• Title/Summary/Keyword: Technical effect

Search Result 2,790, Processing Time 0.04 seconds

Effect of Dynamic Flow on the Structure of Inhibition Layer in Hot-dip Galvanizing

  • Jin, Young Sool;Kim, Myung Soo;Kim, Su Young;Paik, Doo Jin
    • Corrosion Science and Technology
    • /
    • v.10 no.1
    • /
    • pp.30-36
    • /
    • 2011
  • The effect of dynamic flow or forced convection were investigated and compared on the formation of inhibition layer, galvanizing and galvannealing reactions through the hot-dip galvanizing simulator with the oscillation of specimen in zinc bath, continuous galvanizing pilot plant with zinc pumping system through the snout and continuous galvanizing operation with Dynamic $Galvanizing^{TR}$ system. The interfacial Al pick-up was not consistent between the results of simulator, pilot plant and line operation, but the morphology of inhibition layer became compact and refined by the forced convection. The growth of Fe-Zn intermetallics at the interface was inhibited by the forced convection, whereas the galvannealing rate would be a little promoted.

Advances in the understanding of molybdenum effect on iodine and caesium reactivity in condensed phase in the primary circuit in nuclear severe accident conditions

  • Gouello, Melany;Hokkinen, Jouni;Karkela, Teemu
    • Nuclear Engineering and Technology
    • /
    • v.52 no.8
    • /
    • pp.1638-1649
    • /
    • 2020
  • In the case of a severe accident in a Light Water Reactor, the issue of late release of fission products, from the primary circuit surfaces is of particular concern due to the direct impact on the source term. CsI is the main iodine compound present in the primary circuit and can be deposited as particles or condensed species. Its chemistry can be affected by the presence of molybdenum, and can lead to the formation of gaseous iodine. The present work studied chemical reactions on the surfaces involving gaseous iodine release. CsI and MoO3 were used to highlight the effects of carrier gas composition and oxygen partial pressure on the reactions. The results revealed a noticeable effect of the presence of molybdenum on the formation of gaseous iodine, mainly identified as molecular iodine. In addition, the oxygen partial pressure prevailing in the studied conditions was an influential parameter in the reaction.

Effect of Laser Welding Variables on the Formability of Si Added Steel Welds (3wt% Si 첨가강의 레이저용접부 성형성에 미치는 용접변수의 영향)

  • Park, Joon-Sik;Woo, In-Su;Lee, Jong-Bong
    • Journal of Welding and Joining
    • /
    • v.24 no.4
    • /
    • pp.15-21
    • /
    • 2006
  • The aim of present study is to investigate the effect of welding parameters and heat treatment conditions on the formability of the $CO_2$ laser welded silicon steel sheet. It was found that there is optimum range of the heat input ($0.6{\sim}0.7kJ/cm$) and gap distance ($0.125{\sim}0.150mm$) for the high tensile strength and the avoidance of the fracture in weld metal. Also, it was essential fur the improvement of formability to perform pre- and post-welding heat treatment which cause the uniform mixture of base metal and welding consumable.

The Effects of TiN Particles on the HAZ Microstructure and Toughness in High Nitrogen TiN Steel

  • Jeong, H.C.;An, Y.H.;Choo, W.Y.
    • International Journal of Korean Welding Society
    • /
    • v.2 no.1
    • /
    • pp.25-28
    • /
    • 2002
  • In the coarse grain HAZ adjacent to the fusion line, most of the TiN particles in conventional Ti added steel are dissolved and austenite grain growth is easily occurred during welding process. To avoid this difficulty, thermal stability of TiN particle is improved by increasing the nitrogen content in steel. In this study, the effect of hlgh nitrogen TiN particle on preventing austenite grain growth in HAZ was investigated. Increased thermal stability of TiN particle is helpful for preventing the austenite grain growth by pinning effect. High nitrogen TiN particle in simulated HAZ were not dissolved even at high temperature such as 1400'E and prevented the austenite grain growth in simulated HAZ. Owing to small austenite grain size in HAZ the width of coarse grain HAZ in high nitrogen TiN steel was decreased to 1/10 of conventional TiN steel. Even high heat input welding, the microstructure of coarse grain HAZ consisted of fine polygonal ferrite and pearlite and toughness of coarse grain HAZ was significantly improved.

  • PDF

The Effects of Enjoyment Factors on Recreation Specialization of Water Sports Participants (해양스포츠 참여자의 즐거움 요인이 레크리에이션 전문화에 미치는 영향)

  • NAM, Sang-Back;KWON, Il-Kwon
    • Journal of Fisheries and Marine Sciences Education
    • /
    • v.28 no.2
    • /
    • pp.356-365
    • /
    • 2016
  • The purpose of this study was to verify the influences of sport enjoyment factors on recreation specialization of water sports participants. The study conducted a research survey through purposive sampling method after selecting 4 water sports center in Busan. 260 questionnaires distributed and 246 were selected as final valid sample by removing 14 questionnaires that have insufficient answers. Then data were analyzed through exploratory factor analysis, reliability analysis, correlation analysis, and multiple regression analysis using SPSS Window ver. 20.0. The results were as followings. First, the enjoyment factors have a positive effect on recreation specialization. Second, escaping from daily routine and improving technical skill dimensions of enjoyment factors have an influence on centrality of life. Third, improving technical skill dimension of enjoyment factors have a positive effect on past experience. Lastly, flow and improving technical skill dimensions of enjoyment factors have an influence on economic investment.

A reliable approach for determining concrete strength in structures by using cores

  • Durmus, Aysegul;Ozturk, Hasan Tahsin;Durmus, Ahmet
    • Computers and Concrete
    • /
    • v.11 no.5
    • /
    • pp.463-473
    • /
    • 2013
  • As known, concrete classes are described as strength of standard specimens produced and kept in ideal conditions, not including reinforcement and not subjected to any load effect before. Under the circumstances, transforming core strengths to the standard specimen strength is necessary and considering all parameters, affected on the core strength, is inevitable. In fact, effects of the reinforcement and the load history on concrete strength are generally neglected when these mentioned transforms are performing. The main purpose of this paper is investigating the effects of the reinforcement and the load history on the core strength. This investigation is experimentally performed on cores drilled from specimens having different keeping conditions, reinforced, unreinforced, subjected to bending and central pressure in various proportions of failure load during specified periods. Obtained results show that the importance of these effects cannot be neglected.

Special cases in fatigue analysis of wind turbines

  • Gunes, Onur;Altunsu, Elif;Sari, Ali
    • Wind and Structures
    • /
    • v.32 no.5
    • /
    • pp.501-508
    • /
    • 2021
  • The turbine industry demands a reliable design with affordable cost. As technological advances begin to support turbines of huge sizes, and the increasing importance of wind turbines from day to day make design safety conditions more important. Wind turbines are exposed to environmental conditions that can affect their installation, durability, and operation. International Electrotechnical Commission (IEC) 61400-1 design load cases consist of analyses involving wind turbine operating conditions. This design load cases (DLC) is important for determining fatigue loads (i.e., forces and moments) that occur as a result of expected conditions throughout the life of the machine. With the help of FAST (Fatigue, Aerodynamics, Structures, and Turbulence), an open source software, the NREL 5MW land base wind turbine model was used. IEC 61400-1 wind turbine design standard procedures assessed turbine behavior and fatigue damage to the tower base of dynamic loads in different design conditions. Real characteristic wind speed distribution and multi-directional effect specific to the site were taken into consideration. The effect of these conditions on the economic service life of the turbine has been studied.