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51.
Simona Maggini Elisa CappellettoFabrizio Girardi Wilma VaonaRosa Di Maggio 《Progress in Organic Coatings》2013
Silica based cellulose nanocomposites obtained from (3-mercaptopropyl)trimethoxysilane or vinyltrimethoxysilane and 3-butynoate-substituted zirconium-oxoclusters were prepared and their surface morphology, wettability, and thermo-mechanical properties were studied. The composites showed a hydrophobic surface, high strength, and resistance to thermal degradation and aging; in comparison to the untreated paper they required a higher temperature to activate combustion and generated less heat during all thermal processes. 相似文献
52.
Sarunas Varnagiris Jolanta Doneliene Simona Tuckute Jurate Cesniene Darius Milcius 《Polymer-Plastics Technology and Engineering》2018,57(13):1296-1302
Conventional expanded polystyrene can absorb moisture, which significantly degrades its properties. In the present study, it was demonstrated that SiO2 can be deposited on polystyrene beads before pre-expansion and molding steps. Under the applied test conditions, expanded polystyrene with nanocrystalline SiO2 additives had approximately 10% lower moisture adsorption and an 8.4% better resistance to deformation. Expanded polystyrene analysis suggested that the observed improvements were caused by the hydrophobic nature of nanocrystalline SiO2 and, even more importantly, because SiO2 acted as an amalgamation catalyst and significantly increased adhesion between the expanded polystyrene beads during the expanded polystyrene molding process. 相似文献
53.
54.
Influence of catalyst pretreatments on volatile organic compounds oxidation over gold/iron oxide 总被引:4,自引:0,他引:4
Simona Minic Salvatore Scir Carmelo Crisafulli Signorino Galvagno 《Applied catalysis. B, Environmental》2001,34(4):277-285
This paper reports a study on the influence of calcination pretreatments on the catalytic behaviour of the Au/iron oxide system towards the combustion of some representative volatile organic compounds (2-propanol, ethanol, methanol, acetone and toluene). The catalytic activity of Au/Fe2O3 samples towards the total oxidation to CO2 has been found to be strongly dependent on the catalyst pretreatment, decreasing on increasing the calcination temperature. On the basis of characterisation data (XPS, FT-IR, XRD, BET surface area) it has been proposed that the catalytic behaviour is related to the gold state and/or the iron oxide phase. It appears plausible to suggest that the gold oxidation state and/or the particle size play a key role in the catalytic combustion of volatile organic compounds. 相似文献
55.
Stefan M Marius S Hritcu L Lucian H Mihasan M Marius M Pricop D Daniela P Gostin I Irina G Olariu RI Romeo-Iulian O Dunca S Simona D Melnig V Viorel M 《Journal of materials science. Materials in medicine》2011,22(4):789-796
In the present study, we report enhanced antimicrobial properties of 29 and 23 nm silver nanoparticles (Ag NPs) obtained by
electrochemical synthesis in poly(amide-hydroxyurethane) media. Antibacterial activity assessed by disk diffusion method indicates
that silver nanoparticles produced inhibition zones for both Escherichia coli and Staphylococcus aureus depending on silver concentration. The bacterial growth curve performed in the presence of silver nanoparticles showed a
stronger antibacterial effect at lower concentrations than those described in the earlier reports. The effect was both dose
and size dependent and was more pronounced against Gram negative bacteria than Gram positive one. The smallest Ag NPs used
had a bactericidal effect resulting in killing E. coli cells. Scanning electron microscopy analysis indicated major damage and morphology changes of the silver nanoparticles treated
bacterial cells. The major mechanism responsible for the antibacterial effect probably consists in clusters formation and
nanoparticles anchorage to the bacterial cell surface. 相似文献
56.
Federico Aulenta Andrea Canosa Luigi De Roma Priscilla Reale Stefania Panero Simona Rossetti Mauro Majone 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(6):864-870
BACKGROUND: A bioelectrochemical process for trichloroethene (TCE) dechlorination was developed. In this new process, a solid‐state electrode polarized to ?450 mV versus the standard hydrogen electrode (SHE), in combination with a redox mediator (i.e., methyl viologen, MV) is employed as an electron donor for the microbial reductive dechlorination of TCE. In this study we compared the performance of the process with the redox mediator immobilized at the surface of electrodes or dissolved in the bulk liquid, using both a culture highly enriched in Desulfitobacterium spp., capable of dechlorinating TCE to cis‐dichloroethene (cis‐DCE), and a culture highly enriched in Dehalococcoides spp. capable of dechlorinating cis‐DCE to ethene. RESULTS: Short‐term potentiostatic (?450 mV versus SHE) experiments showed that TCE or cis‐DCE was dechlorinated both in the presence of soluble (500 µmol L?1) and immobilized MV. However, TCE or cis‐DCE dechlorination rates with MV‐modified electrodes were remarkably lower than with soluble MV. Both cultures produced significant amounts of H2 in the presence of electrically reduced, soluble MV, whereas no H2 was produced when the mediator was immobilized at the electrode surface, regardless of the potential applied to the electrode, in the range ?425 to ?500 mV versus SHE. CONCLUSIONS: The process, operated with modified electrodes, supports the microbial dechlorination of TCE to ethene. Immobilization not only allows retention of the mediator within the system, but also increases process efficiency by preventing bioelectrochemical H2 formation. On the other hand, strategies to increase dechlorination rates with modified electrodes need to be developed. Copyright © 2009 Society of Chemical Industry 相似文献
57.
Volker John Petr Knobloch Simona B. Savescu 《Computer Methods in Applied Mechanics and Engineering》2011,200(41-44):2916-2929
Stabilized finite element methods for convection-dominated problems require the choice of appropriate stabilization parameters. From numerical analysis, often only their asymptotic values are known. This paper presents a general framework for optimizing stabilization parameters with respect to the minimization of a target functional. Exemplarily, this framework is applied to the SUPG finite element method and the minimization of a residual-based error estimator, an error indicator, and a functional including the crosswind derivative of the computed solution. Benefits of the basic approach are demonstrated by means of numerical results. 相似文献
58.
Orthonasal or retronasal presentation of odorants evokes different responses. To study this phenomenon in depth, a stimulation technique has been developed that allows ortho- or retronasal presentation of chemosensory stimuli, the release of which is precisely controlled. Based on this technique studies have been conducted using psychophysical, electrophysiological, and imaging techniques. In conjunction with clinical data the results clearly suggest that there are differences in the perception of ortho- and retronasal stimuli. The basis for this phenomenon may be found in ideas by Mozell and colleagues with regard to odorant absorption across the mucosa which may determine activation of the olfactory epithelium. 相似文献
59.
60.
Surface and interface properties of functionalized polysulfones: Cell‐material interaction and antimicrobial activity 下载免费PDF全文
Quaternized polysulfones with different ionic chlorine content tested for biomedical applications were obtained by quaternization reaction of chloromethylated polysulfones with N,N‐dimethylethanolamine. The relationship between the different physical and chemical characteristics of these polymers and their biocompatible and antimicrobial properties was established for maximizing the selectivity and performance of these materials for biomedical applications. Therefore, topographic reorganization of the polysulfonic films induced by the type of nonsolvent in casting solutions of polymer significantly influences films morphology, depending on the charge density of polyelectrolytes, the hydrophilic/hydrophobic characteristics, as well as on the history of the formed films. Furthermore, the study of the adhesion of red blood cells and cohesion of platelets on the surface of quaternized polysulfone films, as well as analysis of antibacterial activity, using Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923 microorganisms, contribute to extending the possible applications of quaternized polysulfones as semipermeable membranes in biomedical domains. POLYM. ENG. SCI., 55:2184–2194, 2015. © 2015 Society of Plastics Engineers 相似文献