Validation and Characterization of an Acoustic Sensor Based on PVDF Micropillars and Patterned Electrodes

2010 ◽  
Author(s):  
Jian Xu ◽  
Marcelo J. Dapino ◽  
Daniel Gallego-Perez ◽  
Derek Hansford
Keyword(s):  
Acoustic Waves ◽  
Polyvinylidene Fluoride ◽  
Notch Filter ◽  
Design Principles ◽  
Pvdf Film ◽  
Acoustic Sensor ◽  
Gap Ratio ◽  
Patterned Electrodes ◽  
The Individual

This paper addresses the fabrication, validation, and characterization of a millimeter-size acoustic sensor consisting of Polyvinylidene Fluoride (PVDF) micropillars and patterned electrodes. The sensor takes advantage of two key design principles: stress amplification through the area ratio between the overall surface exposed to acoustic waves and the area of the individual micropillars, and patterned electrodes which reduce the capacitance of the sensor by excluding the capacitance of the air between micropillars. In combination, these design principles enable a sensor capable of achieving 100× the sensitivity of flat PVDF film. A sensitivity analysis is presented and sensor fabrication details are described. An experimental setup was developed to characterize the sensor against a reference microphone. A signal conditioning circuit including a preamplifier circuit and a notch filter was designed and constructed. Sensitivity calibration tests show that a micropillar array with a gap ratio of 5.82 exhibits a stress constant g33 = −19.93 V/m/Pa, which is 60.39 times greater than the stress constant of commercial PVDF film. Experimental results also show that the sensitivity of the sensor is in close agreement with theory, thus confirming the performance advantages of the micropillar sensor.

Acoustic Sensor With PVDF Micro-Pillars and Patterned Electrodes

2008 ◽  
Author(s):  
Jian Xu ◽  
Marcelo J. Dapino ◽  
Daniel Gallego Perez ◽  
Derek Hansford
Keyword(s):  
Theoretical Analysis ◽  
Optimization Algorithm ◽  
Polyvinylidene Fluoride ◽  
Dynamic Range ◽  
Acoustic Sensor ◽  
Frequency Bandwidth ◽  
Electrical Parameters ◽  
New Type ◽  
Patterned Electrodes ◽  
Micro Pillars

This paper addresses the design and theoretical analysis of a new type of millimeter-size acoustic sensor that uses Polyvinylidene Fluoride (PVDF) micro-pillars and patterned electrodes. The sensor has the potential to achieve 100x the sensitivity of existing commercial sensors in combination with a dynamic range of 181dB and a frequency bandwidth of at least 100 kHz. A constrained optimization algorithm has been developed as a function of geometric parameters (sensor footprint, diameter and height of the micro-pillars, gap between pillar edges, number of pillars) and electrical parameters of the sensor and conditioning amplifier.

Design of Beam Surface Displacement Sensors

2014 ◽  
Author(s):  
Rohan Thomas ◽  
Marcellin Zahui
Keyword(s):  
Polyvinylidene Fluoride ◽  
Lateral Displacement ◽  
Surface Displacement ◽  
Pvdf Film ◽  
Displacement Curve ◽  
Various Boundary Conditions ◽  
Displacement Sensors ◽  
Beam Surface ◽  
The Individual ◽  
Constant Shape

PolyVinyliDene Fluoride (PVDF) film is used in this work to develop surface displacement sensors for vibrating simply supported, clamped, and cantilever beams. The constant shape PVDF film is bonded to the surface of the beam spanning the entire beam length. Bands parallel to the width of the beam are etched on the film to create multiple separate sections of the sensor. The individual output charge of the sensor sections is proportional to the slope of the beam lateral displacement curve of that patch. The actual beam surface displacement curve is calculated from these slopes. Theoretical analysis and numerical simulation show that the proposed sensor can be used to effectively measure the lateral vibration displacements of prismatic beams with various boundary conditions. However the accuracy of the measurement is closely related to the number of sensor sections and thus, relatively large number of channels is required for accurate measurements.

Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 86-87
Author(s):  
Kemining W. Yeh ◽  
Richard S. Muller ◽  
Wei-Kuo Wu ◽  
Jack Washburn
Keyword(s):  
Integrated Circuit ◽  
Acoustic Waves ◽  
New Technology ◽  
Surface Acoustic Waves ◽  
Electromechanical Properties ◽  
Leading Role ◽  
Saw Devices ◽  
Transmission Electron ◽  
High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

Preparation and Characterization of Polyvinylidene Fluoride/ZrO2-TiO2 Optical Film with Wide Band Gap and High Refractive Index

2013 ◽  
Vol 28 (6) ◽  
pp. 671-676 ◽  
Author(s):  
Yu-Qing ZHANG ◽  
Li-Li ZHAO ◽  
Shi-Long XU ◽  
Chao ZHANG ◽  
Xiao-Ying CHEN ◽  
...  
Keyword(s):  
Refractive Index ◽  
Band Gap ◽  
Polyvinylidene Fluoride ◽  
Wide Band ◽  
High Refractive Index ◽  
Wide Band Gap ◽  
Optical Film

Separation and Characterization of Standard Propoxyphene Diastereomers and Their Determination in Pharmaceutical and Illicit Preparations

1981 ◽  
Vol 64 (4) ◽  
pp. 875-883
Author(s):  
Shiv K Soni ◽  
Daniel Van Gelder
Keyword(s):  
High Pressure ◽  
Optical Isomers ◽  
Gold Chloride ◽  
Melting Points ◽  
Eutectic Melting ◽  
Racemic Mixtures ◽  
The Individual ◽  
Isomeric Mixtures ◽  
Asymmetric Carbon

Abstract Due to the existence of 2 asymmetric carbon atoms in: the propoxyphene molecule, there are 4 diastereomers: alpha dextro, alpha levo, beta dextro, and beta levo. Only α-d-propoxyphene is included under the federal Controlled Substances Act. Baseline separations of propoxyphene from various incipients (aspirin, caffeine, phenacetin, and acetaminophen) present in pharmaceutical and illicit preparations, and between the alpha and beta diastereomers, were achieved by high pressure liquid chromatography. The column eluant was collected and propoxyphene was extracted. The optical isomers were differentiated and characterized by melting points and by chemical microcrystalline tests. Using hot stage thermomicroscopy, the eutectic melting points of binary isomeric mixtures of propoxyphene bases and salts were found to be depressed about 10° and 15-30°C, respectively, below the individual isomer melting points. The characteristic microcrystals formed with the alpha racemic mixtures by using a glycerin-aqueous gold chloride reagent were not produced by the beta racemic mixtures.

scholarly journals Does higher education properly prepare graduates for the growing artificial intelligence market? Gaps identification using text mining

2021 ◽  
pp. 1-13
Author(s):  
Lamiae Benhayoun ◽  
Daniel Lang
Keyword(s):  
Artificial Intelligence ◽  
Natural Language Processing ◽  
Text Mining ◽  
Natural Language ◽  
Language Processing ◽  
Academic Training ◽  
Market Requirements ◽  
Job Advertisements ◽  
The Individual

BACKGROUND: The renewed advent of Artificial Intelligence (AI) is inducing profound changes in the classic categories of technology professions and is creating the need for new specific skills. OBJECTIVE: Identify the gaps in terms of skills between academic training on AI in French engineering and Business Schools, and the requirements of the labour market. METHOD: Extraction of AI training contents from the schools’ websites and scraping of a job advertisements’ website. Then, analysis based on a text mining approach with a Python code for Natural Language Processing. RESULTS: Categorization of occupations related to AI. Characterization of three classes of skills for the AI market: Technical, Soft and Interdisciplinary. Skills’ gaps concern some professional certifications and the mastery of specific tools, research abilities, and awareness of ethical and regulatory dimensions of AI. CONCLUSIONS: A deep analysis using algorithms for Natural Language Processing. Results that provide a better understanding of the AI capability components at the individual and the organizational levels. A study that can help shape educational programs to respond to the AI market requirements.

scholarly journals Material Geometry of Binary Composites

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 892
Author(s):  
Marcelo Epstein
Keyword(s):  
Continuum Mechanics ◽  
Mathematical Framework ◽  
Double Groupoid ◽  
The Individual ◽  
Elastic Composites

The constitutive characterization of the uniformity and homogeneity of binary elastic composites is presented in terms of a combination of the material groupoids of the individual constituents. The incorporation of these two groupoids within a single double groupoid is proposed as a viable mathematical framework for a unified formulation of this and similar kinds of problems in continuum mechanics.

scholarly journals Preclinical Testing of Radiopharmaceuticals for the Detection and Characterization of Osteomyelitis: Experiences from a Porcine Model

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4221
Author(s):  
Aage Kristian Olsen Alstrup ◽  
Svend Borup Jensen ◽  
Ole Lerberg Nielsen ◽  
Lars Jødal ◽  
Pia Afzelius
Keyword(s):  
Animal Model ◽  
Animal Models ◽  
Porcine Model ◽  
Animal Experiments ◽  
Radioactive Tracers ◽  
The Individual ◽  
Selection Of

The development of new and better radioactive tracers capable of detecting and characterizing osteomyelitis is an ongoing process, mainly because available tracers lack selectivity towards osteomyelitis. An integrated part of developing new tracers is the performance of in vivo tests using appropriate animal models. The available animal models for osteomyelitis are also far from ideal. Therefore, developing improved animal osteomyelitis models is as important as developing new radioactive tracers. We recently published a review on radioactive tracers. In this review, we only present and discuss osteomyelitis models. Three ethical aspects (3R) are essential when exposing experimental animals to infections. Thus, we should perform experiments in vitro rather than in vivo (Replacement), use as few animals as possible (Reduction), and impose as little pain on the animal as possible (Refinement). The gain for humans should by far exceed the disadvantages for the individual experimental animal. To this end, the translational value of animal experiments is crucial. We therefore need a robust and well-characterized animal model to evaluate new osteomyelitis tracers to be sure that unpredicted variation in the animal model does not lead to a misinterpretation of the tracer behavior. In this review, we focus on how the development of radioactive tracers relies heavily on the selection of a reliable animal model, and we base the discussions on our own experience with a porcine model.

scholarly journals Generating Electricity from Natural Evaporation Using PVDF Thin Films Incorporating Nanocomposite Materials

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 585
Author(s):  
Ariel Ma ◽  
Jian Yu ◽  
William Uspal
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Polyvinylidene Fluoride ◽  
Capillary Flow ◽  
Short Circuit ◽  
Current Source ◽  
Nanocomposite Materials ◽  
The Other ◽  
Pvdf Film ◽  
Ambient Conditions

Natural evaporation has recently come under consideration as a viable source of renewable energy. Demonstrations of the validity of the concept have been reported for devices incorporating carbon-based nanocomposite materials. In this study, we investigated the possibility of using polymer thin films to generate electricity from natural evaporation. We considered a polymeric system based on polyvinylidene fluoride (PVDF). Porous PVDF films were created by incorporating a variety of nanocomposite materials into the polymer structure through a simple mixing procedure. Three nanocomposite materials were considered: carbon nanotubes, graphene oxide, and silica. The evaporation-induced electricity generation was confirmed experimentally under various ambient conditions. Among the nanocomposite materials considered, mesoporous silica (SBA-15) was found to outperform the other two materials in terms of open-circuit voltage, and graphene oxide generated the highest short-circuit current. It was found that the nanocomposite material content in the PVDF film plays an important role: on the one hand, if particles are too few in number, the number of channels will be insufficient to support a strong capillary flow; on the other hand, an excessive number of particles will suppress the flow due to excessive water absorption underneath the surface. We show that the device can be modeled as a simple circuit powered by a current source with excellent agreement between the theoretical predictions and experimental data.

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