Aerosole und ihre technische Bedeutung

Heidenreich, Steffen; Büttner, H.; Ebert, Fritz

doi:10.1002/cite.200306141

Cited by 13 publications

(3 citation statements)

References 115 publications

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“…The small size of the grains points to a strong supersaturation of the carbon vapor in the condensation zone resulting in a high number of nucleation seeds. This is based on the assumption that, generally, homogeneous nucleation needs a high supersaturation of the vapor phase (Granquist & Buhrman 1976;Heidenreich et al 2003). The relation between the size of the critical grains r * and the Gibbs free energy is defined by the equation r * = −2γ/∆G v , where γ stands for the surface energy of the condensed species (Cao 2004).…”

Section: Resultsmentioning

confidence: 99%

Formation of Polycyclic Aromatic Hydrocarbons and Carbonaceous Solids in Gas-Phase Condensation Experiments

Jäger

Huisken

Mutschke

et al. 2009

ApJ

171

156

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Carbonaceous grains represent a major component of cosmic dust. In order to understand their formation pathways, they have been prepared in the laboratory by gas-phase condensation reactions such as laser pyrolysis and laser ablation. Our studies demonstrate that the temperature in the condensation zone determines the formation pathway of carbonaceous particles. At temperatures lower than 1700 K, the condensation by-products are mainly polycyclic aromatic hydrocarbons (PAHs), that are also the precursors or building blocks for the condensing soot grains. The low-temperature condensates contain PAH mixtures that are mainly composed of volatile 3-5 ring systems. At condensation temperatures higher than 3500 K, fullerene-like carbon grains and fullerene compounds are formed. Fullerene fragments or complete fullerenes equip the nucleating particles. Fullerenes can be identified as soluble components. Consequently, condensation products in cool and hot astrophysical environments such as cool and hot AGB stars or Wolf Rayet stars should be different and should have distinct spectral properties.

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Section: Resultsmentioning

confidence: 99%

Formation of Polycyclic Aromatic Hydrocarbons and Carbonaceous Solids in Gas-Phase Condensation Experiments

Jäger

Huisken

Mutschke

et al. 2009

ApJ

171

156

View full text Add to dashboard Cite

show abstract

“…Stable droplets of sizes between 50 and 500 nm are produced by suppressing the coalescence and ripening by the surfactants and osmotic pressure agent. In the early twentyfirst century, the next-generation research works focused on the vapor-phase reactions, where the properties of the desired nanoparticles are achieved in the early phases of the reaction by the fluid and particle dynamic interactions (Heidenreich et al 2003). The smaller particles are formed by achieving supersaturation through higher cooling rate of hot reaction gases used in the synthesis.…”

Section: Synthesis Of Nanoparticlesmentioning

confidence: 99%

Advanced approach for degradation of recalcitrant by nanophotocatalysis using nanocomposites and their future perspectives

Padmanaban¹,

Nandagopal

Priyadharshini³

et al. 2016

Int. J. Environ. Sci. Technol.

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Industrial effluents containing persistent pollutants play a significant role in environmental pollution. Classical techniques such as chlorination, coagulation, ion flotation, membrane process and sedimentation that have been used to decontaminate polluted water are incapable of efficient degradation due to the generation of secondary pollutants. Photocatalysis, an advanced oxidation process in which the photoreaction is accelerated by the irradiation of catalyst, has shown efficient degradation of recalcitrant in water system. Usage of nanoparticles as homogenous photocatalyst has become prevalent due to their improved properties such as large surface-to-volume ratio, controlled uniform particle size and its composition which enhances the degradation rate. The recombination of holes and electron pair which is considered to be the limitation in homogenous system can be overcome by nanocomposites or heterogeneous photocatalysts. This system decreases the rate of recombination, leading to effective degradation of individual pollutants because of their enhanced physicochemical and structural properties. In recent years, heterogeneous nanophotocatalytic processes employing titanium dioxide (TiO 2 ) and zinc oxide (ZnO) composites have gained immense research interest as an effective wastewater treatment method because of its efficacy in decomposing and mineralizing the hazardous organic and inorganic pollutants utilizing the UV and visible photons.This paper reviews about the process, synthesis and parameters influencing photocatalytic reaction and their kinetics with much emphasize on types of nanoparticles and nanocomposites and its application in wastewater treatment.

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“…Different generation methods and techniques exist to produce test aerosols. The generation techniques influence the properties of the generated particles . An aerosol generator should produce airborne particles with constant size, shape, and concentration over time.…”

Section: Introductionmentioning

confidence: 99%

Aerosol Generation of Nonspherical Particles by Desublimation of Copper Phthalocyanine

et al. 2019

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A novel generator for a defined test aerosol consisting of nonspherical particles was developed based on the desublimation of copper phthalocyanine during adiabatic cooling. Employing a brush disperser, copper phthalocyanine powder is dosed and dispersed in a nitrogen flow and sublimated in a tube furnace. Downstream the furnace new particles are formed due to the adiabatic expansion and the desublimation of the material in a laval nozzle. The generated particles were characterized employing a scanning mobility particle sizer and an aerosol particle mass analyzer to determine the size distribution and the dynamic shape factor. For the operating parameters of the generator examined here, particles with a mobility diameter between 30 and 600 nm were generated. The measured values for the dynamic shape factor of the particles were confirmed by scanning electron microscopy analysis.

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Aerosole und ihre technische Bedeutung

Cited by 13 publications

References 115 publications

Formation of Polycyclic Aromatic Hydrocarbons and Carbonaceous Solids in Gas-Phase Condensation Experiments

Formation of Polycyclic Aromatic Hydrocarbons and Carbonaceous Solids in Gas-Phase Condensation Experiments

Advanced approach for degradation of recalcitrant by nanophotocatalysis using nanocomposites and their future perspectives

Aerosol Generation of Nonspherical Particles by Desublimation of Copper Phthalocyanine

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