Artykuły w czasopismach: „Piezoresistive transducer”

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Pereira, Ricardo dos Santos, i Carlos Alberto Cima. "Thermal Compensation Method for Piezoresistive Pressure Transducer". IEEE Transactions on Instrumentation and Measurement 70 (2021): 1–7. http://dx.doi.org/10.1109/tim.2021.3092789.

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Stiefvater, Jason, Yuhong Kang, Albrey de Clerck, Shuo Mao, Noah Jones, Josh Deem, Alfred Wicks, Hang Ruan i Wing Ng. "Dual-Use Strain Sensors for Acoustic Emission and Quasi-Static Bending Measurements". Sensors 24, nr 5 (2.03.2024): 1637. http://dx.doi.org/10.3390/s24051637.

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In this paper, a MEMS piezoresistive ultrathin silicon membrane-based strain sensor is presented. The sensor’s ability to capture an acoustic emission signal is demonstrated using a Hsu–Nielsen source, and shows comparable frequency content to a commercial piezoceramic ultrasonic transducer. To the authors’ knowledge, this makes the developed sensor the first known piezoresistive strain sensor which is capable of recording low-energy acoustic emissions. The improvements to the nondestructive evaluation and structural health monitoring arise from the sensor’s low minimum detectable strain and wide-frequency bandwidth, which are generated from the improved fabrication process that permits crystalline semiconductor membranes and advanced polymers to be co-processed, thus enabling a dual-use application of both acoustic emission and static strain sensing. The sensor’s ability to document quasi-static bending is also demonstrated and compared with an ultrasonic transducer, which provides no significant response. This dual-use application is proposed to effectively combine the uses of both strain and ultrasonic transducer sensor types within one sensor, making it a novel and useful method for nondestructive evaluations. The potential benefits include an enhanced sensitivity, a reduced sensor size, a lower cost, and a reduced instrumentation complexity.

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Rollins, Kyle M., J. Dusty Lane, Emily Dibb, Scott A. Ashford i A. Gray Mullins. "Pore Pressure Measurement in Blast-Induced Liquefaction Experiments". Transportation Research Record: Journal of the Transportation Research Board 1936, nr 1 (styczeń 2005): 210–20. http://dx.doi.org/10.1177/0361198105193600124.

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Blast-induced liquefaction experiments have been conducted at a number of test sites to evaluate lateral foundation resistance and soil improvement techniques. Tests can be constructed at full scale without waiting for an earthquake. In this extreme environment, pore pressure transducers must survive transient blast pressures of 41.4 MPa (6,000 psi) yet have enough resolution to measure residual pore pressures of ±0.69 kPa (0.1 psi). Three transducer types were evaluated under these demanding conditions, and the piezoresistive transducer was found to be the most robust. These sensors were repeatedly subjected to extreme blast pressures and vibration, but they still provided accurate time histories of residual pore pressure. Although these piezometers are more expensive than other types, installation techniques allowed them to be recovered and reused in subsequent tests and thus reduced overall costs. These pore pressure sensors make it possible to define the extent of the liquefied zone during blast liquefaction experiments and to understand the soil behavior during cyclic loading of deep foundations.

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Bayram, Ferhat, Durga Gajula, Digangana Khan i Goutam Koley. "Investigation of AlGaN/GaN HFET and VO2 Thin Film Based Deflection Transducers Embedded in GaN Microcantilevers". Micromachines 11, nr 9 (20.09.2020): 875. http://dx.doi.org/10.3390/mi11090875.

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The static and dynamic deflection transducing performances of piezotransistive AlGaN/GaN heterojunction field effect transistors (HFET) and piezoresistive VO2 thin films, fabricated on GaN microcantilevers of similar dimensions, were investigated. Deflection sensitivities were tuned with the gate bias and operating temperature for embedded AlGaN/GaN HFET and VO2 thin film transducers, respectively. The GaN microcantilevers were excited with a piezoactuator in their linear and nonlinear oscillation regions of the fundamental oscillatory mode. In the linear regime, the maximum deflection sensitivity of piezotransistive AlGaN/GaN HFET reached up to a 0.5% change in applied drain voltage, while the responsivity of the piezoresistive VO2 thin film based deflection transducer reached a maximum value of 0.36% change in applied drain current. The effects of the gate bias and the operation temperature on nonlinear behaviors of the microcantilevers were also experimentally examined. Static deflection sensitivity measurements demonstrated a large change of 16% in drain-source resistance of the AlGaN/GaN HFET, and a similarly high 11% change in drain-source resistance in the VO2 thin film, corresponding to a 10 μm downward step bending of the cantilever free end.

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Almassri, Ahmed M., W. Z. Wan Hasan, S. A. Ahmad, A. J. Ishak, A. M. Ghazali, D. N. Talib i Chikamune Wada. "Pressure Sensor: State of the Art, Design, and Application for Robotic Hand". Journal of Sensors 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/846487.

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We survey the state of the art in a variety of force sensors for designing and application of robotic hand. Most of the force sensors are examined based on tactile sensing. For a decade, many papers have widely discussed various sensor technologies and transducer methods which are based on microelectromechanical system (MEMS) and silicon used for improving the accuracy and performance measurement of tactile sensing capabilities especially for robotic hand applications. We found that transducers and materials such as piezoresistive and polymer, respectively, are used in order to improve the sensing sensitivity for grasping mechanisms in future. This predicted growth in such applications will explode into high risk tasks which requires very precise purposes. It shows considerable potential and significant levels of research attention.

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Søndergård, Ole, i Peter Gravesen. "A new piezoresistive pressure transducer principle with improvements in media compatibility". Journal of Micromechanics and Microengineering 6, nr 1 (1.03.1996): 105–7. http://dx.doi.org/10.1088/0960-1317/6/1/025.

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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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Tong, Zhao Jing, Xiu Hua Shi, Xiang Dang Du, Sheng Wu Wang i Tian Peng He. "Temperature Compensation System of Diesel Engine Piezoresistive Pressure Transducer Based on Neural Networks and LabVIEW". Applied Mechanics and Materials 241-244 (grudzień 2012): 833–36. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.833.

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The work presented in this paper focuses on the output of temperature compensation system of diesel engine piezoresistive pressure transducer, it is nonlinear and influenced easily by environmental temperature. The paper studied the method of using improved neural network algorithm based on LabVIEW and MATLAB to increase the precision and efficiency of pressure detection. In order to eliminate the temperature influence, this paper proposed the method of using improved back propagation neural network on LabVIEW platform, which realized the communication between LabVIEW and MATLAB. The experimental results show that, with the using of Matlab Script node, the system benefits from the huge computing power of MATLAB to train the network based on the static calibration data of transducer, and makes temperature compensation more efficient and accurate.

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Froemel, Joerg, Gildas Diguet i Masanori Muroyama. "Micromechanical Force Sensor Using the Stress–Impedance Effect of Soft Magnetic FeCuNbSiB". Sensors 21, nr 22 (15.11.2021): 7578. http://dx.doi.org/10.3390/s21227578.

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By using the stress–impedance (SI) effect of a soft magnetic amorphous FeCuNbSiB alloy, a micromachined force sensor was fabricated and characterized. The alloy was used as a sputtered thin film of 500 nm thickness. To clarify the SI effect in the used material as a thin film, its magnetic and mechanical properties were first investigated. The stress dependence of the magnetic permeability was shown to be caused by the used transducer effect. The sputtered thin film also exhibited a large yield strength of 983 GPa. Even though the fabrication technology for the device is very simple, characterization revealed a gauge factor (GF) of 756, which is several times larger than that achieved with conventional transducer effects, such as the piezoresistive effect. The fabricated device shows great application potential as a tactile sensor.

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Chartrand, D. A., T. H. Ye, J. M. Maarek i H. K. Chang. "Measurement of pleural pressure at low and high frequencies in normal rabbits". Journal of Applied Physiology 63, nr 3 (1.09.1987): 1142–46. http://dx.doi.org/10.1152/jappl.1987.63.3.1142.

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In eight tracheotomized adult rabbits placed in the supine position, we employed a catheter-tip piezoresistive pressure transducer to measure esophageal pressure (Pes) and assessed the validity of taking the changes in Pes to be the changes in pleural pressure (Ppl). We applied an occlusion test in which the tracheal cannula was occluded during either spontaneous inspiratory efforts or body surface oscillations ranging from 3 to 50 Hz. The relationship between Pes and airway opening pressure (Pao) was recorded. In all instances, the changes in Pes and Pao were virtually identical in both amplitude and phase. We conclude that, as evaluated by the occlusion test, a catheter-tip pressure transducer placed in the esophagus of rabbits can give adequate estimation of local pleural changes up to at least 50 Hz.

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Szczerba, Zygmunt, Piotr Szczerba i Kamil Szczerba. "Sensitivity of Piezoresistive Pressure Sensors to Acceleration". Energies 15, nr 2 (11.01.2022): 493. http://dx.doi.org/10.3390/en15020493.

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The article presents the negative aspects of the influence of static and dynamic acceleration on the accuracy of pressure measurement for a selected type of transmitter. The influence of static accelerations from catalog notes was shown and compared with the tests results for a few selected sensors. The results of research on the influence of dynamic acceleration for various types of its variability for selected converters are presented. Moreover, a method of measurement patented by the authors that uses a complex transducer is shown. The method allows for more accurate measurements on moving objects. The tests were performed based on the proposed method. The obtained results of the influence of acceleration on the classical sensor as well as the construction using the proposed method are shown. The paper presents approximate pressure measurement errors resulting from the influence of acceleration. For example, errors in measuring the speed of an airplane may occur without the proposed method. The last part of the article presents a unique design dedicated to a multi-point pressure measurement system, which uses the presented method of eliminating the influence of accelerations on the pressure measurement.

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Thuau, Damien, Katherine Begley, Rishat Dilmurat, Abduleziz Ablat, Guillaume Wantz, Cédric Ayela i Mamatimin Abbas. "Exploring the Critical Thickness of Organic Semiconductor Layer for Enhanced Piezoresistive Sensitivity in Field-Effect Transistor Sensors". Materials 13, nr 7 (30.03.2020): 1583. http://dx.doi.org/10.3390/ma13071583.

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Organic semiconductors (OSCs) are promising transducer materials when applied in organic field-effect transistors (OFETs) taking advantage of their electrical properties which highly depend on the morphology of the semiconducting film. In this work, the effects of OSC thickness (ranging from 5 to 15 nm) on the piezoresistive sensitivity of a high-performance p-type organic semiconductor, namely dinaphtho [2,3-b:2,3-f] thieno [3,2–b] thiophene (DNTT), were investigated. Critical thickness of 6 nm thin film DNTT, thickness corresponding to the appearance of charge carrier percolation paths in the material, was demonstrated to be highly sensitive to mechanical strain. Gauge factors (GFs) of 42 ± 5 and −31 ± 6 were measured from the variation of output currents of 6 nm thick DNTT-based OFETs engineered on top of polymer cantilevers in response to compressive and tensile strain, respectively. The relationship between the morphologies of the different thin films and their corresponding piezoresistive sensitivities was discussed.

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Rizal, Muhammad, Jaharah A. Ghani i Amir Zaki Mubarak. "Design and Development of a Tri-Axial Turning Dynamometer Utilizing Cross-Beam Type Force Transducer for Fine-Turning Cutting Force Measurement". Sensors 22, nr 22 (12.11.2022): 8751. http://dx.doi.org/10.3390/s22228751.

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The main focus of this work was the design and development of a cross-beam force transducer for use in the construction of a tri-axial dynamometer. This dynamometer would be able to measure the cutting force along all three axes simultaneously during turning operations. The force transducer was built on the concept of the Maltese cross-beam, but it had been modified and improved so that it had a higher sensitivity and reduced the amount of interference error or cross-talk error that it produced. An investigation into the distribution of strain, as well as the determination of sensor locations within the transducer construction was carried out by means of finite element analysis. In order to develop a prototype of a turning dynamometer, a number of piezoresistive strain gauges were utilized in the transducer. In order to determine sensitivity, linearity, hysteresis, and repeatability, calibration tests were performed in three directions that were perpendicular to one another. To investigate the dynamic properties and capabilities of the dynamometer for use in turning applications, both modal analysis and actual turning tests were performed. The results of the experiments demonstrated that the newly developed turning dynamometer is a realistic approach for measuring cutting force in machining without reliability and accuracy.

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Spender, R. R., B. M. Fleischer, P. W. Barth i J. B. Angell. "A theoretical study of transducer noise in piezoresistive and capacitive silicon pressure sensors". IEEE Transactions on Electron Devices 35, nr 8 (sierpień 1988): 1289–98. http://dx.doi.org/10.1109/16.2550.

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Gossweiler, C. R., P. Kupferschmied i G. Gyarmathy. "On Fast-Response Probes: Part 1—Technology, Calibration, and Application to Turbomachinery". Journal of Turbomachinery 117, nr 4 (1.10.1995): 611–17. http://dx.doi.org/10.1115/1.2836579.

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A system for fast-response probe measurements in turbomachine flows has been developed and tested. The system has been designed for 40 kHz bandwidth and used with various in-house built probes accommodating up to four piezoresistive pressure transducers. The present generation of probes works accurately up to several bar pressure and 120°C temperature. The probes were found to be quite robust. The use of a miniature pressure transducer placed in the head of a probe showed that a precise packaging technique and a careful compensation of errors can considerably improve the accuracy of the pressure measurement. Methods for aerodynamic probe calibration and off-line data evaluation are briefly presented. These aimed, e.g., in the case of a four-hole probe, at measuring the velocity fluctuations as characterized by yaw, pitch, total pressure, and static pressure and at deriving mean values and spectral or turbulence parameters. Applications of the measuring system to turbomachinery flow in a radial compressor and to a turbulent pipe flow demonstrate the performance of the measuring system.

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Kayed, Mohammed O., Amr Adel Balbola i Walied A. Moussa. "A New Temperature Transducer for Local Temperature Compensation for Piezoresistive 3-D Stress Sensors". IEEE/ASME Transactions on Mechatronics 24, nr 2 (kwiecień 2019): 832–40. http://dx.doi.org/10.1109/tmech.2019.2891069.

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Haus, Jan Niklas, Walter Lang, Thomas Roloff, Liv Rittmeier, Sarah Bornemann, Michael Sinapius i Andreas Dietzel. "MEMS Vibrometer for Structural Health Monitoring Using Guided Ultrasonic Waves". Sensors 22, nr 14 (19.07.2022): 5368. http://dx.doi.org/10.3390/s22145368.

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Structural health monitoring of lightweight constructions made of composite materials can be performed using guided ultrasonic waves. If modern fiber metal laminates are used, this requires integrated sensors that can record the inner displacement oscillations caused by the propagating guided ultrasonic waves. Therefore, we developed a robust MEMS vibrometer that can be integrated while maintaining the structural and functional compliance of the laminate. This vibrometer is directly sensitive to the high-frequency displacements from structure-borne ultrasound when excited in a frequency range between its first and second eigenfrequency. The vibrometer is mostly realized by processes earlier developed for a pressure sensor but with additional femtosecond laser ablation and encapsulation. The piezoresistive transducer, made from silicon, is encapsulated between top and bottom glass lids. The eigenfrequencies are experimentally determined using an optical micro vibrometer setup. The MEMS vibrometer functionality and usability for structural health monitoring are demonstrated on a customized test rig by recording application-relevant guided ultrasonic wave packages with a central frequency of 100 kHz at a distance of 0.2 m from the exciting ultrasound transducer.

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Wang, Luheng, i Yanling Li. "A Review for Conductive Polymer Piezoresistive Composites and a Development of a Compliant Pressure Transducer". IEEE Transactions on Instrumentation and Measurement 62, nr 2 (luty 2013): 495–502. http://dx.doi.org/10.1109/tim.2012.2215160.

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Krestovnikov, Konstantin, Aleksei Erashov i Аleksandr Bykov. "Development of circuit solution and design of capacitive pressure sensor array for applied robotics". Robotics and Technical Cybernetics 8, nr 4 (30.12.2020): 296–307. http://dx.doi.org/10.31776/rtcj.8406.

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This paper presents development of pressure sensor array with capacitance-type unit sensors, with scalable number of cells. Different assemblies of unit pressure sensors and their arrays were considered, their characteristics and fabrication methods were investigated. The structure of primary pressure transducer (PPT) array was presented; its operating principle of array was illustrated, calculated reference ratios were derived. The interface circuit, allowing to transform the changes in the primary transducer capacitance into voltage level variations, was proposed. A prototype sensor was implemented; the dependency of output signal power from the applied force was empirically obtained. In the range under 30 N it exhibited a linear pattern. The sensitivity of the array cells to the applied pressure is in the range 134.56..160.35. The measured drift of the output signals from the array cells after 10,000 loading cycles was 1.39%. For developed prototype of the pressure sensor array, based on the experimental data, the average signal-to-noise ratio over the cells was calculated, and equaled 63.47 dB. The proposed prototype was fabricated of easily available materials. It is relatively inexpensive and requires no fine-tuning of each individual cell. Capacitance-type operation type, compared to piezoresistive one, ensures greater stability of the output signal. The scalability and adjustability of cell parameters are achieved with layered sensor structure. The pressure sensor array, presented in this paper, can be utilized in various robotic systems.

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Li, Liang, Lei, Hong, Li, Li, Ghaffar, Li i Xiong. "Quantitative Analysis of Piezoresistive Characteristic Based on a P-type 4H-SiC Epitaxial Layer". Micromachines 10, nr 10 (20.09.2019): 629. http://dx.doi.org/10.3390/mi10100629.

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In this work, the piezoresistive properties of heavily doped p-type 4H-SiC at room temperature were investigated innovatively. It was verified by a field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and laser Raman spectroscopy (LRS) that the crystal quality of the epitaxial layer was good. The doping concentration and thickness of the epitaxial layer were measured by secondary ion mass spectrometry (SIMS) to be ~1.12 × 1019 cm−3 and ~1.1 μm, respectively. The 4H-SiC cantilever beam along crystal orientation was fabricated, and the fixed end of the cantilever beam was integrated with longitudinal and transverse p-type 4H-SiC piezoresistors. A good ohmic contact was formed between Ni/Ti/Al/Au and a p-type 4H-SiC piezoresistor under nitrogen environment annealing at 1050 °C for 5 min. The free end of the cantilever beam was forced to cause strain on the p-type 4H-SiC piezoresistor, and then the resistances were measured by a high precision multimeter. The experimental results illustrated that longitudinal and transverse gauge factors (GFs) of the p-type 4H-SiC piezoresistors were 26.7 and −21.5, respectively, within the strain range of 0–336με. In order to further verify the electro-mechanical coupling effect of p-type 4H-SiC, the piezoresistors on the beam were connected to the Wheatstone full-bridge circuit and the output changes were observed under cyclic loading of 0–0.5 N. The measuring results revealed that the transducer based on the 4H-SiC piezoresistive effect exhibited good linearity and hysteresis, which confirmed that p-type 4H-SiC has the potential for pressure or acceleration sensing applications.

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Kumar, Shashi, Gaddiella Diengdoh Ropmay, Pradeep Kumar Rathore, Peesapati Rangababu i Jamil Akhtar. "Fabrication and testing of PMOS current mirror-integrated MEMS pressure transducer". Sensor Review 40, nr 2 (23.11.2019): 141–51. http://dx.doi.org/10.1108/sr-07-2019-0182.

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Purpose This paper aims to describe the fabrication, packaging and testing of a resistive loaded p-channel metal-oxide-semiconductor field-effect transistor-based (MOSFET-based) current mirror-integrated pressure transducer. Design/methodology/approach Using the concept of piezoresistive effect in a MOSFET, three identical p-channel MOSFETs connected in current mirror configuration have been designed and fabricated using the standard polysilicon gate process and microelectromechanical system (MEMS) techniques for pressure sensing application. The channel length and width of the p-channel MOSFETs are 100 µm and 500 µm, respectively. The MOSFET M1 of the current mirror is the reference transistor that acts as the constant current source. MOSFETs M2 and M3 are the pressure-sensing transistors embedded on the diaphragm near the mid of fixed edge and at the center of the square diaphragm, respectively, to experience both the tensile and compressive stress developed due to externally applied input pressure. A flexible square diaphragm having a length of approximately 1,000 µm and thickness of 50 µm has been realized using deep-reactive ion etching of silicon on the backside of the wafer. Then, the fabricated sensor chip has been diced and mounted on a TO8 header for the testing with pressure. Findings The experimental result of the pressure sensor chip shows a sensitivity of approximately 0.2162 mV/psi (31.35 mV/MPa) for an input pressure of 0-100 psi. The output response shows a good linearity and very low-pressure hysteresis. In addition, the pressure-sensing structure has been simulated using the parameters of the fabricated pressure sensor and from the simulation result a pressure sensitivity of approximately 0.2283 mV/psi (33.11 mV/MPa) has been observed for input pressure ranging from 0 to 100 psi with a step size of 10 psi. The simulated and experimentally tested pressure sensitivities of the pressure sensor are in close agreement with each other. Originality/value This current mirror readout circuit-based MEMS pressure sensor is new and fully compatible to standard CMOS processes and has a promising application in the development CMOS-MEMS-integrated smart sensors.

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Sokolov, L. V., N. A. Agafonova i Yu V. Naumov. "Approximation of elastic deformations on the surface of a silicon piezoresistive pressure transducer with three-dimensional E-type micromechanical structure". Measurement Techniques 52, nr 3 (marzec 2009): 277–81. http://dx.doi.org/10.1007/s11018-009-9252-0.

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Marcillo, Omar, Jeffrey B. Johnson i Darren Hart. "Implementation, Characterization, and Evaluation of an Inexpensive Low-Power Low-Noise Infrasound Sensor Based on a Micromachined Differential Pressure Transducer and a Mechanical Filter". Journal of Atmospheric and Oceanic Technology 29, nr 9 (1.09.2012): 1275–84. http://dx.doi.org/10.1175/jtech-d-11-00101.1.

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Abstract The implementation, characterization, and evaluation of a low-cost infrasound sensor developed at the Infrasound Laboratory at the New Mexico Institute of Mining and Technology (Infra-NMT) are described. This sensor is based on a commercial micromachined piezoresistive differential pressure transducer that uses a mechanical high-pass filter to reject low-frequency outband energy. The sensor features a low-noise, 2.02-mPa rms (0.5–2 Hz), 5.47-mPa rms (0.1–20 Hz), or 5.62-mPa rms (0.05–20 Hz), flat response between 0.01 and at least 40 Hz; inband sensitivity of 45.13 ± 0.23 μV Pa−1; and a nominal linear range from −124.5 to +124.5 Pa. Intended for outdoor applications, the influence of thermal changes in the sensor’s response has been minimized by using a thermal compensated pressure transducer powered by an ultralow drift (<5 ppm °C−1) and noise (<4μV from peak to peak) voltage reference. The sensor consumes a minimum of 24 mW and operates with voltages above 8 V while drawing 3 mA of current. The Infra-NMT specifications described above were independently verified using the infrasound test chamber at the Sandia National Laboratories’ (SNL’s) Facility for Acceptance, Calibration, and Testing (FACT), and the following procedures are for comparison calibration against traceable reference stands in voltage and pressure. Because of the intended broad frequency response of this sensor, the testing chamber was configured in a double-reference sensor scheme. A well-characterized microbarometer (with a flat-amplitude response between 0.01 and 8 Hz) and a microphone (with a flat-amplitude response above 8 Hz) were used simultaneously in this double-reference test configuration.

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Voiculescu, I. R., M. E. Zaghloul, R. A. McGill i J. F. Vignola. "Modelling and measurements of a composite microcantilever beam for chemical sensing applications". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 220, nr 10 (1.10.2006): 1601–8. http://dx.doi.org/10.1243/09544062jmes150.

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A resonant microcantilever beam gas sensor was designed and fabricated in Carnegie Mellon University using complementary metal oxide semiconductor (CMU-CMOS) technology. The cantilever beam modified with a suitable sorbent coating was demonstrated as a chemical transducer for monitoring hazardous vapours and gases at trace concentrations. The design of the cantilever beam included interdigitated fingers to allow electrostatic actuation of the device and a piezoresistive Wheatstone bridge design to read out the deflection signal. The cantilever beam resonant frequency was modelled using the Euler-Bernoulli beam theory and ANSYS. The beam resonant frequency was measured with an optical laser Doppler vibrometer. Good agreement was obtained among the measured, simulated, and modelled resonant frequencies. A custom sorbent polymer layer was coated on the surface of the cantilever beam to allow its operation as a gas-sensing device. The frequency response as a function of exposure to the nerve agent simulant dimethylmethylphosphonate (DMMP) at different concentrations was measured, which allowed a demonstrated detection at a concentration of 20 ppb or 0.1 mg/m3. The air-polymer partition coefficient K, for DMMP was estimated and compared favourably with the known values for related polymers.

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Gu, Sen, Junhui Zhu, Peng Pan, Yong Wang i Changhai Ru. "A Miniature Piezoresistive Transducer and a New Temperature Compensation Method for New Developed SEM-Based Nanoindentation Instrument Integrated With AFM Function". IEEE Access 8 (2020): 104326–35. http://dx.doi.org/10.1109/access.2020.2999477.

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Peslin, R., D. Navajas, M. Rotger i R. Farre. "Validity of the esophageal balloon technique at high frequencies". Journal of Applied Physiology 74, nr 3 (1.03.1993): 1039–44. http://dx.doi.org/10.1152/jappl.1993.74.3.1039.

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The reliability of the esophageal balloon technique in measuring high-frequency changes in pleural pressure (Ppl) was investigated in six normal subjects by studying the amplitude ratio (A) and phase angle (phi) of esophageal (Pes) and mouth (Pm) pressures during airway occlusion and while pseudorandom pressure variations (2–32 Hz) were applied to the chest. The measurements were made with a common esophageal balloon-catheter system connected to a high-impedance piezoresistive transducer. When the cheeks were firmly supported, A averaged 1.08 +/- 0.063 at 2 Hz and 1.06 +/- 0.11 at 32 Hz. Pes increasingly led Pm with increasing frequency, and phi averaged 20.8 +/- 4.0 degrees at 32 Hz. Washing the airways with 80% He-20% O2 reduced phi by 50%. When the cheeks were not supported, A exhibited a strong positive frequency dependence, averaging 1.71 +/- 0.34 at 32 Hz, whereas phi increased much faster below 20 Hz and tended to decrease afterward. Because the esophageal transfer function Pes/Ppl = (Pes/Pm)/(Ppl/Pm), we could estimate Pes/Ppl by computing for individual subjects the pressure difference between the pleura and the mouth based on the lung and upper airway wall properties that were measured separately. The results suggest that the ratio of Pes and Ppl remains close to unity from 2 to 32 Hz, but Pes lags slightly behind Ppl (phi equals about -7 degrees at 32 Hz).

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Ceccarini, Maria Rachele, Valentina Palazzi, Raffaele Salvati, Irene Chiesa, Carmelo De Maria, Stefania Bonafoni, Paolo Mezzanotte i in. "Biomaterial Inks from Peptide-Functionalized Silk Fibers for 3D Printing of Futuristic Wound-Healing and Sensing Materials". International Journal of Molecular Sciences 24, nr 2 (4.01.2023): 947. http://dx.doi.org/10.3390/ijms24020947.

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This study illustrates the sensing and wound healing properties of silk fibroin in combination with peptide patterns, with an emphasis on the printability of multilayered grids, and envisions possible applications of these next-generation silk-based materials. Functionalized silk fibers covalently linked to an arginine–glycine–aspartic acid (RGD) peptide create a platform for preparing a biomaterial ink for 3D printing of grid-like piezoresistors with wound-healing and sensing properties. The culture medium obtained from 3D-printed silk fibroin enriched with RGD peptide improves cell adhesion, accelerating skin repair. Specifically, RGD peptide-modified silk fibroin demonstrated biocompatibility, enhanced cell adhesion, and higher wound closure rates at lower concentration than the neat peptide. It was also shown that the printing of peptide-modified silk fibroin produces a piezoresistive transducer that is the active component of a sensor based on a Schottky diode harmonic transponder encoding information about pressure. We discovered that such biomaterial ink printed in a multilayered grid can be used as a humidity sensor. Furthermore, humidity activates a transition between low and high conductivity states in this medium that is retained unless a negative voltage is applied, paving the way for utilization in non-volatile organic memory devices. Globally, these results pave the way for promising applications, such as monitoring parameters such as human wound care and being integrated in bio-implantable processors.

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L, Saipriya, Akepati Deekshitha, Shreya Shreya, Shubhika Verma, Swathi C i Manjunatha C. "Advances in Graphene Based MEMS and Nems Devices: Materials, Fabrication, and Applications". ECS Transactions 107, nr 1 (24.04.2022): 10997–1005. http://dx.doi.org/10.1149/10701.10997ecst.

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Microelectromechanical systems (MEMS) are generally known as miniaturized mechanical and electro-mechanical systems, whereas NEMS stands for nanoelectromechanical systems. Graphene is an atomically thin material that features unique properties, such as high carrier mobility, high mechanical strength, and piezoresistive electromechanical transduction, which makes it an extremely promising material for future MEMS and NEMS devices. Design and fabrication of MEMS/NEMS devices using graphene process includes trench etching, wafer backside etching, graphene transfer, and mass release, which are described in a comprehensive manner. This review provides interesting perspectives for lock-in detection of weak fluorescent signals, NEMS position detection, electromechanical control of the on-chip transmitter, and single-photon-level fast electromechanical optical modulation. There are various applications of MEMS/NEMS devices, namely radio frequency devices, optic NEMS, pressure sensors, inertial sensors, which have been discussed in detail. The review mainly focusses on the devices made up of graphene (atom-layer distance of ~0.335 nm) as a main electronic/mechanical material due to its remarkable mechanical and electrical (Young’s modulus of up to ~1 TPa cm2Vs-1) and charge-carrier mobility of up to 200,000, which makes it an extremely promising membrane and transducer material for MEMS/NEMS system applications. Modern MEMS/NEMS experiments utilize mechanical resonators to push the bounds of force and mass sensing, demonstrate novel electromechanical circuit applications, measure the structural properties of materials are also covered in this review.

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Dhanasekaran, Arumugam, i Sivasailam Kumaraswamy. "Study of Pulsation Pressures in the Stages of an Electric Submersible Pump at Shut-Off Under Various Speeds of Operation". Recent Patents on Mechanical Engineering 13, nr 2 (31.05.2020): 171–83. http://dx.doi.org/10.2174/2212797613666200220141119.

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Background: Electric Submersible Pumps (ESPs) are widely used in agricultural fields, petroleum, and various other industries. These pumps are mostly driven at a constant speed since an A.C. motor is normally used as the drive. However, ESPs can also be operated at various speeds by employing a Variable Frequency Drive (VFD). Several patents have been published in ESP. Normally these pumps are started with the discharge valve at its closed position in order to control the starting current. When the ESP runs at its shut-off position, it will develop a higher head and an increase in fluctuating pressure. In order to evaluate the effects of pressure fluctuation, its characteristics must be investigated. Objective: Experimentally investigate the characteristics of pressure pulsation which are generated at each stage of a multistage ESP during shut-off condition at various speeds. Methods: An ESP with five stages was selected for conducting experiments. A VFD was used for operating the ESP at five speed settings from 80 to 120 % of its rated speed. Piezoresistive transducer was placed at the delivery side of the pump to acquire the signals of unsteady pressure. The pump was operated at closed valve condition at each speed, and unsteady pressure signals due to pressure pulsation were captured. Results: Obtained results have indicated the presence of fundamental frequency pertaining to vane passing frequency and harmonics of higher frequencies. Conclusion: Study of pressure fluctuations at shut-off will help to analyze the failures of ESP due to vibration which occur when the pump runs at closed valve position for a prolonged length of time and stability of these pumps at lower flow rates.

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Lian-Zhong, Yu, i Bao Min-Hang. "Signal superimposition of piezoresistive pressure transducers". Sensors and Actuators 19, nr 1 (sierpień 1989): 23–31. http://dx.doi.org/10.1016/0250-6874(89)87054-4.

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Hencke, H. "Piezoresistive Pressure Transducers for Effective Flow Measurements". Measurement and Control 22, nr 8 (październik 1989): 237–39. http://dx.doi.org/10.1177/002029408902200802.

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Astashenkova, Olga N., Andrej V. Korlyakov i Victor V. Luchinin. "Micromechanics Based on Silicon Carbide". Materials Science Forum 740-742 (styczeń 2013): 998–1001. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.998.

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This paper describes using of silicon carbide for micromechanical systems. Low stressed sensitive membrane signal converters, thin film transducers and piezoresistive sensors were formed based on silicon carbide films. The mechanical properties of silicon carbide films were determined.

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33

Paleo, A. J., F. W. J. van Hattum, J. G. Rocha i S. Lanceros-Méndez. "Piezoresistive polypropylene–carbon nanofiber composites as mechanical transducers". Microsystem Technologies 18, nr 5 (28.03.2012): 591–97. http://dx.doi.org/10.1007/s00542-012-1471-7.

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Thuau, Damien. "(Invited) Organic Thin Films Transistors: From Mechanical to Biochemical Sensors". ECS Meeting Abstracts MA2022-02, nr 35 (9.10.2022): 1287. http://dx.doi.org/10.1149/ma2022-02351287mtgabs.

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Interest in organic electronic materials, and in particular their potential for low-cost fabrication over large areas, led to the development of organic field-effect transistors (OFETs). The potential of OFETs has been demonstrated in a variety of applications, including pixel drivers for displays, bionic skin, wearable electronics and sensitive chemical sensors that can operate in aqueous environments. OFETs use conjugated, semiconducting small molecules and polymers and offer an alternative to inorganic devices for applications in which facile processing on different substrates and tunable electronic properties are required. The flexibility requirement implies either performance stability towards deformation, or conversely, detectable response to the deformation itself. The knowledge of the electromechanical response of organic semiconductors to external stresses is therefore not only interesting from a fundamental point of view, but also necessary for the development of real world applications. To this end, this presentation highlights the importance of the choice of functional materials (organic semiconductors and dielectrics) as well as the relationship structure/properties in transistors based sensors. Organic semiconductors (OSCs) are promising transducer materials when applied in OFETs taking advantage of their electrical properties that highly depend on the morphology of the semiconducting film. The effects of a high-performance p-type organic semiconductor, namely dinaphtho [2,3-b:2,3-f] thieno [3,2–b] thiophene (DNTT) thickness on its piezoresistive sensitivity are presented. A critical thickness corresponding to the appearance of charge carriers percolation paths in the material can tune the gauge factors (GFs) by a factor 10. In addition, single crystal OSC are regarded as promising electroactive materials for strain sensing application. Herein this talk, we will present how strain induces simultaneous mobility changes along all three axes, and that in some cases the response is higher along directions orthogonal to the mechanical deformation. These variations cannot be explained by the modulation of intermolecular distances, but only by a more complex molecular reorganisation, which is particularly enhanced, in terms of response, by p-stacking and herringbone stacking. This microscopic knowledge of the relation between structural and mobility variations is essential for the interpretation of electromechanical measurements for crystalline organic semiconductors, and for the rational design of electronic devices. Alternatively, this talk will highlight how the use of an active gate dielectric layer such as poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) piezoelectric polymer can lead to highly efficient electro-mechanical sensitivity. In such case, the sensing mechanism of the electro-mechanical transducer originates from the piezoelectric material itself, which affects the electrical behavior of the transistor as signature of a mechanical event. The second part of this talk will focus on another kind of TFT based sensor, namely the organic electrochemical transistors (OECTs) which have found recently applications in chemical and biological sensing and interfacing and neuromorphic computing. OECT rely on ions that are injected from the electrolyte into polymer-based mixed conductors, thereby changing its doping state and hence its conductivity. While great progress has been achieved, organic mixed conductors frequently experience significant volumetric changes during ion uptake/rejection, i.e., during doping/ de-doping and charging/discharging. Although ion dynamics may be enhanced in expanded networks, these volumetric changes can have undesirable consequences, e.g., negatively affecting hole/electron conduction and severely shortening device lifetime. New materials able to transport ions and electrons/holes and that exhibits low swelling will be presented, expanding the materials-design toolbox for the creation of low-swelling soft mixed conductors with tailored properties and applications in bioelectronics and beyond.

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35

Zoric, Aleksandar, Dragoljub Martinovic i Slobodan Obradovic. "A simple 2D digital calibration routine for transducers". Facta universitatis - series: Electronics and Energetics 19, nr 2 (2006): 197–207. http://dx.doi.org/10.2298/fuee0602197z.

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A new practical algorithm for linearization and compensation of a two dimensional transducers transfer characteristic is described in this paper. The algorithm is suitable for smart sensor applications which incorporate a microprocessor. The calculating routine is simple and the algorithm requires initial calibration at nine points only. Theoretical and practical results are given for the assumed and measured piezoresistive pressure sensor characteristics, respectively. After correction based on 3?3 calibration, the obtained error was less than one percent of the full scale output in both cases.

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Potyrailo, Radislav A., Andrew Leach, William G. Morris i Sisira Kankanam Gamage. "Chemical Sensors Based on Micromachined Transducers with Integrated Piezoresistive Readout". Analytical Chemistry 78, nr 16 (sierpień 2006): 5633–38. http://dx.doi.org/10.1021/ac052086q.

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Ciampolini, P., A. Pierantoni i M. Rudan. "A CAD environment for the numerical simulation of integrated piezoresistive transducers". Sensors and Actuators A: Physical 47, nr 1-3 (marzec 1995): 618–22. http://dx.doi.org/10.1016/0924-4247(94)00973-l.

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Mathis, Maximilian, Dennis Vollberg, Matthäus Langosch, Dirk Göttel, Angela Lellig i Günter Schultes. "Novel method to reduce the transverse sensitivity of granular thin film strain gauges by modification of strain transfer". Journal of Sensors and Sensor Systems 9, nr 2 (17.07.2020): 219–26. http://dx.doi.org/10.5194/jsss-9-219-2020.

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Abstract. Strain gauges based on polyimide carrier foils and piezoresistive granular thin films are highly sensitive to strain. Unlike conventional metal foil, granular film strain gauges also have a pronounced sensitivity to strain acting in the transverse direction. A novel method that allows for the modification of the strain transfer is proposed and proven experimentally. The method is based on the creation of stand-alone polyimide paths, on top of which the piezoresistive thin film is located. In this way, the granular film hardly receives any transverse strain; hence, the transverse sensitivity is drastically reduced. A picosecond laser system can be used for both patterning of the thin film and for controlled ablation of polyimide in order to generate well-defined high path structures. The working principle of the method is demonstrated by simulation, followed by an experimental verification using measurements of the transverse gauge factor. Furthermore, the output signal of force transducers may be increased using granular thin film strain gauges of reduced transverse sensitivity.

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Kumar, Vijay, Antony Joseph, R. G. Prabhudesai, S. Prabhudesai, Surekha Nagvekar i Vimala Damodaran. "Performance Evaluation of Honeywell Silicon Piezoresistive Pressure Transducers for Oceanographic and Limnological Measurements*". Journal of Atmospheric and Oceanic Technology 22, nr 12 (1.12.2005): 1933–39. http://dx.doi.org/10.1175/jtech1812.1.

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Abstract Simultaneous calibrations of three temperature-compensated piezoresistive ruggedized precision “absolute” pressure transducers (Honeywell model PPTR0040AP5VB-BD), which have been designed specially for long-term coastal oceanographic and limnological measurements, have been carried out at four differing temperatures (10°, 20°, 30°, and 40°C) to evaluate their suitability for such applications. The full-scale pressure range of these shallow water absolute pressure sensors is ≈ 2800 hPa (equivalent to water depth of ≈ 18 m). Measurement results have been used to examine the transducers’ performance indicators, such as zero-point offset, accuracy, linearity, hysteresis, temperature sensitivity, and slope. Differing piezoresistive ruggedized precision absolute pressure transducers (PPTRs) exhibited differing zero-point offset values, ranging from 2 to −79 hPa. Temperature sensitivity of zero-point offset was ≈0.3 hPa over the temperature range 10°–40°C. The mean hysteresis over the full-scale absolute pressure range (≈2800 hPa) varied from approximately 2 to 8 hPa over the temperature range 10°–40°C. The slope of the least squares–fitted linear graph (taking the mean of ascending and descending pressures) was close to the ideal value of unity (deviation from 1 over the temperature range 10°–40°C was in the range of −0.001 to +0.005). Linearity was excellent, its mean over the entire pressure range being between ≈ −0.006% and 0.008% of full-scale (FS) over the above temperature range. The worst performance was exhibited at input pressures below ≈1500 hPa. Zero-point offset has played a significant role in deteriorating the accuracy of the PPTR, the mean accuracy (within ≈0.1% and −5%) having been exhibited by those transducers having offsets of 2 and −79 hPa, respectively. The mean accuracy exhibited temperature sensitivity of ≈1% in the range 10°–20°C and negligible sensitivity beyond 20°C. Use of a calibration equation significantly improved the mean static accuracy obtainable from the PPTR, to between −0.04% and 0.01% of FS. Evaluation results have indicated that a suitably calibrated temperature-compensated Honeywell PPTR provides an alternate cost-effective means for pressure measurements for coastal oceanographic and limnological studies.

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Peleg, Kalman, i Shabtai Shpigler. "Dynamic Matching of Acceleration Transducers". Journal of Dynamic Systems, Measurement, and Control 108, nr 4 (1.12.1986): 306–13. http://dx.doi.org/10.1115/1.3143799.

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Small mismatches between similarly manufactured accelerometers stem from slight differences between their flexural elements, seismic masses and their mountings, as well as variations in damping ratios. This is not detrimental for measuring absolute accelerations, but when it is desired to measure differential accelerations, very large errors may result. This is probably the main reason why transducers for measuring differential acceleration are not generally commercially available. Measuring the differential acceleration between two accelerometers mounted in different locations of an item provides a convenient means of measuring the relative velocity and displacement by single and double integration of the differential acceleration signal. To do this with good accuracy both accelerometers must have identical static and dynamic response characteristics. A method of matching the D.C. and dynamic response characteristics of any number of similarly manufactured piezoresistive acceleration transducers is described. This method is based on electronic compensation networks whereby the combined transfer functions of the transducers and their compensation networks are matched, enabling differential acceleration measurements with good accuracy. In addition to matching the effective transfer functions of the transducers, this method also significantly extends the operating frequency range in both absolute and differential measurements. The line taken is based on a general mathematical model, which was developed for quantifying error sources in differential measurements at large.

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Holbert, K. E., J. A. Nessel, S. S. McCready, A. S. Heger i T. H. Harlow. "Response of piezoresistive mems accelerometers and pressure transducers to high gamma dose". IEEE Transactions on Nuclear Science 50, nr 6 (grudzień 2003): 1852–59. http://dx.doi.org/10.1109/tns.2003.821373.

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Ausserlechner, Udo. "An Analytical Theory of Piezoresistive Effects in Hall Plates with Large Contacts". Advances in Condensed Matter Physics 2018 (4.06.2018): 1–24. http://dx.doi.org/10.1155/2018/7812743.

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Four-terminal transducers can be used to measure the magnetic field via the Hall effect or the mechanical stress via the piezoresistance effect. Both effects are described by an anisotropic conductivity tensor with small offdiagonal elements. This has led other authors to the conclusion that there is some kind of analogy. In both cases the output voltage depends on the geometry of the device and the size of the contacts. For Hall plates this influence is accounted for by the Hall-geometry factor. The alleged analogy proposes that the Hall-geometry factor also applies to four-terminal stress transducers. This paper shows that the analogy holds only for a limited class of devices. Moreover, it is shown that devices of different geometries may have identical magnetic field sensitivity but different mechanical stress sensitivities. Thus, shape optimization makes sense for mechanical stress sensors. In extreme cases the output voltages of vertical Hall-effect devices may have notable magnetic field sensitivity but zero mechanical stress sensitivity. As byproduct, exact analytical formulae for the equivalent resistor circuit of rectangular and circular devices with two perpendicular mirror symmetries are given. They allow for an accurate description of how mechanical stress and deformation affect the output offset voltage and the magnetic sensitivity of Hall-effect devices.

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Yang, Rui, Tina He, Mary Anne Tupta, Carine Marcoux, Philippe Andreucci, Laurent Duraffourg i Philip X.-L. Feng. "Probing contact-mode characteristics of silicon nanowire electromechanical systems with embedded piezoresistive transducers". Journal of Micromechanics and Microengineering 25, nr 9 (19.08.2015): 095014. http://dx.doi.org/10.1088/0960-1317/25/9/095014.

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Maharani, Afrisa, Abdul Muid i Nurhasanah Nurhasanah. "Rancang Bangun Alat Pengukur Volume Paru-paru Berbasis Sensor Tekanan Gas MPX5700DP dan Arduino Uno". PRISMA FISIKA 7, nr 3 (2.01.2020): 231. http://dx.doi.org/10.26418/pf.v7i3.37023.

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Telah dibuat alat pengukur volume paru-paru menggunakan sensor tekanan gas dan Arduino Uno. Sensor yang digunakan adalah jenis transduser piezoresistif seri MPX5700DP dengan tingkat sensitivitas sebesar 6,4 mV/kPa. Penelitian ini bertujuan untuk merancang sebuah alat yang mampu mengukur volume paru-paru manusia dengan mengaplikasikan pipa venturi, sensor tekanan gas dan mikrokontroler. Pengujian dilakukan dengan meniup pipa mouthpiece dan melihat hasilnya pada monitor. Hasil penelitian menunjukkan bahwa alat mampu mengukur FVC (Forced Vital Capacity) dan FEV1 (Forced Expiratory Volume in One Second), dengan eror sebesar 3,17% untuk FVC dan 1,22% untuk FEV1 dibandingkan dengan pengukuran menggunakan alat spirometer di rumah sakit.

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Solliec, Camille, i Jacky Mary. "Simultaneous measurements of fluctuating pressures using piezoresistive multichannel transducers as applied to atmospheric wind tunnel tests". Journal of Wind Engineering and Industrial Aerodynamics 56, nr 1 (kwiecień 1995): 71–86. http://dx.doi.org/10.1016/0167-6105(94)00013-4.

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Kaupert, Kevin A., i Thomas Staubli. "The Unsteady Pressure Field in a High Specific Speed Centrifugal Pump Impeller—Part I: Influence of the Volute". Journal of Fluids Engineering 121, nr 3 (1.09.1999): 621–26. http://dx.doi.org/10.1115/1.2823514.

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An experimental investigation is presented regarding the unsteady pressure field within a high specific speed centrifugal pump impeller (ωs = 1.7) which operated in a double spiral volute. For this, twenty-five piezoresistive pressure transducers were mounted within a single blade passage and sampled in the rotating impeller frame with a telemetry system. The influence of varying volume flux on the pressure transducers was evaluated in terms of pressure fluctuation magnitudes and phase differences. The magnitude information reveals that the pressure fluctuations from the impeller-volute interaction grew as the volume flux became further removed from the best efficiency point and as the trailing edge of the impeller blade was approached. These fluctuations reached 35% of the pump head in deep part load. The upstream influence of the volute steady pressure field dominates the unsteady pressure field within the impeller at all off design load points. Acquired signal phase information permits the identification of the pressure field unsteadiness within the impeller passage as fundamentally synchronized simultaneously with the volute tongue passing frequency. Special emphasis was placed on the volume flux regime where the pump and impeller pressure discharge characteristic undergo hysteresis, as impeller inlet and outlet recirculation commence and cease. A synthesis of the rotating transducers was performed to obtain unsteady blade loading parameters. The value of the unsteady lift coefficient varies on the order of 200% for a single blade in part load operation (at 45% bep), an abrupt fluctuation occurring as the fore running blade suction side passes a volute tongue. The unsteady moment coefficient and center of pressure are also shown to vary significantly during the impeller-volute tongue interaction.

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47

Thong, Trinh Quang, Margarita Guenther i Gerald Gerlach. "Development of hydrogel-based MEMS piezoresistive sensors for detection of solution pH and glucose concentration". Vietnam Journal of Mechanics 34, nr 4 (30.11.2012): 281–88. http://dx.doi.org/10.15625/0866-7136/34/4/2344.

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Hydrogels are water-swollen polymeric materials that maintain a distinct three-dimensional structure. Manipulation of hydrogel structure has produced stimuli sensitive hydrogels, which change their swelling degree or undergo phase transition in response to minimal changes in environmental conditions. This paper presents the development of hydrogel-based sensors for measurement of solution pH and glucose concentration using commercial MEMS piezoresistive pressure transducers. pH-sensitive PVA/PAA and glucose-sensitive AAm/3-APB/BIS hydrogels are used in the experiments. Two types of sensor packaging, one is used as solution container and the other used to dip into solution have been performed. The measurements for different solutions having pH values between 1 to 11 and glucose concentrations between 2.5 mM and 15 mM have been carried out. The output characteristics of sensors have been demonstrated showing the long-term reproduction and relatively good sensitivity, namely approximately 20 mV/pH for pH sensor and 7 mV/1 mM of glucose concentration for glucose sensor.

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Sosa, J., Juan A. Montiel-Nelson, R. Pulido i Jose C. Garcia-Montesdeoca. "Design and Optimization of a Low Power Pressure Sensor for Wireless Biomedical Applications". Journal of Sensors 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/352036.

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A blood pressure sensor suitable for wireless biomedical applications is designed and optimized. State-of-the-art blood pressure sensors based on piezoresistive transducers in a full Wheatstone bridge configuration use low ohmic values because of relatively high sensitivity and low noise approach resulting in high power consumption. In this paper, the piezoresistance values are increased in order to reduce by one order of magnitude the power consumption in comparison with literature approaches. The microelectromechanical system (MEMS) pressure sensor, the mixed signal circuits signal conditioning circuitry, and the successive approximation register (SAR) analog-to-digital converter (ADC) are designed, optimized, and integrated in the same substrate using a commercial 1 μm CMOS technology. As result of the optimization, we obtained a digital sensor with high sensitivity, low noise (0.002 μV/Hz), and low power consumption (358 μW). Finally, the piezoresistance noise does not affect the pressure sensor application since its value is lower than half least significant bit (LSB) of the ADC.

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Cavazzini, G., G. Pavesi i G. Ardizzon. "Pressure instabilities in a vaned centrifugal pump". Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 225, nr 7 (4.08.2011): 930–39. http://dx.doi.org/10.1177/0957650911410643.

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This article reports the acoustic and fluid-dynamical analyses of large-scale instabilities in a vaned centrifugal pump. The unsteady pressure fields at full/part load were measured by dynamic piezoresistive transducers placed at the impeller discharge and on an instrumented diffuser vane. To spectrally characterize the inception and the evolution of the unsteady phenomena, spectral analyses of the pressure signals were carried out both in frequency and time–frequency domains. Numerical analyses were carried out on the same pump with the help of the commercial code CFX. All the computations were performed using the unsteady ‘transient’ model with a time step corresponding to about 1° of the impeller rotation. The turbulence was modelled by the detached eddy simulation model. Numerical pressure signals were compared with the experimental ones to verify the development of the same pressure instabilities. The unsteady numerical flow fields were analysed to study the fluid-dynamical evolution of the instabilities and investigate their origin.

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Hsu, Y. W., S. S. Lu i P. Z. Chang. "Piezoresistive response induced by piezoelectric charges in n-type GaAs mesa resistors for application in stress transducers". Journal of Applied Physics 85, nr 1 (styczeń 1999): 333–40. http://dx.doi.org/10.1063/1.369452.

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