• Journal of Welding and Joining
• /
• v.33 no.1
• /
• pp.24-29
• /
• 2015

Residual stresses arising from the materials processing such as welding and joining affect significantly the structural integrity depending on the external loading condition. The quantitative measurement of the residual stresses is of great importance in order to characterize the effects of the residual stresses on the structural safety. In this paper, we introduce a newly devised destructive technique, the contour method (CM), which is applied for the measurements of the residual stress distributions through the thickness of a 80 mm thick steel weld. Residual stresses are evaluated from the contour, which is the normal displacement on a cut surface produced by the relaxation of residual stresses, using a finite element model. The CM provides a two-dimensional map of the residual stresses normal to the cut surface. The CM developed in the present study was validated in comparison with the residual stress distribution determined by a well-established neutron-diffraction residual stress instrument (RSI) instrumented in HANARO neutron research reactor.

• KIEE International Transactions on Power Engineering
• /
• v.2A no.3
• /
• pp.121-128
• /
• 2002

This study proposes a new method for transmission system expansion planning using fuzzy integer programming. It presents stepwise cost characteristics analysis which is a practical condition of an actual system. A branch and bound method which includes the network flow method and the maximum flow - minimum cut set theorem has been used in order to carry out the stepwise cost characteristics analysis. Uncertainties of the permissibility of the construction cost and the lenient reserve rate and load forecasting of expansion planning have been included and also processed using the fuzzy set theory in this study. In order to carry out the latter analysis, the solving procedure is illustrated in detail by the branch and bound method which includes the network flow method and maximum flow-minimum cut set theorem. Finally, case studies on the 21- bus test system show that the algorithm proposed is efficiently applicable to the practical expansion planning of transmission systems in the future.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.18 no.3 s.39
• /
• pp.39-56
• /
• 1990

The purpose of this study is to analyze the roadside slope of mountainous Parkway. 48 sites were selected by Random Ranking Sampling. This study was researched on the slope condition with the cause of occurrence, the situation of fundamental engineering works and vegetation on slopes. The main results of this research are summarized as follow ; 1. Slope shapes are shown nine types in cut slope and four types in fill slope. 2. Generally, fill slopes are larger than cut slopes in slop area. 3. Grade is more steep than standard grade. 4. Main engineering works, which constructed for slope stability, are terracing, side-ditch wall, channel, concrete trellis works and wire fence. 5. Roundabout channel were many constructed within the sector of Ukmojeong-Deokdong, but were few constructed within the sector of Banseon-Seongsam pass and Cheoneun Temple-Seongsam pass. 6. Most. of side-ditch wall were constructed of concrete and wet-masonry. 7. In vegetation works, many exterior species were selected. 8. Planting pattern was not combinated with the national park landscape.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.6
• /
• pp.81-88
• /
• 2022

Titanium alloy (Ti-6Al-4V) has excellent mechanical properties and high specific strength; therefore, it is widely used in aerospace, automobile, defense, engine parts, and bio fields. Particularly in the aerospace field, as it has a low specific gravity and rigidity, it is used for the purpose of increasing energy efficiency through weight reduction of parts, and most have a thin-walled structure. However, it is extremely difficult to machine thin-walled shapes owing to vibration and deformation. In the case of thin-walled structures, the cutting forces and vibrations rapidly increase depending on the cutting conditions, significantly affecting the surface integrity and tool life. In this study, machining experiments on thin-wall milling of a titanium alloy (Ti-6Al-4V) were conducted for each experimental condition with different axial depths of cut, radial depth of cut, and machining sequence. The machining characteristics were analyzed, and an effective machining method was derived by a comprehensive analysis of the machined surface conditions and cutting signals.

• IE interfaces
• /
• v.9 no.1
• /
• pp.13-24
• /
• 1996

Quality of injection molded parts is dependent on both mold design and processing conditions. From the mold design point of view, an optimal shrinkage should be used to compensate the shrinkage of molded parts. From the processing point of view, it is important to analyze the priority of processing conditions because a number processing conditions affect the quality of molded parts. Processing analysis employing the design of experiment was performed, and the shrinkage of molded part was considered as a characteristic parameter to improve the quality. As the result of the analysis of variance on SN ratio of a characteristic value, injection speed and bolding pressure were selected as two effective process parameters. Regression analysis on shrinkage and processing conditions was carried out, and an optimal processing condition was obtained by the response surface analysis. Shrinkage at the optimal condition could be used to reduce the number of try-cut at the step of mold making. The ranges of indirect control parameter, such as maximum cavity pressure or weight, measured at the optimal processing condition were used for monitoring the quality of molded parts in process.

• Current Research on Agriculture and Life Sciences
• /
• v.31 no.1
• /
• pp.56-60
• /
• 2013

This research was carried out to produce rainbow-colored roses from white cut rose, Rosa hybrida 'Denice', to meet customers' desire of having various colors of roses. The higher temperature of dyeing solution used, the faster coloring time surveyed. In high temperature, the flowering speed of cut flower accelerated and after treating more than 4 hours, the edges of flowers became too dark or dry. In the condition of concentration of dyeing solution, $11g{\cdot}L^{-1}$ dyed faster than $7.5g{\cdot}L^{-1}$, however, no differences between $15g{\cdot}L^{-1}$ and $11g{\cdot}L^{-1}$ have observed. It looked fast coloration at the stage of early blooming, but all three different petal opening stages need similar time to get even coloration from outer to inner petals. For the consideration of commercial value, flowers with 3-4 petals opened are better quality than flowers with less petals opened. It was possible to make rainbow-colored rose by dipping 'Denice' with 3 primary color combination, Hot Pink, True Blue, and Yellow dyes, at the best result conditions of $20^{\circ}C$ solution temperature, 3-4 petals opening stage, 11g/L concentration of dye solution and 3 hours dipping, respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.6 no.4
• /
• pp.130-137
• /
• 1997

The demand for wire-cut EDM is increasing rapidly in the die and tool making industry. In this study machining characteristics such as machining rate, surface roughness, hand drum form and hardness of machined material are investigated experimentally under the conditions varing pulse on time, pulse off time, peak voltage, wire tension after fixing other conditions in SKD 11 and brass and brass workpiece. It was found that various operating conditions had significant influences on machining characteristics. But the hardness of workpiece was uneffected by operating conditions. Also it was obtained experimentally that brass workpeice had better machinability than SKD 11 one.dition according to the current(Ip) in an electric spark machine : 1) Electrode is utilized Cu and Graphite. 2) Work piece is used the material of carbon steel. The condition of experiment is : 1) Current is varied 0.7(A) to 50(A) and the time of electric discharging to work piece in each time is 30(min) to 60(min). 2) After the upper side of work piece was measured in radius(5$\mu$m) of stylus analyzed the surface roughness to ade the table and graph of Rmax by yielding data. 3) Electro wear ratio is : \circled1Cooper was measured ex-machining and post-machining by the electronic balance. \circled2The ex-machining of graphite measured by it, the post-machining was found the data from volume $\times$specific gravity and analyzed to made its table and graph on ground the data. 4) In order to keep the accuracy of voltage affected to the work piece was equipped with the A.V. R and the memory scope was sticked to the electric spark machine. 5) In order to preserve the precision of current, to get rid of the noise occured by internal resistance of electric spark machine and to force injecting for the discharge fluid , it made the fixed table for a work piece to minimize the work error by means of one's failure during the electric discharging.

• The Journal of the Convergence on Culture Technology
• /
• v.8 no.6
• /
• pp.765-773
• /
• 2022

This study is a study on the application of a horizontal excavation machine system to improve constructability. In this study, the structural stability of non-covered temporary facilities was evaluated by comparing field measurements and numerical analysis. In addition, the appropriateness of the measurement results was analyzed by comparing and analyzing the results of numerical analysis with the analysis results applying the Gaussian probability density function to the measurement results. In this study, structural safety and long-term durability of the linkage were analyzed based on numerical analysis. As a result of the study, it was analyzed that the non-open cut method (H.A.S. method) of this study secures structural safety and constructability as the behavior in the actual construction process is more safe than the numerical analysis results, even if the uncertainty of the ground condition is taken into account.

• Journal of Bio-Environment Control
• /
• v.22 no.2
• /
• pp.175-181
• /
• 2013

These studies were identified the effect of four types of non-perforated breathable (NPB) packing film and three sizes on storage ability of fresh-cut for ready to eat packaging at $5^{\circ}C$ for 25 days and $10^{\circ}C$ for 15 days storage in Salicornia herbacea. The fresh weight loss was less than 2% in every films at $5^{\circ}C$ condition after 25 days storage, and the $10^{\circ}C$ also had same result on 15 days storage except 100,000 cc NPB film. Compare with storage after 15 days, storage condition at $5^{\circ}C$ had shown better result under the 1% fresh weight loss rate. The 5,000 cc and $5^{\circ}C$ condition had been shown the characteristics of MA packaging in carbon dioxide and oxygen concentrations. The ethylene concentration in vacuum film was higher 10 to 100 times than in NPB film treatments during storage. But ethylene concentration was not statistically significant differences among size treatments. Every conditions had been measured the anti-oxidant activity by DPPH method after storage at $5^{\circ}C$ for 25 days and $10^{\circ}C$ for 15 days. S. herbacea at $5^{\circ}C$ had been more than twice of activity compare with that at $10^{\circ}C$. 100,000 cc NPB film had been higher contents of anti-oxidant activity at $5^{\circ}C$ and $10^{\circ}C$. As the fresh-cut sizes, 3 cm and 5 cm sizes had changed depending on film types but 10 cm were not effected by the film types in the DPPH activity. When panel test had been tried to measure the visual quality and off-flavor after storage, $5^{\circ}C$ with a filme of 5,000 cc treatment had established higher value than other treated conditions. As these results, it's may be suggested that the $5^{\circ}C$ with 5,000 cc non-perforated breathable film for MA storage in Salicornia herbacea at fresh cut distribution system. Fresh cut size 10 cm with 100,000 cc NPB film also had the good quality for 15 dyas storage at $10^{\circ}C$, and this result can be applied for short term distribution system in Korea.

• Development and Reproduction
• /
• v.19 no.2
• /
• pp.97-109
• /
• 2015

We assessed the effects of various dietary conditions on the growth, phenotypic traits, and morphometric dimensions of rock bream, Oplegnathus fasciatus and on the morphometric dimensions of sectioned olive flounder, Paralichthys olivaceus. Rock bream in the fed group increased in body weight, standard length, and condition factor, but these parameters decreased significantly for fish in the starved group (P < 0.05). The head connection dimensions of fish in the fed group decreased, while for starved fish there was increase in external morphometric dimensions (P < 0.05). In both species, sectioned morphometric analysis revealed that fish in the fed group had a larger body circumference and cross-cut sectional area, and greater cross-cut section height, relative to the starved group (P < 0.05).