Behavior of a free surface of a magnetic fluid containing a magnetizable cylinder

The deformation of the free surface of a magnetic fluid containing a cylinder made of a magnetizable material subjected to a uniform applied magnetic field is analyzed. The statics and dynamics of a magnetic fluid free surface is studied theoretically and experimentally. A discontinuous (jump-like) change of the surface shape is shown to occur when the applied magnetic field gradually increases or decreases. If the applied magnetic field increases and then decreases, a hysteresis of the shape is observed.     

Two-layer flow of magnetic fluids

The plane two-layer flow of viscous incompressible fluids with differentmagnetic properties between two horizontal rigid planes in a nonuniform traveling magnetic field is investigated. An arbitrary nonuniform periodic traveling magnetic field generates wavelike changes in the interface between the media and fluid flows with nonzero flow rates. From the given magnetic field the interface shape and the velocities, pressures and mean flow rates of the fluids are calculated. The cases of a cosine magnetic force and of the magnetic field created by ferromagnetic cylinders moving in a uniform magnetic field are considered. The effect of various parameters on the mean flow rates of the fluids is investigated.     

Shape of the free surface of a magnetic fluid containing a cylindrical concentrator of the magnetic field

The shape of the surface of a magnetic fluid containing a cylindrical body made of a well-magnetizable material (magnetic field concentrator) in a uniform applied magnetic field is studied experimentally and theoretically. Various static shapes of the surface are calculated numerically taking into account the gravity forces, the surface tension, and the dependence of the magnetic fluid magnetization on the magnetic field strength. It is found that there exists several equilibrium shapes of the magnetic fluid surface. Abrupt changes in the magnetic fluid surface and its hysteresis are predicted theoretically and observed experimentally. The theoretical and experimental results are compared.     

Statics of a magnetic fluid containing magnetic field concentrators

Various static surface shapes of a magnetic fluid containing bodies made of easily magnetizable materials (magnetic field concentrators) in a uniform applied magnetic field are numerically calculated with account for the gravity force, surface tension, and the dependence of the magnetic-fluid magnetization on the magnetic field strength. The possibility of a sudden change in surface shape is shown. Hysteresis in the surface shape with a cyclic increase and decrease in the applied field is predicted.     

Micellization kinetics with allowance for fussion and fission of spherical and cylindrical micelles: 1. Set of nonlinear equations describing slow relaxation

Based on the general kinetic equation that describes the aggregation and fragmentation of surfactant molecular aggregates, a closed set of nonlinear equations is derived for the slow relaxation of surfactant monomer concentration and the total concentrations of coexisting spherical and cylindrical micelles to the equilibrium state of a micellar solution. Both the transitions accompanied by the emission and capture of surfactant monomers by micelles and the transitions resulting from the fussion and fission of micelles, are taken into account. The derived set of equations describes all stages of the slow relaxation from the initial perturbance to the final equilibrium state of a micellar solution.     

Mass spectrometric study of the vaporization of N,N′-<Emphasis Type="Italic">o</Emphasis>-phenylene-bis(salicylideniminate) nickel(II), copper(II), and zinc(II) and N,N′-ethylene-bis(salicylaldiminate) zinc(II) complexes

The thermodynamics of vaporization of Ni(saloph), Cu(saloph), Zn(saloph), and Zn(salen) complexes are studied by Knudsen effusion method with mass spectrometric control of the vapor composition. It is noted that in the mass spectra of Zn(saloph) and Zn(salen), there are low-intensity peaks corresponding to ions of dimer. The effect of the nature of a metal and a ligand on the behavior of fragmentation of the complexes during their ionization with electrons is discussed. The enthalpies of sublimation, ΔH _s ^○ (T), are calculated by second law of thermodynamics: Ni(saloph) (502–578 K), 163 ± 1 kJ/mol; Cu(saloph) (475–550 K), 162 ± 1 kJ/mol; Zn(saloph) (571–637 K), 176 ± 4 kJ/mol; Zn(salen) (568–634 K), 169 ± 2 kJ/mol.     

Molecular structure of N,N′-o-phenylene-bis(salicylideneaminato)copper(II) studied by gas-phase electron diffraction and quantum-chemical calculations

The molecular structure of N,N′-o-phenylene-bis(salicylideneaminato)copper(II) (Cu(saloph)) was determined using the combination of gas-phase electron diffraction (GED), mass spectrometry, and quantum-chemical calculations. According to both experimental and theoretical approaches the molecule of Cu(saloph) is planar and possesses C _2v symmetry. Main structural parameters determined by GED experiment are the following (total error is given in a brackets): r _h1(Cu–N) = 1.960(20) Å, r _h1(Cu–O) = 1.913(17) Å, ∠NCuN = 82.7(18)°, ∠OCuO = 91.6(21)°, ∠NCuO = 92.9(9)°. The experimental structural parameters of Cu(saloph) molecules determined by X-ray single crystal analysis and GED experiments were discussed and compared to the theoretical ones.

     

Structure of a zinc(II) N,N’-ethylene-bis (acetylacetoniminate) molecule,ZnO<Subscript>2</Subscript>N<Subscript>2</Subscript>C<Subscript>12</Subscript>H<Subscript>18</Subscript>, according to gas electron diffraction data and quantum chemical calculations

Gas electron diffraction is used to study the structure of a zinc(II) N,N’-ethylene-bis(acetylacetoniminate) molecule, ZnO₂N₂C₁₂H₁₈, at a temperature T = 503(5) K. It is found that the molecule has the symmetry of the C₂ equilibrium configuration with a nonplanar structure of the ZnN₂O₂ coordination fragment and internuclear distances r_h1(Zn-O) of 1.958(13) ? and _h1(Zn-N) of 2.012(16) ?. Quantum chemical calculations by the DFT/B3LYP/CEP,TZV method gives the molecular structure consistent with that found in the experiment.