Junction temperature of SiC DMOSFETs at device failure in unclamped inductive switching test has been estimated to be 960 K, and mechanism of the avalanche failure was discussed. The junction temperature was estimated from the extrapolation of temperature dependence of avalanche voltage. The estimated junction temperature was too low for SiC to behave as an intrinsic semiconductor, which suggests the failure occurred not in semiconductor, but in other materials such as oxides and electrode metals.

We performed 1.5-dimensional simulation for the Fokker-Planck equation using the CIP (cubic-interpolated propagation/constrained interpolation profile) method to investigate femtosecond-laser heating and transport processes. We found that the heat flux in the solid part approaches the Spitzer-Härm theory on quite a short time scale ${\omega }_{p}t<\mathrm{}50,$ and thus the subsequent evaporation process can be analyzed by classical thermal conduction. On the basis of this result, we performed a hydrodynamic simulation using the CIP method with classical thermal conduction in order to investigate the long time behavior of the evaporation process. The experimental ablation depth was replicated very well, showing that even femtosecond pulse laser processing can be satisfactorily described by classical heat conduction. Since the damage size is shown to be much larger than laser-spot size even in such an ultrashort-pulse experiment, we must use the fluence estimated by the damage size, which is twice as large as the laser spot, to correctly replicate the experiments.

Spatiotemporal changes in waterborne disease risk were evaluated for the Chhnok Tru floating village in the Tonle Sap Lake by combining a hydraulic simulation and quantitative microbial risk assessment (QMRA). First, a three-dimensional (3D) hydraulic simulation was performed, and the transport of Escherichia coli (E. coli) was simulated. Prior to the simulation, by coupling satellite imagery analysis using the normalized difference water index (NDWI) and a sounding survey using an acoustic Doppler current profiler (ADCP), a new digital elevation model was generated for the complex channel network with high resolution. The results of the 3D hydraulic simulation revealed the flow regime and nonuniform pathogen distribution in the floating village. QMRA was performed for the village using the E. coli distribution calculated by the 3D hydraulic model. Subsequently, the disease risk in the village was visualized through an effective and easy-to-understand disease risk map. To demonstrate the usefulness of the hydraulic-simulation-based disease risk map, the map was used to quantitatively compare simple policies by evaluating their reduction in disease risk.

Information of impact force is expected to assist in trauma severity evaluation for snow avalanche accidents. The study employed a coupled human-snow avalanche model to simulate the impact force on a movable human body in several snow avalanche conditions. The simulation results with the movable body had a smaller impact force than the fixed one, which might be due to a part of the impact energy from the snow avalanche transferring to the movement of the human body. The body motion differed in various flow conditions. It was categorized by flow depth into push, crash, and slip types, corresponding to deep, intermediate, and shallow depths. Their energy ratios were correlated with the Froude number, showing the linear relation in the push type, the independent relation in the crash type, and the exponential relation in the slip type. The empirical equation of the energy ratio for each motion type was proposed finally and expected to help assess the injury and vulnerability of snow avalanches for people in the backcountry.