• Title/Summary/Keyword: Safety Engineering

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Experimental Study on Loading Capacity of SY Corrugated Steel Form for RC Beam and Girder (SY 비탈형 보거푸집의 내하성능에 관한 실험적 연구)

  • Bae, Kyu-Woong;Boo, Yoon-Seob;Hwhang, Yoon-Koog;Shin, Sang-Min
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.25 no.5
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    • pp.32-39
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    • 2021
  • Recently, necessities of steel form for reinforced concrete beam and girder have been emphasized in building structures for the reduction of the construction period and the labor cost. SY Beam was developed for the these purposes and is roll-formed using thin steel plate. On this research, we tried to evaluate and verify the performance and behavior of SY Beam under construction loading stage as like pouring in situ concrete. For the standard shape of SY beam, structural modelling with various steel thicknesses has carried out using MIDAS GEN program. From results of modelling, the width and height of SY Beam were determined 600mm and 400mm respectively. For 3 SY Beams, the loading experiment was performed to measure vertical and horizontal displacement under stacking sand, concrete block, and bundle of rebar. As a result, the vertical deflection showed a tendency to decrease as the thickness increased. In the horizontal displacement, the trend according to the thickness was not clearly observed. From the evaluation on the loading experiment, it is considered that the SY Beam can secure both workability and structural safety. In particular, the SY Beam(1.2mm) hardly generates horizontal displacement, so it has excellent load-bearing capacity. So, we judged that the SY Beam with 1.2mm steel plate has excellent performance and consider to be immediately commercially available.

Modelling on the Carbonation Rate Prediction of Non-Transport Underground Infrastructures Using Deep Neural Network (심층신경망을 이용한 비운송 지중구조물의 탄산화속도 예측 모델링)

  • Youn, Byong-Don
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.4
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    • pp.220-227
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    • 2021
  • PCT (Power Cable Tunnel) and UT (Utility Tunnel), which are non-transport underground infrastructures, are mostly RC (Reinforced Concrete) structures, and their durability decreases due to the deterioration caused by carbonation over time. In particular, since the rate of carbonation varies by use and region, a predictive model based on actual carbonation data is required for individual maintenance. In this study, a carbonation prediction model was developed for non-transport underground infrastructures, such as PCT and UT. A carbonation prediction model was developed using multiple regression analysis and deep neural network techniques based on the actual data obtained from a safety inspection. The structures, region, measurement location, construction method, measurement member, and concrete strength were selected as independent variables to determine the dependent variable carbonation rate coefficient in multiple regression analysis. The adjusted coefficient of determination (Ra2) of the multiple regression model was found to be 0.67. The coefficient of determination (R2) of the model for predicting the carbonation of non-transport underground infrastructures using a deep neural network was 0.82, which was superior to the comparative prediction model. These results are expected to help determine the optimal timing for repair on carbonation and preventive maintenance methodology for PCT and UT.

A Scientific Critique of a Korean Court's Acquittal for Involuntary Manslaughter Related to 5-chloro-2-methylisothiazol-3(2H)-one/2-methylisothiazol-3(2H)-one (CMIT/MIT), a Humidifier Disinfectant (HD) Part I: Material safety, exposure and delivery to target organ from an HD perspective (CMIT/MIT 함유 가습기 살균제 제품의 제조 및 판매기업 형사판결 1심 재판 판결문에 대한 과학적 고찰 (I) - 제품 위험성과 노출평가 측면에서)

  • Park, Dong-Uk;Zoh, Kyung Ehi;Kim, Jiwon;Choi, Sangjun;Kwon, Jung-Hwan;Jun, Houngbae;Kim, Sungkyoon
    • Journal of Environmental Health Sciences
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    • v.47 no.2
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    • pp.111-122
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    • 2021
  • Objectives: There was a judgment of acquittal for the manufacturer SK Chemical and the vendor Aekyung regarding humidifier disinfectant (HD) containing 5-chloro-2-methylisothiazol-3(2H)-one/2-methylisothiazol-3(2H)-one (CMIT/MIT). The rationale used in this judgement is discussed here in the light of scientific consideration. Methods: The sentencing document for the judgements was obtained from the Korea Supreme Court Service. In particular, the judgements made by the court related to the risk of HD and external and internal exposure to CMIT/MIT are discussed based on scientific evidence. Results: Rendering a determination in a criminal trial of insufficient evidence of causation, the court dismissed the prosecution's motion that humidifier disinfectant-associated lung injuries (HDLI) and asthma were associated with the utilization of these products. However, CMIT/MIT, a strong sensitizing and corrosive substance, has been reported to be associated with brain toxicity, allergic contact dermatitis, and asthma. Furthermore, the judgment did not consider total consumption amounts or the cumulative dose of CMIT/MIT in the humidifier. Lastly, there are several cases supporting the fact that exposure to water-soluble substances including CMIT/MIT can cause lower respiratory tract diseases. In addition to cases of asthma among the workers exposed to CMIT/MIT, we identified lung injury victims who were exposed to HDs exclusively containing CMIT/MIT. Conclusions: We conclude that there is sufficient evidence supporting the assertion that HDs containing CMIT/MIT cause lung injuries, including asthma, contrary to the court's judgement.

A study on rationalized values of deoxygenation coefficient for stream quality modelling in the Hwangguji stream (수질모의시 적정 탈산소계수 선정을 위한 연구 - 황구지천을 대상으로 -)

  • Noh, Huiseong;Ahn, Taejin
    • Journal of Wetlands Research
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    • v.21 no.1
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    • pp.77-83
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    • 2019
  • Stream water qualities have been predicted in the year 2002 and 2014 through providing the Hwangguji Stream Rectification Plan. However, the reliability of result for predicted water quality was relatively lower by applying conventional values of the parameters in model. In this study deoxygenation coefficients between Sema bridge(HGJ2) and Sujik bridge(HGJ3) have been evaluated based on the observed data of water quality and travelling time to compare with the applied value of coefficients in predicting water quality model. The values of deoxygenation coefficient $0.078day^{-1}{\sim}0.748day^{-1}$ for normal period and $0.053day^{-1}{\sim}0.505day^{-1}$ for drought period have been calculated based of observed data between Sema bridge and Sujik bridge. The values of coefficients $0.02day^{-1}{\sim}3.4day^{-1}$ have been applied in predicting water quality model in the year 2002 and $0.043day^{-1}$ 2014. Thus, the simulated results of stream water quality were better than the observed data in 2002, and worse in 2014. It has shown that values of deoxygenation coefficient should be properly estimated based on observed data to predict proper stream water quality by model.

Construction of Mine Geospatial Information by Total Station and 3D Laser Scanner (토털스테이션과 3D 레이저 스캐너에 의한 광산공간정보 구축)

  • Park, Joon-Kyu;Lee, Keun-Wang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.3
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    • pp.520-525
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    • 2019
  • Mines are an important infrastructure for securing resources, but safety problems can arise in the course of operation. Recently, the mining process is very complicated due to the large scale and mechanization. Therefore, it is necessary to construct accurate geospatial information on mine for systematic and safe mine operation. The geospatial information construction using the existing total station has a disadvantage that a lot of work time is required because the target must be collimated and measured. In this study, the data of the mines were acquired with the total station and the 3D laser scanner, and the mine spatial information was constructed by using the shape based registration method. By using the static scanner data of some area applying the reference point surveying result of the total station, it was possible to construct the accurate result on the wide area acquired by the mobile scanner effectively. Also, the accuracy of the constructed geospatial information was evaluated and the deviation of mean 0.083m was shown. Point cloud products constructed through the research can contribute to the efficiency improvement of mine management by enabling quantitative analysis such as visualization of mine shape, distance, area and slope, and automation of drawing creation for cross section shape.

Anti-obesity Effects and Safety of the Mixture of Herbal Extracts in 3T3-L1 Cells and HR-1 Mice Fed a High Fat Diet (3T3-L1 지방전구세포와 고지방 식이로 유도된 비만 HR-1 마우스 피부에 도포한 한약 추출 복합물의 항비만 효과 및 안전성 평가)

  • Jeong, Eui Seon;Park, So Yi;Lee, Ki Hoon;Na, Ju Ryun;Kim, Jin Seok;Park, Kyung Mok;Kim, Sunoh
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.32 no.6
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    • pp.384-395
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    • 2018
  • The aim of this study was to investigate whether a novel formulation of an herbal extracts has an inhibitory effect on obesity. To determine its anti-obesity effects, we performed anti-obesity-related experiments in vitro and in vivo. Thus, our present study was carried out to evaluate the anti-obesity effect of herbal extracts using a high fat diet (HFD)-induced obese mouse model and 3T3-L1 adipose cells. The effects of each herbal extracts on lipid accumulation in 3T3-L1 cells were examined using Oil Red O staining. Results showed that treatment with each herbal extracts at $10{\sim}100{\mu}g/ml$ had no effect on cell morphology and viability. Without evidence of toxicity, herbal extracts treatment decreased lipid accumulation compared with the untreated adipocytes controls as shown by the lower absorbance of Oil Red O stain. Futhermore, compared with control-differentiated mature adipocytes, each herbal extracts significantly inhibited lipid accumulation in mature 3T3-L1 adipocytes. In the HFD-fed obese mice, body weight, liver weight and white adipose tissue weights were significantly reduced by mixture of herbal extracts administration in mouse skin. Futhermore, we found that mixture of herbal extracts administration suppressed serum triglyceride (TG), and total cholesterol (TCHO) in HFD-induced obese mouse model. The mixture of herbal extracts of permeability was estimated by measuring the transepithelial electrical resistance (TEER) value in pig skin. The optimized formulations of herbal extracts (Test 3 formulation) showed skin permeation. However, test 1 formulation containing essential oil as enhancer showed maximum skin permeation. After confirming the enhanced skin permeability, in vivo studies were performed to assess whether skin irritation potential on the basis of a primary irritation index (PII) in rabbit skin. Reactions were scored for erythema/edema reactions at 24 h, 48 h and 72 h post-application. It was concluded that the test 1 formulation was not irritation (PII = 0). The present study suggests that the test 1 formulation might be of therapeutic interest with respect to the treatment of obesity.

Drainage system for leakage treatment of cement concrete structure in underground (콘크리트 지하구조물 누수 처리를 위한 유도배수시스템)

  • Kim, Dong-Gyou
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.4
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    • pp.573-585
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    • 2019
  • The objective of this study is to propose the drainage system that has been improved the workability, waterproofing and drainage performance to treat the leakage from the cement concrete structures in underground. It is improved that the pipe for conveying ground leak in the existing drainage system had the problem in workability and waterproof. The drainage systems with the improved pipe for conveying ground leak were constructed in conventional concrete lining tunnels to evaluate the workability, waterproofing and drainage. The waterproof and the drainage performance of the drainage system was evaluated by injecting 1,000 ml of red water in the back of the drainage system at 3 weeks, 6 weeks, 9 weeks, 11 weeks, 14 weeks, 17 weeks and 23 weeks. During 6 months of field performance test, the average daily temperature of the tunnel site was measured from $-12.4^{\circ}C$ to $19.7^{\circ}C$. The daily minimum temperature was $-17.2^{\circ}C$ and the daily maximum temperature was $26.7^{\circ}C$. There was no problem in waterproof and drainage performance on the pipe for conveying ground leak and the drainage system during 6 months for field performance test. It is concluded that the improved drainage system can be applied to various cement concrete underground structures where leakage occurs, and has little seasonal effect.

Numerical modelling of Fault Reactivation Experiment at Mont Terri Underground Research Laboratory in Switzerland: DECOVALEX-2019 TASK B (Step 2) (스위스 Mont Terri 지하연구시설 단층 내 유체 주입시험 모델링: 국제공동연구 DECOVALEX-2019 Task B(Step 2))

  • Park, Jung-Wook;Guglielmi, Yves;Graupner, Bastian;Rutqvist, Jonny;Park, Eui-Seob
    • Tunnel and Underground Space
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    • v.29 no.3
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    • pp.197-213
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    • 2019
  • We simulated the fault reactivation experiment conducted at 'Main Fault' intersecting the low permeability clay formations of Mont Terri Underground Research Laboratory in Switzerland using TOUGH-FLAC simulator. The fluid flow along a fault was modelled with solid elements and governed by Darcy's law with the cubic law in TOUGH2, whereas the mechanical behavior of a single fault was represented by creating interface elements between two separating rock blocks in FLAC3D. We formulate the hydro-mechanical coupling relation of hydraulic aperture to consider the elastic fracture opening and failure-induced dilation for reproducing the abrupt changes in injection flow rate and monitoring pressure at fracture opening pressure. A parametric study was conducted to examine the effects of in-situ stress condition and fault deformation and strength parameters and to find the optimal parameter set to reproduce the field observations. In the best matching simulation, the fracture opening pressure and variations of injection flow rate and monitoring pressure showed good agreement with field experiment results, which suggests the capability of the numerical model to reasonably capture the fracture opening and propagation process. The model overestimated the fault displacement in shear direction and the range of reactivated zone, which was attributed to the progressive shear failures along the fault at high injection pressure. In the field experiment results, however, fracture tensile opening seems the dominant mechanism affecting the hydraulic aperture increase.

A Study on the Development of Driving Simulator for Improvement of Unmanned Vehicle Remote Control (무인차량 원격주행제어 신뢰성 향상을 위한 통합 시뮬레이터 구축에 관한 연구)

  • Kang, Tae-Wan;Park, Ki-Hong;Kim, Joon-Won;Kim, Jae-Gwan;Park, Hyun-Chul;Kang, Chang-Keun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.86-94
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    • 2019
  • This paper describes the development of unmanned vehicle remote control system which is configured with steering and accelerating/braking hardware to improve the sense of reality and safety of control. Generally, in these case of the remote control system, a joystick-type device is used for steering and accelerating/braking control of unmanned vehicle in most cases. Other systems have been developing using simple steering wheel, but there is no function of that feedback the feeling of driving situation to users and it mostly doesn't include the accelerating/braking control hardware. The technology of feedback means that a reproducing the feeling of current driving situation through steering and accelerating/braking hardware when driving a vehicle in person. In addition to studying feedback technologies that reduce unfamiliarity in remote control of unmanned vehicles, it is necessary to develop the remote control system with hardware that can improve sense of reality. Therefore, in this study, the reliable remote control system is developed and required system specification is defined for applying force-feedback haptic control technology developed through previous research. The system consists of a steering-wheel module similar to a normal vehicle and an accelerating/braking pedal module with actuators to operate by feedback commands. In addition, the software environment configured by CAN communication to send feedback commands to each modules. To verify the reliability of the remote control system, the force-feedback haptic control algorithms developed through previous research were applied, to assess the behavior of the algorithms in each situation.

Detecting and Avoiding Dangerous Area for UAVs Using Public Big Data (공공 빅데이터를 이용한 UAV 위험구역검출 및 회피방법)

  • Park, Kyung Seok;Kim, Min Jun;Kim, Sung Ho
    • KIPS Transactions on Software and Data Engineering
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    • v.8 no.6
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    • pp.243-250
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    • 2019
  • Because of a moving UAV has a lot of potential/kinetic energy, if the UAV falls to the ground, it may have a lot of impact. Because this can lead to human casualities, in this paper, the population density area on the UAV flight path is defined as a dangerous area. The conventional UAV path flight was a passive form in which a UAV moved in accordance with a path preset by a user before the flight. Some UAVs include safety features such as a obstacle avoidance system during flight. Still, it is difficult to respond to changes in the real-time flight environment. Using public Big Data for UAV path flight can improve response to real-time flight environment changes by enabling detection of dangerous areas and avoidance of the areas. Therefore, in this paper, we propose a method to detect and avoid dangerous areas for UAVs by utilizing the Big Data collected in real-time. If the routh is designated according to the destination by the proposed method, the dangerous area is determined in real-time and the flight is made to the optimal bypass path. In further research, we will study ways to increase the quality satisfaction of the images acquired by flying under the avoidance flight plan.