Tritium retention in plasma-facing components is a critical issue for fuel-cycle management in fusion reactors, and accurate evaluation of triton impact behavior is essential. To improve the fidelity of triton-wall interaction analysis in the Large Helical Device, we developed a high-accuracy computational and visualization framework that combines STL-based 3D models with VR-enabled representation of triton impact points and impact velocity vectors. D-D fusion born triton production was modeled using FIT3D-DD, and particle orbits were computed with LORBIT. Collision detection with plasma-facing structures was performed with high-resolution triangular mesh models exported from CAD designs. The STL-based wall model eliminated non-physical impact artifacts that appeared in the conventional cross-section-rotation geometry and provided physically consistent distributions of impact points. The visualization of impact velocity vectors within the VR environment enabled detailed qualitative assessment of incident-angle distributions, revealing geometric features−such as directional asymmetry between clockwise and counterclockwise toroidal magnetic field configurations− that cannot be captured by point-based visualization alone. This integrated approach demonstrates the effectiveness of combining precise geometric modeling with immersive VR visualization for interpreting energetic-particle behavior in fusion devices. The framework offers a valuable tool for correlating impact characteristics with material analyses and supports future optimization of plasma-facing component design.

The magnetic fields confining plasma in fusion reactors are analyzed using Poincaré plots, which show intersections of magnetic field lines on a poloidal crosssection. Traditional methods for designing vacuum vessels and related structures involve slicing the reactor vertically and analyzing these plots, but this approach is inefficient for understanding plasma shapes globally. Key challenges include the computational cost of magnetic field line tracing and the difficulty in constructing continuous surfaces for the divertor legs due to the limited number of magnetic field lines reaching this area. To address these issues, a new and automatic method has been proposed to increase the number of magnetic field lines constituting the divertor legs by predicting optimal starting points for tracing. The proposed method involves placing starting points on orthogonal lines through the magnetic axis, resulting in a better representation of divertor legs. This new algorithm enhances the efficiency of generating Poincaré plots that depict divertor leg regions more clearly than previous methods. Neural Networks predict voxel data representing the shape of magnetic field lines. Considering the Larmor radius, we calculate an envelope surface that encompasses the region where plasma exists and create 3D modeling data.

Japanese traditional dance is a performing art with a rich and extensive history. Passed down orally and through demonstration over generations, its intricate movements are often challenging to convey accurately, resulting in subtle changes over time. To address this, efforts are being made to digitize and preserve these culturally significant practices through digital archiving. Furthermore, the number of traditional Japanese dance practitioners is declining yearly, leading to challenges in succession and education. This study employs two motion capture systems to create a digital archive of traditional Japanese dance and to visualize the movement differences between beginners and skilled practitioners. The ultimate goal is to develop a learning support system that aids in the education and training of future practitioners, ensuring the art form’s continuity.

The “up3bd” code, which is an efficient three-dimensional (3D) electrostatic particle-in-cell (PIC) simulation code for study of transport dynamics in fusion boundary layer plasmas or other plasmas in nature, has been tested on various high-performance computing (HPC) systems which consist of different types of processor. The results of benchmark tests indicate that the up3bd code works faster on processors in which cache memory is larger or memory bandwidth is broader. Also, the types of computations that each architecture excels at and struggles with has been revealed.

This study investigates the application of inchworm robots for mobile additive manufacturing (AM). A method for controlling the center of gravity (COG) during locomotion and designing unit segments for efficient fabrication is proposed. The relationship between link lengths and fabrication efficiency was analyzed, and unit segments were designed to balance stability and production efficiency. Simulations were conducted to evaluate the stability of the robot’s locomotion, confirming that the proposed design allows the COG to remain within the supporting leg area. These findings contribute to understanding the feasibility of inchworm robots as platforms for mobile AM systems.

The group-wise updating technique is one of the techniques for improving the accuracy of an approximate solution of Block Krylov subspace methods. This technique improves the accuracy of the approximate solution by grouping update terms of a recurrence relation. However, the number of update terms affects the performance of the Block Krylov subspace methods. This paper proposes a variable grouping strategy that does not fix the number of update terms to be grouped. Moreover, we incorporate the proposed strategy into the Block product-type iterative methods and evaluate its performance through numerical experiments.

The purpose of this study is to introduce a novel mobile Material Extrusion-based Additive Manufacturing (MEAM) machine designed to achieve complex and large scale fabrication without the constraints of size limitations. This is implemented by integrating a MEAM mechanism onto a multi-legged robot. This study also proposes methods for motion and material extrusion planning of the mobile MEAM machine and evaluates these methods through fundamental experiments. The results show that the accuracy of the fabrication is significantly dependent on the effectiveness of the motion planning and the accuracy of the robot control.

The bending and twisting deformations of biopolymers have attracted considerable interests. In this paper, we propose a ladder-type polymer chain minimal model which describes DNA-like polymers' bending and twisting elasticities within the framework of coarse-grained molecular dynamics simulation. Applying the model for a loop extrusion process, which introduces loop and twist on the chain, we obtained the stable twisted loop structures and observed the conversion between bend-elastic and twist-elastic energies. Moreover, we computed the linking number, a topological invariant for wound and twisted structures with fixed ends, and confirmed that the energy conversion proceeds under conservation of the linking number.

In this paper, a simple method is proposed that allows two planar inverted-F antennas (PIFAs) maintain their bandwidth while simultaneously reducing the mutual coupling between them. By creating a slit on each PIFA patch and then connecting the two PIFAs by a bridge line (BL), the bandwidth can be maintained and the mutual coupling between them can be simultaneously reduced to less than －10 dB. Therefore, total antenna efficiency can be significantly improved over a wide band. The proposed model is fabricated and measured, and the simulation results are validated by the measurement results.

We present a minimal version of Landscape Evolution Models (LEMs) to capture the essence of tree-shaped channel network formation on the assumption of two mechanisms, soil erosion and diffusion. The continuous tectonic uplift is not required, which affects landscape evolution only at the starting point. We refer to the mathematical model as the Erosion-Diffusion Model (EDM). No steady state exists in the EDM except for the perfectly flat plane, which is realized at the ultimate final stage of the landform transition. It is suggested that generated channel patterns are temporal and transient creatures during long-term gravitational and erosional processes on the earth.