• Journal of ILASS-Korea
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• v.18 no.1
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• pp.9-15
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• 2013

Wall thinning of pipeline in power plants occurs mainly by flow acceleration corrosion (FAC), cavitation erosion (C/E), liquid droplet impingement erosion (LDIE). Wall thinning by FAC and C/E has been well investigated; however, LDIE in plant industries has rarely been studied due to the experimental difficulty of setting up a long injection of highly-pressurized air. In this study, we designed a long-term experimental system for LDIE and investigate the behavior of LDIE for three kinds of materials (A106B, SS400, A6061). The main control parameter was the air-water ratio (${\alpha}$), which was defined as the volumetric ratio of water to air (0.79, 1.00, 1.72). In order to clearly understand LDIE, the spraying velocity (${\nu}$) of liquid droplets was controled larger then 160 m/s and the experiments were performed for 15 days. Therefore, this research focuses relation between erosion rate and air-water ratio on the various pipe-flow materials. NPP(nuclear power plant)'s LDIE prediction theory and management technique were drawn from the obtained data.

• Journal of Yeungnam Medical Science
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• v.5 no.2
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• pp.25-30
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• 1988

Soft-tissue expansion is a new surgical technique of providing donor tissue in modern reconstructive surgery. This technique provides a quantity of tissue of similar color, texture, and hair-bearing qualities for reconstruction of adjacent defects. It is known that the expanded skin shows several constant histologic changes including the increase in collagen fibers and vascularity within dermis, and thinning of subcutaneous tissue and dermis. In this study, the author observed serial histologic changes of rabbit skin induced by progressive tissue expansion upto excessive expansion of 6 times. The results are as follows : 1. Changes in the thickness of the epidermis was minimal until 3 times of expansion, but slight thinning was observed at excessive expansion state. 2. The thickness of the dermis was progressively decreased, and collagen fibers in the dermis was rapidly increased in early phase of expansion. 3. The vascularity in the dermis was also progressively increased. 4. The skin appendages showed no structural changes even in excessive expansion. 5. The panniculus carnosus showed no atrophic changes and the thickness was maintained in excessive expansion.

• Journal of Korea Multimedia Society
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• v.22 no.12
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• pp.1356-1367
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• 2019

This paper proposes a novel active stereo matching technique using white auxiliary stripe pattern. The conventional active stereo matching techniques that uses two cameras and an active source such as projector can accurately estimate disparity information even in the areas with low texture compared to the passive ones. However, it is difficult that the conventional active stereo matching techniques using color code patterns acquire these patterns robustly if the object is composed of various colors or is exposed to complex lighting condition. To overcome this problem, the proposed method uses an additional white auxiliary stripe pattern to get and localize the color code patterns robustly. This paper proposes a process based on adaptive thresholding and thinning to obtain the auxiliary pattern accurately. Experimental results show that the proposed method more precisely measures the stepped sample whose depth is known in advance than the conventional method.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.7
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• pp.939-947
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• 1997

An experimental study of the skin friction measurement in a turbulent boundary-layer has been carried out. The skin friction measurements are made using the laser interferometer skin friction (LISF) meter, which optically detects the rate of thinning of an oil applied to the test surface. This technique produces reliable skin friction data over a wide range of flow situations up to 3-dimensional complicated flows with separation, where traditional skin friction measurement techniques are not applicable. The present measured data in a turbulent boundary-layer on a flat plate using the LISF technique shows a good comparison with the result from the previous velocity profile techniques, which proves the validity of the present technique. An extensive error analysis is carried out for the present technique yielding an uncertainty of about .+-.8%, which makes them suitable for CFD code validation purposes. Finally the measurements of the skin friction in a separated region after a surface-mounted obstacle are also presented.

• Structural Engineering and Mechanics
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• v.50 no.4
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• pp.563-573
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• 2014

In hydroforming, the general technique employed to overcome the problem of die corner filling consist in increasing the maximum fluid pressure during the forming process. This technique, in other hand, leads to other difficulties such as thinning and rupturing of the final work piece. In this paper, a new technique has been suggested in order to produce a part with complete filled corners. In this approach, two moveable bushes have been used. So, the workpiece moves driven by both bushes simultaneously. In the first stage, system pressure increases until a maximum of 15 MPa, providing aninitial tube bulge. The results showed that the pressure in this stage have to be limited to 17 MPa to avoid fracture. In a second stage, bushes are moved keeping the constant initial pressure. The punches act simultaneously at the die extremities. Results show that the friction between part and die decreases during the forming process significantly. Also, by using this technique it is possible to produce a part with reasonable uniform thickness distribution. Other outcomes of applying this method are the lower pressures required to manufacture a workpiece with complete filled corners with no wrinkling.

• The Korean Journal of Community Living Science
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• v.18 no.2
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• pp.247-263
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• 2007

This study was complied to analyze the professional agricultural techniques level and to suggest a desirable direction for the professional education system for women farmer. The research was conducted by using in-field surveys and interviews. Data was gathered by questionnaire from 147 women farmer in five specialized crop regions: strawberry, cucumber, rose, apple, and oyster mushroom. The results obtained are as follows. First, the technique levels in computer usage and electronic commerce, machinery usage, pesticide and fertilizer utilization, facility automation, and eco-agricultural cultivation were low. Second, the demand for professional education, evaluated through technique level by standard management diagnosis, was recognized. Areas of concern included: cucumber (temperature control, carbonic acid gas control, grading, funds management), strawberry (light control, soil temperature control, irrigation watering, shipping), rose (temperature control, light control, funds management, cooperated management), oyster mushroom (growth cabinet sterilizer), and apple (flower bud pinching, defloration, fruit thinning, funds management). Based on the results of this study, the following are suggestions for the planning of a professional education system for women farmer. First, it needs to address formal education in marketing, machinery usage, facilities automation, and techniques in pesticide and fertilizer utilization. Second, it needs to be a multi- level program with appropriate terminology at every level which is suitable to each age and ability of women farmer. Third, it needs a more comprehensive manual developed by need analysis of women farmer and a larger lecturer pool for professional education.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.4
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• pp.437-442
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• 2010

Flow-accelerated corrosion (FAC) leads to thinning of steel pipe walls that are exposed to flowing water or wet steam. From experience, it is seen that FAC damage to piping at fossil and nuclear plants can result in outages that require expensive repairs and can affect plant reliability and safety. CHECWORKS have been utilized in domestic nuclear plants as a predictive tool to assist FAC engineers in planning inspections and evaluating the inspection data so that piping failures caused by FAC can be prevented. However, CHECWORKS may be occasionally ignore local susceptible portions when predicting FAC damage in a group of pipelines after constructing a database for all the secondary side piping in nuclear plants. This paper describes the methodologies that can complement CHECWORKS and the verifications of CHECWORKS prediction results using numerical analysis. FAC susceptible locations determined using CHECWORKS for two pipeline groups of a nuclear plant was compared with determined using the numerical-analysis-based FLUENT.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.4
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• pp.323-329
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• 2013

This perform research of angle rated defect detection conditions and nuclear power plant piping defect detection by lock-In infrared thermography technique. Defects were processed according to change for wall-thinning length, Circumference orientation angle and wall-thinning depth. In the used equipment IR camera and two halogen lamps, whose full power capacitany is 1 kW, halogen lamps and target pipe's distance fixed 2 m. To analysis of the experimental results ensure for the temperature distribution data, by this data measure for defect length. Reliability of lock-In infrared thermography data is higher than Infrared thermography data. This through research, Shape of angle rated defect is identified industry place. It help various angles defect detection in the nuclear power plant in operation.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.1
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• pp.34-39
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• 2013

In the advanced research deducted infrared thermography (IRT) test using 4 inch pipe with artificial wall-thinning defect to measure on the wall-thinned nuclear pipe components. This study conducted for defect detection condition of nuclear small-bore pipe research using deducted condition in the advanced research. Defect process is processed by change for defect length, circumferential direction angle, wall-thinning depth. In the used equipment IR camera and two halogen lamps, whose full power capacitany is 1 kW, halogen lamps and Target pipe experiment performed to the distance of the changed 1 m, 1.5 m, 2 m. To analysis of the experimental results ensure for the temperature distribution data, by this data measure for defect length. artificial defect of 4 inch pipe is high reliability in the 2 m, but small-bore pipe is in the 1.5 m from the defect clearly was detected.

• International Journal of Quality Innovation
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• v.6 no.3
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• pp.204-215
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• 2005

This paper explores innovative manufacturing processes, which can be used to manufacture the national musical instrument of Trinidad and Tobago, the Musical Steel Drum or Steel Pan. The main manufacturing process used today is the manual hand-forming technique. In order to achieve more consistent and deeper formed components while maintaining the high quality of the instrument, it is proposed that the Marforming process and the Flow-forming process, an adaptation of the Spinforming process, be used more frequently in the future to replace the traditional Hand-forming method. In the traditional Spinforming technique material is pushed from the outer circumference of the metal disc to the center in progressive passes of the former. This results in a thinning of the outer region of the formed component with thickening of the center, however the opposite is required for the musical steel drum and by adapting the process the required strain distributions were achieved. Evaluation took the form of strain analyses of pre-formed steel drums and visual inspection of the quality of the surface finish. It was found that the Marformed components had the smallest range of strain values while the Spinformed components had the largest range.