We report here structural and IeV characteristics of ZnO varistor with Fe2O3 nanoparticles additions (
200 nm). It was found that the addition of Fe does not influence the wurtzite structure of ZnO ceramics, while the average grain size was affected. Interestingly, the nonlinear regionwas clearly observed in the IeV characteristics of the samples with Fe ¼ 2.5%, 5% and 10%. Whereas, two nonlinear regions were only observed with further increase of Fe addition above 10% (30% and 50%). Although the values of non-linear coefficient are decreased by the additions of Fe, the breakdown field could be increased up to 7900 V/cm. Furthermore, the electrical conductivity was improved by increasing Fe up to 10%, followed by a decrease with further increase of Fe up to 50%. These results were discussed in terms of Fe2O3 nanosize grains which were formed and localized at the grain boundaries of ZnO ceramics.

We report here the paraconductivity of ErBa2Cu3

We report here on the eect of annealing time, in air and at 800C for time periods of (6{30 h), on the uctuation induced excess conductivity
 in Bi2

We report here on the eect of annealing time, in air and at 800C for time periods of (6{30 h), on the uctuation induced excess conductivity
 in Bi2

Sodium dodecyl sulfate, a biological membrane mimetic, can be used to study the conversion of globular proteins into amyloid fibrils in vitro. Using multiple approaches, the effect of SDS was examined on stem bromelain (SB), a widely recognized therapeutic protein. SB is known to exist as a partially folded intermediate at pH 2.0, situation also encountered in the gastrointestinal tract (its site of absorption). In the presence of sub-micellar SDS concentration (500-1000 μM), this intermediate was found to exhibit great propensity to form large-sized β-sheeted aggregates with fibrillar morphology, the hall marks of amyloid structure. We also observed inhibition of fibrillation by two naphthalene-based compounds, ANS and bis-ANS. While bis-ANS significantly inhibited fibril formation at 50 μM, ANS did so at relatively higher concentration (400 μM). Alcohols, but not salts, were found to weaken the inhibitory action of these compounds suggesting the possible involvement of hydrophobic interactions in their binding to protein. Besides, isothermal titration calorimetry and molecular docking studies suggested that inhibition of fibrillation by these naphthalene derivatives is mediated not just through hydrophobic forces, but also by disruption of π-π interactions between the aromatic residues together with the inter-polypeptide chain repulsion among negatively charged ANS/bis-ANS bound SB.

The effect of sintering temperature on ZnO varistor properties is investigated in the range of 700–1400 1C. The increase of sintering temperature does not influence the well-known peaks related to hexagonal wurtzite structure of ZnO ceramics, whereas the average grain size is increased from (1.08 to 2.1 mm).With increasing sintering temperature up to 1200 1C, the nonlinear region is clearly observed in the I–V characteristics, whereas this region is completely absent only for the sample sintered at 1400 1C. As the sintering temperature increased, the breakdown field decreased over a wide range from 2838.7 to 6.41 V/cm, while the nonlinear coefficient is increased in the range of (23.86–47.76). Furthermore, the barrier height decreased from 1.76 to 0.974 eV, whereas electrical conductivity is improved. On the other hand, the optical band gap is gradually decreased in the range of 3.08–2.70 eV with increasing sintering temperature. These results showed a strong correlation between sintering temperature and the properties of ZnO ceramic varistor.

We report here structural, surface morphology, mechanical, and current–voltage characteristics of Zn1

Structural,mechanicalandsuperconductingpropertiesofBi2Sr2Ca1xYxCu2Oy superconductorswith various x values(0.00rxr0.50) areinvestigatedbyX-raydiffraction,scanningelectronmicroscopy, Vickershardnessandresistivitymeasurements.ItisfoundthatthereplacementofCa2þ by Y3þ does not influencethephasepurityofBi:2212whilelatticeparameters,orthorhombicdistortion,surface morphology,oxygencontentandholecarrierperCuion(P)areaffected.Furthermore,thecritical temperatures Tc are increasedbyincreasing Y contentupto0.30,followedbyadecreasewithfurther increaseof Y contentupto0.50.Thevaluesof Tc are 88,94,101,104and501 K for x¼0.00,0.075,0.15, 0.30 and0.50,respectively.Similarbehaviorisobtainedfortheabsolutevaluesoftruehardness Ht and surface energy g against Y contentwhiletheoppositebehaviorisrecordedfortheholecarrierperCu ion (P),deducedfrom Tc values,against Y content.Similarbehaviorisobtainedfortheabsolutevalues of truehardness Ht and surfaceenergy g against Y content.Theseresultsarediscussedintermsof possiblereasonsforsuppressionofsuperconductivityby Y substitutionattheCasiteintheBi:2212 superconductingsystem.

Mechanical and magnetic properties of the ZnO/Fe2O3 ceramic varistors have been examined by using mechanical analyzer, digital microhardness tester and vibrating sample magnetometer. The initial stress–strain behavior is found to be linear (elastic) then becomes nonlinear (plastic deformation) without reaching the failure limit up to the maximum available stress (0.07 MPa). The compressive elastic modulus varies between 0.2 and 0.8 MPa with Fe addition up to 0.50. Furthermore, an approximately monotonically linear decrease in VHN with increasing Fe content up to 50% has been observed for all applied loads, which closely resembles the behavior of the true hardness and the surface energy. The magnetic measurements revealed an antiferromagnetic to paramagnetic to transition for all Fe doped samples. The Fe free sample showed paramagnetic behavior down to 2 K. The Neel temperature moderately increased from 18 K at 0.05% Fe to 25 K at 0.5% Fe. The magnetization (M) versus applied magnetic field (H) did not reach saturation for all samples up to 9 Tesla. The saturated magnetization (per Fe contents) is low and found to decreases linearly at a rate of (35 emu/g-Fe) in a clear manifestation of the strengthening of the antiferromagnetic exchange interaction with increasing Fe contents.

In this paper, the Kelvin-Helmholtz instability of viscous incompressible magnetic fluid fully saturated porous media is achieved through the viscous potential theory. The flow is considered to be through semi-permeable boundaries above and below the fluids through which the fluid may either be blown in or sucked out, in a direction normal to the main streaming direction of the fluid flow. An oblique magnetic field, mass, heat transfer, and surface tension are present across the interface. Through the linear stability analysis, a general dispersion relation is derived and the natural curves are plotted. Therefore, the linear stability condition is discussed in some depth. In view of the multiple time scale technique, the Ginzburg–Landau equation, which describes the behavior of the system in the nonlinear approach, is obtained. The effects of the orientation of the magnetic fields on the stability configuration in linear, as well as nonlinear approaches, are discussed. It is found that the Darcy’s coefficient for the porous layers plays a stabilizing role. The injection of the fluids at both boundaries has a stabilizing effect, in contrast with the suction at both