scholarly journals Generalized Dynamic Analytical Model of Piezoelectric Materials for Characterization Using Electrical Impedance Spectroscopy

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2502 ◽  
Author(s):  
Hector de Castilla ◽  
Pierre Bélanger ◽  
Ricardo J. Zednik
Keyword(s):  
Analytical Model ◽  
Piezoelectric Materials ◽  
Mechanical Strain ◽  
Impedance Spectrum ◽  
Electrical Impedance Spectroscopy ◽  
Material System ◽  
Daily Lives ◽  
Mechanical And Electrical Properties ◽  
Crystal Class ◽  
Almost All

Piezoelectric materials have the intrinsic reversible ability to convert a mechanical strain into an electric field and their applications touch our daily lives. However, the complex physical mechanisms linking mechanical and electrical properties make these materials hard to understand. Computationally onerous models have historically been unable to adequately describe dynamic phenomena inside real piezoelectric materials, and are often limited to over-simplified first-order analytical, quasi-static, or unsatisfying phenomenological numerical approaches. We present a generalized dynamic analytical model based on first-principles that is efficiently computable and better describes these exciting materials, including higher-order coupling effects. We illustrate the significance of this model by applying it to the important 3m crystal symmetry class of piezoelectric materials that includes lithium niobate, and show that the model accurately predicts the experimentally observed impedance spectrum. This dynamic behavior is a function of almost all intrinsic properties of the piezoelectric material, so that material properties, including mechanical, electrical, and dielectric coefficients, can be readily and simultaneously extracted for any size crystal, including at the nanoscale; the only prior knowledge required is the crystal class of the material system. In addition, the model’s analytical approach is general in nature, and can increase our understanding of traditional and novel ferroelectric and piezoelectric materials, regardless of crystal size or orientation.

FLEXOELECTRIC COMPOSITE — A NEW PROSPECT FOR LEAD-FREE PIEZOELECTRICS

2010 ◽  
Vol 03 (01) ◽  
pp. 79-81 ◽  
Author(s):  
BAOJIN CHU ◽  
WENYI ZHU ◽  
NAN LI ◽  
L. ERIC CROSS
Keyword(s):  
Piezoelectric Properties ◽  
Piezoelectric Materials ◽  
Physical Phenomenon ◽  
Mechanical Strain ◽  
Dielectric Materials ◽  
Electric Polarization ◽  
Lead Free ◽  
Piezoelectric Response ◽  
Bst Ceramics ◽  
Better Than

Flexoelectricity describes the physical phenomenon of the generation of electric polarization from mechanical strain gradient in solid insulators. In common dielectric materials, the flexoelectric coefficient is trivially small ~10-10 C/m. In Ba(Sr,Ti)O 3 (BST) ceramics, flexoelectric coefficient up to 10-4 C/m was observed. Such high coefficient makes it possible to design high piezoelectric response flexoelectric composites. In this letter, we will demonstrate that the newly designed flexoelectric composites could have piezoelectric properties better than conventional piezoelectric materials.

scholarly journals How can we relieve gastrointestinal symptoms in people with cystic fibrosis? An international qualitative survey

2020 ◽  
Vol 7 (1) ◽  
pp. e000614
Author(s):  
Sherie Smith ◽  
Nicola Rowbotham ◽  
Gwyneth Davies ◽  
Katie Gathercole ◽  
Sarah J Collins ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Online Survey ◽  
Gastrointestinal Symptoms ◽  
Daily Lives ◽  
Web Based ◽  
Qualitative Survey ◽  
Gi Symptoms ◽  
James Lind Alliance ◽  
Adults And Children ◽  
Almost All

IntroductionRelieving gastrointestinal (GI) symptoms was identified as a ‘top ten’ priority by our James Lind Alliance Priority Setting Partnership in cystic fibrosis (CF). We conducted an online survey to find out more about the effect of GI symptoms in CF.MethodsWe co-produced an online survey distributed to the CF community via web-based platforms. The survey consisted of open and closed questions designed to help us learn more about the effects of GI symptoms for people with CF (pwCF). We analysed the data using descriptive statistics and thematic analysis. We promoted the survey via social media and web-based platforms which allowed respondents from any country to take part. Our participants came from the CF community, including: adults and children with CF, parents and close family of pwCF and healthcare professionals (HCPs) working with pwCF.ResultsThere were 276 respondents: 90 (33%) pwCF, 79 (29%) family, 107 (39%) HCPs. The most commonly reported symptoms by lay respondents were stomach cramps/pain, bloating and a ‘combination of symptoms’. The top three symptoms that HCPs said were reported to them were reduced appetite, bloating and constipation. Almost all (94% (85/90)) HCPs thought medications helped to relieve GI symptoms but only 58% (82/141) of lay respondents agreed.ConclusionsOur survey has shown that GI symptoms among our participants are prevalent and intrude on daily lives of pwCF. There is a need for well-designed clinical studies to provide better evidence for management of GI symptoms and complications.

scholarly journals Electrical impedance spectroscopy in relation to seed viability and moisture content in snap bean (Phaseolus vulgaris L.)

2002 ◽  
Vol 12 (1) ◽  
pp. 17-29 ◽  
Author(s):  
T. Repo ◽  
D.H. Paine ◽  
A.G. Taylor
Keyword(s):  
Phaseolus Vulgaris ◽  
Impedance Spectroscopy ◽  
Moisture Content ◽  
Electrical Impedance ◽  
Seed Viability ◽  
Impedance Spectrum ◽  
Electrical Circuit ◽  
Electrical Impedance Spectroscopy ◽  
Snap Bean ◽  
Viable Seeds

A method, electrical impedance spectroscopy (EIS), is introduced to study seed viability non-destructively. Snap bean (Phaseolus vulgaris L.) seeds were studied by EIS to determine the most sensitive EIS parameter(s) and the optimal range of moisture content (MC) for separation of viable and non-viable seeds. Hydrated seeds exhibited two impedance arcs in the complex plane at the frequency range from 60 Hz to 8 MHz, and impedance spectra of viable and non-viable seeds differed. The hydrated seeds were best-modelled by an equivalent electrical circuit with two distributed circuit elements in series with a resistor (Voigt model). Moisture content and seed viability had strong effects on the EIS parameters. The most sensitive EIS parameters for detecting the differences between viable and non-viable seeds were the capacitance log(C2), the resistance R2, the resistance ratio R2/R1 and the apex ratio, which all represent specific features of the impedance spectrum. The highest differentiation in the EIS parameters between the viable and non-viable seeds occurred in partially imbibed seeds between MC of 40 and 45% (fresh weight basis).

Modeling and Simulation of Monocrystal Piezoelectric Generator

2013 ◽  
Vol 785-786 ◽  
pp. 1203-1207
Author(s):  
Lei Zhang ◽  
Li Qing Fang ◽  
De Qing Guo ◽  
Yong Chao Chen
Keyword(s):  
Modeling And Simulation ◽  
Numerical Method ◽  
Analytical Model ◽  
Piezoelectric Materials ◽  
Mechanical Vibration ◽  
Adhesive Layer ◽  
Operation Mechanism ◽  
Material Parameters ◽  
Voltage Stress ◽  
Piezoelectric Generator

The expressions of voltage, stress and amount of charge of monocrystal piezoelectric generator under concentrated exterior pressure was derived in order to proving the precision and validity of numerical method applied to piezoelectric materials' distribution sensing and the study of operation mechanism ignore the influence of adhesive layer. An analytical model of the monocrystal piezoelectric generator was established by using the mechanical vibration theory. And the effects of the structural and material parameters on the output energy are analyzed.

scholarly journals Thematic Dynamics of Internet of Things (IoT): Impact on Digital Personalized Healthcare (PHC)

2021 ◽  
Author(s):  
Bongs Lainjo
Keyword(s):  
Artificial Intelligence ◽  
Machine Learning ◽  
Data Mining ◽  
Successful Implementation ◽  
Daily Lives ◽  
Personalized Healthcare ◽  
Iot Platform ◽  
Iot Platforms ◽  
Almost All

Abstract Background: Information technology has continued to shape contemporary thematic trends. Advances in communication have impacted almost all themes ranging from education, engineering, healthcare, and many other aspects of our daily lives. Method: This paper attempts to review the different dynamics of the thematic IoT platforms. A select number of themes are extensively analyzed with emphasis on data mining (DM), personalized healthcare (PHC), and thematic trends of a select number of subjectively identified IoT-related publications over three years. In this paper, the number of IoT-related-publications is used as a proxy representing the number of apps. DM remains the trailblazer, serving as a theme with crosscutting qualities that drive artificial intelligence (AI), machine learning (ML), and data transformation. A case study in PHC illustrates the importance, complexity, productivity optimization, and nuances contributing to a successful IoT platform. Among the initial 99 IoT themes, 18 are extensively analyzed using the number of IoT publications to demonstrate a combination of different thematic dynamics, including subtleties that influence escalating IoT publication themes. Results: Based on findings amongst the 99 themes, the annual median IoT-related publications for all the themes over the four years were increasingly 5510, 8930, 11700, and 14800 for 2016, 2017, 2018, and 2019 respectively; indicating an upbeat prognosis of IoT dynamics. Conclusion: The vulnerabilities that come with the successful implementation of IoT systems are highlighted including the successes currently achieved by institutions promoting the benefits of IoT-related systems like the case study. Security continues to be an issue of significant importance.

scholarly journals Development of Smart Shoes Using Piezoelectric Material

2021 ◽  
Vol 7 (1) ◽  
pp. 49-55
Author(s):  
Affa Rozana Abdul Rashid ◽  
Nur Insyierah Md Sarif ◽  
Khadijah Ismail
Keyword(s):  
Piezoelectric Material ◽  
Alternative Energy ◽  
Piezoelectric Materials ◽  
Mechanical Energy ◽  
Electronic Devices ◽  
Electrical Energy ◽  
Small Scale ◽  
Power Electronic ◽  
Energy Harvesters ◽  
Almost All

The consumption of low-power electronic devices has increased rapidly, where almost all applications use power electronic devices. Due to the increase in portable electronic devices’ energy consumption, the piezoelectric material is proposed as one of the alternatives of the significant alternative energy harvesters. This study aims to create a prototype of “Smart Shoes” that can generate electricity using three different designs embedded by piezoelectric materials: ceramic, polymer, and a combination of both piezoelectric materials. The basic principle for smart shoes’ prototype is based on the pressure produced from piezoelectric material converted from mechanical energy into electrical energy. The piezoelectric material was placed into the shoes’ sole, and the energy produced due to the pressure from walking, jogging, and jumping was measured. The energy generated was stored in a capacitor as piezoelectric material produced a small scale of energy harvesting. The highest energy generated was produced by ceramic piezoelectric material under jumping activity, which was 1.804 mJ. Polymer piezoelectric material produced very minimal energy, which was 55.618 mJ. The combination of both piezoelectric materials produced energy, which was 1.805 mJ from jumping activity.

scholarly journals Smartphones e o ensino de química orgânica: o uso de jogos pode influenciar no aprendizado?

2019 ◽  
Vol 1 (44) ◽  
pp. 192
Author(s):  
Antônia Vanúzia Nunes da Silva Araújo ◽  
Ayla Marcia Márcia Cordeiro Bizerra ◽  
Demétrios Araújo Magalhães Coutinho
Keyword(s):  
Organic Chemistry ◽  
Public School ◽  
Mobile Devices ◽  
Teaching And Learning ◽  
Daily Lives ◽  
Positive Approach ◽  
Almost All ◽  
The City ◽  
Google Play ◽  
Learning Chemistry

The process of teaching and learning chemistry is still considered difficult, for even with all the technology available for its improvement, this same issue is responsible for students’ distraction in class. The most common example are smartphones, which are devices that are increasingly versatile and have been inserted into the daily lives of almost all people. The use of mobile devices in the classroom can be a useful alternative for teachers to overcome the difficulties inherent in this process. This paper aims to present the contribution of educational android games in the process of learning organic functions at a public school in the city of Pau dos Ferros (RN). Initially, we use the Google Play Store® platform to check the availability of games dealing with organic chemistry topics. We choose four applications to be used as a supplementary methodology for solving exercises related to organic chemistry. Furthermore, we collected students’ opinions regarding the method used. We observed that these devices when used in a controlled, planned and an appropriate way can contribute to a positive approach to the motivation and interest of students during class.

scholarly journals Development of an Elastic, Electrically Conductive Coating for TPU Filaments

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7158
Author(s):  
Henriette Grellmann ◽  
Mathis Bruns ◽  
Felix Michael Lohse ◽  
Iris Kruppke ◽  
Andreas Nocke ◽  
...  
Keyword(s):  
Thermoplastic Polyurethane ◽  
Mechanical Strain ◽  
Special Focus ◽  
Electrically Conductive ◽  
Mechanical And Electrical Properties ◽  
Elastic Filaments ◽  
Wide Range ◽  
Conductive Fibers ◽  
Multifilament Yarns ◽  
Conductive Particles

Electrically conductive filaments are used in a wide variety of applications, for example, in smart textiles and soft robotics. Filaments that conduct electricity are required for the transmission of energy and information, but up until now, most electrically conductive fibers, filaments and wires offer low mechanical elongation. Therefore, they are not well suited for the implementation into elastomeric composites and textiles that are worn close to the human body and have to follow a wide range of movements. In order to overcome this issue, the presented study aims at the development of electrically conductive and elastic filaments based on a coating process suited for multifilament yarns made of thermoplastic polyurethane (TPU). The coating solution contains TPU, carbon nanotubes (CNT) and N-Methyl-2-pyrrolidone (NMP) with varied concentrations of solids and electrically conductive particles. After applying the coating to TPU multifilament yarns, the mechanical and electrical properties are analyzed. A special focus is given to the electromechanical behavior of the coated yarns under mechanical strain loading. It is determined that the electrical conductivity is maintained even at elongations of up to 100%.

scholarly journals Representation of real-world event schemas during narrative perception

2018 ◽  
Author(s):  
Christopher Baldassano ◽  
Uri Hasson ◽  
Kenneth A. Norman
Keyword(s):  
Human Subjects ◽  
Brain Activity ◽  
Temporal Structure ◽  
Animal Experiments ◽  
Situation Model ◽  
Brain Regions ◽  
Control Group ◽  
Daily Lives ◽  
High Level ◽  
Almost All

AbstractUnderstanding movies and stories requires maintaining a high-level situation model that abstracts away from perceptual details to describe the location, characters, actions, and causal relationships of the currently unfolding event. These models are built not only from information present in the current narrative, but also from prior knowledge about schematic event scripts, which describe typical event sequences encountered throughout a lifetime. We analyzed fMRI data from 44 human subjects presented with sixteen three-minute stories, consisting of four schematic events drawn from two different scripts (eating at a restaurant or going through the airport). Aside from this shared script structure, the stories varied widely in terms of their characters and storylines, and were presented in two highly dissimilar formats (audiovisual clips or spoken narration). One group was presented with the stories in an intact temporal sequence, while a separate control group was presented with the same events in scrambled order. Regions including the posterior medial cortex, medial prefrontal cortex (mPFC), and superior frontal gyrus exhibited schematic event patterns that generalized across stories, subjects, and modalities. Patterns in mPFC were also sensitive to overall script structure, with temporally scrambled events evoking weaker schematic representations. Using a Hidden Markov Model, patterns in these regions can predict the script (restaurant vs. airport) of unlabeled data with high accuracy, and can be used to temporally align multiple stories with a shared script. These results extend work on the perception of controlled, artificial schemas in human and animal experiments to naturalistic perception of complex narrative stimuli.Significance StatementIn almost all situations we encounter in our daily lives, we are able to draw on our schematic knowledge about what typically happens in the world to better perceive and mentally represent our ongoing experiences. In contrast to previous studies that investigated schematic cognition using simple, artificial associations, we measured brain activity from subjects watching movies and listening to stories depicting restaurant or airport experiences. Our results reveal a network of brain regions that is sensitive to the shared temporal structure of these naturalistic situations. These regions abstract away from the particular details of each story, activating a representation of the general type of situation being perceived.

scholarly journals Effects of Lead Exposure on Blood Electrical Impedance Spectroscopy of Mice

2021 ◽  
Author(s):  
Binying Yang ◽  
Jia Xu ◽  
Shao Hu ◽  
Boning You ◽  
Qing Ma
Keyword(s):  
Electrical Properties ◽  
Impedance Spectroscopy ◽  
Lead Exposure ◽  
Electrical Impedance ◽  
Equivalent Circuit Model ◽  
Impedance Spectrum ◽  
Nyquist Plot ◽  
Electrical Impedance Spectroscopy ◽  
Impedance Method ◽  
Range Data

Abstract Background: Lead is a nonessential heavy metal, which can inhibit heme synthesis and has significant cytotoxic effects. Nevertheless, its effect on the electrical properties of red blood cells (RBCs) remains unclear. Consequently, this study aimed to investigate the electrical properties and the electrophysiological mechanism of lead exposure in mouse blood using Electrical Impedance Spectroscopy (EIS). Methods: AC impedance method was used to measure the electrical impedance of healthy and lead exposure blood of mice in 0.01-100 MHz frequency range. Data characteristic of the impedance spectrum, Bodes plot, Nyquist plot and Nichols plot, and three elements equivalent circuit model were used to explicitly analyze the differences in amplitude-frequency, phase-frequency, and the frequency characteristic of blood in electrical impedance properties. Results: Compared with the healthy blood in control mice, the changes in blood exposed to lead was as follows: (I) the hematocrit decreased; (II) the amplitude-frequency and phase-frequency characteristics of electrical impedance decreased; (III) the characteristic frequencies ( f 0 ) were significantly increased; (IV) the electrical impedance of plasma, erythrocyte membrane, and hemoglobin decreased, while the conductivity increased. Conclusion: Therefore, EIS can be used as an effective method to monitor blood and RBCs abnormalities caused by lead-exposure.

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