Mrigank Mauli Dwivedi

Dielectric and Ion Transport Studies in [PVA: LiC2H3O2]: Li2Fe5O8 Polymer Nanocomposite Electrolyte System

The present work deals with the findings on optical and ion transport behavior in a ferrite-doped polymer nanocomposite electrolyte system, namely, [(100 − x) PVA + xLiC2H3O2]: yLiFe5O8. This polymer electrolyte system has been characterized by SEM, DSC, IR and C-V measurements. The addition of filler seems to disturb the crystalline nature of the host matrix while the doping of salt shows a similar structure, but with a separate entity in SEM images. DSC studies reflect the interaction of the salt/filler with polymer with a change in morphology of the composite system. These results are well-corroborated by IR data. The effect of salt or filler in the enhancement of the a.c. conductivity of nanocomposite polymer electrolyte (NCPE) as well as dielectric relaxation behavior has been investigated with the help of impedance spectroscopy data. The a.c. conductivity of nanocomposite polymer electrolytes is seen to be best described by the universal power law.

Effect of Plasticizers on Structural and Dielectric Behaviour of [PEO

Improvements in ion transport property of polyethylene-oxide- (PEO-) based polymer electrolytes have been investigated, using different types of plasticizers. The effects of single and coupled plasticizers [i.e., EC, (EC

Study of structural and dielectric behaviour on carbon nano tube dispersed {xPVF: (1 − x)CH3COONH4} electrolyte

In the present work, improvement in ion transport property of polyvinyl formal (PVF)-based nanocomposite polymer electrolytes has been studied upon dispersal of multiwall carbon nanotube (MWCNT) filler. Nanocomposite polymer electrolyte (NCPE) films of xPVF: (1 − x)CH3COONH4 (ammonium acetate) were prepared by solution cast technique. The formation of nanocomposite has been ascertained by X-ray diffraction (XRD) pattern, which also shows that doping of salt increases amorphousness through polymer salt complexation. Changes in surface morphology have been observed in optical microscopy and Scanning Electron Microscopic (SEM) images. Variation of dielectric constant, dielectric loss, tangent loss and modulus spectra with the change in frequency and temperature were studied with the aid of impedance spectroscopy.

Effect of Different Filler Groups on Ionic Behavior of PVdF Gel Electrolyte System

In the present work, improvement of ion transport property in poly vinylidene fluoride (PVdF)based polymer electrolytes, have been investigated using different groups of fillers. The effect of filler, on structural and electrical behavior of electrolyte was studied by XRD and impedance spectroscopy. Improvement in amorphous nature and ionic conductivity has been observed for PVdF based polymer electrolytes dispersed with different filler particles. Argond Plot shows dispersive nature of relaxation time and hopping mechanism appears to be responsible for ionic conduction of the composite polymer electrolyte.

Performance of ferrite fillers on electrical behavior of polymer nanocomposite electrolyte

Dispersal of nanofillers in polymer electrolytes have shown to improve the ionic properties of Polyethylene oxide (PEO)-based polymer electrolytes in recent times. The effects of different nanoferrite fillers (i.e., Al–Zn ferrite, Mg–Zn ferrite, and Zn ferrite) on the electrical transport properties have been studied here on the composite polymer electrolyte system. The interaction of salt/filler with electrolyte has been investigated by XRD studies. SEM image and infrared spectral studies give an indication of nanocomposite formation. In conductivity studies, all electrolyte systems are seen to follow universal power law. Composition dependence (with ferrite filler) gives the maximum conductivity in [93PEO–7NH4SCN]: X ferrite (where X = 2% in Al–Zn ferrite, 1% Mg–Zn ferrite, and 1% Zn ferrite) system.

Silicon bioavailability in exocarp of Cucumis sativus Linn.

Abstract Scanning electron microscopy (SEM) and electron probe micro-analyzer (EPMA) techniques have been used to detect the silicon bioavailability in the exocarp of warty cucumber surface. Warts appear at the time of anthesis and are remnant part of spines/trichomes which on further fruit maturation abscised from the exocarp. Results of EPMA and phytolith analysis clearly revealed that the surface of exocarp (fruit) of Cucumis sativus Linn. containing warts has greater quantity of silicon as compared to the other part of the fruit. Besides silicon, some other elements were also found, on the fruit exocarp and its surrounding area. The other elements are magnesium (Mg), aluminum (Al), phosphorus (P), sulfur (S), potassium (K), calcium (Ca), iron (Fe), nickel (Ni), copper (Cu), and sodium. The percentage of silica is highest followed by Ni, Ca, Al, P, Mg, Fe, S, Cu, K, and Cl. Thus, this study clearly demonstrates that Cucumis sativus Linn. fruits which are used as salads and appetizers on daily basis are loaded with silicon and other useful elements and possess numerous health benefits.

Synthesis and characterisation of PVdF-{(NH 4 ) 2 [C 4 H 8 (COO) 2 ]}: CNT gel electrolyte for Lt fuel cell application

In the present work, improvement of ion transport property in poly (vinylidene) fluoride (PVdF) - based polymer electrolytes for the use of low temperature fuel cell application have been investigated using CNT as fillers. The effect of filler, on structural and electrical behavior of electrolyte were studied by different experimental tools namely, XRD, Optical microscopy, impedance spectroscopy, and dielectric relaxation measurement. Improvement in amorphous nature and ionic conductivity has been observed for PVdF based polymer electrolytes dispersed with CNT filler particle. Dielectric plots show dispersive nature of relaxation time and hopping mechanism appears to be responsible for ionic conduction of the nanocomposite polymer electrolyte.

Synthesis and characterization of PVdF/ PEO blend based polymer electrolyte for DSSCs application

A blend of poly (vinyldiene fluoride) and PEO hybrid composite film was prepared via sol gel technique. The properties of the blend was studied, by morphological measurement such that optical microscopy and SEM image. It show that the change in crystalline structure of the blend composite system. This is an indication of the less interaction between PVdF and PEO. The electrical properties shows the effect of die as the increases in conductivity as compared to the pristine polymer electrolyte.

Geophysical and Experimental Petrological Studies of the Earth’s Interior

Seismo-tomographic studies, reveal the presence of two major discontinuities inside the earth: Mohorovicic discontinuity (occurring 35–45 km below the continents and 10–15 km below the ocean) and the other is Guttenberg-Reichert discontinuity, present 2860 km below the surface. These two discontinui ties divide the earth into, a) crust, b) mantle and c) core. There is also a low velocity discontinuity (Conrad, 10–15 km below the continental crust; not globally observed). Drilling of up to 13 km in Kola Peninsula, Russia across Conrad, shows the presence of sub-parallel faults causing intense shearing and re-equilibration to lower grade metamorphic rocks. Phase equilibria studies on olivine, Mg-Fe pyroxenes, diopsides, garnet, (Mg, Fe)O under P-T conditions similar to upper and lower mantle conditions suggest that the discontinuity at 313 km can be correlated with orthopyroxene ⇔ high pressure clinopyroxene (Mg, Fe)SiO3 phase transformation, but those at 410, 520 at 660 km have been attributed to structural changes of olivine ⇔ wadsleyite, wadsleyite ⇔ ringwoodite and akimotite ⇔ perovskite, respectively. The discontinu ity at 720 and 1200 km are considered to be due to conversion of MgSiO3 (majorite) to MgSiO3 (perovskite) and stishovite (rutile structure) to a SiO2 polymorph having PbO2 or CaF2-like structure. The discontinuity at 1700 km may be due to conversion of cubic Ca-perovskite to tetragonal Ca-perovskite structure, and that at 2740 km at the beginning of D″ layer may be due to transformation of perovskite to post-perovskite structure. The ultra low velocity zone (ULVZ) below 2870 km is due to the presence of liquid iron core. Studies at megabar and high temperatures reveal that the solid iron core, has a hexagonal close-packed structure.