• 한국화재소방학회논문지
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• 제21권1호
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• pp.98-105
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• 2007

본 연구에서는 소방 건축분야에 가장 많이 사용되는 배관인 배관용 탄소강관 및 이에 상응하는 스테인리스 강관을 분기배관으로 제작이 가능한지 여부를 상용유한요소프로그램(ABAQUS)을 이용하여 확인하였다. 이러한 배관을 분기배관으로 성형할 경우 심이 없는 배관 사용을 원칙으로 하고 배관에 심이 있는 경우 심과 정반대방향을 성형면으로 하여야 한다. 배관의 성형시 플러그의 경사면과 길이가 성형에 가장 큰 영향을 미치는 요소임을 알 수 있었다. 분기배관의 성형해석결과를 토대로 분기부분의 최소 높이와 두께를 제안했다.

• 한국화재소방학회논문지
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• 제21권2호
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• pp.36-41
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• 2007

본 연구에서는 분기배관의 강도해석을 통해 분기배관이 화재안전기준상에서 사용할 수 있는지를 판단하였다. 그 판단 방법으로 상용유한요소프로그램(ABACUS)를 사용하였고, 강도해석결과를 증명하기 위해 해당 분기배관에 본체강도시험을 실시하였다. 그 결과를 통해 분기배관의 사용가능성을 확인하였다. 또한, 분기배관으로 가장 많이 사용되는 배관인 배관용 탄소강관(KS D 3507)과 같은 용도로 사용할 수 있는 스테인리스배관이 KS D 3576(배관용 스테인리스 강관) 10S임을 확인하여 스테인리스배관이 소화배관에 적용될 수 있도록 하였다.

• 대한조선학회 특별논문집
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• 대한조선학회 2013년도 특별논문집
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• pp.21-29
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• 2013

For the purpose of supporting Curved Blocks, pipe welding is commonly used on Curved panel. Typically, when it comes to attaching supporting pipe on heavy incurvated surface, it makes much loss in the process of design, cutting, welding. This paper gives proper methods to collecting problems and Core conflicts surrounding Support Pipe by using of TOC (Theory Of Constraints). Therefore drawing two solutions, pipe development program and NC generating from pipe development Data for Plate Cutting machine. It describes a process of erasing loss surrounding Support Pipe with "TOC Thinking process" and development of two programs in this paper.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.528-533
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• 2005

This paper presents the study of flows at T-junction pipe with orifices. Experiments were carried out for several flow rates, orifice sizes, and pressure differences. Numerical simulations were also done to get more data for the wide range of flow rates. Experimental results and numerical ones are in a good agreement. Due to the effect of T-junction part, the flow rates at the lateral pipe are greater than those at straight pipe for the same pressure differences. When orifices were added, the effects of T-junction part on the ratio of flow rates and the ratio of loss coefficients reduced.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.345-350
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• 2001

In order to perform elastic-plastic fracture mechanical analyses, fracture resistance curves for concerned materials are required. 1T-CT specimen was used to obtain fracture resistance curves. But the fracture resistance curve by the 1T-CT specimen was very conservative to evaluate the integrity of the structure. And fracture resistance curve was affected by the specimen geometry and crack plane orientation. The objective of this paper is to be certain the conservativeness of the fracture resistance curve by the 1T-CT specimen and to provide the additional safety margin. For these, the fracture tests using the real pipe specimen and standard 1T-CT specimen test were performed. 4-point bending jig was manufactured for pipe test and direct current potential drop method was used to measure the crack extension and length for pipe test. From the pipe and the 1T-CT specimen test results, it was observed that the J-integral of the 1T-CT specimen test at the crack initiation point was very small compare to that of the pipe specimen test.

• 동력기계공학회지
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• 제9권4호
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• pp.39-44
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• 2005

This paper presents the study of flows at T-junction pipe with orifices. Experiments were carried out for several flow rates, orifice sizes, and pressure differences. Numerical simulations were also done to get more data for the wide range of flow rates. Experimental results and numerical ones are in a good agreement. Due to the effect of T-junction part, the flow rates at the lateral pipe are greater than those at straight pipe for the same pressure differences. When orifices were added, the effects of T-junction part on the ratio of flow rates and the ratio of loss coefficients reduced.

• 한국터널지하공간학회 논문집
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• 제26권3호
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• pp.243-254
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• 2024

현재 국내 지역의 산업 발달로 인해 주요 도심은 물론 주변 도시 지역에도 건축물이 포화 상태이다. 이에 따라 사람들의 관심은 지하공간으로 쏠리게 되었고, 특히 도시개발에 있어서 터널은 광범위하게 활용되고 있다. 이에 따라 터널 및 터널굴착공법에 대한 연구가 활발히 진행되고 있다. 그러나 이수식 쉴드 TBM 사용 시 슬러지 배출관의 마모 및 파손 문제에 대한 연구는 부족한 실정이다. 따라서 본 논문에서는 기존 슬러지 배출관에 사용된 L자형 곡관을 T자형 곡관으로 변형하여 슬러지를 이동시켰다. 그 결과, L자형 곡관에 비하여 T자형 곡관이 슬러지 배출 시 곡관에 미치는 영향이 감소하는 것을 확인할 수 있었다. 이러한 결과를 바탕으로 이수식 쉴드 TBM 장비 사용 시 T자형 곡관을 사용하면 슬러지 배출관의 마모를 최소화할 수 있을 것으로 기대된다. 이는 결국 터널 공사 시 곡관 교체나 추가 용접에 따른 비용을 절감하는 등 경제적 이익으로 이어질 것으로 기대된다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권11호
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• pp.4615-4621
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• 2015

Background: The popularity of the water pipe, also referred to as hookah, narghile, shisha or hubble-bubble, has increased tremendously during the past few decades. This study was conducted to determine student water pipe smoking status and perceptions about the effects of water pipe smoking on health in a state university in Ankara. Materials and Methods: This cross-sectional study was conducted between September 2014 and January 2015. The data were collected with a questionnaire and "The Scale of Perception about the Effects of Water Pipe Smoking on Health". The data obtained were evaluated in IBM SPSS (version 20.0) statistical package program in computer. One-way analysis of variance (ANOVA) was used for the analyses by checking homogeneity of variances and Student's t-test. Values of p<0.05 were considered statistically significant. Results: The total mean score obtained by young people who took part in the study was determined as ($\bar{X}=65.20{\pm}1.25$, min=33, max=75). Upon comparison of the total mean scores obtained by young people from the Scale of Perception about the effects of water pipe smoking on health and gender variable, the scores obtained by the females students were higher than those of the male students with a statistically significant difference (t=7.525, p<0.05). A statistically significant difference was observed between the total mean scores obtained by young people with cigarette and water pipe smoking status (for each, t=-3.731, p<0.05; t=-13.987, p<0.05). Conclusions: In conclusion, university students have wrong knowledge on the dangers of water pipe smoking. There was a high prevalence of using water pipes among university students. Gender significantly affected the perceptions about the effect of water pipe smoking on health in our sample.

• 소성∙가공
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• 제24권5호
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• pp.317-322
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• 2015

A process for the concurrent welding and extruding of pipe was designed for continuous production of fin tubes. Unlike a conventional pipe extrusion, the new process is able to extrude a pipe continuously without limit of length by using spring type wire material. The current paper provides the basic research for welding during the extrusion using a spring type wire material. The object of the current study is to investigate the possibility that the spring type wire material could be extrude into a welded pipe. The appropriate extrusion ratio was selected through investigation of loads using computer simulations. As a result, experiments showed that pipe could be welded and simultaneously extruded with spring type wire material of aluminum. The tensile strength of the welded and extruded aluminum pipe can reach 80% of tensile strength of original aluminum feedstock.

• Steel and Composite Structures
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• 제38권2호
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• pp.151-164
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• 2021

During the pipe forming process, a steel plate undergoes inelastic behavior multiple times under a load condition repeating tension and compression in the circumferential direction. It derives local reduction or increase of yield strength within the thickness of steel pipes by the plastic hardening and Bauschinger effect. In this study, a combined hardening model is proposed to effectively predict variations of yield strength in the circumferential direction of API-X65 and X70 steel pipes with relatively low t/D ratio during the forming process, which is expected to experience accumulated plastic strain of 2~3%, the typical Lüder band range in a low-carbon steel. Cyclic tensile tests of API-X65 and X70 steels were performed, and the parameters of the proposed model for the steels were calibrated using the test results. Bending-flattening tests to simulate repeated tension and compression during pipe forming were followed for API-X65 and X70 steels, and the results were compared with those by the proposed model and Zou et al. (2016), in order to verify the process of material model calibration based on tension-compression cyclic test, and the accuracy of the proposed model. Finally, parametric analysis for the yield strength of the steel plate in the circumferential direction of UOE pipe was conducted to investigate the effects of t/D and expansion ratios after O-forming on the yield strength. The results confirmed that the model by Zou et al. (2016) underestimated the yield strength of steel pipe with relatively low t/D ratio, and the parametric analysis showed that the t/D and expansion ratio have a significant impact on the strength of steel pipe.