Plasma, cold

Grill A 1994 Cold Plasma in Materials Fabrication from Fundamentals to Applications (New York IEEE)... 

The degree of ionization increases with temperature, and at 6000-8000 K, where ionization efficiencies are 90 to 95%, nearly all atoms exist as ions in the plasma. Operation of the plasma torch under conditions that produce a cooler flame (cold plasma) has important advantages for some applications, which are discussed after the next section. 

Although cold plasmas have benefits in removing interfering ions such as ArO+, they are not necessary for other applications where interferences are not a problem. Thus, in laboratories where a range of isotopes needs to be examined, the plasma has to be changed between hot and cold conditions, whereas it is much simpler if the plasma can be run under a single set of conditions. For this reason, some workers use warm plasmas, which operate between the hot and cold conditions. 

The cold plasmas tend to be unstable, are sometimes difficult to maintain, and provide ion yields that are less than those of the hot plasmas. To obviate the difficulties of the interfering isobaric molecular ions from hot plasmas, it has been found highly beneficial to include a collision cell (hexapole see Chapter 22) before the mass analyzer itself. This collision cell contains a low pressure of hydrogen gas. lon/molecule collisions between the hydrogen and, for example, ArO+... 

R. Manory and A. GriU, Protective Coatings of Metal Sufaces by Cold Plasma Treatments, NASA Technical Memorandum 87152, National Technical Information Service, Springfield, Va., 1985. 

Plasma Types. Eigure 1 (7—9) indicates the various types of plasmas according to their electron density and electron temperature. The colder or low electron energy regions contain cold plasmas such as interstellar and interplanetary space the earth s ionosphere, of which the aurora boreaUs would be a visible type alkaU-vapor plasmas some flames and condensed-state plasmas, including semiconductors (qv). 

A. GtiU, Cold Plasma in Materials Technology From Fundamentals to Applications, IEEE, Piscataway, N.J., 1994. 

Ishikawa, M., Sakamoto, A., Morita, M., Matsuda, Y. and Ishida, K., Effect of treatment of activated carbon fiber cloth electrodes with cold plasma upon performance of electric double layer capacitors, J. Power Sources, 1996, 60(2), 233 238. 

Brosse et al. [41] modified isotactic polypropylene and other polyolefins by a cold plasma. In isotactic polypropylene, plasma treatment results in a polypropylene crystallization of paracrystalline or smectic form into a a-crystalline form. Further, the active films are susceptible to react with monomers in a postgrafting reaction. 

Electric discharge (corona, cold plasma) is another method of physical treatment. Corona treatment is one of the most interesting techniques for surface oxidation activation. This process changes the surface energy of the cellulose fibers [28]. In the case of wood surface activation it increases the amount of aldehyde groups [291. 

The same effects are reached by cold plasma treatment. Depending on the type and the nature of the used gases, a variety of surface modification can be achieved. 

Some physical techniques can be classified into flame treatments, corona treatments, cold plasma treatments, ultraviolet (UV) treatment, laser treatments, x-ray treatments, electron-beam treatments, ion-beam treatments, and metallization and sputtering, in which corona, plasma, and laser treatments are the most commonly used methods to modify silicone polymers. In the presence of oxygen, high-energy-photon treatment induces the formation of radical sites at surfaces these sites then react with atmospheric oxygen forming oxygenated functions. 

A. Grill, Cold Plasmas for Materials Fabrication." IEEE Press, New York, 1994. 

Combustion Calorimetric bomb (Berthelot), oxygen flask (Schoniger), Wickbold apparatus, cold plasma incinerator, micro-Dumas combustion (CHN analyser), sulfur-specific analysers (S, C, N, O), pyrochemiluminescence... 

In the Wickbold method, solid samples are vaporised in an oxygen stream and fed into an oxyhydrogen flame, which bums in a cooled quartz tube. The combustion products are condensed here, or are captured in an absorption solution as gaseous materials. Although combustion in a Wickbold apparatus is a quick and effective method for destroying organic material of all types, incomplete destruction may occur [19]. In special digestion vessels, known as cold-plasma ashers (CPA),... 

TXRF has also been used for the characterisation of single, colourless textile fibres (polyesters, modified cellulose and wool), yielding a fingerprint trace-element pattern, suitable for forensic purposes [276,277], Sample preparation involved dissolution/predigestion in HN03 and matrix removal (O2 cold plasma). 

Cold plasma with reduced temperature is another way to cope with the most annoying problems from interferences, even in the case of low-resolution instruments [394], The effect consists of weaker ionisation conditions coming close to chemical ionisation [395]. In particular, argides are reduced by orders of magnitude in comparison to conventional ICP operation. However, at lower plasma temperatures, evaporation of analyte material is considerably reduced. Reducing the plasma temperature also has a dramatic effect on the ionisation (and therefore sensitivity) of many elements. Table 8.65 shows the ion population as a function of plasma temperature and ionisation potential. As a result, the cold plasma technique is only advantageous for a rather small number of elements and applications. 

Partial oxidation is also mentioned as a process to convert ethanol to hydrogen.124 Another novel technology for ethanol to hydrogen has been described by Toci and Modica.125 It is based on cracking ethanol vapors by "cold-plasma-chemical processing" in the presence of a Ni-based catalyst. 

USING OF COLD PLASMA FOR PURIFICATION OF CHEMICALLY POLLUTED WATER IN EXTREME PERIOD... 

Cold Plasma for Purification of Chemically Polluted Water... 

Kehm K, Hauri EH, Alexander CMOD, Carlson RW (2003) High precision iron isotope measurements of meteoritic material by cold plasma ICP-MS. Geochim Cosmochim Acta 67 2879-2891... 

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