Preparation and characterization of magnetic polymeric microspheres based on styrene, divinylbenzene and vinyl acetate [Preparação e caracterização de microesferas poliméricas magnéticas à base de estireno, divinilbenzeno e acetato de vinila]
Castanharo J.A.,State University of Rio de Janeiro |
Mello I.L.,State University of Rio de Janeiro |
De S. Maria L.C.,State University of Rio de Janeiro |
Costa M.A.S.,State University of Rio de Janeiro |
And 2 more authors.
Polimeros | Year: 2012
Magnetic polymeric microspheres based on styrene (STY), divinylbenzene (DVB), vinyl acetate (VAc) and iron were prepared through suspension and semi-suspension polymerization. An investigation was made of the influence from the concentration of VAc added to the polymerization and the presence of iron on the properties of the polymeric particles. These particles were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA/DTGA), reflection optical microscopy (OM), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). Polymeric microspheres with magnetic properties based on styrene, divinylbenzene and vinyl acetate were obtained. These materials showed good control of the spheres morphology and aggregated iron particles throughout the microsphere surface. The greater yield of microspheres was found in the range of 288 μm. They also showed good magnetic properties (from 22.62 to 73.75 emu.g-1) with superparamagnetic behavior and good thermal stability (444 °C).
De Oliveira M.F.L.,State University of Rio de Janeiro |
De Oliveira M.G.,INT |
Leite M.C.A.M.,State University of Rio de Janeiro
Polimeros | Year: 2011
Nanocomposites of polyamide 6 and Claytone 40 organoclay were prepared with the melt intercalation technique using an internal mixer chamber coupled with roller type rotors. The addition of increasing amounts of Claytone 40 into the PA6 matrix was evaluated for the degree of dispersion, crystallinity, thermal and mechanical properties. The compositions were characterized with X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and mechanical properties. The diffraction patterns and microscope images suggest the formation of partially exfoliated or intercalated structures, which was associated with an increase in stress values and elastic modulus. The comparison of DSC and XRD results from the mixtures revealed changes in the behavior of crystalline structures, thus indicating that the PA6 crystallinity is correlated with the mechanical properties.
Sergio Bello S.,Instituto Nacional del Torax INT |
Haydee Chamorro R.,Instituto Nacional del Torax INT |
Andrea Barrientos R.,INT
Revista Chilena de Enfermedades Respiratorias | Year: 2013
In COPD patients, smoking worsens lung function and smoking cessation reduces the fall in FEV1 and all-cause of mortality. There is a high percentage of these patients who continues smoking despite the disease due to the high degree of dependence, low motivation to quit and association with depression and false beliefs, which hampers attempts to stop smoking and reduce their success. The smoker's treatment has two pillars: psychosocial intervention and pharmacological treatment. In COPD patients' psychosocial intervention should be especially intense, empathic and aimed at increasing motivation and self-efficacy, using Motivational Interviewing. In pharmacotherapy, first-line drugs are nicotine replacement (NRT), bupropion and varenicline. In patients with COPD, NRT is effective and may be combined passive delivery NRT with other active delivery. Bupropion has been used, with cost-effectiveness. Varenicline in patients with mild to moderate COPD has been effective. In brief therapies for smokers with COPD should be more intense, combining pharmacological and psychosocial treatment and maintained over time.
Parshin P.P.,RAS Research Center Kurchatov Institute |
Zemlyanov M.G.,RAS Research Center Kurchatov Institute |
Crystallography Reports | Year: 2011
The previous experimental data on the partial spectra of thermal atomic vibrations in icosahedral (Al 62Cu 25.5Fe 12.5) and decagonal (Al 71.3Ni 24Fe 4.7) quasicrystals have been used to perform a comparative analysis of the atomic dynamics features and determine the role that Al, Cu, Ni, and Fe atoms play in the formation of interatomic interaction in the alloys studied. A physical model of the decagonal quasicrystal structure is proposed. © Pleiades Publishing, Inc., 2011.
Mohammed E.,Hassan II University |
Mostafa B.,Networks Laboratory |
International Journal of Computer Science and Applications | Year: 2015
The IMS networks offer several advantages to telecom operators in terms of connectivity and deployment of new services. However, the multitude of supported access technologies poses significant challenges for QoS management. To this effect, The INQA approach (IMS Network QoS Architecture) provides innovative solutions for services supervision and monitoring, in real time. This allows identification of any QoS degradation, based in resource status. In this work we propose the integration of correction mechanisms and QoS restoration, based on eTOM processes and reports monitoring outcome of supervision operation. The work aims to set up an autonomous system for QoS correction, in IMS context. © Technomathematics Research Foundation.