• Journal of Korean Neurosurgical Society
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• v.62 no.4
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• pp.414-421
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• 2019

Objective : To evaluate 3-dimensional magnetic resonance imaging (MRI) of Kambin's safe zone to calculate maximum cannula diameter permissible for safe percutaneous endoscopic lumbar discectomy. Methods : Fifty 3D MRIs of 19 males and 31 females (mean, 47 years) were analysed. Oblique, axial and sagittal views were used for image analysis. Three authors calculated the inscribed circle (cannula diameter) individually, within the neural (original) and bony Kambin's triangle in oblique views, disc heights on sagittal views and root to facet distances at upper and lower end plate levels on axial views and their averages were taken. Results : The mean root to facet distances at upper end plate level measured on axial sections increased from $3.42{\pm}3.01mm$ at L12 level to $4.57{\pm}2.49mm$ at L5S1 level. The mean root to facet distances at lower end plate level measured on axial sections also increased from $6.07{\pm}1.13mm$ at L12 level to $12.9{\pm}2.83mm$ at L5S1 level. Mean maximum cannula diameter permissible through the neural Kambin's triangle increased from $5.67{\pm}1.38mm$ at L12 level to $9.7{\pm}3.82mm$ at L5S1 level. The mean maximum cannula diameter permissible through the bony Kambin's triangle also increased from $4.03{\pm}1.08mm$ at L12 level to $6.11{\pm}1mm$ at L5S1 level. Only 2% of the 427 bony Kambin's triangles could accommodate a cannula diameter of 8mm. The base of the bony Kambin's triangle taken in oblique view (3D MRI) was significantly higher than the root to facet distance at lower end plate level taken in axial view. Conclusion : The largest mean diameter of endoscopic cannula passable through "bony" Kambin's triangle was distinctively smaller than the largest mean diameter of endoscopic cannula passable through "neural" Kambin's triangle at all levels. Although proximity of exiting root to the facet joint is always taken into consideration before PELD procedure, our 3D MRI based anatomical study is the first to provide actual maximum cannula dimensions permissible in this region.

• Korean Journal of Environmental Agriculture
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• v.32 no.4
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• pp.273-278
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• 2013

BACKGROUND: Total petroleum hydrocarbons (TPH), which are main materials of soil contamination by oil, are a term used for any mixture of hydrocarbons. Korea Ministry of Environment established the maximum permissible level of TPH in farmland by 500 mg/kg, and reported that the TPH level of soil in 266 installation such as gas station, transport company, and military unit ranged from 1,356 to 55,117 mg/kg and were much higher than the maximum permissible level in 2011. METHODS AND RESULTS: To determine the effect of TPH on crops, we investigated the effect of gasoline, kerosene, and diesel on the germination and radicle growth of mainly consumed crops. The germination rates of control in investigated all crops ranged from 80.0-100%. The germination and radicle growth in majority of investigated crops were not inhibited even at 2,500 mg/L. However, germination in onion, leek, and green perilla and radicle growth in leek, rape, tomato, and green perilla were significantly inhibited by increasing concentrations of gasoline, kerosene and diesel treatment. Germination and radicle growth inhibition of green perilla by kerosene and diesel were the highest, the percent inhibition at the 500 mg/L were 100 and 98.6%, 100 and 88.2%, respectively. 50% inhibition of germination in green perilla by kerosene and diesel were 39.96 and 29.87 mg/L, and 50% inhibition of radicle growth were 52.76 and 177.96 mg/L, respectively. Conclusion(s): These results suggest the possibility that the maximum permissible level of TPH might to be established general level with exception by crops.

• Journal of environmental and Sanitary engineering
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• v.9 no.2
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• pp.110-119
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• 1994

The objective of the this study was to evaluate the effects of heavy metals on the sewage treatment process designed to remove organic material and nutrients using Water- hyacinth ( Eichhornia crassipes ). Batch experiments were carried out using domestic sewage spiked with different level of heavy metal mixtures ( Cd, Pb and Cu ). The specific growth rates of Water- hyacinth ranged from 0.0008 to 0.0015 1/day( operated at water temperatures of 22 ∼30$\circ $c ) and increased as the concentration of heavy metals decreased. The test result showed that the permissible maximum concentrations Cd, Pb and Cu for the growth of Water- hyacinth were 0.5, 1, and 6 mg/ℓ respectively. Under these maximum permissible heavy metal loads, removal rate of organic material, nitrogen and phosphorus were 85%,75% and 75% , respectively, during 40days of the test period.

• Structural Engineering and Mechanics
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• v.33 no.4
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• pp.529-537
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• 2009

A key parameter in the design of a laterally loaded pile is the determination of its performance level. Performance level of a pile is usually expressed as the maximum head deflection and bending moment. In general, uncertainties in the performance of a pile originates from many factors such as inherent variability of soil properties, inadequate soil exploration programs, errors taking place in the determination of soil parameters, limited calculation models as well as uncertainties in loads. This makes it difficult for practicing engineers to decide for the reliability of laterally loaded piles both in cohesive and cohesionless soils. In this paper, limit state functions and consequent performance functions are obtained for single concrete piles to predict the maximum bending moment, a widely accepted design criterion along with the permissible pile head displacement. Analyses were made utilizing three dimensional finite element method and soil-structure-interaction (SSI) effects were accounted for.

• Korean Journal of Medicinal Crop Science
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• v.28 no.6
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• pp.435-444
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• 2020

Background: As the Positive List System (PLS) is implemented in broad application to agricultural products, attention to the correct use of pesticides is also needed in the production of mulberry leaves and fruit. In this regard, three types of pesticides against mulberry popcorn disease were applied 2 - 3 times both in the field and greenhouses to prepare safety standards. Residual pesticide analysis was conducted on mulberry fruits and leaves. Methods and results: Three pesticieds, thiophanate-methyl, thiophanate-methyl·triflumizole and fluopyram registered as PLS pesticides for mulberry popcorn disease, were sprayed in the Wanju and in Buan regions, after which residual pesticide analysis was conducted using high-performance liquid chromatography (HPLC). As three pesticieds were either undetected or below the permissible level in mulberry fruit, demonstrating that they were suitable for safe spraying. However, 5.6 mg/kg of thiophanate-methyl was detected in the greenhouse after three application, which was slightly above maximum residue limit (MRL). Furthermore the level of thiophanate-methyl·triflumizole was higher than 0.2 mg/kg ("Gwasang No. 2" variety, spraying twice) or similar to 0.09 mg/kg ("Daesim" variety, spraying thrice) the permissible level (0.1T mg/kg) as the thiophanate-methyl was detected in mulberry leaves in the greenhouse. Conclusions: The spraying frequency for controlling mulberry popcorn disease in greenhouses should be limited to two times or less, especially when mulberry leaves are treated with thiophanate-methyl·triflumizole careful consideration is required if the leaves are to be used as food materials.

• 전기의세계
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• v.25 no.6
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• pp.65-68
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• 1976

For the RIV characteristics test of power apparatus, an indoor measuring system of radio influence voltage was set up and by means of this measuring unit SIV characteristics on the 7$^{1}$2/" pin-type domestic insulators were examined. According to the test data, RIV values of all the test pieces exceeded the maximum permissible level at 10kV applied voltage. The electrical resistivity of domestic semi-conductive glaze as good as importedone but un-uniformity of coating is turned out to be a main cause of failure.lure.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.544-547
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• 2003

The objective of this study is to investigate the contamination levels and dispersion patterns of arsenic and heavy metals and to estimate the bioaccessible fraction of the metals in soil and plant samples in the vicinity of the abandoned Songcheon Au-Ag mine. Tailings, soils, plants (Chinese cabbage, red pepper, soybean, radish, sesame leaves, green onion, lettuce, potato leaves, angelica and groundsel) and waters were collected around the mine site. After appropriate preparation, all samples were analyzed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Elevated levels of As and heavy metals were found in tailings. Mean concentrations of As in agricultural soils were higher than the permissible level. Especially, maximum level of As in farmland soil was 513 mg/kg. The highest concentrations of As and Zn were found in Chinese cabbage (6.7 mg/kg and 359 mg/kg, respectively). Concentrations of As, Cd, and Zn in most stream waters which are used for drinking water around this mine area were higher than the permissible levels regulated in Korea. Maximum levels of As, Cd and Zn in stream waters were 0.78 mg/L, 0.19 mg/L and 5.4 mg/L, respectively. These results indicate that mine tailings can be the main contamination sources of As and heavy metals in the soil-water system in the mine area. The average of estimated bioaccessible fraction of As in farmland soils were $3.7\%$ (in simulated stomach) and $10.8\%$ (in simulated small intestine). The highest value of bioaccessible fraction of metal in farmland soils was $46.5\%$ for Cd.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.3
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• pp.70-76
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• 2007

The benefits for using reduced takeoff thrust are many, ranging from lower maintenance and operating costs to improved engine and dispatch reliabilities. Some pilots, however, are apprehensive about using reduced thrust. They are particularly reluctant to use the maximum permissible level of reduced thrust. Two common arguments are (1)If reduced thrust is used, then the airplane will not be able to clear the obstacles if an engine fails during takeoff, and (2)If the maximum allowable assumed temperature is used, then there will be no stopping margin left if the takeoff is aborted. There is the notion that using reduced thrust sacrifices safety. The intent of this discussion is to: (1)Show that reduced thrust performance meets all regulatory requirements (2)Show that the Assumed Temperature method includes inherent extra performance margins (3)Show how to maximize performance margins while maximizing thrust reduction.

• The Journal of Korean Society for Radiation Therapy
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• v.2 no.1
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• pp.31-40
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• 1987

In the case of designing a high dose rate remote controlled afterloading treatment room with existing hospital facilities. We must construct the effective protective barriers so as to reduce the primary and scattered radiation up to the maximum permissible dose level. It is difficult to reinforce the barrier thickness of the shielding requirements because of the limited space and the problem of the existing building structure at the surrounding area. Therefore we can reduce the intensity of primary radiation to the required degree at the location of interest with installing the appropriate I shaped Pb barriers between the radiation source and the shielding wall of the concrete. As a result, it was possible to reduce the intensity of the primary radiation below the M.P.D level by using additional Pb barriers instead of increasing thickness of concrete wall.

• Journal of Environmental Science International
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• v.19 no.6
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• pp.671-680
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• 2010

The present study evaluated residential exposure to atmospheric formaldehyde and acetaldehyde according to distance from the a dyeing industry complex (DIC). This purpose was achieved by measuring concurrently the outdoor air concentrations in residences near the DIC and a certain distance away, plus the outdoor air concentrations at two industrial areas within the DIC boundary. Formaldehyde concentrations (median values of 24.3 and $22.5{mu}g/m^3$ in IS1 and IS2, respectively) were higher than acetaldehyde concentrations (median values of 7.4 and $7.3{mu}g/m^3$ in IS1 and IS2, respectively) at both sites. However, there was no significant difference in the industrial outdoor air concentrations of both formaldehyde and acetaldehyde between the two sites. In addition, the median formaldehyde concentration from the residential site near the DIC (RS1) was about 1.5 times higher than that from the residential site far away from the DIC(RS2), and the median acetaldehyde concentration from RS1 was about 1.3 times higher than that from RS2. It is noteworthy that the mean or median risk as well as these maximum risks are well above the USEPA's permissible risk level of $10^{-6}$ from environmental exposure. This suggests that appropriate management for formaldehyde and acetaldehyde is necessary in order to decrease risk of the residents of study areas, regardless of the distance from the DIC.