Materials Science Forum Vol. 721

Abstract: We introduce a metamaterial based parallel-plate waveguide, devised in microstrip technology that features two electromagnetic band-gaps. Since one of the band-gaps extends from zero frequency, the structure can be used as a band-pass filter. We perform a parametric study in view of facilitating design and optimisation.

Abstract: An eddy current method was applied to evaluate amount of sigma phase in duplex stainless steel. In the preliminary experiments several transducers configuration were considered. The performance of the transducers were verified utilizing samples having different amount of sigma phase. The configurations presenting the greatest possibility of evaluation of sigma phase were chosen for further experiments. In this paper a dedicated transducer operating in differential mode will be presented. The results will be shown and discussed.

Abstract: Quantum effects in nanostructured magnetic solid state materials open the new ways for preparing the novel electromagnetic devices with unique characteristics. At the same the electron spin based quantum effects are fully determined of formation and growing properties of molecular clusters of these solid state materials which are united in plane and volume structures also according their quantum (elementary particle interactions) properties.

Abstract: The implementation of magnetostrictive delay lines in distribution measurement of temperature is presented in this paper. The sensing method and measurements as well as the proper selection and treatment of the amorphous sensing core are discussed.

Abstract: At high AC field strength, BH loop tends to twist slightly near the tip point. It results in apparent decrease of iron loss because the overturned parts introduce negative iron loss value. In order to correct this error the phase difference between flux density and magnetic field strength needs to be eliminated. We studied on the problem and got satisfactory results.

Abstract: To obtain the basic data to manufacture the highly effective rotating machine, the axial iron loss distribution of an actual stator core of the complex structure was evaluated by using the small excitation inner core. The laminated thickness of this small excitation inner core is approximately 1/6 of the thickness of the stator core. Therefore, the circumferential iron loss distribution of the stator core and the axial iron loss distribution of a stator core can be measured by using this small excitation inner core. Then, to compare the difference of the axial iron loss distribution in the stator core, we investigated the axial iron loss distribution in the actual stator core after two manufacturing processes, the laminating process and the shrink fitting process. The iron losses were measured in three places (the edge, the quarter part, and the center) of two stator cores. As a result of our investigation, the axial iron loss distribution in the actual stator core clearly changed. This paper reports on the axial iron loss distribution in two manufacturing processes in two actual stator cores measured by using the small excitation inner core.

Abstract: In the present work the microstructure and the strain induced phase transformation of a Lean Duplex Stainless Steel (LDSS) were studied. Sheet samples were cold rolled, the number of samples was nine; the applied deformation was up to 80%. The magnetization curves were measured by a single sheet tester-type magnetic property analyzer. The series of symmetrical minor hysteresis loops and the saturation loop were measured. Our novel data evaluation technique was applied for data evaluation of the magnetic measurements. This method is based on the multiphase-hyperbolic model of magnetization and it is called model based data evaluation (MBDE) technique. This method allowed us to separate the magnetic contribution of ferrite and martensite phases in the tested LDSS. Several new details of the kinetics of austenite→martensite strain induced phase transformation were clarified.

Abstract: Experimental studies of the behavior of magnetic fluid drop under the effect of an external alternating magnetic field were performed using a high speed digital video camera system. A small permanent magnet was immersed in magnetic fluid drop, and it was fixed with an aluminum bar. The surface of magnetic fluid responded to the external magnetic field sensitively. The free surface of the magnetic fluid drop responded to the external alternating field in elongation and contraction along the direction of the field. The capillary magnetic fluid jet was produced at the certain external magnetic field condition.

Abstract: The dynamic behavior of a magnetic fluid droplet adsorbed to magnetized needlepoint in alternating magnetic field was studied with a high speed video camera system. The directions of alternating magnetic field were parallel and opposite to static magnetic field of magnetized needlepoint. It was found that the surface of magnetic fluid droplet responds to the external magnetic field in elongation and contraction. The frequency of magnetic fluid droplet oscillation was exactly same of the external magnetic field. The shape and instability oscillations of the magnetic fluid droplet were revealed experimentally.

Abstract: MR (Magnetic Rheological) fluid is a kind of functional fluid, which can be hardened by impressing magnetic flux. MR fluid has the high speed response to the external magnetic field and a big yield stress in comparison with the ferrofluid. In recent years, various devices utilizing MR fluid have been developed. Such developments are enabled with knowledge based on measured viscoelastic properties of MR fluid. However, precise measurement to obtain effect of the magnetic field on viscoelasticity is very difficult. The difficulty exists in generating a uniform magnetic field and evaluating the effective magnetic field. Accurate measurements become possible by solving these problems. In this paper, we propose a new magneto-viscoelasticity measurement system of MR fluid, which can generate a uniform magnetic field.