• Title/Summary/Keyword: Safety of Facilities

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Evaluation of the Properties of an Environment-Friendly De-icing Agent Based on Industrial By-Products (산업부산물을 활용한 친환경제설제의 특성평가)

  • Heo, Hyung-Seok;Lee, Byung-Jae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.6
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    • pp.132-139
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    • 2017
  • A huge amount of de-icing agent is sprayed during winter to promote traffic safety in cold regions, and the quantity of de-icing agent sprayed has increased each year. The main ingredients in commonly used de-icing agents are chlorides, such as calcium chloride($CaCl_2$) and sodium chloride(NaCl). While calcium chloride is mostly used in Korea and sodium chloride is usually used in the U.S. and Japan, all de-icing agents include chloride ions. The chlorides included in sprayed calcium chloride-based de-icing agents have severe adverse effects, including the corrosion of reinforcing steels through salt damage by infiltrating into road structures, reduced structural performance of pavement or damage to bridge structures, and surface scaling, in combination with freezing damage in winter, as well as water pollution. In addition, the deterioration of paved concrete road surface that occurs after the use of calcium chloride-based de-icing agent accelerates the development of visual problems with traffic structures. Therefore, the present study was performed to prepare an environment-friendly liquid de-icing agent through a reaction between waste organic acids and calcium-based by-products, which are industrial by-products, and to analyze the properties of the de-icing agent in order to evaluate its applicability to road facilities.

Estimated Additional Number of Workers and Additional Collective Dose by Reducing Dose Limits (선량한도 하향이 방사선작업인력 및 집단선량에 미치는 영향예측)

  • Ha, Chung-Woo;Na, Seong-Ho
    • Journal of Radiation Protection and Research
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    • v.23 no.3
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    • pp.149-157
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    • 1998
  • An analysis has been performed to estimate the additional number of workers and the additional collective dose in man-cSv which would be required, nuclear industry-wide as a result of reducing individual dose limit. This analysis can be extended to the reduction in the dose limits recommended by ICRP Publ.60 and BEIR V report as well as the proposed dose limits by regulatory authorities. An industry-wide database was employed in the analysis based on a summary of industry-wide occupational radiation exposure compiled by the Korea Radioisotope Association. Correlation model was employed to compute the affects of setting specific annual individual dose limits. In this study, we have addressed worker non-productivity while in the radiation environment on a parametric or 'sensitivity analysis' basis. This alleviates the need for developing such data underlying a summation of many individual tasks at many nuclear facilities. It has the advantage that very low non-productivity assumptions can readily be defended as conservative, in that it is difficult to approach such low worker non-productivity factors even in the best of environments in any industry. On a per facility basis, for calendar year 1997, the number of workers required would be increased from 231 workers to 269 workers and collective man-cSv dose would be also increased by approximately fourteen percent if the individual dose limit was reduced to 2 cSv/y and an individual worker non-productivity fraction of 0.1 is assumed.

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A Conspicuity Effect Study of Fluorescent Orange Color Traffic Sings for Work Zone Application (공사구간 형광주황색 교통안전표지 적용에 따른 주목성 효과 연구)

  • Ko, Sangkeun;Choi, Keechoo;Lee, Sang-Soo;Yun, Ilsoo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.5D
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    • pp.437-444
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    • 2012
  • This study intended to improve traffic safety in work zones using fluorescent orange color traffic signs. For this end, the current problems of existing traffic signs and facilities in work zones were analyzed and some good examples of foreign countries were compared. More specifically, in order to identify current problems, the basic shape and color of traffic signs in use were examined through literature review, surveys and field studies. It was found that the fluorescent color worked more effectively than other colors in terms of visibility and conspicuity in work zone sign system. For evaluation, both Conspicuity surveys and in-door simulator experiments were conducted to effectively assess the merits and demerits of different types of traffic signs for work zones. The results of evaluations showed that black lettering on a fluorescent orange background outperformed more than 70% in terms of visibility and ability to call drivers' attention compared with those from black/red lettering on yellow/white backgrounds currently used at work zones on expressways and national highways. In addition, simulated driving experiment disclosed that drivers recognized the fluorescent orange background sign 15m ahead compared with the yellow background sign and 25m ahead compared with the white background sign, respectively. As for the diamond-shaped "Under Construction" sign, drivers recognized fluorescent orange background 11m ahead compared with the yellow background sign and 19m ahead compared with the white background sign, respectively.

Drivers' Understanding of Traffic Pavement Markings (교통노면표시 이해도에 관한 연구)

  • Shin, Kangwon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.2
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    • pp.711-718
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    • 2013
  • Traffic pavement markings are one of primary transportation facilities that provide drivers with various road information directly. Thus, a clear understanding of traffic pavement markings is utmost important to improve traffic safety as well as to establish a proper traffic culture. However, no past studies examined drivers' understanding of traffic pavement markings in Korea. Hence, this study investigated drivers' understanding of traffic pavement markings through an elaborated administrated survey, and analyzed the relationship between various drivers' characteristics and understanding regarding pavement marking via cross-classification table and logistic model. The analysis results show that drivers have limited understanding regarding the purpose of the markings. Specifically, the average understanding of pavement markings is 57.41%: the lowest understanding is 25.88% for yield pavement marking, and the highest understanding is 91.18% for advanced pedestrian crosswalk pavement marking. This study also revealed that the understanding of some pavement markings are somewhat influenced by user group such as drivers with suspended or revoked driver licenses, but the overall understanding of pavement markings are not significantly affected by drivers' characteristics such as gender and driving experiences at ${\alpha}$=0.05. Thus, it might be desirable for policy makers to establish pavement marking-related policies for overall drivers rather than specific drivers.

Illuminance Effects Affecting to Cognitive Ability of the Elderly (고령자의 인지력에 미치는 조도의 영향)

  • Kim, Myung-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.507-512
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    • 2019
  • To study how illuminance affects cognitive ability of the elderly, the elderly's EEG, concentration, HRV and vibra image were measured in a test room with temperature $25[^{\circ}C]$, relative humidity 50[RH%] and air flow speed 0.02[m/sec] by varying illuminance to 100[lux], 300[lux], 600[lux], 1000[lux] and 1500[lux]. Ten active elderly males were selected as subjects. Experiment condition was fixed as 1met of activity amount where the subject is seated and relaxed with cloth amount of 0.7clo. As a result, 1000[lux] was found out to be the most pleasant illuminance for the elderly, because $M{\beta}$ increased by 66.35%, and $S{\alpha}$ increased by 31.57% when the elderly was under 1000[lux] of illuminance. Also, concentration under 1000[lux] increased by 8.83% compared to 100[lux], and the pattern of concentration maintained uniformly. SDNN increased by 74.94% under 1000[lux] compared to 100[lux]. Nervousness decreased by 97.23% under 1000[lux] compared to 100[lux]. Moreover, HRT notably increased and aggression remarkably decreased under illuminance of 1000[lux]. Thus, based on the fact that comfort, concentration and heart stability of the elderly reach the highest under 1000[lux], it is determined that the illuminance has to be considered foremost in designing the elderly's welfare facilities to raise their safety and level of independence.

Seismic Performance Evaluation of Concrete Anchors used in Power Plant Equipment by Shaking Table Tests (진동대 실험을 통한 발전기기용 콘크리트 앵커의 성능평가)

  • Lee, Sang-Moon;Jeon, Bub-Gyu;Jung, Woo-Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.41 no.1
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    • pp.21-28
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    • 2021
  • The main purpose of this study is to assess the safety of the fixed anchorages subjected to the seismic motion for an operating facilities in the actual power plant. Thus, the experimental study was conducted to investigate the load response in the event of an actual seismic to the anchorages of a nonstructural components. Since there are economic and spatial constraints to study nonstructural components that actually have various forms, alternative test specimens of steel frames with mass were built and the shaking table test was carried out. In order to evaluate the dynamic characteristics and seismic performance, the natural frequency of the target structure was identified through the shaking table test and then the load response characteristics of the anchorage were evaluated by generating an artificial seismic effect like actual seismic. Finally, the structural stiffness was reinforced by fixing the steel frame to the test specimen using bolts, thereby reducing the load transmitted to the anchorage. It will be carried out on the reliability verification of the experiments and areas that have not been carried out due to the site conditions through the analytical approach in the future.

A Proposal for the Management Standards of Radioactive Mixed Waste in Korea (한국의 방사성혼합폐기물 관리기준 제안)

  • Lee, Byeong Gwan;Kim, Chang Lak;Lee, Sun Kee;Kim, Heon;Sung, Suk Hyun;Park, Hae Soo;Kong, Chang Sig
    • Journal of the Korean Society of Systems Engineering
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    • v.17 no.1
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    • pp.85-96
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    • 2021
  • Radioactive mixed waste (RMW) means waste mixed with radioactive substances and hazardous substances. In Korea, there are definitions and disposal restrictions on RMW in the Nuclear Safety Management Act, but it is difficult to apply because the contents are insufficient, so this paper proposed applicable management standards. The main RMW generated from nuclear power plants is waste oil, waste asbestos, PCB, and waste fluorescent liquid, and their radiation characteristics are mostly at very low levels and some are estimated at low levels. In addition to nuclear power plants, RMW also occurs in research institutes, industries, and hospitals. The acceptance criteria of all disposal facilities in the world basically prohibit disposal of RMW unless the hazardous substances of RMW are removed or mitigated below the standard value. Cases in Korea, the United States, Japan and Europe were reviewed to propose the RMW management standards in Korea. With reference to the results of the above review, this paper clearly defined RMW and proposed detailed management standards for the separation, storage, treatment and disposal of hazardous substances by applying the Waste Control Act. It also mentioned legislation of management standards, regulatory methods, and acceptance criteria of disposal facility operator.

Research on the Necessity of Building the Second Space Rocket Launching Sites for Breakthrough Development of R.O.K National Space Power (도약적 국가 우주력 발전을 선도할 제2 우주센터 구축 필요성 연구)

  • Park, Ki-tae
    • Journal of Space Technology and Applications
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    • v.2 no.2
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    • pp.146-168
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    • 2022
  • Witnessing current military conflicts in South China Sea and Eastern Europe, most defense analysts evaluate one of the most serious security threat toward the US is coming from the superpower competitions with Russia and China. The main means for such super power hegemonic competitions is military power and space power is a key enabler to maximize the efficiency and effectiveness of military employment. Reflecting above circumstances, the space hegemonic competition between the Unites States and China is spreading into all aspects of national powers. Under such an environment, R.O.K needs to significantly develop national space power to preserve life and assets of people in space. On the other hand, the R.O.K has a lot of limitations in launching space assets into orbits by land-based space rockets due to its geographic locations. The limitation of rocket launching direction, the failure to secure a significant area enough to secure safety and the limitation to secure open area enough to build associated facilities are among them. On this paper, I will suggest the need to build the 2nd space rocket launching site after analyzing a lot of short-falls the current 'Naro' space center face, compared to those of advanced space powers around the world.

A Study on the Exposure Dose of Frequent Workers and Radiation Workers in a University Hospital (일개 대학병원의 수시출입자와 방사선작업종사자의 피폭선량에 관한 고찰)

  • Joo-Ah Lee
    • Journal of the Korean Society of Radiology
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    • v.17 no.4
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    • pp.581-587
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    • 2023
  • In this study, we tried to provide basic data for radiation safety management by comparing and analyzing the exposure doses of radiation workers and frequent workers at C University Hospital in Incheon. From January 2021 to December 2022, surface dose and deep dose were analyzed for 30 radiation workers and 8 frequent workers who worked at C university hospital in Incheon. Radiation workers were targeted at radiation technicians and nurses working in the radiation oncology department and nuclear medicine department, and frequent visitors were targeted at frequent workers who manage and clean facilities in the same radiation management area. In the radiation worker group, 3.1 per 10,000 radiation technologist, 1.2 per 100,000 nurses, and 4.5 per 1,000,000 frequent workers showed the possibility of developing side effects on the lungs. The probability of radiation oncology was 1.1 per 10,000 for radiation technologist and 5.2 per 1,000,000 for nurses, and the probability of radiation technologist in nuclear medicine was 2.9 per 10,000 and for nurses was 7.1 per 1,000,000. It is hoped that this study can be used as basic data in future revisions on frequent workers, and it is considered that it will be used as basic data in the field of obstacles in relation to the stochastic effect of radiation in the future.

Extraction of Road Information Based on High Resolution UAV Image Processing for Autonomous Driving Support (자율주행 지원을 위한 고해상도 무인항공 영상처리 기반의 도로정보 추출)

  • Lee, Keun-Wang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.8
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    • pp.355-360
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    • 2017
  • Recently, with the development of autonomous vehicle technology, the importance of precise road maps is increasing. A precise road map is a digital map with lane information, regulations, safety information, and various road facilities. Conventional precise road maps have been tested and developed based on the mobile mapping system (MMS). But they have not been activated due to high introduction costs. However, in the case of unmanned aerial vehicles (UAVs), the application field is continuously increasing. This study tries to extract information through classification of high-resolution UAV images for autonomous driving. Autonomous vehicle test roads were selected as study sites, and high-resolution orthoimages were produced using UAVs. In addition, the utilization of high-resolution orthoimages has been proposed by effectively extracting data for precise road map construction, such as road lines, guards, and machines through image classification. If additional experimentation and verification are performed, the field of UAV image use will be expanded, providing the data to automobile manufacturers and related public and private organizations, and venture companies will contribute to the development of domestic autonomous vehicle technology.