• 한국치위생학회지
• /
• 제15권2호
• /
• pp.319-324
• /
• 2015

Objectives: The purpose of this study was to verify the oral environmental change in using the natural oral cleaner containing propolis and prevention effect of oral disease. Methods: The subjects were 60 university students in Gangwon province. The groups consisted of 30 students of experimental group and 30 students of control group. The subjects were those who did not take the antipsychotic, diuretic, antihistamine, and anesthetic. The students rinsed their mouth with propolis mixture of oral cleanser for 4 weeks after receiving informed consent from October 1 to November 2, 2012. Collected saliva was measured for amount, salivary consistency, pH, plague index, gingival index, and halitosis. Results: The amount of salivary in propolis mixture of oral cleansing group remarkably increased (t=2.16, p<0.05). pH was alkaline in the group with oral cleaner containing the propolis (t=2.80, p<0.01). The bad breath remarkably decreased in the group with oral cleaner containing the propolis (t=-5.77, p<0.001). Conclusions: The use of the oral cleaner containing the propolis increased the amount of salivary and pH. The use of oral cleaner containing the propolis reduces halitosis and maintains good quality of oral hygiene.

• 한국연초학회지
• /
• 제20권1호
• /
• pp.124-130
• /
• 1998

This study was conducted to evaluate the ability of anion generating air cleaner to remove gases, vapor and particles from closed room contaminated with environmental tobacco smoke (ETS). The measurements covered particle sizes of 13.8-542.5nm, particle concentration, surface area, volumes UVPM, FPM, solanesol, and the following gases and vapor; carbon dioxide, carbon monoxide, nicotine, and 3-ethenylpyridine. Tobacco smoke was generated and mixed in a closed room in which the airflow rates were in the range of 0.00-0.04 m/s. The anion generating air cleaner was startedl and the decay rates for the gases, vapor and particles were measured, When the use of anion generating air cleaner, solid components of ETS, such as respirable suspended particle (RSP), utraviolet particulate matter (UVPM, fluorescent particulate matter (FPM) and solanesol was sharply decreased, and vapor phase components of ETS, such as nicotines 3-ethenylpyidine were modelately decreased by time elapse. Even the use of anion generation air cleaner, the decreasing rate of carbon dioxide concentration was similar with control, and the decreasing rate of carbon monoxide was slower than that of control. Our results indicated that the use of anion generting air cleaner had an effect on reduction of solid and vapor components from ETs, but it had no effect on gaseous components of ETS.

• 청정기술
• /
• 제9권3호
• /
• pp.107-113
• /
• 2003

인쇄 및 출판 산업의 발전으로 인쇄공정에서는 다량의 유독성 폐기물 및 폐수등이 발생한다. 인쇄공정에서 필수적으로 사용되는 각종 환경오염물질에 대한 규제가 강화되고 있기에 환경친화형 청정기술 개발이 필요하며 또한 인쇄업계의 적극적인 환경대응책이 필요한 시점이다. 따라서 본 연구에서는 인쇄폐수에 대한 정밀여과, 한외여과, 역삼투 등의 막분리 시스템의 효용성을 검토하고 공정을 개선할 수 있는 기본 자료를 도출하여 처리수의 재이용 방안을 모색하고 공정의 최적화를 도모하고자 하였다. 그 결과 U/F System의 운전압력은 $2kg/cm^2$이 적당하였으며, U/F처리수는 탁도 3NTU 이하로서 인쇄공정 현장에서 기계세척수로 사용가능할 것으로 판단되었다.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1997년도 전력전자학술대회 논문집
• /
• pp.193-199
• /
• 1997

Until now, environmental problem has become more and more serious, and acoustic noise is one of environmental pollutions. For many years, ANC(Active Noise Control) has been made to reduce this noise. In this paper, active silencer using switching method is studied. This silencer is composed of single-phase full bridge inverter to drive cancelling loudspeaker. The inverter is controlled to reduce noise by ramp comparison control method. At the vacuum cleaner, noise control with FFCS(Feed-Forward Control Structure) is applied and geometric arrangement is replaced to avoid unstability of FFCS.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2001년도 춘계학술대회 발표논문집
• /
• pp.290-291
• /
• 2001

The relationship between velocity, viscosity, diffusion coefficient, mass transfer coefficient and characteristic length and mass transfer data can be correlated by dimensionless relationship in electrolytic process. The performance of dyestuff removal was decreased as the flow rate of electrolyte was increased. It was due to the effect of retention time decreasing was superior to that of turbulent inlet mixing. Sh/Sc$\^$1/3/ vs Re plot for Al flat electrode did not showed the general tendency of the relationship between Sh/Sc$\^$1/3/ and Re. It can be thought that flow rate was not sufficiently high to increase the effect of mixing.

• 품질경영학회지
• /
• 제27권3호
• /
• pp.170-188
• /
• 1999

In all activities of companies, manufacturing processes are one of those which have the worst effect on our environment. So manufacturing companies have taken the necessary steps to comply with environmental regulations. But, most of them focused on the environmental standard control equipments, using ‘end-of-pipe techniques’ that can obtain the desired reductions in a short time-period. But these methods are essentially symptomatic treatments and are not enough for sustainable development. 3M's solution is the ‘cleaner techniques’which emphasize prevention rather than corrective control. This paper examines the concept of cleaner techniques and the environmental management system of 3M - how to conduct technological innovation to prevent generation of pollution and waste at the source under the 3P program.

• 대한환경공학회지
• /
• 제31권3호
• /
• pp.163-172
• /
• 2009

• Journal of Microbiology and Biotechnology
• /
• 제17권10호
• /
• pp.1622-1628
• /
• 2007

We characterized the efficacy of an electrostatic precipitator (ESP) air-cleaner in reducing the concentration of Serratia marcescens in an enclosed space. We used an experimental room ($4.5{\times}3{\times}2.9\;m$) in which electrostatic air-cleaners were located. Two air-cleaners enhanced the equivalent ventilation rates in the chamber by about 3.3 air changes per hour (ACH) over the 2 ACH provided by the mechanical ventilation system. Natural die-off of the organisms provided an additional equivalent of 3 ACH, so that the total ventilation rate with the ESP air-ccleaners was 8.3 ACH. We also examined whether the ESP air-cleaners altered the deposition of Serratia marcescens aerosols on the experimental room surfaces. We did not find any significant differences in the number of colony forming units recovered from surfaces with and without the air-cleaners. We installed UV lights inside the ESPs and determined if UV light, in addition to electrical fields, increased the efficacy of the ESPs. The presence of UV light inside the ESP reduced S. marcescens aerosols by approximately 2 ACH. Finally, a box model indicates that the efficiency of the air-cleaner increases for both biological and nonbiological particles at ventilation rates of 0.2-1, which are typical for residential settings.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.1757-1763
• /
• 2011

In recent years, accordance to industrial development project on railway investment, adverse environmental issues of the investment, such as disputed cases about recycling and usage of Ballast Cleaner excavated soil, have been continuously increasing. It will not only enhance the regulation of soil contamination but take considerable time and cost in future. In this study, we investigated soil contamination and burnability with soil of Chungang Line, Taebaek Line, Chungbuk Line, in order to seize a possibility of recycling Ballast Cleaner excavated soil for the natural materials and substantial heat sources, which are necessary resources for cement manufacturing process. As a result of this study, It is found that Ballast Cleaner excavated soil is satisfied with a standard. The excavated soil contains a lot of cement ingredients and fossil fuel dust incurred from freight transportation, so it is expected to use for ingredients of cement and replacement of heat sources.

• 청정기술
• /
• 제5권1호
• /
• pp.62-77
• /
• 1999

전자 및 컴퓨터 산업의 발전으로 반도체 산업은 비약적으로 발전하고 있다. 그러나 반도체 제조 공정에서 필수적으로 사용되는 각종 환경 오염 물질에 대한 규제가 세계적으로 강화되고 있어 반도체 업계의 적극적인 환경 대응책이 없이는 반도체 수출에 대한 선진국의 제재를 피하기 어렵다. 따라서 본 연구에서는 청정 기술 측면에서, 반도체 산업의 환경영향 개선을 위한 세정 공정의 기술적 대체 방안에 대하여 조사하였다. 세정 공정의 대안으로서 기상 세정 공정, UV 사용 공정, 플라즈마 사용 공정을 조사하였으며, 각 공정의 장단점을 비교하였다.