Journal articles on the topic 'Integrated pressure transducer'
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Maralani, Ayden, Levent Beker, and Albert P. Pisano. "Toward Integrated Pressure Sensors for Temperatures up to 600°C." Journal of Microelectronics and Electronic Packaging 13, no. 4 (October 1, 2016): 163–68. http://dx.doi.org/10.4071/imaps.522.
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The main objective of this study is to develop pressure-sensing systems by integrating pressure transducers with the interface circuitry in one package that can withstand harsh environments, particularly high temperatures up to 600°C. To achieve that, both pressure transducer and interface circuitry are individually required to operate and survive up to 600°C with acceptable degrees of reliability. This article reports performance evaluation of fabricated 4H-SiC Junction Field Effect Transistors along with differential pairs for use in the interface circuitry. The test results are very promising and show stable performances from 25°C up to 600°C. Moreover, design, fabrication, and early test (from 25°C up to 100°C) of an SiC-based circular diaphragm-type pressure transducer are also reported.
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Maralani, Ayden, Levent Beker, and Albert P. Pisano. "Towards Integrated Sensors for Environments with Temperatures up to 600 °C." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2016, HiTEC (January 1, 2016): 000051–55. http://dx.doi.org/10.4071/2016-hitec-51.
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Abstract The main objective is to develop sensing systems by integrating transducers such as pressure sensing elements with the interface circuitry in one package that can withstand harsh environments, particularly high temperatures up to 600 °C. To achieve that, both pressure transducer and interface circuitry are individually required to operate and survive up to 600 °C with acceptable degrees of reliability. This paper reports performance evaluation of fabricated 4H-SiC JFETs along with differential pairs for use in the interface circuitry. The test results are very promising and show stable performances from 25 °C up to 600 °C. Moreover, design, fabrication, and early test of a SiC based circular diaphragm type pressure transducer is also reported.
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Wang, Wenjie, Weihao Shi, Peter Thomas, and Mingsui Yang. "Design and Analysis of Two Piezoelectric Cymbal Transducers with Metal Ring and Add Mass." Sensors 19, no. 1 (January 2, 2019): 137. http://dx.doi.org/10.3390/s19010137.
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Based on traditional sandwich structure, two piezoelectric transducers were designed to meet the strict underwater application backgrounds such as high pressure, corrosion resistance, and high strength. Both transducers integrated most of previous researches while one transducer has a multilayer cavity structure which is different from the other structure and previous transducer structures. After a detailed simulation analysis of every structural parameter, key parameters were pointed out to have an obvious influence on its performance. Then, two models were constructed and compared with chosen sets of geometry parameters and manufacturing process, which can also provide a reference for low-frequency transducer design. The simulation results and experimental results of our transducers show a good consistency which indicates the cavity structure can reduce the resonance frequency.
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Yalikun, Yaxiaer, and Yo Tanaka. "Ultra-thin glass sheet integrated transparent diaphragm pressure transducer." Sensors and Actuators A: Physical 263 (August 2017): 102–12. http://dx.doi.org/10.1016/j.sna.2017.05.047.
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Temirov, N. E., and N. N. Temirov. "Experience in clinical use of active ultrasonic handpiece with integrated pressure transducer." Modern technologies in ophtalmology, no. 5 (October 20, 2021): 99–101. http://dx.doi.org/10.25276/2312-4911-2021-5-99-101.
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Purpose: Clinical testing of new ultrasonic handpiece with active transducer of pressure Active Sentry (AS), optional for phacomachine Cebturion. The study is based on the analysis of surgical records and disease histories of 100 patients operated on age-related cataract, by the method of ultrasonic phacoemulsification. All surgeries were performed by one surgeon by using the phacomachine Cebturion with settings ensuring safety and efficacy of the procedure. The half of all procedures were performed using the conventional ultrasonic handpiece (OZ), and the other half – using the handpiece with active transducer of pressure (AS). The evaluation criteria used include the following: pressure level of irrigating fluid used for nucleofragmentation; nucleofragmentation time; percentage loss of the posterior corneal epithelium cells. Results. With equal safety of the procedure, using the ultrasonic handpiece with active transducer of pressure (AS) in the course of nucleofragmentation enables the reduction of irrigating fluid pressure (BSS) by 20 mm Hg, followed by the reduction of BBS volume passing through the anterior chamber by 30 ml upon the average. The rate of the intraoperative endothelial cells loss when using the ultrasonic active handpiece is also lower, as compared to the conventional one, 8.3±3.2 vs 10.2±2.1, respectively. However this difference could not be confirmed by statistical data, possibly due to the limited sample of patients. Conclusions. The introduction of a new active ultrasonic handpiece (AS) for phacomachine Cebturion allows further reduction of procedural injury, while maintaining high efficiency of nucleofragmentation. Key words: рhacoemulsification of cataract, ultrasonic handle, active transducer of ocular pressure, reducing of surgical injury.
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Kumar, Shashi, Gaddiella Diengdoh Ropmay, Pradeep Kumar Rathore, Peesapati Rangababu, and Jamil Akhtar. "Fabrication and testing of PMOS current mirror-integrated MEMS pressure transducer." Sensor Review 40, no. 2 (November 23, 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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Mikhailenko, I. V., A. T. Orlov, and B. K. Serdega. "Polarization-modulation diagnostics of thermal stresses in an integrated pressure transducer." Semiconductors 51, no. 4 (April 2017): 498–502. http://dx.doi.org/10.1134/s1063782617040145.
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Ledesma, Eyglis, Iván Zamora, Francesc Torres, Arantxa Uranga, Vassil Tzanov, Nuria Barniol, Eloi Marigó, and Mohan Soundara-Pandian. "Squared PMUT with Enhanced Pressure Sensitivities." Proceedings 2, no. 13 (November 27, 2018): 925. http://dx.doi.org/10.3390/proceedings2130925.
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This study presents a squared AlN piezoelectric micromachined ultrasonic transducer (PMUT). Using this PMUT greater level of output pressure and higher reception sensitivity has been achieved, compared with the state-of-the-art. Another outstanding characteristic for this PMUT is that it can be monolithically integrated on CMOS substrate, being remarkably advantageous in relation to the bonding method implemented until now.
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Hu, C. M., N. Guo, H. Du, and L. M. Xu. "Dynamic characteristics of stacked piezoelectric transducers of ultrasonic wire bonders used in integrated circuit packaging." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 217, no. 3 (March 1, 2003): 341–52. http://dx.doi.org/10.1243/095440603762870009.
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Currently ultrasonic wire bonders with precision capillary tips are widely used for bonding wires to integrated circuit (IC) chips and circuits. However, the quality and strength of a bond may be affected significantly by the change of vibration during the bonding process. It is therefore important to understand the dynamics of the bonding process as well as the vibration characteristics of the bonding system, so bonding quality may be monitored. This paper reports the study on the dynamic characteristics of the stacked piezoelectric transducers used in the ultrasonic wire bonding system. The vibration characteristics are first analysed using the finite element method with resonant frequency and vibration modes. The predicted impedance response is compared with the measurement using a high-pressure (HP) impedance analyser. The displacement profile along the transducer assembly, which includes a piezoelectric stack, clamping and horn sections, are also analysed. The effects of multilayer and polarization on the response of the transducer are discussed. It was found there is good agreement between the prediction and measurement, and bending and extension modes may be excited differently according to the polarization configuration used in the multilayer stack.
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Chen, Rui, Zhongkui Chen, Charles Wang Wai Ng, and Jian Liu. "Development of a pore gas pressure transducer used in unsaturated soils at high water content." E3S Web of Conferences 92 (2019): 02003. http://dx.doi.org/10.1051/e3sconf/20199202003.
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Pore gas pressure in soil is an important parameter in many geoscience applications such as evaluating the effects of trapped pore gas pressure on water infiltration through soil mass, optimizing the design of gas extraction wells in landfills and assessing the performance of landfill covers in reducing landfill gas emission. In addition, it has been observed that pore gas pressure affects slope stability in unsaturated soils. However, the pore gas pressure build-up induced by water infiltration is generally ignored in most slope stability analysis by assuming gas pressure to be zero. Therefore, pore gas pressure measurement in soils is crucial to better understand the unsaturated soil behaviour. However, most of current measuring techniques of pore gas pressure are affected by water interruption during the measurement in unsaturated soils, especially at high water content. In this study, a novel gas pressure transducer was developed to measure the pore gas pressure in unsaturated soil within a wide range of water content. The newly developed pore gas pressure transducer mainly consists of an electrical pressure sensor package and an integrated membrane filter which can prevent water leaching through the membrane but allow gas to pass it freely. The performance of the gas pressure transducer was evaluated by a series of permeation tests. The results show that the developed gas pressure transducer has a good repeatability to monitor gas pressure and has a relatively fast response to the gas pressure change in compacted soils. This transducer is able to measure pore gas pressure range of 0~50 kPa of soils within a relatively high range of soil water content.
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Zenker, Benjamin, Martin Dannemann, Sirko Geller, Klaudiusz Holeczek, Oliver Weißenborn, M. Ercan Altinsoy, and Niels Modler. "Structure-Integrated Loudspeaker Using Fiber-Reinforced Plastics and Piezoelectric Transducers—Design, Manufacturing and Validation." Applied Sciences 10, no. 10 (May 16, 2020): 3438. http://dx.doi.org/10.3390/app10103438.
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In the present study, it could be shown that by integration of a piezoceramic transducer in a fiber-reinforced door side panel, a flat loudspeaker can be realized. Taking into account the given restrictions, the integration position has been identified, where the geometry decouples the vibrating membrane from the supporting surface. With the help of an acoustic finite-element simulation, the main design variables of the integration position were found and the relevant effects for sound radiation were made visible. The manufacturing of the test specimen with piezoceramic transducers was performed using vacuum-assisted resin infusion and the long fiber injection procedure. The effect on the real sound radiation behavior of the door side panel with a material-immanent loudspeaker was experimentally determined using laser scanning vibrometry and sound pressure measurements. The presented work shows, for the first time, the high potential of acoustic functionalization of lightweight structures during the manufacturing process for the realization of lightweight and space-saving loudspeakers in a production-ready process.
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Benken, Alexander, and Yogesh Gianchandani. "Passive Wireless Pressure Sensing for Gastric Manometry." Micromachines 10, no. 12 (December 10, 2019): 868. http://dx.doi.org/10.3390/mi10120868.
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We describe a wireless microsystem for gastrointestinal manometry that couples a microfabricated capacitive transducer to a dual-axis inductor, forming a resonant inductor-capacitor (LC) sensor within an ingestible 3D printed biocompatible capsule measuring ø 12 mm × 24 mm. An inductively coupled external telemetry unit wirelessly monitors the pressure dependent resonant frequency of the LC sensor, eliminating the need for integrated power sources within the ingested capsule. In vitro tests in saline show pressure response of −0.6 kHz/mmHg, interrogation distance up to 6 cm, and resolution up to 0.8 mmHg. In vivo functionality is validated with gastrointestinal pressure monitoring in a canine beagle over a 26-hour period.
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Salavitabar, Arash, Feng Qiu, Allen Kunselman, and Akif Ündar. "Evaluation of the Quadrox-I neonatal oxygenator with an integrated arterial filter." Perfusion 25, no. 6 (August 10, 2010): 409–15. http://dx.doi.org/10.1177/0267659110380773.
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Cardiopulmonary bypass (CPB) can be a potential cause of morbidity in patients for several reasons, including significantly higher gaseous microemboli (GME) formation than extracorporeal life support (ECLS) and physiological circulation, diverted blood flow from the patient via an open purge line of the arterial filter, and pressure drop across the oxygenator that is used in the circuit. Using a combined oxygenator and arterial filter may minimize these harmful factors and can effectively reduce the chances for postoperative morbidity. This study investigated the new QUADROX-i Neonatal Oxygenator (D-72145, Maquet, Hirrlingen, Germany) with an integrated arterial filter in terms of the hemodynamic properties and ability to clear GME in response to hypothermic versus normothermic conditions, open versus closed arterial filter purge line, and varying flow rates in a simulated CPB circuit identical to that of the clinical setting. A flow probe, pressure transducer, and Emboli Detection and Classification (EDAC) quantifier transducer were placed upstream and downstream to the oxygenator to measure changes in each parameter. The circuit was primed with fresh human blood with an hematocrit (Hct) of 26% diluted with Ringer’s lactate solution. Five milliliters of air were injected proximal to the venous cardiotomy reservoir, under non-pulsatile perfusion, with flow rates of 500 ml/min, 750 ml/min, and 1000 ml/min. A total of 8 air bolus injections were made at each individual set of conditions for a total of 96 injections. Results showed that the QUADROX-i Neonatal Oxygenator with an integrated filter has excellent hemodynamic properties with extremely low pressure drops and blood flow diverted from the patient, as well as high rates of GME capturing. The arterial filter purge line has a significant effect on the degree of blood flow diverted from the patient (p < 0.001), but does not affect pressure drop across the oxygenator.
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Yang, Chen, Xiaohua Jian, Xinle Zhu, Jiabing Lv, Yang Jiao, Zhile Han, Antonios Stylogiannis, Vasilis Ntziachristos, George Sergiadis, and Yaoyao Cui. "Sensitivity Enhanced Photoacoustic Imaging Using a High-Frequency PZT Transducer with an Integrated Front-End Amplifier." Sensors 20, no. 3 (January 30, 2020): 766. http://dx.doi.org/10.3390/s20030766.
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Photoacoustic (PA) imaging is a hybrid imaging technique that can provide both structural and functional information of biological tissues. Due to limited permissible laser energy deposited on tissues, highly sensitive PA imaging is required. Here, we developed a 20 MHz lead zirconium titanate (PZT) transducer (1.5 mm × 3 mm) with front-end amplifier circuits for local signal processing to achieve sensitivity enhanced PA imaging. The electrical and acoustic performance was characterized. Experiments on phantoms and chicken breast tissue were conducted to validate the imaging performance. The fabricated prototype shows a bandwidth of 63% and achieves a noise equivalent pressure (NEP) of 0.24 mPa/√Hz and a receiving sensitivity of 62.1 μV/Pa at 20 MHz without degradation of the bandwidth. PA imaging of wire phantoms demonstrates that the prototype is capable of improving the detection sensitivity by 10 dB compared with the traditional transducer without integrated amplifier. In addition, in vitro experiments on chicken breast tissue show that structures could be imaged with enhanced contrast using the prototype and the imaging depth range was improved by 1 mm. These results demonstrate that the transducer with an integrated front-end amplifier enables highly sensitive PA imaging with improved penetration depth. The proposed method holds the potential for visualization of deep tissue structures and enhanced detection of weak physiological changes.
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Jiang, Feilong, Hao Liu, and Daxia Chai. "Humanoid Lower Limb: Design, Analysis, Observer-Based Fuzzy Adaptive Control and Experiment." Mathematical Problems in Engineering 2021 (February 10, 2021): 1–15. http://dx.doi.org/10.1155/2021/6694765.
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With flexibility similar to human muscles, pneumatic artificial muscles (PAMs) are widely used in bionic robots. They have a high power-mass ratio and are only affected by single-acting pneumatic pressure. Some robots are actuated by a pair of PAMs in the form of antagonistic muscles or joints through a parallel mechanism. The pneumatic pressure and length of PAMs should be measured simultaneously for feedback using a pressure transducer and draw-wire displacement sensor. The PAM designed by the FESTO (10 mm diameter) is too small to install a draw-wire displacement sensor coaxially and cannot measure muscle length change directly. To solve this problem, an angular transducer is adopted to measure joint angles as a whole. Then, the inertia of the lower limb is identified, and observer-based fuzzy adaptive control is introduced to combine with integrated control of the angular transducer. The parameters of the fuzzy control are optimized by the Gaussian basis neural network function, and an observer is developed to estimate the unmeasured angular accelerations. Finally, two experiments are conducted to confirm the effectiveness of the method. It is demonstrated that piriformis and musculi obturator internus act as agonistic muscle and antagonistic muscles alternatively, and iliopsoas is mainly responsible for strengthening because of the constant output force. Piriformis has a greater influence on yaw and roll angles, while musculi obturator internus is the one that influences the pitch angle the most. Due to joint friction, the dead zone of the high-speed on-off valve, lag of compressed air in the trachea, and coupling among angles are very difficult to realize precise trajectory tracking of the pitch, yaw, and roll angles simultaneously.
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Rose, Shane. "High Temperature CMOS Reliability and Drift." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2010, HITEC (January 1, 2010): 000040–46. http://dx.doi.org/10.4071/hitec-srose-ta21.
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Quartzdyne precision pressure transducers are required to continuously operate at 200°C for more than 5 years (>1 year at 225°C). Future electronics are targeted for 250°C operation. The current transducer electronics are based on 3 custom ASICs; an Oscillator, Voltage Regulator and a Frequency counter. Understanding custom integrated circuit component drift and interconnect life at temperature is crucial for the next generation of sensor applications. In this study, basic components are aged under bias at 225°C, 250°C and 275°C. Components include P-FET transistors, polysilicon resistors, and a diode connected PNP transistor. Measured parameter drift versus temperature and electrical stress is used to estimate device drift over time. Measured voltage regulator drift is compared with estimated drift based on resistor and diode measurements. Standard aluminum circuit interconnect life is measured at 3 current densities and temperatures. A modified current density guide is derived from Black's equation. Measured circuit interconnect life is shown to increase when diffusion barriers are present. Powered Quartzdyne hybrid circuit life results at 225°C are compared to expected lifetimes.
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Gao, Jian, Anren Yao, Yeyi Zhang, Guofan Qu, Chunde Yao, Shemin Zhang, and Dongsheng Li. "Investigation into the Relationship between Super-Knock and Misfires in an SI GDI Engine." Energies 14, no. 8 (April 9, 2021): 2099. http://dx.doi.org/10.3390/en14082099.
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The super-knock poses new challenges for further increasing the power density of spark ignition (SI) engines. The critical factors and mechanism connecting regarding the occurrence of super-knock are still unclear. Misfire is a common phenomenon in SI engines that the mixture in cylinder is not ignited normally, which is often caused by spark plug failure. However, the effect of misfire on engine combustion has not been paid enough attention to, particularly regarding connection to super-knock. The paper presents the results of experimental investigation into the relationship between super-knock and misfires at low speed and full load conditions. In this work, a boosted gasoline direct injection (GDI) engine with an exhaust manifold integrated in the cylinder head was employed. Four piezoelectric pressure transducers were used to acquire the data of a pressure trace in cylinder. The spark plugs of four cylinders were controlled manually, of which the ignition system could be cut off as demanded. In particular, a piezoelectric pressure transducer was installed at the exhaust pipe before the turbocharger to capture the pressure traces in the exhaust pipe. The results illustrated that misfires in one cylinder would cause super-knock in the other cylinders as well as the cylinder of itself. After one cylinder misfired, the unburned mixture would burn in the exhaust pipe to produce oscillating waves. The abnormal pressure fluctuation in the exhaust pipe was strongly correlated with the occurrence of super-knock. The sharper the pressure fluctuation, the greater the intensity of knock in the power cylinder. The cylinder whose exhaust valve overlapped with the exhaust valve of the misfired cylinder was prone to super-knock.
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Kim, Gwangho, Sanghwa Jeong, and Yang Jun Kang. "Ultrasound Standing Wave-Based Cell-to-liquid Separation for Measuring Viscosity and Aggregation of Blood Sample." Sensors 20, no. 8 (April 17, 2020): 2284. http://dx.doi.org/10.3390/s20082284.
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When quantifying mechanical properties of blood samples flowing in closed fluidic circuits, blood samples are collected at specific intervals. Centrifugal separation is considered as a required procedure for preparing blood samples. However, the use of centrifuge is associated with several issues, including the potential for red blood cell (RBC) lysis, clotting activation, and RBC adhesions in the tube. In this study, an ultrasonic transducer is employed to separate RBCs or diluent from blood sample. The ultrasonic radiation force is much smaller than the centrifugal force acting in centrifuge, it can avoid critical issues occurring under centrifuge. Then, the RBC aggregation and blood viscosity of the blood sample are obtained using the microfluidic technique. According to the numerical results, ultrasonic transducers exhibited a maximum quality factor at an excitation frequency of 2.1 MHz. Periodic pattern of acoustic pressure fields were visualized experimentally as a column mode. The half wavelength obtained was as 0.5 λ = 0.378 ± 0.07 mm. The experimental results agreed with the analytical estimation sufficiently. An acoustic power of 2 W was selected carefully for separating RBCs or diluent from various blood samples (i.e., Hct = 20% ~ 50%; diluent: plasma, 1x phosphate-buffered saline (PBS), and dextran solution). The present method was employed to separate fixed blood samples which tended to stack inside the tube while using the centrifuge. Fixed RBCs were collected easily with an ultrasonic transducer. After various fixed blood samples with different base solutions (i.e., glutaraldehyde solution, 1x PBS, and dextran solution) were prepared using the present method, RBC aggregation and the viscosity of the blood sample are successfully obtained. In the near future, the present method will be integrated into ex vivo or in vitro fluidic circuit for measuring multiple mechanical properties of blood samples for a certain longer period.
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Gao, Dongyue, Zhanjun Wu, Lei Yang, and Yuebin Zheng. "Integrated impedance and Lamb wave–based structural health monitoring strategy for long-term cycle-loaded composite structure." Structural Health Monitoring 17, no. 4 (July 7, 2017): 763–76. http://dx.doi.org/10.1177/1475921717717312.
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Impedance of a sensor is sensitivity to small structural damage which surrounds the sensor. Lamb wave propagation provides higher damage detection efficiency in the range of large area. Both methods have been widely developed for structural health monitoring. This article presents integrated impedance and Lamb wave–based structural health monitoring strategy for composite pressure vessels. The output of the presented structural health monitoring strategy includes distribution and classification of damage and health condition of sensor network under varying internal pressure loading environments. In the strategy, a novel damage index adjusting method for Lamb wave damage detection is developed based on the signal features of real and imaginary parts of the sensor impedance. First, the potential structural damage is pre-warned by monitoring the impedance variation of the piezoelectric transducer sensor network. Then, the health condition of sensor network under the working condition is assessed by impedance-based self-diagnosis method; subsequently, the Lamb wave damage index is adjusted based on the result of sensor self-diagnosis. Finally, on the basis of sensor self-diagnosis and damage index adjustment result, damage identification and classification are performed. Practical efficacy of the structural health monitoring approach is tested by the damage monitoring experiment on loaded composite structure.
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Sano, Chikako, Manabu Ataka, Gen Hashiguchi, and Hiroshi Toshiyoshi. "An Electret-Augmented Low-Voltage MEMS Electrostatic Out-of-Plane Actuator for Acoustic Transducer Applications." Micromachines 11, no. 3 (March 4, 2020): 267. http://dx.doi.org/10.3390/mi11030267.
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Despite the development of energy-efficient devices in various applications, microelectromechanical system (MEMS) electrostatic actuators yet require high voltages to generate large displacements. In this respect, electrets exhibiting quasi-permanent electrical charges allow large fixed voltages to be integrated directly within electrode structures to reduce or eliminate the need of DC bias electronics. For verification, a − 40 V biased electret layer was fabricated at the inner surface of a silicon on insulator (SOI) structure facing a 2 μm gap owing to the high compatibility of silicon micromachining and the potassium-ion-electret fabrication method. A − 10 V electret-augmented actuator with an out-of-plane motion membrane reached a sound pressure level (SPL) of 50 dB maximum with AC input voltage of V i n = 5 V pp alone, indicating a potential for acoustic transducer usage such as microspeakers. Such devices with electret biasing require only the input signal voltage, thus contributing to reducing the overall power consumption of the device system.
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Zenit, Roberto, and Melany L. Hunt. "Mechanics of Immersed Particle Collisions." Journal of Fluids Engineering 121, no. 1 (March 1, 1999): 179–84. http://dx.doi.org/10.1115/1.2821999.
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The present work investigates the mechanics of particle collisions submerged in a liquid using a simple pendulum experiment. Particle trajectories for different particles in water are measured using a high-speed digital camera and the magnitude of the collision is recorded using a high-frequency-response pressure transducer at the colliding surface. The particle deceleration occurs at distances less than half a particle diameter from the wall. The measured collision impulse increases with impact velocity and particle mass. Comparisons are drawn between the measured pressures and the predictions of basic impact mechanics assuming a perfectly elastic collision. A control-volume model is proposed that accounts for the fluid inertia and viscosity. When a particle approaches a planar surface or another particle, the fluid is squeezed prior to contact, reducing the initial kinetic energy and decelerating the particle. The pressure profile is integrated over the surface of the particle to obtain a force that is a function of the initial particle Reynolds number, Reo, and the ratio of the densities of the particle and fluid phases, ρp/ρf. The model predicts a critical Stokes number at which the particle reaches the wall with zero velocity. Comparisons between the proposed model and the experimental measurements show qualitative agreement.
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Mešić, Elmedin, Nedim Pervan, Adis J. Muminović, Adil Muminović, and Mirsad Čolić. "Development of Knowledge-Based Engineering System for Structural Size Optimization of External Fixation Device." Applied Sciences 11, no. 22 (November 15, 2021): 10775. http://dx.doi.org/10.3390/app112210775.
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The development process of the knowledge-based engineering (KBE) system for the structural size optimization of external fixation device is presented in this paper. The system is based on algorithms for generative modeling, finite element model (FEM) analysis, and size optimization. All these algorithms are integrated into the CAD/CAM/CAE system CATIA. The initial CAD/FEM model of external fixation device is verified using experimental verification on the real design. Experimental testing is done for axial pressure. Axial stress and displacements are measured using tensometric analysis equipment. The proximal bone segment displacements were monitored by a displacement transducer, while the loading was controlled by a force transducer. Iterative hybrid optimization algorithm is developed by integration of global algorithm, based on the simulated annealing (SA) method and a local algorithm based on the conjugate gradient (CG) method. The cost function of size optimization is the minimization of the design volume. Constrains are given in a form of clinical interfragmentary displacement constrains, at the point of fracture and maximum allowed stresses for the material of the external fixation device. Optimization variables are chosen as design parameters of the external fixation device. The optimized model of external fixation device has smaller mass, better stress distribution, and smaller interfragmentary displacement, in correlation with the initial model.
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Zamora, Iván, Eyglis Ledesma, Arantxa Uranga, and Núria Barniol. "Miniaturized 0.13-μm CMOS Front-End Analog for AlN PMUT Arrays." Sensors 20, no. 4 (February 22, 2020): 1205. http://dx.doi.org/10.3390/s20041205.
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This paper presents an analog front-end transceiver for an ultrasound imaging system based on a high-voltage (HV) transmitter, a low-noise front-end amplifier (RX), and a complementary-metal-oxide-semiconductor, aluminum nitride, piezoelectric micromachined ultrasonic transducer (CMOS-AlN-PMUT). The system was designed using the 0.13-μm Silterra CMOS process and the MEMS-on-CMOS platform, which allowed for the implementation of an AlN PMUT on top of the CMOS-integrated circuit. The HV transmitter drives a column of six 80-μm-square PMUTs excited with 32 V in order to generate enough acoustic pressure at a 2.1-mm axial distance. On the reception side, another six 80-μm-square PMUT columns convert the received echo into an electric charge that is amplified by the receiver front-end amplifier. A comparative analysis between a voltage front-end amplifier (VA) based on capacitive integration and a charge-sensitive front-end amplifier (CSA) is presented. Electrical and acoustic experiments successfully demonstrated the functionality of the designed low-power analog front-end circuitry, which outperformed a state-of-the art front-end application-specific integrated circuit (ASIC) in terms of power consumption, noise performance, and area.
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Włodarczyk, Marek. "Fiber optic-based in-cylinder pressure sensor for advanced engine control and monitoring." Combustion Engines 151, no. 4 (November 1, 2012): 3–8. http://dx.doi.org/10.19206/ce-117016.
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This paper describes the design and performance of a miniature cylinder pressure sensor packaged either as a stand-alone device or integrated with a cylinder head gasket, glow plug, fuel injector, or spark plug. Benefitting from a fiber-optic based design the sensing element can operate at ultra-high temperatures and is not affected by EMI. This low cost device utilizes the principle of light intensity changes transmitted by two optical fibers upon reflection from a metal diaphragm deflecting under the effect of pressure. When the diaphragm thickness and shape are optimized, the sensor can operate up to 5 billion pressure cycles. The device is compensated for all temperature effects encountered in combustion engines, resulting from the thermal shock, engine load changes, and under-hood temperature fluctuations. Due to the diaphragm small thermal mass the sensor is subject to the thermal shock error if no heat shield is employed. While a suitable shield can almost eliminate the thermal shock error, it can get clogged in engines fuelled by diesel or landfill gas. For such engines a dual diaphragm construction offers a robust solution against soot and other combustion deposits as well as minimum thermal shock error. In comparison to a water cooled piezoelectric quartz transducer the present sensor offers the accuracy of ±1.5% of reading at pressures above 5 bars, ±0.1 bar error at pressure below 5 bars during compression, and the thermal shock error ranging from 0.1 bar to 0.3 bar dependent if a single or dual diaphragm is used. Such accuracy is possible with both stand-alone sensors as well as those 1.7 mm in diameter used in the “pressure sensing” cylinder head gaskets, glow plugs, fuel injectors, or spark plugs. This accuracy is maintained under all combustion conditions, sensor tip continuous temperatures up to 380 oC, signal conditioner temperature range of –40 oC to 140 oC, pressures up to 350 bar, and over frequency range of 0.1 Hz to 30 kHz. Such remarkable accuracy allows advanced engine controls based on highly accurate values of the Indicated Mean Effective Pressure, Mass Fraction Burned, Maximum Pressure Gradient, and Peak Pressure. Benefitting from sensor’s high accuracy at both low and high pressures the device enables closed-loop control of fuel injection as well as in-cylinder prediction of mass air flow and engine NOx emission levels.
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Jiang, Runkun, Lei Mei, and Q. M. Zhang. "COMSOL Multiphysics Modeling of Architected Acoustic Transducers in Oil Drilling." MRS Advances 1, no. 24 (2016): 1755–60. http://dx.doi.org/10.1557/adv.2016.46.
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ABSTRACTIn the oil and gas industry, acoustic transducers have been found to provide valuable geological sonic information such as compressional wave velocity, shear wave velocity, and rock formation slowness. These data can be used to indicate lithology, determine porosity, detect over-pressured formation zones, and check well to well correlation. One category of such acoustic transducers is equipped with piezoelectric elements. Conventional piezoelectric transducers are packaged by epoxy resin. Because of the liquid nature of uncured epoxy resin, it is difficult to position the piezoelectric elements accurately. The introduction of polyether ether ketone (PEEK) as the packaging material solved this issue. Due to the ease of machining on solid form, architectures of the composite acoustic transducers can be devised with great flexibility and creativity. These designs can be modeled with finite element methods (FEM) and the best design for the oil drilling application can be finalized and fabricated.COMSOL Multiphysics® solves problems in a programming environment that integrates relevant physics. In this case, it includes electrical circuit, solid mechanics, acoustics, and piezoelectricity. Here a compete model and procedure to study the performance of an architected composite acoustic transducer is provided. The displacement analysis gives insights into the resonance modes of the piezoelectric elements. The acoustics analysis gives the necessary information on the acoustic performance of the transducers, such as acoustic pressure spatial distribution, acoustic pressure frequency response, transmitting voltage response, and directivity. These are important criteria to judge the effectiveness of an architected transducer.
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Zimin, V. N., N. Z. Salakhov, Yu A. Chaplygin, D. V. Shabratov, and N. A. Shelepin. "Precision integrated pressure transducers." Measurement Techniques 38, no. 1 (January 1995): 33–35. http://dx.doi.org/10.1007/bf00976743.
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Yilmaz, Gürkan, Michaël Rapin, Diogo Pessoa, Bruno M. Rocha, Antonio Moreira de Sousa, Roberto Rusconi, Paulo Carvalho, Josias Wacker, Rui Pedro Paiva, and Olivier Chételat. "A Wearable Stethoscope for Long-Term Ambulatory Respiratory Health Monitoring." Sensors 20, no. 18 (September 8, 2020): 5124. http://dx.doi.org/10.3390/s20185124.
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Lung sounds acquired by stethoscopes are extensively used in diagnosing and differentiating respiratory diseases. Although an extensive know-how has been built to interpret these sounds and identify diseases associated with certain patterns, its effective use is limited to individual experience of practitioners. This user-dependency manifests itself as a factor impeding the digital transformation of this valuable diagnostic tool, which can improve patient outcomes by continuous long-term respiratory monitoring under real-life conditions. Particularly patients suffering from respiratory diseases with progressive nature, such as chronic obstructive pulmonary diseases, are expected to benefit from long-term monitoring. Recently, the COVID-19 pandemic has also shown the lack of respiratory monitoring systems which are ready to deploy in operational conditions while requiring minimal patient education. To address particularly the latter subject, in this article, we present a sound acquisition module which can be integrated into a dedicated garment; thus, minimizing the role of the patient for positioning the stethoscope and applying the appropriate pressure. We have implemented a diaphragm-less acousto-electric transducer by stacking a silicone rubber and a piezoelectric film to capture thoracic sounds with minimum attenuation. Furthermore, we benchmarked our device with an electronic stethoscope widely used in clinical practice to quantify its performance.
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Julinda, Marisa, Taufik Sumarsongko, and Gian Nur Alamsyah. "Comparison of the retentive ability on incisal bite force between aloe vera and poly(methyl-vinyl-ether) adhesive materials in complete acrylic denture measured by modified pressure transducer." Padjadjaran Journal of Dentistry 33, no. 1 (March 31, 2021): 81. http://dx.doi.org/10.24198/pjd.vol33no1.23907.
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Introduction: Patients with acrylic complete denture, usually have a confidence issue in using their complete dentures to chew and speak, because of concern about detached of the denture from its place and pain on the alveolar ridge. Application denture adhesive material ordinarily can solve the problem. Mostly, denture adhesives in the market are made from synthetic material poly(methyl-vinyl-ether) but nowadays aloe vera extract is believed to be a substitute to synthetic denture adhesive material. The purpose of this study was to compare the retentive ability of the prothesis which applied incisal bite forces among the complete denture applied by denture adhesive poly(methyl-vinyl-ether), aloe vera extract and and without denture adhesive as control. Methods: This true-experimental research used 10 samples from patients who used acrylic complete denture and meet suitable criteria. Samples were tested in three different interventions, the first one applied by denture adhesive made from poly(methyl-vinyl-ether), the second one applied by denture adhesive made from aloe vera extract and the third one as a control group, sample was tested without any application of denture adhesive. Retentive ability on incisal bite forces was measured by modified pressure transducer with integrated software. Data was analysis using ANOVA method. Results: Anterior bite force as control 20,98 N, aloe vera 23,42 N, poly (methyl-vinyl-ether) 21,25 N and without denture adhesive as control. Significant differences in the incisal bite force dislodgement of dentures that were applied with Aloe vera-based denture adhesive s with p-value of 0.0088. Conclusion: Denture adhesive made from Aloe vera extract had the highest adhesiveness incisal bite force value compared to denture adhesive made from poly(methyl-vinyl-ether) and without denture adhesive.
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Zhang, Xue Zhi, Alfred Yu, and Henry Hu. "Characterization of Local Cavity Pressures in Squeeze Casting of Magnesium Alloy AM50." Advanced Materials Research 936 (June 2014): 1666–70. http://dx.doi.org/10.4028/www.scientific.net/amr.936.1666.
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In this study, the experimental measurement of the pressure distribution in a cylindrical die cavity for squeeze casting of magnesium alloy AM50A was carried out. Piezo-electric quartz pressure transducers were integrated into a die cavity for real-time pressure measurements. The experimental results revealed that local cavity pressures at various locations changed with time in the duration of squeeze casting solidification and cooling. The pressure transfer rate varied considerably within the casting geometry. The distribution of local cavity pressures was inhomogeneous in the cavity.
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KS, Suresh, Prof (Dr ). Vijayakumar N, and Prof (Dr ). Sukesh Kumar A. "Classification of Doppler Ultrasound Blood Flow Signals of Lower Extremity Arteries for the Early Detection of Diabetic Foot." International Journal of Engineering and Advanced Technology 10, no. 6 (August 30, 2021): 210–15. http://dx.doi.org/10.35940/ijeat.f3081.0810621.
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Peripheral arterial disease is one of the key indicators of diabetic foot, which can be easily identified by ultrasound diagnostic techniques. The work aims to detect diabetic foot in early stages by classifying the blood flow signals of lower extremity arteries being captured by ultrasound doppler methods. Samples are collected from diabetic patients with and without having probable symptoms of arterial diseases. Doppler examination has been conducted on posterior tibial artery for 354 subjects with a transducer of 8 MHz frequency. The auscultation, method of listening sounds of internal organs, is employed as medical diagnostic tool for identifying pathological conditions. Each artery in the human body has a unique profile of Doppler flow. This fixed profile may be changed with the presence of a particular disease. The received signal has a spectrum of Doppler-shifted signals with respect to the existence of a velocity profile across the vessel lumen. Changes to the shape of this profile is an indicator of the severity of disease. Various features are extracted by using various statistical and signal processing functions. The feature analysis was accomplished with machine learning algorithms. Naïve Bayes, Tree and SVM algorithms are employed with MATLAB Toolboxes. Comparing the performance of these algorithms, the Tree method is found superior than the others. So, the proposed classification methodology can be employed as a key factor for the early stage detection of diabetic foot. As diabetic foot is correlated with many other parameters which effects the pressure and flow velocity of lower extremities, an integrated disease prediction model is proposed by incorporating the ultrasound doppler technique.
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Li, Liang, Lei, Hong, Li, Li, Ghaffar, Li, and Xiong. "Quantitative Analysis of Piezoresistive Characteristic Based on a P-type 4H-SiC Epitaxial Layer." Micromachines 10, no. 10 (September 20, 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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Lazarevikj, Marija, Valentino Stojkovski, and Viktor Iliev. "Оdrеđivаnjе brzinе struјаnjа vаzduhа u prаvоugаоnоm zаtvоrеnоm cevovodu korišćenjem metoda polja brzina." Energija, ekonomija, ekologija 23, no. 2 (2021): 57–63. http://dx.doi.org/10.46793/eee21-2.57l.
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In the technical practice, it is often necessary to measure or control the fluid flow rate in pipelines and channels. The velocity-area method requires a number of meters located at specified points in a suitable cross-section of closed conduits. Simultaneous measurements of local mean velocity with the meters are integrated over the gauging section to provide the discharge. In this paper, three approaches of this method are applied on a rectangular closed conduit to determine the air flow rate with integration techniques used to compute the discharge assume velocity distributions that closely approximate known laws, especially in the neighborhood of solid boundaries. For this purpose, meters for velocity were 7 Pitot tubes placed vertically in predefined measurement points covering the conduit height, and moved horizontally along the conduit width. The position of the Pitot tubes along the conduit width was monitored and controlled by a linear displacement transducer. Pressure is measured using digital sensors. The first technique for determination of air flow rate is on basis of fixed (stopping) measuring points across the conduit width as averaged values of local velocity, the second one is semi continual measurement of velocity profile by applying interpolation between the average local velocity on fixed (stopping) points and measured velocity in the movement between two positions, and the third is by continuously moving the Pitot tubes without stopping. The results of the three techniques are calculated and presented using different types of software. Considering the last technique, comparison of results is made applying different movement speeds of the Pitot tubes in order to examine their influence on the velocity profile.
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Fisher-Adams, G., KK Jr Wong, G. Podsakoff, SJ Forman, and S. Chatterjee. "Integration of adeno-associated virus vectors in CD34+ human hematopoietic progenitor cells after transduction." Blood 88, no. 2 (July 15, 1996): 492–504. http://dx.doi.org/10.1182/blood.v88.2.492.bloodjournal882492.
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Gene transfer vectors based on adeno-associated virus (AAV) appear promising because of their high transduction frequencies regardless of cell cycle status and ability to integrate into chromosomal DNA. We tested AAV-mediated gene transfer into a panel of human bone marrow or umbilical cord-derived CD34+ hematopoietic progenitor cells, using vectors encoding several transgenes under the control of viral and cellular promoters. Gene transfer was evaluated by (1) chromosomal integration of vector sequences and (2) analysis of transgene expression. Southern hybridization and fluorescence in situ hybridization analysis of transduced CD34 genomic DNA showed the presence of integrated vector sequences in chromosomal DNA in a portion of transduced cells and showed that integrated vector sequences were replicated along with cellular DNA during mitosis. Transgene expression in transduced CD34 cells in suspension cultures and in myeloid colonies differentiating in vitro from transduced CD34 cells approximated that predicted by the multiplicity of transduction. This was true in CD34 cells from different donors, regardless of the transgene or selective pressure. Comparisons of CD34 cell transduction either before or after cytokine stimulation showed similar gene transfer frequencies. Our findings suggest that AAV transduction of CD34+ hematopoietic progenitor cells is efficient, can lead to stable integration in a population of transduced cells, and may therefore provide the basis for safe and efficient ex vivo gene therapy of the hematopoietic system.
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Munduate, Xabier, Frank N. Coton, and Roderick A. McD Galbraith. "An Investigation of the Aerodynamic Response of a Wind Turbine Blade to Tower Shadow." Journal of Solar Energy Engineering 126, no. 4 (November 1, 2004): 1034–40. http://dx.doi.org/10.1115/1.1765683.
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This paper presents results from a wind tunnel based examination of the response of a wind turbine blade to tower shadow in head-on flow. In the experiment, one of the blades of a small-scale, two-bladed, downwind turbine was instrumented with miniature pressure transducers to allow recording of the blade surface pressure response through tower shadow. The surface pressures were then integrated to provide the normal force coefficient responses presented in this paper. It is shown that it is possible to reproduce the measured responses using an indicially formulated unsteady aerodynamic model applied to a cosine wake velocity deficit. It is also shown that agreement between the model and the measured data can be improved by careful consideration of the velocity deficit geometry.
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Zimin, V. N., D. V. Shabratov, N. A. Shelepin, and Yu A. Chaplygin. "Integrated pressure transducers for the normal range from 0.04 to 30 MPa." Measurement Techniques 37, no. 2 (February 1994): 174–75. http://dx.doi.org/10.1007/bf00979208.
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Chatterjee, Saswati, Wei Li, Christie Ann Wong, Grace Fisher-Adams, Di Lu, Mausumee Guha, James A. Macer, Stephen J. Forman, and K. K. Wong. "Transduction of Primitive Human Marrow and Cord Blood-Derived Hematopoietic Progenitor Cells With Adeno-Associated Virus Vectors." Blood 93, no. 6 (March 15, 1999): 1882–94. http://dx.doi.org/10.1182/blood.v93.6.1882.406k03_1882_1894.
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We evaluated the capacity of adeno-associated virus (AAV) vectors to transduce primitive human myeloid progenitor cells derived from marrow and cord blood in long-term cultures and long-term culture-initiating cell (LTC-IC) assays. Single-colony analyses showed that AAV vectors transduced CD34+ and CD34+38− clonogenic cells in long-term culture. Gene transfer was readily observed in LTC-ICs derived from 5-, 8-, and 10-week cultures. Recombinant AAV (rAAV) transduction was observed in every donor analyzed, although a wide range of gene transfer frequencies (5% to 100%) was noted. AAV transduction of LTC-ICs was stable, with week-8 and -10 LTC-ICs showing comparable or better transduction relative to week-5 LTC-ICs. Fluorescence in situ hybridization (FISH) analyses performed to determine the fate of AAV vectors in transduced cells showed that 9% to 28% of CD34+ and CD34+38− cells showed stable vector integration as evidenced by chromosome-associated signals in metaphase spreads. Comparisons of interphase and metaphase FISH suggested that a fraction of cells also contained episomal vector at early time points after transduction. Despite the apparent loss of the episomal forms with continued culture, the number of metaphases containing integrated vector genomes remained stable long term. Transgene transcription and placental alkaline phosphatase (PLAP) expression was observed in CD34+, CD34+38−LTC-ICs in the absence of selective pressure. These results suggest that primitive myeloid progenitors are amenable to genetic modification with AAV vectors.
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Olbrechts, Benoit, Bertrand Rue, Thomas Pardoen, Denis Flandre, and Jean Pierre Raskin. "Routes towards Novel Active Pressure Sensors in SOI Technology." Advanced Materials Research 276 (July 2011): 145–55. http://dx.doi.org/10.4028/www.scientific.net/amr.276.145.
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In this paper, novel pressure sensors approach is proposed and described. Active devices and oscillating circuits are directly integrated on very thin dielectric membranes as pressure transducers. Involved patterning of the membrane is supposed to cause a drop of mechanical robustness. Finite elements simulations are performed in order to better understand stress/strain distribution and as an attempt to explain the early burst of patterned membranes. Smart circuit designs are reported as solutions with high sensitivity and reduced footprint on membranes.
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Ion, Marian, Silviu Dinulescu, Bogdan Firtat, Mihaela Savin, Octavian N. Ionescu, and Carmen Moldovan. "Design and Fabrication of a New Wearable Pressure Sensor for Blood Pressure Monitoring." Sensors 21, no. 6 (March 16, 2021): 2075. http://dx.doi.org/10.3390/s21062075.
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In recent years, research into the field of materials for flexible sensors and fabrication techniques directed towards wearable devices has helped to raise awareness of the need for new sensors with healthcare applicability. Our goal was to create a wearable flexible pressure sensor that could be integrated into a clinically approved blood pressure monitoring device. The sensor is built from a microfluidic channel encapsulated between two polymer layers, one layer being covered by metal transducers and the other being a flexible membrane containing the microfluidic channel, which also acts as a sealant for the structure. The applied external pressure deforms the channel, causing changes in resistance to the microfluidic layer. Electrical characterization has been performed in 5 different configurations, using alternating current (AC) and (DC) direct current measurements. The AC measurements for the fabricated pressure sensor resulted in impedance values at tens of hundreds of kOhm. Our sensor proved to have a high sensitivity for pressure values between 0 and 150 mm Hg, being subjected to repeatable external forces. The novelty presented in our work consists in the unique technological flow for the fabrication of the flexible wearable pressure sensor. The proposed miniaturized pressure sensor will ensure flexibility, low production cost and ease of use. It is made of very sensitive microfluidic elements and biocompatible materials and can be integrated into a wearable cuffless device for continuous blood pressure monitoring.
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FRANCO-AYALA, M. F., D. E. CEBALLOS HERRERA, G. G. PEREZ SANCHEZ, F. MARTINEZ-PINON, and J. A. ALVAREZ-CHAVEZ. "A MODEL OF THE ARTERIAL WALL INTERACTION WITH A BLOOD PRESSURE SENSOR TRANSDUCER FIXED IN PROXIMITY." Latin American Applied Research - An international journal 44, no. 2 (April 30, 2014): 167–71. http://dx.doi.org/10.52292/j.laar.2014.436.
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MEMS technology is an option for the development of a pressure sensor which allows the monitoring of several bio-signals in humans. In this work, a comparison is made between the typical elasticity and viscosity presented in several arteries in the human body and those present in MEMS silicon microstructures based on membranes in proximity with an arterial wall. The main purpose is to identify which types of microstructures are mechanically compatible with human arteries. The ultimate goal is to integrate a blood pressure sensor which can be implanted in proximity with an artery. The expected benefits for this type of sensor are mainly the reduction in problems associated with the use of bulk devices through the day and during several days. Such a sensor could provide precise blood pressure readings in a continuous or periodic form, i.e. information that is especially important for some critical cases of hypertension patients. The modeling work involved in this paper, accounts for the analysis of micro displacements present in the membrane of a MEMs silicone microstructure placed directly on a human arterial wall, at different heart rates. The modeling includes the effects of elasticity and viscosity of the silicone structure on the pressure measurement. Additionally, the sensitivity of the membrane to detect slight variations in the blood pressure is presented.
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Rojas Suárez, J. P., J. A. Pabón León, and M. S. Orjuela Abril. "Acoustic emissions in the valuation of the combustion chamber pressure of an engine." Journal of Physics: Conference Series 2102, no. 1 (November 1, 2021): 012014. http://dx.doi.org/10.1088/1742-6596/2102/1/012014.
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Abstract Internal combustion engines demand advanced monitoring methodologies to promote efficient operation; particularly, the combustion pressure plays a central role in the overall performance, which promotes the utilization of transducers that hinders. Therefore, the present study introduces an acoustic emission methodology that serves for indirect combustion pressure measurements. Accordingly, the compound methodology integrates the Hilbert transform and the complex cepstrum using neural networks to accomplish pressure signal reconstruction. Results demonstrated that the proposed methodology featured robust performance while estimating pressure signals as it mitigates the combined noise effect produced by variations in engine speed, engine load, and fuel type. Moreover, the reconstructed signal facilitated the determination of key performance parameters such as peak pressure, pressure timing, and effective mean pressure. Relative error amounted to less than 10%, which ratified the robustness of the indirect pressure measurements. In conclusion, acoustic signal techniques represent an adequate approach to estimate the combustion pressure at variable engine conditions.
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SILVA, Rogério Mariotto Bitetti da, Fernando A. M. HERBELLA, and Daniel GUALBERTO. "NORMATIVE VALUES FOR A NEW WATER-PERFUSED HIGH RESOLUTION MANOMETRY SYSTEM." Arquivos de Gastroenterologia 55, suppl 1 (August 6, 2018): 30–34. http://dx.doi.org/10.1590/s0004-2803.201800000-40.
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ABSTRACT BACKGROUND: Esophageal manometry is the most reliable method to evaluate esophageal motility. High resolution manometry (HRM) provides topographic contour colored plots (Clouse Plots) with simultaneous analysis from the pharynx to the stomach. Both solid state and water-perfused systems are available. OBJECTIVE: This study aims to determinate the normative data for a new water-perfused HRM. METHODS: HRM was made in 32 healthy volunteers after 8 hours fasting. HRM system used consisted of a 24-channel water-perfused catheter (Multiplex, Alacer Biomedica, São Paulo, Brazil). The reusable catheter is made of polyvinyl chloride (PVC) with 4.7 mm of diameter. Side holes connected to pressure transducers are spaced 2 cm for the analysis from the pharynx to the lower esophageal sphincter (LES). Holes are spaced 5 mm and 120° in a spiral disposition in the LES area. The sensors encompass 34 cm in total. Upper esophageal sphincter (UES) parameters studied were basal and relaxation pressures. Esophageal body parameters were distal contractile integral (DCI), distal latency (DL) and break. LES parameters studied were basal pressure, integrated residual pressure (IRP), total and abdominal length. Variables are expressed as mean ± standard deviation, median (interquartile range) and percentiles 5-95th. RESULTS: All volunteers (17 males, aged 22-62 years) completed the study and tolerated the HRM procedure well. Percentiles 5-95th range were calculated: Upper Esophageal Sphincter (UES) basal pressure 16.7-184.37 (mmHg), DL: 6.2-9.1 (s), DCI: 82.72-3836.61 (mmHg.s.cm), break: <7.19 (cm), LES basal pressure: 4.89-37.16 (mmHg), IRP: 0.55-15.45 (mmHg). CONCLUSION: The performance and normative values obtained for this low-cost water-perfused HRM seems to be adequate for clinical use.
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Sosa, J., Juan A. Montiel-Nelson, R. Pulido, and 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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Holmes, Christopher, James C. Gates, and P. G. R. Smith. "Integrated optical differential pressure transducers achieved using thin buckled silica membranes and direct UV written planar Bragg gratings." Sensors and Actuators A: Physical 168, no. 1 (July 2011): 14–21. http://dx.doi.org/10.1016/j.sna.2011.03.030.
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Kwak, Jean Won, Mengdi Han, Zhaoqian Xie, Ha Uk Chung, Jong Yoon Lee, Raudel Avila, Jessica Yohay, et al. "Wireless sensors for continuous, multimodal measurements at the skin interface with lower limb prostheses." Science Translational Medicine 12, no. 574 (December 16, 2020): eabc4327. http://dx.doi.org/10.1126/scitranslmed.abc4327.
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Precise form-fitting of prosthetic sockets is important for the comfort and well-being of persons with limb amputations. Capabilities for continuous monitoring of pressure and temperature at the skin-prosthesis interface can be valuable in the fitting process and in monitoring for the development of dangerous regions of increased pressure and temperature as limb volume changes during daily activities. Conventional pressure transducers and temperature sensors cannot provide comfortable, irritation-free measurements because of their relatively rigid construction and requirements for wired interfaces to external data acquisition hardware. Here, we introduce a millimeter-scale pressure sensor that adopts a soft, three-dimensional design that integrates into a thin, flexible battery-free, wireless platform with a built-in temperature sensor to allow operation in a noninvasive, imperceptible fashion directly at the skin-prosthesis interface. The sensor system mounts on the surface of the skin of the residual limb, in single or multiple locations of interest. A wireless reader module attached to the outside of the prosthetic socket wirelessly provides power to the sensor and wirelessly receives data from it, for continuous long-range transmission to a standard consumer electronic device such as a smartphone or tablet computer. Characterization of both the sensor and the system, together with theoretical analysis of the key responses, illustrates linear, accurate responses and the ability to address the entire range of relevant pressures and to capture skin temperature accurately, both in a continuous mode. Clinical application in two prosthesis users demonstrates the functionality and feasibility of this soft, wireless system.
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Safaei, Mohsen, Sylvain Dupre, Elias Hoummadi, and Steven R. Anton. "Design, analysis, and fabrication of a piezoelectric force tray for total knee replacements." Journal of Intelligent Material Systems and Structures 30, no. 20 (October 5, 2019): 3163–76. http://dx.doi.org/10.1177/1045389x19880003.
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Force plates have been widely adopted in biomechanical gait analysis to measure reaction forces and the center of pressure. In this work, the force plate concept is miniaturized and extended for use within the polyethylene bearing insert of a total knee replacement. A simplified rectangular-shaped force plate with multiple integrated piezoelectric sensors, including designs with six and eight transducers, is presented in this work. The performance of the sensory system is investigated through finite element analysis and experimental validation. Initially, the ability of the two designs in sensing compartmental forces and contact point locations on one side of the force plate is numerically investigated. Selected designs of the force plate are then fabricated and used to experimentally validate the performance of the system. The results show a maximum error of less than 6% and 4.5% in compartmental force amplitude sensing for the force plates with six and eight transducers, respectively. The force plates were able to detect the contact point location with maximum errors of less than 1 mm. The relatively small sensing error quantities show the potential of using a piezoelectric force plate sensor design in total knee replacement as well as other force sensing applications.
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Rodrigues, Matheus S., Pedro M. Lazari, Marco C. P. Soares, and Eric Fujiwara. "Characterization of Hand Gestures by a Smartphone-Based Optical Fiber Force Myography Sensor." Engineering Proceedings 2, no. 1 (November 14, 2020): 46. http://dx.doi.org/10.3390/ecsa-7-08178.
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In this paper, a smartphone-integrated, optical fiber sensor based on the force myography technique (FMG), which characterizes the stimuli of the forearm muscles in terms of mechanical pressures, was proposed for the identification of hand gestures. The device’s flashlight excites a pair of polymer optical fibers and the output signals are detected by the camera. The light intensity is modulated through wearable, force-driven microbending transducers placed in the forearm and the acquired optical signals are processed by an algorithm based on decision trees and residual error. The sensor provided a hit rate of 87% regarding four postures, yielding reliable performance with a simple, portable, and low-cost setup embedded on a smartphone.
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Ledesma, Eyglis, Ivan Zamora, Arantxa Uranga, Francesc Torres, and Núria Barniol. "Enhancing AlN PMUTs’ Acoustic Responsivity within a MEMS-on-CMOS Process." Sensors 21, no. 24 (December 17, 2021): 8447. http://dx.doi.org/10.3390/s21248447.
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In this paper, guidelines for the optimization of piezoelectrical micromachined ultrasound transducers (PMUTs) monolithically integrated over a CMOS technology are developed. Higher acoustic pressure is produced by PMUTs with a thin layer of AlN piezoelectrical material and Si3N4 as a passive layer, as is studied here with finite element modeling (FEM) simulations and experimental characterization. Due to the thin layers used, parameters such as residual stress become relevant as they produce a buckled structure. It has been reported that the buckling of the membrane due to residual stress, in general, reduces the coupling factor and consequently degrades the efficiency of the acoustic pressure production. In this paper, we show that this buckling can be beneficial and that the fabricated PMUTs exhibit enhanced performance depending on the placement of the electrodes. This behavior was demonstrated experimentally and through FEM. The acoustic characterization of the fabricated PMUTs shows the enhancement of the PMUT performance as a transmitter (with 5 kPa V−1 surface pressure for a single PMUT) and as a receiver (12.5 V MPa−1) in comparison with previously reported devices using the same MEMS-on-CMOS technology as well as state-of-the-art devices.
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Guenther, Margarita, Gerald Gerlach, Thomas Wallmersperger, Mahender Nath Avula, Seung Hei Cho, X. Xie, B. V. Devener, et al. "Smart Hydrogel-Based Biochemical Microsensor Array for Medical Diagnostics." Advances in Science and Technology 85 (September 2012): 47–52. http://dx.doi.org/10.4028/www.scientific.net/ast.85.47.
Full textAbstract:
With the rapid development of micro systems technology and microelectronics, smart implantable wireless electronic systems are emerging for the continuous surveillance of relevant parameters in the body and even for closed-loop systems with a sensor feed-back to drug release systems. With respect to diabetes management, there is a critical societal need for a fully integrated sensor array that can be used to continuously measure a patient’s blood glucose concentration, pH, pCO2 and colloid oncotic pressure twenty four hours a day on a long-term basis. In this work, thin films of metabolite-specific or “smart” hydrogels were combined with microfabricated piezoresistive pressure transducers to obtain “chemomechanical sensors” that can serve as selective and versatile wireless biomedical sensors and sensor arrays for a continuous monitoring of several metabolites. Sensor response time and accuracy with which sensors can track gradual changes in glucose, pH, CO2 and ionic strength, respectively, was estimated in vitro using simulated physiological solutions. The biocompatibility and hermeticity of the developed multilayer encapsulation for the microsensor array has been investigated concerning the long-term stability and enduring functionality that is desired for permanent implants.
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Makarov, Denys. "Compliant Magnetic Field Sensor Technologies." Engineering Proceedings 6, no. 1 (May 17, 2021): 8. http://dx.doi.org/10.3390/i3s2021dresden-10066.
Full textAbstract:
We review the recent progress in the field of shapeable magnetoelectronics allowing the realization of mechanically imperceptible electronic skins, which enable perception of the geomagnetic field (e-skin compasses), featuring sensitivities down to ultra-small fields of sub-50 nT. We demonstrate that e-skin compasses allow humans to orient with respect to Earth’s magnetic field ubiquitously. The biomagnetic orientation enables novel interactive devices for virtual and augmented reality applications, which is showcased by realizing touchless control of virtual units in a game engine using omnidirectional magnetosensitive skins. This concept is further extended by demonstrating a compliant magnetic microelectromechanical platform (m-MEMS), which is able to transduce both tactile (via mechanical pressure) and touchless (via magnetic field) stimulations simultaneously and discriminate them in real time. These devices are crucial for interactive electronics and human–machine interfaces, but also for the realization of smart soft robotics with highly compliant integrated feedback systems including in medicine for physicians and surgeons.
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Goh, Qi-Lun, Pei-Song Chee, Eng-Hock Lim, and Danny Wee-Kiat Ng. "An AI-Assisted and Self-Powered Smart Robotic Gripper Based on Eco-EGaIn Nanocomposite for Pick-and-Place Operation." Nanomaterials 12, no. 8 (April 12, 2022): 1317. http://dx.doi.org/10.3390/nano12081317.
Full textAbstract:
High compliance and muscle-alike soft robotic grippers have shown promising performance in addressing the challenges in traditional rigid grippers. Nevertheless, a lack of control feedback (gasping speed and contact force) in a grasping operation can result in undetectable slipping and false positioning. In this study, a pneumatically driven and self-powered soft robotic gripper that can recognize the grabbed object is reported. We integrated pressure (P-TENG) and bend (B-TENG) triboelectric sensors into a soft robotic gripper to transduce the features of gripped objects in a pick-and-place operation. Both the P-TENG and B-TENG sensors are fabricated using a porous structure made of soft Ecoflex and Euthethic Gallium-Indium nanocomposite (Eco-EGaIn). The output voltage of this porous setup has been improved by 63%, as compared to the non-porous structure. The developed soft gripper successfully recognizes three different objects, cylinder, cuboid, and pyramid prism, with a good accuracy of 91.67% and has shown its potential to be beneficial in the assembly lines, sorting, VR/AR application, and education training.