“…For OLPT conduction model, s can be written as where Rω = 14α[ln(1ωτ0)-WHOKβT]+{[ln(1ωτ0)-WHOKβT]2+8αrpWHOKβT} is hopping length at angular frequency ω (tunneling distance), r p is polaron radius, W HO is the activation energy associated with ionic charge transfer between overlapping sites and α is the inverse localization length. 26 Figure 19.Variation of frequency components with temperature of RSHC and DSHC. (RSHC: Raw Sunn Hemp Composite; DSHC: Dewaxed Sunn Hemp Composite.…”
Section: Dielectric Properties Analysis Of Compositesmentioning
confidence: 99%
“…(tunneling distance), r p is polaron radius, W HO is the activation energy associated with ionic charge transfer between overlapping sites and is the inverse localization length. 26…”
Section: Frequency Dependence Conductivity Analysismentioning
confidence: 99%
“…Sun hemp is bast fiber kind and owned by the class of Fabaceae family. The presence of high content of cellulose (70-78%) in sunn hemp leads to high tensile strength (400-1000 MPa) and stiffness (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35). 6 Sunn hemp has a very high aspect ratio of 500-600 and exhibits very low density of 1.4-1.6 g/cm 3 .…”
Present investigation is aimed on chemically modified of Sunn Hemp (Crotalaria juncea) fiber for composite fabrication. An increment in cellulose crystallinity with crystallite size is observed from X-ray diffraction study. The signature of impurities removal and an uneven surface are confirmed from Fourier Transmission Infrared Spectroscopy and Field Emission Scanning Electron Microscopy. Afterwards, both raw sunn hemp-reinforced fiber composite and dewaxed sunn hemp fiber-reinforced composite were fabricated using hand lay out method and the mechanical as well as dielectric properties of composite are studied. A better mechanical strength is found in DSHC which may attribute to rough surface and increased cellulose crystallinity through dewaxing process that promoted a fine interfacial bonding between fiber and matrix. Dielectric constants and losses are found to be less in dewaxed sunn hemp fiber-reinforced composite in comparison to raw sunn hemp-reinforced fiber composite due to decrease of water polar groups, which lead to lessening the effect of space charge polarization by treatment. Complex impedance and modulus study revealed the presence of single relaxation process in both systems. Lower ac conductivity value is observed in dewaxed sunn hemp fiber-reinforced composite due to decreasing of conducting polar OH groups. As a whole, the effort is established to correlate the mechanical and dielectric properties with fine structural parameters of the fiber.
“…For OLPT conduction model, s can be written as where Rω = 14α[ln(1ωτ0)-WHOKβT]+{[ln(1ωτ0)-WHOKβT]2+8αrpWHOKβT} is hopping length at angular frequency ω (tunneling distance), r p is polaron radius, W HO is the activation energy associated with ionic charge transfer between overlapping sites and α is the inverse localization length. 26 Figure 19.Variation of frequency components with temperature of RSHC and DSHC. (RSHC: Raw Sunn Hemp Composite; DSHC: Dewaxed Sunn Hemp Composite.…”
Section: Dielectric Properties Analysis Of Compositesmentioning
confidence: 99%
“…(tunneling distance), r p is polaron radius, W HO is the activation energy associated with ionic charge transfer between overlapping sites and is the inverse localization length. 26…”
Section: Frequency Dependence Conductivity Analysismentioning
confidence: 99%
“…Sun hemp is bast fiber kind and owned by the class of Fabaceae family. The presence of high content of cellulose (70-78%) in sunn hemp leads to high tensile strength (400-1000 MPa) and stiffness (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35). 6 Sunn hemp has a very high aspect ratio of 500-600 and exhibits very low density of 1.4-1.6 g/cm 3 .…”
Present investigation is aimed on chemically modified of Sunn Hemp (Crotalaria juncea) fiber for composite fabrication. An increment in cellulose crystallinity with crystallite size is observed from X-ray diffraction study. The signature of impurities removal and an uneven surface are confirmed from Fourier Transmission Infrared Spectroscopy and Field Emission Scanning Electron Microscopy. Afterwards, both raw sunn hemp-reinforced fiber composite and dewaxed sunn hemp fiber-reinforced composite were fabricated using hand lay out method and the mechanical as well as dielectric properties of composite are studied. A better mechanical strength is found in DSHC which may attribute to rough surface and increased cellulose crystallinity through dewaxing process that promoted a fine interfacial bonding between fiber and matrix. Dielectric constants and losses are found to be less in dewaxed sunn hemp fiber-reinforced composite in comparison to raw sunn hemp-reinforced fiber composite due to decrease of water polar groups, which lead to lessening the effect of space charge polarization by treatment. Complex impedance and modulus study revealed the presence of single relaxation process in both systems. Lower ac conductivity value is observed in dewaxed sunn hemp fiber-reinforced composite due to decreasing of conducting polar OH groups. As a whole, the effort is established to correlate the mechanical and dielectric properties with fine structural parameters of the fiber.
“…When (s) is both frequency and temperature dependent, along with a broad minima followed by an increase of (s) with further increasing temperature, the OLPT model can be suggested. [42] As its name implies the overlapping large polaron tunneling is based on the displacement of the polaron (defined as being the moving charge and the distorted network that surrounds it) over a spatial compound extent larger than the interatomic spacing. For this model, the variation of the AC conductivity in frequency is given by: [43][44][45][46]…”
The aim of this work is to elaborate the LiNaWO4 compound, using the solid state method, then to characterize it using an XR study which confirms that it crystallizes in the orthorhombic system with P222 as space group and with the lattice parameters a = 12.82 Å, b = 17.49 Å, c = 7.25 Å and α = β = γ = 90°. The differential scanning calorimetry (DSC) shows two endothermic peaks at T1 = 388 K and T2 = 500 K. The first peak is detected by the dielectric study, attributed to a phase transition from a ferroelectric phase to a paraelectric one, while the second peak indicates the presence of a phase transition, confirmed later by the result of the electrical study. All modes pertaining to vibrations of WO42− tetrahedral appear in the Raman spectrum. Moreover, its impedance response is modeled by a single cell formed by a parallel combination of R//C//CPE, i.e. the response of our compound is that of the grain. The variation of the σg and σdc, as a function of temperature, confirms the phase transition observed in the calorimetric study at T2. The conduction mechanism in the two phases indicates that the first phase (I) is described by the CBH model and the second phase by the OLPT model.
“…In OLPT model, the power exponent depend both on frequency and temperature. Initially had dropped to a minimum value with increasing temperature and then escalated with further increase in temperature [51]. The ac conductivity in OLPT model is usually given by following equation [52];…”
The conventional ceramic route has been used to prepare the La-doped Ba2SnO4 samples by heat-treatment at 1000oC and sintered at 1250oC. The phase identification was carried out using XRD and found to be single phase up to 4 atoms %. The solubility of La at Ba-site were further reconfirmed using FTIR and Raman analysis. The AC conductivity spectra of all samples follow universal Johnscher’s power law; however, the thermal dependence of suggest Arrhenius type conduction within the sample. Further, the scaled conductivity and frequency at all temperatures superimposes on a single master curve, indicates the invariance of conduction mechanism. The impedance spectroscopy studies suggest the major contribution of grain in the conduction and relaxation. The present material could be potentially used in semiconductor device, UV-detector, and mixed ionic and electronic conductor (MIECs) by utilizing absorption states and thermo-curves as metastable state.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
