• Journal of Ocean Engineering and Technology
• /
• v.2 no.2
• /
• pp.78-86
• /
• 1988

In order to investigate the corrosion pit occurrence and growth characteristic of M.E.F.(martensite encapsulated islands of ferrite) dual phase steel was made with a suitable heat treatment of raw material(SS41), a corrosion fatigue test was performed under rotary bending in the salt solution having a concentration from 0.01 wt percent to 3.5 wt percent. The fatigue strength of dual phase steel was remarkably decreased with an increase in concentration of salt solution; approximately from 63% to 80% in case of dual phase steel and from 40% to 71% in case of raw material. Corrosion pit occurred in the martensite phase and fatigue cracks from corrosion pits were selectively propagated in martensite phases. In the observation of corrosion pits at the origin of fatigue cracks, it had been found that corrosion pits were grown into hemispherical pits and a/c(the surface diameter, 2c and the depth, a of corrosion pit)was about 1.0-1.5regardless of the variation of salt solution concentration. The difference of corrosion pit depth growth rate was increased with an increase in concentration of salt solution according to an increase in stress level.

• Journal of Digital Convergence
• /
• v.19 no.2
• /
• pp.501-508
• /
• 2021

The purpose of this study is to qualitatively analyze the perceptions of aesthetic values of working women taking ballet fitness classes and to find ways to properly establish ballet fitness classes according to the opinions of the study participants. Participants in the study were 9 working women taking ballet fitness classes at local educational institutions, and FGI (Focus Group Interview) was conducted, and the interview was conducted based on a semi-structured questionnaire. Subsequently, the categorization content was derived through expert review and peer review. As a result, first, the study participants expressed their dissatisfaction, hoping that the ballet fitness class helped improve their daily enjoyment and pain, and even watched ballet performance with interest. Second, the participants of the study were actively publicizing the benefits of ballet fitness classes to their families and nearby acquaintances, and hoped that this exercise would help improve the difficult image of ballet. Based on this study, ballet fitness classes were expected to be sufficiently established as a hobby exercise for working women.

• Journal of Animal Environmental Science
• /
• v.17 no.3
• /
• pp.155-162
• /
• 2011

This study was conducted to suggest the measurement procedure and to build up national greenhouse gas inventory database of animal agricultural sector by assessing methane and nitrous oxide emissions according to IPCC guidelines for national greenhouse gas inventory report in order to correspond to the Climate Change Convention. Ten house-made steady-state Half dome floating chambers were used to collect air samples emitted from slurry stored in the pit under the slat. Those chambers were spread out in order that air samples might represent the whole area of slurry under the slat. Fresh air was pumped into the chambers by $5{\sim}9{\ell}/min$ and air inside the chambers was sampled by $1{\ell}/min$. Surplus air by the higher flow rate of fresh air than sampling flow rate was passed through a hole on the top of chambers. Nitrous oxide fluxes measured from 10 locations would be negligible as concentrations between background air and sampled air from the chambers were within the error range. However, mean $CH_4$ fluxes were $0.15{\sim}1.02mg/m^2{\cdot}s$. The application of continuous greenhouse gas measurement techniques would be preferred if the patterns of greenhouse gas emissions are considered.