ca, Mg, K and Na. However, some similarities were found on the mineral compositions and chemical properties between Asian dust collected in Korea and the loess of China.

• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.750-756
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• 2014

This study was performed to understand the effect of cultivation periods on the physicochemical characteristics of the starch of five sweetpotato cultivars, cultivated in Muan, Korea. Starch, protein, and ash contents increased with increased cultivation period, whereas amylose content decreased. Rapid viscosity analysis showed that the pasting temperature, peak viscosity, breakdown, setback and final viscosity increased with increased cultivation period. However, trough and final viscosity decreased. Although the onset temperature and peak temperature values increased, the conclusion temperature did not show any consistent patterns by differential scanning calorimetry. X-ray diffraction showed that the starch samples had C-type crystallinity irrespective of the cultivation period and cultivar. The starch granules were dominantly round and oval, or polygonal irrespective the cultivation period. The bigger the particle size was, the longer the cultivation period was.