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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Safety
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Journal DOI :
The Korean Society Safety
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Volume & Issues
Volume 25, Issue 6 - Dec 2010
Volume 25, Issue 5 - Oct 2010
Volume 25, Issue 4 - Aug 2010
Volume 25, Issue 3 - Jun 2010
Volume 25, Issue 2 - Apr 2010
Volume 25, Issue 1 - Feb 2010
Selecting the target year
Effects of Pressure Tapping Conditions on Flow Rate Measurement of Triangular Separate Bar Differential Pressure Flow Meter
Lee, Choong-Hoon ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 1~6
Flow characteristics of differential pressure flow meters which have a shape of triangular separate bar (TSB) was investigated according to the machining conditions in pressure tapping holes. Diameter of the pressure taping holes is either 1.0 mm or 1.5 mm. Also, number of the pressure tapping holes are drilled either 9 or 17. The mass flow rate of the TSB flow meters are calibrated with a laminar flow meter by connecting them in line. The mass flow rate in the TSB flow meters are plotted with a non-dimensional parameter H which includes the gas temperature, exhaust gas pressure and differential pressure at the flow meters. An empirical correlation between the mass flow rate at the TSB flow meter and the non-dimensional parameter H was obtained. The empirical correlation showed highly linear relationship between the mass flow rate and the non-dimensional parameter H. The hole size of the pressure tapping holes has a bigger effect on the flow rate than the number of the tapping holes.
A Study on the Measurement of Crack Length of Pipe Specimen Using Image Processing
Kang, Min-Sung ; Koo, Jae-Mean ; Seok, Chang-Sung ; Huh, Yong ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 7~11
Difficulties associated with full-scale pipe tests are rather obvious. That is, it is not only difficult to perform them but also very expensive and it requires lots of experience. And the process of the fracture test for the pipe specimen is very difficult and complicated. Because the pipe specimen, the test jig and the test equipment are very large and heavy, it requires lots of costs and times. In this study, to easily perform the fracture toughness test for a pipe specimen, load line displacement data was obtained using the image processing method.
Numerical Study of Interaction between Hydrogen and Hydrocarbon Flames
Oh, Chang-Bo ; Lee, Eui-Ju ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 12~17
Numerical simulations were performed for the prediction of the flame structure during the interaction between hydrogen and hydrocarbon flames. A counterflow flow geometry was introduced to establish the interacting two flames. Methane was used as a representative hydrocarbon fuel in this study. A well-known numerical code for the counterflow flame, OPPDIF, was used for the simulations. The detailed chemistry was adopted to predict the flame structure reasonably. The interaction of two one-dimensional premixed flames established in counterflow burner was investigated with the global strain rate and velocity ratio. It was found that the maximum temperature located near the methane flame surface while the heat release rate of methane was lower than hydrogen flame. The flame thickness become narrow with increasing the velocity ratio while the global strain rate was fixed. The local strain rate and heat release rate at the methane flame surface were correlated with the global strain rate, while those at the hydrogen flame were not correlated with the global strain rate. However, the maximum temperature of the interacting flames was correlated with the global strain rate.
Analysis of Fire Accident on Power Line for DC Electric Traction Vehicles
Song, Jae-Yong ; Cho, Young-Jin ; Nam, Jung-Woo ; Kim, Jin-Pyo ; Park, Nam-Kyu ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 18~23
This paper describes a cause of fire accidents on power system fire DC electric traction vehicles. We investigated fire scene of power line for DC electric traction vehicles. From analysis results, the cause of fire on power line turned out line to ground fault between a feeder of electric power services(pantagraph) and DC electric traction vehicle roof. Fire accident of DC electric traction vehicles be assumed that electric sparks had been produced between the pantagraph and the power line conductor by repetitively making contact and separation, maybe if some material like branches get in between connecting rod it makes progress line to ground fault. ZnO arresters are widely used to protect DC electric traction vehicles against overvoltages caused by lightning or switching surges. However, the arresters are deteriorated by commercial overvoltages and/or lightning one. The deteriorated arresters could lead power failures, such as line to ground fault by a thermal runaway resulting from the increases in leakage current even in a nominal power system voltage. Finally, the power failures would be causative of the fire accident.
A Study on Battery Charger Reliability Improvement of Nuclear Power Plants DC Distribution System
Lim, Hyuk-Soon ; Kim, Doo-Hyun ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 24~28
The nuclear power Plant onsite AC electrical power sources are required to supply power to the engineering safety facility buses if the offsite power source is lost. Typically, Diesel Generators are used as the onsite power source. The 125 VAC buses are part of the onsite Class 1E AC and DC electrical power distribution system. The DC power distribution system ensure the availability of DC electrical power for system required to shutdown the reactor and maintain it in a safety condition after an anticipated operational occurrence or a postulated Design Base Accident. Recently, onsite DC power supply system trip occurs the loss of system function. To obtain the performance such as reliability and availability, we analyzed the cause of battery charger trip and described the improvement of DC power supply system reliability. Finally, we provide reliability performance criteria of charger in order to ensure the probabilistic goals for the safety of the nuclear power plants.
Development of Monitoring Program for Detecting Current and Voltage Signals for Series Arc
Kim, Doo-Hyun ; Park, Jong-Young ; Kim, Sung-Chul ; Lee, Jong-Ho ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 29~34
This paper is aimed to develop monitoring software for detecting the characteristics of current and voltage signals for series arc on electric wire. In order to attain this purpose, the characteristics of series arc were analyzed by the current and voltage signals on electric wire which were installed, and also analyzed by the changes of RMS, instantaneous of waveform value in time domain and THD in frequency domain. Monitoring program which analyze the signal was developed by Labview which can analyze in time domain and frequency domain, and save data. Experimental setup for detecting verification of monitoring program was composed loads of a lamp, an electric heater and an electric fan loads which were usually using. Measurement points for detecting verification of monitoring program were selected at both the panel board and the arc generator at the same time. As results of the experiments by monitoring program, the arc current waveform showed the same characteristic in all measurement points of all load. But the arc voltage waveform was different in each measurement point. When arc occurred, the THD of current value increased above 20%. The results of this study will be effectively used in developing the preventive system of electric fire by series arc.
Prediction of Upper Explosion Limits(UEL) by Measurement of Upper Flash Point Using Setaflash Apparatus for n-Alcohols
Ha, Dong-Myeong ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 35~40
Explosion limit and flash point are the major combustion properties used to determine the fire and explosion hazards of the flammable substances. In this study, in order to predict upper explosion limits(UEL), the upper flash point of n-alcohols were measured under the VLE(vapor-liquid equilibrium) state by using Setaflash closed cup tester(ASTM D3278). The UELs calculated by Antoine equation using the experimental upper flash point are usually lower than the several reported UELs. From the given results, using the proposed experimental and predicted method, it is possible to research the upper explosion limits of the other flammable substances.
A Experimental Study on the Construction Material Using the Circulation Resources
Hong, Se-Hwa ; Son, Ki-Sang ; Choi, Jea-Nam ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 41~46
This is to show some basic data for introducing both circulated aggregate and recycled powder producing waste concrete. Standard-mixing design for 24MPa has been basically used and added and replaced normal aggregate with recycled powder made of waste concrete. In addition, polycarboxylate high-range water reducing agent has been used because recycled powder is missing adhesive strength and it is not compare with cement's adhesive strength. Compressive strength with powder mixture of 2%, 4%, 6%, 8%, and 10% has been decreased down to 80% of normal concrete material strength without recycled powder mixture. This result has same decreasing proportion to tensile strength of the material. Resistant capacity change of beam varying with recycled powder mixture has been decreased down to 60% of normal concrete bean capacity, while there are 80% decrease of material strength. But strength and capacity change has same consistent decrease ratio. It is found that recycled powder with approximately 15% unit concrete volume can be replaced with cement in reasonable admixture mixing condition.
RBSN Analysis Model of Asphalt Pavement Retrofitted with Civil Fiber
Han, Sang-Hoon ; Kwak, So-Shin ; Kwon, Yong-Kil ; Hong, Ki-Nam ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 47~54
This paper presents a simple and efficient two-dimensional rigid-body-spring network model able to accurately estimate the fractural behavior of civil fiber reinforced pavements. The proposed rigid-body-spring network model, denoted as RBSN model, considers civil fiber reinforcing materials using the beam elements and link spring elements. The RBSN method is able to model collapse due to asphalt crushing and civil fiber slip. The RBSN model is used to predict the applied load-midspan deflection response of civil fiber retrofitted asphalt specimen subjected to the three-point bending. Numerical simulations and experimental measurements are compared to based on tests available in the literature. The numerically simulated responses agree significantly with the corresponding experimental results until the maximum load. However, It should be mentioned that, in order to more accurately predict the postpeak flexural behavior of the civil fiber retrofitted asphalt pavement, development of the advanced model to simulate the slip relationship between civil fiber and asphalt is required.
Influence of Sampling and Preparation Method on Stress-Strain Behavior of Weathered Granite Soils
Cho, Wan-Jei ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 55~64
Since various weathered soils are encountered in many domestic construction sites, it is necessary to estimate characteristics of natural weathered soils. However, the remolded sample of weathered soils are commonly used to estimate their characteristics because it is very difficult to sample weathered soils in undisturbed states. However, it is well known that the behavior of remolded sample is different from that of the undisturbed sample particularly in the dynamic response, because the particle structure of undisturbed sample maintains its original structure from the mother rock. Thus, to evaluate the influence of sampling method and preparation method on stress-strain behavior, the resonant column tests were performed on the block, tube samples, remolded samples with static compression and remolded samples with tamping of the weathered granite soils. The shear modulus of the remolded sample with tamping is larger than the other samples presumably due to the high tamping pressure enough to induce particle breakage. The tube samples show larger damping ratios than other samples. Furthermore, one-dimensional ground response analysis was performed to compare the results qualitatively.
A Study on the Hazardous Area Management using the RTLS
Ock, Young-Seok ; Lee, Chang-Hee ; Lee, Jong-Bin ; Chang, Seong-Rok ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 65~70
Interest to the RTLS is increasing recently, and the RTLS is used in various fields. It is one of applications for locating and tracking using RFID tags which are attached to something like container, pallet, or all thing. In this study, a RTLS system was developed for efficient safe management in chemical industry. This system could manage dangerous substance and a personal history regarding entry. Detailed results of this study are as follows: (1) Through RTLS entry management system which is developed this study, the events along a movement of dangerous substances and the person in charge could be grasped and recorded. (2) A user, goods and a warehouse could be managed and monitored efficiently as using the developed RTLS history system. (3) RTLS system will contribute to efficient safety management of the chemical industry. Besides, RTLS system might be applied to the other industries like shipbuilding and car industry.
A Study on the Job Stress and the Work Ability of Workers in the Shipbuilding Industry
Lee, Yu-Jeong ; Chang, Seong-Rok ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 71~77
According to the Korea National Statistical Office data in 2008, the population over ages of 65 years would possess to 10.7% whole population of Korea in 2009 denoting Korea is already in the aging society. In addition, the office also expected that Korea would enter in the aged population over 65 years: 14.3% and post-aged 20.8% society in 2019 and 2026 respectively, and which suggests that an averaged age of workers in Korean industries may increase rapidly in future. The main purpose of this study is to assess the work ability and the job stress of each age group in order to identity the influential factors on those items. To this end, Questionnaires about work ability and job stress were distributed to practitioners in shipbuilding industry and statistical analysis was performed to assess work ability and the job stress based on the responses from the practitioners.
A Study on the Variations of Runing Speed Characteristics by Automated Speed Enforcement System
Kim, Wan-Ki ; Ryu, Boo-Hyung ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 78~83
An installation of automated speed enforcement system(ASES) was known for traffic safety and accident preventive effects that traffic characteristics transmute by speed distribution stabilizing. This study is verified the variations of average speed, 85% speed, speed distribution and dispersion as traffic characteristics depend on enforcement system influences in the road. We tested selected 5 areas. By and large, it has a little differences depend on road geometric structure and traffic environment but that is not too much. After all, after automated speed enforcement system installed in all of test areas, average speed, 85% accumulated speed, speed distribution and dispersion characteristics were declined and equalized. The speed dispersion was smaller than before installed the ASES. The speed dispersion value of each case that is the limited speed has been 70Km/h, 80Km/h at flat and straight, 80Km/h at downhill and straight or downhill and left-curved area was 77.3%, 65.2%, 68.7% and 54.1%. Each of the data was declined. We could analyze that average speed distributed depletion factor was declined rapidly by 66.3% in test area.
A Development of the Accident Prediction Models Considering Compound Curves
Lee, Soo-Il ; Won, Jai-Mu ; Im, Ji-Hee ; Lee, Jae-Myung ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 84~88
The main point of this study is to find ways to prevent accidents at complex linear sections in advance by improving geometric structure elements that can be considered from the designing stage. Complex linear roads are consisted of sections where straight sections connect with curved sections or sections where curved sections connect with curved sections with relatively high possibility of accidents and accidents can be reduced through improving designing elements in these sections. Therefore, this study aims to develop accident forecasting model in complex linear roads and to clarify major elements affecting traffic accidents. The results of analysis showed that the groups are divided into a group less than 355m based on curve radius of 355m, a group whose curve radius exceeds 355m and a group whose incline exceeds -0.79 and a group whose curve radius is below 355m and incline exceeds -0.79 for straight section + curved section, and for curved section + curved section, it is divided into a group whose first curved section is less than 410m based on curve radius of 410m and the first curve is turning right and a group exceeding 410m and the first curve is turning left. The major variables common in 2 models are front curve radius and curve types(left, right), road surfaces, weather.
Safety Performance Models of Improvement Projects of Frequent Traffic Accident Locations
Park, Byung-Ho ; Park, Gil-Su ; Kim, Tae-Young ;
Journal of the Korean Society of Safety , volume 25, issue 2, 2010, Pages 89~94
This study deals with the traffic accident according to the improvement projects of frequent accident locations. The objective is to analyze the impact of improvements on the accident reduction. In pursuing the above, the study gives the particular attentions to developing the models based on the data of 70 intersections improved. The main results analyzed are as follows. First, 4 multiple linear regression accident models(total, side right-angle, rear end and side stripe accident) which were statistically significant were developed. Second, total accidents reduction by sight-distance and turning traffic flow improvements, side right-angle by sight-distance, over-speed and lane operation, rear end by turning traffic flow, signal and lane operation, and side stripe by traffic impedance improvements were analyzed. Finally, the above 4 models were evaluated to be statically significant through the correlation analysis and pair-sample t-test.