Evolution of the Shear Band in Cold-Rolling of Strip-Cast Fe-1.3% Si Non-Oriented Silicon Steel

Cube texture and microstructural evolution of as-cast non-oriented silicon steel (1.3% Si) during cold rolling and annealing were studied. The results showed that the as-cast microstructure with grain size in the range of 100–500 μm had a weak texture. The strong orientation was mainly located at {100} and {110} planes. A significant content of shear-deformed grains oriented with {110}<110> were obtained by cold-rolling, and many regions oriented with Cube texture were distributed in the shear bands. During cold-rolling, the orientation of the shear-deformed microstructure tilted towards the {111}<112> orientation, while the matrix orientation retained {110}<110>. On further cold-rolling, the residual part of {110}<110> experienced shear deformation, forming more shear bands, strengthening the Cube orientation. During annealing, Cube orientation grains nucleated in the shear bands leading to strong Cube texture, and corresponding B50 was 1.83T/1.79T.

Characteristics of Cube Orientation for Pure Iron Tape Fabricated by Cold Rolling and Annealing

A pure iron tape with cube orientation was fabricated by cold rolling and annealing. The orientation characteristics of the pure iron tape were evaluated using electron back-scattering diffraction (EBSD) analysis. The secondary recrystallized grains with cube orientation was formed on the tape surface for the pure iron tape. The coarse grains with a grain size of ca. 1mm were observed on the tape surface. The areal fraction of cube orientations with an angular deviation ≤ 20 ̊ amounts to ca. 81%.

Voluntary and Involuntary Attention in Bistable Visual Perception: A MEG Study

In this study, voluntary and involuntary visual attention focused on different interpretations of a bistable image, were investigated using magnetoencephalography (MEG). A Necker cube with sinusoidally modulated pixels' intensity in the front and rear faces with frequencies 6.67 Hz (60/9) and 8.57 Hz (60/7), respectively, was presented to 12 healthy volunteers, who interpreted the cube as either left- or right-oriented. The tags of these frequencies and their second harmonics were identified in the average Fourier spectra of the MEG data recorded from the visual cortex. In the first part of the experiment, the subjects were asked to voluntarily control their attention by interpreting the cube orientation as either being on the left or right. Accordingly, we observed the dominance of the corresponding spectral component, and voluntary attention performance was measured. In the second part of the experiment, the subjects were asked to focus their gaze on a red marker at the center of the cube image without putting forth effort in its interpretation. The alternation of the dominant spectral energies at the second harmonics of the stimulation frequencies was treated as changes in the cube orientation. Based on the results of the first experimental stage and using a wavelet analysis, we developed a method which allowed us to identify the currently perceived cube orientation. Finally, we characterized involuntary attention using the distribution of dominance times when focusing attention on one of the cube orientations, which was related to voluntary attention performance and brain noise. In particular, we confirmed our hypothesis that higher attention performance is associated with stronger brain noise.

Estimating voluntary and involuntary attention in bistable visual perception: A MEG study

We introduce a method for measuring human attention when performing a visual task consisting in different interpretations of a bistable image. The Necker cube with flickering faces was presented to nine conditionally healthy volunteers. The pixels intensity in the front and rear cube faces were modulated by a sinusoidal signal with 6.67-Hz (60/9) and 8.57-Hz (60/7) frequencies, respectively. The tags of these frequencies and their second harmonics were clearly identified in the average Fourier spectra of the magnetoencephalographic (MEG) data recorded from the occipital cortex. In the first part of the experiment, the subjects were asked to voluntary control their attention by interpreting the cube orientation as either left- or right-orientated. Accordingly, we observed the dominance of the corresponding spectral component and voluntary attention performance was measured. In the second part of the experiment, the subjects were just asked to observe the cube image without any effort in its interpretation. The alternation of the dominant spectral energies at the second harmonic tag frequencies was treated as changes in the cube orientation. Based on the results of the first experimental stage and using wavelet analysis, we developed a novel method which allowed us to identify currently perceived cube orientations. Finally, we characterized involuntary attention using the dominance time distribution and related it to voluntary attention performance and brain noise. In particular, we have shown that higher attention performance is associated with stronger brain noise.

A study of the effect of projectile orientation on the results of ballistic impact tests as described in the EASA CS-25 regulations for fuel tank access covers

This paper presents the results of an investigation of the ballistic limits and failure modes of AA2024-T351 sheets impacted with cubical projectiles. The experiment/test setup was based on EASA CS-25 regulations for fuel tank access covers. The effect of cube orientation on the ballistic limit and failure modes was considered in detail. A 25% variation in ballistic limit was observed with the lowest ballistic limit (202 m/s) observed for the cubical projectile edge impacted on the target. In the cube face impacts, the ballistic limit was higher (223 m/s), and the highest ballistic limit (254 m/s) was observed for the corner impact. The observed differences in the ballistic limit were due to differences in failure mechanism, which resulted in different localised deformations near the projectile impact point, but also led to differences in global dishing deformation.