Carbonaceous particles

Two types of carbon electrodes are in widespread use. Prebaked carbon electrodes (Fig. 5) are those made from a mixture of carbonaceous particles and a coal-tar pitch binder. The electrode is formed by extmsion or mol ding from a heated plasticlike mix and subsequently baked. Final bake temperature is sufficient to carbonize the binder, ie, about 850°C. At this temperature the binder is set, all volatiles have left, and a significant portion of the product shrinkage has occurred. 

Engines. Vehicular petrol engines are potential ignition sources by means of the spark-ignition system, dynamo or battery, or hot exhaust pipe. Non-flameproof diesel engines are potential ignition sources due to a hot exhaust pipe or carbonaceous particles or flames from the exhaust. 

Soot deposited on the chamber wall contained mostly carbonaceous particles, where no MWNTs were contained. The deposits on the cathode consist of two portions the inside is black fragile core and the outside hard shell. The inside include MWNTs scad poljd ral graphitic nanoparticles. The outer-shell part ojnsisted of the crystd of graphite. 

Fig. 4 shows the SEM images of SWNTs purified by the thermal oxidation and acid-treated. Fig. 4(a) shows a SEM image of the raw soot. In addition to the bundle of SWNTs, carbonaceous particles are shown in the figure. These stractural features mi t be causal by various in the arcing process because of an inhomogeneous distribution of catalysts in the anodes [7]. It can be seen that the appearance of SWNTs was curled and quite different fiom that of MWNTs. Fig. 4(b) shows a decrease of amorphous carbons after oxidation. The basic idea of the selective etching is that amorphous carbons can be etched away more easily than SWNTs due to the faster oxidation reaction rate [2]. Since the CNTs are etched away at the same time, the yield is usually low. The transition metals can be etched away by an add treatment. Fig. 4(c) shows the SEM image of the acid-treated sample, where the annealed sample was immersed in 10 % HCl. 

The elastic modulus of laminated composite plate in which an ER silicone gel of carbonaceous particles is sandwiched between two PVC sheets also changed under the influence of an electric field. It was found that an electric field of 1.17 kV/mm caused a gain in the elastic modulus of the gel of 13% [57]. 

Particles found in a diffuse cloud show a simpler chemistry consisting of silicate core, some carbonaceous particles and a thin ice mantel containing a small... 

Isotopic and chemical patterns are given for an ambient sample (downtown Portland) and four sources of carbonaceous particles. The source C contributions (Ct) are expressed as percent of total aerosol mass, and the subscripts refer to Vegetation (slash burning), Road dust, Oil (residual and distillate), and Auto exhaust. Units for the ordinate are also percent of total aerosol mass, except for, 4C which is expressed as dpm/g-aerosol. Abscissa points for each pattern are ordered as l4C, C, Si, Ni, and Pb. 

Kaden, D. A., Thilly, W. G., Mutagenic Activity of Fossil Fuel Combustion Products, Conference on Carbonaceous Particles in the Atmosphere, T. Novakov, ed., University of California, Berkeley, 193, 1978. 

Fast pyrolysis oil is an acidic viscous dark brown liquid (Fig. 6.6) containing oxygenated hydrocarbons, water and small carbonaceous particles including some minerals. 

Carbon black consists of spherical particles (diameter less than 50 nm) that may aggregate and form agglomerates (-250 nm diameter) [1], The carbonaceous particles... 

Bitterle E, Karg E, Schroeppel A, Kreyling WG, Tippe A, Ferron GA, Schmid O, Heyder J, Maier KL, Hofer T (2006) Dose-controlled exposure of A549 epithelial cells at the air-liquid interface to airborne ultrafine carbonaceous particles. Chemosphere 65 1784—1790... 

Similarly, the emission of soot from many practical devices, as well as from flames, is determined by the rate of oxidation of these carbonaceous particles as they pass through a flame zone and into the post-combustion gases. As mentioned in the previous chapter, the soot that penetrates the reaction zone of a co-annular diffusion flame normally bums if the temperatures remain above 1300K. This soot combustion process takes place by surface oxidation. 

Currie LA, Klouda GA, Continetti RE, Kaplan IR, Wong WW, Dzubay TG, Stevens RK, On the origin of carbonaceous particles in American cities Results of radiocarbon dating and chemical characterization. Radiocarbon 25 603-614, 1983. 

Simoneit BRT, Biogenic Hpids in eolian particulates collected over the ocean, in NovakovT ed), Proceedings Carbonaceous Particles in the Atmosphere NSF-LBL, pp. 233-244, 1979. 

Fisher, G. L. Crisp, C. E. Hays, T. L. Carbonaceous Particles in Coal Fly Ash. In Proceedings of the Conference on Carbonaceous Particles in the Atmosphere, Lawrence Berkeley Laboratory Report LBL-9037, CONF-7803131, UC-11, 1978. 

When sources are studied, several things should be done to provide data needed for receptor-model applications. First, particles should be collected In at least two different size fractions corresponding to the division at about 2.5-ym dlam now used In many studies of ambient aerosols. In some cases. It may be desirable to have more size cuts. As noted above, compositions of particles from coal combustion change dramatically below about 0.5-pm dlam (44, 46). Above we Identified a minimum of about twenty elements that should be measured. Also, In order to develop adequate markers for sources that emit carbonaceous particles, measurements of organic compounds and other properties related to carbonaceous particles should be made. 

Johnson, R.L. Huntzlcker, J.J. "Analysis of volatilizable and elemental carbon in ambient aerosols", in "Proceedings Carbonaceous Particles in the Atmosphere", T. Novakov, Ed., Lawrence Berkeley Laboratory, Berkeley, California, June 1979, 10-13. 

Malissa, H. in T. Novakov, Ed., "Proceedings, Carbonaceous Particles in the Atmosphere " Lawrence Berkeley Laboratory Berkeley, California, 1978 pp. 3-9. 

Carbonaceous particles suspended in aqueous solutions can also act as sites for efficient S02 oxidation. For example, Novakov and co-workers have studied the kinetics of such processes with respect to the concentrations of 02, S(IV), and carbon particles as well as the pH and temperature dependencies (Brodzinsky et al., 1980 Chang et al., 1981 Benner et al., 1982). 

Baldwin, A. C., Heterogeneous Reactions of Sulfur Dioxide with Carbonaceous Particles, Int. J. Chem. Kinet., 14, 269-277 (1982). 

Penner, J. E., and T. Novakov, Carbonaceous Particles in the Atmosphere A Historical Perspective to the Fifth International Conference on Carbonaceous Particles in the Atmosphere, J. Geophys. Res., 101, 19373-19378(1996). 

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