• Title/Summary/Keyword: Alternative energy source

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Bioenergy Crop Production and Research Trends (바이오에너지 원료작물 생산 및 연구동향)

  • Kim, Kwang-Soo;Kim, Young-Bum;Jang, Young-Seok;Bang, Jin-Ki
    • Journal of Plant Biotechnology
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    • v.34 no.2
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    • pp.103-109
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    • 2007
  • The increasing industrialization of the world has led to precipitous rise for the demand of petroleum-based fuels. The world is presently confronted with the twin crises of fossil fuel depletion and environmental pollution. The search for alternative fuels, which promise a harmonious correlation with sustainable development, energy conservation, efficiency and environmental preservation, has become highly pronounced in the present. Bioenergy is playing an increasingly important role as an alternative and renewable source of energy. Use of Bioenergy has several potential environmental advantages. The most important perhaps is reduction in life cycle greenhouse gases emissions relatives petroleum fuels, since bioenergy is derived from plants which convert Carbon dioxide ($CO_{2}$) into Carbohydrates in their growth. Bioenergy includes solid biomass, biomas and liquid bio-fuels which are fuels derived from crop plants, and include biomass that's directly burned. The two most important bio liquid fuels today are bioethanol from fermenting grain, grass, straw or wood, and biodiesel from plant seed oil.

Characterization and Early Age Physical Properties of Ambient Cured Geopolymer Mortar Based on Class C Fly Ash

  • Kotwal, Ashley Russell;Kim, Yoo Jae;Hu, Jiong;Sriraman, Vedaraman
    • International Journal of Concrete Structures and Materials
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    • v.9 no.1
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    • pp.35-43
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    • 2015
  • The critical element for sustainable growth in the construction industry is the development of alternative cements. A new technological process called geopolymerization provides an innovative solution, and the presence of aluminum and silicon oxides in fly ash has encouraged its use as a source material. Many previous investigations have involved curing the binder in a heated environment. To reduce energy consumption during the synthesis of geopolymers, the present study investigated the properties of ambient cured geopolymer mortar at early ages. An experimental program was executed to establish a relationship between the activator composition and the properties of geopolymer mortar in fresh and hardened states. Concentrations of sodium hydroxide and sodium silicate were ascertained that are advantageous for constructability and mechanical behavior. Scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction techniques were also used to characterize the material. Test results indicate that there is potential for the concrete industry to use fly ash based geopolymer as an alternative to portland cement.

An Experimental Study on the Leakage Characteristics and Durability Evaluation of an LPLi Injector (LPLi 인젝터의 누설특성 및 내구평가에 관한 실험적 연구)

  • Choi, Young;Kim, Chang-Up;Oh, Seung-Mook;Kang, Kern-Yong
    • Journal of ILASS-Korea
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    • v.12 no.4
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    • pp.204-210
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    • 2007
  • The worldwide energy problem and global warming cause the need of alternative fuels which feature low carbon-dioxide emission and another energy source. Liquefied Petroleum Gas (LPG) is one of the alternative fuels widely used as domestic and transportational fuel. The third generation LPLi fuel supply system has merits in the increase of engine power and low emissions. The injectors used in LPLi system should overcome a leakage problem and satisfy the durability conditions. Therefore, 1000 hour durability test of the injectors was carried out throughout this research. First, the spray pattern and the penetration length of the selected injectors is graphically shown. Next, the leakage amount with respect to the injection cycle is introduced. Finally, the shapes of nozzle holder and nozzle tip after durability test was investigated by analyzing the microscopic image of the injector tip. The variation in the shape of nozzle tip mainly due to the residue of rubber materials is found to be the reason for leakage.

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Verification of Underwater Blasting Response Analysis of Air Gun Using FSI Analysis Technique (FSI 해석기법을 이용한 에어건 수중발파 응답해석 검증)

  • Lee, Sang-Gab;Lee, Jae-Seok;Park, Ji-Hoon;Jung, Tae-Young;Lee, Hwan-Soo;Park, Kyung-Hoon
    • Journal of the Society of Naval Architects of Korea
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    • v.54 no.6
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    • pp.522-529
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    • 2017
  • Air gun shock system is used as an alternative energy source as part of the attempt to overcome the restrictions of economical expense and environmental damage, etc., due to the use of explosives for the UNDerwater EXplosion (UNDEX) shock test. The objectivity of this study is to develop the simulation technique of air gun shock test for the design of model-scale one for the near field non-explosive UNDEX test through its verification with full-scale SERCEL shock test result. Underwater blasting response analysis of full-scale air gun shock test was carried out using highly advanced M&S (Modeling & Simulation) system of FSI (Fluid-Structure Interaction) analysis technique of LS-DYNA code, and was verified by comparing its shock characteristics and behaviors with the results of air gun shock test.

Comparison of Bioethanol Production by Candida molischiana and Saccharomyces cerevisiae from Glucose, Cellobiose, and Cellulose

  • Zheng, Jianning;Negi, Abhishek;Khomlaem, Chanin;Kim, Beom Soo
    • Journal of Microbiology and Biotechnology
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    • v.29 no.6
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    • pp.905-912
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    • 2019
  • Bioethanol has attracted much attention in recent decades as a sustainable and environmentally friendly alternative energy source. In this study, we compared the production of bioethanol by Candida molischiana and Saccharomyces cerevisiae at different initial concentrations of cellobiose and glucose. The results showed that C. molischiana can utilize both glucose and cellobiose, whereas S. cerevisiae can only utilize glucose. The ethanol yields were 43-51% from different initial concentrations of carbon source. In addition, different concentrations of microcrystalline cellulose (Avicel) were directly converted to ethanol by a combination of Trichoderma reesei and two yeasts. Cellulose was first hydrolyzed by a fully enzymatic saccharification process using T. reesei cellulases, and the reducing sugars and glucose produced during the process were further used as carbon source for bioethanol production by C. molischiana or S. cerevisiae. Sequential culture of T. reesei and two yeasts revealed that C. molischiana was more efficient for bioconversion of sugars to ethanol than S. cerevisiae. When 20 g/l Avicel was used as a carbon source, the maximum reducing sugar, glucose, and ethanol yields were 42%, 26%, and 20%, respectively. The maximum concentrations of reducing sugar, glucose, and ethanol were 10.9, 8.57, and 5.95 g/l, respectively, at 120 h by the combination of T. reesei and C. molischiana from 50 g/l Avicel.

Tracking System for Optimum Solar Power System of Widely Separated Cave (고립원격지 동굴 전원용 태양광발전 광 추적 시스템)

  • Suh, Oh-Ji;Soh, Dea-Wha
    • Journal of the Speleological Society of Korea
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    • no.89
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    • pp.27-33
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    • 2008
  • Solar energy is most green and clean, unlimited and sustainable energy source on the earth. It is almost 97% of imported consumer energy in Korea. Because of resource poor nation, it is necessary to do their best to make alternative energy to allot their deficiency of the matter in hand of energy resources of petroleum. In a point of view of this problems, the natural solar energy should be improved by any methods as much, possible as we need. Photovoltaic generation with solar tracking system for obtaining optimal power is one of most benefit equipment to improve power of solar-cell panel producing clean electric power efficiently. Solar tracker is a device for orienting a solar photovoltaic panel toward the sun perpendicularly to sunlight, especially in widely separated place. For this reason, we are very interested in developing the equipment system of tracker, specially in solar cell applications, obtaining a high degree of accuracy to ensure that the optimal sunlight could be directed precisely against to the powered device. As a result, it was obtained of 12.46 volts at 90$^\circ$toward solar panel and 9.44 volts at 45$^\circ$, furthermore, improved efficiency more than 30% of average output voltage between tracker system (12.41V) and fixed system (8.55V), respectively. It is also very useful for optimum power system of widely separated cave.

Current Research Trends in Microbial Fuel Cell Based on Polymer Electrolyte Membranes (고분자 전해질 분리막 기반 미생물 연료전지의 최근 연구동향)

  • Choi, Tae-Hwan;Kim, Hyo-Won;Park, Ho-Bum
    • Membrane Journal
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    • v.20 no.3
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    • pp.173-184
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    • 2010
  • Microbial fuel cell (MFC) is a promising renewable energy source that can generate electrical energy from organic wastes using microbe. This technology has been regarded as a future green alternative energy in that MFC makes use of organic-rich wastewater and also reduces waste sludges as well as produces electricity. To be practically realized, however, achieving higher power density than now is demanded, which may be possible by eliminating various negative factors to act as resistances in MFC operations. For instance, highly activated microbes, highly conductive electrode materials, and fast electron transfer between microbes and electrodes can lead to MFC with high power density. In particular, polymer electrolyte membranes are also a key component for improved MFC performance.

Monte Carlo approach for calculation of mass energy absorption coefficients of some amino acids

  • Bozkurt, Ahmet;Sengul, Aycan
    • Nuclear Engineering and Technology
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    • v.53 no.9
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    • pp.3044-3050
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    • 2021
  • This study offers a Monte Carlo alternative for computing mass energy absorption coefficients of any material through calculation of photon energy deposited per mass of the sample and the energy flux obtained inside a sample volume. This approach is applied in this study to evaluate mass energy absorption coefficients of some amino acids found in human body at twenty-eight different photon energies between 10 keV and 20 MeV. The simulations involved a pencil beam source modeled to emit a parallel beam of mono-energetic photons toward a 1 mean free path thick sample of rectangular parallelepiped geometry. All the components in the problem geometry were surrounded by a 100 cm vacuum sphere to avoid any interactions in materials other than the absorber itself. The results computed using the Monte Carlo radiation transport packages MCNP6.2 and GAMOS5.1 were checked against the theoretical values available from the tables of XMUDAT database. These comparisons indicate very good agreement and support the conclusion that Monte Carlo technique utilized in this fashion may be used as a computational tool for determining the mass energy absorption coefficients of any material whose data are not available in the literature.

A Study on the Pro-Environmental Energy Supply Program of Urban Enterprises on the concept of BAT(Best Available Technology): Application of Air Environmental Indices and Benefit-Cost Analysis Based (한 도시 사업체 에너지 수급의 최적화 방안 연구 - 대기오염지수와 경제성 평가를 중심으로 -)

  • Kwon, Yong-Sik;Kim, Yong-Bum;Chung, Yong
    • Journal of Environmental Impact Assessment
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    • v.7 no.2
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    • pp.89-102
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    • 1998
  • The purpose of this study is to seek AEI(Air Environmental Indices), PSI(Pollutant Standard Index) and the urban air quality control goal(the best available alternative energy program) by assessing the best ratio of energy types used in urban enterprises, based on harmful health effect and air quality standard and costs. This study is focused on an urban area(Puchun), where area sourcees are associated with heavy traffic, large population, and its industrial sources with large emissions. In the first step, air modeling, estimation of AEI and PSI, and benefit-cost analysis were carried out. In the second step, we assessed that 660 scenarios about the ratio of B-C oil, light oil and LNG used in urban enterprises with regard to air quality and cost. In the third step, the best available alternative energy program was selected for the ratio of energy species(B-C oil, light oil and LNG) by using the lexicographic method. From the emission analysis, main source of $NO_2$ is identified as industries and air quality is evaluated according to the ratio of B-C oil, light oil and LNG used in urban enterprise. The modeling data of TSP, $SO_2$, $NO_2$, CO, $O_3$, by ISC3 and PBM are respectively $118{\mu}g/m^3$, 0.027ppm, 0.025ppm, 2.0ppm, 0.55ppm in indurstrial area. That data are close to Environmental Air Quality Standard. By means of sensitivity analysis, we obtained the difference in concentration between the areas(Nae-dong, Joong-dong) according to the ratio of B-C oil, light oil and LNG used in the industries. From the result of alternatives assessment the lowest AEI value and cost, the ratio of B-C oil, light oil and LNG are 2.5%, 20%, 77.5%, respectively.

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The Status of Biogas as Renewable Energy (신재생에너지로서 바이오가스 현황)

  • Lim, Young-Kwan;Lee, Joung-Min;Jung, Choong-Sub
    • Applied Chemistry for Engineering
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    • v.23 no.2
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    • pp.125-130
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    • 2012
  • In these days, there has been increased focus on global warming and the exhaustion of resources recently caused by the heavy consumption of fossil resources. In order to resolve these problems, biomass is increasingly gaining international attention as a renewable energy source. Biogas derived from various biomass is environmental friendly alternative fuel for power generation, heating and vehicle fuel. Large amounts of sewage sludge, food waste and manure are generated from human activity, but these organic wastes contain high levels of organic matter and thus they are potential substrates for producing methane of biogas. The biogas contains 60% of highly concentrated methane, which is expected to be used effectively as energy. In this paper, we investigate the status of biogas in Korea as an alternative energy.