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Kurniawan, W., R. Tjandra i E. Obermeier. "Bulk-type piezoresistive force sensor for high pressure applications". Procedia Chemistry 1, nr 1 (wrzesień 2009): 544–47. http://dx.doi.org/10.1016/j.proche.2009.07.136.
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Chen, Jin Jun, i Ting Xiang. "Robot Soft Grabbing with New Piezoresistive Tactile Sensor". Advanced Materials Research 744 (sierpień 2013): 501–4. http://dx.doi.org/10.4028/www.scientific.net/amr.744.501.
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A type of tactile sensors based on piezoresistive principle is designed for the robot grab force detection and control. According to human behaves and awareness, the robot grabbing control program imitate human hand grasp active perception and action mechanisms. With the tactile sensors, the slip and grasping process pressure signal is sampled and analysed by general time-domain statistical parameter, and a simpler control algorithm is researched. In the experiment the robot has accomplished soft grabbing by modeling human hand action and applied appropriate grabbing force on objects of different weights or material by means of the control algorithm. Experiments suggest that this sensor and action biomimetic process is suitable to be used in the tele-presence technology application in the case of the visible range or visual equipment aid especially.
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Sitaramgupta V, V. S. N., Arjun B. S, Bhagaban Behera, Deepak Padmanabhan i Hardik J. Pandya. "A Ring-Shaped MEMS-Based Piezoresistive Force Sensor for Cardiac Ablation Catheters". IEEE Sensors Journal 21, nr 22 (15.11.2021): 26042–49. http://dx.doi.org/10.1109/jsen.2021.3118298.
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Liu, Yan, Haijun Han, Yuming Mo, Xiaolong Wang, Huafeng Li i Jin Zhang. "A flexible tactile sensor based on piezoresistive thin film for 3D force detection". Review of Scientific Instruments 93, nr 8 (1.08.2022): 085006. http://dx.doi.org/10.1063/5.0083428.
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This paper presents a flexible tactile sensor with a compact structure based on a piezoresistive thin film and an elastomer for detecting three-dimensional (3D) force. The film contains four independent sensing cells, which were made using a type of piezoresistive ink and a specific pectinate conductive circuit pattern based on the flexible substrate to decrease the coupling effect. The elastomer with a spherical surface is bonded to the surface of the film and transfers the force to the sensing array. A model of 3D force detection based on the proposed sensor was established, and a prototype was designed and developed. Static and dynamic experiments were carried out, and the results show that the range of the prototype is 0–50 N in the z-axis and 0–6 N in the x-axis and y-axis, which with good static and dynamic performance, especially a low coupling effect, validates the mechanism of the proposed sensor and indicates that it has good potential application in robotic grasping.
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Lee, Da-Huei, Cheng-Hsin Chuang, Muhammad Omar Shaikh, Yong-Syuan Dai, Shao-Yu Wang, Zhi-Hong Wen, Chung-Kun Yen, Chien-Feng Liao i Cheng-Tang Pan. "Flexible Piezoresistive Tactile Sensor Based on Polymeric Nanocomposites with Grid-Type Microstructure". Micromachines 12, nr 4 (16.04.2021): 452. http://dx.doi.org/10.3390/mi12040452.
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Piezoresistive tactile sensors made using nanocomposite polymeric materials have been shown to possess good flexibility, electrical performance, and sensitivity. However, the sensing performance, especially in the low-pressure range, can be significantly improved by enabling uniform dispersion of the filler material and utilization of effective structural designs that improve the tactile sensing performance. In this study, a novel flexible piezoresistive tactile sensor with a grid-type microstructure was fabricated using polymer composites comprising multi-walled carbon nanotubes (MWCNTs) as the conductive filler and polydimethylsiloxane (PDMS) as the polymeric matrix. The research focused on improving the tactile sensor performance by enabling uniform dispersion of filler material and optimizing sensor design and structure. The doping weight ratio of MWCNTs in PDMS varied from 1 wt.% to 10 wt.% using the same grid structure-sensing layer (line width, line spacing, and thickness of 1 mm). The sensor with a 7 wt.% doping ratio had the most stable performance, with an observed sensitivity of 6.821 kPa−1 in the lower pressure range of 10–20 kPa and 0.029 kPa−1 in the saturation range of 30–200 kPa. Furthermore, the dimensions of the grid structure were optimized and the relationship between grid structure, sensitivity, and sensing range was correlated. The equation between pressure and resistance output was derived to validate the principle of piezoresistance. For the grid structure, dimensions with line width, line spacing, and thickness of 1, 1, and 0.5 mm were shown to have the most stable and improved response. The observed sensitivity was 0.2704 kPa−1 in the lower pressure range of 50–130 kPa and 0.0968 kPa−1 in the saturation range of 140–200 kPa. The piezoresistive response, which was mainly related to the quantum tunneling effect, can be optimized based on the dopant concentration and the grid microstructure. Furthermore, the tactile sensor showed a repeatable response, and the accuracy was not affected by temperature changes in the range of 10 to 40 °C and humidity variations from 50 to 80%. The maximum error fluctuation was about 5.6% with a response delay time of about 1.6 ms when cyclic loading tests were performed under a normal force of 1 N for 10,200 cycles. Consequently, the proposed tactile sensor shows practical feasibility for a wide range of wearable technologies and robotic applications such as touch detection and grasping.
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Li, Shuge, Pengju Zhao i Wencheng Sun. "Structural Design and Static Calibration of Six-axis Force/Torque Sensor". Journal of Physics: Conference Series 2557, nr 1 (1.07.2023): 012075. http://dx.doi.org/10.1088/1742-6596/2557/1/012075.
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Abstract A six-axis force/torque sensor is designed to solve the problems of the sensor with a resistance strain gauge. For instance, if the adhesive layer of the resistance strain gauge is not firm, the elastic sensing beam will have plastic deformation. The cylindrical conductive rubber is used as the sensing unit, which can detect force/torque by the change of the piezoresistive values. The units are arranged in a spatial eight-point staggered manner, which can reduce the dimensional coupling from the structure. The sensor static calibration is systematically analyzed and researched. The linear decoupling model of the measurement system that incorporating the Least Squares algorithm is established to reduce the dimensional coupling. The new type of sensor structure and static linear calibration algorithm proposed in this paper have good practical applications and popularization values.
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Huang, Kaiyan, Shuying Tong, Xuewei Shi, Jie Wen, Xiaoyang Bi, Alamusi Li, Rui Zou i in. "The Numerical and Experimental Investigation of Piezoresistive Performance of Carbon Nanotube/Carbon Black/Polyvinylidene Fluoride Composite". Materials 16, nr 16 (11.08.2023): 5581. http://dx.doi.org/10.3390/ma16165581.
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The composites with multiple types of nano-carbon fillers have better electrical conductivity and piezoresistive properties as compared with composites with a single type of nano-carbon fillers. As previously reported, the nano-carbon fillers with various aspect ratios, such as carbon nanotube (CNT) and carbon black (CB), have synergistic enhanced effects on the piezoresistive performance of composite sensors. However, most of the works that have been reported are experimental investigations. The efficient and usable numerical simulation investigation needs to be further developed. In this study, based on an integrated 3D statistical resistor network model, a numerical simulation model was created to calculate the piezoresistive behavior of the CNT/CB/ Polyvinylidene Fluoride (PVDF) composite. This model also takes into account the tunneling effect between nearby nano-fillers. It is found from numerical simulation results that the piezoresistive sensitivity of composite simulation cells can be influenced by the fraction of CNT and CB. In the case that the CNT content is 0.073 wt.%, the best force-electrical piezoresistive sensitivity can be achieved when the CB loading is up to 0.2 wt.%. To verify the validity of the simulation model, the previous experimental investigation results are also compared. The experimental results confirm the validity of the model. The investigation is valuable and can be utilized to design a strain sensor for this nano-composite with increased sensitivity.
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Zhang, Peng, Yucheng Chen, Yuxia Li, Yun Zhao, Wei Wang, Shuyuan Li i Liangsong Huang. "Flexible Piezoresistive Sensor with the Microarray Structure Based on Self-Assembly of Multi-Walled Carbon Nanotubes". Sensors 19, nr 22 (15.11.2019): 4985. http://dx.doi.org/10.3390/s19224985.
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High-performance flexible pressure sensors have great application prospects in numerous fields, including the robot skin, intelligent prosthetic hands and wearable devices. In the present study, a novel type of flexible piezoresistive sensor is presented. The proposed sensor has remarkable superiorities, including high sensitivity, high repeatability, a simple manufacturing procedure and low initial cost. In this sensor, multi-walled carbon nanotubes were assembled onto a polydimethylsiloxane film with a pyramidal microarray structure through a layer-by-layer self-assembly system. It was found that when the applied external pressure deformed the pyramid microarray structure on the surface of the polydimethylsiloxane film, the resistance of the sensor varied linearly as the pressure changed. Tests that were performed on sensor samples with different self-assembled layers showed that the pressure sensitivity of the sensor could reach − 2.65 kPa − 1 , which ensured the high dynamic response ability and the high stability of the sensor. Moreover, it was proven that the sensor could be applied as a strain sensor under the tensile force to reflect the stretching extent or the bending object. Finally, a flexible pressure sensor was installed on five fingers and the back of the middle finger of a glove. The obtained results from grabbing different weights and different shapes of objects showed that the flexible pressure sensor not only reflected the change in the finger tactility during the grasping process, but also reflected the bending degree of fingers, which had a significant practical prospect.
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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, Gang, Lei Li, Xiao Feng Zhao, Dian Zhong Wen i Yang Yu. "The Vibration Pickup of Micro-Pump Diaphragm Based on MEMS Technology Design". Key Engineering Materials 609-610 (kwiecień 2014): 837–41. http://dx.doi.org/10.4028/www.scientific.net/kem.609-610.837.
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This paper designs a micro-pump silicon diaphragm vibration pickup sensor. In this newsensor which is based on piezoresistive effect, four MOSFETs with nc-Si/c-Si heterojunction drainand source are manufactured on the surface of silicon wafer by using the technique of CMOS andPECVD, at edge of <100> orientation of the N-type silicon diaphragm rectangle, and using MEMStechnology, the back of the four MOSFETs device silicon substrate processed into silicon cup, whichconstitutes the vibration pickup sensor. The micro-pump silicon diaphragm vibration pickup sensornot only has all the advantages of conventional force sensitive resistance vibration pickup sensor, butalso has the advantages of small temperature drift, high detection precision, and it can satisfy themicro-pump silicon diaphragm vibration requirements.
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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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Chadwick, K. M., D. J. DeTurris i J. A. Schetz. "Direct Measurements of Skin Friction in Supersonic Combustion Flow Fields". Journal of Engineering for Gas Turbines and Power 115, nr 3 (1.07.1993): 507–14. http://dx.doi.org/10.1115/1.2906737.
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An experimental investigation was conducted to measure skin friction along the chamber walls of supersonic combustors. A direct force measurement device was used to measure simultaneously an axial and a transverse component of the small tangential shear force passing over a nonintrusive floating element. This measurement was made possible with a sensitive piezoresistive deflection sensing unit. The floating head is mounted to a stiff cantilever beam arrangement with deflection due to the flow on the order of 0.00254 mm (0.0001 in). This allowed the instrument to be a nonnulling type. A second gage was designed with active cooling of the floating sensor head to eliminate nonuniform temperature effects between the sensor head and the surrounding wall. The key to this device is the use of a quartz tube cantilever with piezoresistive strain gages bonded directly to its surface. A symmetric fluid flow was developed inside the quartz tube to provide cooling to the backside of the floating head. Tests showed that this flow did not influence the tangential force measurement. Measurements were made in three separate combustor test facilities. Tests at NASA Langley Research center consisted of a Mach 3.0 vitiated air flow with hydrogen fuel injection at Pt = 500 psia (3466 kPa) and Tt = 3000 R (1667 K). Two separate sets of tests were conducted at the General Applied Science Laboratory (GASL) in a scramjet combustor model with hydrogen fuel injection in vitiated air at Mach = 3.3, Pt = 800 psia (5510 kPa), and Tt = 4000 R (2222 K). Skin friction coefficients between 0.001–0.005 were measured dependent on the facility and measurement location. Analysis of the measurement uncertainties indicate an accuracy to within ± 10–15 percent of the streamwise component.
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Xiong, Zhuang, Benjamin Walter, Estelle Mairiaux, Marc Faucher, Lionel Buchaillot i Bernard Legrand. "Piezoresistive Ring-Shaped AFM Sensors with Pico-Newton Force Resolution". International Journal of Intelligent Mechatronics and Robotics 3, nr 1 (styczeń 2013): 38–52. http://dx.doi.org/10.4018/ijimr.2013010104.
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A new concept of Atomic Force Microscope (AFM) oscillating probes using electrostatic excitation and piezoresistive detection is presented. The probe is characterized by electrical methods in a vacuum chamber and by mechanical methods in air. The frequency-mixing measurement technique is developed to reduce the parasitic signal level. These probes resonant in the 1MHz range and the quality factor is measured about 53000 in vacuum and 3000 in air. The ring probe is mounted onto a commercial AFM set-up and the surface topography of PMMA sample (2 µm square) is obtained. The force resolution deduced from the measurements is about 10 pN/Hz0.5.
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Hong, Wonki, Jungmin Lee i Won Gu Lee. "A Dual-Padded, Protrusion-Incorporated, Ring-Type Sensor for the Measurement of Food Mass and Intake". Sensors 20, nr 19 (1.10.2020): 5623. http://dx.doi.org/10.3390/s20195623.
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Dietary monitoring is vital in healthcare because knowing food mass and intake (FMI) plays an essential role in revitalizing a person’s health and physical condition. In this study, we report the development of a highly sensitive ring-type biosensor for the detection of FMI for dietary monitoring. To identify lightweight food on a spoon, we enhance the sensing system’s sensitivity with three components: (1) a first-class lever mechanism, (2) a dual pad sensor, and (3) a force focusing structure using a ring surface having protrusions. As a result, we confirmed that, as the food arm’s length increases, the force detected at the sensor is amplified by the first-class lever mechanism. Moreover, we obtained 1.88 and 1.71 times amplification using the dual pad sensor and the force focusing structure, respectively. Furthermore, the ring-type biosensor showed significant potential as a diagnostic indicator because the ring sensor signal was linearly proportional to the food mass delivered in a spoon, with R2 = 0.988, and an average F1 score of 0.973. Therefore, we believe that this approach is potentially beneficial for developing a dietary monitoring platform to support the prevention of obesity, which causes several adult diseases, and to keep the FMI data collection process automated in a quantitative, network-controlled manner.
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KUSANO, Tadamasa, Takeshi OKUYAMA i Mami TANAKA. "Study on characteristics evaluation of ring-type fingertip force sensor in various finger postures". Proceedings of the Conference on Information, Intelligence and Precision Equipment : IIP 2018 (2018): 1B12_1. http://dx.doi.org/10.1299/jsmeiip.2018.1b12_1.
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Toyama, Shigeru, Satoshi Shirogane, Takashi Nakamura, Kenta Watanabe i Kazuhiro Hara. "Development of Thin Shear Force Sensor Aimed at Improving QOL for Persons with Disabilities". Proceedings 2, nr 13 (14.12.2018): 704. http://dx.doi.org/10.3390/proceedings2130704.
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We have been developing a sheet type shear force sensor. It has a unique structure consisting of two flexible electrode films, a rubber ring, and a liquid electrolyte. One of the electrode films has a central electrode and the other film had four symmetrically arranged electrodes. The diameter of the sensor head was 10 mm and the thickness was about 0.7 mm. We also developed mobile measurement circuit and software for the computer. This system can handle up to four sensors simultaneously. Furthermore, we obtained experimental data by attaching the sensor to a human body using a double‐sided adhering tape.
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OKUYAMA, Takeshi, Masaaki Mita i Mami TANAKA. "Study on measurement of tendon indentation by a finger ring type sensor for measuring fingertip force". Proceedings of Mechanical Engineering Congress, Japan 2020 (2020): J16314. http://dx.doi.org/10.1299/jsmemecj.2020.j16314.
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Shilova, Irina. "PHYSICAL-MATHEMATICAL MODEL OF BENDING FIBER-OPTIC SENSOR OF FORCE". Bulletin of Bryansk state technical university 2020, nr 1 (17.01.2020): 18–27. http://dx.doi.org/10.30987/1999-8775-2020-2020-1-18-27.
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There is presented a model of an explosion-proof, jam-resistant under conditions of high level electromagnetic fields fiber-optical sensor of tensile force on the basis of a fiber-optical transformer of movements in which a distinctive peculiarity is an application of loss changes in radiation spreading in sensitive elements as ring loops deformed elliptically of multi-mode fiber light-guides forming a bundle that allows using a diode as a radiation source installed without a special alignment device.
It is defined that a peculiarity of bending fiber-optical transformers of movement of a successive-parallel type is that in separate areas of rings a radius of curvature increases at the expense of deformation and the losses of radiation in these areas decrease, and in other ones this radius decreases that results in the increase of losses of the radiation spreading by light-guides. Overall losses directed at radiation in light-guides increase lineally with the increase of movement. There is carried out a choice of the optimum number of rings of a sensitive element and a choice of “source-radiation receiver” for obtaining a linear calibration characteristic of the sensor. It is shown that varying the number of coils in the bending fiber-optical transformer it is possible to change a range of movements measured ind a form of calibration characteristic of a transformer.
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Li, Y., G. W. Yang, Q. Z. Meng i K. Z. Wang. "Research on dynamic characteristics of gun turret under launching load". Journal of Physics: Conference Series 2478, nr 9 (1.06.2023): 092009. http://dx.doi.org/10.1088/1742-6596/2478/9/092009.
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Abstract The purpose of this study is to further study the dynamic characteristics of gun turret under firing load. Firstly, the relative motion between inner ring and outer ring was decomposed into axial translational motion, radial translational motion and rotational freedom in two orthogonal radial planes in order to solve the problem of large number of ball bearings and complex contact calculation in the actual structure of turret ring. Then, the equivalent dynamic mathematical model of turret ring was established. Based on the finite element method, the turret ring is equivalent to Bushing with body-body connection type, Multi-point constraints algorithm and Deformable Behavior attribute. The equivalent stiffness of the turret ring is set as linear stiffness, and the turret dynamic model is established. The dynamic response simulation of the turret under the action of firing load was carried out. The acceleration sensor was arranged at the left trunnion position of the turret, and the acceleration generated by the transient force during firing was measured at the left trunnion position. The results showed that the test value of the acceleration at the left trunnion position was 1304.38m /s2,the simulation value of the turret dynamic model is 1425 m/s2, and the error is 8.46%, which verifies the accuracy of the turret dynamic model and indicates that the turret dynamic model can reflect the dynamic characteristics of the turret well.
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Middleton, S. D., P. J. Jenkins, A. Y. Muir, R. E. Anakwe i J. E. McEachan. "Variability in local pressures under digital tourniquets". Journal of Hand Surgery (European Volume) 39, nr 6 (3.06.2013): 637–41. http://dx.doi.org/10.1177/1753193413492059.
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The UK National Patient Safety Agency issued a rapid response report in 2009 following reports of complications related to digital tourniquet use and inadvertent retention. In their guidance, they recommend the use of CE marked digital tourniquets and advise against the use of surgical gloves. There are a number of different commercially available non-pneumatic digital tourniquets, but little clear data relating to their comparable physical properties, clinical efficacy or safety. The aim of this study was to investigate the variability of pressures exerted by non-pneumatic digital tourniquets. A Tekscan FlexiForce® force sensor was used to measure applied force and to calculate the surface pressures under: the Toe-niquet™; T-Ring™ and surgical glove ‘roll down’ tourniquets in finger models. The lowest mean pressures were produced by the larger glove sizes (size 8) (25 mmHg), while the highest pressures were produced by the Toe-niquet (1560 mmHg). There was a significant overall difference in pressures exerted under tourniquets when comparing tourniquet type ( p<0.001) and finger size ( p<0.001) with these techniques. It is difficult to anticipate and regulate pressures generated by non-pneumatic tourniquets. Safe limits for application time and surface pressures are difficult to define. Further work is required to model the pressure effects of commercially available digital tourniquets and to identify which are most effective but safe.
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Romero-Soto, Fabian Oswaldo, Mohammad Mahdi Aeinehvand, Marc Madou i Sergio Omar Martinez-Chapa. "(Digital Presentation) An Electrochemical Sensor in a Disc for Real-Time PCR Assisted with Thermal Convective Flow". ECS Meeting Abstracts MA2022-02, nr 61 (9.10.2022): 2230. http://dx.doi.org/10.1149/ma2022-02612230mtgabs.
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Nowadays, the polymerase chain reaction (PCR) has extensively adapted to microfluidic devices for several features such as the low consumption of reagents and sample, portability, high-throughput, and low fabrication costs [1]. The reduction of the amplification time has been a relevant parameter since the invention of the PCR, where rapid microfluidic PCR is especially preferred for the detection of infectious diseases [1,2]. The continuous-flow-based PCR is a type of microfluidic PCR that proposes the mobilization of the PCR mixture through a microchannel with different fixed temperature zones to achieve the required thermal-cycling [3]. This approach has smaller thermal inertia because only the PCR mixture needs to be heated and cooled instead of the entire microfluidic device. The continuous-flow approach allows rapid-thermal cycling with lower power consumption and, therefore, reduces the overall amplification time. The Lab-on-a-disc, or centrifugal microfluidic platform, has adapted the continuous-flow PCR by utilizing the flow generated by thermal convection in a ring-structured microchannel [4]. During spinning, embedded heaters in the bottom of the CD heat specific section of the microchannel (see Figure 1) at a fixed temperature and, subsequently, create a natural convection flow in the PCR mixture and move through the microchannel. The centrifugal-assisted thermal convection (CATC) technique not only enables the recirculation pathway for the continuous-flow PCR but overcomes the unidirectional nature of centrifugation force on the CD. Despite the advantage of rapid PCR on Lab-on-a-Disc, the CATC technique lacks the implementation of a detection method with high sensitivity and resolution, aiming for a fully integrated microfluidic platform. Electrochemical detection can provide fast responses with minimum power consumption for miniaturized devices. This work proposes the integration of an electrochemical sensor to the CATC technique in a circular microchannel for the real-time monitoring of DNA amplification. The electrochemical sensor consists of interdigitated gold electrodes located above the ring microchannel to quantify the amplicon concentration after each cycle mediated by the intercalation of Methylene Blue between the newly-generated DNA (see figure 1A). The characterization of the sensor is performed through voltammetric techniques such as cyclic voltammetry (CV) and linear sweep voltammetry (LSV), where the latter is utilized for amplicon quantification. To optimize the CATC technique combined with the electrochemical sensor, a COMSOL simulation is performed to improve the amplification ratio and amplification time in the CD by analyzing the microchannel geometry and flow rate (see figure 1B). Both the thermal control for the thermal-assisted microchannel and the electrochemical sensor are powered and controlled via the “electrified Lab-on-a-Disc” (eLoaD) board [5] (see figure 1C). [1] Y. Zhang, P. Ozdemir, Anal. Chim. Acta 638 (2009) 115–125. [2] X. Dong, L. Liu, Y. Tu, J. Zhang, G. Miao, L. Zhang, S. Ge, N. Xia, D. Yu, X. Qiu, TrAC - Trends Anal. Chem. 143 (2021) 116377. [3] M.B. Kulkarni, S. Goel, Eng. Res. Express 2 (2020). [4] M. Saito, K. Takahashi, Y. Kiriyama, W.V. Espulgar, H. Aso, T. Sekiya, Y. Tanaka, T. Sawazumi, S. Furui, E. Tamiya, Anal. Chem. 89 (2017) 12797–12804. [5] S.M. Torres Delgado, J.G. Korvink, D. Mager, Biosens. Bioelectron. 117 (2018) 464–473. Figure 1
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Mohanraj, Thangamuthu, Mohammad Uddin i Sevagoundanoor Karuppusamy Thangarasu. "Review on sensor design for cutting force measurement". Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering, 14.06.2022, 095440892211062. http://dx.doi.org/10.1177/09544089221106264.
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The measurement of cutting force is one of the key factors in determining the tool condition and improving machine reliability. Therefore, the cutting force measurement becomes crucial to improve the machining process. The cutting force can be measured with piezoelectric as well as piezoresistive transducers. The force measuring transducers with later ones are cost-effective and can be easily installed in any small/medium-scale enterprise. For this approach, the selection of sensing elements is essential. The various mechanical ring elements were used for sensing the deformation. The low-cost device can be affordable in small-scale industries. Along with cutting force, it is suggested to measure the vibration signals to analyze the machining dynamics of the process. The salient features and diverse force measuring transducers were discussed in this article. This paper aims to briefly review the existing design and performance of dynamometers used in modern manufacturing.
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Rizal, Muhammad, Jaharah A. Ghani, Husni Usman, Muhammad Dirhamsyah i Amir Zaki Mubarak. "Development and testing of a stationary dynamometer using cross-beam-type force-sensing elements for three-axis cutting force measurement in milling operations". Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 23.06.2023. http://dx.doi.org/10.1177/09544054231182175.
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This study focused on the development and testing of a stationary dynamometer using force-sensing elements capable of measuring three axes of cutting force during milling operations. The force-sensing element was based on the Maltese cross-beam concept but has been improved and modified to increase sensitivity and reduce interference or cross-talk error. A Finite element analysis was conducted to study strain distribution and determine sensor positions in the force-sensing element. By using four force-sensing elements and several piezoresistive strain sensors, a stationary dynamometer prototype was constructed. A series of calibration tests were performed to evaluate the dynamometer’s sensitivity, linearity, hysteresis, and repeatability over three orthogonal axes. The dynamometer’s dynamic features and functionality for milling applications were examined through modal analysis and real milling tests. Additionally, the end-milling and slot-milling cutting force values were compared to those of a reference dynamometer (Kistler 9129AA). Overall, the experimental results indicated that the proposed stationary dynamometer is a reliable and accurate alternative for measuring cutting force during machining operations and other force measurements.
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Fullenkamp, Dominic E., Seyong Oh, Yoonseok Park, Ivana A. Chychula, Cory W. Holgren, Jodi L. Curtin, Alexis R. Demonbreun, John A. Rogers i Elizabeth M. McNally. "Abstract 11979: Direct Assessment of Engineered Heart Tissue Field Potential and Contraction Dynamics Using Flexible Electronics Technology". Circulation 146, Suppl_1 (8.11.2022). http://dx.doi.org/10.1161/circ.146.suppl_1.11979.
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Introduction: Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) enable the study of human heart disease in a dish. However, when cultured as cells on plastic, these 2D models are immature and exhibit non-physiologic outputs. When cultured as engineered heart tissues (EHTs or 3D models), hiPSC-CMs display a more mature gene and protein profile. Although multielectrode array (MEA) platforms have been applied to 2D cultures to study the electrical properties of hiPSC-CMs, a similar approach has been lacking for EHTs. We now took advantage of technological advances in flexible electronics to create a 3D platform that allows continuous transduction of field potential and strain of human EHTs. Methods and Results: Using microfabrication techniques adapted from the semiconductor industry, custom ring-shaped flexible electronics constructs were created with 6 support posts. Each post included a microelectrode for recording electrophysiological information and a piezoresistive strain sensor for monitoring EHT contraction dynamics. These were integrated onto a flexible biocompatible polyimide support. hiPSCs were differentiated into hiPSC-CMs, and EHTs were generated by seeding 500,000 cells composed of 90% hiPSC-CMs and 10% human cardiac fibroblasts into a collagen matrix and deposited in the ring-shaped polydimethylsiloxane (PDMS) molds. Tissues were condensed over 7 days and then were transferred onto the flexible electronic scaffolds. Tissues remodeled for ~30 days and then were analyzed for contractile properties. Direct tissue stimulation and field potential measurements were obtained in real time using an Intan RHS stimulation recording system. Simultaneous recording of force of contraction relied on a calibrated Wheatstone bridge circuit. EHTs from hiPSC-CMs displayed appropriate contractile responses to pharmacologic agents. Conclusion: Although EHTs improve hiPSC-CM models by improving cellular maturity, it has been challenging to measure physiological outcomes. We now developed a prototype that simultaneously provides electrophysiologic and contractility characterization in real time of human EHTs.
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Mariasiu, Florin. "Benchmark tests for a Formula SAE Student car prototyping". Open Engineering 1, nr 4 (1.01.2011). http://dx.doi.org/10.2478/s13531-011-0047-0.
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AbstractAerodynamic characteristics of a vehicle are important elements in its design and construction. A low drag coefficient brings significant fuel savings and increased engine power efficiency. In designing and developing vehicles trough computer simulation process to determine the vehicles aerodynamic characteristics are using dedicated CFD (Computer Fluid Dynamics) software packages. However, the results obtained by this faster and cheaper method, are validated by experiments in wind tunnels tests, which are expensive and were complex testing equipment are used in relatively high costs. Therefore, the emergence and development of new low-cost testing methods to validate CFD simulation results would bring great economic benefits for auto vehicles prototyping process. This paper presents the initial development process of a Formula SAE Student race-car prototype using CFD simulation and also present a measurement system based on low-cost sensors through which CFD simulation results were experimentally validated. CFD software package used for simulation was Solid Works with the FloXpress add-on and experimental measurement system was built using four piezoresistive force sensors FlexiForce type.
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Faust, Leon Marcel, Alexander Martin Keppler, Eduardo Suero, Johannes Gleich, Leonard Lisitano, Wolfgang Böcker, Carl Neuerburg i Daniel Pfeufer. "The grade of instability in fragility fractures of the pelvis correlates with impaired early mobilization". European Journal of Trauma and Emergency Surgery, 13.03.2022. http://dx.doi.org/10.1007/s00068-022-01933-y.
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Abstract Purpose This study aimed to investigate whether gait patterns of patients with fragility fractures of the pelvis (FFP) comply with the grade of fracture instability, defined by radiological patterns. Patients and methods This prospective, single-center, observational study included 39 patients with an FFP. Gait analysis was performed with a wearable insole force sensor (Loadsol® by Novel, Munich, Germany) 4–7 days after admission. Patients were divided in two groups: Group A included FFP type 1 fractures, which affect the anterior pelvic ring only, Group B contained FFP type 2–4 fractures with an involvement of the posterior pelvic ring. Primary outcome parameter was the FTI ratio (force–time integral (N*s)). Results The mean age was 85.08 years (SD ± 6.45), 94.9% (37/39) of the patients were female. The most common fracture type was an FFP 2b (64.1%, 25/39). Group A showed a significantly higher FTI ratio (45.12%, SD ± 4.19%) than Group B (38.45%, SD ± 5.97%, p = 0.002). Further, a significant correlation of the FTI ratio and the average (r = 0.570, p < 0.001) and maximum (r = 0.394, p = 0.013) peak force was observed. Conclusion The gait pattern of patients with an FFP type 2–4 was more imbalanced than of patients with an FFP type 1 fracture. These findings match with the radiological classification of FFP, which indicates higher instability, when the posterior pelvis is affected. Gait analysis might offer earlier functional diagnostics and may accelerate the treatment decision with shorter periods of immobility in future. Especially in cross-border cases, early gait analysis could be beneficial to clarify the indication for or against surgery.
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Khalaf, Jamal Kheiro, i Diyar Sadiq. "Fabrication of pyramid-shaped gold tip for adiabatic nanofocusing of surface plasmon polaritons". Journal of Vacuum Science & Technology B 41, nr 5 (3.08.2023). http://dx.doi.org/10.1116/6.0002505.
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Scattering-type scanning near-field optical microscopy based on adiabatic nanofocusing of surface plasmon polaritons (SPPs) is a powerful technique that can achieve free-background nanoscale optical resolution of material. However, the performance of the propagated confined modes strongly depends on the characteristic structure of the probe. Although the metallic pyramid structure provides excellent tightly confined modes, however, it is challenging to realize the required pyramid geometry. Here, we propose a simple method for fabricating a reproducible and controllable gold pyramid-shaped tip. The produced pyramid-shaped tips were made by electrochemical etching and by applying a pulse wave to the system. From a systematic study, we found that the key factor of fabrication of desired tip geometry is based on the platinum (Pt) wire shapes. Traditional circular-shaped platinum ring electrodes are used for gold tip fabrication in an electrochemical etching. In our method, we bent the Pt wire into a triangular shape as the electrode for the etching process. The influence of the geometrical ring shapes on the fabrication of the Au tip structure is investigated. The gold tip structure was optimized by controlling the Pt ring shape, and the desired pyramid-shaped gold tip was achieved with a yield of 70%. The obtained etched pyramid-shaped tips were then mounted along the side of one of the arms of a quartz tuning fork force sensor to test their performance for shear-force topographical image and for guiding SPPs along the pyramid wedge based on adiabatic nanofocusing microscopy. The result shows topographical images of indium tin oxide with a spatial resolution smaller than 20 nm. Furthermore, we experimentally demonstrate the generation of the SPPs that propagated adiabatically along the wedge of an appropriate fabricated pyramid-shaped tip toward a nanometer-size spot at the tip apex. The demonstration of this method strongly suggests that the obtained pyramid-shaped tip will enable new experiments probing the dynamics of optical excitations of individual metallic, semiconducting, and magnetic nanostructures.
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Okumura, Yasuo, Benhur D. Henz, Susa B. Johnson i Douglas L. Packer. "Abstract 3223: Feasibility and Safety of the Integrated 3D Image and Contact Force-Guided Ablation for Atrial Fibrillation with the Hansen Robotic Catheter Sheath System". Circulation 116, suppl_16 (16.10.2007). http://dx.doi.org/10.1161/circ.116.suppl_16.ii_725-a.
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Background: Current technologies to fully “register” surrogate maps onto 3D CT (CartoMerge, NavxMerge) or 3D ICE images (CartoSound) have emerged to guide ablation. The feasibility of navigation with the Hansen Robotic Catheter Sheath System (HRCS) has also been reported. Integrated 3D Image and contact force sensor with this robotic system may allow for feasibility and safety for guiding complex anatomic-based ablation. Methods: Circumferential pulmonary vein (PV) ablation with the robotic system guided by integrated 3D images (CartoMerge, NavxMerge or CartoSound) (n=3), were done and compared to manual manipulation guided by the integrated 3D images (CartoSound) (n=8). Each ablation was performed using contact force ranges of 10 –20 grams (20W, 17 ml/min flow, 30 seconds). Accuracy of PV ablation was assessed by comparing distance from the PV ostia (specific 4 sites) to the ablative points on the 3D image structures, and the corresponding distances of the actual ablative lesions at pathologic exam. Results: Using three integrated 3D image systems, circumferential PV ablation was successfully guided in 6 PVs (3 RSPVs and 3 LSPVs) with the robotic system. During all ablations with contact forces of 10 –20 grams, no impedance rises, pops or type 2 microbubbles were seen. Accuracy of the PV ablation was 0.22±0.84 mm (range 0 –2). The PV rings were 100% circumferential by electroanatomic mapping, yielding an 86±7% (range 80 –98%) uninterrupted circumferential ablative ring around each PV with 1.1 ± 0.4 gaps (3.0 ± 0.9 mm). These resulting parameters were equal to those in the integrated 3D image-based manual navigation (Accuracy: 0.5±0.9 (range 0 –2.5) mm, Gaps:1.3 ± 0.9 ( 2.6 ± 0.9 mm), circumferential lesions 88 ± 10% (range 70 –100). Conclusions: This feasibility study demonstrated successful integrated 3D image and contact force-guided robotic ablation. Contact sensor guided 3D volume construction and real time 3D images accurately replicated atrial and venous anatomy, resulting in successful circumferential ablation.
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Dareka, Madhavi Sharad, i B. M. Praveen. "Effects of Heat Treatment in Air Atmosphere on Dip Coating Deposited CdS Thin Films for Photo Sensor Applications". Journal of Modern Nanotechnology, 20.04.2023. http://dx.doi.org/10.53964/jmn.2023002.
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Objective: In this report, photo sensitive materials with enhanced charge carriers have been prepared using dip coating technique. Methods: Cadmium sulphide (CdS) is N-type semiconductor compound belonging to II-VI group. CdS nanoparticles were synthesized using non-aqueous chemical method and characterized by ultraviolet-visible (UV-Vis) absorption spectroscopy, photoluminescence (PL) and transmission electron microscopy. CdS films were deposited on fluorine doped tin oxide (FTO) glass slides using dip coating method at different dip times and heat treated in air and analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis by X-rays (EDAX), mapping and atomic force microscopy (AFM). Results: Quantum confinement effect was observed in UV-Vis absorption spectra of CdS nanoparticles. Quenching of luminescence intensity and blue shift at smaller wavelengths were observed in PL spectra. Presence of highly dense rectangular shaped grains in CdS films and increment in particle sizes with increase in dip time were shown by AFM images. Selected area electron diffraction images showed ring patterns indicating polycrystalline nature of CdS nanoparticles. Increase in crystallite size and decrease in crystal defects by heat treatment in air and increment in grain size with increase in dip time were shown by SEM images. XRD analysis of CdS films showed polycrystalline nature. Conclusion: In previous work, preparation of dip coating deposited CdS films on FTO glass substrates for optoelectronic device applications such as photo sensors has not been reported. In this study, I-V characteristics of heterojunctions under dark and illumination conditions were discussed. Experimental results obtained in our study and their comparison with previous reports were also discussed.