• Journal of Environmental Impact Assessment
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• v.29 no.4
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• pp.252-271
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• 2020

In this study, we investigated physical and chemical properties such as grain size, heavy metal pollution, magnetic properties, and their environmental impacts of road dusts (RD) collected from 14 sampling points in Daebul industrial Complex. Heavy metal concentrations in RD were in the order of Fe>Zn>Cu>Pb>Cr>Ni>As>Cd>Hg, and this pollution pattern was related to major industries and traffic activities in this area. The results of the correlation analysis between heavy metal elements and particle size in RD showed that Fe and all of analyzed heavy metals had a significant correlation with each other and metal concentrations had a significantly negative correlation (p<0.05). However, due to the input of large metal particles some heavy metal concentrations in the particle fraction of >1000 ㎛ were highest. Pollution load per unit area of this fraction was the highest among the grain size fractions. Cr, Ni, Cu, Zn, Cd, Pb levels in RD decreased and the levels of Cr, Ni, Cu, Zn, Cd, and Pb were reduced to 85 (As) -22 (Ni)% of the whole after removal of MFs fraction from RD. The mean heavy metal levels in the study area did not exceed the soil contamination guide value of Korea, indicating that heavy metal levels in RD were not a concern. However, at some sampling points, Zn concentrations were exceeded the soil contamination guide value for the 3rd areas of Korea and this result indicated that further studies of the impact of RD on the surrounding environment through re-suspension or non-point pollution, and of effective management methods are required.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1531-1531
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• 2001

A novel technique has been developed to observe the three-dimensional (3-D) distribution of chemical components in biological materials using both automatic sectioning microtome and infrared microscope. The 3-D image was reconstructed based on the relationship between the content and the absorbancy of specified wavelength for chemical components. By using the automatic sectioning microtome, the kernel of rice sample fixed in paraffin was sequentially sliced with the thickness of $5\;\mutextrm{m}$ after pasting the sliced sectional specimens on an adhesive tape. The chemical components of the specimens, which are placed on the X-Y controlling stage with positioning accuracy of ${\pm}10\;\mutextrm{m}$, were analyzed by the infrared microscope. The 3-D images demonstrated that the zonal protein about $200\mutextrm{m}$ in width was observed mainly at the outer parts of a rice particle, and carbohydrates entirely. These images can be observed by choosing arbitrary observation angle. The result indicated that the developed technique could be applied 3-D information to investigate intrinsic chemical components but also residual pesticides as well as bacteria contamination for agricultural produce.

• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.58-66
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• 2005

Pseudo-Near Field Recording (Pseudo-NFR) system is proposed to prevent contamination and oxidation of media surface occurred in conventional NFR systems. To solve these critical problems of the NFR systems, we investigate the optimal thickness of cover layer for Pseudo NFR. This paper presents the theoretical analysis for cover layer thickness based on the measured length of dust particle and numerical simulation for the temperature distribution using Finite Difference Time Domain (FDTD) method and heat conduction equation. To verify the simulation results, we conduct and compare simulation results in case of far field MO recording and near field MO recording. A measured dust particle length in general environment was mostly less than $20{\mu}m$, and the optimal thickness of cover layer is $30{\mu}m$ in this case. Based on the designed optimal cover layer thickness, temperature distribution is simulated to have $800{\~}850^{\circ}C$.

• Journal of ILASS-Korea
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• v.10 no.2
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• pp.10-17
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• 2005

The proposed research has been performed to know the characteristics of cutting fluid aerosol formation using Dual-PDA system in machining process. The cutting fluid aerosol size and concentration is common attributes that quantify the environmental intrusiveness or air quality contamination. The atomized cutting fluid aerosols can be affected to human health risk such as lung cancer and skin irritations. Even though cutting fluid can be improved the machining quality and productivity in a carefully. its use must be controlled and optimized carefully. This experimental works using Dual-PDA were performed to analyze the cutting fluid aerosol behaviors and characteristics in turning process using precise aerosol particle measuring system. The obtained experimental results profovide basic knowledge to develop the environmentally conscious machining process. This results cail be provided as a basis to estimate and control the hazardous cutting fluid aerosol in machining process.

• Journal of Soil and Groundwater Environment
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• v.16 no.1
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• pp.71-81
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• 2011

Cause of contamination in the study area nearby Jang Hang Refinery is dust scattering in refinery stack, and soil washing treatment is one of the proper technologies for soil remediation in this area. Site conditions frequently limit the selection of a treatment process. A treatment technology may be eliminated based on the soil classification or physicochemical characteristics of soil. This study was assessed the soil washing efficiency by conducting of soil characteristic analysis in the vicinity of Jang Hang Refinery Stack within a 2 km radius. Also, it was decided about remedial range with comparative analysis of As in soil by Korean Standard Test Method before/after revision, whereupon As concentration in soil showed a increasing tendency after revision. As a result, the soil washing using the size separation of soil was determined through identifying of As species in the soil. In this site, only particle size distribution and water content of soil can provide the initial means of screening for the potential use of soil washing.

• Particle and aerosol research
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• v.15 no.1
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• pp.27-36
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• 2019

Numerical analysis has been conducted on three-dimensional airflow distribution in the passenger cabin of a high-speed electric train. The types of air distribution systems investigated in the present study were those of TGV and Shinkansen. The Reynolds-averaged Navier-Stokes equations governing the mass and momentum conservations of the airflow in the cabin were solved by using a finite volume method, which are coupled with the standard $k-{\varepsilon}$ turbulence model equations. Predicted velocity distributions were presented on several selected planes in the passenger cabin. The present three-dimensional simulations were found to show the overall features of the airflow in the passenger cabin fairly well. In particular, it was shown that the type of air distribution for Shinkansen was more suitable for a non-smoking cabin than that for TGV.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.5 no.3
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• pp.169-177
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• 1976

The importance of surface conditions of nucleate boiling is well recognized and it has been known that the heat transfer to boiling liquid is closely related to the bubble population density. The bubble population density should depend on various factors such as heat flux, surface roughness, surface contamination, properties of liquid, etc. In this paper the effect of surface conditions on heat transfer in nucleate boiling is treated. The experiments were carried out with distilled water boiler, on the horizontal heating surfaces, sintered with various bronze particle, under atmospheric pressure. In addition, experimental investigation for the polished bronze surface was performed. By studing a coefficient Xb defined by eq. (9), which represents the bubble foaming ability of heating surface, generalized fomula on the heat transfer in the nucleate toiling were expressed. The coefficient $X_b$, determined empirically, is not constant and indicates a major influence of the sintered metal surfaces on the $\Delta$, necessary to sustain nucleate boiling at any given heat flux. In this study, the main results are obtained as follows; (1) At low temperature difference, the coefficient $X_b$ of sintered metal surface was found to he higher than the polished surface throughout the full range of experiments. (2) The optimum sintered structure showing the maximum coefficient $X_b$ has been confirmed to exist and it is encountered when particle diameter is $256{\mu}$.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.5
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• pp.277-284
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• 2015

In order to analyze the contamination level of sediment samples taken from Chusori and Chudong areas in Daechung Reservoir, the particle size and concentrations of organics and nutrients were analyzed and phosphorus fractionation analysis was conducted. The average fraction of silt-sized particles was 92% in the sediments taken from Chudong area and Chusori area at the site adjacent to main current, which was higher than that from the upper Chusori area. The concentrations of total phosphorus in the sediments at Chusori and Chudong area were 999 (${\pm}98$) and 1,123 (${\pm}119$) mg/kg sediment, respectively. The fractions of autochthonous phosphorus, which can be readily eluted by change of environmental conditions, were much higher than those of allochthonous phosphorus, indicating the internal load can contribute the eutrophication in these areas. The concentrations of total nitrogen were over 5,600 mg/kg sediment in all samples, which is the guideline of Contamination Assessment of River and Lake Sediments of the Ministry of Environment, indicating the contamination level of total nitrogen is serious in the sediments. It is concluded that the countermeasures to manage the quality of sediments are required to improve the water quality in the Daechung Reservoir.

• Journal of Mechanical Science and Technology
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• v.20 no.12
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• pp.2025-2033
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• 2006

This paper presents, the design of a latch mechanism for wafer containers in a standard mechanical interface environment. For an integrated circuits fabrication factory, the standard mechanical interfaced wafer container is an effective tool to prevent wafers from particle contamination during wafer storage, transporting or transferring. The latch mechanism inside the container door is used to latch and further seal the wafer container for safety and air quality. Kinematic characteristics of the mechanism are established by analyzing the required functions of the mechanisms. Based on these characteristics, a methodology for enumerating feasible latch mechanisms is developed. New mechanisms with one degree-of-freedom and up to five links are generated. An optimum design is also identified with respect to the criteria pertinent to the application. The computer-aided simulation is also built to verify the design.

• Korean Journal of Poultry Science
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• v.26 no.2
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• pp.85-95
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• 1999

The mechanically deboned chicken meat(MDCM) has several limits in using for in using for in processed meat products as a main material because of poor color and textural properties, chance of microbial contamination and lipid oxidation. There has been a growing interest all over world in the application of MDCM to the surimi process. The surimi made from MDCM contains a high concentration of myofibrillar protein since this processing involves repeated washing processes with an aqueous solution in order to remove heme pigments, fat and other undesirable substances. The quality of the surimi made from MDCM is affected by various processing factors, such as kinds of wash solution, ion strength, washing cycle, temperature, pH changes, composition, part of muscle, particle size, and rigor state etc. A number of researchers havee investigated the effect of the various washing conditions on the properties of surimi gels. A fuller information of all the factors affecting surimi processing and gel formation by heat-induced gelation has not been known yet.