• Clean Technology
• /
• v.7 no.4
• /
• pp.251-263
• /
• 2001

This study was conducted to provide a basic information for recovery plan of Seung-Gi Stream which is a major stream of Incheon metropolitan area. Source and characteristics of pollutants were analyzed and studied. Samples were taken 10 rounds in 5 sections in Seung-Gi stream. Annual pollutants loads and sectional characteristics of pollutants loads were investigated regarding flow rate, pH, DO, SS, $BOD_5$, $COD_{Cr}$, T-P, TKN and concentrations of Zn, Cd, Cu, Cr atoms which enter into Seung-Gi stream during rainy and dry season respectively. As one came close to the Nam-Dong Industrial Complex, sectional discharge loads were heavy and water quality was failed to meet the standard by "Environmental Standard of River Quality". As a result, heavy load of pollutants in Seung-Gi stream was considered to influence negatively the sea water quality of Incheon. Solution plans to solve problems are as follows. First, circulation of treated water at Seung-Gi WWTP(Wastewater Treatment Plant) and retreated water by URC(ultra rapid coagulation) process treat with that. Second, sewage and wastewater is gathered, make it disposed. After then, we circulate treated water. If solution plans be applied, we can predict water quality. Then we could grope for how make to recovery role of Seung-Gi stream as stream.

• Journal of the Korean Geotechnical Society
• /
• v.30 no.5
• /
• pp.25-35
• /
• 2014

The sedimentary rocks exposed around Mt. Palgong were subjected to metamorphism due to a granitic magma intrusion at late Cretaceous, and they eventually metamorphosed to hornfels by the action of both hydrothermal solution and high temperature supplied from the magma. The hornfels zone around the granite body ranges from 2.0 to 3.5 km in width but the boundary between hornfels and sedimentary rocks is not obviously defined because the metamorphic grade gradually decreases with distance from the granite boundary. A series of laboratory tests on 350 core specimens made by 35 fresh rock blocks obtained from 5 selected locations around Mt. Palgong are performed to verify the variation of physical and mechanical properties related to metamorphic grade of the rock. Water content and absorption ratio of the hornfels linearly increase with distance to the granite boundary whereas dry unit weight, p-wave velocity, point load strength, and slake durability index linearly decrease with the distance. These results imply that the metamorphic grade of the hornfels also linearly decrease with the distance to granite boundary. Empirical equations for the variation of properties with the distance to granite boundary and relationship between a property and another one are deduced by regression analyses. And a criteria for classification of hornfels exposed in the study area based on the P-wave velocity and point load strength is proposed.

• Journal of the Korean Chemical Society
• /
• v.56 no.2
• /
• pp.228-235
• /
• 2012

A $N_2O_2$ Schiff base ligand, N,N'-bis(4-methoxysalicylidene)phenylendiamine (4-$CH_3O$-salphen) was synthesized. Using the 4-$CH_3O$-salphen, the spectrophoto-metric quantitative analysis of Cu(II) ion in aqueous solution was performed. The optimum condition for the quantitative analysis of Cu(II) ion was determined as the following; the concentration of 4-$CH_3O$-salphen is $2.0{\times}10^{-4}\;mol/L$, ratio between solvent DMSO and water is 50/50(v/v), pH is 5.5. After 1 hr water incubation at $55^{\circ}C$ and then the absorbance measurements at 388 nm, a calibration curve (${\varepsilon}=3.6{\times}10^4\;mol^{-1}cm^{-1}$) with a correlation coefficient ($R^2$=0.9963) was obtained in this condition. Using this optimized condition, the quantitative analysis of Cu(II) ion was performed with various samples such as hot spring water, semiconductor factory waste water and treated water from sewage treatment plant. The average value of the measured values agreed well with standard value with a range of 0.6~5.4%. The limit of determination was 31.77 ng/mL ($5.0{\times}10^{-7}\;mol/L$).

• Journal of the Korean Geosynthetics Society
• /
• v.18 no.4
• /
• pp.115-127
• /
• 2019

The low-flow grouting injection technique, the target construction method for this study, is a method of pouring mortar into the ground by non-emission replacement principle, which can be expected to increase the density of the ground, and, in some cases, be used as a base file using the strength of the high injection solids, along with low noise, low pollution, and high durability. To verify that the dynamic characteristics of the ground are improved by the low-flow injection technique, the test work was conducted on the site and physical tests were performed, and the quality of the improvement formed in the ground was verified through the indoor test on the core and core recovery rate was analyzed. The density logs test layer calculated the volume density of the ground layer by using the Compton scattering of gamma-rays, and the sonic logs was tested on the ground around the drill hole using a detector consisting of sonar and receiver devices inside the drill hole. As a result of the measurement of the change in physical properties (density and sonic logs) before and after grouting, both properties were basically increased after infusion of grout agent. However, the variation in density increase was greater than the increase in speed after grouting, and the ground density measurement method was thought to be effective in measuring the fill effect of the filler. Strength and core recovery rates were measured from specimens taken after the age of 28 days, and the results of the test results of the diffusion and strength test of the improved products were verified to satisfy the design criteria, thereby satisfying the seismic performance reinforcement.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2017.04a
• /
• pp.8-8
• /
• 2017

본 연구는 로타리 작업에 따른 105마력급 농업용 트랙터의 소요동력을 분석하기 위하여 수행되었다. 소요동력 측정 시스템은 차축 토크미터, PTO 토크미터, 주/보조 유압센서, 데이터 수집장치를 이용하여 구성하였다. 시험에 사용된 트랙터는 동양물산 105 HP급 트랙터 (S07, TYM, Korea)이며, 작업기는 로타베이터 (SW 230GL, Sungwoo Industrial Co. Ltd, Korea)를 사용하였다. 포장시험은 전라북도 부안군에 죽림길에 위치한 $4,000m^2$ ($100m{\times}40m$) 크기의 경작지 2곳에서 수행하였다. 포장시험 시 작업 단수는 주행단수 L3단 (2.38 km/h)에서 PTO 단수 1단 (540 rpm)과 2단 (750 rpm)으로 설정하였고, 로타리 작업 시 경심은 13 cm 조건에서 실시하였다. 트랙터 작업은 동양물산의 성능시험 업무를 맡고 있는 숙련된 작업자가 숙달된 방법으로 수행하였다. 포장시험지의 토양환경은 임의의 15곳에서 채취한 시료를 이용하여 토성, 함수율, 원추 관입지수에 대하여 미국 농무부 (USDA)법을 기준으로 분석하였다. 토양환경 분석 결과 토성은 Sandy loam (사양토), 평균 함수율은 35.15%, 평균 원추관입지수는 1,562 kPa로 나타났다. PTO 1단 작업 시 트랙터의 평균 소요동력은 차축, PTO, 주 유압, 보조 유압에 대하여 각각 1.8, 54.0, 1.3, 그리고 1.1 hp로 나타났다. PTO 2단 작업 시 트랙터의 평균 소요동력은 차축, PTO, 주 유압, 보조 유압에 대하여 각각 1.2, 79.4, 1.2, 그리고 1.0 hp로 나타났다. PTO 1단 작업 시 소요동력의 합은 58.2 hp로, 정격 마력 (105 hp) 대비 55.43 % 사용한 것으로 나타났으며, PTO 2단 작업 시 소요동력의 합은 82.8 hp로, 정격 마력 대비 78.85% 사용한 것으로 나타났다. PTO 1단 대비 2단에서는 PTO를 제외한 차축, 주 유압, 보조 유압의 소요동력이 감소하였으나, PTO에서 약 1.47배로 크게 증가하여 전체적으로 소요동력이 증가한 것으로 나타났다. 향후 다양한 작업기 및 작업 단수에 따른 소요동력을 분석하여 농업용 트랙터의 모든 부하 조건에 대한 데이터베이스 구축에 관한 연구를 수행할 예정이다.

• The Journal of Engineering Geology
• /
• v.25 no.2
• /
• pp.189-199
• /
• 2015

Our country's leading granite weathered soil of the ground slope failures that occur in cutting slope most cases, it does not require in-depth to the shear strength most of the surface layer is affected by weathering (1~2 m) at a shallow depth close to the ground, it is important to identify the reliability. Based on the result obtained in actual field investigation, the field slope type was classified by each type of wedge slope, Infinite slope, finite slope -I and finite slope -II, and the slope stability was examined respectively. In addition, using the numerical analysis results, the relationship between the slope inclination angle and safety factor was analyzed and it tried to offer basic data to which the stability in the field slope was able to be estimated by analyzing the safety factor change of the slope according to the slope type. In this study, classified into four types of natural slope, safety factor estimation method by slope types is proposed through the numerical analysis. However, some limit exists in generalizing in this research because it does not test various case studies. Therefore, the case study of a wide range of various sypes to assess the safety of various types slope can be made, accommodate a wide range of field conditions reasonable risk evaluation criteria may be derived.

• The Journal of Engineering Geology
• /
• v.17 no.1 s.50
• /
• pp.125-133
• /
• 2007

The environmental and geotechnical properties are investigated to the 8th landfill area made of only sewage sludge in Nanji-Do. To do this, the soils are sampled in this area, and leaching tests, heavy metal content tests, and so on are performed to research the environmental properties. As the result of heavy metal content tests, Pb, Zn, Cu, Ni, Cd and Cr were leached from the sewage sludge. Because the leaching concentration of Cu is more than the standard value of California state, Cu content have to bring down during the recycling of the sewage sludge. Meanwhile, a series of tests concerning specific gravity, liquid and plastic limits, compaction, permeability and shear strength is performed to research the geotechnical properties. The sewage sludge is consisted of sand, silt and clay, and is classified into non-organic silt or organic clay with 42.3% of plastic index. As the result of compaction test, it is expected that the compaction effect according to variation of water contents is low relatively because the dry unit weight is low and the curve of compaction forms flatness. Also, as the result of direct shear tests, the cohesion is $0.058kg/cm^2$, and the internal friction angle is $14^{\circ}$. Taking everything into consideration, the various problems are happening in case of recycling the sludge like the cover layer of landfill and so on because the compaction is bad, and the shear strength is low. Also, it is expected that the ground water pollution caused by leaching the heavy metal into the sludge. To do recycling the sewage sludge in this site, supplementary and treatment programs should be prepared.

• The Korean Journal of Pesticide Science
• /
• v.18 no.4
• /
• pp.228-235
• /
• 2014

The residue levels of flonicamid and its metabolites, 4-(trifluoromethyl)nicotinic acid (TFNA) and N-4-(trifluoromethyl)nicotinoyl glycine (TFNG) in sweer pepper were investigated to examine the residual characteristics of analytes for 87 days after pesticide application. The pesticide was applied once at recommended dosage and double dosage by foliar sprays and the samples of fruits and leaves of sweet pepper were collected for each treatment. The residues of flonicamid in all of fruits and leaves decreased gradually over time, while the residue levels of TFNG metabolite exhibited tendency that increased for long periods and thereafter decreased. Total flonicamid residual concentrations containing metabolites residues in fruit samples increased consistently until 30 days post-application and higher residue levels than residues at 1 day post-application were detected from 30 day to 87 day after treatment. The residue pattern observed in fruit could be explained by the movement of TFNG from leaves to fruits of plant. Such residual characteristic was similarly found in samples treated both recommended dosage and double dosage.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.24 no.4
• /
• pp.69-76
• /
• 2016

To produce the primary data for best management of soil nutrient in organically practiced soils, 75 leading organic farms whose paddy fields were certified as organic were selected. Soil samples were collected from the paddy fields before plowing, and then analyzed for the determination of physico-chemical properties. Soil pH, organic matter and available phosphate were analyzed and averaged 6.2, $25.6mg\;kg^{-1}$ and $88.4mg\;kg^{-1}$, respectively. Contrary to the national-scale-surveyed paddy soils including organic and conventional farming, pH was higher, available phosphate was lower in the organically practiced soils, but organic matter was similar. With the increasing cultivation period in organic, soil pH and porosity were also increased, EC, available phosphate, bulk density and soil hardness were lower than those from the national survey. Organic matter, however, was not significantly changed. The bulk density was negatively correlated with the organic matter content for both surface topsoil ($R^2=-0.5424$) and subsoil ($R^2=-0.6429$) (p<0.05). Soil quality is improved in most of soil chemical and physical composition factors excluding organic matter and available phosphate. However, it is necessary to establish the counter measure plan for organic matter management and to develop phosphate-containing materials which can be used as organic agricultural material in the future.

• The Korean Journal of Pesticide Science
• /
• v.21 no.1
• /
• pp.17-25
• /
• 2017

Dissipation pattern and biological half-lives of fungicides boscalid and pyraclostrobin were calculated on jujube. The pesticides were sprayed on jujube in two different field at the standard rate, respectively. The raw agricultural commodities were harvested at 0 (2 hr), 1, 3, 5, 7, 10 and 14 days after treatment, and analyzed by HPLC/DAD. The method limit of quantification (MLOQ) was $0.02mg\;kg^{-1}$ for boscalid and pyraclostrobin. The recovery ranged 101.8~109.3% with below 5% of CV (Coefficient of variation) for boscalid and 104.2~115.4% with below 5% of CV for pyraclostrobin. An average initial deposit at field 1 and field 2 samples were observed 0.40 and $0.48mg\;kg^{-1}$ for boscalid and, 0.76 and $0.57mg\;kg^{-1}$ for pyraclostrobin, respectively. The biological half-lives of field 1 and field 2 were 11.0 and 13.2 day for boscalid, and 6.1 and 12.7 days for pyraclostrobin.