It is well known that pipelines have the highest capacity and are the safest and least environmentally disruptive form of transporting oil and gas. However, pipeline damage caused by both internal and external corrosion is a major concern threatening the reliability of oil and gas transportation and the soundness of the pipeline structure. In this study, we estimate the allowable damage by comparing the ASTM B31G code to a modified theory considering diverse detailed corrosive forms. The ASTM B31 G code has been developed as the evaluation method for reliability and incident prevention of damaged pipelines based on the amount of loss due to corrosion and the yield strength of materials. Furthermore, we suggest a method for estimating the expected life span of used pipelines by utilizing the reliability method based on major variables such as the depth and length of damage and the corrosion rate affecting the life expectancy of the pipelines.

A Problem of low-velocity forced convection in a channel flow with heated wall is of practical importance and widely considered in the design of devices such as heat exchangers, and electronic equipments. Therefore, there is an urgent need for improving heat transfer performance of heated wall in the channel. In the present study, an oscillating vortex generator method is proposed to enhance the heat transfer in a channel. In this method, a rectangular bars are set in the upstream of heated region of the channel. The bars are forced to oscillate normal to the inflow, and then actively and largely generates transverse vortices behind the bars. As a result, this apparatus can enhance the heat transfer rates remarkably. Because of the interaction between the flow and oscillating bars, the variations of the flow and thermal fields become time-dependent state.

The railroad bogie's components experience repeated loading during service. Especially, oil damper bush has been fatigue fractured on the plane between rubber and steel stem during service, and which results in inferior of performance of the bogie. In this study, in order to offer a proper maintenance method of the bush, bubber bush used for the oil damper was fatigue tested and its damage fraction during service was estimated. Also, FEM analysis on the bush was conducted. When 1400, 1200, and 1000kgf of repeated loads were applied to the oil damper bush, final damage fraction exhibited 63.7%, 50% and 40%. From the results of FEM analysis, deformation energy density was found to be $0.5452kgf/mm^{2}$ at an applied load of 1400kgf and the location with maximum value coincided with the fractured location of the bush. Finally, it will be desirable to adopt the normalized damage fraction rather than absolute damage fraction in estimating remaining service lifetime of the bush.

This paper presents assessment of possibility on the human risk for the electromagnetic field of unbalanced two coupled three-phase transmission line using fuzzy theory. Three phase load flow program was developed which employed a Newton-Raphson method as a tool to analyze system unbalanced. This research presents a method of handling two coupled three phase transmission system unbalance analysis and unbalanced power demand as a function of voltages. As the results of case study, in case of 345[kV] T/L, the electric field intensity was 10.9540[kV/m], magnetic field intensity was 0.2567[G] in severest case. The results showed that the membership of a proposition fuzzy '10.9540 [kV/m] is hazardous' is 0.6349. As the analytic results using the fuzzy qualifier term, the membership in case of very false is 0.1379 and fairly false is 0.6124, respectively. In assessment of fuzzy measure possibility for the electromagnetic field, this paper used probability of fuzzy arid measure of fuzziness technique.

It is revealed that these are correlated with the height of chamber deciding the turbulence extent. In the first experiment, It was examined about the effects of different multiple obstacles such as circular, triangular and square things with the rig that the dimension of original experimental rig was $700{\times}700{\times}200mm{\wedge}3$. Then the heights of chamber were increased from 200 to 1000mm. The dimensions of each obstacle were $70{\times}700{\times}{\wedge}2$ and rectangular vent area were $210{\times}700{\times}{\wedge}2$. In the second one, we performed to see the effects of locations of different multiple obstacles in 200, 500 and 800mm height from the bottom. The results are : The multiple triangular obstacles caused the highest overpressure while the lowest one was the multiple circle bars. Then, the triangular bars caused the highest flame acceleration while the circular obstacles was lowest too. The results showed that the critical height was 800mm due to the formation of turbulence. And the lesser $Av/V^{2/3}$ were small, the more pressure and pressure acceleration rate were increased.

Cobalt catalysts for gas mask loaded on various supports such as $Al_{2}O_{3},\;TiO_{2}$, AC(activated carbon) and $SiO_{2}$ were used to examine influences of calcination temperatures and reaction temperatures for CO oxidation. $Co(NO_{3})_2{\cdot}6H_{2}O$ was used as cobalt precursor and the catalysts were prepared by incipient wetness impregnation. The catalysts were characterized using XRD, TGA/DTA, TEM, $N_{2}$ sorption, and XPS. For the catalytic activity, support was in the order of ${\gamma}-Al_{2}O_{3}>TiO_{2}>SiO_{2}>AC\;and\;Al_{2}O_{3}$. The catalytic activity at lower temperature than $80^{\circ}C$ showed that with the increase of reaction temperature, cobalt catalysts on ${\gamma}-Al_{2}O_{3},\;TiO_{2},\;AC\$ has the negative activation energy but that of $SiO_{2}$ was positive.

The smoke exhaust system is one of the effective systems to save lives when fire occurs underground. This study presents a complete analysis of effective smoke exhaust and smoke characteristics for a fire occurring with a transverse ventilation system use as a smoke exhaust system. The performance of the smoke management system was studied by computer modeling using FDS version 3.1. A fire size of 20MW was used for tunnel with balanced exhaust transverse ventilation. The smoke management design and the procedure as simulated in this study are also compliant to the tunnel construction and fire codes of Korea.

This paper describes the methods for the detection of shorted-turn in the rotor of a cylindrical synchronous generator. A search coil is installed in the air-gap to detect the shorted-turn. The occurrence of a fault in the rotor winding results in a decrease of the induced voltages in the stator. And the magnitude of the rotor flux can be estimated by using the search coil and the estimated stator voltages respectively. And the magnitude of the estimated rotor flux is used for discriminating the rotor windings short or not by detecting the magnitude of the rotor flux. The method using a search coil located in the air-gap can detect not only the occurrence of a turn fault but also its position in the rotor winding. But the method using the estimated stator voltages gives the magnitude of the rotor flux, and only the number of a short-turn.

Recent trends in the construction of building frame feature the use of composite steel concrete members. One of such system, RCS(Reinforced Concrete column and Steel beam) system, is known as a type of system to maximize the structural and economic benefits in the most efficient manner. This paper is focusing on an study of ultimate shear strength estimation of the interior beam-column joints of RCS system, with reinforced concrete column and steel beam. Current design methods as well as the majority of the previous researches for ultimate shear strength of the interior beam-column joint of RCS system are not easy to apply actual manner. There is a need to propose the rational macro models based on analytical approach. In this study, design method variables for interior beam-column joints of RCS system is studied assuming shear resistance of steel web panel, diagonal concrete strut mechanism and truss mechanism. Finally, calculated results based on the proposed design model are compared with test data.

The main purpose of this study is to present the strategies for strengthening the leadership of field supervisors to effectively prevent construction accidents. To this end, first, this research study reviewed the meanings, functions, types and characteristics of the leadership of field supervisors in safety management activities on construction sites through the literature review. Second, the researcher investigated the types of supervisors' leadership and the level of field safety management activities through questionnaires. Third, the types of supervisors' leadership are categorized by that level. Fourth, the leadership type of field supervisors is suggested to effectively prevent construction accidents. Finally, the strategies to promote supervisors' leadership are developed.

many plumbing system are needed in the ceiling of the building as it becomes advanced more and more. This leads to make effective space between ceiling level and slab less. Also, piping system is not suitably arranged and operated if it is bent around the columns which they are a lot. But this system can be more effective if it passes through the columns directly. Most people think that those columns should not be damaged with such as holes. But actually this is existed in a hotel building in switzerland. This study is to fing out how much capacity the columns become damaged and low using model size of $20cm{\times}30cm$ rectangular section, and 160cm long, in the structural test. it's compressive strength is focused on $240kg/cm^{2}$ design strength, commonly used in korea. Compressive test for them was done at Hanyang University using UTM one thousand tone(1000t) capacity. Variable numbers for the study are one hole of dia 3cm with distance 20cm or 40cm, two holes of dia 3cm with 20cm and 40cm distance, one hole of dia 5cm with distance 20cm and 40cm, two holes of dia 5cm with 20cm and 40cm distance, me eccentric hole with 20cm and 40cm distance, Normal(without hole). two test specimens of each variable are made for the test. ED5H20 capacity was 16.7% decreased, compared to normal one. While ED5H40 distant 40cm from the end of column top showed 19.5% capacity decrease, compared to normal one. Strain of ED5H20 diameter 5cm, in distance of 20cm form the top of the column was less 5% than the one of diameter 3cm. Finally, conclusions are that in case of hole diameter 3cm, located at 20cm from the end of the column top, capacity was decreased down to 3, percent only compared to the same diameter hole with 20cm distant from the end of it.

In the present study damage behavior of resilient sleepers on concrete ballasts is analyzed. Cracks of resilient sleepers in a railway track system are concentrated on inside of blocks to which the tie bars are connected. Finite element analysis is performed by dividing a block into the straight section and the curved section according to the load condition of the resilient sleeper, and limited the interpretation within the range of resilience. In addition, the value of stress obtained from the interpretation was compared with the allowable stress of concrete to determine the safety. According to the result of numerical analysis, compared with the stress before unequal settlement, the tensile stress of the inside of the block increased significantly after the settlement considering the entire block, and the tensile stress of this part exceeded the allowable stress of concrete, so was undesirable in terms of safety. In reality, the arrangement of tensile stiffeners inside blocks connected to tie bars is improper in the design of resilient sleepers, and when unequal settlement occurs, tensile stress increases on this part and consequently causes cracking damage. It is necessary to arrange wire meshes or tensile reinforcing bars in a structurally safe way to reinforce the inside of blocks on which cracks are concentrated.

Recently, experimental and theoretical studies about nonlinear behavior of large concrete structures are in progress. The purpose of this study is to describe the nonlinear behavior of a concrete specimen under compression using several plastic models and to choose the best plastic model for later use in numerical analyses of concrete structures. ABAQUS is a general-purpose FEM program and we tested all suitable embedded material models for concrete. To verify the effectiveness of nonlinear analyses, results were compared with uniaxial and triaxial compression test results.

The substructure of temporary bridges used during the construction period of main bridges needs to be simple and strong at the same time so that it doesn't block running water. When the water flow is hindered by sub-structure of the bridges, as it happens when H beams with bracing are used, either the water floods or the bridge gets damaged. Therefore, using round beams for the substructure and connect them together is a preventive choice considering the intensive raining in the summer. The bridges using round beams for the substructure have also benefited by fast construction because of fewer bracing and in-situ welding. Because the round-pile-connecting method is relatively new, the safety evaluation of the constructed bridge is an essential procedure before being used in the field. The field evaluation of a bridge including the vehicle loading test and moving load analysis has been conducted and the results showed the safety requirement is satisfied.

Earthquake motion is one of the most significant influence factors on the slope stability. In this paper, an effective stress analysis with the elasto-plastic model was carried out to investigate the behavior of the slope stability subjected to the successive two strong earthquake motions, fore and main shock. The major influence of fore shock to the slope stability was considered as the existence of the residual excess pore water pressure. The paper presents the influence of the existence of the fore shock to slope stability using the numerical analyses. In conclusion, the excess pore pressure by the fore shock was not dissipated during the 7hrs of consolidation. By this residual excess pore water pressure, the factor of safety at the sliding face showed the minimum values, and the deformations of slope was large when compared with the case that considered the main shock only. Furthermore, the minimum of the factor of safety came out after the end of the earthquake motion.

Inspection works are mainly carried out with the help of human sensory organs and are relatively simple and repetitive, so that the workers easily become to feel fatigue and monotony, and their mental activity levels attenuate. Consequently, during the work time, it is natural that various lighting conditions around the workplaces may have in-fluence on work performance. This study aimed to analyze cortical fatigue of inspection workers. Thus, an inspection work was simulated on a computer monitor under various lighting conditions, and CFF, EEG, EOG, and HRV were analyzed. According to the results, fatigue symptoms turned up about $60{\sim}90$ minutes after the onset of the work. The work performance also decreased when the fatigue symptoms due to lighting conditions turned up. The variations of fatigue and work performance were affected by illuminators, illumination levels, or interaction of those two factors. The spiral fluorescent lamp seemed improper to the inspection work, because the work performance under that condition was lower than under any other illuminators.

Nursing often requires heavy physical work activities such as lifting heavy loads, working in awkward postures, transferring patients, operating hazardous equipment, etc. Among various nursing tasks, patients transferring is one of the most physically demanding tasks. This study aims to investigate workload of the patients transferring, and to propose its improving methods for reducing high workload. The results showed that irrespective of methods for patients transferring and the number of workers involved, workload for most patients transferring tasks exceeded the action limit represented in terms of L5/SI compressive force of 3,400N or LI of 1.0 by NIOSH. The loads for some tasks were far larger than the maximum permissible limit of 6,400N. It is recommended that the mechanical devices for transferring patients such as ceiling crane, sling lift etc. should be introduced rather than simply increasing the number of workers in the tasks.

Traffic accidents occur due to complex influences of transportation companies, drivers, and road environment. This study found that education and surroundings for transportation companies, driving habits of drivers, and road safety facilities and accessory facilities were main factors that affected strongly traffic accidents. Also, it found that driving habits of drivers could affect accidents heavily more than two other factors. Road safety and accessory facilities were analysed that they affected traffic accidents independently with transportation companies and their own drivers. Therefore, in order to achieve a traffic accident prevention as our main target, those companies need to produce atmosphere that their own drivers can have safety awareness, and related institutions for the above target should run parallel with policy assistance and strict traffic enforcement. In the end, this study suggests that transportation companies should secure manpower wholly being charged with traffic safety and financial resources investing in it.

직업성 천식은 시안화물의 폭로에 의해 발생되는 것으로 알려져 있다. 남호주에 있는 가구산업에서는 일반적으로 목재판 위를 피복하기 위해 이중분사도포를 할 때 이소시안화물 도포제가 사용된다. 이 연구는 이와 관련 된 분야의 자료부족으로 관련 산업에서의 환경 및 피부와 안구폭로에 대한 모니터링을 위하여 수행되었다. 이 연구결과에 의하면 저압다량(HVLP)의 분사기 사용, 페인트 용액중의 저농도 경화제 및 전면 호흡보호구와 같은 적절한 보호구의 사용시에는 대기로부터 오염물질의 유입은 거의 없었고, 분사실 주변의 일반적인 작업범위에도 HDI 가 거의 감지되지 않았다. 페인트분사시의 일회용 장갑착용으로 피부폭로는 발견되지 않았으나, 칼라 모니터링에 의하면 장갑을 착용하지 않거나 청결하게 관리할 수 있는 공정이나 안전한 장소에 보관하지 않으면 작업장으로부터 피부폭로가 있었다. 페인트분사로부터 눈의 오염은 감지되지 않았고, 호흡기, 피부 및 안구에도 폭로되지 않았으며 유입과 가장 관련성이 있는 것은 작업형태이다.

본 논문은 2차원 동적 진동문제를 공간-시간 유한요소법으로 해석하고 있다. 공간-시간 유한요소법은 공간만 분할하는 재래식 유한요소해석에 비해 보다 해를 빠르고 쉽게 얻을 수 있다. 상대적으로 큰 시간간격에 대해서 공간과 시간을 동시에 분할하는 공간-시간 유한요소 근사법을 제시한다. 가중잔차법으로 공간-시간 영역에 대해 유한요소법을 정식화하였으며 선형 사변형 공간-시간 유한요소를 선택하여 해의 안정성에 관하여 언급하였다. 일반적 동적문제에서는 상대적인 큰 시간간격으로 인하여 해의 불안정을 야기 시키고 있으나 본 연구에서는 수치의 안정성을 보여주고 있다. 비구조 공간-시간 유한요소법은 재래식 수치해석에서 흔히 발생하는 해의 불안정성에 대한 결점을 보완함은 물론 효과적인 계산방법을 지니고 있다. 이 방법의 효율성을 위해 수치예제들을 제시하였다.

새건물증후군이란 새로 지은 건물에서 생활하는 사람들에게 눈이 따갑거나 목이나 코가 아프거나, 두통, 구토, 피부발진 등 증상이 나타나는 것을 일컫는 말이다. 새집증후군 원인물질의 주요 성분으로는 건축 자재나 벽지, 페인트, 가구 접착제 등에서 발생되는 포름알데이드(HCHO)와 톨루엔 등 휘발성 유기화합물(VOCs: Volatile Oragnic Compounds), 부유 박테리아, 곰팡이, 바이러스 등이다. 새집증후군을 저감하기 위한 방법으로는 환기에 의한 방법, 오염물질이 없는 친환경 재료의 사용 및 재료의 처리를 통해 오염물질을 저감하고자 제거하는 방법이 있다. 본 연구는 이들 방법 중 건축 재료 위에 표면코팅처리를 함으로써 실내 공기질을 향상시키기 위한 것으로, 건물 내 표면 코팅 전후의 공기질을 분석함으로써 실내 거주환경을 안전하게 조성하는 데 그 목적이 있다.