Thermoplastic blend of polyaniline with polyvinyl chloride‐nitrile rubber

Polyaniline doped with (±)‐camphor sulfonic acid was blended with polyvinyl chloride/nitrile rubber. The thermoplastic blend was characterized for its conductivity, mechanical and dynamic mechanical properties, and microwave response. The blend was found to be compatible in nature. Loss component of relative permittivity increased with polyaniline content. Storage modulus increased with polyaniline content, whereas tan δ showed decline. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1217–1222, 2006     

Pure exciplex electroluminescence in blended film of small organic molecules

3,6-diarylcarbazole derivatives, 3,6-di-(p-cyanophenyl)-N-hexylcarbazole (CNHC) and 3,6-di-(p-acetylphenyl)-N-hexylcarbazole (ANHC) were synthesized, characterized and energy levels determined. Steady state fluorescence of these molecules showed blue emission in thin films. Blends of these molecules with N,N′-diphenyl-N,N′-(bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD) showed exciplex emission as the dominant one. Single layer organic light emitting devices (OLEDs) of CNHC, ANHC and their blends with TPD were fabricated using ITO as anode and Ca as cathode. The blend film devices showed pure exciplex electroluminescence.     

Conductive ceramic coating on polyacrylonitrile–vinyl chloride (modacrylic) discontinuous fibers via electroless deposition

Lead dioxide has electrical conductivity that is comparable to that of some of the metals. As a result like copper and nickel, lead dioxide can be deposited on non-conducting materials like polymers and ceramics using spontaneous and low cost deposition technique such as electroless deposition. This paper deals with development of conductive modacrylic fibers by coating them with lead dioxide via electroless deposition. The fibers so obtained will be used as additive in the lead-acid battery to improve its life and specific energy.     

A NEW LOW-REYNOLDS-NUMBER TURBULENCE MODEL FOR PREDICTION OF TRANSITION ON GAS TURBINE BLADES

A new low-Reynolds-number (LRN) turbulence model is developed for the prediction of transition. In the definition of the LRN functions in the new model, only local quantities are used so that the model potentially can be used for a wide range of flows. The performance of the new model in predicting boundary layer transition is demonstrated by reference to a wide range of experimental data for boundary layers with free-stream turbulence and pressure gradient.     

Numerical simulation of electroosmotic flow

We have developed a numerical scheme to simulate electroosmotic flows in complicated geometries. We studied the electroosmotic injection characteristics of a cross-channel device for capillary electrophoresis. We found that the desired rectangular shape of the sample plug at the intersection of the cross-channel can be obtained when the injection is carried out at high electric field intensities. The shape of the sample plug can also be controlled by applying an electric potential or a pressure at the side reservoirs. Flow induced from the side channels into the injection channel squeezes the streamlines at the intersection, thus giving a less distorted sample plug. Results of our simulations agree qualitatively with experimental observations.     

A versatile implicit iterative approach for fully resolved simulation of self-propulsion

We present a computational approach for fully resolved simulation of self-propulsion of organisms through a fluid. A new implicit iterative algorithm is developed that solves for the swimming velocities of the organism with prescribed deformation kinematics. A solution for the surrounding flow field is also obtained. This approach uses a constraint-based formulation of the problem of self-propulsion developed by Shirgaonkar et al. [1]. The approach in this paper is unlike the previous work [1] where a fractional time stepping scheme was used. Fractional time stepping schemes, while efficient for moderate to high Reynolds number problems, are not suitable for zero or low Reynolds number problems where the inertia term in the governing equation is absent or negligible. In such cases the implicit iterative algorithm presented here is more appropriate. We validate the method by simulating self-propulsion of bacterial flagellum, jellyfish (Aurelia aurita), and larval zebrafish (Danio rerio). Comparison of the computational results with theoretical and experimental results for the test cases is found to be very good.     

Magnetic properties and magnetoelectric effect in Ni0.8Co0.1Cu0.1Fe2O4 + PbZr0.2Ti0.8O3 composites

Composites with compositions x (Ni_0.8Co_0.1Cu_0.1Fe₂O₄) + (1−x) PbZr_0.2Ti_0.8O₃ (x-mole fraction varies as 0.15, 0.25, 0.35 and 0.45) were prepared by standard ceramic method. The presence of constituent phases, namely ferrite and the ferroelectric were confirmed by X-ray diffraction. The structural analyses were carried out using the obtained powder pattern X-ray data. The porosity of the samples was calculated and the values obtained lie between 10% to 19%. To date, the variations in the magnetic properties with variation in ferrite phase in composites and thereby its influence on magnetoelectric effect is not yet reported. The saturation magnetization (Ms) and magnetic moment (η_B) in Bohr magneton were calculated for all the composites. The static value of magnetoelectric voltage coefficient (dE/dH) was measured as a function of intensity of magnetic field. The maximum value of ME coefficient was observed for a composite with 35% ferrite + 65% ferroelectric phase.     

Grain-size control in Ti-48Al-2Cr-2Nb with yttrium additions

A gas-atomized (GA) prealloyed powder of the Ti-48Al-2Cr-2Nb intermetallic and 1.6 wt pct Y were mechanically alloyed (MA) and hot isostatically pressed (hipped) to produce a fully dense nanocrystalline material. Mechanical alloying of the as-blended powder for 16 hours resulted in the formation of a disordered fcc phase. Hipping of the alloy powder produced a single-phase nanocrystalline TiAl intermetallic, containing a distribution of 20 to 35-nm-sized Al₂Y₄O₉ particles. The formation of oxide particles occurred by the chemical combination of Al and Y with oxygen, which entered as a contaminant during milling. Oxide particles increased the hardness of the intermetallic compound and minimized grain growth even at 0.8 T _m , where T _m is the melting point of the compound.