A method for estimating the local lattice distortions near a magnetic ion from ligand hyperfine parameters: Yb3+trigonal centers in SrF2 and BaF2

An empirical relationship describing the radial dependence of the nondipole part of the anisotropic constant for the ligand hyperfine interaction in alkaline-earth fluorides is proposed. This relationship is used for calculating the distances between the magnetic ion and the fluorine ions involved in its nearest environment. The results of the calculations are in good agreement with the values obtained by other methods for both cubic and tetragonal fluorine centers in these crystals. The distances from the magnetic ion to different groups of nonequivalent fluorine ions of the nearest environment in Yb³⁺ trigonal centers of SrF₂ and BaF₂ are determined. It is found that the Yb³⁺ ion is slightly displaced along the trigonal axis away from the compensating fluorine ion.     

Surface morphology of electrolytic deposits of vanadium, cobalt, and manganese oxides

The surface morphology of V₂O₅, Co₂O₃, and MnO₂ electroplated under different electrolysis conditions was studied. The nature of the electrocrystallization of these materials was suggested on the basis of the analysis results.     

Practical aspects associated with location planning for maternal and perinatal assistance in Brazil

A study has been carried out aimed at reducing perinatal mortality in the municipality of Rio de Janeiro through a better distribution of health care facilities. The algorithmic aspects are detailed elsewhere and here the emphasis is on practical issues and difficulties encountered. A 3-level hierarchical model was developed. Both uncapacitated and capacitated versions are briefly described together with some results based on actual data. The project brought to light many contradictions between OR theory and practice in developing countries and, unfortunately, the models developed were not implemented by the municipality health authorities. Possible reasons for this outcome are analysed.     

Journey Making group workshops as a research tool

Problem-structuring group workshops can be used in organizations as a consulting tool and as a research tool. One example of the latter is using a problem-structuring method (PSM) to help a group tackle an organizational issue; meanwhile, researchers collect the participants’ initial views, discussion of divergent views, the negotiated agreement, and the reasoning for outcomes emerging. Technology can help by supporting participants in freely sharing their opinions and by logging data for post-workshop analyses. For example, computers let participants share views anonymously and without being influenced by others (as well as logging those views), and video-cameras can record discussions and intra-group dynamics. This paper evaluates whether technology-supported Journey Making workshops can be effective research tools that can capture quality research data when compared against theoretical performance benchmarks and other qualitative research tools.     

Direct mass measurements of neutron-deficient 152Sm projectile fragments at the FRS-ESR facility

The FRS-ESR facility at GSI provides one of the most efficient methods for direct mass measurements. In the present experiment, exotic nuclei were produced via fragmentation of ¹⁵²Sm projectiles in a thick beryllium target at 500-600 MeV/u, separated in-flight with the fragment separator FRS, and injected into the storage-cooler ring ESR. Time-resolved Schottky Mass Spectrometry was applied for mass measurements of stored and electron-cooled bare and few-electron ions. 373 different nuclides were identified by means of the spectra of their revolution frequencies. Masses for 18 nuclides (⁸⁴Zr, ⁹²Ru, ⁹⁴Rh, ^107,108,110Sb, ^111,112,114I, ¹¹⁸Ba, ^122,123La, ¹²⁴Ce, ¹²⁷Pr, ¹²⁹Nd, ¹³²Pm, ¹³⁴Sm, ¹³⁷Eu) have been determined for the first time. Masses for ^111,112I and ¹¹³Xe have been obtained via known α-decay energies. The experiment and first results will be presented.     

Mössbauer studies of the re-entrant spin-glass behaviour of Fe–Al alloys

Fe–Al alloys around the concentration of 30 at. % Al present re-entrant spin-glass behaviour at low temperatures. This behaviour is not completely understood and Mössbauer spectroscopy, combined with other experimental techniques, is useful to describe and explain this behaviour. Results show that the Mössbauer spectra coincide with the magnetic behaviour showed in literature and they can be explained as a magnetic cluster system whose magnetic clusters are getting smaller when the temperature is decreasing. When the temperature is reaching to the spin-glass transition at 92 K the spins in the paramagnetic matrix are moving slower and below this transition the spins are completely frozen.     

Solid solubility of the oxisulfides of Y, La, and Gd

The solid solubility in the systems Y₂O₂S---La₂O₂S, Y₂O₂S---Gd₂O₂S, and Gd₂O₂S---La₂O₂S has been investigated. Solid solutions of all compounds, throughout the whole composition range, were readily obtained, using coprecipitated oxalates and a polysulfide flux.     

Bending-torsion vibration of a partially submerged cylinder with an arbitrary cross-section

An analytical method is presented to investigate the bending-torsion vibration characteristics of a cylinder with an arbitrary cross-section and partially submerged in water. The compressibility and the free surface waves of the water are considered simultaneously in the analysis. The exact solution of structure–water interaction is obtained mathematically. Firstly, the analytical expression of the velocity potential of the water is derived by using the method of separation of variables. The unknown coefficients in the velocity potential are determined by the longitudinal and circumferential Fourier expansions along the outer surface of the cylinder and are expressed in the form of integral equations including the unknown dynamic bending deflection and torsional angle of the cylinder. Secondly, the force and torque acting on the cylinder per unit length, provided by the water, are obtained by integrating the water dynamic pressure along the circumference of the cylinder. The general solution of bending-torsion vibration of the cylinder under the water dynamic pressure is derived analytically. The integral equations included in the velocity potential of the water can be solved exactly. Finally, the eigenfrequency equation of cylinder–water interaction is obtained by means of the boundary conditions of the cylinder. Some numerical examples for elliptical columns partially submerged in water are provided to show the application of the present method.