scholarly journals Characterization of microscopic disorder in reconstructed porous materials and assessment of mass transport-relevant structural descriptors

2016 ◽  
Vol 40 (5) ◽  
pp. 3993-4015 ◽  
Author(s):  
Tibor Müllner ◽  
Klaus K. Unger ◽  
Ulrich Tallarek
Keyword(s):  
Mass Transport ◽  
Porous Materials ◽  
Structural Descriptors

Solvent-free dynamic nuclear polarization enhancements in organically modified mesoporous silica

2021 ◽  
Author(s):  
Marcos de Oliveira Jr. ◽  
Kevin Herr ◽  
Martin Brodrecht ◽  
Nadia Berenice Haro-Mares ◽  
Till Wissel ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Porous Materials ◽  
Structural Characterization ◽  
Dynamic Nuclear Polarization ◽  
High Field ◽  
Nuclear Polarization ◽  
Organically Modified ◽  
Field Dynamic ◽  
Free Dynamic

High-field Dynamic Nuclear Polarization is a powerful tool for the structural characterization of species on the surface of porous materials or nanoparticles. For these studies the main source of polarization...

scholarly journals Synthesis and Characterization of Mixed Metal Oxide Nanocomposite Energetic Materials

2003 ◽  
Vol 800 ◽  
Author(s):  
Brady J. Clapsaddle ◽  
Lihua Zhao ◽  
Alex E. Gash ◽  
Joe H. Satcher ◽  
Kenneth J. Shea ◽  
...  
Keyword(s):  
Mass Transport ◽  
Metal Oxide ◽  
Energetic Materials ◽  
Silicon Oxide ◽  
Sol Gel ◽  
Synthesis And Characterization ◽  
Mixed Metal Oxide ◽  
Organic Additives ◽  
Metal Oxide Silicon

ABSTRACTIn the field of composite energetic materials, properties such as ingredient distribution, particle size, and morphology, affect both sensitivity and performance. Since the reaction kinetics of composite energetic materials are typically controlled by the mass transport rates between reactants, one would anticipate new and potentially exceptional performance from energetic nanocomposites. We have developed a new method of making nanostructured energetic materials, specifically explosives, propellants, and pyrotechnics, using sol-gel chemistry. A novel sol-gel approach has proven successful in preparing metal oxide/silicon oxide nanocomposites in which the metal oxide is the major component. Two of the metal oxides are tungsten trioxide and iron(III) oxide, both of which are of interest in the field of energetic materials. Furthermore, due to the large availability of organically functionalized silanes, the silicon oxide phase can be used as a unique way of introducing organic additives into the bulk metal oxide materials. As a result, the desired organic functionality is well dispersed throughout the composite material on the nanoscale. By introducing a fuel metal into the metal oxide/silicon oxide matrix, energetic materials based on thermite reactions can be fabricated. The resulting nanoscale distribution of all the ingredients displays energetic properties not seen in its microscale counterparts due to the expected increase of mass transport rates between the reactants. The synthesis and characterization of these metal oxide/silicon oxide nanocomposites and their performance as energetic materials will be discussed.

scholarly journals The Impact of Microstructure Geometry on the Mass Transport in Artificial Pores: A Numerical Approach

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Matthias Galinsky ◽  
Ulf Sénéchal ◽  
Cornelia Breitkopf
Keyword(s):  
Mass Transport ◽  
Porous Materials ◽  
Effective Diffusion ◽  
Direct Simulation Monte Carlo ◽  
Numerical Approach ◽  
Porous System ◽  
Length Scales ◽  
General Evaluation ◽  
Pulse Experiment ◽  
The Impact

The microstructure of porous materials used in heterogeneous catalysis determines the mass transport inside networks, which may vary over many length scales. The theoretical prediction of mass transport phenomena in porous materials, however, is incomplete and is still not completely understood. Therefore, experimental data for every specific porous system is needed. One possible experimental technique for characterizing the mass transport in such pore networks is pulse experiments. The general evaluation of experimental outcomes of these techniques follows the solution of Fick’s second law where an integral and effective diffusion coefficient is recognized. However, a detailed local understanding of diffusion and sorption processes remains a challenge. As there is lack of proved models covering different length scales, existing classical concepts need to be evaluated with respect to their ability to reflect local geometries on the nanometer level. In this study, DSMC (Direct Simulation Monte Carlo) models were used to investigate the impact of pore microstructures on the diffusion behaviour of gases. It can be understood as a virtual pulse experiment within a single pore or a combination of different pore geometries.

Characterization of porous materials by small-angle scattering

Pramana ◽  
2004 ◽  
Vol 63 (1) ◽  
pp. 165-173 ◽  
Author(s):  
S. Mazumder ◽  
D. Sen ◽  
A. K. Patra
Keyword(s):  
Porous Materials ◽  
Small Angle ◽  
Small Angle Scattering ◽  
Angle Scattering

Characterization of step-edge barrier crossing of para-sexiphenyl on the ZnO (101̄0) surface

2016 ◽  
Vol 18 (36) ◽  
pp. 25329-25341 ◽  
Author(s):  
Karol Palczynski ◽  
Philipp Herrmann ◽  
Georg Heimel ◽  
Joachim Dzubiella
Keyword(s):  
Thin Film ◽  
Mass Transport ◽  
Organic Molecules ◽  
Optoelectronic Devices ◽  
Thin Film Deposition ◽  
Essential Elements ◽  
Transport Processes ◽  
Film Deposition ◽  
Conjugated Organic Molecules

Mass transport processes of conjugated organic molecules (COMs) on inorganic surfaces are essential elements in thin film deposition for hybrid optoelectronic devices.

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