A Low-loss and Lightweight Magnetic Material for Electrical Machinery.

A low-loss and lightweight core material, with applications in electrical machinery, is made of highly packed and insulated magnetic microwires (MWs). These MWs are aligned in such a way as to guide the flux in the rotor/stator, with the ultimate goal of increasing efficiency and substantially reducing core losses. Commercial FebalNi29Co17-based MWs with a 127 µm diameter and a 33 µm insulation coating are utilized. The magnetic measurements of the fabricated sample demonstrate high permeability and low core loss in a wide range of frequencies. To prove the utility of this type of material, we used it in the rotor core of a prototype 25 Watt three-phase synchronous reluctance machine (SyncRM). The core is lighter, and the losses are significantly lower than in conventional core materials under the same torque density.

Finite Difference Micromagnetic Solvers with the Object Oriented MicroMagnetic Framework (OOMMF) on Graphics Processing Units.

A micromagnetic solver using the Finite Difference method on a Graphics Processing Unit (GPU) and its integration with the Object Oriented MicroMagnetic Framework (OOMMF) are presented. Two approaches for computing the magnetostatic field accelerated by the Fast Fourier Transform (FFT) are implemented. The first approach, referred to as the tensor approach, is based on the tensor spatial convolution to directly compute the magnetostatic field from magnetic moments. The second approach, referred to as the scalar potential approach, uses differential operator evaluation through finite differences (divergence for magnetic charge and gradient for magnetostatic field) and spatial convolution for magnetic scalar potential. Comparisons of implementation details, speed, memory consumption and accuracy are provided. The GPU implementation of OOMMF shows up to 32x GPU-CPU speed-up.

Quinacrine for extremity melanoma in a mouse model of isolated limb perfusion (ILP).

PURPOSE: Quinacrine is a relatively non-toxic drug, once given almost exclusively for malaria. However, recent studies show that quinacrine can suppress nuclear factor-κB (NF-κB), and activate p53 signaling. We investigated the anti-cancer effect of quinacrine, using a novel mouse model of isolated limb perfusion (ILP) for extremity melanoma. METHOD: Female C57BL/6 mice (22-25 g) were injected with B16 melanoma cells (1 × 10(5)) subcutaneously in the distal thigh. After 7 days of tumor establishment, mice were perfused with either PBS, melphalan (90 µg), or quinacrine (3.5 and 4.5 mg) through the superficial femoral artery for 30 min at either 37 or 42 °C in a non-oxygenated circuit. We analyzed morbidity, toxicity, tumor apoptosis, and responses. RESULTS: Melanoma cell death following in vitro exposure to quinacrine was dose and time dependent. A significant decrease in mean tumor volume was observed after perfusion with low-dose and high-dose quinacrine (both P = 0.002) at 37 °C as well as after perfusion with low-dose quinacrine (P = 0.0008) at 42 °C. CONCLUSION: Quinacrine has demonstrable efficacy against melanoma cells in vitro and in a clinically relevant model of ILP. Further studies to evaluate the optimal conditions for quinacrine usage are warranted.

Effects of disorder and internal dynamics on vortex wall propagation.

Experimental measurements of domain wall propagation are typically interpreted by comparison to reduced models that ignore both the effects of disorder and the internal dynamics of the domain wall structure. Using micromagnetic simulations, we study vortex wall propagation in magnetic nanowires induced by fields or currents in the presence of disorder. We show that the disorder leads to increases and decreases in the domain wall velocity depending on the conditions. These results can be understood in terms of an effective damping that increases as disorder increases. As a domain wall moves through disorder, internal degrees of freedom get excited, increasing the energy dissipation rate.