Mean curvature effect on the response and failure of round-hole tubes submitted to cyclic bending

This paper presents an experiment and analysis to investigate the response and failure of 6061-T6 aluminum alloy round-hole tubes with different hole diameters of 2, 4, 6, 8, and 10 mm subjected to cyclic bending at different curvature ratios of −1.0, −0.5, 0.0, and +0.5. The curvature ratio is defined as the minimum curvature divides by the maximum curvature. Four different curvature ratios are employed to highlight the mean curvature effect. It can be seen from the experimental results that the moment-curvature relationships gradually relax and become steady states after a few bending cycles for curvature ratios of −0.5, 0.0, and +0.5. The ovalization-curvature relationship depicts an asymmetrical, ratchetting and increasing as the number of bending cycles increases for all curvature ratios. In addition, for each hole diameter, the relationships between the curvature range and the number of bending cycles necessary to initiate failure on double logarithmic coordinates display four almost-parallel straight lines for four different curvature ratios. Finally, this paper introduces an empirical formula to simulate the above relationships. By comparing with experimental results, the analysis can reasonably describe the experimental results.

Preference for paintings is also affected by curvature

Preference for curvature has been demonstrated using many types of stimuli, but it remains an open question whether curvature plays a relevant role in responses to original artworks. To investigate this, a novel set of paintings was created, consisting of 3 variations—curved, sharp-angled, and mixed—of the same 16 indeterminate subjects. The present research aimed to differentiate between liking and wanting decisions. We assessed liking both online (study 1) and in the lab (study 2, task 2), using a continuous slider and a dichotomous forced choice, respectively. In both tasks, participants assigned higher ratings to the curved compared to the sharp-angled version of the paintings. Similarly, when participants were explicitly asked if they wanted to take the paintings home, they assigned higher wanting ratings to the curved version (study 2, task 3). However, when they were asked to act as a curator and select works they wanted for their gallery (study 2, task 4) and to make a physical effort to visually consume the painting (implicit wanting; study 2, task 1), no significant difference was found between the 3 sets of paintings. Finally, we found that explicit wanting decisions predicted liking for paintings, while implicit wanting and explicit liking predicted explicit wanting of the artworks in both the home and art contexts. This confirmed that it is possible to differentiate between liking and wanting responses to artistically relevant stimuli. We conclude that this theoretical distinction helps to explain previous conflicting results on the curvature effect, establishing a new line of research in the field of empirical aesthetics.

Investigation of artifacts by mapping SAR in thermoacoustic imaging

Microwave-induced thermoacoustic imaging (MI-TAI) remains one of the focus of attention among biomedical imaging modalities over the last decade. However, the transmission and distribution of microwave inside bio-tissues are complicated, thus result in severe artifacts. In this study, to reveal the underlying mechanisms of artifacts, we deeply investigate the distribution of specific absorption rate (SAR) inside tissue-mimicking phantoms with varied morphological features using both mathematical simulations and corresponding experiments. Our simulated results, which are confirmed by the associated experimental results, show that the SAR distribution highly depends on the geometries of the imaging targets and the polarizing features of the microwave. In addition, we propose the potential mechanisms including Mie-scattering, Fabry-Perot-feature, small curvature effect to interpret the diffraction effect in different scenarios, which may provide basic guidance to predict and distinguish the artifacts for TAI in both fundamental and clinical studies.