scholarly journals Dynamic process and flow-rate regulation mechanism of particle inertial focusing in an asymmetric ally curved microchannel

2015 ◽  
Vol 64 (18) ◽  
pp. 184703
Author(s):  
Tang Wen-Lai ◽  
Xiang Nan ◽  
Zhang Xin-Jie ◽  
Huang Di ◽  
Ni Zhong-Hua
Keyword(s):  
Flow Rate ◽  
Dynamic Process ◽  
Regulation Mechanism ◽  
Inertial Focusing ◽  
Rate Regulation

A Cephalopod-Inspired Soft-Robotic Siphon for Thrust Vectoring and Flow Rate Regulation

Soft Robotics ◽  
2020 ◽  
Author(s):  
Runzhi Zhang ◽  
Zhong Shen ◽  
Hua Zhong ◽  
Jiyong Tan ◽  
Yong Hu ◽  
...  
Keyword(s):  
Flow Rate ◽  
Thrust Vectoring ◽  
Rate Regulation

The impact of capillary dilation on the distribution of red blood cells in artificial networks

2015 ◽  
Vol 308 (7) ◽  
pp. H733-H742 ◽  
Author(s):  
Franca Schmid ◽  
Johannes Reichold ◽  
Bruno Weber ◽  
Patrick Jenny
Keyword(s):  
Flow Rate ◽  
Self Regulation ◽  
Blood Flow Rate ◽  
Regulation Mechanism ◽  
Parent Vessel ◽  
Capillary Networks ◽  
Dilation Factor ◽  
Network Simulations ◽  
The Impact ◽  
Capillary Dilation

Recent studies suggest that pericytes around capillaries are contractile and able to alter the diameter of capillaries. To investigate the effects of capillary dilation on network dynamics, we performed simulations in artificial capillary networks of different sizes and complexities. The unequal partition of hematocrit at diverging bifurcations was modeled by assuming that each red blood cell (RBC) enters the branch with the faster instantaneous flow. Network simulations with and without RBCs were performed to investigate the effect of local dilations. The results showed that the increase in flow rate due to capillary dilation was less when the effects of RBCs are included. For bifurcations with sufficient RBCs in the parent vessel and nearly equal flows in the branches, the flow rate in the dilated branch did not increase. Instead, a self-regulation of flow was observed due to accumulation of RBCs in the dilated capillary. A parametric study was performed to examine the dependence on initial capillary diameter, dilation factor, and tube hematocrit. Furthermore, the conditions needed for an efficient self-regulation mechanism are discussed. The results support the hypothesis that RBCs play a significant role for the fluid dynamics in capillary networks and that it is crucial to consider the blood flow rate and the distribution of RBCs to understand the supply of oxygen in the vasculature. Furthermore, our results suggest that capillary dilation/constriction offers the potential of being an efficient mechanism to alter the distribution of RBCs locally and hence could be important for the local regulation of oxygen delivery.

scholarly journals Analyzing the Energy Efficiency of Fan Systems by Using the Dimensional Analysis (DA) Method

Symmetry ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 537 ◽  
Author(s):  
Gencho Popov ◽  
Kliment Klimentov ◽  
Boris Kostov ◽  
Reneta Dimitrova
Keyword(s):  
Energy Efficiency ◽  
Dimensional Analysis ◽  
Flow Rate ◽  
Energy Use ◽  
Specific Energy Consumption ◽  
Effective Energy ◽  
Frequency Method ◽  
Rate Regulation ◽  
Pipe System ◽  
The Impact

This work represents a method for investigating the energy efficiency of fan systems used to transport fluids. Applying the methods of dimensional analysis (DA) enables establishing five dimensionless complexes ( π criteria), including some basic parameters having impacts on the consumed energy used for the transportation of a unit quantity of air. The proposed criterion π 1 includes the specific energy consumption e v (specific fan power SFP), and is used for the quantitative evaluation of the energy effectiveness of the fluid transportation. This criterion also includes the main geometric size of the pipe system (network) and the gas properties. The criterion π 3 indicates the impact of the applied method of flow rate regulation on the effective energy use of fan systems. This criterion includes parameters characterizing the selected method of flow rate regulation: speed ( n ) for using the frequency method and the referred length ( L T P ) of the pipe system for using the throttle method. The established (proposed) dimensionless parameters are used to study a concrete fan system. The obtained results concerning the evaluation of the impact of the two most used methods of flow rate regulation (frequency and throttle), as well as the density variation as a result of the temperature change, on the effective energy use are graphically presented: π 1 = f ( π 3 ) .

A New Shunt System with Non-Invasive Flow Rate Regulation and Pressure Measurement

Hydrocephalus ◽  
1991 ◽  
pp. 422-431 ◽  
Author(s):  
Takuo Hashimoto ◽  
Norio Nakamura ◽  
Toshinori Kanki ◽  
Hideaki Shimazu ◽  
Ken-ichi Yamakoshi ◽  
...  
Keyword(s):  
Flow Rate ◽  
Pressure Measurement ◽  
Shunt System ◽  
Rate Regulation ◽  
Non Invasive

Anaerobic Capacity in Biathletes Depending on the Type of Autonomic Heart Rate Regulation

2020 ◽  
pp. 368-377
Author(s):  
Fedor B. Litvin ◽  
◽  
Tat’yana M. Bruk ◽  
Pavel A. Terekhov ◽  
Natal’ya V. Osipova
Keyword(s):  
Heart Rate ◽  
Power Output ◽  
Maximum Speed ◽  
Regulation Mechanism ◽  
Relative Power ◽  
Work Output ◽  
Total Work ◽  
Absolute Power ◽  
Rate Regulation ◽  
Heart Rate Regulation

Successful work of biathletes on the track and at the shooting range largely depends on the typological features of the autonomic regulation of heart rate. We examined 46 biathletes aged 18–25 years. The types of autonomic heart rate regulation were determined according to the generally accepted method using Varikard 2.51 equipment. Sport-specific performance was measured on the Ergomedic 894E Peak Bike ergometer (Monark Exercise, Sweden). Personified types of autonomic heart rate regulation were combined into two groups: with the dominance of the central regulation mechanism (CRM, 45 % of subjects) and of the autonomic regulation mechanism (ARM, 55 % of subjects). The 6-second test for assessing speed abilities revealed statistically significant (p < 0.05) differences: biathletes with CRM were faster, their peak power output was higher and their time to reach maximum speed was shorter compared to biathletes with ARM. As to the strength abilities, subjects with CRM were superior (p < 0.05) to their colleagues in terms of speed and relative power output; their power gradient was greater, and their time to reach maximum speed was shorter (p < 0.05). During the 15-second test, biathletes with ARM showed a statistically significant (p < 0.05) increase in total work output, absolute power output, and endurance coefficient compared to the subjects with CRM. When switching to the 45-second mode, biathletes with ARM retained their advantages (p < 0.05) in terms of total work output, absolute power output, and speed endurance. At the same time, their relative power output was lower compared to that of athletes with CRM. Thus, with the shortest possible anaerobic mode, the efficiency is higher in biathletes with dominant CRM, while at longer modes, in biathletes with ARM predominance.

Research Progress on Variable-Rate Spraying Technology in Orchards

2020 ◽  
Vol 36 (6) ◽  
pp. 927-942
Author(s):  
Chenchen Gu ◽  
Xiu Wang ◽  
Xiaole Wang ◽  
Fuzeng Yang ◽  
Changyuan Zhai
Keyword(s):  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Future Research ◽  
Variable Rate ◽  
Rate Regulation ◽  
Advantages And Disadvantages ◽  
Air Supply ◽  
Canopy Volume ◽  
Variable Rate Spraying

HighlightsReview the research status of variable-rate spraying technology and point out the direction for the future researchDiscussed the advantages and disadvantages of different techniques to detect canopy volume and canopy biomassThe air speed and volume adjustment need to be controlled based on the canopy detection systemAbstract. Variable-rate pesticide application in orchards aims to solve the problems of low pesticide utilization rates and serious environmental pollution in traditional pesticide applications. In this article, we have reviewed the research status of the technology to point out the direction for future research. Orchard tree canopy volume detection, biomass detection, and variable-rate spraying control methods were systematically summarized and analyzed. The advantages and disadvantages of different sensing techniques for detecting canopy volume and canopy biomass have been discussed. Canopy volume is mainly detected by ultrasonic sensors and light detection and ranging (LiDAR) sensors. Canopy biomass detection can be realized by manual, ultrasonic sensors, LiDAR sensors, and other sensors. Variable-rate spraying control is in two parts: liquid flow rate regulation and air supply rate regulation. In order to determine the volume of the liquid variable-spray, the variable air supply of air-assisted sprayer has been proven to be important. Liquid flow regulation can be achieved by pipeline pressure control and nozzle flow rate control together with a series of algorithms. The direction of air supply is easy to determine, but the air speed and volume adjustment need to be controlled based on the canopy detection system. Finally, future research on variable-rate spraying technology should focus on: 1) the application of advanced sensing technology for accurate and real-time measurement of canopy volume and biomass, 2) accurate control algorithms for liquid flow rate regulation and methods for airflow regulation, and 3) design of variable-rate sprayers with both liquid and air regulations, and the establishment of different types of variable-rate models for different sprayer types. Keywords: Air supply rate regulation, Canopy biomass detection, Canopy volume detection, Liquid flow rate regulation, Orchard, Variable-rate spraying.

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