• Title/Summary/Keyword: Plate analysis

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Heat Transfer by Heat Generation in Electrochemical Reaction of PEMFC (고분자 전해질 연료전지에서 전기화학반응 열생성에 의한 열전달특성)

  • Han, Sang-Seok;Lee, Pil-Hyong;Lee, Jae-Young;Park, Chang-Soo;Hwang, Sang-Soon
    • Journal of the Korean Electrochemical Society
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    • v.11 no.4
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    • pp.273-283
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    • 2008
  • GDL(Gas Diffusion Layer) is one of the main components of PEM fuel cell. It transports reactants from the channel to the catalyst and removes reaction products from the catalyst to the channels in the flow filed plate. It is known that higher permeability of GDL can make it possible to enhance the gas transport through GDL, leading to better performance. And MEA's temperature is determined by gas and heat transport. In this paper, three dimensional numerical simulation of PEM fuel cell of parallel channel and serpentine channel by the permeability of GDL is presented to analysis heat and mass transfer characteristics using a FLUENT modified to include the electrochemical behavior. Results show that in the case of parallel channel, performance variation with change of permeability of GDL was not so much. This is thought because mass transfer is carried out by diffusion mechanism in parallel channel. Also, in the case of serpentine channel, higher GDL permeability resulted in better performance of PEM fuel cell because of convection flow though GDL. And mass transfer process is changed from convection to diffusion when the permeability becomes low.

A Study on Reliability Based Design Criteria for the Steel Highway Bridge (강도로교(鋼道路橋)의 신뢰성(信賴性) 설계규준(設計規準)에 관한 연구(硏究))

  • Cho, Hyo Nam;Kim, Woo Seok;Lee, Cheung Bin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.5 no.1
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    • pp.43-53
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    • 1985
  • This study proposes a reliability based design criteria for the steel bridge (H-beam, plate-girder and composite-beam), which is most common type of steel bridge, and also proposes the theoretical bases of nominal safety factors as well as load and rasistance factors based on the reliability theory. Major 2nd moment reliability analysis and design theories including both Cornell's MFOSM (Mean First Order 2nd Moment) Methods and Lind-Hasofer's AFOSM(Advanced First Order 2nd Moment) Methods are summarized and compared, and it has been found that Lind-Hasofer's approximate and an approximate Log-normal type reliability formula are well suited for the proposed reliability study. A target reliability index (β0=3.5β0=3.5) is selected as an optimal value considering our practice based on the calibration with the safety pravisions of the current steel bridge design code. Galambo's theory is used for the derivation of the algorithm for the evaluation of uncertainties associated with resistences by LRFD Format and SGST Format, whereas the magnitude of the uncertainties associated with load effects are chosen primarily by considering our level of practice. It may be concluded that the proposed LRFD reliability based design provisions for the steel highway bridge give more rational design than the current standard code for steel highway bridge.

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Extraction of Micro Filler from Bio-waste Material (Bio waste 소재로부터의 마이크로 필러 추출)

  • Nam, Gibeop;Song, Jung-Il
    • Composites Research
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    • v.31 no.5
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    • pp.209-214
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    • 2018
  • This paper explain about the development of environmental friendly, low cost and stable supply material i.e., rice husk and shell were used as micro incorporating bio waste filler. Those were processed by ball mill and analyzed through micro observation by FE-SEM, EDS and particle size distribution. The obtained filler was mixed with epoxy resin for the manufacturing of CFRP composite and study tensile properties. In EDS analysis main contents of rice husk and rice husk ash are C, O and Si. When rice husk was burned C and Si ration were increased. Shell powder has C, O and Ca. It caused CaCO3CaCO3 from shell. Surface weighted mean of rice husk powder is 6.19μm6.19μm and volume weighted mean is 14.77μm14.77μm. And it has rod type particles which caused hair and husk structure parts. Surface weighted mean of rice husk ash powder is 1.55μm1.55μm and volume weighted means is 8.20μm8.20μm. Surface weighted mean of shell powder is 2.53μm2.53μm and volume weighted mean is 5.79μm5.79μm. The tensile decreased with increasing the content of micro filler in CFRP composites. In case of rice husk, the significant decrement of tensile strength was observed. and in case of shell powder, there is no effect of changes take place in tensile strength.

Alternaria Leaf Spot Caused by Alternaria mali on Black Chokeberry in Korea (Alternaria mali에 의한 아로니아 점무늬낙엽병)

  • Hahm, Soo-Sang;Kwon, Mi-Kyung;Kim, Byung-Ryun;Han, Kwang-Seop;Nam, Yun-Gyu
    • Research in Plant Disease
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    • v.22 no.1
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    • pp.50-54
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    • 2016
  • In early June 2014, leaf spot symptoms were observed on black chokeberry (Aronia melanocarpa) in Yesan-gun and Geumsan-gun, Chungcheongnam-do in Korea. The initial symptoms on leave surfaces were brown small-circular spots with a yellow halo lesion, and gradually the small spots were fused, all of infected leaves dropped eventually. A fungus were isolated from the initial lesion, and cultured on potato dextrose agar. Colony color on upper surface of plate varied from olive gray to charcoal gray. Size of conidia mostly extend to 1950×59μm1950×59μm in nature and 2059×813μm2059×813μm in culture, with 3-8 transverse septa and usually no longitudinal septum or only 1 longitudinal septum in 1-3 of the transverse compartments, and also have a short or long beak. Pathogenicity was investigated using wounded or unwounded black chokeberry and apple leaves. After 7 days of inoculation, leaf spots were similar to the symptoms naturally occurred in the field. On the basis of mycological characteristics, pathogenicity, and ITS rDNA sequence analysis, this fungus was identified as Alternaria mali. This is the first report of Alternaria leaf spot on black chokeberry caused by A. mali in Korea.

An FSI Simulation of the Metal Panel Deflection in a Shock Tube Using Illinois Rocstar Simulation Suite (일리노이 록스타 해석환경을 활용한 충격파관 내 금속패널 변형의 유체·구조 연성 해석)

  • Shin, Jung Hun;Sa, Jeong Hwan;Kim, Han Gi;Cho, Keum Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.5
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    • pp.361-366
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    • 2017
  • As the recent development of computing architecture and application software technology, real world simulation, which is the ultimate destination of computer simulation, is emerging as a practical issue in several research sectors. In this paper, metal plate motion in a square shock tube for small time interval was calculated using a supercomputing-based fluid-structure-combustion multi-physics simulation tool called Illinois Rocstar, developed in a US national R amp; D program at the University of Illinois. Afterwards, the simulation results were compared with those from experiments. The coupled solvers for unsteady compressible fluid dynamics and for structural analysis were based on the finite volume structured grid system and the large deformation linear elastic model, respectively. In addition, a strong correlation between calculation and experiment was shown, probably because of the predictor-corrector time-integration scheme framework. In the future, additional validation studies and code improvements for higher accuracy will be conducted to obtain a reliable open-source software research tool.

Effect of the CO-OP Approach on Occupational Performance in ADHD : A Pilot Study (CO-OP 적용이 ADHD 아동의 작업수행에 미치는 효과 : 예비연구)

  • Shin, Min-Kyoung;Jo, Eun-Mi
    • Therapeutic Science for Rehabilitation
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    • v.4 no.2
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    • pp.51-62
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    • 2015
  • Objectives : This research was conducted to plan a strategy on the activities for ADHD who want to improve, and to use the strategy to find out how it influences the occupational performance when applying Cognitive Orientation to a daily Occupational Performance (CO-OP) approach. Methods : A single Subject AB design was employed. The subjects was one children with ADHD. The experiment consisted of 10 sessions spread over 7 weeks. The objective selected through COPM with guardians was improvement of chopstick use by children. In the course of the intervention, the overall CO-OP process was explained, continued analysis of performance and practice were encouraged in order to learn the skill of chopstick use, and guidance was given for DSS. Performance was measured by the time to move beans from one plate to another, starting from when the chopsticks were picked up. Results : The time to pick up the beans was 22.3s before the intervention, which was decreased by 7.2s to 15.1s after the intervention. The parents' COPM score showed an improvement of 3 points for performance and 4 points for satisfaction, demonstrating a clinically significant change. Conclusion : This study provides evidence that CO-OP is beneficial in occupation performance in children with ADHD.

Detection of Thermal Ratcheting Deformation for Cylindrical Shells by Ultrasonic Guided Wave (유도초음파를 이용한 원통형 쉘의 열 라체팅 변형 탐지)

  • Joo, Young-Sang;Lee, Hyeong-Yeon;Kim, Jong-Bum;Park, Chang-Gyu;Lee, Jae-Han
    • Journal of the Korean Society for Nondestructive Testing
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    • v.26 no.5
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    • pp.297-305
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    • 2006
  • The thermal ratcheting deformation at the reactor baffle and upper internal structure of the liquid metal reactor (LMR) can occur due to movement of the hot sodium free surface. In in-service inspection of reactor internals of LMR, a new inspection technique should be developed for the detection of the thermal ratcheting damage. In this study, an inspection technique using ultrasonic guided wave is proposed for the detection of the thermal ratcheting damage of cylindrical vessels. A 316L stainless steel cylindrical shell specimen has been prepared. The thermal ratchet structural tests were cyclically performed by heat-up up to 550C550C with steep temperature gradients along the axial direction after cool-down by cooling water. Ultrasonic guided wave propagation has been characterized by analysis of dispersion curve of the stainless steel plate. The zero-order antisymmetric A0A0 guided wave has been selected as the optimal mode for detection of the ratcheting deformation. It is confirmed that the thermal ratcheting deformation can be detected by the measurement of transit time difference of circumferentially propagated A0A0 guided waves.

Isolation and Characterization of Bacillus licheniformis SC082 Degrading Fibrin and Chitin from Shrimp Jeot-Gal (새우젓으로부터 혈전과 chitin 분해능을 지닌 균주 Bacillus licheniformis SC082의 분리 및 특성)

  • Cho, Eun-Kyung;Jung, Yu-Jung;Gal, Sang-Wan;Choi, Young-Ju
    • Journal of Life Science
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    • v.19 no.10
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    • pp.1424-1431
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    • 2009
  • Shrimp Jeot-Gal is a popular traditional Korean fermented seafood and has been used for seasoning. We isolated a bacterium showing strong extra-cellular fibrinolysis and chitinase activity from shrimp Jeot-Gal and the strain was designated SC082. SC082 was identified as Bacillus licheniformis by 16S rRNA sequence homology search. B. licheniformis SC082 exhibited optimum temperature, pH, and salt concentration at 37C37C, pH 7.0, and 6%, respectively. Substrate specificity of the culture supernatant from B. licheniformis SC082 was detected in fibrin, skim milk, and chitin plate. The fibrinolytic activity was highly maintained up to 50C50C at a pH of 7.0 for 3 hr and was stable up to pH 9.0 at 37C37C for 3 hr. The chitinase activity was remarkably induced by addition of 1.0% colloidal chitin and the pH and temperature optima of the enzyme were 5.0 and 45C45C, respectively. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis and zymogram analysis, this strain produced three fibrinolytic isozymes and two chitinase isozymes. The approximate molecular weights of the putative fibrinolytic enzymes were 23.0, 62.0, and 72.0 kDa and those of the chitinases were 62.0 and 55.0 kDa, respectively. The antioxidant activity of SC082 was also measured by using 2,2-diphenyl-l-picryl-hydrazyl (DPPH) free radical. The DPPH radical scavenging was slightly increased in a dose-dependent manner.

Effects of Feeding Fermented Colostrum Feed on the Growth to Piglets (발효초유사료 급여가 자돈의 성장에 미치는 영향)

  • Na, Seuk-Han;Choi, Seong-Hyun;Renchinthand, Gereltuya;Bae, Hyoung-Churl;Nam, Myoung-Soo
    • Food Science of Animal Resources
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    • v.28 no.3
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    • pp.355-362
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    • 2008
  • This study was carried out to assess the fermentation properties of lactic acid bacteria (LAB) isolated from bovine colostrum and effects of feeding fermented colostrum feed on the growth to piglet. A total of 427 colonies were isolated from bovine colostrum on the BCP plate count agar. These LAB isolated were subcultured in 10% reconstituted skim milk, and seven strain thereof were selected for their highest acid productions, and two strain thereof were finally selected for their excellent sugar utilization. These strains were identified as Streptococcus thermophilus and Streptococcus macedonicus based on l6S rDNA sequencing data, named S. thermophilus CNB-11 and S. macedonicus CNB-11 respectively. For fermentation profiles, sugar utilization, acid production and viable cell counts were excellent in S. thermophilus CNB-11 as compared with S. macedoniclts CNB-11 after 48 hour. The effect of feeding fermented colostrum feed 0.5% using S. thermophilus CNB-11 was investigated for growth rate, analysis of blood and incidence of diarrhea. 24 heads of piglets were divided into two groups: the experimental and the control of 12 animals each. The average growth rate in the pigs fed fermented colostrum feed was higher 16.73% compared with control diet (p<0.05). There were no differences in the concentrations of blood glucose, cholesterol, albumin and globulin in pigs fed fermented colostrum feed as compared with control piglets. Incidence of diarrhea was no in pigs fed fermented colostrum feed as compared with control piglets.

Study on CsRCI2D and CsRCI2H for improvement of abiotic stress tolerance in Camelina sativa L.

  • Lim, Hyun-Gyu;Kim, Hyun-Sung;Kim, Jung-Eun;Ahn, Sung-Ju
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.196-196
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    • 2017
  • Oilseed crop Camelina (Camelina sativa L.) is a suitable for biodiesel production that has high adaptability under low-nutrient condition like marginal land and requires low-input cost for cultivation. Enhanced abiotic stress tolerance of Camelina is very important for oil production under the wide range of different climate. CsRCI2s (Rare Cold Inducible 2) are related proteins in various abiotic stresses that predicted to localized at plasma membrane (PM) and endoplasmic reticulum (ER). These proteins are consist of eight-family that can be divided into tail (CsRCI2D/E/F/G) and no-tail (CsRCI2A/B/E/H) type of C-terminal. However, it is still less understood the function of C-terminal tail. In this study, CsRCI2D/H genes were cloned through gateway cloning system that used pCB302-3 as destination vector. And we used agrobacterium-mediated transformation system for generation of overexpression (OX) transformants. Overexpression of target gene was confirmed using RT-PCR and segregation ratio on selection media. We analyzed physiological response in media and soil under abiotic stresses using CsRCI2D and CsRCI2H overexpression plant. To compare abiotic stresses tolerance, wild type and CsRCI2D/H OX line seeds were sown on agar plate treated with various NaCl and mannitol concentration for 7 days. In the test of growth rate under abiotic stress on media, CsRCI2H OX line showed similar to NaCl and mannitol stress. In the other hand, CsRCI2D OX line showed to be improved stress tolerance that especially increased in 200mM NaCl but was similar on mannitol media. In greenhouse, WT and CsRCI2D/H OX lines for physiological analysis and productivity under abiotic stresses were treated 100, 150, 200mM NaCl. Then it was measured various parameters such as leaf width and length, plant height, total seed weight, flower number, seed number. CsRCI2H OX line in greenhouse did not show any changes in physiological parameters but CsRCI2D OX line was improved both physiological response and productivity under NaCl stress. Among physiological parameters of CsRCI2D OX line under NaCl stress, leaf length and width were observed shorter than WT but it were slightly longer than WT in 200mM NaCl stress. Furthermore, total seed weight of CsRCI2D OX line under stress displayed to decrease than WT in normal condition, but it was gradually raised with increasing NaCl stress then more than WT relatively. These results suggested CsRCI2D might be contribute to improve abiotic stress tolerance. However, function of CsRCI2H is need to more detail study. In conclusion, overexpression of CsRCI2s family can generate various environmental stress tolerance plant and may improve crop productivity for bio-energy production.

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