scholarly journals Piezoresistive Carbon Nanofiber-Based Cilia-Inspired Flow Sensor

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 211 ◽  
Author(s):  
Debarun Sengupta ◽  
Duco Trap ◽  
Ajay Giri Prakash Kottapalli
Keyword(s):  
Carbon Nanofiber ◽  
Detection Threshold ◽  
Flow Sensor ◽  
Oxygen Intake ◽  
Mems Devices ◽  
Flow Sensors ◽  
Flow Monitoring ◽  
Flow Sensing ◽  
Artificial Cilia ◽  
Lower Detection

Evolving over millions of years, hair-like natural flow sensors called cilia, which are found in fish, crickets, spiders, and inner ear cochlea, have achieved high resolution and sensitivity in flow sensing. In the pursuit of achieving such exceptional flow sensing performance in artificial sensors, researchers in the past have attempted to mimic the material, morphological, and functional properties of biological cilia sensors, to develop MEMS-based artificial cilia flow sensors. However, the fabrication of bio-inspired artificial cilia sensors involves complex and cumbersome micromachining techniques that lay constraints on the choice of materials, and prolongs the time taken to research, design, and fabricate new and novel designs, subsequently increasing the time-to-market. In this work, we establish a novel process flow for fabricating inexpensive, yet highly sensitive, cilia-inspired flow sensors. The artificial cilia flow sensor presented here, features a cilia-inspired high-aspect-ratio titanium pillar on an electrospun carbon nanofiber (CNF) sensing membrane. Tip displacement response calibration experiments conducted on the artificial cilia flow sensor demonstrated a lower detection threshold of 50 µm. Furthermore, flow calibration experiments conducted on the sensor revealed a steady-state airflow sensitivity of 6.16 mV/(m s−1) and an oscillatory flow sensitivity of 26 mV/(m s−1), with a lower detection threshold limit of 12.1 mm/s in the case of oscillatory flows. The flow sensing calibration experiments establish the feasibility of the proposed method for developing inexpensive, yet sensitive, flow sensors; which will be useful for applications involving precise flow monitoring in microfluidic devices, precise air/oxygen intake monitoring for hypoxic patients, and other biomedical devices tailored for intravenous drip/urine flow monitoring. In addition, this work also establishes the applicability of CNFs as novel sensing elements in MEMS devices and flexible sensors.

scholarly journals Development of an Ultra-Sensitive and Flexible Piezoresistive Flow Sensor Using Vertical Graphene Nanosheets

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Sajad Abolpour Moshizi ◽  
Shohreh Azadi ◽  
Andrew Belford ◽  
Amir Razmjou ◽  
Shuying Wu ◽  
...  
Keyword(s):  
Steady State ◽  
Graphene Nanosheets ◽  
Detection Threshold ◽  
Semicircular Canals ◽  
High Sensitivity ◽  
Flow Sensor ◽  
Rotational Axis ◽  
Low Velocity ◽  
Underwater Robots ◽  
Flow Monitoring

AbstractThis paper suggests development of a flexible, lightweight, and ultra-sensitive piezoresistive flow sensor based on vertical graphene nanosheets (VGNs) with a mazelike structure. The sensor was thoroughly characterized for steady-state and oscillatory water flow monitoring applications. The results demonstrated a high sensitivity (103.91 mV (mm/s)−1) and a very low-velocity detection threshold (1.127 mm s−1) in steady-state flow monitoring. As one of many potential applications, we demonstrated that the proposed VGNs/PDMS flow sensor can closely mimic the vestibular hair cell sensors housed inside the semicircular canals (SCCs). As a proof of concept, magnetic resonance imaging of the human inner ear was conducted to measure the dimensions of the SCCs and to develop a 3D printed lateral semicircular canal (LSCC). The sensor was embedded into the artificial LSCC and tested for various physiological movements. The obtained results indicate that the flow sensor is able to distinguish minute changes in the rotational axis physical geometry, frequency, and amplitude. The success of this study paves the way for extending this technology not only to vestibular organ prosthesis but also to other applications such as blood/urine flow monitoring, intravenous therapy (IV), water leakage monitoring, and unmanned underwater robots through incorporation of the appropriate packaging of devices.

scholarly journals Film Thickness-Profile Measurement Using Iterative Peak Separation Structured Illumination Microscopy

2021 ◽  
Vol 11 (7) ◽  
pp. 3023
Author(s):  
Kejun Yang ◽  
Chenhaolei Han ◽  
Jinhua Feng ◽  
Yan Tang ◽  
Zhongye Xie ◽  
...  
Keyword(s):  
Modulation Depth ◽  
Thickness Distribution ◽  
Detection Threshold ◽  
Profile Measurement ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Separation Algorithm ◽  
Peak Separation ◽  
Lower Detection ◽  
Depth Response

The surface and thickness distribution measurement for transparent film is of interest for electronics and packaging materials. Structured illumination microscopy (SIM) is a prospective technique for measuring film due to its high accuracy and efficiency. However, when the distance between adjacent layers becomes close, the peaks of the modulation depth response (MDR) start to overlap and interfere with the peak extraction, which restricts SIM development in the field of film measurement. In this paper, an iterative peak separation algorithm is creatively applied in the SIM-based technique, providing a precise peak identification even as the MDR peaks overlap and bend into one. Compared with the traditional method, the proposed method has a lower detection threshold for thickness. The experiments and theoretical analysis are elaborated to demonstrate the feasibility of the mentioned method.

Textile sensor for heat flow measurements

2016 ◽  
Vol 87 (2) ◽  
pp. 165-174
Author(s):  
Elena Onofrei ◽  
Teodor-Cezar Codau ◽  
Gauthier Bedek ◽  
Daniel Dupont ◽  
Cedric Cochrane
Keyword(s):  
Heat Flow ◽  
Human Body ◽  
Flow Sensor ◽  
Flow Sensors ◽  
Flow Measurements ◽  
Deformable Surfaces ◽  
Textile Sensor

This paper describes the concept of creating and testing of a textile heat flow sensor in order to determine the amount of heat exchanged between the human body and its environment. The main advantage of this sensor is the permeability to moisture, which allows taking into account the evaporation phenomenon, contrary to the traditional heat flow sensors. Another property related to this new sensor is its flexibility conferred by the textile substrate, which allows it to be applied on deformable surfaces.

Biomimetic flow sensors for biomedical flow sensing in intravenous tubes

2016 ◽  
Author(s):  
Zhiyuan Shen ◽  
Ajay Giri Prakash Kottapalli ◽  
Vignesh Subramaniam ◽  
Mohsen Asadnia ◽  
Jianmin Miao ◽  
...  
Keyword(s):  
Flow Sensors ◽  
Flow Sensing

Optically driven pumps and flow sensors for microfluidic systems

2008 ◽  
Vol 222 (5) ◽  
pp. 829-837 ◽  
Author(s):  
H Mushfique ◽  
J Leach ◽  
R Di Leonardo ◽  
M J Padgett ◽  
J M Cooper
Keyword(s):  
Fluid Flow ◽  
Optical Tweezers ◽  
Microfluidic Channel ◽  
Optical Traps ◽  
Spin Angular Momentum ◽  
Flow Sensors ◽  
Flow Sensing ◽  
Optically Trapped ◽  
Surrounding Fluid ◽  
Displace Fluid

This paper describes techniques for generating and measuring fluid flow in microfluidic devices. The first technique is for the multi-point measurement of fluid flow in microscopic geometries. The flow sensing method uses an array of optically trapped microprobe sensors to map out the fluid flow. The optical traps are alternately turned on and off such that the probe particles are displaced by the flow of the surrounding fluid and then retrapped. The particles' displacements are monitored by digital video microscopy and directly converted into velocity field values. The second is a method for generating flow within a microfluidic channel using an optically driven pump. The optically driven pump consists of two counter-rotating birefringent vaterite particles trapped within a microfluidic channel and driven using optical tweezers. The transfer of spin angular momentum from a circularly polarized laser beam causes the particles to rotate at up to 10 Hz. The pump is shown to be able to displace fluid in microchannels, with flow rates of up to 200 m−3 s−1 (200 fL s−1). In addition a flow sensing method, based upon the technique mentioned above, is incorporated into the system in order to map the magnitude and direction of fluid flow within the channel.

scholarly journals Discerning the role of mechanosensors in regulating proximal tubule function

2016 ◽  
Vol 310 (1) ◽  
pp. F1-F5 ◽  
Author(s):  
Venkatesan Raghavan ◽  
Ora A. Weisz
Keyword(s):  
Shear Stress ◽  
Proximal Tubule ◽  
Primary Cilia ◽  
The Body ◽  
Flow Sensors ◽  
Body Experience ◽  
Flow Sensing ◽  
Axial Shear ◽  
Stretch Activated Channels

All cells in the body experience external mechanical forces such as shear stress and stretch. These forces are sensed by specialized structures in the cell known as mechanosensors. Cells lining the proximal tubule (PT) of the kidney are continuously exposed to variations in flow rates of the glomerular ultrafiltrate, which manifest as changes in axial shear stress and radial stretch. Studies suggest that these cells respond acutely to variations in flow by modulating their ion transport and endocytic functions to maintain glomerulotubular balance. Conceptually, changes in the axial shear stress in the PT could be sensed by three known structures, namely, the microvilli, the glycocalyx, and primary cilia. The orthogonal component of the force produced by flow exhibits as radial stretch and can cause expansion of the tubule. Forces of stretch are transduced by integrins, by stretch-activated channels, and by cell-cell contacts. This review summarizes our current understanding of flow sensing in PT epithelia, discusses challenges in dissecting the role of individual flow sensors in the mechanosensitive responses, and identifies potential areas of opportunity for new study.

scholarly journals Thermal Flow Sensors for Harsh Environments

2017 ◽  
Author(s):  
Vivekananthan Balakrishnan ◽  
Hoang-Phuong Phan ◽  
Toan Dinh ◽  
Dzung Viet Dao ◽  
Nam-Trung Nguyen
Keyword(s):  
Fluid Flows ◽  
Harsh Environments ◽  
Thermal Flow ◽  
Hostile Environment ◽  
Flow Sensors ◽  
Flow Sensing ◽  
Thermal Flow Sensor ◽  
Transduction Mechanisms ◽  
Operational Modes ◽  
Higher Sensitivity

Flow sensing in hostile environment is of increasing interest for applications in automotive, aerospace, and chemical and resource industries. Compared to their counterparts, thermal flow sensors are attractive candidates due to the ease of fabrication, lack of moving parts and higher sensitivity. Recently, a number of thermal flow sensor prototypes have been reported in the literature demonstrating the measurement of fluid flows under hostile conditions. This paper summarizes the concept of thermal flow sensing, operational modes and transduction mechanisms. Then, the choice of materials and their corresponding properties are presented in details. The paper also reports recent progress in the development of thermal flow sensors for harsh environment. In addition, the issues and considerations in packaging are reviewed. Finally, we conclude the review with the future prospects.

scholarly journals Evaluation of the Performance Characteristics of the Lightning Imaging Sensor

2019 ◽  
Vol 36 (6) ◽  
pp. 1015-1031 ◽  
Author(s):  
Daile Zhang ◽  
Kenneth L. Cummins ◽  
Phillip Bitzer ◽  
William J. Koshak
Keyword(s):  
Detection Threshold ◽  
Tropical Rainfall Measuring Mission ◽  
Performance Characteristics ◽  
Viewing Angle ◽  
Lightning Detection ◽  
Laboratory Calibration ◽  
Lower Detection ◽  
Pixel Array ◽  
Radio Signals ◽  
Imaging Sensor

AbstractThe Lightning Imaging Sensor (LIS) that was on board the Tropical Rainfall Measuring Mission (TRMM) satellite captured optical emissions produced by lightning. In this work, we quantify and evaluate the LIS performance characteristics at both the pixel level of LIS events and contiguous clusters of events known as groups during a recent 2-yr period. Differences in the detection threshold among the four quadrants in the LIS pixel array produce small but meaningful differences in their optical characteristics. In particular, one LIS quadrant (Q1, X ≥ 64; Y ≥ 64) detects 15%–20% more lightning events than the others because of a lower detection threshold. Sensitivity decreases radially from the center of the LIS array to the edges because of sensor optics. The observed falloff behavior is larger on orbit than was measured during the prelaunch laboratory calibration and is likely linked to changes in cloud scattering pathlength with instrument viewing angle. Also, a two-season comparison with the U.S. National Lightning Detection Network (NLDN) has uncovered a 5–7-km north–south LIS location offset that changes sign because of periodic TRMM yaw maneuvers. LIS groups and flashes that had any temporally and spatially corresponding NLDN reports (i.e., NLDN reported the radio signals from the same group and/or from other groups in the same flash) tended to be spatially larger and last longer (only for flashes) than the overall population of groups/flashes.

Low-Magnitude Earthquakes at the Eastern Ultraslow-Spreading Gakkel Ridge, Arctic Ocean

2021 ◽  
Author(s):  
Alexey Nikolaevich Morozov ◽  
Natalya V. Vaganova ◽  
Galina N. Antonovskaya ◽  
Vladimir E. Asming ◽  
Irina P. Gabsatarova ◽  
...  
Keyword(s):  
Detection Threshold ◽  
Global Network ◽  
Relative Location ◽  
Gakkel Ridge ◽  
Svalbard Archipelago ◽  
Local Seismicity ◽  
Seismic Stations ◽  
Lower Detection ◽  
Severnaya Zemlya ◽  
Over Time

Abstract Thanks to the new permanent seismic stations installed in the Franz Joseph Land and Severnaya Zemlya arctic archipelagoes, it has become possible at present to record earthquakes occurring in the eastern Gakkel ridge with a much lower detection threshold than that provided by the global network. At present, the lowest recorded magnitude is ML 2.4 and the magnitude of completeness is 3.4. We examined the results of seismic monitoring conducted from December 2016 through January 2020 to show that the earthquake epicenters are not uniformly distributed both in space and over time within the eastern part of the ridge. There were periods of quiescence and seismic activity. Most of the epicenters are confined to the area between 86° and 95.0° E. Relative location techniques were used to locate the single major swarm of earthquakes recorded so far. Most earthquakes were recorded by two or three stations only, so that relative location techniques have been able to yield reliable data for an analysis of the swarm. We showed that there have been actually two swarms that contained different numbers of events. The earthquakes in the larger swarm were occurring nonuniformly over time and clustered at certain depths. The ML scale was calibrated for the Eurasian Arctic based on records of the seismic stations installed in the Svalbard Archipelago, Franz Joseph Land, and on Severnaya Zemlya: −logA0(R)=1.5×logR100+1.0×10−4(R−100)+3.0. The results will help expand our knowledge of the tectonic and magmatic processes occurring within the ultraslow Gakkel ridge, which are reflected in the local seismicity.

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