• Title/Summary/Keyword: Carbon Balance

Search Result 262, Processing Time 0.029 seconds

Chemical Fluxes at the Sediment-Water Interface Below Marine Fish Cages on the Coastal Waters off Tong-Young, South Coast of Korea (남해안 통영지역 가두리양식장 해수-퇴적물 경계면에서의 chemical fluxes)

  • Shim, Jeong-Hee;Kang, Young-Chul;Choi, Jin-Woo
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
    • /
    • v.2 no.2
    • /
    • pp.151-159
    • /
    • 1997
  • Benthic respiration and chemical fluxes were measured at the sediment-water interface underlying the marine fish cages floating on the open coastal waters off Tong-Young, the South Coast of Korea. The effects of cage farming on coastal benthic environment and on mass balance of organic carbon in the benthic boundary layer under the marine fish cages are addressed. In a growing season of caged fishes of June, 1995, benthic chambers and sediment traps were deployed on the sediment-water interfaces of the two sites chosen for this study: 1) Cage Site, directly underlying the fish cages of the farm at 18 m water depth, and 2) Control Site, about 100 m away from the farm at 32 m water depth. Benthic respiration rates and chemical fluxes were calculated from the evolution of dissolved oxygen and chemicals in the chamber water, and mass balance of organic carbon in the benthic boundary layer was constructed based on the vertical flux of particulate organic matter (POM) and chemical fluxes out of the sediment. High organic dumping (6400 mg C $m^{-2}d^{-1}$) and high benthic respiration (230 mmol $O_2\;m^{-2}d^{-1}$) were observed at the Cage Site. Equivalent to 40% of vertical flux of organic carbon into the Cage Site seemed to be decomposed concurrently and released back to overlying waters (2400 mg C $m^{-2}d^{-1}$). Consequently, up to 4000 mg C $m^{-2}d^{-1}$ of organic carbon could be buried into the farm sediment (equivalent to 60% of organic carbon flux into the Cage Site). At the Control Site, relatively less input of organic carbon (4000 mg C $m^{-2}d^{-1}$) and low benthic respiration rate (75 mmol $O_2\;m^{-2}d^{-1}$) were observed despite short distance away from the cages. The influence of cage farming on benthic chemical fluxes might be restricted and concentrated in the sea bottom just below the fish cages in spite of massive organic dumping and high current regime around the fish cage farm.

  • PDF

Rewiring carbon catabolite repression for microbial cell factory

  • Vinuselvi, Parisutham;Kim, Min-Kyung;Lee, Sung-Kuk;Ghim, Cheol-Min
    • BMB Reports
    • /
    • v.45 no.2
    • /
    • pp.59-70
    • /
    • 2012
  • Carbon catabolite repression (CCR) is a key regulatory system found in most microorganisms that ensures preferential utilization of energy-efficient carbon sources. CCR helps microorganisms obtain a proper balance between their metabolic capacity and the maximum sugar uptake capability. It also constrains the deregulated utilization of a preferred cognate substrate, enabling microorganisms to survive and dominate in natural environments. On the other side of the same coin lies the tenacious bottleneck in microbial production of bioproducts that employs a combination of carbon sources in varied proportion, such as lignocellulose-derived sugar mixtures. Preferential sugar uptake combined with the transcriptional and/or enzymatic exclusion of less preferred sugars turns out one of the major barriers in increasing the yield and productivity of fermentation process. Accumulation of the unused substrate also complicates the downstream processes used to extract the desired product. To overcome this difficulty and to develop tailor-made strains for specific metabolic engineering goals, quantitative and systemic understanding of the molecular interaction map behind CCR is a prerequisite. Here we comparatively review the universal and strain-specific features of CCR circuitry and discuss the recent efforts in developing synthetic cell factories devoid of CCR particularly for lignocellulose-based biorefinery.

Effect of Passenger Car Fuel Consumptions and Fuel Cost Savings by Hi-Pass System (하이패스 이용시 승용차 연료소모 및 연료비용 절감효과)

  • Kwak, Jin-Ho;Kim, Dong-Nyong;Jeong, Ae-Ra
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.14 no.1
    • /
    • pp.94-102
    • /
    • 2015
  • The high-pass(brand name of Electronic Toll Collection System) utilization trend on the highway continues to grow as 59.4% (by the end of 2013). In this study, we applied the carbon balance method using a fuel chassis dynamometer with the four passenger car classes in order to measure the fuel consumption of the car using the expressway tollgate. We experimented 18 driving mode at general tollgate and high-pass tollgate. As a result, in case of entry/exit toll there were 21.0~56.4ml/veh fuel consumption savings, in case of open toll fuel consumption savings was analyzed as 10.5~28.1ml/veh. In addition, the annual fuel cost savings by virtue of high-pass was 28.2~57.3 billion won at 70% utilization rate, 32.2~65.5 billion won at 80%, 36.2~73.7 billion won at 90% and 40.3~81.9 billion won at 100%.

Design of a Logistics Decision Support System for Transportation Mode Selection considering Carbon Emission Cost (탄소배출비용을 고려한 물류의 최적 운송수단 의사결정 시스템 설계)

  • Song, Byung-Jun;Koo, Je-Kwon;Song, Sang-Hwa;Lee, Jong-Yun
    • The KIPS Transactions:PartD
    • /
    • v.18D no.5
    • /
    • pp.371-384
    • /
    • 2011
  • This paper considers logistics decision support system which deals with transportation mode selection considering transportation and carbon emission cost. Transportation and carbon emission costs vary with the choice of transportation modes and to become competitive companies need to find proper transportation modes for their logistics services. However, due to the restricted capacity of transportation modes, it is difficult to balance transportation and carbon emission costs when designing logistics network including transportation mode choice for each service. Therefore this paper aims to analyze the trade-off relationship between transportation and carbon emission cost in mode selection of intermodal transportation and to provide optimal green logistics strategy. In this paper, the logistics decision support system is designed based on mixed integer programming model. To understand the trade-off relationship of transportation and carbon emission cost, the system is tested with various scenarios including transportation of containers between Seoul and Busan. The analysis results show that, even though sea transportation combined with trucking is competitive in carbon emission per unit distance travelled, the total cost of carbon emission and transportation for the sea transportation may not have competitive advantage over other transportation modes including rail and truck transportation modes. The sea-based intermodal logistics service may induce detours which have negative impacts on the overall carbon emission. The proposed logistics decision support system is expected to play key role in green logistics and supply chain management.

Biogeochemical Organic Carbon Cycles in the Intertidal Sandy Sediment of Nakdong Estuary (낙동강 하구 갯벌 사질 퇴적물에서 생지화학적 유기탄소순환)

  • Lee, Jae-Seong;Park, Mi-Ok;An, Soon-Mo;Kim, Seong-Gil;Kim, Seong-Soo;Jung, Rae-Hong;Park, Jong-Soo;Jin, Hyun-Gook
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
    • /
    • v.12 no.4
    • /
    • pp.349-358
    • /
    • 2007
  • In order to understand biogeochemical cycles of organic carbon in the permeable intertidal sandy sediments of the Nakdong estuary, we estimated the organic carbon production and consumption rates both in situ and in the laboratory. The Chl-a content of the sediment and the nutrient concentrations in below surface pore water in the sandy sediment were lower than in the muddy sediment. The sediment oxygen consumption rates were relatively high, especially when compared with rates reported from other coastal muddy sediments with higher organic carbon contents. This implied that both the organic carbon degradation and material transport in the sandy sediment were enhanced by advection-related process. The simple mass balance estimation of organic carbon fluxes showed that the major sources of carbon in the sediment would originate from benthic microalgae and detrital organic carbon derived from salt marsh. The daily natural biocatalzed filtration, extrapolated from filtration rates and the total area of the Nakdong estuary, was one order higher than the maximum capability of sewage plants in Busan metropolitan city. This implies that the sandy sediment contributes greatly to biogeochemical purification in the area, and is important for the re-distribution of materials in the coastal environment.

Enhanced mass balance Tafel slope model for computer based FEM computation of corrosion rate of steel reinforced concrete coupled with CO2 transport

  • Hussain, Raja Rizwan
    • Computers and Concrete
    • /
    • v.8 no.2
    • /
    • pp.177-192
    • /
    • 2011
  • This research paper aims at computer based modeling of carbonation induced corrosion under extreme conditions and its experimental verification by incorporating enhanced electrochemical and mass balance equations based on thermo-hygro physics with strong coupling of mass transport and equilibrium in micro-pore structure of carbonated concrete for which the previous research data is limited. In this paper the carbonation induced electrochemical corrosion model is developed and coupled with carbon dioxide transport computational model by the use of a concrete durability computer based model DuCOM developed by our research group at concrete laboratory in the University of Tokyo and its reliability is checked in the light of experiment results of carbonation induced corrosion mass loss obtained in this research. The comparison of model analysis and experiment results shows a fair agreement. The carbonation induced corrosion model computation reasonably predicts the quantitative behavior of corrosion rate for normal air dry relative humidity conditions. The computational model developed also shows fair qualitative corrosion rate simulation and analysis for various pH levels and coupled environmental actions of chloride and carbonation. Detailed verification of the model for the quantitative carbonation induced corrosion rate computation under varying relative conditions, different pH levels and combined effects of carbonation and chloride attack remain as scope for future research.

Effect of retained austenite on mechanical properties in medium carbon steel (중탄소강의 기계적성질에 미치는 잔류오스테나이트의 영향)

  • Sun, C.G.;Kim, Y.H.;Kim, H.G.
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.8 no.3
    • /
    • pp.229-235
    • /
    • 1995
  • We were studied to the effect of alloying element and retained austenite on a mechnical properties and that used steels were composed three types composition. According to the soaking temperature, a retained austenite was pricipitated in the bainitic ferrite matrix and it was pricipitated to a flake type of about $2{\mu}m$, a mixture of massive and bar type and a flake type of about $1{\mu}m$ size. Through x-ray diffraction analysis, the amount of retained austenite was increased with addition of Si and Ni for equal heat treatment condition and it was best abundanted in the soaking temperature of $855^{\circ}C$. The balance value of strength and elongation were complexly controlled not only a retained austenite formation but also a formation characteristic and shape of the retained austenite and bainite. The balance value of strength and elongation were most satisfactory obtained with "B" and "C" specimens in a firstly heat treated at $855^{\circ}C$ and the best result was that a $2840kg/mm^2.%$ with the heat teratment condition of $855^{\circ}C-400^{\circ}C$ used for "C" specimen.

  • PDF

Analysis of Respiratory Gas by Training on Healthcare Indoor Bicycle (헬스케어용 실내 자전거 운동에 의한 호흡가스 분석)

  • Hong, Chul-Un;Kang, Hyung-Sub;Kim, Gi-Beum
    • Journal of Biomedical Engineering Research
    • /
    • v.30 no.2
    • /
    • pp.147-152
    • /
    • 2009
  • This study was conducted to observe the change of limbs stroke and respiration gas parameters in our new bicycle fitness system. We hypothesized that the variable force of left and right limbs might be effective for sensing stimulation in modified new unequal pedal bicycle system. It has been developed, which can provide visual information and different length of pedal with left and right limbs. Experimental results showed different activities between the left and right limbs where the activity of the left limb increased than that of right limb. Especially, the soleous muscle activity increased both in control and experimental groups by this training method. But oxygen and carbon dioxide partial pressures in respiratory gas increased during training method. These results suggest that acidosis of blood was led by this process. Consequently, this bicycle training is concluded that aerobic training could affect different limb activities. Finally, we expect that our new bicycle system will be effective for healthcare with proper balance between the left and right limbs.

Metabolic Engineering of Saccharomyces cerevisiae for Redox Balance of Xylose Fermentation

  • Kim, Soo Rin;Jin, Yong-Su
    • Current Research on Agriculture and Life Sciences
    • /
    • v.32 no.4
    • /
    • pp.199-202
    • /
    • 2014
  • The bioconversion of cellulosic biomass hydrolyzates consisting mainly of glucose and xylose requires the use of engineered Saccharomyces cerevisiae expressing a heterologous xylose pathway. However, there is concern that a fungal xylose pathway consisting of NADPH-specific xylose reductase (XR) and $NAD^+$-specific xylitol dehydrogenase (XDH) may result in a cellular redox imbalance. However, the glycerol biosynthesis and glycerol degradation pathways of S. cerevisiae, termed here as the glycerol cycle, has the potential to balance the cofactor requirements for xylose metabolism, as it produces NADPH by consuming NADH at the expense of one mole of ATP. Therefore, this study tested if the glycerol cycle could improve the xylose metabolism of engineered S. cerevisiae by cofactor balancing, as predicted by an in-silico analysis using elementary flux mode (EFM). When the GPD1 gene, the first step of the glycerol cycle, was overexpressed in the XR/XDH-expressing S. cerevisiae, the glycerol production significantly increased, while the xylitol and ethanol yields became negligible. The reduced xylitol yield suggests that enough $NAD^+$ was supplied for XDH by the glycerol cycle. However, the GPD1 overexpression completely shifted the carbon flux from ethanol to glycerol. Thus, moderate expression of GPD1 may be necessary to achieve improved ethanol production through the cofactor balancing.

A Study on Combustion Characteristics of the Bio-drying SRF in 5 Ton/day Scale Combustion Boiler (5톤/일 규모의 연소보일러에서 Bio-drying 고형연료의 연소특성 연구)

  • Kim, Dong-Ju;Yoon, Young-Sik;Jeong, Bup-Mook;Park, Yeong Su;Seo, Yong-Chil;Lee, Byung-Sun
    • Journal of Korea Society of Waste Management
    • /
    • v.35 no.7
    • /
    • pp.600-605
    • /
    • 2018
  • In this study, the combustion characteristics were investigated based on the biodrying solid recovered fuel (SRF) in a 5 Ton/day scale combustion boiler. The composition of the combustion gas containing the biodrying SRF was analyzed, the particulate matter, and its HCl content was determined with the air pollutant process test method. Mass balance, carbon balance, and combustion efficiency were calculated according to the equivalence ratio (ER) method; the energy recovery efficiency of the combustion boiler was also analyzed. The overall combustion efficiency of the biodrying SRF was 97.3 % and the energy recovery efficiency was 80.2%.