• Journal of the Korea institute for structural maintenance and inspection
• /
• v.17 no.5
• /
• pp.105-112
• /
• 2013

In this study, the applicability of impact-echo method for assessment of residual strength of fire-damaged concrete is investigated. A series of standard fire test is performed to obtain fire-damaged concrete specimens. Impact-echo tests are executed on the specimens and the responses are analyzed. Compressive strengths of the fire-damaged concrete are evaluated and correlated with the ultrasonic wave velocities determined from the impact-echo responses. The effectiveness of impact-echo based ultrasonic wave velocity measurement for assessment of residual strength of fire-damaged concrete is discussed.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.2 no.2
• /
• pp.202-208
• /
• 1998

To investigae the effect of anchorage type of carbon fiber sheet (CFS) on flexural behavior of RC beams, the loading test of RC beams reinforced with CFS was conducted in variable of anchorage Type such as bolting anchorage and U type anchorage using CFS. This study can be summarized as follows ; It is confirmed experimentally that the bolting anchorage and U type anchorage with CFS is very effective to delay the bond failure and prevent the peeling of CFS. Also, the anchorage type applied with this study is very effective to improve the ductility compared with the improving of maximum flexural strength of RC beams. It is believed that the anchorage type used this study must secure the ductile capacity of above 3 for the flexural strengthening of RC beams. In the future, it is required to obtain the data about anchorage type of CFS for utilization of field work as well as investigate the ductile capacity of conventional study of anchorage type

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.2 no.2
• /
• pp.195-201
• /
• 1998

The purpose of this study is to evaluate the flexural strengthening effects of RC beams reinforced with carbon fiber sheets (CFS) in variable of strengthening amount and anchorage length of CFS. This study can be summarized as follows ; The CFS shares the tensile stress such as rebar during loading test. Also, as the strengthening amount of CFS is increased, the maximum flexural strength of RC beams reinforced with CFS is increased. Therefore, it is confirmed that the CFS's strengthening method is very effective to improve the flexural strength of RC beams. The maximum flexural strength of RC beams with CFS is determined by bond failure between CFS and concrete surface. So, the evaluation of CFS's strengthening effect can be calculated using the tensile stress of CFS which is peeling. When the anchorage length of CFS is increased, the ductility of RC beams is increased because of delaying the peeling of CFS. But, in case of same anchorage length of CFS, when the strengthening amount of CFS is increased, the ductility is decreased. Therefore, it is considered that the anchorage of CFS in the end zone is necessary.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.11 no.6
• /
• pp.193-200
• /
• 2007

The spalling analysis of high strength concrete columns needs a very complex and difficult process accounting for peeling of cover concrete as well as thermal, thermo-stress and hygro-transfer phenomena. However, the study on the spalling analysis method is insufficient. The practical spalling analysis algorithm is developed in this study, which formulates a vapor pressure equation as the parameter of temperature and cover depth and uses the compatibility condition In results of the spalling analysis, as the concrete strength increases and the content of PP fiber decreases the degree of spalling increases. This shows a similar result as the previous experimental study. Therefore the developed algorithm suggested in this study is expected to be useful in predicting the spalling of high strength concrete columns.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.12 no.3
• /
• pp.110-118
• /
• 2008

The use of FRP bar as reinforced concrete beams is considered as one of the most prominent solution that may overcome the corrosion of reinforcing steel bars. However, in the case of FRP reinforced concrete, both the reinforcing and the reinforced materials are brittle. For this reason, ductility of structures with FRP reinforcement is much less than that of structures with steel reinforcements. In this study, a method has been suggested to provide a meaningful quantification of ductility for concrete beams reinforced with FRP bars. This paper shows which the confinement to the compression concrete by the spiral can increase the ductility of FRP over-reinforced concrete beams.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.10 no.5
• /
• pp.171-178
• /
• 2006

It was presented that the spalling of high strength concrete exposed to high temperature could be reduced by using polypropylene fiber. However, as the concrete strength increase, the demanded quantity of PP fiber increase and this results in the loss of workability of ultra high strength concrete. The silica fume which is essentially mixed in ultra high strength concrete decrease the permeability of concrete, and this will increase the degree of spalling. In this study the effect of silica fume on the spalling of ultra high strength concrete and the fire resisting efficiency of PP fiber and poly vinyl alchol, instead of PP fiber, for the security of workability were experimentally examined.

• The Journal of the Korea Contents Association
• /
• v.12 no.8
• /
• pp.411-419
• /
• 2012

In case that R&D results from R&D projects are well managed and archived, the research institutes can transfer the valuable technologies related to R&D results with some costs to corporations. However, it is still difficult to maintain and reuse R&D results because they are managed by each person or each department and not integrated between R&D results. Therefore, the government should undertake to manage R&D results overall by collecting meta data and distribute analyzed information from meta data. Each researching institute also makes an efforts to manage R&D results focusing on their reusing. For this purpose, in this paper, we present a process to manage R&D results; insert meta data of R&D results to the system, upload files of R&D results to the database of the system, inquire, and use meta data of R&D results. Based on the process, we design a system architecture for managing R&D results. In addition, it should be mainly considered to design a global schema for integrating R&D results into one database. The system shows detailed information on R&D results and provides R&D results conveniently to users. We expect that we may reduce the cost of reusing R&D results and improve the quality of R&D results with designing efficiently a process and a global schema of R&D result management system.

• The Journal of the Korea Contents Association
• /
• v.9 no.3
• /
• pp.175-184
• /
• 2009

Korea shared 2.4% of world culture contents market in 2006 and ranked 9th. Therefore Korean government classified culture contents industry as a new growth-driving industries and started fixing the total contents policy promote system, exterminating illegal copying, protect copyright,improving contents creativity power, and supporting foreign market pioneering. Thus the importance of culture contents industry is increasing day by day. This study analyze the amount changes about production-inducing effect, value-added-inducing effects, employ-inducing effect, supply shortage effect and sectoral price effect, using inter-industry analysis according to time series. Especially, the sectoral price effect of culture contents industry increased by time pass. Thus, the influence of price changes in the culture contents industry to the other industries are increasing.

• Journal of Life Science
• /
• v.16 no.2 s.75
• /
• pp.297-301
• /
• 2006

For developing natural antibacterial agents from Houttuynia cordata Thunb., antibacterial effects of volatile flavor component using various bacterial sp. were tested. Extraction from Houttuynia cordata Thunb. by using SDE (Simultaneous steam Distillation-Extraction) showed strong antibacterial activities against Vibrio and Bacillus genus, such as Vibrio. cholerae, V. parahaemolyticus, V. vulnificus, Bacillus. cereus, and B. subtilis. Then chemical compositions of leaf and stem were analyzed. The contents of crude protein, lipid, and ash in stem were less than those of leaf, but fiber contents were higher than those of leaf. Among the amino acids, aspartic acid, glutamic acid, glycine, and arginine were higher than those of other amino acids. Linolenic acid, linoleic acid, oleic acid, and palmitic acid were major fatty acids. Major minerals of Houttuynia cordata Thunb. were potassium, calcium, phosphorus, magnesium, iron, zinc, and copper. Especially, in the case of potassium, it was highest.

• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.12
• /
• pp.2227-2238
• /
• 2000

The interfacial features of suspension system made of $CaCO_3$ particles have been investigated for the purpose of designing its effective treatment process. For the examination of variation of electrokinetic potential as a function of pH. the value of potential was observed to shift in the negative direction, which was thought to be due to the adsorption of hydroxide ion on the particle surface. Adsorption of surfactant on suspended particles resulted in the change of surface charge and shift in electrokinetic potential, which was dependent upon the sign of head charge and concentration of surfactant. Addition of inorganic salts affected stability of suspension greatly and sedimentation rate of suspension was influenced by the electric valence and amount of ions produced by dissolution of inorganic coagulants. DLVO theory made it possible to construct a energy profile diagram and a close correlation was found between experimental result and theoretically derived consequences. Non-specific adsorption of indifferent electrolyte resulted in the compression of electrical double layer and specific adsorption induced the shift of IEP and PZC in the opposite direction.