Vienna University of Technology

About: Vienna University of Technology is a education organization based out in Vienna, Austria. It is known for research contribution in the topics: Laser & Context (language use). The organization has 16723 authors who have published 49341 publications receiving 1302168 citations.

Environmental impacts of phosphorus recovery from municipal wastewater

Abstract: Phosphorus mining from phosphate rock is associated with economic as well as environmental concerns. Through phosphorus recovery from municipal wastewater, countries could decrease their dependency on the global phosphate rock market, however, conceivably leading to an increase in environmental impacts from fertilizer production. In this work 18 phosphorus recovery technologies are evaluated in terms of cumulative energy demand, global warming potential and acidification potential with the methodology of life cycle analysis. These indicators are then contrasted with other environmental criteria, i.e. recovery potential, heavy metal and organic micropollutant decontamination potential and fertilizer efficiency, to determine their overall environmental performance. The LCA shows that a broad spectrum of changes in gaseous emissions and energy demand can be expected through the implementation of P recovery from wastewater. Linkage to further environmental performance results exposes certain trade-offs for the different technologies. Recovery from the liquid phase has mostly positive or comparably little impacts on emissions and energy demand but the low recovery potential contradicts the demand for efficient recycling rates. For recovery from sewage sludge, those technologies that already are or are close to being applied full-scale, are associated with comparatively high emissions and energy demand. Recovery from sewage sludge ash shows varying results, partly revealing trade-offs between heavy metal decontamination, emissions and energy demand. Nevertheless, recovery from ash is correlated with the highest potential for an efficient recycling of phosphorus. Further research should include implications of local infrastructures and legal frameworks to determine economically and environmentally optimised P recovery and recycling concepts.

WC grain growth and grain growth inhibition in nickel and iron binder hardmetals

Abstract: WC grain growth and growth inhibition of an 0.6 μm FSSS WC powder (average SEM size: 0.35 μm) were studied in WC–10 wt% Ni alloys by adding 0–2 wt% of inhibitor carbides (VC, Cr 3 C 2 , TaC, TiC and ZrC). Alloy gross carbon content turned out to be a crucial factor for WC growth in Ni alloys, even with high inhibitor additions. Coarsening was more pronounced in high carbon alloys, compared with low carbon grades, resulting in a significantly lower hardness. VC proved to be by far the most effective grain growth inhibitor in WC–Ni hardmetals, followed by TaC, Cr 3 C 2 , TiC and ZrC. Hardness increased with increasing amount of additive but reached a maximum above which it remained about the same. Experiments on WC–Fe–(VC) alloys revealed that WC grain growth is strongly restricted in Fe-binder alloys, even without additions of growth inhibitors. Binder chemistry thus strongly influences both continuous and discontinuous WC grain growth. This chemistry is determined by the nature of the binder matrix (Fe, Co, Ni), the alloy gross carbon content (which determines the composition of the binder matrix) as well as the inhibitor additive.

Aerogels from unaltered bacterial cellulose: application of scCO2 drying for the preparation of shaped, ultra-lightweight cellulosic aerogels.

Abstract: Bacterial cellulose produced by the gram-negative bacterium Gluconacetobacter xylinum was found to be an excellent native starting material for preparing shaped ultra-lightweight cellulose aerogels. The procedure comprises thorough washing and sterilization of the aquogel, quantitative solvent exchange and subsequent drying with supercritical carbon dioxide at 40 degrees C and 100 bar. The average density of the obtained dry cellulose aerogels is only about 8 mg x cm(-3) which is comparable to the most lightweight silica aerogels and distinctly lower than all values for cellulosic aerogels obtained from plant cellulose so far. SEM, ESEM and nitrogen adsorption experiments at 77 K reveal an open-porous network structure that consists of a comparatively high percentage of large mesopores and smaller macropores.

Trichoderma-plant-pathogen interactions: advances in genetics of biological control.

Abstract: Trichoderma spp. are widely used in agriculture as biofungicides. Induction of plant defense and mycoparasitism (killing of one fungus by another) are considered to be the most important mechanisms of Trichoderma-mediated biological control. Understanding these mechanisms at the molecular level would help in developing strains with superior biocontrol properties. In this article, we review our current understanding of the genetics of interactions of Trichoderma with plants and plant pathogens.