Aerosol characteristics, metal

The exploding wire method involves putting a large amount of energy into a wire suddenly, causing it to explode. If 02 is present, a metal oxide aerosol is produced, whereas particles of pure metal are formed in an inert atmosphere such as helium. Exploding wire generators and their size distribution characteristics have been discussed by Phalen (1972). 

It is hard to imagine a world without aluminum-based materials. From the foil that we wrap leftovers with, to the cans that house beverages and deodorant aerosols, our world is inundated with applications for aluminum. The widespread use of this metal is a direct result of its availability - 8.3 wt% in the earth s crust, making it the most naturally abundant metal. The malleability of A1 is second only to gold, and it possesses other desirable characteristics such as nonsparking, high thermal/electrical conductivity, corrosion resistance, and high ductility. 

Four different routes were employed for the synthesis of iron-oxide-based redox water-sphtting materials Solid-State Synthesis (SSS), Self-Propagating High-Temperature Synthesis (SHS), Gel Combustion (GC) and Aerosol Spray Pyrolysis (ASP) [8]. These synthesis methods were chosen with the rationale to exploit particular characteristics of each one for the synthesis of products with tunable oxygen vacancies concentration. The synthesis details have been reported previously [8], therefore only the general reaction concepts are reported below, where A and B denote the bivalent dopant metals Ni, Mn or Zn. 

A cross-flow nebulizer for dc arc solution and AAS work was described by Valente and Schrenk [113]. For ICP work the nebulizer should have capillaries with diameters < 0.2 mm and a distance of 0.05-0.5 mm between the tips. The capillaries also can be made of metal, glass or plastic and they have similar characteristics to the concentric nebulizer. Types made of Ryton for example enable the aspiration of solutions containing higher concentrations of HF. Then aerosol gas flows are around 1-2 L/min at 2-5 bar. This has been confirmed by optimization measurements described by Fujishiro et al. [114]. They found that by varying the inside and the outside diameters of the capillary from 0.15 to 0.9 mm and from 0.5 to 1.5 mm, respectively, the pressure drop across the sample tube decreases from 150 to 50 mbar. By increasing the gas flow from 0.75 to 1.75 L/min, the pressure drop across the sample tube was found to increase from 150 to 350 mbar. As shown in Fig. 43 [114], the variations in the drops in pressure considerably influence the droplet size. 

One characteristic source of metals in waste materials is that of the metallurgical industry (with potential target media). These include aerosols/particulates con-... 

In principle, tellurium deposition on stainless steel in the primary system would largely prevent this element from being released to the containment. However, tellurium vapor could react chemically with a variety of metallic aerosols to form tellurides in particular it has a high affinity for silver and cadmium, as well as for tin volatilized from the Zircaloy claddings. Thus, tellurium transport through the primary system would be primarily controlled by aerosol transport characteristics. Spence and Wright (1987) have calculated that inclusion of these processes of depo-... 

Recent advances in aerosol and combustion science and engineering now allow scalable flame synthesis of mixed oxides, metal salts, and even pure metals in the form of nanoparticles and films with closely controlled characteristics [71-76]. Flame processes are classified into vapor-fed and liquid-fed, depending on the employed state of the metal precursor [77]. Liquid-fed flame processes are distinguished for their flexibility in producing materials of various compositions and morphologies that result in unique product functionalities. 

Mermet et al. [72] have systematically studied LA-ICP-AES of metallic additives in polymers, i.c. PE/(Ca, Sn, Ti) and PVC/(Ca, Sn, Ti). In this fundamental study particular attention was paid to crater and aerosol particle characteristics, LOD, matrix effects by polymer type and chemical nature of the additives, fractionation and composition of vapour fraction. The characteristics of the crater generated and the aerosol depend on the polymer nature. The ablation mechanisms for PVC and PE are quite different. LOD is related to both the polymer and additive chemical form, thus requiring an internal standard (IS). Carbon is not a good IS for some inorganic elements [72,83,85,86]. 

A flame emission photometer consists of an atomizer by which the sample is transformed into an aerosol spray before it is introduced into the flame. In the flame the metal atoms emit light of a wavelength characteristic to that element. The light passes through filters or diffraction gratings which isolate a single spectral line, and its intensity is measured by a photoelectric device. Internal standards can be used to compensate for variations in the intensity of the flame, e.g. lithium if sodium and potassium are being measured. 

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