• Journal of the Korean Society of Groundwater Environment
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• v.7 no.1
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• pp.55-58
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• 2000

Methyl tertiary butyl ether (MTBE) is a gasoline additive that boosts the oxygen content in fuel (an oxygenate), resulting in less air-polluting carbon monoxide being released from vehicle exhaust systems. Then, groundwater contamination problems have been developed in areas where the chemical is used. Common sources of water contamination by MTBE include leaking underground gasoline storage tanks and leaks and spills from above ground fuel storage tanks, etc.. Studies on the chemical and these problems are going on abroad vigorously. These studies should be performed in our country as well more actively. This paper reviews on articles on these studies and focuses on the identification of the chemical as a groundwater contamination source.

• Research in Plant Disease
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• v.21 no.1
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• pp.36-39
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• 2015

In June 2012 and 2013, a destructive stem rot symptoms of Ligularia fischeri occurred sporadically in Hoengseong-gun and Pyeongchang-gun Gangwon-do, Korea. The typical symptom included water-soaking on the main stem, rotting, wilting and blighting, which eventually leads to death of the plant. White mycelial mats were spread over lesions and brown sclerotia were formed on stems and near soil surface. The sclerotia were white to brown, spherical or irregular, 1-3 mm in size on potato dextrose agar (PDA), The optimum temperature range of hyphal growth was $25-30^{\circ}C$ and the hyphal diameter was $4-10{\mu}m$. The typical clamp connections were observed in the hyphae of the fungus grown on PDA. The resulting sequence of 695 bp was deposited in GenBank. A BLAST search revealed that sequences of the this isolates showed >99% identity with those of Sclerotium rolfsii. On the basis of the morphological characteristics and phylogenetic analyses of molecular markers ITS rDNA, the fungi were identified as S. rolfsii. A pathogenicity test was carried out to fulfill Koch's postulates. To our knowledge, this is the first report of S. rolfsii on Ligularia fischeri in Korea.

• Korean Journal of Environmental Agriculture
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• v.11 no.1
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• pp.41-49
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• 1992

To determine the efficacy of uniconzaole[(E)-1-(4-chlorophenyl)-4,4-dimethy 2-(1,2,4-triazol-1-yl)-1-penten-3-ol)](XE-1019) as a phytoprotectant against $O_3$ injury in tomato plants(Lycopersicon esculentum Mill. 'Pink Glory'), plants were given a 50ml soil drench of uniconazole solution at concentrations of 0.001, 0,01, 0.1 and 0.2mg/pot thirteen days prior to $O_3$ fumigation. All four uniconazole concentrations were effective in providing protection against $O_3$ exposure(16h at 0.3 ppm). Uniconazole treatment above 0.001 mg/pot significantly reduced stem elongation, leaf enlargement, leaf area and fresh weight of plant, whereas increased chlorophyll concentration. Transpiration rate on a whole plant basis was reduced by uniconazole treatment and $O_3$ exposure. Uniconazole reduced ethylene production induced by $O_3$ injury but had little or no effect on defoliation of cotyledons and leaf epinasty. Activities of peroxidase (POD) and superoxide dismutase(SOD) were slightly increased by application of uniconazole. With increasing exposure time, $O_3$ increased POD activity but decreased SOD activity. The phytoprotective effects of uniconazole were diminished by applying gibberellin at $10{\sim}20$ ppm. These results suggest that the phytoprotective effects of uniconazole are related to its role of increasing activities of free radical scavengers such as POD and SOD, in addition to growth-retardation as an anti-gibberellin.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.473-484
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• 2016

This study aims to establish a monitoring method for managing the effective maintenance of tailings dams. The monitoring of a tailings dump area involves several parameters and their investigation through a selection of evaluation items. The extents of defects and progressive failures also need to be effectively estimated. Therefore, the monitoring items can be subdivided into categories relating to the retaining wall structure (concrete wall, reinforcing stone wall, mesh gabions) and general facilities (liner, covering soil, slope, tailings, rain protection facility, leachate, planting), and quantitative evaluations can then be conducted for each condition. In doing so, we developed a systematic monitoring method that assesses the dam maintenance condition with grades and scores. The field application of the monitoring method results showed it to provide a more detailed evaluation than existing monitoring methods: the method detected an additional 16 defects missed by conventional methods. The evaluation gave scores of 89.3, 22.2, and 27.8 to the Geumjang mine tailings dam, the Gupoong mine tailings dam, and the Hwachun mine tailings dam, respectively. The advanced method can provide quantitative evaluation and perform detailed monitoring of the dams. This quantitative evaluation can be used to decide on maintenance priorities, select the main management items, and establish schedules of maintenance.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.5
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• pp.236-241
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• 2016

This study conducted a screening-level ecological risk assessment for heavy metals in dredged sediment for recycling in terrestrial environment. Toxicological information of six heavy metals (i.e., Cu, Zn, Cd, Pb, Cr, and Ni) was collected from ECOTOX of US Environmental Protection Agency, and screened and qualified for the use in the screening-level ecological risk assessment. According to the number of terrestrial ecological receptors for which toxicological information is available, PNEC (Predicted No Effect Concentration) of each heavy metal was derived using either stochastic approach (for Cu, Zn, and Cd), or deterministic approach (for Pb, Cr, and Ni). Hazard quotients of the six heavy metals were derived for a field-collected dredged sediment using the PNEC derived and the PEC (Predicted Environmental Concentration) determined for the dredged sediment. The HQs of Cu, Zn, Cr, Pb and Ni were higher than unity indicating a possibility of ecological risk of the five heavy metals when the dredged sediment is applied in terrestrial environment. Accordingly, remediation processes or a higher-level ecological risk assessment would be needed for the recycling of the material.

• Journal of Forest and Environmental Science
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• v.36 no.3
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• pp.207-218
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• 2020

Ashwagandha is an important ancient medicinal crops, being affected with many diseases, among which leaf blight caused by Alternaria alternata has become the constraint resulting in huge yield losses. Continuous usage of chemical methods leads to environment, soil and water pollution. Whereas biological control of diseases is long lasting, inexpensive, eco-friendly and harmless to target organisms. In this context, it is aimed to evaluate five Trichoderma strains viz. Trichoderma virens IMI-392430, T. pseudokoningii IMI-392431, T. harzianum IMI-392432, T. harzianum IMI-392433 and T. harzianum IMI-392434 as bio-control efficacy against A. alternata and growth promoting effect in Ashwagandha. All the Trichoderma strains had varied antagonistic effects against the pathogen. In dual culture technique, the strain T. harzianum IMI-392433 showed maximum percentage inhibition of mycelial growth (54.89%) followed by T. harzianum IMI-392432 (53.83%), T. harzianum IMI-392434 (48.94%) and T. virens IMI-392430, (43.62%) against the pathogen, while the least inhibition percentage was observed with the T. pseudokoningii IMI-392431 (36.60%). The culture filtrate of the Trichoderma strain, T. harzianum IMI-392433 recorded highest inhibition on the mycelial growth (39.05%) and spore germination (80.77%) of pathogen and the lowest was recorded in T. pseudokoningii IMI-392431 (20.45 and 50%). Moreover, seeds treated with spore suspension of the strain T. harzianum IMI-392433 reduced the percentages of disease severity index significantly. The strain T. harzianum IMI-392433 also significantly increased seed germination %, seedling vigor and growth of Ashwagandha. The correlation matrix showed that root yield per plant of Ashwagandha had significant and positive correlation with plant height (r=0.726^⁎⁎), number of leaf (r=0.514^⁎⁎), number of primary branch (r=0.820^⁎⁎), number of secondary branch (r=0.829^⁎⁎), fresh plant weight (r=0.887^⁎⁎), plant dry weight (r=0.613^⁎⁎), root length (r=0.824^⁎⁎), root diameter (r=0.786^⁎⁎), root dry weight (r=0.739^⁎⁎) and fresh root weight (r=0.731^⁎⁎). The significant and negative correlation (r=-0.336^⁎⁎) was observed with the root yield and percentages of disease severity index. The study recognized that the T. harzianum IMI-392433 strain performed well in inhibiting the mycelial growth and reduced the percentages of disease severity index of pathogen as well as increased the plant growth in Ashwagandha.

• Journal of Environmental Science International
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• v.27 no.4
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• pp.241-250
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• 2018

The objective of this study was to estimate air quality trends in the study area by surveying monthly and seasonal concentration trends. To do this, the mass concentration of $PM_{10}$ samples and the metals, ions, and total carbon in the $PM_{10}$ were analyzed. The mean concentration of $PM_{10}$ was $33.9{\mu}g/m^3$. The composition of $PM_{10}$ was 39.2% ionic species, 5.1% metallic species, and 26.6% carbonic species (EC and OC). Ionic species, especially sulfate, ammonium, and nitrate, were the most abundant in the $PM_{10}$ and had a high correlation coefficient with $PM_{10}$. Seasonal variation of $PM_{10}$ showed a similar pattern to those of ionic and metallic species. with high concentration during the winter and spring seasons. $PM_{10}$ showed high correlation with the ionic species $NO_3{^-}$ and $NH_4{^+}$. In addition, $NH_4{^+}$ was highly correlated with $SO{_4}^{2-}$ and $NO_3{^-}$. We obtained four factors through factor analysis and determined the pollution sources using the United States Environmental Protection Agency(U.S. EPA) pollution profile. The first factor accounted for 51.1% of $PM_{10}$ from complex sources, that is, soil, motor vehicles, and secondary particles: the second factor indicated marine sources; the third factor, industry-related sources; and the last factor, heating-related sources. However, the pollution profile used in this study may be somewhat different from the actual situation in Korea because it was from US EPA. Therefore, to more accurately estimate the pollutants present, it is necessary to create a pollution profile for Korea.

• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.73-83
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• 2005

This study was carried out to investigate control efficacy of fungicides mixed with pyroligneous acid on Large patch caused by Rhizoctonia solani AG2-2. R. solani AG2-2 was not inhibited by concentration of 500 times and 1,000 times diluents of pyroligneous acid. It is thought that R. solani AG2-2 was not inhibited by Pyroligneous acid alone. Pencycuron and tebuconazol mixed with pyroligneous acid had a good effect in prevention of R. solani AG2-2 in zoysiagrass. Concurrently, it was observed that those were reduced $50\%$ of usage of fungicides. 500 times and 1,000 times diluents of pyroligneous acid treated group had a significantly effect compared to control turf in the leaf length, leaf width and dry weight. In conclusion, usage of fungicides could be reduced about $50\%$ by a fungicides mixed with pyroligneous acid for protection of R. solani AG2-2. Therefore, It is thought that fungicides mixed with pyroligneous acids can be reduced an economic load and also an environmental pollution such as a tolerance to pathogenic bacteria and a destruction of an ecological system of soil microbes according to use fungicides.

• Smart Structures and Systems
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• v.4 no.2
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• pp.221-232
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• 2008

This paper represents the final results of a research program sponsored by the European Commission through project WIND-CHIME ($\underline{W}$ide Range Non-$\underline{IN}$trusive $\underline{D}$evices toward $\underline{C}$onservation of $\underline{HI}$storical Monuments in the $\underline{ME}$diterranean Area), in which the possibility of using advanced seismic protection technologies to preserve historical monuments in the Mediterranean area is investigated. In the current research, the dynamic characteristics of two outstanding Mamluk-Style minarets, which similar minarets were reported to experience extensive damage during Dahshur 1992 earthquake, are investigated. The first minaret is the Qusun minaret (1337 A.D, 736 Hijri Date (H.D)) located in El-Suyuti cemetery on the southern side of the Salah El-Din citadel. The minaret is currently separated from the surrounding building and is directly resting on the ground (no vaults underneath). The total height of the minaret is 40.28 meters with a base rectangular shaft of about 5.42 ${\times}$ 5.20 m. The second minaret is the southern minaret of Al-Sultaniya (1340 A.D, 739 H.D). It is located about 30.0 meters from Qusun minaret, and it is now standing alone but it seems that it used to be attached to a huge unidentified structure. The style of the minaret and its size attribute it to the first half of the fourteenth century. The minaret total height is 36.69 meters and has a 4.48 ${\times}$ 4.48 m rectangular base. Field investigations were conducted to obtain: (a) geometrical description of the minarets, (b) material properties of the minarets' stones, and (c) soil conditions at the minarets' location. Ambient vibration tests were performed to determine the modal parameters of the minarets such as natural frequencies and mode shapes. A $1/16^{th}$ scale model of Qusun minaret was constructed at Cairo University Concrete Research Laboratory and tested under free vibration with and without SMA wire dampers. The contribution of SMA wire dampers to the structural damping coefficient was evaluated under different vertical loads and vibration amplitudes. Experimental results were used along with the field investigation data to develop a realistic 3-D finite element model that can be used for seismic risk evaluation of the minarets. Examining the updated finite element models under different seismic excitations indicated the vulnerability of such structures to earthquakes with medium to high a/v ratio. The use of SMA wire dampers was found feasible for reducing the seismic risk for this type of structures.

• Journal of architectural history
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• v.20 no.3
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• pp.7-22
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• 2011

With the accumulations of outcomes from archaeological excavations of mountain fortress of three kingdoms period, there have been studies about time-periodic territory range of mountain fortress, difference in the way(method) of construction, defence system and so on from various points of view. This is an empirical study on the construction method of the valley part of stone fortress. First of all, it is required to secure large quantity of fresh water for those who lived at mountain fortress. Especially when builders of fortress construct a fortification at the valley part of stone fortress, in advance they must sufficiently consider several options including the establishment of sustainable water resources. First, when it comes to build a fortification on a ridge[or a slope] of a mountain, you have only to consider a vertical stress. However, when it comes to build a fortification at the valley part of a mountain, You must have more sufficient preparations for the constructing process. Because there are not only a vertical stress but also a horizontal pressure simultaneously. Second, a fortification of mountain fortress built by using unit building stone is a structure of masonry construction like brick construction, and the valley part of it is where the construction of the fortification begins. Third, when it comes to build a fortification at the valley part of a mountain, it seems that they use a temporary method such as coffer dam in oder to prevent the collapse of the fortification due to heavy rain. Furthermore, in response to a horizontal pressure a fortification is built by the way of its plane make an arch, or by piling up the soil with the plate method(類似版築) and earthen wall harder method(敷葉) they increase cross-sectional area of the fortification and its cutoff capacity. In front direction they put the reservoir facility for the fear that the hydraulic pressure and earth pressure are directly transmitted to the fortification. The process of constructing the fortification at the valley part of a mountain is done in the same oder as follows; leveling of ground(整地) ${\Rightarrow}$ construction of coffer dam ${\Rightarrow}$ construction of the fortification between the both banks of the valley ${\Rightarrow}$ construction of the fortification at bottom part of spill way(餘水路) between the both banks of the valley ${\Rightarrow}$ construction of spill way(餘水路) & reservoir facility ${\Rightarrow}$ construction of the fortification at upper part of spill way between the both banks of the valley. Coffer dam facility seems to be not only the protection device on occasion of flood but also an important criterion to measure the proper height of spill way or tailrace(放水路). This study has a meaningful significance in that it empirically examines the method of reduction of the horizontal pressure which the fortification at the valley part of a mountain takes, the date the construction was done, and wether the changes in climate such as heavy rainfall influence the process of construction.