• Journal of the Korean Society of Radiology
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• v.12 no.6
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• pp.769-776
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• 2018

According IEC 60601-1 ed3.1 and IEC 60601-2-45 regulation, diagnostic X-ray equipment should be display to measured and calculated air kerma area product. On the clinical X ray equipment, air kerma area product dosimeter would like to have an evidence for dosimeter accuracy and energy dependency. This study was performed to indirect calibration and energy dependency test for attached type air kerma area product (KAP) dosimeter by RQR standards beam quality. On the RQR5 beam quality, attached KAP dosimeter error showed -7.5%, respectably. On the RQR9 beam quality, attached KAP dosimeter error showed -10.4%, respectably. All RQR beam quality, average absolute error was $8.30%{\pm}2.85%$, respectably. On this study, attached KAP dosimeter was satisfied to IEC 60580 and AAPM TG 190. This calibration method of KAP dosimeter will help to performance maintain for clinical KAP dosimeter.

• Analytical Science and Technology
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• v.13 no.2
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• pp.222-228
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• 2000

A detector for monitoring carbon monoxide (CO) in ambient air by nondispersive infrared (NDIR) spectroscopy has been developed and investigated its sensitivity and stability. The essential parts of the absorption cell are three spherical concave mirrors so as to improve the sensitivity by increasing the light path length in the cell. The radius and center of curvature of mirrors and position in the cell was calculated by computer simulation in order that the light path length may be 16m into the 50cm cell. The number of traversals and optical path properties were confirmed by laser beam alignment in transparent absorption cell. The photoconductive type lead selenide (PbSe) was used as CO sensing material, which was cooled to increase the responsibility by thermoelectric cooling method. The detection limit and span drift of the developed CO detector was 0.24ppm and 0.03ppm(v/v) respectively.

• Journal of Biosystems Engineering
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• v.13 no.3
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• pp.81-90
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• 1988

Agricultural and municipal wastes arc serious nuisance. in Korea. Disposal of these wastes by land application, incineration or burial have created serious environmental problems such as air pollution and ground water contamination. Uncomposted waste materials are also potential sources of plant and soil pathogens. As available sites for waste burial become more difficult to find and air quality standards for incineration become stricter, composting as a method for treating solid wastes will become more attractive. This article discussed the recent topics on composting to further develop a rational strategy. The future of composting is developed based on the interacting factors of the price of energy and fertilizer, public policy, economic considerations, and biotechnology.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.1
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• pp.69-77
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• 2000

This paper summerizes the results of the first proficiency testing program for achieving the analytical quality assurance of anions and metal ions in air borne particles in Korea. This program covered the chemical testing of anions(Cl-, NO3-, SO42-) and metals(Fe, Pb, Zn) in qeueous solution. The exercies was conducted by the Measurement & Analysis Committee of Korean Society for Atmospheric Environment(KOSAE). Pilot lab. was Division of Chemical Metrology and Materais Evaluation in Korea Research Institute of Standards and Science(KRISS). A total of 11 laboratories participated in the program. Two samples of 100mL in low density polyehylene bottles were supplied to participating laboratories. The proficiency testing results were interpreted by two graphical methods, Youden polt and x-Charts(control chart).

• Asian Journal of Atmospheric Environment
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• v.6 no.3
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• pp.169-191
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• 2012

This review paper describes the ambient air PAH concentrations in different developing Asian countries, including China, Afghanistan, India, Malaysia, Turkey, Vietnam, Sri Lanka, Thailand and Cambodia. In this study, more than 75 research papers published in the English literature were reviewed with respect to the seasonal and locational concentrations of PAHs in each of 9 different Asian countries. This study compared, discussed and tabulated the PAH concentrations in developing Asian countries over a one decade (2000-2011) period. The PAH concentrations measured in developing countries highlights the necessity to improve the air quality in those countries. Compared to the developed nations in Asia, developing countries are almost one decade away from implementing environmental policies, such as Euro standards. This review discusses the reasons for the high PAH concentrations in developing nations particularly in China and India. Based on the literature available, some suggestions are made to reduce the concentrations of PAHs in the ambient air of developing nations. The total data obtained from the literature survey is tabulated and presented as supplementary information at the end of the manuscript.

• Journal of the military operations research society of Korea
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• v.34 no.3
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• pp.31-40
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• 2008

The aircraft manufacturing industry is a profitable business and has the potential to be an important export business. Our trade deficit needs to be improved in aircraft manufacturing part. Our national aircraft industry, which has been recognized for its quality in many domestic and international Air Shows, has developed the T/A-50 aircraft from the origins of the KT-1. With the ongoing development of the next generation fighter planes and helicopters, business for the next generation domestic air cargo has bright prospects. Judging by the history of the overseas air force dispatch during the Vietnam, Gulf, and Iraqi wars whose main mission was air transportation, there will be many opportunities to show the excellence of Korean air cargo in the future. The purpose of this study is to discover the optimal scale of air cargo development using the AHP method. The authors evaluated the scale of air cargo in size and capacity based on the following 5 standards used Korean developing airliner: usability, economics, technology, safety, and environmental friendliness. Then, the authors modified specific standards suitable for air cargo based on literature review Decision-making groups were chosen for suitability of expert staff in charge because they could represent for leading opinions in this specialized area especially as in practical aspects. The participants of the evaluation were pilots, transportation officers and management staff in the KAI who have experienced over 5years.

• Analytical Science and Technology
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• v.23 no.2
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• pp.138-146
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• 2010

The Korean Ministry of the Environment revised a few sections of the regulations in the Law of indoor air quality management for the reinforcement or adjustment of the regulation criteria standard for releasing pollutants from building materials. Especially, in case of sealant, the contents covering liquid building materials, excess standards and testing methods have been added simultaneously in this revision, As a result it is impossible to compare original standards with revised standards directly. For this reason, this study reviewed revised test method of sealant pollutant emission rates in terms of impact and validity in comparison with the original test method. Through this study, the basic properties of revised pollutant emission control standards was assessed. Especially in sealant, since each product has a wide deviation of time required for complete drying, it is proved that there are a large number of products that are not hardened completely in test time. The result of our experiments on the revised test methods showed that this revised test methods yield emission rates that are two and half times less than those of the original testing method. To apply the revised test method of sealant to all the sealant products, It is necessary to extend the test period or improve specimen to fit the test method for quickly drying sealant products.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.3
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• pp.273-278
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• 1995

This study is to estimate the ventilation volume by the traffic that originated from driving automobiles for two tunnels (Kugi tunnel and Kumhwa tunnel) that adopted natural ventilation system among tunnels of Seoul, and on the basis of which, we estimated the ventilation velume at various conditions. With the result of the estimation, we will present the basic method that can be operated with the optimum condition for the ventilation system. Estimating the predicted ventilation volume in the tennel by the pollutant concentration, we used traffic volume and CO emission data by the automobile speed and CO concentration in the tunnel. And, when we estimated the traffic ventilation volume by natural and traffic ventilation force, we used traffic volume, automobile speed, tunnel area, automobile area data and so on. As the result of simple regression between predicted ventilation volume and traffic ventilation volume, we attained the regression coefficient 0.88, and achieved the relation form that predicted ventilation volume equal 0.12x traffic ventilation volume-92, 000. Using this equation, we estimated the ventilation volume to satisfy the enviromnental standards of several space, and calculated the required volume for mechanical ventilation. Incase of Kumhwa Tunnel, there is a need of mechanical ventilation all day long to satisfy air quality standard 9 ppm for 8 hours average and 10 ppm for the indoor air quality standard of public facilities.

• Journal of Environmental Health Sciences
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• v.19 no.1
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• pp.37-43
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• 1993

The airborne concentrations of Sulfur Dioxide and Total Suspended Particulates were investigated in 4 subway lines in Seoul at early summer, 1990 and early summer, 1991. The results of the study were as follows: 1. The airborne concentrations of SO$_2$ and TSP were 0.022 ppm, 445.7 $\mu$g/m$^3$ respectively. And percents of over annual air quality standard of WHO was that SO$_2$ and TSP were 41.7%, 100% respectively. 2. Airborne SO$_2$ concentrations by subway lines were that line 1 was 0.025 ppm, line 2 was 0.023 ppm, line 3 was 0.020 ppm, and line 4 was 0.017 ppm. And TSP concentrations by subway lines were that line 2 was 533.8 $\mu$g/m$^3$, line 1 was 516.5 $\mu$g/m$^3$, line 4 was 371.6 $\mu$g/m$^3$, and line 3 was 369.3 $\mu$g/m$^3$ 3. Annual variation of concentration of TSP was not significant statistically (t=0.327), and that of SO$_2$, in 1990 was slightly higher than that in 1991 (t=1.433, p<0.1). 4. Coefficients of correlation between TSP and SO$_2$ by years were that early summer, 1990 was r=0.277 (p>0.1), and early summer, 1991 was r=0.32 (p>0.1).

• Analytical Science and Technology
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• v.27 no.6
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• pp.357-363
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• 2014

Isoprene is a one of the biogenic volatile organic compounds (BVOCs) and it is known as a source of the tropospheric ozone and formaldehyde. In addition, isoprene is a trace component of the exhaled breath and it is a potential biomarker for the diagnosis of diseases such as lung cancer. In these regards, isoprene gas standards are required for the accurate measurement of isoprene in air samples. To establish a standard for isoprene gas, gravimetric preparation and characterization of primary gas standards were studied. The primary gas standards were produced independently in 4 aluminum cylinders and concentrations were examined by GC-FID. As a result, the uncertainty of the gravimetric preparations including purity of the raw material was 0.01% and reproducibility of the preparation of independent 4 cylinders was 0.08%. The primary gas standards for isoprene showed 14 months of long-term stability. The relative expended uncertainty of 2.8% (95% of confidence level, k=1.96) was assigned to the certified value of 10 ${\mu}mol$/mol level of isoprene based on the quantitative evaluation of the purity, weighing, reproducibility, adsorption and long-term stability.