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Environmental Health Strategies in Korea (우리 나라의 환경정책 방향)

  • 조병극
    • Journal of environmental and Sanitary engineering
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    • v.7 no.2
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    • pp.1-10
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    • 1992
  • Since 1960's along with industrialization and urbanization, economic growth has been . achieved, however, at the same time, environmental condition has been seriously deteriorated. . Currently, volume of wastewater has been increasing at annual rate of 7% in sewage and 20% in industrial wastewater. However, the nation's sewage treatment serves only 33% of the municipal wastewater as of 1991. Major portion of air pollutants comes from combustion of oil and coal which comprise 81% of total energy use and emission gases from motor vehicles increasing at an accelerated rate. It is known that Korea generates the highest amount of waste per capta. Nevertheless, it is not sufficient to reduce the volume of waste by means of resources recovery and recycling. Recognizing the importance of global environmental problems such as ozone layer depletion, global warming and acid rain, international society has been making various efforts since the 1972 Stockholm conference. In particular, it is expected that the Rio conference which has adopted the Rio declaration and Agenda 21 will form a crucial turning point of the emerging new world order after the Cold War confrontation. To cope with such issues as domestic pollution and global environmental problems, the fundamental national policy aims at harmonizing "environmental protection and sustainable development". The Ministry of Environment has recently set up a mid-term comprehensive plan which includes annual targets for environmental protection. According to the government plan, gradual improvement of various environmental conditions and specific measures to achieve them is planned in time frame. Additional sewage treatment plants will be constructed in urban areas with the target to treat 65% of the nation's municipal sewage by 1996. Supply of clean fuels such as LNG will also be expanded starting from large cities as a cleaner substitute energy for coal and oil. In parallel with expansion of LNG, emphasis will be placed on installation of stack monitoring system. Due to the relatively limited land, government's basic policy for solid waste treatment is to develop large scale landfill facilities rather than small sized ones. Thirty three regional areas have been designated for the purpose of waste management. For each of these regions, big scale landfill site is going to be developed. To increase the rate of waste recycling the government is planning to reinforce separate collection system and to provide industries with economic incentives. As a part of meeting the changing situation on global environmental problems after UNCED, and accommodation regulatory measures stipulated in the global environmental conventions and protocols, national policy will try to alter industrial and economic structure so as to mitigate the increasing trends of energy consumption, by encouraging energy conservation and efficiency. In this regard, more attention will be given to the policy on the development of the cleaner technology. Ultimately, these policies and programs will contribute greatly to improving the current state of national public health.

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The Development of a Multi-Purpose Irradiator and the Characteristic of Dose Distribution (다목적 방사선 조사장치 개발 및 선량분포특성)

  • Lee, Dong-Hoon;Ji, Young-Hoon;Lee, Dong-Han;Kim, Yoon-Jong;Hong, Seung-Hong
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.39 no.6
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    • pp.42-48
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    • 2002
  • The design, construction and performance test of a convenient multi-purpose irradiator is described. A multi-purpose irradiator using Cesium-137 has been developed for studies of low dose radiation effects in biology and for calibration of Thermo Luminescent dosimeter(TLD). During the operation, three rods of radioactive material which are 10cm in length revolve 180 degrees and irradiate biological samples, or TLD, and return to their shielded position, after the programmed time. A programmable Logic Controller(PLC) controls the sequence of operation, interlock, motor rotation and safety system. The rotation speed of biological samples can vary up to 20 RPM. A real time monitoring system was also incorporated to check and control the operation status of the irradiator. The capacity of the irradiation chamber was 4.5 liters. The isodose distribution at arbitrary vertical planes was measured by using film dosimetry. The dose-rate was 0.13 cGy/min in air and 0.11 cGy/min in water equivalent material in the case of Cesium-137. Range of activity was 2 Ci. The homogeneity of dose distribution in the chamber was ${\pm}$7%. The actual radiation level on the surface was within permissible levels. The irradiator had a maximum 0.35 mR/min radiation leakage on its surface.

Analysis of an internal flow with multi-perforated tube geometry in an integrated Urea-SCR muffler (다공튜브 형상변화에 따른 촉매 삽입형 Urea-SCR 머플러 내부유동 해석)

  • Moon, Namsoo;Lee, Sangkyoo;Lee, Jeekeun
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.5
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    • pp.500-509
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    • 2013
  • This study reports a numerical analysis of the internal flow characteristics of the integrated urea-SCR muffler system with the various geometries of the multi-perforated tube which is set up between the muffler inlet and in front of SCR catalysts. The multi-perforated tube is generally used to disperse uniformly the urea-water solution spray and to make better use of the SCR catalyst, resulting in the increased $NO_x$ reduction and decreased ammonia slip. The effects of the multi-perforated tube orifice area ratios on the velocity distributions in front of the SCR catalyst, which is ultimately quantified as the uniformity index, were investigated for the optimal muffler system design. The steady flow model was applied by using a general-purpose commercial software package. The air at the room temperature was used as a working fluid, instead of the exhaust gas and urea-water solution spray mixture. From the analysis results, it was clarified that the multi-perforated tube geometry sensitively affected to the formation of the bulk swirling motion inside the plenum chamber set in front of the SCR catalyst and to the uniformity index of the velocity distribution produced at the inlet of the catalyst.

Development of Door Control Unit for the Electric Plug-in Door of Subway Train (전동차 전기식 플러그도어 출입문 제어 장치 개발)

  • Joung, Eui-Jin
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.48 no.4
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    • pp.47-53
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    • 2011
  • The Electric Multiple Unit (EMU) has many types of door system such as sliding door, plug door etc.al. according to customer's requirements. The sliding door is widely used in Korea but has weak point in the noise problem. In the low operation speed, the noise coming from outer side of the EMU is not an important factor. As the speed is higher than before, noise is increased and make a problem. The main cause of noise is the imperfect air tightness in the EMU. The plug door system has advantages for the noise reduction characteristic in the high speed area. We have been developing electric plug-in door. The door is controlled by Door Control Unit(DCU) following the order of Automatic Train Protection (ATP) that is a kind of train signalling system. DCU has to simultaneously open and close the doors and the operation of it is related to the passengers safety. So DCU is a safety device that is important to reliability and safety. DCU is composed of several devices of control, motor driving, Input/Output, communication and power. In this paper, we will describe the functions, characteristic, requirement, subsystem and test results of DCU used for the electric plug-in door.

Removal of Volatile Organic Compounds (VOCs) of Deodorant by Adding a Metal Oxide to the Essential Oils (식물정유물질에 금속산화물을 첨가한 탈취제의 휘발성유기화합물질의 제거에 관한 연구)

  • Lim, You-Young;Lee, Min-Ho;Jeon, Soo-Bin;Yang, Kyeong-Soon;Jeong, Hae-Eun;Oh, Kwang-Joong
    • Clean Technology
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    • v.22 no.2
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    • pp.96-105
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    • 2016
  • VOCs emissions from industries cause the air pollution and odor. In the industrial facilities, the existing odor treatment techniques have limits and problems. In this study, the optimum essential oil and metal oxide selected by screening test. lavender oil, cypress oil and TiO2 were determined by deodorant materials and those were blended by 5%, 45%, 10%, respectively. In addition, the result of batch type experiments depending on the dilution rate, injection, rate, temperature showed that the optimum condition of deodorant is 6 mL of injection rate, and 200 times of dilution rate and the removal efficiency increased in proportion with temperature. In addition, the activation energy was calculated from the rate equation, which appeared in the 3-4 times lower than conventional deodorants.

Experimental investigation on valve rattle noise of automotive electronic-wastegate turbochargers (차량용 전자식 웨이스트 게이트 터보차져의 밸브 떨림음에 대한 실험적 고찰)

  • Park, Hoil;Eom, Sangbong;Kim, Youngkang;Hwang, Junyoung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.10a
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    • pp.686-686
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    • 2013
  • Automotive turbochargers have become common in gasoline engines as well as diesel engines. They are excellent devices to effectively increase fuel efficiency and power of the engines, but they unfortunately cause several noise problems. The noises are classified into mechanical noises induced from movement of a rotating shaft and aerodynamic noises by air flow in turbochargers. In addition to, there is a mechanical noise caused from movement of an actuator, electronically controlling a wastegate valve. It is called as valve rattle noise. The actuator is connected to a valve through a linkage. The noise occurs only if the valve is open, where the linkage is freely contact to neighbor structures without being constrained by any external forces. This condition allows impacts by the pulsation of exhaust gas, and the vibration from the impacts spreads out through turbine housing, causing the rattle noise. The noise is not in mechanical operating wastegate turbochargers because the linkage of an actuator is strongly connected by actuating force. For the electronic wastegate turbocharger, this paper proposed a test device to show the noise generating mechanism with a small vibration motor having an unbalanced shaft. It also shows how to reduce the noise - reduction of linkage clearances, inserting wave washers into a connection, and applying loose fitting in bushing embracing a valve lever to turbine housing.

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A Study on Vibration & Noise Reduction of Fast Back Feeding Device for Manufacturing Process (제조공정용 Fast Back 이송장치 진동·소음 저감에 관한 연구)

  • Han, Doo-Hee;Lee, Seung-Hun;Son, Yung-Deug
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.8
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    • pp.642-648
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    • 2019
  • This paper presents a fast back-type transfer device for snack food processing that uses the inertia of transferred material. A conventional conveying system is a drive system that uses a belt conveyor and mechanical crank, which generate noise and vibration and cause environmental pollution. Vibration and noise are reduced in the proposed fast back feeding device by using a counterweight. The crank drive unit was replaced with a linear servomotor, and an equilibrium device was designed to balance the force due to acceleration. This makes it is possible to adjust the forward and backward speed and acceleration through PLC control. A vibration damper device offsets the vibration force of the periodic shock form. The main cause of the vibration was identified through vibration analysis, and reduction measures were established. We verified the effectiveness of the vibration by making a prototype and performing about 10 vibration tests. Because no mechanical transducer is needed, energy loss, noise, and vibration do not occur, and the operating speed is not limited.

A Study of Working Environments and Workers Exposed to Chromium (크롬 취급 사업장의 작업환경 및 근로자 폭로 실태에 관한 연구)

  • Yu, Byung-Chul;Son, Byung-Chul;Jun, Jin-Ho;Han, Yong-Soo;Son, Hye-Sook;Lee, Chae-Eun;Jeong, Woon
    • Journal of Preventive Medicine and Public Health
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    • v.27 no.3 s.47
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    • pp.517-530
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    • 1994
  • For the purpose of providing the basic data for health management of workers who are exposed to chromium and for improving the quality of working environment, the authors evaluated blood and urinary level of chromium, the occupational history. AST, ALT, Hb, Hct, nasal specular examinaton on 287 workers who have been dealed chromium compounds in 56 manufacturing Industries of five types, that is, 38 metal plating services(plating),4 manufacture of other fabricated metal products (fabricated metal product), 5 manufacturing of dyestuff(dyestuff), 6 dressing and dyeing of leather(leather), 3 others(manufacture of pottery and ceramic househod wares, motor vehicles, electronic valves and tubes and other electronic components) and also measured the level of chromium in air from February to October 1993. The results were as follows ; 1. The utilized type of chromium compounds was the hexavalent state in plating fabricated metal product dyestuff, leather and the trivalent state in .other, and atmosperic chromium concentration as geometric mean was $0.0138mg/m^3(0.001{\sim}0.068mg/m^3)$ in plating, $0.0115mg/m^3(0.006{\sim}0.015mg/m^3)$ in fabricated matal product, $0.068mg/m^3(0.002{\sim}0.019mg/m^3)$ in dyestuff, $0.0083mg/m^3(0.002{\sim}0.028mg/m^3)$ in leather $0.0039mg/m^3(0.003{\sim}0.005mg/m^3)$ in other by the type of industry and it exceeded TLV-TWA ($0.05mg/m^3$) in five (13.6%) of plating services. 2. The geometric mean of chromium in blood was $1.54{\mu}g/dl(0.10{\sim}3.62{\mu}g/dl)$ in Plantng, $0.94{\mu}g/dl(0.27{\sim}2.82{\mu}g/dl)$ in fabricated metal product, $0.51{\mu}g/dl(0.10{\sim}3.25{\mu}g/dl)$ in dyestuff, $0.87{\mu}g/dl(0.15{\sim}8.00{\mu}g/dl)$ in leather, $0.55{\mu}g/dl(0.20{\sim}2.28{\mu}g/dl)$ in other by the type of industry(p<0.001). 3. The geometric mean of chromium in urine was $14.47{\mu}g/l(6.90{\sim}28.00{\mu}g/l)$ in planting, $4.63{\mu}g/l(0.24{\sim}43.00{\mu}g/l)$ in fabricated metal product, $5.93{\mu}g/l(1.00{\sim}33.00{\mu}g/l)$ in dyestuff, $11.09{\mu}g/l(0.80{\sim}48.00{\mu}g/l)$ in leather, $12.41{\mu}g/l(10.10{\sim}41.00{\mu}g/l)$ in other by the type of industry(p<0.001). 4. As the result of nasal specular examination, twenty four cases (8.4%) of nasal septal perforation among 287 total subjects was observed, and there were 17 (9.7%) cases in plating, 4 csaes (14.3%) in dressing and dyeing of leather. In the comparison of chromium concentration in blood and urine between the perforated group and non-perforated group, the perforated group showed a significantly higher value as $1.883{\pm}3.055{\mu}g/dl\;and\;0.793{\pm}0.815{\mu}g/dl$(P<0.001), $21.31{\pm}34.610{\mu}g/L\;and\;9.304{\pm}11.079{\mu}g/L$ (P<0.001). 5. The mean concentration of chromium in blood, urine and the mean level of AST, ALT, Hb and Hct in exposure group were higher than those of control group(p<0.001).

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Analysis of Respiratory Motional Effect on the Cone-beam CT Image (Cone-beam CT 영상 획득 시 호흡에 의한 영향 분석)

  • Song, Ju-Young;Nah, Byung-Sik;Chung, Woong-Ki;Ahn, Sung-Ja;Nam, Taek-Keun;Yoon, Mi-Sun
    • Progress in Medical Physics
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    • v.18 no.2
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    • pp.81-86
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    • 2007
  • The cone-beam CT (CBCT) which is acquired using on-board imager (OBI) attached to a linear accelerator is widely used for the image guided radiation therapy. In this study, the effect of respiratory motion on the quality of CBCT image was evaluated. A phantom system was constructed in order to simulate respiratory motion. One part of the system is composed of a moving plate and a motor driving component which can control the motional cycle and motional range. The other part is solid water phantom containing a small cubic phantom ($2{\times}2{\times}2cm^3$) surrounded by air which simulate a small tumor volume in the lung air cavity CBCT images of the phantom were acquired in 20 different cases and compared with the image in the static status. The 20 different cases are constituted with 4 different motional ranges (0.7 cm, 1.6 cm, 2.4 cm, 3.1 cm) and 5 different motional cycles (2, 3, 4, 5, 6 sec). The difference of CT number in the coronal image was evaluated as a deformation degree of image quality. The relative average pixel intensity values as a compared CT number of static CBCT image were 71.07% at 0.7 cm motional range, 48.88% at 1.6 cm motional range, 30.60% at 2.4 cm motional range, 17.38% at 3.1 cm motional range The tumor phantom sizes which were defined as the length with different CT number compared with air were increased as the increase of motional range (2.1 cm: no motion, 2.66 cm: 0.7 cm motion, 3.06 cm: 1.6 cm motion, 3.62 cm: 2.4 cm motion, 4.04 cm: 3.1 cm motion). This study shows that respiratory motion in the region of inhomogeneous structures can degrade the image quality of CBCT and it must be considered in the process of setup error correction using CBCT images.

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