نتایج جستجو برای: ch4
تعداد نتایج: 7336 فیلتر نتایج به سال:
در این مطالعه اثر افزودن ذرات Materials Institute Lavoisier-53, MIL 53 بر خواص گاز تراوایی غشای پلی متیل پنتین (PMP) ارزیابی شد.MIL-53با ترکیب درصدهای 10، 20 و %30 وزنی به ماتریس پلیمری اضافه شد. خواص MIL-53 و غشاهای ساخته شده به روش های مختلفی نظیر آزمون FTIR،SEM و TGA بررسی شد. همچنین آزمون جذب گازهای CO2 و CH4 برای بررسی هر چه دقیق تر خواص گاز تراوایی غشاهای حاصل انجام و داده های جذب با ...
equilibrium adsorption property of multi-walled carbon nanotubes with oh group was studied using experimental design for the adsorption of co2 , ch4 and h2 . the effect of temperature, pressure, their binary interactions and quadratic terms were studied for adsorption capacity of nanotubes and the results were analyzed by the face centered central composite design method and analysis of varianc...
Pervasive anoxia in the subsurface ocean during the Proterozoic may have allowed large fluxes of biogenic CH4 to the atmosphere, enhancing the climatic significance of CH4 early in Earth's history. Indeed, the assumption of elevated pCH4 during the Proterozoic underlies most models for both anomalous climatic stasis during the mid-Proterozoic and extreme climate perturbation during the Neoprote...
[1] Anaerobic oxidation of methane (AOM) is a considerable sink for the greenhouse gas methane (CH4) in marine systems, but the importance of this process in terrestrial systems is less clear. Lowland boreal soils and wet tropical soils are two hot spots for CH4 cycling, yet AOM has been essentially uncharacterized in these systems. We investigated AOM in soils from sites in Alaska and Puerto R...
Methane (CH4) is produced as an end product from feed fermentation in the rumen. Yield of CH4 varies between individuals despite identical feeding conditions. To get a better understanding of factors behind the individual variation, 73 dairy cows given the same feed but differing in CH4 emissions were investigated with focus on fiber digestion, fermentation end products and bacterial and archae...
Sources and sinks of methane (CH4) are critical for understanding global biogeochemical cycles and their role in climate change. A growing number of studies have reported that CH4 concentrations in cave ecosystems are depleted, leading to the notion that these subterranean environments may act as sinks for atmospheric CH4. Recently, it was hypothesized that this CH4 depletion may be caused by r...
The prediction of methane outputs from ruminant livestock data at farm, national, and global scales is a vital part of greenhouse gas calculations. The objectives of this work were to quantify the effect of physiological stage (lactating or nonlactating) on predicting methane (CH4) outputs and to illustrate the potential improvement for a beef farming system of using more specific mathematical ...
Sequestration of carbon dioxide (CO2) in the form of its hydrates in natural methane (CH4) hydrate reservoirs, via CO2/CH4 exchange, is an attractive pathway that also yields valuable CH4 gas as product. In this paper, we describe a macroscale experiment to form CO2 and CH4-CO2 hydrates, under seafloor-mimic conditions, in a vessel fitted with glass windows that provides visualization of hydrat...
Tropospheric CH4 concentration depends, according to modeled tropospheric processes, on many factors, including emissions of CH4 as well as NOx and CO. Illustrative analyses of the relation between emissions and CH4 concentration give some guidance on the role of CH4 in the stabilization of greenhouse gas concentrations. The contribution of CH4 to radiative forcing at the time of stabilization ...
Atmospheric methane (CH4) increased from ∼900 ppb (parts per billion, or nanomoles per mole of dry air) in 1900 to ∼1800 ppb in 2010 at a rate unprecedented in any observational records. However, the contributions of the various methane sources and sinks to the CH4 increase are poorly understood. Here we use initial emissions from bottom-up inventories for anthropogenic sources, emissions from ...
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