• Earthquakes and Structures
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• 제11권6호
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• pp.1101-1121
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• 2016

Base isolation, one of the popular seismic protection approaches proven to be effective in practical applications, has been widely applied worldwide during the past few decades. As the techniques mature, it has been recognised that, the biggest issue faced in base isolation technique is the challenge of great base displacement demand, which leads to the potential of overturning of the structure, instability and permanent damage of the isolators. Meanwhile, drain, ventilation and regular maintenance at the base isolation level are quite difficult and rather time- and fund- consuming, especially in the highly populated areas. To address these challenges, a number of efforts have been dedicated to propose new isolation systems, including segmental building, additional storey isolation (ASI) and mid-storey isolation system, etc. However, such techniques have their own flaws, among which whipping effect is the most obvious one. Moreover, due to their inherent passive nature, all these techniques, including traditional base isolation system, show incapability to cope with the unpredictable and diverse nature of earthquakes. The solution for the aforementioned challenge is to develop an innovative vibration isolation system to realise variable structural stiffness to maximise the adaptability and controllability of the system. Recently, advances on the development of an adaptive magneto-rheological elastomer (MRE) vibration isolator has enlightened the development of adaptive base isolation systems due to its ability to alter stiffness by changing applied electrical current. In this study, an innovative semi-active storey isolation system inserting such novel MRE isolators between each floor is proposed. The stiffness of each level in the proposed isolation system can thus be changed according to characteristics of the MRE isolators. Non-dominated sorting genetic algorithm type II (NSGA-II) with dynamic crowding distance (DCD) is utilised for the optimisation of the parameters at isolation level in the system. Extensive comparative simulation studies have been conducted using 5-storey benchmark model to evaluate the performance of the proposed isolation system under different earthquake excitations. Simulation results compare the seismic responses of bare building, building with passive controlled MRE base isolation system, building with passive-controlled MRE storey isolation system and building with optimised storey isolation system.

• 한국구조물진단유지관리공학회 논문집
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• 제23권6호
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• pp.120-131
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• 2019

본 연구에서는 빛 감성친화형 콘크리트에 광촉매를 적용하여 대기질 및 실내공기질을 개선하기 위한 LEFC 블록을 개발하고자 하였다. LEFC에 광촉매를 적용하게 되면 자외선 입사면 반대편에서도 투과로 인한 자외선이 존재하여 광촉매가 반응함으로써 일반 건축 자재를 적용한 경우보다 광촉매 반응효율이 크게 상승한다. 따라서 광촉매를 LEFC에 적용하기 위해 슬럼프, J-ring, L-box 테스트를 통한 자기충전성능을 평가하여 최적 배합을 결정하였고, 압축 및 휨 강도 시험을 통해 역학성능을 평가하였다. 그리고 TiO2 분포도를 확인하기 위해 SEM과 EDS 분석을 실시하였다. ALC골재와 단열재 적용으로 광촉매 사용량을 줄이고 단위중량을 감소시키는 방안을 활용하여 광촉매 효율을 증가시키는 빛투과 콘크리트 블록을 제작하였고, 향후 건조수축 등의 문제점 개선 및 NOx 제거 실험을 통한 LEFC 블록 성능 평가를 진행하고자 한다.

• 한국환경보건학회지
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• 제30권5호
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• pp.469-480
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• 2004

The radon concentrations were measured to survey distribution of radon concentrations in Seoul subway stations. The radon concentrations in air and water were measured at seventeen subway stations(Mapo, Chungjongno, Sodaemun, Kwanghwamun, Chongno3ga, Ulchiro4ga, Tangdaemun, Sangildong on Line 5;Nowon, Chunggye, Hagye, Kongnung, Taenung, Mokkol, Chunghwa, Sangbong, Myomok on Line 7) using the $RAdtrak^{TM}$ radon gas detector, Pylon AB-5 continuous passive radon detector and liquid scintillation counting method from January to May 1999. The major results obtained from this study were as follows: The long-term mean concentrations of radon were $61.8\;Bq/m^3$ in office, $78.9\;Bq/m^3$ in platform, $38.2\;Bq/m^3$ in concourse and $20.1\;Bq/m^3$ in outdoor, respectively. These levels were less than the action level ($148\;Bq/m^3$) of the U.S. EPA. The highest level of short-term mean concentrations was $116.55\;Bq/m^3$ at Chongno3ga station on the 5th line subway stations, while the lowest mean concentration was $19.55\;Bq/m^3$ at Mokkol station on the 7th line subway stations. The highest concentration of radon in the road water and storing underground water in the subway stations was $234.7\;KBq/m^3\;and\;155.5\;KBq/m^3$ in Sodaemun subway station, respectively. The results suggest that radon concentration in subway stations seems to be affected by ventilation and radon concentratin in underground water in the subway stations.

• KIEAE Journal
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• 제3권2호
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• pp.37-44
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• 2003

The aim of this study was to analyze the thermal performance through Test-Cell of TI-wall in domestic climate. This study was carried out as follows: 1) The TI-wall was studied for ability to reduce heat loss through the building envelope and analyzed to TIM properties. 2) Test models of TI-wall were designed through the investigation of previous paper and work, measured for winter and spring, and the thermal effects were analyzed. The type of the TIM used in test model is small-celled(diameter 4mm and thickness 50mm) capillary and cement brick(density $1500kg/m^3$) was used by thermal mass. 3) Test-cell of TI-wall was calibrated from measured data and the dynamic simulation program ESP-r 9.0. In these simulations, the measured climate conditions of TaeJon were used as outdoor conditions, and the simulation model of Test-cell was developed. 4) The sensitivity analysis is executed in various aspects with standard weather files and ESP-r 9.0, and then most suitable system of TI-wall are predicted. Finally, The suitable system of TI-wall was analysed according to sizes of air gap, kinds, thickness, and the surface absorption of therm wall. The result is following. In TI-wall, Concrete is better than cement brick, at that time the surface absorption is 95%, and the most efficient thickness is 250mm. As smaller of a air gap, as reducer of convection heat loss, it is efficient for heating energy. However, ensuring of a air gap at least more than 50mm is desirable for natural ventilation in Summer.

• 한국인터넷방송통신학회논문지
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• 제20권5호
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• pp.121-126
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• 2020

지구촌 곳곳에서 기후 온난화로 인하여 엄청난 환경적 재난이 매년 되풀이되고 있다. 에너지의 주공급원인 화석연료 과다 사용으로 지구 환경변화에 영향을 끼쳐 지구 생태계를 파괴하고 자원을 고갈시키고 있다. 이를 극복하기 위해서 신재생에너지의 개발을 통하여 탄소 배출량을 줄이려는 노력이 국내외적으로 활발히 연구되고 있는 게 현실이다. 이미 해외에서는 탄소 배출량을 줄이려는 신기술들이 심심치 않게 보도되고 있다. 제로 에너지 하우스는 고단열재 고기밀성 재료사용으로 저탄소 배출 및 에너지 사용량을 줄어들게 하고 최소한의 요구하는 에너지는 신재생에너지를 통해 공급받아 실거주가 가능한 모델이다. 이를 국내에서도 적용하려 노력 중이나 경제성이 떨어지기 때문에 보편화 되기는 어려운 실정이다. 본 연구의 목적은 친환경적 요소인 탄소 배출을 제로화 하고, 환기 시스템과 열교환기 및 에너지 저장장치를 공용으로 사용하여 제로 에너지 하우스의 시공 경제성을 확보하고, 창호 개방/폐쇠에 자동화 시스템을 부착하여 실내 적정온도 유지가 가능한 모델을 연구하고자 한다.

• 한국환경과학회지
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• 제16권3호
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• pp.323-331
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• 2007

Polycyclic aromatic hydrocarbons (PAHs) are well known for strong carcinogen. However, the human exposure analysis of PAHs is quite difficult and unreliable because of hard for estimation of actual expose dose. Then urinary 1-hydroxypyrene (1-OHP) has been a biological marker of exposure to PAHs. The purpose of this study was to investigate total amount from exposure to PAHs soused by indoor occupational exposure, and residence at Seoul metropolitan area and Kyeonggi province in Korea. Thirty-five housewives were included in this study from April 2003 through February 2004. Dietary habit and general characteristics such as age, type of building, existence of passive smoking, period of residence, fuel type for heating and ventilation type were obtained by self administered questionnaire. Urine samples were collected at morning and freeze quickly. Urinary creatinine was measured for converting into 24 hr urine. Concentration of the indoor PAHs was examined by NIOSH method number 5506. Urinary 1-OHP and PAHs were analysed by HPLC. Correlation coefficient between urinary 1-OHP levels and pyrene concentration of indoor air was 0.66 and statistically significant(P<0.01). The difference of urinary 1-OHP level due to dietary habits were not significant. Urinary 1-OHP level of Spring, Summer, Autumn, and Winter were $0.21{\pm}0.12,\;0.10{\pm}0.17,\;0.16{\pm}0.12,\;0.17{\pm}0.14{\mu}g/g$ cr, respectively. The arithmetic means of urinary 1-OHP for four season tee $0.16{\pm}0.14 {\mu}g/g$ cr. There was a trend that urinary 1-OHP level of residents who dwelling in apartment were higher compared with detached home, Comparison of 1-OHP level between heating by kerosene and LPG, Much higher gas heating type than kerosene type (P<0.05). This result implies that the urinary 1-OHP can be applied as the PAHs exposure indices.

• 한국환경보건학회지
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• 제49권2호
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• pp.78-88
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• 2023

Background: Exposure to volatile organic compounds (VOCs) can have acute and chronic health effects on human beings in general and in working environments. In particular, VOCs are often emitted in large quantities in industrial settings. In such circumstances, there is a need to improve the indoor air quality at workplaces. Objectives: The purposes of this study were to verify the effectiveness of air cleaning devices in workplaces and provide alternative solutions for improving working environments. Methods: Personal exposure and area level of VOCs for workers were evaluated in a car-part adhesive process before and after installing an air cleaning device with a TiO₂-coated filter. Passive samplers and direct reading instruments were used to collect and analyze the VOCs, and the removal efficiency and improvement of air quality were evaluated. We also calculated the exposure index (EI) to assess the risk level in the workplace. Results: The removal efficiency for VOCs through the installation of the air cleaning device was approximately 26.9~69.0% as determined by the concentration levels before and after installation. The measured substances did not exceed the exposure limits for the work environment and the EI was less than 1. However, carcinogenic substances such as benzene, formaldehyde, carbon tetrachloride, and trichloroethylene were detected. Conclusions: The application of an air cleaning device can be a solution for controlling the indoor air quality in a workplace, particularly in cases where ventilation systems cannot be installed due to process limitations.

• 한국콘텐츠학회논문지
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• 제17권1호
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• pp.183-192
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• 2017

본 연구는 흡연자와 비흡연자 모두를 위해 담배 연기로 인한 피해를 최소화하고 사용자에게 편안함을 줄 수 있는 흡연 부스를 디자인하기 위함이다. 연구방법으로 첫째, 흡연부스에 대한 의식조사, 둘째 제품 디자인에 대한 선호도조사, 셋째 감성어휘에 의한 흡연부스 감성평가 조사를 하였다. 흡연부스에 대한 의식조사결과, 대부분 모든 사람들이 터미널, 역에 흡연부스가 필요하다고 하였다. 디자인 선호도에 조사결과로 첫째, 외부 흡연자를 위한 디자인부스는 딱딱하고 투박한 이미지 보다는 멀리서도 알기 쉽고 거부감이 들지 않는 형태의 디자인으로 제작되어져야 한다. 둘째, 원색 계열의 색상보다는 화이트와 파스텔 톤의 난색계열 및 밝은 색상을 적용하여 디자인한다. 셋째, 흡연부스이므로 내부 순환 필터 문제가 잘 관리 될 수 있도록 한다. 감성어휘에 의한 감성평가결과 자극물에 대하여 4가지 차원으로 구분하여 인지하고 있었다. 각 인자의 함축 언어로 1인자에 대한 대표 이미지 언어는 '기능적 감정' 2인자의 대표 이미지 언어는 '심리적감정' 3인자의 대표 이미지 언어는 '색상감정' 4인자의 대표 이미지 언어는 '형태감정'으로 정의하였다. 흡연자와 비 흡연자 양쪽 모두를 위해 담배연기로 인한 피해를 최소화 시킬 수 있어야 하며 혼자만의 휴식을 취할 수 있는 사용자 중심의 서비스 디자인이 필요하다.

• 한국환경보건학회지
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• 제43권6호
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• pp.509-515
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• 2017

Objectives: The purpose of this study was to assess the indoor levels of $PM_{10}$, VOCs and aldehydes in nail shop and hair salon. Methods: The field survey was conducted for 52 hair salons 52 nail shops, and 26 shop-in-shops in Seoul and Daegu city. The field technicians investigated characteristics of each shop including operating time, indoor volume, ventilation and so on. Indoor concentrations of $PM_{10}$, VOCs and aldehydes, indoor temperature and humidity were measured in 12 hair salons, 12 nail shops and 6 shop-in shops. MP Surveryor II (Graywolf, USA) was used to measure $CO_2$ concentration, temperature and humidity for 8 hours. $PM_{10}$ concentrations were measured by minivolume air sampler with Teflon quartz filter ($0.2{\mu}m$ pore size, ${\varphi}$ 47 mm, Graseby-Anderson TEF-DISKTM) for 6 hours. VOCs passive sampler (OVM 3500) was used to collect VOCs for 8 hours and analyzed by GC/MSD. Results: The $CO_2$ concentrations were $759.4{\pm}58.2$ ppm in nail shops, $731.0{\pm}72.5$ ppm in hair salons, and $656.4{\pm}31.2$ ppm in shop-in-shops. The $PM_{10}$ concentrations were $27.5{\pm}14.2{\mu}g/m^3$ in nail shops, $33.1{\pm}6.3{\mu}g/m^3$ in hair salons, and $39.0{\pm}26.9{\mu}g/m^3$ in shop-in-shops. TVOCs concentrations were $3085.4{\pm}1667.8{\mu}g/m^3$ in nail shops, $2131.1{\pm}617.3{\mu}g/m^3$ in hair salons, and $1550.3{\pm}529.0{\mu}g/m^3$ in shop-in-shops. TVOCs concentrations in nail shops were significantly higher than those in hair salons and shop-in-shops (p=0.002). Formaldehyde concentrations were $60.8{\pm}36.6{\mu}g/m^3$ in nail shops, $89.1{\pm}55.4{\mu}g/m^3$ in hair salons, and $45.1{\pm}22.5{\mu}g/m^3$ in shop-in-shops. Conclusion: TVOCs concentrations in nail shop were the highest among others. TVOC concentrations in all stores exceeded indoor air quality stand of indoor air quality control in public-use facilities, etc act.

• 한국산업보건학회지
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• 제26권1호
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• pp.38-47
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• 2016

Objectives: The objective of this study was to determine the exposure levels of forklift operators to diesel engine exhaust(DEE) using black carbon(BC), elemental carbon(EC), and nitrogen dioxide($NO_2$) as indicators. Methods: A total of eight forklift operators in six collection companies were assessed over a period of two months from July to September 2015. BC was measured using a real-time monitor and respirable EC samples were analyzed using the NIOSH method 5040. $NO_2$ samples were collected using a passive badge-type sampler. Results: The geometric mean of BC, EC and $NO_2$ were $3.1-19.1{\mu}g/m^3$, $2.1-23.8{\mu}g/m^3$, and 12.5-166.6 ppb at all companies. When forklifts were operating both outside and inside, BC concentrations increased 2.0-5.6 times. The highest increase was observed when forklifts were operating indoors. The increase in BC concentrations varied by company(company A: 2.0 times, B: 3.2 times, C: 5.6 times, D: 2.1 times, E: 5.1 times, F: 2.6 times). The geometric mean of BC, EC, and $NO_2$ for the forklift operators was $9.6{\mu}g/m^3$, $7.9{\mu}g/m^3$, and 48.9 ppb, respectively. The geometric mean of BC, EC, and $NO_2$ for manufacturing workers was $9.3{\mu}g/m^3$, $0.9{\mu}g/m^3$, and 85.2 ppb, respectively. The mean BC and EC exposure levels for the forklift operators were slightly higher than those for manufacturing workers, but $NO_2$ levels for manufacturing workers were higher than those for the forklift operators(p>0.05). Multiple regression analysis revealed that diesel exhaust emissions standard, forklift weight and forklift manufacturer were the most influential factors in determining worker exposure. Conclusions: In the DEE work environment, workers who perform tasks within the workplace as well as inside forklifts as operators are likely to be exposed to a lack of ventilation. Further study of forklift operators' exposure to DEE indicators should be conducted to include a wider range of occupational and environmental situations, such as collection procedures, seasonal situations, types of fuel used, and number of forklifts.