Measurement method of spherical large curvature radius

2012 ◽  
Author(s):  
Youhan Guo ◽  
Shunxin Liu ◽  
Ye Yang
Keyword(s):  
Measurement Method ◽  
Curvature Radius ◽  
Large Curvature

Large Curvature Effect on Pulsatile Entrance Flow in a Curved Tube: Model Experiment Simulating Blood Flow in an Aortic Arch

1996 ◽  
Vol 118 (2) ◽  
pp. 180-186 ◽  
Author(s):  
T. Naruse ◽  
K. Tanishita
Keyword(s):  
Blood Flow ◽  
Aortic Arch ◽  
Maximum Velocity ◽  
Curvature Radius ◽  
Wall Region ◽  
Dean Number ◽  
Large Curvature ◽  
Curved Tube ◽  
Wall Shear ◽  
Entrance Flow

We measured the velocity profiles of pulsatile entrance flow in a strongly curved tube using a laser-Doppler anemometer in order to simulate blood flow in the aortic arch under various conditions, i.e., a ratio of tube to curvature radius of 1/3, Womersley parameters of 12 and 18, and peak Dean number up to 1200. Axial isovelocity contours of the cross-section showed the potential vortex to be near the entrance, and with the maximum velocity there being skewed towards the inner wall; thereafter shifting towards the outer wall. During the deceleration phase, reverse axial flow occurred near the inner wall, and a region of this flow extended downstream. The large curvature contributes to the enhancement of the secondary flow and flow reversal, which elevates the wall-shear stress oscillations. The location of elevated wall-shear oscillations corresponds to the vessel wall region where atherosclerotic formation frequently occurs; thereby indicating that both the large curvature and pulsatility play key roles in formation of localized atherosclerotic lesions.

Precision Design and Analysis of Large Curvature Radius Measurement System

2017 ◽  
Vol 54 (6) ◽  
pp. 061205
Author(s):  
魏凤龙 Wei Fenglong ◽  
田 伟 Tian Wei ◽  
彭石军 Peng Shijun
Keyword(s):  
Measurement System ◽  
Curvature Radius ◽  
Large Curvature ◽  
Precision Design

Development of a Contactless Measurement Method Using an LED-Optical Displacement Sensor for Vibration Stress of Piping Systems

2015 ◽  
Author(s):  
Akira Maekawa ◽  
Takashi Tsuji ◽  
Tsuneo Takahashi
Keyword(s):  
Measurement Method ◽  
Previous Method ◽  
Measuring System ◽  
Displacement Sensor ◽  
Contactless Measurement ◽  
Curvature Radius ◽  
Piping System ◽  
Optical Displacement ◽  
Piping Systems ◽  
Vibration Stress

The present paper proposes an efficient contactless measurement method for vibration stress of piping systems, by which the measurement tasks are performed within an extremely short time and the measured stress can be evaluated immediately after the measurement. The proposed method includes two processes, in which the bending shape of a pipe induced by vibration response is identified by a transmission-type optical displacement sensor and the vibration stress is calculated based on beam theory using the curvature radius estimated by approximating the bending shape. The proposed method uses only one LED-optical sensor to measure the vibration stress though multiple sensors must be used in the previous method developed by the authors. Therefore, the measuring system could be reduced in size and a light-weight and portable measurement instrument was developed. The measurement accuracy and reliability of the new method were verified by the vibration experiment using a mock-up piping system.

A Magnetic Spectrometer for a Scanning Transmission Electron Microscope

1974 ◽  
Vol 32 ◽  
pp. 436-437
Author(s):  
A. Kosiara ◽  
J. W. Wiggins ◽  
M. Beer
Keyword(s):  
Scanning Transmission Electron Microscope ◽  
Magnetic Spectrometer ◽  
Fringe Field ◽  
Curvature Radius ◽  
Magnetic Pole ◽  
Quadrupole Field ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Under Construction ◽  
Image Position

A magnetic spectrometer to be attached to the Johns Hopkins S. T. E. M. is under construction. Its main purpose will be to investigate electron interactions with biological molecules in the energy range of 40 KeV to 100 KeV. The spectrometer is of the type described by Kerwin and by Crewe Its magnetic pole boundary is given by the equationwhere R is the electron curvature radius. In our case, R = 15 cm. The electron beam will be deflected by an angle of 90°. The distance between the electron source and the pole boundary will be 30 cm. A linear fringe field will be generated by a quadrupole field arrangement. This is accomplished by a grounded mirror plate and a 45° taper of the magnetic pole.

Analysis of significant measures for thermal conductivity

2020 ◽  
pp. 35-42
Author(s):  
Yuri P. Zarichnyak ◽  
Vyacheslav P. Khodunkov
Keyword(s):  
Thermal Conductivity ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Heat Flux Density ◽  
Measurement Method ◽  
Conductivity Measurement ◽  
Surface Heat ◽  
Measuring Instrument ◽  
New Class ◽  
Achievable Accuracy

The analysis of a new class of measuring instrument for heat quantities based on the use of multi-valued measures of heat conductivity of solids. For example, measuring thermal conductivity of solids shown the fallacy of the proposed approach and the illegality of the use of the principle of ambiguity to intensive thermal quantities. As a proof of the error of the approach, the relations for the thermal conductivities of the component elements of a heat pump that implements a multi-valued measure of thermal conductivity are given, and the limiting cases are considered. In two ways, it is established that the thermal conductivity of the specified measure does not depend on the value of the supplied heat flow. It is shown that the declared accuracy of the thermal conductivity measurement method does not correspond to the actual achievable accuracy values and the standard for the unit of surface heat flux density GET 172-2016. The estimation of the currently achievable accuracy of measuring the thermal conductivity of solids is given. The directions of further research and possible solutions to the problem are given.

Acoustic Distance Measurement Method Using 2ch Microphones Measurable from 0m Based on Phase Interference and Removal of DC Component

2015 ◽  
Vol 135 (11) ◽  
pp. 1349-1350
Author(s):  
Kazuhiro Suzuki ◽  
Noboru Nakasako ◽  
Masato Nakayama ◽  
Toshihiro Shinohara ◽  
Tetsuji Uebo
Keyword(s):  
Measurement Method ◽  
Distance Measurement ◽  
Phase Interference ◽  
Dc Component
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