Ice Pressure Measurements Using PVDF Film

1990 ◽  
Vol 112 (1) ◽  
pp. 91-95
Author(s):  
A. Joensuu
Keyword(s):  
Polyvinylidene Fluoride ◽  
Mechanical Deformation ◽  
Pvdf Film ◽  
Pressure Measurements ◽  
Measuring Devices ◽  
Contact Surfaces ◽  
Ice Pressure ◽  
Complicated Geometries ◽  
Shed Light ◽  
Signal Treatment

Piezoelectric ice pressure measuring devices have been constructed using polyvinylidene fluoride (PVDF) film. PVDF seems to be an appealing transducer material since it is light, thin, mechanically resistant and can be attached on surfaces with complicated geometries. Moreover, it is commercially available in large sheets. Dynamic ice pressure distribution can be monitored using various metalization patterns thus dividing the areas into many active cells. Because minimum mechanical deformation is needed for the piezoelectric phenomenon to take place, the device does not interfere with the quantity to be measured. It is believed that the material will help to shed light on the ice pressure formation process in crushing. The paper deals with full-scale experiments conducted using PVDF film on the contact surfaces of a test hammer and a cylindrical indentor, and describes the signal treatment used.

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.

Research on PVDF Micro-Force Sensor

2014 ◽  
Vol 599-601 ◽  
pp. 1135-1138
Author(s):  
Chao Zhe Ma ◽  
Jin Song Du ◽  
Yi Yang Liu
Keyword(s):  
Power Dissipation ◽  
Polyvinylidene Fluoride ◽  
High Sensitivity ◽  
Force Sensor ◽  
Calibration Method ◽  
Pvdf Film ◽  
Force Sensors ◽  
Low Power Dissipation ◽  
Micro Force Sensor ◽  
Processing Circuit

At present, sub-micro-Newton (sub-μN) micro-force in micro-assembly and micro-manipulation is not able to be measured reliably. The piezoelectric micro-force sensors offer a lot of advantages for MEMS applications such as low power dissipation, high sensitivity, and easily integrated with piezoelectric micro-actuators. In spite of many advantages above, the research efforts are relatively limited compared to piezoresistive micro-force sensors. In this paper, Sensitive component is polyvinylidene fluoride (PVDF) and the research object is micro-force sensor based on PVDF film. Moreover, the model of micro-force and sensor’s output voltage is built up, signal processing circuit is designed, and a novel calibration method of micro-force sensor is designed to reliably measure force in the range of sub-μN. The experimental results show the PVDF sensor is designed in this paper with sub-μN resolution.

ELECTROMECHANICAL CHARACTERISTICS OF POLYVINYLIDENE FLUORIDE FOR FLEXIBLE ELECTRONICS

2013 ◽  
Vol 37 (3) ◽  
pp. 325-333 ◽  
Author(s):  
Wen-Yang Chang ◽  
Cheng-Hung Hsu
Keyword(s):  
Flexible Electronics ◽  
Polyvinylidene Fluoride ◽  
Input Voltage ◽  
Pvdf Film ◽  
Resistive Load ◽  
X Ray Diffraction ◽  
Leakage Currents ◽  
Current Voltage ◽  
Current Voltage Characteristics ◽  
Stress Cycles

The electromechanical characteristics of PVDF are investigated, including the crystallization, frequency responses, hysteresis, leakage currents, current-voltage characteristics, and fatigue characteristics using X-ray diffraction and an electrometer. Results show that the frequency band of PVDF increases with increasing resistive load and capacitance. The hysteresis area of ΔH slightly increases with increasing input voltage. The magnitude of the current values increases with decreasing delay time at a given drive voltage. PVDF film induced larger degradation when the number of stress cycles was increased to about 105 cumulative cycles.

A Dynamic Calibration Test on PVDF Film Pressure Sensor with Dropping Hammer Method

2014 ◽  
Vol 933 ◽  
pp. 548-553 ◽  
Author(s):  
Yong Qiang Wang ◽  
Ying Lin Xiao
Keyword(s):  
Polyvinylidene Fluoride ◽  
Piezoelectric Materials ◽  
Dynamic Pressure ◽  
High Sensitivity ◽  
Pvdf Film ◽  
Piezoelectric Film ◽  
High Mechanical Strength ◽  
Response Range ◽  
New Type ◽  
Shock Wave Pressure

Polyvinylidene Fluoride (referred to as PVDF) piezoelectric film is a new type of polymer piezoelectric materials. Because of its light weight, thin thickness, high sensitivity, high mechanical strength, wide frequency response range and other advantages, it has the application prospect in the explosion field. In this article, film sensors were made based on the PVDF piezoelectric film, and its role in the sensors is the sensitive element. The result of the low dynamic pressure calibration tests showed that it has a very high linear degree and good reproducibility, so that it can be used for low-pressure section of the shock wave pressure measurement.

INVESTIGATING THE EFFECT OF THE ORTHOTROPIC PROPERTY OF PIEZOELECTRIC PVDF

2007 ◽  
Vol 31 (1) ◽  
pp. 111-125 ◽  
Author(s):  
S. Sokhanvar ◽  
A. Zabihollah ◽  
R. Sedaghati
Keyword(s):  
Polyvinylidene Fluoride ◽  
Poisson Ratio ◽  
Optimization Procedure ◽  
Pvdf Film ◽  
The Finite Element Method ◽  
Sensory Mode ◽  
Actuation Mode ◽  
The Difference ◽  
Nodal Displacements ◽  
Orthotropic Behavior

The applications of the piezoelectric Polyvinylidene Fluoride, PVDF, integrated with the beams, plates, and membranes, performing as sensor, actuator or combination have been received considerable attention in the recent years. However, not much work has been reported on the influence of the PVDF’s orthotropic behavior, particularly the effect of the orientation of the PVDF film in the host structure, on the performance of the system. In the present study, the effect of the piezoelectric PVDF film orientation on the output voltage, the actuation force, and the dynamic response of the integrated structures has been studied using the finite element method. In the sensory mode, the difference between the output voltages obtained from the biaxial piezoelectric PVDF film and uniaxial one, when the orientation of the film varies from 0 to 90 degree, is investigated. In each case the proportion contributions of the involved piezoelectric coefficients including d31, d32 and are studied. Alternatively, in the actuation mode, the effect of orthotropic behavior of the actuator on the nodal displacements has been taken into consideration. The influence of the material orthotropic property of the transducer on the free undamped response of the system is also investigated. Moreover an effective Young’s modulus and effective Poisson ratio for the uniaxial PVDF film has been introduced using an optimization procedure to minimize the error caused by isotropic assumption of uniaxial PVDF film.

scholarly journals Effect of fabrication technique on the crystalline phase and electrical properties of PVDF films

2015 ◽  
Vol 33 (1) ◽  
pp. 157-162 ◽  
Author(s):  
P. K. Mahato ◽  
A. Seal ◽  
S. Garain ◽  
S. Sen
Keyword(s):  
Polyvinylidene Fluoride ◽  
Tape Casting ◽  
Dimethyl Formamide ◽  
Pvdf Film ◽  
X Ray Diffraction ◽  
Β Phase ◽  
Cast Films ◽  
Solvent Cast ◽  
Ft Ir ◽  
Ferroelectric Hysteresis

AbstractThe effect of different fabrication techniques on the formation of electroactive β-phase polyvinylidene fluoride (PVDF) has been investigated. Films with varying concentration of PVDF and solvent - dimethyl formamide (DMF) were synthesized by tape casting and solvent casting techniques. The piezoelectric β-phase as well as non polar β-phase were observed for both the tape cast and solvent cast films from X-ray diffraction (XRD) micrographs and Fourier transform infra-red spectroscopy (FT-IR) spectra. A maximum percentage (80 %) of β-phase was obtained from FT-IR analysis for a solvent cast PVDF film. The surface morphology of the PVDF films was analyzed by FESEM imaging. The dielectric properties as a function of temperature and frequency and the ferroelectric hysteresis loop as a function of voltage were measured. An enhancement in the value of the dielectric constant and polarization was obtained in solvent cast films.

A comparison of CAT Doppler and oscillometric Memoprint machines for non-invasive blood pressure measurement in conscious cats

2005 ◽  
Vol 7 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Rosanne E. Jepson ◽  
Vivien Hartley ◽  
Michael Mendl ◽  
Sarah ME Caney ◽  
David J Gould
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Diastolic Blood Pressure ◽  
Blood Pressure Measurement ◽  
Systemic Hypertension ◽  
Pressure Measurements ◽  
Non Invasive ◽  
Measuring Devices ◽  
Oscillometric Device ◽  
Significant Difference

Indirect blood pressure measurements were compared in 28 conscious cats using Doppler and oscillometric blood pressure-measuring devices. Ten cats were used to compare Doppler measurements between two examiners and 18 cats were used to compare Doppler and oscillometric measurements. The Doppler machine obtained systolic and diastolic blood pressure readings in 100% and 51% of attempts, respectively. With the oscillometric machine, systolic and diastolic blood pressure readings were obtained in 52% of the attempts. With the Doppler, measures of mean systolic blood pressure between two examiners were positively correlated, but there was no correlation for diastolic blood pressure measures. When comparing the results obtained by Doppler and oscillometric machines there was no significant difference between mean systolic blood pressure readings, but the oscillometric machine produced significantly higher estimates of diastolic blood pressure. In both cases, the standard deviations for the oscillometric machine were considerably larger than those for the Doppler machine. The first reading of systolic blood pressure obtained with the Doppler machine was an excellent predictor of the mean of five readings, but this was not so for the oscillometric machine. It took less than 5 min to obtain five readings in 37.5% of cases with the Doppler machine but this was true for only 5% of cases with the oscillometric machine. Two cats with ophthalmological lesions consistent with systemic hypertension were identified. In these two patients, systolic blood pressure measurements were between 200 and 225 mmHg when measured by Doppler, and between 140 and 150 mmHg when measured by the oscillometric machine. This suggests that a lower reference range for normal systolic blood pressure values should be used for the oscillometric device.

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