scholarly journals Multistage Digital-to-Analogue Chip Based on a Weighted Flow Resistance Network for Soft Actuators

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1016
Author(s):  
Zhou Zhou ◽  
Manman Xu ◽  
Chenlin Zhu ◽  
Gonghan He ◽  
Kunpeng Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Chip ◽  
Flow Resistance ◽  
Design Method ◽  
Control Unit ◽  
Digital Signal ◽  
Technical Problems ◽  
Pressure Signal ◽  
Resistance Network ◽  
Flow Adjustment

A control chip with a multistage flow-rate regulation function based on the correlation between the flow resistance and flow rate has been developed in this article. Compared with the traditional proportional solenoid valve, this kind of flow valve based on microfluidic technology has the characteristics of being light-weight and having no electric drive. It solves such technical problems as how the current digital microfluidic chip can only adjust the flow switch, and the adjustment of the flow rate is difficult. To linearize the output signal, we propose a design method of weighted resistance. The output flow is controlled by a 4-bit binary pressure signal. According to the binary value of the 4-bit pressure signal at the input, the output can achieve 16-stage flow adjustment. Furthermore, we integrate the three-dimensional flow resistance network, multilayer structure microvalve, and parallel fluid network into a single chip by using 3D printing to obtain a modular flow control unit. This structure enables the microflow control signal to be converted from a digital signal to an analogue signal (DA conversion), and is suitable for microflow driving components, such as in microfluidic chip sampling systems and proportional mixing systems. In the future, we expect this device to even be used in the automatic control system of a miniature pneumatic soft actuator.

scholarly journals Programmable hydraulic resistor for microfluidic chips using electrogate arrays

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marie L. Salva ◽  
Yuksel Temiz ◽  
Marco Rocca ◽  
Yulieth C. Arango ◽  
Christof M. Niemeyer ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Chip ◽  
Rate Control ◽  
Flow Resistance ◽  
Smartphone Application ◽  
Microfluidic Chips ◽  
Specific Flow ◽  
Flow Rates ◽  
Peripheral Device ◽  
Flow Rate Control

AbstractFlow rates play an important role in microfluidic devices because they affect the transport of chemicals and determine where and when (bio)chemical reactions occur in these devices. Flow rates can conveniently be determined using external peripherals in active microfluidics. However, setting specific flow rates in passive microfluidics is a significant challenge because they are encoded on a design and fabrication level, leaving little freedom to users for adjusting flow rates for specific applications. Here, we present a programmable hydraulic resistor where an array of “electrogates” routes an incoming liquid through a set of resistors to modulate flow rates in microfluidic chips post-fabrication. This approach combines a battery-powered peripheral device with passive capillary-driven microfluidic chips for advanced flow rate control and measurement. We specifically show a programmable hydraulic resistor composed of 7 parallel resistors and 14 electrogates. A peripheral and smartphone application allow a user to activate selected electrogates and resistors, providing 127 (27-1) flow resistance combinations with values spanning on a 500 fold range. The electrogates feature a capillary pinning site (i.e. trench across the flow path) to stop a solution and an electrode, which can be activated in a few ms using a 3 V bias to resume flow based on electrowetting. The hydraulic resistor and microfluidic chip shown here enable flow rates from ~0.09 nL.s−1 up to ~5.66 nL.s−1 with the resistor occupying a footprint of only 15.8 mm2 on a 1 × 2 cm2 microfluidic chip fabricated in silicon. We illustrate how a programmable hydraulic resistor can be used to set flow rate conditions for laminar co-flow of 2 liquids and the enzymatic conversion of a substrate by stationary enzymes (alkaline phosphatase) downstream of the programmable hydraulic resistor.

scholarly journals Effect of Subglottic Stenosis on Vocal Fold Vibration and Voice Production Using Fluid–Structure–Acoustics Interaction Simulation

2021 ◽  
Vol 11 (3) ◽  
pp. 1221
Author(s):  
Dariush Bodaghi ◽  
Qian Xue ◽  
Xudong Zheng ◽  
Scott Thomson
Keyword(s):  
Flow Rate ◽  
Vocal Fold ◽  
Flow Resistance ◽  
Signal To Noise Ratio ◽  
Area Ratio ◽  
Subglottic Stenosis ◽  
Fluid Structure ◽  
Voice Production ◽  
Vocal Fold Vibration ◽  
Glottal Flow

An in-house 3D fluid–structure–acoustic interaction numerical solver was employed to investigate the effect of subglottic stenosis (SGS) on dynamics of glottal flow, vocal fold vibration and acoustics during voice production. The investigation focused on two SGS properties, including severity defined as the percentage of area reduction and location. The results show that SGS affects voice production only when its severity is beyond a threshold, which is at 75% for the glottal flow rate and acoustics, and at 90% for the vocal fold vibrations. Beyond the threshold, the flow rate, vocal fold vibration amplitude and vocal efficiency decrease rapidly with SGS severity, while the skewness quotient, vibration frequency, signal-to-noise ratio and vocal intensity decrease slightly, and the open quotient increases slightly. Changing the location of SGS shows no effect on the dynamics. Further analysis reveals that the effect of SGS on the dynamics is primarily due to its effect on the flow resistance in the entire airway, which is found to be related to the area ratio of glottis to SGS. Below the SGS severity of 75%, which corresponds to an area ratio of glottis to SGS of 0.1, changing the SGS severity only causes very small changes in the area ratio; therefore, its effect on the flow resistance and dynamics is very small. Beyond the SGS severity of 75%, increasing the SGS severity, leads to rapid increases of the area ratio, resulting in rapid changes in the flow resistance and dynamics.

A Design Method for Thermosyphon Solar Domestic Hot Water Systems

1987 ◽  
Vol 109 (2) ◽  
pp. 150-155 ◽  
Author(s):  
M. P. Malkin ◽  
S. A. Klein ◽  
J. A. Duffie ◽  
A. B. Copsey
Keyword(s):  
Flow Rate ◽  
Design Method ◽  
Water Systems ◽  
Hot Water ◽  
Average Flow Rate ◽  
Domestic Hot Water ◽  
Average Flow ◽  
Solar Fraction ◽  
Wide Range ◽  
Flow Circuit

A modification to the f-Chart method has been developed to predict monthly and annual performance of thermosyphon solar domestic hot water systems. Stratification in the storage tank is accounted for through use of a modified collector loss coefficient. The varying flow rate throughout the day and year in a thermosyphon system is accounted for through use of a fixed monthly “equivalent average” flow rate. The “equivalent average” flow rate is that which balances the thermosyphon buoyancy driving force with the frictional losses in the flow circuit on a monthly average basis. Comparison between the annual solar fraction predited by the modified design method and TRNSYS simulations for a wide range of thermosyphon systems shows an RMS error of 2.6 percent.

Chest wall and respiratory system mechanics in cats: effects of flow and volume

1988 ◽  
Vol 64 (6) ◽  
pp. 2636-2646 ◽  
Author(s):  
T. Kochi ◽  
S. Okubo ◽  
W. A. Zin ◽  
J. Milic-Emili
Keyword(s):  
Chest Wall ◽  
Time Constant ◽  
Flow Rate ◽  
Respiratory System ◽  
Flow Resistance ◽  
Stress Adaptation ◽  
Inspiratory Flow Rate ◽  
Intrinsic Resistance ◽  
Pressure Losses ◽  
Airway Occlusion

The effects of inspiratory flow rate and inflation volume on the resistive properties of the chest wall were investigated in six anesthetized paralyzed cats by use of the technique of rapid airway occlusion during constant flow inflation. This allowed measurement of the intrinsic resistance (Rw,min) and overall dynamic inspiratory impedance (Rw,max), which includes the additional pressure losses due to time constant inequalities within the chest wall tissues and/or stress adaptation. These results, together with our previous data pertaining to the lung (Kochi et al., J. Appl. Physiol. 64: 441–450, 1988), allowed us to determine Rmin and Rmax of the total respiratory system (rs). We observed that 1) Rw,max and Rrs,max exhibited marked frequency dependence; 2) Rw,min was independent of flow (V) and inspired volume (delta V), whereas Rrs,min increased linearly with V and decreased with increasing delta V; 3) Rw,max decreased with increasing V, whereas Rrs,max exhibited a minimum value at a flow rate substantially higher than the resting range of V; 4) both Rw,max and Rrs,max increased with increasing delta V. We conclude that during resting breathing, flow resistance of the chest wall and total respiratory system, as conventionally measured, includes a significant component reflecting time constant inequalities and/or stress adaptation phenomena.

scholarly journals Research on collaborative control of double-plunger gas prover based on EtherCAT

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2667-2687
Author(s):  
Zhipeng Xu ◽  
Feipeng Xu ◽  
Dailiang Xie
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Gas Flow ◽  
Control Unit ◽  
External Diameter ◽  
Piston Cylinder ◽  
Collaborative Control ◽  
Critical Nozzles ◽  
Parallel Mode ◽  
Working Principle

Piston prover has been widely used as a gas flow standard for its advantages of high accuracy in standard volume, flow stability and repeatability. It has also been employed as the primary gas flow standard in many countries to calibrate meters. However, it is difficult to ensure the uniformity of the inside dimension of the piston, thus the application of conventional piston provers are limited by the maximum calibration flow generated by the piston cylinder volume. In this paper, an improved piston gas prover that mainly consists of two uniform plungers was proposed. Their external diameter constitutes the flow standard. The plungers are driven by servo motor, and the high speed fieldbus EtherCAT has been introduced as the control unit. Hence the two pistons could work collaboratively and operate in three modes: single-piston mode, double-pistons parallel mode, and double-pistons reciprocating mode. Besides generating steady-flow rate, the double-plunger prover can even produce an unsteady-flow rate which could be used to research the dynamic characteristics of flow meters. The structure and working principle of the three modes were carefully introduced. Then experiments for calibrating critical nozzles were carried out, and the results show that the repeatability of the discharge coefficient could be better than 0.06%, and the pressure fluctuation during the process was less than 50 Pa.

scholarly journals Spatial distributions of airborne dust in a cows barn exposed to influence of different ventilation rates

2013 ◽  
Vol 29 (2) ◽  
pp. 373-383
Author(s):  
G. Topisirovic ◽  
D.V. Petrovic ◽  
R. Maletic
Keyword(s):  
Flow Rate ◽  
Indoor Air ◽  
Rotation Rate ◽  
Natural Ventilation ◽  
Electronic Control Unit ◽  
Air Flow ◽  
Control Unit ◽  
Dust Particles ◽  
Airborne Dust ◽  
Stability And Instability

Information on the concentration of dust particles is an important microclimate parameter that characterizes the local environmental quality of each livestock building. Increased concentration of dust particles primarily affects the indoor air quality and, consequently, the animal and workers health. Among many others, ventilation rate is a vital parameter that controls the spatial distribution of airborne dust particles in livestock buildings. This was the main motive for authors of this paper to research the influence of rotation rate of under-roof axial fans (i.e. the air flow rate) on airborne dust particles distribution crossover the barn specified for tied cows breeding. During a series of performed experiments, six different air flow rates have been maintained in the range between 0 m3?h-1 and 48000 m3?h-1. Flow rate has been controlled by special electronic control unit, which provided six different rotation rates of two under-roof fans, including the neutral regime (natural ventilation only). Measurements have been performed at four typical height levels (0,5 m; 1,0 m; 1,5 m and 2,0 m), cross-over the three lateral and four longitudinal characteristic building sections. Consequently, 48 measuring points were appropriately selected, in order to cover the indoor space in adequate way. Comparative analysis of air flow velocities and dust concentrations showed that this fan setup may give satisfactory results under adequate operational regime. Certain working regimes were recommended for use, and the third rotation rate step, generating the airflow of 37300 m3?h-1 or indoor air exchange level of approximately 25 h-1, has been found as the most suitable. Projekat Ministarstva nauke Republike Srbije, br. TR31086: Optimization of technological procedures and zoo-technical resources on farmsin purpose of milk production sustainability improvement, br. TR 31051: Improvement of biotechnological procedures as a function of rational utilizationof energy, agricultural products productivity and quality increase, br. III46009: Improvement and development new technological procedures in production ofanimal products, to achieve high quality and safe competitive products inmarket i br. OI 174011: Dynamical stability and instability of mechanical systems exposed to stochasticdisturbances

scholarly journals Hardware Implementation of FTC of Induction Machine on FPGA

2017 ◽  
Vol 20 (2) ◽  
pp. 76
Author(s):  
S. Boukadida ◽  
S. Gdaim ◽  
A. Mtibaa
Keyword(s):  
Digital Signal Processor ◽  
Fault Tolerant ◽  
Design Method ◽  
Direct Torque Control ◽  
Induction Machine ◽  
Digital Signal ◽  
Design Tool ◽  
Torque Control ◽  
Algorithm Efficiency ◽  
Comparison Results

In this paper, a new design method of Direct Torque Control using Space Vector Modulation (DTC-SVM) of an Induction Machine (IM), which is based on Fault Tolerant Control (FTC) is proposed. Due to its complexity, the FTC implemented on a microcontroller and a Digital Signal Processor (DSP) is characterized by a calculating delay. To solve this problem, an alternative digital solution is used, based on the Field Programmable Gate Array (FPGA), which is characterized by a fast processing speed. However, as an FPGAs increase in size, there is a need for improved productivity, and this includes new design flows and tools. Xilinx System Generator (XSG) is a high-level block-based design tool that offers bit and cycle accurate simulation. This tool can automatically generate the Very High-Density Logic (VHDL) code without resorting to a tough programming, without being obliged to do approximations and more we can visualize the behavior of the machine before implementation which is very important for not damage our machine. Simulation and experimental results using Hardware In the Loop (HIL) of the FTC based DTC-SVM is compared with those of the conventional DTC. The comparison results illustrate the reduction in the torque and stator flux ripples. Our purpose is to reveal our algorithm efficiency and to show the Xilinx Virtex V FPGA performances in terms of execution time. 

Research on the Vortex Mass Flow Meter of Dual Bluff Body Based on Differential Pressure Principle

2013 ◽  
Vol 401-403 ◽  
pp. 1110-1113
Author(s):  
Quan Sheng Duan ◽  
Li Cui Wang
Keyword(s):  
Lower Limit ◽  
Mass Flow ◽  
Flow Rate ◽  
Bluff Body ◽  
Differential Pressure ◽  
Low Flow ◽  
Body Structure ◽  
Measurement Sensitivity ◽  
Flow Meter ◽  
Pressure Signal

The lower limit of the existing vortex mass flow meter based on differential pressure is high. So the application of the existing vortex mass flow meter is limited in the measurement for low flow rate. This paper proposes a method using vortex mass flow meter of dual bluff body based on differential pressure principle. The differential pressure signal between the upstream and downstream can be amplified by the vortex overlap caused by the dual bluff body structure. The results of the simulation by Fluent show that this method can reduce the lower limit of measurement, and improve the measurement sensitivity effectively.

Application of Z Transform in the Design of One-Dimensional Photonic Crystal

2013 ◽  
Vol 481 ◽  
pp. 225-229
Author(s):  
Juan Zhang ◽  
Wen Peng Fu ◽  
Rong Jun Zhang
Keyword(s):  
Signal Processing ◽  
Photonic Crystal ◽  
Digital Signal Processing ◽  
Design Method ◽  
Structural Parameters ◽  
Digital Signal ◽  
One Dimensional ◽  
Dimensional Photonic Crystal ◽  
Z Domain ◽  
Optical Structure

A method of designing onedimensional photonic crystal is presented from the perspective of Z-domain and digital signal processing. The optical structure and structural parameters for the desired filtering spectrum in reflection can be directly obtained by using the design method. A design example is given in the paper to verify the method.

Sign in / Sign up

Export Citation Format

Share Document