Frequency- and Temperature-Dependent Uncertainties in Hysteresis Measurements of a 3D-Printed FeSi wt6.5% Material.

Additive manufacturing of soft magnetic materials is a promising technology for creating topologically optimized electrical machines. High-performance electrical machines can be made from high-silicon-content FeSi alloys. Fe-6.5wt%Si material has exceptional magnetic properties; however, manufacturing this steel with the classical cold rolling methodology is not possible due to the brittleness of this material. Laser powder bed fusion technology (L-PBF) offers a solution to this problem. Finding the optimal printing parameters is a challenging task. Nevertheless, it is crucial to resolve the brittleness of the created materials so they can be used in commercial applications. The temperature dependence of magnetic hysteresis properties of Fe-6.5wt%Si materials is presented in this paper. The magnetic hysteresis properties were examined from 20 °C to 120 °C. The hysteresis measurements were made by a precision current generator-based hysteresis measurement tool, which uses fast Fourier transformation-based filtering techniques to increase the accuracy of the measurements. The details of the applied scalar hysteresis sensor and the measurement uncertainties were discussed first in the paper; then, three characteristic points of the static hysteresis curve of the ten L-PBF-manufactured identical toroidal cores were investigated and compared at different temperatures. These measurements show that, despite the volumetric ratio of the porosities being below 0.5%, the mean crack length in the samples is not significant for the examined samples. These small defects can cause a significant 5% decrement in some characteristic values of the examined hysteresis curve.

[Difficulties encountered during formulation of a parenteral dosage form containing a poorly soluble drug]. / Rossz vízoldékonyságú hatóanyagok parenterális gyógyszerformaként történo formulálásánál felmerülo problémák.

Poor water solubility and consequently the difficulties in formulating a liquid dosage form is a great concern in pharmaceutical development. The importance of this issue is underlined by the fact that 10-30% of marketed drugs and 60-70% of drugs coming from early development stage have solubility problems. In this paper we summarize the existing solubility enhancing techniques that are applicable in parenteral dosage forms for overcoming the issue. We address the problem of choosing the most adequate solubility enhancing technique and present the considerations that should be kept in mind during formulating the solvent systems. Such questions are for example the possible haemolysing effect of the excipients, pH of the composition and its compatibility with various sterilizing methods. We also focus on the probable technological issues, which may arise in each solubility enhancing method, we present examples for every one of them and where possible the solution to the problem is also proposed.