• Korean Journal of Medicinal Crop Science
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• v.11 no.5
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• pp.364-370
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• 2003

Essential oil of Thuja occidental leaves was extracted by steam distillation method, and chemical composition of essential oil was analyzed by GC-MS. The essential oil was tested to antimicrorbiaI activity against 28 test microorganisms and antioxident assay through DPPH free radical scaveging test and insecticidal activity by mosquito insecticide assay. The major constituents in the essential oil of T. occidental were monoterpene as d-isothujone, ${\alpha}-thujone$, camphor, L-fenchone, and hornyl acetate. The essential oil have broad antimicrobiaI activity, which showed strong antimicrobiaI activity for Streptococcus pyogenes as bacteria, Alternaria alternata, Aspergillus niger, Aspergillus oryzae, Saccharomyces cerevisiae, and Streptococcus mutans as fungi. The essential oil also showed DPPH free radical scavenging ability at concentration of $36\;{\mu}{\ell}/m{\ell}$. In spraying and fumigation tests, the essential oil had strong insecticidal activity against mosquito.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.479-483
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• 2014

The area of greenhouse horticulture has increased dramatically since the early 1990s in Korea. However, area per farmer still very small and diverse pest species occurs in greenhouse abundantly because of its protected condition. To manage pests, farmers use many pesticides frequently. Incessant and improper use of chemicals provoked pesticide resistance in pest and poisoning of farmers. In this study, we investigated the efficiencies of automatic dry fog sprayer for controlling two aphid species, Aphis gossypii and Myzus persicae, in greenhouse horticulture. When doors and side windows were completely closed in automatic dry fog sprayer treatment greenhouse, aphids were controlled similar level with conventional spraying method (percent control: 61.0~94.1%). However, when half of the doors and side windows of the greenhouse were opened, aphids were controlled poorly (percent control: 36.0~54.4%).

• Journal of Environmental Impact Assessment
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• v.22 no.6
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• pp.547-556
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• 2013

Recently, golf courses have increased over the years because golf became popular leisure sport. Various environmental problems have been then issued by a golf course during constructing and running them. A problem of pesticide, which is serious among various environmental problems, from golf course has harmful effect on surrounding area and makes human suffer from acute and chronic diseases. Pesticides are used for the cost-effective managing of golf course and the amount of pesticides also increases as the number of golf course increase. Since the assessment of pesticides on near-by surrounding has been focused on water and soil media, studies related to atmospheric dispersion have been hardly attempted. The method to assess an impact of pesticide nearby agricultural production by the atmospheric dispersion using AGDISP(AGricultural DISPersal) model was developed and applied to the actual planned golf course located in Hongcheon, Gangwon. For implementing AGDISP, parameters were investigated from the golf course's land use planning map, pesticide spray device, Hong-Cheon weather station and etc. First of all, a kind of pesticide, a form of spraying pesticide, geographical features, weather data, and distance(golf course to plantation) were investigated to understand how to work these parameters in AGDISP. Restricted data(slope angle, droplet size distribution and solar insolation) sensitivity analysis of these parameters to estimate effect of pesticide nearby a plantation and a high relative contribution data of analyzed data was selected for input data. Ethoprophos was chosen as the pesticide used in the golf course and the amounts of pesticide deposition per annual agricultural productions were predicted. The results show that maximum amount of pesticide deposition through atmospheric dispersion was predicted $2.32{\mu}/m^2$ at 96 m where the nearest organic plantation exists. The residues of pesticide were also estimated based on the annul production of the organic and the deposition amount of the pesticide. Consequently, buckwheat, wheat and millet were likely to exceed maximum residue limits for pesticides in foods(MRL) and sorghum, corn and peanut were likely to exceed MRL by organic farming as well.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.37-47
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• 2004

In Korea, over three hundreds of the coal mines were closed or abandoned due to the depression of the mining industry since the late 1980s. Many of them locate in the steep mountain valleys and the coal mine wastes had been disposed without a proper treatment From these mines, enormous amounts of coal mine overburdens have been abandoned in the slopes and the ample amounts of acid mine drainage (AMD) from either portal or overburdens have been discharging directly to the streams, causing the detrimental effects on soil and water qualities. Objectives of this research were to reclaim the coal mine overburdens using the lime waste cake from the soda ash production by stabilizing the overburden slopes, introducing the vegetation alleviate the environmental problems caused by the closed coal mines. The percentages of the grass distribution ratio (%) and the surface coverage ($\textrm{cm}^2$) in each treatment plot were determined during June to August after seed spraying grasses such as orchard grass (Dactylis glomerata L), Kentucky Bluegrass (Poa pratensis L.) and Eulalia (Miscanthus sinensis Anderss) at the end of May. The grasses covered only 15.5 % of the coal overburden plot at the early stage but the coverage was increased with time to 33% in August. Growth of such grasses was enhanced with the combined treatments of lime waste and topsoil resulting in the increased surface coverage by the grasses. The Increment of the surface coverage from June to August was higher with lime waste treatments. The distribution percentages and surface coverage were highest when the lime wastes were treated at 25 % of the lime requirement. This might be related with the high salt contents in the hire wastes. Results demonstrated that the amounts of lime wastes at 25% of the lime requirement were sufficient for neutralizing the acidic coal overburden and introducing the re-vegetation. Either layering between the coal waste and topsoil or mixing with coal overburdens could be adopted as the lime waste treatment method. The combined treatment of lime wastes and topsoil was recommended for re-vegetation in the coal overburden slopes. The lime wastes from the soda ash production might have a potential to be recycled for the reclamation of the abandoned coal mines to alleviate the environmental problems associated with coal mine waste.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.10
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• pp.206-211
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• 2020

Tungsten alloys are used widely in general industrial fields, but they are difficult to cast, so products are manufactured using powder metallurgy. In this study, a mixed powder of tungsten, nickel, and iron homogenized using a ball mill was added to pure water as a solvent, and PVA as a binder was added to prepare a spray drying mixture. The mixed liquid was prepared using a spraying machine. A study was carried out to produce a granular powder that can reduce the variations between products during the molding and sintering process of the powder metallurgy method. A preliminary experiment was conducted to confirm the influence of the variables in the granulation process. Through the preliminary test results, this experiment was performed with the volume of solvent of the spray drying the mixture as an independent variable, and granular powder having a mean particle size similar to that of the existing mass-production conditions and an increased apparent density was prepared. In addition, a pilot test was conducted for the molding and sintering process. The improved granular powder reduced the characteristic variation (weight variation) of the mass-produced product.

• Journal of Korean Society of Forest Science
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• v.85 no.4
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• pp.619-633
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• 1996

This study was carried out from March 1995 to February 1996 to select suitable vegetation and measures for revegetation on the highway cut-slope in consideration of the surrounding environment in the middle region of Korea. The numbers of revegetation-measures type surveyed were eighteen measures as a whole in descending order of the Seed-spraying measures, Block-sod pitching measures, and Straw-mat mulching measures. The numbers of vegetation species by highway line were 243 in Chungbu, 223 in Jungang, 210 in Kyongbu 2, 199 in Kyongbu 1, 179 in Sohaean, 163 in Seoul circulation. 148 in Shingal-ansan, 141 in Second kyongin and 123 in Kyongin respectively. The highest index of species diversity(H') was in Kyongbu 1-line and the evenness(E') on upper site was greater than that of the lower site. The revegetation measures were selected in consideration of nature of soil, gradient, area and situation, and 83 species were selected as those for revegetation measures in highway cut-slope.

• Resources Recycling
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• v.9 no.4
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• pp.28-36
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• 2000

This study describes to analyze the characteristics for separation and recovery of both the dried particles and the purified solvent from the waste solvent through the vaporization process by the continuous and instantaneous vacuum drying system. The vacuum drying system for the waste solvents recovery consists of a feeding pump, a double pipe heat exchanger, a vacuum spray chamber, and a condenser. The vacuum drying system heats the waste solvent to the vapor in the double pipe heat exchanger and the expanded vapor is sprayed at the end of the tube. The vaporized solvent in the condenser are recovered. The particles in the waste solvent are separated and dried from the vapor in the vacuum spray chamber. Performance evaluation of the vacuum drying system was conducted using the mixture of the dried pigment particles and benzene or alkylbenzene as test samples. For the mixture of 10 wt% pigment particles an 90% benzene, the recovery efficiency of benzene was 88% with the purity of 99% and the recovery efficiency of dried particles was 94% with the moisture of 1.1 wt%. The size of pigment particles was decreased from $6.5\mu\textrm{m}$ to $5.6\mu\textrm{m}$ in diameter due to high speed spraying and dispersion in the vacuum drying system during drying process. Therefore, the vacuum drying system showed to be an effective method for separating particles and solvent in the waste solvent.

• Composites Research
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• v.33 no.6
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• pp.360-364
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• 2020

Although research and development of existing steel-made Cowl Cross Member(CCM) was carried out with magnesium and plastic to make vehicles lighter, it is difficult to apply them to performance problems in the vehicle's mounting condition. Recently, the company is conducting research on the injection CCM of the composite insert as a lightweight component that is most suitable for mass-production of automotive parts. This is a manufacturing process that inserts composite injection bracket parts into aluminum bar, and the adhesion of the two parts is one of the important factors considering the vehicle's mounting conditions. In this study, the joint strength of Aluminum bar is one of the important factors as a study for the injection of aluminum bar into PA6-GF60 composite material. For the analysis of these research, the method of spraying adhesive to the aluminum bar and the case of knurling treatment have been analyzed and the bonding strength of the direction of rotation and lateral direction has been analyzed for each part between the aluminum bar of the cowl cross member and the shape of the injection component of composite materials.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.177-184
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• 2021

While veterinary antibiotics are used only in a part of the dose administered, the rest are excreted as urine or feces. Residual antibiotics enter the adjacent agricultural environments by spraying manure-based composts on farmlands and lead to secondary pollution. Therefore, it is necessary to develop the technique for post management such as regulatory levels of antibiotics in the agricultural environments. This study was conducted to compare by different matrices the amount of residual antibiotics such as tetracyclines and sulfonamides, which are known to be frequently used in Korea and to practice risk assessment by different antibiotics in soils before and after application of composts. Pre-treatment with modified typical method using buffer and solid phase extraction showed the recovery of composts and soils was more than 70% at ppb level and the limits of detection were 0.13-0.46 and 0.05-0.25 ㎍/kg, respectively. Analysis of manure-based composts revealed concentrations from 5.38 to 196.0 ㎍/kg for tetracyclines, from below the detection of limit (BDL) to 259.0 ㎍/kg for sulfonamides. In case of agricultural soils, residual concentrations of selected veterinary antibiotics were ranged 0.30-53.3 ㎍/kg, BDL-4.16 ㎍/kg respectively and the concentration level of tetracyclines, which had higher soil distribution coefficient (Kd) values, was higher than that of sulfonamides. There was a difference in human risk assessment by different antibiotics in soil before and after application of composts. But, it was indicated that detection values of all of 5 antibiotics were very safe on the basis that Hazard Quotient was safe below 1.

• Journal of Internet of Things and Convergence
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• v.8 no.2
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• pp.35-40
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• 2022

In the agricultural environment, pesticide control requires a high risk of work and a high labor force for farmers. The effectiveness of pesticide control using unmanned aerial vehicles varies according to climate, land type, and characteristics of unmanned aerial vehicles. Therefore, an effective method for pesticide control by unmanned aerial vehicles considering the spraying conditions and environmental conditions is required. In this paper, we propose an efficient pesticide control system based on agricultural unmanned aerial vehicles considering the application conditions and environmental information for each crop. The effectiveness of the proposed model was demonstrated by measuring the drop uniformity of pesticides according to the change in altitude and speed after attaching the sensory paper and measuring the penetration rate of the drug inside the canopy according to the change in crop growth conditions. Experiment result, the closer the height of the UAV is to the ground, the more evenly the crops are sprayed, but for safety reasons, 2m more is suitable, and on average a speed of 2m/s is most suitable for control. The proposed control system is expected to help develop intelligent services based on the use of various unmanned aerial vehicles in agricultural environments.