Watch what you type: The role of visual feedback from the screen and hands in skilled typewriting

Attention, Perception, & Psychophysics - Skilled typing is controlled by two hierarchically structured processing loops (Logan & Crump, 2011): The outer loop, which produces words,...     

Modeling of 1-3 piezoelectric composites operating in thickness-stretch vibration mode

For bulk piezoelectric ceramics plates, the fundamental thickness-stretch (TSt) waves are always coupled to the in-plane extension waves and the symmetric thickness-shear waves. The occurrence of these spurious modes in bulk piezoelectric ceramics plates is undesirable as it may interfere with the operation of transducers. 1–3 piezoelectric composites are promising candidates to suppress the spurious modes mentioned above. However, theoretical modelling of multiphase ceramic composite objects is very complex. In this study, a simple analytical TSt vibration model is constructed from three-dimensional equations of linear piezoelectricity. The mechanical damping is considered in the model by introducing a complex elastic constant. The performance of 1–3 piezoelectric composites is analysed and the electrical impedance results from theoretical and experimental analysis are compared. The results show that there is excellent agreement between the experimental electrical impedance and that obtained by the theoretical TSt vibration analysis. This indicates that 1–3 piezoelectric composites can be operated in a nearly pure TSt vibration mode near the fundamental resonance. The analytical model we present is valid for analysing 1–3 piezoelectric composites plates with large aspect ratios quickly and efficiently.     

Atomic imaging of the interface between M23C6-type carbide and matrix in a long-term ageing polycrystalline Ni-based superalloy

Besides the well-known cube-on-cube orientation relationship (OR) between M₂₃C₆ carbide and matrix, we have determined a new OR named as the twin-related OR in a long-term ageing Ni-based superalloy on the basis of the extensive and detailed electron diffraction analyses. Furthermore, by means of atomic-resolution high angle annular dark-field imaging technique which is implemented in the aberration-corrected scanning transmission electron microscope, we elucidated the interfacial characteristics between M₂₃C₆ and matrix for above two types of ORs. Taking into account of the interfacial characteristics, we propose that the twin-related OR possesses a higher total interfacial energy. Thus, its frequency of occurrence is lower than that of the cube-on-cube OR though both ORs are usually seen in the long-term ageing samples.     

The failure to detect tactile change: A tactile analogue of visual change blindness

A large body of empirical research now shows that people are surprisingly poor at detecting significant changes in visually presented scenes. This phenomenon is known aschange blindness in vision. A similar phenomenon occurs in audition, but to date no such effect has been documented in touch. In the present study, we explored the ability of people to detect changes introduced between two consecutively presented vibrotactile patterns presented over the body surface. The patterns consisted of two or three vibrotactile stimuli presented for 200 msec. The position of one of the vibrotactile stimuli composing the display was repeatedly changed (alternating between two different positions) on 50% of the trials, but the same pattern was presented repeatedly on the remaining trials. Three conditions were investigated: No interval between the patterns, an empty interval between the patterns, and a masked interval between the patterns. Change detection was near perfect in the no-interval block. Performance deteriorated somewhat in the empty-interval block, but by far the worst change detection performance occurred in the masked-interval block. These results demonstrate that “change blindness” can also affect tactile perception.