Finite element analysis of high field permanent magnet mechanism using vector Preisach hysteresis model
This paper presents a method to simulate abnormal magnetizations in high field permanent magnet mechanism. Abnormal magnetizations including local saturation, local demagnetization and rotational magnetization occur in the assembly process of high field permanent magnet mechanism. Combining an anisotropic vector Preisach model and finite element analysis, abnormal magnetizations are simulated comprehensively. The method only requires the data of limiting magnetic hysteresis loops of the material along easy and hard axis, so the application of vector Preisach model becomes convenient and efficient. A sixteen elements enhanced magic ring is designed and the process of assembling is simulated, which verify the validity of the presented method.
Computation of magnetic field in memdia with hysteresis
The vector Preisach hysteresis model is employed for the calculation of static magnetic fields in media with hysteresis. A time-stepping technique is used to trace a history of the magnetizing process. At each time step, a magnetization integral equation is employed, and a special technique for the solution of this equation is discussed. Theoretical considerations are illustrated by a numerical example. The attractive features of the model considered are its computational efficiency, ability to describe nonsymmetrical minor hysteresis loops, and the existence of well-developed identification procedures. >
Rational Design, Synthesis and Evaluation of γ-CD-Containing Cross-Linked Polyvinyl Alcohol Hydrogel as a Prednisone Delivery Platform
This study describes the in-silico rational design, synthesis and evaluation of cross-linked polyvinyl alcohol hydrogels containing γ-cyclodextrin (γ-CDHSAs) as platforms for the sustained release of prednisone (PDN). Through in-silico studies using semi-empirical quantum mechanical calculations, the effectiveness of 20 dicarboxylic acids to generate a specific cross-linked hydrogel capable of supporting different amounts of γ-cyclodextrin (γ-CD) was evaluated. According to the interaction energies calculated with the in-silico studies, the hydrogel made from PVA cross-linked with succinic acids (SA) was shown to be the best candidate for containing γ-CD. Later, molecular dynamics simulation studies were performed in order to evaluate the intermolecular interactions between PDN and three cross-linked hydrogel formulations with different proportions of γ-CD (2.44%, 4.76% and 9.1%). These three cross-linked hydrogels were synthesized and characterized. The loading and the subsequent release of PDN from the hydrogels were investigated. The in-silico and experimental results showed that the interaction between PDN and γ-CDHSA was mainly produced with the γ-CDs linked to the hydrogels. Thus, the unique structures and properties of γ-CDHSA demonstrated an interesting multiphasic profile that could be utilized as a promising drug carrier for controlled, sustained and localized release of PDN.