Tunable actuation of dielectric elastomer by electromechanical loading rates

2017 ◽  
Vol 111 (18) ◽  
pp. 181901 ◽  
Author(s):  
Guorui Li ◽  
Mingqi Zhang ◽  
Xiangping Chen ◽  
Xuxu Yang ◽  
Tuck-Whye Wong ◽  
...  
Keyword(s):  
Dielectric Elastomer ◽  
Loading Rates ◽  
Electromechanical Loading

scholarly journals Delayed electromechanical instability of a viscoelastic dielectric elastomer balloon

2019 ◽  
Vol 475 (2229) ◽  
pp. 20190316 ◽  
Author(s):  
Xiongfei Lv ◽  
Liwu Liu ◽  
Jinsong Leng ◽  
Yanju Liu ◽  
Shengqiang Cai
Keyword(s):  
Hoop Stress ◽  
Mechanical Load ◽  
Viscoelastic Model ◽  
Dielectric Elastomer ◽  
Time Dependent ◽  
Convex Shape ◽  
Nonlinear Viscoelastic ◽  
Electromechanical Instability ◽  
Electromechanical Loading ◽  
Nonlinear Viscoelastic Model

When a dielectric elastomer (DE) balloon is subjected to electromechanical loading, instability may happen. In recent experiments, it has been shown that the instability configuration of a DE balloon under electromechanical loading can be very different from that only subjected to mechanical load. It has also been observed in the experiments that the electromechanical instability phenomena of a DE balloon can be highly time-dependent. In this article, we adopt a nonlinear viscoelastic model for the DE membrane to investigate the time-dependent electromechanical instability of a DE balloon. Using the model, we show that under a constant electromechanical loading, a DE balloon may gradually evolve from a convex shape to a non-convex shape with bulging out in the centre, and compressive hoop stress can also gradually develop the balloon, resulting in wrinkles as observed in the experiments. We have further shown that the snap-through instability phenomenon of the DE balloon also greatly depends on the ramping rate of the applied voltage.

Uncertainty analysis of dielectric elastomer membranes under electromechanical loading

2019 ◽  
Vol 28 (5) ◽  
pp. 055027
Author(s):  
W Gao ◽  
P R Miles ◽  
A G Moura ◽  
M Y Hussaini ◽  
W S Oates
Keyword(s):  
Uncertainty Analysis ◽  
Dielectric Elastomer ◽  
Electromechanical Loading

scholarly journals Shape Bifurcation of a Spherical Dielectric Elastomer Balloon Under the Actions of Internal Pressure and Electric Voltage

2015 ◽  
Vol 82 (10) ◽  
Author(s):  
Xudong Liang ◽  
Shengqiang Cai
Keyword(s):  
Internal Pressure ◽  
Pressure Control ◽  
Dielectric Elastomer ◽  
Ideal Gas ◽  
Control Mode ◽  
Linear Perturbation ◽  
Electric Voltage ◽  
Equilibrium Configurations ◽  
Nonspherical Shape ◽  
Electromechanical Loading

Under the actions of internal pressure and electric voltage, a spherical dielectric elastomer balloon usually keeps a sphere during its deformation, which has also been assumed in many previous studies. In this article, using linear perturbation analysis, we demonstrate that a spherical dielectric elastomer balloon may bifurcate to a nonspherical shape under certain electromechanical loading conditions. We also show that with a nonspherical shape, the dielectric elastomer balloon may have highly inhomogeneous electric field and stress/stretch distributions, which can lead to the failure of the system. In addition, we conduct stability analysis of the dielectric elastomer balloon in different equilibrium configurations by evaluating its second variation of free energy under arbitrary perturbations. Our analyses indicate that under pressure-control and voltage-control modes, nonspherical deformation of the dielectric elastomer balloon is energetically unstable. However, under charge-control or ideal gas mass-control mode, nonspherical deformation of the balloon is energetically stable.

RESEARCH AND EVALUATE TREATMENT EFFICIENCY ON TAPIOCA PROCESSING INDUSTRIAL WASTEWATER BY AEROBIC BIOFILTER TECHNOLOGY WITH VARIOUS MATERIALS

2010 ◽  
Vol 13 (3) ◽  
pp. 54-66
Author(s):  
Phuong Thi Thanh Nguyen ◽  
Phuoc Van Nguyen ◽  
Anh Cam Thieu
Keyword(s):  
Wastewater Treatment ◽  
Industrial Wastewater ◽  
Utilization Rate ◽  
Organic Loading ◽  
Treatment Efficiency ◽  
Research Results ◽  
Loading Rates

This study was performed to evaluate the efficiency of tapioca processing wastewater treatment using aerobic biofilter with variety of biofilter media: coir, coal, PVC plastic and Bio - Ball BB15 plastic. Research results in the lab demonstrated all four aerobic biofilter models processed can treated completely N and COD which COD reached 90-98% and N reached 61-92%, respectively, at the organic loading rates in range of 0.5, 1, 1.5 and 2 kgCOD/m3.day. The results identified coir filter was the best in four researched materials with removal COD and specific substract utilization rate can reach 98%, and 0.6 kg COD/kgVSS.day. Research results open the new prospects for the application of the cheap materials, available for wastewater treatment.

Gender differences in the Achilles tendon load during the fencing lunge

2014 ◽  
Vol 6 (3) ◽  
Author(s):  
Jonathan Kenneth Sinclair ◽  
Lindsay Bottoms
Keyword(s):  
Gender Differences ◽  
Achilles Tendon ◽  
Motion Capture ◽  
Tendon Injury ◽  
Force Platform ◽  
Motion Capture System ◽  
3D Motion ◽  
Loading Rates ◽  
Tendon Pathology ◽  
3D Motion Capture

AbstractRecent epidemiological analyses in fencing have shown that injuries and pain linked specifically to fencing training/competition were evident in 92.8% of fencers. Specifically the prevalence of Achilles tendon pathology has increased substantially in recent years, and males have been identified as being at greater risk of Achilles tendon injury compared to their female counterparts. This study aimed to examine gender differences in Achilles tendon loading during the fencing lunge.Achilles tendon load was obtained from eight male and eight female club level epee fencers using a 3D motion capture system and force platform information as they completed simulated lunges. Independent t-tests were performed on the data to determine whether differences existed.The results show that males were associated with significantly greater Achilles tendon loading rates in comparison to females.This suggests that male fencers may be at greater risk from Achilles tendon pathology as a function of fencing training/ competition.

Effect of Vial shaking on Loading Time of Epirubicin into Drug-Eluting Bead

2015 ◽  
Vol 5 (3) ◽  
Author(s):  
Kenji Ikeda ◽  
Yusuke Kawamura ◽  
Masahiro Kobayashi ◽  
Taito Fukushima ◽  
Yushi Sorin ◽  
...  
Keyword(s):  
Antitumor Agent ◽  
Loading Rates ◽  
Vortex Mixer ◽  
Long Time ◽  
Group A ◽  
Drug Eluting ◽  
Large Hepatocellular Carcinoma ◽  
Group B ◽  
Time Required ◽  
Short Time

Background: Although DC Bead has been useful in treatment of multiple and large hepatocellular carcinoma, loading time of doxorubicin into the DC Bead takes a long time of 30-120 minutes. Epirubicin is also used as an antitumor agent together with DC Bead, but its loading efficiency was not sufficiently elucidated. Methods: To shorten loading time of epirubicin into DC Bead (100-300µm, 300-500µm, 500-700µm), we examined the following three methods after mixing the drug: (a) let stand in room temperature, (b) agitated for 30 seconds with Vortex mixer, and (c) sonicated for 30 seconds with ultrasonic cleaner. After loading of epirubicin by each method, supernatant concentration for epirubicin was assayed at 5, 10, 30, 60, and 120 minutes. Results: Epirubicin loading rates for small bead (100-300µm) at 5 minutes were 82.9 % in group a, 93.8% in group b, and 79.9 % in group c. Similarly, medium bead (300-500µm), 40.1% in group a, 65.7% in group b and 45.5% in group c, respectively. In large-sized bead (500-700µm), loaded rates of epirubicin were 38.8% in group a, 59.0% in group b and 48.0% in group c. Agitation of mixture of epirubicin and DC Bead with Vortex mixer significantly shortened the loading time, but sonication did not affect the time required. Microscopic examination did not lead to any morphological change of microspheres in all the methods. Conclusions: Short time of agitation with Vortex mixer reduced the necessary time for loading of epirubicin in every standard of DC Bead.

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