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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
Development of P-PIE Program for Evaluating Failure Probability of Pipes in Nuclear Power Plants
Park, Jai-Hak ; Lee, Jae-Bong ; Choi, Young-Hwan ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 1~8
P-PIE program is developed for evaluating failure probability of pipes in nuclear power plants based on the existing PRAISE program. In the program, crack growth due to fatigue loading and stress corrosion can be considered and the probability of fracture or leakage of pipes can be calculated. Crack growth simulation is performed based on stress intensity factor and a damage parameter and failure of a pipe is determined based on J integral or net section yielding. Using the developed program the failure probabilities of tubes in a domestic nuclear power is obtained and discussed.
The Characteristics of Soot at the Post-Flame Region in Jet Diffusion Flames Added Carbon Dioxide
Ji, Jung-Hoon ; Lee, Eui-Ju ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 9~13
An experimental study for characteristics of soot were conducted at the post-flame region in jet diffusion flames, where carbon dioxide was used as additives in oxidizer stream. Light-extinction method was performed using He-Ne laser with wave length at 632.8nm for the measurement of relative soot density and soot volume fraction with dimensionless extinction coefficient,
and mass specific extinction coefficient,
. To increase of resolution, laser light was modified for sheet-form using concave, convex lenses and slit. C/H ratio was introduced for quantitative analysis of soot growth which is expressed by carbonization and dehydrogen. Also transmission electron microscopy(TEM) was used for observation of morphological shape. The results show that the relative soot density in the post-flame region was lower when carbon dioxide was added in oxidizer stream because of reduction of flame temperature.
Evaluation of Shear Strength of a Miniature Lead-free Single Solder Ball Joint
Joo, Se-Min ; Kim, Ho-Kyung ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 14~21
A miniature single solder ball joint is designed to mimic the actual solder joints used in the micro-electric industries. Shear tests were conducted to evaluate the mechanical behavior of miniature single solder joints at intermediate strain rates from
at room temperature. The shear fracture strength of the present solder ball joints generally increased with increasing shear strain rate, ranging from 32 to 51MPa. This behavior is affected by the sensitivity of bulk solder strength to strain rate. Shear fracture mode changed from brittle to partial ductile (failure inside the bulk solder) with an increase of shear speed. The unloading shear fracture toughness is generally consistent with the measure of the amount of bulk solder on the fractured surface.
Characteristics of Flow Coefficients in an Engine Cylinder Head with a Quasi-steady Flow Condition by Continuous Variation of the Valve Lift
Oh, Dae-San ; Lee, Choong-Hoon ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 22~27
Flow Coefficients of intake port in an engine cylinder head were measured by a newly designed flow rig. In measuring the flow coefficient with traditional method, the valve lift was manually varied by technician with adjusting a micrometer which is directly connected to the intake valve of the cylinder head. The cam shaft of the cylinder head is directly rotated by a step motor and the valve lift was automatically varied with cam shaft profile in the newly designed flow rig. The measurement of the flow coefficient was automated by rotating the cam shaft with the step motor. Automatic measurement of the flow coefficient could be safely measured by separating a technician from the noise and vibration of the traditional flow rig. Also, the automatic measurement of the flow coefficient reduce the measurement time and provide meaningful statistical data.
Corrosion and Corrosion Fatigue Characteristics of Artificially Sensitized STS 304
Han, Ji-Won ; Bae, Dong-Ho ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 28~33
Stainless steel is useful material for various industrial facilities such as the nuclear and steam power plant and the heavy chemical industry due to its good corrosion resistance and mechanical properties. However, it has also a large problem that is sensitized in the welding process and its corrosion resistance and mechanical properties decreases by sensitization. Thus, corrosion and corrosion fatigue characteristics of artificially sensitized austenitic STS304 were investigated through the EPR test and corrosion fatigue test. Obtained results are as follows: 1) According to the sensitizing period increase, Cr deficiency layer is linearly expanded. 2) Degree of sensitization(Ia/Ir) proportionally increased with sensitizing period. However, after 4hrs, it showed constant value. 3) Cr-carbide(
) in the grain boundary increased as sensitizing period increases until six hours. 4) corrosion fatigue strength of sensitized STS304 were remarkably reduced compare to non-sensitized ones.
A Quantitative Risk Analysis of Related to Tower Crane Using the FMEA
Shim, Kyu-Hyung ; Rie, Dong-Ho ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 34~39
The purpose of this study is to suggest objective evaluation model as a plan to utilize as opportunity in establishing judgment standard of mutual inspection criteria and to upgrade inspection ability by reviewing and analyzing level of danger and importance in advance based on inspection results of inspection institutions regarding tower cranes used in construction fields. Tower crane is a mechanical device transporting construction supplies and heavy materials to places over 20~150M high from the ground for the period ranging from a short time of 2~3 months to two years after being installed in construction sites in vicinity of buildings or structures and is an important facility indispensable for construction sites. However, since use period after installation is short and professional technical ability of technicians working on-site about of tower crane is poor, systematic and quantitative safety management is not carried out As a part of researches on procedure of RBI(Risk Based Inspection) possible to apply to Knowledge Based System based on knowledge and experiences of experts as well as to tower cranes for solving these problems, quantitative RPN(Risk Priority Number) was applied to RPN utilizing technique of FMEA(Failure Mode and Effect Analyses). When general RBI 80/20 Rule was applied parts with high level of risks were found out as wire rope, hoist up/down safety device, reduction gear, and etc. However, since there are still many insufficient parts as risk analyses of tower crane were not established, it is necessary for experts with sufficient experiences and knowledge to supplement active RBI techniques and continuous researches on tower cranes by sharing and setting up data base of important information with this study as a starting point.
A Study on Hand Speed Constant to Calculate Safe Distance of Press Protective Device
Lee, Keun-Oh ; Kim, Jong-Hyun ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 40~46
To protect press operator from the after-reach hazard, current Ministry of Labor Notification(MOLN) requires the use of a formula for calculating the safe distance away from the point of operation for locating press protective devices, Two Hand Control Devices(THCD) and Active Opto-Electronic Protective Devices(AOPD), on a power press. This formula is based on a same hand speed constant of 160cm/s. While EN standards use different hand speed constant for THCD and AOPD respectively. The objective of this study is to compare two guidelines on the hand speed constant published by MOLN and EN 692, also to propose a proper hand speed constant and validate it experimentally. As a experimental result, it could be known that hand speed constant of Ministry of Labor Notification should be improved as that of EN standards.
A Study on the Accident Rate Forecasting and Estimated Zero Accident Time in the Transportation, Storage, and Telecommunication Divisions
Kang, Young-Sig ; Kim, Tae-Gu ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 47~52
Many industrial accidents have occurred over the years in the manufacturing and construction industries in Korea. However, as the service industry has increased continuously, the share of the accident rate in the service industry was 39.07% in 2009, while the manufacturing industry share was 33.73%. The service industry share overtook the manufacturing industry share for the first time. Therefore, this research considers prevention of industrial accidents in the service industry as well as manufacturing and construction industries. This paper describes a procedure and a method to estimate efficient accident rate forecasting and estimated zero accident time in the service industry in order to prevent industrial accidents in the transportation, storage, and telecommunication divisions. This paper proposes a model using an analytical function for the sake of very efficient accident rate forecasting. Accordingly, this paper has develops a program for accident rate forecasting, zero accident time estimating, and calculation of achievement probability through MFC (Microsoft Foundation Class) software Visual Studio 2008 in the transportation, storage, and telecommunication divisions. In results of this paper, ARIMA (Auto Regressive Integrating Moving Average) is regarded as a very efficient forecasting model for the transportation, storage, and telecommunication division. In testing this model, value minimizing the Sum of Square Errors (SSE) was calculated as 0.2532. Finally the results of this paper are sure to help establish easy accident rate forecasting and strategy or method of zero accident time in the service industry for prevention of industrial accidents.
Effect of Stress Concentration Factors on the Fatigue Evaluation of the Direct Vessel Injection Nozzle
Kim, Tae-Soon ; Lee, Jae-Gon ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 53~59
A fatigue damage caused by cyclic load is considered as one of the important failure mechanisms that threaten the integrity of structures and components in a nuclear power plant. In ASME code section III NB, the fatigue analysis procedure and standard S-N curves for the class 1 components are described and these criteria should be met at the design step of components. As the current ASME S-N curves are based on the very conservative assumptions such as a local stress concentration effect, immoderate transient frequencies and a constant Young's modulus, however, they can not precisely address the fatigue behavior of components. In order to find out the technical solution for these problems, a number of researches and discussion have been carried out continuously at home and abroad over the decades. In this study, detailed fatigue analyses for DVI nozzle with various mesh density of finite elements were performed to evaluate effect of stress concentration factors on the fatigue analysis procedure and the excessive conservatism of stress concentration factors are confirmed through the analysis results.
The Development of the Slope Monitoring System(SMS) of the Tower Crane
Shin, Woon-Chul ; Hong, Yong-Soo ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 60~64
The purpose of this study if to prevent dangerous accident of the overthrow of the tower crane in summer's hurricane. We develop the SMS in order to give automatic alarm system to operator within the dangerous range and to give a information of the exactly slope in the real time. The slope value of the tower crane is compose of direction, pitch by the front and rear, roll by the right and left and synthesis by the its pitch and roll. Especially, the synthesis eliminate the effect of the wall tie or wire bracing. So, this value should correctly indicate the actual slope. In this study, more applying field test should be applied with the SMS. In the future, a more measurement device can be applied to, and be able to feed more alarm criteria for the review of the risk in the field.
Experimental Study on Slip Characteristics of Floor Surface Roughness and Slider Materials
Kim, Jung-Soo ; Park, Jea-Suk ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 65~69
This paper presented an experimental study of slip resistance characteristics of shoes and floor surface contact with special focus on the effect of surface roughness, outsole material and mechanical abrasion. The factors that affected the results of slip resistances were investigated for four kinds of rubbers and five kinds of floor samples using the VIT(English XL) tribometer. The slip resistance was observed to increase gradually with increasing roughness for five kinds of floor roughness. In the higher surface roughness (larger than
), the slip resistance increased more rapidly and exceeded safety criteria at
. The slip resistance was observed to decrease with increasing hardness of outsole, except for butylenes rubber, which seemed to show the material property. The slip resistance decreased with number of trials. In the first several times(5 or 6 trial), the slip resistance decreased more rapidly, whereafter it approached gradually constant value. The slip resistance of surfaces has generally been shown to increase with floor surface roughness and to decrease with hardness of outsole and number of trials under the wet condition.
Work limit Load Efficiency According to Splicing Method for Hand Spliced Wirerope Sling
Park, Jae-Suk ; Han, Kyoung-Hun ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 70~74
For each strand of wirerope sling, the international standards, ISO-8794, EN-13414 specify that the splice shall have five series of load carrying tucks. At least three of the load carrying tucks shall be made with the whole strand. And, the breaking force of the splice shall not be less than 70% or 80% of that of rope. But, There are no prescriptions for splicing types against different efficiency of each splicing type being used many workplace. In this study, analysis the work limit load efficiency according to variation of number of tucks and splicing types by experimental method As a result, the number of tucks 3+2 had the highest breaking efficiency.
Development of Remote Supervision System for Guam Lamps by Way of Leakage Current(Igr) Detection Method
Choi, Myeong-Il ; Kim, Young-Seok ; Kim, Chong-Min ; Bang, Sun-Bae ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 75~80
The present study presented the implementation of a remote control/supervision system for guard lamps used in public illumination with little endeavor by far for safe management, which makes possible to supervise the state and to control the functions remotely including electric safety elements. Especially, the developed system adopts the measurement algorithm for detecting resistive leakage current(Igr) flowing based on the phase difference checkable for sensing at a monitor, being allowable for monitoring at MMI and transmitter for data transmittance. To verify reliability about the algorithm to accurately detect Igr leakage current, the laboratory-based functional test was performed.
Research on Dielectric Characteristics of Environmental-Friendly Vegetable Insulation Oil for the Pole Transformer
Kwag, Dong-Soon ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 81~85
In recent years, environmental concerns have been raised on the use of poorly biodegradable fluids in electrical apparatus in regions where spills from leaks and equipment failure could contaminate the surroundings. The vegetable insulation oils are highly biodegradable, have negligible effect on the environment, human health and ecosystem. Therefore, to assure their safe use in electrical power systems, it may require some processing and modification to improve some of their physical, chemical, thermal and electrical properties. This paper provides a comparative results of the electrical breakdown properties of several vegetable insulation oils and mineral oil to use as dielectric fluid in environmental-friendly pole transformer. Also, the electrical breakdown property of the Nomex and kraft insulation papers in vegetable insulation oil is examined.
Analysis of the Damage Patterns and Metal Structure of 3 Phase Mold Transformers to which Interlayer Short-circuits have Occurred
Choi, Chung-Seog ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 86~91
The purpose of this study is to analyze the damage patterns and metal structure of 3 phase mold transformers collected from places where accidents have occurred. Compared to an oil-immersed transformer, a mold transformer has the advantage of requiring a smaller installation area and can be kept clean, while its disadvantages include the fact that abnormal symptoms of an accident are difficult to discover and its repair is impossible. The capacity of the mold transformers collected from places where accidents have occurred was 200kVA with primary voltages being F23,900V, R22,900V, 21,900V, 20,900V, 19,900V, etc., as well as secondary voltages being 380V, 220V, etc. It was found from the analysis on the diffusion of combustion in the damaged mold transformers that fire occurred first inside the U-phase primary winding and that carbonization and heat were diffused to V-phase and W-phase in V-pattern. In addition, from the analysis on the cross-sectional structure of the metal of the melted high voltage winding using a metallurgical microscope, it was found that the boundary surface, voids, and columnar structure were formed when an interlayer short-circuit had occurred Therefore, even though it is not possible to find the cause for the occurrence of an interlayer short-circuit at the inner side of the primary winding, it is thought that, due to the thermal energy generated when the short-circuit occurred, the heat source was diffused to the upper side and outside, causing a secondary accident.
A Study on Thermal Characteristics of Biodiesel
Bae, Byong-Mok ; Lim, Woo-Sub ; SaKong, Seong-Ho ; Mok, Yun-Soo ; Choi, Jae-Wook ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 92~97
A study is conducted on thermal characteristics of biodiesel which is already being produced in many countries because of its stable supply of energy in non oil-producing countries and economical benefits against increasing oil price, and environment conservation. So biodiesel has been used as important energy source in the fuel fields and a mount of production has increased year by year. Therefore, it is very important to find out the thermal characteristics of biodiesel for ignition temperature, maximum pressure and thermal behavior. The purpose of this study is to compare on thermal characteristics of biodiesel, petroleum diesel and those mixtures. Also, the main study was performed by flash point testers and modified closed type of pressure vessel test (MCPVT). Based on the data of flash point and MCPVT, the ignition temperature and the maximum pressure of biodiesel was
and 40.1bar, and petroleum diesel was
A Study on the Optimal Installation Technology of LPG Storage Tank through Taguchi Method
Leem, Sa-Hwan ; Huh, Yong-Jeong ; Paek, Seung-Cheol ; Lee, Jong-Rark ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 98~102
LPG (Liquefied Petroleum Gas) vehicles in metropolitan area are being applied to improve air quality and have been proven effective for the reduction of air pollutant. In addition, the demand of gas as an eco-friendly energy source has being increased. With the LPG filling station is also increasing every year. These gas stations are required to install the securest storage tank because of possibility of causing huge loss of life and property. Therefore, in this paper, underground containment type is proposed as installation of the LPG storage tank using Taguchi method, which is considered to be more safe, economical, efficient, easy checking and simple construction method than any other. If leakage, economics, real estate utilization rate, safety, easy to check, simple construct about above ground, buried underground and underground containment storage tank are analyzed by Taguchi method, real estate utilization rate, economic and safety in turn are improved. Therefore, the underground containment storage tank is a optimal installation technology.
An Experimental Investigation on Fire Characteristics of Light Oil & Methanol for Spilled Surface
Lee, Jung-Yon ; Jung, Ki-Chang ; Kim, Hong ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 103~108
In this study, tank truck incidents of road transport of hazardous materials to experimental investigated the potential fire hazard. Real scale fire was to perform experiments for on this qualitative and quantitative data collection and analysis. Particularly affected by radiant heat from the flames caused and damage estimates range investigated accordingly. Flame temperature, internal temperature of tank and emitted radiation from the flames was investigated. The flame of light oil spill caused a fire at a temperature of about
high in comparison with the methanol by combustion of diesel and methanol, according to the difference, the flame duration changes varies depending on the Burning rate, amount of radiant heat flux from light oil fire was 4 times increases compared with fire of methanol. Depending on spill locations(kinds of road surfaces, absorbing rate) and the longer the duration of the flame important factors for the internal temperature of tank truck rise was found. Dirt roads than paved road accident in a fire caused by leakage of hazardous was could the higher the damaged. Therefor, Fire suppression activities should be required in particular to be around.
Extinguishing of Oil Fire by Water Mist Suppression System Using Compressed Inert Gas
Shin, Chang-Sub ; Jeon, Go-Un ; Kim, Ki-Whan ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 109~114
Water mist fire suppression system is environmental system and needs a flange pump to jet water. In this research, high pressure Nitrogen cylinder is used as a pressurizing source instead of flange pump, and also we tried to find the possibility of using compressed Nitrogen as a fire suppression agent. As a result, it was possible to design water mist fire suppression system with Nitrogen cylinder and suppress oil fire effectively. With DK1.58 nozzle, the optimum Nitrogen pressure was 80bar and the pressure was stable during water mist spray. However, jet of Nitrogen was not effective fire suppression agent when it was dually used with water mist because water mist has blown away, and it is efficient way to use compressed Nitrogen as a pressurizing source only.
Optimal Life Cycle Cost Design of a Bridge
Park, Jang-Ho ; Shin, Yung-Seok ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 115~122
The importance of the life cycle cost (LCC) analysis for bridges has been recognized over the last decade. However, it is difficult to predict LCC precisely since the costs occurring throughout the service life of the bridge depend on various parameters such as design, construction, maintenance, and environmental conditions. This paper presents a methodology for the optimal life cycle cost design of a bridge. Total LCC for the service life is calculated as the sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, user cost, and disposal cost. The optimization method is applied to design of a bridge structure with minimal cost, in which the objective function is set to LCC and constraints are formulated on the basis of Korean Bridge Design Code. Initial cost is calculated based on standard costs of the Korea Construction Price Index and damage cost on damage probabilities to consider the uncertainty of load and resistance. Repair and rehabilitation cost is determined using load carrying capacity curves and user cost includes traffic operation costs and time delay costs. The optimal life cycle cost design of a bridge is performed and the effects of parameters are investigated.
A Numerical Analysis of Steel Structures on a Subway Station Fire
Bang, Myung-Seok ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 123~127
A fire disaster is very serious in the closing space like subway station. In this study, the simulation on fire diffusion is performed to get the temperature history curve, which is used for the fire resisting structural analysis. Most of subway stations are built by the reinforced concrete structure, but recently steel structures are selected for the larger space or beauty. Steel structures relatively have more weaknesses against fire, so it is necessary to develop the method for evaluating fire-resisting capacity in this kind of structures. The developed method is applied to the subway station in Daegu city. It shows that the developed method can be used to simulate the fire disaster and to get the temperature history curve and evaluate the safety of steel structures against the fire.
A Proposal of Minimum Steel Ratio Considering Size Effect for Flexural Reinforced Concrete Member
Yoo, Sung-Won ; Her, Yoon ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 128~136
In according with concrete structural design standard, it is common designing flexure reinforcement concrete to induce tension failure. So reinforcing ratio is limited to inducing tension failure. And maximum reinforcing ratio is regulated to protecting concrete compression strength caused by over reinforced building. Minimum reinforcing ratio is also limited in designing standard to protecting brittle failure as extremely using less reinforcing bar. But in minimum reinforcing ratio it is extremely conservative or it is sometimes impossible to induce stable tension-failure because they are depending on yield failure and experienced method and concrete designing standard strength. Therefore the purpose of the present paper is to evaluate the flexural behavior of minimum steel ratio of reinforced concrete of beams and to propose the guide-line of equation of minimum steel ratio by performing static flexural test of 16 beams according to size effect, number of steel, yielding stress of steel, and concrete compressive strength which are presumed effective variables. From experimental results, the equation of minimum steel ratio was newly proposed considered size effect.
Review the Possibility of Replacing the Converted Accident Ratio with the Industrial Accident Compensation Insurance Balance Ratio
Lee, Myeong-Gu ; Jeong, Myeong-Jin ; Kim, Kyu-Dong ; Choi, Eun-Jin ; Park, Seung-Kook ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 137~145
This study examined the possibility of applying the industrial accident insurance balance ratio to the calculation of the converted accident ratio in the credibility assessment of the PQ. Some correlations between the industrial accident insurance balance ratio and the converted accident ratio were found in the general tendency, however, there were no significant correlations between the two in the individual companies. Therefore, this study came to the conclusion that it is not appropriate to directly apply the industrial accident insurance balance ratio to the calculation of the converted accident ratio.
Experimental Study of Extradosed Bridge Anchor System
Kim, Gi-Dong ; Park, Weon-Tae ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 146~154
In this study the experimental results of fatigue specimen for the Strand Stay Cable Assembly of Extadosed bridges is investigated. The fatigue test and tensile experiment is conducted to 6 kinds of specimens. Test specimen OVM250-31 Strand Cable System manufactured by china OVM B-Machinery Co., Ltd, and OVM250-42 Parallel Strand Stay Cable Assembly manufactured by china OVM B-Machinery Co., Ltd, are passed for fatigue test and rupture tensile test. But Test specimen OVM250-42 Parallel Strand Stay Cable Assembly manufactured by korean A-Machinery Co., Ltd, is not passed for fatigue test conducted according to the "Recommendation for Stay Cable Design. The test result are compared to the fatigue criteria of PHI 2001 for cyclic load, and it is concluded that the current korean design code will be needed for representing the fatigue load in Hot Dip Galvanized Strand Stay Cable. It is verified that the new korean specification and quality criteria of Strand Stay Cable and exact experimental applied process will be needed.
Analysis on Durability Performance Enhancement and Economical Efficiency through Chloride Protection for Concrete Structures
Chai, Won-Kyu ; Kim, Seong-Heon ; Son, Young-Hyun ; Park, Ju-Won ; Lee, Cheung-Bin ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 155~160
In this study, detailed assessment for durability performance were performed on the chloride protected concrete structures to investigate the effectiveness of chloride protection. And economical efficiency for the chloride protected concrete structures were studied by LCC(Life Cycle Cost) analysis. In the comparison result of the first section repair time, it was found that the chloride protected concrete structures was economical better than the non-protected concrete structures in the long term. According to the analysis result of the accumulated chloride concentration by used time and chloride ion concentration by depth, it can be seen that the permeation through time from chloride has increased two times in the chloride protected concrete structures.
Fatigue Characteristics of Non Load-Carrying Fillet Welded Joints According to Post-Processing
Hong, Sung-Wook ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 161~168
A series of fatigue tests have been performed on the non-load carrying fillet welded joints in order to quantitatively assess the fatigue characteristics due to the grindings and TIG(Tungsten Inert Gas) welding treatments. From the results of fatigue tests, it has been shown that the fatigue strengths at
load cycles were improved in the case of the grinding sand TIG welding treatments, and we could know that it is satisfying fatigue strength prescribed in fatigue design standard in general. Besides, from the results of fracture mechanics approaches, the geometric shape correction factors were the most dominant factors in the initial fatigue crack growth, but as the fatigue crack develops, the finite plate correction factor were became the most dominant factor, and the fatigue life on non-load carrying fillet welded joints could be relatively exactly estimated by using the relations between fatigue crack growth rate and stress intensity factor obtained from finite element analysis and existing proposed formulae.
Relationship between Prevalence of Musculoskeletal Symptoms and Occupational and Personal Factors among Street Cleaners
Jung, Suk-Chul ; Lee, Kyung-Sun ; Jung, Myung-Chul ; Lee, In-Seok ; JungChoi, Kyung-Hee ; Bahk, Jin-Wook ; Kim, Hyun-Joo ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 169~179
The aim of this study was to investigate occupational and individual risk factors and working conditions in relation to musculoskeletal symptoms in street cleaners. Investigation was conducted through a survey of 395 male street cleaners employed by the government office in Seoul, Gyeonggi and Chung-Nam from July to August of 2009. The control group was comprised of 143 male drivers and security guards. Risk factors for musculoskeletal symptoms in street cleaners were investigated by multiple logistic regression analysis and also evaluated ergonomic risk factors by assessing working conditions of 4 street cleaners. As a result of symptom questionnaires, all of the prevalent rates of musculoskeletal symptoms in street cleaners had significantly higher results than those of the control group(p<0.05). On binary logistic regression analysis of musculoskeletal symptoms, street cleaners showed significant higher odds ratio as 18.84(95%CI: 6.56-54.12) in the arm/elbow, 10.49(95%CI: 4.29-25.65) in the hand/wrist compared to the control group. Both absence of rest breaks and exposure to ergonomic risk factors showed to be important internal risk factors of musculoskeletal symptoms among street cleaners. The exposure levels of QEC(Quick exposures checklist) in street cleaners were revealed to be higher on the shoulder/arm, wrist/hand, and neck than back, or from stress. The findings appear to show that street cleaners were high-risk group of work-related musculoskeletal disorders. Therefore street cleaners require a holistic interventional strategy, including adequate arrangement of rest breaks, improvement of working tools and control of individual risk factors such as obesity and smoking.
An Analysis of the Hazardous Highway Segments Using Continuous Risk Profile Method
Lee, Soo-Il ; Yu, Jun-Seok ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 180~185
We have to develop more correct and systematic way to choose Hazardous Highway Segments. In this research, we applied CRP(Continuous Risk Profile) technique which developed by UC Berkeley Traffic Safety Center in year of 2007, and can analyze yearly dangerous level tendency of continuity in the route of main road that is under California Department of Transportation(Caltrans). We changed standard of CRP to suit in Korean circumstance with consideration in radius of curve and traffic volume. For the verification by actual accident data, we embodiment the CRP by using the data from total of 587 case of accident in latest 10 years in Gyeong-Bu Highways, the amount of 56km. Finally, the effectiveness of technique in this research has been verified by obtained same result with current method for Hazardous Highway Segments. In addition, when calculating the Hazardous Highway Segments with technique that presented in this research we obtained following statements. First, identified dangerous level of continuity in the route by using CRP. Second, Accurate of Actual Hazardous Highway Segments selection has been developed by using last 10 year's data and profile making which provide simplicity analyze of Tendency. Third, after reforming the way of selection, effective range has been wider than former selection and it gives advantage for the policy side.
Evaluation of Highway Design Alternatives Based on Reliability Criterion for Traffic Safety
Oh, Heung-Un ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 186~196
It has been well known that traffic accidents occur under combined functional contributions of drivers, vehicles and road facilities, and that evaluation of safety levels for a specific road section or point is generally much complicated. Additionally, most of traffic accidents occur randomly implicating it is necessary to be evaluated in terms of probability theory. Thus, the evaluation model which reflects various characteristics and probabilistic distributions of traffic accidents has been necessary. The present paper provides a reliability based model with variables of probabilistic operating speeds and design speeds together which have been individually explaining associated characteristics in traffic accidents. Consequently, the model made it possible for speed management and road improvement projects to be evaluated in a common index. Application studies were performed in three cases. Through the studies, couples of facts were identified that the model successfully considered the probabilistic operating speeds and design speeds together and that then, the model evaluated road safety alternatives relatively which are complicatedly characterized and differently located.
Developing the Traffic Accident Models of Arterial Link Sections by Driving Type
Kim, Kyung-Hwan ; Park, Byung-Ho ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 197~202
This study deals with the accident models of arterial link sections by driving type. The objectives is to develop models by driving type using the accident data of 24 arterial links in Cheong-ju. In pursuing the above, this study gives particular emphasis to modeling such the accidents as the straight, lane change and others. The main results analyzed are as follows. First, the number of accidents is analyzed to account for about 59% in straight, 31% in lane change and 10% in others. Second, the number of left-turn lane as common variables, and the ADT, number of pedestrian crossings, connecting roads and link length as specific variables are selected in developing models(number of accident and EPDO). Third, 8 models which are all statistically significant are developed. Finally, RMSE of the driving type models was analyzed to be better than that of dummy variable.
Development of Protocol Analyzer Suited for Maintenance of LonWorks Netwo가 for Safety Management of Underground Facilities
Kim, Hyung-Ki ; Choi, Gi-Sang ; Choi, Gi-Heung ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 203~209
A compact ANSI/EIA 709.1 protocol analyzer system suited for maintenance of LonWorks network for safety management of underground facilities was developed and tested. The hardware is based on the TMS320LF2406A embedded system, and the software was designed using Visual C++6.0 under Windows XP environment. Connected to the LonWorks network the developed protocol analyzer decodes the raw packets and pass them to the master PC through USB port. Then on the PC the packets are processed and analyzed in various aspects and the key features that are essential to the maintenance of LonWorks network installed at underground facilities are displayed in a user-friendly format. Performance of the developed protocol analyzer was evaluated through a series of experiments, by measuring the speed of packet analysis and the error rate. The protocol analyzer proved to work reliably even under the increased bandwidth. However, more comprehensive tests under various underground environmental conditions are desired.
Analysis of Carbon Emissions from Combustion of Three Arbor in Youngdong Area
Park, Young-Ju ; Lee, Hae-Pyeong ;
Journal of the Korean Society of Safety , volume 25, issue 6, 2010, Pages 210~215
In this study, when the forest fire occurred, in order to estimate greenhouse gas emissions, tree glow in Gangwon Youndong area, Juglans mandshurica, Alnus japonica, Acer palmatum of carbon dioxide and carbon monoxide emissions were about. Water content were measured before the experiment, Juglans mandshurica 196.24%, Alnus japonica 169.17% Acer palmatum 210.10% moisture content showed a big difference, Living leaves of Acer palmatum were a lot of moisture. Also, 50g weight of carbon dioxide on the Juglans mandshurica 53.3644g, Alnus japonica 49.4256g, was released about Acer palmatum 51.3394g, Juglans mandshurica living leaves were the most carbon dioxide emissions. Carbon monoxide emissions result, About weight 50g Juglans mandshurica 1.5329g, Alnus japonica 1.7189g, 2.5002g about Acer palmatum was released, Acer palmatum living leaves were the most carbon monoxide emissions.