• The Journal of the Korea Contents Association
• /
• v.16 no.4
• /
• pp.114-122
• /
• 2016

Concrete is cost-benefit and high-durable construction material, however durability problem can be caused due to steel corrosion under chloride attack. Recently deicing salt has been widely spread in snowing season, which accelerates micro-cracks and scaling in surface concrete and the melted deicing salt causes corrosion in embedded steel. The previous governing equation of Fick's 2nd Law cannot evaluate the deteriorated surface concrete so that another technique is needed for the surface effect. This paper presents chloride penetration analysis technique for concrete subjected to deicing salt utilizing multi-layer diffusion model and time-dependent diffusion behavior. For the work, field investigation results of concrete pavement exposed deicing salt for 18 years are adopted. Through reverse analysis, deteriorated depth and increased diffusion coefficient in the depth are evaluated, which shows 12.5~15.0mm of deteriorated depth and increased diffusion coefficient by 2.0 times. The proposed technique can be effectively applied to concrete with two different diffusion coefficients considering enhanced or deteriorated surface conditions.

• Journal of Magnetics
• /
• v.16 no.2
• /
• pp.145-149
• /
• 2011

The coercivity $H_c$ of $Nd_2Fe_{14}B$ magnets and $Nd_2Fe_{14}B/(Nd_{0.7}Dy_{0.3})_2Fe_{14}B$ composite magnets were calculated by computer simulation based on the micromagnetic theory under assumptions that $Nd_2Fe_{14}B$ and $(Nd_{0.7}Dy_{0.3})_2Fe_{14}B$ grains have magnetically deteriorated layers on their surfaces and diffusion of Dy from $(Nd_{0.7}Dy_{0.3})_2Fe_{14}B$ grains to $Nd_2Fe_{14}B$ ones through the contacting boundaries recovers the magnetic anisotropy of the deteriorated layers of $Nd_2Fe_{14}B$ grains. $H_c$ of $Nd_2Fe_{14}B/(Nd_{0.7}Dy_{0.3})_2Fe_{14}B$ composite magnets increased by the diffusion of Dy from $(Nd_{0.7}Dy_{0.3})_2Fe_{14}B$ grains to $Nd_2Fe_{14}B$ ones and the resultant recovery of the anisotropy field of deteriorated layers of $Nd_2Fe_{14}B$ grains. The $H_c$ vs fraction of $(Nd_{0.7}Dy_{0.3})_2Fe_{14}B$ grains curve were convex for the magnets with the degree of alignment between 0.94 and 0.99, which suggests that the above composite magnets have larger $H_c$ values than the alloy-magnets with the same Dy content, and that we can save the consumption of Dy by using these composite magnets.

• Fire Science and Engineering
• /
• v.32 no.6
• /
• pp.63-68
• /
• 2018

In this study, to recognize the limitations and problems of fire safety in existing deteriorated buildings in Korea, and to analyze the fire case of Jongno Gooshiwon, the fire life safety assessment was performed and analyzed through fire egress simulation and analyzed the domestic and foreign related codes and regulations. In order to secure the fire safety of existing deteriorated buildings, it is necessary to adopt the systematic introduction and application of fire safety performance evaluation of buildings based on quantitative and objective indicated method for performance maintenance and management for fire life safety.

• Journal of Korean Living Environment System
• /
• v.21 no.6
• /
• pp.959-964
• /
• 2014

Energy performance of building envelope components, including external walls, floors, roofs, windows and doors, is crutial for determining how much energy is required for heating and cooling in a building. Among various building technologies, a green roof system can be a good option for reducing heat gain and loss in new buildings as well as existing buildings for green remodeling. This paper evaluates the performance of green roof systems according to soil depth and Leaf Area Index (LAI) for existing buildings. It also attempts to quantify the energy saving effects on new and existing buildings with different insulation levels. Thermal performance of green roofs is mainly dependent on soil thickness and LAI. Installation of green roofs in deteriorated existing buildings can lead to improvements in roof insulation, due to the soil layer. An increase in soil depth leads to a decrease in heating load, regardless of conditions of vegetation on the green roof. Larger LAI values may reduce cooling loads in the cooling season. Installation of green roof in deteriorated existing buildings showed bigger energy saving effect in comparison to a case in new buildings. A simulation study showed that the installation of green roof systems in deteriorated existing buildings with low insulation levels, due to low thermal performance requirements when constructed, could improve the energy performance of the buildings similar or better to the peformance on new buildings with the most updated insulation standard. Thus, when remodeling a deteriorated building, green roofs could be a good option to meet the most recent energy requirements.

• Journal of the Korean Wood Science and Technology
• /
• v.34 no.2
• /
• pp.1-9
• /
• 2006

The structural wooden members of the ancient building are deteriorated by fungi and termite over time. The deteriorate of the members causes the decrease of the specific gravity and the strength of it, so the stability of the building is threatened. Therefore, in this study, the evaluation of the specific gravity, which is correlated with the strength of the wood, was conducted in the post member using Nondestructive Evaluation (NDE) - Drilling Resistance Test (DRT). For the purpose of it, the specific gravity and drilling resistance of small specimens was measured to obtain the correlation between the specific gravity and the drilling resistance. And then, the drilling resistance test of the post members, which were expected to have the deteriorated parts, was performed. Consequently, the correlation between the specific gravity and the drilling resistance was very high ($R^2=0.89$) and the distributions of the specific gravity were evaluated for the each member. Also, the results were verified by the visual inspection of the cross section of it. Especially, the various variations of the wood member such as the deteriorated parts with termite or fungi and the crack could be detected exactly but the knot couldn't because the drill could pass by or could not penetrate the knot.

• The Journal of Korean Medicine
• /
• v.25 no.4
• /
• pp.226-234
• /
• 2004

Objective : The thyrotoxic periodic paralysis mainly appears in case of hyperthyroidism and the amyotonia is the characteristic main symptom. Through the deteriorated case and treatment by oriental medicine, the purpose of this research is to study the change of symptoms and the treatment effect for one case of a thyrotoxic periodic paralysis patient, Methods and Results : The treatment was carried out with oriental medicine as a main treatment and by the oriental medicinally deteriorated case, acupuncture treatment, moxibustion treatment and herbal medicine treatment were used as the main treatment methods. Also based on the symptoms which could appear with hyperthyroidism, the changes of symptoms were evaluated once a day with 4 levels of subjective scales that the patient was feeling, by dividing with 4 aspects of totalis symptoms, cardiovascular symptoms, musculoskeletal symptoms and other symptoms. In addition, it was shown that through the continuous hematologic test, the subjective and objective symptoms were mostly decreased during the treatment periods by comparing with the objective thyroid hormone (T3, T4, TSH) levels and the electrolyte levels. Conclusion : With this result, it was considered that oriental medicinal treatment was very effective for the thyrotoxic periodic paralysis through the oriental medicinally deteriorated case.

• KIEAE Journal
• /
• v.17 no.2
• /
• pp.5-12
• /
• 2017

Purpose: Under the purpose of presenting the adequate remodeling period for the improvement of thermal insulation performance of external walls in deteriorated buildings, the change in external wall and residential environment problem(dew condensation) due to aged deterioration after the apartments were constructed in Korea were analyzed. Method: Temperature Difference Ratio Outside(TDRo) and Heat Flow Meter(HFM) were used as measurement methods to evaluate the thermal insulation performance of deteriorated buildings. For TDR evaluation, thermo-graphic camera was used to measure and analyze the surface temperature of external wall. Also, dew condensation evaluation was analyzed using the Temperature Difference Ratio Inside(TDRi). Result: As a result of analyzing thermal performance through TDRo, the first decline point of thermal insulation performance began after 14-16 years have passed since construction was completed, and after 20 years have passed the decline point of thermal insulation performance reappeared. As a result of analyzing U-value with HFM measurement method, the decline rate of external wall's thermal insulation performance is lower than 2% in average at around 5 years after completion, and 8.7% in average at 10-15 years, and over 10.2% in average at 20 years.

• Magazine of the Korea Concrete Institute
• /
• v.10 no.6
• /
• pp.291-301
• /
• 1998

In this paper, two dimensional and three dimentional modeling techniques are proposed for the failure analysis of deteriorated reinforced concrete T-girder bridge subjected to cyclic loading up to failure. For the nonlinear failure anaysis, a tension stiffening model which can consider degradation of bond between reinforcement and surrounding concrete due to corrision of rebars in old bridge is proposed and a modeling technique for the supports conditions of the bridges which can consider degradation of bearing at supports in old bridge is also proposed, The analysis results along with comparisons with full-scale failure-test results confirm that finite element modeling techniques in this paper can be well applied to the failure analyses of in-situ old reinforced concrete T-girder bridges subjected to cyclic loading and the support condition modeling especially affects the bridge strength significantly.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.1 no.2
• /
• pp.44-50
• /
• 2010

The behaviour of Modular GFRP(Glass Fiber Reinforced Polymers) decks for use in deteriorated bridge decks replacement are investigated experimentally in this study. As for the performance evaluation of bridge decks, experimental studies on the 3 test specimens with 1/5 scale of full size were carried out. Three specimens were sandwich plates with box tube cores. The constituents of bridge decks were glass fiber preforms and epoxy resin. The experimental results of all the specimens were summarized for maximum strength, stiffness and deformation capacity. A finite element analyses were compared to verify validity of experimental results.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.6
• /
• pp.3969-3982
• /
• 2014

This study examined the QM(Quartier Management) Program of Germany for the Regeneration of Deteriorated Residential Blocks in Berlin. This study used basic data research for the 'Neighborhood Management Program' in South Korea. Therefore, German local documents, organization web sites, internal reports were analyzed to understand the status of the Germany's urban regeneration policies and present the conditions. This study was conducted by local interviews, e-mail exchanges and telephone interviews. The following were investigated and analyzed: 1) the present conditions of the urban regeneration policies and regional regeneration in Germany; 2) the characteristics of the QM program (Program's strategy, funding and utilization plans, program's applicable areas, Indicators for regional selection); and 3) examine two cases of the QM Program in Berlin.