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Nanostructured membranes based on poly(vinyl alcohol) (PVA) and chitosan (CS) weight ratio of PVA:CS (80:20), mixed with 40% phosphoric acid (H3PO4) and finally doped with nanoporous niobium oxide (Nb2O5) at different concentrations, were prepared by solution casting method. The ionic transport, structural, and thermal properties were studied by different techniques. Thermal analysis shows the glass...
A polymer based on poly (vinyl alcohol) (PVA) and chitosan (CS) with a weight ratio of 80:20 was prepared by solvent casting processes, and the effect of H3PO2 was investigated. Thermal analysis shows miscibility of the two polymer amorphous phases since a single Tg was located between those of the individual components and the melting point of the crystalline phase was depressed to 189 °C. It was...
The main function of multilevel inverters is to synthesize a desired AC voltage output starting from several input levels of direct current voltage. There are several circuit topologies and modulation strategies to generate the desired output voltage of an inverter, among which stands out the traditional Sine Pulse Width Modulation (SPWM) technique with several variants. Phase Disposition (PD), Phase...
Cellular networks are currently facing severe traffic overload, and different approaches to alleviate this problem are currently being studied. An attractive solution that does not demand major modifications to deployed infrastructure is to offload part of the cellular traffic to complementary networks. Based on that, this paper investigates the feasibility of low bit-rate H.264 video streaming offloading...
The phase behaviour of K 3 H(SeO 4 ) 2 (TKHSe) above room temperature has been studied by differential scanning calorimetric (DSC), thermogravimetric analysis (TGA), simultaneous thermogravimetric and mass spectroscopy analysis (TG-MS), impedance spectroscopy (IS) and X-ray powder diffraction (XRD). Our results show that the previously claimed superionic...
The dispersion curves of the dielectric response for KHSeO4 were obtained in the radio frequency range at several isotherms below the fast proton conducting phase (T < 415 K). The results reveal a distinct dielectric relaxation at low frequency, which is about 682 Hz at 320 K, and then, it shifts to higher frequencies (∼10 kHz) as the temperature increases. The fmax vs. reciprocal T shows an activated...
Low-frequency conductivity measurements have been performed in solid polymer electrolyte composites based on the anhydrous PVOH–LiH2PO4–Al2O3 system. A typical power law dependency in the real part of the conductivity, at higher frequencies, of the form ωn is observed, with an exponent n that depends on the alumina content and nearly independent of temperature. An analysis of the frequency dependence...
The business model concept has only recently been discussed in the research literature. Some authors have pointed out that it is a second-order construct and have examined its theoretical underpinnings as a cognitive mechanism for opportunity perception and identification, using it as a tool to systematically approach the analysis of the beliefs and decisions that entrepreneurs use in building their...
In the present paper, the ionic conductivity and the dielectric relaxation properties on the poly(vinyl alcohol)-CF3COONH4 polymer system have been investigated by means of impedance spectroscopy measurements over wide ranges of frequencies and temperatures. The electrolyte samples were prepared by solution casting technique. The temperature dependence of the sample’s conductivity was modeled by Arrhenius...
We report on electrical relaxation measurements of (1 − x)NH4H2PO4-xTiO2 (x = 0.1) composites by admittance spectroscopy, in the 40-Hz–5-MHz frequency range and at temperatures between 303 and 563 K. Simultaneous thermal and electrical measurements on the composites identify a stable crystalline phase between 373 and 463 K. The real part of the conductivity, σ’, shows a power-law frequency dependence...
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