배관 시스템은 기체 및 액체 등의 에너지원을 수송하기 위해 사용되며 주로 건물 내부에 설치되거나 지반에 매립되 어 설치된다. 매립된 배관 시스템은 지진이나 지반침하와 같은 큰 상대변위를 받을 수 있으며 이는 배관의 연결부에 손상을 야 기할 수 있다. 벨로우즈는 기하학적 특성으로 축방향 및 회전 변형을 일부 허용한다. 그러므로 벨로우즈 신축관이음을 적용하면 큰 상대변위에 의한 손상을 줄일 수 있는 것으로 예상된다. 하지만 벨로우즈의 성형과정에서 회선의 벽 두께 감소가 발생할 수 있으며 이는 휨 및 인장 성능에 영향을 미칠 수 있다. 본 연구는 단조하중을 받는 벨로우즈 신축관이음의 성능을 분석하기 위 한 실험적 연구를 수행하였다. 또한 단조하중 실험 결과를 바탕으로 벨로우즈 신축관이음의 유한요소모델을 구축하였으며 실험 결과와 비교하여 검증하였다. 검증된 유한요소 모델을 이용하여 회선의 두께 감소에 의한 성능 변화를 분석하였다. 벽 두께 감 소율은 5%, 10%, 15%, 20%, 25%로 가정하였다. 해석 결과 인장 및 휨 하중에 따른 하중-변위 관계의 전체적인 강성과 최대 하 중이 감소하는 것으로 나타났다. 벽 두께 감소율이 25%일 때 인장 및 휨 하중에 따른 최대 하중은 각각 14%, 26% 감소하는 것 으로 나타났다.

PURPOSES : In the case of a turning maneuver at an at-grade intersection or changing the driving path, the trajectory of a vehicle with a long body, such as a large bus or an articulated bus, should be analyzed from the perspective of road design. In this study, an articulated bus was selected to analyze the off-tracking, swept path width, and lane encroach hment for vehicle turning. METHODS : In this study, four scenarios were developed for right- and U-turn situations. For the right-turn situation, cases were divided into radii of 15 m (Scenario 1) and 40 m (Scenario 2). For the U-turn situation, the cases were analyzed based on a U-turn after stopping at the stop line (Scenario 3) and without stopping at the stop line for the U-turn (Scenario 4). Each scenario was examined at 5° (Right-turn) and 10° (U-turn) angles to analyze the off-tracking, swept path width, and lane encroachment. In addition, four Global Positioning System (GPS) antennas were installed on top of the articulated bus to obtain the driving trajectory of the vehicle. GPS locational reference points were marked on the testing ground to improve positioning accuracy. RESULTS : As a result of the right-turn analysis at an intersection radius of 15 m (Scenario 1), the average off-tracking per angle was 1.04 m, the average swept path width was 3.89 m, and the lane encroachments occurred at an angle of 65° to 70°. For the right-turn analysis at an intersection radius of 40 m (Scenario 2), the average off-tracking per angle was 3.71 m, and the average swept path width was 3.31 m. Unlike the results for the 15-m radius, no lane encroachment was found. Furthermore, the averages of the off-tracking in the at-grade intersection U-turn situation were 2.65 m (Scenario 3) and 2.54 m (Scenario 4), and the average swept path width was 6.15 m. CONCLUSIONS : The required driving width when an articulated bus performs a turning maneuver at an at-grade intersection was analyzed, revealing the implications that must be considered for busway design.

A long-term cooling effect on hydride reorientation of a cladding tube can affect the integrity of spent nuclear fuel transportation and long-term storage. In this study, experimental setup for investigating the degree of radial reorientation of hydrides in the circumferential direction during the long-term cooling was established. The experimental setup was designed to be simplified since the long-term evaluation requires a long term period such as 12, 18 and 24 months when the cladding tube specimen is gradually cooled down from 400°C to 100°C. For the test, hydrogen-charged specimens of 100 ppm, 200 ppm, and 500 ppm were prepared. The specimen was sealed with fixtures and check valve, and was pressurized up to 90 Mpa. To heat the specimen, a box-type furnace was used while the temperature of the specimen was measured from thermocouples attached to the specimen. After the heat treatment, the long-term cooling was performed by developing temperature control program to investigate several cooling rate conditions of the specimen. As a reference case, microstructure and brittle property of the hydrogen-charged specimens of 100 ppm, 200 ppm, and 500 ppm without the long-term cooling was observed. In the case of the hydrogen content, it was uniformly distributed in circumferential direction although it was non-uniform in the axial direction. In the case of the brittle property, a compression test was performed. For the future work, the microstructure and brittle property of the hydrogencharged specimens after the several long-cooling conditions were investigated. Then, the degree of radial reorientation of hydrides in the circumferential direction during the long-term cooling was studied.

대부분의 연구자들은 반응시간기반 숨긴정보검사(RT CIT)의 탐지 효율성을 평가하기 위하여 실험연구를 수행한다. 실험연구에서 거짓말하는 상황을 만들기 위하여 주로 두 가지 실험 패러다임이 사용된다. 한 가지는 모의 범죄 패러다임이며, 다른 한 가지는 개인적 항목 패러다임이다. 본 연구의 목적은 실험 패러다임에 관계없이 RT CIT의 탐지 효율성이 동일하게 추정되는지 검증하는 것이다. 연구 1에서는 선행 연구들에 대한 메타분석을 통하여 두 가지 실험 패러다임 간에 RT CIT의 효과크기가 다른지 검증하였다. 39개 연구에 대한 메타분석 결과, 모의 범죄 패러다임 의 효과크기(Hedges의 g=1.330)가 개인적 항목 패러다임의 효과크기(g=1.145) 보다 약간 컸지만, 통계적으로 유의한 차이는 아니었다. 연구 2에서는 모의 범죄 패러다임 조건과 개인적 항목 패러다임 조건을 포함하는 실험연구를 수행하여, 실험 패러다임에 따라 RT CIT의 탐지 효율성이 다른지 검증하였다. 변량분석 결과, 관련자극과 무관련자극 간의 반응시간 차이가 실험 패러다임에 따라 통계적으로 유의하게 다르지 않은 것으로 나타났다. 실험연구에서 모의 범죄 패러다임의 효과크기(Cohen의 d)는 1.638이었으며, 개인적 항목 패러다임의 효과크기는 1.535였다. RT CIT의 탐지 효율성이 실험 패러다임에 영향을 받지 않는 이유에 대하여 논의하였다.

AU(A plus U-shaped) composite beam was developed for reducing the story height in the residential buildings, and saving the cosrtuction cost of floor structures. Structural performance and economic feasibility of the composite beam have been sufficiently approved through the structural experiments and the analytical studies. Fire safety for the practical application of the composite beam has also been verified through the fire resistance tests and the heat transfer analyses. In this study 2-points bending tests were performed on the four specimens already tested for fire resistance to evaluate the residual bending strength of AU composite beam after fire accident. The same bending test was performed on the one fresh specimen having the same section and span of the specimens for practically comparative study.

In order to measure the filtration characteristics of a cotton ball shape filter, the experiments of suspended solids(SS) surrogate material selection and filtration performance have been carried out in this study. Between the two materials of powdered activated carbon(PAC) and powdered red-clay, PAC is more suitable surrogate material in terms of experimental criteria and particle size distribution in the non-point source pollutants removal system. As a result of the filtration experiments with the cotton ball shape filter, the initial headloss was about 8 cm, and the headloss slightly increased over filtration time. The Kozeny-Carman equation was used to analyze the changes of pressure and porosity during the filtration. The initial porosity was calculated as 0.945 and it decreased to 0.936 at the end of design filtration time. As the filtration continued, the SS concentration of the filtered water gradually increased and the SS removal rate gradually decreased. When the SS target removal efficiency is assumed to be 80%, the cumulative SS removal capacity is expected as 28.8 kg/m2. This means the volume loading rate of the cotton ball shape filter can be 115 m3/m2 when the typical SS concentration of non-point source water pollution is assumed as 250 mg/L.

The purpose of this study was to examine the relationship of fatigue and stress in seafarers. Ninety healthy adults were recruited and cumulative fatigue, stress index and stress resistance of seafarers were measured using autonomic nervous system analysis device (SA-6000; Medicoa Co. Ltd. Korea). The stress index had a significant correlation with the degree of resistance (p<.01). Cumulative fatigue and the stress index had a strong positive correlation (r=.781) with the stress resistance, cumulative fatigue had a strong negative correlation (r=.782) (p<0.01). Furthermore, the stress index had a strong negative correlation with the degree of resistance (r=.924) (p<.01). The present study indicate that there are significant correlation between the cumulative fatigue and stress index, cumulative fatigue and stress resistance, as well as stress index and stress resistance in the seafarers (p<.01).

The main objective of this research is to study feasibility for applying metal membrane to remove particles from air scouring membrane backwash water. Also, the research was conducted to investigate the influence of polyamine coagulation on floc growth in membrane backwash water as pretreatment for removal particles. From the results of experiments for evaluating the influence of polyamine coagulation on floc growth, it was investigated that particles in the rage of 2~50 μm grew up to 30~5,000 μm. In addition, all six metal membranes showed lower removal efficiency, which was 0.87~13.89%, in the case of no polyamine coagulant. On the other hand, in the case of injecting polyamine coagulant, those did extremely high efficiency in 56~92%. From the SEM(Scanning Electron Microscope) images of filtered wiremesh and metal foam membrane, sieve effects were predominant for liquid solid separation in wiremesh and adsorption and diffusion capture effects were predominant in metal foam membrane.

An experiment have been conducted to investigate the behavior of dredged fills on flexible containers (scale model geotextile tubes). The study was focused on the development of geotextile strain. The model geotextile tube is made of woven geotextile material. Results showed that during the dewatering stage, the tube height decreases and the tube width increases. This increases the density of the confined fill material and the tensile reaction of the tube. The compaction effect on top of the geotextile tube decreases as the tube height reduces. On the other hand, the confinement effect at the sides of the geotextile tube increases as the tensile reaction intensifies. As a result, The geotextile strain increases as the value of the coefficient of lateral pressure is increased.

In this study, uniaxial compression tests were performed to investigates the stress-strain relations of Double Skinned Composite Tubular Columns reinforced with steel tube. The confined concrete has been known as the strength of concrete increases significantly. Specimens reinforced with outer and inner steel tube were tested by uniaxial compression test. To investigate the influence of concrete strength increase by confining conditions in steel tubes, 8 specimens with different thickness of tube, hollowness ratio and concrete strength were tested and compared with other researcher's concrete material model.

According to a statistics, a number of traffic accident by bridge pier and independent fixed object crash accident has been increased. we evaluated a car damage and passenger injury through vehicle accident reconstruction test of independent fixed object crash accident. A damage of crash accident car based on accident investigation report was similar to demage of 27km/h reconstruction test car, and therefore we can find the speed of crash accident car is 20km/h～30km/h. It is very low that the skull fracture and injury possibility of AIS 4 above in 37km/h and 27km/h reconstruction test car. It is very high that injury possibility in 70km/h reconstruction test car. Also, it is not high that impact of the driver and passenger's lower body(thigh, shin, ankle) in 37km/h and 27km/h reconstruction test car. On the other hand, it is very high that impact of head, chest and thigh of the driver and passenger in 70km/h reconstruction test car.

본 연구에서는 교량기초 말뚝의 부주면마찰력 시험을 통하여 연약지반에 타설된 강관말뚝의 부주면마찰력을 측정하였으며 장기적인 마찰응력의 관측시험을 통하여 경제적인 상부구조물 시공시기를 판단하였다. 본 연구의 결론은 다음과 같다. (1) 연약지반에서 부마착력의 크기는 침하속도가 클수록 크게 나타났다. (2) 마찰력의 관계 그래프에서 마찰응력의 증감이 없는 시기를 확인하여 상부구조물 시공시기를 판단할 수 있었다. (3) 말뚝정재하시험결과와 부주면마찰력 시험결과를 비교해 본 결과 항타 직후의 부주면마찰력은 재하시험 시의 마찰응력보다 크게 나오는 것으로 판단되며 15일 경과후의 측정값은 비슷하게 나오는 것으로 판단되었고, 이론식에 의한 결과와도 비슷하였다. (4) 부주면마찰력의 장기관측기법을 사용하면 부주면마찰력이 발생하고 있는 중이라도 적절한 상부구조물의 시공시기를 파악할 수 있어 경제적인 시공관리가 가능한 것으로 판단된다.

원자력발전소(이하, 원전)에 설치되는 안전관련 전기기기들의 합리적인 내진검증을 위해서는 사전에 정확한 동특성분석이 필요하다. 이 연구에서는 원전에 설치되는 전기기기 캐비닛 구조를 대상으로 입력 진동의 수준에 따른 모드특성의 변화를 평가하였다. 이를 위해, 실제 전기기기 캐비닛을 시편으로 선정하고 가진 시험기를 이용하여 입력진동에너지의 크기를 변화시켜 가면서 진동시험을 수행하였다. 시험은 캐비닛의 문짝을 부착한 경우와 탈거한 경우로 구분하여 수행하였다. 진동시험을 통하여 계측된 시편의 가속도응답신호와 입력운동신호로부터 진동의 크기에 따라 진동수응답함수를 작성하였다. 다항식회귀분석기법을 이용한 모드분석기법으로 시편의 진동수응답함수를 분석하여 모드특성을 추출하고, 진동수준에 따른 시편의 동특성 변화를 검토하였다. 연구결과, 대상 기기는 입력진동의 크기가 증가할수록 모드진동수와 모드감쇠비가 비선형적으로 변화하는 것을 확인하였다. 문짝이 부착된 경우에는 문짝이 탈거된 경우에 비하여 캐비닛의 모드감쇠가 증가한다.

An evaluation of the concrete strength has very important meaning in the maintenance and the structural safety. The reliability of ferroconcrete building is weakening and enlarging the life is strongly demanded due to the early deterioration of concrete. Like this social demand, concrete strength presumption is being indirectly executed using the result in parallel with the concrete pouring by material age. This data is usually different as concrete poured practically and the way of hardening and curing. Although existing concrete strength presumption formula is proposed, the material used and the concrete strength is different. And as a matter of remicon, the concrete strength varies according to the site and the way of curing. So the objective of this research is strength evaluation of the structural body concrete according to the concrete pouring and curing temperature change seasonally after using the system which evaluates the structural body concrete strength which is applied the transparent junction-separation mold that is presented. Also there is an objective to present the fundamental data for the constructional quality technique proposal of the structural body concrete developed in relation to field specimen and the strength evaluation method by non-breaking.

This study aimεd to ìnvestigatε the relationship between phonemic awareness and listening comprehension ability. For this paπIC비ar research purpose thζ English name test and TOEFL LlC tests were employεd and a total of 34 university students participaκd in this εxpεriment. The English name tεst consisting of relativεly unheard 26 English namζs was specially dεsigned and adminisκrεd for the participants to depend on their own phonemic awarenεss ability, not applying their cognitive prior knowlεdge. whεn they transcribε:d the n잉nεs using the phonεtic alphabεts. Thε statistical result showed that thε Pearson's product-moment correlation coεfficient was .550* and its coefficient of determination was .303. This result c1ζarly demonstrated that the phonemic awareness ability was highly correlatεd with the overall Iistening comprεhension ability and implied thε need for implεmεnting the so-called bottom-up method for developing students' phonζrnic awareness ability at primary or secondary school levels.