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Subhasis Das, Manideepa Sengupta, Arijit Bag, Mumtaj Shah, Ankur Bordoloi
A synergistic approach was made to develop a highly stable and carbon resistant catalyst system based on cobalt and nickel supported over modified mesoporous silica for the dry reforming of methane (DRM). Modified mesoporous silica is prepared by a hydrothermal method, and the total Co & Ni composition is taken at around 5% by using the deposition-precipitation technique. CO2 reforming with methane was performed at 400-800 °C under atmospheric pressure as well as at a pressure of 1 MPa, keeping the CH4/CO2 ratio equal to unity...
March 21, 2018: Nanoscale
Chu K Yao, Asaf Rotbart, Jian Z Ou, Kourosh Kalantar-Zadeh, Jane G Muir, Peter R Gibson
Excessive hydrogen sulfide (H2 S) production from gut microbial metabolism may have clinically important relevance in the pathogenesis of gut disorders, including ulcerative colitis. However, little is known regarding factors that alter its production. Using a newly-designed in vitro gas-profiling technology, the study aimed to verify real-time H2 S measurement reproducibility and thereafter, assess its production following exposure to dietary factors and 5-aminosalicylate acid (5-ASA). Measurements of H2 S, carbon dioxide, hydrogen and methane measurements were compared between gas-profiling systems...
March 21, 2018: Gut Microbes
Surinder Pal Kaur, K S Sujith, C N Ramachandran
The replacement of methane (CH4) from its hydrate by a mixture of nitrogen (N2) and carbon dioxide (CO2) involves the dissociation of methane hydrate leading to the formation of a CH4-N2-CO2-H2O mixture that can significantly influence the subsequent steps of the replacement process. In the present work, we study the evolution of dissolved gas molecules in this mixture by applying classical molecular dynamics simulations. Our study shows that a higher CO2 : N2 ratio in the mixture enhances the formation of nanobubbles composed of N2, CH4 and CO2 molecules...
March 21, 2018: Physical Chemistry Chemical Physics: PCCP
Shiming Tang, Yujuan Zhang, Xiajie Zhai, Andreas Wilkes, Chengjie Wang, Kun Wang
BACKGROUND: The effects of grazing on soil methane (CH4 ) uptake in steppe ecosystems are important for understanding carbon sequestration and cycling because the role of grassland soil for CH4 uptake can have major impacts at the global level. Here, a meta-analysis of 27 individual studies was carried out to assess the response patterns of soil CH4 uptake to grazing in steppe ecosystems of China. The weighted log response ratio was used to assess the effect size. RESULTS: We found that heavy grazing significantly depressed soil CH4 uptake by 36...
March 20, 2018: BMC Ecology
Jérôme Long, Dimitry M Lyubov, Tatyana V Mahrova, Anton V Cherkasov, Georgy K Fukin, Yannick Guari, Joulia Larionova, Alexander A Trifonov
We report on the synthesis, structure and investigation of magnetic properties of a series of six heteroleptic complexes of the general formula [Ln(Tpm)X3]·yMeCN (Tpm = tris(3,5-dimethylpyrazolyl)methane; Ln = Tb, Dy, Er; X- = NO3-, Cl- and y = 1 or 2). We demonstrate that the observation of a field-induced slow relaxation of magnetization is highly dependent on the anion's nature. While nitrate moieties appear to be suitable to stabilize the oblate electronic density of Dy3+, chloride ions generate an equatorial crystal-field allowing the slow relaxation of the prolate Er3+ ions...
March 20, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
C Kaewpila, K Sommart, M Mitsumori
The mitigation of enteric methane emission in beef cattle production is important for reducing feed energy loss and increasing environmental sustainability. The main objective of this study was to evaluate the effect of different oilseeds included in fermented total mixed rations (whole soyabean seed (SBS, control), whole kapok seed (KPS) and cracked oil palm fruit (OPF)) on feed intake, digestibility, rumen microbial populations, energy partition and methane emissions in different cattle genotypes (Charolais crossbred v...
March 20, 2018: Animal: An International Journal of Animal Bioscience
Ian M Boothroyd, Sam Almond, Fred Worrall, Rosemary K Davies, Richard J Davies
Natural gas pipelines are an important source of fugitive methane emissions in lifecycle greenhouse gas assessments but limited monitoring has taken place of UK pipelines to quantify fugitive emissions. This study investigated methane emissions from the UK high-pressure pipeline system (National Transmission System - NTS) for natural gas pipelines. Mobile surveys of CH4 emissions were conducted across four areas in the UK, with routes bisecting high-pressure pipelines (with a maximum operating pressure of 85bar) and separate control routes away from the pipelines...
February 28, 2018: Science of the Total Environment
Vincent Tan, Anthony De Girolamo, Tahereh Hosseini, Jameel Aljariri Alhesan, Lian Zhang
This paper attempts to develop a modified chemical percolation devolatilization (M-CPD) model that can include heat transfer, primary pyrolysis and the secondary cracking reactions of volatiles together to describe the pyrolysis of waste scrap tyre chip, as well as to examine the influence of operating conditions on the scrap tyre pyrolysis product yields. Such a study has yet to be conducted in the past, thereby leading to a large knowledge gap failing to understand the pyrolysis of the coarse feedstock appropriately...
March 16, 2018: Waste Management
Liping Zhao, Qingxiang Meng, Yan Li, Hao Wu, Yunlong Huo, Xinzhuang Zhang, Zhenming Zhou
BACKGROUND: This study was conducted to examine effects of nitrate on ruminal methane production, methanogen abundance, and composition. Six rumen-fistulated Limousin×Jinnan steers were fed diets supplemented with either 0% (0NR), 1% (1NR), or 2% (2NR) nitrate (dry matter basis) regimens in succession. Rumen fluid was taken after two-week adaptation for evaluation of in vitro methane production, methanogen abundance, and composition measurements. RESULTS: Results showed that nitrate significantly decreased in vitro ruminal methane production at 6 h, 12 h, and 24 h (P < 0...
March 20, 2018: BMC Microbiology
Jae-Min Choi, Sun-Kee Han, Chae-Young Lee
This study was performed to optimize thermal hydrolysis pretreatment (THP) of sewage sludge for enhanced anaerobic digestion (AD). Using the response surface methodology (RSM), the optimal conditions were found 180 °C of reaction temperature and 76 min of reaction time. Through THP under optimal conditions, high molecular substances in sewage sludge such as soluble microbial by-products (SMPs) and extracellular polymeric substances (EPSs) were hydrolyzed into low molecular ones without the generation of refractory compounds...
February 27, 2018: Bioresource Technology
Jianbin Guo, Xian Cui, Hui Sun, Qian Zhao, Xiaoyu Wen, Changle Pang, Renjie Dong
In north China, large amounts of excessively wilted maize stover are produced annually. Maize stover wet storage strategies and subsequent biogas production was examined in this study. Firstly, wet storage performances of harvested maize stover, air-dried for different time durations, were evaluated. Results showed that optimal storage performance was obtained when the initial water soluble carbohydrate (WSC) content after air-drying was higher than 8.0%. Therefore, cellulase and glucose were added to the excessively wilted maize stover to achieve the targeted pre-storage WSC levels...
March 10, 2018: Bioresource Technology
Jun Gu, Qin Yang, Yu Liu
The conventional biological processes for municipal wastewater are facing the challenges of high energy consumption and production of excessive sludge. To address these two emerging issues, this study demonstrated the feasibility to integrate mainstream anammox into an A-2B process for municipal wastewater treatment towards energy-efficient operation with reduced sludge production. In the proposed A-2B process, an anaerobic fixed bed reactor (AFBR) served as A-stage for COD capture, an anammox moving bed biofilm reactor (MBBR) was employed as B2-stage, which received effluent containing nitrite from a sequencing batch reactor (SBR) at B1-stage...
February 21, 2018: Water Research
G A McAuliffe, T Takahashi, R J Orr, P Harris, M R F Lee
With increasing concern about environmental burdens originating from livestock production, the importance of farming system evaluation has never been greater. In order to form a basis for trade-off analysis of pasture-based cattle production systems, liveweight data from 90 Charolais × Hereford-Friesian calves were collected at a high temporal resolution at the North Wyke Farm Platform (NWFP) in Devon, UK. These data were then applied to the Intergovernmental Panel on Climate Change (IPCC) modelling framework to estimate on-farm methane emissions under three different pasture management strategies, completing a foreground dataset required to calculate emissions intensity of individual beef cattle...
April 2018: Data in Brief
Marietta Zita Poles, Nikolett Bódi, Mária Bagyánszki, Éva Fekete, András Tamás Mészáros, Gabriella Varga, Szilárd Szűcs, Anna Nászai, Liliána Kiss, Andrey V Kozlov, Mihály Boros, József Kaszaki
Our aim was to characterize the main components of the nitrosative response with quantitative changes of the nitrergic myenteric neurons in adjacent intestinal segments after transient superior mesenteric artery occlusion. We also tested the hypothesis that exogenous methane may modulate the evolution of nitroxidation by influencing xanthine oxidoreductase (XOR) activity. The microcirculatory consequences of a 50min ischemia or ischemia-reperfusion were investigated in anesthetized rats (n=124) inhaling normoxic air with or without 2...
March 14, 2018: Free Radical Biology & Medicine
S van Gastelen, E C Antunes-Fernandes, K A Hettinga, J Dijkstra
Several in vivo CH4 measurement techniques have been developed but are not suitable for precise and accurate large-scale measurements; hence, proxies for CH4 emissions in dairy cattle have been proposed, including the milk fatty acid (MFA) profile. The aim of the present study was to determine whether recently developed MFA-based prediction equations for CH4 emission are applicable to dairy cows with different diacylglycerol o-acyltransferase 1 (DGAT1) K232A polymorphism and fed diets with and without linseed oil...
March 14, 2018: Journal of Dairy Science
S van Gastelen, H Mollenhorst, E C Antunes-Fernandes, K A Hettinga, G G van Burgsteden, J Dijkstra, J L W Rademaker
The objective of the present study was to compare the prediction potential of milk Fourier-transform infrared spectroscopy (FTIR) for CH4 emissions of dairy cows with that of gas chromatography (GC)-based milk fatty acids (MFA). Data from 9 experiments with lactating Holstein-Friesian cows, with a total of 30 dietary treatments and 218 observations, were used. Methane emissions were measured for 3 consecutive days in climate respiration chambers and expressed as production (g/d), yield (g/kg of dry matter intake; DMI), and intensity (g/kg of fat- and protein-corrected milk; FPCM)...
March 14, 2018: Journal of Dairy Science
Tamsin Lyons, Anita Bielak, Evelyn Doyle, Björn Kuhla
Considerable interest exists both from an environmental and economic perspective in reducing methane emissions from agriculture. In ruminants, CH4 is produced by a complex community of microorganisms that is established in early life but can be influenced by external factors such as feed. Although CH4 emissions were thought to be constant once an animal reached maturity, recent studies have shown that CH4 yield significantly increases from early to late lactation in dairy cows. The aim of this study was to test the hypothesis that increases in CH4 yield over the lactation cycle are related to changes in rumen microbial community structure...
March 14, 2018: Journal of Dairy Science
Qing Feng, Young-Chae Song, Yongtae Ahn
The role of anaerobic microorganisms suspended in the bulk solution on methane production was investigated in a bioelectrochemical anaerobic reactor with the electrode polarized at 0.5 V. The electron transfer from substrate to methane and hydrogen were 25% and 7.5%, respectively, in the absence of the anaerobic microorganisms in the bulk solution. As the anaerobic microorganisms increased to 4400 mg/L, the electrons transferred to methane increased to 83.3% but decreased to 0.3% in hydrogen. The electroactive microorganisms (EAM), including exoelectrogens and electrotrophs, enriched in the bulk solution that confirmed by the redox peaks in the cyclic voltammogram was proportional to the anaerobic microorganism...
March 8, 2018: Bioresource Technology
P Buffière, M Dooms, S Hattou, H Benbelkacem
The role of the hydrolytic stage in high solids temperature phased anaerobic digestion was investigated with a mixture of cattle slurry and maize silage with variable ratios (100, 70 and 30% volatile solids coming from cattle slurry). It was incubated for 48 h at 37, 55, 65 and 72 °C. Soluble chemical oxygen demand and biochemical methane potential were measured at 0, 24 and 48 h. Higher temperatures improved the amount of solubilized COD, which confirmed previously reported results. Nevertheless, solubilization mostly took place during the first 24 h...
March 8, 2018: Bioresource Technology
Suverna Trivedi, Ram Prasad
Compressed natural gas (CNG) is most appropriate an alternative of conventional fuel for automobiles. However, emissions of carbon-monoxide and methane from such vehicles adversely affect human health and environment. Consequently, to abate emissions from CNG vehicles, development of highly efficient and inexpensive catalysts is necessary. Thus, the present work attempts to scan the effects of precipitants (Na2 CO3 , KOH and urea) for nickel cobaltite (NiCo2 O4 ) catalysts prepared by co-precipitation from nitrate solutions and calcined in a lean CO-air mixture at 400°C...
March 2018: Journal of Environmental Sciences (China)
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