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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 19, Issue 4 - Dec 2004
Volume 19, Issue 3 - Sep 2004
Volume 19, Issue 2 - Jun 2004
Volume 19, Issue 1 - Mar 2004
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Effect of Stress on the Polarization Characteristic of Al-brass
Lim, Uh-Joh ; Jeong, Hae-Kyoo ; Sim, Kyong-Tae ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 1~5
Al-brass is the raw material of mnufacturing tubes for heat exchanger of vessel where seawater is used to coolant because it has high level of heat coductivity and excellent mechanical properties and high level of corrosion resistance due to cuprous oxide(
) layer against seawater. However, damage of Al-brass tubes for heat exchanger of vessel is reported that local corrosion such as stress corrosion cracking occurred by synergism effect between mechanical factor and corrosion environment. In this study, to investigate on the effect of stress on the polarization characteristics of Al-brass. At the stress of 0% and 95% yield strength by constant displacement tester, in 3.5% NaCl + 0.1%
solution, the polarization tests were carried out. And thus open circuit potential, corrosion current density, anodic polarization, cyclic polarization and dezincification behavior of Al-brass are investigated.
Development of the Magnetic Abrasive Using Sludge
Kim, Hee-Nam ; Yun, Yeo-Kwon ; Kim, Sang-Baek ; Choi, Hee-Sung ; Ahn, Hyo-Jong ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 6~10
The magnetic polishing is the useful method to finish using magnetic power of magnet. This method is one of precision polishing techniques and has an aim of the clean technology using for the pure of gas and inside of the clean pipe for transportation. The magnetic abrasive polishing method is not so common for machine that it tis not spreaded widely. There are rarely researcher in this field because of non-effectiveness of magnetic abrasive. Therefore, in ths paper deals with development of the magnetic abrasive using sludge. In this development, abrasive grain WA and GC used to resin bond fabricated low temperature. And magnetic material was fabricated from the sludge which were crused into 200 mesh and average diameter
1.2mm ball type. The XRD analysis result show that only WA and GC abrasive and sludge crystal peaks detected which explains resin bond was not any more chemical reaction. From SEM analysis it tis found that WA and GC abrasive and sludge were stron bonding with each other by bond.
The Burst Pressure Analysis of Steam Generator Tubes with Inclined Type of Wear Damage
Shin, Kyu-In ; Park, Jai-Hak ; Chung, Myung-Jo ; Choi, Young-Hwan ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 11~15
The fretting-fatigue by leaking is one of the significant degradation in steam generator tubes. In this study, the burst pressure of inclined damaged steam generator tubes were obtained from three criterions by using the finite element method. The analysis results were also compared with the experiment data from published references and they showed a good agreement with the experiment data.
A Study on Evaluation of Crack Opening Point in Al 2024-T3 Material
Choi, Byung-Ki ; Jang, Kyeung-Cheun ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 16~20
This paper aims to analyze fatigue fracture mechnisms with high strength aluminum alloys, which are widely used in vehicles or airplanes to prevent accidents. Usefulness of the crack opening point was proposed by using an effective stress intensity facor when evaluating the fatigue crack propagaion rate. Therefore an exact crack opening ratio can be measured for a more exact fatigue crack propagation rate. It is found that the fatigue crack propagation rate was valid within the range of experimentation as an effective stress intensity factor. Summarizing the results are as follows in this paper ; (1) It is found that the value of the crack opening ratio is constant at the rear of the specimen, U'=0.25 at the crack mouth and U'=0.45 at the crack tip, respectively regardless of the stress ratio. (2) The crack opening ratio is different according to measurement locations. The crack opening ratio value was measured at the crack mouth by a clip gage or measured behind the specimen by a strain gage. It is found that the crack opening ratio value is more accurate that any other measuring test for evaluating the crack propagation ratio test by effective stress intensity factor.
A Study of Characteristics of the Wire-cut EDM Process in Aluminum Alloys
Lyu, Sung-Ki ; An, Soon-Geon ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 21~25
This study deals with the characteristics of wire-cut EDM(Electrical Discharge Machining)process in aluminum alloys. Besides 2 series and 7 series of aluminum alloys for aerospace applications, porous aluminum is tested, which is used for sound absorbing matherial and interior and exterior material of building. Jinyoung JW-30 wire cutting machine was used in this experiment. Tap wate passed a filter and ionization was used as the discharging solution. An immerision method was applied as a cooling method because it separates chips effectively and machinability is good even with low value of electric current. The speed of fabrication was estimated by measuring the travel distance of the work piece and time spent for the movement. As pulse-on-time increased the fabrication speed decreased. On the other hand, as peak voltage of peak current increased the fabrication speed increased. In general 7075 aluminum alloy resulted in higher fabrication speed.
Hazard Assessment by Electric Shock both on the Ground and in the Water
Kim, Doo-Hyun ; Kang, Dong-Kyu ; Lee, Jong-Ho ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 26~33
This study presents a hazard assessment of the human body exposed to electic shock considering various parameters which affect severity of the electric shock. The present study has two research objectives; one is no analyze hazards of the human body by the elctric shock both on the ground and in the water. The other is to understand the mechnism of the electric shock. In order to achieve these objectives the hazard of shock is estimated by comparing with physiological effects of electric curren througn the human body according to variation of shock parameters of shock circuits. The shock parameters adopted in this paper consist of body resistance, resistance of protective equipment, ground resistance, shock duration, depth of gound surface layer, relection factor, permissible touch voltage, body current and body voltage. Besides, safety standard determining hazard degree of the human body is introduced. And hazard of the human body due to the electric shock is quantitatibely assessed in consideration of data obtained by the method suggested herein, and final results are presented and discussed.
Analysis of SAR Distribution Characteristics in a Head Model using FDTD
Hong, Dong-Uk ; Kim, Doo-Hyun ; Kang, Dong-Kyu ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 34~40
This paper presents an analysis of SAR(Specific Absorption Rate) distribution characteristics in a head model using FDTD(Finite Difference Time Domain). In this study human head was modelled in four elements-layered structure, consisting of skin, fat, skull and brain. To calculate the electromagnetic fields wihtin the head model, FDTD method was used. In the FDTD method, the electromagnetic wave is analyzed by solving a Maxwell's equations repeatedly. For the calculation, distance between power source and head model increased by 10[m]. Power density and incident electric field intensity were calculated. Based on the incident electric field, the program which calaculated internal electric fields intensity and SAR calculation of the head model were developed. The results of developed program using FDTD were compared with those of a commericial programs, which showed the availability and usefulness of the suggested scheme in this paper.
Preparation and Properties of Rust-Removing Polymer Gel
Kang, Young-Goo ; Kim, Jeong-Hun ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 41~46
The formation of rust on metallic substrate is known to cause the damages and destructions of raw materials, which is one of the leading reasons of sturctural collapses and many kind of hazards in modern industry. Polymer gels with rust removing effects were compounded in this study by employing various kinds of acids like hydrochloric acid, phosphoric acid, gluconic acid, oxalic acid as the rust removing ingredients. TEA(Triethanolamine) as dispersant and hydrophilic chemical were used for effective gelation of acids. Also corrosion inhibitor was added to enable the coating effect and to improve rust removing effect on metallic surface. In order to investigate the rust properites on metallic substrate, artificial rusts were prepared in salt solution, using iron, copper, aluminium and brass as the base metals. The properties of gel compounds were checked by gelation, pH, viscosity, morphology property and rust removing test. Developed gel compounds in this study have a good rust removing property, showing a strong adhesion on horizontal and vertical metallic surface, and can be easily rinsed off by water.
A Study on Synthesis of Functional Composite Latex and Characteristics of Thermal Decomposition
Kwon, Jae-Beom ; Kim, Nam-Suk ; Lee, Nae-Woo ; Seul, Soo-Duck ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 47~53
Emulsion polymerization ws carried out using Alkyl methacrylate(RMA) like MMA, EMA, BMA and Styrene Monomer(SM) for core-shell latex preparation. It was synthesized at
in the presence of anionic surfactant SLS(Sodium Lauryl Sulfate). FT-IR and DSC analysis are used to confirm the synthesized core-shell emulsion latexes. Moreover DSC and TGA were used to investigate the thermal characterisitcs of them. The differences of the decomposition rate and the activation energy from TGA and DSC analysis are not so big. It considers that the pendent group is not affect of the thermal characteristics and stability on core-shell latexes, which is synthesized with RMA and Styrene. For investigating combustion products, LC50 values were calculated by FED(Fractional Effective Dose)from the Pyrolyzer-Mass sepctrometer.
Measurement and Prediction of Autoignition Temperature(AIT) of Flammable Substances - Methanol and Ethanol -
Ha, Dong-Myeong ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 54~60
Flammable substances are frequently used chemical industry processes. An accurate knowledge of the ALTs(Autoignition Temperatures) is important in developing appropriate prevention and control measures in industrial fire protection. The AITs describe the minimum temperature to which a substance must be heated, without the application of a flame or spark, which will cause that substance to ignite. The AITs are dependent upon many factors, namely initial temperature, pressure, volume, fuel/air stoichiometry, catalyst material, concentration of vapor, ignition delay. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for methanol and ethanol. The A.A.P.E.(Average Absolute Percent Error) and the A.A.D.(Average Absolute Deviation) of the experimental and the calculated delay times by the AITs for methanol were 14.59 and 1.76 respectively. Also the A.A.P.E. and the A.A.D. of the experimental and the calculated delay times by the ATIs for ethanol were 8.33 and 0.88.
Evaporation Characteristics of a Water Droplet Containing Sodium Acetate Trihydrate as an Additive
Park, Jae-Man ; Shin, Chang-Sub ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 61~68
The evaporation phenomena of waterr droplet which has sodium acetate trihydrate(
) as a fire suppression additive were studied. Solutions of sodium salt up to 50% and heated stainless-steel surface were used in the experiment. The evaporation process was recorded using a charge-coupled-device camera at 120 frames per second. The average evaporation rate of the sodium acetate trihydrate soluation was lower than that of pure water at a given surface temperature and decreased with the concentration increase due to the precipitation of salt in the liquid film and change of surface tension. The variation of liquied film diameter was measured by time and it was increased by the hot surface temperature increase.
Performance Assessment Model for Fire Safety Protection of Office Building
Yang, Eun-Bum ; Hwang, Young-Sam ; Lee, Chan-Sik ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 69~74
This study is to suggest a performance assessment model for fire safety protection of office building 34 asessment elements were chosen by interviewing with experts, reviewing several codes and existing relevant models, assessment elements included in this model are comprised of five categories which are 'performace of protected area', 'performance of fire partition', 'safety performance of fire escape', 'performace of smoke control system' and 'performace of fire fighting equipment'. The weight of each element was computed by systematic approach like an AHP (analytical hierarchy process), which was conducted by experts who work in the field of fire protection. This model would be utilized as a part of assessment model for the overall performace of domestic office building.
A Field Survey on the Development of Safety Management Information System in the Construction Management
Kim, Young-Soo ; Park, Jong-Keun ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 75~87
This study suggests a safety management model for construction management (CM) suitable to domestic conditions so that inefficiency resulted from the operation of construction projects by public and private indtitutes according to different systems can be eliminated for the securing of systematic and efficient safety managment. Based on the suggested safety management model, this study also develops a safety management information system that can efficiently and consistently manage and maintain a large quantity of information, and give necessary supports in a speedy way in the managing of construction projects.
The Analysis of the Slope Stability for the Small Dam
Choi, Ki-Bong ; Bae, Woo-Soek ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 88~92
The paper decribes a procedure for the evaluation of the effect of seepage force on stability of slopes. The stability of an embankment impounding a water reservoir is highly depend upon the location of seepage line with the embankment. To evaluate the accurate safety factor of an embankment, it is important to illustrate the seepage phenomenon. Of particular interest is the stability following a rapid change of reservoir level. Seepage forces in embankments are easily determined interest is the stability following a rapid change of resrvoir level. Seepage forces in embankments are easily detemined if frictional forces are expressed in relation to hydraulic gradient I. If a piezometer is inserted into a body of embankment, the level to which fee water rises is a measure of the energy at that point.
A Study on the Strength Change of Used Pipe Support (1)
Paik, Shin-Won ; Ro, Min-Lae ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 93~97
Slab formwork consists of sheathing, stringer, hanger and shore. There are several types of adjustable individual shores. In constructions site, pipe supports are usually used as shores. The strength of a pipe support is decreasing as it is frequently being used at the construction site. In this study, 2857 pipe supports were bought to fine out the strength change of used pipe support and unused pipe supports according to aging. Among these pipe supports, 2337 pipe supports were lent to the construction companies free of charge. Compressive strength was measured by knife edge test and plate test at each 3 month. Test results show that the strength of unused pipe supports almost equaled to the strength of new pipe supports until 191 days, but the strength of used pipe supports at 191 days was lower than the strength of new pipe supports. So, the strength of used pipe supports at 191 days was not satisfied the specification of KS F 8001. According to these results, it shows that attention has to be paid to formwork design using used pipe supports. Therefore, the paresent study results will be able to provide a firm base to design slab formwork and test the performance of used temporary structure and prevent formwork collapses.
An Experimental Study on the Effect of Mineral Admixtures for the Durability of Shotcrete
Paik, Shin-Won ; Chung, Dok-Chu ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 98~103
Shotcrete needs the enough durability without deterioration for life time. But shotcrete is being deteriorated according to aging like concrete by internal causes whithin itself and by external causes which can be physical, chemical, or mechanical. Durable shotcrete can be made by incresing the cement content, adding chemical and mineral admixtures and so on. So, in this study, chloride ion penetration test, freeze and thaw test, neutralization test were conducted to examine the durability characteristice of shotcrete with mineral admixtures such as silica fume, blast-furnace slag and fly ash. These results indicate that shotcrete with silica fume is durable. Therefore, the present study provides a firm base to make high performance shtcrete.
The Influence of Inorganic Pigments on the Compressive Strength and Absorption of Cement Mortars
Shon, Hyuk ; Lee, Jae-Yong ; Go, Seong-Seok ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 104~111
The aim of this study was to investigate the influence of inorganic pigments on the physical properties of cement mortar. For this purpose, the compressive strength and absorption test were carried out on cement mortar imxed with inorganic pigments by changing the proportion of cement mortar, water-cement ratio, and ratio of pigment. The result of this study can be summarized as follows: the compressive strength of colored mortar rapidely increased in red and yellow mortar, as the mix ratio of pigment increased. In case of green and black mortar, however, the compressive strength decresed as the mix ratio incresed. In case of red and yellow mortar, the absorption of colored mortar increased as the mixing ratio increased, if the mean particle diameter of the pigment is small. In case of green and black mortar, the absorption ratio decreased as the mix ratio increased. After investigating the overall physical properties of colored mortar, it was confirmed that the proper mix ratio of pigment securing the properties of colored mortar was below 6% of the weight of the cement to be used.
Comparison of Displacement of the Braced Retaining Wall by Developed Elasto-Plastic Analysis
Shin, Jin-Whan ; Kim, Dong-Shin ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 112~118
Recently, when being constructed the large structures, the deep excavations have performed to utilize the underground space. As the ground excavation is deeper, the damage of the adjacent structure and the ground is frequently occurred. the Analysis of the retaining structures is necessary to safety of the excavation works. There are many methods such as elasto-plastic theory, FEM, and FDM to analyze the displacement of the retaining structure. In this thesis, GEBA-1 program by the Nakamura-Nakajawa elasto-plastic method was developed. The lateral displacement of the wall was analyzed by the developed program GEBA-1, SUNEX, and EXCAD, and compared with the measured displacement bye the Inclinometer. The monitored fields were three excavation work site in S-I, S-II, and S-III area. Excavation method of each site is braced retaining wall using H-pile. Excavation depth is 14m, 14m, and 8.2m.
Dynamic Behavior of a Long-Span Bridge Considering Soil-Structure Interaction
Lim, Che-Min ; Park, Jang-Ho ; Shin, Yung-Seok ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 119~124
The effect of soil-structure interaction becomes important in the design of civil structures such as long-span bridges, which are constructed in the site composed of soft soil. Many methodologies have been developed to account for the proper consideration of soil-structure interaction effect. However, it is difficult to estimate soil-structure interaction effect accurately becaused of many uncertainties. This paper presents the results of study on soil-structure interaction and dynamic response of a long-span bridge designed in the site composed of soft soil. The effect of the soft soil was evaluated by the use of computer program SASSI and a long-span bridge structure was modeled by finite elements. Dynamic response characteristics of a long-span bridge considering soil-structure interaction wereinvestigated.
Experimental Study on Interface Shear Strength of Concrete in Vertical Construction Joint
Kim, Ook-Jong ; Kim, Young-Chan ;
Journal of the Korean Society of Safety , volume 19, issue 2, 2004, Pages 125~129
In masive concrete placement, cracking problem due to hydration heat is frequently encountered. One of measure to solve this problem is to make a construction joint. However, it is cumbersome to make it by chipping the surface of joint. In this study, push-out test for 18 specimens was conducted to compare the interface shear strength of consturction joints whose surfaces were prepared with three methods; chipping, rib-lath, folded rib-lath. Compared to the specimens made with conventional surface chipping, those with rib-lathe showd excellent preformance increasing shear resistance capacity and the role of shear key conceived by folding rib-lath played important role in enhancing shear resistance.