• Journal of Bio-Environment Control
• /
• v.21 no.4
• /
• pp.336-342
• /
• 2012

Inorganic materials were commonly used as container media in domestic plant factories. Objective of this research was to secure the information in soil physical and chemical properties of inorganic materials such as vermiculites and perlites. To achieve this, 12 gold and silver vermiculites from China, Zimbabwe, and South Africa and 5 perlites from China were collected based on the marketing grades (MG) in particle sizes and analyzed for determination of their characteristics. The percentage of particles larger than $710{\mu}m$, in China perlite MG 3~5 mm, China silver vermiculites MG > 8 mm and MG 3~8 mm were 99.9%, 99.8%, and 99.7%, respectively, which were much higher than 28.4% in China gold vermiculite MG 0.3~1.0 mm, 14.0% in perlite MG < 1.0 mm, and 12.6% of Zimbabwe silver vermiculite MG < 1.0 mm. The container capacities of perlite MG < 1.0 mm and South Africa silver vermiculite MG 0.25~1.0 mm were 72.0% and 71.1%, respectively. The air space in China silver vermiculite MG 3~8 mm was 49.3% which was higher than other materials tested. However, the China gold and silver vermiculites MG 0.3~1 mm had 3.5% and 2.4% in air space indicating that possible problems could occur in soil aeration when they are used for container media. The percentage of easily available and buffering water of China gold vermiculite MG 0.3~1 mm and perlite MG < 1.0 mm were the highest among test materials. The ranges of pH and electrical conductivity were 6.36 to 10.7 and 0.032 to $0.393dS{\cdot}m^{-1}$ in vermiculites and 7.78 to 8.62 and 0.030 to $0.041dS{\cdot}m^{-1}$ in perlite, respectively. The cation exchange capacity of China silver vermiculite MG 0.3~1 mm were $14.7cmol{\cdot}kg^{-1}$ that was 10 times as high as $0.34cmol{\cdot}kg^{-1}$ in perlite MG 1~2.5 mm. The vermiculites had the higher contents of exchangeable cations such as Ca, K, and Na, than those of perlites.

• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.1
• /
• pp.56-61
• /
• 1997

A study was carried out to find out the basic information in physical properties for selection and manufacturing the good seedling media through the analysis of the physical properties, such as particle size, water retention and three phases of the major horticultural substrates. Easily available water(EAW), the water contents between 1kPa and 5kPa water potental, was highest in peatmoss with 39%, and perlite 34.0%, vermiculite 16.9%, but the values of osmunda and bark were lower than 4.8%. Water buffering capacity(WBC), the water content between 5kPa and 10kPa, was 6.1% in peatmoss and 2.3% in vermiculite but it was lower than 1.0% in other substrates. To adjust the suitable range of water potential at crossing point of water and air curves to 1.5~2.5kPa, more finer materials were needed in osmunda and bark, and more coarser materials must be added to peatmoss, perlite and vermiculite. Water potentials of substrates in saturated pot condition were equivalent to 2.2kPa in peatmoss and others were ranged in 1.0kPa to 4.3kPa of water potential in pressure chamber.

• Journal of Life Science
• /
• v.18 no.4
• /
• pp.515-521
• /
• 2008

This experiment was conducted to investigate effects of non-ionic or zwitterionic (+/-) surfactants on digestibility of rice straw, and changes of growth of rumen mixed microbes, pH, and gas production during in vitro fermentation. Also, during in vitro ruminal fermentation, microbial attachment on rice straw was investigated using scanning electron microscopy (SEM). Tween 80 or SOLFA-850 for non-ionic surfactant (NIS), and 3-(Dodecyldimethylammonio) propanesulfanate (DDAP) for zwitterionic surfactant (ZIS) was supplemented by 0.05% and 0.1% in Dehority's artificial medium containing Holtein rumen fluid, respectively, and the substrate for fermentation was rice straw passed through 1 mm screen. The experiment was composed of 7 treatments (two levels of two NISs, two levels of a ZIS) including the control, and 6, 12, 24, 48 and 72 hr of fermentation time with 3 replications per treatment. Treatment of Tween 80 increased in vitro DM digestibilities during 48 hr and 72 h post fermentations compared to the other treatments, whereas treatment of DDAP as a ZIS resulted in decreased DM digestibility than that of the control from 24 hr post fermentation (P<0.05). Gas production in vitro was greater (P<0.05) with addition of NIS than the control or ZIS, and increased as fermentation time elapsed. Rumen mixed microbial growth was greatest with addition of Tween 80 as NIS, and lowest when DDAP as ZIS was supplemented to the fermentation tube (P<0.05). In SEM observation, rumen microbial population attached on rice straw particle was greater with addition of NIS, but was less with addition ZIS compared with the control. In conclusion we could not found any positive effects of ZIS surfactants on rumunal fermentation characteristics and rumen microbial growth rates.

• Korean Journal of Remote Sensing
• /
• v.37 no.6_2
• /
• pp.1793-1801
• /
• 2021

From 2015 to June 2020, the backscattering coefficients of 532 and 1064 nm measured using LIDAR and the depolarization ratio at 532 nm were used to separate the backscattering coefficient at 532 nm as three types as PM₁₀, PM_2.5-10, PM_2.5 according to particle size. The mass extinction efficiency (MEE) of three types was calculated using the mass concentration measured on the ground. The overall mean values of the calculated MEE were 5.1 ± 2.5, 1.7 ± 3.7, and 9.3 ± 6.3 m²/g in PM₁₀, PM_2.5-10, and PM_2.5, respectively. When the mass concentration of PM₁₀ and PM_2.5 was low, higher than average MEE was calculated, and it was confirmed that the MEE decreased as the mass concentration increased. When the MEE was calculated for each type according to the mixing degree of Asian dust, PM_2.5-10 was twice at pollution aerosol as high as 2.1 ± 2.8 m²/g, compare to pollution-dominated mixture, dust-dominated mixture, and pure dust of 1.1 ± 1.8, 1.4 ± 3.3, 1.1 ± 1.5 m²/g, respectively. However, PM_2.5 MEE showed similar values irrespective of type: 9.4 ± 6.5, 9.0 ± 5.8, 10.3 ± 7.5, and 9.1 ± 9.0 m²/g. The MEE of PM₁₀ was 5.6 ± 2.9, 4.4 ± 2.0, 3.6 ± 2.9, and 2.8 ± 2.4 m²/g in pollution aerosol (PA), pollution-dominated mixture (PDM), dust-dominated mixture (DDM), and pure dust (PD), respectively, and increased as the dust ratio value decreased. Even if the same type according to the same mass concentration or Asian dust mixture was shown, as the PM_2.5/PM₁₀ ratio decreased, the MEE of PM_2.5-10 decreased and the MEE of PM_2.5 showed a tendency to increase.

• Korean Journal of Heritage: History & Science
• /
• v.50 no.4
• /
• pp.148-165
• /
• 2017

Mural paintings drawn inside ancient tombs are very sensitive to changes in the environment such as temperature and humidity, especially the finish layer of the tomb murals differ in preservability depending on the material properties and humidity conditions. In this study, I examined the mural painting of Songsan-ri Tomb No.6, where the finish layer was made of earth, and identified the physical changes that can occur due to drying, depending on the material properties of the finish layer. I found out through particle size analysis that the finish layer of the mural painting in Songsan-ri Tomb No.6 is about 85.0wt% below silt, about 14.0wt% clay therein, mostly composed of silt and below clay. I also found out through physical property evaluation that surface change rate of samples showed the largest change at 15.5% in reproduced finish layer sample made up of bentonite, followed by 7.8% of reproduced finish layer sample made up of celadon soil, 6.3% of reproduced finish layer sample made up of loess, 6.2% of reproduced finish layer sample composed of white clay and the same order of change in appearance was confirmed in each sample consisted of soil. In addition, it showed the same trend of surface change rate, and the bentonite condition showed the largest change, in the measurement of shrinkage rate and expansion rate. The experiment shows that the finish layer composed of soil is affected by cohesion among particles according to the content of fine parts and the relationship between the agglomeration due to the content of the differentiated part and the stress due to the expansibility depending on the kind of the clay mineral etc. Therefore, it can be concluded that the physical damage occurred in the mural painting finish layer of the Songsan-ri Tomb No.6 is related to the factors such as the material characteristics of the soil and the highly humid environmental change inside the tomb.

• Economic and Environmental Geology
• /
• v.54 no.6
• /
• pp.717-731
• /
• 2021

We analyzed the characteristics of the habitat environment for the Seonam study area in Ulsan, the southern shore of the East Sea using bathymetry and seafloor environment data. The depth of the study area ranges from about 0 m to 23 m. In the west of the study area, the water depth is shallow with a gentle slope, and the water depth becomes deeper with a steep slope in the east. Due to the right-lateral strike-slip faults located in the continental margin of the East Sea, the fracture surfaces of the seabed rocks are mainly in the N-S direction, which is similar to the direction of the strike faults. Three seafloor types (conglomeratic-grained sandy, coasre-graiend sandy, fine-grained sandy) and rocky bottom area have been classified according to the analyses of the bathymerty, seafloor image, and surface sediment data. The rocky bottom areas are mainly distributed around Seaoam and in the northern and southern coastal area. But the intermediate zone between Seonam and coastal area has no rocky bottom. This intermediate area is expected to have active sedimentation as seawater way. The sandy sediments are widely distributed throughout the study area. Underwater images and UAV images show that Cnidarians, Brachiopods, Mollusks are mostly dominant in the shallow habitat and various Nacellidae, Mytilidae live on the intertidal zone around Seonam. Annelida and Arthropod are dominant in the sandy sediments. The distribution of marine organism in the study area might be greatly influenced by the seafloor type, the composition and particle size distribution of the seafloor sediments. The analysis of habitat environment mapping with bathymetry, seafloor data and underwater images is supposed to contribute to the study of the structure and function of marine ecosystem.

• Korean Journal of Mineralogy and Petrology
• /
• v.36 no.1
• /
• pp.55-72
• /
• 2023

This study aims to identify the fault zone architecture and geometric and kinematic characteristics of the Yeongdeok Fault, based on the geometry and kinematic data of various structural elements obtained by detailed field survey and anisotropy of magnetic susceptibility (AMS) of the fault rocks. The Yeongdeok Fault extends from Opo-ri, Ganggu-myeon, Yeongdeok-gun to Gilgok-ri, Maehwa-myeon and Bangyul-ri, Giseong-myeon, Uljin-gun, and cuts various rock types from the Paleo-proterozoic to the Mesozoic with a range of 4.6-5.0 km (4.77 km in average) of right-lateral offset or forms the rock boundaries. The fault is divided into four segments based on its geometric features and shows N-S to NNW strikes and dips of an angle of ≥ 54° to the east at most outcrops, even though the outcrops showing the westward dipping (a range of 54°-82°) of fault surface increase as it goes north. The Yeongdeok Fault shows the difference in the fault zone architecture and in the fault core width ranging from 0.3 to 15 m depending on the bedrock type, which is interpreted as due to differences in the physical properties of bedrock such as ductility, mineral composition, particle size, and anisotropy. Combining the results of paleostress reconstruction and AMS in this and previous studies, the Yeongdeok Fault experienced (1) sinistral strike-slip under NW-SE maximum horizontal principle stress (σ_Hmax) and NE-SW minimum horizontal principle stress (σ_Hmin) in the late Cretaceous to early Cenozoic, and then (2) dextral strike-slip under NE-SW maximum horizontal principle stress (σ_Hmax) and NW-SE minimum horizontal principle stress (σ_Hmin) in the Paleogene. It is interpreted that the deformation caused by the Paleogene dextral strike-slip movement was the most dominant, and the crustal deformation was insignificant thereafter.

• Korean Journal of Environmental Biology
• /
• v.40 no.2
• /
• pp.125-137
• /
• 2022

To assess the characteristics of meiofaunal community fluctuations related to environmental factors, seasonal surveys were conducted in the subtidal zone of Hallyeohaesang National Park. The average depth of the study area was about 20 m, and the average water temperature at the bottom was low in winter(11.33℃) and high in summer(17.95℃). The sedimentary particles mainly comprised silt and clay at most stations. The abundance of meiofauna ranged from 81.7 to 1,296.5 Inds. 10 cm^-2, and the average abundance was 589.3 Inds. 10 cm^-2. The average abundance of meiofauna in each season was the lowest at 416.5 Inds. 10cm^-2 in winter and the highest at 704.5Inds.10 cm^-2 in spring. The dominant taxa were nematodes (about 92%) and harpacticoids (about 5%). In the cluster analysis of meiofaunal communities, they were divided into four significant groups. The largest group mainly contained spring and summer samples, and contained stations with a high nematode density of over 500 Inds. 10 cm^-2 and harpacticoids below 50 Inds. 10 cm^-2 with a high composition ratio of nematodes. In the cluster analysis, no regional division was found between the stations, and it was thought to be divided by the seasons with high abundance according to seasonal variation and the composition ratio of nematodes and harpacticoids. In the Spearman rank correlation analysis, the density of total meiofauna and the most dominant taxa, nematodes, was not significantly related to environmental factors. However, the density of harpacticoids had a significant positive correlation with water depth and a negative correlation with sediment particle size.

• Journal of Korea Water Resources Association
• /
• v.56 no.12
• /
• pp.919-928
• /
• 2023

Rainfall characteristics in Korea are concentrated during the summer flood season. In particular, when a large amount of turbid water flows into the dam due to the increasing trend of concentrated rainfall due to abnormal rainfall and abnormal weather conditions, prolonged turbid water phenomenon occurs due to the overturning phenomenon. Much research is being conducted on turbid water prediction to solve these problems. To predict turbid water, turbid water data from the upstream inflow is required, but spatial and temporal data resolution is currently insufficient. To improve temporal resolution, the development of the Turbidity-SS conversion equation is necessary, and to improve spatial resolution, multi-item water quality measurement instrument (YSI), Laser In-Situ Scattering and Transmissometry (LISST), and hyperspectral sensors are needed. Sensor-based measurement can improve the spatial resolution of turbid water by measuring line and surface unit data. In addition, in the case of LISST-200X, it is possible to collect data on particle size, etc., so it can be used in the Turbidity-SS conversion equation for fraction (Clay: Silt: Sand). In addition, among recent remote sensing methods, the spatial distribution of turbid water can be presented when using UAVs with higher spatial and temporal resolutions than other payloads and hyperspectral sensors with high spectral and radiometric resolutions. Therefore, in this study, the Turbidity-SS conversion equation was calculated according to the fraction through laboratory analysis using LISST-200X and YSI-EXO, and sensor-based field measurements including UAV (Matrice 600) and hyperspectral sensor (microHSI 410 SHARK) were used. Through this, the spatial distribution of turbidity and suspended sediment concentration, and the turbidity calculated using the Turbidity-SS conversion equation based on the measured suspended sediment concentration, was presented. Through this, we attempted to review the applicability of the Turbidity-SS conversion equation and understand the current status of turbid water occurrence.

• Korean Journal of Soil Science and Fertilizer
• /
• v.43 no.2
• /
• pp.230-236
• /
• 2010

Jeju Island is a volanic island which is located about 96 km south of Korean Peninsula. Volcanic ejecta, and volcaniclastic materials are widespread as soil parent materials throughout the island. Soils on the island have the characteristics of typical volcanic ash soils. This study was conducted to reclassify Jeju series based on the second edition of Soil Taxonomy and to discuss the formation of Jeju series in Jeju Island. Morphological properties of typifying pedon of Jeju series were investigated, and physico-chemical properties were analyzed according to Soil survey laboratory methods manual. The typifying pedon has dark brown (10YR 3/3) silt clay loam A horizon (0~22 cm), strong brown (7.5YR 4/6) silty clay BAt horizon (22~43 cm), brown (7.5YR 4/4) silty clay Bt1 horizon (43~80 cm), brown (7.5YR 4/6) silty clay loamBt2 horizon (80~105 cm), and brown (10YR 5/4) silty clay loam Bt3 horizon (105~150 cm). It is developed in elevated lava plain, and are derived from basalt, and pyroclastic materials. The typifying pedon contains 1.3~2.1% oxalate extractable (Al + 1/2 Fe), less than 85%phosphate retention, and higher bulk density than 0.90 Mg $m^{-3}$. That can not be classified as Andisol. But it has an argillic horizon from a depth of 22 to 150 cm, and a base saturation (sum of cations) of less than 35% at 125 cm below the upper boundary of the argillic horizon. That can be classified as Ultisol, not as Andisol. Its has 0.9% or more organic carbon in the upper 15 cm of the argillic horizon, and can be classified as Humult. It dose not have fragipan, kandic horizon, sombric horizon, plinthite, etc. in the given depths, and key out as Haplohumult. A hoizon (0~22 cm) has a fine-earth fraction with both a bulk density of 1.0 Mg $cm^{-3}$ or less, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0. Thus, it keys out as Andic Haplohumult. It has 35% or more clay at the particle-size control section, and has thermic soil temperature regime. Jeju series can be classified as fine, mixed, themic family of Andic Haplohumults, not as ashy, thermic family of Typic Hapludands. In the western, and northern coastal areas which have a relatively dry climate in Jeju Island, non Andisols are widely distributed. Mean annual precipitation increase 110 mm, and mean annual temperature decrease $0.8^{\circ}C$ with increasing elevation of 100m. In the western, and northern mid-mountaineous areas Andisols, and non Andisols are distributed simultaneously. Jeju series distributed mainly in the western and northern mid-mountaineous areas are developed as Ultisols with Andic subgroup.