scholarly journals A Fast Bubble Detection Method in Microtubes Based on Pulsed Ultrasound

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1402
Author(s):  
Yiqing Li ◽  
Junwu Wu ◽  
Leijie Fu ◽  
Jinju Wang
Keyword(s):  
Detection Method ◽  
Measurement Data ◽  
Liquid Volume ◽  
Pulsed Ultrasound ◽  
Timely Manner ◽  
Device Structure ◽  
Two Phase ◽  
Phase Theory ◽  
Bubble Detection ◽  
Working Principle

In the process of biological microfluidic manipulation, the bubbles generated in the tube will seriously reduce the gauging accuracy. This paper introduces an improving method that can estimate the size of microbubbles in real time. Hence, the measurement data of the liquid volume can be modified according to this method. A microbubble detector based on the pulsed-ultrasound method was studied, including the device structure and the working principle. The assessment formula of the microbubbles in the tube was derived from the simulation results, which adopted the two-phase theory. The digital image processing method was applied to fulfill the microbubble calibration. This detection method was applied to measure the microbubbles in the tube and to modify the flow volume in a timely manner. The results of the experiments showed that this method is effective at improving the microflow gauging accuracy.

Two-phase flow bubble detection method applied to natural circulation system using fuzzy image processing

2018 ◽  
Vol 335 ◽  
pp. 255-264 ◽  
Author(s):  
R.C. Bueno ◽  
P.H.F. Masotti ◽  
J.F. Justo ◽  
D.A. Andrade ◽  
M.S. Rocha ◽  
...  
Keyword(s):  
Image Processing ◽  
Two Phase Flow ◽  
Detection Method ◽  
Natural Circulation ◽  
Circulation System ◽  
Phase Flow ◽  
Two Phase ◽  
Bubble Detection ◽  
Fuzzy Image

Determination of specific interfacial areas in swirled two-phase flow

1983 ◽  
Vol 48 (3) ◽  
pp. 842-853
Author(s):  
Kurt Winkler ◽  
František Kaštánek ◽  
Jan Kratochvíl
Keyword(s):  
Interfacial Area ◽  
Liquid Volume ◽  
Upward Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Mist Flow ◽  
Interfacial Areas ◽  
Correlation Parameters ◽  
Flow Components

Specific gas-liquid interfacial area in flow tubes 70 mm in diameter of the length 725 and 1 450 mm resp. containing various swirl bodies were measured for concurrent upward flow in the ranges of average gas (air) velocities 11 to 35 ms-1 and liquid flow rates 13 to 80 m3 m-2 h-1 using the method of CO2 absorption into NaOH solutions. Two different flow regimes were observed: slug flow swirled annular-mist flow. In the latter case the determination was carried out separately for the film and spray flow components, respectively. The obtained specific areas range between 500 to 20 000 m3 m-2. Correlation parameters are energy dissipation criteria, related to the geometrical reactor volume and to the static liquid volume in the reactor.

scholarly journals A Two-Phase Fashion Apparel Detection Method Based on YOLOv4

2021 ◽  
Vol 11 (9) ◽  
pp. 3782
Author(s):  
Chu-Hui Lee ◽  
Chen-Wei Lin
Keyword(s):  
Object Detection ◽  
Transfer Learning ◽  
Detection Method ◽  
Phase Transfer ◽  
Recognition Task ◽  
Phase Detection ◽  
Target Domain ◽  
Two Phase ◽  
Detection Technology ◽  
Fashion Apparel

Object detection is one of the important technologies in the field of computer vision. In the area of fashion apparel, object detection technology has various applications, such as apparel recognition, apparel detection, fashion recommendation, and online search. The recognition task is difficult for a computer because fashion apparel images have different characteristics of clothing appearance and material. Currently, fast and accurate object detection is the most important goal in this field. In this study, we proposed a two-phase fashion apparel detection method named YOLOv4-TPD (YOLOv4 Two-Phase Detection), based on the YOLOv4 algorithm, to address this challenge. The target categories for model detection were divided into the jacket, top, pants, skirt, and bag. According to the definition of inductive transfer learning, the purpose was to transfer the knowledge from the source domain to the target domain that could improve the effect of tasks in the target domain. Therefore, we used the two-phase training method to implement the transfer learning. Finally, the experimental results showed that the mAP of our model was better than the original YOLOv4 model through the two-phase transfer learning. The proposed model has multiple potential applications, such as an automatic labeling system, style retrieval, and similarity detection.

scholarly journals Physics-Based TCAD Simulation and Calibration of 600 V GaN/AlGaN/GaN Device Characteristics and Analysis of Interface Traps

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 751
Author(s):  
Yu-Lin Song ◽  
Manoj Kumar Reddy ◽  
Luh-Maan Chang ◽  
Gene Sheu
Keyword(s):  
Conduction Band ◽  
Computer Aided Design ◽  
Measurement Data ◽  
High Electron Mobility Transistor ◽  
High Electron ◽  
Device Structure ◽  
Gan Hemt ◽  
Fixed Charges ◽  
Vertical Electric Field ◽  
Aided Design

This study proposes an analysis of the physics-based TCAD (Technology Computer-Aided Design) simulation procedure for GaN/AlGaN/GaN HEMT (High Electron Mobility Transistor) device structures grown on Si (111) substrate which is calibrated against measurement data. The presence of traps and activation energies in the device structure will impact the performance of a device, the source of traps and position of traps in the device remains as a complex exercise until today. The key parameters for the precise tuning of threshold voltage (Vth) in GaN transistors are the control of the positive fixed charges −5 × 1012 cm−2, donor-like traps −3 × 1013 cm−2 at the nitride/GaN interfaces, the energy of the donor-like traps 1.42 eV below the conduction band and the acceptor traps activation energy in the AlGaN layer and buffer regions with 0.59 eV below the conduction band. Hence in this paper, the sensitivity of the trap mechanisms in GaN/AlGaN/GaN HEMT transistors, understanding the absolute vertical electric field distribution, electron density and the physical characteristics of the device has been investigated and the results are in good agreement with GaN experimental data.

A Novel Method for Perception and Map Construction of Environment Information Based on Laser Range Finder

2013 ◽  
Vol 347-350 ◽  
pp. 307-311
Author(s):  
Wen Jie Zhu ◽  
Guang Long Wang ◽  
Feng Qi Gao ◽  
Zhong Tao Qiao ◽  
Ji Chen Li
Keyword(s):  
Communication Protocol ◽  
Measurement Data ◽  
Laser Range Finder ◽  
Visualization Method ◽  
Range Finder ◽  
Laser Range ◽  
Range Finding ◽  
Map Construction ◽  
Working Principle ◽  
Novel Method

A method for perception and map construction of the unknown environmental information is described in this paper by analyzing and processing the data measured by laser range finder (LRF). The structure of the laser range finder, the structure of its returned measurement data, its working principle, and communication protocol are presented. The physical meaning of the data are studied and illustrated as well as its representation methods. The corresponding algorithm routine and the GUI interface program are introduced. Experiments are conducted to verify the range finding accuracy of the sensor and the data visualization method is also introduced. Results indicate that the proposed method is sufficiently valid and can satisfy the desired requirements.

scholarly journals Collisions of Two-Phase Liquid Droplets in a Heated Gas Medium

Entropy ◽  
2021 ◽  
Vol 23 (11) ◽  
pp. 1476
Author(s):  
Pavel Tkachenko ◽  
Nikita Shlegel ◽  
Pavel Strizhak
Keyword(s):  
Volume Fraction ◽  
Industrial Applications ◽  
Droplet Breakup ◽  
Liquid Volume ◽  
Liquid Droplets ◽  
Vapor Bubbles ◽  
Two Phase ◽  
Relative Volume Fraction ◽  
Phase Liquid ◽  
Gas Medium

The paper presents the experimental research findings for the integral characteristics of processes developing when two-phase liquid droplets collide in a heated gas medium. The experiments were conducted in a closed heat exchange chamber space filled with air. The gas medium was heated to 400–500 °C by an induction system. In the experiments, the size of initial droplets, their velocities and impact angles were varied in the ranges typical of industrial applications. The main varied parameter was the percentage of vapor (volume of bubbles) in the droplet (up to 90% of the liquid volume). The droplet collision regimes (coalescence, bounce, breakup, disruption), size and number of secondary fragments, as well as the relative volume fraction of vapor bubbles in them were recorded. Differences in the collision regimes and in the distribution of secondary fragments by size were identified. The areas of liquid surface before and after the initial droplet breakup were determined. Conditions were outlined in which vapor bubbles had a significant and, on the contrary, fairly weak effect on the interaction regimes of two-phase droplets.

Aerobic phenanthrene biodegradation in a two-phase partitioning bioreactor

2005 ◽  
Vol 52 (8) ◽  
pp. 265-271 ◽  
Author(s):  
R. Muñoz ◽  
C. Rolvering ◽  
B. Guieysse ◽  
B. Mattiasson
Keyword(s):  
Silicone Oil ◽  
Liquid Volume ◽  
Agitation Rate ◽  
Two Phase ◽  
Phase Partitioning ◽  
Partitioning Bioreactor ◽  
Photosynthetic Oxygenation ◽  
Mechanical Aeration ◽  
Phenanthrene Biodegradation ◽  
Two Phase Partitioning Bioreactor

The aerobic degradation of phenanthrene by a Pseudomonas migulae strain under classical mechanical aeration and under photosynthetic oxygenation (using a Chlorella sorokiniana strain) in a two-phase partitioning bioreactor (TPPB) constructed with silicone oil as organic phase was investigated. When traditional mechanical aeration was used, an increase in the aeration and/or in the agitation rate enhanced phenanthrene biodegradation. Thus, phenanthrene removal rates (based on the total liquid volume of cultivation) ranged from 22±1 to 36±2mg/lh at 100rpm and 1vvm and 400rpm and 3vvm, respectively. On the other hand, during phenanthrene biodegradation using the algal-bacterial microcosm a maximum rate of 8.1±1.2mg/lh at 200rpm and 8000 lux of illuminance was achieved.

Image Reconstruction Algorithm Based On PCA and WNN for ECT

2013 ◽  
Vol 5 (4) ◽  
pp. 33-40
Author(s):  
Lifeng Zhang
Keyword(s):  
Image Reconstruction ◽  
Adaptive Learning ◽  
Transfer Functions ◽  
Measurement Data ◽  
Principal Component ◽  
Reconstruction Algorithm ◽  
Simulation Software ◽  
Iteration Algorithm ◽  
Two Phase ◽  
Image Reconstruction Algorithm

Electrical capacitance tomography (ECT) technique is a new technique for two-phase flow measurement. ECT is a complex nonlinear problem. To solve the ill-posed image reconstruction problem, image reconstruction algorithm based on wavelet neural networks (WNN) was presented. The principal component analysis (PCA) method was used to reduce the dimension of the input vectors. The transfer functions of the neurons in the WNN were wavelet base functions which were determined by retract and translation factors. The input measurement data were obtained using the ECT simulation software developed by the author. BP algorithm was used to train the WNN, and self-adaptive learning rate and momentum coefficient were also used to accelerate the learning speed. Experimental results showed the image quality has been improved markedly, compared with the typical linear back projection (LBP) algorithm and Landweber iteration algorithm.

scholarly journals Research and Application of Mathematical Model of Transmission Grating Signal Lissajous Figure

2018 ◽  
Vol 232 ◽  
pp. 03046
Author(s):  
Luqing Hu ◽  
Xianqing Lei ◽  
Xiaoyi Wang ◽  
Yadong Zhang ◽  
Xiaolin Zuo
Keyword(s):  
Mathematical Model ◽  
Measurement System ◽  
Electrical Signal ◽  
Two Phase ◽  
Lissajous Figure ◽  
Transmission Grating ◽  
Straight Line ◽  
Voltage Signal ◽  
Working Principle ◽  
Grating Pair

In this paper, the working principle of the grating measurement system is combined with the Fourier analysis method of Moiré fringe to establish the mathematical model of the grating signal Lissajous figure to know the quality of the grating signal intuitively. The Mathematica numerical analysis software is used to obtain the graphics of the model, and the correctness of the relationship between the parameters of the grating measurement system and the Lissajous figure equation of the grating signal is verified. The influence of the grating pair angle α on the output voltage signal and Lissajous figure of the grating measurement system is studied. The results show that the intensity of the two-phase output electrical signal decreases gradually with the increase of the deviation of the angle α of the grating pair, but the equal-amplitude of the two-phase output electrical signal does not change; Meanwhile, the shape of the grating signal Lissajous figure gradually changes from the ideal circle to the non-ideal ellipse, until a straight line with a strip slope of 135° is formed.

Heat Transport Characteristics in Closed Loop Oscillating Heat Pipes

2005 ◽  
Author(s):  
Shuangfeng Wang ◽  
Shigefumi Nishio
Keyword(s):  
Heat Pipe ◽  
Heat Transport ◽  
Closed Loop ◽  
Flow Behavior ◽  
Working Fluid ◽  
Liquid Volume ◽  
High Heat Flux ◽  
Two Phase ◽  
Working Fluids ◽  
Inner Diameter

Heat transport rates of micro scale SEMOS (Self-Exciting Mode Oscillating) heat pipe with inner diameter of 1.5mm, 1.2mm and 0.9mm, were investigated by using R141b, ethanol and water as working fluids. The effects of inner diameter, liquid volume faction, and material properties of the working fluids are examined. It shows that the smaller the inner diameter, the higher the thermal transport density is. For removing high heat flux, the water is the most promising working fluid as it has the largest critical heat transfer rate and the widest operating range among the three kinds of working fluids. A one-dimensional numerical simulation is carried out to describe the heat transport characteristics and the two-phase flow behavior in the closed loop SEMOS heat pipe. The numerical prediction agrees with the experimental results fairly well, when the input heat through was not very high and the flow pattern was slug flow.   This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.

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