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Rheological Behavior and Microstructure Characteristics of ...

2.1. Materials. In this study, P·II 42.5 cement is used as binding material; fly ash (FA), silica fume (SF), and metakaolin (MK) are used as SCMs, their particle size distributions and chemical constituents are measured by laser particle size analyzer and X-ray fluorescence spectrometer, respectively, as shown in Figure 1 and Table 1, respectively.. Natural river sand with fineness modulus of ...

Colloidal sedimentation (and filtration) - ScienceDirect

This qualitatively explains the reduction in the sedimentation velocity U which for dilute dispersions of uncharged, colloidal hard spheres (volume fraction 9<0.05) has the form (1) Colloidal sedimentation (and filtration) Philipse 201 where Vo is the (Stokes) sedimentation velocity of a free sphere and K …

Silica Nano Nanoparticles Powder - Buy Silica ...

Introduction: Nano-silicon dioxide (nano silica) is an inorganic chemical material, commonly known as silica. Because of its ultra-fine nanometer scale and size ranging from 1 to 100 nm, it has many unique properties, such as anti-ultraviolet optical properties, which can improve the anti-aging, strength and chemical resistance of other materials.

The transient settling of stable and ... - Cambridge Core

An experimental investigation of the sedimentation of monodisperse colloidal silica spheres with grafted octadecyl chains with three different interaction potentials is presented. Small particles (0.27 μm) behaved as hard spheres in cyclohexane, but larger ones (0.60 and 0.94 μm) are weakly flocculated by van der Waals attractions.

Rheological Behavior and Microstructure Characteristics of ...

This study explores the effects of metakaolin (MK) and silica fume (SF) on rheological behaviors and microstructure of self-compacting concrete (SCC). The rheology, slump flow, V-funnel, segregation degree (SA), and compressive strength of SCC are investigated. Microstructure characteristics, including hydration product and pore structure, are also studied.

Microstructure of high-temperature (>73 °C) siliceous ...

Marked birefringence of silica deposited on surfaces that evaporate to dryness is probably a strain effect. Repeated wetting and evaporation, often to dryness, and capillary effects control the deposition, morphology, and microstructure of most high-temperature sinter outside of the fully subaqueous zone.

Effect of Interparticle Interactions on Agglomeration and ...

The sedimentation half-times ts of initially monodisperse dispersions of 750, 505, and 350 nm silica microspheres were measured in water, in ethanol, and in aqueous NaBr solutions of concentration cNaBr ranging from 50 to 1000 mM, where the particles may have formed clusters. In water and in ethanol, ts was about 8, 18, and 33 h for the 750, 505, and 350 nm particles, respectively.

Microstructure investigations of Kamchatka geyserites ...

Oct 18, 2008· This paper discusses the results of examining solid geyserite specimens from two present-day Kamchatkan hydrothermal systems: from geysers of the Academy of Sciences and from the Eastern Thermal Field in the caldera of the Uzon Volcano. These studies were performed using methods of IR spectroscopy, XR spectral analysis, and electron microscopy. Three types of geysers were …

Biogenicity of silica precipitation around geysers and hot ...

However, late silica precipitation produced thick external encrustations of amorphous silica around many sheaths. Although boiling and very hot (more than 90 degrees C) waters were discharged, temperatures at many sites surrounding the vents remained sufficiently low and moist to support a microbial community that included thermophilic bacteria ...

The rheology and microstructure of an aging ...

Colloidal gels exhibit time-dependent bulk properties. However, the processes and mechanisms by which aging occurs are poorly understood, which complicates the prediction of macroscopic behavior in these systems. Using a model, thermoreversible, adhesive hard sphere system consisting of octadecyl-coated silica nanoparticles dispersed in tetradecane, rheological aging is quantitatively related ...

Aligned microstructure of some particulate polymer ...

Aligned microstructure of some particulate polymer composites obtained with an electric field C.PARK,R.E.ROBERTSON* Macromolecular Science and Engineering Center and Department of Materials Science and Engineering, The University of Michigan, Ann …

Particle dispersion in silica-poly(vinyl alcohol) coatings ...

Full Article. Particle Dispersion in Silica-Poly(vinyl alcohol) Coatings: Role of Particle-Polymer Interaction. Sunhyung Kim, £ Sang Hoon Sung, Sanghyuk Lim, and Kyung Hyun Ahn* Silica nanoparticle (SiNP)-poly(vinyl alcohol) (PVOH) coating is an important material system in paper coating applications, where particle distribution critically affects coating performance.

(123b) Interfacial Colloidal Sedimentation Equilibrium ...

In contrast to most previous sedimentation equilibrium studies, the present work focuses on relatively compact microstructures over 10-100 particle diameters due to the similarity of particle dimensions and the characteristic gravitational lengthscale (mgd/kT°Ö1).

Effect of soluble polymer binder on particle distribution ...

T1 - Effect of soluble polymer binder on particle distribution in a drying particulate coating. AU - Buss, Felix. AU - Roberts, Christine C. AU - Crawford, Kathleen S. AU - Peters, Katharina. AU - Francis, Lorraine F. PY - 2011/7/1. Y1 - 2011/7/1

Overview about Silica - kgk-rubberpoint.de

Influence of Silica-Polymer Bond Microstructure on Tire-Performance Indicators. Changes in the coupling agent structure in a silica-silane filler system lead to alterations of the microstructure of the silica-polymer interface and determine the dynamic properties, thus wet skid resistance (WSR) and rolling resistance (RR) of a tire tread. more...

Synthesis of Macrostructured Silica by Sedimentation ...

Aug 30, 2001· Synthesis of Macrostructured Silica by Sedimentation–Aggregation. S. Vaudreuil. Department of Chemical Engineering and CERSIM, Laval University, G1K 7P4, Sainte‐Foy, Québec (Canada) Search for more papers by this author. M. Bousmina.

Preparation, characterization, and sinterability of well ...

H. Giesche and E. Matijevic: Preparation, characterization, and sinterability of well-defined silica/yttria powders All samples were purified by repeated centrifugation or sedimentation steps, followed by redispersion either in ethanol or in water before the coating process was initiated and at the end of the reaction. B. Characterizations

Larsson Suspension Stability; Why Particle Size, Zeta ...

of sedimentation can then be estimated from Stokes' law (Eq. 2) assuming a dilute suspension of spherical particles2. 9 2 ga2 V (2) where V represents the sedimentation velocity and η the shear viscosity of the continuous phase. Therefore, doubling the viscosity will reduce the rate of sedimentation by the same factor, while

Effect of Interparticle Interactions on Agglomeration and ...

Apr 27, 2016· The sedimentation half-times ts of initially monodisperse dispersions of 750, 505, and 350 nm silica microspheres were measured in water, in ethanol, and in aqueous NaBr solutions of concentration cNaBr ranging from 50 to 1000 mM, where the particles may have formed clusters. In water and in ethanol, ts was about 8, 18, and 33 h for the 750, 505, and 350 nm particles, respectively. …

Influence of colloidal silica sol ... - Northwestern Scholars

T1 - Influence of colloidal silica sol on fresh properties of cement paste as compared to nano-silica powder with agglomerates in micron-scale. AU - Kong, Deyu. AU - Corr, David J. AU - Hou, Pengkun. AU - Yang, Yang. AU - Shah, Surendra P. PY - 2015/10/15. Y1 - 2015/10/15

Sol–gel process - Wikipedia

The Stöber process is a well-studied example of polymerization of an alkoxide, specifically TEOS.The chemical formula for TEOS is given by Si(OC 2 H 5) 4, or Si(OR) 4, where the alkyl group R = C 2 H 5. Alkoxides are ideal chemical precursors for sol–gel synthesis because they react readily with water. The reaction is called hydrolysis, because a hydroxyl ion becomes attached to the silicon ...

On the Microstructure of Geyserites and Hyalites, Natural ...

The submicron structures of two natural hydrous forms of silica (geyserites from Iceland, hyalite from Valec CS) have been studied by scanning electron microscopy, small-angle and wide-angle X-ray scattering. All geyserites investigated are particulate with a nonuniform size distribution.

HRTEM of microcrystalline opal in chert and porcelanite ...

@article{osti_569837, title = {HRTEM of microcrystalline opal in chert and porcelanite from the Monterey Formation, California}, author = {Cady, S L and Wenk, H R and Downing, K H}, abstractNote = {Microcrystalline opal was investigated using low-dose transmission electron microscopy (TEM) methods to identify microstructural characteristics and possible phase-transformation mechanisms that ...