• Title/Summary/Keyword: $CO_2$ supply

Search Result 768, Processing Time 0.031 seconds

Performance characteristics of a single-cylinder power tiller engine with biodiesel produced from mixed waste cooking oil

  • Choi, Hwon;Woo, Duk Gam;Kim, Tae Han
    • Korean Journal of Agricultural Science
    • /
    • v.47 no.1
    • /
    • pp.29-41
    • /
    • 2020
  • Biodiesel is a clean energy resource that can replace diesel as fuel, which can be used without any structural changes to the engine. Vegetable oil accounts for 95 percent of the raw materials used to produce biodiesel. Thus, many problems can arise, such as rising prices of food resources and an imbalance between supply and demand. Most of the previous studies using waste cooking oil used waste cooking oil from a single material. However, the waste cooking oil that is actually collected is a mixture of various types of waste cooking oil. Therefore, in this study, biodiesel produced with mixed waste cooking oil was supplied to an agricultural single-cylinder diesel engine to assess its potential as an alternative fuel. Based on the results, the brake specific fuel consumption (BSFC) increased compared to diesel, and the axis power decreased to between 70 and 99% compared to the diesel. For emissions, NOx and CO2 were increased, but CO and HC were decreased by up to 1 to 7% and 16 to 48%, respectively, compared to diesel. The emission characteristics of the mixed waste cooking oil biodiesel used in this study were shown to be similar to those of conventional vegetable biodiesel, confirming its potential as a fuel for mixed waste cooking oil biodiesel.

Soot and PAH Formation Characteristic of Concentric Co-Flow Diffusion Flames (이중동축류 확산화염에서의 매연 및 PAH 생성 특성)

  • Lee, Won-Nam;Nam, Youn-Woo
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.13 no.2
    • /
    • pp.178-185
    • /
    • 2005
  • The synergistic effect of ethylene/propane mixture on soot formation is studied experimentally using a concentric co-flow diffusion burner, which provides the stratified fuel mixture. The soot volume fraction, soot particle diameter, number density and PAH concentrations are measured with various fuel supply configurations and compared to the homogeneously mixed case. When propane is supplied through the inner nozzle, an increase of soot formation is observed. However, when propane is supplied through the outer nozzle, a decrease is observed. The reaction path of PAH's formed from the pyrolysis process of propane is likely to be responsible to the observed differences. When propane is supplied through the outer nozzle, PAH's are formed in the relatively near oxidation region and exposed to the oxidization environment; on the other hand, when propane is supplied through the inner nozzle, PAH's are not likely to be oxidized and thus get involved in soot formation process. The synergistic effect in ethylene/propane diffusion flames is found to be affected not only by the com position of the mixture but also by the way of mixing.

Effect of Injection Pressure on Low Temperature Combustion in CI Engines (압축착화 엔진에서 분사압이 저온연소에 미치는 영향)

  • Jang, Jaehoon;Lee, Sunyoup;Lee, Yonggyu;Oh, Seungmook;Lee, Kihyung
    • Journal of ILASS-Korea
    • /
    • v.18 no.1
    • /
    • pp.21-26
    • /
    • 2013
  • Diesel low temperature combustion (LTC) is the concept where fuel is burned at a low temperature oxidation regime so that $NO_x$ and particulate matters (PM) can simultaneously be reduced. There are two ways to realize low temperature combustion in compression ignition engines. One is to supply a large amount of EGR gas combined with advanced fuel injection timing. The other is to use a moderate level of EGR with fuel injection at near TDC which is generally called Modulated kinetics (MK) method. In this study, the effects of fuel injection pressure on performance and emissions of a single cylinder engine were evaluated using the latter approach. The engine test results show that MK operations were successfully achieved over a range of with 950 to 1050 bar in injection pressure with 16% $O_2$ concentration, and $NO_x$ and PM were significantly suppressed at the same time. In addition, with an increase in fuel injection pressure, the levels of smoke, THC and CO were decreased while $NO_x$ emissions were increased. Moreover, as fuel injection timing retarded to TDC, more THC and CO emissions were generated, but smoke and $NO_x$ were decreased.

An X-Ku Band Distributed GaN LNA MMIC with High Gain

  • Kim, Dongmin;Lee, Dong-Ho;Sim, Sanghoon;Jeon, Laurence;Hong, Songcheol
    • JSTS:Journal of Semiconductor Technology and Science
    • /
    • v.14 no.6
    • /
    • pp.818-823
    • /
    • 2014
  • A high-gain wideband low noise amplifier (LNA) using $0.25-{\mu}m$ Gallium-Nitride (GaN) MMIC technology is presented. The LNA shows 8 GHz to 15 GHz operation by a distributed amplifier architecture and high gain with an additional common source amplifier as a mid-stage. The measurement results show a flat gain of $25.1{\pm}0.8dB$ and input and output matching of -12 dB for all targeted frequencies. The measured minimum noise figure is 2.8 dB at 12.6 GHz and below 3.6 dB across all frequencies. It consumes 98 mA with a 10-V supply. By adjusting the gate voltage of the mid-stage common source amplifier, the overall gain is controlled stably from 13 dB to 24 dB with no significant variations of the input and output matching.

Key Indicators for the Growth of Logistics and Distribution Tech Startups in Thailand

  • Thanatchaporn JARUWANAKUL
    • Journal of Distribution Science
    • /
    • v.21 no.2
    • /
    • pp.35-43
    • /
    • 2023
  • Purpose: As Thailand seeks to become a regional startup hub, Thai startups have been acquiring growth and scalability in the last ten years. Hence, this paper examines influential factors in Thailand's growth of logistics tech startups. The conceptual framework incorporates sensing user needs, sensing technological options, conceptualizing, scaling, and stretching, co-producing, and orchestrating, business strategy, strategic flexibility, and startup growth. Research design, data, and methodology: The quantitative method was applied to distribute the questionnaire to 500 managers and above in logistics tech startups in Thailand. The sampling techniques involve judgmental, convenience, and snowball samplings. Before the data collection, The Item Objective Congruence (IOC) Index and pilot test (n=45) were employed for content validity and reliability. The data were mainly analyzed by Confirmatory Factor Analysis (CFA) and Structural Equation Model (SEM). Results: The findings revealed that sensing technological options, scaling, and stretching, co-producing, and orchestrating, and business strategy significantly influence the growth of startups in Thailand. Nevertheless, sensing user needs, conceptualizing, and strategic flexibility have no significant relationship with startup growth. Conclusions: For Thailand to accelerate its digital economy driven by tech startups, firms must emphasize influential factors to accelerate growth by providing the right tech solutions for people's lives.

Impact of the Geochemical Characteristics and Potential Contaminants Source of Surrounding Soil on Contamination of a Reservoir in an Island (II) - Appraisal of flow categorized by Incursion Using Rainfall-Runoff Model - (주변토양의 지구화학적 특성과 잠재적 오염원이 도서지역 저수지의 오염부하에 미치는 영향(II) - 강우 유출 모형을 이용한 유입경로별 유출량 평가 -)

  • Park, Sun-Hwan;Park, Wan-Sub;Jun, Young-Bong;Kim, Chang-Gyun;Kim, Sung-Gou;Kang, Seon-Hong;Chang, Yoon-Young;Jeong, Jeong-Ho;Jung, Jong-Ahm
    • Journal of Environmental Impact Assessment
    • /
    • v.19 no.3
    • /
    • pp.215-222
    • /
    • 2010
  • This research aims to gain the result of assessment of inflow categorized by runoff path using DIROM (Daily Irrigation Reservoir Operation Model) for Baengnyeong-myeon reservior which was built for residents of Baengnyeong island to solve the shortage of drinking water and stable supply of domestic water. The simulation results of DIROM and actual hydrograph of the reservoir show very low correlation with geological characteristics. The simulation results by DIROM after adjusting with modified Tank III model which considers all outflow from Tank II model as interflow among 3 level tanks show good correlation of its regional runoff and inflow characteristics with $R^2$=0.9058. In the study area, diffluence of 37% of rain fall of the study year has been simulated, which shows low result compared to the average river runoff of national water resource. In addition, 34.5% of total inflow to the study reservoir is mainly interflow and baseflow among expected several channels.

Studies for alternative material of media for Pleurotus eryngii (큰느타리버섯 배지재료의 다변화를 위한 연구)

  • Park, Jin-Young;Lee, Jae-Yun;Kim, Hyun-Tae;Kim, Sam-Soo;Kim, Sung-Yun;Kim, Mun-Ock;Lee, Jae-Dong
    • Journal of Mushroom
    • /
    • v.4 no.3
    • /
    • pp.88-100
    • /
    • 2006
  • This study was performed to investigate the effective components of media of Pleurotus eryngii for bottle cultivation and several alternative material for reducing cost and smooth supply. The results show that Potato starch, Cocoa shell, Corn gluten feed, Soybean flour(solvent extracted), Cottonseed hull, Poultry manure can be replaced in Bean curd dregs of basal substrates. Especially addition of Soybean flour at 2~8% and Poulty manure at 2% in place of Bean curd dregs is effective for mycelial growth of P. eryngii, Also Pine sawdust appears that can be replaced by Softwood sawdust and addition of softwood sawdust at 25.2% is most effective. Addition of $CaCO_3$, at 2~3%, $K_2CO_3$, at 0.2%, $MgSO_4{\cdot}7H_2O$ in 0.1%, $MnSO_4{\cdot}5H_2O$ in 0.05% is effective for mycelial growth of P. eryngii, Activation materials used in this study have not enough benefit for mycelial growth in the financial aspect.

  • PDF

Textural and Geochemical Characteristics of Ferromanganese Crusts from the Lomilik and Litakpooki Seamounts, Marshall Islands, West Pacific (서태평양 마샬제도 Lomilik와 Litakpooki 해저산 망간각의 조직 및 지화학적 특성)

  • Woo, Kyeong-Sik;Park, Sung-Hyun;Jung, Hoi-Soo;Moon, Jai-Yoon;Lee, Kyeong-Yong;Choi, Youn-Ji
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
    • /
    • v.6 no.1
    • /
    • pp.13-26
    • /
    • 2001
  • Six ferromanganese crusts from the Lomilik and Litatfooki seamounts in the Marshall Islands were analyzed for texture, geochemistry and stratigraphy to delineate the paleoceanographic conditions. The crusts can be divided into three layers; 1) outermost massive layer (Layer 1), 2) middle porous Fe-oxides rich layer infllled with biointemal clasts (Layer 2), and 3) innermost massive layer cemented and/or replaced by carbonate fluoapatite (CFA) (Layer 3). The Layer 1 contains higher Mn, Co, Ni, and Mg than other two layers, and the Layer 2 was relatively more enriched in Fe, Al, Ti, Ba, Cu, and Zn. However, the Layer 3 shows higher Ca and P and lower Mn, Fe, Co, and Ni contents than overlying two layers. Based on the Co-chronometry, the crusts are postulated to have begun to grow from 56-31 Ma (early Eocene to Oligocene). The boundaries between layers 1 and 2, and layers 2 and 3 are dated to be 7-3 Ma and 26-14 Ma, respectively. High contents of Ca and P in Layer 3 clearly indicate that the layer had been phosphatized prior to the formation of Layer 2. Considering the well-preserved mjcrostructures in Layer 3, it is unlike that the crusts themselves were recrystallized in suboxic condition. Also, the lower Co concentrations in Layer 3 may imply that the Co supply was not constant during the formation of Layer 3. Layer 2, characterized by the porous texture, grew over Layer 3 during 26-9 Ma. Internal biogenic sediments including foraminifera within the original cavities and the enrichment of organophillic elements such as Ba, Cu, and Zn, suggest that Layer 2 have below high production regions. Also, high content of allumino silicate components may indicate increased terrigeneous input during the formation of Layer 2. The Layer 2. The Layer 1 has been subjected to little diagenetic influence since the Pliocene.

  • PDF

Applicability of Fuel Supply System for HCNG Engine (HCNG 엔진용 연료시스템의 적용성 평가)

  • Lee, Sungwon;Lim, Gihun;Park, Cheolwoong;Choi, Young;Kim, Changgi;Lee, Janghee
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.21 no.2
    • /
    • pp.146-153
    • /
    • 2013
  • CNG buses has contributed to improve air quality in cities. But it is difficult to meet the next emission regulations such as EURO-VI without the help of additional post-processing device. Hydorgen has higher flame speed and lower combustion temperature that make it thermal efficiency increase with leaner operation. Using hydrogen natural gas blend (HCNG) fuel is promising technology which can reduce $NO_x$ and $CO_2$ emissions for a natural gas vehicle. However, fuel flow rate of HCNG should be increased since hydrogen's energy density per volume is much smaller than natural gas. In the present study, the characteristics of fuel supply system and its applicability were evaluated in a heavy duty natural gas engine. The results showed that the potential of fuel pressure regulator and fuel metering valve had enough capacity with HCNG. Employed mixer did not affect the distribution characteristics of mixture.

A Study on the Effect of Group Heating in Rural Villages Using Poplar Wood Chips on Fuel Quality, Cost, and Atmospheric Environment (포플러 목재칩을 이용한 농산촌 마을 집단난방시 연료품질, 비용, 대기환경에 미치는 영향에 관한 연구)

  • An, Byeong-Il;Ko, Kyoung-Ho
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.64 no.2
    • /
    • pp.57-69
    • /
    • 2022
  • This study analyzes the fuel conditions and environmental effects of converting heating in rural villages that rely on fossil fuels into wood fuel. In particular, we tried to derive the most important considerations when using wooden chips as fuel in aging agricultural villages where various variables such as weather, facility characteristics, fuel quality, and maintenance capabilities work. Above all, an experiment was conducted by comparing it with oak trees to determine whether Italian poplar, a representative attribute water created to supply fuel wood in Korea, is suitable for heating fuel. Through experiments, 1) Even though the supply of poplar wood chips during 10 hours of operation was 60.74 kg less than that of hardwood chips, the production of hot water was 140 kWh higher. 2) The higher the exhaust gas temperature, the proportional (increase) oxygen concentration and inversely (decrease) PM and CO emissions. 3) Poplar has twice as much ash content as hardwood and three times more fine dust has been detected, but it meets all the standards for wood quality at the Korea Forest Science Institute. 4) Under the condition that there is a difference in water content (7.7%), hardwood cost 1.13 times more wood chips per 1 MWh than poplar, and even if the water content is corrected equally, hardwood cost 1.05 times more per 1 MWh than poplar. 5) In conclusion, it was proved that the fuel possibility, economic possibility, and environmental possibility of poplar wood chips are sufficient.