نتایج جستجو برای: ch4 purification

تعداد نتایج: 63718  

2017
Neus Garcias-Bonet Carlos M. Duarte

Atmospheric methane (CH4) is the second strongest greenhouse gas and it is emitted to the atmosphere naturally by different sources. It is crucial to define the dimension of these natural emissions in order to forecast changes in atmospheric CH4 mixing ratio in future scenarios. However, CH4 emissions by seagrass ecosystems in shallow marine coastal systems have been neglected although their gl...

2011
Anna Neubeck Nguyen Thanh Duc David Bastviken Patrick Crill Nils G Holm

Hydrocarbons such as CH4 are known to be formed through the Fischer-Tropsch or Sabatier type reactions in hydrothermal systems usually at temperatures above 100°C. Weathering of olivine is sometimes suggested to account for abiotic formation of CH4 through its redox lowering and water splitting properties. Knowledge about the CH4 and H2 formation processes at low temperatures is important for t...

2006
Ulrich Wand Alfred Wegener Vladimir A. Samarkin Georgia Horst-Michael Nitzsche Hans-Wolfgang Hubberten

We found unprecedentedly high abundances of microbially produced CH4 in the anoxic deep waters of Lake Untersee, an oligotrophic, perennially ice-covered Antarctic freshwater lake. The maximum CH4 concentration (approaching 21.8 6 1.4 mmol L21) is one of the highest observed so far in a natural aquatic ecosystem. Although surficial lake sediments are the predominant source of CH4 in Lake Unters...

2014
P. Ricci M. G. G. Chagunda J. Rooke J. G. M. Houdijk A. Waterhouse

The laser methane detector (LMD) has been proposed as a method to characterize enteric methane (CH4) emissions from animals in a natural environment. To validate LMD use, its CH4 outputs (LMD-CH4), were compared against CH4 measured with respiration chambers (chamber-CH4). The LMD was used to measure CH4 concentration (μL/L) in the exhaled air of 24 lactating ewes and 72 finishing steers. In ew...

2017
Xuexin Shao Xuancai Sheng Ming Wu Hao Wu Xiao Ning

Changes in the hydrological conditions of coastal wetlands may potentially affect the role of wetlands in the methane (CH4) cycle. In this study, the CH4 production potential and emissions from restored coastal reed wetlands at different water levels were examined in eastern China at a field scale in two phenological seasons. Results showed that the total CH4 flux from reeds at various water le...

2008
David Bastviken Jonathan J. Cole Michael L. Pace Matthew C. Van de Bogert

[1] Methane (CH4) represents a major product of organic matter decomposition in lakes. Once produced in the sediments, CH4 can be either oxidized or emitted as a greenhouse gas to the atmosphere. Lakes represent an important source of atmospheric CH4, but the relative magnitudes of the internal pathways that lead to CH4 emissions are not yet clear. We quantified internal cycling and methane emi...

2004
Yaping Xiao Daniel J. Jacob James S. Wang Jennifer A. Logan Paul I. Palmer Parvadha Suntharalingam Robert M. Yantosca Glen W. Sachse Donald R. Blake

Aircraft observations of Asian outflow from the TRACE-P aircraft mission over the NW Pacific (March-April 2001) show large CH4 enhancements relative to background, as well as strong CH4-C2H6-CO correlations that provide signatures of regional sources. We apply a global chemical transport model simulation of the CH4-C2H6-CO system for the TRACE-P period to interpret these observations in terms o...

2014
Tahereh Asadi Mohammad Reza Ehsani T. Asadi

Copper trimesate (Cu-BTC) MOF has been pointed out as a promising adsorbent for separating carbon dioxide from methane. However, MOF’s need to be shaped prior to their use in packed bed adsorbers in order to reduce pressure drop; on the other hand, the production of mechanically resistant shaped bodies reduces their adsorption performance. In this work, Cu-BTC tablets provided by BASF are evalu...

2017
Mei Wang Jianghua Wu Junwei Luan Peter Lafleur Huai Chen Xinbiao Zhu

Although estimates of the annual methane (CH4) flux from agriculturally managed peatlands exist, knowledge of controls over the variation of CH4 at different time-scales is limited due to the lack of high temporal-resolution data. Here we present CH4 fluxes measured from May 2014 to April 2016 using the eddy covariance technique at an abandoned peatland pasture in western Newfoundland, Canada. ...

2016
S. S. Peng S. L. Piao P. Bousquet P. Ciais B. G. Li X. Lin S. Tao Z. P. Wang Y. Zhang F. Zhou

Methane (CH4) has a 28-fold greater global warming potential than CO2 over one hundred years. Atmospheric CH4 concentration has tripled since 1750. Anthropogenic CH4 emissions from China have been growing rapidly in the past decades, and contribute more than 10% of global anthropogenic CH4 emissions with large uncertainties in existing global inventories, generally limited to country-scale stat...

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