• Corrosion Science and Technology
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• v.4 no.4
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• pp.147-154
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• 2005

The creep resistance of geogrids is one of the most significant long-term safety characteristics used as the reinforcement in slopes and embankments. The failure of geogrids is defined as creep strain greater than 10%. In this study, the accelerated creep tests were applied to polyester geogrids at various loading levels of 30, 50% of the yield strengths and temperatures using newly designed test equipment. Also, the new test equipment permitted the creep testing at or above glass transition temperature($T_g$) of 75, 80, $85^{\circ}C$. The time-dependent creep behaviors were observed at various temperatures and loading levels. And then the creep curves were shifted and superposed in the time axis by applying time-temperature supposition principles. The shifting factors(AFs) were obtained using WLF equation. In predicting the lifetimes of geogrids, the underlying distribution for failure times were determined based on identification of the failure mechanism. The results confirmed that the failure distribution of geogrids followed Weibull distribution with increasing failure rate and the lifetimes of geogrids were close to 100 years which was required service life in the field with 1.75 of reduction factor of safety. Using the newly designed equipment, the creep test of geogrids was found to be highly accelerated. Furthermore, the time-temperature superposition with the newly designed test equipment was shown to be effective in predicting the lifetimes of geogrids with shorter test times and can be applied to the other geosynthetics.

• Tribology and Lubricants
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• v.23 no.6
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• pp.266-271
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• 2007

The brake performance of sintered friction materials for the high speed train was studied. In this study, newly developed sintered materials based on copper were compared with the commercial products for high speed trains. They were tested on a 1/5 scale dynamometer using low carbon steel disks. Effectiveness, fade, and recovery tests were carried out to examine friction performance and the change of disk thickness variation (DTV) during brake applications and noise propensity were also evaluated. Results showed that the two sintered friction materials exhibit similar friction coefficients and braking performance, whereas the newly developed friction material was superior in terms of DTV generation and noise propensity to the commercial friction material. The improvement of the newly developed friction material was attributed to the high graphite content which reduced the stick-slip phenomena and prevented uneven disk wear by producing friction films on the counter disk.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.401-402
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• 2002

Diesel engines have many sliding parts with solid body contact. For example, a piston-ring and a cylinder bore, a valve and a valve-seat, a cam and a valve tappet. These parts have a severe wear problem. during engine life times. During these times, the valve tappet has abnormal wear such as scuffing and pitting due to a high hertzian contact stress between the cam and the tappet. Excessive wear problems frequently occur to both the cam and the tappet. To solve these problems, we developed an advanced wear resistant tappet. The developed tappet consisted of a hard-metal wear part and a steel body. To increase a bonding strength, those two parts, were directly bonded to each other. Also to decrease a bonding temperature, we developed the composition of Ni-binder materials in the hard metal. To estimate the wear characteristics of the newly developed tappet, we performed wear tests and engine dynamo tests in order to compare them with a conventional Fe-base tappet. As a result, the newly developed tappet has better wear characteristics than those of the conventional tappet. In addition, we performed a 100,000km field-test, and the newly developed tappet showed much improved wear resistance.

• Journal of Environmental Health Sciences
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• v.33 no.2 s.95
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• pp.98-103
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• 2007

This study was performed to measure the changed concentrations of formaldehyde and volatile organic compounds after moving in the newly constructed apartment buildings at Seoul. From December 2004 to October 2005, we measured the concentration of formaldehyde and volatile organic compounds in newly constructed apartment buildings before and after residence. In conclusion, it showed that there was a significant relationship association between the con centration of the volatile organic compound and the formaldehyde and remodeling of the house, built in-furniture, and ventilation of the house. Therefore, it was suggested that we need preventive measures and management plans about various factors such. as remodeling, and built in-furniture, ventilation to decrease the concentrations of volatile organic compounds and formaldehyde.

• Journal of the Korean housing association
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• v.24 no.2
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• pp.97-104
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• 2013

This study involves 2 newly built apartment houses which are A with 23 floors as 150 mm slab width and B with 16 floors as 180 mm slab width. The impact was added by tapping and bang machine at the middle floor level of these 2 apartments and the test was arranged in terms of the characteristic of vibration and sound level which transferred to upper or down floors. As a result, impact floor shows the highest value in terms of both sound and vibration level and followed was at down floor of the Impact floor. Also, blocking function for the lightweight and heavyweight floor impact sound level was tested for each room of the apartment A and B including living room, main room, room 1 and 2. As a result, sound blocking function of B apartment was better than that of A and the function was getting worse when the room size is getting smaller.

• Journal of the Society of Disaster Information
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• v.4 no.1
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• pp.86-100
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• 2008

It is needed to classify the kinds of construction and demolition(c&d) debris to 6 catagories of waste concrete, waste asphalt concrete, waste wood, scraps, combustible waste and incombustible waste in order to properly do a separate discharge and to estimate unit generation rate in construction site. Also, in this case, the unit treating cost for mixed wastes should be applied with the unit treating cost for combustible waste. The construction standard materials estimation data is used for basic data for estimating unit generation rate. The mixed wastes in this data should be classified to waste wood, combustible waste and incombustible waste, and their ratio is obtained by using the unit generation rate of Asia Pacific Environment and Management Institute and Seoul Metropolitan Development Institute. The waste amounts generated from newly-built construction can be obtained from multiplying the loss rate by the amount of materials used from construction standard estimation data. Also, those from dismantling construction can be obtained by subtracting waste amount generated during newly-built construction from total input amount of materials in newly-built construction. Those in two cases can be used in construction site. It can be used for estimating the amount generated and establishing the treating plan in the case of setting up the policy of waste management and doing the environment impact assessment.

• Journal of the Korean housing association
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• v.22 no.5
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• pp.81-90
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• 2011

The purpose of this study is to examine if orientation, location of entrance, court yard of existing old houses are consistently maintained when houses are newly built fitting the changed lots system, and the changed road system for Topdong 'Yangdalmal' in the existing old settlements in old center Cheongju. The lots was spilt up into 15 lots in 1913, 38 lots in 1968, and 75 lots in 2010. Among them, The lots maintained are 19 lots and the lots subdivided are 56 lots. 12 houses are newly built among the 19 shape-maintained lots and 41 houses are newly built among the 56 split up lots. Most of the new houses have south-facing orientation. Main entrance near the old road keeps the direction of the previous entry. Houses built in 1970s and 1980s keep their original court yards but they are disappearing year by year by new type of houses in 1990s.

• Korean journal of applied entomology
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• v.35 no.4
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• pp.287-296
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• 1996

Twenty four newly recorded and rarely known noctuid species from the Korean peninsula, which are preserved in domestic and foreign museums, are discussed in this article. Eleven species; Hypenodes curvilinea Sugi, Polydesma boarmoides (Guenee), Catocala bokhaica (Kononenko), Xanthomantis contaminata (Draudt), Craniophora harmandi (Poujade), Amphipyra acheron Draudt, Orthogonia tapaishana (Draudt), Chasminodes u.ssurica Kononenko, Oncocnemis campicola Lederer, Protomiselia bilinea (Hampson) and Xestia (Anomogyna) albonigra (Kononenko) are newly reported from the Korean peninsula. Among them, P. bilinea (Hampson), which has been known in Japan, is reported for the first time from the Continental Asia. The occurrence of Athetis pallidipennis Sugi, Pseudocosmia maculata Kononenko, Callopistria miracula Herz and Lacanobia dentata Kononenko are reconfirmed in Korea. Eudocyma salamina (Cramer) and Polydesma boarmoides Guenee are .considered to be tropical migrating species. A previously misidentified species, Hypenodes rectifascia Sugi is corrected as H. curvilinea Sugi.

• Journal of the Korean Home Economics Association
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• v.44 no.3 s.217
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• pp.103-113
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• 2006

The purpose of this study was to determine the present condition of sick house syndrome of newly built apartments a mid-sized city. The questionnaire survey was carried out from $19^{th}\;to\;22^{nd}$ of May 2004, with respondents consisting of 160 households living in two apartment complexes of Cheongju. Their residency periods after moving in were within $six{\sim}ten$ months. From the survey results of the respondents, sick house syndrome items revealed high percentages with the highest value of 49.3%. The respondents answered that they knew relatively well about sick house syndrome but they had no knowledge about 'bake-out'. The response percentages of sick house syndrome items in E complex, consisting of $106m^2$ (32 pyeong) size units, were significantly higher than those in A complex, consisting of $76m^2$ (23 pyeong) size units. This result suggests that the pollution levels emitted from interior materials in larger sized apartment units are higher than those in small sized units. The response percentages of sick house syndrome items in houses with fulfilled ventilation which had been ventilated before or after moving in were lower than in houses not ventilated.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.8
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• pp.649-655
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• 2006

The recent indoor air quality problem in a newly-built apartment house is resulted from the improvement of airtightness performance and the use of the building material contained harmful chemical substances. As a result, these cause indoor air quality gradually to become worse and the harmful effect on occupant health called Sick House Syndrome. The most effective solution to improve the indoor air quality is to encourage the use of green building material. However, if the house is built with general building material, ventilation with outdoor air is alternative to dilute the pollutant concentration. The purpose of this re-search is to find optimum ventilation time in a newly-built apartment house at which the ventilatoris installed. It is found that the HCHO and toluene concentrations are remarkably decreased with the elapse of ventilation time and the concentration reduction rate is increased with increment of air change rate after one hour after operating the ventilator.