A Comparative Study of Finite Element Method and Hybrid Finite Element Method–Spectral Element Method Approaches Applied to Medium-Frequency Transformers with Foil Windings

This study aims to improve the computational efficiency of the frequency domain analysis of medium-frequency transformers (MFTs) with the presence of large clearance distances and fine foil windings. The winding loss and magnetic energy in MFTs in the medium-frequency range are calculated utilizing a finite element method (FEM) using common triangular and alternative rectilinear mesh elements. Additionally, in order to improve the computational efficiency of the calculations, a spectral element method (SEM) is coupled with a FEM, thus creating a hybrid FEM–SEM formulation. In such a hybrid approach, the FEM is used to calculate the current density distribution in the two-dimensional (2D) cross-section of the foil conductors to achieve reliable accuracy, and the SEM is adopted in the nonconducting clearance distances of the winding window to reduce the system of equations. The comparative analysis of the calculated resistance and reactance of the under-study models showed that the FEM with rectilinear mesh elements and the FEM–SEM model outperformed the FEM with triangular mesh elements in terms of accuracy and computational cost. The hybrid FEM–SEM model enables a reduced system of equations for modeling the electromagnetic behavior of MFTs. This research provides valuable insights into both the computational approaches and meshing challenges in the analysis of MFTs and offers a foundation for future research on the design and optimization of MFT

Student-stage bij het Kabinet van de Commissaris der Koningin: Stageverslag

Gegrepen door de monarchie als staatsvorm heb ik ervaring willen opdoen bij een bestuurseenheid die in haar werkzaamheden intensief met Koninklijk Huis coöpereert. Omdat het Kabinet van de Commissaris van de Koningin, naar mijn mening, een dergelijk eenheid is, heb ik, toen ik tijdens het mede door mij georganiseerde Landelijk Congres der Bestuurskunde de Commissaris der Koningin, mijnheer Franssen, ontmoette, bij hem geïnformeerd naar stagemogelijkheden. Dit heeft er toe geleid, dat ik van 17 september 2001 tot 17 januari 2002 een stageplaats bij zijn Kabinet kreeg aangeboden

A convenient diagnostic function test of peripheral blood neutrophils in glycogen storage disease type Ib

Neutrophils from patients suffering from glycogen storage disease type To (GSD-Ib) show several defects, one of which is a decreased rate of glucose utilization. In this study, we established experimental conditions to show the stimulation of the neutrophil respiratory burst by extracellular glucose. With phorbol-myristate-acetate as stimulus of the burst, the activity of the NADPH oxidase in GSD-Ib neutrophils hardly increased on addition of glucose. Tn control and GSD-type Ia neutrophils, a clear increase was observed, The lack of response to extracellular glucose in GSD-lb neutrophils is correlated with the inability to raise intracellular glucose-6-P levels on glucose addition, thereby limiting the activity of the generation of NADPH in the hexose-monophosphate shunt. Our study shows the usefulness of this test for the diagnosis of neutrophil function abnormality in GSD-To patients

A convenient diagnostic function test of peripheral blood neutrophils in glycogen storage disease type Ib

Neutrophils from patients suffering from glycogen storage disease type To (GSD-Ib) show several defects, one of which is a decreased rate of glucose utilization. In this study, we established experimental conditions to show the stimulation of the neutrophil respiratory burst by extracellular glucose. With phorbol-myristate-acetate as stimulus of the burst, the activity of the NADPH oxidase in GSD-Ib neutrophils hardly increased on addition of glucose. Tn control and GSD-type Ia neutrophils, a clear increase was observed, The lack of response to extracellular glucose in GSD-lb neutrophils is correlated with the inability to raise intracellular glucose-6-P levels on glucose addition, thereby limiting the activity of the generation of NADPH in the hexose-monophosphate shunt. Our study shows the usefulness of this test for the diagnosis of neutrophil function abnormality in GSD-To patients