OPTOELECTRONIC DEVICES APPLICATION FOR FOREST SEEDS SEPARATION

With the development of optoelectronic technologies, it became possible to use a qualitative criterion for seed separation – their spectrometric properties, reflecting the degree of viability and germination. In the detection system of optoelectronic devices, it is possible to achieve a complete absence of mechanical interaction with the seed.

MECHANICAL INTERACTION OF THE RAIL TRANSPORT CAR AND JOINT IRREGULARITY

Mechanical models of a transport system “carriage - track” while crossing a joint irregularity are proposed. An investigation was conducted on the peculiarities of static, shock and dynamic interaction between the four-axle car and the track, considering tram wheelsets motion features over joint irregularity. A method to solve the equations of a mathematical model of static, shock and dynamic interaction is developed. Numerical analysis is used to determine deflections of the facing rail under the first sleeper for each phase of motion depending on motion phases, and car load and speed.

Adapting the visuo-haptic perception through muscle coactivation

While the nervous system can coordinate muscles’ activation to shape the mechanical interaction with the environment, it is unclear if and how the arm’s coactivation influences visuo-haptic perception and motion planning. Here we show that the nervous system can voluntarily coactivate muscles to improve the quality of the haptic percept. Subjects tracked a randomly moving visual target they were physically coupled to through a virtual elastic band, where the stiffness of the coupling increased with wrist coactivation. Subjects initially relied on vision alone to track the target, but with practice they learned to combine the visual and haptic percepts in a Bayesian manner to improve their tracking performance. This improvement cannot be explained by the stronger mechanical guidance from the elastic band. These results suggest that with practice the nervous system can learn to integrate a novel haptic percept with vision in an optimal fashion.

Left bundle branch block causes left atrial dyssynchrony: a result of atrio-ventricular mechanical interaction

Introduction Left bundle brach block (LBBB) leads to left ventricular (LV) mechanical dyssynchrony with septal flash and delayed lateral wall contractions. Since atrium and ventricle are anatomically connected, dyssynchronous LV contractions may be transmitted to the left atrium, thereby disturbing left (LA) function. Purpose To test the hypothesis that patients with LBBB have LA dyssynchrony induced by tethering to the dyssynchronous left ventricle. Methods Myocardial strain was measured by speckle-tracking echocardiography in 20 non-ischaemic heart failure patients with LBBB, before and 6 months after cardiac resynchronization therapy (CRT), and in 20 healthy controls. For the LA, dyssynchrony was measured as time delay between onset of the interatrial septum and the lateral wall, and for the LV, between onset septal flash and onset lateral wall contraction. White arrows in Figure indicate onset LA stretch. Results As shown in the Figure, patients with LBBB and HF had marked LA reservoir phase dyssynchrony. Before CRT time delay from onset LA septal stretch to onset lateral wall stretch was 125±71 ms (mean±SD), and decreased to 23±70 (p<0.0001) with CRT. In controls there was a small delay of 34±56 ms. The LA dyssynchrony correlated with LV dyssynchrony (r=0.50, p=0.033), supporting the hypothesis that LA dyssynchrony in LBBB represents mechanical interaction due to tethering between the respective walls. Conclusions Patients with LBBB had marked LA reservoir phase dyssynchrony, which was abolished with CRT. The LA dyssynchrony was attributed to direct LV-LA mechanical interaction. The observed LA resynchronization by CRT represent an additional benefit of CRT in patients with heart failure. FUNDunding Acknowledgement Type of funding sources: None. Left atrial and ventricular dyssynchrony