• Title, Summary, Keyword: Methane ($CH_4$)

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Correlation between Methane (CH4) Emissions and Root Aerenchyma of Rice Varieties

  • Kim, Woo-Jae;Bui, Liem T.;Chun, Jae-Buhm;McClung, Anna M.;Barnaby, Jinyoung Y.
    • Plant Breeding and Biotechnology
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    • v.6 no.4
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    • pp.381-390
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    • 2018
  • Percentage of aerenchyma area has been closely linked with amounts of methane emitted by rice. A diversity panel of 39 global rice varieties were examined to determine genetic variation for root transverse section (RTS), aerenchyma area, and % aerenchyma. RTS and aerenchyma area showed a strong positive correlation while there existed no significant correlation between RTS area and % aerenchyma. Five varieties previously shown to differ in methane emissions under field conditions were found to encompass the variation found in the diversity panel for RTS and aerenchyma area. These five varieties were evaluated in a greenhouse study to determine the relationship of RTS, aerenchyma area, and % aerenchyma with methane emissions. Methane emissions at physiological maturity were the highest for 'Rondo', followed by 'Jupiter', while 'Sabine', 'Francis' and 'CLXL745' emitted the least. The same varietal rank, 'Rondo' being the largest and 'CLXL745' the smallest, was observed with RTS and aerenchyma areas. RTS and aerenchyma area were significantly correlated with methane emissions, r = 0.61 and r = 0.57, respectively (P < 0.001); however, there was no relationship with % aerenchyma. Our results demonstrated that varieties with a larger root area also developed a larger aerenchyma area, which serves as a gas conduit, and as a result, methane emissions were increased. This study suggests that root transverse section area could be used as a means of selecting germplasm with reduced $CH_4$ emissions.

Diamond-like Carbon Films Synthesized from $CH_4$, $CH_4-H_2$, and $CH_4-Ar$ Plasmas (메탄, 메탄-수소 및 메탄-아르곤 플라즈마로부터 합성된 다이아몬드성 탄소막)

  • Choi, Y.;Hong, J. W.;Lee, H. W.;Song, J. S.
    • Journal of the Korean Vacuum Society
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    • v.4 no.1
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    • pp.12-17
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    • 1995
  • Diamondlike carbon(DLC)films having good characteristics in mechanical and optical properties, were synthesized by rf-plasma enhanced chemical vapor deposition method. Methane, methane-hydrogen, or methane-argon were used as source gases. The infrared transparency and composition of the films were investigate. Especially, the anti-reflection effect of KLC film in infrared region was confirmed by depositing it on Ge/Si sample. When DLC films were deposited on the plastic substrates and thermal distortion, which were originated before and during deposition, respectively, played a role as a crack source of the films.

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Effect of Fodder Tree Species with Condensed Tannin Contents on In vitro Methane Production

  • Vazquez, Ernestina Gutierrez;Medina, Leonardo Hernandez;Benavides, Liliana Marquez;Caratachea, Aureliano Juarez;Razo, Guillermo Salas;Burgos, Armin Javier Ayala;Rodriguez, Ruy Ortiz
    • Asian-Australasian Journal of Animal Sciences
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    • v.29 no.1
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    • pp.73-79
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    • 2016
  • The objective was to evaluate the effect of fodder tree species (FTS) with condensed tannin contents: Cordia elaeagnoides, Platymiscium lasiocarpum, Vitex mollis, and Haematoxylon brasiletto, on in vitro methane ($CH_4$) production at 24 h post incubation. The analysis was performed using the in vitro gas production technique, with three levels of inclusion/species: 600, 800, and 1,000 mg and with 4 replicates/species/level of inclusion. The substrate was incubated at $39^{\circ}C$, and the gas and $CH_4$ production were recorded at 4, 8, 12, and 24 h post incubation. The data collected was analyzed through Pearson correlation, polinomial regression and fixed effects models. There were negative correlations between FTS-total gas volume (r = -0.40; p<0.001); FTS-volume of $CH_4$ produced (r = -0.40; p<0.001) and between the inclusion level-volume of $CH_4$ produced (r = -0.20; p<0.001). As well as a positive correlation between hours post incubation-total gas volume (r = 0.42; p<0.001) and between hours post incubation-volume of $CH_4$ produced (r = 0.48; p<0.001). The FTS: C. elaeagnoides, V. mollis, and H. brasiletto have potential, in the three inclusion levels analyzed, to reduce $CH_4$ emission on in vitro trials (>32.7%), taking into account the total $CH_4$ production at 24 h of the forage used as reference (Avena sativa). It's suggested that C. elaeagnoides-according to its crude protein, neutral detergent fiber, and condensed tannins content- is the best alternative within the FTS analyzed, for feeding ruminants and for the control of $CH_4$ emissions during the dry season.

Estimation of Ultimate Methane and Hydrogen Sulfide Yields for C&D Waste and MSW Using BMP Test (건설폐기물, 생활폐기물의 용출특성 분석과 BMP test를 통한 최종메탄(CH4) 및 황화수소(H2S) 수율 산정)

  • Jung, Sukyoung;Jeong, Seongyeob;Chang, Soonwoong
    • New & Renewable Energy
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    • v.10 no.1
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    • pp.30-40
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    • 2014
  • The main object of this study was to offer information about incoming waste in landfill and to evaluate biochemical methane and hydrogen sulfide potentials of landfill wastes. We examined brick, soil, mixed waste (C&D waste and MSW) samples for the study. The leaching experiments showed that BOD, COD and sulfate were determined in the range of 0~18,816 mg/kg, 85~21,100 mg/kg and 160~1,205 mg/kg, respectively in 6hr extraction test. An accumulated extraction tests for 140day were determined BOD 226~197,219 mg/kg, COD 436~242,588 mg/kg and Sulfate 1,090~25,140 mg/kg. Also, BMP (biochemical methane potential) tests were carried out to examine methane and hydrogen sulfide yields for the 3 different wastes. As a result, methane yield was determined to 262.68 mL $CH_4/g$ VS of MSW and 0~17.75 mL $CH_4/g$ VS in brick, soil and C&D waste. Higher hydrogen sulfide yield was observed to 0.079mL $H_2S/g$ VS in C&D waste. This result indicate that brick and soil could be sources of sulfate, and higher production of hydrogen sulfide could be odor problem and inhibitor of methane production.

Indirect Estimation of CH4 from Livestock Feeds through TOCs Evaluation

  • Kim, M.J.;Lee, J.S.;Kumar, S.;Rahman, M.M.;Shin, J.S.;Ra, C.S.
    • Asian-Australasian Journal of Animal Sciences
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    • v.25 no.4
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    • pp.496-501
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    • 2012
  • Thirty-five available feeds were fermented in vitro in order to investigate their soluble total organic carbon (TOCs) and methane ($CH_4$) production rate. A fermentation reactor was designed to capture the $CH_4$ gas emitted and to collect liquor from the reactor during in vitro fermentation. The results showed that $CH_4$ production rate greatly varied among feeds with different ingredients. The lowest $CH_4$-producing feeds were corn gluten feed, brewer's grain, and orchard grass among the energy, protein, and forage feed groups, respectively. Significant differences (p<0.05) were found in digestibility, soluble total organic carbon (TOCs), and $CH_4$ emissions among feeds, during 48 h of in vitro fermentation. Digestibility and TOCs was not found to be related due to different fermentation pattern of each but TOCs production was directly proportional to $CH_4$ production (y = 0.0076x, $r^2$ = 0.83). From this in vitro study, TOCs production could be used as an indirect index for estimation of $CH_4$ emission from feed ingredients.

Field Application of Biocovers in Landfills for Methane Mitigation (매립지 메탄 저감을 위한 바이오커버의 현장 적용 평가)

  • Jung, Hyekyeng;Yun, Jeonghee;Oh, Kyung Cheol;Jeon, Jun-Min;Ryu, Hee-Wook;Cho, Kyung-Suk
    • Microbiology and Biotechnology Letters
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    • v.45 no.4
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    • pp.322-329
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    • 2017
  • Two pilot-scale biocovers (PBCs) were installed in a landfill, and the methane ($CH_4$) concentrations at their inlets and outlets were monitored for 240 days to evaluate the methane removability. Consequently, the packing materials were sampled from the PBCs, and their potential $CH_4$ oxidizing abilities were evaluated in serum vials. The $CH_4$ concentration at the inlet of the biocovers was observed to be in the range of 23.7-47.9% (average = 41.3%, median = 42.6%). In PBC1, where a mixture of soil, earthworm cast, and compost (7:2:1, v/v) was employed as the packing material, the $CH_4$ removal efficiency was evaluated to be between 60.7-85.5%. In PBC2, which was filled with a mixture of soil, earthworm cast, perlite, and compost (4:2:3:1, v/v), the removal efficiency was evaluated to be between 29.2-78.5%. Although the packing materials had an excellent $CH_4$ oxidizing potential (average oxidation rate for $CH_4=180-199{\mu}g\;CH_4{\cdot}g\;packing\;material^{-1}{\cdot}h^{-1}$), $CH_4$ removal efficiency in PBC1 and PBC2 decreased to the range of 0-30% once the packing materials in the PBCs were clogged and channeled. Furthermore, seasonal effects exhibited no significant differences in the $CH_4$ removal efficiency of the biocovers. The results of this study can be used to design and operate real-scale biocovers in landfills to mitigate $CH_4$ buildup.

Influence of Ni/CeO2-ZrO2 Catalysts on Methane Autothermal Reforming (메탄 자열개질 반응에 대한 Ni/CeO2-ZrO2 촉매의 영향)

  • Kang, Min Goo;Lee, Tae Jun;Lee, Jong Dae
    • Korean Chemical Engineering Research
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    • v.47 no.1
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    • pp.17-23
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    • 2009
  • The catalytic behavior of $Ni/Ce_XZr_{(1-X)}O_2$ loaded on the alumina coated honeycomb monolith was studied for the autothermal reforming reaction of methane. Among the catalysts with the different Ce/Zr ratios, the $Ni/Ce_{0.80}Zr_{0.20}O_2$ Catalyst showed the highest conversion of methane. By investigating the effect of Ni content on the $Ni/Ce_{0.80}Zr_{0.20}O_2$ catalysts, the catalyst loaded with 15wt% Ni had the highest activity. Also, $H_2$ yield was increased as $H_2O/CH_4$ ratio increased. Methane conversion was improved as $O_2/CH_4$ ratio was increased, whereas the yield of $H_2$ was decreased. Among the catalysts tested for 30 hours, $Ni(15wt%)/Ce_{0.80}Zr_{0.20}O_2$ showed the excellent conversion(${\geq}99%$) of methane and the stability at the condition of $GHSV=30,000h^{-1}$, feed ratio S/C/O=2/1/0.5 and reaction temperature $800^{\circ}C$.

Relationship between the Methane Production and the CNCPS Carbohydrate Fractions of Rations with Various Concentrate/roughage Ratios Evaluated Using In vitro Incubation Technique

  • Dong, Ruilan;Zhao, Guangyong
    • Asian-Australasian Journal of Animal Sciences
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    • v.26 no.12
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    • pp.1708-1716
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    • 2013
  • The objective of the trial was to study the relationship between the methane ($CH_4$) production and the Cornell Net Carbohydrate and Protein System (CNCPS) carbohydrate fractions of feeds for cattle and the suitability of CNCPS carbohydrate fractions as the dietary variables in modeling the $CH_4$ production in rumen fermentation. Forty-five rations for cattle with the concentrate/roughage ratios of 10:90, 20:80, 30:70, 40:60, and 50:50 were formulated as feed samples. The Menke and Steingass's gas test was used for the measurement of $CH_4$ production. The feed samples were incubated for 48 h and the $CH_4$ production was analyzed using gas chromatography. Statistical analysis indicated that the $CH_4$ production (mL) was closely correlated with the CNCPS carbohydrate fractions (g), i.e. CA (sugars); $CB_1$ (starch and pectin); $CB_2$ (available cell wall) in a multiple linear pattern: $CH_4=(89.16{\pm}14.93)$ $CA+(124.10{\pm}13.90)$ $CB_1+(30.58{\pm}11.72)$ $CB_2+(3.28{\pm}7.19)$, $R^2=0.81$, p<0.0001, n = 45. Validation of the model using 10 rations indicated that the $CH_4$ production of the rations for cattle could accurately be predicted based on the CNCPS carbohydrate fractions. The trial indicated that the CNCPS carbohydrate fractions CA, $CB_1$ and $CB_2$ were suitable dietary variables for predicting the $CH_4$ production in rumen fermentation in vitro.

Prediction of methane emission from sheep based on data measured in vivo from open-circuit respiratory studies

  • Ma, Tao;Deng, Kaidong;Diao, Qiyu
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.9
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    • pp.1389-1396
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    • 2019
  • Objective: The current study analysed the relationships between methane ($CH_4$) output from animal and dietary factors. Methods: The dataset was obtained from 159 Dorper${\times}$thin-tailed Han lambs from our seven studies, and $CH_4$ production and energy metabolism data were measured in vivo by an opencircuit respiratory method. All lambs were confined indoors and fed pelleted diet during the whole experimental period in all studies. Data from two-thirds of lambs were used to develop linear and multiple regressions to describe the relationship between $CH_4$ emission and dietary variables, and data from the remaining one third of lambs were used to validate the established models. Results: $CH_4$ emission (g/d) was positively related to dry matter intake (DMI) and gross energy intake (GEI) (p<0.001). $CH_4$ energy/GEI was negatively related to metabolizable energy/gross energy and metabolizable energy/digestible energy (p<0.001). Using DMI to predict $CH_4$ emission (g/d) resulted in a coefficient of determination ($R^2$) of 0.80. Using GEI, digestible energy intake, and metabolizable energy intake predict $CH_4$ energy/GEI resulted in a $R^2$ of 0.92. Conclusion: the prediction equations established in the current study are useful to develop appropriate feeding and management strategies to mitigate $CH_4$ emissions from sheep.

A Numerical Study on Methane-Air Counterflow Diffusion Flames Part 2. Global Strain Rate

  • Park, Woe Chul
    • International Journal of Safety
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    • v.2 no.1
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    • pp.12-16
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    • 2003
  • In Part 1, the flame structure of the counterflow nonpremixed flames computed by using Fire Dynamics Simulator was compared with that of OPPDIF for different concentrations of methane in the fuel stream. In this study, comparisons were made for the global strain rate that is an important parameter for diffusion flames for further evaluation of FDS. At each of the three fuel concentrations, $20% CH_4+ 80% N_2, 50% CH_4 + 50% N_2, 90% CH_4 + 10% N_2$ in the fuel stream, the temperature and axial velocity profiles were investigated for the global strain rate in the range from 20 to $100s^{-1}$. Changes in flame thickness and radius were also compared with OPPDIF. There was good agreement in the temperature and axial velocity profiles between the axisymmetric simulations and the one-dimensional computations except for the regions where the flame temperature reach its peak and the axial velocity rapidly changes. The simulations of the axisymmetric flames with FDS showed that the flame thickness decreases and the flame radius increases with increasing global strain rate.