Acceleration of coagulation of particles in oil utilizing an a.c. electric field

2004 ◽  
Vol 218 (3) ◽  
pp. 317-326 ◽  
Author(s):  
H Yanada ◽  
N Nishimura ◽  
T Imagawa
Keyword(s):  
Electric Field ◽  
Double Layer ◽  
High Performance ◽  
Oscillation Amplitude ◽  
Small Diameter ◽  
Silica Particles ◽  
Insulating Liquids ◽  
Coagulation Of Particles ◽  
Electrostatic Filter ◽  
Spherical Silica Particles

This paper describes an experimental investigation of the coagulation of particles in oil accelerated by the action of an a.c. electric field. The ultimate goal of the investigation is to develop a high-performance electrostatic filter for insulating liquids. In order to reveal the coagulation mechanism and find out the mechanical conditions suitable for the coagulation, the effects of various factors on the coagulation are investigated using spherical silica particles of 2, 4 and 6 μm in diameter. The coagulating state of the silica particles in oil is observed using a video-microscope with a CCD (charge coupled device) camera under various conditions. It is shown that the coagulation is better promoted with larger particles and that the particles having a small diameter are not easily coagulated. It is also shown that the oscillation amplitude relative to the double-layer thickness dominates the coagulation phenomenon. The experimental results suggest that when the surface charge on a particle and the charge in the surrounding double layer are appropriately polarized by the influence of the a.c. electric field, the coagulation is accelerated by virtue of a (relatively) strong attractive force acting between two-particle-double-layer pairs.

scholarly journals Durability and Performance of Ferrocement Infill Wall Panel

2019 ◽  
Vol 5 (6) ◽  
pp. 1205-1213
Author(s):  
Muhammad Harunur Rashid ◽  
Zahangir Alam ◽  
Firoz Mahmud ◽  
M S Anita
Keyword(s):  
Double Layer ◽  
High Performance ◽  
Steel Wire ◽  
Small Diameter ◽  
Single Layer ◽  
Wire Mesh ◽  
Temperature Cycle ◽  
Infill Wall ◽  
Strength Performance ◽  
Layer Sample

Ferrocement is composed of cement mortar reinforced with small diameter closely spaced steel wire mesh to form a thin section conforming high performance of serviceability. The present study investigates the performance of ferrocement panels focused on the mechanical properties, water absorption and durability. A series of specimens were cast with single and double mesh layers. Flexural performance was carried out following sixty days in temperature cycle and in corrosion cell. These results was compared with the controlled sample. The test results shows that the flexural strength performance was reduced by 52% and 35% for single and double layer wire mesh samples respectively  followed by corrosion environment. First crack load also changed after completion of sixty temperature cycles. This load is 27.3%, 42.3% and 31.8% of failure load for controlled sample, sample in room air after every temperature cycle and samples in room air following quenching after every temperature cycle respectively for single mesh layer sample, and for double mesh layer sample these values are 38.9%, 30.1% and 17.7%. Early first crack is found for the samples following quenching and cooled in room air; however, both types of samples are in low absorption level. This data represents that double layer mesh specimen exhibits better when compared to single layer mesh specimen in strength and corrosion parameters.

Coagulation of particles in oil by an a.c. electric field (fundamental experiment)

1997 ◽  
Vol 211 (6) ◽  
pp. 451-461 ◽  
Author(s):  
H Yanada ◽  
R Okumura
Keyword(s):  
Electric Field ◽  
Velocity Gradient ◽  
Charge Coupled Device ◽  
Coagulation Process ◽  
Spherical Silica ◽  
Video Microscope ◽  
Coagulation Of Particles ◽  
Spherical Silica Particles ◽  
Mechanical Factors ◽  
Fundamental Experiment

This paper describes an experimental investigation of the coagulation of particles in oil under the action of an a.c. electric field. The investigation is carried out to acquire fundamental data to develop an electrostatic liquid filter with higher performance. The coagulation process of spherical silica particles is observed using a video-microscope with a CCD (charge coupled device) camera under various conditions and the effects of some mechanical factors such as the strength of the a.c. electric field, the velocity gradient of flow and so on are examined. The electric field is applied perpendicularly to the flow and particles are aligned in the same direction as the a.c. electric field by its action. The experiment shows that a certain frequency of a.c. electric field and a certain velocity gradient of flow exist which render the rate of coagulation maximum. It is pointed out that an interaction between the a.c. electric field and the flow field has a significant influence on the coagulation process.

scholarly journals Spherical Silica Particles with Double-layer Structures Containing Silver Halides in the Core.

2001 ◽  
pp. 299-306
Author(s):  
Minahiro OKABAYASHI ◽  
Zhi-Ping BAI ◽  
Hiroshi KATO ◽  
Shigeki OKAZAKI ◽  
Aiko HATTORI ◽  
...  
Keyword(s):  
Double Layer ◽  
Silica Particles ◽  
Silver Halides ◽  
The Core ◽  
Layer Structures ◽  
Spherical Silica ◽  
Spherical Silica Particles

Coagulation of particles in oil by an a.c. electric field (observation of the coagulation process under various mechanical conditions)

2001 ◽  
Vol 215 (2) ◽  
pp. 201-209 ◽  
Author(s):  
H Yanada ◽  
M Kikuchi ◽  
N Nishimura
Keyword(s):  
Electric Field ◽  
Velocity Gradient ◽  
Ccd Camera ◽  
Mean Amplitude ◽  
Charge Coupled Device ◽  
Coagulation Process ◽  
Video Microscope ◽  
Coagulation Of Particles ◽  
Spherical Silica Particles ◽  
A Charge

This paper describes an experimental investigation of the coagulation of particles in oil under the action of an a.c. electric field. The investigation is carried out to acquire fundamental data to develop an electrostatic liquid filter with higher performance. The coagulation process of spherical silica particles in oil is observed by tracking a certain particle arbitrarily chosen and using a video-microscope with a charge coupled device (CCD) camera under various mechanical conditions. The observations show that particles are coagulated by approaching one another, in particular, owing to the velocity gradient of flow and entering the region where attractive forces are exerted among them, and that the velocity gradient in the direction of the electric field is more effective for particles to be coagulated than that in the direction perpendicular to the electric field. The experiment shows that a certain frequency of the a.c. electric field at which the coagulation is most promoted exists, and that the frequency increases with increase in the strength of the a.c. electric field and the zeta potential of particles. The experimental results suggest that the mean amplitude of oscillation of particles in the direction of the a.c. electric field may dominate the degree of coagulation.

Prospects for convergent beam electron diffraction with a 200kV cold field-emission transmission electron microscope

1991 ◽  
Vol 49 ◽  
pp. 466-467
Author(s):  
J W Steeds ◽  
R Vincent
Keyword(s):  
Field Emission ◽  
High Performance ◽  
Small Diameter ◽  
Convergent Beam Electron Diffraction ◽  
Zone Axis ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Good Crystallinity ◽  
Special Modification ◽  
Convergent Beam

We review the analytical powers which will become more widely available as medium voltage (200-300kV) TEMs with facilities for CBED on a nanometre scale come onto the market. Of course, high performance cold field emission STEMs have now been in operation for about twenty years, but it is only in relatively few laboratories that special modification has permitted the performance of CBED experiments. Most notable amongst these pioneering projects is the work in Arizona by Cowley and Spence and, more recently, that in Cambridge by Rodenburg and McMullan.There are a large number of potential advantages of a high intensity, small diameter, focussed probe. We discuss first the advantages for probes larger than the projected unit cell of the crystal under investigation. In this situation we are able to perform CBED on local regions of good crystallinity. Zone axis patterns often contain information which is very sensitive to thickness changes as small as 5nm. In conventional CBED, with a lOnm source, it is very likely that the information will be degraded by thickness averaging within the illuminated area.

Modeling the Electrical Double Layer to Understand the Reaction Environment in a CO2 Electrocatalytic System

2019 ◽  
Author(s):  
Divya Bohra ◽  
Jehanzeb Chaudhry ◽  
Thomas Burdyny ◽  
Evgeny Pidko ◽  
wilson smith
Keyword(s):  
Electric Field ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Surface Reaction ◽  
Catalyst Surface ◽  
Local Reaction ◽  
Reaction Diffusion ◽  
Alkali Metal Cations ◽  
Applied Potential ◽  
Critical Aspect

<p>The environment of a CO<sub>2</sub> electroreduction (CO<sub>2</sub>ER) catalyst is intimately coupled with the surface reaction energetics and is therefore a critical aspect of the overall system performance. The immediate reaction environment of the electrocatalyst constitutes the electrical double layer (EDL) which extends a few nanometers into the electrolyte and screens the surface charge density. In this study, we resolve the species concentrations and potential profiles in the EDL of a CO<sub>2</sub>ER system by self-consistently solving the migration, diffusion and reaction phenomena using the generalized modified Poisson-Nernst-Planck (GMPNP) equations which include the effect of volume exclusion due to the solvated size of solution species. We demonstrate that the concentration of solvated cations builds at the outer Helmholtz plane (OHP) with increasing applied potential until the steric limit is reached. The formation of the EDL is expected to have important consequences for the transport of the CO<sub>2</sub> molecule to the catalyst surface. The electric field in the EDL diminishes the pH in the first 5 nm from the OHP, with an accumulation of protons and a concomitant depletion of hydroxide ions. This is a considerable departure from the results obtained using reaction-diffusion models where migration is ignored. Finally, we use the GMPNP model to compare the nature of the EDL for different alkali metal cations to show the effect of solvated size and polarization of water on the resultant electric field. Our results establish the significance of the EDL and electrostatic forces in defining the local reaction environment of CO<sub>2</sub> electrocatalysts.</p>

Photodiodes based on MAPbBr3/Bi3+ doped MAPbCl3 single crystals heterojunction for X-ray detection

CrystEngComm ◽  
2021 ◽  
Author(s):  
Yuzhu Pan ◽  
Xin Wang ◽  
Jingda Zhao ◽  
Yubing Xu ◽  
Yuwei Li ◽  
...  
Keyword(s):  
Electric Field ◽  
Single Crystals ◽  
External Electric Field ◽  
High Performance ◽  
X Ray

Perovskites single crystals (PSCs) could be used to made high performance photoelectric detectors due to its superior optoelectronic characteristics. Generally, external electric field need to be applied in the PSCs-based...

scholarly journals Magnetic properties of (Bi1−xLax)(Fe,Co)O3 films fabricated by a pulsed DC reactive sputtering and demonstration of magnetization reversal by electric field

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Munusamy Kuppan ◽  
Daichi Yamamoto ◽  
Genta Egawa ◽  
Sivaperuman Kalainathan ◽  
Satoru Yoshimura
Keyword(s):  
Electric Field ◽  
Magnetization Reversal ◽  
High Performance ◽  
Magnetic Domain ◽  
Magnetic Film ◽  
Film Plane ◽  
Force Microscopy ◽  
Domain Structures ◽  
Pulsed Dc ◽  
Submicron Scale

Abstract(Bi1−xLax)(Fe,Co)O3 multiferroic magnetic film were fabricated using pulsed DC (direct current) sputtering technique and demonstrated magnetization reversal by applied electric field. The fabricated (Bi0.41La0.59)(Fe0.75Co0.25)O3 films exhibited hysteresis curves of both ferromagnetic and ferroelectric behavior. The saturated magnetization (Ms) of the multiferroic film was about 70 emu/cm3. The squareness (S) (= remanent magnetization (Mr)/Ms) and coercivity (Hc) of perpendicular to film plane are 0.64 and 4.2 kOe which are larger compared with films in parallel to film plane of 0.5 and 2.5 kOe. The electric and magnetic domain structures of the (Bi0.41La0.59)(Fe0.75Co0.25)O3 film analyzed by electric force microscopy (EFM) and magnetic force microscopy (MFM) were clearly induced with submicron scale by applying a local electric field. This magnetization reversal indicates the future realization of high performance magnetic device with low power consumption.

scholarly journals Design, synthesis, and catalytic performance of modified graphene oxide based on a cobalt complex as a heterogenous catalyst for the preparation of aminonaphthoquinone derivatives

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17108-17115
Author(s):  
Mahnaz Mirheidari ◽  
Javad Safaei-Ghomi
Keyword(s):  
Graphene Oxide ◽  
Cobalt Complex ◽  
Catalytic Performance ◽  
Silica Particles ◽  
Design Synthesis ◽  
Spherical Silica ◽  
Modified Graphene Oxide ◽  
Spherical Silica Particles ◽  
Heterogenous Catalyst ◽  
Modified Graphene

GO@f-SiO2@Co is a heterogenous catalyst composed of spherical silica particles grafted on the surface of graphene oxide with ethylenediamine ligands and coordination with Co(ii). We assessed the activity of the catalyst for the synthesis of aminonaphthoquinones.

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