A Piezoelectric Micropumping Device

2009 ◽  
Author(s):  
M. Yakut Ali ◽  
Cuifang Kuang ◽  
Jamil Khan ◽  
Guiren Wang
Keyword(s):  
Liquid Water ◽  
Acoustic Streaming ◽  
Check Valve ◽  
Pressure Head ◽  
Noise Generation ◽  
Local Velocity ◽  
Electrical Field ◽  
Quantitative Results ◽  
Applied Electrical Field ◽  
Lower Noise

A dynamic micropumping device has been developed, which is based on acoustic streaming generated by a piezoelectric microtransducer actuated in d31 mode without any check valve. Piezoelectric microtransducers immersed in liquid (water) are used as actuators due to some of their unique properties such as lower noise generation and ease of miniaturization. Quantitative results of maximum local velocity are presented for different tip configuration of the same actuator for comparison. In addition, this work also demonstrates the quantitative measures of the pumping performance such as the pressure head generated as a function of different relevant parameters such as applied electrical field, AC frequency and length of the actuator.

scholarly journals Preparation of Fe3O4-Ag Nanocomposites with Silver Petals for SERS Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1288
Author(s):  
Thi Thuy Nguyen ◽  
Fayna Mammeri ◽  
Souad Ammar ◽  
Thi Bich Ngoc Nguyen ◽  
Trong Nghia Nguyen ◽  
...  
Keyword(s):  
Self Assembly ◽  
Hot Spots ◽  
Surface Enhanced Raman Spectroscopy ◽  
Electrical Field ◽  
Stabilizing Agents ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sers Sensing ◽  
Applied Electrical Field ◽  
Positively Charged

The formation of silver nanopetal-Fe3O4 poly-nanocrystals assemblies and the use of the resulting hetero-nanostructures as active substrates for Surface Enhanced Raman Spectroscopy (SERS) application are here reported. In practice, about 180 nm sized polyol-made Fe3O4 spheres, constituted by 10 nm sized crystals, were functionalized by (3-aminopropyl)triethoxysilane (APTES) to become positively charged, which can then electrostatically interact with negatively charged silver seeds. Silver petals were formed by seed-mediated growth in presence of Ag+ cations and self-assembly, using L-ascorbic acid (L-AA) and polyvinyl pyrrolidone (PVP) as mid-reducing and stabilizing agents, respectively. The resulting plasmonic structure provides a rough surface with plenty of hot spots able to locally enhance significantly any applied electrical field. Additionally, they exhibited a high enough saturation magnetization with Ms = 9.7 emu g−1 to be reversibly collected by an external magnetic field, which shortened the detection time. The plasmonic property makes the engineered Fe3O4-Ag architectures particularly valuable for magnetically assisted ultra-sensitive SERS sensing. This was unambiguously established through the successful detection, in water, of traces, (down to 10−10 M) of Rhodamine 6G (R6G), at room temperature.

Spinal neurite reabsorption and regrowth in vitro depend on the polarity of an applied electric field

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 31-41
Author(s):  
C.D. McCaig
Keyword(s):  
Electric Field ◽  
Neural Tube ◽  
Applied Field ◽  
Growth Cones ◽  
Individual Growth ◽  
Electrical Field ◽  
Field Reversal ◽  
Specific Change ◽  
Applied Electrical Field

Retraction and regrowth of frog neural tube neurites have been studied in vitro in control cultures and in the presence of a small, continuously applied electrical field. In control cultures, some degree of retraction was seen in 39% of neurites while 7% were reabsorbed completely. Reabsorption of anodal-facing neurites was at least twice as common, with 67% showing some retraction and 17% almost totally reabsorbed. Cathodal-facing neurites were spared from retraction. Following extreme reabsorption of anodal-facing neurites, reversal of the electric field promoted regeneration in 47% (9/19) of cases studied. growth cone morphology also was determined by the polarity of the applied field. Anodal-facing growth cones had fewer filopodia than cathodal-facing growth cones sharing the same cell body. Field reversal induced a polarity-specific change in filopodia number on individual growth cones: a shift from anodal to cathodal increased filopodia numbers and vice versa. Some possible mechanisms involved and the significance of these results are discussed.

scholarly journals Understanding Collaborative Effects between the Polymer Gel Structure and the Applied Electrical Field in Gel Electrophoresis Separation

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Jennifer A. Pascal ◽  
Koteswara Rao Medidhi ◽  
Mario A. Oyanader ◽  
Holly A. Stretz ◽  
Pedro E. Arce
Keyword(s):  
Gel Electrophoresis ◽  
Chemical Properties ◽  
Polymer Gels ◽  
Optimal Time ◽  
Polymer Gel ◽  
Gel Structure ◽  
Electrical Field ◽  
Standard Case ◽  
Similar Chemical ◽  
Applied Electrical Field

The collaborative effects between an applied orthogonal electrical field and the internal structure of polymer gels in gel electrophoresis is studied by using microscopic-based electrophoretic transport models that then are upscaled via the format of electro kinetics-hydrodynamics (EKHD). The interplay of the electrical field and internal gel morphology could impact the separation of biomolecules that, because of similar chemical properties, are usually difficult to separate. In this study, we focus on an irregular pore geometry of the polymer-gel structure by using an axially varying pore (i.e., an axially divergent section) and an orthogonal (to the main flow of solutes) applied electrical field. The microscopic-based conservation of species equation is formulated for the standard case of electrophoresis of charged particles within a geometrical domain, i.e., a pore, and upscaled to obtain macroscopic-based diffusion and mobility coefficients. These coefficients are then used in the calculation of the optimal time of separation to study the effect of the varying parameters of the pore structure under different values of the electrical field. The results are qualitatively consistent with those reported, in the literature, by using computational-based approaches as well as with experiments also reported in the literature, previously. The study shows the important collaborative effects between the applied electrical field and the internal geometry of the polymer gels that could lead to improving biomolecule separation in gel electrophoresis.

Transmitter exocytosis in cultured cerebellar granule cells stimulated with an applied electrical field

1996 ◽  
Vol 24 (3) ◽  
pp. 430S-430S ◽  
Author(s):  
Michael A. Cousin ◽  
Helen Hurst ◽  
Brigitte Held ◽  
David G. Nicholls
Keyword(s):  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Electrical Field ◽  
Cerebellar Granule ◽  
Applied Electrical Field

Pore-Spanning PPy(DBS) as a Voltage-Gated Synthetic Membrane Ion Channel

2016 ◽  
Author(s):  
Travis M. Hery ◽  
Vishnu-Baba Sundaresan
Keyword(s):  
Ion Transport ◽  
Reaction Rates ◽  
Transport Rate ◽  
Electrical Field ◽  
A Cell ◽  
The Given ◽  
First Time ◽  
Protein Reaction ◽  
Applied Electrical Field ◽  
Reduced State

The transport of monovalent cations across a suspended PPy(DBS) polymer membrane in an aqueous solution as a function of its redox state is investigated. Maximum ion transport is found to occur when PPy(DBS) is in the reduced state, and minimum transport in the oxidized state. No deviation in the dynamics of ion transport based on the direction of the applied electrical field is observed. Additionally, it is found that ion transport rates linearly increased proportional to the state of reduction until a steady state is reached when the polymer is fully reduced. Therefore controlled, bidirectional ion transport is for the first time demonstrated. The effect of aqueous Li+ concentration on ion transport in the fully reduced state of the polymer is studied. It is found that ion transport concentration dependence follows Michaelis-Menten kinetics (which models protein reaction rates, such as those forming ion channels in a cell membrane) with an r2 value of 0.99. For the given PPy(DBS) polymer charge density and applied potential across the membrane, the maximum possible ion transport rate per channel is found to be 738 ions per second and the Michaelis constant, representing the concentration at which half the maximum ion transport rate occurs, is 619.5mM.

Reduction of Noise at the Design Stage: A Case Study of a Lightly Loaded Assembly

1969 ◽  
Vol 184 (1) ◽  
pp. 593-614 ◽  
Author(s):  
M. A. Satter ◽  
B. Downs ◽  
G. R. Wray
Keyword(s):  
Analytical Study ◽  
Design Stage ◽  
Acoustic Absorption ◽  
Noise Generation ◽  
Noise Emission ◽  
Design Changes ◽  
Damping Materials ◽  
Lower Noise ◽  
Made In

An experimental and analytical study is made of the noise emission from the drawroll assembly of a textile draw-twisting machine. As an alternative to resorting to acoustic absorption techniques or the use of expensive high damping materials, investigations are made into the basic method of noise generation in the assembly. This leads to the incorporation of small design changes and the significantly lower noise emission thereby achieved is compared with the original emission. Aimed at the machine designer, the presentation is made in a straightforward, non-mathematical fashion.

Basic Performance Evaluation of Electro-Adhesive Film with Micro Mesh Sheet

2012 ◽  
Vol 516 ◽  
pp. 222-227
Author(s):  
Takao Kubo ◽  
Yasuhiro Kakinuma
Keyword(s):  
Smart Materials ◽  
Open Space ◽  
Smart Material ◽  
Adhesive Properties ◽  
Electrical Field ◽  
Adhesive Film ◽  
Number Of Layers ◽  
Basic Performance ◽  
Adhesive Effect ◽  
Applied Electrical Field

Smart materials have been developed in many leading technologies. Smart material is a material that gives a specific reaction to the change and stimulus of the external environment such as light, heat and electromagnetic fields. Electro-rheological Gel (ERG) is one smart material. ERG changes its surface adhesive properties rapidly according to the intensity of the applied electrical field. This unique property is named Electro-adhesive effect (EA effect). In this research, as a novel electro-adhesive film which is replaced with ERG, Electro-adhesive film with micro mesh sheets is developed and named EAMS. Furthermore, it is proved that the developed film using the mesh sheet produces the EA effect and that the performance of EAMS is enhanced according to the increase of the open space and the number of layers.

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