• Journal of The Korean Society of Agricultural Engineers
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• v.56 no.6
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• pp.63-73
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• 2014

In this study, the large scale test was performed to investigate the behavior of failure on the embankment and spillway transitional zone by overtopping. The pore water pressure, earth pressure, settlement and failure behaviors according to several reinforcing method were compared and analyzed. The pore water pressure showed a small change in the spillway transition zone and core, indicating that the riprap and geotextile efficiently reinforced the embankment, but non-reinforcement showed a largely change in pore water pressure. The earth pressure by riprap and geotextile at upstream slope and bottom core increased rapidly with the infiltration of the pore water by overtopping. And the earth pressure at crest showed a smally change due to effect of the inclined core. A settlement by riprap showed a small change and the geotextile decreased a rapidly due to failure of crest. The width of failure by riprap at intermediate stage (50 min) showed a largely due to sliding of crest. But, the width and depth of the seepage erosion after the intermediate overtopping period (100 min) were very small due to the effect of riprap than geotextile and non-reinforcement which delayed failure. It has the effect that protect reservoir embankment from erosion in the central part. The pore water pressure at the spillway transition zone due to overtopping increased a rapidly in the case of non-reinforcement, but the reinforced methods by geotextile and riprap showed a smally change. Therefore, the reinforced method by riprap and geotextile was a very effective method to protect permanently and the emergency an embankment due to overtopping, respectively.

• Textile Coloration and Finishing
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• v.27 no.4
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• pp.334-339
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• 2015

Polyketone fiber, a newly developed high strength fiber, has a tenacity and modulus similar to the paramid fiber, and can be used for reinforcing mechanical rubber goods(MRG), such as tires, hoses, and technical textiles. In addition, aliphatic polyketone, which has excellent strength, modulus, chemical stability and reasonable price, is being developed only in South Korea. It will be expected for replacement of super fiber such as aramids and increasing the technical textile market share. This paper surveys the mechanical properties of polyketone fiber yarn for technical textiles. For this purpose, two kinds of yarns are prepared, mechanical properties of coated and uncoated polyketone yarns such as tensile strength, elongation and modulus were examined before and after weather resistance test(temperature $60^{\circ}C$, humidity 60%, amount of power $0.67w/m^2$). The differences of mechanical properties between uncoated and coated yarns for high functional technical textiles and composite materials are estimated through this study.

• The Journal of Engineering Geology
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• v.15 no.1
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• pp.77-86
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• 2005

CFRD(Concrete Faced Rockfill Dam) is in widespread use because this type of dam has superior characteristics in structural, material aspects comparing with earth cored rockfill dam. On this paper, up-to-date re-searches and techniques are summed up to be available for future needs in design and construction of CFRD. For example, such items as embankment using weak rock, experience of sand-gravel fill CFRD, connecting slab applied between plinth and face slab, raising experience of old dm, inverse filtration problem, environmental friendly zone, thickness and reinforcing of face slab, alluvial foundation treatment, and curb element method, are summarized for understanding of related engineers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.68-77
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• 2012

The joint of existing steel grid composite deck is composed of lap splice of reinforcing bar with end hooks and field-placed concrete. In this study, bending tests of deck joint composed of concrete shear key and high tension bolts are carried out for the design variable, concrete shear key strengthened with steel plate or not, and test results are compared with flexural performance of the existing deck joint. Test results showed that the mechanical deck joint has about 30% ~ 60% more ultimate bending strength than the existing joint. According to analysis results of moment-curvature relationship, the initial bending stiffness of the existing deck joint is some higher than that of mechanical joint. But, after crack failure the structural performance of the existing deck joint is rapidly reduced. Furthermore, the deck joint with the strengthened shear key with steel plate has more bending moment capacity than the deck joint without strengthening. And strengthening of shear key has positive influence on the increase of bending stiffness.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.5
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• pp.109-115
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• 2008

As structures are getting super-rise and large-sized, introducing the construction methods such as prefabrication of bar-meshes and complex method are being actively discussed to pursue the high quality of reinforced concrete, the simplification of field works, and the reduction of duration, as well as the study on how to connect reinforcing rods, which occurs while applying the same methods, is in progress Also, the pressure welded joint is a kind of method that heats the ends of reinforced bars locally and joint them, and after the pressure welding, the vulnerable part in the reinforced bar occur. Thus, in the construction field, the throughout quality control is necessary because of the delayed duration and the lowered construct ability. In this study, of the traditional lap splice method and the mechanical splice one, the screw coupler, we tried to look into through experiments the prefabrication method of bar-meshes, a typical joint method usually used for the joint parts for PSC structures applying the reinforced bar with its big diameter, and a newly-developed up-set coupler method. And we also examined the characteristic of tensile.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.48-58
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• 2014

In this study, quasi-static according to the displacement-controlled (strain control) method tests on RC columns for seismic reinforcement performance in accordance with the provisions of the seismic design and construction before 1992 design code for highway bridges in korea. Used reinforcement that improves the performance of Inorganic Helical Bar, a kind of alloy steel, circular columns were tested outside the seismic reinforcing. In the experiment, fracture behavior, lateral load-displacement relation, ductility and energy assessment evaluation was performed through tests. The variables in experimental are section force of reinforcement, spiral reinforcement spacing, reinforcement method. Improved seismic performance and effect were confirmed through quasi-static test experiments. The results of study confirmed determination the appropriate size of reinforcement, reinforcement forces, spacing and selection of the type required, furthermore, not only mechanical reinforcement but also substitution of high-strength concrete reinforced with concrete cover improved seismic performance.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.1
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• pp.75-83
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• 2014

In order to prevent brittle failure of concrete, steel fiber reinforcement is effective composite material. However ductility of steel fiber reinforced concrete may be limited due to shrinkage caused by large content of cement binder. Chemical prestressing for steel fiber reinforcement in cement matrix can be induced through expansive admixture and this can increase reinforcing effect of steel fiber. In this study, mechanical performances in concrete with CSA (Calcium sulfoaluminate) expansive admixture and steel fiber reinforcement are evaluated. For this work, steel fiber reinforcement of 1 and 2% of volume ratio and CSA expansive admixture of 10% weight ratio of cement are added in concrete. Mechanical and fracture properties are evaluated in concrete with steel fiber reinforcement and CSA expansive admixture. CSA concrete with steel fiber reinforcement shows increase in tensile strength, initial cracking load, and ductility performance like enlarged fracture energy after cracking. With appropriate using expansive admixture and optimum ratio of steel fiber reinforcement, their interactive action can effectively improve brittle behavior in concrete.

• Journal of Korean Home Economics Education Association
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• v.12 no.3
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• pp.19-38
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• 2000

This study is about open and secondary level Home Economics Education which is applicable to field and which includes the characteristics, purpose and problems of each open education, secondary education and home economics education. Based on the ideology of open education this study will identify the meaning of openness in terms of Home Economics Education reconstructing meaning purpose, characteristics, curriculum paradigm and curriculum. The instructional model and module which use web, will be presented as the results o the reconstruction works. The open instructional module in Home Economics Education which will be operated on the web is consisted of 1) setting the orientation of curriculum development 2) instructional model development 3) rebuilding the Home Economics Education curriculum 4)development of instructional modules and web-based materials and 5)construction of the web-site. Six instructional module begin with critical/emancipatory curriculum paradigm in open Home Economics Education use module as a unit of class management instead of 1 class, facilitates nest-type integration which is applied from open education keeping the nature of Home Economics Education and focus on practical problem and problem solving through reconceptualization with dialectical perspective on individual, family and society. The practical problem solving model has four steps: Identifying practical problems. Understanding the contexts of problem, Searching for solutions and examining its consequences, Action and evaluation. The web-site has to be developed based on the six instructional module includes those issues : self-identification for reinforcing autonomy and self-esteem, living with family living with friends, autonomous living healthy living and understanding sexuality.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.1
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• pp.257-263
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• 2011

Recently as AR(Augmented Reality) is focus of attention, AR is applied to various fields and is expected its valuable use. In this paper, we implemented the system based on Goblin XNA which supports high resolution model file and higher AR. We confirmed the relation of model output among the number of marker, the location and changes of camera distance. And we produced the infantile studying contents using AR and embodied. In implemented contents, we showed the familiar character to infants on each page marker. As the result of it, we can raise their concentration and at a time studying supporters can use the contents easily as well. Also we put 3 marker on each page of contents to recognize it smoothly in case one part of it is hidden by any obstacle. Finally we maximized the learning effect such as presence and immersion in studying through reinforcing 3D models according to the every situation.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.71-80
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• 2015

Steel stiffener is required for reinforcing the structure of the window frame made of versatile but weak PVC material. Steel stiffener however becomes a source of greater heat loss and frequently plays a role of thermal bridge due to its high thermal conductivity. To maintain thermal resistance similar to PVC frame, steel stiffener is perforated to reduce the effective heat transfer area. To compensate the structural strength of the steel stiffener which is weakened by the perforation, the thickness is increased. Increase in thickness will also increase the thermal heat resistance. Five samples which are PVC frame, PVC frame + original steel stiffener, PVC frame + 30% perforated steel stiffener, PVC frame + 50% perforated steel stiffener, PVC frame + 65% perforated steel stiffener are modeled and simulated for 2nd moment of area and thermal resistance. Therm/window version 6.3 is used for thermal analysis. The results show that among the five samples analyzed, PVC frame + 65% perforated steel stiffener best satisfies both structural strength and thermal resistance.