p-Chloro Substituted Cinnamohydroxamic Acids as Analytical Reagent for Cerium. Spectrophotometric Determination with N-Phenyl-p-Chlorocinnamohydroxamic Acid

A selective and sensitive method for the solvent extraction and spectrophotometric determination of cerium(IV) with N-phenyl- p-chlorocinnamohydroxamic acid (N-p-p-Cl-CHA) has been described. It forms a red colored complex with cerium and the complex can be extracted with chloroform at pH 9 to 10. The effect of the pH, reagent concentration, extraction time, stability of color, diverse ions and stoichiometry of the complex is discussed

Application of p-Substituted Cinnamohydroxamic Acids to the Spectrophotometric Determination of Molybdenum(VI)

The formation of greenish yellow coloured complex o.E molybdenum( VI) with nine new p-substituted cinnamohydroxamic acids have been studied. This study shows that the molybdenum complex of nine new hydroxamic acids have molar absorptivities between 3.5 x 104 and 1.1 x 105 1 moi-1 cm-1• This value is considerably large as compared to value obtained by benzohydroxamic acid, N-phenylbenzohydroxamic acid and N-p-chlorophenylbenzo- hydroxamic acidi.2• A rapid extraction and spectrophotometric method for the determination of molybdenum is described, employing the most promising of these reagents, N-p-tolyl-p-methoxycinnamohydroxamic acid

Application of p-Substituted Cinnamohydroxamic Acids to the Spectrophotometric Determination of Molybdenum(VI)

The formation of greenish yellow coloured complex o.E molybdenum( VI) with nine new p-substituted cinnamohydroxamic acids have been studied. This study shows that the molybdenum complex of nine new hydroxamic acids have molar absorptivities between 3.5 x 104 and 1.1 x 105 1 moi-1 cm-1• This value is considerably large as compared to value obtained by benzohydroxamic acid, N-phenylbenzohydroxamic acid and N-p-chlorophenylbenzo- hydroxamic acidi.2• A rapid extraction and spectrophotometric method for the determination of molybdenum is described, employing the most promising of these reagents, N-p-tolyl-p-methoxycinnamohydroxamic acid

The dependence of the estimated luminosities of ULX on spectral models

Data from {\it Chandra} observations of thirty nearby galaxies were analyzed and 365 X-ray point sources were chosen whose spectra were not contaminated by excessive diffuse emission and not affected by photon pile up. The spectra of these sources were fitted using two spectral models (an absorbed power-law and a disk blackbody) to ascertain the dependence of estimated parameters on the spectral model used. It was found that the cumulative luminosity function depends on the choice of the spectral model, especially for luminosities $> 10^{40}$ ergs/s. In accordance with previous results, a large number ($\sim 80$) of the sources have luminosities $> 10^{39}$ ergs/s (Ultra-Luminous X-ray sources) with indistinguishable average spectral parameters (inner disk temperature $\sim 1$ keV and/or photon index $\Gamma \sim 2$) with those of the lower luminosities ones. After considering foreground stars and known background AGN,we identify four sources whose minimum luminosity exceed $10^{40}$ ergs/s, and call them Extremely Luminous X-ray sources (ELX). The spectra of these sources are in general better represented by the disk black body model than the power-law one. These ELX can be grouped into two distinct spectral classes. Two of them have an inner disk temperature of $< 0.5$ keV and hence are called ``supersoft'' ELX, while the other two have temperatures $\gtrsim 1.3$ keV and are called ``hard'' ELX. The estimated inner disk temperatures of the supersoft ELX are compatible with the hypothesis that they harbor intermediate size black holes, which are accreting at $\sim 0.5$ times their Eddington Luminosity. The radiative mechanism for hard ELX, seems to be Inverse Comptonization, which in contrast to standard black holes systems, is probably saturated.Comment: Accepted for publication in Astrophysical Journal. 9 pages. Complete long Tables 4 and 5 are given as tab4.tex and tab5.tex separatel

Thermal Analysis of Small Re-Entry Probe

The Small Probe Reentry Investigation for TPS Engineering (SPRITE) concept was developed at NASA Ames Research Center to facilitate arc-jet testing of a fully instrumented prototype probe at flight scale. Besides demonstrating the feasibility of testing a flight-scale model and the capability of an on-board data acquisition system, another objective for this project was to investigate the capability of simulation tools to predict thermal environments of the probe/test article and its interior. This paper focuses on finite-element thermal analyses of the SPRITE probe during the arcjet tests. Several iterations were performed during the early design phase to provide critical design parameters and guidelines for testing. The thermal effects of ablation and pyrolysis were incorporated into the final higher-fidelity modeling approach by coupling the finite-element analyses with a two-dimensional thermal protection materials response code. Model predictions show good agreement with thermocouple data obtained during the arcjet test

Synthesis of Al and Ag nanoparticles through ultra-sonic dissociation of thermal evaporation deposited thin films for promising clinical applications as polymer nanocomposite

Nanoparticles (NPs) having well-defined shape, size and clean surface serve as ideal model system to investigate surface/interfacial reactions. Ag and Al NPs are receiving great interest due to their wide applications in bio-medical field, aerospace and space technology as combustible additives in propellants and hydrogen generation. Hence, in this study, we have synthesized Ag and Al NPs using an innovative approach of ultra-sonic dissociation of thin films. Phase and particle size distributions of the Ag and Al NPs have been determined by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thin film dissociation/dissolution mechanism, hence conversion into NPs has been characterized by SEM- scanning electron microscope. EDXA & ICPMS have been performed for chemical analysis of NPs. Optical properties have been characterized by UV-Vis and PL spectroscopy. These NPs have also been investigated for their anti-bacterial activity against Escherichia coli bacteria. To the best of our knowledge, this is the first time when NPs has been synthesized by ultra-sonic dissociation of thin films. As an application, these NPs were used further for synthesis of nanocomposite polymer membranes, which show excellent activity against bio film formation

Fermionic bright soliton in a boson-fermion mixture

We use a time-dependent dynamical mean-field-hydrodynamic model to study the formation of fermionic bright solitons in a trapped degenerate Fermi gas mixed with a Bose-Einstein condensate in a quasi-one-dimensional cigar-shaped geometry. Due to a strong Pauli-blocking repulsion among spin-polarized fermions at short distances there cannot be bright fermionic solitons in the case of repulsive boson-fermion interactions. However, we demonstrate that stable bright fermionic solitons can be formed for a sufficiently attractive boson-fermion interaction in a boson-fermion mixture. We also consider the formation of fermionic solitons in the presence of a periodic axial optical-lattice potential. These solitons can be formed and studied in the laboratory with present technology.Comment: 7 pages, 7 ps figure

Stable circulation modes in a dual-core matter-wave soliton laser

We consider a model of a matter-wave laser generating a periodic array of solitary-wave pulses. The system, a general version of which was recently proposed in Ref. [5], is composed of two parallel tunnel-coupled cigar-shaped traps (a reservoir and a lasing cavity), solitons being released through a valve at one edge of the cavity. We report a stable lasing mode accounted for by circulations of a narrow soliton in the cavity, which generates an array of strong pulses (with 1,000 - 10,000 atoms in each, the array's duty cycle ~ 30%) when the soliton periodically hits the valve.Comment: J. of Physics B: At. Mol. Opt. Physics, in pres

Characterization of silicon nanowire by use of full-vectorial finite element method.

We have carried out a rigorous H-field-based full-vectorial modal analysis and used it to characterize, more accurately, the abrupt dielectric discontinuity of a high index contrast optical waveguide. The full-vectorial H and E fields and the Poynting vector profiles are described in detail. It has been shown through this work that the mode profile of a circular silicon nanowire is not circular and also contains a strong axial field component. The single-mode operation, vector field profiles, modal hybridness, modal ellipticity, and group velocity dispersion of this silicon nanowire are also presented