نتایج جستجو برای: ch4 gas sensor
تعداد نتایج: 431364 فیلتر نتایج به سال:
The low O2 content of the Archean atmosphere implies that methane should have been present at levels approximately 10(2) to 10(3) parts per million volume (ppmv) (compared with 1.7 ppmv today) given a plausible biogenic source. CH4 is favored as the greenhouse gas that countered the lower luminosity of the early Sun. But abundant CH4 implies that hydrogen escapes to space (upward arrow space) o...
Dry reforming is a process allowing simultaneous conversion of hydrocarbons (methane being the prototype molecule used for this study) to syngas using carbon dioxide as an oxidizing agent. Such strategy may eventually become an opportunity for the industrial sector to produce syngas whilst valorizing residual CO2. As reported previously, an iron-based catalyst, i.e. steel wool, activated by an ...
The production and consumption of the greenhouse gases (GHGs) methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O) in soil profile are poorly understood. This work sought to quantify the GHG production and consumption at seven depths (0-30, 30-60, 60-90, 90-150, 150-200, 200-250 and 250-300 cm) in a long-term field experiment with a winter wheat-summer maize rotation system, and four N a...
This study was conducted to evaluate the performance of an innovative two-stage process, BIOCELL, that was developed to produce hydrogen (H2) and methane (CH4) from food waste on the basis of phase separation, reactor rotation mode, and sequential batch technique. The BIOCELL process consisted of four leaching-bed reactors for H2 recovery and post-treatment and a UASB reactor for CH4 recovery. ...
There is increasing interest in the measurement of methane (CH4) emissions from tree stems in a wide range of ecosystems so as to determine how they contribute to the total ecosystem flux. To date, tree CH4 fluxes are commonly measured using rigid closed chambers (static or dynamic), which often pose challenges as these are bulky and limit measurement of CH4 fluxes to only a very narrow range o...
Pervaporation and gas separation performances of polymer membranes can be improved by crosslinking or addition of metal-organic frameworks (MOFs). Crosslinked copolyimide membranes show higher plasticization resistance and no significant loss in selectivity compared to non-crosslinked membranes when exposed to mixtures of CO2/CH4 or toluene/cyclohexane. Covalently crosslinked membranes reveal b...
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...
In this study we developed LaNixAl1-xO3 perovskite systems using a sol-gelmethod (with propionic acid as solvent) to use in methane-reforming reactions for producing synthesis gas. To understand the roles of the nature of the precursor and calcination conditions on the formation of LaNixAl1-xO3, we carried out identifications using NMR, FT-IR, XRD, SEM, and TEM. The precursor struc...
The ratio of CH4/CO in comets is an important indicator of the region of their formation. However, it is diicult to measure the quantity of CH4. The Giotto Ion Mass Spectrometer experiment observed a quantity of CH + which seemed inconsistent with the amount of CH4 observed. Thus, it was proposed that a source of the CH + was a distributed source in the dust. We tested this hypothesis by observ...
[1] Airborne measurements of methane (CH4) and carbon dioxide (CO2) were taken over the rice growing region of California’s Sacramento Valley in the late spring of 2010 and 2011. From these and ancillary measurements, we show that CH4 mixing ratios were higher in the planetary boundary layer above the Sacramento Valley during the rice growing season than they were before it, which we attribute ...
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