Field emission hydrocarbon

Heats of adsorption were scarce, limiting any thermodynamic analysis of catalytic reactions, while the significance of surface structure had not been addressed. Where heats of adsorption were available there was a conflict between data obtained by those advocating the clean surface (Beeck) and technical catalyst (Eucken) approaches. Taylor drew attention to Muller s (then recent) field emission microscope and the potential of deuterium in isotopic exchange studies an aspect that Kemball, who had worked in Princeton used to much advantage in unravelling the mechanism of hydrocarbon... 

The Biocube aerobic biofilter is an ex situ off-gas filtration system that is commercially available. The technology utilizes microbes to biologically oxidize volatile organic compounds (VOCs) and complex odors. It can be used in conjunction with vapor-vacuum-extraction (VVE), a process that draws gases from subsurface soil. These gases often require further treatment before being released into the atmosphere. Biocube has been field tested and has been implemented at over 100 sites for the treatment of hydrocarbon vapors. The technology has also been successfully used for odor control at a variety of sites. In addition, the Biocube system can treat odor and VOC emissions simultaneously. The units are modular, so additional stacks can be added as needed for increased flow and/or removal rates. 

The emphasis on environmental protection in the last three decades, as industrial and economic growth gave birth to many forms of pollution threatening human health and Earth ecosystems, resulted in the growth of environmental catalysis. So, catalysts ate not only used to promote processes in the production field, but also to reduce the emissions of undesirable or hazardous compounds to the environment. For example, catalytic combustion has been proposed and developed as an effective method for controlling the emissions of hydrocarbons and carbon monoxide. 

As mentioned earlier, the oxidation of carbon monoxide and hydrocarbons should be achieved simultaneously with the reduction of nitrogen oxides. However, the first reaction needs oxygen in excess, whereas the second one needs a mixture (fuel-oxygen) rich in fuel. The solution was found with the development of an oxygen sensor placed at exhaust emissions, which would set the air-to-fuel ratio at the desired value in real time. So, the combination of electronics and catalysis and the progress in these fields led to better control of the exhaust emissions from automotive vehicles. 

A different type of economic study, initiated in 1969, used an empirical formulation to develop economic estimates of vegetation damage (6). On the thesis that hydrocarbon emissions are related to oxidant production, hydrocarbon emission data were collected from over 100 metropolitan areas in the United States. Reductions in crop yields were empirically related to these emissions, and the monetary values were calculated. The reliability of this technique was based on known effects of oxidants on crop species and on the known relationship between hydrocarbons and oxidants. There are disadvantages to the method used, and the results suffer from lack of field verification. However, the technique has obvious advantages such as ease of use and uniformity of results. It might be a prototype from which more accurate estimates can be developed. Results from two years of development are found in annual reports (6, 7) and show between 100-125 million dollars lost annually in the United States. 

Very small grains and macromolecules are known to be present in the surface layers of some disks as well as in the ISM. They are usually revealed by emission features due to polycyclic aromatic hydrocarbons (PAHs, see also Chapter 6). These particles, with frameworks of six to several thousand carbon atoms, are so small that they can be excited by single ultraviolet photons. Subsequently, they will non-thermally re-radiate the energy in discrete, but broad, bands stretching across the mid-infrared wavelength region. They are found in protoplanetary disks when the ultraviolet radiation field is sufficiently high (Habart et al. 2004), but... 

We have made both field and laboratory measurments of the emission of CH4 and CO2 from both higher and lower termite families (Macro-termes, mound building species, Cubitermes, soil feeders, Trinervitermes, Reticulitermes, lower termites, and Gnathermitermes). Similarly, we have made laboratory measurements of the emission of CH4, CO2, CO, H2, C2 to Cio hydrocarbons, and reduced sulphur species from Reticulitermes and Gnathermitermes species. In addition, emissions from arboreal nests of an unidentified species of Nasutitermitinae were sampled in the field in Guatemala and analyzed for CH4 and C2 to Cio hydrocarbons [9]. 

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