Emission characteristics, with respect

With respect to fuels utilized as heating fuels for industrial furnaces, or as motor fuels for large diesel engines such as those in ships or power generation sets, the characteristics of primary importance are viscosity, sulfur content and the content of extremely heavy materials (asphaltenes) whose combustion can cause high emissions of particulates which are incompatible with antipollution legislation. 

Due to its particular composition, biodiesel is biodegradable and allows reduced emissions, in terms of particulates and polycyclic aromatic hydrocarbons. Instead, the results of the combustion of biodiesel are contentious in relation to so-called NOx emissions, where it has been observed that such emissions are more or less increased, with respect to conventional diesel, depending on the characteristics of the engine in which it is used ... 

We may thus conclude after this short overview on DeNO technologies that NH3-SCR using catalysts based on V-W-oxides supported on titania is a well-established technique for stationary sources of power plants and incinerators, while for other relevant sources of NO, such as nitric acid tail gases, where emissions are characterized from a lower temperature and the presence of large amounts of NOz, alternative catalysts based on transition metal containing microporous materials are possible. Also, for the combined DeNO -deSO, alternative catalysts would be necessary, because they should operate in the presence of large amounts of SO,.. Similarly, there is a need to develop new/improved catalysts for the elimination of NO in FCC emissions, again due to the different characteristics of the feed with respect to emissions from power plants. 

Here, L total is the depth of the etched hole per pulse and is assumed to be the sum of photochemical and photothermal contributions, Tphoto and Thermal, respectively 0Ceff is the effective photon absorption coefficient of the medium and can vary with laser emission characteristics, e g., photon density Fis the incident laser fluence Fth is the medium s threshold fluence A and F are the effective frequency factor with units of pm/pulse and the effective activation energy with units of J/cm2, respectively, for the zeroth-order thermal rate constant F0, comparable in magnitude to Fth, is important only at low fluences.64 Equation (5) is obtained after assuming that the polymer temperature T in the laser-exposed region of mass mp and the thermal rate constant k are given, respectively, as... 

A different approach which also starts from the characteristics of the emissions is able to deal with some of these difficulties. Aerosol properties can be described by means of distribution functions with respect to particle size and chemical composition. The distribution functions change with time and space as a result of various atmospheric processes, and the dynamics of the aerosol can be described mathematically by certain equations which take into account particle growth, coagulation and sedimentation (1, Chap. 10). These equations can be solved if the wind field, particle deposition velocity and rates of gas-to-particle conversion are known, to predict the properties of the aerosol downwind from emission sources. This approach is known as dispersion modeling. 

Again, there is a resemblance between the emission of DPCs and those of the diphenylmethyl radicals. The emission maximum of DPCs is blue-shifted by 20-50 nm with respect to that of the radicals. For example, diphenylmethyl radical exhibits its emission at 535 nm. Another characteristic difference between these two species is that the lifetime of DPC is significantly shorter than that of the first excited state of the diphenylmethyl radical. 

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