Band head spin assignment of superdeformed bands in Hg isotopes through power index formula

The power index formula has been used to obtain the band head spin(I_0) of all the superdeformed(SD) bands in Hg isotopes. A least squares fitting approach is used. The root mean square deviations between the determined and the observed transition energies are calculated by extracting the model parameters using the power index formula. Whenever definite spins are available, the determined and the observed transition energies are in accordance with each other. The computed values of dynamic moment of inertia J~((2)) obtained by using the power index formula and its deviation with the rotational frequency is also studied. Excellent agreement is shown between the calculated and the experimental results for J~((2)) versus the rotational frequency. Hence, the power index formula works very well for all the SD bands in Hg isotopes expect for ~(195)Hg(2, 3, 4).     

In-cylinder engine flow measurement using stereoscopic molecular tagging velocimetry (SMTV)

The stereoscopic molecular tagging velocimetry (SMTV) technique is used to obtain the multiple point measurement of an instantaneous three-component velocity field inside the cylinder of an internal combustion (IC) engine assembly. A novel image processing technique is implemented to obtain the velocity data. The technique has the advantage that it eliminates the geometric details required to obtain the three components of the velocity field. The procedure involves two major steps: (i) calibration process and (ii) data acquisition and reduction. Cycle-to-cycle variations of the three-component velocity field and out-of-plane vorticity are presented inside an engine cylinder. Preliminary results show that cycle-to-cycle variations are more prominent in the velocity component perpendicular to the tumble plane, as opposed to the in-plane components. Such new insights will help better understand the details of these flows and further improve CFD models for IC engines.     

Design and Optimization of Nonlinear Tapers using Particle Swarm Optimization

In this paper the design and optimization of a nonlinear diameter taper, connecting the output section of a gyrotron cavity to the uniform output waveguide section, is presented. The design of a nonlinear taper of a 42 GHz, 200 kW CW gyrotron operating in the TE_0,3 cavity mode with axial output collection has been taken as a case study. The taper synthesis has been carried out considering a raised cosine type of nonlinear taper and the analysis is done using a dedicated scattering matrix code. In addition, an improved particle swarm optimization - an evolutionary optimization - algorithm is used for the design optimization of this nonlinear taper. The optimum design of the taper shows the effectiveness of the presented method.     

Lattice dynamics of strontium tungstate

We report here measurements of the phonon density of states and the lattice dynamics calculations of strontium tungstate (SrWO₄). At ambient conditions this compound crystallizes to a body-centred tetragonal unit cell (space group I4₁/a) called scheelite structure. We have developed transferable interatomic potentials to study the lattice dynamics of this class of compounds. The model parameters have been fitted with respect to the experimentally available Raman and infra-red frequencies and the equilibrium unit cell parameters. Inelastic neutron scattering measurements have been carried out in the triple-axis spectrometer at Dhruva reactor. The measured phonon density of states is in good agreement with the theoretical calculations, thus validating the interatomic potential developed.      

Laminar separation bubble on an Eppler 61 airfoil

Laminar separation bubble that occurs on the suction side of the Eppler 61 airfoil at Re=46000 is studied. The incompressible flow equations are solved using a stabilized finite element method. No turbulence model is used. The variation of the bubble length and its location, with the angle of attack (α), is studied in detail. An abrupt increase in the lift coefficient is observed at α∼4.5°. It is found to be related to a sudden decrease in the separation bubble length at the trailing edge of the airfoil. Significant differences are observed in the results from the 2D and 3D computations. Stall is observed in 3D simulations, but is found to be absent in 2D. The laminar bubble, which fails to reattach in 3D for α>14°, continues to reattach for α as large as 20° in the 2D computations. Reynolds stress calculations in both 2D and 3D indicate the extent to which the outer flow is affected by the presence of bubble. It is found that the Reynolds stress components ${\over{u{^\prime}}{v{^\prime}}}$ and ${\over{u{^\prime}}{w{^\prime}}}$ are of comparable order of magnitude indicating that spanwise fluctuations are significant. The effect of the time window used to compute the time‐averaged aerodynamic coefficients is studied. The time‐averaged and root mean square (rms) value of the aerodynamic coefficients are calculated for both 2D and 3D computations and compared with the previously published experimental results. The 3D computations show good agreement with the earlier data. The variation of the rms value of the aerodynamic coefficients with angle of attack shows certain peaks. The cause of their appearance is investigated. The effect of Reynolds number is studied. The increase in Re at α=10° is found to reduce the bubble length and cause it to move closer to the leading edge. Copyright © 2009 John Wiley & Sons, Ltd.     

Enhanced Performance of CNT‐doped Imine Based Receptors as Fe(III) Sensor Using Potentiometry and Voltammetry

A highly sensitive and selective potentiometric and voltammteric assay for the detection of Fe³⁺ using (E)‐3‐((2‐(2‐(2‐aminoethylamino) ethylamino) ethylimino)methyl)‐4H‐chromen‐4‐one (IFE(III)) ionophore was developed. To demonstrate the ion‐to‐electron transfer ability of MWCNT, these were incorporated in the ion‐selective membrane and response characteristics of Fe³⁺ electrode was compared with those of the traditional ion selective electrode. The electrode showed an improved Nernstian slope, lower detection limit, response time of less than 5 s and working in a pH range of 3.0 to 8.0. Differential pulse voltammetric studies were performed for IFE(III)‐Fe³⁺ complex in DMSO solvent medium at glassy carbon (GC) electrode. A linear relationship between the cathodic peak current and concentration of Fe³⁺ was observed in the range of 1.6×10^?5 to 4.4×10^?5 mol/L with a detection limit of 5.2×10^?8 mol/L. The electrode shows remarkable selectivity for Fe³⁺ ions over alkali, alkaline earth, transition and heavy metal ions. The optimized electrode was successfully applied for the determination of Fe³⁺ ion in different real‐life samples using potentiometric technique. Theoretical calculations were used to support the complexation behavior of Fe³⁺ with IFE(III).     

Estimation of vanadium in different oxidation states

Summary In the present investigations, the different oxidation states of vanadium have been estimated volumetrically in mixtures with the help of visual indicators.

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Zusammenfassung Die verschiedenen Wertigkeitsstufen des Vanadiums wurden volumetrisch in Mischungen bestimmt. Zur Endpunktanzeige dienten visuelle Indicatoren.

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Thanks of the authors are due to the C.S.I.R. authorities for providing a Research Fellowship to one of them (R.K.M.).     

A self-aligning ultrasound sensor for detecting foreign bodies in glass containers

This paper introduces the principle and design of an ultrasonic transducer system with auto-alignment mechanism. The proposed system is used for detecting foreign bodies (FBs) in beverage containers. Variation in reflection amplitude is analyzed as a function of the ultrasound beam incident angle to beverage container surface. It is concluded that there exists a quadratic relationship between the strength of the reflected signal and the incident angle. Furthermore, a calculation for effective angular increment for searching the normal of a curved surface is introduced. Experiments conducted using the prototype demonstrated that FBs are detectable in various juices. Experiments also observed some false echo signals that occur due to curved container surface. Threshold in confined time region is therefore set to ensure no fail of detection in low signal to noise ratio. This design is also applicable to non-destructive inspection for metal canned food.