Preparation, characterization, and X-ray structure analysis of diethylenetriammonium tetrathiomolybdate

The interaction of H₂S gas with aqueous ammonium heptamolybdate solution in the presence of diethylenetriamine (dien) led to the formation of diethylenetriammonium tetrathiomolybdate crystals. The elemental analyses, UV-Visible, IR, and ¹H NMR spectra suggested the presence of organic cation and (MoS₄)^2– moiety. The ¹H NMR revealed the presence of two sets of symmetrical A₂X₂ multiple patterns. The compound crystallizes in the monoclinic system with space group Pn, a = 7.196(6), b = 7.532(3), c = 11.525(10) Å, = 90°, = 90.17(3)°, = 90°, V = 624.78(8) ų, and Z = 2, wR ₁ = 0.0261 and wR ₂ = 0.0698. The structure consists of tetrahedral tetrathiomolybdate anions, which form an extended three-dimensional network in the solid state with Mo–SH–N hydrogen bonding with the organic cation.     

Guest Editorial

Journal of Sol-Gel Science and Technology -     

Low temperature 151Eu and 57Fe Mössbauer study of mechanically alloyed EuFeO3

Low temperature ⁵⁷Fe Mössbauer spectra of mechanically alloyed EuFeO₃ prepared by mechanical alloying depicts an interesting transformation in its hyperfine magnetic state, from a triple phase magnetic system at room temperature to a single phase ferromagnetic state at 20 K. The hyperfine magnetic field increased by 12% at 20 K from its room temperature. The isomer shift and quadrupole splitting values exhibit a peak around 200 K. Low temperature ¹⁵¹Eu Mössbauer measurements show that the line-width increased to its maximum value at 80 K which is 45% compared to its room temperature value not enough to suggest splitting.     

Evaluation of thermo-oxidative characteristics of gear oils by different techniques: Effect of antioxidant chemistry

This paper deals with determination of the oxidation stability of gear oils formulated with antioxidants of different chemistries. The oxidation stability has been studied by PDSC, TGA, micro-oxidation, RPVOT and IP 48. The effect of different antioxidants on the thermo-oxidative properties of gear oil is evaluated.     

Preparation of nitropyridines by nitration of pyridines with nitric acid

Nitration of pyridines 1a-o with nitric acid in trifluoroacetic anhydride, gave the corresponding 3-nitropyridines 6a-n in yields of 10-83%.     

Experimental results on proton diffractive dissociation

Properties of proton diffractive dissociation have been investigated for four-prong final states in proton-proton reactions at 360 GeV/c, in particular forpp→ppπ ⁺π^? mπ ⁰(m=0,1,2). Mass distributions and decay angular distributions are given. The decay of the diffractive system is seen to be very anisotropic, and largep _T is suppressed at higher masses. It is found that the “pomeron” couples with a single valence quark of the incident proton, but indications for a diquark-pomeron coupling are also found. Similarities with fragmentation in lepton-hadron deep inelastic scattering are underlined.     

Decomposition mechanism of copper ammonium chromate: A basic material for copper chromite catalyst

The mechanism of thermal decomposition of basic copper ammonium chromate has been investigated using TG/DTG/DSC and X-ray studies. The decomposition is a three-step process. Calcination at lower temperatures can be achieved by taking advantage of the exothermicity of the decomposition process.     

A study of np annihilations around 0.65 GeV/c

$\text{n}\text{p}$ annihilations with ? 3 prongs with an incident antineutron momentum between 0.5 and 0.8 GeV/c are analysed. We present the topological branching ratios and cross sections, the resonance production rates and possible ?-ω interference effects.     

Axisymmetric shrink fit problems of the elastic cylinder of finite length

The general case of the axisymmetric shrink fit problems of a solid elastic cylinder whose ends are free from tractions is formulated in terms of the Fredholm integral equation of the second kind. This is accomplished by the use of Papkovich-Fadle eigenfunction and the calculus of residues. Indentation by three types of sleeve is considered; (i) Edge Sleeve, (ii) Symmetrical central Sleeve and, (iii) Two identical edge sleeves. For each case, numerical results of effective resistance and contact pressure are reported for various values of the Poisson's ratio, radius of the cylinder and the sleeve width.

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Zusammenfassung Der allgemeingültige Fall achsensymmetrischer Schrumpf-Anpassungs probleme eines elastischen Festzylinders dessen Enden zugkraftfrei sind wird in der Form der zweiten Integral-gleichung von Fredholm ausgedrückt. Dies wird durch die Anwendung der Papkovich-Fadle Eigenfunktion und der Residuenrechung erreicht. Drei Arten von Manteleinkerbungen werden untersucht: (i) einseitige Endeinkerbung, (ii) symmetrische Zentraleinkerbung, (iii) zweiseitige Endeinkerbung. Für jeden Testfall werden die Zahlenergbnisse des effektiven Winderstandes und des Berührungsdruckes für verschieden Werter der Poisson Ratio, des Zylinderradius und der Mantelkerbweite berichtet.

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The present results were obtained in the course of research supported by NSF Grand GK-25604.     

A study of inclusive Ξ− production from K−p interactions at 4.2 GeV/c

A study of inclusive Ξ^? production from a high statistics K^?p experiment at 4.2 GeV/c has been made. The total Ξ^? production cross section is 157 ± 8 μb. Approximately 15% of the Ξ^? arise from decay of the Ξ¹⁰(1530) resonance. The polarization of the Ξ^? is found to be negative and is nearly equal in value to that of the Λ⁰ from the inclusive reaction K^? + p → Λ⁰ + anything. An analysis of the inclusive production of Ξ^? has been made in the framework of the triple-Reege formalism.