Derivation of the Landau quantum hydrodynamics for interacting bose systems

In this work we demonstrate that the basic equations of the Landau hydrodynamics may be derived directly from the quantum-mechanical microscopic N-body Hamiltonian, which is expressed as a functional of the local observables, namely, particle and current densities. The Landau quantum hydrodynamic equations are then the Heisenberg equations of motion of these quantities.     

Zur Wirkung von Magnesiumoxyd und Tonerde in flüssigen Hochofenschlacken

Die Basizität flüssiger Hochofenschlacken. Die Verknüpfung der Gehalte der Eisenschmelzen und der Schlacken trotz des dauernden Fortschreitens der Reaktionen des Kohlenstoffs bei 1550 °C. Zusatz von Magnesiumoxyd zu CaO-Al₂O₃-SiO₂-Schlacken mit 0 bzw. 5 bzw. 10 bzw. 20 bzw. 30% Al₂O₃ bis zu den Mengenverhältnissen (MgO)/(CaO) = 0,36 bzw. 0,72. Die Kieselsäuregehalte der Schlacken als zweckmäßige Veränderliche zur bildlichen Darstellung der Kennzahlen der Querreaktionen.     

Zum Einfluß der Temperatur auf die Reaktionen zwischen Eisenschmelzen,Hochofenschlacken und elementarem Kohlenstoff

Die Wirkung des Kohlenstoffs als Reduktionsmittel auf die Schlacke CaO (40%)–MgO (10%)–SiO₂ (40%)–Al₂O₃ (10%) und Eisenschmelzen mit anfangs 1,5 bzw. 2,7% S bei 1450, 1550 und 1650 °C im Verlauf von 6 h. Vorgabe der Wirkung des Kohlenstoffs durch Siliziumzusatz zur Eisenschmelze und entsprechenden Kieselsäureabzug von der Schlacke bei nur 0,5 h Reaktionsdauer.     

Entmischungsverhalten eines perlitarmen,mit Niob mikrolegierten Baustahles bei isothermer Auslagerung

Untersuchung des Entmischungsverhaltens eines perlitarmen, nioblegierten Baustahles mit 0,10% C und 0,05% Nb bei isothermer Auslagerung bei 600 °C. Ermittlung von Art, Verteilung, Form und Größe der Niobausscheidungen sowie der mechanischen Eigenschaften in Abhängigkeit von der Auslagerungsdauer. Vergleich mit einem niobfreien Baustahl ähnlicher chemischer Zusammensetzung.     

Der Einfluß der Alkalioxyde auf die Reaktionen zwischen kohlenstoffreichen Eisenschmelzen und Ca-Mg-Al-Silikaten

Schlacken mit 2% Na₂O. Einfluß des Mengenverhältnisses von Eisenschmelze und Schlacke auf die Endgehalte nach 30 min Reaktionsdauer bei 1350, 1450, 1550 und 1650 °C. Einfluß des Basengrades der Schlacke auf die Endgehalte. Schlacken mit 3% K₂O. Verdampfen der Alkalien. Analysenwerte zum Verhalten des Stickstoffs gegenüber den alkalihaltigen Schlacken.     

Eisenschmelzen und Hochofenschlacken im Graphittiegel bei längerer Schmelzdauer

Die starke Veränderlichkeit des Siliziumgehaltes von Eisenschmelzen unter Silikat-Sulfidschlacken im Graphittiegel. Vier verschiedene CaO-MgO(10%)-Al₂O₃(10%)-SiO₂-Schlacken reagieren 5 min bis 6 h lang bei 1550 °C mit siliziumarmen, aber schwefelreichen Eisenschmelzen. Der Umsatz des Kohlenstoffs bei verschieden oxydierenden Bedingungen zu Anfang. Die Verknüpfung der Konzentrationen von Silizium, Mangan, Eisen und Schwefel als Folge der Querreaktionen. Die umgesetzten Mengen, das weite Überwiegen der Kieselsäurereduktion durch Kohlenstoff. Berechnung des Ablaufes der Einzelreaktionen und des Gesamtumsatzes aus demjenigen einer Reaktion mit Hilfe der Kennzahlen der Querreaktionen.     

Occurrence and origin of phosphine in landfill gas

A landfill (Hooge Maey, Flanders, Belgium) was subjected to an in-depth study in order to explain the origin of phosphine detected in high amounts in landfill gas, in comparison with biogas from other sources, during a previous study. The spatial and temporal variability of the phosphine concentration in landfill gas was assessed. Twenty-four wells were monitored and differences in phosphine concentration up to one log unit were observed (3.2-32.4 microg/m(3)). The phosphine concentration in each well was constant in time over a period of 4 months. No correlation was found between the phosphine concentration and methane, carbon dioxide, hydrogen sulfide, ethene or ethane concentration. In a series of laboratory tests, it was shown that phosphine was emitted during batch fermentation tests inoculated with landfill leachate when Fe(0) or Al(0) specimens were added. Conditions favouring corrosion of iron gave rise to higher emissions of phosphine. The phosphine concentration in the headspace of a batch test rose to 1.43 mg/m(3) after 27 days of incubation. Weight loss of corroding steel coupons correlated with phosphine emission. Calculations showed that all phosphine emitted from the 0.005 km(3) landfill (160 g/year) could be attributed to corrosion of metals. No evidence of de novo synthesis could be established.     

Multi-input and multi-output neural model of the mechanical nonlinear behaviour of a PEM fuel cell system

A fuel cell system model is necessary to prepare and analyse vibration tests. However, in the literature, the mechanical aspect of the fuel cell systems is neglected. In this paper, a neural network modelling approach for the mechanical nonlinear behaviour of a proton exchange membrane (PEM) fuel cell system is proposed. An experimental set is designed for this purpose: a fuel cell system in operation is subjected to random and swept-sine excitations on a vibrating platform in three axes directions. Its mechanical response is measured with three-dimensional accelerometers. The raw experimental data are exploited to create a multi-input and multi-output (MIMO) model using a multi-layer perceptron neural network combined with a time regression input vector. The model is trained and tested. Results from the analysis show good prediction accuracy. This approach is promising because it can be extended to further complex applications. In the future, the mechanical fuel cell system controller will be implemented on a real-time system that provides an environment to analyse the performance and optimize mechanical parameters design of the PEM fuel system and its auxiliaries.     

Haemodynamics in the mouse aortic arch computed from MRI-derived velocities at the aortic root

Mice are widely used to investigate atherogenesis, which is known to be influenced by stresses related to blood flow. However, numerical characterization of the haemodynamic environment in the commonly studied aortic arch has hitherto been based on idealizations of inflow into the aorta. Our purpose in this work was to numerically characterize the haemodynamic environment in the mouse aortic arch using measured inflow velocities, and to relate the resulting shear stress patterns to known locations of high- and low-lesion prevalence. Blood flow velocities were measured in the aortic root of C57/BL6 mice using phase-contrast MRI. Arterial geometries were obtained by micro-CT of corrosion casts. These data were used to compute blood flow and wall shear stress (WSS) patterns in the arch. WSS profiles computed using realistic and idealized aortic root velocities differed significantly. An unexpected finding was that average WSS in the high-lesion-probability region on the inner wall was actually higher than the WSS in the low-probability region on the outer wall. Future studies of mouse aortic arch haemodynamics should avoid the use of idealized inflow velocity profiles. Lesion formation does not seem to uniquely associate with low or oscillating WSS in this segment, suggesting that other factors may also play a role in lesion localization.     

Biosupported bimetallic Pd-Au nanocatalysts for dechlorination of environmental contaminants

Biologically produced monometallic palladium nanoparticles (bio-Pd) have been shown to catalyze the dehalogenation of environmental contaminants, but fail to efficiently catalyze the degradation of other important recalcitrant halogenated compounds. This study represents the first report of biologically produced bimetallic Pd/Au nanoparticle catalysts. The obtained catalysts were tested for the dechlorination of diclofenac and trichlorethylene. When aqueous bivalent Pd(II) and trivalent Au(III) ions were both added to concentrations of 50 mg L(-1) and reduced simultaneously by Shewanella oneidensis in the presence of H(2), the resulting cell-associated bimetallic nanoparticles (bio-Pd/Au) were able to dehalogenate 78% of the initially added diclofenac after 24 h; in comparison, no dehalogenation was observed using monometallic bio-Pd or bio-Au. Other catalyst-synthesis strategies did not show improved dehalogenation of TCE and diclofenac compared with bio-Pd. Synchrotron-based X-ray diffraction, (scanning) transmission electron microscopy and energy dispersive X-ray spectroscopy indicated that the simultaneous reduction of Pd and Au supported on cells of S. oneidensis resulted in the formation of a unique bimetallic crystalline structure. This study demonstrates that the catalytic activity and functionality of possibly environmentally more benign biosupported Pd-catalysts can be improved by coprecipitation with Au.