Synchronized fractionation and phase separation in binary colloids

ABSTRACTThe structure of several classes of silica/siloxane molecular composites is investigated using small-angle x-ray and neutron scattering. These filled elastomers can be prepared through different synthethic protocols leading to a range of fillers including particulates with both rough and smooth surfaces, particulates with dispersed interfaces, and polymeric networks. We also find examples of bicontinuous filler phases that we attribute to phase separation via spinodal decomposition. In-situ kinetic studies of particulate fillers show that the precipitate does not develop by conventional nucleation-and-growth. We see no evidence of growth by ripening whereby large particles grow by consumption of small particles. Rather, there appears to be a limiting size set by the elastomer network itself. Phase separation develops by continuous nucleation of particles and subsequent growth to the limiting size. We also briefly report studies of polymer-toughened glasses. In this case, we find no obvious correlation between organic content and structure.

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Analysis of the Particles’ Movement Over the Flat and Profiled Rotating Discs surface in the Velocity Layer of the Viscous Gas

Siberian Journal of Physics ◽

10.54362/1818-7919-2011-6-2-17-23 ◽

2021 ◽

Vol 6 (2) ◽

pp. 17-23

Author(s):

Valeriy I. Pinakov ◽

Konstantin V. Kulik ◽

Boris E. Grinberg

Keyword(s):

Qualitative Difference ◽

Surface Region ◽

Vertex Angle ◽

Oscillation Regime ◽

Small Particles ◽

Magnus Force ◽

Near Surface ◽

Rotating Discs ◽

Large Particles ◽

Velocity Layer

Experiments on the rotating in the air cones with vertex angle β = 120º and flat disc shown that on frequencies Ω ≥ 2.5 hertz exists a qualitative difference in movement for the particles with diameters d ≈ 1 mm and d ≈ 0.1 mm. The particles with d ≈ 0.1 mm move in the near-surface region, the particles with d ≈ 1 mm jump up to 3 cm. Comparison of the spherical and aspheric (ellipsoid with axles d, d and 4 /3 d) particles' kinematics moving shown the inevitability of the large particles jump occurrence. Large particles come to self-oscillation regime by reason of periodically appearance of the Magnus force. Small particles are localized in the velocity layer

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Gravitational differentiation in the regimes from stokes settling to Rayleigh–Raylor flows

Физика земли ◽

10.31857/s0002-33372019215-30 ◽

2019 ◽

pp. 15-30

Author(s):

V. P. Trubitsyn

Keyword(s):

Viscous Fluid ◽

Interacting Particles ◽

Small Particles ◽

Continuous Transition ◽

New Approach ◽

Earth's Core ◽

The Core ◽

The Earth ◽

Large Particles ◽

Two Component

The Earth’s core was formed under gravitational differentiation in the course of the separation of iron and silicates. Most of the iron has gone into the core as early as when the Earth was growing. However, iron continued to precipitate even during the subsequent partial solidification which developed from the bottom upwards. At the different stages and in the different layers of the mantle, iron was deposited in different regimes. In this paper, the mechanisms of the deposition of a cloud of heavy interacting particles (or drops) in a viscous fluid are considered. A new approach suitable for analytical and numerical tracing the changes in the structure of the flows in a two-component suspension under continuous transition from the Stokessettling (for the case of a cloud of large particles) to the Rayleigh–Taylor flows and heavy diapirs (for the case of a cloud of small particles) is suggested. It is numerically and analytically shown that the both regimes are the different limiting cases of the sedimentation convection in suspensions.

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Flow and fouling in a pleated membrane filter

Journal of Fluid Mechanics ◽

10.1017/jfm.2016.194 ◽

2016 ◽

Vol 795 ◽

pp. 36-59 ◽

Cited By ~ 10

Author(s):

P. Sanaei ◽

G. W. Richardson ◽

T. Witelski ◽

L. J. Cummings

Keyword(s):

Membrane Fouling ◽

Membrane Filter ◽

Small Particles ◽

Porous Support ◽

Equal Area ◽

Membrane Filters ◽

Membrane Pores ◽

Dead End ◽

Large Particles ◽

Membrane Geometry

Pleated membrane filters are widely used in many applications, and offer significantly better surface area to volume ratios than equal-area unpleated membrane filters. However, their filtration characteristics are markedly inferior to those of equivalent unpleated membrane filters in dead-end filtration. While several hypotheses have been advanced for this, one possibility is that the flow field induced by the pleating leads to spatially non-uniform fouling of the filter, which in turn degrades performance. In this paper we investigate this hypothesis by developing a simplified model for the flow and fouling within a pleated membrane filter. Our model accounts for the pleated membrane geometry (which affects the flow), for porous support layers surrounding the membrane, and for two membrane fouling mechanisms: (i) adsorption of very small particles within membrane pores; and (ii) blocking of entire pores by large particles. We use asymptotic techniques based on the small pleat aspect ratio to solve the model, and we compare solutions to those for the closest-equivalent unpleated filter.

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Scattering Properties of Cometary Dust Based on Polarimetric Data

International Astronomical Union Colloquium ◽

10.1017/s0252921100066884 ◽

1991 ◽

Vol 126 ◽

pp. 249-252

Author(s):

Sonoyo Mukai ◽

Tadashi Mukai ◽

Sen Kikuchi

Keyword(s):

Linear Polarization ◽

Phase Function ◽

Mie Scattering ◽

Mixing Ratio ◽

Small Particles ◽

Cometary Dust ◽

Maximum Polarization ◽

Large Particles ◽

Lower Maximum ◽

Phase Angles

AbstractReferring to the dust model in Mukai and Mukai(1990), where the scattering by large rough particles and Mie scattering by small particles are taken into account, a phase function of linear polarization of several comets is examined, especially in a region of phase angles α near a maximum polarization. A lower maximum polarization observed in comet Austin(1989c1) than those in comets West(1975n) and P/Halley leads a speculation that a mixing ratio of rough scattering to Mie scattering in comet Austin increases from a sun-comet distance r of 0.6 AU to 1.2 AU. This implies that a shortage of large particles in comet Austin occured in r <1 AU.

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Bacillus mycoides phages and their satellites

Canadian Journal of Microbiology ◽

10.1139/m84-103 ◽

1984 ◽

Vol 30 (5) ◽

pp. 691-698 ◽

Cited By ~ 1

Author(s):

Anna S. Tikhonenko ◽

Nina N. Belyaeva ◽

Anna F. Kretova

Keyword(s):

Inner Core ◽

Structural Elements ◽

Small Particles ◽

Electron Microscopic ◽

Bacillus Mycoides ◽

Specific Antibodies ◽

Helper Phage ◽

Electron Microscopic Technique ◽

Large Particles ◽

The Relationship

The relationship between large and small particles of phages No. 1M and H17 reproducing simultaneously in one and the same bacterial cell of Bacillus mycoides was studied by the immune electron microscopic technique. The large particles of phages No. 1M and H17 were morphologically identical with phage No. 1 of B. mycoides, whereas only the tails of small particles of phages No. 1M and H17 were morphologically identical with the tail of phage No. 1. Antigens were identified in phages No. 1, No. 1M, and H17 using specific antibodies against phage No. 1, containing only large phage particles, and specific antibodies against phage H17 small heads. It was shown that (i) all structural elements of large particles and tails of small particles of phage No. 1M were antigenically identical with those of phage No. 1; (ii) all structural elements of small and large particles of phage H17, except the inner core of the tail, were antigenically different from phage No. 1; and (iii) the small heads of phages No. 1M and H17 were antigenically identical. Particles of phage No. 1 are morphologically and antigenically identical with the large particles of phage No. 1M and are antigenically different from the large particles of phage H17. Since the tails of small and large particles are antigenically identical in each phage pair (No. 1M and H17), this suggests that in both cases, the genome of a small defective phage codes for the synthesis of head proteins only, whereas its tail is borrowed from the corresponding helper phage. The small phage may therefore be considered as a satellite of the large phage which depends on a helper partner for production of complete particles and whose tail proteins are identical with those of the helper phage.

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Assessment of Scavenge Efficiency for a Helicopter Particle Separation System

Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Wind Turbine Technology ◽

10.1115/gt2011-45307 ◽

2011 ◽

Author(s):

Leiyong Jiang ◽

Michael Benner ◽

Jeff Bird

Keyword(s):

Shape Factor ◽

Flow Characteristics ◽

Particle Separation ◽

Operating Conditions ◽

Separation Mechanism ◽

Separation System ◽

Small Particles ◽

Inlet Velocity ◽

Separation Systems ◽

Large Particles

The effectiveness of a typical helicopter particle separation system has been numerically assessed at practical operating conditions and sand environments for various scenarios. The particle separation mechanism and its limitation are revealed by the flow characteristics and particle trajectories in the flow-field. The separation-by-inertia concept is effective for removing large particles, but problematic for small particles of diameter (d) ≤ 36μm. The particle size, shape factor, and rebound characteristics exert substantial effects on particle scavenge efficiency. On the other hand, the effects of gravity, particle inlet velocity, inlet mass distribution, and engine operating conditions on scavenge efficiency are minor or limited for the configurations and operating conditions considered in the present study. In addition, a few suggestions for further investigation on engine particle separation systems are included.

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LDV measurements of an air-solid two-phase flow in a vertical pipe

Journal of Fluid Mechanics ◽

10.1017/s0022112084000422 ◽

1984 ◽

Vol 139 ◽

pp. 417-434 ◽

Cited By ~ 406

Author(s):

Yutaka Tsuji ◽

Yoshinobu Morikawa ◽

Hiroshi Shiomi

Keyword(s):

Two Phase Flow ◽

Laser Doppler Velocimeter ◽

Medium Size ◽

Phase Flow ◽

Small Particles ◽

Vertical Pipe ◽

Two Phase ◽

Air Turbulence ◽

Large Particles ◽

Particle Velocities

Measurements of air and solid-particle velocities were made in a vertical pipe two-phase flow by the use of a laser-Doppler velocimeter (LDV). Five kinds of plastic particles, diameters of which ranged from about 3 mm to 200 μm, were transported in a vertical pipe of 30 mm inner diameter. It was found that, the smaller the particle size, the flatter was the mean air velocity distribution for the same mass flow ratio of solids to air. Large particles increased air turbulence throughout the pipe section, while small particles reduced it. Both effects of promotion and suppression of turbulence were observed at the same time in the presence of particles of medium size, that is, the turbulence was increased around the pipe centre and reduced near the wall. The frequency spectrum of air turbulence normalized by the turbulence intensity was not changed by the large particles. In the presence of the small particles, the higher-frequency parts of the spectrum increased.

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ZnS:Ag Luminescent Nanoparticles Synthesized with Different Molar Ratio of S/Zn

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.79-82.589 ◽

2009 ◽

Vol 79-82 ◽

pp. 589-592 ◽

Cited By ~ 3

Author(s):

Hua Qu ◽

Li Xin Cao ◽

Ge Su ◽

Wei Liu ◽

Yuan Guang Sun ◽

...

Keyword(s):

Blue Emission ◽

Molar Ratio ◽

Small Particles ◽

Sphalerite Structure ◽

Zns Nanoparticles ◽

Hydrothermal Preparation ◽

Hydrothermal Route ◽

Large Particles ◽

Luminescent Nanoparticles ◽

Defect Luminescence

ZnS:Ag (Ag+-doped ZnS) nanoparticles have been synthesized through the hydrothermal route, and the effects of the molar ratio of S/Zn in reagents have been studied. The products are all cubic sphalerite structure, and the crystallinity is generally increased as this ratio rises. The ratio less than 1 leads to small particles less than 10 nm, and the ratio more than 1 leads to large particles between 20~30 nm. Luminescence properties of samples show significant dependence on the ratio. The sample synthesized using stoichiometric reagents during hydrothermal preparation exhibits the strongest blue emission in this series. There is significant defect luminescence in samples synthesized using nonstoichiometric reagents and the Ag-related luminescence is quenched in them.

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Research on Networking of the Large Capacity Power Backbone Transmission Network Based on Cross Technology

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.385-386.1090 ◽

2013 ◽

Vol 385-386 ◽

pp. 1090-1094

Author(s):

Jun Hong Ni ◽

Shi Cong Song ◽

Zhen Dong Zhao

Keyword(s):

Future Development ◽

Theoretical Foundation ◽

New Technology ◽

Transmission Network ◽

Small Particles ◽

Key Technology ◽

Advantages And Disadvantages ◽

Large Particles ◽

High Bandwidth ◽

Hybrid Cross

The 12th Five-Year Plan requires the power backbone transmission network to be with large particles and high bandwidth. The new technology-OTN can meet the requests. In addition, OTN makes up for the limitation of small particles transmission of SDH and the defects of WDM networking. Cross is the key technology of OTN. OTN electrical, optical and photoelectrical hybrid cross techniques and their advantages and disadvantages are introduced in this paper. At last, three kinds of cross network strategies are put forward to meet the needs of the future development of Power backbone transmission network, which make the theoretical foundation for the construction of the net.

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