Influence of Polymer Modification on the Microstructure of Shielding Concrete

In this paper an analysis of the influence of polymer modification on the microstructure, shielding properties against neutrons, and compressive strength of heavy-weight magnetite concrete is carried out. The modifications involve the addition of acrylic or epoxy dispersions as well as micro- or/and macrofibers. A computer image analysis method is used to evaluate the microstructure of concretes and parameters of pore structure are calculated; these parameters include relative volume fraction, relative specific surface area, and pore arrangement ratios, including a proprietary ratio based on Voronoi tessellation. An assessment of significance of differences between stereological parameters of reference concrete and polymer modified concretes, as well as the impact of polymer form (dispersion or fibers) on shielding properties and compressive strength is carried out using Student’s t-test. The results show that except for the effect of the addition of both polypropylene micro- and macrofibers on the relative volume of pores, all other modifications result in statistically significant changes in the values of stereological parameters. Nevertheless, it is shown that neither polymer dispersions nor fibers have a statistically significant impact on shielding properties, but that they do influence compressive strength.

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Analysis of CFRP Laminates Properties under Different Layup Structure using Finite Element Analysis

Structural Health Monitoring ◽

10.21741/9781644901311-30 ◽

2021 ◽

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Composite Laminates ◽

Volume Fraction ◽

Relative Volume ◽

Low Velocity Impact ◽

Element Analysis ◽

Relative Volume Fraction ◽

Cfrp Laminates ◽

The Impact

Abstract. In order to study the effect of the layup structure on the static strength and low-velocity impact strength of carbon fiber/epoxy composite (CFRP) laminates, theoretical simulation analysis under different laying angles have been carried out. In this study, Finite Element Analysis (FEA) models for different CFRP laminate specimens are created using ANSYS Workbench by changing the relative volume fraction of 0°, 45° and 90° plies in each specimen and their relative location. The FEA results revealed that the increase of relative volume of 90° ply will improve the impact the impact resistance performance, while the increase of relative volume of 45° ply will take the opposite effect. Moreover, when the relative volume fraction of 0°, 45° and 90° plies are the same, the strength performance of the laminate cannot be improved by changing the thickness of the outermost layer. The study illustrated the significant effects of different stacking sequences and laying angles on the tensile and flexural failure mechanisms in composite laminates, leading to some suggestions to improve the design of composite laminates.

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Thermoplasmonic of Single Au@SiO2 and SiO2@Au Core Shell Nanoparticles in Deionized Water and Poly-vinylpyrrolidoneMatrix

Baghdad Science Journal ◽

10.21123/bsj.2019.16.2.0376 ◽

2019 ◽

Vol 16 (2) ◽

pp. 0376 ◽

Cited By ~ 2

Author(s):

Gatea Et al.

Keyword(s):

Light Propagation ◽

Volume Fraction ◽

Relative Volume ◽

Core Shell ◽

Distribution Profile ◽

Shell Nanoparticles ◽

Thermal Generation ◽

Relative Volume Fraction ◽

Core Shell Nanoparticles ◽

532 Nm

Metal nanoparticles can serve as an efficient nano-heat source with confinement photothermal effects. Thermo-plasmonic technology allows researchers to control the temperature at a nanoscale due to the possibility of precise light propagation. The response of opto-thermal generation of single gold-silica core-shell nanoparticle immersed in water and Poly-vinylpyrrolidone surrounding media is theoretically investigated. Two lasers (CW and fs pulses) at the plasmonic resonance (532 nm) are utilized. For this purpose, finite element method is used via COMSOL multiphysics to find a numerical computation of absorption cross section for the proposed core –shell NP in different media. Thermo-plasmonic response for both lasers is studied. The heat profile of different nanostructures is estimated. The results revealed that the temperature distribution profile was varied due to changing in the relative volume fraction between the core and the shell of nanoparticle.

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UV-induced vesicle to micelle transition: a mechanistic study

Polymer Chemistry ◽

10.1039/c9py01259a ◽

2019 ◽

Vol 10 (44) ◽

pp. 6037-6046 ◽

Cited By ~ 3

Author(s):

Craig A. Machado ◽

Roger Tran ◽

Taylor A. Jenkins ◽

Amanda M. Pritzlaff ◽

Michael B. Sims ◽

...

Keyword(s):

Block Copolymer ◽

Volume Fraction ◽

Relative Volume ◽

Mechanistic Study ◽

Relative Volume Fraction ◽

Self Assembled

The morphology of self-assembled block copolymer aggregates is highly dependent on the relative volume fraction of the hydrophobic block.

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Research on Impact Behavior of Reactive Powder Concrete

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.150-151.779 ◽

2010 ◽

Vol 150-151 ◽

pp. 779-782

Author(s):

Qing Xin Zhao ◽

Zhao Yang Liu ◽

Jin Rui Zhang ◽

Ran Ran Zhao

Keyword(s):

Compressive Strength ◽

Impact Toughness ◽

Flexural Strength ◽

Steel Fiber ◽

Volume Fraction ◽

Impact Behavior ◽

Reactive Powder Concrete ◽

Flexural Toughness ◽

Reactive Powder ◽

The Impact

By means of the three-point bending impact equipment, with the measurement of ultrasonic velocity, the impact behavior and damage evolution of reactive powder concrete (RPC) with 0, 1%, 2% and 3% volume fraction of steel fiber were tested. The results showed that steel fiber significantly improved the compressive strength, flexural strength, flexural toughness and impact toughness of RPC matrix. The compressive strength, flexural strength, flexural toughness of RPC with 3% steel fiber increased by 40.1%, 102.1%, and 37.4 times than that of plain concrete, respectively, and simultaneously, the impact toughness of RPC with 3% steel fiber was 93.2 times higher than that with 1% steel fiber. RPC with 2% and 3% steel fiber dosage both had relatively high compressive strength, flexural strength and flexural toughness; however, compared with the sample with 2% steel fiber dosage, the impact toughness of RPC with 3% steel fiber dosage increased by more than 10 times. Therefore, taking economy and applicability into consideration, if we mainly emphasis on the compressive strength, flexural strength and flexural toughness, RPC with 2% steel fiber is optimal. While if impact toughness is critical, RPC with 3% steel fiber would be the best choice.

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Irradiation Duration Effect of Gamma Ray on the Compressive Strength of Reactive Powder Concrete

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.857.15 ◽

2020 ◽

Vol 857 ◽

pp. 15-21

Author(s):

Nesreen B. Najib ◽

Shatha D. Mohammed ◽

Wasan Z. Majeed ◽

Nada Mahdi Fawzi A. Jalawi

Keyword(s):

Compressive Strength ◽

Fiber Volume Fraction ◽

Gamma Ray ◽

Volume Fraction ◽

Reactive Powder Concrete ◽

Fiber Volume ◽

Gamma Ray Irradiation ◽

Duration Effect ◽

Reactive Powder ◽

The Impact

Reactive Powder Concrete (RPC) could be considered as the furthermost significant modern high compressive strength concrete. In this study, an experimental investigation on the impact of micro steel fiber volume fraction ratio and gamma ray irradiation duration influence upon the compressive strength of RPC is presented. Three volume fraction ratios (0.0, 1.0 and 1.5) % was implemented. For each percentage of the adopted fiber ratios, six different irradiation duration was considered; these are (1, 2, 3, 4, 5 and 6) days. Gamma source (Cs-137) of energy (0.662) MeV and activity (6) mci was used. In a case of zero volume fraction ratio, the experimental results showed that gamma ray had a significant influence on the reducing of the compressive strength varies between (1.2-8.6)% for a period of (1-6) days, respectively. Although there was a decrease in the compressive strength for a state of non-zero volume fraction ratio (1 and 1.5) % varies between (1.0-3.1 and 0.4-1.6) %, respectively, the attained results indicated that gamma ray had no significant effect to reduce the compressive strength of the RPC that’s included micro steel fibers as a volume fraction.

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Degree of Mixing Analyses of Concentrated Suspensions by Electron Probe and X-Ray Diffraction

Rubber Chemistry and Technology ◽

10.5254/1.3538325 ◽

1993 ◽

Vol 66 (4) ◽

pp. 527-537 ◽

Cited By ~ 14

Author(s):

R. Yazici ◽

D. M. Kalyon

Keyword(s):

Electron Probe ◽

Volume Fraction ◽

Relative Volume ◽

Mixing Efficiency ◽

Energy Dispersive Analysis ◽

X Ray Diffraction ◽

Concentrated Suspensions ◽

Relative Volume Fraction ◽

X Ray ◽

Definition Of

Abstract Two x-ray based techniques involving energy-dispersive analysis and diffractometry were introduced to the analyses of the degree of mixedness, i.e. the “goodness of mixing” of concentrated suspensions. A hydroxyl terminated polybutadene matrix was mixed with aluminum and ammonium sulfate. In the analysis, the ratio of the relative volume fractions of the two solid components was used as the basis of the analytical evaluation. Both characterization techniques are capable of determining the relative volume fraction of the two solid components as a representative measurement of the distributive mixing efficiency and both are sensitive to the scale of examination. The introduced techniques should be useful in the better definition of the degree of mixedness as well as in resolving differences in mixing efficiencies of various mixers used in processing of concentrated suspensions.

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Dynamics of Multilayered Composite Plates With Shape Memory Alloy Wires

Journal of Applied Mechanics ◽

10.1115/1.1546263 ◽

2003 ◽

Vol 70 (3) ◽

pp. 313-327 ◽

Cited By ~ 26

Author(s):

A. J. Zak ◽

M. P. Cartmell ◽

W. Ostachowicz

Keyword(s):

Finite Element ◽

Shape Memory ◽

Volume Fraction ◽

Composite Plates ◽

Relative Volume ◽

The Finite Element Method ◽

Relative Volume Fraction ◽

Multilayered Composite ◽

Reinforcing Fibers ◽

Tuning Methods

In this paper certain aspects of the dynamic behavior of a multilayered, composite plate with shape memory alloys (SMA) wires have been investigated. The influence of parameters such as the orientation and location of SMA wires, the orientation and relative volume fraction of reinforcing fibers, the thickness-to-length and length-to-width ratios, and different boundary conditions, on changes in the critical load, the natural frequencies and the modes of vibrations of the plate have all been studied and discussed in the paper. The use of two different techniques, generally known in the literature as the active property tuning and active strain energy tuning methods, has also been investigated. The results presented in this paper have been obtained by the use of the finite element method and a new finite element formulated for multilayered composite plates has been applied for this purpose.

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EFFECTIVENESS OF USE OF NANO FILLERS OF DIFFERENT TYPES IN POLYMERIC COMPOSITES

IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA ◽

10.6060/ivkkt.20206304.6158 ◽

2020 ◽

Vol 63 (4) ◽

pp. 81-85

Author(s):

Vladimir Z. Aloyev ◽

Zaira M. Zhirikova ◽

Memunat A. Tarchokova

Keyword(s):

Fractal Dimension ◽

Polymer Nanocomposites ◽

Maximum Degree ◽

Volume Fraction ◽

Relative Proportion ◽

Relative Volume ◽

Theoretical Evaluation ◽

Relative Volume Fraction ◽

Different Types ◽

Degree Of Filling

The paper provides a theoretical analysis of the effectiveness of using different types of nanofillers to produce high-strength polymer composites. Three basic types of nanoscale inorganic nanofillers were selected: dispersed nanoparticles (0D-nanofillers), carbon nanotubes and nanofibers (1D-nanofillers), and organoclay, graphene, etc. (2D-fillers). The relative modulus of elasticity, i.e. the degree of amplification, is used as the main criterion for the effectiveness of nanofillers. Within the framework of the percolation model, the amplification levels of nanocomposites for different types of nanofillers are determined depending on the relative volume fraction of nanofillers and interfacial regions. It is shown that interfacial regions in polymer nanocomposites are treated as a reinforcing element of the nanocomposite structure. To describe the surface structure of nanofiller particles, an effective value of the fractal dimension is used, which serves as a determining factor for the relative proportion of interfacial regions. At a condition that the fractal dimension of the structural framework of nanofiller particles cannot exceed the fractal dimension of the enclosing Euclidean space, the relative proportion of interfacial regions and, through it, the maximum degree of filling for the types of nanofillers under consideration are determined. The results of the theoretical evaluation of the maximum limit value of the fractal dimension of nanofiller particles carried out in this work show that the formation of a bulk frame of particles is possible only for anisotropic nanofillers, and dispersed particles form chains that do not change the structure of the polymer matrix in comparison with the matrix polymer. It is also found that for each type of nanofiller, there is a limit maximum degree of filling, which ultimately determines the limit maximum degree of amplification of the nanocomposite. These results allow us to conclude that the most effective for creating structural polymer nanocomposites is a dispersed nanofiller.

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Influence of SiC Content on Microstructure, Dislocation Density and Mechanical Behavior of Cu/SiC Composite

Journal of University of Shanghai for Science and Technology ◽

10.51201/jusst/22/0130 ◽

2022 ◽

Vol 24 (1) ◽

pp. 186-200

Author(s):

H. A. EL-Fattah ◽

◽

M.A. Metwally ◽

M. M. Sadawy ◽

I .G.El- Batanony ◽

...

Keyword(s):

Compressive Strength ◽

Mechanical Behavior ◽

Volume Fraction ◽

Percentage Increase ◽

Sintering Process ◽

Xrd Diffraction ◽

Microstructure Examination ◽

Sic Composites ◽

The Impact ◽

Pure Cu

The present investigation has examined the impact of micro-SiC on microstructure, dislocation and mechanical behavior of Cu/SiC composite. The micro-composite samples have been fabricated under a constant pressure (480 MPa) and sintered temperature (860oC) for 2 h. The sintering process was performed under argon gas. The microstructure examination was conducted using SEM/EDS and XRD diffraction. The SiC contents were 0, 5, 10,15,20,25 and 30 volume fraction. The outcomes showed that the density was significantly decreased with an increase of silicon carbide content. The relative densities of Cu and Cu/SiC composites was ranged from 91.24% to 83.56% for pure Cu and Cu/30 vol%SiC composites. The copper crystallite size was reduced with growing SiC content while the hardness, ultimate and yield compressive strength increased with increment of SiC volume fraction to 20% vol. The values of hardness, ultimate and yield compressive strength increased to 231 HV,343 and 176 N/mm2 , respectively for the composite sample containing 20% SiC particles with a percentage increase of 75%,26.6% and 57.2% compared with pure Cu.

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