scholarly journals Styrenic-Rubber Dielectric Elastomer Actuator with Inherent Stiffness Compensation

Actuators ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 44
Author(s):  
Giacomo Moretti ◽  
Luca Sarina ◽  
Lorenzo Agostini ◽  
Rocco Vertechy ◽  
Giovanni Berselli ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Design Procedure ◽  
Dielectric Elastomer ◽  
Side Length ◽  
Wide Spread ◽  
Mechanical Stiffness ◽  
Dielectric Elastomer Actuators ◽  
Mechanical Elements ◽  
First Time

Up to date, Dielectric Elastomer Actuators (DEA) have been mostly based on either silicone or acrylic elastomers, whereas the potential of DEAs based on inexpensive, wide-spread natural and synthetic rubbers has been scarcely investigated. In this paper, a DEA based on a styrene-based rubber is demonstrated for the first time. Using a Lozenge-Shaped DEA (LS-DEA) layout and following a design procedure previously proposed by the authors, we develop prototypes featuring nearly-zero mechanical stiffness, in spite of the large elastic modulus of styrenic rubber. Stiffness compensation is achieved by simply taking advantage of a biaxial pre-stretching of the rubber DE membrane, with no need for additional stiffness cancellation mechanical elements. In the paper, we present a characterization of the styrene rubber-based LS-DEA in different loading conditions (namely, isopotential, isometric, and isotonic), and we prove that actuation strokes of at least 18% the actuator side length can be achieved, thanks to the proposed stiffness-compensated design.

Fabrication and characterization of linear motion dielectric elastomer actuators

2006 ◽  
Author(s):  
Min Young Jung ◽  
Nguyen Huu Chuc ◽  
Jung Woo Kim ◽  
Ig Mo Koo ◽  
Kwang Mok Jung ◽  
...  
Keyword(s):  
Dielectric Elastomer ◽  
Linear Motion ◽  
Dielectric Elastomer Actuators ◽  
Fabrication And Characterization

Prevalence of Cryptosporidiosis in Ostriches from Central and South Parts of Iraq

2020 ◽  
Vol 44 (1) ◽  
pp. 63-67
Author(s):  
Al- Zubaidei H. Hamza
Keyword(s):  
Infection Rate ◽  
Morphological Characterization ◽  
Wide Spread ◽  
Traditional Methods ◽  
Fecal Samples ◽  
Cryptosporidium Spp ◽  
Significant Difference ◽  
June July ◽  
First Time

The prevalence of Ostriches cryptosporidiosis was determined for the first time in central and south parts of Iraq to study the effects of age, sex and months on the infection rate and to record the morphological characterization of Cryptosporidium spp in Ostriches. A total of 200 Ostriches fecal samples were examined by traditional methods for detection of the parasite. The total infection rate was 11% (22/200), and the highest infection rate was 12.26% (13/106) in chicks ( 9 months), while the lowest infection rate was 9.57% (9/94) recorded in the adult (> 9 Months). The study included seven provinces in the central and south parts of Iraq: Wasit, Baghdad, Babylon, Diyala, Karbala, Al-Najaf and Al-Qadisiyah. The highest infection rate was reported in Al-Najaf (23.53%) compared with the lowest rate (0%) in Wasit province. March reported an infection rate of 50%, while the lowest rate (0%) was registered during the summer months: June, July and August with a significant difference (P0.05) among months of the study. Morphologically, the study indicated the wide spread of Cryptosporidium parasites in Ostriches in both central and south area of Iraq

scholarly journals A Simple Dynamic Characterization Method for Thin Stacked Dielectric Elastomer Actuators by Suspending a Weight in Air and Electrical Excitation

Actuators ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 40
Author(s):  
Kentaro Takagi ◽  
Yuya Kitazaki ◽  
Kota Kondo
Keyword(s):  
Elastic Modulus ◽  
Forced Vibration ◽  
Electromechanical Coupling ◽  
Great Difficulty ◽  
Dielectric Elastomer ◽  
Local Deformation ◽  
Dynamic Elastic Modulus ◽  
Electrical Excitation ◽  
Dynamic Characterization ◽  
Dielectric Elastomer Actuators

This paper proposes a simple but effective method for characterizing dielectric elastomer actuators (DEAs), especially for thin stacked DEAs, which are promising for haptic devices but which measure the dynamic elastic modulus with great difficulty. The difficulty of the measurement of such a thin stacked DEA arises from the friction and local deformation of the surface between the DEA and a contact, as shown in this paper. In the proposed method, a DEA is vertically suspended and a weight is attached to it. The proposed method requires no contact with the surface of a DEA and uses only a weighting mass. Experimental results demonstrated the proposed method can estimate almost essential constants, such as the dynamic elastic modulus (Young’s modulus and damping time constant), the electrical constants (permittivity and resistivity), and the coefficient of electromechanical coupling, through the forced vibration induced by voltage actuation.

scholarly journals Chimera-competent eXtra-Embryonic eNdoderm (XEN) cells established from pig embryos

2020 ◽  
Author(s):  
Chi Park ◽  
Young Jeoung ◽  
Jun Uh ◽  
Kieun Park ◽  
Jessica Bridge ◽  
...  
Keyword(s):  
Stem Cells ◽  
Blastocyst Stage ◽  
Yolk Sac ◽  
Embryonic Cells ◽  
Wide Spread ◽  
Primitive Endoderm ◽  
Visceral Yolk Sac ◽  
First Time

AbstractIn this article, we report for the first time the derivation and characterization of extra-embryonic endoderm (XEN) cells from primitive endoderm (PrE) of porcine (p) embryos. The pXEN cells can be reliably and reproducibly generated from parthenote, in vitro and in vivo derived embryos. The pXEN cells retained all the hallmarks of PrE including expression of canonical PrE and XEN cell markers (GATA4, GATA6, SOX17, SALL4, FOXA2, and HNF4A). Transcriptome analysis further confirmed their XEN cell origin. The pXEN cells when introduced into blastocyst stage embryo contributed to wide-spread chimerism including visceral yolk sac, chorion, as well as embryonic gut and liver primordium in the fetus. The pXEN cells were shown to be an efficient nuclear donor for generating cloned offspring. Taken together, pXEN cells fulfil a longstanding need for a stable, chimera-competent, and nuclear transfer-compatible porcine embryonic cells with applications for agriculture and medicine.Significance StatementWe report for the first time, the derivation and characterization of extraembryonic endoderm (XEN) stem cells from porcine (p) embryos. The pXEN cells can be reliably and reproducibly derived from primitive endoderm precursors. When injected into blastocyst-stage embryos, the pXEN cells have contributed to wide-spread chimerism including visceral yolk sac, chorion of the extraembryonic membranes, as well as definitive endoderm of the fetus, primarily the embryonic gut and liver primordium. Additionally, these XEN cells have proven to be an efficient nuclear donor for generating cloned offspring. These newly discovered stem cells provide a novel model for studying lineage segregation, as well as a source for interspecies chimeras for generating endodermal organs, and for genome editing in livestock.

scholarly journals Monolithic Stacked Dielectric Elastomer Actuators

2021 ◽  
Vol 8 ◽  
Author(s):  
Jun Shintake ◽  
Daiki Ichige ◽  
Ryo Kanno ◽  
Toshiaki Nagai ◽  
Keita Shimizu
Keyword(s):  
Three Dimensional ◽  
Dielectric Elastomer ◽  
Free Form ◽  
Microfluidic Channels ◽  
Successful Implementation ◽  
Elastomeric Matrix ◽  
Dielectric Elastomer Actuators ◽  
Multiple Electrodes ◽  
Output Force

Dielectric elastomer actuators (DEAs) are a promising actuator technology for soft robotics. As a configuration of this technology, stacked DEAs afford a muscle-like contraction that is useful to build soft robotic systems. In stacked DEAs, dielectric and electrode layers are alternately stacked. Thus, often a dedicated setup with complicated processes or sometimes laborious manual stacking of the layers is required to fabricate stacked actuators. In this study, we propose a method to monolithically fabricate stacked DEAs without alternately stacking the dielectric and electrode layers. In this method, the actuators are fabricated mainly through two steps: 1) molding of an elastomeric matrix containing free-form microfluidic channels and 2) injection of a liquid conductive material that acts as an electrode. The feasibility of our method is investigated via the fabrication and characterization of simple monolithic DEAs with multiple electrodes (2, 4, and 10). The fabricated actuators are characterized in terms of actuation stroke, output force, and frequency response. In the actuators, polydimethylsiloxane (PDMS) and eutectic gallium–indium (EGaIn) are used for the elastomeric matrix and electrode material, respectively. Microfluidic channels are realized by dissolving a three-dimensional printed part suspended in the elastomeric structure. The experimental results show the successful implementation of the proposed method and the good agreement between the measured data and theoretical predication, validating the feasibility of the proposed method.

Sign in / Sign up

Export Citation Format

Share Document