Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society of Safety
Journal Basic Information
Journal DOI :
The Korean Society Safety
Editor in Chief :
Volume & Issues
Volume 13, Issue 4 - Dec 1998
Volume 13, Issue 3 - Sep 1998
Volume 13, Issue 2 - Jun 1998
Volume 13, Issue 1 - Mar 1998
Selecting the target year
Computation of Unsteady Separated Flow Using the Vortex Particle Method (I) - Boundary Element Method and Vortex Strength Around the Square Cylinder -
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 3~8
The vortex particle method, which includes viscous effects, consists of diffusion of boundary vorticity and creation of the vortex particles, convection, particle strength exchange, and particle redistribution. Accuracy of the boundary element method is very important since it creates the particles around the body at every time step. A boundary element method based on source panel was investigated as part of computation of unsteady separated flows by rising the vortex particle method. The potential flows were computed around a circular cylinder and a square cylinder. The results around the circular cylinder were compared with the exact solution, and the distribution of vorticity, in particular near the sharp comers of the square cylinder, is scrutinized for different number of panels.
A Study for Energy Separation of Vortex Tube using Air Supply System (I) - the effect of diameter of cold end orifice -
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 9~18
The vortex tube is a simple device for separating a compressed gaseous fluid stream into two flows of high and low temperature without any chemical reactions. Recently, vortex tube is widely used to local cooler of industrial equipments and air supply system. The phenomena of energy separation through the vortex tube was investigated experimentally. This study is focused on the effect of the diameter of cold end orifice diameter on the energy separation. The experiment was carried out with various cold end orifice diameter ratio from 0.22 to 0.78 for different input pressure and cold air flow ratio. The experimental results were indicated that there are an optimum diameter of cold end orifice for the best cooling performance. The maximum cold air temperature difference was appeared when the diameter ratio of the cold end orifice was 0.5. The maximum cooling capacity was obtained when the diameter ratio of the cold end orifice was 0.6 and cold air flow ratio was 0.7.
Effects of Specimen Size in Evaluation of Elastic-Plastic Fracture Toughness by Ultrasonic Method
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 19~24
Elastic-plastic fracture toughness(
) by ultrasonic method is evaluated in terms of width and thickness. Widths of specimen in 6061-T6 aluminum alloy are 50mm and 100mm, thicknesses of those are 20mm and 25mm, respectively. Elastic-plastic fracture toughness by ultrasonic method is independent of specimen thickness and side groove. Angle beam probe which are placed on the end of the compact specimen detect the maximum crack extension effectively. Comparing with elastic-plastic fracture toughness by ultrasonic method and that of unloading compliance method,
of ultrasonic method are underestimated to that of unloading compliance method. Elastic-plastic fracture toughness of width 100mm specimen are underestimated to that of width 50mm specimen about 20%.
A Study on the Relations Between Fracture Strain and Elastic-Plastic Fracture Toughness
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 25~33
In this study, under large scale yielding conditions crack propagation is found to governed by parameters based on the J-integral or on the crack opening displacement. But initiation of crack propagation of ductile material seems to be controlled by just on parameter that is the strain. The relationship between the critical value of J-integral and the local fracture strain in uniaxial tensile test in the region of maximum reduction in area. Therefore, the fundamental theoretical equation by the proposed elastic-plastic fracture toughness and the local fracture strain has a merit, in comparison with the ASTM method, which can measure by using the load-displacement curve and the specimens in tensile test.
A Study on the Improvement and the Reliable Design in Sintered Spur Gear
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 34~40
It is very important to have exact informations on the properties and characteristics of the sintered steel as a new material of machine elements. The bending fatigue tests are performed for sintered steel bend specimens and spur gears, which are notched by using a slicing blade. The fatigue test at a constant stress amplitude is performed by using an electrohydraulic servo-controlled pulsating tester. Consequently, the S-N curves are obtained and the fatigue strength is compared with flaw depth. Accordingly, this study presents the fatigue strength of sintered spur gears, the critical notch depth of sintered steel and the effects of flaw depth on the bending fatigue strength. The enhancement of fatigue strength due to carburized treatment is clarified.
A study on the fracture toughness of dynamic interlaminar for CFRP composite laminates
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 41~48
In this paper, an investigation was performed on the dynamic interlaminar fracture toughness of CFRP(carbon fiber reinforcement plastics) composite laminates. Composite laminates used in this experimentation are CF/EPOXY and CF/PEEK laminated plates. In the experiments, Split Hopkinson's Bar(SHPE) test was applied to dynamic and notched flexure test. The mode Ⅱ fracture toughness of each unidirectional CFRP was estimated by the analyzed deflection of the specimen and J-integral with the measured impulsive load and reactions at the supported points. As an experimental result, the vibration amplitude of CF/PEEK laminates appear more than that of CF/EPOXY laminates for the J-integral and displacement velocity at a measuring point. Also, it is thought that the dynamic fracture toughness of two kind specimens(CFRP/EPOXY and CF/PEEK) with the in crease of displacement velocity becomes a little greater at a measuring point within the range of measurement.
Influence of Spring Constant and Tip Mass at Free End on Stability of Timoshenko Cantilever Column subjected to a Follower Force
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 49~58
On the stability of the Timoshenko cantilever column subjected of a compressive follower force, the influences of the moment of inertia of the tip mass at the free end and the characteristics of a translational spring at the free end of the column are studied. The equations of motion and boundary conditions of system are estabilished by using the d'Alembert virtual work of principle. On the evaluation of stability of the column, the effect of the shear deformation and rotatory inertia is considered in calculation. The moment of inertia of the tip mass at the free end of the column is changed by adjusting the distance c, from the free end of the column to the tip mass center. The free end of the column is supported elastically by a translational spring. For the maintenance of the good stability of the column, it is also proved that the constant of the translational spring at the free end must be very large for the case without a tip mass while it must be small for the case with a tip mass. Therefore, it is found that the shape of the tip mass and the characteristic of the spring at the free end are very effective elements for the stability of the column when the columns subjected to a compressive follower force are designed.
Response Time Index and Suppression Capability of Standard and Quick Response Sprinkler Head
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 59~70
In this study, response time index(RTI) of standard and quick response type sprinkler head are measured and compared through ramp and plunge test in heated wind tunnel. Also discharge rate and water distribution, actual delivered density(ADD), fire test with wood cribs are performed to compare the fire suppression capability and the operation time and temperature between standard and quick response type sprinkler head.
Fractal Characteristic Analysis Applied to Fracture Parameter
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 71~78
Real crack and fracture surfaces have irregularities producing zigzag contours. These irregularities are analysed by a fractal geometry which has been by a Mandelbrot. We obtained a fractal dimension which is one of the fractal characteristics. It is also estimated by an vertical section method that fractal characteristics in the fractured surfaces can be obtained as the crack grows. Moreover fractal fracture energy that corresponds to an energy release rate is shown to find relationships between fractal dimensions and crack behaviors. From these results, we concluded that a fractal characteristics analysis for a crack can be applied to a fracture mechanics.
Effect of Specimen Thickness on Fatigue Crack Growth
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 79~86
The effect of specimen thickness on fatigue crack growth behavior has been carried out by compact tension specimens of thickness of 3mm, 10mm and 25mm for maraging steel and Al 7075-T6. The closure points were determined during the test by means of a clip-gage situated at the notch mouth. Specimen thickness have no apparent influence on the fatigue crack growth rate of maraging steel, but the crack growth rate of 25mm thickness specimen for Al 7075-T6 is faster than that of 3 and 10mm specimens. The difference of crack growth rates can be successfully explained by considering the different stress state of plane strain and plain stress due to the variation of specimen thickness. Also the crack opening ratio of 25mm specimen is greater than those of 3 and 10mm specimens. When a side groove is introduced in a 10mm specimen, the crack growth rate is approximately similar to that of 25mm specimen. The effective thickness expression of
is the most appropriate to evaluate the crack growth rate of side-grooved specimen. Fatigue crack growth rates can be well described by
of the crack closure points in regardless of all thickness and side-grooved specimens.
A Study on the Effect of Welding Conditions on Fume Generation Rate in
Flux Cored Arc Welding
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 87~95
The use of flux cored arc welding(FCAW) process has grown dramatically since it has been developed because of the remarkable operating characteristics and the resulting weld properties. The feature that distinguishes the FCAW process from other arc welding processes is the enclosure of fluxing ingredients within a continuously fed tubular electrode. The benefits of FCAW process are the increased productivity due to continuous wire feeding, the metallurgical effects derived from the reactions with flux, and the shapes of weld bead formed by slag. However, FCAW process causes the problem in working environment because it generates much more fume than other welding processes. Recently, the welding fume became a hot issue in the field after some welders were diagnosed as manganese toxcosis and siderosis. This study was started to investigate the characteristics of welding fume and utilize the results from the investigation to protect the welders from welding fume. As a first step, the effect of welding conditions on the fume generation rate(FGR) were investigated during FCAW process with
shielding. The considered welding conditions were welding current, arc voltage, travel speed, contact tube to work distance, and torch angle. The results showed that FGR was affected by all of these factors.
J-R Curve Evaluation According to the Crack Length Measurement Techniques Under Reverse Cyclic Loading
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 96~101
J-R curve tests were performed on 1T compact specimens of SA516 Gr. 70 carbon steels under reverse cyclic loading. A Direct-Current Potential Drop (DCPD) method, one of the nondestructive techniques to detect flaw of structure, is being increasingly used for monitoring crack initiation and stable crack growth in typical fracture mechanics specimens for J-R testing. In many aspects this method is simpler than the unloading compliance method. The objective of this paper is to evaluate the J-R Curve according to the crack length measurement techniques under reverse cyclic loading. In order to prove the reliability and repeatability of the DCPD method, the crack length measured by using DCPD method was compared to one determined from unloading compliance. Consequently, this DCPD method correlated well with J-R curves and crack extension measurements determined from unloading compliance method.
A Study on the Noise Generation Cause and Vibration Damping Characteristics of Shock Absorber
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 102~112
Shock absorber has a great influence on the performance of the vehicle(ride comfort, manipulation, noise, vibration, turning, stability). Therefore, in this study we consider theoretically about general damper, variable damping oil damper, the control of vehicle Characteristics for the suspension, and undesirable phenomenon. And we measured the vibration/noise characteristics of shock absorber for the real car experimentation, strain change, and noise characteristics of shock absorber using experimental equipment. The study of domestic company and research institute on the vehicle shock absorber is active, but that of basis is not. So we think that they should be accomplished actively. Therefore, this paper will develop theoretical system on the vibration/noise characteristics of shock absorber by theoretical consideration and experimental result analysis of dynamic characteristics of shock absorber that were accomplished in this study. Then we will use it as the optimistic design data for shock absorber development.
A Study on Corrosion Fatigue Crack Growth Behavior in Al-Alloy 7075-T651 (I)
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 113~120
Fatigue crack growth rates(i.e. crack initiation and crack growth of short and long crack) are investigated using commercial plates of high strength Al alloy 7075-T651 for the transverse-longitudinal(T-L) direction in air, water and sea water. Also, the evaluation direct current potential drop(D.C.P.D) method and the fractographical analysis by SEM are carried out. Near threshold region, short crack growth rates were much faster than those of comparable long cracks, and these short crack growth rates actually decrease with increasing crack growth and eventually merge with long crack data. Fatigue crack propagation rates in aggressive media(i.e. sea water) increase noticeably over three times those in air. One of the most significant characters in this phenomenon as a corrosion-fatigue causes an acceleration in crack growth rates. Sea water environment, particularly Cl
solution brings the most detrimental effects to aluminum alloy. The result of fractographical morphology in air, water and sea water by SEM shows obvious dimpled rupture and typical striation in air, but transgranular fracture surface in water and sea water.
Effects of the Glass Fiber Synthetic Rate on the Characteristics of Fatigue Failure for Nylon 6
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 121~130
In recent years, a number of metal machine parts, in the field of the car manufactures and electronic goods for home, have been replaced by nylon-6 in order to weight, cost, and a period of process of manufacture. It's because nylon-6 materials as an industrial material have higher economical and productive advantage than the metalic ones. However, in domestic injection manufactures, there are few data on fiber glass synthetic on nylon-6. It is said that plastic in process of manufacture using the same injection materials make their results different in large scale according to fiber glass synthetic rate conditions. In this study, we have studied effects of the glass fiber synthetic rate on the characteristics of fatigue failure for nylon-6.
A Study on the Creep Behavior and Failure Mechanism of the
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 131~136
The creep behavior and failure mechanism of the 30 vol% hot-pressed
ceramic composite was experimentally investigated at
and at various stress levels in air. The creep threshold stress for zero creep rate after 100 hr was found to be approximately 60 MPa. The stress exponent was estimated to be n~1, which suggests that fiber-reinforcement reduced the stress sensitivity of the HPSN matrix with the stress exponent of 2. The tertiary stage leading to creep rupture was found at 250 MPa but was very short. The microstructure of the crept specimen showed random fiber fracture and no matrix cracking. Interfacial debonding was absent.
A Study on the Combustion Response Function of the Solid-Propellant
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 137~141
The combustion instability of a rocket motor can be predicted by the linear stability analysis. The most important input data in this analysis is the combustion response function of the solid propellant. In many cases, it is very difficult to measure the function. But, in that case, the combustion response function can be theoretically evaluated by properties of the propellant. In this study, the theoretical values were compared with measured values by T-burner. Data are relatively so well agreed that theoretical values are enough to be used in linear stability analysis of the rocket motor using a newly developed propellant.
A Study on the Theoretical Analysis and Optimal Design Conditions for the
type Stirling Engine
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 142~154
A stirling engine is a mechanism used to convert heat to power and operates on a closed regenerative thermodynamic cycle with compression and expansion of the working fluid at different temperature. The performance of a stilting cycle machine is a function of six independent parameters, namely; (1) speed N(r.p.m), (2) pressure of the working fluid p(Pa), (3) ratio of the temperature in the compression and expansion space
, (4) ratio of the swept volumes in these two spaces K, (5) phase angle
and (6) dead volume ratio X. This paper describes the procedure and presents the results of computations carried out to establish the optimum combinations of these six parameters for maximum engine output for the machine acting as a prime mover, over a combined temperature range from
and dead volume ratio X ranging from 0.1 to 2.0. The output of a stilting cycle machine can be expressed in terms of nondimensional power in several different ways. Four methods were studied in detail, the parameters optimized and design charts and engine power charts prepared. The results of this paper may be useful as a guide to the likely effects on the performance of some of the important design parameters and regenerator design.
Influence of the Distribution of Wind Velocity and Mist Concentration for the Improvement of Efficiency with an Electrostatic Precipitator
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 155~161
Recently, there are widely needs of small scale electrostatic precipitator(ESP) in machine shop and other factories. Since the space of such factories is limited, the improvement of collection efficiency is predominant subject. In this study, we examine the influence of distribution of wind velocity and oil mist concentration inside the ESP in order to improve the performance of the ESP. The distribution of wind velocity and mist concentration is measured respectively in a cross-sectional plane of the ESP. The former is controlled by using a louver which is placed in front of an ionizer and the latter is controlled by lengthening the pipe of entrance of the ESP in order to have plenty of time that mist is dispersed evenly. It is shown that the uniformity of distribution of wind velocity and mist concentration inside the ESP can be getting by adopting a louver with proper shape and lengthening the pipe of entrance and is also contributed to collection efficiency considerably.
A Study on the Real Features of Harmonic Obstacle
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 162~171
This paper presents the harmonics obstacle analysis and countermeasure of electrical consumption a place. Harmonics that can be cosidered as a environmental pollution of the power systems become the cause of the accidents and damages. The responsibility of eliminating the harmonics firstly lies on the generating side. But the original characteristics of the system sush as the harmonic transfer characteristics and the impedance of the system affect each other in the process of the generation and transmission of the harmonic. Therefore it is very difficult to specify clearly the harmonic controlling responsibility, because electric machinery generating harmonics are various in the industrial fields. The output of a inverter has a high harmonic content. There are several ways of minimizing the output harmonic content. One way is to use pulse width modulation techniques within inverter. An alternative method is to combine a number of square-wave inverters. In this research, we measure the harmonic of the countermeasure of electrical consumption a place. The paper present the problem of new harmonic elimination method of PWM inverter fed induction motor system using W-FT series. In the future, the proposed PWM pattern by W-FT series is effective not only to the induction motor but also to the electromagnetic machine such as voltage reglator, UPS.
Irradiation on TSC Characteristics of Polytetrafluoroethylene
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 172~179
The effects of
irradiation on TSC characteristics of TFE type polytetrafluoroethylene(PTFE) were investigated. The
peak on TSC curve of PTFE was decreased, while the
peak was reversely increased by the increasing of
-irradiation doses up to 80 krad(0.8 kGy). Moreover,
peaks on TSC curve of the irradiated PTFE are changed with the increasing of the forming temperature and forming electric field. In annealing the irradiated PTFE specimens at room temperature in air, it was shown a continuous recovery of TSC characteristics with time, which is assumed the traped charge carriers are liberated from the shallow traps and undergoes a recombination process during room temperature decay.
A Study on the Thermal Decomposition Characteristics of Intermediate of Saccharin
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 180~185
The evaluation of thermal and pressure hazard of chemicals on the manufacturing, transporting and storaging is important in the chemical industry for safety. In this study, the thermal decomposition characteristics of intermediate of Saccharin were investigated by using Accelerating Rate Calorimeter(ARC) and Differential Scanning Calorimeter(DSC). Experimental results showed that decomposition temperatures in p-TSA were about 280~
by DSC and
by ARC. In case of o-TSA were about
by DSC and
by ARC. The decomposition temperature acquired by ARC was about
lower than that by DSC. The exothermic runaway reaction in case of p-TSA occured in 598 minute and o-TSA in 5 minute. For the safety in the chemical industry, we should consider the ARC data as well as DSC data in the handling and design of process.
A Study on the Distributions of Heavy Metal Concentration in a Soil near Abandoned Mine
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 186~191
This study was investigated the distributions of heavy metal concentration in a soil near abandoned mine in Chung thong Nam Do. The abandoned mines were Gubong gold mine and Sinsung coal mine. The results were as follows : 1) The concentration of As and Pb in Gubong mine were 309.2mg/kg and 1163.5mg/kg, that is exceeded the countermeasure criteria. Cadmium concentration was 14.70mg/kg, that is exceeded anxiety criteria. But all items in Sinsung coal mine was detected below criteria. 2) The heavy metals contamination of riverbed soil by gold mine showed higher than coal mine. 3) The heavy metals contamination in the vicinal paddy and dry field soil area was higher than other mine. Arsenic concentration was 29.29mg/kg, that is exceeded the anxiety criteria as 10.22mg/kg.
Prediction and Representation of Boiling Points for Combustible Solution of Quaternary Systems
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 192~198
MRSM(modified response surface methodology)-2 model is presented for the prediction of boiling points in combustible solution of quaternary systems. This model requires only normal boiling points of pure substances and group-group parameters which are based on the group-group concepts without the use of experimental data under consideration. By means of this methodology, it is possible to predict the boiling points of the combustible mixture of quaternary systems by plotting of isothermal lines using computer graphics. The proposed methodology has been tested and compared successfully with reported boiling points in journals for the combustible solution of quaternary systems. It is hoped eventually that this methodology will permit prediction of the flash point and flammability limit for the combustible mixture of multicomponent systems.
The Fusion Characteristic Varying with Butt Fusion Times for Polyethylene Pipe
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 199~205
Butt fusions were practiced with butt fusion in the various conditions of fusion temperatures, pressure and time, and the tests of tesile strength, breaking water pressure and fusion features were also practiced so that the reliability of the butt fusion and the fittets fusion condition may be closely examined. And the width, height and thickness of the beads were also closely measured. The fittest fusion result was achieved in the condition of the temperature of
, heating time hight pressure of 14 seconds on the pressure of
, heating time hight pressure of 100 seconds and pressure buid-up time of 11 seconds. And in case of the temperature of
, the fittest fusion result was showed in the condition of the heating time hight pressure of 3 seconds on the pressure of 1.0
, the heating time low pressure variable of 100 seconds. heating time hight pressure of 14 seconds and the heating maintenance of around 60 seconds. The result of breaking water pressure test of a test piece fusion in the fittest fusion condition was that the fusion condition of the PE pipe showed a good stability and hight reliance. Through this test, it is proved that the temperature of fusion PE pipes can be increased to
. And it can be expected that the above fusion method greatly helps to reduce the fusion time.
Effect of Electrolyte Concentration on Water Permeation in Protective Coatings
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 206~212
The water permeation in protective coatings, which may greatly influence the corrosion protective property of these coatings, was studied using the electrochemical impedance spectroscopy technique. During the absorption of water in protective coatings immersed in electrolyte solution, the change of coating capacitance with concentration of electrolyte was determined from impedance measurements. When water absorption or desorption of coatings occured by exposing the coatings to electrolyte solutions of different concentration, increase in impedance caused by desorption of water was found to be higher in the case of thicker film. The amount of water absorbed in coatings changed with concentration of electrolyte. The water taken up in coatings from the solution of lower electrolyte concentration was deserted by contact with the solution of higher concentration. The uptake of water in protective coatings varied depending on the type of coating ingredient especially binder.
A Fracture Behavior of Connections of Structural Steel Members under Low Temperature
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 213~220
Welding structures will be occurred sudden crack or failure by reduced fracture toughness in case of low temperature. To protect these unstable fracture is very important. Because fracture of welding part come from welding faults or residual stress, critical stress intensity factors are acquired at temperatures between
from base metal, welding metal and H.A.Z. It was studied effectiveness of annealing and affection of residual stress under low temperatures. In case of fracture toughness test, it showed that fracture toughness value decreased, according to the decrease of temperature. Expecially In case that compressive residual stress was existed,
A Study on Prevention of Major Accidents Through Utilization of Fall-Preventing Safety Installations
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 221~229
This study, with a view point to prevent accidents arising from steel structure, construction process, has taken an approach of reviewing related materials and construction safety guidelines, conducting questionnaire surveys and on field surveys. This study has also analyzed and classified accident cases and disclosed elements concerned with those accidents. A comparative analysis of the disclosed elements against the statutory provisions regarding industrial safety and it showed that strict observance of safety rules of the accident prevention measures in industrial safety standards will result in a decrease in accidents. It is concluded, however, that additional accident prevention measures, as suggested below, should be implemented for performing of more practical and positive accident prevention. 1) Thorough review and preparation at pre-working stage at sites : Such elements of fall preventing facilely as supporting ropes and steel fabrications for safety guard rails should be initially reflected on detailed drawings and shop drawings so that they can be installed in advance at fabricating plants. 2) Sets of steel frame stairs for work platform should be installed or secured with priority and temporary installation of such prefabricated platform as scaffolds should be installed in advance with those platform attached to the frame members on the ground whenever possible before they are lifted. 3) A decrease in the rate of accident by more than 10% on Tuesdays and Thursdays, has been shown from the accident analysis so schedule of construction process should consider possible weekday of high risk of accidents such as Tuesday and Thursday. 4) An array of systemized safety activities should be adopted, such as legal installation of safety facilities based on advance safety management plan, maintenance of safety for machinery and construction equipment, and strict compliance of safety rules by workers.
A Study on Development of a Cognitive Process Simulator Based on Model Human Processor
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 230~239
Though limited, Model Human Processor (MHP) has been used to explain the complex users' behaviors during human-computer interactions in a simplified manner. MHP consists of perceptual, cognitive and motor systems, each with processors and memories interacting with each other in serial or parallel mode. The important parameters of memory include the storage capacity, the decay time, and the code type of a memorized item. The important parameter of a processor is the cycle time. Using these features of the model, this study developed a computerized cognitive process simulator to predict the cognitive process time of a class match task process. An experimental validity test result showed that the mean prediction time for cognitive process of the class match task simulated 50 times by the simulator was consistent with the mean cognitive process time of the same task performed by 37 subjects. Animation of the data flow during the class match task simulation will help understand the invisible human cognitive process.
A Study on the Introduction of Genetic Algorithms for Developments Performance of System
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 240~247
This paper proposed a method for solving the nonlinear integer programing problem to get easily the best compromise solution while holding a nonlinear property by using the genetic algorithms. Also, this paper reported that the optimization problem of systems reliability as was solved by using the preposed method, and the numerical comparison experiments between the 0-1 LP/0-1 NP formulations were demonstrated, and from the quantitative evaluation the efficiency of the proposed method was demonstrated.
A Study on the Evaluations of Compression Force for the Prevention of Low Back Pain : Nine-step Stretching Exercises
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 248~255
The objective of this study is to conduct the prevention method using electromyography that is to resist the strain on L5/S1 disc and to measure the heart rate for the prevention of low back pain during lifting. EMG signals and heart rate were analyzed under the condition of fixed vertical factor (20∼80cm), two horizontal factors (35cm, 55cm), and two weight factors (10kg, 25kg) 2 times per minute for each lifting task. Eight healthy male workers performed nine-step stretching exercises which were intensified back power at the L5/S1 disc for six months. After completion of the two trials, the results were compared. The results of this analysis show that EMG signals have more an effect on the weight than the horizontal factors similar to those analyzed previous study, and are decreased. Therefore, those exercises presented very efficient. Also, there are not statistically significant differences on the analysis result of heart rate between weight factors.
Volume Holographic Fingerprint Recognition System for Personal Identification
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 256~263
In this paper, we propose a volume holographic fingerprint recognition system based on optical correlator for personal identification. Optical correlator has high speed and parallel processing characteristics of optics. Matched filters are recorded into a volume hologram that can store data with high density, transfer them with high speed, and select a randomly chosen data element. The multiple reference images of database are prerecorded in a photorefractive crystal in the form of Fourier transform images, simply by passing the image displayed in a spatial light modulator through a Fourier transform lens. The angular multiplexing method for multiple holograms of database can be achieved by rotating the crystal by use of a step motor. Experimental results show that the proposed system can be used for the security verification system.
An Analysis of Safety Management for Accident Prevention of Small & Medium Sized Manufacturing Companies - Based on the Kyungpook -
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 264~270
Small & medium companies in Korea have a high frequency of industrial injuries. And among them, manufacturing companies are most severe on side of the frequence rate of injuries. In this study, the measures to improve the safety management system of small & medium sized manufacturing companies in 4 city of Kyungpook are sampled in accordance with the type of industrial and the scale. The current status of management system are also investigated by the questions and answers from safety manager of those companies. The results obtained by this study were the improvement of main factors(safety education & training, safety device, working environment, safety consciousness) for industrial accident prevention
A Study on the Effectiveness Raise of Industrial Safety Training
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 271~278
Every safety and health activity relies to some extent on education and training. Through effective education and training, people learn how to recognize safety and health hazards and how to control them. Thus, in most cases education and training is the first step in an accident prevention program. In this study, we analyzed safety training course-compare with Industrial Safety & Health Act, KISCO and KISA's rules,-and applied to workplace. In the safety training of workplace on the ground of the Industrial Safety & Health Act, the ratio of periodic employee refresher training to the total training subjects is only 25% and it of supervisor training is 16.7%. The ratio of training implemented in workplace about Knowledge, Skill, Attitude is as follows Periodic update training ; 15.1% : 7.5% : 64.2% New employees training ; 15.7% : 5.9% : 58.8% Job-change training ; 32.6% : 23.2% : 39.5% Specific safety & health training : 34.8% : 8.7% : 45.6%
Improvement of Investigation Items of Fatal Industrial Accidents Considering Human Error Characteristics
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 279~285
This study investigated human error characteristics of the 42 fatal industrial accidents reported by staff members of Korea Industrial Safety Corporation. Various types of human error were judged to be primary contributing factors in about 74 percent of the cases. Most of human error made by involved industrial operators resulted from two types of mistakes: (1) mistake in judgement of work situation, and (2) omission in daily check. It was concluded that preparation/observance for work procedure manuals, danger predication training and enforcement/Education of daily check routine would be effective preventive tools for these types of human error attributable to fatal industrial accidents.
A Test Verified Model Development Study for Seismic Qualification(Safety)
Uk-Hwan Sur ;
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 286~291
This paper includes discussion on developing the test verified finite element model for one of the seismic qualification(safety) approaches. It presents a test verified finite element model of a UPS(Uninterruptible Power Supply System) to be used at KMRR, KAERI. The test verified model predicts natural frequencies within 5 percent error for all major modes below 50Hz. This model accurately represents the dynamic characteristics of the actual hardware and is qualified for its use in the final stress analysis for seismic verification.
Size Effect in the Fracture Behavior of Reinforced Concrete Members
Kim, Dong-Baik ; Kim, Woon-Hak ; Paik, Shin-Won ;
Journal of the Korean Society of Safety , volume 13, issue 4, 1998, Pages 292~299
In this study, the size effect in flexural and shear behaviors of reinforced concrete beams with stirrup has been studied. The specimens of different size with same longitudinal reinforcement ratio are tested. The major variables of test include the size(relative depth) of the members as well as the longitudinal reinforcement ratios. The nominal resistances in flexure and shear are obtained for various sizes and steel ratios. It is found from the present study that the size effect is also very pronounced for the flexural resistance in reinforced concrete structures. The prediction formulas for the size effect of reinforced concrete beams in flexure and shear are proposed. The proposed equations agree relatively well with experimental data. The present study will provide useful bases for more accurate analysis and design of reinforced concrete structures.