• 한국도로학회논문집
• /
• 제19권2호
• /
• pp.75-85
• /
• 2017

PURPOSES : The purpose of this study was to determine the optimum mix design of the content of 100 % reclaimed asphalt pavement (RAP) for spray injection application with different binder types. METHODS : Literature review revealed that spray injection method is the one of the efficient and economical methods for repairing a small defective area on an asphalt pavement. The Rapid-Setting Polymer modified asphalt mixtures using two types of rapid setting polymers-asphalt emulsion and a quick setting polymer asphalt emulsion-were subjected to the following tests to determine optimum mix designs and for performance comparison: 1) Marshall stability test, 2) Retained stability test, 3) Wet track abrasion test, and 4) Dynamic stability test. RESULTS and CONCLUSIONS : Type A, B, and C emulsions were tested with different mix designs using RAP aggregates, to compare the performances and determine the optimum mix design. Performance of mixtures with Type A emulsion exceeded that of mixtures with Type B and C emulsion in all aspects. In particular, Type A binder demonstrated the highest performance for WTAT at low temperature. It demonstrated the practicality of using Type A mixture during the cold season. Furthers studies are to be performed to verify the optimum mix design for machine application. Differences in optimum mix designs for machine application and lab application will be corrected through field tests.

• Asian-Australasian Journal of Animal Sciences
• /
• 제29권8호
• /
• pp.1102-1110
• /
• 2016

The mammalian target of rapamycin (mTOR) regulates cellular processes such as cell growth, metabolism, transcription, translation, and autophagy. Rapamycin is a selective inhibitor of mTOR, and induces autophagy in various systems. Autophagy contributes to clearance and recycling of macromolecules and organelles in response to stress. We previously reported that vitrified-warmed mouse oocytes show acute increases in autophagy during warming, and suggested that it is a natural response to cold stress. In this follow-up study, we examined whether the modulation of autophagy influences survival, fertilization, and developmental rates of vitrified-warmed mouse oocytes. We used rapamycin to enhance autophagy in metaphase II (MII) oocytes before and after vitrification. The oocytes were then subjected to in vitro fertilization (IVF). The fertilization and developmental rates of vitrified-warmed oocytes after rapamycin treatment were significantly lower than those for control groups. Modulation of autophagy with rapamycin treatment shows that rapamycin-induced autophagy exerts a negative influence on fertilization and development of vitrified-warmed oocytes.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2006년도 전력전자학술대회 논문집
• /
• pp.206-209
• /
• 2006

At present, the cold cathode fluorescent lamp (CCFL) using mercury lamp has been generally used far liquid crystal backlight source of personal computer and car navigation and so on. This kind of lamp is more excellent on luminance performance and cost. However, the requirements of liquid crystal backlight due to a light source without mercury have been strongly increased from a viewpoint of the actual influence on environmental preservation and environmental recycling. As fluorescent lamp without mercury, Dielectric Barrier Discharge based rare gas fluorescent lamp (DBD-FL) using xenon (Xe) gas has been studied so far. This DBD lamp has no influence on the human body and environmental recycle. Its operating life is long because electrode is out. In this paper, the simulation and experimental results of soft switching high frequency inverter with reverse blocking single switch as a high frequency power supply circuit for DBD-FL using Xe gas are comparatively evaluated and discussed from a practical point of view.

• 대한환경공학회지
• /
• 제35권5호
• /
• pp.350-355
• /
• 2013

본 연구는 음료용 자동판매기의 냉매인 HFC-134a의 사용 및 폐기단계 탈루배출특성을 파악코자 하는데 그 목적을 두고 있다. 국내 제품인 음료용 폐자동판매기 47대의 HFC-134a 냉매를 상업용 냉매 회수기를 사용 회수하였고, 잔류량을 측정하였다. 본 연구에서 개발한 사용단계 탈루배출모델은 1차 동역학에 기초한 것으로 탈루율은 잔류 냉매 압력 즉 잔류량에 비례한다는 가정을 도입 적용하였다. 음료용 폐자동판매기의 배출시점에서의 잔류량과 사용기간 정보를 활용하여 탈루배출계수를 간접적으로 $6.9{\pm}0.7$ %/yr으로 결정하였고 이는 1대당 연간 11.6 g의 HFC-134a가 배출되는 것에 해당된다. 한편 음료용 폐자동판매기 냉매 평균 잔류율은 $62.5{\pm}2.2%$이었으며, 이는 1대당 잠재 탈루량을 144.8 g으로 결정할 수 있다. 음료용 자동판매기에서 회수한 폐냉매 성분 분석 결과가 신냉매와 거의 유사하여 폐냉매의 재사용이 가능할 것으로 여겨진다. 그러나 냉매회수 과정에서 압축기 오일이 30% 정도 포함되기 때문에 냉매 재사용을 위해서는 오일 분리가 필요하다.

• 환경위생공학
• /
• 제7권2호
• /
• pp.1-10
• /
• 1992

Since 1960's along with industrialization and urbanization, economic growth has been . achieved, however, at the same time, environmental condition has been seriously deteriorated. . Currently, volume of wastewater has been increasing at annual rate of 7% in sewage and 20% in industrial wastewater. However, the nation's sewage treatment serves only 33% of the municipal wastewater as of 1991. Major portion of air pollutants comes from combustion of oil and coal which comprise 81% of total energy use and emission gases from motor vehicles increasing at an accelerated rate. It is known that Korea generates the highest amount of waste per capta. Nevertheless, it is not sufficient to reduce the volume of waste by means of resources recovery and recycling. Recognizing the importance of global environmental problems such as ozone layer depletion, global warming and acid rain, international society has been making various efforts since the 1972 Stockholm conference. In particular, it is expected that the Rio conference which has adopted the Rio declaration and Agenda 21 will form a crucial turning point of the emerging new world order after the Cold War confrontation. To cope with such issues as domestic pollution and global environmental problems, the fundamental national policy aims at harmonizing "environmental protection and sustainable development". The Ministry of Environment has recently set up a mid-term comprehensive plan which includes annual targets for environmental protection. According to the government plan, gradual improvement of various environmental conditions and specific measures to achieve them is planned in time frame. Additional sewage treatment plants will be constructed in urban areas with the target to treat 65% of the nation's municipal sewage by 1996. Supply of clean fuels such as LNG will also be expanded starting from large cities as a cleaner substitute energy for coal and oil. In parallel with expansion of LNG, emphasis will be placed on installation of stack monitoring system. Due to the relatively limited land, government's basic policy for solid waste treatment is to develop large scale landfill facilities rather than small sized ones. Thirty three regional areas have been designated for the purpose of waste management. For each of these regions, big scale landfill site is going to be developed. To increase the rate of waste recycling the government is planning to reinforce separate collection system and to provide industries with economic incentives. As a part of meeting the changing situation on global environmental problems after UNCED, and accommodation regulatory measures stipulated in the global environmental conventions and protocols, national policy will try to alter industrial and economic structure so as to mitigate the increasing trends of energy consumption, by encouraging energy conservation and efficiency. In this regard, more attention will be given to the policy on the development of the cleaner technology. Ultimately, these policies and programs will contribute greatly to improving the current state of national public health.

• 유기물자원화
• /
• 제8권4호
• /
• pp.138-146
• /
• 2000

본 연구는 일반 단독주택 등의 가정에서 쉽게 사용할 수 있는 최상의 발효토를 도출하고자 직접 음식물쓰레기 소멸실험을 행하였다. 실험 결과, 반응기 내 미생물의 활성에 의해 음식물쓰레기를 투입한 직후의 초기에 비해 다음 음식물쓰레기 투입직전인 9일 후의 온도, 무게, 함수율, vs의 값이 감소하였고, 모든 반응기에서 소멸화는 진행되었다. 그 중에서도 S대 미생물제재를 발효토로 사용한 반응기인 F, 4번 반응기가 가장 좋은 결과를 보였으며, 음식물의 투입주기를 단축하는 것이 가능하였다. 반응이 양호하지 않은 반응기는 시간이 지날수록 그 무게와 수분이 증가하여 장기간 반응 시 악영향을 미칠 것으로 판단된다. 염분은 시간이 지날수록 소멸되지 않고 축적되었다. 성능이 우수했던 S대 발효토를 이용한 적용가 온도에 크게 영향을 받았다. 그러나 반응기간은 S대 미생물을 고정한 발효토를 이용한 반응기를 $20^{\circ}C$에서 유지하였을 때 3일 정도로 처리기간을 단축 시킬수 있었다.

• 한국에너지공학회:학술대회논문집
• /
• 한국에너지공학회 2002년도 춘계 학술발표회 논문집
• /
• pp.227-234
• /
• 2002

With the increasing environmental consideration and stricter regulations, gasification of waste is considered to be more attractive technology than conventional incineration for energy recovery as well as material recycling. The experiment for combustible waste mixed with plastic and cellulosic materials was performed in the fixed bed gasifier to investigate the gasification behavior with the operating conditions. Waste pelletized with a diameter of 2~3cm and 5cm of length was gasified at the temperature range of 1100~145$0^{\circ}C$. It was shown that the composition of H$_2$ was in the range of 30~40% and CO 15~30% depending upon oxygen/waste ratio. Casification of waste due to thermoplastic property from mixed plastic melting and thermal cracking shows a prominent difference from that of coal or coke. It was desirable to maintain the top temperature up to foot to ensure the mass transfer and uniform reaction through the packed bed. As the bed height was increased, the formation of H$_2$ and CO was increased whilst $CO_2$ decreased by the char-$CO_2$ reaction and plastic cracking. From the experimental results, the cold gas efficiency was around 61% and heating values of product gases were in the range of 2800~3200㎉/Nm3.

• 한국도로학회논문집
• /
• 제20권1호
• /
• pp.77-85
• /
• 2018

PURPOSES : The purpose of this study was to develop an urgent road-repair system and perform a field applicability test, as well as discover the optimum mix design for machine applications compared to the optimum mix design for lab applications. METHODS : According to reviews of the patent and developed equipment, self-propelled and mix-in-place equipment types are suitable for urgent pavement repair, e.g., potholes and cracks. The machine-application mix design was revised based on the optimum lab-test mix design, and the field application of a spray-injection system was performed on the job site. The mixture from the machine application and lab application was subjected to a wet-track abrasion test and a wheel-tracking test to calibrate the machine application. RESULTS and CONCLUSIONS : This study showed that the binder content could differ for the lab application and the machine application in the same setting. Based on the wet-track abrasion test result, the binder contents of the machine application exceeded the binder contents of the lab application by 1-1.5% on the same setting value. Moreover, the maximum dynamic stability value for the machine application showed 1% lower binder contents than the maximum lab-application value. Collectively, the results of the two different tests showed that the different sizes and operating methods of the machine and lab applications could affect the mix designs. Further studies will be performed to verify the bonding strength and monitor the field application.

• 한국도로학회논문집
• /
• 제18권2호
• /
• pp.61-71
• /
• 2016

PURPOSES: The objective of this study was to determine the optimum ratio of mix design, for a reclaimed asphalt pavement (RAP) content of 100%, for spray injection application. METHODS: A literature review revealed that spray injection is an efficient and cost-effective application for fixing small defective regions of an asphalt pavement. Rapid-setting polymer-modified asphalt mixtures prepared from two types of rapid-setting polymer asphalt emulsion were subjected to Marshall stability and wet track abrasion tests, in order to identify the optimum mix designs. RESULTS and CONCLUSIONS : Different mix designs of type A and type B emulsions were prepared using RAP and virgin aggregates, in order to compare the performance and determine the optimum mix design. The performance of mixtures prepared with RAP was superior to that of mixtures containing virgin aggregates. Moreover, for optimum ratio of the design, the binder content prepared from RAP was set to 1~2% lower than that consisting of virgin aggregates. Compared to their Type A counterparts, type B mixtures consisting of a reactive emulsion performed better in the Marshall stability and wet track abrasion tests. The initial results confirmed the advantages associated with using RAP for spray injection applications. Further studies will be performed to verify the difference in the optimum mix design and performance obtained in the lab-scale test and tests conducted at the job site by using the spray injection machine.

• 한국태양에너지학회 논문집
• /
• 제28권4호
• /
• pp.10-16
• /
• 2008

The fire resistance of thermal insulation and interior finishing materials is recently much emphasized after the fire accident at the Icheon Cold Store in January 2008. Three kinds of thermal insulation are used in buildings. They are Organic, Non-organic and cellulosic insulation. Organic insulation such as polystyrene foam board and urethane foam has high thermal resistance but it has no fire resistance. While non-organic insulation such as rockwool and glassfiber has high fire resistance, it has lower thermal resistance than organic insulation. Cellulose insulation is primarily manufactured from recycled newsprint or cardboard using shredders and fiberizers. Despite of its environmental friendliness and high thermal resistivity, its domestic use has not much increased because of the prejudice that paper can easily burn. However, the cellulose insulation as a product is about 80 wt.% cellulosic fiber and 20 wt.% chemicals, most of which are fire retardants such as boric acid and ammonium sulfate. It is required to secure its fire safety for more consumption as a building insulation in Korea. Therefore, this study investigates the fire resistance of Korean cellulose insulation according to the rate of fire retardant and finally presents the optimum rate of fire retardant in cellulose as building insulation. The fire safety test was conducted according to the ASTM C 1485-00. The test results indicate that above 18 wt% of fire retardant is necessary to secure the fire safety of cellulose insulation.