Determination of the friction coefficient of an inclined plane using the Doppler effect and smartphones

2020 ◽  
Vol 55 (6) ◽  
pp. 065015
Author(s):  
Praveen Pathak ◽  
Yogita Patel
Keyword(s):  
Friction Coefficient ◽  
Doppler Effect ◽  
Inclined Plane ◽  
The Doppler Effect

A METHOD FOR THE DETERMINATION OF THE KINETIC FRICTION COEFFICIENT IN FRICTION PAIRS BASED ON DIRECT ACCELERATION MEASUREMENT OF AN OBJECT ON AN INCLINED PLANE

Tribologia ◽  
2019 ◽  
Vol 284 (2) ◽  
pp. 57-64
Author(s):  
Wacław Gawędzki ◽  
Mirosław Socha
Keyword(s):  
Friction Coefficient ◽  
Measurement Errors ◽  
Laboratory Experiments ◽  
Kinetic Friction ◽  
Test Rig ◽  
Inclined Plane ◽  
Acceleration Measurement ◽  
Steel Cast ◽  
Theoretical Foundations

The paper presents and experimentally verifies a method for the determination of the kinetic friction coefficient of friction pairs. The method involves a direct acceleration measurement of an object sliding down an inclined plane and the determination of the momentary friction force based on acceleration. The laboratory test rig was presented and the theoretical foundations of the method were discussed in detail. The laboratory experiments were conducted for the following material pairs: steel-cast iron, steel-bronze, and for various inclined plane angles. The experiments results were presented, acceleration vs. time curves were plotted, and friction coefficients were determined. These values were compared to the values known from literature [L. 1–3]. The uncertainly analysis of kinetic friction coefficient determination was conducted. The method effectiveness and accuracy was verified, noting the sources of possible measurement errors and the ways to eliminate them.

scholarly journals Importance of the Doppler effect for the determination of the deuteron binding energy

1999 ◽  
Vol 59 (6) ◽  
pp. 3473-3476 ◽  
Author(s):  
Yongkyu Ko ◽  
Myung Ki Cheoun ◽  
Il-Tong Cheon
Keyword(s):  
Binding Energy ◽  
Doppler Effect ◽  
Deuteron Binding Energy ◽  
The Doppler Effect

scholarly journals Determination of The Rotational Friction Coefficients of Solid Cylinder with Various Inclined Plane Angle

2019 ◽  
Vol 15 (1) ◽  
pp. 52-59
Author(s):  
T. Firdaus ◽  
M. Toifur ◽  
Y. Pramudya
Keyword(s):  
Friction Coefficient ◽  
Learning Activities ◽  
Kinetic Friction ◽  
Plane Angle ◽  
Solid Cylinder ◽  
Inclined Plane ◽  
Friction Coefficients ◽  
Experimental Learning ◽  
Aluminum Cylinder

The layer texture differences of an object have an influence on the friction force caused by both planes. This research aims to determine the static and kinetic friction coefficient on several solid cylinder materials. The benefits of this research can be used to develop experimental learning activities on friction coefficient. This research used experimental method. The research was carried out by rolling samples at various inclined plane angles and measuring the traveled distance traveled in one rotation (D). The results showed that the static and kinetic friction coefficients between aluminum cylinder and glass were 0.146 and 0.097, iron cylinder and glass were 0.136 and 0.096, glass cylinder and brass were 0.132 and 0.094, nylon cylinder and glass were 0.101 and 0.090, and stainsless cylinder and glass were 0.122 and 0.094, respectively.Perbedaan tekstur lapisan sebuah benda mempunyai pengaruh pada gaya gesek yang ditimbulkan oleh kedua bidang. Penelitian ini bertujuan untuk menentukan nilai koefisien gesek statis dan koefisien gesek kinetik pada beberapa bahan silinder pejal. Manfaat yang dapat diambil dari hasil penelitian ini adalah dapat digunakan sebagai mengembangkan kegiatan pembelajaran praktikum koefisien gesekan benda. Penelitian ini menggunakan metode eksperimen. Penelitian dilaksanakan dengan menggelindingkan sampel pada berbagai sudut kemiringan dan mengukur jarak tempuh untuk satu kali putaran (D). Hasil penelitian menunjukkan bahwa nilai koefisien gesek statis dan koefisien gesek kinetik secara berurutan untuk silinder aluminium dengan kaca sebesar 0,146  dan 0,097,  untuk silinder besi dengan kaca sebesar 0,136 dan 0,096, untuk silinder kuningan dengan kaca 0,132 dan 0,094, untuk silinder nylon dengan kaca sebesar 0,101 dan 0,090, dan untuk stainsless dengan kaca sebesar 0,122 dan 0,094.

scholarly journals On the Doppler effect in radar

Radiotekhnika ◽  
2021 ◽  
pp. 93-98
Author(s):  
O.V. Ryazantsev ◽  
S.V. Мarchenko ◽  
M.V. Kulik
Keyword(s):  
Doppler Shift ◽  
Doppler Effect ◽  
Beat Frequency ◽  
Radial Component ◽  
Engineering Systems ◽  
Total Speed ◽  
Radar Station ◽  
Doppler Effects ◽  
The Doppler Effect

The possibilities of simultaneous use of the longitudinal and transverse Doppler effects have been analyzed, and expressions have been derived for the corresponding beat frequencies between the emitted and received signals. As a rule, only the longitudinal Doppler effect is used in modern radio engineering systems, which makes it possible to determine the radial component of the object's speed. In addition, there are situations for which it is generally impossible to determine the speed of an object without taking into account the transverse Doppler effect. The authors analyze the fundamental possibilities of improving the functioning of radar stations that simultaneously use both types of Doppler effects – longitudinal and transverse ones – making it possible to determine the total speed of the observed object in any situations. The authors have analyzed the longitudinal and transverse Doppler effects for the case of a moving emitting object, derived expressions for the Doppler shift and expressions for the beat frequency in the case of an active radar station for both types of Doppler effects, which make it possible to obtain the value of the object's speed in any situations. Variants of determining the total speed of a moving object have been proposed, accounting the determination of its radial and tangential components. Idealized situations in which only one of the Doppler effects appeared have been considered.

Doppler-Pulsatility Index

PEDIATRICS ◽  
1983 ◽  
Vol 71 (2) ◽  
pp. 298-299
Author(s):  
DANIEL G. BATTON ◽  
JONATHAN HELLMANN ◽  
M. JEFFREY MAISELS
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Doppler Effect ◽  
Pulsatility Index ◽  
Blood Velocity ◽  
Cerebral Blood Velocity ◽  
Considerable Controversy ◽  
The Doppler Effect ◽  
Cerebral Vascular Resistance

To the Editor.— The determination of cerebral blood velocity in the newborn infant using transfontanel Doppler ultrasound has been discussed in detail in two recent commentaries.1,2 Whereas the use of the Doppler effect to determine blood velocity is well accepted, it is apparent that considerable controversy exists regarding the ability of this technique to measure cerebral blood flow in the neonate.1,2 In particular, the hemodynamic significance of the pulsatility index (PI) remains unclear. It has been suggested that the PI reflects cerebral vascular resistance based on the assumption that, as resistance is altered, primarily diastolic, and not systolic, blood velocity will change.

scholarly journals New Equation for Predicting Pipe Friction Coefficients Using the Statistical Based Entropy Concepts

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 611
Author(s):  
Yeon-Woong Choe ◽  
Sang-Bo Sim ◽  
Yeon-Moon Choo
Keyword(s):  
Friction Coefficient ◽  
Accurate Determination ◽  
Mean Velocity ◽  
Friction Coefficients ◽  
Flow Discharge ◽  
Comparison Results ◽  
Flow Loss ◽  
Key Variables ◽  
New Equation

In general, this new equation is significant for designing and operating a pipeline to predict flow discharge. In order to predict the flow discharge, accurate determination of the flow loss due to pipe friction is very important. However, existing pipe friction coefficient equations have difficulties in obtaining key variables or those only applicable to pipes with specific conditions. Thus, this study develops a new equation for predicting pipe friction coefficients using statistically based entropy concepts, which are currently being used in various fields. The parameters in the proposed equation can be easily obtained and are easy to estimate. Existing formulas for calculating pipe friction coefficient requires the friction head loss and Reynolds number. Unlike existing formulas, the proposed equation only requires pipe specifications, entropy value and average velocity. The developed equation can predict the friction coefficient by using the well-known entropy, the mean velocity and the pipe specifications. The comparison results with the Nikuradse’s experimental data show that the R2 and RMSE values were 0.998 and 0.000366 in smooth pipe, and 0.979 to 0.994 or 0.000399 to 0.000436 in rough pipe, and the discrepancy ratio analysis results show that the accuracy of both results in smooth and rough pipes is very close to zero. The proposed equation will enable the easier estimation of flow rates.

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