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Pantzare, Sandra, i Elin Wollert. "Wireless Piezoelectric Horse Sensor System". Thesis, Linköpings universitet, Fysik och elektroteknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-150152.
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The domestication of horses took place at least 2000 BCE. Since then, horses have been used for transportation, agricultural work and even for warfare. Today, horses have been bred into world athletes, used worldwide in equestrian sports. However, these explosive performance horses present characteristics that make them prone to injuries leading to lameness. According to the insurance company Agria, more than 50 % of all reported injuries on horses in Sweden each year, are related to lameness. Using more objective analysing methods can lead to earlier detection and decrease the occurrence of this kind of injuries. In this Master’s degree project, a horse sensor system was proposed, designed and manufactured as a first prototype. The system consists of a force measuring device and an external reader. The force measuring sensor itself is a piezoelectric printed sensor. The force measuring device senses, acquires and transmits the raw data to the external reader. The focus of this project was on the hardware- and software development of the force measuring device and the software development for the external reader. To develop and verify the algorithms, as well as the entire system concept, the CC1352R1 Launchpad from Texas Instruments was used. The first results have indicated that the developed hardware and software of the force measuring device performs as expected. Also, important conclusions were drawn for both the force measuring device and the external reader. E.g., the force measuring device should fit the required physical dimension of the hoof sole, and the algorithms of the external reader should be improved in terms of data flow and memory usage. To conclude, the project is a challenging application making use of modern wireless sensor technology and printed electronics.
2
Sharapov, V. M., K. V. Bazilo i R. V. Trembovetskaya. "Electro-Acoustic System with Piezoelectric Sensor". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/41006.
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Piezoelectric transducers are widely used in electro-acoustic, hydroacoustic,
ultrasonic, medical and measuring techniques, security and control
systems. One of the main characteristics of the piezoelectric transducers is
operation frequency band. Despite the fact that it is used to be expanded,
narrowband piezoelectric transducers also can be used. In particular, the
fields of application of piezoelectric transducers are narrowband alarm
systems, for example, glass breakage detectors [1].
3
Ahmadi, Mehdi. "Energy Harvesting Wireless Piezoelectric Resonant Force Sensor". Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc407829/.
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The piezoelectric energy harvester has become a new powering option for some low-power electronic devices such as MEMS (Micro Electrical Mechanical System) sensors. Piezoelectric materials can collect the ambient vibrations energy and convert it to electrical energy. This thesis is intended to demonstrate the behavior of a piezoelectric energy harvester system at elevated temperature from room temperature up to 82°C, and compares the system’s performance using different piezoelectric materials. The systems are structured with a Lead Magnesium Niobate-Lead Titanate (PMN-PT) single crystal patch bonded to an aluminum cantilever beam, Lead Indium Niobate-Lead Magnesium Niobate-Lead Titanate (PIN-PMN-PT) single crystal patch bonded to an aluminum cantilever beam and a bimorph cantilever beam which is made of Lead Zirconate Titanate (PZT). The results of this experimental study show the effects of the temperature on the operation frequency and output power of the piezoelectric energy harvesting system. The harvested electrical energy has been stored in storage circuits including a battery. Then, the stored energy has been used to power up the other part of the system, a wireless resonator force sensor, which uses frequency conversion techniques to convert the sensor’s ultrasonic signal to a microwave signal in order to transmit the signal wirelessly.
4
Zhang, Ruizhi. "ARTERIAL WAVEFORM MEASUREMENT USING A PIEZOELECTRIC SENSOR". VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/126.
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This study aims to develop a new method to monitor peripheral arterial pulse using a PVDF piezoelectric sensor. After comparing different locations of sensor placement, a specific sensor wrap for the finger was developed. Its composition, size, and location make it inexpensive and very convenient to use. In order to monitor the effectiveness of the sensor at producing a reliable pulse waveform, a monitoring system, including the PZT sensor, ECG, pulse-oximeter, respiratory sensor, and accelerometer was setup. Signal analysis from the system helped discover that the PZT waveform is relative to the 1st derivative of the artery pressure wave. Also, the system helped discover that the first, second, and third peaks in PZT waveform represent the pulse peak, inflection point, and dicrotic notch respectively. The relationship between PZT wave and respiration was also analyzed, and, consequently, an algorithm to derive respiratory rate directly from the PZT waveform was developed. This algorithm gave a 96% estimating accuracy. Another feature of the sensor is that by analyzing the relationship between pulse peak amplitude and blood pressure change, temporal artery blood pressure can be predicted during Valsalva maneuver. PZT pulse wave monitoring offers a new type of pulse waveform which is not yet fully understood. Future studies will lead to a more broadly applied use of PZT sensors in cardiac monitoring applications.
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Holmes, J. E. "Novel piezoelectric structures for sensor and actuator applications". Thesis, University of Birmingham, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399477.
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Mika, Bartosz. "Design and testing of piezoelectric sensors". [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-1565.
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Theaker, Brenden John. "Volatile Sensing Using Coated Piezoelectric Quartz Crystal Sensor Arrays". Thesis, Teesside University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518736.
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Agyemang, Duah Joseph Agyemang Duah. "A PIEZOELECTRIC POWERED BLUETOOTH LOW ENERGY TEMPERATURE SENSOR PLATFORM". University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1533124081986125.
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Tharakan, Zacharia. "Fabrication and Characterization of Piezoelectric Zinc Oxide Nanowire Sensor". OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2268.
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AN ABSTRACT OF THE THESIS OF ZACHARIA THARAKAN, for the Master of Science degree in BIOMEDICAL ENGINEERING, presented on 11/06/17, at Southern Illinois University Carbondale. TITLE: FABRICATION AND CHARACTERIZATION OF PIEZOELECTRIC ZINC OXIDE NANOWIRE SENSOR MAJOR PROFESSOR: Dr. Farhan Chowdhury The biosensor field is rapidly accelerating in recent years. Among many types of biosensors available today, piezoelectric (PZT) class of materials are becoming very popular. In this thesis, Zinc Oxide nanowire PZT biosensor was fabricated and characterized to detect the presence of fungi which has some huge economic implications in US agriculture industry. Zinc Oxide nanowires were synthesized in a mass scale via wet solution method in a controlled temperature and growth environment. Different substrates including glass, indium tin oxide, and gold coated silicon substrates were utilized to grow the nanowires followed by layering with silane and subsequently etching them. The results show that the nanowires were grown homogenously on gold coated silicon wafers with cylindrical structures. The ideal morphology of the nanowires was found to be dependent on: incubation time, incubation temperature, and substrate material. Substrate catalyst was also varied from Au & Pd to pure Au which showed significant improvement in producing the nanowires. A systematic variation of hours was implemented from: 3, 5, 7, 9, 11, and 13 hours. Zinc Oxide nanowire features such as length, diameter, and aspect ratio were quantified through SEM micrographs. Linear increase in height, diameter, and aspect ratio was observed up to 13 hours along with density. The optimal condition for nanowire growth was determined at: 80 °C and 5 hours. Energy dispersive spectroscopy aided in generating presence of specific elements on the biosensor. Raman helps in verifying chemical composition of the device. Both Raman and EDS spectroscopy aided in enhancement and individualization of the biosensor at different proposed parameters. Keithley readings represented series of current-voltage (I-V) measurements under different forward biased voltages. The response of nanowires from these I-V measurements show a diode-like response. Next, nanowire displacement patterns of fungi, Fusarium proliferatum (F. proliferatum) were studied by I-V measurements. When I-V measurements were conducted on PZT nanowires in the presence of F. proliferatum a strong association from microbe attachment and growth was observed showing an increase in switch-on voltage with a 2V sweep. It is speculated that the observed high resistance is a result of mechanical movement of fungi on the piezoelectric device. Future studies will be designed to investigate this phenomenon. These results indicate that by simply reading the characteristic current-voltage measurement, one can better evaluate microbe pattern of displacement and maturation. Future application of this nanowire platform can characterize distinct displacement signature of disease carrying organism much more efficiently.
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Dhayal, Vandana Sultan Singh. "Exploring Simscape™ Modeling for Piezoelectric Sensor Based Energy Harvester". Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc984261/.
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This work presents an investigation of a piezoelectric sensor based energy harvesting system, which collects energy from the surrounding environment. Increasing costs and scarcity of fossil fuels is a great concern today for supplying power to electronic devices. Furthermore, generating electricity by ordinary methods is a complicated process. Disposal of chemical batteries and cables is polluting the nature every day. Due to these reasons, research on energy harvesting from renewable resources has become mandatory in order to achieve improved methods and strategies of generating and storing electricity. Many low power devices being used in everyday life can be powered by harvesting energy from natural energy resources. Power overhead and power energy efficiency is of prime concern in electronic circuits. In this work, an energy harvester is modeled and simulated in Simscape™ for the functional analysis and comparison of achieved outcomes with previous work. Results demonstrate that the harvester produces power in the 0 μW to 100 μW range, which is an adequate amount to provide supply to low power devices. Power efficiency calculations also demonstrate that the implemented harvester is capable of generating and storing power for low power pervasive applications.
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Luo, Hongyu Shih Wei-Heng Shih Wan Y. "Colloidal processing of PMN-PT thick films for piezoelectric sensor applications /". Philadelphia, Pa. : Drexel University, 2005. http://dspace.library.drexel.edu/handle/1860/500.
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Dong, Biqin. "Cement-based piezoelectric ceramic composites for sensor applications in civil engineering /". View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202005%20DONG.
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Subbaramaiah, Rashmi. "Design of Vibration-Sourced Piezoelectric Harvester for Battery-Powered Sensor Networks". Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10690961.
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Energy harvesting is an important aspect in the field of energy and power systems. Utilizing road vibrations as the source to harvest energy has gained demand previously and advanced study on implementing distinctive designs for vibration sourced harvesters are currently in progress. A vibration sourced piezoelectric energy harvester design with road vibrations as the input source is proposed in this thesis and the outputs to validate the harvester design are simulated from the software COMSOL Multiphysics. The design comprises of two PZT-5J mass-spring oriented cantilever bimorphs to capture the road vibrations and three silicone rubbers to increase the stress applied on the bimorphs. A productive piezoelectric energy harvester is implemented to work in low and high vibration conditions and maximum power output of 57mW is obtained by the simulation. The results obtained prove piezoelectric energy harvesting design as an efficient design that can be used to serve sensors and wireless applications.
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Oliveira, Éder Luiz. "Application of piezoelectric materials as sensor and actuator for aeroelastic investigation". Instituto Tecnológico de Aeronáutica, 2014. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=3038.
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This dissertation aims to apply piezoelectric materials as actuator and sensor to perform aeroelastic analysis. Two semi-span wing models based on flat plates with different characteristics were tested using PZT (Lead Zirconate Titanate) as actuator, PVDF (Polyvinylidene Fluoride) as sensor and the results were compared with vibrometer laser results. An aluminum model with a ballast on the wing tip, whose its location can be modified was tested in experimental modal analysis. Using the aluninum model, an investigation about aeroelastic behaviour was conducted in wind tunnel and the V-g/V-f diagram determined. This diagram shows the aeroelastic evolution of the natural frequencies and damping as function of speed (or dynamic pressure). In this aeroelastic analysis, the ability of the PVDF in determining the V-g/V-f diagram was evaluated. A numerical model of composite flat plate was generated considering the piezoelectric instrumentations. The second specimen tested corresponds to composite wing models that are based on laminate composite flat plate. Five models with different fiber orientations were tested in (pure) experimental modal analyses and wind tunnel, hence, the capability of excitation of PZT was verified. Good results were obtained regarding the estimation of natural frequency and damping factor using a single PVDF element. The application of PZT as actuator in the wind tunnel test showed improvement on the data acquisition in terms of noise. However, were observed some characteristics that require careful. As support to experimental tests, several studies were performed.
15
Sun, Fanping. "Piezoelectric active sensor and electric impedance approach for structural dynamic measurement". Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-08292008-063023/.
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Lund, Anja. "Melt spun piezoelectric textile fibres : an experimental study". Doctoral thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3682.
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The manufacturing and characterisation of piezoelectric textile fibres are described in this thesis. A piezoelectric material is one that generates an electric voltage when deformed, a property which exists in a number of materials. The polymer with the strongest known piezoelectric effect today is poly(vinylidene fluoride) (PVDF), however it must be processed under certain conditions to become piezoelectric. This study shows that piezoelectric bicomponent PVDF-based fibres can be produced by melt spinning, which is a common and relatively simple fibre spinning method. The melt spinning process must include cold drawing, as this introduces a polar crystalline structure in the polymer. The fibres must also be electroded, which is done by producing bicomponent fibres with a core-and-sheath structure. The core is electrically conductive and constitutes an inner electrode consisting of a carbon black/polymer compound, whereas the sheath is PVDF and constitutes the piezoelectric component. Being sensitive to both deformation and temperature changes, these fibres are anticipated to be useful in a number of sensor applications. The flexibility and small size of the fibres makes it possible to include them as miniature-sensors in structures or garment without affecting the shape or comfort.
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Pakdel, Zahra. "Characterization, Modeling of Piezoelectric Pressure Transducer for Facilitation of Field Calibration". Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/76791.
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Currently in the marketplace, one of the important goals is to improve quality, and reliability. There is great interest in the engineering community to develop a field calibration technique concerning piezoelectric pressure sensor to reduce cost and improve reliability.
This paper summarizes the algorithm used to characterize and develop a model for a piezoelectric pressure transducer. The basic concept of the method is to excite the sensor using an electric force to capture the signature characteristic of the pressure transducer.
This document presents the frequency curve fitted model based on the high frequency excitation of the piezoelectric pressure transducer. It also presents the time domain model of the sensor. The time domain response of the frequency curve fitted model obtained in parallel with the frequency response of the time domain model and the comparison results are discussed. Moreover, the relation between model parameters and sensitivity extensively is investigated.
In order to detect damage and monitor the condition of the sensor on line the resonance frequency comparison method is presented. The relationship between sensitivity and the resonance frequency characteristic of the sensor extensively is investigated. The method of resonance monitoring greatly reduces the cost of hardware.
This work concludes with a software implementation of the signature comparison of the sensor based on a study of the experimental data. The software would be implemented in the control system.Master of Science
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Krsmanovic, Dalibor. "High temperature ultrasonic gas flow sensor based on lead free piezoelectric material". Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/245065.
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The review of current technologies for measurement of gas velocity in stack flow applications is undertaken and it is shown that the ultrasonic time-of-flight method is the most suitable and offers a number of advantages over alternatives. Weakness of current piezoelectric based transducers are identified as the inability to operate at temperatures above 400 °C due to limitation of piezoelectric materials used, and a case for development of an alternative high temperature material is put forward. A novel and highly enhanced, lead free piezoelectric material, suitable for continuous operation at temperatures above 400 °C has been engineered for ultrasonic gas velocity sensor applications. Structural modification of pure bismuth titanate (Bi4Ti3O12) or BIT compound, through multi-doping at the Ti-site, has been found to enhance piezoelectric properties accompanied with a mild reduction in Curie temperature, Tc. Initially, compounds doped with tungsten and chromium were found to increase the piezoelectric coefficient (d33) from around 5 pC N¯¹ in pure bismuth titanate, to above 20 pC N¯¹ in doped compounds. This increase is attributed to lower conductivity and improved poling conditions. Further increases in d33 (up to 35 pC N¯¹) were then realised through controlled grain growth and reduction in conductivity for niobium, tantalum and antimony doped compounds. The Curie temperature of the material with best properties is found to be 667 °C, which is a slight reduction from 675 °C for pure bismuth titanate ceramic. The enhancements in modified bismuth titanate achieved in present work allow the material to be considered as suitable for high temperature ultrasonic transducer applications. Integration of bismuth titanate material into a working high temperature transducer is then considered and the investigation of suitable, high temperature bonding method is undertaken. It is shown that reactivity of bismuth titanate with the titanium based fillers makes brazing unsuitable as a bonding method between piezo-ceramics and stainless steel. A novel assembly method, using liquid gallium as an electrically conductive bond, and a mechanical restraint for the piezo actuator is then presented as an alternative with the potential to reduce the negative effects of differences in thermal expansion coefficients between constituents of the transducer assembly.
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Xia, YuXin M. B. A. Sloan School of Management. "Self-powered wireless sensor system using MEMS piezoelectric micro power generator (PMPG)". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37091.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (leaves 99-102).
A thin-film lead zirconate titanate, Pb(Zr,Ti)03, MEMS Piezoelectric Micro Power Generator (PMPG) has been integrated with a commercial wireless sensor node (Telos), to demonstrate a self-powered RF temperature sensor module. PMPG and a power management module are designed to satisfy sensor node's power requirement. An electro-mechanical model of PMPG has been developed to maximize power output. The 2nd generation PMPG is designed to provide 0.173 mW power at 3 V DC with a natural frequency of 155.5 Hz. The power management module is developed to provide AC-DC rectification, energy storage, and active switching between PMPG and application circuit. To minimize power consumption, sensor data is taken at a discontinuous interval. A test bed is developed, which mimics that of a liquid gas pipeline used in the Alaska, where the self-powered sensor be used to monitor pipeline temperature.
by YuXin Xia.
M.Eng.
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Tran, Prenn Xuan. "A Study of Measuring Intracranial Pressure Using a Non-Invasive Piezoelectric Sensor". Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/52573.
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The brain, like many parts of the human body, can experience swelling, also known as cerebral edema. Cerebral edema may occur because of an injury, health related issues, tumors, or even high altitudes[1]. When cerebral edema occurs, a rise in intracranial pressure (ICP) becomes prevalent and may cause a serious threat.
Without immediate treatment, increased intracranial pressure can prevent blood from flowing to the brain and depriving it of necessary oxygen it needs to function. A normal ICP is usually between 5-15 mmHg (666 Pa - 1333Pa). Any ICP observed to be above 20 mmHg (2666Pa) can be associated with brain ischemia and is usually treated[2, 3]. If prolonged, high intracranial pressures can be fatal.
Current methods of measuring increased ICP are invasive and may involve drilling into the skull. Extreme invasive measures are not always suitable for certain situations. This thesis presents a study of a non-invasive sensor using piezoelectric PVDF wire to measure the ICP. The PVDF wire sensor is wrapped around the outer portion of the human head to measure the integrated hoop strain. Using this hoop strain, the pressure is then calculated from a known coupling factor of strain to pressure outputted from finite element modeling simulations. The coupling factor is then incorporated into a final calibration factor to calibrate the piezoelectric PVDF wire sensor from charge (Picocoulomb) to pressure (Pascal). These calibration factors are proven to be primarily dependent on the circumference of the human skull.
Furthermore, part of this study analyzed the effectiveness and validity of the sensor due to asymmetries in the human skull. A comparison of analytical analysis results versus computational results using finite element modeling simulations show that the PVDF wire sensor neglects any asymmetries presented within the test subject. The results of this study show that this sensor will output correct ICP measurements of different subjects using appropriate calibration factors and is a viable option for measuring ICP non-invasively.Master of Science
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Ajitsaria, Jyoti K. Choe Song-Yul. "Modeling and analysis of PZT micropower generator". Auburn, Ala, 2008. http://hdl.handle.net/10415/1489.
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Miller, Ross James. "Artificial Skin Tactile Sensor For Prosthetic and Robotic Applications". DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/435.
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To solve the problem of limited tactile sensing in humanoid robotics as well as provide for future planned mechanical prostheses, an innovative tactile sensor system was created and embedded into two realistic-looking artificial skin gloves. These artificial skin tactile sensors used small piezoelectric ceramic disks to measure applied force at multiple points on each glove. The gloves were created using silicone rubber to simulate both the texture and look of human skin, while maintaining both flexibility and durability. The sensor outputs were buffered by high-impedance voltage-following operational amplifiers, and then read sequentially using a multiplexing scheme by a microcontroller. Sensor data were sent via USB to a computer, where a graphical user display was created to show the tactile information in real time. These prototypes successfully demonstrated the viability of small piezoelectric elements embedded in silicone rubber for use in creating flexible and elastic tactile sensors.
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Li, Menghui. "Fabrication of reliable, self-biased and nonlinear magnetoelectric composites and their applications". Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/50656.
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The magnetoelectric (ME) effect, i.e., the induction of magnetization by an applied electric field (E) or a polarization by an applied magnetic field (H), is of great interest to researchers due to its potential applications in magnetic sensors. Moreover, the ME effect in laminate composites is known to be much higher than in single phase and particulate composites due to combination of the magnetostrictive and piezoelectric effects in the individual layers. Given that the highest ME coefficient have been found in Metglas/piezo-fiber laminate composites, this study was designed to investigate and enhance the magnetoelectric (ME) effect in Metglas/piezo-fiber laminate composites, as well as develop their potential for magnetic sensor applications.
To initiate this investigation, a theoretical model was derived to analyze the thickness effect of the magnetostrictive, piezoelectric, epoxy and Kapton layers on the ME coefficient. As a result, the importance of the coupling effect by epoxy layers was revealed. I used spin-coating, vacuum bagging, hot pressing, and screen printing techniques to decrease the thickness of the epoxy layer in order to maintain homogeneity, and to obtain good repeatability of the 16 ME laminates fabricated at one time. This protocol resulted in a more efficient way to induce self-stress to Metglas/PZT laminates, which is essential for increasing the ME coefficient.
With an enhanced ME effect in the Metglas/piezo-fiber laminates, magnetic field sensitivity could then be increased. An ME sensor unit, which consisted of a Metglas/PMN-PT laminate and a low noise charge amplifier, had a magnetic field sensitivity of 10 pT/Hz0.5 in a well-shielded environment. Stacking four of these ME laminates could further increase the signal-to-noise (SNR) ratio. I studied the optimized distance between a pair of Metglas/PZT ME laminates. A stack of up to four ME sensors was constructed to decrease the equivalent magnetic noise. The magnetic field sensitivity was effectively enhanced compared to a single laminate. Finally, a number of four Metglas/PZT sensor units array was constructed to further increase the sensitivity.
ME laminate composites operated in passive mode have typically required an external magnetic bias field in order to maximize the value of the piezomagnetic coefficient, which has many drawbacks. I studied the ME effect in an Ni/Metglas/PZT laminate at zero bias field by utilizing the remnant magnetization between the Ni and Metglas layers. To further enhance this effect, annealed Metglas was bonded on the Metglas/PZT laminate since it is known that hard-soft ferromagnetic bilayers generate built-in magnetic field in these Metglas layers. As a result, giant αME values could be achieved at a zero bias field at low frequency range or at electromechanical resonance (EMR). The sensor unit consisting of self-biased ME laminate arrays is considerably smaller compared to a unit that uses magnet-biased ME laminates.
Introducing the converse ME effect and nonlinear ME effect in Metglas/piezo-fiber laminates affords a variety of potential applications. Therefore, I theoretically and experimentally studied converse ME effects in laminates with longitudinally magnetized and longitudinally poled, or (L-L) mode. The optimum structure for producing the maximum effect was obtained for Metglas/PZT laminates. Additionally, the optimum structure and materials for enhancing the nonlinear ME effect in Metglas/PZT laminates are reviewed herein. In particular, this study revealed that modulating the EMR in laminates with high-Q piezo-fibers could enhance the SNR. The stress effect on nonlinear ME effect is also discussed—namely that magnetic field sensitivities can be enhanced by this modulation-demodulation technique.Ph. D.
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Abbas, Syed Farhat. "Development of a low cost shock pressure sensor". Ohio : Ohio University, 1988. http://www.ohiolink.edu/etd/view.cgi?ohiou1182538469.
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Hahn, Dale. "Biofilm response to isopropanol in an aqueous environment measured by a piezoelectric sensor". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0007/MQ43168.pdf.
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VAHLBERG, ANNA. "Textile Sensor Using Piezoelectric Fibers for Measuring Dynamic Compression in a Bowel Stent". Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-17999.
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In this experimental study the in-lined poled piezoelectric poly(vinylidene fluoride)(PVDF) bicomponent fiber was investigated the suitability in applications within the area of textile sensors when used in a bowel stent. Today there are only piezoelectric films made of PVDF available. Compared to a film, a fiber increases the amounts of application abilities. In this study a plain weave, resembling a coordinate system was made of the piezoelectric PVDF fiber and tested on top of two different beds; one hard and one elastic made of foam. The structure was then developed into two structures; one integrated in the stents structure with a plain weave pattern and one secondary structure as a plain weave placed onto the stent. Two test methods were developed in order to resemble the bowel movements to test the two piezoelectric PVDF fiber based structures. A reliability test in a reometer was made of the fiber, giving high differences in mean values. An in vivo test was conducted in a pig where the stent was placed in the orifice of the stomach. Both structures shown response when both developed methods was used. Due to large irregularities within the piezoelectric PVDF fiber the evaluation between the two structures was not possible. The most favorable structure was the secondary structure due to the larger continuous process ability and application areas. It was also seen that the reliability of the piezoelectric PVDF fiber is low, giving a non-reliable sensor.Program: Textilteknik
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Falconi, Daniel Rodrigo. "Sensor piezelétrico baseado na tecnologia dos eletretos termo-formados: aprimoramentos dos processos de produção". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18152/tde-20042010-095926/.
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Este trabalho descreve dois novos aprimoramentos dos processos para a produção dos eletretos termo-formados, cuja tecnologia é prioritariamente voltada para sensores piezelétricos. Estes sensores constituem-se de dois filmes de Teflon FEP unidos, contendo entre suas interfaces microbolhas com as superfícies superior e inferior carregadas eletricamente com polaridades opostas, formando grandes dipolos. Esta estrutura permite a alteração dos momentos de dipolo quando solicitada mecânica e eletricamente - o que confere a estrutura uma excelente atividade piezelétrica, com coeficientes piezelétricos atingindo valores superiores a 300 pC/N. No estágio atual, o processo para produção desses sensores é artesanal e produz, geralmente, amostras com deformações em suas bolhas. Contudo, os novos aprimoramentos, aqui apresentados, suprem as deficiências aludidas e possibilitam um maior controle da distribuição, altura e diâmetro das bolhas de ar. Os aprimoramentos do processo foram denominados laminação a quente e adesivo a frio. Basicamente, estes dois processos consistem em quatro etapas: a moldagem do filme de uma das camadas do sensor; a colagem das duas camadas de filmes de sensor; a metalização das superfícies do sensor e o carregamento elétrico, sendo a colagem o ponto crucial e diferente nos dois processos. Ressalta-se que suas principais contribuições relativas aos processos existentes foram a moldagem prévia do filme de uma das camadas e esses novos processos de colagem. Assim, estes aprimoramentos têm permitido um melhor controle das dimensões das bolhas e facilitado sobremaneira sua implementação em escala industrial. Desta forma, vislumbra-se um aumento significativo de aplicações comerciais desses sensores, a exemplo dos sensores de presença, teclados finos, balanças dinâmicas e sensores de pressão. Também como contribuição deste trabalho, coloca-se a implementação do sistema de medidas do coeficiente piezelétrico.This work describes two improvements on the production of piezoelectric sensors, which are based on thermo-formed electrets technology. These sensors which were previously prepared by fusing and molding two Teflon FEP films into bubbles structures in a hot-press system, presented piezoelectric coefficients over 300 pC/N after properly electrical charging. However, this production system still presents many technical challenges, most of them concerning the bubble formation. With the improvements, called hot lamination and cold adhesive, a much better control of the distribution, height and diameter of the air bubbles could be obtained. These improvements process can be described into four main stages: the molding of one film; the sticking process of the two films; the metallization of their surfaces followed by electric charging. The sticking processes and the previous molding of the film are crucial and the great contribution of this work. With these contributions not only better sensor could be made but it also facilitated the industrial scale implementation of the sensors. Another expressive contribution of this work was the development of a system to measure the piezoelectric coefficient.
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RUNDQVIST, KARIN. "Piezoelectric behaviour of woven constructions based on poly(vinylidene fluoride) bicomponent fibres". Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-17386.
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During this project it was investigated how the newly developed piezoelectric PVDF bicomponent fibre behaved when integrated in different weave constructions. The possibility to integrate conductive yarns as outer electrode was studied in order to see if it was possible to create a fully textile piezoelectric sensors. The piezoelectric properties of the bicomponent fibre is given by the sheath material, which is a polymeric material known as poly(vinylidene fluoride) (PVDF). Today only piezoelectric film made by PVDF is commercially available, but with a flexible PVDF bicomponent fibre it improves the possibility to integrate piezoelectric material into a textile construction. In this study the PVDF bicomponent fibre was integrated in the warp direction into weave constructions, such as plain weave, twill and weft rib. All the woven bands included 60 PVDF bicomponent yarns, with 24 filaments in each bundle and the average width of the bands produced was 30 mm. Different conductive materials and fibres, acting as outer electrode, were coated or integrated together with the PVDF fibre and the behaviour of the PVDF fibres was analysed. All the woven samples went through corona poling with a voltage of 7 kV in 70 ⁰C for 3 min. The weave construction that gave highest piezoelectric output signal was twill with weft that has low tex. The twill construction gave a range amplitude of 1.5- 3.3 V when subjected to a dynamic strain of about 0.25% at 4 Hz. It was shown that different conductive materials influenced the PVDF fibre in different ways, due to the resistance of the material. It was also shown that it was possible to integrate piezoelectric bicomponent fibre into a textile construction and that a fully textile piezoelectric sensor could be produced by using conductive yarns as outer electrode.Program: Masterutbildning i textilteknik,
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Saini, Navtej Singh. "UHF RFID Sensor Tag for Tire Monitoring". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480629684843769.
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Zhang, Chen. "Piezoelectric-Based Gas Sensors for Harsh Environment Gas Component Monitoring". Thesis, University of North Texas, 2019. https://digital.library.unt.edu/ark:/67531/metadc1538769/.
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In this study, gas sensing systems that are based on piezoelectric smart material and structures are proposed, designed, developed, and tested, which are mainly aimed to address the temperature dependent CO2 gas sensing in a real environment. The state-of-the-art of gas sensing technologies are firstly reviewed and discussed for their pros and cons. The adsorption mechanisms including physisorption and chemisorption are subsequently investigated to characterize and provide solutions to various gas sensors. Particularly, a QCM based gas sensor and a C-axis inclined zigzag ZnO FBAR gas sensor are designed and analyzed for their performance on room temperature CO2 gas sensing, which fall into the scope of physisorption. In contrast, a Langasite (LGS) surface acoustic wave (SAW) based acetone vapor sensor is designed, developed, and tested, which is based on the chemisorption analysis of the LGS substrate. Moreover, solid state gas sensors are characterized and analyzed for chemisorption-based sensitive sensing thin film development, which can be further applied to piezoelectric-based gas sensors (i.e. Ca doped ZnO LGS SAW gas sensors) for performance enhanced CO2 gas sensing. Additionally, an innovative MEMS micro cantilever beam is proposed based on the LGS nanofabrication, which can be potentially applied for gas sensing, when combined with ZnO nanorods deposition. Principal component analysis (PCA) is employed for cross-sensitivity analysis, by which high temperature gas sensing in a real environment can be achieved. The proposed gas sensing systems are designated to work in a high temperature environment by taking advantage of the high temperature stability of the piezoelectric substrates.
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Lin, Xiao. "Structural Health Monitoring using Geophysical Migration Technique with Built-in Piezoelectric Sensor/Actuator Array". NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010324-152020.
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Lamb waves based ultrasonic testing has been studiedfor many years. However, conventional methods of generatingand collecting of Lamb waves usually require bulky instruments and manual interference, thus can not be applieddirectly for in-situ or in-service monitoring of thestructural health. Especially, the method of interpretingthe Lamb waves in an active structural health monitoring(SHM) system with built-in piezoelectric sensors/actuatorsis not available yet. The objective of this study was to propose and validate, through numerical simulation and experimental studies, the feasibility of adopting the geophysical migration method to interpret the ultrasonic Lamb wave signals for the purpose of realizing quantitative damage identification. A homogeneous isotropic plate with a surface-mountedlinear piezoelectric ceramic (PZT) disk array is studied as an example. The piezoelectric disks act as actuators to excite Lamb waves and also as sensors to receive the waves reflected from the structural anomaly in the plate. The migration technique, which is an advanced technique in geophysics to reverse the reflection wave field and to image the Earth interior, is then used to back-propagate the recorded wave signals and to visually image the damage in the plate. Mindlin plate theory is adopted to model the propagating waves, and a two-dimensional 2-6 order explicit finite difference algorithm is used to synthesize the reflection waves and to implement the migration process. The stability and accuracy criteria of the finite differencealgorithm when used in plate problems is discussed. An analytical solution is derived for the transient Lamb waves of an infinite plate subject to a point loading. This solution is used to verify the accuracy of the finite difference calculation. Both poststack and prestack migration are studied to propagate the reflection energy back to the damages. For the poststack migration, a one-way version of flexural wave equation is derived and the data pre-processing procedures before migration, such as muting direct arrival, deconvolution and stacking, are discussed. For prestack migration, an excitation-time imaging condition specifically for the migration of waves in a plate is introduced based on ray-tracing concepts and the asymptotic properties of flexural wave velocities and the migration is proceeded through the full-way wave equation. The results of numerical simulation show that the migration method possesses the capability of identifying multiple discrete damages without a priori assumption on the distribution pattern of the damages. Thus not only the existence but also the shape and the dimensions of the damages can be visually identified. An experimental apparatus is then set up to validate the conclusions drawn from the synthetic data. For calibration of the system, an analytical model of the waves in a plate incorporated with PZT sensors/actuators is developed. The agreement between the model calculated data and the measured data in the experiment shows that A0 mode Lamb waves are accurately generated and collected. Finally, the migration results from the reflection waves of an artificial damage in an arc shape recorded in the experiment are presented. It is shown that the existence of the damage could be correctly imaged through the migration process as it was shown in the numerical simulation.
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Morales, Connor. "Piezoelectric Sonar Sensor Design and Use for Bathymetric Map Creation by Unmanned Aerial Vehicles". Thesis, University of the Pacific, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10602509.
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A genetic algorithm from literature is adapted to design piezoelectric sonar sensors using results from physics simulations to optimize for a uniform voltage response over a wide range of frequencies. The adapted genetic algorithm produces valid sensor designs, and algorithm improvements are proposed. The best case general methods for bathymetric mapping with a sonar sensor is determined by sweeping various point selection algorithms, interpolation algorithms, and algorithm parameters. A set of methods are proposed based on how many sample points are used and what error metric is preferred. Additional algorithms are suggested for future improvements.
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Lin, Chih-Ting, i 林致廷. "Redeployment of Piezoelectric Point Sensor by Using Distributed Piezoelectric Sensor Technology". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/01602834485433449821.
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碩士國立臺灣大學
應用力學研究所
86
Point sensors and distributed sensors have both been developed for several decades. The advantages of point sensors as compared to distributed sensors are quite different and both have their own limitations. Based on the linear piezoelectric sensor theory, piezoelectric point sensors and piezoelectric distributed sensors have been developed. A sensor model has been investigated and established. The experimental result to verify the unique characteristics of the piezoelectric sensor as well as the distributed point sensor. Based on the integrated distributed and point sensor, an innovative distributed accelerometer has been developed. The design principle as well as application implications of this newly developed accelerometer are detailed.
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TSENG, WEI-MING, i 曾韋銘. "Wearable piezoelectric telescopic intelligent sensor". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/mny259.
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碩士國立中正大學
機械工程系研究所
105
This research presents a multifunctional and stretchable smart patch. This patch contains the piezoelectric (PZT film) node array for sensing acoustic emission (AE) wave and thermally activated PNIPAM nodes for delivering drug. The PZT sensing node array is realized on a thin flexible titanium sheet with serpentine network electrically connected. This design has two novelties: (1) the serpentine network allows the node array to stretch in an arbitrary planar direction; (2) the normal force of AE detection head coupling to the sensing object can be enhanced while the patch stretched. The thermal actuator and temperature controlled drug release module both fabricated with PNIPAM is also reported for the first time.
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Cheng, Tzong-Jih, i 鄭宗記. "Piezoelectric Quartz Crystal Sensor for". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/62893536958367343626.
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博士國立成功大學
醫學工程研究所
89
This study utilizes piezoelectric quartz crystal (PQC) sensors as an analytical tool for biomedical applications. Application fields contain blood coagulation tests, developing an affinity biosensor and interfacial study by integrating an electrochemically analytical technology. This investigation aims to extend the applications of PQC sensors to clinical tests, and to developing novel biosensors and basic interfacial sensor research. Topics covered herein include blood coagulation studies and the development of an affinity biosensor. The contents of each chapter are listed below: Part 1: Determination of plasma prothrombin time using a PQC sensor. The extent to which a PQC sensor was influenced by liquid viscosity was studied herein, as was the sensor’s application to estimating blood coagulation time and its application to estimating blood coagulation time. The relationship between the frequency shift (Df) of PQC and the physical properties of the contacting liquid was also examined. Glycerol solutions with various weight percentages were adjusted to various viscosities. The Df is inversely linearly proportionate to (rlhl)1/2 in general blood conditions (0.14 s-1/2g-1cm2.). The sensing function to liquid density and viscosity was utilized to monitor blood coagulation and determine coagulation time in real time. PQC sensors with adequate sensitivity to slight viscosity changes are employed to monitor blood coagulation. The case of an anticoagulated plasma specimen, prothrombin time (PT) was determined by the PQC sensor based on the introduction of tissue thromboplastin (TF) and calcium ion. The PQC data reveals that the best linear relation ship in a double-logarithmic plot of PT versus TF concentration in the range of 5.466 ~ 22.311 units/ml appeared at 90% of the total frequency shift. The PQC result was compared with a commercial optical coagulometry and showed a strong linear correlation (ca. 0.98). The PQC sensor can potentially be used in basic hematology research owing to its real time monitoring capability, which overcomes the drawbacks of the end-point method used in traditional coagulometers. Furthermore, the PQC sensor has an advantage in satisfying future demand for bedside and home-care products in that only a 20 ml sample is required for testing. Part 2: Determining heparin levels in blood with activated partial thromboplastin time using a PQC sensor. A PQC sensor was used to determine both whole blood activated partial thromboplastin time (WBaPTT) and plasma activated partial thromboplastin time (PLaPTT) induced by anticoagulant heparin. The PQC sensor results revealed a linear relationship between WBaPTT (or PLaPTT) and heparin levels in clinically relevant concentrations (0~0.4 unit/ml). The mean of individual R2 (= 0.9491) for a regressive curve between WBaPTT and heparin concentrations was shown sufficiently clearly. The PQC method can be employed to assess the influence of heparin through determining WBaPTT, since its sensitivity (P< 0.01) is comparable to that of aPTT by optical coagulometry (OCaPTT). Furthermore, the results of WBaPTT with various heparin concentrations (n = 9) were found to be closely correlated with those of OCaPTT (correlation coefficient = 0.9441). Linear calibration plots were extended into 3 units/ml of heparin in PLaPTT and WBaPTT. Measured results indicate that the prototype coagulometer based on PQC sensor has a closer linear relationship than the optical coagulometer in high-dose ranges of heparin. It has been suggested that the PQC method is more convenient, which may be useful in clinical situations for rapid monitoring heparin therapy using a small volume (20 ml) of whole blood specimens. The PQC method has three advantages in heparin assay: rapid analysis (from 80 to 600 sec), wide detection range (0~3.0 units/ml) and convenient sample preparation (whole blood is available). Part 3: Studies of whole blood coagulation using PQC sensors. This section builds on the previous two chapters regarding applications of PQC sensors to hematological studies, and particularly in assessing the practicability of applying PQC sensors to whole blood coagulation tests. Long-term (3000 sec) and real time viscosity monitoring was conducted during whole blood clotting. Viscosity is insignificant in PQC responses between whole blood and plasma. A step-like response curve is also obtained from analyzing whole blood coagulation within 1000 seconds, an acceptable time period, in clinical trials. A comparison of responses between whole blood and plasma coagulation does not reveal interferences on the surface of the PQC sensor by cells and proteins in blood. Additionally, it is practical to apply the PQC sensor to studies of whole blood coagulation via research on whole blood recalcification time. A PQC sensor was used to determine whole blood clotting time (CT) to quantitatively analyze heparin concentrations in blood. An obvious linear relationship existed between whole blood CT and heparin concentration from 0 to 0.1 units/ml, but the examination took over 1000 seconds. Consequently, while the results are analytically useful, the approach not be practical for application in clinics. Whole blood activated partial thromboplastin time (aPTT) was determined using a PQC sensor to investigate high concentrations of heparin in-vitro and ex-vivo. Ten thousand units of heparin were injected into each subject undergoing heparin treatment following a cardio catheter. Plasma aPTT could not be determined in over half of the blood sample using a commercially optical coagulometer. PQC sensors conducted all of the tests and the test results reveal an appropriate linear relationship, indicating the effectiveness of PQC in discriminating between anticoagulation and a normal condition. The “receiver operating characteristic” plot was used to comparatively assess sensitivity and specificity between different coagulation analyzers. The analytical results revealed that PQC performs better in distinguishing heparin anticoagulation than an optical coagulometer. Part 4: Development of a heparin sensor based on PQC. This investigation attempted to develop a heparin sensor for clinical use, possessing directive assessment, easy operability and a wide calibration range. Absolute concentrations of heparin in phosphate buffer solution (PBS, pH 7.4) were determined using PQC as an affinity biosensor, and electrochemical impedance spectroscopy (EIS) was used to investigate immobilization of protamine and heparin assay. Constructing a heparin sensor requires using protamine as a specifically recognized elements and using simple physical adsorption as an immobilization method to develop a heparin sensitive surface on a PQC gold electrode. The effectiveness of physical adsorption in immobilizing protamine was confirmed by examining the preparation condition, including incubation time and protamine concentration. The reduction in oscillating frequency of PQC (ca. -100 Hz) was maximized when applying 20 mg/ml protamine in PBS with a 20 minute incubation period. Heparin adsorption onto protamine-modified electrode in PBS revealed an exponential-like binding curve, and a long time was required to reach the steady state in the PQC frequency response. Furthermore, judging from the initial slope (df/dt) and frequency change (Df) of PQC two linear calibration curves were obtained after a binding interval (600 seconds) for heparin concentrations from 0 to 3.0 and 7.0 units/ml, respectively. Ten thousand ppm of bovine serum albumin (BSA) was used as mimic plasma to assess the interference of proteins in blood with a protamine-modified sensory surface. Interference causing a —50 Hz frequency shift will influence the sensing function of the heparin sensor, but might not be lethal. The EIS system was corporately employed to investigate preparation procedures and the sensing function of heparin sensors. In EIS analysis, calibration curves with a linear concentration range of 0~3.0 units/ml were also obtained for heparin in PBS when ferrocyanide was used as an electroactive marker. The EIS method will be conducive to designing micro sensing arrays that allow the development of inexpensive biosensors.
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Li, Chia-Hsien, i 李佳賢. "Development of flexible piezoelectric vibration sensor". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/51465862951700893573.
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碩士國立中興大學
機械工程學系所
100
In this study, a single-mode piezoelectric sensor for the detection of low-frequency vibration mechanical failure is developed. To have the single-mode sensor to be operated at low frequency, we deposited the PZT-silica composite films on a PI-copper flexible substrate at 150C by sol-gel technology. The advantage of using low-frequency single-mode sensor for the detection of mechanical failure is that no extra signal process system is required and vibration is able to be estimated by the output voltage directly in order to enhance the practicability and reduce the system cost. Experimental result showed that developed sensors operated at 76Hz. When the frequency is shifted by 5HZ, the sensitivity plummets by 50%. Due to the significant change, we can tell whether the vibration frequency of low-frequency machineries is shifted. As for the output, the sensitivity of sensors is large than 60mV/g. The sensors also were able to be used at large deflection test. After repetitions of testing, the change of sensitivity was less than 10%. Thus, when knocking occurs, our sensor has better endurance. The sensor output was able to detect vibration at specific frequency by scaling the signal and the signal process system could be simplified instead of using the spectrum technique. Keyword: Single-mode, flexible, low-frequency, piezoelectric sensor
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Bhat, Sudhakar. "Piezoelectric sensor for foot pressure measurement". 1989. http://catalog.hathitrust.org/api/volumes/oclc/22288872.html.
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Thesis (M.S.)--University of Wisconsin--Madison, 1989.Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 11-12).
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Garg, Atul. "Development Of Piezoelectric Thin Film Based Acoustic Sensor". Thesis, 2004. https://etd.iisc.ac.in/handle/2005/1207.
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Garg, Atul. "Development Of Piezoelectric Thin Film Based Acoustic Sensor". Thesis, 2004. http://etd.iisc.ernet.in/handle/2005/1207.
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Shie, Dung-ting, i 謝東廷. "Development of PZT Piezoelectric Sensor for Microbalance". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/05365324161518550268.
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碩士國立中央大學
電機工程研究所
97
In this research, microbalance devices were developed with piezoelectric material to measure biomass based on change of resonant frequency. The sensor structure consists of a square piezoelectric PZT thin film. The Pb1.2(Zr0.52Ti0.48)O3 (PZT) thin film was prepared on Pt/Ti/SiO2/Si surface by sol-gel coating method. We designed different sizes of working area (50 × 50 μm2, 100 × 100μm2, 250 × 250μm2, 400 × 400μm2) and verified piezoelectric properties of these PZT devices. The crystallization and microstructure of the PZT thin films were characterized by X-ray diffraction and scanning electron microscopy (SEM). In this result, the PZT thin film annealed at 700℃ for 50 min showed single-phase perovskite peaks. SEM micrograph revealed that the PZT film with thickness of about 600 nm has uniform microstructure without any cracks. In the electrical properties, the leakage current density rose as the piezoelectric working areas increased. The C-V property exhibited complete butterfly patterns, whose symmetry increased with increasing piezoelectric working areas. Besides, the tunability at 250 × 250μm2 working area was maximum, hence it has excellent piezoelectric characteristic. Further, we used potassium hydroxide (KOH) wet etching technique to reduce the backside thickness.This device has great potential for biomolecular detection.
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Chien, Bo-Ru, i 簡伯儒. "Blood Pressure Measurement Based On Piezoelectric Sensor". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8264w6.
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Tzeng, Yau-Shiuan, i 曾耀萱. "Piezoelectric Energy-harvesting Circuit for Wireless Sensor Modules". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/ks5fd7.
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碩士國立臺北科技大學
電能轉換與控制產業碩士專班
102
The main purpose of this study is to design a vibratory energy-harvesting system and integrate it with a ZigBee wireless sensor module. The concept behind the vibratory energy-harvesting system is collecting mechanical vibration energy and transforming it into electrical energy, which can be used as a supplying power for any electronic device. Most of the available vibratory energy harvesters (VEHs) capture only minute amounts of energy, as a result external power supplies or battery are required as auxiliary power sources. This, thereby, reduces the practicality and convenience of VEHs. Besides the additional power consumption by the sensing modules, the energy generated by the piezoelectric material is a minimal of about 5 ~ 9mW making it inadequate for driving any general common electronic device. Therefore the goal of this study is study the application on low-power wireless sensor modules. In this study, the Arduino LilyPad microcontroller is used in conjunction with a super capacitor to manage and control both the energy converted by the piezoelectric material and the data from the wireless sensor. However, this study uses four pieces of piezoelectric material for the 16.84 mW required by the microcontroller alone . The differences between input current of the piezoelectric material (on the μ level) and the maximum open-circuit voltage (multiples of 10V) makes it necessary to place energy storage, transmission circuit and a DC-DC converter at the front-end of the microcontroller for the control and protection of the input node. the microcontroller, control, energy saving (sleep mode) and data transmission process are achieved. As the system does not require any external power and batteries due to the adequate amount of power provided by the piezoelectric material, the objective of power self-sufficiency is achieved.
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Lo, Wen-Bin, i 羅文濱. "Flexible piezoelectric tactile sensor with structural electrodes array". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/31139458310626099986.
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碩士南台科技大學
機械工程系
95
The tactile sensor has flexible characteristic that it can be applied in the application with the human body physiological monitoring for example，pulse, heartbeat, blood pressure. However the piezoelectric-type tactile sensor sensitivity needs to be improved. Therefore we introduce the concept of structural electrode for enhancement of the sensitivity of piezoelectric tactile sensor and fabricated structure by MEMS process. A sandwich structure for flexible tactile sensor consists of top and bottom soft substrates made of Polystyrene, and in between of two soft substrates a piezoelectric thin film, PVDF, and patterned different area, are utilized as sensing material and microstructures, respectively and used shaker and force sensor. We design our experiment of tactile sensing system. The signal of a contact pressure to the tactile sensor are sensed and processed in the DAQ System. Finally the signals are integrated for taking the force profile. The processed signals of the output of the sensor are visualized on LabVIEW in personal computer in real time. A rudimentary tactile object image measurement procedure for applied loads has been devised to recognize the silhouette of a sharp edge, square, ,circle, the shape and force distribution of the contact object are obtained using two and three-dimensional image in real time.
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Shin, Min-Sheng, i 施敏升. "Modeling and Analysis of Piezoelectric Actuator and Sensor". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/51348357441529910644.
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碩士中原大學
機械工程研究所
90
This paper is an advance research about the actuator and sensor both driven by piezoelectric principle. For the actuator, this paper built series of theoretical model of piezoelectric bimorph actuator in both static and dynamic states and applied that theoretical model in the vibration system of parts feeder. We also simulation and analysis about the motion path of parts. The motion of parts has also been built theoretically to design the necessary vibration frequency and amplitudes. We hope to get the best transferring efficiency. The load capacity of the system is one of the important reasons to effect transferring efficiency. So the load capacity is one of the subjects in this paper. Finally, we test the real parts feeder. We can get a better transferring rate, safety, and precision when the parts feeder has higher operating frequency. For the sensor, this paper built series of theoretical model of vibration gyroscope. And research the relation about the angular speed with resonant frequency. The most important character of vibration gyroscope is its frequency of drive and detect should be quite close. That’s can get better sensitivity. However, you may not find it in many research reports. The vibration beam gyroscope which research by this paper, it’s frequency of input and output almost the same. So we can get the gyroscope has better sensitivity.
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Shrikanth, V. "A Non Resonant Piezoelectric Sensor for Mass, Force and Stiffness Measurements". Thesis, 2015. http://etd.iisc.ernet.in/2005/4000.
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The word piezo in greek means \to compress". Piezoelectric sensors work on the principle of direct piezoelectric effect, where a mechanical input generates a corresponding electric charge. The advantages of these sensors are wide fre-quency range of operation, high stiffness and small size. The main limitation of a piezoelectric sensor is that it cannot be used in measurements that are truly static. When a piezoelectric sensor is subjected to a static force, a fixed amount of charge is developed which would eventually decay at a rate dependent on the external impedance of the sensor circuitry. Operating sensors at resonance have been one of the methods to overcome the limitation of using piezoelectric sensors for static measurements. However, since both actuation and sensing are done by the same piezoelectric element, this results in a cross-talk of input and output signals.
The drawback of using single piezoelectric element for actuation and sensing is overcome in this work by using two identical elements|one for actuation and one for sensing. The operating frequency is about 10 % of the natural frequency of the sensor, thus enabling to operate the sensor in non resonant mode. Since the actuation and sensing mechanisms are separated, static measurement can be carried out. The output signal from the sensing element is monitored by a Lock-in amplifier which works on the principle of phase sensitive detection. The advantage of this sensor design is high sensitivity along with narrow band detection. It can be shown that the voltage output of the sensor Vout / a1 + m(b1 + b2F + b3K) + c1F + d1K, where m and K are the external mass and interaction stiffness, respectively, F is the force acting on it. By maintaining any two of these three quantities constant, the remaining one can be measured without any difficulty. The non resonant mode of operation makes it possible to explore the potential of this sensor in investigating mechanics of solid-liquid (viscous), solid-solid (inelastic) and solid-tissue(viscoelastic) interactions.
High sensitivity, wide range of measurement (1 g{1 g) and high resolutio(0.1 g) of the non resonant mass sensor makes it possible to use it in measure-ment of very small masses of the order 1 g. Typically, resonant sensors such as quartz crystal microbalance (QCM) are used for mass measurements at that range. However, since the performance of resonant sensors is controlled by damp-ing, a phenomenon known as `missing mass effect' arises. Operating a sensor in non resonant mode (stiffness controlled mode) is a way to overcome this problem, especially when the mass is viscous and/or viscoelastic in nature. Drosophila fly, egg and larvae are the viscoelastic masses that are measured using this non res-onant sensor. Evaporating sessile drops of water and Cetyl trimethylammonium bromide (CTAB) surfactant solution from nominally flat surfaces are monitored to characterize the sensor for viscous mass measurement. Evaporation rate per unit surface area remains more or less constant, during the initial stages of evap-oration. When the surfactant concentration is varied, evaporation rate per unit surface area is highest for solutions around critical miscelle concentration (CMC). A study is carried out to understand the effect of concentrations on spreading of ink over inkjet printing paper. It is found that the spreading is least around CMC, since spreading is dependent on the rate of evaporation.
The non resonant piezoelectric sensor which has high stiffness and quick re-sponse is also capable of measuring very small frictional forces. This sensor is configured to work as an inertial slider. Friction measurement at micro scales is important for designing microsystems such as stick-slip actuators. At such length scales, experiments have to performed at low loads and high excitation frequencies. The support stiffness of such systems should be high and the force of friction generated during slipping, when displacements are smaller than the contact radius, are of the order of few N. The displacement during slipping (S) is dependent on the amplitude of the input voltage to the actuation element. The frictional force measured during slipping by the sensor element indicates that the co-efficient of friction ( ) is independent of the sliding velocity.
The developed non resonant sensor in this work under small amplitude exci-tation, can measure force gradient (i.e. stiffness). The total force generated when a needle is inserted into a viscoelastic material is a sum of force due to stiffness of the material, friction and the cutting force at the tip. The force due to stiffness is dominant when the needle is bending the tissue before the puncture occurs. Use of the non resonant sensor in tandem with strain gauge force sensor enables distinguishing the three components of the total force. The slope of the force-displacement (F -d) curve during the initial stages of needle penetration into the viscoelastic material, before puncture, is indicative of the stiffness of the mate-rial. The peak force measured during penetration is higher for needles with larger diameters and lower insertion velocities. The viscoelastic response (relaxation) of the material remains independent of the insertion velocity, for a given thickness of the material and a constant needle diameter.
In summary, the sensor designed and developed in this work operates in stiffness controlled mode to eliminate the `missing mass effect' encountered dur-ing resonant mode of operation, has been clearly highlighted. Mass, force and stiffness measurements are possible over a wide range just by varying the ampli-tude of the input signal to the actuator element. The advantages such as high stiffness, small size and high response makes it advantageous to carry out in-situ micro scale studies in scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
46
Shrikanth, V. "A Non Resonant Piezoelectric Sensor for Mass, Force and Stiffness Measurements". Thesis, 2015. http://etd.iisc.ac.in/handle/2005/4029.
Pełny tekst źródłaStreszczenie:
The word piezo in greek means \to compress". Piezoelectric sensors work on the principle of direct piezoelectric effect, where a mechanical input generates a corresponding electric charge. The advantages of these sensors are wide fre-quency range of operation, high stiffness and small size. The main limitation of a piezoelectric sensor is that it cannot be used in measurements that are truly static. When a piezoelectric sensor is subjected to a static force, a fixed amount of charge is developed which would eventually decay at a rate dependent on the external impedance of the sensor circuitry. Operating sensors at resonance have been one of the methods to overcome the limitation of using piezoelectric sensors for static measurements. However, since both actuation and sensing are done by the same piezoelectric element, this results in a cross-talk of input and output signals.
The drawback of using single piezoelectric element for actuation and sensing is overcome in this work by using two identical elements|one for actuation and one for sensing. The operating frequency is about 10 % of the natural frequency of the sensor, thus enabling to operate the sensor in non resonant mode. Since the actuation and sensing mechanisms are separated, static measurement can be carried out. The output signal from the sensing element is monitored by a Lock-in amplifier which works on the principle of phase sensitive detection. The advantage of this sensor design is high sensitivity along with narrow band detection. It can be shown that the voltage output of the sensor Vout / a1 + m(b1 + b2F + b3K) + c1F + d1K, where m and K are the external mass and interaction stiffness, respectively, F is the force acting on it. By maintaining any two of these three quantities constant, the remaining one can be measured without any difficulty. The non resonant mode of operation makes it possible to explore the potential of this sensor in investigating mechanics of solid-liquid (viscous), solid-solid (inelastic) and solid-tissue(viscoelastic) interactions.
High sensitivity, wide range of measurement (1 g{1 g) and high resolutio(0.1 g) of the non resonant mass sensor makes it possible to use it in measure-ment of very small masses of the order 1 g. Typically, resonant sensors such as quartz crystal microbalance (QCM) are used for mass measurements at that range. However, since the performance of resonant sensors is controlled by damp-ing, a phenomenon known as `missing mass effect' arises. Operating a sensor in non resonant mode (stiffness controlled mode) is a way to overcome this problem, especially when the mass is viscous and/or viscoelastic in nature. Drosophila fly, egg and larvae are the viscoelastic masses that are measured using this non res-onant sensor. Evaporating sessile drops of water and Cetyl trimethylammonium bromide (CTAB) surfactant solution from nominally flat surfaces are monitored to characterize the sensor for viscous mass measurement. Evaporation rate per unit surface area remains more or less constant, during the initial stages of evap-oration. When the surfactant concentration is varied, evaporation rate per unit surface area is highest for solutions around critical miscelle concentration (CMC). A study is carried out to understand the effect of concentrations on spreading of ink over inkjet printing paper. It is found that the spreading is least around CMC, since spreading is dependent on the rate of evaporation.
The non resonant piezoelectric sensor which has high stiffness and quick re-sponse is also capable of measuring very small frictional forces. This sensor is configured to work as an inertial slider. Friction measurement at micro scales is important for designing microsystems such as stick-slip actuators. At such length scales, experiments have to performed at low loads and high excitation frequencies. The support stiffness of such systems should be high and the force of friction generated during slipping, when displacements are smaller than the contact radius, are of the order of few N. The displacement during slipping (S) is dependent on the amplitude of the input voltage to the actuation element. The frictional force measured during slipping by the sensor element indicates that the co-efficient of friction ( ) is independent of the sliding velocity.
The developed non resonant sensor in this work under small amplitude exci-tation, can measure force gradient (i.e. stiffness). The total force generated when a needle is inserted into a viscoelastic material is a sum of force due to stiffness of the material, friction and the cutting force at the tip. The force due to stiffness is dominant when the needle is bending the tissue before the puncture occurs. Use of the non resonant sensor in tandem with strain gauge force sensor enables distinguishing the three components of the total force. The slope of the force-displacement (F -d) curve during the initial stages of needle penetration into the viscoelastic material, before puncture, is indicative of the stiffness of the mate-rial. The peak force measured during penetration is higher for needles with larger diameters and lower insertion velocities. The viscoelastic response (relaxation) of the material remains independent of the insertion velocity, for a given thickness of the material and a constant needle diameter.
In summary, the sensor designed and developed in this work operates in stiffness controlled mode to eliminate the `missing mass effect' encountered dur-ing resonant mode of operation, has been clearly highlighted. Mass, force and stiffness measurements are possible over a wide range just by varying the ampli-tude of the input signal to the actuator element. The advantages such as high stiffness, small size and high response makes it advantageous to carry out in-situ micro scale studies in scanning electron microscopy (SEM) and transmission electron microscopy (TEM).
47
Guzmán, Sierra Dayana Lizethe. "Flexible piezoelectric bionanocomposites for biomedical sensors". Master's thesis, 2018. http://hdl.handle.net/10773/25894.
Pełny tekst źródłaStreszczenie:
In recent decades, there has been increasing interest in the development of new materials in order to achieve the "Internet of Things (IoT)" which provided for the connection of 20 to 30 billion devices to the Internet by 2020. The implementation of the "Internet of Things "requires the development of base technology, which includes transducers, actuators and sensors. Sensors are often used in biomedical applications that require flexibility, biocompatibility and sustainability. In this context, the motivation of this work was the preparation of a bionanocomposite for biocompatible piezoelectric sensors for biomedical applications. Thus, a polysaccharide that have the ability to form films (films), and particles of barium titanate which is ferroelectric and piezoelectric material at room temperature, having no lead in its composition.
The BaTiO3 particles were synthesized by hydrothermal method at moderate temperature (200 °C) and in the absence of organic solvents. Several reaction times were studied in order to select the ideal conditions for the particles preparation with the required properties to be incorporated in the chitosan-based films. The structural characterization by X-ray diffraction (XRD) and Raman spectroscopy allowed us to verify that the particles synthesized at 200 °C showed a well-defined tetragonal crystallographic structure after 24 hours of synthesis. The particles showed uniformed cubic morphology and average size of about 306 nm. In general, particle and crystallite sizes increase with reaction time. The films were obtained by the solvent evaporation method, after dispersing the particles in different proportions, in a solution of chitosan. Structural properties (XRD) and morphological (SEM); physical-chemical (mechanical, degree of humidity, solubility in water and contact angle, and Raman); and electrical (dielectric behavior, hysteresis curves and nanoscale piezoelectric response) of the films were characterized. The addition of particles improved the mechanical properties of the chitosan films, making them more resistant, elastic and ductile. These films have also been shown to be more resistant to water, which reveals that there is an interaction between the particles and the chitosan matrix. In relation to the electric behavior of the films, the increase of particles improves the permittivity of the samples five times in relation to the biopolymer material. It was verified a great difficulty of deposition of electrodes in the flexible films that can be justified on the basis of the characteristics of the samples and / or the inadequacy of the experimental conditions of deposition of the electrodes in the sample. It was not possible to measure the piezoelectric response at the macroscopic scale nor to polarize an area of the bionanocomposite sample. Thus, the piezoelectric response at the nanometric scale was studied by atomic microscopy of piezoelectric response. It was found that nanocomposite films with the highest concentration of nanoparticles clearly showed piezoelectric domains, but it is not possible to obtain an acceptable hysteresis curve and to polarize a small area of the nanocomposite. These observations, together with the analysis by surface potential microscopy of the control film (chitosan only) that indicates the presence of charges in the pure polymer, lead to the conclusion of an electret type behavior, being necessary a strategy to eliminate (or reduce) the matrix's contribution.
Despite the difficulties encountered due to degree of innovation of the work, the bionanocomposites developed based on chitosan and barium titanate are promising to be used in biomedical devices (drug release pads, etc.) since they have high mechanical resistance, elasticity, and ductility, as well as have higher resistance to conditions with high degree of humidity. In addition, they are biocompatible and partially biodegradable, being an excellent alternative to synthetic polymersNas últimas décadas, tem havido um interesse crescente no desenvolvimento de novos materiais com o intuito de alcançar a "Internet of Things (IoT)" que prevê a ligação de 20 a 30 bilhões de dispositivos à internet até 2020. A implementação da “Internet of Things” exige o desenvolvimento de tecnologia base, onde se incluem os dispositivos de captação de energia, atuadores e sensores. Os sensores são muitas vezes utilizados em aplicações biomédicas que exigem flexibilidade, biocompatibilidade e sustentabilidade. Neste contexto, a motivação deste trabalho foi a preparação de um bionanocompósito para sensores piezoelétricos biocompatíveis para aplicações biomédicas. Assim, escolheu-se como matriz um polissacarídeo que tem a capacidade de formar películas (filmes) facilmente, e partículas de titanado de bário que é um material ferroeléctrico e piezoeléctrico à temperatura ambiente, não possuindo chumbo na sua composição. As partículas de BaTiO3 foram sintetizadas por método hidrotermal a temperatura moderada (200 °C) e na ausência de solventes orgânicos. Foram estudadas vários tempos de reação de forma a selecionar as condições ideais para a preparação das partículas com as propriedades adequadas para a incorporação nos filmes à base de quitosana. A caracterização estrutural por difração de raios-X (DRX) e espectroscopia de Raman permitiu verificar que as partículas sintetizadas a 200 °C apresentavam, ao fim de 24 horas de síntese, a estrutura cristalográfica tetragonal bem definida. As partículas mostraram morfologia cúbica uniforme e tamanho médio de cerca de 306 nm. Em geral, os tamanhos das partículas e de cristalites aumentam com o tempo de reação. Os filmes foram obtidos pelo método de evaporação de solvente, após a dispersão das partículas, em diferentes proporções, numa solução de quitosana. As propriedades estruturais (DRX) e morfológicas (SEM); físico-químicas (mecânicas, grau de humidade, solubilidade em água e ângulo de contacto e Raman); e elétricas (comportamento dieléctrico, curvas de histerese e resposta piezoelétrica à escala nanométrica) dos filmes foram caracterizadas. A adição de partículas melhorou as características mecânicas dos filmes de quitosana, tornando-os mais resistentes, elásticos e dúcteis. Estes filmes revelaram também serem mais resistentes à água, o que revela que existe uma interação entre as partículas e a matriz de quitosana. Em relação ao comportamento elétrico dos filmes, o aumento de partículas melhora a permitividade das amostras cinco vezes em relação ao material biopolimérico. Foi verificada uma grande dificuldade de deposição de elétrodos nos filmes flexíveis que se pode justificar com base nas características das amostras e/ou na inadequação das condições experimentais de deposição dos elétrodos na amostra. Como não foi possível medir a resposta piezoeléctrica à escala macroscópica, nem polarizar uma área da amostra de bionanocompósito, fez-se o estudo da resposta piezoelétrica à escala nanométrica por microscopia atómica de resposta piezoelétrica. Os filmes com a concentração mais elevada de nanopartículas mostraram claramente domínios piezoelétricos, não sendo, contudo, possível traçar uma curva de histerese aceitável nem polarizar uma pequena área do nanocompósito. Esta observação, juntamente com a análise por microscopia de potencial de superfície do filme controlo (só de quitosana) que indica a presença de cargas no polímero puro, leva à conclusão da existência de um comportamento do tipo electret pelo que será necessário encontrar uma estratégia para eliminar (ou reduzir) a contribuição da matriz. Apesar das dificuldades encontradas, os bionanocompóstos desenvolvidos, à base de quitosana e titanato de bário são promissores para serem usados em dispositivos biomédicos (por exemplo em compressas para libertação de fármacos, etc.) devido à sua elevada resistência mecânica, elasticidade e ductilidade, sendo adaptados a condições de elevado grau de humidade. Estes bionanocompósitos são ainda biocompatíveis e parcialmente biodegradáveis, tendo potencial para serem usados como alternativa aos polímeros sintéticos
Mestrado em Materiais e Dispositivos Biomédicos
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Gokhale, Nikhil Suresh. "Studies On The Development Of Piezoelectric Thin Flm Based Impact Sensor". Thesis, 2008. https://etd.iisc.ac.in/handle/2005/770.
Pełny tekst źródłaStreszczenie:
Sensors is one of the major areas of current research. Thin film micro/nano sensors are gaining attention worldwide, as there is necessity of miniaturization. There are varieties of sensors available by utilizing different materials in bulk and thin film form for measuring parameters like temperature, pressure, flow, humidity etc. Apart from these, there are various sensors available to measure impact force.
Impact sensor offers potential application possibilities in robotics, aerospace, structural & mechanical engineering and related areas. Many physical principles have been explored for the realization of impact sensor. The present thesis reports the efforts made in developing impact sensor using piezoelectric thin film. The necessary brief background information on impact sensors is presented in Chapter 1. This includes the description of available literature on impact sensors and their probable applications. In Chapter 2, a review of the various techniques such as thin film deposition techniques, film thickness measurement techniques, thin film characterization techniques, used in our work are explained in detail. Chapter 3 explains the direct and indirect methods of characterization used for confirming the piezoelectric property of zinc oxide thin films. The detailed experimental work carried out in realizing the impact sensor using piezoelectric thin films is presented in chapter 4. This includes design of the sensor, calibration setup used & the procedure followed and results obtained.
Finally, we present the summary of the work carried out in the thesis, conclusions arrived at and the scope for carrying out further work in the direction of making the sensor more efficient.
49
Gokhale, Nikhil Suresh. "Studies On The Development Of Piezoelectric Thin Flm Based Impact Sensor". Thesis, 2008. http://hdl.handle.net/2005/770.
Pełny tekst źródłaStreszczenie:
Sensors is one of the major areas of current research. Thin film micro/nano sensors are gaining attention worldwide, as there is necessity of miniaturization. There are varieties of sensors available by utilizing different materials in bulk and thin film form for measuring parameters like temperature, pressure, flow, humidity etc. Apart from these, there are various sensors available to measure impact force.
Impact sensor offers potential application possibilities in robotics, aerospace, structural & mechanical engineering and related areas. Many physical principles have been explored for the realization of impact sensor. The present thesis reports the efforts made in developing impact sensor using piezoelectric thin film. The necessary brief background information on impact sensors is presented in Chapter 1. This includes the description of available literature on impact sensors and their probable applications. In Chapter 2, a review of the various techniques such as thin film deposition techniques, film thickness measurement techniques, thin film characterization techniques, used in our work are explained in detail. Chapter 3 explains the direct and indirect methods of characterization used for confirming the piezoelectric property of zinc oxide thin films. The detailed experimental work carried out in realizing the impact sensor using piezoelectric thin films is presented in chapter 4. This includes design of the sensor, calibration setup used & the procedure followed and results obtained.
Finally, we present the summary of the work carried out in the thesis, conclusions arrived at and the scope for carrying out further work in the direction of making the sensor more efficient.
50
Garcia, Juan Elias. "Piezoelectric transducer built-in self-test for logging while drilling instrument sensor evaluation at rig site". Thesis, 2014. http://hdl.handle.net/2152/26344.
Pełny tekst źródłaStreszczenie:
Logging While Drilling (LWD) instruments used in oil and gas exploration are subjected to extreme environmental conditions that make reliable operation a major challenge. The sensors directly exposed to this environment experience accelerated aging and may suffer physical damage leading to failure. The cost of drilling and rig operations is very high magnifying any failures or issues with LWD tools. The goal of this report is to present a built-in self-test for an instrument sensor that provides a means to evaluate sensor functionality. The sensor is a piezoelectric ultrasonic transducer. A brief review of the sensor physics will be given. I will review some methods for characterizing piezoelectric ceramic materials and transducers. The application of sensor test methods is applied in an ultrasound pulse-echo application. A brief review of the application circuit will be covered including state of the art in commercial ultrasound integrated circuit design. A prototype of the BIST method is evaluated using test transducers to verify the circuit provides indication of a transducers ability to function correctly. The prototype is achieved through the AD5933 demo board and MATLAB is used for data processing.text