• International Journal of Highway Engineering
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• v.10 no.1
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• pp.105-115
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• 2008

It is known that the long-term behavior and performance of jointed concrete pavement due to slab curling are affected by the environmental factors such as temperature, moisture, and so on. However, any relationships between the curling and its factors have not been defined clearly yet because of insufficient detailed investigation. The temperature, relative humidity, strain, vertical displacement of a concrete slab, and horizontal movement of its transverse joints were investigated by various sensors and devices instrumented in the slab of a concrete pavement section constructed for this study. The constraint of the curling by joint stiffness was investigated in addition to effect of the temperature and moisture on the early aged concrete slab by analyzing the field data measured for approximately 4days from concrete placement. The curling of the concrete slab showed 24hour cycles mainly because of the temperature effect, and the upward curling gradually increased because of the long-term effect of drying shrinkage of the concrete. The magnitude and variation of the curling were significantly affected by the joint stiffness which is comprised of aggregate interlocking and other factors. The effect of the variation of the seasonal joint stiffness varying with the temperature and long-term drying shrinkage on the slab curling will be investigated as a further study.

• Journal of Veterinary Clinics
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• v.24 no.1
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• pp.56-58
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• 2007

This study was attempted to find appropriate surgery for gill cover curling disorder in arowana. Gill cover curling is a usual clinical findings in arowana, which often lead to death of the fish by dyspnea. Two different surgical methods were implemented in this study for gill cover by using cutting and incising fm-like fer two silver arowana. The surgery was identified to be successful since the fish healthily recovered. This experiment demonstrated that gill cover curling can be cured by using surgery.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.793-798
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• 2011

In this study, it was grasped to the flow characteristics of cutting fluid injected by nozzle installed in high pressure holder for avoiding chip curling occurred during machining process. And for avoiding chip curling, the possibility of elimination under various chip conditions was checked. Consequently, the highest discharging pressure and velocity was shown in 150 of nozzle inflow angle. Also as nozzle outlet diameter is small, the pressure and velocity of injected flow are high. Moreover, It could be confirmed that width and thickness of chip have no direct effect on chip elimination and it is achieved by torque generated by injected cutting fluid.

• International Journal of Highway Engineering
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• v.8 no.3 s.29
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• pp.155-162
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• 2006

Deflections of jointed concrete pavements at test road are monitored during 48 hours. And methods of calibration with respect to curling deflections are suggested. Relations between deflection ratio of center to joint at test time and deflection ratio of center at test time to center at reference time are described by regression. From deflections at test time, deflections transformed to reference time which gives minimum deflections in a day are estimated through regression curves and concluded to propose as a alternative method of curling calibration with more data accumulation.

• 한국도로학회:학술대회논문집
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• 2009.11a
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• pp.81-87
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• 2009

• Journal of Korea Entertainment Industry Association
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• v.13 no.1
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• pp.111-119
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• 2019

The purpose of study was to evaluate the economic evaluation of Chuncheon curling stadium. In oder to estimate economic evaluation, benefit/cost ratio, net present value and internal rate of return were used. Additionally, in order to investigate the socio-economic spread effect, literature review and input-output analysis were used. The results of study were as follows. First, as a result of analyzing the demand for curling stadiums in Chuncheon, it was believed that the construction of the stadium will attract athletes from the Chuncheon region as well as athletes from Seoul, Incheon, Gyeonggi Province and North Chungcheong Province. Second, economic validity analysis showed that the initial investment did not make sense, but the players' training and competitions and the advantages of the potential experience of curling events for citizens in nearby areas, including Chuncheon, make the construction and operation reasonable. Third, as a result of the review of the social and policy validity of the curling stadium, the project to build a curling stadium in Chuncheon was secured with a policy validity as a public sports facility necessary for both professional and living athletes. Finally, the analysis of socio-economic spread effect of curling stadiums had shown that it would have a positive effect on the level of satisfaction of the general public as well as the discovery of elite athletes.

• Journal of Korean Society of Steel Construction
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• v.21 no.5
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• pp.527-536
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• 2009

The purpose of this experimental study was to investigate the block shear fracture behavior and curling effect on a single shear-bolted connection in thin-walled carbon steel fabricated with four bolts. The specimens that fail by block shear were planned to have a constant dimension of the edge distance perpendicular to the loading direction, bolt diameter, pitch, and gage. The main variables of the specimens were plate thickness and end distance parallel to the loading direction. A monotonic tensile test was carried out for the bolted connections, and the ultimate behaviors, such as the fracture shape, ultimate strength, and curling, were compared with those that had been predicted using the current design specifications. The conditions of curling occurrence in terms of plate thickness and end distance were also investigated, and the strength reduction due to curling was considered.

• Journal of Korean Society of Steel Construction
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• v.30 no.2
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• pp.87-96
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• 2018

This study is aiming at investigating the ultimate behaviors and curling influence on the ultimate strength in high strength aluminum alloys (7075-T6) single shear two-bolted connections using finite element analysis. The validation of finite element analysis for predicting the ultimate behaviors was verified through the comparison between previous test results and analysis predictions. Strength reduction due to curling occurrence was estimated quantitatively. Parametric analyses with extended variables were conducted and the conditions of curling occurrence according to end distance and edge distance were suggested. Finally, modified equation was suggested considering curling influence on the ultimate strength of aluminum alloys 7075-T6 bolted connections.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.55-61
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• 2012

In this study, it was grasped to the flow characteristics of injection nozzle installed in high pressure holder for improving productivity. Chip curling occurred during cutting process for difficult-to-cut material detracts product qualities and productivity. Among of method preventing the phenomenon, high pressure injecting cutting oil is an alterative. In this study, the optimal nozzle was designed by CFD method and it was conducted to analyse on the effect of high pressure injection on chip shape generated during cutting process and wear of insert by experimental method. As the result, it could be confirmed that high pressure injection is favorable for preventing chip curling and insert from wearing.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.5
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• pp.55-63
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• 2018

Recently, the use of duplex stainless steel which with a two-phase microstructure (equal mixture of ferrite and austenite) has been increased in a variety of industrial fields due to higher strength leading to weight saving, greater corrosion resistance(particularly, stress corrosion cracking) and lower price. However, currently, stainless steels are not included in the structural materials of Korean Building Code and corresponding design standards are not specified. In this paper, experimental studies have been performed to investigate the structural behaviors of duplex stainless steel (STS329FLD) bolted connection with two bolts for providing the design data. Main variables are shear connection type (single shear and double shear) and end distance parallel to the direction of applied force. Fracture modes at the final step of test were classified into typical block shear fracture, tensile fracture and curling. Curling occurrence in single shear connection led to ultimate strength drop by up to 20%. Test strengths were compared with those by current design specifications such as AISC/AISI/KBC, EC3 and AIJ and proposed equations by existing studies. For specimens with no curling, Clement & Teh's equation considering the active shear plane provided a higher strength estimation accurancy and for specimens with curling, Kim & Lim's equation considering strength reduction by curling was also overly unconservative to predict the ultimate strength of curled connections.