• Journal of Advanced Marine Engineering and Technology
• /
• v.20 no.5
• /
• pp.45-57
• /
• 1996

Flow characteristics and contamination behavior in a three-dimensional room with the desk-type obstacle have been investigated numerically by the k-${\varepsilon}$ two equation turbulence model. The room model has one supply opening on the ceiling and two exhaust openings on the side walls. Thirty six sets of calculation have been performed for twelve contamination sources of $1{\times}10^{-4}kg_c/(m^3{\cdot}s)$ strength at different inlet velocities(0.1, 1, 10m/s). This study can conclude that the source points of contaminant are located near the obstacle edge of Z-axis, at which the maximum contaminant diffusion fields are occured.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.4
• /
• pp.183-188
• /
• 2003

Particulate contamination is known to be a significant cause of failures of removable storage media. In this work, the effect of particles on the surface damage of removable hard disk media was investigated. The particles of different materials and size were introduced to the Head Disk Interface (HDI) using a particle injection system. It was round that the particles of particulate size and property serious damaged the media. This study showed that cleaning pad is effective for reducing particle contamination, except fer the particles of specific size and property. As a means to remove the particles of specific sire. the concept of using a stepped taper at the leading edge of the slider is proposed.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.946-949
• /
• 2002

Particulate contamination is known to be a significant cause of failures of removable storage media. In this work, The effect of particles on the surface damage of removable hard disk media was investigated. The particles of different materials and size were introduced to the head-disk interface using a particle injection system. It was found that the particles of particulate size and property serious damaged the media. This study showed that cleaning pad is effective for reducing particle contamination, except for the particles of specific size and property. As a means to removed the particles of specific size, the concept of using a stepped taper at the leading edge of the slider is proposed.

• Journal of Korea Port Economic Association
• /
• v.19 no.1
• /
• pp.113-138
• /
• 2003

With it being inevitable to change the method of supervising as it is reorganized to EEZ coming out of the old concept of contamination in Korean area of the sea, it costs a lot to have good enough systems of total control for sea contamination and prevention of contamination as well as the effective marine superintendence because the governing bodies such as Ministry of Maritime Affairs and Fisheries, National Maritime Police Agency, and Authorities of Guiding Ships for Fishery, have their own source of laws and different ways to execute. In order to change such a wrong method of marine superintendence, it is necessary to conduct the merger and abolition of similar authorities with similar functions into authorities which are light but can be expected to play a major role, and to open the high-costing low-efficient organizations to make them remodel to be reborn as economical bodies. In addition to that, the maritime authorities, which are falling to incapable organizations not being able to work out any complicated tasks, have to be reborn as preventing bodies which take care of security and public peace and cut off a pollution source from sea and land.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.12 no.1
• /
• pp.3-12
• /
• 2008

Purpose: Contaminated clothes and bedclothes of patients by mouth or with excrement are produced after Radioisotope $^{131}I$ treatment. In this paper, patient's clothes and bedclothes contaminated by radioactivity measured and radioactive waste wish to calculate optimum storage period. Material and Methods: The whole area of patients' clothes and bedclothes measured 70 patients, 12 males and 58 females, who had radioisotope $^{131}I$ therapy between August 2005 and February 2006. Assuming contamination is evenly distributed, the radioscope used to measure up to social toleration level at 7 day intervals. Results: Each optimum storage period of control group of 60 case and non control group of 10 case were average $44{\pm}16$ days and $32{\pm}13$ days. Decontamination effect of surface contamination for radioactive waste was average $83.66{\pm}15.15%$. Conclusion: It is important that classify radioactive waste according to difference of surface contamination. Result of this research, handling radioactive waste in optimum storage period may be useful.

• Journal of Soil and Groundwater Environment
• /
• v.10 no.2
• /
• pp.28-34
• /
• 2005

The aim of this article is to assess the application characteristics of the site by remediating oil-contaminated area using DSB (Deep-site Biopile) system. In the contaminated area, the soil was composed of penetrable sand and the leaked oil was spread widely (total 7,201 cubic meters) through 2.5 meter deep underground water flow. DSB system was operated for 30 minutes intervals for 24 hours in a day (30 minutes opεration and 30 minutes stop). To check contamination level change in the contaminated area after DSB system was operated, samples were taken. The result from the site shows that BTEX/TPH contamination level was dropped 50% after 30-day operation of DSB system, and that contamination level was dropped below contamination level check standard after 165 days and the remediation was completed. Unlike traditional biological remediation methods DSB system could efficiently process soil and water which were contaminated by high levels of oil compounds.

• Journal of the Korean Vacuum Society
• /
• v.11 no.2
• /
• pp.87-96
• /
• 2002

Outgassing from such sources as paints, coatings, adhesives and other non-metallic surfaces can contaminate satellites, especially second surface mirror and optical lens, it cause satellite to fail in own missions. The vacuum bake-out test using high temperature(more than $85 ^{\circ}C$)and high vacuum(less than $5.0{\times}1-^{-3}$ Pa) certify that the components of satellite work properly and can survive and operate in space environment like high vacuum. In the bake-out chamber installed at SITC of KARI, Rotary vacuum pump and Booster pump produce low vacuum of 5.0 Pa, and then two cryopumps produce high vacuum of below $5.0{\times}10^{-3}$ Pa. Also 48 ceramic heaters were provided to simulate high temperature. During the vacuum bake-out test, we detected contaminants using RGA(Residual Gas Analyzer) and measure the outgassing rate of the contaminant using the TQCM(Thermoelectric Quartz Crystal Microbalance). Also, IR/UV Spectrometer and witness plate be used to certify that the components were suitable for the spacecraft. This paper includes the preparation and procedures of the bake-out test for SAR(Solar Array Regulator) and MLI(Multi Layer Insulator), which were the components of the spacecraft. Especially, we discussed the methods and results of the contamination measurement. In the bake-out for SAR, the contamination was measured continuously although it was on the decrease from TQCM results. And RCA established that it is a highly polymerized compound. In the MLI bake-out using RGA and witness plate, we didn't detect any contamination materials.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2001.09a
• /
• pp.122-140
• /
• 2001

We have applied the geophysical survey, mainly electric and electromagnetic (EM) methods, to a test site contaminated by hydrocarbon waste disposal and local spill. The multi-frequency, moving source & receiver EM survey along with ground penetrating radar (GPR) showed a fairly good performance in detection of buried metal pipes and objects. Magnetic survey measuring vertical and horizontal gradients were so sensitive to the small metallic objects spread over the surface that it's hard to discriminate the buried pipe. We chose electrical resistivity, EM and GPR survey to examine the soil contamination. Depth slices of resistivity distribution as the results of the inversion of resistivity and EM data coincided each other and closely matched the contaminated area determined by chemical analysis of the soil samples. GPR images did not show the reflection events related with contamination plume since there are no distinct spill in this site. We inferred the contamination using the penetration depth of the GPR energy, which could be used as auxiliary information to the resistivity and EM results. We summarized the applicability of each survey methods based on this results and proposed a desirable survey scheme for the determination of hydrocarbon contaminated site.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.2
• /
• pp.128-132
• /
• 2010

Purpose: Nuclear medicine general operation room is radioactive control room which is used for the handling of radioisotope(R.I). Radioactive contamination materials must be under control and separated from general trash. With this experiments, we want to actively suggest the guideline of controling and operating radioactive contamination materials by measuring contamination degree and analyzing the causes which is not realized so far. Materials and Methods: Materials are selected from Oct. 2009 to March. 2010. salines which are used for labelling radiophamaceuticals and generator cap, saline needle cap, $^{99m}Tc$-needle cap saline vial which is generated from $^{99}Mo$/$^{99m}Tc$ generator. After measuring each surface contamination degree by survey meter, mean value and standard deviation one were solved out. Results: In result, After measuring surface contamination degree, radioactivity of saline for labelling radiophamaceuticals showed $14429{\pm}26378$ cpm (p<0.05) and in measured generators, foreign imported things showed that generator cap : $9{\pm}21$ cpm, saline vial : $17{\pm}28$ cpm. saline needle cap : $35{\pm}66$ cpm, $^{99m}Tc$-needle cap : $9{\pm}21$ cpm, saline vial $13{\pm}28$ cpm. domestic things showed that generator cap : $22852{\pm}52545$ cpm, saline needle cap : $87367{\pm}109711$ cpm, $^{99m}Tc$-needle cap : $9008{\pm}10459$ cpm, saline vial : $186416{\pm}158196$ cpm (p<0.05). Conclusion: The saline which is used for labelling, exceeded 1/10 of maximum permissible range. this is generated from radiophamaceuticals dilution procedure. and In generators, radioactive value of foreign import things showed closely background value. but which of domestic thing showed that exceeded more than 1000 values 1/10 of maximum permissible range. the causes of that is domestic generator is contaminated in manufacturing procedure. So, to dispose radioactive contamination materials which is could betaken out of, the control and operation must be radical under controlled by radioactive measuring, recording and equipping of its own. if this is kept well, we can prevent surely that radioactive waste could be disposed like as general trash.

• Journal of Korean Academy of Fundamentals of Nursing
• /
• v.18 no.4
• /
• pp.472-479
• /
• 2011

Purpose: The purpose of this study was to develop guidelines for cleaning of enteral nutrition bags by comparing the level of equipment contamination according to cleaning and disinfection methods. Method: This study was a true-experimental study, with 60 cases in total. Twenty cases each were randomly assigned to tepid water, detergent and brush, and disinfectant groups. The period of the experiment was March to April 2010, and enteral nutrition was given for 1 houre, 3 times a day at 7AM, noon, and 7PM for seven days. Enteral nutrition bags were cleaned after each feeding according to assigned cleaning and disinfection method followed by microbial cultures on 4th and 8th day before the 7AM feeding. Results: After 3 days of feeding and cleaning, the level of contamination of bags was not significantly different among the three groups. After seven days, the level of contamination was significantly lower when bags were cleaned with detergent and brush or with disinfectant compared to cleaning with tepid water. Conclusion: In cases where enteral nutrition bags are reused for example, in home care settings, studying findings indicate that cleaning bags using detergent and brush or disinfectant is an effective way to prevent contamination of bags.