• The Korean Journal of Health Service Management
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• v.6 no.2
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• pp.71-80
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• 2012

The purposes of this study were to effect the upper extremities strength and ADL with upper extremities in frail elders. This study comparison upper extremities strength to pre-exercise and post-exercise and ADL with upper extremities. 30 elders who was in C silver hospital in Busan after resistance exercise during 12 weeks using elastic band, It was confirmed that improvement upper extremities strength and ADL with upper extremities after resistance exercise. As a result of study about effect of elastic band based resistance exercise on ADL of frail elders, it seems to have good effect on over all items(eating, dressing, bathing, make-up, go to a rest room). Therefore, it is necessary to find method about rehabilitation exercise for frail or partial disability elders.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.7-10
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• 2011

In this study, evaluation system of impact resistance performance is proposed. Compressive strength of concrete is 40, 60 and 80MPa. It evaluate impact resistance performance to use projectile 6, 7 and 8mm size. As a result, safety performance is more higher when the compressive strength is increased in. Compared with Hughes's formula, evaluation system of impact resistance performance is appropriated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.41-42
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• 2023

The physical performance of high-strength concrete deteriorates when exposed to high temperatures such as fire. In particular, in the case of ultra-high-strength concrete, there is a high possibility of explosion due to internal water pressure and thermal expansion due to the tight internal structure. In this paper, a fire resistance certification test was conducted for field application of ultra-high-strength fire-resistant concrete, and the fire resistance performance (temperature rise of main rebar) was compared according to the structural concrete cover thickness. As a result, when the covering thickness was 40 mm, three structures did not meet the certification standards, and when the covering thickness was 50 mm, all structures met the fire resistance certification standards.

• Geomechanics and Engineering
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• v.38 no.2
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• pp.165-177
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• 2024

Liquefaction phenomenon refers to a phenomenon in which excess pore water pressure occurs when a dynamic load such as an earthquake is rapidly applied to a loose sandy soil ground where the ground is saturated, and the ground loses effective stress and becomes liquid. The laboratory repetition test for liquefaction evaluation can be performed through a repeated triaxial compression test and a repeated shear test. In this regard, this study attempted to evaluate the effects of the relative density of sand on the liquefaction resistance strength according to particle size distribution using repeated triaxial compression tests, and additional experimental verification using numerical analysis was conducted to overcome the limitations of experimental equipment. As a result of the experiment, it was confirmed that the liquefaction resistance strength increased as the relative density increased regardless of the classification of soil, and the liquefaction resistance strength of the SP sample close to SW was quite high. As a result of numerical analysis, it was confirmed that the liquefaction resistance strength increased as the confining pressure increased under the same relative density, and the liquefaction resistance strength did not decrease below a certain limit even though the confining pressure was significantly reduced at a relatively low relative density. This is judged to be due to a change in confining pressure according to the depth of the ground. As a result of analyzing the liquefaction resistance strength according to the frequency range, it was confirmed that there was no significant difference from the laboratory experiment results in the basic range of 0.1 to 1.0 Hz.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.757-762
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• 2002

This study focused on the investigation of durability of latex modified concrete in the points of surface scaling resistance as cement types variated and latex content variated such as 5%, 10%, 15%, and 20%. An increasing the amount of latex produced concrete with increased flexural strength, but with slightly lower compressive strength. The increase in flexural strength might be attributed to the latex films between the hydrated cement and aggregates, and the decrease in compressive strength to the flexibility of the latex component named by Butadiene. The surface scaling resistance test was used to evaluate the durability of latex-modified concretes and rapid setting latex-modified concretes. The surface scaling resistance of LMC was quite good comparing to conventional concrete. Further, surface scaling resistance of RSLMC was improved with increasing the latex content.

• International Journal of Concrete Structures and Materials
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• v.10 no.4
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• pp.513-525
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• 2016

The resistance-demand approach has emerged as an effective approach for determining the shear capacity of reinforced concrete beams. This approach is based on the fact that both the shear resistance and shear demand are correlated with flexural tensile strain from compatibility and equilibrium requirements. The basic shear strength, under a given loading is determined from the intersection of the demand and resistance curves. This paper verifies the applicability of resistance-demand procedure for predicting the shear capacity of high strength concrete beams without web reinforcement. A total of 18 beams were constructed and tested in four-point bending up to failure. The test variables included the longitudinal reinforcement ratio, the shear span to depth ratio, and the beam depth. The shear capacity of the beams was predicted using the proposed procedure and compared with the experimental values. The results of the comparison showed good prediction capability and can be useful to design practice.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.3
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• pp.313-327
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• 1999

The aim of this study was to compare wear resistance of resin denture teeth opposing various restorative materials. The wear resistance of conventional acrylic resin teeth(Trubyte Biotone) and three high-strength resin teeth(Bioform IPN, Endura, SR-Orthosit-PE) opposing different restorative materials(gold alloys, dental porcelain, composite resin) was compared. Wear tests were conducted with a sliding-induced wear testing apparatus which applied 100,000 strokes to the specimen in a mesio-distal direction under conditions of 100 stroke/min and constant loading of 1Kgf/tooth. Wear resistance of the resin denture teeth was evaluated by the following criteria : 1) wear depth, 2) weight loss, and 3) SEM observation. Results were as follows. 1. When opposed to gold alloys and composite resin, high-strength resin teeth showed superior wear resistance compared to acrylic resin teeth. But, in cases opposing dental porcelain, differences between the wear of the high-strength and acrylic resin teeth were not statistically significant (p<0.05). 2. When comparing wear resistance among high-strength resin teeth, opposing gold alloys, Endura was slightly more resistant and while in cases opposing dental porcelain, SR-Orthosit-PE was showed to be slightly resistant(p<0.05). 3. The wear of high-strength resin teeth was greater by 5 to 7 times when opposing porcelain and 2 to 3 times when opposing composite resin compared to gold alloys(p<0.05). 4. SEM observations of the wear surface showed that wear of resin teeth opposing gold alloys is a fatigue type of wear and wear of resin teeth opposing dental porcelain is fatigue and abrasion type of wear. Trubyte Biotone showed more severe fatigue type of wear than high-strength resin teeth. In conclusion, the use of dental porcelain should seriously be considered as restorative material in cases opposing resin denture teeth and improvement seems to be needed on resin teeth in the areas of wear resistance.

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.129-135
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• 2010

The purpose of this research is to secure fundamental data on the application of fibre as a fire resistance method for more than 60 MPa high-strength concrete through an examination of mechanical properties and fire resistance performance. The results are as follows: 1) When there are less than 0.5~1.0kg/$m^3$ contents of PP and NY fibre for 60MPa and less high strength concrete, 1.0kg/$m^3$ contents of PP and NY fibre for less than 80MPa high strength concrete and 1.5kg/$m^3$ contents of NY fibre for more than 80MPa high strength concrete, the effect of fibre contents on workability and strength development is not significant. 2) Based on the result of a 3-hour fire resistance test for mock-up column, it is necessary to secure 50 mm of covering depth for the regulation of fire resistance performance of high strength concrete to the standards of The Ministry of Land, Transport and Maritime Affairs. 3) It is necessary to secure more than 400mm of column size for stable fire resistance performance.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.897-902
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• 2002

The failure of flat plate connection is successive failure process accompanying with stress redistribution, hence it is necessary to compute the contributions of each resistance components at ultimate state. In the present study, the interactions of resultant forces at each faces of connection, i.e. shear, bending moment and torsional moment are considered in the assessment of strength of slab. As a result the strength prediction model for connection is made up as combination of bending resistance, shear resistance and torsional resistance. The proposed method is verified by the experimental data and numerical data of continuous slabs.

• Journal of Pharmaceutical Investigation
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• v.26 no.3
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• pp.207-213
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• 1996

The kinetic change of electrical resistance of hairless mouse skin as a function of ionic strength of the bathing medium was determined from impedance measurements. After increasing (decreasing) the ionic strength of the bathing medium, resistance decreased (increased) continuously with time, finally reaching an equilibrium value. We have modelled this process, using nonsteady-state diffusion kinetics. The results show semi-quantitative correlation between theoretically derived and experimentally obtained values. Overall, this work provides further mechanistic insight into ion-conduction through the skin.