Filtering procedures for flow in heterogeneous porous media: numerical results

This paper focuses on heterogeneous soil permeabilities and on the impact their resolution has on the solution of the piezometric head equation. The method of coarse graining is proposed in order to filter the piezometric head equation on arbitrary support scales: Large scale fluctuations of the permeabilities are resolved, whereas small scale fluctuations are smoothed by a spatial filtering procedure. The filtering procedure is performed in Fourier space with the aid of a low-frequency cut-off function. In the filtered equations, the impact of the small scale variability is modeled by scale dependent effective permeabilities which are determined by additional differential equations. The additional differential equations are equivalent to the piezometric head equation on cells which are solved numerically by using the software toolbox UG. The numerical results are compared with the theoretical results derived in Attinger 2001.     

Preparation and characterisation of chromium-doped cobalt oxide spinel thin films

Thin films of cobalt-based oxide spinel were prepared by pulsed spray evaporation chemical vapour deposition (PSE-CVD), and doping with chromium was systematically investigated up to a Cr/Co ratio of 0.096, corresponding to a stoichiometry of Co_3−x Cr _x O₄ with x = 0.00–0.26. The effect of doping concentration on the structure, assessed by X-ray diffraction and Raman scattering, and on the optical and electrical properties of the oxide films was investigated. Single-phase spinel could be preserved for stoichiometries below x = 0.22. The influence of Cr-doping on the band gap energies and on the electrical conductivity was determined, and the obtained results were exploited to discuss the cationic site occupations. The influence of Cr doping was complemented by the investigation of the surface catalytic reactivity towards the oxidation of dichloromethane.     

Discovery and Biophysical Evaluation of First Low Nanomolar Hits Targeting CYP125 of M. tuberculosis

Tuberculosis, which is predominantly caused by Mycobacterium tuberculosis (Mtb), is still the most lethal bacterial infection with 1.5 million casualties in 2014. Moreover, the fact that the appearance of resistant mutants and long‐term treatment are coupled with economic problems in developing countries hampers an efficient therapy. Interference with the essential cholesterol metabolism of Mtb could be a promising novel strategy to fight Mtb infections. CYP125, a P450 enzyme in Mtb, has been shown to play an important role in this metabolic pathway. For this reason, we used a combined screening approach involving surface plasmon resonance spectroscopy and a heme coordination assay to identify new CYP125 binders by employing a focused P450‐inhibitor library. We identified the first hits with high affinity and favorable ligand efficiencies. Furthermore, frontrunner compounds also showed selectivity toward CYP121 specific to Mtb and required for its survival. To date, these are the first compounds targeting CYP125 with low nanomolar affinity.     

Die Direktreduktion von Feineisenerzen in Druckwirbelschichtreaktoren: Experimentelle Untersuchungen und morphologische Betrachtung zur Übertragung auf industrielle Prozesse

In industrial plants it was observed that the operating conditions in the prereduction stage have a significant effect on the final reduction degree. A laboratory scale, pressurized fluidized bed reactor was developed according to the concept of chemical similarity to perform experiments similar to industrial operating conditions. With this set-up, temperatures up to 900°C and operating pressures up to 10⁵ Pa absolute can be realized. Numerous experiments with H₂-rich reduction gas according to the FINMET^®-process and CO-rich reduction gas according to the FINEX^®-process were carried out. Temperature, residence time and gas composition were varied. The samples were analyzed and morphologically evaluated. The influence of the operating conditions in the prereduction stage on the final reduction degree was reproduced, studied and confirmed by morphological investigations.     

混凝土引气剂的再活化潜能(第2部分)

4.2外加剂对砂浆和混凝土中气泡形成的影响4.2.1稠度、抗压强度和气泡特征参数在初步试验中,调整外加剂到合适掺量,测定稠度、28d抗压强度以及气泡特征参数(见第1部分表3)。其中7个砂浆和3个混凝土试样满足所需的干硬性稠度,其压实系数在1.27～1.34之间。由引气剂和原材料引起的系统差异并不明显。砂浆试件28d抗压强度为47.0～52.5MPa,与3个道路混凝土试件的抗压强度相当。主要的差异是由含气量变化造成的。对硬化砂浆的检测显示,气泡间距系数在0.14～0.20mm之间(第     

Kinetics of Escherichia coli inactivation employing hydrogen peroxide at varying temperatures,pH and concentrations

The effectiveness of hydrogen peroxide on the destruction of planktonic cells of Escherichia coli at different temperatures, pH and sanitizer concentrations was studied. Inactivation kinetics of E. coli exhibited a clear dependence on hydrogen peroxide concentration, pH and temperature. A Weibullian mathematical model successfully described the inactivation curves. Quantitative kinetic results obtained allowed to identify various combinations H₂O₂ concentration–pH–temperature for 5-log cycles reduction of E. coli. Flow cytometry analysis revealed induced H₂O₂ cytoplasm membrane damage. TEM observations indicated that H₂O₂ treatment resulted in rupture of outer and cytoplasm membranes and a more uniform granularity.     

3 MV hypervelocity dust accelerator at the Colorado Center for Lunar Dust and Atmospheric Studies

A hypervelocity dust accelerator for studying micrometeorite impacts has been constructed at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) at the University of Colorado. Based on the Max-Planck-Institu?t fu?r Kernphysik (MPI-K) accelerator, this accelerator is capable of emitting single particles of a specific mass and velocity selected by the user. The accelerator consists of a 3 MV Pelletron generator with a dust source, four image charge pickup detectors, and two interchangeable target chambers: a large high-vacuum test bed and an ultra-high vacuum impact study chamber. The large test bed is a 1.2 m diameter, 1.5 m long cylindrical vacuum chamber capable of pressures as low as 10(-7) torr while the ultra-high vacuum chamber is a 0.75 m diameter, 1.1 m long chamber capable of pressures as low as 10(-10) torr. Using iron dust of up to 2 microns in diameter, final velocities have been measured up to 52 km/s. The spread of the dust particles and the effect of electrostatic focusing have been measured using a long exposure CCD and a quartz target. Furthermore, a new technique of particle selection is being developed using real time digital filtering techniques. Signals are digitized and then cross-correlated with a shaped filter, resulting in a suppressed noise floor. Improvements over the MPI-K design, which include a higher operating voltage and digital filtering for detection, increase the available parameter space of dust emitted by the accelerator. The CCLDAS dust facility is a user facility open to the scientific community to assist with instrument calibrations and experiments.