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Volume fraction

About: Volume fraction is a research topic. Over the lifetime, 16312 publications have been published within this topic receiving 374181 citations.


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Journal ArticleDOI
TL;DR: A colloidal suspension confined between two quasiparallel walls is used as a model system for glass transitions in confined geometries and confocal microscopy is used to directly observe the motion of colloidal particles.
Abstract: We study a colloidal suspension confined between two quasiparallel walls as a model system for glass transitions in confined geometries. The suspension is a mixture of two particle sizes to prevent wall-induced crystallization. We use confocal microscopy to directly observe the motion of colloidal particles. This motion is slower in confinement, thus producing glassy behavior in a sample which is a liquid in an unconfined geometry. For higher volume fraction samples (closer to the glass transition), the onset of confinement effects occurs at larger length scales.

130 citations

Journal ArticleDOI
14 Feb 2012-Langmuir
TL;DR: The microstructural origins of this behavior are investigated by confocal microscopy and reveal a percolating network of colloidal particles that serves as a cohesive scaffold, bridging together droplets of the dispersed phase.
Abstract: We experimentally characterize the microstructure and rheology of a carefully designed mixture of immiscible fluids and near-neutral-wetting colloidal particles. Particle bridging across two fluid interfaces provides a route to highly stable gel-like emulsions at volume fractions of the dispersed phase well below the random close-packing limit for spheres. We investigate the microstructural origins of this behavior by confocal microscopy and reveal a percolating network of colloidal particles that serves as a cohesive scaffold, bridging together droplets of the dispersed phase. Remarkably, the mixture’s salient rheological characteristics are governed predominantly by the solids loading and can be tailored irrespective of the droplet volume fraction. The identification of this rheological hallmark could provide a means toward the improved design of modern products that utilize solid-stabilized interfaces.

130 citations

Journal ArticleDOI
TL;DR: In this paper, the thermal conductivity of magnetite nanofluid has been studied as a function of transverse magnetic field and temperature, and the authors found almost 30% enhancements in thermal conductivities for 4.7% volume fraction.
Abstract: Magnetite nanofluid is synthesized using continuous chemical process. Powder x-ray diffraction and transmission electron microscopy show single phase spinel structure with size of 9.83 and 9.9 nm, respectively. Thermal conductivity of magnetite nanofluid has been studied as a function of transverse magnetic field and temperature. We found almost 30% enhancements in thermal conductivity for 4.7% volume fraction under transverse magnetic field. This result is explained on the basis of formation of continuous three-dimensional zipperlike structure of magnetic nanoparticles inside magnetic fluid. The temperature dependent thermal conductivity shows no enhancement in the temperature region of 25–65 °C.

130 citations

Journal ArticleDOI
TL;DR: In this paper, the dependences of the dielectric properties of the composites on PZT volume fraction are reported and analyzed in terms of an analytical model, and the pyroelectric properties were determined using dynamical experimental setups, and are given in termsof pyro electric coefficient and figures of merit.
Abstract: Thick films of 0–3 composites of lead–zirconate–titanate (PZT) particulate and polyvinylidene-trifluoroethylene (PVDF-TrFE) copolymer have been produced by screen-printing on indium–tin-oxide (ITO)-coated glass substrates. The microstructure was investigated using scanning electron microscopy and X-ray diffraction. The dependences of the dielectric properties of the composites on PZT volume fraction are reported and analyzed in terms of an analytical model. The pyroelectric properties were determined using dynamical experimental setups, and are given in terms of pyroelectric coefficient and figures of merit. The piezoelectric response was investigated as a function of the PZT volume fraction using a laser vibrometer. The piezoelectric charge coefficient, d 33,eff , is shown to exhibit a minimum at a PZT volume fraction of 40% which arises from the piezoelectric charge coefficients of the pure constituents being of opposite sign. It is thought that screen-printing of these composites constitutes a cost-effective way of producing structured functional thin films for pyroelectric and piezoelectric applications.

130 citations

Journal ArticleDOI
TL;DR: In this paper, an analytical model for the effective thermal conductivity in graphene nanoplates (GNPs) based composites is presented and the theoretical formula gives good agreements with the existing experimental data available in the literature.
Abstract: An analytical model for the effective thermal conductivity in graphene nanoplates (GNPs) based composites is presented. The theoretical formula gives good agreements with the existing experimental data available in the literature. In particular, the present model well shows the nonlinear dependence of effective thermal conductivity enhancement ((Ke − Km)/Km) on the GNP volume fraction (f), and it yields a power law (Ke − Km)/Km ∼ f α (1/2 < α < 2) (1/2 < α < 2). Some interesting findings in thermal conductivity behavior of GNP composites based on the present model are also discussed.

129 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023965
20222,020
2021744
2020736
2019786
2018696