Ground-state phase diagram of the Kondo lattice model on triangular-to-kagome lattices

We investigate the ground-state phase diagram of the Kondo lattice model with classical localized spins on triangular-to-kagome lattices by using a variational calculation. We identify the parameter regions where a four-sublattice noncoplanar order is stable with a finite spin scalar chirality while changing the lattice structure from triangular to kagome continuously. Although the noncoplanar spin states appear in a wide range of parameters, the spin configurations on the kagome network become coplanar as approaching the kagome lattice; eventually, the scalar chirality vanishes for the kagome lattice model.Comment: 7 pages, 3 figure

Finite Element Modelling of Bends and Creases during Folding Ultra Thin Stainless Steel Foils

Finite Element Modelling of an ultra thin foil of SUS 304 stainless steel is carried out. These foils are 20 mm and below in thickness. The development of stresses and strains during folding of these foils is studied. The objective of this study is to induce qualities of paper in the foils of stainless steel such that a public sculpture of origami can be built with the foil. Finite Element modelling of the fold, reverse fold, junctions of multiple folds as well as the finger-dents are carried out to quantify the extent of straining the steel foil would undergo while an object of origami is folded with it. It is important to know the extent of straining the foil would undergo during folding operation. With this knowledge, the through-thickness microstructure and microtexture can be studied which influence the fracture toughness and low cycle fatigue properties of the steel foil. The foil with the requisite qualities of paper can then be manufactured

Large deformation analysis of ground with wall movement or hallow foundation under extremely low confining pressure using PIV

Large-scale natural disasters have occurred frequently in recent years. In such disasters, large ground deformation has been a recurring phenomenon. As it directly affects the structure, has dureable design is necessitated to minimize the damages. Additionally, the fracture process zones are predicted using numerical analysis, and thereafter, the results of the analysis are validated after comparison with the experimental ones. In this study, image analysis is performed using particle image velocimetry (PIV), and subsequently, the analysis results are validated by the comparison. We herein aim to improve the precision of the image-analysis results, and examine the experimental or analytical condition of reproducing the deformation

Numerical study on load-settlement relationships of shallow foundation under extremely low confining pressure

In order to investigate the ground behavior under shallow foundation with extremely low confining pressure, numerical analysis has been performed using the Material Point Method. Material Point Method is one of particle-based methods but it still uses numerical grid. It has been applied to many problems of geomaterial since it was proposed for the first time. The authors focus on the robustness of the method under large deformation problem and applied it to the shallow foundation problem of geomaterial. In this paper, the formulation and implementation of Material Point Method are described, followed by verification and validation for the implemented code. Then, the parametric investigations on ground behavior under shallow foundation have been carried out

DEM slope-failure analysis of the Minami-Aso / Tateno area during the 2016 Kumamoto earthquakes

The Kumamoto earthquakes, which occurred on April 16, 2016, included deep large-scale landslides in the Minami-Aso village / Tateno area; the Aso Bridge collapsed completely because of this slope failure. Aso Bridge is considered to have collapsed for various reasons, e.g., fault displacements, earthquake accelerations, and landslide sediment depositions on the bridge. In this study, the possibility of landslide-sediment depositions on the bridge was assessed as a reason for the bridge collapse using the discrete element method (DEM), and the landslides at Aso Bridge were reproduced. An experiment and analysis were conducted on the large deformation of aluminum-bar laminated ground with wall movement, to confirm the applicability of DEM to large ground-deformation problems. Next, the Aso Bridge slope-failure analysis was carried out, based on different analysis conditions, and the sediment distribution was compared with field observation results from qualitative and quantitative viewpoints. It was concluded that sediment deposition on the bridge was not a cause of the Aso Bridge failure

Pulse-density-modulated power control of a 4 kW, 450 kHz voltage-source inverter for induction melting applications

This paper presents a 4 kW, 450 kHz voltage-source inverter with a series resonant circuit for induction melting applications, which is characterized by the power control based on pulse density modulation (PDM). The pulse-density-modulated inverter makes an induction melting system simple and compact, thus leading to higher efficiency. A modulation strategy is proposed to realize the induction melting system capable of operation at the frequency and power level of interest. Some interesting experimental results are shown to verify the validity of the concept </p

One-dimensional transport in polymer nanofibers

We report our transport studies in quasi one-dimensional (1D) conductors - helical polyacetylene fibers doped with iodine and the data analysis for other polymer single fibers and tubes. We found that at 30 K < T < 300 K the conductance and the current-voltage characteristics follow the power law: G(T) ~ T^alpha with alpha ~ 2.2-7.2 and I(V) ~ V^betta with betta ~ 2-5.7. Both G(T) and I(V) show the features characteristic of 1D systems such as Luttinger liquid or Wigner crystal. The relationship between our results and theories for tunneling in 1D systems is discussed.Comment: 11 pages, 3 figures, accepted for publication in Phys. Rev. Letter