Visual speed sensitivity in the drum corps color guard.

World class drum corps require cooperation among performance artists to render precisely synchronized and asynchronized events. For example, drum corps visual aesthetics often feature salient radial and rotational motion displays from the color guard. Accordingly, extensive color guard training might predict superior visual timing sensitivity to asynchronies in radial and rotational motion displays. Less intuitively, one might instead predict superior visual timing sensitivity among world class drum corps musicians, who regularly subdivide musical tempos into brief time units. This prediction arises from the possibility that auditory training transfers cross-modally. Here, we investigated whether precise visual temporal order judgments (TOJs) more strongly align with color guard's visual training or musicians' auditory training. To mimic color guard visual displays, stimuli comprised bilateral plaid patterns that radiated or rotated before changing direction asynchronously. Human participants indicated whether the direction changed first on the left or right, called a TOJ. Twenty-five percussionists, 67 brass players, and 29 color guard members from a world class drum corps collectively completed 67,760 visual TOJ trials. Percussionists exhibited significantly lower TOJ thresholds than did brass players, who exhibited significantly lower TOJ thresholds than did the color guard. Group median thresholds spanned an order of magnitude, ranging between 29 ms (percussionists judging rotational asynchronies) and 290 ms (color guard judging radial asynchronies). The results suggest that visual timing can improve more by training cross-modally than intramodally, even when intramodal training and testing stimuli closely match. More broadly, pre-existing training histories can provide a unique window into the timing sensitivity of the nervous system.

Neurophysiological experiments have shown that a shared region of the primate visual system registers both radial and rotational motion. Radial and rotational motion also share computational features. Despite these neural and computational similarities, prior experiments have disrupted radial, but not rotational, motion sensitivity -a single dissociation. Here we report stimulus manipulations that extend the single dissociation to a double dissociation, thereby showing further separability between radial and rotational motion sensitivity. In Exp 1 bilateral plaid stimuli with or without phase-noise either radiated or rotated before changing direction. College students reported whether the direction changed first on the left or right–a temporal order judgment (TOJ). Phase noise generated significantly larger disruptions to rotational TOJs than to radial TOJs, thereby completing the double dissociation. In Exp 2 we conceptually replicated this double dissociation by switching the task from TOJs to simultaneity judgments (SJs). Phase noise generated significantly larger disruptions to rotational SJs than to radial SJs. This disruption pattern reversed after changing the plaids’ motion from same- to opposite-initial directions. The double dissociations reported here revealed distinct dependencies for radial and rotational motion sensitivity. Radial motion sensitivity depended strongly on information about global depth. Rotational motion sensitivity depended strongly on positional information about local luminance gradients. These distinct dependencies arose downstream from the neural mechanisms that detect local linear components within radial and rotational motion. Overall, the differential impairments generated by our psychophysical experiments demonstrate independence between radial and rotational motion sensitivity, despite their neural and computational similarities.

The medial superior temporal (MST) area contains neurons with tuning for complex motion patterns, but very little is known about the generation of such responses. To explore how neuronal responses varied across complex motion pattern coherence, we recorded from single units while varying the strength of the global motion pattern in random dot stimuli. Stimuli were a family of optic flow patterns, consisting of radial motion, rotary motion, or combinations thereof ("spiral space"). We controlled the strength of the motion in the stimuli by varying the coherence--the proportion of dots carrying the signal. This allows motion strength to be varied independently of stimulus size, speed, or contrast. Most neurons' responses were well described as a linear function of stimulus coherence. Although more than half the cells possessed significant nonlinearities, these typically accounted for little additional variance. Nonlinear coherence response functions could either be compressive (e.g., saturating) or expansive and occurred in both the preferred and null direction responses. The presence of nonlinearities was not related to neuronal response properties such as preferred spiral-space direction or tuning bandwidth; however, cells with compressive nonlinearities in both the preferred and null directions tended to have higher response amplitudes and were more sensitive to weak motion signals. These cells did not appear to form a distinct subpopulation within MST. Our results suggest that MST neurons predominantly linearly encode increasing pattern motion energy within their RFs.

Research has found circular and rotational motion to be a challenging topic for undergraduate physics students. This article reports on Introductory Physics students’ learning of concepts and quantitative principles in circular and rotational motion. It involves a teaching strategy that uses hands-on practical work, PhET simulations and a focus on feedback in line with the Active Learning Theory developed by Chi and colleagues. Data in this study were collected via in-depth interviews, end-of-lesson tasks and questionnaires. After the intervention, most students were able to show understanding of the relationship between velocity (linear and angular) and radius, predict the motion of a car at a curve given the velocity and show understanding of the relationships between mass distribution and moment of inertia. They considered that hands-on practical work facilitated the derivation of equations and establishing of relationships whereas the accompanying group discussions provided opportunities for justifying developing conceptual understanding. The strengths of the use of PhET simulations were seen as the visualisation of vector directions, the opportunities to confirm predictions and the perceived high reliability of the measurements. The study also showed that feedback was perceived to contribute positively towards the ability to derive equations and relate concepts and even promote self-regulation practices. All in all, this study revealed that a complementary combination of hands-on practical work, free internet-based resources such as PhET simulations and a focus on feedback helps Introductory Physics students learn concepts and quantitative principles in the physics topic of circular and rotational motion.

Traditional ultrasonic motors can usually produce either linear or rotational motion. Piezoelectrically driven structures with multiple degrees of freedom require two or more ultrasonic motors, and the manufacturing process is associated with some problems related to their complex structure and difficult control. This study proposes a new structure of a multi-degree-of-freedom piezoelectric crawling robot. Four modes are selected as the working modes, and mode superposition is used to produce the linear and rotational motion of the robot. This structure is designed based on a combination of size and topological optimization to adjust the frequency response consistency of the motor. The performance of the motor was tested on surfaces with different roughnesses. Its performance on the desk surface was the best. Its maximum linear speed is 37 mm/s, and its maximum rotational speed is 6.28 rad/s. The performance tests were performed under different loads. The linear motion speed of the motor reached its maximum value at 29.2 kHz, and the rotational motion speed reached its maximum value at 32.1 kHz.

A concept for a 2-degree-of-freedom (DOF) mobile robot is proposed, and its design and experimental study are conducted. The robot achieves linear motion along the x -axis and rotational motion along the z -axis using only two serial inertial impact devices vibrators driven by inertial impact forces. Flexible hinge mechanisms of the 2-DOF piezoelectric robot are simulated using ANSYS Workbench by varying structural parameters. Dynamic equations are established, and a dynamic simulation model is built using MATLAB/Simulink to output performance simulations. A prototype is produced, and the drive waveform, voltage amplitude, and frequency are adjusted in experiments to study the linear movement speed, rotational movement speed, and displacement accuracy of the linear and rotational movements of the piezoelectric robot. Its 2-DOF motion performance was verified, and the results are compared with the dynamic simulation results to analyze the rationality of the model. Based on a more compact and sophisticated structural design, this concept enables the 2-DOF motion of a piezoelectric robot, providing a new technical path for the design of piezoelectric-driven multi-DOF robots and verifying the feasibility and effectiveness of the inertial configuration in terms of motion accuracy and mechanism simplification. Experimental results show that the device maintains stable performance under drive voltages ranging from 10 to 140 Vp–p. Under drive conditions of 10 V and 1 Hz, the maximum linear movement accuracy of the drive device is 0.26 μ m. At 100 V and within the test frequency range, the maximum movement speed is 16.223 mm s −1 . Under 9 Hz conditions, the maximum operating speed is 1.06 mm s −1 , demonstrating excellent motion speed performance. Under driving conditions of 100 V and 11 Hz, the maximum rotational movement speed of the drive device is 11.73 μ rad s −1 .

An angular motion feedthrough capable of supporting a large diameter linear motion feedthrough has been designed and built for the large experiment on instabilities and anisotropies at West Virginia University. With a combination of linear, angular, and rotary motion, a probe can be positioned in the vacuum chamber within a cone-shaped volume.

Rotational movement is important in many applications, yet has been under-explored. In this paper, we explore the feasibility of using a single RFID reader antenna to simultaneously sense rotation and translation movement (i.e., rotation axis, rotation speed, and translation speed). We exploit the polarization in RFID to enable motion sensing. We develop an analytical model to capture the impact of polarization on the received signal and an optimization framework to incorporate the model to estimate the movement. We implement our system, Tag-based Inertial Measurement Unit (TIMU), and demonstrate its effectiveness through an extensive evaluation. To our knowledge, this is the first system that tracks general motion using a single RFID reader antenna.

Computer vision techniques can monitor the rotational speed of rotating equipment or machines to understand their working conditions and prevent failures. Such techniques are highly precise, contactless, and potentially suitable for applications without massive setup changes. However, traditional vision sensors collect a significant amount of data to process and measure the rotation of high-speed systems, and they are susceptible to motion blur. This work proposes a new method for measuring rotational speed processing event-based data applied to high-speed systems using a neuromorphic sensor. This sensor produces event-based data and is designed to work with high temporal resolution and high dynamic range. The main advantages of the Event-based Angular Speed Measurement (EB-ASM) method are the high dynamic range, the absence of motion blurring, and the possibility of measuring multiple rotations simultaneously with a single device. The proposed method uses the time difference between spikes in a Kernel or Window selected in the sensor frame range. It is evaluated in two experimental scenarios by measuring a fan rotational speed and a Router Computer Numerical Control (CNC) spindle. The results compare measurements with a calibrated digital photo-tachometer. Based on the performed tests, the EB-ASM can measure the rotational speed with a mean absolute error of less than 0.2% for both scenarios.

New micro tribometer for rolling friction

This paper presented a“Z” shape Au/Pt hybrid micro-nanorobot propelled by self electrophoresis driving. The Z shape hybrid micro-nanorobot realized itself rotational movement while having a parallel shift. The Z shape micro-nanorobot was designed for the drug delivery, biomedical engineering and so on. Just as its name implies, the mainly raw materials are platinum and gold. By the focus ion beam (FIB) and plasma sputtering, the Z shape nanorobot was fabricated. In order to validate the fabrication method, the researchers adopted the Energy dispersive X-ray analysis (EDS) to check the purity of Pt and Au hybrid nanorobot inside the environmental scanning electron microscope. Once the Z shape nanorobot was put into the hydrogen peroxide (H2O2) solution, through the inverted optical microscope, a rotational movement which kept accordance with the analysis of the researchers was achieved. After the rotational movement of nanorobot is realized, the concentration of H2O2influence on the movement of nanomotor was evaluated. The nanorobot was put into the concentration rising from 3.0% to 7.6%, and then the average rotation speed of nanorobot increased from 7rpm to 19rpm. Finally, the conclusion was got from the article: 1) the Z shape Au/Pt hybrid micro-nanorobot realized itself rotational movement while having a parallel shift; 2) higher concentration the hydrogen peroxide solution was, stronger propulsion force was generated. Thus the nanorobot had a higher speed of rotational movement.

Experiment study on traveling wave resonance of fatigue fracture of high-speed bevel gear in aero-engne based on acoustic measurement method

An experimental study of a granular surface submitted to a circular fluid motion is presented. The appearance of an instability along the sand-water interface is observed beyond a critical radius r(c). This creates ripples with a spiral shape on the granular surface. A phase diagram of such patterns is constructed and discussed as a function of the rotation speed omega of the flow and as a function of the height of water h above the surface. The study of r(c) as a function of h, omega, and r parameters is reported. Thereafter, r(c) is shown to depend on the rotation speed according to a power law. The ripple wavelength is found to decrease when the rotation speed increases and is proportional to the radial distance r. The azimuthal angle epsilon of the spiral arms is studied. It is found that epsilon scales with homegar. This lead to the conclusion that epsilon depends on the fluid momentum. Comparison with experiments performed with fluids allows us to state that the spiral patterns are not the signature of an instability of the boundary layer.

Far-infrared bandshapes and angular motion of HCl, H2O and D2O in solutions

Introduction:Inadequate spinal motion restriction in patients suffering from spinal injuries could lead to further neurological damage, ultimately worsening their prognosis. This study aimed to investigate the efficacy of long spinal boards (LSB), ske stretcher, and vacuum mattress for cervical spine immobilization during transportation of patients by measuring the angular motion of the cervical spine following lifting, transferring, and tilting. Methods:We conducted an experimental study using a box of three randomizations and crossover designs without a washout period effect for the long spinal board, sked stretcher, and vacuum mattress. We concealed the randomization with sequentially numbered, opaque, sealed envelopes (SNOSE). Kinematic data were collected using eight optoelectronic cameras at 200 Hz (BTS Bioengineering, Milan, Italy) in triangular planes (lateral bending, flexion-extension, and axial rotation) while performing all three motions (static lift-hold, transfer, and 90° tilt).Results:12 cases (7 males and 5 females) with the mean age of 20 ± 3.03 (range: 18-28) years were studied. The three highest angular motions were observed in the axial rotation plane during patient’s tilting under immobilization on all devices (Vacuum mattress having the highest value of 99.01±8.93, followed by the LSB at 89.89±34.35 and the sked stretcher at 86.30±7.73 degrees). During patient lifting, a higher angular motion was observed with vacuum mattress immobilization in flexion extension (Coefficient = 4.45; 95%CI: 0.46 – 8.45; p =0.029) and axial rotation (Coefficient = 3.70; 95%CI: 0.58 – 6.81; p =0.020) planes. During patient transfer, a higher angular motion was observed with sked stretcher in the flexion-extension plane (Coefficient = 2.98; 95%CI: 0.11 – 5.84; p = 0.042). During patient tilting to 90 degrees, a higher angular motion was observed with vacuum mattress immobilization in lateral bending (Coefficient = -4.08; 95%CI: -7.68 - -0.48; p = 0.026) for the vacuum mattress. Conclusion:Based on the finding of the present study, patients on the vacuum mattress experience significantly higher angular motion in flexion extension and axial rotation during lifting, as well as lateral bending during 90-degree tilting. In addition, patients on the sked stretcher showed significantly higher angular motion in flexion-extension during the transferring. However, the predictive margins for immobilization across all devices did not demonstrate clinically significant differences among the three immobilization devices.