نتایج جستجو برای: ch4

تعداد نتایج: 7336  

2014
Li Chen Hirokazu Ueta Helen Chadwick Rainer D. Beck

We report a molecular beam study of the effect of vibrational excitation on the physisorption of methane on a Pt(111) surface. Our experiments use a continuous molecular beam of CH4, prepared in its antisymmetic C−H stretch mode ν3 by infrared laser pumping via rapid adiabatic passage. Physisorbed CH4(ads) is detected on a Pt(111) surface by reflection absorption infrared spectroscopy. At a sur...

2017
Per Milberg Lina Törnqvist Lars M. Westerberg David Bastviken

Methane (CH4) emissions via emergent aquatic macrophytes can contribute substantially to the global CH4 balance. We addressed temporal variability in CH4 flux by using the static chamber approach to quantify fluxes from plots dominated by two species considered to differ in flux transport mechanisms (Phragmites australis, Carex rostrata). Temporal variability in daily mean emissions from early ...

Journal: :Chemosphere 2005
Hermann W Bange Günther Uher

We conducted irradiation experiments with riverine, estuarine, and marine water samples to investigate the possibility of photochemical methane (CH4) formation. CH4 photoproduction was undetectable under oxic conditions or in the absence of methyl radical precursors indicating that its photochemical formation is negligible in the present ocean. Significant photochemical CH4 production was obser...

2014
Tony Pham Katherine A. Forrest Brant Tudor Sameh K. Elsaidi Mona H. Mohamed Keith McLaughlin Christian R. Cioce Michael J. Zaworotko Brian Space

Grand canonical Monte Carlo (GCMC) simulations of CO2 and CH4 sorption and separation were performed in dia-7i-1-Co, a metal-organic material (MOM) consisting of a 7-fold interpenetrated net of Co(2+) ions coordinated to 4-(2-(4-pyridyl)ethenyl)benzoate linkers. This MOM shows high affinity toward CH4 at low loading due to the presence of narrow, close fitting, one-dimensional hydrophobic chann...

Journal: :Physical chemistry chemical physics : PCCP 2005
Howard S Lacheen Enrique Iglesia

The dynamics of carburization of Mo-oxo precursors exchanged onto H-ZSM-5 strongly influence initial induction periods and steady-state rates during catalytic pyrolysis of CH4 to alkenes and arenes at 900-1000 K. The effects of co-reactants and of activating conditions were examined by on-line time-resolved mass spectrometric analysis of effluent streams using rigorous analyses to account for e...

2017
Minmin Sun Yuan Zhang Jing Ma Wenping Yuan Xianglan Li Xiao Cheng

The Sanjiang Plain (SJP), one of the major rice producing regions in China, is an important source of methane (CH4) emissions. However, there have been large uncertainties in the estimates of CH4 emissions from this area during the past few years. In this study, we estimated CH4 emissions using a process-based model derived by rice area, CH4 flux, land surface temperature (LST), and the ratio o...

Journal: :Journal of animal physiology and animal nutrition 2017
J L Vanegas J González M D Carro

Incubations were carried out with batch cultures of ruminal micro-organisms from sheep to analyse the influence of the N source on in vitro CH4 production. The two substrates were mixtures of maize starch and cellulose in proportions of 75:25 and 25:75 (STAR and CEL substrates, respectively), and the three nitrogen (N) sources were ammonia (NH4 Cl), casein (CA) and isolated soya bean protein (S...

Journal: :Chemical communications 2015
Akshita R Dutta Poorvajan Sekar Muslim Dvoyashkin Clifford R Bowers Kirk J Ziegler Sergey Vasenkov

High field NMR diffusometry reveals single-file diffusion of CO/CH4 mixture in dipeptide nanochannels with a coincident mobility for CO and CH4. In contrast to the relationship commonly observed for normal diffusion, this mixture mobility is only slightly smaller than that of pure CO which diffuses much faster than pure CH4.

2013
D. M. Olson T. J. Griffis A. Noormets R. Kolka J. Chen

[1] Three years (2009–2011) of near-continuous methane (CH4) and carbon dioxide (CO2) fluxes were measured with the eddy covariance (EC) technique at a temperate peatland located within the Marcell Experimental Forest, in northern Minnesota, USA. The peatland was a net source of CH4 and a net sink of CO2 in each year with annual carbon budgets of 26.8 ( 18.7), 15.5 ( 14.8), and 14.6 ( 21.5) g C...

2015
M. D. FRASER H. R. FLEMING V. J. THEOBALD J. M. MOORBY

To investigate the extent to which enteric methane (CH4) emissions from growing lambs are explained by simple body weight and diet characteristics, a 2 × 2 Latin square changeover design experiment was carried out using two sheep breeds and two fresh pasture types. Weaned lambs of two contrasting breed types were used: Welsh Mountain (WM, a small, hardy hill breed) and Welsh Mule × Texel (TexX,...

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