scispace - formally typeset
Search or ask a question

Showing papers on "Volume fraction published in 2020"


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the convection of a nano-encapsulated phase change materials (NEPCM) suspension in a cavity with a hot wall having a time-periodic temperature.

119 citations


Journal ArticleDOI
TL;DR: In this article, the authors optimized the curved fiber trajectories to realize variable fiber volume fraction and stiffness composites (VVfSC) using a continuous fiber composite 3D printer.

111 citations


Journal ArticleDOI
TL;DR: In order to investigate the bonding behavior between reactive powder concrete (RPC) and normal strength concrete (NSC), splitting tensile test of 81 specimens and double shear test of 27 specimens were conducted, the effects of water-to-binder ratio (W/B) of RPC, steel fibre volume fraction, and interfacial roughness on RPC-NSC bonding were investigated as mentioned in this paper.

110 citations


Journal ArticleDOI
TL;DR: In this paper, flexible pressure sensors based on PVDF-PZT nanocomposite with different PZT volume fractions were prepared in the form of fibers through an electrospinning method for piezoelectric energy harvesting application.

99 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated heat and mass transfer in a hybrid nanofluid flow impinging upon a cylindrical bluff-body embedded in porous media and featuring homogenous and heterogeneous chemical reactions.

83 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the effect of nanoparticles of Al2O3-MWCNT presence on the thermal conductivity of engine oil (10W40) base fluid.

68 citations


Journal ArticleDOI
TL;DR: In this paper, two models for the tensile modulus of composites and blends are joined, assuming the dispersion and networking of carbon nanotubes (CNTs) and the interphases around CNTs in polymer nanocomposites after the percolation threshold.
Abstract: In this work, two models for the tensile modulus of composites and blends are joined, assuming the dispersion and networking of carbon nanotubes (CNTs) and the interphases around CNTs in polymer nanocomposites after the percolation threshold. Equations are given to express the percolation threshold, the network fraction, and the fractions of interphases in the nanocomposites. The suggested model predicts the tensile modulus in several samples, and the roles and efficiencies of all parameters in the nanocomposite modulus are determined. CNT radius (R) and interphase thickness (t) as well as the modulus (EiN) and volume fraction ( ϕ i N ) of the interphase surrounding the CNT network have the most important influences on the modulus; R = 10 nm and t = 35 nm produced a 400% improvement in the modulus of nanocomposite compared to the neat polymer matrix.

65 citations


Journal ArticleDOI
TL;DR: In this article, quantitative crystallographic and microstructural analyses of carbide phases are performed on wrought samples, samples fabricated via additive manufacturing (AM), and samples that underwent hot isostatic pressing (HIP) after AM of alloy Inconel 718 (IN718).
Abstract: In this work, quantitative crystallographic and microstructural analyses of γ, γ′, γ″, δ, and MC carbide phases are performed on wrought samples, samples fabricated via additive manufacturing (AM), and samples that underwent hot isostatic pressing (HIP) after AM of alloy Inconel 718 (IN718). In doing so, an advanced neutron diffraction-based procedure is developed facilitating the determination of volume fractions of every detectable phase in the alloy. To supplement the diffraction procedure, precipitate sizes are measured by scanning electron microscopy. Moreover, semi-quantitative elemental analyses are performed by energy dispersive spectroscopy. Finally, image thresholding is carried out on micrographs of samples that underwent cathodic dissolution to create secondary electron contrast between phases to verify the phase fractions determined from the neutron diffraction datasets. The study reveals a significantly higher volume fraction of δ phase and a significantly lower volume fraction of γ″ phase governing a higher strength of the AM material relative to the lower strength AM + HIP and wrought materials. Furthermore, γ′ and MC volume fractions are found similar in the materials despite the differences in MC morphology, elemental composition and distribution controlling the dispersion strengthening. These results are presented and discussed in this paper along with the procedure developed for determining volume fractions of all detectable phases present in the alloy.

62 citations


Journal ArticleDOI
21 May 2020-Symmetry
TL;DR: This work is devoted to the investigation of a two-dimensional porous material under weak, strong and normal conductivity, using the eigenvalues method, and the derived technique is assessed with numerical results that are obtained from the porous mediums using simplified symmetric geometry.
Abstract: This work is devoted to the investigation of a two-dimensional porous material under weak, strong and normal conductivity, using the eigenvalues method. By using Laplace–Fourier transformations with the eigenvalues technique, the variables are analytically obtained. The derived technique is assessed with numerical results that are obtained from the porous mediums using simplified symmetric geometry. The results, including the displacements, temperature, stresses and the change in the volume fraction field, are offered graphically. Comparisons are made among the outcomes obtained under weak, normal and strong conductivity.

61 citations


Journal ArticleDOI
TL;DR: In this article, the influence of pressure on the combustion characteristics (i.e., ignition, volatiles combustion, char combustion) of a single lignite particle was investigated in a pressurized visualized fluidized bed combustor under O 2 N 2 and O 2 CO 2 atmospheres.

61 citations


Journal ArticleDOI
TL;DR: In this article, the authors explored the significance of thermal radiation on mixed convective boundary layer flow of a hybrid (SiO2-MoS2/H2O) nanofluid.

Journal ArticleDOI
Mohsen Izadi1
TL;DR: In this paper, the impact of porous materials, nano-particle types, and their concentrations on transient natural convection heat transfer of nano-fluid inside a porous chamber with a triangular section was numerically investigated.

Journal ArticleDOI
TL;DR: In this article, the effect of the aspect ratio of the fillers on the fracture toughness of the glass-filled epoxy composites under impact loading was discussed and the potential of using Artificial Neural Networks (ANNs) in predicting the shape of the filler shape on fracture behavior was studied.

Journal ArticleDOI
TL;DR: In this paper, the wear resistance and microhardness behavior of hybrid nanocomposites with different volume fractions of SiC and BN nano-powders were investigated experimentally.

Journal ArticleDOI
TL;DR: In this article, the effects of the ceramic volume fraction on the microstructure and hardness of the produced TiC/H13 composite were obtained, and the results indicated that preheating conbined with slowing laser beam scanning speed were relatively useful for crack suppression and formation of composites with high TiC volume fraction.
Abstract: Coarse TiC particles (more than 50 μm) reinforced H13 steel composites produced by laser cladding with various ceramic volume fraction were investigated. The effects of the ceramic volume fraction on the microstructure and hardness of the produced TiC/H13 composite were obtained. The results indicated that preheating conbined with slowing laser beam scanning speed were relatively useful for crack suppression and formation of composites with high TiC volume fraction. The microstructure of the TiC/H13 composite consisted of various TiC particles, including coarse TiC, initial fine TiC, primary TiC, lamellar-type eutectic TiC, austenite and martensite. By increasing the concentration of TiC in the composite, the volume fraction of residual austensute and the carbon content of martensite as well as the composite hardness had a significant increase. Nanoindentation hardness results showed that the hardness of the initial TiC particle was the highest, followed by the primary TiC, among the various shaped TiC within the deposit. The highest average hardness of the TiC/H13 composite was 1365 HV, which was more than twice as much as the H13 substrate hardness.

Journal ArticleDOI
01 Feb 2020-Symmetry
TL;DR: Based on the sensitivity analysis, the effect of thermal conductivity of the base fluid on the overall thermal Conductivity of nanofluids is more remarkable compared with the other inputs such as volume fraction, temperature, and dimensions of the particles which are used as the inputs of the models.
Abstract: The existence of solid-phase nanoparticles remarkably improves the thermal conductivity of the fluids. The enhancement in this property of the nanofluids is affected by different items such as the solid-phase volume fraction and dimensions, temperature, etc. In the current paper, three different mathematical models, including polynomial correlation, Multivariate Adaptive Regression Spline (MARS), and Group Method of Data Handling (GMDH), are applied to forecast the thermal conductivity of nanofluids containing MgO particles. The inputs of the model are the base fluid thermal conductivity, volume concentration, and average dimension of solid-phase, and nanofluids’ temperature. Comparing the proposed models revealed higher confidence of GMDH in estimating the thermal conductivity, which is attributed to its complicated structure and more appropriate consideration of the input’s interaction. The values of R-squared for the correlation, MARS, and GMDH are 0.9949, 0.9952, and 0.9991, respectively. In addition, based on the sensitivity analysis, the effect of thermal conductivity of the base fluid on the overall thermal conductivity of nanofluids is more remarkable compared with the other inputs such as volume fraction, temperature, and dimensions of the particles which are used as the inputs of the models.

Journal ArticleDOI
Yichao Wang1, Feichi Liu1, Jiangtao Yu1, Fangyuan Dong1, Junhong Ye1 
TL;DR: A series of experiments were conducted to study the effect of polyethylene (PE) fiber content (0, 1, 1.5% and 2% volume fraction) on mesoscopic and macroscopic behaviors of the engineered cementitious composites (ECC) as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this article, the densification behavior and toughening mechanisms of ZrB2-based composites with in-situ formed ZrC were investigated, and the formation of secondary phases and their effects on densification, and mechanical behavior of the composites were discussed.

Journal ArticleDOI
TL;DR: In this article, the thermal conductivity and viscosity of 1-4-volume bentonite particles dispersed in n-pentadecane were measured at temperatures between 298 k and 393 k.

Journal ArticleDOI
TL;DR: In this paper, the effect of varying the solids volume fraction of an aqueous clay paste suspension on its printability via additive manufacturing (AM) or 3D printing technique, Direct Ink Writing (DIW) or material extrusion, has been studied.
Abstract: The effect of varying the solids volume fraction of an aqueous clay paste suspension on its printability via an Additive Manufacturing (AM) or 3D printing technique, Direct Ink Writing (DIW) or material extrusion, has been studied. DIW is a cost-effective and straightforward fabrication technology suitable for adoption at a larger scale by the traditional ceramics industry and the creative community. The pastes were prepared with volume fraction of solids ranging from 25–57 vol%. Their rheological properties (storage modulus and apparent yield stress) were measured by dynamic oscillatory rheometry. The relationships between solids content, rheological behaviour and print parameters were evaluated. An equation based on rheological properties to delineate between printable and non-printable conditions has been proposed. Several decorative pieces have been produced for architectural purposes.

Journal ArticleDOI
01 Jan 2020
TL;DR: In this paper, the impact of multiple slips on the Jeffrey fluid model for unsteady magnetohydrodynamic viscoelastic buoyant nanofluid in the presence of Soret and radiation over a permeable stretching sheet is investigated.
Abstract: The current study investigates the impact of multiple slips on Jeffrey fluid model for unsteady magnetohydrodynamic viscoelastic buoyant nanofluid in the presence of Soret and radiation over a permeable stretching sheet. Appropriate transformations are utilized to obtain the relevant nonlinear differential system. The obtained differential system is tackled numerically with the finite element method. Effect of the controlling parameters on dimensionless quantities such as velocity, temperature, concentration, and nano-fluid volume fraction profile, as well as on dimensionless numbers such as local Nusselt, Sherwood, nano-particle Sherwood, and the local friction coefficient is analyzed. The effect of multiple slips is examined and found that the boundary layer flow increases in the presence of multiple slips. Numerically obtained solutions are contrasted with the published literature and found to be in nice agreement. The present study has many applications in coating and suspensions, cooling of metallic plate, paper production, heat exchangers technology, and materials processing exploiting.

Journal ArticleDOI
TL;DR: In this article, a numerical solution for free vibration analysis of nanocomposite conical shells is proposed, where the First-Order Shear Deformation Theory (FSDT) is used to achieve the governing equations.

Journal ArticleDOI
TL;DR: The most striking result is that for curved shells, the unstable postbuckling response of the baseline material can be turned into a globally stable response maintaining the same amount of nanostructural reinforcement but simply tailoring strategically its distribution.
Abstract: Carbon nanotube/polymer nanocomposite plate- and shell-like structures will be the next generation lightweight structures in advanced applications due to the superior multifunctional properties combined with lightness. Here material optimization of carbon nanotube/polymer nanocomposite beams and shells is tackled via ad hoc nonlinear finite element schemes so as to control the loss of stability and overall nonlinear response. Three types of optimizations are considered: variable through-the-thickness volume fraction of random carbon nanotubes (CNTs) distributions, variable volume fraction of randomly oriented CNTs within the mid-surface, aligned CNTs with variable orientation with respect to the mid-surface. The collapse load, which includes both limit points and deformation thresholds, is chosen as the objective/cost function. An efficient computation of the cost function is carried out using the Koiter reduced order model obtained starting from an isogeometric solid-shell model to accurately describe the point-wise material distribution. The sensitivity to geometrical imperfections is also investigated. The optimization is carried out making use of the Global Convergent Method of Moving Asymptotes. The extensive numerical analyses show that varying the volume fraction distribution as well as the CNTs orientation can lead to significantly enhanced performances towards the loss of elastic stability making these lightweight structures more stable. The most striking result is that for curved shells, the unstable postbuckling response of the baseline material can be turned into a globally stable response maintaining the same amount of nanostructural reinforcement but simply tailoring strategically its distribution.

Journal ArticleDOI
TL;DR: In this article, numerical simulation of water-copper nanofluid flow in a three-dimensional nanochannel with different types of surface roughness geometry using molecular dynamics simulation (MDS) is performed.

Journal ArticleDOI
TL;DR: Property of concrete was investigated with individual and combined incorporation of steel fiber and micro-silica and it was revealed that varying fiber dosage showed mixed effects on the compressive strength and elastic modulus and permeability properties of concrete.
Abstract: For the efficient and durable design of concrete, the role of fiber-reinforcements with mineral admixtures needs to be properly investigated considering various factors such as contents of fibers and potential supplementary cementitious material. Interactive effects of fibers and mineral admixtures are also needed to be appropriately studied. In this paper, properties of concrete were investigated with individual and combined incorporation of steel fiber (SF) and micro-silica (MS). SF was used at six different levels i.e., low fiber volume (0.05% and 0.1%), medium fiber volume (0.25% and 0.5%) and high fiber volume (1% and 2%). Each volume fraction of SF was investigated with 0%, 5% and 10% MS as by volume of binder. All concrete mixtures were assessed based on the results of important mechanical and permeability tests. The results revealed that varying fiber dosage showed mixed effects on the compressive (compressive strength and elastic modulus) and permeability (water absorption and chloride ion penetration) properties of concrete. Generally, low to medium volume fractions of fibers were useful in advancing the compressive strength and elastic modulus of concrete, whereas high fiber fractions showed detrimental effects on compressive strength and permeability resistance. The addition of MS with SF is not only beneficial to boost the strength properties, but it also improves the interaction between fibers and binder matrix. MS minimizes the negative effects of high fiber doses on the properties of concrete.

Journal ArticleDOI
TL;DR: ZnO-SnO2 core-shell nanowires (C-S NWs) with different shell thicknesses (0-120 nm) were prepared and their sensing behavior was systematically studied as discussed by the authors.
Abstract: ZnO-SnO2 core-shell nanowires (C-S NWs) with different shell thicknesses (0–120 nm) were prepared and their sensing behavior was systematically studied. ZnO-SnO2 C-S NWs were prepared using a two-step synthesis procedure, where core ZnO NWs were synthesized by a vapor-liquid-solid growth technique, and subsequently these cores were coated with SnO2 shell layers by using an advanced atomic layer deposition technique. The sensors were exposed to 10-ppm CO, C6H6, and C7H8 gases at an optimal working temperature. The shell thickness was optimized to be 40 nm, for which the sensor revealed the highest sensitivity and fastest dynamics to the above-mentioned gases. The sensing mechanism was discussed in detail and the dominant mechanism was related to the radial modulation effect as well as the volume fraction of the shell to the total volume of C-S NWs.

Journal ArticleDOI
TL;DR: In this article, the dynamic fracture toughness of silica filled polymer composites subjected to impact loading was studied using three different loading rates corresponding to different pulse shaper conditions, and the results showed that loading rate was the most important factor in predicting the stress intensity factor followed by shear wave speed, longitudinal wave speed and volume fraction of the fillers used.

Journal ArticleDOI
Liu Tengfei1, Xiaoyong Tian1, Yayuan Zhang1, Cao Yi1, Dichen Li1 
TL;DR: A micro-screw in-situ extrusion process was utilized to obtain high pressure for good impregnation and high fiber fraction of 3D printed continuous carbon fiber reinforced nylon (PA12) composites as mentioned in this paper.
Abstract: A micro-screw in-situ extrusion process was utilized to obtain high pressure for good impregnation and high fiber fraction of 3D printed continuous carbon fiber reinforced nylon (PA12) composites. Nylon pellets and different carbon fiber strand bundles (1 K and 3 K) were used as raw materials to print composites with different process parameters. Almost full impregnation for 1 K continuous carbon fiber (CCF) reinforced PA12 composites (1 K-CCF/PA12) with only 0.15% porosity and good impregnation for 3 K continuous carbon fiber reinforced PA12 composites (3 K-CCF/PA12) with 2.62% porosity achieved. Fiber volume fraction was dramatically improved from 31.9 vol% for 1 K-CCF/PA12 to 50.2 vol% for 3 K-CCF/PA12. Mechanical properties of different composites were measured systematically. Excellent longitudinal tensile strength and modulus of 735.7 MPa and 79.5 GPa, and simultaneously flexural strength and modulus of 772.6 MPa and 85.3 GPa for 3 K-CCF/PA12 were obtained. This novel 3D printing of continuous fiber reinforced composite process realized the integration of composites preparation and formation with enhanced impregnation, high fiber fraction and mechanical performance which could expand the applications of this technology to more and more industry fields.

Journal ArticleDOI
TL;DR: It is generally believed that the spherical domains self-assembled from AB-type block copolymers are composed of the minority A blocks with a volume fraction of fA < 1/2 as discussed by the authors.
Abstract: It is generally believed that the spherical domains self-assembled from AB-type block copolymers are composed of the minority A blocks with a volume fraction of fA < 1/2. Breaking this generic rule...

Journal ArticleDOI
TL;DR: In this article, the authors investigated the effects of water-based single-walled carbon nanotubes on free convection in a partially heated right trapezoidal cavity, where bottom wall of the cavity is heated while the side walls are kept cold, and the top wall is adiabatic.