Cubic Polynomial Maps with Periodic Critical Orbit, Part II: Escape Regions

The parameter space $\mathcal{S}_p$ for monic centered cubic polynomial maps with a marked critical point of period $p$ is a smooth affine algebraic curve whose genus increases rapidly with $p$. Each $\mathcal{S}_p$ consists of a compact connectedness locus together with finitely many escape regions, each of which is biholomorphic to a punctured disk and is characterized by an essentially unique Puiseux series. This note will describe the topology of $\mathcal{S}_p$, and of its smooth compactification, in terms of these escape regions. It concludes with a discussion of the real sub-locus of $\mathcal{S}_p$.Comment: 51 pages, 16 figure

Overview on Photocatalytic and Electrocatalytic Pretreatment of Industrial Non-Biodegradable Pollutants and Pesticides

Electrochemical and photochemical catalytic pretreatments were studied on diverse non-biodegradable industrial or toxic pollutants using different catalysts. This approach turned out also to be useful to degrade recalcitrant industrial waste waters markedly enhancing the biodegradability and biocompatibility of the treated effluents. In the case of p-toluenesulfonate, a completely non-biodegradable material from the dye industry, the TiO2 photocatalytic material applied for two hours affected total dearomatization allowing efficient subsequent biological degradation. A photochemical-biological flow reactor has been built to attain full mineralization of large volumes of diluted solutions of this xenobiotics as found in polluted water reservoirs. Fenton and photo-Fenton systems have been extensively studied in the abatement of the highly soluble Orange azo-dyes. They induce rapid destructive and low cost degradation of these textile dyes comparable to flocculation/coagulation techniques

Inactivation of bacteria under visible light and in the dark by Cu films. Advantages of Cu-HIPIMS-sputtered films

Introduction: The Cu polyester thin-sputtered layers on textile fabrics show an acceptable bacterial inactivation kinetics using sputtering methods. Materials and methods: Direct current magnetron sputtering (DCMS) for 40s of Cu on cotton inactivated Escherichia coli within 30min under visible light and within 120min in the dark. For a longer DCMS time of 180s, the Cu content was 0.294% w/w, but the bacterial inactivation kinetics under light was observed within 30min, as was the case for the 40-s sputtered sample. Results and discussion: This observation suggests that Cu ionic species play a key role in the E. coli inactivation and these species were further identified by X-ray photoelectron spectroscopy (XPS). The 40-s sputtered samples present the highest amount of Cu sites held in exposed positions interacting on the cotton with E. coli. Cu DC magnetron sputtering leads to thin metallic semi-transparent gray-brown Cu coating composed by Cu nanoparticulate in the nanometer range as found by electron microscopy (EM). Cu cotton fabrics were also functionalized by bipolar asymmetric DCMSP. Conclusion: Sputtering by DCMS and DCMSP for longer times lead to darker and more compact Cu films as detected by diffuse reflectance spectroscopy and EM. Cu is deposited on the polyester in the form of Cu2O and CuO as quantified by XPS. The redox interfacial reactions during bacterial inactivation involve changes in the Cu oxidation states and in the oxidation intermediates and were followed by XPS. High-power impulse magnetron sputtering (HIPIMS)-sputtered films show a low rugosity indicating that the texture of the Cu nanoparticulate films were smooth. The values of R q and R a were similar before and after the E. coli inactivation providing evidence for the stability of the HIPIMS-deposited Cu films. The Cu loading percentage required in the Cu films sputtered by HIPIMS to inactivate E. coli was about three times lower compared to DCMS films. This indicates a substantial Cu metal savings within the preparation of antibacterial film

Cover and Hitting Times of Hyperbolic Random Graphs

We study random walks on the giant component of Hyperbolic Random Graphs (HRGs), in the regime when the degree distribution obeys a power law with exponent in the range (2, 3). In particular, we focus on the expected times for a random walk to hit a given vertex or visit, i.e. cover, all vertices. We show that up to multiplicative constants: the cover time is n(log n) 2 , the maximum hitting time is n log n, and the average hitting time is n. The first two results hold in expectation and a.a.s. and the last in expectation (with respect to the HRG). We prove these results by determining the effective resistance either between an average vertex and the well-connected “center” of HRGs or between an appropriately chosen collection of extremal vertices. We bound the effective resistance by the energy dissipated by carefully designed network flows associated to a tiling of the hyperbolic plane on which we overlay a forest-like structure

Cover and Hitting Times of Hyperbolic Random Graphs

We study random walks on the giant component of Hyperbolic Random Graphs (HRGs), in the regime when the degree distribution obeys a power law with exponent in the range $(2,3)$. In particular, we focus on the expected times for a random walk to hit a given vertex or visit, i.e. cover, all vertices. We show that up to multiplicative constants: the cover time is $n(\log n)^2$, the maximum hitting time is $n\log n$, and the average hitting time is $n$. The first two results hold in expectation and a.a.s. and the last in expectation (with respect to the HRG). We prove these results by determining the effective resistance either between an average vertex and the well-connected "center" of HRGs or between an appropriately chosen collection of extremal vertices. We bound the effective resistance by the energy dissipated by carefully designed network flows associated to a tiling of the hyperbolic plane on which we overlay a forest-like structure.Comment: 34 pages, 2 figures. To appear at the conference RANDOM 202

Preparation, Testing and Characterization of Doped TiO2 Active in the Peroxidation of Biomolecules under Visible Light

Doped TiO2 samples using different preparative procedures were synthesized using either urea or thiourea leading to N- or S-doped TiO2. Photocatalytic peroxidation and oxidation (mineralization) of phosphatidylethanolamine (PE) lipid with doped TiO2 were carried out under light irradiation λ > 410 nm. The formation of conjugated double bonds in PE molecules was followed to detect the formation of peroxy radicals (peroxidation index) under light excitation (λ > 410 nm) when doped TiO2 was used. The kinetics of CO2 production was monitored during the mineralization of PE. Colored TiO2 powders were studied in detail by different and complementary physicochemical techniques. The band gap energies of colored TiO2 were determined by diffuse reflectance spectroscopy (DRS). The visible absorption shoulder of TiO2 was observed to follow Urbach\u27s law. The variation of the transient decay after 354 nm laser pulse excitation does not correlate with the different N− and S−TiO2 doping levels introduced by the addition of urea or thiourea. This suggests that the states (recombination centers or traps) introduced by the doping are not effective in varying the decay kinetics within the nanosecond and microsecond time scale. Elemental analysis shows comparable amounts of S- and N-doping of TiO2 when thiourea is used as dopant. X-ray diffraction reveals no rutile in S−TiO2 samples heated to 600 °C, suggesting that the addition of sulfur precludes rutilization during sample crystallization. X-ray photoelectron spectroscopy (XPS) of the S−TiO2 samples confirms the preferential localization of S on the 20 topmost layers of S−TiO2 upon calcination at 500 °C for 2 h

Inactivation of bacteria under visible light and in the dark by Cu films. Advantages of Cu-HIPIMS-sputtered films

The Cu polyester thin-sputtered layers on textile fabrics show an acceptable bacterial inactivation kinetics using sputtering methods. Direct current magnetron sputtering (DCMS) for 40 s of Cu on cotton inactivated Escherichia coli within 30 min under visible light and within 120 min in the dark. For a longer DCMS time of 180 s, the Cu content was 0.294% w/w, but the bacterial inactivation kinetics under light was observed within 30 min, as was the case for the 40-s sputtered sample. This observation suggests that Cu ionic species play a key role in the E. coli inactivation and these species were further identified by X-ray photoelectron spectroscopy (XPS). The 40-s sputtered samples present the highest amount of Cu sites held in exposed positions interacting on the cotton with E. coli. Cu DC magnetron sputtering leads to thin metallic semi-transparent gray-brown Cu coating composed by Cu nanoparticulate in the nanometer range as found by electron microscopy (EM). Cu cotton fabrics were also functionalized by bipolar asymmetric DCMSP. Sputtering by DCMS and DCMSP for longer times lead to darker and more compact Cu films as detected by diffuse reflectance spectroscopy and EM. Cu is deposited on the polyester in the form of Cu2O and CuO as quantified by XPS. The redox interfacial reactions during bacterial inactivation involve changes in the Cu oxidation states and in the oxidation intermediates and were followed by XPS. High-power impulse magnetron sputtering (HIPIMS)-sputtered films show a low rugosity indicating that the texture of the Cu nanoparticulate films were smooth. The values of R (q) and R (a) were similar before and after the E. coli inactivation providing evidence for the stability of the HIPIMS-deposited Cu films. The Cu loading percentage required in the Cu films sputtered by HIPIMS to inactivate E. coli was about three times lower compared to DCMS films. This indicates a substantial Cu metal savings within the preparation of antibacterial films

Recent Developments in Accelerated Antibacterial Inactivation on 2D Cu-Titania Surfaces under Indoor Visible Light

This review focuses on Cu/TiO2 sequentially sputtered and Cu-TiO2 co-sputtered catalytic/photocatalytic surfaces that lead to bacterial inactivation, discussing their stability, synthesis, adhesion, and antibacterial kinetics. The intervention of TiO2, Cu, and the synergic effect of Cu and TiO2 on films prepared by a colloidal sol-gel method leading to bacterial inactivation is reviewed. Processes in aerobic and anaerobic media leading to bacterial loss of viability in multidrug resistant (MDR) pathogens, Gram-negative, and Gram-positive bacteria are described. Insight is provided for the interfacial charge transfer mechanism under solar irradiation occurring between TiO2 and Cu. Surface properties of 2D TiO2/Cu and TiO2-Cu films are correlated with the bacterial inactivation kinetics in dark and under light conditions. The intervention of these antibacterial sputtered surfaces in health-care facilities, leading to Methicillin-resistant Staphylococcus Aureus (MRSA)-isolates inactivation, is described in dark and under actinic light conditions. The synergic intervention of the Cu and TiO2 films leading to bacterial inactivation prepared by direct current magnetron sputtering (DCMS), pulsed direct current magnetron sputtering (DCMSP), and high power impulse magnetron sputtering (HIPIMS) is reported in a detailed manner

Oxygen Distribution of Fluorine-doped Tin Oxide Films Coated on Float Glass along Depth Before and After Heat Treatment

Fluorine-doped tin oxide (FTO) films were deposited on float glass to create low-emissivity glass (low-E glass) by atmospheric pressure chemical vapor deposition (APCVD). Heat treatments were carried out to assess its antioxidant properties. The surface morphology, crystal structure, and the oxygen and tin concentrations in the FTO films were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), Auger electron spectrometer (AES), and X-ray photoelectron spectroscopy (XPS), respectively. The results indicated that the electrical properties determined by the four-point probe method remained constant up to 600 degrees C with increasing temperature. The FTO films exhibited nonstoichiometry with a ratio of [O]/[Sn] >2 on the top surface and <2 in the film. The sheet resistance of the film strongly depended on the oxygen concentration on the film surface. When the heating temperature reached 700 degrees C, the sheet resistance increased rapidly from 9.4 to 86.7 Omega/square with a concomitant increase in the oxygen concentration on the top surface