Assessment of human bones encompassing physiological decay and damage using piezo sensors in non-bonded configuration

In the recent years, several biomedical applications of lead zirconate titanate piezo-electric ceramic patches based on the electro-mechanical impedance technique have been reported in the literature. However, practical application of the technique on live subjects is severely hampered due to the requirement of bonding the patch with bone or cartilage with an adhesive. In addition, live subjects have skin cover over the bone. This article proposes and evaluates the feasibility of employing lead zirconate titanate patches as biomedical sensors in non-bonded configuration for assessing the physiological conditions of bones. For this purpose, a special design is proposed where the lead zirconate titanate patch is first bonded on a thin aluminum strip, which is in turn clamped securely on the biomedical subject. The proposed configuration is investigated both in vitro and in vivo. The non-bonded piezo sensors are first investigated to identify dynamic parameters of the bone through lab-based experimental study involving artificial bones. Thereafter, physiological damage and decay conditions are artificially simulated in the experimental bones and the same are correlated with changes in conductance signatures from the non-bonded piezo sensor as well as the lead zirconate titanate patch in the conventional adhesively bonded (direct bonding to the subject) configuration. The trend of the conductance signatures in the healthy and the damaged conditions from the non-bonded piezo sensor is found to correlate well with the corresponding signatures from the directly bonded piezo sensor. At the same time, the repeatability of the signatures is also found to be satisfactory. After success in bare bones, the non-bonded piezo sensor configuration is extended to monitor the condition of bones covered with skin and tissue, simulated in the lab with the aid of silicone-based coating. Finally, a proof-of-concept experiment on a live human subject is successfully demonstrated. The overall results of the study demonstrate very good prospects of employing lead zirconate titanate patches in non-bonded piezo sensor mode for monitoring the condition of human bones and other related biomedical subjects.

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A Study on Long-Term In Vitro Reliability of Intracochlear Lead-Zirconate-Titanate Microactuators

Journal of Engineering and Science in Medical Diagnostics and Therapy ◽

10.1115/1.4040103 ◽

2018 ◽

Vol 1 (3) ◽

Author(s):

Yifeng Liu ◽

Chuan Luo ◽

G. Z. Cao ◽

Clifford R. Hume ◽

I. Y. Shen

Keyword(s):

Lead Zirconate Titanate ◽

Electrical Breakdown ◽

Failure Mechanisms ◽

Electrode Array ◽

Lead Zirconate ◽

Acoustic Stimulation ◽

Structural Failure ◽

Significant Drop ◽

Zirconate Titanate

An intracochlear lead-zirconate-titanate (PZT) microactuator integrated with a cochlear implant electrode array could be a feasible strategy to implement combined electric and acoustic stimulation inside the cochlea. The purpose of this paper is to characterize in vitro a prototype PZT microactuator for intracochlear applications, including service life, failure mechanisms, and lead leaching. PZT microactuators were driven sinusoidally to failure in air and in artificial perilymph. Frequency response functions (FRFs) and electrical impedance were monitored. After the PZT microactuators failed, the amount of leached lead was measured via inductive coupled plasma mass spectrometry (ICP-MS). Two failure mechanisms are identified: electrical breakdown and structural failure. The electrical breakdown, possibly from loss of parylene encapsulation, is evidenced by a sudden and significant drop of the actuators' electrical resistance. The structural failure, possibly from electrode delamination, is evidenced by a sudden and significant drop of FRFs. The amount of lead leached from the PZT microactuator is well below published safety guidelines from federal agencies.

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Damage assessment in concrete structures using piezoelectric based sensors

Revista ALCONPAT ◽

10.21041/ra.v7i1.173 ◽

2017 ◽

Vol 7 (1) ◽

pp. 25-35 ◽

Cited By ~ 3

Author(s):

A. Narayanan ◽

K. V. L. Subramaniam

Keyword(s):

Lead Zirconate Titanate ◽

Damage Assessment ◽

Concrete Structures ◽

Electrical Conductance ◽

Mechanical Impedance ◽

Lead Zirconate ◽

Internal Damage ◽

Zirconate Titanate ◽

Resonant Behavior ◽

Damage In Concrete

Damage assessment in concrete structures using piezoelectric based sensorsABSTRACTPiezoelectric 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.Keywords: PZT; electro-mechanical impedance; conductance; microcracks.Evaluación de daños en estructuras de concreto utilizando sensores piezoeléctricosRESUMENLos sensores inteligentes PZT (Lead Zirconate Titanate) basados en piezoeléctricos ofrecen un potencial significativo para monitorear continuamente el desarrollo y la progresión de los daños internos en estructuras de concreto. Se investigan los cambios en el comportamiento resonante a través de la conductancia eléctrica medida, obtenida a partir de la respuesta electromecánica (EM) de un PZT unido a un sustrato de concreto para aumentar los niveles de daño. Los cambios en la resonancia de la conductancia EM se detectan antes de que aparezcan signos visibles de agrietamiento. La desviación cuadrática media de la raíz de la conductancia en los picos resonantes refleja con precisión el nivel de daño en el sustrato. Los hallazgos presentados aquí proporcionan una base para desarrollar una metodología de detección utilizando parches PZT para el monitoreo continuo de estructuras de concreto.Palabras clave: PZT; impedancia electromecánica; conductancia; microfisuras.Avaliação de danos em estruturas de concreto usando sensores piezoelétricos RESUMOOs sensores piezoelétricos inteligentes PZT (Lead Zirconate Titanate) oferecem um potencial significativo para o monitoramento contínuo do desenvolvimento e progressão de danos internos em estruturas de concreto. As alterações de ressonância através da medida da condutância elétrica obtida a partir da resposta eletromecânica (EM) de um PZT ligado a um substrato de concreto é investigada para níveis crescentes de danos. As alterações no perfil de ressonância de condutância EM são detectadas antes de sinais visíveis de fissuras. O desvio quadrático médio da raiz do perfil de condutância nos picos ressonantes é mostrado para refletir com precisão o nível de dano no substrato. Os resultados aqui apresentados fornecem uma base para o desenvolvimento de uma metodologia de detecção usando PZT para monitoramento contínuo de estruturas de concretoPalavras chave: PZT; impedância eletromecânica; condutância; microfissuras.

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Convergent-bceam diffraction studies on lead zirconate titanate Ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143961 ◽

1986 ◽

Vol 44 ◽

pp. 482-483

Author(s):

M.L.A. Dass ◽

T.A. Bielicki ◽

G. Thomas ◽

T. Yamamoto ◽

K. Okazaki

Keyword(s):

Lead Zirconate Titanate ◽

Direct Proof ◽

Lead Zirconate ◽

Subsolidus Phase ◽

Pzt Ceramics ◽

Subsolidus Phase Diagram ◽

Zirconate Titanate ◽

Two Phases ◽

Cbd Method ◽

Titanate Ceramics

Lead zirconate titanate, Pb(Zr,Ti)O3 (PZT), ceramics are ferroelectrics formed as solid solutions between ferroelectric PbTiO3 and ant iferroelectric PbZrO3. The subsolidus phase diagram is shown in figure 1. PZT transforms between the Ti-rich tetragonal (T) and the Zr-rich rhombohedral (R) phases at a composition which is nearly independent of temperature. This phenomenon is called morphotropism, and the boundary between the two phases is known as the morphotropic phase boundary (MPB). The excellent piezoelectric and dielectric properties occurring at this composition are believed to.be due to the coexistence of T and R phases, which results in easy poling (i.e. orientation of individual grain polarizations in the direction of an applied electric field). However, there is little direct proof of the coexistence of the two phases at the MPB, possibly because of the difficulty of distinguishing between them. In this investigation a CBD method was found which would successfully differentiate between the phases, and this was applied to confirm the coexistence of the two phases.

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