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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Safety
Journal Basic Information
Journal DOI :
The Korean Society Safety
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Volume & Issues
Volume 11, Issue 4 - Dec 1996
Volume 11, Issue 3 - Sep 1996
Volume 11, Issue 2 - Jun 1996
Volume 11, Issue 1 - Mar 1996
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Dynamic Stress Intensity Factors and Dynamic Crack Propagation Velocities in Polycarbonate WL-RDCB Specimen
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 3~9
Dynamic fracture characteristics of Polycarbonate WL-RDCB specimen were investigated. The dynamic crack propagation velocities in these specimens were measured by using both high speed camera system and silver paint grid method developed and justified in the INHA Fracture Mechanics Laboratory. The measured crack propagation velocities were fed into the INSAMCR code(a dynamic finite element code which has been developed in the INBA Fracture Mechanics Laboratory) to extract the dynamic stress intensity factors. It has been confirmed that both dynamic crack arrest toughness and the static crack arrest toughness depend on both the geometry and the dynamic crack propagation velocity of specimens. The maximum dynamic crack propagation velocity of Polycarbonate WL-RDCB specimen was found to be dependent on the material property, geometry and the type of loading. The dynamic cracks in these Polycarbonate WL-RDCB specimens seemed to propagate in a successive manner, involving distinguished 'propagation-arrest-propagation-arrest' steps on the microsecond time scale. It was also found that the relat-ionship between dynamic stress intensity factor and dynamic crack propagation velocities might be represented by the typical '
Development of the New Type Nozzle and the Thermal Deformation at Workpiece in Grinding
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 10~19
Grinding temperature and thermal deformation(dimensional error) are studied theoretically and experimentally. The propose of this research is clarified loading phenomena and residual stress In order to guide nozzle's efficiency. The main results to be obtained are as follows ; 1) When grinding condition Is high efficient grinding, FEM program is developed about grinding heat and dimensional error. 2) Thermal deformation depend on temperature distribution is in good agreement with experimental results in case of little grinding energy flux but is comparatively in good agreement with in case of large (3.5
J/m). 3) In terms of high efficient grinding at field(table speed 4m/min), grinding fluid (dilution 5/100) obtained a good workpiece quality and decreased a grinding temperature. 4) A surface roughness, dimensional error, residual stress and loading phenomena with guide nozzle are decreased and these results obtained a good workpiece quality.
A study on the Fracture Mechanical Strength Evaluation in Joint Interface of Ceramics and Metal
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 20~24
Indentation fracture method and 4-point bending test are carried out to measure the residual stresses and the bending strength, and to investigate the mechanism of fracture mechanics in the bonded interface of ceramic and metal. The results obtained are as follows ; 1) The fracture patterns of bonded materials shows that the delamlnatlon fracture of Interfaces is stablely developed from the interfaces of ceramic/active metallic bonded materials at the specimen center, and the fracture is unstablely generated through a refraction on the middle ceramic. 2) Distribution of residual stresses is quantitatively investigated on the ceramic side of bonded materials. 3) It Is found that the residual stresses of interface vertical direction are concentrated on the bonded interface at the ceramic side.
Measurement of harmful factors occurring in Machinery and Core workshop
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 25~32
This study is a survey on the effect of working security and worksite environment connected to the worst case of noise and dust which was generated in the manufacturing workshop of machinery and easting. The noise intensity of the manufacturing process tends to increase up to the limited strength of 90db (A) or the higher during the last 4~5 years in 1990~1994. This result requires a significant improvement of worksite environment of unit workshop. The concentration of dust in the gouging process tends to increase to a significantly high level compared with other worksite, which also requires a local ventilation method to reduce the dust diffusion. Organic solvents used most frequently in the manufacturing process machinery were the aromatic hydrocarbons, but were gradually diversed in recent years.
The energy absorption characteristics of thin-walled members for the use of light-weight vehicles
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 33~43
In this paper, collapse test of thin-walled structures, which are widely used in the vehicle members is carried out to observe the dependence of cross-sectional forms and materials on the absorbed energy in the viewpoint of crashworthiness. Also, specimens consist of two kinds (Al, CFRP) with various thickness. Comparisons of circular specimens are made to find characteristics of the different specimens on the absorption ability according to specimen thickness and materials.
A study on the Impact damages and residual strength of CFRP laminates to impact under high temperature
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 44~52
An experimental study on the effects of temperature change on the impact damages of CFRP aminates was made through an observation of the interrelations between the Impact energy vs. delamination area, the impact energy vs. residual bending strength, and the delamination area vs. the decreasing of the residual bending strength for CF/EPOXY and CF/PEEK composite laminates subjected to FOD (Foreign Object Damage) under high temperatures.
A Study on Improvement and Estimation of Fatigue Strength in Sintering Spur Gear
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 53~58
This paper deals with the bending fatigue strength of sintering spur gears. The test specimens are used to sintering spur gear to be consisted of Fe-C-Ni-Mn and SCM415 spur gear. The fatigue test at a constant stress amplitude is performed by using an electrohydraulic servo-controlled pulsating tester. The S-N curves are obtained and the enhancement of fatigue strength due to carburized treatment is clarified, Accordingly, this study presents the fatigue strength of sintering spur gear, SCM415 spur gear and carburized gears of them. The strength enhancement due to the carburized treatment is discussed.
The Study of Dynamic Fracture Characteristics for Tempering Temperature of STD-11
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 59~65
This study is to evaluate dynamic fracture characteristics of alloy tool steel, STD-11, according to various tempering conditions (heat treatment). The dynamic fracture initiation toughness and some of the dynamic fracturing characteristics were evaluated by using the instrumented Charpy impact testing procedures. The distributions of Victors hardness and dynamic fracture initiation toughness with respect to varying tempering temperatures are found to be symmetric type with the help of experimental results for the STD-11. It is also found that the dynamic fracture initiation toughness is a inverse proportion to Vickers hardness. In this experimental study, it is found that the best heat treatment condition is 55
tempering in alloy tool steel, STD-11, because the results show high values of Vickers hardness and dynamic fracture initiation toughness.
Validation of the Reynolds Stress Turbulence Models in Turbulent Jet Diffusion Flames
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 66~74
Numerical simulations were carried out using standard Reynolds stress turbulence model(LRR model) and modified RSM(Janicka model ) to validate these models in combustion flow fields. Two flames were selected for use as a benchmark data for model testing. One is a conventional jet diffusion flame that has the effect of suppression of turbulence by combustion. The other is a triple jet diffusion flame that designed to give high turbulence to the periphery of the flame and to remove the low Reynolds-number flow fields. As a result, it was found that the modification of standard RSM model is indispensable in the modelling of flames with low turbulence region. And it is also necessary to improve the existing modified models for the universal use.
A Study on Characteristics and Safety for Human Body in ELF Electric and Magnetic Fields using Statistical Method
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 75~80
This paper presents a study on characteristics and safety for human body in ELF electric and magnetic fields using statistical method. The magnetic fields from a power line can be computed given a knowledge of the currents, voltage and geometry of the line. In this paper, a statistical method for predicting the magnetic fields given the inherent indetermination of the currents is presented. But the electric field is calculated given a knowledge of the voltage and geometry of the line. The effect of unexpected fluctuations in current is modeled by the Monte Carlo simulation. The suggested method is applied to the 345kV and 765kV transmission line system, the result shows that the maximum electric and magnetic field intensity is 6.8627kV/m and 284mG in 345kV system, 2. 5590kV/m and 35mG in 765kV system, respectively.
A Study on the Electrical Properties of Transformer Oils for Large Power
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 81~88
In order to investigate the electrical properties of transformer oils for large power, the characteristics of AC and Impulse breakdown in gap length of 1.0~2.5mm and that of volume resistivity were researched in temperature range of 20~
. An geometrical capacitance of electrode with coaxial cylindrical shape for measuring the volume resistivity was 16pF, and highmegohm meter with model no. VMG-1000 was used, and also the applied voltage were DC 100, 250 and 500V. In the dependance of breakdown characteristics due to electrode gap length, it was confirmed that breakdown voltage was nearly uniform by volume effect according to the increase of gap. In the characteristics for AC breakdown, the dielectric strength was increased to
but decreased over
, and also in case of impulse breakdown, it was increased to 7
and at dated
over in temperature range. The calculated mobility of oils in the characteristics for impulse breakdown were about
, and the value of volume resistivity was almost invariable in low temperature range, regardless of voltage by the stable thermal properties, and it indicated a peak at
and had a sudden change to decrease over that temperature, and also the value of volume resistivity in 250V/mm at
is suitable for the International electrical standards, it was confirmed.
ELF Electric and Magnetic Fields under the Transmission Line Including Electric Power System States
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 89~96
This paper presents a study on the analysis and evaluation for ELF( Extremely Low Frequency) electric and magnetic fields under the transmission line according to the power system states. The power system states are classified into two types, normal state resulting from normal operation and alert state from outages. The current in a system is changed continually owing to the load fluctuations even in a normal operation. To calculate the current of the concerned line in a normal state, the system load level is devided into light, base and heavy load level. In case of contingency, an efficient algorithm based on matrix inversion lemma is developed to figure out the current changes. In order to analyze the variations of ELF field caused by the current fluctuations the electrostatic field approach which is far simpler than the electromagnetic field one based on Maxwell equation is introduced in this paper. The suggested method is applied to the IEEE 14 bus system to demonstrate the usefulness.
Effect of Temperature and Pressure on the Weldability of Polyethylene Pipe for the Supply of Gaseous Fuels
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 97~103
The welding characteristics of polyethylene pipe for gas varying temperature and pressure is analyzed in this study. The analysis is very important to studying the weldability of PE pipe as well as is useful for its welding data. The specimens have the same welding conditions. Experimental data of the bead width, height and thickness for PE welding are measured with tool projector, Experimental results for PE welding Indicated that temperature more than pressure have influence on the weldability. It was confirmed that optimal PE welding within the limits of
have high welding performance in comparison with other conditions. These results are very important to improve the safety and to reliable welding components of PE gas pipe.
A Study on Knowledge Representation for Recognizing Hazardous States in Chemical Processes
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 104~111
A system was developed that could predict hazardous states for safe operation of chemical plants. This system aimed to prevent hazards of chemical processes from misoperation before real operation. In this study, a data base was organized which consisted of all hazards in the chemical processes. The structure of process was represented by signed direct graph(SDG) of NODEs and ARCs. Each NODE and ARC have property variables ; connected structure and state of processes etc. The hazards that could be occurred in processes were divided into two classes ; one is by operation of unit and the other is by hazardous materials. Using Hazardous States Transition Network, we could recognize transition progress of process states.
Removal of carbon monoxide using a solid electrolyte cell reactor
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 112~118
When fossil fuels are burned they produce CO gas because of incomplete combustion. If the CO gas reacts with the hemoglobin in the red blood cells, it may result in death or sequelae. Generally, the CO gas is eliminated in the form of the
gas by the oxidation reaction over the platinum catalyst. In this study, the electrochemical CO removal was investgated by using the solid electrolyte cell reactor, the type of which was represented as reactants
. If the overpotential was applied to the platinum working electrode, the conversion could be changed with the overpotential applied. It was found that the oxidation rate could be increased 2.8 times higher than that of the normal condition, i. e. under open circuit conditions when
was 0.5 and overpotential was 0.9V. From these results, it is concluded that the reactor used in this study is more efficient than conventional catalytic reactors.
Experimental Study on the Flue Gas Phenomena in Infrared Mobile Heaters
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 119~125
The experimental work is performed to obtain content levels and characteristics of flue gas in infrared mobile heaters for butane gas with varying the chamber size and its room temperature. The results showed that the oxygen depletion sensor device is operated at 18.3% of oxygen content. And the relation of oxygen content and carbon dioxide content in an enclosed space show linear aspect, but the content rate of carbon monoxide occurs at random without the level of oxygen content and carbon dioxide content.
Properties and Controls of hazardous gases from Electrochemical fluorination of Methanesulfonyl chloride
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 126~136
Synthesis of perfluoromethanesulfonyl fluoride(PFMSF) which is a valuable precursor of perfluoro-chemicals such as surface modifier and fine chemicals was studied by electrochemical fluorination (ECF). In order to determine the termination of preelectrolysis, it was carried to monitor the variation of current during preelectrolysis by means of constant cell voltage operation. In a batch cell, chronopotentiometric electrolysis and various chemical analysis such as GC, GC/MS and If were used to understand the potential change of electrode and synthesis and control of hazardous gases products. Termination of preelectrolysis was determinated by measurement the current and/or detection of
gas generation. And during the preelectrolysis, an amount of generated
was shown that a lot of moisture was absorbed from air when a cell was filled with anhydrous hydrogen fluoride( AHF ). Above 4V cell voltage,
gas was generated and acted on any form of fluorinating agents. In the ECF of MSC (methane sulfonyl chloride) by constant current operation, the potential of anode was intimately relation with generation of
. Exchange of Cl to F was dominatly occured in a initial stage. There were various gaseous products including PFMSF as main product and
Combustion Characteristics of Immobilized Alcohols in Sands
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 137~142
Combustion characteristics of immobilized methyl, ethyl and propyl alcohols on sands were studied. Experiments were performed by burning methyl, ethyl and propyl alcohols Immobilized on sands (particle size 0.1~5mm) and ceramic balls(particle size 5mm) to measure mass burning rate, height burning rate and combustion temperature. It was concluded that the longer time from ignition to extinguishment was resulted from the larger particle size of sands and the smaller size of sands exhibited the higher mass burning rate. Of alcohols tested the relative magnitude of facilitation of combustion was methyl>ethyl>propyl alcohol. Combustion temperature of alcohols, without regard to the types of alcohols, was not increased with smaller sands. However, with larger sands, combustion temperatare of alcohols was increased with the larger particle.
Knowledge Representation for the Automatic Shutdown System in Boiler Plants
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 143~153
Shutdown of boiler plants is a dynamic, complicated, and hazardous operation. Operational error is a major contributor to danserous situations during boiler plant shutdowns. It is important to develop an automatic system which synthesizes operating procedures to safely go from normal operation to complete shutdown. Knowledge representation for automatic shutdown of boiler plants makes use of the hierarchical, rule-based framework for heuristic knowledge, the semantic network, frame for process topology, and AI techniques such as rule matching, forward chaining, backward chaining, and searching. This knowledge representation and modeling account for the operational states, primitive operation devices, effects of their application, and planning methodology. Also, this is designed to automatically formulate subgoals, search for positive operation devices, formulate constraints, and synthesize shutdown procedures in boiler plants.
An Experimental Study on the Safety of Glass Fiber Reinforced Plastic Pipes under Fatigue Load
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 154~159
In this thesis, a series of loading tests are conducted in order to investigate the fracture safety of GFRP(Glass Fiber Reinforced Plastics) pipes under fatigue load which are widely used in the developed countries becauses of their natural of anticorrosion and lightweight etc. . Fatigue test is performed by changing number of laminates and loading cycles to examine the flexural strains, the ductility and the fatigue strength for two million repeated loading cycles. From the fatigue test results, it was found that the larger the laminates of GFRP pipes is, the larger the stiffness of GFRP pipes under the fatigue load increases. This phenomenon is true until the fatigue failure. According to the S-N curve drawn by the regression analysis on the fatigue test results, the fatigue strength of percent of the static ultimate strength increases by increasing the laminates of GFRP pipes. The fatigue strength with two million repeated leading cycles in GFRP pipes with the laminates of GFRP pipes varing 15, 25, 35 shows about 75%, 80%, 84% on the static ultimate strength, respectively.
A Study on the Stability of the Waste Concrete as the Subgrade Materials
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 160~167
The construction waste concrete produce from the demolished concrete structures. These waste concrete materials are useful and valuable for fill and subgrade and are considered to use as the subgrade material of the road. To use the subgrade of the road with the waste concrete, the several experiments involved with compaction test and laboratory C. B. R. etc. are performed. These experiments are compared with criteria of the road construction manual. It is shown that the quality of the construction waste concrete satisfies that of the subgrade mentioned in the road construction manual.
Historical Review on the Occupational Accidents Proneness
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 168~176
Statistical analysis of occupational accidents plays an important role in establishing measures against accidents and for evaluating safety performance in work places. This research work, numerous numbers of research work have been conducted, which attemped to verify the existence of !he concept of "accident proneness" Also researches have been developed in the fields of systems safety analysis and risk analysis to analyze the characteristics of occupational accidents. This paper presents a brief historical review of these research activities with particular emphasis on the statistical analysis of occupational accidents. Based on this review, further development needs in relation to the statistical research on the occupational accidents in the near future are discussed.discussed.
Analysis of Chronological Changes in the Physical Growth of Korean
Journal of the Korean Society of Safety , volume 11, issue 3, 1996, Pages 177~187
This paper is concerned with the comparison and chronological changes of the physical constitution of the Korean youth, age range 6-17. For the purpose, anthropometric data of schoolchildrens are surveyed from the Statistlcal Yearbook of Education published in Ministry of Education. The results show that body dimensions have increased consistently from 1964 to 1994. During the last 30years, stature has increased by about 1cm to 6cm per decade, on the average, and body weight has increased by about 1kg to 5kg per decade. On the other hand, silting height and chest circumference have increased by about 0.5cm to 3cm per decade. The results also show that there are significant sex differences in the characteristics of physical growth. These findings identified in this study mean that boys and girls have essentially different requirements for the design of the workplace.