scholarly journals The Electric Honeycomb; an investigation of the Rose window instability

2017 ◽  
Vol 4 (10) ◽  
pp. 170503 ◽  
Author(s):  
Muhammad Shaheer Niazi
Keyword(s):  
Electric Field ◽  
Thermal Imaging ◽  
Driving Force ◽  
Critical Voltage ◽  
Charged Surface ◽  
Surface Distribution ◽  
Point Electrode ◽  
Electric Pressure ◽  
The Rose ◽  
Charged Ions

The Rose window instability is a little-explored electrohydrodynamic instability that manifests when a layer of low-conducting oil is placed in an electric field generated by corona discharge in a point-to-plane configuration. Above a critical voltage, the instability starts as a single dimple in the oil layer right below the point electrode and subsequently evolves into a characteristic pattern of polygonal cells. In this study, we experimentally explore governing parameters that guide the instability and document geometric attributes of the characteristic cellular pattern. The driving force for the instability has been attributed to the buildup of charged ions which in turn apply an electric pressure on the oil surface. We confirm the charged surface distribution using thermal imaging and demonstrate that the instability can be locally inhibited by preventing charge buildup under an ion shadow.

scholarly journals Electrostatic Analyses for a System Constituted by an Insulating Disk Whose One Plane Surface is Charged and Which is Backed by a Concentric Earthed Metal Disk Smaller Than the Insulating Disk Itself and an Earthed Sphere Approaching the Charged Surface of the Insulating Disk, and Its Application to the Case of a Typical Oxygen Regulator

2019 ◽  
Author(s):  
Nirmalya Basu
Keyword(s):  
Electric Field ◽  
Plane Surface ◽  
Dust Particles ◽  
Charged Dust ◽  
Potential Candidate ◽  
Charged Surface ◽  
Electrostatic Discharges ◽  
Valve Stem ◽  
Metal Disk ◽  
Metal Diaphragm

There is a proposition that the possible occurrence of electrostatic discharges inside an oxygen regulator between charged insulating components, such as diaphragms, and earthed metal components, such as the valve stem, could be a potential candidate responsible for oxygen regulator fires. In this paper, the electric field which might be produced at the tip of the valve stem due to charge produced on the diaphragm of a typical oxygen regulator by deposition of charged dust particles or by their impact on the diaphragm or both has been evaluated. The diaphragm, in many cases, is backed partially by a concentric earthed metal disk. The diaphragm has been modelled as an insulating disk. The tip of the valve stem has been modelled as an earthed sphere which is very small compared to the insulating disk and the backing earthed metal disk. An analytical expression for the electric field produced at the point of the sphere nearest to the charged surface of the insulator has been derived. Our expression takes into account not only the effect of the charge on the insulating disk, but also that due to the presence of the backing earthed metal disk. Results for the magnitude of this electric field have been computed for the case of a sample oxygen regulator. An expression for the critical charge density on the surface of the insulating disk has been derived, and its value has been obtained for the case of our sample oxygen regulator. The electric field inside the non-metal diaphragm has also been evaluated. It appears from our analyses that there is a possibility that an electrostatic discharge might occur inside an oxygen regulator, and with an enriched-oxygen atmosphere being present there, such a discharge could also lead to a fire incident.

scholarly journals A Novel Capacitive Sensing Principle for Microdevices

2015 ◽  
Author(s):  
Jian Zhou ◽  
Ronald N. Miles ◽  
Shahrzad Towfighian
Keyword(s):  
Electric Field ◽  
Driving Force ◽  
Design Principle ◽  
Electrostatic Force ◽  
Low Cost ◽  
Repulsive Force ◽  
Attractive Force ◽  
Sensor Design ◽  
Capacitive Sensing

Conventional capacitive sensing places significant limitations on the sensor design due to the pull-in instability caused by the electrostatic force. The main purpose of this study is to examine a low-cost novel capacitive sensing principle based on electrostatic balance which promises to avoid these design limitations. The approach uses an asymmetric electric field on a structure with fingers that can generate a repulsive force while the gap is low and create an attractive force while the gap is large. The size and thickness of the fingers are also responsible for creating repulsive or attractive forces on the structure. This approach has recently been applied successfully in the design of capacitive actuators to provide a repulsive driving force. A new design principle for capacitive sensing is described that avoids pull-in instability by designing the fingers such that the structure is at the equilibrium.

scholarly journals Study of Chromium Removal by the Electrodialysis of Tannery and Metal-Finishing Effluents

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Ruan C. A. Moura ◽  
Daniel A. Bertuol ◽  
Carlos A. Ferreira ◽  
Franco D. R. Amado
Keyword(s):  
Wastewater Treatment ◽  
Ion Exchange ◽  
Electric Field ◽  
Driving Force ◽  
Membrane Separation ◽  
Physicochemical Process ◽  
Separation Technique ◽  
Chromium Removal ◽  
Metal Finishing ◽  
Interesting Alternative

The metal-finishing and tannery industries have been under strong pressure to replace their current wastewater treatment based on a physicochemical process. The electrodialysis process is becoming an interesting alternative for wastewater treatment. Electrodialysis is a membrane separation technique, in which ions are transported from one solution to another through ion-exchange membranes, using an electric field as the driving force. Blends of polystyrene and polyaniline were obtained in order to produce membranes for electrodialysis. The produced membranes were applied in the recovery of baths from the metal-finishing and tannery industries. The parameter for electrodialysis evaluation was the percentage of chromium extraction. The results obtained using these membranes were compared to those obtained with the commercial membrane Nafion 450.

The Electric Field Analysis of the Structure of New Micro-Machined Gyroscope

2010 ◽  
Vol 43 ◽  
pp. 546-550
Author(s):  
Kang Huang ◽  
Gen Qian ◽  
Qing Song Liang ◽  
Yu Feng Qu
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Driving Force ◽  
Electric Field Distribution ◽  
Field Analysis ◽  
Finite Model ◽  
Detection Error ◽  
New Type ◽  
Electric Field Analysis ◽  
Processing Difficulty

The structure of current micro-machined gyroscope result in detection error and processing difficulty, which can be reduced by redesigning the structure such as a new type researched here to enhance the accuracy..The new structure for gyroscope and the method of driving force calculating for it is introduced in this paper. A 3D micro-machined gyroscope model has been built through CAD software, while finite model through CAE software. Besides, the driving structure has been analyzed to gain the size of driving force and electric-field distribution.

Fluid Mixing Control Inside a Y-Shaped Microchannel by Using Electrokinetic Instability

2007 ◽  
Author(s):  
Zheyan Jin ◽  
Hui Hu
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Fluid Mixing ◽  
Critical Voltage ◽  
Mixing Efficiency ◽  
Mixing Process ◽  
Static Electric Field ◽  
Electrokinetic Instability ◽  
Mixing Control ◽  
Static Electric Fields

An experimental study was conducted to further our understanding about the fundamental physics of electrokinetic instability (EKI) and to explore the effectiveness to enhance fluid mixing inside a Y-shaped microchannel by manipulating convective EKI waves. The dependence of the critical voltage of applied static electric field to trig EKI to generate convective EKI waves on the conductivity ratio of the two adjacent streams was quantified at first. The effect of the strength of the applied static electric field on the evolution of the convective EKI waves and fluid mixing process were assessed in terms of scalar concentration fields, shedding frequency of the convective EKI waves and scalar mixing efficiency. The effectiveness of manipulating the convective EKI waves by introducing alternative electric perturbations to the applied static electric fields was also explored for the further enhancement of the fluid mixing process inside the Y-shaped microchannel.

Boosting photocatalytic water splitting by tuning built-in electric field at phase junction

2019 ◽  
Vol 7 (17) ◽  
pp. 10264-10272 ◽  
Author(s):  
Jing Zhang ◽  
Xuebing Chen ◽  
Yu Bai ◽  
Chun Li ◽  
Ying Gao ◽  
...  
Keyword(s):  
Electric Field ◽  
Water Splitting ◽  
Charge Separation ◽  
Driving Force ◽  
Photocatalytic Water Splitting ◽  
Spatial Charge

Constructing a built-in electric field at the interface of semiconductors has been demonstrated to provide the driving force for spatial charge separation in photocatalysis.

Deformation of metallic liquid drop by electric field for contacts in molecular–organic electronics

2009 ◽  
Vol 465 (2106) ◽  
pp. 1799-1808 ◽  
Author(s):  
M. Bag ◽  
D. Gupta ◽  
N. Arun ◽  
K.S. Narayan
Keyword(s):  
Solid State ◽  
Surface Energy ◽  
Electric Field ◽  
Linear Response ◽  
Liquid Drop ◽  
Electrostatic Energy ◽  
Critical Voltage ◽  
Metallic Liquid ◽  
Linear Response Regime ◽  
Polymer Electronics

We study and use the behaviour of a metallic liquid drop in the presence of an external electric field (EF). The droplet profile is governed by the stabilizing surface energy and the destabilizing electrostatic energy, with a critical voltage beyond which the droplet becomes unstable. We explore the EF-induced behaviour of low melting temperature alloy in the liquid state and observe that the droplet modifications in the linear response regime can be retained upon cooling the drop to the solid state. We demonstrate that this procedure can be used as an electrode with precise dimensions for applications in molecular and polymer electronics.

Growth of Calcium Phosphate on Poled Piezoelectric Poly-L-lactic Acid Membrane by a Biomimetic Method

2007 ◽  
Vol 330-332 ◽  
pp. 703-706
Author(s):  
Chun Peng Huang ◽  
Dong Hua Guan ◽  
Kun Tian ◽  
Xin Min Chen ◽  
Lin Niu ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Electric Field ◽  
Photoelectron Spectroscopy ◽  
Charged Surface ◽  
X Ray ◽  
Charged Surfaces ◽  
Before And After ◽  
Dc Electric Field ◽  
Biomimetic Method

The bioactivity of poled piezoelectric PLLA membrane was investigated by studying the calcium phosphate formation in vitro using a biomimetic method. Samples (φ10mm) were poled under DC electric field of 8~l0kV/cm at 70°C for 30 min followed by cooling under the electric field. Surface chemistry of the samples before and after poling treatment was studied by X-ray photoelectron spectroscopy (XPS). Poled/unpoled samples were immersed in supersaturated calcification solution (SCS) for periods up to 24 h (36.5°C). The surface morphology and composition of the soaked samples were evaluated by using scanning electron microscope (SEM) and X-ray diffraction analysis (XRD). Poled samples showed two different charged surfaces, negatively-charged surface (N-PLLA) and positively-charged surface (P-PLLA). On the N-PLLA surfaces, SEM together with XRD showed a gradually formed calcium phosphate (Ca-P), while no obvious Ca-P on either P-PLLA or unpoled samples was observed. This study demonstrated that poled piezoelectric PLLA substrates induce substantially higher level of Ca-P formation than electrically neutral substrates and only N-PLLA, however, can improve Ca-P formation after immersion in SCS.

Ion trajectories in weak electrolytes

1980 ◽  
Vol 371 (1746) ◽  
pp. 413-427 ◽  
Keyword(s):  
Steady State ◽  
Electric Field ◽  
Applied Electric Field ◽  
Numerical Quadrature ◽  
Average Flow ◽  
Recombination Processes ◽  
Weak Electrolytes ◽  
The Mean ◽  
Charged Ions ◽  
Oppositely Charged

The equations of the mean relative trajectories of neighbouring oppositely charged ions in a weak electrolyte that has attained a steady state in a uniform applied electric field are determined analytically. Both the dissociation and recombination of ions are considered and the mean relative trajectories are defined in terms of the ensemble average flow patterns of the ions participating in these processes. For recombination of ions, the equation of the boundary of ionic attraction is also derived. The mean times involved in the dissociation and recombination processes are determined by using numerical quadrature. The results obtained are consistent with the Bjerrum (1926) theory of weak electrolytes.

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