A MEMS-Based PDMS Micropump Utilizing Electromagnetic Actuation and Planar In-Contact Check Valves

2010 ◽  
Vol 139-141 ◽  
pp. 1574-1577 ◽  
Author(s):  
Jun Hui Ni ◽  
Bei Zhi Li ◽  
Jian Guo Yang
Keyword(s):  
Flow Rate ◽  
System Integration ◽  
Low Cost ◽  
Check Valve ◽  
Driving Frequency ◽  
Reliable Operation ◽  
Electromagnetic Actuation ◽  
Functional Layer ◽  
Flow Channels ◽  
Potential Use

This paper presents a novel low-cost poly(dimethylsiloxane) (PDMS) micropump with simple planar design featuring use of compliant in-contact check valves for reliable operation and easy system integration. The micropump mainly consists of two PDMS functional layers: one through-opening layer incorporating the planar in-contact check valves, pump chamber and flow channels, and the other thin membrane layer covering the chamber with a miniature permanent magnet on top for actuation. A special clamping molding technique was used to fabricate the through-opening functional layer, with which the flap-stopper based planar check valve was manipulated to contact each other enabling the minimized leakage flow. The micropump was then characterized by investigating the dependence of pumping flow rate on the driving frequency and backpressure. Testing results exhibit that the micropump is able to produce a flow rate at least of 3.0 μL/min, and work reliably against a backpressure of 1900 Pa, demonstrating the feasibility of this micropump for potential use in various lab-on-a-chip systems.

The Influence of Passive Valve Characteristics on the Performance of a Piezo Pump

2013 ◽  
Author(s):  
Jean-Paul Henderson ◽  
Andrew Plummer ◽  
D. Nigel Johnston ◽  
Chris Bowen
Keyword(s):  
Flow Rate ◽  
Check Valve ◽  
Driving Frequency ◽  
Hydraulic Actuator ◽  
Orifice Area ◽  
Low Duty Cycle ◽  
Pump Flow Rate ◽  
Piezoelectric Stack Actuator ◽  
High Temperature Rise ◽  
Expected Increase

In this study, a piezoelectric stack actuator is used to oscillate a piston in a single cylinder pump. The pump is intended to directly supply a hydraulic actuator for motion control, and power output of about 1kW is targeted. Flow rectification is achieved by the use of passive check valves. The valve resonant frequency is found to have a significant effect on output flow. The expected increase in pump flow rate with driving frequency has been confirmed in simulation to hold true in a certain frequency range only. In addition, check valve size and therefore orifice area has to be adequate in order not to prohibitively restrict flow. Valve spring stiffness and valve mass need to be simultaneously optimized for the area of the valve to achieve the highest flow rate. Calculations indicate that there is a power limitation due to the high current demand and also a high temperature rise for a large continuously operated piezo stack. Thus the piezo pump appears more promising for smaller scale applications, and those that require intermittent power (i.e. a low duty cycle).

A PDMS Micropump for Implantable Drug Delivery Application

2013 ◽  
Vol 562-565 ◽  
pp. 680-685
Author(s):  
Jun Hui Ni ◽  
Bai Shao Zhan ◽  
Jun Li
Keyword(s):  
Drug Delivery ◽  
System Integration ◽  
Single Layer ◽  
Driving Frequency ◽  
Magnetic Actuation ◽  
Test Results ◽  
Functional Layer ◽  
Drug Delivery Application ◽  
Pump Chamber ◽  
Biomedical Systems

This paper presents an integrated magnetic PDMS micropump for implantable drug delivery application. The micropump mainly consists of two structural PDMS layers: a PDMS functional layer that incorporates microchannels, a pump chamber and two planar check valves into a single layer, allowing for simple design and easy system integration, and the other PDMS membrane layer covering the pump chamber and holding a thin electroplated permalloy piece on top for magnetic actuation. The micropump can be driven by the interaction between the ferromagnetic permalloy and an external electromagnet, providing a remote and wireless operation method. Test results demonstrate that this micropump is able to produce a maximal flow rate of 0.15 μL/min at the driving frequency of 2 Hz with a volume resolution of approximately 1 nL per stroke, promising its application in various implantable biomedical systems.

scholarly journals Microfluidic Passive Flow Regulatory Device with an Integrated Check Valve for Enhanced Flow Control

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 653 ◽  
Author(s):  
Zhang ◽  
Zhang
Keyword(s):  
Flow Control ◽  
Flow Rate ◽  
Low Cost ◽  
Flow Characteristics ◽  
Check Valve ◽  
Maximum Pressure ◽  
Channel Height ◽  
Fluidic Channel ◽  
Constant Flow Rate ◽  
Passive Flow

A passive microvalve has appealing advantages in cost-effective and miniaturized microfluidic applications. In this work, we present a passive flow regulatory device for enhanced flow control in a microfluidic environment. The device was integrated with two functional elements, including a flow regulating valve and a flow check valve. Importantly, the flow regulating valve could maintain a stable flow rate over a threshold liquid pressure, and the flow check valve enabled effective liquid on/off control, thus accurate forward flow without any backward leakage was achieved. The flow performance of the flow regulating valve was analyzed through 3D FSI (Fluid-Structure Interaction) simulation, and several key parameters (i.e., fluidic channel height and width, control channel length, and Young’s modulus) were found to influence valve flow rate directly. To examine the flow characteristics of the device, we fabricated a prototype using 3D printing and UV laser cutting technologies, and the flow rates of the prototype under varied test pressures were measured in forward and reverse modes, respectively. Experimental results showed that nearly a constant flow rate of 0.42 ± 0.02 mL s−1 was achieved in the forward mode at an inlet pressure range of 70 kPa to 130 kPa, and liquid flow was totally stopped in the reverse mode at a maximum pressure of 200 kPa. The proposed microfluidic flow regulatory device could be employed for accurate flow control in low-cost and portable Lab-on-a-Chip (LoC) applications.

scholarly journals Sensor Networks for Structures Health Monitoring: Placement, Implementations, and Challenges—A Review

Vibration ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 551-584
Author(s):  
Samir Mustapha ◽  
Ye Lu ◽  
Ching-Tai Ng ◽  
Pawel Malinowski
Keyword(s):  
Sensor Networks ◽  
Health Monitoring ◽  
Data Transmission ◽  
System Integration ◽  
Structural Integrity ◽  
Low Cost ◽  
Data Communication ◽  
Total Cost ◽  
Design And Optimization ◽  
Successful Case

The development of structural health monitoring (SHM) systems and their integration in actual structures has become a necessity as it can provide a robust and low-cost solution for monitoring the structural integrity of and the ability to predict the remaining life of structures. In this review, we aim at focusing on one of the important issues of SHM, the design, and implementation of sensor networks. Location and number of sensors, in any SHM system, are of high importance as they impact the system integration, system performance, and accuracy of assessment, as well as the total cost. Hence we are interested in shedding the light on the sensor networks as an essential component of SHM systems. The review discusses several important parameters including design and optimization of sensor networks, development of academic and commercial solutions, powering of sensors, data communication, data transmission, and analytics. Finally, we presented some successful case studies including the challenges and limitations associated with the sensor networks.

scholarly journals Applicability of Cork as Novel Modifiers to Develop Electrochemical Sensor for Caffeine Determination

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 37
Author(s):  
Mayra K. S. Monteiro ◽  
Djalma R. Da Silva ◽  
Marco A. Quiroz ◽  
Vítor J. P. Vilar ◽  
Carlos A. Martínez-Huitle ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Linear Response ◽  
High Performance ◽  
Low Cost ◽  
Pharmaceutical Formulations ◽  
Caffeine Concentration ◽  
Real Samples ◽  
Wide Range ◽  
Potential Use

This study aims to investigate the applicability of a hybrid electrochemical sensor composed of cork and graphite (Gr) for detecting caffeine in aqueous solutions. Raw cork (RAC) and regranulated cork (RGC, obtained by thermal treatment of RAC with steam at 380 °C) were tested as modifiers. The results clearly showed that the cork-graphite sensors, GrRAC and GrRGC, exhibited a linear response over a wide range of caffeine concentration (5–1000 µM), with R2 of 0.99 and 0.98, respectively. The limits of detection (LOD), estimated at 2.9 and 6.1 µM for GrRAC and GrRGC, suggest greater sensitivity and reproducibility than the unmodified conventional graphite sensor. The low-cost cork-graphite sensors were successfully applied in the determination of caffeine in soft drinks and pharmaceutical formulations, presenting well-defined current signals when analyzing real samples. When comparing electrochemical determinations and high performance liquid chromatography measurements, no significant differences were observed (mean accuracy 3.0%), highlighting the potential use of these sensors to determine caffeine in different samples.

Investigation of suction flow characteristic in the inertance hydraulic converters for efficiency improvement

2021 ◽  
pp. 095965182110248
Author(s):  
Xiaoming Chen ◽  
Yuchuan Zhu ◽  
Travis Wiens ◽  
Doug Bitner ◽  
Minghao Tai ◽  
...  
Keyword(s):  
Flow Rate ◽  
Flow Characteristic ◽  
Performance Indicator ◽  
Flow Characteristics ◽  
Check Valve ◽  
Analytical Models ◽  
Switching Frequency ◽  
Experimental Measurements ◽  
Efficiency Improvement ◽  
Suction Flow

The inertance hydraulic converter relies on fluid inertance to modulate flow or pressure and is considered to be a competitive alternative to the conventional proportional hydraulic system due to its potential advantage in efficiency. As the quantification of fluid inertance, the suction flow characteristic is the crucial performance indicator for efficiency improvement. To explore the discrepancy between the passive inertance hydraulic converter featured by the check valve and the active inertance hydraulic converter driven by an equivalent 2/3 way fast switching valve in regard to suction flow characteristics, analytical models of the inertance hydraulic converters were established in MATLAB/Simulink. The validated models of the respective suction components were incorporated in the overall analytical models and their suction flow characteristics were theoretically and experimentally discussed. The analytical predictions and experimental measurements for the current configurations indicated that the active inertance hydraulic converter yields a larger transient suction flow rate than that of the passive inertance hydraulic converter due to the difference of the respective suction components. The suction flow characteristic can be modulated using the supply pressure and duty cycle, which was confirmed by experimental measurements. In addition, the suction flow characteristics are heavily affected by the resistance of the suction flow passage and switching frequency. There is a compromise between the resistance and switching frequency for inertance hydraulic converters to achieve large suction flow rate.

scholarly journals Evaluation of a Low-Cost Commercial Actigraph and Its Potential Use in Detecting Cultural Variations in Physical Activity and Sleep

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3774
Author(s):  
Pavlos Topalidis ◽  
Cristina Florea ◽  
Esther-Sevil Eigl ◽  
Anton Kurapov ◽  
Carlos Alberto Beltran Leon ◽  
...  
Keyword(s):  
Physical Activity ◽  
Low Income ◽  
Large Scale ◽  
Low Cost ◽  
Low Income Countries ◽  
Time Data ◽  
Cultural Variations ◽  
Step Counts ◽  
Scale Step ◽  
Potential Use

The purpose of the present study was to evaluate the performance of a low-cost commercial smartwatch, the Xiaomi Mi Band (MB), in extracting physical activity and sleep-related measures and show its potential use in addressing questions that require large-scale real-time data and/or intercultural data including low-income countries. We evaluated physical activity and sleep-related measures and discussed the potential application of such devices for large-scale step and sleep data acquisition. To that end, we conducted two separate studies. In Study 1, we evaluated the performance of MB by comparing it to the GT3X (ActiGraph, wGT3X-BT), a scientific actigraph used in research, as well as subjective sleep reports. In Study 2, we distributed the MB across four countries (Austria, Germany, Cuba, and Ukraine) and investigated physical activity and sleep among these countries. The results of Study 1 indicated that MB step counts correlated highly with the scientific GT3X device, but did display biases. In addition, the MB-derived wake-up and total-sleep-times showed high agreement with subjective reports, but partly deviated from GT3X predictions. Study 2 revealed similar MB step counts across countries, but significant later wake-up and bedtimes for Ukraine than the other countries. We hope that our studies will stimulate future large-scale sensor-based physical activity and sleep research studies, including various cultures.

scholarly journals The use of solar energy for the curing of ferrogeopolymer elements in the semiarid region

2019 ◽  
Vol 276 ◽  
pp. 01031 ◽  
Author(s):  
Partogi H Simatupang ◽  
Petrus Lubalu ◽  
Herry L Sianturi ◽  
Wilhelmus Bunganaen
Keyword(s):  
Solar Energy ◽  
Low Cost ◽  
Glass Plate ◽  
Energy Resource ◽  
Semiarid Region ◽  
Collector System ◽  
Good Potential ◽  
Dry Seasons ◽  
Wire Meshes ◽  
Potential Use

Kupang City in Timor Island of Indonesia, as a semiarid area, has abundant solar energy sources. Based on climatology data of Kupang City in 2013-2015, the minimum and maximum average temperatures in Kupang City range from 19.3-34.8oC. Besides, dry seasons last for about 8 months (April-November). This abundance of solar energy is a potential energy resource for the manufacturing of environmentally friendly ferrogeopolymer elements. Based on previous research, the production of geopolymer material can be done optimally with dry curing treatment at 60-80oC for less than 48 hours. Therefore, in this paper, a low-cost, energy efficient oven operated by a solar energy collector was developed. This paper describes a feasibility study of the use of solar energy for curing ferro-geopolymer elements. The ferro-geopolymer elements made were beams with length 600 mm, width 100 mm and height 100 mm. Wire meshes with 6x6mm of opening were used in 5 layers. The solar energy collector system used as an oven was a zinc coated drum which was painted black outwardly and was covered by a glass plate. Using this oven, it was possible to increase the ambient temperature by 1.62 to 2,37 times. Furthermore, this oven can also increase the flexure strength of ferrogeopolymer elements about ± 25.34%. This paper shows good potential use of solar energy in the manufacturing of ferro-geopolymer elements in the semiarid region.

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