Artykuły w czasopismach: „Cantilever Flow Sensor”

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Abels, Claudio, Antonio Qualtieri, Toni Lober, Alessandro Mariotti, Lily D. Chambers, Massimo De Vittorio, William M. Megill i Francesco Rizzi. "Bidirectional biomimetic flow sensing with antiparallel and curved artificial hair sensors". Beilstein Journal of Nanotechnology 10 (3.01.2019): 32–46. http://dx.doi.org/10.3762/bjnano.10.4.

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Background: Flow stimuli in the natural world are varied and contain a wide variety of directional information. Nature has developed morphological polarity and bidirectional arrangements for flow sensing to filter the incoming stimuli. Inspired by the neuromasts found in the lateral line of fish, we present a novel flow sensor design based on two curved cantilevers with bending orientation antiparallel to each other. Antiparallel cantilever pairs were designed, fabricated and compared to a single cantilever based hair sensor in terms of sensitivity to temperature changes and their response to changes in relative air flow direction. Results: In bidirectional air flow, antiparallel cantilever pairs exhibit an axially symmetrical sensitivity between 40 μV/(m s−1) for the lower air flow velocity range (between ±10–20 m s−1) and 80 μV/(m s−1) for a higher air flow velocity range (between ±20–32 m s−1). The antiparallel cantilever design improves directional sensitivity and provides a sinusoidal response to flow angle. In forward flow, the single sensor reaches its saturation limitation, flattening at 67% of the ideal sinusoidal curve which is earlier than the antiparallel cantilevers at 75%. The antiparallel artificial hair sensor better compensates for temperature changes than the single sensor. Conclusion: This work demonstrated the successive improvement of the bidirectional sensitivity, that is, improved temperature compensation, decreased noise generation and symmetrical response behaviour. In the antiparallel configuration, one of the two cantilevers always extends out into the free stream flow, remaining sensitive to directional flow and preserving a sensitivity to further flow stimuli.

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Stauffenberg, Jaqueline, Steve Durstewitz, Martin Hofmann, Tzvetan Ivanov, Mathias Holz, Waleed Ehrhardt, Wolf-Ulrich Riegel, Jens-Peter Zöllner, Eberhard Manske i Ivo Rangelow. "Determination of the mixing ratio of a flowing gas mixture with self-actuated microcantilevers". Journal of Sensors and Sensor Systems 9, nr 1 (27.02.2020): 71–78. http://dx.doi.org/10.5194/jsss-9-71-2020.

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Abstract. Microcantilevers offer a wide range of applications in sensor and measurement technology. In this work cantilever sensors are used as flow sensors. Most conventional flow sensors are often only calibrated for one type of gas and allow an analysis of gas mixtures only with increased effort. The sensor used here is a cantilever positioned vertically in the flow channel. It is possible to operate the sensor in dynamic and static mode. In the dynamic mode the cantilever is oscillating. Resonance frequency, resonance amplitude and phase are measured. In static mode, the bending of the cantilever is registered. The combination of the modes enables the different measured variables to be determined simultaneously. A flow influences the movement behaviour of the sensor, which allows the flow velocity to be deduced. In addition to determining the flow velocity, it is also possible to detect different types of gas. Each medium has certain properties (density and viscosity) which have different effects on the bending of the sensor. As a result, it is possible to measure the mixing ratio of a known binary gas mixture and their flow velocity simultaneously with a single sensor. In this paper this is investigated using the example of the air–carbon-dioxide mixture.

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Hetrick, Robert E. "Vibrating cantilever mass flow sensor". Sensors and Actuators A: Physical 21, nr 1-3 (luty 1990): 373–76. http://dx.doi.org/10.1016/0924-4247(90)85074-e.

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Lee, Chia Yen, Yu Hsiang Wang, Tzu Han Hsueh, Rong Hua Ma, Lung Ming Fu i Po Cheng Chou. "A Smart Flow Sensor for Flow Direction Measurement". Advanced Materials Research 47-50 (czerwiec 2008): 189–92. http://dx.doi.org/10.4028/www.scientific.net/amr.47-50.189.

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The purpose of this paper is to apply MEMS techniques to manufacture a gas flow sensor that consists with an airflow rate and airflow direction sensing units for detection of airflow states. This study uses a silicon wafer as a substrate which is deposited silicon nitride layers. To form the airflow rate sensing unit, a micro heater and a sensing resistor are manufactured over a membrane that released by a back-etching process. The airflow direction sensing unit is made of four cantilever beams that perpendicular to each other and integrated with piezoresistive structure on each micro-cantilever, respectively. As the cantilever beams are formed after etching the silicon wafer, it bends up a little due to the released residual stress induced in the previous fabrication process. As air flows through the airflow rate sensor, the temperature of the sensing resistor decreases and the evaluation of the local temperature changes determines the airflow rate. On the proposed sensor, the airflow direction can be determined through comparing the resistance variation caused by different deformation of cantilever beams at different directions.

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Pommois, Romain, Gaku Furusawa, Takuya Kosuge, Shun Yasunaga, Haruki Hanawa, Hidetoshi Takahashi, Tetsuo Kan i Hisayuki Aoyama. "Micro Water Flow Measurement Using a Temperature-Compensated MEMS Piezoresistive Cantilever". Micromachines 11, nr 7 (30.06.2020): 647. http://dx.doi.org/10.3390/mi11070647.

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In this study, we propose a microelectromechanical system (MEMS) force sensor for microflow measurements. The sensor is equipped with a flow sensing piezoresistive cantilever and a dummy piezoresistive cantilever, which acts as a temperature reference. Since the dummy cantilever is also in the form of a thin cantilever, the temperature environment of the dummy sensor is almost identical to that of the sensing cantilever. The temperature compensation effect was measured, and the piezoresistive cantilever was combined with a gasket jig to enable the direct implementation of the piezoresistive cantilever in a flow tube. The sensor device stably measured flow rates from 20 μL/s to 400 μL/s in a silicon tube with a 2-mm inner diameter without being disturbed by temperature fluctuations.

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Bertke, Maik, Jiushuai Xu, Michael Fahrbach, Andi Setiono, Hutomo Wasisto i Erwin Peiner. "Strategy toward Miniaturized, Self-out-Readable Resonant Cantilever and Integrated Electrostatic Microchannel Separator for Highly Sensitive Airborne Nanoparticle Detection". Sensors 19, nr 4 (21.02.2019): 901. http://dx.doi.org/10.3390/s19040901.

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In this paper, a self-out-readable, miniaturized cantilever resonator for highly sensitive airborne nanoparticle (NP) detection is presented. The cantilever, which is operated in the fundamental in-plane resonance mode, is used as a microbalance with femtogram resolution. To maximize sensitivity and read-out signal amplitude of the piezo-resistive Wheatstone half bridge, the geometric parameters of the sensor design are optimized by finite element modelling (FEM). The electrical read-out of the cantilever movement is realized by piezo-resistive struts at the sides of the cantilever resonator that enable real-time tracking using a phase-locked loop (PLL) circuit. Cantilevers with minimum resonator mass of 1.72 ng and resonance frequency of ~440 kHz were fabricated, providing a theoretical sensitivity of 7.8 fg/Hz. In addition, for electrostatic NP collection, the cantilever has a negative-biased electrode located at its free end. Moreover, the counter-electrode surrounding the cantilever and a µ-channel, guiding the particle-laden air flow towards the cantilever, are integrated with the sensor chip. µ-channels and varying sampling voltages will also be used to accomplish particle separation for size-selective NP detection. To sum up, the presented airborne NP sensor is expected to demonstrate significant improvements in the field of handheld, micro-/nanoelectromechanical systems (M/NEMS)-based NP monitoring devices.

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Ghommem, Mehdi, Victor M. Calo i Christian G. Claudel. "Micro-cantilever flow sensor for small aircraft". Journal of Vibration and Control 21, nr 10 (październik 2013): 2043–58. http://dx.doi.org/10.1177/1077546313505636.

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Zöllner, Jens-Peter, Steve Durstewitz, Jaqueline Stauffenberg, Tzvetan Ivanov, Mathias Holz, Waleed Ehrhardt, W. Ulrich Riegel i Ivo W. Rangelow. "Gas-Flow Sensor Based on Self-Oscillating and Self-Sensing Cantilever". Proceedings 2, nr 13 (3.12.2018): 846. http://dx.doi.org/10.3390/proceedings2130846.

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In this work the application of a self-sensing and self-actuating cantilever for gas-flow measurement is investigated. The cantilever placed in the flow is excited permanently at its first resonance mode. Simultaneously the resonance amplitude, the resonance frequency and the static bending of the cantilever are detected. All three sizes are related to the velocity of the gas-flow.

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Aparna, Dr K. Durga, K. L. V. Nagasree i G. Lalitha Devi. "Design and Fabrication of Mems U-Shaped Cantilever". International Journal of Recent Technology and Engineering (IJRTE) 11, nr 6 (30.03.2023): 80–83. http://dx.doi.org/10.35940/ijrte.f7496.0311623.

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MEMS are used in acceleration, flow, pressure and force sensing applications on the micro and macro levels. The fundamental part of every sensor is the transducer which converts the measurend of intrest into and interpretable output signal. The most prominent transducer is the piezoresistive cantilever which translates any signal into an electrical signal.This paper presents the deisgn and fabrication of U shaped cantilever with enhanced sensitivity and stiffness which gives better results than other cantilevers. The simulation results of the cantilevers are designed using COMSOL software. MEMS technology becomes more affordable better and easier to fabricate in increasing quantities. Each layer of fabrication process is quite complex and final fabricated product will tested and used for high end applications.

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Nakashima, Rihachiro, i Hidetoshi Takahashi. "Biaxial Angular Acceleration Sensor with Rotational-Symmetric Spiral Channels and MEMS Piezoresistive Cantilevers". Micromachines 12, nr 5 (30.04.2021): 507. http://dx.doi.org/10.3390/mi12050507.

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Angular acceleration sensors are attracting attention as sensors for monitoring rotational vibration. Many angular acceleration sensors have been developed; however, multiaxis measurement is still in a challenging stage. In this study, we propose a biaxial angular acceleration sensor with two uniaxial sensor units arranged orthogonally. The sensor units consist of two rotational-symmetric spiral channels and microelectromechanical system (MEMS) piezoresistive cantilevers. The cantilever is placed to interrupt the flow at the junctions of parallelly aligned spirals in each channel. When two cantilevers are used as the resistance of the bridge circuit in the two-gauge method, the rotational-symmetric spiral channels enhance the sensitivity in the target axis, while the nontarget axis sensitivities are canceled. The fabricated device responds with approximately constant sensitivity from 1 to 15 Hz, with a value of 3.86 × 10−5/(rad/s2), which is equal to the theoretical value. The nontarget axis sensitivity is approximately 1/400 of the target axis sensitivity. In addition, we demonstrate that each unit responds according to the tilt angle when the device is tilted along the two corresponding rotational axis planes. Thus, it is concluded that the developed device realizes biaxial angular acceleration measurement with low crosstalk.

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Segawa, Takehiko, Daiki Suzuki, Takayasu Fujino, Timothy Jukes i Takayuki Matsunuma. "Feedback Control of Flow Separation Using Plasma Actuator and FBG Sensor". International Journal of Aerospace Engineering 2016 (2016): 1–16. http://dx.doi.org/10.1155/2016/8648919.

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A feedback control system for mitigating flow separation was developed by using a string-type dielectric-barrier-discharge (DBD) plasma actuator and a fiber Bragg grating (FBG) sensor. Tangential jets were induced from the string-type DBD plasma actuator, which was located at 5% chord from the leading edge of an NACA0024 airfoil. The FBG sensor was attached to the interior surface near the root of the cantilever beam modeled on the pressure surface of the airfoil. The strain at the cantilever root was reflected in the form of Bragg wavelengths (λB) detected by the FBG sensor when the cantilever tip was vibrated by the flow near the trailing edge of the airfoil. It was found that calculating running standard deviations in the Bragg wavelength (λB′) detected by the sensor was valuable for judging flow separation in real time. The feedback control of flow separation on the NACA0024 airfoil was successfully demonstrated by setting λB′=0.0028 with periodic flow separations generated in a wind tunnel by oscillating a side wall of the test section with frequency fw=0.42 Hz. It was confirmed that the appearance probability of flow separation tends to decrease with a decrease in the duration for calculating λB′ and with an increase in the duration of jet injection.

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Bertke, Maik, Jiushuai Xu, Michael Fahrbach, Andi Setiono, Gerry Hamdana, Hutomo Suryo Wasisto i Erwin Peiner. "Design of Miniaturized, Self-Out-Readable Cantilever Resonator for Highly Sensitive Airborne Nanoparticle Detection". Proceedings 2, nr 13 (3.12.2018): 879. http://dx.doi.org/10.3390/proceedings2130879.

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In this paper, a self-out-readable, miniaturized cantilever resonator for highly sensitiveairborne nanoparticle (NP) detection is presented. The cantilever, which is operated in thefundamental in-plane resonance mode, is used as a microbalance with femtogram resolution. Toachieve a maximum measurement signal of the piezo resistive Wheatstone half-bridge, thegeometric parameters of the sensor design were optimized by finite element modelling (FEM).Struts at the sides of the cantilever resonator act as piezo resistors and enable an electrical read-outof the phase information of the cantilever movement whereby they do not contribute to theresonators rest mass. For the optimized design, a resonator mass of 0.93 ng, a resonance frequencyof ~440 kHz, and thus a theoretical sensitivity of 4.23 fg/Hz can be achieved. A μ-channel guiding aparticle-laden air flow towards the cantilever is integrated into the sensor chip. Electrically chargedNPs will be collected by an electrostatic field between the cantilever and a counter-electrode at theedges of the μ-channel. Such μ-channels will also be used to accomplish particle separation for sizeselectiveNP detection. Throughout, the presented airborne NP sensor is expected to demonstratesignificant improvements in the field of handheld, MEMS-based NP monitoring devices.

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NOMURA, Takehiro, Hiroyuki ABE, Yoshihiro KIKUSHIMA i Masahide MURAKAMI. "Detection of Flow Separation on Aerofoil by FBG Cantilever Sensor". JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES 56, nr 653 (2008): 249–55. http://dx.doi.org/10.2322/jjsass.56.249.

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Zhang, Songsong, Liang Lou i Chengkuo Lee. "Piezoresistive silicon nanowire based nanoelectromechanical system cantilever air flow sensor". Applied Physics Letters 100, nr 2 (9.01.2012): 023111. http://dx.doi.org/10.1063/1.3675878.

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Zhang, Songsong, Liang Lou, Woo-Tae Park i Chengkuo Lee. "Characterization of a silicon nanowire-based cantilever air-flow sensor". Journal of Micromechanics and Microengineering 22, nr 9 (26.07.2012): 095008. http://dx.doi.org/10.1088/0960-1317/22/9/095008.

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Zhao, Ran, Qingjie Yuan, Jianwu Yan i Qanguo Lu. "The Static and Dynamic Sensitivity of Magnetostrictive Bioinspired Whisker Sensor". Journal of Nanotechnology 2018 (2018): 1–6. http://dx.doi.org/10.1155/2018/2591080.

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Magnetostrictive bioinspired whisker is a new kind of sensor that can realize tactile and flow sensing by utilizing magnetoelastic effect. The sensitivity is a key technical indicator of whisker sensor. The paper presented a new magnetostrictive whisker based on Galfenol cantilever beam, as well as its operation principle. Then, the static and dynamic sensitivity of the whisker sensor was investigated by using a self-made experimental system. The results illustrated that the proposed sensor has a high sensitivity. Its static sensitivity is 2.2 mV/mN. However, its dynamic sensitivity depends on the vibration frequency. When working at the natural frequency of the cantilever beam, the dynamic sensitivity performs an obvious increase—1.3 mV/mN at 3.5 Hz (the first-order natural frequency) and 2.1 mV/mN at 40 Hz (the second-order natural frequency), respectively.

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Park, Byung Kyu, i Joon Sik Lee. "Wireless Telemetry of an Oscillating Flow using Mesoscale Flexible Cantilever Sensor". Transactions of the Korean Society of Mechanical Engineers B 37, nr 5 (1.05.2013): 495–501. http://dx.doi.org/10.3795/ksme-b.2013.37.5.495.

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Naveen, Harija, Shankar Narasimhan, Boby George i Arun K. Tangirala. "Design and Development of a Low-Cost Cantilever-Based Flow Sensor". IFAC-PapersOnLine 53, nr 1 (2020): 111–16. http://dx.doi.org/10.1016/j.ifacol.2020.06.019.

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Kamat, Amar M., Yutao Pei i Ajay G. P. Kottapalli. "Bioinspired Cilia Sensors with Graphene Sensing Elements Fabricated Using 3D Printing and Casting". Nanomaterials 9, nr 7 (30.06.2019): 954. http://dx.doi.org/10.3390/nano9070954.

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Sensor designs found in nature are optimal due to their evolution over millions of years, making them well-suited for sensing applications. However, replicating these complex, three-dimensional (3D), biomimetic designs in artificial and flexible sensors using conventional techniques such as lithography is challenging. In this paper, we introduce a new processing paradigm for the simplified fabrication of flexible sensors featuring complex and bioinspired structures. The proposed fabrication workflow entailed 3D-printing a metallic mold with complex and intricate 3D features such as a micropillar and a microchannel, casting polydimethylsiloxane (PDMS) inside the mold to obtain the desired structure, and drop-casting piezoresistive graphene nanoplatelets into the predesigned microchannel to form a flexible strain gauge. The graphene-on-PDMS strain gauge showed a high gauge factor of 37 as measured via cyclical tension-compression tests. The processing workflow was used to fabricate a flow sensor inspired by hair-like ‘cilia’ sensors found in nature, which comprised a cilia-inspired pillar and a cantilever with a microchannel that housed the graphene strain gauge. The sensor showed good sensitivity against both tactile and water flow stimuli, with detection thresholds as low as 12 µm in the former and 58 mm/s in the latter, demonstrating the feasibility of our method in developing flexible flow sensors.

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Sharma, Vandana, S. L. Shimi, Saleem Khan i Sandeep Arya. "Design and Fluid Structure Interaction Analysis of a Micro-Channel as Fluid Sensor". Advanced Engineering Forum 14 (październik 2015): 46–56. http://dx.doi.org/10.4028/www.scientific.net/aef.14.46.

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In this proposed work, the design and analysis of a flow sensor to be integrated into a micro-channel is presented. A finite element analysis is carried out to simulate fluid-structure interaction and estimate cantilever deflection under different fluidic flows at constant flow rate. The design of device is based on the determination of geometrical dimensions. A mathematical analysis describing the fluid mechanics and their interaction with the beam is also proposed. The mathematical model is done using finite-element analysis, and a complete formulation for design analysis is determined. Finite element method based Comsol Multiphysics simulations are used to optimize the design in order to determine the fluid velocities after interaction with the free end of the micro-cantilever beam. The device is successfully designed for sensing different fluids.

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Bertke, Maik, Ina Kirsch, Erik Uhde i Erwin Peiner. "Ultrafine Aerosol Particle Sizer Based on Piezoresistive Microcantilever Resonators with Integrated Air-Flow Channel". Sensors 21, nr 11 (27.05.2021): 3731. http://dx.doi.org/10.3390/s21113731.

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To monitor airborne nano-sized particles (NPs), a single-chip differential mobility particle sizer (DMPS) based on resonant micro cantilevers in defined micro-fluidic channels (µFCs) is introduced. A size bin of the positive-charged fraction of particles herein is separated from the air stream by aligning their trajectories onto the cantilever under the action of a perpendicular electrostatic field of variable strength. We use previously described µFCs and piezoresistive micro cantilevers (PMCs) of 16 ng mass fabricated using micro electro mechanical system (MEMS) technology, which offer a limit of detection of captured particle mass of 0.26 pg and a minimum detectable particulate mass concentration in air of 0.75 µg/m3. Mobility sizing in 4 bins of a nebulized carbon aerosol NPs is demonstrated based on finite element modelling (FEM) combined with a-priori knowledge of particle charge state. Good agreement of better than 14% of mass concentration is observed in a chamber test for the novel MEMS-DMPS vs. a simultaneously operated standard fast mobility particle sizer (FMPS) as reference instrument. Refreshing of polluted cantilevers is feasible without de-mounting the sensor chip from its package by multiply purging them alternately in acetone steam and clean air.

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Bai, Yang, Hana Hughes, Pavel Tofel, Carl Meggs i Tim W. Button. "Fabrication and Characterization of Vibration and Wind Energy Harvesters Using Multilayer Free-Standing Piezoelectric Thick Films". Journal of Microelectronics and Electronic Packaging 12, nr 4 (1.10.2015): 181–88. http://dx.doi.org/10.4071/imaps.483.

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This article demonstrates the feasibility of fabricating energy harvesters based on piezoelectric cantilevers with a free-standing thick-film structure. Demonstrator devices have been designed, built, and evaluated in a range of mechanical coupling configurations to harvest energy from machinery vibrations and weak air flow. In terms of wideband vibration energy harvesters, arrays of the individual harvesters were assembled onto plastic test circuit boards integrated with diode bridge rectifiers. The harvesters were designed with different dimensions, and various tip masses were attached on the tip of the cantilevers to individually tune the resonant frequencies. The assembled harvesters were tested under harmonic vibration conditions. Great potential of harvesting vibration energy and broadening working bandwidth has been exhibited. In terms of the harvester for weak air flow, two individual cantilever devices were assembled on the chassis of a free-spinning fan. Permanent magnets were fixed on the blades of the fan as well as on the cantilevers. The device was tested in an open fluidic environment. The air flow was successfully transferred to axial oscillations, thus driving the cantilevers bending up and down. Possibilities of such devices being optimized to meet the requirements of real applications of self-powered wireless sensor networks can be foreseen.

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Bai, Yang, Hana Hughes, Pavel Tofel, Carl Meggs i Tim W. Button. "Fabrication and Characterisation of Vibration and Wind Energy Harvesters Using Multi-layer Free-standing Piezoelectric Thick-films". Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2015, CICMT (1.09.2015): 000195–202. http://dx.doi.org/10.4071/cicmt-wa34.

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This paper demonstrates the feasibility of fabricating energy harvesters based on piezoelectric cantilevers with a free-standing thick-film structure. Demonstrator devices have been designed, built and evaluated in a range of mechanical coupling configurations, in order to harvest energy from machinery vibrations and weak air flow. In terms of wideband vibration energy harvesters, arrays of the individual harvesters were assembled onto plastic test circuit boards integrated with diode bridge rectifiers. The harvesters were designed with different dimensions and various tip masses were attached on the tip of the cantilevers in order to individually tune the resonant frequencies. The assembled harvesters were tested under harmonic vibration conditions. Great potential of harvesting vibration energy and broadening working bandwidth has been exhibited. In terms of the harvester for weak air flow, two individual cantilever devices were assembled on the chassis of a free-spinning fan. Permanent magnets were fixed on the blades of the fan as well as the cantilevers. The device was tested in an open fluidic environments. The air flow has been successfully transferred to axial oscillations thus driving the cantilevers bending up and down. Possibilities of such devices being optimised to meet the requirements of real applications of self-powered wireless sensor networks can be foreseen.

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Qi, Jiali, Chun Shao, Wei Wu i Ruijin Wang. "Investigation on the Effective Measures for Improving the Performance of Calorimetric Microflow Sensor". Sensors 23, nr 17 (25.08.2023): 7413. http://dx.doi.org/10.3390/s23177413.

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The performance of the calorimetric microflow sensor is closely related to the thermal sensing part design, including structure parameter, heater temperature, and operation environment. In this paper, several measures to enhance the performance of the calorimetric microflow sensor were proposed and further verified by numerical simulations. The results demonstrate that it is more favorable to reduce the negative impact of flow separation as the space between detectors and heater is set to be 1.6 μm so as to improve the accuracy of the sensor. With an appropriate gap, the front arranged obstacle of the upstream detector can effectively widen the measure range of the sensor, benefiting from the decrease in upstream viscous dissipation. Compared to a cantilever structure, the resonances can be effectively suppressed when the heater and detectors are designed as bridge structures. In particular, the maximum amplitude of the bridge structure is only 0.022 μm at 70 sccm, which is 53% lower than that of the cantilever structure. The optimized sensor widens the range by 14.3% and significantly increases the sensitivity at high flow rates. Moreover, the feasibility of the improved measures is also illustrated via the consistency of the trend between the simulation results and experimental ones.

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Harija, H., Boby George i Arun K. Tangirala. "A Cantilever-Based Flow Sensor for Domestic and Agricultural Water Supply System". IEEE Sensors Journal 21, nr 23 (1.12.2021): 27147–56. http://dx.doi.org/10.1109/jsen.2021.3121306.

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Blue, Robert, James G. Brown, Lijie Li, Ralf Bauer i Deepak Uttamchandani. "MEMS Gas Flow Sensor Based on Thermally Induced Cantilever Resonance Frequency Shift". IEEE Sensors Journal 20, nr 8 (15.04.2020): 4139–46. http://dx.doi.org/10.1109/jsen.2020.2964323.

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Qualtieri, A., F. Rizzi, M. T. Todaro, A. Passaseo, R. Cingolani i M. De Vittorio. "Stress-driven AlN cantilever-based flow sensor for fish lateral line system". Microelectronic Engineering 88, nr 8 (sierpień 2011): 2376–78. http://dx.doi.org/10.1016/j.mee.2011.02.091.

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Bučinskas, Vytautas, Andrius Dzedzickis, Ernestas Šutinys i Tadas Lenkutis. "Implementation of Different Gas Influence for Operation of Modified Atomic Force Microscope Sensor". Solid State Phenomena 260 (lipiec 2017): 99–104. http://dx.doi.org/10.4028/www.scientific.net/ssp.260.99.

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This paper presents modelling of various gas application to modified atomic force microscope sensor in order to change its existing dynamic characteristics. This paper represents part of continuous research, which is focused on improvement of scanning speed of atomic force microscope (AFM) sensor. Subject of our research is enhancement of dynamic characteristics of Atomic force microscope sensor. Natural frequency of AFM sensor is the main factor influencing max scanning speed of atomic force microscope. In case of working range of frequencies approaches to the resonant frequency of cantilever, scanning results becoming inaccurate and unreliable. Improvement of properties of atomic force sensor made by adding additional nonlinear aerodynamic force to the AFM sensor. This force would act as additional controllable stiffness element, which allows shift resonant frequency to higher side. In this paper is presented research of additional nonlinear force behavior using different gasses as well as compressed air. Research covers factor of humidity of compressed air. Our research performed using 3D atomic microscope cantilever model in SolidWorks flow simulation software. Results of simulation delivered as dependencies of additional stiffness in the AFM sensor in all modelled cases. Finally, results presented in graphical form and conclusions are drawn.

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Wang, Yu-Hsiang, Chia-Yen Lee i Che-Ming Chiang. "A MEMS-based Air Flow Sensor with a Free-standing Micro-cantilever Structure". Sensors 7, nr 10 (17.10.2007): 2389–401. http://dx.doi.org/10.3390/s7102389.

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Singh, Rahul Kumar, Sun Woh Lye i Jianmin Miao. "PVDF Nanofiber Sensor for Vibration Measurement in a String". Sensors 19, nr 17 (29.08.2019): 3739. http://dx.doi.org/10.3390/s19173739.

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Flexible, self-powered and miniaturized sensors are extensively used in the areas of sports, soft robotics, health care and communication devices. Measurement of vibration is important for determining the mechanical properties of a structure, specifically the string tension in strings. In this work, a flexible, lightweight and self-powered sensor is developed and attached to a string to measure vibrations characteristics in strings. Electrospun poly(vinylidene) fluoride (PVDF) nanofibers are deposited on a flexible liquid crystal polymer (LCP) substrate for the development of the sensor. The electrospinning process is optimized for different needle sizes (0.34–0.84 mm) and flow rates (0.6–3 mL/h). The characterization of the sensor is done in a cantilever configuration and the test results indicate the sensor’s capability to measure the frequency and strain in the required range. The comparison of the results from the developed PVDF sensor and a commercial Laser Displacement Sensor (LDS) showed good resemblance (±0.2%) and a linear voltage profile (0.2 mV/με). The sensor, upon attachment to a racket string, is able to measure single impacts and sinusoidal vibrations. The repeatability of the results on the measurement of vibrations produced by an impact hammer and a mini shaker demonstrate an exciting new application for piezoelectric sensors.

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Zhang, Zhuoliang, Chao Zhou, Zhiqiang Cao, Min Tan, Long Cheng, Sai Deng i Junfeng Fan. "A speed measurement method for underwater robots using an artificial lateral line sensor". Smart Materials and Structures 31, nr 1 (22.11.2021): 015011. http://dx.doi.org/10.1088/1361-665x/ac358e.

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Abstract Underwater robot technology has made considerable progress in recent years. However, due to the harsh environment and noise in the flow field near the underwater robots, it is difficult to measure some basic parameters, including swimming speed. The traditional speed measurement methods for underwater robots have the disadvantages of being limited by the environment and bulky. In order to overcome these shortcomings, an artificial lateral line (ALL) sensor based on cantilever structure was developed in this paper. According to the deformation of cantilever beam under water impact, the swimming speed of underwater robots can be measured. In addition, an ‘end-to-end’ calibration algorithm was proposed to calibrate the ALL sensor in the noisy environment, avoiding the complicated noise modeling and filter design process. To reduce the risk of overfitting, a hybrid loss function based on physical model was adopted. Compared with the classical calibration method, our method can reduce the error by 47.8%. Our sensor achieved an average absolute error of 0.07897 m s−1, and can measure water speed up to 3 m s−1.

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Wang, Peng, Yujun Yang, Manlong Chen, Changming Zhang, Nan Wang, Fan Yang, Chunlei Peng, Jike Han i Yuqiang Dai. "Design of a Biaxial High-G Piezoresistive Accelerometer with a Tension–Compression Structure". Micromachines 14, nr 8 (25.07.2023): 1492. http://dx.doi.org/10.3390/mi14081492.

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To meet the measurement needs of multidimensional high-g acceleration in fields such as weapon penetration, aerospace, and explosive shock, a biaxial piezoresistive accelerometer incorporating tension–compression is meticulously designed. This study begins by thoroughly examining the tension–compression measurement mechanism and designing the sensor’s sensitive structure. A signal test circuit is developed to effectively mitigate cross-interference, taking into account the stress variation characteristics of the cantilever beam. Subsequently, the signal test circuit of anti-cross-interference is designed according to the stress variation characteristics of the cantilever beam. Next, the finite element method is applied to analyze the structure and obtain the performance indices of the range, vibration modes, and sensitivity of the sensor. Finally, the process flow and packaging scheme of the chip are analyzed. The results show that the sensor has a full range of 200,000 g, a sensitivity of 1.39 µV/g in the X direction and 1.42 µV/g in the Y direction, and natural frequencies of 509.8 kHz and 510.2 kHz in the X and Y directions, respectively.

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Chadwick, K. M., D. J. DeTurris i J. A. Schetz. "Direct Measurements of Skin Friction in Supersonic Combustion Flow Fields". Journal of Engineering for Gas Turbines and Power 115, nr 3 (1.07.1993): 507–14. http://dx.doi.org/10.1115/1.2906737.

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An experimental investigation was conducted to measure skin friction along the chamber walls of supersonic combustors. A direct force measurement device was used to measure simultaneously an axial and a transverse component of the small tangential shear force passing over a nonintrusive floating element. This measurement was made possible with a sensitive piezoresistive deflection sensing unit. The floating head is mounted to a stiff cantilever beam arrangement with deflection due to the flow on the order of 0.00254 mm (0.0001 in). This allowed the instrument to be a nonnulling type. A second gage was designed with active cooling of the floating sensor head to eliminate nonuniform temperature effects between the sensor head and the surrounding wall. The key to this device is the use of a quartz tube cantilever with piezoresistive strain gages bonded directly to its surface. A symmetric fluid flow was developed inside the quartz tube to provide cooling to the backside of the floating head. Tests showed that this flow did not influence the tangential force measurement. Measurements were made in three separate combustor test facilities. Tests at NASA Langley Research center consisted of a Mach 3.0 vitiated air flow with hydrogen fuel injection at Pt = 500 psia (3466 kPa) and Tt = 3000 R (1667 K). Two separate sets of tests were conducted at the General Applied Science Laboratory (GASL) in a scramjet combustor model with hydrogen fuel injection in vitiated air at Mach = 3.3, Pt = 800 psia (5510 kPa), and Tt = 4000 R (2222 K). Skin friction coefficients between 0.001–0.005 were measured dependent on the facility and measurement location. Analysis of the measurement uncertainties indicate an accuracy to within ± 10–15 percent of the streamwise component.

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Chen, Pei, Yulong Zhao, Bian Tian i Yiyao Li. "Design and fluid–structure interaction analysis of a micromachined cantilever‐based differential pressure flow sensor". Micro & Nano Letters 9, nr 10 (październik 2014): 650–54. http://dx.doi.org/10.1049/mnl.2014.0245.

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Sadegh Cheri, Mohammad, Hamid Latifi, Jalal Sadeghi, Mohammadreza Salehi Moghaddam, Hamidreza Shahraki i Hasan Hajghassem. "Real-time measurement of flow rate in microfluidic devices using a cantilever-based optofluidic sensor". Analyst 139, nr 2 (2014): 431–38. http://dx.doi.org/10.1039/c3an01588b.

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Liew Hui Fang, Rosemizi Abd Rahim, Muhammad Izuan Fahmi i Vmalen Kupusamy. "Modelling and Characterization Piezoelectric Transducer for Sound Wave Energy Harvesting". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 102, nr 2 (27.02.2023): 81–98. http://dx.doi.org/10.37934/arfmts.102.2.8198.

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Energy harvesting system is using ambient energy conversion in the environment. The environmental energy will be converted into usable electrical energy that can be used in controlling wireless electronic devices. The available mechanical vibration from the sound energy will then be converted to electrical energy by using a piezoelectric transducer. The size of the piezoelectric represents the surface area of the electrode on the piezoelectric model. A smaller size piezoelectric transducer is unable to produce a good vibration due to the smaller surface area. The bigger dimension of the piezoelectric model would be able to harvest more electrical energy output because the vibration from the bigger piezoelectric model which would able to produce more sound wave energy. The piezoelectric material Lead Zirconate Titanate (PZT-5H) vibration is focused on the resonance frequency at below 1 kHz with sound level decibel is between the range of 35-100 dB. This research is to concentrate on rectangular and trapezium-shaped cantilever. The trapezium shaped cantilever produces higher energy output due to its shape which has better in terms of stress and strain distribution. In addition, researchers have modelled and validated energy harvesters with different proof masses shapes. The improved piezoelectric vibrational energy harvester has a trapezoidal beam and an added triangular proof mass. The arrangement of the piezoelectric tested in parallel, series, combination series and parallel configuration to investigate the performance of the output power generated from the sound wave. The rectangular and trapezium shaped cantilever are resulted in a resonant frequency of 269.4 Hz and 269.88 Hz, respectively. The rectangular and trapezium shaped cantilever produced a maximum output voltage of 3.105 V and 3.635 V respectively. The piezoelectric output during the parallel array configuration, which is 5.636 V, 0.497 mA and 2.803 mW. The output power produced by parallel is 81 % higher than compare in series array configuration and 35.8 % higher than combination of series and parallel. Thus, the produced energy output 5 V would be able to apply at several low power supply applications such as mobile phones, power bank or wireless sensor networks (WSN).

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Trigona, Carlo, Salvatore Cerruto, Salvatore Graziani, Giovanna Di Pasquale i Antonino Pollicino. "Towards Environmentally Friendly Accelerometers Based on Bacterial Cellulose". Applied Sciences 11, nr 17 (27.08.2021): 7903. http://dx.doi.org/10.3390/app11177903.

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In this paper, an environmentally friendly inertial motion sensor is investigated, modelled, and characterized as an accelerometer. The sensor is obtained by using bacterial cellulose (BC) as a base biopolymer. BC is then impregnated with ionic liquids. Electrodes are realized by a conducting polymer, in a typical three-layer structure. The sensor works in a cantilever configuration and produces an open voltage signal as the result of a flexing deformation. A model is proposed for the transduction phenomenon. The composite mechano-electric transduction capability is exploited for realizing the accelerometer. Results of the chemical and transduction characterization of the accelerometer are reported. Finally, experimental evidence of the possible nature of the transduction phenomenon is given.

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Bian, Yixiang, Rongrong Liu i Shen Hui. "Fabrication of a polyvinylidene difluoride fiber with a metal core and its application as directional air flow sensor". Functional Materials Letters 09, nr 01 (luty 2016): 1650001. http://dx.doi.org/10.1142/s1793604716500016.

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We fabricated a sensitive air flow detector that mimic the sensing mechanism found at the tail of some insects. [see Y. Yang, A. Klein, H. Bleckmann and C. Liu, Appl. Phys. Lett. 99(2) (2011); J. J. Heys, T. Gedeon, B. C. Knott and Y. Kim, J. Biomech. 41(5), 977 (2008); J. Tao and X. Yu, Smart Mat. Struct. 21(11) (2012)]. Our bionic airflow sensor uses a polyvinylidene difluoride (PVDF) microfiber with a molybdenum core which we produced with the hot extrusion tensile method. The surface of the fiber is partially coated with conductive silver adhesive that serve as surface electrodes. A third electrode, the metal core is used to polarize polyvinylidene difluoride (PVDF) under the surface electrodes. The cantilever beam structure of the prepared symmetric electrodes of metal core piezoelectric fiber (SMPF) is used as the artificial hair airflow sensor. The surface electrodes are used to measure output voltage. Our theoretical and experimental results show that the SMPF responds fast to air flow changes, the output charge has an exponential correlation with airflow velocity and a cosine relation with the direction of airflow. Our bionic airflow sensor with directional sensing ability can also measure air flow amplitude. [see H. Droogendijk, R. G. P. Sanders and G. J. M. Krijnen, New J. Phys. 15 (2013)]. By using two surface electrodes, our sensing circuit further improves sensitivity.

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Goeckeritz, Jeremy, Gary Aden i Ami Chand. "Nanometer Thermal Conductivity Mapping Using Laser-based Scanning Thermal Microscopy". MRS Proceedings 1754 (2015): 81–86. http://dx.doi.org/10.1557/opl.2015.256.

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ABSTRACTA new measurement technique using a cantilever probe with an integrated thermal sensor is investigated for measuring thermal conductivity at the nanometer scale. The probe is used in a configuration wherein the laser from an atomic force microscope (AFM) heats the tip of the probe above ambient temperature. Heat is transferred from the probe to a sample based on the thermal conductivity of the sample. The heat flow creates a temperature change, as small as 0.01 °C, which is detected by the thermal sensor. The measurement technique presented offers a simple and effective method for mapping the thermal conductivity of a number of materials. We explore the ability of the technique to map silicon oxide on silicon, carbon fibers and gold nanoparticles. Analysis shows that the technique can be used to produce images with a thermal resolution surpassing 25 nm.

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Khan, Umar, Adnan, Naveed Ahmed, Syed Tauseef Mohyud-Din, Yu-Ming Chu, Ilyas Khan i Kottakkaran Sooppy Nisar. "γ-Nanofluid Thermal Transport between Parallel Plates Suspended by Micro-Cantilever Sensor by Incorporating the Effective Prandtl Model: Applications to Biological and Medical Sciences". Molecules 25, nr 8 (13.04.2020): 1777. http://dx.doi.org/10.3390/molecules25081777.

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The flow of nanofluid between infinite parallel plates suspended by micro-cantilever sensors is significant. The analysis of such flows is a rich research area due to the variety of applications it has in chemical, biological and medical sciences. Micro-cantilever sensors play a significant role in accurately sensing different diseases, and they can be used to detect many hazardous and bio-warfare agents. Therefore, flow water and ethylene glycol (EG) composed by γ-nanoparticles is used. Firstly, the governing nanofluid model is transformed into two self-similar nanofluid models on the basis of their effective models. Then, a numerical method is adopted for solution purposes, and both the nanofluid models are solved. To enhance the heat transfer characteristics of the models, the effective Prandtl model is ingrained in the energy equation. The velocity F’(η) decreases with respect to the suction of the fluid, because more fluid particles drags on the surface for suction, leading to an abrupt decrement in F’(η). The velocity F’(η) increases for injection of the fluid from the upper end, and therefore the momentum boundary layer region is prolonged. A high volume fraction factor is responsible for the denser characteristics of the nanofluids, due to which the fluids become more viscous, and the velocity F’(η) drops abruptly, with the magnetic parameters favoring velocity F’(η). An increase in temperature β ( η ) of Al2O3-H2O and γAl2O3-C2H6O2 nanofluids was reported at higher fraction factors with permeable parameter effects. Finally, a comparative analysis is presented by restricting the flow parameters, which shows the reliability of the study.

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Liu, Min, Hui Xia i Guoqiang Liu. "Experimental and numerical study of underwater piezoelectric generator based on Vortex-induced Vibration". Engineering Research Express 3, nr 4 (1.12.2021): 045056. http://dx.doi.org/10.1088/2631-8695/ac33f0.

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Abstract Efficient energy use to be transformed into electricity for small power devices has drawn increasing attention. A piezoelectric energy harvester is proposed to convert flow energy underwater to electrical energy. The harvester consists of the connecting device, springs, base, bluff body, piezoelectric cantilever beam and displacement sensor. The output voltage is derived from the flow-solid-electric coupling equations, including a nonlinear van der Pol equation, a linear equation of structural vibration and a piezoelectric equivalent circuit. Vibration response and output performance are obtained based on the finite central difference method. The theoretical results show that the vibration frequency, amplitude and average power increase with the limited water velocity. Furthermore, it is demonstrated that a proper selection of structure mass and load resistance can improve average harvested power for the available water velocity. Finally, the experimental prototype is fabricated to test piezoelectric generator performance at different water speeds, which shows good agreement with the theoretical results. This work provides a significant guide for the underwater use of piezoelectric energy harvesters.

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SADER, JOHN E., THOMAS P. BURG i SCOTT R. MANALIS. "Energy dissipation in microfluidic beam resonators". Journal of Fluid Mechanics 650 (22.03.2010): 215–50. http://dx.doi.org/10.1017/s0022112009993521.

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The fluid–structure interaction of resonating microcantilevers immersed in fluid has been widely studied and is a cornerstone in nanomechanical sensor development. In many applications, fluid damping imposes severe limitations by strongly degrading the signal-to-noise ratio of measurements. Recently, Burg et al. (Nature, vol. 446, 2007, pp. 1066–1069) proposed an alternative type of microcantilever device whereby a microfluidic channel was embedded inside the cantilever with vacuum outside. Remarkably, it was observed that energy dissipation in these systems was almost identical when air or liquid was passed through the channel and was 4 orders of magnitude lower than that in conventional microcantilever systems. Here, we study the fluid dynamics of these devices and present a rigorous theoretical model corroborated by experimental measurements to explain these observations. In so doing, we elucidate the dominant physical mechanisms giving rise to the unique features of these devices. Significantly, it is found that energy dissipation is not a monotonic function of fluid viscosity, but exhibits oscillatory behaviour, as fluid viscosity is increased/decreased. In the regime of low viscosity, inertia dominates the fluid motion inside the cantilever, resulting in thin viscous boundary layers – this leads to an increase in energy dissipation with increasing viscosity. In the high-viscosity regime, the boundary layers on all surfaces merge, leading to a decrease in dissipation with increasing viscosity. Effects of fluid compressibility also become significant in this latter regime and lead to rich flow behaviour. A direct consequence of these findings is that miniaturization does not necessarily result in degradation in the quality factor, which may indeed be enhanced. This highly desirable feature is unprecedented in current nanomechanical devices and permits direct miniaturization to enhance sensitivity to environmental changes, such as mass variations, in liquid.

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JUNG, MI-YOUNG, S. S. CHOI, C. J. KANG i Y. KUK. "FABRICATION OF BIMETALLIC CANTILEVERS AND ITS CHARACTERIZATION". Surface Review and Letters 06, nr 06 (grudzień 1999): 1195–99. http://dx.doi.org/10.1142/s0218625x99001335.

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Most SPM sensors utilize a current-imaging technique or force-imaging techniques that allow imaging nanoscale topography of the surface using a nanoscale tip on cantilever. In this work, the various cantilevers were microfabricated with a SiO 2 thin film or a Si 3 N 4 thin film. Thermal imaging technique using microfabricated Si 3 N 4 cantilevers has been investigated. The temperature change and heat flow across the fabricated bimetallic cantilever will create angular bending of the bimetallic metal-coated lever. Its thermal response was qualitatively examined during an endothermic chemical reaction using optical deflection methods. The chemical used in this experiment is the tetradecanol CH 3( CH 2)13 OH , with a known theoretical phase transition temperature of ~ 313 K.

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Sheleg, V. K., Ma Min i M. A. Belotserkovsky. "Production Technology and Damping Properties of Aerated Polymer Coatings". Science & Technique 20, nr 5 (7.10.2021): 375–82. http://dx.doi.org/10.21122/2227-1031-2021-20-5-375-382.

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The process of obtaining aerated (filled with air bubbles) polymer coatings has been developed and investigated by the method of flame spraying with an assessment of their ability to damp vibrations. A technology for the controlled formation of aerated polymer coatings has been developed while using the capabilities of the ОИМ (OIM) 050 polymer thermal atomizer design which consists in providing a concurrent air flow between the flame torch and the jet of powder material. The experiments have been carried out with such thermoplastic polymers as polyethylene terephthalate, high pressure polyethylene, ultra high molecular weight polyethylene, polyamide. It has been found that the aeration coefficient grows almost in direct proportion with an increase in the amount of air in the concurrent flow for all investigated polymer coatings. It is noted that the aeration process is influenced by the rheological properties of liquid polymers, or rather, the value of the polymer melt flow rate. The limiting values of air in the concurrent flow have been determined, which make it possible not to reduce the adhesion of polymer coatings to steel substrates by less than 6 MPa and not to decrease their hardness by more than 25–30 %. Studies of the damping properties of samples with polymer coatings have been carried out on a stand, the kinematic diagram of which is based on loading the free end of a cantilever sample, abrupt removal of the load and registration of free damped oscillations by an induction-type contactless sensor connected to a computer. It is shown that the use of aeration when forming noise-absorbing coatings on steel samples can increase their logarithmic damping decrement by 18–26 %.

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Rasani, Mohammad Rasidi, Ji Yuan Tu i Nik Abdullah Nik Mohamed. "Numerical Investigation of Flow-Induced Vibration of a Cantilever Beam for a Piezoelectric Energy Harvester". Applied Mechanics and Materials 225 (listopad 2012): 97–102. http://dx.doi.org/10.4028/www.scientific.net/amm.225.97.

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Flexible cantilever beams in channel flow loses its stability through a flutter mechanism at sufficiently high Reynolds number. This sustained transfer of flow work to cantilever beam oscillation could be extracted to generate electrical power, which may be utilized to power wireless sensors for structural health monitoring or supply additional power in unmanned or micro air vehicles. Such flexible beam system is known to exhibit some form of hysteresis, with super- and sub-critical velocities for onset of flutter, which may not be captured by current potential flow modeling. We present numerical simulation of a viscous, Navier-Stokes solver coupled to a cantilever beam, to capture this flutter velocity hysteresis. Numerical result under a linearly varying flow velocity shows an approximately 11% hysteresis, suggesting potential of present model for identifying more accurate boundaries of beam flutter. The prediction of cantilevered piezoelectric beam response under varying or unsteady flow velocities is necessary for reliable design of energy harvesting devices and warrants further experimental investigations.

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Gurumurthy, C. K., J. Jiao, L. G. Norris, C. Y. Hui i E. J. Kramer. "A Thermo-Mechanical Approach for Fatigue Testing of Polymer Bimaterial Interfaces". Journal of Electronic Packaging 120, nr 4 (1.12.1998): 372–78. http://dx.doi.org/10.1115/1.2792649.

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We have developed a new technique that uses a noncontact fiber optic displacement sensor to investigate the crack growth along polymer interfaces under thermal fatigue conditions. This technique has been used to test the underfill/passivation interface of a direct chip attach (DCA) assembly, the thermal fatigue driven delamination of which is a major cause for failure of DCA assemblies. The sample is prepared as a multilayered cantilever beam by capillary flow of the underfill over a polyimide coated metallic beam. During thermal cycling the crack growth along the interface from the free end changes the displacement of this end of the beam and we measure this displacement at the lowest temperature in each thermal cycle. The change in beam displacement is converted into crack growth knowing the geometry of the specimen. The crack growth rate depends on the maximum difference in the strain energy release rate of the crack in each cycle and the mechanical phase angle. This paper outlines the theoretical basis of the technique and provides initial results obtained for a variety of underfills dispensed over a commercial (PMDA/ODA) polyimide. The technique was validated by comparing the crack growth measured by displacement changes with direct optical microscopy measurements of the crack length.

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Jeong, Cheol-Su, Gunwoo Kim, Inwon Lee i Sangrok Jin. "Empirical Modeling of 2-Degree-of-Freedom Azimuth Underwater Thruster Using a Signal Compression Method". Applied Sciences 11, nr 8 (14.04.2021): 3517. http://dx.doi.org/10.3390/app11083517.

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This paper presents an empirical modeling of a 2-Degree-of-Freedom (DoF) azimuth thruster using the signal compression method. The thruster has a gimbal mechanism with two servo motors and generates thrust in arbitrary directions. This mechanism can reduce the number of thrusters in an underwater robot and contribute to compact design. When an underwater robot is controlled with azimuth thrusters, the influence from the rotational motion of the thruster has to be considered, and a dynamic model of the azimuth thruster is needed. It is difficult to derive an analytical model because the system model depends on complicated fluid dynamics. In this study, empirical models of force and moment for rotational motion were derived for practical use through frequency analysis. A signal compression method can effectively extract the system model in the frequency domain from just the mechanically constrained frequency response. Experiments were carried out using a force/torque sensor that was connected to a cantilever in a water tank. The system model was analyzed with Bode plots, and the model coefficients were derived through curve fitting. The derived model was verified by a validation experiment.

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Bai, Jie, Pingjuan Niu, Shinan Cao i Qiang Liu. "The Adhesive Force Measurement between Single μLED and Substrate Based on Atomic Force Microscope". Applied Sciences 12, nr 19 (21.09.2022): 9480. http://dx.doi.org/10.3390/app12199480.

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Compared with traditional liquid crystal and organic light emitting diode (OLED), micro light emitting diode (μLED) has advantages in brightness, power consumption, and response speed. It has important applications in microelectronics, micro-electro-mechanical systems, biomedicine, and sensor systems. μLED massive transfer method plays an important role in these applications. However, the existing μLED massive transfer method is faced with the problem of low yield. To better transfer the μLED, the force value detached from the substrate needs to be measured. Atomic force microscope (AFM) was used to measure the force of a single μLED when it detached from the substrate. The μLED was glued to the front of the cantilever. When a single μLED was in contact with or detached from the Polydimethylsiloxane (PDMS), the maximum pull-off force can be obtained. The force at different peel speeds and preload was measured, and the experimental results show that the separation force between a single μLED and PDMS substrate is not only related to the peel speeds, but also related to the preload. The force values under different peel speeds and preload were measured to lay a theoretical foundation for better design of μLED massive transfer system.

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Zelinger, Z., P. Janda, J. Suchánek, M. Dostál, P. Kubát, V. Nevrlý, P. Bitala i S. Civiš. "Silicon micro-levers and a multilayer graphene membrane studied via laser photoacoustic detection". Journal of Sensors and Sensor Systems 4, nr 1 (5.03.2015): 103–9. http://dx.doi.org/10.5194/jsss-4-103-2015.

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Abstract. Laser photoacoustic spectroscopy (PAS) is a method that utilizes the sensing of the pressure waves that emerge upon the absorption of radiation by absorbing species. The use of the conventional electret microphone as a pressure sensor has already reached its limit, and a new type of microphone – an optical microphone – has been suggested to increase the sensitivity of this method. The movement of a micro-lever or a membrane is sensed via a reflected beam of light, which falls onto a position-sensing detector. The use of one micro-lever as a pressure sensor in the form of a silicon cantilever has already enhanced the sensitivity of laser PAS. Herein, we test two types of home-made sensing elements – four coupled silicon micro-levers and a multilayer graphene membrane – which have the potential to enhance this sensitivity further. Graphene sheets possess outstanding electromechanical properties and demonstrate impressive sensitivity as mass detectors. Their mechanical properties make them suitable for use as micro-/nano-levers or membranes, which could function as extremely sensitive pressure sensors. Graphene sheets were prepared from multilayer graphene through the micromechanical cleavage of basal plane highly ordered pyrolytic graphite. Multilayer graphene sheets (thickness ∼102 nm) were then mounted on an additional glass window in a cuvette for PAS. The movements of the sheets induced by acoustic waves were measured using an He–Ne laser beam reflected from the sheets onto a quadrant detector. A discretely tunable CO2 laser was used as the source of radiation energy for the laser PAS experiments. Sensitivity testing of the investigated sensing elements was performed with the aid of concentration standards and a mixing arrangement in a flow regime. The combination of sensitive microphones and micromechanical/nanomechanical elements with laser techniques offers a method for the study and development of new, reliable and highly sensitive chemical sensing systems. To our knowledge, we have produced the first demonstration of the feasibility of using four coupled silicon micro-levers and graphene membranes in an optical microphone for PAS. Although the sensitivity thus far remains inferior to that of the commercial electret microphone (with an S / N ratio that is 5 times lower), further improvement is expected to be achieved by adjusting the micro-levers and membrane elements, the photoacoustic system and the position detector.

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Yang, Yongming, Chunfeng Yu, Yuanchao Wang, Nan Hua i Haipeng Kuang. "Imaging Attitude Control and Image Motion Compensation Residual Analysis Based on a Three-Axis Inertially Stabilized Platform". Applied Sciences 11, nr 13 (24.06.2021): 5856. http://dx.doi.org/10.3390/app11135856.

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The airborne area camera has received broad application in aerial reconnaissance, land resource surveying, environmental monitoring, photogrammetry mapping, and natural disaster information acquisition. A three-axis, inertially stabilized platform with a large rotation range for the roll axis is designed, which is based on the cantilever structure, in order to realize a large-angle sweep imaging function for airborne area cameras. An image attitude control algorithm in the inertial space is proposed, which can regulate the line of sight (LOS) as well as the image orientation. The area camera image motion calculation model and image motion compensation residual computing method are proposed, utilizing space position and velocity vector transformation mathematics and derivations. The variation of linear velocity of the image motion in the sensor frame is analyzed, and the changing laws of the maximum deviation of image motion with the image attitude are studied. Flight tests imply that the vertical imaging technique correctly regulates the LOS along the local geodetic vertical. The along-flight overlap rate is greater than 65%, which meets the stereo mapping requirement. The sweep imaging technique considerably enlarges the cross-flight angle of view. The LOS and image orientation during sweep imaging are correctly controlled, and gap-free coverage of the survey area is maintained. The image’s azimuth or roll deviation is less than 0.1°, and the image pitch deviation is less than 0.35°. The quality of the test images is superior. Black and white line pairs for evaluation can be clearly distinguished. The image’s motion is well compensated, and the image motion compensation residual is well constrained. These verify the validity of the proposed imaging technique and the image motion analysis model.

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