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Subject = methane;
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Displaying Results 1 - 25 of 40 on page 1 of 2
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A comprehensive experimental and simulation study of ignition delay time characteristics of single fuel C1–C2 hydrocarbons over a wide range of temperatures, pressures, equivalence ratios, and dilutions
(2021)
Baigmohammadi, Mohammadreza; Patel, Vaibhav; Martinez, Sergio; Panigrahy, Snehasish; Ra...
A comprehensive experimental and simulation study of ignition delay time characteristics of single fuel C1–C2 hydrocarbons over a wide range of temperatures, pressures, equivalence ratios, and dilutions
(2021)
Baigmohammadi, Mohammadreza; Patel, Vaibhav; Martinez, Sergio; Panigrahy, Snehasish; Ramalingam, Ajoy; Burke, Ultan; Somers, Kieran P.; Heufer, Karl A.; Pekalski, Andrzej; Curran, Henry J.
Abstract:
A comprehensive experimental and modeling study of the ignition delay time (IDT) characteristics of some single prominent C1–C2 hydrocarbons including methane, ethane, and ethylene has been performed over a wide range of temperatures (∼800–2000 K), pressures (∼1–80 bar), equivalence ratios (∼0.5–2.0), and dilutions (∼75–90%). An extensive literature review was conducted, and available data were extracted to create a comprehensive database used in our simulations. Based on existing literature data, an experimental matrix was designed using the Taguchi approach (L9) in order to identify and complete the experimental matrix required to generate a comprehensive validation set necessary for validation of a chemical kinetic model. The required IDTs were recorded using a high-pressure shock tube for shorter IDTs and a rapid compression machine for longer times, which encompass high- and low-temperature ranges, respectively. The predictions of a C3-NUIG mechanism have been compared with all...
http://hdl.handle.net/10379/16490
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A spatial micro-simulation analysis of methane emissions from irish agriculture
(2018)
Hynes, Stephen; Morrissey, Karyn; O’Donoghue, Cathal; Clarke, Graham
A spatial micro-simulation analysis of methane emissions from irish agriculture
(2018)
Hynes, Stephen; Morrissey, Karyn; O’Donoghue, Cathal; Clarke, Graham
http://hdl.handle.net/10379/12031
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An embodied carbon and embodied energy appraisal of a section of Irish motorway constructed in peatlands
(2017)
Duggan, Alan R.; McCabe, Bryan A.; Goggins, Jamie; Clifford, Eoghan
An embodied carbon and embodied energy appraisal of a section of Irish motorway constructed in peatlands
(2017)
Duggan, Alan R.; McCabe, Bryan A.; Goggins, Jamie; Clifford, Eoghan
Abstract:
In addition to the customary drivers of cost and timely project delivery, embodied energy (EE) and embodied carbon (EC) have come to prominence in recent years as major design considerations in all aspects of large-scale road construction projects. An assessment of road construction necessitating the excavation or alteration of peat should consider the impact on carbon stored within the peat and the greenhouse gases potentially released. A methodology for calculating the environmental impact of constructing roads on peat is presented in this paper. Furthermore, the paper describes the application of this methodology (focusing on EE and EC calculations) to a case study; a section of the M6 motorway in Ireland for which excavate-and-replace was the ground improvement method (Scenario ER). A range of peat-related factors impacting on EE and EC estimates were examined, including materials, transport and machinery, as well as more unfamiliar factors such as peat drainage, drainage system...
http://hdl.handle.net/10379/6302
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An experimental and chemical kinetic modeling study of 1,3-butadiene combustion: Ignition delay time and laminar flame speed measurements
(2019)
Zhou, Chong-Wen; Li, Yang; Burke, Ultan; Banyon, Colin; Somers, Kieran P.; Ding, Shuiti...
An experimental and chemical kinetic modeling study of 1,3-butadiene combustion: Ignition delay time and laminar flame speed measurements
(2019)
Zhou, Chong-Wen; Li, Yang; Burke, Ultan; Banyon, Colin; Somers, Kieran P.; Ding, Shuiting; Khan, Saadat; Hargis, Joshua W.; Sikes, Travis; Mathieu, Olivier; Petersen, Eric L.; AlAbbad, Mohammed; Farooq, Aamir; Pan, Youshun; Zhang, Yingjia; Huang, Zuohua; Lopez, Joseph; Loparo, Zachary; Vasu, Subith S.; Curran, Henry J.
Abstract:
Ignition delay times for 1,3-butadiene oxidation were measured in five different shock tubes and in a rapid compression machine (RCM) at thermodynamic conditions relevant to practical combustors. The ignition delay times were measured at equivalence ratios of 0.5, 1.0, and 2.0 in 'air' at pressures of 10, 20 and 40 atm in both the shock tubes and in the RCM. Additional measurements were made at equivalence ratios of 0.3, 0.5, 1.0 and 2.0 in argon, at pressures of 1, 2 and 4 atm in a number of different shock tubes. Laminar flame speeds were measured at unburnt temperatures of 295 K, 359 K and 399 K at atmospheric pressure in the equivalence ratio range of 0.6-1.7, and at a pressure of 5 atm at equivalence ratios in the range 0.6-1.4. These experimental data were then used as validation targets for a newly developed detailed chemical kinetic mechanism for 1,3-butadiene oxidation.A detailed chemical kinetic mechanism (AramcoMech 3.0) has been developed to describe the combus...
http://hdl.handle.net/10379/14784
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An experimental and modeling study of propene oxidation. part 2: ignition delay time and flame speed measurements
(2018)
Burke, Sinéad M.; Burke, Ultan; Mc Donagh, Reuben; Mathieu, Olivier; Osorio, Irmis; Kee...
An experimental and modeling study of propene oxidation. part 2: ignition delay time and flame speed measurements
(2018)
Burke, Sinéad M.; Burke, Ultan; Mc Donagh, Reuben; Mathieu, Olivier; Osorio, Irmis; Keesee, Charles; Morones, Anibal; Petersen, Eric L.; Wang, Weijing; DeVerter, Trent A.; Oehlschlaeger, Matthew A.; Rhodes, Brandie; Hanson, Ronald K.; Davidson, David F.; Weber, Bryan W.; Sung, Chih-Jen; Santner, Jeffrey; Ju, Yiguang; Haas, Francis M.; Dryer, Frederick L.
http://hdl.handle.net/10379/10608
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An ignition delay and kinetic modeling study of methane, dimethyl ether, and their mixtures at high pressures
(2016)
Burke, Ultan; Somers, Kieran P.; O’Toole, Peter; Zinner, Chis M.; Marquet, Nicolas; Bou...
An ignition delay and kinetic modeling study of methane, dimethyl ether, and their mixtures at high pressures
(2016)
Burke, Ultan; Somers, Kieran P.; O’Toole, Peter; Zinner, Chis M.; Marquet, Nicolas; Bourque, Gilles; Petersen, Eric L.; Metcalfe, Wayne K.; Serinyel, Zeynep; Curran, Henry J.
Abstract:
Journal article
The development of accurate chemical kinetic models capable of predicting the combustion of methane and dimethyl ether in common combustion environments such as compression ignition engines and gas turbines is important as it provides valuable data and understanding of these fuels under conditions that are difficult and expensive to study in the real combustors. In this work, both experimental and chemical kinetic model-predicted ignition delay time data are provided covering a range of conditions relevant to gas turbine environments (T = 600-1600 K, p = 7-41 atm, phi = 0.3, 0.5, 1.0, and 2.0 in 'air' mixtures). The detailed chemical kinetic model (Mech_56.54) is capable of accurately predicting this wide range of data, and it is the first mechanism to incorporate high-level rate constant measurements and calculations where available for the reactions of DME. This mechanism is also the first to apply a pressure-dependent treatment to the low-temperature...
http://hdl.handle.net/10379/6102
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An ignition delay time and chemical kinetic modeling study of the pentane isomers
(2016)
Bugler, John; Heufer, Karl A.; Curran, Henry J.
An ignition delay time and chemical kinetic modeling study of the pentane isomers
(2016)
Bugler, John; Heufer, Karl A.; Curran, Henry J.
Abstract:
Ignition delay times of n-pentane, iso-pentane, and neo-pentane mixtures were measured in two shock tubes and in a rapid compression machine. The experimental data were used as validation targets for the model described in detail in an accompanying study [14]. The present study presents ignition delay time data for the pentane isomers at equivalence ratios of 0.5, 1.0, and 2.0 in 'air' (additionally, 0.3 in 'air' for n-, and isopentane) at pressures of 1, 10, and 20 atm in the shock tube, and 10 and 20 atm in the rapid compression machine, as well as data at an equivalence ratio of 1.0 in 99% argon, at pressures near 1 and 10 atm in a shock tube. An infrared laser absorption technique at 3.39 mu m was used to verify the composition of the richest mixtures in the shock-tube tests by measuring directly the pentane isomer concentration in the driven section. By using shock tubes and a rapid compression machine, it was possible to investigate temperatures ranging fro...
http://hdl.handle.net/10379/5640
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An ignition delay time and chemical kinetic modeling study of the pentane isomers
(2018)
Bugler, John; Marks, Brandon; Mathieu, Olivier; Archuleta, Rachel; Camou, Alejandro; Gr...
An ignition delay time and chemical kinetic modeling study of the pentane isomers
(2018)
Bugler, John; Marks, Brandon; Mathieu, Olivier; Archuleta, Rachel; Camou, Alejandro; Grégoire, Claire; Heufer, Karl A.; Petersen, Eric L.; Curran, Henry J.
http://hdl.handle.net/10379/10589
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An RCM experimental and modeling study on CH4 and CH4/C2H6 oxidation at pressures up to 160 bar
(2017)
Ramalingam, Ajoy; Zhang, Kuiwen; Dhongde, Avnish; Virnich, Lukas; Sankhla, Harsh; Curra...
An RCM experimental and modeling study on CH4 and CH4/C2H6 oxidation at pressures up to 160 bar
(2017)
Ramalingam, Ajoy; Zhang, Kuiwen; Dhongde, Avnish; Virnich, Lukas; Sankhla, Harsh; Curran, Henry J.; Heufer, Alexander
Abstract:
The oxidation of CH4 and CH4/C2H6 mixtures were studied at pressures relevant to knocking in large bore natural gas engines. The experiments were carried out in a rapid compression machine (RCM) at end of compression (EOC) temperatures ranging between 885 and 940 K at compressed gas pressures of 105, 125, 150, and 160 bar at varying equivalence ratios (0.417, 0.526, and 1.0) and dilution percentages (0, 10, and 30% Exhaust Gas Recirculation - EGR) that were defined in a test matrix. This study describes the method and limitations of performing high-pressure experiments of this magnitude in an RCM, modeling, and validation of the kinetic mechanism against experimental data. While the recently published AramcoMech 2.0 could well predict the ignition delay times (IDTs) for CH4 within the uncertainty ranges at comparatively higher pressures and lower temperatures (885-940 K), the predicted reactivity is, in general, lower than that of AramcoMech 1.3 as shown in our previous screening st...
http://hdl.handle.net/10379/6899
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Application of Meta-Analysis and Machine Learning Methods to the Prediction of Methane Production from In Vitro Mixed Ruminal Micro-Organism Fermentation
(2020)
Ellis, Jennifer L.; Alaiz-Moretón, Héctor; Navarro-Villa, Alberto; McGeough, Emma J.; P...
Application of Meta-Analysis and Machine Learning Methods to the Prediction of Methane Production from In Vitro Mixed Ruminal Micro-Organism Fermentation
(2020)
Ellis, Jennifer L.; Alaiz-Moretón, Héctor; Navarro-Villa, Alberto; McGeough, Emma J.; Purcell, Peter; Powell, Christopher D.; O’Kiely, Padraig; France, James; López, Secundino
Abstract:
In vitro gas production systems are utilized to screen feed ingredients for inclusion in ruminant diets. However, not all in vitro systems are set up to measure methane (CH4) production, nor do all publications report in vitro CH4. Therefore, the objective of this study was to develop models to predict in vitro CH4 production from total gas and volatile fatty acid (VFA) production data and to identify the major drivers of CH4 production in these systems. Meta-analysis and machine learning (ML) methodologies were applied to a database of 354 data points from 11 studies to predict CH4 production from total gas production, apparent DM digestibility (DMD), final pH, feed type (forage or concentrate), and acetate, propionate, butyrate and valerate production. Model evaluation was performed on an internal dataset of 107 data points. Meta-analysis results indicate that equations containing DMD, total VFA production, propionate, feed type and valerate resulted in best predictability of CH4 ...
http://hdl.handle.net/11019/2190
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Assessment of continuous fermentative hydrogen and methane co-production using macro- and micro-algae with increasing organic loading rate
(2018)
Ding, Lingkan; Chan Gutierrez, Enrique; Cheng, Jun; Xia, Ao; O'Shea, Richard; Gune...
Assessment of continuous fermentative hydrogen and methane co-production using macro- and micro-algae with increasing organic loading rate
(2018)
Ding, Lingkan; Chan Gutierrez, Enrique; Cheng, Jun; Xia, Ao; O'Shea, Richard; Guneratnam, Amita Jacob; Murphy, Jerry D.
Abstract:
A two-stage continuous fermentative hydrogen and methane co-production using macro-algae (Laminaria digitata) and micro-algae (Arthrospira platensis) at a C/N ratio of 20 was established. The hydraulic retention time (HRT) of first-stage H2 reactor was 4 days. The highest specific hydrogen yield of 55.3 mL/g volatile solids (VS) was obtained at an organic loading rate (OLR) of 6.0 gVS/L/d. In the second-stage CH4 reactor at a short HRT of 12 days, a specific methane yield of 245.0 mL/gVS was achieved at a corresponding OLR of 2.0 gVS/L/d. At these loading rates, the two-stage continuous system offered process stability and effected an energy yield of 9.4 kJ/gVS, equivalent to 77.7% of that in an idealised batch system. However, further increases in OLR led to reduced hydrogen and methane yields in both reactors. The process was compared to a one-stage anaerobic co-digestion of algal mixtures at an HRT of 16 days. A remarkably high salinity level of 13.3 g/kg was recorded and volatil...
http://hdl.handle.net/10468/5730
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Benefits and Costs of Methane Emission Reduction in the Irish National Herd
(2010)
Garvey, Eoghan; Mc Inerney, Niall
Benefits and Costs of Methane Emission Reduction in the Irish National Herd
(2010)
Garvey, Eoghan; Mc Inerney, Niall
Abstract:
In this paper, we compare many of the widely available estimated global benefits of abatement with the costs to Irish agriculture, as estimated by the CAPRI model. We apply the model to Ireland only, in a simple comparative static simulation, and assume fixed prices. We focus more on methane reduction than GWP reduction as a whole, because most of the discussion regarding global warming from agriculture in Ireland has focused on methane. Our results suggest that the costs of methane abatement to the farming sector do indeed outweigh the global benefits, except in the case of very small methane abatements. However, if one also factors in the gains to society of the FEOGA budget rebates, then all losses disappear, and in fact net financial gains occur. We conclude that this may have implications for the design of methane reduction policies.
http://hdl.handle.net/10379/988
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Biological hydrogen methanation systems–an overview of design and efficiency
(2019)
Rusmanis, Davis; O'Shea, Richard; Wall, David M.; Murphy, Jerry D.
Biological hydrogen methanation systems–an overview of design and efficiency
(2019)
Rusmanis, Davis; O'Shea, Richard; Wall, David M.; Murphy, Jerry D.
Abstract:
The rise in intermittent renewable electricity production presents a global requirement for energy storage. Biological hydrogen methanation (BHM) facilitates wind and solar energy through the storage of otherwise curtailed or constrained electricity in the form of the gaseous energy vector biomethane. Biological methanation in the circular economy involves the reaction of hydrogen – produced during electrolysis – with carbon dioxide in biogas to produce methane (4H2 + CO2 = CH4 + 2H2), typically increasing the methane output of the biogas system by 70%. In this paper, several BHM systems were researched and a compilation of such systems was synthesized, facilitating comparison of key parameters such as methane evolution rate (MER) and retention time. Increased retention times were suggested to be related to less efficient systems with long travel paths for gases through reactors. A significant lack of information on gas-liquid transfer co-efficient was identified.
http://hdl.handle.net/10468/9331
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Carbon mitigation in the dry reforming of methane
(2020)
Aramouni, Nicolas Abdel Karim
Carbon mitigation in the dry reforming of methane
(2020)
Aramouni, Nicolas Abdel Karim
Abstract:
Dry reforming of methane is a technique to produce syngas from biogas or CO2-rich natural gas at high temperatures, generally over a Ni or Co catalyst. Syngas produced by dry reforming has a H2/CO ratio around 1, which makes it CO-rich, and therefore suitable for the production of pure CO or Gas-to-Liquid processes. Up to date, large-scale application of dry reforming has been limited, with the main barriers to industrial deployment being the highly endothermic reaction pathway that requires high operating temperatures to reach acceptable conversion levels in the presence of alumina-supported nickel catalysts and the formation of high-strength carbon whiskers catalysed by nickel crystallites, which are destructive to catalyst pellets. A thermodynamic analysis of the reaction pathway is first performed while relaxing the conventional assumption that graphite is the phase of carbon that forms. The effect of catalyst dispersion and the precursors to coking are identified, and the effec...
http://hdl.handle.net/10344/9574
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Comparisons of continuous atmospheric CH4, CO2 and N2O measurements – results from a travelling instrument campaign at Mace Head
(2018)
Vardag, S. N.; Hammer, S.; O'Doherty, S.; Spain, T. G.; Wastine, B.; Jordan, A.; L...
Comparisons of continuous atmospheric CH4, CO2 and N2O measurements – results from a travelling instrument campaign at Mace Head
(2018)
Vardag, S. N.; Hammer, S.; O'Doherty, S.; Spain, T. G.; Wastine, B.; Jordan, A.; Levin, I.
Abstract:
A 2-month measurement campaign with a Fourier transform infrared analyser as a travelling comparison instrument (TCI) was performed at the Advanced Global Atmospheric Gases Experiment (AGAGE) and World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) station at Mace Head, Ireland. The aim was to evaluate the compatibility of atmospheric methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O) measurements of the routine station instrumentation, consisting of a gas chromatograph (GC) for CH4 and N2O as well as a cavity ring-down spectroscopy (CRDS) system for CH4 and CO2. The advantage of a TCI approach for quality control is that the comparison covers the entire ambient air measurement system, including the sample intake system and the data evaluation process. For initial quality and performance control, the TCI was run in parallel with the Heidelberg GC before and after the measurement campaign at Mace Head. Median differences between the Heidelberg GC and the TCI...
http://hdl.handle.net/10379/14273
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Comprehensive experimental and simulation study of the ignition delay time characteristics of binary blended methane, ethane, and ethylene over a wide range of temperature, pressure, equivalence ratio, and dilution
(2021)
Baigmohammadi, Mohammadreza; Patel, Vaibhav; Nagaraja, Shashank; Ramalingam, Ajoy; Mart...
Comprehensive experimental and simulation study of the ignition delay time characteristics of binary blended methane, ethane, and ethylene over a wide range of temperature, pressure, equivalence ratio, and dilution
(2021)
Baigmohammadi, Mohammadreza; Patel, Vaibhav; Nagaraja, Shashank; Ramalingam, Ajoy; Martinez, Sergio; Panigrahy, Snehasish; Mohamed, Ahmed Abd El-Sabor; Somers, Kieran P.; Burke, Ultan; Heufer, Karl A.; Pekalski, Andrzej; Curran, Henry J.
Abstract:
A comprehensive experimental and kinetic modeling study of the ignition delay time (IDT) characteristics of some binary blends of C1–C2 gaseous hydrocarbons such as methane/ethylene, methane/ethane, and ethane/ethylene was performed over a wide range of composition (90/10, 70/30, 50/50%), temperature (∼800–2000 K), pressure (∼1–40 bar), equivalence ratio (∼0.5–2.0), and dilution (∼75–90%). An extensive literature review was conducted, and available data were extracted to create a comprehensive database for our simulations. Based on the existing literature data, an experimental matrix was designed using the Taguchi approach (L9) in order to identify and complete the experimental matrix required to generate a comprehensive experimental IDT set necessary for the validation of a chemical kinetic model. The required high- and low-temperature IDTs were collected using low-/high-pressure shock tubes and rapid compression machines, respectively. The predictions of NUIGMech1.0 are examined v...
http://hdl.handle.net/10379/16489
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Copper/molybdenum nanocomposite particles as catalysts for the growth of bamboo-structured carbon nanotubes
(2008)
Li, Zhonglai; Larsson, J. Andreas; Larsson, Peter; Ahuja, Rajeev; Tobin, Joseph M.; O...
Copper/molybdenum nanocomposite particles as catalysts for the growth of bamboo-structured carbon nanotubes
(2008)
Li, Zhonglai; Larsson, J. Andreas; Larsson, Peter; Ahuja, Rajeev; Tobin, Joseph M.; O'Byrne, Justin; Morris, Michael A.; Attard, Gary; Holmes, Justin D.
Abstract:
Bamboo-structured carbon nanotubes (BCNTs), with mean diameters of 20 nm, have been synthesized on MgO-supported Cu and Mo catalysts by the catalytic chemical vapor deposition of methane. BCNTs could only be generated using a combination of Cu and Mo catalysts. No BCNTs were produced from either individual Cu or Mo catalysts. In combination, Mo was found to be essential for cracking the methane precursor, while Cu was required for BCNT formation. Energy dispersive X-ray analysis of the individual particles at the tips of the nanotubes suggest that Cu and Mo are present as a “composite” nanoparticle catalyst after growth. First-principles modeling has been used to describe the interaction of the Cu/Mo catalyst with the nanotubes, suggesting that the catalyst binds with the same energy as traditional catalysts such as Fe, Ni, and Co.
http://hdl.handle.net/10468/8149
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Effect of sulfate on low-temperature anaerobic digestion
(2019)
Madden, Pádhraig; Al-Raei, Abdul M.; Enright, Anne M.; Chinalia, Fabio A.; de Beer, Dir...
Effect of sulfate on low-temperature anaerobic digestion
(2019)
Madden, Pádhraig; Al-Raei, Abdul M.; Enright, Anne M.; Chinalia, Fabio A.; de Beer, Dirk; O'Flaherty, Vincent; Collins, Gavin
Abstract:
The effect of sulfate addition on the stability of, and microbial community behavior in, low-temperature anaerobic expanded granular sludge bed-based bioreactors was investigated at 15 degrees C. Efficient bioreactor performance was observed, with chemical oxygen demand (COD) removal efficiencies of >90%, and a mean SO42- removal rate of 98.3%. In situ methanogensis appeared unaffected at a COD: SO42- influent ratio of 8:1, and subsequently of 3:1, and was impacted marginally only when the COD: SO42- ratio was 1:2. Specific methanogenic activity assays indicated a complex set of interactions between sulfate-reducing bacteria (SRB), methanogens and homoacetogenic bacteria. SO42- addition resulted in predominantly acetoclastic, rather than hydrogenotrophic, methanogenesis until >600 days of SO42--influenced bioreactor operation. Temporal microbial community development was monitored by denaturation gradient gel electrophoresis (DGGE) of 16S rRNA genes. Fluorescence in situ hybri...
http://hdl.handle.net/10379/15424
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Effects of fertiliser nitrogen rate to spring grass on apparent digestibility, nitrogen balance, ruminal fermentation and microbial nitrogen production in beef cattle and in vitro rumen fermentation and methane output
(2019)
O'Connor, Alan; Moloney, Aidan P; O'Kiely, Padraig; Boland, T. M.; McGee, Mark
Effects of fertiliser nitrogen rate to spring grass on apparent digestibility, nitrogen balance, ruminal fermentation and microbial nitrogen production in beef cattle and in vitro rumen fermentation and methane output
(2019)
O'Connor, Alan; Moloney, Aidan P; O'Kiely, Padraig; Boland, T. M.; McGee, Mark
Abstract:
The effects of two fertiliser nitrogen (N) application rates - 15 (LN) or 80 (HN) kg N/ha - to Lolium perenne dominant swards in spring, on grass dry matter (DM) intake, digestion, rumen fermentation, microbial N production and N-balance in beef cattle, and in vitro fermentation and methane production were studied. Sixteen Charolais steers with a mean live weight (s.d.) of 475 (18.4) kg, were used in a completely randomised block design experiment and offered zero-grazed grass harvested 21-d post N application. The same grass was incubated in an eight-vessel RUSITEC in a completely randomised block design experiment. The HN treatment had a 540 kg/ha higher grass DM yield, and a 20 g/kg DM higher crude protein (CP) concentration compared to LN. There was no difference (P > 0.05) in DM intake, or in vivo DM, organic matter (OM) and N digestibility between treatments. Rumen fermentation variables pH, lactic acid, ammonia (NH3) and total volatile fatty acid (VFA) concentration were s...
http://hdl.handle.net/11019/1800
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Enhanced catalytic activity of Ni on η-Al2O3 and ZSM-5 on addition of ceria zirconia for the partial oxidation of methane
(2017)
Osman, Ahmed I.; Meudal, Jonathan; Laffir, Fathima R.; Thompson, Jillian; Rooney, David
Enhanced catalytic activity of Ni on η-Al2O3 and ZSM-5 on addition of ceria zirconia for the partial oxidation of methane
(2017)
Osman, Ahmed I.; Meudal, Jonathan; Laffir, Fathima R.; Thompson, Jillian; Rooney, David
Abstract:
Nickel supported on η-Al2O3 and ZSM-5(80) catalysts with and without the addition of ceria-zirconia, were prepared by co-precipitation and wet impregnation methods and used for the low temperature catalytic partial oxidation of methane (CPOM). The catalysts were tested under reaction temperatures of between 400 and 700 °C with a WHSV of 63,000 mL g−1 h−1. The activity of the catalyst was found to be dependent on the support and preparation method. The optimum catalyst composition of those tested was 10% Ni on 25%CeO2-ZrO2/ZSM-5(80), prepared by co-precipitation, where the reaction reached equilibrium conversion at 400 °C (T50% < 400 °C), which is one of the lowest temperatures reported to date. Further increases in temperature led to improved selectivity to CO reaching 60% at 600 °C. Although the observed kinetics were found to be controlled by strong adsorption of CO at lower temperature, this was an equilibrium limitation with longer time on stream experiments showing no decrea...
http://hdl.handle.net/10344/6612
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European greenhouse gas emissions estimated from continuous atmospheric measurements and radon 222 at mace head, ireland
(2018)
Biraud, Sébastien; Ciais, Philippe; Ramonet, Michel; Simmonds, Peter; Kazan, Victor; Mo...
European greenhouse gas emissions estimated from continuous atmospheric measurements and radon 222 at mace head, ireland
(2018)
Biraud, Sébastien; Ciais, Philippe; Ramonet, Michel; Simmonds, Peter; Kazan, Victor; Monfray, Patrick; O'Doherty, Simon; Spain, T. Gerard; Jennings, S. Gerard
Abstract:
Flux estimates of CO2, CH4 N2O, and CFCs over western Europe have been inferred from continuous atmospheric records of these species at the atmospheric research 771 station of Mace Head, Ireland. We use radon ( Rn) which has a fairly uniform source over continents as a reference compound to estimate unknown sources of other species. The Rn-222 is calculated for a suite of synoptic events that correlation between each species and have been selected in the Mace Head record over the period 1996/97. In the following, we describe the method and its uncertainties, and we establish data selection criteria that minimize the influence of local sources over Ireland, in the vicinity of the station, in order to select synoptic events originating from western Europe. We estimate western European flux densities of 45-30 10(3) kg C km(-2) month(-1) during wintertime for CO2, of 4.8-3.5 10(3) kg CH4 km(-2) yr(-1), 475-330 kg N2O km(-2) yr(-1) 2.5-1.8 kg CFC-11 km(-2) yr(-1) for CFC-11 and 4.2-2.9 k...
http://hdl.handle.net/10379/8876
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Factors controlling headspace pressure in a manual manometric BMP method can be used to produce a methane output comparable to AMPTS
(2017)
Himanshu, Himanshu; Voelklein, Markus A.; Murphy, Jerry D.; Grant, J.; O'Kiely, Pa...
Factors controlling headspace pressure in a manual manometric BMP method can be used to produce a methane output comparable to AMPTS
(2017)
Himanshu, Himanshu; Voelklein, Markus A.; Murphy, Jerry D.; Grant, J.; O'Kiely, Padraig
Abstract:
The manual manometric biochemical methane potential (mBMP) test uses the increase in pressure to calculate the gas produced. This gas production may be affected by the headspace volume in the incubation bottle and by the overhead pressure measurement and release (OHPMR) frequency. The biogas and methane yields of cellulose, barley, silage and slurry were compared with three incubation bottle headspace volumes (50, 90 and 180ml; constant 70ml total medium) and four OHPMR frequencies (daily, each third day, weekly and solely at the end of experiment). The methane yields of barley, silage and slurry were compared with those from an automated volumetric method (AMPTS). Headspace volume and OHPMR frequency effects on biogas yield were mediated mainly through headspace pressure, with the latter having a negative effect on the biogas yield measured and relatively little effect on methane yield. Two mBMP treatments produced methane yields equivalent to AMPTS.
http://hdl.handle.net/10468/4549
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Greenhouse gas emissions from two rewetted peatlands previously managed for forestry
(2018)
Rigney, Caitlin; Wilson, D.; Renou-Wilson, F.; Müller, C.; Moser, G.; Byrne, Kenneth A.
Greenhouse gas emissions from two rewetted peatlands previously managed for forestry
(2018)
Rigney, Caitlin; Wilson, D.; Renou-Wilson, F.; Müller, C.; Moser, G.; Byrne, Kenneth A.
Abstract:
The aim of this study was to investigate the controls on carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) dynamics on a blanket bog (at Pollagoona) and a raised bog (at Scohaboy) in Ireland after felling of plantation forestry and rewetting, and to produce annual balances for each gas at both sites. Gas fluxes were measured during a twelve-month period using the chamber method. Microsite types reflecting the dominant plant species at the chamber plots were identified and classified as Eriophorum-Sphagnum, Cladonia-Calluna and Molinia at Pollagoona and Eriophorum-Sphagnum, Cladonia-mosses, Eriophorum and brash (logging residues) at Scohaboy. The relationships between gas fluxes and environmental variables were assessed, and regression models were used to estimate annual CO2 and CH4 gas balances for each microsite type. Annual estimates of N2O exchange were calculated using seasonal means. Over the course of the study both sites acted as CO2 and CH4 sources. Although Pollag...
http://hdl.handle.net/10344/7489
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Greenhouse gas measurements from a uk network of tall towers: technical description and first results
(2018)
Stanley, Kieran M.; Grant, Aoife; O&apos;Doherty, Simon; Young, Dickon; Manning...
Greenhouse gas measurements from a uk network of tall towers: technical description and first results
(2018)
Stanley, Kieran M.; Grant, Aoife; O&apos;Doherty, Simon; Young, Dickon; Manning, Alistair J.; Stavert, Ann R.; Spain, T. Gerard; Salameh, Peter K.; Harth, Christina M.; Simmonds, Peter G.; Sturges, William T.; Oram, David E.; Derwent, Richard G.
Abstract:
A network of three tall tower measurement stations was set up in 2012 across the United Kingdom to expand measurements made at the long-term background northern hemispheric site, Mace Head, Ireland. Reliable and precise in situ greenhouse gas (GHG) analysis systems were developed and deployed at three sites in the UK with automated instrumentation measuring a suite of GHGs. The UK Deriving Emissions linked to Climate Change (UK DECC) network uses tall (165-230 m) open-lattice telecommunications towers, which provide a convenient platform for boundary layer trace gas sampling. In this paper we describe the automated measurement system and first results from the UK DECC network for CO2, CH4, N2O, SF6, CO and H-2. CO2 and CH4 are measured at all of the UK DECC sites by cavity ring-down spectroscopy (CRDS) with multiple inlet heights at two of the three tall tower sites to assess for boundary layer stratification. The short-term precisions (1 sigma on 1 min means) of CRDS measurements a...
http://hdl.handle.net/10379/14005
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Growth of carbon nanotubes from heterometallic palladium and copper catalysts
(2010)
O'Byrne, Justin P.; Li, Zhonglai; Tobin, Joseph M.; Larsson, J. Andreas; Larsson, ...
Growth of carbon nanotubes from heterometallic palladium and copper catalysts
(2010)
O'Byrne, Justin P.; Li, Zhonglai; Tobin, Joseph M.; Larsson, J. Andreas; Larsson, Peter; Ahuja, Rajeev; Holmes, Justin D.
Abstract:
Bamboo-structured carbon nanotubes (BCNTs) were synthesized with MgO-supported Pd and Cu catalysts, doped with either Mo or W, by the catalytic chemical vapor decomposition of methane. No nanotubes were observed to grow from the catalysts in the absence of the dopant metals. Additionally, the level of dopant in the catalysts was found to strongly affect the morphology of carbon produced. Amorphous carbon was generated on a 10 wt % Cu/5 wt % W (2:1) catalyst, while BCNTs were produced on 20 wt % Cu/5 wt % W (4:1) and a 30 wt % Cu/5 wt % W (6:1) catalysts. A pure Pd catalyst produced carbon nanofibres (CNFs), while BCNTs were able to grow from Pd/Mo catalysts. Density functional theory simulations show that the composite Cu/W and Pd/Mo bimetallic particles which generated BCNTs have similar binding energies to carbon, and comparable to metals such as Fe, Co, and Ni which are traditionally used to grow CNTs by chemical vapor deposition.
http://hdl.handle.net/10468/6647
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