Topic
Volume fraction
About: Volume fraction is a research topic. Over the lifetime, 16312 publications have been published within this topic receiving 374181 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: A theoretical model based on three-dimensional CNT chain formation (percolation) in the base liquid and the corresponding thermal resistance network is presented and a new dimensionless parameter is introduced that alone characterizes the nanofluid thermal conductivity with reasonable accuracy.
Abstract: Adding a small volume fraction of carbon nanotubes (CNTs) to a liquid enhances the thermal conductivity significantly. Recent experimental findings report an anomalously wide range of enhancement values that continue to perplex the research community and remain unexplained. In this paper we present a theoretical model based on three-dimensional CNT chain formation (percolation) in the base liquid and the corresponding thermal resistance network. The model considers random CNT orientation and CNT–CNT interaction forming the percolating chain. Predictions are in good agreement with almost all available experimental data. Results show that the enhancement critically depends on the CNT geometry (length), volume fraction, thermal conductivity of the base liquid and the nanofluid (CNT–liquid suspension) preparation technique. Based on the physical mechanism of heat conduction in the nanofluid, we introduce a new dimensionless parameter that alone characterizes the nanofluid thermal conductivity with reasonable accuracy (~ ± 5%).
113 citations
TL;DR: In this article, the phase behavior of a melt of monodisperse rod−coil diblocks is studied and a Landau free energy functional for both a compositional and a nematic order parameter is derived.
Abstract: The phase behavior of a melt of monodisperse rod−coil diblocks is studied. We derive a Landau free energy functional for both a compositional and a nematic order parameter. The excluded volume interaction between the rod blocks is modeled by an attractive Maier−Saupe interaction. The incompatibility between rod and coil blocks is modeled by the usual Flory−Huggins interaction. For a large volume fraction of the rods, a transition from isotropic to nematic to smectic C is observed upon decreasing the temperature, whereas for small rod volume fraction, spherical, hexagonal, and lamellar structures prevail. In the smectic C phase, the rod orientation angle with respect to the lamellar normal increases rapidly from 35 to 40° close to the nematic/smectic-C phase boundary to values between 45 and 55°.
112 citations
TL;DR: In this paper, a procedure has been developed for determining expressions for the volume fraction crystallized and for the kinetic parameters in non-isothermal reactions in solid systems involving the formation and growth of nuclei.
112 citations
TL;DR: In this paper, the effective viscosity of short-fiber suspensions is studied from a theoretical and experimental point of view, and it is shown that the intrinsic viscosities determined are higher than theoretically predicted via the Brenner formula, while the critical volume fraction is lower than predicted by the empirical Kitano relation.
Abstract: The effective viscosity of short-fiber suspensions is studied from a theoretical and experimental point of view. The theory of dilute suspensions with elongated particles is briefly summarized and explicit formulae for the dependence of the intrinsic viscosity on the particle shape (aspect ratio) are given in a form that should be useful for practical purposes. Concentration regimes, the influence of Brownian motion and sedimentation kinetics are mentioned. The effective viscosity of suspensions of two polydisperse wollastonites with significantly different average aspect ratios (approximately 5 and 16, respectively) is measured in dependence of the solids volume fraction and fitted with power-law models (Krieger and Maron–Pierce relations). It is shown that the intrinsic viscosity determined is higher than theoretically predicted via the Brenner formula, while the critical volume fraction is lower than predicted by the empirical Kitano relation. Possible reasons for these discrepancies, common to most real polydisperse systems, are discussed.
112 citations
TL;DR: In this article, the volume fraction of the β phase was found to have a significant influence on the corrosion behavior of AZ91D alloy ingots, and the results support the idea of microgalvanic coupling between cathodic β phase and anodic α matrix.
Abstract: An AZ91D ingot in the as-cast condition was homogenized by solution treatment and then aged for various periods of time The microstructures produced were studied in detail and the β phase volume fraction was measured quantitatively The Corrosion resistance of all the different microstructures was studied in 35% NaCl solution through weight loss measurement in constant immersion conditions and potentiodynamic polarization experiments The corroded surfaces were analysed using SEM and XRD The volume fraction of the β phase was found to have a significant influence on the corrosion behaviour The T4 condition improved the corrosion resistance of AZ91D alloy compared to the T6 heat treatment The results support the idea of microgalvanic coupling between cathodic β phase and anodic α matrix
112 citations