Austrian Center for Electronic Microscopy and Nanoanalysis

Graz, Austria

Austrian Center for Electronic Microscopy and Nanoanalysis

Graz, Austria
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Fladischer K.,University of Graz | Fladischer K.,Austrian Center for Electronic Microscopy and Nanoanalysis | Reingruber H.,University of Graz | Reingruber H.,University of New South Wales | And 26 more authors.
New Journal of Physics | Year: 2010

Manipulation of atomic and molecular beams is essential to atom optics applications including atom lasers, atom lithography, atom interferometry and neutral atom microscopy. The manipulation of charge-neutral beams of limited polarizability, spin or excitation states remains problematic, but may be overcome by the development of novel diffractive or reflective optical elements. In this paper, we present the first experimental demonstration of atom focusing using an ellipsoidal mirror. The ellipsoidal mirror enables stigmatic off-axis focusing for the first time and we demonstrate focusing of a beam of neutral, ground-state helium atoms down to an approximately circular spot, (26.8 ± 0.5)μm × (31.4 ± 0.8)μm in size. The spot area is two orders of magnitude smaller than previous reflective focusing of atomic beams and is a critical milestone towards the construction of a high-intensity scanning helium microscope. © IOP Publishing Ltd and Deutsche Physikalische Gesellschan.

Littringer E.M.,Research Center Pharmaceutical Engineering GmbH | Mescher A.,Institute of Mechanical Engineering | Schroettner H.,Austrian Center for Electronic Microscopy and Nanoanalysis | Achelis L.,University of Bremen | And 2 more authors.
European Journal of Pharmaceutics and Biopharmaceutics | Year: 2012

The aim of this work was to study the performance of mannitol carrier particles of tailored surface roughness in dry powder inhaler formulations. Carrier particles of different surface roughness were prepared by spray drying of aqueous mannitol solutions at different outlet temperatures at a pilot-scale spray dryer. However, the carrier particles did not only change in surface roughness but also in shape. This is why the impact of carrier shape on the performance of carrier based dry powder inhalates was evaluated also. The highest fine particle fraction (FPF), that is the amount of active pharmaceutical substance, delivered to the deep lung, is achieved when using rough, spherical carrier particles (FPF = 29.23 ± 4.73%, mean arithmetic average surface roughness (mean Ra) = 140.33 ± 27.75 nm, aspect ratio = 0.925). A decrease of surface roughness (mean Ra = 88.73 ± 22.25 nm) leads to lower FPFs (FPF = 14.62 ± 1.18%, aspect ratio = 0.918). The FPF further decreases when irregular shaped particles are used. For those particles, the micronized active accumulates within the cavities of the carrier surface during the preparation of the powder mixtures. Upon inhalation, the cavities may protect the active from being detached from the carrier. © 2012 Elsevier B.V. All rights reserved.

Nikolic I.,University of Montenegro | Crossed D Signurovic D.,Institute of Public Health of Montenegro | Blecic D.,University of Montenegro | Zejak R.,University of Montenegro | And 3 more authors.
Minerals Engineering | Year: 2013

The results of synthesis of fly ash based geopolymers and the experimental investigations of the geopolymerization of fly ash in the presence of eclectic arc furnace dust were presented. The electric arc furnace dust (EAFD) is a hazardous solid waste formed during remelting processes of iron and steel scrap in an electric arc furnace. In this work, the possibility of immobilization of Zn (as a most abundant toxic metal in EAFD) from EAFD and the influence of EAFD addition and alkaline dosage on the mechanical and microstructural properties of fly ash based geopolymers was investigated. Our result show that the best mechanical properties of FA and FE geopolymers were obtained using 10 M NaOH and 10 wt.% EAFD. The X-ray phase analysis confirmed the presence of aluminosilicate and oxide phases in investigated samples of FA, EAFD, as well as FA and FE geopolymers. SEM-EDS results have revealed the presence of Zn in an amorphous aluminosilicate phase. This material is considered as mesoporous and the change of porosity is greatly dependent on the alkaline dosage. The efficiency of immobilization of Zn from EAFD was evaluated using TCLP, EN 12457-2 and EPA Method 1313 leaching tests. Results of TCLP and EN 12457-2 tests have shown that the increase of alkaline dosage leads to the more effective immobilization of Zn and other toxic metals present in EAFD. On the other hand, the results of EPA method 1313-pH dependent leaching test have indicated that FE geopolymers are relatively stable in neutral and alkali environment while in a pH range 2-5.5, solubility of Zn and Pb is a concern for this type of materials. © 2013 Elsevier Ltd. All rights reserved.

Pucher H.,University of Graz | Schwaiger N.,University of Graz | Schwaiger N.,BDI BioEnergy International AG | Feiner R.,University of Graz | And 5 more authors.
Green Chemistry | Year: 2015

New biomass utilization technologies and concepts are needed to suffice future increasing energy demand. This paper contributes to the understanding of liquid phase pyrolysis (LPP) oil upgrading, which significantly differs from fast pyrolysis (FP) oil upgrading processes. A two-step hydrodeoxygenation (HDO) process was established to convert the LPP oil into a biofuel with diesel fuel-like properties. In the first HDO step (250 °C, 85 bar), the bulk of the water and most of the highly-oxygenated water-soluble carbonaceous constituents were removed, to lower hydrogen consumption in the second HDO step. In addition, the highly reactive compounds were stabilized in the first step. In the second HDO step (400°C, 150/170 bar), the product specification was improved. This paper shows a proof-of-principle for a two-step HDO process for converting LPP oil to a diesel-like biofuel. This journal is © The Royal Society of Chemistry 2015.

Zia Q.,Martin Luther University of Halle Wittenberg | Ingolic E.,Austrian Center for Electronic Microscopy and Nanoanalysis | Androsch R.,Martin Luther University of Halle Wittenberg
Colloid and Polymer Science | Year: 2010

The morphology/habit of crystals of cold-crystallized poly(ethylene terephthalate) (PET) has been evaluated using scanning and transmission electron microscopy and using atomic force microscopy. The combination of different preparation and analysis techniques allowed assessing the structure at the nanometer scale of films of PET at both the surface and the bulk. It is found that crystals formed on heating the amorphous glass to a temperature higher than the glass transition temperature are of lamellar shape in the bulk and almost isometric habit at the surface. This finding is explained by different rates of nucleation/crystallization in the bulk and at the surface, being supported by the observation of nanometer-scale surface heterogeneities after quenching PET to ambient temperature before crystallization was initiated by heating. © 2010 Springer-Verlag.

Prohaska M.,University of Leoben | Mori G.,University of Leoben | Grill R.,Voestalpine AG | Tischler G.,Voestalpine AG | Mitsche S.,Austrian Center for Electronic Microscopy and Nanoanalysis
Materials and Corrosion | Year: 2013

The influence of parameters of a thermo-mechanical rolling process on corrosion properties of materials 316L and Alloy 825 was studied by means of the DL-EPR-method and a conventional corrosion test. Prior to polarization measurements, optimization of the DL-EPR-method was conducted. SEM was used to characterize microstructure and type of attack before and after corrosion testing. A strong correlation between annual corrosion rates and DL-EPR-test results was obtained. Due to the low tendency of both alloys to form corrosion-promoting precipitates, the applicable range of process parameters for both alloys is large and the fabrication process in general is not critical. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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