Single column ion chromatography of ammonium ion,alkali metals and alkyl amines

Summary Comparative efficiencies of oxalic, dichloroacetic and sulfamic acids as eluents in ion chromatographic determination of ammonium ion, alkali ions and alkyl amines have been evaluated. In all cases these eluents compared favorably to the popular nitric acid eluent employed for the ion chromatography of these species. Sulfamic acid has been found to be particularly superior for the separation and quantitation of alkali ions and several alkyl amines in ppm and sub ppm range.     

Relative efficiencies of substituted aromatic monocarboxylic acids as eluents in ion chromatographic separation of inorganic and organic anions

The eluent strengths of para, ortho and meta substituted hydroxy-, nitro-, amino- and sulfobenzoic acids in single column ion chromatographic separations of inorganic and organic anions have been evaluated and compared with benzoic acid.o-Sulfobenzoic acid turns out to be a stronger and efficient eluent compared to others for the separation and determination of monovalent (Cl^–, NO ₂ ^– , Br^–, NO ₃ ^– ) and divalent (SO ₄ ^2– , SeO ₄ ^2– , S₂O ₃ ^2– , S₂O ₆ ^2– ) inorganic anions. In addition it also functions as an appropriate mobile phase for the detection and quantification of some substituted benzoate ions in an aqueous medium.     

Simultaneous analysis of selenate and selenite by single-column ion chromatography

Summary A rapid, selective and sensitive method has been developed for the simultaneous determination of selenate [Se(VI)] and selenite [Se(IV)] at trace levels by single-column ion chromatography. p-Hydroxybenzoic acid (4 mM) at pH 8.0 was used as the eluent. A low capacity resin-based anion-exchange column was employed for the separation with conductometric detection for quantification. The method requires minimal sample pretreatment. Resolution (R_s) between Se(VI)/Se(IV) was 6.76. Chloride, nitrate and sulfate did not interfere with selenium separation. The detection limits for Se(VI) and Se(IV) were 0.06 μg/ml and 0.110 μg/ml, respectively. The relative standard deviation using a 500-μl loop was 0.90 to 1.86% for Se(VI) and Se(IV), respectively. The method was applied to analyze seleniferous soil samples.     

Spectrophotometric determination of iron(II) after separation by adsorption of its complex with 3-(4-phenyl-2-pyridyl)-5,6-diphenyl-1,2,4-triazine and tetraphenylborate on microcrystalline naphthalene

Trace iron(II) is determined spectrophotometrically after adsorption of its ternary complex with 3-(4-phenyl-2-pyridyl)-5,6-diphenyl-1,2,4-triazine and tetraphenylborate on microcrystalline naphthalene at pH 5.1–7.4. The absorption maximum is at 567 nm; the molar absorptivity is 2.9 × 10⁴lmole⁻¹cm⁻¹.     

The Young Julian Schwinger. II. Julian Schwinger at Columbia University

In this series of articles the life and work of the young Julian Schwinger are explored. In this second article in the series, Schwinger's work at Columbia University, up to the completion of his doctorate and a little after, is discussed. Schwinger soon matured into a brilliant theoretical physicist.     

Evaluation of 4-amino-2-hydroxybenzoic acid as an eluent for indirect photometric determination of uncommon anions

Summary The efficacity of 4-amino-2-hydroxybenzoic acids as an eluent for the separation and determination of uncommon anions has been evaluated. The intensely absorbing eluent (λ_max 320 nm) offers a convenient indirect photometric approach to quantitate the species of interest in ppm and sub-ppm range. In the singlecolumn ion chromatography mode at 2 mM/2 mL/min and pH=6.0, clean separations of common and uncommon anions can be realized.     

A study of the effective line width in lithium ferrites using magneto microwave Kerr effect

A new technique to determine the effective line width ΔH_eff using the dimensional resonance phenomenon observed in magneto-microwave Kerr-effect experiment is discussed. This effect depends on the Permeability tensor components and the damping parameter α. The components of permeability tensor μ have been calculated theoritically and the damping parameter α is determined from experimental data. The measurements have been made at 24 GHz on three samples of lithium ferrite and their effective line widths have been obtained both in the partially magnetised and the saturated states of magnetisation. It has been found that ΔH_eff for two states of magnetisation are different. Further, the value of ΔH_eff obtained are higher than expected at this frequency. This suggests the possibility of additional relaxation mechanisms at dimensional resonance.     

Charge in cosmological models

The balanced field equations due to Penney are used to find solutions for cosmological models in the presence of charge. Herein, it is found that the introduction of charge adds additional terms to the Einstein conservation equation and distribution expressions. The curvature parameter is affected and it is concluded that whereas matter affects it positively, the charge does so negatively. There then arises also the possibility of an evolution of local systems against the background of a global expansion.     

A Kerr effect study of microwave behaviour of partially magnetised ferrites

Magneto-microwave Kerr effect has been experimentally studied on three ferrite samples in the Polder-Smit loss region. Experimental data have been compared with the theoretical values which were calculated on the basis that the real part of the permeability tensor element μ′ is given by Green and Sandy's expressions (IEEE Trans. Microwave Theory Tech. MTT-22, 641 (1974)). This has a term given by Schlomann for μ′₀, the permeability for the demagnetised state. No agreement is found between theoretical and experimental values hence the above expression for ν′₀ has been substituted by another one given by Sandy (Raytheon Tech. Memor. T-815 (1969)) which involves the average demagnetisation factor N. It is found that there is a good agreement between the theory and the experiment provided N is assumed to depend linearly on the magnetisation of the sample.     

Magneto-microwave Kerr effect in high conductivity Mn-Zn ferrites

Magneto-microwave Kerr effect has been studied both theoretically and experimentally on two samples of high conductivity Mn-Zn ferrites for one of which ($\text{λ4πM}{}_{\mathrm{s}}\text{ω}$) was greater and for another less than unity. The experimental measurements have been made with the help of a microwave interferometer. The technique is useful for determination of effective FMR linewidth in samples of larger dimensions. It is found that Rado's theory is unable to interpret these results for any of the samples, while Green and Sandy's phenomenological theory is able to do so for the sample to which it is applicable, viz. the one with $\text{λ4πM}{}_{\mathrm{s}}\text{ω}\text{< 1}$.