scholarly journals Bouncing ball impacts

2021 ◽  
Vol 89 (5) ◽  
pp. 452-452
Author(s):  
Rod Cross
Keyword(s):  
Bouncing Ball

scholarly journals A Self-Powered and Highly Accurate Vibration Sensor Based on Bouncing-Ball Triboelectric Nanogenerator for Intelligent Ship Machinery Monitoring

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 218
Author(s):  
Taili Du ◽  
Xusheng Zuo ◽  
Fangyang Dong ◽  
Shunqi Li ◽  
Anaeli Elibariki Mtui ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Work Conditions ◽  
Copper Electrode ◽  
Vibration Sensor ◽  
High Signal ◽  
Triboelectric Nanogenerator ◽  
Vibration Exciter ◽  
Bouncing Ball ◽  
3D Printed ◽  
Self Powered

With the development of intelligent ship, types of advanced sensors are in great demand for monitoring the work conditions of ship machinery. In the present work, a self-powered and highly accurate vibration sensor based on bouncing-ball triboelectric nanogenerator (BB-TENG) is proposed and investigated. The BB-TENG sensor consists of two copper electrode layers and one 3D-printed frame filled with polytetrafluoroethylene (PTFE) balls. When the sensor is installed on a vibration exciter, the PTFE balls will continuously bounce between the two electrodes, generating a periodically fluctuating electrical signals whose frequency can be easily measured through fast Fourier transform. Experiments have demonstrated that the BB-TENG sensor has a high signal-to-noise ratio of 34.5 dB with mean error less than 0.05% at the vibration frequency of 10 Hz to 50 Hz which covers the most vibration range of the machinery on ship. In addition, the BB-TENG can power 30 LEDs and a temperature sensor by converting vibration energy into electricity. Therefore, the BB-TENG sensor can be utilized as a self-powered and highly accurate vibration sensor for condition monitoring of intelligent ship machinery.

The bouncing ball and the Grünwald-Letnikov definition of fractional derivative

2021 ◽  
Vol 24 (4) ◽  
pp. 1003-1014
Author(s):  
J. A. Tenreiro Machado
Keyword(s):  
Fractional Calculus ◽  
Fractional Derivative ◽  
Fractional Order ◽  
Restitution Coefficient ◽  
Classical Physics ◽  
Bouncing Ball ◽  
Mechanical Experiment ◽  
Fractional Models ◽  
Definition Of

Abstract This paper proposes a conceptual experiment embedding the model of a bouncing ball and the Grünwald-Letnikov (GL) formulation for derivative of fractional order. The impacts of the ball with the surface are modeled by means of a restitution coefficient related to the coefficients of the GL fractional derivative. The results are straightforward to interpret under the light of the classical physics. The mechanical experiment leads to a physical perspective and allows a straightforward visualization. This strategy provides not only a motivational introduction to students of the fractional calculus, but also triggers possible discussion with regard to the use of fractional models in mechanics.

Global ballistic acceleration in a bouncing-ball model

2015 ◽  
Vol 92 (1) ◽  
Author(s):  
Tiago Kroetz ◽  
André L. P. Livorati ◽  
Edson D. Leonel ◽  
Iberê L. Caldas
Keyword(s):  
Bouncing Ball

scholarly journals Enhanced DEM-based flow path delineation methods for urban flood modelling

2012 ◽  
Vol 15 (2) ◽  
pp. 568-579
Author(s):  
J. P. Leitão ◽  
D. Prodanović ◽  
S. Boonya-aroonnet ◽  
Č. Maksimović
Keyword(s):  
Urban Areas ◽  
Overland Flow ◽  
Flow Path ◽  
Flow Paths ◽  
Urban Flood ◽  
Bouncing Ball ◽  
Digital Elevation ◽  
Synthetic Test ◽  
Water Accumulation ◽  
Flooding Events

In order to simulate surface runoff and flooding, one-dimensional (1D) overland flow networks can be automatically delineated using digital elevation models (DEM). The resulting network comprises flow paths and terrain depressions/ponds and is essential to reliably model pluvial (surface) flooding events in urban areas by so-called 1D/1D models. Conventional automatic DEM-based flow path delineation methods have problems in producing realistic overland flow paths when detailed high-resolution DEMs of urban areas are used. The aim of this paper is to present the results of research and development of three enhanced DEM-based overland flow path delineation methods; these methods are triggered when the conventional flow path delineation process stops due to a flow obstacle. Two of the methods, the ‘bouncing ball and buildings’ and ‘bouncing ball and A*’ methods, are based on the conventional ‘bouncing ball’ concept; the third proposed method, the ‘sliding ball’ method, is based on the physical water accumulation concept. These enhanced methods were tested and their results were compared with results obtained using two conventional flow path delineation methods using a semi-synthetic test DEM. The results showed significant improvements in terms of the reliability of the delineated overland flow paths when using these enhanced methods.

Quantum coupling between gravity and mass in bouncing ball dynamics

2019 ◽  
Vol 40 (2) ◽  
pp. 025401
Author(s):  
A Feoli ◽  
E Benedetto ◽  
F Feleppa
Keyword(s):  
Bouncing Ball ◽  
Quantum Coupling
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