scholarly journals Water in exoplanets

2012 ◽  
Vol 370 (1968) ◽  
pp. 2749-2764 ◽  
Author(s):  
Giovanna Tinetti ◽  
Jonathan Tennyson ◽  
Caitlin A. Griffith ◽  
Ingo Waldmann
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Radiative Transfer ◽  
Research Effort ◽  
Pressure Broadening ◽  
Detailed Consideration ◽  
Significant Research ◽  
Final Confirmation ◽  
Methane Carbon

Exoplanets—planets orbiting around stars other than our own Sun—appear to be common. Significant research effort is now focused on the observation and characterization of exoplanet atmospheres. Species such as water vapour, methane, carbon monoxide and carbon dioxide have been observed in a handful of hot, giant, gaseous planets, but cooler, smaller planets such as Gliese 1214b are now analysable with current telescopes. Water is the key chemical dictating habitability. The current observations of water in exoplanets from both space and the ground are reviewed. Controversies surrounding the interpretation of these observations are discussed. Detailed consideration of available radiative transfer models and linelists are used to analyse these differences in interpretation. Models suggest that there is a clear need for data on the pressure broadening of water transitions by H 2 at high temperatures. The reported detections of water appear to be robust, although final confirmation will have to await the better quality observational data provided by currently planned dedicated space missions.

RUMEN GAS ANALYSIS BY GAS-SOLID CHROMATOGRAPHY

1961 ◽  
Vol 41 (2) ◽  
pp. 187-196 ◽  
Author(s):  
J. M. McArthur ◽  
J. E. Miltimore
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Hydrogen Sulphide ◽  
Sample Volume ◽  
Gas Analysis ◽  
Complete Analysis ◽  
Thermal Detector ◽  
Thermal Detection ◽  
Methane Carbon

Methods are described for sampling and analysing rumen gases. The analysis requires less than 15 minutes for the determination of hydrogen, oxygen, nitrogen, methane, carbon monoxide, carbon dioxide, and hydrogen sulphide, i.e., for all gases occurring in the rumen. The method is sensitive and requires only a small quantity of sample, and the sample volume need not be known. The presence of water or other vapours in the sample does not influence the results. Relative thermal detector responses have been determined for gases which occur in the rumen. These eliminate the necessity for the calibration of gas chromatographs using thermal detection. The first complete analysis of rumen gas is presented.

Characterization of Methane Number for Producer Gas Blends

2013 ◽  
Author(s):  
Daniel M. Wise ◽  
Daniel B. Olsen ◽  
Myoungjin Kim
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Natural Gas ◽  
Producer Gas ◽  
Combustion Pressure ◽  
Natural Gas Engines ◽  
Gaseous Fuels ◽  
Combustion Properties ◽  
Methane Number

Producer gas, any of a variety of gases generated from biomass gasification, is a renewable gaseous fuel that can be burned in gas engines for power production. Producer gas consists primarily of methane, hydrogen, carbon monoxide, carbon dioxide, and nitrogen. These gas blends can be problematic as a fuel for natural gas engines due to widely varying composition and significantly different fuel properties than natural gas. Characterization of combustion properties of different producer gas compositions is critical if the gas engine is to be operated reliably and at the greatest efficiency possible. A sample space of 35 producer gas blends consisting of distinct percentages of combustible gases (methane, hydrogen, and carbon monoxide) and diluent (carbon dioxide and nitrogen) is created to provide a basis for methane number testing. A test cell is established to mix producer gas blends of desired constituent makeup for consumption in a Waukesha F2 Cooperative Fuel Research (CFR) engine to directly measure methane number for each blend. Additional measurements include combustion pressure statistics, fuel consumption, and power output. Methane number is correlated to combustion pressure statistics and producer gas properties. Methane number measurements are compared with predictions using the software AVL Methane, often employed by engine manufacturers to characterize gaseous fuels. Measured methane number shows a strong correlation to 0–10% and 10–90% burn durations. The predicted methane number values from AVL Methane are significantly different than measured methane number in many cases. The error in the prediction is strongly dependent on the amount of carbon monoxide and hydrogen in the producer gas.

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