X-Ray fluorescence analysis of thulium oxide for rare earth impurities

A wavelength dispersive X-ray fluorescence spectrometric method has been developed for the analysis of thulium oxide to determine the neighbouring rare earth impurities. The sample is taken in oxalate form and the analysis is done on a Philips PW 1220 spectrometer with a LiF (200) crystal. The detection limit for holmium, lutetium and yttrium is 0.002%, for dysprosium and erbium 0.005% and for, ytterbium it is 0.01%. The precision at each concentration of the standards and the theoretical detection limits have been calculated. Intensity correction factors for the line overlaps have been determined.     

A lower bound on the error in dimensionality reduction resulting from projection onto a restricted subspace

We obtain the lower bound on a variant of the common problem of dimensionality reduction. In this version, the dataset is projected on to a k dimensional subspace with the property that the first k-1 basis vectors are fixed, leaving a single degree of freedom in terms of basis vectors.     

Long-Range Behavior of Dual-Restricted QCD Vacuum

We analyze the geometrical structure of the local non-Abelian gauge theory in terms of the magnetic symmetry, using the resemblance between the non-Abelian gauge formulations and Einstein's theory of gravitation in a higher dimensional unified space. The mathematical foundation of dual QCD in fiber bundle form is then discussed and used for the analysis of the important problem of color confinement in QCD. The associated Lagrangian formulation in magnetic gauge is shown to lead to dual dynamics due to the emergence of the topological charges of magnetic nature. The dynamical breaking of magnetic symmetry is shown to lead to the magnetic condensation of the QCD vacuum. A state of the dual superconductivity in the QCD vacuum is then shown to evolve which ultimately pushes the QCD vacuum to the confining phase. The flux tube structure of the magnetically condensed QCD vacuum is analyzed by computing the asymptotic string solutions of the field equations. The energy content of such confining structures is computed and analyzed in terms of its logarithmic and linear nature.     

Ion transport and solid state battery studies on a new silver molybdate superionic glass system: x[0.75AgI: 0.25AgCl]: (1-x)[Ag2O: MoO3]

Preparation, material characterization, ion transport and battery discharge characteristic studies are reported for a new silver molybdate glass system: x[0.75AgI: 0.25AgCl]: (1-x)[Ag₂O: MoO₃], where 0<x<1 in molar weight fraction. The traditional host AgI has been replaced by an alternate compound: “a quenched [0.75AgI: 0.25 AgCl] mixed system/solid solution”. Electrical conductivity (σ), ionic mobility (μ) and mobile ion concentration (n) measurements were carried out as a function of “x”. The composition: 0.8[0.75AgI: 0.25AgCl]: 0.2[Ag₂O: MoO₃] exhibited the highest conductivity (∼ 6×10⁻³ S·cm⁻¹) at room temperature and has been referred to as ‘optimum conducting composition (OCC)’. The compositional variation of “μ” and “n” revealed that the enhancement in the room temperature conductivity of OCC is predominantly due to the increase in mobile ion concentration. The XRD and DSC analysis on OCC indicated the formation of glassy phase with partial presence of unreacted polycrystalline phase of the host salt. The temperature dependence of various ionic transport parameters viz. “σ”, “μ”, “n” and ionic transference number (t_ion) were carried out on the OCC and the results have been discussed on the basis of theoretical models suggested for superionic glasses. In addition to this, solid state batteries were fabricated using OCC as electrolyte and discharge characteristics were studied under varying load conditions.     

Elemental analysis of horse hair by optical emission spectroscopy

A spectrographic method is developed for the simultaneous determination of trace elements in horse hair. The quantitative estimates of elements Ag, Al, B, Ca, Cu, Fe, Mg, Mn, Na, P, Pb, Si, Ti, v, and Zn are reported and the precision of determination for some elements is given.     

Determination of rare earth impurities in cerium dioxide and oxalate by X-ray fluorescence technique

A method for the determination of lathanum, praseodymium, neodymium and samarium oxides in cerium dioxide has been developed. The sample in the oxalate form is mixed with the binding material (boric acid) in the ratio 1∶1 pressed to form a double layer pellet over a boric acid backing pellet and irradiated by X-rays from a tungsten tube. The secondary X-rays are dispersed with a LiF (200) crystal in a Philips PW 1220 semiautomatic X-ray fluorescence spectrometer. The intensity of fluorescent X-rays is measured by a flow proportional counter. The minimum determination limit is 0.01% for lanthanum and samarium oxides and 0.02% for praseodymium and neodymium oxides. The precision at each concentration of the standards and theoretical minimum determination limit for each element have been calculated.