분말활성탄 혼입률에 따른 수성도료의 특성

최병철 ( Choi Byung-cheol ),경인수 ( Kyoung In-soo ),이상수 ( Lee Sang-soo ) 한국건축시공학회 2020 한국건축시공학회 학술발표대회 논문집 Vol.20 No.2

Recently, as people's interest in environmental pollution increases, interest in indoor air pollution as well as outdoors is increasing. Accordingly, this study prepares functional paints by mixing powder activated carbon, which is a porous material, into aqueous paints, and examines the adsorption performance of volatile organic compounds (VOCs) and formaldehyde (HCHO). As a result of the experiment, the concentration of volatile organic compounds (VOCs) and formaldehyde (HCHO) tended to decrease as powder activated carbon was incorporated. It is believed that physical adsorption was achieved by the micropores of powdered activated carbon. However, in the adsorption test method, it is judged that the concentration was affected by the inflow of outside air as the chamber cover was opened to put the test object in the empty chamber where a certain concentration was maintained.

분말활성탄을 혼합한 도료의 도장횟수에 따른 흡착 특성

최병철 ( Choi Byung-cheol ),경인수 ( Kyoung In-soo ),이상수 ( Lee Sang-soo ) 한국건축시공학회 2021 한국건축시공학회 학술발표대회 논문집 Vol.21 No.1

Due to COVID-19, the spread of non-face-to-face culture is increasing the time spent indoors. Accordingly, it is necessary to reduce indoor air pollutants. Also, among building materials, there are paints. As the number of coatings increases, the coating film becomes thick, and there is a risk of cracking and falling off. Therefore, this study is to examine the adsorption properties of indoor air pollutants according to the number of coatings of a paint mixed with powdered activated carbon. In the experimental plan, the addition ratio of powdered activated carbon was selected as 30%, and the number of coatings was selected as primcoating, second coat, and finishing coat, and the concentration of formaldehyde and volatile organic compounds were measured. As a result, as the number of coatings increased, the concentration of formaldehyde and volatile organic compounds tended to decrease. This is considered to be due to the fact that not only the physical adsorption acted by the internal pores of the powdered activated carbon, but also because a lot of powdered activated carbon was present on the painted surface as the coating film was formed. However, since it is judged that there is an error in the concentration due to the inflow of external air as the chamber cover is opened to put the test object in the adsorption test process, it is considered that the experimental method needs to be supplemented.

커피 부산물을 활용한 시멘트 경화체의 특성

최병철(Choi, Byung-Cheol),이상수(Lee, Sang-Soo) 대한건축학회 2021 대한건축학회 학술발표대회 논문집 Vol.41 No.1

입상형 활성백토의 입자크기에 따른 수성도료의 특성

최병철 ( Choi¸ Byung-cheol ),이상수 ( Lee¸ Sang-soo ) 한국건축시공학회 2021 한국건축시공학회 학술발표대회 논문집 Vol.21 No.2

In order to reduce the emission of harmful substances that degrade indoor air quality, the Ministry of Environment strengthened the standards for the content of VOCs in paints to supply and sell eco-friendly paints. In this related study, an eco-friendly paint mixed with a powder-type absorbent material was prepared and its characteristics were reviewed. As the amount of powder-type absorbent material increased, the workability (viscosity, peeling, etc) decreased. Accordingly, this study aims to examine which particle size is suitable according to the particle size of the granular adsorbent while improving the problem of the powdery adsorbent by using the granular adsorbent. As an experimental plan, the particle size of granular activated clay is selected to be 0.250, 0.425, 0.710(mm), and the decrease rate of VOCs concentration and impact resistance are reviewed. As a result of the experiment, as the particle size of the granular activated clay increased, the decrease rate of the VOCs concentration increased and the impact resistance improved. Therefore, considering the problems that occur after actual painting, the particle size of granular activated clay of 0.425mm is suitable.

발수제 종류에 따른 코팅된 커피찌꺼기를 치환한 모르타르의 압축강도 및 흡수율

최병철 ( Choi Byung-cheol ),김규용 ( Kim Gyu-yong ),편수정 ( Pyeon Su-jeong ),지성준 ( Ji Sung-jun ),이예찬 ( Lee Yae-chan ),남정수 ( Nam Jeong-soo ) 한국건축시공학회 2023 한국건축시공학회 학술발표대회 논문집 Vol.23 No.1

In order to reduce the high absorption ratio of spent coffee grounds, this study examined the compressive strength and absorption ratio of mortar replacing coated spent coffee grounds according to the type of water repellent. In order to examine this, as the water repellent used, a silane-based water repellent (fluorine-based water repellent) and an acrylic-based water repellent, which are film-type water repellents, and a silane/siloxane-based water repellent, which are penetration-type water repellents, were used. The spent coffee grounds were coated with each of three water repellents, and mortar was prepared by mixing cement and fine aggregate. As a result of the experiment, the compressive strength and absorption ratio of the mortar replaced with coated spent coffee grounds coated with the film-type water repellent were superior to the penetration-type water repellent. Therefore, in order to reduce the high absorption ratio of spent coffee grounds, a suitable water repellent is a film-type water repellent. Among them, it is judged that the acrylic type has excellent water repellency and is suitable.

실내 공기질 개선을 위한 광촉매를 혼입한 수성도료의 특성

최병철 ( Choi Byung-cheol ),박채울 ( Park Chae-wool ),경인수 ( Kyoung In-su ),이상수 ( Lee Sang-soo ) 한국건축시공학회 2020 한국건축시공학회 학술발표대회 논문집 Vol.20 No.1

As the modern society enters, the building becomes sealed and the public's interest in the environment increases, so the interest in indoor air pollution increases and the environmental pollution is raised as an important issue not only outdoors but also indoors. In addition, the emergence of sick house syndrome (SHS) has increased the interest in formaldehyde and is a cause of deteriorating indoor air quality. Accordingly, this study prepared a functional paint by incorporating a photocatalyst in an aqueous paint, and conducted formaldehyde adsorption experiments and functional evaluation. As a result of the experiment, as the photocatalyst was added, the formaldehyde adsorption performance tended to increase. In addition, as a result of measuring the impact resistance and alkali resistance according to the KS standard, there is no difference in residual cracks and cracks between the water-based paint without the photocatalyst and the water-based paint with the photocatalyst added. Therefore, it is considered that the water-based paint added with a photocatalyst can improve the indoor air quality by adsorbing formaldehyde and can be used as a functional paint because the functionality is not different from that of a general water-based paint.

한국 상장 외국기업의 이익조정에 관한 연구

최병철(Byung chul Choi),최현정(Hyun jung Choi),문두철(Doo cheol Moon) 한국공인회계사회 2016 회계·세무와 감사 연구 Vol.58 No.2

한국에 상장된 외국기업들은 본사와 영업장소가 외국에 있지만, 재무제표에 대해서는 한국감사인이 회계감사를 하고 있다. 한국감사인이 외국기업을 감사할 때는 상대적으로 물리적, 언어적, 문화적, 법적 제약요인에 부딪히게 된다. 따라서 감사인이 제한된 감사시간과 감사기한 내에 효과적으로 충분한 감사증거를 수집하여 재무제표에 대한 신뢰성을 확보하기가 상대적으로 어렵다는 특성이 있다. 그런데 현재 한국에 상장된 외국기업들은 과거 특정 외국기업의 대규모 분식회계 및 상장폐지로 회계투명성에 대한 의문을 지속적으로 제기 받고 있다. 따라서 본 연구는 한국감사인이 한국증시에 상장된 외국기업들을 감사할 때 상대적으로 취약한 감사환경으로 인해 경영자의 이익조정동기를 효과적으로 통제하지 못하여 재무제표의 신뢰도와 회계투명성이 떨어지는 지에 대하여 분석하였다. 한국 상장 외국기업들의 재무제표를 통해 한국기업과 비교검증 해 본 결과, 외국기업들은 한국기업에 비해 재량적 발생액을 통한 이익조정행위가 더 크게 나타났다. 하지만 발생액을 통한 이익조정과 상호 보완·대체 관계에 있다고 알려진 실제이익조정 측정치에 대한 결과는 유의미하지 않았다. 이는 여러 가지 제약요인에 의해 외국기업에 대한 감사인의 감사절차가 충분하지 못해 외국기업들의 재무제표에는 더 많은 이익조정이 나타날 것이라는 가설을 지지하는 결과이다. 한국 상장 외국기업의 경우 발생액을 통한 이익조정으로도 충분히 경영자의 이익조정동기가 실현가능하여 미래 경영실적에 부정적 영향을 미칠 수 있는 실제이익조정까지는 사용하지 않는 것으로 판단된다. 본 연구는 한국에 상장되어 있는 외국기업들의 재무제표 신뢰성이 낮다는 실증결과를 보여주어 감사인이 충분한 감사시간을 확보하고, 더욱 엄격한 입증절차 수행으로 회계투명성과 재무제표 신뢰도 제고를 위한 노력을 해야 한다는 것을 시사하고 있다. 또한 한국상장 외국기업의 투자자를 보호하기 위한 제도적 장치를 마련하고, 외국기업이 한국증시에 신규상장 할 때 회계투명성에 대한 더욱 엄격한 심사가 필요하다는 것을 금융당국과 거래소에 제시하고 있다. This paper investigates accounting transparency of foreign firms listed in the in Korea Exchange using Accrual and Real activity-based earnings management measures. Head office and place of business of Foreign firms in Korea Exchange are physically far from Korea. So, Korean auditors encounter some limitations for audit because there are many differences for audit environment between Korean firms and foreign firms physically, linguistically, culturally and legally. Auditors who audit foreign firms have more difficulty in collecting sufficient and proper audit evidences than auditors who audit korean firms. In this regard, this study analyzes whether foreign firms manipulate earnings more than Korean firms. The sample consists of 53 firm-years from 14 foreign companies which are traded in KOSPI and KOSDAQ and 6,578 Korean companies from 2011 to 2014. The difference of discretionary accruals (DA) between foreign firms and korean firms is statistically significant. But the difference of real earnings management (REM), which is an another proxy of earnings management, is not statistically significant. We conduct an additional analysis to avoid possible biases from small sample size by matching foreign firms with Korean firms in the same industry. Our results are robust with regards to the matched sample. The results provide evidence consistent with the hypothesis that accounting transparency of foreign firms listed in the Korea exchange is lower than Korean firms. Because a small number of foreign firms have been public in the Korea exchange, this study cannot collect enough number of sample. Even with this limitation, this study gives a implication to investors when using financial statements of foreign firms in the Korea exchange. Also, results of this study suggest a necessity of institutional measure for investor protection.

입상형 활성백토의 첨가율에 따른 수성도료의 특성

최병철(Choi, Byung-Cheol),이상수(Lee, Sang-Soo) 대한건축학회 2021 대한건축학회 학술발표대회 논문집 Vol.41 No.2

As the amount of the powder-type adsorbent used for paint increases, the workability deteriorates. Therefore, the workability is improved by using the granular adsorbent. Accordingly, the experimental plan is to examine the properties of water-based paints according to the addition ratio of granular activated clay. As a result of the experiment, the concentration of VOCs decreased as the addition ratioof granular activated clay increased. In addition, alkali resistance and impact resistance were improved. Therefore, it is judged that workability is improved if the addition ratio of granular activated clay is 50%.

Methyl Methacrylate(MMA)계 도로보수재의 기초 물성 평가

최병철 ( Choi Byung-cheol ),김규용 ( Kim Gyu-yong ),편수정 ( Pyeon Su-jeong ),지성준 ( Ji Sung-jun ),유하민 ( Eu Ha-min ),남정수 ( Nam Jeong-soo ) 한국건축시공학회 2023 한국건축시공학회 학술발표대회 논문집 Vol.23 No.2

Domestic ultra-hard road repair materials require a lot of time before the road can be opened to traffic. Therefore, in this study, Methyl Methacrylate (MMA) based road repair material was used to improve the above problems. Furthermore, the basic physical properties of MMA-based pavement repair materials are examined to confirm their suitability in concrete pavements. For this study, two types of MMA road repair materials (A type and B type) were selected. Then, the curing of the test specimens prepared for painting was carried out under three conditions. The experimental items were viscosity (drop time) and drying time (set to touch, dry-hard). As a result of the experiment, viscosity (drop time) was faster in type A than in type B. The drying time results were as follows. In the case of set ti touch, both type A and type B dried in about 10 minutes regardless of the curing conditions. In the case of dry-hard, regardless of the curing conditions, A type dried longer than B type, but it dried faster than conventional road repair materials. Therefore, within the scope of this study, it is considered that A type has a high potential for utilization as a road repair material.

폴리실리콘 슬러지 첨가율에 따른 고화재의 특성

최병철(Choi, Byung Cheol),이상수(Lee, Sang Soo) 한국콘크리트학회 2020 한국콘크리트학회 학술대회 논문집 Vol.32 No.2