• Proceedings of the Korean Geotechical Society Conference
• /
• 2010.09a
• /
• pp.1253-1257
• /
• 2010

그라우팅은 건설공사에서 지반의 갈라진 틈이나 공동, 공극 등에 적절한 충전재를 압력을 이용하여 주입하는 것으로, 굴착공사 시 누수방지와 불안정한 지반의 보강을 위하여 광범위하게 사용되고 있다. 가장 많이 사용되고 있는 그라우팅 주입재의 재료로는 물유리계를 주재료로 사용하는 약액주입공법이 많이 사용되어지고 있다. 기존의 물유리계 재료를 사용할 경우 발생하는 용출현상 및 강도저하를 보완하기 위하여 가소성을 부과한 무기질계 재료ECG(Eco Clean Grouting)를 사용하여, 강도 및 내구성이 우수하고 주입재의 용출 현상이 발생하지 않아 환경오염 문제가 거의 없는 영구적인 차수 및 보강에 적합한지와 친환경적 특성을 확인한다. 본 연구는 가소성 무기질계 재료인 ECG(Eco Clean Grouting)재료를 사용하여 현재 많이 사용되는 재료인 물유리계 재료로 일축압축강도, 체적변화, 내구성 평가, 투수시험, 어독성 시험, 용탈시험등을 수행하여 비교 분석 하였다. 일축압축 시험결과 재령 28일 강도는 ECG가 물유리재료에 비해 크게 발현되었고, 내화학성시험 결과 ECG의 길이변화율이 거의 없는 것으로 내화학성에서 강점을 보였다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.2
• /
• pp.142-148
• /
• 2007

The purpose of this study is to suggest the effective ventilation strategies and control methods that can minimize energy cost maintaining acceptable IAQ level in apartment house. The effects of the air-cleaning and heat-recovery ventilation system on IAQ under various operating conditions are investigated based on the experimental and CFD analyzed results. The results can be summarized as follows. (1) When a ventilator is not operated, the concentration of several pollutants may highly show in the house even though environment-friendly building materials are applied. Therefore, a mechanical ventilation system is required to obtain proper ventilation. (2) The pollutant concentration is noticeably deceased under air-cleaning/ventilation mode of air-clinic system, however, pollutant of kitchen is stagnant, because fresh air is not carried into the kitchen. (3) When air-clinic system is only equipped at master bedroom and living room, the system does not effectively deliver fresh air throughout the whole house, and then high pollutant concentration is obtained in each room. In contrast the average pollutant concentration meets the guideline when air-clinic system is installed at each room. (4) The air-cleaning/ventilation mode significantly affects on room ventilation in comparison with ventilation mode only.

• Korean Journal of Construction Engineering and Management
• /
• v.9 no.4
• /
• pp.84-91
• /
• 2008

"Eco-friendly construction" is an emerging issue in the building industry. Main purpose of the eco-friendly construction is to sustain the health and environment of building residents and to minimize the harmful effect on their environment. Apartment residents have great concern on eco-product, since many cases are reported that Sick Building Syndrome is caused by toxic substance from building materials. Environmental performance is to meet through using the highest grade eco-friendly materials. However, generally eco-friendly materials are more expensive than normal materials, Therefore, using eco-friendly materials at public housing project is limited to economical aspect. The purpose of this paper is development of eco-friendly material selection model considered cost efficiency. The selection of Eco-friendly finishing materials and their methods are constructed to consider environmental performance level and cost index compositively. Development of eco-friendly material selection method is economic and reasonable one when public housing is constructed.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.11
• /
• pp.1161-1169
• /
• 2008

The removals of TCE and PCE vapor with or without a supply of toluene as a primary substrate were compared in a biofiltration process, and the variations of microbial communities associated with the removal were also investigated. As a result of investigations on the removals of TCE/PCE in a biofilter B within which TCE/PCE-acclimated sludge was attached on the surface of media without a supply of primary substrate, and those in another biofilter A where toluene-acclimated sludge was attached with a supply of toluene as a primary substrate, followings were found: (i) parts of microbes responsible to the decomposition of toluene vapor participate in the removal of chlorinated VOCs such as TCE and PCE, and (ii) effective biological removals of TCE and PCE vapor do not necessarily need cometabolism. Sequencing of 16S rDNA obtained from the band profile of DGGE (Denaturating Gradient Gel Electrophoresis), it was confirmed that: (i) uncultured alpha proteobacterium, uncultured Desulfitobacterium, uncultured Rhodobacteraceae bacterium, Cupriavidus necator, and Pseudomonas putida were found to be toluene-decomposing microbes, (ii) alpha proteobacterium HTCC396 is a TCE-removing microbe, (iii) Desulfitobacterium sp. is a PCE-decomposing microbe, and (iv) particularly, uncultured Desulfitobacterium sp. is probably a microbe decomposable not only toluene but also various chlorinated VOC vapor including TCE and PCE.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.3
• /
• pp.263-278
• /
• 2022

This paper contains experimental study for the development and performance of TBM backfill material with thixotropic properties. The LW backfill material is widely applied to fill the cavity on the back side of the shield TBM excavation, but has disadvantages such as settlement caused by strength reduction, material separation by groundwater, and reduced plasticity. In this paper, laboratory tests and a model test were conducted to assess the performance of inorganic thixotropic backfill material proposed to improve these problems. The results of laboratory tests show that 1 hr-uniaxial compressive strength of ITB was 12 times higher than LW, and the rate of bleeding of 20 hr was 8.3 times lower, and the result of flow table test was more than 27 times higher. This result indicated that the inorganic thixotropic backfill material has superior properties to LW backfill in terms of strength reduction, material separation, and thixotropy. In the model experiment, a model injection device tester was manufactured and the injection performance and filling rate were verified. When material was injected in the water, it was visually checked whether material separation occurred, and it was confirmed that the filling rate was 96% or more. Comparison results with the test of LW and ITB materials was concluded that ITB can reduce the material separation by groundwater and the occurrence of tunnel cavity.

• Korean Institute of Interior Design Journal
• /
• v.14 no.1
• /
• pp.91-99
• /
• 2005

The chief aim of this study is to prepare the rational alternative plan of the environmental friendly intoner design which can improve sick house syndrome of an apartment house and clarify future-development and the method proposal of use activation and point out the present problem depended to investigate development and the use actual condition of domestic environmental friendly interior materials related in-and-outside-the-country example on a foundation about the various precedence researches on environmental friendly interior materials. The study was witten at first the concept of the environmental interior design which leads environmental friendly charactenstics of material, a interior design, and construction, at the first in the conceptual definition of sick house syndrome. and then it was introduced the present condition of domestic environmental interior materials, interior design and construction and an environmental regulation and standard of in-and-outside-the-country In Conclusion, it may try to present comprehensive analysis and an expansive alternative plan.

• Journal of the Architectural Institute of Korea Structure & Construction
• /
• v.34 no.12
• /
• pp.57-63
• /
• 2018

The purpose of this study was to confirm the effects of flush-out on the reduction of Volatile Organic Compounds(VOCs) concentration in newly built residential buildings. The field measurements were conducted in two complexes of multi-residential buildings which are located suburban areas of Seoul. About three samples of residential buildings were selected in the field measurements. Two samples, B and C, had been flush-out with outdoor air more than seven days. The sample A was maintained at same condition during the flush-out because of the comparison. The indoor concentrations of VOCs in the three samples were measured at three times, before, during, and after flush-out. From the field measurements, it was confirmed that two samples' indoor VOCs' concentrations were considerably decreased after the flush-out comapred with those of the sample A in which the flush-out was not conducted. The decreases of indoor VOCs concentrations were corresponding to about 50% ~ 92% of the concentrations of before. Through the reviews for the previous studies, it was also found that the reduction effects of the flush-out is similar with the those of the bake-out which were reported in the previous studies.

• Journal of Life Science
• /
• v.26 no.3
• /
• pp.331-337
• /
• 2016

Although fibroblast growth factor 23 (FGF23) is exclusively produced in osteoblasts and osteocytes, its main target is the kidney, where it decreases phosphate reabsorption by suppressing Na-phosphate cotransporters. Independently of its action on phosphate homeostasis, FGF23 also inhibits bone formation in vivo. In a calvarial osteoblastic cell model, FGF23 was shown to negatively affect extracellular matrix mineralization. This study investigated whether FGF23 had similar effects on osteoblast maturation, including differentiation and mineralization of bone marrow-derived mesenchymal stem cells (MSCs). D1 MSCs were cultured in an osteogenic medium containing β-glycerophosphate, ascorbic acid, and dexamethazone. Osteoblastic differentiation was evaluated by alkaline phosphatase (Alp) staining, and matrix mineralization was evaluated by alizarin red staining and calcium deposition. The expression of differentiation-stimulating genes Runx2, Alp, and osteocalcin and mineralization-inhibiting genes Enpp1 and Ank was analyzed using semiquantitative RT-PCR. Supraphysiological doses of FGF23 did not stimulate proliferation or osteoblastic differentiation of MSCs. Matrix mineralization 1, 2, and 3 weeks after the FGF23 treatment did not vary between control and FGF23 groups, although time-dependent enhancement of mineralization was obvious. Calcium deposition was also unchanged after the FGF23 treatment. mRNA expression levels of differentiation- and mineralization-related genes were also similar between the groups. Despite these negative findings, FGF23 signaling through FGF receptors seemed to function normally, with phosphorylation of the Erk protein more evident in the FGF23 group than in controls. These findings suggest that unlike calvarial osteoblasts, FGF23 is not likely to affect osteoblastic differentiation and mineralization of MSCs.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
• /
• v.15 no.4
• /
• pp.24-31
• /
• 2019

In this paper, we simulated a new apartment building by using radon emission test values from various building materials used as interior finishing materials. The simulations evaluated the radon concentration in the room according to the radon emissions and the ventilations for each type of finishing material (gypsum board, stone, tile and concrete). Overall concrete finish simulation case showed the highest concentration than the case using other materials due to the effect of wall area at the center of each room and the mean radon concentration at 1.5 m above the floor was slightly lower than the mean value at each center. In the case of the porch, pantry and bathroom, the radon concentration was high even when the same materials were used as in the other rooms.

• 보일러설비
• /
• no.3 s.158
• /
• pp.144-147
• /
• 2007

원자재 가격 상승과 달러화 약세 등의 영향으로 내수시장과 수출시장 모두에서 어려움을 겪고 있는 보일러 제조업체들이 일제히 환기시장으로 눈을 돌리면서 시장 쟁탈전이 뜨거워 지고 있다. 실내공기 오염악화를 이유로 공동주택과 관련 시설 등에 대한 환기시스템 설치를 의무화하는 '다중이용시설 실내공기질 관리법'이 지난해 발효되면서 주택 환기시스템 관련 수요는 매년 확대될것으로 전망되고 있기 때문이다. 실제로 환기시장 규모는 2004년 500억원대에서 2005년1000억원 규모로 성장했고 지난해에는 2200억원대를 기록했다. 업계관계자들은 올해 환기시장의 규모를 약 3500억원대로 예상하고 있고 내년에는 5500억원대까지 성장할 것으로 전망하고 있다. 이에 따라 이 시장에 진출한 보일러사들은 일제히 신제품을 발표하고 나섰고 최근에는 경동나비엔과 대성쎌틱이 새롭게 시장에 진입한 상태다. 주요 보일러사들이 출시한 환기시스템의 특장점과 마케팅 방향등에 대해 알아봤다.