• 제목/요약/키워드: Energy yield

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Economic Effect of Regulation in Logistics/Transport Industry (물류운송산업 규제의 경제적 효과)

  • KIM, Jungwook;WI, Suhyeon
    • Journal of Korean Society of Transportation
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    • v.35 no.3
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    • pp.169-182
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    • 2017
  • This research reviews regulations on logistics/transport industry and attempts to quantify the effects of regulation mitigation on GDP per capita. South Korea's transport industry has been gradually expanding, however, the industrial structure is still short rooted. In 2014, average number of hours worked is 5th highest and wage margin 12th smallest out of 18 industries. Furthermore, the regulations for this industry appear to be stricter than those of other industries. OECD's logistics/transport industry regulatory index for South Korea has been decreasing for the last 40 years but still exceeds those of EU, Japan, US, and other countries. This paper provides supporting reasons for regulatory reforms by analyzing the ripple effects on real GDP. Factors such as the ratio of trade among GDP, the enrollment rate to primary school, energy usage per capita, and population are controlled in the fixed-effect model. Estimation results showed that 1 unit decrease in transport/logistics regulatory index is correlated with 8.1% increase of the real GDP per capita, that is, 10% of deregulation is expected to yield 2.16% increase in GDP per capita. Thus, it is expected that mitigating regulations on market entries, price determination, ownership structures of network industry, vertical integrations can improve the economy of South Korea.

Preparation and Characterization of Nylon 6,5 Copolymers from ε-Caprolactam and 2-Piperidone (ε-Caprolactam과 2-Piperidone으로부터 나일론 6,5 공중합체 제조 및 특성평가)

  • Kim, Hye Young;Goh, Jin-Seon;Ryu, Mi Hee;Kim, Dae Su;Song, Bong-Keun;Lee, Seung Hwan;Park, Si-Jae;Jegal, Jonggeon
    • Polymer(Korea)
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    • v.38 no.1
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    • pp.31-37
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    • 2014
  • To prepare biomass based nylon 6,5 copolymers, ${\varepsilon}$-caprolactam and 2-piperidone, the monomers of nylon 6,5 copolymers, were synthesized respectively from lysine and 5-aminovaleric acid which were produced from glucose by the fermentation process. The copolymers were then polymerized by the anionic ring opening polymerization of them at $40^{\circ}C$, using potassium tert-butoxide as a catalyst and acetyl-2-caprolactam and carbon dioxide as initiators. The prepared copolymers were characterized with various analytical methods: their viscosity molecular weight ($M_{\eta}$) was as high as 30000 g/mol and polymerization yield was over 50%, and it was found that they were semi-crystalline polymers having melting point at $165^{\circ}C$ which was much lower than its thermal degradation point, $250^{\circ}C$. These polymers were expected to have good thermal processability and application fields.

A Study on the Monitoring System of Growing Environment Department for Smart Farm (Smart 농업을 위한 근권환경부 모니터링 시스템 연구)

  • Jeong, Jin-Hyoung;Lim, Chang-Mok;Jo, Jae-Hyun;Kim, Ju-hee;Kim, Su-Hwan;Lee, Ki-Young;Lee, Sang-Sik
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.12 no.3
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    • pp.290-298
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    • 2019
  • The proportion of farm households in the total population is decreasing every year. The aging of rural areas is expected to deepen. The aging of agriculture is continuing due to the aging of the aged population and the decline of the young population, and agricultural manpower shortage is emerging as a threat to agriculture and rural areas. The existing facility cultivation was concentrated on the production / yield per unit area. However, nowadays, not only production but also crop quality should be good so that the quality of crops must be improved because they can secure competitiveness in the market. Therefore, the government plans to increase the productivity by hi-techization of ICT infrastructure horticulture and to plan the dissemination of energy saving smart greenhouse. Therefore, it is necessary to develop a Smart Farm convergence service system based on a hybrid algorithm to enhance diversity and connectivity. Therefore, this study aims to develop smart farm convergence service system which collects data of growth environment of the rhizosphere environment of crops by wireless and monitor smartphone.

The Evaluation of flexure performance of SCP modules for LNG outer tank (LNG 외조탱크 적용을 위한 SCP 모듈의 휨성능 평가)

  • Park, Jung-Jun;Park, Gi-Joon;Kim, Sung-Wook;Kim, Eon;Shin, Dongkyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.1
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    • pp.447-455
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    • 2019
  • When constructing LNG storage structures using the cast-in-place method in extreme areas, the construction cost and time may be increased due to the poor working environments and conditions. Therefore, demand for modular energy storage tanks is increasing. In this study, we propose using an SCP module as an alternative for lighter-weight LNG storage tanks. The purpose of this study is to evaluate the feasibility of LNG storage outer tanks by performing bending tests on the thickness of composite steel plate concrete under field conditions. The loads on specimens with thicknesses of 100 mm and 200 mm were linearly increased to the design final loads of 413 kN and 822 kN, respectively. The slope was rapidly changed, and fracture occurred. The two test conditions showed linear behavior until the steel plate yielded, and after an extreme load behavior, sudden yielding of the steel plate yield occurred in the SCP bending test according to the INCA guidelines. The results satisfied the design flexural load and showed the possibility of using the specimens in a modular LNG outer tank. However, it is necessary to evaluate the structural performance of the SCP by performing compression and shear tests in future research.

A basic study on the hazard of hydrogen feul cell vehicles in road tunnels (도로터널에서 수소차 위험에 관한 기초적 연구)

  • Ryu, Ji-Oh;Lee, Hu-Young
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.23 no.1
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    • pp.47-60
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    • 2021
  • Hydrogen is a next-generation energy source, and according to the roadmap for activating the hydrogen economy, it is expected that industries to stably produce, store, and transport of hydrogen as well as the supply of hydrogen fuel cell vehicles will be made rapidly. Accordingly, safety measures for accidents of hydrogen vehicles in confined spaces such as tunnels are required. In this study, as part of a study to ensure the safety of hydrogen fuel cell vehicles in road tunnels, a basic investigation and research on the risk of fire and explosion due to gas leakage and hydrogen tank rupture among various hazards caused by hydrogen fuel cell vehicle accidents in tunnels was conducted. The following results were obtained. In the event of hydrogen fuel cell vehicle accidents, the gas release rate depends on the orifice diameter of TPRD, and when the gas is ignited, the maximum heat release rate reaches 3.22~51.36 MW (orifice diameter: 1~4 mm) depending on the orifice diameter but the duration times are short. Therefore, it was analyzed that there was little increase in risk due to fire. As the overpressure of the gas explosion was calculated by the equivalent TNT method, in the case of yield of VCE of 0.2 is applied, the safety threshold distance is analyzed to be about 35 m, and number of the equivalent fatalities are conservatively predicted to reach tens of people.

An Experimental study on the Structural Performance by the Depth Variation of Capacity of U-shaped composite Beam (U-형 복합보의 춤 변화에 따른 구조성능에 관한 실험적 연구)

  • Ha, Sang-Su
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.5
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    • pp.111-118
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    • 2020
  • The U-shaped composite beam used in this study consist of a reinforced concrete structure, a beam steel structure supporting the slab, a reinforced concrete structure, and a U-shaped steel plate. The U-shaped composite beam was developed for the purpose of using it as a parking lot because it is highly constructible and has low floor height and long span. For the improvement of constructivity, the U-shaped composite beam ends are planned with standardized H-shaped steel and connected directly to the columns, and the middle of the U-shaped composite beam consists of U-shaped steel plates folded in U-shaped form using thin steel plates (t=6) instead of H-shaped steel. In the middle of the composite beam, where U-shaped steel plates are located, the depth of U-shaped beam may be planned to be small so as to satisfy the height limit of the parking lot. It is important to grasp the structural performance according to the change of depth because low beam depth is advantageous for the reduction of the floor height, but it is a inhibitor to the structural behaviors of U-shaped composite beam. In addition, since U-shaped composite beams are a mixture of steel frame structures, reinforced concrete structures and U-shaped steel plates, securing unity has a great influence on securing structural performance. Therefore, in this study, a structural experiment was conducted to understand the structural performance according to the depth change for U-shaped composite beam. A total of three specimens were planned, including two specimens that changed the depth using a criteria specimen planned for a general parking lot. The results of the experiment showed that the specimens who planned the depth greatly had better structural performance such as yield strength, maximum strength, and energy than the standard specimen.

SPH-Based Wave Tank Simulations (SPH 기법 기반의 파동수조 시뮬레이션)

  • Lee, Sangmin;Kim, Mujong;Ko, Kwonhwan;Hong, Jung-Wuk
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.34 no.1
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    • pp.59-69
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    • 2021
  • Recently, large-scale offshore and coastal structures have been constructed owing to the increasing interest in eco-friendly energy development. To achieve this, precise simulations of waves are necessary to ensure the safe operations of marine structures. Several experiments are required in the field to understand the offshore wave; however, in terms of scale, it is difficult to control variables, and the cost is significant. In this study, numerical waves under various wave conditions are produced using a piston-type wavemaker, and the produced wave profiles are verified by comparing with the results from a numerical wave tank (NWT) modeled using the smoothed particle hydrodynamics (SPH) method and theoretical equations. To minimize the effect by the reflected wave, a mass-weighted damping zone is set at the right end of the NWT, and therefore, stable and uniform waves are simulated. The waves are generated using the linear and Stokes wave theories, and it is observed that the numerical wave profiles calculated by the Stokes wave theory yield high accuracy. When the relative depth is smaller than two, the results show good agreement irrespective of the wave steepness. However, when the relative depth and wave steepness are larger than 2 and 0.04, respectively, the errors are negligible if the measurement position is close to the excitation plate. However, the error is 10% or larger if the measurement position is away from the excitation location. Applicable target wave ranges are confirmed through various case studies.

Recycle of Unburned Carbon and Microceramics as Alternatives to Rubber Weight-Adding Materials and Polypropylene Filling Agents (고무증량재 및 플라스틱 충진재의 대체재로 UC와 CM의 재활용)

  • Han, Gwang Su;Kim, Dul-Sun;Lee, Dong-Keun
    • Clean Technology
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    • v.27 no.1
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    • pp.24-32
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    • 2021
  • Unburned carbon (UC) was successfully separated from fly ash by up to 85.8% in weight via froth flotation using soybean oil as a collector. An 18 wt% yield of microceramics (CM) could be achieved by employing a hydro cyclone separator located immediately after the flotation equipment. UC and CM were tested as alternatives to weight-adding material and polymer (especially polypropylene in this study) filler, respectively. Large particles of UC were broken down into smaller ones via ball milling to have an average particle diameter of 10.2 ㎛. When crushed UC was used as an alternative to clay as a rubber weight-adding material, a somewhat lower tensile strength and elongation rate than the allowed values were unfortunately obtained. In order to satisfy the standard limits, further treatment of UC is required to enhance surface energy for more intimate bonding with rubber. CM was observed in spherical forms with an average diameter of 5 ㎛. The surface of the CM particles was modified with phenol, polyol, stearic acid, and oleic acid so that the surface modified CM could be used as a polypropylene-filling agent. The flowability was good, but due to the lack of coupling forces with polypropylene, successful impact strength and flexural strength could not be obtained. However, when mixing the surface-modified CM with 1% silane by weight, a drastic increase in both the impact strength and flexural strength were obtained.

Effect of External Light Environment and Growing Degree Days on Strawberry Production (외부 광환경 및 생육도일온도가 딸기 생산량에 미치는 영향)

  • Lee, Taeseok;Kim, Jingu;Park, Seokho;Lee, Jaehan;Han, Kilsu;Moon, Jongpil
    • Journal of Bio-Environment Control
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    • v.31 no.4
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    • pp.432-437
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    • 2022
  • In this study, strawberries were grown during the two cultivation periods (first: 2020-2021, second: 2021-2022) to analyze the effect of the external light environment and growing degree days (GDD) on crop production. The temperature and humidity during day in a greenhouse in each cultivation period were similarly managed. At night, there was a statistical difference in temperature and humidity in the greenhouse between two periods. The accumulated solar radiation during the first cultivation period was high in September and October. Since January, the accumulated solar radiation during the second cultivation period was high. In the second cultivation period, the initial yield was small because the accumulated solar radiation and GDD was small. But accumulated yields and potential maximum yields in second cultivation period were larger than yields in the first cultivation period as the accumulated solar radiation and GDD increased. The sugar contents of strawberry decreased as GDD increased.

Crash Safety Evaluation of LNG Fuel Containers for Vehicles using ANSYS Explicit Dynamics (ANSYS Explicit Dynamics 해석을 활용한 차량용 LNG 용기의 충돌안전성 평가)

  • Nam, SuHyun;Kim, JiYu;Kim, EuiSoo
    • Journal of the Korean Institute of Gas
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    • v.26 no.4
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    • pp.58-63
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    • 2022
  • With the emergence of environmental problems caused by fine dust worldwide, LNG, which is cheaper and less pollution than diesel, is attracting attention as the next generation energy of automobiles and is expanding its supply. However, it is difficult to operate smoothly due to the lack of infrastructure for LNG charging stations in Korea and the limited size of containers that can be installed according to regulations. In Korea, research and development on the contents of containers for the smooth operation of natural gas vehicles are underway, but there is a problem that the container directly receives the impact of the vehicle collision and explodes, causing a major disaster. Therefore, in this study, the safety of the container was verified by deriving the strain and stress values through ANSYS Explicit Dynamics analysis. As a result, a maximum stress of 565.37MPa occurred in the container, and it is expected that plastic deformation will occur as it exceeds the yield stress of STS304 used as a material for the container, which is beyond 505MPa. When an impact caused by a collision between a vehicle and a container is applied, it is considered necessary to design a support or reinforcement because the container may be damaged or defective.