• Tribology and Lubricants
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• 제24권4호
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• pp.170-178
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• 2008

In this paper, it is described how the problems appeared at the previous proto type sensor are improved. As changing the pressure and temperature of engine oil in a test rig, the modified sensor is tested. Then, the measured results of capacitance and the corresponding dielectric constants under various temperatures and pressures are shown. It turns out that the electrical signal gotten from the electrodes of newly developed sensor can be more stable under the various operating conditions.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.219-220
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• 2017

Current domestic waterproofing market in Korea mainly uses single-ply waterproofing materials comprised of coatings or waterproof sheets and two or more-ply composite waterproofing methods. In order to evaluate these types of composite waterproofing systems, a new test equipment and method that incorporates various deterioration conditions (joint displacement, chemical exposure, water pressure etc) was developed. In a comparison testing, the results showed that flexible type materials have higher response performance towards joint displacement than the hardened material. Furthermore, the importance of securing the stability of the waterproofing method in the vulnerable over-lap joint areas of waterproofing sheets is emphasized.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.400-405
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• 2008

Motor is energy converting system to generate mechanical force from electrical power and there are various typed motors in home, office, factory, vehicles, aircraft, shipping, etc. Recently in compliance with performance and reliability and the applications of variable speed motors with invert driver are expanded. Almost high power inverter have IGBT and IGBT's fault cause motor system fault. If we can calculate and foresee troubles of IGBT, we can protect accident caused by motor system fault. In this paper, the deterioration test method of IGBT devices is proposed and the test results of proposed method are shown by evaluated equipment. The basic concept of proposed method is current-voltage characteristic curve test between drain and source of IGBT in open state. The applied voltage type is ramp and it is confirmed that the current-voltage curvet pattern of IGBT in open state represents IGBT's deterioration state.

• 한국의류학회지
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• 제37권5호
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• pp.667-675
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• 2013

After analyzing excavated $17-18^{th}$ century silk fibers through a scanning electron microscopy, we discovered seven different kinds of fracture morphology. Using Morton & Hearle fiber fracture morphology, we classified the findings into four different categories. Type I is tensile failure resulting from brittle fracture, granular fracture, and ductile fracture. Type II is fatigue failure caused by tensile fatigue, flex fatigue, and axial split (fibrillation). Type III is bacterial deterioration discovered only in excavated artifacts. Type IV is a combination of the three above. Humid underground conditions and the infiltration of bacteria caused the fibers to swell and weaken its interfibrillar cohesion. Fractures occur when drying and processing an excavated artifact that is already in a fragile condition. Therefore, one must minimize damage through a prompt cleaning process and make sure that the least possible force is exerted on the fabric during any treatment for repair and exhibition.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.313-316
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• 2006

The most serious cause of deterioration in the concrete structures is reinforcing corrosion due to the chloride attack and carbonation. Therefore, it is needed to protect durability and performance according to the appropriate materials and methods in the concrete structures. In general, several types of polymer and silicate are used as protecting deterioration agents of concrete structures, but these agents have many problems because of low durability and properties. The object of this study is to develop a preventing aging technology. The work involves the development of silicate type penetration reinforcing agent.

• 보존과학회지
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• 제36권1호
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• pp.60-72
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• 2020

The Inscribed stones of Hanyangdoseong has been weathered for a long time because of external environment and living organisms. To establish a long-term conservation-management strategy for the inscription stones, the material characteristics of the inscription stones of Naksan Mountain Area were identified, and its deterioration state was diagnosed. Consequently, it was confirmed that the Inscription stones of Naksan Mountain Area mainly comprised coarse-to medium-grained pinkish granite and biotite granite, and, in part, comprised reddish granite, quartz porphyry, and aplite. Presently, the Inscription stones of Naksan Mountain Area, Hanyangdoseong, is undergoing a considerable decrease in physical properties because of physical, chemical, and biological weathering. Moreover, it has been confirmed that the type of damage, such as blistering, soiling, and dicolouration, on the surface shows a significantly high deterioration rate, and that conservation treatment might be required in future. In addition, because the possibility of damage recurrence is high even after the treatment, the conservation state must be regularly monitored.

• Computers and Concrete
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• 제6권6호
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• pp.473-490
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• 2009

This paper presents a new methodology to evaluate the load carrying capacity of deteriorated non-slender concrete bridge pier columns by construction of the full P-M interaction diagrams. The proposed method incorporates the actual material properties of deteriorated columns, and accounts for amount of corrosion and exposed corroded bar length, concrete loss, loss of concrete confinement and strength due to stirrup deterioration, bond failure, and type of stresses in the corroded reinforcement. The developed structural model and the damaged material models are integrated in a spreadsheet for evaluating the load carrying capacity for different deterioration stages and/or corrosion amounts. Available experimental and analytical data for the effects of corrosion on short columns subject to axial loads combined with moments (eccentricity induced) are used to verify the accuracy of proposed model. It was observed that, for the limited available experimental data, the proposed model is conservative and is capable of predicting the load carrying capacity of deteriorated reinforced concrete columns with reasonable accuracy. The proposed analytical method will improve the understanding of effects of deterioration on structural members, and allow engineers to qualitatively assess load carrying capacity of deteriorated reinforced concrete bridge pier columns.

• 한국조경학회지
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• 제25권4호
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• pp.39-50
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• 1998

The object of this study was to examine and analyze the environmental deterioration of three major trails and around peak area of Moaksan Provincial park in 1996. Trails are mostly made up at ridgeline and the slope of them is gentle. Mean trail width is 3.6m, and total length of branch trails is 982m in survey area. The environmental deterioration is derived from trail extension. Maximum eroded depth and cross-section area loss are 89cm and 14,050cm2 respectively, and gully erosion type appears at many sites. The environmental deterioration of trails is very heavy at the sections from Khui to Moaksan peak and from Moakchong to ascent part around the peak. The entire width, branch trail, maximum depth, cross-sectional area loss and surface roughness, as the indexes of trail conditions, are significantly greater at the more heavily used trails. Amount of erosion is influenced by eroded depth, longitudinal slope, runoff influence and entire width in descending order as well as the amount of use. Safety and protection facilities on the trail such as stone and soil stairs, rope handrail, stone channel and soil ditch work are built, but they are very deficient. Bared lands about 4,900m2 and fill slopes are caused and formed by recreation activities and constructions around peak area. It is required to carry the recess system and to conserve and rehabilitate the destroyed trail sites and bare fill slopes as soon as possible, before the environmental deterioration becomes critical because of increased used amount in consequence of construction of recreation parks.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.189-190
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• 2018

KS standards mostly relate to single component material evaluation, so in cases of underground structure environments, most cannot predict the existing composite forms of deterioration, resulting in the applied waterproofing materials becoming unable to respond to these damaging factors. Current domestic waterproofing market in Korea mainly uses single-ply waterproofing materials comprised of coatings or waterproof sheets and two or more-ply composite waterproofing methods. In order to evaluate these types of composite waterproofing systems, a new test equipment and method that incorporates various deterioration conditions (joint displacement, chemical exposure, water pressure etc) was developed. In a comparison testing, the results showed that flexible type materials have higher response performance towards joint displacement than the hardened material.

• Steel and Composite Structures
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• 제27권2호
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• pp.229-242
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• 2018

High strength steel is widely used in industrial applications to improve the load-bearing capacity and reduce the overall weight and cost. To take advantage of the benefits of this type of steel in construction, an innovative hybrid fabricated member consisting of high strength steel tubes welded to mild steel plates has recently been developed. Component-scale uniaxial and multiaxial cyclic experiments have been conducted with simultaneous constant or varying axial compression loads using a multi-axial substructure testing facility. The structural interaction of high strength steel tubes with mild steel plates is investigated in terms of member capacity, strength and stiffness deterioration and the development of plastic hinges. The deterioration parameters of hybrid specimens are calibrated and compared against those of conventional steel specimens. Effect of varying axial force and loading direction on the hysteretic deterioration model, failure modes and axial shortening is also studied. Plate and tube elements in hybrid members interact such that the high strength steel is kept within its ultimate strain range to prevent sudden fracture due to its low ultimate to yield strain ratio while the ductile performance of plate governs the global failure mechanism. High strength material also significantly reduces the axial shortening in columns which prevents undesirable frame deformations.