In this work, the porosity of plasma electrolytic oxidation (PEO)-based coatings on Al- and Mg-based substrates was studied by two imaging techniques-namely, SEM and computer microtomography. Two approaches for porosity determination were chosen; relatively simple and fast SEM surface and cross-sectional imaging was compared with X-ray micro computed tomography (microCT) rendering. Differences between 2D and 3D porosity were demonstrated and explained.
View Article and Find Full Text PDFThe principal possibility to grow layered double hydroxide (LDH) at ambient pressure on plasma electrolytic oxidation (PEO) treated magnesium alloy AZ91 in the presence of chelating agents is demonstrated for the first time. It avoids hydrothermal autoclave conditions, which strongly limit wide industrial application of such coating systems, and the presence of carbonate ions in the electrolyte, which lead to the formation of "passive" non-functionalizable LDH. A combination of chelating agents (sodium diethylenetriamine-pentaacetate (DTPA) and salicylate) were introduced to the treatment solution.
View Article and Find Full Text PDFJ Environ Sci Health A Tox Hazard Subst Environ Eng
June 2015
Continuous aerobic biodegradation of 4-NP, 3-NP and 2-NP mixture was monitored in a packed bed reactor in simulated wastewater with a mixed microbial culture immobilized on expanded slate. Substrate loading was varied by increasing the concentration of one isomer while keeping the other two at constant levels, all at a constant residence time of 60 min. At large concentrations, all of the individual NP isomers suppressed the degradation rates of the other isomers at steady state; however, the observed patterns and threshold concentrations were different for all three substrates.
View Article and Find Full Text PDFJ Environ Sci Health A Tox Hazard Subst Environ Eng
September 2013
Aerobic biodegradation of individual mononitrophenols (4-, 3- and 2-NPs) and their mixture in simulated wastewater was investigated in a packed-bed bench scale bioreactor continuously operated in a flow mode, with a mixed microbial culture adsorbed on expanded slate. Under a low, suboptimal hydraulic retention time (HRT) of 30 min the reactor removed more than 3 g.L(-1).
View Article and Find Full Text PDFInternal carotid artery pseudoaneurysm is a rare complication of deep neck infections. The authors report the case of a 17-year-old male who presented to the Department of Otorhinolaryngology with an acute tonsillitis requiring tonsillectomy. Four weeks after the surgery the patient was readmitted because of progressive swallowing, trismus, and worsening headache.
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