Piezoelectric materials

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View of Simulation and comparison of electrical response of some piezoelectric materials used in the medical echography
							| Nova Scientia

View of Simulation and comparison of electrical response of some piezoelectric materials used in the medical echography | Nova Scientia

The acoustics is interpreted as the science that studies sound waves, vibrations and their interactions with the environment, in both macroscopic and microscopic systems. This paper presents the model of piezoelectric acoustic detector developed with the OrCAD-PSpice program, to determine the maximum voltage amplitude using piezoelectric materials such as Quartz, PZT-5H, PVDF and PSMNZT. Our objective is to determine which of these piezoelectric materials: natural, ceramics, polymers and composites ceramics generates the maximum voltage without adding a stage of signal conditioning. Thus we have a computational tool to predict the voltages applied that yield piezoelectric materials using the technique of transmission, in the absence of the equipment to perform these comparisons. The water is used as a propagation medium and we proposes different thicknesses for simulations. We show the simulation graphs, where the PSMNZT provided a maximum voltage 21.272V with a thickness of 10µm.
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23 Lee mas

Dissipative Finite Element Formulation Applied to Piezoelectric Materials With the Debye Memory

Dissipative Finite Element Formulation Applied to Piezoelectric Materials With the Debye Memory

Piezoelectric materials are widely used in mechatronic devices [?], [?], [?] due to their intrinsic ability to couple electric and mechanic energies. Consequently, these materials are commonly incorporated in sensors, actuators, ultrasonic transducers, smart structures, energy harvesters, medical de- vices, etc. There is then an increasing need for cutting-edge simulation tools to study and optimize current and future development of sophisticated industrial equipment.

8 Lee mas

Modeling Piezoelectric Harvesting Materials in Road Traffic Applications.

Modeling Piezoelectric Harvesting Materials in Road Traffic Applications.

In order to obtain an electrical model of piezoelectric materials used as generators in road traffic applications a test bench [19] was developed to genérate the electric signáis produced by the piezoelectric materials in real traffic environment. In several cases is necessary associate the response of the material to an electronic circuit, to analyze generated power [20], use discontinuous conduction converters [21, 23] or adaptive circuits for remote applications [22]. In our case, using the characterization data collected with our road traffic test bench, the input stage electrical model of the energy harvesting system is obtained. This paper reviews the type and optimal topological structure of semiconductor elements to achieve optimal efficiency inthat stage.
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6 Lee mas

Development and applications of sensors based on piezoelectric resonators

Development and applications of sensors based on piezoelectric resonators

One of the unique characteristics of the piezoelectric effect is that it is reversible, meaning that materials exhibiting the direct and inverse piezo- electric effect (see figure 1.1). When piezoelectric material is placed under mechanical stress (direct), a shifting of the positive and negative charge in the material takes place, which then results in an external electrical field. When reversed (inverse), an outer electrical field either stretches or compresses the piezoelectric material [Moh]. Only materials formed by fixed ions ordered in some manner can present this behaviour, as it is based on the existence of changing electric dipoles within the material structure [Nan]. There are many materials, both natural and man-made, that exhibit a range of piezoelectric effects. Some naturally piezoelectric occurring ma- terials include Berlinite (structurally identical to quartz), quartz, Rochelle salt, topaz, tourmaline, and bone. An example of man-made piezoelectric materials includes aluminium nitride (AlN) and lead zirconate titanate (PZT). These materials will be used in the resonators designed in this thesis since they present a greater sensitivity, a high dielectric constant, a high coupling and a high charge sensitivity compared to other materials.
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204 Lee mas

Ultra-Thin Piezoelectric Film Optimization

Ultra-Thin Piezoelectric Film Optimization

2.3 Material science In this project, among other things it is significant to know the structure and the properties of the materials that we are using (Pt, AlN, Al, SiO 2 ). A lot of properties of the materials depends on the crystal structure: the strength, the conductivity, the speed of light etc. Crystalline (“morphus”) material has it is atoms packed in periodic 3D arrays. On the other hand, the non- crystalline (“amorphous”) materials occurs in a complex structure and the atoms have no periodic packing. Solids are either crystalline or non-crystalline. Diverse piezoelectric materials are recognized (as quartz crystals, ceramics etc.). However only few are utilized for installation in MEMS devices as aluminum nitride, PZT, zinc oxide (ZnO), lithium niobate and lead magnesium niobate-lead titanate. Currently, AlN and PZT show the best fusion of coupling factor, mechanical quality and ease of deposition. [9] Even though PZT is most promising in terms of converting mechanical to electrical energy (best for MEMS power generation), we choice aluminum nitride because of its great potential especially in MEMS resonators in terms of acoustic properties, piezoelectric properties, high thermal conductivity and good compatibility with other electronic technologies. [10] [11] Since the largest piezoelectricity coefficients of aluminium nitride thin films are obtained with platinum substrate, the bottom electrode is from platinum. [12] The hexagonal crystal lattice of
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30 Lee mas

CMOS integration of AlN based piezoelectric microcantilevers

CMOS integration of AlN based piezoelectric microcantilevers

This drawback motivated our research group to develop a new set of CMOS compatible process steps designed to fabricate piezoelectric MEMS. Most piezoelectric materials manufacturing processes [28][29][30][31] limit the compatibility with CMOS technology due to their high deposition temperatures. These high temperatures can damage the performance and reliability of the CMOS electronics processed before, affecting relevant physical properties such as polycrystallinity, growth rate, mechanical properties, dopant activation, electrical resistivity, etc [32]. This effect is especially noticeable in the degradation of interconnects, rather than transistor device [33]. In this thesis work, CMOS integration is made possible through the usage of a piezoelectric material that can be deposited at low temperature. Aluminum nitride (AlN) provides the desired material properties for MEMS applications at significantly lower deposition temperatures compared to the majority of piezoelectric materials.
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135 Lee mas

Melt Spun Piezoelectric Textile Fibres - an Experimental Study

Melt Spun Piezoelectric Textile Fibres - an Experimental Study

Figure 30 Heartbeat signals generated from the piezoelectric fibres in a woven fabric strapped around the chest of a person holding his breath: raw signal (left) and filtered and amplified signal (right) [Paper V] Further, a demonstrator has been manufactured by embroidering a number of piezoelectric fibres on to a knitted glove, using couch stitch. The fibres thus constitute motion and temperature sensors in three positions (Fig. 31); the index finger joint, the back of the hand and on the tip of the thumb. Preliminary experiments 3 confirm that the sensors clearly register motion such as bending of the index finger and clenching of the fist, as well as the impact from tapping the thumb on a table surface (Fig. 32). The pyroelectric effect in the fibres was also confirmed by using the thumb sensor to register temperature variation; pressing the thumb to a bag of ice or to a cup of nearly boiling water produced the signals shown in Figure 33.
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68 Lee mas

Hojas de Seguridad de Materials

Hojas de Seguridad de Materials

Descargo de responsabilidad: Varn International, Inc. a Flint Group Company ha preparado estas "Hojas de seguridad de materials" (MSDS) cumpliendo con la norma 29 CFR 1910.1022, se sobreentiende que sus clientes pueden utilizar estos MSDS para cumplir con dicha seccion y se presume que los datos suministrados aqui son exactos en la fecha en que se suministran; Sin embargo, este MSDS no constituye una garantia al respecto.

6 Lee mas

Materials and methods

Materials and methods

(Myers et al. Some factors explaining this extraordinary diversity are: 1) a natural land bridge uniting three of the 25 recognized hotspots world-wide (Mesoamerica, Choco/Darién/West[r]

6 Lee mas

Construction materials savings

Construction materials savings

Construction Approaches and Options Avoiding to go into too much detail on the Construction Management approach, three aspects will be mentioned on this methodology: the Project Executio[r]

72 Lee mas

Materials i residus

Materials i residus

Infants des de 4 anys, joves i adults. Versió en línia de la guia Hàbitat, actualitzada i ampliada amb el suport de la Xarxa d'Escoles per la Sostenibilitat de Catalunya (XESC). Permet cercar activitats, compartir experiències i opinions. Les activitats centrades o relacionades amb els materials i residus són: La increïble història del Sr. Al’Um-Ini, Fes un bon paper, Objectes estranys al jardí, No m’emboliquis, Digue’m què llences i et diré qui ets, entre d’altres.

13 Lee mas

Hojas de Seguridad de Materials

Hojas de Seguridad de Materials

La inducción del vómito puede conducir a la aspiración del material a los pulmones, con el potencial de ocasionar neumonitis química que puede ser mortal.. MEDIDAS CONTRA INCENDIOS.[r]

6 Lee mas

Vector Control of Piezoelectric Transducers and Ultrasonic Actuators

Vector Control of Piezoelectric Transducers and Ultrasonic Actuators

III. EXPERIMENTAL RESULTS IN DIFFERENT EXAMPLES If the control of the piezoelectric transducers resembles that of the electromagnetic motors, its implementation is different because the pulsation of the supply voltage is much larger than the bandwidth of the vibration amplitude control. Moreover, the measured variables represent only the real parts of the corresponding complex vectors in the fixed frame (i.e the projections on the real axis on fig 2). It is therefore necessary to estimate in the vector in the rotating frame {d, q}. This implies to transport the real measurement in the rotating frame and reconstruct the missing imaginary parts of the various vectors. The practical implementation on a low cost DSP (STMicroelectronics STM32F4) is discussed below, as well as two experimental results on two applications, one requiring a resonance frequency tracking, the second operating at constant frequency.
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9 Lee mas

Study of a stator of a piezoelectric rotary ultrasonic motor

Study of a stator of a piezoelectric rotary ultrasonic motor

The reverse-piezoelectric effect occurs in the opposite way. Put a voltage across a piezoelectric crystal and you're subjecting the atoms inside it to "electrical pressure." They have to move to rebalance themselves—and that's what causes piezoelectric crystals to deform (slightly change shape) when you put a voltage across them. Some examples of these materials are quartz, berlinite, perovskite or engineered materials like lead zirconate titanate.

26 Lee mas

SURFACE AND INTERFACE WAVES IN PIEZOELECTRIC SANDWICH PLATES

SURFACE AND INTERFACE WAVES IN PIEZOELECTRIC SANDWICH PLATES

ε are the elastic stiffnesses, piezoelectric and dielectric permittivity constants. For these two particular assem- blies, the piezoelectric coefficients have opposite signs while all the other material coefficients are the same across the thickness of the structures, i.e.,

6 Lee mas

6. Materials de construcció.

6. Materials de construcció.

6. Materials de construcció. 8 Els materials ceràmics s’obtenen a partir d’argiles a les quals es poden afegir altres materials per modificar les seues propietats. Aquesta mescla es tritura, s’hi afig aigua, s’emmotla i es cou en un forn a altes temperatures.

12 Lee mas

fishing gear materials.

fishing gear materials.

A netting yarn experiences wearing due to environment. The term wear includes deterioration caused by mechanical factors such as rubbing against sea bottom surface (abrasion) and chemical factors (ultraviolet rays and microbial attack). Resistance to abrasion is different in different materials. A material with high strength, high elongation and high elasticity possess good abrasion resistance. Resistance to UV rays is dependent on the type of fibres, type of material and specification. It is measured by exposing the samples out doors to sunlight or in controlled conditions in the laboratory to source of UV rays. The mechanical properties of the sample on continuous exposure are recorded periodically and the material is considered unserviceable when 50% of the breaking load is lost.
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8 Lee mas

A Piezoelectric Minirheometer for Measuring the Viscosity of Polymer Microsamples

A Piezoelectric Minirheometer for Measuring the Viscosity of Polymer Microsamples

different polymers. But the voltage gain changes with the viscosity, as it is shown in the graph of Fig. 11. At lower and medium frequencies (where the piezoelectric transducers work in a nonresonant mode), it is observed that the higher the polymer viscosity, the higher the voltage gain. The higher viscosity implies higher dissipation, and hence, an increase in voltage gain seems counterintuitive. However, when a more viscous fluid is placed between the plates, energy is transferred more efficiently from the actuator to the sensor, and there is no contradiction in this result. When the frequency increases and the first resonance appears, the curves for different vis- cosities becomes very close, so the measuring frequency range is limited by the first resonance frequency: The piezoelectric minirheometer works only in a nonresonant mode. Fig. 11 also shows the overlap of all curves up to 10 5 Pa · s, limiting the
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10 Lee mas

Damage assessment in concrete structures using piezoelectric based sensors

Damage assessment in concrete structures using piezoelectric based sensors

Piezoelectric based PZT (Lead Zirconate Titanate) smart sensors offer significant potential for continuously monitoring the development and progression of internal damage in concrete structures. Changes in the resonant behavior in the measured electrical conductance obtained from electro-mechanical (EM) response of a PZT bonded to a concrete substrate is investigated for increasing levels of damage. Changes in the conductance resonant signature from EM conductance measurements are detected before visible signs of cracking. The root mean square deviation of the conductance signature at resonant peaks is shown to accurately reflect the level of damage in the substrate. The findings presented here provide a basis for developing a sensing methodology using PZT patches for continuous monitoring of concrete structures.
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11 Lee mas

Damage assessment in concrete structures using piezoelectric based sensors

Damage assessment in concrete structures using piezoelectric based sensors

Piezoelectric based PZT (Lead Zirconate Titanate) smart sensors offer significant potential for continuously monitoring the development and progression of internal damage in concrete structures. Changes in the resonant behavior in the measured electrical conductance obtained from electro-mechanical (EM) response of a PZT bonded to a concrete substrate is investigated for increasing levels of damage. Changes in the conductance resonant signature from EM conductance measurements are detected before visible signs of cracking. The root mean square deviation of the conductance signature at resonant peaks is shown to accurately reflect the level of damage in the substrate. The findings presented here provide a basis for developing a sensing methodology using PZT patches for continuous monitoring of concrete structures.
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11 Lee mas

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