• Title/Summary/Keyword: 사용후연료

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Evaluation of Quality Standards of Bio-Diesel (BD100, BD20) Manufactured Using Waste Frying Oil (폐식용유를 이용하여 제조한 바이오디젤(BD100, BD20)의 품질기준 평가)

  • Na, Seong-Joo;Jeon, Byung-Gwan
    • Journal of the Korea Organic Resources Recycling Association
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    • v.17 no.1
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    • pp.39-48
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    • 2009
  • Biodiesel is estimated to be the best recycling energy source as an alternative fuel for transportation vehicles which represents the biggest share of greenhouse effect gas exhausts. Thus, in order to widely expand use of biodiesel and to enhancement its reliability, studies on quality improvement of biodiesel is needed. In this study, we have produced biodiesel(BD100, BD20) through esterification reaction using raw material of waste frying oil and analyzed compatibility with 24 items of quality criteria. As waste frying oil has high contents of unsaturated fatty acid such as Oleic acid, Linoleic acid and Linolenic acid, it is confirmed that there is no problem in using the same as a raw material of biodiesel. The result of analyzing the quality criteria items of biodiesel showed that it satisfied all the quality criteria except the oxidation stability of BD100, which was 2 hours, fatty acid methyl ester of BD20, which was 18.6w% and the filter plugging point, which was $-5^{\circ}C$. We believe that it will contribute to improved utilization of waste resources as alternative energy if studies on technology to improve quality of some items are provided.

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Investigation of Early-Age Concrete Strength Development Using Hardening Accelerator (경화촉진제를 사용한 콘크리트의 초기강도 발현 특성 검토)

  • Kim, Gyu-Yong;Kim, Yong-Ro;Park, Jong-Ho
    • Journal of the Korea Concrete Institute
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    • v.28 no.3
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    • pp.309-316
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    • 2016
  • In this study, performance of hardening accelerator types which promote setting and hardening of cement has been reviewed in order to develop early age strength of concrete with compressive strength of 21~27 MPa after examination of strength development of the concrete at early age according to curing temperature and unit cement(binder) content. As results, soluble mineral salt showed better hardening acceleration effect than organic salt in the scope of this study. Also, hydration reaction accelerating effect of $C_3S$ by Soluble mineral salt is effective on development of early age compressive strength and it was shown that the Pt's hydration reaction accelerating effect was the best. Construction duration reduction can be expected by securing compressive strength for prevention of early aged freezing damage in 25hour-curing time under curing temperature at $15^{\circ}C$. Also, it was shown that compressive strength of specimen cured at $5^{\circ}C$ was similar with plain specimen cured at $10^{\circ}C$. Therefore, it is expected that fuel costs and carbon dioxide can be reduced when the same construction duration is considered.

Development of a Multi-step Stamping Process for the Effective Fabrication of a Thin Sheet for High Aspect Ratio Corrugated Structures (고세장비 연속주름을 갖는 박판구조물 제작을 위한 다단성형공정 개발)

  • Choi, Sung-Woo;Park, Sang-Hu;Jeong, Ho-Seung;Min, June-Kee;Jeong, Jae-Hun;Cho, Jong-Rae;Kim, Hyun-June;Willians, Paul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.2
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    • pp.219-226
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    • 2010
  • The stamping process is widely used in fabricating various sheet-parts for vehicle, airplane, and electronic devices due to its low processing cost and high productivity. Recently the use of thin sheets with corrugated structures has rapidly increased for the production of energy devices, e.g., heat exchangers and fuel cells. However, it is very difficult to make corrugated structures directly in the stamping process due to their geometrical complexity. To solve this problem, this paper proposes a multi-step stamping process with a combined heat treatment process: a sequence of the first stamping, heat treatment, and second stamping. By multi-stamping, we obtained successful results in fabricating very thin corrugated structures with thicknesses of $100{\mu}m$; these are applicable as part of a plate-type heat exchanger.

Cellulosic Ethanol as Renewable Alternative Fuel (신재생 대안 에너지로서의 셀룰로스 에탄올)

  • Cho, Woo-Suk;Chung, Yu-Hee;Kim, Bo-Kyung;Suh, Su-Jeoung;Koh, Wan-Soo;Choe, Sung-Hwa
    • Journal of Plant Biotechnology
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    • v.34 no.2
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    • pp.111-118
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    • 2007
  • Global warming crisis due primarily to continued green house gas emission requires impending change to renewable alternative energy than continuously depending on exhausting fossil fuels. Bioenergy including biodiesel and bioethanol are considered good alternatives because of their renewable and sustainable nature. Bioethanol is currently being produced by using sucrose from sugar beet, grain starches or lignocellulosic biomass as sources of ethanol fermentation. However, grain production requires significant amount of fossil fuel inputs during agricultural practices, which means less competitive in reducing the level of green house gas emission. By contrast, cellulosic bioethanol can use naturally-growing, not-for-food biomass as a source of ethanol fermentation. In this respect, cellulosic ethanol than grain starch ethanol is considered a more appropriate as a alternative renewable energy. However, commercialization of cellulosic ethanol depends heavily on technology development. Processes such as securing enough biomass optimized for economic processing, pretreatment technology for better access of polymer-hydrolyzing enzymes, saccharification of recalcitrant lignocellulosic materials, and simultaneous fermentation of different sugars including 6-carbon glucose as well as 5-carbon xylose or arabinose waits for greater improvement in technologies. Although it seems to be a long way to go until commercialization, it should broadly benefit farmers with novel source of income, environment with greener and reduced level of global warming, and national economy with increased energy security. Mission-oriented strategies for cellulosic ethanol development participated by government funding agency and different disciplines of sciences and technologies should certainly open up a new era of renewable energy.

Fabrication of Electrospun PAN/FA Nanocomposites and Their Adsorption Effects for Reducing Volatile Organic Compounds (전기방사에 의한 PAN/FA 나노 복합재의 제조 및 휘발성 유기 화합물에 대한 흡착효과)

  • Ge, Jun Cong;Wang, Zi Jian;Yoon, Sam Ki;Choi, Nag Jung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.6
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    • pp.702-708
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    • 2018
  • Volatile organic compounds (VOCs), as a significant air pollutant, is generated mainly from the burning of fossil fuels, building materials using painting, etc. The inhalation of a certain amount of VOCs can be deleterious to human health, e.g., headaches, nausea and vomiting. In addition, it can also cause memory loss and even increase the rate of leukemia. Therefore, as one of the methods for reducing VOCs in air, polyacrylonitrile/fly ash (PAN/FA) composite nanofibrous membranes were fabricated by electrospinning. To observe their VOCs adsorption capacity, the morphological structure of PAN/FA nanofibrous mats was investigated by field emission scanning electron microscopy (FE-SEM), and the VOCs (chloroform, benzene, toluene, and xylene) adsorption capacity of PAN/FA membranes were tested by gas chromatography/mass spectrometry (GC/MS). The results indicated that the PAN nanofiber containing 40 wt. % FA powder had the smallest fiber diameter of 283 nm; they also showed the highest VOCs adsorption capacity compared to other composite membranes.

Application of Galvanic Oxidation and Pyrite Dissolution for Sustainable In-Situ Mine Tailings Treatment (갈바닉 산화와 황철석 용해를 이용한 친환경 원위치 광미 무해화 기술)

  • Ju, Won Jung;Jho, Eun Hea;Nam, Kyoungphile
    • Ecology and Resilient Infrastructure
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    • v.3 no.4
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    • pp.279-284
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    • 2016
  • Mine tailings generated during mining activity often contain high concentrations of heavy metals, with pyrite-containing mine tailings in particular being a major cause of environmental problems in mining areas. Chemical cell technology, or fuel cell technology, can be applied to leach heavy metals in pyrite-containing mine tailings. As pyrite dissolves through spontaneous oxidation (i.e. galvanic oxidation) in the anode compartment of the cell, $Fe^{3+}$, sulfuric acid are generated. A decrease in pH due to the generation of sulfuric acid allows heavy metals to be leached from pyrite-containing mine tailings. In this study, pyrite was dissolved for 4 weeks at $23^{\circ}C$ in an acidic solution (pH 2) and in a galvanic reactor, which induces galvanic oxidation, and total Fe leached from pyrite and pH were compared in order to investigate if galvanic oxidation can facilitate pyrite oxidation. The change in the pyrite surface was analyzed using a scanning electron microscope (SEM). Comparing the total Fe leached from the pyrite, there were 2.9 times more dissolution of pyrite in the galvanic reactor than in the acidic solution, and thus pH was lower in the galvanic reactor than in the acidic solution. Through SEM analysis of the pyrite that reacted in the galvanic reactor, linear-shaped cracks were observed on the surface of the pyrite. The study results show that pyrite dissolution was facilitated through the galvanic oxidation in the galvanic reactor, and also implied that the galvanic oxidation can be one remediation option for pyrite-containing mine tailings.

An Evaluation of the Student Performance and Perception of the Food and Nutrition Subject in the Elementary School Curriculum in Incheon, Korea (실과의 식품영양 단원에 관한 교사 학생의 인지 및 학생의 지식, 태도, 기능간의 상관 연구 -인천직할시 공립국민학교를 중심으로-)

  • 김수자
    • Journal of Korean Home Economics Education Association
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    • v.5 no.1
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    • pp.97-111
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    • 1993
  • 본 연구는 국민학교 실과 과목의 식품 영양 단원에 관한 교사, 학생의 인지 및 학생의 지식, 태도, 기능 평가를 위하여 71개 인천시내 공립 국민학교 4,5,6학년 교사 510명과 12개교학생 1,754명을 대상으로 설문조사를 통한 내용을 분석한 것으로 연구의 목적은 1)실과의 정해진 교육목표에 관한 교사의 인지정도 규명 2)식품, 영양 단원에서 교사가 중요하다고 인지하는 내용과 가르치기에 어려움을 느끼는 내용 규명 3)교사가 인지하는 식품영양 단원학습을 증진하기 위한 요소 4) 학생들이 흥미를 느끼는 내용 5)본 단원 학습 후 학생의 지식, 태도, 기능 정도 6)지식, 태도 기능간의 상호 상관관계 규명 등이며 그 연구결과는 다음과 같다. 1. 교사들이 인지하는 실과의 정해진 교육목표는 거의 모두가 중요한 것으로 나타났다. 2. 교사들이 인지하는 식품 영양 단원의 중요한 내용은 영양과 질병과의 관계, 식품위생, 식품저장 등이며, 가장 중요하지 않은 내용으로는 영양 필요량이었다. 또한, 지도에 어려움을 느끼는 내용은 영양 필요량, 조리준비, 식품구성/함유량 등이며 어려움을 느끼지 않는 내용은 영양과 질병과의 관계, 식품위생, 식품저장 등이었다. 3. 교사가 인지하는 단원 학습 증진을 위한 긍정적 요소는 적합한 실습설비와 자료, 시청가자료등이었고 부정적 요소는 남교사, 실험 실습이 필요한 부분은 숙제로 미루는 것 등이었다. 4. 학생들이 흥미를 느끼는 내용으로는 간단한 음식 만들기, 영양소의 기능, 영양문제 등이었고, 쥬스나 차 준비, 조리연료, 부엌용구 사용법 등은 흥미를 느끼지 못하는 내용이었다. 5. 학생의 학업성취 중 지식은 4학년이 식품위생, 기초식품군이, 5학년은 알맞은 조리용구, 조리원리, 6학년은 여가활용의 뜻, 올바른 예절 등이 90% 이상 바르게 답하였고 5학년의 삶은 달걀의 화학적 변화, 감자의 주된 영양 등은 60%이하였다. 6 태도 테스트 결과는 5학년이 4,6학년보다 약간 높은정도(Mn=3.653) 였으나 기능테스트에서는 4학년이 5,6학년보다 약간 낮게 (Mn=3.0) 나타났다(구체적인 것은 본문 참조). 7, 4, 5, 6학년 모두 지식, 태도 기능 간에 정적 상관을 나타내었는데 특히 태도와 기능 사이에는 4학년 r=.7166, 5학년 r=.5175, 6학년 r=.6796을 나타내었고 지시과 태도(4학년 r=.1546, 5학년 r=.0872, 6학년 r=.2192)와 지식과 기능사이에서는 (4학년 r=.1631, 5학년 r=.0585, 6학년 r=.2521)태도와 기능간보다 약한 상관관계를 보였다.

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Extraction Equilibria of Acrylic Acid with Amine Extractants (아민계 추출제에 의한 아크릴산의 추출 평형)

  • Lee, Yong Hwa;Lee, Jun;Hong, Yeon Ki
    • Clean Technology
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    • v.20 no.2
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    • pp.103-107
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    • 2014
  • Acrylic acid is a commodity chemical which is applicable for various industries such as polymer and textile industry. Currently, it has been produced by chemical synthesis from petroleum. However, due to the high price of petroleum and global $CO_2$ emission, renewable materials such as sugar are interesting alternative carbon sources for the biological production of acrylic acid. For an economic production of acrylic acid from renewable carbon sources, a cost effective separation process for acrylic acid should be needed. In this study, reactive extraction by TOA (tri-n-octylamine) was used for the recovery of acrylic acid from its aqueous solutions. The effects of polarity of diluents and concentration of TOA on extraction equilibrium were investigated. The extraction efficiency was proportional to concentration of TOA and polarity of diluents and its value was more than 95% in the case of sufficient concentration of TOA. From IR spectroscopy, it was concluded that the ratio of (1,1) acid-amine complex was increased and the ratio of acid dimer was decreased with concentration of TOA. Equilibrium model based on IR spectroscopy was well fitted with experimental data.

A Study on Launching of New Climate System and Greenhouse Gas Emissions Regulations in China's Ports (신기후체제의 출범과 중국 항만의 온실가스 규제에 관한 연구)

  • Kim, Sung-Kuk;Pak, Myong-Sop
    • Journal of Korea Port Economic Association
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    • v.32 no.2
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    • pp.73-90
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    • 2016
  • In Climate change is a global issue that requires global responses. As a key factor in climate change, greenhouse gas (GHG) emissions have attracted increasing attention the international community. One of the crucial global efforts to alleviate climate change is the establishment of an international climate change regime, comprising rules, norms, principles, procedures that are applicable to a wide range of activities. The International Maritime Organization (IMO) received a mandate from the Kyoto Protocol to regulate shipping GHG emissions. However, the IMO Convention and the UN Convention on the Law of the Sea also provide regulations on regarding GHG emissions. To execute its mandate, the IMO has developed various regulatory initiatives. In addition, the Chinese government has declared new regulations which designate parts of its coastal waters as emission control areas (ECA). Owing to the growing recognition of the benefits of ECA, ships, including ocean-going vessels that operate in areas near the Pearl River Delta, Yangtze River Delta, and the Bohai Sea will be obliged to use fuel containing less than 0.5% sulfur. China's shipping industry is playing a growing role in the international shipping market, and its response to these initiatives will have a substantial effect on the future application of these regulations. This study analyzed the GHG mandates of the IMO and the Chinese government, and then examines the main outcomes that have been achieved.

The Earth-Moon Transfer Trajectory Design and Analysis using Intermediate Loop Orbits (중개궤도를 이용한 지구-달 천이궤적의 설계 및 분석)

  • Song, Young-Joo;Woo, Jin;Park, Sang-Young;Choi, Kyu-Hong;Sim, Eun-Sup
    • Journal of Astronomy and Space Sciences
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    • v.26 no.2
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    • pp.171-186
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    • 2009
  • Various Earth-Moon transfer trajectories are designed and analyzed to prepare the future Korea's Lunar missions. Minimum fuel trajectory solutions are obtained for the departure year of 2017, 2020, 2022, and every required mission phases are analyzed from Earth departure to the final lunar mission orbit. N-body equations of motion are formulated which include the gravitational effect of the Sun, Earth and Moon. In addition, accelerations due to geopotential harmonics, Lunar J2 and solar radiation pressures are considered. Impulsive high thrust is assumed as the main thrusting method of spacecraft with launcher capability of KSLV-2 which is planned to be developed. For the method of injecting a spacecraft into a trans Lunar trajectory, both direct shooting from circular parking orbit and shooting from the multiple elliptical intermediate orbits are adapted, and their design results are compared and analyzed. In addition, spacecraft's visibility from Deajeon ground station are constrained to see how they affect the magnitude of TLI(Trans Lunar Injection) maneuver. The results presented in this paper includes launch opportunities, required optimal maneuver characteristics for each mission phase as well as the trajectory characteristics and numerous related parameters. It is confirmed that the final mass of Korean lunar explorer strongly depends onto the initial parking orbit's altitude and launcher's capability, rather than mission start time.