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1

Models of viscosity characteristics η=η(b) of ferro-oil with different concentration of magnetic particles in the presence of external magnetic field

Frycz M., Czaban A.

Journal of KONES

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2014

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Vol. 21, No. 4

119--126

EN

The purpose of this article is to determine, identify and describe the viscosity characteristics of the ferro-oil with different concentrations of magnetic particles in the presence of an external magnetic field interaction. These characteristics are defined in the context of magnetic induction changes. These rheological tests were performed on a Physica MCR 301 rheometer. It was used a measuring system ‘plate to plate’ type which was armed with magneto-rheological research system MRD 180/1T. The tests were performed for the selected temperature of the medium i.e. 90°C, the shear rate θ changes were carried from 0 to 1000 1/s. Changes of the magnetic field intensity value were ranged from 0 to 500 mT. The selected concentrations of magnetic particles in a ferro-oil were 1%, 2%, 4%, 6% and 8% and the tested ferro-oil was product of FerroTec of Unterensingen (Germany), which is a mixture of colloidal mineral motor oil Penzzoil’s LongLife Gold's SAE 15W-40 with Fe3O4 magnetic particles and the surfactant. Analyses of the results, identify and matching characteristic were calculated using STATISTICA software. It has been proposed three categories of functions mapping the waveforms of the results obtained experimentally: the exponential function, logarithmic with basis of the normal and the polynomial function.

2

Effect of the magnetic particles concentration on the ferro-oil’s dynamic viscosity in presence of an external magnetic field in the aspect of temperature changes

Czaban A., Frycz M., Horak W.

Journal of KONES

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2013

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Vol. 20, No. 2

55--60

EN

There is presented an effect of the changes of the concentration of magnetic particles included in the ferro-oil on its dynamic viscosity in the presence of external magnetic field in this paper. The study was conducted in the context of temperature’s changes. The authors assume that the concentration of magnetic particles in ferro-oil can significantly affects its basic physical properties as dynamic viscosity, as well as the operational properties of journal sliding bearings ferro-oil’s lubricated. The equally significant as the above mentioned properties may affect the external environmental conditions of operation, especially temperature changes. In this context, an important technique’s issue appears to determine the principles of selection of optimal concentration of above mentioned particles according to the existing environmental conditions of its operation, or the expectations laid against the operation of the devices. Rheological studies were carried out on Physica MCR 301 rheometer in the “plate-to-plate” measurement system with an adapter to magneto-rheological studies MRD 180/1T. Thermal stabilization was carried out by a water jacket in a closed chamber and controlling the nature of the magnetic field was conducted by current’s changes. Tests were performed for four selected temperature range of 60º, 70º, 80º and 90ºC as regards changes an external magnetic field intensity 0-700 mT. The selected concentrations of magnetic particles in a ferro-oil were 1, 2, 4, 6 and 8%.

3

Influence of the external magnetic field on operation of the electromagnetic current-to-voltage transducer

Leśniewska E., Jałmużny W.

Przegląd Elektrotechniczny

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2008

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R. 84, nr 11

57-59

EN

The analysis of the influence of the external magnetic field on the ratio error of current-to-voltage transducers is presented in this paper. Application of 2D field-and-circuit method to investigate elimination of the influence of the external field enabled the selection optimal shielding. Variations of shield design electromagnetic and magnetic shields as well as different materials and shapes of these shields were considered. Computational results were compared with test results.

PL

W artykule przedstawiono analizę wpływu zewnętrznych pól magnetycznych na błąd przetwarzania transreaktorowych przekładników prądowych. Zastosowanie dwuwymiarowej metody polowo obwodowej do rozpatrzenia zagadnienia eliminacji wpływu pól zewnętrznych pozwoliło na określenie najlepszego sposobu ekranowania. Rozpatrzono różne warianty ekranów magnetycznych i elektromagnetycznych. Porównano również otrzymane metodą polowo-obwodową wyniki z wynikami badań na modelach fizycznych.

4

Failure criteria for electromagnetic materials

Chudzicka-Adamczak M.

Vibrations in Physical Systems

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2006

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Vol. 22

101--106

5

The vortex dynamics in HTc superconductor in external magnetic field

Sosnowski J.

Journal of Technical Physics

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2005

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Vol. 46, no 4

245-255

EN

The penetration of magnetic induction into HTc superconductors has been considered taking into account the layered structure of these materials. For magnetic field parallel to the planes a one-dimensional penetration has been considered, while in perpendicular magnetic field it is a two-dimensional problem. The flux creep equation has been considered, whose solution was confirmed by experimental data measured on an Y-Ba-Cu-O sample. The magnetic diffusion equation has been solved for a description of the magnetic induction profiles in an increasing external magnetic field. The dynamic anomalies of the current-voltage characteristics have been then predicted, in agreement with experimental observations. The model taking into account the influence of the vortex-pinning center interaction on the magnetic field dependence of the critical current, has been also applied successfully for description of the anomalies.

6

Studies of ion fluxes emitted from picosecond and nanosecond laser-produced plasmas

Badziak J., Parys P., Wołowski J., Woryna E.

Journal of Technical Physics

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2004

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Vol. 45, no 1

3-20

EN

Energetic ions emitted from plasmas produced by the interaction of intense laser pulses with solid targets are currently a subject of growing interest due to the possibility of unique applications in accelerator technology, nuclear physics, material science and medicine. Depending on the kind of application, different parameters of the ion fluxes are required, and various conditions of laser-target interaction must be considered. In this paper, selected results of our recent studies of ion emission from plasmas produced by laser pulses of duration from ~ 1 ps to ~ 1 ns and of intensities from 10^10 W/cm^2 to 10^17 W/cm^2 are reviewed. The characteristics of both heavy ion fluxes emitted from massive high-Z targets and proton beams generated from thin foil targets of various structures are presented. Some basic properties of ion fluxes produced in various experimental conditions are discussed. The effect of external magnetic field on the ion emission is demonstrated.

7

Non-Newtonian flows over an oscillating plate with variable suction

Hayat T., Abbas Q., Khan M., Siddiqui A. M.

Archives of Mechanics

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2003

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Vol. 55, nr 4

327-344

EN

The flow of second order fluid due to an oscillating infinite plate in the presence of a transverse magnetic field for two forms of time-depend suction are considered. The analytical solution of the governing boundary value problems are obtained. It is found that an external magnetic field and normal stress coefficient on the flow has opposite effects.