Experimental study on skin surface character utilizing laser Doppler effect

2002 ◽  
Author(s):  
Yong Ni ◽  
Kexin Xu ◽  
Xiaofang Zhang ◽  
Chengzhi Jiang
Keyword(s):  
Experimental Study ◽  
Doppler Effect ◽  
Skin Surface ◽  
Laser Doppler ◽  
Surface Character

Skin-skin contact: The normal-force dependence of the coefficient of friction between a bare finger and artificial skin changes randomly

2021 ◽  
Author(s):  
Koki Inoue ◽  
Shogo Okamoto ◽  
Yasuhiro Akiyama ◽  
Yoji Yamada
Keyword(s):  
Experimental Study ◽  
Coefficient Of Friction ◽  
Normal Force ◽  
Skin Surface ◽  
Artificial Skin ◽  
Skin Changes ◽  
Root Cause ◽  
Skin Contact ◽  
The Coefficient Of Friction ◽  
Frictional Forces

Abstract This study investigates the dependence of the coefficients of friction on the normal force produced by sliding a bare finger over different artificial skins with seven levels of hardness. The coefficient of friction was modeled as a power function of the normal force. An experimental study that involved sliding a finger over artificial skin surfaces was carried out under two conditions: the fingertip being wiped by a dry cloth or a cloth soaked in ethanol. Although the exponential term was assumed to be nearly constant for identical tribological conditions, we observed that the exponent varied randomly and could be negative, zero, or positive. This probabilistic behavior has not been explicitly analyzed in previous studies on human fingertips. The probability density function of the exponent depended on the moisture content of the finger. The exponent was either nearly zero or positive when the finger sliding on the skin surface was wiped with an alcohol-soaked cloth and dried. These findings play an important role in analyzing the frictional forces produced during skin–skin contact in terms of determining the root cause behind the random variations in the dependence of the coefficient of friction on the normal force.

Complexity Analysis of Beat-to-Beat Skin-Surface Laser-Doppler Flowmetry Signals in Stroke Patients

2015 ◽  
Vol 22 (5) ◽  
pp. 370-377 ◽  
Author(s):  
Chao-Tsung Chen ◽  
Hsin Hsiu ◽  
Jin-Shiang Fan ◽  
Fong-Cheng Lin ◽  
Yen-Ting Liu
Keyword(s):  
Laser Doppler Flowmetry ◽  
Complexity Analysis ◽  
Skin Surface ◽  
Laser Doppler ◽  
Stroke Patients ◽  
Doppler Flowmetry ◽  
Surface Laser

PULSE-WAVEFORM AND LASER-DOPPLER INDICES FOR IDENTIFYING COLORECTAL-CANCER PATIENTS

2020 ◽  
pp. 2150005
Author(s):  
Chao-Tsung Chen ◽  
Chin-Tsing Ting ◽  
Chun-Yeh Chen ◽  
Zong-Jhe Lyu ◽  
Chien-Cheng Chen ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Blood Flow ◽  
Pulse Wave ◽  
Skin Surface ◽  
Laser Doppler ◽  
Waveform Analysis ◽  
Arterial Pulse ◽  
Doppler Flowmetry ◽  
Control Subjects ◽  
Arterial Pulse Wave

This study aimed to determine the effectiveness of using noninvasive arterial pulse-wave and laser-Doppler flowmetry (LDF) measurements to discriminate between colorectal-cancer (CC) patients and healthy control subjects. Radial-artery blood pressure waveform (BPW), finger photoplethysmography (PPG), and skin-surface LDF signals were measured noninvasively in 12 CC patients and 25 control subjects. Beat-to-beat, spectral, and variability analyses were applied to 20-minute-long recorded signals. Significant intergroup differences were found. In BPW, [Formula: see text]–[Formula: see text] amplitude indices were significantly larger while [Formula: see text]–[Formula: see text] phase-angle indices were significantly smaller in the CC patients than in the controls. The PPG and LDF variability indices were significantly larger and smaller, respectively, in CC patients. The relative energy contributions of the endothelial-, neural-, and myogenic-related frequency bands in LDF were significantly smaller in CC patients. The present findings indicate that pulse and LDF waveform analysis can be used to evaluate the arterial pulse-wave transmission condition, the responses of the blood-flow perfusion, and its regulatory activities in CC patients. There could be some similarities and differences in the present indices for different types of cancer. These findings could be utilized in the development of a rapid, noninvasive, and objective technique for evaluating the CC-induced blood-flow responses.

Measurement of Impact Loads using a Laser Doppler Velocimeter

1990 ◽  
Vol 204 (1) ◽  
pp. 1-8 ◽  
Author(s):  
R S Birch ◽  
N Jones
Keyword(s):  
Experimental Study ◽  
Measuring Transducer ◽  
Research Field ◽  
Laser Doppler ◽  
Laser Doppler Velocimeter ◽  
Impact Loads ◽  
Peak Loads ◽  
Structural Impact ◽  
The Mean ◽  
Selection Of

The design and selection of transducers is an important consideration for the measurement of impact loads. This paper examines a load-measuring transducer based on a non-contact laser Doppler principle. An experimental study assesses the deformations and velocities obtained using a laser Doppler velocimeter and compares the mean and peak loads with those recorded by an accelerometer and a load cell. The paper concludes that this device is a valuable tool in the structural impact research field.

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