• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.2 s.54
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• pp.215-222
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• 2009

In this study, steel and FRP jackets are used to confine concrete cylinders. The FRP jacket behaviors compositely with concrete since there is bonding between them. However, the used steel jacket in this study do not behavior compositely with concrete since there is not an adhesive between them. The steel jackets are attached by external forces and the welding. This study suggests the measuring method of the axial strain for the confined concrete cylinders showing noncomposite behavior with the jackets and the correcting method of the measured strain for the composite-behavior jackets. For the noncomposite-behavior steel jacket, the axial strain of the steel surface does not represent the axial strain of the concrete inside. Also, a compressormeter can not be used. Thus, the two rigid plates at the top and bottom of a cylinder are placed and the distance of the two plates are measured and used for estimating the axial strain of the concrete. For the composite-behavior FRP jacket, the vertical strain measured on the FRP surface can be used for estimating the axial strain of the concrete. However, the vertical strain on the FRP surface contains the tensile strain due to the bulge of the concrete and, thus, the tensile strain should be corrected from the vertical strain. The corrected verticals strains compared with the measured strain or a existing constitute model; the result is satisfactory. The uncorrected stress-strain curves have the potential to under estimate the ductile behavior and the energy-dissipation-capacity of the composite-behavior FRP jackets.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.2
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• pp.363-372
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• 1996

A common site of fracture in maxillary complete denture is on the anteroposterior midline that coincides with the notch for relief of the labial frenum. Various approaches to reduce the incidence of this type of fracture have been suggested. The most widely used technique is the reinforcement of acrylic resin denture base with several solid metal forms. But few comparative studies on the efficacy of metal reinforcements have been reported. This study was conducted to compare reinforcing effects of commonly available metal reinforcements, which include wire, metal mesh embedded in the denture base and metal plate affixed to the impression surface of denture base by silicoating technique. This was load on the posterior. The strain gauges were oriented perpendicular to the anteroposterior midline of maxillary polished denture surface at one labial and the four palatal sites Non-renforced denture was used as control. The results were as follows : 1. In the non-reinforced denture group, only tensile strains on the palatal polished surface were observed. The tensile strains decreased in the order of incisive papilla, posterior denture border area, mid palatal area and rugae area. Compressive strain was observed on the labial polished surface. 2. As compared with the non-reinforced denture group, the metal plate or the metal mesh reinforced denture groups showed reduced palatal tensile strains,and the metal mesh reinforcement had a better reinforcing effect than the metal plate. But both reinforced denture groups showed no difference in the amount of compressive strain on the labial polished surface when compared to the non-reinforced denture group. 3. The metal wire positioned just above the labial notch decreased the compressive strain on the labial polished surface. But the presence of metal wires in the palatal polished surface caused increase in tensile strains in the area.

• The Plant Pathology Journal
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• v.25 no.4
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• pp.333-343
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• 2009

Here, we show that an endophytic bacterial strain, Enterobacter asburiae B1 exhibits the ability to elicit ISR in cucumber, tobacco and Arabidopsis thaliana. This indicates that strain B1 has a widespread ability to elicit ISR on various host plants. In this study, E. asburiae strain B1 did not show antifungal activity against tested major fungal pathogens, Colletotrichum orbiculare, Botrytis cinerea, Phytophthora capsici, Rhizoctonia solani, and Fusarium oxysporum. Moreover, the siderophore production by E. asburiae strain B1 was observed under in vitro condition. In greenhouse experiments, the root treatment of strain B1 significantly reduced disease severity of cucumber anthracnose caused by fungal pathogen C. orbiculare compared to nontreated control plants. By root treatment of strain B1 more than 50% disease control against anthracnose on cucumber was observed in all greenhouse experiments. Simultaneously, under the greenhouse condition, the soil drench of strain B1 and a chemical inducer benzothiadiazole (BTH) to tobacco plants induced GUS activity which is linked with activation of PR promoter gene. Furthermore, in Arabidopsis thaliana plants the soil drench of strain B1 induced the defense gene expression of PR1 and PDF1.2 related to salicylic acid and jasmonic acid/ethylene signaling pathways, respectively. In this study, for the main focus on root colonization by strain B1 associated with defense responses, bacterial cells of strain B1 was tagged with the gfp gene encoding the green fluorescent protein in order to determine the colonization pattern of strain B1 in cucumber. The gfp-tagged B1 cells were found on root surface and internal colonization in root, stem, and leaf. In addition to this, the scanning electron microscopy observation showed that E. asburiae strain B1 was able to colonized cucumber root surface.

• Journal of the Korean institute of surface engineering
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• v.26 no.2
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• pp.63-70
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• 1993

The mechanical properties of ferrite-martensited dual phases steels are affected by the microstructural factors, such as martensited volume fractions, ferrite grain size, strength ratio, connectivity, etc. Two phase alloys are technologically important. However, there is a lack of understanding as to stress-strain behavior of dual phase alloy in terms of stress-strain behavior of each component phases. The lack of the understanding stems from the complex deformation behavior of two phase alloys. The aim of this study is to rationalize stress-strain behavior of dual phase alloy in terms of the stress-strain behavior of component phase by systematically considering all the factors listed above. It was found that for a given martensite volume fraction, the calculated stress-strain curve was higher for a finer particles size than for a coarse particle sized within the range of the strains considered, and this behavior was seen for all the different volume fraction alloys considered. The calculated stress-strain curves were compared with corresponding experimental curves, and in general, good agreement was found. The maximum difference in flow stress between the calculated and the experimental results occurs at the nearly beginning of the plastic deformation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.546-551
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• 1997

In sheet metal forming, since the surface area of workpiece is apparently larger than the volume of it, the surface condition of the sheet metal is much varied. The formability of sheet metal is decided by the forming limit and the macroscopic suface defect as like fracture and wrinkle, and microscopic asponent, The factors affected in forming limit are stain herdening exponent, strain-rate scnsitivity exponent, anisotropic coefficient. The increasing of surface roughness is decresed the forming limit curve. It is known that the greater plastic deformation the more surface roughness by Kienzle, Osadaka. The purpose of this study is to investigate the influences of surface roughness in a uniaxial tension and the traperzoidal-shaped box drawing.

• Journal of the Korean Geotechnical Society
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• v.23 no.9
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• pp.17-28
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• 2007

Urban tunnels are usually important in terms of prediction and control of surface settlement, gradient and ground displacement. This paper has studied the application of strain softening analysis to predict deformation behavior of an urban NATM tunnel. The applied strain softening model considered the reduction of shear stiffness and strength parameter after yielding with strain softening effects of a given material. Measurements of surface subsidence and ground displacement were adopted to monitor the ground behavior resulting from the tunneling and to modify tunnel design. The numerical analysis results produced a strain distribution, deformational mechanism and surface settlement profile, which are in good agreement with the results of case study. The approach of strain softening modeling is expected to be a good prediction method on the ground displacement associated with NATM tunneling at shallow depth and soft ground.

• Tribology and Lubricants
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• v.24 no.2
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• pp.90-95
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• 2008

An elastic-plastic contact analysis is developed using a semi-analytical method. The elastic contact is solved within a Hertz theorem. The reciprocal theorem with initial strains is then introduced, to express the surface geometry as a function of contact stress and plastic strains. The irreversible nature of plasticity leads to an incremental formulation of the elastic-plastic contact problem, and an algorithm to solve this problem is set up. Closed form expression, which give residual stresses and surface displacements from plastic strains, are obtained by integration of the reciprocal theorem. The distribution of contact stress, residual stress and plastic strain are obtained by the changed surface geometry.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.721-725
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• 1996

The microfabricated test structures were used in order to evaluate the stress characteristics in films. The test structures were fabricated using surface micromachining technique, including HF vapor phase etching as an effective release method. The fabricated structures were micro strain gauge, cantilever-type vernier gauge and bridge for stress measurement, and cantilever for stress gradient measurement. The strain was measures by observing the deformation of the structures occurred after release etching and the amount of deformation can be detected by micro vernier gauge, which has gauge resolution of 0.2${\mu}{\textrm}{m}$. The detection principles and the degree of precision for the measured strain were also discussed. The characteristics of residual stress in LPCVD polysilicon films were studied using these test structures. The stress gradient due to the stress variation through the film thickness was calculated by measuring the deflection at the cantilever free end.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.03a
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• pp.117-120
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• 1997

Microstructure and pole figure through thickness in cold rolled sheet steel were investigated. The calculated plastic strain ratio in surface is greatly different with that in center layer and measured value in tensile test.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.161-168
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• 1999

A series of centrifuge model tests were performed in order to investigate the behaviors of various tunnel linings. A 1/100-scaled aluminum and hydrostone horseshoe tunnel linings with a radius km, height km were buried in a depth of C/D=3 with dry Joomunjin standard sand, the relative density of which was 86%. Bending moments and thrusts along the tunnel circumference were measured by 12 strain gages. Earth pressures in soil and on lining were estimated by pressure transducers, ground surface settlements at center and edges by using LVDTs. Average Ko(coefficient of earth pressure at rest) was 0.39 for the model sand. The structural behaviors of lining depended on its damaged conditions. But, as a rule, on the crown, the tensile circumferential strain of lining occurred at the inner surface, and the compressive at the outer surface, then positive bending moment was created at the crown. The circumferential strain of the inner surface on the springline was tensile, and the outer compressive, so negative bending moment was measured at the springline. For hydrostone linings, cracks initiated at the inner surface on the crown, and the outer on the springline over average 40g.