• Title/Summary/Keyword: Engineering interdisciplinary design

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Failure Analysis of SCM435 Bolt for Fixing Automotive Air Brake Spring (자동차 에어 브레이크 스프링 고정용 SCM435 볼트의 파손 해석)

  • Yun, Seo-Hyun;Kim, Min-Heon;Nam, Ki-Woo
    • Journal of the Korean Society of Industry Convergence
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    • v.23 no.1
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    • pp.73-81
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    • 2020
  • This study analyzed the causes of failure of SCM435 bolts that fix the springs of automobile air brakes that have been fractured during use. The cause of failure was analyzed using SEM, EDS, metallogical microscope and Vickers hardness tester. In the fracture, the ratchet mark began at the outer boundary of crack origin, and the grains at crack origin were found to have clear intergranular corrosion. One SCM435 bolt was subjected to a stress of 398 MPa, it's a stress of about 80% of the fatigue limit. As a result of such a large applied stress, cracks occurred at the corrosion origin and were fractured. In order to prevent the SCM435 bolt from fracture, it is necessary to use the correct composition, the accuracy of heat treatment, preventing damage by external impact, preventing corrosion of the damage part by moisture, and introduction a compressive residual stress by peening.

Degradation characteristics and intermediate study of tetracycline in aqueous system by liquid ferrate(VI) (Liquid ferrate(VI)에 의한 다양한 수중 환경에서의 tetracycline 분해특성 및 중간생성물 연구)

  • Park, Kyeong-Deok;Kang, Dong-Hwan;So, Yoon-Hwan;Cho, Joung-Hyung;Kim, Il-Kyu
    • Journal of Korean Society of Water and Wastewater
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    • v.34 no.1
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    • pp.61-73
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    • 2020
  • Tetracycline is one of the most commonly used antibiotics in domestic and foreign livestock industries to suppress the growth of pathogens. Tetracycline has been reported as a non-biodegradable compound. Therefore it has been not completely removed in the sewage treatment process. In this study, tetracycline was degraded using liquid ferrate (VI). Based on these experiments, the optimal water condition (pH and water temperature) were selected, appropriate liquid ferrate (VI) dosage was calculated, and finally the degradation pathway was estimated with the intermediate products detected by LC/MS/MS. All degradation experiments were completed within 30 seconds and the optimal condition was obtained in basic condition (pH 10) at room temperature (20℃). And the appropriate molar ratio between tetracycline and liquid ferrate (VI) was 12.5:1. Finally, 12 intermediate products were detected with LC/MS/MS and the degradation pathways and the degradation pathways and proposed the degradation pathways.

Modeling and Simulation of the Cardiovascular System Using Baroreflex Control Model of the Heart Activity (심활성도 압반사 제어 모델을 이용한 심혈관시스템 모델링 및 시뮬레이션)

  • Choi Byeong Cheol;Jeong Do Un;Shon Jung Man;Yae Su Yung;Kim Ho Jong;Lee Hyun Cheol;Kim Yun Jin;Jung Dong keun;Yi Sang Hun;Jeon Gye Rok
    • Journal of Biomedical Engineering Research
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    • v.25 no.6
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    • pp.565-573
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    • 2004
  • In this paper, we proposed a heart activity control model for simulation of the aortic sinus baroreceptor, which was the most representative baroreceptor sensing the variance of pressure in the cardiovascular system. And then, the heart activity control model composed electric circuit model of the cardiovascular system with baroreflex control and time delay sub-model to observe the effect of time delay in heart period and stroke volume under the regulation of baroreflex in the aortic sinus. The mechanism of time delay in the heart activity baroreflex control model is as follows. A control function is conduct sensing pressure information in the aortic sinus baroreceptor to transmit the efferent nerve through central nervous system. As simulation results of the proposed model, we observed three patterns of the cardiovascular system variability by the time delay. First of all, if the time delay over 2.5 second, aortic pressure and stroke volume and heart rate was observed non-periodically and irregularly. However, if the time delay from 0.1 second to 0.25 second, the regular oscillation was observed. And then, if time delay under 0.1 second, then heart rate and aortic pressure-heart rate trajectory were maintained in stable state.

An Education Model of a Nano-Positioning System for Mechanical Engineers

  • Lee Dong-Yeon;Gweon Dae-Gab
    • Journal of Mechanical Science and Technology
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    • v.20 no.10
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    • pp.1702-1715
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    • 2006
  • The increasing use of nano-positioners in a wide variety of laboratory and industrial applications has created a need for nano-mechatronics education in all engineering disciplines. The subject of nano-mechatronics is broad and interdisciplinary. This article focuses on the way nano-mechatronics is taught in department of mechanical engineering at Korea Advanced Institute of Science and Technology (KAIST). As one model of nano-positioning systems, design and experimental methodology is presented in this article. For design phase, the stiffness and resonant frequencies are found analytically and verified by using a commercial finite element analysis program. Next, for experimental phase, various tests are performed to access the performances of the designed nano-positioner, for example, sine-tracking, multi-step response and travel-range check etc. Finally, the definition of 'separation frequency' is described and some comments are discussed.

Design Criteria of a Future Container Crane for Megaships (초대형 선박용 차세대 컨테이너 크레인의 설계기준)

  • LEE SUK-JAE;HONG KEUM-Shik
    • Journal of Ocean Engineering and Technology
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    • v.18 no.6 s.61
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    • pp.101-107
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    • 2004
  • In this paper, the design criteria of future container crane for megaships are investigated. The current loading/unloading capacity of a typical container crane, roughly 30 moves/hr, is too law to meet the requirements of future super containerships, which are expected over 15,000 TEU. After examining the transition of containerships through the years and studying the research trend in developed countries, the specifications of the container crane that can Meet a 15,000 TEU containership are proposed. The structure, trolley and hoist mechanism, outreach, backreach, capacity, speeds, durability, and stability of the future container crane are described.

Finite Element Analysis for the Optimal Shape of the High Voltage Insulator for Power Transmission Lines (송전선로용 고전압 절연체의 최적 형상에 대한 유한요소 해석)

  • Kim, Taeyong;Sanyal, Simpy;Rabelo, Matheus;Yi, Junsin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.1
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    • pp.66-71
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    • 2022
  • The insulator used for the transmission line is a device that is bonded with a cap, pin, ceramic, and cement to withstand insulation capacity and mechanical load. The insulator design can help to reduce the dispersion of the electric field; thus, the optimization of today's design, especially as demanded power grows, is critical. The designs of four manufacturers were used to perform a comparative analysis. Under dry circumstances of the new product, an electric field distribution study was done with no pollutants attached. Manufacturer D's design has the best voltage uniformity of 24.33% and the arc length of 500 mm or more. Manufacturer C's design has an equalizing voltage of more than 2% higher than that of other manufacturers. The importance of the design of the insulator and the number of connections according to the installation conditions is very efficient for transmission lines that will increase in the future.

A study on Weibull Probability Statistics Characteristics for Vickers Hardness of Degraded Stainless Steel (열화된 스테인리스강의 비커스 경도에 대한 와이블 확률 통계 특성에 관한 연구)

  • Nam, Ki-Woo;Cho, Sung-Duck;Kim, Seon-Jin;Ahn, Seok-Hwan
    • Journal of Power System Engineering
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    • v.21 no.5
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    • pp.79-85
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    • 2017
  • Vickers hardness is an important material in the design and reliability is required. Therefore, these values are very important as the basic data for design, manufacture and development, and the identification of quantitative probability distribution characteristics such as mean and dispersion is a very important parameter in design. In this study, Vickers hardness was measured after artificially heat-treated in the temperature range 753K, where chrome depletion near the grain boundary occurred for three kinds of stainless steels, and the Vickers hardness were evaluated. From the results, Vickers hardness increased with increasing heat treatment temperature. In Weibull distribution for Vickers hardness, the dispersion of STS310S at 813K and 873K was small, and the dispersion of STS316L at 753K, 933K and 993K was small. Also, STS347H exhibited the lowest dispersion at 753K in three kinds of stainless steels. The scale parameter increased with increasing heat treatment temperature in three kinds of stainless steels.

Design and Implementation of large Beacon Monitoring System (대형등명기 모니터링 시스템 설계 및 구현)

  • Kim, Ji-Hoon;Ye, Seong-Hyeon;Han, Soonhee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.18 no.10
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    • pp.2516-2522
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    • 2014
  • Our country has a convoluted coastline and the marine weather fluctuates locally, so it needs effective AtoN operation for the safe navigation of vessels and fishing boats sailing the coast. Especially, large beacon must ensure the safety of the vessels and always lit at night. If large beacons installed in the lighthouse are not lit, vessels can not assure their location. Thus the accidents is likely to occur, which can cause great economic damage. In this paper, we developed a monitoring system of large beacon to monitor and control the status of information. This system was designed for a special purpose of taking precautions against possible accidents on the sea.

A Study on Convergence Education of IT & Design for Training Creative Talent (창의적 인재 양성을 위한 IT & 디자인 분야의 융합 교육 연구)

  • Kwon, Hyo-Jeong
    • Journal of Korea Multimedia Society
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    • v.17 no.11
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    • pp.1354-1362
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    • 2014
  • In order to solve the complicated problems faced by the spread of diversified information devices and changes in the user environment in recent years, the importance of training creative talent as well as the need for interdisciplinary convergent approach have emerged. As a future technology development project, convergence education with the design sector for training creative talent in the IT field is also urgent. In this study, we recognized the importance and problems of the convergent approach between IT and design sector by examining the convergence theory and cases with a focus on effective creativity development and sought a new direction for convergence education in the future by investigating the awareness on the convergent approach of college students and analyzing the results. This will be able to have significance as a basic study for discovering creative and innovative convergent talent in the IT and design sector in the future and strengthening basic competence.

Enhanced In Vitro Protein Synthesis Through Optimal Design of PCR Primers

  • Ahn Jin-Ho;Son Jeong-Mi;Hwang Mi-Yeon;Kim Tae-Wan;Park Chang-Kil;Choi Cha-Yong;Kim Dong-Myung
    • Journal of Microbiology and Biotechnology
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    • v.16 no.3
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    • pp.355-359
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    • 2006
  • The functional stability of mRNA is one of the crucial factors affecting the efficiency of in vitro translation. As the rapid degradation of mRNA in the cell extract (S30 extract) causes early termination of the translational reactions, extending the mRNA half-life will improve the productivity of the in vitro protein synthesis. Thus, a simple PCR-based method is introduced to increase the stability of mRNA in an S30 extract. The target genes are PCR-amplified with primers designed to make the ends of the transcribed mRNA molecule anneal to each other. When compared with normal mRNA, the mRNA with the annealing sequences resulted in an approximately 2-fold increase of protein synthesis in an in vitro translation reaction. In addition, sequential transcription and translation reactions in a single tube enabled direct protein expression from the PCR-amplified genes without any separate purification of the mRNA.