Complexes of some rare earth metals with 1-amino-4-hydroxyanthraquinone

La, Ce(III), Pr, Nd and Sm(III) form very stable reddishviolet 1:1 complexes with 1-amino-4-hydroxyanthraquinone in methanol. The stability constants are very similar.     

Spherical elastic-plastic waves

Zusammenfassung Es wird die Fortpflanzung elastisch-plastischer Spannungswellen in einem unendlichen Medium betrachtet, welches einer idealen Spannungs-Verformungs-Kurve folgt, Trescas Fliesskriterium unterworfen ist und einen sphärischen Hohlraum enthält, wobei an der Fläche des Hohlraumes ein Stoss angenommen wird. Ein rechnerisches Verfahren, basiert auf endliche Differenzen, wird entwickelt and ein Beispiel gegeben.

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Notation radial stress - tangential stress - K yield stress - _rr non-dimensional radial stress ( /K) - non-dimensional tangential stress ( /K) - , Lame's constants - K _b Bulk constant (=(3+2)/3) - v Poisson's constant - Material density - C Elastic wave velocity (=((+2)/)^1/2) - C _p Plastic wave velocity (=(K _b /)^1/2) - distance from center of cavity - r ₀ cavity radius - v non-dimensional radial co-ordinate (= /r ₀) - time - t non-dimensional time (=C /r ₀) - radial displacement - u non-dimensional radial displacement (=/r ₀) - particle velocity - v non-dimensional particle velocity (= /C) - pressure - P(t) non-dimensional pressure (= /K)     

Preparation and characterization of some stereochemically rigid seven-coordinate η-cyclopentadienyltris(N,N-dialkyldithiocarbamato)hafnium(IV) complexes

Summary N,N-Dialkyldithiocarbametohafnium(IV) complexes of the type -CpHf(S₂CNR₂)₃, (R = Me or Et) have been prepared in nonaqueous media by reacting dichlorodicyclopentadienylhafnium(IV) with sodium salts of substituted dithiocarbamic acids. Conductance and i.r. studies show that these complexes are nonelectrolytes in which all of the dithiocarbamate ligands are bidentate. A coordination number of seven may be assigned to hafnium(IV) in these complexes, 'H n.m.r. spectra of the complexes in CDCI₃ at ambient temperature (30°) indicate that the metal centered rearrangement and the S₂C N bond rotation are both slow on the n.m.r. time scale. A capped octahedron configuration is suggested for these complexes.Author to whore all correspondence should be addressed.     

Synthesis and spectroscopic studies of complexes of zinc(II) with N2O2 donor groups

Complexes of zinc(II) with N,N'-disalicylidene-1,2-phenylenediamine (H2dsp), N,N'-disalicylidene-3,4-diaminotoluene (H2dst), 4-nitro-N,N'-disalicylidene-1,2-phenylenediamine (H2ndsp) and N,N'-disalicylidene ethylenediamine (H2salen) have been prepared and characterized by elemental analysis, electronic, IR, 1H NMR and thermal studies. TG studies show that all complexes decomposed in one step. Kinetic and thermodynamic parameters were computed from the thermal decomposition data. The activation energy of complexes lies 60-87 kJ mol(-1) range.     

Availability analysis of crank-case manufacturing in a two-wheeler automobile industry

The paper describes the availability of crank-case manufacturing system in an automobile industry. The units discussed here fail either directly from normal working state or indirectly through partial failure state. The machines are subjected to both preventive and corrective maintenance. Failure and repair times of the units are independent. The problem is formulated using probability consideration and supplementary variable technique. The system of equations governing the working of system consists of ordinary as well as partial differential equations. Lagrange method and Runge–Kutta method is used to solve partial differential equation and ordinary differential equation respectively. The study reveals that successful program of preventive and routine maintenance will reduce equipment failures, extend the life of the equipment, and increase the system availability to considerable margin.     

PHOTOACOUSTIC SPECTROSCOPIC STUDIES OF POLYCYCLIC AROMATIC HYDROCARBONS: NAPHTHALENE CATION

The photoacoustic (PA) spectrum of naphthalene cation in boric acid glass, in the region 250–400 nm is reported for the first tune and compared with its optical absorption spectrum. The energy levels for the ions are calculated using open shell Wasilewski method with limited configuration interaction and used to interpret the observed PA spectrum.