• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.4 no.4
• /
• pp.42-49
• /
• 1995

It is not clearly known how defects or inclusions of a low carbon steel affect a fatigue strength. We study this issue using SM15C materials. The investigation is carried out by a quantitative evaluation, and experimental findings are: (1) a fatigue limit of A series smooth specimen is 205MPa, and that of B, C, D series is 245MPa, 304MPa and 245MPa, respectively. (2) the fatigue limit varies with respects to the stress distribution I the vicinity of a defects and crack. (3) the micro hole creates a half-circular shape crack, while the hole depth is not critical to the fatigue strength, (4) considering the fatigue strength, the hole diameter is more significant than the hole depth, and (5) Fatigue limit of artificially defected specimen is lower than that of a flawless one (5-10%), however, there exist allowance size and depth of defect which don't get to influence at fatigue limit.

• Korean Journal of Computational Design and Engineering
• /
• v.3 no.4
• /
• pp.236-242
• /
• 1998

This paper presents a development of computer aided cutting tool selection techniques for rough and finish turning operations. The developed system,. which is one of important activities for computer aided operation planning, firstly implements operation sequencing. Then, from relations of the size of machined area, recommended finishing allowance and maximum depth of cut, a main machining method is selected, a number of cut is calculated, cutting tools including toolholders and inserts are selected, and values for cutting parameters are determined. A cutting tool selection procedure is proposed for toolholders and inserts of ISO code in rough cutting, and some important parameters such as holder style, tool approach angle, tool function and its direction are described in detail. In order to demonstrate the validity of the system a case study is performed.

• Laser Solutions
• /
• v.12 no.3
• /
• pp.14-17
• /
• 2009

The laser welding was performed for the flange joint of two overlapped coaxial circular pipes which serve as the inlet and connector pipes of STS 316L. The laser welding test finally resulted in a good penetration depth of 1.8 to 2.0 mm. On the way to get the good welding quality, two important parameters were found to be optimized. One is the focal positioning which is the offset of the laser beam focus to the exact welding seam line, which is more critical in the inner flange laser welding. When the beam spot size was deviated more than $200\;{\mu}m$ from the seam line, welding of two pipes is failed. The other is a gap size since a certain amount of gap is inevitable due to fabrication tolerance, or artificial allowances for smooth insertion of a pipe. However, it is required to restrict the gap allowance within 0.2mm to avoid undesirable undercut on a welding bead.

• The Journal of Korean Academic Society of Nursing Education
• /
• v.26 no.4
• /
• pp.412-422
• /
• 2020

Purpose: This study is aimed at preparing basic data to increase professionalism in nursing and effective counter-strategies against future infectious diseases. For that purpose, this study investigated the experiences of nurses in a general hospital with an 800-bed size, temporarily closed after a confirmed case of COVID-19. Methods: This study was a qualitative study using individual in-depth interviews, and data were collected from 10 nurses in a university hospital temporarily closed from May 1 to June 13, 2020. Results: As a result of this study, the subjects were classified into 'COVID-19 and nursing', 'nursing work and vocation' and 'life changed with COVID-19'. Conclusion: In conclusion, there is a need for education that nurtures the ability of nurses to screen patients with infectious diseases well and to skillfully wear and remove protective clothing. In addition, in order to cultivate the expertise of nurses and respond efficiently to infectious diseases, a separate compensation, such as a risk allowance, is required along with the establishment of an infrastructure that fully supports personnel and supplies. A mental health program to relieve stress is also required.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.33 no.2
• /
• pp.187-199
• /
• 2009

Recently, the quality and design of the children's wear is being improved remarkably. Following the trend, the need for the research on the pattern making of children's wear is growing. At first, we tried to find out how the industry is doing the pattern making job through interview. Results are as follows. The target age ranges from 5 to 11 years old. For the sample size of pattern making, 7 years of age is preferred. It is not usual to develop the design pattern from the bodice block pattern. Instead, they use middle block pattern for each item, such as blouse, shirt, pants, skirt or jacket. Starting from these middle block pattern, they prepare individual designs. With the results, the aim of the research became to develop one of most frequently used middle block pattern. The blouse block pattern was selected for that purpose. To look into the existing patterns, we selected 4 methods, i.e. NM-method, T-method, O-method, E-methods. Theses patterns were compared through wearing test for the evaluation of comfort and fit using trial garments. The results indicated the NM-method was best among them. Specially waist line position, shoulder shape and size allowance was adequate. Alteration and adjustment of pattern draft was made onto the NM-method. Allowances for the bust circumference, across chest, across back and depth of arm was adjusted for better comfort as well as fine fit. Sidelines of the bodice and the underarm seam of the sleeves were curved for styling. After another wearing test, the final pattern was suggested as a blouse block pattern for 7 years old girl.