scholarly journals The Effect of Wood Type on the Reflection of a Table Tennis Ball

2021 ◽  
Vol 4 (2) ◽  
pp. 210-223
Author(s):  
Bayu Septa Martaviano Triaiditya ◽  
Gatut Rubiono ◽  
Danang Ari Santoso
Keyword(s):  
Specific Gravity ◽  
Coefficient Of Restitution ◽  
Tennis Ball ◽  
Table Tennis ◽  
Initial Height ◽  
Average Value ◽  
Reflection Height ◽  
Teak Wood ◽  
Bounce Height ◽  
Main Material

The table tennis game table can be made of any material with certain bounce height requirements according to ITTF regulations. Wood as the main material for the table is found in Indonesia. Various types of wood have the potential to be a dining table material. This study was conducted to determine the effect of the type of wood on the bounce of a table tennis ball. Experiments were carried out on 9 types of wood, namely hardwoods (teak, sono, coconut), medium hardwoods (meranti, plywood and jackfruit) and soft woods (waru, randu and sengon). The height of the falling ball is determined to be 30 cm for the ball's bounce recorded by the camera. The ball used is a ball with a weight of 24 grams and 30 grams. Camera recording data is processed with Kinovea 08.15 to get the reflection height. The bounce height is used as a reference for ITTF standard compliance. The initial height and reflection height were then used to calculate the coefficient of restitution (COR). Data collection was carried out 5 times and the average value was calculated. The level of wood hardness is influenced by its specific gravity. Hard wood has a relatively high specific gravity. Teak wood which is relatively hard has a specific gravity value of 0.59 – 0.82 gr/cm3

Dynamics of a bouncing table tennis ball from the acoustic signature using an optical fibre sensor

2021 ◽  
Author(s):  
James Farai Jena ◽  
Shukree Wassin ◽  
Tim Gibbon
Keyword(s):  
Undergraduate Students ◽  
Optical Fibre ◽  
Impact Force ◽  
Early Warning Systems ◽  
Coefficient Of Restitution ◽  
Tennis Ball ◽  
Table Tennis ◽  
Optical Fibre Sensor ◽  
Fibre Sensor ◽  
The Impact

Abstract We describe an optical fibre-based method to estimate impact force and collision duration using time measurements recorded from acoustic signals of a table tennis ball bouncing on a table. The technique combines measurements obtained from a polarisation dependent optical fibre sensor with graphical analysis and kinetics through numerical calculations. The presented coefficient of restitution, collision time, impact force, and elastic deformation during each bounce of the table tennis ball were obtained using corresponding time series measurements and numerical analysis. A peak impact force of 38.4N was estimated for a ball of mass 2.83g and 39.7mm diameter dropped from a height of 31.5cm. The impact duration for the associated bounce was 0.68ms with a centre of gravity shift of 0.40mm and coefficient of restitution of 0.88. While the observed results are unique to the ball and table surface, the approach is an attempt to fully quantify collision parameters from basic measurement and instrumentation applicable to undergraduate students. The sensor developed in this paper finds application in sports performance monitoring, infrastructural health early warning systems and pressure sensitive manufacturing processes.

scholarly journals EFFECT OF VARIATIONS OF BETA VULGARIS EXTRACTS ON MASKING THE BITTER TASTE OF MOMORDICA CHARANTIA EXTRACT SYRUP

2018 ◽  
Vol 10 (1) ◽  
pp. 159
Author(s):  
Sutriyo . ◽  
Raditya Iswandana ◽  
Elisa Nur Widiya
Keyword(s):  
Specific Gravity ◽  
Physical Properties ◽  
Beta Vulgaris ◽  
Sodium Benzoate ◽  
Bitter Taste ◽  
Momordica Charantia ◽  
The Other ◽  
Bitter Melon ◽  
Average Value

Objective: This study aimed to obtain a formula with an optimal sweetener concentration of beet extract that can cover the bitter taste of bitter melonand confer optimal physical properties on the syrup.Methods: The syrups were prepared by mixing bitter melon extract, sucrose, beet extract, sorbitol, sodium benzoate, strawberry essence, anddemineralized water. The control formula and formulas 1, 2, and 3 contained beet extract at concentrations of 0% and 10%, 15%, and 20%, respectively.All formulas were evaluated to determine their physical properties, stability, and bitterness. The bitterness was tested on 30 respondents, with databeing analyzed using Wilcoxon’s test on SPSS software.Results and Conclusion: Formula 3 with 20% beet extract was identified as the best formula for masking bitter taste because it had a significantlybetter average value than the other formulas (p<0.05) and the highest bitterless taste percentage (86.67%), with physical properties of a brownishblackcolor, odor of mixture of strawberry and dominant beet, a sweet and dominant beet taste, pH 5.46, and specific gravity of 1.228 g/mL.

scholarly journals Table Tennis Ball Impacting Racket Polymeric Coatings: Experiments and Modeling of Key Performance Metrics

2019 ◽  
Vol 9 (1) ◽  
pp. 158 ◽  
Author(s):  
Renaud G. Rinaldi ◽  
Lionel Manin ◽  
Sébastien Moineau ◽  
Nicolas Havard
Keyword(s):  
Performance Metrics ◽  
Incident Angle ◽  
Mechanical Analysis ◽  
Tennis Ball ◽  
Table Tennis ◽  
Polymeric Coatings ◽  
Compression Tests ◽  
Compliant Behavior ◽  
The Impact

The performance of a table tennis racket is often associated with subjective or quantitative criteria such as the adhesion, the control and the speed. Overall, the so-called performance aims at characterizing the impact with the ball. Ultimately, the polymeric layers glued onto the wooden blade play a key role, as evidenced in a previous work where the normal linear (no spin) impact of a ball onto polymeric layers was experimentally and numerically investigated. In this work, more realistic loading conditions leading to varying the incident angle and spin of the ball, were explored. While the sole linear restitution coefficient was determined in the anterior normal impact study, new physical metrics were identified to describe fully the trajectory of the reflected ball after impact. A companion 3D finite elements model was developed where the polymeric time-dependent dissipative compliant behavior measured with dynamic mechanical analysis and compression tests was accounted for. The confrontations with the experimental data highlighted the key role of the polymer intrinsic properties along with the friction coefficient between the ball and the polymer external layer.

Development of table tennis ball shooting machine with four rollers

2019 ◽  
Vol 2019 (0) ◽  
pp. C-33
Author(s):  
Shinobu SAKAI ◽  
Jin-Xing SHI ◽  
Atsuya TANAKA
Keyword(s):  
Tennis Ball ◽  
Table Tennis
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